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Liang CK, Lee WJ, Chou MY, Hwang AC, Lin CS, Peng LN, Hsiao FY, Loh CH, Chen LK. Roles of Baseline Intrinsic Capacity and its Subdomains on the Overall Efficacy of Multidomain Intervention in Promoting Healthy Aging among Community-Dwelling Older Adults: Analysis from a Nationwide Cluster-Randomized Controlled Trial. J Prev Alzheimers Dis 2024; 11:356-365. [PMID: 38374742 DOI: 10.14283/jpad.2024.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
BACKGROUND Impaired intrinsic capacity (IC), which affects approximately 90% of older adults, is associated with a significantly heightened risk of frailty and cognitive decline. Existing evidence suggests that multidomain interventions have the potential to enhance cognitive performance and yield positive effects on physical frailty. OBJECTIVE To examine roles of baseline IC and its subdomains on the efficacy of multidomain interventions in promoting healthy aging in older adults. DESIGN a cluster-randomized controlled trial. SETTING AND PARTICIPANTS 1,054 community-dwelling older adults from 40 community-based clusters across Taiwan. INTERVENTION A 12-month pragmatic multidomain intervention of exercise, cognitive training, nutritional counseling and chronic condition management. MEASUREMENTS Baseline IC was measured by 5 subdomains, including cognition (Montreal Cognitive Assessment, MoCA), sensory (visual and hearing impairment), vitality (handgrip strength or Mini-Nutritional Assessment-short form), psychological well-being (Geriatric Depression Scale-5), and locomotion (6m gait speed). Outcomes of interest were cognitive performance (MoCA scores) and physical frailty (CHS frailty score) over a follow-up period of 6 and 12 months. RESULTS Of all participants (mean age:75.1±6.4 years, 68.6% female), about 90% participants had IC impairment at baseline (2.0±1.2 subdomains). After covariate adjustment using a generalized linear mixed model (GLMM), the multidomain intervention significantly prevented cognitive declines and physical frailty, particularly in those with IC impairment ≥ 3 subdomains (MoCA: coefficient: 1.909, 95% CI: 0.736 ~ 3.083; CHS frailty scores: coefficient = -0.405, 95% CI: -0.715 ~ -0.095). To assess the associations between baseline poor capacity in each IC subdomain and MoCA/CHS frailty scores over follow-up, a 3-way interaction terms (time*intervention*each poorer IC subdomains) were added to GLMM models. Significant improvements in MoCA scores were shown for participants with poorer baseline cognition (coefficient= 1.138, 95% CI: 0.080 ~ 2.195) and vitality domains (coefficient= 1.651, 95% CI: 0.541 ~ 2.760). The poor vitality domain also had a significant modulating effect on the reduction of CHS frailty score after the 6- and 12-month intervention period (6 months: coefficient= -0.311, 95% CI: -0.554 ~ -0.068; 12 months: coefficient= -0.257, 95% CI: -0.513 ~ -0.001). CONCLUSION AND IMPLICATIONS A multidomain intervention in community-dwelling older adults improves cognitive decline and physical frailty, with its effectiveness influenced by baseline IC, highlighting the importance of personalized strategies for healthy aging.
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Affiliation(s)
- C-K Liang
- Liang-Kung Chen, MD, PhD, Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Rd., Taipei 11217, Taiwan. E-mail addresses: (L. K. Chen). Tel: +886-2-28757830
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Wang YC, Liang CK, Chou MH, Chiu CF, Lin HC, Hsu YH, Liao MC, Yin CH, Chou MY, Lin YT. The Effectiveness of Frailty Intervention for Older Patients with Frailty during Hospitalization. J Nutr Health Aging 2023; 27:413-420. [PMID: 37357324 DOI: 10.1007/s12603-023-1924-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/16/2023] [Indexed: 06/27/2023]
Abstract
OBJECTIVES This study aims to assess the effectiveness of a multidomain intervention program on the change in functional status of hospitalized older adults. DESIGN This single-arm, prospective, non-randomized interventional study investigates the efficacy of a multidomain interventional program including cognitive stimulation activity, simple exercises, frailty education, and nutrition counseling. SETTING AND PARTICIPANTS At a tertiary hospital in southern Taiwan, 352 eligible patients were sequentially enrolled. Included patients were aged ≥65 years (mean age, 79.6 ± 9.0 years; 62% male), scored 3-7 on the Clinical Frailty Scale (CFS), and were hospitalized in the geriatric acute ward. INTERVENTION Those receiving standard care (physical rehabilitation and nutrition counseling) during January-July 2019 composed the historical control group. Those receiving the multidomain intervention during August-December 2019 composed the intervention group. MEASUREMENTS The primary outcome was the change in activities of daily life (ADL) and frailty status, as assessed by Katz Index and Clinical Frailty Scale, with using the generalized estimating equation model. The length of hospital stay, medical costs, and re-admission rates were secondary outcomes. RESULTS Participants undergoing intervention (n = 101; 27.9%) showed greater improvements in the ADL and CFS during hospitalization (ADL adjusted estimate, 0.61; 95% CI, 0.11-1.11; p = 0.02; CFS adjusted estimate, -1.11; 95% CI, -1.42- -0.80; p < 0.01), shorter length of hospital stay (adjusted estimate, -5.00; 95% CI, -7.99- -2.47; p < 0.01), lower medical costs (adjusted estimate, 0.58; 95% CI, 0.49-0.69; p < 0.01), and lower 30- and 90-day readmission rates (30-day adjusted OR [aOR], 0.12; 95% CI, 0.27-0.50; p < 0.01; 60-day aOR, 0.04; 95% CI, 0.01-0.33; p < 0.01) than did controls. CONCLUSIONS Participation in the multidomain intervention program during hospitalization improved the functional status and decreased the hospital stay length, medical costs, and readmission rates of frail older people.
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Affiliation(s)
- Y-C Wang
- Dr. Ming-Yueh Chou, Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, 386, Ta-Chung 1st RD. Zuoying District 813, Kaohsiung, Taiwan, TEL: +886-7-3742121 ext 2091, FAX: +886-7-3468224;
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Liang CK, Chuang HY, Hsiao FY, Chou MY, Liu TY, Yang CC, Chen LK. Prognostic Impact of Delirium in Older People With/Without Dementia: A Retrospective Cohort Study in Taiwan. J Nutr Health Aging 2020; 24:951-958. [PMID: 33155620 DOI: 10.1007/s12603-020-1459-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To elucidate the hypothetically different interactions between delirium and post-discharge prognostic indicators in elderly hospital inpatients with versus without dementia. DESIGN Retrospective cohort study of claims data by Taiwan National Health Insurance beneficiaries between 2002-2013. SETTING Records of public hospital admissions in the Taiwan National Health Insurance Research database. PARTICIPANTS Propensity-score matched subgroups of patients with delirium superimposed on dementia (n = 922) versus dementia alone (n = 922), delirium alone (n = 680) versus neither delirium nor dementia (n = 680). MEASUREMENTS Mortality, emergency department visits, readmissions, and psychotropic drug use, within 30, 180, and 365 days of discharge, were analyzed using multivariate proportional hazards or logistic regression analyses. RESULTS Delirium superimposed on dementia was not associated with increased post-discharge mortality, or emergency department visits, but significantly increased the risk of readmissions at 365-day follow-up (adjusted HR, 95% CI: 1.26, 1.01-1.56). However, delirium without dementia was significantly associated with increased post-discharge mortality, emergency department visits and readmissions at 180 days and 365 days (respective adjusted HRs: mortality, 1.63 and 1.79; adjusted ORs: emergency department visits, 1.89 and 1.81; readmissions, 1.47 and 1.53). Delirium in patients both with dementia and without, was associated with six-fold higher likelihood of in-hospital psychotropic drug use, and doubled post-discharge psychotropic drug usage. CONCLUSIONS The obvious association between in-hospital delirium and worsened long-term prognosis, irrespective of dementia, raises awareness to warrants proactive and multimodal prevention and intervention strategies. Furthermore, the mechanisms about different influence of delirium for patients with/without dementia need to be further explored.
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Affiliation(s)
- C-K Liang
- Liang-Kung Chen, Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Rd., Taipei 11217, Taiwan, ; Fei-Yuan Hsiao, Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Room 220, 33 Linen S. Rd., Taipei 10050, Taiwan, ; Chen-Chang Yang, Division of Clinical Toxicology and Occupational Medicine, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Rd., Taipei 11217, Taiwan,
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Chou MY, Hsu YH, Wang YC, Chu CS, Liao MC, Liang CK, Chen LK, Lin YT. The Adverse Effects of Physical Restraint Use among Older Adult Patients Admitted to the Internal Medicine Wards: A Hospital-Based Retrospective Cohort Study. J Nutr Health Aging 2020; 24:160-165. [PMID: 32003405 DOI: 10.1007/s12603-019-1306-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To evaluate the negative effect of physical restraint use on the hospital outcomes of older patients. DESIGN A retrospective cohort study. SETTING Internal medicine wards of a tertiary medical center in Taiwan. PARTICIPANTS Subjects aged 65 years and over who were admitted during April to Dec 2017 were recruited for study. MEASUREMENTS Demographic data, geriatric assessments (polypharmacy, visual impairment, hearing impairment, activities of daily living before and after admission, risk of pressure sores, change in consciousness level, mood condition, history of falls in the previous year, risk of malnutrition and pain) and hospital conditions (admission route, department of admission, length of hospital stay and mortality) were collected for analysis. RESULTS Overall, 4,352 participants (mean age 78.7±8.7 years, 60.2% = male) were enrolled and 8.3% had physical restraint. Results of multivariate logistic regression showed that subjects with physical restraints were at greater risk of functional decline (adjusted odds ratio 2.136, 95% confidence interval 1.322-3.451, p=0.002), longer hospital stays (adjusted odds ratio 5.360, 95% confidence interval 3.627-7.923, p<0.001) and mortality (adjusted odds ratio 4.472, 95% confidence interval 2.794-7.160, p<0.001) after adjustment for covariates. CONCLUSION The use of physical restraints during hospitalization increased the risk of adverse hospital outcomes, such as functional decline, longer length of hospital stay and mortality.
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Affiliation(s)
- M-Y Chou
- Dr. Chih-Kuang Liang, Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, 386, Ta-Chung 1st RD. Zuoying District 813, Kaohsiung, Taiwan, TEL: +886-7-3742121 ext 2091, FAX: +886-7-3468224,
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Hsu YH, Chou MY, Chu CS, Liao MC, Wang YC, Lin YT, Chen LK, Liang CK. Predictive Effect of Malnutrition on Long-Term Clinical Outcomes among Older Men: A Prospectively Observational Cohort Study. J Nutr Health Aging 2019; 23:876-882. [PMID: 31641739 DOI: 10.1007/s12603-019-1246-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVES To determine whether nutritional status can predict 3-year cognitive and functional decline, as well as 4-year all-cause mortality in older adults. DESIGN Prospectively longitudinal cohort study. SETTING AND PARTICIPANTS The study recruited 354 men aged 65 years and older in the veteran's retirement community. MEASURES Baseline nutritional status was evaluated using the Mini-Nutritional Assessment-Short Form (MNA-SF). Cognitive function and Activities of Daily Living (ADL) function were determined by the Mini-Mental State Examination (MMSE) and the Barthel Index, respectively. Three-year cognitive and functional decline were respectively defined as a >3 point decrease in the MMSE scores and lower ADL scores than at baseline. Univariate and multivariable logistic regression analyses were conducted to identify nutritional status as a risk factor in poor outcome. The Kaplan-Meier method and Cox proportional regression models were used to estimate the effect of malnutrition risk on the mortality. RESULTS According to MNS-SF, the prevalence of risk of malnutrition was 53.1% (188/354). Multivariate logistic regression found risk of malnutrition significantly associated with 3-year cognitive decline (Adjusted odds ratio [OR] 2.07, 95% Confidence Interval [CI] 1.05-4.08, P =0.036) and functional decline (Adjusted OR 1.83, 95% CI 1.01-3.34, P =0.047) compared with normal nutritional status. The hazard ratio (HR) for all-cause mortality was 1.8 times higher in residents at risk of malnutrition (Adjusted HR 1.82, 95% CI 1.19-2.79, P =0.006). CONCLUSIONS Our results provide strong evidence that risk of malnutrition can predict not only cognitive and functional decline but also risk of all-cause mortality in older men living in a veteran retirement's community. Further longitudinal studies are needed to explore the causal relationship among nutrition, clinical outcomes, and the effect of an intervention for malnutrition.
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Affiliation(s)
- Y-H Hsu
- Chih-Kuang Liang, Address: Center for Geriatrics and Gerontology, Kaohsiung Veterans General Hospital, No. 386, Dazhong 1st Rd., Zuoying Dist., Kaohsiung City 81362, Taiwan (R.O.C.), Phone: 886-7-3422526, E-mail:
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Chen P, Pai WW, Chan YH, Madhavan V, Chou MY, Mo SK, Fedorov AV, Chiang TC. Unique Gap Structure and Symmetry of the Charge Density Wave in Single-Layer VSe_{2}. Phys Rev Lett 2018; 121:196402. [PMID: 30468619 DOI: 10.1103/physrevlett.121.196402] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 06/09/2023]
Abstract
Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these single layers are generally a planar projection of the corresponding bulk CDWs because of the quasi-two-dimensional nature of TMDCs; a different CDW symmetry is unexpected. We report herein the successful creation of pristine single-layer VSe_{2}, which shows a (sqrt[7]×sqrt[3]) CDW in contrast to the (4×4) CDW for the layers in bulk VSe_{2}. Angle-resolved photoemission spectroscopy from the single layer shows a sizable (sqrt[7]×sqrt[3]) CDW gap of ∼100 meV at the zone boundary, a 220 K CDW transition temperature twice the bulk value, and no ferromagnetic exchange splitting as predicted by theory. This robust CDW with an exotic broken symmetry as the ground state is explained via a first-principles analysis. The results illustrate a unique CDW phenomenon in the two-dimensional limit.
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Affiliation(s)
- P Chen
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Woei Wu Pai
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Y-H Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - V Madhavan
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA
| | - M Y Chou
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A-V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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Chen P, Pai WW, Chan YH, Sun WL, Xu CZ, Lin DS, Chou MY, Fedorov AV, Chiang TC. Large quantum-spin-Hall gap in single-layer 1T' WSe 2. Nat Commun 2018; 9:2003. [PMID: 29784909 PMCID: PMC5962594 DOI: 10.1038/s41467-018-04395-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/24/2018] [Indexed: 12/04/2022] Open
Abstract
Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe2 single layer with the 1T′ structure that does not exist in the bulk form of WSe2. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1T′ layer and an in-gap edge state located near the layer boundary. The system′s 2D TI characters are confirmed by first-principles calculations. The observed gap diminishes with doping by Rb adsorption, ultimately leading to an insulator–semimetal transition. The discovery of this large-gap 2D TI with a tunable band gap opens up opportunities for developing advanced nanoscale systems and quantum devices. The current known two-dimensional topological insulators with small band gaps limit the potential for room temperature applications. Here, Chen et al. observe a sizable gap of 129 meV in a 1T'-WSe2 single layer grown on bilayer graphene with in-gap edge state near the layer boundary.
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Affiliation(s)
- P Chen
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL, 61801-3080, USA. .,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, IL, 61801-2902, USA. .,Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Woei Wu Pai
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan.,Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.,Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, 6 10617, Taiwan
| | - Y-H Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - W-L Sun
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - C-Z Xu
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL, 61801-3080, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, IL, 61801-2902, USA
| | - D-S Lin
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - M Y Chou
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.,Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, 6 10617, Taiwan.,School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - A-V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL, 61801-3080, USA. .,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, IL, 61801-2902, USA. .,Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
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Chi MJ, Liang CK, Lee WJ, Peng LN, Chou MY, Chen LK. Association of New-Onset Diabetes Mellitus in Older People and Mortality in Taiwan: A 10-Year Nationwide Population-Based Study. J Nutr Health Aging 2017; 21:227-232. [PMID: 28112781 DOI: 10.1007/s12603-016-0751-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Older patients with diabetes mellitus are at a higher risk of developing diabetic macro- and micro-vascular complications and cardiovascular diseases than younger diabetes mellitus patients. However, older diabetes mellitus patients are very heterogeneous in their clinical characteristics, diabetes mellitus-related complications and age at disease onset. This study aimed to evaluate the all-cause mortality rates and adverse health outcomes among older adults with new-onset diabetes mellitus through a nationwide population-based study. DESIGN A retrospective cohort study. SETTING 2001-2011 data of the National Health Insurance database. POPULATION Nationally representative sample of Taiwanese adults aged 65 years and older with propensity score-matched controls. MAIN OUTCOME MEASURES All-cause mortality and adverse health outcomes. RESULTS During the study period, 45.3% of patients in the diabetes mellitus cohort and 38.8% in the non-diabetes mellitus cohort died. The adjusted relative risk for mortality in the diabetes mellitus cohort compared to the non-diabetes mellitus cohort was 1.23 (95% Confidence Interval [CI]=1.16-1.30) for males and 1.27 (95%CI=1.19-1.35) for females. During the follow-up period, 8.9% of the diabetes mellitus cohort and 5.8% of the non-diabetes mellitus cohort developed cardiovascular diseases; the diabetes mellitus cohort had an adjusted relative risk of cardiovascular complications compared to the non-diabetes mellitus cohort of 1.54 (95%CI=1.36-1.75) for men and 1.70 (95%CI=1.43-2.02) for women. The adjusted relative risk of mortality in the patients with hypoglycemia compared to non-hypoglycemia patients in the diabetes mellitus cohort was 2.33 (95%CI=1.81-3.01) for men and 2.73 (95%CI=2.10-3.52) for women after adjustment for age, Charlson comorbidity index, acute coronary syndrome, respiratory disease, cancer, infectious disease and nervous system disease at baseline. CONCLUSIONS New-onset diabetes in older adults is associated with an increased risk of mortality, and hypoglycemia is an important marker of this association. Individualized care plans stratified by age at onset, duration of disease, comorbidity and functional status, as well as hypoglycemia avoidance, would benefit the management of diabetes in older adults.
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Affiliation(s)
- M-J Chi
- Prof. Liang-Kung Chen, Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan, TEL: +886-2-28757830, FAX:+886-2-28757711,
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Chen P, Chan YH, Wong MH, Fang XY, Chou MY, Mo SK, Hussain Z, Fedorov AV, Chiang TC. Dimensional Effects on the Charge Density Waves in Ultrathin Films of TiSe 2. Nano Lett 2016; 16:6331-6336. [PMID: 27648493 DOI: 10.1021/acs.nanolett.6b02710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Charge density wave (CDW) formation in solids is a critical phenomenon involving the collective reorganization of the electrons and atoms in the system into a wave structure, and it is expected to be sensitive to the geometric constraint of the system at the nanoscale. Here, we study the CDW transition in TiSe2, a quasi-two-dimensional layered material, to determine the effects of quantum confinement and changing dimensions in films ranging from a single layer to multilayers. Of key interest is the characteristic length scale for the transformation from a two-dimensional case to the three-dimensional limit. Angle-resolved photoemission spectroscopy (ARPES) measurements of films with thicknesses up to six layers reveal substantial variations in the energy structure of discrete quantum well states; however, the temperature-dependent band gap renormalization converges at just three layers. The results indicate a layer-dependent mixture of two transition temperatures and a very-short-range CDW interaction within a three-dimensional framework.
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Affiliation(s)
- P Chen
- Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801-3080, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, United States
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Y-H Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
| | - M-H Wong
- Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801-3080, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, United States
| | - X-Y Fang
- Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801-3080, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, United States
| | - M Y Chou
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
- Department of Physics, National Taiwan University , Taipei 10617, Taiwan
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - A-V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801-3080, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, United States
- Department of Physics, National Taiwan University , Taipei 10617, Taiwan
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Alikhani M, Alyami B, Lee IS, Almoammar S, Vongthongleur T, Alikhani M, Alansari S, Sangsuwon C, Chou MY, Khoo E, Boskey A, Teixeira CC. Saturation of the biological response to orthodontic forces and its effect on the rate of tooth movement. Orthod Craniofac Res 2016; 18 Suppl 1:8-17. [PMID: 25865529 DOI: 10.1111/ocr.12090] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2014] [Indexed: 01/16/2023]
Abstract
OBJECTIVES Investigate the expression and activity of inflammatory markers in response to different magnitudes of orthodontic forces and correlate this response with other molecular and cellular events during orthodontic tooth movement. SETTING AND SAMPLE POPULATION CTOR Laboratory; 245 Sprague Dawley male rats. METHODS AND MATERIALS Control, sham, and 5 different experimental groups received different magnitudes of force on the right maxillary first molar using a coil spring. In the sham group, the spring was not activated. Control group did not receive any appliance. At days 1, 3, 7, 14, and 28, the maxillae were collected for RNA and protein analysis, immunohistochemistry, and micro-CT. RESULTS There was a linear relation between the force and the level of cytokine expression at lower magnitudes of force. Higher magnitudes of force did not increase the expression of cytokines. Activity of CCL2, CCL5, IL-1, TNF-α, RANKL, and number of osteoclasts reached a saturation point in response to higher magnitudes of force, with unchanged rate of tooth movement. CONCLUSION After a certain magnitude of force, there is a saturation in the biological response, and higher forces do not increase inflammatory markers, osteoclasts, nor the amount of tooth movement. Therefore, higher forces to accelerate the rate of tooth movement are not justified.
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Affiliation(s)
- M Alikhani
- Consortium for Translational Orthodontic Research, New York University College of Dentistry, New York, NY, USA; Department of Orthodontics, New York University College of Dentistry, New York, NY, USA; Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
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11
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Chen P, Chan YH, Fang XY, Zhang Y, Chou MY, Mo SK, Hussain Z, Fedorov AV, Chiang TC. Charge density wave transition in single-layer titanium diselenide. Nat Commun 2015; 6:8943. [PMID: 26568512 PMCID: PMC4660365 DOI: 10.1038/ncomms9943] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/19/2015] [Indexed: 11/18/2022] Open
Abstract
A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene—a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The observed Bardeen-Cooper-Schrieffer (BCS) behaviour of the gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk. Single molecular layers of TiSe2 are promising for advanced electronic applications, and it is therefore important to characterize their phases. Here, the authors use ARPES to detect a charge density wave transition without Fermi surface nesting and that takes place at a temperature higher than in bulk.
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Affiliation(s)
- P Chen
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA.,Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Y-H Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - X-Y Fang
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA
| | - Y Zhang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.,Stanford Institute of Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Y Chou
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.,School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.,Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A-V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA.,Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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12
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Abstract
The low-energy quasiparticles in graphene can be described by a Dirac-Weyl Hamiltonian for massless fermions, hence graphene has been proposed to be an effective medium to study exotic phenomena originally predicted for relativistic particle physics, such as Klein tunneling and Zitterbewegung. In this work, we show that another important particle-physics phenomenon, the neutrino oscillation, can be studied and observed in a particular graphene system, namely, twisted bilayer graphene. It has been found that graphene layers grown epitaxially on SiC or by the chemical vapor deposition method on metal substrates display a stacking pattern with adjacent layers rotated by an angle with respect to each other. The quasiparticle states in two distinct graphene layers act as neutrinos with two flavors, and the interlayer interaction between them induces an appreciable coupling between these two "flavors" of massless fermions, leading to neutrino-like oscillations. In addition, our calculation shows that anisotropic transport properties manifest in a specific energy window, which is accessible experimentally in twisted bilayer graphene. Combining two graphene layers enables us to probe the rich physics involving multiple interacting Dirac fermions.
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Affiliation(s)
- Lede Xian
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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13
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Berrut G, Andrieu S, Araujo de Carvalho I, Baeyens JP, Bergman H, Cassim B, Cerreta F, Cesari M, Cha HB, Chen LK, Cherubini A, Chou MY, Cruz-Jentoft AJ, De Decker L, Du P, Forette B, Forette F, Franco A, Guimaraes R, Guttierrez-Robledo LM, Jauregui J, Khavinson V, Lee WJ, Peng LN, Perret-Guillaume C, Petrovic M, Retornaz F, Rockwood K, Rodriguez-Manas L, Sieber C, Spatharakis G, Theou O, Topinkova E, Vellas B, Benetos A. Promoting access to innovation for frail old persons. IAGG (International Association of Gerontology and Geriatrics), WHO (World Health Organization) and SFGG (Société Française de Gériatrie et de Gérontologie) Workshop--Athens January 20-21, 2012. J Nutr Health Aging 2013; 17:688-93. [PMID: 24097023 DOI: 10.1007/s12603-013-0039-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
UNLABELLED Frailty tends to be considered as a major risk for adverse outcomes in older persons, but some important aspects remain matter of debate. OBJECTIVES The purpose of this paper is to present expert's positions on the main aspects of the frailty syndrome in the older persons. PARTICIPANTS Workshop organized by International Association of Gerontology and Geriatrics (IAGG), World Health Organization (WHO) and Société Française de Gériatrie et de Gérontologie (SFGG). RESULTS Frailty is widely recognized as an important risk factor for adverse health outcomes in older persons. This can be of particular value in evaluating non-disabled older persons with chronic diseases but today no operational definition has been established. Nutritional status, mobility, activity, strength, endurance, cognition, and mood have been proposed as markers of frailty. Another approach calculates a multidimensional score ranging from "very fit" to "severely frail", but it is difficult to apply into the medical practice. Frailty appears to be secondary to multiple conditions using multiple pathways leading to a vulnerability to a stressor. Biological (inflammation, loss of hormones), clinical (sarcopenia, osteoporosis etc.), as well as social factors (isolation, financial situation) are involved in the vulnerability process. In clinical practice, detection of frailty is of major interest in oncology because of the high prevalence of cancer in older persons and the bad tolerance of the drug therapies. Presence of frailty should also be taken into account in the definition of the cardiovascular risks in the older population. The experts of the workshop have listed the points reached an agreement and those must to be a priority for improving understanding and use of frailty syndrome in practice. CONCLUSION Frailty in older adults is a syndrome corresponding to a vulnerability to a stressor. Diagnostic tools have been developed but none can integrate at the same time the large spectrum of factors and the simplicity asked by the clinical practice. An agreement with an international common definition is necessary to develop screening and to reduce the morbidity in older persons.
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Affiliation(s)
- G Berrut
- Pr Athanase Benetos, MD, PhD, Département de Médecine Gériatrique, CHU de Nancy, Avenue de Bourgogne, BP 217, 54511 Vandoeuvre-les-Nancy, France,
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14
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Abstract
We have performed calculations of adsorption energetics on the graphene surface using the state-of-the-art diffusion quantum Monte Carlo method. Two types of configurations are considered in this work: the adsorption of a single O, F, or H atom on the graphene surface and the H-saturated graphene system (graphane). The adsorption energies are compared with those obtained from density functional theory with various exchange-correlation functionals. The results indicate that the approximate exchange-correlation functionals significantly overestimate the binding of O and F atoms on graphene, although the preferred adsorption sites are consistent. The energy errors are much less for atomic hydrogen adsorbed on the surface. We also find that a single O or H atom on graphene has a higher energy than in the molecular state, while the adsorption of a single F atom is preferred over the gas phase. In addition, the energetics of graphane is reported. The calculated equilibrium lattice constant turns out to be larger than that of graphene, at variance with a recent experimental suggestion.
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Affiliation(s)
- C R Hsing
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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15
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Abstract
The Hofstadter butterfly spectrum for Landau levels in a two-dimensional periodic lattice is a rare example exhibiting fractal properties in a truly quantum system. However, the observation of this physical phenomenon in a conventional material will require a magnetic field strength several orders of magnitude larger than what can be produced in a modern laboratory. It turns out that for a specific range of rotational angles twisted bilayer graphene serves as a special system with a fractal energy spectrum under laboratory accessible magnetic field strengths. This unique feature arises from an intriguing electronic structure induced by the interlayer coupling. Using a recursive tight-binding method, we systematically map out the spectra of these Landau levels as a function of the rotational angle. Our results give a complete description of LLs in twisted bilayer graphene for both commensurate and incommensurate rotational angles and provide quantitative predictions of magnetic field strengths for observing the fractal spectra in these graphene systems.
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Affiliation(s)
- Z F Wang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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16
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Abstract
Graphene is believed to be an excellent candidate material for next-generation electronic devices. However, one needs to take into account the nontrivial effect of metal contacts in order to precisely control the charge injection and extraction processes. We have performed transport calculations for graphene junctions with wetting metal leads (metal leads that bind covalently to graphene) using nonequilibrium Green's functions and density functional theory. Quantitative information is provided on the increased resistance with respect to ideal contacts and on the statistics of current fluctuations. We find that charge transport through the studied two-terminal graphene junction with Ti contacts is pseudo-diffusive up to surprisingly high energies.
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Affiliation(s)
- Salvador Barraza-Lopez
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
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17
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Liu CM, Yeh CJ, Yu CC, Chou MY, Lin CH, Wei LH, Lin CW, Yang SF, Chien MH. Impact of interleukin-8 gene polymorphisms and environmental factors on oral cancer susceptibility in Taiwan. Oral Dis 2011; 18:307-14. [PMID: 22151543 DOI: 10.1111/j.1601-0825.2011.01882.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVES Interleukin-8 (IL-8), which is an angiogenic chemokine with a high expression level in tumor tissues, plays important roles in developing many human malignancies including oral squamous cell carcinoma (OSCC). This study was designed to examine the association of IL-8 gene polymorphisms with the susceptibility and clinicopathological characteristics of OSCC. METHODS A total of 270 patients with OSCC and 350 healthy control subjects were recruited. Four single nucleotide polymorphisms (SNPs) of IL-8 genes were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping analysis. RESULTS Results showed that four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) were not associated with oral cancer susceptibility as well as clinicopathological parameters. But among 345 smokers, IL-8 polymorphisms carriers with betel quid chewing were found to have a 17.41- to 23.14-fold risk to have oral cancer compared to IL-8 wild-type carriers without betel quid chewing. Among 262 betel quid chewers, IL-8 polymorphisms carriers with smoking have a 10.54- to 20.44-fold risk to have oral cancer compared to those who carried wild type without smoking. CONCLUSIONS Our results suggest that the combination of IL-8 gene polymorphisms and environmental carcinogens might be highly related to the risk of oral cancer.
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Affiliation(s)
- C-M Liu
- School of Dentistry, Chung Shan Medical University, Taichung, Taiwan
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18
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Abstract
We have performed first-principles calculations to study the lattice vibrational modes and their Raman activities in silicon nanowires (SiNWs). Two types of characteristic vibrational modes are examined: high-frequency optical modes and low-frequency confined modes. Their frequencies have opposite size dependence with a red shift for the optical modes and a blue shift for the confined modes as the diameter of SiNWs decreases. In addition, our calculations show that these vibrational modes can be detected by Raman scattering measurements, providing an efficient way to estimate the size of SiNWs.
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Affiliation(s)
- Li Yang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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19
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Abstract
AIM To evaluate the mechanisms of cytotoxicity of chlorhexidine (CHX) in human osteoblastic cells in vitro. METHODOLOGY Cytotoxicity, cell proliferation and collagen synthesis assays were performed to elucidate the toxic effects of CHX on the human osteoblastic cell line U2OS. To determine whether glutathione (GSH) levels were important in the cytotoxicity of CHX, cells were pre-treated with 2-oxothiazolidine-4-carboxylic acid (OTZ) to boost GSH levels or buthionine sulfoximine (BSO) to deplete GSH. RESULTS CHX demonstrated a cytotoxic effect to U2OS cells in a dose-dependent manner (P < 0.05). The 50% inhibition concentration of CHX was approximately 0.005%. CHX also inhibited cell proliferation and collagen synthesis (P < 0.05). The addition of OTZ acted as a protective effect on the CHX-induced cytotoxicity (P < 0.05). In contrast, the addition of BSO enhanced the CHX-induced cytotoxicity (P < 0.05). CONCLUSIONS The levels of CHX tested inhibited cell growth, proliferation and collagen synthesis on U2OS cells. CHX has significant potential for periapical toxicity. GSH depletion might be one of the mechanisms underlying CHX cytotoxicity.
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Affiliation(s)
- T-H Lee
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
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20
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Lee CM, Lee RCH, Ruan WY, Chou MY. Energy spectra of a single-electron magnetic dot using the massless Dirac-Weyl equation. J Phys Condens Matter 2010; 22:355501. [PMID: 21403291 DOI: 10.1088/0953-8984/22/35/355501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper, we study the low-lying energy spectra of a two-dimensional (2D) graphene-based magnetic dot in a perpendicular and radially inhomogeneous magnetic field with the use of the massless Dirac-Weyl equation. Numerical calculations are performed using 2D harmonic basis states for direct diagonalization. Effects of both the dot size and the magnetic field on the low-lying energy spectra are discussed.
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Affiliation(s)
- C M Lee
- Newtech Computer (HK) Ltd, Unit P, 6/F., Kaiser Estate, Phase 3, 11 Hok Yuen Street, Hunghom, Hong Kong.
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21
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Barraza-Lopez S, Vanević M, Kindermann M, Chou MY. Effects of metallic contacts on electron transport through graphene. Phys Rev Lett 2010; 104:076807. [PMID: 20366907 DOI: 10.1103/physrevlett.104.076807] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Indexed: 05/29/2023]
Abstract
We report on a first-principles study of the conductance through graphene suspended between Al contacts as a function of junction length, width, and orientation. The charge transfer at the leads and into the freestanding section gives rise to an electron-hole asymmetry in the conductance and in sufficiently long junctions induces two conductance minima at the energies of the Dirac points for suspended and clamped regions, respectively. We obtain the potential profile along a junction caused by doping and provide parameters for effective model calculations of the junction conductance with weakly interacting metallic leads.
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22
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Jean SS, Hsueh PR, Lee WS, Chang HT, Chou MY, Chen IS, Wang JH, Lin CF, Shyr JM, Ko WC, Wu JJ, Liu YC, Huang WK, Teng LJ, Liu CY. In vitro activities of doripenem and other carbapenems against clinically important bacteria isolated in intensive care units: nationwide data from the SMART Programme. Eur J Clin Microbiol Infect Dis 2010; 29:471-5. [PMID: 20108018 DOI: 10.1007/s10096-009-0866-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 12/21/2009] [Indexed: 11/28/2022]
Abstract
This nationwide surveillance of clinically important bacteria from the intensive care units (ICUs) of major teaching hospitals throughout Taiwan investigated the susceptibilities to doripenem and other comparator carbapenems from September through November 2005. Minimum inhibitory concentrations (MICs) were determined for 1,311 clinical isolates using the broth microdilution method according to Clinical and Laboratory Standards Institute (CLSI) 2005 guidelines. Doripenem showed similar (within four-fold difference of MICs) in vitro activity to meropenem for Enterobacteriaceae and probably comparable activity to meropenem against important nosocomial non-fermentative Gram-negative bacilli (NFGNBs), including Pseudomonas aeruginosa, Acinetobacter baumannii and Burkholderia cepacia. Among the four carbapenems analysed, doripenem and meropenem exhibited better in vitro activity than imipenem or ertapenem against extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli isolates. However, the meropenem MIC(90) against ESBL-producing K. pneumoniae isolates was 2 microg/ml. Besides, doripenem with the MIC(90) of 0.5 microg/ml to Streptococcus pneumoniae possibly suggested its potential therapeutic effect regarding community-acquired pneumonia. Because of the heavy resistance burden in Taiwan, closely monitoring the evolutionary trend of carbapenem susceptibilities against clinically important pathogens is crucial in the future.
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Affiliation(s)
- S-S Jean
- Department of Intensive Care Units, Min-Sheng General Hospital, Taoyuan County, Taiwan
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Abstract
We have systematically investigated the effect of oxidation on the structural and electronic properties of graphene based on first-principles calculations. Energetically favorable atomic configurations and building blocks are identified, which contain epoxide and hydroxyl groups in close proximity with each other. Different arrangements of these units yield a local-density approximation band gap over a range of a few eV. These results suggest the possibility of creating and tuning the band gap in graphene by varying the oxidation level and the relative amount of epoxide and hydroxyl functional groups on the surface.
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Affiliation(s)
- Jia-An Yan
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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Chou MY, Yan D, Jafarov T, Everett ET. Modulation of murine bone marrow-derived CFU-F and CFU-OB by in vivo bisphosphonate and fluoride treatments. Orthod Craniofac Res 2009; 12:141-7. [PMID: 19419457 DOI: 10.1111/j.1601-6343.2009.01447.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Bisphosphonates (BPN) have actions on a variety of cell types including: osteoclasts, osteoblasts, osteocytes, and endothelial cells. The objectives of this report are to review the current state of understanding of the effects of BPNs on orthodontic tooth movement and to provide evidence on BPN's in vivo effects on bone marrow-derived osteoprogenitor cells. MATERIAL AND METHODS Mice from the C3H/HeJ (C3H), C57BL/6J (B6), FVB/NJ (FVB), and BALB/cByJ (BALB) strains were treated for 3 weeks with 0, 3, 30, or 150 mcg/kg/week alendronate (ALN) administered subcutaneous alone or in combination with 50 ppm fluoride (F). Bone marrow cells were harvested and subjected to in vitro colony-forming unit fibroblast (CFU-F) and colony-forming unit osteoblasts (CFU-OB) assays. RESULTS Baseline differences in CFU-F, CFU-OB/ALP+, and CFU-OB/total were observed among the four strains. Strain-specific responses to ALN and F treatments were observed for CFU-F, CFU-OB/ALP+, and CFU-OB/total. F treatment alone resulted in decreases in CFU-F (p = 0.013), CFU-OB/ALP+ (p = 0.005), and CFU-OB/total (p = 0.003) in the C3H strain. CFU-F (p = 0.036) were decreased by F in the B6 strain. No significant (NS) effects of F were observed for FVB and BALB. ALN treatment resulted in a significant decrease in CFU-F (p = 0.0014) and CFU-OB/total (p = 0.028) in C3H only. ALN treatment had NS effect on CFU-OB/ALP+ in all four strains. CONCLUSION Genetic factors appear to play a role in ALN's effects on CFU-F and CFU-OB/total but not on CFU-OB/ALP+.
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Affiliation(s)
- M-Y Chou
- Department of Prosthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7450, USA
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25
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Miller T, Chou MY, Chiang TC. Phase relations associated with one-dimensional shell effects in thin metal films. Phys Rev Lett 2009; 102:236803. [PMID: 19658957 DOI: 10.1103/physrevlett.102.236803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2009] [Indexed: 05/28/2023]
Abstract
The physical and chemical properties of thin metal films show damped oscillations as a function of film thickness (one-dimensional shell effects). While the oscillation period, determined by subband crossings of the Fermi level, is the same for all properties, the phases can be different. Specifically, oscillations in the work function and surface energy are offset by 1/4 of a period. For Pb(111) films, this offset is approximately 0.18 monolayers, a seemingly very small effect. However, aliasing caused by the discrete atomic layer structure leads to striking out-of-phase beating patterns displayed by these two quantities.
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Affiliation(s)
- T Miller
- Department of Physics, University of Illinois, Urbana, Illinois 61801-3080, USA
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26
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Chou MY, Hartvigsen K, Hansen LF, Fogelstrand L, Shaw PX, Boullier A, Binder CJ, Witztum JL. Oxidation-specific epitopes are important targets of innate immunity. J Intern Med 2008; 263:479-88. [PMID: 18410591 DOI: 10.1111/j.1365-2796.2008.01968.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During the oxidation of LDL, a central pathophysiological component of atherogenesis, a wide variety of chemical and physical changes occur leading to the generation of oxidation-specific neoepitopes. These epitopes are not only immunogenic, leading to adaptive humoral responses, but are also a prominent target of multiple arcs of innate immunity. The pattern recognition receptors (PRRs) of innate immunity are germ line encoded, conserved by natural selection, and bind to pathogen-associated molecular patterns (PAMPs) common on multiple structures. However, it is not intuitive as to why they should recognize oxidation-specific neoepitopes. Yet it is clear that multiple macrophage scavenger receptors, which are classic PRRs, recognize oxidation-specific epitopes, such as those found on oxidized LDL (OxLDL). Other innate proteins, such as C-reactive protein, also bind to OxLDL. Natural antibodies (NAbs), the humoral arc of innate immunity, provide a nonredundant role in the first line of defence against pathogens, but are also believed to provide important homeostatic house-keeping functions against self-antigens. Our work demonstrates that oxidation-specific epitopes, as found on OxLDL, are a major target of NAbs. In this review, we will discuss the specific example of the prototypic NAb T15/E06, which is increased in atherosclerotic mice and mediates atheroprotection, and discuss the potential role of NAbs in atherogenesis, and in inflammation in general. We also review data that oxidation-specific epitopes are generated whenever cells undergo programmed cell death, forming a common set of PAMPs recognized by oxidation-specific PRRs on macrophages, NAbs and innate proteins. We present the hypothesis that oxidation-specific epitopes on apoptotic cells exerted evolutionary pressure for the conservation of these PRRs and also serve to maintain the expansion of a substantial proportion of NAbs directed to these stress-induced self-antigens.
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Affiliation(s)
- M-Y Chou
- Department of Medicine, University of California at San Diego, La Jolla, CA, USA
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27
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Eom D, Qin S, Chou MY, Shih CK. Persistent superconductivity in ultrathin Pb films: a scanning tunneling spectroscopy study. Phys Rev Lett 2006; 96:027005. [PMID: 16486621 DOI: 10.1103/physrevlett.96.027005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2005] [Indexed: 05/06/2023]
Abstract
By using a low temperature scanning tunneling microscope we have probed the superconducting energy gap of epitaxially grown Pb films as a function of the layer thickness in an ultrathin regime (5-18 ML). The layer-dependent energy gap and transition temperature (Tc) show persistent quantum oscillations down to the lowest thickness without any sign of suppression. Moreover, by comparison with the quantum-well states measured above Tc and the theoretical calculations, we found that the Tc oscillation correlates directly with the density of states oscillation at E(F) . The oscillation is manifested by the phase matching of the Fermi wavelength and the layer thickness, resulting in a bilayer periodicity modulated by a longer wavelength quantum beat.
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Affiliation(s)
- Daejin Eom
- Department of Physics and Center for Nano and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712, USA
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Huang FM, Chen YJ, Chou MY, Chang YC. Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by Porphyromonas endodontalis in human pulp cells. Int Endod J 2005; 38:860-5. [PMID: 16343111 DOI: 10.1111/j.1365-2591.2005.01026.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM To investigate the tissue type plasminogen activator (t-PA) activity in human pulp cells stimulated with Porphyromonas endodontalis (P. endodontalis) in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002. METHODOLOGY The supernatants of P. endodontalis were used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search for possible signal transduction pathways, SB203580, U0126 and LY294002 were added to test how they modulated the t-PA activity. RESULTS The main casein secreted by human pulp cells migrated at 70 kDa and represented t-PA. Secretion of t-PA was found to be stimulated with P. endodontalis during 2-day cultured period (P < 0.05). From the results of casein zymography and ELISA, SB203580 and U0126 significantly reduced the P. endodontalis stimulated t-PA production respectively (P < 0.05). However, LY294002 lacked the ability to change the P. endodontalis stimulated t-PA production (P > 0.05). CONCLUSIONS Porphyromonas endodontalis enhances t-PA production in human pulp cells, and the signal transduction pathways p38 and MEK are involved in the inhibition of t-PA.
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Affiliation(s)
- F-M Huang
- School of Dentistry, Chung Shan Medical University, Taichung, Taiwan
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Abstract
AIM To compare tissue-type plasminogen activator (t-PA) expression in normal human pulp and inflamed human pulp tissue specimens. METHODOLOGY Thirty pulpal tissue specimens (13 normal and 17 inflamed pulps) were obtained from extracted third molars. The levels of t-PA between normal pulp and inflamed pulp tissues were compared using the quantitative reverse-transcriptase polymerase chain reaction analysis. In addition, immunohistochemistry was used to identify the in situ localization of t-PA expression in pulp specimens. Wilcoxon-Mann-Whitney rank sum test was applied for the statistical analysis of the results. RESULTS t-PA mRNA gene was found more in inflamed pulps when compared with normal pulp tissue (P<0.05). The results from immunohistochemistry demonstrated that t-PA expression was significantly higher in the inflamed pulp (P=0.025). t-PA stain was detected in the fibroblasts, inflammatory infiltrates and endothelial cells. CONCLUSIONS t-PA expression was significantly higher in inflamed pulp tissue. t-PA may play an important role in the pathogenesis of pulpal inflammation.
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Affiliation(s)
- F-M Huang
- Oral Medicine Center, Chung Shan Medical University Hospital, Taichung, Taiwan
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Yvon K, Renaudin G, Wei CM, Chou MY. Hydrogenation-induced insulating state in the intermetallic compound LaMg2Ni. Phys Rev Lett 2005; 94:066403. [PMID: 15783759 DOI: 10.1103/physrevlett.94.066403] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Indexed: 05/24/2023]
Abstract
Hydrogenation-induced metal-semiconductor transitions usually occur in simple systems based on rare earths and/or magnesium, accompanied by major reconstructions of the metal host (atom shifts >2 A). We report on the first such transition in a quaternary system based on a transition element. Metallic LaMg2Ni absorbs hydrogen near ambient conditions, forming the nonmetallic hydride LaMg2NiH7 which has a nearly unchanged metal host structure (atom shifts <0.7 A). The transition is induced by a charge transfer of conduction electrons into tetrahedral [NiH4]4- complexes having closed-shell electron configurations.
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Affiliation(s)
- K Yvon
- Laboratory of Crystallography, University of Geneva, 1211 Geneva 4, Switzerland
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Huang CR, Lin SS, Chou MY, Ho CC, Wang L, Lee YL, Chen CS, Yang CC. Demonstration of different modes of cell death upon herpes simplex virus 1 infection in different types of oral cells. Acta Virol 2005; 49:7-15. [PMID: 15929393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The effects of Herpes simplex virus 1 (HSV-1) infection on five different types of oral cancerous cells (neck metastasis of gingival carcinoma (GNM) cells and tongue squamous cells of carcinoma (TSCCa) and non-cancerous cells (buccal mucosal fibroblasts (BF), gingival fibroblasts (GF), oral submucosal fibrosis cells (OSF)) and one type of non-oral cancerous cells (KB cells) were investigated. In HSV-1-infected cells the cell viability, CPE, viral antigens accumulation, caspase-3 activity, annexin V binding and DNA fragmentation were estimated. Three different forms or pathways of cell death were considered: apoptosis (the presence or rise of caspase-3 activity, DNA fragmentation and annexin V binding), slow cell death (the presence or rise of DNA fragmentation, the absence or decline of caspase-3 activity and annexin V binding), and necrosis (the absence of decline of caspase-3 activity, DNA fragmentation and annexin V binding). The viability of all cell types, except for KB cells, was reduced by the infection. CPE and viral antigens data demonstrated that all six types of cells could be infected with HSV-1. Upon HSV-1 infection there occurred (i) a classical apoptosis in GF cells, (ii) apoptosis in the early phase of infection and necrosis in the late phase of infection in GNM and TSCCa cells, (iii) slow cell death followed by necrosis in BF and OSF cells (however, these cells showed a different type of CPE), (iv) a classical slow cell death in KB cells. It is hypothesized that HSV-1 infection has a potential to induce several distinct pathways leading to cell death or several forms of cell death. Moreover, more than one pathway may be involved in the death of particular cell type. As HSV-1 was demonstrated to infect different oral and non-oral cells and cause different pathways or forms of cell death, the safety of using HSV-1 as a vector for gene therapy should be re-considered.
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Affiliation(s)
- C R Huang
- Institute of Immunology, Chung Shan Medical University Hospital, Taichung, Taiwan, Republic of China
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Abstract
The atomic geometry, electronic structure, and magnetic moment of 4d transition-metal clusters with 13 atoms are studied by pseudopotential density-functional calculations. We find a new buckled biplanar structure with a C(2v) symmetry stabilized by enhanced s-d hybridization. It has a lower energy than the close-packed icosahedral or cuboctahedral structure for elements with more than half-filled d shells. The magnetic moments of this buckled biplanar structure are found to be smaller than those of the icosahedral structure and closer to available experimental results.
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Affiliation(s)
- C M Chang
- Department of Physics, National Dong Hwa University, Hualien 974, Taiwan, Republic of China
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Upton MH, Wei CM, Chou MY, Miller T, Chiang TC. Thermal stability and electronic structure of atomically uniform Pb films on Si(111). Phys Rev Lett 2004; 93:026802. [PMID: 15323937 DOI: 10.1103/physrevlett.93.026802] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Indexed: 05/24/2023]
Abstract
Atomically uniform Pb films are successfully prepared on Si(111), despite a large lattice mismatch. Angle-resolved photoemission measurements of the electronic structure show layer-resolved quantum well states which can be correlated with dramatic variations in thermal stability. The odd film thicknesses N = 5, 7, and 9 monolayers show sharp quantum well states. The even film thicknesses N = 6 and 8 do not, but are much more stable than the odd film thicknesses. This correlation is discussed in terms of a total energy calculation and Friedel-like oscillations in properties.
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Affiliation(s)
- M H Upton
- Frederick Seitz Materials Research Laboratory, Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-2902, USA
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Abstract
We investigate the structural, electronic, and optical properties of hydrogen-passivated silicon nanowires along [110] and [111] directions with diameter d up to 4.2 nm from first principles. The size and orientation dependence of the band gap is investigated and the local-density gap is corrected with the GW approximation. Quantum confinement becomes significant for d<2.2 nm, where the dielectric function exhibits strong anisotropy and new low-energy absorption peaks start to appear in the imaginary part of the dielectric function for polarization along the wire axis.
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Affiliation(s)
- Xinyuan Zhao
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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Abstract
The objective of this study was to determine the cytocompatibility of three different extracts of gingival retraction cords and to compare the cytotoxic effect of these materials on human gingival fibroblasts. Gingival retraction cords impregnated with aluminium sulphate (Gingi-Aid), dl-adrenaline HCl (Gingi-Pak) and non-drug-impregnated cord (Gingi-Plain) were eluted with culture medium for 10 min and 24 h. Cytotoxicity was judged using a tetrazolium bromide reduction assay. Our data demonstrated that gingival retraction cords applied alone almost completely inhibited cell viability (P < 0.05). In addition, the results also showed that the eluates from aluminium sulphate-impregnated cord, dl-adrenaline HCl-impregnated cord and non-drug-impregnated cord were cytotoxic to primary human gingival fibroblast cultures (P < 0.05). The cell viability of incubation of gingival fibroblasts containing 10-min eluates of aluminium sulphate, dl-adrenaline HCl and non-drug-impregnated cord was 61, 21 and 70%, respectively. The cell viability of incubation of gingival fibroblasts containing 24 h eluates of aluminium sulphate, dl-adrenaline HCl and non-drug-impregnated cord was 68, 58 and 72%, respectively. It was found that dl-adrenaline HCl-impregnated gingival retraction cord was the most toxic gingival retraction cord among the materials tested in all cultures (P < 0.05). The cytotoxicity decreased in an order of dl-adrenaline HCl-impregnated cord > aluminium sulphate-impregnated cord > non-drug-impregnated cord. The extent or degree of the cytotoxicity depended on the materials tested. Gingival retraction cords have significant potential for gingival toxicity. Careful management of gingiva retraction cords would lower the risk of potential gingival tissue damage during clinical application procedure and thus increase the success of prosthodontic procedures.
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Affiliation(s)
- C-M Liu
- Department of Periodontics, Chung Shan Medical University Hospital, Taichung, Taiwan
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Abstract
BACKGROUND Nonsteroidal anti-inflammatory drugs (NSAIDs) such as acetylsalicylic acid (ASA, aspirin) are well known chemotherapeutic agents of cancers; however, the signalling molecules involved remain unclear. The aim of this study was to investigate the possible existence of a putative p53-dependent pathway underlying the ASA-induced apoptosis in OC2 cells, a human oral cancer cell line. MATERIALS AND METHODS The methyl tetrazolium (MTT) assay was employed to quantify differences in cell viability. DNA ladder formation on agarose electrophoresis was used as apoptosis assay. The expression levels of several master regulatory molecules controlling various signal pathways were monitored using the immunoblotting techniques. Flow cytometry was used to confirm the effect of ASA on cell cycle. Patterns of changes in expression were scanned and analyzed using the NIH image 1.56 software (NIH, Bethesda, MD, USA). All the data were analyzed by ANOVA. RESULTS Acetylsalicylic acid reduced cell viability and presence of internucleosomal DNA fragmentation. In the meanwhile, phosphorylation of p53 at serine 15, accumulation of p53 and increased the expression of its downstream target genes, p21 and Bax induced by ASA. The expression of cyclooxygenase-2 was suppressed. Disruption of p53-murine double minute-2 (MDM2) complex formation resulted in increasing the expression of MDM2 60-kDa cleavage fragment. Inhibited the activation of p42/p44 mitogen-activated protein kinase (MAPK) by PD98059, a specific inhibitor of extracellular regulatory kinase (ERK), significantly decreased cell viability and enhanced the expression of p53 induced by ASA. The result of the cell-cycle analysis showed that ASA and PD98059 induced the cell cycle arrested at the G0/G1 phase and resulted in apoptosis. CONCLUSION Nonsteroidal anti-inflammatory drug-inhibited cyclooxygenase is not the only or even the most important mechanism of inhibition. Our study presents evidences that activation of p53 signalling involved in apoptosis induced by ASA. Furthermore, the apoptotic effect was enhanced by blocking the activation of p42/p44 MAPK in response to treatment with ASA, thus indicating a negative role for p42/p44 MAPK.
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Affiliation(s)
- C-C Ho
- Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan
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Hong H, Wei CM, Chou MY, Wu Z, Basile L, Chen H, Holt M, Chiang TC. Alternating layer and island growth of Pb on Si by spontaneous quantum phase separation. Phys Rev Lett 2003; 90:076104. [PMID: 12633252 DOI: 10.1103/physrevlett.90.076104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2002] [Indexed: 05/24/2023]
Abstract
Real-time in situ x-ray studies of continuous Pb deposition on Si(111)-(7x7) at 180 K reveal an unusual growth behavior. A wetting layer forms first to cover the entire surface. Then islands of a fairly uniform height of about five monolayers form on top of the wetting layer and grow to fill the surface. The growth then switches to a layer-by-layer mode upon further deposition. This behavior of alternating layer and island growth can be attributed to spontaneous quantum phase separation based on a first-principles calculation of the system energy.
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Affiliation(s)
- Hawoong Hong
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 S. Goodwin Avenue, Urbana, Illinois 61801-2902, USA
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Abstract
AIM The purpose of this study was to investigate the expression of cyclooxygenase-2 (COX-2) in radicular cysts. METHODOLOGY Thirty biopsy specimens of radicular cysts were examined using immunohistochemistry. A peroxidase-labelled streptavidin-biotin technique was used for identification of the COX-2. Fisher's exact test (two-tail) was used for statistical analysis of the results. RESULTS The result demonstrated that COX-2 expression was significantly higher in radicular cysts with higher levels of inflammatory infiltrates. COX-2 stain was detected in the lining epithelium, subepithelial fibroblasts, macrophages and endothelial cells in all specimens. CONCLUSIONS COX-2 expression is significantly higher in radicular cysts. COX-2 may play an important role in the pathogenesis of radicular cysts.
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Affiliation(s)
- C-H Tsai
- Department of Oral Pathology, Chung Shan Medical University Hospital, Taichung, Taiwan
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39
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Kidd TE, Miller T, Chou MY, Chiang TC. Electron-hole coupling and the charge density wave transition in TiSe2. Phys Rev Lett 2002; 88:226402. [PMID: 12059437 DOI: 10.1103/physrevlett.88.226402] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2001] [Indexed: 05/23/2023]
Abstract
Angle-resolved photoemission is employed to measure the band structure of TiSe2 in order to clarify the nature of the ( 2 x 2 x 2) charge density wave transition. The results show a very small indirect gap in the normal phase transforming into a larger indirect gap at a different location in the Brillouin zone. Fermi surface topology is irrelevant in this case. Instead, electron-hole coupling together with a novel indirect Jahn-Teller effect drives the transition.
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Affiliation(s)
- T E Kidd
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
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40
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Chou MY, Yang CH, Lu FI, Lin HC, Hwang PP. Modulation of calcium balance in tilapia larvae (Oreochromis mossambicus) acclimated to low-calcium environments. J Comp Physiol B 2002; 172:109-14. [PMID: 11916107 DOI: 10.1007/s00360-001-0231-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study examined how developing fish larvae regulate their Ca2+ balance for acclimation to low ambient Ca2+. Calcium balance in newly hatched larvae was examined individually. Developing larvae not only increased Ca2+ influx but also decreased Ca2+ efflux when they were acclimated to low-Ca2+ environments. After acclimation for 8 days, the influx and efflux of the low-Ca2+ (0.02 mM) group were about 106% and 43%, respectively, compared to those of the high-Ca2+ (1.0 mM) group. Sensitivity and response to low-Ca2+ environments are age-dependent. Upon acute exposure to low Ca2+. newly hatched (H0) larvae increased both Ca2+ influx (from 24% to 67% of high-Ca2+) and net uptake (from 5% to 69%) within 64 h, while 3-day-posthatching (H3) larvae managed to reach the levels of the control within 38 h. Declining Ca2+ efflux in H3 larvae occurred 14 h after exposure, much faster than those in H0 larvae (38 h). It is suggested that modulation of Ca2+-balance mechanisms in developing larvae is dependent upon the levels of Ca2+ in the larval body.
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Affiliation(s)
- M Y Chou
- Department of Biology, Tunghai University, Taichung, Taiwan, ROC
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41
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Huang FM, Tai KW, Chou MY, Chang YC. Cytotoxicity of resin-, zinc oxide-eugenol-, and calcium hydroxide-based root canal sealers on human periodontal ligament cells and permanent V79 cells. Int Endod J 2002; 35:153-8. [PMID: 11843970 DOI: 10.1046/j.1365-2591.2002.00459.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM The purpose of this study was to determine the cytotoxicity of three different types of root canal sealer on human periodontal ligament (PDL) cells and a permanent hamster cell line (V79 cells). METHODOLOGY Set specimens from two resin based sealers (AH26 and AHPlus), three zinc oxide-eugenol-based sealers (Canals, Endomethasone and N2) and one calcium hydroxide-based sealer (Sealapex) were eluted with culture medium for 1, 2, 3 and 7 days. Cytotoxicity was judged using tetrazolium bromide reduction assay on human primary PDL cells and V79 cells derived from a Chinese hamster. RESULTS The results showed that elutes from resin-based, zinc oxide-eugenol-based, and calcium hydroxide-based sealers were cytotoxic to primary human PDL cultures and V79 cells. Calcium hydroxide-based sealer was the least toxic sealer amongst the chemicals tested in both cultures. The cytotoxic response decreased in an order of N2 > Endomethasone > AH26 > AHplus > Canals > Sealapex. CONCLUSIONS The sensitivity of toxicity depended on the materials tested and the cell culture system used. Thus, the use of both permanent and primary cells is recommended for screening of the cytotoxic effects of root canal sealers. In addition, the results confirmed that root canal sealers constantly dissolve when exposed to an aqueous environment for extended periods, possibly causing moderate or severe cytotoxic reactions. Use of calcium hydroxide-based material as a root canal sealer initially may result in a more favourable response to periradicular tissues.
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Affiliation(s)
- F-M Huang
- Department of Dentistry, Chung Shan Medical and Dental College Hospital, Chung Shan Medical and Dental College, 23 Section 1 Taichung-Kang Road, Taichung, Taiwan
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42
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Abstract
The antibacterial effects of various types of widely used endodontic sealers have not been compared systematically on facultative or obligate anaerobic endodontic pathogens. The aim of this study was to evaluate the antimicrobial properties of four commonly used endodontic sealers: two epoxy-resin-based sealers (AH26, AH plus), one zinc-oxide eugenol-based sealer (N2), and one calcium hydroxide-based sealer (Sealapex). The testing microbes were four facultative anaerobic species (Streptococcus mutans, Streptococcus sanguis, Escherichia coli, and Staphylococcus aureus) and four obligate anaerobic species (Porphyromonas gingivalis, Porphyromonas endodontalis, Fusobacterium nucleatum, and Prevotella intermedia). The freshly mixed sealers were placed into the prepared wells of agar plates inoculated with the test microorganisms. After varying periods of incubation (2 days for facultative anaerobic species and 7 days for obligate anaerobic species), the zones of growth inhibition were observed and measured. All the sealers were distinctly different from each other in their antimicrobial activity. The sealers showed different inhibitory effects depending on the types and bacterial strains. N2 containing formaldehyde and eugenol proved to be the most effective against the microorganisms. The extreme antimicrobial potency of this root canal sealer must be weighted against its pronounced tissue toxic effect.
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Affiliation(s)
- C C Lai
- Institute of Stomatology, Chung Shan Medical and Dental College Taichung, Taiwan
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Abstract
The purpose of the study was to evaluate the presence of alteration of the tumor suppressor gene p16 and to correlate these changes with the clinical status of the patients in oral squamous cell carcinoma. Forty-eight oral squamous cell carcinomas were included in the analyses. Deletion analysis was performed by the polymerase chain reaction (PCR). Mutation analysis was restricted to exon 1 and exon 2 of the p16 gene, previously shown to have a high incidence of mutations. The sequences containing exon 1 and exon 2 were amplified by PCR and screened with a single-strand conformation polymorphism (SSCP) technique. Samples showing band shifts in SSCP were sequenced by PCR direct sequencing. Western blots were used to detect the protein expression of the p16 gene, and the results were evaluated with regard to their biological relevance in correlation with clinicopathological factors. Seven (14.6%) deletions were found; 5 (10.4%) mutations were discovered and located in different codons; 26 (54%) specimens had no p16 protein expression; in 11 specimens with p16 deletion or mutation, p16 protein could not be detected. One mutation was non-sense. The p16 gene alterations showed no relationship with location and clinical stage of cancer; however, a close relationship between p16 alterations and cancer metastasis to neck lymph node was found. The alteration rate gradually elevated from well to poorly differentiated grades. We perceive two results. First, the alterations of the p16 gene are common in oral squamous cell carcinoma. Second, the alterations of the p16 gene may attribute to the metastatic behavior or histological grade of cancer cells.
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Affiliation(s)
- C H Tsai
- Pathology Department, Chung Shan Medical and Dental College Hospital, 110, Sec. 1 Chien Kuo N. Road, Taichung 402, Taiwan, ROC
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Chang YC, Huang FM, Tai KW, Chou MY. The effect of sodium hypochlorite and chlorhexidine on cultured human periodontal ligament cells. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001; 92:446-50. [PMID: 11598582 DOI: 10.1067/moe.2001.116812] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The objective of this study was to examine the effects of sodium hypochlorite (NaOCl) and chlorhexidine (CHx) on cultured human periodontal ligament (PDL) cells in vitro. STUDY DESIGN The effects of irrigation solutions on human PDL cells were evaluated by propidium iodide fluorescence cytotoxicity assay, protein synthesis assay, and mitochondrial activity. RESULTS Both NaOCl and CHx were cytotoxic to human PDL cells in a concentration- and contact time-dependent manner. In addition, CHx inhibited protein synthesis in human PDL cells. Although NaOCl displayed cellular cytotoxicity, it showed no protein inhibition in the PDL cells. Furthermore, both NaOCl and CHx exhibited an inhibitory effect on mitochondrial activity on human PDL cells. CONCLUSIONS This study suggests that these irrigation fluids may cause detrimental effects on vital tissues. Its clinical significance, however, needs to be evaluated further because concentration used, exposure time to the agent, and exposure surface area are important factors affecting the resulting effect.
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Affiliation(s)
- Y C Chang
- School of Dentistry, Chung Shan Medical and Dental College, Taichung, Taiwan
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45
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Abstract
Areca quid chewing has been linked to oral submucous fibrosis and oral cancer. Arecoline, a major areca nut alkaloid, is considered to be the most important etiologic factor in the areca nut. In order to elucidate the pathobiological effects of arecoline, cytotoxicity assays, cellular glutathione S-transferase (GST) activity and lipid peroxidation assay were employed to investigate cultured human buccal mucosal fibroblasts. To date, there is a large proportion of areca quid chewers who are also smokers. Furthermore, nicotine, the major product of cigarette smoking, was added to test how it modulated the cytotoxicity of arecoline. At a concentration higher than 50 microg/ml, arecoline was shown to be cytotoxic to human buccal fibroblasts in a dose-dependent manner by the alamar blue dye colorimetric assay (P<0.05). In addition, arecoline significantly decreased GST activity in a dose-dependent manner (P<0.05). At concentrations of 100 microg/ml and 400 microg/ml, arecoline reduced GST activity about 21% and 46%, respectively, during a 24 h incubation period. However, arecoline at any test dose did not increase lipid peroxidation in the present human buccal fibroblast test system. The addition of extracellular nicotine acted synergistically on the arecoline-induced cytotoxicity. Arecoline at a concentration of 50 microg/ml caused about 30% of cell death over the 24 h incubation period. However, 2.5 mM nicotine enhanced the cytotoxic response and caused about 50% of cell death on 50 microg/ml arecoline-induced cytotoxicity. Taken together, arecoline may render human buccal mucosal fibroblasts more vulnerable to other reactive agents in cigarettes via GST reduction. The compounds of tobacco products may act synergistically in the pathogenesis of oral mucosal lesions in areca quid chewers. The data presented here may partly explain why patients who combined the habits of areca quid chewing and cigarette smoking are at greater risk of contracting oral cancer.
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Affiliation(s)
- Y C Chang
- Department of Dentistry, Chung Shan Medical and Dental College Hospital, Taichung, Taiwan
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Liao PH, Lee TL, Yang LC, Yang SH, Chen SL, Chou MY. Adenomatous polyposis coli gene mutation and decreased wild-type p53 protein expression in oral submucous fibrosis: a preliminary investigation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001; 92:202-7. [PMID: 11505268 DOI: 10.1067/moe.2001.116816] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The purpose of this study was to identify the adenomatous polyposis coli (APC) tumor suppressor gene mutation and level of wild-type p53 protein expression in patients with oral submucous fibrosis (OSF). STUDY DESIGN Cells from OSF and control subjects were cultured in Dulbecco modified Eagle medium with 10% fetal bovine serum at 37 degrees C. Genomic DNA was extracted from cultured cells and used as a template for polymerase chain reaction amplification of the APC tumor suppressor gene. The presence of wild-type p53 protein in cell lysates of cultured cells was analyzed by Western blot. Data were analyzed by the sign test for nonparametric samples and by analysis of variance. RESULTS The results showed that the APC gene of explant cultured cells from OSF patients (8/8) had a CGA-to-GGA transition mutation at codon 498 that resulted in an Arg-to-Gly missense mutation (P <.01). All (8/8) normal HGF cultures revealed expression of the wild-type APC protein. Cells cultured from 7 of 8 OSF patients were also found to have a single nucleotide deletion at nucleotide 1494 that resulted in creating a stop codon (TGA) at codon 504 (P <.01). This created a premature signal for the endpoint of translation and thus resulted in the generation of a truncated protein product that encodes a polypeptide of 503 amino acid residue. It was found that wild- type p53 protein in human gingival fibroblast cell cultures was significantly higher than in OSF cells (P <.01). CONCLUSION Alterations of the APC and wild-type p53 tumor suppressor genes in OSF may imply a risk for progression to oral cancer.
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Affiliation(s)
- P H Liao
- Departmnent of Dentistry, Chung Shan Medical and Dental College, Taichung, Taiwan, ROC
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Abstract
We have studied the structural stability of thin silver films with thicknesses of N = 1 to 15 monolayers, deposited on an Fe(100) substrate. Photoemission spectroscopy results show that films of N = 1, 2, and 5 monolayer thicknesses are structurally stable for temperatures above 800 kelvin, whereas films of other thicknesses are unstable and bifurcate into a film with N +/- 1 monolayer thicknesses at temperatures around 400 kelvin. The results are in agreement with theoretical predictions that consider the electronic energy of the quantum well associated with a particular film thickness as a significant contribution to the film stability.
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Affiliation(s)
- D A Luh
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080, USA
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48
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Abstract
The charge-density-wave transition in TiSe (2), which results in a commensurate (2x2x2) superlattice at temperatures below approximately 200 K, presumably involves softening of a zone-boundary phonon mode. For the first time, this phonon-softening behavior has been examined over a wide temperature range by synchrotron x-ray thermal diffuse scattering.
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Affiliation(s)
- M Holt
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
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Abstract
Betel nut chewing, like cigarette smoking, is a popular oral habit which impinges on the daily lives of a population of approximately 200 million. People who chew betel nuts have a higher prevalence of periodontal diseases than those who do not. Many of the undesirable effects of betel nuts have been attributed to arecoline, a major component of the particular alkaloid in betel nuts. In this in vitro study, we have focused on the effects of arecoline and the role it could play in periodontal breakdown via its direct effects on human gingival fibroblasts. Human gingival fibroblasts were derived from three healthy individuals undergoing crown-lengthening procedures. We found that arecoline is cytotoxic to human gingival fibroblasts at a concentration higher than 50 micrograms/ml by depleting intracellular thiols and inhibiting mitochondrial activity (P < 0.05). In addition, the cells displayed a marked arrest at G2/M phase in a dose-dependent manner. Repeated and long-term exposure to arecoline could impair the gingival fibroblast functions. As they are cytotoxic, the use of betel nut products in conjunction with periodontal therapy may interfere with optimal healing and/or lead to further periodontal breakdown.
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Affiliation(s)
- Y C Chang
- Institute of Stomatology, Chung Shan Medical and Dental College, 23 Section 1, Taichung-Kang Rd, Taichung, Taiwan
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50
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Abstract
BACKGROUND, AIMS The habit of betel nut chewing impinges on the daily lives of approximately 200 million people. Betel quid chewers have a higher prevalence of periodontal diseases than non-chewers. This study examined the pathobiological effects of arecoline, a major component of the betel nut alkaloids, on human periodontal ligament fibroblasts (PDLF) in vitro. METHOD Cell viability, proliferation, protein synthesis, and cellular thiol levels were used to investigate the effects of human PDLF exposed to arecoline levels of 0 to 200 microg/ml. In addition, nicotine was added to test how it modulated the effects of arecoline. RESULTS Arecoline significantly inhibited cell proliferation in a dose-dependent manner. At concentrations of 10 and 30 microg/ml, arecoline suppressed the growth of PDLF by 20% and 50% (p < 0.05), respectively. Arecoline also decreased protein synthesis in a dose-dependent manner during a 24-h culture period. A 100 microg/ ml concentration level of arecoline significantly inhibited protein synthesis to only 50% of that in the untreated control (p < 0.05). Moreover, arecoline significantly depleted intracellular thiols in a dose-dependent manner. At concentrations of 25 microg/ml and 100 microg/ml, arecoline depleted about 18% and 56% of thiols (p < 0.05), respectively. This suggests that arecoline itself might augment the destruction of periodontium associated with betel nut use. Furthermore, the addition of nicotine acted with a synergistic effect on the arecoline-induced cytotoxicity. At a concentration of 60 microg/ml, arecoline suppressed the growth of PDLF by about 33% and 5 mM nicotine enhanced the arecoline-induced cytotoxic response to cause about 66% cell death. CONCLUSION During thiol depletion, arecoline may render human PDLF more vulnerable to reactive agents within cigarettes. Taken together, people who combine habits of betel nut chewing with cigarette smoking could be more susceptible to periodontium damage than betel nut chewing alone.
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Affiliation(s)
- Y C Chang
- Department of Periodontics, Chung Shan Medical and Dental College Hospital, Taichung, Taiwan, ROC.
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