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Singh DK, Lee YS. Nonconventional spin glass transition in a chemically ordered pyrochlore. PHYSICAL REVIEW LETTERS 2012; 109:247201. [PMID: 23368369 DOI: 10.1103/physrevlett.109.247201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Indexed: 06/01/2023]
Abstract
We report on the study of unusual spin glass properties in the geometrically frustrated pyrochlore Tb(2)Mo(2)O(7), T(g) ~/= 24 K. The analysis of the nonlinear part of dc and complex susceptibilities, near the glass transition regime, suggests the existence of a statistical distribution of relaxation times in short-range ordered ferromagnetic clusters. In addition, the magnetic spins are not sufficiently frozen below the glass transition temperature, which is apparently responsible for the nonequilibrium scaling behavior of the static critical exponents of nonlinear susceptibilities. Our report is expected to shed new light in understanding the freezing properties of frustrated pyrochlores with short-range ferromagnetic interactions.
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102
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Hsu CC, Chang HY, Huang MC, Hwang SJ, Yang YC, Lee YS, Shin SJ, Tai TY. HbA1c variability is associated with microalbuminuria development in type 2 diabetes: a 7-year prospective cohort study. Diabetologia 2012; 55:3163-72. [PMID: 22923064 DOI: 10.1007/s00125-012-2700-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/25/2012] [Indexed: 12/16/2022]
Abstract
AIMS/HYPOTHESIS HbA(1c) variability has been shown to be an independent risk factor for nephropathy in patients with type 1 diabetes. In this study, we aimed to explore the association between HbA(1c) variability and microalbuminuria development in patients with type 2 diabetes. We also intended to test the applicability of serially measured HbA(1c) over 2 years for this risk assessment. METHODS Between 2003 and 2005, we recruited 821 middle-aged normoalbuminuric individuals with type 2 diabetes and followed them through to the end of 2010. The average follow-up time was 6.2 years. We defined microalbuminuria as a urine albumin to creatinine ratio of 30 mg/g (3.4 mg/mmol) or higher. HbA(1c) variability was calculated by the SD of serially measured HbA(1c). The Cox proportional hazards model was used to evaluate the association between HbA(1c) SD quartile and development of microalbuminuria. RESULTS The incidence of microalbuminuria for the overall population was 58.4, 58.6, 60.8 and 91.9 per 1,000 person-years for Q1- to Q4-adjusted HbA(1c) SD, respectively (p for trend = 0.042). Compared with patients in Q1, those in Q4 were about 37% more likely to develop microalbuminuria. The HR derived from a series of 2 year HbA(1c) measurements was similar to that from data collection for longer than 4 years. CONCLUSIONS/INTERPRETATION In addition to mean HbA(1c) values, HbA(1c) variability, even measured as early as 2 years, is independently associated with the development of microalbuminuria in patients with type 2 diabetes.
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Wang YH, Hsieh D, Sie EJ, Steinberg H, Gardner DR, Lee YS, Jarillo-Herrero P, Gedik N. Measurement of intrinsic dirac fermion cooling on the surface of the topological insulator Bi2Se3 using time-resolved and angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2012; 109:127401. [PMID: 23005985 DOI: 10.1103/physrevlett.109.127401] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Indexed: 06/01/2023]
Abstract
We perform time- and angle-resolved photoemission spectroscopy of a prototypical topological insulator (TI) Bi(2)Se(3) to study the ultrafast dynamics of surface and bulk electrons after photoexcitation. By analyzing the evolution of surface states and bulk band spectra, we obtain their electronic temperature and chemical potential relaxation dynamics separately. These dynamics reveal strong phonon-assisted surface-bulk coupling at high lattice temperature and total suppression of inelastic scattering between the surface and the bulk at low lattice temperature. In this low temperature regime, the unique cooling of Dirac fermions in TI by acoustic phonons is manifested through a power law dependence of the surface temperature decay rate on carrier density.
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Oh YC, Kang OH, Kim SB, Mun SH, Park CB, Kim YG, Kim YI, Lee YS, Han SH, Keum JH, Shin DW, Ma JY, Kwon DY. Anti-inflammatory effect of sinomenine by inhibition of pro-inflammatory mediators in PMA plus A23187-stimulated HMC-1 Cells. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2012; 16:1184-1191. [PMID: 23047501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND OBJECTIVES Sinomenine is an alkaloid compound and a prominent anti-inflammatory agent found in the root of the climbing plant Sinomenium acutum. However, its effects on the mechanism of human mast cell line (HMC)-1-mediated inflammation remained unknown. MATERIALS AND METHODS To provide insight into the biological effects of sinomenine, we examined its influence on the pro-inflammatory cytokine production in HMC-1 cells stimulated by phorbol 12-myristate-13-acetate (PMA) plus A23187 by evaluating the stimulated cells in the presence or absence of sinomenine. In the present study, the pro-inflammatory cytokine production was measured using ELISA, Reverse Transcription-polymerase chain reaction (RT-PCR) and nuclear factor (NF)-kappaB, mitogen-activated protein kinases (MAPKs) pathway activation, as determined by Western blot analysis. Also, cyclooxygenase (COX)-2 expression was measured through Western blot and RT-PCR analysis. RESULTS Sinomenine inhibited the pro-inflammatory cytokine production induced by PMA plus A23187 in a dose-dependent manner. Furthermore, sinomenine inhibited the phosphorylations of extracellular signal-regulated kinase (ERK) and p38 MAPKs as well as the translocation of NF-kappaB p65 through reduced IkappaBalpha degradation. In addition, sinomenine suppressed COX-2 protein and mRNA expression dose-dependently. CONCLUSIONS Taken together, the results of this study indicate that the anti-inflammatory effects of sinomenine may occur via the inhibition of pro-inflammatory cytokine and COX-2 production through the inhibition of MAPKs and NF-kappaB pathway activation by PMA plus A23187 stimulation in HMC-1 cells.
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Lee YS, Choi I, Ning Y, Kim NY, Khatchadourian V, Yang D, Chung HK, Choi D, LaBonte MJ, Ladner RD, Nagulapalli Venkata KC, Rosenberg DO, Petasis NA, Lenz HJ, Hong YK. Interleukin-8 and its receptor CXCR2 in the tumour microenvironment promote colon cancer growth, progression and metastasis. Br J Cancer 2012; 106:1833-41. [PMID: 22617157 PMCID: PMC3364111 DOI: 10.1038/bjc.2012.177] [Citation(s) in RCA: 226] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is a leading cause of death in the United States. Increased level of interleukin-8 (IL-8) and CXCR2 on tumours and in the tumour microenvironment has been associated with CRC growth, progression and recurrence in patients. Here, we aimed to evaluate the effects of tissue microenvironment-encoded IL-8 and CXCR2 on colon cancer progression and metastasis. METHODS A novel immunodeficient, skin-specific IL-8-expressing transgenic model was generated to evaluate colon cancer growth and metastasis. Syngeneic mouse colon cancer cells were grafted in CXCR2 knockout (KO) mice to study the contribution of CXCR2 in the microenvironment to cancer growth. RESULTS Elevated levels of IL-8 in the serum and tumour microenvironment profoundly enhanced the growth of human and mouse colon cancer cells with increased peri-tumoural angiogenesis, and also promoted the extravasation of the cancer cells into the lung and liver. The tumour growth was inhibited in CXCR2 KO mice with significantly reduced tumour angiogenesis and increased tumour necrosis. CONCLUSION Increased expression of IL-8 in the tumour microenvironment enhanced colon cancer growth and metastasis. Moreover, the absence of its receptor CXCR2 in the tumour microenvironment prevented colon cancer cell growth. Together, our study demonstrates the critical roles of the tumour microenvironment-encoded IL-8/CXCR2 in colon cancer pathogenesis, validating the pathway as an important therapeutic target.
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Teo AE, Ng AC, Venkataraman K, Tai ES, Lee YS, Khoo EY, Khoo CM, Sadananthan SA, Velan SS, Zagorodnov V, Chong YS, Gluckman P, Leow MK. Ethnic differences in the association of fat and lean mass with bone mineral density in the Singapore population. BMC Proc 2012. [PMCID: PMC3426076 DOI: 10.1186/1753-6561-6-s4-p43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Choi JG, Lee MW, Choi SE, Kim MH, Kang OH, Lee YS, Chae HS, Obiang-Obounou B, Oh YC, Kim MR, Shin DW, Lee JH, Kwon DY. Antibacterial activity of bark of Alnus pendula against methicillin-resistant Staphylococcus aureus. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2012; 16:853-859. [PMID: 22953631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND OBJECTIVES Methicillin-resistant Staphylococcus aureus (MRSA) infections are a rapidly growing health problem around the globe. Recently, there has been considerable interest in the use of plant materials as an alternative method to control pathogenic microorganisms. In this study we evaluated the antibacterial activity of bark of Alnus pendula against MRSA. MATERIALS AND METHODS The MIC determination was done using the microdilution broth method and bacterial growth was determined by measuring optical density using spectrophotometer. RESULTS Alnus pendula bark EtOH extract and fractions (F-1, -2, -3 and -4) were investigated against MRSA. The most active fractions (F-3 and F-4) led to the isolation of oregonin (ORE) and hirsutanone (HIR). These compounds were active against MRSA strains with minimum inhibitory concentrations (MICs) ranging from 31.25 to 250 microg/ml MIC and 2 MIC of HIR completely inhibited the growth of MRSA. CONCLUSIONS The bark EtOH extract of Alnus Pendula has potent antibacterial activity against MRSA.
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Choi SW, Han JM, Bae YJ, Lee YS, Cho YS, Moon HB, Kim TB. Lessons from two cases of anaphylaxis to proton pump inhibitors. J Clin Pharm Ther 2012; 37:614-6. [PMID: 22642701 DOI: 10.1111/j.1365-2710.2012.01348.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Proton pump inhibitors (PPIs), which are widely used for the treatment of peptic ulcers and gastroesophageal diseases, reduce both basal and stimulated gastric acid secretion by inhibiting the parietal cell enzyme H(+)-K(+)-adenosine triphosphatase. There have been several reports of hypersensitivity reactions to PPIs but anaphylaxis is very rare. We report on two cases of anaphylaxis to PPIs. CASE SUMMARY Our two interesting and instructive cases of anaphylaxis to PPIs relate to the orally disintegrating form of lansoprazole and omeprazole. The first patient had taken esomeprazole 20 mg/day for 1 month without any side effects before experiencing anaphylaxis to lansoprazole. To our knowledge, this is the first report of anaphylaxis to the orally disintegrating form of lansoprazole. In the second case, the patient was misdiagnosed with penicillin allergy which she suffered from earlier. WHAT IS NEW AND CONCLUSION Physicians need to be more aware of the possibility of hypersensitivity to PPIs.
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Pan ZH, Fedorov AV, Gardner D, Lee YS, Chu S, Valla T. Measurement of an exceptionally weak electron-phonon coupling on the surface of the topological insulator Bi2Se3 using angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2012; 108:187001. [PMID: 22681106 DOI: 10.1103/physrevlett.108.187001] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Indexed: 06/01/2023]
Abstract
Gapless surface states on topological insulators are protected from elastic scattering on nonmagnetic impurities which makes them promising candidates for low-power electronic applications. However, for widespread applications, these states should have to remain coherent at ambient temperatures. Here, we studied temperature dependence of the electronic structure and the scattering rates on the surface of a model topological insulator, Bi2Se3, by high-resolution angle-resolved photoemission spectroscopy. We found an extremely weak broadening of the topological surface state with temperature and no anomalies in the state's dispersion, indicating exceptionally weak electron-phonon coupling. Our results demonstrate that the topological surface state is protected not only from elastic scattering on impurities, but also from scattering on low-energy phonons, suggesting that topological insulators could serve as a basis for room-temperature electronic devices.
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Han KJ, Kim JY, Chung NS, Lee HR, Lee YS. Trabecular microstructure of the human lunate in Kienbock's disease. J Hand Surg Eur Vol 2012; 37:336-41. [PMID: 21965181 DOI: 10.1177/1753193411422337] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The trabecular microstructure of normal lunates and lunates with Kienböck's disease was investigated using micro-computed tomography (micro-CT). Five lunates with advanced Kienböck's disease were obtained during lunate excision and scaphocapitate fusion, and five control lunates were from embalmed cadavers. Microstructural morphometric parameters were measured using micro-CT images. Trabeculations of lunates with Kienböck's disease were 2.67 times denser and 1.84 times thicker than those of normal lunates. Furthermore, bone surface areas were 1.43 times greater and bone volume 2.67 times greater, and structural model indices were significantly lower in lunates with Kienböck's disease. The study estimated that high mechanical stress would be applied to lunates with Kienböck's disease, and suggests that new bone formation and collapse may play important roles in the microstructural changes in the lunate with advanced Kienböck's disease.
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Ji JH, Shafi M, Lee YS, Kim DJ. Inferior paralabral ganglion cyst of the shoulder with labral tear -- a rare cause of shoulder pain. Orthop Traumatol Surg Res 2012; 98:193-8. [PMID: 22386705 DOI: 10.1016/j.otsr.2011.09.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 09/18/2011] [Accepted: 09/26/2011] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Paralabral ganglion cysts of the shoulder are rare, and their pathogenesis is similar to that of meniscal cysts. The paralabral cysts are most frequently reported along the posterior, superior, and anterior aspects of the glenohumeral joint and are uncommon inferiorly to the joint. These cysts rarely become evident clinically, unless they cause compression of surrounding structures, i.e. nerve. PATIENTS AND METHODS We report a retrospective series of five patients with inferior paralabral ganglion cysts of the shoulder without compression of the surrounding nerve which were treated during the period from March 2007 to December 2009. All these patients presented with only chronic shoulder pain as their chief complaint, and preoperative MRI showed the cyst over the inferior aspect of a torn glenoid labrum. All patients were treated by arthroscopic cystic decompression with labrum repair. All patients were re-evaluated with MRI performed at an average of 15 months postoperatively. The clinical outcome, including the Constant score, was assessed for all patients at a median of 16 months postoperatively. RESULTS All the five patients had remission of pain and were satisfied with the shoulder function. The postoperative MRI in all patients showed no labral cyst recurrence. The median Constant score improved from a preoperative level of 81.5 points to 98.0 points at last follow-up. CONCLUSION This study demonstrates that, in the absence of any nerve compression symptoms around the shoulder joint, inferior paralabral cysts with labral tear also be considered in the differential diagnosis of chronic shoulder pain. Arthroscopic repair of the cyst with repair of the labrum can lead to the disappearance of symptoms. Knowledge of this clinical condition and its imaging features is critical for a correct diagnosis of this uncommon cause of chronic shoulder pain. LEVEL OF EVIDENCE Level IV. Retrospective therapeutic study.
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Valla T, Pan ZH, Gardner D, Lee YS, Chu S. Photoemission spectroscopy of magnetic and nonmagnetic impurities on the surface of the Bi2Se3 topological insulator. PHYSICAL REVIEW LETTERS 2012; 108:117601. [PMID: 22540510 DOI: 10.1103/physrevlett.108.117601] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Indexed: 05/31/2023]
Abstract
Dirac-like surface states on surfaces of topological insulators have a chiral spin structure that suppresses backscattering and protects the coherence of these states in the presence of nonmagnetic scatterers. In contrast, magnetic scatterers should open the backscattering channel via the spin-flip processes and degrade the state's coherence. We present angle-resolved photoemission spectroscopy studies of the electronic structure and the scattering rates upon the adsorption of various magnetic and nonmagnetic impurities on the surface of Bi2Se3, a model topological insulator. We reveal a remarkable insensitivity of the topological surface state to both nonmagnetic and magnetic impurities in the low impurity concentration regime. Scattering channels open up with the emergence of hexagonal warping in the high-doping regime, irrespective of the impurity's magnetic moment.
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Lee YS, Tae K, Lee SH, Cho SH, Jeong JH, Min HJ, Ji YB. Change of telomerase activity in peripheral whole blood of head and neck squamous cell carcinoma patients before and after surgery: a pilot study. Clin Transl Oncol 2012; 13:747-53. [PMID: 21975338 DOI: 10.1007/s12094-011-0727-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The purpose of this study was to evaluate telomerase activity in peripheral whole blood from head and neck squamous cell carcinoma (HNSCC) patients as a biomarker for diagnosis of HNSCC or detection of recurrence during follow-up. MATERIALS AND METHODS Telomerase activity was measured from peripheral whole blood extracts by telomerase repeat amplification protocol (TRAP) in HNSCC patients before and after surgery and in a control group. Sixty-two HNSCC patients and 42 control subjects were included. RESULTS Telomerase activity was found in 41 out of 62 (66.1%) HNSCC patients before surgery and in 8 out of 42 (19.0%) controls (p<0.001). Among 41 HNSCC patients who showed positive telomerase activity before surgery, 32 (78.1%) showed a conversion of telomerase activity to negative after surgery. In follow-up, 6 out of 8 (75%) showed conversion of telomerase activity from negative to positive after recurrence. Telomerase activity was changed to negative in 4 out of 6 (66%) recurred patients with positive telomerase activity after second surgery. CONCLUSION The telomerase activity in peripheral whole blood extracts of HNSCC patients might be a useful biomarker for detecting recurrence after treatment. Further study with larger sample size using a more sensitive detection method of telomerase activity is necessary to verify these results.
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Kwon JH, Jang JW, Lee S, Lee J, Chung KW, Lee YS, Choi JY. Pretreatment HBeAg level and an early decrease in HBeAg level predict virologic response to entecavir treatment for HBeAg-positive chronic hepatitis B. J Viral Hepat 2012; 19:e41-7. [PMID: 22239525 DOI: 10.1111/j.1365-2893.2011.01509.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There are few reports on hepatitis B e antigen (HBeAg) titres during nucleos(t)ide analogues treatment. We investigated the changes in HBeAg levels in patients treated with entecavir and the usefulness of HBeAg quantification for predicting antiviral response. Ninety-five consecutive HBeAg-positive patients treated with entecavir for more than 48 weeks were enrolled. Serum levels of hepatitis B surface antigen (HBsAg), HBeAg and HBV DNA were assessed at 4-week intervals to week 24 and thereafter at 12-week intervals. Virologic response (Y1VR) was defined as an undetectable HBV DNA level at week 48 of therapy. During 48 weeks, HBeAg and HBV DNA level decreased significantly in a biphasic manner and HBsAg level tended to decease. Fifty-three patients (55.8%) attained Y1VR. Pretreatment HBeAg levels were significantly lower in the Y1VR group than in no Y1VR group. At week 4 and 12 of therapy, 25% and 41.4% of patients showed a decrease of HBeAg levels with >0.5 log(10) and >1.0 log(10) from baseline, respectively. These patients achieved more Y1VR than those with less decrease of HBeAg levels (97.7%vs 22.2% and 86.2%vs 29.3%, respectively). HBeAg level at week 12 had higher predictive values for Y1VR than HBV DNA level. Multivariate analysis revealed that a pretreatment HBeAg level of <360 PEIU/mL and the reduction in HBeAg level >1.0 log(10) at week 12 were associated with Y1VR. These results suggest that pretreatment HBeAg level and an early decrease in HBeAg level are useful measurements for predicting one-year virologic response during entecavir treatment.
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Wang YH, Hsieh D, Pilon D, Fu L, Gardner DR, Lee YS, Gedik N. Observation of a warped helical spin texture in Bi2Se3 from circular dichroism angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2011; 107:207602. [PMID: 22181776 DOI: 10.1103/physrevlett.107.207602] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Indexed: 05/31/2023]
Abstract
A differential coupling of topological surface states to left- versus right-circularly polarized light is the basis of many optospintronics applications of topological insulators. Here we report direct evidence of circular dichroism from the surface states of Bi(2)Se(3) using laser-based time-of-flight angle-resolved photoemission spectroscopy. By employing a novel sample rotational analysis, we resolve unusual modulations in the circular dichroism photoemission pattern as a function of both energy and momentum, which perfectly mimic the predicted but hitherto unobserved three-dimensional warped spin texture of the surface states. By developing a microscopic theory of photoemission from topological surface states, we show that this correlation is a natural consequence of spin-orbit coupling. These results suggest that our technique may be a powerful probe of the spin texture of spin-orbit coupled materials in general.
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Bae YJ, Kim YS, Park CS, Lee YS, Chang YS, Cho YS, Jang AS, Cho SH, Choi BW, Kim SG, Moon HB, Kim TB. Reliability and validity of the St George's Respiratory Questionnaire for asthma. Int J Tuberc Lung Dis 2011; 15:966-71. [PMID: 21682973 DOI: 10.5588/ijtld.10.0603] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The St George's Respiratory Questionnaire (SGRQ) is a self-administered questionnaire that has been used to evaluate the health-related quality of life of patients with chronic respiratory diseases. OBJECTIVE To assess the validity and reliability of the SGRQ for a large population with asthma. DESIGN We used the previously developed Korean version of the SGRQ (SGRQ-K) to assess 676 asthma patients enrolled from the Cohort for Reality and Evolution of Adult Asthma in Korea study. Cronbach's α was used to assess test reliability and Pearson's correlation coefficient was used to assess the correlation between SGRQ scores and various clinical factors. RESULTS The total SGRQ-K score had acceptable reliability (Cronbach's α = 0.92). The total SGRQ-K score was significantly correlated with symptom duration (r = 0.157, P < 0.001), pulmonary function (% FEV(1) of predicted r = -0.314, P < 0.001; % FVC of predicted r = -0.224, P < 0.001; FEV(1)/FVC r = -0.224, P < 0.001), asthma severity (r = 0.278, P < 0.001) and history of asthma exacerbation. CONCLUSION With the exception of the SGRQ-K symptoms, SGRQ-K is a reliable and valid test for evaluation of the quality of life of patients with asthma. Scores were well correlated with duration of symptoms, lung function and previous history of asthma exacerbation.
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Kim JM, Lee KT, Lim KS, Park EW, Lee YS, Hong KC. Effects of p.C430S polymorphism in the PPARGC1A gene on muscle fibre type composition and meat quality in Yorkshire pigs. Anim Genet 2011; 41:642-5. [PMID: 20412126 DOI: 10.1111/j.1365-2052.2010.02042.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The peroxisome proliferator-activated receptor-gamma coactivator-1A (encoded by PPARGC1A) is involved in the formation of type I fibres. Therefore, the PPARGC1A gene can be considered as a functional candidate gene for muscle fibre type composition and meat quality in pigs. The aim of this study was to investigate the associations of the p.C430S polymorphic site in exon 8 of the PPARGC1A gene with muscle fibre characteristics and meat quality traits. The polymorphism was genotyped by PCR-RFLP using AluI restriction enzyme on a total of 152 Yorkshire pigs. Statistical analyses revealed that the p.C430S genotypes significantly affected number (P < 0.05) and area (P < 0.01) of type I muscle fibre, and were significantly associated with muscle pH (P < 0.001) and lightness(P < 0.01). On the basis of these results, we suggest that the p.C430S polymorphism can induce variation of type I fibre formation in porcine longissimus dorsi muscle and that it can be used as a meaningful molecular marker for better meat quality.
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Hsieh D, Mahmood F, McIver JW, Gardner DR, Lee YS, Gedik N. Selective probing of photoinduced charge and spin dynamics in the bulk and surface of a topological insulator. PHYSICAL REVIEW LETTERS 2011; 107:077401. [PMID: 21902428 DOI: 10.1103/physrevlett.107.077401] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/01/2011] [Indexed: 05/27/2023]
Abstract
Topological insulators possess completely different spin-orbit coupled bulk and surface electronic spectra that are each predicted to exhibit exotic responses to light. Here we report time-resolved fundamental and second harmonic optical pump-probe measurements on the topological insulator Bi(2)Se(3) to independently measure its photoinduced charge and spin dynamics with bulk and surface selectivity. Our results show that a transient net spin density can be optically induced in both the bulk and surface, which may drive spin transport in topological insulators. By utilizing a novel rotational anisotropy analysis we are able to separately resolve the spin depolarization, intraband cooling, and interband recombination processes following photoexcitation, which reveal that spin and charge degrees of freedom relax on very different time scales owing to strong spin-orbit coupling.
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Pan ZH, Vescovo E, Fedorov AV, Gardner D, Lee YS, Chu S, Gu GD, Valla T. Electronic structure of the topological insulator Bi2Se3 using angle-resolved photoemission spectroscopy: evidence for a nearly full surface spin polarization. PHYSICAL REVIEW LETTERS 2011; 106:257004. [PMID: 21770666 DOI: 10.1103/physrevlett.106.257004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Indexed: 05/31/2023]
Abstract
We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi2Se3, a model TI. By tuning the photon energy, we found that the topological surface state is well separated from the bulk states in the vicinity of kz = Z plane of the bulk Brillouin zone. The spin-resolved measurements in that region indicate a very high degree of spin polarization of the surface state, ~0.75, much higher than previously reported. Our results demonstrate that the topological surface state on Bi2Se3 is highly spin polarized and that the dominant factors limiting the polarization are mainly extrinsic.
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Yang WM, Jung KJ, Lee MO, Lee YS, Lee YH, Nakagawa S, Niwa M, Cho SS, Kim DW. Transient expression of iron transport proteins in the capillary of the developing rat brain. Cell Mol Neurobiol 2011; 31:93-9. [PMID: 21061168 DOI: 10.1007/s10571-010-9558-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 08/11/2010] [Indexed: 11/28/2022]
Abstract
Iron is essential for normal brain function and its uptake in the developing rat brain peaks during the first two weeks after birth, prior to the formation of the blood–brain barrier (BBB). The first step of iron transport from the blood to the brain is transferrin receptor (TfR)-mediated endocytosis in the capillary endothelial cells. However, the subsequent step from the endothelium into interstitium has not been fully described. The goal of this study was to examine the expression of iron transport proteins by immunodetection and RT–PCR in the developing rat brain. Tf and TfR are transiently expressed in perivascular NG2+ cells of the capillary wall during the early postnatal weeks in the rat brain. However, MTP-1 and hephaestin were expressed in endothelial cells, but not in the NG2+ perivascular cells. Immunoblot analysis for these iron transfer proteins in the developing brain generally confirmed the immunochemical findings. Furthermore, the expression of Tf and TfR in the blood vessels precedes its expression in oligodendrocytes, the main iron-storing cells in the vertebrate brain. RT–PCR analysis for the primary culture of endothelial cells and pericytes revealed that Tf and TfR were highly expressed in the pericytes while MTP-1 and hephaestin were expressed in the endothelial cells. The specific expression of Tf and TfR in brain perivascular cells and MTP-1 and hephaestin in endothelial cells suggest the possibility that trafficking of elemental iron through perivascular cells may be instrumental in the distribution of iron in the developing central nervous system.
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Kam G, Lee YS, Tan TT, Chow P, Ng HJ. Surgery-associated acquired haemophilia and response to combined rituximab and cyclosporine treatment. Haemophilia 2011; 17:715-6. [PMID: 21362110 DOI: 10.1111/j.1365-2516.2010.02458.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Choi SU, Shin HW, Jung HI, Park JY, Yoon SZ, Lee YS, Kim WY, Chang SH. Control of the haemodynamic response to surgical stimuli in semi-closed circuit or closed circuit anaesthesia using a multifunctional anaesthesia system. J Int Med Res 2011; 38:1637-44. [PMID: 21309477 DOI: 10.1177/147323001003800508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This study compared the ability of the Zeus multifunctional anaesthesia system to control haemodynamic response to surgical stimulation in semi-closed (SCA) or closed circuit anaesthesia (CCA) modes. Fifty patients undergoing gynaecological surgery were randomly assigned to SCA or CCA. Anaesthesia was induced with 2 mg propofol and 0.9 mg/kg rocuronium, intravenously, and maintained using sevoflurane (minimum alveolar concentration [MAC], 1.0) using 2 l/min oxygen plus 2 l/min nitrous oxide (SCA 4 l/min group) or 50% oxygen plus 50% nitrous oxide (CCA group). An increase in mean arterial pressure (MAP) > 20% above baseline in response to surgical stimulation provoked a stepwise increase in sevoflurane (1.3 MAC and then 1.6 MAC), followed by fentanyl 1 pg/kg intravenously (rescue drug). The time required for MAP to return to within 10% of baseline was significantly shorter in the CCA group (6.4 +/- 3.6 min) compared with the SCA 4 l/min group (10.2 +/- 6.0 min). The percentage of patients requiring fentanyl was significantly greater in the SCA 4 l/min group than in the CCA group. In conclusion, CCA controlled acute haemodynamic responses to surgical stimuli more successfully and rapidly than SCA 4 l/min, using a multifunctional anaesthesia machine.
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Hsieh D, McIver JW, Torchinsky DH, Gardner DR, Lee YS, Gedik N. Nonlinear optical probe of tunable surface electrons on a topological insulator. PHYSICAL REVIEW LETTERS 2011; 106:057401. [PMID: 21405434 DOI: 10.1103/physrevlett.106.057401] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Indexed: 05/23/2023]
Abstract
We use ultrafast laser pulses to experimentally demonstrate that the second-order optical response of bulk single crystals of the topological insulator Bi(2)Se(3) is sensitive to its surface electrons. By performing surface doping dependence measurements as a function of photon polarization and sample orientation we show that second harmonic generation can simultaneously probe both the surface crystalline structure and the surface charge of Bi(2)Se(3). Furthermore, we find that second harmonic generation using circularly polarized photons reveals the time-reversal symmetry properties of the system and is surprisingly robust against surface charging, which makes it a promising tool for spectroscopic studies of topological surfaces and buried interfaces.
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Park KA, Cho WI, Song KJ, Lee YS, Sung IS, Choi-Kwon SM. Assessment of nurses' nutritional knowledge regarding therapeutic diet regimens. NURSE EDUCATION TODAY 2011; 31:192-197. [PMID: 20621397 DOI: 10.1016/j.nedt.2010.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 04/14/2010] [Accepted: 05/25/2010] [Indexed: 05/29/2023]
Abstract
Metabolic diseases and cardiovascular disease (CVD), the incidence of which is currently increasing in Korea, can be managed well with dietary education and modification. However, it has yet to be established whether nurses have sufficient knowledge to impart appropriate nutritional counseling to patients with these diseases. Our study involved 506 nurses working at Asan Medical Center, Samsung Medical Center, and Seoul National University Hospital between March and May, 2006. The questionnaire was comprised of 42 diet-related questions pertaining to diabetes, obesity, and CVD. Nurses' correct-response rate for overall nutritional knowledge was worse than reported in Western countries (58.4%), and particularly so with regard to obesity and CVD. Although many nurses were aware of the therapeutic aspects of nutrients in relation to CVD, most of them had limited knowledge about low-cholesterol diets and sources of water-soluble fiber, fatty acids and the specific food items that prevent CVD. Our results suggest that there is an urgent need to update the contents of nutrition education for nurses to reflect the current changes in the Korean diet and the increasing incidence of metabolic diseases and CVD.
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Shilyansky C, Lee YS, Silva AJ. Molecular and cellular mechanisms of learning disabilities: a focus on NF1. Annu Rev Neurosci 2011; 33:221-43. [PMID: 20345245 DOI: 10.1146/annurev-neuro-060909-153215] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurofibromatosis Type I (NF1) is a single-gene disorder characterized by a high incidence of complex cognitive symptoms, including learning disabilities, attention deficit disorder, executive function deficits, and motor coordination problems. Because the underlying genetic cause of this disorder is known, study of NF1 from a molecular, cellular, and systems perspective has provided mechanistic insights into the etiology of higher-order cognitive symptoms associated with the disease. In particular, studies of animal models of NF1 indicated that disruption of Ras regulation of inhibitory networks is critical to the etiology of cognitive deficits associated with NF1. Animal models of Nf1 identified mechanisms and pathways that are required for cognition, and represent an important complement to the complex neuropsychological literature on learning disabilities associated with this condition. Here, we review findings from NF1 animal models and human populations affected by NF1, highlighting areas of potential translation and discussing the implications and limitations of generalizing findings from this single-gene disease to idiopathic learning disabilities.
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