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Liu Y, Wang HH, Bian G, Zhang Z, Lee SS, Fenter PA, Tischler JZ, Hong H, Chiang TC. Interfacial bonding and structure of Bi2Te3 topological insulator films on Si(111) determined by surface x-ray scattering. PHYSICAL REVIEW LETTERS 2013; 110:226103. [PMID: 23767736 DOI: 10.1103/physrevlett.110.226103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/25/2013] [Indexed: 06/02/2023]
Abstract
Interfacial topological states are a key element of interest for topological insulator thin films, and their properties can depend sensitively on the atomic bonding configuration. We employ in situ nonresonant and resonant surface x-ray scattering to study the interfacial and internal structure of a prototypical topological film system: Bi2Te3 grown on Si(111). The results reveal a Te-dominated buffer layer, a large interfacial spacing, and a slightly relaxed and partially strained bottom quintuple layer of an otherwise properly stacked bulklike Bi2Te3 film. The presence of the buffer layer indicates a nontrivial process of interface formation and a mechanism for electronic decoupling between the topological film and the Si(111) substrate.
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Chen Y, Lee B, Yi HT, Lee SS, Payne MM, Pola S, Kuo CH, Loo YL, Anthony JE, Tao YT, Podzorov V. Dynamic character of charge transport parameters in disordered organic semiconductor field-effect transistors. Phys Chem Chem Phys 2013; 14:14142-51. [PMID: 22868385 DOI: 10.1039/c2cp41823a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this perspective article, we discuss the dynamic instability of charge carrier transport in a range of popular organic semiconductors. We observe that in many cases field-effect mobility, an important parameter used to characterize the performance of organic field-effect transistors (OFETs), strongly depends on the rate of the gate voltage sweep during the measurement. Some molecular systems are so dynamic that their nominal mobility can vary by more than one order of magnitude, depending on how fast the measurements are performed, making an assignment of a single mobility value to devices meaningless. It appears that dispersive transport in OFETs based on disordered semiconductors, those with a high density of localized trap states distributed over a wide energy range, is responsible for the gate voltage sweep rate dependence of nominal mobility. We compare such rate dependence in different materials and across different device architectures, including pristine and trap-dominated single-crystal OFETs, as well as solution-processed polycrystalline thin-film OFETs. The paramount significance given to a single mobility value in the organic electronics community and the practical importance of OFETs for applications thus suggest that such an issue, previously either overlooked or ignored, is in fact a very important point to consider when engaging in fundamental studies of charge carrier mobility in organic semiconductors or designing applied circuits with organic semiconductors.
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Kim JH, Kim SJ, Lee WY, Cheon YH, Lee SS, Ju A, K M, Kim DJ. The Effects of Alcohol Abstinence on BDNF, Ghrelin, and Leptin Secretions in Alcohol-Dependent Patients with Glucose Intolerance. Alcohol Clin Exp Res 2012; 37 Suppl 1:E52-8. [DOI: 10.1111/j.1530-0277.2012.01921.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 07/02/2012] [Indexed: 01/15/2023]
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Han SW, Sa KH, Kim SI, Lee SI, Park YW, Lee SS, Yoo WH, Soe JS, Nam EJ, Lee J, Park JY, Kang YM. CCR5 gene polymorphism is a genetic risk factor for radiographic severity of rheumatoid arthritis. ACTA ACUST UNITED AC 2012; 80:416-23. [PMID: 22924548 DOI: 10.1111/j.1399-0039.2012.01955.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 07/11/2012] [Accepted: 08/06/2012] [Indexed: 11/29/2022]
Abstract
The chemokine receptor [C-C chemokine receptor 5 (CCR5)] is expressed on diverse immune effecter cells and has been implicated in the pathogenesis of rheumatoid arthritis (RA). This study sought to determine whether single-nucleotide polymorphisms (SNPs) in the CCR5 gene and their haplotypes were associated with susceptibility to and severity of RA. Three hundred fifty-seven patients with RA and 383 healthy unrelated controls were recruited. Using a pyrosequencing assay, we examined four polymorphisms -1118 CTAT(ins) (/del) (rs10577983), 303 A>G (rs1799987), 927 C>T (rs1800024), and 4838 G>T (rs1800874) of the CCR5 gene, which were distributed over the promoter region as well as the 5' and 3' untranslated regions. No significant difference in the genotype, allele, and haplotype frequencies of the four selected SNPs was observed between RA patients and controls. CCR5 polymorphisms of -1118 CTAT(del) (P = 0.012; corrected P = 0.048) and 303 A>G (P = 0.012; corrected P = 0.048) showed a significant association with radiographic severity in a recessive model, and, as a result of multivariate logistic regression analysis, were found to be an independent predictor of radiographic severity. When we separated the erosion score from the total Sharp score, the statistical significance of CCR5 polymorphisms showed an increase; -1118 CTAT(ins) (/del) (P = 0.007; corrected P = 0.028) and 303 A>G (P = 0.007; corrected P = 0.028). Neither SNPs nor haplotypes of the CCR5 gene showed a significant association with joint space narrowing score. These results indicate that genetic polymorphisms of CCR5 are an independent risk factor for radiographic severity denoted by modified Sharp score, particularly joint erosion in RA.
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Lee SS, Wong NS. Relationship between population configuration and the spatial pattern of pandemic influenza A (H1N1) 2009 in Hong Kong. Hong Kong Med J 2012; 18:310-317. [PMID: 22865175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
OBJECTIVE. To investigate the association between population structure and the pandemic influenza A (H1N1) 2009 epidemic in a spatial context. DESIGN. A retrospective case-report series study. SETTING. Hong Kong. PATIENTS. Laboratory-confirmed cases of human influenza A (H1N1) 2009 reported to the Centre for Health Protection between May and September 2009. MAIN OUTCOME MEASURES. A geo-referenced database was established comprising age, gender, and residence location of all influenza A (H1N1) 2009 cases reported in the first 5 months of the Kong Kong epidemic's first wave in 2009. They were divided into four age categories: infant, student, adult, and elderly. Correlation coefficients and odds ratios were calculated to explore the association of H1N1 cases with population configurations in 400 District Council Constituency Areas. RESULTS. Of the 24 414 H1N1 cases reported, students accounted for the highest proportion (54.6%), followed by adults (33.4%), infants (11.1%), and the elderly (0.9%). Transmission was initially concentrated in students which then extended to infants and adults. Except for the elderly, the total population size and that of each age category were significantly associated with the H1N1 cases spatially. Mobility indicators as reflected by the number of students studying outside and adults working outside residential District Council Constituency Areas were also positively associated with H1N1 cases. CONCLUSIONS. Local population structure and mobility were associated with the spatial distribution of the H1N1 epidemic, despite the small size of the territory of Hong Kong. If an influenza epidemic hits again, an examination of these factors spatially would be useful in supporting the planning of interventions.
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Kim ET, Lee SS, Kim HJ, Song JY, Kim CH, Ha JK. Effects of dietary potential Acid production value on productivity in dairy cows. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2012; 25:653-8. [PMID: 25049610 PMCID: PMC4093105 DOI: 10.5713/ajas.2012.12020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 02/21/2012] [Accepted: 02/16/2012] [Indexed: 12/04/2022]
Abstract
This study was conducted to estimate the potential acid production value (PAPV) of major diets and to determine the relationship between dietary PAPV and dairy production traits. Estimation of PAPV of major cattle feeds was based on an in vitro technique, which determined the degree of Ca dissociation from CaCO3. Data on feeds and production traits were collected on 744 multiparous lactating Holstein dairy cows from five different farms. Grains had high PAPV with variable protein sources and by-products. High PAPV feedstuffs had a higher total gas production and lower pH compared to those with low PAPV. Dietary PAPV had a positive correlation with intake of dry matter, NDF, ADF, milk yield and milk solid production but a negative correlation with milk protein and milk fat concentration. Current results indicate that dietary PAPV can be utilized in predicting dairy production traits.
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Pham TNQ, Coffin CS, Churchill ND, Urbanski SJ, Lee SS, Michalak TI. Hepatitis C virus persistence after sustained virological response to antiviral therapy in patients with or without past exposure to hepatitis B virus. J Viral Hepat 2012; 19:103-11. [PMID: 21699630 DOI: 10.1111/j.1365-2893.2011.01442.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hepatitis C virus (HCV) and hepatitis B virus (HBV) frequently coinfect and persist long after clinical resolution. We assessed the incidence of low-level (occult) HCV infection (OCI) after sustained virological response (SVR) to standard anti-HCV therapy in individuals with or without past exposure to HBV to recognize whether HBV could influence the prevalence of OCI, HCV level and hepatic histology. Plasma and peripheral blood mononuclear cells (PBMC) were collected from 24 individuals at 6- to 12-month intervals for up to 72 months after SVR. Liver histology was available for nine patients. HCV and HBV genomes were detected with sensitivity <10 genome copies/mL. In individuals without HBV exposure (n = 15), comprehensive analyses of sequential plasma and PBMC samples revealed HCV RNA in all 15 cases (75% plasma and 61% PBMC). In the group with HBV exposure (n = 9), evidenced by circulating anti-HBc and/or HBV DNA detection by a highly sensitive assay, HCV RNA was identified in all cases (83% plasma and 59% PBMC), at levels similar to those in HBV nonexposed individuals. In both groups of patients, most liver biopsies included those reactive for viral genomes displayed low-grade inflammation (8 of 9) and fibrosis (7 of 9). Sequence polymorphisms at the 5`-UTR between PBMC and liver or plasma, as well as circulating HCV virion-like particles, were observed in patients with or without HBV exposure. In conclusion, the prevalence of OCI after SVR is comparable in individuals with or without past exposure to HBV. HCV loads and liver alterations in OCI appear to be unaffected by low-level HBV DNA carriage.
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Kim YK, Lee SS, Suh EH, Lee L, Lee HC, Lee HJ, Yeon SC. Sprayed intraperitoneal bupivacaine reduces early postoperative pain behavior and biochemical stress response after laparoscopic ovariohysterectomy in dogs. Vet J 2012; 191:188-92. [DOI: 10.1016/j.tvjl.2011.02.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Revised: 12/31/2010] [Accepted: 02/08/2011] [Indexed: 11/17/2022]
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Park SH, Ryu MH, Ryoo BY, Im SA, Kwon HC, Lee SS, Park SR, Kang BY, Kang YK. Sorafenib in patients with metastatic gastrointestinal stromal tumors who failed two or more prior tyrosine kinase inhibitors: a phase II study of Korean gastrointestinal stromal tumors study group. Invest New Drugs 2012; 30:2377-83. [PMID: 22270258 DOI: 10.1007/s10637-012-9795-9] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 01/17/2012] [Indexed: 02/08/2023]
Abstract
PURPOSE To evaluated the efficacy and safety of sorafenib in patients with advanced gastrointestinal stromal tumors (GIST) who failed to previous standard treatments. EXPERIMENTAL DESIGN Thirty-one patients with measurable metastatic GIST who failed both imatinib and sunitinib were accrued. Sorafenib was administered orally at 400 mg twice daily until disease progression or development of intolerance. The primary endpoint was disease control rate (response + stable disease, DCR) at 24 weeks. RESULTS Sorafenib was well tolerated, with hand-foot skin reaction, fatigue, hypertension, and abdominal pain being the most frequent adverse events. The relative dose intensity of sorafenib during the first 6 months was >80%. Four patients achieved partial response (response rate 13%, 95% CI 1-25%), and 16 (52%) had stable disease. DCR at 24 weeks was measured as 36% (95% CI 19-52%). Median progression-free and overall survivals were 4.9 and 9.7 months, respectively. Progression-free survival of patients with prior use of nilotinib (P = .0085) and with primary genotypes other than KIT exon 11 mutation (P = .0341) was significantly shorter than that of patients without. CONCLUSIONS Sorafenib showed antitumor activity in this population of imatinib and sunitinib pretreated GIST. With sorafenib, about one third of patients can maintain disease control for more than 24 weeks.
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Lee SS, Sherman M, Ramji A, Greenbloom S, Elkashab M, Pluta H, Hilzenrat N, Balshaw R, Usaty C, Myers RP. Randomised clinical trial: the efficacy of treatment, guided by a shorter duration of response, using peginterferon alfa-2a plus ribavirin for hepatitis C virus other than genotypes 2 or 3. Aliment Pharmacol Ther 2012; 35:37-47. [PMID: 22050141 DOI: 10.1111/j.1365-2036.2011.04911.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The efficacy of individualised antiviral treatment durations for chronic hepatitis C remains unclear. AIM To evaluate treatment durations based on virological responses at week 4, 8 and 12 of peginterferon alfa-2a plus ribavirin therapy. METHODS Previously untreated patients with HCV genotypes, other than 2 or 3, initiated therapy with peginterferon alfa-2a 180 μg/week plus ribavirin 1000-1400 mg/day. HCV-RNA-negative patients at week 4 rapid virological response (RVR) were randomised to 24 or 48 weeks of treatment; those negative at week 8 were randomised to 36 or 48 weeks; and those who were negative or had a ≥ 2-log drop at week 12 were randomised to 72 or 48 weeks. Sustained virological response (SVR) was defined as undetectable HCV-RNA after 24 weeks of follow-up. RESULTS The study was terminated prematurely due to lagging enrollment. Of 236 patients who started treatment, 195 were randomised at week 4 (n = 50), 8 (n = 61) or 12 (n = 84). Ninety-five per cent of patients had genotype 1. SVR rates were not significantly different between patients randomised to 24 (84%) or 48 weeks (84%) at week 4, to 36 (73%) or 48 weeks (74%) at week 8, or to 48 (49%) or 72 weeks (40%) at week 12. CONCLUSIONS In this predominantly genotype 1 cohort, shortening therapy to 24 weeks in patients with a week-4 response and 36 weeks in those with a week-8 response produced SVR rates that were similar to a 48-week regimen. Lengthening treatment to 72 weeks did not improve SVR rates. Genotype 1 patients with RVR can be treated for 24 weeks.
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Lee S, Lee UY, Han SH, Lee SS. Forensic odontological examination of a 1500 year-old human remain in ancient Korea (Gaya). THE JOURNAL OF FORENSIC ODONTO-STOMATOLOGY 2011; 29:8-13. [PMID: 22717908 PMCID: PMC5734854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Forensic odontological examination was performed on one of the 1500-year old human remains of ancient Korea (Gaya) excavated from a burial site at Songhyeon-dong, Changnyeong, South Korea in April, 2008. The main purpose of the examination was to age estimate the remains and record any dental characteristics to aid full-body reconstruction and life history data collection. Oral and radiographic examinations and metric data collection were conducted. During the oral examination, the following observations were made: dental caries, semi-circular abrasion on the maxillary right lateral incisor and enamel hypoplasia on the left and right canines and first premolars in the mandible. The metric data was similar to that of average metric data of modern Koreans. Age estimation was initially conducted using the degree of dental attrition with methods of Takei and Yun, and was estimated to be approximately 40 years. However, it was observed in the radiographic examination, that the maxillary right second molar, together with the mandibular left and right second and third molars had incompletely developed root apices. The age estimation was then performed using the developmental status of the lower second and third molars. The age was estimated to be approximately 16 years using Lee's method which was consistent with the estimation using forensic anthropology. This case study highlights that the degree of attrition should not be used as a sole indicator for age estimation.
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Weber WP, Barry M, Junqueira MJ, Lee SS, Mazzella AM, Sclafani LM. Initial experiences with a multidisciplinary approach to decreasing the length of hospital stay for patients undergoing unilateral mastectomy. Eur J Surg Oncol 2011; 37:944-9. [PMID: 21893395 DOI: 10.1016/j.ejso.2011.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 08/04/2011] [Accepted: 08/08/2011] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND We hypothesized that the introduction of a short-stay pathway would result in a significant reduction in length of stay for patients undergoing unilateral mastectomy, without a negative impact on patient safety. MATERIALS AND METHODS As part of a quality improvement project, a multidisciplinary committee designed a 1-day stay program for unilateral mastectomy patients. The study period was the first year after the 1-day pathway had routinely been implemented. We report on consecutive patients undergoing unilateral mastectomy ± tissue expander at Memorial Sloan-Kettering Cancer Center from July 1, 2009 to June 30, 2010. The primary endpoint was the percentage of patients discharged on postoperative day 1. Secondary endpoints included the incidence of postoperative complications within 30 days of surgery, reoperations, readmissions, and urgent-care visits within 7 days. RESULTS Over a 12-month period, 537 patients underwent unilateral mastectomy. Of those, 82.7% (444/537) were performed on a 1-day hospitalization basis, compared with 9.6% in 2008, before implementation of the 1-day plan. The 30-day complication rate was 6.1% (33/537). Overall, 2.6% of all patients had reoperation for hematoma (14/537), 0.9% had to be readmitted (5/537), and 1.5% (8/537) attended the urgent-care department. If all patients had stayed in the hospital for more than 1 day, none of the readmissions and only 2 urgent-care visits would have been prevented. CONCLUSIONS This study shows that a 1-day stay following mastectomy is easy to implement and safe for patients if a multidisciplinary team is involved in planning and implementation.
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Lee TH, Park DH, Lee SS, Seo DW, Park SH, Lee SK, Kim MH, Kim SJ. Outcomes of endoscopic transpapillary gallbladder stenting for symptomatic gallbladder diseases: a multicenter prospective follow-up study. Endoscopy 2011; 43:702-8. [PMID: 21425042 DOI: 10.1055/s-0030-1256226] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND STUDY AIMS Endoscopic transpapillary gallbladder drainage for symptomatic gallbladder disease is a safe and effective bridge therapy in patients at high risk for surgery or who have terminal liver disease and are awaiting transplantation. However, there are few reports on long-term results in terms of stent patency and clinical course. Our study was designed to investigate the long-term patency and clinical course after endoscopic transpapillary gallbladder stenting (ETGS) in patients with symptomatic gallbladder disease. PATIENTS AND METHODS A total of 29 patients who were unsuitable for cholecystectomy underwent ETGS from June 2006 to March 2010 using a 7-Fr double-pigtail stent between the gallbladder and the duodenum. Their clinical progress, adverse events, and stent patency after ETGS were recorded prospectively in two tertiary referral centers. RESULTS Technically, ETGS was successful in 23 (79.3%) of the 29 patients. The mean procedure time was 22.4 ± 11.5 min. Postprocedure adverse events were mild pancreatitis (8.7%) and cholestasis (8.7%), all of which resolved with conservative management. During the follow-up period (median 586 days, range 11-1403 days), 20 patients were analyzed as per protocol, and scheduled follow-up was performed. Late adverse events developed in four patients (20%), including distal migration (n = 2), cholangitis (n = 1), and recurrent biliary pain (n = 1). The remaining 16 patients were followed for more than 12 months (nine patients were followed for more than 24 months). Median stent patency was 760 days, as determined by the Kaplan-Meier method. CONCLUSIONS As a primary therapy, ETGS is technically feasible and effective in patients who are unsuitable for cholecystectomy. ETGS may also provide long-term stent patency without the need for scheduled stent exchanges.
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Ke CM, Huang FJ, Lee SS, Chen YS, Hsieh PJ, Lin YE. Use of data mining surveillance system in real time detection and analysis for healthcare-associated infections. BMC Proc 2011. [PMCID: PMC3239661 DOI: 10.1186/1753-6561-5-s6-p235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Lim HT, Zhong T, Cho IC, Seo BY, Kim JH, Lee SS, Ko MS, Park HB, Kim BW, Lee JH, Jeon JT. Novel alternative splicing by exon skipping in KIT associated with whole-body roan in an intercrossed population of Landrace and Korean Native pigs. Anim Genet 2011; 42:451-5. [PMID: 21749430 DOI: 10.1111/j.1365-2052.2011.02225.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The KIT locus has been suggested to be a strong candidate region linked with whole-body roan in the F(2) population produced by intercrosses between Landrace and Korean Native pigs. In this manuscript, we report the finding of a novel alternative splicing event in the porcine KIT gene that results in the skipping of exon 5 in the I(Rn) allele. KIT mRNAs that lack exon 5 were identified in the large intestine and skin, suggesting that the mechanism responsible for the skipping of exon 5 may be tissue specific. A U(26) repeat in intron 5 showed complete linkage (LOD = 11.8) with the roan phenotype and absolute association with the black phenotype of the Korean Native pig (KNP) population samples, inferring that the repeat pattern may alter the complementary base-pairing-mediated looping-out of introns 4 and 5, which may mediate the exon 5-skipping event. Although the sample size in our study was relatively small, we speculate that the R3 allele containing the U(26) repeat is a causative element for the roan phenotype via alternative control of the exon skipping in our roan pedigree.
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Kim SH, Lee BK, Baik J, Jeon C, Lee SS, Lee J, Hwang HN, Hwang CC, Park CY, An KS. In-situ synchrotron radiation photoemission spectroscopy study of the initial atomic layer deposition of Al2O3 film on Si(001) substrate. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2011; 11:4328-4332. [PMID: 21780451 DOI: 10.1166/jnn.2011.3629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In-situ synchrotron radiation photoemission spectroscopy and X-ray photoemission spectroscopy have been used to investigate the initial stages of Al2O3 growth on a Si(001) substrate by atomic layer deposition (ALD). The core level spectra of Si 2p, O 1s, and Al 2p as well as the valence band spectra were measured at every half reaction in the trimethylaluminum (TMA)-H2O ALD process. The line shape changes and binding energy shifts of the core level spectra reveal that Al2O3 is predominantly formed with a small amount of Si oxide in the initial stages without the formation of Al silicate. All core level spectra were alternately shifted toward higher and lower binding energies sides at every half ALD reaction. This can be explained by the band bending effect induced by different chemical species on the surface during the TMA-H2O ALD reaction. The valence band spectra showed that four cycles of ALD reactions were necessary to complete the electronic structure of the Al2O3 film with a valence band offset of 3.73 eV.
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Fenter P, Lee SS, Skelton AA, Cummings PT. Direct and quantitative comparison of pixelated density profiles with high-resolution X-ray reflectivity data. JOURNAL OF SYNCHROTRON RADIATION 2011; 18:257-265. [PMID: 21335914 DOI: 10.1107/s0909049510040422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 10/08/2010] [Indexed: 05/30/2023]
Abstract
A method for comparing pixelated density profiles (e.g. obtained from molecular dynamics or other computational techniques) with experimental X-ray reflectivity data both directly and quantitatively is described. The conditions under which such a comparison can be made quantitatively (e.g. with errors <1%) are determined theoretically by comparing calculated structure factors for an intrinsic continuous density profile with those obtained from density profiles that have been binned into regular spatial increments. The accuracy of the X-ray reflectivity calculations for binned density profiles is defined in terms of the inter-relationships between resolution of the X-ray reflectivity data (i.e. its range in momentum transfer), the chosen bin size and the width of the intrinsic density profile. These factors play a similar role in the application of any structure-factor calculations that involve the use of pixelated density profiles, such as those obtained from iterative phasing algorithms for inverting structures from X-ray reflectivity and coherent diffraction imaging data. Finally, it is shown how simulations of a quartz-water interface can be embedded into an exact description of the `bulk' phases (including the substrate crystal and the fluid water, below and above the actual interface) to quantitatively reproduce the experimental reflectivity data of a solid-liquid interface.
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Choi SA, Lee SS, Jung IH, Kim HA, Byun JH, Lee MG. The effect of gadoxetic acid enhancement on lesion detection and characterisation using T₂ weighted imaging and diffusion weighted imaging of the liver. Br J Radiol 2010; 85:29-36. [PMID: 21123305 DOI: 10.1259/bjr/12929687] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES To evaluate the effect of gadoxetic acid enhancement on the detection and characterisation of focal hepatic lesions on T(2) weighted and diffusion weighted (DW) images. METHODS A total of 63 consecutive patients underwent T(2) weighted and DW imaging before and after gadoxetic acid enhancement. Two blinded readers independently identified all of the focal lesions using a five-point confidence scale and characterised each lesion using a three-point scale: 1, non-solid; 2, indeterminate; and 3, solid. For both T(2) weighted and DW imaging, the accuracies for detecting focal lesions were compared using the free-response receiver operating characteristic analysis; the accuracies for lesion characterisation were compared using the McNemar test between non-enhanced and gadoxetic acid-enhanced image sets. For hepatic lesions ≥ 1 cm, the lesion-to-liver contrast-to-noise ratio (CNR) and the apparent diffusion coefficient (ADC) were compared in the non-enhanced and enhanced image sets using the generalised estimating equations. RESULTS For both T(2) weighted and DW images, the accuracies for detecting focal lesions (p ≥ 0.52) and those for lesion characterisation (p ≥ 0.63) did not differ significantly between the non-enhanced and enhanced image sets. The lesion-to-liver CNR was significantly higher on enhanced DW images than on non-enhanced DW images (p=0.02), although the difference was not significant for T(2) weighted imaging (p=0.65). The mean ADC values of lesions did not differ significantly on enhanced and non-enhanced DW imaging (p=0.75). CONCLUSION The acquisition of T(2) weighted and DW images after administration of gadoxetic acid has no significant effect on the detection or characterisation of focal hepatic lesions, although it improves the lesion-to-liver CNR on DW images.
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Lee SS, Liu E, To KW. Mesenteric fat thickness in a group of HIV patients on HAART. J Int AIDS Soc 2010. [PMCID: PMC3113078 DOI: 10.1186/1758-2652-13-s4-p72] [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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Baek IH, Kang W, Yun HY, Lee SS, Kwon KI. Modelling the atypical absorption of menatetrenone and the metabolism to its epoxide: effect ofVKORC1polymorphism. J Clin Pharm Ther 2010; 36:390-8. [PMID: 21545618 DOI: 10.1111/j.1365-2710.2010.01183.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hong HS, Byun JH, Won HJ, Kim KW, Lee SS, Lee MG, Yun SC. Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement. Clin Radiol 2010; 65:701-7. [PMID: 20696297 DOI: 10.1016/j.crad.2010.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 04/19/2010] [Accepted: 04/25/2010] [Indexed: 11/26/2022]
Abstract
AIM To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. MATERIALS AND METHODS Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. RESULTS There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p>0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. CONCLUSION Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.
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Lee SS, Lee KCK, Tse ICT, Lee MP, Wong KH, Li PCK, Sung JY. Profiling advanced disease in an Asian clinical human immunodeficiency virus cohort: comparison of two definitions for acquired immunodeficiency syndrome. Hong Kong Med J 2010; 16:199-206. [PMID: 20519756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
OBJECTIVE To compare advanced human immunodeficiency virus disease defined immunologically and clinically by evaluating the characteristics of human immunodeficiency virus patients in Hong Kong. DESIGN Retrospective observational study. SETTING A human immunodeficiency virus cohort database established at a university and the major human immunodeficiency virus specialist services in Hong Kong. PATIENTS Patients diagnosed with acquired immunodeficiency syndrome at the study centres between 1985 and 2006 were included. MAIN OUTCOME MEASURES Comparison of advanced human immunodeficiency virus disease defined (a) clinically as World Health Organization stage IV, and (b) immunologically as a CD4 count lower than 350/microL. RESULTS Between 1985 and 2006, a total of 1317 patients, a majority of whom Chinese, were evaluated. Of these, 914 (69%) and 335 (25%) fulfilled the criteria for immunologically and clinically defined advanced disease, respectively. The mean age of the study population was 38 years and male-to-female ratio 4:1. There were two peaks in the frequency distribution of CD4 counts, one at a low count of less than 100/microL and the other between 200 and 400/microL. All except four with clinically defined advanced disease had CD4 counts lower than 350/microL on presentation. Of those with immunologically defined advanced disease, men having sex with men accounted for a lower proportion in the clinically advanced category, and Pneumocystis pneumonia was the commonest advanced disease at presentation. CONCLUSIONS Both clinical and immunological definitions provide a consistent means for assessing advanced disease, the implications of which are different. Such profiling has been made possible through the operation of a standardised cohort database, which is useful in (1) enhancing human immunodeficiency virus epidemiology studies, and (2) evaluating the performance of public health services.
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Pang PTT, Leung CC, Lee SS. Neighbourhood risk factors for tuberculosis in Hong Kong. Int J Tuberc Lung Dis 2010; 14:585-592. [PMID: 20392351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND Tuberculosis (TB) has been reported to be associated with poverty, especially in developing countries. Hong Kong is one of the few industrialised areas with a high incidence of TB where previous reports on the effect of poverty at neighbourhood level have been conflicting. OBJECTIVE To examine the spatial distribution of TB and its association with neighbourhood risk factors. METHOD A total of 17 294 TB cases notified from 2005 to 2007 were mapped down to the District Council Constituency Area (DCCA) level, and were indirectly standardised by age and sex using 2006 census population data. The standardised TB ratio was correlated with neighbourhood risk factors classified by family, ethnicity, economic and environmental domains. RESULTS The indirect age- and sex-standardised ratio demonstrated a spatially varied pattern, and was significantly associated with all neighbourhood factors on univariate analysis. Only marital status, place of birth and low household income were independently associated with the standardised TB ratio on multivariate analysis. CONCLUSION Despite the virtual elimination of absolute poverty by a well-developed social assistance scheme, low household income in the neighbourhood was significantly associated with TB, independently of place of birth, marital status and other risk factors.
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Park DJ, Kim TJ, Lee HJ, Lee KE, Lee SJ, Seo SR, Yoon W, Moon KS, Lee KW, Lee SS, Park YW. De novo appearance of primitive neuroectodermal tumor in a patient with systemic lupus erythematosus and moyamoya disease. Lupus 2010; 19:989-92. [DOI: 10.1177/0961203310364399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Primitive neuroectodermal tumor is a rare brain tumor composed of undifferentiated or poorly differentiated neuroepithelial cells with a high malignant potential that usually occurs in children, and which is only occasionally encountered in adults. A 19-year-old female with systemic lupus erythematosus presented with right hemiparesis and a headache of 10 days duration. Brain magnetic resonance imaging showed a large solid mass with necrotic portions in the left frontoparietal lobe. Primitive neuroectodermal tumor was confirmed by a neuronavigator-guided brain biopsy. This is the first case report of primitive neuroectodermal tumor associated with systemic lupus erythematosus and moyamoya disease. This case demonstrates that brain tumors, such as primitive neuroectodermal tumor, should be included in the differential diagnosis of neurological manifestations in children and adolescent patients with systemic lupus erythematosus.
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Kim YK, Seo EG, Lee SS, Suh EH, Houpt KA, Lee HC, Lee HJ, Yeon SC. Comparative analysis of vocalizations of thoroughbred mares (Equus caballus) between estrus and diestrus. J Vet Med Sci 2010; 72:929-33. [PMID: 20203437 DOI: 10.1292/jvms.09-0430] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the differences between vocalizations of mares in estrus and diestrus and determined the spectrographic parameters to discriminate estrus from diestrus. Thoroughbred brood mares (n=89) were exposed to a teasing procedure for 3 min, and we recorded all vocalizations emitted from them. Among the mares, 56.5% of estrus and 78.6% of diestrus mares emitted calls toward an approaching stallion, indicating that there was higher tendency in the occurrence rate of vocal responses in diestrus than estrus mares. We analyzed the spectrographic data of the mares (25 estrus and 22 diestrus mares) emitting calls in the form of a squeal toward an approaching stallion. Based on broad bandwidth spectrographic analysis, the duration and third formant of the call have a significant effect on discriminating estrus from diestrus.
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