Simulations of liquid-crystal Fabry-Perot etalons by an improved 4X4 matrix method

The optical performances of a liquid crystal (LC) Fabry-Perot (FP) etalon in various configurations were simulated by a faster 4 x 4 matrix method. Results show that the FP with a 90degrees twisted nematic LC is polarization. insensitive if the applied voltage exceeds similar to3X of the Freedericksz transition threshold. This method can well depict the transmission spectra of the FP cavity and, therefore, is useful for optimizing the FP tunable filters for telecommunications

Design Optimization of Broadband Linear Polarization Converter Using Twisted Nematic Liquid Crystal

An optimization method was developed for improving the designs of broadband linear polarization converters using a twisted nematic liquid crystal film and two uniaxial compensation films. As compared to the Poincaré Sphere approach, our optimization method takes the material dispersions into consideration and results in a broader bandwidth. Such a broadband half-wave film is particularly useful for enhancing the light efficiency of liquid crystal display devices

Serum MicroRNA Expression Profile Distinguishes Enterovirus 71 and Coxsackievirus 16 Infections in Patients with Hand-Foot-and-Mouth Disease

Altered circulating microRNA (miRNA) profiles have been noted in patients with microbial infections. We compared host serum miRNA levels in patients with hand-foot-and-mouth disease (HFMD) caused by enterovirus 71 (EV71) and coxsackievirus 16 (CVA16) as well as in other microbial infections and in healthy individuals. Among 664 different miRNAs analyzed using a miRNA array, 102 were up-regulated and 26 were down-regulated in sera of patients with enteroviral infections. Expression levels of ten candidate miRNAs were further evaluated by quantitative real-time PCR assays. A receiver operating characteristic (ROC) curve analysis revealed that six miRNAs (miR-148a, miR-143, miR-324-3p, miR-628-3p, miR-140-5p, and miR-362-3p) were able to discriminate patients with enterovirus infections from healthy controls with area under curve (AUC) values ranged from 0.828 to 0.934. The combined six miRNA using multiple logistic regression analysis provided not only a sensitivity of 97.1% and a specificity of 92.7% but also a unique profile that differentiated enterovirial infections from other microbial infections. Expression levels of five miRNAs (miR-148a, miR-143, miR-324-3p, miR-545, and miR-140-5p) were significantly increased in patients with CVA16 versus those with EV71 (p<0.05). Combination of miR-545, miR-324-3p, and miR-143 possessed a moderate ability to discrimination between CVA16 and EV71 with an AUC value of 0.761. These data indicate that sera from patients with different subtypes of enteroviral infection express unique miRNA profiles. Serum miRNA expression profiles may provide supplemental biomarkers for diagnosing and subtyping enteroviral HFMD infections

Infection status and risk factors of HIV, HBV, HCV, and syphilis among drug users in Guangdong, China - a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>China has witnessed a remarkable increase in sexually transmitted infections (STIs) and HIV. The study is to assess the prevalence of HIV, HBV, HCV and syphilis and related risk factors among drug users in mandatory detoxification center Qingyuan, Guangdong, China.</p> <p>Method</p> <p>A cross-sectional study on drug use behaviors, sex behaviors, and presence of antibodies to HIV, HCV, Treponema pallidum, and surface antigen of HBV (HBsAg) was conducted among drug users recruited from 3 detoxification centers in Qingyuan, Guangdong, China. Risk factors for each of four infections were analyzed with logistic regression model.</p> <p>Results</p> <p>A total of 740 subjects were recruited, the median age was 31 years old (range 24-38). The seroprevalence rates of HIV, HBsAg, HCV and syphilis were 4.6%, 19.3%, 71.6% and 12.6%, respectively. Risk factors for HIV were intravenous drug use and co-infection with syphilis. Having a regular sexual partner who was a drug user was considered to be a risk factor for HBV. Intravenous drug use was a risk factor for HCV. However, the consistent use of condoms with commercial sex partners was protective for HCV infection. Compared to drug users living in urban area, those living in rural areas were more likely to be infected with syphilis, and there was an association between commercial sex and syphilis.</p> <p>Conclusion</p> <p>The prevalence of HIV, HBV, HCV and syphilis were high among drug users in detoxification centers in Qingyuan, thus, risk reduction programs for the drug user population is urgently required.</p

Association of polymorphisms in survivin gene with the risk of hepatocellular carcinoma in Chinese han population: a case control study

<p>Abstract</p> <p>Background</p> <p>Survivin, one of the strongest apoptosis inhibitors, plays a critical role in the development and progression of hepatocellular carcinoma (HCC). By comparison, relatively little is known about the effect of <it>survivin </it>gene polymorphisms on HCC susceptibility. Our study aimed to investigate the association of <it>survivin </it>gene polymorphisms with the risk of HCC in Chinese han population.</p> <p>Methods</p> <p>A case-control study was conducted in Chinese han population consisting of 178 HCC cases and 196 cancer-free controls. Information on demographic data and related risk factors was collected for all subjects. Polymorphisms of the <it>survivin </it>gene, including three loci of rs8073069, rs9904341 and rs1042489, were selected and genotyped by a polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) technique. Association analysis of genotypes/alleles and haplotypes from these loci with the risk of HCC was conducted under different genetic models.</p> <p>Results</p> <p>Using univariate analysis of rs8073069, rs9904341 and rs1042489 under different genetic models, no statistically significant difference was found in genotype or allele distribution of HCC cases relative to the controls (<it>P </it>> 0.05). Linkage disequilibrium (LD) analysis showed that these loci were in LD. Multivariate logistic regression indicated that with no G-C-T haplotype as reference, the haplotype of G-C-T from these loci was associated with a lower risk for HCC under the recessive model (<it>OR = </it>0.46, 95% confidence interval (<it>CI</it>): 0.24~0.90, <it>P </it>= 0.023). Both HBsAg+ and the medical history of viral hepatitis type B were risk factors for HCC. However, no statistically significant haplotype-environment interaction existed.</p> <p>Conclusions</p> <p>No association between rs8073069, rs9904341 or rs1042489 in <it>survivin </it>gene and the risk of HCC is found in Chinese han population, but rs8073069G-rs9904341C- rs1042489T is perhaps a protective haplotype for HCC.</p

Quantitative analysis and comparison of 3D morphology between viable and apoptotic MCF-7 breast cancer cells and characterization of nuclear fragmentation

Morphological changes in apoptotic cells provide essential markers for defining and detection of apoptosis as a fundamental mechanism of cell death. Among these changes, the nuclear fragmentation and condensation have been regarded as the important markers but quantitative characterization of these changes is yet to be achieved. We have acquired confocal image stacks of 206 viable and apoptotic MCF-7 cells stained by three fluorescent dyes. Three-dimensional (3D) parameters were extracted to quantify and compare their differences in morphology. To analyze nuclear fragmentation, a new method has been developed to determine clustering of nuclear voxels in the reconstructed cells due to fluorescence intensity changes in nuclei of apoptotic cells. The results of these studies reveal that the 3D morphological changes in cytoplasm and nuclear membranes in apoptotic cells provide sensitive targets for label-free detection and staging of apoptosis. Furthermore, the clustering analysis and morphological data on nuclear fragmentation are highly useful for derivation of optical cell models and simulation of diffraction images to investigate light scattering by early apoptotic cells, which can lead to future development of label-free and rapid methods of apoptosis assay based on cell morphology.Open Access Fundin

Willingness to Accept HIV Pre-Exposure Prophylaxis among Chinese Men Who Have Sex with Men

OBJECTIVE: We investigated the awareness and acceptability of pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) and potential predicting factors. METHODS: This study was conducted among MSM in Beijing, China. Study participants, randomly selected from an MSM cohort, completed a structured questionnaire, and provided their blood samples to test for HIV infection and syphilis. Univariate logistic regression analyses were performed to evaluate the factors associated with willingness to accept (WTA) PrEP. Factors independently associated with willingness to accept were identified by entering variables into stepwise logistic regression analysis. RESULTS: A total of 152 MSM completed the survey; 11.2% had ever heard of PrEP and 67.8% were willing to accept it. Univariate analysis showed that age, years of education, consistent condom use in the past 6 months, heterosexual behavior in the past 6 months, having ever heard of PrEP and the side effects of antiretroviral drugs, and worry about antiretroviral drugs cost were significantly associated with willingness to accept PrEP. In the multivariate logistic regression model, only consistent condom use in the past 6 months (odds ratio [OR]: 0.31; 95% confidence interval [CI]: 0.13-0.70) and having ever heard of the side effects of antiretroviral drugs (OR: 0.30; 95% CI: 0.14-0.67) were independently associated with willingness to accept PrEP. CONCLUSIONS: The awareness of PrEP in the MSM population was low. Sexual behavioral characteristics and knowledge about ART drugs may have effects on willingness to accept PrEP. Comprehensive prevention strategies should be recommended in the MSM community

Predictors of HIV and Syphilis among Men Who Have Sex with Men in a Chinese Metropolitan City: Comparison of Risks among Students and Non-Students

Men who have sex with men (MSM) are at a substantial risk of HIV, given rising HIV prevalence in urban China. Adolescent and adult students often take HIV-related risk as part of sexual exploration. We compared the risks of HIV and syphilis infections and risky sexual behaviors between student and non-student among urban MSM.Respondent driven sampling approach was used to recruit men who were self-identified as MSM in Chongqing Metropolitan City in southwestern China in 2009. Each participant completed a computer-assisted self-interview which collected demographic and behavioral data, and provided blood specimens for HIV and syphilis testing. Multivariable logistic regression analyses identified predictors for HIV and syphilis infections while comparing student and non-student MSM.Among 503 MSM participants, 36.4% were students, of whom 84.2% were in college. The adjusted prevalence of HIV infection was 5.5% (95% confidence interval [CI]: 2.1%-10.2%) in students and 20.9% (95% CI: 13.7%-27.5%) in non-students; the adjusted prevalence of syphilis was 4.4% (95% CI: 0.7%-9.0%) in students and 7.9% (95% CI: 3.6%-12.9%) in non-students (P = 0.12). Two groups had similar risky sexual behaviors such as number of sexual partners and exchanging sex for money. Multivariate analysis showed that students had lower HIV prevalence than non-students (adjusted odds ratio [AOR]: 0.3; 95% CI: 0.1-0.8) adjusting for age, ethnicity and other variables.Student MSM have lower HIV and similar syphilis prevalence compared with non-student MSM. However, due to a shorter duration of sexual experience and high prevalence of at-risk sexual behaviors among student MSM, HIV risk might be quite high in students as in non-students