Uptake of HIV testing and its correlates among sexually experienced college students in Southwestern, China: a Web-Based online cross-sectional study.

BACKGROUND: The prevalence of human immunodeficiency virus (HIV) is becoming more common among college students in China. However, latest data on the prevalence and correlates of HIV testing among sexually experienced college students is rarely. METHODS: An online survey was conducted among college students aged 18 years or older using multistage stratified cluster sampling from 16 colleges. Data on socio-demographic, HIV testing, HIV-related awareness, attitudes, sexual education and behaviors were collected. Propensity score matching (PSM) and logistic regression model were used to identify factors associated with HIV testing. RESULT: A total of 108,987 students participated the survey, of which 13,201 sexually experienced college students were included in this study. 1,939 (14.69%) college students with sexual experience reported uptake of HIV testing in the preceding year. The uptake of HIV testing increased for college students with a rising HIV knowledge score and sexual health knowledge. Being awareness of HIV-related knowledge (aOR = 1.15, 95%CI: 1.01-1.30), accepting one-night stands (aOR = 1.16, 95%CI:1.03-1.32), obtaining satisfactory sexual interpretation from parent(s) (aOR = 1.24, 95%CI: 1.07-1.43), ever had unintended pregnancy (aOR = 1.78, 95%CI: 1.32-2.38), ever had received HIV-related preventive service(s) (aOR = 1.37, 95%CI: 1.10-1.70), ever had participated HIV-related preventive services (aOR = 3.76, 95%CI: 2.99-4.75) and ever had anal sex (aOR = 2.66, 95%CI: 2.11-3.34) were positively associated with uptake of HIV testing. However, accepting premarital sex (aOR = 0.76, 95%CI: 0.66-0.88), accepting cohabitation (aOR = 0.75, 95%CI: 0.61-0.92), occasionally discussing sex with parent(s) (aOR = 0.68, 95%CI: 0.50-0.91), and being with moderate satisfaction of school sex courses (aOR = 0.74, 95%CI: 0.58-0.95) were negatively associated with uptake of HIV testing. CONCLUSION: The prevalence of HIV testing was relatively low. Participation in HIV-related services and high-risk sexual behaviors were important enablers for testing. Improving sex education for students, increasing HIV preventive services on campus, and improving family sex education are necessary to increase HIV testing among college sexually experienced students.

Reflective structure for phase-shifted fiber Bragg grating.

A novel, to the best of our kowledge, reflective phase-shifted fiber Bragg grating (R-PS-FBG) structure composed of a conventional fiber Bragg grating (FBG) and a micromirror with an air gap between them is proposed. The R-PS-FBG may be regarded as consisting of a Fabry-Perot interferometer and a phase-shifted fiber Bragg grating (PS-FBG), and its reflection and transmission spectra are investigated numerically and experimentally for different mirror reflectances and gap widths. The R-PS-FBG can be implemented easily and could be used in optical spectrum filtering, wavelength tuning, and multiparameter sensing with better sensitivity and resolution.

Deletion of serine racemase reverses neuronal insulin signaling inhibition by amyloid-ß oligomers.

Dysregulation of insulin signaling in the Alzheimer's disease (AD) brain has been extensively reported. Serine racemase (SR) modulates insulin secretion in pancreatic islets. This study aimed to examine whether SR regulates insulin synthesis and secretion in neurons, thereby modulating insulin signaling in the AD brain. Srr-knockout (Srr-/- ) mice generated with the CRISPR/Cas9 technique were used. Using immunofluorescence and fluorescence in situ hybridization, levels of insulin protein and insulin(ins2) mRNA were significantly increased in the hippocampal but not in hypothalamic sections of Srr-/- mice compared with WT mice. Real-time quantitative PCR revealed that ins2 mRNA from primary hippocampal neuronal cultures of Srr-/- mice was significantly increased compared with that from cultured neurons of WT mice. Notably, the secretion of proinsulin C-peptide was increased in Srr-/- neurons relative to WT neurons. By examining membrane fractional proteins with immunoblotting, Srr-/- neurons retained ATP-dependent potassium channels on plasmalemma and correspondingly contained higher levels of p-AMPK. After treatment with Aß42, the phosphorylation levels of insulin receptor substrate at serine 616 636 (p-IRS1ser616,636 ) were significantly lower, whereas p-AKT308 and p-AKT473 were higher in Srr-/- neurons than in WT neurons, respectively. The phosphorylated form of c-Jun N-terminal kinase decreased in the cultured Srr-/- neurons relative to the WT neurons upon Aß42 treatment. In contrast, phosphorylated protein kinase R remained at the same levels. Further, reactive oxygen species were reduced in cultured Srr-/- neurons under Aß42 treatment relative to the WT neurons. Collectively, our study indicated that Srr deletion promoted insulin synthesis and secretion of proinsulin C-peptide, thereby reversing insulin resistance by Aß42. This study suggests that targeting the neuronal SR may be utilized to enhance insulin signaling which is inhibited at the early stage of the AD brain.

PLOD2 promotes aerobic glycolysis and cell progression in colorectal cancer by upregulating HK2.

The purpose of this study was to characterize the expression of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a membrane-bound homodimeric enzyme that specifically hydroxylates lysine in the telopeptide of procollagens, and assess the clinical significance of PLOD2 in colorectal cancer (CRC). Our results show that PLOD2 is highly expressed in CRC tumor tissues and cell lines, both at the mRNA and protein levels. Next, we found that PLOD2 was positively correlated with tumor grade (P = 0.001), T stage (P = 0.001), N stage (P < 0.001), and an advanced TNM stage (P < 0.001). Knockdown of PLOD2 attenuated CRC cell proliferation, migration, and invasiveness, in vitro. Our analysis of the mechanism behind the effects of PLOD2 suggests that PLOD2 affected glycolysis by regulating the expression of hexokinase 2 (HK2). HK2 reverses the inhibitory effects of PLOD2 knockdown in CRC. Furthermore, the data suggest that PLOD2 regulates the expression of HK2 via the STAT3 signaling pathway. Survival analysis revealed that high expression levels of PLOD2 (HR = 3.800, P < 0.001) and HK2 expression (HR = 10.222, P < 0.001) correlated with the overall survival rate. After analyzing their expression and correlation, PLOD2 positively correlated with HK2 (r = 0.590, P < 0.001). Our findings have revealed that PLOD2 is a novel regulatory factor in glucose metabolism, exerted via controlling HK2 expression in CRC cells, suggesting PLOD2 as a promising therapeutic target for CRC treatment.

Practical reflective birefringent fiber interferometer sensor.

This paper proposes a simple and practical reflective birefringent fiber interferometer sensor that consists of a polarization beam splitter, a polarization-maintaining transmission fiber, and a sensor unit comprising two segments of birefringent fibers and a thin-film reflector. This sensor could be used for dual parameter sensing. Experiments with different temperatures and lateral loads applied to the sensor unit demonstrated temperature and load sensitivity of ∼0.0010 nm/°C and 0.298 nm/N, respectively. Further study showed that temperature-insensitive lateral load measurement can be achieved by using equal length of birefringent fibers and performing differential wavelength measurement. The sensor is robust against environmental disturbance on the transmission fiber, making it potentially attractive for practical field applications.

Estimation of gyro bias drift due to distributed polarization cross coupling in the fiber coil.

Distributed polarization cross coupling (PCC) along the polarization-maintaining fiber (PMF), obtained from an optical coherence domain polarimetry (OCDP) system, is analyzed. It is found that the measured PCC data at each measurement location is the sum of the OCDP source coherence function centered at a series of discrete PCC points, which do not represent the true PCC information. An algorithm is developed to extract the "true" location and strength of the PCC and the extracted PCC data are no longer source dependent. A model is developed to relate the extracted PCC data in the PMF coil to the fiber optic gyro (FOG) bias drift due to coherent PCC. Experimental results obtained with a FOG with a ~3 km PMF coil and light sources of different bandwidths agree with the theoretically estimated bias drifts.

Radiation-induced birefringence variations in polarization-maintaining fibers.

Gamma radiation-induced birefringence (RIB) variations in a solid core photonic crystal polarization-maintaining fiber (Pc-PMF) and a Panda PMF (Pa-PMF) are investigated. Experiments show that the birefringence of the fibers changes approximately linearly with a radiation dose over the range from 0 to 400 krad(Si), with negative slope coefficients of 8.91×10-10/krad(Si) and 4.38×10-9/krad(Si) for the Pc-PMF and Pa-PMF, respectively. Models of RIB variations for the two fibers are established, and the theoretical results agree well with the experimental ones.

Femtosecond-laser-inscribed sampled fiber Bragg grating with ultrahigh thermal stability.

We have successfully fabricated a series of sampled fiber Bragg gratings with easily adjustable sampling periods and duty cycles using an 800 nm femtosecond laser point-by-point inscription. The thermal stability of the fabricated fiber gratings was investigated using isochronal annealing tests, which indicated that the fiber gratings are capable of maintaining high reflectivity at temperatures of up to 1000°C for 8 h. This demonstrates the potential of the developed sampled fiber Bragg gratings for use in multi-wavelength fiber lasers and a variety of high temperature applications.

[Theoretical research on a high Q factor elliptical differential photoacoustic resonator].

The sensitivity of photoacoustic (PA) sensors strongly depends on the characteristic of PA cell. In the present paper, a novel elliptical differential PA cell was proposed to enhance the signal noise ratio of PA system. An acoustic characteristic mathematic model was built and the acoustic characteristic of PA cell was simulated with COMSOL software. The result shows that peak pressures would occur at the two ends of major axis with a pi phase difference when the mixed modes in the cross section of elliptical cell have odd azimuthal nodes along the minor axis. When the half major axis is less than 4 cm, the resonant frequency could be greater than 10kHz and the Q factor could achieve 1 835. Differential detection of PA signal could be realized and the common mode environment noise would be suppressed effectively. The signal noise ratio can be enhanced and high sensitivity detection could be achieved with this high Q factor elliptical differential cell.

Fabry-Perot interferometer based Mie Doppler lidar for low tropospheric wind observation.

Similar in principle to recent implementations of a lidar system at 355 nm [Opt. Lett. 25, 1231 (2000), Appl. Opt. 44, 6023 (2005)], an incoherent-detection Mie Doppler wind lidar at 1064 nm was developed and deployed in 2005 [Opt. Rev. 12, 409 (2005)] for wind measurements in the low troposphere, taking advantage of aerosol scattering for signal enhancement. We present a number of improvements made to the original 1064 nm system to increase its robustness for long-period operation. These include a multimode fiber for receiving the reference signal, a mode scrambler to allow uniform illumination over the Fabry-Perot interferometer, and a fast scannable Fabry-Perot interferometer for calibration and for the determination of outgoing laser frequency during the wind observation. With these improvements in stability, the standard deviation of peak transmission and FWHM of the Fabry-Perot interferometer was determined to be 0.49% and 0.36%, respectively. The lidar wind measurements were validated within a dynamic range of +/-40 m/s. Comparison experiments with both wind profiler radar and Vaisala wiresonde show good agreement with expected observation error. An example of 24 h continuous observations of wind field and aerosol backscatter coefficients in the boundary layer with 1 min and 30 m temporal and spatial resolution and 3 m/s tolerated wind velocity error is presented and fully demonstrates the stability and robustness of this lidar.