Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures.

The irregular morphology of single rock fracture significantly influences subsurface fluid flow and gives rise to a complex and unsteady flow state that typically cannot be appropriately described using simple laws. Yet the fluid flow in rough fractures of underground rock is poorly understood. Here we present a numerical method and experimental measurements to probe the effect of fracture roughness on the properties of fluid flow in fractured rock. We develop a series of fracture models with various degrees of roughness characterized by fractal dimensions that are based on the Weierstrass-Mandelbrot fractal function. The Lattice Boltzmann Method (LBM), a discrete numerical algorithm, is employed for characterizing the complex unsteady non-Darcy flow through the single rough fractures and validated by experimental observations under the same conditions. Comparison indicates that the LBM effectively characterizes the unsteady non-Darcy flow in single rough fractures. Our LBM model predicts experimental measurements of unsteady fluid flow through single rough fractures with great satisfactory, but significant deviation is obtained from the conventional cubic law, showing the superiority of LBM models of single rough fractures

Male Clients of Male Sex Workers in China: An Ignored High-Risk Population.

BackgroundThere is a high prevalence of HIV/syphilis among male sex workers, but no formal study has ever been conducted focusing on male clients of male sex workers (MCM). A detailed investigation was thus called for, to determine the burden and sociobehavioral determinants of HIV and syphilis among these MCM in China.MethodsAs part of a multicenter cross-sectional study, using respondent-driven and snowball sampling, 2958 consenting adult men who have sex with men (MSM) were recruited, interviewed, and tested for HIV and syphilis between 2008 and 2009. The distributions of sociodemographic characteristics, risk behaviors, and HIV/syphilis prevalence were determined and compared between MCM and other MSM.ResultsAmong recruited MSM, 5.0% (n = 148) were MCM. HIV prevalences for MCM and other MSM were 7.4% and 7.7%, whereas 18.9% and 14.0% were positive for syphilis, respectively. Condomless anal intercourse (CAI) was reported by 59.5% of MCM and 48.2% of MSM. Multiple logistic regression revealed that compared with other MSM, MCM were more likely to have less education [for ≤ elementary level, adjusted odds ratio (aOR) = 3.13, 95% confidence interval (95% CI): 1.42 to 6.90], higher income (for >500 US Dollars per month, aOR = 2.97, 95% CI: 1.53 to 5.77), more often found partners at parks/restrooms (aOR = 4.01, 95% CI: 2.34 to 6.85), reported CAI (aOR = 1.49, 95% CI: 1.05 to 2.10), reported a larger sexual network (for ≥ 10, aOR = 2.70, 95% CI: 1.44 to 5.07), and higher odds of syphilis (aOR = 1.54, 95% CI: 1.00 to 2.38).ConclusionsThe greater frequency of risk behaviors and high prevalence of HIV and syphilis indicated that HIV/syphilis prevention programs in China need to pay special attention to MCM as a distinct subgroup, which was completely ignored until date

On effects of regular S=1 dilution of S=1/2 antiferromagnetic Heisenberg chains by a quantum Monte Carlo simulation

The effects of regular S=1 dilution of S=1/2 isotropic antiferromagnetic chain are investigated by the quantum Monte Carlo loop/cluster algorithm. Our numerical results show that there are two kinds of ground-state phases which alternate with the variation of $S^1=1$ concentration. When the effective spin of a unit cell is half-integer, the ground state is ferrimagnetic with gapless energy spectrum and the magnetism becomes weaker with decreasing of the $S^1$ concentration $\rho = 1/M$. While it is integer, a non-magnetic ground state with gaped spectrum emerges and the gap gradually becomes narrowed as fitted by a relation of $\Delta \approx 1.25\sqrt{\rho}$.Comment: 6 pages, 9 figure

CMM : an enhanced platform for interactive validation of metal binding sites

Abstract Metal ions bound to macromolecules play an integral role in many cellular processes. They can directly participate in catalytic mechanisms or be essential for the structural integrity of proteins and nucleic acids. However, their unique nature in macromolecules can make them difficult to model and refine, and a substantial portion of metal ions in the PDB are misidentified or poorly refined. CheckMyMetal (CMM) is a validation tool that has gained widespread acceptance as an essential tool for researchers working on metal-macromolecule complexes. CMM can be used during structure determination or to validate metal binding sites in structural models within the PDB. The functionalities of CMM have recently been greatly enhanced and provide researchers with additional information that can guide modeling decisions. The new version of CMM shows metals in the context of electron density maps and allows for on-the-fly refinement of metal binding sites. The improvements should increase the reproducibility of biomedical research. The web server is available at https://cmm.minorlab.org

Induction of CCL8/MCP-2 by mycobacteria through the activation of TLR2/PI3K/Akt signaling pathway.

Pleural tuberculosis (TB), together with lymphatic TB, constitutes more than half of all extrapulmonary cases. Pleural effusions (PEs) in TB are representative of lymphocytic PEs which are dominated by T cells. However, the mechanism underlying T lymphocytes homing and accumulation in PEs is still incompletely understood. Here we performed a comparative analysis of cytokine abundance in PEs from TB patients and non-TB patients by protein array analysis and observed that MCP-2/CCL8 is highly expressed in the TB-PEs as compared to peripheral blood. Meanwhile, we observed that CCR5, the primary receptor used by MCP-2/CCL8, is mostly expressed on pleural CD4(+) T lymphocytes. Furthermore, we found that infection with either Mycobacterium bovis Bacillus Calmette-Guérin (BCG) or Mycobacterium tuberculosis H37Rv induced production of MCP-2/CCL8 at both transcriptional and protein level in Raw264.7 and THP-1 macrophage cells, mouse peritoneal macrophages as well as human PBMC monocyte-derived macrophages (MDMs). The induction of MCP-2/CCL8 by mycobacteria is dependent on the activation of TLR2/PI3K/Akt and p38 signaling pathway. We conclude that accumulation of MCP-2/CCL8 in TB-PEs may function as a biomarker for TB diagnosis

Transgender sexual health in China: a cross-sectional online survey in China

Transgender individuals are at increased risk for HIV infection around the world, yet few studies have focused on transgender individuals in China. We conducted an online cross-sectional survey of men who have sex with men (MSM) and transgender individuals to examine sociodemographics, intimate partner violence (IPV) and sexual behaviours in China

Condom use social norms and self-efficacy with different kinds of male partners among Chinese men who have sex with men: results from an online survey

Abstract Background Social norms and self-efficacy play important roles in promoting consistent condom use among men who have sex with men (MSM). Few studies have investigated the association between social norms, self-efficacy and consistent condom use with different kinds of male partners among MSM. We conducted an online survey of MSM to evaluate this in China. Methods A cross-sectional online survey was conducted in 2015. Participants completed a validated questionnaire covering socio-demographic information, consistent condom use, condom use social norms and self-efficacy. Eligible participants were 16 or older, born biologically as a male, engaged in anal sex with a man at least once during their lifetime, engaged in condomless anal or vaginal sex in the last three months. In this study, we further restricted to people who had sex with male partners in the last three months. Participants were classified into three groups: engaged in sex only with regular partners, engaged in sex only with casual partners and engaged in sex with both regular partners and casual partners. Results Participants were recruited from 32 provinces in China. Among 1057 participants, 451(42.7%), 217(20.5%), and 389(36.8%) engaged in sex with regular partners only, casual partners only and both types in the last three months, respectively. Men engaged in sex only with regular partners in the last three months had a higher condom use self-efficacy than with other two types of partners (P  0.05). Conclusions Both social norms and self-efficacy were positively correlated with consistent condom use with any types of partners among Chinese MSM. Tailored interventions that aimed to improve social norms and self-efficacy has the potential to improve overall condom use among Chinese MSM. Trial registration ClinicalTrials.gov: NCT02516930 . August 6, 2015

Condom use social norms and self-efficacy with different kinds of male partners among Chinese men who have sex with men: results from an online survey.

BACKGROUND: Social norms and self-efficacy play important roles in promoting consistent condom use among men who have sex with men (MSM). Few studies have investigated the association between social norms, self-efficacy and consistent condom use with different kinds of male partners among MSM. We conducted an online survey of MSM to evaluate this in China. METHODS: A cross-sectional online survey was conducted in 2015. Participants completed a validated questionnaire covering socio-demographic information, consistent condom use, condom use social norms and self-efficacy. Eligible participants were 16 or older, born biologically as a male, engaged in anal sex with a man at least once during their lifetime, engaged in condomless anal or vaginal sex in the last three months. In this study, we further restricted to people who had sex with male partners in the last three months. Participants were classified into three groups: engaged in sex only with regular partners, engaged in sex only with casual partners and engaged in sex with both regular partners and casual partners. RESULTS: Participants were recruited from 32 provinces in China. Among 1057 participants, 451(42.7%), 217(20.5%), and 389(36.8%) engaged in sex with regular partners only, casual partners only and both types in the last three months, respectively. Men engaged in sex only with regular partners in the last three months had a higher condom use self-efficacy than with other two types of partners (P  0.05). CONCLUSIONS: Both social norms and self-efficacy were positively correlated with consistent condom use with any types of partners among Chinese MSM. Tailored interventions that aimed to improve social norms and self-efficacy has the potential to improve overall condom use among Chinese MSM. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02516930 . August 6, 2015

MSM HIV testing following an online testing intervention in China.

BACKGROUND: Scaling up HIV testing is the first step in the HIV treatment continuum which is important for controlling the HIV epidemic among men who have sex with men (MSM). Following an online HIV testing intervention among MSM, we aim to examine sociodemographic and spatial factors associated with HIV testing. METHODS: We conducted a secondary analysis on data from an online HIV testing intervention among MSM who had never-tested for HIV. The survey was distributed through online networks connected to all provinces and regions of China. Univariate and multivariable analyses were performed to examine factors associated with testing three weeks post-intervention. RESULTS: At three weeks after the intervention, 36% of 624 followed-up MSM underwent HIV testing, 69 men reported positive HIV test results. Having money for sex, ever tested for sexually transmitted infections and intimate partner violence experience were significant factors of post-intervention HIV testing. Students were less likely to undergo HIV testing at follow-up compared to others (adjusted odds ratio=0.69, 95% C.I.=0.47-0.99), adjusted by age and type of intervention. Moderate provincial spatial variation of testing was observed. CONCLUSIONS: While high risk men generally had higher HIV testing rates, some MSM like students had lower testing rates, suggesting the need for further ways to enhance HIV testing in specific MSM communities