Search

In the present study, a series of tests were conducted on a purpose-built experimental setup to investigate the relationship between the pressure signal and flow regime in horizontal pneumatic conveying processes. The pressure signals and images of the material flow regime during the conveying process were collected and analyzed. Direct observation, power spectrum analysis, and discrete wavelet transform were employed in this work. The results show that as the conveying pressure increases, the time taken to reach the steady conveying stage is shorter. A correlation was discovered among the frequency intervals, pneumatic conveying stages, and flow regimes. The periodicity of the decomposed signal increases with decomposition scale. [ABSTRACT FROM AUTHOR]

Distributed photovoltaic (PV) output exhibits strong stochasticity and weak adjustability. After being integrated with the network, its interaction with stochastic loads increases the difficulty of assessing the distribution network's static voltage stability (SVS). In response to this issue, this article presents a probabilistic assessment method for SVS in a distribution network with distributed PV that considers the bilateral uncertainties and correlations on the source and load sides. The probabilistic models for the uncertain variables are established, with the correlation between stochastic variables described using the Copula function. The three-point estimate method (3PEM) based on the Nataf transformation is used to generate correlated samples. Continuous power flow (CPF) calculations are then performed on these samples to obtain the system's critical voltage stability state. The distribution curves of critical voltage and load margin index (LMI) are fitted using Cornish-Fisher series. Finally, the utility function is introduced to establish the degree of risk of voltage instability under different scenarios, and the SVS assessment of the distribution network is completed. The IEEE 33-node distribution system is utilized to test the method presented, and the results across various scenarios highlight the method's effectiveness. [ABSTRACT FROM AUTHOR]

Bioplastic films with excellent barrier properties were successfully prepared from poly(butylene adipate‐co‐terephthalate) (PBAT), thermoplastic starch (TPS), and poly((R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyhexanoate) (PHBHHx). The rheological, mechanical, barrier, dynamic mechanical properties, and microstructure of the PBAT/TPS/PHBHHx films were studied. The transition of the continuous phase in the blend significantly affects the properties of the films. The increase in PHBHHx content results in its transition from a dispersed phase to a continuous phase. This phase transition, along with the consequent increase in the crystallinity of PHBHHx, greatly enhances the barrier properties of the film. The percentage crystalline degree of PHBHHx increased from 10.9% to 25.1% with increasing PHBHHx content from 0% to 50%. The film containing 50% PHBHHx showed a significant decrease in both water vapor permeability (WVP) and oxygen permeability (OP) by 75.1% and 69.6%, respectively. It found that the film containing 50% PHBHHx exhibited a decrease of elongation at break from 505% to less than 10% but an unusual increase of tensile strength after a 72‐hour aging test, which is different from PBAT and PBAT/TPS films. However, this indicates that the extensibility of PHBHHx is more susceptible to the effects of aging test, leading to the rearrangement of polymer chains from disordered to ordered morphology. [ABSTRACT FROM AUTHOR]

BackgroundThe World Health Organization recommended HIV self-testing (HIVST) for individuals practicing unsafe sexual behaviors; however, the adherence to HIV testing has not been reported. ObjectiveIn this study, we attempted to determine the adherence to HIVST among men who have sex with men (MSM), as well as the impact factors and potential effects of their adherence. MethodsWe conducted a longitudinal study among MSM in Harbin, Heilongjiang province, China from July 1, 2017 to June 30, 2018. A mobile app system was used to provide the “Mailing rapid test reagent kit” for the HIVST service. The proportion of those who adhered to HIV testing every 3 months was calculated. Logistic regression was used to explore the impact factors related to adherence to HIVST. Rates of HIV infection between MSM who adhered to HIVST and those who did not were compared using Cox proportional hazards regression. Changes of condom use behaviors between the two groups were also compared using the chi-square test. ResultsA total of 1315 MSM who received the HIVST service through the app were included in the study. Overall, 10% of the MSM adhered to HIVST, and the proportion of adhering tests was only 34.9%. Adherence of HIVST was associated with marital status (adjusted odds ratio [OR]unmarried vs married 2.31, 95% CI 1.13-4.71) and the number of HIV tests they received (adjusted OR3 times vs 2 times or below 3.36, 95% CI 2.01-5.63; adjusted OR4 times or above vs 2 times or below 7.30, 95% CI 4.67-11.42). Twenty HIV seroconversions were observed during 1-year follow up. The rate of HIV infection in the adherence group (17.10 per 100 person years, 95% CI 8.80-30.84) was significantly higher than that in the nonadherence group (4.80 per 100 person years, 95% CI 2.77-7.88; adjusted hazard ratio 3.33, 95% CI 1.35-8.20). Those who adhered to HIV testing were more likely to improve condom use behaviors, although the difference was not statistically significant. ConclusionsRegular HIV testing is necessary for early detection of HIV infection among MSM. Given the poor adherence, a new internet-based management paradigm for MSM is needed to raise their health awareness to optimize the implementation of HIVST.

BackgroundTraditional partner notification methods have been implemented for HIV-infected patients, as well as HIV treatment, in order to identify people at risk of HIV infection, especially men who have sex with men (MSM), since they are more likely to have casual sex partners. These traditional methods have some limitations. ObjectiveOur study focused on developing an mHealth app to improve partner notification in practice for MSM; the study then focused on evaluating the effects of the app. MethodsWe developed an mHealth app with different modules using Java and HTML5 and tested it in an MSM community to prevent HIV transmission. The HIV incidence stratified by different follow-up periods were calculated. Poisson regression and social networks were used to estimate the risk ratios and to identify the connection among MSM, respectively. ResultsIn addition to the partner notification module, which is the kernel of the app, we developed a test result self-query module to enable MSM to get their approved test results in a timely manner, a prompt and warning module to alert users to protect themselves from high-risk conditions, and a health education module to teach users more skills regarding HIV/AIDS prevention. Over a 1-year duration, a total of 3186 MSM used the app, of which 678 had at least two HIV test results since becoming app users; they were included in the final analysis. Among 678 users, a total of 6473 self-queries and 623 partner notifications were recorded, which identified 180 social networks of MSM app users. Those who used the partner notification function were more likely to have self-queries (P5 months vs ≤5 months: 2.22 per 100 person-years vs 6.99 per 100 person-years; risk ratio 0.32, 95% CI 0.12- 0.87). ConclusionsThe app developed in this study is consistent with the World Health Organization’s sensitivity and confidentiality recommendations; it has the potential to reduce the risk of HIV infection among MSM.

In this study, a novel environment‐friendly PBST/PPC‐based blown film was prepared using maleic anhydride (MA) as a reactive compatibilizer to enhance the compatibility between poly(butylene succinate‐co‐terephthalate) (PBST) and poly(propylene carbonate) (PPC). Results of rheological testing and gel permeation chromatography (GPC) indicated that MA reacted with PBST/PPC during melt‐blending extrusion. Morphological analysis of the cryo‐fractured surfaces of PBST/PPC blend showed significantly improved compatibility between PBST and PPC with the addition of MA. Moreover, the Young's modulus, tensile strength, breaking strain, and tear strength of PBST/PPC/MA blown films increased with an increase in MA content. In comparison to PBST/MA blown film without PPC, the barrier property of PBST/PPC/MA blown films was improved. In addition, in vitro cell experiments showed that the PBST/PPC/MA blown film was suitable for the growth of mouse fibroblast (L929) cells. In vitro ecotoxicity testing on mung bean plant showed that the extracts from the PBST/PPC/MA blown film had no negative effects on the development of mung bean plant. Furthermore, degradability testing in soil also proved that the PBST/PPC/MA blown film had good biodegradability. Thus, the PBST/PPC/MA blown film can be used in fields, such as food packaging and agricultural mulch film. [ABSTRACT FROM AUTHOR]

Development and regeneration in biological tissues are fundamentally affected by stem‐cell‐fate commitment. Bioelectricity is heterogeneous between different tissues and crucially regulates cell behaviors, including cell differentiation. However, the effects of heterogeneous bioelectricity on stem‐cell differentiation remain poorly understood. Herein, it is shown that providing stem cells with electrical stimulation matching the endogenous membrane potentials of cells derived from different tissues (osteogenic‐related: −55.05 ± 4.22 mV, neurogenic‐related: −84.8 ± 7.48 mV) can induce their osteogenic or neurogenic lineage commitment. Molecular dynamics simulations indicated that the osteogenic‐related surface potential favors the adsorption of fibronectin, while the neurogenic‐related surface potential enhances the adsorption of FGF‐2. These different protein adsorptions trigger either downstream Wnt or Erk signaling, which direct stem‐cell differentiation. Surface‐potential‐mediated lineage‐specification of stem cells using bioelectrical intensity has enormous potential application value in tissue regenerative therapy. [ABSTRACT FROM AUTHOR]