Effect of turbulence-induced sediment resuspension and sedimentation on underwater wireless optical communication.

In real-life marine environments, the composition and grain size of suspended sediments and the resuspension and sedimentation of sediments caused by turbulence may have a significant impact on underwater wireless optical communication (UWOC). However, to date, researchers have not conducted quantitative research on this issue. To this end, we innovatively study the effects of different compositions and grain sizes of suspended sediments on UWOC and the effects of turbulence-induced sediment resuspension and sedimentation on UWOC in this paper. Quartz and kaolin with different grain sizes are used to simulate sediments in seawater. An oscillating grid that can vary frequency and stroke is used to generate turbulence of different intensities. By comparing the turbidity and optical power density of different simulated sediments with different grain sizes, we find that the smaller the grain size of the simulated sediments, the higher the bit error rate (BER) under the same turbidity. But different simulated sediments with different grain sizes have similar effects on BER performance under the same optical power density. Therefore, turbidity can be used to characterize the changes of underwater channels, and optical power density can be used to evaluate the attenuation of light at the receiving end after transmission through the underwater channel. By continuously changing the frequency of the grid to cause the sediments to resuspend and sink, we prove that the process of turbulence-induced sediment resuspension and sedimentation can seriously affect the BER performance. The larger the frequency of the grid, the greater the turbulence intensity and the worse the BER performance. This study lays a foundation for the practical application of UWOC in mobile ocean observation networks.

A green and facile direct ink writing technique for preparation calibration standards in laser ablation inductively coupled plasma mass spectrometry analysis.

BACKGROUND: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful tool for microanalysis of solid materials. Nevertheless, one limitation of the method is the lack of well-characterized homogeneous reference materials (RMs), such as BaF2 crystal and BaCO3 ceramics samples, making direct quantification difficult. This work presents a novel Direct Ink Writing (DIW) method to produce RMs for microanalysis. The Mg, Cr, Fe, Co, Ni, Cu, Y, Mo, Pr, Gd, Dy, Ho, Er, Tm, Yb, and Lu solutions were gravimetrically doped into BaCO3 by mixing with the dispersant and then cured with DIW techniques. (94) RESULTS: BaCO3 powder was combined with a dopant analyte to produce a printable slurry, aided by the use of a dispersant and cellulose. The resulting mixture was then printed using DIW equipment. The retention rates of the doped elements were investigated by internal and external standard method, and the results showed that they were completely dispersed in the solid material. After further optimization, it was found that there was no significant heterogeneity among the printed samples. LA-ICP-MS was used to analyze printed samples, to evaluate micro-scale homogeneity. The mass concentration of the doped element was determined by ICP-MS, verify its move closer to nominal value. Compared with the traditional reference materials preparation methods, the DIW technology greatly increased the sample homogeneity and the accuracy of the desired concentration. (132) SIGNIFICANCE: As far as we know, there are few reports on the application of DIW method to prepare calibration standards. In brief, it is proved that the proposed method of preparing calibration standard by DIW technique to quantify analytes is valid and robust. This procedure provides great potential for LA-ICP-MS in-situ analysis in the field of well-prepared products, such as ceramic and crystal samples.(63).

In situ quantitative yttrium and trace elements imaging analysis of Y-doped BaF2 crystals by LA-ICP-MS.

In this study, a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method for in-situ determination of yttrium and trace elements in yttrium-doped barium fluoride (BaF2: Y) crystals was proposed. A facile, micro-damage procedure for quantifying the segregation coefficient of doping elements was investigated, and it was found that the actual yttrium doping concentration increases from the seed end to the tail end in BaF2: Y crystals. In micro-area analysis, this method has higher mass sensitivity which was applied to quantify the impurity content and distribution during the growth of BaF2: Y crystals. Regression coefficient of calibration curve for each element ranged from 0.9918 to 0.9995. Detection limits (DLs) were 0.05, 0.03, 0.01 and 0.01 µg g-1 for Mg, Zn, Sr and Pb, respectively. The accuracy of the proposed method was verified by inductively coupled plasma mass spectrometry/atomic emission spectroscopy (ICP-MS/AES) with wet-chemical pretreatment. The objective of the presented work was to provide a less damaging and more novelty approach for crystal sample analysis.

Semi-Automated Quantitative Evaluation of Neuron Developmental Morphology In Vitro Using the Change-Point Test.

Neuron morphology gives rise to distinct axons and dendrites and plays an essential role in neuronal functionality and circuit dynamics. In rat hippocampal neurons, morphological development occurs over roughly one week in vitro. This development has been qualitatively described as occurring in 5 stages. Still, there is a need to quantify cell growth to monitor cell culture health, understand cell responses to sensory cues, and compare experimental results and computational growth model predictions. To address this need, embryonic rat hippocampal neurons were observed in vitro over six days, and their processes were quantified using both standard morphometrics (degree, number of neurites, total length, and tortuosity) and new metrics (distance between change points, relative turning angle, and the number of change points) based on the Change-Point Test to track changes in path trajectories. Of the standard morphometrics, the total length of neurites per cell and the number of endpoints were significantly different between 0.5, 1.5, and 4 days in vitro, which are typically associated with Stages 2-4. Using the Change-Point Test, the number of change points and the average distance between change points per cell were also significantly different between those key time points. This work highlights key quantitative characteristics, both among common and novel morphometrics, that can describe neuron development in vitro and provides a foundation for analyzing directional changes in neurite growth for future studies.

Anti-hyperlipidemic and ameliorative effects of chickpea starch and resistant starch in mice with high fat diet induced obesity are associated with their multi-scale structural characteristics.

Chickpea starches were isolated from both untreated (UC-S) and conventionally cooked seeds (CC-S), and their multi-scale structural characteristics and in vivo physiological effects on controlling hyperlipidemia in high fat diet induced obese mice were compared with their corresponding resistant starch (RS) fractions obtained by an in vitro enzymatic isolation method (UC-RS and CC-RS). The degree of order/degree of double helix in Fourier transform infrared spectroscopy was in the following order: CC-RS > UC-RS > CC-S > UC-S, which was consistent with the trend observed for relative crystallinity and double helix contents monitored by X-ray diffractometer and solid-state 13C cross-polarization and magic angle spinning NMR analyses. The influence of different types of chickpea starch and their corresponding resistant starch fractions on regulating the serum lipid profile, antioxidant status, and histopathological changes in liver, colon and cecal tissues, and gene expressions associated with lipid metabolism, gut microbiota, as well as short-chain fatty acid metabolites in mice with high fat diet induced obesity was investigated. The results showed that the chickpea RS diet group exhibited overall better anti-hyperlipidemic and ameliorative effects than those of the starch group, and such effects were most pronounced in the CC-RS intervention group. After a six-week period of administration with chickpea starch and RS diets, mice in the UC-RS and CC-RS groups tended to have relatively significantly higher levels (P < 0.05) of butyric acid in their fecal contents. The 16S rRNA sequencing results revealed that mice fed with CC-RS showed the greatest abundance of Akkermansia and Lactobacillus compared with the other groups.

Evolution of marine litter governance policies in China: Review, performance and prospects.

This study aims to empirically analyze the current situation of marine litter governance in China and unearth methods for future development. Based on a mix of 171 policy documents, this article traces the evolution of marine litter governance policies in China since 1982, using the method of literature analysis and content analysis and ROSTCM6 software. These policies can be divided into three stages: the initial establishment stage (1982-1989), the rapid development stage (1990-1999) and the comprehensive development stage (2000-2020). In each period, the characteristics and performances of policies are analyzed. Key findings demonstrate that policy subjects and tools have been gradually diversified, the content and scope of governance have become broader, and the policy focus has shifted from quantity reduction to green, intelligent and high-quality development. The development of future marine litter governance policy should improve the legal system, focus on technology, and establish a comprehensive management mechanism for land and sea coordination.

Structural rearrangement of native and processed pea starches following simulated digestion in vitro and fermentation characteristics of their resistant starch residues using human fecal inoculum.

Pea starches, in both native (NPS) and retrograded-autoclaved forms (RAPS), were subjected to simulated gastrointestinal (GI) digestion in vitro, their multi-scale structural characteristics, morphological features, molecular distribution and thermal properties were characterized. A gradual increase in the short-/long-range crystallinity, melting enthalpy of gelatinization on increasing digestion time was observed for both the native and retrograded-autoclaved pea starch samples based on the X-ray diffraction, Fourier-transform infrared spectra, solid-state 13CNMR and differential scanning calorimetry measurements. It was especially noticed that the growth rate of crystallinity and double helices, as well as the decrease in Mw values were evidently greater for RAPS than for NPS. To investigate how different molecular fine structure of pea starch substrate affects the gut microbiota shifts and dynamic short-chain fatty acid profile, their resistant starch residues obtained from both native and retrograded-autoclaved pea starch after 8 h of simulated GI tract digestion was used as the fermentation substrate. The levels of acetate, propionate and butyrate gradually increased with the increasing fermentation time for NPS and RAPS. In comparison to the blank control (i.e., the group without the addition of carbohydrate), the fermented NPS and RAPS obviously resulted in an increased abundance of Firmicutes and Bacteroidetes, accompanied by a decrease in Proteobacteria, Actinobacteria and Verrucomicrobia. Both NPS and RAPS promoted different shifts in the microbial community at the genus level, with an increase in the abundance of Bacteroides, Megamonas and Bifidobacterium, as well as a reduction in the abundance of Fusobacterium, Faecalibacterium and Lachnoclostridium in comparison to the blank control samples.

Age-Period-Cohort Analysis of HIV Mortality in China: Data from the Global Burden of Disease Study 2016.

The aim of this study was to investigate the long-term trends of human immunodeficiency virus (HIV) mortality in China and its associations with age, period and birth cohort. We used HIV mortality data obtained from the Global Burden of Disease Study (GBD) 2016 and analysed the data with an age-period-cohort framework. Age effects indicate different risks of different outcomes at specific periods in life; period effects reflect population- wide exposure at a circumscribed point in time; and cohort effects generally reflect differences in risk across birth cohorts.Our results showed that the overall annual percentage change (net drift) of HIV mortality was 11.3% (95% CI: 11.0% to 11.6%) for males and 7.2% (95% CI: 7.0% to 7.5%) for females, and the annual percentage changes in each age group (local drift) were greater than 5% (p < 0.01 for all) in both sexes. In the same birth cohort, the risk of death from HIV increased with age in both sexes after controlling for period effects, and the risk for each five-year period was 1.98 for males and 1.57 for females compared to their previous life stage. Compared to the period of 2002-2006, the relative risk (RR) of HIV mortality in 2012-2016 increased by 56.1% in males and 3.7% in females, and compared to the 1955-1959 birth cohort, the cohort RRs increased markedly, by 82.9 times in males and 34.8 times in females. Considering the rapidly increasing risk of HIV mortality, Chinese policymakers should take immediate measures to target the key age group of 15-44 years in both sexes.

Comprehensive AIDS prevention ability of young students who is men have sex with men and associated factors / 中国学校卫生

Objective@#To understand the characteristics of KAP (knowledge, attitude and practice) related to the prevention of AIDS among young male MSM (man sex with man) in China, and to evaluate the comprehensive ability of AIDS prevention and associated factors to provide a scientific basis for the development of MSM AIDS prevention and control.@*Methods@#From November to December 2019, sampling was recruited by using snowball sampling methods centered on Beijing and Tianjin. A cross-sectional survey of 222 young students MSM was conducted through an online questionnaire with information of general demographic characteristics, sexual behavior and HIV testing, psychological status and comprehensive ability to prevent AIDS.@*Results@#Average score on comprehensive AIDS prevention knowledge was (87.64±6.41),with knowledge,attitude,and behavior score of (11.32±1.67)(54.87±3.36) and (52.18±4.30) respectively.The pass rate of knowledge, attitude, practice related to AIDS prevention were respectively 95.5%, 56.3%, and 27.0%. The separation rate of knowledge from belief was 42.8%, the separation rate of knowledge from behavior was 71.2%, and the separation rate of faith from information was 48.2%. Whether have received AIDS prevention education was related to knowledge qualification rate (P<0.01).@*Conclusion@#Current AIDS education is associated with the knowledge level of AIDS prevention among young MSM groups, but it is not enough to improve their attitudes and behaviors. The comprehensive ability of MSM in preventing AIDS among young students is still not optimistic. Intervention measures need to be further strengthened to improve the comprehensive ability of young students MSM group to prevent AIDS.

Development of the Evaluation Scale for the Comprehensive Ability of HIV/AIDS prevention among Chinese young students / 中国学校卫生

Objective@#To develop the Evaluation Sacle for the Comprehensive Ability of HIV/AIDS prevention among Chinese Young Students(hereinafter referred to as the Evaluation Scale).@*Methods@#The Evaluation Scale was preliminarily developed according to standardized preparation procedures of the scales. Firstly, the item pool of the Evaluation Scale was established via literature review and group discussions, and based on the Fourteen Core knowledge of young students HIV/AIDS prevention and control formulated by the Chinese Center for Disease Control and Prevention. Secondly, the Evaluation Scale was preliminarily formed via using the Delphi method to select items.@*Results@#The Evaluation Scale with 85 items was finally formed including four vertical dimensions of knowledge, attitude, behavior and skills and four horizontal dimensions of hazard, prevention, detection and treatment, laws and regulations via literature research, group discussion and two rounds of Delphi method.@*Conclusion@#The Evaluation Scale developed in this paper is scientific and reasonable for constructing is assumed to be a scientific and reasonable proxy tool for the evaluation of the comprehensive ability of young students to prevent AIDS. It can be used for AIDS prevention education or effect assessment before and after intervention.

Association between the characteristics of sexual partners and substance use before sexual behavior in young male students who have sex with men / 中国学校卫生

Objective@#To understand the characteristics of sexual partners and the influence of having multiple sexual partners on substance use among young male students man who have sex with men (MSM) in China, and to provide scientific basis for the prevention and control of HIV/AIDS among young MSM students.@*Methods@#A mixed recruitment method of snowball sampling and respondent driven sampling was used to recruit young MSM students in Beijing and Tianjin, and a questionnaire survey was conducted among 220 participants from November to December 2019. Chi-square test and generalized linear model multi-factor Logistic regression were used to analyze the influencing factors of substance use before sexual behavior.@*Results@#The average age of them was (22.39±2.57) years old, 84.5% of them were students, the average age of first sexual behavior was (18.83±2.45) years old, 44.1% of them had two or more sexual partners (including fixed sexual partners, temporary sexual partners and commercial sexual partners), 22.7% had more than one male fixed partner. After adjusting for age and education, having multiple sexual partners was risk factor for drinking alcohol before sex (aOR=2.97) or substance abuse (aOR=2.39). Having male temporary sexual partner was an risk factor in substance use before sexual behavior(OR=4.10).@*Conclusion@#The characteristics of sexual partners among young MSM students are complex, and the proportion of multiple sexual partners is high. Having fixed single sexual partner can reduce the risk of substance use before sexual behavior. AIDS prevention education for young MSM students should be further strengthened.

Effect of peer intervention by popular opinion leaders among young students who have sex with men / 中国学校卫生

Objective@#The proposal of this study is to determine the feasibility of using online social software to guide popular opinion leaders(POLs) among young students MSM (men who have sex with men, MSM) carrying out comprehensive AIDS prevention in young students MSM.@*Methods@#From November to December 2019 in Tianjin, 22 POLs who had previously experienced AIDS prevention education and training foucus on life skills were recruited. Though snowball sampling method, 100 POLs partners (friends, sexual partners, classmates, etc) were invited into the study. From January to March 2020, regular posters will be sent through the WeChat platform to guide POL to intervene their partners/sexual partners. The questionnaire surveys were conducted before and after the intervention.@*Results@#After the intervention, both the proportion of young students MSM had sex and with multiple sex partners decreased(χ2=12.12, 5.94, P<0.05). The comprehensive ability of AIDS prevention has improved significantly, the "National Eight Items" correct rate has risen from 90.0% to 99.0%(χ2=5.82, 7.56, P<0.05), and the "Youth Eight Items" correct rate has increased from 86.0% to 98.0%(P<0.01). Knowledge score increased from(11.08±1.89) to (11.84±1.27); Attitude score increased from (54.29±4.01) to (56.06±3.75), the behavior score increased from (52.12±4.78) to (55.08±4.25), skill score increased from (51.96±4.75) to (54.67±5.04), The comprehensive prevention ability score (percent) increased from (87.30±6.95) to (91.86±5.42)(t=-4.21, -3.51, -5.32, -5.16, -6.45, P<0.01).@*Conclusion@#Using Wechat platform to guide POL carrying out comprehensive AIDS prevention is effective for improving the comprehensive AIDS prevention ability of young students MSM.

Association between ego-centric social network and HIV status of MSM young students / 中国学校卫生

Objective@#To identify the characteristics of social network and the association between ego-centric network and HIV status among young MSM Chinese students.@*Methods@#The cross-sectional study was conducted in Chongqing, Tianjin, Harbin and Xi an city from April to December 2017 and from March to May 2018. A mixed recruitment method of snowball sampling and RDS approach was used to recruit participants who reported information on social network and received HIV test. The Multiple Regression Analysis method was used to for the analysis of association between ego-centric social network and HIV status of men who have sex with men (MSM) among young students.@*Results@#The sample included 547 participants who nominated 1 088 social partners in total with average age of 13 to 60 years old. The MSM with different sexual orientation from their social members (aOR=0.38), embedded in a large network (aOR=0.63), with a high individual betweenness centrality (aOR=0.27) were at lower risk of HIV-positive status; while MSM who differed greatly in education level with their social members(aOR=1.60), existed in sexual networks(aOR=1.41), existed in the “risky networks” (aOR=1.88) , with high network density (aOR=1.91) and a high individual degree (aOR=4.10) had higher risk of HIV-positive status(P<0.05).@*Conclusion@#MSM with great difference in education level from social members, existed in sexual networks, with a large network density and a high degree were exposed to higher risk of HIV-positive status.

Secular trends in HIV/AIDS mortality in China from 1990 to 2016: Gender disparities.

OBJECTIVES: HIV/AIDS has become the leading cause of death by infectious disease in China since 2009. However, the trend of gender disparities in HIV/AIDS has not been reported in China since 1990. Our study aimed to explore the secular trend of HIV/AIDS mortality in China from 1990 to 2016 and to identify its gender disparities over the past 27 years. METHOD: The mortality data of HIV/AIDS were obtained from the Global Burden of Disease Study 2016 (GBD 2016). Logistic regression was used to estimate the prevalence odds ratio (POR) of gender for HIV/AIDS mortality in different surveys. RESULTS: The standardized mortality of HIV/AIDS in China rose dramatically from 0.33 per 100,000 people in 1990 to 2.50 per 100,000 people in 2016. The rate of HIV/AIDS mortality increased more quickly in men than in women, and the sex gap of mortality of HIV/AIDS widened. By 2016, the HIV/AIDS mortality in men was 3 times that in women and was 5.74 times that in women within the 75- to 79-year-old age group. CONCLUSIONS: The mortality of HIV/AIDS in China is increasing, with a widening gender disparity. It is critical for policymakers to develop policies to eliminate these disparities and to ensure that everyone can live a long life in full health.

HIV knowledge and high-risk sexual behaviors of men who have sex with men in college students / 中国学校卫生

Objective@#To understand HIV knowledge and high-risk sexual behaviors among men who have sex with men (MSM) in the HIV-infected students’ social network, and to provide a scentific reference of making targeted and effective measures.@*Methods@#A mixed recruitment method of snowball sampling and respondent driven sampling was used to recruit HIV-infected students with the help of local CDC in Harbin, Tianjin, Xi’an and Chongqing, with demographic information, sexual behaviors and HIV knowledge collected via questionnaire survey.@*Results@#A total of 549 valid questionnaires were analyzed. Among them, the awareness rate of "Guo Ba Tiao" was 90.7% and the awareness rate of "Qing Ba Tiao" was 89.4%, the consistent condom use rate was 59.4%. Among those who were aware of HIV, 40.8% exhibit the mismatch between HIV knowledge and condom use behavior, which was significantly associated with number and types of sex partners. Those who had 1-3 regular male sex partners (1 partner: aOR=2.48, 95%CI=1.61-3.82; 2-3 partners: aOR=2.45，95%CI=1.44-4.15),or 1-3 causal male sex partners (1 partner: a-OR=1.74, 95%CI=1.10-2.77; 2-3 partners: aOR=2.15, 95%CI=1.34-3.46) were more likely for this mismatch. Those who had more than one commercial male sex partner(aOR=3.35, 95%CI=1.15-9.80), or more than one regular female sex partner (aOR=2.49, 95%CI=1.17-5.28), or more than one casual female sex partner(OR=2.80, 95%CI=1.01-7.71), the risk for this mismatch was also high.@*Conclusion@#The mismatch between HIV knowledge and condom use behavior among MSM students from the social network of young students living with HIV/AIDS is severe. It is necessary to carry out tailored HIV intervention to reduce the transmission of HIV among those people.

Preliminary exploration and evaluation of POL intervention in young students at high-risk of AIDS / 中国学校卫生

Objective@#Explore the feasibility of POL intervention based on life skills in young students at high-risk of AIDS, and to provide reference for POL intervention.@*Methods@#Nine potential POLs were recruited from young students at high risk of AIDS in Xi’an, and received life-skill-based interventions from May to October in 2017. A unified approach was adopted before the intervention. The effect of intervention was evaluated at 1 month and 3 months after the intervention.@*Results@#The difference in POLs peer status and psychosocial ability scores was not significant after the intervention. The scores of persistence efficacy dimension of condom use efficacy before, 1-month and 3-month after the intervention were (10.56±1.88)(11.11±2.21)(12.89±2.09)(F=6.84, P<0.05) respectively. No significant changes were found in AIDS-related knowledge and behavior before and after the intervention. POL has increased from 108 students before intervention to 216 publicity coverage after three months intervention, however, the difference was not statistically significant. Feasibility analysis of the POL intervention showed that 8 of the POLs considered to be "very useful".@*Conclusion@#Life skill-based POL intervention for young students at high-risk of AIDS has a wide coverage and reasonable acceptance, as well as condom use adherence. The long-term effectiveness still needs to be verified.

Evaluation of immediate effectiveness of intervention on HIV prevention and leadership of POL among young male students who have sex with men in a city / 中国学校卫生

Objective@#To evaluate the immediate effectiveness of intervention on HIV prevention and leadership of POL among young male students who have sex with men in a city, and to provide reference for health education of AIDS.@*Methods@#A life-skills based participatory approach was adopted to intervene the AIDS prevention and leadership of 54 POL in young male students who have sex with men in a city. A unified questionnaire was adopted before and after the intervention to investigate and evaluate the effects.@*Results@#After intervention, the scores of AIDS prevention information increased from (36.30±7.30) points to (42.09±3.43) points (P<0.01). In terms of motivation, the scores of experience and attitude of condom-using were increased from (5.43±1.19) points to (5.83±1.24) points (P<0.05). As for the behavioral skills, the scores of condom-use skills increased from (4.30±1.04) points to (4.85±0.53) points (P<0.01), the scores of condom self-efficacy increased from (55.85±12.40) points to (61.48±8.01) points (P<0.01), the scores of autonomic HIV testing ability increased from (4.11±1.09) points to (4.65±0.52) points (P<0.01), the ability to avoid alcohol consumption before sexual behavior increased from (3.74±1.19) points to (4.13±0.91) points(P<0.05), and the ability to correctly seek medical advice after illness increased from (9.33±1.32) points to (9.69±0.77) points(P<0.05). In the part of the leadership, the scores of peer status increased from (26.96±5.55) points to (29.81±6.68) points (P<0.01), the scores of active communication ability increased from (21.35±5.76) points to (24.43±4.17) points (P<0.01), and the scores of psychosocial ability increased from (77.96±13.42) points to (80.89±12.42) points (P<0.05).@*Conclusion@#Life-skill-based intervention, which is guided by Information-Motivation-Behavioral skills model, is effective in improving AIDS prevention and leadership.