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The transmission network can enhance its economic advantages by adjusting the topology of the power system during operation. However, the constant change in demand requires the switching process to take place continuously during the day. Therefore, this requires the line switching must follow a certain strategy to ensure the stability of the system, such as how often and how long a line can be online/offline. Furthermore, it must refer to thermal power units, which require strict compliance with the start-up and shut-down stages. As a result, this research proposes a model for Multi-period optimal transmission switching in conjunction with the trajectory operation of thermal units to minimize total operating costs in one day. The model is implemented by Mixed Integer Linear Programming (MIP) with binary variables representing the state of the transmission line and thermal unit aiming to sets the switching strategy of the line and configure the trajectory of the thermal unit commitment. The IEEE 118-bus test case is analyzed for 24-hours simulation. The optimal transmission switching results in reduced total operation cost, but the thermal unit's impact must be considered. Eventually, the limitations of the paper are presented for further research.

Honghong Wang,1,* Simin Yu,1,* Wendy Cross,2 Louisa Lam,2 Biswajit Banik,2 Kaili Zhang3 1Xiangya School of Nursing, Central South University, Changsha City, 410000, Hunan Province, People’s Republic of China; 2School of Health, Federation University, Berwick, 3806, Victoria, Australia; 3School of Nursing, Xuzhou Medical University, Xuzhou City, 221004, Jiangsu Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Kaili ZhangNursing School of Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, People’s Republic of ChinaTel/ Fax +86-516-83262165Email xiaokai20060@xzhmu.edu.cnBackground: College student men who have sex with men (MSM) are at high risk for HIV infection due to multiple social and behavioral factors. Consistent condom use is nationally advocated for HIV prevention. This study explored the sexual behaviors and factors associated with condom use consistency in the past six months among college student MSM from seven colleges in Hunan Province, China.Methods: A cross-sectional survey was conducted from September 2017 to March 2018. Condom use consistency, sexual behaviors, HIV testing performance, substance use, and alcohol consumption were examined using researcher-created questionnaires. Condom use self-efficacy and HIV-related knowledge were assessed using the Condom Use Self-Efficacy Scale and the unified National AIDS Sentinel Surveillance Questionnaire. Univariate and multivariate logistic regressions were used. P < 0.05 was considered significant.Results: In the 214 respondents, the rate of consistent condom use was 56% (n = 119) during the past six months. Participants who were studying at first-tier universities (odds ratio [OR]: 2.522, 95% confidence interval [CI]: 1.255– 5.067) and had higher scores for condom use self-efficacy (OR: 2.617, 95% CI: 1.462– 4.685) were more likely to report consistent condom use than the others. The risk factor was having suspicious symptoms of sexually transmitted diseases (OR: 0.357, 95% CI: 0.163– 0.780).Conclusion: Numerous students were at high risk of HIV infection with inconsistent condom use. Comprehensive and specific topics about safe sex education from parents and peers should be offered on campuses in China.Keywords: college student men who have sex with men, condom use consistency, sexual behaviors, sex education

Yufang Guo,1,2 Xinxin Wang,2 Virginia Plummer,3– 5 Wendy Cross,5 Louisa Lam,5,6 Shuangshuang Wang2 1School of Nursing and Rehabilitation, Shandong University, Jinan, Shandong, 250012, People’s Republic of China; 2School of Nursing, Hebei University, Baoding, Hebei, 07100, People’s Republic of China; 3School of Nursing and Midwifery, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, 3199, Australia; 4Peninsula Health, Frankston, Melbourne, Victoria, Australia; 5School of Health, Federation University Australia, Berwick, Victoria, 3806, Australia; 6School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, 3806, AustraliaCorrespondence: Yufang GuoSchool of Nursing and Rehabilitation, Shandong University, 44 Wen Hua Xi Road, Jinan, 250012, Shandong, People’s Republic of ChinaEmail cdguoyufang@163.comBackground: Voice behavior, referred to as a positive guarantee for organizational development, is influenced by several kinds of individual, collective and organizational features. However, the impact of individual competence on voice behavior is unclear. The aim of the present study was to investigate the status quo of core competence and voice behavior of clinical nurses and explore the impact of core competence on nurses’ voice behavior.Methods: A multicenter cross-sectional survey. A total of 1717 nurses were recruited from nine tertiary and secondary hospitals between March and June 2019. An online questionnaire, including socio-demographic variables, employee voice behavior scale and competence inventory for registered nurses, was used to investigate prohibitive and promotive voice behavior and core competence of clinical nurses. Pearson correlation and hierarchical multiple regression were performed in the data analysis.Results: The mean score for prohibitive and promotive voice behavior of nurses were 3.46 (SD 0.77) and 3.46 (SD 0.88), respectively. The mean score for core competence was 2.46 (SD 0.77). Critical thinking/research aptitude was the most important predictor for both prohibitive and promotive voice behavior (each p < 0.05), but its influence on promotive voice behavior was greater (p < 0.05). Leadership was another significant predictor for prohibitive voice behavior (p < 0.05). Legal/ethical practice, teaching-coaching, professional development and shift work were other predictors for promotive voice behavior (each p < 0.05).Conclusion: Clinical nurses experience modest levels of prohibitive and promotive voice behavior and their core competence is moderate. Core competence, especially critical thinking/research aptitude, impacts significantly on voice behavior of clinical nurses. Cultivating nurses’ core competence could positively increase their voice behavior for organizational development.Keywords: clinical site, core competence, cross-sectional survey, nurse, voice behavior

Objective: To investigate the antibiofilm activity of alpha- mangostin (AMG) loaded nanoparticle (nanoAMG) against dental caries pathogen Streptococcus mutans. Methods: AMG was isolated from the peels of Garcinia mangostana L. using silica gel columns and chemically analysed by high performance liquid chromatography and nuclear magnetic resonance. NanoAMG was prepared using the solvent evaporation method combined with high-speed homogenization. The nanoparticles were characterized using dynamic light scattering, field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). The toxicity of nanoAMG in fibroblast NIH/3T3 cell line was determined using MTT method. The antibiofilm effect of nanoAMG was determined through the evaluation of biofilm formation by Streptococcus mutans using a 96-well plate. Biofilm biomass was quantified using crystal violet. Cell viability was observed under confocal microscopy using LIVE/DEAD BacLight staining. Moreover, gene expression was determined by quantitative real-time PCR and membrane permeabilization activity by measuring the uptake of o-nitrophenol- β-D-galactoside. Results: NanoAMG size was in a range of 10-50 nm with a polydispersity index of < 0.3 and zeta potential value of -35.2 mV The size and the incorporation of AMG in the nanoparticles were confirmed by FE-SEM and FTIR analyses. The IC50 values of the test agents on NIH/3T3 cells were (9.80 ± 0.63) μg/mL for AMG and (8.70 ± 0.81) μg/mL for nanoAMG, while no toxicity was generated from excipients used to prepare nanoparticles. In the early stage of biofilm formation, treatment with 6.25 μmol/L nanoAMG caused a reduction in biofilm biomass up to 49.1%, compared to 33.4% for AMG. In contrast, biofilms at the late stage were more resistant to the test agents. At 96 μmol/L (= 10 × MIC), nanoAMG reduced only 20.7% of biofilm biomass while AMG did not show any effect. Expressions of gtfB and gtfC genes involved in biofilm formation were down-regulated 3.3 and 12.5 folds, respectively, compared to AMG (2.4 and 7.6 folds, respectively). LIVE/DEAD BacLight fluorescence staining and microscopy observation indicated that biofilm cells were killed by both nanoAMG and AMG at 48 μmol/L (= 5 × MIC). In addition, membrane permeabilization activity was increased in a time dependent manner and higher in nanoAMG treated cells compared to AMG. Conclusions: AMG coated nanoparticle can enhance AMG bioactivity and can be used as a new and promising antibiofilm agent.

Mache Tsadik,1 Lul Lam,2 Zinabu Hadush11School of Public Health, College of Health Science, Mekelle University, Tigray, Ethiopia; 2Department of Disease Prevention and Control, Gambella Regional Health Bureau, EthiopiaCorrespondence: Mache TsadikSchool of Public Health, College of Health Science, Mekelle University, Tigray, EthiopiaTel +251 91 474 3841Email adhana2008@gmail.comBackground: Delayed health care seeking is one of the major impediments to successfully prevent and control sexually transmitted infections (STIs) including HIV. Gambella is one of the HIV hot spot areas and the most HIV prevalent region in the country. Considering the empirical knowledge of the link between STIs and HIV, gathering information on health-seeking behavior and the associated factors among STI patients is helpful to design interventions that enhance early seeking and treatment adherence.Methodology: A facility-based cross-sectional study was employed to collect data from 424 STI patients from February 15 to April 15, 2017, using a face-to-face interview. A consecutive sampling method was used until the allocated sample for each facility was fulfilled. A multivariate logistic regression analysis was used to identify factors associated with health-seeking behavior.Results: The proportion of delayed health care seeking among patients treated for STIs was 56.8%. Knowledge, number of sexual partners, and perception variables were found significantly associated with early seeking behavior in multivariate logistic regression: patients who had better knowledge of STIs (AOR =1.74, 95% CI =1.10, 2.73), had single sexual partner (AOR =1.83, 95% CI =1.19, 2.78), those who perceived stigma for STIs (AOR =0.52, 95% CI =0.34, 0.79), and perceived severity of STIs (AOR =1.97, 95% CI =1.18, 3.29).Conclusion: This study reported a high proportion of delayed health care seeking. This may challenge the prevention and control effort and alarms the potential threat to the spread of STI/HIV in the region. Provision of intensive health education is crucial to improve awareness and to avoid risk behaviors and negative perceptions.Keywords: health, seeking, behavior, sexually, transmitted, infection, Gambella

We prove that cocompact arithmetic lattices in a simple Lie group are uniformly discrete if and only if Salem numbers are uniformly bounded away from 1. We also prove an analogous result for semisimple Lie groups. Finally, we shed some light on the structure of the bottom of the length spectrum of an arithmetic orbifold \Gamma \backslash X by showing the existence of a positive constant \delta (X)>0 such that squares of lengths of closed geodesics shorter than \delta must be pairwise linearly dependent over \mathbb {Q}. [ABSTRACT FROM AUTHOR]