Knowledge, attitudes, and practices toward coronavirus and associated anxiety symptoms among university students : a cross-sectional study during the early stages of the COVID-19 pandemic in Bangladesh

Background: University students’ knowledge, attitude, and practice (KAP) toward COVID-19 are vital to prevent the spread of the virus, especially in the context of developing countries. Consequently, the present study aimed to determine the KAP levels of university students and associated anxiety during the earlier stage of the pandemic in Bangladesh. Methods: A cross-sectional, online study with 544 university students was conducted during April 17–May 1, 2020. The questionnaire incorporated several KAP-related test items aligned with the World Health Organization (WHO) guidelines. Anxiety was measured with the 2-item Generalized Anxiety Disorder scale (GAD-2). Multivariable logistic regression analysis was performed to determine the association between KAP levels and anxiety adjusting for sociodemographic variables. Subgroup analyses included rerunning models stratified by gender and quarantine status. Results: Approximately 50% of students showed high levels of knowledge about COVID-19 guidelines, 59% reported behavioral practices that aligned with COVID-19 guidelines, and 39% had negative attitudes toward COVID-19 guidelines. Attitudes differed by anxiety (χ2 = 23.55, p < 0.001); specifically, negative attitudes were associated with higher anxiety (OR: 2.40, 95% CI = 1.66–3.46, p < 0.001). Associations were significant for male (OR = 2.36; 95% CI = 1.45–3.84, p < 0.001) and female (OR = 2.45; 95% CI = 1.3–4.34; p < 0.001) students. Stratified analyses found non-quarantined students with negative attitudes had three times the chance of experiencing anxiety (OR = 3.14, 95% CI: 1.98–4.98, p < 0.001). Non-quarantined students with low levels of knowledge had half the chance of developing anxiety (OR = 0.49, 95% CI: 0.31–0.78, p < 0.01). Conclusion: Based on these findings, it is recommended that university authorities continue to prioritize proactive and effective measures to develop higher levels of knowledge, more positive attitudes and better behavioral practices regarding COVID-19 for the mental health of their students

Hemocompatibility of Silicon-Based Substrates for Biomedical Implant Applications

Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories—coagulation (thrombin–antithrombin complex, TAT generation), complement activation (complement protein, C3a production), platelet activation (P-selectin, CD62P expression), and platelet adhesion. Our tests revealed that all silicon substrates display low coagulation and complement activation, comparable to that of Teflon and stainless steel, two materials commonly used in medical implants, and significantly lower than that of diethylaminoethyl (DEAE) cellulose, a polymer used in dialysis membranes. Unmodified silicon and polysilicon showed significant platelet attachment; however, the surface modifications on silicon reduced platelet adhesion and activation to levels comparable to that on Teflon. These results suggest that surface-modified silicon substrates are viable for the development of miniaturized renal replacement systems

Walkability and greenness do not walk together: Investigating associations between greenness and walkability in a large metropolitan city context

Background: The existing environment literature separately emphasizes the importance of neighborhood walkability and greenness in enhancing health and wellbeing. Thus, a desirable neighborhood should ideally be green and walkable at the same time. Yet, limited research exists on the prevalence of such “sweet spot” neighborhoods. We sought to investigate this question in the context of a large metropolitan city (i.e., Sydney) in Australia. Methods: Using suburb level normalized difference vegetative index (NDVI), percentage urban greenspace, Walk Score® (Walk Score, Seattle, USA), and other data, we explored the global and local relationships of neighborhood-level greenness, urban green space (percent park area) with walkability applying both nonspatial and spatial modeling. Results: We found an overall negative relationship between walkability and greenness (measured as NDVI). Most neighborhoods (represented by suburbs) in Sydney are either walkable or green, but not both. Sweet spot neighborhoods that did exist were green but only somewhat walkable. In addition, many neighborhoods were both less green and somewhat walkable. Moreover, we observed a significant positive relationship between percentage park area and walkability. These results indicate walkability and greenness have inverse and, at best, mixed associations in the Sydney metropolitan area. Conclusions: Our analysis indicates an overall negative relationship between greenness and walkability, with significant local variability. With ongoing efforts towards greening Sydney and improving walkability, more neighborhoods may eventually be transformed into becoming greener and more walkable

Urban green space and health in low and middle-income countries: A critical review

2020 Elsevier GmbH Studies from high income, mostly westernised countries tend to report health benefits from urban green spaces. Generalizability of this evidence for the 125 low and middle-income countries (LMICs) is debatable. This systematic review explored and synthesized the quality of green space-health studies reported from LMICs. Following PRISMA guidelines, 22 studies were found through a systematic search and after applying inclusion criteria by two researchers. Quantitative and qualitative synthesis of these studies included a study quality assessment using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. The 22 studies were conducted in 11 LMICs and mostly of the cross-sectional design. Health outcomes include mental and physical health, wellbeing. Green space and health outcomes were mostly measured by the subjective tool, such as by the perception of the sample population; most reporting green space benefits except the study conducted on a slum population and two studies measured physical health outcomes. Only 14 studies adjusted different moderating variables in the quantitative analysis. Three studies explored mediation analyses and reported physical activity and perceived restorativeness of UGS to be the strongest potential pathways to better health. Lack of adherence to observation study design protocols resulted in the studies to have moderate to low quality. The enquiry on the potential health benefits of green space in LMICs is an important gap in knowledge. The evidence in the LMICs is limited by the quality of the studies. More research, especially longitudinal studies that make use of objective indicators of green space design, utilisation and health indicators in a wider range of LMICs is warranted

Young gravel-pit lakes along Canada’s Dempster Highway: How do they compare with natural lakes?

Gravel-pit lakes are a common feature of many human-modified landscapes throughout the world. In Canada’s north, they are often formed when gravel is extracted to construct dams, bridges, and highways. Past studies suggest that gravel-pit lakes differ from natural lakes in terms of their morphometry, water quality, and biological communities. In this study, we compared gravel-pit and natural lakes by sampling lakes between Inuvik and Fort McPherson in the Northwest Territories. We collected lake morphometry, water quality, and biological data (zooplankton, macroinvertebrates, and fish presence) from six gravel-pit lakes and fifteen natural lakes. In comparison to natural lakes, gravel-pit lakes were four times deeper, two times clearer, and five times smaller in their surface area. In addition, important nutrients, including phosphorus and nitrogen, were significantly lower in gravel-pit lakes. Despite the differences in morphometry and nutrients, pelagic zooplankton and littoral macroinvertebrate communities did not differ significantly between the two lake types. Therefore, we conclude that despite their recent formation and unnatural morphometry, gravel-pit lakes along the Dempster Highway can support invertebrate communities typical of natural lakes in the region

Investigation of a reliable and sustainable stand-alone hybrid energy system for freshwater supply: a case study

Hybrid renewable energy system-based reverse osmosis desalination has been identified as a reliable and sustainable solution for supplying potable water to the off-grid communities. In this respect, this study proposes a stand-alone hybrid energy system comprising solar PV, wind turbine, diesel generator, and a battery bank to power a reverse osmosis desalination plant. The proposed hybrid system is optimised using a novel metaheuristic optimisation technique named salp swarm algorithm (SSA) to minimise the three objective functions: levelised cost of energy (LCOE, $/kWh), life cycle emissions (LCE, CO2 kg-eq/yr.), and the excess energy (EE, kWh/yr.). Moreover, the performance of the novel algorithm is scrutinised using the benchmark solutions achieved from the widely utilised non-dominated sorting genetic algorithm II (NSGA-II) and particle swarm optimisation (PSO) techniques. In addition, the study also investigates the effects of water demand and the loss of power supply probability on the techno-economic performance. The results reveal that SSA outperforms NSGA-II and PSO algorithms towards achieving Pareto optimality hence provides financially rewarding solutions. The LCOE for the optimal HES is 0.179$/kWh, and the LCE is 5921 CO2 kg-eq/yr. with an EE of 402 kWh/yr., whereas the cost of water for this system is 1.37 $/m3

Objective and subjective measures of neighborhood environment (NE): Relationships with transportation physical activity among older persons

10.1186/s12966-015-0276-3International Journal of Behavioral Nutrition and Physical Activity12110