306 research outputs found

    Investigation of potential toxic effects of construction waste runoff collected from illegal dumping site using brine shrimp and zebrafish models

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    Urbanization results in the increment of construction waste, which eventually contaminate the surrounding environment and affects the ecosystem. This study aimed to investigate the potential toxic effects of construction waste runoff collected from an illegal construction waste dumping site, Kampung Sungai Pelong, Malaysia by using brine shrimp (Artemia sp.) and zebrafish (Danio rerio). The runoff sample collected in January 2018 proceeded with the physicochemical test, heavy metal analysis and bio-toxicity study. Several physicochemical properties (BOD, TSS, NH3-N and NO3-) and heavy metal content (Cu>Cd>Ni>As>Pb>Cr>Hg) of runoff had values significantly exceeding the respective Class IIA Malaysia National Water Quality Standards. No mortality and abnormal swimming behaviour were observed for brine shrimp acute assay, but severely damage appendages and pigmentation were evident. In the zebrafish sub-acute assay, no constant trend of mortality was observed, but abnormal swimming pattern and alterations in gill tissue (cell vacuolation and clubbed tips). The results signify the potential eco-toxicity caused by construction waste runoff and urge the need for long-term toxicity study and strict legislative actions by the local authority

    Acute toxicity and teratogenic impacts of construction waste runoff on zebrafish embryo

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    Construction waste is on rise in developing country; heavy metals in construction waste may harm environment and residents. The aim of this research was to study the toxicity and teratogenicity of construction waste runoff by using zebrqfish embryo. The heavy metal analysis shows that the concentrations of Hg, As, Cd, Cr, Cu, Ni and Pb have exceeded the Malaysian Water Quality Standard. At 100% runoff, 92% and 74% of the zebrqfish embryo showed curve trunk and head malformation respectively, and yolk sac edema (19.8±6.1%) and pericardial edema (61.5±0.86%). This suggest that construction waste runoff was contaminated with heavy metals and teratogenic

    Highly Efficient Thermally Co-evaporated Perovskite Solar Cells and Mini-modules

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    The rapid improvement in the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has prompted interest in bringing the technology toward commercialization. Capitalizing on existing industrial processes facilitates the transition from laboratory to production lines. In this work, we prove the scalability of thermally co-evaporated MAPbI3 layers in PSCs and mini-modules. With a combined strategy of active layer engineering, interfacial optimization, surface treatments, and light management, we demonstrate PSCs (0.16 cm2 active area) and mini-modules (21 cm2 active area) achieving record PCEs of 20.28% and 18.13%, respectively. Un-encapsulated PSCs retained ∼90% of their initial PCE under continuous illumination at 1 sun, without sample cooling, for more than 100 h. Looking toward tandem and building integrated photovoltaic applications, we have demonstrated semi-transparent mini-modules and colored PSCs with consistent PCEs of ∼16% for a set of visible colors. Our work demonstrates the compatibility of perovskite technology with industrial processes and its potential for next-generation photovoltaics

    Comparative conventional extraction methods of ethanolic extracts of Clinacanthus nutans leaves on antioxidant activity and toxicity

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    Purpose: The purpose of this paper is to evaluate the antioxidant activity and toxicity of Clinacanthus nutans leaves from three conventional extraction methods, i.e. maceration, Soxhlet and magnetic stirring. Design/methodology/approach: Total flavonoid content (TFC) and phenolic content (TPC) were determined using colorimetric method of aluminum chloride and Folin-Ciocalteu (FC) assay, respectively. Antioxidant property of C. nutans was evaluated using 2,2'-diphenyl-1-pierylhydrazyl (DPPH) free radical scavenging assay. Cytotoxic activity of C. nutans against brine shrimp was evaluated based on LC50 (lethality concentration) after 24 h exposure to the plant extract. Findings: The highest TPC of C. nutans was observed with Soxhlet extraction method (98.87 ± 10.43 mg of gallic acid equivalents (GAE/g) followed by maceration (68.77 ± 2.45 mg of GAE/g) and magnetic stirring (46.75 ± 2.45 mg of GAE/g). Interestingly, remarkable highest TFC was observed with magnetic stirring (568.90 ± 4.85 mg of rutin equivalent (RE)/g) followed by maceration (249.60 ± 2.79 mg of RE/g) and Soxhlet (174.8 ± 1.74 mg of RE/g). On the other hands, the extract obtained using maceration method showed the highest antioxidant activity (IC50: 14.18 mg/mL compared to ascorbic acid 144.36 µg/mL). Cytotoxicity of C. nutans from all extraction methods showed similar LC50 values with maceration (3.81 mg/mL), Soxhlet (2.61 mg/mL) and magnetic stirring (4.56 mg/mL), respectively. Originality/value: Both phenolic and flavonoids are responsible for the antioxidant activity, of C. nutans extracts. Based on Meyer's toxicity index, all extracts were nontoxic (LC50>1 mg/mL)

    Surviving & Thriving; a healthy lifestyle app for new US firefighters: usability and pilot study protocol

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    In the United States (US), new firefighters’ fitness and health behaviors deteriorate rapidly after fire academy graduation. Over the long-term, this increases their risks for chronic diseases. This study protocol describes the proposed usability testing and pilot study of a newly designed and developed healthy lifestyle smartphone app, “Surviving & Thriving”, tailored towards young US firefighters. “Surviving & Thriving” will provide interactive educational content on four lifestyle factors; nutrition, sleep, physical activity, and resilience, and include a personalized journey, habit tracker, and elements of gamification to promote engagement and long-term healthy behavior change. The first phase of the app development entails alpha testing by the research team and pre-beta testing by a fire service expert panel which will help refine the app into a pre-consumer version. Upon completion of the full app prototype, beta ‘usability’ testing will be conducted among new fire academy graduates from two New England fire academies to collect qualitative and quantitative feedback via focus groups and satisfaction surveys, respectively. A last phase of piloting the app will evaluate the app’s efficacy at maintaining/improving healthy lifestyle behaviors, mental health metrics, and physical fitness metrics. We will also evaluate whether firefighters’ perceived “health cultures” scores (ratings of each fire station’s/fire department’s environments as to encouraging/discouraging healthy behaviors) modify the changes in health metrics after utilizing the app for three to six months. This novel user-friendly app seeks to help new firefighters maintain/improve their health and fitness more effectively, reducing their risk of lifestyle-related chronic disease. Firefighters who can establish healthy habits early in their careers are more likely to sustain them throughout their lives
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