ABSTRACT
Historically, high levels of self-reported stress, anxiety, and depression are quite common among STEM students. Unfortunately, after multiple semesters of disrupted education due to COVID-19, these mental struggles among students, especially first-year (freshmen) undergraduate engineering students, have only been exacerbated. To mitigate these struggles, active and thoughtful engagement in learning can be implemented. The main goal of this study was to implement an engaging, teamwork building, service-focused Environmental Engineering activity in a freshmen Civil Engineering course (CE 101, Introduction to Civil Engineering) where students performed a water quality monitoring campaign using two commercially available lowcost test strips (2:1 and 5:1) while returning to campus. Additionally, the quality of the results obtained and the students' reception of this service-focused activity were evaluated. This activity (1) engaged the students, (2) had a positive impact on their environmental engineering knowledge, and (3) generated useful water quality data related to tap water and surficial water in northern Mississippi. Results highlighted the (1) overall good quality of the tap water collected, with the analyzed analytes significantly below the U.S. EPA maximum contaminant levels, (2) ability of low-cost test strips to generate trustworthy data (results obtained by the students were not statistically different, p > 0.05, compared to the quality assurance and quality control samples implemented) that can help local communities in assessing the quality of their water, and (3) ability to perform service-focused activity while teaching STEM courses. Students positively valued this service-focused activity, and they were enthusiastic about further experiencing this approach in other classes.
ABSTRACT
Historically, high levels of self-reported stress, anxiety, and depression are quite common among STEM students. Unfortunately, after multiple semesters of disrupted education due to COVID-19, these mental struggles among students, especially first-year (freshmen) undergraduate engineering students, have only been exacerbated. To mitigate these struggles, active and thoughtful engagement in learning can be implemented. The main goal of this study was to implement an engaging, teamwork building, service-focused Environmental Engineering activity in a freshmen Civil Engineering course (CE 101, Introduction to Civil Engineering) where students performed a water quality monitoring campaign using two commercially available low-cost test strips (2:1 and 5:1) while returning to campus. Additionally, the quality of the results obtained and the students' reception of this service-focused activity were evaluated. This activity (1) engaged the students, (2) had a positive impact on their environmental engineering knowledge, and (3) generated useful water quality data related to tap water and surficial water in northern Mississippi. Results highlighted the (1) overall good quality of the tap water collected, with the analyzed analytes significantly below the U.S. EPA maximum contaminant levels, (2) ability of low-cost test strips to generate trustworthy data (results obtained by the students were not statistically different, p > 0.05, compared to the quality assurance and quality control samples implemented) that can help local communities in assessing the quality of their water, and (3) ability to perform service-focused activity while teaching STEM courses. Students positively valued this service-focused activity, and they were enthusiastic about further experiencing this approach in other classes. © 2023 American Chemical Society and Division of Chemical Education, Inc.
ABSTRACT
Previous studies have determined biomass burning as a major source of air pollutants in the ambient air in Thailand. To analyse the impacts of meteorological parameters on the variation of carbonaceous aerosols and water-soluble ionic species (WSIS), numerous statistical models, including a source apportionment analysis with the assistance of principal component analysis (PCA), hierarchical cluster analysis (HCA), and artificial neural networks (ANNs), were employed in this study. A total of 191 sets of PM2.5 samples were collected from the three monitoring stations in Chiang-Mai, Bangkok, and Phuket from July 2020 to June 2021. Hotspot numbers and other meteorological parameters were obtained using NOAA-20 weather satellites coupled with the Global Land Data Assimilation System. Although PCA revealed that crop residue burning and wildfires are the two main sources of PM2.5, ANNs highlighted the importance of wet deposition as the main depletion mechanism of particulate WSIS and carbonaceous aerosols. Additionally, Mg2+ and Ca2+ were deeply connected with albedo, plausibly owing to their strong hygroscopicity as the CCNs responsible for cloud formation.
ABSTRACT
Magnesium, copper, zinc, iron and selenium complexes of ceftriaxone were prepared in a 1:1 ligand to metal ratio to investigate the ligational character of the antibiotic ceftriaxone drug (CFX). The complexes were found to have coordinated and hydrated water molecules, except for the Se (IV) complex, which had only hydrated water molecules. The modes of chelation were explained depending on IR, 1HNMR and UV–Vis spectroscopies. The electronic absorption spectra and the magnetic moment values indicated that Mg (II), Cu (II), Zn (II), Fe (III) and Se (VI) complexes form a six-coordinate shape with a distorted octahedral geometry. Ceftriaxone has four donation sites through nitrogen from NH2 amino, oxygen from triazine, β-lactam carbonyl and carboxylate with the molecular formulas [Mg(CFX)(H2O)2]·4H2O, [Cu(CFX)(H2O)2]·3H2O, [Fe(CFX)(H2O)(Cl)]·5H2O, [Zn(CFX)(H2O)2]·6H2O and [Se(CFX)(Cl)2]·4H2O and acts as a tetradentate ligand towards the five metal ions. The morphological surface and particle size of ceftriaxone metal complexes were determined using SEM, TEM and X-ray diffraction. The thermal behaviors of the complexes were studied by the TGA(DTG) technique. This study investigated the effect of CFX and CFX metal complexes on oxidative stress and severe tissue injury in the hepatic tissues of male rats. Fifty-six male rats were tested: the first group received normal saline (1 mg/kg), the second group received CFX orally at a dose of 180 mg/kg, and the other treated groups received other CFX metal complexes at the same dose as the CFX-treated group. For antibacterial activity, CFX/Zn complex was highly effective against Streptococcus pneumoniae, while CFX/Se was highly effective against Staphylococcus aureus and Escherichia coli. In conclusion, successive exposure to CFX elevated hepatic reactive oxygen species (ROS) levels and lipid peroxidation final marker (MDA) and decreased antioxidant enzyme levels. CFX metal complex administration prevented liver injury, mainly suppressing excessive ROS generation and enhancing antioxidant defense enzymes and in male rats.