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1.
J Chem Educ ; 100(3): 1149-1154, 2023 Mar 14.
Article in English | MEDLINE | ID: mdl-37552785

ABSTRACT

The year 2020 will be remembered as the year of COVID-19 and its subsequent lockdowns. The time to return to face-to-face teaching has arrived, but the shadow of the disease still hangs over teachers, students, and society. Disruption in teaching can still occur for students, or even teachers, if they are either diagnosed as COVID-19 positive or as a contact case and forced to self-isolate. In order to limit the impact of self-isolation on learning, synchronous hybrid teaching (i.e., teaching face to face to students in a classroom and to students online at the same time) was successfully implemented owing to the combination of video conference software and a large interactive touchscreen. The setup presented in this paper allows courses to be broadcast to students at home (i.e., voice, visual pedagogic support, and, more interestingly, indications handwritten by the teacher) as well as simultaneously teaching to students in the classroom face-to-face. It also allows self-isolated teachers to teach tutorials from their home to students in the classroom. This paper focuses on the use of large interactive touchscreens for synchronous hybrid teaching and its evaluation by students using a questionnaire. The key findings of this study are that students prefer synchronous hybrid teaching rather than missing a course and that synchronous hybrid teaching should only be used in case of absolute necessity.

2.
Int J Biol Macromol ; 241: 124534, 2023 Jun 30.
Article in English | MEDLINE | ID: mdl-37121420

ABSTRACT

Herein, a cost-effective nanomaterial with excellent adsorption capacity, simply prepared, using manganese dioxide (MnO2) nanoparticles (NP) loaded on cellulose-based biochar of an agricultural waste, which is cassava peel carbon (CPC) and denoted as MnO2-NP-CPC. MnO2-NP-CPC is an environmental-friendly, and efficient adsorbent analyzed using different technics such as x-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and energy dispersive x-ray spectroscopy (EDX). MnO2-NP-CPC was used to remove three different toxic dyes; methylene blue (MB), malachite green (MG), and rhodamine b (RB) from a single (MB), (MG), (RB), binary (MB + MG), (MG + RB), (MB + RB) and ternary (MB + MG + RB) wastewater systems, the impact of pH, adsorbent dose (2-8), initial dye concentrations (10-30 mg/L), temperature (15-35 °C) were fully studied. Furthermore, all the sorption experiments were done including adsorption isotherms, kinetics, and thermodynamics to explore all the mechanisms involved in the sorption of the three ionic dyes in single, binary, and ternary systems. The equilibrium experiments data fitted well the monolayer Langmuir isotherm for the single dye system with correlation coefficients close to 1 (0.98 for MB, 0.99 for MG, and 0.86 for RB), while the extended Langmuir and extended Freundlich isotherms were investigated to study the interaction of the three dyes in their binary systems, the obtained results indicate clearly that the sorption fellows the extended Langmuir model. Besides, the kinetic study showed the applicability of the pseudo-second model for the three dyes. Finally, the thermodynamic adsorption was controlled by physisorption, endothermic, and spontaneous in nature.


Subject(s)
Manihot , Nanoparticles , Water Pollutants, Chemical , Wastewater , Coloring Agents/chemistry , Oxides , Manganese Compounds , Cellulose , Adsorption , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Cations , Kinetics , Hydrogen-Ion Concentration , Water Pollutants, Chemical/chemistry , Methylene Blue/chemistry
3.
Toxicol Rep ; 8: 386-394, 2021.
Article in English | MEDLINE | ID: mdl-33717991

ABSTRACT

The aim of this study was to assess the integrity and kidney overall functional capacity of subjects exposed to landfill emissions. Urine and blood levels of Pb and Cd, and several of the newly biomarkers of nephrotoxicity (Kim Injury Molecule 1 (KIM-1), alpha-1 Microglobulin (α1 M), beta-2 Microglobulin (ß2 M), Cystatin-C (Cyst C), Clusterin, alpha-glutathione S-transferase (GSTα), pi-glutathione S-transferase (GSTπ), Tissue Inhibitor of Metalloproteinase-1 (TIMP1), Calbindin, Neutrophil Gelatinase-Associated Lipocalin (NGAL), Osteopontin (OPN), (Retinol Binding Protein(RBP), Liver-type Fatty Acid-Binding Protein (FABP-1), Trefoil Factor 3 (TFF3), Collagen VI) were measured in order to assess glomerular and tubule damage in adults living near a landfill. Our results indicate glomerular dysfunction in exposed subjects, and supported evidence of necrosis of proximal and distal tubule epithelial cells as specific biomarkers began to appear in the urine. Positive correlation by Pearson test were obtained between : blood Pb and B-OPN, B-Cyst C, Calbindin, U-KIM-1, TIMP1, U-OPN, and U-Clusterin; and also, between urinary Cd and TIMP1, B-Clusterin, U-OPN, FABP-1, Albumin, and U-Clusterin. The relation between biomarkers of Cd/Pb exposure and early effect biomarkers in this study clearly predicts the future risk of severe kidney injury in subjects living close to the landfill.

4.
J Environ Sci (China) ; 44: 45-56, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27266301

ABSTRACT

Atmospheric aerosol samples (PM2.5-0.3, i.e., atmospheric particles ranging from 0.3 to 2.5µm) were collected during two periods: spring-summer 2008 and autumn-winter 2008-2009, using high volume samplers equipped with cascade impactors. Two sites located in the Northern France were compared in this study: a highly industrialised city (Dunkirk) and a rural site (Rubrouck). Physicochemical analysis of particulate matter (PM) was undertaken to propose parameters that could be used to distinguish the various sources and to exhibit seasonal variations but also to provide knowledge of chemical element composition for the interpretation of future toxicological studies. The study showed that PM2.5-0.3 concentration in the atmosphere of the rural area remains stable along the year and was significantly lower than in the urban or industrial ones, for which concentrations increase during winter. High concentrations of polycyclic aromatic hydrocarbons (PAHs), dioxins, furans and dioxin like polychlorinated biphenyls (DL-PCBs), generated by industrial activities, traffic and municipal wastes incineration were detected in the samples. Specific criteria like Carbon Preference Index (CPI) and Combustion PAHs/Total PAHs ratio (CPAHs/TPAHs) were used to identify the possible sources of atmospheric pollution. They revealed that paraffins are mainly emitted by biogenic sources in spring-summer whereas as in the case of PAHs, they have numerous anthropogenic emission sources in autumn-winter (mainly from traffic and domestic heating).


Subject(s)
Air Pollutants/analysis , Environmental Monitoring , Organic Chemicals/analysis , Particulate Matter/analysis , Aerosols/analysis , Atmosphere/chemistry , Cities , France , Incineration , Industry , Polychlorinated Biphenyls/analysis , Polycyclic Aromatic Hydrocarbons/analysis , Seasons
5.
Environ Pollut ; 206: 247-55, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26196314

ABSTRACT

The purpose of the study was to determine Pb and Cd concentrations in humans and to assess the effect of co-exposure to these metals on biomarkers of oxidative stress and nephrotoxicity. Blood and urine levels of Pb and Cd, oxidative stress and urinary renal biomarkers were measured in 77 subjects neighboring a discharge and 52 in the control site. Exposed subjects showed significantly higher levels of lead and cadmium in blood and urine than the controls. Excessive production of reactive oxygen species induced by these metals in exposed subjects conducted to a decrease in antioxidant defense system (GPx, Selenium, GSH) and an increase in lipid peroxidation (MDA). Moreover, changes in markers of nephrotoxicity (high urinary concentrations of total protein, RBP and CC16, as well as GSTα and LDH increased activities) suggested the occurrence of discrete and early signs of impaired renal function for the discharge neighboring population.


Subject(s)
Cadmium/toxicity , Environmental Exposure/adverse effects , Lead/toxicity , Adolescent , Adult , Aged , Antioxidants/metabolism , Biomarkers/metabolism , Cadmium/metabolism , Female , Humans , Kidney/drug effects , Kidney/physiology , Lead/metabolism , Lipid Peroxidation/drug effects , Male , Middle Aged , Oxidative Stress/drug effects , Reactive Oxygen Species/metabolism , Senegal , Waste Disposal Facilities , Young Adult
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