Effect of carrier gas on the gas sensing performance of Co12xNixMnxFe2yCeyO4 double-substitution spinel in flammable gases and volatile organic compounds

The presence of high concentrations of flammable gases and volatile organic compounds in the atmosphere has been widely reported to be detrimental to human survival. A lot of research effort has been put toward finding an efficient means of quick detection of these gases below their ‘immediately dangerous to life or health’ concentrations. Detecting these gases in an oxygendeficient environment is a crucial task to consider and has been overlooked. In this research, doublesubstitution spinel with the chemical formula Co12xNixMnxFe2yCeyO4, where 0 x = y 0.3, was prepared via the glycol-thermal technique. The final products, following appropriate substitution, were CoFe2O4 (dried naturally), CoFe2O4 (dried with infrared lamp), Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4, Co0.6Ni0.2Mn0.2Fe1.8Ce0.2O4 and Co0.4Ni0.3Mn0.3Fe1.7Ce0.3O4 spinel ferrites. The X-ray diffractometry (XRD), high-resolution transmission electron micrographs (HRTEM) and X-ray photoelectron spectroscopy (XPS) of the samples confirmed the formation of the spinel. The gas sensing performance of these samples was tested at the operating temperature of 225 C toward liquefied petroleum gas (LPG), ammonia, ethanol and propanol. The Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4-based sensor was selective to LPG, with a high response of 116.43 toward 6000 ppm of LPG when helium was used as the carrier gas, 3.35 when dry air was the carrier gas, 4.4 when nitrogen was the carrier gas, but it was not sensitive when argon was used as the carrier gas.https://www.mdpi.com/journal/coatingsam2024PhysicsNon

Tungsten oxide thin film for room temperature nitrogen dioxide gas sensing

Tungsten oxide (WO3) thin films for gas sensing have been successfully deposited using reactive direct current (DC) magnetron sputtering at different deposition temperatures (300 °C, 400 °C and 500 °C). The structural, morphological properties, thickness and composition have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS) techniques. To investigate the effect of deposition temperature on the gas sensing properties of deposited thin films on alumina substrates, was conducted using the Kenosistec gas sensing unit. WO3 thin film deposited at 500 °C exhibited a higher response when sensing Nitrogen dioxide (NO2) at room temperature as compared to the thin films prepared at 300 °C and 400 °C, respectively. However, as deposited WO3 thin films exhibited low sensitivity when sensing reducing gases such as hydrogen (H2) and ammonia (NH3), which was an indication of good selectivity properties of WO3 related sensors

Impact of Dolutegravir-Based Antiretroviral Therapy on Piperaquine Exposure following Dihydroartemisinin-Piperaquine Intermittent Preventive Treatment of Malaria in Pregnant Women Living with HIV.

Dihydroartemisinin-piperaquine, an artemisinin-based combination therapy, has been identified as a promising agent for intermittent preventive treatment of malaria in pregnancy. However, in pregnant women living with HIV (PLWH), efavirenz-based antiretroviral therapy (ART) significantly reduces the plasma exposure of piperaquine. In an open-label, nonrandomized, fixed-sequence, pharmacokinetic study, we compared piperaquine plasma concentrations in 13 pregnant women during a 3-day treatment course of dihydroartemisinin-piperaquine when coadministered with efavirenz-based versus dolutegravir-based ART in the second or third trimester of pregnancy. Piperaquine concentrations were measured over a 28-day period, while on efavirenz-based ART and after switching to dolutegravir-based ART. Noncompartmental analysis was performed, and geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were generated to compare piperaquine pharmacokinetic parameters between these two treatment periods. Compared with efavirenz-based ART, coadministration of dihydroartemisinin-piperaquine and dolutegravir-based ART resulted in a 57% higher overall piperaquine exposure (area under the concentration-time curve from 0 to 672 h [AUC ]) (GMR, 1.57; 90% CI, 1.28 to 1.93). Piperaquine's day 7 concentrations were also 63% higher (GMR, 1.63; 90% CI, 1.29 to 2.11), while day 28 concentrations were nearly three times higher (GMR, 2.96; 90% CI, 2.25 to 4.07). However, the maximum piperaquine concentration ( ) remained similar (GMR, 1.09; 90% CI, 0.79 to 1.49). Dihydroartemisinin-piperaquine was well tolerated, with no medication-related serious adverse events observed in this small study. Compared with efavirenz-based ART, a known inducer of piperaquine metabolism, dolutegravir-based ART resulted in increased overall piperaquine exposure with pharmacokinetic parameter values that were similar to those published previously for pregnant and nonpregnant women. Our findings suggest that the efficacy of dihydroartemisinin-piperaquine will be retained in pregnant women on dolutegravir

Impact of Dolutegravir-Based Antiretroviral Therapy on Piperaquine Exposure following Dihydroartemisinin-Piperaquine Intermittent Preventive Treatment of Malaria in Pregnant Women Living with HIV

Dihydroartemisinin-piperaquine, an artemisinin-based combination therapy, has been identified as a promising agent for intermittent preventive treatment of malaria in pregnancy. However, in pregnant women living with HIV (PLWH), efavirenz-based antiretroviral therapy (ART) significantly reduces the plasma exposure of piperaquine. In an open-label, nonrandomized, fixed-sequence, pharmacokinetic study, we compared piperaquine plasma concentrations in 13 pregnant women during a 3-day treatment course of dihydroartemisinin-piperaquine when coadministered with efavirenz-based versus dolutegravir-based ART in the second or third trimester of pregnancy. Piperaquine concentrations were measured over a 28-day period, while on efavirenz-based ART and after switching to dolutegravir-based ART. Noncompartmental analysis was performed, and geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were generated to compare piperaquine pharmacokinetic parameters between these two treatment periods. Compared with efavirenz-based ART, coadministration of dihydroartemisinin-piperaquine and dolutegravir-based ART resulted in a 57% higher overall piperaquine exposure (area under the concentration-time curve from 0 to 672 h [AUC0-672 h]) (GMR, 1.57; 90% CI, 1.28 to 1.93). Piperaquine's day 7 concentrations were also 63% higher (GMR, 1.63; 90% CI, 1.29 to 2.11), while day 28 concentrations were nearly three times higher (GMR, 2.96; 90% CI, 2.25 to 4.07). However, the maximum piperaquine concentration (Cmax) remained similar (GMR, 1.09; 90% CI, 0.79 to 1.49). Dihydroartemisinin-piperaquine was well tolerated, with no medication-related serious adverse events observed in this small study. Compared with efavirenz-based ART, a known inducer of piperaquine metabolism, dolutegravir-based ART resulted in increased overall piperaquine exposure with pharmacokinetic parameter values that were similar to those published previously for pregnant and nonpregnant women. Our findings suggest that the efficacy of dihydroartemisinin-piperaquine will be retained in pregnant women on dolutegravir. (The study was registered on PACTR.samrc.ac.za [PACTR201910580840196].). Erratum: In Fig.2 and Fig. S1, the first value on the y axis should read as “1” instead of “0.

Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends

This paper presents a detailed study on the role of various annealing treatments on organic poly(3-hexylthiophene) and [6]-phenyl-C61-butyric acid methyl ester blends under different experimental conditions. A combination of analytical tools is used to study the alteration of the phase separation, structure and photovoltaic properties of the P3HT:PCBM blend during the annealing process. Results showed that the thermal annealing yields PCBM ‘‘needle-like’’ crystals and that prolonged heat treatment leads to extensive phase separation, as demonstrated by the growth in the size and quantity of PCBM crystals. The substrate annealing method demonstrated an optimal morphology by eradicating and suppressing the formation of fullerene clusters across the film, resulting in longer P3HT fibrils with smaller diameter. Improved optical constants, PL quenching and a decrease in the P3HT optical bad-gap were demonstrated for the substrate annealed films due to the limited diffusion of the PCBM molecules. An effective strategy for determining an optimized morphology through substrate annealing treatment is therefore revealed for improved device efficiency.Web of Scienc

The effect of acids precipitants on the synthesis of WO3 hierarchical nanostructures for highly selective and sensitive H2S detection

The detection and monitoring of H2S gas at high and lower concentrations is very crucial since this gas is highly toxic and can affect tissues and organs, especially in occupational environment. This work reports on the synthesis of WO3 nanostructures-based sensors for highly sensitive and selective H2S detection at low operating temperatures. These WO3 nanostructures were synthesized using pressurized hydrothermal process. Different acids from weak to strong (HNO3, H2SO4, and HCl) were employed as precipitants to form supposedly hierarchical and cube-like nanostructures of WO3. These WO3 nanostructures were characterized by XRD, SEM, TEM, XPS and BET analysis. The fabricated WO3 sensors were exposed to different target gases (CO2, H2, CH4, NH3, LPG and H2S) at different concentrations. They were found to be selective to H2S, and the WO3 precipitated by HCl otherwise referred to as WO3-HCl was found to be highly sensitive, with high response of S = 1394.04 towards 150 ppm of H2S at 125°C operating temperature. The WO3 precipitated by H2SO4 named WO3-H2SO4 showed a high response of 141.64 at 125°C operating temperature. Lastly, WO3 precipitated by HNO3 called WO3-HNO3, recorded a H2S response of 125.75 also at 125°C operating temperature. The HCl-precipitated WO3 is a promising candidate for selective detection of H2S, being the most sensitive in the series

Tungsten oxide thin film for room temperature nitrogen dioxide gas sensing

Tungsten oxide (WO3) thin films for gas sensing have been successfully deposited using reactive direct current (DC) magnetron sputtering at different deposition temperatures (300 °C, 400 °C and 500 °C). The structural, morphological properties, thickness and composition have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS) techniques. To investigate the effect of deposition temperature on the gas sensing properties of deposited thin films on alumina substrates, was conducted using the Kenosistec gas sensing unit. WO3 thin film deposited at 500 °C exhibited a higher response when sensing Nitrogen dioxide (NO2) at room temperature as compared to the thin films prepared at 300 °C and 400 °C, respectively. However, as deposited WO3 thin films exhibited low sensitivity when sensing reducing gases such as hydrogen (H2) and ammonia (NH3), which was an indication of good selectivity properties of WO3 related sensors

Effect of dihydroartemisinin/piperaquine for malaria intermittent preventive treatment on dolutegravir exposure in pregnant women living with HIV.

BACKGROUND: In sub-Saharan Africa, the burdens of malaria and HIV infections overlap. In settings with moderate-to-high malaria transmission intensity, pregnant women living with HIV (PLWH) require both ART and malaria intermittent preventive treatment (IPTp). Dihydroartemisinin/piperaquine has been identified as a promising alternative to sulfadoxine/pyrimethamine for IPTp. However, another antimalarial drug, artesunate/amodiaquine, similar to dihydroartemisinin/piperaquine, was previously shown to reduce dolutegravir exposure in non-pregnant adults. OBJECTIVES: To investigate the effect of dihydroartemisinin/piperaquine on dolutegravir plasma exposure in pregnant women on dolutegravir-based ART. METHODS: We conducted an open-label, non-randomized, fixed-sequence, pharmacokinetic study in PLWH in Malawi. Dolutegravir concentrations were measured over a 24 h period, before and after the recommended 3 day treatment dose of dihydroartemisinin/piperaquine in 12 pregnant women in their second or third trimester. Non-compartmental analysis was performed, and geometric mean ratios (GMRs) and 90% CIs were generated to compare dolutegravir pharmacokinetic parameters between the two treatment periods. RESULTS: Co-administration of dihydroartemisinin/piperaquine and dolutegravir increased dolutegravir's overall exposure (AUC0-24) and Cmax by 30% (GMR 1.30; 90% CI 1.11-1.52) and 31% (GMR 1.31; 90% CI 1.13-1.51), respectively. The dolutegravir trough (C24) concentration increased by 42% (GMR 1.42; 90% CI 1.09-1.85). The combined treatments were well tolerated with no serious adverse events observed. CONCLUSIONS: Dihydroartemisinin/piperaquine may be administered with dolutegravir-based ART in pregnant women as the modest increase in dolutegravir exposure, similar to pharmacokinetic parameter values published previously, ensures its efficacy without any clinically significant adverse events observed in this small study

Life cycle assessment of facile microwave-assisted zinc oxide (ZnO) nanostructures

Summarization: The life cycle assessment of several zinc oxide (ZnO) nanostructures, fabricated by a facile microwave technique, is presented. Key synthesis parameters such as annealing temperature, varied from 90 °C to 220 °C, and microwave power, varied from 110 W to 710 W, are assessed. The effect of these parameters on both the structural characteristics and the environmental sustainability of the nanostructures is examined. The nanostructures were characterized by means of X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), ultraviolet–visible spectroscopy (UV–Vis), Photoluminescence (PL) and Brunauer–Emmett–Teller (BET) analysis. Crystalline size was found to be 22.40 nm at 110 W microwave power, 24.83 nm at 310 W, and 24.01 nm at 710 W. Microwave power and synthesis temperature were both directly proportional to the surface area. At 110 W the surface area was 10.44 m2/g, at 310 W 12.88 m2/g, and at 710 W 14.60 m2/g; while it was found to be 11.64 m2/g at 150 °C and 18.09 m2/g at 220 °C. Based on these, a life cycle analysis (LCA) of the produced ZnO nanoparticles was carried out, using the ZnO surface area (1 m2/g) as the functional unit. It was found that the main environmental weaknesses identified during the production process were; (a) the use of ethanol for purifying the produced nanomaterials and (b) the electricity consumption for the ZnO calcination, provided by South Africa's fossil-fuel dependent electricity source. When the effect of the key synthesis parameters on environmental sustainability was examined it was found that an increase of either microwave power (from 110 to 710 W) or synthesis temperatures (from 90 to 220 °C), results in higher sustainability, with the environmental footprint reduced by 27% and 41%, respectively. Through a sensitivity analysis, it was observed that an electricity mix based on renewable energy could improve the environmental sustainability of the nanoparticles by 25%.Παρουσιάστηκε στο: Science of the Total Environmen