Journal de chimie analytique environnementale

Major challenges still exist in the cost-competitive production of cellulosic ethanol. Lignocellulose deconstruction using physiochemical pretreatments continues to be the most efficient way to remove lignin and expose cellulose for enzyme-mediated sugar reduction. Recent interest in the development of “value-added” lignin co-products and the desire to reduce the use of hazardous materials has prompted a resurgence of interest in alternative lignocellulosic feedstock and research into environment-friendly biological pretreatments. This article provides an overview of bioethanol processes and economics, standard and alternative feedstocks, physiochemical and biological pretreatments, and lignin chemistry. The chemistry and mode of action of ligninolytic and cellulolytic enzymes naturally expressed by white-rot and brown-rot fungi are described. This comprehensive review offers a renewed perspective on alternative high-lignin content cellulosic feedstock - specifically, bamboo - and the potential for microbial-based pretreatments that release cellulose for enzymatic breakdown and the subsequent fermentation of reduced sugars, while leaving lignin structures intact for conversion to valuable co-products.

Methyl-2-naphthyl ether (MNE) is an organic compound and used as the primary moiety for the synthesis of several antimicrobial and anti-inflammatory agents. This study was attempted to evaluate the impact of biofield energy treatment on the physical, thermal, and spectroscopic properties of MNE. The study was carried out in two groups i.e., control and treated. The treated group was subjected to Mr. Trivedi’s biofield treatment. Afterward, the control and treated samples of MNE were evaluated using X-ray diffraction (XRD), surface area analyzer, differential scanning calorimetry (DSC), thermogravimetric analysis-derivative thermogravimetric analysis (TGA-DTG), Fourier transform infrared (FTIR), and ultraviolet-visible (UV-Vis) spectroscopy. The XRD study exhibited the decrease in average crystallite size by 30.70%. The surface area analysis showed 5.32% decrease in surface area of the treated sample with respect to the control. The DSC thermogram of treated MNE exhibited no significant change in the melting temperature; however, the latent heat of fusion was slightly increased (0.83%) after biofield treatment as compared to the control sample. The TGA analysis showed the onset temperature of thermal degradation at 158℃ in the control sample that was reduced to 124℃ after biofield treatment. The result showed about 21.52% decrease in onset temperature of thermal degradation of treated MNE as compared to the control. Similarly, the end-set temperature of thermal degradation was also reduced by 13.51% after biofield treatment with respect to the control. The FT-IR and UV spectroscopic studies did not show any changes in the wavenumber and wavelength, respectively in treated MNE with respect to the control. Overall, the XRD, surface area and thermal analysis suggest that biofield treatment has the impact on physical and thermal properties of the treated MNE as compared to the control.

Present work deals with the extended applicability of the in situ generated supported silicomolybdic heteropolyanions from the sol-gel synthesized MoO3/SiO2 catalyst for the acetylation of glycerol. The best results were obtained at 118°C using a glycerol: AcOH molar ratio of 1:10 with 100% glycerol conversion in 2 hr and 76% selectivity for triacetin when the reaction was continued for 20 hr.

Association of particulate matter with endothelial function Current evidence has confirmed the definite correlation between air pollution and cardiovascular disease. One of the mechanisms was the adverse effect on endothelial function. However, there is heterogeneity between the air pollution and endothelial function in different studies. We performed a meta-analysis to determine the direction and strength of the association. PubMed, EMBASE, Cochrane library and Web of Science were searched for a combination of keywords related to major air pollutants and to the indexes of endothelial function, including reactive hyperemia, flow-mediated dilation and nitroglycerin-mediated dilatation. Thirteen of reviewed articles with sufficient details met inclusion criteria. Descriptive and quantitative information was extracted from the included studies. A pooled estimate in a random effects model was computed, and change in endothelial function (95% CIs) were calculated for each increment of 10 μg/m3 in PM2.5, and 1 μg/ m3 scaled for black carbon. A 0.27% decrease in flow-mediated dilation was marginally associated with per 1 μg/m3 increase in PM2.5 in overall risk estimate analysis, with the greatest effect occurred in PM2.5 exposure for 1-day lag. Subgroup analyses have shown that the effect was modified by the factors as follows: American, subjects aged less than 55 years old, the proportion of female less than 50%, and the panel design. A 0.07 mm decrease in brachial artery diameter and 2.46% decrease in nitroglycerin-mediated dilation for per 1 μg/m3 increment in BC were observed in the pooled analysis from two studies(P=0.005 and P=0.043, respectively). No significant association was found between black carbon and flow-mediated dilation. Short-term exposure to PM2.5 and black carbon was associated with endothelial function, which provided the evidence for the increased risk of cardiovascular disease due to air pollution

The bark of Dacryodes edulis (G. Don) H.J Lam have been used over the years in rural communities across the tropical region for its medicinal potentials. Phytochemicals are bioactive constituents which are produced via secondary metabolism in relatively small amounts. To ascertain the phytochemical components responsible for the ethno-medicinal properties, a qualitative and quantitative screening of the bark of the tree was conducted. The phytochemical screening of the bark of Dacryodes edulis was sourced from benin city , south-south Nigeria revealed that alkaloids(18.13 mg/kg), Phenolic compounds (22.01 mg/kg), Flavenoids (60.91 mg/kg), Tannins (18.16 mg/kg), Saponins (3.16 mg/kg), Anthraquinones (12.16 mg/kg), Cardiac glycosides (0.81 mg/kg) and steroids (0.91 mg/kg) were significantly present in the sample. The presence of these phytochemicals gives credence to the medicinal benefits that the bark of this plant has been used for in the past years.

Spring water is a major source of water for drinking, agricultural, and industrial desires. The availability of water determines the location and activities of humans in an area and our growing population is placing great demands upon natural fresh water resources. However, they are sometimes exposed to various forms of pollution such as agricultural, industrial and residential. In the present study spring water samples were collected from Arbaminch spring and have been analyzed for physico-chemical parameters pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), total alkalinity, total hardness (TH), Cl-, F-, NO3 -, NO2 -, Na+, K+, Ca2+, SO4 2- and Mg2+. The obtained values of each parameter were compared with the standard values set by the World Health Organization (WHO), standards organization of Nigeria (SON), Indian standards institution (ISI) and United nations environmental protection agency (USEPA) drinking water quality standards. The values of each parameter were found to be within the safe limit values except Cl- , total alkalinity and F-. But the concentration of Cl- was found higher than the permissible levels of Cl- for safe drinking water set by WHO and SON. Total alkalinity have been found to be high as compared to desired limit value, but little higher compared to maximum permissible limit values of ISI. The average value of F- was also found above the maximum standard values of WHO and SON, but within the maximum standard values of US-EPA

A number of tobacco manufacturers are promoting products where the tobacco is reportedly “heated” rather than burned. It has been claimed that certain heated tobacco products produce only mainstream and no side-stream emissions. In this study we investigated these claims for a commercially available heated tobacco product and, by using a simple experimental design, investigated whether the high temperature heating of the tobacco matrix during product activation and use results in the generation of side-stream emissions. By way of comparison, the Nicorette® inhalator and a leading e-cigarette brand were also investigated. Our findings indicated that a large number of different chemical compounds were released into the airspace around the heated tobacco product when switched on and during consumer use indicating the generation of side-stream emissions. As the public health community has concluded there is no safe level of exposure to tobacco-containing product emissions, this would be of concern and warrants further investigation. Based on our data showing side-stream emissions from the tobacco matrix, the use of heated tobacco products in indoor public places should fall under the same regulations as cigarettes.

An experimental method is presented for the first time to determine the concentration of nicotine in exhaled breath following e-cigarette use in experienced participants and the impact that vaping topography has on the retention rate of nicotine. Aerosols from e-cigarettes containing different concentrations of nicotine were first evaluated by GC-FID to determine the concentration of nicotine delivered per puff versus machine - vaping intensity. These e-cigarettes were then vaped by participants through a cigarette holder attached to a smoking topography analyzer which recorded puff volume and puff duration. This allowed the concentration of nicotine in the aerosol inhaled by the participant during each puff to be determined. A PTR-MS instrument was then used to determine the concentration of nicotine exhaled following each use of the e-cigarette. By dividing this figure by the nicotine concentration delivered enabled its retention rate to be calculated. The principal finding was over 99% of the nicotine was retained by the participants when the e-cigarette aerosol was inhaled and a reduced but still substantial quantity was retained (on average 86%) when the e-cigarette aerosol was held in the mouth only (i.e, no inhalation). In both cases, the nicotine concentrations detected in the exhaled breath were low (range 1.8 - 1786 ppb). The experimental method presented here may be used to determine the concentration of other e-cigarette aerosol constituents in exhaled breath and the retention rate of those constituents which is useful for the evaluation of e-cigarettes from a consumer and bystander perspective.