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Polymers have been used in various industries over the past few decades due to their tremendous applications. Among these, polyhydroxyalkanoates and poly(lactic acid) are easily biodegradable biopolymers derived from bacteria, including recombinant Escherichia coli, Alcaligenes eutrophus, Alcaligenes latus, Azotobacter vinelandii, methylotrophs and Pseudomonas. Conventional petroleum‐derived polymers have become potentially harmful to the environment due to their complex degradation process. The nonbiodegradability of synthetic polymers has become a global issue of concern. There is an urgent need for a substitute to tackle the increasing environmental stress. Microorganisms are small factories for producing different types of polymers during their growth cycle. Various features like biodegradability, biocompatibility, nontoxicity and wide substrate spectrum make such microbial polymers highly reliable. Biopolymers such as alginate, cellulose, cyanophycin, levan, polyhydroxyalkanoates, xanthan, poly(lactic acid) and poly(γ‐glutamic acid) can be obtained from different microorganisms like Aureobasdium pullulans, Acetobacter xylinum, Bacillus thermoamylovorans and Cupriavidusnecator. These are extensively used in various fields like food, medicine, wastewater treatment, biofuel production, packaging and cosmetics. Despite being advantageous in several ways, the biopolymer market still faces several hurdles. This review mainly emphasizes the different types of biopolymers, production by microorganisms and various applications of these biopolymers in different fields. The main drawback limiting the development of these polymers is the high production cost and low efficiency of the microbial strains. Genetic recombination is an efficient technique to enhance the microbial yield and to expand the biopolymer market size. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The estimates of airborne fine particle (PM) concentrations are possible through rigorous empirical correlations based on the monitored PM data. However, such correlations change depending on the nature of sources in diverse ambient environments and, therefore, have to be environment specific. Studies presenting such correlations are limited but needed, especially for those areas, where PM is not routinely monitored. Moreover, there are a number of studies focusing on urban environments but very limited for coal mines and coastal areas. The aim of this study is to comprehensively analyze the concentrations of both PM and PM and develop empirical correlations between them. Data from 26 different sites spread over three distinct environments, which are a relatively clean coastal area, two coal mining areas, and a highly urbanized area in Delhi were used for the study. Distributions of PM in the 0.43-10-μm size range were measured using eight-stage cascade impactors. Regression analysis was used to estimate the percentage of PM in PM across distinct environments for source identification. Relatively low percentage of PM concentrations (21, 28, and 32%) in PM were found in clean coastal and two mining areas, respectively. Percentage of PM concentrations in PM in the highly urbanized area of Delhi was 51%, indicating a presence of a much higher percentage of fine particles due to vehicular combustion in Delhi. The findings of this work are important in estimating concentrations of much harmful fine particles from coarse particles across distinct environments. The results are also useful in source identification of particulates as differences in the percentage of PM concentrations in PM can be attributed to characteristics of sources in the diverse ambient environments. [ABSTRACT FROM AUTHOR]

Patients with functional bowel disorders frequently complain of bloating and abdominal pain, but no practical method is available to measure intestinal gas objectively. To evaluate a new technique, we evaluated 54 abdominal radiographs from 19 patients. A gastroenterologist and a radiologist independently outlined the intestinal gas bubbles in these films. Areas of gas bubbles were measured with a computer digitizing board. Bowel gas was also measured in 24 healthy controls, and in five emergency room patients, supine and erect radiographs were compared to evaluate the effects of position on bowel gas patterns. The two evaluators agreed well on the measured areas of bowel gas (r = 0.96), showing that this is a reliable method. Bowel gas was significantly greater in patients than in controls but did not correlate with symptoms. Bowel gas was significantly greater in supine than upright films, showing that the position of the patient must be standardized. [ABSTRACT FROM AUTHOR]

Abstract: The structural modification and properties of polymeric materials are of utmost importance in deciding their applications. In the present study, the synthesis of polyaniline (PANI) has been carried out via chemical oxidation in acidic medium by potassium-dichromate and the yield of synthesized polyaniline was found to be 75–80%. The copper per chlorate tetrabenzonitrile salt (CuClO4·4BN) used for chemical doping in synthesized polyaniline is stable in organic solvent like acetonitrile (AN) and benzonitrile (BN). The effect of Cu+1 oxidation state (dopant) in polyaniline has been characterized by FTIR. Electrical and dielectric measurements show the decrease in the intensity of the Cu+1 salt signal and the appearance of a radical signal due to the formation of oxidative coupled in polymeric species. Electrical and dielectric properties of doped polyaniline samples show significant changes due to the effect of dopant (CuClO4·4BN). It is observed that the conductivity is contributing both by formation of ionic complex and particularly dominated by electronic due to the mobility of charge carriers along the polyaniline chain. [Copyright &y& Elsevier]