Household, community, sub-national and country-level predictors of primary cooking fuel switching in nine countries from the PURE study

Introduction. Switchingfrom polluting (e.g. wood, crop waste, coal)to clean (e.g. gas, electricity) cooking fuels can reduce household air pollution exposures and climate-forcing emissions.While studies have evaluated specific interventions and assessed fuel-switching in repeated cross-sectional surveys, the role of different multilevel factors in household fuel switching, outside of interventions and across diverse community settings, is not well understood. Methods.We examined longitudinal survey data from 24 172 households in 177 rural communities across nine countries within the Prospective Urban and Rural Epidemiology study.We assessed household-level primary cooking fuel switching during a median of 10 years offollow up (∼2005–2015).We used hierarchical logistic regression models to examine the relative importance of household, community, sub-national and national-level factors contributing to primary fuel switching. Results. One-half of study households(12 369)reported changing their primary cookingfuels between baseline andfollow up surveys. Of these, 61% (7582) switchedfrom polluting (wood, dung, agricultural waste, charcoal, coal, kerosene)to clean (gas, electricity)fuels, 26% (3109)switched between different polluting fuels, 10% (1164)switched from clean to polluting fuels and 3% (522)switched between different clean fuels

Direct biosynthesis of ascorbic acid from glucose by Xanthomonas campestris through induced free-radicals

Ascorbic acid (20.4 g l(-1) in 50 h) was synthesized directly from glucose by Xanthomonas campestris as an adaptive response to induced free-radicals through HOCl treatment. Identity of ascorbic acid was confirmed through IR and NMR spectroscopy

Culture fluorescence dynamics in Xanthomonas campestris

Culture (NAD(P)H) fluorescence dynamics have been used to provide information on culture behaviour when Xanthomonas campestris was grown in a bioreactor. Culture fluorescence decreased by 1150 units in response to an increase in extracellular pH from 3.1 to 7.6. A mathematical model incorporating the effect of pH on the bulk NADH depletion reaction simulated the experimental data. The rates of bulk NADH formation and depletion reactions were 1 s(-1) and 719 (M h (1))(-1) s(-1), respectively. Subsequent to the initial NADH decrease, the culture fluorescence increased to within 200 units of its original value, with a concomitant decrease in oxygen uptake rate (OUR) from 7.3 to 3 mM h(-1). A mathematical model incorporating the hypothesis that the culture manipulated its OUR to increase its NADH level, simulated the experimental data. In addition, it was inferred from culture fluorescence that the intracellular oxygen availability becomes insufficient at or below 10% extracellular dissolved oxygen value. Studies on H2O2 addition to X. campestris to optimize the liquid-phase oxygen supply, showed no change in metabolic state, as indicated by NADH fluorescence, until 1.4 mmol H2O2 (g cell) (1) and a significant decrease above that. Investigations on the reasons for decreases in NADH fluorescence suggested a DNA-damaging Fenton reaction as the probable reason for the observed NADH decrease on addition of H2O2. (C) 2001 .

Oxidative-stress-induced production of pyocyanin by Xanthomonas campestris and its effect on the indicator target organism, Escherichia coli

Pyocyanin, a potential antimicrobial agent, was secreted by Xanthomonas campestris. Treatments with agents causing oxidative stress in the organism caused up to 4.4-fold increase in specific pyocyanin production. Pyocyanin added in the extracellular space did not affect growth rate of X. campestris, but decreased maximum cell concentration and specific product formation. However, the growth of Escherichia coil, the indicator target organism, was affected by pyocyanin. There was also a significant increase in the intracellular reactive oxygen species (ROS) concentration and antioxidant enzyme [catalase, superoxide dismutase (SOD)] concentrations, in the presence of pyocyanin. The intracellular ROS concentrations in E coli formed upon exposure to pyocyanin, which is an indicator of the toxicity, was dependent on the growth phase of the organism. Studies with mutants of E. coil showed that intracellular ROS concentration was not significantly affected by the absence of the regulon OxyR, but, was significantly higher in cases when the regulon rpoS or the genes-katG or katE were absent

Apoptosis extent increases in hybridoma cultures with temperature

Apoptosis plays an important role in determining efficacies of bioreactors employing hybridoma cells. Exposure to a 42 degrees C shock for 1 h increased the apoptosis extent (DNA fragmentation) by 32% in CCSC10 hybridoma. Further, glutamine at 2 mM decreased temperature-induced apoptosis by about 20%

Kinetics of anthocyanin extraction from fresh and dried grape waste

Anthocyanins are natural pigments which can be extracted from grape waste. Anthocyanin extraction from fresh and dry grape waste was studied using various solvents. Six solvents were employed, and methanol with 0.1% (v/v) HCl provided the highest extraction of 1.18 x 10(-3) g.g(-1) for dry waste. The same solvent also exhibited the fastest kinetics and the shortest time (7 hours) required to attain equilibrium. The kinetics of extraction were well-described by a two-interface mass transfer model which considered the solvent diffusion effects on the mass transfer coefficients. equilibrium and hold-up studies were also carried out using the safest solvent for human consumption from among the solvents used for extraction

Oxygen supply without gas-liquid film resistance to Xanthomonas campestris cultivation

Alternative methods of oxygen supply are of crucial importance, especially in viscous fermentations and shear-sensitive fermentations. A method of oxygen supply that completely eliminates the gas-liquid transport resistance has been presented. The method involves a need-based liquid-phase decomposition of hydrogen peroxide to provide the necessary oxygen. When Xanthomonas campestris was cultivated (viscous cultivation) using this method of oxygen supply, dissolved oxygen (DO) levels were maintained above the setpoint of 50% throughout the cultivation, whereas the conventional cultivation was able to meet culture oxygen demand only for about 6 h in a 72-h fermentation. Furthermore, the maximum specific growth rate and xanthan yields in the novel cultivation were 89% and 169%, respectively, of those obtained in conventional cultivation. A mathematical model was also developed to simulate and predict results in fermentations employing the presented methodology. In addition, studies with HOCl pretreatments indicated that monofunctional catalase may be responsible for the decomposition of H2O2 supplied externally to cells; HOCl pretreatments also increased the tolerance of cells to H2O2. The decomposition kinetics of externally supplied H2O2 was Michaelis-Menlen in nature with v(max) = 1.196 x 10(-6) M s(-1) and K-m = 0.21 mM. The catalase concentration was estimated to be 3.4 x 10(-10) mol/g of cells. (C) 1998 , Inc

Nickel biosorption from aqueous systems: Studies on single and multimetal equilibria, kinetics, and recovery

This paper reports studies on the removal of toxic trace metals (nickel separately, and simultaneously with cobalt) from aqueous solutions by employing fungal biosorbents, PFB1 and PFB2, which were developed in our laboratory. The observed maximum equilibrium uptake of nickel on the biosorbent was 214 mg.g(-1) (PFB1) and 110 mg.g(-1) (PFB2). The average efficiency for nickel removal was 84.5% (PFB1) and 60.8% (PFB2). The equilibrium uptake of nickel followed first-order Langmuir kinetics in the case of PFB1 and second-order Langmuir kinetics in the case of PFB2. Studies on simultaneous removal of cobalt and nickel indicated that the extent of secondary interactions between cobalt and nickel can be quantified by the change in Langmuir equilibrium constants for both metals. A mathematical model based on Fick's law of diffusion and Langmuir adsorption was developed to simulate the kinetics of nickel removal. The model was able to predict the experimentally observed kinetics well. From the simulations, the diffusivity of nickel in PFB1 was found to be 1.6 x 10(-8) m(2).s(-1). Desorption studies indicated that it was possible to reuse the biosorbent over three sorption-desorption cycles, and that acidic solutions desorbed better than basic or salt solutions. Among the desorbents studied, HCl and CaCl2, with dt sorption efficiencies equal to 73.2 and 74.1%, respectively, for PFB1 and 70.0 and 63.1%, respectively, for PFB2 at the end of three cycles, were found to be the best desorbents

Improvement in enzyme productivities from mold cultivations using the liquid-phase oxygen supply strategy

Cultivations of Aspergillus niger cells in which oxygen was provided through the liquid-phase oxygen supply strategy (which involves the need-based decomposition of H2O2 pulses to yield the necessary oxygen) were studied. Concentrations of H2O2 in the range of 1 to 5 mM were found to be suitable for use in cultivations. The growth rate constant of 0.17 h(-1) obtained in the H2O2-based cultivation, was comparable to that obtained in the cultivation with aeration; however, the maximum cell concentration in the H2O2-based cultivation was 124% of that obtained in cultivation with aeration. Maximum concentrations of catalase, protease and glucose oxidase obtained in the H2O2-based cultivation, were 240%, 172%, and 124% respectively, of those obtained in the cultivation with aeration. Further, the specific enzyme levels (units per gram cell) of catalase and protease obtained in the H2O2-based cultivation were 172% and 156% of those obtained in the cultivation with aeration, whereas, the specific glucose oxidase levels were comparable. In addition, the oxygen profiles inside the pellets of A. niger during both the modes of oxygen supply were described using mathematical models. Studies to elucidate the mechanism of oxygen availability showed that the decomposition of the H2O2 supplied in the extracellular space occurred intracellularly, as well as extracellularly, to yield oxygen. Also, the proton motive force (PMF) was found to be involved in the process of oxygen availability from H2O2 to A. niger cells