Investigation of a Gas Hydrate Dissociation-Energy-Based Quick-Freezing Treatment for Sludge Cell Lysis and Dewatering

A gas Hydrate dissociation-energy-based Quick-Freezing treatment (HbQF) was applied for sewage sludge cell rupture and dewatering. Carbon dioxide (CO2) and water (H2O) molecules in sewage create CO2 gas hydrates, and subsequently the sludge rapidly freezes by releasing the applied pressure. Cell rupture was observed through a viability evaluation and leachate analysis. The decreased ratios of live cell to dead cells, increased osmotic pressure, and increased conductivity showed cell lysis and release of electrolytes via HbQF. The change in physicochemical properties of the samples resulting from HbQF was investigated via zeta potential measurement, rheological analysis, and particle size measurement. The HbQF treatment could not reduce the sludge water content when combined with membrane-based filtration post-treatment because of the pore blocking of fractured and lysed cells; however, it could achieve sludge microbial cell rupture, disinfection, and floc disintegration, causing enhanced reduction of water content and enhanced dewatering capability via a sedimentation post process. Furthermore, the organic-rich materials released by the cell rupture, investigated via the analysis of protein, polysaccharide, total organic carbon, and total nitrogen, may be returned to a biological treatment system or (an) aerobic digester to increase treatment efficiency

A study on mechanical properties of natural gas pipe material in high pressure hydrogen gas environment

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The voltage-gated potassium channel Shaker promotes sleep via thermosensitive GABA transmission

Genes and neural circuits coordinately regulate animal sleep. However, it remains elusive how these endogenous factors shape sleep upon environmental changes. Here, we demonstrate that Shaker (Sh)-expressing GABAergic neurons projecting onto dorsal fan-shaped body (dFSB) regulate temperature-adaptive sleep behaviors in Drosophila. Loss of Sh function suppressed sleep at low temperature whereas light and high temperature cooperatively gated Sh effects on sleep. Sh depletion in GABAergic neurons partially phenocopied Sh mutants. Furthermore, the ionotropic GABA receptor, Resistant to dieldrin (Rdl), in dFSB neurons acted downstream of Sh and antagonized its sleep-promoting effects. In fact, Rdl inhibited the intracellular cAMP signaling of constitutively active dopaminergic synapses onto dFSB at low temperature. High temperature silenced GABAergic synapses onto dFSB, thereby potentiating the wake-promoting dopamine transmission. We propose that temperature-dependent switching between these two synaptic transmission modalities may adaptively tune the neural property of dFSB neurons to temperature shifts and reorganize sleep architecture for animal fitness. Ji-hyung Kim and Yoonhee Ki et al. show that low temperatures suppress sleep in Drosophila by increasing GABA transmission in Shaker-expressing GABAergic neurons projecting onto the dorsal fan-shaped body, while high temperatures potentiate dopamine-induced arousal by reducing GABA transmission. This study highlights a role for Shaker in sleep modulation via a temperature-dependent switch in GABA signaling

Improved reversibility in lithium-oxygen battery: Understanding elementary reactions and surface charge engineering of metal alloy catalyst

Most Li-O-2 batteries suffer from sluggish kinetics during oxygen evolution reactions (OERs). To overcome this drawback, we take the lesson from other catalysis researches that showed improved catalytic activities by employing metal alloy catalysts. Such research effort has led us to find Pt3Co nanoparticles as an effective OER catalyst in Li-O-2 batteries. The superior catalytic activity was reflected in the substantially decreased overpotentials and improved cycling/rate performance compared to those of other catalysts. Density functional theory calculations suggested that the low OER overpotentials are associated with the reduced adsorption strength of LiO2 on the outermost Pt catalytic sites. Also, the alloy catalyst generates amorphous Li2O2 conformally coated around the catalyst and thus facilitates easier decomposition and higher reversibility. This investigation conveys an important message that understanding elementary reactions and surface charge engineering of air-catalysts are one of the most effective approaches in resolving the chronic sluggish charging kinetics in Li-O-2 batteries.

Antiobesity and lipid-lowering effects of Bifidobacterium spp. in high fat diet-induced obese rats

<p>Abstract</p> <p>Background</p> <p>Recent studies have reported the preventive effects of probiotics on obesity. Among commensal bacteria, bifidobacteria is one of the most numerous probiotics in the mammalian gut and are a type of lactic acid bacteria. The aim of this study was to assess the antiobesity and lipid-lowering effects of <it>Bifidobacterium </it>spp. isolated from healthy Korean on high fat diet-induced obese rats.</p> <p>Methods</p> <p>Thirty-six male Sprague-Dawley rats were divided into three groups as follows: (1) SD group, fed standard diet; (2) HFD group, fed high fat diet; and (3) HFD-LAB group, fed high fat diet supplemented with LAB supplement (<it>B. pseudocatenulatum </it>SPM 1204, <it>B. longum </it>SPM 1205, and <it>B. longum </it>SPM 1207; 10⁸~ 10⁹CFU). After 7 weeks, the body, organ, and fat weights, food intake, blood serum levels, fecal LAB counts, and harmful enzyme activities were measured.</p> <p>Results</p> <p>Administration of LAB reduced body and fat weights, blood serum levels (TC, HDL-C, LDL-C, triglyceride, glucose, leptin, AST, ALT, and lipase levels), and harmful enzyme activities (β-glucosidase, β-glucuronidase, and tryptophanase), and significantly increased fecal LAB counts.</p> <p>Conclusion</p> <p>These data suggest that <it>Bifidobacterium </it>spp. used in this study may have beneficial antiobesity effects.</p