Fabrication and Characterization of Metal-Loaded Mixed Metal Oxides Gas Sensors for the Detection of Hazardous Gases

This study concerns gas sensors that may protect individuals by detecting hazardous gases that may be generated in hot spaces (≥50°C) with residues of organic waste. We investigated the responses and selectivities of the sensors to different kinds of hazardous gases such as acetaldehyde, toluene and hydrogen sulfide. We also investigated operating temperatures and catalysts for the sensors. The thick film semiconductor sensors that detected some hazardous gases were prepared using nano-sized sensing material powders (SnO2, WO3, ZnO) that were prepared through sol-gel and precipitation methods. The nano-sized sensing materials were blended with various amounts of metal oxides (SnO2, ZnO, WO3) and coated with transition metals (Pt, Pd, Ru, Au, Ag, Cu and In). The metal oxide thick films were fabricated on an Al2O3 plate with a Ni-Cr heater and a Pt electrode through a screen-printing method. Morphologies, compositions, phases, surface areas and particle sizes of sensor compounds were examined by SEM, EDS, XRD and BET analysis. The investigated response to the various hazardous vapors was expressed as the value of Ra/Rg, where Ra and Rg are the resistance of the sensor material in the air and in hazardous gas, respectively

Engineering of Klebsiella oxytoca capable of simultaneous utilization of multiple sugars for the production of 2, 3- Butanediol

From various biomasses such as lignocellulose and microalgae, many kinds of monosaccharides including glucose, galactose, xylose, mannose, ribose, rhamnose, and fucose can be obtained. Among them, galactose and xylose are the major carbon sources except for glucose in nature, and both sugars can serve as additive for the production of desired chemicals in the glucose-based fermentation. However, in many microorganisms, the glucose hampers utilization of galactose and xylose until depletion of glucose owing to Carbon Catabolite Repression (CCR) mechanism, which has been a big hurdle for the development of bioprocess utilizing multiple carbon sugars. Here, we developed Klebsiella oxytoca capable of simultaneous utilization of three sugars including glucose, galactose and xylose for the fermentative production of 2,3-butanediol which is a vital platform compound, used as liquid fuel and chemical raw material. To eliminate CCR and utilize multiple sugars, the phosphotransferase system (PTS) which is the main transporter for glucose was disrupted, in which cells could uptake glucose through alternative pathway and the transport system for other sugars could be activated. To verify the removal of CCR by disruption of PTS, the engineered strain was cultivated with two or three sugars and, we found that the simultaneous consumption of galactose and xylose was achieved although glucose consumption rate was decreased a little. At the time point of complete consumption of glucose, most galactose was also consumed and, about 30 % of xylose was consumed before glucose depletion. Under the simultaneous utilization of galactose and xylose along with glucose, 2,3-butaneidol was also successfully produced as high as 0.3 g/g, which yield is similar as that in cultivation with glucose as a sole carbon source. To the best of our knowledge, this is the first example of CCR elimination in K. oxytoca and, we think that our strategy sheds new light on an engineering of K. oxytoca for commercial exploitation of biomass to produce value-added products

Down-regulation of ARC contributes to vulnerability of hippocampal neurons to ischemia/hypoxia

AbstractARC is a caspase recruitment domain-containing molecule that plays an important role in the regulation of apoptosis. We examined ARC expression during neuronal cell death following ischemic injury in vivo and in vitro. After exposure to transient global ischemic conditions, the expression of ARC was substantially reduced in the CA1 region of hippocampus in a time-dependent manner with concomitant increase of TUNEL-positive cells. Quantitative analysis using Western blotting exhibited that most of ARC protein disappeared in the cultured hippocampal neurons exposed to hypoxia for 12 h and showing 60% cell viability. Forced expression of ARC in the primary cultures of hippocampal neurons or B103 neuronal cells significantly reduced hypoxia-induced cell death. Further, the C-terminal P/E rich region of ARC was effective to attenuate hypoxic insults. These results suggest that down-regulation of ARC expression in hippocampal neurons may contribute to neuronal death induced by ischemia/hypoxia

BIOMECHANICAL ANALYSIS OF BACK-SOMERSAULT KICKS IN TAEKWONDO

This study was purposed to investigate biomechanical differences between best and worst trials in performing back-somersault kicks in Taekwondo. Six elite members of college Taekwondo demonstration team participated in this study and executed each ten trials of single back-somersault kick and double back-somersault kick, respectively. High speed motion capturing system collected positions of 21 markers on major anatomical locations to obtain motion data of full body segments. After post-processing procedure, results showed that the best trial of back-somersault kicks indicated longer preparation time (countermovement), larger range of motions of hip joint, and higher peak angular velocities of knee and hip joints prior to take-off than those of the worst trial. We concluded that athletes should avoid a quick countermovement before take-off, which induces insufficient strain energy of lower extremities and ground reaction impulse. Therefore, a sufficient time for muscle contractions are required to develop high power

Fabrication of layer-by-layer photonic crystals using two polymer microtransfer molding

A method of manufacturing photonic band gap structures operable in the optical spectrum has been presented. The method comprises the steps of filling a plurality of grooves of an elastomeric mold with a UV curable first polymer, each groove in parallel with each other and partially curing the first polymer. A second polymer is coated on the first polymer. A substrate or a multi-layer polymer structure is placed on the filled mold and the resulting structure is exposed to UV light (i.e., is UV cured). The mold is peeled away from the first and second polymers such that a layer of polymer rods is formed on the substrate/multi-layer polymer structure. The process is repeated until a desired number of layers have been formed. The multi-layer structure can be used to create ceramic and metallic photonic band gaps by infiltration, electro-deposition, and/or metal coating

Role of S5b/PSMD5 in Proteasome Inhibition Caused by TNF-α/NFκB in Higher Eukaryotes

SummaryThe ubiquitin-proteasome system is essential for maintaining protein homeostasis. However, proteasome dysregulation in chronic diseases is poorly understood. Through genome-wide cell-based screening using 5,500 cDNAs, a signaling pathway leading to NFκB activation was selected as an inhibitor of 26S proteasome. TNF-α increased S5b (HGNC symbol PSMD5; hereafter S5b/PSMD5) expression via NFκB, and the surplus S5b/PSMD5 directly inhibited 26S proteasome assembly and activity. Downregulation of S5b/PSMD5 abolished TNF-α-induced proteasome inhibition. TNF-α enhanced the interaction of S5b/PSMD5 with S7/PSMC2 in nonproteasome complexes, and interference of this interaction rescued TNF-α-induced proteasome inhibition. Transgenic mice expressing S5b/PSMD5 exhibited a reduced life span and premature onset of aging-related phenotypes, including reduced proteasome activity in their tissues. Conversely, S5b/PSMD5 deficiency in Drosophila melanogaster ameliorated the tau rough eye phenotype, enhanced proteasome activity, and extended the life span of tau flies. These results reveal the critical role of S5b/PSMD5 in negative regulation of proteasome by TNF-α/NFκB and provide insights into proteasome inhibition in human disease