Induction of cytokines in a human colon epithelial cell line by Shiga toxin 1 (Stx1) and Stx2 but not by non-toxic mutant Stx1 which lacks N-glycosidase activity

Stx1 and Stx2 produced by Shiga toxin-producing Escherichia coli are cytotoxic due to their N-glycosidase activity on 28S rRNA. In this study, we have shown that proinflammatory cytokine mRNAs, especially IL-8, were induced by Stx1 and Stx2 in Caco-2 cells. A non-toxic mutant of Stxl which lacks N-glycosidase activity did not induce cytokine mRNAs. IL-8 production at the protein level was enhanced by Stx1 and Stx2, but not by the mutant Stx1. These results demonstrate that Shiga toxins induce expression and synthesis of cytokines in Caco-2 cells and their N-glycosidase activity is essential for the induction.     

超细人工皮革生产的先进技术

分析了目前人工皮革市场的情况,并对不同的人造皮革生产技术进行了评估。提出生产环保效应佳的高级人工皮革产品的良好解决方案是将水刺技术运用于可回收利用的PET超细纤维加工工艺中。具有多年实践经验的Trad ik公司,其技术可作为未来投资人工皮革生产的一种选择。     

Viscoelastic Liquid Matrix with Faster Bulk Relaxation Time Reinforces the Cell Cycle Arrest Induction of the Breast Cancer Cells via Oxidative Stress

The reactivating of disseminated dormant breast cancer cells in a soft viscoelastic matrix is mostly correlated with metastasis. Metastasis occurs due to rapid stress relaxation owing to matrix remodeling. Here, we demonstrate the possibility of promoting the permanent cell cycle arrest of breast cancer cells on a viscoelastic liquid substrate. By controlling the molecular weight of the hydrophobic molten polymer, poly(ε-caprolactone-co-D,L-lactide) within 35–63 g/mol, this study highlights that MCF7 cells can sense a 1000 times narrower relaxation time range (80–290 ms) compared to other studies by using a crosslinked hydrogel system. We propose that the rapid bulk relaxation response of the substrate promotes more reactive oxygen species generation in the formed semi-3D multicellular aggregates of breast cancer cells. Our finding sheds light on the potential role of bulk stress relaxation in a viscous-dominant viscoelastic matrix in controlling the cell cycle arrest depth of breast cancer cells.     

Synthesis and characterization of poly(vinyl alcohol) carbonate

Poly(vinyl alcohol) (PVA) was reacted with dimethyl carbonate (DMC) to prepare PVA carbonate (PVAC), which is considered to have three structures, cyclic carbonate (I), monocarbonate (II) and crosslinking carbonate (III). Though the reaction proceeded easily in dimethyl sulfoxide at 120 °C without any catalyst, the yield of the ethanol‐insoluble part of the products was less than that with the reaction containing a catalyst such as tetrabutylammonium bromide (TBAB). TBAB concentration did not affect the rate of carbonic esterification but affected the yield of the ethanol‐insoluble part. The rate of carbonic esterification increased with an increase in reaction temperature, and the activation energy of this reaction was 114 kJ mol⁻¹. Carbonic esterification under reduced pressure showed a larger degree of esterification than that of the reaction under atmospheric pressure. PVAC was soluble in water at a low degree of carbonic esterification (DC) but became insoluble as DC increased. The thermal property of PVA reduced by the carbonic esterification was improved as DC increased. © 2000 Society of Chemical Industry     

日本湿巾市场—— 以消毒湿巾为主导,近两年加速增长

因为新冠肺炎疫情的影响,人们对口罩和医用防护服的需要持续扩大,因此非织造布材料的需求大幅增长.随着消费者注重清洁以及预防新冠病毒感染的意识增强,日本的湿巾市场也快速增长.从2020年初起,该国消毒湿巾和其他种类湿巾的需求飙升.     

Empirical correlations for predicting the self-leveling behavior of debris bed

Studies on the self-leveling behavior of debris bed are crucial for the assessment of core-disruptive accident (CDA) occurred in sodium-cooled fast reactors (SFR). To clarify this behavior over a comparatively wider range of gas velocities, a series of experiments were performed by injecting nitrogen gas uniformly from a pool bottom. Current experiments were conducted in a cylindrical tank, in which water, nitrogen gas and different kinds of solid particles, simulate the coolant, vapor (generated by coolant boiling) and fuel debris, respectively. Based on the quantitative data obtained (mainly the time variation of bed inclination angle), with the help of dimensional analysis technique, a set of empirical correlations to predict the self-leveling development depending on particle size, particle density and gas injection velocity was proposed and discussed. It was seen that good agreement could be obtained between the calculated and experimental values. Rationality of the correlations was further confirmed through detailed analyses of the effects of experimental parameters such as particle size, particle density, gas flow rate and boiling mode. In order to facilitate future analyses and simulations of CDAs in SFRs, the obtained results in this work will be utilized for the validations of an advanced fast reactor safety analysis code.     

Development of hybrid reprocessing technology based on solvent extraction and pyro-chemical electrolysis

Toshiba has been proposing a new fuel cycle concept for the transition period from Light Water Reactors (LWRs) to Fast Reactors (FRs). This concept involves a more valuable process for LWR spent-fuel reprocessing than the conventional process and improved proliferation resistance. We have been developing a new technology, the Toshiba Hybrid Reprocessing Process, based on solvent extraction and pyro-chemical electrolysis, for spent fuel reprocessing for the transition period from LWRs to FRs. The Toshiba Hybrid Reprocessing Process combines the solvent extraction process of the LWR spent fuel in nitric acid with the recovery of high-purity uranium (U) and the pyro-chemical process in molten salts for recovery of impure plutonium with minor actinides (Pu + MA). High-purity U is used for LWR fuel, and impure Pu + MA is used for metallic FR fuel. Valence control by the electrolysis and solvent extraction tests using LWR spent fuel and oxalate precipitation tests were carried out to confirm the feasibility of the Toshiba Hybrid Reprocessing Process. A consecutive processing equipment for the solvent extraction process and a bench-scale apparatus for the pyro-chemical process were manufactured. The consecutive processing equipment consists of a flow type electrolytic cell and a centrifugal extractor. The test revealed that U of 99.99% of purity was recovered. The bench-scale apparatus consists of a reactor for oxalate precipitation, a solid-liquid separator in which nitric acid with fission products and precipitation are separated, and a drying equipment in which the precipitation is dry. Precipitation test with neodymium (Nd) which is simulated as Pu + MA in nitric acid was carried out. It was confirmed that precipitation ratio of Nd was more than 99.9% and that moisture ratio of the precipitation was less than 10%. The results suggested that U recovery of LWR spent fuel was 99.99% with the consecutive processing equipment and Pu + MA recovery was more than 99.9% with the bench-scale apparatus. The Toshiba Hybrid Reprocessing Process could recover high-purity U used for LWR fuel, and impure Pu + MA used for metallic FR fuel.     

Equilibrium properties and crystal growth of D2O + cyclopentane hydrate for sustainable tritium separation

This study reports thermodynamic properties and crystal growth observations of D₂O + cyclopentane hydrate toward the development of a hydrate-based tritium separation process. We employed D₂O as a host of hydrate with respect to the investigation into the formation of D₂O hydrate substrate, which is a core component of the tritium separation process. The hydrate phase equilibrium temperature in the liquid D₂O + liquid cyclopentane system was 3.2°C higher than the corresponding H₂O hydrate. Experiments on crystal growth were conducted at temperatures ranging from 5.1 to 8.5°C under atmospheric pressure. Under each thermodynamic condition, polygonal hydrate crystals appeared, growing along the D₂O/cyclopentane interface. The geometric shape and size of the crystals varied depending on the temperature. The variation in crystal morphology was comparable to that of the H₂O + cyclopentane hydrate. Implications based on the obtained results for the hydrate-based isotopic water separation process design are discussed.     

Syntrophic degradation of proteinaceous materials by the thermophilic strains Coprothermobacter proteolyticus and Methanothermobacter thermautotrophicus

Protein is a major component of organic solid wastes, and therefore, it is necessary to further elucidate thermophilic protein degradation process. The effects of hydrogenotrophic methanogens on protein degradation were investigated using the proteolytic bacterial strain CT-1 that was isolated from a methanogenic thermophilic (55°C) packed-bed reactor degrading artificial garbage slurry. Strain CT-1 was closely related to Coprothermobacter proteolyticus, which is frequently found in methanogenic reactors degrading organic solid wastes. Strain CT-1 was cultivated in the absence or presence of Methanothermobacter thermautotrophicus by using 3 kinds of proteinaceous substrates. Degradation rates of casein, gelatin, and bovine serum albumin were higher in co-cultures than in monocultures. Strain CT-1 showed faster growth in co-cultures than in monocultures. M. thermautotrophicus comprised 5.5-6.0% of the total cells in co-culture. Increased production of ammonia and acetate was observed in co-cultures than in monocultures, suggesting that addition of M. thermautotrophicus increases the products of protein degradation. Hydrogen produced in the monocultures was converted to methane in co-cultures. These results suggest that thermophilic proteolytic bacteria find it favorable to syntrophically degrade protein in a methanogenic environment, and that it is important to retain hydrogen-scavenging methanogens within the reactor.     

Simple immunoassay for detection of PCBs in transformer oil

A rapid and inexpensive procedure to detect polychlorinated biphenyls (PCBs) in transformer oil is needed to facilitate identification and removal of PCB contaminated transformers. Here we describe a simple two-step liquid-liquid extraction using acidic dimethyl sulfoxide in conjunction with an immunoassay for detecting PCBs in transformer oil. The process described is faster and simpler than any previous immunoassay while maintaining comparable detection limit and false negative rate. Cross reactivity data, characterizing the immunoassay response to the four Kanechlor technical mixtures of PCBs in oil, are presented. Forty-five used transformer oil samples were analyzed by gas chromatography-high-resolution mass spectrometry and were also evaluated using the immunoassay protocol developed. Results presented show zero false negatives at a 1.4 ppm nominal cutoff for the transformer oils analyzed.