Synthesis and functionality of poly(N-vinylalkylamide). X. A novel aqueous two-phase system based on thermosensitive polymers and dextran

The use of thermosensitive polymers in an aqueous two-phase system was studied. Poly(N-isopropylacrylamide) (PNIPAAm) and poly(N-vinylisobutyramide) (PNVIBA) were used as thermosensitive polymers. Both polymers could form aqueous two-phase with dextran, respectively. The phase diagrams of each system were successfully obtained. Using myoglobin as a model protein, a preliminary separation study was performed. The separation ability of both polymers was higher than that from the poly(ethylene glycol)-dextran system. Protein separation ability appeared to be related to the hydrophilic/hydrophobic balance of the polymers. Both PNVIBA and PNIPAAm rich phases maintained their thermosensitivity after two-phase formation. PNVIBA and PNIPAAm are useful as polymers for a functional aqueous two-phase system. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2545–2548, 1999     

Adiabatic efficiency and Joule dissipation in supersonic Faraday MHD generator

The adiabatic efficiency of a supersonic Faraday MHD (magnetohydrodynamic) generator and its relation to Joule dissipation in the MHD channel were studied in a shock tube experiment. An adiabatic efficiency of 39.7% was obtained at enthalpy extraction of 8.3%. A dissipation process, which reduces the adiabatic efficiency, is examined by evaluating loading parameters and entropy production caused by Joule dissipation. At low load resistance, large Faraday currents in the channel upstream cause extremely large Joule dissipation in both the main flow and the region near the electrodes. It is confirmed experimentally that a high loading parameter yields a high adiabatic efficiency because Joule dissipation is small throughout the MHD channel. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 47–54, 1999     

Effects of fluid flow on the performance of a subsonic nonequilibrium disk MHD generator

The fluid flow and performance of a nonequilibrium disk MHD generator with subsonic flow are examined by time‐dependent two‐dimensional r–z numerical simulations. It is found that the development of the boundary layer is enhanced with increasing load resistance, as is the case in supersonic generators. The development of the boundary layer affects not only the performance of the generator but the thermal input to it, in contrast to supersonic generators. These facts lead to considerable departures from the performance predicted by a quasi‐one‐dimensional simulation and suggest that two‐dimensional design of the generator channel, taking account of boundary layer development, is necessary in order to assure high performance of a subsonic generator. © 2000 Scripta Technica, Electr Eng Jpn, 133(3): 18–25, 2000     

Genetic Analysis of Hexaploid Wheat (Triticum aestivum L.) Using the Complete Sequencing of Chloroplast DNA and Haplotype Analysis of the Wknox1 Gene

The aim of the presented study is a genetic characterization of the hexaploid wheat Triticum aestivum L. Two approaches were used for the genealogical study of hexaploid wheats—the complete sequencing of chloroplast DNA and PCR-based haplotype analysis of the fourth intron of Wknox1d and of the fifth-to-sixth-exon region of Wknox1b. The complete chloroplast DNA sequences of 13 hexaploid wheat samples were determined: Free-threshing—T. aestivum subsp. aestivum, one sample; T. aestivum subsp. compactum, two samples; T. aestivum subsp. sphaerococcum, one sample; T. aestivum subsp. carthlicoides, four samples. Hulled—T. aestivum subsp. spelta, three samples; T. aestivum subsp. vavilovii jakubz., two samples. The comparative analysis of complete cpDNA sequences of 20 hexaploid wheat samples (13 samples in this article plus 7 samples sequenced in this laboratory in 2018) was carried out. PCR-based haplotype analysis of the fourth intron of Wknox1d and of the fifth-to-sixth exon region of Wknox1b of all 20 hexaploid wheat samples was carried out. The 20 hexaploid wheat samples (13 samples in this article plus 7 samples in 2018) can be divided into two groups—T. aestivum subsp. spelta, three samples and T. aestivum subsp. vavilovii collected in Armenia, and the remaining 16 samples, including T. aestivum subsp. vavilovii collected in Europe (Sweden). If we take the cpDNA of Chinese Spring as a reference, 25 SNPs can be identified. Furthermore, 13–14 SNPs can be identified in T. aestivum subsp. spelta and subsp. vavilovii (Vav1). In the other samples up to 11 SNPs were detected. 22 SNPs are found in the intergenic regions, 2 found in introns, and 10 SNPs were found in the genes, of which seven are synonymous. PCR-based haplotype analysis of the fourth intron of Wknox1d and the fifth-to-sixth-exon region of Wknox1b provides an opportunity to make an assumption that hexaploid wheats T. aestivum subsp. macha var. palaeocolchicum and var. letshckumicum differ from other macha samples by the absence of a 42 bp insertion in the fourth intron of Wknox1d. One possible explanation for this observation would be that two Aegilops tauschii Coss. (A) and (B) participated in the formation of hexaploids through the D genome: Ae. tauschii (A)—macha (1–5, 7, 8, 10–12), and Ae. tauschii (B)—macha M6, M9, T. aestivum subsp. aestivum cv. ‘Chinese Spring’ and cv. ‘Red Doly’.     

Prediction Models for Agonists and Antagonists of Molecular Initiation Events for Toxicity Pathways Using an Improved Deep-Learning-Based Quantitative Structure–Activity Relationship System

In silico approaches have been studied intensively to assess the toxicological risk of various chemical compounds as alternatives to traditional in vivo animal tests. Among these approaches, quantitative structure–activity relationship (QSAR) analysis has the advantages that it is able to construct models to predict the biological properties of chemicals based on structural information. Previously, we reported a deep learning (DL) algorithm-based QSAR approach called DeepSnap-DL for high-performance prediction modeling of the agonist and antagonist activity of key molecules in molecular initiating events in toxicological pathways using optimized hyperparameters. In the present study, to achieve high throughput in the DeepSnap-DL system–which consists of the preparation of three-dimensional molecular structures of chemical compounds, the generation of snapshot images from the three-dimensional chemical structures, DL, and statistical calculations—we propose an improved DeepSnap-DL approach. Using this improved system, we constructed 59 prediction models for the agonist and antagonist activity of key molecules in the Tox21 10K library. The results indicate that modeling of the agonist and antagonist activity with high prediction performance and high throughput can be achieved by optimizing suitable parameters in the improved DeepSnap-DL system.     

Synthesis and functionalities of poly(N-vinylalkylamide). VII. A novel aqueous two-phase systems based on poly(N-vinylacetamide) and dextran

It was found that a poly(N-vinylacetamide) (polyNVA)-dextran system formed two phases. The top was polyNVA-rich and the bottom phase was dextran-rich, which is the same as the poly(ethylene glycol) (PEG)-dextran system, and the phase separation occurred at a lower concentration than the PEG-dextran system. The protein separation in the polyNVA-dextran system was studied using myoglobin. Myoglobin was partitioned more in the bottom (dextran-rich) phase in a polyNVA-dextran system. The partition coefficient of the polyNVA-dextran system was smaller that of the PEG-dextran system, which suggests that the polyNVA-dextran system is superior to the PEG-dextran system for myoglobin separation. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 255–258, 1998     

Honokiol Acts as a Potent Anti-Fibrotic Agent in the Liver through Inhibition of TGF-β1/SMAD Signaling and Autophagy in Hepatic Stellate Cells

Chronic liver injury may result in hepatic fibrosis, which can progress to cirrhosis and eventually liver failure. There are no drugs that are specifically approved for treating hepatic fibrosis. The natural product honokiol (HNK), a bioactive compound extracted from Magnolia grandiflora, represents a potential tool in the management of hepatic fibrosis. Though HNK has been reported to exhibit suppressive effects in a rat fibrosis model, the mechanisms accounting for this suppression remain unclear. In the present study, the anti-fibrotic effects of HNK on the liver were evaluated in vivo and in vitro. In vivo studies utilized a murine liver fibrosis model, in which fibrosis is induced by treatment with carbon tetrachloride (CCl₄). For in vitro studies, LX-2 human hepatic stellate cells (HSCs) were treated with HNK, and expression of markers of fibrosis, cell viability, the transforming growth factor-β (TGF-β1)/SMAD signaling pathway, and autophagy were analyzed. HNK was well tolerated and significantly attenuated CCl₄-induced liver fibrosis in vivo. Moreover, HNK decreased HSC activation and collagen expression by downregulating the TGF-β1/SMAD signaling pathway and autophagy. These results suggest that HNK is a new potential candidate for the treatment of hepatic fibrosis through suppressing both TGF-β1/SMAD signaling and autophagy in HSCs.     

Infiltration and Pyrolysis of Polytitanocarbosilane in an Si-Ti-C-O Fabric/Mullite Porous Composite

Incorporating Si-Ti-C-O fabric into a mullite matrix is expected to increase the fracture energy of mullite ceramics. The present paper describes the processing of an Si-Ti-C-O fabric/mullite/polytitanocarbosilane composite. A polytitanocarbosilane (a precursor of Si-Ti-C-O fiber)/xylene solution was infiltrated into a laminated porous mullite composite with 35–37 vol% fabric and thermally decomposed to an amorphous solid at 1000°C, in an argon atmosphere, to decrease the porosity and residual stress induced by the difference in thermal and mechanical properties between the Si-Ti-C-O fabric and the mullite. The decrease in porosity of the composite with pyrolysis of the precursor polymer was analyzed theoretically, and those results were used to control the effective experimental parameters. The infiltration/pyrolysis process was repeated eight times to produce a composite of 90.4% theoretical density. The composite exhibited significant pseudoductility, with a fracture energy of 11.4 kJ/m² and a flexural strength of 290 MPa.     

Study on the propagation process of spontaneous vapor explosions and the behavior of induced pressure waves

Single-drop experiments are carried out with the object of studying the propagation process of a spontaneous vapor explosion and the behavior of pressure waves induced by the explosion. Both a molten tin drop-water system and the molten LiNC₃ drop-ethanol system are examined. Propagation of an explosion between two tin drops is confirmed in tin-water experiments, although the apparent propagation velocity is only about 5 m/s and the explosion behavior differs largely between the two drops. In the LiNC₃-ethanol system, the traveling behavior of the pressure wave in a one-dimensional channel is analyzed and the velocity through the interaction zone is measured. Full-time coherence is confirmed in a 25-drop experiment and it is revealed that the velocity depends largely on the development stage of the vapor explosion. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 76–87, 1996     

Study of impingement cooling of heat sinks for LSI packages with longitudinal fins

This paper describes an experimental and a semi-empirical study on the impingement cooling characteristics of heat sinks with longitudinal fins of a type suitable for LSI packages. The experiments were performed with a variety of different fins. To enhance impingement cooling, one long rectangular inlet orifice (slit) over the center of the heat sink was found to offer the best structure. The optimum orifice width is about 1/6 of the base width of the heat sink. The thermal resistance at a fixed volumetric flow rate and orifice width varies little with size of the gap between the fin tops and inlet orifice, but gaps near 2 mm slightly lower the resistance. Correlations are proposed between the thermal resistance of the heat sink and the geometry of the longitudinal fins. The accuracy of the predicted thermal resistances was found to be within ±25% of the experimental data. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(8): 537–553, 1996