Polyphenols Extracted from Black Tea (Camellia sinensis) Residue by Hot‐Compressed Water and Their Inhibitory Effect on Pancreatic Lipase in vitro

Abstract: Polyphenols, retained in black tea wastes following the commercial production of tea beverages, represent an underutilized resource. The purpose of this study was to investigate the potential use of hot‐compressed water (HCW) for the extraction of pancreatic lipase‐inhibiting polyphenols from black tea residues. Black tea residues were treated with HCW at 10 °C intervals, from 100 to 200 °C. The resulting extracts were analyzed using high‐performance liquid chromatography‐mass spectrometry and assayed to determine their inhibitory effect on pancreatic lipase activity in vitro. Four theaflavins (TF), 5 catechins, 2 quercetin glycosides, quinic acid, gallic acid, and caffeine were identified. The total polyphenol content of extracts increased with increasing temperature but lipase inhibitors (TF, theaflavin 3‐O‐gallate, theaflavin 3′‐O‐gallate, theaflavin 3,3′‐O‐gallate, epigallocatechin gallate, and epicatechin gallate) decreased over 150 °C. All extracts inhibited pancreatic lipase but extracts obtained at 100 to 140 °C showed the greatest lipase inhibition (IC₅₀s of 0.9 to 1.3 μg/mL), consistent with the optimal extraction of TFs and catechins except catechin by HCW between 130 and 150 °C. HCW can be used to extract pancreatic lipase‐inhibiting polyphenols from black tea waste. These extracts have potential uses, as dietary supplements and medications, for the prevention and treatment of obesity. Practical Application: Active forms of lipase inhibitors can be recovered from black tea residues. They could be used as dietary supplements or medications.     

Reduction of Vibration in Concentrated Winding Permanent Magnet Synchronous Motor by Means of Skew Effects of Rotor

Global warming and the problem of successfully incorporating environmental safeguards are promoting the need for a more power‐efficient motor. Therefore, as a driving source, permanent magnet synchronous motors (PMSMs) with concentrated winding are widely used in a variety of fields. However, a PMSM with a concentrated winding generates more vibration than one with a distributed winding because of the radial electromagnetic force. This paper describes the effect of a new skewed rotor on the characteristics of a concentrated winding PMSM. We investigated this effect by three‐dimensional finite element method (3D FEM) analysis and measurement. We also demonstrate that the proposed rotor is effective in reducing the radial electromagnetic force without decreasing motor efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(2): 33–43, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22400     

Epitaxial p-type SiC as a self-driven photocathode for water splitting

Solar-to-hydrogen conversion efficiencies of water-splitting photochathodes using epitaxially grown p-type 4H-, 6H- and 3C-SiC were estimated in a two-electrode system without applying any external bias. By using electrode materials with small oxygen overpotentials as counter electrodes, the photocurrent became comparable to that observed in a three-electrode system with a suitable bias. Estimated efficiencies seem to depend on the bandgap of the SiC polytypes. For the 3C-SiC, the obtained efficiency was 0.38%, which is so far the highest value reported for SiC. We confirmed that the hydrogen volumes estimated from the photocurrent were almost the same as actual volumes observed by gas chromatography.     

Impact of Dynamic Interlayer Interactions on Thermal Conductivity of Ca3Co4O9

The phonon thermal conductivity of misfit-layered Ca₃Co₄O₉ has been calculated by perturbed molecular dynamics using a classical force field. Detailed numerical analyses reveal that, in spite of its smaller cross-sectional area, the CoO₂ layer transports more heat than the thicker rock salt (RS) layer, although its local thermal conduction is more suppressed than in another layered cobaltite, Na _x CoO₂. The origins of these differences have been elucidated through careful examination of the atomic arrangements in each layer. Since thermal conduction in the RS layer can be reduced without deteriorating electronic properties for which the CoO₂ layer is responsible, it is suggested that the RS layer should be modified to further suppress the overall in-plane thermal conductivity. Computational experiments with increasing number of Ca–O planes in the RS layer showed the opposite trend to what can be predicted based on the misfit between two dissimilar layers. Further analyses to reveal the origin of these unexpected results provide yet another strategy to further decrease the thermal conductivity, namely to control the dynamic interference between atoms across the interface between two layers.     

MicroRNA-331-3p Suppresses Cervical Cancer Cell Proliferation and E6/E7 Expression by Targeting NRP2

Aberrant expression of microRNAs (miRNAs) is involved in the development and progression of various types of cancers. In this study, we investigated the role of miR-331-3p in cell proliferation and the expression of keratinocyte differentiation markers of uterine cervical cancer cells. Moreover, we evaluated whether neuropilin 2 (NRP2) are putative target molecules that regulate the human papillomavirus (HPV) related oncoproteins E6 and E7. Cell proliferation in the human cervical cancer cell lines SKG-II, HCS-2, and HeLa was assessed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. Cellular apoptosis was measured using the TdT-mediated dUTP nick end labeling (TUNEL) and Annexin V assays. Quantitative RT-PCR was used to measure the messenger RNA (mRNA) expression of the NRP2, E6, E7, p63, and involucrin (IVL) genes. A functional assay for cell growth was performed using cell cycle analyses. Overexpression of miR-331-3p inhibited cell proliferation, and induced G2/M phase arrest and apoptosis in SKG-II, HCS-2 and HeLa cells. The luciferase reporter assay of the NRP2 3′-untranslated region revealed the direct regulation of NRP2 by miR-331-3p. Gene expression analyses using quantitative RT-PCR in SKG-II, HCS-2, and HeLa cells overexpressing miR-331-3p or suppressing NRP2 revealed down-regulation of E6, E7, and p63 mRNA and up-regulation of IVL mRNA. Moreover, miR-331-3p overexpression was suppressed NRP2 expression in protein level. We showed that miR-331-3p and NRP2 were key effectors of cell proliferation by regulating the cell cycle, apoptosis. NRP-2 also regulates the expression of E6/E7 and keratinocyte differentiation markers. Our findings suggest that miR-331-3p has an important role in regulating cervical cancer cell proliferation, and that miR-331-3p may contribute to keratinocyte differentiation through NRP2 suppression. miR-331-3p and NRP2 may contribute to anti-cancer effects.     

Terminal defined chain-growth polycondensation of 4-chloropyridine

This work examines the polycondensation of 4-chloropyridine derivatives using an N-(4-tert-butylbenzyl)-4-chloropyridinium (BPymCl) initiator and ion exchange reagents NaBPh₄, NaBF₄, and TBABF₄. The ¹H NMR spectra demonstrate that the product quantity is proportional to the total conversion of the monomer and the initiator. The MALDI-TOF MS spectrum shows that the product contains more than 9 monomer units. The polymerization was well-terminated via the addition of dimethylaminopyridine. These results indicate that the polycondensation proceeds in a chain-growth manner. This polycondensation could be a new example of a controlled polymerization with a well-defined end group.     

Tribochemical behaviour and lubrication characteristics of aromatic compounds

Radical scavenger, radical anion scavenger, and peroxide decomposer were added to aromatic hydrocarbons and phosphates in aromatic rings with and without side chain, and the effect of these inhibitors on tribopolymerisation and the lubrication characteristics of the aromatic compounds were investigated, in various atmospheres, in order to clarify the reaction mechanism. The aromatics of both hydrocarbons and phosphates with a methyl group in aromatic rings react readily at the rubbing surfaces to form polymer or polymer-like products, improving the lubricating characteristics. The tribochemical reactions of alkylaromatic compounds is shown to differ from those of trialkyl or triarylphosphates. It was concluded that the reaction proceeds through the radical or radicalanion and via peroxide to cause polymerisation.     

Round robin on indentation fracture resistance of silicon carbide ceramics by using a powerful optical microscope

Reproducibility of indentation fracture resistance, K_IFR of silicon carbides sintered with B and C was evaluated by a round robin with ten laboratories. When the crack length was measured with an optical microscope at a low magnification of ～100×, K_IFR varied widely from 3.43 to 4.20 MPa m^1/2, whereas those obtained by a powerful microscopy with both an objective lens of 40× and a traveling stage exhibited a consistent value of 3.20±0.12 MPa m^1/2. The wide scatter of K_IFR for the former measurements was attributed mainly to the variation in misreading of the crack length. It was revealed that the high resolving power of the objective lens of 40× enabled to find exact crack tips easily, which resulted in the good matching of K_IFR between laboratories for the latter case. It was suggested that the observation of indentations with powerful optics was effective for improving the reproducibility of the IF method.     

Supercritical fluid extraction of fungal oil using CO2, N2O,CHF3 and SF6

The extraction of oil from fungi (Mortierella ramanniana var.angulispora) was studied using carbon dioxide (CO₂), nitrous oxide (N₂O), trifluoromethane (CHF₃) and sulfur hexafluoride (SF₆) under supercritical conditions. The oil solubility was highest in SC-N₂O followed by SC-CO₂, while both SC-CHF₃ and SC-SF₆ showed poorer solvent power. The recorded oil solubilities at 333 K and 24.5 MPa were 2.3 wt% in N₂O, 0.48 wt% in CO₂, 0.0099 wt% in CHF₃ and 0.0012 wt% in SF₆. The oil solubilities in SC-N₂O and SC-CO₂ were measured over the pressure range 15.7–29.4 MPa and at temperatures ranging from 313–353 K. N₂O always showed greater solvent power than did CO₂ at the same temperature and pressure. The solvent power of a supercritical fluid increases with density at a given temperature, and increases with temperature at constant density. The change in neutral lipid composition of the extracted oil with the extraction ratio was measured. Free fatty acids or diglycerides were extracted more easily than triglycerides or sterol esters. The change in fatty acid composition was also measured. The proportion of γ-linolenic acid in the extract remained constant throughout the extraction.     

汽车电子连接器的力学机理研究——截面针型连接器设计参数的灵敏度分析

以连接端子、印刷电路板和电镀通孔3种不同材料构成的一种可拔插截面针型汽车电子连接器为研究对象,为满足其在非塑性状态下相互接触实现可反复拔插、稳定低电阻的连接要求。针对连接可靠性设计问题,利用接触动力学理论,对基于设计参数变化的连接器米赛斯应力和接触应力分布进行了解析和灵敏度分析,得到了影响其连接性能的关键设计参数。文中为减少高精度设计参数灵敏度解析的计算时间,提出了将连接端子前、后段形态设计参数分离的解析法,即在接触力学解析过程中,首先以准静态接触方法对连接端子后段(连接形态)设计参数进行接触力学解析,再以动态接触方法对连接端子前段(插拔形态)设计参数进行接触力学解析的方法。其结果对同类微小型可拔插截面针型汽车电子连接器设计参数的确定具有参考价值。