Effects of gonadotrophin treatments on meiotic and developmental competence of oocytes in porcine primordial follicles following xenografting to nude mice

Our objective was to improve the developmental ability of oocytes in porcine primordial follicles xenografted to nude mice, by treating the host mice with gonadotrophins to accelerate follicular growth. Ovarian tissues from 20-day-old piglets, in which most of the follicles were primordial, were transplanted under the kidney capsules of ovariectomized nude mice. Gonadotrophin treatments were commenced around 60 days after vaginal cornification in the mice. Ovarian grafts were obtained 2 or 3 days after treatment with equine chorionic gonadotrophin (eCG-2 and eCG-3 groups), after porcine FSH infusion for 7 or 14 days, or after infusion of porcine FSH for 14 days with a single injection of estradiol antiserum (FSH-7, FSH-14 and FSH-14EA groups, respectively). Gonadotrophin treatments accelerated follicular growth within the xenografts compared with that in control mice given no gonadotrophins, consistent with higher (P < 0.05) circulating inhibin levels in the gonadotrophin-treated mice. In contrast, circulating mouse FSH levels were significantly (P < 0.05) depressed. We recovered large numbers of full-sized oocytes with meiotic competence to the mature stage from the eCG-3, FSH-7, and FSH-14EA, unlike in the control group. Moreover, 56% of matured oocytes with the first polar body (n = 39) were fertilized in vitro in the FSH-14EA group. After in vitro fertilization and subsequent culture for 7 days, one blastocyst was obtained from each of the eCG-3, FSH-7 and, FSH-14EA groups, whereas no blastocysts appeared in the other groups. Exogenous gonadotrophins--not mouse FSH--stimulated the growing follicles that had developed from the primordial follicles in the xenografts: the effects were incomplete but improved to some extent the meiotic and developmental abilities of the oocytes.     

Numerical Simulation and Experiment on the Transport of Fine Particles in a Ventilated Room

ABSTRACT

The change in concentration distribution of particulate contaminants emitted in a room was studied experimentally and theoretically to investigate whether the transport of contaminants in a room with a source of particles can be predicted by numerical simulation. Tracer contaminants, monodisperse latex particles, were introduced into a 3.3 m ×2.7 m ×2 m room with clean air for a given time, and the change in the contaminant concentrations with time was measured at various positions in the room. Calculations of the spatial and temporal distributions in the gas velocity and contaminant concentration were performed to predict the concentration change, with the Navier-Stokes and convection-diffusion equations solved numerically. The experimental results showed that the concentration distribution depends on the position of introduction of the contaminants. It was also indicated that the contaminants introduced near the room floor diffuse more than predicted. However, the calculated concentrations agreed almost quantitatively with the measured results, except near the floor and walls. The change in the concentration with time and the dependence of the concentration distribution on the position of the particle source were well reproduced by the calculation.     

Artificial Intelligence-based determination of fracture toughness and bending strength of silicon nitride ceramics

Two mechanical properties, fracture toughness (K_IC) and bending strength (σ), of silicon nitride (Si₃N₄) ceramics were determined from their microstructural images via convolutional neural network (CNN) models. The Si₃N₄ samples used for database were fabricated using various kinds of sintering additives under different process conditions. In total, 330 data sets were prepared and used for building the CNN models for artificial intelligence-bassed determination of the two mechanical properties and testing the determination accuracy of the trained models. The determination coefficients (R²), which were used as accuracy indices, were approximately 0.85 for K_IC and 0.92 for σ. Although both the R² values were relatively high, the lower value for K_IC suggests that it is influenced more by what is little obtained from the microstructural information, such as grain-boundary characteristics. Furthermore, gradient-weighted class activation mapping, which can visualize which parts of the image the CNN models focus on, showed that the trained models determined the two mechanical properties based on correct recognition of the microstructural difference among the images.     

Synthesis and catalytic activity of the thermoresponsive polymers having pyrrolidine side chains as base functionalities

Optically active polymers having chiral 2‐aminomethylpyrrolidine side chains have been newly synthesized by a radical homopolymerization of the corresponding protected acrylamide monomer and copolymerization with N‐isopropylacrylamide followed by deprotection. The resulting polymers were found to be thermoresponsive showing lower critical solution temperatures (LCSTs) at 27–65°C in their aqueous solutions. The pyrrolidine side chains of the resulting thermoresponsive polymer promoted aldol reaction between cyclohexanone and p‐nitrobenzaldehyde in water, and the reaction proceeded most smoothly at its LCST. Moreover, the diastereomeric ratio (syn : anti) of the aldol adducts obtained at the reaction at 40°C was 22 : 78, whereas the diastereomeric ratio (syn : anti) was 55 : 45 at 20°C. These results indicate that the pyrrolidine side chains catalyze the aldol reactions in the relatively hydrophobic field generated by the thermoresponsive polymer at its LCST. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and proton conductivity of phosphoric acid‐doped blend membranes composed of sulfonated block copolyimides and polybenzimidazole

A series of phosphoric acid (PA)‐doped blend membranes composed of block or random sulfonated polyimides (SPIs) and polybenzimidazole (PBI) were prepared with similar PA contents to investigate the influence of chemical structures of SPIs on proton conductivity. The proton conductivity of a PA‐doped blend membrane containing block‐type SPI, PA‐bSPI(80/20)/oPBI, was higher than that of the corresponding pristine block‐type SPI, PA‐SPI/PBI containing random‐type SPI and Nafion membranes over a wide temperature range, and reached 0.37 S cm^?1 at 90 °C and 98% relative humidity. The PA‐bSPI(80/20)/oPBI membrane also showed distinct proton conductivity even at low humidity due to a new proton transport pathway among PA and sulfonic acid groups. Also, the novel PA‐doped blend membrane showed higher proton conductivity than Nafion at both above 100 °C and below 0 °C under low relative humidity conditions. © 2013 Society of Chemical Industry     

The effect of electrically charged dielectric walls on the diffusive deposition of submicron aerosol particles

The effect of an electrical charge on a dielectric wall on the deposition of charged aerosol particles is investigated. The dielectric walls used in the deposition experiments, poly(vinyl chloride) or polytetrafluoroethylene disks, are prepared to have known uniform surface charge distributions by using a corona discharge procedure. This avoids any effects on deposition caused by nonuniformity of the surface charge. The surface charge densities are based on measurements of the surface voltage in the center of the sample. Deposition experiments using a turbulently-mixed stirred tank demonstrate that particle deposition rates to the wall decrease as the sample's thickness increases or its relative permittivity decreases, even at a constant surface voltage. The electric field over the sample wall is calculated using the surface charge density, and the convection-diffusion equations describing particle deposition by Brownian and turbulent diffusion and electric migration are solved numerically. The calculated deposition rates agree well with those measured, indicating that quantitative prediction of particle deposition is possible if the surface charge, material, thickness and the effect of adjacent walls are taken into account.     

Effect of Different Filler Contents and Printing Directions on the Mechanical Properties for Photopolymer Resins

Photopolymer resins are widely used in the production of dental prostheses, but their mechanical properties require improvement. We evaluated the effects of different zirconia filler contents and printing directions on the mechanical properties of photopolymer resin. Three-dimensional (3D) printing was used to fabricate specimens using composite photopolymers with 0 (control), 3, 5, and 10 wt.% zirconia filler. Two printing directions for fabricating rectangular specimens (25 mm × 2 mm × 2 mm) and disk-shaped specimens (φ10 mm × 2 mm) were used, 0° and 90°. Three-point bending tests were performed to determine the flexural strengths and moduli of the specimens. The Vickers hardness test was performed to determine the hardness of the specimens. Tukey’s multiple comparison tests were performed on the average values of the flexural strengths, elastic moduli, and Vickers hardness after one-way ANOVA (α = 0.05). The flexural strengths and elastic moduli at 0° from high to low were in the order of 0, 3, 10, and 5 wt.%, and those at 90° were in the order of 3, 0, 10, and 5 wt.% (p < 0.05). For 5 and 10 wt.%, no significant differences were observed in mechanical properties at 0° and 90° (p < 0.05). The Vickers hardness values at 0° and 90° from low to high were in the order of 0, 3, 5, and 10 wt.% (p < 0.05). Within the limits of this study, the optimal zirconia filler content in the photopolymer resin for 3D printing was 0 wt.% at 0° and 3 wt.% at 90°.     

Oxidative Desulfurization‐Fluorination: A Facile Entry to a Wide Variety of Organofluorine Compounds Leading to Novel Liquid‐Crystalline Materials

The oxidative desulfurization‐fluorination reaction of organosulfur compounds using an N‐haloimide and a fluoride source is demonstrated to be an effective and mild fluorinaton method that allows us to synthesize in high yields with high chemoselectivity various types of gem‐difluoro compounds, trifluoromethyl‐substituted (hetero)aromatics, trifluoromethyl ethers, and N‐trifluoromethylanilines. Herein briefly summarized are the synthetic procedures as well as the scope and limitations of the reaction. The applicability of the reaction is demonstrated by the synthesis of a difluorinated glutamic acid and novel liquid‐crystalline materials having an N‐trifluoromethylamino, trifluoromethoxy, or 1,2‐difluoroethylene group. The fluorine‐containing liquid‐crystalline materials are compared with the corresponding non‐fluorinated materials in respect to phase transition behaviors and electro‐optical properties and shown to be suitable for not only super twisted nematic (STN) but also for thin film transistor (TFT)‐addressed liquid crystals displays. 1. Introduction 2. Fluorination Reactions 2.1 Fluorination of Sulfides and Thiols 2.2 Fluorination of Dithioacetals 2.3 Oxidative Desulfurization‐Fluorination of Dithioester and Orthothioester 2.4 Synthesis of Trifluoromethyl Ethers from Dithiocarbonates 2.5 Oxidative Desulfurization‐Fluorination of Thionesters and Thioncarbonates 2.6 Synthesis of Trifluoromethylamines from Dithiocarbamates 3. Synthesis and Electro‐Optical Properties of Novel Fluorine‐Containing Liquid Crystals 3.1 Synthesis and Electro‐Optical Properties of N‐Trifluoromethylamino‐Substituted Liquid Crystals 3.2 Syntheses and Electro‐Optical Properties of Liquid Crystals having Trifluoromethoxy Polar Functional Group 3.3 Synthesis and Properties of 3‐Substituted Phenyl Trifluoromethyl Ethers 3.4 Synthesis and Electro‐Optical Properties of Liquid Crystals with a vic‐Difluoro‐Olefinic Moiety