VEGF and FGF2 Improve Revascularization,Survival, and Oocyte Quality of Cryopreserved,Subcutaneously-Transplanted Mouse Ovarian Tissues

This study was conducted to investigate the effect of the vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) on revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue. Autologous subcutaneous transplantation of vitrified-thawed mouse ovarian tissues treated with (experimental group) or without (control group) VEGF and FGF2 was performed. After transplantation to the inguinal region for two or three weeks, graft survival, angiogenesis, follicle development, and oocyte quality were examined after gonadotropin administration. VEGF coupled with FGF2 (VEGF/FGF2) promoted revascularization and significantly increased the survival rate of subcutaneously-transplanted cryopreserved ovarian tissues compared with untreated controls. The two growth factors did not show long-term effects on the ovarian grafts. In contrast to the untreated ovarian grafts, active folliculogenesis was revealed as the number of follicles at various stages and of mature oocytes in antral follicles after gonadotropin administration were remarkably higher in the VEGF/FGF2-treated groups. Although the fertilization rate was similar between the VEGF/FGF2 and control groups, the oocyte quality was much better in the VEGF/FGF2-treated grafts as demonstrated by the higher ratio of blastocyst development. Introducing angiogenic factors, such as VEGF and FGF2, may be a promising strategy to improve revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue.     

Improvement in the breakdown endurance of high-κ dielectric by utilizing stacking technology and adding sufficient interfacial layer

Improvement in the time-zero dielectric breakdown (TZDB) endurance of metal-oxide-semiconductor (MOS) capacitor with stacking structure of Al/HfO₂/SiO₂/Si is demonstrated in this work. The misalignment of the conduction paths between two stacking layers is believed to be effective to increase the breakdown field of the devices. Meanwhile, the resistance of the dielectric after breakdown for device with stacking structure would be less than that of without stacking structure due to a higher breakdown field and larger breakdown power. In addition, the role of interfacial layer (IL) in the control of the interface trap density (D_it) and device reliability is also analyzed. Device with a thicker IL introduces a higher breakdown field and also a lower D_it. High-resolution transmission electron microscopy (HRTEM) of the samples with different IL thicknesses is provided to confirm that IL is needed for good interfacial property.     

Scalable SIMD-parallel memory allocation for many-core machines

Dynamic memory allocation is an important feature of modern programming systems. However, the cost of memory allocation in massively parallel execution environments such as CUDA has been too high for many types of kernels. This paper presents XMalloc, a high-throughput memory allocation mechanism that dramatically magnifies the allocation throughput of an underlying memory allocator. XMalloc embodies two key techniques: allocation coalescing and buffering using efficient queues. This paper describes these two techniques and presents our implementation of XMalloc as a memory allocator library. The library is designed to be called from kernels executed by massive numbers of threads. Our experimental results based on the NVIDIA G480 GPU show that XMalloc magnifies the allocation throughput of the underlying memory allocator by a factor of 48.     

Note on eddy formation for stokes flows in circular cavities

Abstract

In this note, a simple model of a circular cavity with two arcs rotated in opposite directions on the boundary is employed to demonstrate flow patterns of recirculation. A particular streamline “cutting” the domain into two separating eddies is formed as a circular arc. When the rotating angular speed of the arc is proportional to the length of the arc, the streamline degenerates to a straight line.     

A note on a plane creeping corner flow

Abstract

A simple method of similarity transformation is formulated to analyze a two‐dimensional creeping corner flow. By this peculiar transformation, governing equations for the plane velocity are reduced to a pair of ordinary differential equations. With a particular selection of appropriate boundary conditions, the field variables of velocity, pressure, vorticity, and stream function are obtained analytically. A special case with constant velocity at one boundary is explored. The salient characteristics of this example are used to compare with previous investigations. The present study shows that both approaches provide exactly the same solutions. A very interesting feature is that the velocity components in the coordinate system are independent of the radial direction.     

Boundary element analysis for viscoelastic solids containing interfaces/holes/cracks/inclusions

With the aid of the elastic–viscoelastic correspondence principle, the boundary element developed for the linear anisotropic elastic solids can be applied directly to the linear anisotropic viscoelastic solids in the Laplace domain. Green's functions for the problems of two-dimensional linear anisotropic elastic solids containing holes, cracks, inclusions, or interfaces have been obtained analytically using Stroh's complex variable formalism. Through the use of these Green's functions and the correspondence principle, special boundary elements in the Laplace domain for viscoelastic solids containing holes, cracks, inclusions, or interfaces are developed in this paper. Subregion technique is employed when multiple holes, cracks, inclusions, and interfaces exist simultaneously. After obtaining the physical responses in Laplace domain, their associated values in time domain are calculated by the numerical inversion of Laplace transform. The main feature of this proposed boundary element is that no meshes are needed along the boundary of holes, cracks, inclusions and interfaces whose boundary conditions are satisfied exactly. To show this special feature by comparison with the other numerical methods, several examples are solved for the linear isotropic viscoelastic materials under plane strain condition. The results show that the present BEM is really more efficient and accurate for the problems of viscoelastic solids containing interfaces, holes, cracks, and/or inclusions.     

An Interleaved AC–DC Converter Based on Current Tracking

In this paper, an interleaved AC-DC converter based on current tracking without any current sharing required is presented and applied to a two-phase flyback converter. This is realized using two critical-conduction-mode (CRM) pulsewidth-modulated chips, together with a field-programmable gate array technique. By doing so, not only are the total harmonic distortion and the power factor improved but the output power is also upgraded. In this paper, the circuit operation is described in detail, with some experimental results given to verify the proposed control scheme.     

A study of electron beam-induced conductivity in resists.

The charging of polymeric resist materials during electron beam irradiation leads to significant problems during imaging and lithography processes. Charging occurs because of charge deposition in the polymer and charge generation/trapping due to formation of electron-hole pairs in the dielectric. The presence of such charge also results in the phenomena of electron beam-induced conductivity (EBIC). Electron beam-induced conductivity data have been obtained for three commercial e-beam resists under a variety of dose rate and temperature conditions. From the observed values of induced conductivity under varying conditions significant information about the generation of electron-hole pair and the transport of charge in the resist can be obtained. Three electron beam resists, EBR900, ZEP7000, and PBS are examined by an external bias method. The difference in resist chemistry is considered to play the role in the initial state EBIC behaviors among three resists even though the way that it affects the behaviors is not clear. A comparison of the power consumption comparison is proposed as a measure to give a preliminary estimate of the carrier concentration and carrier drift velocity differences among the resists. A simple single trap model with constant activation energy is proposed and provides good agreement with experiment.     

Interface corners in piezoelectric materials

Through proper arrangement, the constitutive law, strain-displacement relation and equilibrium equation of piezoelectric materials can be written in the same mathematical form as those of elastic materials and hence Stroh formalism can be extended for piezoelectric analysis. Based on this viewpoint, the authors’ previous works for fracture analysis of anisotropic elastic materials, e.g. the eigen-relation for determining singular orders, the near-tip solutions, and the unified definition of stress intensity factors for interface corners, can also be applied to piezoelectric materials. In this paper, the theoretical framework of our previous works is briefly introduced, and then an efficient and accurate computing method (H-integral) and its required auxiliary solutions are derived for extracting the stress/electric intensity factors of interface corners made up of piezoelectric materials. This theoretical framework and H-integral form a universal solution technique that is valid for the fracture analysis of cracks, corners, interface cracks, and interface corners. Besides, the special cases that suggest how we simulate elastic insulators/conductors from piezoelectric materials are discussed. Several numerical examples are dealt with to display the feasibility and applicability of the proposed approaches, and finally, a numerical example which exhibits how the electric load influences the fracture behavior is also studied.     

Curing of unsaturated polyester resins—effects of pressure

The effects of pressure ranging from 0.1 to 6.21 MPa (0–900 psig) on the curing of unsaturated polyester resins at 110°c were investigated by an approach of integrated reaction kinetics-rheology-morphology measurements using a pressure differential scanning calorimeter (DSC), an infrared spectrophotometer (IR), a Haake rheometer, and by using scanning electron microscopy (SEM). Increasing pressure was found to delay the gel effect, and a previously unknown plateau of kinetic-controlled region in the initial portion of the DSC rate profile was observed. The plateau region was mainly attributed to the crosslinking of C ? C double bonds inside the microgel particles, as revealed by the conversions of styrene and polyester C ? C bonds measured by IR, gel conversion data and SEM micrographs. The mechanisms of reaction kinetics both at atmospheric pressure and under pressures have also been elucidated by the progress of buildup of microgel structures.