Human stem cells and articular cartilage regeneration.

The regeneration of articular cartilage damaged due to trauma and posttraumatic osteoarthritis is an unmet medical need. Current approaches to regeneration and tissue engineering of articular cartilage include the use of chondrocytes, stem cells, scaffolds and signals, including morphogens and growth factors. Stem cells, as a source of cells for articular cartilage regeneration, are a critical factor for articular cartilage regeneration. This is because articular cartilage tissue has a low cell turnover and does not heal spontaneously. Adult stem cells have been isolated from various tissues, such as bone marrow, adipose, synovial tissue, muscle and periosteum. Signals of the transforming growth factor beta superfamily play critical roles in chondrogenesis. However, adult stem cells derived from various tissues tend to differ in their chondrogenic potential. Pluripotent stem cells have unlimited proliferative capacity compared to adult stem cells. Chondrogenesis from embryonic stem (ES) cells has been studied for more than a decade. However, establishment of ES cells requires embryos and leads to ethical issues for clinical applications. Induced pluripotent stem (iPS) cells are generated by cellular reprogramming of adult cells by transcription factors. Although iPS cells have chondrogenic potential, optimization, generation and differentiation toward articular chondrocytes are currently under intense investigation

Extracting Semantic Orientations of Words using Spin Model

We propose a method for extracting semantic orientations of words: desirable or undesirable. Regarding semantic orientations as spins of electrons, we use the mean field approximation to compute the approximate probability function of the system instead of the intractable actual probability function. We also propose a criterion for parameter selection on the basis of magnetization. Given only a small number of seed words, the proposed method extracts semantic orientations with high accuracy in the experiments on English lexicon. The result is comparable to the best value ever reported.

Fundamental Analysis of an Electrohydraulic Servomechanism Operated by PWM Mode

When an electrohydraulic servomechanism is used as a high performance servo, the PWM mode is interesting for the reduction of required accuracy in manufacturing valves and for removing the effects such as frictions of various parts. The manufactured servomechanism is composed of a torquemotor, a flapper-nozzle, a spool valve and an actuator. The input current to the torquemotor is in the form of a pulse-width-modulated wave supplied by a multivibrator, and the displacements of the flapper and the spool are restricted by the stoppers. The forces acting on the flapper caused by jets from nozzles are analyzed, and it is shown that the forces become as small as negligible, and sometimes accelerate the the flapper movement with a proper choice of discharge coefficient of nozzle. This means that the flapper-nozzle is favorable for a preamplifier in the PWM mode operation. As the results of the analysis, the displacement of the spool is approximately in the form of a trapezoidal pulse with certain time lag for the input to the torquemotor. When the load of the actuator consists of a mass and friction, the dither amplitude of the actuator piston is obtained exactly for the trapezoidal pulse input. The pulse period is determined by the waveshape of the spool displacement and the dither amplitude of the actuator piston. The analytical results were verified by experiments

Frequency Characteristics of PWM Mode Electrohydraulic Servos

In this paper, the frequency characteristics of the PWM mode electrohydraulic servo are analyzed. A two-stage electrohydraulic servo was manufactured for experiments. A multivibrator was used for generating a rectangular pulse train and it was modified to obtain a high modulation gain of the pulse width. A spool in the servo valve moves in the waveshape of a trapezoidal pulse train. From the analysis of the spool movement, the equivalent transfer function of the PWM mode was obtained, and the frequency characteristics of the servo loop was analyzed. The various problems accompanying the PWM operation are also shown. The analytical results were verified by experiments

エンドセリンによる気管平滑筋収縮の機構に関する研究 : エンドセリンET[A]、ET[B]受容体を介した細胞内情報伝達機構の解析

関西学院大

Development of Pancreatic Ductal Adenocarcinoma Associated with Intraductal Papillary Mucinous Neoplasia

We retrospectively investigated the incidence of pancreatic ductal adenocarcinoma among patients with intraductal papillary mucinous neoplasms of the pancreas. Based on imaging in 195 such patients, we chose surgery as initial treatment for 54, and periodic evaluation over 6 to 192 months (mean, 52) for 141. In 6 of the 141 patients observed for intraductal papillary mucinous neoplasm (4.2%), pancreatic ductal adenocarcinoma developed. Further, careful monitoring for cancer occurrence in the remnant pancreas proved essential in the surgical resection group; 2 of 26 patients (7.7%) subsequently developed pancreatic ductal adenocarcinoma in the remnant pancreas, at 41 months and 137 months after surgery. Serial observation of patients with intraductal papillary mucinous neoplasms by contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography therefore is critical, whether or not surgical treatment initially was performed

Plastic deformation of polycrystals of Co

The plastic behaviour of Co3(Al, W) polycrystals with the L12 structure has been investigated in compression from 77 to 1273 K. The yield stress exhibits a rapid decrease at low temperatures (up to room temperature) followed by a plateau (up to 950 K), then it increases anomalously with temperature in a narrow temperature range between 950 and 1100 K, followed again by a rapid decrease at high temperatures. Slip is observed to occur exclusively on {111} planes at all temperatures investigated. The rapid decrease in yield stress observed at low temperatures is ascribed to a thermal component of solid-solution hardening that occurs during the motion of APB-coupled dislocations whose core adopts a planar, glissile structure. The anomalous increase in yield stress is consistent with the thermally activated cross-slip of APB-coupled dislocations from (111) to (010), as for many other L12 compounds. Similarities and differences in the deformation behaviour and operating mechanisms among Co3(Al, W) and other L12 compounds, such as Ni3Al and Co3Ti, are discussed