Optical on-line running reconstruction of MR-images in the phase-scrambling Fourier-imaging technique

Recently, the use of magnetic-resonance-guided navigation to improve the safety and effectiveness of surgical procedures has shown great promise. The purpose of the present study was to develop and demonstrate an imaging strategy that allows surgeons to continue operating without delays caused by imaging. The phase-scrambling Fourier-imaging technique has two prominent characteristics: localized image reconstruction and holographic image reconstruction. The combination of these characteristics allows images to be observed even during the data-acquisition period, because the acquired signal is converted into a hologram and the image is reconstructed instantly in the coherent optical image-processing system. Experimental studies have shown that the phase-scrambling Fourier-imaging technique enables the motion of objects to be imaged more quickly than the standard fast imaging. The proposed running reconstruction strategy can be easily implemented in the well-established magnetic-resonance imaging equipment that is currently in use.     

Color‐conversion method for a multi‐primary display to reduce power consumption and conversion time

Abstract— A color‐conversion method for a light‐emitting multi‐primary‐color display is proposed. While amulti‐primary‐color display uses four or more primary colors to reproduce a wide color gamut, multiple sets of primary‐color signals are needed to reproduce one color. Therefore, linear programming, which results in low power consumption, was adopted to uniquely determine the set of primary‐color signals. Although a highly accurate color conversion was achieved by using linear programming with low power consumption, it requires a very long time to convert colors of high‐resolution images. Therefore, by categorizing the color conversion of linear programming as a classification problem, colors are converted by using the decision‐tree method, which is a classification method. As a result, color conversion with high accuracy, low power consumption, and short conversion time was achieved.     

Expression of CD44 variant 6 and lymphatic invasion: importance to lymph node metastasis in gastric cancer

Lymph node metastasis is a critical prognostic factor for gastric cancer. In the present investigation we examined clinicopathologic factors influencing the metastatic processes to the lymph mode and their prognostic importance. A randomly selected group of 98 patients with adenocarcinomas of the stomach who underwent gastrectomy plus systematic lymph node dissection at Osaka Police Hospital from 1991 to 1996 were analyzed. Altogether 37 (38%) cancers were positive for CD44 variant 6 (v6) staining, 31 (32%) were intermediately stained, and 30 (30%) were negative. CD44-v6 expression correlated well with lymph node metastasis. Expression of CD44-v6 and lymphatic invasion were independent risk factors for metastatic lymph nodes. Among the patients with CD44-v6-positive and lymphatic invasion-positive cancers, 88% had lymph node metastasis, whereas only 13% of patients negative for both factors had lymph node metastasis. Although CD44-v6 expression and lymphatic invasion have been reported to be risk factors for recurrence and a poor prognosis, in this investigation these factors were found not to be significant for hematogenous and lymphatic recurrences or overall survival rates. Thus expression of CD44-v6 and lymphatic invasion may regulate lymph node metastases from gastric cancer.     

Change in fine structure of nylon 6 gut yarn in twisting,annealing, and untwisting processes. I. Observation by WAXD,SAXD, and EM

To obtain information on the change in fine structure of nylon 6 taking place during practical false-twisting processes, the manner of change in the three elemental processes, i.e., twisting, annealing, and untwisting, was studied. For simplicity, nylon 6 gut yarn was used instead of multifilament yarn. Wide- and small-angle x-ray diffraction (WAXD and SAXD) together with electron microscopy (EM) were used here. The degree of molecular orientation in the crystalline region of the twisted yarn gradually decreases with increase of the twist number (TN) in the region of TN ? 100. The long spacing, determined by SAXD, of the twisted yarn increases with increases in TN. The increase in long spacing cannot be interpreted only by macroscopic strain or elongation of the yarn in the twisting process. This difference seems to arise from the contribution of the decrease of lateral size of lamellae to the average long spacing; therefore the increase in long spacing should be attributed to the elongation of the amorphous region, deduced from the crystallinity measured by WAXD and the long spacing diffraction. The angle between the streak line on the surface of twisted yarn observed by EM and the fiber axis agrees well with the twist angle of the yarn. The crystal lamellae are stacked normal to the streak line at the initial stage, i.e., at a low value of TN, but they begin to deviate from the normal direction with increase in TN, accompanied by their partial destruction. Based on SAXD and density measurements, the internal strain of yarn annealed after twisting is fully relaxed. When the yarn is untwisted after twisting and annealing, the crystal orientation recovers gradually to that of the untreated yarn. The chain axis within the lamellae in the center region of the yarn becomes nearly parallel to the fiber axis, but the chain axis in the outer region does not.     

Application of focused ion beam techniques and transmission electron microscopy to thin-film transistor failure analysis

The locations of process-induced defects in hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs), which are used as elements of active-matrix liquid crystal displays, were investigated by combining focused ion beam techniques with cross-sectional transmission electron microscopy (X-TEM). The FIB technique is applied to TFT failure analysis problems, which require considerable localised etching without inducing mechanical stress or damage at fragile failure locations. We demonstrate the manner in which these techniques are used to characterise TFT defects such as pinholes and portions of the multilayer damaged by mechanical stress. A dramatic improvement brought about by the FIB technique is the increase in temporal efficiency of sample preparations. X-TEM observations also lead to identification of the fault and analysis of its cause, which in turn lead to a marked yield improvement.     

The relationship between electropermeabilization and cell cycle and cell size of Saccharomyces cerevisiae

Yeast cells (Sacchromyces cerevisiae) in 0.9% NaCl solution containing phloxine B (dye) were treated by an application of a rectangular electric pulse. We input microscopic images of the yeast suspensions after the application into a computer, and measured whether each cell dyes or not, the phase in the cell cycle, and each cell size, using the software we had developed. After those measurements, we discussed the relationship between the yield of electropermeabilization (the ratio of dyed cells to the total cell number) and the phase in the cell cycle, and cell size. From the results, it was found that the yeast cells from S-phase to M-phase (S-M phase) in the cell cycle tend to be more permeated than G1-phase yeast cells, and in both phases the yield decreases with the increase in cell size.     

Strong induction of phytochelatin synthesis by zinc in marine green alga, Dunaliella tertiolecta

Synthesis of phytochelatins (PCs), heavy-metal-sequestering peptides, in the marine green alga, Dunaliella tertiolecta, was evaluated under various conditions of exposure to heavy metals. To investigate the effect of heavy metals on both PC synthesis and their upstream biosynthetic reactions, an ion-pair-HPLC system was developed in this study, by which PCs and their biosynthetic intermediates, cysteine (Cys), gamma-glutamylcysteine (gammaEC) and glutathione (GSH), could be determined simultaneously with high sensitivity. When the cells were exposed to Zn2+, the level of PCs was maximal at 200 microM and significantly higher than that obtained after exposure to 400 microM Cd2+, which is the strongest inducer of PC synthesis in higher plants in vivo and in vitro as well as in microalgae. The predominant PC subtype was PC4, followed by PC3 and PC5, whereas PC2, which is generally abundant in higher plants, has the lowest level among PC2 to PC5. These results suggest that the characteristics of PC synthase in D. tertiolecta including the requirement of heavy metals for its catalysis and substrate specificity towards GSH and PC(n) are considerably different from those in higher plants and other algae. While PC synthesis proceeded in the heavy-metal-treated cells, the level of GSH did not appreciably change. To maintain the same size of the GSH pool, GSH must be newly synthesized to balance the amount consumed for PC synthesis.     

电动汽车稳定性控制中的车体侧偏角观测器研究

采用轮毂电机独立驱动的电动汽车可采用直接横摆力矩控制(Direct Yaw-moment Control,DYC)等稳定性控制,而车体侧偏角(简称β角)是稳定性控制中的重要参数.直接测定车体侧偏角的传感器相当昂贵,所以需要从能够容易测得的参数来进行车体侧偏角的推测.Hori研究室设计了一种用于β角推测的观测器,并充分考虑了车辆运行工况变化所引起的系统模型参数变化,进行了观测器鲁棒性设计以及轮胎侧偏刚度在线辨识,使观测器具备了足够的鲁棒性来克服大的模型误差影响,试验结果证明了该观测器的有效性.     

On phenomenological failure criteria for composite bolted joint analysis

There has been a recent trend to use phenomenological strength models in combination with point stress or average stress failure criteria to form strength models for the analysis of composite bolted joints. Several papers published using these approaches have demonstrated practical reductions in the size of the empirical data base required to perform bolted joint analysis for specific materials and laminates. Since the inception of phenomenological failure models for bolted joints several refinements have been proposed, but the generality of the method is not clearly defined. This paper addresses the concepts underlying the formulation of these strength models, compares the capabilities of several commonly used failure criteria and discusses the limits of applicability through example analyses and comparison with experimental data. The results indicate that differences in predicted strengths for the models examined were insignificant. Failure mode predictions based on single point failure location information varied from model to model and differed significantly from experimentally observed failure modes for some geometries. The models cannot be applied with confidence for the analysis of a wide class of laminates and geometries without calibrating the model through empirical data.