Space-Time Finite Element Method for Seismic Analysis of Concrete Dam

Finite element method (FEM) is the most extended approach for analyzing the design of the dams against earthquake motion. In such simulations, time integration schemes are employed to obtain the response of the dam at time tn+1 from the known response at time tn. To this end, it is desirable that such schemes are high-order accurate in time and remain unconditionally stable large time-step size can be employed to decrease the computation cost. Moreover, such schemes should attenuate the high-frequency components from the response of structure being studied. Keeping this in view, this chapter presents the theory of time-discontinuous space-time finite element method (ST/FEM) and its application to obtain the response of dam-reservoir system to seismic loading

The perineuronal proteoglycan surface coat in the adult rat brain, with special reference to its reactions to Gomori's ammoniacal silver.

The present study showed that many neurons in the adult rat brain possessed a perineuronal sulfated proteoglycan surface coat which reacted to cationic iron colloid and aldehyde fuchsin. This surface coat was stained supravitally with Ehrlich's methylene blue and doubly stained with Ehrlich's methylene blue and aldehyde fuchsin. The surface coat was also stained with Gomori's ammoniacal silver and doubly stained with Gomori's ammoniacal silver and cationic iron colloid. The surface coat was usually expressed together with a nerve cell surface glycoprotein net detectable with lectin Wisteria floribunda agglutinin. These findings indicate that the perineuronal proteoglycan surface coat is identical to Cajal's superficial reticulum and contains some collagenous elements. It was further demonstrated that collagenase digestion erased Gomori's ammoniacal silver impregnation within the perineuronal proteoglycan surface coat.</p

Biliary reconstruction with right hepatic lobectomy due to delayed management of laparoscopic bile duct injuries: a case report.

We report a case requiring biliary reconstruction with right hepatic lobectomy due to biliary strictures caused by continuous cholangitis after laparoscopic bile duct injury. The patient, a 55-year-old woman, underwent laparoscopic cholecystectomy for cholelithiasis at another hospital. Although a bile leakage from the intraabdominal drain was observed several days after the operation, the patient was not given adequate treatment to stop the leakage. Two months after the initial laparoscopic cholecystectomy, she was referred to our hospital. Endoscopic retrograde cholangiopancreatography (ERCP) showed complete obstruction of the common hepatic duct, which was caused by clipping during laparoscopic cholecystectomy. Cholangiography from percutaneous transhepatic biliary drainage (PTBD) catheters revealed that sections of the secondary branches of the right intrahepatic bile duct had become constricted due to persistent cholangitis. Fortunately, the left hepatic duct was judged to be normal by imaging. Therefore, we elected to perform a right hepatic lobectomy and left hepaticojejunostomy, because we felt that performing a hepaticojejunostomy without hepatic resection would put the patient at risk of continuing to suffer from cholangitis. The patient was discharged on the 55 th postoperative day, and, 5 years after reconstructive surgery, is healthy and has remained free from biliary strictures in the remnant liver. Appropriate decision-making is essential in the treatment of biliary injury after laparoscopic cholecystectomy. Surgeons should not hesitate to perform biliary reconstruction with hepatic resection to reduce the risk of cholangitis or biliary strictures of the remnant liver. More importantly, preoperative clear imaging of the biliary tree and suitable management of any biliary injury which might occur are necessary to avoid having to perform reconstructive surgery.</p

Numerical Gradient Computation for Simultaneous Detection of Geometry and Spatial Random Fields in a Statistical Framework

The target of this chapter is the evaluation of gradients in inverse problems where spatial field parameters and geometry parameters are treated separately. Such an approach can be beneficial especially when the geometry needs to be detected accurately using L2-norm-based regularization. Emphasis is laid upon the computation of the gradients directly from the governing equations. Working in a statistical framework, the Karhunen-Loève (K-L) expansion is used for discretization of the spatial random field and inversion is done using the gradient-based Hamiltonian Monte Carlo (HMC) algorithm. The HMC gradients involve sensitivities w.r.t the random spatial field and geometry parameters. Building on a method developed by the authors, a procedure is developed which considers the gradients of the associated integral eigenvalue problem (IEVP) as well as the interaction between the gradients w.r.t random spatial field parameters and the gradients w.r.t the geometry parameters. The same mesh and linear shape functions are used in the finite element method employed to solve the forward problem, the artificial elastic deformation problem and the IEVP. Analysis of the rate of convergence using seven different meshes of increasing density indicates a linear rate of convergence of the gradients of the log posterior

Millimeter-Thick Single-Walled Carbon Nanotube Forests: Hidden Role of Catalyst Support

A parametric study of so-called "super growth" of single-walled carbon nanotubes(SWNTs) was done by using combinatorial libraries of iron/aluminum oxide catalysts. Millimeter-thick forests of nanotubes grew within 10 min, and those grown by using catalysts with a thin Fe layer (about 0.5 nm) were SWNTs. Although nanotube forests grew under a wide range of reaction conditions such as gas composition and temperature, the window for SWNT was narrow. Fe catalysts rapidly grew nanotubes only when supported on aluminum oxide. Aluminum oxide, which is a well-known catalyst in hydrocarbon reforming, plays an essential role in enhancing the nanotube growth rates.Comment: 11 pages, 3 figures. Jpn. J. Appl. Phys. (Express Letters) in pres

Image velocimetry for clouds with relaxation labeling based on deformation consistency

Correlation-based cloud tracking has been extensively used to measure atmospheric winds, but still difficulty remains. In this study, aiming at developing a cloud tracking system for Akatsuki, an artificial satellite orbiting Venus, a formulation is developed for improving the relaxation labeling technique to select appropriate peaks of cross-correlation surfaces which tend to have multiple peaks. The formulation makes an explicit use of consistency inherent in the type of cross-correlation method where template sub-images are slid without deformation; if the resultant motion vectors indicate a too-large deformation, it is contradictory to the assumption of the method. The deformation consistency is exploited further to develop two post processes; one clusters the motion vectors into groups within each of which the consistency is perfect, and the other extends the groups using the original candidate lists. These processes are useful to eliminate erroneous vectors, distinguish motion vectors at different altitudes, and detect phase velocities of waves in fluids such as atmospheric gravity waves. As a basis of the relaxation labeling and the post processes as well as uncertainty estimation, the necessity to find isolated (well-separated) peaks of cross-correlation surfaces is argued, and an algorithm to realize it is presented. All the methods are implemented, and their effectiveness is demonstrated with initial images obtained by the ultraviolet imager onboard Akatsuki. Since the deformation consistency regards the logical consistency inherent in template matching methods, it should have broad application beyond cloud tracking

Effects of adenoviral-mediated hepatocyte growth factor on liver regeneration after massive hepatectomy in rats

Resection is the only curative treatment for liver metastasis of colorectal cancers. Despite the supreme regenerative potential of the liver, major hepatectomy sometimes leads to liver failure, and the limitation of resectable liver volumes makes advanced tumors inoperable. This study was attempted to promote liver regeneration using hepatocyte growth factor (HGF) gene transfection by venous-administered adenovirus and to improve the survival of rats after massive hepatectomy. The adenovirus that encodes HGF was administered to rats before 85%-hepatectomy. The administration of HGF gene improved the survival of rats after massive hepatectomy, while the administration of control adenovirus deteriorated their survival. Gene transfection of HGF showed up-regulation of serum HGF, stimulation of hepatocellular proliferation and rapid liver regeneration. Moreover, HGF administration reduced apoptosis of hepatocytes. The administration of HGF gene prevented liver dysfunction after major hepatectomy and may be a new assist for surgery.</p

Basic analysis of optimal images for the development of 4D radiotherapy system

Understanding respiratory motion is necessary for accurate dose administration during stereotactic body radiation therapy. Although four-dimensional （4D） computed tomography （4DCT） is useful for understanding respiratory movements, 4D radiotherapy with a time axis is required. However, reports on the evaluation of 4DCT remain lacking. Therefore, this study was designed to evaluate the basic physical characteristics of a respiratory-gated 4DCT helical scanning system （4D-HS） using MATLABⓇ. In this study, the physical characteristics were evaluated by examining the body-axis direction resolution, slice sensitivity profile （SSP）, and volume change due to respiratory phase change and comparing multiplanar reconstruction profiles （MPRs） of slit phantoms. These characteristics were compared using normal helical scanning （N-HS）. A 31％ overestimation was observed in the volume fluctuation of 4D-HS based on the volume of N-HS. Furthermore, SSP with full width at half maximum （FWHM） and modulation transfer function （MTF） showed a similar resolution between 4D-HS and N-HS. The difference in FWHM is considered an offset by the voxel effect. In the MPR comparison, both 4D-HS and N-HS were visually identifiable up to a 0.5-mm slit. 4D-HS is a reconstruction system with excellent temporal resolution. Furthermore, its resolution follows respiratory dynamics and can continuously collect respiratory dynamics components. Our findings suggest the usefulness of 4D-HS in clinical practice

In Vitro Assessment of Factors Affecting the Apparent Diffusion Coefficient of Ramos Cells Using Bio-phantoms

The roles of cell density, extracellular space, intracellular factors, and apoptosis induced by the molecularly targeted drug rituximab on the apparent diffusion coefficient (ADC) values were investigated using bio-phantoms. In these bio-phantoms, Ramos cells (a human Burkittｾs lymphoma cell line) were encapsulated in gellan gum. The ADC values decreased linearly with the increase in cell density, and declined steeply when the extracellular space became less than 4 μm. The analysis of ADC values after destruction of the cellular membrane by sonication indicated that approximately 65% of the ADC values of normal cells originate from the cell structures made of membranes and that the remaining 35% originate from intracellular components. Microparticles, defined as particles smaller than the normal cells, increased in number after rituximab treatments, migrated to the extracellular space and significantly decreased the ADC values of bio-phantoms during apoptosis. An in vitro study using bio-phantoms was conducted to quantitatively clarify the roles of cellular factors and of extracellular space in determining the ADC values yielded by tumor cells and the mechanism by which apoptosis changes those values