Nondestructive Integrated CT-XRD Method for Research on Hydrated Cement System

A nondestructive integrated CT-XRD method has been developed and used to study hydrated cement system. In this research, a beam line (BL) at the third-generation synchrotron radiation facility, SPring-8, in Japan, was used. First, X-ray computed tomography (CT) was employed to obtain three-dimensional (3D) images and select a region of interest (ROI) in a given plane section of the hardened cement paste. Then, X-ray diffraction analysis (XRD) was conducted on the specified region. These operations were implemented in situ without the removal of specimen from the stage inside the BL. The hardened cement paste was precracked and then leached by continuous water flow through the specimen, and the integrated CT-XRD method was conducted before and after the leaching test. In this way, the change in the hydrated cement system was characterized over time using the same specimen. CT observation provides the location of cracks and air voids as well as high and low density substances present in the hydrated cement system. ROI is arbitrarily determined at a set of coordinates at which one likes to evaluate the change in the cement system using XRD. This newly developed technique enables the evaluation of the presence of calcium hydroxide (portlandite) over time and space

Mutual information estimation reveals global associations between stimuli and biological processes

Background: Although gene expression analysis with microarray has become popular, it remains difficult to interpret the biological changes caused by stimuli or variation of conditions. Clustering of genes and associating each group with biolog-ical functions are often used methods. However, such methods only detect partial changes within cell processes. Herein, we propose a method for discovering global changes within a cell by associ-ating observed conditions of gene expression with gene functions. Results: To elucidate the association, we intro-duce a novel feature selection method called Least-Squares Mutual Information (LSMI), which com-putes the relation based on mutual information, and therefore LSMI can detect nonlinear associa-tions within a cell. We demonstrate the effective-ness of LSMI through comparison with existing methods. The results of the application to yeast microarray datasets reveal that non-natural stimuli affect various biological processes, whereas others are no significant relation to specific cell processes. Furthermore, we discover that biological processes can be categorized into four types according to the responses of various stimuli. They are those re-lated to DNA/RNA metabolic processes, gene ex-pression, protein metabolic processes, and protein localization. Conclusions: We proposed a novel feature selection method called LSMI, and applied LSMI to mining the association between conditions of yeast and bi-ological processes through microarray datasets. In fact, LSMI allows us to elucidate the global orga-nization of cellular process control

Flexural anisotropy of rift-sawn softwood boards induced by the end-grain orientation

Inspired by the use of rift-sawn softwood board for covering curved surfaces in Kokerabuki, a traditional Japanese roofing method, we investigated the flexural anisotropy of wood caused by its end-grain orientation. We measured the flexural displacement of softwood species, Chamaecyparis obtusa and Cryptomeria japonica, and hardwood species, Populus suaveolens and Cerasus serrulata. For the softwood species, this was approximately five times longer for the rift-sawn specimens than for the other grain patterns. Using the replica method to measure the softwood tracheid deformation with different flexural displacements, we confirmed the different deformation mechanisms of the tracheid in the flat- and quarter-sawn specimens, and rift-sawn specimens. In the flat- and quarter-sawn woods, on-axis loading was generated, in which the stress was concentrated on the radial and tangential cell walls parallel to the direction of tension or compression. By contrast, in the rift-sawn wood, off-axis loading was generated, in which the stress was evenly distributed throughout the corner cell walls without the wall directly resisting the tensile and compressive forces. We also concluded that the tapered shape of the tracheid walls contributes to the excellent flexibility of rift-sawn softwood

Mode-Seeking Clustering and Density Ridge Estimation via Direct Estimation of Density-Derivative-Ratios

Modes and ridges of the probability density function behind observed data are useful geometric features. Mode-seeking clustering assigns cluster labels by associating data samples with the nearest modes, and estimation of density ridges enables us to find lower-dimensional structures hidden in data. A key technical challenge both in mode-seeking clustering and density ridge estimation is accurate estimation of the ratios of the first- and second-order density derivatives to the density. A naive approach takes a three-step approach of first estimating the data density, then computing its derivatives, and finally taking their ratios. However, this three-step approach can be unreliable because a good density estimator does not necessarily mean a good density derivative estimator, and division by the estimated density could significantly magnify the estimation error. To cope with these problems, we propose a novel estimator for the density-derivative-ratios. The proposed estimator does not involve density estimation, but rather directly approximates the ratios of density derivatives of any order. Moreover, we establish a convergence rate of the proposed estimator. Based on the proposed estimator, novel methods both for mode-seeking clustering and density ridge estimation are developed, and the respective convergence rates to the mode and ridge of the underlying density are also established. Finally, we experimentally demonstrate that the developed methods significantly outperform existing methods, particularly for relatively high-dimensional data.Peer reviewe

Evaluation of Alteration in Cement Paste Due to Calcium Leaching withIntegrated CT-XRD Method and Its Effect on Ionic Diffusions

In 2011, Tohoku earthquake and subsequent tsunami hit Fukushima Daiichi Nuclear Power Plant, and they lead to Fukushima nuclear disaster. For more than a decade after the disaster, concrete materials in submerged structures of nuclear power plants have been chronically in contact with water and resulted in calcium leaching. To assess the alteration of the concrete property, it’s necessary to evaluate the permeability change due to calcium leaching and its effect on radioactive ion diffusion. In this study, small scale cylindrical cement paste specimens with 3mm in diameter and 6mm in height were prepared with water to cement ratios of 0.5 and 0.6 respectively, and they were tested in the static leaching. Specimens were subjected to carbonation before immersed into deionized water for different periods. CT image of each specimen at a resolution of 2.46μm/voxel was acquired in SPring-8, Hyogo, Japan. Combining CT images and X-ray diffraction data, dissolution front of portlandite under different leaching periods was determined, and the time dependent development law of dissolution front was evaluated. Introducing Buil’s model as a local equilibrium, time and position dependent porosity of cement paste due to leaching was calculated and correspondingly diffusion coefficient of Sr ion in the numerical simulation was modified. Simulative results on Sr ion diffusivity for 10-year showed the impact of carbonation followed by leaching on radioactive ion diffusion

Prevalence of anemia in patients with chronic kidney disease in Japan: A nationwide, cross-sectional cohort study using data from the Japan Chronic Kidney Disease Database (J-CKD-DB)

Background: The Japan Chronic Kidney Disease Database (J-CKD-DB) is a nationwide clinical database of patients with chronic kidney disease (CKD) based on electronic health records. The objective of this study was to assess the prevalence of anemia and the utilization rate of erythropoiesis-stimulating agents (ESAs) in Japanese patients with CKD. Methods: In total, 31, 082 adult outpatients with estimated glomerular filtration rates of 5–60 ml/min/1.73 m2 in seven university hospitals were included this analysis. The proportions of patients with CKD stages G3b, G4, and G5 were 23.5%, 7.6%, and 3.1%, respectively. Results: The mean (standard deviation) hemoglobin level of male patients was 13.6 (1.9) g/dl, which was significantly higher than the mean hemoglobin level of female patients (12.4 (1.6) g/dl). The mean (standard deviation) hemoglobin levels were 11.4 (2.1) g/dl in patients with CKD stage G4 and 11.2 (1.8) g/dl in patients with CKD stage G5. The prevalences of anemia were 40.1% in patients with CKD stage G4 and 60.3% in patients with CKD stage G5. Logistic regression analysis showed that diagnoses of CKD stage G3b (adjusted odds ratio [95% confidence interval]: 2.32 [2.09–2.58]), G4 (5.50 [4.80–6.31]), and G5 (9.75 [8.13–11.7]) were associated with increased prevalence of anemia. The utilization rates of ESAs were 7.9% in patients with CKD stage G4 and 22.4% in patients with CKD stage G5. Conclusions: We determined the prevalence of anemia and utilization rate of ESAs in Japanese patients with CKD using data from a nationwide cohort study