Applicability of machine learning to a crack model in concrete bridges

The growing demand for a more efficient maintenance of concrete bridges requires a model that tracks the deterioration of each bridge based on inspection data. Although it has been expected that machine learning could be applied to this problem, inspection data sparsely distributed over time are not suitable for machine learning in contrast to the continuous big data usually targeted. This study applies machine learning to a regression model of crack formation and propagation using inspection data to confirm the applicability. It includes the selection of the optimal algorithm, development of the model based on a novel methodology, and factor analysis using the model. Accordingly, the model was constructed by Gaussian process regression and it could appropriately extract the differences in the progress of crack damage due to multiple influential factors. The results demonstrate the excellent applicability of machine learning even to sparse data.     

Molecular dynamics investigation of the fracture mechanism of a glass-ceramic containing cleavable crystals

In this study on a novel glass-ceramic containing hexagonal CaAl₂Si₂O₈ crystals embedded in a SiO₂–Al₂O₃–CaO glass, we used molecular dynamics simulations to unravel the toughening mechanism of the partially crystallized composite material. The crystalline phase is composed of alternate layers of SiO₄/AlO₄ tetrahedra and calcium ions. After careful modeling of crystals embedded in the glass matrix, we conducted crack propagation simulations using single-notched models. We found that: (a) when a crack propagates parallel to the cleavable calcium layer, the glass-ceramic breaks in a brittle way since the crack passes through the fragile interlayer promptly, (b) the stiffer SiO₄/AlO₄ oxide layer can inhibit crack propagation, and the crack is thus deflected to the interface between the crystal and the glass matrix; and (c) a calcium layer present between the glass matrix and the edge of the CaAl₂Si₂O₈ crystal is more fragile than those inside the crystal, indicating that cracks prefer to travel along the glass-crystal interface. These theoretical simulations successfully demonstrated that the anisotropy and the fragile feature of the crystals lead to microcrack toughening of the glass-ceramic. In addition, we discuss deformation anisotropy in the microscale by constructing a larger model that includes randomly orientated multiple CaAl₂Si₂O₈ crystals.     

Immunoglobulin-secreting cells in primary immunodeficiency diseases

To assess immunoglobulin production in vivo, the numbers of immunoglobulin-secreting cells were measured in uncultured peripheral blood mononuclear cells (PBMCs) of patients with primary immunoglobulin deficiency. The numbers of immunoglobulin-secreting cells were found to be variable, and they were well correlated with the serum concentrations of all three major immunoglobulin classes. Our results suggest that measurement of immunoglobulin-secreting cells in PBMCs is useful in the assessment of the ability to produce immunoglobulin in vivo.     

Self-Irradiation Damage of a Curium-Doped Titanate Ceramic Containing Sodium-Rich High-Level Nuclear Waste

The polyphase titanate ceramic containing sodium-rich simulated high-level nuclear waste was doped with 0.69 wt% of ²⁴⁴Cm to accelerate long-term self-irradiation due to α decays. α autoradiography showed that α emissions were almost uniformaly distributed throughout the curium-doped samples on a >20-μm scale although micropore surfaces and titanium oxide agglomerates were free of α-emitting nuclides. The phase assemblage of the curium-doped titanate ceramic included freudenbergite and loveringite in addition to the more abundant oxide phases: hollandite, perovskite, and zirconolite. Accumulation of α decays was accompanied by a gradual decrease in density. The increment of density was – 1% after an equivalent age of 5000 yr. Leach tests showed a slight trend toward higher total release of curium with equivalent age. The release of soluble nonradioactive elements (e.g., Na, Cs, Sr, and Ca) in the oldest specimens (equivalent age, 2000 yr) varied from specimen to specimen but, on average, were higher than specimens that had suffered a lower radiation dose.     

Early experience of minimally invasive valve surgery

Gene therapy has been proposed for a wide variety of human conditions including monogenic disorders, such as the haemoglobinopathies and immunodeficiency syndromes, cancer and many other diseases. Prerequisites for the success of this approach include the ability to deliver the therapeutic gene intact to the target cell, persistent levels of transgene expression sufficient to correct the disease phenotype, lack of unwanted side-effects associated with vector exposure or gene transfer and relative simplicity allowing the widespread use of this methodology. Although substantial progress has been made in animal models since the inception of genetic therapy in the early 1980s, significant obstacles remain for human therapy, most notably in the area of vector development. The first generation of gene therapy vectors has failed to overcome many of the biological hurdles cited above necessitating the development of alternate means of gene delivery and expression.     

Biochemical and immunochemical study of seven families with 3-ketothiolase deficiency: diagnosis of heterozygotes using immunochemical determination of the ratio of mitochondrial acetoacetyl-CoA thiolase and 3-ketoacyl-CoA thiolase proteins

The possibility of identifying heterozygotes of 3-ketothiolase deficiency, an inborn error of metabolism caused by a defect of mitochondrial acetoacetyl-CoA thiolase (T2), was tested in seven unrelated families by using enzymatic assay of thiolase activity and immunoblot analysis. The ratio of acetoacetyl-CoA thiolase activities, in the presence and absence of K+ ion (+K/-K ratio), in fibroblasts from 15 normal controls was around 2.0 (1.8 to 2.4), whereas the +K/-K ratio in eight patients was always 1.0. The ratio for the 13 obligate carriers ranged from 1.4 to 1.9, causing a minor overlap with control. Identification of heterozygote cells by immunoblot analysis, using anti-T2 antibody alone as a probe, was difficult, as previously reported. We therefore carried out immunoblot analysis, using as probes a mixture of anti-T2 antibody and the antibody against mitochondrial 3-ketoacyl-CoA thiolase (T1), another mitochondrial thiolase, and determined the ratio of the intensities of the T2 and T1 bands (T2/T1 ratio) using a densitometer. When the T2/T1 ratio was calculated, there was no overlap between the heterozygotes and normal controls. Hence, the heterozygotes can be unambiguously identified using this method. The thiolase activities and T2/T1 proteins in immunoblotting were detectable in peripheral lymphocytes, rectal mucosa, amniocytes, and liver. Thus, the postnatal diagnosis of 3-ketothiolase deficiency can be readily made using lymphocytes or rectal mucosa. The applicability of these methods in amniocytes indicates that prenatal diagnosis of this disease should be possible.     

Fabrication of Bi2Sr2CaCu2Ox films on metal substrates by the chemical process using metal alkoxides

The formation behaviour of Bi₂Sr₂CaCu₂O_x from compounds prepared by hydrolysis of metal alkoxides was studied and Bi₂Sr₂CaCu₂O_x films on metal substrates were fabricated using a metal alkoxide solution. Bi₂Sr₂CaCu₂O_x was formed through intermediate phases such as Bi₂Sr₂Cu₁O_x, Bi₂CuO₄, SrCO₃, CaCO₃ and CuO. Bi₂CuO₄ was initially formed with SrCO₃, CaCO₃ and CuO, and then reacted with SrCO₃ to form Bi₂Sr₂Cu₁O_x. Bi₂Sr₂Cu₁O_x reacted with CaCO₃ and CuO to give Bi₂Sr₂CaCu₂O_x. Bi₂Sr₂CaCu₂O_x films were successfully fabricated on nickel substrates using the metal alkoxide solution at the nominal composition of BiSrCaCu=2223. Bi₂Sr₂CaCu₂O_x was precipitated on Ni substrates at firing temperature of 770 °C or above, and a sharp T _c was obtained at the firing temperature of 800 °C.     

Protein Folding in the Presence of Water‐Soluble Cyclic Diselenides with Novel Oxidoreductase and Isomerase Activities

The protein disulfide isomerase (PDI) family, found in the endoplasmic reticulum (ER) of the eukaryotic cell, catalyzes the formation and cleavage of disulfide bonds and thereby helps in protein folding. A decrease in PDI activity under ER stress conditions leads to protein misfolding, which is responsible for the progression of various human diseases, such as Alzheimer's, Parkinson's, diabetes mellitus, and atherosclerosis. Here we report that water‐soluble cyclic diselenides mimic the multifunctional activity of the PDI family by facilitating oxidative folding, disulfide formation/reduction, and repair of the scrambled disulfide bonds in misfolded proteins.     

Finite element analysis of fracture statistics of ceramics: Effects of grain size and pore size distributions

A novel numerical simulation method based on finite element analysis (FEA), which can evaluate the fracture probability caused by the characteristics of flaw distribution, is considered an effective tool to facilitate and increase the use of ceramics in components and members. In this study, we propose an FEA methodology to predict the scatter of ceramic strength. Specifically, the data on the microstructure distribution (i.e., relative density, size and aspect ratio of pore, and grain size) are taken as the input values and reflected onto the parameters of a continuum damage model via a fracture mechanical model based on the circumferential circular crack emanating from an oval spherical pore. In addition, we numerically create a Weibull distribution based on multiple FEA results of a three‐point bending test. Its validity is confirmed by a quantitative comparison with the actual test results. The results suggest that the proposed FEA methodology can be applied to the analysis of the fracture probability of ceramics.     

Usefulness of myeloperoxidase as a biomarker for the ranking of pulmonary toxicity of nanomaterials

Background

In order to examine whether myeloperoxidase (MPO) can be a useful marker for evaluating the pulmonary toxicity of nanomaterials, we analyzed MPO protein in bronchoalveolar lavage fluid (BALF) samples obtained from previous examinations of a rat model. In those examinations we performed intratracheal instillation exposures (dose: 0.2–1.0 mg) and inhalation exposures (exposure concentration: 0.32–10.4 mg/m³) using 9 and 4 nanomaterials with different toxicities, respectively. Based on those previous studies, we set Nickel oxide nanoparticles (NiO), cerium dioxide nanoparticles (CeO₂), multi wall carbon nanotubes with short or long length (MWCNT (S) and MWCNT (L)), and single wall carbon nanotube (SWCNT) as chemicals with high toxicity; and titanium dioxide nanoparticles (TiO₂ (P90) and TiO₂ (Rutile)), zinc oxide nanoparticles (ZnO), and toner with external additives including nanoparticles as chemicals with low toxicity. We measured the concentration of MPO in BALF samples from rats from 3 days to 6 months following a single intratracheal instillation, and from 3 days to 3 months after the end of inhalation exposure.

Results

Intratracheal instillation of high toxicity NiO, CeO_2, MWCNT (S), MWCNT (L), and SWCNT persistently increased the concentration of MPO, and inhalation of NiO and CeO₂ increased the MPO in BALF. By contrast, intratracheal instillation of low toxicity TiO₂ (P90), TiO₂ (Rutile), ZnO, and toner increased the concentration of MPO in BALF only transiently, and inhalation of TiO₂ (Rutile) and ZnO induced almost no increase of the MPO. The concentration of MPO correlated with the number of total cells and neutrophils, the concentration of chemokines for neutrophils (cytokine-induced neutrophil chemoattractant (CINC)-1 and heme oxygenase (HO)-1), and the activity of released lactate dehydrogenase (LDH) in BALF. The results from the receiver operating characteristics (ROC) for the toxicity of chemicals by the concentration of MPO proteins in the intratracheal instillation and inhalation exposures showed that the largest areas under the curves (AUC) s in both examinations occurred at 1 month after exposure.

Conclusion

These data suggest that MPO can be a useful biomarker for the ranking of the pulmonary toxicity of nanomaterials, especially at 1 month after exposure, in both intratracheal instillation and inhalation exposure.