Publications by authors named "Takuto Kojima"

Multicrystalline materials play a crucial role in our society. However, their microstructure is complicated, and there is no universal approach to achieving high performance. Therefore, a methodology is necessary to answer the fundamental question of how we should design and create microstructures.

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A comprehensive analysis of optical and photoluminescence images obtained from practical multicrystalline silicon wafers is conducted, utilizing various machine learning models for dislocation cluster region extraction, grain segmentation, and crystal orientation prediction. As a result, a realistic 3D model that includes the generation point of dislocation clusters is built. Finite element stress analysis on the 3D model coupled with crystal growth simulation reveals inhomogeneous and complex stress distribution and that dislocation clusters are frequently formed along the slip plane with the highest shear stress among twelve equivalents, concentrated along bending grain boundaries (GBs).

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Polarized optical microscopy (POM) images of polymer network liquid crystals (PNLCs) were first analyzed using a pretrained machine learning model for feature extraction and hierarchical clustering. The analyses worked well in predicting and improving the thermoresponsive changes individually in direct luminous and hemispheric solar transmittance, both of which are crucial properties of energy-saving smart windows. The features of a 1280 × 1920-pixel color POM image were extracted by the latest pretrained algorithm, EfficientNet-B7, as a 2560-dimensional vector and then reduced into a two-dimensional space for clustering and visualization using the uniform manifold approximation and projection (UMAP) algorithm while efficiently preserving the global structures of the distance relationship in a high-dimensional space.

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The beta-glucocerebrosidase (GBA1) gene encodes the lysosomal beta-glucocerebrosidase (GCase) that metabolizes the lipids glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph). Biallelic loss-of-function mutations in GBA1 such as L444P cause Gaucher disease (GD), which is the most prevalent lysosomal storage disease and is histopathologically characterized by abnormal accumulation of the GCase substrates GlcCer and GlcSph. GD with neurological symptoms is associated with severe mutations in the GBA1 gene, most of which cause impairment in the process of GCase trafficking to lysosomes.

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The casting mono-like silicon (Si) grown by directional solidification (DS) is promising for high-efficiency solar cells. However, high dislocation clusters around the top region are still the practical drawbacks, which limit its competitiveness to the monocrystalline Si. To optimize the DS-Si process, we applied the framework, which integrates the growing experiments, transient global simulations, artificial neuron network (ANN) training, and genetic algorithms (GAs).

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Background: The major symptoms of irritable bowel syndrome (IBS) are changes in bowel habits and abdominal pain. Psychological stress is the major pathophysiological components of IBS. Corticotropin-releasing factor (CRF) is a well-known integrator in response to psychological stress.

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Article Synopsis
  • GCN2 is a key regulator involved in how cancer cells cope with amino acid shortages in their environment, making it a potential target for new cancer treatments.
  • Researchers are focusing on creating innovative GCN2 inhibitors by modifying sulfonamide compounds, which could serve as first-in-class anti-cancer drugs.
  • One specific compound showed promising results by slowing its dissociation from GCN2, leading to anti-cancer effects when used with asparaginase in leukemia cells and mice, potentially inhibiting GCN2 activation.
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We pursued serine palmitoyltransferase (SPT) inhibitors as novel cancer therapeutic agents based on a correlation between SPT inhibition and growth suppression of cancer cells. High-throughput screening and medicinal chemistry efforts led to the identification of structurally diverse SPT inhibitors 4 and 5. Both compounds potently inhibited SPT enzyme and decreased intracellular ceramide content.

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A new class of corticotropin releasing factor 1 (CRF) receptor antagonists characterized by a tricyclic core ring was designed and synthesized. Novel tricyclic derivatives 2a-e were designed as CRF receptor antagonists based on conformation analysis of our original 2-anilinobenzimidazole CRF receptor antagonist. The synthesized tricyclic derivatives 2a-e showed CRF receptor binding activity with IC values of less than 400 nM, and the 1,2,3,4-tetrahydropyrimido-[1,2-a]benzimidazole derivative 2e was selected as a lead compound with potent in vitro CRF receptor binding activity (IC = 7.

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The aim of this study was to investigate peripheral and central roles of corticotropin-releasing factor (CRF) in endocrinological and behavioral changes. Plasma adrenocorticotropin (ACTH) concentration was measured as an activity of hypothalamic-pituitary-adrenal (HPA) axis. As behavioral changes, locomotion and anxiety behavior were measured after CRF challenge intravenously (i.

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Compound 1 exhibits potent binding inhibition activity against a corticotropin-releasing factor 1 (CRF) receptor (IC=9.5nM) and in vitro antagonistic activity (IC=88nM) but is rapidly metabolized by human hepatic microsomes (182μL/min/mg). Here we identified metabolically stable compounds with potent CRF binding inhibitory activity.

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Metabolic reprogramming is an essential hallmark of neoplasia. Therefore, targeting cancer metabolism, including lipid synthesis, has attracted much interest in recent years. Serine palmitoyltransferase (SPT) plays a key role in the initial and rate-limiting step of de novo sphingolipid biosynthesis, and inhibiting SPT activity prevents the proliferation of certain cancer cells.

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The present study evaluated whether slow-wave sleep and whole-night delta power of the non-rapid eye movement (NREM) sleep electroencephalogram (EEG) decrease during sleep at a simulated altitude of 2000 m, and whether such changes related to measures of hypoxic ventilatory response (HVR). This study consisted of two parts; in the first, HVR was measured in 41 subjects and each seven subjects with the lowest or the highest HVR were selected for the subsequent sleep study. In the second part, polysomnogram, arterial oxygen saturation (SpO2) and respiratory events are recorded on the selected subjects under normoxic and hypoxic conditions.

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Although crystalline silicon is widely used as substrate material for solar cell, many defects occur during crystal growth. In this study, the generation of crystalline defects in silicon substrates was evaluated. The distributions of small-angle grain boundaries were observed in substrates sliced parallel to the growth direction.

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Article Synopsis
  • A 74-year-old man presented with severe abdominal pain in April 2008 and was diagnosed with Stage IVa esophageal endocrine cell carcinoma, with cancer spread to nearby lymph nodes.
  • He underwent concurrent chemoradiotherapy, which significantly reduced the primary tumor, leading to a diagnosis of complete remission after two treatment courses.
  • Unfortunately, by June 2009, he experienced a relapse with liver metastasis, and despite starting second-line chemotherapy, his health deteriorated, resulting in his death on October 2, 2009.
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Background/aims: Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by diffuse mucosal inflammation, traditionally regarded as being limited to the colorectum. Although several gastroduodenal lesions have also been reported recently in cases of UC, in general, small-bowel lesions in UC are believed to be extremely rare. The aim of this study was to examine the small bowel by capsule endoscopy in patients with UC.

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