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    Kenji Shimada

    A 35-year-old woman at eight weeks of gestation in her second pregnancy presented with generalized seizures. Magnetic resonance images revealed a small hemorrhagic infarction in the left frontal lobe, and magnetic resonance venography... more
    A 35-year-old woman at eight weeks of gestation in her second pregnancy presented with generalized seizures. Magnetic resonance images revealed a small hemorrhagic infarction in the left frontal lobe, and magnetic resonance venography indicated cerebral venous sinus thrombosis. After hospitalization, anticoagulant therapy was continued, and a low protein C level was confirmed, which was also confirmed in both her mother and her sister. Follow-up magnetic resonance venography performed on day 27 confirmed that the cerebral venous sinuses had undergone recanalization. After a completed gestation period, the patient gave birth to healthy girl uneventfully.
    Design and optimization of hull shapes for optimal hydrodynamic performance have been a major challenge for naval architectures. Deep learning bears the promise of comprehensive geometric representation and new design synthesis. In this... more
    Design and optimization of hull shapes for optimal hydrodynamic performance have been a major challenge for naval architectures. Deep learning bears the promise of comprehensive geometric representation and new design synthesis. In this work, we develop a deep neural network (DNN)-based approach to encode the hull designs to condensed representations, synthesize novel designs, and optimize the synthetic design based on the hydrodynamic performance. A variational autoencoder (VAE) with the hydro-predictor is developed to learn the representation through reconstructing the Laplacian parameterized hulls and encode the geometry-drag function simulated through computational fluid dynamics (CFD). Two data augmentation techniques, Perlin noise mapping and free-form deformation (FFD), are implemented to create the training set from a parent hull. The trained VAE is leveraged to efficiently optimize from massive synthetic hull vessels toward the optimal predicted drag performance. The selected geometries are further investigated and virtually screened under CFD simulations. Experiments show that our convolutional neural network (CNN) model accurately reconstructs the input vessels and predicts the corresponding drag coefficients. The proposed framework is demonstrated to synthesize realistic hull designs and optimize toward new hull designs with the drag coefficient decreased by 35% comparing to the parent design.
    Abstract Phosphotransacetylase (PTA) is immobilized on AF-Tresyl TOYOPEARL 650 gel and used on-line in a stainless-steel column (10 × 4 mm i.d.). CoA-SH liberated enzymatically from acetyl-CoA is reacted with Ellman's reagent... more
    Abstract Phosphotransacetylase (PTA) is immobilized on AF-Tresyl TOYOPEARL 650 gel and used on-line in a stainless-steel column (10 × 4 mm i.d.). CoA-SH liberated enzymatically from acetyl-CoA is reacted with Ellman's reagent [5,5′-dithiobis(2-nitrobenzoic acid)] in the carrier stream. The calibration graph for acetyl-CoA is linear from 4 × 10−6 to 4 × 10−4 M and the detection limits is 8 × 10−7 M. The immobilized enzyme can be employed for over 4 months without any significant decrease in activity. The enzyme retains its activity in methanol even though the initial rate of reaction is decreased.
    A method for the determination of dehydroepiandrosterone sulphate (DHEA-S) in biological samples is described. [7,7,16,16-2H4]-Dehydroepiandrosterone sulphate (2H4-DHEA-S) was synthesized and its applicability was examined as an internal... more
    A method for the determination of dehydroepiandrosterone sulphate (DHEA-S) in biological samples is described. [7,7,16,16-2H4]-Dehydroepiandrosterone sulphate (2H4-DHEA-S) was synthesized and its applicability was examined as an internal standard with liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS). Deuterium atoms in 2H4-DHEA-S molecules were not exchanged to hydrogen atoms during the extraction procedure from biological specimens in the determination of DHEA-S with LC/MS. The calibration curve of DHEA-S was linear over the range of 2-500 ng on-column. The detection limit of DHEA-S was 0.5 ng on-column with a signal-to-noise ratio of 3. The relative standard deviations of intra- and inter-assay with 200 ng of standard sample were 3.3 and 5.0%, respectively. These results were better than a similar method reported on previously (Nakajima et al., 1996). The proposed method was successfully developed for the determination of DHEA-S in biological samples.
    Sexual differentiation of the external genitalia depends on many factors such as genetic sex, gonadal sex or androgen action. Among them, 5 alpha-reductase plays an important role in androgen action: dihydrotestosterone(DHT) is produce... more
    Sexual differentiation of the external genitalia depends on many factors such as genetic sex, gonadal sex or androgen action. Among them, 5 alpha-reductase plays an important role in androgen action: dihydrotestosterone(DHT) is produce from testosterone by 5 alpha-reductase and DHT binds the androgen receptor to induce the differentiation of the external genitalia. In this paper we reviewed on the mechanism of the differentiation of the external genitalia, especially on the relation with androgen action and 5 alpha-reductase.
    A male neonate was referred to our institute after the placement of right nephrostomy because he presented syndrome of acute renal failure and bilateral hydronephrosis. Voiding cystourethrography revealed bilateral vesicoureteral reflux... more
    A male neonate was referred to our institute after the placement of right nephrostomy because he presented syndrome of acute renal failure and bilateral hydronephrosis. Voiding cystourethrography revealed bilateral vesicoureteral reflux (right.; grade I, left.; grade V), and renal scintigraphy revealed left hypodysplastic kidney. Endoscopy revealed bilateral ectopic ureters; posterior urethra on the right and bladder neck on the left. We performed bilateral ureterocystoneostomy with bilateral ureteral folding. Postoperative course was uneventful, and the serum creatinine improved to the level of 0.5 mg/dl 6 months after the intervention.
    An 8-year-old boy was admitted because of left flank pain. The excretory urogram showed left hydronephrosis and a filling defect at the pelviureteric junction. Surgical exploration revealed a polypoid lesion on the mucous membrane of the... more
    An 8-year-old boy was admitted because of left flank pain. The excretory urogram showed left hydronephrosis and a filling defect at the pelviureteric junction. Surgical exploration revealed a polypoid lesion on the mucous membrane of the pelviureteric junction and ureteric stenosis due to a periureteric fibrous band. Dis-membered pyeloplasty was performed. The pathological diagnosis was benign fibrous polyp of the ureter. Convalescence was uneventful and an intravenous pyelogram showed no evidence of recurrence one year after operation. We found 13 cases of ureteral polyps in children in the Japanese literature. The differences between ureteral polyps in childhood and those in adults are discussed.
    Three patients were referred to our clinic with the chief complaint of emptiness of the right scrotal contents. Every physical examination in these patients revealed a little-finger-tip sized mass corresponding to the normal testis at the... more
    Three patients were referred to our clinic with the chief complaint of emptiness of the right scrotal contents. Every physical examination in these patients revealed a little-finger-tip sized mass corresponding to the normal testis at the right side of the femoral region. Right orchiopexy by the dartos-pouch technique was successfully performed. On every surgical exploration of these patients, the gubernaculum was fixed to the femoral skin and the testis was found to be normal in size. Our cases are the 2nd, 3rd and 4th cases of femoral testis, reported in the Japanese literature.
    A case of intracranial infectious granuloma extending into subcutaneous and subdural space mimicking malignant bone tumor was reported. A 49-year-old male was admitted to our service with complaint of left frontal subcutaneous and bone... more
    A case of intracranial infectious granuloma extending into subcutaneous and subdural space mimicking malignant bone tumor was reported. A 49-year-old male was admitted to our service with complaint of left frontal subcutaneous and bone tumor. Neurological examination demonstrated mild disorientation only except for pre-existeng Schizophrenia. CT scan and Gadolinium-enhanced MRI revealed left frontal intraosseous and subdural mass accompanied with remarkable edema. Left frontal bone was destructed by this mass. However, inflammatory sign nor malignant tumor could be observed and left frontal craniotomy and removal of the tumor was performed. The tumor was solid, elastic hard and existing from intra-osseous, epidural and subdural space compressing the cortex. No abscesss cavity could be found. Histological examination revealed infectious granuloma accompanied by remarkable neutrophil infiltration only. The patient showed good post-operative course, and returned to previous condition, pre-existeng Schizophrenia only. Intracranial infectious granuloma extending into subcutaneous and subdural space destructing the bone was rare condition. From literature, similar cases could be found in granuloma arising from osteomyelitis. In this case, destructed bone beneath the epi- and subdural tumor support this route of infection.
    A clinical study was conducted on the intermittent hydronephrosis in children. Of 78 children with hydronephrosis due to ureteropelvic junction obstruction operated between 1991 and 1995, 5 had intermittent hydronephrosis. All 5 patients... more
    A clinical study was conducted on the intermittent hydronephrosis in children. Of 78 children with hydronephrosis due to ureteropelvic junction obstruction operated between 1991 and 1995, 5 had intermittent hydronephrosis. All 5 patients were boys between 6 months and 6 years of age. Presenting symptoms were intermittent flank pain and vomiting. Ultrasonography performed during pain attack demonstrated dilation of the renal pelvis in all patients. Diuretic renography demonstrated obstruction in 4 of the 5 children and deterioration of renal function on the affected side in 2. The cause of ureteropelvic junction obstruction was aberrant vessels in 2 cases, fibrous band in 1, ureteral kinking within adventitia in 1 and a ureteral polyp in 1. Postoperatively, all patients have been relieved from the pain. In summary, ultrasonography at the time of symptom attack as well as diuretic renography are useful for the diagnosis and observation of intermittent hydronephrosis.
    <jats:title>Abstract</jats:title> <jats:p>This paper presents a new computational method for quadrilateral meshing of a thin, or narrow, two-dimensional domain. An output mesh of our method is well-shaped and either... more
    <jats:title>Abstract</jats:title> <jats:p>This paper presents a new computational method for quadrilateral meshing of a thin, or narrow, two-dimensional domain. An output mesh of our method is well-shaped and either single-layered, multi-layered, or partially multi-layered. Element sizes can be uniform or graded. A high quality, layered quadrilateral mesh is often required for finite element analyses of a narrow two-dimensional domain with a large deformation such as the analysis of rubber deformation or sheet metal forming. Our method consists of two steps: (1) extraction of the skeleton of a given domain by the discrete chordal axis transformation, and (2) discretization of the chordal axis into a set of line segments and conversion of each of the line segments to a single quadrilateral element or multiple layers of quadrilateral elements. In both steps we use a physically-based computational method called bubble packing to discretize a curve into a set of line segments of specified sizes. Experiments show that the accuracy of a large-deformation FEM analysis can be significantly improved by using a well-shaped quadrilateral mesh created by the proposed method.</jats:p>
    Checkpoints are conserved mechanisms that prevent progression into the next phase of the cell cycle when cells are unable to accomplish the previous event properly. Cells also possess a surveillance mechanism called the DNA replication... more
    Checkpoints are conserved mechanisms that prevent progression into the next phase of the cell cycle when cells are unable to accomplish the previous event properly. Cells also possess a surveillance mechanism called the DNA replication checkpoint, which consists of a conserved kinase cascade that is provoked by insults that block or slow down replication fork progression. In the budding yeast Saccharomyces cerevisiae, the DNA replication checkpoint controls the timing of S-phase events such as origin firing and spindle elongation. This checkpoint also upregulates dNTP pools and maintains the replication fork structure in order to resume DNA replication after replication block. Many replication checkpoint factors have been found to be tumor suppressors, highlighting the importance of this checkpoint pathway in human health. Here we describe a series of protocols to analyze the DNA replication checkpoint in S. cerevisiae.

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