168 research outputs found

    Numerical Simulation of Flat-to-slant Ductile Fracture Transition in Notched Plate

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    AbstractThe effort of this study is to develop a damage model for simulating large ductile crack extension accompanied by a flat and a slant surface observed in the hydrostatic full-scale tests up to rupture for API X80 line pipes with an axial through-wall notch. A small and thin specimen with a shallow through-thickness notch having a large ligament (sub-sized Charpy V-notch (Sub-CVN) specimen subjected to 3-point bending) is used for a fundamental verification study. The Sub-CVN specimen provided the similar macroscopic process as well as micro-mechanism for ductile cracking, where a flat-to-slant fracture transition accompanied by a transition from an equi-axed dimple mode to a shear-slip mode fracture is presented. On the basis of the observed mechanism of ductile crack growth, a numerical ductile damage model for predicting the large ductile crack growth resistance is proposed taking into account an effect of the Lode parameter on ductile fracture into the present damage model proposed by authors. The crucial consideration is that the damage parameters to be identified can be correlated to the material properties. In this model, the shear-dominated stress state is assumed to advance the acceleration of damage evolution due to a shear localization mechanism at lower damage level even at the same stress triaxiality condition, so that the critical damage fraction dependent on the Lode parameter is phenomenologically employed in this model. The modified damage model reproduces the same ductile crack profile together with the same micro-mechanisms for forming the chevron-shaped flat surface as those observed in the experiment. The possibility to reproduce the flat-to-slant fracture transition is also demonstrated by the simulation

    Simplified Analysis of Toxic Gaseous Substance in Forensic Practice: Experiences from Japan

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    Toxicological examination in forensic practice is important for the proper diagnosis of acute poisoning. We have discussed the properties and features of poisoning incidents due to gaseous substances and elaborated on the simplified analytical techniques and apparatus used for their identification and quantitation for forensic purposes. Briefly, we have explained the simplified analysis of toxic gaseous substances such as carbon monoxide, hydrogen cyanide, hydrogen sulfide, and helium in blood. The techniques used include color testing, gas chromatography, detector tube, oximeter, and spectrophotometric method. In doing so, we have shared our experiences and highlighted the fact that the analysis of gaseous substances can be performed using readily available laboratory tools and equipment. We have emphasized the need and usefulness of the reference data tables for guiding forensic diagnosis. We hope that the above overview will assist other colleagues to implement such simplified techniques for the advancement of forensic medicine practice

    Application of CO-oximeter for Forensic Samples

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    CO-oximeter is routinely used in clinical practice, and it has been applied in the field of forensic medicine. It is a simultaneous and nondestructive technique for the analysis of total hemoglobin (Hb) and various Hb species, such as oxyhemoglobin, reduced hemoglobin, carboxyhemoglobin, and methemoglobin. It automatically measures the proportion of each species of Hb and oxygen contents. This is an easy, rapid, and convenient way as the laboratory test. Since there are many advantages such as no necessity of sample preparation, easy handling, and portability, it may provide valuable information for forensic diagnosis. In the present paper, we discuss about the diagnostic application of CO-oximeter in the field of forensic medicine

    Case report: An autopsy case of pilsicainide poisoning

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    We present a fatal case of pilsicainide poisoning. Quantitative toxicological analysis revealed that the concentrations of pilsicainide in femoral blood and urine samples were 17.5 μg/mL and 136.9 μg/mL, respectively. No morphological changes due to poisoning were observed. Based on the autopsy findings, results of the toxicological examination, and investigation by the authorities, we concluded that the cause of death was due to pilsicainide poisoning

    A Phthalimide Derivative That Inhibits Centrosomal Clustering Is Effective on Multiple Myeloma

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    Despite the introduction of newly developed drugs such as lenalidomide and bortezomib, patients with multiple myeloma are still difficult to treat and have a poor prognosis. In order to find novel drugs that are effective for multiple myeloma, we tested the antitumor activity of 29 phthalimide derivatives against several multiple myeloma cell lines. Among these derivatives, 2-(2,6-diisopropylphenyl)-5-amino-1H-isoindole-1,3- dione (TC11) was found to be a potent inhibitor of tumor cell proliferation and an inducer of apoptosis via activation of caspase-3, 8 and 9. This compound also showed in vivo activity against multiple myeloma cell line KMS34 tumor xenografts in ICR/SCID mice. By means of mRNA display selection on a microfluidic chip, the target protein of TC11 was identified as nucleophosmin 1 (NPM). Binding of TC11 and NPM monomer was confirmed by surface plasmon resonance. Immunofluorescence and NPM knockdown studies in HeLa cells suggested that TC11 inhibits centrosomal clustering by inhibiting the centrosomal-regulatory function of NPM, thereby inducing multipolar mitotic cells, which undergo apoptosis. NPM may become a novel target for development of antitumor drugs active against multiple myeloma

    Case report: Fatal poisoning caused by additive effects of two barbiturates

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    A case of fatal poisoning involving multiple psychotropic drugs is presented. Quantitative toxicological analysis showed femoral blood concentrations of pentobarbital, phenobarbital, duloxetine, acetaminophen and tramadol were 10.39, 22.57, 0.22, 0.61 and 0.22 μg/ml, respectively. We concluded that the death was due to the additive effects of two barbiturates. As both pentobarbital and phenobarbital act on gamma-aminobutyric acid (GABA) receptors, central nervous system activity was suppressed, causing respiratory depression. Additive pharmacological effects should be considered in cases of massive ingestion of multiple drugs
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