201 research outputs found

    Josephson effect in a multi-orbital model for Sr2_{2}RuO4_{4}

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    We study Josephson current between s-wave/spin-triplet superconductor junctions by taking into account details of band structures in Sr2_{2}RuO4_{4} such as three conduction bands, spin-orbit interaction in the bulk and that at the interface. We assume five superconducting order parameters in Sr2_{2}RuO4_{4}: a chiral p-wave symmetry and four helical p-wave symmetries. We calculate current-phase relationship I(φ)I(\varphi) in these junctions, where φ\varphi is the macroscopic phase difference between two superconductors. The results for a chiral p-wave pairing symmetry show that cos(φ)\cos(\varphi) term appears in the current-phase relation due to time-reversal symmetry (TRS) breaking. On the other hand, cos(φ)\cos(\varphi) term is absent in the helical pairing states which preserve the TRS. We also study the dependence of maximum Josephson current IcI_c on an external magnetic flux Φ\Phi in a corner junction. The calculated results of Ic(Φ)I_c(\Phi) show a relation Ic(Φ)Ic(Φ)I_{c}(\Phi) \neq I_{c}(-\Phi) in a chiral state and Ic(Φ)=Ic(Φ)I_{c}(\Phi)=I_{c}(-\Phi) in a helical state. We calculate Ic(Φ)I_c(\Phi) in a corner and a symmetric SQUIDs geometry. In a symmetric SQUID geometry, the relation Ic(Φ)=Ic(Φ)I_{c}(\Phi)=I_{c}(-\Phi) is satisfied for all the pairing states and it is impossible to distinguish chiral state from helical one. On the other hand, results for a corner SQUID always show Ic(Φ)Ic(Φ)I_{c}(\Phi) \neq I_{c}(-\Phi) and Ic(Φ)=Ic(Φ)I_{c}(\Phi)=I_{c}(-\Phi) for a chiral and a helical states, respectively. Experimental tests of these relations in a corner junctions and SQUIDs may serve as a tool for unambiguous determination of the pairing symmetry in Sr2_{2}RuO4_{4}

    Effects of DNA degradation and genotype imputation on high-density SNP microarray in pairwise kinship analysis

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    High-density single nucleotide polymorphisms (SNPs) can detect distant relatives even in the context of pairwise kinship analysis. Although DNA microarrays conveniently generate genome-wide SNP data, they require large quantities of high-quality DNA. Genotyping data obtained from low-quantity and low-quality samples are likely unreliable owing to the incidence of no-called or mistyped SNPs. In this study, we examined the effects of insufficient sample densities and sample degradation on the efficacy of kinship analysis. While low DNA amounts had a minor effect, DNA degradation led to a significant increase in no-call rates and error rates. Posterior probabilities of kinship determination, calculated using the index of chromosomal sharing, were markedly lower in proportion to the no-call rates and error rates. We also investigated the effect of genotype imputation to complement the no-called genome data utilizing SNPs reference panels. We found that the posterior probability of the relative-assumed person increased with genotype complementation in case of mild degradation, even with mistyped genotypes. Therefore, DNA microarray with imputation is a promising method for analyzing forensic DNA samples taken from situations where DNA quantity and quality may be compromised, such as disaster victim identification using pairwise kinship analysis

    Renal impairment with sublethal tubular cell injury in a chronic liver disease mouse model

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    The pathogenesis of renal impairment in chronic liver diseases (CLDs) has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3, 5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy), autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet-fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the pathophysiological mechanisms of sublethal tubular cell injury

    Systemic amyloidosis with amyloid goiter: An autopsy report

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    Systemic amyloidosis is a rare but potentially lethal disease characterized by amyloid accumulation in all organs. Amyloid goiter is an extremely rare pathological lesion characterized by thyroid gland enlargement with fat deposition due to local or systemic amyloidosis. A 60 s woman with rheumatoid arthritis was found unconscious on her bed and declared dead after failed cardiopulmonary resuscitation. Postmortem computed tomography showed severe enlargement of the heart and thyroid glands, suggestive of cardiac hypertrophy and thyroidism. Histological examination revealed amorphous eosinophilic deposits with parenchymal cell destruction in all organs, including the heart and thyroid gland. Abnormal amorphous deposits in the tissues were positive for amyloid A as noted upon Congo red immunohistochemical staining and birefringence microscopy, confirming systemic amyloidosis with amyloid goiter. Serum biochemical analysis revealed increased levels of C-reactive protein; anti-cyclic citrullinated peptide antibody; creatinine kinase-myoglobin binding and N-terminal pro-brain natriuretic peptide; and thyroglobulin, free triiodothyronine, and free thyroxine, indicating systemic inflammation, active rheumatoid arthritis, heart failure, and destructive hyperthyroidism, respectively. These findings suggested that the cause of death was undiagnosed heart failure due to secondary systemic amyloid A (AA) amyloidosis related to rheumatoid arthritis. In addition, destructive hyperthyroidism caused by systemic AA amyloidosis may have also been one of the causes of death as indicated by cardiac overload. To the best of our knowledge, this is the first forensic autopsy report of cardiac amyloidosis with amyloid goiter. In conclusion, this autopsy report highlights the importance of increased awareness and early intervention for severe but treatable complications of systemic amyloidosis

    Mitochondrial fission in hepatocytes as a potential therapeutic target for nonalcoholic steatohepatitis

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    [Aim] The mitochondria are highly plastic and dynamic organelles; mitochondrial dysfunction has been reported to play causative roles in diabetes, cardiovascular diseases, and nonalcoholic fatty liver disease (NAFLD). However, the relationship between mitochondrial fission and NAFLD pathogenesis remains unknown. We aimed to investigate whether alterations in mitochondrial fission could play a role in the progression of NAFLD. [Methods] Mice were fed a standard diet or choline-deficient, L-amino acid-defined (CDAA) diet with vehicle or mitochondrial division inhibitor-1. [Results] Substantial enhancement of mitochondrial fission in hepatocytes was triggered by 4 weeks of feeding and was associated with changes reflecting the early stage of human nonalcoholic steatohepatitis (NASH), steatotic change with liver inflammation, and hepatocyte ballooning. Excessive mitochondrial fission inhibition in hepatocytes and lipid metabolism dysregulation in adipose tissue attenuated liver inflammation and fibrogenesis but not steatosis and the systemic pathological changes in the early and chronic fibrotic NASH stages (4- and 12-week CDAA feeding). These beneficial changes due to the suppression of mitochondrial fission against the liver and systemic injuries were associated with decreased autophagic responses and endoplasmic reticulum stress in hepatocytes. Injuries to other liver cells, such as endothelial cells, Kupffer cells, and hepatic stellate cells, were also attenuated by the inhibition of mitochondrial fission in hepatocytes. [Conclusions] Taken together, these findings suggest that excessive mitochondrial fission in hepatocytes could play a causative role in NAFLD progression by liver inflammation and fibrogenesis through altered cell cross-talk. This study provides a potential therapeutic target for NAFLD

    A proof-of-concept study to construct Bayesian network decision models for supporting the categorization of sudden unexpected infant death

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    Sudden infant death syndrome (SIDS) remains a leading cause of infant death in high-income countries. Supporting models for categorization of sudden unexpected infant death into SIDS/non-SIDS could reduce mortality. Therefore, we aimed to develop such a tool utilizing forensic data, but the reduced number of SIDS cases renders this task inherently difficult. To overcome this, we constructed Bayesian network models according to diagnoses performed by expert pathologists and created conditional probability tables in a proof-of-concept study. In the diagnostic support model, the data of 64 sudden unexpected infant death cases was employed as the training dataset, and 16 known-risk factors, including age at death and co-sleeping, were added. In the validation study, which included 8 new cases, the models reproduced experts' diagnoses in 4 or 5 of the 6 SIDS cases. Next, to confirm the effectiveness of this approach for onset prediction, the data from 41 SIDS cases was employed. The model predicted that the risk of SIDS in 0- to 2-month-old infants exposed to passive smoking and co-sleeping is eightfold higher than that in the general infant population, which is comparable with previously published findings. The Bayesian approach could be a promising tool for constructing SIDS prevention models
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