155 research outputs found

    Phase stability of long-period stacking structures in Mg-Y-Zn: A first-principles study

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    The phase stability of the long periodic structures in Mg has been investigated at finite temperature by means of first-principles calculations. Free-energy calculation, including the lattice vibration effect, clearly reveals that 14H and 18R type long periodic structures become more stable than 2H-Mg. Furthermore, the stacking fault energies from a structure of ABA (hcp) to ABC (fcc) were calculated for the isotropic lattice variation. We found that the stacking fault energy decreased by lattice expansion and went to nearly zero upon 10% expansion of the lattice. These two calculated results provide important information about the formation of long periodic stacking “ordered” (LPSO) structures in a Mg-Y-Zn system. It has been suggested that the substituted large atoms and temperature effect cooperatively generate a metastable long periodic stacking faults structure that precede LPSO formation

    Genetic diversity and structure in the Sado captive population of the Japanese crested ibis.

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    The Japanese crested ibis Nipponia nippon is a critically threatened bird. We assessed genetic diversity and structure in the Sado captive population of the Japanese crested ibis based on 24 and 50 microsatellite markers developed respectively for the same and related species. Of a total of 74 loci, 19 showed polymorphisms in the five founder birds of the population, and therefore were useful for the analysis of genetic diversity and structure. Genetic diversity measures, A, ne, He, Hoand PIC, obtained by genotyping of the 138 descendants were similar to those of other species with population bottlenecks, and thus considerably low. The low level of genetic diversity resulting from such bottlenecks was consistent with the results of lower genetic diversity measures for the Sado captive relative to the Chinese population that is the source population for the Sado group as determined using previously reported data and heterozygosity excess by Hardy-Weinberg equilibrium tests. Further, individual clustering based on the allele-sharing distance and Bayesian model-based clustering revealed that the founder genomes were equally at population in total, and with various admixture patterns at individual levels inherited by the descendants. The clustering results, together with the result of inheritance of all alleles of the microsatellites from the founders to descendants, suggest that planned mating in captive-breeding programs for the population has succeeded in maintaining genetic diversity and minimizing kinship. In addition, the Bayesian model-based clustering assumed two different components of genomes in the Sado captive Japanese crested ibis, supporting a considerably low level of genetic diversity

    Genomic analysis of antibiotic resistance for Acinetobacter baumannii in a critical care center

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    AimAcinetobacter baumannii is commonly associated with outbreaks and antibiotic‐resistant nosocomial infection. This study aimed to determine the relationship between antibiotic resistance and genotypes of A. baumannii.MethodsA study was undertaken in the critical care center (CCC) of Juntendo University Urayasu Hospital (Urayasu, Japan) between January 2012 and September 2015. Antimicrobial susceptibility tests were carried out according to the Clinical and Laboratory Standards Institute guidelines. All A. baumannii isolates were verified to carry carbapenemase genes and the ISAba1 element using polymerase chain reaction. The genetic relationship of all A. baumannii isolates was determined by pulsed‐field gel electrophoresis and multilocus sequence typing.ResultsDuring the study period, 1634 patients were admitted to the CCC. Acinetobacter baumannii was detected in 43 patients (average age, 58 ± 19 years; 67.4% men). Six patients were determined to be extensively drug‐resistant A. baumannii and 21 patients determined to be multidrug‐resistant A. baumannii. Antimicrobial susceptibility linked genotypes of A. baumannii. Molecular characterization by pulsed‐field gel electrophoresis and multilocus sequence typing showed that closely related clones of A. baumannii had spread in the CCC.ConclusionResistance to antimicrobial drugs was significantly associated with certain A. baumannii genotypic types and molecular types. Thus, we might be able to predict whether the genotype has spread in the CCC or not when the susceptibility is examined, facilitating the appropriate isolation of patients

    Single shot x-ray diffractometry in SACLA with pulsed magnetic fields up to 16 T

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    Single shot x-ray diffraction (XRD) experiments have been performed with a x-ray free electron laser (XFEL) under pulsed high magnetic fields up to 16 T generated with a nondestructive minicoil. The antiferromagnetic insulator phase in a perovskite manganaite, Pr0.6_{0.6}Ca0.4_{0.4}MnO3_{3}, is collapsed at a magnetic field of 8\approx 8 T with an emergence of the ferromagnetic metallic phase, which is observed via the accompanying lattice changes in a series of the single shot XRD. The feasibility of the single shot XRD experiment under ultrahigh magnetic fields beyond 100 T is discussed, which is generated with a portable destructive pulse magnet.Comment: 6 pages, 5 figure

    Polarization-Resolved Extreme Ultraviolet Second Harmonic Generation from LiNbO3_3

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    Second harmonic generation (SHG) spectroscopy ubiquitously enables the investigation of surface chemistry, interfacial chemistry as well as symmetry properties in solids. Polarization-resolved SHG spectroscopy in the visible to infrared regime is regularly used to investigate electronic and magnetic orders through their angular anisotropies within the crystal structure. However, the increasing complexity of novel materials and emerging phenomena hamper the interpretation of experiments solely based on the investigation of hybridized valence states. Here, polarization-resolved SHG in the extreme ultraviolet (XUV-SHG) is demonstrated for the first time, enabling element-resolved angular anisotropy investigations. In non-centrosymmetric LiNbO3_3, elemental contributions by lithium and niobium are clearly distinguished by energy dependent XUV-SHG measurements. This element-resolved and symmetry-sensitive experiment suggests that the displacement of Li ions in LiNbO3_3, which is known to lead to ferroelectricity, is accompanied by distortions to the Nb ion environment that breaks the inversion symmetry of the NbO6_{6} octahedron as well. Our simulations show that the measured second harmonic spectrum is consistent with Li ion displacements from the centrosymmetric position by \sim0.5 Angstrom while the Nb-O bonds are elongated/contracted by displacements of the O atoms by \sim0.1 Angstrom. In addition, the polarization-resolved measurement of XUV-SHG shows excellent agreement with numerical predictions based on dipole-induced SHG commonly used in the optical wavelengths. This constitutes the first verification of the dipole-based SHG model in the XUV regime. The findings of this work pave the way for future angle and time-resolved XUV-SHG studies with elemental specificity in condensed matter systems

    Identification of a novel uterine leiomyoma GWAS locus in a Japanese population

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    Uterine leiomyoma is one of the most common gynaecologic benign tumours, but its genetic basis remains largely unknown. Six previous GWAS identified 33 genetic factors in total. Here, we performed a two-staged GWAS using 13,746 cases and 70,316 controls from the Japanese population, followed by a replication analysis using 3,483 cases and 4,795 controls. The analysis identified 9 significant loci, including a novel locus on 12q23.2 (rs17033114, P = 6.12 × 10−25 with an OR of 1.177 (1.141-1.213), LINC00485). Subgroup analysis indicated that 5 loci (3q26.2, 5p15.33, 10q24.33, 11p15.5, 13q14.11) exhibited a statistically significant effect among multiple leiomyomas, and 2 loci (3q26.2, 10q24.33) exhibited a significant effect among submucous leiomyomas. Pleiotropic analysis indicated that all 9 loci were associated with at least one proliferative disease, suggesting the role of these loci in the common neoplastic pathway. Furthermore, the risk T allele of rs2251795 (3q26.2) was associated with longer telomere length in both normal and tumour tissues. Our findings elucidated the significance of genetic factors in the pathogenesis of leiomyoma

    Real-world effectiveness and safety analysis of carfilzomib-lenalidomide-dexamethasone and carfilzomib-dexamethasone in relapsed/refractory multiple myeloma: a multicenter retrospective analysis

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    Background: Little is known about the real-world survival benefits and safety profiles of carfilzomib-lenalidomide-dexamethasone (KRd) and carfilzomib-dexamethasone (Kd). Methods: We performed a retrospective analysis to evaluate their efficacy and safety in 157 patients registered in the Kansai Myeloma Forum database. Results: A total of 107 patients received KRd. Before KRd, 99% of patients had received bortezomib (54% were refractory disease), and 82% had received lenalidomide (57% were refractory disease). The overall response rate (ORR) was 68.2%. The median progression-free survival (PFS) and overall survival (OS) were 8.8 and 29.3 months, respectively. Multivariate analysis showed that reduction of the carfilzomib dose and non-IgG M protein were significantly associated with lower PFS and reduction of the carfilzomib dose and refractoriness to prior bortezomib-based regimens were significantly associated with lower OS. A total of 50 patients received Kd. Before Kd, 96% of patients had received bortezomib (54% were refractory disease). The ORR was 62.0%. The median PFS and OS were 7.1 and 20.9 months, respectively. Based on the multivariate analysis, reduction of the carfilzomib dose and International Staging System Stage III (ISS III) were significantly associated with lower PFS. Grade III or higher adverse events were observed in 48% of KRd cases and 54% of Kd cases. Cardiovascular events, cytopenia, and infections were frequent, and 4 KRd patients died due to heart failure, arrhythmia, cerebral hemorrhage, and pneumonia. Conclusion: Our analysis showed that an adequate dose of carfilzomib is important for achieving the best survival benefits in a real-world setting. Adverse effects after KRd and Kd therapy should also be considered

    Decline in Left Ventricular Ejection Fraction during Follow-up in Patients with Severe Aortic Stenosis

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    Objectives: The aim of this study was to investigate the prognostic impact of the decline in left ventricular ejection fraction (LVEF) at 1-year follow-up in patients with severe aortic stenosis (AS) managed conservatively. Background: No previous study has explored the association between LVEF decline during follow-up and clinical outcomes in patients with severe AS. Methods: Among 3, 815 patients with severe AS enrolled in the multicenter CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry in Japan, 839 conservatively managed patients who underwent echocardiography at 1-year follow-up were analyzed. The primary outcome measure was a composite of AS-related deaths and hospitalization for heart failure. Results: There were 91 patients (10.8%) with >10% declines in LVEF and 748 patients (89.2%) without declines. Left ventricular dimensions and the prevalence of valve regurgitation and atrial fibrillation or flutter significantly increased in the group with declines in LVEF. The cumulative 3-year incidence of the primary outcome measure was significantly higher in the group with declines in LVEF than in the group with no decline (39.5% vs. 26.5%; p 10% declines in LVEF at 1 year after diagnosis had worse AS-related clinical outcomes than those without declines in LVEF under conservative management. (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis Registry; UMIN000012140
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