43 research outputs found

    Spatio-temporal variability in life cycle strategy of four pelagic Antarctic copepods: Rhincalanus gigas, Calanoides acutus, Calanus propinquus and Metridia gerlachei

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    Spatio-temporal variability in life cycle strategy of four pelagic Antarctic copepods, Rhincalanus gigas, Calanoides acutus, Calanus propinquus and Metridia gerlachei was studied, including their copepodite stage composition, using the multiyear samples taken off east Antarctica (90-160°E) in March 1988-1996. Except for R. gigas, the rare occurrence of adults indicated that the spawning activities ceased by mid-March in this research area. Younger copepodite stages appeared for C. propinquus compared to C. acutus, suggesting the late reproduction or slow growth in the former. Multiple regression analysis on the relationship between environmental variables and the copepodite stage composition showed that the population matured earlier in the warmer area for C. acutus, C. propinquus and M. gerlachei. The study demonstrated that the three species flexibly changed timing of the reproduction and development, and shifted their life cycle from one year to two years in the southern Antarctic Circumpolar Current (ACC) area, responding to spatio-temporal environmental change caused by meandering of the ACC

    Effects of Fe on microstructures and mechanical properties of Ti-15Nb-25Zr-(0, 2, 4, 8)Fe alloys prepared by spark plasma sintering

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    Biomedical Ti-15Nb-25Zr-(0, 2, 4, 8)Fe (mol%) alloys are prepared by mixing pure element powders and spark plasma sintering (SPS). Specimens with diameters of 20 mm and thicknesses of 3 mm are obtained by sintering at 1000°C for 10 min followed by cooling in the furnace. Some of the specimens are then heat-treated at 900°C for 1 h followed by water quenching. Zr and Fe are dissolved in Ti; however, segregation of Nb is observed in all of the alloys. The β and α′′ phases are observed in the as-sintered and heat-treated specimens owing to the insufficient diffusion of the alloying elements. Fe stabilizes the β phase and provides a solution-strengthening effect. With the increase in the Fe content in the as-sintered specimen, the compressive strength and micro-Vickers hardness are improved in the Ti-15-Nb-25Zr-(0, 2, 4)Fe alloys and slightly decreased in Ti-15-Nb-25Zr-8Fe. The as-sintered Ti-15Nb-25Zr-4Fe alloy exhibits the maximum compressive strength of 1740 MPa. Although the plasticity is decreased by the Fe addition, a fracture strain of approximately 17% is obtained for Ti-15Nb-25Zr-4Fe, indicating a good plasticity. The heat treatment cannot eliminate the segregation of Nb, but can improve the plasticity and slightly increase the strengths of Ti-15Nb-25-Zr(0, 2, 4)Fe. Moreover, the heat-treated Ti-15Nb-25Zr-8Fe exhibits a high strength of approximately 1780 MPa and fracture strain of approximately 19%. Therefore, good comprehensive mechanical properties, including high strengths, high hardnesses, and good plasticities, can be obtained in Fe-added β-Ti alloys prepared by SPS and subsequent optional short heat treatment.Li Q., Yuan X., Li J., et al. Effects of Fe on microstructures and mechanical properties of Ti-15Nb-25Zr-(0, 2, 4, 8)Fe alloys prepared by spark plasma sintering. Materials Transactions 60, 1763 (2019); https://doi.org/10.2320/matertrans.ME201913

    Microstructure and mechanical properties of Ti–Nb–Fe–Zr alloys with high strength and low elastic modulus

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    Zr was added to Ti–Nb–Fe alloys to develop low elastic modulus and high strength β-Ti alloys for biomedical applications. Ingots of Ti–12Nb–2Fe–(2, 4, 6, 8, 10)Zr (at.%) were prepared by arc melting and then subjected to homogenization, cold rolling, and solution treatments. The phases and microstructures of the alloys were analyzed by optical microscopy, X-ray diffraction, and transmission electron microscopy. The mechanical properties were measured by tensile tests. The results indicate that Zr and Fe cause a remarkable solid-solution strengthening effect on the alloys; thus, all the alloys show yield and ultimate tensile strengths higher than 510 MPa and 730 MPa, respectively. Zr plays a weak role in the deformation mechanism. Further, twinning occurs in all the deformed alloys and is beneficial to both strength and plasticity. Ti–12Nb–2Fe–(8, 10)Zr alloys with metastable β phases show low elastic modulus, high tensile strength, and good plasticity and are suitable candidate materials for biomedical implants.LI Q., HUANG Q., LI J.j., et al. Microstructure and mechanical properties of Ti–Nb–Fe–Zr alloys with high strength and low elastic modulus. Transactions of Nonferrous Metals Society of China, 32, 2, 503. https://doi.org/10.1016/S1003-6326(22)65811-4

    Low springback and low Young’s modulus in Ti-29-Nb-13Ta-4.6Zr alloy modified by Mo addition

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    Deformation-induced higher Young’s modulus can satisfy the contradictory requirements of Ti alloys for spinal-fixation applications, which demand a high Young’s modulus to reduce springback during operations and a low Young’s modulus to prevent stress shielding effect for patients after surgeries. In this study, TNTZ-(1, 3, 5)Mo are designed by adding Mo and Ti to Ti-29-Nb-13Ta-4.6Zr (TNTZ) in order to maintain low initial Young’s modulus and achieve low springback. All the solutionized alloys show single β phase with increasing the β stability by Mo addition. They show low Young’s moduli less than 65 GPa, similar ultimate tensile strength of 650 MPa and elongation around 20%. The springback of TNTZ-3Mo and TNTZ-5Mo is lower than that of TNTZ and TNTZ-1Mo owing to their more stable β phase. After cold rolling, TNTZ-3Mo shows the largest increasing ratio of 25% in Young’s modulus and the highest ultimate tensile strength owning to the appearance of deformation-induced ω phase. With the low initial Young’s modulus of 59 GPa, TNTZ-3Mo is a potential candidate to make the spinal rods in spinal fixation devices.Li Q., Qi Q., Li J., et al. Low springback and low Young’s modulus in Ti-29-Nb-13Ta-4.6Zr alloy modified by Mo addition. Materials Transactions 60, 1755 (2019); https://doi.org/10.2320/matertrans.ME201912

    Modification of single-nucleotide polymorphism in a fully humanized CYP3A mouse by genome editing technology

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    Abe, S., Kobayashi, K., Oji, A. et al. Modification of single-nucleotide polymorphism in a fully humanized CYP3A mouse by genome editing technology. Sci Rep 7, 15189 (2017). https://doi.org/10.1038/s41598-017-15033-

    A prospective compound screening contest identified broader inhibitors for Sirtuin 1

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    Potential inhibitors of a target biomolecule, NAD-dependent deacetylase Sirtuin 1, were identified by a contest-based approach, in which participants were asked to propose a prioritized list of 400 compounds from a designated compound library containing 2.5 million compounds using in silico methods and scoring. Our aim was to identify target enzyme inhibitors and to benchmark computer-aided drug discovery methods under the same experimental conditions. Collecting compound lists derived from various methods is advantageous for aggregating compounds with structurally diversified properties compared with the use of a single method. The inhibitory action on Sirtuin 1 of approximately half of the proposed compounds was experimentally accessed. Ultimately, seven structurally diverse compounds were identified

    CXCL9, CXCL10, and CXCL11; biomarkers of pulmonary inflammation associated with autoimmunity in patients with collagen vascular diseases-associated interstitial lung disease and interstitial pneumonia with autoimmune features.

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    IntroductionInterstitial lung disease (ILD) is a heterogeneous group of diseases characterized by varying degrees of lung inflammation and/or fibrosis. We investigated biomarkers to infer whether patients with collagen vascular diseases associated ILD (CVD-ILD) and interstitial pneumonia with autoimmune features (IPAF) benefit from immunosuppressive therapy.Materials and methodsWe retrospectively investigated patients with CVD-ILD, IPAF, and idiopathic pulmonary fibrosis (IPF) between June 2013 and May 2017 at our department. First, we assessed differences in serum and bronchoalveolar lavage fluid (BALF) levels of cytokines between groups. Second, we assessed the associations of patient's clinical variables with serum and BALF levels of those cytokines that were different between groups. Finally, we assessed the associations of diagnosis and response to immunosuppressive therapy with serum levels of those cytokines that were different between groups.ResultsWe included 102 patients (51 with IPF, 35 with IPAF, and 16 with CVD-ILD). Serum and BALF levels of CXCL9, CXCL10, and CXCL11 were significantly elevated in patients with IPAF or CVD-ILD compared with those in patients with IPF. BALF levels of CXCL9 and CXCL10 were correlated with the percentages of lymphocytes and macrophages in BALF. Serum levels of CXCL9 and CXCL10 were correlated with BALF levels. Serum levels of CXCL9, CXCL10, and CXCL11 were correlated C-reactive protein, percent predicted forced vital capacity, alveolar-arterial oxygen difference, and the percentages of lymphocytes and macrophages in BALF. Serum levels of CXCL9, CXCL10, and CXCL11 showed moderate accuracy to distinguish patients with CVD-ILD from those with IPAF and IPF. Pre-treatment serum levels of CXCL9 and CXCL11 showed strong positive correlations with the annual forced vital capacity changes in patients with IPAF and CVD-ILD treated with immunosuppressive drugs.ConclusionsSerum CXCL9, CXCL10, and CXCL11 are potential biomarkers for autoimmune inflammation and predictors of the immunosuppressive therapy responses in ILD with background autoimmunity
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