223 research outputs found

    High Incubation Investment of Females Paired to Attractive Males in Barn Swallows

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    Differential parental investment is the sexual selection process in which females that have acquired an attractive male invest relatively more in his offspring than females that are paired to an unattractive male. However, it is often difficult to distinguish between differential parental investment and compensation for a decrease in parental investment by an attractive mate. Using Barn Swallows Hirundo rustica gutturalis, in which males rarely participate in incubation, we investigated differential incubation investment of females. We made the following four observations: (1) Females participate in 94% of total nest attentiveness (time that eggs were incubated). (2) Female nest attentiveness was positively correlated with the ornamentation of their mates, the size of white spots in the tail, which is a measure of male attractiveness in this population. (3) Male nest attentiveness was not related to male ornaments. (4) Total nest attentiveness was positively correlated with the size of white spots in the tail. These results are consistent with differential parental investment, but not with compensation for a decrease in parental investment by a mate. Therefore, we conclude that female Barn Swallows that have acquired an attractive male invest differentially in incubation

    First-principles study on the energetics and vibrational properties of the S2 - impurity in alkali-halide crystals

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    金沢大学大学院自然科学研究科計算科学金沢大学理学部We have performed first-principles electronic structure calculations for the S2 and S2- molecules in the vacuum and found that the calculated equilibrium bond lengths and vibrational spectroscopic constants are in good agreement with the experiments as well as the previous calculations. Based on this conformation we extended these calculations to the substitutional S2- molecule in the alkali halides, such as NaCl, NaBr, NaI, KCI, KBr, KI, RbCl, RbBr, and RbI. It is found from these calculations that the S2- center aligned to [110] direction is generally favorable over those with the [100] and [111] orientations, in agreement with the experiments. We also found that the vibrational frequencies of the S2- anion in the alkali halides shift to higher energies with decreasing lattice parameters. These results suggest that the change in the bond length of the S2- anion in the matrices depends on the species of halogen atom, while the frequencies are influenced by the species of alkali atom

    Effect of cyclic bis(3′–5′)diguanylic acid and its analogs on bacterial biofilm formation

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    Cyclic bis(3′–5′)diguanylic acid (cyclic-di-GMP) functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes. We measured cyclic-di-GMP and its structural analogs such as cyclic bis(3′–5′)guanylic/adenylic acid (cyclic-GpAp), cyclic bis(3′–5′)guanylic/inosinic acid (cyclic-GpIp) and monophosphorothioic acid of cyclic-di-GMP (cyclic-GpGps) for effects on the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. We constructed a knockout mutant of SA0701, which is a GGDEF motif protein relevant to diguanylate cyclase from S. aureus 2507. We confirmed that the biofilm formation of this mutant (MS2507ΔSA0701) was reduced. Cyclic-di-GMP corresponding to physiological intracellular levels given in the culture recovered the biofilm formation of MS2507ΔSA0701, whereas its analogs did not, indicating that unlike a previous suggestion, cyclic-di-GMP was involved in the positive regulation of the biofilm formation of S. aureus and its action was structurally specific. At a high concentration (200 μM), cyclic-di-GMP and its analogs showed suppression effects on the biofilm formation of S. aureus and P. aeruginosa, and according to the quantification study using costat analysis, the suppression potential was in the order of cyclic-di-GMP, cyclic-GpGps, cyclic-GpAp and cyclic-GpIp, suggesting that the suppression effect was not strictly specific and the change of base structure quantitatively affected the suppression activity

    Usefulness of direct intratumoral administration of doxorubicin hydrochloride with an electro-osmosis–assisted pump

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    Patients receiving chemotherapy by intravenous (i.v.) or oral administration of anticancer drugs often experience side effects. In this study, an electro-osmotic flow (EO) pump was used for the direct administration of an anticancer drug with minimum side effects. Doxorubicin hydrochloride (DXR) was used as an anticancer drug, and its antitumor effect and toxicity were evaluated in comparison with i.v. administration. Balb/c female mice were subcutaneously transplanted with a breast cancer cell line (4T1/Luc) stably expressing luciferase, and 20 μL of DXR solution (1.0 mg/mL) was administered intratumorally (i.t.) at a slow rate (0.6 µL/min) using an EO pump or rapidly using a syringe. For comparison, 100 μL of DXR solution was injected through the tail vein at the same dose and a 5-times higher dose. A tumor growth inhibitory effect without significant weight loss was observed with direct i.t. administration of DXR using an EO pump. On the other hand, no suppressive tumor growth effect was observed with i.v. administration of DXR at the same dose. Although there was no significant difference in the suppression effect on tumor growth between i.t. administration with EO pump and syringe, the peripheral skin concentration of DXR were decreased after slow administration with EO pump compared with that after rapidly administration with a syringe. These results indicated that direct i.t. administration of DXR with lower dosing using an EO pump at slower administration rate may be useful for exhibiting antitumor effects and suppressing systemic side effects. In addition, the blood concentration and the peripheral skin concentration of DXR after administration at lower rate with EO pump were decreased compared with those after the rapidly administration with a syringe

    Visualization of oil-lubrication ball bearings at high rotational speeds

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    Deep-groove ball bearings for the eAxles of electric vehicles must adapt to higher rotational speed conditions because the speed of eAxle motors have been increasing as the size and weight of the motors decrease. Therefore, understanding the oil-lubricated conditions inside ball bearings at high rotational speeds is essential for optimizing their design for eAxles. To clarify the oil-lubricated conditions inside ball bearings at these high speeds, a new test apparatus was developed. This apparatus is capable of simultaneously measuring the friction torque of deep-groove ball bearings, the oil-film thickness on the rolling balls, and observing the oil distributions inside the bearings at rotational speeds up to 20,000 min-1. The oil-film thickness was measured using three-wavelength optical interferometry, and the oil distribution was observed using fluorescence. It was found that the oil-film thickness became constant at rotational speed conditions exceeding approximately 7,700 min-1. Oil starvations were observed on the raceway around the rolling ball, and these regions increased with increasing rotational speeds. Additionally, in the deep-groove ball bearing with a crown-shaped cage, the oil was mainly supplied to the rolling balls from the inner ring side through the space between the cage claws that held the ball. Moreover, the amount of mixed air tended to increase as the rotational speed increased to approximately 7,700 min-1. Those oil starvations and increasing air in oils were considered to be factors that prevent the increase in oil-film thickness. The findings of the reported study will contribute to the development of multibody dynamic technology for high-speed ball bearings necessary in electric vehicles

    E3 Ubiquitin Ligase Synoviolin Is Involved in Liver Fibrogenesis

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    Chronic hepatic damage leads to liver fibrosis, which is characterized by the accumulation of collagen-rich extracellular matrix. However, the mechanism by which E3 ubiquitin ligase is involved in collagen synthesis in liver fibrosis is incompletely understood. This study aimed to explore the involvement of the E3 ubiquitin ligase synoviolin (Syno) in liver fibrosis.The expression and localization of synoviolin in the liver were analyzed in CCl(4)-induced hepatic injury models and human cirrhosis tissues. The degree of liver fibrosis and the number of activated hepatic stellate cells (HSCs) was compared between wild type (wt) and Syno(+/-) mice in the chronic hepatic injury model. We compared the ratio of apoptosis in activated HSCs between wt and Syno(+/-) mice. We also analyzed the effect of synoviolin on collagen synthesis in the cell line from HSCs (LX-2) using siRNA-synoviolin and a mutant synoviolin in which E3 ligase activity was abolished. Furthermore, we compared collagen synthesis between wt and Syno(-/-) mice embryonic fibroblasts (MEF) using quantitative RT-PCR, western blotting, and collagen assay; then, we immunohistochemically analyzed the localization of collagen in Syno(-/-) MEF cells.In the hepatic injury model as well as in cirrhosis, synoviolin was upregulated in the activated HSCs, while Syno(+/-) mice developed significantly less liver fibrosis than in wt mice. The number of activated HSCs was decreased in Syno(+/-) mice, and some of these cells showed apoptosis. Furthermore, collagen expression in LX-2 cells was upregulated by synoviolin overexpression, while synoviolin knockdown led to reduced collagen expression. Moreover, in Syno(-/-) MEF cells, the amounts of intracellular and secreted mature collagen were significantly decreased, and procollagen was abnormally accumulated in the endoplasmic reticulum.Our findings demonstrate the importance of the E3 ubiquitin ligase synoviolin in liver fibrosis

    Assessment of F/HN-Pseudotyped Lentivirus as a Clinically Relevant Vector for Lung Gene Therapy

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    RATIONALE: Ongoing efforts to improve pulmonary gene transfer thereby enabling gene therapy for the treatment of lung diseases, such as cystic fibrosis (CF), has led to the assessment of a lentiviral vector (simian immunodeficiency virus [SIV]) pseudotyped with the Sendai virus envelope proteins F and HN. OBJECTIVES: To place this vector onto a translational pathway to the clinic by addressing some key milestones that have to be achieved. METHODS: F/HN-SIV transduction efficiency, duration of expression, and toxicity were assessed in mice. In addition, F/HN-SIV was assessed in differentiated human air-liquid interface cultures, primary human nasal epithelial cells, and human and sheep lung slices. MEASUREMENTS AND MAIN RESULTS: A single dose produces lung expression for the lifetime of the mouse (~2 yr). Only brief contact time is needed to achieve transduction. Repeated daily administration leads to a dose-related increase in gene expression. Repeated monthly administration to mouse lower airways is feasible without loss of gene expression. There is no evidence of chronic toxicity during a 2-year study period. F/HN-SIV leads to persistent gene expression in human differentiated airway cultures and human lung slices and transduces freshly obtained primary human airway epithelial cells. CONCLUSIONS: The data support F/HN-pseudotyped SIV as a promising vector for pulmonary gene therapy for several diseases including CF. We are now undertaking the necessary refinements to progress this vector into clinical trials
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