863 research outputs found

    Dynamic simulation of nonlinear vibration on large horizontal axis turbine blades using a finite differential method

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    According to Kallesøe’s model of turbine blades, two methods were developed to solve the nonlinear vibration of blades, namely, nonlinear non-autonomous system with gravity effect and nonlinear autonomous system without gravity effect. The equations were changed into the mass and stiffness matrices using a finite difference method on the boundary conditions of cantilever beams. By the time discretion methods and the Matlab vibration toolboxes, the displacements and the phase tracks of blade tip were simulated in the directions of lead-lag, flapping and twisting. Then the amplitude-frequency and phase-frequency characteristic curves were plotted by the analysis of non-autonomous rotating turbine blades. Finally all simulation results were compared among the nonlinear system and the linear system. The nature frequencies and the convergence of the systems were also discussed

    2,2-Dimethyl-5-[(pyridin-2-yl­amino)­methyl­idene]-1,3-dioxane-4,6-dione

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    In the title compound, C12H12N2O4, the dihedral angle between the pyridine and enamine planes is 3.5 (3)°, while the angle between the dioxanedione (seven atoms) and enamine planes is 4.6 (3)°. The dioxane ring approximates an envelope conformation

    5-(1H-Indol-3-yl­methyl­idene)-2,2-di­methyl-1,3-dioxane-4,6-dione

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    In the title compound, C15H13NO4, the conjugated double-bond system between the two rings adopts a cis configuration and there is an intra­molecular indole–ketone C—H⋯O inter­action. The indole N—H group forms an inter­molecular hydrogen bond with a ketone O-atom acceptor, giving a chain structure along the ab direction. The O-heterocyclic ring adopts a boat conformation and makes a dihedral angle of 16.72 (6)° with the indole ring system

    Factors Associated with Myopia in School Children in China: The Beijing Childhood Eye Study

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    Purpose: To assess factors associated with myopia in school children in rural and urban parts of Greater Beijing. Methods: The Beijing Pedriatic Eye Study was a population-based cross-sectional study, in which one school of each level (primary, junior high, senior high) was randomly selected from nine randomly selected districts out of 18 districts of Greater Beijing. The children underwent non-cylcoplegic refractometry and their parents an interview. Results: Of 16,771 eligible students, 15,066 (89.8%) children (7,769 (51.6%) girls) participated, with 8,860 (58.8%) participants living in the rural region. Mean age was 13.263.4 years (range:7–18 years). In multivariate analysis, prevalence of myopia (defined as #21.00 diopters) was associated with higher age (Odds ratio(OR):1.37; 95% confidence interval(CI):1.35,1.39), female gender (OR:1.35;95%CI:1.25,1.47), key school type (OR:0.77;95%CI: 0.70,0.85), higher family income (OR:1.04;95%CI:1.01,1.07), parental myopia (OR:1.46;95%CI:1.40,1.53), dim reading illumination (OR:0.93;95%CI: 0.88,0.98), longer daily studying duration (OR:1.10;95%CI:1.06,1.15), shorter duration of watching television (or computer) (OR:0.93;95%CI:0.89,0.97), higher self-reported protein intake (OR:0.94;95%CI:0.90,0.99), feeling well about life and status (OR:0.93;95%CI:0.89,0.98), and feeling tired or dizzy (OR:0.94;95%CI:0.91,0.97). Prevalence of high myopia (defined as #26.00 diopters) was associated with higher age (OR:1.43;95%CI:1.38, 1.48), key school type (OR:0.61;95%CI:0.49,0.74), family income (OR:1.07;95%CI:1.02,1.13), parental myopia (OR:1.65;95%CI:1.54,1.76), dim reading illumination (OR:0.86;95%CI:0.77,0.96), less rest during studying (OR:1.18;95%CI:1.10,1.27), feeling well about life and studying (OR:0.88;95%CI: 0.81,0.96) and feeling dizzy or tired (OR:0.93;95%CI:0.87,0.99). Prevalence of high myopia (defined as #28.00 diopters) was significantly associated with higher age (OR:1.39;95%CI:1.31,1.48;), key school type (OR:0.61;95%CI:0.42,0.88) and parental myopia (OR:1.87;95%CI:1.66,2.12). Conclusions: Myopia in school children in Greater Beijing was associated with higher age, female gender, school type, parental myopia, higher socioeconomic background, dim reading illumination, longer daily studying duration, less rest during study, shorter duration of watching television (or computer), higher self-reported protein intake, feeling well about life and status, and feeling tired and dizzy

    荆州区农村人口初发糖尿病胰岛功能的现状跟踪调查*

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    Objective: To study the change of islet function in patients with incipient diabetic characteristics through incipient diabetic tracking observation of the islet function in patients of Jingzhou area. Methods: Selection of 1220 cases of patients with diabetes mellitus in Jingzhou area as research object at the beginning, 12 months follow-up, the clinic after 3 months, 6 months and 12 months, all patients to detect blood sugar change, c-peptide release quantity, calculate insulin secretion index (HOMA -β) and insulin resistance index (HOMA IR), summarizes the characteristic of islet function in patients with changes. Results: ① The patients restored to basic standard blood sugar in 3 months by drug treatment, and the patient's blood glucose levels not seen obvious fluctuation after 6 months and 12 months; ② During follow-up, patients with diabetes sustained c-peptide release quantity reduction, and in three months after treatment, c-peptide release decreased obviously, and see a doctor at 6 months and 12 months after the comparison, the difference was statistically significant (P < 0.05). ③ During follow-up, insulin capacity was decreasing among patients with diabetes, within three months after the doctor had the greatest reduction, the difference was statistically significant (P < 0.05); ④ During follow-up, island hormone decreasing index, insulin resistance index continued to rise among patients with diabetes, and 6 months and 12 months, the most significant variations in 3 months (P < 0.05). Conclusion: With the extension of course, the pancreatic islet function in patients with early onset diabetes decreased gradually. It could be proved that there is a significant correlation between the two and especially seen in obvious function decline of pancreatic islets among the patients within 3 months.目的  通过对荆州区初发糖尿病患者的胰岛功能进行跟踪观察,探讨发现初发糖尿病患者胰岛功能的变化特点。方法  选取荆州区1220例初发糖尿病患者作为观察对象,跟踪随访12个月,在就诊后的3个月、6个月及12个月时,全部患者检测血糖变化、C-肽释放量,计算胰岛素分泌指数(HOMA-β)及胰岛素抵抗指数(HOMA-IR),观察总结患者的胰岛功能变化特点。结果  (1)通过药物治疗,患者血糖在3个月时基本达标,6个月及12个月时,患者的血糖水平未见明显波动;(2)随访期间,糖尿病患者C-肽释放量持续降低,且在就诊后3个月内,C-肽释放量下降明显,与就诊后6个月时及12个月时比较,差异有统计学意义(P<0.05)。(3)随访期间,糖尿病患者胰岛素放量持续降低,就诊后3个月内下降最明显,差异有统计学意义(P<0.05);(4)随访期间,糖尿病患者胰岛素分泌指数持续降低,胰岛素抵抗指数持续升高,且与6个月时和12个月时比较,3个月时变化幅度最为显著(P<0.05)。结论  随着病程的延长,初发糖尿病患者胰岛功能逐渐降低,二者具有显著相关性,且3个月内患者的胰岛功能下降最为显著

    High speed self-testing quantum random number generation without detection loophole

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    Quantum mechanics provides means of generating genuine randomness that is impossible with deterministic classical processes. Remarkably, the unpredictability of randomness can be certified in a self-testing manner that is independent of implementation devices. Here, we present an experimental demonstration of self-testing quantum random number generation based on an detection-loophole free Bell test with entangled photons. In the randomness analysis, without the assumption of independent identical distribution, we consider the worst case scenario that the adversary launches the most powerful attacks against quantum adversary. After considering statistical fluctuations and applying an 80 Gb ×\times 45.6 Mb Toeplitz matrix hashing, we achieve a final random bit rate of 114 bits/s, with a failure probability less than 10510^{-5}. Such self-testing random number generators mark a critical step towards realistic applications in cryptography and fundamental physics tests.Comment: 34 pages, 10 figure

    UGROŽENE VRSTE RIBA U SVIJETU: Hucho taimen (Pallas, 1773)

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    Taimen Hucho taimen (Pallas, 1773) was once common in China, Russia, Kazakhstan and Mongolia but is disappearing now from its native region. This vulnerable species has considerable ecological importance but there are few data available on its biology. The limited available data on its systematics, distribution, ecology, reproduction and threats are summarized and discussed.Taimen Hucho taimen (Pallas, 1773) je nekoć bio čest u Kini, Rusiji, Kazahstanu i Mongoliji, ali sada nestaje iz svojih prirodnih staništa. Ova osjetljiva vrsta ima značajnu ekološku važnost iako ima malo podataka o njenoj biologiji. Dostupni podaci vezani uz sistematiku, distribuciju, ekologiju, razmnožavanje i prijetnje su ograničeni te su sažeti i o njima se raspravlja

    Mechanism and consequences for avoidance of superparasitism in the solitary parasitoid Cotesia vestalis

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    A parasitoid's decision to reject or accept a potential host is fundamental to its fitness. Superparasitism, in which more than one egg of a given parasitoid species can deposit in a single host, is usually considered sub-optimal in systems where the host is able to support the development of only a single parasitoid. It follows that selection pressure may drive the capacity for parasitoids to recognize parasitized hosts, especially if there is a fitness cost of superparasitism. Here, we used microsatellite studies of two distinct populations of Cotesia vestalis to demonstrate that an egg laid into a diamondback moth (Plutella xylostella) larva that was parasitized by a conspecific parasitoid 10 min, 2 or 6 h previously was as likely to develop and emerge successfully as was the first-laid egg. Consistent with this, a naive parasitoid encountering its first host was equally likely to accept a healthy larva as one parasitized 10 min prior, though handling time of parasitized hosts was extended. For second and third host encounters, parasitized hosts were less readily accepted than healthy larvae. If 12 h elapsed between parasitism events, the second-laid egg was much less likely to develop. Discrimination between parasitized and healthy hosts was evident when females were allowed physical contact with hosts, and healthy hosts were rendered less acceptable by manual injection of parasitoid venom into their hemolymph. Collectively, these results show a limited capacity to discriminate parasitized from healthy larvae despite a viability cost associated with failing to avoid superparasitism

    Suppression of Tumor Energy Supply by Liposomal Nanoparticle-Mediated Inhibition of Aerobic Glycolysis

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    Aerobic glycolysis enables cancer cells to rapidly take up nutrients (e.g., nucleotides, amino acids, and lipids) and incorporate them into the biomass needed to produce a new cell. In contrast to existing chemotherapy/radiotherapy strategies, inhibiting aerobic glycolysis to limit the adenosine 5′-triphosphate (ATP) yield is a highly efficient approach for suppressing tumor cell proliferation. However, most, if not all, current inhibitors of aerobic glycolysis cause significant adverse effects because of their nonspecific delivery and distribution to nondiseased organs, low bioavailability, and a narrow therapeutic window. New strategies to enhance the biosafety and efficacy of these inhibitors are needed for moving them into clinical applications. To address this need, we developed a liposomal nanocarrier functionalized with a well-validated tumor-targeting peptide to specifically deliver the aerobic glycolysis inhibitor 3-bromopyruvate (3-BP) into the tumor tissue. The nanoparticles effectively targeted tumors after systemic administration into tumor-bearing mice and suppressed tumor growth by locally releasing 3-BP to inhibit the ATP production of the tumor cells. No overt side effects were observed in the major organs. This report demonstrates the potential utility of the nanoparticle-enabled delivery of an aerobic glycolysis inhibitor as an anticancer therapeutic agent

    Targeting the Vasculature of Colorectal Carcinoma with a Fused Protein of (

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    Purpose. Truncated tissue factor (tTF) fusion protein targeting tumor vasculature can induce tumor vascular thrombosis and necrosis. Here, we generated (RGD)3-tTF in which three arginine-glycine-aspartic (RGD) targeting integrin αvβ3 and tTF induce blood coagulation in tumor vessels. Methods. The bioactivities of (RGD)3-tTF including coagulation activity, FX activation, and binding with integrin αvβ3 were performed. The fluorescent labeled (RGD)3-tTF was intravenously injected into tumor-bearing mice and traced in vivo. The tumor growth, volume, blood vessel thrombosis, tumor necrosis, and survival time of mice treated with (RGD)3-tTF were evaluated. Results. The clotting time and FX activation of (RGD)3-tTF were similar to that of TF (P>0.05) but different with that of RGD (P<0.05). (RGD)3-tTF presented a higher binding with αvβ3 than that of RGD and TF at the concentration of 0.2 μmol/L (P<0.05). (RGD)3-tTF could specifically assemble in tumor and be effective in reducing tumor growth by selectively inducing tumor blood vessels thrombosis and tumor necrosis which were absent in mice treated with RGD or TF. The survival time of mice treated with (RGD)3-tTF was higher than that of mice treated with TF or RGD (P<0.05). Conclusion. (RGD)3-tTF may be a promising strategy for the treatment of colorectal cancer
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