4,571 research outputs found

    Responses of heat shock protein 70 and caspase-3/7 to dietary selenomethionine in juvenile white sturgeon.

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    An 8-week feeding trial was conducted to investigate the responses of juvenile white sturgeon (Acipenser transmontanus) to elevated dietary selenium (Se) based on the determination of the RNA/DNA ratio in muscle, heat shock protein 70 (Hsp70), and caspase-3/7 in muscle and/or liver tissues. Four semi-purified test diets were prepared by adding different levels of L-selenomethionine (0, 50, 100, and 200 mg/kg diet). The analytical determinations of total Se were 2.2, 19.7, 40.1, and 77.7 mg/kg diet. The sturgeon (initial body weight: 30 ± 2 g; mean ± SEM) were raised in indoor tanks provided with flow through freshwater (18-19 °C). There were three replicates for each dietary treatment with 25 fish per replicate. The liver and muscle tissues were collected at 4 and 8 weeks after feeding the test diets. A significant interaction between duration and levels of dietary Se exposures on RNA/DNA ratio in the muscle tissue was detected (P < 0.05). Although there was no significant main effect due to the duration of dietary Se exposures (i.e., 4 weeks versus 8 weeks) on muscle RNA/DNA ratio (P ≥ 0.05), the ratio was significantly decreased with increasing dietary Se levels. Significant main effects were caused by the duration and levels of dietary Se exposures on Hsp70 in both the muscle and liver tissues, with significant increases in Hsp70 due to a longer exposure (8 weeks) and higher levels (40.1 and 77.7 mg Se/kg diet) of dietary Se. The caspase-3/7 activity in the liver were significantly higher in fish fed the diets containing 40.1 and 77.7 mg Se/kg diet than those fed the other diets. The toxic thresholds of Se in the muscle were estimated to be 32.2 and 26.6 mg Se/kg for the depressed specific growth rate and the induced Hsp70 response in muscle, respectively. This result indicated that the Hsp70 response in muscle is a more sensitive biomarker than the SGR of sturgeon for evaluating Se toxicity in white sturgeon. Results of the current study suggest that a mechanism involved with the activation of stress protein production and apoptosis protects white sturgeon from the lethal effect of Se

    Nutrition Considerations in Aquaculture: The Importance of Omega-3 Fatty Acids in Fish Development and Human Health

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    This report examines the importance of Omega-3 fatty acids to both human health and fish development. The study considers nutritional requirements for different species of fish and different stages of development, as well as methods to increase the amount of Omega-3 fatty acids in aquaculture-raised fish

    Constituting We the People

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    We study roles of the thermosphere and exosphere on the Martian ionospheric structure and ion escape rates in the process of the solar wind-Mars interaction. We employ a four-species multifluid MHD (MF-MHD) model to simulate the Martian ionosphere and magnetosphere. The coldcold thermosphere background is taken from the Mars Global Ionosphere Thermosphere Model (M-GITM) and the hothot oxygen exosphere is adopted from the Mars exosphere Monte Carlo model - Adaptive Mesh Particle Simulator (AMPS). A total of four cases with the combination of 1D (globally averaged) and 3D thermospheres and exospheres are studied. The ion escape rates calculated by adopting 1D and 3D atmospheres are similar; however, the latter are required to adequately reproduce MAVEN ionospheric observations. In addition, our simulations show that the 3D hot oxygen corona plays an important role in preventing planetary molecular ions (O2+_2^+ and CO2+_2^+) escaping from Mars, mainly resulting from the mass loading of the high-altitude exospheric O+^+ ions. The coldcold thermospheric oxygen atom, however, is demonstrated to be the primary neutral source for O+^+ ion escape during the relatively weak solar cycle 24.Comment: 21 pages, 10 figures, 4 tables, accepted for publication in Journal of Geophysical Research-Space Physic

    Fast Growth of Thin MAPbI\u3csub\u3e3\u3c/sub\u3e Crystal Wafers on Aqueous Solution Surface for Efficient Lateral-Structure Perovskite Solar Cells

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    Solar-grade single or multiple crystalline wafers are needed in large quantities in the solar cell industry, and are generally formed by a top-down process from crystal ingots, which causes a significant waste of materials and energy during slicing, polishing, and other processing. Here, a bottom-up technique that allows the growth of wafer-size hybrid perovskite multiple crystals directly from aqueous solution is reported. Single-crystalline hybrid perovskite wafers with centimeter size are grown at the top surface of a perovskite precursor solution. As well as saving raw materials, this method provides unprecedented advantages such as easily tunable thickness and rapid growth of the crystals. These crystalline wafers show high crystallinity, broader light absorption, and a long carrier recombination lifetime, comparable with those of bulk single crystals. Lateral-structure perovskite solar cells made of these crystals demonstrate a record power conversion efficiency of 5.9%. Includes supplementary materials

    RFormer: Transformer-based Generative Adversarial Network for Real Fundus Image Restoration on A New Clinical Benchmark

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    Ophthalmologists have used fundus images to screen and diagnose eye diseases. However, different equipments and ophthalmologists pose large variations to the quality of fundus images. Low-quality (LQ) degraded fundus images easily lead to uncertainty in clinical screening and generally increase the risk of misdiagnosis. Thus, real fundus image restoration is worth studying. Unfortunately, real clinical benchmark has not been explored for this task so far. In this paper, we investigate the real clinical fundus image restoration problem. Firstly, We establish a clinical dataset, Real Fundus (RF), including 120 low- and high-quality (HQ) image pairs. Then we propose a novel Transformer-based Generative Adversarial Network (RFormer) to restore the real degradation of clinical fundus images. The key component in our network is the Window-based Self-Attention Block (WSAB) which captures non-local self-similarity and long-range dependencies. To produce more visually pleasant results, a Transformer-based discriminator is introduced. Extensive experiments on our clinical benchmark show that the proposed RFormer significantly outperforms the state-of-the-art (SOTA) methods. In addition, experiments of downstream tasks such as vessel segmentation and optic disc/cup detection demonstrate that our proposed RFormer benefits clinical fundus image analysis and applications. The dataset, code, and models are publicly available at https://github.com/dengzhuo-AI/Real-FundusComment: IEEE J-BHI 2022; The First Benchmark and First Transformer-based Method for Real Clinical Fundus Image Restoratio

    Epidemiological survey of school-age children with low vision in Zhouqu County of Gannan Tibetan autonomous prefecture of Gansu province

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    AIM: To have a detailed picture of school-age children's eyesight status, and the main factors that caused their low vision in Zhouqu County of Gannan Tibetan autonomous prefecture of Gansu province. METHODS: The census work of knowing school-age children's eyesight status was implemented through visual inspection, conventional ophthalmic examination, optometry checks, etc. The results were compared with other domestic epidemiological data. RESULTS: Altogether 536 people with low vision were identified through survey and the rate was 21.12%. Among those people, the number of myopia patients accounted for 80.59% and the prevalence rate was 17.02%. Besides, the prevalence rate of presbyopia was 2.05%, amblyopia 2.76%, strabismus 1.02%, ocular trauma 0.95%, and congenital eye disease 0.71%. CONCLUSION: The prevalence rate of low vision was related with several factors such as gender and nationality. The rate increases with age and the myopia is the primary element that causes low vision

    In-silico investigations into natural products as nonnucleoside DNA methyltransferase 1 inhibitors for treating epi-mutation in gastric cancer

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    Purpose: To explore in silico methods to search for the best reported non-nucleoside DNA methyltransferase 1 (DNMT1) inhibitor of epimutation in gastric cancer.Methods: A dataset of reported non-nucleoside DNMT1 inhibitors was used to target the active site of crystallized DNMT1 protein. Molecular docking simulations were carried out using AutoDock 4.2.6 l. The results were analyzed using Discovery studio visualizer.Results: In silico analysis of known natural non-nucleoside DNMT1 inhibitors gave genistein as the top ranked compound with ΔG of -6.39 Kcal/mol. Further, the results indicated that epigallocatechin gallate and curcumin are poor non-nucleoside DNMT1 inhibitors, as the in silico data suggest that they failed to bind to the catalytic site of DNMT1.Conclusion: The results indicate that genistein is the top rated compound for DNMT1 inhibition. Previous in vitro and in vivo work by other researchers seem to validate the findings of the study.Keywords: Epi-mutation, DNA methyltransferase, Non-nucleoside, DNMT1 inhibitor, Dockin
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