73 research outputs found

    Hormonal regulation of ovarian bursa fluid in mice and involvement of aquaporins.

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    In rodent species, the ovary and the end of oviduct are encapsulated by a thin membrane called ovarian bursa. The biological functions of ovarian bursa remain unexplored despite its structural arrangement in facilitating oocytes transport into oviduct. In the present study, we observed a rapid fluid accumulation and reabsorption within the ovarian bursa after ovarian stimulation (PMSG-primed hCG injection), suggesting that the ovarian bursa might play an active role in regulating local fluid homeostasis around the timing of ovulation. We hypothesized that the aquaporin proteins, which are specialized channels for water transport, might be involved in this process. By screening the expression of aquaporin family members (Aqp1-9) in the ovarian tissue and isolated ovarian bursa (0, 1, 2 and 5 h after hCG injection), we found that AQP2 and AQP5 mRNA showed dynamic changes after hCG treatment, showing upregulation at 1-2 h followed by gradually decrease at 5 h, which is closely related with the intra-bursa fluid dynamics. Further immunofluorescence examinations of AQP2 and AQP5 in the ovarian bursa revealed that AQP2 is specifically localized in the outer layer (peritoneal side) while AQP5 localized in the inner layer (ovarian side) of the bursa, such cell type specific and spatial-temporal expressions of AQP2 and 5 support our hypothesis that they might be involved in efficient water transport through ovarian bursa under ovulation related hormonal regulation. The physiological significance of aquaporin-mediated water transport in the context of ovarian bursa still awaits further clarification

    MicroRNA and transcription factor co-regulatory network analysis reveals miR-19 inhibits CYLD in T-cell acute lymphoblastic leukemia

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    T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy. The understanding of its gene expression regulation and molecular mechanisms still remains elusive. Started from experimentally verified T-ALL-related miRNAs and genes, we obtained 120 feed-forward loops (FFLs) among T-ALL-related genes, miRNAs and TFs through combining target prediction. Afterwards, a T-ALL miRNA and TF co-regulatory network was constructed, and its significance was tested by statistical methods. Four miRNAs in the miR-17–92 cluster and four important genes (CYLD, HOXA9, BCL2L11 and RUNX1) were found as hubs in the network. Particularly, we found that miR-19 was highly expressed in T-ALL patients and cell lines. Ectopic expression of miR-19 represses CYLD expression, while miR-19 inhibitor treatment induces CYLD protein expression and decreases NF-κB expression in the downstream signaling pathway. Thus, miR-19, CYLD and NF-κB form a regulatory FFL, which provides new clues for sustained activation of NF-κB in T-ALL. Taken together, we provided the first miRNA-TF co-regulatory network in T-ALL and proposed a model to demonstrate the roles of miR-19 and CYLD in the T-cell leukemogenesis. This study may provide potential therapeutic targets for T-ALL and shed light on combining bioinformatics with experiments in the research of complex diseases

    Hydrodynamic performance of a pile-supported OWC breakwater: An analytical study

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    A pile-supported OWC breakwater is a novel marine structure in which an oscillating water column (OWC) is integrated into a pile-supported breakwater, with a dual function: generating carbon-free energy and providing shelter for port activities by limiting wave transmission. In this work we investigate the hydrodynamics of this novel structure by means of an analytical model based on linear wave theory and matched eigenfunction expansion method. A local increase in the back-wall draft is adopted as an effective strategy to enhance wave power extraction and reduce wave transmission. The effects of chamber breadth, wall draft and air chamber volume on the hydrodynamic performance are examined in detail. We find that optimizing power take-off (PTO) damping for maximum power leads to both satisfactory power extraction and wave transmission, whereas optimizing for minimum wave transmission penalizes power extraction excessively; the former is, therefore, preferable. An appropriate large enough air chamber volume can enhance the bandwidth of high extraction efficiency through the air compressibility effect, with minimum repercussions for wave transmission. Meanwhile, the air chamber volume is found to be not large enough for the air compressibility effect to be relevant at engineering scales. Finally, a two-level practical optimization strategy on PTO damping is adopted. We prove that this strategy yields similar wave power extraction and wave transmission as the ideal optimization approach

    The association of metabolic dysfunction-associated steatotic liver disease (MASLD) with the risk of myocardial infarction: a systematic review and meta-analysis

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    AbstractObjective While studies have documented how metabolic dysfunction-associated steatotic liver disease (MASLD) can contribute to cardiovascular disease (CVD), whether MASLD is associated with myocardial infarction (MI) remains debateable. Herein, we systematically reviewed published articles and performed a meta-analysis to determine the relationship between MASLD and MI risk.Methods PubMed, MEDLINE, Embase, Web of Science, CNKI, CBM, VIP, and WanFang databases were searched, and the DerSimonian Laird method was used to obtain hazard ratios (HRs) for binary variables to assess the correlation between MASLD and MI risk. Subgroup analyses for the study region, MASLD diagnosis, quality score, study design, and follow-up time were conducted simultaneously for the selected studies retrieved from the time of database establishment to March 2022. All study procedures were independently conducted by two investigators.Results The final analysis included seven articles, including eight prospective and two retrospective cohort studies. The MI risk was higher among MASLD patients than among non-MASLD patients (HR = 1.26; 95% CI: 1.08-1.47, p = 0.003). The results of the subgroup analysis of the study region revealed an association of MASLD with MI risk among Americans and Asians, but not in Europeans. Subgroup analyses of MASLD diagnosis showed that ultrasonography and other (fatty liver index[FLI] and computed tomography [CT)]) diagnostic methods, but not international classification of disease (ICD), increased the risk of MI. Subgroup analysis of the study design demonstrated a stronger relationship between MASLD and MI in retrospective studies but not in prospective studies. Subgroup analysis based on the follow-up duration revealed the association of MASLD with MI risk in cases with < 3 years of follow-up but not with ≥3 years of follow-up.Conclusion MASLD increases the risk of MI, independent of traditional risk factors

    Comparison of the daily global solar radiation from different data sources in Northwest China climate

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    The solar radiation data are of high importance to the solar energy systems. Conventional methods to obtain the solar radiation data are from weather stations, solar radiation models, commercial software databases, and field measurements. In the present study, a new daily global solar radiation model is proposed, by combining the quadratic function of sunshine fraction and sine function of the day of the year. The solar radiation model calculated data are then compared with China Meteorological Data Sharing System (CMDSS) data, TRNSYS data, and field-measured data in Northwest China climate. It is found that the newly proposed solar radiation model has better performance than the other nine solar radiation models in the literature. The solar radiation model calculated data fit well with the CMDSS annually average data. The TRNSYS data are a bit larger than the CMDSS annually average data in summer half year and a little smaller than those in winter half year. The solar radiation model and the CMDSS annually average data have the best correlation, whereas the TRNSYS data and the field-measured data have the worst correlation. The solar radiation model calculated data have the best correlation with the other three data sources

    Design and simulation of a geothermal-solar combined chimney power plant

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    The solar chimney power plant (SCPP) is dominated by the solar radiation, and therefore its discontinuous operation is an unavoidable problem. In this paper, low temperature geothermal water is introduced into the SCPP for overcoming this problem. Based on a developed transient model, theoretical analyses are carried out to investigate the performance of the geothermal-solar chimney power plant (GSCPP) with main dimensions the same as the Manzanares prototype in Spain. Three operation models, viz. the full solar model, the full geothernial model and the geothermal-solar combined model are compared in typical summer and winter days and throughout the year. It is found that the GSCPP can attractively run in the GSM to deliver power continuously. Due to the ambient-dependant geothermal water outlet temperature, introducing the geothermal water makes greater contribution in winter days than in summer days, in the night than in the daytime. Power generation under GSM is larger than the sum of FSM and FGM. GSM is not the simple superposition of FSM and FGM, but makes better utilization of solar and geothermal energy. In addition, introducing high temperature and mass flow rate geothermal water can doubled and redoubled improve the GSCPP's power capacity. (C) 2014 Elsevier Ltd. All rights reserved

    Economic analysis of solar chimney power plants in Northwest China

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    Solar chimney power plant (SCPP) with a long life span is a promising large-scale solar thermal utilization technology. This paper performs an economic analysis for the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP) in Northwest China. Cash flows are influenced by many factors including the investment, the payback period, the inflation rate, and the sale price of solar electricity. The techno-economic analyses of the CSCPPs and SSCPPs are performed taking Lanzhou, China as a case study. The results show that the SCPP investment is influenced by both its configuration and the material price, and the SSCPP is more cost-effective than the CSCPP during the system life span. In addition, the SCPP with large power capacity holds good competitiveness with the conventional fossil fuel combustion plants. The economic evaluation of building SCPPs in Northwest China is of high significance considering the local abundant solar radiation, favorable government policy, and under-developing economics. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4798434

    Models for Calculating Daily Global Solar Radiation from Air Temperature in Humid Regions-A case study

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    Solar radiation is an important parameter for the proper design of solar energy conversion devices and building energy systems. As air temperature is readily available at most meteorological stations, the models based on air temperature for estimating solar radiation are more attractive and practical. To improve the air temperature-based models' performance in humid regions, the effects of seasonality and relative humidity are introduced to (Hargreaves and Samani [1982]: Journal of the Irrigation and Drainage Division 108, 225-230) and (Bristow and Campbell (BC) [1984]: Agricultural and Forest Meteorology 31, 159-166) correlations, and thus six candidate models are proposed in this article. These models are tested at Guangzhou station in China with humid subtropical climate influenced by the Asian monsoon as a case study. Results show that relative humidity has a greater effect than that of seasonality on the air temperature-based models for daily global solar radiation estimation, and the models of BC family including the effects of seasonality and/or relative humidity give better estimates. Accordingly, a strategy for selecting an optimum model for estimating daily global solar radiation in the humid regions is proposed. (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 595-599, 201

    Numerical Simulation and Comparison of Conventional and Sloped Solar Chimney Power Plants: The Case for Lanzhou

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    The solar chimney power plant (SCPP) generates updraft wind through the green house effect. In this paper, the performances of two SCPP styles, that is, the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP), are compared through a numerical simulation. A simplified Computational Fluid Dynamics (CFD) model is built to predict the performances of the SCPP. The model is validated through a comparison with the reported results from the Manzanares prototype. The annual performances of the CSCPP and the SSCPP are compared by taking Lanzhou as a case study. Numerical results indicate that the SSCPP holds a higher efficiency and generates smoother power than those of the CSCPP, and the effective pressure in the SSCPP is relevant to both the chimney and the collector heights

    Performance analysis of conventional and sloped solar chimney power plants in China

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    The solar chimney power plant (SCPP) has been accepted as one of the most promising approaches for future large-scale solar energy applications. This paper reports on a heat transfer model that is used to compare the performance of a conventional solar chimney power plant (CSCPP) and two sloped solar chimney power plants (SSCPPs) with the collector oriented at 30 degrees and 60 degrees, respectively. The power generation from SCPPs at different latitudes in China is also analyzed. Results indicate that the larger solar collector angle leads to improved performance in winter but results in lower performance in summer. It is found that the optimal collector angle to achieve the maximum power in Lanzhou, China, is around 60 degrees. Main factors that influence the performance of SCPPs also include the system height and the air thermophysical characteristics. The ground energy loss, reflected solar radiation, and kinetic loss at the chimney outlet are the main energy losses in SCPPs. The studies also show SSCPPs are more suitable for high latitude regions in Northwest China, but CSCPPs are suggested to be built in southeastern and eastern parts of China with the combination to the local agriculture. (C) 2012 Elsevier Ltd. All rights reserved
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