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71.
油气二次运移的方式和方向对具体指出盆地油气资源量所赋存的位置有决定性的意义.在运载层中推动油气运动的作用力主要是浮力和毛细管力,而盖层则起着毛细管阻力作用.因此盖层的形状及空间分布就成了影响运移路径重要的封盖因素.该文试图根据盖层的几何形状特性,建立运移路径模拟模型,开发微机软件运行实施.在一个具体盆地进行运移路径模拟应用的结果反映,与已知勘探情况基本符合,能够检验油气期次性运移的地质概念,可以揭示运移过程,预测可能的运移聚集位置. 相似文献
72.
The energy planning of power sector constitutes a multifaceted challenge for policy makers, incorporating a variety of economic, technological, environmental, political and social aspects in order to ensure the unhindered equilibrium between electricity demand and electricity supply. This paper presents a deterministic bottom-up Mixed Integer Linear Programming model for the long-term energy planning of national power supply systems, having special focus and modeling effort on the peculiar case of Greece. It is a least cost optimization based model being expanded and enhanced with the integration of electric interconnections and the evident participation of environmental dimension. Its superstructure consists of multiple mathematical expressions representing power demand patterns, technical constraints, operation rules, penetration potential of energy sources, economic aspects, technological availability, environmental obligations and other sectoral targets and commitments applying in the electricity supply field. Its main contribution lies on the holistic methodological approach adopted, concerning the discrete electric systems of mainland and insular areas in Greece by proposing a novel way of simulating the potentiality of their submarine interconnection. The present model is applied on a real case study concerning the Greek electricity planning problem for the period 2014–2024, through the elaboration of two alternative evolution scenarios. The underlying objective is multifarious: (a) to deliver the portfolio of new capacity investments, the fuel mix trend, the penetration of renewable energy sources and the progress of achieving country׳s commitments and targets, and (b) to investigate and highlight the potential economic, energy and environmental benefits arising from the electrical interconnection of Greek islands to the main continental power system. 相似文献
73.
BackgroundQuercetin, one of the most well-known flavonoids, has been included in human diet for a long history. The use of quercetin has been widely associated with a great number of health benefits, including antioxidant, anti-inflammatory, antiviral and anticancer as well as the function to ease some cardiovascular diseases (i.e., heart disease, hypertension, and high blood cholesterol). However, poor water solubility, chemical instability and low bioavailability of quercetin greatly limit its applications. Utilization of delivery systems can improve its stability, efficacy and bioavailability.Scope and approachIn this review, biological activities, chemical stability, metabolism and toxicity of quercetin and different delivery systems for quercetin were discussed.Key findings and conclusionsQuercetin digested in human body (e.g., mouth, small intestine, liver, kidneys) undergoes glucuronidation, sulfation or methylation. During the food processing and storage, many factors such as heat, pH, metal ions, could affect the chemical stability (including oxidation and degradation) of quercetin. Utilization of delivery systems including lipid-based carriers, nanoparticles, inclusion complexes, micelles and conjugates-based encapsulation has the potential to improve both the stability and bioavailability and thus health benefits of quercetin. Each delivery system has its unique advantages and shortcomings, and the specific selection should be based on the application domains. Moreover, the exploration of natural food-grade ingredients as main compositions of delivery systems for quercetin might be required in the future. 相似文献
74.
Guanyu Wang 《Journal of the Royal Society Interface》2012,9(75):2723-2734
Bistability is a fundamental phenomenon in nature. In biology, a number of fine properties of bistability have been identified. However, these properties are only consequences of bistability at the physiological level, which do not explain why it had to emerge during evolution. Using optimal homeostasis as the first principle, I find that bistability emerges as an indispensable control mechanism. It is the only solution to a dilemma in glucose homeostasis: high insulin efficiency is required to confer rapidness in plasma glucose clearance, whereas an insulin sparing state is required to guarantee the brain''s safety during fasting. The optimality consideration renders a clear correspondence between the molecular and physiological levels. This new perspective can illuminate studies on the twin epidemics of obesity and diabetes and the corresponding intervening strategies. For example, overnutrition and sedentary lifestyle may represent sudden environmental changes that cause the lose of optimality, which may contribute to the marked rise of obesity and diabetes in our generation. Because this bistability result is independent of the parameters of the mathematical model (for which the result is quite general), some other biological systems may also use bistability to control homeostasis. 相似文献
75.
ObjectiveTo replicate the Dual Pathway Model (DPM) of bulimia nervosa (BN) symptoms prospectively, and to assess whether a revised version of the DPM that included the variables social comparisons made on Facebook and sociotropy influenced the DPM.MethodParticipants were 245 females who completed baseline measures (T1) that assessed the DPM, as well as the constructs social comparisons made on Facebook, and sociotropy, and a follow-up questionnaire, which assessed symptoms of depression, bulimia, and dietary restraint, one month later (T2).ResultsPath analysis revealed that the original and the revised DPMs had excellent fit once modifications to the respective models were made. In both DPMs, T1 pressures to be thin and T1 thin ideal internalization were related to T1 body dissatisfaction. T1 body dissatisfaction prospectively predicted T2 depressive symptoms and T2 bulimic symptoms, but not T2 dietary restraint. Furthermore, T2 dietary restraint, but not T2 depressive symptoms, predicted T2 BN symptoms. Results also showed that T2 dietary restraint was associated with T2 depressive symptoms. In the revised DPM, T1 social comparisons made on Facebook were associated with T1 body dissatisfaction, T1 pressures to be thin, and T2 bulimic symptoms. T1 sociotropy was related to T1 social comparisons on Facebook, T1 pressures to be thin, T1 body dissatisfaction, and T2 bulimic symptoms.ConclusionsFindings suggest the BN preventative efforts might benefit from addressing appropriate forms of social comparisons, especially those made on Facebook, and the personality trait sociotropy. 相似文献
76.
Guadalupe Aparicio Gallego Vanessa Medina Villaamil Enrique Grande Isabel Santamarina Ca��nzos Lu��s M. Ant��n Aparicio 《International journal of molecular sciences》2012,13(10):12710-12733
Historically, cell-signaling pathways have been studied as the compilation of isolated elements into a unique cascade that transmits extracellular stimuli to the tumor cell nucleus. Today, growing evidence supports the fact that intracellular drivers of tumor progression do not flow in a single linear pathway, but disseminate into multiple intracellular pathways. An improved understanding of the complexity of cancer depends on the elucidation of the underlying regulatory networks at the cellular and intercellular levels and in their temporal dimension. The high complexity of the intracellular cascades causes the complete inhibition of the growth of one tumor cell to be very unlikely, except in cases in which the so-called “oncogene addiction” is known to be a clear trigger for tumor catastrophe, such as in the case of gastrointestinal stromal tumors or chronic myeloid leukemia. In other words, the separation and isolation of the driver from the passengers is required to improve accuracy in cancer treatment. This review will summarize the signaling pathway crossroads that govern renal cell carcinoma proliferation and the emerging understanding of how these pathways facilitate tumor escape. We outline the available evidence supporting the putative links between different signaling pathways and how they may influence tumor proliferation, differentiation, apoptosis, angiogenesis, metabolism and invasiveness. The conclusion is that tumor cells may generate their own crossroads/crosstalk among signaling pathways, thereby reducing their dependence on stimulation of their physiologic pathways. 相似文献
77.
Ronghui Zhang Yubo Ma Feng You Tao Peng Zhaocheng He Kening Li 《International Journal of Hydrogen Energy》2017,42(40):25185-25194
A cheap and magnetic Ni/Cu/Al/Fe catalyst for the selective hydrogenation of LA into GVL catalysts was prepared by sol-gel method. The reaction pathway was systematically studied by examining the reaction conditions, such as reaction pressure, catalyst loadings, water content, and reaction temperature. Higher reaction pressure and catalyst loadings were prior to form HA, then MHV, finally GVL; ML was easily to form with a higher reaction temperature. Water, as a key role, which was in favor to form HA, then MHV, finally GVL; more important, a higher LA conversion could be obtained in methanol as the solvent with some certain content of water. And, it can give a reference for future new clean energy vehicles' application. 相似文献
78.
Sangmoo Choi Canek Fuentes-HernandezMinseong Yun Amir DindarTalha M. Khan Cheng-Yin WangBernard Kippelen 《Organic Electronics》2014,15(12):3780-3786
We report on a reverse stamping method to produce via-holes in circuits comprising acene-based top-gate organic field-effect transistors (OFETs) having a CYTOP/Al2O3 (by atomic layer deposition) bilayer gate dielectric. This method relies on the weak adhesive force that exists between a small molecule acene film and a polymer to enable easy delamination of the bilayer gate dielectric by using a PDMS stamp. We demonstrate the effectiveness of this method by fabricating simple circuits using top-gate triisopropylsilylethynyl pentacene (TIPS-pentacene)/poly (triarylamine) (PTAA) OFETs. 相似文献
79.
Chao Li Shaohua Dai Jiangyi Lu Baoyu Zhao Jiangang Wang Panpan Li Zhaozhen Wu Yingying Mu Cuixia Feng Qiang Dong 《Journal of dairy science》2018,101(9):8513-8523
Ketosis causes serious economic losses for the modern dairy industry because it is a highly prevalent metabolic disease among cows in high-producing herds during the transition period. Due to some striking similarities between diabetes in humans and ketosis in dairy cows, there is potential for the use of methylglyoxal (MGO)—commonly used in human diabetics—as a biomarker in dairy cattle. However, currently no data are available about the presence of MGO in the serum of dairy cattle or about the characteristics of its production or its potential contribution in the pathogenesis of ketosis. To determine the potential origin and pathway of formation of MGO, cows in different metabolic conditions [i.e., non-subclinically ketotic dairy cows in early lactation (n = 7), subclinically ketotic dairy cows in early lactation (n = 8), overconditioned dry cows (BCS >4.25, n = 6), and nonlactating heifers (n = 6)] were selected. Serum MGO concentrations were determined and correlated with indicators of the glucose and lipid metabolism and with haptoglobin (Hp) as an inflammatory marker. The serum MGO concentrations in subclinically ketotic cows (712.60 ± 278.77 nmol/L) were significantly greater than in nonlactating heifers (113.35 ± 38.90 nmol/L), overconditioned dry cows (259.71 ± 117.97 nmol/L), and non-subclinically ketotic cows (347.83 ± 63.56 nmol/L). In serum of lactating cows, concentrations of glucose and fructosamine were lower than in heifers and were negatively correlated with MGO concentrations. Even so, concentrations of metabolic and inflammatory markers such as dihydroxyacetone phosphate, nonesterified fatty acids, β-hydroxybutyrate, acetone, and Hp were remarkably higher in subclinically ketotic cows compared with nonlactating heifers; these metabolites were also positively correlated with MGO. In human diabetics elevated MGO concentrations are stated to originate from both hyperglycemia and the enhanced lipid metabolism, whereas higher MGO concentrations in subclinically ketotic cows were not associated with hyperglycemia. Therefore, our data suggest MGO in dairy cows to be a metabolite produced from the metabolization of acetone within the lipid metabolization pathway and from the metabolization of dihydroxyacetone phosphate. Furthermore, the highly positive correlation between MGO and Hp suggests that this reactive compound might be involved in the proinflammatory state of subclinical ketosis in dairy cows. However, more research is needed to determine the potential use of MGO as a biomarker for metabolic failure in dairy cows. 相似文献
80.