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排序方式: 共有335条查询结果,搜索用时 15 毫秒
1.
Raquel Cano Jos L. Prez Liss Angarita Dvila ngel Ortega Yosselin Gmez Nereida Josefina Valero-Cedeo Heliana Parra Alexander Manzano Teresa Isabel Vliz Castro María P. Díaz Albornoz Gabriel Cano Joselyn Rojas-Quintero Maricarmen Chacín Valmore Bermúdez 《International journal of molecular sciences》2021,22(9)
Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disorder, affecting around 25% of the population worldwide. It is a complex disease spectrum, closely linked with other conditions such as obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome, which may increase liver-related mortality. In light of this, numerous efforts have been carried out in recent years in order to clarify its pathogenesis and create new prevention strategies. Currently, the essential role of environmental pollutants in NAFLD development is recognized. Particularly, endocrine-disrupting chemicals (EDCs) have a notable influence. EDCs can be classified as natural (phytoestrogens, genistein, and coumestrol) or synthetic, and the latter ones can be further subdivided into industrial (dioxins, polychlorinated biphenyls, and alkylphenols), agricultural (pesticides, insecticides, herbicides, and fungicides), residential (phthalates, polybrominated biphenyls, and bisphenol A), and pharmaceutical (parabens). Several experimental models have proposed a mechanism involving this group of substances with the disruption of hepatic metabolism, which promotes NAFLD. These include an imbalance between lipid influx/efflux in the liver, mitochondrial dysfunction, liver inflammation, and epigenetic reprogramming. It can be concluded that exposure to EDCs might play a crucial role in NAFLD initiation and evolution. However, further investigations supporting these effects in humans are required. 相似文献
2.
Speciation of the semivolatile hydrocarbon engine emissions from sunflower biodiesel 总被引:1,自引:0,他引:1
Biodiesel fuel is a very attractive alternative to conventional fuel and its effects in the engine performance and regulated emissions have been widely studied. However, the impact on unregulated individual compounds or chemical characteristics of exhaust emissions is not fully characterized. In this paper, the semivolatile fractions of the exhaust emissions of biodiesel blends and conventional fuel have been speciated. The results show great differences between the compounds emitted, especially regarding oxygenated and aromatic species. Likewise, there is a clear relationship between speciated hydrocarbons and other important emissions such as total hydrocarbons (HC), particulate matter (PM), volatile organic fraction (VOF) and mean particle diameter (Dm) of PM. 相似文献
3.
Effect of the exposure angle in the corrosion rate of plain carbon steel in a marine atmosphere 总被引:1,自引:0,他引:1
This investigation aims to analyse the effect of the exposure angle on the corrosion rate of mild steel. Test samples were exposed to a marine environment at 0°, 30°, 45° and 90° inclination. To determine the effects of contaminants on the protective characteristics of the rusts, Cl and SO2 contents in the atmosphere as well as SEM-EDX analyses and polarisation curves on the weathered samples were performed. Results demonstrated that the exposure angle influences the corrosion rate, as also the morphology of the rust, but with no effect on rust composition. 相似文献
4.
Organizations that respond to disasters hold unreasonable standards for data arising from technology-enabled citizen contributions. This has strong negative potential for the ability of these responding organizations to incorporate these data into appropriate decision points. We argue that the landscape of the use of social media data in crisis response is varied, with pockets of use and acceptance among organizations. In this paper we present findings from interviews conducted with representatives from large international disaster response organizations concerning their use of social media data in crisis response. We found that emergency responders already operate with less than reliable, or “good enough,” information in offline practice, and that social media data are useful to responders, but only in specific crisis situations. Also, responders do use social media, but only within their known community and extended network. This shows that trust first begins with people and not data. Lastly, we demonstrate the barriers used by responding organizations have gone beyond discussions of trustworthiness and data quality to that of more operational issues. 相似文献
5.
Maria del Rosario Martínez-Macias Rocio Janeth Aguilar-Ruiz Omar Nateras-Ramírez Dalia Isabel Sánchez-Machado Jaime López-Cervantes Germán Eduardo Dévora-Isiordia Jesús Álvarez-Sánchez Nidia Josefina Ríos-Vázquez 《Journal of the American Oil Chemists' Society》2021,98(10):993-1000
Greenhouse gases emitted into the atmosphere by burning of fossil fuels cause global warming. One option is obtaining biodiesel. Nannochloropsis oculata was cultured under different light intensities and reactors at 25°C for 21 days with f/2 medium to assess their effects on cell density, lipid, and fatty acids (FAs). N. oculata improved cell density on fed-batch glass tubular reactor (7 L) at 200 μmol E m−2 s−1, yielding 3.5 × 108 cells ml−1, followed by fed-batch Erlenmeyer flask (1 L) at 650 μmol E m−2 s−1 with 1.7 × 108 cells ml−1. The highest total lipid contents (% g lipid × g dry biomass−1) were 44.4 ± 0.8% for the reactor (1 L) at 650 μmol E m−2 s−1 and 35.2 ± 0.2% for the tubular reactor (7 L) at 200 μmol E m−2 s−1, until twice as high compared with the control culture (Erlenmeyer flask 1 L, 80 μmol E m−2 s−1) with 21.2 ± 1%. Comparing the total lipid content at 200 μmol E m−2 s−1, tubular reactor (7 L) and reactor 1 L achieved 35.2 ± 0.2% and 28.3 ± 1%, respectively, indicating the effect of shape reactor. The FAs were affected by high light intensity, decreasing SFAs to 2.5%, and increased monounsaturated fatty acids + polyunsaturated fatty acids to 2.5%. PUFAs (20:5n-3) and (20:4n-3) were affected by reactor shape, decreasing by half in the tubular reactor. In the best culture, fed-batch tubular reactor (7 L) at 200 μmol E m−2 s−1 contains major FAs (16:0; 38.06 ± 0.16%), (16:1n-7; 30.74 ± 0.58%), and (18:1n-9; 17.15 ± 0.91%). 相似文献
6.
Juan Manuel González Calleros Josefina Guerrero García Jean Vanderdonckt 《Universal Access in the Information Society》2013,12(4):387-401
The need for accessibility evaluation tools is motivated by several endogenous and exogenous reasons coming from the end user (the designer and the developer) and companies releasing information systems. Existing evaluation tools mainly concentrate on examining the code of Web pages: Web pages more and more frequently contain non-HTML parts that entirely escape from being treated by existing techniques. This is the case of the advanced human–machine interface (AHMI), a piece of software programmed in C/C++, used for controlling the advanced flight management system in the aircraft cockpit. Studying this new user interface (UI) requires a structured approach to evaluate and validate AHMI designs. The goal in this work is to develop an evaluation tool to automate the process of evaluating the AHMI. The method addresses: support of multiple bases of guidelines (accessibility or usability or both) on-demand (partial or total evaluation), with different levels of details (a presentation for developers and for those responsible for certifying accessibility). The method goes a step toward the automatic evaluation of UI containing non-HTML parts. 相似文献
7.
JA Tapia Granados 《Canadian Metallurgical Quarterly》1998,3(3):137-151
During the last few decades, traffic injuries have become one of the leading causes of death and disability in the world. In urban areas, traffic congestion, noise, and emissions from motor vehicles produce subjective disturbances and detectable pathological effects. More than one billion people are exposed to harmful levels of environmental pollution. Because its combustion engine generates carbon dioxide (CO2), the automobile is one of the chief sources of the gases that are causing the greenhouse effect. The latter has already caused a rise in the average ambient temperature, and over the next decades it will predictable cause significant climatic changes whose consequences, though uncertain, are likely to be harmful and possibly catastrophic. Aside from the greenhouse effect, the relentless growth of parking zones, traffic, and the roadway infrastructure in urban and rural areas is currently one of the leading causes of environmental degradation. Urban development, which is nearly always "planned" around traffic instead of people, leads to a significant deterioration in the quality of life, while it also destroys the social fabric. Unlike the private automobile, public transportation, bicycles, and walking help reduce pollution, congestion, and traffic volume, as well as the morbidity and mortality resulting from injuries and ailments related to pollution. Non-automobile transportation also encourages physical activity--with its positive effect on general health--and helps reduce the greenhouse effect. The drop in traffic volume and the increased use of alternate means of transportation are thus an integrated health promotion policy which should become an inherent part of the movement for the promotion of healthy cities and of transportation policies and economic policy in general. 相似文献
8.
J.M. Tapia Garcı´a M.J. del Moral M.A. Martínez E. Herrera-Viedma 《Expert systems with applications》2012,39(11):10022-10030
Sometimes, we find decision situations in which it is difficult to express some preferences by means of concrete preference degrees. In this paper, we present a consensus model for group decision making problems in which the experts use linguistic interval fuzzy preference relations to represent their preferences. This model is based on two consensus criteria, a consensus measure and a proximity measure, and on the concept of coincidence among preferences. We compute both consensus criteria in the three representation levels of a preference relation and design an automatic feedback mechanism to guide experts in the consensus reaching process. 相似文献
9.
Josefina Sierra-Santibáñez 《Annals of Mathematics and Artificial Intelligence》2003,39(1-2):61-100
We study the declarative formalization of reasoning strategies by presenting declarative formalizations of: (1) the SNLP algorithm for nonlinear planning, and (2) a particular algorithm for blocks world nonlinear planning proposed in this paper. The formal models of a heuristic forward chaining planner, which can take advantage of declarative formalizations of action selection strategies, and of a reasoning strategy based planner, which can use declarative formalizations of reasoning strategies, are proposed. The effectiveness of these systems is studied from formal and empirical points of view. Empirical results showing how the use of declarative formalizations of reasoning strategies can reduce the amount of search required for solving planning problems (with respect to state of the art planning systems) are presented. 相似文献
10.