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排序方式: 共有136条查询结果,搜索用时 31 毫秒
1.
John J. Guardiola Josiah E. Hardesty Juliane I. Beier Russell A. Prough Craig J. McClain Matthew C. Cave 《International journal of molecular sciences》2021,22(10)
Background: High-level occupational vinyl chloride (VC) exposures have been associated with hepatic hemangiosarcoma, which typically develops following a long latency period. Although VC is genotoxic, a more comprehensive mode of action has not been determined and diagnostic biomarkers have not been established. The purpose of this study is to address these knowledge gaps through plasma metabolomics. Methods: Plasma samples from polyvinyl chloride polymerization workers who developed hemangiosarcoma (cases, n = 15) and VC exposure-matched controls (n = 17) underwent metabolomic analysis. Random forest and bioinformatic analyses were performed. Results: Cases and controls had similar demographics and routine liver biochemistries. Mass spectroscopy identified 606 known metabolites. Random forest analysis had an 82% predictive accuracy for group classification. 60 metabolites were significantly increased and 44 were decreased vs. controls. Taurocholate, bradykinin and fibrin degradation product 2 were up-regulated by greater than 80-fold. The naturally occurring anti-angiogenic phenol, 4-hydroxybenzyl alcohol, was down-regulated 5-fold. Top affected ontologies involved: (i) metabolism of bile acids, taurine, cholesterol, fatty acids and amino acids; (ii) inflammation and oxidative stress; and (iii) nicotinic cholinergic signaling. Conclusions: The plasma metabolome was differentially regulated in polyvinyl chloride workers who developed hepatic hemangiosarcoma. Ontologies potentially involved in hemangiosarcoma pathogenesis and candidate biomarkers were identified. 相似文献
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3.
Jesú s Guardiola Soler Juan J. Prieto Marqu s M nica Garcí a Ruiz Guadalupe Ramos Caicedo 《Chemical Engineering Communications》2003,190(3):285-298
The purpose of the present work is to demonstrate the reliability of a digital image processing technique. A CCD (Charge Coupled Device) is used to perform an investigation on the bubble properties of a 2D gas-solid fluidized bed, and the aim of this study is to establish a criterion in order to reject all images that could not be interpreted as bubbles. This may lead to an alteration of the information obtained. The two-dimensional fluidized bed is 20 cm wide and at least 20 cm high, and the field of view of the camera is 12.54 cm wide and 12.99 cm high. In this way, bubbles could be totally or partially placed into this field of view so that a partial image of a bubble could be analyzed as a whole bubble. With this calibration, a geometric decision criterion for the rejection of nonbubble images was developed. 相似文献
4.
Gorka Epelde Eduardo Carrasco Gottfried Zimmermann Jan Alexandersson Robert Neßelrath Markus Dubielzig 《Universal Access in the Information Society》2013,12(1):73-87
This paper presents a new approach to make current and future television universally accessible. The proposed approach provides a means of universal accessibility both for remotely operating the TV set and for interacting with online services delivered through the TV. This proposal is based on the ISO/IEC 24752 “Universal Remote Console” (URC) standard. This standard defines an abstract user interface layer called the “user interface socket” and allows the development of pluggable (plug-in) user interfaces for any type of user and any control device. The proposed approach lays the foundation for the development of advanced user interfaces that can be interacted within various modalities. Different prototypes have been developed based on this approach and tested with end users. The user tests have shown this approach to be a viable option for the proposed scenarios. Based on the experience gathered with the prototypes, recommendations and implementation options are suggested for commercial adoption. 相似文献
5.
A new method for robust fixed-order H∞ controller design by convex optimization for multivariable systems is investigated. Linear Time-Invariant Multi-Input Multi-Output (LTI-MIMO) systems represented by a set of complex values in the frequency domain are considered. It is shown that the Generalized Nyquist Stability criterion can be approximated by a set of convex constraints with respect to the parameters of a multivariable linearly parameterized controller in the Nyquist diagram. The diagonal elements of the controller are tuned to satisfy the desired performances, while simultaneously, the off-diagonal elements are designed to decouple the system. Multimodel uncertainty can be directly considered in the proposed approach by increasing the number of constraints. The simulation examples illustrate the effectiveness of the proposed approach. 相似文献
6.
Analysis of scenarios for the reduction of energy consumption and GHG emissions in transport in the Basque Country 总被引:1,自引:0,他引:1
Gorka Bueno 《Renewable & Sustainable Energy Reviews》2012,16(4):1988-1998
Fossil energy depletion and fight against climate change force humanity to decarbonize the economy. By year 2050 CO2 emissions will have to reduce globally at least 85%, and probably over 95% in developed countries.The modeling of the transportation of people and commodities in the Basque Autonomous Community (Spain) in year 2008 has allowed us to draw some conclusions about the challenges ahead. The exploration of several scenarios modeled in order to reduce energy consumption in transport shows that mobility in a decarbonized world will have to be more efficient, electrified when moving people and freight on land, based on renewable generation, and organized in such a way that guarantees very high occupancies of vehicles. All these elements will be indispensable, and even not sufficient if they are still not complemented with a reduction of mobility in absolute terms, so that economic transportation intensity—the ratio between transportation and whole economic activity—recovers to levels seen in the world four decades ago, prior to the development of present hypermobility. 相似文献
7.
Local governments are responsible for the supply of important public services in cities. On many occasions the management of those services is externalized. There is extensive literature analyzing the explanations for the governance option taken by local governments, aiming to ascertain the reasons why the management of certain services is externalized. Recent research has highlighted the fact that time has not been contemplated by research dealing with explanatory factors in the decision to contract out municipal services. This is a key issue in order to identify the real reason behind policymakers’ decisions about the management of the services in cities. This paper tests the importance of taking into account time in the research into contracting out. This is undertaken by means of two methodological tests in the design of variables from a dataset containing 744 municipalities in Southern Spain. Using this empirical analysis as a basis, it is concluded that considering time contributes towards enhancing the specification of the model and that omitting this aspect could lead to misunderstanding the motivation behind such decisions. 相似文献
8.
In this paper we report on homoepitaxial growth of thin Si films at substrate temperatures Ts = 500-650 °C under non-ultra-high vacuum conditions by using electron beam evaporation. Si films were grown at high deposition rates on monocrystalline Si wafers with (100), (110) and (111) orientations. The ultra-violet visible reflectance spectra of the films show a dependence on Ts and on the substrate orientation. To determine the structural quality of the films in more detail Secco etch experiments were carried out. No etch pits were found on the films grown on (100) oriented wafers. However, on films grown on (110) and (111) oriented wafers different types of etch pits could be detected. Films were also grown on polycrystalline silicon (poly-Si) seed layers prepared by an Aluminum-Induced Crystallisation (AIC) process on glass substrates. Electron Backscattering Diffraction (EBSD) shows that the film growth proceeds epitaxially on the grains of the seed layer. But a considerably higher density of extended defects is revealed by Secco etch experiments. 相似文献
9.
C. Guardiola B. Pla D. Blanco-Rodriguez L. Eriksson 《Control Engineering Practice》2013,21(11):1455-1468
Nox estimation in diesel engines is an up-to-date problem but still some issues need to be solved. Raw sensor signals are not fast enough for real-time use while control-oriented models suffer from drift and aging. A control-oriented gray box model based on engine maps and calibrated off-line is used as benchmark model for Nox estimation. Calibration effort is important and engine data-dependent. This motivates the use of adaptive look-up tables. In addition to, look-up tables are often used in automotive control systems and there is a need for systematic methods that can estimate or update them on-line. For that purpose, Kalman filter (KF) based methods are explored as having the interesting property of tracking estimation error in a covariance matrix. Nevertheless, when coping with large systems, the computational burden is high, in terms of time and memory, compromising its implementation in commercial electronic control units. However look-up table estimation has a structure, that is here exploited to develop a memory and computationally efficient approximation to the KF, named Simplified Kalman filter (SKF). Convergence and robustness is evaluated in simulation and compared to both a full KF and a minimal steady-state version, that neglects the variance information. SKF is used for the online calibration of an adaptive model for Nox estimation in dynamic engine cycles. Prediction results are compared with the ones of the benchmark model and of the other methods. Furthermore, actual online estimation of Nox is solved by means of the proposed adaptive structure. Results on dynamic tests with a diesel engine and the computational study demonstrate the feasibility and capabilities of the method for an implementation in engine control units. 相似文献
10.
Monitoring of drilling for burr detection using spindle torque 总被引:2,自引:0,他引:2
Begoa Pea Gorka Aramendi Asuncin Rivero Luis N. Lpez de Lacalle 《International Journal of Machine Tools and Manufacture》2005,45(14):1614-1621
This work proposes and evaluates a monitoring method, based on internal signals from spindle torque, to detect non-desired burr formation during drilling operations. Five features of this signal showed to be related to burr height. The selected features were sensitive to the exit burr while comparatively insensitive to changes in process parameters. The experiments were performed in aeronautics aluminium, Al 7075-T6, under dry high speed conditions. A thresholding algorithm has been developed to distinguish if burr height is below or above a previously established onset. The predictability of the developed algorithm is above 92% for the tested range of process parameters. An appropriate implementation of this monitoring system can be used as an effective quality control of drilling operations. 相似文献