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排序方式: 共有1434条查询结果,搜索用时 109 毫秒
51.
Christina Plati Panos Georgiou Vasilis Papavasiliou 《Structure and Infrastructure Engineering》2016,12(9):1127-1136
This article aims to investigate the feasibility of incorporating of an artificial neural network (ANN) as an innovative technique for modelling the pavement structural condition, into pavement management systems. For the development of the ANN, strain assessment criteria are set in order to characterise the structural condition of flexible asphalt pavements with regards to fatigue failure. This initial task is directly followed with the development of an ANN model for the prediction of strains primarily based on in situ field gathered data and not through the usage of synthetic databases. For this purpose, falling weight deflectometer (FWD) measurements were systematically conducted on a highway network, with ground-penetrating radar providing the required pavement thickness data. The FWD data (i.e. deflections) were back-analysed in order to assess strains that would be utilised as output data in the process of developing the ANN model. A paper exercise demonstrates how the developed ANN model combined with the suggested conceptual approach for characterising pavement structural condition with regard to strain assessment could make provisions for pavement management activities, categorising network pavement sections according to the need for maintenance or rehabilitation. Preliminary results indicate that the ANN technique could help assist policy decision makers in deriving optimum strategies for the planning of pavement infrastructure maintenance. 相似文献
52.
Koji Kamagata Christina Andica Ayumi Kato Yuya Saito Wataru Uchida Taku Hatano Matthew Lukies Takashi Ogawa Haruka Takeshige-Amano Toshiaki Akashi Akifumi Hagiwara Shohei Fujita Shigeki Aoki 《International journal of molecular sciences》2021,22(10)
There has been an increasing prevalence of neurodegenerative diseases with the rapid increase in aging societies worldwide. Biomarkers that can be used to detect pathological changes before the development of severe neuronal loss and consequently facilitate early intervention with disease-modifying therapeutic modalities are therefore urgently needed. Diffusion magnetic resonance imaging (MRI) is a promising tool that can be used to infer microstructural characteristics of the brain, such as microstructural integrity and complexity, as well as axonal density, order, and myelination, through the utilization of water molecules that are diffused within the tissue, with displacement at the micron scale. Diffusion tensor imaging is the most commonly used diffusion MRI technique to assess the pathophysiology of neurodegenerative diseases. However, diffusion tensor imaging has several limitations, and new technologies, including neurite orientation dispersion and density imaging, diffusion kurtosis imaging, and free-water imaging, have been recently developed as approaches to overcome these constraints. This review provides an overview of these technologies and their potential as biomarkers for the early diagnosis and disease progression of major neurodegenerative diseases. 相似文献
53.
In the present work, the derivation of two surrogate models (SMs) for modelling the flow around a propeller for small aircrafts is presented. Both methodologies use derived functions based on computations with the detailed propeller geometry. The computations were performed using k–ω shear stress transport for modelling turbulence. In the SMs, the modelling of the propeller was performed in a computational domain of disk-like geometry, where source terms were introduced in the momentum equations. In the first SM, the source terms were polynomial functions of swirl and thrust, mainly related to the propeller radius. In the second SM, regression analysis was used to correlate the source terms with the velocity distribution through the propeller. The proposed SMs achieved faster convergence, in relation to the detail model, by providing also results closer to the available operational data. The regression-based model was the most accurate and required less computational time for convergence. 相似文献
54.
p‐type TCOs for use in transparent electronics In this article, a new type of semiconducting material is introduced. Transparent conducting thin films are already established in our everydaylife. But the type of these so‐called ?TCOs”? is dominated by electron transport, that means they are n‐type. To get transparent p‐n‐junctions and therefore transparent electronics, the missing part is a transparent p‐type material. Researchers all over the world have found different approach to produce this new generation of materials. At the Fraunhofer Institute for Surface Engineering and Thin Films (IST) in Braunschweig it is now possible to produce these kind of thin films as well. 相似文献
55.
Christina Kopp Afshin Hosseini Shiva P. Singh Petra Regenhard Hamed Khalilvandi-Behroozyar Helga Sauerwein Manfred Mielenz 《International journal of molecular sciences》2014,15(11):21401-21418
The transition period in dairy cows (3 weeks prepartum until 3 weeks postpartum) is associated with substantial mobilization of energy stores, which is often associated with metabolic diseases. Nicotinic acid (NA) is an antilipolytic and lipid-lowering compound used to treat dyslipidaemia in humans, and it also reduces non-esterified fatty acids in cattle. In mice the G-protein coupled receptor 109A (GPR109A) ligand NA positively affects the secretion of adiponectin, an important modulator of glucose and fat metabolism. In cattle, the corresponding data linking NA to adiponectin are missing. Our objective was to examine the effects of NA on adiponectin and AMPK protein abundance and the expression of mRNAs of related genes such as chemerin, an adipokine that enhances adiponectin secretion in vitro. Differentiated bovine adipocytes were incubated with pertussis toxin (PTX) to verify the involvement of GPR signaling, and treated with 10 or 15 µM NA for 12 or 24 h. NA increased adiponectin concentrations (p ≤ 0.001) and the mRNA abundances of GPR109A (p ≤ 0.05) and chemerin (p ≤ 0.01). Pre-incubation with PTX reduced the adiponectin response to NA (p ≤ 0.001). The NA-stimulated secretion of adiponectin and the mRNA expression of chemerin in the bovine adipocytes were suggestive of GPR signaling-dependent improved insulin sensitivity and/or adipocyte metabolism in dairy cows. 相似文献
56.
Edward W.N. Bernroider Christina W.Y. Wong Kee-hung Lai 《International Journal of Project Management》2014
This study explores whether an Enterprise Resource Planning (ERP) implementation project mediates the relationship between dynamic pre-adoption capabilities and ERP-enabled business improvements. The results from our field survey of large ERP adopters in Austria suggest that the effects of the two out of three selected dynamic capabilities are dependent on the properties of the underlying organizational transformation project. While external information acquisition and IT governance capabilities are fully mediated by the performance of the ERP implementation project, decision making only directly impacts business capabilities. These results further our understanding about the role of the implementation project for ERP value creation and the different natures of capability relationships. We call for more research on co-presence conditions related to dynamic capabilities and IT transformation project performance. 相似文献
57.
Katja Buhr Christina Pammer Peter Schieberle 《European Food Research and Technology》2010,230(3):375-381
Completeness of extraction, losses during isolation and, in particular, the formation of new constituents are challenges during
the enrichment of volatiles for GC analysis. Especially the isolation of volatiles by simultaneous steam distillation/extraction
has long been known to generate artifacts due to the hot water treatment. However, even a simple treatment of dry foods with
cold water may already lead to the release of odour-active volatiles. After treatment of chocolate or cocoa beans with water,
the concentrations of the four Strecker aldehydes 2- and 3-methylbutanal, 3-(methylthio)propanal and phenylacetaldehyde were
increased by factors between 10 and 100. Also in other dry processed foods, such as malt or crackers, the concentrations of
the Strecker aldehydes were substantially increased upon water addition. Although a physical release of the aldehydes weakly
bound to, e.g. proteins or starch is possible, in a further experiment, it could be shown that a yet unknown precursor of
3-(methylthio)propanal and phenylacetaldehyde could be isolated by solvent extraction from caramalt and Munich malt. As a
consequence, the presence or absence of water during the work-up procedure might either lead to an over- or underestimation
of the relevance of the respective aroma compounds, which might also effect aroma formation and perception during the process
of eating. 相似文献
58.
Christina M.R. Kitchen Jing Kroll Erik Bloomquist Marc A. Suchard 《Computational statistics & data analysis》2009,53(3):766-775
Enfuvirtide (ENF) is a fusion inhibitor that prevents the entry of HIV virions into target cells. Studying the characteristics of viral evolution during treatment and after a treatment interruption can lend insight into the mechanisms of viral evolution and fitness. Although interruption of anti-HIV therapy often results in rapid emergence of an archived “wild-type” virus population, previous work from our group indicates that when only ENF is interrupted, viral gp41 continues to evolve forward and resistance mutations are lost due to back-mutation and remodeling of the envelope protein. To examine the co-evolution of gp120 and gp41 during ENF interruption we extend the Bayesian Hierarchical Phylogenetic model (HPM). Current HPMs enforce conditional independence across all outcomes while biologically all gene regions within a patient should return the same tree unless recombination confers an evolutionary selective advantage. A two-way-interaction HPM is proposed that provides middle ground between these two extremes and allows us to test for differences in evolutionary pressures across gene regions in multiple patients simultaneously. When the model is applied to a well-characterized cohort of HIV-infected patients interrupting ENF we find that across patients, the virus continued to evolve forward in both gene regions. Overall, the hypothesis of independence over dependence between the gene regions is supported. Models that allow for the examination of co-evolution over time will be increasingly important as more therapeutic classes are developed, each of which may impact other through novel and complex mechanisms. 相似文献
59.
Sanghee Lee Theresa R. Mendoza Danielle N. Burner Michelle T. Muldong Christina C. N. Wu Catalina Arreola-Villanueva Abril Zuniga Olga Greenburg William Y. Zhu Jamillah Murtadha Evodie Koutouan Naomi Pineda Hao Pham Sung-Gu Kang Hyun Tae Kim Gabriel Pineda Kathleen M. Lennon Nicholas A. Cacalano Catriona H. M. Jamieson Christopher J. Kane Anna A. Kulidjian Terry Gaasterland Christina A. M. Jamieson 《International journal of molecular sciences》2022,23(6)
60.
Christina Jane Vellan Jaime Jacqueline Jayapalan Boon-Koon Yoong Azlina Abdul-Aziz Sarni Mat-Junit Perumal Subramanian 《International journal of molecular sciences》2022,23(4)
Pancreatic ductal adenocarcinoma (PDAC), a highly aggressive malignancy with a poor prognosis is usually detected at the advanced stage of the disease. The only US Food and Drug Administration-approved biomarker that is available for PDAC, CA 19-9, is most useful in monitoring treatment response among PDAC patients rather than for early detection. Moreover, when CA 19-9 is solely used for diagnostic purposes, it has only a recorded sensitivity of 79% and specificity of 82% in symptomatic individuals. Therefore, there is an urgent need to identify reliable biomarkers for diagnosis (specifically for the early diagnosis), ascertain prognosis as well as to monitor treatment response and tumour recurrence of PDAC. In recent years, proteomic technologies are growing exponentially at an accelerated rate for a wide range of applications in cancer research. In this review, we discussed the current status of biomarker research for PDAC using various proteomic technologies. This review will explore the potential perspective for understanding and identifying the unique alterations in protein expressions that could prove beneficial in discovering new robust biomarkers to detect PDAC at an early stage, ascertain prognosis of patients with the disease in addition to monitoring treatment response and tumour recurrence of patients. 相似文献