259 research outputs found
On the heating environment in street canyon
This study investigates the impact of building aspect ratio (building-height-to-street-canyon-width-ratio), wind speed and surface and air-temperature difference (Δθs-a) on the heating environment within street canyon. The Reynolds-averaged Navier-Stokes (RANS) and energy transport equations were solved with Renormalization group (RNG) theory version of k-turbulence model. The validation process demonstrated that the model could be trusted for simulating air-temperature and velocity trends. The temperature and velocity patterns were discussed in idealized street canyons of different aspect ratios (0.5-2.0) with varying ambient wind speeds (0.5-1.5 m/s) and Δθs-a (2-8 K). Results show that air-temperatures are directly proportional to bulk Richardson number (Rb) for all but ground heating situation. Conversely, air-temperatures increase significantly across the street canyon with a decrease in ambient wind speed; however, the impact of Δθs-a was negligible. Clearly, ambient wind speed decreases significantly as it passes over higher AR street canyons. Notably, air-temperatures were the highest when the windward wall was heated and the least during ground heating. Conversely, air-temperatures were lower along the windward side but higher within the street canyon when the windward wall was heated. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201
Protecting eyewitness evidence: Examining the efficacy of a self-administered interview tool
Given the crucial role of eyewitness evidence, statements should be obtained as soon as possible after an incident. This is not always achieved due to demands on police resources. Two studies trace the development of a new tool, the Self-Administered Interview (SAI), designed to elicit a comprehensive initial statement. In Study 1, SAI participants reported more correct details than participants who provided a free recall account, and performed at the same level as participants given a Cognitive Interview. In Study 2, participants viewed a simulated crime and half recorded their statement using the SAI. After a delay of 1 week, all participants completed a free recall test. SAI participants recalled more correct details in the delayed recall task than control participants
Comparison of the clinical and economic outcomes between open and minimally invasive appendectomy and colectomy: evidence from a large commercial payer database
Background: Appendectomy and colectomy are commonly performed surgical procedures. Despite evidence demonstrating advantages with the minimally invasive surgical (MIS) approach, open procedures occur with greater prevalence. Therefore, there is still controversy as to whether the MIS approach is safer or more cost effective. Methods: A retrospective analysis was performed using a large commercial payer database. The data included information on 7,532 appendectomies and 2,745 colectomies. Data on the distribution of patient demographic and comorbidity characteristics associated with the MIS and open approaches were reviewed. The corresponding complication rates and expenditures were analyzed. Summary statistics were compared using chi-square tests, and generalized linear models were constructed to estimate expenditures while controlling for patient characteristics. Results: The patients undergoing MIS and open colectomy showed no significant variations in age distribution or marginal age differences for appendectomy. Significantly more patients experienced an infection postoperatively, and procedure-specific complications were more common in the open group for both procedures (P < 0.05). The postsurgical hospital stay was longer for the patients treated using the open techniques, differing an average of half a day for appendectomies and significantly more (4 days) for colectomy (P < 0.05). Readmission rates differed little between the two approaches. Procedures performed through an MIS approach were associated with lower expenditures than for the open technique, with differences ranging from 15,200 for colectomy patients (P < 0.05). Conclusions: Minimally invasive appendectomy and colectomy were associated with lower infection rates, fewer complications, shorter hospital stays, and lower expenditures than open surgery
Urban Heat Island monitoring with Global Navigation Satellite System (GNSS) data
The Urban Heat Island (UHI) effect occurs when the temperature in an urban area is higher than the temperature at a rural area. UHIs are monitored using remote sensing techniques such as satellite imagery or using temperature sensors de-ployed in a metropolitan area. In this chapter we propose a methodology to moni-tor the UHI intensity from Global Navigation Satellite Systems (GNSS) data. As the GNSS signal travels from the satellite to the receiver it propagates through the troposphere. A delay (Tropospheric delay) affects the signal. The delay is propor-tional to environmental variables. Also, the tropospheric delay in zenith direction (ZTD) is estimated as part of the Precise Point Positioning (PPP) technique. Therefore, in this chapter it is shown how to use process GNSS data to obtain ZTD and obtain temperature at an urban and a rural site simultaneously from the ZTD. The advantages of using GNSS data is its availability and many GNSS networks have been deployed in different cities so no need to deploy sensor net-works. Furthermore, GNSS signal is less affected by bad weather conditions than satellite imagery
Tetradecylthioacetic Acid Increases Hepatic Mitochondrial β-Oxidation and Alters Fatty Acid Composition in a Mouse Model of Chronic Inflammation
The administration of tetradecylthioacetic acid (TTA), a hypolipidemic and anti-inflammatory modified bioactive fatty acid, has in several experiments based on high fat diets been shown to improve lipid transport and utilization. It was suggested that increased mitochondrial and peroxisomal fatty acid oxidation in the liver of Wistar rats results in reduced plasma triacylglycerol (TAG) levels. Here we assessed the potential of TTA to prevent tumor necrosis factor (TNF) α-induced lipid modifications in human TNFα (hTNFα) transgenic mice. These mice are characterized by reduced β-oxidation and changed fatty acid composition in the liver. The effect of dietary treatment with TTA on persistent, low-grade hTNFα overexpression in mice showed a beneficial effect through decreasing TAG plasma concentrations and positively affecting saturated and monounsaturated fatty acid proportions in the liver, leading to an increased anti-inflammatory fatty acid index in this group. We also observed an increase of mitochondrial β-oxidation in the livers of TTA treated mice. Concomitantly, there were enhanced plasma levels of carnitine, acetyl carnitine, propionyl carnitine, and octanoyl carnitine, no changed levels in trimethyllysine and palmitoyl carnitine, and a decreased level of the precursor for carnitine, called γ-butyrobetaine. Nevertheless, TTA administration led to increased hepatic TAG levels that warrant further investigations to ascertain that TTA may be a promising candidate for use in the amelioration of inflammatory disorders characterized by changed lipid metabolism due to raised TNFα levels
Bcl-2 protein family: Implications in vascular apoptosis and atherosclerosis
Apoptosis has been recognized as a central component in the pathogenesis of atherosclerosis, in addition to the other human pathologies such as cancer and diabetes. The pathophysiology of atherosclerosis is complex, involving both apoptosis and proliferation at different phases of its progression. Oxidative modification of lipids and inflammation differentially regulate the apoptotic and proliferative responses of vascular cells during progression of the atherosclerotic lesion. Bcl-2 proteins act as the major regulators of extrinsic and intrinsic apoptosis signalling pathways and more recently it has become evident that they mediate the apoptotic response of vascular cells in response to oxidation and inflammation either in a provocative or an inhibitory mode of action. Here we address Bcl-2 proteins as major therapeutic targets for the treatment of atherosclerosis and underscore the need for the novel preventive and therapeutic interventions against atherosclerosis, which should be designed in the light of molecular mechanisms regulating apoptosis of vascular cells in atherosclerotic lesions
Impact and Flexural Strength, and Fracture Morphology of Acrylic Resins With Impact Modifiers
Serum Activity of Platelet-Activating Factor Acetylhydrolase Is a Potential Clinical Marker for Leptospirosis Pulmonary Hemorrhage
Pulmonary hemorrhage has been recognized as a major, often lethal, manifestation of severe leptospirosis albeit the pathogenesis remains unclear. The Leptospira interrogans virulent serogroup Icterohaemorrhagiae serovar Lai encodes a protein (LA2144), which exhibited the platelet-activating factor acetylhydrolase (PAF-AH) activity in vitro similar to that of human serum with respect to its substrate affinity and specificity and thus designated L-PAF-AH. On the other hand, the primary amino acid sequence of L-PAF-AH is homologous to the α1-subunit of the bovine brain PAF-AH isoform I. The L-PAF-AH was proven to be an intracellular protein, which was encoded unanimously and expressed similarly in either pathogenic or saprophytic leptospires. Mongolian gerbil is an appropriate experimental model to study the PAF-AH level in serum with its basal activity level comparable to that of human while elevated directly associated with the course of pulmonary hemorrhage during severe leptospirosis. Mortality occurred around the peak of pulmonary hemorrhage, along with the transition of the PAF-AH activity level in serum, from the increasing phase to the final decreasing phase. Limited clinical data indicated that the serum activity of PAF-AH was likely to be elevated in the patients infected by L. interrogans serogroup Icterohaemorrhagiae, but not in those infected by other less severe serogroups. Although L-PAF-AH might be released into the micro-environment via cell lysis, its PAF-AH activity apparently contributed little to this elevation. Therefore, the change of PAF-AH in serum not only may be influential for pulmonary hemorrhage, but also seems suitable for disease monitoring to ensure prompt clinical treatment, which is critical for reducing the mortality of severe leptospirosis
Malaria and obesity: obese mice are resistant to cerebral malaria
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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