681 research outputs found
The temperature of caffeine administered during pregnancy and foetal morphometric parameters
Background: Caffeine is one of the most frequently ingested (at various temperatures) xenobiotics by people. A number of studies have confirmed the negative effect of high doses of caffeine ingested during pregnancy both for the mother and the developing foetus. The aim of this study was to evaluate the relationship between caffeineâs toxicity on development and the administered solutionâstemperature.Materials and methods: The research was conducted on rats. The fertilised females were randomly divided into two main groups: an experimental (E) and a control group (C). The experimental groups received caffeine (30 mg/day) in10 (E1), 25 (E2) and 45°C (E3). The females in the control group were given water at the same temperature (C1, C2 and C3). On the 21st day of pregnancy, the pregnant females were killed by decapitation using a specially prepared laboratory guillotine and were assessed morphometric parameters of foetuses.Results and Conclusions: Based on this work showed that: the embryotoxic effect of caffeine was only confined to a reduction in the number of offspring; the greatest changes in the morphometric parameters occurred in foetuses whose mothers received caffeine at 10°C; in the control groups, the greatest changes were observed in foetuses whose mothers were given water at 10°C during pregnancy
WTC2005-63951 TURBOJET ENGINE DEMONSTRATION WITH A HIGH TEMPERATURE AIR FOIL BEARING
ABSTRACT Recent tests demonstrated successful operation of a turbojet engine with a compliant foil air bearing using a new high-temperature solid lubricant coating. The hot section rolling element bearing and corresponding lubrication system were replaced with a compliant foil air bearing using a composite solid lubricant coating capable of operating at temperatures well above 650ÂșC (1200ÂșF). Detailed engine integration studies, bearing component rig testing and hot engine simulator tests were completed prior to the successful engine test. The rig and simulator tests verified high temperature capabilities of the bearing and its surface coating, the bearing journal design, bearing dynamic performance, and rotor-bearing system dynamic stability, prior to engine integration and test. Based on these preliminary efforts, the engine and bearing were assembled and tests were conducted that included over 70 start stop cycles (including hot restarts), seven simulated mission cycles and more than 14 hours of run time. The foil bearing and engine operated flawlessly throughout the test. Vibrations were very low and all temperatures and pressures were as expected. The post-test inspection revealed that the bearing, journal and coating were all in excellent condition. Keywords: compliant foil bearing, high temperature coating, solid film lubricant, gas turbine engine, and turbojet engine. INTRODUCTION Gas turbine engines having high specific thrust, high fuel efficiency, and are both durable and maintenance free are needed for a wide range of applications such as aerial targets, drones, Uninhabited Air and Air Combat Vehicles (UAV/UCAV). For example, highly efficient engines can increase UAV range and loiter time for greater data gathering. When used in drones or target systems, the quality of pilo
Integration of genetics into a systems model of electrocardiographic traits using humanCVD BeadChip
<p>BackgroundâElectrocardiographic traits are important, substantially heritable determinants of risk of arrhythmias and sudden cardiac death.</p>
<p>Methods and ResultsâIn this study, 3 population-based cohorts (n=10 526) genotyped with the Illumina HumanCVD Beadchip and 4 quantitative electrocardiographic traits (PR interval, QRS axis, QRS duration, and QTc interval) were evaluated for single-nucleotide polymorphism associations. Six gene regions contained single nucleotide polymorphisms associated with these traits at P<10â6, including SCN5A (PR interval and QRS duration), CAV1-CAV2 locus (PR interval), CDKN1A (QRS duration), NOS1AP, KCNH2, and KCNQ1 (QTc interval). Expression quantitative trait loci analyses of top associated single-nucleotide polymorphisms were undertaken in human heart and aortic tissues. NOS1AP, SCN5A, IGFBP3, CYP2C9, and CAV1 showed evidence of differential allelic expression. We modeled the effects of ion channel activity on electrocardiographic parameters, estimating the change in gene expression that would account for our observed associations, thus relating epidemiological observations and expression quantitative trait loci data to a systems model of the ECG.</p>
<p>ConclusionsâThese association results replicate and refine the mapping of previous genome-wide association study findings for electrocardiographic traits, while the expression analysis and modeling approaches offer supporting evidence for a functional role of some of these loci in cardiac excitation/conduction.</p>
Validation of the Chronic Airways Assessment Test in the NOVELTY Study
Peer reviewedPostprin
Periodontal therapy and treatment of hypertension-alternative to the pharmacological approach. A systematic review and meta-analysis
Aim: Quantitative comparison of the effects of intensive (IPT) or conventional (CPT) periodontal treatment on arterial blood pressure, endothelial function and inflammatory/metabolic biomarkers. / Materials and methods: A systematic search was conducted to identify randomized controlled trials (RCT) of IPT (supra and subgingival instrumentation). Eight RCTs were included in the meta-analysis. Difference in change of systolic blood pressure (SBP) and diastolic blood pressure (DBP) before and after IPT or CPT were the primary outcomes. The secondary outcomes included: endothelial function and selected inflammatory/anti-inflammatory (CRP, IL-6, IL-10, IFN-Îł) and metabolic biomarkers (HDL, LDL, TGs). / Results: The overall effect estimates (pooled Weighted Mean Difference (WMD)) of the primary outcome for SBP and DBP was â4.3 mmHg [95%CI: â9.10â0.48], p = 0.08 and â3.16 mmHg [95%CI: â6.51â0.19], p = 0.06 respectively. These studies were characterized by high heterogeneity. Therefore, random effects model for meta-analysis was performed. Sub-group analyses confirmed statistically significant reduction in SBP [WMD = â11.41 mmHg (95%CI: â13.66, â9.15) P < 0.00001] and DBP [WMD = â8.43 mmHg (95%CI: â10.96,â5.91)P < 0.00001] after IPT vs CPT among prehypertensive/hypertensive patients, while this was not observed in normotensive individuals. The meta-analyses showed significant reductions in CRP and improvement of endothelial function following IPT at all analysed timepoints. / Conclusions: IPT leads to improvement of the cardiovascular health in hypertensive and prehypertensive individuals
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Pharmacological characterization of nanoparticle-induced platelet microaggregation using quartz crystal microbalance with dissipation: comparison with light aggregometry
Background: Engineered nanoparticles (NPs) can induce platelet activation and aggregation, but the mechanisms underlying these interactions are not well understood. This could be due in part to use of devices that study platelet function under quasi-static conditions with low sensitivity to measure platelet microaggregation. Therefore, in this study we investigated the pharmacological pathways and regulators of NP-induced platelet microaggregation under flow conditions at nanoscale using quartz crystal microbalance with dissipation (QCM-D) and compared the data thus obtained with those generated by light aggregometry. Methods: Blood was collected from healthy volunteers, and platelet-rich plasma was obtained. Thrombin receptor-activating peptide, a potent stimulator of platelet function, and pharmacological inhibitors were used to modulate platelet microaggregation in the presence/absence of silica (10 nm and 50 nm) and polystyrene (23 nm) NPs. Light aggregometry was used to study platelet aggregation in macroscale. Optical, immunofluorescence, and scanning electron microscopy were also used to visualize platelet aggregates. Results: Platelet microaggregation was enhanced by thrombin receptor-activating peptide, whereas prostacyclin, nitric oxide donors, acetylsalicylic acid, and phenanthroline, but not adenosine diphosphate (ADP) blockers, were able to inhibit platelet microaggregation. NPs caused platelet microaggregation, an effect not detectable by light aggregometry. NP-induced microaggregation was attenuated by platelet inhibitors. Conclusion: NP-induced platelet microaggregation appears to involve classical proaggregatory pathways (thromboxane A2-mediated and matrix metalloproteinase-2-mediated) and can be regulated by endogenous (prostacyclin) and pharmacological (acetylsalicylic acid, phenanthroline, and nitric oxide donors) inhibitors of platelet function. Quartz crystal microbalance with dissipation, but not light aggregometry, is an appropriate method for studying NP-induced microaggregation
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