1,951 research outputs found

    Efficacy of a certified modular ultrasound curriculum

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    Background In recent years, ultrasound (US) has become more incorporated into anesthesia and intensive care medicine. The German Anesthesia Society established a modular curriculum to teach US skills. Until now, the efficacy of this modular curriculum has not been validated. Objective The main objective of this study was to determine whether there is an increase of knowledge and of psychomotor skills for the trainees in this curriculum. Material and methods After ethical committee approval, 41 anesthesia physicians were enrolled. To determine the increase of knowledge and of practical skills theoretical and practical tests performed were evaluated before and after two different US courses. Results Comparing before and after course tests, the participants showed significant improvement in theoretical multiple choice tests (p = 0.008). Regarding psychomotor skills following course 1, the trainees improved significantly in the time needed to perform the two practical tests (p = 0.03), but not in the performance of the test. Better needle visualization during simulated US-guided vessel puncture (p = 0.52) and better identification of the anatomical structures in the axillary region (p = 0.56) could not be achieved. Conclusion This study shows that although this US course curriculum has positively enhanced the trainees’ theoretical knowledge of US practice, it does not enhance the practical application of that theoretical knowledge. To improve this curriculum, a supervised clinically practical training should follow the course.Hintergrund Ultraschall (US) hat in den letzten Jahren zunehmend Einzug in die Anästhesie und Intensivmedizin erhalten. Die Deutsche Gesellschaft für Anästhesiologie & Intensivmedizin hat ein modulares Kurssystem zur Vermittlung von US-Kompetenzen entwickelt. Die Wirksamkeit dieses modularen Curriculums wurde bisher nicht validiert. Ziel Ziel dieser Studie war zu ermitteln, ob es bei den Teilnehmern durch den Besuch von Modulen dieses Kurssystems zu einer Verbesserung theoretischer Kenntnisse und praktischer Fertigkeiten kommt. Material und Methode Nach Zustimmung durch die Ethikkommission wurden 41 Anästhesisten in die Studie eingeschlossen. Um den Zugewinn an Wissen und praktischen Fertigkeiten zu ermitteln, wurden theoretische und praktische Tests vor und nach zwei verschiedenen US-Kursen ausgewertet. Ergebnisse Nach den Kursen zeigten die Teilnehmer eine signifikante Verbesserung in den Ergebnissen der Multiple-Choice-Tests (p = 0,008). Hinsichtlich der psychomotorischen Fähigkeiten nach Kurs 1 verbesserten sich die Teilnehmer in der zur Durchführung der beiden praktischen Tests benötigten Zeit signifikant (p = 0,03), nicht aber in der Durchführung der Tests. Die praktischen Aufgaben konnten nach dem Kurs 1 zwar signifikant schneller durchgeführt werden (p = 0,03), die Qualität der Nadelführung (p = 0,52) und die korrekte Benennung anatomischer Strukturen in der Achselregion konnten aber nicht verbessert werden. Schlussfolgerung Diese Studie zeigt, dass obwohl dieses Kurssystem die theoretischen Kenntnisse über die US-Praxis verbessert hat, die praktische Anwendung dieses theoretischen Wissens aber nicht verbessert werden konnten. Um dieses Curriculum zu verbessern, sollte es von einem praktischen Training unter Anleitung ergänzt werden

    Investigation into the benefits of reduced oil flows in internal combustion engines

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    The engine lubrication system is a vital element for engine health but causes a parasitic load on the engine which increases the fuel consumption: this load can be reduced by matching the oil flow to lubricating requirements using a variable displacement oil pump. In a first stage, two variable displacement oil pumps were installed on a 2.4-L diesel engine; experiments over the New European Drive cycle showed reductions in fuel consumption of up to 3.4% and up to 5.8% over the urban phase of the cycle. A variable displacement oil pump was subsequently installed on an instrumented engine capturing over 100 metal and fluid temperatures within the engine structure. This showed that reducing oil flows resulted in lower oil temperature by up to 4 °C during cold-start New European Drive cycle but hotter cylinder liner temperatures by up to 6 °C. The higher cylinder wall temperatures caused an increase of 3% in oxides of nitrogen emissions but a reduction of 3%−5% in carbon monoxide and hydrocarbon emissions. Finally, an energy flow analysis showed that the variable displacement oil pump can reduce oil pump energy consumption by 160 kJ (32%) but that this led to a 400-kJ reduction in friction and accessory work. These findings highlight the need for a system-level rather than a component-level approach to engine lubrication design to capture key thermal interactions. </jats:p

    Systems optimisation of an active thermal management system during engine warm-up

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    Active thermal management systems offer a potential for small improvements in fuel consumption that will contribute to upcoming legislation on carbon dioxide emissions. These systems offer new degrees of freedom for engine calibration; however, their full potential will only be exploited if a systems approach to their calibration is adopted, in conjunction with other engine controls. In this work, a design-of-experiments approach is extended to allow its application to transient drive cycles performed on a dynamic test stand. Experimental precision is of crucial importance in this technique since even small errors would obscure the effects of interest. The dynamic behaviour of the engine was represented mathematically in a manner that enabled conventional steady state modelling approaches to be employed in order to predict the thermal state of critical parts of the engine as a function of the actuator settings. A 17-point test matrix was undertaken, and subsequent modelling and optimisation procedures indicated potential 2–3% fuel consumption benefits under iso-nitrogen oxide conditions. Reductions in the thermal inertia appeared to be the most effective approach for reducing the engine warm-up time, which translated approximately to a 1.3% reduction in the fuel consumption per kilogram of coolant. A novel oil-cooled exhaust gas recirculation system showed the significant benefits of cooling the exhaust gases, thereby reducing the inlet gas temperature by 5 °C and subsequently the nitrogen oxide emissions by 6%, in addition to increasing the warm-up rate of the oil. This suggested that optimising the thermal management system for cooling the gases in the exhaust gas recirculation system can offer significant improvements. For the first time this paper presents a technique that allows simple predictive models of the thermal state of the engine to be integrated into the calibration process in order to deliver the optimum benefit. In particular, it is shown how the effect of the thermal management system on the nitrogen oxides can be traded off, by advancing the injection timing, to give significant improvements in the fuel consumption. </jats:p

    Estimated Ultraviolet Radiation Doses in Wetlands in Six National Parks

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    Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia (Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/ Kings Canyon (Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools, field characterization of vegetative features, and quantification of DOC concentration and spectral absorbance. UV-B dose estimates were made for the summer solstice, at a depth of 1 cm in each wetland. The mean dose across all wetlands and parks was 19.3 W-h m-2 (range of 3.4–32.1 W-h m-2). The mean dose was lowest in Acadia (13.7 W-h m-2) and highest in Rocky (24.4 W-h m-2). Doses were significantly different among all parks. These wetland doses correspond to UV-B flux of 125.0 µW cm-2 (range 21.4–194.7 µW cm)2) based on a day length, averaged among all parks, of 15.5 h. Dissolved organic carbon (DOC), a key determinant of water-column UV-B flux, ranged from 0.6 (analytical detection limit) to 36.7 mg C L-1 over all wetlands and parks, and reduced potential maximal UV-B doses at 1-cm depth by 1%–87 %. DOC concentration, as well as its effect on dose, was lowest in Sequoia and highest in Acadia (DOC was equivalent in Acadia, Glacier, and Rocky). Landscape reduction of potential maximal UV-B doses ranged from zero to 77% and was lowest in Sequoia. These regional differences in UV-B wetland dose illustrate the importance of considering all aspects of exposure in evaluating the potential impact of UV-B on aquatic organisms

    Histamine receptors in GtoPdb v.2021.3

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    Histamine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Histamine Receptors [80, 173]) are activated by the endogenous ligand histamine. Marked species differences exist between histamine receptor orthologues [80]. The human and rat H3 receptor genes are subject to significant splice variance [12]. The potency order of histamine at histamine receptor subtypes is H3 = H4 &gt; H2 &gt; H1 [173]. Some agonists at the human H3 receptor display significant ligand bias [182]. Antagonists of all 4 histamine receptors have clinical uses: H1 antagonists for allergies (e.g. cetirizine), H2 antagonists for acid-reflux diseases (e.g. ranitidine), H3 antagonists for narcolepsy (e.g. pitolisant/WAKIX; Registered) and H4 antagonists for atopic dermatitis (e.g. adriforant; Phase IIa) [173] and vestibular neuritis (AUV) (SENS-111 (Seliforant, previously UR-63325), entered and completed vestibular neuritis (AUV) Phase IIa efficacy and safety trials, respectively) [216, 8]

    Histamine receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

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    Histamine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Histamine Receptors [75, 163]) are activated by the endogenous ligand histamine. Marked species differences exist between histamine receptor orthologues [75]. The human and rat H3 receptor genes are subject to significant splice variance [12]. The potency order of histamine at histamine receptor subtypes is H3 = H4 > H2 > H1 [163]. Some agonists at the human H3 receptor display significant ligand bias [171]. Antagonists of all 4 histamine receptors have clinical uses: H1 antagonists for allergies (e.g. cetirizine), H2 antagonists for acid-reflux diseases (e.g. ranitidine), H3 antagonists for narcolepsy (e.g. pitolisant/WAKIX; Registered) and H4 antagonists for atopic dermatitis (e.g. ZPL-3893787; Phase IIa) [163] and vestibular neuritis (AUV) (SENS-111 (Seliforant, previously UR-63325), entered and completed vestibular neuritis (AUV) Phase IIa efficacy and safety trials, respectively) [205, 8]

    Histamine receptors in GtoPdb v.2023.1

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    Histamine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Histamine Receptors [80, 174]) are activated by the endogenous ligand histamine. Marked species differences exist between histamine receptor orthologues [80]. The human and rat H3 receptor genes are subject to significant splice variance [12]. The potency order of histamine at histamine receptor subtypes is H3 = H4 > H2 > H1 [174]. Some agonists at the human H3 receptor display significant ligand bias [183]. Antagonists of all 4 histamine receptors have clinical uses: H1 antagonists for allergies (e.g. cetirizine), H2 antagonists for acid-reflux diseases (e.g. ranitidine), H3 antagonists for narcolepsy (e.g. pitolisant/WAKIX; Registered) and H4 antagonists for atopic dermatitis (e.g. adriforant; Phase IIa) [174] and vestibular neuritis (AUV) (SENS-111 (Seliforant, previously UR-63325), entered and completed vestibular neuritis (AUV) Phase IIa efficacy and safety trials, respectively) [217, 8]
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