13,973 research outputs found
Metabolism of ticagrelor in patients with acute coronary syndromes.
© The Author(s) 2018Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (nâ=â117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180âmg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.Peer reviewedFinal Published versio
Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles
As the integration of wind generation displaces conventional plants, system inertia provided by rotating mass declines, causing concerns over system frequency stability. This paper implements an advanced stochastic scheduling model with inertia-dependent fast frequency response requirements to investigate the challenges on the primary frequency control in the future Great Britain electricity system. The results suggest that the required volume and the associated cost of primary frequency response increase significantly along with the increased capacity of wind plants. Alternative measures (e.g. electric vehicles) have been proposed to alleviate these concerns. Therefore, this paper also analyses the benefits of primary frequency response support from electric vehicles in reducing system operation cost, wind curtailment and carbon emissions
Six Top Messages of New Physics at the LHC
Six top signatures provide a novel probe of new physics. We discuss
production of six top quarks as the decay products of a pair of top partners in
the setting of a composite Higgs model, and argue that the six top signal may
generically provide one of the first final states to show a discrepancy. We
construct an analysis based on quantities such as and the numbers of jets
which are tagged as boosted tops, s, or containing -tags, and show that
the LHC with 3~ab can discover top partners with masses up to around 2.5
TeV in the six top signature.Comment: 15 pages, 6 figures, and 2 table
Exploring Oxidation in the Remote Free Troposphere: Insights from Atmospheric Tomography (ATom)
Earth's atmosphere oxidizes the greenhouse gas methane and other gases, thus determining their lifetimes and oxidation products. Much of this oxidation occurs in the remote, relatively clean free troposphere above the planetary boundary layer, where the oxidation chemistry is thought to be much simpler and better understood than it is in urban regions or forests. The NASA airborne Atmospheric Tomography study (ATom) was designed to produce cross sections of the detailed atmospheric composition in the remote atmosphere over the Pacific and Atlantic Oceans during four seasons. As part of the extensive ATom data set, measurements of the atmosphere's primary oxidant, hydroxyl (OH), and hydroperoxyl (HOâ) are compared to a photochemical box model to test the oxidation chemistry. Generally, observed and modeled median OH and HOâ agree to with combined uncertainties at the 2Ï confidence level, which is ~±40%. For some seasons, this agreement is within ~±20% below 6 km altitude. While this test finds no significant differences, OH observations increasingly exceeded modeled values at altitudes above 8 km, becoming ~35% greater, which is near the combined uncertainties. Measurement uncertainty and possible unknown measurement errors complicate tests for unknown chemistry or incorrect reaction rate coefficients that would substantially affect the OH and HOâ abundances. Future analysis of detailed comparisons may yield additional discrepancies that are masked in the median values
Grown-in defects and defects produced by 1-Me electron irradiated in Al0.3Ga0.7As P-N junction solar cells
Studies of grown-in defects and defects produced by the one-MeV electron irradiation in Al sub 0.3 Ga sub 0.7As p-n junction solar cells fabricated by liquid phase epitaxial (LPE) technique were made for the unirradiated and one-MeV electron irradiated samples, using DLTS and C-V methods. Defect and recombination parameters such as energy level, defect density, carrier capture cross sections and lifetimes were determined for various growth, annealing, and irradiation conditions
Analytical modeling of water wave interaction with a bottom-mounted surface-piercing porous cylinder in front of a vertical wall
The interaction of water wave with a bottom-mounted surface-piercing porous cylinder near a rigid vertical wall is investigated by an analytical model newly developed in the present work within the context of linear potential flow theory. The image principle is used to transfer the original problem in bounded water into the equivalent problem of wave interaction with two symmetrical porous cylinders in open seas in the presence of bi-directional incident waves. The velocity potential is analytically derived by means of the eigen function expansion along with the matching technique. Furthermore, a new alternative method for the evaluation of wave force is developed via the application of the HaskindâHanaoka relation to a porous structure. In this method, an auxiliary radiation potential is introduced to replace the diffraction potential for the calculation of wave force. The auxiliary radiation potential used here is due to the oscillation of a porous cylinder in front of a wall. The image principle is used again to search the solution of the wave radiation problem in bounded water and the original radiation problem is then transferred to that due to two porous cylinders undergoing in-phase orout-of-phase motions in open seas. After the validation of the developed model, detailed parametric study is carried out. The porosity of the cylinder, incident wave heading and spacing between the cylinder and the wall are systematically adjusted to investigate their effects on the wave force as well as the wave elevation. The extension of our model to the case of a cylinder array in front of a wall has also been performed, and the associated phenomenon has been explored
Event-triggered distributed model predictive control for resilient voltage control of an islanded microgrid
This article addresses the problem of distributed secondary voltage control of an islanded microgrid (MG) from a cyberâphysical perspective. An eventâtriggered distributed model predictive control (DMPC) scheme is designed to regulate the voltage magnitude of each distributed generators (DGs) in order to achieve a better tradeâoff between the control performance and communication and computation burdens. By using two novel event triggering conditions that can be easily embedded into the DMPC for the application of MG control, the computation and communication burdens are significantly reduced with negligible compromise of control performance. In addition, to reduce the sensor cost and to eliminate the negative effects of nonlinearity, an adaptive nonasymptotic observer is utilized to estimate the internal and output signals of each DG. Thanks to the deadbeat observation property, the observer can be applied periodically to cooperate with the DMPCâbased voltage regulator. Finally, the effectiveness of the proposed control method has been tested on a simple configuration with four DGs and the modified IEEEâ13 test system through several representative scenarios
Pengaruh Pengurangan Diameter Valvestem Dan Penambahan Radius Valveneck Terhadap Performa Motor Bakar Honda Supra Fit 100 CC
Salah satu untuk meningkatkan performa dari sepeda motor adalah dengan melakukan penggantian katup standard ke katup racing. Katup racing ini bertujuan untuk memperlancar aliran udara yang masuk ke ruang bakar. Katup racing, biasanya, cara memodifikasinya adalah dengan melakukan pengurangan diameter pada batang katup. Pemilihan diameter katup pada penelitian ini adalah pengurangan sebesar 0,7 mm, 0,9 mm, dan 1,1 mm, dan membandingkan ketiga diameter dengan katup ukuran standard. Metode pengujian yang dilakukan pada penelitian ini adalah dengan melakukan simulasi aliran dengan menggunakan program komputer ANSYS. Serta dengan melakukan uji dynotest untuk mengetahui peningkatan daya dan torsi, sebelum dan sesudah dilakukan penggantian pada masing-masing variasi pada katup. Hasil yang didapatkan setelah melakukan simulasi adalah katup dengan diameter batang yang diperkecil menghasilkan pressure drop yang lebih kecil dan velocity yang besar. Hasil tersebut dicapai oleh katup dengan pengurangan sebesar 0,9 mm. Untuk hasil dynotest, daya tertinggi dicapai oleh katup dengan pengurangan sebesar 1,1 mm. yaitu 6,8 HP, mengalami pengingkatan sebesar 17,24%. Sedangkan torsi maksimum dicapai oleh katup dengan pengurangan 0,9 mm, yaitu 7,39 N.m, meningkat sebesar 14,75% dari katup standard
Shape Synthesis in Mechanical Design
The shaping of structural elements in the area of mechanical design is a recurrent problem. The mechanical designer, as a rule, chooses what is believed to be the âsimplestâ shapes, such as the geometric primitives: lines, circles and, occasionally, conics. The use of higher-order curves is usually not even considered, not to speak of other curves than polynomials. However, the simplest geometric shapes are not necessarily the most suitable when the designed element must withstand loads that can lead to failure-prone stress concentrations. Indeed, as mechanical designers have known for a while, stress concentrations occur, first and foremost, by virtue of either dramatic changes in curvature or extremely high values thereof. As an alternative, we propose here the use of smooth curves that can be simply generated using standard concepts such as non-parametric cubic splines. These curves can be readily used to produce either extruded surfaces or surfaces of revolution.
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