3,301 research outputs found
Rate Regions for the Partially-Cooperative Relay Broadcast Channel with Non-causal Side Information
In this work, we consider a partially cooperative relay broadcast channel
(PC-RBC) controlled by random parameters. We provide rate regions for two
different situations: 1) when side information (SI) S^n on the random
parameters is non-causally known at both the source and the relay and, 2) when
side information S^n is non-causally known at the source only. These achievable
regions are derived for the general discrete memoryless case first and then
extended to the case when the channel is degraded Gaussian and the SI is
additive i.i.d. Gaussian. In this case, the source uses generalized dirty paper
coding (GDPC), i.e., DPC combined with partial state cancellation, when only
the source is informed, and DPC alone when both the source and the relay are
informed. It appears that, even though it can not completely eliminate the
effect of the SI (in contrast to the case of source and relay being informed),
GDPC is particularly useful when only the source is informed.Comment: 7 pages, Proc. of IEEE International Symposium on Information theory,
ISIT 2007, Nice, Franc
Physiology of haemostasis
© 2019 Elsevier Ltd Haemostasis is a complex process that ensures the maintenance of blood flow under normal physiological conditions and prevents major blood loss following vascular injury. The process is tightly regulated to prevent pathological thrombosis. Normal haemostasis relies on the delicate balance of prothrombotic and anticoagulant processes, where five components play a significant role in maintaining the haemostasis, these include: (1) endothelial cells; (2) platelets which are key to platelet plug formation; (3) coagulation factors that are essential to formation of insoluble fibrin clot; (4) coagulation inhibitors; and (5) fibrinolysis. This article will provide an overview of the current concepts of haemostasis, and through this we will explain how antiplatelets and antithrombotic drugs work, as well as provide a basic understanding of how to interpret clotting tests used to measure coagulation disorders
Sensitivity of the synaptic membrane Na+/Ca2+ exchanger and the expressed NCX1 isoform to reactive oxygen species
AbstractTwo plasma membrane proteins, the Na+/Ca2+ exchanger (NCX) and the Ca2+-ATPase, are major regulators of free intraneuronal Ca2+ levels as they are responsible for extrusion of Ca2+ from the intracellular to the extracellular medium. Because disruption of cellular Ca2+ regulation plays a role in damage occurring under conditions of oxidative stress, studies were conducted to assess the sensitivity of the NCX to reactive oxygen species (ROS). Exchanger activity in brain synaptic plasma membranes and in transfected CHO-K1 cells was inhibited following brief exposure to the peroxyl radical generating azo initiator 2,2′-azobis(2-amidinopropane)dihydrochloride (AAPH) and to peroxynitrite. Incubation with hydrogen peroxide did not alter NCX activity, even at 800 μM concentration. In CHO-K1 cells transiently transfected with the NCX1 isoform of the exchanger, AAPH treatment decreased the maximal transport capacity (Vmax), whereas the Kact remained unchanged. Peroxynitrite led to an increase in Kact with no change in Vmax. Loss of activity following exposure to either AAPH or peroxynitrite was associated with the formation of high molecular weight aggregates of NCX, and AAPH also caused fragmentation of the exchanger protein. These findings suggest that the NCX is sensitive to biologically relevant ROS and could be involved in the loss of Ca2+ homeostasis observed under oxidative stress
Statistical Analysis of a Linear Multi-Step Numerical Treatment
The aim of this paper is to compare the relative accuracies between predictor-corrector methods, Adams-Bashforth method and Adams-Moulton method for solving initial value Differential Equations numerically to observe which methods tend to function well in which step-size brackets as well as which ones provide the minimum amount of error when compared to the true value. The statistical analysis shows that there is always a small amount of error present using Heun’s method; however, the error is rarely large enough unless the function is rapidly rising
Non supersymmetric strong coupling background from the large N quantum mechanics of two matrices coupled via a Yang-Mills interaction
We derive the planar large N non-supersymmetric background of the quantum
mechanical hamiltonian of two hermitean matrices coupled via a Yang-Mills
interaction, in terms of the density of eigenvalues of one of the matrices.
This background satisfies an implicit non linear integral equation, with a
perturbative small coupling expansion and a solvable large coupling solution,
which is obtained. The energy of system and the expectation value of several
correlators are obtained in this strong coupling limit. They are free of
infrared divergences.Comment: Latex, 13 page
COMPARISON OF XANTHINE OXIDASE INHIBITORS IN GOUTY PATIENTS WITH HYPERURICEMIA
Objective: Febuxostat is more effective/superior to Allopurinol in reducing the serum uric acid (SUA) level in the treatment of hyperuricemic withgout.Methods: This randomized control study included 200 hyperuricemic patients with gout, at Multi-center study including Outdoor Departments ofMedicine from four different hospitals of Lahore, Pakistan. Patients age range 18-50 years diagnosis with hyperuricemia and gout, SUA >8 mg/dlwere included while severe renal impairment and alanine aminotransferase and aspartate aminotransferase patients were excluded from the study.Results: About 200 patients treated with hyperuricemic with gout were randomly divided into four groups (50%) patients were in each groupreceived different treatment. Out of 200 patients, 118 (59%) were male and 82 (41%) were female with mean age 42.37±9.47 years. Among theFebuxostat group, patients' success rate of lowering SUA level was found to be 32 (64%) as compared to Allopurinol 16 (32%). Drug compliance wassimilar among treatment groups, i.e. Allopurinol and Febuxostat while the trend toward drug compliance in Allopurinol + Vitamin C and Febuxostat +Vitamin C groups showed similar in number.Conclusion: Febuxostat is safe and effective to Allopurinol for the treatment of hyperuricemia with gout as the Febuxostat has a significant associationwith lowering SUA concentration <6 mg/dl. It is concluded that although Febuxostat is safe and effect alone in gouty patients, but it has somehow alittle effect with Vitamin C especially in patients who are feeble.Keywords: Febuxostat, Allopurinol, Serum uric acid.Â
Guided Waves for the Inspection of Titanium Diffusion Bonds
The aggressive environment encountered by the high speed civil transport (supersonic) aircraft (HSCT) places severe requirements on the types of materials used in its construction. The state-of- the-art materials available to the commercial aerospace industry will not meet these severe environmental requirements. New materials have been evaluated that will meet these severe environmental requirements. One such material is the super plastic formed/diffusion bonded (SPF/DB) titanium. Structures with this material have been fabricated to be used on the HSCT aircraft. Because the HSCT is a commercial program, the FAA requires that nondestructive evaluation techniques must be developed for the inspection of these structures
Retrospective Study of Midazolam Protocol for Prehospital Behavioral Emergencies
Introduction: Agitated patients in the prehospital setting pose challenges for both patient care and emergency medical services (EMS) provider safety. Midazolam is frequently used to control agitation in the emergency department setting; however, limited data exist in the prehospital setting. We describe our experience treating patients with midazolam for behavioral emergencies in a large urban EMS system. We hypothesized that using midazolam for acute agitation leads to improved clinical conditions without causing significant clinical deterioration.Methods: We performed a retrospective review of EMS patient care reports following implementation of a behavioral emergencies protocol in a large urban EMS system from February 2014–June 2016. For acute agitation, paramedics administered midazolam 1 milligram (mg) intravenous (IV), 5 mg intramuscular (IM), or 5 mg intranasal (IN). Results were analyzed using descriptive statistics, Levene’s test for assessing variance among study groups, and t-test to evaluate effectiveness based on route.Results: In total, midazolam was administered 294 times to 257 patients. Median age was 30 (interquartile range 24–42) years, and 66.5% were male. Doses administered were 1 mg (7.1%) and 5 mg (92.9%). Routes were IM (52.0%), IN (40.8%), and IV (7.1%). A second dose was administered to 37 patients. In the majority of administrations, midazolam improved the patient’s condition (73.5%) with infrequent adverse events (3.4%). There was no significant difference between the effectiveness of IM and IN midazolam (71.0% vs 75.4%; p = 0.24).Conclusion: A midazolam protocol for prehospital agitation was associated with reduced agitation and a low rate of adverse events
Secure D2D Communication in Large-Scale Cognitive Cellular Networks with Wireless Power Transfer
In this paper, we investigate secure device-to-device (D2D) communication in energy harvesting large-scale cognitive cellular networks. The energy constrained D2D transmitter harvests energy from multi-antenna equipped power beacons (PBs), and communicates with the corresponding receiver using the spectrum of the cellular base stations (BSs). We introduce a power transfer model and an information signal model to enable wireless energy harvesting and secure information transmission. In the power transfer model, we propose a new power transfer policy, namely, best power beacon (BPB) power transfer. To characterize the power transfer reliability of the proposed policy, we derive new closed-form expressions for the exact power outage probability and the asymptotic power outage probability with large antenna arrays at PBs. In the information signal model, we present a new comparative framework with two receiver selection schemes: 1) best receiver selection (BRS), and 2) nearest receiver selection (NRS). To assess the secrecy performance, we derive new expressions for the secrecy throughput considering the two receiver selection schemes using the BPB power transfer policies. We show that secrecy performance improves with increasing densities of PBs and D2D receivers because of a larger multiuser diversity gain. A pivotal conclusion is reached that BRS achieves better secrecy performance than NRS but demands more instantaneous feedback and overhead
Secure D2D Communication in Large-Scale Cognitive Cellular Networks: A Wireless Power Transfer Model
In this paper, we investigate secure device-to-device (D2D) communication in energy harvesting large-scale cognitive cellular networks. The energy constrained D2D transmitter harvests energy from multi-antenna equipped power beacons (PBs), and communicates with the corresponding receiver using the spectrum of the primary base stations (BSs). We introduce a power transfer model and an information signal model to enable wireless energy harvesting and secure information transmission. In the power transfer model, three wireless power transfer (WPT) policies are proposed: 1) cooperative power beacons (CPB) power transfer, 2) best power beacon (BPB) power transfer, and 3) nearest power beacon (NPB) power transfer. To characterize the power transfer reliability of the proposed three policies, we derive new expressions for the exact power outage probability. Moreover, the analysis of the power outage probability is extended to the case when PBs are equipped with large antenna arrays. In the information signal model, we present a new comparative framework with two receiver selection schemes: 1) best receiver selection (BRS), where the receiver with the strongest channel is selected, and 2) nearest receiver selection (NRS), where the nearest receiver is selected. To assess the secrecy performance, we derive new analytical expressions for the secrecy outage probability and the secrecy throughput considering the two receiver selection schemes using the proposed WPT policies. We presented Monte-carlo simulation results to corroborate our analysis and show: 1) secrecy performance improves with increasing densities of PBs and D2D receivers due to larger multiuser diversity gain, 2) CPB achieves better secrecy performance than BPB and NPB but consumes more power, and 3) BRS achieves better secrecy performance than NRS but demands more instantaneous feedback and overhead. A pivotal conclusion is reached that with increasing number of antennas at PBs, NPB offers a comparable secrecy- performance to that of BPB but with a lower complexity
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