Prophylactic warfarin DR of 10-20% is effective in maintaining therapeutic anticoagulation in patients initiating TMP-SMX. An expectant strategy consisting of no change in warfarin dosing with short-term INR follow-up appears reasonable in patients treated with levofloxacin.

We investigated the influence of aging on cardiac baroreflex function during dynamic exercise in seven young (22 Ϯ 1 yr) and eight older middle-aged (59 Ϯ 2 yr) healthy subjects. Carotid-cardiac baroreflex function was assessed at rest and during moderate-intensity steadystate cycling performed at 50% heart rate reserve (HRR). Five-second pulses of neck pressure and neck suction from ϩ40 to Ϫ80 Torr were applied to determine the operating point gain (GOP) and maximal gain (GMAX) of the full carotid-cardiac baroreflex function curve and examine baroreflex resetting during exercise. At rest, mean arterial pressure (MAP) and heart rate were similar between the younger and older subjects. In contrast, the resting GOP and GMAX were significantly lower in the older subjects. The increase in MAP from rest to exercise was greater in the older subjects (⌬ ϩ20 Ϯ 2 older vs. ⌬ ϩ6 Ϯ 3 younger mmHg; P Ͻ 0.001). However, the GOP was similar in both groups during exercise because of a reduction in the younger subjects. In contrast, GMAX was unchanged from rest and therefore remained lower in older subjects (Ϫ0.19 Ϯ 0.05 older vs. Ϫ0.42 Ϯ 0.05 younger beats ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; 50% HRR; P Ͻ 0.001). Furthermore, exercise resulted in an upward and rightward resetting of the cardiac baroreflex function curve in both groups. Collectively, these findings suggest that the cardiac baroreflex function curve appropriately resets during exercise in older subjects but operates at a reduced GMAX primarily because of age-related reductions in carotidcardiac control manifest at rest. arterial baroreceptors; aging; heart rate HEALTHY AGING HAS BEEN associated with impaired arterial baroreflex control of heart rate (HR; see Refs. 10,17,25,33), vasomotor tone (8), and blood pressure (23) under resting conditions. However, little is known about how aging alters baroreflex function during dynamic exercise. Importantly, alterations noted at rest cannot simply be extrapolated to exercise because peripheral feedback from skeletal muscle (i.e., exercise pressor reflex; EPR) and feedforward central neural inputs (i.e., central command) modulate arterial baroreflex control during exercise, influencing reflex sensitivity and also contributing to the resetting of the baroreflex function curve (13,27). Moreover, EPR function may be attenuated in older subjects (24), thereby leading to decreases in input from the EPR to the baroreflex, potentially altering baroreflex sensitivity and resetting characteristics. In addition, it is possible that an agerelated enhancement of central command may also modify the baroreflex during exercise (5). Thus it is important to consider the influence of healthy aging on baroreflex function and resetting during dynamic exercise. This is particularly relevant from a clinical standpoint since older subjects are increasingly being encouraged to exercise and decreases in baroreflex control of HR can increase the occurrence of ventricular arrhythmias during physical activity (1,38).Limited studies have attempted to investigate ag...

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A tunable stochastic geometry based Three-Dimensional (3-D) scattering model for emerging land mobile radio cellular systems is proposed. Uniformly distributed scattering objects are assumed around the Mobile Station (MS) bounded within an ellipsoidal shaped Scattering Region (SR) hollowed with an elliptically-cylindric scattering free region in immediate vicinity of MS. To ensure the degree of expected accuracy, the proposed model is designed to be tunable (as required) with nine degrees of freedom, unlike its counterparts in the existing literature. The outer and inner boundaries of SR are designed as independently scalable along all the axes and rotatable in horizontal plane around their origin centered at MS. The elevated Base Station (BS) is considered outside the SR at a certain adjustable distance and height w.r.t. position of MS. Closed-form analytical expressions for joint and marginal Probability Density Functions (PDFs) of Angle-of-Arrival (AoA) and Time-of-Arrival (ToA) are derived for both up- and down-links. The obtained analytical results for angular and temporal statistics of the channel are presented along with a thorough analysis. The impact of various physical model parameters on angular and temporal characteristics of the channel is presented, which reveals the comprehensive insight on the proposed results. To evaluate the robustness of the proposed analytical model, a comparison with experimental datasets and simulation results is also presented. The obtained analytical results for PDF of AoA observed at BS are seen to fit a vast range of empirical datasets in the literature taken for various outdoor propagation environments. In order to establish the validity of the obtained analytical results for spatial and temporal characteristics of the channel, a comparison of the proposed analytical results with the simulation results is shown, which illustrates a good fit for 107 scattering points. Moreover, the proposed model is shown to degenerate to various notable geometric models in the literature by an appropriate choice of a few parameters.

In recent years, the synthesis of ammonia (NH3) has been developed by electrocatalytic technology that is a potential way to effectively replace the Haber–Bosch process, which is an industrial synthesis of NH3. Industrial ammonia has caused a series of problems for the population and environment. In the face of sustainable green synthesis methods, the advantages of electrocatalytic nitrogen reduction for synthesis of NH3 in aqueous media have attracted a great amount of attention from researchers. This review summarizes the recent progress on the highly efficient electrocatalysts based on 2D non-metallic nanomaterial and provides a brief overview of the synthesis principle of electrocatalysis and the performance measurement indicators of electrocatalysts. Moreover, the current development of N2 reduction reaction (NRR) electrocatalyst is discussed and prospected.

Internet of Things (IoT) is an emerging domain in which different devices communicate with each other through minimum human intervention. IoT devices are usually operated in hostile and unattended environments. Moreover, routing in current IoT architecture becomes inefficient due to malicious and unauthenticated nodes' existence, minimum network lifetime, insecure routing, etc. This paper proposes a lightweight blockchain based authentication mechanism where ordinary sensors' credentials are stored. As IoT nodes have a short lifespan due to energy depletion, few credentials are stored in the blockchain to achieve lightweight authentication. Moreover, the route calculation is performed by a genetic algorithm enabled software defined network controller, which is also used for on-demand routing to optimize the energy consumption of the nodes in the IoT network. Furthermore, a route correctness mechanism is proposed to check the existence of malicious nodes in the calculated route. Moreover, a detection mechanism is proposed to restrict the malicious nodes' activities, while a malicious node's list is maintained in the blockchain, which is used in the route correctness mechanism. The proposed model is evaluated by performing intensive simulations. The effectiveness of the proposed model is depicted in terms of gas consumption, which shows the optimized utilization of resources. The residual energy of the network shows optimized route calculation, while the malicious node detection method shows the number of packets dropped.

A geometry-based three-dimensional (3D) novel stochastic channel model for air-to-ground (A2G) and ground-to-air (G2A) radio propagation environments is proposed. The vicinity of a ground station (GS) is modelled as surrounded by effective scattering points; whereas the elevated air station's (AS) vicinity is modelled as a scattering-free region. Characterization of the Doppler spectrum, dispersion in the angular domain and second order fading statistics of the A2G/G2A radio communication channels is presented. Closed-form analytical expressions for joint and marginal probability density functions (PDFs) of Doppler shift, power and angle of arrival (AoA) are derived. Next, the paper presents a comprehensive analysis on the characteristics of angular spread on the basis of shape factors (SFs) for A2G/G2A radio propagation environments independently in both the azimuth and elevation planes. The analysis is further extended to second order statistics of the fading channel; where the behaviour of the level crossing rate (LCR), average fade duration (AFD), auto-covariance and coherence distance for the A2G/G2A radio propagation environment is studied. Finally, the impact of physical channel parameters, such as the mobility of AS, the height of AS, the height of GS and the delay of the longest propagation path, on the distribution characteristics of Doppler shift, angular spread and second order statistics is thoroughly studied.