Total Power Level Research Articles

2302 A ROLE FOR HEDGEHOG SIGNALLING IN URETERAL STENT INDUCED MORBIDITY

INTRODUCTION AND OBJECTIVES: To assess the fragmentation efficiency of laser lithotripsy along a wide range of pulse energies, frequencies, power settings and different laser fibers, paying special attention to compare high frequency to low frequency lithotripsy using a dynamic and innovative testing procedure free from any human interaction bias. METHODS: An automated, in saline submerged laser fragmentation testing system was developed, where laser emission took place during a pre-determined period of time (30s) with laser fibers moving at constant velocity over the surface of artificial stones (plaster of Paris) and creating a fissure, whose wide, depth and volume were analyzed. Lithotripter settings included different pulse energies (0.2-1.2J), frequencies (5-40Hz), power levels (4-20W) and laser fiber diameters (200 and 550 m), including high frequency vs. low frequency experiments maintaining the same total power, totaling 34 different experimental conditions. RESULTS: Low frequency with high pulse energy settings showed to be several times (2.1-6.2x) more efficient than high frequency with low pulse energy at the same power level for all levels tested (p 0.00001) and was also associated with deeper (p 0.01) and wider (p 0.00001) fissures. A linear correlation was found between pulse energy and fragmentation volume (p 0.00001), fissure wide (p 0.00001) and fissure depth (p 0.00001). No correlation was found between power (W) used and fragmentation volume (p 0.29), fissure depth (p 0.06) or fissure wide (p 0.7). Large fibers are associated with wider fissures (p 0.00001), small fibers with deeper fissures (p 0.00001), whatever the frequency, pulse energy or total power used. No differences were detected concerning laser fiber diameter and fragmentation volume (p 0.81) except at very low pulse energies (0.2J) were the large fiber was less efficient (p 0.015). CONCLUSIONS: At the same total power level, low frequency laser lithotripsy is the most efficient laser lithotripter setting. Elevated power settings using high frequency do not warrant higher fragmentation rates when compared to low frequency high pulse energy settings, even those of several orders of magnitude below. These results emphasize that pulse energy seems to be the key feature in fragmentation efficacy, downplaying both the role of high-frequency and total power setting. Source of Funding: None

2301 IN-VITRO COMPARISON OF HIGH FREQUENCY VS. LOW FREQUENCY LASER LITHOTRIPSY

You have accessJournal of UrologyStone Disease: Basic Research (II)1 Apr 20132301 IN-VITRO COMPARISON OF HIGH FREQUENCY VS. LOW FREQUENCY LASER LITHOTRIPSY Peter Kronenberg and Olivier Traxer Peter KronenbergPeter Kronenberg Amadora, Portugal More articles by this author and Olivier TraxerOlivier Traxer Paris, France More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2242AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES To assess the fragmentation efficiency of laser lithotripsy along a wide range of pulse energies, frequencies, power settings and different laser fibers, paying special attention to compare high frequency to low frequency lithotripsy using a dynamic and innovative testing procedure free from any human interaction bias. METHODS An automated, in saline submerged laser fragmentation testing system was developed, where laser emission took place during a pre-determined period of time (30s) with laser fibers moving at constant velocity over the surface of artificial stones (plaster of Paris) and creating a fissure, whose wide, depth and volume were analyzed. Lithotripter settings included different pulse energies (0.2-1.2J), frequencies (5-40Hz), power levels (4-20W) and laser fiber diameters (200 and 550 μm), including high frequency vs. low frequency experiments maintaining the same total power, totaling 34 different experimental conditions. RESULTS Low frequency with high pulse energy settings showed to be several times (2.1-6.2x) more efficient than high frequency with low pulse energy at the same power level for all levels tested (p<0.00001) and was also associated with deeper (p<0.01) and wider (p<0.00001) fissures. A linear correlation was found between pulse energy and fragmentation volume (p<0.00001), fissure wide (p<0.00001) and fissure depth (p<0.00001). No correlation was found between power (W) used and fragmentation volume (p=0.29), fissure depth (p=0.06) or fissure wide (p=0.7). Large fibers are associated with wider fissures (p<0.00001), small fibers with deeper fissures (p<0.00001), whatever the frequency, pulse energy or total power used. No differences were detected concerning laser fiber diameter and fragmentation volume (p=0.81) except at very low pulse energies (0.2J) were the large fiber was less efficient (p<0.015). CONCLUSIONS At the same total power level, low frequency laser lithotripsy is the most efficient laser lithotripter setting. Elevated power settings using high frequency do not warrant higher fragmentation rates when compared to low frequency high pulse energy settings, even those of several orders of magnitude below. These results emphasize that pulse energy seems to be the key feature in fragmentation efficacy, downplaying both the role of high-frequency and total power setting. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e943 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Peter Kronenberg Amadora, Portugal More articles by this author Olivier Traxer Paris, France More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Dyadic Power Profiles: Power-Contingent Strategies for Value Creation in Negotiation

Using a simulated employment negotiation, we tested the conditional relationships among dyadic power profiles (symmetric high, symmetric low, and asymmetric), the choice and sequencing of strategies, and value creation. We showed that negotiators in symmetric high, symmetric low, and asymmetric power dyads took distinctly different paths to value creation. Value creation was associated with increased mutual accommodation in high-power dyads but with increased contentiousness in low-power dyads. Asymmetric power dyads maximized value creation when they adopted a neutral stance, neither overusing nor underusing any one strategy. Although strategy use was a better predictor of value creation than strategy sequencing, sequences played an increasingly important role in value creation as the level of total power within the negotiation increased.

Effect Factors Analysis of Flow Generation Noise from Muffler Element with Inserted Tube

Using orthogonal experimental design method structure parameters of work piece for muffler element with inserted tube are determined. Flow noise regeneration of them is measured on the self development test bench. Relationship model on total sound power of flow regeneration noise and structure parameter and flow velocity is established utilizing Multiple linear regression method, model parameters are solved making use of hyper static least square method. Significance test of the model is performed, the law of total sound power level for muffler element flow regeneration noise changing with the parameters is discussed. Result shows that the established models is all highly significant under 0.01 levels, and inserted length of outlet tube and inn-diameter of inlet tube have higher effect on the flow generation noise, and decreasing the inserted length and the inn-diameter are in favor of reducing flow generation noise. But inserted length of inlet tube and expansion ratio have little effect on the flow generation noise.

The efficacy of magnesium sulfate loading on microalbuminuria following SIRS: One step forward in dosing

BackgroundsMagnesium has been known for its antioxidative and antiinflammatory properties in many studies. In this study two dosing regimens of magnesium were compared with a placebo control group in order to investigate safety and efficacy of high doses of intravenous magnesium sulfate infusion on critically ill trauma patients. Inflammatory and oxidative factors were measured in this trial.Methods45 trauma patients with systemic inflammatory response syndromes (SIRS) were randomly assigned into 2 treatment and one placebo groups. The high dose group received 15 g MgSO4, low dose group received 7.5 g of MgSO4 over 4 hour infusion, and placebo group received saline alone. The initial and post magnesium sulfate injections levels of tumor necrosis factor alpha (TNF-α), total antioxidant power and lipid peroxidation were measured after 6, 18 and 36 hours. The pre-infusion along with 6 and 36 hour level of microalbuminuria were also determined.ResultsRepeated measurements illustrated that there was no significant difference in TNF-α, total antioxidant power and lipid peroxidation levels among groups during the period of analysis. The microalbuminuria at 36 hour post infusion of high dose group was lower than that of control group (p = 0.024). Patient’s mortality (28 day) was similar among all treatment groups. Both magnesium infusion groups tolerated the drug without experiencing any complications.ConclusionNo evidence for antioxidative and antiinflammatory effects of magnesium in traumatic SIRS positive patients was found. Magnesium in high doses may be recommended for traumatic patients with SIRS status to prevent microalbuminuria.

Two new power allocation schemes for an OFDM cognitive radio with no knowledge on primary users’ interference

SUMMARYIn this paper, we propose two new power loading schemes for an OFDM cognitive radio (CR). The novelty of this paper is that the CR has no knowledge about the interference power introduced by primary users (PUs). In the first scheme, we maximize the total received signal power on all CR subcarriers as the objective function with the two constraints: (i) keeping the interference to the PUs below a given threshold, and (ii) allocating less than peak transmit power as the total power levels on all CR subcarriers. The second proposed scheme is similar to the first one with one more constraint, which is more power loading to the CR subcarriers experiencing higher ratio of channel power gain to the noise power. This third constraint results in increasing CR throughput (similar to the water‐filling scheme). Performances of these schemes are analyzed by numerical and simulation results, which illustrate that the two proposed schemes achieve relatively close to the optimal scheme (in which the secondary transmitter has full knowledge about PUs’ interference power) and outperform the scheme based on estimation of this interference power with an estimation error higher than a given threshold. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Association of Inflammatory Biomarker C-Reactive Protein, Lipid Peroxidation and Antioxidant Capacity Marker with HbF Level in Sickle Cell Disease Patients from Chattisgarh.

This study was undertaken to determine the association of inflammatory biomarker, oxidative stress and antioxidant capacity marker with fetal haemoglobin (HbF) level among sickle cell trait and sickle cell disease (SCD) patients in Chattisgarh. The study group consisted of 51 SCD (SS) patients with painful episode, 49 SCD (SS) patients with steady state, 50 sickle cell trait (AS) and 50 controls. Malondialdehyde (MDA), CRP, total antioxidant power (FARP), total thiol and HbF levels were quantified. We found a significant positive (p<0.0001) association between CRP and MDA levels and its inverse association with HbF level in SS patients. We also observed that antioxidant capacity had significantly positively (p<0.0001) associated with HbF level. The protective effect of HbF was found, because the increase in HbF levels resulted in decrease in lipid peroxidation and inflammation in SCD patients. A decrease in the HbF level and its antioxidant capacity has been associated with the pathogenesis of SCD. These finding may explain the high level of HbF is ameliorating oxidative stress and inflammation in SCD patients.

Optimal Broadcast Scheduling for an Energy Harvesting Rechargeable Transmitter with a Finite Capacity Battery

We consider the minimization of the transmission completion time with a battery limited energy harvesting transmitter in an M-user AWGN broadcast channel where the transmitter is able to harvest energy from the nature, using a finite storage capacity rechargeable battery. The harvested energy is modeled to arrive (be harvested) at the transmitter during the course of transmissions at arbitrary time instants. The transmitter has fixed number of packets for each receiver. Due to the finite battery capacity, energy may overflow without being utilized for data transmission. We derive the optimal offline transmission policy that minimizes the time by which all of the data packets are delivered to their respective destinations. We analyze the structural properties of the optimal transmission policy using a dual problem. We find the optimal total transmit power sequence by a directional water-filling algorithm. We prove that there exist M-1 cut-off power levels such that user i is allocated the power between the i-1st and the ith cut-off power levels subject to the availability of the allocated total power level. Based on these properties, we propose an algorithm that gives the globally optimal offline policy. The proposed algorithm uses directional water-filling repetitively. Finally, we illustrate the optimal policy and compare its performance with several suboptimal policies under different settings.

The performance of a centrifugal fan with enlarged impeller

The influence of enlarged impeller in unchanged volute on G4-73 type centrifugal fan performance is investigated in this paper. Comparisons are conducted between the fan with original impeller and two larger impellers with the increments in impeller outlet diameter of 5% and 10% respectively in the numerical and experimental investigations. The internal characteristics are obtained by the numerical simulation, which indicate there is more volute loss in the fan with larger impeller. Experiment results show that the flow rate, total pressure rise, shaft power and sound pressure level have increased, while the efficiency have decreased when the fan operates with larger impeller. Variation equations on the performance of the operation points for the fan with enlarged impellers are suggested. Comparisons between experiment results and the trimming laws show that the trimming laws for usual situation can predict the performance of the enlarged fan impeller with less error for higher flow rate, although the situation of application is not in agreement. The noise frequency analysis shows that higher noise level with the larger impeller fan is caused by the reduced impeller–volute gap.

Association between Frequency Domain Heart Rate Variability and Unplanned Readmission to Hospital in Geriatric Patients

BackgroundAn accurate prediction of unplanned readmission (UR) after discharge from hospital can facilitate physician's decision making processes for providing better quality of care in geriatric patients. The objective of this study was to explore the association of cardiac autonomic functions as measured by frequency domain heart rate variability (HRV) and 14-day UR in geriatric patients.MethodsPatients admitted to the geriatric ward of a regional hospital in Chiayi county in Taiwan were followed prospectively from July 2006 to June 2007. Those with invasive tubes and those who were heavy smokers, heavy alcohol drinkers, on medications that might influence HRV, or previously admitted to the hospital within 30 days were excluded. Cardiac autonomic functions were evaluated by frequency domain indices of HRV. Multiple logistic regression was used to assess the association between UR and HRV indices adjusted for age and length of hospitalization.ResultsA total of 78 patients met the inclusion criteria and 15 of them were readmitted within 14 days after discharge. The risk of UR was significantly higher in patients with lower levels of total power (OR = 1.39; 95% CI = 1.04-2.00), low frequency power (LF) (OR = 1.22; 95% CI = 1.03-1.49), high frequency power (HF) (OR = 1.27; 95% CI = 1.02-1.64), and lower ratios of low frequency power to high frequency power (LF/HF ratio) (OR = 1.96; 95% CI = 1.07-3.84).ConclusionThis is the first study to evaluate the association between frequency domain heart rate variability and the risk of UR in geriatric patients. Frequency domain heart rate variability indices measured on admission were significantly associated with increased risk of UR in geriatric patients. Additional studies are required to confirm the value and feasibility of using HRV indices on admission as a non-invasive tool to assist the prediction of UR in geriatric patients.

Welding of Alumina Using a Pulsed Dual-Beam CO2 Laser

Despite the many advantages of using lasers for welding ceramics (alumina in particular), cracks induced by the resulting and severe thermal stresses are often detrimental to weld quality and strength. While many factors contribute to the formation of these cracks, it is the inevitable and localized increase in temperature and the ensuing thermal stresses that usually cause the damage. To help avoid the use of a separate preheating step, while at the same time allowing for faster joining, a unique method of dual-beam laser welding was developed and qualitatively assessed. The approach outlined in this paper utilizes two beams split from a single, 500 W (1.5 kW peak) CO2 system to more gradually introduce the energy required to melt and bond alumina. The first or lead beam raises the local temperature just below the melting point, while the second beam introduces additional heat sufficient to melt and bond the samples. Using feed rates of 5.1 mm/s and beam separation distances ranging from 0.5 mm to 2.3 mm, clean and relatively straight weld geometries were observed at total power levels of approximately 250 W+. Relatively straight and uniform welds with considerable dross occurred at smaller beam separations and higher power levels. Uneven weld lines sans discernible cracks were observed at power levels below 206 W. Based on these preliminary observations, the two-beam approach was qualitatively shown to be capable of influencing and, in some instances, improving weld characteristics in terms of overall quality, dross, and crack formation.

Long-term effects of psychosocial factors of home and work on biomarkers of stress

Introduction The current study analyzed the relationship between psychosocial factors measured at baseline and heart rate variability (HRV) and salivary cortisol measured at baseline and again, six years later. Methods In 2002 and 2008, measurements of HRV and salivary cortisol at three time points were obtained from 70 healthy participants (48 women and 22 men). The associations between the psychosocial factors measured in 2002 and the dependent variables, HRV and salivary cortisol measured in 2002 and 2008, were examined using a series of repeated measures ANCOVAs. The dependent variables were as follows: the logarithmically transformed levels of total power (LnTP), high frequency power (LnHF), the ratio between low and high frequency power (LnLF/HF) and salivary cortisol (LnCortisol). Results For women, high social status was associated with high LnTP, high LnHF, and low LnLF/HF. In work, lack of control was associated with low LnTP, and lack of support was associated with an increased LnLF/HF ratio. For men, high social status was associated with low LnTP, low LnHF and high LnCortisol. Greater number of hours spent doing housework was associated with both low LnLF/HF and low LnCortisol, whereas a large imbalance between effort and reward was associated with low LnTP and high LnCortisol. Conclusion Despite the small sample size, this study demonstrated that psychosocial factors impact levels of activity in the allostatic systems.

Scalable video delivery over MIMO OFDM wireless systems using joint power allocation and antenna selection

This paper proposes a scalable video delivery transmission framework over multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless channels by combining power allocation and antenna selection schemes. The framework, which consists of independently decodable layers (3D ESCOT), an unequal error protection (UEP) channel coding structure, and an antenna selection scheme, provides more system error resilience even during periods of deep fading in wireless channels. A new algorithm is proposed to obtain the optimal power allocation and optimal transmission rate allocation among multiple layers, subject to constraints on the total transmission rate and the total power level. This proposed joint power allocation and antenna selection algorithm in MIMO OFDM systems enables us both to overcome the challenge of full channel state information (CSI) that was assumed to be necessary in the existing approaches and to utilize an estimated CSI from the receiver so as to achieve the optimal solution for a video bitstream in terms of its total expected distortion. Simulation results show that the proposed framework significantly improved system performance. Generally, as the wireless channel conditions change, the framework proposed can scale and transport the scaled video streams to receivers with smooth transitions in perceived quality.

Method for modifying axial fan’s guard grill and its impact on operating characteristics

This paper presents the impact of guard grill on aerodynamic integral characteristic, the spectrum of sound pressure level and total sound power level at four characteristic operating points of axial fans with standard guard grill, with optimized guard grill and without guard grill. The study of guard grill’s impact was conducted with measurements at integral level and local outflow velocity field of the axial fan without guard grill. The measurement results of the local outflow velocity field of the axial fan without guard grill at optimal operating point were used to model the optimized guard grill contour. The guard grill of axial fan has a significant impact on aerodynamic integral characteristic at free flow and mostly used operating region. The influence of guard grill is also characteristically reflected in the spectrum of sound pressure level via vortex shedding frequency and consequently at total sound power level of compared axial fans.

A nearly optimal amplify-and-forward relaying scheme for two-hop MIMO multi-relay networks

This letter proposes a nearly optimal amplify-and-forward (AF) relaying scheme for two-hop and half-duplex distributed relay networks with one source, one destination, and multiple relays, each equipped with multiple antennas. The system mutual information is first analyzed under the assumption of known channel state information (CSI), revealing that it is possible to maximize the information rate by designing properly the relay precoder as a block-diagonal matrix. Then, the maximum transmission rate issue is investigated under a total relay power constraint, leading to an optimal relaying scheme for moderate to high levels of total relay power. A simulation study is undertaken to show the effectiveness of the proposed solution.

Guard grill impact on aerodynamic integral and acoustic characteristics of an axial fan

This paper presents the impact of a guard grill design on the aerodynamic integral characteristic, the spectrum of sound pressure level and total sound power level. Four characteristic operating points of axial fans with a standard guard grill, with an optimized guard grill and without a guard grill were studied. Measurement results of the local outflow velocity vector of the axial fan without a guard grill at an optimal operating point were used to model the optimized guard grill contour. The guard grill of axial fan has a significant impact on the aerodynamic integral characteristic in the mostly used operating region. The influence of a guard grill is more characteristically reflected in the spectrum of the sound pressure levels via the vortex shedding frequency and consequently in the total sound power level of compared axial fans. Flow properties around grill wires were studied using an in-line cylinder cascade in the free velocity field at appropriate Reynolds numbers. Results are presented as power spectra of velocity fluctuations and spectra of sound pressure level and show good agreement with results of fan measurements

Corticosterone administration induces oxidative injury in skeletal muscle of broiler chickens

The present study had been conducted to explore the effect of corticosterone (CORT) on the induction of lipid peroxidation in skeletal muscle. The experimental chickens were subjected to 1 single s.c. injection of CORT (4 mg/kg of BW). Blood samples were obtained at the beginning and end of a 3-h experimental period. Muscle samples were obtained from musculus pectoralis major and musculus biceps femoris (BF) before and immediately after slaughter, and at 24- and 48-h time points postmortem. The result showed that plasma level of TBA reacting substances (TBARS) was significantly increased, whereas the activity of super-oxide dismutase was decreased after CORT injection. Plasma level of total antioxidant power, as reflected by the ferric reducing-antioxidant power, was increased by CORT administration. The preslaughter level of TBARS could be increased by CORT administration in pectoralis major. In contrast, although the preslaughter level of TBARS was not significantly changed by CORT administration in BF, the augmented TBARS level was detected at 48 h postmortem in BF of CORT chickens. During the period of storage, the concentrations of TBARS increased, whereas ferric reducing-antioxidant power level decreased over time regardless of treatment. In conclusion, the data suggest that elevated CORT due to preslaughter stress would affect the redox balance in skeletal muscle. The result suggested that the oxidative stability during storage of meat is associated with the alteration in muscle physiology induced by CORT administration.

The Perforated Panel Resonator with Flexible Tube Bundles and its Appliations

The sound absorptive mechanism and properties of the perforated panel resonator with flexible tube bundles are presented. Based upon that, some practical applications of the sound absorbing structure are introduced as follows. First of all, the perforated panel resonator with flexible tube bundles is used in designing a highly sound absorptive chamber, which is used as an audio-video laboratory. The acoustical performances of the chamber are presented. Second, the perforated panel resonator with flexible tube bundles is used in highly efficient duct silencer. The total noise level of axial fan source is attenuated to background noise level. Not only middle and high frequency noise is reduced, but also low frequency noise is suppressed considerably. Third, the perforated panel resonator with flexible tube bundles is used in a small-type centrifugal fan's casing treatments. The cut-off region of the centrifugal fan's casing is also acoustically treated. After the acoustical treatments, total sound power level of the fan is reduced obviously. Fourth, the perforated panel resonator with flexible tube bundles is used in designing the exhaust ducts and sound absorptive channel walls for an electrical transformer substation. The noise emitted from the transformer substation is reduced to surrounding background noise level.

Modeling and control of sound radiation by simply supported and cantilever beam coupled with smart material

In this paper forced vibration of the beam due to bonded piezoelectric patch is considered. When an external excitation is applied to the beam, it starts to vibrate, and the resulting acoustic response is predicted from the analytical model, which is based on Bernoulli-Euler theory of beam vibration. Analytical research of the sound radiation by a finite elastic beam is done for criteria based on minimal total sound power level. Helmholtz equation and inhomogeneous differential equation for beam transverse motion defines the solution to this problem. Such solutions were found for boundary conditions of simply supported and cantilever beams. In order to solve the task two analytical methods were used for simply supported beam. The solutions received by Fourier transform and Green functions approach give the very similar results, thus, proving methods reliability. At the case studies the exerted voltage, phase, location and piezoelectric actuator length are varied in order to establish their influence on noise attenuation.

Protective effect of α-lipoic acid in experimental spermatic cord torsion

Objective We investigated the effect of α-lipoic acid (LA) in rats that were subjected to torsion/detorsion of the spermatic cord in a comparative controlled experiment. Methods Forty-eight male Wistar rats, randomized in two groups, received intraperitoneal injections of LA (LA group; aqueous solution at 36 mg/kg of body weight per day) or equal volume of saline (control group) 21, 9, and 1 h before torsion of the spermatic cord. Rats in each group were distributed in four subgroups, each comprising six animals. All surgical procedures were performed under inhaled ether anesthesia. Ischemia was induced by 720-degree torsion of the spermatic cord for 3 h. The right testis was assessed through longitudinal scrotal incision. After each surgical procedure, scrotal incisions were closed with 4-0 nylon monofilament. Ipsilateral testes and arterial blood samples were collected at the end of ischemia and 1, 3, and 6 h after detorsion. Thiobarbituric acid-reactive substances and reduced glutathione levels (micromoles per gram of wet tissue) were assayed in testis. Total antioxidant power was measured in blood plasma. Results LA pretreatment promoted a significant decrease in testicular concentrations of thiobarbituric acid-reactive substances and simultaneously induced an increase in reduced glutathione concentrations at all time points studied. Plasma total antioxidant power levels increased significantly during reperfusion (T-1) in LA-treated rats compared with control rats. Conclusion LA administered before torsion of the spermatic cord showed significant protective effects against ischemia/reperfusion injury by decreasing lipid peroxidation and regulating testicular reduced glutathione and plasma total antioxidant power levels.