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Selected AbstractsImpact of varying pulse frequency and duration on muscle torque production and fatigue,MUSCLE AND NERVE, Issue 4 2007Chris M. Gregory PhD Abstract Neuromuscular electrical stimulation (NMES) involves the use of electrical current to facilitate contraction of skeletal muscle. However, little is known concerning the effects of varying stimulation parameters on muscle function in humans. The purpose of this study was to determine the extent to which varying pulse duration and frequency altered torque production and fatigability of human skeletal muscle in vivo. Ten subjects underwent NMES-elicited contractions of varying pulse frequencies and durations as well as fatigue tests using stimulation trains of equal total charge, yet differing parametric settings at a constant voltage. Total charge was a strong predictor of torque production, and pulse trains with equal total charge elicited identical torque output. Despite similar torque output, higher- frequency trains caused greater fatigue. These data demonstrate the ability to predictably control torque output by simultaneously controlling pulse frequency and duration and suggest the need to minimize stimulation frequency to control fatigue. Muscle Nerve, 2007 [source] Hospital Charges Attributable to a Primary Diagnosis of Infectious Diseases in Older Adults in the United States, 1998 to 2004JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 6 2008Aaron T. Curns MPH OBJECTIVES: To describe total and average hospital charges associated with infectious disease (ID) hospitalizations and specific ID categories and to estimate ID hospitalization rates in adults aged 65 and older in the United States from 1998 through 2004. DESIGN: Retrospective analysis of hospital discharge data obtained from the Nationwide Inpatient Sample for 1998 through 2004. SETTING: United States. PATIENTS: Older adults hospitalized in the United States from 1998 through 2004. MEASUREMENTS: Hospital charges and hospitalization rates for IDs described according to year, age group, sex, U.S. Census region, and ID category. Charges for non-ID hospitalizations were also described. Hospital charges were adjusted for inflation. RESULTS: From 1998 through 2004, total charges for ID hospitalizations exceeded $261 billion and accounted for 13% of all hospital charges for older adults. Total charges for ID hospitalizations increased from $31.4 billion in 1998 to $45.7 billion in 2004. The average annual ID hospital charge was lower than the average annual non-ID hospital charge during the study period ($21,342 vs $22,787, P<.001). The average annual rate for ID hospitalizations was 503 per 10,000 older adults, which remained stable during the study period. CONCLUSION: The total charges for ID hospitalizations and for all hospitalizations in older adults in the United States increased 45% and nearly 40%, respectively, during the 7-year study period, whereas the population of older adults grew by only 5%. Sustained increases of such magnitude will have major implications for the U.S. healthcare system as it prepares for the more than doubling of the older U.S. adult population during the first 30 years of this century. [source] Impact of a pediatric asthma clinical pathway on hospital cost and length of stay,PEDIATRIC PULMONOLOGY, Issue 3 2001April Wazeka MD Abstract This study sought to determine if a clinical pathway developed and executed by specialists in pediatric asthma would reduce hospital costs and length of stay (LOS). The study design was a retrospective, nonrandomized, controlled trial. Subjects were children aged 2,18 years (N,=,1,004) with a history of recurrent wheezing, hospitalized with a diagnosis of acute asthma exacerbation between 1995,1998 at the New York Hospital-Weill Cornell Medical Center and treated via the pathway, as well as a control group of 206 children ages 2,18 hospitalized for acute asthma exacerbation in 1994, the year prior to pathway implementation. Patients were treated via the pathway under the supervision of an asthma specialist. The pathway provided guidelines for: 1) frequency of patient assessment; 2) bronchodilator usage; 3) corticosteroid use; 4) laboratory evaluation; 5) vital signs, oxygen saturation, and peak flow measurements; 6) chest x-rays; 7) social work intervention; and 8) discharge planning. The main outcome measures were hospital length of stay, cost per hospitalization, nursing, medication, laboratory and radiology costs, and relapse rate. Total charges for admission and average LOS for 1995,1998 were calculated, and compared with 1994, the year preceding implementation of the pathway. LOS decreased from 4.2 days to 2.7 days (P,<,0.0001). The annual total charges for pediatric asthma admissions decreased from $2 million to $1.4 million (P,<,0.005). Nursing and laboratory costs showed a statistically significant decrease. Follow-up study at 8 months showed a readmission rate of 0.02%. The implementation of a pediatric asthma clinical pathway, directed by specialists, resulted in significantly decreased length of stay and overall cost, without an increased rate of readmission. Pediatr Pulmonol. 2001; 32:211,216. © 2001 Wiley-Liss, Inc. [source] Trends in Charges and Payments for Nonhospitalized Emergency Department Pediatric Visits, 1996,2003ACADEMIC EMERGENCY MEDICINE, Issue 4 2008Renee Y. Hsia MD Abstract Objectives:, To compare charges and payments for outpatient pediatric emergency visits across payer groups to provide information on reimbursement trends. Methods:, Total charges and payments for emergency department (ED) visits Medicaid/State Children's Health Insurance Program (SCHIP), privately insured, and uninsured pediatric patients from 1996 to 2003 using data from the Medical Expenditure Panel Survey. Average charges per visit and average payments per visit were also tracked, using regression analysis to adjust for changes in patient characteristics. Results:, While charges for pediatric ED visits rose over time, payments did not keep pace. This led to a decrease in reimbursement rates from 63% in 1996 to 48% in 2003. For all years, Medicaid/SCHIP visits had the lowest reimbursement rates, reaching 35% in 2003. The proportion of visits from children insured by Medicaid/SCHIP also increased over the period examined. In 2003, after adjustment, charges were $792 per visit from children covered by Medicaid/SCHIP, $913 for visits from uninsured children, and $952 for visits from privately insured children. Conclusions:, Reimbursements for outpatient ED visits in the pediatric population have decreased from the period of 1996 to 2003 in all payer groups: public (Medicaid/SCHIP), private, and the uninsured. Medicaid/SCHIP has consistently paid less per visit than the privately insured and the uninsured. Further research on the effects of these declining reimbursements on the financial viability of ED services for children is warranted. [source] Pt immobilization on TiO2 -embedded carbon nanofibers using photodepositionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2010S. Kim Abstract Currently, the use of fuel cell electrodes containing Pt catalysts has been limited due to technological problems in this system, primarily the system's high cost. The improvement of Pt catalyst use has been achieved by changes in the Pt immobilization method. In this study, we have studied Pt immobilization on carbon nanofiber composites using the photodeposition method. First, we prepared the carbon nanofibers, which were homogeneously embedded TiO2 using the electrospinning technology. These TiO2 -embedded carbon nanofiber composites (TiO2/CNFs) were then immersed in a Pt precursor solution and irradiated with UV light. The obtained Pt-deposited TiO2/CNFs contained Pt that was immobilized on the carbon nanofibers, and the Pt particle size was 2-5 nm. The XPS spectra showed that the amount of Pt increased with an increasing UV irradiation time. The current densities and total charge also increased with an increase in the UV irradiation time, possibly due to an increase of active specific area by finely dispersed Pt nanoparticles. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Voltammetric Studies of Parallel Electrode Processes Under Low Ionic Strength Conditions.ELECTROANALYSIS, Issue 7 2006Influence of Convection Abstract It is known that either a very strong enhancement or an almost complete depression of the height of one of two waves can be obtained when two analytes (one appropriately charged and one uncharged) are present in a quiet solution containing no supporting electrolyte. In this paper we examine whether these effects can be extended for solutions with forced convection. Three two-analyte mixtures were examined voltammetrically under conditions of no added supporting electrolyte and added convection. The first mixture (1,1,-ferrocenedimethanol and ferrocenesulfonate anion) changes its total charge from ,1 to +1 after electrooxidation of both components. Under all applied conditions, the introduction of convection caused an increase of both waves without changing the wave height ratio. A similar behavior was observed for the mixture of ferrocene and 1,1,-ferrocenedimethanol. For this system the total charge changes from 0 to +2. A substantial influence of convection on the ratio of two waves was found for the third mixture: ferrocene and ferrocenylmethyltrimethylammonium cation (total charge changes from +1 to +3). For this system the convection strongly depressed the migrational effects. The obtained experimental results were verified with simulations using software MIOTRAS. This software is capable of modeling diffusion, migration, convection and following homogenous reactions. The agreement between experiment and simulations was fairly good. [source] Identification and separation of DNA-hybridized nanocolloids by Taylor cone harmonicsELECTROPHORESIS, Issue 18 2009Xinguang Cheng Abstract A rapid (minutes) electrospray bead-based DNA hybridization detection technique is developed by spraying a mixture of hybridized and unhybridized silica nanocolloids. With proper far-field control by external electrodes, the trajectory of the ejected nanobeads from the electrospray is governed by specific harmonics of the Laplace equation, which select discrete polar angles along well-separated field maxima near the conducting Taylor cone. Due to Rayleigh fission and evaporation, beads of different size acquire different total charge after ejection and suffer different normal electrophoretic displacement such that they are ejected along well-separated field maxima and are deposited in distinct rings on an intersecting plane. As the hybridized DNA is of the same dimension as that of the nanocolloid, the nanocolloids are hence easily differentiated from the unhybridized ones. This technique is highly specific as the high shear stress in the microjet shears away any non-specifically bound DNA from the nanocolloid surface. [source] Binding of Oxovanadium(IV) to Tripeptides Containing Histidine and Cysteine Residues and Its Biological Implication in the Transport of Vanadium and Insulin-Mimetic CompoundsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2005Eugenio Garribba Abstract The complexation of VIVO ion with three tripeptides of biological importance containing L -histidine or L -cysteine (HisGlyGly, GlyGlyHis and GlyGlyCys) has been studied. This study was performed in aqueous solution by the combined application of potentiometric and spectroscopic (electronic absorption and EPR) techniques. The results indicate that these oligopeptides, if a ligand-to-metal molar ratio of 10 or 15 is used, can keep VIVO ion in solution until the deprotonation of the amide group with the donor set (NH2, CO, Nimax) for HisGlyGly or (COO,, CO) for GlyGlyHis and GlyGlyCys. In all the systems, at pH values around neutrality, a VOLH,2 species is formed with an (NH2, N,, N,, COO,) donor set for HisGlyGly, (NH2, N,, N,, Nim) for GlyGlyHis and (NH2, N,,N,, S,) for GlyGlyCys. These species, and those with onedeprotonated amide group coordinated to the VIVO ion, can be detected by EPR spectroscopy. The N,(amide) contribution to the hyperfine coupling constant along the z axis, Az, depends on the total charge of the donor atoms in the equatorial plane. The participation of albumin in the transport of vanadium and insulin-mimetic VIVO compounds is reconsidered based on these results. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Effects of stimulation frequency and pulse duration on fatigue and metabolic cost during a single bout of neuromuscular electrical stimulationMUSCLE AND NERVE, Issue 5 2010Julien Gondin PhD Abstract We have investigated the effects of stimulation frequency and pulse duration on fatigue and energy metabolism in rat gastrocnemius muscle during a single bout of neuromuscular electrical stimulation (NMES). Electrical pulses were delivered at 100 Hz (1-ms pulse duration) and 20 Hz (5-ms pulse duration) for the high (HF) and low (LF) frequency protocols, respectively. As a standardization procedure, the averaged stimulation intensity, the averaged total charge, the initial peak torque, the duty cycle, the contraction duration and the torque-time integral were similar in both protocols. Fatigue was assessed using two testing trains delivered at a frequency of 100 Hz and 20 Hz before and after each protocol. Metabolic changes were investigated in vivo using 31P-magnetic resonance spectroscopy (31P-MRS) and in vitro in freeze-clamped muscles. Both LF and HF NMES protocols induced the same decrease in testing trains and metabolic changes. We conclude that, under carefully controlled and comparable conditions, the use of low stimulation frequency and long pulse duration do not minimize the occurrence of muscle fatigue or affect the corresponding stimulation-induced metabolic changes so that this combination of stimulation parameters would not be adequate in the context of rehabilitation. Muscle Nerve, 2010 [source] Impact of varying pulse frequency and duration on muscle torque production and fatigue,MUSCLE AND NERVE, Issue 4 2007Chris M. Gregory PhD Abstract Neuromuscular electrical stimulation (NMES) involves the use of electrical current to facilitate contraction of skeletal muscle. However, little is known concerning the effects of varying stimulation parameters on muscle function in humans. The purpose of this study was to determine the extent to which varying pulse duration and frequency altered torque production and fatigability of human skeletal muscle in vivo. Ten subjects underwent NMES-elicited contractions of varying pulse frequencies and durations as well as fatigue tests using stimulation trains of equal total charge, yet differing parametric settings at a constant voltage. Total charge was a strong predictor of torque production, and pulse trains with equal total charge elicited identical torque output. Despite similar torque output, higher- frequency trains caused greater fatigue. These data demonstrate the ability to predictably control torque output by simultaneously controlling pulse frequency and duration and suggest the need to minimize stimulation frequency to control fatigue. Muscle Nerve, 2007 [source] On explicit solutions to the stationary axisymmetric Einstein-Maxwell equations describing dust disksANNALEN DER PHYSIK, Issue 10 2003C. Klein Abstract We review explicit solutions to the stationary axisymmetric Einstein-Maxwell equations which can be interpreted as disks of charged dust. The disks of finite or infinite extension are infinitesimally thin and constitute a surface layer at the boundary of an electro-vacuum. The Einstein-Maxwell equations in the presence of one Killing vector are obtained by using a projection formalism. This leads to equations for three-dimensional gravity where the matter is given by a SU(2,1)/S[U(1,1)× U(1)] nonlinear sigma model. The SU(2,1) invariance of the stationary Einstein-Maxwell equations can be used to construct solutions for the electro-vacuum from solutions to the pure vacuum case via a so-called Harrison transformation. It is shown that the corresponding solutions will always have a non-vanishing total charge and a gyromagnetic ratio of 2. Since the vacuum and the electro-vacuum equations in the stationary axisymmetric case are completely integrable, large classes of solutions can be constructed with techniques from the theory of solitons. The richest class of physically interesting solutions to the pure vacuum case due to Korotkin is given in terms of hyperelliptic theta functions. Harrison transformed hyperelliptic solutions are discussed. As a concrete example we study the transformation of a family of counter-rotating dust disks. To obtain algebro-geometric solutions with vanishing total charge which are of astrophysical relevance, three-sheeted surfaces have to be considered. The matter in the disk is discussed following Bi,ák et al. We review the ,cut and glue' technique where a strip is removed from an explicitly known spacetime and where the remainder is glued together after displacement. The discontinuities of the normal derivatives of the metric at the glueing hypersurface lead to infinite disks. If the energy conditions are satisfied and if the pressure is positive, the disks can be interpreted in the vacuum case as made up of two components of counter-rotating dust moving on geodesics. In electro-vacuum the condition of geodesic movement is replaced by electro-geodesic movement. As an example we discuss a class of Harrison-transformed hyperelliptic solutions. The range of parameters is identified where an interpretation of the matter in the disk in terms of electro-dust can be given. [source] Degree of blockiness of amide groups as indicator for difference in physical behavior of amidated pectinsBIOPOLYMERS, Issue 1 2006Stéphanie E. Guillotin Abstract Thickening and gelling properties of commercial amidated pectins depend on the degree of amidation and methyl-esterification, but also the distribution of these groups is of great importance. Methods have been developed during the last few years to determine the distribution of methyl esters over the pectic backbone. We applied the strategies developed for the analysis of high methyl-esterified pectins for studying the distribution of amide groups in amidated pectins. Low methyl-esterified amidated (LMA) pectins were digested before and after removal of methyl esters by an endo -polygalacturonase to determine the degree of blockiness of the substituents. The nature of the substituents (amide groups compared to methyl esters) did not modify the behavior of the enzyme. Oligomers released were separated by using high-performance anion exchange chromatography and pulsed amperometric detection (HPAEC,PAD) at pH 5. Fractions collected after on-line desalting were identified by using MALDI,TOF mass spectrometry. Oligomers were found to elute from the column as a function of their total charge. For the same overall charge and size, oligomers with methyl esters eluted before oligomers with amide groups. Both amide groups and methyl esters of the LMA pectins studied were found to be semirandomly distributed over the pectic backbone, but this may vary according to the amidation process used. © 2006 Wiley Periodicals, Inc. Biopolymers 82: 29,37, 2006 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Risk adjusted resource utilization for AMI patients treated in Japanese hospitalsHEALTH ECONOMICS, Issue 4 2007Edward Evans Abstract Though risk adjustment is necessary in order to make equitable comparisons of resource utilization in the treatment of acute myocardial infarction patients, there is little in the literature that can be practically applied without access to clinical records or specialized registries. The aim of this study is to show that effective models of resource utilization can be developed based on administrative data, and to demonstrate a practical application of the same models by comparing the risk-adjusted performance of the hospitals in our dataset. The study sample included 1748 AMI cases discharged from 10 large, private teaching hospitals in Japan, between 10 April 2001 and 30 June 2004. Explanatory variables included procedures (CABG and PCI), length of stay, outcome, patient demographics, diagnosis and comorbidity status. Multiple linear regression models constructed for the study were able to account for 66.5, 27.7, and 58.4% of observed variation in total charges, length of stay and charges per day, respectively. The performance of models constructed for this study was comparable to or better than performance reported by other studies that made use of explanatory variables extracted from clinical data. The use of administrative data in risk adjustment makes broad scale application of risk adjustment feasible. Copyright © 2006 John Wiley & Sons, Ltd. [source] Nationwide prevalence and prognostic significance of clinically diagnosable protein-calorie malnutrition in hospitalized inflammatory bowel disease patientsINFLAMMATORY BOWEL DISEASES, Issue 8 2008Geoffrey C. Nguyen MD Abstract Background Inflammatory bowel disease (IBD) patients are at increased risk of protein-calorie malnutrition. We sought to determine the prevalence of clinically diagnosable malnutrition among those hospitalized for IBD throughout the United States and whether this malnutrition influenced health outcomes. Methods We queried the Nationwide Inpatient Sample between 1998 and 2004 to identify admissions for Crohn's disease (CD) or ulcerative colitis (UC) and a representative sample of non-IBD discharges. We assessed the prevalence and predictors of malnutrition and its association with in-hospital mortality and resource utilization. Results The prevalence of malnutrition was greater in CD and UC patients than in non-IBD patients (6.1% and 7.2% versus 1.8%, P < 0.0001). The adjusted odds ratio for malnutrition among IBD admissions compared with non-IBD admissions was 5.57 [95% confidence interval (CI): 5.29,5.86]. More IBD discharges than non-IBD discharges with malnutrition received parenteral nutrition (26% versus 6%, P < 0.0001). There was increased likelihood of malnutrition among those with fistulizing CD (OR 1.65; 95% CI: 1.50,1.82) and among those who had undergone bowel resection (OR 1.37; 95% CI: 1.27,1.48). Malnutrition was associated with increased in-hospital mortality 3.49 (95% CI: 2.89,4.23), length of stay (11.9 days versus 5.8 days, P < 0.00001), and total charges ($45,188 versus $20,295, P < 0.0001). Conclusions Clinically apparent malnutrition is more frequent among IBD admissions than among non-IBD admissions. Its association with greater mortality and resource utilization may reflect more severe underlying disease that can lead to both malnutrition and worse outcomes. Nonetheless, diagnosable malnutrition may serve as a clinical marker of poor IBD prognosis in hospitalized patients. (Inflamm Bowel Dis 2008) [source] Hospital Charges Attributable to a Primary Diagnosis of Infectious Diseases in Older Adults in the United States, 1998 to 2004JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 6 2008Aaron T. Curns MPH OBJECTIVES: To describe total and average hospital charges associated with infectious disease (ID) hospitalizations and specific ID categories and to estimate ID hospitalization rates in adults aged 65 and older in the United States from 1998 through 2004. DESIGN: Retrospective analysis of hospital discharge data obtained from the Nationwide Inpatient Sample for 1998 through 2004. SETTING: United States. PATIENTS: Older adults hospitalized in the United States from 1998 through 2004. MEASUREMENTS: Hospital charges and hospitalization rates for IDs described according to year, age group, sex, U.S. Census region, and ID category. Charges for non-ID hospitalizations were also described. Hospital charges were adjusted for inflation. RESULTS: From 1998 through 2004, total charges for ID hospitalizations exceeded $261 billion and accounted for 13% of all hospital charges for older adults. Total charges for ID hospitalizations increased from $31.4 billion in 1998 to $45.7 billion in 2004. The average annual ID hospital charge was lower than the average annual non-ID hospital charge during the study period ($21,342 vs $22,787, P<.001). The average annual rate for ID hospitalizations was 503 per 10,000 older adults, which remained stable during the study period. CONCLUSION: The total charges for ID hospitalizations and for all hospitalizations in older adults in the United States increased 45% and nearly 40%, respectively, during the 7-year study period, whereas the population of older adults grew by only 5%. Sustained increases of such magnitude will have major implications for the U.S. healthcare system as it prepares for the more than doubling of the older U.S. adult population during the first 30 years of this century. [source] Low Back Pain in Older Adults: Are We Utilizing Healthcare Resources Wisely?PAIN MEDICINE, Issue 2 2006Debra K. Weiner MD ABSTRACT Objectives., 1) To examine recent change in prevalence and Medicare-associated charges for non-invasive/minimally invasive evaluation and treatment of nonspecific low back pain (LBP); and 2) to examine magnetic resonance imaging (MRI) utilization appropriateness in older adults with chronic low back pain (CLBP). Design., Two cross-sectional surveys of 1) national (1991,2002) and Pennsylvania (2000,2002) Medicare data; and 2) patients aged ,,65 years with CLBP. Setting., Outpatient data. Participants., Patients aged , 65 years with LBP. Measurements., Study 1: Outpatient national and Pennsylvania Part A Medicare data were examined for number of patients and charges for all patients, and for those with nonspecific LBP. Total number of visits and charges for imaging studies, physical therapy (PT), and spinal injections was also examined for Pennsylvania. Study 2: 111 older adults with CLBP were interviewed regarding presence of red flags necessitating imaging and history of having a lumbar MRI, neurogenic claudication (NC), and back surgery. Results., Study 1: Between 1991 and 2002, there was a 42.5% increase in total Medicare patients, 131.7% increase in LBP patients, 310% increase in total charges, and 387.2% increase in LBP charges. In Pennsylvania (2000,2002), there was a 5.5% increase in LBP patients and 33.2% increase in charges (0.2% for PT, 59.4% for injections, 41.9% for MRI/CT, and 19.3% for X rays). Study 2: None of the 111 participants had red flags and 61% had undergone MRIs (29% with NC, 24% with failed back surgery syndrome). Conclusion., LBP documentation and diagnostic studies are increasing in Medicare beneficiaries, and evidence suggests that MRIs may often be ordered unnecessarily. Injection procedures appear to account for a significant proportion of LBP-associated costs. More studies are needed to examine the appropriateness with which imaging procedures and non-invasive/minimally invasive treatments are utilized, and their effect on patient outcomes. [source] | ||||||||||||||||