bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling in vivo recovery of intracellular pH in muscle to provide a novel index of proton handling: Application to the diagnosis of mitochondrial myopathy
Authors: Chen J.T. , Taivassalo T. , Argov Z. , Arnold D.L. 
Published: October 2004

AbstractPost‐exercise recovery of intracellular pH (pHi) assessed using phosphorus magnetic resonance spectroscopy has not been previously evaluated in its entirety due to its complex time‐course and missing data points resulting from a transient loss of inorganic phosphate signal. By considering the transition from exercise to recovery as a step function input, pHi recovery was modeled based on the creatine‐kinase equilibrium, and the entire pHi recovery was characterized by calculating the time required for pHi recovery (tpHrec). Applying this methodology, normal subjects showed a strong linear correlation between phosphocreatine (PCr) half‐time and tpHrec (r = 0.90, P < 0.001). In mitochondrial myopathy (MM) patients with weakness in the limb examined, 9/10 had faster pHi recovery relative to PCr recovery; wide normal ranges from a control group which included deconditioned subjects resulted in 7 of those 10 patients having otherwise normal recovery indices. Therefore, modeling pHi recovery allows characterization of the entire pHi recovery and detects altered proton handling in MM patients, including those with otherwise normal recovery indices. Magn Reson Med 46:870–878, 2001. © 2001 Wiley‐Liss, Inc.
Polyunsaturated fatty acids mapping by 1H MR‐chemical shift imaging
Authors: Lunati Ernesto , Farace Paolo , Nicolato Elena , Righetti Claudia , Marzola Pasquina , Sbarbati Andrea , Osculati Francesco 
Published: October 2004

AbstractParametric mapping of polyunsaturated fatty acids (PUFA) distribution in adipose tissues was obtained by 1H chemical shift imaging (CSI). A matrix of spectra, acquired with a CSI sequence having two spatial and one spectroscopic dimension, was processed with ad hoc algorithms. The protocol was applied to phantoms containing different lipids in which the degree of polyunsaturation was determined by high‐resolution nuclear magnetic resonance (NMR). High correlation (R2 = 0.998) between degrees of polyunsaturation given by our protocol and that measured by high‐resolution NMR was found. The thoracic region of rats was also examined. Parametric maps of the polyunsaturation degree were obtained for the brown adipose tissue and the white axillary fat: the first deposit was found more polyunsaturated than the second. Finally, in vivo mapping of the inguinal region of the rat was produced that allowed us to individuate PUFA‐rich areas in adipose tissue. This work demonstrates the feasibility of PUFA imaging in vivo. Magn Reson Med 46:879–883, 2001. © 2001 Wiley‐Liss, Inc.
A qualitative test of the balloon model for BOLD‐based MR signal changes at 3T
Authors: Mildner Toralf , Norris David G. , Schwarzbauer Christian , Wiggins Christopher J. 
Published: October 2004

AbstractThe aim of this study was to adapt the balloon model for BOLD‐based MR signal changes to a magnetic field strength of 3T and to examine its validity. The simultaneous measurement of BOLD and diffusion‐weighted BOLD responses was performed. The amplitude of the BOLD peak was found to be similar for all subjects when a short visual stimulus of 6 sec was used. The rise‐time to the BOLD peak and the shape and depth of the poststimulus undershoot varied significantly. A fit of the experimental BOLD responses was found to be possible by use of parameters within a reasonable physiological range. The relations between these parameters and their influence on the modeled BOLD responses is discussed. A prediction of the balloon model is the occurrence of a BOLD overshoot, i.e., a lag between the changes of the blood volume and the blood flow after the start of the stimulation. Experimental evidence for the existence of a BOLD overshoot is presented. Magn Reson Med 46:891–899, 2001. © 2001 Wiley‐Liss, Inc.
Dual contrast TrueFISP imaging for left ventricular segmentation
Authors: Merrifield Robert , Keegan Jennifer , Firmin David , Yang Guang‐Zhong 
Published: October 2004

AbstractBased on varying tissue contrasts at different RF flip angles, a new TrueFISP imaging strategy for cardiac function measurement is presented. A single breath‐hold dual RF flip angle cine multi‐slice TrueFISP imaging sequence was implemented which provides a significant increase in signal contrast between blood and myocardium. The increase in image contrast combined with different characteristics in RF response facilitates the delineation of cardiovascular borders. Based on this imaging strategy it is demonstrated how a simple 2D histogram clustering algorithm can be used for the fully automatic segmentation of the left ventricular (LV) blood pool. The method is validated with data acquired from 10 asymptomatic subjects, and the results are shown to be comparable to that of manual delineation by experienced observers. Magn Reson Med 46:939–945, 2001. © 2001 Wiley‐Liss, Inc.
Two‐pedal ergometer for in vivo MRS studies of human calf muscles
Authors: Francescato Maria Pia , Cettolo Valentina 
Published: October 2004

AbstractThis article describes an ergometer that enables human subjects to exercise one or both limbs while 31P NMR spectra are obtained. Two independent pedals, equipped with position and force transducers, were mounted on the ergometer in order to calculate mechanical work performance. First, the effect of the magnetic field upon the signal coming from the transducers was investigated. Then the ergometer was tested by performing a series of steady‐state exercises of increasing intensity. Experimental data showed that actual mechanical power ranged from 1.5 ± 0.2 W to 11.0 ± 1.6 W, while the corresponding oxygen consumption increased from 0.28 ± 0.04 l/min at rest to 0.48 ± 0.10 l/min at the highest load, and the PCr/(PCr+Pi) ratio, as calculated from the 31P spectra, decreased from 0.94 ± 0.01 at rest to 0.73 ± 0.04. These results are consistent with the values reported in the literature and show that this ergometer, which is easy to use, is suitable for in vivo spectroscopy research when metabolic steady‐state conditions are required. Magn Reson Med 46:1000–1005, 2001. © 2001 Wiley‐Liss, Inc.
Temperature dosimetry using MR relaxation characteristics of poly(vinyl alcohol) cryogel (PVA‐C)
Authors: Lukas L.A. , Surry K.J.M. , Peters T.M. 
Published: October 2004

AbstractHyperthermic therapy is being used for a variety of medical treatments, such as tumor ablation and the enhancement of radiation therapy. Research in this area requires a tool to record the temperature distribution created by a heat source, similar to the dosimetry gels used in radiation therapy to record dose distribution. Poly(vinyl alcohol) cryogel (PVA‐C) is presented as a material capable of recording temperature distributions between 45 and 70°C, with less than a 1°C error. An approximately linear, positive relationship between MR relaxation times and applied temperature is demonstrated, with a maximum of 16.3 ms/°C change in T1 and 10.2 ms/°C in T2 for a typical PVA‐C gel. Applied heat reduces the amount of cross‐linking in PVA‐C, which is responsible for a predictable change in T1 and T2 times. Temperature distributions in PVA‐C volumes may be determined by matching MR relaxation times across the volumes to calibration values produced in samples subjected to known temperatures. Factors such as thermotolerance, perfusion effects, and thermal conductivity of PVA‐C are addressed for potentially extending this method to modeling thermal doses in tissue. Magn Reson Med 46:1006–1013, 2001. © 2001 Wiley‐Liss, Inc.
k‐Space weighted least‐squares algorithm for accurate and fast motion extraction from magnetic resonance navigator echoes
Authors: Nguyen Thanh D. , Wang Yi , Watts Richard , Mitchell Ian 
Published: October 2004

AbstractNavigator echoes provide an effective method to monitor physiological motion, allowing motion artifacts to be suppressed by modifying the data acquisition accordingly. The displacement can be measured directly from the navigator phase using an algorithm suggested by Ahn and Cho (IEEE Trans Med Imaging 1987;MI‐6:32–36). Although computationally efficient, it is susceptible to noise, particularly contributions from points at the edges of k‐space. A k‐space weighted least‐squares (kLS) algorithm is proposed which fits a straight line to the motion‐induced phase shift. The linear fit is weighted strongly to high SNR points near the k‐space center and only weakly to the poor SNR points at the edges of k‐space. This algorithm was found to be as efficient as Ahn's algorithm but more robust against noise. Magn Reson Med 46:1037–1040, 2001. © 2001 Wiley‐Liss, Inc.
Recasting Intractable Policy Issues: The Wider Implications of The Netherlands Civil Aviation Controversy
Authors: van Eeten Michel J.G. 
Published: October 2004

AbstractThe explosive growth of civil aviation is among the most difficult issues in transportation policy, and nowhere are the fundamental economic and environmental challenges it poses more apparent than in airport expansion. Conventional policy analyses have ineffectively handled these problems, characterized by uncertainty, complexity, and polarization. Increasingly, policy analysts and public managers depend on stakeholder involvement to recast intractable issues into a more tractable format. This article describes a method that supports this recasting process through analysis of stakeholders' policy arguments; and in so doing contributes to the increasing literature on recasting intractable policy issues and to the recent discussion of Q‐methodology in the Journal of Policy Analysis and Management. The method is applied in a policy analysis of the controversy over the expansion of Amsterdam's Schiphol Airport. The analysis, which was under‐taken on behalf of the Dutch government and which has wider implications, leads to a new agenda for transportation policy by uncovering and addressing a fuller range of alternatives that move beyond the current polarization and allow the problem to be redefined more tractably. © 2001 by the Association for Public Policy Analysis and Management.
Packaging Support for Low‐Income Families: Policy Variation across the United States
Authors: Meyers Marcia K. , Gornick Janet C. , Peck Laura R. 
Published: October 2004

AbstractThis paper addresses a gap in state‐level comparative social policy research by analyzing policies that support low‐income families with children. Variation in state policy “packages” is measured by considering three characteristics of 11 social programs. Individual measures of policy are found to be weakly and inconsistently inter‐correlated at the state level, but when cluster analysis is used to analyze multiple dimensions simultaneously, five clusters or regime types are identified that have distinctive policy approaches. These range from the most minimal provisions, to conservative approaches emphasizing private responsibility, to integrated approaches that combine generous direct assistance with employment support and policies that enforce family responsibility. A comparison of a subset of programs at two points in time (1994 and 1998) suggests that states made substantial changes in cash assistance and taxation policies after the 1996 federal welfare reforms. The magnitude and direction of these changes remained consistent with the state clusters identified in 1994. © 2001 by the Association for Public Policy Analysis and Management.
Location‐Efficient Mortgages: Is the Rationale Sound?
Authors: Blackman Allen , Krupnick Alan 
Published: October 2004

AbstractLocation efficient mortgage (LEM) programs are an increasingly popular approach to combating urban
sprawl. LEMs allow families who want to live in densely populated, transit‐rich communities to obtain a
larger mortgage with a smaller down payment than traditional underwriting guidelines allow. LEMs are premised on
the proposition that homeowners in such “location‐efficient” areas can safely be allowed to
breach underwriting guidelines designed to prevent mortgage default because they have lower than average
automobile‐related transportation expenses and more income available for mortgage payments. This paper
employs records of more than 8000 FHA‐insured mortgages matched with data on various measures of location
efficiency to test this proposition. The results suggest that it does not hold and that LEMs—like other
low‐down‐payment mortgage programs—will raise mortgage default rates. This cost must be
weighed against any potential anti‐sprawl benefits LEMs may have. © 2001 by the Association for
Public Policy Analysis and Management.
Assessing OSHA Performance: New Evidence from the Construction Industry
Authors: Weil David 
Published: October 2004

AbstractThe determinants of OSHA performance can be examined by breaking the regulatory process into three elements
relating to enforcement, compliance behavior, and the adequacy of standards in addressing safety outcomes. This
paper develops and applies this framework to the U.S. construction industry during the period 1987 to 1993.
Enforcement activity among the firms in the sample was substantial, with firms facing a high probability of
annual inspection. But, despite this significant enforcement effort, inspections have a modest effect on firm
compliance with OSHA standards. Finally, the health and safety standards cited most frequently diverge from the
major sources of fatalities and injuries on construction projects. These results suggest that historic
enforcement policies toward construction make less sense as OSHA moves into its fourth decade of operation. More
generally, the paper illustrates the problem of focusing enforcement resources on large, high&hyphen;profile
companies even though they often are not the major source of regulatory problems in an established area of
public policy intervention. &copy; 2001 by the Association for Public Policy Analysis and Management.
Moving Up, Moving Out, or Going Nowhere? A Study of the Employment Patterns of Young Women and the Implications for Welfare Mothers
Authors: Pavetti LaDonna , Acs Gregory 
Published: October 2004

AbstractConventional wisdom holds that women on welfare will be better off in the long run if they take a job, even
if it means initially having less money to spend on their and their children's needs. Underlying this
thinking is the belief that women who take low‐paying jobs will eventually move up to higher paying jobs
either with their current employer or by changing employers. This paper examines the employment transitions of
young women focusing on the likelihood that women who turn to the welfare system for support will make the
transition from low‐paying to high‐paying jobs. The data are drawn from the National Longitudinal
Survey of Youth (NLSY). Based on the experiences of women who never received welfare, an estimated
one‐quarter of young women who received welfare could be firmly established in jobs paying more than
$9.50 an hour by ages 26 and 27. An additional 40 percent would work steadily but in low‐paying
jobs, and more than one‐third would work only sporadically. © 2001 by the Association for Public
Policy Analysis and Management.
Novel fixed‐site–carrier polyvinylamine membrane for carbon dioxide capture
Authors: Kim Taek‐Joong , Li Baoan , Hägg May‐Britt 
Published: October 2004

AbstractFixed‐site–carrier membranes were prepared for the facilitated transport of CO2 by casting polyvinylamine (PVAm) on various supports, such as poly(ether sulfone) (PES), polyacrylonitrile (PAN), cellulose acetate (CA), and polysulfone (PSO). The cast PVAm on the support was crosslinked by various methods with glutaraldehyde, hydrochloric acid, sulfuric acid, and ammonium fluoride. Among the membranes tested, the PVAm cast on polysulfone and crosslinked by ammonium fluoride showed the highest selectivity of CO2 over CH4 (>1000). The permeance of CO2 was then measured to be 0.014 m3 (STP)/(m2 bar h) for a 20 μm thick membrane. The effect of the molecular weight of PVAm and feed pressure on the permeance was also investigated. The selectivity increased remarkably with increasing molecular weight and decreased slightly with increased pressure in the range of 1 to 4 bar. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4326–4336, 2004
How pediatricians manage asthma in Thailand
Authors: Vichyanond Pakit , Hatchaleelaha Sombat , Jintavorn Viravich , Kerdsomnuig Sirikul 
Published: October 2004

AbstractCurrently, there is no existing information regarding prescribing practices for the management of childhood asthma among pediatricians in Thailand. In order to evaluate the management standards for childhood asthma in Thailand, 400 self‐administered questionnaires were randomly mailed to nonacademic pediatricians throughout Thailand, asking questions about their preferences in the treatment of childhood asthma.One hundred and seventy‐four of these 400 questionnaires were returned (a response rate of 43.5%). Data were analyzed using the descriptive module of the Epi‐info 6 program. For acute asthma, 17% of the respondents used objective measures such as peak flow meters in assessing asthma severity and severity of acute asthma attacks. The drug of first choice for treating acute attacks was a nebulized beta‐agonist q 20 min (81.8%). Although 93% indicated that they had used theophylline for treating acute attacks, most would reserve the drug for patients with severe symptoms. Corticosteroids were reserved for those with severe attacks (91.7% both for clinic and for in‐hospital settings). Hydrocortisone was the most preferred corticosteroid preparation (59.8%). Ninety‐seven percent used antibiotics in treating acute asthma, but only with appropriate indications. For chronic asthma, a strong preference was observed for oral beta‐agonists as the bronchodilator of choice (88%). For moderately severe asthmatics, theophylline was still preferred by 41% of the responders. Among prophylactic agents, ketotifen was the most favored drug (90.4%), whereas inhaled steroids and cromolyn were chosen by 9.6% and 2.4%, respectively. Eighty‐five percent indicated that they would prescribe prophylactic agents for 1 year or less. Forty‐two percent never considered allergy evaluation as a part of a workup for childhood asthma.Certain prescribing practices of childhood asthma management in Thailand were observed among pediatricians, i.e., 1) low frequency of using objective measures in assessing asthma severity among pediatricians; 2) frequent use of theophylline and antibiotics in the treatment of acute asthma; 3) late introduction of corticosteroids in treating acute asthma; 4) preference for oral bronchodilators; and 5) preference of ketotifen as the prophylactic drug of choice. This survey provides baseline data and will aid in the evaluation of management guidelines for childhood asthma in Thailand. Pediatr Pulmonol. 2001; 32:109–114. © 2001 Wiley‐Liss, Inc.
Safety of aerosolized INS 365 in patients with mild to moderate cystic fibrosis: Results of a phase I multi‐center study
Authors: Noone Peadar G. , Hamblett Nicole , Accurso Frank , Aitken Moira L. , Boyle Michael , Dovey Mark , Gibson Ron , Johnson Craig , Kellerman Don , Konstan Michael W. , Milgram Laura , Mundahl Jean , Retsch‐Bogort George , Rodman David , Williams‐Warren Judy , Wilmott Robert W. , Zeitlin Pam , Ramsey Bonnie 
Published: October 2004

AbstractCystic fibrosis (CF) is characterized by defective cystic fibrosis transmembrane regulator (CFTR) expression and function, associated with abnormal ion transport and mucociliary clearance, and clinical lung disease. Triphosphate nucleotides such as uridine‐5′‐triphosphate (UTP) and INS 365, may be useful for CF through actions, mediated via P2Y2 extracellular receptors, on chloride and liquid secretion, and ciliary beat frequency. INS 365 may offer chemical stability advantages over UTP. In a randomized, double‐blind, multicenter phase I study, we studied the safety and maximally tolerated dose of escalating, single doses of aerosolized INS 365, in adult and pediatric patients with mild to moderate CF lung disease (FEV1 ≥ 45% predicted). In four successive dose cohorts of adult patients (n = 12 per cohort, age ≥ 18 years) and four successive pediatric dose cohorts (n = 12 per cohort, age 5–12 years), patients were randomized 3:1 active/placebo (0.9% saline) to evaluate doses of 20, 40, 80, and 100 mg INS 365 delivered by nebulizer (Pari Star™). Sputum was collected pre‐ and post‐dosing to obtain preliminary results on clinical efficacy. After each dose cohort, a Data Safety Monitoring Committee (DSMC) reviewed the data.Forty‐eight adult and 36 pediatric patients completed the protocol (up to 100 mg for adults, 80 mg for pediatric patients). The predominant adverse events were cough, wheezing, chest tightness, and a decrease in FEV1 (occurring in 8/48 adults, and 5/36 pediatric patients), which occurred predominantly in the 80‐mg and 100‐mg dose cohorts. Though a few adult patients had a tendency to increase sputum production, there was little consistent effect noted on sputum production in this acute, single‐dose study.The data suggest that aerosolized INS 365 is safe when delivered at single doses of up to 40 mg in adults and children with CF, but that higher doses are unlikely to be tolerated. Pediatr Pulmonol. 2001; 32:122–128. © 2001 Wiley‐Liss, Inc.
Canine prostate induces new bone formation in mouse calvaria: A model of osteoinduction by prostate tissue
Authors: LeRoy Bruce E. , Bahnson Robert R. , Rosol Thomas J. 
Published: October 2004

AbstractBACKGROUNDOsteoblastic metastases are common in patients with advanced prostate cancer. The pathophysiology of the new bone formation at metastatic sites is not currently known, but it is hypothesized that growth factors secreted by the prostate may be involved. Unfortunately, most rodent models of prostate cancer with metastasis to bone are osteolytic and not osteoblastic. Significant osteolysis by tumor cells at metastatic sites may also lead to fractures or bone instability. Misinterpretation of new periosteal bone due to bone instability as tumor‐cell osteoinduction is another disadvantage of the osteolytic models. To circumvent these problems, we have developed a model system of new bone formation in the calvaria of nude mice stimulated by normal canine prostate tissue.METHODSCollagenase‐digested normal prostate tissue was implanted adjacent to the calvaria of nude mice. Calvaria were examined at 2 weeks post‐implantation for changes in the bone microenvironment by histology, calcein uptake at sites of bone mineralization, and tartrate‐resistant acid phosphatase staining for osteoclasts.RESULTSThe prostate tissue remained viable and induced abundant new woven bone formation on the adjacent periosteal surface. In some cases new bone formation also was induced on the distant or concave calvarial periosteum. The new bone stained intensely with calcein, which demonstrated mineralization of the bone matrix. The new bone formation on prostate‐implanted calvaria significantly increased (1.7‐fold) the thickness of the calvaria compared with control calvaria. New bone formation was not induced in calvaria of mice implanted with normal canine kidney, urinary bladder, spleen, or skeletal muscle tissue, or mice with surgically‐induced disruption of the periosteum. Osteoclast numbers in the medullary spaces and periosteum of calvaria were mildly increased (61%) in mice with implanted prostate tissue.CONCLUSIONSThis animal model will be useful for investigating the roles of prostate‐derived growth factors on new bone formation in vivo. Prostate 50: 104–111, 2002. © 2002 Wiley‐Liss, Inc.