bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural history of cardiac involvement in geleophysic dysplasia
Authors: Scott A. , Yeung S. , Dickinson D.F. , Karbani G. , Crow Y.J. 
Published: December 2004

AbstractGeleophysic dysplasia is an autosomal recessive short‐limbed, dysmorphic syndrome. The condition is frequently associated with cardiac valvular disease, which may result in secondary hypertrophy and cardiac failure. We describe two distantly related Pakistani children with classical features of geleophysic dysplasia. Pulmonary stenosis was recognized in both within a few months of birth. The younger child shows no signs of cardiac decompensation at the age of 7 years whilst her older cousin has developed a significant pulmonary gradient requiring surgical intervention in the second decade of life. The natural history of his disorder highlights that the cardiac involvement seen in apparently stable forms of geleophysic dysplasia is frequently progressive. © 2004 Wiley‐Liss, Inc.
Quantitative analysis of docetaxel in human plasma using liquid chromatography coupled with tandem mass spectrometry
Authors: Kuppens I. E. L. M. , van Maanen M. J. , Rosing H. , Schellens J. H. M. , Beijnen J. H. 
Published: December 2004

AbstractAn assay for the quantitative determination of docetaxel in human plasma is described. Docetaxel was extracted from the matrix using liquid–liquid extraction with ter‐butylmethylether, followed by high‐performance liquid chromatographic analysis using an alkaline eluent. Paclitaxel was used as internal standard. Positive ionization electrospray tandem mass spectrometry was performed for selective and sensitive detection. The method was validated according to the FDA guidelines on bioanalytical method validation. The validated range for docetaxel was from 0.25–1000 ng/mL using 200 µL plasma aliquots. The method requires only a limited volume (200 µL) of human plasma and the method can be applied in studies requiring a low lower limit of quantitation of 0.25 ng/mL. The assay was applied successfully in several clinical and pharmacological studies with docetaxel. Copyright © 2004 John Wiley & Sons, Ltd.
Forced Intercalation Probes (FIT Probes): Thiazole Orange as a Fluorescent Base in Peptide Nucleic Acids for Homogeneous Single‐Nucleotide‐Polymorphism Detection
Authors: Köhler Olaf , Jarikote Dilip Venkatrao , Seitz Oliver 
Published: December 2004

AbstractFluorescent base analogues in DNA are versatile probes of nucleic acid–nucleic acid and nucleic acid–protein interactions. New peptide nucleic acid (PNA) based probes are described in which the intercalator dye thiazole orange (TO) serves as a base surrogate. The investigation of six TO derivatives revealed that the linker length and the conjugation site decided whether a base surrogate conveys sequence‐selective DNA binding and whether fluorescence is increased or decreased upon single‐mismatched hybridization. One TO derivative conferred universal PNA–DNA base pairing while maintaining duplex stability and hybridization selectivity. TO fluorescence increased up to 26‐fold upon hybridization. In contrast to most other probes, in which fluorescence is invariant once hybridization had occurred, the emission of TO‐containing PNA probes is attenuated when forced to intercalate next to a mismatched base pair. The specificity of DNA detection is therefore not limited by the selectivity of probe–target binding and a DNA target can be distinguished from its single‐base mutant under nonstringent hybridization conditions. This property should be of advantage for real‐time quantitative PCR and nucleic acid detection within living cells.
Hierarchical, model‐based merging of multiple fragments for improved three‐dimensional segmentation of nuclei
Authors: Lin Gang , Chawla Monica K. , Olson Kathy , Guzowski John F. , Barnes Carol A. , Roysam Badrinath 
Published: December 2004

AbstractBackgroundAutomated segmentation of fluorescently labeled cell nuclei in three‐dimensional confocal images is essential for numerous studies, e.g., spatiotemporal fluorescence in situ hybridization quantification of immediate early gene transcription. High accuracy and automation levels are required in high‐throughput and large‐scale studies. Common sources of segmentation error include tight clustering and fragmentation of nuclei. Previous region‐based methods are limited because they perform merging of two nuclear fragments at a time. To achieve higher accuracy without sacrificing scale, more sophisticated yet computationally efficient algorithms are needed.MethodsA recursive tree‐based algorithm that can consider multiple object fragments simultaneously is described. Starting with oversegmented data, it searches efficiently for the optimal merging pattern guided by a quantitative scoring criterion based on object modeling. Computation is bounded by limiting the depth of the merging tree.ResultsThe proposed method was found to perform consistently better, achieving merging accuracy in the range of 92% to 100% compared with our previous algorithm, which varied in the range of 75% to 97%, even with a modest merging tree depth of 3. The overall average accuracy improved from 90% to 96%, with roughly the same computational cost for a set of representative images drawn from the CA1, CA3, and parietal cortex regions of the rat hippocampus.ConclusionHierarchical tree model‐based algorithms significantly improve the accuracy of automated nuclear segmentation without sacrificing speed. © 2004 Wiley‐Liss, Inc.
Chemical cytometry for monitoring metabolism of a Ras‐mimicking substrate in single cells
Authors: Arkhipov Sergey N. , Berezovski Maxim , Jitkova Julia , Krylov Sergey N. 
Published: December 2004

AbstractBackgroundChemical cytometry is an emerging technology that analyzes chemical contents of single cells by means of capillary electrophoresis or capillary chromatography. It has a potential to become an indispensable tool in analyses of heterogeneous cell populations such as those in tumors. Ras oncogenes are found in 30% of human cancers. To become fully functional products, oncogenic Ras proteins require at least three posttranslational modifications: farnesylation, endoproteolysis, and carboxyl‐methylation. Therefore, enzymes that catalyze the three reactions, farnesyltransferase (FTase), endoprotease (EPase), and methyltransferase (MTase), are considered highly attractive therapeutic targets. In this work, we used chemical cytometry to study the metabolism of a pentapeptide substrate that can mimic Ras proteins with respect to their posttranslational modifications in solution.MethodsMouse mammary gland tumor cells (4T1) and mouse embryo fibroblasts (NIH3T3) were incubated with a fluorescently labeled pentapeptide substrate, 2′,7′‐difluorofluorescein‐5‐carboxyl‐Gly‐Cys‐Val‐Ilu‐Ala. Cells were washed from the substrate and resuspended in phosphate buffered saline. Uptake of the substrate by the cells was monitored by laser scanning confocal microscopy. Single cells were injected into the capillary, lysed, and subjected to capillary electrophoresis. Fluorescent metabolic products were detected by laser‐induced fluorescence and compared with products obtained by the conversion of the substrate by FTase, EPase, and MTase in solution. Co‐sampling of single cells with the in‐vitro products was used for such comparison.ResultsConfocal microscopy data showed that the substrate permeated the plasma membrane and clustered in the cytoplasm. Further capillary electrophoresis and chemical cytometry analyses showed that the substrate was converted into three fluorescently labeled products, two of which were secreted in the culture medium and one remained in the cells. The intracellular product was present at approximately 100,000 molecules per cell. The three metabolic products of the substrate were found to be different from the products of its processing by FTase, EPase, and MTase in solution.ConclusionsThis is the first report of chemical cytometry in the context of Ras‐signaling studies. The chemical cytometry method used in this work will find applications in the development of suitable peptide substrates for monitoring enzyme activities in single cells. © 2004 Wiley‐Liss, Inc.
Risk of type 1 diabetes in childhood and maternal age at delivery, interaction with ACPI and sex
Authors: Bottini N. , Meloni G. F. , Lucarelli P. , Amante A. , Saccucci P. , Gloria‐Bottini F. , Bottini E. 
Published: December 2004

AbstractBackgroundWe have investigated the possible role of ACP1 (also known as cLMWPTP: cytosolic low molecular weight phosphotyrosine phosphatase), a highly polymorphic enzyme involved in signal transduction of T‐cell receptor, insulin receptor and other growth factors in the relationship between maternal age at delivery and risk of type 1 diabetes in the offspring.MethodsOne hundred and eighty‐nine consecutive children with type 1 diabetes (TIDM) diagnosed at the Department of Pediatrics of the University of Sassari (Sardinia) were studied. A control sample of 5460 consecutive newborns from the same population was also studied.ResultsMaternal age at birth of children with type 1 diabetes has shifted towards high values. There is also an effect of birth order on the susceptibility to type 1 diabetes, which is independent of that due to maternal age. The proportion of low activity ACPl genotypes is much higher among children born from older mothers than among diabetic children born from relatively young mothers. There is a significant effect of sex, maternal age, sex–ACPl two‐way interaction and sex–ACP1–maternal age three‐way interaction on the age at diagnosis of diabetes.ConclusionsThe present data confirm the strong association between maternal age at delivery and risk of type 1 diabetes in the child. In addition, our analysis suggests a complex interaction among maternal age, sex of infant and ACP1 concerning age at diagnosis of diabetes. Thus, risk and clinical course of type 1 diabetes seem to be dependent on both maternal environment during intrauterine development and foetal genetic factors. Copyright © 2004 John Wiley & Sons, Ltd.
Design and development of a scale measuring fear of complications in type 1 diabetes
Authors: Taylor Emily P. , Crawford John R. , Gold Ann E. 
Published: December 2004

AbstractBackgroundThere are many determinants of glycaemic control in patients with type 1 diabetes. Patients with type 1 diabetes and poor glycaemic control have been reported as being more likely to have a greater fear of hypoglycaemia. The relationship between fear of diabetes‐related complications and glycaemic control is unclear, and therefore a brief measure of fear of diabetes complications was developed.MethodsA questionnaire was designed, comprising items relating to general fears, specific fears (e.g. blindness, kidney problems, heart disease), lifestyle fears, fear of hypoglycaemia and weight gain. The questionnaire was piloted on 147 outpatients with type 1 diabetes, along with other measures such as the Hypoglycaemia Fear Survey, the Hospital Anxiety and Depression Scales, the Coping with Health, Injuries and Problems Scale and the Eysenck Personality Questionnaire.ResultsFactor analysis was carried out on the 30 items and, after rotation, 15 emerged as loading heavily on the first factor. Factor analysis was rerun on these 15 items and the first factor accounted for 56% of the total variance. This factor remained invariant when the scale was split randomly and by age and gender. The reliability of the scale (α) was 0.94. The scale did not correlate with any demographic variables but did with measures of negative affectivity (HADS anxiety = 0.34, p < 0.001; Depression = 0.24, p < 0.004), the Hypoglycaemia fear survey worry Scale (0.44, p < 0.001), presence of complications (0.17, p < 0.04) and number of complications (0.28, p < 0.001).ConclusionsThese results indicate that the scale identifies a fear that is moderately related to the presence of complications and general negative affectivity but which is a uniquely diabetes‐related emotion. Copyright © 2004 John Wiley & Sons, Ltd.
Alkaline Fuel Cells
Authors: Gülzow E. 
Published: December 2004

AbstractAlkaline fuel cells may become an important element in pollution free energy conversion. In the literature most papers in the field of low temperature fuel cells are concerned with polymer electrolyte fuel cells. However, there are still a lot of research groups and companies working on alkaline fuel cells.The advantages and disadvantages of AFCs are presented. The main technical problems are solved. It can be concluded, due to work carried out at DLR, that carbon dioxide poisoning of electrodes from rolled DLR electrodes does not take place. These investigations demonstrate that AFCs are highly efficient cells for portable and stationary applications.
A Two‐Phase Non‐Isothermal PEFC Model: Theory and Validation
Authors: Noponen M. , Birgersson E. , Ihonen J. , Vynnycky M. , Lundblad A. , Lindbergh G. 
Published: December 2004

AbstractA two‐dimensional, non‐isothermal, two‐phase model of a polymer electrolyte fuel cell (PEFC) is presented. The model is developed for conditions where variations in the streamwise direction are negligible. In addition, experiments were conducted with a segmented cell comprised of net flow fields. The, experimentally obtained, current distributions were used to validate the PEFC model developed. The PEFC model includes species transport and the phase change of water, coupled with conservation of momentum and mass, in the porous backing of the cathode, and conservation of charge and heat throughout the fuel cell. The current density in the active layer at the cathode is modelled with an agglomerate model, and the contact resistance for heat transfer over the material boundaries is taken into account. Good agreement was obtained between the modelled and experimental polarization curves. A temperature difference of 6 °C between the bipolar plate and active layer on the cathode, and a liquid saturation of 6% at the active layer in the cathode were observed at 1 A cm–2.
Direct Formic Acid Fuel Cells with 600 mA cm–2 at 0.4 V and 22 °C
Authors: Ha S. , Larsen R. , Zhu Y. , Masel R. I. 
Published: December 2004

AbstractA demonstration of direct formic acid fuel cells (DFAFCs) generating very high power density at ambient temperature is reported. In particular, the performance of the Pd black as an anode catalyst for DFAFCs with different formic acid feed concentrations at different operating temperatures has been evaluated. The Pd black based DFAFCs with dry air and zero backpressure can generate a maximum power density of 248 and 271 mW cm–2 at 22 °C and 30 °C respectively. The open cell potential is 0.90 V. These results show that DFAFCs are potentially excellent alternative power sources for small portable electronic devices.
PEFC Stack Operating in Anodic Dead End Mode
Authors: Dumercy L. , Péra M.‐C. , Glises R. , Hissel D. , Hamandi S. , Badin F. , Kauffmann J.‐M. 
Published: December 2004

AbstractThe polymer electrolyte fuel cell (PEFC) system is considered as an alternative power source and is particularly promising for mobile applications. This paper reports some experimental results performed on a PEFC stack, operating in anodic dead end mode. The flush frequency of the anode is investigated. In order to reduce hydrogen consumption in an embedded application, the flush frequency could be calculated from system modelling, according to the operating conditions. The first step of such a model is presented. It simulates the water exchanges between the anode and cathode channels in the anode dead end case. It has been implemented in a MATLAB® environment.
Organization and delivery of primary health care services in Petrópolis, Brazil
Authors: Macinko James , Almeida Celia , Oliveira Eliane dos Santos , Klingelhoefer de Sá Paulo 
Published: December 2004

AbstractThe objective of the study was to adapt and apply an instrument to measure the organizational features of the primary care system in the municipality of Petrópolis. The study compared the performance of the new Family Health Program (Programa Saúde da Família or PSF) with traditional primary care facilities using data from facility surveys and key informant interviews. The main results include: (a) the methodology was capable of distinguishing between the two types of primary care services in the municipality; (b) the PSF clinics scored higher on most dimensions of primary care, although in some areas the traditional health units had equivalent scores; and (c) data obtained from interviewing key informants was generally compatible with that obtained by conducting facility surveys. The results suggests that in spite of making important advances in primary care, the municipality of Petrópolis continues to face several challenges including the need to improve access, enforce the gatekeeper role of primary care, and improve the coordination and community orientation of both types of primary care services. The methodology could be used to set objectives and monitor progress towards improving the organization and delivery of primary care in Petrópolis and elsewhere. Copyright © 2004 John Wiley & Sons, Ltd.
A realistic approach to the evaluation of the quality management movement in health care systems: a comparison between European and African contexts based on Mintzberg's organizational models
Authors: Blaise P. , Kegels G. 
Published: December 2004

AbstractThe quality movement is gaining momentum worldwide in the field of health care. Initiated in industrialized countries, it steadily grows in Africa. However, there is no evidence that approaches designed to address issues in a given organizational context have the same effect in another one where issues present differently.Along the epistemological paradigm of realistic evaluation proposed by Pawson and Tilley, we use Mintzberg's organizational models to compare the configurations of European and African health care organizations and the trends followed by the quality management movement in both contexts. We illustrate how European health systems traditionally emphasize professional autonomy while African health systems are structured as command and control hierarchical systems. We illustrate how the quality movement in Europe emphasizes standardization of procedures, a characteristic of a mechanistic organization, while excessive standardization is part of the quality problem in Africa.We suggest that instilling professionalism may be a way forward for the quality movement in Africa to improve patient focus and responsiveness of responsible professionals. We also suggest that our interpretation of broad trends and contrasts may be used as a useful departure point to study the wide contextual diversity of the African experience with quality management. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of the radiopacifier in an acrylic bone cement on its mechanical, thermal, and physical properties: Barium sulfate‐containing cement versus iodine‐containing cement
Authors: Lewis Gladius , van Hooy‐Corstjens Catharina S.J. , Bhattaram Anuradha , Koole Leo H. 
Published: December 2004

AbstractIn all acrylic bone cement formulations in clinical use today, radiopacity is provided by micron‐sized particles (typical mean diameter of between about 1 and 2 μm) of either BaSO4 or ZrO2. However, a number of research reports have highlighted the fact that these particles have deleterious effects on various properties of the cured cement. Thus, there is interest in alternative radiopacifiers. The present study focuses on one such alternative. Specifically, a cement that contains covalently bound iodine in the powder (herein designated the I‐cement) was compared with a commercially available cement of comparable composition (C‐ment®3), in which radiopacity is provided by BaSO4 particles (this cement is herein designated the B‐cement), on the basis of the strength (σb), modulus (Eb), and work‐to‐fracture (Ub), under four‐point bending, plane‐strain fracture toughness (KIC), Weibull mean fatigue life, NWM (fatigue conditions: ±15 MPa; 2 Hz), activation energy (Q), and frequency factor (ln Z) for the cement polymerization process (both determined by using differential scanning calorimetry at heating rates of 5, 10, 15, and 20 K min−1), and the diffusion coefficient for the absorption of phosphate‐buffered saline at 37°C (D). For the B‐cement, the values of σb, Eb, Ub, KIC, NWM, Q, ln Z, and D were 53 ± 3 MPa, 3000 ± 120 MPa, 108 ± 15 kJ m−3, 1.67 ± 0.02 MPa✓m, 7197 cycles, 243 ± 17 kJ mol−1, 87 ± 6, and (3.15 ± 0.94) × 10−12 m2 s−1, respectively. For the I‐cement, the corresponding values were 58 ± 5 MPa, 2790 ± 140 MPa, 118 ± 45 kJ m−3, 1.73 ± 0.11 MPa✓m, 5520 cycles, 267 ± 19 kJ mol−1, 95 ± 9, and (3.83 ± 0.25) × 10−12 m2 s−1. For each of the properties of the fully cured cement, except for the rate constant of the polymerization reaction, at 37°C (k′), as estimated from the Q and ln Z results, there is no statistically significant difference between the two cements. k′ for the I‐cement was about a third that for the B‐cement, suggesting that the former cement has a higher thermal stability. The influence of various characteristics of the starting powder (mean particle size, particle size distribution, and morphology) on the properties of the cured cements appears to be complex. When all the present results are considered, there is a clear indication that the I‐cement is a viable candidate cement for use in cemented arthroplasties in place of the B‐cement. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 73B: 77–87, 2005
Sheath liquid interface for the coupling of normal‐phase liquid chromatography with electrospray mass spectrometry and its application to the analysis of neoflavonoids
Authors: Charles Laurence , Laure Frédéric , Raharivelomanana Phila , Bianchini Jean‐Pierre 
Published: December 2004

AbstractA novel interface that allows normal‐phase liquid chromatography to be coupled with electrospray ionization (ESI) is reported. A make‐up solution of 60 mM ammonium acetate in methanol, infused at a 5 µl min−1 flow‐rate at the tip of the electrospray probe, provides a sheath liquid which is poorly miscible with the chromatographic effluent, but promotes efficient ionization of the targeted analytes. Protonated molecules generated in the ESI source were subjected to tandem mass spectrometric experiments in a triple‐quadrupole mass spectrometer. The main fragmentation reactions were characterized for each analyte and specific mass spectral transitions were used to acquire chromatographic data in the multiple reaction monitoring detection mode. Results obtained during optimization of the sheath liquid composition and flow‐rate suggest that the electrospray process was mainly under the control of the make‐up solution, and that it forms an external charged layer around a neutral chromatographic mobile phase core. This sheath liquid interface was implemented for the analysis of some neoflavonoid compounds and its performance was evaluated. Limits of detection were established for calophillolide, inophyllum B, inophyllum P and inophyllum C at 100, 25, 15 and 100 ng ml−1, respectively. Copyright © 2004 John Wiley & Sons, Ltd.