bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correcting for compensating mechanisms related to productivity costs in economic evaluations of health care programmes
Authors: Jacob‐Tacken Karin H. M. , Koopmanschap Marc A. , Meerding Willem Jan , Severens Johan L. 
Published: October 2004

AbstractIn the economic evaluation of health care programmes, productivity costs are often estimated using patients' wages for the period of absence. However, the use of such methods for short periods of absence is controversial. A previous study found that short‐term absence is often compensated for during normal working hours and therefore does not lead to productivity losses. As such, the application of any approach almost certainly overestimates productivity costs. In this study, we examined the productivity costs for five different patient populations and one employee population, using the classical method and by identifying when extra effort was needed. In general, the results showed that productivity costs based on identifying extra effort were 25–30% of the classical estimates. For absences of just one day, productivity costs were relevant in only 17–19% of cases. For absences of two weeks or longer, productivity costs were relevant in 35–39% of cases. Measurement of the compensating mechanisms seemed to be valid, since there is considerable agreement between the opinion of supervisors and their employees about whether compensation covers productivity costs. There was much less agreement between supervisors and their employees on specific compensating mechanisms, however. The measurement of compensating mechanisms also seemed to be valid, because – as expected – different compensating mechanisms were reported for different occupations. In our study populations, compensating mechanisms appeared to differ with occupational characteristics, like part‐time work, managerial work and shift work. Copyright © 2004 John Wiley & Sons, Ltd.
Technology and managed care: patient benefits of telemedicine in a rural health care network
Authors: Berman Matthew , Fenaughty Andrea 
Published: October 2004

AbstractRural health providers have looked to telemedicine as a technology to reduce costs. However, virtual access to physicians and specialists may alter patients' demand for face‐to‐face physician access. We develop a model of service demand under managed care, and apply the model to a telemedicine application in rural Alaska. Provider‐imposed delays and patient costs were highly significant predictors of patient contingent choices in a survey of ENT clinic patients. The results suggest that telemedicine increased estimated patient benefits by about $40 per visit, and reduced patients' loss from rationing of access to physicians by about 20%. Copyright © 2004 John Wiley & Sons, Ltd.
Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation
Authors: Büscher R. , Täger G. , Dudzinski W. , Gleising B. , Wimmer M.A. , Fischer A. 
Published: October 2004

AbstractTo control and minimize wear of metal‐on‐metal hip joints it is essential to understand the mechanisms of debris generation.In vivo, mainly nanosize globular and needle‐shaped particles are found. These can neither stem from the action of abrasion nor from tribochemical reactions. In this study the acting wear mechanisms have been first identified on the surface by means of scanning electron microscopy (SEM). Afterwards, the microstructures of the subsurface regions of explants have been investigated using a transmission electron microscope (TEM). Observation of the subsurface gave additional insight about the microstructural changes of cobalt‐base alloys subjected to wear. At some distance from the surface, a network of stacking faults and hexagonal ϵ‐martensite was found strengthening the bulk material. This microstructure changed into a nanocrystalline type moving closer towards the surface. A comparison ofin vivodebris size and grain size of the surface suggests that the globular wear particles result from torn off nanocrystals, while the needle shaped particles are generated by fractured ϵ‐martensite. Identified cracks, propagating through the nanocrystalline layer, further support these findings. Thus, it is suggested that the dominating mechanism of particle generation for metal‐on‐metal joints is surface fatigue within a nanocrystalline surface layer. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 206–214, 2005
Pulpal temperature rise during light‐activated bleaching
Authors: Eldeniz Ayçe Unverdi , Usumez Aslihan , Usumez Serdar , Ozturk Nilgun 
Published: October 2004

AbstractThe purpose of this study was to measure intrapulpal temperature rise induced by two kinds of bleaching gels when the tooth was exposed to a variety of light‐curing units and a diode laser in vitro. The root portions of 80 extracted intact human maxillary central incisors were sectioned with a carborundum disk approximately 2 mm below the cementoenamel junction perpendicular to the long axis of the teeth. Two bleaching agents containing heat‐enhancing colorant was applied to the labial surface. Light‐curing units used were a conventional halogen (40 s), a high‐intensity halogen (30 s), a light‐emitting diode unit (40 s), and a diode laser (15 s). The temperature rise was measured in the pulpal chamber with a J‐type thermocouple wire that was connected to a data logger. Ten specimens were used for each system and bleaching‐agent combination. Differences between the starting temperature and highest temperature reading were taken and the calculated temperature changes were averaged to determine the mean value in temperature rise. Temperature rise values were compared using two‐way analysis of variance (ANOVA) at a preset α of 0.05. Temperature rise varied significantly depending on curing unit and diode laser used. The diode laser induced significantly higher temperature increases than any other curing unit (11.7°C). The light‐emitting diode unit produced the lowest temperature changes (6.0°C); however, there were no statistically significant differences among the curing units and there were no statistically significant differences between bleaching agents. Light activation of bleaching materials with diode laser caused higher temperature changes as compared to other curing units and the temperature rise detected was viewed as critical for pulpal health. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 254–259, 2005
Biological Natural Retting for Determining the Hierarchical Structuration of Banana Fibers
Authors: Gañán Piedad , Zuluaga Robin , Velez Juan Manuel , Mondragon Iñaki 
Published: October 2004

AbstractSummary: Extraction processes of natural fibers can be performed by different procedures that include mechanical, chemical and biological methods. Each method presents different advantages or drawbacks according to the amount of fiber produced or the quality and properties of fiber bundles obtained. In this study, biological natural retting was satisfactorily used for obtaining banana fibers from plant bunches. However, the most important contribution of this work refers to the description of the hierarchical microstructural ordering present in banana fiber bundles in both bundle surface and inner region. The chemical composition of banana fiber bundles has been evaluated by FTIR spectroscopy. Through exposure time, the fiber bundle configuration presents small variations in composition. The main changes are related to hemicellulose and pectins as they conform the outer walls of the bundle. Hierarchical helicoidal ordering in the bundle surface as well as orientation on the longitudinal axis of the bundle were observed by optical microscopy (OM) and scanning electron microscopy (SEM) for 3–4 μm surface fibers and 10–15 μm inner elementary fibers, respectively. With increasing exposure time, fiber bundle walls lose integrity, as reflected in their mechanical behavior.
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Gluconic Acid Production in Bioreactor with Immobilized Glucose Oxidase Plus Catalase on Polymer Membrane Adjacent to Anion‐Exchange Membrane
Authors: Godjevargova Tzonka , Dayal Rajeshwar , Turmanova Sevdalina 
Published: October 2004

AbstractSummary: Gluconic acid was obtained in the permeate side of the bioreactor with glucose oxidase (GOD) immobilized onto anion‐exchange membrane (AEM) of low‐density polyethylene grafted with 4‐vinylpiridine. The electric resistance of the anion‐exchange membranes was increased after the enzyme immobilization on the membrane. The gluconic acid productions were relatively low with the GOD immobilized by any method on the AEM. To increase the enzyme reaction efficiency, GOD was immobilized on membrane of AN copolymer (PAN) adjacent to an anion‐exchange membrane in bioreactor. Uses of anion‐exchange membrane led to selective removal of the gluconic acid from the glucose solution and reduce the gluconic acid inhibition. The amount of gluconic acid obtained in the permeate side of the bioreactor with the GOD immobilized on the PAN membrane adjacent to the AEM under electrodialysis was about 30 times higher than that obtained with enzyme directly bound to the AEM. The optimal substrate concentration in the feed side was found to be about 1 g/l. Further experiments were carried out with the co‐immobilized GOD plus Catalase (CAT) on the PAN membrane adjacent to the AEM to improve the efficiency of the immobilize system. The yield of this process was at least 95%. The storage stability of the co‐immobilized GOD and CAT was studied (lost 20% of initial activity for 90 d). The results obtained clearly showed the higher potential of the dual membrane bioreactor with GOD plus CAT bound to ultrafiltration polymer membrane adjacent to the AEM.Storage stability of GOD activity in GOD plus CAT immobilized on PAN//AEM membranes [♦] and on AEM [▴].magnified imageStorage stability of GOD activity in GOD plus CAT immobilized on PAN//AEM membranes [♦] and on AEM [▴].
Synthesis and Endosomolytic Properties of Poly(amidoamine) Block Copolymers
Authors: Lavignac Nathalie , Lazenby Michelle , Foka Peli , Malgesini Beatrice , Verpilio Ilario , Ferruti Paolo , Duncan Ruth 
Published: October 2004

AbstractSummary: The poly(amidoamine)s (PAAs) ISA 1 and ISA 23 display pH‐dependent conformational change and pH‐dependent membrane perturbation. These properties confer potential for use as endosomolytic polymers for intracytoplasmic delivery of toxins and genes. Both polymers are relatively non‐toxic, and moreover ISA 23 has the beneficial property in vivo, of being non hepatotropic when administered intravenously. Although ISA 23 and ISA 1 demonstrate ability to transfect cells, ISA 1 is also able to promote intracellular delivery of non‐permeant toxins. The aim of this study was to synthesise random and block copolymers of ISA 1 and ISA 23 and investigate whether these second generation hybrids would allow optimisation of PAA biological characteristics. Random and block copolymers of ISA 1 and ISA 23 were synthesised by hydrogen transfer polyaddition to generate a library of PAAs with an ISA 23:ISA 1 molar ratios of 2:1 to 4:1. The resultant polymers have a pI slightly below 7.4 and a $\overline M _{\rm w}$ of 19 900–49 000 g/mol and a $\overline M _{\rm n}$ of 13 100–24 100 g/mol. Whereas none of the random or block copolymers were haemolytic at pH 7.4 all demonstrated pH‐dependent membrane activity. At pH 5.5 they caused 50–60% haemoglobin (Hb) release over 1 h. This was slightly less than that seen for ISA 23 (80% Hb release). None of the copolymers were cytotoxic against B16F10 cells during a 72 h incubation (IC50 > 2 mg/ml; MTT assay). The ability of the random and block copolymer PAAs to deliver the toxin gelonin was also examined, but only ISA 1 and the block copolymer B2 (ISA 23:ISA 1 at a 2:1 molar ratio) were able to promote intracellular delivery, as measured by cytotoxic activity. It would be interesting to study the body distribution of B2 and determine whether this toxin‐delivering PAA is able to escape liver capture.
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Opal Gels Templated Synthesis of Structured Titania Materials
Authors: Rong Jianhua , Ma Jin , Yang Zhenzhong 
Published: October 2004

AbstractSummary: Core/shell opal gels of sulfonated polystyrene were used as templates to synthesize structured crystalline titania materials. Under acidic conditions, opal materials with hollow spheres of controllable shell thickness and cavity size were prepared. Under neutral conditions, inverse opal inorganic materials with a tunable pore size were prepared. It is crucial that proton ions induce a preferential sol/gel process, forming titania in the gel.Scanning electron micrograph of the interior region of a structured titania material derived from the G1 template used here. The inset shows broken spheres in which the internal cavity can be observed.imageScanning electron micrograph of the interior region of a structured titania material derived from the G1 template used here. The inset shows broken spheres in which the internal cavity can be observed.
Silk Sericin Retards the Crystallization of Silk Fibroin
Authors: Lee Ki Hoon 
Published: October 2004

AbstractSummary: The thermal and structural analysis of silk fibroin (SF) and silk sericin (SS) blend films reveals that the crystallization of SF is retarded in the presence of SS. Although a phase separation was observed, there might be a strong interaction at the boundary of the SF and SS through intermolecular hydrogen bonding, which restricts the conformational transition of SF.TEM image of the cross‐section of the SF/SS blend (75:25) film (magnification: ×15 000).imageTEM image of the cross‐section of the SF/SS blend (75:25) film (magnification: ×15 000).
Mass spectrometry in aging research
Authors: Schöneich Christian 
Published: October 2004

AbstractThis review covers the application of mass spectrometric techniques to aging research. Modern proteomic strategies will be discussed as well as the targeted analysis of specific proteins for the correlation of post‐translational modifications with protein function. Selected examples will show both the power and also current limitations of the respective techniques. Experimental results and strategies are discussed in view of current theories of the aging process. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:701–718, 2005
Das β‐adrenerge System: Pharmakologische Aspekte
Authors: Hein Lutz 
Published: October 2004

AbstractDas adrenerge System steuert eine Vielzahl von wichtigen physiologischen Funktionen im zentralen und im peripheren, sympathischen Nervensystem. Die beiden endoge‐nen Effektoren Noradrenalin und Adrenalin sind die Liganden für die Familie der adrenergen Rezeptoren mit insgesamt neun Mitgliedern. Dazu zählen drei Rezeptorsubtypen der α1‐Gruppe, drei α2‐Rezeptoren sowie die drei β‐Rezeptoren.
Die räumliche Betrachtung und Beschreibung von Nebivolol: Stereochemie der Beta‐Blocker
Authors: Siebert Carsten D. 
Published: October 2004

AbstractNebivolol ist ein in vieler Hinsicht interessantes Molekül. Sowohl der synergistische pharmakologische Effekt seiner beiden Enantiomere als auch die stereochemische Analyse zeigen sehr schön den Konnex zwischen Chemie und Pharmazie. Die im Lehrbetrieb sehr oft getrennt vermittelten Kenntnisse über die Synthese organisch‐chemischer Verbindungen, Analytik von Wirkstoffen, Stereochemie, Molekularpharmakologie und medizinischem Nutzen in der Pharmakotherapie kristallisieren sich beispielhaft an dem β1‐Adrenozeptor‐Antagonisten Nebivolol. Dabei stellt Nebivolol keineswegs einen besonderen Fall dar, analoge stereochemische Betrachtungen lassen sich z.B. auch an dem Muskelrelaxans Mivacuriumchlorid [1] anstellen.In den letzten Jahren konnte an vielen Arzneistoffen anhand der dreidimensionalen Stuktur gezeigt werden, dass Enantiomeren oder Diastereomeren häufig eine unterschiedliche pharmakodynamische und pharmakokinetische Wirkung zukommt. Dies hat dazu geführt, dass der Anteil neu zugelassener Stereoisomeren‐reiner Pharmaka in den letzten fünf Jahren bei 60 % lag [5]. Dies zeigt deutlich, dass die exakte räumliche Beschreibung eines chemischen Moleküls zum grundlegenden Verständnis von Wirkaktivität gehört. In diesem Sinne ist Nebivolol ein Paradebeispiel für eine stereochemische Übung.
Verbesserte Therapie durch optimierte Arzneiformen?: Schnelle Freisetzung oder Retardformulierung?
Authors: Warnke André , Blume Henning 
Published: October 2004

AbstractAls im Jahr 1964 Propranolol als erster β‐Rezeptorenblocker in die Therapie eingeführt wurde, war keineswegs vorauszusehen, dass dies den Ausgangspunkt für eine fulminante Entwicklung in der Arzneimittelforschung darstellen würde. Diese betraf in erster Linie die Synthese neuer Derivate mit grundsätzlich analoger Struktur, die alle über eine kompetitive Hemmung der durch β‐Rezeptoren vermittelten Effekte der Katecholamine prinzipiell ähnliche Wirkungen entfalten. Dennoch unterscheiden sich die einzelnen Substanzen mehr oder weniger stark in ihren pharmakodynamischen bzw. pharmakokinetischen Eigenschaften.
Die Pharmazeutische Betreuung von Patienten mit Hypertonie: Was ist beim Einsatz von Beta‐Adrenozeptorenblockern zu beachten?
Authors: Diers Karsten 
Published: October 2004

AbstractPatienten mit hohem Blutdruck, die häufig mit β‐Blockern behandelt werden, sind trotz guter medikamentöser Therapiemöglichkeiten in einer Vielzahl von Fällen inadäquat eingestellt und erreichen die geforderten Blutdruckzielwerte von 140/90 mm Hg nicht. Als Grund hierfür kann neben dem fehlenden Leidensdruck der Patienten, der eine Krankheits‐ und Therapieeinsicht nachhaltig erschwert, die Angst vor Neben‐ und Wechselwirkungen bzw. deren reales Auftreten festgehalten werden. Dabei haben neuere Studien zeigen können, dass kardioselektive β‐Blocker oder solche mit vasodilatierenden Zusatzeigenschaften die für unselektive Pharmaka üblichen unerwünschten Wirkungen in weitaus geringerem Maße zeigen und bei entsprechenden Kontrollen auch bei obstruktiven Atemwegserkrankungen und bei Diabetikern eingesetzt werden können. Häufige Peak‐Flow‐ bzw. Blutzuckermessungen sowie die Dokumentation der Gesamtmedikation kann im Rahmen einen sinnvollen Beitrag zum Abbau der genannten Ängste und zur Verbesserung der Therapietreue der Betreuung solcher Patienten leisten und helfen unerwünschte Ereignisse so gering wie möglich zu halten.
Vioxx® und die anderen Coxibe
Authors: Steinbilber Dieter , Laufer Stefan 
Published: October 2004

AbstractAm 30. September 2004 wurde der selektive Cyclooxygenase (COX)‐2‐Hemmer Rofecoxib (Vioxx®) vom Markt genommen. Das Präparat wurde in Deutschland von MSD vermarktet und erzielte weltweit einen jährlichen Umsatz von 2 Milliarden EURO.
Melt rheological behavior of starch‐based matrix composites reinforced with short sisal fibers
Authors: Alvarez V. A. , Terenzi A. , Kenny J. M. , Vázquez A. 
Published: October 2004

AbstractA systematic analysis of the melt rheological behavior of a commercial starch‐based (MaterBi®) matrix composite reinforced with short sisal fibers is presented. The effects of shear rate, temperature, fiber content and treatment were analyzed by parallel‐plate rheometry, and classical non‐Newtonian models were applied to analyze the pseudoplasticity behavior of the molten composite systems. It is reported that shear rate is the most influential processing condition, while, from the point of view of the material structure, the intercalation effectiveness of the matrix in the fibers is directly linked to the rheological behavior. In fact, processing techniques with high stresses and more efficient mechanical mixing promote the opening of fiber bundles, increasing the aspect ratio of the fibers and the average viscosity of the molten composite. A similar effect on the increase of the aspect ratio and composite viscosity is observed when treated fibers are used. Polym. Eng. Sci. 44:1907–1914, 2004. © 2004 Society of Plastics Engineers.
Measurement and prediction of diffusion coefficients of supercritical CO2in molten polymers
Authors: Areerat Surat , Funami Eita , Hayata Yusuke , Nakagawa Dai , Ohshima Masahiro 
Published: October 2004

AbstractThe solubility and diffusivity of supercritical carbon dioxide (sc‐CO2) in low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), polypropylene (PP), ethylene‐ethylacrylate copolymer (EEA) and polystyrene (PS) were measured at temperatures from 150°C to 200°C and pressures up to 12 MPa by using the Magnetic Suspension Balance (MSB), a gravimetric technique for gas sorption measurements. The solubility of CO2in each polymer was expressed by Henry's constant. The interaction parameter between CO2and polymer could be obtained from the solubility data, and it was used to estimate the Pressure‐Volume‐Temperature relationship and the specific free volume of polymer/CO2mixtures. The diffusion coefficients were also measured by the MSB for each polymer. The resulting diffusion coefficients were correlated with the estimated free volume of polymer/CO2mixture. Combining Fujita's and Maeda and Paul's diffusion models, a model was newly developed in order to predict diffusion coefficients for the polymers studied. Polym. Eng. Sci. 44:1915–1924, 2004. © 2004 Society of Plastics Engineers.
A temperature‐dependent adaptive controller. Part II: Design and implementation
Authors: Dubay Rickey , Lakhram Rodney 
Published: October 2004

AbstractA generic online temperature‐dependent adaptive control procedure to redefine the controller parameters was developed from dynamic models to achieve good tracking of injection‐velocity setpoint profiles during filling of a mold cavity. This adaptive control procedure (ACP) incorporates algorithms for process open‐loop testing and modeling, control simulations, and online controller updating. These functionalities are embedded into a main program that provides overall control of mold‐filling velocity. The controller's dynamic matrix is updated as changes in the setpoint melt temperature occur. It was shown that the ACP can provide an effective and systematic approach for controlling injection mold‐filling velocity for any plastic material over its operating melt temperature range. Polym. Eng. Sci. 44:1934–1940, 2004. © 2004 Society of Plastics Engineers.
Rheology and processing of BaSO4‐filled medical‐grade thermoplastic polyurethane
Authors: Lu Guangyu , Kalyon Dilhan M. , Yilgör Iskender , Yilgör Emel 
Published: October 2004

AbstractThe rheological and processing behavior of BaSO4‐fllled medical‐grade (additive‐free) thermoplastic polyurethanes (TPUs) was investigated. The rheology and the single‐screw and twin‐screw extrusion processing of filled TPU were found to be complicated by the moisture and the air entrained into the suspension upon the incorporation of the filler BaSO4. It was observed that the 20 vol% BaSO4‐filled TPU exhibits decreased, rather than increased, shear viscosity and elasticity (as manifested through smaller storage modulus values in small‐amplitude oscillatory shear flow) in comparison to unfilled TPU in the temperature range of 190°C to 200°C at which these materials are usually processed. The moisture remaining in the BaSO4 will hydrolyze the polymer, leading to a decrease in the molecular weight of the TPU. However, the moisture contained in the filler itself is not sufficient to explain the significant reductions in viscosity and elasticity of the suspension upon the compounding of the BaSO4. It is shown that the major factor giving rise to the reductions in elasticity and the viscosity of the suspension of TPU and BaSO4 is the air (and the moisture air contains) entrained into the extruder during the feeding of the BaSO4. Air, carried with the filler into the extruder, is entrained into the suspension to hydrolyze the TPU and to further impart a foamy structure under typical processing conditions to significantly reduce the shear viscosity and the elasticity of the suspension in comparison to unfilled TPU. Polym. Eng. Sci. 44:1941–1948, 2004. © 2004 Society of Plastics Engineers.