bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composite implantation of mesenchymal stem cells with endothelial progenitor cells enhances tissue‐engineered bone formation
Authors: Usami Kazutada , Mizuno Hirokazu , Okada Kunihiko , Narita Yuji , Aoki Mika , Kondo Takahisa , Mizuno Daiki , Mase Junji , Nishiguchi Hiroaki , Kagami Hideaki , Ueda Minoru 
Published: June 2008

AbstractFor successful tissue engineering, neovascularization of the implanted tissue is critical. Factors generated by endothelial cells are also considered crucial for the process of osteogenesis. The direct effects of supplementing tissue engineered constructs with cultured endothelial progenitor cells (EPCs) for enhancing bone regeneration have not been reported. In this study, we investigated the potential of EPCs to facilitate neovascularization in implants and evaluated their influence on bone regeneration. The influence of EPC soluble factors on osteogenic differentiation of mesenchymal stem cells (MSCs) was tested by adding EPC culture supernatant to MSC culture medium. To evaluate the influence of EPCs on MSC osteogenesis, canine MSCs‐derived osteogenic cells and EPCs were seeded independently onto collagen fiber mesh scaffolds and co‐transplanted to nude mice subcutaneously. Results from coimplant experiments were compared to implanted cells absent of EPCs 12 weeks after implantation. Factors from the culture supernatant of EPCs did not influence MSC differentiation. Coimplanted EPCs increased neovascularization and the capillary score was 1.6‐fold higher as compared to the MSC only group (p < 0.05). Bone area was also greater in the MSC + EPC group (p < 0.05) and the bone thickness was 1.3‐fold greater in the MSC + EPC group than the MSC only group (p < 0.05). These results suggest that soluble factors generated by EPCs may not facilitate the osteogenic differentiation of MSCs; however, newly formed vasculature may enhance regeneration of tissue‐engineered bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Acute paraplegia in a patient with AIDS and a normal CSF examination
Authors: Lunn M. P. T. , Clarke C. , Aldeen T. 
Published: June 2008

AbstractWe report a case of tuberculous myeloradiculitis in a patient with AIDS. The case highlights the difficulty in reaching a diagnosis for the neurological symptoms of a patient with a normal CSF examination and the need for HIV screening of immune‐compromised patients with myeloradiculitis. Journal of Hospital Medicine 2008;3:279–280. © 2008 Society of Hospital Medicine.
Sleepiness in critical care nurses: Results of a pilot study
Authors: Surani Salim , Subramanian Shyam , Babbar Harsh , Murphy Jane , Aguillar Raymond 
Published: June 2008

AbstractBACKGROUND:Sleep deprivation, compounded by circadian disruptions, is a common problem in health care workers. Sleepiness in nurses has important implications for patients as well as nurses' own safety.OBJECTIVE:The objective of the study was to assess comprehensively sleepiness levels in post‐night‐shift nurses.METHODS:Post‐night‐shift nurses in the ICU and on general floors (medicine and surgery) were assessed using subjective (Epworth Sleepiness Scale [ESS]) and objective (Mean Sleep Latency Test [MSLT]) measures.RESULTS:ESS was abnormal (>8) in 7 of 10 ICU nurses compared with 2 of 10 floor nurses (P < .005), and mean ESS score was also higher (8.7 ± 3.9 vs. 5.6 ± 2.1, respectively; P = 0.042). MSLT values for the first nap period were in the pathologic range in the ICU nurses compared with the floor nurses (4.65 ± 5.5 vs. 10.85 ± 7.4 minutes, respectively; P < .05).CONCLUSIONS:Post‐night‐shift RNs working in the ICU have a pathologic degree of sleepiness. Journal of Hospital Medicine 2008;3:200–205. © 2008 Society of Hospital Medicine.
Influence of physician specialty on outcomes after acute ischemic stroke
Authors: Gillum Leslie Allison , Johnston S. Claiborne 
Published: June 2008

AbstractBACKGROUND:Specialist care has been shown to improve outcomes for several complex medical conditions. For patients with ischemic stroke, prior studies have suggested that admission to the care of neurologists is associated with better outcomes, but these studies may have incompletely controlled for confounding prognostic differences.OBJECTIVE:The objective of this study was to evaluate whether admission to the care of a neurologist is associated with improvement in outcomes of stroke patients after controlling for initial prognostic differences.DESIGN:This was a retrospective cohort study.SETTING:Participating in the study were 113 U.S. academic hospitals.PATIENTS:Demographic and clinical data for all ischemic stroke patients admitted through emergency departments from 1997 to 1999 were collected from an administrative database.MEASUREMENTS:In traditional analyses, we evaluated attending physician specialty as a predictor of in‐hospital mortality. In grouped‐treatment (GT) analyses, a method based on the instrumental variable approach that bypasses selection bias, the hospital rate of stroke admission to neurologists was used as the predictor. We used generalized estimating equations for all analyses, adjusting for demographics, urgency, comorbid illness severity, and treatment volume.RESULTS:Of 26,925 ischemic stroke patients, 60% were admitted to the care of neurologists. In univariate analysis, risk of in‐hospital mortality in cases admitted to neurologists (4.6%) was lower than that for those admitted to generalists (9.5%; P < .001). Adjustment for individual‐level characteristics did not alter the association (0.60 OR, 95% CI, 0.50–0.72; P < .001). However, no advantage to neurologist admission was demonstrated in GT analysis, with mortality rates similar at hospitals admitting different proportions of ischemic stroke cases to neurologists (1.02 OR, 95% CI, 0.79–1.30; P = .90).CONCLUSIONS:Differences in ischemic stroke outcomes between neurologists and generalists may be a result of differences in initial prognosis because outcomes are no better at hospitals that admit patients to the care of neurologists more frequently. Journal of Hospital Medicine 2008;3:184–192. © 2008 Society of Hospital Medicine.
History of mass spectrometry at the Olympic Games
Authors: Hemmersbach Peter 
Published: June 2008

AbstractMass spectrometry has played a decisive role in doping analysis and doping control in human sport for almost 40 years. The standard of qualitative and quantitative determinations in body fluids has always attracted maximum attention from scientists. With its unique sensitivity and selectivity properties, mass spectrometry provides state‐of‐the‐art technology in analytical chemistry. Both anti‐doping organizations and the athletes concerned expect the utmost endeavours to prevent false‐positive and false‐negative results of the analytical evidence.The Olympic Games play an important role in international sport today and are milestones for technical development in doping analysis. This review of the part played by mass spectrometry in doping control from Munich 1972 to Beijing 2008 Olympics gives an overview of how doping analysis has developed and where we are today.In recognizing the achievements made towards effective doping control, it is of the utmost importance to applaud the joint endeavours of the World Anti‐Doping Agency, the International Olympic Committee, the international federations and national anti‐doping agencies to combat doping. Advances against the misuse of prohibited substances and methods, which are performance‐enhancing, dangerous to health and violate the spirit of sport, can be achieved only if all the stakeholders work together. Copyright © 2008 John Wiley & Sons, Ltd.
Physical Gelation of Amphiphilic Poly(N‐isopropylacrylamide): Influence of the Hydrophobic Groups
Authors: Wintgens Véronique , Amiel Catherine 
Published: June 2008

AbstractThe self‐assembling properties of hydrophobically modified (N‐isopropylacrylamide) have been investigated by dynamic light scattering and rheological measurements. Size of the globules and transmission of the solutions vary strongly in the same range of temperature. The presence of hydrophobic groups leads to contraction of the globules' size compared to poly(N‐isopropylacrylamide) (PNIPAM). The viscoelastic properties of the samples in aqueous solution have been investigated as a function of copolymer concentration, structure of the hydrophobic group (dodecyl or adamantyl group), substitution level (1–5%) and over a temperature range covering the lower critical solution temperature (LCST). At high concentration and high level of adamantyl substitution, gelation is observed several degrees before the phase transition. A physical network is formed due to the strong hydrophobic interactions, and this physical gel undergoes phase transition without macroscopic phase separation.magnified image
Contractive Polymeric Complex Micelles as Thermo‐Sensitive Nanopumps
Authors: Wang Huan , An Yingli , Huang Nan , Ma Rujiang , Li Junbo , Shi Linqi 
Published: June 2008

AbstractComplex micelles were obtained from PS‐b‐PNIPAM‐b‐PAA micelles and PEG‐b‐P4VP block copolymers via the strong electrostatic interaction and hydrogen bonding between PAA and P4VP blocks in water. The PS block formed the core and the PAA/P4VP complex shell functioned as a semi‐permeable membrane which could control the permeation of small molecules. Between the core and shell, the large fluid‐filled space that was formed with the thermoresponsive PNIPAM gel could retain the loaded drug for a long period of time. With increasing temperature, the shrinkage of the PNIPAM coils pumped the drug out of the complex micelles. The complex micelles functioned as a contractive “nanopump”, which could potentially be applied as a thermosensitive controlled release system.magnified image
A Methodology for Investigating Protein Adhesion and Adsorption to Microarrayed Combinatorial Polymers
Authors: Taylor Michael , Urquhart Andrew J. , Anderson Daniel G. , Williams Philip M. , Langer Robert , Alexander Morgan R. , Davies Martyn C. 
Published: June 2008

AbstractHere, we report the use of fluorescently labelled proteins to study protein adsorption to microarrayed synthetic polymers for the first time, indicating that this method is appropriate for the study of protein adsorption on these arrays. To investigate protein adhesion directly we use atomic force microscopy (AFM) to measure the force of adhesion between a protein‐coated probe and the arrayed polymers. Both approaches show promise as methods for screening protein interactions with polymers in a microarray format. Comparison of these very different measures of protein–surface interactions indicate a good correlation.magnified image
Supramolecular Nanoscaled Self‐Assembly of Bifunctional Cyclodextrin and Trifunctional Melamine Precursors
Authors: Choi Sung‐Ho , Jung Hyun‐Ho , Kim Jae‐Il , Furusho Horotoshi , Geckeler Kurt E 
Published: June 2008

AbstractA new type of guest–core supramolecular networks via inclusion complexation of nanoscaled building blocks such as bifunctional cyclodextrin (CD) derivatives and trifunctional melamine derivatives were prepared. By using AFM and an adoption of the cryo‐TEM technique under high acceleration voltage the nanoscale supramolecular network structure, nexus units, and CD molecules could be visualized. In addition to the 2‐D 1H NMR rotating frame Overhauser effect spectroscopy (ROESY) experiments, theoretical studies on the molecular docking of the CDs and the melamine derivative have been conducted to elucidate the thermodynamic properties by the two‐layered integrated molecular orbital and molecular mechanics (ONIOM) method, which combines both quantum mechanics and molecular mechanics (QM/MM) calculations.magnified image
Engineering of Covalently Immobilized Gradients of RGD Peptides on Hydrogel Scaffolds: Effect on Cell Behaviour
Authors: Guarnieri Daniela , Borzacchiello Assunta , De Capua Antonia , Ruvo Menotti , Netti Paolo A. 
Published: June 2008

AbstractSummary:The aim of this study has been to design a system for the preparation of Polyethylene‐glycol (PEG) based hydrogels with a controlled spatial distribution of covalently immobilised RGD adhesion signals in order to control and guide cell response for tissue engineering application. Gradients of immobilised RGD peptides were characterized by confocal microscopy analysis. Moreover, the effect of RGD spatial distribution on cell behaviour was evaluated by using mouse embryo fibroblasts NIH3T3. In particular, we observed cell adhesion and migration of fibroblasts seeded on RGD gradient compared to cells on control hydrogels having an uniform distribution of RGD. Our data suggest that a linear gradient of covalently immobilised adhesion signals affects cell behaviour. In particular, cells feel RGD gradient and oriented themselves and move along gradient direction.
Determination of Water and Solute Transport in Polyacrylamide Gels
Authors: Brahm Jesper , Lessel Robert , Ditlev Sisse , Schmidt Richard 
Published: June 2008

AbstractSummary:Water exchange between five polyacrylamide gels (Bulkamid®, Aquamid®, Rectamid®, HV‐PAAG, Acuvue) with a physiological salt solution was determined by means of tritium‐labeled water. Urea and chloride exchange was also determined in Acuvue. The method was a modified version to measure rapid transport processes in red blood cells. The study shows that water and solutes easily exchange between the hydrogel under study and the surrounding medium, independent of the solid polymer content (2.5–40 wt%) and an over ten‐fold variation of the cross‐linking density.
The invisible reality of arthritis: A qualitative analysis of an online message board
Authors: Hadert Aimee , Rodham Karen 
Published: June 2008

AbstractBackground and aim: Living with a chronic illness, such as arthritis, creates many psychosocial stressors, which can be difficult to cope with. Exploring the interactions which take place on an online message board for people with arthritis may provide insight into both the social support offered, as well as highlighting the groups' needs that perhaps are not being met in a more formal ‘offline’ setting. The aim of this study was to investigate how and why an arthritis online message board was used.Methods: A retrospective three‐month period of discussions posted on an online message board for people who have arthritis was downloaded into a word document. Collecting data in this manner ensured that completed discussions were captured. Eighty‐seven initial messages and 981 replies were analysed. The discussions were analysed using interpretive phenomenological analysis.Results: Four master themes were identified. Firstly, the invisible reality of the condition; secondly, information exchange, whereby users of the message board were shown to be both seeking and providing information; thirdly, while users praised the support they received from family and friends, the support offered and received online was considered to provide additional benefits. Finally, the message board allowed users to share (primarily negative) emotions which they felt unable to express in their offline worlds.Conclusion and implications: Patients do not always understand the information being offered by health care professionals, and they do not have the confidence to ask for clarification. Health care professionals need to ensure that they find a way of checking levels of patient understanding. Failure to do so means that patients may turn to alternative sources, which may not provide accurate information. The study also showed that people with arthritic conditions find it difficult to express how they are feeling in their offline world; furthermore, they find it difficult to ask for support from their significant others, preferring instead to ‘suffer in silence’ and seek support from the online community, potentially further isolating them from the support of those in their offline world. There is scope for such patients to be both empowered and educated, so that they are better able to ask for the help they need, which in turn will help to counteract the danger of isolation. Copyright © 2008 John Wiley & Sons, Ltd.
Step size adjustment and extrapolation for time‐stepping schemes in non‐smooth dynamics
Authors: Studer C. , Leine R. I. , Glocker Ch. 
Published: June 2008

AbstractIn this paper we use step size adjustment and extrapolation methods to improve Moreau's time‐stepping scheme for the numerical integration of non‐smooth mechanical systems, i.e. systems with impact and friction. The scheme yields a system of inclusions, which is transformed into a system of projective equations. These equations are solved iteratively. Switching points are time instants for which the structure of the mechanical system changes, for example, time instants for which a sticking friction element begins to slide. We show how switching points can be localized and how these points can be resolved by choosing a minimal step size. In order to improve the integration of non‐smooth systems in the smooth parts, we show how the time‐stepping method can be used as a base integration scheme for extrapolation methods, which allow for an increase in the integration order. Switching points are processed by a small time step, while time intervals during which the structure of the system does not change are computed with a larger step size and improved integration order. The overall algorithm, which consists of a time‐stepping module, an extrapolation module and a step size adjustment module, is discussed in detail and some examples are given. Copyright © 2008 John Wiley & Sons, Ltd.
Experimental characterization and morphology investigation of composites based on high‐density and low‐density polyethylene reinforced with non‐crimp‐stitched glass fabrics
Authors: Sarıkanat Mehmet , Çeçen Volkan , Erden Seçkin , Baltacı Aysun 
Published: June 2008

AbstractIn this study, the effects of matrix material on mechanical properties were investigated in glass fiber reinforced high‐density and low‐density polyethylene composites. Also, in order to compare the fiber configuration effect on anisotropic behavior, unidirectional and biaxial glass fabrics were used as reinforcement material. Composite laminates were manufactured via the compression molding technique. Tensile and three‐point bending flexural tests were conducted up to failure on specimens cut out in different directions. Extensive fracture photomicrographs were presented for observing the failure modes (e.g. delamination) of the composites resulting from a variety of loading conditions. In addition, Scanning electron micrographs of postfractured surfaces of composites were interpreted in an attempt to explain the failure mechanisms (adhesive or cohesive failure) of the composites. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Preparation and mechanical properties of waterborne polyurethane/carbon nanotube composites
Authors: Zhao Cai‐Xia , Zhang Wei‐De , Sun Dong‐Cheng 
Published: June 2008

AbstractWaterborne polyurethane (WBPU) and multiwalled carbon nanotubes (CNTs) composite films with 0–4.0 wt% CNTs were prepared by ultrasonic dispersion of carboxylic acid‐functionalized CNTs in WBPU followed by emulsion casting process. The elongations at break of the WBPU/CNTs composites increase with the incorporation of CNTs. The tensile strength and crystallinity of the nanocomposite films with lower CNTs contents (<2 wt%) increase obviously; while the tensile strengths of the composites with more CNTs (≥2 wt%) decrease, in contrast to the pure PU film. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that the CNTs are uniformly dispersed in the composites incorporated with lower CNTs contents (≤1.5 wt%). However, aggregation of CNTs increased with increasing CNTs content in the WBPU/CNTs composites, causing the macrophase separation. The dispersion state of the CNTs affects the crystallinity of the PU matrix and the phase separation of the composites, which are two key factors to influence the mechanical properties of the WBPU/CNTs composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Deterioration in mechanical properties of glass fiber‐reinforced nylon 6,6 composites by aqueous calcium chloride mixture solutions
Authors: Dhevi D. Manjula , Choi Chang Woo , Prabu A. Anand , Kim Kap Jin 
Published: June 2008

AbstractIn this article, nylon 6,6 (NY66) and glass fiber‐(30 wt%) reinforced NY66 (GFNY66) specimens were immersed in various aqueous calcium chloride (aq. CaCl2) mixture solutions at different thermal conditions for varying intervals of time, and analyzed using attenuated total reflection‐infrared (ATR‐IR) spectroscopy, inductively coupled plasma (ICP), energy dispersive X‐ray (EDX), gel permeation chromatography (GPC), and mechanical studies. ICP data revealed increasing concentration of absorbed Ca2+ ions with increasing immersion time resulting in disruption of intra‐ and intermolecular H‐bonding as confirmed using ATR‐IR results. From EDX data, the ratio of Ca2+ and Cl− ions absorbed by NY66 was calculated and found to follow its stoichiometric equivalence. GPC data exhibited less reduction in Mn and Mw for aq. CaCl2‐treated NY66 specimens suggesting the absence of any significant chemical degradation, but the occurrence of only physical changes involving H‐bond breakage and the formation of new CO···Ca2+ dative bond in NY66 matrix. The mechanical properties of GFNY66 samples treated with various types of aq. CaCl2 solutions exhibited pronounced deterioration, possibly due to the interfacial failure between glass fiber and NY66 matrix. The results obtained from this study were quite useful toward understanding the degradation mechanism in NY66 and GFNY66 caused by various aq. CaCl2 mixture solutions, and will be helpful in improving the mechanical properties of recycled NY66. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Toughness and reinforcement of diglycidyl ether of bisphenol‐A by hyperbranched poly(trimellitic anhydride‐butanediol glycol) ester epoxy resin
Authors: Zhang Daohong , Chen Yukun , Jia Demin 
Published: June 2008

AbstractHyperbranched epoxy resin shows best comprehensive performance in epoxy resin system and is considered as a kind of toughness and reinforcement additive. This article reports on the use of novel hyperbranched poly(trimellitic anhydride‐butanediol glycol) ester epoxy resin (HTBE) prepared by us as a functional additive to an epoxy amine resin system. The effect of molecular weight and content of the HTBE on the performance of the diglycidyl ether of bisphenol‐A (DGEBA)/HTBE hybrid resin are discussed in detail, and their performance has maximum with the increase of content and molecular weight of HTBE. The impact strength and fracture toughness of the hybrid resin containing 9 wt% second generation of HTBE are 48.2 kJ/m2 and 2.71 MPa m1/2, and which almost are 2.77 and 1.5 times of DGEBA performance respectively. Furthermore, the tensile and flexural strength can also be enhanced about 17%. The fracture surface micrograph of hybrid resin shows no microphase separation of the HTBE/DGEBA blends that facilitates an enhanced interaction to achieve excellent toughness and strength enhancement of the cured systems by scanning electron microscope (SEM). A novel situ reinforcing and toughening mechanism and model are discovered and confirmed by SEM, molecular simulation, and dynamic mechanical thermal analysis technology. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers