bluuebunny/crossref_metadata_2025_split huggingface dataset:
NHS Direct: managing demand for primary care?
Authors: Mark Annabelle L. , Shepherd Ifan D. H. 
Published: March 2004

AbstractThis paper considers how NHS Direct is affecting demand for primary care in particular out‐of‐hours services from GPs. This is reviewed through a 3‐year study of NHS Direct and HARMONI, the integrated telephone health helpline based in West London. It describes the policy background and development of the services on the site, and some of the outcomes of the HARMONI commissioned research to answer the question ‘Has NHS Direct increased the workload for HARMONI doctors?’.The research adopted both a qualitative and quantitative approach using cross‐sectional and longitudinal analysis of the data collected. The analysis of the data reveals the issues as both complex and dynamic in nature. The research shows that while there has been no significant change to the total volume of activity, changes within patient groups notably the elderly and children, and in individual GP practices may be significant. In addition, the changes in organizational arrangements may influence significant changes in referral patterns such as GP out‐of‐hours visits. This was confirmed in the interview data indicating a link between the change in nurses' role from gatekeeper to patient advocate, which happened when they ceased to be employees of the part‐time co‐op and began to work instead for the 24 hours, 7 days a week NHS Direct service.The conclusions drawn are that behavioural and organizational changes are at least as significant as the evidence‐based computerized decision support software in changing the demand for primary care. Further evidence cited is that a different demand pattern of calls was experienced by those local GPs not integrated into out‐of‐hours provision at NHS Direct West London at the time of the study. Copyright © 2004 John Wiley & Sons, Ltd.
Costing of services of Vietnamese hospitals: identifying costs in one central, two provincial and two district hospitals using a standard methodology
Authors: Flessa Steffen , Dung Nghiem Tran 
Published: March 2004

AbstractBackgroundThe People's Republic of Vietnam is currently in a period of transition from a purely socialistic country towards a so‐called socialist market economy. Since the introduction of the Doi Moi policy in 1987, health care services have been liberalized, medical practitioners have received the right to open private hospitals and private pharmacies are booming. However, the majority of inhabitants strongly depends on governmental hospital services. These services are currently going through a financial crisis. This demands the quest for efficiency and the wise allocation of public funds.Research questionThe efficient allocation of funds depends on the quotient between costs and health outcomes, but the costs of health services in Vietnamese hospitals are unknown. Therefore the study analysed five hospitals in Vietnam and determined the average costs as well as the main cost drivers.MethodologyThe full costs of five hospitals were analysed, including depreciation and the value of donations. The costs were allocated to cost centres and cost units by a stepping‐stone method.Major findingsAs expected, the average costs per inpatient day at a central hospital are about 300% of the costs of provincial hospitals and about 600% of the costs of district hospitals. However, the costs of some laboratory procedures and operations done at district hospitals are higher than those of provincial or even central hospitals. The main reason for the high costs of some procedures at district hospitals was the low quantity of these procedures at that level. This is a strong indicator that some procedures, in particular major operations, should not be performed in Vietnamese district hospitals. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of various sterilization methods on the setting and mechanical properties of apatite cement
Authors: Takechi Masaaki , Miyamoto Youji , Momota Yukihiro , Yuasa Tetsuya , Tatehara Seiko , Nagayama Masaru , Ishikawa Kunio 
Published: March 2004

AbstractSterilization capability is a necessary requirement for any material that is to be used in a medical application. Therefore, it is necessary for apatite cement (AC) to be sterilized. Because there is little information on the sterilization methods of AC, the aims of this investigation were to evaluate the effects of various sterilization methods, including steam, dry heat, ethylene oxide (EtO) gas, and gamma irradiation sterilizations, on the setting and mechanical properties of AC. In the case of steam sterilization, because AC powder aggregated before setting‐time measurements, the setting time could not be measured. When the powder was sterilized by dry heat or EtO gas, the setting time was prolonged significantly and the wet diametral tensile strength (DTS) value decreased significantly. Therefore, sterilizations with steam, dry heat, or EtO gas were suggested to be inappropriate methods for AC. Accordingly, the following experiments focused on gamma sterilization. The setting time of AC was retarded with an increase in gamma irradiation dose. The wet DTS value decreased with the increase in gamma irradiation dose. There was no compositional change due to the gamma irradiation. The following tests were carried out in order to examine the effect of the gamma irradiation on the setting reaction of AC in detail. Tetracalcium phosphate [TTCP: Ca4(PO4)2O] and dicalcium phosphate anhydrous (DCPA: CaHPO4) were separately irradiated, and the cements were produced with the use of irradiated powder and nonirradiated powder. Although the wet DTS value of AC produced from irradiated TTCP and nonirradiated DCPA decreased with increasing gamma irradiation dose, there was no significant difference. In contrast, the wet DTS value of AC produced from irradiated DCPA and nonirradiated TTCP significantly decreased with the increase in gamma irradiation dose. In conclusion, although the detailed mechanism of the delayed setting time and decreased DTS value was not clarified by the present study, it was found that gamma irradiation affected DCPA more than TTCP. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 58–63, 2004
Development of medical guide wire of Cu‐Al‐Mn–base superelastic alloy with functionally graded characteristics
Authors: Sutou Yuji , Omori Toshihiro , Furukawa Akihisa , Takahashi Yukinori , Kainuma Ryosuke , Yamauchi Kiyoshi , Yamashita Shuzo , Ishida Kiyohito 
Published: March 2004

AbstractA new type of medical guide wire with functionally graded hardness from the tip to the end was developed with the use of Cu‐Al‐Mn–based alloys. The superelasticity (SE) of the Cu‐Al‐Mn–based alloys in the tip is drastically improved by controlling the grain size, whereas the end of the wire is hardened using bainitic transformation by aging at around 200–400 °C. Therefore, the tip of the guide wire shows a superelasticity and its end has high stiffness. This guide wire with functionally graded characteristics shows excellent pushability and torquability, superior to that of the Ni‐Ti guide wire. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 64–69, 2004
Etched implants: A comparative surface analysis of four implant systems
Authors: Szmukler‐Moncler S. , Testori T. , Bernard J. P. 
Published: March 2004

AbstractSurface texturing by acid etching has recently become popular among dental implant manufacturers. The aim of this study was to compare the surface topography of four implant systems and to check the reproducibility of the industrial process of each implant system. Three implants per system have been selected from three distinct batches. They were observed under a scanning electron microscope (SEM), and roughness was determined with a contact profilometer by measuring five height‐descriptive parameters (Ra, Rq, RzISO, Rt, and Rsk, a texture parameter Sm, and a hybrid parameter RΔq. The analysis showed that each implant system displayed a distinct surface topography that could not be mistaken. When sandblasting was performed prior to etching, surface topography was a combination of macro‐ and microroughness. The roughness and the amount of remaining sand varied among the batches, showing that the industrial process is not fully developed. Deviation from the released technical information was found for two out of four implant manufacturers. Based on the available biological and clinical data on textured surfaces, it is suggested that it is bone interlocking at the interface that maintains the biological properties of textured surfaces, rather than a strong implant fixation per se. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 46–57, 2004
The effect of six years of water storage on resin composite bonding to human dentin
Authors: Frankenberger Roland , Strobel Wolfgang O. , Lohbauer Ulrich , Krämer Norbert , Petschelt Anselm 
Published: March 2004

AbstractThe aim of this in vitro study was to evaluate dentin bond strength and marginal adaptation of direct resin composite fillings after different storage times. Three hundred sixty cavities were prepared in discs of freshly extracted human third molars and filled with resin composites. Multistep self‐etching adhesives (Syntac Classic, A.R.T. Bond, both with and without total etching), three‐step etch‐and‐rinse adhesives (Scotchbond Multi‐Purpose Plus, EBS), and two‐step etch‐and‐rinse adhesives (Prime&Bond 2.0, Syntac Single‐Component) were used for bonding. After 1, 90, and 2190 days of water storage and 24 h thermocycling (1150 cycles), push‐out testing was performed. From the 6‐year group, replicas were made after 1 day, 90 days, and 1, 2, 3, 4, 5, and 6 years, and examined regarding marginal adaptation under an SEM (× 200 magnification). In all groups under investigation, push‐out bond strengths remained stable after 90 days; however, the strengths significantly decreased after 6 years of water storage. The two‐step systems exhibited lower bond strengths than three‐step systems after 6 years. Marginal analysis revealed a significant loss regarding the percentage of perfect margins having been stable after 2 years for the three‐step etch‐and‐rinse systems. Overall, the older three‐step systems proved to be more effective than the simplified adhesives Syntac Single‐Component and Prime&Bond 2.0 with regard to bond strength and marginal adaptation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 25–32, 2004
Apatite formation on the surface of wollastonite/tricalcium phosphate composite immersed in simulated body fluid
Authors: Huang Xiang , Jiang Dongliang , Tan Shouhong 
Published: March 2004

AbstractWollastonite/tricalcium phosphate composites were prepared and immersed in SBF for various periods to investigate the apatite‐formation mechanism on their surfaces. Surface morphologies and composition before and after immersion were analyzed by SEM and EDS technologies. The concentration changes of calcium, silicon, and phosphorus in SBF due to the immersion of the samples were measured with inductively coupled plasma atomic emission spectroscopy, and the corresponding pH values in SBF were recorded. XRD and IR were used to examine the changes in crystalline phases and functional groups. It was found that, after immersion for 1 day, the samples were covered by pom‐pom–like apatite granules, resulting from the dissolution of wollastonite and the simultaneous transformation of TCP. This quickly led to the subsequent precipitation of another apatite layer, which covered the earlier‐formed surface completely. These results indicate that the wollastonite/tricalcium phosphate composite is a potential biomaterial candidate because of its high bioactivity and in situ porous structure. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 70–72, 2004
Protein‐loaded bioresorbable fibers and expandable stents: Mechanical properties and protein release
Authors: Zilberman Meital , Schwade Nathan D. , Eberhart Robert C. 
Published: March 2004

AbstractThere is an increasing interest in bioresorbable polymeric stents for coronary, urethral and tracheal applications. These stents can support body conduits during their healing process and release biologically active agents from an internal reservoir to the surrounding tissue. A removal operation is not needed. Bioresorbable poly(L‐lactic acid) fibers were prepared through melt spinning accompanied by a postpreparation drawing process. Novel expandable bioresorbable stents were developed from these fibers. Bioresorbable microspheres containing albumin were prepared and attached to the stents, to serve as a protein reservoir coating. The controlled release of albumin from the microsphere‐loaded stent was studied. The fibers combine high strength and modulus, together with good ductility and flexibility. An increase in draw ratio increases the tensile strength and modulus and decreases the ultimate strain. The stents demonstrated excellent initial radial compression strength and good in vitro degradation resistivity, which makes them applicable for supporting blood vessels for at least 20 weeks. Microspheres bound to these stents enable effective protein loading, without reducing the stent's mechanical properties. The protein release from the microsphere‐loaded stent occurs by diffusion, is determined mainly by the initial molecular weight of the bioresorbable polymer and its erosion rate, and is strongly affected by the microsphere structure. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 1–10, 2004
Sol‐gel preparation and in vitro test of fluorapatite/hydroxyapatite films
Authors: Cheng Kui , Weng Wenjian , Qu Haibo , Du Piyi , Shen Ge , Han Gaorong , Yang Juan , Ferreira J. M. F. 
Published: March 2004

AbstractFluorapatite/hydroxyapatite (FA/HA) films have been demonstrated to be a good alternative to pure hydroxyapatite (HA) ones in medical applications because of their bioactivity and relatively low solubility. In this study, Ca(NO3)2, P2O5, and HPF6 were used to prepare FA/HA films on Ti6Al4V substrate with the use of a sol‐gel method. The F contents in the films could be tailored by adjusting the amount of HPF6 added. The in vitro evaluation of the films was carried out in both SBF9# solution and TRIS buffer solution. The films with appropriate F contents showed a better ability to induce calcium phosphate deposition on their surfaces than either pure HA film and FA/HA films with even higher F content, as well as smaller dissolution amounts than HA film in TRIS buffer solution. Hence, the FA/HA films obtained in this work integrate both good bioactivity and stability, and could be a better choice for bioactive film on titanium alloys to produce high‐quality implants. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 33–37, 2004
Analysis of cellular morphology, adhesion, and proliferation on uncoated and differently coated PVC tubes used in extracorporeal circulation (ECC)
Authors: Moreira Patrícia da Luz , Marreco Paula Rulf , Moraes Angela Maria , Wada Maria Lúcia Furlan , Genari Selma Candelária 
Published: March 2004

AbstractThe biggest challenge to improve extracorporeal circulation (ECC) circuits lays on avoiding platelet adhesion to their surfaces, because this contributes to thrombus formation, resulting in the activation of blood coagulation. One approach to minimize this effect is to improve the biocompatibility of ECC circuits by modifying their surfaces. This can be achieved by coating them with heparin or phospholipids. The present study investigated the adhesion and morphology characteristics of fibroblastic and blood cells cultured on uncoated poly (vinyl) chloride PVC tubes as well as on heparin, phosphatidylcholine (DMPC), and phosphatidylethanolamine (DMPE) ‐coated tubing. The results showed the importance of uniform coating regardless of the substance used, because the coatings cover the grooves on PVC surfaces, which favor cell adhesion. The comparison among the three different coatings showed the best biocompatibility results for the PVC tubes coated with heparin, followed by the coating with DMPE and with DMPC. For all coated tubes, cells did not spread on the PVC surfaces and, consequently, did not adhere to their surfaces, increasing the overall biocompatibility of PVC tubes. However, possible DMPE′s alkylation, caused by sterilization, resulted in increased material hydrophobicity, which explains the decrease in fibroblastic adhesion. Furthermore, sterilization of DMPC‐PVC improves its hydrophilic character, also decreasing adhesion. Based on these results, coating PVC with the phospholipids DMPC and DMPE seems to be a promising technique to improve the biocompatibility of PVC tubes, and is worthy of further investigation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 38–45, 2004
Sublethal concentrations of Au (III), Pd (II), and Ni(II) differentially alter inflammatory cytokine secretion from activated monocytes
Authors: Wataha John C. , Lewis Jill B. , Volkmann Keith R. , Lockwood Petra E. , Messer Regina L. W. , Bouillaguet Serge 
Published: March 2004

AbstractMany transition metals have been viewed collectively as nonspecific biological toxins in cells, which has limited investigation into their possible therapeutic effects. In the current study, the effects of Au(III), Ni(II), and Pd(II) on the differential secretion of cytokines from monocytes has been investigated. This is critical to understanding any therapeutic potential of these metals, their allergenicity, or the clinical effects of current metal therapies such as chrysotherapy. Lethal concentrations (defined as > 50% suppression of mitochondrial succinate dehydrogenase (SDH) activity) of metals were determined by dose‐response curves with the use of 72 h exposures to human THP‐1 monocytes. Then, secretion of TNFα, IL1β, and IL6 were measured after the monocytes were exposed to sublethal concentrations of metals, with or without stimulation by lipopolysaccharide. The concentrations of Au(III), Pd(II), and Ni(II) required to suppress SDH activity by 50% were found to be 255, 270, and 90 μM, respectively. No sublethal concentration of any metal alone caused secretion of the cytokines. However, LPS‐induced cytokine secretion was significantly and differentially altered by sublethal concentrations of each metal. Differential responses were highly dependent on metal concentration and involved both suppression and potentiation of the LPS activation. In the case of Ni(II), potentiation of TNFα, IL1β, and IL6 ranged from 200% for TNFα to over 1200% for IL6. Metals such as Au(III), Pd(II), and Ni(II) differentially alter cytokine expression from monocytes. These results imply that metals have more specific effects on cell signaling than previously assumed. These results also are important in explaining multiple clinical effects often seen with chrysotherapy, identifying potential new avenues for metal therapy, and understanding the inflammatory effects of metals such as nickel. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 11–17, 2004
Development of a recombinant human collagen‐type III based hemostat
Authors: Yang C. , Hillas P. , Tang J. , Balan J. , Notbohm H. , Polarek J. 
Published: March 2004

AbstractAnimal‐tissue‐derived collagen, containing mostly type I collagen with a minor amount of type III collagen, has been widely used in the production of hemostats for many decades, although it has been known for a long time that type III collagen is more likely to induce platelet aggregation in vitro. Because it is hard to purify type III from animal tissue, it has not been possible to correlate this finding with in vivo data. In this report, it is demonstrated that recombinant human collagen III fibrils are more capable of inducing platelet aggregation in vitro than those comprised of bovine collagen I, in agreement with previously published data on tissue‐derived type III collagen. When formed into three‐dimensional matrices, the use of type III collagen results in formulations with better mechanical integrity, larger surface area, and higher hemostatic activity in a rabbit spleen injury model as compared with commercially available hemostats formed from bovine type I collagen. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 18–24, 2004
Wear‐particle–induced osteoclast osteolysis: The role of particulates and mechanical strain
Authors: MacQuarrie Robyn A. , Fang Chen Ying , Coles Chad , Anderson Gail I. 
Published: March 2004

AbstractPeriprosthetic osteolysis involves osteoclast activation by wear particulates and their exposure to mechanical perturbation through exposure to shear forces generated by periprosthetic fluid as well as interface micromotion. This study aimed to determine the interactions between wear particulates, mechanical stimulation, and osteoclasts. In static cultures, wear particulates increased osteoclast differentiation. Addition of neutralizing antibodies to RANKL (receptor activator of nuclear factor kappa ligand) inhibited the particle‐induced increase in osteoclast numbers. Cyclic 5000 microstrains were applied with the use of a custom‐built device to marrow‐derived cultures to assess the effect on osteoclast differentiation. Mechanical strain application alone decreased osteoclast differentiation, which was further decreased by the addition of particles despite increases in the soluble RANKL to osteoprotegerin (OPG) ratio. Mechanical strain alone induced mature osteoclast apoptosis in a dose‐dependent manner. In contrast, in the mature osteoclast model, the addition of nonmetal particulates protected the osteoclasts from becoming apoptopic. Titanium (Ti) and cobalt chromium (CoCr) particles, however, induced osteoclast apoptosis, whereas polyethylene (PE) and polymethylmethacrylate (PMMA) did not. Wear particulates and mechanical stimulation interact via an eicosanoid‐dependent pathway to alter osteoclast function and survival. The addition of mechanical perturbation to a particle‐laden system thus appears to enhance the potential for osteolytic activity by enhancing osteoclast survival. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 104–112, 2004
The physicochemical properties of the solidification of calcium phosphate cement
Authors: Liu Changsheng , Huang Yue , Chen Jianguo 
Published: March 2004

AbstractIn this article, the physicochemical properties of the solidification of calcium phosphate cement (CPC) were investigated, and the components of the solidified body and the characteristics involved in the application were measured. The setting process of CPC was moderate and slightly exothermic, the heat liberation rate was slow, and the temperature increased little. At the initial stage of the hydration, the compressive strength rose linearly with time, and reached the maximum value after 4 hours. The volume was slightly shrunken by 1% during the setting process, and the total heavy metal content was below 2 ppm. The porosity of the solidified body was about 30%, which was mainly the gel pore with size below 0.1 μm. The final product of hydration was low crystalline hydroxyapatite (HAP). Its real density was 2.859 g/cm3, which was lower than the theoretical value. This may be due to the existence of lattice defects, which will lead to a slight rise in solubility when leached in physiological saline. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 73–78, 2004