bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of stochastic demand and expense preference behaviour on public hospital costs and excess capacity
Authors: Lovell C. A. Knox , Rodríguez‐Álvarez Ana , Wall Alan 
Published: April 2008

AbstractThe literature to date on the effect of demand uncertainty on public hospital costs and excess capacity has not taken into account the role of expense preference behaviour. Similarly, the research on expense preference behaviour has not taken demand uncertainty into account. In this paper, we argue that both demand uncertainty and expense preference behaviour may affect public hospital costs and excess capacity and that ignoring either of these effects may lead to biased parameter estimates and misleading inference. To show this, we extend the analysis of Rodríguez‐Álvarez and Lovell (Health Econ. 2004; 13: 157–169) by incorporating demand uncertainty into the technology to account for the hospital activity of providing standby capacity or insurance against the unexpected demand. We find that demand uncertainty in Spanish public hospitals affects hospital production decisions and increases costs. Our results also show that overcapitalization in these hospitals can be explained by hospitals providing insurance demand when faced with demand uncertainty. We also find evidence of expense preference behaviour. We conclude that both stochastic demand and expense preference behaviour should be taken into account when analysing hospital costs and production. Copyright © 2008 John Wiley & Sons, Ltd.
Globally optimal trial design for local decision making
Authors: Eckermann Simon , Willan Andrew R. 
Published: April 2008

AbstractValue of information methods allows decision makers to identify efficient trial design following a principle of maximizing the expected value to decision makers of information from potential trial designs relative to their expected cost. However, in health technology assessment (HTA) the restrictive assumption has been made that, prospectively, there is only expected value of sample information from research commissioned within jurisdiction. This paper extends the framework for optimal trial design and decision making within jurisdiction to allow for optimal trial design across jurisdictions. This is illustrated in identifying an optimal trial design for decision making across the US, the UK and Australia for early versus late external cephalic version for pregnant women presenting in the breech position. The expected net gain from locally optimal trial designs of US$0.72M is shown to increase to US$1.14M with a globally optimal trial design. In general, the proposed method of globally optimal trial design improves on optimal trial design within jurisdictions by: (i) reflecting the global value of non‐rival information; (ii) allowing optimal allocation of trial sample across jurisdictions; (iii) avoiding market failure associated with free‐rider effects, sub‐optimal spreading of fixed costs and heterogeneity of trial information with multiple trials. Copyright © 2008 John Wiley & Sons, Ltd.
Potential barriers to the application of multi‐factor portfolio analysis in public hospitals: evidence from a pilot study in the Netherlands
Authors: Pavlova Milena , Tsiachristas Apostolos , Vermaeten Gerhard , Groot Wim 
Published: April 2008

AbstractPortfolio analysis is a business management tool that can assist health care managers to develop new organizational strategies. The application of portfolio analysis to US hospital settings has been frequently reported. In Europe however, the application of this technique has received little attention, especially concerning public hospitals. Therefore, this paper examines the peculiarities of portfolio analysis and its applicability to the strategic management of European public hospitals. The analysis is based on a pilot application of a multi‐factor portfolio analysis in a Dutch university hospital. The nature of portfolio analysis and the steps in a multi‐factor portfolio analysis are reviewed along with the characteristics of the research setting. Based on these data, a multi‐factor portfolio model is developed and operationalized. The portfolio model is applied in a pilot investigation to analyze the market attractiveness and hospital strengths with regard to the provision of three orthopedic services: knee surgery, hip surgery, and arthroscopy. The pilot portfolio analysis is discussed to draw conclusions about potential barriers to the overall adoption of portfolio analysis in the management of a public hospital. Copyright © 2008 John Wiley & Sons, Ltd.
Cancer risk in people infected with human immunodeficiency virus in the United States
Authors: Engels Eric A. , Biggar Robert J. , Hall H. Irene , Cross Helene , Crutchfield Allison , Finch Jack L. , Grigg Rebecca , Hylton Tara , Pawlish Karen S. , McNeel Timothy S. , Goedert James J. 
Published: April 2008

AbstractData are limited regarding cancer risk in human immunodeficiency virus (HIV)‐infected persons with modest immunosuppression, before the onset of acquired immunodeficiency syndrome (AIDS). For some cancers, risk may be affected by highly active antiretroviral therapy (HAART) widely available since 1996. We linked HIV/AIDS and cancer registries in Colorado, Florida and New Jersey. Standardized incidence ratios (SIRs) compared cancer risk in HIV‐infected persons (initially AIDS‐free) during the 5‐year period after registration with the general population. Poisson regression was used to compare incidence across subgroups, adjusting for demographic factors. Among 57,350 HIV‐infected persons registered during 1991–2002 (median CD4 count 491 cells/mm3), 871 cancers occurred during follow‐up. Risk was elevated for Kaposi sarcoma (KS, SIR 1,300 [n = 173 cases]), non‐Hodgkin lymphoma (NHL, 7.3 [n = 203]), cervical cancer (2.9 [n = 28]) and several non‐AIDS‐defining malignancies, including Hodgkin lymphoma (5.6 [n = 36]) and cancers of the lung (2.6 [n = 109]) and liver (2.7 [n = 14]). KS and NHL incidence declined over time but nonetheless remained elevated in 1996–2002. Incidence increased in 1996–2002 compared to 1991–1995 for Hodgkin lymphoma (relative risk 2.7, 95%CI 1.0–7.1) and liver cancer (relative risk infinite, one‐sided 95%CI 1.1‐infinity). Non‐AIDS‐defining cancers comprised 31.4% of cancers in 1991–1995, versus 58.0% in 1996–2002. For KS and NHL, risk was inversely related to CD4 count, but these associations attenuated after 1996. We conclude that KS and NHL incidence declined markedly in recent years, likely reflecting HAART‐related improvements in immunity, while incidence of some non‐AIDS‐defining cancers increased. These trends have led to a shift in the spectrum of cancer among HIV‐infected persons. © 2008 Wiley‐Liss, Inc.
Mechanical behavior of human cortical bone in cycles of advancing tensile strain for two age groups
Authors: Nyman Jeffry S. , Roy Anuradha , Reyes Michael J. , Wang Xiaodu 
Published: April 2008

AbstractThe capacity of bone for post‐yield energy dissipation decreases with age. To gain information on the causes of such a change, we examined age‐related changes in the mechanical behavior of human cadaveric bone as a function of progressive deformation. In this study, tensile specimens from tibiae of nine middle aged and eight elderly donors were loaded till failure in an incremental and cyclic (load‐dwell‐unload‐dwell‐reload) scheme. The elastic modulus, maximum stress, permanent strain, stress relaxation, permanent strain energy, elastic release strain energy, and hysteresis energy were determined in each loading cycle at incremental strains. Similar with previous work, the results of the present study also indicated that elderly bone failed at much lower strains compared to middle aged bone. However, no significant differences in the mechanical behavior of bone were observed between the two age groups except for the premature failure of elderly bone. After yielding, the energy dissipation and permanent strain of bone appeared to linearly increase with increasing strain applied, while nonlinear changes occurred in the modulus loss and stress relaxation with increasing strain. Moreover, stress relaxation tended to peak at 1% strain beyond which few elderly bone specimens survived. This study suggests that damaging mechanisms in bone vary with deformation, and aging affects the post‐yield mechanisms, thus giving rise to the age‐related differences in the mechanical properties of bone, especially the capacity of the tissue for energy dissipation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Paracrine and juxtacrine lymphocyte enhancement of adherent macrophage and foreign body giant cell activation
Authors: Chang David T. , Colton Erica , Anderson James M. 
Published: April 2008

AbstractLymphocytes have been shown to be involved in modulating monocyte and macrophage behavior in the foreign body reaction. Lymphocyte effects on biomaterial‐adherent macrophage and foreign body giant cell (FBGC) behavior were further investigated by culturing monocytes alone or together with lymphocytes, either in direct co‐cultures or indirectly in transwells, on a series of polyethylene terephthalate‐based photograft co‐polymerized material surfaces displaying distinct hydrophobic, hydrophilic/neutral, hydrophilic/anionic, and hydrophilic/ cationic chemistries. After periods of 3, 7, and 10 days, cytokine production was quantified by enzyme‐linked immunosorbent assay and normalized to adherent macrophage/FBGC density to yield a measure of adherent macrophage/FBGC activation. Interactions with lymphocytes enhanced adherent macrophage and FBGC production of pro‐inflammatory IL‐1β, TNF‐α, IL‐6, IL‐8, and MIP‐1β on the hydrophobic and hydrophilic/cationic surfaces but had no effect on anti‐inflammatory IL‐10 production indicating lymphocytes promote a pro‐inflammatory response to biomaterials. Lymphocytes also did not significantly influence MMP‐9, TIMP‐1, and TIMP‐2 production. Interactions through indirect (paracrine) signaling showed a significant effect in enhancing adherent macrophage/FBGC activation at early time points whereas interactions via direct (juxtacrine) mechanisms dominated at later time points. Biomaterial surface chemistries differentially affected the observed responses as hydrophilic/neutral and hydrophilic/anionic surfaces, evoked the highest levels of activation relative to the other surfaces but did not facilitate lymphocyte enhancement of adherent macrophage/FBGC activation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
L929 fibroblast and Saos‐2 osteoblast response to hydroxyapatite‐βTCP/agarose biomaterial
Authors: Alcaide María , Serrano M. Concepcion , Pagani Raffaella , Sánchez‐Salcedo Sandra , Nieto Alejandra , Vallet‐Regí María , Portolés M. Teresa 
Published: April 2008

AbstractBiphasic calcium phosphate, a mixture of hydroxyapatite (HA) and β‐tricalcium phosphate (β‐TCP), has been successfully used as an excellent bone graft substitute because of the HA capacity for direct interaction with bone and the β‐TCP resorption properties. Agarose has been recently mixtured with ceramics as natural biodegradable binder to increase the biomaterial flexibility facilitating its placement into the bone defect. In this study, the behavior of L929 fibroblasts and Saos‐2 osteoblasts cultured on hydroxyapatite‐βTCP/agarose disks has been evaluated. Both cell types adhere and proliferate on the biomaterial surface maintaining their characteristic morphology. Transitory changes on cell cycle, size, and complexity are observed. The biomaterial induces apoptosis in Saos‐2 osteoblasts but not in fibroblasts. A transitory stimulation of fibroblast mitochondrial activity is observed. This effect remains in osteoblasts after 9 days of culture showing a higher sensitivity of this cell type. However, the intracellular reactive oxygen species content and the lactate dehydrogenase release of Saos‐2 osteoblasts indicate that hydroxyapatite‐βTCP/agarose does not induce oxidative stress in this cell type and confirm the integrity of the osteoblast plasma membrane. These results underline the good biocompatibility of hydroxyapatite‐βTCP/agarose disks and its potential utility for bone substitution and repair. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Chemical and topographical influence of hydroxyapatite and β‐tricalcium phosphate surfaces on human osteoblastic cell behavior
Authors: dos Santos E. A. , Farina M. , Soares G. A. , Anselme K. 
Published: April 2008

AbstractThe objective of this work was to evaluate the relative role of the calcium phosphate surface chemistry and surface topography on human osteoblast behavior. Highly dense phosphate ceramics (single‐phase hydroxyapatite HA and β‐tricalcium phosphates TCP) presenting two distinct nano roughnesses were produced. Some samples were gold‐sputter coated in order to conveniently mask the surface chemical effects (without modification of the original roughness) and to study the isolated effect of surface topography on cellular behavior. Our results indicated that the nanotopography of the studied ceramics had no effect on the cellular adhesion (cell spreading, focal contacts and stress fibers formation). On the contrary, strong topographical effects were verified on cell proliferation and differentiation. Moreover, the phosphate chemistry was responsible for changes in adhesion, proliferation and cell differentiation. On TCP, it was shown that the main influent parameter was surface chemistry, which negatively affected the initial cell adhesion but positively affected the subsequent stage of proliferation and differentiation. On HA, the main influent parameter was surface topography, which increased cell differentiation but lowered proliferation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
On the assessment of oxidative and microstructural changes after in vivo degradation of historical UHMWPE knee components by means of vibrational spectroscopies and nanoindentation
Authors: Medel Francisco J. , Rimnac Clare M. , Kurtz Steven M. 
Published: April 2008

AbstractThis study reports on the suitability of different experimental techniques to evaluate chemical, microstructural, and mechanical changes associated with in vivo oxidation encountered in historical polyethylene components. To accomplish this aim, eight traceable tibial inserts were analyzed after revision surgery. The knee bearings were γ sterilized in air and implanted for an average of 11.5 years after a shelf life of no longer than 1 year. Characterization of oxidation and transvinylene indexes, crystallinity, amorphous, and intermediate phase fractions, along with hardness and surface modulus, were performed in transverse sections of each bearing using Fourier transform infrared spectroscopy, Raman spectroscopy, and nanoindentation, respectively. Generally, subsurface maxima in the crystallinity, oxidation index, and hardness were observed at a depth of about 1 mm in all of the bearings. The superior surfaces and anterior‐posterior faces of the inserts exhibited significantly higher oxidation and greater crystallinity than the inferior side. These observations suggest that the metallic tray may limit the access of molecular oxygen to the backside of the tibial inserts. We conclude that chemical, physical, and mechanical properties data confirm the occurrence of in vivo degradation in the long‐term implanted knee components following γ irradiation in air. Furthermore, infrared spectroscopy alone appeared to provide excellent insight into the oxidation and crystallization state of the in vivo oxidized polyethylene. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
The modification of PLA and PLGA using electron‐beam radiation
Authors: Leonard Dermot J. , Pick Louise T. , Farrar David F. , Dickson Glenn R. , Orr John F. , Buchanan Fraser J. 
Published: April 2008

AbstractThe degradable polymers polylactide (PLA) and polylactide‐co‐glycolide (PLGA) have found widespread use in modern medical practice. However, their slow degradation rates and tendency to lose strength before mass have caused problems. The aim of this study was to ascertain whether treatment with e‐beam radiation could address these problems. Samples of PLA and PLGA were manufactured and placed in layered stacks, 8.1 mm deep, before exposure to 50 kGy of e‐beam radiation from a 1.5 MeV accelerator. Gel permeation chromatography testing showed that the molecular weight of both materials was depth‐dependent following irradiation, with samples nearest to the treated surface showing a reduced molecular weight. Samples deeper than 5.4 mm were unaffected. Computer modeling of the transmission of a 1.5 MeV e‐beam in these materials corresponded well with these findings. An accelerated mass‐loss study of the treated materials found that the samples nearest the irradiated surface initiated mass loss earlier, and at later stages showed an increased percentage mass loss. It was concluded that e‐beam radiation could modify the degradation of bioabsorbable polymers to potentially improve their performance in medical devices, specifically for improved orthopedic fixation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Anticoagulant surface modification of titanium via layer‐by‐layer assembly of collagen and sulfated chitosan multilayers
Authors: Li Quan‐Li , Huang Nan , Chen Jialong , Wan Guojiang , Zhao Ansa , Chen Junying , Wang Jin , Yang Ping , Leng Yongxiang 
Published: April 2008

AbstractExtracellular matrix (ECM)‐like biomimetic surface modification of cardiovascular implants is a promising method for improving hemocompatibility. In the present work, collagen (Col) and sulfated chitosan (SCS) multilayers were coated on pure titanium using a layer‐by‐layer (LBL) self‐assembly technique. The Col‐SCS multilayer growth was carried out by first depositing a single layer of positively charged poly‐L‐lysine (PLL) on the NaOH‐treated titanium substrate (negatively charged surface), followed by alternate deposition of negatively charged SCS and positively charged Col, and terminated by an outermost layer of SCS. Platelet adhesion in vitro, partial activated thromboplastin time (APTT) and prothrombin time (PT) assays were used to evaluate the hemocompatibility of the Col‐SCS multilayer coated titanium. The multilayer processed surfaces displayed reduced platelet adhesion and activation, and prolonged clotting time of APTT and PT compared with untreated titanium. Thus, the approach described here may provide a basis for the preparation of modified titanium surfaces for application in cardiovascular implants. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Distribution of lipid nanocapsules in different cochlear cell populations after round window membrane permeation
Authors: Zou Jing , Saulnier Patrick , Perrier Thomas , Zhang Ya , Manninen Tommi , Toppila Esko , Pyykkö Ilmari 
Published: April 2008

AbstractHearing loss is a major public health problem, and its treatment with traditional therapy strategies is often unsuccessful due to limited drug access deep in the temporal bone. Multifunctional nanoparticles that are targeted to specified cell populations, biodegradable, traceable in vivo, and equipped with controlled drug/gene release may resolve this problem. We developed lipid core nanocapsules (LNCs) with sizes below 50 nm. The aim of the present study is to evaluate the ability of the LNCs to pass through the round window membrane and reach inner ear targets. FITC was incorporated as a tag for the LNCs and Nile Red was encapsulated inside the oily core to assess the integrity of the LNCs. The capability of LNCs to pass through the round window membrane and the distribution of the LNCs inside the inner ear were evaluated in rats via confocal microscopy in combination with image analysis using ImageJ. After round window membrane administration, LNCs reached the spiral ganglion cells, nerve fibers, and spiral ligament fibrocytes within 30 min. The paracellular pathway was the main approach for LNC penetration of the round window membrane. LNCs can also reach the vestibule, middle ear mucosa, and the adjacent artery. Nuclear localization was detected in the spiral ganglion, though infrequently. These results suggest that LNCs are potential vectors for drug delivery into the spiral ganglion cells, nerve fibers, hair cells, and spiral ligament. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Injectability of a bone filler system based on hydroxyapatite microspheres and a vehicle with in situ gel‐forming ability
Authors: Oliveira Serafim M. , Barrias Cristina C. , Almeida Isabel F. , Costa Paulo C. , Ferreira Maria R. Pena , Bahia Maria F. , Barbosa Mário A. 
Published: April 2008

AbstractThe aim of this study was to test the injectability of a bone filler system based on the combination of ceramic microspheres with a gel‐like vehicle, for noninvasive surgery. Porous hydroxyapatite microspheres with a uniform size and an average diameter of 535 ± 38 μm were prepared, and their compression strength and friability were tested. The sodium‐alginate solution with a concentration of 7.25% (w/v) was used as the vehicle. To promote its in situ gelation, calcium carbonate and D‐gluconic‐δ‐lactone were added to the solution. Microspheres were mixed with the vehicle at different percentages (20–40 wt %). Gelation times in the range of 8–20 min, were obtained, depending on the formulation. Mixtures of HAp microspheres with alginate solution at 7.25% originating a gel in 11 min present an adequate handling time to perform an injection. Their injectability was evaluated using an injection device commonly employed in vertebroplasty surgical procedures, coupled to a texturometer in compression mode. Using an extrusion rate of 0.1 mm/s, the force required to extrude any of the mixtures tested was lower than 100 N. For an extrusion rate of 1 mm/s mixtures with 40 wt % of microspheres were very difficult to inject. Mixtures with 35 wt % of microspheres presented the best compromise between injectability and compression strength of the gelled system. MicroCT analysis revealed a homogeneous distribution of the microspheres inside the vehicle, as well as full interconnection of the intra‐microspheres spaces. The compression strength for the gelled systems ranged from 80 kPa (gel itself) to 600 kPa (composite with 40 wt % of microspheres). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008