bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet responses and coagulation activation on polylactide and heparin–polycaprolactone‐L‐lactide ‐coated polylactide stent struts
Authors: Hietala Eeva‐Maija , Maasilta Paula , Välimaa Tero , Harjula Ari L.J. , Törmälä Pertti , Salminen Ulla‐Stina , Lassila Riitta 
Published: November 2003

AbstractDespite modern stent technology and effective antiplatelet therapy, metallic stents carry the risk of (sub)acute thrombosis. Our aim was to examine short‐term differences in platelet deposition and coagulation activation between biodegradable polylactide (PLA), heparin–polycaprolactone‐L‐lactide‐coated polylactide (hepa‐P(CL95/L‐LA5)‐PLA), and stainless steel (SS) stent struts. Gel‐filtered platelets (GFP) and platelet‐rich plasma (PRP) were labeled with 10 nM 3H‐serotonin. Platelet deposition was measured after incubation of the stent struts in human serum albumin‐coated wells at 37°C in either GFP or PRP. Platelet morphology was studied by scanning electron microscopy (SEM). For coagulation activation, the stent struts were incubated in either PRP or platelet‐poor plasma (PPP), anticoagulated with D‐phenylalanyl‐L‐prolyl‐L‐arginine chloromethyl ketone (PPACK), followed by measurement of fibrinogen, thrombin time (TT), prothrombin fragment 1+2 (F1+2), and thrombin‐antithrombin complex (TAT). SS showed adherence of larger amounts of GFPs than did PLA at a platelet density of 300 × 106/mL (p < 0.05). Furthermore, representative SEM studies showed more platelet spreading on SS than on PLA stent struts. Between PLA and SS, coagulation activity did not differ at any assessment. Based on prolonged TT values in plasma, the heparin coating strongly inhibited coagulation (p < 0.05). The values of soluble TAT and F1+2 for PLA were similar to those of controls, i.e., to incubated suspensions without a stent strut. In conclusion, when compared with stainless steel, both PLA and hepa‐P(CL95/L‐LA5)‐PLA appear hemocompatible as intravascular stent materials. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 785–791, 2003
Fracture of ceramic/ceramic/polymer trilayers for biomechanical applications
Authors: Deng Yan , Miranda Pedro , Pajares Antonia , Guiberteau Fernando , Lawn Brian R. 
Published: November 2003

AbstractFracture damage in trilayers consisting of outer and inner brittle layers bonded to a compliant (polycarbonate) substrate and subjected to concentrated surface loading is analyzed. The principal mode of fracture is radial cracking at the undersurface of the inner (core) layer, even in the strongest of core ceramics—other damage modes, including radial cracking in the outer (veneer) layer, are less invasive in these all‐brittle coating systems. Tests on simple trilayer structures fabricated from glasses, sapphire, and dental ceramics are used to examine the dependence of the critical load for radial fracture in terms of relative outer/inner layer thickness and modulus, and inner layer strength. An explicit relation for the critical load, based on a flexing plate model in which the outer/inner bilayer is reduced to an “equivalent” monolithic coating with “effective” composite modulus, is used to examine these dependencies. The theoretical relation describes all the major trends in the critical load data over a broad range of variables, thus providing a sound basis for trilayer design. Relevance of the analysis to dental crowns and other biomechanical applications is a central theme of the study. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 828–833, 2003
Interactions of corneal cells with transforming growth factor β2‐modified poly dimethyl siloxane surfaces
Authors: Merrett K. , Griffith C.M. , Deslandes Y. , Pleizier G. , Dubé M.A. , Sheardown H. 
Published: November 2003

AbstractThe downgrowth of corneal epithelial cells at the interface of an artificial cornea and the host eye tissue poses a significant problem to be overcome in developing a successful implant. As a means of inhibiting the proliferation of corneal epithelial cells on the stromal surface of the implant, we examined the immobilization of transforming growth factor beta‐2 (TGF‐β2) via a bifunctional poly ethylene glycol (PEG) spacer to poly dimethyl siloxane (PDMS) surfaces. Growth factor immobilization was confirmed by modification with 125I‐labeled TGF‐β2. The modified surfaces were also characterized by advancing water contact angles, X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Although the amount of growth factor covalently bound to the surface was difficult to quantify apparently due to strong interactions between the growth factor and the PEG layer and high levels of adsorption, differences in the modified surfaces, suggestive of the presence of a significant amount of TGF‐β2, were found. In vitro interactions of the modified surfaces with human corneal epithelial and stromal cells were examined. Growth factor surface concentrations as well as culture in the absence and presence of serum and other adhesive proteins were examined. Corneal stromal and epithelial cells cultured on the TGF‐β2—modified surfaces consistently gave results opposite to those expected. Likely, the most notable and surprising result was the almost complete lack of adhesion of the stromal cells, with coverages averaging between 3 and 5%. In comparison, corneal epithelial cell growth appeared to be promoted by the presence of the immobilized growth factor, with cell coverages averaging 50–60% at 7 days of culture. A TGF‐β2 concentration effect was noted with both cell types in the absence of serum, with increases in the coverage at higher TGF‐β2 concentrations. The observed cell growth appeared to be the result of interactions between the cells and active growth factor, because the addition of anti‐TGF‐β2 to the culture medium reduced cell coverage to levels similar to those noted on control surfaces. Therefore, although TGF‐β2–modified surfaces may not be suitable as corneal epithelial cell inhibiting surfaces, interactions of surface immobilized growth factor and corneal cells are complex and should be further examined. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 981–993, 2003
Determination of specific interactions between glucose ligand carrying polymer and glucose transporter type‐1 (GLUT‐1) using different cell types
Authors: Chung Jong‐Hoon , Park Keun‐Hong , Seo Byong‐Moo , Kim Eun‐Seok , Hong Jong‐Rak , Chung Il‐Hyuk , Kang Nara , Baek Jeong‐Hwa , Min Byung‐Moo , Choung Yun‐Hoon , Akaike Toshihiro , Choung Pill‐Houng 
Published: November 2003

AbstractIn order to develop a biomimetic polymer for cell recognition, poly [3‐O‐(4′‐vinylbenzyl)‐D‐glucose] (PVG) and different types of glucose transport (GLUT)‐carrying cells, namely, HepG2 cells (GLUT‐1), 3T3‐L1 fibroblast cells (GLUT‐1 and GLUT‐4), and MIN6 cells (GLUT‐2), were tested for specific interaction. To clarify the nature of interaction between PVG and the different cell types, rhodamine‐B isothiocyanate (RITC)‐labeled polymers were used to prove and visualize the interactions. In this study, we found that labeled polymer strongly binds to HepG2 cells. The fluorescence intensity of PVG with in the presence of HepG2 cells was found to be stronger than that of 3T3‐L1 fibroblast cells (0.11 ± 0.05) and MIN6 cells, which carry GLUT‐2 (0.028 ± 0.01); a confocal laser microscopic study confirmed this interaction. To confirm the specificity of the interaction mediated by GLUT, the cells were pretreated with phloretin, an inhibitor of GLUT‐1, before adding RITC‐labeled PVG polymer to the cell culture medium. This treatment suppressed the interaction of PVG with HepG2 cells and partially suppressed its interaction with 3T3‐L1 fibroblast cells. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1055–1059, 2003
Pore size in implanted polypropylene filters is critical for tissue organization
Authors: Rosengren Agneta , Bjursten Lars Magnus 
Published: November 2003

AbstractWidely different implant materials induce surprisingly similar tissue reactions invivoin contrast to theirin vitroresponses. Increasing attention has recently been given to the surface texture of the material. When both the material composition and the surface topography are varied, the surface topography seems to be the predominant factor for the induced tissue response. The present study addresses differences in the tissue response to commercially available Millipore mesh filters of polypropylene with pore sizes of 0.6, 10.0 or 30.0 μm. The Millipore filters with adjacent tissue were directly sectioned in a cryostat and evaluated via an immunofluorescence technique with double and triple staining, allowing simultaneous analysis of different antigens in tissue sections. These results show that macrophages, total cells, necrotic cells, nitric oxygen distribution, early angiogenesis, and capsule thickness were influenced by the surface structure. Implants with pore sizes of 0.6 μm, where entrance of inflammatory cells was inhibited, induce the most pronounced foreign body capsule formation. The 10‐ and 30‐μm filters, in contrast, had large amounts of macrophages inside the filter structure, although very few inflammatory cells were found outside the filters. The inflammatory cells within the filters appeared not to influence the foreign body capsule induction. The critical factor for the formation of a foreign body capsule seems to be the localization of implant‐close macrophages. Whether this is due to differences in cell activation or in signal transduction to collagen‐synthesizing fibroblasts remains an open question. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 918–926, 2003
Cellular response to calcium phosphate glasses with controlled solubility
Authors: Navarro Melba , Ginebra Maria‐Pau , Planell Josep A. 
Published: November 2003

AbstractIn the last decades, the research on materials for bone regeneration has focused on materials that are degradable and capable of stimulating tissue regeneration. In this context, phosphate glasses offer an interesting alternative, given the wide range of solubility they present and their similarity with respect to the chemical composition of the bone mineral phase. In the current work, two different formulations of phosphate glasses in the system P2O5CaONa2OTiO2 are developed. The incorporation of TiO2 into the glass network allows for better control of the glass dissolution rate. Although these glasses have been studied extensively from the physicochemical point of view, little is known about their biocompatibility. To evaluate the biological response to these materials, we have used a human skin fibroblast model. The cells were incubated in vitro following two different methods. The first was incubated in direct contact with the glasses and the second one, in the presence of their extracts. The effects of the materials on cell growth were determined by means of toxicity (WST assay), adhesion, and proliferation tests. The results showed that the in vitro behavior of soluble phosphate glasses is strongly affected by their solubility. On the other hand, the results showed that the cellular response is highly affected by the testing procedure. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1009–1015, 2003
Inclusion–exclusion in public policies and policy analyses: the case of Philippine land reform, 1972–2002
Authors: Borras Saturnino M. 
Published: November 2003

AbstractMost policy analyses, especially those on land reform, focus on issues and data that are within the official policy scope. This ‘policy scope‐centered’ approach has led to only partial understanding of policy choices, implementation and outcomes. A more complete, and so more powerful, analysis requires the inclusion of issues and data that are excluded from the policy scope. This paper is a preliminary inquiry into the inclusion–exclusion question in the official scope of Philippine land reform policy. It is an initial attempt to raise new questions for further research, and suggests a different strategy for approaching land reform data. Copyright © 2003 John Wiley & Sons, Ltd.
The private sector and water and sanitation services—policy and poverty issues
Authors: Carter Richard C. , Danert Kerstin 
Published: November 2003

AbstractPoor access to water and sanitation is a major poverty issue affecting a large part of the developing world. In their urgency to meet internationally agreed water and sanitation targets, Governments and International Agencies seek new ways and means, including increased use of the private sector. Commercial participation in the water sector is not without vociferous critics, as well as strong proponents. Even accepting the international water and sanitation targets for service coverage—and these authors question their feasibility—it seems clear that no single player in the partnership between public sector, private sector and communities can be responsible for achieving them. Each player has individual roles and requirements, and the strengths of each are needed. Dogmatic promotion or rejection of ‘privatization’ is unhelpful. We appeal to the politically naïve to try to understand privatization's opponents, and for those who protest against the ‘commodification’ of water to shelve their dogmas as they join the common pursuit of permanently improved services for the poor. Copyright © 2003 John Wiley & Sons, Ltd.
The private sector in rural water and sanitation services in Uganda: understanding the context and developing support strategies
Authors: Danert Kerstin , Carter Richard C. , Rwamwanja Ronnie , Ssebalu Jamil , Carr Graham , Kane David 
Published: November 2003

AbstractThis article analyses private sector delivery of water and sanitation services in Uganda. Uganda's policies of decentralization and privatization, combined with enhanced sector funding through debt relief, provide the context for the work described. After a brief description of the attributes of small water sector enterprises, the findings of extensive interviews with all the major stakeholders in eight of Uganda's 56 districts are set out under eight thematic headings (corruption; community participation; role of NGOs; private sector support services; networks and associations; local Government procurement procedures; construction quality; business viability) and two sets of root causes. The paper concludes that a sector strategy requires a limited number of focus areas in order to avoid overwhelming the institutions and local ownership. The strategy should lie between the extremes of prescriptive and process oriented approaches. Monitoring mechanisms should balance quantitative with qualitative data. Finally, a balance is needed between the drive for short‐term impact through physical outputs and the long‐term sustainability of water and sanitation services so delivered. Copyright © 2003 John Wiley & Sons, Ltd.
Public–private partnerships in water: a South African perspective on the global debate
Authors: Muller Mike 
Published: November 2003

AbstractDespite widespread consensus on the importance of meeting the basic human rights of all people for safe water and adequate sanitation, the debate on the role of the private sector is loud, and at times destructive. In South Africa the gross inequalities inherited with the end of apartheid in 1994 drive the strategies of the Department of Water Affairs and Forestry (DWAF). Government policy has deliberately avoided adopting a particular stance on privatization, preferring to focus on the goal rather than the instrument. Nevertheless it has been recognized that a strong public sector is needed. Experience is showing that there are roles for a wide variety of public, private and civil society partners. South Africa could not have achieved what it has since 1994, were it not for a well developed private sector capacity. However, criticism of private sector operation has been noisy. Protest against ‘commoditization’ and pricing of water has been particularly vociferous. In the attempt to enter into dialogue with the critics, the importance of consensus in society has been highlighted. South Africa's inequalities are mirrored on a global scale and its experience is thus relevant to the global water policy debate. The involvement of the private sector should not be forced through global agreements such as GATS or loan conditionality, and international finance should put the poor first. Copyright © 2003 John Wiley & Sons, Ltd.
Flow of funds: implications for research on financial sector development and the real economy
Authors: Green Christopher J. , Murinde Victor 
Published: November 2003

AbstractThis paper provides a selective survey of the leading theoretical and empirical issues surrounding the flow of funds: its meaning and origin, problems of construction, its use in financial modelling and its role as a tool of analysis of intersectoral financial flows. It is argued that there is an intimate connection between the flow of funds, interest rates and asset prices, and hence incomes and expenditures in an economy. The paper discusses flow of funds analysis in the context of developing countries, concentrating on possible applications and methodologies, and the issue of data collection and organization. We explore the reasons for lack of success at empirical flow of funds modelling and propose ‘promising research ideas’ (PRIs) to apply flow of funds analysis to study the relationship between financial sector development and the real economy, particularly to identify effective financial sector policies in developing countries. Copyright © 2003 John Wiley & Sons, Ltd.
Retention modeling and simultaneous optimization of pH value and gradient steepness in RP‐HPLC using feed‐forward neural networks
Authors: Shan Yichu , Zhao Ruihuan , Zhang Yukui , Zhang Weibing , Tian Yan 
Published: November 2003

AbstractA novel approach is proposed for the simultaneous optimization of mobile phase pH and gradient steepness in RP‐HPLC using artificial neural networks. By presetting the initial and final concentration of the organic solvent, a limited number of experiments with different gradient time and pH value of mobile phase are arranged in the two‐dimensional space of mobile phase parameters. The retention behavior of each solute is modeled using an individual artificial neural network. An “early stopping” strategy is adopted to ensure the predicting capability of neural networks. The trained neural networks can be used to predict the retention time of solutes under arbitrary mobile phase conditions in the optimization region. Finally, the optimal separation conditions can be found according to a global resolution function. The effectiveness of this method is validated by optimization of separation conditions for amino acids derivatised by a new fluorescent reagent.
Comparison of silylation and esterification/acylation procedures in GC‐MS analysis of amino acids
Authors: Sobolevsky Tim G. , Revelsky Alexander I. , Miller Barbara , Oriedo Vincent , Chernetsova Elena S. , Revelsky Igor A. 
Published: November 2003

AbstractThree derivatization agents used in GC analysis of amino acids were compared: N,O‐bis(trimethylsilyl)trifluoroacetamide, (BSTFA), N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA), and isobutyl chloroformate (iBuCF). It was shown that the analytical characteristics achieved in the case of silylation with MTBSTFA are comparable to those obtained for esterification/acylation. However, since the former approach requires laborious sample preparation to isolate the compounds in question prior to derivatization, determination of amino acids as N(O,S)‐alkoxycarbonyl alkyl esters seems to be preferable in many cases. Application of the esterification/acylation procedure to analysis of lyophilized E. coli microbial culture was demonstrated.
Simultaneous determination of theophylline, tolbutamide, mephenytoin, debrisoquin, and dapsone in human plasma using high‐speed gradient liquid chromatography/tandem mass spectrometry on a silica‐based monolithic column
Authors: Chen Yu‐Luan , Junga Heiko , Jiang Xiangyu , Naidong Weng 
Published: November 2003

AbstractTheophylline, tolbutamide, mephenytoin, debrisoquin, and dapsone are marker substrates for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, respectively. A silica‐based monolithic column (Chromolith SpeedROD RP‐18e, 50×4.6 mm) was used to separate these five marker substrates of cytochrome P450 within only 84 s. Linear gradient elution was from acetonitrile‐water‐formic acid (10 : 90 : 1, v/v/v) to acetonitrile‐water‐formic acid (90 : 10 : 1, v/v/v) in 1.4 min. The flow rate was 2.5 mL/min. The retention time was 0.52 min for theophylline, 0.67 min for debrisoquin, 0.78 min for dapsone, 0.96 min for mephenytoin, and 1.13 min for tolbutamide. Detection was by tandem mass spectrometry using a PE Sciex API 3000 mass spectrometer with a Turbo‐Ionspray source in positive mode. A simple protein precipitation method was used. This method was validated over the concentration range of 5–2000 ng/mL based on the sample volume of 0.1 mL.
Concurrent solvent recondensation large sample volume splitless injection
Authors: Magni Paolo , Porzano Thomas 
Published: November 2003

AbstractConcurrent Solvent Recondensation Large Sample Volume (CRS‐LV) splitless injection overcomes the limitation of the maximum sample volume to 1–2 μL valid for classical splitless injection. It is based on control of the evaporation rate in the vaporizing chamber, utilization of a strong pressure increase in the injector resulting from solvent evaporation, and greatly accelerated transfer of the sample vapors from the injector into the inlet of an uncoated precolumn by recondensation of the solvent. The sample vapors are transferred into the column as rapidly as they are formed in the injector (concurrent transfer). 20–50 μL of liquid sample is injected with liquid band formation. The sample liquid is received by a small packing of deactivated glass wool positioned slightly above the column entrance at the bottom of the vaporizing chamber. Solvent evaporation strongly increases the pressure in the injector (auto pressure surge), provided the septum purge outlet is closed and the accessible volumes around the vaporizing chamber are small, driving the first vapors into the precolumn. Transfer continues to be fast because of recondensation of the solvent, obtained by keeping the oven temperature below the pressure‐corrected solvent boiling point. The uncoated precolumn must have sufficient capacity to retain most of the sample as a liquid. The experimental data show virtually complete absence of discrimination of volatile or high boiling components as well as high reproducibility.