bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioactive and biocompatible pieces of HA/sol‐gel glass mixtures obtained by the gel‐casting method
Authors: Padilla S. , Sánchez‐Salcedo S. , Vallet‐Regí M. 
Published: August 2005

AbstractHydroxyapatite (HA)/glass mixtures have shown a faster bioactive behaviour than HA itself. On the other hand, the gel‐casting method is a simple and reproducible colloidal method to produce ceramic pieces with complex shapes. In this work, pieces of HA/glass mixtures were prepared by the gel‐casting method. A study for obtaining concentrated slurries of these mixtures is reported; the bioactivity and biocompatibility of the obtained pieces have been studied also. The influence of pH, dispersant concentration, the content and milling of glass, and the way to prepare the suspensions were investigated. The lowest viscosity and better rheological properties were achieved with the lowest glass content, when the glass was added after the dispersion of the HA powder and when the glass was not milled after calcination. Fluid suspensions with a high solid content (50 vol.%) could be prepared and well‐shaped pieces were obtained from these slurries. These pieces showed in vitro bioactive behavior in simulated body fluid; additionally, the proliferation and spreading assays with osteoblastic cells (HOS) showed that the pieces are biocompatible. The results obtained indicate that the gel‐casting of HA/glass mixtures produces bioactive and biocompatible pieces with the required shapes. Therefore, these materials could be good candidates for clinical applications and scaffolds for tissue engineering. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Serum deprivation improves seeding and repopulation of acellular matrices with valvular interstitial cells
Authors: Cushing Melinda C. , Jaeggli Michael P. , Masters Kristyn S. , Leinwand Leslie A. , Anseth Kristi S. 
Published: August 2005

AbstractCell‐extracted valvular tissues (acellular scaffolds, or aScaffolds) offer unique advantages over synthetic polymers for cardiac valve engineering applications in that they retain extracellular matrix molecules to support cellular ingrowth. The extracellular matrix is important in directing many cellular pathways, such as adhesion, proliferation, migration, differentiation, and survival. However, repopulating this type of scaffold often requires high seeding densities or recurrent cell delivery. The optimization of valvular interstitial cell (VIC) seeding onto aScaffolds is reported herein. VICs (the most prevalent cell type in valve leaflets) have maximal growth in 15–20% serum concentrations on tissue‐culture polystyrene. Interestingly, after VIC seeding onto aScaffolds, a reduction of serum content, from 15% serum to 5% or less, was found to increase significantly the number of adherent cells, as well as induce transfer of VICs from a tissue‐culture polystyrene surface to the aScaffold. aScaffolds seeded and cultured with periods of reduced serum levels were shown to support and enhance VIC viability and attachment, as well as accelerate VIC migration into the aScaffold, leading to a uniformly repopulated valve leaflet construct after 4 weeks of static culture. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Development of multifunctional polymer–mineral composite materials for bone tissue engineering
Authors: Vlakh Evgenia G. , Panarin Evgeniy F. , Tennikova Tatiana B. , Suck Kirstin , Kasper Cornelia 
Published: August 2005

AbstractThe main goal of this article is the development of a novel approach to construct multifunctional composite scaffolds for bone tissue engineering. For this purpose, different kinds of mineral macroporous supports, water‐soluble aldehyde‐containing copolymers of N‐vinylpyrrolidone, as well as different nonspecific and biospecific ligands governing cell adhesion and growth have been used. The composite materials were tested initially for cytotoxicity in cell culture experiments using a model cell line. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Suppression of polyethylene particle–induced osteolysis by exogenous osteoprotegerin
Authors: von Knoch Fabian , Heckelei Anja , Wedemeyer Christian , Saxler Guido , Hilken Gero , Brankamp Jochen , Sterner Thomas , Landgraeber Stefan , Henschke Frank , Löer Franz , von Knoch Marius 
Published: August 2005

AbstractAlterations of the key regulators of osteoclastogenesis, receptor activator of NF‐kappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) have been implicated in wear particle–induced osteolysis, the most common cause for implant failure in total joint replacements. This study investigated the effect of exogenous OPG on ultra‐high‐molecular‐weight polyethylene (UHMWPE) particle–induced osteolysis. The murine calvarial osteolysis model was utilized in 28 C57BL/6J mice randomized to four groups. Group I underwent sham surgery only, group II received UHMWPE particles, and group III and IV particles and subcutaneous OPG starting from day 0 (group III) or day 5 (group IV) until sacrifice. After 2 weeks, calvaria were prepared for histology and histomorphometry. Bone resorption was measured within the midline suture using Giemsa staining and osteoclast numbers were determined using TRAP staining. UHMWPE particle implantation resulted in grossly pronounced osteoclastogenesis and bone resorption. Both immediate and delayed treatment with OPG counteracted these particle‐induced effects significantly, suppressing osteoclast formation and bone resorption (p < 0.001 and p < 0.001, respectively). In conclusion, exogenous OPG markedly suppressed UHMWPE particle–induced osteolysis in a murine calvarial model. This important finding underscores the crucial significance of the OPG‐RANKL‐RANK signaling in wear particle–induced osteolysis. Exogenous OPG may prove an effective treatment modality for wear debris‐mediated periprosthetic osteolysis after total joint arthroplasty. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Prolonged duration local anesthesia with lipid–protein–sugar particles containing bupivacaine and dexamethasone
Authors: Colombo Gaia , Padera Robert , Langer Robert , Kohane Daniel S. 
Published: August 2005

AbstractGlucocorticoids prolong block duration from polymeric microspheres containing bupivacaine, but not from unencapsulated drug. Here we investigate this effect applies to particles with much more rapid drug release and improved long‐term biocompatibility. Male Sprague‐Dawley rats were given sciatic nerve blocks with 75 mg of 3% or 60% (w/w) dipalmitoylphosphatidylcholine (DPPC) spray‐dried lipid–protein–sugar particles (LPSPs) containing 10% (w/w) bupivacaine and 0%, 0.05%, or 0.1% (w/w) dexamethasone. Sensory nerve block from bupivacaine‐containing 3% and 60% (w/w) DPPC particles without dexamethasone yielded blocks lasting 301 ± 56 and 321 ± 127 min, respectively. Addition of 0.05% (w/w) dexamethasone increased block durations to 610 ± 182 and 538 ± 222 min, respectively; increasing dexamethasone loading to 0.1% did not further increase duration. One day after injection, dexamethasone‐containing particles resulted in lower inflammation scores and capsule thickness than dexamethasone‐free particles, but the difference was gone by day 4. Excipient composition had prominent effects at all time points. For all groups, inflammation was largely resolved by 2 weeks after injection. Dexamethasone approximately doubled the duration of nerve block from bupivacaine‐loaded LPSPs, while maintaining excellent biocompatibility. Such formulations could be useful in clinical applications when nerve blockade is needed for 24 hours or less. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
A multiplex PCR method for the detection of all five individual genes of ica locus in Staphylococcus epidermidis. A survey on 400 clinical isolates from prosthesis‐associated infections
Authors: Arciola Carla Renata , Gamberini Simonetta , Campoccia Davide , Visai Livia , Speziale Pietro , Baldassarri Lucilla , Montanaro Lucio 
Published: August 2005

AbstractIn Staphylococcus epidermidis, ica locus encodes for the synthesis of a polysaccharide intercellular adhesin (slime or biofilm). A multiplex polymerase chain reaction (PCR) for the detection of the five individual genes of ica locus was developed, with the aim to probe the set of genes in a large collection of Staphylococcus epidermidis clinical isolates. Single representative fragments for icaR, icaA, icaD, icaB, and icaC genes were selected. Multiplex PCR was applied to two reference Staphylococcus epidermidis strains [the non–biofilm‐forming ATCC 12228 and the biofilm‐forming ATCC 35984 (RP62A)] and to 400 clinical isolates of Staphylococcus epidermidis from orthopedic prosthesis associated infections. The gene profile was compared with the phenotypic biofilm‐forming ability, evaluated by means of an optimized Congo red agar (CRA) plate test. Among the clinical isolates, 228 (57%) turned out completely ica positive and were biofilm producing. Among the 172 non–biofilm‐forming strains (43%), 164 (41%) were completely ica negative and 8 strains (2%) harbored all five ica genes. The ica locus thus proves to be a cluster of strictly linked genes, without any evidence of single gene deletion. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Defect‐induced fatigue microcrack formation in cement mantle
Authors: Qi Gang , Li Jihui , Mouchon W. Paul , Lewis Gladius 
Published: August 2005

AbstractAcoustic emission (AE) was used to monitor the progress of the fatigue damage process in the cement mantles of two cemented femur stem constructs that contained naturally occurring defects. After the fatigue tests, morphological features of the defects were investigated using an environmental scanning electron microscope. It showed that the regions with no visible defects were mainly microcrack free, whereas the defect regions were the main sources generating microcracks. Two types of microcracks were identified: type I and type II. Signal energies associated with type I microcracks were about an order of magnitude higher than that of type II. The microstructural investigations of the defects and the areas in the vicinity of the defects suggested their categorization into stable and unstable. The accumulative energy–time relationships revealed that stable and unstable microcrack curves had convex
, and concave
shapes, respectively. The progress of fatigue microcrack formation occurred over three distinct phases: initiation, transition, and stableness. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Evaluation of calcium titanate as apatite growth promoter
Authors: Coreño J. , Coreño O. 
Published: August 2005

AbstractCalcium titanate (CaTiO3, perovskite) has been used to determine its apatite nucleation ability and propose a possible nucleation initial step. Measurements of calcium leaching from the calcium titanate surface and phosphate adsorption experiments were carried out separately by using commercial calcium titanate suspensions at room temperature. Adsorption behaviour determined by ζ potential measurements shows that phosphate is strongly adsorbed on the calcium titanate surface. It was found that the higher the pH, the higher the Ca present on the calcium titanate surface, but phosphate adsorption followed this trend only up to pH 7.4. Results suggest that phosphate ions are not adsorbed only on Ca sites but also on TiO2 groups sites of the surface, formed after calcium leaching from the surface. When both ions are simultaneously added in a modified simulated body fluid containing calcium titanate, at 37°C, apatite growth occurs on its surface after 1 week of immersion. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Parathyroid hormone (PTH) and hematopoiesis: New support for some old observations
Authors: Whitfield James F. 
Published: August 2005

AbstractForty‐seven years ago, the parathyroid hormone (PTH) in one injection of Lilly's old bovine parathyroid extract, PTE, was found to greatly increase the 30‐day survival of heavily X‐irradiated rats when given from 18 h before to as long as 3 h after irradiation but no later. This was the first indication that PTH might stimulate hematopoiesis. Recent studies have confirmed the relation between PTH and hematopoiesis by showing that hPTH‐(1‐34)OH increases the size of the hematopoietic stem cell pool in mice. The peptide operates through a cyclic AMP‐mediated burst of Jagged 1 production in osteoblastic cells lining the stem cells' niches on trabecular bone surfaces. The osteoblastic cells' Jagged 1 increases the hematopoietic stem cell pool by activating Notch receptors on attached stem cells. PTH‐triggered cyclic AMP signals also directly stimulate the proliferation of the hematopoietic stem cells. However, the single PTH injection in the early experiments using PTE probably increased the survival of irradiated rats mainly by preventing the damaged hematopoietic progenitors from irreversibly initiating self‐destructive apoptogenesis during the first 5 h after irradiation. It has also been shown that several daily injections of hPTH‐(1‐34)OH enable lethally irradiated mice to survive by stimulating the growth of transplanted normal bone marrow cells. If the osteogenic PTHs currently entering or on the verge of entering the market for treating osteoporosis can also drive hematopoiesis in humans as well as rodents, they could be potent tools for reducing the damage inflicted on bone marrow by cytotoxic cancer chemotherapeutic drugs and ionizing radiation. © 2005 Wiley‐Liss, Inc.
Nuclear inositol lipid metabolism: More than just second messenger generation?
Authors: Martelli Alberto M. , Follo Matilde Yung , Evangelisti Camilla , Falà Federica , Fiume Roberta , Billi Anna Maria , Cocco Lucio 
Published: August 2005

AbstractA distinct polyphosphoinositide cycle is present in the nucleus, and growing evidence suggests its importance in DNA replication, gene transcription, and apoptosis. Even though it was initially thought that nuclear inositol lipids would function as a source for second messengers, recent findings strongly indicate that lipids present in the nucleus also fulfil other roles. The scope of this review is to highlight the most intriguing advances made in the field over the last few years, such as the possibility that nuclear phosphatidylinositol (4,5) bisphosphate is involved in maintaining chromatin in a transcriptionally active conformation, the new emerging roles for intranuclear phosphatidylinositol (3,4,5) trisphosphate and phosphoinositide 3‐kinase, and the evidence which suggests a tight relationship between a decreased level of nuclear phosphoinositide specific phospholipase C‐β1 and the evolution of myelodisplastic syndrome into acute myeloid leukemia. © 2005 Wiley‐Liss, Inc.
Induction of osteogenic differentiation of human mesenchymal stem cells by histone deacetylase inhibitors
Authors: Cho Hyun Hwa , Park Hyung Taek , Kim Yeon Jeong , Bae Yong Chan , Suh Kuen Taek , Jung Jin Sup 
Published: August 2005

AbstractValproic acid (VPA) has been used as an anticonvulsant agent for the treatment of epilepsy, as well as a mood stabilizer for the treatment of bipolar disorder, for several decades. The mechanism of action for these effects remains to be elucidated and is most likely multifactorial. Recently, VPA has been reported to inhibit histone deacetylase (HDAC) and HDAC has been reported to play roles in differentiation of mammalian cells. In this study, the effects of HDAC inhibitors on differentiation and proliferation of human adipose tissue‐derived stromal cells (hADSC) and bone marrow stromal cells (hBMSC) were determined. VPA increased osteogenic differentiation in a dose dependent manner. The pretreatment of VPA before induction of differentiation also showed stimulatory effects on osteogenic differentiation of hMSC. Trichostatin A (TSA), another HDAC inhibitor, also increased osteogenic differentiation, whereas valpromide (VPM), a structural analog of VPA which does not possess HDAC inhibitory effects, did not show any effect on osteogenic differentiation on hADSC. RT‐PCR and Real‐time PCR analysis revealed that VPA treatment increased osterix, osteopontin, BMP‐2, and Runx2 expression. The addition of noggin inhibited VPA‐induced potentiation of osteogenic differentiation. VPA inhibited proliferation of hADSC and hBMSC. Our results suggest that VPA enhance osteogenic differentiation, probably due to inhibition of HDAC, and could be useful for in vivo bone engineering using hMSC. © 2005 Wiley‐Liss, Inc.
An augmented effective core potential basis set for the calculation of molecular polarizabilities
Authors: Labello Nicholas P. , Ferreira Antonio M. , Kurtz Henry A. 
Published: August 2005

AbstractCalculations of molecular polarizabilities require basis sets capable of accurately describing the responses of the electrons to an external perturbation. Unfortunately, basis sets that yield suitable quantitative results have traditionally been all‐electron sets with large numbers of primitives, making their use computationally intractable even for moderately sized systems. We present a systematic augmentation of the effective core potential basis set of Stevens et al. [J Chem Phys 81, 12 (1984), Can J Chem 70, 612 (1992)] for 39 main group elements based on the procedure used to construct diffuse and polarization functions in the well‐known Sadlej basis sets [Collec Czech Chem Comm 53, 1995 (1988)]. Representative calculations have been performed and we have shown that results to within 1% of all‐electron calculations using the Sadlej basis set can be obtained for <1–35% of the computational cost using this new basis set. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1464–1471, 2005
Nordhaus–Gaddum‐type Theorems for decompositions into many parts
Authors: Füredi Zoltan , Kostochka Alexandr V. , Škrekovski Riste , Stiebitz Michael , West Douglas B. 
Published: August 2005

AbstractA k‐decomposition (G1,…,Gk) of a graph G is a partition of its edge set to form k spanning subgraphs G1,…,Gk. The classical theorem of Nordhaus and Gaddum bounds χ(G1) + χ(G2) and χ(G1)χ(G2) over all 2‐decompositions of Kn. For a graph parameter p, let p(k;G) denote the maximum of $\sum _{i=1}^k p(G_i)$ over all k‐decompositions of the graph G. The clique number ω, chromatic number χ, list chromatic number χℓ, and Szekeres–Wilf number σ satisfy ω(2;Kn) = χ(2;Kn) = χℓ(2;Kn) = σ(2;Kn) =  n + 1. We obtain lower and upper bounds for ω(k;Kn), χ(k;Kn), χℓ(k;Kn), and σ(k;Kn). The last three behave differently for large k. We also obtain lower and upper bounds for the maximum of χ(k;G) over all graphs embedded on a given surface. © 2005 Wiley Periodicals, Inc. J Graph Theory
Cycle and circle tests of balance in gain graphs: Forbidden minors and their groups
Authors: Rybnikov Konstantin , Zaslavsky Thomas 
Published: August 2005

AbstractWe examine two criteria for balance of a gain graph, one based on binary cycles and one on circles. The graphs for which each criterion is valid depend on the set of allowed gain groups. The binary cycle test is invalid, except for forests, if any possible gain group has an element of odd order. Assuming all groups are allowed, or all abelian groups, or merely the cyclic group of order 3, we characterize, both constructively and by forbidden minors, the graphs for which the circle test is valid. It turns out that these three classes of groups have the same set of forbidden minors. The exact reason for the importance of the ternary cyclic group is not clear. © 2005 Wiley Periodicals, Inc. J Graph Theory
The benefit–incidence of public spending: the Caribbean experience
Authors: Gafar John 
Published: August 2005

AbstractThis paper shows that public spending on basic services, to wit, primary and secondary education and basic health care benefit the poor; while the non‐poor are the principal beneficiaries of tertiary and education subsidies and hospital spending. The evidence also shows that expenditures on infrastructure spending in the Caribbean benefit the non‐poor disproportionately more than the poor. Copyright © 2005 John Wiley & Sons, Ltd.
Revisiting privatization in the context of poverty alleviation: the case of Sudan
Authors: Dagdeviren Hulya 
Published: August 2005

AbstractPrivatization programmes in the developing world have often been assessed on the grounds of efficiency. In recent years a more critical literature with a focus on the distributional and poverty impact of privatization has emerged. This article contributes to that literature in two ways. First, it presents a broad framework of empirical analysis of the relationship between privatization and poverty. Second, it applies this framework to the case of Sudan in as much as the existing data and information permit. The results do not lend much support for the arguments that privatization contributes to the efforts of poverty alleviation through various channels such as efficiency, employment creation and revenue generation for government. Copyright © 2005 John Wiley & Sons, Ltd.
Some thoughts on the numerical modelling of electromagnetic processes
Authors: Hammond P. 
Published: August 2005

AbstractThe use of models in giving meaning to sense data is described. It is shown that models are essential to human understanding, but that there are no uniquely ‘best’ models. This leads to the discussion of the design of suitable models for engineering use. The role of physical and mathematical models is mentioned, and attention is drawn to geometrical and physical features. It is stated that numerical methods have overriding advantages, one of which is the possibility of numerical experimentation. The modelling of vector fields is discussed and attention is drawn to the ideas of differential geometry which attach the vector field to the space in which it acts. It is shown that variational methods, together with numerical experiments, can be used to derive invariant parameters which give both global and local information about electromagnetic systems in a particularly economical method of computation.
The modelling of multiaxial discontinuities in quasi‐planar structures with the modified TLM method
Authors: Saguet Pierre , Hoefer Wolfgang J. R. 
Published: August 2005

AbstractThe principal features of the modified TLM method such as the asymmetrical condensed node, graded mesh and dispersion characteristics, are briefly presented. Its general application to multiaxial discontinuities in quasi‐planar structures is described, and the modelling of bilateral finline T‐junctions is demonstrated in particular.
Characterization of wire‐grids for filters in circular waveguides at millimetre wavelengths
Authors: Landrac Gabrielle , Clequin René , Gelin Philippe 
Published: August 2005

AbstractIn order to develop a new kind of filter that makes a compromise between quasi‐optical and more traditional bandpass filtering techniques at millimetre wavelengths, a theoretical modelling of grids in oversize and monomodal waveguides is performed using a variational method.
A comparison between the time‐domain and the frequency‐domain diakoptic methods of solving field problems by transmission‐line modelling
Authors: Naylor Phillip , Christopoulos Christos 
Published: August 2005

AbstractThe nature and significance of time‐domain approximations needed for a diakoptic solution using transmission‐line modelling (TLM) are examined. Truncation, filtering and repeated convolution of time responses result in severe restrictions in the accuracy of time‐domain diakoptics. The frequency‐domain diakoptic method has several advantages, including speed and simplicity, and warrants further study.