bluuebunny/crossref_metadata_2025_split huggingface dataset:
On‐site alginate gelation for enhanced cell proliferation and uniform distribution in porous scaffolds
Authors: Li Zhensheng , Gunn Jonathan , Chen Ming‐Hong , Cooper Ashleigh , Zhang Miqin 
Published: January 2008

AbstractHigh cell density and uniformity in a tissue‐engineered construct is essential to expedite the formation of a uniform extracellular matrix. In this study, we demonstrated an on‐site gelation approach to increase cellular population and uniformity through porous scaffolds using alginate as gelling material. The on‐site gelation was triggered during cell seeding and was shown to effectively restrain the cells in the porous scaffold during subsequent cell cultivation. The initial demonstration of the effectiveness of this system was made with chondrocyte cells, targeted at functional restoration of damaged or dysfunctional cartilage. By limiting cellular mobility, cell population increased by 89% after 7 days of cell culture in scaffolds encapsulating alginate gel as opposed to a 36% increase in scaffolds without gel. The cell distribution throughout the gelled scaffold was found to be more uniform than in the nongelled scaffold. SEM analysis revealed that the cells exhibited typical chondrocytic morphology. Improved cellular functionality was verified by low levels of collagen type I gene expression and steady gene activity levels of collagen type II over 3 weeks of cell cultivation. Alternatively, cells seeded in scaffolds with the conventional cell‐seeding method demonstrated increased levels of collagen type I gene expression, indicating the possibility of cell dedifferentiation over long‐term cell culture. Success with the chitosan–alginate scaffold model suggested that this flexible on‐site gelation method could be potentially applied to other cell and tissue types for enhanced tissue engineering development. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Corrosive effects of fluoride on titanium: Investigation by X‐ray photoelectron spectroscopy, atomic force microscopy, and human epithelial cell culturing
Authors: Stájer Anette , Ungvári Krisztina , Pelsőczi István K. , Polyánka Hilda , Oszkó Albert , Mihalik Erzsébet , Rakonczay Zoltán , Radnai Márta , Kemény Lajos , Fazekas András , Turzó Kinga 
Published: January 2008

AbstractHigh fluoride (F−) concentrations and acidic pH impair the corrosion resistance of titanium (Ti). Effects of F−‐containing caries‐preventive prophylactic rinses, and gels on Ti were investigated by X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Human epithelial cell attachment and proliferation were investigated by dimethylthiazol‐diphenyl tetrazolium bromide (MTT) and protein content assays. Aqueous 1% NaF solution (3800 ppm F−, pH 4.5) or high (12,500 ppm) F− content gel (pH 4.8) strongly corroded the surface and modified its composition. XPS revealed formation of a strongly bound F−‐containing complex (Na2TiF6). AFM indicated an increase in roughness (Ra) of the surfaces: 10‐fold for the NaF solution and smaller for the gel or a mouthwash (250 ppm F−, pH 4.4). MTT revealed that cell attachment was significantly increased by the gel, but was not disturbed by either the mouthwash or the NaF. Cell proliferation determined by MTT decreased significantly only for the NaF‐treated samples; protein content assay experiments showed no such effect. This study indicates that epithelial cell culturing results can depend on the method used, and the adverse effects of a high F− concentration and low pH should be considered when prophylactic gels are applied by patients with Ti implants or other dental devices. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Allocation of nonbirefringent wear debris: Darkfield illumination associated with PIXE microanalysis reveals cobalt deposition in mineralized bone matrix adjacent to CoCr implants
Authors: Busse B. , Hahn M. , Niecke M. , Jobke B. , Püschel K. , Delling G. , Katzer A. 
Published: January 2008

AbstractAbrasive joint replacement material that accumulates in the tissue induces reciprocal effects between prosthesis material and organism. Since the limitations of brightfield and polarized light microscopy for foreign body analysis are well known, a method was applied that ensures the detailed histological assessment of nonbirefringent particles in periprosthetic soft and hard tissue. Cemented and cementless interface regions of five selected autopsy hip implant cases (2 × Endo‐Modell Mark III, LINK, 1 × St. Georg Mark II, LINK, Germany; 2 × Spongiosa Metal II, ESKA, Germany) were viewed under darkfield illumination and subsequently analyzed with proton‐induced X‐ray emission (PIXE). Eight autopsy cases without implants served as controls. Using darkfield illumination technique, metallic particles became visible as luminous points under the microscope. The majority of particles in the samples from the cemented cases were degradation products of radiopaque bone cement. There was minimal evidence of metallic alloy particles in the soft tissues. However, a considerable quantity of heavy metal cobalt (Co) was found in the periprosthetic mineralized bone tissue, which was not observed in the controls. The periprosthetic concentration of cobalt ranged from 38 to 413 ppm. The findings demonstrate a correlation between cobalt concentration, time since implantation, and distance from the implant. Darkfield microscopy associated with PIXE enables a detailed histological assessment of metal particles in the tissue. In an effort to optimize biomechanics, implant design and implantation techniques, the contamination of soft and hard tissue with heavy metal degradation products deserves similar attention in terms of alloy assortment. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Cytocompatibility of aliphatic polyesters—In vitro study on fibroblasts and macrophages
Authors: Pamula Elzbieta , Dobrzynski Piotr , Szot Barbara , Kretek Magdalena , Krawciow Jolanta , Plytycz Barbara , Chadzinska Magdalena 
Published: January 2008

AbstractA resorbable copolymer of glycolide and L‐lactide (PGLA), a terpolymer of glycolide, L‐lactide, and ε‐caprolactone (PGLCL), and a copolymer of glycolide and ε‐caprolactone (PGCL) were synthesized by ring opening polymerization using zirconium acetylacetonate (Zr(acac)4) as an initiator. The structure and physicochemical surface properties of the materials were studied by NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, X‐ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. On the basis of contact angle measurements and the Owens‐Wendt approach, the surface free energy was calculated. The effect of polymeric films produced by solvent casting on morphology and activity of L929 fibroblasts, and two types of macrophages (macrophages from peritoneal exudates and RAW 264.7 monocytes/macrophages), was analyzed. It was found that viability, adhesion, and morphology of fibroblasts on PGLA were very similar to control glass. On PGLCL more adhering cells were round, while on PGCL only single, poorly spread cells were seen, and their viability was significantly reduced. This may suggest that the interaction of fibroblasts with PGCL was due to its hydrophobicity and a very low polarity. Adhesion and viability of RAW 264.7 cells was significantly enhanced on PGLA but reduced on both PGLCL and PGCL. The increased synthesis/release of chemoattractants and metalloproteinases‐2 and ‐9 was observed in the macrophages from peritoneal exudates cultured on PGLA and PGLCL. The viability of cells decreased in the following order: PGLA > PGLCL > PGCL. It is worth noting that glass transition temperature and susceptibility to mechanical deformation of the polymeric materials also decreased in the same order. It may imply that those physical parameters should be also considered as potential factors affecting cell behavior. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Effects of sterilization on poly(ethylene glycol) hydrogels
Authors: Kanjickal Deenu , Lopina Stephanie , Evancho‐Chapman M. Michelle , Schmidt Steven , Donovan Duane 
Published: January 2008

AbstractThe past few decades have witnessed a dramatic increase in the development of polymeric biomaterials. These biomaterials have to undergo a sterilization procedure before implantation. However, many sterilization procedures have been shown to profoundly affect polymer properties. Poly(ethylene glycol) hydrogels have gained increasing importance in the controlled delivery of therapeutics and in tissue engineering. We evaluated the effect of ethylene oxide (EtO), hydrogen peroxide (H2O2), and gamma sterilization of poly(ethylene glycol) hydrogels on properties relevant to controlled drug delivery and tissue engineering. We observed that the release of cyclosporine (CyA) (an immunosuppressive drug that is effective in combating tissue rejection following organ transplantation) was significantly affected by the type of sterilization. However, that was not the case with rhodamine B, a dye. Hence, the drug release characteristics were observed to be dependent not only on the sterilization procedure but also on the type of agent that needs to be delivered. In addition, differences in the swelling ratios for the sterilized and unsterilized hydrogels were statistically significant for 1:1 crosslinked hydrogels derived from the 8000 MW polymer. Significant differences were also observed for gamma sterilization for 1:1 crosslinked hydrogels derived from the 3350 MW polymer and also the 2:1 crosslinked hydrogels derived from the 8000 MW polymer. Atomic force microscopy (AFM) studies revealed that the roughness parameter for the unsterilized and EtO‐sterilized PEG hydrogels remained similar. However, a statistically significant reduction of the roughness parameter was observed for the H2O2 and gamma‐sterilized samples. Electron spin resonance (ESR) studies on the unsterilized and the sterilized samples revealed the presence of the peroxy and the triphenyl methyl carbon radical in the samples. The gamma and the H2O2‐sterilized samples were observed to have a much higher concentration of the radical pecies when compared with the EtO and the unsterilized samples. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Enhanced neurite alignment on micro‐patterned poly‐L‐lactic acid films
Authors: Li Jianming , McNally Helen , Shi Riyi 
Published: January 2008

AbstractThe ability of the damaged central nervous system and peripheral nervous system to properly recover hinges on the regenerative mechanisms and functional reconnection to appropriate targets. Successful pathfinding of axons is controlled by a complex interplay of diffusible or substrate‐bound biochemical and electrical cues. Physical guidance has also been shown to occur in vivo and in vitro, either via cell–cell or cell‐extracellular matrix mediated contact. In the current study, we probe the role of contact guidance in facilitating neural regeneration and pathfinding. Using soft lithographic techniques, we have created thin films of poly‐L‐lactic acid polymer (PLLA) possessing periodic features approaching the nanometer regime. Rat PC‐12 cells and chick sympathetic neurons were subsequently cultured onto these substrates and parameters, such as neurite emergence and orientation angle, neurite length, and neuronal architecture are characterized. Our results reveal that both PC‐12 and chick sympathetic neurites can be effectively guided by unidirectional grooves as small as 100 nm in height and 1 μm in width. Moreover, sympathetic cells produced neurites that were longer on patterned substrata than on controls. The development of novel degradable micro/nanopatterned substrates for cell study will permit more in‐depth analysis of contact mediated guidance mechanisms in addition to having applications in neural and tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Nanoporesize affects complement activation
Authors: Ferraz Natalia , Nilsson Bo , Hong Jaan , Karlsson Ott Marjam 
Published: January 2008

AbstractIn the present study, we have shown the vast importance of biomaterial nanotexture when evaluating inflammatory response. For the first time in an in vitro whole blood system, we have proven that a small increase in nanoporesize, specifically 180 nm (from 20 to 200 nm), has a huge effect on the complement system. The study was done using nanoporous aluminiumoxide, a material that previously has been evaluated for potential implant use, showing good biocompatibility. This material can easily be manufactured with different pore sizes making it an excellent candidate to govern specific protein and cellular events at the tissue‐material interface. We performed whole blood studies, looking at complement activation after blood contact with two pore size alumina membranes (pore diameters, 20 and 200 nm). The fluid phase was analyzed for complement soluble components, C3a and sC5b‐9. In addition, surface adsorbed proteins were eluted and dot blots were performed to detect IgG, IgM, C1q, and C3. All results point to the fact that 200 nm pore size membranes are more complement activating. Significantly, higher values of complement soluble components were found after whole blood contact with 200 nm alumina and all studied proteins adsorbed more readily to this membrane than to the 20 nm pore size membrane. We hypothesize that the difference in complement activation between our two test materials is caused by the type and the amount of adsorbed proteins, as well as their conformation and orientation. The different protein patterns created on the two alumina membranes are most likely a consequence of the material topography. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Wnt signaling acts and is regulated in a human osteoblast differentiation dependent manner
Authors: Eijken M. , Meijer I.M.J. , Westbroek I. , Koedam M. , Chiba H. , Uitterlinden A.G. , Pols H.A.P. , van Leeuwen J.P.T.M. 
Published: January 2008

AbstractThe Wnt signaling pathway is an important regulator of cellular differentiation in a variety of cell types including osteoblasts. In this study, we investigated the impact of Wnt signaling on the function of human osteoblasts in relation to the stage of differentiation. Differentiating osteoblasts were created upon glucocorticoid (GC) treatment, whereas nondifferentiating osteoblasts were created by excluding GCs from the culture medium. GC‐induced differentiation suppressed endogenous β‐catenin levels and transcriptional activity. During GC‐induced osteoblast differentiation, activation of Wnt signaling slightly decreased alkaline phosphatase activity, but strongly suppressed matrix mineralization. In addition, mRNA expression of several Wnt signaling related genes was strongly regulated during GC‐induced osteoblast differentiation, including frizzled homolog 8, dickkopf homolog 1, and secreted frizzled‐related protein 1. In contrast, in the absence of GC‐induced differentiation, Wnt signaling acted positively by stimulating basal alkaline phosphatase activity. Interestingly, pre‐stimulation of Wnt signaling in early osteoblasts enhanced their differentiation capacity later on during the GC‐induced differentiation process. In conclusion, we showed a differentiation‐dependent effect of Wnt signaling on osteoblasts. Wnt signaling stimulated early osteoblasts in their capacity to differentiate, whereas mature osteoblasts were strongly inhibited in their capacity to induce mineralization. Moreover, osteoblast differentiation suppressed endogenous Wnt signaling and changed the expression of multiple Wnt signaling related genes. J. Cell. Biochem. 104: 568–579, 2008. © 2008 Wiley‐Liss, Inc.
Metacognitive interpersonal therapy in a case of obsessive–compulsive and avoidant personality disorders
Authors: Fiore Donatella , Dimaggio Giancarlo , Nicoló Giuseppe , Semerari Antonio , Carcione Antonino 
Published: January 2008

AbstractMetacognitive interpersonal therapy (MIT) for personality disorders is aimed at both improving metacognition—the ability to understand mental states—and modulating problematic interpersonal representations while building new and adaptive ones. Attention to the therapeutic relationship is basic in MIT. Clinicians recognize any dysfunctional relationships with patients and work to achieve attunement to make the latter aware of their problematic interpersonal patterns. The authors illustrate here the case of a man suffering from obsessive–compulsive and avoidant personality disorders with dependent traits. He underwent combined individual and group therapies to (a) modulate his perfectionism, (b) prevent shifts towards avoiding responsibilities to protect himself from feared negative judgments, and (c) help him acknowledge suppressed desires. We show how treatment focused on the various dysfunctional personality aspects. © 2008 Wiley Periodicals, Inc. J Clin Psychol: In Session 64: 1–13, 2008.
Future trends of climatic belts and seasons in China
Authors: Jiang Yundi , Wang Shuyu , Yang Song , Dong Wenjie , Fu Congbin , Zhao Tianbao 
Published: January 2008

AbstractIn this study, the present and future climate under the Intergovernmental Panel on Climate Change (IPCC) A2 scenario of CO2 emission are simulated by using the Regional Integrated Environment Modeling System (RIEMS). The simulated climatic belts, climatic seasons, and Yellow River ice phenology in China are compared between the present climate during 1975–1984 and the future climate during 2035–2044. The long‐term trends of the regional climate are also estimated.Compared to 1975–1984, most of the climatic belts in China will shift northward in 2035–2044, by a maximum of 1.5–2° of latitude. The southern boundary of the Northern Sub‐tropical Belt (NSB) will shift northward significantly, in spite of the little change in its northern boundary. The entire Southern Sub‐tropical Belt (SSB) and the Middle Sub‐tropical Belt (MSB), as well as the northern boundary of the Warm Extra‐tropical Belt (WEB), will also shift northward by 1–2° of latitude. The starting dates of spring and summer will mostly advance, opposite to the delays in the starting dates of autumn and winter. As a whole, the summer in China will grow longer by 26.1 days, while spring, autumn, and winter will become shorter by 6.8, 7.9, and 11.4 days, respectively. In the upper reach of the Yellow River (URYR), the date for enduring sub‐zero temperatures will be delayed by 8 days and the date for enduring above‐zero temperatures will advance by 5 days. In the lower reach of the river, the date for enduring sub‐zero temperatures will be delayed by 4 days and the date for enduring above‐zero temperatures will advance by 4 days. Copyright © 2008 Royal Meteorological Society
Magnetic resonance image analysis of meniscal translation and tibio‐menisco‐femoral contact in deep knee flexion
Authors: Yao Jiang , Lancianese Sarah L. , Hovinga Kristen R. , Lee Jordan , Lerner Amy L. 
Published: January 2008

AbstractThe purpose of this study was to clarify meniscal displacement and cartilage–meniscus contact behavior in a full extension position and a deep knee flexion position. We also studied whether the meniscal translation pattern correlated with the tibiofemoral cartilage contact kinematics. Magnetic resonance (MR) images were acquired at both positions for 10 subjects using a conventional MR scanner. Subjects achieved a flexion angle averaging 139° ± 3°. Both medial and lateral menisci translated posteriorly on the tibial plateau during deep knee flexion. The posterior translation of the lateral meniscus (8.2 ± 3.2 mm) was greater than the medial (3.3 ± 1.5 mm). This difference was correlated with the difference in tibiofemoral contact kinematics between medial and lateral compartments. Contact areas in deep flexion were approximately 75% those at full extension. In addition, the percentage of area in contact with menisci increased significantly due to deep flexion. Our results related to meniscal translation and tibio‐menisco‐femoral contact in deep knee flexion, in combination with information about force and pressure in the knee, may lead to a better understanding of the mechanism of meniscal degeneration and osteoarthritis associated with prolonged kneeling and squatting. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:673–684, 2008
Availability of certain nutrients in cereals reconstituted with or without enzymes for chickens
Authors: Manwar Satish J , Mandal Asit B 
Published: January 2008

AbstractBACKGROUND: The presence of various anti‐nutritional factors, poor digestibility of the protein and carbohydrates greatly affect the utilisation of cereal grains in birds. Therefore, in the present investigation, efforts were made to augment the availability of certain nutrients of cereal grains through reconstitution with or without added enzymes.RESULTS: Reconstitution of grains with enzymes increased the apparent metabolisable energy‐nitrogen corrected (AMEn) values of pearl millet, sorghum, maize and wheat by 10.81, 7.39, 1.74 and 5.11% over untreated grains, while the corresponding increase for the grains reconstituted without enzymes was 8.28, 5.45, 1.95 and 0.06%, respectively. The reconstitution of cereal grains without added enzymes improved the in vitro pepsin pancreatin digestibility (IVPPD) of pearl millet, sorghum, maize and wheat by 19, 23, 20 and 11% over their respective untreated counterparts. Reconstitution with or without enzymes reduced the available carbohydrates and acid detergent fibre contents. The phytate contents were decreased significantly (P < 0.01) due to reconstitution with or without enzymes up to 48‐60% for all the grains.CONCLUSION: It may be inferred that the reconstitution of the grains caused significant reduction in anti‐nutritional factors of the grains, which was accompanied by significant improvement in nutrient availability. Reconstitution was found to be less expensive method of feed processing and can easily be adopted under field conditions. Addition of enzymes in the process of reconstitution provided additional advantage in nutrient availability for all the cereals except maize, and the improvement was much higher in wheat. Copyright © 2008 Society of Chemical Industry
Winter cover crops for local ecosystems: linking plant traits and ecosystem function
Authors: Wilke Brook J , Snapp Sieglinde S 
Published: January 2008

AbstractWinter cover crops are capable of supplying multiple economic and environmental benefits in temperate environments of North America, but the lack of adapted populations for specific environmental and agricultural contexts has resulted in cover crops that are unreliable and perform ecosystem functions unevenly. To maximize the benefits provided by winter cover crops, we argue for trait selection by crop scientists that is cognizant of desired ecosystem functions, with the goal of providing commercially available populations that have variable functions. We illustrate this approach through a case study of a promising winter annual legume cover crop, hairy vetch (Vicia villosa). Six key traits and associated functions are considered within specific agroecological contexts. We discuss tradeoffs that may occur among desired plant traits and illustrate how over‐selection for a particular trait could negatively affect performance and overall benefits from a cover crop. Intraspecific combinations of complementary cover crops are suggested as means to achieve multiple agroecosystem functions. Copyright © 2008 Society of Chemical Industry