bluuebunny/crossref_metadata_2025 huggingface dataset:
Building Niobate Nanoparticles with Hexaniobate Lindqvist Ions
Authors: Tong Hua , Ye Jinhua
Published: February 2010

We present a general method to fabricate niobate nanoparticles (NPs) by using hexaniobate Lindqvist ions as niobium source. First, soft‐chemical synthesis was adopted to prepare amorphous compound NPs, which subsequently served as parent bodies, affording not only nanoscale size but also optimal compositions and elements for the final annealed nanocrystalline niobates. By this method, a series of nanocrystalline niobates, including MNbO4 (M = In, Ga, Fe), MNb2O6 (M = Ba, Sr, Ni, Cd, Pb), MxFe1–xNbO4 (M = In, Ga), MxNi1–xNb2O6 (M = Ba, Sr), and (AgNb)1–x(SrTi)xO3, were successfully prepared. Experimental results presented herein show that the compositions and components of niobate NPs can be adjusted as desired, markedly influencing the crystal phase, energy band structure, and photocatalytic performance of the niobate NPs.
Oxidation of Biofuels: Fuel Diversity and Effectiveness of Fuel Oxidation through Multiple Enzyme Cascades
Authors: Sokic‐Lazic Daria , Arechederra Robert L. , Treu Becky L. , Minteer Shelley D.
Published: February 2010

Enzymatic biofuel cells have employed a variety of fuels, including: glucose, fructose, methanol, ethanol, glycerol, lactate, pyruvate and ethylene glycol. This review describes the wealth of fuel diversity in enzymatic biofuel cells, along with the use of multi‐enzyme cascades for deep or complete oxidation of biofuels at the anode of enzymatic biofuel cells. Deep or complete oxidation is a relatively new research area for enzymatic biofuel cells, but it is necessary to increase energy density and minimize product inhibition effects.
Electric Power Generation from Municipal, Food, and Animal Wastewaters Using Microbial Fuel Cells
Authors: Fornero Jeffrey J. , Rosenbaum Miriam , Angenent Largus T.
Published: February 2010

Here, we explore if microbial fuel cell (MFC) technology can replace activated sludge processes for secondary wastewater treatment. We will discuss the present limitations and problems of electric current generation when a complex wastewater is treated with a diverse and undefined community of microbes in large‐scale systems. These challenges include low coulombic efficiencies, slow kinetic rates, and nonlinear power density increases during scale‐up efforts. Finally, we developed a prediction of the main economic gain from treating wastewater with microbial fuel cells. We conclude that electricity generation will not justify MFC operation, but that BOD removal with this more sustainable technology is attractive.
Engineered Pyranose 2‐Oxidase: Efficiently Turning Sugars into Electrical Energy
Authors: Spadiut Oliver , Brugger Dagmar , Coman Vasile , Haltrich Dietmar , Gorton Lo
Published: February 2010

Due to the recent interest in enzymatic biofuel cells (BFCs), sugar oxidizing enzymes other than the commonly used glucose oxidase are gaining more importance as possible bioelements of implantable microscale‐devices, which can, for example, be used in biosensors and pacemakers. In this study we used rational and semi‐rational protein design to improve the catalytic activity of the enzyme pyranose 2‐oxidase (P2Ox) with its alternative soluble electron acceptors 1,4‐benzoquinone and ferricenium ion, which can serve as electron mediators, to possibly boost the power output of enzymatic BFCs. Using a screening assay based on 96‐well plates, we identified the variant H450G, which showed lower KM and higher kcat values for both 1,4‐benzoquinone and ferricenium ion compared to the wild‐type enzyme, when either D‐glucose or D‐galactose were used as saturating electron donors. Besides this variant, we analyzed the variants V546C and T169G/V546C for their possible application in enzymatic BFCs. The results obtained in homogeneous solution were compared with those obtained when P2Ox was immobilized on the surface of graphite electrodes and either “wired” to an osmium redox polymer or using soluble 1,4‐benzoquinone as mediator. According to the spectrophotometrically determined kinetic constants, the possible energy output, measured in flow injection analysis experiments with these variants, increased up to 4‐fold compared to systems employing the wild‐type enzyme.
Protein Engineering – An Option for Enzymatic Biofuel Cell Design
Authors: Güven Güray , Prodanovic Radivoje , Schwaneberg Ulrich
Published: February 2010

This review summarizes and discusses from a protein engineering point of view strategies to improve performances of biocatalysts in enzymatic biofuel cells. Emphasis will be given on biocatalysts employed in biofuel cells and protein engineering principles for achieving an efficient electrical communication between electrode and biocatalyst(s). Biocatalyst engineering by Rational Design and Directed Evolution offers opportunities to redesign and to improve biocatalysts for biofuel cell applications instead of accepting insufficient biocatalyst properties as unalterable limitations in the development of biofuel cells.
Grafted 2‐chloroethylphosphonic acid on inorganic supports used as flame retardant for unsaturated polyester resins
Authors: Ilia Gheorghe , Drehe Madalina
Published: February 2010

Flame retardants (FRs) are used for in protection against fire. Organic–inorganic hybrids could become one of the most promising FR solution in the future. In this paper, the synthesis, the characterization and the use as FRs and filler of grafted titania and alumina with 2‐chloroethylphosphonic acid are presented. These hybrids contain 3.8–3.24% P and have good flame retardance when they are incorporated into unsaturated polyester resins. Alumina treated with 2‐chloroethylphosphonic acid performed better than titania. The advantage of this approach is the use of these hybrid materials as filler and FR, in the same time, and the increase in flame retardancy by synergistic effect between alumina phosphorus and chlorine, for unsaturated polyester resins. Copyright © 2010 John Wiley & Sons, Ltd.
Radiation and magnetic field effects on the unsteady mixed convection flow of a second grade fluid over a vertical stretching sheet
Authors: Hayat T. , Qasim M.
Published: February 2010

This present analysis discusses the mixed convection boundary layer flow of a magnetohydrodynamic second grade fluid over an unsteady permeable stretching sheet. The time‐dependent stretching velocity and the surface temperature are chosen. Series solutions of the governing boundary value problems are obtained by employing homotopy analysis method. Convergence of the obtained solution is explicitly discussed. The dependence of velocity and temperature profiles on the various quantities is shown and discussed by plotting graphs. Skin friction coefficient and the local Nusselt number tabulated and analyzed. Copyright © 2010 John Wiley & Sons, Ltd.
Pattern of δ13Ccarb and implications for geological events during the Permian‐Triassic transition in South China
Authors: Cao C. Q. , Yang Y. C. , Shen S. Z. , Wang W. , Zheng Q. F. , Summons R. E.
Published: February 2010

Data from five marine sections across the Permian‐Triassic boundary in southern China reveal a pattern of 13C‐depleted carbonate (δ13Ccarb) in different facies spanning carbonate platform to lower slope. A gradual decrease of δ13Ccarb is evident in all sections and matched by an opposing change in 87Sr/86Sr from the Late Permian to the Induan (Early Triassic). These complementary trends in strontium and carbon isotope data imply an extended period of enhanced continental uplift and weathering of silicates and organic matter across the Permian‐Triassic event boundary (PTEB). A pronounced sharp drop of δ13Ccarb at the PTEB is most recognizable in the upper ramp environment of Meishan, occurs weakly in shallow water environments and cannot be discerned in the deepest water setting. We propose that this pattern reflects an enhancement of stratified‐ocean conditions in the immediate aftermath of the latest Permian transgression. The sharp drop in δ13Ccarb at the PTEB in the platform ramp environments likely resulted from the depth‐selective calcification of 13C‐depleted dissolved inorganic carbon (DIC) formed by respiration of organic matter including, perhaps, methane. Indeed, massive volcanism at the PTEB would have enhanced eutrophication and stratification thereby slowing the mixing of 13C‐depleted DIC into deeper‐water environments. Copyright © 2010 John Wiley & Sons, Ltd.
No excess risk of follicular lymphoma in kidney transplant and HIV‐related immunodeficiency
Authors: Vajdic Claire M. , van Leeuwen Marina T. , Turner Jennifer J. , McDonald Ann M. , Webster Angela C. , McDonald Stephen P. , Chapman Jeremy R. , Kaldor John M. , Grulich Andrew E.
Published: February 2010

Subtype‐specific incidence patterns in populations at high risk of lymphoma offer insight into lymphomagenesis. The incidence profiles for the 2 most common non‐Hodgkin lymphoma subtypes were compared for 2 immunodeficient populations, adults receiving a kidney transplant 1982–2003 (n = 7,730) or diagnosed with human immunodeficiency virus (HIV) infection 1982–2004 (n = 17,175). National, population–based registries were linked and standardized incidence ratios (SIRs) were computed for each cohort and lymphoma subtype. Risk of diffuse large B‐cell lymphoma was significantly increased after transplantation (SIR 17.83, 95% CI: 13.61–22.95) and after HIV infection (SIR 58.81, 95% CI: 52.59–65.56). Rates of follicular lymphoma (FL) were neither significantly increased nor decreased in transplant recipients (SIR 0.82, 95% CI: 0.10–2.96) and in people with HIV (SIR 1.25, 95% CI: 0.41–2.91). The findings argue against an infectious or other immunodeficiency‐related etiology for FL and clearly differentiate it from diffuse large B‐cell lymphoma.
Gastric cancer occurrence in preneoplastic lesions: A long‐term follow‐up in a high‐risk area in Spain
Authors: González Carlos A. , Pardo Maria Luisa , Ruiz Liso Juan Maria , Alonso Pablo , Bonet Catalina , Garcia Raul M. , Sala Núria , Capella Gabriel , Sanz‐Anquela José Miguel
Published: February 2010

There are no established criteria to classify patients into high or low risk of progressing to gastric cancer (GC). The aim of the study was to identify predictors of GC occurrence among patients with gastric preneoplastic lesions. A prospective and retrospective follow‐up study was carried out in a province in Spain with one of the highest risk of GC. The study included 478 patients who underwent gastric biopsy in 1988–1994 with diagnoses of normal mucosa, nonatrophic gastritis (NAG), non‐metaplastic multifocal atrophic gastritis (MAG) and complete or incomplete intestinal metaplasia (IM) and who accepted to undergo a new biopsy during 2005–2007 or had an event during follow up. Inter‐ and intra‐observer variability of histological diagnosis was assessed. Analysis was done using Cox proportional hazards risk (HR) models. The mean age of the patients was 50 years, 47% were males and the mean follow‐up time was 12.8 years. During follow‐up, 23 GC (4.8%) were diagnosed (21 adenocarcinomas and 2 lymphomas) with an incidence of 3.77 per 1,000 person per year. The incidence rate of GC for those with incomplete IM was 16.5 per 1,000 person years. Out the 21 adenocarcinomas, 16 had an incomplete IM in the baseline diagnosis. Incomplete IM (HR 11.3; 95% CI 3.8–33.9) and a family history of GC (HR 6.1; 95% CI 1.7–22.4) were the strongest risk factors for gastric adenocarcinoma. Subtyping of IM and family history of GC may be useful for the identification of high‐risk patients who need more intensive surveillance.
Cancer antineovascular therapy with liposome drug delivery systems targeted to BiP/GRP78
Authors: Katanasaka Yasufumi , Ishii Takayuki , Asai Tomohiro , Naitou Hirotaka , Maeda Noriyuki , Koizumi Fumiaki , Miyagawa Shinichi , Ohashi Norio , Oku Naoto
Published: February 2010

Angiogenesis is crucial for tumor growth and hematogenous metastasis. Specifically expressed and functional protein molecules in angiogenic endothelial cells, especially on the plasma membrane, may be molecular targets for antiangiogenic drugs and drug delivery systems (DDS) in cancer therapy. To discover such target molecules, we performed subcellular proteome analysis of human umbilical vein endothelial cells (HUVECs) treated with or without vascular endothelial growth factor (VEGF) using 2‐dimensional difference in‐gel electrophoresis (2D‐DIGE) and matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometry (MALDI‐TOF/TOF‐MS). Among the identified proteins, BiP/GRP78, a molecular chaperone, was highly expressed in the membrane/organelle fraction of HUVECs after VEGF treatment. The involvement of BiP in VEGF‐induced angiogenesis was examined by RNA interference. BiP knockdown significantly suppressed VEGF‐induced endothelial cell proliferation and VEGF‐induced phosphorylation of extracellular‐regulated kinase 1/2, phospholipase C‐γ, and VEGF receptor‐2 in HUVECs. Cell surface biotinylation analysis revealed that the cell surface expression of BiP was elevated in VEGF‐activated HUVECs. Aiming to apply BiP to a target molecule in liposomal DDS, we developed liposomes modified with the WIFPWIQL peptide, which has been shown to bind to BiP, and investigated its potential for cancer therapy. The WIFPWIQL‐modified liposomes (WIFPWIQL liposomes) were significantly taken up by VEGF‐activated HUVECs as compared to peptide‐unmodified liposomes. WIFPWIQL liposomes appeared to accumulate in tumor endothelial cells in vivo. WIFPWIQL liposomes containing doxorubicin significantly suppressed tumor growth and prolonged the survival of colon26 NL‐17 carcinoma cell‐bearing mice. In summary, BiP may regulate VEGF‐induced endothelial cell proliferation through VEGFR‐2‐mediated signaling and be an effective target molecule for cancer antineovascular therapy.
Keratin 6 expression correlates to areas of squamous differentiation in multiple independent isolates of As+3‐induced bladder cancer
Authors: Cao Ling , Zhou Xu Dong , Sens Mary Ann , Garrett Scott H. , Zheng Yun , Dunlevy Jane R. , Sens Donald A. , Somji Seema
Published: February 2010

This laboratory has shown that arsenite (As+3) exposure can cause the malignant transformation of the UROtsa human urothelial cell line. This single isolate formed subcutaneous tumors with a histology similar to human urothelial cell carcinoma. The tumors also displayed areas of squamous differentiation of the urothelial cells, an infrequent but known component of human bladder cancer. In the present study, five additional independent isolates of As+3‐transformed urothelial cells were isolated and each was shown to produce subcutaneous urothelial cell tumors with a characteristic histology very similar to those described in the initial report. That there were underlying phenotypic differences in the six independent isolates was demonstrated when they were assessed for their ability to form tumors within the peritoneal cavity. It was shown that two isolates could form hundreds of small peritoneal tumor nodules, one isolate a moderate number of tumor nodules, and three isolates no or only one tumor nodule. The peritoneal tumors were also characterized for their degree of squamous differentiation of the urothelial cells and, while areas of squamous differentiation could be found, such differentiation was substantially reduced compared to subcutaneous tumors. Immunostaining for keratin 6 was tested as a potential marker for malignant urothelial cells that had undergone squamous differentiation. Keratin 6 was shown to consistently stain only cells having some evidence of squamous differentiation. Keratin 16 was shown to follow the staining pattern of keratin 6. The isolates and tumor heterotransplants were all examined for keratin 6, 16 and 17 mRNA and protein expression. Copyright © 2010 John Wiley & Sons, Ltd.
Haemo‐ and cytocompatibility of bioresorbable homo‐ and copolymers prepared from 1,3‐trimethylene carbonate, lactides, and ϵ‐caprolactone
Authors: Yang Jian , Liu Feng , Tu Song , Chen Yuanwei , Luo Xianglin , Lu Zhiqian , Wei Jia , Li Suming
Published: February 2010

A series of bioresorbable polymers were prepared by ring‐opening polymerization of L‐lactide (LLA), DL‐lactide (DLLA), ϵ‐caprolactone (CL) and 1,3‐trimethylene carbonate (TMC), using low toxic zinc lactate as catalyst. The various PLLA, PTMC, PCL homopolymers, and PLLA‐TMC, PDLLA‐TMC, PCL‐TMC copolymers with 50/50 molar ratios were characterized by using analytical techniques such as proton nuclear magnetic resonance, gel permeation chromatography, tensiometer, and differential scanning calorimetry. The haemo‐ and cyto‐compatibility were investigated in order to evaluate the potential of the polymers as coating material in drug eluting stents. Haemolysis tests show that all the homo‐ and copolymers present very low haemolytic ratios, indicating good haemolytic properties. Adhesion and activation of platelets were observed on the surface of PLLA, PCL, PLLA‐TMC, and PDLLA‐TMC films, while less platelets and lower activation were found on PTMC. The most interesting results were obtained with PCL‐TMC which exhibited the lowest degree of activation with few adhered platelets, in agreement with its outstanding anticoagulant properties. Both indirect and direct cytocompatibility studies were performed on the polymers. The relative growth ratio data obtained from the liquid extracts during the 6‐day cell culture period indicate that all the polymers present very low cytotoxicity. Microscopic observations demonstrate adhesion, spreading and proliferation of human umbilical vein endothelial cells ECV304. Therefore, it is concluded that these bioresorbable polymers, in particular PCL‐TMC, are promising candidate materials as drug loading coating material in drug eluting stents. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Characterization of cyclic acetal hydroxyapatite nanocomposites for craniofacial tissue engineering
Authors: Patel Minal , Patel Ketan J. , Caccamese John F. , Coletti Domenick P. , Sauk John J. , Fisher John P.
Published: February 2010

Cyclic acetal hydrogels are a novel group of biomaterials which may facilitate osteogenic differentiation of encapsulated bone marrow stromal cells (BMSCs) because of their neutral degradation products. Here, we have incorporated hydroxyapatite nanoparticles within cyclic acetal hydrogels to create cyclic acetal nanocomposites for craniofacial tissue engineering applications. We hypothesized that inclusion of nanosized hydroxyapatite particles within cyclic acetal hydrogels would upregulate osteogenic signal expression of encapsulated BMSCs, due to enhanced cell adhesion, and therefore promote osteodifferentiation. Experimental nanocomposite groups consisted of lower (5 ng/mL) and higher (50 ng/mL) concentrations of nanoparticles. The nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy. Swelling parameters of hydrogels in the presence of nanoparticles was studied. Osteoblastic differentiation was characterized by alkaline phosphatase (ALP) and osteocalcin (OC) expression, whereas endogenous osteogenic signal expression was characterized by morphogenetic protein‐2 (BMP‐2) expression. Finally, immunohistochemistry was performed to detect the presence of OC at the protein level. Results indicated that hydroxyapatite nanoparticles were uniformly distributed throughout the hydrogels and did not affect material properties of the gels. Viability of cells was not affected by nanoparticle concentration, and BMP‐2 and OC mRNA expression was enhanced in the presence of nanoparticles. However, a difference in BMP‐2, ALP, and OC mRNA expression was not noted between the lower and higher concentrations of nanoparticles. This work demonstrates that inclusion of hydroxyapatite nanoparticles within a cyclic acetal nanocomposite hydrogel may enhance BMSC differentiation by promoting endogenous osteogenic signal expression. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Effect of chromium and cobalt ions on the expression of antioxidant enzymes in human U937 macrophage‐like cells
Authors: Tkaczyk Cathy , Huk Olga L. , Mwale Fackson , Antoniou John , Zukor David J. , Petit Alain , Tabrizian Maryam
Published: February 2010

The main concern associated with metal‐on‐metal (MM) hip prosthesis is the presence of metal ions, mainly chromium (Cr) and cobalt (Co), which are found both systemically and locally in the organism of patients. Previous studies revealed that Cr(III) and Co(II) ions could induce damages to proteins in macrophage‐like cells in vitro, probably through the formation of reactive oxygen species (ROS). We then hypothesized that these ions can modify the expression of antioxidant enzymes in these cells. Results showed that Cr(VI) induced the protein expression of Mn‐superoxide dismutase, Cu/Zn‐superoxide dismutase, catalase, glutathione peroxidase, and heme oxygenase‐1 (HO‐1) but had no effect of the expression of their mRNA. Cr(III) have no effect on the expression of all these antioxidant enzymes. Co(II) induced the expression of both protein and mRNA of HO‐1 only. In conclusion, results showed that Cr(VI), Cr(III), and Co(II) had differential effects on the expression of antioxidant enzymes in macrophage‐like cells in vitro. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Quantitative analysis of adhesive resin in the hybrid layer using Raman spectroscopy
Authors: Zou Yuan , Armstrong Steven R. , Jessop Julie L. P.
Published: February 2010

The objective was to determine absolute molar concentration of adhesive resin components in the hybrid layer by establishing methods based on Raman spectroscopy fundamentals. The hybrid layer was treated as a three‐component system consisting of collagen and an adhesive resin containing two monomers. Adhesive standard specimens and Raman peak area ratios obtained with a 785 nm excitation wavelength were used to construct separate calibration curves for comonomer relative molar concentration and Bis‐GMA absolute molar concentration. As collagen and water had no measurable peaks in the fingerprint region, a dilution coefficient Kj was defined to describe their impact on Raman peak area and to calculate HEMA absolute molar concentration. Methodology was validated using an analogous system containing acetone/ethanol/water. The absolute molar concentration of Bis‐GMA and HEMA decreased 87% and 83%, respectively, from the top quarter to the middle of the hybrid layer. Additionally, less Bis‐GMA penetrated the hybrid layer than HEMA, as indicated by the ∼20% decrease in comonomer molar concentration ratio between the adhesive resin layer and the top half of the hybrid layer. Lack of complete monomer infiltration will further challenge dentin‐adhesive bond longevity. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Collagen type I hydrogel allows migration, proliferation, and osteogenic differentiation of rat bone marrow stromal cells
Authors: Hesse Eric , Hefferan Theresa E. , Tarara James E. , Haasper Carl , Meller Rupert , Krettek Christian , Lu Lichun , Yaszemski Michael J.
Published: February 2010

Hydrogels are potentially useful for many purposes in regenerative medicine including drug and growth factor delivery, as single scaffold for bone repair or as a filler of pores of another biomaterial in which host mesenchymal progenitor cells can migrate in and differentiate into matrix‐producing osteoblasts. Collagen type I is of special interest as it is a very important and abundant natural matrix component. The purpose of this study was to investigate whether rat bone marrow stromal cells (rBMSCs) are able to adhere to, to survive, to proliferate and to migrate in collagen type I hydrogels and whether they can adopt an osteoblastic fate. rBMSCs were obtained from rat femora and plated on collagen type I hydrogels. Before harvest by day 7, 14, and 21, hydrogels were fluorescently labeled, cryo‐cut and analyzed by fluorescent‐based and laser scanning confocal microscopy to determine cell proliferation, migration, and viability. Osteogenic differentiation was determined by alkaline phosphatase activity. Collagen type I hydrogels allowed the attachment of rBMSCs to the hydrogel, their proliferation, and migration towards the inner part of the gel. rBMSCs started to differentiate into osteoblasts as determined by an increase in alkaline phosphatase activity after two weeks in culture. This study therefore suggests that collagen type I hydrogels could be useful for musculoskeletal regenerative therapies. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res 2010
The impact of hyaluronic acid oligomer content on physical, mechanical, and biologic properties of divinyl sulfone‐crosslinked hyaluronic acid hydrogels
Authors: Ibrahim Samir , Kang Qian K. , Ramamurthi Anand
Published: February 2010

In recent studies, we showed that exogenous hyaluronic acid oligomers (HA‐o) stimulate functional endothelialization, though native long‐chain HA is more bioinert and possibly more biocompatible. Thus, in this study, hydrogels containing high molecular weight (HMW) HA (1 × 106 Da) and HA‐o mixtures (HA‐o: 0.75–10 kDa) were created by crosslinking with divinyl sulfone (DVS). The incorporation of HA‐o was found to compromise the physical and mechanical properties of the gels (rheology, apparent crosslinking density, swelling ratio, degradation) and to very mildly enhance inflammatory cell recruitment in vivo; increasing the DVS crosslinker content within the gels in general, had the opposite effect, though the relatively high concentration of DVS within these gels (necessary to create a solid gel) also stimulated a mild subcutaneous inflammatory response in vivo and VCAM‐1 expression by endothelial cells (ECs) cultured atop; ICAM‐expression levels remained very low irrespective extent of DVS crosslinking or HA‐o content. The greatest EC attachment and proliferation (MTT assay) was observed on gels that contained the highest amount of HA‐o. The study shows that the beneficial EC response to HA‐o and biocompatibility of HA is mostly unaltered by their chemical derivatization and crosslinking into a hydrogel. However, the study also demonstrates that the relatively high concentrations of DVS, necessary to create solid gels, compromise their biocompatibility. Moreover, the poor mechanics of even these heavily crosslinked gels, in the context of vascular implantation, necessitates the investigation of other, more appropriate crosslinking agents. Alternately, the outcomes of this study may be used to guide an approach based on chemical immobilization and controlled surface‐presentation of both bioactive HA‐o and more biocompatible HMW HA on synthetic or tissue engineered grafts already in use, without the use of a crosslinker, so that improved, predictable, and functional endothelialization can be achieved, and the need to create a mechanically compliant biomaterial for standalone use, circumvented. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Sol–gel derived titania coating with immobilized bisphosphonate enhances screw fixation in rat tibia
Authors: Linderbäck Paula , Areva Sami , Aspenberg Per , Tengvall Pentti
Published: February 2010

A variety of surface modifications have been tested for the enhancement of screw fixation in bone, and locally delivered anti‐osteoporosis drugs such as bisphosphonates (BP) are then of interest. In this in vivo study, the impact of surface immobilized BP was compared with systemic BP delivery and screws with no BP. After due in vitro characterization, differently treated stainless steel (SS) screws were divided into four groups with 10 rats each. Three of the groups received screws coated with sol–gel derived TiO2 and calcium phosphate (SS+TiO2+CaP). One of these had no further treatment, one had alendronate (BP) adsorbed to calcium phosphate mineral, and one received systemic BP treatment. The fourth group received uncoated SS screws and no BP (control). The screw pullout force was measured after 4 weeks of implantation in rat tibiae. The immobilized amount and release rate of alendronate could be controlled by different immersion times. The SS+TiO2+CaP coating did not increase the pullout force compared to SS alone. Surface delivered alendronate enhanced the pullout force by 93% [p = 0.000; 95% Confidence Interval (CI): 67–118%] compared to SS, and by 39% (p = 0.044; 95% CI: 7–71%) compared to systemic alendronate delivery. Both surface immobilized and systemically delivered alendronate improved implant fixation. Also, locally delivered, that is, surface immobilized alendronate showed a better fixation than systemically delivered. Using sol–gel derived TiO2 as a platform, it is possible to administer controllable amounts of a variety of BPs. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res 2010
OP‐1 (BMP‐7) stimulates osteoprogenitor cell differentiation in the presence of polymethylmethacrylate particles
Authors: Kann Shawn , Chiu Richard , Ma Ting , Goodman Stuart B.
Published: February 2010

Polymethylmethacrylate (PMMA) particles have been shown to inhibit the differentiation, proliferation, and mineralization of osteoprogenitor cells in vitro. In this study, we investigated the effects of OP‐1 (BMP‐7) on the osteogenesis of MC3T3‐E1 osteoprogenitor cells exposed to PMMA particles in vitro. MC3T3‐E1 cells challenged with PMMA particles on the 1st day of differentiation in osteogenic culture showed a significant dose‐dependent decrease in mineralization and alkaline phosphatase expression over a 20‐day culture period. Exposure of these cells to OP‐1 (200 ng/mL) during days 1–4, 1–20, and 4–20 in the presence of PMMA particles resulted in significant increases in mineralization and alkaline phosphatase expression at all particle doses. Addition of OP‐1 to MC3T3‐E1 cultures challenged with PMMA particles on the 4th day of differentiation in osteogenic media also resulted in significant increases in mineralization and alkaline phosphatase expression. This study has shown that OP‐1 stimulates osteogenesis in MC3T3‐E1 osteoprogenitor cells that have been inhibited by PMMA particles. Local administration of OP‐1 to the site of osteolysis may be a potential adjunctive therapy to reverse the bone destruction due to wear particles. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Effects of surface chemistry prepared by self‐assembled monolayers on osteoblast behavior
Authors: Nakaoka Ryusuke , Yamakoshi Yoko , Isama Kazuo , Tsuchiya Toshie
Published: February 2010

A surface of biomaterials is known to affect the behavior of cells after their adhesion on the surface, indicating that surface characteristics of biomaterials play an important role in cell adhesion, proliferation, and differentiation. To assess the effects of functional groups on biomaterial surface, normal human osteoblasts (NHOsts) were cultured on surfaces coated with self‐assembled monolayers (SAMs) containing various functional groups, and the adhesion, proliferation, differentiation, and gap junctional intercellular communication (GJIC) of the NHOsts were investigated. In the case of SAM with terminal methyl groups (hydrophobic surface), NHOst adhesion and proliferation was less prevalent. In contrast, NHOsts were adhered well on SAMs with hydroxyl, carboxyl, amino, phosphate, and sulfate group, which are relatively hydrophilic, their proliferation and differentiation level were dependent on the type of functional groups. Especially, when they were cultured on either SAMs with phosphate or sulfate group, both their alkaline phosphate activity and the calcium deposition by them were enhanced more than those cultured on a collagen‐coated dish. More interestingly, GJIC of NHOsts, which has been reported to play a role in cell differentiation as well as homeostasis of cells, were not significantly different among the SAM surfaces tested. These suggest that a specific functional group on a material surface can regulate NHOst adhesion, proliferation, and differentiation via cell‐functional group interaction without influencing their homeostasis. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Change in neuron aggregation and neurite fasciculation on EVAL membranes modified with different diamines
Authors: Wang Jyh‐Horng , Lin Ui‐Hsiang , Lin Chun‐Hung , Chung Yi‐Chen , Chen Chi‐Ruei , Kao Yu‐Chun , Lai Juin‐Yih , Young Tai‐Horng
Published: February 2010

In this study, we modified poly(ethylene‐co‐vinyl alcohol) (EVAL) membranes by the covalent bonding of diamines via epoxidation of surface hydroxyl groups of EVAL to analyze the effect of immobilized diamines with different carbon chain length on the cultured cerebellar granule neurons. Morphological studies showed that neurons seeded on the diamine‐immobilized EVAL membrane were able to survive and regenerate with formation of an extensive neuritic network. Furthermore, cultured neurons showed that the presence of diamine with different carbon chain length was able to effectively regulate the neuron adhesion, migration, aggregation, and neurite growth pattern, but mediated neuronal activity with equal efficacy. The short‐chain amine stimulated neuron migration, aggregation, and neurite fasciculation, whereas the long carbon chain diamine maintained single neuron distribution with the defasciculated feature of the neurite. Although it is known that positively charged amine molecules can interact directly with cell surface proteoglycans to mediate cell attachment, this study further demonstrated that the terminal primary amine with different carbon chain length is involved in mediating cell–substrate interaction to further regulate neuron aggregation and neurite fasciculation. This indicates a delicate interaction of neuron with the immobilized diamine molecules on the EVAL membrane surface. This work is encouraging because the diamine‐ immobilized EVAL membranes can be applied for the establishment of different neural culture systems useful for future investigations of neuron biology under in vitro conditions. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
In vivo wound healing and antibacterial performances of electrospun nanofibre membranes
Authors: Liu Xin , Lin Tong , Fang Jian , Yao Gang , Zhao Hongqiong , Dodson Michael , Wang Xungai
Published: February 2010

In this work, nanofibre membranes have been produced from polyvinyl alcohol (PVA), polycaprolactone (PCL), polyacrylonitrile (PAN), poly (vinylidene fluoride‐co‐hexafluoropropene) (PVdF‐HFP), and polymer blend of PAN and polyurethane (PEU) using an electrospinning technique, and wound healing performance of the as‐spun nanofibre membranes was examined in vivo using female Sprague‐Dawley rats. To understand the nutrition effect, a wool protein was coated on PVA and PCL nanofibres and incorporated into PVA nanofibres via coelectrospinning of a PVA solution containing the wool protein. Silver nanoparticles were also applied to PVA nanofibres to improve antibacterial activity. It was found that the wound healing performance is mainly influenced by the porosity, air permeability, and surface wettability of the nanofibre membranes. A nanofibre membrane with good hydrophilicity and high porosity considerably facilitates the healing of wound especially at the early healing stage. However, the fiber diameter and antibacterial activity have little effect on the wound healing efficiency. As pores in nanofibre membranes are typically smaller than that of conventional cotton gauze, the nanofibre membrane should be able to decontaminate and prevent exogenous infections via sieve effect. This work provides basic understanding of material structure–property relationship for further design of efficient nanofibre‐based wound dressing materials. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
A model for studying human articular cartilage integration in vitro
Authors: Enders J. Tyler , Otto Thomas J. , Peters H. Charlie , Wu Jin , Hardouin Scott , Moed Berton R. , Zhang Zijun
Published: February 2010

One of the major obstacles hindering cartilage repair is the integration of the reparative cartilage with the recipient cartilage. The purpose of this study was to develop an in
vitro model that can be conveniently applied to simulate and improve the integration of tissue engineered cartilage with native articular cartilage. This model, a cartilage integration construct, consists of a cartilage explant and isolated chondrocytes. The explant was anchored to agarose gel on a culture plate as agarose gelation at 4°C to seal the gap between the bottom of the explant and culture plate surface. Isolated chondrocytes were added and confined in the defect created in the center of the explant. After 4 weeks of culture, neocartilage containing proteoglycans and type II collagen was formed. Minimal integration occurred between the neocartilage and the cartilage explant, resembling the failure of cartilage integration manifested in experimental and clinical cartilage repair. In this model, agarose gel anchors the explant onto culture plate by altering temperatures and effectively prevents “leakage” of the isolated chondrocytes from the defect of the explant. This model provides a convenient simulation of the cartilage integration process in vitro and has applications in studies of cartilage integration and cartilage tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res part A, 2010
Endothelial and stem cell interactions on dielectrophoretically aligned fibrous silk fibroin‐chitosan scaffolds
Authors: Gupta Vishal , Davis Greg , Gordon Alexander , Altman Andrew M. , Reece Gregory P. , Gascoyne Peter R. , Mathur Anshu B.
Published: February 2010

Regenerative tissue engineering requires biomaterials that would mimic structure and composition of the extracellular matrix to facilitate cell infiltration, differentiation, and vascularization. Engineered scaffolds composed of natural biomaterials silk fibroin (SF) and chitosan (CS) blend were fabricated to achieve fibrillar nano‐structures aligned in three‐dimensions using the technique of dielectrophoresis. The effect of scaffold properties on adhesion and migration of human adipose‐derived stem cells (hASC) and endothelial cells (HUVEC) was studied on SFCS (micro‐structure, unaligned) and engineered SFCS (E‐SFCS; nano‐structure, aligned). E‐SFCS constituted of a nano‐featured fibrillar sheets, whereas SFCS sheets had a smooth morphology with unaligned micro‐fibrillar extensions at the ends. Adhesion of hASC to either scaffolds occurred within 30 min and was higher than HUVEC adhesion. The percentage of moving cells and average speed was highest for hASC on SFCS scaffold as compared to hASC cocultured with HUVEC. HUVEC interactions with hASC appeared to slow the speed of hASC migration (in coculture) on both scaffolds. It is concluded that the guidance of cells for regenerative tissue engineering using SFCS scaffolds requires a fine balance between cell–cell interactions that affect the migration speed of cells and the surface characteristics that affects the overall adhesion and direction of migration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Microbial biofilm growth versus tissue integration on biomaterials with different wettabilities and a polymer‐brush coating
Authors: Subbiahdoss Guruprakash , Grijpma Dirk W. , van der Mei Henny C. , Busscher Henk J. , Kuijer Roel
Published: February 2010

Biomaterials‐associated infections (BAI) constitute a major clinical problem and often necessitate implant replacement. In this study, the race for the surface between Staphylococcus epidermidis ATCC 35983 and U2OS osteosarcoma cells is studied on biomaterials with different wettabilities and on a polymer‐brush coating. S. epidermidis was deposited on the different surfaces in a parallel plate flow chamber and then U2OS cells were seeded. Subsequently, staphylococci and U2OS cells were allowed to grow simultaneously on the surfaces for 48 h under low flow conditions. The presence of staphylococci reduced cell growth on all surfaces, but adhering cells spread equally well in the absence and presence of staphylococci. A hydrophilic polymer‐brush coating discouraged bacterial and cellular adhesion and growth. Thus, whereas the biomaterials evaluated support both biofilm formation and tissue integration, polymer‐brush coatings support neither. Therewith, the outcome of the race for the surface on these surfaces remains uncertain, emphasizing the need for biofunctionalized surfaces that discourage biofilm formation and support tissue growth at the same time. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Three step derivation of cartilage like tissue from human embryonic stem cells by 2D‐3D sequential culture in vitro and further implantation in vivo on alginate/PLGA scaffolds
Authors: Bai Hai Yan , Chen Gui An , Mao Gen Hong , Song Tian Ran , Wang Yan Xia
Published: February 2010

In this study a three step culture system, 2D‐3D sequential culture in vitro and further implantation in vivo was developed to induce human embryonic stem cells (hESCs) into cartilage like tissues. Five‐day‐old embryoid bodies were plated for chondrogenic induction for 27 days (step1), then the cells were suspended in alginate and seeded onto polylactic‐co‐glycolic acid (PLGA) scaffolds for 3D cultivation for 7 days (step 2) and the cells/alginate/PLGA complexes were further transplanted into nude mice for 8 weeks (step 3). At same time, some of complexes were cultured in vitro up to 8 weeks. At the end of step 1, cells exhibited fibroblast‐like morphology and expressed chondrocyte‐specific markers, Sox 9 and collagen II. During the following 8 weeks of 3D cultivation in vitro, cells displayed spherical morphology, decreased immunoreactivity to Sox‐9 and increased one to collagen II, demonstrated further differentiation to mature chondrocyte. In implanted grafts, not only cells appeared typical chondrocytes shape and markers but also cartilage like tissues were formed. These results indicate that 2D‐3D sequential culture in vitro is an efficient protocol to induce hESCs differentiates into chondrocytes, while the three step culture system may be an appropriate procedure to derive cartilage like tissues from hESCs. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Cell culture platform with mechanical conditioning and nondamaging cellular detachment
Authors: Lee Elaine L. , von Recum Horst A.
Published: February 2010

Cells implanted after injury may remodel undesirably with improper mechanical stimulation from surrounding tissue. Proper conditioning of tissue engineered constructs before implantation can lead to suitable tissue architectures, along with an extracellular matrix (ECM) environment that more closely mimics native tissue. Additionally, cell implantation without bulky polymeric scaffolding is often desirable. Previous researchers have created devices capable of applying mechanical forces to cells (e.g., stretch) but cellular removal from these devices, such as by trypsin, often results in irreversible damage. Conversely, devices are available that can detach intact cells, but these are inelastic, nonstretchable substrates. We have created a cell culture platform that allows for mechanical conditioning and then subsequent nondamaging detachment of those cells. We have modified silicone culture surfaces, to incorporate thermally responsive polymers of N‐isopropylacrylamide (NIPAAm) to create an elastic substrate that can also change surface properties with temperature change. A copolymer of NIPAAm and 10% w/w acrylic acid (AAc) was conjugated to an amine‐bonded silicone surface through carbodiimide chemistry. Cells were able to attach to the resulting surfaces at 37°C and showed detachment by rounded morphology at 25°C. Following mechanical stretching, cells were still able to spontaneously detach from these modified silicone surfaces with temperature change. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Treasurer vs. CFO: Vivendi's liquidity disaster
Authors: Le Guyader Louis P.
Published: February 2010

What happens when the CFO and the treasurer clash over liquidity management and reporting? For the French company Vivendi, it caused them to run afoul of the Securities and Exchange Commission! The author explains what happened so other firms can avoid similar tragedies. © 2010 Wiley Periodicals, Inc.
Enhancing Information for Investors
Authors: Cole Cathy J.
Published: February 2010

Many publicly held companies provide financial information to investors in a variety of forms and formats. But not all companies provide the same level of information, or devote the same amount of resources to tailor information to users' needs. How can they provide a more user‐focused view of the company's financial condition? © 2010 Wiley Periodicals, Inc.
A system of cost variances to evaluate sustainability efforts
Authors: Dutta Saurav K. , Lawson Raef A. , Marcinko David J.
Published: February 2010

Organizations today face increasing demands to engage in environmental initiatives and to manage the environmental risks associated with their operations. This article shows how a well‐known technique of cost management—variance analysis—can be used to link performance evaluation systems to sustainability strategies. © 2010 Wiley Periodicals, Inc.
Information search using the balanced scorecard: What matters?
Authors: Neumann Bruce R. , Roberts Michael L. , Cauvin Eric
Published: February 2010

Information overload has been rightly called one of the "deadly sins" of balanced scorecards. To help organizations make their scorecards balanced, this article discusses how many and what types of measures to use. © 2010 Wiley Periodicals, Inc.
Cerium (IV) ammonium nitrate as an efficient Lewis acid for the one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones and their corresponding 2‐(1H) thiones
Authors: Sadek Kamal Usef , Al‐Qalaf Fawzia , Abdelkhalik Mervat Mohammed , Elnagdi Mohamed Hilmy
Published: February 2010

magnified image

A simple and highly efficient procedure for the Biginelli condensation reaction of aldehydes, β‐ketoesters, urea, or thiourea catalyzed by Ceric ammonium nitrate (CAN) as a Lewis‐acid at ambient temperature is described. The procedure proved to be simple and of high yield. J. Heterocyclic Chem., (2010).
1H‐Benzimidazole‐2‐acetonitriles as synthon in fused benzimidazole synthesis
Authors: Dawood Kamal M. , Elwan Nehal M. , Farahat Abdelbasset A. , Abdel‐Wahab Bakr F.
Published: February 2010

magnified image

This review summarizes the methods for preparing 1H‐benzimidazole‐2‐acetonitriles and their reactions in the past years, some of which have been applied to the synthesis of biologically active molecules. The main reactions are divided into several groups according to some types of the fused benzimidazoles. J. Heterocyclic Chem., (2010)
Vulnerability to climate change in rural Ghana: Mainstreaming climate change in poverty‐reduction strategies
Authors: Dasgupta Aisha , Baschieri Angela
Published: February 2010

This paper argues that poverty assessments that use standard money‐metric indicators of poverty overlook the welfare of communities highly vulnerable to weather‐related extremes, and that an assessment of vulnerability to climate change should be an integral part of poverty assessment. Using Ghana as a case study, this paper evaluates to what extent the standard money‐metric measures of poverty represent the welfare of those households vulnerable to weather‐related extremes. In addition, the paper illustrates the importance of mainstreaming climate change into development strategies, highlights the importance of integrating vulnerability assessments and stresses the need for developing adaptation strategies for poverty alleviation. Copyright © 2010 John Wiley & Sons, Ltd.