bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation and biocompatibility of a poly(propylene fumarate)‐based/alumoxane nanocomposite for bone tissue engineering
Authors: Mistry A.S. , Mikos A.G. , Jansen J.A. 
Published: June 2007

AbstractIn this work, we evaluated the in vitro cytotoxicity and in vivo biocompatibility of a novel poly(propylene fumarate) (PPF)‐based/alumoxane nanocomposite for bone tissue engineering applications. The incorporation of functionalized alumoxane nanoparticles into the PPF‐based polymer was previously shown to significantly increase the material's flexural mechanical properties. In the current study, samples underwent accelerated in vitro degradation to allow the study of biological responses to these materials over the course of their degradation on a shortened timescale. The polymer, a macrocomposite composed of the polymer and micron‐sized particles, and the nanocomposite were evaluated at three stages of degradation for in vitro cytotoxicity with a fibroblast cell line and in vivo soft‐tissue response after 3 and 12 weeks of implantation in adult goats. All three material groups experienced mass loss during degradation, but the nanocomposite group eroded significantly faster than the other groups. Nondegraded materials demonstrated minimal cytotoxicity and a minor inflammatory response in soft tissue. On the contrary, predegraded samples elicited more pronounced responses, though these were due to the increase in surface area, surface roughness, and fragmentation associated with the degradation process. The presence of alumoxane nanoparticles in the PPF‐based nanocomposite did not significantly affect its cytotoxicity or biocompatibility. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Characterization of the surface immobilized synthetic heparin binding domain derived from human fibroblast growth factor‐2 and its effect on osteoblast differentiation
Authors: Lee Jue‐Yeon , Choo Jung‐Eun , Choi Young‐Sook , Lee Kuen‐Yong , Min Do‐Sik , Pi Sung‐Hee , Seol Yang‐Jo , Lee Seung‐Jin , Jo In‐Ho , Chung Chong‐Pyoung , Park Yoon‐Jeong 
Published: June 2007

AbstractFibroblast growth factor (FGF)‐2 regulates a variety of cellular functions, such as proliferation and differentiation, by binding to cell surface FGF receptors (FGFRs) in the presence of heparin proteoglycans. FGF‐2 is known as a heparin‐binding growth factor, but the localization of the heparin binding site has not been fully investigated until now. We used two potential heparin binding domains of FGF‐2, the residues 105–111 (F105, YKRSRYT) and 119–135 (F119, KRTGQYKLGSKTGPGQK). Peptides could be stably immobilized onto the surface of tissue culture plates. Using solid phase binding assays, we demonstrated that both peptides had higher binding affinity toward heparin compared with nonbinding control sequence. The biological significance of these sites was tested by cell attachment and osteoblast differentiation studies. Cell attachment to the peptides F105 and F119 increased in a dose‐dependent manner. Heparin and heparinase treatments decreased cell adhesion to both F105 and F119. This demonstrates that both F105 and F119 interact with cell‐surface heparan sulfate proteoglycans, suggesting that FGF‐2 has two heparin binding sites. In addition, osteoblast differentiation, confirmed by ALPase activity and mineralization, was increased by surface immobilized peptide F105 and F119. Taken together, these heparin binding peptides could be applied as biological agents enhancing osteoblast differentiation as well as surface modification tools in the tissue regeneration area, especially for bone regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Osterix/Sp7 regulates mesenchymal stem cell mediated endochondral ossification
Authors: Kaback Lee A. , Soung Do Y. , Naik Amish , Smith Nathan , Schwarz Edward M. , O'Keefe Regis J. , Drissi Hicham 
Published: June 2007

AbstractWe investigated the expression and regulation of the zinc finger protein Osterix (Osx) during endochondral ossification in mice. In studies to determine the temporal and spatial regulation of Osx mRNA and protein during embryogenesis we found it to be present throughout development, but its expression is restricted to the immature chondro/osteoprogenitor cells and mature osteoblasts, excluding hypertrophic chondrocytes. Using a fracture model, we show a consistent pattern of Osx protein expression in mesenchymal progenitor cells in the periosteum and immature chondrocytes and osteoblasts embedded in the fracture callus. In contrast, hypertrophic chondrocytes, vessels and fibrous tissue were devoid of Osx expression. Additionally, using RNA isolated from fracture callus throughout the healing process, we observe that Osx transcripts parallel that of Runx2 and differentially overlap both cartilage and bone phenotypic markers. Furthermore, using limb bud‐derived MLB13MYC Clone 17 cells, we show that PTHrP inhibited chondrocyte maturation while it enhanced mRNA levels of Osx in these chondro/osteoprogenitor cells. Gain and loss of function of Osx function experiments with these cells demonstrated that Osx serves as an inhibitor of chondrogenesis and chondrocyte maturation, while it promotes osteoblast maturation. Together, our findings provide the first demonstration of the molecular mechanisms underlying Osx inhibition of chondrocyte differentiation, and further suggest a role for this transcription factor in mediating endochondral ossification during bone repair. J. Cell. Physiol. 214:173–182, 2008. © 2007 Wiley‐Liss, Inc.
Enhanced VDUP‐1 gene expression by PPARγ agonist induces apoptosis in human macrophage
Authors: Billiet L. , Furman C. , Larigauderie G. , Copin C. , Page S. , Fruchart J.‐C. , Brand K. , Rouis M. 
Published: June 2007

AbstractThe fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredoxin‐1 (Trx‐1) plays a major role in the regulation of cellular redox balance, with resultant effects on gene expression and cellular responses including cell growth and death. Trx‐1 activity is inhibited by interaction with vitamin D‐upregulated protein‐1 (VDUP‐1). Peroxisome proliferator‐activated receptor gamma (PPARγ) is expressed by human monocyte‐derived macrophages (HMDM) and PPARγ agonism has been reported to decrease expression of inflammatory genes and to promote apoptosis of these cells. To determine whether VDUP‐1 may be involved in regulating the effects of PPARγ agonists in macrophages, we investigated the effect of a synthetic PPARγ agonist (GW929) on the expression of VDUP‐1 in HMDM. GW929 concentration‐dependently increased HMDM expression of VDUP‐1 (mRNA and protein). Transfection of different fragments of the VDUP‐1 promoter as well as gel shift analysis revealed the presence of functional PPARγ response elements (PPRE) in the promoter. Under conditions in which PPAR agonism altered levels of VDUP‐1, caspase‐3 activity, and macrophage apoptosis were also elevated. The results suggest that PPARγ activation stimulates apoptosis in human macrophages by altering the cellular redox balance via regulation of VDUP‐1. J. Cell. Physiol. 214:183–191, 2008. © 2007 Wiley‐Liss, Inc.
The novel correlation of carbonic anhydrase II and anion exchanger 1 in gills of the spotted green pufferfish, Tetraodon nigrovirids
Authors: Tang C.H. , Lee T.H. 
Published: June 2007

AbstractA novel relationship between branchial carbonic anhydrase II (CAII) and anion exchanger 1 (AE1) was investigated in the euryhaline spotted green pufferfish (Tetraodon nigroviridis). The immunoblots revealed that AE1 was only detected in the membrane fraction of gills while CAII can be probed both in the membrane and cytosol fractions of gills. CAII protein abundance in the membrane fraction is salinity dependent. Immunological detection of the membrane fraction CAII protein in gills showed 3.9‐fold higher in the hyposmotic (freshwater) group than the hyperosmotic (seawater;35‰) group. In contrast, there was no change in the protein level of cytosolic CAII between seawater and freshwater groups. The whole‐mount immunocytochemical staining demonstrated that both AE1 and CAII were colocalized to the Na+/K+‐ATPase‐immunoreactive cells in gill epithelium of the pufferfish. The interaction between CAII and AE1 was further identified by co‐immunoprecipitation because AE1 was detected in the immunoprecipitates of CAII and vice versa. Our results showed that in pufferfish gills CAII was not only expressed in the cytosol to produce the substrate for AE1 transport during Cl− influx but also associated with the plasma membrane via AE1. Obviously, it is essential for the physiological function of AE1 to interact with CAII in the membrane of gill Na+/K+‐ATPase‐immunoreactive cells. To our knowledge, this is the first study to demonstrate the interaction of branchial CAII and AE1 in fish. The novel correlation proposed a new model of Cl−/HCO3− transport in gills of the teleosts. J. Exp. Zool. 307A:411–418, 2007. © 2007 Wiley‐Liss, Inc.
Poverty, networks and location: the determinants of job‐search in South Africa
Authors: Hinks Timothy 
Published: June 2007

AbstractPrevious work into the decision to search or not for work when unemployed has found that local unemployment rates, education level and social networks are important in the case of South Africa. This paper introduces a number of additional variables in order to test what other factors are associated with this decision. It is found that previous work experience, job security of the households employed members, whether there is a state pensioner in the unemployed person's household, poverty and proximity to public transport are all connected to the decision to varying degrees. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of [2H3]‐labelled sulfamethoxazole and its main urinary metabolites
Authors: Heinkele Georg , Mürdter Thomas E. 
Published: June 2007

AbstractSulfamethoxazole was labelled at positions 3, 5, and 4′ by H/D exchange in a mixture of 5% 2H2SO4 and 95% 2H2O (v/v) under reflux for 72h with good isotope incorporation and acceptable yield. Subsequently, [2H3]‐sulfamethoxazole‐N1‐glucuronide and [2H3]‐N4‐acetyl‐sulfamethoxazole were synthesized. Copyright © 2007 John Wiley & Sons, Ltd.
Use of isotope effects to determine enzyme mechanisms
Authors: Cleland W. W. 
Published: June 2007

AbstractIsotope effects are a powerful tool for determining the mechanisms of enzymatic reactions. Methods for measurement of isotope effects are reviewed and the equations that describe observed isotope effects and permit determination of intrinsic isotope effects on the isotope‐sensitive step are presented. Aspartate transcarbamoylase is used as an example for how the kinetic mechanism can be determined by observing the size of an isotope effect as a function of the concentration of another substrate. Cytidine, adenosine and AMP deaminases are used to illustrate determining the relative rates of steps in the mechanism. Determination of chemical mechanism is illustrated by data for malic enzyme, OMP decarboxylase, aspartate transcarbamoylase, L‐ribulose‐5‐P 4‐epimerase, oxalate decarboxylase, tryptophan 2‐monooxygenase and the K58A mutant of aspartate aminotransferase when rescued by ammonia. Determination of transition state structure is illustrated by data for formate dehydrogenase, prephenate dehydrogenase, chorismate mutase, as well as for enzymes that catalyze phosphoryl and acyl transfer. Copyright © 2007 John Wiley & Sons, Ltd.
Expression of decorin, a small leucine‐rich proteoglycan, as a prognostic factor in soft tissue tumors
Authors: Matsumine Akihiko , Shintani Ken , Kusuzaki Katsuyuki , Matsubara Takao , Satonaka Haruhiko , Wakabayashi Toru , Iino Takahiro , Uchida Atsumasa 
Published: June 2007

AbstractBackground and ObjectivesDecorin is a major extracellular matrix protein which has recently become the focus of various cancer studies. However, there have so far been no reports describing the clinicopathological implications of decorin in soft tissue tumors. The aim of this study was to examine whether decorin expression is a prognostic factor in soft tissue tumors.MethodsDecorin expression was examined in 85 samples obtained from 77 patients by real‐time quantitative PCR and immunohistochemistry.ResultsLower levels of decorin were expressed in liposarcoma and malignant peripheral nerve sheath tumor than in lipoma (<0.01) and neurofibroma (P < 0.05), respectively. An immunohistochemical analysis for spindle‐cell sarcomas demonstrated decorin protein to be produced by myofibroblastic cells in the peripheral stromal extracellular spaces. On a Kaplan–Meier analysis, lower levels of decorin were associated with lower disease‐free and overall survival rates (P < 0.05) in 31 spindle‐cell sarcomas. A multivariate analysis revealed a significant correlation between a reduced decorin expression and a poor disease‐free survival (P = 0.04). In all seven patients with recurrent or metastatic lesions, the decorin expression levels were lower in secondary lesions than in primary lesions.ConclusionsA reduced decorin expression was found to be a useful biomarker of aggressiveness in soft tissue tumor. J. Surg. Oncol. 2007;96:411–418. © 2007 Wiley‐Liss, Inc.
Feasibility of two multidimensional techniques, heart‐cut MDGC and GC×GC, for the separation of PCBs and PBDEs
Authors: Gómara Belén , Bordajandi Luisa R. , González María José 
Published: June 2007

AbstractThe feasibility of heart‐cut MDGC‐ECD and GC×GC‐μECD for the separation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) has been evaluated. Among the different column combinations tested, the best results were obtained when using either a DB‐5 type or an HT‐8 column as the first dimension combined with a mid‐polar stationary phase (50% phenyl) as the second dimension. The coelutions between the target PCBs and PBDEs in the first dimension were satisfactorily resolved once transferred to the second column. Repeatability and intermediate precision were satisfactory in both systems, considering retention times in both dimensions. Nevertheless, peak area/volume precision was better for heart‐cut MDGC since software for the data analysis in the case of GC×GC was still under development. The need for multiple injections of the same extract on the heart‐cut MDGC system was the main drawback since the analysis time it increased. GC×GC becomes then a valuable alternative able to achieve the same performance in one injection. However, the GC×GC data analysis is still very time‐consuming and needs further development. The applicability of both separation techniques was shown using a human breast milk sample with low concetrations of PCBs (0.2–227 pg/g fresh weight) and PBDEs (1.2–41 pg/g fresh weight).
Capillary electrophoresis of viruses, subviral particles and virus complexes
Authors: Kremser Leopold , Bilek Gerhard , Blaas Dieter , Kenndler Ernst 
Published: June 2007

AbstractCZE and CIEF were so far applied to the analysis of tobacco mosaic virus, Semliki forest virus, human rhinovirus, adenovirus, norovirus and the bacteriophages T5 and MS2. The concentration of viral or subviral particles, of capsid proteins and viral genomes were determined, their electrophoretic mobilities and pI values were measured and bioaffinity reactions between viruses and antibodies, antibody fragments and receptor fragments were assessed. The role of detergents added to the BGE to obtain reproducible electrophoretic conditions was elucidated. The analytes were detected via their UV‐absorbance or via fluorescence after derivatization of the viral capsid, the nucleic acid, or both. A new dimension to the detection is added by the possibility of making use of the viral infectivity. At least in theory, this allows for the unequivocal identification of a single infectious virus particle after collection at the capillary outlet. This review summarizes the 25 papers so far published on this topic.
Making strategy real: Bringing people together toward a common cause
Authors: Beatty Katherine Colarelli , Quinn Laura 
Published: June 2007

AbstractThe hardest part of strategic leadership is getting people throughout the organization—from the executive team to the people on the front lines—to think and act similarly when making or carrying out strategy, even as the business environment continually places new demands on the organization. For leaders, closing the gap between strategy and execution requires focusing on clear priorities, creating common understanding through real dialogue, and engendering a learning orientation in the organization.
Toughening of Polylactide by Melt Blending with a Biodegradable Poly(ether)urethane Elastomer
Authors: Li Yongjin , Shimizu Hiroshi 
Published: June 2007

AbstractMelt blending of polylactide (PLA) and a biodegradable poly(ether)urethane (PU) elastomer has been performed in an effort to toughen the polylactide without compromising its biodegradability and biocompatibility. The miscibility, phase morphology, mechanical properties, and toughening mechanism of the blend were investigated. The blend was found by dynamic mechanical analysis to be a partially miscible system with shifted glass transition temperatures. The PU elastomer was dispersed in the PLA matrix with a domain size of sub‐micrometer scale. The addition of PU elastomer not only accelerated the crystallization speed, but also decreased the crystallinity of the PLA. With an increase in PU content, the blend shows decreased tensile strength and modulus; however, the elongation at break and the impact strength were significantly increased, indicating the toughening effects of the PU elastomer on the PLA. The brittle fracture of neat PLA was gradually transformed into ductile fracture by the addition of PU elastomer. It was found that the PLA matrix demonstrates large area, plastic deformation (shear yielding) in the blend upon being subjected the tensile and impact tests, which is an important energy‐dissipation process and leads to a toughened, biodegradable polymer blend.magnified image
Polyelectrolyte Complexes Based on (Quaternized) Poly[(2‐dimethylamino)ethyl methacrylate]: Behavior in Contact with Blood
Authors: Yancheva Elena , Paneva Dilyana , Danchev Dobri , Mespouille Laetitia , Dubois Philippe , Manolova Nevena , Rashkov Iliya 
Published: June 2007

AbstractPolyelectrolyte complexes (PECs) between (quaternized) poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) and (crosslinked) N‐carboxyethylchitosan (CECh) or poly(2‐acrylamido‐2‐methylpropane sodium sulfonate) (PAMPSNa) were prepared and characterized in terms of their stability, equilibrium water content, and surface morphology. The evaluation of the behavior of the studied PECs in contact with blood revealed that the (crosslinked) CECh/(quaternized) PDMAEMA complexes had lost the inherent PDMAEMA cytotoxicity but still preserved haemostatic activity. In contrast, the complex formation between (quaternized) PDMAEMA and PAMPSNa allowed the preparation of materials with improved blood compatibility.magnified image
Main‐Chain Liquid Crystalline Polymers Based on Bis‐Etherified 9,9‐Dihexyl‐2,7‐bis(4′‐hydroxy‐1,1′‐biphen‐4‐yl)fluorenes
Authors: Sović Tanja , Kappaun Stefan , Koppitz Andreas , Zojer Egbert , Saf Robert , Bartl Karin , Fodor‐Csorba Katalin , Vajda Aniko , Diele Siegmar , Pelzl Gerhard , Slugovc Christian , Stelzer Franz 
Published: June 2007

AbstractA series of liquid crystalline compounds based on 2,7‐bis(biphenyl)fluorenes was synthesised by a Suzuki cross‐coupling reaction and subsequent etherification with different bromoalkenes. By simple variations of the chain lengths the temperature range in which the nematic mesophase is present could be tuned. The described approach offers the possibility of covalent incorporation of the mesogens into polymers via olefin metathesis techniques, resulting in enlarged stability of the mesophase. Monomers and polymers could be easily aligned on rubbed polyimide substrates as revealed by polarised absorption spectroscopy.magnified image
Tailored Branched Polyolefins by Metallocene Catalysis
Authors: Kaminsky Walter , Hoff Matthias , Derlin Stefanie 
Published: June 2007

AbstractMetallocene/methylaluminoxane catalysts are able to design copolymers with tailored architectures. It is possible to copolymerize ethene with higher α‐olefins and cyclic olefins. The terpolymer of ethene/1‐hexene/norbornene shows a better flexibility than the ethene/norbornene copolymer by a similar high transparency. The influence of the comonomer concentration on activity, molecular weight, and glass transition temperature is given as well as the comparison to 1‐hexene/norbornene and propene/norbornene copolymers. Hexene/norbornene copolymers were found to have a predominant alternating microstructure.magnified image
Microwave‐Assisted Synthesis and Characterization of Poly(ε‐caprolactone)/Montmorillonite Nanocomposites
Authors: Liao Liqiong , Zhang Chao , Gong Shaoqin 
Published: June 2007

AbstractPoly(ε‐caprolactone) (PCL)/montmorillonite (MMT) nanocomposites were prepared by in situ ring‐opening polymerization of ε‐caprolactone in the presence of MMT modified by hydroxyl‐group containing alkylammonium cation (Cloisite®30B) in a single mode microwave oven. For the polymerization mixtures, plateaus or exothermal peaks were observed in their temperature‐time profiles and can be attributed to the heat‐generating nature of the ring‐opening polymerization. The morphologies of the nanocomposites showed a predominantly exfoliated structure. The mechanical properties of the nanocomposites were evaluated via dynamic mechanical analysis. Compared with that of the recovered PCL matrix, the mechanical properties of the PCL/Cloisite®30B nanocomposites showed obvious improvement.magnified image
Synthesis and Layer‐by‐Layer Deposition of Spherical Poly(3,4‐ethylenedioxythiophene) Nanoparticles ‐ Toward Fast Switching Times between Reduced and Oxidized States
Authors: Müller Kevin , Park Mi‐Kyoung , Klapper Markus , Knoll Wolfgang , Müllen Klaus 
Published: June 2007

AbstractA microemulsion polymerization for the synthesis of poly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles is described. Spherical and electrically conducting PEDOT particles with diameters as small as 27 ± 8 nm were obtained by using decyltrimethylammonium bromide as a cationic surfactant. PEDOT nanoparticle multilayers, alternated with poly(styrene sulfonate), were prepared by the layer‐by‐layer deposition technique. Electrochemical surface plasmon resonance experiments revealed a ten‐fold increase in the switching time between redox states as compared with Baytron P/poly(ethyleneimine) multilayers. The enhanced charge transport can be attributed to an improved diffusion of the charge‐balancing counterions into the PEDOT nanoparticles.magnified image