bluuebunny/crossref_metadata_2025_split huggingface dataset:
TOPCAT‐NP: a minimum information requirement model for simulation of flow and nutrient transport from agricultural systems
Authors: Quinn P. F. , Hewett C. J. M. , Dayawansa N. D. K. 
Published: November 2007

AbstractFuture catchment planning requires a good understanding of the impacts of land use and management, especially with regard to nutrient pollution. A range of readily usable tools, including models, can play a critical role in underpinning robust decision‐making. Modelling tools must articulate our process understanding, make links to a range of catchment characteristics and scales and have the capability to reflect future land‐use management changes. Hence, the model application can play an important part in giving confidence to policy makers that positive outcomes will arise from any proposed land‐use changes. Here, a minimum information requirement (MIR) modelling approach is presented that creates simple, parsimonious models based on more complex physically based models, which makes the model more appropriate to catchment‐scale applications. This paper shows three separate MIR models that represent flow, nitrate losses and phosphorus losses. These models are integrated into a single catchment model (TOPCAT‐NP), which has the advantage that certain model components (such as soil type and flow paths) are shared by all three MIR models. The integrated model can simulate a number of land‐use activities that relate to typical land‐use management practices. The modelling process also gives insight into the seasonal and event nature of nutrient losses exhibited at a range of catchment scales. Three case studies are presented to reflect the range of applicability of the model. The three studies show how different runoff and nutrient loss regimes in different soil/geological and global locations can be simulated using the same model. The first case study models intense agricultural land uses in Denmark (Gjern, 114 km2), the second is an intense agricultural area dominated by high superphosphate applications in Australia (Ellen Brook, 66 km2) and the third is a small research‐scale catchment in the UK (Bollington Hall, 2 km2). Copyright © 2007 John Wiley & Sons, Ltd.
Reactive oxygen species‐dependent destruction of MEK and Akt in Manumycin stimulated death of lymphoid tumor and myeloma cell lines
Authors: Sears Khandra T. , Daino Hanako , Carey Gregory B. 
Published: November 2007

AbstractManumycin‐A (Man‐A) is a farnesyltransferase inhibitor (FTI), which was originally identified as an effective tumoricide against several cancers, especially ones harboring constitutively active Ras. However, it is becoming apparent that Man‐A can stimulate tumor death independently of FTases. Antioxidant treatment blocked Man‐A‐stimulated DNA damage and reversed Man‐A‐inhibited tumor growth. However, the precise molecular details of how these reactive oxygen species (ROS) influence cell signaling modules are poorly understood. We examined how ROS may modulate death and survival pathways in a panel of tumor cells. Man‐A treatment resulted in a massive induction of superoxide anion (·O2−) only in Man‐A‐sensitive tumors. Within 1 hr, Man‐A caused the ROS‐dependent activation of caspases 9 and 3. In this time‐frame, the Ras‐Raf target, MEK, and the survival protein Akt were dephosphorylated in ROS‐dependent fashions and then cleaved in ROS and caspase‐dependent manners. Pretreatment with ROS scavengers blocked the adverse effects of Man‐A, including the processing of caspases and the cleavage of MEK and Akt. These events were noted before any losses in Ras activity or changes in its maturation could be detected. Finally, transfection with cDNAs encoding the antioxidant enzymes catalase, superoxide dismutase and thioredoxin reductase inhibited superoxide induction and apoptosis. Together, our data suggest that the elimination of tumors by Man‐A can be independent of the inhibiting of Ras. However, one universal feature observed is the generation of death‐triggering intracellular oxidants that appear to directly participate in the select targeting of growth and survival proteins that then either augment or ensure tumor cell death. © 2007 Wiley‐Liss, Inc.
Trends in childhood acute lymphoblastic leukemia in Western Australia, 1960–2006
Authors: Milne Elizabeth , Laurvick Crystal L , de Klerk Nicholas , Robertson Laila , Thompson Judith R. , Bower Carol 
Published: November 2007

AbstractIncreases in the incidence of childhood acute lymphoblastic leukemia (ALL) have been reported in some countries, while other reports from similar geographical regions have indicated stable rates. The reasons for the discrepancies have been debated in the literature, with the focus on whether the observed increases are “real” or an artifact resulting from improvements in diagnosis, case ascertainment and population coverage over time. We used population‐based data from Western Australia to investigate trends in the incidence of childhood ALL between 1960 and 2006. Age‐standardized incidence rates (ASRs) and rate ratios (indicating annual percent change) were estimated using Poisson regression. Between 1960 and 2006, the ASR was 3.7 per 100,000 person‐years, with an annual percent increase of 0.40% (95% CI: −0.20, 1.00). Between 1982 and 2006, the ASR was 3.8, with an annual percent increase of 0.80% (95% CI = −0.70 to 2.30). This increased to 1.42% (95% CI: −0.30, 3.0) when a sensitivity analysis was undertaken to assess the effect of excluding the final 2 years of data. Annual increases of 3.7% (95% CI: −0.50, 8.00) among children aged 5–14 years, and of 3.10% (95% CI: 0.50, 5.70) in girls, were observed for this latter period. These results were supported by national Australian incidence data available for 1982–2003. There may have been a small increase in the incidence of ALL since 1982 among girls and older children, but an overall increase appears unlikely. No impact of folate supplementation or fortification is apparent. © 2007 Wiley‐Liss, Inc.
Bayesian counterfactual analysis of the sources of the great moderation
Authors: Kim Chang‐Jin , Morley James , Piger Jeremy 
Published: November 2007

AbstractWe use counterfactual experiments to investigate the sources of the large volatility reduction in US real GDP growth in the 1980s. Contrary to an existing literature that conducts counterfactual experiments based on classical estimation and point estimates, we consider Bayesian analysis that provides a straightforward measure of estimation uncertainty for the counterfactual quantity of interest. Using Blanchard and Quah's (1989) structural VAR model of output growth and the unemployment rate, we find strong statistical support for the idea that a counterfactual change in the size of structural shocks alone, with no corresponding change in the propagation of these shocks, would have produced the same overall volatility reduction as what actually occurred. Looking deeper, we find evidence that a counterfactual change in the size of aggregate supply shocks alone would have generated a larger volatility reduction than a counterfactual change in the size of aggregate demand shocks alone. We show that these results are consistent with a standard monetary VAR, for which counterfactual analysis also suggests the importance of shocks in generating the volatility reduction, but with the counterfactual change in monetary shocks alone generating a small reduction in volatility. Copyright © 2007 John Wiley & Sons, Ltd.
In vitro evaluation of electrospun nanofiber scaffolds for vascular graft application
Authors: Lee Sang Jin , Yoo James J. , Lim Grace J. , Atala Anthony , Stitzel Joel 
Published: November 2007

AbstractBlood vessels are diverse in size, mechanical and biochemical properties, cellular content, and ultrastructural organization depending on their location and specific function. Therefore, it is required to control the fabrication of vascular grafts for obtaining desirable characteristics of blood vessel substitutes. In this study we have fabricated various scaffolds using the electrospinning technique with blends of collagen, elastin, and several biodegradable polymers. Biocompatibility, dimensional stability in vitro and mechanical properties were evaluated. Materials were blended at a relative concentration by weight of 45% collagen, 15% elastin, and 40% synthetic polymer to mimic the ratio of collagen and elastin in native blood vessels. The fabricated scaffolds are composed of randomly oriented fibers with diameters ranging from 477 to 765 nm. The electrospun scaffolds are nontoxic, dimensionally stable in an in vitro culture environment, easily fabricated, and possess controlled mechanical properties that simulate the ultrastructure of native blood vessels. The present study suggests that the introduction of synthetic biodegradable polymers enabled tailoring of mechanical properties of vascular substitutes and improving compliance matching for vascular tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Callus formation and remodeling at titanium implants
Authors: Eriksson Cecilia , Ohlson Karin , Richter Katrin , Billerdahl Nicklas , Johansson Mattias , Nygren Håkan 
Published: November 2007

AbstractTitanium is biocompatible with bone tissue, and during the healing process bone makes intimate contact with the implant surface. Although much is known about the long‐term healing of implants, less is known about the callus formation at implants. In this study, the histology of bone healing was studied during the period between 4 and 14 days. Incisions were made in rat tibia. Some incisions were simply left to heal, while in others titanium discs were implanted. Smooth implants as well as implants with different porosities were used. After 4, 7, and 14 days of healing, the sites of bone incisions were retrieved, decalcified, sectioned, and stained. The aim was to compare normal fracture healing with implant healing and to see whether implant properties influenced the short‐term healing process. Similarities between fracture healing and implant healing were evident. In both cases, inflammation, soft and hard callus formation, and remodeling had taken place during the period investigated. Between 7 and 14 days substantial bone resorption occurred around the implants. While after 14 days the marrow was almost completely reconstituted during normal wound healing, at the implants a thin layer of bone remained in close contact with the surface. Results from bone–implant contact measurements indicate that the surface properties of the implants do not have a significant influence on the early bone formation, since there were no significant differences between the smooth surface and any of the porous surfaces. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Effect of 2‐methacryloyloxyethyl phosphorylcholine concentration on photo‐induced graft polymerization of polyethylene in reducing the wear of orthopaedic bearing surface
Authors: Kyomoto Masayuki , Moro Toru , Miyaji Fumiaki , Hashimoto Masami , Kawaguchi Hiroshi , Takatori Yoshio , Nakamura Kozo , Ishihara Kazuhiko 
Published: November 2007

AbstractPhoto‐induced graft polymerization of 2‐methacryloyloxyethyl phosphorylcholine (MPC) on cross‐linked polyethylene (CLPE) has been developed as a novel technology for reducing wear of orthopaedic bearings. In this study, the effect of MPC concentration on graft polymerization and the resultant properties of the grafted poly (MPC) layer have been investigated. The grafted poly (MPC) layer thickness increased with the MPC concentration in feed. The hip simulator wear test confirmed that CLPE‐g‐MPC cups exhibited minimal wear compared with untreated CLPE cups. Since MPC is a highly hydrophilic methacrylate, the water‐wettability of CLPE‐g‐MPC was greater than that of untreated CLPE due to the formation of a poly(MPC) nanometer‐scale layer. The CLPE‐g‐MPC orthopaedic bearing surface exhibited high lubricity, because of the present of the poly(MPC) layer even at a thickness of 10 nm. This layer is considered responsible for the improved wear resistance. Nanometer‐scale modification of CLPE with poly(MPC) is expected to significantly increase the durability of the orthopaedic bearings. Poly (MPC) layer thickness can be controlled by changing the MPC concentration in feed. In order to achieve nanometer‐scale modification of poly(MPC) in this manner, it is necessary to use a long photo‐irradiation time for the MPC graft polymerization system, which contains a high‐concentration monomer without its gelation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Double hydrophilic block copolymers PEO‐b‐PGA: Synthesis, application as potential drug carrier and drug release via pH‐sensitive linkage
Authors: Tang Xuezhi , Pan Cai‐Yuan 
Published: November 2007

AbstractA new type of double hydrophilic block copolymer, poly(ethylene oxide) (PEO)‐block‐poly(glycerol monoacrylate) (PGA) have been synthesized via atom transfer radical polymerization of solketal acrylate (SA) using PEO‐Br as macro‐initiator, and subsequent hydrolysis of the acetal‐protecting group in 1N HCl solution in THF. The polymerization is of a “living” nature and the copolymers with controlled molecular weight and narrow polydispersity (Mw/Mn = 1.01–1.03) were obtained. The complete hydrolysis of the acetal‐protecting group was verified by IR and NMR spectroscopies. A hydrophobic fluorescent compound, 1‐pyrenecarboxaldehyde, was used as a model drug, which was covalently bound to the PEO‐b‐PGA block copolymer via a pH‐sensitive acetal linkage. The kinetics of the pyrene release was studied in THF/aqueous buffers at pH 5.0 (close to pH in endosomes) and 7.4 (pH of blood plasma) by fluorescent spectroscopy. The pyrene was released much faster at pH 5.0 than that at pH 7.4. The micelle behavior in solutions at pH 5.0 and 7.4 was studied by dynamic light scattering. All results show that this double hydrophilic PEO‐b‐PGA is a promising candidate for potential application as drug carrier for those carbonyl‐containing hydrophobic drugs. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Regulation of vascular smooth muscle cells on poly(ethylene terephthalate) film by O‐carboxymethylchitosan surface immobilization
Authors: Zhu Ai‐Ping , Zhao Feng , Fang Ning 
Published: November 2007

AbstractSpecifying the chemical environment of cells is a well‐established method of controlling cellular behaviors. In this study, poly(ethylene terephthalate) (PET) film was selected as a typical biomaterial to detect the effects of chemical modifications on material surface in controlling cell behaviors. Natural biopolymer chitosan and its biocompatible derivative, O‐carboxymethylchitosan (OCMCS) were surface immobilized on PET, respectively, via argon plasma followed by graft copolymerization with acrylic acid (AAc), which was exploited to covalently couple PET with chitosan (CS) and OCMCS molecules. Smooth muscle cells (SMCs) displayed a surface‐dependent cell spreading and cytoskeletal organization. The cells spread with a more pronounced elongated spindle shape, smaller cell area, and lower cell shape index (CSI) on OCMCS‐modified PET surface than on PET, or the PAA and chitosan‐immobilized PET surfaces after 24 h of culture. Cell‐culture viability after 5 days showed that all the modified materials possessed good cell proliferation. Our results suggest that cell adhesion, morphology, and growth can be mediated not only by varying the functional groups, electric charge, and wettability of PET surface but also by the specific biological recognition elicited from the biomaterials. These findings strongly support the concept that the microenvironment significantly influences cell behavior, highlighting the importance of environmental material biochemistry in cell‐based tissue engineering schemes. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Comparative study of nanohydroxyapatite microspheres for medical applications
Authors: Mateus Alis Yovana Pataquiva , Barrias Cristina C. , Ribeiro Cristina , Ferraz Maria P. , Monteiro Fernando J. 
Published: November 2007

AbstractThis study concerns the preparation, physical, and in vitro characterization of two different types of hydroxyapatite (HA) microspheres, which are intended to be used as drug‐delivery systems and bone‐regeneration matrices. Hydroxyapatite nanoparticles (HA‐1 and HA‐2) were prepared using the chemical precipitation synthesis with H3PO4, Ca(OH)2, and a surfactant, SDS (sodium dodecyl sulfate), as starting reagents. The HA powders were dispersed in a sodium alginate solution, and spherical particles were obtained by droplet extrusion coupled with ionotropic gelation in the presence of Ca2+. These were subsequently sintered to produce HA‐1 and HA‐2 microspheres with a uniform size and interconnected microporosity. Both powders and microspheres were characterized using FTIR and X‐ray diffraction. Moreover, SEM and mercury intrusion porosimetry were used to analyze the microspheres, and TEM was used to analyze the powders. Results showed that pure HA and mixtures of HA/β‐TCP in the nanometer range and needlelike shape were obtained for HA‐1 and HA‐2 powders, respectively. Neutral Red, scanning electron microscopy and confocal microscopy were used to evaluate the behavior of osteoblastic‐like MG‐63 cells cultured on HA microspheres surfaces for 7 days. Results showed that good adhesion and proliferation of osteoblasts on the HA microspheres surface. Cells built bridges between adjacent microspheres, forming microspheres‐cells clusters in both types of materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Preparation of water‐insoluble albumin film possessing nonadherent surface for cells and ligand binding ability
Authors: Yamazoe Hironori , Tanabe Toshizumi 
Published: November 2007

AbstractSerum albumin is the most abundant protein in blood plasma. Albumin has the ability to bind to a wide variety of compounds including drugs, and cells as well as proteins do not attach to an albumin‐coated surface. These properties of albumin are attractive for biomaterials utilized in biomedical fields. In the present study, we aimed to prepare a water‐insoluble albumin film possessing suitable flexibility and native albumin characteristics, such as drug binding ability and resistance to cell adhesion. To confer the film with both water insolubility and flexibility without losing albumin characteristics, we searched a suitable condition for the cross‐linking of albumin. As a result, we found that a film having aimed properties could be obtained by conducting the cross‐linking reaction at room temperature for 24 h using 215 mM ethylene glycol diglycidyl ether. Mouse fibroblast L929 cells did not adhere on thus obtained film in a similar manner to a native albumin‐coated surface. In addition, the film could bind 2‐(4′‐hydroxyphenylazo)‐benzoic acid, a representative albumin binding dye, and gradually release it in a pH‐dependent manner. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Novel biochemical pathways of endoglin in vascular cell physiology
Authors: Bernabeu Carmelo , Conley Barbara A. , Vary Calvin P.H. 
Published: November 2007

AbstractThe broad role of the transforming growth factor beta (TGFβ) signaling pathway in vascular development, homeostasis, and repair is well appreciated. Endoglin is emerging as a novel, complex, and poorly understood regulatory component of the TGFβ receptor complex, whose importance is underscored by its recognition as the site of mutations causing hereditary hemorrhagic telangiectasia (HHT) [McAllister et al., 1994]. Extensive analyses of endoglin function in normal developmental mouse models [Bourdeau et al., 1999; Li et al., 1999; Arthur et al., 2000] and in HHT animal models [Bourdeau et al., 2000; Torsney et al., 2003] exemplify the importance of understanding endoglin's biochemical functions. However, novel mechanisms underlying the regulation of these pathways continue to emerge. These mechanisms include modification of TGFβ receptor signaling at the ligand and receptor activation level, direct effects of endoglin on cell adhesion and migration, and emerging roles for endoglin in the determination of stem cell fate and tissue patterning. The purpose of this review is to highlight the cellular and molecular studies that underscore the central role of endoglin in vascular development and disease. J. Cell. Biochem. 102: 1375–1388, 2007. © 2007 Wiley‐Liss, Inc.
Program‐like aging and mitochondria: Instead of random damage by free radicals
Authors: Blagosklonny Mikhail V. 
Published: November 2007

AbstractAs recently suggested, the target of rapamycin (TOR) pathway, rather than molecular damage by free radicals, drives aging and diseases of aging. But may mitochondria nevertheless contribute to aging? Here, I discuss aimless program‐like aging (versus altruistic program), conflict between the cell and mitochondria, cell murder (versus cell suicide) and the role of mitochondria in aging. In particular, life‐long selection among mitochondria may yield “selfish” (malignant) mitochondria resistant to autophagy. And TOR may create an intra‐cellular environment that is permissive for such selfish mitochondria. In theory, pharmacologic inhibitors of the TOR pathway may reverse accumulation of defective mitochondria, while also inhibiting the aging process. J. Cell. Biochem. 102: 1389–1399, 2007. © 2007 Wiley‐Liss, Inc.
NCAM‐induced intracellular signaling revisited
Authors: Ditlevsen Dorte Kornerup , Povlsen Gro Klitgaard , Berezin Vladimir , Bock Elisabeth 
Published: November 2007

AbstractThe neural cell adhesion molecule (NCAM) plays a crucial role in neuronal development, synaptic plasticity, and regeneration. NCAM works as “smart glue” that not only mediates cell–cell adhesion but also induces activation of a complex network of intracellular signaling cascades on homophilic or heterophilic binding. Stimulation of NCAM by homophilic interactions induces neuronal differentiation through activation of a number of signaling molecules, including the fibroblast growth factor receptor, non–receptor kinases Fyn and focal adhesion kinase, growth‐associated protein‐43, the mitogen‐activated protein kinase pathway, intracellular Ca2+, and protein kinases A, C, and G. This review presents and discusses the current knowledge in the area of NCAM signaling with a focus on the events involved in NCAM‐mediated neurite outgrowth. © 2007 Wiley‐Liss, Inc.
β‐Catenin and actin reorganization in HGF/SF response of ST14A cells
Authors: Soldati C. , Biagioni S. , Poiana G. , Augusti‐Tocco G. 
Published: November 2007

AbstractHepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic factor that activates proliferation, differentiation, and migration of various cell types. Its action is mediated by c‐Met, a receptor endowed with tyrosine kinase activity that activates complex signaling cascades and mediates diverse cell responses. Although HGF action was first demonstrated in epithelial cells, expression of HGF and c‐Met receptor has also been described in developing and adult mammalian brain. In the developing central nervous system, areas of HGF and c‐Met expression are coincident with the migratory pathway of precursor cells. In the present article we report that the interaction between c‐Met and HGF/SF in striatal progenitor ST14A cells triggers a signaling cascade that induces modification of cell morphology, with decreased cell–cell interactions and increased cell motility; in particular, we analyzed the reorganization of the actin cytoskeleton and the delocalization of β‐catenin and N‐cadherin. The testing of other neurotrophic factors (NGF, BDNF, NT3, and CNTF) showed that the observed modifications were peculiar to HGF. We show that phosphoinositide 3‐kinase inhibitor treatment, which blocks cell scattering induced by HGF/SF, does not abolish actin and β‐catenin redistribution. The effects of HGF/SF on primary spinal cord cell cultures were also investigated, and HGF/SF was found to have a possible motogenic effect on these cells. The data reported suggest that HGF could play a role in the early steps of neurogenesis as a motogenic factor. © 2007 Wiley‐Liss, Inc.