bluuebunny/crossref_metadata_2025_split huggingface dataset:
A BTOP model to extend TOPMODEL for distributed hydrological simulation of large basins
Authors: Takeuchi Kuniyoshi , Hapuarachchi Prasantha , Zhou Maichun , Ishidaira Hiroshi , Magome Jun 
Published: November 2007

AbstractTopography is a dominant factor in hillslope hydrology. TOPMODEL, which uses a topographical index derived from a simplified steady state assumption of mass balance and empirical equations of motion over a hillslope, has many advantages in this respect. Its use has been demonstrated in many small basins (catchment areas of the order of 2–500 km2) but not in large basins (catchment areas of the order of 10 000–100 000 km2). The objective of this paper is to introduce the Block‐wise TOPMODEL (BTOP) as an extension of the TOPMODEL concept in a grid based framework for distributed hydrological simulation of large river basins. This extension was made by redefining the topographical index by using an effective contributing area af(a) (0⩽f(a)⩽1) per unit grid cell area instead of the upstream catchment area per unit contour length and introducing a concept of mean groundwater travel distance. Further the transmissivity parameter T0 was replaced by a groundwater dischargeability D which can provide a link between hill slope hydrology and macro hydrology. The BTOP model uses all the original TOPMODEL equations in their basic form. The BTOP model has been used as the core hydrological module of an integrated distributed hydrological model YHyM with advanced modules of precipitation, evapotranspiration, flow routing etc. Although the model has been successfully applied to many catchments around the world since 1999, there has not been a comprehensive theoretical basis presented in such applications. In this paper, an attempt is made to address this issue highlighted with an example application using the Mekong basin. Copyright © 2007 John Wiley & Sons, Ltd.
Oscillating peat surface levels in a restiad peatland, New Zealand—magnitude and spatiotemporal variability
Authors: Fritz Christian , Campbell David I. , Schipper Louis A. 
Published: November 2007

AbstractHydrology, particularly the water table position below the surface (relative water level, RWL), is an important control on biogeochemical and ecological processes in peatlands. The surface elevation (SE) in a peatland oscillates in response to changes in effective stress on the peat matrix mainly caused by water level fluctuations. This phenomenon is called peatland surface oscillation (PSO). To investigate the spatiotemporal variability of PSO, surface elevation and the water level above sea level (AWL) were measured monthly (23 sites) over one year in a warm‐temperate restiad peatland, New Zealand. At one site peat surface elevation was measured indirectly by monitoring AWL and RWL continuously with pressure transducers. Annual PSO (the difference between maximum and minimum surface elevation) ranged from 3·2 to 28 cm (mean = 14·9 cm). Surface elevation changes were caused by AWL fluctuations. Spatially homogenous AWL fluctuations (mean 40 cm among sites) translated into RWL fluctuations reduced 27–56% by PSO except for three sites with shallow and dense peat at the peatland margin (7–17%). The SE‐AWL relationship was linear for 15 sites. However, eight sites showed significantly higher rates of surface elevation changes during the wet season and thus a non‐linear behaviour. We suggest flotation of upper peat layers during the wet season causing this non‐linear behaviour. Surprisingly, PSO was subjected to hysteresis: the positive SE‐AWL relationship reversed after rainfall when the surface slowly rose despite rapidly receding AWL. Hysteresis was more prominent during the dry season than during the wet season. Total peat thickness and bulk density together could only explain 50% of the spatial variability of PSO based on manual measurements. However, we found three broad types of SE‐AWL relationships differing in shape and slope of SE‐AWL curves. These oscillation types reflected patterns in vegetation and flooding. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of boric acid and borax on titanium dioxide genotoxicity
Authors: Turkez Hasan 
Published: November 2007

AbstractTitanium dioxide (TiO2) is a potential carcinogenic/mutagenic agent although it is used in many areas including medical industries and cosmetics. Boron (as boric acid and borax) has also well‐described biological effects and therapeutic benefits. In a previous study, sister‐chromatid exchanges (SCEs) and micronuclei (MN) rates were assessed in control and TiO2‐treated (1, 2, 3, 5, 7.5 and 10 µm) human whole blood cultures. The results showed that the rates of SCE (at 2, 3, 5, 7.5 and 10 µm) and MN (at 5, 7.5 and 10 µm) formation in peripheral lymphocytes were increased significantly by TiO2 compared with the controls. The present study also investigated the genetic effects of boric acid and borax (2.5, 5 and 10 µm) on cultures with and without TiO2 addition. No significant increase in SCE and MN frequencies were observed at all concentrations of boron compounds. However, TiO2‐induced SCE and MN could be reduced significantly by the presence of boric acid and borax. In conclusion, this study indicated for the first time that boric acid and borax led to an increased resistance of DNA to damage induced by TiO2. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of zearalenone and α‐zearalenol toxicity on boar sperm DNA integrity
Authors: Tsakmakidis Ioannis A. , Lymberopoulos Aristoteles G. , Khalifa Tarek A. A. , Boscos Constanten M. , Saratsi Aikaterini , Alexopoulos Costas 
Published: November 2007

AbstractThis study aimed at investigating the in vitro effects of zearalenone (zen) and α‐zearalenol (α‐zen) on motility and nuclear chromatin integrity (NCI) of boar spermatozoa. Mycotoxins were tested, at levels ranging from 10 to 30 µg ml−1 of diluted semen. Four boars were used for semen collection (eight replicates per boar, four per mycotoxin). After the addition of zen or α‐zen, semen samples were incubated for 4 h at 38.5 °C, 5% CO2 and 96% humidified air. Motility and NCI were assessed at 0 and 4 h of incubation. No significant differences were noticed in motility among the experimental groups (P > 0.05) for all tested boars. Chromatin instability was significantly higher (P < 0.05) in spermatozoa of only one boar treated with zen and α‐zen independently of the dose. In conclusion, under our experimental conditions, zen and α‐zen did not affect the motility of boar sperm, whereas the effects of these toxins on sperm NCI were individual‐dependent. Copyright © 2007 John Wiley & Sons, Ltd.
Neither human hephaestin nor ceruloplasmin forms a stable complex with transferrin
Authors: Hudson David M. , Krisinger Michael J. , Griffiths Tanya A.M. , MacGillivray Ross T.A. 
Published: November 2007

AbstractIron homeostasis is essential for maintaining the physiological requirement for iron while preventing iron overload. Cell toxicity is caused by the generation of hydroxyl‐free radicals that result from redox reactions involving Fe(II). Multicopper ferroxidases regulate the oxidation of Fe(II) to Fe(III), circumventing the generation of these harmful by‐products. Ceruloplasmin (Cp) is the major multicopper ferroxidase in blood; however, hephaestin (Hp), a membrane‐bound Cp homolog, was recently discovered and has been implicated in the export of iron from duodenal enterocytes into blood. In the intracellular milieu, it is likely that iron exists as reduced Fe(II), yet transferrin (Tf), the plasma iron transporter, is only capable of binding oxidized Fe(III). Due to the insoluble and reactive nature of free Fe(III), the oxidation of Fe(II) upon exiting the duodenal enterocyte may require an interaction between a ferroxidase and the iron transporter. As such, it has been suggested that as a means of preventing the release of unbound Fe(III), a direct protein–protein interaction may occur between Tf and Hp during intestinal iron export. In the present study, the putative interaction between Tf and both Cp and a soluble form of recombinant human Hp was investigated. Utilizing native polyacrylamide gel electrophoresis, covalent cross‐linking and surface plasmon resonance (SPR), a stable interaction between the two proteins was not detected. We conclude that a stable complex between these ferroxidases and Tf does not occur under the experimental conditions used. We suggest alternative models for loading Tf with Fe(III) during intestinal iron export. J. Cell. Biochem. 103: 1849–1855, 2007. © 2007 Wiley‐Liss, Inc.
Regulation of Fgf10 gene expression in murine mesenchymal cells
Authors: Jean Jyh‐Chang , Lü Jining , Joyce‐Brady Martin , Cardoso Wellington V. 
Published: November 2007

AbstractFgf10 has a prominent role in organogenesis. In the developing lung, Fgf10 is dynamically expressed in the distal mesenchyme from where it diffuses and activates its epithelial receptor, Fgfr2b, to trigger budding. Little is known about how Fgf10 expression is regulated. Here we have identified a mouse lung‐specific mesenchymal cell line, MLg, which expresses endogenous Fgf10 and responds to known regulators of Fgf10 in a way that is reminiscent of the early lung. To gain insights into the mechanisms involved in the transcriptional regulation of Fgf10 in these cells, we have cloned and analyzed approximately a 4.5 kb region of the mouse Fgf10 promoter. Promoter deletion analysis and Luciferase reporter assays revealed an upstream region of the Fgf10 promoter with selective enhancer activity in the MLg, but not in the non‐lung‐derived cell line NIH3T3. Our data suggest that a potential lung mesenchyme‐specific enhancer may exist within this region of the Fgf10 promoter. J. Cell. Biochem. 103: 1886–1894, 2007. © 2007 Wiley‐Liss, Inc.
Functional expression of organic anion transporters in hepatic organoids reconstructed by rat small hepatocytes
Authors: Oshima Hideki , Kon Junko , Ooe Hidekazu , Hirata Koichi , Mitaka Toshihiro 
Published: November 2007

AbstractSmall hepatocytes (SHs) are hepatic progenitor cells with hepatic characteristics. They can proliferate to form colonies in culture and change their morphology from flat to rising/piled‐up with bile canaliculi (BC), which results in maturation. In this study, we examined whether SHs could express hepatic transporters with polarity, whether the transporters could transport organic anion substrates into BC, and whether the secreted substances could be recovered from BC. Immunocytochemistry and RT‐PCR were carried out. [3H]‐labeled estrogen derivatives were used to measure the functions of the transporters in SHs isolated from normal and multidrug resistance‐associated protein (Mrp) 2‐deficient rats. The results showed that organic anion‐transporting proteins (Oatps) 1 and 2, Na+‐dependent taurocholate co‐transporting polypeptide (Ntcp), Mrp2, and bile‐salt export pump (Bsep) were well expressed in rising/piled‐up cells and that their expression was correlated to that of hepatocyte nuclear factor 4α. Although small SHs expressed not Oatps and Mrp2 but Mrp3, rising/piled‐up SHs expressed Oatp1 and 2 and Mrp2 proteins in the sinusoidal and BC membranes, respectively. On the other hand, breast cancer resistant protein (Bcrp) and Mrp3 expression decreased as SHs matured. The substrate transported via Oatps and Mrp2 was secreted into BC and it accumulated in both BC and cyst‐like structures. The secreted substrate could be efficiently recovered from BC reconstructed by SHs derived from a normal rat, but not from an Mrp2‐deficient rat. In conclusion, SHs can reconstitute hepatic organoids expressing functional organic anion transporters in culture. This culture system may be useful to analyze the metabolism and excretion mechanisms of drugs. J. Cell. Biochem. 104: 68–81, 2008. © 2007 Wiley‐Liss, Inc.
A combined treatment of HeLa cells with the farnesyl protein transferase inhibitor L‐744,832 and cisplatin significantly increases the therapeutic effect as compared to cisplatin monotherapy
Authors: Węsierska‐Gądek Józefa , Kramer Matthias P. , Schmid Gerald 
Published: November 2007

AbstractActivating mutations of Ras that frequently occur during malignant transformation, enhance growth‐promoting signal transduction, allowing cells to bypass stringent control of cell cycle progression, thereby rendering them highly proliferative. Abundantly expressed c‐Ha‐ras protein in human cervical HeLa cells is farnesylated and attached to the plasma membrane, inducing enhanced signal transduction. Exposure of HeLa cells to cisplatin very efficiently inhibits cell proliferation and induces apoptosis. Unfortunately, high doses of cisplatin are strongly cytotoxic, therefore, an alternative therapeutic strategy allowing dose reduction of cisplatin by inhibition of farnesylation could increase the curative effects of cisplatin, thereby benefiting cancer patients. We used two inhibitors of farnesyl protein transferase (FPTase), FTI, and L‐744,832, to sensitize HeLa cells to the action of cisplatin. The combined administration of cisplatin and inhibitors of FPTase increased the cytostatic potency of cisplatin. L‐744,832 exhibited a stronger synergistic effect in combination with cisplatin than FTI. Moreover, the efficiency of the combined therapy strongly depended on the treatment regimen: The highest efficiency was achieved after combined treatment for 24 h and post‐incubation with an inhibitor of FPTase for 48 h. Following this optimized treatment, apoptosis was induced in approximately 50% of HeLa cells treated with 1 µM cisplatin, representing approximately a threefold increase as compared to cisplatin monotherapy. Combined treatment of HeLa cells with cisplatin and inhibitors of FPTase significantly increases the efficacy of the therapy and allows to reduce the dose of cisplatin. Importantly, best therapeutic effects can be achieved by post‐treatment with inhibitors of FPTase. J. Cell. Biochem. 104: 189–201, 2008. © 2007 Wiley‐Liss, Inc.
Strategies for an efficient implementation of the Gauss–Bessel quadrature for the evaluation of multicenter integral over STFs
Authors: Duret Stefan , Bouferguene Ahmed , Safouhi Hassan 
Published: November 2007

AbstractIn a previous work, a new Gauss quadrature was introduced with a view to evaluate multicenter integrals over Slater‐type functions efficiently. The complexity analysis of the new approach, carried out using the three‐center nuclear integral as a case study, has shown that for low‐order polynomials its efficiency is comparable to the SD. The latter was developed in connection with multi‐center integrals evaluated by means of the Fourier transform of B functions. In this work we investigate the numerical properties of the Gauss–Bessel quadrature and devise strategies for an efficient implementation of the numerical algorithms for the evaluation of multi‐center integrals in the framework of the Gaussian transform/Gauss–Bessel approach. The success of these strategies are essential to elaborate a fast and reliable algorithm for the evaluation of multi‐center integrals over STFs. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Molecular mechanisms of p21 and p27 induction by 3‐methylcholanthrene, an aryl‐hydrocarbon receptor agonist, involved in antiproliferation of human umbilical vascular endothelial cells
Authors: Pang Pai‐Huei , Lin Ying‐Hsi , Lee Yi‐Hsuan , Hou Hsing‐Han , Hsu Sung‐Po , Juan Shu‐Hui 
Published: November 2007

AbstractWe previously reported that 3‐methylcholanthrene (3MC), an aryl‐hydrocarbon receptor (AhR) agonist, inhibits the proliferation of human umbilical vascular endothelial cells (HUVECs; Juan et al., 2006, Eur J Pharmacol 530: 1–8). Herein, pretreatment of HUVECs with p21 or p27 small interfering (si)RNA reduced 3MC‐induced elimination of [3H]thymidine incorporation, demonstrating their essential roles in the antiproliferation of HUVECs. The molecular mechanisms of p21 and p27 involved in the antiproliferative effects of 3MC were elucidated in this study. 3MC time‐ and concentration‐dependently increased p21 and p27 levels, and decreased the protein level of CDK2 with no apparent alteration of p53. Interestingly, 3MC‐mediated p21 and p27 inductions were eliminated by resveratrol, an AhR antagonist, suggesting their AhR dependency, further confirmed by AhR siRNA. Among the relevant pathways, p38MAPK activation sustained the levels of p21 and p27 induced by 3MC, which was eliminated by AhR antagonists and N‐acetylcysteine (NAC), an antioxidant. 3MC concentration‐dependently enhanced not only the consensus dioxin‐responsive element (DRE)‐driven luciferase activity, but also the binding activity of the AhR to the putative DRE derived from the p21 and p27 promoters. A deletion of the DRE (−285/−270) in p21 (−2,300/+8) only partially alleviated the 3MC‐induced luciferase activity unless NAC was added, suggesting that there may be a DRE‐independent mechanism associated with oxidative stress. However, a deletion of the DRE (−660/−645) in p27 (−1,358/−100) almost completely abrogated the activation. Our study demonstrated that both the functional DRE and the phosphorylation of p38MAPK are essential for the induction of p21 and p27, resulting in the antiproliferative action of 3MC in HUVECs. J. Cell. Physiol. 215: 161–171, 2008. © 2007 Wiley‐Liss, Inc.
Immobilization of Pycnoporus sanguineus laccase by metal affinity adsorption on magnetic chelator particles
Authors: Wang Feng , Guo Chen , Liu Hui‐Zhou , Liu Chun‐Zhao 
Published: November 2007

AbstractBACKGROUND: Immobilized enzymes provide many advantages over free enzymes including repeated or continuous reuse, easy separation of the product from reaction media, easy recovery of the enzyme, and improvement in enzyme stability. In order to improve catalytic activity of laccase and increase its industrial application, there is great interest in developing novel technologies on laccase immobilization.RESULTS: Magnetic Cu2+‐chelated particles, prepared by cerium‐initiated graft polymerization of tentacle‐type polymer chains with iminodiacetic acid (IDA) as chelating ligand, were employed for Pycnoporus sanguineus laccase immobilization. The particles showed an obvious high adsorption capacity of laccase (94.1 mg g−1 support) with an activity recovery of 68.0% after immobilization. The laccase exhibited improved stability in reaction conditions over a broad temperature range between 45 °C and 70 °C and an optimal pH value of 3.0 after being adsorbed on the magnetic metal‐chelated particles. The value of the Michaelis constant (Km) of the immobilized laccase (1.597 mmol L−1) was higher than that of the free one (0.761 mmol L−1), whereas the maximum velocity (Vmax) was lower for the adsorbed laccase. Storage stability and temperature endurance of the immobilized laccase were found to increase greatly, and the immobilized laccase retained 87.8% of its initial activity after 10 successive batch reactions.CONCLUSION: The immobilized laccase not only can be operated magnetically, but also exhibits remarkably improved catalytic capacity and stability properties for various parameters, such as pH, temperature, reuse, and storage time, which can provide economic advantages for large‐scale biotechnological applications of laccase. Copyright © 2007 Society of Chemical Industry
Small cycle double covers of products I: Lexicographic product with paths and cycles
Authors: Nowakowski R. J. , Seyffarth K. 
Published: November 2007

AbstractBondy conjectured that every simple bridgeless graph has a small cycle double cover (SCDC). We show that this is the case for the lexicographic products of certain graphs and along the way for the Cartesian product as well. Specifically, if G does not have an isolated vertex then G □ P2 and G □ C2k have SCDCs. If G has an SCDC then so does G □ Pk, k > 2 and G □ C2k + 1. We use these Cartesian results to show that P2j[G] (j ≥ 1) and Ck[G] (k ≠ 3, 5, 7) have SCDCs. Also, if G has an SCDC then so does P2j + 1[G] (j ≥ 4). The results for the lexicographic product are harder and, in addition to the Cartesian results, require certain decompositions of Kn,n into perfect matchings. © 2007 Wiley Periodicals, Inc. J Graph Theory 57: 99–123, 2008
Plaques in the descending aorta: A new risk factor for stroke? Visualization of potential embolization pathways by 4D MRI
Authors: Harloff Andreas , Strecker Christoph , Frydrychowicz Alex P. , Dudler Patrick , Hetzel Andreas , Geibel Annette , Kollum Marc , Weiller Cornelius , Hennig Jürgen , Markl Michael 
Published: November 2007

AbstractThe combination of morphologic and hemodynamic information can help in assessing the risk of embolic stroke associated with thrombi and plaques in the descending aorta. For two acute stroke patients, the determination of individual embolic pathways using flow‐sensitive four‐dimensional (4D) MRI are reported. 3D visualization of local flow patterns, i.e., retrograde flow channels originating at the site of the atheroma, in conjunction with exact plaque localization, suggested potential embolization of high‐risk plaques in the descending aorta although they are located downstream from the supraaortic arteries. Our findings indicate that taking plaques of the descending aorta into consideration may help improve the spectrum of pathologies considered as high‐risk sources for brain ischemia. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Diffusion‐weighted imaging of inflammatory myopathies: Polymyositis and dermatomyositis
Authors: Qi Jing , Olsen Nancy J. , Price Ronald R. , Winston Jason A. , Park Jane H. 
Published: November 2007

AbstractMuscles of myositis patients examined with MRI demonstrate heterogeneous pathology ranging from unaffected muscle groups to severe inflammation, fat infiltration, and eventually, more serious fat replacement. The purpose of this investigation was to characterize myositic thigh muscles using diffusion‐weighted imaging (DWI) and to examine fluid motion at various disease stages. We chose to characterize total fluid motion within the muscle using the model proposed by Le Bihan et al (6,7) in which the apparent diffusion coefficient (ADC), diffusion in the extra‐ and intracellular muscle compartments (D), perfusion in capillaries (pseudodiffusion) (D*), and volume fraction of capillary perfusion (f) are determined. Unaffected patient muscles have DWI coefficients equivalent to those of normal muscles. Inflamed muscles show elevated ADC and D values compared to normal muscles (P < 0.0005), and fat‐infiltrated muscles have lower values than control muscles (P < 0.001). Inflamed muscles have lower f values than unaffected muscles (P < 0.009), suggesting decreased fractional volume of capillary perfusion. DWI provides quantitative data on molecular fluid motion in diseased muscles and affords the potential for longitudinal monitoring of myositic patients. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
RP‐HPTLC densitometric determination and validation of vanillin and related phenolic compounds in accelerated solvent extract of Vanilla planifolia*
Authors: Sharma Upendra Kumar , Sharma Nandini , Gupta Ajai Prakash , Kumar Vinod , Kumar Sinha Arun 
Published: November 2007

AbstractA simple, fast and sensitive RP‐HPTLC method is developed for simultaneous quantitative determination of vanillin and related phenolic compounds in ethanolic extracts of Vanilla planifolia pods. In addition to this, the applicability of accelerated solvent extraction (ASE) as an alternative to microwave‐assisted extraction (MAE), ultrasound‐assisted extraction (UAE) and Soxhlet extraction was also explored for the rapid extraction of phenolic compounds in vanilla pods. Good separation was achieved on aluminium plates precoated with silica gel RP‐18 F254S in the mobile phase of methanol/water/isopropanol/acetic acid (30:65:2:3, by volume). The method showed good linearity, high precision and good recovery of compounds of interest. ASE showed good extraction efficiency in less time as compared to other techniques for all the phenolic compounds. The present method would be useful for analytical research and for routine analysis of vanilla extracts for their quality control.