bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yukon River streamflow response to seasonal snow cover changes
Authors: Yang Daqing , Zhao Yuanyuan , Armstrong Richard , Robinson David 
Published: December 2008

AbstractWe used remotely sensed weekly snow water equivalent (SWE) and snow cover extent (SCE) data to investigate streamflow response to seasonal snowcover change over the Yukon watershed. We quantified the seasonal cycles and variations of snowcover (both SWE and SCE) and river streamflow, and identified a clear correspondence of river discharge to seasonal snowcover change. We also examined and compared the weekly mean streamflow with the weekly basin SWE and SCE. The results revealed a strong relation between the streamflow and snowcover change during the spring melt season. This relationship provides a practical procedure of using remotely sensed snowcover information for snowmelt runoff estimation over the large northern watersheds. Analyses of extreme (high/low) streamflow cases (years) and basin snowcover conditions indicate an association of high (low) flood peak with high (low) maximum SWE. Comparative analyses of weekly basin SWE versus SCE, peak snowmelt floods, and climatic variables (temperature and winter precipitation) indicate consistency among basin SWE, SCE, and temperature, but there is some incompatibility between basin SWE and winter precipitation. The inconsistency suggests uncertainties in determination of basin winter snowfall amounts and limitations in applications of the SWE retrieval algorithm over large watersheds/regions with different physical characteristics. Overall, the results of this study demonstrate that the weekly SWE and SCE data/products derived from remote sensing technology are useful in understanding seasonal streamflow changes in the northern regions. Copyright © 2008 John Wiley & Sons, Ltd.
Biocompatibility analysis of magnetic hydrogel nanocomposites based on poly(N‐isopropylacrylamide) and iron oxide
Authors: Meenach Samantha A. , Anderson A. Ashley , Suthar Mehul , Anderson Kimberly W. , Hilt J. Zach 
Published: December 2008

AbstractWith the growing interest in nanocomposites and their applications in biology and medicine, studies examining the biocompatibility of those materials are critical. Magnetic hydrogel nanocomposites based on poly(N‐isopropylacrylamide) and iron oxide nanoparticles were fabricated via UV‐polymerization with tetra(ethylene glycol) dimethacrylate acting as the crosslinking agent. In vitro biocompatibility analysis via NIH 3T3 murine fibroblast cytotoxicity was investigated. The fibroblasts in both direct and indirect contact with the hydrogels exhibited favorable cell viability indicating minimal cytotoxicity of the systems. In addition, swelling studies indicated that hydrogels with lower crosslink densities yield higher swelling ratios and that the presence of magnetic nanoparticle did not affect the swelling response of the hydrogel systems. Upon exposure to an alternating magnetic field, the hydrogel nanocomposites with iron oxide nanoparticles showed the capability for remote heating. This evaluation shows that these hydrogels have the potential to be used in biomedical applications such as drug delivery and hyperthermia for cancer treatment. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Intermittent watt‐level ultrasonication facilitates vancomycin release from therapeutic acrylic bone cement
Authors: Cai Xun‐Zi , Chen Xian‐Zhen , Yan Shi‐Gui , Ruan Zou‐Rong , Yan Rui‐Jian , Ji Kang , Xu Jia 
Published: December 2008

AbstractUltrasound holds promise for enhancing the vancomycin release from cement though the length of time when local drug level exceeded the minimum inhibitory concentration (T>MIC) was not prolonged by the previous protocol of milliwatt‐level ultrasonication. Here vancomycin‐loaded cements were subjected to continuous watt‐level ultrasonication (CUG), intermittent watt‐level ultrasonication (IUG) or no ultrasonication (NUG) for 14 d during immersion in 40‐ml phosphate buffered saline (PBS) for 28 d. The T>MIC for IUG was more than three times that for NUG. In contrast, T>MIC for CUG was slightly shortened. The subtherapeutic release of vancomycin between 15 d and 28 d for IUG was one‐ninth that for NUG. The fitting equations indicated a significant enhancement on the burst release and the slow release for IUG; however, the continuous ultrasonication hampered the slow release. SEM images exhibited denser craters and pores with larger diameters and less residual drug in specimens from IUG relative to those from both CUG and NUG. Intermittent watt‐level ultrasonication improved the ultrasound‐enhanced vancomycin release from cement in view of the prolonged T>MIC and the inhibited subtherapeutic release compared with continuous ultrasonication. The mechanisms may be associated with the distinctive effects of detaching forces and pushing forces by acoustic microstreams. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Mechanically enhanced microcapsules for cellular gene therapy
Authors: Shen F. , Mazumder M. A. J. , Burke N. A. D. , Stöver H. D. H. , Potter M. A. 
Published: December 2008

AbstractMicrocapsules bearing a covalently cross‐linked coating have been developed for cellular gene therapy as an improvement on alginate‐poly(L‐lysine)‐alginate (APA) microcapsules that only have ionic cross‐linking. In this study, two mutually reactive polyelectrolytes, a polycation (designated C70), poly([2‐(methacryloyloxy)ethyl]trimethylammonium chloride‐co‐2‐aminoethyl methacrylate hydrochloride) and a polyanion (designated A70), poly(sodium methacrylate‐co‐2‐(methacryloyloxy)ethyl acetoacetate), were used during the microcapsule fabrication. Ca‐alginate beads were sequentially laminated with C70, A70, poly(L‐lysine) (PLL), and alginate. The A70 reacts with both C70 and PLL to form a ∼30 μm thick covalently cross‐linked interpenetrating polymer network on the surface of the capsules. Confocal images confirmed the location of the C70/A70/PLL network and the stability of the network after 4 weeks implantation in mice. The mechanical and chemical resistance of the capsules was tested with a “stress test” where microcapsules were gently shaken in 0.003% EDTA for 15 min. APA capsules disappeared during this treatment, whereas the modified capsules, even those that had been retrieved from mice after 4‐weeks implantation, remained intact. Analysis of solutions passing through model flat membranes showed that the molecular weight cut‐off of alginate‐C70‐A70‐PLL‐alginate is similar to that of alginate‐PLL‐alginate. Recombinant cells encapsulated in APA and modified capsules were able to secrete luciferase into culture media. The modified capsules were found to capture some components of regular culture media used during preparation, causing an immune reaction in implanted mice, but use of UltraCulture serum‐free medium was found to prevent this immune reaction. In vivo biocompatibility of the new capsules was similar to the APA capsules, with no sign of clinical toxicity on complete blood counts and liver function tests. The increased stability of the covalently modified microcapsules coupled with the acceptable biocompatibility and permeability demonstrated their potential for use as immunoisolation devices in gene therapy. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Influence of ionization on the conformational preferences of peptide models. Ramachandran surfaces of N‐formyl‐glycine amide and N‐formyl‐alanine amide radical cations
Authors: Gil Adrià , Sodupe Mariona , Bertran Juan 
Published: December 2008

AbstractRamachandran maps of neutral and ionized HCO–Gly–NH2 and HCO–Ala–NH2 peptide models have been built at the B3LYP/6‐31++G(d,p) level of calculation. Direct optimizations using B3LYP and the recently developed MPWB1K functional have also been carried out, as well as single‐point calculations at the CCSD(T) level of theory with the 6‐311++G(2df,2p) basis set. Results indicate that for both peptide models ionization can cause drastic changes in the shape of the PES in such a way that highly disallowed regions in neutral PES become low‐energy regions in the radical cation surface. The structures localized in such regions, $ \varepsilon^{+\bullet}_{\rm L} $ and $ \varepsilon^{+\bullet}_{\rm D} $ are highly stabilized due to the formation of 2‐centre‐3‐electron interactions between the two carbonyl oxygens. Inclusion of solvent effects by the conductor‐like polarizable continuum model (CPCM) shows that the solute‐solvent interaction energy plays an important role in determining the stability order. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Interactions of the “piano‐stool” [ruthenium(II) (η6‐arene)(en)CL]+complexes with water and nucleobases; ab initio and DFT study
Authors: Futera Zdeněk , Klenko Julia , Šponer Judit E. , Šponer Jiří , Burda Jaroslav V. 
Published: December 2008

AbstractPiano stool ruthenium complexes of the composition [Ru(II)(η6‐arene)(en)Cl]+/2+(en = ethylenediamine) represent an emerging class of cisplatin‐analogue anticancer drug candidates. In this study, we use computational quantum chemistry to characterize the structure, stability and reactivity of these compounds. All these structures were optimized at DFT(B3LYP)/6‐31G(d) level and their single point properties were determined by the MP2/6‐31++G(2df,2pd) method. Thermodynamic parameters and rate constants were determined for the aquation process, as a replacement of the initial chloro ligand by water and subsequent exchange reaction of aqua ligand by nucleobases. The computations were carried out at several levels of DFT and ab initio theories (B3LYP, MP2 and CCSD) utilizing a range of bases sets (from 6‐31G(d) to aug‐cc‐pVQZ). Excellent agreement with experimental results for aquation process was obtained at the CCSD level and reasonable match was achieved also with the B3LYP/6‐31++G(2df,2pd) method. This level was used also for nucleobase‐water exchange reaction where a smaller rate constant for guanine exchange was found in comparison with adenine. Although adenine follows a simple replacement mechanism, guanine complex passes by a two‐step mechanism. At first, Ru‐O6(G) adduct is formed, which is transformed through a chelate TS2 to the Ru‐N7(G) final complex. In case of guanine, the exchange reaction is more favorable thermodynamically (releasing in total by about 8 kcal/mol) but according to our results, the rate constant for guanine substitution is slightly smaller than the analogous constant in adenine case when reaction course from local minimum is considered. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Extensive theoretical studies of a new energetic material: Tetrazino‐tetrazine‐tetraoxide (TTTO)
Authors: Song Xinli , Li Jicun , Hou Hua , Wang Baoshan 
Published: December 2008

Abstract[1,2,3,4]Tetrazino‐[5,6‐e]‐[1,2,3,4]tetrazine‐[1,3,5,7]tetraoxide (TTTO, C2N8O4) was suggested to be a possible candidate of high energy density materials (HEDM). The most stable conformation of TTTO is a planar structure with C2h symmetry. Using various high‐level ab initio methods including Gaussian‐n, Complete Basis Set, Full Coupled Cluster, and W1U models of chemistry together with density functional theory based models, the enthalpies of formation of TTTO at 0 K and standard state were calculated precisely. Moreover, the rovibrational and nuclear magnetic resonance properties were predicted as well. The solid state TTTO was studied using the crystal packing models with the Dreiding force‐filed and the plane‐wave periodic local‐density approximation density functional theory. Three stable polymorphous cells of TTTO have been found with either P212121 or P21/C symmetry. The high heat of formation (>200 kcal/mol), the high density (>2.0 g/cm3), the planar nonpolar electronic structure, and the perfect oxygen balance lead TTTO be a very promising HEDM with exceptional performance. This work provides the first theoretical support for further experimental synthesis and testing. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Molecular dynamics simulations of fluid methane properties using ab initio intermolecular interaction potentials
Authors: Chao Shih‐Wei , Li Arvin Huang‐Te , Chao Sheng D. 
Published: December 2008

AbstractIntermolecular interaction energy data for the methane dimer have been calculated at a spectroscopic accuracy and employed to construct an ab initio potential energy surface (PES) for molecular dynamics (MD) simulations of fluid methane properties. The full potential curves of the methane dimer at 12 symmetric conformations were calculated by the supermolecule counterpoise‐corrected second‐order Møller‐Plesset (MP2) perturbation theory. Single‐point coupled cluster with single and double and perturbative triple excitations [CCSD(T)] calculations were also carried out to calibrate the MP2 potentials. We employed Pople's medium size basis sets [up to 6‐311++G(3df, 3pd)] and Dunning's correlation consistent basis sets (cc‐pVXZ and aug‐cc‐pVXZ, X = D, T, Q). For each conformer, the intermolecular carbon–carbon separation was sampled in a step 0.1 Å for a range of 3–9 Å, resulting in a total of 732 configuration points calculated. The MP2 binding curves display significant anisotropy with respect to the relative orientations of the dimer. The potential curves at the complete basis set (CBS) limit were estimated using well‐established analytical extrapolation schemes. A 4‐site potential model with sites located at the hydrogen atoms was used to fit the ab initio potential data. This model stems from a hydrogen–hydrogen repulsion mechanism to explain the stability of the dimer structure. MD simulations using the ab initio PES show quantitative agreements on both the atom‐wise radial distribution functions and the self‐diffusion coefficients over a wide range of experimental conditions. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Expression of proinflammatory cytokines by human mesenchymal stem cells in response to cyclic tensile strain
Authors: Sumanasinghe Ruwan D. , Pfeiler T. Wayne , Monteiro‐Riviere Nancy A. , Loboa Elizabeth G. 
Published: December 2008

AbstractMesenchymal stem cells produce proinflammatory cytokines during their normal growth. Direct or indirect regulation of bone resorption by these cytokines has been reported. However, the effects of osteogenic conditions—chemical and/or mechanical—utilized during in vitro bone tissue engineering on expression of cytokines by hMSCs have not been studied. In this study, we investigated the effects of cyclic tensile strain, culture medium (with and without dexamethasone), and culture duration on the expression of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and interleukin‐8 (IL‐8) by bone marrow derived human mesenchymal stem cells (hMSCs). Human MSCs seeded in three‐dimensional Type I collagen matrices were subjected to 0%, 10%, and 12% uniaxial cyclic tensile strains at 1 Hz for 4 h/day for 7 and 14 days in complete growth or dexamethasone‐containing osteogenic medium. Viability of hMSCs was maintained irrespective of strain level and media conditions. Expression of either TNF‐α or IL‐1β was not observed in hMSCs under any of the conditions investigated in this study. Expression of IL‐6 was dependent on culture medium. An increase in IL‐6 expression was caused by both 10% and 12% strain levels. Both 10% and 12% strain levels caused an increase in IL‐8 production by hMSCs that was dependent on the presence of dexamethasone. IL‐6 and IL‐8 expressions by hMSCs were induced by cyclic tensile strain and osteogenic differentiating media, indicating that IL‐6 and IL‐8 may be functioning as autocrine signals during osteogenic differentiation of hMSCs. J. Cell. Physiol. 219: 77–83, 2009. © 2008 Wiley‐Liss, Inc.
Novel recombinant adenovirus type 41 vector and its biological properties
Authors: Lu Zhuo‐Zhuang , Zou Xiao‐Hui , Dong Liu‐Xin , Qu Jian‐Guo , Song Jing‐Dong , Wang Min , Guo Li , Hung Tao 
Published: December 2008

AbstractBackgroundHuman adenovirus serotype 41 (Ad41) is a natural pathogen of the digestive tract and can cause gastroenteritis. There has been interest in reconstructing Ad41 as a gene delivery vector targeting the gastrointestinal tract, which is hampered by its fastidiousness.MethodsAn Ad41 E1B55K‐transduced 293 cell line (293E12) was established as the packaging cell line. A backbone plasmid (pAdbone41) and a shuttle plasmid (pSh41‐CMV) were constructed based on the Ad41 genome. Replication‐defective adenovirus (Ad41‐GFP) was rescued in 293E12 after being transfected with the linearized adenoviral plasmid, which was generated by homologous recombination of pAdbone41 and the shuttle plasmid carrying the GFP gene in Escherichia coli strain BJ5183. The packaging ability of 293E12, the stability of the Ad41‐GFP genome and the acid‐resistant property of Ad41‐GFP were all investigated.ResultsA 293E12 cell could produce approximately 9000 viral particles of Ad41‐GFP, which is close to the amount in the control virus (Ad5‐GFP) amplified in one 293 cell. Ad41‐GFP contained a genetically stable genome after being passaged eight times in 293E12 cells. More significantly, Ad41‐GFP was more resistant to acid exposure than Ad5‐GFP. It retained almost complete viability when exposed to hydrochloric acid with a pH value of 2 for 30 min, whereas Ad5‐GFP lost 99% of its viability under the same conditions. Ad41‐GFP was also more tolerant to treatment with artificial digestive fluid.ConclusionsAn Ad41 vector system was successfully constructed, which consisted of the backbone plasmid, shuttle plasmid and packaging cell line 293E12. This system can be utilized to generate genetically stable and acid‐resistant recombinant Ad41 carrying any gene of interest. Copyright © 2008 John Wiley & Sons, Ltd.
Short hairpin RNAs against eotaxin or interleukin‐5 decrease airway eosinophilia and hyper‐responsiveness in a murine model of asthma
Authors: Huang Hsin‐Ying , Lee Chen‐Chen , Chiang Bor‐Luen 
Published: December 2008

AbstractBackgroundEosinophilia plays the major role in the pathogenesis of asthma and correlates with the up‐regulation of eotaxin, which, together with interleukin (IL)‐5, is important for differentiation, chemo‐attraction, degranulation, and survival of eosinophils in local tissue. In a previous study, we found that administration of lentivirus‐delivered short hairpin RNA (shRNA) to suppress the expression of IL‐5 inhibited airway inflammation. The present study aimed to investigate the role of eotaxin shRNA and the synergistic effect of eotaxin and IL‐5 shRNAs on airway inflammation in an ovalbumin (OVA)‐induced murine model of asthma.MethodsLentivirus‐delivered shRNAs were used to suppress the expression of eotaxin and/or IL‐5 in local tissue in an OVA‐induced murine asthma model.ResultsIntra‐tracheal administration of lentivirus containing eotaxin shRNA expressing cassette (eoSEC3.3) efficiently moderated the characteristics of asthma, including airway hyper‐responsiveness, cellular infiltration of lung tissues, and eotaxin and IL‐5 levels in bronchio‐alveolar lavage fluid. Administration of lentiviruses expressing IL‐5 or eotaxin shRNAs (IL5SEC4 + eoSEC3.3) also moderated the symptoms of asthma in a mouse model.ConclusionsLocal delivery of lentiviruses expressing IL‐5 and eotaxin shRNAs provides a potential tool in moderating airway inflammation and also has the potential for developing clinical therapy based on the application of shRNAs of chemokines and cytokines involved in T helper 2 cell inflammation and eosinophilia. Copyright © 2008 John Wiley & Sons, Ltd.
Downscaled GCM projections of winter and summer mass balance for Peyto Glacier, Alberta, Canada (2000–2100) from ensemble simulations with ECHAM5‐MPIOM
Authors: Matulla Christoph , Watson Emma , Wagner Sebastian , Schöner Wolfgang 
Published: December 2008

AbstractWe apply a direct downscaling approach to generate ensembles of local‐scale glacier mass balance projections from coarse‐scale general circulation model (GCM) data. The general modes of the atmospheric circulation over a large geographical region are linked statistically to Peyto Glacier's winter and summer balance separately. Our study focuses on the generation of ensemble projections derived from simulations with ECHAM5‐MPIOM forced with Intergovernmental Panel on Climate Change ‐ Special Report on Emission Scenarios (IPCC‐SRES) A1B and B1. The resulting ensembles of mass balance projections show a moderate increase in winter balance and a steep decrease in summer balance. Together these results suggest continued frontal recession and downwasting of Peyto Glacier and a shift of the equilibrium line altitude by at least 100 m above that estimated for the 1966–2001 period suggesting that very little of the glacier will remain by 2100. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Detection of urban warming in recent temperature trends in Japan
Authors: Fujibe Fumiaki 
Published: December 2008

AbstractThe contribution of urban effects on recent temperature trends in Japan was analysed using data at 561 stations for 27 years (March 1979–February 2006). Stations were categorized according to the population density of surrounding few kilometres. There is a warming trend of 0.3–0.4 °C/decade even for stations with low population density (<100 people per square kilometre), indicating that the recent temperature increase is largely contributed by background climatic change. On the other hand, anomalous warming trend is detected for stations with larger population density. Even for only weakly populated sites with population density of 100–300/km2, there is an anomalous trend of 0.03–0.05 °C/decade. This fact suggests that urban warming is detectable not only at large cities but also at slightly urbanized sites in Japan. Copyright © 2008 Royal Meteorological Society
Climate change impact on SWAT simulated streamflow in western Kenya
Authors: Githui Faith , Gitau Wilson , Mutua Francis , Bauwens Willy 
Published: December 2008

AbstractWeather and climate extremes such as droughts and floods have far reaching impacts in Kenya. They have had implications in a variety of sectors including agriculture, water resources, health, energy, and disaster management among others. Lake Victoria and its catchment support millions of people and any impact on its ability to support the livelihoods of the communities in this region is of major concern. Thus, the main objective of this study was to assess the potential future climatic changes on the Nzoia catchment in the Lake Victoria basin, and how they might affect streamflow. The Soil and Water Assessment Tool was used to investigate the impact of climatic change on streamflow of the study area. The model was set up using readily available spatial and temporal data, and calibrated against measured daily streamflow. Climate change scenarios were obtained from general circulation models.Results obtained showed increased amounts of annual rainfall for all the scenarios but with variations on a monthly basis. All—but one—global circulation models (GCMs) showed consistency in the monthly rainfall amounts. Rainfall was higher in the 2050s than in the 2020s. According to climate change scenarios, temperature will increase in this region, with the 2050s experiencing much higher increases than the 2020s with a monthly temperature change range of 0–1.7 °C. The range of change in mean annual rainfall of 2.4–23.2% corresponded to a change in streamflow of about 6–115%. The analysis revealed important rainfall–runoff linear relationships for certain months that could be extrapolated to estimate amounts of streamflow under various scenarios of change in rainfall. Streamflow response was not sensitive to changes in temperature. If all other variables, e.g. land cover, population growth etc., were held constant, a significant increase in streamflow may be expected in the coming decades as a consequence of increased rainfall amounts. Copyright © 2008 Royal Meteorological Society