bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling the probability of occurrence of shallow landslides and channelized debris flows using GEOtop‐FS
Authors: Simoni Silvia , Zanotti Fabrizio , Bertoldi Giacomo , Rigon Riccardo 
Published: October 2007

AbstractThis paper describes a coupled, distributed, hydrological‐geotechnical model, GEOtop‐FS, which simulates the probability of occurrence of shallow landslides and debris flows. We use a hydrological distributed model, GEOtop, which, models latent and sensible heat fluxes and surface runoff, and computes soil moisture in 3‐D by solving Richards'equation numerically, together with an infinite‐slope geotechnical model, GEOtop‐FS. The combined model allows both the hydraulic and geotechnical properties of soil to be considered and realistically modelled. In particular, the model has been conceived to make direct use of field surveys, geotechnical characteristics and soil moisture measurements. In the model the depth of available sediments is also used to characterize the hydraulic properties of the area examined.To account for the uncertainty related to the natural variability in the factors influencing the stability of natural slopes, the safety factor is computed with a probabilistic approach. In order to determine the likelihood of slope failures, soil parameters are assigned distributions instead of single deterministic values.The analysis presented was carried out for an alpine watershed, located in the Friuli region, Italy, for which some geological and geotechnical data were available. In the past, this watershed experienced landslides and debris flows during intense storms following long and moderate intensity rainfall events. The distributed coupled GEOtop‐FS model was calibrated by reproducing some of these events and validated in order to map future failure probabilities. Copyright © 2007 John Wiley & Sons, Ltd.
Vulnerability of water resources, vegetation productivity and soil erosion to climate change in Mediterranean watersheds
Authors: Nunes João Pedro , Seixas Júlia , Pacheco Nuno Ricardo 
Published: October 2007

AbstractClimate change is expected to increase temperatures and lower rainfall in Mediterranean regions; however, there is a great degree of uncertainty as to the amount of change. This limits the prediction capacity of models to quantify impacts on water resources, vegetation productivity and erosion. This work circumvents this problem by analysing the sensitivity of these variables to varying degrees of temperature change (increased by up to 6·4 °C), rainfall (reduced by up to 40%) and atmospheric CO2 concentrations (increased by up to 100%). The SWAT watershed model was applied to 18 large watersheds in two contrasting regions of Portugal, one humid and one semi‐arid; incremental changes to climate variables were simulated using a stochastic weather generator. The main results indicate that water runoff, particularly subsurface runoff, is highly sensitive to these climate change trends (down by 80%). The biomass growth of most species showed a declining trend (wheat down by 40%), due to the negative impacts of increasing temperatures, dampened by higher CO2 concentrations. Mediterranean species, however, showed a positive response to milder degrees of climate change. Changes to erosion depended on the interactions between the decline in surface runoff (driving erosion rates downward) and biomass growth (driving erosion rates upward). For the milder rainfall changes, soil erosion showed a significant increasing trend in wheat fields (up to 150% in the humid watersheds), well above the recovery capacity of the soil. Overall, the results indicate a shift of the humid watersheds to acquire semi‐arid characteristics, such as more irregular river flows and increasingly marginal conditions for agricultural production. Copyright © 2007 John Wiley & Sons, Ltd.
Groundwater–surface water interactions, nutrient fluxes and ecological response in river corridors: Translating science into effective environmental management
Authors: Smith J. W. N. , Bonell M. , Gibert J. , McDowell W. H. , Sudicky E. A. , Turner J. V. , Harris R. C. 
Published: October 2007

AbstractA summary is provided of the second in a series of Integrated Science Initiative workshops supported by the UNESCO International Hydrological Programme. The workshop brought together hydrologists, ecologists, biogeochemists, hydrogeologists and natural resource managers to discuss the processes that occur in hyporheic and riparian ecotones. The principal objectives were to share new ideas on the importance of biogeochemical processes that affect nutrients at the groundwater–surface water interface, to understand the impact of nutrient flux on stream (principally hyporheic) ecology, and to identify the management strategies for river corridors to mitigate the effects of nutrients applied to land and discharged via groundwater into rivers. The workshop concluded that: (1) more interdisciplinary research and environmental management practices are needed to better understand, predict and manage processes at the interface of environmental compartments; (2) the goal of environmental regulations to improve ecological health requires a holistic approach integrating our understanding of the ecological, hydrological, biogeochemical and physical processes; (3) upscaling spatially and temporally variable processes remains difficult and may hinder translation of research at micro‐scales (molecular to grain size) into macro‐scale (reach to catchment) decision‐making; (4) scientists need to better communicate existing research to river managers, while smanagers must better communicate policy and regulatory‐driven science requirements to researchers. Existing models, such as those that simulate stream–hyporheic exchange, are not widely known and rarely used by environmental managers. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of carboxyamidotriazole on in vitro models of imatinib‐resistant chronic myeloid leukemia
Authors: Alessandro Riccardo , Fontana Simona , Giordano Margherita , Corrado Chiara , Colomba Paolo , Flugy Anna Maria , Santoro Alessandra , Kohn Elise C. , De Leo Giacomo 
Published: October 2007

AbstractAlthough imatinib mesylate (IM) has revolutionized the treatment of chronic myeloid leukemia (CML), some patients develop resistance with progression of leukemia. Alternative or additional targeting of signaling pathways deregulated in bcr‐abl‐driven CML cells may provide a feasible option for improving clinical response and overcoming resistance. In this study, we show that carboxyamidotriazole (CAI), an orally bioavailable calcium influx and signal transduction inhibitor, is equally effective in inhibiting the proliferation and bcr‐abl dependent‐ and independent‐signaling pathways in imatinib‐resistant CML cells. CAI inhibits phosphorylation of cellular proteins including STAT5 and CrkL at concentrations that induce apoptosis in IM‐resistant CML cells. The combination of imatinib and CAI also down‐regulated bcr‐abl protein levels. Since CAI is already available for clinical use, these results suggest that it may be an effective addition to the armamentarium of drugs for the treatment of CML. J. Cell. Physiol. 215: 111–121, 2008. © 2007 Wiley‐Liss, Inc.
Engineering a circularly permuted GFP scaffold for peptide presentation
Authors: Paschke Matthias , Tiede Christian , Höhne Wolfgang 
Published: October 2007

AbstractThe use of peptides as in vivo and in vitro ligand binding agents is hampered by the high flexibility, low stability and lack of intrinsic detection signal of peptide aptamers. Recent attempts to overcome these limitations included the integration of the binding peptide into a stable protein scaffold. In this paper, we present the optimization and testing of a circularly permuted variant of the green fluorescent protein (GFP). We examined the ability of the optimized scaffold to accept peptide insertions at three different regions. The three regions chosen are localized in close spatial proximity to each other and support different conformations of the inserted peptides. In all the three regions peptides with a biased, but still comprehensive, amino acid repertoire could be presented without disturbing the function of the optimized GFP‐scaffold. Copyright © 2007 John Wiley & Sons, Ltd.
Properties and molecular evolution of human GLUD2 (neural and testicular tissue‐specific) glutamate dehydrogenase
Authors: Kanavouras Konstantinos , Mastorodemos Vasileios , Borompokas Nikolas , Spanaki Cleanthe , Plaitakis Andreas 
Published: October 2007

AbstractGlutamate dehydrogenase (GDH) is an enzyme central to the metabolism of glutamate that also plays a role in cellular energetics. In the human, GDH exists in a housekeeping isoenzyme (hGDH1) encoded by the GLUD1 gene and a neural and testicular tissue‐specific isoform (hGDH2) encoded by the GLUD2 gene. There is evolutionary evidence that the GLUD1 was retroposed to the X chromosome in the ape ancestor (>23 million years ago), where it gave rise to GLUD2 through random mutations and directional selection. In the human, the two mature GDH isoproteins are highly homologous, differing in only 16 of their 505 amino acid residues. Functional analyses of highly purified recombinant wild‐type hGDH2 revealed that this adaptive evolution dissociated the enzyme from GTP control, permitted regulation almost entirely by ADP and/or L‐leucine, and fine‐tuned its activity to the relatively low cellular pH that occurs in synaptic astrocytes during excitatory transmission. Study of structure‐function relationships, using site‐directed mutagenesis of GLUD1 at single sites differing from GLUD2, showed that the Arg443Ser and the Gly456Ala change reproduced some, but not all, of the properties of hGDH2. In addition, we created a double hGDH1 mutant that had both Arg443Ser and Gly456Ala in the same polypeptide chain. Functional analyses revealed that the doubly mutated enzyme did not acquire all the characteristics of the wild‐type hGDH2. Hence, additional amino acid changes, acting in concert with Arg443Ser and Gly456Ala, ought to be responsible the unique properties of the brain‐specific human isoenzyme. © 2007 Wiley‐Liss, Inc.
Seasonality of modern pollen and sediment deposition in an estuarine context: the Severn Estuary Levels, southwest England
Authors: Allen J. R. L. , Dark Petra 
Published: October 2007

AbstractRecent sedimentological and palynological research on subfossil Holocene banded sediments from the Severn Estuary Levels suggested seasonality of deposition, registered by variations in mineral grain‐size and pollen assemblages between different parts of the bands. Here we provide data that strengthen this interpretation from sampling of modern sediments and pollen deposition on an active mudflat and saltmarsh on the margin of the Severn Estuary, and comparison with a vegetation survey and contemporary records of climate, river and tidal regimes. The results of grain‐size analysis indicate deposition of comparatively coarse‐grained silts during the relatively cool and windy conditions of winter and comparatively fine‐grained sediments during relatively warm and calm summer months. Pollen analysis demonstrates the significance of long‐term storage of pollen grains and fern spores in the estuarine waterbody, superimposed on which seasonal variations in pollen inputs from local and regional vegetation remain detectable. Copyright © 2007 John Wiley & Sons, Ltd.
Electrochromatographic separation on a poly(dimethylsiloxane)/glass chip by integration of a capillary containing an acrylate monolithic stationary phase
Authors: Blas Maximilien , Delaunay Nathalie , Rocca Jean‐Louis 
Published: October 2007

AbstractIn this paper, we present an approach to perform electrochromatographic separations on poly(dimethylsiloxane) chips: a fused‐silica capillary containing a stationary phase was introduced directly into the chip. This approach would offer great flexibility since capillary modification methods are well known, and thus, with this kind of chip, different microfluidic devices having various functionalizations could be prepared. Electrophoretic separations were first achieved by integrating an empty capillary into the chip to evaluate the analytical performances of this system. They were compared to those obtained with a classical chip. Finally, an electrochromatographic separation involving a capillary containing a hexyl acrylate‐based monolith was performed. These preliminary results show this approach to be promising.
Elementary reaction step model of the N‐nitrosation of ammonia
Authors: Silva Gabriel Da , Dlugogorski Bogdan Z. , Kennedy Eric M. 
Published: October 2007

AbstractThis contribution develops a comprehensive kinetic model of the N‐nitrosation reaction mechanism, consisting almost entirely of elementary reaction steps and applies it to study the nitrosation of ammonia. The reaction mechanism features 26 species and 22 reactions, with 8 parallel reaction pathways for ammonia nitrosation and a side pathway for nitrous acid decomposition. We compiled forward and reverse rate constants for each of the reactions, either from the literature sources or by correlation with known rate and equilibrium constants. The concentration of each reaction species with respect to time can be obtained for any set of initial concentrations by invoking a simultaneous solution to the system of ordinary differential equations describing the reaction mechanism. The model successfully predicts previous experimental results for ammonia nitrosation, with and without the addition of the catalyst thiocyanate. The effect of pH on the rate and mechanism of ammonia nitrosation was studied with the model. For uncatalyzed nitrosation, the results indicate that between pH 6.0 and 1.5 the reaction proceeds predominantly via reaction with N2O3, whereas ON+ nitrosation becomes the preferred pathway below pH 1.5. ONSCN is the dominant nitrosating agent across the entire pH range studied when the nucleophile thiocyanate was added in appreciable quantities. However, with the weak nucleophile Cl−, nitrosation by N2O3 and ON+ governed the reaction kinetics at high and low pH, respectively. We demonstrate that nitrosating agent formation is rapid and does not limit the rate of ammonia nitrosation; however, nitrosating agent formation could become the rate‐limiting step for the nitrosation of highly reactive substrates. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 645–656, 2007
Metallomicelle catalysis: Hydrolysis of p‐nitrophenyl picolinate induced by Schiff base Co(II) complexes in a Gemini surfactant micellar solution
Authors: Jiang Weidong , Xu Bin , Li Jianzhang , Lin Qi , Zeng Xiancheng , Chen Hua 
Published: October 2007

AbstractTwo Schiff base cobalt(II) complexes containing crowned substituents have been synthesized and employed to promote the hydrolysis of p‐nitrophenyl picolinate (PNPP) in a buffered micellar solution formed by a cationic Gemini surfactant, bis(hexadecyldimethylammonium)hexane bromide (G(hex)C16, 2Br−) over a pH range of 6.50–8.50. In comparison, the reactivity of PNPP hydrolysis catalyzed by the same catalysts in the other micellar system, formed by a conventional single‐chain analogue, that is, hexadecyltrimethylammonium bromide (CTAB), has also been evaluated under a selected condition. The results clearly reveal that the two metallomicelles made of the aforementioned Co(II) complexes and the G(hex)C16 are both efficient for catalyzing PNPP hydrolysis with about 3 orders of magnitude in rate acceleration compared with the background rate of PNPP spontaneous hydrolysis. Moreover, the rates of PNPP hydrolysis catalyzed by the two cobalt(II) complexes in G(hex)C16 micelles are about 2 times higher than in CTAB micelles, correspondingly. In addition, observations show that steric hindrance of substituents of the two complexes is also one of the major influencing factors in the PNPP hydrolytic reaction. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 672–680, 2007
A Novel Poly(4‐methyl‐2‐pentyne)/TiO2 Hybrid Nanocomposite Membrane for Natural Gas Conditioning: Butane/Methane Separation
Authors: Yave Wilfredo , Shishatskiy Sergey , Abetz Volker , Matson Samira , Litvinova Elena , Khotimskiy Valeriy , Peinemann Klaus‐Viktor 
Published: October 2007

AbstractPoly(4‐methyl‐2‐pentyne) (PMP)/TiO2 hybrid nanocomposite membranes have been investigated for natural gas conditioning. Tailor‐made PMP with 35% cis‐content was identified as an attractive material to prepare nanocomposite membranes; it presented good stability towards organic vapors and optimal properties for butane/methane separation. The PMP/TiO2 hybrid nanocomposite membranes presented an improvement of butane permeability and butane/methane selectivity. The addition of TiO2 nanoparticles to the PMP enhanced the selectivity more effectively than fumed‐silica, and it is attractively higher than those currently reported in the open literature.magnified image
Fabrication of Superhydrophobic and Superoleophilic Polystyrene Surfaces by a Facile One‐Step Method
Authors: Tu Cheng‐Wei , Tsai Chia‐Hua , Wang Chih‐Feng , Kuo Shiao‐Wei , Chang Feng‐Chih 
Published: October 2007

AbstractA facile one‐step method has been developed to prepare both superhydrophobic and superoleophilic surfaces of polystyrene (PS) without any chemical modification. A rough film consisting of micro‐bead and nano‐fiber mixed structures is formed by spraying a PS solution onto a large area and any type of substrate. The mixed structures with such unique wettability properties can be used in oil/water separation and as oil sorbents.magnified image
A Click Approach to Chiral‐Dendronized Polyfluorene Derivatives
Authors: Liu Zi‐Tong , He Yan‐Mei , Li Bao‐Lin , Liu Ji , Fan Qing‐Hua 
Published: October 2007

AbstractA new kind of chiral‐dendronized binaphthyl‐containing polyfluorene derivatives has been synthesized through “click chemistry” efficiently. The resulting copolymers exhibited desirable properties, such as excellent solubility, good thermal stability, and considerably high molecular weights. The photophysical properties of the copolymers were investigated in details, and the results indicated that the combination of chiral binaphthyl unit and bulky dendron could effectively suppress intermolecular packing and aggregation. In addition, the investigation of circular dichroism behavior of these chiral‐dendronized copolymers showed a strong Cotton effect at long wavelength (373–379 nm), indicating that the chirality of the binaphthyl units was transferred to the whole polyfluorene backbone.magnified image
Novel Anti‐Microbial Host‐Guest Complexes Based on Cationic β‐Cyclodextrin Polymers and Triclosan/Butylparaben
Authors: Guan Yong , Qian Liying , Xiao Huining 
Published: October 2007

AbstractThe preparation of novel cationic β‐cyclodextrin polymers (CPβCDs) and its complexes with butylparaben and triclosan were reported in this paper. FT‐IR and two‐dimensional (2D) 1H–1H gradient correlated spectroscopy (gCOSY) NMR spectra confirmed that the antibiotics could be included inside the lipophilic cavities of CPβCDs. The water solubility of the antibiotics was improved significantly after inclusion with CPβCDs. The results also suggest that it was easier for butylparaben, which had relatively small molecular size, to form the complexes with CPβCDs than triclosan. Due to the targeting effect after the inclusion with cationic CPβCDs, the anti‐microbial activity of butylparaben was also enhanced substantially. However, similar improvement was not obvious for triclosan.magnified image
Isolation and identification of metabolites from dihydromyricetin
Authors: Zhang Yansong , Que Sheng , Yang Xiuwei , Wang Bin , Qiao Liang , Zhao Yuying 
Published: October 2007

AbstractDihydromyricetin (DHM) is the major bioactive constituent of Rattan Tea, which is the tender stems and leaves of Ampelopsis grossendentata. Seven metabolites (2–8) of DHM (1) were obtained by the chromatographic method. The metabolites 2–5 were obtained from the urine of rats administered orally with DHM; and metabolites 6–8 were detected in the fecal specimens of rats, which were also produced by human intestinal bacteria (HIB) in vitro, and were separated from the cultured media of HIB containing DHM. Their structures were elucidated as 5,7,3′,5′‐tetrahydroxyflavanonol (2); 5,7,3′,5′‐tetrahydroxy‐4′‐methoxyflavanonol (3); 5,7,4′,5′‐tetrahydroxy‐3′‐methoxyflavanonol (4); and dihydromyricetin‐O‐5‐β‐D‐glucuronide (5); (2R,3S)‐5,7,3′,4′,5′‐pentahydroxyflavanonol (6); 3,4,5,7,3′,4′,5′‐hepthydroxyflavan (7) and 5,7,3′,4′,5′‐pentahydroxyflavanone (8) on the basis of UV, NMR and LC‐MS/MS data. These seven metabolites were formed through familiar metabolic reactions. Dihydromyricetin‐O‐5‐β‐D‐glucuronide (5) is a new compound. The 13C‐NMR data of (2) and (4) are reported for the first time. Copyright © 2007 John Wiley & Sons, Ltd.
Purity analysis of hydrogen cyanide, cyanogen chloride and phosgene by quantitative 13C NMR spectroscopy
Authors: Henderson Terry J. , Cullinan David B. 
Published: October 2007

AbstractHydrogen cyanide, cyanogen chloride and phosgene are produced in tremendously large quantities today by the chemical industry. The compounds are also particularly attractive to foreign states and terrorists seeking an inexpensive mass‐destruction capability. Along with contemporary warfare agents, therefore, the US Army evaluates protective equipment used by warfighters and domestic emergency responders against the compounds, and requires their certification at ≥ 95 carbon atom % before use. We have investigated the 13C spin‐lattice relaxation behavior of the compounds to develop a quantitative NMR method for characterizing chemical lots supplied to the Army. Behavior was assessed at 75 and 126 MHz for temperatures between 5 and 15 °C to hold the compounds in their liquid states, dramatically improving detection sensitivity. T1 values for cyanogen chloride and phosgene were somewhat comparable, ranging between 20 and 31 s. Hydrogen cyanide values were significantly shorter at 10–18 s, most likely because of a 1H13C dipolar contribution to relaxation not possible for the other compounds. The T1 measurements were used to derive relaxation delays for collecting the quantitative 13C data sets. At 126 MHz, only a single data acquisition with a cryogenic probehead gave a signal‐to‐noise ratio exceeding that necessary for certifying the compounds at ≥ 95 carbon atom % and 99% confidence. Data acquired at 75 MHz with a conventional probehead, however, required ≥ 5 acquisitions to reach this certifying signal‐to‐noise ratio for phosgene, and ≥ 12 acquisitions were required for the other compounds under these same conditions. In terms of accuracy and execution time, the NMR method rivals typical chromatographic methods. Published in 2007 by John Wiley & Sons, Ltd.
The 14N quadrupole coupling in hexamethylene triperoxide diamine (HMTD)
Authors: Persons John , Harbison Gerard S. 
Published: October 2007

AbstractUsing high‐field NMR, we have determined the magnitude of the nuclear quadrupole interaction in hexamethylene triperoxide diamine (HMTD), the explosive allegedly used in the London bombings of July 2005. The experimental quadrupolar coupling constant, 5.334 MHz, is in good agreement with quantum chemical calculations. The predicted single zero‐field transition frequency should lie in a relatively empty part of the 14N nuclear quadrupole resonance (NQR) spectrum; the spin relaxation rate is reasonably fast. Copyright © 2007 John Wiley & Sons, Ltd.