bluuebunny/crossref_metadata_2025_split huggingface dataset:
Apathy and depression in Alzheimer's disease are associated with functional deficit and psychotropic prescription
Authors: Benoit M. , Andrieu S. , Lechowski L. , Gillette‐Guyonnet S. , Robert P. H. , Vellas B. 
Published: October 2007

AbstractBackgroundApathy and depression are the most common neuropsychiatric features in Alzheimer's disease (AD). The clinical and functional specific correlates of these syndromes are not well known independently from cognitive deficits and other behavioral disturbances.Material and methodsSix hundred and eighty‐six patients diagnosed with possible or probable AD were included in a prospective multicenter study (REAL‐FR). They had an assessment of their cognitive and functional status. Neuropsychiatric symptoms were assessed with the Neuropsychiatric Inventory (NPI) and caregiver's burden was measured with Zarit's Burden Scale.ResultsA majority of patients at any stage of the disease presented with one or several behavioral and psychological disturbances. Apathy concerned 43% of patients and, with or without depression, was associated with more pronounced deficits in global cognition, everyday life and instrumental abilities, nutritional status and with a higher burden level. A high level of psychotropic prescription, especially with antidepressant, was observed in patients with apathy. In a multivariate analysis taking into account the cognitive and functional variables of AD, apathy and depression were the only significant predictors of psychotropic prescription.ConclusionSome negative neuropsychiatric symptoms such as apathy and depression have a specific relation with functional and therapeutic outcomes of AD, independently from cognitive status. Further studies are needed to establish if apathy represents a particularly severe phenotype of AD. Copyright © 2007 John Wiley & Sons, Ltd.
Supersaturation and evasion of CO2 and CH4 in surface waters at Mer Bleue peatland, Canada
Authors: Billett M. F. , Moore T. R. 
Published: October 2007

AbstractCarbon dioxide (CO2) and methane (CH4) concentrations and evasion rates were measured in surface waters draining Mer Bleue peatland (Ontario, Canada) between spring and autumn 2005. All sites exhibit a consistent pattern of supersaturation throughout the year, which is broadly related to hydrological and temperature changes between spring snowmelt and autumn freezing. Both measurements and estimates of CO2 and CH4 evasion from open water to the atmosphere suggest that parts of the catchment (including beaver dams) are significant degassing hot spots. We present data showing how vertical gaseous carbon fluxes compare with lateral carbon fluxes and make an initial estimate of the importance to the overall carbon budget of CO2 and CH4 evasion to the atmosphere from water surfaces at Mer Bleue. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid decrease of mass balance observed in the Xiao (Lesser) Dongkemadi Glacier, in the central Tibetan Plateau
Authors: Pu Jianchen , Yao Tandong , Yang Meixue , Tian Lide , Wang Ninlian , Ageta Yutaka , Fujita Koji 
Published: October 2007

AbstractThe mass balance of the Xiao (Lesser) Dongkemadi Glacier located in the Tanggula Mountains, of the central Qinghai‐Tibetan Plateau has been monitored since 1989. The results show that the mass balance of the glacier has recently shown a deficit trend, and that the glacial terminus was also retreating. Positive mass balance of the glacier was dominant during the period 1989–1993, and the accumulated mass balance reached 970 mm. However, negative mass balance of the glacier has occurred since 1994, except for the large positive mass balance year 1997. The mass balance was − 701 mm in 1998, an extremely negative glacier mass balance year. The equilibrium line altitude showed a significant increasing trend. The mass balance of the glacier has changed from a significantly positive mass balance to a strongly negative mass balance since 1994. Meteorological data suggest that the rapid decrease in the mass balance is related to summer season warming. Copyright © 2007 John Wiley & Sons, Ltd.
Spatio‐temporal distribution of near‐surface and root zone soil moisture at the catchment scale
Authors: Martinez C. , Hancock G. R. , Kalma J. D. , Wells T. 
Published: October 2007

AbstractSoil moisture is highly variable both spatially and temporally. It is widely recognized that improving the knowledge and understanding of soil moisture and the processes underpinning its spatial and temporal distribution is critical. This paper addresses the relationship between near‐surface and root zone soil moisture, the way in which they vary spatially and temporally, and the effect of sampling design for determining catchment scale soil moisture dynamics. In this study, catchment scale near‐surface (0–50 mm) and root zone (0–300 mm) soil moisture were monitored over a four‐week period. Measurements of near‐surface soil moisture were recorded at various resolutions, and near‐surface and root zone soil moisture data were also monitored continuously within a network of recording sensors. Catchment average near‐surface soil moisture derived from detailed spatial measurements and continuous observations at fixed points were found to be significantly correlated (r2 = 0·96; P = 0·0063; n = 4). Root zone soil moisture was also found to be highly correlated with catchment average near‐surface, continuously monitored (r2 = 0·81; P < 0·0001; n = 26) and with detailed spatial measurements of near‐surface soil moisture (r2 = 0·84). The weaker relationship observed between near‐surface and root zone soil moisture is considered to be caused by the different responses to rainfall and the different factors controlling soil moisture for the soil depths of 0–50 mm and 0–300 mm. Aspect is considered to be the main factor influencing the spatial and temporal distribution of near‐surface soil moisture, while topography and soil type are considered important for root zone soil moisture. The ability of a limited number of monitoring stations to provide accurate estimates of catchment scale average soil moisture for both near‐surface and root zone is thus demonstrated, as opposed to high resolution spatial measurements. Similarly, the use of near‐surface soil moisture measurements to obtain a reliable estimate of deeper soil moisture levels at the small catchment scale was demonstrated. Copyright © 2007 John Wiley & Sons, Ltd.
Groundwater discharge mechanism in semi‐arid regions and the role of evapotranspiration
Authors: Abdalla Osman A. E. 
Published: October 2007

AbstractThe present study examined groundwater recharge/discharge mechanisms in the regional Central Sudan Rift Basins (CSRB). Aquifers in CSRB constitute poorly sorted silisiclastics of sand, clay and gravels deposited in closed hydrologic systems of the Cretaceous–Pleistocene fluviolacustrine environments. CSRB are bounded to the north by the highlands of the Central African Shear Zone (CAZS) that represents the surface and groundwater divides. Sporadic recharge in the peripheries of the basins along the CASZ occurs subsequent to decadal and centennial storm events. Inflow from the Nile into the aquifers represents an additional source of recharge. Thus, groundwater resources cannot be labelled fossil nor can they be readily recharged. Closed hydrologic troughs located adjacent to the influent Nile system mark areas of main groundwater discharge characterized by lower hydraulic heads. This study has examined mechanisms that derive the discharge of the groundwater in these closed basins and concluded that only evapotranspirative discharge can provide a plausible explanation. Groundwater abstraction is mainly through deep‐rooted trees and effective evaporation. The increase of TDS along the flow indicates local recharge at the peripheries of basins and shows the influence of evaporation and rock/water interaction. The decline in groundwater level along a flow path was calculated using Darcy's law to estimate average recharge and evapotranspirative discharge, which are equal under natural equilibrium and make the only fluxes in CSRB. Steady‐state 2D flow modelling has demonstrated that an average recharge of 4–8 mm yr−1 and evapotranspirative discharge of 1–22 mm yr−1 will maintain natural equilibrium in CSRB. Sporadic storms provide recharge in the highlands to preserve the current hydraulic gradient and maintain aquifer dynamics. Simulated recharge from the Nile totals about 17·5 mm yr−1 and is therefore a significant contributor to the water balance. Copyright © 2007 John Wiley & Sons, Ltd.
Neural network time series prediction of environmental variables in a small upland headwater in NE Scotland
Authors: Aitkenhead M. J. , Cooper R. J. 
Published: October 2007

AbstractShort‐term prediction of environmental variables such as stream flow rate is useful to members of the general public and environmental scientists alike, providing the ability to predict environmental disasters or scientifically interesting events. Here, a neural‐network based method is presented, which is capable of providing advance flood warnings or the prediction of high stream flow events for research purposes in a small upland headwater in NE Scotland. This method relies on training from past time series data acquired in the field, and provides the ability to predict a range of hydrological and meteorological variables up to 24 h ahead using feedback of predicted values at time t as new inputs for the next time step t + 1. The system is rapid and effective, relies on standard neural network training methods, and has the potential to be implemented in a web‐based monitoring and prediction package. The model design could be implemented at any study site where time series data has been gathered, and is sufficiently flexible to accept whatever data is available. Copyright © 2007 John Wiley & Sons, Ltd.
Force microscopy imaging of individual protein molecules with sub‐pico Newton force sensitivity
Authors: Patil Shivprasad , Martinez Nicolas F. , Lozano Jose R. , Garcia Ricardo 
Published: October 2007

AbstractThe capability of atomic force microscopes (AFM) to generate atomic or nanoscale resolution images of surfaces has deeply transformed the study of materials. However, high resolution imaging of biological systems has proved more difficult than obtaining atomic resolution images of crystalline surfaces. In many cases, the forces exerted by the tip on the molecules (1–10 nN) either displace them laterally or break the noncovalent bonds that hold the biomolecules together. Here, we apply a force microscope concept based on the simultaneous excitation of the first two flexural modes of the cantilever. The coupling of the modes generated by the tip–molecule forces enables imaging under the application of forces (∼35 pN) which are smaller than those needed to break noncovalent bonds. With this instrument we have resolved the intramolecular structure of antibodies in monomer and pentameric forms. Furthermore, the instrument has a force sensitivity of 0.2 pN which enables the identification of compositional changes along the protein fragments. Copyright © 2007 John Wiley & Sons, Ltd.
Epitope mapping on bovine prion protein using chemical cross‐linking and mass spectrometry
Authors: Pimenova Tatiana , Nazabal Alexis , Roschitzki Bernd , Seebacher Jan , Rinner Oliver , Zenobi Renato 
Published: October 2007

AbstractAn analytical strategy for the analysis of antigen epitopes by chemical cross‐linking and mass spectrometry is demonstrated. The information of antigen peptides involved in the binding to an antibody can be obtained by monitoring the antigen peptides modified by a partially hydrolyzed cross‐linker in the absence and in the presence of an antibody. This approach was shown to be efficient for characterization of the epitope on bovine prion protein bPrP(25–241) specifically recognized by a monoclonal antibody, 3E7 (mAb3E7), with only a small amount of sample (200 picomoles) needed. After cross‐linking of the specific immuno complex, a matrix‐assisted laser desorption/ionization (MALDI) mass spectrometer equipped with an ion conversion dynode (ICD) high‐mass detector was used to optimize the amount of cross‐linked complex formed at 202 kDa before proteolytic digestion. To identify the cross‐linked peptides after proteolysis without ambiguity, isotope‐labeled cross‐linkers, disuccinimidyl suberate (DSS‐d0/d12) and disuccinimidyl glutarate (DSG‐d0/d6), together with high‐resolution Fourier transform ion‐cyclotron resonance mass spectrometry (FTICR‐MS) were used. As a result, a complete fading of the peak intensities corresponding to the peptides representing the epitope was observed when bPrP/mAb3E7 complexes were formed. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of DESI‐FTICR mass spectrometry—from ECD to accurate mass tissue analysis
Authors: Takats Zoltan , Kobliha Vaclav , Sevcik Karel , Novak Petr , Kruppa Gary , Lemr Karel , Havlicek Vladimir 
Published: October 2007

AbstractImplementation of desorption electrospray ionization (DESI) technique on a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is described. Desorption electrospray technique is capable of the direct investigation of natural samples without any need for sample preparation or chromatographic separation. Since the DESI mass spectra of natural samples are very complex owing to the lack of preseparation or cleanup, the ideal mass spectrometric analyzer for these applications is a high‐resolution instrument such as FTICR mass spectrometer. DESI was implemented by constructing an electronically controlled source framework comprising six linear moving stages and one rotating stage. A three‐dimensional linear stage was used to accommodate samples, while another 3D linear stage equipped with rotating stage was used as a spray mount. A modified electrosonic sprayer was used as a primary electrospray device. DESI‐FTICR setup was characterized with regard to geometrical, electrical and flow conditions using deposited peptide samples in range of 1–100 pmol gross deposited amount on glass and polymer surfaces. Optimized conditions enabled the routine acquisition of DESI‐MS spectra on the instrument at 130 000 resolution in the broadband mode and with comparable sensitivity to data reported in the literature. Since the main significance of DESI‐FTICR MS is the combination of intact tissue analysis, the capabilities of the technique were demonstrated by analyzing murine liver samples. Presence of lysophospholipids in the liver tissue was tentatively associated with the lipid metabolism taking place in liver. DESI‐FTICR is also a promising technique in the field of peptide analysis due to capability of top‐down sequencing using electron capture dissociation. As a proof‐of‐principle experiment, a small synthetic polypeptide containing 36 amino acids was ionized using DESI and was sequenced in the FTICR by means of ECD (electron capture dissociation) fragmentation. Spectra gave almost full sequence information in agreement with the known amino acid sequence of the species. Copyright © 2007 John Wiley & Sons, Ltd.
Large‐scale separation of salvianolic acid B from the Chinese medicinal plant Salvia miltiorrhiza by pH‐zone‐refining countercurrent chromatography
Authors: Wang Xiao , Geng Yanling , Li Fuwei , Liu Jianhua 
Published: October 2007

AbstractpH‐Zone‐refining countercurrent chromatography was successfully applied to the separation of salvianolic acid B from the Chinese medicinal plant, Salvia miltiorrhiza Bunge, using a multilayer coil planet centrifuge. A 2.0 g quantity of sample was separated using the following two‐phase solvent system: methyl tert‐butyl ether (MtBE)–water, 10 mM TFA in organic stationary phase and 10 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by HPLC and ESI‐MS. The separation yielded 572 mg of the main component of salvianolic acid B with a purity of 94.1%.
Capillary gas chromatographic analysis of pyrrolidinedithiocarbamate metal chelates
Authors: Laghari Abdul J. , Khuhawar Muhammad Y. , Zardari Liaquat A. 
Published: October 2007

AbstractPyrrolidinedithiocarbamate (PDTC) chelates of Zn(II), Cu(II), Ni(II), Co(III), Fe(III), Mn(II), Cr(III), and VO(II) were analysed by capillary GC on a DB‐1701 column (30 m×0.25 mm id) with flame ionisation detection (FID). Linear calibrations were attained within “1–30 μg/mL” for Ni(II), Fe(III), Mn(II), Cr(III), Cu(II), and VO(II), and within “2–50 μg/mL” for Co(III) and Zn(II). The limits of detection were in the “150–500 ng/mL” range, corresponding to 15–50 pg amounts reaching the FID system. The optimised method was applied to the determination of Cu(II) and Ni(II) in coins, and that of Zn(II), Cu(II), Ni(II), Fe(III), Mn(II), Cr(III), and VO(II) in pharmaceutical preparations with relative standard deviations within 1.1–5.2%. The results obtained are in good agreement with sewage water samples and the declared values for the pharmaceutical formulations, or with the results of AAS of metal contents in coins, pharmaceutical preparations, and sewage water samples.
Development of a silica monolith microbioreactor entrapping highly activated lipase and an experiment toward integration with chromatographic separation of chiral esters
Authors: Kawakami Koei , Abe Daisuke , Urakawa Taiki , Kawashima Ayako , Oda Yasuhiro , Takahashi Ryo , Sakai Shinji 
Published: October 2007

AbstractMicrobioreactors are effective for high‐throughput production of expensive products from small amounts of substrates. Lipases are versatile enzymes for chiral syntheses, and are highly activated when immobilized in alkyl‐substituted silicates by the sol–gel method. For practical application of sol–gel immobilized lipases to a flow system, a microbioreactor loaded with a macroporous silica monolith is well suited, because it can be easily integrated with a chromatographic separator for optical resolution. We attempted to develop a microbioreactor containing a silica monolith‐immobilized lipase. A nonshrinkable silica monolith was first formed from a 4:1 mixture of methyltrimethoxysilane (MTMS) and tetramethoxysilane (TMOS). It was then coated with silica precipitates entrapping lipase, derived from a 4:1 mixture of n‐butyltrimethoxysilane (BTMS) and TMOS. As a result, monolith treated with the BTMS‐based silicate entrapping lipase exhibited approximately ten times higher activity than nontreated monolith‐immobilized lipase derived from the MTMS‐based silicate, in transesterification between glycidol and vinyl n‐butyrate in isooctane. A commercially available chiral column was connected in series to the monolith microbioreactor, and a pulse of substrate solution was supplied at the inlet of the reactor. Successful resolution of the racemic ester produced was achieved in the chromatographic column.
Specific capture of phosphopeptides by Zr4+‐modified monolithic capillary column
Authors: Dong Jing , Zhou Houjiang , Wu Renan , Ye Mingliang , Zou Hanfa 
Published: October 2007

AbstractA method to prepare zirconium phosphate (ZrP)‐modified monolithic capillary column for highly specific capture of phosphopeptides is presented. In this method, the phosphate monolithic capillary column was prepared by direct copolymerization of the functional monomer containing phosphate group (ethylene glycol methacrylate phosphate) and cross‐linker (bis‐acrylamide) in a ternary porogenic solvent. Copolymerization of cross‐linker and functional monomer simplifies the procedure for the preparation of phosphate chromatographic media. After Zr4+ was immobilized, the ZrP‐modified monolithic capillary column was evaluated by the analysis of standard phosphoproteins and the excellent selectivity of this approach was demonstrated by analyzing phosphopeptides in the digest mixture of β‐casein and BSA with molar ratio of 1:200.
Solvent hydrogen bonding and structural effects on nucleophilic substitution reactions: Part 3. Reaction of benzenesulfonyl chloride with anilines in benzene/propan‐2‐ol mixtures
Authors: Bhuvaneshwari D. S. , Elango K. P. 
Published: October 2007

AbstractSubstitution reactions of 13 para‐ and meta‐substituted anilines with benzenesulfonyl chloride in varying mole fractions of benzene in propan‐2‐ol have been investigated conductometrically. The second‐order rate constants correlate well with pKa values of anilines and with the Hammett's equation. The negative Hammett reaction constant indicates the formation of an electron‐deficient transition state. The rate data correlate satisfactorily with macroscopic solvent parameters such as relative permittivity, εr, and polarity, ETN. Correlation of rate data with Kamlet–Taft solvatochromic parameters (α, β, π*) suggests that both the specific and nonspecific solute–solvent interactions influence the reactivity. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 657–663, 2007
Solvent and structural effects on the kinetics of the reactions of 2‐substituted cyclohex‐1‐enylcarboxylic and 2‐substituted benzoic acids with diazodiphenylmethane
Authors: Nikolić J. B. , Ušćumlić G. S. , Juranić I. O. 
Published: October 2007

AbstractThe rate constants for the reaction of 2‐methyl‐cyclohex‐1‐enylcarboxylic, 2‐phenylcyclohex‐1‐enylcarboxylic, and 2‐methylbenzoic and 2‐phenylbenzoic acids with diazodiphenyl‐methane were determined in 14 various solvents at 30°C. To explain the kinetic results through solvent effects, the second‐order rate constants of the examined acids were correlated using the Kamlet–Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis, and the solvent effects on the reaction rates were analyzed in terms of initial and transition state contributions. The quantitative relationship between the molecular structure and the chemical reactivity has been discussed, as well as the effect of geometry on the reactivity of the examined molecules. The geometric data of all the examined compounds corresponding to the energy minima in solvent, simulated as dielectric continuum, obtained using semiempirical MNDO‐PM3 energy calculations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 664–671, 2007
Solvent effects on kinetics of the reaction between 2‐chloro‐3,5‐dinitropyridine and aniline in aqueous and alcoholic solutions of [bmim]BF4
Authors: Harifi‐Mood Ali Reza , Habibi‐Yangjeh Aziz , Gholami Mohammad Reza 
Published: October 2007

AbstractRate constants, kA, for the aromatic nucleophilic substitution reaction of 2‐chloro‐3,5‐dinitropyridine with aniline were determined in different compositions of 1‐(1‐butyl)‐3‐methylimidazolium terafluoroborate ([bmim]BF4) mixed with water, methanol, and ethanol at 25°C. The obtained rate constants of the reaction in pure solvents are in the following order: water > methanol > ethanol > [bmim]BF4. In these solutions, rate constants of the reaction decrease with the mole fraction of the ionic liquid. Single‐parameter correlations of log kA versus normalized polarity parameter (E), hydrogen bond acceptor basicity (β), hydrogen bond donor acidity (α), and dipolarity/polarizability (π*) do not give acceptable results in all solutions. Dual‐parameter correlations of log kA versus E and β also α and β gave reasonable results (e.g., in solutions of water with [bmim]BF4, the correlation coefficients are 0.994 and 0.996, respectively). The proposed dual‐parameter models demonstrate that the reaction rate constant increases with E, β, and α. The increase in the rate constant is attributed to hydrogen‐bonding interactions (donor and acceptor) of the media with an activated complex of the reaction that has the zwitterionic character. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 681–687, 2007