bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of glyoxal and methylglyoxal in the serum of diabetic patients by MEKC using stilbenediamine as derivatizing reagent
Authors: Mirza Muhammad A. , Kandhro Abdul J. , Memon Saima Q. , Khuhawar Muhammad Y. , Arain Rafee
Published: October 2007

An analytical method has been developed for the separation of glyoxal (Go), methylglyoxal (MGo), and dimethylglyoxal (DMGo) by MEKC using stilbenediamine (SD) as derivatizing reagent, separation time 6.5 min, SDS as micellar medium at pH 8, and sodium tetraborate (0.1 M) as buffer. Uncoated fused‐silica capillary, effective length 50 cm×75 μm id; applied voltage 20 kV and photodiode array detection, were used. Calibration was linear within 0.02–150 μg/mL with detection limits 3.5–5.8 ng/mL. Go and MGo, observed for diabetic and healthy volunteers, were within 0.098–0.193 μg/mL Go and 0.106–0.245 μg/mL MGo with RSD 1.6–3.5 and 1.7–3.4%, respectively, in diabetics against 0.016–0.046 μg/mL Go and 0.021–0.066 μg/mL MGo with RSDs 1.5–3.5 and 1.4–3.6%, respectively, in healthy volunteers. Go and MGo in diabetics were also measured by standard addition and DMGo as an internal standard. Additives do not contribute significantly to Go and MGo matrix.
Biofiltration of ethyl acetate under continuous and intermittent loading
Authors: Álvarez‐Hornos F. Javier , Gabaldón Carmen , Martínez‐Soria Vicente , Marzal Paula , Penya‐roja Josep‐Manuel , Sempere Feliu
Published: October 2007

A laboratory‐scale peat biofilter was used for ethyl acetate removal from an air stream over a period lasting 1 yr. In a first stage, the biofilter was operated under continuous mode: a maximum elimination capacity of 400 g m−3 h−1 was obtained, and ethyl acetate was efficiently degraded with empty bed residence time (EBRT) as short as 22 s. The estimated yield coefficient, determined from the carbon dioxide production, resulted in 0.42 g dry biomass produced per gram of ethyl acetate consumed. The living and the dead cell concentrations were also monitored. The dead cell percentages varied between 18 and 85%, progressive increases in the dead cell percentages were achieved as EBRT decreased and inlet load increased. In a second stage, operation under intermittent loading (16 h/day or 2‐h‐on/2‐h‐off cycles) was performed to investigate the effect of industrial practices such as overnight and weekend shutdowns, intermittent emission or inlet concentration and flow rate peaks. System performance was not significantly affected by changes, demonstrating the process viability for industrial applications. The intermittent loading of 16 h/day resulted in lower penetration of contaminant in the bed in comparison with continuous loading, but the 2‐h‐on/2‐h‐off caused a greater pollutant breakthrough detected at the first quarter of the biofilter, with a high increase in the dead cell density. Respirometric monitoring showed that biomass was fully activated in 1–2 h after night or weekend starvations. Finally, a 15 days starvation period was applied and afterwards operation was restarted. The system performance was fully restored without noticeable reacclimation period and dead cell density recovered normal values. © 2007 American Institute of Chemical Engineers Environ Prog, 2007
A contribution to the phylogeny of annual species of Astragalus (Fabaceae) in the Old World using hair micromorphology and other morphological characters
Authors: Taeb F. , Zarre S. , Podlech D. , Tillich H.‐J. , Kazempour Osaloo S. , Maassoumi A. A.
Published: October 2007

A cladistic analysis including 32 annual and nine perennial species of Astragalus along with four outgroups from related genera is performed using characters from hair micromorphology, floral morphology and some other morphological sources. The hair characters show the similar evolutionary trends as known earlier for the genus Astragalus, but they exhibit lower variability in comparison with other major subgroups of Astragalus. The obtained data was compared with the data from molecular systematics. The most important results of this study are: 1) medifixed hairs are developed at least two times among annual Astragalus, 2) fruit morphology, does not provide strong evidence in delimitation of the sections within annual Astragalus, 3) presence of long and thick hairs with largely tuberculate base should be considered as an advanced character, and can be regarded as an important synapomorphy among annual Astragalus, 4) the position of some species of the large and heterogeneous sect. Sesamei, e.g. A. persepolitanus and A. coronilla, and their possible close relationship with the species of the sect. Oxyglottis should be re‐assessed, 5) the species of the sect. Ankylotus show close relationship to sect. Platyglottis, based on floral morphology and hair characters, 6) there are not enough supports from hair, floral morphology and biogeography for considering A. annularis, A. epiglottis (as Glottis epiglottis), A. pelecinus (as Biserrula pelecinus) and A. vogelii (as Podlechiella vogelii) as separated from Astragalus (as suggested by molecular data). Moreover, the inclusion of Barnebyella calycina again in Astragalus is well supported by morphological data. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
K‐feldspar alteration to gel material and crystallization of glauconitic peloids with berthierine in Cretaceous marine sediments—sedimentary implications (Prebetic Zone, Betic Cordillera, SE Spain)
Authors: Jiménez‐Millán Juan , Castro José M.
Published: October 2007

Glauconitic peloids from a Hauterivian condensed level in a hemipelagic unit of the Internal Prebetic (Los Villares Formation, eastern Betic Cordillera) have been studied by X‐ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HRTEM) and analytical electron microscopy (AEM). The sediments forming the condensed level are characterized by abundant spherical to ovoid green glauconite peloids with radial cracks. Quartz, feldspar and muscovite are also abundant, whereas calcium phosphate is rarely detected. XRD analysis of the peloids reveals glauconite and small amounts of berthierine. SEM and HRTEM data show feldspar dissolution features, a Si–Al‐rich gel‐like substance filling K‐feldspar micropores and interlayering of well‐crystallized glauconite and berthierine packets. The last stage of the glauconitization process resulted in conversion of the smectitic precursor. Sedimentary and mineralogical features indicate an autochthonous origin for the glauconite. The depositional environment was a distal, hemipelagic ramp on the Southern Iberian Continental Palaeomargin. Low sedimentation rates lead to sediment condensation in a general transgressive context. The margin was affected by extensional tectonics, creating tilted blocks, resulting in lateral facies changes. The dissolution of K‐feldspars probably occurred after their deposition in the marine environment but predating the glauconitization. An influx of meteoric water is therefore required, probably related to subsurface fluxes from adjacent emergent areas (the higher parts of tilted blocks). Copyright © 2007 John Wiley & Sons, Ltd.
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

Background

Apathy 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 methods

Six 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.

Results

A 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.

Conclusion

Some 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

Carbon 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

The 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

Soil 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

The 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

Short‐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

The 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

An 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

Implementation 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

pH‐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

Pyrrolidinedithiocarbamate (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

Microbioreactors 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

A 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

Substitution 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

The 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

Rate 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
A kinetic study of the gas‐phase reactions of OIO with NO, NO2, and Cl2
Authors: Enami Shinichi , Hoshino Yosuke , Kawasaki Masahiro
Published: October 2007

The kinetics of iodine dioxide (OIO) reactions with nitric oxide (NO), nitrogen dioxide (NO2), and molecular chlorine (Cl2) are studied in the gas‐phase by cavity ring‐down spectroscopy. The absorption spectrum of OIO is monitored after the laser photodissociation, 266 or 355 nm, of the gaseous mixture, CH2I2/O2/N2, which generates OIO through a series of reactions. The second‐order rate constant of the reaction OIO + NO is determined to be (4.8 ± 0.9) × 10−12 cm3 molecule−1 s−1 under 30 Torr of N2 diluent at 298 K. We have also measured upper limits for the second‐order rate constants of OIO with NO2 and Cl2 to be k < 6 × 10−14 cm3 molecule−1 s−1 and k < 8 × 10−13 cm3 molecule−1 s−1, respectively. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 688–693, 2007
Synthesis and Characterization of Hyperbranched Polymers from the Polymerization of Glycidyl Methacrylate and Styrene Using Cp2TiCl as a Catalyst
Authors: Kong Li‐zhi , Pan Cai‐yuan
Published: October 2007

Hyperbranched poly(glycidyl methacrylate) (PGMA) and poly(GMA‐co‐styrene) have been synthesized by the self‐condensing vinyl polymerization of GMA and the copolymerization of GMA and St. Cp2Ti(III)Cl catalyzed the epoxy groups to produce initiating radicals and Cu(II)X2 (X = Br or Cl) was used for control of the polymerization. The resultant polymers were characterized by GPC and 1H NMR, and the molecular weights, the molecular weight distribution and the degree of branching were determined. The branching structure of the polymers was further confirmed by a hydrolysis test. Hyperbranched star polymers with HPGMA as the core and PSt as the arms were synthesized by the atom transfer radical polymerization of St using HPGMA as a macroinitiator. The resultant products were analyzed by GPC and 1H NMR. Their morphology in solution was investigated by TEM. The hyperbranched polymers were modified by various acids and amines, and the variation in solution properties was investigated.

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Macromol. Mater. Eng. 10–11/2007
Authors: de la Vega Oyervides A. , Ríos J. Bonilla , de Valle L. F. Ramos , de Almeida Prado L. A. S. , Schulte Karl
Published: October 2007

Cover: The picture depicts the mechanism of peroxide‐assisted coupling of isotatic poly(propylene) (iPP) and carbon nanofibers (CNFs), which, in turn, leads to improved adhesion between the filler (CNF) and the polymeric matrix (iPP) and increased stiffness of the matrix. Further details can be found in the article by A. de la Vega Oyervides, J. Bonilla Ríos,* L. F. Ramos de Valle, L. A. S. de Almeida Prado, and K. Schulte on page 1095.
Polymorphism Control of Poly(vinylidene fluoride) through Electrospinning
Authors: Zheng Jianfen , He Aihua , Li Junxing , Han Charles C.
Published: October 2007

Polymorphism control of PVDF has been realized through electrospinning. PVDF fibrous membranes with fiber diameter in the range of 100 nm to several micrometers were produced by electrospinning and the crystal phase of electrospun PVDF fibers can be adjusted at the same time. Through the control of electrospinning parameters such as the solvent, electrospinning temperature, feeding rate, and tip‐to‐collector distance, PVDF fibrous membranes containing mainly α‐ or β‐ or γ‐phase could be fabricated successfully.

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QQ‐HSQC: a quick, quantitative heteronuclear correlation experiment for NMR spectroscopy
Authors: Peterson Daniel J. , Loening Nikolaus M.
Published: October 2007

Quantitative heteronuclear single quantum coherence (Q‐HSQC) is a variant of the HSQC experiment that provides quantitative peak areas. This is accomplished by combining signals acquired using four different INEPT delays. Consequently, the experiment requires four times as many scans as the HSQC experiment to achieve the same resolution in the indirect dimension. We have removed this drawback by modifying the Q‐HSQC experiment so that signals corresponding to different INEPT delays are acquired simultaneously from different parts of the sample. This new experiment, which we call Quick, Quantitative HSQC (QQ‐HSQC), has the quantitative properties of the Q‐HSQC experiment but only requires as many scans as a conventional HSQC experiment. Copyright © 2007 John Wiley & Sons, Ltd.
The impact of the π‐electron conjugation on 15N, 13C and 1H NMR chemical shifts in push–pull benzothiazolium salts. Experimental and theoretical study
Authors: Hrobárik Peter , Horváth Branislav , Sigmundová Ivica , Zahradník Pavol , Malkina Olga L.
Published: October 2007

The 15N as well as 13C and 1H chemical shifts of eight push–pull benzothiazolium iodides with various π‐conjugated chains between dimethylamino group and benzothiazolium moiety have been determined by NMR spectroscopy at the natural‐abundance level of all nuclei in DMSO‐d6 solution. In general, the quaternary benzothiazolium nitrogen is more shielded [δ(15N‐3) vary between − 241.3 and − 201.9 ppm] with respect to parent 3‐methylbenzothiazolium iodide [δ(15N‐3) = − 183.8 ppm], depending on the length and constitution of the π‐conjugated bridge. A larger variation in 15N chemical shifts is observed on dimethylamino nitrogen, which covers the range of − 323.3 to − 257.2 ppm. The effect of π‐conjugation degree has a less pronounced influence on 13C and 1H chemical shifts.

Experimental data are interpreted by means of density functional theory (DFT) calculations. Reasonable agreement between theoretical and experimental 15N NMR chemical shifts was found, particularly when performing calculations with hybrid exchange‐correlation functionals. A better accord with experiment is achieved by utilizing a polarizable continuum model (PCM) along with an explicit treatment of hydrogen‐bonding between the solute and the water present in dimethylsulfoxide (DMSO). Finally, 13C and 1H NMR spectra were computed and analysed in order to compare them with available experimental data. Copyright © 2007 John Wiley & Sons, Ltd.
The role of aromatic groups in the Tobey–Simon additivity rule for vinylic protons
Authors: Shine Henry J. , Rangappa Paramashivappa
Published: October 2007

The Tobey–Simon (additivity) rule for aromatic groups which was devised about 40 years ago has been found to need revision. The rule shows an aromatic group attached to a CC double bond as causing a downfield chemical shift of a cis‐related vinylic proton and a small upfield shift of a trans‐related proton. A search of data in the recent literature has shown that this rule should apply mainly to monosubstituted phenyl groups and some polynuclear aromatics. In contrast with them, 2,6‐disubstituted phenyl, 2,4,6‐trisubstituted phenyl and 9‐anthracenyl groups cause cis‐related vinylic protons to resonate upfield of comparable trans‐related protons. Further, the current rule for o‐substituted phenyl groups has been found to be inaccurate. In writing a rule for aromatic groups, therefore, greater attention needs to be given to the diversity of effects that these groups have on chemical shifts of vinylic protons. Copyright © 2007 John Wiley & Sons, Ltd.
Spermatogenic cell‐specific type 1 hexokinase is the predominant hexokinase in sperm
Authors: Nakamura Noriko , Shibata Haruna , O'Brien Deborah A. , Mori Chisato , Eddy Edward M.
Published: October 2007

Hexokinase is the first enzyme in the glycolytic pathway and utilizes ATP to convert glucose to glucose‐6‐phosphate (G6P). We previously identified three variant transcripts of Hk1 that are expressed specifically in spermatogenic cells, have different 5′ untranslated regions, and encode a protein (HK1S, spermatogenic cell‐specific type 1 hexokinase) in which the porin‐binding domain (PBD) of HK1 is replaced by a novel N‐terminal spermatogenic cell‐specific region (SSR). However, the level of expression of the individual variant transcripts or of the other members of the hexokinase gene family (Hk2, Hk3, and Gck) in spermatogenic cells remains uncertain. We show that Hk1, Hk2, and Hk3 transcripts levels are quite low in spermatocytes and spermatids and Gck transcripts are relatively abundant in spermatids, but that glucokinase (GCK) is not detected in spermatozoa. Using real time RT‐PCR (qPCR) with primers specific for each of the three variant forms and RNA from whole testis and isolated germ cells, we found that transcripts for Hk1_v2 and Hk1_v3, but not for Hk1_v1, are relatively high in spermatids. Similar results were seen using spermatogenic cells isolated by laser‐capture microdissection (LCM). Immunoblotting studies found that HK1S is abundant in sperm, and immunostaining confirmed that HK1S is located mainly in the principal piece of the sperm flagellum, where other spermatogenic cell‐specific glycolytic enzymes have been found. These results strongly suggest that HK1, HK2, HK3, and GCK are unlikely to have a role in glycolysis in sperm and that HK1S encoded by Hk1_v2 and Hk1_v3 serves this role. Mol. Reprod. Dev. 75: 632–640, 2008. © 2007 Wiley‐Liss, Inc.
Correlation of urinary nerve growth factor level with pathogenesis of overactive bladder
Authors: Yokoyama Teruhiko , Kumon Hiromi , Nagai Atsushi
Published: October 2007

Aims

The origin of overactive bladder (OAB), which is a leading cause of lower urinary tract symptoms, remains unknown. Nerve growth factor (NGF) is one of the neurotrophic factors which are needed for the maintenance of sensory neurons. It is known that too much expression of NGF may induce bladder hyperactivity. In this study, we explored the correlation of the level of urinary NGF with various pathogenic OAB such as idiopathic, neurogenic OAB, and bladder outlet obstruction (BOO).

Methods

The study group included 51 OAB patients. Thirteen patients (7 females and 6 males) had idiopathic detrusor overactivity (DO) without BOO, 6 female idiopathic OAB without DO (sensory urgency), 16 patients with BOO due to BPH, and 16 patients with neurogenic DO (10 due to spinal cord injury (SCI), 6 due to cerebrovascular disease (CVD)). Thirty‐two patients who had normal cystometric findings (23 females and 9 males) without OAB symptoms were used as controls. Urinary NGF levels were measured by enzyme‐linked immunosorbent assay technique (ELISA) and the results were normalized based on creatinine (Cr) concentration.

Results

The urinary NGF levels in patients with neurogenic DO due to SCI, BOO, and sensory urgency were significantly higher compared with those of normal cystometric finding patients. However, the levels of urinary NGF were not statistically significant between patients with idiopathic DO without BOO, neurogenic DO due to CVD and patients with normal cystometric findings.

Conclusions

These data suggest that urinary NGF levels could serve as a basis for adjunct diagnosis of OAB. Neurourol. Urodynam. 27:417–420, 2008. © 2007 Wiley‐Liss, Inc.
Impact of field strength and iron oxide nanoparticle concentration on the linearity and diagnostic accuracy of off‐resonance imaging
Authors: Farrar Christian T. , Dai Guangping , Novikov Mikhail , Rosenzweig Anthony , Weissleder Ralph , Rosen Bruce R. , Sosnovik David E.
Published: October 2007

Off‐resonance imaging (ORI) techniques are being increasingly used to image iron oxide imaging agents such as monocrystalline iron oxide nanoparticles (MION). However, the diagnostic accuracy, linearity, and field dependence of ORI have not been fully characterized. In this study, the sensitivity, specificity, and linearity of ORI were thus examined as a function of both MION concentration and magnetic field strength (4.7 and 14 T). MION phantoms with and without an air interface as well as MION uptake in a mouse model of healing myocardial infarction were imaged. MION‐induced resonance shifts were shown to increase linearly with MION concentration. In contrast, the ORI signal/sensitivity was highly non‐linear, initially increasing with MION concentration until T2 became comparable to the TE and decreasing thereafter. The specificity of ORI to distinguish MION‐induced resonance shifts from on‐resonance water was found to decrease with increasing field because of the increased on‐resonance water linewidths (15 Hz at 4.7 T versus 45 Hz at 14 T). Large resonance shifts (∼300 Hz) were observed at air interfaces at 4.7 T, both in vitro and in vivo, and led to poor ORI specificity for MION concentrations less than 150 µg Fe/mL. The in vivo ORI sensitivity was sufficient to detect the accumulation of MION in macrophages infiltrating healing myocardial infarcts, but the specificity was limited by non‐specific areas of positive contrast at the air/tissue interfaces of the thoracic wall and the descending aorta. Improved specificity and linearity can, however, be expected at lower fields where decreased on‐resonance water linewidths, reduced air‐induced resonance shifts, and longer T2 relaxation times are observed. The optimal performance of ORI will thus likely be seen at low fields, with moderate MION concentrations and with sequences containing very short TEs. Copyright © 2007 John Wiley & Sons, Ltd.
Strongly coupled versus uncoupled spin response to radio frequency interference effects: application to glutamate and glutamine in spectroscopic imaging
Authors: Snyder Jeff , Thompson Richard B. , Wild Jim M. , Wilman Alan H.
Published: October 2007

It is well known that comparable radio frequency (RF) wavelengths and human head dimensions at high fields can lead to an inhomogeneous RF field when using standard RF transmission. However, the impact of RF inhomogeneity on potential differences in quantification between coupled and uncoupled spins at longer echo times has not been investigated thoroughly. The consequence of this RF interference on metabolite quantification in spectroscopic imaging at 4.7 T was investigated for the strongly coupled spin systems of glutamate and glutamine at an echo time of 120 ms, and compared with the singlet response of choline. These effects were studied using a single‐voxel PRESS sequence (α–2α–2α) with varying flip angle (α) from 90° to 65° in simulation, phantom, and in vivo experiments. Phantom metabolite yield decreased to 57% for choline and 27% for glutamate/glutamine in agreement with the simulations. Even a minor reduction from α = 85° to 80° produced a large difference between coupled and uncoupled yields, with a reduction of 7% for choline and 17% for glutamate/glutamine. Anecdotal in vivo spectroscopic imaging studies show similar trends, with large differences between choline and glutamate/glutamine yield over a small, 2.2 cm, region. These results demonstrate severe effects on metabolite yield due to RF variation between strongly coupled and uncoupled spin systems at long echo time, which complicates metabolite quantification. Copyright © 2007 John Wiley & Sons, Ltd.
Inverse formulation for geometrically exact stress resultant shells
Authors: Zhou Xianlian , Lu Jia
Published: October 2007

The inverse elastostatic method deals with a class of problems in which a deformed configuration of an elastic body is known while the initial stress‐free configuration or the stress in the deformed state is to be determined. The method is imperative for certain problems in engineering applications. Computational methods of inverse elastostatics have been established for elastic continua. In this paper, we present an inverse method for thin‐wall structures modeled as geometrically exact stress resultant shells. The theoretical basis and the details of implementation are discussed. Numerical examples involving both isotopic and anisotropic materials are presented. The practical utility of the method is demonstrated using an example of human aneurysm stress analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Delay‐dependent guaranteed cost gain‐scheduling control of LPV state‐delayed systems
Authors: Kucukdemiral I. B.
Published: October 2007

Delay‐dependent gain‐scheduling controller design problem is addressed for the linear parameter‐varying state‐delayed systems with time‐varying delays. By choosing a Lyapunov–Krakovskii functional, delay‐dependent conditions for the existence of guaranteed cost gain‐scheduling controller are obtained. Besides, an algorithm is also presented to solve resultant nonconvex matrix inequalities in terms of linear matrix inequalities. Finally, three numerical examples with simulations are illustrated in order to demonstrate the validity of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.