bluuebunny/crossref_metadata_2025_split huggingface dataset:
Denitrification in a hyporheic riparian zone controlled by river regulation in the Seine river basin (France)
Authors: Curie F. , Ducharne A. , Sebilo M. , Bendjoudi H. 
Published: November 2008

AbstractThe purpose of this paper is to study denitrification and the conditions for its development in a hyporheic zone. The study site is the riparian zone of a former branch of the Seine River, where the river stage is kept almost constant during the year by hydraulic regulation. Hydrological and geochemical surveys were performed by monitoring four wells, ten shorter piezometers and the river over a 15‐month period. The water fluxes originating from the chalky hillsides and the river converge in a zone parallel to the river that acts as a drainage flow path through the floodplain. The riparian zone between this flow path and the river shows an important depletion of nitrate during the summer and autumn period, which cannot be explained by a simple mixing of waters coming from the river and the chalky hillsides. It can be attributed to denitrification as it occurs when oxygen concentration is below 2 mg l−1, and goes along with a consumption of dissolved organic carbon and a decrease of redox potential. The river completely controls these hydro‐geochemical conditions. It also keeps the wetness of the riparian zone almost constant, which allowed us to isolate the high temperatures in summer and autumn as an important triggering factor for denitrification through its influence on the reaction rate and oxygen deficits. We also found a small isotopic enrichment of nitrate, suggesting that denitrification occurs after diffusion of nitrate through the sediment and riparian zone matrix, which is consistent with the hyporheic functioning of the study site. Copyright © 2008 John Wiley & Sons, Ltd.
The effects of climate change and urbanization on the runoff of the Rock Creek basin in the Portland metropolitan area, Oregon, USA
Authors: Franczyk Jon , Chang Heejun 
Published: November 2008

AbstractClimate changes brought on by increasing greenhouse gases in the atmosphere are expected to have a significant effect on the Pacific Northwest hydrology during the 21st century. Many climate model simulations project higher mean annual temperatures and temporal redistribution of precipitation. This is of particular concern for highly urbanized basins where runoff changes are more vulnerable to changes in climate. The Rock Creek basin, located in the Portland metropolitan area, has been experiencing rapid urban growth throughout the last 30 years, making it an ideal study area for assessing the effect of climate and land cover changes on runoff. A combination of climate change and land cover change scenarios for 2040 with the semi‐distributed AVSWAT (ArcView Soil and Water Assessment Tool) hydrological model was used to determine changes in mean runoff depths in the 2040s (2030–2059) from the baseline period (1973–2002) at the monthly, seasonal, and annual scales. Statistically downscaled climate change simulation results from the ECHAM5 general circulation model (GCM) found that the region would experience an increase of 1·2 °C in the average annual temperature and a 2% increase in average annual precipitation from the baseline period. AVSWAT simulation shows a 2·7% increase in mean annual runoff but a 1·6% decrease in summer runoff. Projected climate change plus low‐density, sprawled urban development for 2040 produced the greatest change to mean annual runoff depth (+5·5%), while climate change plus higher‐density urban development for 2040 resulted in the smallest change (+5·2%), when compared with the climate and land cover of the baseline period. This has significant implications for water resource managers attempting to implement adaptive water resource policies to future changes resulting from climate and urbanization. Copyright © 2008 John Wiley & Sons, Ltd.
Local matrix metalloproteinase 2 gene knockdown in balloon‐injured rabbit carotid arteries using nonviral‐small interfering RNA transfection
Authors: Hlawaty Hanna , San Juan Aurélie , Jacob Marie‐Paule , Vranckx Roger , Letourneur Didier , Feldman Laurent J. 
Published: November 2008

AbstractBackgroundSmall interfering RNA (siRNA) delivery is a promising approach for the treatment of cardiovascular diseases. Matrix metalloproteinase (MMP) 2 over‐expression in the arterial wall has been implicated in restenosis after percutaneous coronary intervention, as well as in spontaneous atherosclerotic plaque rupture. We hypothesized that in vivo local delivery of siRNA targeted at MMP2 (MMP2‐siRNA) in the balloon‐injured carotid artery of hypercholesterolemic rabbits may lead to inhibition of MMP2 expression.MethodsTwo weeks after balloon injury, 5 µmol/l of Tamra‐tagged MMP2‐siRNA, scramble siRNA or saline was locally injected in the carotid artery and incubated for 1 h.ResultsFluorescent microscopy studies showed the circumferential uptake of siRNA in the superficial layers of neointimal cells. MMP2 mRNA levels, measured by the real‐time reverse transcriptase‐polymerase chain reaction, was decreased by 79 ± 25% in MMP2‐siRNA‐ versus scramble siRNA‐transfected arteries (p < 0.05). MMP2 activity, measured by gelatin zymography performed on the conditioned media of MMP2‐siRNA versus scramble siRNA transfected arteries, decreased by 53 ± 29%, 50 ± 24% and 46 ± 14% at 24, 48 and 72 h, respectively (p < 0.005 for all). No effect was observed on MMP9, pro‐MMP9 and TIMP‐2 levels.ConclusionsThe results obtained in the present study suggest that significant inhibition of gene expression can be achieved with local delivery of siRNA in the arterial wall in vivo. Copyright © 2008 John Wiley & Sons, Ltd.
Raman to the limit: tip‐enhanced Raman spectroscopic investigations of a single tobacco mosaic virus
Authors: Cialla Dana , Deckert‐Gaudig Tanja , Budich Christian , Laue Michael , Möller Robert , Naumann Dieter , Deckert Volker , Popp Jürgen 
Published: November 2008

AbstractThe development of fast identification techniques of viruses is an ongoing important research topic. Conventional virus detection and identification is generally based on various different microbiological methods. However, these techniques are not suitable for the analysis of single virus particles. Therefore, our goal is to establish tip‐enhanced Raman scattering (TERS), providing vibrational spectroscopic information with a spatial resolution less than 50 nm, to characterize single viruses at a molecular level. Here we report, to the best of our knowledge for the first time, about TERS spectra of a tobacco mosaic virus, showing the great capability of this technique. However, the application of the TERS technique for a rapid and direct detection of different species of single viruses is under development, which is useful for a wide range of analytical fields. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of cathodic protection on macrocell currents: A viable method to monitor and control the efficiency of CP?
Authors: Schwarz W. , Tritthart J. 
Published: November 2008

AbstractCorrosion protection of steel reinforcement in concrete structures by cathodic protection (CP) is a cost effective, reliable, and widely accepted method to stop and prevent the corrosion of the steel reinforcement. The efficiency of CP is usually monitored by the “24 h, 100 mV depolarization criterion,” a purely empirical criterion whose implementation is cost and labor intensive and that does not allow online control of CP. Within an extended research project on CP applied to concrete members of a highway bridge exposed to penetrating moisture, three sets of macrocells (MC), each composed of five MC sensors, were installed in conjunction with concrete resistance sensors and silver/silver chloride reference cells. Chloride profiles were determined from the cored or drilled powder originating from the installation of sensors and from drilling cores. Corrosion currents, steel potentials, and concrete resistance were monitored over a period of 1 year before, after installing the CP systems (which remained switched off for half a year for evaluating the effect of the conductive coating), and after start‐up of the CP systems. The CP systems applied consist of a moisture resistant conductive coating. As expected CP has a pronounced effect on local MC currents: Anodic MC currents were reduced or changed into cathodic currents, whereas cathodic currents were only weakly influenced. By adjusting the applied protection current all anodic MC currents may be changed into cathodic MC currents. Results indicate that the 100 mV depolarization criterion is a conservative criterion in atmospherically exposed concrete; it is not reliable in strongly wetted concrete. There was no consistent correlation between the CP induced changes in the local MC currents and 24 h depolarization values indicating that large potential shifts induced by CP do not necessarily imply overprotection. Results show that monitoring MC currents before, during, and after CP operation allows to demonstrate in a transparent way the effect of CP on the corrosion of the steel reinforcement. Online monitoring of MC currents is proposed as a viable and comprehensible method to monitor and control the efficiency of CP.
Influence of temperature and humidity on Portland cement mortar resistivity monitored with inner sensors
Authors: Villagrán Zaccardi Y. A. , Fullea García J. , Huélamo P. , Di Maio Á. A. 
Published: November 2008

AbstractConcrete resistivity is directly related to relative humidity (RH) and is also affected by temperature. In this paper, a theoretical discussion about how these two factors affect resistivities of concrete and mortar is provided. Moreover, experimental results on sensorized mortar probes are presented and correlated to analytical models of temperature and humidity influences. All measurements were performed under controlled conditions. Temperature, RH, and resistivity were measured simultaneously in a particular zone of the probes. Temperature scanning was performed over short periods of time (approximately 1 h) and the probes were covered with waterproof paraffin each time for constant humidity content. This was feasible as all sensors were embedded. Water contents were ensured during the experiment by weighting the probes. Conclusions on the applicability of these techniques, their advantages, and limitations, and correlation to Archie and Arrhenius laws of the results are made.
Stress corrosion cracking and selective corrosion of copper‐zinc alloys for the drinking water installation
Authors: Brandl E. , Malke R. , Beck T. , Wanner A. , Hack T. 
Published: November 2008

AbstractDespite a generally good corrosion resistance to tap and industrial water, many brass taps and fittings have failed in the past by stress corrosion cracking (SCC) and selective corrosion (dezincification or preferred removal of a phase). The experimental investigations of the present study clarify the influence of the ammonia concentration on the two types of corrosion. Notched specimens made of the alloys CuZn39Pb3, CuZn40Pb2, CuZn37, CuZn36Pb2As and CuZn21Si3P are polarized anodically in pure tap water and tap water with realistic ammonia concentrations (15 and 30 ppm) under a simultaneous mechanical loading condition. The influence of stress and of the third alloying elements lead and arsenic are investigated and evaluated. The experiments show that the ammonia additions significantly increase the risk of dezincification of the α‐β‐brasses. The arsenic in the CuZn36Pb2As alloy avoids dezincification, but enhances the risk of SCC. The rate of selective corrosion and SCC consistently increases with increase in tensile stress.
Study of a purple gold‐based alloy resistance to tarnishing in a sulphuric solution
Authors: Carvalho O. , Soares D. , Fonseca A. , Silva F. S. 
Published: November 2008

AbstractThe stability of some coloured gold alloys is dependent on the environment. In this work, the effect of a sulphuric solution on the physical properties of a purple gold‐based alloy is studied. Changes in the physical properties of the samples namely colour, brightness and reflectance were measured with time in the referred environment. It was observed that significant changes occurred even for a small exposure time. A selective dissolution of aluminium was found to be the main alloy corrosion mechanism, which is responsible for the changes in superficial physical characteristics. At the end of the experiments, the sample surface modification was analyzed by optical and SEM/EDS microscopy. The surface corrosion process resulted in the formation of a large number of superficial fissures with a significant thickness and length, essentially in the Al2Au phase. XPS spectroscopy was used in order to identify the compounds formed in the corrosion process.
Investigations on the re‐passivation of carbon steel in chloride containing concrete in consequence of cathodic polarisation
Authors: Eichler T. , Isecke B. , Bäßler R. 
Published: November 2008

AbstractAlthough the complex changes at the steel–concrete interface due to cathodic polarisation are widely acknowledged to have a beneficial influence concerning the cathodic protection (CP) of steel in concrete, some questions concerning the repassivation of carbon steel in consequence of cathodic polarisation are still not satisfactorily clarified. In the recent literature, some indications are presented that repassivation occurs after a certain time of polarisation. Therefore, the investigations discussed in this paper aim to clarify, to what extent the re‐passivation of carbon steel due to cathodic polarisation occurs, and if the ennoblement of OCP is a sufficient indication for repassivation. In a first step, the corrosion state of five nominal equal test specimens was determined by electrochemical impedance spectroscopy (EIS). After determining the initial corrosion state by evaluating the charge transfer resistance and the polarisation resistance, respectively, the specimens were polarised cathodically. Impedance data were recorded before, during and after polarisation. The impedance data were evaluated by equivalent circuit fitting with special attention to charge transfer resistances and the impact of diffusion on the corrosion and polarisation behaviour. The results indicate that the reduction of oxides and oxygen diffusion during cathodic polarisation has strong impact on the systems behaviour and that repassivation effects occur after switching off the polarisation current and during depolarisation, respectively.
Conventional and pulse cathodic protection of reinforced concrete: Electrochemical behavior of the steel reinforcement after corrosion and protection
Authors: Koleva D. A. , Guo Z. , van Breugel K. , de Wit J. H. W. 
Published: November 2008

AbstractThe applicability and efficiency of an alternative for impressed current cathodic protection (CP) for reinforced concrete, based on pulse technology, was investigated. The technique, denoted as pulse CP (pCP), was evaluated on the basis of a comparative analysis to reference (non‐corroding), corroding, and conventional CP conditions, in terms of long‐term monitoring of electrochemical parameters for the embedded steel with time of corrosion and protection. The hereby reported results are for the total duration of the experiment, i.e., 460 days of conditioning, also presented in comparison with earlier stages. Protection was applied after corrosion was initiated (using corrosion medium of 5% NaCl), at different time intervals (here reported are starting points 60 and 150 days of age). Both CP regimes used current density of 5 or 20 mA/m2 steel surface. The pulse CP was applied as a pulse‐shaped block current (square wave) with the current itself being the feedback control signal, using 12.5–50% duty cycle at 500 Hz to 1 kHz frequency. Under equal environmental conditions and for a comparatively long period of application, the pulse CP was found to perform as effectively as the conventional CP with regard to electrochemical behavior of the steel reinforcement. Furthermore, the pulse CP technique was found to achieve more rapidly the so called “open circuit potential (OCP) passivity” as a result of an enhanced ion transport (chloride withdrawal) and more favorable cement chemistry (increased alkalinity around the steel reinforcement).
Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic 1H NMR spectroscopy
Authors: Culf A. S. , Čuperlović‐Culf M. , Ouellette R. J. 
Published: November 2008

AbstractHighly coloured Janovsky complexes have been known for over 120 years, being used in many colourimetric analytical procedures. In this present study, two novel and stable nitrocyclohexadienyl spirobicyclic, zwitterionic Janovsky anionic hydantoin σ‐complexes, rac‐1,3‐diisopropyl‐6‐nitro‐2,4‐dioxo‐1,3‐diazaspiro[4.5]deca‐6,9‐dien‐8‐ylideneazinate, ammonium internal salt (1) and 1,3‐diisopropyl‐2,4‐dioxo‐1,3‐diazaspiro[4.5]deca‐6,9‐dien‐8‐ylideneazinate, ammonium internal salt (2) have been prepared and characterised by NMR, electrospray ionization mass spectrometry (ESI‐MS) and UV/visible methods. For the p‐mononitro‐substituted complex (2), we discovered chemical exchange behaviour using 1D saturation transfer and 2D exchange spectroscopy (EXSY) 1H NMR techniques. The coalescence temperature was determined to be 62 °C in d3‐acetonitrile. Analysis of these data provided a Gibbs free energy of activation, ΔG ‡, of + 67 kJ mole−1, a rate constant, k, coalescence of 220 Hz and an equilibrium constant, Keqm, of 0.98 as estimates of the exchange process in this solvent. Of the two mechanisms proposed for this fluxional behaviour, ring opening to a substituted benzene or proton exchange, a further theoretical modelling study of 1D 1H NMR spectra was able to confirm that simple proton exchange between the two nitrogen sites of the hydantoin ring provided an accurate simulation of the observed experimental evidence. Interestingly, the o,p‐dinitro‐substituted complex (1) did not show any chemical exchange behaviour up to 150 °C in d3‐acetonitrile (to 75 °C) and d6‐dimethyl sulfoxide (DMSO). Molecular modelling at the MM2 level suggests that steric collisions of an N‐acyl isopropyl substituent of the hydantoin ring with the ortho‐nitro group of the spirofused cyclohexadienyl ring prevents the proposed proton exchange mechanism occurring in this case. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd
Complete assignments of NMR data of salens and their cobalt (III) complexes
Authors: Woo Yoonkyung , Koh Dongsoo , Lim Yoongho 
Published: November 2008

AbstractSalens, derived from 1,2‐ethylenediamine and salicylaldehydes, have been widely used as ligands for metal complexes which have been showing enormous potential in chemical properties of asymmetric catalysts as well as biological properties such as anticancer agents. Almost all of the salen–metal complexes with their corresponding metal (II)‐complexes show the evidences of chelation of two oxygens in salens. However, several metal (II) complexes, especially cobalt (II) complexes, could not show NMR spectra due to their paramagnetism. Recently, it has been reported that one of the cobalt (III) complexes was used for NMR spectroscopy to evaluate its stereoselectivity as a catalyst. Even though many salen ligands are known, their NMR data are not assigned completely. It was possible that modification in northern part of salen with 2‐hydroxyphenyl group afforded another oxygen chelation site in salen ligand. Here we report that synthesis and full NMR assignment of new salen ligands, which form meso 1,2‐bis(2‐hydroxyphenyl)ethylenediamine) and their cobalt (III) complexes. The assignments of 1H and 13C NMR data obtained in this experiment can help us to predict the NMR data of other salen ligands. Copyright © 2008 John Wiley & Sons, Ltd.
Increased risk of digoxin toxicity following hospitalization
Authors: Haynes Kevin , Hennessy Sean , Localio A. Russell , Cohen Abigail , Leonard Charles E. , Kimmel Stephen E. , Feldman Harold I. , Strom Brian L. , Metlay Joshua P. 
Published: November 2008

AbstractPurposeAdverse drug events (ADEs) are an important cause of preventable hospitalizations among elderly individuals taking high‐risk medications. The objective of the study was to identify health care system factors that affect the risk of digoxin toxicity for older adults on digoxin.MethodsWe conducted a prospective cohort study of older adults within the Pennsylvania Pharmaceutical Assistance Contract for the Elderly (PACE) program, which provides comprehensive drug benefits for older adults with low income. Subjects were interviewed at the time of enrollment regarding the management and coordination of their health care as well as medication comprehension. Hospitalizations were identified by linking patient identifiers to a state‐wide registry. Trained abstractors reviewed discharge summaries of possible digoxin related ADEs. Unadjusted and adjusted incidence rate ratios (IRR) were calculated based on person–months of exposure using Poisson regression models, with variances adjusted for within subject repeated measures.ResultsWe enrolled a total of 2030 adults on digoxin from May 2002 to June 2003. A total of 34 hospitalizations due to digoxin toxicity occurred, equivalent to 1.12 hospitalizations per 1000 person–months of exposure. Adjusting for hospitalization in the past 2 months, age, total number physicians prescribing any medications in past 3 months, total number of pharmacies filling medications in past 3 months, and number of unique prescriptions filled in the past month had a 4.25‐fold increased risk of subsequently experiencing digoxin toxicity (IRR 95%CI 1.95, 9.27).ConclusionsThe risk of digoxin toxicity‐related hospitalization, while low, is higher in the post‐hospital period. Copyright © 2008 John Wiley & Sons, Ltd.
Phonon‐assisted excitation transfer in quantum dot molecules: from quantum kinetics to transfer rates
Authors: Machnikowski Paweł , Rozbicki Emil 
Published: November 2008

AbstractWe study the process of excitation transfer between vertically stacked dots due to the combined effect of the Förster coupling and carrier–phonon interaction. A consistent Markovian approximation is derived which reasonably reproduces the quantum‐kinetic results. The impact of the exciton transfer process on the temperature‐dependent intensity of spectral lines is discussed in terms of rate equations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of momentum dependent matrix elements on scattering effects in quantum cascade lasers
Authors: Schmielau Tim , Pereira Mauro F. 
Published: November 2008

AbstractResults for our fully frequency‐ and wavevector‐dependend self‐consistent nonequilibrium Green's function simulations of electron transport through quantum cascade lasers are compared to those from a simplified approach where scattering rates are only evaluated at representative ‘typical values’ of the in‐plane momentum due to the complexity of the underlying many‐body problem and the limited computational resources available. We find a noticeable impact on electronic lineshapes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)