bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of TiNxO2–x Photoelectrodes with NH3 Under Controllable Middle Pressures for Dye‐Sensitized Solar Cells
Authors: Wang Xin , Yang Yulin , Jiang Zhaohua , Fan Ruiqing 
Published: June 2009

AbstractAs part of our efforts to find a way to control the concentration of N‐doped TiO2, TiNxO2–x powders were prepared by a device of our own design. In this research, photoelectrodes are generated using N‐doped TiO2 materials where the concentrations are adjusted by the amount of NH3 under middle pressure, which is seldom reported. Considerable efforts have been directed to the study of the optical absorption edge that is redshifted towards the visible‐light region. Therefore, N‐doped TiO2 electrodes are characterized by SPS and TPV analyses as experimental and theoretical studies. Experimental results indicate that the band gap of the semiconductor has been narrowed by increasing the concentration of the N‐doped TiO2. The overall conversion efficiency of the solar cell has shown that the photoelectrical properties of the N‐doped TiO2 have greatly improved with different concentrations. It can therefore be concluded that the synthesis route we found through this study is an effective way to adjust the relationship between the concentration and the band gap of the N‐doped TiO2 photoelectrodes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Coupling Radical and Ionic Processes: An Unusual Rearrangement Affords Sugar and C‐Glycoside Derivatives
Authors: Boto Alicia , Hernández Dácil , Hernández Rosendo , Álvarez Eleuterio 
Published: June 2009

AbstractAn unusual scission–rearrangement process, which couples radical and ionic reactions, was observed with galactofuranose derivatives. This one‐pot procedure afforded, in good yields, highly functionalized 1,4‐dioxanes, which could be considered as six‐membered‐ring sugar analogues. The synthesis of C‐glycoside analogues is also possible with this methodology.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Direct Electrochemistry and Electrocatalysis of the Hemoglobin Immobilized on Diazonium‐Functionalized Aligned Carbon Nanotubes Electrode
Authors: Yang Jing , Xu Ying , Zhang Renyi , Wang Yanzhi , He Pingang , Fang Yuzhi 
Published: June 2009

AbstractA simple and efficient electrochemical method is utilized to functionalize aligned carbon nanotubes (ACNTs) by the electrochemical reduction of 4‐carboxyphenyl diazonium salt. Thus hemoglobin (Hb) molecules were covalently immobilized on the diazonium‐ACNTs surface via carbodiimide chemistry. Direct electrochemistry and bioelectrocatalytic activity of the immobilized Hb were then investigated by cyclic voltammetry (CV) and amperometry techniques. It is showed that the Hb film on the diazonium‐ACNTs electrode had well‐defined redox peaks with a formal potential (E°) at −312 mV (vs. Ag/AgCl), and the Hb‐ACNTs electrode displayed good electrocatalytic activity to H2O2 reduction. Owing to the high Hb covering on the ACNTs surface (Γ*=2.7×10−9 mol cm−2), the catalytic current were significantly improved when compared to the current measured at an Hb‐tangled carbon nanotubes electrode. The Hb‐ACNTs electrode exhibited high sensitivity, long‐term stability and wide concentration range from 40 μM to 3 mM for the amperometric detection of H2O2. The heterogeneous reaction rate constant (ks) was 0.95±0.05 s−1 and the apparent Michaelis–Menten constant (K$\rm{ {_{m}^{app}})}$ was 0.15 mM.
Fabrication of Fe(CN)63− Functionalized PDDA/CdTe Layer‐by‐layer Film with Good Electron Transfer Ability
Authors: Luan Qingfen , Li Jun , Yao Xin 
Published: June 2009

Abstract(PDDA/CdTe)n layer‐by‐layer (LBL) film immobilized with Fe(CN)63− was fabricated on the gold electrode. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to investigate the electrochemical properties of this film. The peak current of the immobilized Fe(CN)63− increased as the number of the bilayers increased and was proportional to the scan rate. Compared with pure (PDDA/CdTe)n and (PDDA/PSS)n LBL film, Fe(CN)63− immobilized (PDDA/CdTe)n LBL film had good electron transfer ability. The immobility of Fe(CN)63− into the film was attributed to its interaction with Cd2+ on the surface of CdTe QDs. Fe(CN)63− also can interact with other metal ions, which would make Fe(CN)63− release from the film. The concentrations of metal ions will affect the CV response of Fe(CN)63− immobilized LBL film. It has provided a novel prototype of device or sensor for quantitative detection of metal ions.
Potentiometry of Anionic Polyelectrolytes by Quaternary Ammonium Ion‐Selective Electrode with Quaternary Ammonium Ion Added as Probe
Authors: Zheng Xiang‐Yang , Yano Daisaku , Yasui Takashi , Takada Kazutake , Yuchi Akio 
Published: June 2009

AbstractFor potentiometric determination of anionic polyelectrolytes (APEs), the free concentration of water‐soluble quaternary ammonium cation (QA+) added as a probe was measured with a quaternary ammonium ion‐selective electrode. The optimized detection of polyacrylate as one example of APEs demonstrated that the quaternary ammonium ions with a single alkyl group >C15 had large potential changes (−80 mV for C16 and −130 mV for C18) within a concentration range of 10−6–10−4 mol dm−3. The response was rapid (several minutes) and independent of pH>8 and showed no hysteresis. APEs with other anionic functional groups, for example, heparin and poly(4‐styrenesulfonate), were also detected.
Solid‐Contact Reference Electrodes Based on Lipophilic Salts
Authors: Mattinen Ulriika , Bobacka Johan , Lewenstam Andrzej 
Published: June 2009

AbstractA novel solid‐contact reference electrode (SCRE) for potentiometric measurements is studied. A lipophilic salt was introduced into a PVC membrane by two different approaches, i) using tetra(alkyl)ammonium‐tetra(butyl or phenyl)borate, i.e. a single salt (Φ+Ψ−), and ii) tetra(alkyl)ammonium chloride+potassium tetra(phenyl)borate i.e. two salts (Φ+Cl−) and (K+Ψ−) that presumably form (T(alkyl)A+T(phenyl)B−) and potassium chloride (KCl) in the membrane. The effect of the salt size on the performance of the SCRE was studied by preparing membranes using compounds with varying alkyl chain lengths. To get reference electrodes, these membranes were drop cast on two different substrates: glassy carbon (GC) disks covered with the conductive polymer (poly(3,4‐ethylenedioxythiophene) doped with chloride (PEDOT‐Cl), or silver disks coated with silver chloride (Ag/AgCl). The potential response of these electrodes was investigated in several potentiometric experiments using a conventional double junction silver chloride electrode as a reference. It was found that electrodes with the tetrabutylammonium tetrabutylborate (TBA‐TBB, single salt) in the membrane were insensitive to changes in electrolyte concentrations but reached stable potentials slowly after changes in the sample electrolyte. The double salt approach, where KCl was also present in the membrane, improved the response time, but these electrodes were more sensitive to concentration changes.
Hypothesis: Bifunctional mitochondrial proteins have centrosomal functions
Authors: Moore Akilah , Golden Andy 
Published: June 2009

AbstractMitochondria are dynamic organelles that are involved in a number of diverse processes. Most often the mitochondrion is associated with energy generation, but other important processes occur in this organelle such as fatty acid synthesis and amino acid metabolism. Although mitochondria encode less than 40 genes, all of the other ∼1,000 genes required for their function are nuclear encoded. The protein products from these nuclear encoded genes are subsequently translocated to the mitochondria and utilized in the variety of processes within the organelle. Is it possible then that any of these nuclear encoded proteins could be translocated to other areas of the cell to participate in functions not normally attributed to the mitochondria? There is growing evidence that mitochondrial proteins not only localize to sites outside of the organelle, but also have functionality at these other locales. We suggest that a subset of nuclear encoded mitochondrial proteins are bifunctional and are involved in processes outside of the mitochondria. In this perspective, we will discuss published data demonstrating mitochondrial proteins that influence progression of the cell cycle, alter chromosome morphology, localize to centrosomes, and affect centrosome number in the cell. Overall, the mitochondrion is an interesting organelle that participates in a variety of vital functions. We suggest that these essential functions are not solely due to the ability of the mitochondria to produce high amounts of energy. Throughout this discussion we attempt to demonstrate that a cell cannot live without mitochondria and study this issue from a nonenergetic perspective. Environ. Mol. Mutagen., 2009. Published 2009 Wiley‐Liss, Inc.
Cosmogenic 21Ne analysis of individual detrital grains: Opportunities and limitations
Authors: Codilean Alexandru T. , Bishop Paul , Hoey Trevor B. , Stuart Finlay M. , Fabel Derek 
Published: June 2009

AbstractWe use a numerical model describing cosmogenic nuclide acquisition in sediment moving through the upper Gaub River catchment to evaluate the extent to which aspects of source area geomorphology and geomorphological processes can be inferred from frequency distributions of cosmogenic 21Ne (21Nec) concentrations in individual detrital grains. The numerical model predicts the pathways of sediment grains from their source to the outlet of the catchment and calculates the total 21Nec concentration that each grain acquires along its pathway. The model fully accounts for variations in nuclide production due to changes in latitude, altitude and topographic shielding and allows for spatially variable erosion and sediment transport rates. Model results show that the form of the frequency distribution of 21Nec concentrations in exported sediment is sensitive to the range and spatial distribution of processes operating in the sediment's source areas and that this distribution can be used to infer the range and spatial distribution of erosion rates that characterise the catchment. The results also show that lithology can affect the form of the 21Nec concentration distribution indirectly by exerting control on the spatial pattern of denudation in a catchment. Model results further indicate that the form of the distribution of 21Nec concentrations in the exported sediment can also be affected by the acquisition of 21Nec after detachment from bedrock, in the diffusive (hillslope) and/or advective (fluvial) domains. However, for such post‐detachment nuclide acquisition to be important, this effect needs to at least equal the nuclide acquisition prior to detachment from bedrock. Copyright © 2009 John Wiley and Sons, Ltd.
Amount and controls of the quaternary denudation in the Ardennes massif (western Europe)
Authors: Demoulin A. , Hallot E. , Rixhon G. 
Published: June 2009

AbstractIt is still debated whether the primary control on the middle Pleistocene denudation of the uplifted Ardennes massif (western Europe) is tectonic or climatic. Here, based on geomorphological observations, we calculate the amount of river incision and interfluve denudation in the Meuse basin upstream of Maastricht since 0·7 Ma and we show that the main response to tectonic forcing was incision. This allows us to provide first‐order estimates of the tectonic and climatic contributions to the denudation of the Ardennes. From a dataset of 71 remnants of a terrace level dated ∼0·7 Ma, we first derive a basin‐scale functional relationship linking incision with distances to the regional base level (Lc) and to the source (Ls) in the Ourthe basin (pertaining to the Ardennian part of the Meuse basin). Expressed as I = I0*(1 – a*Lcb/Lsc), I0 being the incision measured at the basin outlet, this relationship calculates that river incision has removed 84 km3 of rock in the Meuse basin upstream of Maastricht since 0·7 Ma. In the same time, 292 km3 were eroded from the interfluves. A comparison of these volumes shows that the tectonically forced river incision accounts for ∼22% of the total post‐0·7 Ma denudation. Furthermore, the mean denudation rate corresponding to our geomorphological estimate of the overall denudation in the Meuse basin since 0·7 Ma amounts to 27 mm/ky, a figure significantly lower than the ∼40 mm/ky mean rate derived from 10Be studies of terrace deposits of the Meuse (Schaller et al., 2004). This suggests that, taken as a basin average, the 10Be‐derived rate is overestimated, probably due to an overrepresentation of the erosion products of the rapidly incising valleys in the alluvial deposits. Copyright © 2009 John Wiley & Sons, Ltd.
The critical role of climate and saprolite weathering in landscape evolution
Authors: Dixon Jean L. , Heimsath Arjun M. , Amundson Ronald 
Published: June 2009

AbstractLandscapes evolve in response to external forces, such as tectonics and climate, that influence surface processes of erosion and weathering. Internal feedbacks between erosion and weathering also play an integral role in regulating the landscapes response. Our understanding of these internal and external feedbacks is limited to a handful of field‐based studies, only a few of which have explicitly examined saprolite weathering. Here, we report rates of erosion and weathering in saprolite and soil to quantify how climate influences denudation, by focusing on an elevation transect in the western Sierra Nevada Mountains, California. We use an adapted mass balance approach and couple soil‐production rates from the cosmogenic radionuclide (CRN) 10Be with zirconium concentrations in rock, saprolite and soil. Our approach includes deep saprolite weathering and suggests that previous studies may have underestimated denudation rates across similar landscapes. Along the studied climate gradient, chemical weathering rates peak at middle elevations (1200–2000 m), averaging 112·3 ± 9·7 t km–2 y–1 compared to high and low elevation sites (46·8 ± 5·2 t km−2 y−1). Measured weathering rates follow similar patterns with climate as those of predicted silica fluxes, modeled using an Arrhenius temperature relationship and a linear relationship between flux and precipitation. Furthermore, chemical weathering and erosion are tightly correlated across our sites, and physical erosion rates increase with both saprolite weathering rates and intensity. Unexpectedly, saprolite and soil weathering intensities are inversely related, such that more weathered saprolites are overlain by weakly weathered soils. These data quantify exciting links between climate, weathering and erosion, and together suggest that climate controls chemical weathering via temperature and moisture control on chemical reaction rates. Our results also suggest that saprolite weathering reduces bedrock coherence, leading to faster rates of soil transport that, in turn, decrease material residence times in the soil column and limit soil weathering. Copyright © 2009 John Wiley & Sons, Ltd.
Intact ash and charred litter reduces susceptibility to rain splash erosion post‐wildfire
Authors: Zavala Lorena M. , Jordán Antonio , Gil Juan , Bellinfante Nicolás , Pain Colin 
Published: June 2009

AbstractThis paper describes the changes in soil water repellency and soil hydrological and erosional responses to rainfall at small‐plot scale, arising from a prescribed fire immediately following burning and one year later in a Mediterranean heathland in the area of the Strait of Gibraltar (southern Spain). Very little research has been carried out about the modifications on the ground surface after fire immediately after burning. A prescribed fire was conducted to study short‐term changes of the ground surface immediately and one year following burning. After a prescribed fire, a homogeneous charred litter layer and ash‐bed covered the mineral soil surface. This cover stayed stable on the soil surface during a period of seven days, until strong winds redistributed litter and ashes. The hydrophobicity of the exposed surface (litter and ashes) decreased considerably in relation with the litter layer properties before the fire. Ponding, runoff coefficients and soil loss were determined using simulated rainfall over the litter layer, the ash‐bed and the bare soil. Significant differences were not detected between pre‐ and post‐fire soil loss rates while a charred litter and thick ash layer were present on the ground surface. Runoff and erosion rates increased and time to ponding and runoff decreased when the charred litter and ash layers were artificially removed and the bare soil was exposed. Although wildfires will increase soil erodibility, the trends observed in this study suggest that this increased susceptibility to erosion from rainsplash processes may be limited to some degree while an intact ash and charred litter layer is still present. Copyright © 2009 John Wiley & Sons, Ltd.
Loss of astrocytic glutamate transporters in Wernicke encephalopathy
Authors: Hazell Alan S. , Sheedy Donna , Oanea Raluca , Aghourian Meghmik , Sun Simon , Jung Jee Yong , Wang Dongmei , Wang Chunlei 
Published: June 2009

AbstractWernicke encephalopathy (WE), a neurological disorder caused by thiamine deficiency (TD), is characterized by structural damage in brain regions that include the thalamus and cerebral cortex. The basis for these lesions is unclear, but may involve a disturbance of glutamatergic neurotransmission. We have therefore investigated levels of the astrocytic glutamate transporters EAAT1 and EAAT2 in order to evaluate their role in the pathophysiology of this disorder. Histological assessment of the frontal cortex revealed a significant loss of neurons in neuropathologically confirmed cases of WE compared with age‐matched controls, concomitant with decreases in α‐internexin and synaptophysin protein content of 67 and 52% by immunoblotting. EAAT2 levels were diminished by 71% in WE, with levels of EAAT1 also reduced by 62%. Loss of both transporter sites was confirmed by immunohistochemical methods. Development of TD in rats caused a profound loss of EAAT1 and EAAT2 in the thalamus accompanied by decreases in other astrocyte‐specific proteins. Treatment of TD rats with N‐acetylcysteine prevented the downregulation of EAAT2 in the medial thalamus, and ameliorated the loss of several other astrocyte proteins, concomitant with increased neuronal survival. Our results suggest that (1) loss of EAAT1 and EAAT2 glutamate transporters is associated with structural damage to the frontal cortex in patients with WE, (2) oxidative stress plays an important role in this process, and (3) TD has a profound effect on the functional integrity of astrocytes. Based on these findings, we recommend that early treatment using a combination of thiamine AND antioxidant approaches should be an important consideration in cases of WE. © 2009 Wiley‐Liss, Inc.
Circumferential pharyngeal reconstruction: History, critical analysis of techniques, and current therapeutic recommendations
Authors: Patel Rajan S. , Goldstein David P. , Brown Dale , Irish Jonathan , Gullane Patrick J. , Gilbert Ralph W. 
Published: June 2009

AbstractReconstruction of circumferential pharyngeal defects following total pharyngolaryngectomy presents major challenges with respect to surgical morbidity and restoration of functional deficits, which are often made more demanding by the increasing trend to utilize primary chemoradiation protocols with surgery reserved for salvage cases. The present review evaluates the reconstructive techniques described in the literature, including historical techniques as well as more recent innovative methods. Each technique is critically appraised with particular reference to postoperative morbidity and functional rehabilitation. Treatment recommendations are made based on the available evidence. © 2009 Wiley Periodicals, Inc. Head Neck, 2010
Approaches to measuring the effects of wake‐promoting drugs: a focus on cognitive function
Authors: Edgar Christopher J. , Pace‐Schott Edward F. , Wesnes Keith A. 
Published: June 2009

AbstractObjectivesIn clinical drug development, wakefulness and wake‐promotion may be assessed by a large number of scales and questionnaires. Objective assessment of wakefulness is most commonly made using sleep latency/maintenance of wakefulness tests, polysomnography and/or behavioral measures. The purpose of the present review is to highlight the degree of overlap in the assessment of wakefulness and cognition, with consideration of assessment techniques and the underlying neurobiology of both concepts.DesignReviews of four key areas were conducted: commonly used techniques in the assessment of wakefulness; neurobiology of sleep/wake and cognition; targets of wake promoting and/or cognition enhancing drugs; and ongoing clinical trials investigating wake promoting effects.ResultsThere is clear overlap between the assessment of wakefulness and cognition. There are common techniques which may be used to assess both concepts; aspects of the neurobiology of both concepts may be closely related; and wake‐promoting drugs may have nootropic properties (andvice versa). Clinical trials of wake‐promoting drugs often, though not routinely, assess aspects of cognition.ConclusionsRoutine and broad assessment of cognition in the development of wake‐promoting drugs may reveal important nootropic effects, which are not secondary to alertness/wakefulness, whilst existing cognitive enhancers may have underexplored or unknown wake promoting properties. Copyright © 2009 John Wiley & Sons, Ltd.
Modelling snow melt and snowcover depletion in a small alpine cirque, Canadian Rocky Mountains
Authors: DeBeer Christopher M. , Pomeroy John W. 
Published: June 2009

AbstractSpatial and temporal patterns of areal snowcover depletion (SCD) were studied over a small (<0·6 km2) alpine cirque within the Canadian Rocky Mountains using a combined approach of daily acquisition of remotely sensed imagery, together with meteorological observations and snowmelt modelling. Digital terrestrial photographs were georeferenced using a novel software tool together with a high‐resolution digital elevation model and used to derive measurements of fractional snowcovered area (SCA) over the cirque. Manual snow surveys carried out in the pre‐melt period were used to describe the initial frequency distribution of snow water equivalent (SWE) values over the cirque, and indicated a lognormal distribution of SWE when surveys were stratified by terrain features. Rates of snowmelt were simulated using a physically based snowmelt energy balance model, Snobal, driven by observed meteorological conditions at a nearby station, which were adjusted for slope orientation and exposure by making corrections to observed incoming shortwave and longwave radiation components in the cold regions hydrological model platform. Simulated melt rates were then applied to the approximated SWE distributions to model the decline in SCA over the spring. The model was found to perform well for the simulation of snowmelt based on point observations of SWE at the meteorological station, and produced a close correspondence between simulated and observed SCD curves representing two opposing slopes within the cirque. The results show that both the pre‐melt distributions of SWE and the spring melt rates exhibit considerable spatial variability between distinct slope units within the cirque, and that this variability has a significant impact on simulated SCD. Assuming a unimodal pre‐melt frequency distribution and conditions of spatially uniform snowmelt over complex terrain such as this can lead to large errors in the simulation results. It is suggested that modelling applications intended to represent snowmelt dynamics and areal SCD in similar alpine environments consider the effects of spatial variation in SWE distribution and melt energetics between slopes. Copyright © 2009 John Wiley & Sons, Ltd.