bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Chromium Hexacyanoferrate/Multiwalled Carbon Nanotube Composite and Its Biosensing for L‐Cysteine
Authors: Shen Rongxing , Li Xiangzi , Lium Guilin , Ji Yulan , Wang Guangfeng , Fang Bin 
Published: September 2010

AbstractThis work describes the electrochemical properties of glassy carbon electrodes (GCE) modified with chromium(III) hexacyanoferrate(II) (Crhf) nanoparticles attached multiwalled carbon nanotube (MWNTs). The morphological characterization of Crhf/MWNTs nanocomposites was examined by scanning electron microscopy (SEM), UV‐vis spectroscopy, and Fourier transform infrared spectrometry (FT‐IR). The electrocatalytic activity of these nanocomposites was investigated and showed a good electrocatalytic effect for oxidation of L‐cysteine (L‐Cys) in 0.1 M phosphate buffer solution (pH 3.0). Under optimum conditions linear calibration graphs were obtained over the L‐Cys concentration range 5.0×10−7 to 6.0×10−5 M with a correlation coefficient of 0.9998 and a detection limit (signal‐to‐noise ratio was 3) of 1.0×10−8 M. The proposed method is simple and it also showed excellent sensitivity and stability. The excellent electrocatalytic ability of the modified electrode towards L‐Cys manifests that the Crhf/MWNTs can provide a new platform for biosensors and other biology.
Electrochemical Studies of the Neuraminidase Inhibitor Zanamivir and its Voltammetric Determination in Spiked Urine
Authors: Skrzypek S. 
Published: September 2010

AbstractZanamivir is a member of a new class of antiviral agents that selectively inhibit the enzyme neuraminidase of influenza A H5N1 and H1N1 viruses. Although zanamivir is the compound of biological interest, so far it has not been a subject of any electrochemical studies. It was stated, that zanamivir can act as an electrocatalyst at HMDE. The electrode mechanism is connected with the hydrogen evolution reaction catalyzed by zanamivir as the guanidine compound. A new adsorptive catalytic method for its voltammetric (SW AdSV) determination was developed. The dependence of the peak current on pH, buffer concentration, nature of the buffer and instrumental parameters were studied. The best results were received in citrate‐phosphate buffer at pH 2.2. This electroanalytical procedure enabled to determine zanamivir in the concentration range 4.8×10−7–1.2×10−5 mol L−1 in supporting electrolyte and diluted urine. Precision, repeatability and accuracy of the method were checked in both media. The detection and quantification limits were found to be 1.5×10−7 and 4.8×10−7 mol L−1 respectively. A standard addition method was used to determine zanamivir in spiked urine.
Gold Nanoparticle Modified Screen Printed Electrodes for the Trace Sensing of Arsenic(III) in the Presence of Copper(II)
Authors: Khairy Mohamed , Kampouris Dimitrios K. , Kadara Rashid O. , Banks Craig E. 
Published: September 2010

AbstractGold ensembles for the trace level sensing of arsenic(III) in the presence of copper(II) are reported. The gold ensembles are fabricated using citrate capped gold nanoparticles which are chemically synthesised in an aqueous solution with an aliquot of this simply cast onto an economical and disposable screen printed electrode. After drying at room temperature, the gold ensembles are ready for use. The gold ensembles are explored towards the sensing of arsenic(III) in the presence of copper(II) using anodic stripping voltammetry where the corresponding stripping peaks are well resolved and using this protocol it is possible to readily detect 3 µg L−1 (3 ppb) with a detection limit of 0.4 µg L−1 (0.4 ppb). Proof‐of‐concept is also shown for the sensing of arsenic(III) in a canal water sample. Given the low cost of the sensor and ease of fabrication, the gold ensembles hold promise for the sensing of arsenic(III) in water samples where copper(II) may be present.
Electrochemical Redox Behaviour of Temozolomide Using a Glassy Carbon Electrode
Authors: Ghalkhani Masoumeh , Fernandes Isabel P. G. , Oliveira S. Carlos B. , Shahrokhian Saeed , Oliveira‐Brett Ana Maria 
Published: September 2010

AbstractThe electrochemical behaviour of temozolomide on a glassy carbon electrode has been investigated. The reduction of temozolomide is an irreversible process, pH dependent, and the mechanism involves the addition of one electron and one proton to C5 to form an anion radical, causing the irreversible breakdown of the tetrazinone ring. The oxidation mechanism of temozolomide is an irreversible, adsorption‐controlled process, pH dependent up to value close to the pKa and occurs in two consecutive charge transfer reactions, with the formation of the hydroxylated product. The electroanalytical determination of TMZ led to a detection limit of 1.1 µM.
Electrocatalytic Oxidation of Diethylaminoethanethiol and Hydrazine at Single‐walled Carbon Nanotubes Modified with Prussian Blue Nanoparticles
Authors: Adekunle Abolanle S. , Ozoemena Kenneth I. 
Published: September 2010

AbstractIn this work, edged plane pyrolytic graphite electrode EPPGE was modified with functionalised single‐walled carbon nanotubes and Prussian blue nanoparticles (PB). The modified electrode was characterised by techniques such as TEM, FTIR, XPS, EDX and cyclic voltammetry. The EPPGE‐SWCNT‐PB platform exhibited enhanced electron transport and catalytic efficiency towards the oxidation of Diethylaminoethanethiol (DEAET) and hydrazine compared with the other electrodes studied. The EPPGE‐SWCNT‐PB showed good electrochemical stability in the analytical solution, showing limit of detection in the micromolar range and catalytic rate constant of 3.71×106 and 7.56×106 cm3 mol−1 s−1 for DEAET and hydrazine respectively. The adsorption properties of these analytes that impact on their detection at the SWCNT‐PB film modified electrode were evaluated and discussed.
Electrochemical Capacitive Behaviour of Multiwalled Carbon Nanotubes Modified with Electropolymeric Films of Nickel Tetraaminophthalocyanine
Authors: Chidembo Alfred T. , Ozoemena Kenneth I. 
Published: September 2010

AbstractElectrochemical capacitive behaviour of the electropolymeric nickel tetra‐aminophthalocyanine (poly‐NiTAPc) supported on multiwalled carbon nanotube (MWCNT) platform is described. From the data in 1 M H2SO4, the MWCNT‐poly‐NiTAPc exhibited superior capacitance (112 mF cm−2 or 777 F g−1). The supercapacitance of the MWCNT‐polyNiTAPc was found to be much better in 1 M H2SO4 than in 1 M NaOH medium. Impedance data proved that most of the stored energy of the MWCNT‐poly‐NiTAPc could be accessible at high frequency (1.6 kHz). The electrode is capable of undergoing continuous charge‐discharge process for more than a 1000 cycles without any significant deterioration in the stability.
High‐Performance Amperometric Sensors Using Catalytic Platinum Nanoparticles‐Thionine‐Multiwalled Carbon Nanotubes Nanocomposite
Authors: Yu Rongmin , Wang Lihua , Xie Qingji , Yao Shouzhuo 
Published: September 2010

AbstractThionine (TH) adsorbed on multiwalled carbon nanotubes (MWCNTs) increases the load and dispersion of platinum nanoparticles (PtNPs) generated by chemical reduction of H2PtCl6 with NaBH4. Under the optimum conditions, the PtNPs‐TH‐MWCNTs/Au electrode electrocatalyzed the reduction and oxidation of H2O2 with high sensitivity, and after glucose oxidase (GOx) adsorption it responded to glucose concentration with a sensitivity of 0.14 A M−1 cm−2. The cyclic voltammetric cathodic peak current for NO2− reduction on PtNPs‐TH‐MWCNTs/Au responded linearly to NO2− concentration from 0.5 to 150 µM, with a sensitivity of 5.52 A M−1 cm−2 and a detection limit of 0.2 µM.
Comparative Studies on Electrocatalytic Activities of Chemically Reduced Graphene Oxide and Electrochemically Reduced Graphene Oxide Noncovalently Functionalized with Poly(methylene blue)
Authors: Liu Qing , Li Yang , Zhang Lanyong , Li Di , Fan Chunhai , Long Yi‐Tao 
Published: September 2010

AbstractThis study compares the electrocatalytic activities of chemically reduced graphene oxide (crGO) and electrochemically reduced graphene oxide (erGO), which are both noncovalently functionalized with a polyaromatic dye, poly(methylene blue) (polyMB), toward the oxidation of β‐nicotinamide adenine dinucleotide (NADH). PolyMB‐crGO and polyMB‐erGO composites were obtained via electropolymerization of methylene blue on crGO and GO modified glassy carbon (GC) electrodes, respectively. Cyclic voltammetry (CV) results indicate that these two types of integrated electrodes reveal different electrocatalytic activities. PolyMB‐crGO integrated electrode possesses lower catalytic oxidation potential, suggesting higher catalytic activity. The present study is helpful for the understanding and screening of graphene‐based advanced carbon nanomaterials for potential electrochemical applications.
Systems level engineering of Corynebacterium glutamicum – Reprogramming translational efficiency for superior production
Authors: Becker Judith , Buschke Nele , Bücker René , Wittmann Christoph 
Published: September 2010

AbstractIn this study, we replaced the natural start codons of different enzymes in the central carbon metabolism of Corynebacterium glutamicum to influence their activity toward improved production of the feed amino acid lysine. It was found that the translational start codon directly affects the intracellular activity of the encoded enzyme, whereby the common ATG generally led to higher values as compared with the rare variant GTG. This could be exploited to specifically amplify or attenuate enzyme activities in order to redirect carbon flux from undesired, competing pathways toward reactions supporting lysine formation. Replacement of the natural ATG codon by GTG reduced the specific enzyme activity of pyruvate dehydrogenase (PDH) and phosphoglucoisomerase by 60 and 40%, respectively. Vice versa, the activity of glucose 6‐phosphate dehydrogenase was increased by 40% by the substitution GTG‐>ATG. Implementation of the attenuated pyruvate dehydrogenase in the background of lysine producing C. glutamicum increased product yield by 17%. This was related to a redirection of the metabolic flux toward the supply of the lysine precursor oxaloacetate. The amplified expression of glucose 6‐phosphate dehydrogenase by the start codon exchange increased lysine yield by 10%, linked to an increased flux toward NADPH supply in the pentose phosphate pathway.
Enzyme‐aided wool dyeing with a neutral protease at reduced temperatures
Authors: Periolatto Monica , Ferrero Franco , Giansetti Mirco , Mossotti Raffaella , Innocenti Riccardo 
Published: September 2010

AbstractConventional wool dyeing methods are based on long times at high temperatures. These are energy intensive and can even damage the fibers, thus changing the desired fiber characteristics. In this work, enzyme pretreatment in combination with lower temperatures was used to reach exhaustion values comparable to those obtained with the standard procedure at 98°C. Kinetic runs carried out on wool yarn at different temperatures confirmed the possibility of obtaining more than 90% of bath exhaustion by dyeing at 85°C due to the pretreatment with a proteolytic enzyme. At the same temperature, without enzymatic pretreatment, just 77% of bath exhaustion can be reached. The enzyme action on the dyeing kinetics was investigated through calculation of dye absorption rate constants according to the diffusion‐limited kinetic model proposed by Chrastil. Dynamometric measurements on the yarn dyed at 98°C showed a 25% loss of tensile strength and 50% loss of elongation, while at lower temperature the values were better even after enzyme pretreatment, in agreement with the results of scanning electron microscopy analysis. A temperature of 85°C with enzyme pretreatment was found to be optimal taking into account satisfactory washing, perspiration and light fastness values.
Mitigation of Water Management in PEM Fuel Cell Cathodes by Hydrophilic Wicking Microporous Layers
Authors: Schweiss R. , Steeb M. , Wilde P. M. 
Published: September 2010

AbstractThis study introduces a novel strategy for enhancing the performance of polymer electrolyte fuel cells at high current densities by means of an advanced gas diffusion layer design. The incorporation of hydrophilic wicking agents into microporous layers of the cathode gas diffusion layer improves water management, thus increasing the maximum power density of polymer electrolyte fuel cells. Ex situ measurements with respect to water and vapour transport, and electrochemical polarisation data provide evidence suggesting that the beneficial effect has to be attributed to enhanced liquid water removal through the microporous layer.
New type of tetrazine‐substituted metallophthalocyanines by microwave irradiation: Synthesis and characterization
Authors: Saka Ece Tuǧba , Yıldırım Nuri , Kantekin Halit 
Published: September 2010

Abstract5,6‐bis(4‐methylphenyl)‐2,3‐dihydro‐1,2,3,4‐tetrazine 2 was synthesized by the dimerization of ethyl p‐methylbenzoateformylhydrazone 1 in hydrazinehydrate solution. 2,3‐bis(4‐methylphenyl)‐6,7,14,15‐tetrahydro[1,2,3,4]tetrazino [2,3d][1,8, 4,5]benzodithia‐diazecine‐10,11‐dicarbonitrile 4 was sythesized by cyclization reaction of tetrazine monomer 2 onto 1,2‐bis‐(2‐iodoethylmercapto)‐4,5‐dicyanobenzene 3. Co(II) and Cu(II) phthalocyanine complexes were prepared by reaction of the dinitrile compound (4) with the chlorides of Co(II), Cu(II), and DMAE at 175°C, 350 W in a microwave oven for 10 min. Zn(II)‐phthalocyanine complex was prepared by reaction of the dinitrile compound 4 with the acetate of Zn(II) and DMAE at 175°C, 350 W in a microwave oven for 10 min. The new compounds were characterized by a combination of IR, 1H‐NMR, 13CNMR, UV‐vis, elemental analysis, and MS spectral data. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:456–461, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20623
The male–female gap in physician earnings: evidence from a public health insurance system
Authors: Theurl Engelbert , Winner Hannes 
Published: September 2010

AbstractEmpirical evidence from US studies suggests that female physicians earn less than their male counterparts, on average. The earnings gap does not disappear when individual and market characteristics are controlled for. This paper investigates whether a gender earnings difference can also be observed in a health‐care system predominantly financed by public insurance companies. Using a unique data set of physicians' earnings recorded by a public social security agency in an Austrian province between 2000 and 2004, we find a gender gap in average earnings of about 32%. A substantial share of this gap (20–47%) cannot be explained by individual and market characteristics, leaving labor market discrimination as one possible explanation for the observed gender earnings difference of physicians. Copyright © 2010 John Wiley & Sons, Ltd.
Extinction of spatial memory alters CREB phosphorylation in hippocampal CA1
Authors: Porte Y. , Trifilieff P. , Wolff M. , Micheau J. , Buhot M.C. , Mons N. 
Published: September 2010

AbstractAlthough the importance of cAMP‐response element binding protein (CREB) phosphorylation in long‐term memory formation is well documented for hippocampus‐dependent tasks, little is known about the changes in phosphorylated CREB (pCREB) that occur during the process of extinction. The purpose of this study was to characterize the temporal patterns of pCREB in the CA1 and the amygdala after the extinction of previously acquired spatial information in the water maze. Mice were trained to find a hidden platform located at a fixed position and then were given extinction sessions in which the platform was either absent (NoPF) or relocated every day (RandomPF). We show that water maze spatial training evoked a biphasic response of pCREB in the CA1, with two different peaks occurring 15 min and 8 h postacquisition. The extinction of the original spatial preference significantly reduced the two peaks of CA1 pCREB in both RandomPF and NoPF groups whereas CA1 pCREB at 60 min post‐training remained unaffected. Moreover, the early and late phases of extinction training produced regionally dissociable effects on pCREB in the CA1 and the lateral nucleus of the amygdala. These findings provide new insights on the molecular dynamics and anatomical dissociations underlying spatial memory and extinction learning. © 2010 Wiley Periodicals, Inc.
GluK1 inhibits calcium dependent and independent transmitter release at associational/commissural synapses in area CA3 of the hippocampus
Authors: Salmen Benedikt , Beed Prateep S. , Özdogan Tugba , Maier Nikolaus , Johenning Friedrich W. , Winterer Jochen , Breustedt Jörg , Schmitz Dietmar 
Published: September 2010

AbstractCA3 pyramidal cells receive three main excitatory inputs: the first one is the mossy fiber input, synapsing mainly on the proximal apical dendrites. Second, entorhinal cortex cells form excitatory connections with CA3 pyramidal cells via the perforant path in the stratum lacunosum moleculare. The third input involves the ipsi‐and contralateral connections, termed the associational/commissural (A/C) pathway terminating in the stratum radiatum of CA3, thus forming a feedback loop within this region. Since this excitatory recurrent synapse makes the CA3 region extremely prone to seizure development, understanding the regulation of synaptic strength of this connection is of crucial interest. Several studies suggest that kainate receptors (KAR) play a role in the regulation of synaptic strength. Our aim was to characterize the influence of KAR on A/C synaptic transmission: application of ATPA, a selective agonist of the GluK1 KAR, depressed the amplitude fEPSP without affecting the size of the fiber volley. Blockade of GABA receptors had no influence on this effect, arguing against the influence of interneuronal KARs. Pharmacological and genetic deletion studies could show that this effect was selectively due to GluK1 receptor activation. Several lines of evidence, such as PPF changes, coefficient of variance–analysis and glutamate uncaging experiments strongly argue for a presynaptic locus of suppression. This is accompanied by an ATPA‐mediated reduction in Ca2+ influx at excitatory synaptic terminals, which is most likely mediated by a G‐Protein dependent mechanism, as suggested by application of pertussis toxin. Finally, analysis of miniature EPSCs in the presence and absence of extracellular Ca2+ suggest that presynaptic KAR can also reduce transmitter release downstream and therefore independent of Ca2+ influx. © 2010 Wiley Periodicals, Inc., Inc.
Layer‐specific alterations to CA1 dendritic spines in a mouse model of Alzheimer's disease
Authors: Merino‐Serrais P. , Knafo S. , Alonso‐Nanclares L. , Fernaud‐Espinosa I. , DeFelipe J. 
Published: September 2010

AbstractWhy memory is a particular target for the pathological changes in Alzheimer's Disease (AD) has long been a fundamental question when considering the mechanisms underlying this disease. It has been established from numerous biochemical and morphological studies that AD is, at least initially, a consequence of synaptic malfunction provoked by Amyloid β (Aβ) peptide. APP/PS1 transgenic mice accumulate Aβ throughout the brain, and they have therefore been employed to investigate the effects of Aβ overproduction on brain circuitry and cognition. Previous studies show that Aβ overproduction affects spine morphology in the hippocampus and amygdala, both within and outside plaques (Knafo et al., (2009) Cereb Cortex 19:586‐592; Knafo et al., (in press) J Pathol). Hence, we conducted a detailed analysis of dendritic spines located in the stratum oriens and stratum radiatum of the CA1 hippocampal subfield of APP/PS1 mice. Three‐dimensional analysis of 18,313 individual dendritic spines revealed a substantial layer‐specific decrease in spine neck length and an increase in the frequency of spines with a small head volume. Since dendritic spines bear most of the excitatory synapses in the brain, changes in spine morphology may be one of the factors contributing to the cognitive impairments observed in this AD model. © 2010 Wiley‐Liss, Inc.
Two New Sesquiterpenes from the Fungus Stereum sp.
Authors: Liu Fang‐Fang , Li Guo‐Hong , Yang Zhong‐Shan , Zheng Xi , Yang Yue , Zhang Ke‐Qin 
Published: September 2010

AbstractTwo new sesquiterpenes, stereumin F (1) and stereumin G (2), together with two known compounds (3β,5α,22E,24R)‐5,8‐epidioxyergosta‐6,22‐dien‐3‐ol (3) and 4‐(2‐hydroxyethyl)phenol (4), were isolated from the AcOEt extract of the culture broth and the MeOH extract of the mycelium of the fungal strain Stereum sp. CCTCC AF 207024. Their structures were established on the basis of spectral analyses.
Study on the Constituents of Roots of Aceriphyllum rossii
Authors: Kim Van Le Thi , Hung Tran Manh , Kim Soo Hyun , Kim Jin Cheol , Na MinKyun , Jung Hyun Ju , Kwack Seung Jun , Kweon Kee Tae , Choi Jae Sue , Lee Hyeong Kyu , Bae KiHwan , Min Byung‐Sun 
Published: September 2010

AbstractA new stereoisomer of a tetrahydrofuranoid lignan, acerifuranoid A (1), and two new oleanane‐type triterpenoids, aceriphyllic acids J and K (2 and 3), were isolated from the roots of Aceriphyllum rossii. Their structures were elucidated on the basis of spectroscopic analyses and chemical evidence. These isolated compounds exhibited weak cytotoxic activity against various cancer cell lines with IC50>150 μM.
Two New Sesquiterpene Polyol Esters from Celastrus angulatus
Authors: Wei Shao‐Peng , Wu Wen‐Jun , Ji Zhi‐Qin , Zhang Ji‐Wen , Guo Yong‐Ze , Xue Jian 
Published: September 2010

AbstractTwo novel sesquiterpene polyol esters with a dihydro‐β‐agarofuran (=(3R,5aS,9R,9aS)‐octahydro‐2,2,5a,9‐tetramethyl‐2H‐3,9a‐methano‐1‐benzoxepin) skeleton, (1α,2α,4β,8α,9α)‐1,2,8,12‐tetrakis(acetyloxy)‐9‐(furoyloxy)‐4‐hydroxydihydro‐β‐agarofuran (1) and (1α,2α,6β,8α,9α)‐1,2,6,8,12‐pentakis(acetyloxy)‐9‐(benzoyloxy)dihydro‐β‐agarofuran (2), and the three known compounds (1α,2α,4β,6β,8α,9β)‐1,2,6‐tris(acetyloxy)‐9‐(benzoyloxy)‐4‐hydroxy‐8,12‐bis(isobutyryloxy)dihydro‐β‐agarofuran (3), (1α, 2α,4β,6β,8α,9β)‐1,2,6,8‐tetrakis(acetyloxy)‐9‐(furoyloxy)‐4‐hydroxy‐12‐isobutyryloxy)dihydro‐β‐agarofuran (4), and (1α,2α,4β,6β,8α,9β)‐1,2,6‐tris(acetyloxy)‐9‐(benzoyloxy)‐4‐hydroxy‐8‐(isobutyryloxy)‐12‐[(2‐methylbutanoyl)oxy]dihydro‐β‐agarofuran (5) were isolated from the root bark of Celastrus angulatus. Their chemical structures were elucidated by analyses of their MS and NMR data.