bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maximized achievable rate of SINR‐measurement‐based spectrum sharing with binary feedback
Authors: Wang Hanho , Ko Kyunbyoung , Woo Choongchae 
Published: May 2011

SUMMARYMotivated by the difficulty in measuring channel state information between heterogeneous primary and secondary systems, we propose a signal‐to‐interference‐noise ratio (SINR)‐based spectrum sharing policy. In the proposed spectrum sharing policy, a secondary user who does not cause SINR outage at the primary receiver is admitted to share the primary user's spectrum. In this article, we analyze the achievable rate of a secondary user and for whom the achievable rate is maximized in the SINR‐constrained spectrum sharing. The maximized achievable rate is determined by the ratio of the distance between the secondary transmitter and the primary receiver to the distance between the secondary transmitter and receiver, and it is proportional to the distance ratio. In conclusion, secondary links with large distance ratio can support high data rate applications so long as SINR constraint of the primary user is guaranteed. Copyright © 2011 John Wiley & Sons, Ltd.
Methomyl Detection by Inhibition of Laccase Using a Carbon Ceramic Biosensor
Authors: Cadorin Fernandes Suellen , Cruz Vieira Iolanda , Barbosa Antonio Marcos Jacques , Souza Ferreira Valdir 
Published: May 2011

AbstractA sol–gel derived carbon ceramic biosensor was used for methomyl determination in vegetable extract samples based on the immobilization of laccase from Aspergillus oryzae. Esculetin was chosen as the substrate for laccase in order to measure inhibition by this pesticide. The analytical curve was linear for methomyl concentrations of 0.5 to 12.2 µM with a detection limit of 0.2 µM. The lifetime of the proposed biosensor was 60 days and the recovery from vegetable extract samples ranged from 98.0 to 104.2 %. The results using the proposed method are in agreement with those using HPLC at the 95 % confidence level.
Electrochemical DNA Hybridization Assay: Enzyme‐Labeled Detection of Mutation in p53 Gene
Authors: Gupta Gautam , Atanassov Plamen 
Published: May 2011

AbstractThis paper discusses a new electrochemical DNA hybridization sensing approach based on the detection of a linked enzyme label. In this method we employ enzyme that is attached to a tethered ssDNA oligomer on the surface and the target analyte is a complementary ssDNA oligomer that does not require any pre‐treatment. The advantage of using of enzyme label is in its amplification of the registration of the hybridization event due to the catalytic reaction facilitated in the process. One particular novelty is associated with the use of enzymes that directly communicate with the electrode surface thus allowing for minimizing the need of additional reagents in the assay. The electrochemical assay was demonstrated when using mixed self‐assembled monolayers from thiolated oligonucleotide and 6‐mercapto 1‐hexanol on gold surfaces. Horseradish peroxidase (HRP) is attached to the surface tethered oligonucleotide using streptavidin‐biotin chemistry, and the enzyme successfully established direct electron transfer (DET) with the electrode or mediated electron transfer (MET) using a mediator. Hybridization results in increasing the angle of contact between electrode and DNA and also the stiffness of the ds DNA, which results in displacing the enzyme away from the electrode surface, and thereby reducing the occurrence of direct electron transfer between the enzyme and the electrode. The cyclic voltammetry showed a clear distinction in response between the complete complementary sequence and the two‐base mismatch sequence. Ellipsometric measurements show that the thickness of the thiol modified oligonucleotide on gold surfaces changes before and after hybridization for the complementary sequence, where as a minimal change in thickness was observed for the noncomplementary sequence. The model target analyte in this study was TP53 gene where a specific mutation is a marker for a list of cancers. Mutations of the TP53 gene have been demonstrated in tumors of the colon, breast, lung, ovary, bladder, and many other organs. Analysis of p53 mutations may provide useful information for the diagnosis, prognosis and therapy of cancer.
Enhanced Electron Transfer Rates by AC Voltammetry for Ferrocenes Attached to the End of Embedded Carbon Nanofiber Nanoelectrode Arrays
Authors: Syed Lateef U , Liu Jianwei , Prior Allan M. , Hua Duy H. , Li Jun 
Published: May 2011

AbstractThe effect of the interior structure of carbon nanomaterials on their electrochemical properties is not well understood. We report here the electron transfer rate (ETR) of ferrocene (Fc) molecules covalently attached to the exposed end of carbon nanofibers (CNFs) in an embedded nanoelectrode array. The ETR in normal DC voltammetry was found to be limited by the conical graphitic stacking structure interior of CNFs. AC voltammetry, however, can cope with this intrinsic materials property and provide over 100 times higher ETR, likely by a new capacitive pathway. This provides a new method for high‐performance electroanalysis using CNF nanoelectrodes.
Voltammetric Discrimination of DNA Single Base‐Pair Mismatches via Taq DNA Ligase‐Based Mismatch Recognition
Authors: Kim Jun Myung , Koo Chong Min , Kim Joohoon 
Published: May 2011

AbstractAn electrochemical approach for single base‐specific detection of label‐free target single‐strand DNA (ssDNA) was demonstrated. The approach was based on the high ligation selectivity of Taq DNA ligase coupled with ferrocenated gold nanoparticle/streptavidin conjugate‐based voltammetric detection method. The ferrocene (Fc) moieties of Fc‐capped gold nanoparticle/streptavidin conjugates, which were selectively bound to the biotinylated DNA layer, were found to be close enough to the underlying electrode surface for facile electron transfer. The proposed electrochemical method was evaluated with label‐free target DNA strands making all possible base pair combinations at the 3′‐OH side of capture probe, and showed significant voltammetric signals only with a perfect match target strand.
Electrochemical Determination of Cu(II) Ions by 4‐Formylphenylboronic Acid Modified Gold Electrode
Authors: Oztekin Yasemin , Ramanaviciene Almira , Ramanavicius Arunas 
Published: May 2011

AbstractA self‐assembled monolayer (SAM) modified by 4‐formylphenylboronic acid was formed on the gold electrode, which was applied for the determination of trace concentrations of Cu(II). The formation of advanced SAM on the gold electrode was evidenced by electrochemical impedance spectroscopy, atomic force microscopy and contact angle measurements. Electrochemical determination of Cu(II) ions was performed by square wave voltammetry. Some mutual interferences caused by Cd(II), Co(II), Fe(II), Ni(II) and Pb(II) ions were investigated and it was demonstrated how the negative effects of these interfering ions could be eliminated by adjustment of proper parameters of square wave voltammetry.
Facile Synthesis of Pd Nanoparticle Modified Carbon Black for Electroanalysis: Application to the Detection of Hydrazine
Authors: Panchompoo Janjira , Aldous Leigh , Downing Clive , Crossley Alison , Compton Richard G. 
Published: May 2011

AbstractCarbon black nanoparticles modified with palladium nanoparticles (Pd/CB) were prepared using a facile methodology. Stirring CB in an aqueous solution of palladium chloride was found to result in the spontaneous formation of Pd nanoparticles on the CB surface. The Pd/CB composite demonstrated high electrocatalytic activity towards hydrazine oxidation, with good stability and reproducibility. Three linear dynamic ranges of hydrazine determination were found between 5 µM and 50 mM. The limit of detection (LOD) for hydrazine was found to be 8.8 µM (based on 3σ). The sensitivity of unmodified CB to trace metal impurities present in certain common electrolytes is also noted.
A New Electrochemical Biosensor for Determination of Hydrogen Peroxide in Food Based on Well‐Dispersive Gold Nanoparticles on Graphene Oxide
Authors: Zhang Bing , Cui Yuling , Chen Huafeng , Liu Bingqian , Chen Guonan , Tang Dianping 
Published: May 2011

AbstractHerein, we describe a new method for the detection of hydrogen peroxide (H2O2) in food by using an electrochemical biosensor. Initially, ultrafine gold nanoparticles dispersed on graphene oxide (AuNP‐GO) were synthesized by the redox reaction between AuCl4− and GO, and thionine‐catalase conjugates were then assembled onto the AuNP‐GO surface on a glassy carbon electrode. With the aid of the AuNP‐GO, the as‐prepared biosensor exhibited good electrocatalytic efficiency toward the reduction of H2O2 in pH 5.8 acetic acid buffer. Under optimal conditions, the dynamic responses of the biosensor toward H2O2 were achieved in the range from 0.1 µM to 2.3 mM, and the detection limit (LOD) was 0.01 µM at 3sB. The Michaelis–Menten constant was measured to be 0.98 mM. In addition, the repeatability, reproducibility, selectivity and stability of the biosensor were investigated and evaluated in detail. Finally, the method was applied for sensing H2O2 in spiked or naturally contaminated samples including sterilized milk, apple juices, watermelon juice, coconut milk, and mango juice, receiving good correspondence with the results from the permanganate titration method. The disposable biosensor could offer a great potential for rapid, cost‐effective and on‐field analysis of H2O2 in foodstuff.
The computation of the eddy along the upper wall in the three‐dimensional flow over a backward‐facing step
Authors: Malamataris N.A. , Löhner R. 
Published: May 2011

SUMMARYA three‐dimensional laminar flow over a backward‐facing step is studied as a numerical experiment by solving the steady‐state, isothermal and incompressible Navier–Stokes equations using two different finite element codes. The Reynolds number ranges from 100 to 1050. The expansion ratio is 1:1.94, and the aspect ratio is 1:36.7. The numerical experiment reveals both eddies along the lower and upper walls downstream of the step. Results of computations regarding positions of detachment of the eddy along the upper wall and positions of reattachments of the eddies along both the lower and upper walls are tabulated along with positions and magnitudes of global extrema of shear rate within the eddies. The wall effects are shown by calculating streamlines along planes parallel/normal to the lateral walls of the domain and depicting how the streamlines are distorted close to the walls and how they assume a two‐dimensional configuration in the plane of symmetry. Comparisons are made with available numerical results and laboratory measurements. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and Characterisation of Novel Composites Based on a Radiation Grafted Membrane for Fuel Cells
Authors: Çilingir Doğan H. D. , Alkan Gürsel S. 
Published: May 2011

AbstractNovel composites for fuel cells were prepared via two different methods using a radiation grafted membrane, prepared from poly(ethylene‐alt‐tetrafluoroethylene) (ETFE) and styrene, and commercial Nafion®112 as the substrates. The first method was based on chemical polymerisation of pyrrole (Py) on the membrane followed by platinum (Pt) deposition by chemical reduction. The second method was based on direct deposition of Pt on the membrane by several steps of initial composite formation and surface electrodeposition. Polypyrrole (PPy) was coated as a layer only on the surface of the membrane. The thickness of PPy layer, proton conductivity of the composites and Pt loading could be controlled with Py polymerisation time. Moreover, the deposition of Pt on the surface as the granular particles was achieved by the first method while Pt deposition occurred as the aggregates of particles on the surface of the membrane by the second method which yielded wavy and rough surfaces. The first method offered a simple, quick, reproducible and effective procedure, yet some of the Pt particles peeled off from the surface of the composites. The second method required complex, multistep and tedious procedure with a high amount of Pt precursor, while Pt particles were more stable in this case.
Dynamics of Emerging Water Droplet Subjected to Sidewall with Different Wettabilities in a Fuel Cell Cathode Channel
Authors: Zhu X. , Sui P. C. , Djilali N. , Liao Q. 
Published: May 2011

AbstractOn‐site experiments on low temperature fuel cells revealed that water droplets tend to emerge into the gas channel at the corner. This motivates the present investigation on the effects of the location where water emerges from and the wettability of sidewall on the dynamic behaviour of liquid water in gas channel by numerical simulations that employ the volume‐of‐fluid method. A microchannel with a square cross‐section of 0.25 mm in width and a pore of 0.05 mm in diameter is adopted. The simulation results for different pore locations and wettabilities of sidewall show that the behaviour of water droplet only depends on the wettability of bottom wall when it emerges from the centreline without attaching to the sidewall and gains the highest pressure drop. When the emergence location shifts towards the corner, the water droplet unavoidably attaches to the sidewall and thus the wettability of sidewall is found to have significant effects on its dynamics: hydrophobic sidewall results in droplet detachment and fast removal with the highest pressure drop and the minimal water saturation, whereas hydrophilic sidewall leads to a water film and accumulation with the lowest pressure drop and the minimal water coverage on the bottom wall.
Association between the prevalence of depression and age in a large representative German sample of people aged 53 to 80 years
Authors: Wild Beate , Herzog Wolfgang , Schellberg Dieter , Lechner Sabine , Niehoff Doro , Brenner Hermann , Rothenbacher Dietrich , Stegmaier Christa , Raum Elke 
Published: May 2011

ObjectiveThe aim of the study was to determine the association between the prevalence of clinically significant depression and age in a large representative sample of elderly German people.MethodsIn the second follow‐up (2005–2007) of the ESTHER cohort study, the 15‐item geriatric depression scale (GDS‐15) as well as a sociodemographic and clinical questionnaire were administered to a representative sample of 8270 people of ages 53 to 80 years. The prevalence of clinically significant depression was estimated using a GDS cut‐off score of 5/6. Prevalence rates were estimated for the different age categories. Association between depression and age was analyzed using logistic regression, adjusted for gender, co‐morbid medical disorders, education, marital status, physical activity, smoking, self‐perceived cognitive impairment, and anti‐depressive medication.ResultsOf the participants, 7878 (95.3%) completed more than twelve GDS items and were included in the study. The prevalence of clinically significant depression was 16.0% (95%CI = [15.2; 16.6]). The function of depression prevalence dependent on age group showed a U‐shaped pattern (53–59: 21.0%, CI = [18.9; 23.3]; 60–64: 17.7%, CI = [15.7; 19.7]; 65–69: 12.6%, CI = [11.2; 14.0]; 70–74: 14.4%, CI = [12.6; 16.0]; 75–80: 17.1%, CI = [14.9; 19.4]). Adjusted odds ratios showed that the chances of being depressive decrease with the age category but remain relatively stable for people aged 65 and over.ConclusionsThe prevalence of depression in the elderly seems to be associated with the age category. Adjusted odds ratios showed that people aged 60 and older had lower chances of being depressive than people aged 53 to 59 years. Copyright © 2011 John Wiley & Sons, Ltd.
The reaction of (N‐isocyanimino) triphenylphosphorane with (E)‐3‐aryl‐2‐ propenoic acid derivatives: One‐pot synthesis of 2‐[(E)‐2‐aryl‐1‐ethenyl]‐1,3,4‐oxadiazoles via intramolecular aza‐Wittig reaction
Authors: Ahankar Hamideh , Ramazani Ali , Amini Issa , Ahmadi Yavar , Souldozi Ali 
Published: May 2011

AbstractThe reaction of (E)‐3‐aryl‐2‐propenoic acid derivatives with (N‐isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford the corresponding 2‐[(E)‐2‐aryl‐1‐ethenyl]‐1,3,4‐oxadiazole via an intramolecular aza‐Wittig reaction in good yields under neutral conditions. The structures of the products were deduced from their IR, 1H NMR, and 13C NMR spectra and mass spectrometry. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:612–616, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20701
Alkylation of SH‐heterocycles with diethyl phosphite using tetrachloroethylene as an efficient solvent
Authors: Quan Zheng‐Jun , Ren Rong‐Guo , Da Yu‐Xia , Zhang Zhang , Wang Xi‐Cun 
Published: May 2011

AbstractTreatment of mercapto‐heterocyclic compounds with diethyl phosphite in the presence of 4‐dimethylaminopyridine (DMAP) in tetrachloroethylene has given the S‐ethylated product in good yields and high chemoselectivity. This procedure is compatible with a wide range of SH‐compounds such as 1,3,4‐oxadiazole‐2‐thiol, 1,3,4‐thiadiazole‐2‐thiol, benzo[d]thiazole‐2‐thiol, and substituted benzenethiol. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:653–658, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20729
Tobacco carcinogen metabolites and DNA adducts as biomarkers in Head and Neck cancer: Potential screening tools and prognostic indicators
Authors: Khariwala Samir S. , Hatsukami Dorothy , Hecht Stephen S. 
Published: May 2011

AbstractHead and neck squamous cell carcinoma (HNSCC) is one of many cancers that are strongly associated with tobacco use. Whereas HNSCC is often seen in tobacco users, many tobacco users do not develop carcinoma; and the differences between smokers with and without HNSCC are poorly studied to date. Some smokers may be inherently more susceptible to developing carcinoma due to patterns of tobacco use, innate metabolism of carcinogens, or altered excretion. Identifying those smokers at greatest risk for HNSCC would have great benefit through targeted smoking cessation efforts and enhanced surveillance. One approach to better understand the extent of exposure to, and metabolism of, tobacco carcinogens is through the use of tobacco‐specific metabolites. Tobacco‐specific metabolites can identify patterns of dose, exposure, and metabolism, and perhaps ultimately characterize the important differences between smokers who develop HNSCC and smokers who do not. © 2011 Wiley Periodicals, Inc. Head Neck, 2012
Experience with local lymph node assay performance standards using standard radioactivity and nonradioactive cell count measurements
Authors: Basketter David , Kolle Susanne N. , Schrage Arnhild , Honarvar Naveed , Gamer Armin O. , van Ravenzwaay Bennard , Landsiedel Robert 
Published: May 2011

ABSTRACTThe local lymph node assay (LLNA) is the preferred test for identification of skin‐sensitizing substances by measuring radioactive thymidine incorporation into the lymph node. To facilitate acceptance of nonradioactive variants, validation authorities have published harmonized minimum performance standards (PS) that the alternative endpoint assay must meet. In the present work, these standards were applied to a variant of the LLNA based on lymph node cell counts (LNCC) run in parallel as a control with the standard LLNA with radioactivity measurements, with threshold concentrations (EC3) being determined for the sensitizers. Of the 22 PS chemicals tested in this study, 21 yielded the same results from standard radioactivity and cell count measurements; only 2‐mercaptobenzothiazole was positive by LLNA but negative by LNCC. Of the 16 PS positives, 15 were positive by LLNA and 14 by LNCC; methylmethacrylate was not identified as sensitizer by either of the measurements. Two of the six PS negatives tested negative in our study by both LLNA and LNCC. Of the four PS negatives which were positive in our study, chlorobenzene and methyl salicylate were tested at higher concentrations than the published PS, whereas the corresponding concentrations resulted in consistent negative results. Methylmethacrylate and nickel chloride tested positive within the concentration range used for the published PS. The results indicate cell counts and radioactive measurements are in good accordance within the same LLNA using the 22 PS test substances. Comparisons with the published PS results may, however, require balanced analysis rather than a simple checklist approach. Copyright © 2011 John Wiley & Sons, Ltd.
Histology of tooth attachment tissues and plicidentine inVaranus(Reptilia: Squamata), and a discussion of the evolution of amniote tooth attachment
Authors: Maxwell Erin E. , Caldwell Michael W. , Lamoureux Denis O. , Budney Lisa A. 
Published: May 2011

AbstractFew recent studies have examined the histological basis for tooth attachment in squamates. In the past few years, a surge of interest in this topic has led to the intriguing suggestion that the major tissues derived from the tooth germ (enamel, dentine, cementum and alveolar bone), are conservative and are present in all amniotes. In this study, we describe the histology and development of the tooth attachment complex inVaranus rudicollis, the rough‐neck monitor. We provide the first published evidence for the role of cementum and alveolar bone in tooth attachment in varanoid lizards. InVaranus,cementum is deposited on the external surface of the tooth root as well as at the base of the tooth, where it plays a role in the attachment of the tooth to the jawbone. Alveolar bone is also involved in tooth ankylosis. Our results support the hypothesis that the major tooth germ tissues are found in all amniotes. We provide insights into the structure and development of plicidentine, defined as infolding of the dentine around the tooth base. This feature is unique to varanoids among extant tetrapods and is the third tissue implicated in tooth attachment inVaranus. Plicidentine develops asymmetrically along the labial‐lingual axis of a tooth.Varanusis characterized by the presence of both primary and higher‐order lamellae, which anastomose to form a honeycomb‐like surface that then interacts with the more basal attachment tissues. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Bone metastases: Evaluation of acuity of lesions using dynamic gadolinium‐chelate enhancement, preliminary results
Authors: Northam Meredith , de Campos Rafael O.P. , Ramalho Miguel , Heredia Vasco , Gonzalez Carlos A. , Azevedo Rafael M. , Semelka Richard C. 
Published: May 2011

AbstractPurpose:To evaluate whether enhancement on serial dynamic gadolinium‐enhanced abdominal–pelvic MR imaging (DCE‐MRI) can determine the acuity of bone metastases.Materials and Methods:Twenty consecutive patients who underwent abdominal–pelvic DCE‐MRI for evaluation/staging of a proven cancer and had bone metastases were included. Two radiologists analyzed in consensus 59 DCE‐MRIs of these patients. Region of interest measurements were performed in up to three lesions on noncontrast T1‐weighted, serial hepatic arterial dominant phase (HADP), early hepatic venous phase (EHVF), and interstitial phase (IP) postgadolinium images, and the percentage enhancement of 134 lesions was calculated. The coordinator separately and retrospectively sorted the lesions into three groups based on the imaging and clinical information: acute/active, subacute, and chronic metastases.Results:The mean percentage enhancement of the bone metastases classified as acute/active, subacute, and chronic in the HADP, EHVP and IP were respectively (%): 134, 107, 99; 87, 86, 87; and 39, 65, 73. In the HADP, acute/active lesions enhanced significantly more than both subacute (1.53‐fold) and chronic (3.4‐fold) lesions (P < 0.01). Time intensity curves were significantly different between these three entities as well.Conclusion:The enhancement on arterial phase images and the time–intensity curves were different for acute/active, subacute, and chronic bone metastases. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.