bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Interaction of Vitamin B12 with DNA by Spectroscopy and Electrochemical Methods
Authors: Hajian Reza , Zafari Mitra
Published: July 2011

The Interaction between vitamin B12 (VB12) and fish sperm DNA was investigated in physiological buffer (pH 7.4) using the methylene blue (MB) dye as a spectral probe by spetcrophotometery, viscosity measurements and cyclic voltammetry. The apparent binding constant of vitamin B12 with DNA was found to be 3.2×105 mol−1·L. The voltammetric behavior of vitamin B12 has been investigated at glassy carbon electrode using cyclic voltammetry. Thermodynamic parameters including ΔH0, ΔS0 and ΔG0 for the interaction between VB12 and DNA have determined as −2.3×104, 27.54 and −3.1×104J·mol−1·K−1 respectively. One indication of DNA binding mode with VB12 was the change in viscosity when a small molecule associates with DNA. The diffusion coefficients of VB12 in the absence (D0)f and presence of DNA (D0)b was calculated as 5.04×10−6 and 1.13×10−6 cm2·s−1 respectively. The results indicated that vitamin B12 can bind to DNA and the major binding mode was intercalative binding.
Thermal Decomposition Kinetics of Some Di‐ and Triorganotin(IV) Carboxylates Derived from para‐Nitrophenylethanoic Acid
Authors: Danish Muhammad , Ahmad Nazir , Ali Saqib , Muhammad Niaz
Published: July 2011

Thermogravimetric (TG) investigations of organotin(IV) carboxylates with the general formula RmSnL4−m (where R=CH3, C2H5, n‐C4H9, C6H5, cyclo‐C6H11, n‐C8H17, m=2, 3, and L=para‐nitrophenylethanoate anion) have been performed. Derivative thermogravimetry (DTG) and differential thermal analysis (DTA) techniques, Horowitz‐Metzger method and the fundamental thermodynamic relations are used to evaluate the thermokinetic parameters of each thermal degradation pattern. Results reveal that the thermal stability is functional to SnC and SnO bonds. In the case of R2SnL2, activation energy, reaction order and pre‐exponential factor associated with the bulk degradation processes increase as the alkane chain length increases. Hence, Oct2SnL2 is thermally more stable than Bu2SnL2, which in turn is more resistant to thermal dissociation than Et2SnL2. The same phenomenon is not observed for R3SnL compounds because their degradation is highly irregular. Furthermore, R2SnL2 has larger values of kinetic parameters than those of corresponding triorganotin(IV) para‐nitrophenylethanotes. Thermodynamic parameters of these compounds also reinforce the above facts.
First Hyperpolarizability Evolutions of Some Extended Sesquifulvalene Compounds
Authors: Mang Chaoyong , Liu Caiping , Yang Zhiyi , Peng Li , Wu Kechen
Published: July 2011

Molecular orbital calculations of some extended sesquifulvalene compounds as On with olefins bridge and Tn with thiophenes bridge as well as their corresponding cyclopentadienyl‐iron(II) coordination compounds as IOn and ITn at the hybrid density functional theory level demonstrate that the dipole moment depends linearly on the molecular size (n), and the linear polarizability depends linearly on n2 as well as the first hyperpolarizability also has a linear dependence on n3.
Synthesis, Structure and Photoluminescent Properties of Zn(II)/Cd(II)‐Complexes Containing 2,4,6‐Tris‐(benzimidazolyl‐2‐yl)pyridine Ligand
Authors: Li Cuijin , Guo Qingbing , Yin Guoqiang , Jiang Xuhong , Gong Sheng
Published: July 2011

Hydrothermal reactions of tridentate rigid 2,4,6‐tris‐(benzimidazolyl‐2‐yl)pyridine (pytbzim) ligand and Zn(II)/Cd(II) salts generate binuclear complexes {[Cd2Cl2(pytbzim)2(H2O)2]·2NO3}n (1) and two isomorphs {[M2Cl2(pytbzim)2(H2O)2]Cl2·2H2O}n [M=Cd (2), Zn (3)]. All complexes include [M2Cl2(pytbzim)2(H2O)2] dimers, which are further connected into a three‐dimensional supramolecular networks through ?‐? stacking interaction and hydrogen bonds. The solid state photoluminescent studies reveal good fluorescent properties of the pytbzim ligand and complexes 1–2 at room temperature.
A Rapid Synthesis of Pyranoid Glycals Promoted by β‐Cyclodextrin and Ultrasound
Authors: Zhao Jinzhong , Shao Huawu , Wu Xin , Shi Shaojing
Published: July 2011

A convenient and environmentally benign procedure for the synthesis of glycals from glycosyl bromides with very low zinc dust loading (1.5 equiv.) is described. The process is activated by β‐cyclodextrin and ultrasound. Based on 19 samples, this method has been demonstrated to be highly effective for a broad range of glycosyl bromides, including acid‐ or base‐sensitive and disaccharide glycosyl bromides. A yield of 85%–96% of glycals was obtained.
Cyclization of 4,5‐Diamino Pyrazole Derivatives and Their Antibacterial Activities
Authors: Rizk Hala F. , EI‐Badawi Mahmoud A. , Ibrahim Seham A. , EI‐Borai Mohamed A.
Published: July 2011

A convenient synthesis of intermediate 4,5‐diamino‐3‐aryl‐1‐phenylpyrazoles 4a–4c was reported. The different cyclization reactions were carried out with chalcone, 2‐mercaptoacetic acid and p‐anisialdehyde, ethyl chloroformate, glyoxal and thiourea to afford different N and S containing heterocycles. The reaction conditions were compared by conventional heating and microwave irradiation. The structures of the cyclization products were determined by analytical and spectroscopic data. All the synthesized compounds were screened for antibacterial activities in vitro.
Synthesis and Supramolecular Assemblies of Tripodal 1,3,5‐Tris(phenoxymethyl)‐2,4,6‐triethylbenzene Analogues
Authors: Ma Mingliang , Kong Lingwei , Li Xiaoyan , Jin Haishan , Zhao Xiaoli , Wen Ke
Published: July 2011

Tripodal 1,3,5‐tris(phenoxymethyl)‐2,4,6‐triethylbenzene analogues have been synthesized and structurally characterized by IR, 1H NMR and 13C NMR spectroscopy and HRMS, and additionally, the single crystal structures of compounds bearing ortho‐ (7), meta‐ (9) and para‐hydroxymethyl (11) functions have been determined by X‐ray diffraction analysis. The structural study revealed that compounds 7, 9, and 11 do not adopt the expected 1,3,5‐alternate conformation in the solid state. The packing diagrams of compounds 7, 9, and 11 revealed that six hydrophilic hydroxymethyl groups from six individual molecules (7, 9 and 11) were arranged in close contact via intermolecular hydrogen‐bond interactions. For compounds 7 and 9, the six hydroxyl groups formed a distorted hexagonal ring; however, formation of such a hexagonal ring was not clear in the case of compound 11. Compounds 9 and 11 were found to form hydrophobic cavities via intermolecular hydrogen‐bond interactions in the solid state, and the cavities were occupied by two ethyl groups from the two cavity‐forming molecules.
Synthesis and Characterization of New 3‐(3‐Hydroxyphenyl)‐4‐ alkyl‐3,4‐dihydrobenzo[e][1,3]oxazepine‐1,5‐dione Compounds
Authors: Osman Hasnah , Mohammad AbdulKarim‐Talaq , Yeap Guan‐Yeow , Adam Farook
Published: July 2011

A series of 3‐(3‐hydroxyphenyl)‐4‐alkyl‐3,4‐dihydrobenzo[e][1,3]oxazepine‐1,5‐dione compounds with general formula CnH2n+1CNO(CO)2C6H4(C6H4OH) in which n are even parity numbers from 2 to 18. The structure determinations on these compounds were performed by FT‐IR spectroscopy which indicated that the terminal alkyl chain attached to the oxazepine ring was fully extended. Conformational analysis in DMSO at ambient temperature was carried out for the first time via high resolution 1H NMR and 13C NMR spectroscopy.
Quantitative Analysis of Holmium Ion by a Ho3+ Ion‐Selective Sensor Based on a Symmetric Thio‐Schiff's Base
Authors: Zamani Hassan Ali , Fatemeh Rahimi , Fatemeh Naghavi‐Reyabbi , Ali Arvinfar , Alihossien Imani , Mohammad Reza Ganjali , Farnoush Faridbod , Masoud Salavati‐Niasari
Published: July 2011

A poly(vinyl chloride) (PVC) membrane sensor for holmium ions was fabricated based on N‐[(Z)‐1‐(2‐thienyl)‐ methylidene]‐N‐[4‐(4‐{[(Z)‐1‐(2‐thienyl)methylidene]amino} phenoxy)phenyl] amine (TPA) as a new ion carrier, acetophenon (AP) as plasticizing solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. The electrode shows a good selectivity towards Ho3+ ions respect to other inorganic cations, including alkali, alkaline earth, transition and heavy metal ions. The constructed sensor displays a Nernstian behavior (19.5±0.3 mV/decade) over the concentration range of 1.0×10−6 to 1.0×10−2 mol·L−1 with the detection limit of the electrode being 4.6×10−7 mol·L−1 and very short response time (ca. 5 s). It has a useful working pH range of 3.2–9.8 for at least 8 weeks. The electrode was successfully applied as an indicator electrode for the potentiometric titration of a Ho3+ solution with EDTA and holmium determination in some alloys. The proposed sensor accuracy was studied by the determination of Ho3+ in mixtures of three different ions.
Novel Hydrazone‐Based Tripodal Sensors: Single Selective Colorimetric Chemosensor for Acetate in Aqueous Solution
Authors: Zhang Youming , Li Qiao , Zhang Qinsheng , Lin Qi , Cao Cheng , Liu Mingxia , Wei Taibao
Published: July 2011

A series of novel tripodal colorimetric anion sensors based on hydrazone CHNNH groups have been synthesized and their recognition behavior with anionic guests has been studied. In DMSO solutions, sensors 1 and 2 show colorimetric responses for F−, H2PO−4 and AcO−, while in DMSO/H2O (9:1, V/V) solutions, sensor 1 shows single selectivity for AcO−. 1H NMR titration confirms that the tripodal sensors could bind anions through the collaboration of three hydrazone groups and anions residing in the central cavity of the sensors.
Determination of Astaxanthin and Canthaxanthin Triplet Properties in Different Polarities of the Solvent by Laser Flash Photolysis
Authors: Li Haixia , Zhang Peng , Song Xiyu , Wang Wenfeng
Published: July 2011

Triplet‐triplet extinction coefficients for astaxanthin (I) and canthaxanthin (II) in different deaerated polarity solutions of MeCN and benzene were evaluated by laser flash photolysis at 298 K in the spectral region from 350 to 650 nm by energy transfer method, employing 2‐acetonaphthone as sensitizer. The triplet‐triplet extinction coefficients in MeCN and benzene were different in terms of the carotenoid present. The maximum triplet‐triplet extinction coefficient was 0.1–1.7×105 L·mol−1·cm−1 in different solvents. The rate constants of triplet decay were I: 1.25×1010 L·mol−1·s−1, II: 1.12×1010 L·mol−1·s−1 in MeCN; and I: 1.75×1010 L·mol−1·cm−1, II: 3.27×1010 L·mol−1·s−1 in benzene. The bimolecular rate constants of energy transfer from triplet excited 2‐acetonaphthone to carotenoids were determined from the linear regression of the decay rate constant of 2‐acetonaphthone triplet at varying carotenoid concentrations. The triplet lifetimes of 3AST* and 3CAN* in different solvents were also determined. The results indicated that triplet energy transfer was nearly diffusion‐controlled.
Effect of Lead Contamination on Soil Microbial Activity Measured by Microcalorimetry
Authors: Gai Nan , Yang Yongliang , Li Tao , Yao Jun , Wang Fei , Chen Huilun
Published: July 2011

Microcalorimetry was used to investigate the microbial activity in three types of soil (orchard soil, crop soil, forest soil) in Wuhan, China, and to evaluate the influence of different concentrations of lead (Pb2+) on soil microbial activity. The experimental results revealed that due to different physical and chemical characteristics of the soils, soil microbial activity in three soil samples were in a descending sequence: orchards soil, crops soil, forest soil. Six levels of Pb viz. 0, 10, 20, 40, 80, 160 μg·g−1 were applied in these soils, and the results showed that an increase of the amount of Pb2+ is associated with a decrease in microbial activity in the soils due to the toxic effect of Pb2+. In order to gain further insight of the sequential change of microorganisms, determination of colony forming units (CFU) was performed to provide a negative linear correlation between the heat effect and the respective number of microorganisms in the system.
Fitting regression models with response‐biased samples
Authors: Scott Alastair J. , Wild Chris J.
Published: July 2011

This paper extends the work in Lawless, Kalbfleisch, & Wild (1999) on fitting regression models with response‐biased samples, that is, samples where some or all the covariates are missing for some units and the probability that this happens depends in part on the value of the reponse of that unit. In general, the resulting likelihood depends on the distribution of the covariates but we are only interested in methods that do not involve modelling this distribution. We look at a variety of methods based on estimating equations, at the relationship of these methods to semi‐parametric efficient methods in cases where such methods exist, and show ways of obtaining efficiency gains that can sometimes be dramatic. The Canadian Journal of Statistics 39: 519–536; 2011 © 2011 Statistical Society of Canada
Optimal estimating functions in incomplete data and length biased sampling data problems
Authors: Qin Jing , Zhang Biao
Published: July 2011

It is well known that the score function is the optimal estimating function among all regular unbiased estimating functions (Godambe, 1960). In the presence of incomplete data such as missing data or length biased sampling data, Horvitz and Thompson's (1952) method is an effective way of eliminating the possible bias induced by using complete data only. In this article, we show that the inverse weighted Horvitz and Thompson score estimating function is not optimal in the presence of incomplete data. By using Godambe's estimating function theory, we can identify the optimal estimating function in this situation. In the case of the accelerated failure time model with length bias sampling data, the optimal estimating function can produce an unbiased estimator for the slope parameter even when the underlying density function is misspecified. Simulation studies show that the estimate derived from the optimal estimating function can be substantially better than the estimate derived from the inverse weighted score estimating function. The Canadian Journal of Statistics 39: 510–518; 2011 © 2011 Statistical Society of Canada
Retinal remodeling in the Tg P347L rabbit, a large‐eye model of retinal degeneration
Authors: Jones Bryan William , Kondo Mineo , Terasaki Hiroko , Watt Carl Brock , Rapp Kevin , Anderson James , Lin Yanhua , Shaw Marguerite Victoria , Yang Jia‐Hui , Marc Robert Edward
Published: July 2011

A oblique section through the bipolar cell layer and partial outer plexiform layer (upper left) of a TgP347L rabbit retina early in the degenerative process visualized with sQE :: rgb mapping. At 12–16 weeks, the TgP347L rabbit retina still has photoreceptors, but Müller cell signatures in yellow/orange can be seen indicating early altered metabolic profiles prior to glial hypertrophy. Bipolar cells are functionally switching their phenotypes at this stage as revealed by glutamate channel expression changes and AGB permeation of activated iGluRs, but appear retain their formal small molecular phenotype at this stage. The Journal of Comparative Neurology, Volume 519, Number 14, pages 2713–2733. J. Comp. Neurol., 2011. © 2011 Wiley‐Liss, Inc.
Physical appearance as a measure of social ranking: The role of a new scale to understand the relationship between weight and dieting
Authors: Ferreira Cláudia , Pinto‐Gouveia José , Duarte Cristiana
Published: July 2011

This study presents the development of a new self‐report instrument to assess how an individual perceives himself as social agent within his group having physical appearance as a reference, the Social Comparison through Physical Appearance Scale (SCPAS). This scale adds to the existent measures by assessing the social ranking based on one's physical appearance, and not the tendency to make comparisons of the general physical appearance or specific body parts. Its psychometric characteristics are investigated in a sample of 828 female participants from normal population. Principal components analysis was conducted for each part of the instrument: the Part A: peers shows a 2‐factor structure (Attractiveness/Rank and Group Fit) explaining 72.142% of the variance; the Part B: models presents a one‐dimensional structure that explains 69.191% of the variance. Findings show very good internal consistency coefficients and test‐retest reliability. The two parts of the SCPAS are significantly associated to social comparison and shame measures, to anxiety, depression and stress indicators, and to eating disorders symptomatology. The scale discriminates between a clinical sample of 91 patients with an eating disorder and a non‐clinical sample of 102 participants. Regression analyses pointed out that social comparison through physical appearance with peers and models partially mediates the effect of the dissatisfaction with current weight on disordered eating, namely drive for thinness. Copyright © 2011 John Wiley & Sons, Ltd.

Key Practicioner Message

The SCPAS is a new self‐report questionnaire for assessing social ranking evaluation through the subjective comparison of physical appearance with others.

The SCPAS is a brief measure with very good internal consistency, test‐retest reliability, convergent and divergent validity, and it shows a satisfactory accuracy for discriminating between eating disorder patients and non‐clinical participants.

Findings suggest that disordered eating, namely dieting and thinness seeking, does not directly result from body image dissatisfaction, and other processes, such as perceptions of a low social rank that derive from appearance‐based comparisons, are probably involved.
Multiphoton flow cytometry strategies and applications
Authors: Tkaczyk Eric R. , Tkaczyk Alan H.
Published: July 2011

A handful of research teams around the world have recently begun to utilize multiphoton techniques in cytometry, especially for in vivo applications. These approaches offer similar enhancements to flow cytometry as the multiphoton phenomenon brought to the field of microscopy at the turn of the 20th century, with at least six advantages over single‐photon excitation. Here, we review the published literature on multiphoton cytometry in vivo or in vitro from the initial experiments in 1999 to present. Multiphoton cytometry instrumentation set‐ups vary from adapted multiphoton microscopy to a dedicated system, with laser pulse power and repetition rate serving as important variables. Two‐beam geometry enables quantitation of cell size. Labeling strategies include conjugated fluorophore targeting, with folate and/or dendrimer platforms. With two‐color measurement, ratiometric labeling is also possible, where one dye serves as a trigger to indicate the amount of excitation a cell receives, and another informs of cellular function. With two‐color labeling, geometric fluorophore distribution proves important in theory and experiment for detection sensitivity curves and detected event intensity correlation. The main biological achievements to date using this young technology are reviewed, with emphasis on real‐time monitoring of minute‐by‐minute and long‐term cell dynamics as well as the clinically significant surveillance of circulating tumor cells. For this goal, minimally invasive two‐photon flow cytometry with a fiber probe may overcome the primary issue of sample volume. The technique of multicolor, multiphoton flow cytometry greatly enhances the capabilities of flow cytometry to investigate the dynamics of circulating cells in cancer and other important diseases, and may in the future benefit from advances in microscopy such as super‐resolution imaging, coherent control, and bioluminescence. © 2011 International Society for Advancement of Cytometry
Hetastarch reduces neuronal cell death caused by oxidative stress
Authors: Lee Kyu‐Yong , Koh Seong‐Ho , Kim Sangjae , Park Hyun‐Hee , Lee Young Joo
Published: July 2011

We investigated the effect of hetastarch, used for the treatment of acute ischemic stroke, on neuronal cell damage by oxidative stress, a main pathogenic mechanism in ischemic stroke. Neuronally differentiated PC12 cells (nPC12 cells) were treated with varying concentrations of hetastarch and hydrogen peroxide (H2O2), and their viability was measured with a 3,(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and trypan blue staining. The effect of hetastarch on free radical production by H2O2 was evaluated using the fluorescent probe 2′,′‐dichlorodihydrofluorescein diacetate (DCFH‐DA) and by quantifying the amount of 2,5‐ and 2,3‐dihydroxybenzoic acid (DHBA). Additionally, the expression levels of BAX, Bid, Bcl‐2, Bcl‐xL, cytosolic cytochrome c, and cleaved caspase‐3 were examined using Western blot analysis. Following exposure to 100 µM H2O2, the viability of nPC12 cells significantly decreased; however, cell viability increased with hetastarch treatment. Free radical production related to H2O2 exposure was significantly reduced after 100 µM hetastarch treatment. The expression levels of BAX, Bid, cytosolic cytochrome c, and activated caspase‐3 were reduced, whereas Bcl‐2 and Bcl‐xL levels increased in H2O2‐injured nPC12 cells treated with 100 µM hetastarch, as compared with nPC12 cells that were treated with only 100 µM H2O2. These results demonstrate that hetastarch can reduce oxidative stress‐induced neuronal cell death. Drug Dev Res 73: 35–42, 2012. © 2011 Wiley Periodicals, Inc.
Electrostatic Interaction of Negatively Charged Core–Shell Nanoparticles with Antitumoral Cationic Platinum‐Based Complexes (Eur. J. Inorg. Chem. 22/2011)
Authors: Gál Miroslav , Híveš Ján , Laus Michele , Sparnacci Katia , Ravera Mauro , Gabano Elisabetta , Osella Domenico
Published: July 2011

The cover picture shows the electrostatic interaction between a cationic antiproliferative platinum compound cis‐[PtCl(NH3)2(py)]+ and novel poly(methyl methacrylate) core–shell nanoparticles bearing anionic (–SO3–) arms. This interaction was studied by electrochemical techniques to determine whether such particles might serve as drug carriers for Pt drugs. Details on these Pt–nanosphere conjugates can be found in the article by D. Osella et al. on p. 3289 ff.
Iminosugar Analogues of Phosphatidyl Inositol as Potential Inhibitors of Protein Kinase B (Akt)
Authors: Orsato Alexandre , Barbagallo Emanuela , Costa Barbara , Olivieri Sandro , De Gioia Luca , Nicotra Francesco , La Ferla Barbara
Published: July 2011

A small virtual library of iminosugar derivatives was evaluated by docking experiments carried out by sampling a protein region corresponding to the phosphoinositide binding site of the PH domain of Akt. Four compounds were selected and efficiently synthesised from a common precursor. All compounds were subjected to preliminary biological evaluation on purified enzyme, and – among them – compound 9 exhibited the best inhibitory activity.
A Glucose Sensor Based on an Aminophenyl Boronic Acid Bonded Conducting Polymer
Authors: Das Debasmita , Kim Dong‐Min , Park Deog‐Su , Shim Yoon‐Bo
Published: July 2011

3‐Aminophenyl boronic acid (APBA) bonded on the conducting polymer layer was prepared and used for detection of saccharides through the complexation between boronic acid and diol groups of saccharide. The probe was prepared by electropolymerization of 5,2′ : 5,2′′‐terthiophene‐3′‐carboxylic acid (TTCA), followed by covalent bond formation with APBA. It provides the site for the formation of tetrahedral boronate ester on the polymer layer (pTTCA). Each surface was characterized by CV, XPS, and QCM. Results show a dynamic range between 0.9 and 9.1 µM and a detection limit of 0.49 µM for glucose. The sensor was also applied for the detection of other saccharides including galactose and mannose. The performance of the sensor was evaluated in a human saliva sample.
Enhanced Sensitivity of a Galactose Biosensor Fabricated with a Bundle of Conducting Polymer Microtubules
Authors: Lee Kyoung Neung , Lee Youngkwan , Son Yongkeun
Published: July 2011

A bundle of conducting polymer tubules was employed to build a biosensor of improved sensitivity. The tubule structure was able to provide larger enzyme encapsulating space per unit area of the sensor electrode compared to other immobilizing methods. The bundle structure was prepared by using electrochemical polymerization of EDOT into the template on ITO. After dosing of enzyme into the tubule, it was covered with PPDA channels. The amperometric response of the sensor to galactose showed linear behavior in the range of 0.1–1 mM with an average sensitivity of 6.37 µA/mM cm2. The response time was 30–40 s. After keeping the sensor in phosphate buffer solution at 4 °C for a week, it showed about 82 % of its original sensitivity. The detection limit was 0.01 mM based on S/N=3.
Electrochemical Screening of Biomarkers in Chemotype Mexican Oregano Oils on Single‐Walled Carbon Nanotubes Screen‐Printed Electrodes
Authors: Fuentes Fanny González , Gil Miguel Ángel López , Mendoza Sandra , Escarpa Alberto
Published: July 2011

An electrochemical screening for the determination of total biomarkers (thymol and carvacrol) of Lippia graveolens using single‐walled carbon nanotubes screen‐printed electrodes (SWCNT‐SPEs) is proposed. The suitability of the approach was demonstrated using GC‐MS by the analysis of selected Mexican oregano essential oil chemotypes. The analytical performance was excellent in terms of inter‐droplet precision (RSD≤6 %), sensitivity and linearity. An electrochemical index of biomarkers is proposed for fast assessment of oregano quality using just 50 µL of the sample. The route here proposed constitutes a very convenient screening tool in decentralized analysis because of the simplicity, disposability and easy‐to‐use by non‐specialist user.
Formation of a Single Pinhole on Self‐Assembled Monolayer Modified Nanometer‐Sized Gold Electrode and Its Electrochemical Behaviors
Authors: Lakbub Jude , Kady Ismail , Sun Peng
Published: July 2011

In this paper, a nanometer‐sized gold electrode with an effective radius around several tens of nanometers has been modified with a monolayer of alkanethiols. There are pinholes in the monolayer, and the pinholes can be used as very small electrode. Our evaluation shows that it is possible to have only one pinhole on the monolayer covered electrode. The single pinhole electrode has been used to study the electrochemical behaviors of fast and slow electrochemical reactions. Our results show that the electrochemical response of a slow electrochemical reaction is not a Butler–Volmer response if the electrode is small enough.
A novel approach to dielectrophoresis using carbon electrodes
Authors: Martinez‐Duarte Rodrigo , Renaud Philippe , Madou Marc J.
Published: July 2011

Carbon‐electrode dielectrophoresis (carbon‐DEP) is demonstrated here as an alternative to more traditional DEP techniques. Carbon‐DEP combines advantages of metal‐electrode and insulator‐based DEP by using low‐cost fabrication techniques and low voltages for particle manipulation. The use of 3‐D electrodes is proved to yield significant advantages over the use of traditional planar electrodes. This paper details the fabrication of dense arrays of tall high aspect ratio carbon electrodes on a transparent fused‐silica substrate. The shrinkage of the SU‐8 structures during carbonization is characterized and a design tool for future devices is provided. Applications of carbon electrodes in DEP are then detailed and include particle positioning, high‐throughput filtering and cell focusing using positive‐DEP. Manipulated cells include Saccharomyces cerevisiae and Drosophila melanogaster. The advantages and disadvantages of carbon‐DEP are discussed at the end of this work.
Simultaneous analysis of six cardiovascular drugs by capillary electrophoresis coupled with electrochemical and electrochemiluminescence detection, using a chemometrical optimization approach
Authors: Li Xia , Zhu Derong , You Tianyan
Published: July 2011

CE coupled with dual electrochemical (EC) and electrochemiluminescence (ECL) detection was optimized for simultaneous analysis of six cardiovascular drugs (alprenolol, propafenone, acebutolol, verapamil, atenolol and metoprolol) via central composite design. Following this study, three critical electrophoretic factors governing the CE separation were investigated: Tris‐H3PO4 buffer concentration, buffer pH value and separation voltage. A modified chromatographic response was adopted for evaluating CE separation quality. Optimum conditions were achieved using Tris‐H3PO4 buffer 35.6 mM (pH 2.3) separated at 13.9 kV, which was employed experimentally and led to the successful simultaneous separation of the above six drugs. The good agreement of the chromatographic response was observed between predicted data and actual experimental results using these optimized conditions (RSD=3.75%). The proposed method was validated for linearity, repeatability and sensitivity, and subsequently successfully applied to determine six basic drugs in urine samples.
Determination of nicotine and its metabolite cotinine in urine and cigarette samples by capillary electrophoresis coupled with electrochemiluminescence
Authors: Sun Jinying , Du Hongwei , You Tianyan
Published: July 2011

In this paper, CE coupled with electrochemiluminesence (ECL) detection using a 76‐μm Pt disk as working electrode was developed for nicotine (NIC) determination. The major metabolite of NIC is cotinine (COT), which has a similar tertiary amine structure to NIC. However, there is a carbonyl group attached in the structure of COT, which leads to the great decrease in ECL response. In order to improve the ECL response of COT, NaBH4 was used for carbonyl reduction. After reduction, NIC and COT were separated and detected by CE‐ECL. ECL response plotted with NIC concentration was linear between 5.0×10−7 and 5.0×10−5 mol/L (81–8100 μg/L), with LOD of 5.0×10−8 mol/L (8.1 μg/L). The developed CE‐ECL method was applied for NIC determination in urine and cigarette samples.
Dispersive liquid–liquid microextraction coupled with capillary electrophoresis for simultaneous determination of sulfonamides with the aid of experimental design
Authors: Wen Yingying , Li Jinhua , Zhang Weiwei , Chen Lingxin
Published: July 2011

A novel method for the simultaneous determination of sulfonamides (SAs) in water samples has been developed by using dispersive liquid–liquid microextraction (DLLME) coupled with CE. Orthogonal and Box–Behnken designs were employed together to assist the optimization of DLLME parameters, including volumes of extraction and disperser solvents, ionic strength, extraction time, and centrifugation time and speed as variable factors. Under the optimum extraction and detection conditions, successful separation of the five SAs was achieved within 5 min, and excellent analytical performances were attained, such as good linear relationships (R>0.980) between peak area and concentration for each SA from 0.5 to 50 μg/mL, low limits of detection for the five SAs between 0.020 and 0.570 μg/mL and the intra‐day precisions of migration time below 0.80%. The method recoveries obtained at fortified 10 μg/mL for three water samples ranged from 53.6 to 94.0% with precisions of 1.23–5.60%. The proposed method proved highly sensitive and selective, rapid, convenient and cost‐effective, showing great potential for the simultaneous determination of SAs in water samples.
Thermal stabilization of tissues and the preservation of protein phosphorylation states for two‐dimensional gel electrophoresis
Authors: Smejkal Gary B. , Rivas‐Morello Chiara , Chang Jae‐Hyung Robert , Freeman Emily , Trachtenberg Alexander J. , Lazarev Alexander , Ivanov Alexander R. , Kuo Winston P.
Published: July 2011

2‐DE is typically capable of discriminating proteins differing by a single phosphorylation or dephosphorylation event. However, a reliable representation of protein phosphorylation states as they occur in vivo requires that both phosphatases and kinases are rapidly and completely inactivated. Thermal stabilization of mouse cerebral cortex homogenates effectively inactivated these enzymes, as evidenced by comparison with unstabilized tissues where abscissal pI shifts were a common feature in 2‐D gels. Of the 588 matched proteins separated on 2‐D gels comparing stabilized and unstabilized tissues, 53 proteins exhibited greater than twofold differences in spot volume (ANOVA, p<0.05). Phosphoprotein‐specific staining was corroborated by the identification of 16 phosphoproteins by nano‐LC MS/MS and phosphotyrosine kinase activity assay.
Historical floods and dendrochronological dating of a wooden deck in the Old Mint of Segovia, Spain
Authors: Génova Mar , Ballesteros‐Cánovas Juan A. , Díez‐Herrero Andres , Martínez‐Callejo Begoña
Published: July 2011

During recent archaeological work carried out in the 16th‐century Segovia Mint, Spain, a wooden deck of Pinus sylvestris was revealed covering the hydraulic canals. Dendrochronological analyses allowed us to estimate the dates that trees were felled in order to effect repairs to canals damaged after extraordinary flood events. There are at least three age clusters: (1) 1677–1678; (2) 1690–1698–1700; and (3) 1713–1720–1721–1742. By comparing dendrochronological data with both documentary records of repair work and the inventory of historical floods, the dates of the main floods affecting the building between 1583 and 1771 can be identified. Our work is innovative in that it uses tree‐ring dating in historical buildings to reconstruct past flood events, which are then linked to documentary records. It has three main applications: validating documented flood dates, estimating their relative magnitude, and locating new non‐documented flood events or previously unknown historical repair work at this UNESCO World Heritage Site. © 2011 Wiley Periodicals, Inc.
A new Middle Ordovician (late Dapingian) hexactinellid sponge from Cumbria, UK
Authors: Botting Joseph P. , Muir Lucy A.
Published: July 2011

A new hexactinellid sponge, Heminectere rushtoni sp. nov., has been found in an old collection in Keswick Museum and Art Gallery, UK. The species belongs to a long‐ranging genus, but is one of very few Dapingian (Middle Ordovician) hexactinellids described to date, and presents additional information on the range of morphological features present in the group. Heminectere is included within the Protospongiidae, the definition of which is here restricted to vasiform or spheroidal, thin‐walled hexactinellids with a regular to subregular, quadruled architecture. The specimen, collected in 1884, also shows that there is potential for further discoveries of important sponge material in the Middle Ordovician of northwest England, and highlights the lack of Dapingian sponges as being most likely a result of collection deficiency rather than genuine rarity. Copyright © 2011 John Wiley & Sons, Ltd.
Employees' attitudes toward organizational change: A literature review
Authors: Choi Myungweon
Published: July 2011

Organizations are increasingly required to improve their ability to enhance employees' support or acceptance for change initiatives. In studies that have examined the conditions in which employees support organizational change, researchers have focused on various attitudinal constructs that represent employees' attitudes toward organizational change. The constructs, which frequently serve as key variables in these studies, include readiness for change, commitment to change, openness to change, and cynicism about organizational change. These constructs have distinct meanings and emphases and therefore they can provide us with different information regarding employees' evaluation of and concerns about particular change initiatives. In this literature review, the author discusses how the constructs are defined in the organizational change literature and synthesizes the antecedents of each construct. Based on the discussion, it is proposed that the constructs are susceptible to situational variables, and may change over time as individuals' experiences change; therefore, they are better conceptualized as states than as personality traits. ©2011 Wiley Periodicals, Inc.
Linking capacities of high‐quality relationships to team learning and performance in service organizations
Authors: Brueller Daphna , Carmeli Abraham
Published: July 2011

This study examines the impact of intrateam and external high‐quality relationships (HQRs) on learning processes and performance. Data collected from 178 teams in the service sector indicate that (a) intrateam HQRs (i.e., between team members and between team members and their manager) are related to psychological safety, which in turn facilitates learning processes; (b) external HQRs are associated directly with team learning; and (c) team learning is positively associated with enhanced team performance. The findings highlight the importance of both internal and external HQRs to facilitate learning and enhance performance in service organizations. © 2011 Wiley Periodicals, Inc.
Socialization of people with disabilities in the workplace
Authors: Kulkarni Mukta , Lengnick‐Hall Mark L.
Published: July 2011

Socialization has crucial outcomes for both the employee and the employer. Through an exploratory qualitative study conducted in India, we examined how people with disabilities (PWD) viewed various aspects of their socialization process. Specifically, we looked at the role of coworkers, supervisors, organizational practices, and employee proactive behaviors in influencing organizational integration. We found that integration was most influenced by coworkers and supervisors. Organizational practices and employee proactive behaviors were less important. Respondent gender and tenure also influenced certain findings. Specifically, PWD with less tenure sought and accepted more help from coworkers and supervisors. Further, more men with disabilities than women with disabilities indicated that they were proactive in terms of obtaining training to make themselves employable, and more men with disabilities indicated that having coworkers with a disability helped them during socialization. We discuss both theoretical and practical implications as well as future research directions based on our findings. © 2011 Wiley Periodicals, Inc.
Organizational achievement values, high‐involvement work practices, and business unit performance
Authors: O'Neill Olivia A. , Feldman Daniel C. , Vandenberg Robert J. , DeJoy David M. , Wilson Mark G.
Published: July 2011

This study examines the relationships among organizational achievement values, high‐involvement work practices (HIWP), and business unit performance. Specifically, we examine whether HIWP mediate or moderate the effect of achievement values on retail store performance. Using data collected at three points in time from more than 1,000 employees, we found support for the mediation model. The article concludes with directions for future research and implications for management practice. © 2011 Wiley Periodicals, Inc.
Leadership change and shareholder value: How markets react to the appointments of women
Authors: Cook Alison , Glass Christy
Published: July 2011

This study examines whether the appointment of women into senior leadership positions has a more positive effect on share price than the appointment of men into equivalent positions. Our dependent variable is the degree of change in share price following the announcement of men and women into senior leadership positions. Although market reactions to corporate events represent a complex process, we argue that changes in stock price represent a barometer for how investors assess the decision's potential effect on a corporation's short‐ and long‐term economic viability. We find a significant spike in stock price following the announcement of women into top leadership positions. The size and direction of change in stock price, however, is moderated by the gender composition of the industry. © 2011 Wiley Periodicals, Inc.
Effect of bed surface roughness on longitudinal dispersion in artificial open channels
Authors: Schulz Marcus , Priegnitz Jan , Klasmeier Jörg , Heller Stefan , Meinecke Stefan , Feibicke Michael
Published: July 2011

In several empirical and modelling studies on river hydraulics, dispersion was negatively correlated to surface roughness. In this study, it was aimed to investigate the influence of surface roughness on longitudinal dispersion under controlled conditions. In artificial flow channels with a length of 104 m, tracer experiments with variations in channel bed material were performed. By use of measured tracer breakthrough curves, average flow velocity, mean longitudinal dispersion, and mean longitudinal dispersivity were calculated. Longitudinal dispersion coefficients ranged from 0·018 m2 s−1 in channels with smooth bed surface up to 0·209 m2 s−1 in channels with coarse gravel as bed material. Longitudinal dispersion was linearly related to mean flow velocity. Accordingly, longitudinal dispersivities ranged between 0·152 ± 0·017 m in channels with smooth bed surface and 0·584 ± 0·015 m in identical channels with a coarse gravel substrate. Grain size and surface roughness of the channel bed were found to correlate positively to longitudinal dispersion. This finding contradicts several existing relations between surface roughness and dispersion. Future studies should include further variation in surface roughness to derive a better‐founded empirical equation forecasting longitudinal dispersion from surface roughness. Copyright © 2011 John Wiley & Sons, Ltd.
Influence diagrams as decision-making tools for pesticide risk management
Authors: Carriger John F , Newman Michael C
Published: July 2011

The pesticide policy arena is filled with discussion of probabilistic approaches to assess ecological risk, however, similar discussions about implementing formal probabilistic methods in pesticide risk decision making are less common. An influence diagram approach is proposed for ecological risk-based decisions about pesticide usage. Aside from technical data, pesticide risk management relies on diverse sources, such as stakeholder opinions, to make decisions about what, how, where, and when to spray. Bayesian influence diagrams allow multiple lines of evidence, including process related information from existing data and expert judgment, in 1 inclusive decision model. In ecological risk assessments, data informally incorporated for pesticide usage decisions, such as field and laboratory effect studies along with chemical monitoring and modeling data, can be formally incorporated and expressed in linked causal diagrams. A case study is presented from the perspective of an environmental manager wishing to efficiently control pests while minimizing risk to local aquatic receptors. Exposure modeling results and toxicity studies were incorporated, and an ecological risk assessment was carried out but combined with hypothetical information on spraying efficacy and valuation of outcomes that would be necessary for making risk management decisions. The variables and their links in the influence diagram are ones that are important to a manager and can be manipulated to optimally control pests while protecting nontarget resources. Integr Environ Assess Manag 2012; 8: 339–350. © 2011 SETAC
Environmental engineering of navigation infrastructure: A survey of existing practices, challenges, and potential opportunities
Authors: Fredette Thomas J , Foran Christy M , Brasfield Sandra M , Suedel Burton C
Published: July 2011

Navigation infrastructure such as channels, jetties, river training structures, and lock-and-dam facilities are primary components of a safe and efficient water transportation system. Planning for such infrastructure has until recently involved efforts to minimize impacts on the environment through a standardized environmental assessment process. More recently, consistent with environmental sustainability concepts, planners have begun to consider how such projects can also be constructed with environmental enhancements. This study examined the existing institutional conditions within the US Army Corps of Engineers and cooperating federal agencies relative to incorporating environmental enhancements into navigation infrastructure projects. The study sought to (1) investigate institutional attitudes towards the environmental enhancement of navigation infrastructure (EENI) concept, (2) identify potential impediments to implementation and solutions to such impediments, (3) identify existing navigation projects designed with the express intent of enhancing environmental benefit in addition to the primary project purpose, (4) identify innovative ideas for increasing environmental benefits for navigation projects, (5) identify needs for additional technical information or research, and (6) identify laws, regulations, and policies that both support and hinder such design features. The principal investigation tool was an Internet-based survey with 53 questions. The survey captured a wide range of perspectives on the EENI concept including ideas, concerns, research needs, and relevant laws and policies. Study recommendations included further promotion of the concept of EENI to planners and designers, documentation of existing projects, initiation of pilot studies on some of the innovative ideas provided through the survey, and development of national goals and interagency agreements to facilitate implementation. Integr Environ Assess Manag 2012;8:1–1. © 2011 SETAC
Myosin heavy chain is not selectively decreased in murine cancer cachexia
Authors: Cosper Pippa F. , Leinwand Leslie A.
Published: July 2011

Cachexia is a severe muscle‐wasting syndrome associated with several chronic diseases such as cancer and AIDS. Muscle mass loss significantly decreases prognosis and survival. The mechanisms of muscle atrophy and the specific proteins targeted for degradation have been intensely studied and are potential therapeutic targets. Published reports that myosin heavy chain (MyHC), the most abundant protein by mass in skeletal muscle, is selectively targeted for degradation in cancer cachexia remain controversial. Here we show that the results of previous studies showing a selective decrease in MyHC are likely an artifact resulting from muscle lysis methods which do not solubilize myosin out of myofibrils. We show that MyHC decreases in parallel with other myofibrillar proteins in cachectic skeletal muscle, which has mechanistic and therapeutic implications. These findings should lead to mechanistic insight into the stoichiometry of sarcomeric disassembly and degradation during cancer cachexia.