bluuebunny/crossref_metadata_2025 huggingface dataset:
High levels of cryptic species diversity uncovered in Amazonian frogs
Authors: Funk W. Chris , Caminer Marcel , Ron Santiago R.
Published: December 2011

One of the greatest challenges for biodiversity conservation is the poor understanding of species diversity. Molecular methods have dramatically improved our ability to uncover cryptic species, but the magnitude of cryptic diversity remains unknown, particularly in diverse tropical regions such as the Amazon Basin. Uncovering cryptic diversity in amphibians is particularly pressing because amphibians are going extinct globally at an alarming rate. Here, we use an integrative analysis of two independent Amazonian frog clades,Engystomopstoadlets andHypsiboastreefrogs, to test whether species richness is underestimated and, if so, by how much. We sampled intensively in six countries with a focus in Ecuador (Engystomops: 252 individuals from 36 localities;Hypsiboas: 208 individuals from 65 localities) and combined mitochondrial DNA, nuclear DNA, morphological, and bioacoustic data to detect cryptic species. We found that in both clades, species richness was severely underestimated, with more undescribed species than described species. InEngystomops, the two currently recognized species are actually five to seven species (a 150–250% increase in species richness); inHypsiboas, two recognized species represent six to nine species (a 200–350% increase). Our results suggest that Amazonian frog biodiversity is much more severely underestimated than previously thought.
Polyamines Attenuate Ethylene-Mediated Defense Responses to Abrogate Resistance to Botrytis cinerea in Tomato
Authors: Nambeesan Savithri , AbuQamar Synan , Laluk Kristin , Mattoo Autar K. , Mickelbart Michael V. , Ferruzzi Mario G. , Mengiste Tesfaye , Handa Avtar K.
Published: December 2011

Transgenic tomato (Solanum lycopersicum) lines overexpressing yeast spermidine synthase (ySpdSyn), an enzyme involved in polyamine (PA) biosynthesis, were developed. These transgenic lines accumulate higher levels of spermidine (Spd) than the wild-type plants and were examined for responses to the fungal necrotrophs Botrytis cinerea and Alternaria solani, bacterial pathogen Pseudomonas syringae pv tomato DC3000, and larvae of the chewing insect tobacco hornworm (Manduca sexta). The Spd-accumulating transgenic tomato lines were more susceptible to B. cinerea than the wild-type plants; however, responses to A. solani, P. syringae, or M. sexta were similar to the wild-type plants. Exogenous application of ethylene precursors, S-adenosyl-Met and 1-aminocyclopropane-1-carboxylic acid, or PA biosynthesis inhibitors reversed the response of the transgenic plants to B. cinerea. The increased susceptibility of the ySpdSyn transgenic tomato to B. cinerea was associated with down-regulation of gene transcripts involved in ethylene biosynthesis and signaling. These data suggest that PA-mediated susceptibility to B. cinerea is linked to interference with the functions of ethylene in plant defense.
Germinal center B‐cell‐like diffuse large B‐cell lymphoma of the duodenum is associated with t(14;18) translocation
Authors: Tamura Maiko , Takata Katsuyoshi , Sato Yasuharu , Nakamura Naoya , Kikuti Yara Yukie , Ichimura Koichi , Tanaka Takehiro , Tari Akira , Maeda Yoshinobu , Tanimoto Mitsune , Okada Hiroyuki , Yoshino Tadashi
Published: December 2011

Diffuse large B‐cell lymphoma (DLBCL) rarely involves the duodenum, and its clinicopathological characteristics have not been well elucidated. We performed clinicopathological examinations and identified 15 patients with duodenal DLBCL using 18 gastric or colonic DLBCL as a control. Eleven of the 15 patients (73%) were subclassified by immunohistochemical analysis according to the Choi algorithm as germinal center B‐cell‐like (GCB) type, whereas the 18 control gastric and colonic DLBCL were predominantly subclassified as activated B‐cell‐like (ABC) type. The classifications according to organ involvement were statistically significant (P= 0.011 and P= 0.035). Macroscopically, the GCB lesions were varied, while all ABC lesions were ulcerative. Fluorescence in situ hybridization analysis revealed a higher frequency of t(14;18) translocation in patients with duodenal DLBCL (3 of 13) as compared with non‐duodenal gastrointestinal tract DLBCL (0 of 18), however, the difference was not significant (P = 0.064). Furthermore, the three patients with t(14;18) translocations were classified as GCB. In addition, overall survival of patients was statistically different between those with and without t(14;18) translocation (P= 0.040). In conclusion, duodenal DLBCL predominantly exhibits GCB‐type tumors and the frequency of t(14;18) translocation appears to be higher in duodenal GCB‐type DLBCL compared to non‐duodenal tumors.
Too good to be true: pitfalls of using mean Ellenberg indicator values in vegetation analyses
Authors: Zelený David , Schaffers André P.
Published: December 2011

Question

Mean Ellenberg indicator values (EIVs) inherit information about compositional similarity, because during their calculation species abundances (or presence–absences) are used as weights. Can this similarity issue actually be demonstrated, does it bias results of vegetation analyses correlating mean EIVs with other aspects of species composition and how often are biased studies published?

Methods

In order to separate information on compositional similarity possibly present in mean EIVs, a new variable was introduced, calculated as a weighted average of randomized species EIVs. The performance of these mean randomized EIVs was compared with that of the mean real EIVs on the one hand and random values (randomized mean EIVs) on the other. To demonstrate the similarity issue, differences between samples were correlated with dissimilarity matrices based on various indices. Next, the three mean EIV variables were tested in canonical correspondence analysis (CCA), detrended correspondence analysis (DCA), analysis of variance (ANOVA) between vegetation clusters, and in regression on species richness. Subsequently, a modified permutation test of significance was proposed, taking the similarity issue into account. In addition, an inventory was made of studies published in the Journal of Vegetation Science and Applied Vegetation Science between 2000 and 2010 likely reporting biased results due to the similarity issue.

Results

Using mean randomized EIVs, it is shown that compositional similarity is inherited into mean EIVs and most resembles the inter‐sample distances in correspondence analysis, which itself is based on iterative weighted averaging. The use of mean EIVs produced biased results in all four analysis types examined: unrealistic (too high) explained variances in CCA, too many significant correlations with ordination axes in DCA, too many significant differences between cluster analysis groups and too high coefficients of determination in regressions on species richness. Modified permutation tests provided ecologically better interpretable results. From 95 studies using Ellenberg indicator values, 36 reported potentially biased results.

Conclusions

No statistical inferences should be made in analyses relating mean EIVs with other variables derived from the species composition as this can produce highly biased results, leading to misinterpretation. Alternatively, a modified permutation test using mean randomized EIVs can sometimes be used.
Research Progress on Improving the Photovoltaic Performance of Polymer Solar Cells
Authors: Wang Yanmin
Published: December 2011

Although polymer materials possess the advantages such as low cost and easy fabrication of flexible and large-scale film for the application in photovoltaic devices, the performance of polymer-based solar cells, especially energy conversion efficiency is inferior to their inorganic counterpart due to the shorter charge diffusion length caused by the comparatively lower electric field between the electrodes. This paper reviewed the strategies to improve their photovoltaic properties mainly concentrated on modifying the polymer materials and ameliorating the device configuration. First, polythiophene (PT), poly(phenylene vinylene) (PPV), polyfullerene, and other novel polymer materials were introduced and the effective ways to modify their derivatives with more advantages were described in detail, for instance, copolymerization, incorporating additives and dyes, etc. Furthermore, the content of ameliorating the device configuration encompassed on inverted architecture, tandem structure, the introduction of buffer layers, thermal annealing, and the integration of optimized conditions. Finally, the effects of the improvement methods were concisely summarized, and the perspectives of the future research were put forth.
John S. Bell’s concept of local causality
Authors: Norsen Travis
Published: December 2011

John Stewart Bell’s famous theorem is widely regarded as one of the most important developments in the foundations of physics. Yet even as we approach the 50th anniversary of Bell’s discovery, its meaning and implications remain controversial. Many workers assert that Bell’s theorem refutes the possibility suggested by Einstein, Podolsky, and Rosen (EPR) of supplementing ordinary quantum theory with “hidden” variables that might restore determinism and/or some notion of an observer-independent reality. But Bell himself interpreted the theorem very differently—as establishing an “essential conflict” between the well-tested empirical predictions of quantum theory and relativistic local causality. Our goal is to make Bell’s own views more widely known and to explain Bell’s little-known formulation of the concept of relativistic local causality on which his theorem rests. We also show precisely how Bell’s formulation of local causality can be used to derive an empirically testable Bell-type inequality and to recapitulate the EPR argument.
A Comparative Study of Carbon-Supported Pt-Mo and Pt-Ru Catalysts for the Anodic Oxidation of Methanol
Authors: Ugalde Reyes Orlando , Roquero Pedro , Hernández Maya Roberto , Ocampo Flores Ana Lilia , Sosa Hernández Eliceo
Published: December 2011

Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
Use of Li(1-x) Mn2O4 Phase as Li-Ion Battery Cathode
Authors: Romero-Núñez Araceli , Ibarra-Palos Alejandro
Published: December 2011

A set of Li1-xMn2O4 type compounds was synthesized by chemical delithiation of LiMn2O4 spinel. Different concentrations of HCl aqueous solution were used to perform the lithium extraction process. Eight Li1-xMn2O4 phases, in which x can take values between 1 and 0, were obtained and characterized by RXD, SEM, IBA, Rietveld and Bond Valence analyses. Also, an electrochemical study was performed; obtained phases were assembled as a positive electrode in a Li-ion rechargeable system. Cyclic voltammetry of seventy five charge-discharge cycles shows better behavior of some of the extracted phases. However no relation between electrochemical behavior and extraction level was found.
Effect of SiCp as Reinforcement on the Corrosion Behavior of Cast Al-Mg Matrix
Authors: Hernández M. A. , Valdez Socorro
Published: December 2011

Metal matrix composite (MMC) are engineered materials manufactured by the action of incorporated reinforcement materials into metal matrix. As a result, stiff and hardened reinforcing phase in metallic matrix is obtained. The matrix includes a wider range of non-ferrous structures; meanwhile reinforcing phases comprise hardened nonmetallic particulates. The purpose of this paper is to investigate microstructural and electrochemical behavior of Al-Mg matrix reinforced with SiC particles (SiCp). The aluminum metal matrix composite was manufactured by the foundry vortex method. In the vortex process, SiC particles mixed into steel tubes at 1500 rpm were added to molten Al-Mg as-cast alloy. The metal-matrix composite (MMC) was characterized with the purpose of studying chemical interactions of SiC particles with the metal-matrix and its respective effect in electrochemical behavior. Results show that anodic dissolution in the cast Al-Mg matrix was accelerated by the formation of a non-stable oxide layer exhibiting partial protection with small resistance to polarization conditions, while the corrosion phenomena in Al-MMC was inhibited by the addition of silicon carbide particles
Electrochemical Noise Analysis for Nylon/Titanium Hybrid Materials
Authors: Menchaca-Campos Carmina , Hernandez-del Fabbro Sara , Sarmiento-Bustos Estela E. , Cruz-Silva Rodolfo , García-Sánchez Miguel Angel , Bahena Daniel , Uruchurtu Chavarín Jorge
Published: December 2011

Development of hybrid materials is a necessity. Polymeric materials are widely used in industry because their superior properties. In this work, synthesis, characterization and electrochemical noise evaluation of hybrid materials casted from nylon 6-6 and titanium are involved. Synthesis was carried out with 30, 40 and 50% wt of titanium functionalized with APTES. The materials obtained were characterized through scanning electron microscopy (SEM), thermal analysis (TA), infrared spectroscopy (IR) and electrochemical noise technique in Hank solution to simulate the internal fluids of the human body, in terms of biomaterial application, amongst others. SEM shows a homogenous material. Concentration of titanium was verified with TA. IR spectra show differences between Ny-Ti at different concentrations. Hybrid material made with 50%wt titanium present the lower resistance and the 30% wt the highest, as electrochemical noise resistance confirms. All samples show high resistivity in atmospheric conditions, while in Hank solution electrochemical characteristics were observed
Electrochemical Evaluation of Opuntia Ficus and Tobacco Waste Extracts as Corrosion Inhibitors on Mild Steel in NaCl and HCl Solutions
Authors: Ramírez Reyes José L. , Mancera Guillermina G. , Gómez Francisco Javier R. , Gallardo Castán Ernesto , Rendón Reyes C.
Published: December 2011

The corrosion inhibiting properties for the opuntia ficus (nopal mexican) and residues of cigars tobacco as extracts are evaluated here as an alternative to the use of inorganic inhibitors. For the evaluation of the extracts were made use of electrochemical methods as linear polarization resistance (LPR)and electrochemical impedance spectroscopy (EIS, which are very reliable techniques for the study of the corrosion mechanisms occurring at the interface between metallic sustrate and the films formed by the action of the inhibitors. The EIS results were analyzed applying the Boukamp program and using a model of equivalent circuit that combine the film formed time constant with the charge transfer and diffusion response for both corrosion reactions. The main results determined that the best performance was obtained using extracts 1% by weight and aggressive agents also at the lower chloride solutions concentration here used at 1% HCl and 3% NaCl.
Evaluation of PbSn Alloys Corrosion Inhibition Using Tin and PbO2 Coatings
Authors: García-Esparza Salvador , Flores Lira Ricardo , Videa Marcelo V.
Published: December 2011

One of the main failure modes in Lead-Acid Batteries (LAB) is corrosion at the positive plate. This problem has increased significantly the number of warranty claims, becoming a significant loss for this industry. Attempts to prevent corrosion in LABs include the application coatings of metallic oxides in the positive plate. In this work the use of tin and PbO2 as anti-corrosion coatings is explored. The coatings were prepared by electroless deposition and electrodeposition using current pulses. Corrosion rate of grid samples was determined, with and without coating, from Tafel plots. It was found that electrodeposited tin coated grids had the highest corrosion inhibition. On the other hand, electroless tin deposits had the lowest corrosion inhibition activity showing a higher corrosion rate than the uncoated alloy.
Adenine and Guanine Derivative Bases of Purines and Their Corresponding Nucleosides as Corrosion Inhibitors in 1M Hydrochloric Acid
Authors: Cruz-Gonzalez D.Y. , Negrón-Silva Guillermo , Angeles-Beltrán Deyanira , Palomar-Pardavé Manuel , Romero-Romo Mario , Herrera-Hernández H.
Published: December 2011

This work reports on the studies carried out with adenine, guanine and their corresponding nucleosides as adequate corrosion inhibitor candidates for steel API 5L X52 in 1M HCl. Electrochemical impedance spectroscopy served to perform corrosion testing varying the compounds' concentrations from 5 to 200 volume ppm. A relation was obtained between inhibiting compound candidate concentration and the overall corrosion inhibition efficiency, where 25 ppm appeared as the optimum concentration for all electrochemical systems tested.
Evaluating the Protection Effect of Galvanized Coatings on Reinforcing Bars for Concrete
Authors: Torres Acosta Andres A. , Alemán Andrade Vladimir J. , Herrera Núñez Maria J.
Published: December 2011

Reinforced concrete structures exposed to severe environments are susceptible to corrosion, decreasing substantially its service life performance. To avoid such deteriorations, the use of protective coatings to the reinforcing steel bar, also called rebar (i.e. Galvanizing), is increasing in the last two decades. The galvanizing process is the formation of a metallic layers (zinc, Zn, and iron-zinc, Fe-Zn, alloys) on the steel surface. This metal not only works as a physical barrier, but also acts as a galvanic anode protecting to the steel, from corrosion. This galvanic mechanism of Zn on alkaline media has some drawback as for how long it will last if Zn also corrodes in alkaline media, before hazardous chemicals (i.e. chlorides and CO2) reach the embedded steel. In this work, some defects were created on galvanized rebars in order to evaluate the sacrificial effect of Zn and the effect of chloride addition.
Self-Organization Phenomena During Electrodeposition of Ag-In Alloys
Authors: López Sauri Daniel A. , Dobrovolska Tsvetina , Veleva Lucien , Estrella-Gutiérrez Manuel A. , Krastev Ivan
Published: December 2011

In situ potentiostatic and galvanostatic investigations on the pattern formation depending on the electrolysis conditions during electrodeposition of silver-indium alloys were done. Cyclic voltammetry of silver, indium and silver-indium alloy were performed in parallel with electrochemical measurements. Spacio-temporal structures were observed during electrodeposition of silver-indium alloys en the following sequence: appearance of spots, targets and spirals 5-10 minutes after beginning of the electrolysis. The investigations were possible because of the colorless electrolyte and the large scale of the observed structures.
Effect of Some Additives on the Silver Electrodeposition Process
Authors: Mendez-Aguilar Marco T. , Garfias-Ayala Francisco J. , Garfias-Vazquez Francisco J.
Published: December 2011

Silver production is an important economical activity in Mexico, and therefore it is essential to do research to optimize its process. One of the process drawbacks is low current efficiency because of dendritic crystal growth. The present work analyzes the effect of adding surfactants to the AgNO3 electrolyte to increase current efficiency (CE) and consequently to lower energy consumption (EC) and to better physical appearance (AF) by means of observing crystal structure by X-ray diffraction and scanning electron microscope. The surfactants used were: tetra methyl ammonium chloride (TMAC), tetra buthyl ammonium chloride (TBAC), sodium dodecyl sulphate (SDS), decyl amine (DA), and decyl alcohol (AD). The surfactants (TBAC) and (AD) improved positively (AF) and (CE).
Electrosynthesis of β-Ni(OH)2 and Electrochemical Response of β-Ni(OH)2/CB-PVC Composite Electrode
Authors: González-Perea Mario , Dávila-Jiménez Martín M. , García Aditaín , Elizalde-González María de la P. , Ruiz Patricia
Published: December 2011

Nickel hydroxide powder was synthesized by electrochemical oxidation of a nickel electrode under potentiostatic conditions in NaF 0.1 M. The structure and morphology of the nickel hydroxide was characterized using XRD and ATR. The study confirmed the formation of β-nickel hydroxyde. The electrochemical performance of a β-Ni(OH)2/CB-PVC electrode was investigated by cyclic voltammetry and the galvanostatic charge-discharge technique. The electrocatalytic efficiency of β-Ni(OH)2 was studied for the oxygen evolution and ethanol electrooxidation reactions in 0.1 M KOH.
Cr(VI) Reduction in Aqueous Solution by Electrochemical Process Using Boron Doped Diamond Electrode (BDD)
Authors: Velazquez-Peña Sarai , Linares-Hernández Ivonne , Barrera-Díaz Carlos E. , Martínez-Miranda Verónica , Lugo-Lugo Violeta , Almazán-Sánchez Perla T.
Published: December 2011

In this study we present the Cr(VI) reduction in synthetic wastewater using an electrochemical cell using boron doped diamond electrodes (BDD). The best conditions were found when Fe-DDB configuration was used. It is observed that when more current is applied into the electrochemical cell faster reduction rates are achieved. To confirm the experimental data, cyclic voltammetry was used and it was found that the cathodic Cr(VI) reduction is taking place.
Potential Measurements Used to Study the Bentonite-Pollutant and Kaolin-Pollutant Interphase
Authors: Sumbarda Ramos Emigdia G. , Oropeza Guzmán Mercedes T. , Salgado Rodríguez Rodolfo , Teutli-León M.M.M.
Published: December 2011

To support the application of an electrokinetic treatment to clay soils polluted with metals, a study of the interphase soil-pollutant-soil solution was carried out based on Zeta Potential (ζ) measurements. The physicochemical and transport phenomena that occur during electrokinetic treatment due to the soil-pollutant interaction at different electrolytes can be deduced from the ζ values. The experimental work begins with the physicochemical characterization of two clays: Bentonite (B) and Kaolin (K). Both samples were converted to homoionic form in order to observe the superficial adsorption of cations. 1M solutions of (NH4)2SO4, NH4Cl and CuSO4, CuCl2 were chosen for this purpose. Copper concentration, cation exchange capacity (CEC) and ζ were analyzed in the homoionic samples to study the soil-pollutant interaction. Results show that the adsorption/desorption process can be studied by the ζ values; these values reflect the chemical changes at the soil-pollutant-soil solution interphase.
Amperometric Titration of Fructan Oligosaccharides of Agave Tequilana Webber, Blue Variety, in a Rotating Disk Electrode
Authors: Herrera-Gonzalez Azucena , Arrizon Javier , Bárcena-Soto Maximiliano , Soltero-Martinez Armando , Mateos-Diaz Juan C. , Casillas Norberto
Published: December 2011

This paper deals with a simple, rapid and sensitive method for quantifying oligosaccharides of fructans of Agave Tequilana Webber a Blue Variety. The method is based on the oxidation of the carbonyl group of the oligosaccharide in its linear open-ring with ferricyanide ions in a RDE (rotating disk electrode). The amperometric titration is carried out at different temperatures, e.g., 60, 65, 70, 75, 80 and 85 °C as a strategy to control the amount of oligosaccharides with the open-ring as a function of their molecular size. The proposed method allows us to determine concentrations of oligosaccharides as low as 0.71 mM. A calibration curve between the limiting current of the Fe(CN)63-/Fe(CN)64- pair and the concentration of the oligosaccharides taking into account the effect of temperature in the physical properties of the system, such as, density, diffusion coefficients and viscosity is also presented.
Supramolecular Systems Construction for the Selective Quantitative Determination of Dopamine in the Presence of Ascorbic Acid
Authors: Corona Avendaño Silvia , Alarcón-Ángeles Georgina , Romero-Romo Mario , Merkoçi Arben , Rojas-Hernández Alberto , Ramírez-Silva Ma. Teresa , Palomar-Pardavé Manuel
Published: December 2011

The results presented here concern the quantitative determination of dopamine in the presence of ascorbic acid, by means of differential pulse voltammetry using a b-Cyclodextrin modified carbon paste electrode, with its polymer poly-b-Cyclodextrin (polyb-CD), with multi-walled carbon nanotubes (MWCNT), and with the combination of MWCNT with polyb-CD. Each of these electrodes allowed the analytes of interests peaks' separation, i.e. dopamine and ascorbic acid. However, with the MWCNTb-CD/polyb-CD, the results obtained were not as good as with the electrodes modified with polyb-CD and with MWCNT / b-CD of which the detection and quantification limits were 4.10 and 5.71 micromolar, respectively. Also, the determination of dopamine in a commercial pharmaceutical was performed with the best two electrodes giving good results.
Electrochemical Oxidation of Synthetic Analogous of Capsaicin in Hartmann Solution
Authors: Calvillo Maria Patricia , Camacho Gisel Andrea , Córdova Ivan , Oropeza Mercedes Teresita
Published: December 2011

This work describes the oxidation potential of five synthetic analogous of capsaicin in Hartmann solution by differential pulse voltammetry (DPV) and square wave voltammetry (OSWV), the undec-10-enoate (4-hydroxy-3-methoxyphenyl) methyl showed the low oxidation potential (+460 and +496 mV by DPV and OSWV, respectively), these results qualify the compound as a good antioxidant agent.
Electrochemical Study of the Formation of Surface Inclusion Complex of Ascorbic Acid with Immovilized β-Ciclodextrin and Carbon Nanotubes over a Carbon Paste Electrode
Authors: Palomar-Pardavé Manuel , Alarcón-Ángeles Georgina , Corona Avendaño Silvia , Romero-Romo Mario , Merkoçi Arben , Rojas-Hernández Alberto , Ramírez-Silva Ma. Teresa
Published: December 2011

This work dealt with the formation of supramolecular complexes that proved to be basic for the design of electrochemical sensors to undertake quantitative determination of an analyte of interest, like ascorbic acid, AA. Also, the results from this study demonstrated that the AA formed supramolecular complexes with b-cyclodextrine, b-CD, in solution and with its polymeric species: poly-b-CD, over the surface of a carbon paste working electrode that was modified with multiwalled-carbon nanotubes, MWCNT. The said three modifying agents permitted to discern the electrochemical response of the AA that interacted on the electrode surface, thus giving rise to a measurable response through an adsorption processes, particularly for the electrode modified with the poly-b-CD. Do not indent the first line of the abstract
Electrocatalytic Process on Carbon Paste Electrode Modified with a Fe-5-Aphen Metalcomplex
Authors: Lozano Camargo Maria Luisa , Galicia Laura
Published: December 2011

The electrocatalytical behaviour of carbon paste electrode (CPE) modified with poly Fe(III)-5-Aphen were studied for the oxygen electroreduction reaction (ORR) in acid medium. The ORR on CPE modified electrode follows a mechanism via 4 electrons. Electrokinetic parameters obtained in this work are comparable with those reported for other metallic porphyrins and phthalocyanines used as electrocatalyst. The stability of the CPE modified electrode in the reduction of oxygen is maintained at least for 30 days after been prepared. Only after this time there is a slight modification of the electrode surface with an increase of 50 mV in the cathodic overpotencial for RRO.
Simulation and Modelling of Atratone Herbicide Extraction at the Immiscible Liquid System Using an Electrochemical Reactor
Authors: Santos-Mendoza Ilda Olivia , López-Arjona Hector , Velázquez-Manzanares Miguel
Published: December 2011

In the present work a modeling and mathematical simulation of the atratone herbicide extraction at the immiscible electrolyte solutions system was studied. As subject of study, it was considered a biphasic electrochemical reactor (water/organic solvent) with constant concentration of atratone in the water input flow during the extraction process. Using the experimental data obtained by cyclic voltammetry at the interface of two immiscible electrolyte solutions, such as transfer formal potential (Δ a o' φ o i) and the coefficient diffusion, this latter parameter was evaluated for the herbicide in both phases. Then a mathematical model was developed to describe the concentration profiles for this compound near the interface (aqueous and organic) and the total transfer across the interface. The suggested model is able to describe the transport behaviour of the herbicide across the interface and the optimums operation parameters were fixed in the model system allowing the extraction of the compound from water to organic phase.
Effect of Kinetics and Mass Transport in an Electrochemical Reactor for the Removal of Copper in Tequila
Authors: Rodíguez Alicia , Casillas Norberto , Sainz Abraham , Gómez-Salazar Sergio , Trujillo-Orozco Araceli , Prado-Ramírez Rogelio , Bárcena-Soto Maximiliano
Published: December 2011

The construction and application of a monopolar, packed bed, parallel plate electrochemical flow reactor to removal of Cu+2 ions from "ordinary" (i.e., product of the first distillation of tequila) is presented. The reactor is constructed by nylomaq frameworks to accommodate copper hanks cathodes, separated from graphite anodes by means of polypropylene (Celgard®) membranes. Results of the copper concentration profile in ordinary solutions and pH variation along the reactor are reported. Copper concentration continuously decreases along the reactor reaching a removal efficiency ranging from 82 to 85% for all the inlet concentrations examined. The experimental copper concentration profile fits an exponential decay along the axial reactor coordinate, in agreement with theory for porous flow reactors. An equation deduced from the material balance for a packed bed electrode (i.e., copper hanks), that takes into account a kinetic rate constant and mass transfer coefficient to predict the concentration vs. position along the reactor is also presented.
Electrochemical Treatment of Indigo Carmine Solutions via Active Chlorine in a FM01-LC Reactor Using DSA (Ti/IrO2/SnO2/Sb2O5) Electrodes
Authors: Rodríguez Francisca A. , Mateo María N. , Domínguez Rosario , Rivero Eligio P. , González Ignacio
Published: December 2011

The study of degradation of indigo carmine in NaCl solutions in a filter-press type FM01-LC reactor using dimensionally stable anodes, DSA (Ti/IrO2/SnO2/Sb2O5), is reported. In the first part, the microelectrolysis study of the DSA electrodes was carried out and subsequently the study of indigo carmine degradation in the FM01-LC reactor at different current densities (50 - 200 A m-2) and Reynolds numbers, Re (93-557), was performed. A complete mineralization of indigo carmine was attained in all experiments except those at low current density (50 A m-2). The participation of chloride and indigo carmine in electrochemical and degradation reactions is discussed in the work on the basis of the experimental data. The results show that the degradation rate increases as function of the Re at high current density (200 A m-2) but becomes independent of the Re at low current density (50 A m-2)
A Demo-Genetic Analysis of a Small Reintroduced Carnivore Population: The Otter (Lutra lutra) in The Netherlands
Authors: Seignobosc Maelle , Hemerik Lia , Koelewijn Hans Peter
Published: December 2011

Assessing the viability of reintroduced animal populations is a complicated task. Reintroductions are usually carried out with a small number of individuals, thereby, limiting the possibilities for monitoring because of the possible negative effects of intensive monitoring on survival and reproduction. Moreover, reintroduction studies are part of a socioeconomic interplay of forces, thereby, also limiting monitoring possibilities. Also, knowledge of population demography and abundance can be incomplete or unattainable. Here, we illustrate how we combined traditional telemetry and novel non-invasive genetic methodology to construct a detailed life table of a small reintroduced otter population in The Netherlands. Combining an appropriate capture-mark-recapture framework with a matrix modelling approach provides, in general, useful insights for such populations. The data indicated that (i) male survival is lower than female survival, (ii) the reintroduced population is currently growing (estimatedλ=1.26: range [1.06, 1.42]) and seems viable, (iii) increasing adult survival is currently the critical stage at which efforts of field managers should concentrate, and (iv) the modelling framework allowed us to determine the boundary conditions for the vital rates under which the population would go extinct. The applied approach directs at measurements that help field managers to implement the right conservation strategy after reintroductions.
'Child-proofing' EU law and policy: interrogating the law-making processes behind European asylum and immigration provision
Authors: Drywood Eleanor
Published: December 2011

The EU is pursuing an increasingly explicit agenda in relation to young immigrants and asylum-seekers, leading the supra-national legislature to grapple with the question of how to ensure that children's rights are upheld through this body of law. The tool of mainstreaming, which ensures that a particular concern is promoted through its incorporation into the entire law-making process, has emerged as a key strategy in this regard. This article explores the use of mainstreaming within the specific context of children's rights and uses its implementation in the specific context of the European Union's (EU's) asylum and immigration laws as a case-study to assess both its successes and its shortcomings. Using similar mainstreaming activities in the gender equality arena by way of illustration, the analysis questions, in particular, the capacity of mainstreaming: to accommodate the heterogeneity of child migrants as a group; to ensure appropriate representation and coordination in relation to children's rights at institutional level; and to deliver an adequate knowledge base to underpin decision making in the legislative process in relation to young immigrants and asylumseekers. The discussion concludes by pointing to some of the current deficiencies of children's rights mainstreaming, and speculating on its capacity to successfully promote the needs of young people in EU laws and policies in the future.
The facsimile-edition of the Cologne manuscript of Justinian's Institutes and the Glossa Coloniensis
Authors: Feenstra Robert
Published: December 2011

In the commentary preceding the facsimile the main issues are date and provenance of the marginal glosses and of some additional pieces at the beginning and the end (Glossa Coloniensis). The editors mainly follow Charles M. Radding and Antonio Ciarelli, seeking the origins in a centre of Lombard law (Pavia) about 1125. This opinion was strongly criticized by the late André Gouron, preferring (Northern) French, English or German origins about 1170. The author suggests Cologne as the place of origin, arguing from the existence there of schools of canon and civil law about 1165–1185 (recalled recently by Peter Landau). He further criticizes the commentary on the development of law studies in Cologne in the 14th and 15th centuries.
Improved power by collapsing rare and common variants based on a data-adaptive forward selection strategy
Authors: Dai Yilin , Guo Ling , Dong Jianping , Jiang Renfang
Published: December 2011

Genome-wide association studies have been used successfully to detect associations between common genetic variants and complex diseases, but common single-nucleotide polymorphisms (SNPs) detected by these studies explain only 5–10% of disease heritability. Alternatively, the common disease/rare variants hypothesis suggests that complex diseases are often caused by multiple rare variants with moderate to high effects. Under this hypothesis, the analysis of the cumulative effect of rare variants may thus help us discover the missing genetic variations. Collapsing all rare variants across a functional region is currently a popular method to find rare variants that may have a causal effect on certain diseases. However, the power of tests based on collapsing methods is often impaired by misclassification of functional variants. We develop a data-adaptive forward selection procedure that selectively chooses only variants that improve the association signal between functional regions and the disease risk. We apply our strategy to the Genetic Analysis Workshop 17 unrelated individuals data with quantitative traits. The type I error rate and the power of different collapsing functions are evaluated. The substantially higher power of the proposed strategy was demonstrated. The new method provides a useful strategy for the association study of sequencing data by taking advantage of the selection of rare variants.
Collapsing-based and kernel-based single-gene analyses applied to Genetic Analysis Workshop 17 mini-exome data
Authors: Li Lun , Zheng Wei , Lee Joon Sang , Zhang Xianghua , Ferguson John , Yan Xiting , Zhao Hongyu
Published: December 2011

Recently there has been great interest in identifying rare variants associated with common diseases. We apply several collapsing-based and kernel-based single-gene association tests to Genetic Analysis Workshop 17 (GAW17) rare variant association data with unrelated individuals without knowledge of the simulation model. We also implement modified versions of these methods using additional information, such as minor allele frequency (MAF) and functional annotation. For each of four given traits provided in GAW17, we use the Bayesian mixed-effects model to estimate the phenotypic variance explained by the given environmental and genotypic data and to infer an individual-specific genetic effect to use directly in single-gene association tests. After obtaining information on the GAW17 simulation model, we compare the performance of all methods and examine the top genes identified by those methods. We find that collapsing-based methods with weights based on MAFs are sensitive to the “lower MAF, larger effect size” assumption, whereas kernel-based methods are more robust when this assumption is violated. In addition, many false-positive genes identified by multiple methods often contain variants with exactly the same genotype distribution as the causal variants used in the simulation model. When the sample size is much smaller than the number of rare variants, it is more likely that causal and noncausal variants will share the same or similar genotype distribution. This likely contributes to the low power and large number of false-positive results of all methods in detecting causal variants associated with disease in the GAW17 data set.
Family- and population-based designs identify different rare causal variants
Authors: Zhang Xue , He Hua , Ding Lili , Baye Tesfaye M , Kurowski Brad G , Martin Lisa J
Published: December 2011

Both family- and population-based samples are used to identify genetic variants associated with phenotypes. Each strategy has demonstrated advantages, but their ability to identify rare variants and genes containing rare variants is unclear. To compare these two study designs in the identification of rare causal variants, we applied various methods to the population- and family-based data simulated by the Genetic Analysis Workshop 17 with knowledge of the simulated model. Our results suggest that different variants can be identified by different study designs. Family-based and population-based study designs can be complementary in the identification of rare causal variants and should be considered in future studies.
Identification of genes and variants associated with quantitative traits using Bayesian factor screening
Authors: Pradhan Kith , Yoon Seungtai Chris , Wang Tao , Ye Kenny
Published: December 2011

We propose a factor-screening method based on a Bayesian model selection framework and apply it to Genetic Analysis Workshop 17 simulated data with unrelated individuals to identify genes and SNP variants associated with the quantitative trait Q1. A Metropolis-Hasting algorithm is implemented to generate a posterior distribution in a restricted model space and thus the marginal posterior distribution of each variant. Our framework provides flexibility to make inferences on either individual variants or genes. We obtained results for 10 simulated data sets. Our methods are able to identify FTP1 and KDR, two genes that are associated with Q1 in a majority of replicates.
Evaluating methods for combining rare variant data in pathway-based tests of genetic association
Authors: Petersen Ashley , Sitarik Alexandra , Luedtke Alexander , Powers Scott , Bekmetjev Airat , Tintle Nathan L
Published: December 2011

Analyzing sets of genes in genome-wide association studies is a relatively new approach that aims to capitalize on biological knowledge about the interactions of genes in biological pathways. This approach, called pathway analysis or gene set analysis, has not yet been applied to the analysis of rare variants. Applying pathway analysis to rare variants offers two competing approaches. In the first approach rare variant statistics are used to generate p-values for each gene (e.g., combined multivariate collapsing [CMC] or weighted-sum [WS]) and the gene-level p-values are combined using standard pathway analysis methods (e.g., gene set enrichment analysis or Fisher’s combined probability method). In the second approach, rare variant methods (e.g., CMC and WS) are applied directly to sets of single-nucleotide polymorphisms (SNPs) representing all SNPs within genes in a pathway. In this paper we use simulated phenotype and real next-generation sequencing data from Genetic Analysis Workshop 17 to analyze sets of rare variants using these two competing approaches. The initial results suggest substantial differences in the methods, with Fisher’s combined probability method and the direct application of the WS method yielding the best power. Evidence suggests that the WS method works well in most situations, although Fisher’s method was more likely to be optimal when the number of causal SNPs in the set was low but the risk of the causal SNPs was high.
Using linkage analysis of large pedigrees to guide association analyses
Authors: Choi Seung-Hoan , Liu Chunyu , Dupuis Josée , Logue Mark W , Jun Gyungah
Published: December 2011

To date, genome-wide association studies have yielded discoveries of common variants that partly explain familial aggregation of diseases and traits. Researchers are now turning their attention to less common variants because the price of sequencing has dropped drastically. However, because sequencing of the whole genome in large samples is costly, great care must be taken to prioritize which samples and which genomic regions are selected for sequencing. We are interested in identifying genomic regions for deep sequencing using large multiplex families collected as part of earlier linkage studies. We incorporate linkage analysis into our search for Q1-associated alleles. Overall, we found that power was low for both whole-exome and linkage-guided sequencing analysis. By restricting sequencing to regions with high LOD peaks, we found fewer associated single-nucleotide polymorphisms than by using whole-exome sequencing. However, incorporating linkage analysis enabled us to detect more than half of the associated susceptibility loci (52%) that would have been identified by whole-exome sequencing while examining only 2.5% of the exome. This result suggests that incorporating linkage results from large multiplex families might greatly increase the efficiency of sequencing to detect trait-associated alleles in complex disease.
TSH-induced gene expression involves regulation of self-renewal and differentiation-related genes in human bone marrow-derived mesenchymal stem cells
Authors: Bagriacik Emin Umit , Yaman Melek , Haznedar Rauf , Sucak Gulsan , Delibasi Tuncay
Published: December 2011

Bone marrow-derived mesenchymal stem cells are pluripotent cells that are capable of differentiating into a variety of cell types including neuronal cells, osteoblasts, chondrocytes, myocytes, and adipocytes. Despite recent advances in stem cell biology, neuroendocrine relations, particularly TSH interactions remain elusive. In this study, we investigated expression and biological consequence of TSH receptor (TSHR) interactions in mesenchymal stem cells of cultured human bone marrow. To the best of our knowledge, we demonstrated for the first time that human bone marrow-derived mesenchymal stem cells expressed a functional thyrotropin receptor that was capable of transducing signals through cAMP. We extended this study to explore possible pathways that could be associated directly or indirectly with the TSHR function in mesenchymal stem cells. Expression of 80 genes was studied by real-time PCR array profiles. Our investigation indicated involvements of interactions between TSH and its receptor in novel regulatory pathways, which could be the important mediators of self-renewal, maintenance, development, and differentiation in bone marrow-derived mesenchymal stem cells. TSH enhanced differentiation to the chondrogenic cell lineage; however, further work is required to determine whether osteoblastic differentiation is also promoted. Our results presented in this study have opened an era of regulatory events associated with novel neuroendocrine interactions of hypothalamic–pituitary axis in mesenchymal stem cell biology and differentiation.
Fatores associados à idade da primeira relação sexual em jovens: estudo de base populacional
Authors: Hugo Tairana Dias de Oliveira , Maier Vanessa Teixeira , Jansen Karen , Rodrigues Cristine Eliane Gomes , Cruzeiro Ana Laura Sicca , Ores Liliane da Costa , Pinheiro Ricardo Tavares , Silva Ricardo , Souza Luciano Dias de Mattos
Published: December 2011

A primeira relação sexual é considerada um evento importante na vida dos jovens e tem iniciado cada vez mais cedo. O objetivo do presente estudo foi descrever os fatores relacionados à idade precoce da primeira relação sexual, de jovens de 18 a 24 anos na cidade de Pelotas, Rio Grande do Sul, Brasil. Este é um estudo transversal de base populacional, em uma amostra representativa de 1.621 jovens que ocorreu entre agosto de 2007 e dezembro de 2008. Foram aplicados questionários sobre comportamentos de saúde que continham itens relativos à sexualidade. A regressão de Cox foi utilizada para aferir a associação com a idade precoce de início da vida sexual. Após a análise multivariada, as variáveis diretamente relacionadas com a iniciação sexual precoce foram: sexo masculino, baixo nível socioeconômico, baixa escolaridade, ter pais separados, morar com companheiro(a), não praticar uma religião, uso de tabaco e drogas, e o não uso da camisinha na última relação. Considerando o contexto social atual, evidencia-se a necessidade de uma adequada orientação sexual com aspecto preventivo.
Um arlequim jamais terminado: teatro, juventude e direito à cultura na periferia francesa
Authors: Sales Mione Apolinario
Published: December 2011

Este artigo consiste numa análise do filme A esquiva (França, 2003), de Abdellatif Kechiche, que narra como estudantes da periferia montam uma peça de teatro. O foco repousa sobre o modo de vida e a linguagem desses adolescentes, tendo como pano de fundo a problemática do direito à cultura. Para essa abordagem, foi feita uma pesquisa qualitativa, de natureza exploratória, na internet, a partir de arquivos disponíveis sobre o filme, desde 2003. A análise teve por base textos da crítica cinematográfica especializada e a reação dos espectadores em fóruns de discussão on-line, em sites franceses.