bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coordination Versatility of 5(3)‐(2‐Hydroxyphenyl)‐3(5)‐methylpyrazole: Synthesis, Crystal Structure and Properties of CoIII, NiII and CuII Complexes
Authors: Viciano‐Chumillas Marta , Tanase Stefania , Aromí Guillem , Smits Jan M. M. , de Gelder René , Solans Xavier , Bouwman Elisabeth , Reedijk Jan 
Published: May 2007

AbstractNew complexes with 5(3)‐(2‐hydroxyphenyl)‐3(5)‐methylpyrazole (H2phpz), [Co2(H2phpz)(Hphpz)2(phpz)2]·3CH3CN (1), [Ni(Hphpz)2] (2) and [Cu(Hphpz)2] (3), were synthesized and structurally characterized. The ligand coordinates in the form of 3‐(2‐hydroxyphenyl)‐5‐methylpyrazole in all cases, except for one ligand in the CoIII complex, where it coordinates in the 5‐(2‐hydroxyphenyl)‐3‐methylpyrazole mode. Crystallographic analysis revealed that 1 contains two chemically and crystallographically distinct cobalt(III) ions triply bridged by one phenoxide and two pyrazolate groups, giving rise to a [Co2(N‐N)2O] core with a Co···Co distance of 3.154 Å. Additionally, the H2phpz ligand shows four different coordination modes with the metal ions, demonstrating its versatility. The dinuclear unit of 1 is stabilized by strong intramolecular N–H···O hydrogen‐bonding interactions involving the phenol oxygen atom of the H2phpz ligand and the N–H functionality of the pyrazole ring. The crystal structure of the isomorphous complexes 2 and 3 reveals the presence of centrosymmetric mononuclear units with the MN2O2 [M = NiII (2), CuII (3)] chromophore displaying a slightly distorted square‐planar geometry. The mononuclear structures of 2 and 3 are further stabilized by intramolecular hydrogen bonds established between the acid N–H group as donor and the phenoxide group of the H2phpz ligand as acceptor. Spectroscopic studies, ESI‐MS and cyclic voltammetry were performed, supporting the crystallographic analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Determination of tocopherols and phytosterols in sunflower seeds by NIR spectrometry
Authors: Gotor Alicia Ayerdi , Farkas Eric , Berger Monique , Labalette Françoise , Centis Sylvie , Daydé Jean , Calmon Anne 
Published: May 2007

AbstractThe objective of this work was to develop a near‐infrared reflectance spectrometry (NIRS) calibration estimating the tocopherol and phytosterol contents in sunflower seeds. Approximately 1000 samples of grinded sunflower kernels were scanned by NIRS at 2‐nm intervals from 400 to 2500 nm. For each sample, standard measurements of tocopherol and phytosterol contents were performed. The total tocopherol content was obtained by high‐performance liquid chromatography coupled with a fluorescence detector, while the total phytosterol content was assessed by gas chromatography. For tocopherol, the calibration data set ranged from 175 to 1005 mg/kg oil (mean value around 510 ± 140 mg/kg oil), whereas for the phytosterol content, the calibration data set ranged from 180 to 470 mg/100 g oil (mean value of 320 ± 50 mg/100 g oil). The NIRS calibration showed a relatively good correlation (R2 = 0.64) between predicted by NIRS and real values for the total tocopherol content but a poor correlation for the total phytosterol content (R2 = 0.27). These results indicate that NIRS could be useful to classify samples with high and low tocopherol content. In contrast, the estimation of phytosterol contents by NIRS needs further investigation. Moreover, in this study, calibration was obtained by a modified partial least‐squares method; the use of other mathematical treatments can be suitable, particularly for total phytosterol content estimation.
Instrumental technique evolution for olive oil sensory analysis
Authors: Escuderos María Elena , Uceda Marino , Sánchez Sebastián , Jiménez Antonio 
Published: May 2007

AbstractAt present, two systems have been usually used to identify olive oil aroma: the official panel test, according to the European Union Regulation [1], and the gas chromatographic method and its improvements. However, both types of techniques have two principal disadvantages: They need a long time for analysis and cannot be applied on‐line. Recently, there has been increasing interest in the development of a new device, the so‐called “electronic nose”. The aim of this work is to perform both a review of these techniques used for olive oil sensory analysis and their advantages and disadvantages.
In‐process monitoring in industrial olive mill by means of FT‐NIR
Authors: Bendini Alessandra , Cerretani Lorenzo , Di Virgilio Fabio , Belloni Paolo , Lercker Giovanni , Toschi Tullia Gallina 
Published: May 2007

AbstractA total of 287 olive lots and 161 olive oil samples were analyzed for fat content, moisture and free acidity, using a Fourier transform near‐infrared (FT‐NIR) instrument located in an industrial mill. Samples having a wide range of both reference values and olive lot sizes (from <0.5 to >4 t) were collected at three industrial mill plants, located in the same Italian region, which utilize different technological equipment for virgin olive oil production. Olive paste spectra were acquired in diffuse reflectance, while oil samples were measured in transmission. Calibration models for oil content and moisture of olives as well as free acidity of virgin olive oils were developed using partial least squares (PLS) regression, first derivative and straight line subtraction. Results of calibration and validation of the PLS models selected were good. The PLS results indicate good similarity between data obtained from FT‐NIR and reference laboratory methods, allowing a rapid and less expensive screening analysis. Unfortunately, the correlation between the oil yield values recorded for all olive lots at the industrial mills and the oil content predicted by FT‐NIR was not satisfactory (R2 = 0.605).
Procedures for and Possible Mechanisms of Pd‐Catalyzed Allylations of Primary and Secondary Amines with Allylic Alcohols
Authors: Muzart Jacques 
Published: May 2007

AbstractThis review describes the different Pd‐catalyzed methods that afford allylic amines from intermolecular reactions between allylic alcohols and amines and, with personal comments, the mechanisms that have been proposed. Allylic amines are an important class of compounds, while a wide structural variety of allylic alcohols are commercially available and are abundant in nature. The advantages of the use of allylic alcohols over that of their derivatives such as allylic esters or carbonates are the high atom efficiency and the formation only of water as the by‐product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
First Chemical Synthesis, Aggregation Behavior and Cholesterol Solubilization Properties of Pythocholic Acid and 16α‐Hydroxycholic Acid
Authors: Nonappa  , Maitra Uday 
Published: May 2007

AbstractThe first chemical synthesis of pythocholic acid, a major component of python's bile, and 3α,7α,12α,16α‐tetrahydroxy‐5β‐cholan‐24‐oic acid (16α‐hydroxycholic acid), a minor component in Shoebill stork's bile, was achieved starting from readily available cholic acid in overall yields of 5 % and 5.5 %, respectively, through a common intermediate. A biomimetic template‐directed remote functionalization strategy was utilized to selectively functionalize C‐16 of the steroid skeleton. This synthesis involves a series of regio and chemoselective transformations. Pythocholic acid showed unusually low critical micellar concentration (CMC) with high cholesterol solubilization ability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Majority versus minority influence: the role of message processing in determining resistance to counter‐persuasion
Authors: Martin Robin , Hewstone Miles , Martin Pearl Y. 
Published: May 2007

AbstractTwo experiments examined the extent to which attitudes changed following majority and minority influence are resistant to counter‐persuasion. In both experiments participants' attitudes were measured after being exposed to two messages, delayed in time, which argued opposite positions (initial message and counter‐message). In the first experiment, attitudes following minority endorsement of the initial message were more resistant to a second counter‐message only when the initial message contained strong versus weak arguments. Attitudes changed following majority influence did not resist the second counter‐message and returned to their pre‐test level. Experiment 2 varied whether memory was warned (i.e., message recipients expected to recall the message) or not, to manipulate message processing. When memory was warned, which should increase message processing, attitudes changed following both majority and minority influence resisted the second counter‐message. The results support the view that minority influence instigates systematic processing of its arguments, leading to attitudes that resist counter‐persuasion. Attitudes formed following majority influence yield to counter‐persuasion unless there is a secondary task that encourages message processing. Copyright © 2007 John Wiley & Sons, Ltd.
Label‐Free Impedance Biosensors: Opportunities and Challenges
Authors: Daniels Jonathan S. , Pourmand Nader 
Published: May 2007

AbstractImpedance biosensors are a class of electrical biosensors that show promise for point‐of‐care and other applications due to low cost, ease of miniaturization, and label‐free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label‐free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label‐free impedance biosensors and identify areas for future research.
Preparation of Three‐Dimensional Ordered Macroporous Prussian Blue Film Electrode for Glucose Biosensor Application
Authors: Qiu Jian‐Ding , Peng Hong‐Zhen , Liang Ru‐Ping , Xiong Meng 
Published: May 2007

AbstractOrdered 3D interconnected macroporous Prussian blue (PB) films were electrochemically fabricated by using colloidal crystals of polystyrene beads as sacrificial templates. The prepared PB film electrodes have excellent catalytic activity towards the reduction of hydrogen peroxide. The PB structure was further used as functional interface for fabricating an enzyme‐based glucose sensor by using surface modification technique based on the electrostatic interactions. The resulted sensor has higher functional density, and larger surface area. The interconnected macroporous structure allows enhanced mass transport. These characteristics of the sensor enable us to detect glucose with high sensitivity. Therefore, the present 3D ordered macroporous film sensor exhibits wide linear detection range towards glucose, acceptable reproducibility and operational and storage stability. The present approach is promising for the generation of high‐enzyme‐content thin films with tailored bioactivity.
Electrochemistry and Electrocatalysis of a Nafion/Nano‐CaCO3/Hb Film Modified Carbon Ionic Liquid Electrode Using BMIMPF6 as Binder
Authors: Sun Wei , Gao Rui‐fang , Jiao Kui 
Published: May 2007

AbstractIn this paper a room temperature ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) was used as binder for the construction of carbon ionic liquid electrode (CILE) and a new electrochemical biosensor was developed for determination of H2O2 by immobilization of hemoglobin (Hb) in the composite film of Nafion/nano‐CaCO3 on the surface of CILE. The Hb modified electrode showed a pair of well‐defined, quasi‐reversible redox peaks with Epa and Epc as −0.265 V and −0.470 V (vs. SCE). The formal potential (E°′) was got by the midpoint of Epa and Epc as −0.368 V, which was the characteristic of Hb Fe(III)/Fe(II) redox couples. The peak to peak separation was 205 mV in pH 7.0 Britton–Robinson (B–R) buffer solution at the scan rate of 100 mV/s. The direct electrochemistry of Hb in the film was carefully investigated and the electrochemical parameters of Hb on the modified electrode were calculated as α=0.487 and ks=0.128 s−1. The Nafion/nano‐CaCO3/Hb film electrode showed good electrocatalysis to the reduction of H2O2 in the linear range from 8.0 to 240.0 μmol/L and the detection limit as 5.0 μmol/L (3σ). The apparent Michaelis–Menten constant (KMapp) was estimated to be 65.7 μmol/L. UV‐vis absorption spectroscopy and FT‐IR spectroscopy showed that Hb in the Nafion/nano‐CaCO3 composite film could retain its native structure.
Manganese Dioxide Graphite Composite Electrodes Formed via a Low Temperature Method: Detection of Hydrogen Peroxide, Ascorbic Acid and Nitrite
Authors: Šljukić Biljana , Compton Richard G. 
Published: May 2007

AbstractManganese dioxide modified carbon powder was prepared via a wet impregnation method from the solution of permanganate salt. After heating at 120 °C over night in air, the formation of manganese oxide was confirmed by cathodic stripping voltammetry. The synthesized material was used for fabrication of composite electrodes and their potential application in the field of electroanalysis investigated. The composite electrodes based on the manganese dioxide modified carbon powder proved to be useful as electrodes for detection of hydrogen peroxide, ascorbic acid and nitrite ions.
A Novel Glass Membrane for Low Temperature H2/O2Fuel Cell Electrolytes
Authors: Uma T. , Nogami M. 
Published: May 2007

AbstractA novel structure for an H2/O2fuel cell with a proton conducting glass electrolyte and a Pt/C catalyst was developed. The performance of the fuel cell, which was impregnated with a glass electrolyte and a gaseous hydrogen–oxygen feed at low temperature in a humidified atmosphere was significantly improved by introducing membrane electrode assemblies (MEAs) consisting of heteropolyacids (HPAs) (phosphotungstic acid, PWA and phosphomolybdic acid, PMA) doped with a P2O5‐SiO2glass electrolyte. The HPAs containing porous glass electrolytes show promise for applications in low temperature H2/O2fuel cells. The electrochemical behaviour of these materials was studied by measuring the current–voltage profile from polarisation curves. A maximum power density of ≈ 35 mW cm–2was obtained at 30 °C and 30% RH (relative humidity) using a PMA/PWA‐P2O5‐SiO2glass electrolyte membrane. The impedance measurements displaying the total cell ohmic resistance for 12 h at 0.5 V were evaluated at 30 °C. The resistance value was 3.5 Ω for an operating time of 12 h. This MEA showed the best and the most stable performance for use in an H2/O2fuel cell.
A hierarchical model for estimating significance levels of non‐parametric linkage statistics for large pedigrees
Authors: Brock Guy N. , Weeks Daniel E. , Sobel Eric , Feingold Eleanor 
Published: May 2007

AbstractThe significance level of a non‐parametric linkage (NPL) statistic is often found by simulation since the distribution of the test statistic is complex and unknown. Ideally, simulation occurs by randomly assigning founder genotypes and then simulating meiotic events for the descendants in the pedigree, commonly referred to as ‘gene dropping’. The missing data pattern in the original pedigree, including lack of phase information (due to unordered genotypes), is then imposed on the simulated pedigree. However, this approach is usually computationally infeasible for larger pedigrees which require Markov chain Monte Carlo (MCMC) techniques to calculate the statistic, as an additional MCMC run is required to estimate the statistic for each gene drop. In this work, we propose a novel method to estimate the significance level of the NPL statistic in large pedigrees. This is accomplished by constructing a hierarchical model, which allows estimation of the NPL statistic variability via separate estimation of the Markov chain and gene dropping variability. The significance level is estimated by fitting a parametric model to the statistic and using the method of moments to obtain parameter estimates. In a simulation study we found our hierarchical model estimates to be very close to the gold standard empirical estimates, and offer substantial improvements over the existing conservative method used by the software SimWalk2. The estimation procedure significantly reduces the computational time relative to the ideal empirical estimate, allowing for an accurate estimate of the significance level in a more manageable amount of time. Genet. Epidemiol. 31, 2007. © 2007 Wiley‐Liss, Inc.
A novel method to express SNP‐based genetic heterogeneity, Ψ, and its use to measure linkage disequilibrium for multiple SNPs, Dg, and to estimate absolute maximum of haplotype frequency
Authors: Yamada Ryo , Matsuda Fumihiko 
Published: May 2007

AbstractSingle nucleotide polymorphisms (SNPs) are important markers to investigate genetic heterogeneity of population and to perform linkage disequilibrium (LD) mapping. We propose a new method, Ψ, to express frequency of 2 haplotypes for Ns di‐allelic SNPs. Using the new expression of haplotype frequency, we propose a novel measure of LD, Dg, not only for SNP pairs but also for multiple markers. The values of Dg for SNP pairs were revealed to be similar to values of conventional pairwise LD indices, D′ and r2, and it was revealed that Dg quantitated components of LD that were not measured by conventional LD indices for SNP pairs. Also we propose a distinct method, Dg‐based absolute estimation, to infer the absolute maximum estimates of haplotype frequency. The result of the Dg‐based absolute estimation of haplotype frequency for SNP pairs were compared with the conventional expectation‐maximization (EM) algorithm and reported that the new method gave better inference than the EM algorithm which converged infrequently to a local extreme. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Exploring causality via identification of SNPs or haplotypes responsible for a linkage signal
Authors: Biernacka Joanna M. , Cordell Heather J. 
Published: May 2007

AbstractIn a small chromosomal region, a number of polymorphisms may be both linked to and associated with a disease. Distinguishing the potential causal sites from those indirectly associated due to linkage disequilibrium (LD) with a causal site is an important problem. This problem may be approached by determining which of the associations can explain the observed linkage signal. Recently, several methods have been proposed to aid in the identification of disease associated polymorphisms that may explain an observed linkage signal, using genotype data from affected sib pairs (ASPs) [Li et al. [2005] Am. J. Hum. Genet. 76:934–949; Sun et al. [2002] Am. J. Hum. Genet. 70:399–411]. These methods can be used to test the null hypothesis that a candidate single nucleotide polymorphism (SNP) is the sole causal variant in the region, or is in complete LD with the sole causal variant in the region. We extend variations of these methods to test for complete LD between a disease locus and haplotypes composed of two or more tightly linked candidate SNPs. We study properties of the proposed methods by simulation and apply them to type 1 diabetes data for ASPs and their parents at candidate SNP and microsatellite marker loci in the Insulin (INS) gene region. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Power of genome‐wide association studies in the presence of interacting loci
Authors: Pickrell Joseph , Clerget‐Darpoux Françoise , Bourgain Catherine 
Published: May 2007

AbstractThough multiple interacting loci are likely involved in the etiology of complex diseases, early genome‐wide association studies (GWAS) have depended on the detection of the marginal effects of each locus. Here, we evaluate the power of GWAS in the presence of two linked and potentially associated causal loci for several models of interaction between them and find that interacting loci may give rise to marginal relative risks that are not generally considered in a one‐locus model. To derive power under realistic situations, we use empirical data generated by the HapMap ENCODE project for both allele frequencies and linkage disequilibrium (LD) structure. The power is also evaluated in situations where the causal single nucleotide polymorphisms (SNPs) may not be genotyped, but rather detected by proxy using a SNP in LD. A common simplification for such power computations assumes that the sample size necessary to detect the effect at the tSNP is the sample size necessary to detect the causal locus directly divided by the LD measure r2 between the two. This assumption, which we call the “proportionality assumption”, is a simplification of the many factors that contribute to the strength of association at a marker, and has recently been criticized as unreasonable (Terwilliger and Hiekkalinna [2006] Eur J Hum Genet 14(4):426–437), in particular in the presence of interacting and associated loci. We find that this assumption does not introduce much error in single locus models of disease, but may do so in so in certain two‐locus models. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Comparison of admixture and association mapping in admixed families
Authors: Clarke Geraldine , Whittemore Alice S. 
Published: May 2007

AbstractThe family‐based admixture mapping test (AMT) identifies disease‐related genes using family data from admixed individuals with the disease of interest (cases). The cases' genotypes at a set of markers are used to infer their DNA ancestry as it varies in blocks along the chromosomes. The test compares the cases' inferred ancestries to those expected from their family histories. Deviation between observed and expected ancestries in a region suggests the presence of a disease gene. We use a likelihood‐based development of the AMT to compare it with the transmission disequilibrium test (TDT) as applied to admixed populations. The two tests have a common framework but differ significantly when the disease locus is untyped. The TDT infers disease‐locus genotypes using the markers with which it is in linkage disequilibrium (LD). In contrast, the AMT infers disease locus ancestries using those of its linked markers. Thus, TDT power depends on LD between disease and marker loci, while AMT power depends on the lengths of the ancestry blocks containing the disease locus. We compare the power of the two tests when applied to cases with descent from two ancestral populations. The AMT outperforms the TDT when case marker ancestries are correctly specified and LD between disease and marker loci is less than one‐third its maximal value (Δ′<1/3). However, the TDT performs better in the presence of uncertain marker ancestries, even for weak LD between disease and marker loci (Δ′ = 0.1). These findings have implications for the design of studies using admixed populations. Genet. Epidemiol. 31, 2007. © 2007 Wiley‐Liss, Inc.