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Selected AbstractsNeutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2006,2007GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 4 2008L. Paul Bédard These mature analytical techniques do not show any change in publication level from the previous two years and AAS remains dominant in terms of the number of publications. The last two years have seen fewer technical improvements than in the previous review period. Some interesting papers dealing with uncertainty and quality assurance in INAA were published during 2006,2007. It is suggested that photon activation should be reconsidered because the source of electron accelerators has recently improved. A technique to preconcentrate Se for INAA determination has also been proposed. In the case of AAS, papers on analyte preconcentration continue to be more abundant than those relating to instrumental modification. Sample preparation for AAS is also active and ultrasound-assisted leaching shows some promising applications. There were an unusual number of reviews concerned with AAS and those important to geological samples are cited here. A technique to preconcentrate Cr in water is presented and a new device to determine As and Se is showing some potential uses. Confocal X-ray mapping continues to show interesting developments. One group developed a technique to perform XRF inside an oyster and an interesting application of ,-XRF mapping of sediments is presented. Determination of platinum-group elements (at ,g g1 concentrations) can be carried out very quickly with an improved XRF technique. [source] Feature-space clustering for fMRI meta-analysis,HUMAN BRAIN MAPPING, Issue 3 2001Cyril Goutte Abstract Clustering functional magnetic resonance imaging (fMRI) time series has emerged in recent years as a possible alternative to parametric modeling approaches. Most of the work so far has been concerned with clustering raw time series. In this contribution we investigate the applicability of a clustering method applied to features extracted from the data. This approach is extremely versatile and encompasses previously published results [Goutte et al., 1999] as special cases. A typical application is in data reduction: as the increase in temporal resolution of fMRI experiments routinely yields fMRI sequences containing several hundreds of images, it is sometimes necessary to invoke feature extraction to reduce the dimensionality of the data space. A second interesting application is in the meta-analysis of fMRI experiment, where features are obtained from a possibly large number of single-voxel analyses. In particular this allows the checking of the differences and agreements between different methods of analysis. Both approaches are illustrated on a fMRI data set involving visual stimulation, and we show that the feature space clustering approach yields nontrivial results and, in particular, shows interesting differences between individual voxel analysis performed with traditional methods. Hum. Brain Mapping 13:165,183, 2001. © 2001 Wiley-Liss, Inc. [source] APPLICATION OF TWO CONSUMER PROFILING TECHNIQUES TO COSMETIC EMULSIONSJOURNAL OF SENSORY STUDIES, Issue 5 2010MARÍA EMMA PARENTE ABSTRACT The sensory characteristics of cosmetic products are commonly used for attracting consumers' attention in advertising campaigns and packaging. Thus, in order to appropriately satisfy consumers' sensory expectations, it is important to gather information about their perception of the sensory characteristics. In this context, the aim of the present work was to apply two consumer methodologies (intensity scales and a check-all-that-apply [CATA] question) to gather information about the sensory profile of cosmetic emulsions. Six cosmetic emulsions with different formulation, widely differing in their sensory characteristics, were evaluated by two groups of 50 female consumers. One group used intensity scales to evaluate eight attributes of the emulsions and the other completed a CATA question comprising 20 terms related to sensory characteristics of the emulsions, cosmetic applications and effects on the skin. Both intensity scales and CATA question were able to detect differences in consumers' perception of the sensory characteristics of the evaluated emulsions. These differences could be explained considering the samples' formulation, which suggests their validity and indicates that they could consist on interesting alternatives to traditional sensory profiles obtained with trained assessors' panels. PRACTICAL APPLICATIONS The application of intensity scales or a CATA question consisted of an interesting approach to gather information about consumers' perception of cosmetic products. Despite both methodologies provided similar results, the application of CATA questions could be regarded as more natural for consumers and easier to use. Besides, CATA questions could enable the identification of consumers' perception of the sensory characteristics of cosmetic products, but also their effects on the skin and the cosmetic applications for which they are considered appropriate. An interesting application of this methodology could be the development of a line of cosmetic products with different applications or the selection of sensory and efficacy claims during the design of marketing strategies or labels of cosmetic products. [source] New implementation of a SNOM suitable to study topographical features over wide areasPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2005A. Ustione Abstract A new implementation of a SNOM is described, aiming at the topographical study of large areas and exploiting the advantages of the shear-force detection system. This technique finds very interesting application in the study of archeological or artistic samples, where it often occurs that an area to be examined at high resolution (optically, topographically or chemically) is enclosed in a wider one. The implemented system allows to obtain scans of wide areas by using dc-motors to move the sample under the probe tip, and thus it can face rough samples with height differences of several tens of micrometers. It allows the user to choose whether to use the SNOM to study the optical and topographical properties of a small part of the sample (up to tens of square micrometers), or to use the motor-driven scan technique, to study the topographical characteristic of a large area of the sample (up to some square millimeters) and even over rough surfaces. We show results detecting worn relieves over a coin. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electroanalysis at Diamond-Like and Doped-Diamond ElectrodesELECTROANALYSIS, Issue 17 2003Richard Abstract Diamond as a high performance material occupies a special place due to its in many ways extreme properties, e.g., hardness, chemical inertness, thermal conductivity, optical properties, and electric characteristics. Work mainly over the last decade has shown that diamond also occupies a special place as an electrode material with interesting applications in electroanalysis. When made sufficiently electrically conducting for example by boron-doping, ,thin film' and ,free,standing' diamond electrodes exhibit remarkable chemical resistance to etching, a wide potential window, low background current responses, mechanical stability towards ultrasound induced interfacial cavitation, a low ,stickiness' in adsorption processes, and a high degree of ,tunability' of the surface properties. This review summarizes some of the recent work aimed at applying conductive (boron-doped) diamond electrodes to improve procedures in electroanalysis. [source] Separation of multiphosphorylated peptide isomers by CZEELECTROPHORESIS, Issue 21 2008Marika V. Muetzelburg Abstract A separation of mono, doubly and triply phosphorylated isomers was developed with CZE with an aqueous electrolyte containing 3.9,mol/L formic acid and 30%,v/v trifluoroethanol. Thus a mixture of ten phosphopeptides corresponding to the human tau sequence 226,240 was separated within 70,min. Although peptides with different phosphorylation degrees, i.e. 0,3 phosphate groups, were well separated, some of the phosphopeptide isomers containing one or two phosphate groups were only partially separated. The electrolyte system is compatible with both MALDI- and ESI-MS, allowing a direct coupling, and thus could have some interesting applications in proteomics. [source] Recent Developments in Synthetic Chemistry, Chiral Separations, and Applications of Tröger's Base AnaloguesHELVETICA CHIMICA ACTA, Issue 3 2009Sergey Sergeyev Abstract Tröger's base is a well-known chiral molecule with a few unusual structural features. The chemistry of Tröger's base analogues has been greatly developed over the last 20 years, and numerous interesting applications in supramolecular chemistry and in molecular recognition have emerged. This Review gives a short overview of the chemistry of Tröger's base and its analogues, with particular focus on recent achievements in synthesis, enantiomer separations, and applications. [source] A two-dimensional stochastic algorithm for the solution of the non-linear Poisson,Boltzmann equation: validation with finite-difference benchmarks,INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2006Kausik Chatterjee Abstract This paper presents a two-dimensional floating random walk (FRW) algorithm for the solution of the non-linear Poisson,Boltzmann (NPB) equation. In the past, the FRW method has not been applied to the solution of the NPB equation which can be attributed to the absence of analytical expressions for volumetric Green's functions. Previous studies using the FRW method have examined only the linearized Poisson,Boltzmann equation. No such linearization is needed for the present approach. Approximate volumetric Green's functions have been derived with the help of perturbation theory, and these expressions have been incorporated within the FRW framework. A unique advantage of this algorithm is that it requires no discretization of either the volume or the surface of the problem domains. Furthermore, each random walk is independent, so that the computational procedure is highly parallelizable. In our previous work, we have presented preliminary calculations for one-dimensional and quasi-one-dimensional benchmark problems. In this paper, we present the detailed formulation of a two-dimensional algorithm, along with extensive finite-difference validation on fully two-dimensional benchmark problems. The solution of the NPB equation has many interesting applications, including the modelling of plasma discharges, semiconductor device modelling and the modelling of biomolecular structures and dynamics. Copyright © 2005 John Wiley & Sons, Ltd. [source] Protein thermal stability and phospholipid,protein interaction investigated by capillary isoelectric focusing with whole column imaging detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2006Tao Bo Abstract CIEF with whole column imaging detection (WCID) is an attractive technique for studying protein reaction and protein,ligand interaction due to its fast separation, simple operation, and high efficiency. In this study, two interesting applications by the CIEF-WCID were developed, involving the study of protein thermal stability and phospholipid,protein interaction. Four proteins (,-lactoglobulin B, trypsin inhibitor, phosphorylase b, and trypsinogen) with different pI, and two types of phospholipids, including phosphatidylcholine (PC) and phosphatidylserine (PS), were used for this purpose. First, the altered CIEF profiles of four proteins were exhibited due to conformational changes resulting from protein denaturation induced by a high incubation temperature at 60°C. It was demonstrated that the addition of a zwitterionic phospholipid (PC) played a crucial role in the thermal stability of targeted proteins, especially for trypsin inhibitor whose thermal stability was promoted with the addition of the PC vesicles at 60°C. Second, the zwitterionic (PC) and acidic (PS) phospholipids displayed completely different interactions with the proteins. The addition of PS vesicles modified the zwitterionic phospholipids to carry negative charges, which correspondingly changed the interaction between the phospholipid and the protein. Our study demonstrates that the CIEF-WCID is a powerful approach to study protein reaction and protein,ligand interaction with high efficiency, high selectivity, and fast separation. [source] Magnetic resonance imaging of the skinJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 8 2010J Stefanowska Abstract A thorough examination of the skin is essential to screen various diseases accurately, evaluate the effectiveness of topically applied drugs and assess the results of dermatological surgeries such as skin grafts. The assessment of skin properties is also crucial in the cosmetics industry, where it is important to evaluate the effects skin care products have on these properties. The simplest and most widely used method of skin evaluation, the ,naked eye' assessment, enables researchers to assess only the skin surface and involves a large amount of inter-observer variability. Thanks to a great progress that has been made in physics, electronics and computer engineering in recent years, sophisticated imaging methods are increasingly available in day-to-day studies. The aim of this review was to present one of these techniques, namely the magnetic resonance imaging (MRI), and to discuss its possible use in skin examination and analysis. We present basic principles of MRI, as well as several interesting applications in the field of dermatology, and discuss the advantages and limitations of this method. [source] Physico-enzymatic production of monoacylglycerols enriched with very-long-chain polyunsaturated fatty acidsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2008Ratchapol Pawongrat Abstract BACKGROUND: Monoacylglycerols (MAG) containing polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have interesting applications. The enzymatic processing of such MAG directly from fish oils is highly interesting, integrating the processing of MAG and concentration of EPA and DHA. The aim of this study was to develop an efficient enzymatic glycerolysis system together with physical fractionation for the production of PUFA-MAG from tuna oil. RESULTS: Novozym 435 was eventually selected after evaluation together with immobilized lipase AK in a tertiary alcohol-based system. A further evaluation of solvent mixtures involving tertiary alcohols was made, taking ease of operation into consideration. It turned out that a number of mixtures gave a similar performance to that of tert -butanol (TB). Basic reaction parameters were thoroughly evaluated. In the batch reaction system with TB as solvent, the recommended conditions were: glycerol/tuna oil 4:1 (mol/mol), TB/tuna oil 2:1 (wt/wt), 15 wt% Novozym 435, and temperature 40 °C. Under these conditions, the yield of MAG was up to 90% after 3 h incubation. Crude MAG from the production was fractionated to produce MAG with higher EPA and DHA content. Using acetone as solvent at 0 °C led to ca 50% yield of MAG but contained EPA and DHA up to 71% in comparison with ca 30% in tuna oil. CONCLUSION: Potentially practical process steps have been developed for the production of MAG containing a high content of EPA and DHA from natural fish oils with high efficiency and simplicity. Copyright © 2007 Society of Chemical Industry [source] Growth and properties of nanocrystalline diamond filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 13 2006Oliver A. Williams Abstract The aim of this paper is to summarise recent progress in the growth of small grain-sized Chemical Vapor Deposition (CVD) diamond often called nanocrystalline diamond, i.e., diamond with grains typically smaller than 500 nm. Nanocrystalline (NCD) and Ultrananocrystalline diamond (UNCD) films are new materials offering interesting applications to nanobioelectronics and electrochemistry. However NCD and UNCD thin films comprise of entirely different structures which is highlighted here in this paper. We discuss in detail the main differences in Raman spectra, optical properties and electrical transport properties. Finally we present a simple model of the conductivity mechanism in nitrogenated UNCD (N-UNCD) and boron doped NCD (B-NCD) films, and show the possibility of achieving the superconductive transition in B-NCD films. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Trend derivatives: Pricing, hedging, and application to executive stock optionsTHE JOURNAL OF FUTURES MARKETS, Issue 2 2007Markus Leippold Both institutional and private investors often have only limited flexibility in timing their investment decision. They look for investments that will ideally be independent of the timing decision. In this article, a new class of derivative products whose payoff is linked to the trend of the underlying instrument is introduced. By linking the trend to the payoff, the timing of the decision becomes less important. Therefore, trend derivatives offer some time-diversification benefits. How trend derivatives are designed and priced is shown. Due to their peculiar features, trend derivatives offer some interesting applications such as executive stock option plans. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:151,186, 2007 [source] Novel properties of wave propagation in biaxially anisotropic left-handed materialsANNALEN DER PHYSIK, Issue 6 2004J.Q. Shen Abstract Some physically interesting properties and effects (including the quantum effects) of wave propagation in biaxially anisotropic left-handed materials are investigated in this paper: (i) we show that in the biaxially gyrotropic left-handed material, the left-right coupling of circularly polarized light arises due to the negative indices in permittivity and permeability tensors of gyrotropic media; (ii) it is well known that the geometric phases of photons inside a curved fiber in previous experiments often depend on the cone angles of solid angles subtended by a curve traced by the direction of wave vector of light, at the center of photon momentum space. Here, however, for the light propagating inside certain anisotropic left-handed media we will present a different geometric phase that is independent of the cone angles; (iii) the extra phases of electromagnetic wave resulting from the instantaneous helicity inversion at the interfaces between left- and right-handed (LRH) media is also studied in detail by using the Lewis-Riesenfeld invariant theory. Some interesting applications (e.g., controllable position-dependent frequency shift, detection of quantum-vacuum geometric phases and helicity reversals at the LRH interfaces etc.) of above effects and phenomena in left-handed media is briefly discussed. [source] Preferred Functionalization of Metallic and Small-Diameter Single-Walled Carbon Nanotubes by Nucleophilic Addition of Organolithium and -Magnesium Compounds Followed by ReoxidationCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2008David Wunderlich Dipl.-Chem Abstract Covalent sidewall addition to single-walled nanotubes (SWNTs) of a series of organolithium and organomagnesium compounds (nBuLi, tBuLi, EtLi, nHexLi, nBuMgCl, tBuMgCl) followed by reoxidation is reported. The functionalized Rn -SWNTs were characterized by Raman and NIR emission spectroscopy. The reaction of SWNTs with organolithium and magnesium compounds exhibits pronounced selectivity: in general, metallic tubes are more reactive than semiconducting ones. The reactivity of SWNTs toward the addition of organometallic compounds is inversely proportional to the diameter of the tubes. This was determined simultaneously and independently for both metallic and semiconducting SWNTs. The reactivity also depends on the steric demands of the addend. Binding of the bulky t- butyl addend is less favorable than addition of primary alkyl groups. Significantly, although tBuLi is less reactive than, for example, nBuLi, it is less selective toward the preferred reaction with metallic tubes. This unexpected behavior is explained by fast electron transfer to the metallic SWNTs having low-lying electronic states close to the Fermi level, a competitive initial process. The NIR emission of weakly functionalized semiconducting SWNTs, also reported for the first time, implies interesting applications of functionalized tubes as novel fluorescent reporter molecules. [source] Symplectic rigidity, symplectic fixed points, and global perturbations of Hamiltonian systemsCOMMUNICATIONS ON PURE & APPLIED MATHEMATICS, Issue 3 2008Dragomir L. Dragnev In this paper we study a generalized symplectic fixed-point problem, first considered by J. Moser in [20], from the point of view of some relatively recently discovered symplectic rigidity phenomena. This problem has interesting applications concerning global perturbations of Hamiltonian systems. © 2007 Wiley Periodicals, Inc. [source] |