bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microchips for CE: Breakthroughs in real‐world food analysis
Authors: Escarpa Alberto , González María Cristina , López Gil Miguel Angel , Crevillén Agustín G. , Hervás Miriam , García Miguel 
Published: January 2009

AbstractThe well‐known complexity of food matrices is approached using CE microchips with different strategies to improve the selectivity and sensitivity of the analysis by avoiding and/or making the sample preparation as simple as possible: (i) enhancing the peak capacity in order to perform direct injection, (ii) using the microchip platform to measure one target analyte/group of analytes with or without separating other related interferences, (iii) integrating sample preparation steps on the microchip platform, and (iv) integrating new analytical tools from nanotechnology in the detection stage. New analyte separations of food significance involving DNA probes, biogenic amines, vanilla flavors, and dyes have been reported as successfully breaking new barriers in areas of high impact in the market, such as transgenic food analysis, as well as the detection of frauds and toxins. Simple microchip layouts are still the most common designs used, though sophisticated new ones are emerging. In contrast to other application areas, electrochemical detection continues to be the most common detection route, followed by LIF, though non‐conventional detection routes are also emerging, such as chemiluminescence or UV. In terms of analytical performance, the integration of calibration and quality control on a microchip platform, and remarkable accuracy and precision are being obtained using creative analytical methodologies that enhance the analytical potency of microfluidic chips for their future commercialization. This review critically states the most important advances derived from work done in the field over the past 2–3 years.
A nanochannel‐based concentrator utilizing the concentration polarization effect
Authors: Huang Kuan‐Da , Yang Ruey‐Jen 
Published: January 2009

AbstractThis study develops a microfluidic device comprising two microchannels connected by a nanochannel in which the sample is concentrated via an ionic depletion effect. Using Rhodamine 6G dye for visualization purposes, it is shown that through an appropriate manipulation of the external potentials applied to the reservoirs of the device, an ionic depletion region with an electrical conductivity around 50 times lower than that of the buffer solution can be induced on the anodic side of the nanochannel. Furthermore, via an appropriate time‐based switching of the external electrical potentials, the sample species can be concentrated close to the conductivity ratio within an interval of 1 min. Finally, it is shown that by varying the configuration of the electrical potentials applied to the device reservoirs, the concentrated sample can be delivered either to a single outlet reservoir or to multiple reservoirs.
A novel, environmentally friendly sodium lauryl ether sulfate‐, cocamidopropyl betaine‐, cocamide monoethanolamine‐containing buffer for MEKC on microfluidic devices
Authors: Hoeman Kurt W. , Culbertson Christopher T. 
Published: January 2009

AbstractA new buffer has been developed for fast, high‐efficiency separations of amino acids by MEKC. This buffer was more environmentally friendly than the most commonly used surfactant‐containing buffers for MEKC separations. It used a commercially available dishwashing soap by Seventh Generation™ (Burlington, VT, USA), which contained three micelle‐forming agents. The mixed micelles were composed of sodium lauryl ether sulfate (anionic), cocamidopropyl betaine (zwitterionic), and cocamide monoethanolamine (non‐ionic). The optimized buffer contained 5.0% w/w Seventh Generation™ Free & Clear™ dishwashing soap, 10 mM sodium borate, and was completely void of organics. The lack of organics and the biodegradability of the surfactant molecules made this buffer more environmentally friendly than typical SDS‐containing buffers. This new buffer also had a different selectivity and provided faster separations with higher separation efficiencies than SDS‐based buffers. Fast separations of BODIPY FL labeled amino acids yielded peaks with separation efficiencies greater than 100 000 in less than 20 s.
Light at work: The use of optical forces for particle manipulation, sorting, and analysis
Authors: Jonáš Alexandr , Zemánek Pavel 
Published: January 2009

AbstractWe review the combinations of optical micro‐manipulation with other techniques and their classical and emerging applications to non‐contact optical separation and sorting of micro‐ and nanoparticle suspensions, compositional and structural analysis of specimens, and quantification of force interactions at the microscopic scale. The review aims at inspiring researchers, especially those working outside the optical micro‐manipulation field, to find new and interesting applications of these methods.
Microfluidic device for integrated restriction digestion reaction and resulting DNA fragment analysis
Authors: Xie Hua , Li Bowei , Zhong Runtao , Qin Jianhua , Zhu Yisheng , Lin Bingcheng 
Published: January 2009

AbstractA microfluidic system combining temperature‐controlled reactor, analyte delivery, chip electrophoresis (CE) separation, and fluorescence detection was developed, in which the heaters, resistance temperature detectors, enzymatic reactors, CE channels, and pneumatic valves/pumps were integrated onto a single glass–PDMS chip. The microdevice was used to perform the digestion reaction, followed by on‐line electrophoresis separation and detection of the resulting fragments with endonuclease BamHI and FokI as models. Pneumatic valves/pumps served not only for isolating the reaction region from the separation medium to prevent contamination, but also for delivering and quantitatively diluting the fluid from the reaction chamber to the CE section. Thus enzymatic reaction and electrophoresis separation could be insulated and connected as needed. A dynamic coating procedure with the use of PVP and mannitol was firstly adopted for glass–PDMS hybrid chip‐based DNA separations, leading to an improved separation efficiency with reproducible migration time and theoretical plates. The expected 263‐ and 287‐bp digestion products of BamHI and FokI were definitely verified by the size‐based electrophoretic separation and detection. The whole integrated reaction‐CE system can be manipulated in a simple manner with good reproducibility, which is expected to be applied in other on‐line analysis of various biochemical reactions.
Das Licht läuft auf zwei Beinen
Authors: Wegener Martin , Linden Stefan 
Published: January 2009

AbstractNanoklein und künstlich hergestellt: Metamaterialien bieten Forschern ungeahnte Möglichkeiten. Maßgeschneiderte „photonische Atome”︁ verhelfen ihnen zu neuen optischen Eigenschaften und inspirieren sie zu innovativen Anwendungen
Who knows more about future currency volatility?
Authors: Charoenwong Charlie , Jenwittayaroje Nattawut , Low Buen Sin 
Published: January 2009

AbstractWe use four currency pairs from October 1, 2001 to September 29, 2006 to compare the predictive power of the implied volatility derived from currency option prices that are traded on the Philadelphia Stock Exchange (PHLX), Chicago Mercantile Exchange (CME), and over‐the‐counter market (OTC). Among the competing implied volatility forecasts, OTC‐implied volatility subsumes the information content of PHLX‐ and CME‐implied volatility. Consistent with extant studies our result also shows that the implied volatility provides more information about future volatility–regardless of whether it is from the OTC, PHLX, or CME markets–than time series based volatility. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:270–295, 2009
Persistent mispricing in a recently opened emerging index futures market: Arbitrageurs invited
Authors: McMillan David G. , Ülkü Numan 
Published: January 2009

AbstractThe purpose of this study is to analyze the persistent, typically negative, mispricing in the new stock index futures market in Turkey, which has amounted to 5–8%, several multiples of transaction costs. The observations suggest that it is the outcome of a combination of practical difficulties of shorting in the spot stock market, behavioral effects, and insufficient arbitrage. The magnitude of the mispricing and the absence of arbitrage make behavioral effects more visible and provide a unique opportunity to examine extant behavioral hypotheses. Results confirm effects such as disposition and/or conservatism with the mispricing negatively related to past returns, but unrelated to future returns. Finally, an orderly weakening of the negative relation to past returns and behavioral effects is observed, suggesting that such effects will diminish as the market matures. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:218–243, 2009
Estimating error in measuring thermal conductivity using a T‐type nanosensor
Authors: Ito Yohei , Takahashi Koji , Fujii Motoo , Zhang Xing 
Published: January 2009

AbstractWe discuss the measurement error caused by fabrication and measurement of a T‐type nanosensor with a suspended sub‐micrometer Pt hot film that was developed to measure the thermal properties of individual nanowire materials. Comparison of numerical simulation and one‐dimensional analysis revealed that the thermal conductivity of nanowire material such as a carbon nanotube is calculated to be 17% lower. As an example, the thermal conductivity measurement result for a SiC nanowire is reported. The error caused by contact thermal resistance is found to depend on the contact length and can be as great as 20%. It can be said that future measuring can have higher reliability by correcting the estimated measurement error. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20228
A lubricious formulation exhibiting reduced thrombogenicity, cell proliferation, and protein adsorption
Authors: Vicario Pasquale P. , Lu Zichun J. , Grigorian Irina A. , Schottman Tom 
Published: January 2009

AbstractThe adhesion of human platelets, erythrocytes, and leukocytes, the adsorption of protein, and the proliferation of human umbilical vein endothelial cells (HUVEC) on the surface of electropolished stainless steel and the lumen of polyurethane tubing coated with Hydromer's lubricious Duality™ T8B formulation was evaluated. Following exposure to a platelet‐enriched suspension from citrated human whole blood, stainless steel coated with this formulation exhibited significantly reduced adhesion of platelets, erythrocytes, and granulocytes. This reduction in adhesion was confirmed using an immunohistochemical method utilizing antibodies to CD41, CD235, and CD15, respectively. The proliferation of HUVEC cells were significantly reduced when cultured on coated stainless steel. This formulation was also able to significantly reduce the adsorption of plasma proteins and the major protein in tear fluid (lysozyme) to the surface of stainless steel. The nonthrombogenic properties of Duality™ T8B after application to the lumen of polyurethane tubing were also examined. Following a short‐term (3 h) static exposure to citrated human whole blood, microscopic examination revealed that the adhesion of platelets and erythrocytes was reduced significantly, a finding confirmed using anti‐CD41 and anti‐CD235 antibodies in the immunohistochemical method. A long‐term (12 day) study yielded essentially identical results indicating a significant reduction in the adhesion of blood components on the luminal surface of coated polyurethane tubing. In summary, these data indicate that the application of Duality™ T8B onto surfaces of medical devices, such as catheters, extracorporeal circuitry, and coronary stents, could aid in reducing or preventing not only thrombus formation but also the process of restenosis. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Stem cell sources to treat diabetes
Authors: Furth Mark E. , Atala Anthony 
Published: January 2009

AbstractWe review progress towards the goal of utilizing stem cells as a source of engineered pancreatic β‐cells for therapy of diabetes. Protocols for the in vitro differentiation of embryonic stem (ES) cells based on normal developmental cues have generated β‐like cells that produce high levels of insulin, albeit at low efficiency and without full responsiveness to extracellular levels of glucose. Induced pluripotent stem (iPS) cells also can yield insulin‐producing cells following similar approaches. An important recent report shows that when transplanted into mice, human ES‐derived cells with a phenotype corresponding to pancreatic endoderm matured to yield cells capable of maintaining near‐normal regulation of blood sugar [Kroon et al., 2008]. Major hurdles that must be overcome to enable the broad clinical translation of these advances include teratoma formation by ES and iPS cells, and the need for immunosuppressive drugs. Classes of stem cells that can be expanded extensively in culture but do not form teratomas, such as amniotic fluid‐derived stem cells and hepatic stem cells, offer possible alternatives for the production of β‐like cells, but further evidence is required to document this potential. Generation of autologous iPS cells should prevent transplant rejection, but may prove prohibitively expensive. Banking strategies to identify small numbers of stem cell lines homozygous for major histocompatibility loci have been proposed to enable beneficial genetic matching that would decrease the need for immunosuppression. J. Cell. Biochem. 106: 507–511, 2009. © 2009 Wiley‐Liss, Inc.
High expression of apolipoprotein E impairs lipid storage and promotes cell proliferation in human adipocytes
Authors: Carmel Jean‐François , Tarnus Evelyne , Cohn Jeffrey S. , Bourdon Emmanuel , Davignon Jean , Bernier Lise 
Published: January 2009

AbstractApolipoprotein E (apoE), a key regulator of lipid metabolism, is highly produced by adipose tissue and adipocytes. However, there is little information about its role on adipocyte functions. Because apoE‐deficiency in adipocytes was shown to impair adipocyte differentiation, we investigated the consequences of apoE high expression on differentiation and proliferation of a human adipocytic cell line (SW872). SW872 cells were transfected with human apoE to induce a fivefold increase in apoE production and secretion. Adipocyte differentiation and proliferation were assayed by measuring lipid content, adipogenic gene expression, cell number, cell resistance to serum deprivation, and cell division kinetics. Cultured apoE‐transfected cells accumulated less triglycerides and less cholesterol than control cells. This decrease in lipid accumulation was associated with a strong downregulation of peroxisome proliferator‐activated receptors γ1 and γ2 and stearoyl‐CoA desaturase 1. The decrease in lipid accumulation was not dependent on the presence of lipids, lipoproteins, or PPAR‐γ agonists in the culture medium, nor was it observed with exogenously added apoE. Moreover, we observed that apoE‐transfected cells were more resistant to death induced by serum deprivation, and that these cells underwent more cell divisions than control cells. These results bring new evidence of apoE‐involvement in metabolic disorders at the adipocyte level. J. Cell. Biochem. 106: 608–617, 2009. © 2009 Wiley‐Liss, Inc.
A new iterative linear integral isoconversional method for the determination of the activation energy varying with the conversion degree
Authors: Cai Junmeng , Chen Siyu 
Published: January 2009

AbstractThe conventional linear integral isoconversional methods may lead to important errors in the determination of the activation energy when the significant variation of the activation energy with the conversion degree occurs. Vyazovkin proposed an advanced nonlinear isoconversional method, which allows the activation energy to be accurately determined [Vyazovkin, J Comput Chem 2001, 22, 178]. However, the use of the Vyazovkin method raises the problem of the time‐consuming minimization without derivatives. A new iterative linear integral isoconversional method for the determination of the activation energy as a function of the conversion degree has been proposed, which is capable of providing valid values of the activation energy even if the latter strongly varies with the conversion degree. Also, the new method leads to the correct values of the activation energy in much less time than the Vyazovkin method. The application of the new method is illustrated by processing of theoretically simulated data of a strongly varying activation energy process. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009
Optimization of bimetallic Cu–Au and Ag–Au clusters by using a modified adaptive immune optimization algorithm
Authors: Wu Xia , Cai Wensheng , Shao Xueguang 
Published: January 2009

AbstractA modified adaptive immune optimization algorithm (AIOA) is designed for optimization of Cu–Au and Ag–Au bimetallic clusters with Gupta potential. Compared with homoatom clusters, there are homotopic isomers in bimetallic cluster, so atom exchange operation is presented in the modified AIOA. The efficiency of the algorithm is tested by optimization of CunAu38‐n (0 ≤ n ≤ 38). Results show that all the structures with the putative global minimal energies are successfully located. In the optimization of AgnAu55‐n (0 ≤ n ≤ 55) bimetallic clusters, all the structures with the reported minimal energies are obtained, and 36 structures with even lower potential energies are found. On the other hand, with the optimized structures of CunAu55‐n, it is shown that all 55‐atom Cu–Au bimetallic clusters are Mackay icosahedra except for Au55, which is a face‐centered cubic (fcc)‐like structure; Cu55, Cu12Au43, and Cu1Au54 have two‐shell Mackay icosahedral geometries with Ih point group symmetry. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009
Haptic quantum chemistry
Authors: Marti Konrad H. , Reiher Markus 
Published: January 2009

AbstractWe present an implementation designed to physically experience quantum mechanical forces between reactants in chemical reactions. This allows one to screen the profile of potential energy surfaces for the study of reaction mechanisms. For this, we have developed a interface between the user and a virtual laboratory by means of a force‐feedback haptic device. Potential energy surfaces of chemical reactions can be explored efficiently by rendering in the haptic device the gradients calculated with first‐principles methods. The underlying potential energy surface is accurately fitted on the fly by the interpolating moving least‐squares (IMLS) scheme to a grid of quantum chemical electronic energies (and geometric gradients). In addition, we introduce a new IMLS‐based method to locate minimum‐energy paths between two points on a potential energy surface. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009
Femtosecond electron diffraction: Direct probe of ultrafast structural dynamics in metal films
Authors: Nie Shouhua , Wang Xuan , Li Junjie , Clinite Richard , Cao Jianming 
Published: January 2009

AbstractFemtosecond electron diffraction is a rapidly advancing technique that holds a great promise for studying ultrafast structural dynamics in phase transitions, chemical reactions, and function of biological molecules at the atomic time and length scales. In this paper, we summarize our development of a tabletop femtosecond electron diffractometer. Using a delicate instrument design and careful experimental configurations, we demonstrate the unprecedented capability of detecting submilli‐ångström lattice spacing change on a subpicosecond timescale with this new technique. We have conducted an in‐depth investigation of ultrafast coherent phonon dynamics induced by an impulsive optical excitation in thin‐film metals. By probing both coherent acoustic and random thermal lattice motions simultaneously in real time, we have provided the first and unambiguous experimental evidence that the pressure of hot electrons contributes significantly to the generation of coherent acoustic phonons under nonequilibrium conditions when electrons and phonons are not thermalized. Based on these observations, we also propose an innovative approach to measure the electronic Grüneisen parameter in magnetic materials at and above room temperature, which provides a way to gain new insights into electronic thermal expansion in ferromagnetic transition metals. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
Kinetic measurements from in situ TEM observations
Authors: Sharma Renu 
Published: January 2009

AbstractEnvironmental transmission or scanning transmission electron microscope is ideally suited to observe gas solid interactions at nanoscale. It is shown that the time and temperature resolved data, obtained from in situ observations, can be used to obtain reaction rates and understand the kinetics of the processes. Low or high magnification images provide the change in length, area or volume with time at constant temperature and pressure conditions during nitridation of Cu–Cr thin films, deposition of Au particles, growth of Si nanowire and carbon nanotubes. Effect of electron beam is estimated by making observations with and without constant electron beam exposure. Quantitative electron energy loss spectroscopy is employed to measure the reduction rate of Ce+4 in pure ceria, mixed oxides (ceria‐zirconia) and catalyst (Rh‐ceria‐zirconia) powders. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
In situ TEM of radiation effects in complex ceramics
Authors: Lian Jie , Wang L.M. , Sun Kai , Ewing Rodney C. 
Published: January 2009

AbstractIn situ transmission electron microscopy (TEM) has been extensively applied to study radiation effects in a wide variety of materials, such as metals, ceramics and semiconductors and is an indispensable tool in obtaining a fundamental understanding of energetic beam‐matter interactions, damage events, and materials' behavior under intense radiation environments. In this article, in situ TEM observations of radiation effects in complex ceramics (e.g., oxides, silicates, and phosphates) subjected to energetic ion and electron irradiations have been summarized with a focus on irradiation‐induced microstructural evolution, changes in microchemistry, and the formation of nanostructures. New results for in situ TEM observation of radiation effects in pyrochlore, A2B2O7, and zircon, ZrSiO4, subjected to multiple beam irradiations are presented, and the effects of simultaneous irradiations of α‐decay and β‐decay on the microstructural evolution of potential nuclear waste forms are discussed. Furthermore, in situ TEM results of radiation effects in a sodium borosilicate glass subjected to electron‐beam exposure are introduced to highlight the important applications of advanced analytical TEM techniques, including Z‐contrast imaging, energy filtered TEM (EFTEM), and electron energy loss spectroscopy (EELS), in studying radiation effects in materials microstructural evolution and microchemical changes. By combining ex situ TEM and advanced analytical TEM techniques with in situ TEM observations under energetic beam irradiations, one can obtain invaluable information on the phase stability and response behaviors of materials under a wide range of irradiation conditions. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.