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The in vivo and in vitro metabolism and the detectability in urine of 3’,4’‐methylenedioxy‐alpha‐pyrrolidinobutyrophenone (MDPBP), a new pyrrolidinophenone‐type designer drug, studied by GC‐MS and LC‐MS n
Published: Oct 7, 2013
Author(s): Markus R. Meyer, Sandra Mauer, Golo M. J. Meyer, Julia Dinger, Birgit Klein, Folker Westphal, Hans H. Maurer
Journal: Drug Testing and Analysis
3’,4’‐Methylenedioxy‐alpha‐pyrrolidinobutyrophenone (MDPBP), a designer drug of the pyrrolidinophenone‐type, was first seized in Germany in 2009. It was also identified in ‘legal high’ samples investigated in the UK. Therefore, the aim of the presented work was to identify its in vivo and in vitro phase I and II metabolites using gas chromatography‐mass spectrometry (GC‐MS) and liquid chromatography‐ion trap mass spectrometry (LC‐MSn)....
Read MoreDFT study and quantitative detection by surface‐enhanced Raman scattering (SERS) of ethyl carbamate
Published: Oct 7, 2013
Author(s): Danting Yang, Nicoleta E. Mircescu, Haibo Zhou, Nicolae Leopold, Vasile Chiş, Mircea Oltean, Yibin Ying, Christoph Haisch
Journal: Journal of Raman Spectroscopy
Ethyl carbamate (EC), a potentially toxic compound, is found in alcoholic beverages and fermented foodstuff. A combined experimental and theoretical study of Raman on EC is reported in this work for the first time. The Raman bands observed for EC in solid phase are characteristic for the carbonyl group, C―C, C―H and N―H stretching and deformation vibrations. These spectral features coupled with a pKa study allowed establishing the neutral...
Read MoreChemistry and morphology of dried‐up pollen suspension residues
Published: Oct 7, 2013
Author(s): Bernhard G. Pummer, Heidi Bauer, Johannes Bernardi, Bertrand Chazallon, Sébastien Facq, Bernhard Lendl, Karin Whitmore, Hinrich Grothe
Journal: Journal of Raman Spectroscopy
Pollen grains are covered with lots of different biochemical compounds, like proteins, saccharides and lipids, which are only loosely attached to the pollen. Therefore, they can be separated from the pollen by suspending them in water. Since these compounds play a key role in many atmospheric processes (e.g. cloud condensation nucleation, ice nucleation, aerial allergen exposure), their separation and analyzing are of interest. ...
Read MoreSurface functionalized thiol‐ene waveguides for fluorescence biosensing in microfluidic devices
Published: Oct 7, 2013
Author(s): Nikolaj A. Feidenhans'l, Josiane P. Lafleur, Thomas G. Jensen, Jörg P. Kutter
Journal: ELECTROPHORESIS
Thiol‐ene polymers possess physical, optical, and chemical characteristics that make them ideal substrates for the fabrication of optofluidic devices. In this work, thiol‐ene polymers are used to simultaneously create microfluidic channels and optical waveguides in one simple moulding step. The reactive functional groups present at the surface of the thiol‐ene polymer are subsequently used for the rapid, one step, site‐specific...
Read MoreScattering detection using a photonic‐microfluidic integrated device with on‐chip collection capabilities
Published: Oct 7, 2013
Author(s): Benjamin R. Watts, Zhiyi Zhang, Chang Qing Xu, Xudong Cao, Min Lin
Journal: ELECTROPHORESIS
SU‐8‐based photonic‐microfluidic integrated devices with on‐chip beam shaping and collection capabilities were demonstrated in a scattering detection and counting application. Through the proper deployment of the tailored beam geometries via the on‐chip excitation optics, excellent CV values were measured for 1, 2, and 5 μm blank beads, 16.4, 11.0, and 12.5%, respectively, coupled with a simple free‐space optical detection scheme. The...
Read MoreA rapid, straightforward, and print house compatible mass fabrication method for integrating 3D paper‐based microfluidics
Published: Oct 7, 2013
Author(s): Liangpin Xiao, Xianming Liu, Runtao Zhong, Kaiqing Zhang, Xiaodi Zhang, Xiaomian Zhou, Bingcheng Lin, Yuguang Du
Journal: ELECTROPHORESIS
Three‐dimensional (3D) paper‐based microfluidics, which is featured with high performance and speedy determination, promise to carry out multistep sample pretreatment and orderly chemical reaction, which have been used for medical diagnosis, cell culture, environment determination, and so on with broad market prospect. However, there are some drawbacks in the existing fabrication methods for 3D paper‐based microfluidics, such as,...
Read MoreSynthesis, characterization, and application of silver nanoparticle‐thiophenol nanocomposite film on the glassy carbon surface
Published: Oct 7, 2013
Author(s): Remziye Güzel, Haslet Ekşi, Zafer Üstündağ, Ali Osman Solak
Journal: Surface and Interface Analysis
In this study, 4‐thiophenol modified glassy carbon electrode was prepared by the reduction of 4‐diazothiophenol tetrafluoroborate salt. Silver nanoparticles were attached to the thiophenol modified surface to prepare a thiophenol‐silver nanoparticle composite film. 4‐Aminothiopenol molecules were deposited by self‐assembling technique to form multi‐layered nanofilms of TP/SNP/PhNH2 on glassy carbon substrate. These surfaces were characterized by...
Read MoreCharacterizing multivariate calibration tradeoffs (bias, variance, selectivity, and sensitivity) to select model tuning parameters
Published: Oct 6, 2013
Author(s): John H. Kalivas, Jon Palmer
Journal: Journal of Chemometrics
Common methods used to form multivariate calibration models are partial least squares, principal component regression, and ridge regression. There are many aspects to forming a calibration model. The focus in this paper is determining “good” values of respective meta‐parameters (tuning parameters). In most situations, some form of cross‐validation and the resultant root mean square error of cross‐validation (RMSECV) values are evaluated....
Read MoreA novel fusion approach based on induced ordered weighted averaging operators for chemometric data analysis
Published: Oct 6, 2013
Author(s): Haikel AlHichri, Yakoub Bazi, Naif Alajlan, Farid Melgani, Salim Malek, Ronald R. Yager
Journal: Journal of Chemometrics
This paper proposes a novel approach for the estimation of spectroscopic data by combining the predictions of an ensemble of estimators using the induced ordered weighted averaging (IOWA) fusion operators. For ensemble generation, we use Gaussian process regression (GPR) and extreme learning machine (ELM) estimators associated with different kernels. To render the model selection issue of ELM as efficiently as in the GPR Bayesian...
Read MoreLanthanide‐IMAC enrichment of carbohydrates and polyols
Published: Oct 6, 2013
Author(s): Dieter Schemeth, Matthias Rainer, Christoph B. Messner, Bernd M. Rode, Günther K. Bonn
Journal: Biomedical Chromatography
ABSTRACT In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4‐butandiole dimethacrylate using azo‐bis‐isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by...
Read MoreGlutamate and glutamine: a review of in vivo MRS in the human brain
Published: Oct 4, 2013
Author(s): Saadallah Ramadan, Alexander Lin, Peter Stanwell
Journal: NMR in Biomedicine
Our understanding of the roles that the amino acids glutamate (Glu) and glutamine (Gln) play in the mammalian central nervous system has increased rapidly in recent times. Many conditions are known to exhibit a disturbance in Glu–Gln equilibrium, and the exact relationships between these changed conditions and these amino acids are not fully understood. This has led to increased interest in Glu/Gln quantitation in the human brain in an...
Read MoreDifference spectra for the reduction of the feasible bands of response profiles of multivariate curve resolution: comparison of the feasible bands of difference spectra and ordinary data
Published: Oct 4, 2013
Author(s): Morteza Bahram, Elsie Beth‐Moushoul
Journal: Journal of Chemometrics
In multivariate curve resolution (MCR) methods, a bilinear decomposition of the experimental data matrix (D) is performed to estimate, for example, the concentration profiles (C) and the spectra (S) using the model equation, D = CST + E, where E is the error or noise matrix. The main limitation of all soft‐modeling methods is the fact that there is often no unique solution and sometimes a range of feasible solutions that fit the data equally well...
Read MoreQuantitative proton MR techniques for measuring fat
Published: Oct 3, 2013
Author(s): H. H. Hu, H. E. Kan
Journal: NMR in Biomedicine
Accurate, precise and reliable techniques for the quantification of body and organ fat distributions are important tools in physiology research. They are critically needed in studies of obesity and diseases involving excess fat accumulation. Proton MR methods address this need by providing an array of relaxometry‐based (T1, T2) and chemical shift‐based approaches. These techniques can generate informative visualizations of regional and whole‐body ...
Read MoreQuantitative proteomics characterization on the antitumor effects of isodeoxyelephantopin against nasopharyngeal carcinoma
Published: Oct 3, 2013
Author(s): Guang‐Rong Yan, Zilu Tan, Yang Wang, Man‐Li Xu, Guangchuang Yu, Yaolan Li, Qing‐Yu He
Journal: PROTEOMICS
Isolated from Elephantopus scaber L., a Chinese medicinal herb that is widely used to prevent and treat cancers in China, isodeoxyelephantopin (ESI) exerted antitumor effects on several cancer cells. However, its antitumor mechanism is still not clear. In this study, we found that ESI could induce G2/M arrest and subsequently stimulate cell apoptosis in dose‐ and time‐dependent manners. We used SILAC quantitative proteomics to identify...
Read MoreProteomics of C a CO 3 biomineral‐associated proteins: H ow to properly address their analysis
Published: Oct 3, 2013
Author(s): Benjamin Marie, Paula Ramos‐Silva, Frédéric Marin, Arul Marie
Journal: PROTEOMICS
In a recent editorial (Proc. Natl. Acad. Sci., 2013 110, E2144–E2146) and elsewhere, questions have been raised regarding the experimental practices in relation to the proteomic analysis of organic matrices associated to the biomineralized CaCO3 skeletons of metazoans such as molluscan shells and coral skeletons. Indeed, although the use of new high sensitivity MS technology potentially allows to identify a greater number of proteins, it is also...
Read MoreMultitarget fragment‐based design of novel inhibitors for AChE and SSAO/VAP‐1 enzymes
Published: Oct 3, 2013
Author(s): Sajjad Gharaghani, Taghi Khayamian, Malihe Ebrahimi
Journal: Journal of Chemometrics
In Alzheimer's disease, increased human semicarbazide‐sensitive amine oxidase/vascular adhesion protein‐1 (SSAO/VAP‐1) expression has been found to colocalize with abnormal amyloid deposition. In addition, inhibition of acetylcholinesterase in Alzheimer's disease treatment should allow the lowered levels of acetylcholine in the synapses a chance to induce a signal in the downstream nerve. We designed inhibitors that interacted with both...
Read MoreEffect of Al content on the structure of Al‐substituted goethite: a micro‐Raman spectroscopic study
Published: Oct 3, 2013
Author(s): Haibo Liu, Tianhu Chen, Xuehua Zou, Chengsong Qing, Ray L. Frost
Journal: Journal of Raman Spectroscopy
The characterization of X‐ray diffraction, X‐ray fluorescence, and field emission scanning electron microscope were used to confirm the successful preparation of Al‐substituted goethite with different Al content. The micro‐Raman spectroscopy was utilized to investigate the effect of Al content on the goethite lattice. The results show that all the feature bands of goethite shifted to high wavenumbers after the occurrence of Al...
Read MorePoint of care creatinine measurement for diagnosis of renal disease using a disposable microchip
Published: Oct 3, 2013
Author(s): Mónica Ávila, Arjan Floris, Steven Staal, Ángel Ríos, Jan Eijkel, Albert Berg
Journal: ELECTROPHORESIS
A point‐of‐care device for the determination of elevated creatinine levels in blood is reported. This device potentially offers a new and simple clinical regime for the determination of creatinine that will give huge time savings and removal of several steps of determination. The test employs a disposable prefilled microchip and the handheld Medimate Multireader®. By optimizing the analytical conditions it was found that the LOD of the...
Read MoreMicrofluidic chip capillary electrophoresis coupled with electrochemiluminescence for enantioseparation of racemic drugs using central composite design optimization
Published: Oct 3, 2013
Author(s): Wen Peng Guo, Zhi Bin Rong, Ying Hong Li, Ying Sing Fung, Guo Quan Gao, Zhi Ming Cai
Journal: ELECTROPHORESIS
Optimization based on central composite design (CCD) for enantioseparation of anisodamine (AN), atenolol (AT), and metoprolol (ME) in human urine was developed using a microfluidic chip‐CE device. Coupling the flexible and wide working range of microfluidic chip‐CE device to CCD for chiral separation of AN, AT, and ME in human urine, a total of 15 experiments is needed for the optimization procedure as compared to 75 experiments using the...
Read MoreDetermination of lipophilicity of γ‐butyrolactone derivatives with anticonvulsant and analgesic activity using micellar electrokinetic chromatography
Published: Oct 3, 2013
Author(s): Marek Bajda, Aleksandra Guła, Krzysztof Więckowski, Barbara Malawska
Journal: ELECTROPHORESIS
The lipophilicity of a library of 30 derivatives of dihydrofuran‐2(3H)‐one (γ‐butyrolactone) was determined by MEKC. Calibration curve prepared for ten reference drugs enabled to calculate partition coefficient (log P) for novel compounds. The results of MEKC analysis were compared with lipophilicity coefficients determined by RP‐TLC (RM0) and computational (Mlog P, Clog P) methods. Good correlation was observed between the results obtained by both experimental...
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