EarlyView Articles
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Simple and inexpensive instrument for deep‐UV Raman spectroscopy
Published: Oct 11, 2013
Author(s): M. A. Troyanova‐Wood, G. I. Petrov, V. V. Yakovlev
Journal: Journal of Raman Spectroscopy
Deep‐UV Raman spectroscopy is a powerful way to collect chemically specific information about complex samples. The availability of inexpensive and reliable light sources in the spectral region below 250 nm has been always considered a major bottleneck problem on the way of a widespread of this powerful spectroscopic technique. We report on the efficient fourth‐harmonic generation of a low‐power microchip Nd:YAG laser operating at 946 nm....
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Could marine aerosol contribute to deteriorate building materials from interior areas of lighthouses? An answer from the analytical chemistry point of view
Published: Oct 11, 2013
Author(s): Héctor Morillas, Maite Maguregui, Olivia Gómez‐Laserna, Josu Trebolazabala, Juan Manuel Madariaga
Journal: Journal of Raman Spectroscopy
In this work, a multianalytical methodology based on a combination of spectroscopic techniques such as Raman spectroscopy and micro energy dispersive X‐ray fluorescence spectroscopy, and soluble salt analysis by means of ion chromatography followed by a correlation analysis of these data was applied, in order to identify the nature of the deterioration compounds present in different building materials located on inner rooms from the...
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Particles small angle forward‐scattered light measurement based on photovoltaic cell microflow cytometer
Published: Oct 10, 2013
Author(s): Han‐Taw Chen, Lung‐Ming Fu, Hsing‐Hui Huang, Wei‐En Shu, Yao‐Nan Wang
Journal: ELECTROPHORESIS
A method is proposed for detecting microparticles in a microflow cytometer by means of small angle forward‐scattered light measurements. The proposed cytometer comprises a commercial photovoltaic cell, an adjustable power laser module, and a PDMS microfluidic chip. The detection performance of the proposed device is evaluated using particles with dimensions of 5, 8, 10, and 15 μm, respectively, given forward‐light scattering angles of 5...
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Joule heating effects on particle immobilization in insulator‐based dielectrophoretic devices
Published: Oct 10, 2013
Author(s): Roberto C. Gallo‐Villanueva, Michael B. Sano, Blanca H. Lapizco‐Encinas, Rafael V. Davalos
Journal: ELECTROPHORESIS
In this work, the temperature effects due to Joule heating obtained by application of a direct current electric potential were investigated for a microchannel with cylindrical insulating posts employed for insulator‐based dielectrophoresis. The conductivity of the suspending medium, the local electric field, and the gradient of the squared electric field, which directly affect the magnitude of the dielectrophoretic force exerted on...
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q ‐Space diffusion MRI (QSI) of the disease progression in the spinal cords of the Long Evans shaker: diffusion time and apparent anisotropy
Published: Oct 9, 2013
Author(s): Debbie Anaby, Ian D. Duncan, Chelsey M. Smith, Yoram Cohen
Journal: NMR in Biomedicine
q‐Space diffusion MRI (QSI) was used to study the spinal cords of Long Evans shaker (les) rats, a model of dysmyelination, and their age‐matched controls at different maturation stages. Diffusion was measured parallel and perpendicular to the fibers of the spinal cords of the two groups and at different diffusion times. The results showed that QSI is able to detect the dysmyelination process that occurs in this model in the different stages of the...
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Liquid chromatographic resolution of racemic rasagiline and its analogues on a chiral stationary phase based on (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid
Published: Oct 9, 2013
Author(s): Kyung Mi Tak, Eun Ju Park, Myung Ho Hyun
Journal: Journal of Separation Science
A liquid chromatographic chiral stationary phase based on (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid was applied to the resolution of 15 analytes, including racemic rasagiline, a chiral drug for the treatment of Parkinson's disease, and its analogues. The composition of mobile phase was optimized to be ethanol/acetonitrile/acetic acid/triethylamine (80:20:0.2:0.3, v/v/v/v) by evaluating the chromatographic results for the resolution...
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Capillary liquid chromatography fraction collection and postcolumn reaction using segmented flow microfluidics
Published: Oct 9, 2013
Author(s): Jing Nie, Robert T. Kennedy
Journal: Journal of Separation Science
A challenge for capillary LC (cLC) is fraction collection and the manipulation of fractions from microscale columns. An emerging approach is the use of segmented flow or droplet technology to perform such tasks. In this work, a fraction collection and postcolumn reaction system based on segmented flow was developed for the gradient cLC of proteins. In the system, column effluent and immiscible oil are pumped into separate arms of a tee...
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HPLC analysis of synthetic polymers on short monolithic columns
Published: Oct 9, 2013
Author(s): Elena Maksimova, Evgenia Vlakh, Ekaterina Sinitsyna, Tatiana Tennikova
Journal: Journal of Separation Science
Ultrashort monolithic columns (disks) were thoroughly studied as efficient stationary phases for precipitation–dissolution chromatography of synthetic polymers. Gradient elution mode was applied in all chromatographic runs. The mixtures of different flexible chain homopolymers, such as polystyrenes, poly(methyl methacrylates), and poly(tert‐butylmethacrylates) were separated according to their molecular weights on both commercial...
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Simultaneous isocratic separation of phenolic acids and flavonoids using micellar liquid chromatography
Published: Oct 9, 2013
Author(s): Mohammad Reza Hadjmohammadi, S. Saman S. J. Nazari
Journal: Journal of Separation Science
The simultaneous isocratic separation of a mixture of five phenolic acids and four flavonoids (two important groups of natural polyphenolic compounds with very different polarities) was investigated in three different RPLC modes using a hydro‐organic mobile phase, and mobile phases containing SDS at concentrations below and above the critical micellar concentration (submicellar LC and micellar LC (MLC), respectively). In the hydro‐organic...
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Determination of 48 fragrance allergens in toys using GC with ion trap MS / MS
Published: Oct 9, 2013
Author(s): Qing Lv, Qing Zhang, Wentao Li, Haiyu Li, Pi Li, Qiang Ma, Xianshuang Meng, Meiling Qi, Hua Bai
Journal: Journal of Separation Science
This paper presents a method for the simultaneous determination of 48 fragrance allergens in four types of toys (plastic toys, play clays, plush toys, and paper toys) based on GC with ion trap MS/MS. Compared with single‐stage MS, MS/MS is superior in terms of the qualification and quantification of a large range of compounds in complicated matrices. Procedures for extraction and purification were optimized for each toy type. The method...
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Analysis of the traditional medicine Y i G an S an by the fragmentation patterns of cadambine indole alkaloids using HPLC coupled with high‐resolution MS
Published: Oct 9, 2013
Author(s): YaNan Gai, Han Chen, ChunYong Wu, Feng Feng, YiXiang Wang, WenYuan Liu, SuiLou Wang
Journal: Journal of Separation Science
YiGan San (YGS) has long been used in traditional Japanese and Chinese folk medicine and serves as a potent and novel therapeutic agent to treat Alzheimer's disease. In the present study, a rapid and sensitive method based on HPLC coupled with diode‐array detection and quadrupole TOF MS (Q‐TOF‐MS) was designed to reveal the chemical constituents of YGS. Thirty‐six compounds were identified and assigned in YGS, including 14 alkaloids, nine...
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Magnetic separation of heavy metal ions and evaluation based on surface‐enhanced Raman spectroscopy: Copper(II) ions as a case study
Published: Oct 9, 2013
Author(s): Xue Yan, Xue‐Jiao Zhang, Ya‐Xian Yuan, San‐Yang Han, Min‐Min Xu, Ren'ao Gu, Jian‐Lin Yao
Journal: Journal of Separation Science
A new approach was developed for the magnetic separation of copper(II) ions with easy operation and high efficiency. p‐Mercaptobenzoic acid served as the modified tag of Fe2O3@Au nanoparticles both for the chelation ligand and Raman reporter. Through the chelation between the copper(II) ions and carboxyl groups on the gold shell, the Fe2O3@Au nanoparticles aggregated to form networks that were enriched and separated from the solution by a magnet. A significant ...
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Proteomic analysis reveals important role of 14‐3‐3σ in anoikis resistance of cholangiocarcinoma cells
Published: Oct 9, 2013
Author(s): Amnart Khongmanee, Kriengsak Lirdprapamongkol, Phanthakarn Tit‐oon, Daranee Chokchaichamnankit, Jisnuson Svasti, Chantragan Srisomsap
Journal: PROTEOMICS
Cholangiocarcinoma (CCA), a high‐prevalence cancer in Thailand, is highly metastatic and has high mortality rates. Anoikis resistance or the ability of cells to survive after detachment from extracellular matrix is a necessary property of metastatic cancer. Here, we report differential protein expression of an anoikis‐resistant CCA cell line culture, under attachment conditions compared to nonattachment conditions, studied using 2DE...
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Evaluation of protein extraction protocols for 2 DE in marine ecotoxicoproteomics
Published: Oct 9, 2013
Author(s): Huifeng Wu, Chenglong Ji, Lei Wei, Jianmin Zhao
Journal: PROTEOMICS
In ecotoxicoproteomics, an accurate and reproducible extraction of proteins is a critical step for 2DE analysis and further protein identification using MS. The criteria for the assessment of protein extraction quality include protein yield, protein spots resolved in a 2DE gel, matched protein spots in replicate gels, reproducibility, and compatibility with MS. In this work, we evaluated three protein extraction systems, straightforward...
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N ‐Terminal methylation of proteasome subunit R pt1 in yeast
Published: Oct 9, 2013
Author(s): Yayoi Kimura, Yoichi Kurata, Akiyo Ishikawa, Akiko Okayama, Masahiro Kamita, Hisashi Hirano
Journal: PROTEOMICS
The 26S proteasome is a multicatalytic protease complex that degrades ubiquitinated proteins in eukaryotic cells. It consists of a proteolytic core (the 20S proteasome) as well as regulatory particles, which contain six ATPase (Rpt) subunits involved in unfolding and translocation of substrates to the catalytic chamber of the 20S proteasome. In this study, we used MS to analyze the N‐terminal modifications of the yeast Rpt1 subunit, which...
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High throughput screening of disulfide‐containing proteins in a complex mixture
Published: Oct 9, 2013
Author(s): Dong S. Zhao, Zachery R. Gregorich, Ying Ge
Journal: PROTEOMICS
The formation of disulfide bonds between cysteine residues is crucial for the stabilization of native protein structures and, thus, determination of disulfide linkages is an important facet of protein structural characterization. Nonetheless, the identification of disulfide bond linkages remains a significant analytical challenge, particularly in large proteins with complex disulfide patterns. Herein, we have developed a new LC/MS...
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Amino‐functionalized macroporous silica for efficient tryptic digestion in acidic solutions
Published: Oct 9, 2013
Author(s): Jinrui Gan, Kun Qian, Jingjing Wan, Liang Qiao, Weichao Guo, Pengyuan Yang, Hubert H. Girault, Baohong Liu
Journal: PROTEOMICS
Amino‐functionalized macroporous silica foam (NH2‐MOSF) has been developed as a host reactor to realize highly efficient proteolysis in acidic solutions where normal tryptic reactions cannot occur. The digestion protocol consists simply of adding the functionalized NH2‐MOSF into the protein and trypsin solutions without altering the bulk pH or preloading the enzymes on the materials. With this protocol, digestion of sample fractions from LC can be...
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Surface proteomic analysis of differentiated versus stem‐like osteosarcoma human cells
Published: Oct 9, 2013
Author(s): Marica Gemei, Claudia Corbo, Francesca D'Alessio, Rosa Di Noto, Renza Vento, Luigi Del Vecchio
Journal: PROTEOMICS
Cancer stem cell characterization represents a breakthrough in cancer research. Despite evidence showing the existence and the role of cancer stem cells in osteosarcoma (OS) onset and progression, little is known about their specific surface phenotype. To address this issue, we carried out a cytometric analysis with an antibody‐array comprising 245 membrane proteins comparing the stem and differentiated OS cells. As experimental model, we...
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Supervised principal components: a new method for multivariate spectral analysis
Published: Oct 9, 2013
Author(s): Jun Bin, Fang‐Fang Ai, Nian Liu, Zhi‐Min Zhang, Yi‐Zeng Liang, Ru‐Xin Shu, Kai Yang
Journal: Journal of Chemometrics
The supervised principal components (SPC) method was proposed by Bair and Tibshirani for statistics regression problems where the number of variables greatly exceeds the number of samples. This case is extremely common in multivariate spectral analysis. The objective of this research is to apply SPC to near‐infrared and Raman spectral calibration. SPC is similar to traditional principal components analysis except that it selects the most...
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Factors influencing the electrokinetic injection of oligonucleotides in capillary gel electrophoresis when using laser‐induced fluorescence detection
Published: Oct 9, 2013
Author(s): Buyun Chen, Guanhua Chen, Michael G. Bartlett
Journal: Biomedical Chromatography
ABSTRACT Capillary gel electrophoresis (CGE) is a powerful tool for the analysis of oligonucleotides owing to its extraordinary resolving power. However, the only feasible injection mode for CGE, electrokinetic injection, can cause bias of the injected amount and thus reproducibility issues for CGE methods. Although the source of the bias in electrokinetic injection for analysis of small molecules by capillary zone electrophoresis...
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