bluuebunny/crossref_metadata_2025_split huggingface dataset:
A small high‐irradiance laser ionization time‐of‐flight mass spectrometer
Authors: He Jian , Huang Rongfu , Yu Quan , Lin Yiming , Hang Wei , Huang Benli 
Published: January 2009

AbstractA small high‐irradiance laser ionization time‐of‐flight mass spectrometer (LI‐TOFMS) with orthogonal sample introduction was described. High irradiance of 6 × 1010 W/cm2 at 532 nm from a Nd : YAG laser was applied in the experiment to get a high ionization degree in plasma and to dissociate the interferential polyatomic ions. Meanwhile, the interferential multiply charged ions resulted by high‐irradiance were nearly eliminated in the spectrum by utilizing helium as the buffer gas in the ion source due to three‐body recombination, which resulted in a relatively clean background. Improved signal stability was obtained by automated step moving of the sample stage in short time intervals. By using two sets of Einzel lens in transport system, nearly uniform relative sensitivity coefficients (RSCs) were achieved for most of metal elements including light ions which were detected in extremely low sensitivity in previous hexapole transportation instrument. The resolving power reaches 2200, and the detection limits (DLs) are 10−6 g/g for metal elements in the steel standard. Copyright © 2009 John Wiley & Sons, Ltd.
Determination and quantification of astragalosides in Radix Astragali and its medicinal products using LC–MS
Authors: Zu Yuangang , Yan Mingming , Fu Yujie , Liu Wei , Zhang Lin , Gu Chengbo , Efferth Thomas 
Published: January 2009

AbstractIn the present study, a liquid chromatography–tandem mass spectrometry method was developed for the separation and simultaneous quantification of astragalosides I–IV in samples of Radix Astragali and a medicinal product thereof (Jinqi Jiangtang tablets). Chromatographic separation was achieved on an Agilent Eclipse XDB (ODS)‐C18 column with a mobile phase consisting of acetonitrile and 0.05% formic acid aqueous solution by use of an efficient 17‐min program. A triple quadrupole mass spectrometer was operated in positive ionization mode with multiple reaction monitoring for the detection of four astragalosides. The saponin ginsenoside Rg1 (similar structure to astralagosides) was used as an internal standard. All calibration curves showed excellent linear regressions (r2 ⪈ 0.9912) within the range of tested concentrations. The intra‐ and inter‐day variations were below 4.57% in terms of RSD. The recoveries were 94.38–103.53% with RSD of 1.39–3.58% for spiked Radix Astragali samples. The method was successfully used for the analysis of samples of Radix Astragali and Jinqi Jiangtang tablets. In conclusion, we have developed a rapid, efficient, and accurate LC–MS/MS method for the detection of astragalosides, which can be applied for quality control of Radix Astragali and related medicinal products.
Prediction of supercritical fluid chromatographic retention factors at different percents of organic modifiers in mobile phase
Authors: Fatemi Mohammad H. , Malekzadeh Hanieh , Shamseddin Hoda 
Published: January 2009

AbstractIn this work quantitative structure‐retention relationship models were developed to predict the solute retention factors in supercritical fluid chromatography (SFC) in various organic modifiers. Data set contains the retention data of 35 various organic compounds in 0, 2, 4 and 6% of methanol in mobile phase. The obtained 140 data points were divided into training, internal and external test sets which have 93, 23 and 24 retention data. The diversity validation test was performed on data the set to ensure that the structure of the training and/or test sets can represent those of the whole ones. Descriptors which were selected by stepwise multiple linear regression (MLR) methods are: the percent of organic modifier in mobile phase, salvation connectivity index chi‐2, salvation connectivity index chi‐5, H attached to heteroatom, the 2nd structural information content and polarity parameter. These descriptors were used as features in generation of linear and non‐linear models using MLR and artificial neural network (ANN) methods, respectively. The root mean square error of MLR model are 0.116, 0.138 and 0.260 for training, internal and external test sets, respectively, while these values are 0.036, 0.097 and 0.244 for ANN model, respectively. Comparison between these values and other statistical parameters obtained from these two models reveals the credibility of ANN in prediction of solute retention factors in SFC.
HPLC of fluoroquinolone antibacterials using chiral stationary phase based on enantiomeric (3,3′‐diphenyl‐1,1′‐binaphthyl)‐20‐crown‐6
Authors: Choi Hee Jung , Cho Hwan Sun , Han Sang Cheol , Hyun Myung Ho 
Published: January 2009

AbstractA residual silanol group‐protecting chiral stationary phase (CSP) based on optically active (3,3′‐diphenyl‐1,1′‐binaphthyl)‐20‐crown‐6 was successfully applied to the resolution of fluoroquinolone compounds including gemifloxacin mesylate. The chiral recognition ability of the residual silanol group‐protecting CSP was generally greater than that of the residual silanol group‐containing CSP. From these results, it was concluded that the simple protection of the residual silanol groups of the latter CSP with lipophilic n‐octyl groups can improve its chiral recognition ability for the resolution of racemic fluoroquinolone compounds. The chromatographic resolution behaviors were investigated as a function of the content and type of organic and acidic modifiers and the ammonium acetate concentration in aqueous mobile phase and the column temperature. Especially, the addition of ammonium acetate to the mobile phase was found to be a quite effective means of reducing the enantiomer retentions without sacrificing the chiral recognition efficiency of the CSP.
Novel compact laptop‐based image‐guidance system: Preliminary study
Authors: Nogueira Joao F. , Stamm Aldo C. , Lyra Macos 
Published: January 2009

AbstractObjectives:To describe a novel portable laptop‐based image‐guidance system and its preliminary navigational results.Methods:An optic‐based, specially developed navigational system and a life‐size endoscopic sinus anatomic model were used. The model was submitted to computer tomography (CT), and predefined anatomic landmarks were used to test the image‐guidance accuracy according to the real model.Results:All anatomic landmarks were identified by the image‐guidance system and all matched with endoscopic or eye views.Conclusions:This novel compact navigation device was shown to be fast and reliable. A larger series, involving more models, cadavers, and patients, with the evaluation of multiple anatomic points needs to be done before we can reliably determine the overall accuracy of this novel device. However, this new system is promising, and in the future it can be part of the armamentarium of otolaryngologists' personal equipment in order to perform low‐cost image‐guided surgeries in different places with the same equipment. Laryngoscope, 2009
Neuromonitoring of the external branch of the superior laryngeal nerve during minimally invasive thyroid surgery under local anesthesia: A prospective study of 10 patients
Authors: Inabnet William B. , Murry Thomas , Dhiman Shamly , Aviv Jonathan , Lifante Jean‐Christophe 
Published: January 2009

AbstractObjectives/Hypothesis:Avoiding alterations of the voice is a challenge in thyroid surgery. Identification and preservation of the external branch of the superior laryngeal nerve (EBSLN) is paramount for normal vocal function preservation after thyroidectomy. Conventional nerve monitoring requires a general anesthesia and placement of a special endotracheal tube equipped with electrodes to evoke the laryngeal nerves. This study aims to assess feasibility and efficacy of a novel technique of neuromonitoring of the EBSLN under local anesthesia during minimally invasive thyroidectomy.Study Design; Prospective Study:This study is a prospective trial to evaluate the efficacy of nerve monitoring of the EBSLN during minimally invasive thyroidectomy under local anesthesia. Patient self‐assessment of changes in perceived voice severity prior to and 3 weeks after surgery was assessed with the Voice Handicap Index‐10 (VHI‐10).Results:Thyroidectomy was successfully completed under local anesthesia in all cases. The recurrent laryngeal nerve(s) was identified and preserved in each patient as demonstrated by normal perioperative transnasal flexible laryngoscopy. A total of 15 EBSLNs were at risk, but only 8 EBSLNs (53%) were definitively identified. Neuromonitoring demonstrated preservation of the EBSLN in 100% of cases. The analysis of the results of the VHI‐10 questionnaire before and 3 weeks after surgery indicated no significant change in patients' perception of voice severity.Conclusion:Monitoring of the EBSLN during thyroidectomy under local anesthesia is a feasible alternative to conventional nerve monitoring under general anesthesia. This technique may be useful for the preservation of voice quality during a minimally invasive thyroidectomy under local anesthesia. Laryngoscope, 2009
Roles of vascular endothelial growth factor, Angiopoietin 1, and Angiopoietin 2 in nasal polyp
Authors: Park Seong Kook , Kim Hyeong In , Yang Young Il 
Published: January 2009

AbstractObjectives/Hypothesis:To determine the roles of vascular endothelial growth factor (VEGF), Angiopoietin (Ang)‐1, and Ang‐2 in nasal polyps (NPs) by assaying expression patterns and evaluating the effects of dexamethasone (DEX) on these factors in organ cultured NPs.Study Design:Prospective.Methods:Expression patterns of VEGF, Ang‐1, and Ang‐2 in NPs were compared with those in inferior turbinate mucosa samples. Tissue samples were analyzed using the enzyme‐linked immunosorbent assay (ELISA) and immunofluorescent staining methods. To determine the effects of DEX, NP tissues were cultured using an air‐liquid interface method. Cultures were maintained in the absence or presence of DEX (10 μM or 100 μM) for 24 hours, and tissue samples analyzed with ELISA.Results:VEGF and Ang‐1 levels were significantly higher, whereas the Ang‐2 level was significantly lower in NPs, compared to inferior turbinate mucosa (P < .05). In NPs, VEGF and Ang‐1 were detected in glandular epithelial, vascular endothelial, as well as stromal inflammatory cells, whereas Ang‐2 was detected only in stromal inflammatory cells. VEGF and Ang‐1 levels were significantly lower, while Ang‐2 levels were significantly higher in 100 μM DEX‐treated group than nontreated group (P < .01).Conclusions:Imbalance among VEGF, Ang 1, and Ang 2 may be important in the angiogenesis of NPs. Moreover, DEX can control the expression of these factors in NPs. We suggest that VEGF and Ang‐1 act as positive regulatory factors, and Ang‐2 functions as a negative regulatory factor of angiogenesis in NPs. Laryngoscope, 2009
Sonography‐assisted cutting needle biopsy in the head and neck for the diagnosis of lymphoma: Can it replace lymph node extirpation?
Authors: Pfeiffer Jens , Kayser Gian , Ridder Gerd J. 
Published: January 2009

AbstractObjectives:Malignant lymphoma frequently present with cervical lymph node enlargement. Before adequate therapy can be instituted, appropriate biopsy specimens must enable definite subclassification of the disease. While lymph node extirpation, traditionally considered the gold standard in the diagnostic evaluation of lymphoma, is invasive, diagnoses from fine needle aspiration cytology are often clinically insufficient on which to base treatment decisions. The aim of this study was to evaluate the diagnostic accuracy of cutting needle biopsy (CNB) in the management of patients in whom lymphoma was diagnosed or suspected in the head and neck.Study Design:Prospective quality assessment study in an academic tertiary care medical center.Methods:A systematic clinicopathological follow‐up study was performed over a period of 54 months, including the results of 347 CNBs in 160 patients with cervico‐facial masses. Ninety‐seven CNBs were done in 45 patients with malignant lymphoma as the final or the tentative diagnosis.Results:We experienced 100% success in obtaining high‐quality tissue cores. The target lymph node was correctly sampled in 41 of the 45 patients. Within these 41 patients, no false positive or false negative results were recorded. Full subclassification of the disease with prompt institution of therapy was possible in 92.3% of the lymphoma patients.Conclusions:CNB proved to be a sufficient alternative to open biopsy with excellent diagnostic yield and clinical usefulness. We recommend this procedure as the initial diagnostic step in patients with suspected lymphoma, either at presentation or at recurrence, and advocate its use in peripheral lymphadenopathy of the neck. Laryngoscope, 2009
The Effect of Clay Loading on the Morphology and Properties of Poly(styrene‐co‐butyl acrylate)/Clay Nanocomposites
Authors: Greesh Nagi , Hartmann Patrice C. , Sanderson Ronald D. 
Published: January 2009

AbstractThis paper investigates the effect of both the clay loading and the monomer feed rate on the morphology and properties of poly(styrene‐co‐butyl acrylate)‐clay nanocomposites prepared in emulsion polymerization. Analysis by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) of the nanocomposites prepared by batch polymerization showed that the polymer clay nanocomposites (PCNs) with 1–3 wt.‐% clay loading resulted in intercalated structures, while exfoliated structures were obtained at 10 wt.‐% clay loading. The polymerization was also carried out with semi‐batch polymerization. The morphology, thermal stability, and mechanical properties of nanocomposites obtained were found to be more strongly dependent on the clay/polymer ratio than the monomer feed rate.magnified image
Copolymer Sequence Distributions in Controlled Radical Polymerization
Authors: Zargar Amin , Schork F. Joseph 
Published: January 2009

AbstractAlthough simulations of polymerizations have been performed using population‐balance and method‐of‐moments techniques to determine the properties of copolymers, the method used most often to estimate copolymer composition distribution is based on probabilistic arguments and is not entirely compatible with the population balance approach. In this paper, a model based on the method of moments is presented that determines not only the molecular weight and copolymer composition characteristics, but also allows prediction of the copolymer distribution. The method is applied to controlled‐radical polymerization. Batch polymerizations are simulated to illustrate the effect of composition drift, and shot polymerizations are simulated to show the potential to produce copolymers with customized sequence distributions.magnified image
A new efficient explicit formulation for linear tetrahedral elements non‐sensitive to volumetric locking for infinitesimal elasticity and inelasticity
Authors: De Micheli P. O. , Mocellin K. 
Published: January 2009

AbstractWe introduce an innovative formulation for simple linear tetrahedral elements non‐sensitive to volumetric locking. Tetrahedral meshes enable to deal with high deformation by using efficient and robust adaptive meshers—while standard explicit formulations based on linear hexahedral elements with reduced integration and hourglassing stabilization cannot be coupled with efficient remeshing procedures. The principle of this anti‐locking modification is to impose the volumetric constraints at each node instead of at each integration point, as been done in the averaged nodal pressure formulation proposed by Bonet in 1998. However, the modification made here is material independent: the strain tensor is directly modified before any stress or pressure calculus. The formulation is extended to incompressible elasticity and von Mises incompressible isotropic inelasticity (elastic–visco‐plasticity). An infinitesimal strain formulation has been chosen in order to obtain a very simple and thus computational time saving algorithm. This choice can be easily justified taking into account the value of the critical time step in explicit simulations, especially for metal‐forming processes. Standard elastic and inelastic benchmarks issued from the literature validate qualitatively and quantitatively this promising formulation for quasi‐incompressible deformations cases. Copyright © 2009 John Wiley & Sons, Ltd.
ARGET ATRP of methyl methacrylate in the presence of nitrogen‐based ligands as reducing agents
Authors: Kwak Yungwan , Matyjaszewski Krzysztof 
Published: January 2009

AbstractBACKGROUND: Activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) employs reducing agents (e.g. ascorbic acid, tin(II) 2‐ethylhexanoate) to continuously reduce a deactivator Cu(II) to an activator Cu(I) species. In this work, copper‐mediated ARGET ATRP of methyl methacrylate (MMA) was studied in the presence of excess aliphatic nitrogen‐based ligands that served not only as ligands but also as reducing agents.RESULTS: Reduction of Cu(II) to Cu(I) by an excess amount of nitrogen‐based ligand was followed by UV‐visible spectroscopy. Well‐controlled poly(methyl methacrylate) (PMMA) with low polydispersity index (PDI) was prepared in the presence of Cu(II)Br2/excess ligand via ARGET ATRP. Chain extension of PMMA with MMA was successful, resulting in low‐PDI PMMA and demonstrating well‐maintained end‐group functionality.CONCLUSION: Well‐controlled PMMA with low PDI was prepared via ARGET ATRP in the presence of Cu(II) and nitrogen‐based ligands without any additional reducing agent. Aliphatic nitrogen‐based ligands for ATRP can serve as reducing agents as well as ligands. Copyright © 2009 Society of Chemical Industry
Unraveling theS‐nitrosoproteome: Tools and strategies
Authors: López‐Sánchez Laura M. , Muntané Jordi , de la Mata Manuel , Rodríguez‐Ariza Antonio 
Published: January 2009

AbstractOne of the major tasks to be accomplished in the postgenomic era is the characterization of PTMs in proteins. TheS‐nitrosation of protein thiols is a redox‐based PTM that modulating enzymatic activity, subcellular localization, complex formation, and degradation of proteins, largely contributes to the complexity of cellular proteomes. Although the detection ofS‐nitrosated proteins is problematical due to the lability ofS‐nitrosothiols, with the improvement of molecular tools an increasing range of proteins has been shown to undergoS‐nitrosation. We here review recent proteomic approaches for the systematic assessment of potential targets for proteinS‐nitrosation. The development of new analytical methods and strategies over the past several years now allows us to investigate the nitrosoproteome on a global scale.
A role for lipid droplets in inter‐membrane lipid traffic
Authors: Zehmer John K. , Huang Youguo , Peng Gong , Pu Jing , Anderson Richard G. W. , Liu Pingsheng 
Published: January 2009

AbstractAll cells have the capacity to accumulate neutral lipids and package them into lipid droplets. Recent proteomic analyses indicate that lipid droplets are not simple lipid storage depots, but rather complex organelles that have multiple cellular functions. One of these proposed functions is to distribute neutral lipids as well as phospholipids to various membrane‐bound organelles within the cell. Here, we summarize the lipid droplet‐associated membrane‐trafficking proteins and review the evidence that lipid droplets interact with endoplasmic reticulum, endosomes, peroxisomes, and mitochondria. Based on this evidence, we present a model for how lipid droplets can distribute lipids to specific membrane compartments.
Time‐dependent morphology development in segmented polyetherurea copolymers based on aromatic diisocyanates
Authors: Yilgor I. , Yilgor E. , Das S. , Wilkes G. L. 
Published: January 2009

AbstractTime‐dependent morphology development in segmented polyureas obtained by the stoichiometric reactions between amine terminated poly(tetramethylene oxide) (PTMO) and aromatic diisocyanates were investigated. Polyureas were prepared by reacting aminopropyl terminated PTMO oligomer (Mn = 1100 g/mol) and various aromatic diisocyanates, such as 1,4‐phenylene diisocyanate (PPDI), 1,3‐phenylene diisocyanate (MPDI), diphenylmethane diisocyanate (MDI), and tolylene diisocyanate (TDI). Time‐dependent FTIR studies were conducted on thin films cast onto KBr discs, which were annealed at 200 °C for 10 min in an air oven. After removing from the oven, samples were placed into the FTIR spectrometer at room temperature, where time‐dependent spectra were recorded until equilibrium was reached. Time‐dependent peak reorganization in 3500–3100 cm−1 (NH region), 1750–1450 cm−1 (CO region or amide I and amide II regions), and 1180–1020 cm−1 (COC) were monitored. Depending on the chemical structure and the symmetry of the diisocyanate, major differences were observed in the time needed to reach an equilibrium morphology in these homologous poly(ether urea) copolymers. Symmetric PPDI‐based polyurea reached equilibrium in about 1 h compared with its asymmetric MPDI‐based counterpart, which needed about 150 h. Microphase development of the MPDI urea was also characterized by AFM, which gave similar results. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 471–483, 2009
Simulation study of aggregate morphologies formed by ABC linear triblock copolymers in a selective solvent through the self‐consistent field theory
Authors: Ma Zengwei , Jiang Wei 
Published: January 2009

AbstractThe effect of the hydrophobic properties of blocks B and C on the aggregate morphologies formed by ABC linear triblock copolymers in selective solvent was studied through the self‐consistent field theory. Five typical micelles, such as core‐shell‐corona, hamburger‐like, segmented‐wormlike, were obtained by changing the hydrophobic properties of blocks B and C. The simulation results indicate that the shape and size of micelle are basically controlled by the hydrophobic degree of the middle block B, whereas the type of micelle is mainly determined by the hydrophobic degree of the end block C. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 484–492, 2009
Fabrication of carbon fibers with nanoporous morphologies from electrospun polyacrylonitrile/poly(L‐lactide) blends
Authors: Ji Liwen , Medford Andrew J. , Zhang Xiangwu 
Published: January 2009

AbstractPorous carbon nanofibers were prepared through electrospinning a blend solution of polyacrylonitrile and poly(L‐lactide), followed by carbonization at different temperatures and in different atmospheres. Structural features of these porous carbon nanofibers were characterized using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X‐ray powder diffraction, and Raman spectroscopy. Surface area and pore structure were evaluated using the nitrogen adsorption technique. It was found that carbon fibers prepared by this scalable and relatively economical method exhibited a porous surface morphology with high specific surface area and large pore volume. The fiber diameter, surface area, pore volume, bulky crystalline structure, and surface crystalline structure of these carbon nanofibers showed a strong dependence on the polymer precursor composition and carbonization condition. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 493–503, 2009