bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 12‐aryl‐12H‐benzo[i][1,3]‐dioxolo[4,5‐b]xanthene‐6,11‐diones using silica sulfuric acid as an efficient and versatile catalyst under solvent‐free conditions
Authors: Wu Liqiang , Chao Shujun , Yan Fulin 
Published: September 2010

Abstract
Some novel 12‐aryl‐12H‐benzo[i][1,3]‐dioxolo[4,5‐b]xanthene‐6,11‐diones can be rapidly and efficiently synthesized in excellent yields by condensing a variety of aldehydes with 3,4‐methylenedioxyphenol and 2‐hydroxy‐1,4‐naphthoquinone in the presence of a catalytic amount of silica sulfuric acid under solvent‐free conditions. The simple experimental procedure, solvent‐free reaction conditions, utilization of an inexpensive and readily available catalyst, short period of conversion, and excellent yields are the advantages of the present method. Furthermore, the catalyst can be recycled and reused three times without significant loss of activity. The structures of the novel compounds are confirmed by IR, 1H‐NMR, 13C‐NMR, MS, and elemental analysis. J. Heterocyclic Chem., 2011.
The synthesis, X‐ray structure analysis, and photophysical characterization of 4‐[(E)‐2‐(4‐cyanophenyl)diazenyl]‐morpholine
Authors: Chin Taylor , Phipps Ashley , Fronczek Frank R. , Isovitsch Ralph 
Published: September 2010

Abstract
A novel triazene, 4‐[(E)‐2‐(4‐cyanophenyl)diazenyl]‐morpholine (1) was prepared via a diazonium ion coupling reaction between 4‐aminobenzonitrile and morpholine. The x‐ray structure of 1 was determined and evidenced π delocalization in the triazene subunit. The room temperature absorption spectrum of 1 in acetonitrile was dominated by an intense triazene‐centered π→π* transition at 325 nm. Compound 1 was observed to be luminescent, with an emission maximum at 434 nm in room temperature acetonitrile solution. The emission spectrum of 1 in propionitrile glass at 77K exhibited a narrowed emission band with a maximum at 449 nm. Broad emission from 400–700 nm with poorly resolved vibrational structure was observed from solid 1 at room temperature. J. Heterocyclic Chem., 2011.
Correlation of product ion profiles with molecular structures of androgenic and anabolic steroids in ESI MS/MS
Authors: Guan Fuyu , Uboh Cornelius E. , Soma Lawrence R. , You Youwen , Liu Ying , Li Xiaoqing 
Published: September 2010

AbstractAndrogenic and anabolic steroids (AASs) are a class of chemical substances closely related to testosterone in molecular structure. They can be abused to enhance performances in human and equine athletes, and are banned by the sports authorities. To assist with method development for doping analyses of AASs, investigations were conducted to correlate their product ion profiles with the molecular structures. Although very similar in chemical structure, AASs generated noticeably different product ion profiles from collision‐induced dissociation (CID). On the basis of both outlines of the product ion profiles and molecular structures, AASs studied were classified into six subclasses. In each subclass, the product ion profiles were identical or similar. However, the product ion profiles in one subclass were remarkably different from those in another. The classification reveals that the position and number of double bond(s) in conjugation with the 3‐carbonyl group in the molecular structure of an AAS have significant effects on product ion profile. The presence or absence of the 19‐methyl group in an AAS also has a remarkable influence on its product ion profile. A substitution in the A‐, B‐ or D‐ring of an AAS may cause a shift in mass value of the product ions. The correlation of product ion profiles with molecular structures of AASs has the implication that each AAS can be characterized by a combination of its [M + H]+ ion and product ion profile and as a result be identified with specificity. The classified product ion pattern may be useful in the identification of unknown AASs. Copyright © 2010 John Wiley & Sons, Ltd.
Competitive mass spectrometry binding assay for characterization of three binding sites of tubulin
Authors: Li Chien‐Ming , Lu Yan , Ahn Sunjoo , Narayanan Ramesh , Miller Duane D. , Dalton James T. 
Published: September 2010

AbstractTubulin is an attractive and established target for anticancer therapy. To date, the only method to determine the binding of inhibitor to tubulin has been competitive radioligand binding assays. We developed a non‐radioactive mass spectrometry (MS) binding assay to study the tubulin binding of colchicine, vinblastine and paclitaxel and to identify which of these three binding sites that a novel inhibitor binds. The method involves a very simple step of separating the unbound ligand from macromolecules using ultrafiltration. The unbound ligand in the filtrate can be accurately determined using highly sensitive and specific liquid chromatography tandem mass spectrometry (LC‐MS/MS) method using multiple reaction monitoring (MRM) mode. The assay was validated using podophyllotoxin, vincristine and docetaxel, drugs that compete to the colchicine‐, vinblastine‐ and paclitaxel‐binding sites in tubulin, respectively. This competitive binding assay allowed the reliable detection of interactions of these drugs with three binding sites on tubulin. This method was subsequently applied to determine the tubulin‐binding site of 4‐substituted methoxylbenzoyl‐aryl‐thiazoles (SMART‐H), a potent antitubulin agent developed in our laboratory. The results indicated that SMART‐H specifically and reversibly bound only to the colchicine‐binding site, but not to vinblastine‐ or paclitaxel sites. This new non‐radioligand binding method to determine the binding site on tubulin will function as a useful tool to study the binding sites of tubulin inhibitors. Copyright © 2010 John Wiley & Sons, Ltd.
Development of a fast LC–MS/MS method for quantification of rilmenidine in human serum: elucidation of fragmentation pathways by HRMS
Authors: Chytil Lukáš , Cvačka Josef , Marešová Věra , Štrauch Branislav , Widimský Jiří , Štícha Martin , Slanař Ondřej 
Published: September 2010

AbstractRilmenidine is an alpha 2 adrenoreceptor agonist used in the treatment of mild and moderate hypertension. In this study, a fast and accurate liquid chromatographic method with tandem mass spectrometric detection has been validated in order to assure quantification of rilmenidine in human serum. The fragmentation pathway of protonated rilmenidine was studied using high‐resolution mass spectrometry (HRMS). This study compared selectivity, linearity, accuracy, precision, extraction efficiency, matrix effect and sensitivity using common liquid–liquid extraction (LLE) and solid‐phase extraction (SPE) procedures. The limit of quantitation for both extraction techniques was 0.1 ng/ml. Several differences between the LLE and SPE have been observed in terms of linearity, accuracy, precision and matrix effect. Additionally, the advantages of SPE included less manual work load and increased recovery of rilmenidine in human serum to approximately 80% (LLE, 57%). The developed method involving SPE was found to be accurate (relative error (RE) < 5%), reproducible (relative standard deviation, RSD < 7%), robust and suitable for quantitative analysis of rilmenidine in serum samples obtained from patients under antihypertensive treatment. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of caffeic acid on haemoglobin‐mediated lipid and protein oxidation in washed cod mince during ice and frozen storage
Authors: Larsson Karin J , Undeland Ingrid K 
Published: September 2010

AbstractBACKGROUND: Little is known about the relation between haemoglobin (Hb)‐mediated lipid and protein oxidation in muscle foods and how these two reactions can be inhibited by naturally occurring antioxidants. This study was aimed at evaluating (1) lipid oxidation and protein oxidation induced by 20 µmol L−1 Hb during chilled and frozen storage of washed cod mince and (2) the efficiency of 10–1000 ppm (0.063–6.3 mmol L−1) caffeic acid in preventing these reactions.RESULTS: Addition of 20 µmol L−1 Hb increased peroxide value (PV), rancid odour, protein carbonylation, protein insolubilisation, redness loss and α‐tocopherol loss in ice‐stored washed cod mince. Since both lipid and protein oxidation developed at the same time, it was not possible to conclude which reaction initiated the other. All studied reactions were efficiently inhibited by ≥ 50 ppm caffeic acid, which could be a result of α‐tocopherol regeneration, general radical scavenging, reduced formation of oxidised Hb forms and/or conformational changes in Hb structure. During frozen storage the only clear effect of Hb was increased PV, and here caffeic acid was less efficient as an antioxidant.CONCLUSION: Hb‐induced lipid and protein oxidation occurred quickly in ice‐stored washed cod mince, and the two reactions could not be separated in time. During frozen storage, Hb caused only limited lipid oxidation. Caffeic acid (≥50 ppm) was an efficient antioxidant during ice storage. Copyright © 2010 Society of Chemical Industry
A systematic review of diagnostic procedures to detect midgut neuroendocrine tumors
Authors: Scarpa Marco , Prando Daniela , Pozza Anna , Esposti Elisa Degli , Castoro Carlo , Angriman Imerio 
Published: September 2010

AbstractThe aim of this work was to assess the diagnostic yield of some clinical diagnostic procedures utilized to establish a diagnosis of midgut neuroendocrine tumors (NETs). Medical databases published between 1982 and 2007 were analyzed. Seventeen observational studies, including 629 patients, met the inclusion criteria. Urinary 5‐HIAA is the first test to prescribe in patients with flushing or persistent, unexplained diarrhea. Abdominal CT scan and OctreoScan should be prescribed whenever NET is suspected. J. Surg. Oncol. 2010;102:877–888. © 2010 Wiley‐Liss, Inc.
An anisotropic Zienkiewicz–Zhu‐type error estimator for 3D applications
Authors: Farrell P. E. , Micheletti S. , Perotto S. 
Published: September 2010

AbstractWe extend the anisotropic Zienkiewicz–Zhu a posteriori error estimator of (Proceedings of the ENUMATH‐2009, Uppsala, Sweden, 29 June–3 July 2009) to three dimensions. Like the standard Zienkiewicz–Zhu estimator, the proposed estimator is designed to be independent of the problem at hand, is cheap to compute and easy to implement. In contrast to the standard Zienkiewicz–Zhu estimator, the elementwise counterpart of the proposed estimator explicitly takes into account the geometrical properties of the actual tetrahedron. Thus, in a wide variety of applications, the estimator is able to detect the anisotropic features exhibited by the solution of the governing equations. A metric‐based optimization procedure, rigorously addressed, drives the adaptation of the mesh. It is shown numerically to yield quasi‐optimal triangulations, dictating the accuracy‐vs‐number of elements behaviour. Despite being heuristic to some extent, in practice the overall anisotropic adaptation procedure turns out to be effective. Copyright © 2010 John Wiley & Sons, Ltd.
3D boundary recovery by constrained Delaunay tetrahedralization
Authors: Si H. , Gärtner K. 
Published: September 2010

AbstractThree‐dimensional boundary recovery is a fundamental problem in mesh generation. In this paper, we propose a practical algorithm for solving this problem. Our algorithm is based on the construction of a constrained Delaunay tetrahedralization (CDT) for a set of constraints (segments and facets). The algorithm adds additional points (so‐called Steiner points) on segments only. The Steiner points are chosen in such a way that the resulting subsegments are Delaunay and their lengths are not unnecessarily short. It is theoretically guaranteed that the facets can be recovered without using Steiner points. The complexity of this algorithm is analyzed. The proposed algorithm has been implemented. Its performance is reported through various application examples. Copyright © 2010 John Wiley & Sons, Ltd.
Weighted Smolyak algorithm for solution of stochastic differential equations on non‐uniform probability measures
Authors: Agarwal Nitin , Aluru N. R. 
Published: September 2010

AbstractThis paper deals with numerical solution of differential equations with random inputs, defined on bounded random domain with non‐uniform probability measures. Recently, there has been a growing interest in the stochastic collocation approach, which seeks to approximate the unknown stochastic solution using polynomial interpolation in the multi‐dimensional random domain. Existing approaches employ sparse grid interpolation based on the Smolyak algorithm, which leads to orders of magnitude reduction in the number of support nodes as compared with usual tensor product. However, such sparse grid interpolation approaches based on piecewise linear interpolation employ uniformly sampled nodes from the random domain and do not take into account the probability measures during the construction of the sparse grids. Such a construction based on uniform sparse grids may not be ideal, especially for highly skewed or localized probability measures. To this end, this work proposes a weighted Smolyak algorithm based on piecewise linear basis functions, which incorporates information regarding non‐uniform probability measures, during the construction of sparse grids. The basic idea is to construct piecewise linear univariate interpolation formulas, where the support nodes are specially chosen based on the marginal probability distribution. These weighted univariate interpolation formulas are then used to construct weighted sparse grid interpolants, using the standard Smolyak algorithm. This algorithm results in sparse grids with higher number of support nodes in regions of the random domain with higher probability density. Several numerical examples are presented to demonstrate that the proposed approach results in a more efficient algorithm, for the purpose of computation of moments of the stochastic solution, while maintaining the accuracy of the approximation of the solution. Copyright © 2010 John Wiley & Sons, Ltd.
Proteomic analysis of Pteris vittata fronds: Two arbuscular mycorrhizal fungi differentially modulate protein expression under arsenic contamination
Authors: Bona Elisa , Cattaneo Chiara , Cesaro Patrizia , Marsano Francesco , Lingua Guido , Cavaletto Maria , Berta Graziella 
Published: September 2010

AbstractArbuscular mycorrhizae (AM) are the most widespread mutualistic symbioses between the roots of most land plants and a phylum of soil fungi. AM are known to influence plant performance by improving mineral nutrition, protecting against pathogens and enhancing resistance or tolerance to biotic and abiotic stresses. The aim of this study was to investigate the frond proteome of the arsenic hyperaccumulator fern Pteris vittata in plants that had been inoculated with one of the two AM fungi (Glomus mosseae or Gigaspora margarita) with and without arsenic treatment. A protective role for AM fungi colonisation in the absence of arsenic was indicated by the down‐regulation of oxidative damage‐related proteins. Arsenic treatment of mycorrhizal ferns induced the differential expression of 130 leaf proteins with specific responses in G. mosseae‐ and Gi. margarita‐colonised plants. Up‐regulation of multiple forms of glyceraldehyde‐3‐phosphate dehydrogenase, phosphoglycerate kinase, and enolase, primarily in G. mosseae‐inoculated plants, suggests a central role for glycolytic enzymes in arsenic metabolism. Moreover, a putative arsenic transporter, PgPOR29, has been identified as an up‐regulated protein by arsenic treatment.
The proteome of lysosomes
Authors: Schröder Bernd A. , Wrocklage Christian , Hasilik Andrej , Saftig Paul 
Published: September 2010

AbstractLysosomes are organelles of eukaryotic cells that are critically involved in the degradation of macromolecules mainly delivered by endocytosis and autophagocytosis. Degradation is achieved by more than 60 hydrolases sequestered by a single phospholipid bilayer. The lysosomal membrane facilitates interaction and fusion with other compartments and harbours transport proteins catalysing the export of catabolites, thereby allowing their recycling. Lysosomal proteins have been addressed in various proteomic studies that are compared in this review regarding the source of material, the organelle/protein purification scheme, the proteomic methodology applied and the proteins identified. Distinguishing true constituents of an organelle from copurifying contaminants is a central issue in subcellular proteomics, with additional implications for lysosomes as being the site of degradation of many cellular and extracellular proteins. Although many of the lysosomal hydrolases were identified by classical biochemical approaches, the knowledge about the protein composition of the lysosomal membrane has remained fragmentary for a long time. Using proteomics many novel lysosomal candidate proteins have been discovered and it can be expected that their functional characterisation will help to understand functions of lysosomes at a molecular level that have been characterised only phenomenologically so far and to generally deepen our understanding of this indispensable organelle.
Identification of osteocyte‐selective proteins
Authors: Guo Dayong , Keightley Andrew , Guthrie Jill , Veno Patricia A. , Harris Stephen E. , Bonewald Lynda F. 
Published: September 2010

AbstractSince little is known regarding osteocytes, cells embedded within the mineralized bone matrix, a proteomics approach was used to discover proteins more highly expressed in osteocytes than in osteoblasts to determine osteocyte‐specific function. Two proteomic profiles obtained by two different proteomic approaches using total cell lysates from the osteocyte cell line MLO‐Y4 and the osteoblast cell line MC3T3 revealed unique differences. Three protein clusters, one related to glycolysis (Phosphoglycerate kinase 1, fructose‐bisphosphate aldolase A, hypoxia up‐regulated 1 [ORP150], triosephosphate isomerase), one to protein folding (Mitochondrial Stress‐70 protein, ORP150, Endoplasmin), and one to actin cytoskeleton regulation (Macrophage‐capping protein [CapG], destrin, forms of lamin A and vimentin) were identified. Higher protein expression of ORP‐150, Cap G, and destrin in MLO‐Y4 cells compared with MC3T3 cells was validated by gene expression, Western blotting, and in vivo expression. These proteins were shown to be selective in osteocytes in vivo using immuno‐staining of mouse ulnae. Destrin was most highly expressed in embedding osteoid osteocytes, GapG in embedded osteocytes, and ORP150 in deeply embedded osteocytes. In summary, the proteomic approach has yielded important information regarding molecular mechanisms used by osteocytes for embedding in matrix, the formation of dendritic processes, and protection within a hypoxic environment.
Two‐dimensional liquid chromatography system for online top‐down mass spectrometry
Authors: Tian Zhixin , Zhao Rui , Tolić Nikola , Moore Ronald J. , Stenoien David L. , Robinson Errol W. , Smith Richard D. , Paša‐Tolić Ljiljana 
Published: September 2010

AbstractAn online metal‐free weak cation exchange‐hydrophilic interaction LC/RPLC system has been developed for sensitive, high‐throughput top‐down MS. Here, we report results for analyzing PTMs of core histones, with a focus on histone H4, using this system. With just ∼24 μg on‐column of core histones (H4, H2B, H2A, and H3) purified from human fibroblasts, 41 H4 isoforms were identified, with the type and location of PTMs unambiguously mapped for 20 of these variants. Compared to corresponding offline studies reported previously, the online weak cation exchange‐hydrophilic interaction LC/RPLC platform offers significant improvement in sensitivity, with several orders of magnitude reduction in sample requirements and a reduction in the overall analysis time. To the best of our knowledge, this study represents the first online 2‐D LC‐MS/MS characterization of core histone mixture at the intact protein level.
Synthesis of diblock copolymers containing poly(N‐vinylcarbazole) by reversible addition‐fragmentation chain transfer polymerization
Authors: Hu Nan , Ji Wen‐Xi , Tong Yin‐Yin , Li Zi‐Chen , Chen Er‐Qiang 
Published: September 2010

AbstractThe reversible addition‐fragmentation chain transfer (RAFT) polymerization ofN‐vinylcarbazole (NVK) mediated by macromolecular xanthates was used to prepare three types of block copolymers containing poly(N‐vinylcarbazole) (PVK). Using a poly(ethylene glycol) monomethyl ether based xanthate (PEG‐X), the RAFT polymerization of NVK proceeded in a controlled way to afford a series of PEG‐b‐PVK with different PVK chain lengths. Successive RAFT polymerization of NVK and vinyl acetate (VAc) with a small molecule xanthate (X1) as the chain transfer agent was tested to prepare PVK‐b‐PVAc. Though both monomers can be homopolymerized in a controlled manner with this xanthate, only by polymerizing NVK first could give well‐defined block copolymers. The xanthate groups in the end of PVK could be removed by radical‐induced reduction using tributylstannane, and PVK‐b‐PVA was obtained by further hydrolysis of PVK‐b‐PVAc under basic conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Block length determination of the block copolymer mPEG‐b‐PS using MALDI‐TOF MS/MS
Authors: Crecelius Anna C. , Becer C.Remzi , Knop Katrin , Schubert Ulrich S. 
Published: September 2010

AbstractThe molar mass determination of block copolymers, in particular amphiphilic block copolymers, has been challenging with chromatographic techniques. Therefore, methoxy poly(ethylene glycol)‐b‐poly(styrene) (mPEG‐b‐PS) was synthesized by atom transfer radical polymerization (ATRP) and characterized in detail not only by conventional chromatographic techniques, such as size exclusion chromatography (SEC), but also by matrix‐assisted laser/desorption ionization tandem mass spectrometry (MALDI‐TOF MS/MS). As expected, different molar mass values were obtained in the SEC measurements depending on the calibration standards (either PEG or PS). In contrast, MALDI‐TOF MS/MS analysis allowed the molar mass determination of each block, by the scission of the weakest point between the PEG and PS block. Thus, fragments of the individual blocks could be obtained. The PEG block showed a depolymerization reaction, while for the PS block fragments were obtained in the monomeric, dimeric, and trimeric regions as a result of multiple chain scissions. The block length of PEG and PS could be calculated from the fragments recorded in the MALDI‐TOF MS/MS spectrum. Furthermore, the assignment of the substructures of the individual blocks acquired by MALDI‐TOF MS/MS was accomplished with the help of the fragments that were obtained from the corresponding homopolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
A new water‐soluble branched poly(ethylene imine) derivative having hydrolyzable imidazolidine moieties and its application to long‐lasting release of aldehyde
Authors: Morinaga Hisatoyo , Morikawa Hiroshi , Sudo Atsushi , Endo Takeshi 
Published: September 2010

AbstractA new water‐soluble poly(ethylene imine)‐derivative having imidazolidine moieties was developed. With using branched poly(ethylene imine) (BPEI) as a precursor, it was modified by Michael addition reaction of its primary amino group to an acrylate having poly(ethylene glycol) (PEG) chain. The modified BPEI was reacted with octanal to give the corresponding BPEI derivative having octanal‐derived imidazolidine moieties. The obtained polymer inherited the high hydrophilicity of the attached PEG chains to allow hydrolysis of the imidazolidine moieties under homogeneous conditions in aqueous media, leading to long‐lasting release of octanal. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010