bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of the c‐Met receptor complex in fibroblasts drives invasive cell behavior by signaling through transcription factor STAT3
Authors: Cramer Alexander , Kleiner Sandra , Westermann Martin , Meissner Anja , Lange Anika , Friedrich Karlheinz 
Published: April 2005

Abstractc‐Met is the receptor for hepatocyte growth factor/scatter factor (HGF/SF). It mediates multiple cellular responses in development and adult life, and c‐Met hyperactivity is associated with malignant transformation of cells and the acquisition of metastatic properties. Signal transducer and activator of transcription 3 (STAT3) has been shown to contribute to c‐Met‐mediated cell motility and is, thus, potentially involved in the control of invasive cell behavior. We have functionally reconstituted c‐Met‐dependent signal transduction in fibroblasts with the aim of studying Met‐driven cell invasiveness and the role of STAT3 in this phenomenon. Activation of the system was achieved by means of a hybrid receptor comprising the extracellular domain of the nerve growth factor (NGF) receptor TrkA, the cytoplasmic part of c‐Met and a C‐terminally fused blue fluorescent protein (BFP). In addition, a GFP‐tagged derivative of adaptor protein Gab1 was expressed. NGF‐stimulation of mouse fibroblasts expressing tagged versions of both Trk‐Met and Gab1 with NGF resulted in anchorage‐independent growth and enhanced invasiveness. By freeze‐fracture cytochemistry and electron microscopy, we were able to visualize the ligand‐induced formation of multivalent receptor complex assemblies within the cell membrane. NGF‐stimulation of the heterologous receptor system evoked activation of STAT3 as evidenced by tyrosine phosphorylation and the formation of STAT3 clusters at the cell membrane. siRNA‐mediated ablation of STAT3 expression resulted in a drastic reduction of c‐Met‐driven invasiveness, indicating an important role of STAT3 in the control of this particularly relevant property of transformed cells. © 2005 Wiley‐Liss, Inc.
Investigating the neuroprotective mechanism of action of a CDK5 inhibitor by phosphoproteome analysis
Authors: Gillardon Frank , Schrattenholz André , Sommer Bernd 
Published: April 2005

AbstractSmall molecule inhibitors of cyclin‐dependent kinase 5 (CDK5) protect neurons from cell death following various insults. To elucidate the cellular mechanism of action we investigated changes in protein phosphorylation in cultured rat cerebellar granule neurons after administration of the CDK5 inhibitor Indolinone A. By immunoblot analysis we detected enhanced phosphorylation of the extracellular signal‐regulated kinase1/2 (ERK1/2) and the Jun N‐terminal kinase (JNK) substrate c‐Jun. Co‐administration of U0126, an inhibitor of ERK1/2, or SP600125, an inhibitor of JNK, blocked phosphorylation of ERK1/2 or c‐Jun, but did not affect neuroprotection by the CDK5 inhibitor. By metal affinity chromatography, two‐dimensional (2D) gel electrophoresis, and MALDI‐TOF mass spectrometry we identified several phosphoproteins that accumulated in neurons treated with Indolinone A. Among them were proteins involved in neurotransmitter release, which is consistent with a physiological function of CDK5 in synaptic signaling. Moreover, we identified proteins acting in energy metabolism, protein folding, and oxidative stress response. Similar findings have been reported in yeast following inhibition of Pho85 kinase, which is homologous to mammalian CDK5 and acts in environmental stress signaling. These results suggest that inhibition of CDK5 activates stress responsive proteins that may protect neurons against subsequent injurious stimuli. © 2005 Wiley‐Liss, Inc.
Identification of transcripts specific for physiological gene activation by platelet‐derived growth factor (PDGF)‐B in intact brain tissue
Authors: Renner Oliver , Romero Lourdes , Carnero Amancio , Betsholtz Christer , Euler Monika 
Published: April 2005

AbstractPlatelet‐derived growth factor‐B (PDGF‐B) and its receptors play essential roles in the complex process of blood vessel maturation and they therefore constitute promising targets for therapeutic strategies against blood vessel‐related diseases. Additionally, they are involved in the autocrine stimulation of tumor cells and have been suggested to regulate tumor stroma fibroblasts. Our study aimed to identify genes that are regulated directly by PDGF‐B, or indirectly via the recruitment of perivascular cells, in the context of an intact tissue. We used a subtractive cloning technique to compare gene transcription in the brains of wild‐type (WT) mice and syngenic mice deficient of PDGF‐B leading to a defect in the recruitment of perivascular cells. The resulting 147 differentially expressed sequences contained early and late PDGF‐B target genes, and genes implicated in blood vessel maturation‐related pathways. Additionally, gene clusters for specific biological processes such as cell migration and intracellular transport were identified. Of eight randomly selected sequences, six were found expressed in cultured cells of mesenchymal origin, two of them inducible by exogenous PDGF‐BB. The collection of cDNA presented here provides insights into the changes provoked by the removal of one growth factor of a complete tissue and might be the basis for the identification of novel players in the complex process of blood vessel maturation. © 2005 Wiley‐Liss, Inc.
Spectroscopic characterization of the conformational states of the bis(trifluoromethanesulfonyl)imide anion (TFSI−)
Authors: Herstedt M. , Smirnov M. , Johansson P. , Chami M. , Grondin J. , Servant L. , Lassègues J. C. 
Published: April 2005

AbstractAb initio calculations were combined with infrared and Raman studies to distinguish spectroscopically the two conformers of the bis(trifluoromethanesulfonyl)imide anion, (TFSI−). Spectra of crystalline LiTFSI complexes with organic ligands, where the anion adopts a known conformational state, are presented to confirm the calculated spectra. Several regions are identified where either the infrared or the Raman spectra contain separate bands for the two conformers. The conformational equilibrium between the transoid and cisoid rotamers is then illustrated from the infrared spectra of solutions of LiTFSI in aprotic solvents. The transoid form is found to be more stable than the cisoid form by about 2.2 kJ mol−1, in good agreement with the present and earlier theoretical predictions. It is also shown that the IR and Raman spectral changes coming from conformational isomerism have to be carefully distinguished from those due to ionic interactions. Copyright © 2005 John Wiley & Sons, Ltd.
Soil erosion and runoff response to plant‐cover strips on semiarid slopes (SE Spain)
Authors: Raya A. Martínez , Zuazo V. H. Durán , Martínez J. R. Francia 
Published: April 2005

AbstractOver a four‐year period (1997–2000), soil loss and surface‐runoff patterns were monitored in hillside erosion plots with almond trees under different plant‐cover strips (thyme, barley and lentils) on the south flank of the Sierra Nevada (Lanjaron) in south‐eastern Spain. The erosion plots (580 m a.s.l.), located on a 35 per cent slope, were 144 m2 (24 m×6 m) in area. The plant‐cover strips, 3 m wide, ran across the slope. The most effective plant cover proved to be thyme, reducing soil loss by 97 per cent and runoff by 91 per cent, compared to bare soil. Barley reduced soil loss by 87 per cent and runoff by 59 per cent, compared to bare soil, while these percentages were 58 per cent and 18 per cent for lentils. Thyme proved 77 per cent more effective than barley and 93 per cent more effective than lentils in reducing soil loss; thyme was also 79 per cent more effective than barley and 90 per cent more than lentil in blocking runoff. The present study demonstrates the effectiveness of plant‐cover strips in controlling soil erosion and runoff on sloping agricultural land. Copyright © 2005 John Wiley & Sons, Ltd.
Model for end-stage liver disease (MELD) and allocation of donor livers.
Authors: Neuberger James , Thorburn Douglas 
Published: April 2005

Abstract

Background and aims: A consensus has been reached that liver donor allocation should be based primarily on liver disease severity and that waiting time should not be a major determining factor. Our aim was to assess the capability of the Model for End-Stage Liver Disease (MELD) score to correctly rank potential liver recipients according to their severity of liver disease and mortality risk on the OPTN liver waiting list. Methods: The MELD model predicts liver disease severity based on serum creatinine, serum total bilirubin, and INR and has been shown to be useful in predicting mortality in patients with compensated and decompensated cirrhosis. In this study, we prospectively applied the MELD score to estimate 3-month mortality to 3437 adult liver transplant candidates with chronic liver disease who were added to the OPTN waiting list at 2A or 2B status between November, 1999, and December, 2001. Results: In this study cohort with chronic liver disease, 412 (12%) died during the 3-month follow-up period. Waiting list mortality increased directly in proportion to the listing MELD score. Patients having a MELD score <9 experienced a 1.9% mortality, whereas patients having a MELD score > or =40 had a mortality rate of 71.3%. Using the c-statistic with 3-month mortality as the end point, the area under the receiver operating characteristic (ROC) curve for the MELD score was 0.83 compared with 0.76 for the Child-Turcotte-Pugh (CTP) score (P < 0.001). Conclusions: These data suggest that the MELD score is able to accurately predict 3-month mortality among patients with chronic liver disease on the liver waiting list and can be applied for allocation of donor livers.(Gastroenterology 2003;124:91–96.)
Prediction of Polymer Properties in LDPE Reactors
Authors: Wells Gary J. , Ray W. Harmon 
Published: April 2005

AbstractSummary: A new analysis tool is presented that uses the governing kinetic scheme to predict properties of low‐density polyethylene (LDPE) such as the detailed shape of the molecular weight distribution (MWD). A model that captures mixing details of autoclave reactor operation is used to provide a new criterion for the onset of MWD shouldering. Kinetic effects are shown to govern the existence of MWD shoulders in LDPE reactors, even when operation is far from perfectly‐mixed. MWD shoulders occur when the mean reaction environment has a relatively high radical concentration and has a high polymer content, and is at a low temperature. Such conditions maximize long chain formation by polymer transfer and combination‐termination, while limiting chain scission. For imperfectly‐mixed reactors, the blending of polymer‐distributions produced in different spatial locations has a small effect on the composite MWD. However, for adiabatic LDPE autoclaves, imperfect mixing broadens the stable range of mean reactor conditions, and thereby increases the possibility for MWD shouldering.Polymer MWD produced in an LDPE autoclave reactor by various kinetic mechanisms.magnified imagePolymer MWD produced in an LDPE autoclave reactor by various kinetic mechanisms.
Scale‐Free Power‐Law Distribution of Emulsion‐Polymerized Branched Polymers: Power Exponent of the Molecular Weight Distribution
Authors: Tobita Hidetaka 
Published: April 2005

AbstractSummary: The molecular weight distribution (MWD), formed in emulsion polymerization that involves the polymer transfer reaction during Interval II, may approach the power‐law distribution as polymerization proceeds. The power exponent, α, of the weight fraction distribution W(M) = M−α conforms to the relationship, α = 1/Pb, where Pb is the probability that the chain end is connected to a backbone chain. The MWD of emulsion‐polymerized polyethylene reported in literature agrees reasonably well with the relationship, W(M) = M−α with α = 1/Pb. This simple relationship could be used to estimate the Pb value from the MWD data, possibly leading to determining the polymer transfer constant under well‐designed experimental conditions. Because α > 1, the number‐average MW always approaches a finite value, but the weight‐ and higher order‐averages of MWD may continue to increase as the particle grows without limit depending on the magnitude of Pb. The power‐law distributions are self‐similar, possessing the nature of fractals and lacking a characteristic scale. The i‐th moment of the MWD for the present reaction system continues to increase without limit during Interval II for Pb ≥ 1/i.Molecular weight distribution of the emulsion‐polymerized polyethylene.magnified imageMolecular weight distribution of the emulsion‐polymerized polyethylene.
Synthesis of an oligosaccharide–polylysine dendrimer with reducing sugar terminals leading to acquired immunodeficiency syndrome vaccine preparation
Authors: Baigude Huricha , Katsuraya Kaname , Tokunaga Shinichi , Fujiwara Naohiko , Satoyama Masaya , Magome Tomohiro , Okuyama Kohsaku , Borjihan Gereltu , Uryu Toshiyuki 
Published: April 2005

AbstractA novel cellobiose–polylysine dendrimer with reducing sugar terminals was synthesized in which the reactive reducing end of a disaccharide cellobiose was directing outward. Hexa‐O‐benzyl‐4′‐(1‐carboxyethyl)‐cellobioside (HBCEC) was synthesized through the reaction of a 4′‐hydroxyl group of benzyl hexa‐O‐benzyl‐cellobioside with methyl 2‐chloropropionate, followed by the removal of the methyl ester group. HBCEC was reacted with polylysine dendrimer generation 3 (G3) to produce benzylated cellobiose–polylysine dendrimer G3. After debenzylation, a cellobiose–polylysine dendrimer G3 was obtained in which the reducing end of the cellobiose was the terminal group of the dendrimer. For the preparation of a dendrimer‐type acquired immunodeficiency syndrome vaccine, the cellobiose–polylysine dendrimer was reacted with a tripeptide (glycyl–prolyl–leucine) and a cyclic oligopeptide from the human immunodeficiency virus by reductive amination; this produced a tripeptide‐bound cellobiose–polylysine dendrimer and an insoluble compound, respectively. The structure analysis was carried out with NMR and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2195–2206, 2005
Simple determination of the herbicide napropamide in water and soil samples by room temperature phosphorescence
Authors: Salinas‐Castillo Alfonso , Fernández‐Sanchez Jorge Fernando , Segura‐Carretero Antonio , Fernández‐Gutiérrez Alberto 
Published: April 2005

AbstractA new, simple, rapid and selective phosphorimetric method for determining napropamide is proposed which demonstrates the applicability of heavy‐atom‐induced room‐temperature phosphorescence for analyzing pesticides in real samples. The phosphorescence signals are a consequence of intermolecular protection and are found exclusively with analytes in the presence of heavy atom salts. Sodium sulfite was used as an oxygen scavenger to minimize room‐temperature phosphorescence quenching. The determination was performed in 1 M potassium iodide and 6 mM sodium sulfite at 20 °C. The phosphorescence intensity was measured at 520 nm with excitation at 290 nm. Phosphorescence was easily developed, with a linear relation to concentration between 3.2 and 600.0 ng ml−1 and a detection limit of 3.2 ng ml−1. The method has been successfully applied to the analysis of napropamide in water and soil samples and an exhaustive interference study was also carried out to display the selectivity of the proposed method. Copyright © 2005 Society of Chemical Industry
Quantification of sifuvirtide in monkey plasma by an on‐line solid‐phase extraction procedure combined with liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Dai Shujia , Song Haifeng , Dou Guifang , Qian Xiaohong , Zhang Yangjun , Cai Yun , Liu Xiuwen , Tang Zhongming 
Published: April 2005

AbstractA simple, automated and rapid method has been developed for the determination of a novel antiviral peptide sifuvirtide in monkey plasma. Raw plasma samples were directly loaded onto an on‐line solid‐phase extraction (SPE) column, which removes the time‐consuming and laborious sample pretreatment. Following a timed valve‐switching event, the analyte was eluted on‐line to a reversed‐phase high‐performance liquid chromatography (RP‐HPLC) column and subsequently introduced into a linear ion trap mass spectrometer, LTQ‐MS, via an electrospray ionization (ESI) interface. The multiply charged peptides were specified and quantitatively analyzed using selective reaction monitoring (SRM). A highly pure four iodine‐sifuvirtide was synthesized using an optimized iodogen method and proved to be a suitable internal standard (IS). A single analysis run takes about 18 min. Validation of the method demonstrated that the linear calibration curves covered the range of 4.88–5000 ng/mL, and the correlation coefficients were above 0.9923. The limit of detection (LOD) with the signal‐to‐noise (S/N) ratio higher than 12 was calculated as 1.22 ng/mL. The intra‐ and inter‐batch precisions were less than 12.7% and 9.1%, and the mean accuracy ranged from −5.2% to 3.6%, respectively. Any carry‐over effect from the system was negligible. In a pharmacokinetic (PK) study of sifuvirtide after a single intravenous or subcutaneous dose in monkeys, the on‐line SPE‐LC/MS/MS system was successfully utilized to determine hundreds of samples with only one extraction column, which indicated the feasibility and the reliability of this method for application in preclinical and clinical PK studies of peptide drugs. Copyright © 2005 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization and electrospray ionization mass spectrometric study of 2,3‐dihydro‐1,4‐benzoxazepines
Authors: Kéki Sándor , Nagy Lajos , Deák György , Lévai Albert , Zsuga Miklós 
Published: April 2005

AbstractFragmentations of the protonated adduct ions [M+H]+ of seven 1,4‐benzoxazepine derivatives were studied using ‘post‐source decay’ matrix‐assisted laser desorption/ionization (PSD MALDI) and electrospray nozzle‐skimmer collisionally induced dissociation (ESI‐CID) mass spectrometric methods. It was found that both methods generated mainly product ions arising from the cross‐ring cleavages of the benzoxazepine ring. Similar product ions were generated under MALDI and ESI conditions; however, it was observed that the loss of the alkylene unit from the N‐substituted benzoxazepine, and the loss of a H2X molecule (where X = O or S), are more preferred under ESI conditions. Based on the experimental results a mechanism is also proposed for the fragmentation of the oxazepines studied. Copyright © 2005 John Wiley & Sons, Ltd.
Surface‐activated chemical ionization in the analysis of arginine in plasma samples
Authors: Cristoni Simone , Cantù Marco , Bernardi Luigi Rossi , Gerthoux Piermario , Gonella Elisabetta , Brambilla Maura , Cavalca Viviana , Zingaro Lorenzo , Guidugli Federico 
Published: April 2005

AbstractAlterations of arginine plasma levels are involved in several disorders of amino acid metabolism such as hurtnup, argininosuccinic aciduria, histidinemia, citrullinuria, and cystinuria. In this work a new liquid ionization source, surface‐activated chemical ionization (SACI), has been used to analyze arginine in human and rat plasma samples. Arginine was extracted and diluted ten times through protein precipitation. The diluted arginine samples were then analyzed using an ion‐exchange chromatographic column coupled with the SACI source and an ion trap analyzer using MS3 monitoring in order to increase the sensitivity and specificity of the analysis. The multiple‐point standard additions method was used to quantify the arginine. This method was employed to eliminate the matrix effect that affects all liquid ionization sources (APCI, ESI, SACI, etc.), and also does not require use of an internal standard. High‐quality results in terms of sensitivity, limit of detection, lower limit of quantitation, linearity and reproducibility, are demonstrated. Copyright © 2005 John Wiley & Sons, Ltd.
Ternary Indides REIrIn (RE = Ce, Sm, Gd–Ho), REIrIn2 (RE = La–Nd, Sm), and Yb2IrIn8
Authors: Zaremba Vasyl I. , Rodewald Ute Ch. , Pöttgen Rainer 
Published: April 2005

AbstractNew ternary indides REIrIn (RE = Ce, Sm, Gd–Ho), REIrIn2 (RE = La–Nd, Sm), and Yb2IrIn8 were synthesized from the elements in sealed tantalum tubes in a high‐frequency furnace. Single crystals were grown through special annealing procedures. Except PrIrIn2, all structures have been refined on the basis of single crystal X‐ray diffractometer data. The equiatomic indides RE IrIn (RE = Ce, Sm, Gd–Ho) crystallize with the hexagonal ZrNiAl type structure, space group $P{\bar 6}{\rm 2}m$. The iridium and indium atoms in REIrIn build up a three‐dimensional network in which the RE atoms fill distorted hexagonal channels. The indium atoms in the indium‐richer intermetallics REIrIn2 (RE = La–Nd, Sm) with orthorhombic MgCuAl2 type structure, space group Cmcm, form a three‐dimensional substructure of distorted corner‐sharing In4/4 tetrahedra. Together, these tetrahedra and the iridium atoms build up a three‐dimensional network in which the RE atoms fill distorted pentagonal channels. Yb2IrIn8 adopts the tetragonal Ho2CoGa8 structure, space group P4/mmm. Geometrical motifs of this structure are layers of YbIn12 cuboctahedra and stuffed IrIn8 cubes. The crystal chemistry and the Ir–In substructures of these intermetallics are discussed.
Die Kristallstruktur von Tl3Bi2I9: Eine komplexe Ausdünnungs‐ und Verzerrungsvariante des Perowskit‐Typs
Authors: Wosylus Aron , Schwarz Ulrich , Ruck Michael 
Published: April 2005

AbstractThe Crystal Structure of Tl3Bi2I9: A Complex Defect and Deformation Variant of the Perovskite Structure TypeBlack crystals of trithallium(I) enneaiododibismuthate(III) Tl3Bi2I9 were obtained by slow cooling of a melt with composition Tl : Bi : I = 3 : 2 : 9 from 800 K to ambient temperature. The compound is diamagnetic and decomposes peritectically at 619(2) K. X‐ray diffraction of single‐crystals revealed that Tl3Bi2I9 crystallizes in the monoclinic space group P21/n with lattice parameters a = 1438.9(1), b = 771.54(7), c = 2091.0(1) pm and β = 93.309(6)°, (Z = 4). The crystal structure can be described as a defect variant of the perovskite type (ABX3), where according to the formula Tl(Bi2/3□1/3)I3 the Bi atoms occupy only two thirds of the octahedral sites B. The vacancies are located in every third plane resulting in double layers of corner sharing [BiI6] polyhedra. By distortion and rotation of the [BiI6] polyhedra the coordination of the Tl atoms (cuboctahedral sites in the perovskite type, c.n. = 12) is reduced to bicapped trigonal prisms (c.n. = 8). The group‐subgroup relation between the Tl3Bi2I9 structure and the perovskite type results in a subgroup index of 144.