bluuebunny/crossref_metadata_2025_split huggingface dataset:
Borate‐Catalyzed Reactions of Hydrogen Peroxide: Kinetics and Mechanism of the Oxidation of Organic Sulfides by Peroxoborates
Authors: Davies D. Martin , Deary Michael E. , Quill Kieran , Smith Robert A. 
Published: April 2005

AbstractThe kinetics of the oxidation of substituted phenyl methyl sulfides by hydrogen peroxide in borate/boric acid buffers were investigated as a function of pH, total peroxide concentration, and total boron concentration. Second‐order rate constants at 25 °C for the reaction of methyl 4‐nitrophenyl sulfide and H2O2, monoperoxoborate, HOOB(OH)3−, or diperoxoborate, (HOO)2B(OH)2−, are 8.29×10−5, 1.51×10−2 and 1.06×10−2 M−1 s−1, respectively. Peroxoboric acid, HOOB(OH)2, is unreactive. The Hammett ρ values for the reactions of a range of substituted phenyl methyl sulfides and hydrogen peroxide, monoperoxoborate or diperoxoborate are −1.50±0.1, −0.65±0.07 and −0.48 (two points only), respectively. The ρ values for the peroxoborates are of significantly lower magnitude than expected from their reactivity compared to other peroxides. Nevertheless the negative ρ values indicate positive charge development on the sulfur atom in the transition state consistent with nucleophilic attack by the organic sulfides on the peroxoborates as with the other peroxides. The kinetic parameters, including the lack of reactivity of peroxoboric acid, are discussed in terms of the differences in the transition state of reactions involving peroxoboron species with respect to those of other peroxides.
Nanotubes from Isomeric Dibenzoylmethane Molecules
Authors: Zhao Liyun , Yang Wensheng , Luo Yi , Zhai Tianyou , Zhang Guangjin , Yao Jiannian 
Published: April 2005

AbstractOrganic nanotubes of various diameters were fabricated from the isomeric molecule dibenzoylmethane (DBM) by using an immersing technique with ordered porous alumina membrane as the template. The ratio of the enol isomers of DBM increased as the diameters of the nanotubes decreased. In addition, although almost no fluorescence could be detected for the DBM monomer, a striking enhancement in the fluorescence emission intensity of the nanotubes was observed as the diameters decreased. This is due to the increased ratio of the enol isomers.
Mitogen‐activated protein kinase expression and activation does not differentiate benign from malignant mesothelial cells
Authors: Vintman Lina , Nielsen Søren , Berner Aasmund , Reich Reuven , Davidson Ben 
Published: April 2005

AbstractBACKGROUNDIn vitro studies of malignant mesothelioma (MM) cells have suggested activation of mitogen‐activated protein kinase (MAPK) in response to asbestos exposure. The objective of this study was to investigate protein expression (level) and phosphorylation status (activity) of the extracellular‐regulated kinase (ERK), the c‐Jun amino‐terminal kinase (JNK), and the high‐osmolarity glycerol response kinase (p38) in vivo through the analysis of fresh frozen reactive mesothelium (RM) and MM specimens.METHODSMAPK levels were analyzed in 36 fresh‐frozen MM specimens (32 effusions, 4 biopsies) and in 14 RM specimens (all effusions) using immunoblotting with antibodies detecting the total (pan‐) and activated (phospho‐) fraction (p‐) of ERK, JNK, and p38. Values for pan‐MAPK and p‐MAPK expression and the p‐MAPK/pan‐MAPK ratio in MM and RM specimens were compared. Results were corroborated using immunocytochemistry for p‐ERK, p‐JNK, and p‐38 in selected specimens.RESULTSPan‐ERK, pan‐JNK, and pan‐p38 expression was found frequently in both MM specimens (35 of 36 specimens) and RM specimens (14 of 14 specimens) using immunoblotting, with comparable findings for activated p‐p38 (34 of 36 MM specimens, 13 of 14 RM specimens). Activation of p‐ERK (27 of 36 MM specimens, 10 of 14 RM specimens) and p‐JNK (25 of 36 MM specimens, 10 of 14 RM specimens) was less frequent. Pan‐ERK (P = 0.016), pan‐JNK (P = 0.004), pan‐p38 (P = 0.012), and p‐ERK (P = 0.02) expression levels were higher in MM specimens from female patients. Pan‐p38 expression levels also were higher in peritoneal MM specimens (P = 0.019). MM and RM showed similar MAPK expression, activation, and activation ratios (Mann–Whitney test; P > 0.05). Immunocytochemistry localized MAPK to MM and RM cells.CONCLUSIONSThe current results provided the first evidence of in vivo activation of MAPK in clinical MM and RM. The similar values in these two cell types suggest that MAPK may not be involved in the transformation of benign to malignant mesothelium, thus bringing into question the validity of using MAPKs as molecular therapeutic targets in patients with MM. Cancer 2005. © 2005 American Cancer Society.
Toll‐like receptor signaling inhibits structural development of the distal fetal mouse lung
Authors: Prince Lawrence S. , Dieperink Heather I. , Okoh Victor O. , Fierro‐Perez German A. , Lallone Roger L. 
Published: April 2005

AbstractWe tested the hypothesis that innate immune signaling in utero could disrupt the structural development of the fetal lung, contributing to the pathogenesis of bronchopulmonary dysplasia. Injection of Escherichia coli lipopolysaccharide (LPS) into the amniotic fluid of E15 BALB/cJ mice increased the luminal volume density of fetal mouse lungs at embryonic day (E) 17 and E18. LPS also increased luminal volume and decreased distal lung branching in fetal mouse lung explants. This effect required NF‐κB activation and functional Toll‐Like Receptor 4. Airway branching may require fibronectin‐dependent epithelial–mesenchymal interactions, representing a potential target for innate immune signaling. Anti‐fibronectin antibodies and LPS both blocked distal lung branching. By immunofluorescence, fibronectin localized to the clefts between newly formed airways but was restricted to peripheral mesenchymal cells in LPS‐exposed explants. These data suggest that LPS may alter the expression pattern of mesenchymal fibronectin, potentially disrupting epithelial–mesenchymal interactions and inhibiting distal airway branching and alveolarization. This mechanism may link innate immune signaling with defects in structural development of the fetal lung. Developmental Dynamics 233:553–561, 2005. © 2005 Wiley‐Liss, Inc.
Expression analysis of jagged genes in zebrafish embryos
Authors: Zecchin Elisabetta , Conigliaro Alice , Tiso Natascia , Argenton Francesco , Bortolussi Marino 
Published: April 2005

AbstractThe interaction of transmembrane Delta and Jagged/Serrate ligands with Notch receptors on neighboring cells is critically involved in cell specification during development. In zebrafish, the early expression of delta but not of jagged genes has been investigated in some detail. We have analyzed the sequence and embryonic expression pattern of the three zebrafish genes jagged1a, jagged1b, and jagged2. These genes, whose transcripts are detectable by in situ hybridization from early somitogenesis, are widely and dynamically expressed in embryos. Coexpression is limited, however, to the notochord and lens (jagged1a and jagged1b) and to the otic vesicle and pronephros (jagged1b and jagged2). Conversely, jagged1a and jagged2, both widely expressed in the central nervous system, are not coexpressed. jagged2 is also detected in the epidermis, newly formed somites, pharyngeal pouches, and pancreatic exocrine anlage and jagged1b in otic placodes and cell clusters close to the pancreatic islet. The similarities of the expression patterns of jagged and delta genes in zebrafish suggest that the Jagged and Delta ligands are functionally redundant or required in specific combinations in many differentiation processes. Developmental Dynamics 233:638–645, 2005. © 2005 Wiley‐Liss, Inc.
Mechanics and function in heart morphogenesis
Authors: Bartman Thomas , Hove Jay 
Published: April 2005

AbstractFor years, biomechanical engineers have studied the physical forces involved in morphogenesis of the heart. In a parallel stream of research, molecular and developmental biologists have sought to identify the molecular pathways responsible for embryonic heart development. Recently, several studies have shown that these two avenues of research should be integrated to explain how genes expressed in the heart regulate early heart function and affect physical morphogenetic steps, as well as to conversely show how early heart function affects the expression of genes required for morphogenesis. This review combines the perspectives of biomechanical engineering and developmental biology to lay out an integrated view of the role of mechanical forces in heart development. Developmental Dynamics 233:373–381, 2005. © 2005 Wiley‐Liss, Inc.
Dynamic balance between activation and repression regulates pre‐mRNA alternative splicing during heart development
Authors: Ladd Andrea N. , Stenberg Myrna G. , Swanson Maurice S. , Cooper Thomas A. 
Published: April 2005

AbstractCardiac troponin T (cTNT) exon 5 splicing is developmentally regulated such that it is included in embryonic but not adult heart. CUG‐BP and ETR‐3‐like factor (CELF) proteins promote exon inclusion, whereas polypyrimidine tract binding protein (PTB) and muscleblind‐like (MBNL) proteins repress inclusion. In this study, we addressed what happens to these regulatory proteins during heart development to shift the regulatory balance of cTNT alternative splicing. Using dominant‐negative proteins, we found that both CELF and PTB activities are required for appropriate splicing in cardiomyocytes. Two CELF proteins, CUG‐BP and ETR‐3, are nuclear and cytoplasmic in embryonic heart but are down‐regulated in adult heart concomitant with loss of exon inclusion. In contrast, PTB and MBNL1 are expressed throughout heart development. The patterns of cTNT splicing and expression of its regulatory factors are conserved between mouse and chicken. Thus, alternative splicing is determined by a balance between positive and negative regulation, and modulation of expression levels of auxiliary splicing regulators may drive developmental splicing changes. ETR‐3 and CUG‐BP proteins are also down‐regulated in other tissues during development, suggesting that CELF proteins play a broad role in developmental splicing regulation. Developmental Dynamics, 2005. © 2005 Wiley‐Liss, Inc.
Boundary formation in the Drosophila wing: Functional dissection of Capricious and Tartan
Authors: Milán Marco , Pérez Lidia , Cohen Stephen M. 
Published: April 2005

AbstractCells in multicellular organisms often do not intermingle freely with each other. Differential cell affinities contribute to organizing cells into different tissues. Drosophila limbs and rhombomeres of the vertebrate hindbrain are subdivided into compartments. Cells in adjacent compartments do not mix. The wing primordium is subdivided into dorsal (D) and ventral (V) compartments by the activity of the LIM‐homeodomain protein Apterous in D cells. The leucine‐rich repeats transmembrane proteins Capricious and Tartan have been shown to contribute to formation of the affinity boundary between dorsal and ventral compartments. Here, we have carried out a structure–function analysis of Capricious and Tartan. We present evidence that both the extracellular and intracellular domains are required for the establishment of a DV affinity boundary. Our data suggest that the extracellular domains of Capricious and Tartan may work as ligands of an unknown D cell surface protein. Their intracellular domains may be required to transduce a signal necessary for the establishment of the DV boundary. Developmental Dynamics 233:804–810, 2005. © 2005 Wiley‐Liss, Inc.
Bone marrow mesenchymal progenitor cells inhibit lymphocyte proliferation by activation of the programmed death 1 pathway
Authors: Augello Andrea , Tasso Roberta , Negrini Simone Maria , Amateis Andrea , Indiveri Francesco , Cancedda Ranieri , Pennesi Giuseppina 
Published: April 2005

AbstractBone marrow mesenchymal progenitor cells (BMSC) are used for regenerating tissues of mesodermal origin, as well as tissues of different embryological derivation. Experimental evidence shows that BMSC are able to suppress the activation of the immune response by mechanisms that are still not completely understood. Thus far, in vitro studies carried using human or mouse cells indicate that autologous or allogeneic BMSC strongly suppress proliferation of T lymphocytes, triggered by cellular stimuli, nonspecific mitogenic stimuli, or antigenic peptides. Using cell proliferation and blocking assays, we demonstrated that BMSC inhibited the activation of murine splenocytes, T, and B lymphocytes. Direct contact of BMSC and target cells in a cognate fashion determined the inhibition of cell proliferation via engagement of the inhibitory molecule programmed death 1 (PD‐1) to its ligands PD‐L1 and PD‐L2, leading the target cells to modulate the expression of different cytokine receptors and transduction molecules for cytokine signaling. Soluble factors present on supernatants of BMSC cultures were effective in suppressing proliferation of B cells to a mitogenic stimulus. Taken together, these results highlight the complexity of the role of BMSC in regulating the immune response, asserting the possibility of their therapeutic application in transplantation and autoimmune diseases.
Chemokines synergize in the recruitment of circulating neutrophils into inflamed tissue
Authors: Struyf Sofie , Gouwy Mieke , Dillen Chris , Proost Paul , Opdenakker Ghislain , Van Damme Jo 
Published: April 2005

AbstractThe innate immune response against micro‐organisms is mediated by phagocytes, attracted by chemokines and other G protein‐coupled receptor (GPCR) ligands. Originally, we observed increased neutrophil migration by the interaction of inflammatory CXC chemokines such as IL‐8/CXCL8 and granulocyte chemotactic protein (GCP)‐2/CXCL6 with regakine‐1, a CC chemokine constitutively present in plasma. We here demonstrate statistically significant synergy between regakine‐1 and the neutrophil attractants C5a or IL‐8/CXCL8 in inducing neutrophil shape change and migration under agarose. In addition, regakine‐1 attracted human bone marrow granulocytes and enhanced their chemotactic response to IL‐8/CXCL8 in a dose‐dependent manner. Thus, plasma chemokines may regulate the number of circulating leukocytes under homeostatic conditions and may facilitate extra recruitment of bone marrow neutrophils during inflammation. Indeed, in vivo, regakine‐1 provoked a mild neutrophilia in rabbits upon intravenous injection. We also observed that the CC chemokines regakine‐1 and monocyte chemotactic protein‐3/CCL7 as well as the CXC chemokine stromal cell‐derived factor‐1α/CXCL12 co‐operated with murine GCP‐2 after intraperitoneal co‐administration to increase neutrophil influx in mice. These data demonstrate that inducible and constitutive GPCR ligands synergize to enhance inflammation and facilitate a more effective immune response.
Split peripheral tolerance: CD40 ligation blocks tolerance induction for CD8 T cells but not for CD4 T cells in response to intestinal antigens
Authors: Chung Yeonseok , Ko Sung‐Youl , Ko Hyun‐Jeong , Kang Chang‐Yuil 
Published: April 2005

AbstractThe role of antigen‐presenting cells in the balance between immunity and tolerance to intestinal antigens remains poorly understood. In this study, we examined whether CD40 ligation affects the induction of CD4 and CD8 T cell tolerance in response to intestinal antigens. We show that an agonistic anti‐CD40 mAb treatment did not block the induction of OVA‐specific CD4 T cell tolerance, whereas this approach enabled strong priming of OVA‐specific cytotoxic T cells (CTL), preventing CTL tolerance to intestinal antigen. Such CTL priming was independent of CD4 T cell help but required B7 costimulation. Co‐administration of anti‐CD40 mAb increased the synthesis of IL‐2 and the expression of CD25 by CD8 T cells, but neither IL‐2 production nor CD25 expression by CD4 T cells was enhanced by anti‐CD40 mAb. However, neutralization of TGF‐β together with addition of agonistic anti‐CD40 mAb was able to reverse CD4 T cell tolerance. These findings suggest that the induction of tolerance versus immunity against intestinal antigens is determined by the status of the antigen‐presenting cells and that signals via CD40 differently regulate the outcome of CD4 and CD8 T cells in vivo.
Remediation of sites contaminated by oil refinery operations
Authors: Khaitan S. , Kalainesan S. , Erickson L.E. , Kulakow P. , Martin S. , Karthikeyan R. , Hutchinson S.L.L. , Davis L.C. , Illangasekare T.H. , Ng'oma Crispin 
Published: April 2005

AbstractThe oil industry contributes to contamination of groundwater and aquifers beneath refineries and oil terminals. The successful remediation of a contaminated site requires understanding both the hydrogeology and the nature and extent of contamination. The physical–chemical and biological mechanisms that govern contaminant release, transport and fate in soils, sediments, and associated fluid phases must be understood and quantified. In addition, understanding the flow and entrapment of nonaqueous phase liquids (NAPLs) including lighter‐than‐water nonaqueous phase liquids (LNAPLs) in contaminated aquifers is important for the effective design of the recovery and remediation schemes. Current remedial technologies and risk assessment techniques to remediate former oil refinery sites contaminated by NAPLs are described in this paper. Emphasis is given to the most promising remediation techniques such as pump‐and‐treat, on‐site bioremediation, phytoremediation, in situ soil washing, and thermal‐based technologies, such as steam‐enhanced extraction. Some enhancements to pump‐and‐treat techniques such as solvent flushing, polymer enhanced flushing, and air stripping are also discussed. Finally, important risk‐based cleanup criteria associated with contaminated soil at refineries are presented. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
Proton affinity ladder for uridine and analogs: influence of the hydroxyl group on the sugar ring conformation
Authors: Mezzache S. , Alves S. , Pepe C. , Quelquejeu M. , Fournier F. , Valery J.‐M. , Tabet J.‐C. 
Published: April 2005

AbstractA ladder of relative proton affinities (PA) for a series of modified uridines (e.g. araU, ddU, 5BrU, 5BrdU and 5IU) was established from competitive dissociations of proton‐bound heterodimers using Cooks and co‐workers' kinetic method. The studied heterodimers are constituted of a modified nucleoside and either an amino acid or a nucleoside with known PA value. These non‐covalent heterodimers were prepared under electrospray conditions to be selected and dissociated into the ion‐trap analyzer. These results allowed our PA ladder of uridine and deoxyuridine analogs substituted at the C‐5 position in the uracil ring to be extended. From this scale, it was showed that the substitution of hydrogen atom at the C‐2′ position in the sugar ring by a hydroxyl group involves a decrease of about 7 kJ mol−1. The experimental values for U, 5MeU, dU, 5MedU, ddU and araU are consistent with those obtained by DFT calculations (B3P86/6–31+G*//B3LYP/6–31G*). Several neutral and protonated conformations of these compounds were considered, in particular the ring conformation of furanose and the orientation of the base with respect to the sugar ring. These calculated results showed the influence of sugar substituent on the conformation of the neutral form of theses nucleosides. However, the most stable protonated structure is the same for all the studied nucleosides except for araU, where the position of the anti 2′‐OH group imposes a specific conformation. Copyright © 2005 John Wiley & Sons, Ltd.
Rheology and Drug Release Properties of Bioresorbable Hydrogels Prepared from Polylactide/Poly(ethylene glycol) Block Copolymers
Authors: Li Suming , El Ghzaoui Abdelslam , Dewinck Emilie 
Published: April 2005

AbstractRing‐opening polymerization of L(D)‐lactide was realized in the presence of poly(ethylene glycol) (PEG), yielding PLLA/PEG and PDLA/PEG block copolymers. Bioresorbable hydrogels were prepared from aqueous solutions containing both copolymers due to interactions and stereocomplexation between PLLA and PDLA blocks. The rheological properties of the hydrogels were investigated under various conditions by changing copolymer concentration, temperature, time and frequency. The hydrogels constitute a dynamic and evolutive system because of continuous formation/destruction of crosslinks and degradation. Drug release studies were performed on hydrogel systems containing bovine serum albumin (BSA). The release profiles appear almost constant with little burst effect. The release rate depends not only on gelation conditions such as time and temperature, but also on factors such as drug load, as well as molar mass and concentration of the copolymers.
Structural Evolution Process in Solvent‐Induced Crystallization Phenomenon of Syndiotactic Polystyrene
Authors: Tashiro Kohji 
Published: April 2005

AbstractStructural change has been traced in the solvent‐induced crystallization phenomenon of syndiotactic polystyrene through the time‐resolved measurements of infrared and Raman spectra and X‐ray diffraction. Immediately after the solvent is supplied to the glassy sample, the random coils start a micro‐Brownian motion and locally change to short regular helical segments after some induction time. These segments grow longer and gather together to form the crystal lattice. This crystallization occurs even at room temperature far below the original glass transition temperature (Tg = ca. 100°C), because Tg is shifted to ca. −90°C (in the case of chloroform) due to the plasticizing effect, as revealed by the temperature‐dependent infrared spectral measurement and the molecular dynamics calculation. The thus‐created sPS‐solvent complex was found to show a fast and reversible solvent exchange phenomenon between the originally‐existing solvent (toluene, for example) and the newly‐supplied different type of solvent (chloroform, for example). The time‐dependent measurement of wide‐angle and small‐angle X‐ray scatterings using a synchrotron radiation source revealed that the solvent exchange occurs with keeping both the columnar structure of the crystal and the stacked lamellar structure, and that the solvent exchange rate is in the order of chloroform > benzene > toluene, reflecting the difference in diffusion rate of solvent molecules and polymer‐solvent interaction.
Preparation and Characterization of Interpenetrating Polymer Hydrogels Based on Poly(acrylic acid) and Poly(vinyl alcohol)
Authors: Hernández Rebeca , López Daniel , Pérez Ernesto , Mijangos Carmen 
Published: April 2005

AbstractInterpenetrating polymer hydrogels (IPHs) of Poly (vinyl alcohol) (PVA) and Poly (acrylic acid) (PAAc) have been prepared by a sequential method: crosslinked PAAc chains were formed in aqueous solution by crosslinking copolymerization of acrylic acid and N, N′‐methylenebisacrylamide in the presence of PVA. The application of freezing‐thawing cycles (F‐T cycles) leads to the formation of a PVA hydrogel within the synthesized PAAc hydrogel. The swelling and the viscoelastic properties of the prepared IPHs were evaluated on the basis of the structural features obtained from solid state 13C‐NMR spectroscopy.
Effect of Solubility Parameter of Polymer‐Solvent Pair on Turbulent Drag Reduction
Authors: Kim Chul Am , Choi Hyoung Jin , Sung Jun Hee , Lee Hyung Min , Jhon Myung S. 
Published: April 2005

AbstractPolymer‐induced turbulent drag reduction by adding a minute amount of high‐molecular weight polyisobutylene (PIB) into two different organic solvents of n‐heptane and xylene was examined using a rotating disk system. The dependence of drag reduction (DR) efficiency on various factors such as polymer molecular weight, polymer concentration (C), and solvent quality was examined. Based on the linear relationship between C and C/DR for different molecular weights of PIB, a universal curve was able to characterize a particular polymer/solvent family, independent of the molecular weight of polymer.