bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of supported vanadium catalyst on ethylene polymerization reactions
Authors: Ghosh Sutapa 
Published: September 2007

AbstractBACKGROUND: In the research area of homogeneous Ziegler–Natta olefin polymerization, classic vanadium catalyst systems have shown a number of favourable performances. These catalysts are useful for (i) the preparation of high molecular weight polymers with narrow molecular weight distributions, (ii) the preparation of ethylene/R‐olefin copolymers with high R‐olefin incorporation and (iii) the preparation of syndiotactic polypropylenes. In view of the above merits of vanadium‐based catalysts for polymerization reactions, the development of well‐defined single‐site vanadium catalysts for polymerization reactions is presently an extremely important industrial goal. The main aim of this work was the synthesis and characterization of a heterogeneous low‐coordinate non‐metallocene (phenyl)imido vanadium catalyst, V(NAr)Cl3, and its utility for ethylene polymerization.RESULTS: Imido vanadium complex V(NAr)Cl3 was synthesized and immobilized onto a series of inorganic supports: SiO2, methylaluminoxane (MAO)‐modified SiO2 (4.5 and 23 wt% Al/SiO2), SiO2 Al2O3, MgCl2, MCM‐41 and MgO. Metal contents on the supported catalysts determined by X‐ray fluorescence spectroscopy remained between 0.050 and 0.100 mmol V g−1 support. Thermal stability of the catalysts was determined by differential scanning calorimetry (DSC). Characterization of polyethylene was done by gel permeation chromatography and DSC. All catalyst systems were found to be active in ethylene polymerization in the presence of MAO or triisobutylaluminium/MAO mixture (Al/V = 1000). Catalyst activity was found to depend on the support nature, being between 7.5 and 80.0 kg PE (mol V)−1 h−1. Finally, all catalyst systems were found to be reusable for up to three cycles.CONCLUSION: Best results were observed in the case of silica as support. Acid or basic supports afforded less active systems. In situ immobilization led to higher catalyst activity. The resulting polyethylenes in all experiments had ultrahigh molecular weight. Finally, this work explains the synthesis and characterization of reusable supported novel vanadium catalysts, which are useful in the synthesis of very high molecular weight ethylene polymers. Copyright © 2007 Society of Chemical Industry
Polyurethane networks from polyols obtained by hydroformylation of soybean oil
Authors: Petrović Zoran S , Guo Andrew , Javni Ivan , Cvetković Ivana , Hong Doo Pyo 
Published: September 2007

AbstractBACKGROUND: Vegetable oil‐based polyols are a new class of renewable materials. The structure of oil‐based polyols is very different from that of petrochemical polyols, and it is closely related to the structure of oils. The objective of this work was to analyze the structural heterogeneity of soy‐based polyols and its effect on the properties of polyols and polyurethanes.RESULTS: A series of polyols with a range of hydroxyl numbers were prepared by hydroformylation and partial esterification of hydroxyls with formic acid. Polyols were reacted with diphenylmethane diisocyanate to obtain polyurethanes of different crosslinking density. Gelation was simulated using the Monte Carlo method with a calculated distribution of functionalities for each polyol.CONCLUSIONS: Most polyols are powerful crosslinkers since weight average functionality varied from 5 to 2.5 resulting in gel points from 53 to 83% conversion. Heterogeneity of polyols had a negative effect on mechanical properties of rubbery polyurethanes and this should be taken in account when designing polyols for flexible applications. This effect was not pronounced in glassy polyurethanes. Copyright © 2007 Society of Chemical Industry
Morphological characterization of attapulgite/poly(methyl methacrylate) particles prepared by soapless emulsion polymerization
Authors: Liu Yushan , Liu Peng , Su Zhixing 
Published: September 2007

AbstractBACKGROUND: The synthesis of core–shell inorganic/polymer nanocomposites, in which the polymer shell determines the chemical properties and the interaction with the environment, whereas their physical properties are governed by both the size and shape of the inorganic core and the surrounding organic layer, is an area of increasing research activity.RESULTS: Core–shell and bead–string shaped attapulgite/poly(methyl methacrylate) (ATP/PMMA) nanocomposite particles were prepared by soapless emulsion polymerization in an aqueous suspension of attapulgite organically modified with cetyltrimethylammonium bromide.CONCLUSION: Transmission electron microscopy analysis results showed that the amounts of the monomer added had no influence on the morphologies of the ATP/PMMA particles. The morphologies only depended on the length/diameter ratio of the attapulgite fibrillar single crystal used. Long ATP needles formed the bead–string structure while short ATP needles formed the core–shell structure. Copyright © 2007 Society of Chemical Industry
Correlation of residual stress and adhesion on copper by the effect of chemical structure of polyimides for copper‐clad laminates
Authors: Jang Wonbong , Seo Minbum , Seo Jongchul , Park Sunggook , Han Haksoo 
Published: September 2007

AbstractBACKROUND: Polyimide films coated on copper are a potential new substrate for fabricating printed circuit boards; however, adhesion between the copper and polyimide films is often poor. The relations between residual stress and adhesion strength according to the development of molecular orientation of polyimide films with different chemical backbone structure coated on copper were studied.RESULTS: The effect of chemical structures on properties including the residual stress and the adhesion strength were widely investigated for four different polyimides. Diamine 4,4′‐oxydianiline (ODA) and dianhydrides 1,2,4,5‐benzenetetracarboxylic dianhydride (PMDA), 4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 4,4′‐oxydiphthalic anhydride (ODPA) and 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) were used to synthesize polyimide. In an attempt to quantify the interaction of thermal mismatch with the polyimide films depending on various structures, residual stress experiments between polyimide film and CuSi wafer were carried out over a range of 25–400 °C using in situ thin film stress analysis. A universal test machine was used to conduct 180° peel test (ASTM D903‐98) of polyimide film from cooper foil. The residual stress on CuSi (100) wafer decreased in the order 6FDA‐ODA > BTDA‐ODA > ODPA‐ODA > PMDA‐ODA, and the interfacial adhesion strength decreased in the order BTDA‐ODA (5 N mm−2) > ODPA‐ODA > PMDA‐ODA > 6FDA‐ODA. The results may suggest that the morphological structure, degree of crystallinity of chain orientation and packing significantly relate to the residual stress and adhesion strength in polyimide films. Wide‐angle X‐ray diffraction was used for characterizing the molecular order and orientation and X‐ray photoelectron spectroscopy was used for the analysis of components on copper after polyimide films were detached to confirm the existence of copper oxide chemical bonding and to measure the binding energy of elements on the copper surface.CONCLUSION: In this research, it is demonstrated that BTDA‐ODA polyimide has a low residual stress to copper, good adhesion property, good thermal property and low dielectric constant. Therefore, BTDA‐ODA would be expected to be a promising candidate for a two‐layer copper‐clad laminate. Copyright © 2007 Society of Chemical Industry
Identification of novel bacterial plasminogen‐binding proteins in the human pathogen Mycobacterium tuberculosis
Authors: Xolalpa Wendy , Vallecillo Antonio J. , Lara Martha , Mendoza‐Hernandez Guillermo , Comini Marcelo , Spallek Ralf , Singh Mahavir , Espitia Clara 
Published: September 2007

AbstractBinding and activation of human plasminogen (Plg) to generate the proteolytic enzyme plasmin (Plm) have been associated with the invasive potential of certain bacteria. In this work, proteomic analysis together with ligand blotting assays identified several major Plg‐binding spots in Mycobacterium tuberculosis soluble extracts (SEs) and culture filtrate proteins. The identity of 15 different proteins was deduced by N‐terminal and/or MS and corresponded to DnaK, GroES, GlnA1, Ag85 complex, Mpt51, Mpt64, PrcB, MetK, SahH, Lpd, Icl, Fba, and EF‐Tu. Binding of Plg to recombinant M. tuberculosis DnaK, GlnA1, and Ag85B was further confirmed by ELISA and ligand blotting assays. The binding was inhibited by ϵ‐aminocaproic acid, indicating that the interaction involved lysine residues. Plg bound to recombinant mycobacterial proteins was activated to Plm by tissue‐type Plg activator. In contrast with recombinant proteins, M. tuberculosis SE enhanced several times the Plg activation mediated by the activator. Interestingly, GlnA1 was able to bind the extracellular matrix (ECM) protein fibronectin. Together these results show that M. tuberculosis posses several Plg receptors suggesting that bound Plg to bacteria surface, can be activated to Plm, endowing bacteria with the ability to break down ECM and basal membranes proteins contributing to tissue injury in tuberculosis.
Proteomic approach to studying the cytotoxicity of YC‐1 on U937 leukemia cells and antileukemia activity in orthotopic model of leukemia mice
Authors: Chung Jing‐Gung , Yang Jai‐Sing , Huang Li‐Jiau , Lee Fang‐Yu , Teng Che‐Ming , Tsai Sheng‐Chung , Lin Kuei‐Li , Wang Shu‐Fang , Kuo Sheng‐Chu 
Published: September 2007

AbstractTo evaluate the effects of YC‐1 on leukemia cell lines, PI incorporation was used to determine cell viability. YC‐1 induced a dose‐ and time‐dependent decrease in viability and apoptosis in YC‐1‐treated U937 cells. YC‐1‐induced apoptosis is a cyclic guanosine monophosphate (cGMP)‐independent pathway. Proteomic analysis showed that the altered proteins include the significant regulation of HSP70, chaperonin, ATP synthase beta chains, and Chain F. Western blotting and immuno‐cytochemistry stain showed that YC‐1 treatment caused a time‐dependent increase in cytosolic Cytochrome c, pro‐caspase‐9, Apaf‐1, and the activation of caspase‐9 and ‐3. Importantly, the in vivo antileukemia effects of YC‐1 were evaluated in BALB/c mice inoculated with WEHI‐3B orthotopic model. YC‐1 enhanced survival rate and prevented the body weight loss in leukemia mice. The enlargement of spleen and lymph nodes were reduced in YC‐1 treated than that in leukemia mice. H‐E stain of spleen sections revealed that infiltration of immature myeloblastic cells into red pulp was reduced in YC‐1‐treated group. The apoptotic cells of splenocyte were significantly increased in YC‐1 treated than that in leukemia mice by Tdt‐mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. Taken together, we conclude that YC‐1 acted against U937 cells in vitro via a mitochondrial‐dependent apoptosis pathway, and in orthotopic leukemia model, YC‐1 administered antileukemia activity.
Proteomic analysis of rice (Oryza sativa) seeds during germination
Authors: Yang Pingfang , Li Xiaojuan , Wang Xiaoqin , Chen Hui , Chen Fan , Shen Shihua 
Published: September 2007

AbstractAlthough seed germination is a major subject in plant physiological research, there is still a long way to go to elucidate the mechanism of seed germination. Recently, functional genomic strategies have been applied to study the germination of plant seeds. Here, we conducted a proteomic analysis of seed germination in rice (Oryza sativa indica cv. 9311) – a model monocot. Comparison of 2‐DE maps showed that there were 148 proteins displayed differently in the germination process of rice seeds. Among the changed proteins, 63 were down‐regulated, 69 were up‐regulated (including 20 induced proteins). The down‐regulated proteins were mainly storage proteins, such as globulin and glutelin, and proteins associated with seed maturation, such as “early embryogenesis protein” and “late embryogenesis abundant protein”, and proteins related to desiccation, such as “abscisic acid‐induced protein” and “cold‐regulated protein”. The degradation of storage proteins mainly happened at the late stage of germination phase II (48 h imbibition), while that of seed maturation and desiccation associated proteins occurred at the early stage of phase II (24 h imbibition). In addition to α‐amylase, the up‐regulated proteins were mainly those involved in glycolysis such as UDP‐glucose dehydrogenase, fructokinase, phosphoglucomutase, and pyruvate decarboxylase. The results reflected the possible biochemical and physiological processes of germination of rice seeds.
Novel identification of expressed genes and functional classification of hypothetical proteins from Neisseria meningitidis serogroup A
Authors: Bernardini Giulia , Arena Simona , Braconi Daniela , Scaloni Andrea , Santucci Annalisa 
Published: September 2007

AbstractTo implement the 2‐DE database of serogroup A Neisseria meningitidis (MenA) and improve its potential of investigation in bacterial biology, cell extracts were separated by tricine‐SDS‐PAGE and 131 novel proteins were identified by μLC‐ESI‐IT‐MS/MS. These identifications extended to 404, the number of MenA gene expression products characterized at the proteome level, approximately covering 20% of the total ORFs predicted from genome sequence. This technical approach was particularly useful in ascertaining expression of ribosomal as well as hypothetical proteins. Particular attention was paid to functional characterization of hypothetical proteins by means of software analyses and database searches.
Radical copolymerization of alkyl 2‐norbornene‐2‐carboxylate with alkyl acrylates: Facile incorporation of norbornane framework into poly(alkyl acrylate)s
Authors: Ihara Eiji , Honjyo Shingo , Itoh Tomomichi , Inoue Kenzo , Nodono Mitsufumi 
Published: September 2007

AbstractRadical copolymerization of alkyl 2‐norbornene‐2‐carboxylates (alkyl = Me 1a, nBu 1b) with alkyl acrylates (alkyl = ethyl, methyl, and n‐butyl) was investigated. Copolymerization of 1a,b with the alkyl acrylates initiated by 1,1′‐azobis (cyclohexane‐1‐carbonitrile) at 85 °C proceeded to give random copolymers, although the homopolymerization of 1a,b did not proceed efficiently under the same conditions. Typically, bulk copolymerization of 1a with ethyl acrylate in a feed ratio of 1:3 ([1a]:[EA]) afforded a copolymer with Mn = 33,300 containing 19.4 mol % of 1a unit in the composition. An increase of Tg derived from the incorporation of the rigid norbornane framework was observed, although the extent of the temperature rise was rather moderate. The ternary radical copolymerization of 1a,b/alkyl acrylate/N‐phenylmaleimide proceeded to give copolymers with the three repeating units in the main chain. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4597–4605, 2007
Condensation routes to polyaniline and its analogs
Authors: Hall, H. K. , Padias Anne B. , Boone Harold W. 
Published: September 2007

AbstractTo obtain polyanilines which are more structurally perfect than those obtainable by the oxidation of anilines, polycondensation procedures were investigated. Model reactions gave extensive information about yields and about the physical properties of the putative structural polymer units. Condensation of anthraquinones with aromatic diamines using titanium tetrachloride and the unique base, 1,4‐diazabicyclo‐[2.2.2]‐octane Dabco, gave high molecular weight orange polyquinonimines. Alkoxy groups on the anthraquinone ring aided solubility and molecular weight, and appropriately positioned alkoxy groups afforded stereoregular polymers. A bisthiophene benzoquinone also polymerized successfully. Application of the same procedure to 2,5‐dimethyl‐p‐benzoquinone gave stereoregular poly(arylene benzoquinonimines), close analogs of pernigrani line. The factors causing problems in achieving high yields and high molecular weight were identified. Recent synthetic developments in this field are discussed. Reduction of the obtained polyquinonimines proceeded smoothly to the leucoemeraldine analogs. Unlike the results from pernigraniline obtained by oxidative polymerization, no evidence for the formation of the electrically conductive emeraldine form was obtained. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4751–4763, 2007
Posttraumatic stress disorder among parents of children on cancer treatment: a longitudinal study
Authors: Pöder Ulrika , Ljungman Gustaf , von Essen Louise 
Published: September 2007

AbstractThe main aim of this study was to investigate the occurrence of cancer‐related posttraumatic stress disorder (PTSD) among parents of children on cancer treatment. A longitudinal design with assessments at one week (T1), two (T2), and four (T3) months after the child's diagnosis was used. Two hundred and fourteen parents (107 mothers, 107 fathers) participated at T1–T3. The PTSD Checklist Civilian (PCL‐C), a self‐report screening instrument for PTSD, was answered by parents over the telephone. According to the PCL‐C symptom criteria method 33%, more mothers than fathers, score as potential cases of acute stress disorder (ASD) at T1, whereas 28% as potential cases of PTSD at T2 and 22% at T3. The levels of acute‐ and posttraumatic stress symptoms show a linear, descending pattern, and mothers report higher levels than fathers. Half of the parents who score as potential cases of ASD a week after the child's diagnosis score as potential cases of PTSD four months later. The findings illustrate that a group of parents of children with cancer experience serious psychological distress related to their child's disease. A traumatic stress perspective on childhood cancer should be applied to paediatric oncology care and appropriate psychosocial interventions should be offered to parents when needed. Copyright © 2007 John Wiley & Sons, Ltd.
A pilot study on disseminating physical activity promotion among cancer survivors: a brief report
Authors: Pinto Bernardine M. , Rabin Carolyn , Abdow Susan , Papandonatos George D. 
Published: September 2007

AbstractThere is growing evidence that physical activity (PA) can improve quality of life (QOL) and reduce fatigue in cancer survivors. Research staff or healthcare providers have delivered PA interventions to cancer populations. As a first step to dissemination of a previously tested PA intervention, seven American Cancer Society Reach to Recovery volunteers (mean age = 57.4 years) were trained to deliver the telephone‐based intervention to 25 breast cancer survivors (mean age = 52.9 years, 56% Stage 2 cancer, mean of 3.3 years since diagnosis). A single group design was used. The theory‐based intervention consisted of 12 weekly calls to encourage participants to adopt moderate‐intensity PA. Participants' PA, QOL, mood, and fatigue were assessed at baseline, 12, and 24 weeks. Data on intervention feasibility and preliminary effects were collected. The intervention was feasible (mean of 10.7 out of 12 calls were delivered) and acceptable to the volunteers. At 12 weeks, there were significant increases in participants' PA and improvements in fatigue, QOL, and vigor. Effects were maintained at 24 weeks. This pilot study demonstrated that it was feasible for trained volunteers to deliver a telephone‐based PA intervention to breast cancer survivors, and there were positive effects on survivors' PA behavior and psychological outcomes. Copyright © 2007 John Wiley & Sons, Ltd.
Plasmabromination – the Selective Way to Monotype Functionalized Polymer Surfaces
Authors: Wettmarshausen Sascha , Kühn Gerhard , Hidde Gundula , Mittmann Hans‐Ulrich , Friedrich Jörg F. 
Published: September 2007

AbstractIn contrast to other plasma modification processes of polymer surfaces, the bromination is very selective and shows a high yield in CBr groups. The most convenient bromination process was found using bromoform, which was thus preferred to elemental bromine, allyl bromide, vinyl bromide or tert‐butylbromide. The bromoform process give yields in CBr up to 40 CBr or more, with only 2–3% co‐introduction of O‐functionalities whereas allyl bromide results in yields of about 20 CBr and more, but in more than 10% oxygen‐containing by‐products. CBr groups serve as anchoring points for grafting of molecules, oligomers and pre‐polymers of diole or diamine character.
Application of ground‐penetrating radar imagery for three‐dimensional visualisation of near‐surface structures in ice‐rich permafrost, Barrow, Alaska
Authors: Munroe Jeffrey S. , Doolittle Jim A. , Kanevskiy Mikhail Z. , Hinkel Kenneth M. , Nelson Frederick E. , Jones Benjamin M. , Shur Yuri , Kimble John M. 
Published: September 2007

AbstractThree‐dimensional ground‐penetrating radar (3D GPR) was used to investigate the subsurface structure of ice‐wedge polygons and other features of the frozen active layer and near‐surface permafrost near Barrow, Alaska. Surveys were conducted at three sites located on landscapes of different geomorphic age. At each site, sediment cores were collected and characterised to aid interpretation of GPR data. At two sites, 3D GPR was able to delineate subsurface ice‐wedge networks with high fidelity. Three‐dimensional GPR data also revealed a fundamental difference in ice‐wedge morphology between these two sites that is consistent with differences in landscape age. At a third site, the combination of two‐dimensional and 3D GPR revealed the location of an active frost boil with ataxitic cryostructure. When supplemented by analysis of soil cores, 3D GPR offers considerable potential for imaging, interpreting and 3D mapping of near‐surface soil and ice structures in permafrost environments. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative analysis of myofilament protein phosphorylation in small cardiac biopsies
Authors: Zaremba Ruud , Merkus Daphne , Hamdani Nazha , Lamers Jos M. J. , Paulus Walter J. , dos Remedios Cris , Duncker Dirk J. , Stienen Ger J. M. , van der Velden Jolanda 
Published: September 2007

AbstractPhosphorylation of cardiac myofilament proteins represents one of the main post‐translational mechanisms that regulate cardiac pump function. Human studies are often limited by the amount of available tissue as biopsies taken during cardiac catheterization weigh only 1 mg (dry weight). Similarly, investigation of time‐ (or dose‐) dependent changes in protein phosphorylation in animal studies is often hampered by tissue availability. The present study describes quantitative analysis of phosphorylation status of multiple myofilament proteins by 2‐DE and Pro‐Q® Diamond stained gradient gels using minor amounts (˜0.5 mg dry weight) of human and pig cardiac tissue.