bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Soluble Poly(p‐phenylene) Derivatives for PLED Applications
Authors: Saikia Gunin , Singh Ranbir , Sarmah Pranjol Jyoti , Akhtar Mohammad Waseem , Sinha Jasmine , Katiyar Monica , Iyer Parameswar Krishnan 
Published: November 2009

AbstractPPP derivatives with high molecular weights were synthesized and characterized by FT‐IR, 1H, 13C NMR and GPC. The decomposition temperatures of 2a–2c were above 300–400 °C. DSC analysis indicated their nature to be crystalline as all of them exhibited a melt temperature on controlled heating. Optical and electrochemical band gaps was determined using UV/Vis spectroscopy and CV. Single‐layer PLEDs fabricated with 2a–2c displayed high threshold voltages due to high potential barrier for holes. Their EL spectra reveal a small shift in blue peak and the emission form higher wavelength shoulder peak is enhanced.magnified image
Recent Developments Concerning the Dispersion of Carbon Nanotubes in Polymers
Authors: Grady Brian P. 
Published: November 2009

AbstractThe ability to control the dispersion of carbon nanotubes in polymers is key to most applications of nanotube‐polymer composites. This feature article describes recent advances in methods used to disperse carbon nanotubes and considers how these methods affect dispersion on different length scales. It is becoming increasing clear that perfect dispersion is not desired for many applications, in particular for electrical conductivity, and controlling the dispersion is key for proper function of the composite in its intended application.magnified image
A Study of Particle‐Surface Interactions During Olefin Polymerisation in Gas Phase Reactors
Authors: Eriksson Erik J. G. , McKenna Timothy F. L. 
Published: November 2009

AbstractThis work focuses on the heat exchange between a polymer particle and the reactor wall, especially for cases with low gas velocity. The role of different wall materials (or heat transfer conditions) is investigated with an eye to understanding how this influences the likelihood of particle melting, and, indirectly, wall sheeting. The main focus of this work was to simulate the temperature profiles inside growing polymer particles in the vicinity of the reactor wall when it is clean (steel) or covered with a layer of non reactive polymer. As a comparison, we have also simulated the reactor wall as being glass to represent bench scale polymerization equipment. The results from this work can help to understand how for instance wall sheeting can be accelerated if the reactor walls are not clean and how we can compare results from bench scale experiments to industrial scale units.
Modern Analytical Tools essential for Studying Olefin Polymerization
Authors: Hoffmann Michael S. , Nenov Svetlin , Diesing Till , Naundorf Corinna , Fink Gerhard , Klapper Markus , Müllen Klaus 
Published: November 2009

AbstractAs an alternative to inorganic supports, emulsions and organic carriers were developed for metallocene‐catalyzed polyolefin synthesis in the last years. Oil‐in‐oil emulsions based on a perfluorinated solvent provide the possibility to synthesize polymer particles on the nanometer length scale, while the latex particles consisting of polystyrene with different surface functionalities yield particles on the micrometer range. To obtain a deeper insight to the reaction course of both techniques and to the product morphology and fragmentation behavior of the organic carriers, substantial information concerning the kinetics of these reactions is crucial. Thus, standard analytical methods were combined with real‐time video microscopy and laser scanning fluorescence microscopy (LSCFM) of perylene labeled particles for improving these methods for polyolefin synthesis.
Heat Transfer in Gas Phase Olefin Polymerisation
Authors: Tioni Estevan , Broyer Jean Pierre , Spitz Roger , Monteil Vincent , McKenna Timothy F. L. 
Published: November 2009

AbstractA fixed bed microreactor has been used to study heat transfer during the initial transient state of gas phase olefin polymerization on a supported catalyst. It has been shown that heat transfer during this stage of the polymerisation is critical, and under conditions found commercially problems can arise with hot spots and polymer melting. It is proven how the thermal properties of the gas mixture flowing on the catalytic bed exert great influence on heat dissipation reducing the sudden increase in temperature by as much as a factor of 5. Flow rate and especially the process gas composition are the key factors in controlling the bed temperature.
CRYSTAF Analysis of Polyethylene Synthesized with Phillips Catalyst
Authors: Xia Wei , Taniike Toshiaki , Terano Minoru , Fujitani Tadahiro , Liu Boping , Soares João B. P. 
Published: November 2009

AbstractCrystallization analysis fractionation (CRYSTAF) was used for the first time to investigate the solution crystallization behavior of ethylene homopolymers and copolymers made with Phillips CrOx/SiO2 catalyst. Interestingly, the crystallization peak temperatures (Tp) of copolymers of ethylene and cyclopentene increased with increasing cyclopentene molar fraction in the copolymer. Comparing two factors (short chain branches (SCBs) and cyclopentene incorporation), decreasing SCB frequency is proposed as the dominant factor to explain the increase of crystallization peak temperatures with increasing cyclopentene incorporation. In addition, SCB frequency and molecular weight might be the two significant factors determining the crystallization temperature of polyethylene made with Phillips CrOx/SiO2 catalyst with different cocatalysts (triethylaluminum and diethylaluminum ethoxide).
Influence of Metallocene Type on the Order of Ethylene Polymerization and Catalyst Deactivation Rate in a Solution Reactor
Authors: Mehdiabadi Saeid , Soares João B.P. 
Published: November 2009

AbstractThe solution polymerization of ethylene using rac‐Et(Ind)2ZrCl2/MAO and (Dimethylsilyl(tert‐butylamido)(tetramethyl‐ cyclopentadienyl)titanium Dichloride)(CGC‐Ti)/MAO was studied in a semi‐batch reactor at 120 °C under different monomer pressures and catalyst concentrations. The kinetics of ethylene polymerization with rac‐Et(Ind)2ZrCl2/MAO can be described with first order reactions for polymerization and catalyst deactivation. When (CGC‐Ti)/MAO is used, however, second order kinetics are observed for catalyst decay and the order of polymerization changes from 2 to 1 with increasing ethylene pressure.
15N and 13C NMR chemical shifts of 6‐(fluoro, chloro, bromo, and iodo)purine 2′‐deoxynucleosides: measurements and calculations
Authors: Bai Shi , Dmitrenko Olga , Dybowski Cecil 
Published: November 2009

AbstractThe 15N and 13C chemical shifts of 6‐(fluoro, chloro, bromo, and iodo)purine 2′‐deoxynucleoside derivatives in deuterated chloroform were measured. The 15N chemical shifts were determined by the 1H15N HMBC method, and complete 15N chemical‐shift assignments were made with the aid of density functional theory (DFT) calculations. Inclusion of solvation effects significantly improved the precision of the calculations of 15N chemical shifts. Halogen‐substitution effects on the 15N and 13C chemical shifts of purine rings are discussed in the context of DFT results. The experimental coupling constants for 19F interacting with 15N and 13C of the 6‐fluoropurine 2‐deoxynuleoside are compared with those from DFT calculations. Copyright © 2009 John Wiley & Sons, Ltd.
Structural determination of aspericins AC, new furan and pyran derivates from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61, by 1D and 2D NMR spectroscopy
Authors: Wang Fazuo , Zhu Tianjiao , Zhang Min , Lin Aiqun , Zhu Weiming , Gu Qianqun 
Published: November 2009

AbstractThree new furan and pyran derivatives named aspericins AC (1–3), as well as a known asperic acid (4), have been isolated from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61. The complete 1H and 13C NMR assignments for the new compounds were carried out using 1H, 13C, DEPT, COSY, HMQC, HMBC, and NOESY NMR experiments. Compounds 1–3 were evaluated for their cytotoxic activities on P388, A549, HL‐60, and BEL‐7420 cell lines by the MTT and SRB methods. Copyright © 2009 John Wiley & Sons, Ltd.
Skeletal metastatic carcinoma: A case from 15th–20th century Coimbra, Portugal
Authors: Wasterlain S. N. , Ascenso B. F. , Silva A. M. 
Published: November 2009

AbstractThis paper discusses the differential diagnosis of unusual and distinct pathological changes in the skeletal remains of a 40+‐year‐old female from 15th–20th century Coimbra (Portugal). The most affected area seems to have been the skull, but multiple lesions, lytic and/or blastic, have been found throughout the post‐cranial skeleton, more specifically in the scapulae, clavicles, humerus, sternum, ribs, sacrum, innominates and femurs. The differential diagnosis of the lesions gave rise to several possible pathological conditions, namely, Langerhans cell histiocytosis (granulomatosis or Histiocytosis X), multiple myeloma and metastatic carcinoma. Various macroscopic and radiological aspects lead us to consider metastatic carcinoma as the most probable diagnosis. Despite the argumentative identity of the possible primary lesion, age, sex and the mixed nature of the osseous response are consistent with cancer of the breast but do not exclude other carcinomas, namely lung cancer. With temporal and regional differences emerging in the frequency of malignant tumours, the identification of new cases becomes important, particularly from geographic areas where few cases have been reported. In fact, the present report adds to the only case of metastatic carcinoma detected in non‐identified Portuguese human skeletal remains until now. Copyright © 2009 John Wiley & Sons, Ltd.
The role of nuclear organization in cancer
Authors: Lever Elliott , Sheer Denise 
Published: November 2009

AbstractThe functional significance of changes in nuclear structure and organization in transformed cells remains one of the most enigmatic questions in cancer biology. In this review, we discuss relationships between nuclear organization and transcription in terms of the three‐dimensional arrangement of genes in the interphase cancer nucleus and the regulatory functions of nuclear matrix proteins. We also analyse the role of nuclear topology in the generation of gene fusions. We speculate that this type of multi‐layered analysis will one day provide a framework for a more comprehensive understanding of the genetic origins of cancer and the identification of new therapeutic targets. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Potentially amyloidogenic conformational intermediates populate the unfolding landscape of transthyretin: Insights from molecular dynamics simulations
Authors: Rodrigues J. Rui , Simões Carlos J. V. , Silva Cândida G. , Brito Rui M. M. 
Published: November 2009

AbstractProtein aggregation into insoluble fibrillar structures known as amyloid characterizes several neurodegenerative diseases, including Alzheimer's, Huntington's and Creutzfeldt‐Jakob. Transthyretin (TTR), a homotetrameric plasma protein, is known to be the causative agent of amyloid pathologies such as FAP (familial amyloid polyneuropathy), FAC (familial amyloid cardiomiopathy) and SSA (senile systemic amyloidosis). It is generally accepted that TTR tetramer dissociation and monomer partial unfolding precedes amyloid fibril formation. To explore the TTR unfolding landscape and to identify potential intermediate conformations with high tendency for amyloid formation, we have performed molecular dynamics unfolding simulations of WT‐TTR and L55P‐TTR, a highly amyloidogenic TTR variant. Our simulations in explicit water allow the identification of events that clearly discriminate the unfolding behavior of WT and L55P‐TTR. Analysis of the simulation trajectories show that (i) the L55P monomers unfold earlier and to a larger extent than the WT; (ii) the single α‐helix in the TTR monomer completely unfolds in most of the L55P simulations while remain folded in WT simulations; (iii) L55P forms, early in the simulations, aggregation‐prone conformations characterized by full displacement of strands C and D from the main β‐sandwich core of the monomer; (iv) L55P shows, late in the simulations, severe loss of the H‐bond network and consequent destabilization of the CBEF β‐sheet of the β‐sandwich; (v) WT forms aggregation‐compatible conformations only late in the simulations and upon extensive unfolding of the monomer. These results clearly show that, in comparison with WT, L55P‐TTR does present a much higher probability of forming transient conformations compatible with aggregation and amyloid formation.
High‐resolution crystal structure of human Mapkap kinase 3 in complex with a high affinity ligand
Authors: Cheng Robert , Felicetti Brunella , Palan Shilpa , Toogood‐Johnson Ian , Scheich Christoph , Barker John , Whittaker Mark , Hesterkamp Thomas 
Published: November 2009

AbstractThe Mapkap kinases 2 and 3 (MK2 and MK3) have been implicated in intracellular signaling pathways leading to the production of the pro‐inflammatory cytokine tumor necrosis factor alpha. MK2 has been pursued by the biopharmaceutical industry for many years for the development of a small molecule anti‐inflammatory treatment and drug‐like inhibitors have been described. The development of some of these compounds, however, has been slowed by the absence of a high‐resolution crystal structure of MK2. Herein we present a high‐resolution (1.9 Å) crystal structure of the highly homologous MK3 in complex with a pharmaceutical lead compound. While all of the canonical features of Ser/Thr kinases in general and MK2 in particular are recapitulated in MK3, the detailed analysis of the binding interaction of the drug‐like ligand within the adenine binding pocket allows relevant conclusions to be drawn for the further design of potent and selective drug candidates.
Complex formation between human prostate‐specific antigen and protease inhibitors in mouse plasma
Authors: Hekim Can , Riipi Tero , Zhu Lei , Laakkonen Pirjo , Stenman Ulf‐Håkan , Koistinen Hannu 
Published: November 2009

AbstractBACKGROUNDWhen secreted from the prostate, most of prostate‐specific antigen (PSA) is free and enzymatically active. Upon reaching circulation, active PSA is inactivated by complex formation with protease inhibitors. To justify the use of mouse models for evaluation of the function of PSA and for studies on therapeutic modalities based on modulation of PSA activity, it is important to know whether PSA complexation is similar in mouse and man.METHODSTo characterize the circulating forms of PSA in mouse, we used subcutaneous LNCaP and 22RV1 human prostate cancer cell xenograft tumor models. We also added PSA directly to mouse serum. Free and total PSA were measured by immunoassay, and PSA complexes were extracted by immunopurification followed by SDS–PAGE, in‐gel trypsin digestion and identification of signature peptides by mass spectrometry.RESULTSIn mice bearing xenograft tumors, 68% of the immunoreactive PSA occurred in complex, and when added to mouse serum, over 70% of PSA forms complexes that comprises α2‐macroglobulin and members of the α1‐antitrypsin (AAT) family.CONCLUSIONIn mouse plasma, PSA forms complexes similar to those in man, but the major immunoreactive complex contains AAT rather than α1‐antichymotrypsin, which is the main complex forming serpin in man. The complex formation of PSA produced by xenograft tumor models in mice is similar to that of human prostate tumors with respect to the complexation of PSA. Prostate 70: 482–490, 2010. © 2009 Wiley‐Liss, Inc.
Differential phosphoprotein levels and pathway analysis identify the transition mechanism of LNCaP cells into androgen‐independent cells
Authors: Wang Hui Qing , Yang Bo , Xu Chuan Liang , Wang Lin Hui , Zhang Yu Xi , Xu Bin , Ji Jia Tao , Sun Ying Hao 
Published: November 2009

AbstractBACKGROUNDAndrogen withdrawal can prolong life in men with advanced prostate cancer, but these remissions are temporary because the surviving cells progress as hormone‐refractory cancer. The mechanisms that are involved in the transition of androgen‐dependent prostate cancer into androgen‐independent prostate cancer (AIPC) are not fully understood.OBJECTIVETo identify globally differentially expressed phosphoproteins in the androgen‐independent prostate, to elucidate the molecular mechanisms that underlie the formation of AIPC and to identify new molecular targets that can be used to develop treatments for the disease.METHODSAn androgen‐independent LNCaP cell line, LNCaP‐AI, was established using androgen ablation. Differentially expressed phosphoproteins in LNCaP cells and LNCaP‐AI cells were enriched by immunoprecipitation, analyzed by 2D‐PAGE and identified by MALDI‐TOF MS. Total protein expression levels for two regulated proteins were confirmed by Western blot. Association network analysis was carried out using the STRING database.RESULTSThe phosphorylation statuses of 17 proteins were significantly (P < 0.05) different between LNCaP‐AI cells and LNCaP cells. Most proteins that were identified are known to be involved in tumor progression, and several of these proteins could be constructed into an association network. A further analysis by bioinformatics indicated that P53, HSP27, and the MAPK pathway may contribute to the transition from androgen‐dependence to androgen‐independence.CONCLUSIONBlocking the MAPK signaling pathway may be useful in the treatment of AIPC. Prostate 70: 508–517, 2010. © 2009 Wiley‐Liss, Inc.
Nanomaterial standards for efficacy and toxicity assessment
Authors: Adiseshaiah Pavan P. , Hall Jennifer B. , McNeil Scott E. 
Published: November 2009

AbstractDecreased toxicity via selective delivery of cancer therapeutics to tumors has become a hallmark achievement of nanotechnology. In order to be optimally efficacious, a systemically administered nanomedicine must reach cancer cells in sufficient quantities to elicit a response and assume its active form within the tumor microenvironment (e.g., be taken up by cancer cells and release a toxic component once within the cytosol or nuclei). Most nanomedicines achieve selective tumor accumulation via the enhanced permeability and retention (EPR) effect or a combination of the EPR effect and active targeting to cellular receptors. Here, we review how the fundamental physicochemical properties of a nanomedicine (its size, charge, hydrophobicity, etc.) can dramatically affect its distribution to cancerous tissue, transport across vascular walls, and retention in tumors. We also discuss how nanoparticle characteristics such as stability in the blood and tumor, cleavability of covalently bound components, cancer cell uptake, and cytotoxicity contribute to efficacy once the nanoparticle has reached the tumor's interstitial space. We elaborate on how tumor vascularization and receptor expression vary depending on cancer type, stage of disease, site of implantation, and host species, and review studies which have demonstrated that these variations affect tumor response to nanomedicines. Finally, we show how knowledge of these properties (both of the nanoparticle and the cancer/tumor under study) can be used to design meaningfulin vivotests to evaluate nanoparticle efficacy.WIREs Nanomed Nanobiotechnol2010 2 99–112This article is categorized under:Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials
Single HCC smaller than 2 cm: surgery or ablation?
Authors: Takayama Tadatoshi , Makuuchi Masatoshi , Hasegawa Kiyoshi 
Published: November 2009

AbstractPurposeFor hepatocellular carcinoma (HCC), surgical resection and radiofrequency ablation (RFA) are accepted as effective treatments. To clarify the long‐term outcome in patients with small HCC, we analyzed data from a nationwide survey of Japan.MethodsBetween 2000 and 2003, a total of 2,550 patients who had undergone resection (n = 1,235) or RFA (n = 1,315) for single small HCC (≤2 cm) were registered to the database of the Liver Cancer Study Group of Japan (LCSGJ).ResultsAfter a median follow‐up period of 37 months, disease‐free survival after resection was significantly better than after RFA (1‐year, 91 vs. 87%; 2‐year, 46 vs. 25%;P = 0.001), but overall survival after resection and RFA were similar (98 vs. 99%; 94 vs. 95%,P = 0.28). In the patients of Child–Pugh class A, disease‐free survival was significantly better after resection (n = 1,056) than after RFA (n = 965) (P = 0.001), while overall survival was not significantly different (P = 0.16). In the patients of Child–Pugh class B, both disease‐free and overall survival were almost similar (P = 0.63 andP = 0.66) after resection (n = 136) and RFA (n = 303).ConclusionsFor single small HCC (≤2 cm), surgical resection provides better disease‐free survival than does RFA. Longer follow‐up is needed to regard this indication as conclusive.
Architecture and growth of an annual plant Chenopodium album in different light climates
Authors: Nishimura Eriko , Suzaki Emi , Irie Mami , Nagashima Hisae , Hirose Tadaki 
Published: November 2009

AbstractLight climates strongly influence plant architecture and mass allocation. Using the metamer concept, we quantitatively described branching architecture and growth of Chenopodium album plants grown solitarily or in a dense stand. Metamer is a unit of plant construction that is composed of an internode and the upper node with a leaf and a subtended axillary bud. The number of metamers on the main‐axis stem increased with plant growth, but did not differ between solitary and dense‐stand plants. Solitary plants had shorter thicker internodes with branches larger in size and number than the plant in the dense stand. Leaf area on the main stem was not different. Larger leaf area in solitary plants was due to a larger number of leaves on branches. Leaf mass per area (LMA) was higher in solitary plants. It did not significantly differ between the main axis and branches in solitary plants, whereas in the dense stand it was smaller on branches. Dry mass was allocated most to leaves in solitary plants and to stems in the dense stand in vegetative growth. Reproductive allocation was not significantly different. Branch/main stem mass ratio was higher in solitary than dense‐stand plants, and leaf/stem mass ratio higher in branches than in the main axis. Nitrogen use efficiency (NUE) (dry mass growth per unit N uptake) was higher and light use efficiency (LUE) (dry mass growth per unit light interception) was lower in the plant grown solitarily than in the dense stand.
Nanocasting Synthesis of Ultrafine WO3 Nanoparticles for Gas Sensing Applications
Authors: Kamali Heidari Elham , Marzbanrad Ehsan , Zamani Cyrus , Raissi Babak 
Published: November 2009

Abstract
Ultrafine WO3 nanoparticles were synthesized by nanocasting route, using mesoporous SiO2 as a template. BET measurements showed a specific surface area of 700 m 2/gr for synthesized SiO2, while after impregnation and template removal, this area was reduced to 43 m 2/gr for WO3 nanoparticles. HRTEM results showed single crystalline nanoparticles with average particle size of about 5 nm possessing a monoclinic structure, which is the favorite crystal structure for gas sensing applications. Gas sensor was fabricated by deposition of WO3 nanoparticles between electrodes via low frequency AC electrophoretic deposition. Gas sensing measurements showed that this material has a high sensitivity to very low concentrations of NO2 at 250°C and 300°C.