bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic elucidation of comonomer‐induced chemical and physical activation in heterogeneous ziegler‐natta propylene polymerization
Authors: Taniike Toshiaki , Tien Nguyen Binh , Takahashi Shougo , Quoc Vu Thang , Ikeya Mitsuhiro , Terano Minoru 
Published: July 2011

AbstractWe have kinetically elucidated the origins of activity enhancement because of the addition of comonomer in Ziegler‐Natta propylene polymerization, using stopped‐flow and continuously purged polymerization. Stopped‐flow polymerization (with the polymerization time of 0.1–0.2 s) enabled us to neglect contributions of physical phenomena to the activity, such as catalyst fragmentation and reagent diffusion through produced polymer. The propagation rate constant kp and active‐site concentration [C*] were compared between homopolymerization and copolymerization in the absence of physical effects. kp for propylene was increased by 30% because of the addition of a small amount of ethylene, whereas [C*] was constant. On the contrary, both kp (for propylene) and [C*] remained unchanged by the addition of 1‐hexene. Thus, only ethylene could chemically activate propylene polymerization. However, continuously purged polymerization for 30 s resulted in much more significant activation by the addition of comonomer, clearly indicating that the activation phenomenon mainly arises from the physical effects. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Efficient catalysts for ring‐opening polymerization of ε‐caprolactone and β‐butyrolactone: Synthesis and characterization of zinc complexes based on benzotriazole phenoxide ligands
Authors: Tai Yu‐En , Li Chen‐Yu , Lin Chia‐Her , Liu Yi‐Chang , Ko Bao‐Tsan , Sun Ya‐Sen 
Published: July 2011

AbstractA series of efficient zinc catalysts supported by sterically bulky benzotriazole phenoxide (BTP) ligands are synthesized and structurally characterized. The reactions of diethyl zinc (ZnEt2) with CMe2PhBTP‐H, t‐BuBTP‐H, and TMClBTP‐H yield monoadduct [(μ‐BTP)ZnEt]2 (1–3), respectively. Bisadduct complex [(t‐BuBTP)2Zn] (4) results from treatment of ZnEt2 with t‐BuBTP‐H (2 equiv.) in toluene, but treatment of TMClBTP‐H with ZnEt2 in the same stoichiometric proportion in Et2O produces five‐coordinated monomeric complex [(TMClBTP)2Zn(Et2O)] (5). The molecular structures of compounds 1, 4, and 5 are characterized by X‐ray crystal structure determinations. All complexes 1–5 are efficient catalysts for the ring‐opening polymerization of ε‐caprolactone (ε‐CL) in the presence of 9‐anthracenemethanol. Experimental results indicate that complex 3 exhibits the greatest activity with well‐controlled character among these complexes. The polymerizations of ε‐CL and β‐butyrolactone catalyzed by 3 are demonstrated in a “living” character with narrow polydispersity indices (monomer‐to‐initiator ratio in the range of 25–200, PDIs ≤ 1.10). The “immortal” character of 3 provides a way to synthesize as much as 16‐fold polymer chains of poly(ε‐CL) (PCL) with narrow PDI in the presence of a catalyst in a small proportion. The controlled fashion of complex 3 also enabled preparation of the PCL‐b‐poly(3‐hydroxybutyrate) copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis, characterization, and properties of tunable thermosensitive amphiphilic dendrimer‐star copolymers with Y‐shaped arms
Authors: Yuan Weizhong , Zhang Jinchun , Wei Jingren , Yuan Hua , Ren Jie 
Published: July 2011

AbstractNovel and well‐defined amphiphilic dendrimer‐star copolymer poly(ε‐caprolactone)‐block‐(poly(2‐(2‐methoxyethoxy)ethylmethacrylate‐co‐oligo(ethylene glycol) methacrylate))2 with Y‐shaped arms were synthesized by the combination of ring‐opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The investigation of thermal properties and the analysis of crystalline morphology indicate that the high‐branched structure of dendrimer‐star copolymers with Y‐shaped arms and the presence of amorphous P(MEO2MA‐co‐OEGMA) segments together led to the complete destruction of crystallinity of the PCL segments in the dendrimer‐star copolymer. In addition, the hydrophilicity–hydrophobicity transition of the dendrimer‐star copolymer film can be achieved by altering the external temperatures. The amphiphilic copolymers can self‐assemble into spherical nanomicelles in water. Because the lower critical solution temperature of the copolymers can be adjusted by varying the ratio of MEO2MA and OEGMA, the tunable thermosensitive properties can be observed by transmittance, dynamic laser light scattering, and transmission electron microscopy (TEM). The release rate of model drug chlorambucil from the micelles can be effectively controlled by changing the external temperatures, which indicates that these unique high‐branched amphiphilic copolymers have the potential applications in biomedical field. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Effect of Somatosensory Stimulation of Two and Three Nerves on Upper Limb Function in Healthy Individuals
Authors: Sorinola Isaac Olubunmi , Bateman Robert William , Mamy Katherine 
Published: July 2011

AbstractBackground and PurposeImprovement in motor function has been reported in healthy subjects following somatosensory stimulation (SS) of individual upper limb peripheral nerves. This effect could have beneficial applications in rehabilitation, but there is little knowledge of the effects of stimulating multiple upper limb nerves. This study evaluated the effects of SS of two and three nerves on hand function.MethodsA single blind within‐group repeated measures design was utilized. Ten healthy subjects (27.1 ± 5.4 years [mean ± SD], three men) were recruited and, after a familiarization session, were given SS to the ipsilateral hand in a randomized order to two (ulnar and median) and three (ulnar, median and radial) nerves on two occasions separated by at least one week. The time required to complete the Jebsen–Taylor Hand Function Test (JTHFT) and handgrip strength of the ipsilateral hand were measured before and immediately after each SS session.ResultsTotal JTHFT time decreased significantly by an average of 3.58 ± 2.75 s (9.9%; P = 0.003) and 4.10 ± 3.20 s (11.6%; P = 0.003) following SS to two and three nerves, respectively, but no difference between the two was found. Handgrip strength decreased significantly by 1.82 ± 1.91 kgf (P = 0.015) following SS to three nerves only.ConclusionsThis study suggests that SS of three nerves may facilitate motor training but may also induce a reduction in muscle performance. Further studies are needed to determine the clinical implications of these findings for neurological rehabilitation. Copyright © 2011 John Wiley & Sons, Ltd.
Cleavage of cellulose by a CBM33 protein
Authors: Forsberg Zarah , Vaaje‐Kolstad Gustav , Westereng Bjørge , Bunæs Anne C. , Stenstrøm Yngve , MacKenzie Alasdair , Sørlie Morten , Horn Svein J. , Eijsink Vincent G.H. 
Published: July 2011

AbstractBacterial proteins categorized as family 33 carbohydrate‐binding modules (CBM33) were recently shown to cleave crystalline chitin, using a mechanism that involves hydrolysis and oxidation. We show here that some members of the CBM33 family cleave crystalline cellulose as demonstrated by chromatographic and mass spectrometric analyses of soluble products released from Avicel or filter paper on incubation with CelS2, a CBM33‐containing protein from Streptomyces coelicolor A3(2). These enzymes act synergistically with cellulases and may thus become important tools for efficient conversion of lignocellulosic biomass. Fungal proteins classified as glycoside hydrolase family 61 that are known to act synergistically with cellulases are likely to use a similar mechanism.
Emerging treatment options for patients with castration‐resistant prostate cancer
Authors: George Daniel , Moul Judd W. 
Published: July 2011

AbstractBACKGROUNDMost prostate cancer‐related deaths occur in patients with castration‐resistant prostate cancer (CRPC). Recent preclinical and clinical studies have identified intracellular signaling pathways and changes in the tumor and bone microenvironment as potential key drivers of CRPC. This increased understanding of mechanisms associated with CRPC has driven the development of numerous new agents, many of which are poised to alter the current CRPC treatment landscape.METHODSA review of literature was conducted to identify ongoing and planned phase III studies of novel agents to treat CRPC.RESULTSMultiple studies were identified, including novel androgen biosynthesis inhibitors (abiraterone, TAK‐700), androgen‐receptor inhibitors (MDV3100), angiogenesis inhibitors (aflibercept, tasquinimod), endothelin antagonists (zibotentan, atrasentan), a Src tyrosine kinase inhibitor (dasatinib), a novel radiotherapy (radium‐223), and new immunotherapies (ipilimumab and ProstVac). In addition, both sipuleucel‐T (an immunotherapy) and cabazitaxel (third‐generation taxane) and the RANK‐L inhibitor, denosumab, have recently been approved by the US Food and Drug Administration.CONCLUSIONSVarious combinations of these agents could theoretically be used to treat future patients with CRPC by targeting multiple signaling pathways as well as aspects of the tumor and bone microenvironments. Additional research will be needed to understand how to best use these agents and individualize care to optimize CRPC patient outcomes. Prostate 72:338–349, 2012. © 2011 Wiley Periodicals, Inc.
Comprehensive resequence analysis of a 123‐kb region of chromosome 11q13 associated with prostate cancer
Authors: Chung Charles C. , Boland Joseph , Yeager Meredith , Jacobs Kevin B. , Zhang Xijun , Deng Zuoming , Matthews Casey , Berndt Sonja I. , Chanock Stephen J. 
Published: July 2011

AbstractBACKGROUNDGenome‐wide association studies of prostate cancer have identified single nucleotide polymorphism (SNP) markers in a region of chromosome 11q13.3 in men of European decent. A fine‐mapping analysis with tag SNPs in the cancer genetic markers of susceptibility study identified three independent loci, marked by rs10896438, rs12793759, and rs10896449. This study further annotates common and uncommon variation across this region.METHODSA next generation resequence analysis of a 122.9‐kb region of 11q13.3 (68,642,755‐68,765,690) was conducted in 78 unrelated individuals of European background, 1 CEPH trio, and 1 YRI trio.RESULTSIn total, 644 polymorphic loci were identified by our sequence analysis. Of these, 166 variants—118 SNPs and 48 insertion‐deletion polymorphisms (indels)—were novel, namely not present in the 1000 Genomes or International HapMap Projects. We identified 22, 25, 6, and 4 variants strongly correlated (r2 ≥ 0.8) with rs10896438, rs10896449, rs12793759, and rs11228565, respectively. HapMap SNPs were in linkage disequilibrium (r2 ≥ 0.8) with 48%, 69%, 14%, and 60% of SNPs marking bins by rs10896438, rs10896449, rs12793759, and rs11228565, respectively.CONCLUSIONSOur next generation resequence analysis compliments publicly available datasets of European descent (HapMap, build 28 and 1000 Genome, Pilot 1, October 2010), underscoring the value of targeted resequence analysis prior to initiating functional studies based on public databases alone. Increasing the number of common variants enables investigators to better prioritize variants for functional studies designed to uncover the biological basis of the direct association(s) in the region. Prostate 72:476–486, 2012. © 2011 Wiley Periodicals, Inc.
Assessing the risk of lymph node invasion in patients with intermediate risk prostate cancer treated with extended pelvic lymph node dissection. A novel prediction tool
Authors: Briganti Alberto , Capitanio Umberto , Abdollah Firas , Gallina Andrea , Suardi Nazareno , Bianchi Marco , Tutolo Manuela , Salonia Andrea , Freschi Massimo , Rigatti Patrizio , Montorsi Francesco 
Published: July 2011

AbstractBACKGROUNDControversy exists regarding the need for extended pelvic lymph node dissection (ePLND) in patients with intermediate risk prostate cancer (PCa).MATERIALS AND METHODSThe study included 982 consecutive men with intermediate risk PCa (PSA 10–20 ng/ml or cT2b‐c or biopsy Gleason 3 + 4/ 4 + 3) treated with ePLND and radical prostatectomy (RP) at a single center. All patients underwent an anatomically defined ePLND. A novel risk stratification tool was developed by applying the nonparametric tree modeling technique of classification and regression tree analysis (CART) which relied on pre‐operative PSA, clinical stage, biopsy Gleason score, and percentage of positive cores. The area under the receiver characteristic curve (AUC) method was used to quantify the accuracy of the model.RESULTSLymph node invasion (LNI) was found in 81 (8.2%) patients. The CART analyses identified three risk groups of having LNI: a) Low risk: Gleason 3 + 3, cT1c/cT2, PSA 10‐20 ng/ml, or Gleason 3 + 4/4 + 3, ≤63% of positive cores and PSA < 5 ng/ml (risk of LNI: 3.7 and 5.2%, respectively; 64.8% of patients included); b) Moderate risk: Gleason 3 + 4/4 + 3, ≤63% of positive cores and PSA ≥ 5 ng/ml (risk of LNI:14.4%; 23% of patients included); c)High risk: Gleason 3 + 4/4 + 3, % positive cores >63% (risk of LNI:20.1%; 12.% of patients included; P < 0.001). The accuracy of the model was 71%.CONCLUSIONSThe risk of having LNI varies significantly (3.7–20.1%) in patients with intermediate risk PCa. Our predictive tool might help selecting those patients suitable for ePLND, allowing to spare this approach in about 60% of intermediate risk patients. Prostate 72:499–506, 2012. © 2011 Wiley Periodicals, Inc.
Prostate cancer targeting motifs: Expression of ανβ3, neurotensin receptor 1, prostate specific membrane antigen, and prostate stem cell antigen in human prostate cancer cell lines and xenografts
Authors: Taylor Robert M. , Severns Virginia , Brown David C. , Bisoffi Marco , Sillerud Laurel O. 
Published: July 2011

AbstractBACKGROUNDMembrane receptors are frequent targets of cancer therapeutic and imaging agents. However, promising in vitro results often do not translate to in vivo clinical applications. To better understand this obstacle, we measured the expression differences in receptor signatures among several human prostate cancer cell lines and xenografts as a function of tumorigenicity.METHODSMessenger RNA and protein expression levels for integrin ανβ3, neurotensin receptor 1 (NTSR1), prostate specific membrane antigen (PSMA), and prostate stem cell antigen (PSCA) were measured in LNCaP, C4‐2, and PC‐3 human prostate cancer cell lines and in murine xenografts using quantitative reverse transcriptase polymerase chain reaction, flow cytometry, and immunohistochemistry.RESULTSStable expression patterns were observed for integrin αν and PSMA in all cells and corresponding xenografts. Integrin β3 mRNA expression was greatly reduced in C4‐2 xenografts and greatly elevated in PC‐3 xenografts compared with the corresponding cultured cells. NTSR1 mRNA expression was greatly elevated in LNCaP and PC‐3 xenografts. PSCA mRNA expression was elevated in C4‐2 xenografts when compared with C4‐2 cells cultured in vitro. Furthermore, at the protein level, PSCA was re‐expressed in all xenografts compared with cells in culture.CONCLUSIONSThe regulation of mRNA and protein expression of the cell‐surface target proteins ανβ3, NTSR1, PSMA, and PSCA, in prostate cancer cells with different tumorigenic potential, was influenced by factors of the microenvironment, differing between cell cultures and murine xenotransplants. Integrin ανβ3, NTRS1 and PSCA mRNA expression increased with tumorigenic potential, but mRNA expression levels for these proteins do not translate directly to equivalent expression levels of membrane bound protein. Prostate 72:523–532, 2012. © 2011 Wiley Periodicals, Inc.
Organ specific Gst‐pi expression of the metastatic androgen independent prostate cancer cells in nude mice
Authors: Naiki Taku , Asamoto Makoto , Toyoda‐Hokaiwado Naomi , Naiki‐Ito Aya , Tozawa Keiichi , Kohri Kenjiro , Takahashi Satoru , Shirai Tomoyuki 
Published: July 2011

AbstractBACKGROUNDElucidating the mechanisms of metastasis in prostate cancer, particularly to the bone, is a major issue for treatment of this malignancy. We previously reported that an androgen‐independent variant had higher expression of glutathione S‐transferase pi (Gst‐pi) compared with a parent androgen‐dependent transplantable rat prostate carcinoma which was established from the transgenic rat for adenocarcinoma of the prostate (TRAP).METHODSA new cell line, PCai1, was established from the androgen‐independent tumor and investigated its metastatic potential in nude mice. The tumorigenesis of PCai1 cells in vivo was studied by subcutaneous transplantations into nude mice. The growth in the microenvironment of the prostate was studied by orthotopic transplantation of PCai1 cells into nude mice. The metastatic potential of PCai1 cells was studied by tail vein injections. Effects of Gst‐pi knocked down were analysis in PCai1 cells.RESULTSPCai1 frequently formed metastatic lesions in the lung and lymph nodes after orthotopic implantation in the prostate. Intravenous injections of PCai1, metastasis to lung and bone were obvious. PCai1 had strong expression for Gst‐pi, therefore we tried knocked down Gst‐pi. Gst‐pi‐siRNA in vitro significantly suppressed cell proliferation rate. In addition, high levels of intracellular reactive oxygen species (ROS) were recognized in the Gst‐pi knockout.CONCLUSIONSGst‐pi expression of the prostate cancers are dependent on metastatic site, and that Gst‐pi has an important role in adapting prostate cancer for growth and metastasis involving an alteration of ROS signals. Prostate 72:533–541, 2012. © 2011 Wiley Periodicals, Inc.
The VSGB 2.0 model: A next generation energy model for high resolution protein structure modeling
Authors: Li Jianing , Abel Robert , Zhu Kai , Cao Yixiang , Zhao Suwen , Friesner Richard A. 
Published: July 2011

AbstractA novel energy model (VSGB 2.0) for high resolution protein structure modeling is described, which features an optimized implicit solvent model as well as physics‐based corrections for hydrogen bonding, π–π interactions, self‐contact interactions, and hydrophobic interactions. Parameters of the VSGB 2.0 model were fit to a crystallographic database of 2239 single side chain and 100 11–13 residue loop predictions. Combined with an advanced method of sampling and a robust algorithm for protonation state assignment, the VSGB 2.0 model was validated by predicting 115 super long loops up to 20 residues. Despite the dramatically increasing difficulty in reconstructing longer loops, a high accuracy was achieved: all of the lowest energy conformations have global backbone RMSDs better than 2.0 Å from the native conformations. Average global backbone RMSDs of the predictions are 0.51, 0.63, 0.70, 0.62, 0.80, 1.41, and 1.59 Å for 14, 15, 16, 17, 18, 19, and 20 residue loop predictions, respectively. When these results are corrected for possible statistical bias as explained in the text, the average global backbone RMSDs are 0.61, 0.71, 0.86, 0.62, 1.06, 1.67, and 1.59 Å. Given the precision and robustness of the calculations, we believe that the VSGB 2.0 model is suitable to tackle “real” problems, such as biological function modeling and structure‐based drug discovery. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Computed structures of point deletion mutants and their enzymatic activities
Authors: Berrondo Monica , Gray Jeffrey J. 
Published: July 2011

AbstractPoint deletions in enzymes can vary in effect from negligible to complete loss of activity; however, these effects are not generally predictable. Deletions are widely observed in nature and often result in diseases such as cancer, cystic fibrosis, or osteogenesis imperfecta. Here, we have developed an algorithm to model the perturbed structures of deletion mutants with the ultimate goal of predicting their activities. The algorithm works by deleting the specified residue from the wild‐type structure, creating a gap that is closed using a combination of local and global moves that change the backbone torsion angles of the protein structure. On a set of five proteins for which both wild‐type and deletion mutant x‐ray crystal structures are available, the algorithm produces deep, narrow energy funnels within 1.5 Å of the crystal structure for the deletion mutants. To assess the ability of our algorithm to predict activity from the predicted structures, we tested the correlation of experimental activity with several measures of the predicted structure ensemble using a set of 45 point deletions from ricin. Estimates incorporating likely prevalence of active and inactive deletion sites suggest that activity can be predicted correctly over 60% of the time from the active site root‐mean squared deviation of the lowest energy predicted structures. The predictions are stronger than simple sequence organization measures, but more fundamental work is required in structure prediction and enzyme activity determination to allow consistent prediction of activity. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Mössbauer spectroscopy analysis of iron compounds in carboxylated multiwall carbon nanotubes and their ammonium salt
Authors: Jamrozik Agnieszka , Mazurkiewicz Marta , Małolepszy Artur , Stobiński Leszek , Matlak Krzysztof , Korecki Józef , Kurzydłowski Krzysztof Jan , Burda Kvĕtoslava 
Published: July 2011

AbstractDifferent forms of iron compounds embedded in non‐functionalized (as prepared) and functionalized multiwall carbon nanotubes (MWCNTs) were studied. Iron used to catalyze MWCNT synthesis can be found inside nanotubes and built‐in within their walls. Mössbauer spectroscopy was applied to study valence and spin states as well as magnetic ordering of the iron compounds. In the Mössbauer spectra of as prepared MWCNTs the Fe3C carbide provides the main contribution. The content of Fe3C decreases by about 20 and 40% in carboxylated carbon nanotubes (MWCNTs‐COOH) and ammonium salt of carboxylated carbon nanotubes (MWCNTs‐COONH4), respectively. A small amount of α‐Fe and FexCx iron forms are always observed in all studied carbon nanotubes. In MWCNTs‐COOH, additionally, ferrihydrates and/or FexCy with oxygen in the second coordination sphere of iron are present (at a level of about 17%). In MWCNTs‐COONH4 their content increases by a factor of 3. The experimental data shows that the purification and functionalization of as prepared MWCNTs result in removal of about 90% of iron contaminations. Additionally, we observe the modification of iron compounds inside MWCNTs. All these results are important in optimizing the as prepared MWCNT purification process and in finding a new way to produce different Fe phases inside MWCNTs.
Tailoring properties of borohydrides for hydrogen storage: A review
Authors: Rude Line H. , Nielsen Thomas K. , Ravnsbæk Dorthe B. , Bösenberg Ulrike , Ley Morten B. , Richter Bo , Arnbjerg Lene M. , Dornheim Martin , Filinchuk Yaroslav , Besenbacher Flemming , Jensen Torben R. 
Published: July 2011

AbstractHydrogen is recognized as a possible future energy carrier, which can be produced from renewable energy and water. A major challenge in a future ‘hydrogen economy’ is the development of safe, compact, robust, and efficient means of hydrogen storage, in particular for mobile applications. The present review focuses on light metal boron based hydrides, for which the general interest has expanded significantly during the past few years. Synthesis methods, physical, chemical and structural properties of novel boron based hydrides are reviewed along with new approaches for improving kinetic and thermodynamic properties: (i) anion substitution, (ii) reactive hydride composites and (iii) nanoconfinement of hydrides and chemical reactions. The light metal borohydrides reveal a fascinating structural chemistry and have the potential for storing large amounts of hydrogen. A combination of the different approaches may provide a new route to a wide range of interesting energy storage materials in the future.