bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical analysis of block stone displacements in ancient masonry structures: A new method to estimate historic ground motions
Authors: Kamai Ronnie , Hatzor Yossef H. 
Published: November 2007

AbstractAn innovative approach is presented, in which the discontinuous deformation analysis (DDA) method is used to estimate historic ground motions by back analysis of unique structural failures in archaeological sites. Two archaeological sites in Israel are investigated using this new approach and results are presented in terms of displacement evolution of selected structural elements in the studied masonry structure. The response of the structure is studied up to the point of incipient failure, in a mechanism similar to the one observed in the field. Structural response is found to be very sensitive to dynamic parameters of the loading function such as amplitude and frequency.Prior to back analysis of case studies, two validations are presented. Both compare the performance of DDA with analytical solutions and present strong agreement between the two.Using comprehensive sensitivity analyses, the most likely peak ground acceleration (PGA) and frequency that must have driven the observed block displacements are found for the two case studies—the Nabatean city of Mamshit and the medieval fortress of Nimrod in southern and northern Israel, respectively. It is found that horizontal peak ground accelerations (HPGA) of 0.5g and 1g were required to generate the observed deformations in Mamshit and Nimrod, respectively. Although these might seem too high, considering structural and topographic amplifications it is concluded that the analyses suggest ground motions of 0.2g at a frequency of 1.5 Hz for Mamshit and up to 0.4g at a frequency of 1 Hz for Nimrod. These values provide constraints on the seismic risk associated with these regions as appears in the local building code using a completely independent approach. Copyright © 2007 John Wiley & Sons, Ltd.
The iterated sinh transformation
Authors: Elliott David , Johnston Peter R. 
Published: November 2007

AbstractA sinh transformation has recently been proposed to improve the numerical accuracy of evaluating nearly singular integrals using Gauss–Legendre quadrature. It was shown that the transformation could improve the accuracy of evaluating such integrals, which arise in the boundary element method, by several orders of magnitude. Here, this transformation is extended in an iterative fashion to allow the accurate evaluation of similar types of integrals that have more spiked integrands.Results show that one iteration of this sinh transformation is preferred for nearly weakly singular integrals, whereas two iterations lead to several orders of magnitude improvement in the evaluation of nearly strongly singular integrals. The same observation applies when considering integrals of derivatives of the two‐dimensional boundary element kernel. However, for these integrals, more iterations are required as the distance from the source point to the boundary element decreases. Copyright © 2007 John Wiley & Sons, Ltd.
Stereotyping and nurses' recommendations for treating pain in hospitalized children
Authors: Griffin Ruth A. , Polit Denise F. , Byrne Mary W. 
Published: November 2007

AbstractThe purpose of this study was to examine whether nurses' recommendations for managing children's pain were influenced by stereotypes based on children's personal attributes. Three vignettes, in which hospitalized children's sex, race, and attractiveness were experimentally manipulated, were mailed to a national random sample of 700 pediatric nurses; 334 nurses responded. Responses to vignette questions indicated little evidence of stereotyping. Nurses perceived similar levels of pain and recommended similar pain treatments, regardless of sex, race, and attractiveness. Nurses, on average, perceived children's pain at levels consistent with the children's self‐reports and recommended assertive analgesic and non‐pharmacologic pain management strategies. The results appear consistent with prevailing views on providing adequate pain treatment for children. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30:655–666, 2007
Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures
Authors: Yan Lifeng , Tao Wei 
Published: November 2007

AbstractPoly(ethylene glycol) (PEG) was modified with aniline groups at both the end, and then PEG‐PANI rod‐coil block polymers have been synthesized by polymerization of the aniline with the aniline‐modified PEG. FTIR, NMR, and elemental analysis provided the chemical strucutre of the as‐prepared polymers. The achiral rod‐coil copolymer could form different superstructures by means of self‐assembly when adding diethyl ether into its THF solution and the length of PANI segments is a key factor to the superstructures. AFM measurements revealed that they form spring‐like helical superstructures from the short PANI‐containing copolymers while these form fibrous helical superstructures from the longer PANI‐containing copolymer. A possible mechanism of the helical superstructures is suggested in this article and the driving force is believed the π–π stacking of the rigid segment of the copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 12–20, 2008
A kind of novel nonmetallocene catalysts for ethylene polymerization
Authors: Ma Lifu , Sheng Yaping , Huang Qigu , Zhao Yangfeng , Deng Kunxue , Li Junlong , Yang Wantai 
Published: November 2007

AbstractA kind of novel bridged nonmetallocene catalysts was synthesized by the treatment of N,N‐imidazole and N,N‐phenylimidazole with n‐BuLi, and MCl4 (M = Ti, Zr) in THF. Those catalysts were performed for ethylene polymerization after activated by methylaluminoxane (MAO). The effects of polymerization temperature, Al/M ratio, pressure of monomer, and concentration of catalysts on ethylene polymerization behaviors were investigated in detail. Those results revealed that the catalyst system was favorable for ethylene polymerization with high catalytic activity. The polymer was characterized by 13C NMR, WAXD, GPC, and DSC. The result confirmed that the obtained polyethylene featured broad molecular weight distribution around 20, linear structure, and relative low melting temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 33–37, 2008
Synthesis of low‐polydispersity poly(N‐ethylmethylacrylamide) by controlled radical polymerizations and their thermal phase transition behavior
Authors: Xu Jian , Jiang Xiaoze , Liu Shiyong 
Published: November 2007

AbstractControlled radical polymerizations of N‐ethylmethylacrylamide (EMA) by atom transfer radical polymerization and reversible addition‐fragmentation chain transfer processes were investigated in detail for the first time, employing complementary characterization techniques including gel permeation chromatography, 1H NMR spectroscopy, and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. In both cases, relatively good control of the polymerization of EMA was achieved, as revealed by the linear evolution of molecular weights with monomer conversions and the low polydispersity of poly(N‐ethylmethylacrylamide) (PEMA). The thermal phase transitions of well‐defined PEMA homopolymers with polydispersities less than 1.2 and degrees of polymerization up to 320 in aqueous solution were determined by temperature‐dependent turbidity measurements. The obtained cloud points (CPs) vary in the range of 58–68 °C, exhibiting inverse molecular weight and polymer concentration dependences. Moreover, the presence of a carboxyl group instead of an alkyl one at the PEMA chain end can elevate its CP by ∼3–4 °C. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 60–69, 2008
Novel designed polymer–acyclovir conjugates with linker‐controlled drug release and hepatoma cell targeting
Authors: Li Xia , Lu Min , Wu Qi , Lv De‐shui , Lin Xian‐Fu 
Published: November 2007

AbstractTo develop designed polymer–drug conjugates, where the rate of drug liberation and hepatoma cell targeting function could be rationally and widely controlled, we facilely synthesized a series of novel, galactose‐functionalized polymer–acyclovir conjugates with different linkers and first reported the effect of the linker structure including the type of acyclovir‐linked bond (an ester bond or an amide bond) and relative length of the linker between acyclovir and the polymer main chain on release rate and targeting ability of conjugates. In vitro release studies showed that the cumulative released acyclovir from these polymer–acyclovir conjugates was between 24 and 65% in pH 1.2 glycine solution after 7 days. The ester bond more easily underwent hydrolysis than the amide bond. The longer the relative linker length was, the faster the acyclovir was released. The cell recognition experiments visualized using confocal laser scanning microscopy exhibited that the resultant galactose‐functionalized polymer–acyclovir conjugates had evident targeting to hepG2 cells, and targeting ability was also in connection with the relative length of linker. By choosing appropriate linker, cellular internalization of acyclovir could be well achieved. We consider these results to be helpful for the design of multifunctional polymeric prodrugs, in which the required release rate and targeting ability could be rationally controlled by predetermined molecular architecture. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 117–126, 2008
Outer‐sphere electron transfer metal‐catalyzed polymerization of styrene using a macrobicyclic ligand
Authors: Bell Craig A. , Whittaker Michael R. , Gahan Lawrence R. , Monteiro Michael J. 
Published: November 2007

AbstractThe CuBr‐catalyzed polymerizations of styrene in the presence of a macrobicyclic mixed donor (N and S) encapsulating ligand, NH2capten, were carried out in toluene at 60 and 100 °C. The macrobicyclic nature of the ligand ensures that a transition metal ion is effectively encapsulated (caged) within the three‐dimensional cavity, resulting in activation of radicals through an outer‐sphere electron transfer mechanism. The kinetic data showed that the polymerizations were uncontrolled with little “living” behavior. The external orders of reaction in [CuBr], [NH2capten], and [CuBr2] were 0.5, 0.5, and close to zero, respectively, in agreement with the postulated mechanism of little or no deactivation of polymeric radicals and a significant amount of bimolecular termination. Although “living” behavior was not found using the cage ligand, it was decided that it would provide an ideal method for radical coupling experiments to make high‐molecular weight multiblock copolymers from a difunctional PSTY (Br‐PSTY‐Br, PDI = 1.11). The coupling reaction of Br‐PSTY‐Br using CuBr/NH2capten and excess Cu(0) in toluene at 100 °C gave no loss of the starting Br‐PSTY‐Br. Changing the solvent to the aprotic DMSO resulted in a significant increase in the rate of consumption of starting Br‐PSTY‐Br, with over 87% being used in under 10 min at 60 °C. In addition, higher molecular weight species were also formed, suggesting that OSET gives little or no side reactions on this time scale. It was initially thought that to get such high rates of reaction that the SET‐LRP disproportionation mechanism (2Cu(I) → Cu(0) + Cu(II)) was at play. However, UV–Vis experiments of the CuBr/NH2capten showed little or no disproportionation products. This important result suggests that DMSO catalyzes the OSET reaction through the stabilization of the radical‐anion intermediate, which then rapidly fragments to a polymeric radical. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 146–154, 2008
Proteomics studies of pancreatic cancer
Authors: Chen Ru , Pan Sheng , Aebersold Ruedi , Brentnall Teresa A. 
Published: November 2007

AbstractPancreatic cancer is the fourth leading cause of cancer death in the US, only 4% could survive 5 years after diagnosis. Biomarkers are desperately needed to improve earlier, more curable cancer diagnosis and to develop new effective therapeutic targets. The development of quantitative proteomics technologies in recent years offers great promise for understanding the complex molecular events of tumorigenesis at the protein level, and has stimulated great interest in applying the technology for pancreatic cancer studies. Proteomic studies of pancreatic tissues, juice, serum/plasma, and cell lines have recently attempted to identify differentially expressed proteins in pancreatic cancer to dissect the abnormal signaling pathways underlying oncogenesis, and to detect new biomarkers. It can be expected that the continuing evolution of proteomics technology with better resolution and sensitivity will greatly enhance our capability in combating pancreatic cancer.
Overexpression of E‐cadherin and β‐Catenin proteins in metastatic prostate cancer cells in bone
Authors: Saha Baisakhi , Arase Ahren , Imam Sarah S. , Tsao‐Wei Denice , Naritoku Wesley Y. , Groshen Susan , Jones Lawrence W. , Imam S. Ashraf 
Published: November 2007

AbstractBACKGROUNDThe expression of E‐cadherin in the intercellular adhesion of metastatic prostate cancer cells in bone, which is the most prevalent site of metastatic growth, remains elusive.METHODSThe aim of the study was to compare the concurrent membranous expression of E‐cadherin and β‐catenin proteins, the state which is known to be associated with the cellular adhesion function of E‐cadherin, in prostate biopsy tissue specimens by immunohistochemical staining method. The expression patterns of E‐cadherin or β‐catenin were classified as homogeneous (most cells exhibiting positively), heterogeneous (a few scattered patches of cells with positivity) or negative.RESULTSBenign prostate hyperplasia cells exhibited homogeneous expression of both E‐cadherin and β‐catenin in 9 of 11 (82%), whereas the primary prostate cancer cells were homogeneously positive for both proteins only in 4 of 22 (18%) of the cases. The results are similar to those reported in literature. However, in contrast to the primary cancer, a significantly increased frequency of the metastatic prostate cancer cells in bone exhibited homogeneous expression of E‐cadherin and β‐catenin in 12 of 17 (71%) of the cases. A statistically significant association was observed between the overexpression of both proteins and the metastatic prostate cancer cells in bone (Fisher's exact P < 0.001).CONCLUSIONSThe result of the study demonstrated for the first time that the membranous overexpression of E‐cadherin and β‐catenin are significantly associated with the metastatic prostate cancer cells in bone and that the high frequency of expression suggest their involvement in the intercellular adhesion of the metastatic cells in bone. Prostate 68: 78–84, 2008. © 2007 Wiley‐Liss, Inc.
Neural actions of imidacloprid and their involvement in resistance in the Colorado potato beetle, Leptinotarsa decemlineata (Say)
Authors: Tan Jianguo , Salgado Vincent L , Hollingworth Robert M 
Published: November 2007

AbstractBACKGROUND: The development of resistance to imidacloprid in eastern US populations of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), threatens this critical use for neonicotinoid insecticides. Previous pharmacokinetic studies with resistant adult CPBs provided no explanation for the high resistance level (over 200‐fold) to topically applied imidacloprid. The authors assessed the neural activity of imidacloprid by recording spontaneous activity from a motor nerve leaving the isolated central nervous system to compare the sensitivity of the latter to imidacloprid between susceptible and resistant CPBs.RESULTS: On the isolated central nervous system, imidacloprid was initially neuroexcitatory, and neuroinhibitory at higher concentrations. The neuroexcitatory action of imidacloprid was blocked by coapplication of a specific nAChR antagonist, methyllycaconitine, indicating that it is a result of action on nAChRs. The sensitivity to the neuroexcitatory and inhibitory activities of imidacloprid varied independently among individuals in each population. The sensitivity of the central nervous system of resistant CPBs to excitation by imidacloprid did not differ from that of susceptible insects, but the sensitivity to inhibition by imidacloprid was reduced 52‐ to 58‐fold, indicating a possible change in the sensitivity of at least one subgroup of nAChRs.CONCLUSION: This study provides evidence that reduced nerve sensitivity to the blocking action of imidacloprid is associated with imidacloprid resistance in the CPB. Copyright © 2007 Society of Chemical Industry
The structural and functional contribution of N‐terminal region and His‐47 on Taiwan cobra phospholipase A2
Authors: Kao Pei‐Hsiu , Chen Ku‐Chung , Lin Shinne‐Ren , Chang Long‐Sen 
Published: November 2007

AbstractModification of His‐47 and removal of the N‐terminal octapeptide caused a different effect on the structure of Naja naja atra (Taiwan cobra) phospholipase A2 (PLA2). Unlike native enzyme, Ca2+ induced an alteration in the structural flexibility of His‐modified PLA2. Moreover, the spatial positions of Trp residues in His‐modified PLA2 were not properly rearranged toward lipid–water interface in the presence of Ca2+. CD spectra and fluorescence measurement showed that the dynamic properties of Trp residues and the gross conformation of N‐terminally truncated PLA2 were totally different from native enzyme. Although a precipitous drop in the enzymatic activity was observed with modified PLA2, His‐modified PLA2 and N‐terminally truncated PLA2 retained cytotoxicity on inducing necrotic death of human neuroblastoma SK‐N‐SH cells. Our data suggest that structural perturbations elicited by the chemical modification cause a dissociation of enzymatic activity and cytotoxicity of PLA2. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Crossbar assembly of antibody‐functionalized peptide nanotubes via biomimetic molecular recognition
Authors: Yang Linglu , Nuraje Nurxat , Bai Hanying , Matsui Hiroshi 
Published: November 2007

AbstractPreviously, a large scale assembly of nanowires in a parallel array configuration has been demonstrated, and one type of nanowire could interconnect two electrodes in the high‐wire density. However, to assemble nanowires into practical logic‐gate configurations in integrated circuits, we need more than the parallel assembly of nanowires. For example, when the assembling nanowires are monopolar semiconductors, logic gates such as AND, OR and NOR are to be assembled necessarily from two types of semiconducting nanowires, n‐type and p‐type, and some of these nanowires must cross perpendicularly to form a crossbar geometry for the logical operation. In this paper, the crossbar assembly of antibody‐functionalized peptide nanotubes was demonstrated by a new biomimetic bottom‐up technique. Molecular recognition between antigens and antibodies enabled two types of the antibody‐functionalized bionanotubes to place them onto targeted locations on substrates, where their complementary antigens were patterned. When two rectangular pads of antigens, human IgG and mouse IgG, were patterned perpendicularly on an Au substrate by nanolithography and then the antihuman IgG nanotubes and the antimouse IgG nanotubes were incubated on this substrate in solution, these bionanotubes were attached onto corresponding locations to form the crossbar configuration. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Simultaneous analysis of urinary 4,4′‐methylenebis(2‐chloroaniline) and N‐acetyl 4,4′‐methylenebis(2‐chloroaniline) using solid‐phase extraction and liquid chromatography/tandem mass spectrometry
Authors: Shih Wei‐Chung , Chen Ming‐Feng , Huang Chih‐Chun Jean , Uang Shi‐Nian , Shih Tung‐Shen , Liou Saou‐Hsing , Wu Kuen‐Yuh 
Published: November 2007

AbstractAnalysis of 4,4′‐methylenebis(2‐cholroaniline) (MOCA) or its metabolites in urine has been considered as the appropriate method to assess MOCA exposures through inhalation and skin absorption. MOCA and its metabolite, N‐acetyl 4,4′‐methylenebis(2‐chloroaniline) (acetyl‐MOCA), are analyzed using methods either limited by sensitivity or sample preparation. Therefore, a solid‐phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to simultaneously analyze MOCA and acetyl‐MOCA in urine to serve as biomarkers for MOCA exposure. Protein was precipitated by using acetonitrile, and SPE were applied to clean up samples to eliminate the matrix effect and to improve the recovery. The limit of quantitation of this method was at 1.0 ng/mL for MOCA and 0.03 ng/mL for acetyl‐MOCA (signal‐to‐noise (S/N) ratio = 10). Urinary MOCA and acetyl‐MOCA levels in MOCA‐exposed workers were analyzed and quantitated to be 191.9 ± 373.2 (mean ± standard deviation (SD)) and 11.79 ± 23.8 ng/mL (N = 54) with the median values 38.6 and 1.8 ng/mL, respectively. MOCA concentrations are significantly correlated with their corresponding acetyl‐MOCA levels in urine (Spearman correlation coefficient r = 0.916, p < 0.001). These results show that this method has been successfully developed and provides high‐throughput potential to analyze MOCA and acetyl‐MOCA to serve as exposure biomarkers for future study of the potential health effects associated with MOCA exposures. Copyright © 2007 John Wiley & Sons, Ltd.
Absolute and relative quantification of sheep brain prion protein (PrP) allelic variants by matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry
Authors: Morel Nathalie , Andréoletti Olivier , Grassi Jacques , Clément Gilles 
Published: November 2007

AbstractTransmissible spongiform encephalopathies (TSEs) are characterised by the accumulation in the tissues of affected individuals of an abnormal form (PrPSc) of a protein naturally produced by the host, the cellular prion protein (PrPC). In sheep, susceptibility to TSEs is tightly controlled by polymorphism at positions 136 (A or V), 154 (R or H) and 171 (R or Q) of the Prnp gene encoding the prion protein (PrP). Quantification of PrP variants at positions 136, 154 and 171 can be achieved by matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) mass spectrometric analysis of the respective peptides 114–139, 152–159 and 160–171 obtained after tryptic digestion of the PrP protein. In this study we quantified the tryptic peptide 114–139 containing the first polymorphic site. Quantification was either relative, between variants of this peptide, or absolute with respect to the C‐terminally 18O‐labelled peptide obtained by hydrolysing known amounts of recombinant protein with trypsin in HO. After purification of PrPC and PrPSc from the brain of two heterozygous sheep carrying either the ARQ/VRQ or ARR/VRQ genotypes, the proportion of each variant was measured. In the ARQ/VRQ animal, while both variants were equally represented in the normal isoform, the VRQ variant was predominantly found in the abnormal PrP protein, suggesting dissimilar behaviour of the two variants in the pathological process. The situation was even more contrasted in the ARR/VRQ animal where PrPSc was solely composed of the VRQ variant. These two examples clearly illustrate the value of MALDI‐TOF analysis, combined with appropriate immunopurification techniques, in seeking a precise understanding of the influence of PrP polymorphisms on TSE pathogenesis. Copyright © 2007 John Wiley & Sons, Ltd.