bluuebunny/crossref_metadata_2025_split huggingface dataset:
Settling rates for flocculation of iron and manganese ore‐containing suspensions by cationic glycogen
Authors: Brostow Witold , Hagg Lobland Haley E. , Pal Sagar , Singh Ram P. 
Published: August 2008

AbstractNovel flocculants have been synthesized on the basis of glycogen. The efficiency of cationic glycogen can be explained in terms of Singh's qualitative easy approachability model (EAM). The jar test was used previously to evaluate flocculation efficacy, but we have recently shown that a plot of interface height vs. settling times provides a better measure. In accord with the EAM, a one‐to‐one correspondence between settling velocity and radius of gyration of flocculants in various solutions has been demonstrated, providing quantitative proof of the EAM. Now the flocculation efficacy of cationic glycogen is evaluated by determination of settling times in both iron and manganese ore suspensions and compared with the performance of other polymer flocculants. Its superior flocculation efficacy over commercial flocculants and other flocculants synthesized by us is demonstrated. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Melt processing and filler/matrix interphase in carbon nanotube reinforced poly(ether‐ester) thermoplastic elastomer
Authors: Broza Georg , Schulte Karl 
Published: August 2008

AbstractMultiblock poly(ether‐ester) thermoplastic elastomers (PBT/PTMO) are based on semicrystalline poly(butylene terephthalate) (PBT) and amorphous oxytetramethylene (PTMO) blocks. The copolymer was compounded with a filler content up to 10 wt% multi wall carbon nanotubes (MWCNTs) via a masterbatch process, which included milling, high shear mixing in the melt, and extrusion using a twin‐srew extruder. From the compound several compositions of PBT/PTMO with 0.1–2.0 wt% of MWCNTs were prepared. Differential scanning calorimeter analysis showed that the fillers enhance initiation of recrystallisation, i.e. accelerate the nucleation of crystalline segments of PBT/PTMO. The morphology of the obtained nano‐composites shows that MWCNTs are well dispersed in the matrix. Only some discrete nanotubes, apparently protruding from the matrix, could be distinguished on the fracture surface, still covered with a thin interphase matrix layer of PBT/PTMO. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Adsorption of polymers used in drilling fluids on the inner surfaces of carbon steel pipes
Authors: Spinelli Luciana S. , Aquino Aline S. , Lucas Elizabete , d'Almeida Arnaldo R. , Leal Rafael , Martins André L. 
Published: August 2008

AbstractPolymers in drilling fluids tend to adhere to the inside surfaces of metal pipes, improving the lubricity characteristics of the fluid. The present study evaluated the adsorption of polymers from their aqueous solutions on metal surfaces by means of visual observation and contact angle measurements. The polymers tested were xanthan gum, starch, and partially hydrolyzed polyacrylamide (PHPA). The contact angle measurements were carried out to enable calculating the adhesion and adsorption energy. The visual observation, although not furnishing quantitative data, agreed with the results of the contact angle measurements. The results show that the tendency of these polymers to be adsorbed on metal surfaces varies as follows: starch > PHPA > xanthan gum. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Characterization of grooves in scratch resistance testing
Authors: Brostow Witold , Chonkaew Wunpen , Mirshams Reza , Srivastava Ashish 
Published: August 2008

AbstractFor a number of polymers with different chemical structures and different properties we have determined scratch resistance and sliding wear (15 scratches along the same groove). We have measured cross section areas after scratching, namely the groove and side top‐ridge areas. Nanohardness after scratching was determined using nanoindentation testing both inside and outside the scratching and sliding wear grooves. Three modes of sliding wear are seen: plowing, cutting with debris formation, and densification. The dominating mode depends on the material and is reflected in nanohardness. In polycarbonate (PC) the nanohardness inside and outside the groove are practically the same; the indenter just plows the material aside without debris formation or densification. Thus, the old measure of wear as the weight of the debris formed is not usable for PC; grooves are present but there is no loosened material. By contrast, in brittle materials such as polystyrene there is debris formation and nanohardness inside the groove decreases after 15 scratching runs. A third type of behavior is seen in polyethylene and polypropylene, namely densification caused by scratching; as a result, nanohardness inside the groove increases after 15 passes of the indenter. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Microhybrids of metal powder incorporated in polymeric matrices: Friction, mechanical behavior, and microstructure
Authors: Brostow Witold , Buchman Alisa , Buchman Eli , Olea‐Mejia Oscar 
Published: August 2008

AbstractThe polymers used as a matrix were low density polyethylene (LDPE) and a thermoplastic elastomer (TPE). The metal particles were Al, Ag, and Ni with micrometer diameters. The metal concentration varied from 0 to 10 wt%. Dynamic and static frictions on tetrafluoropolyethylene and stainless steel as sliding surfaces were determined and tensile tests were performed. Secondary electron and backscattered electron SEM images were taken to determine microstructures of the hybrids. Addition of metal powder to the matrix results in reduction to a minimum of the tensile elastic modulus for low metal concentrations, and increase in the modulus with further addition of metal particles. For the TPE, the tensile modulus exceeds that of the pure material. Small metal particles increase the modulus at lower concentrations than larger ones. Hardness varies with the filler concentration, similarly as tensile modulus does. Backscattered electron SEM images show uniform dispersion of the metal particles at the surfaces and in the bulk. The contrast is enhanced by large differences in atomic numbers between the fillers and the matrices. Ni microparticles in LDPE cause crack arrest seen in SEM. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Effect of the filler characteristics on the miscibility of styrene‐butadiene rubber and nitrile‐butadiene rubber blends
Authors: Pérez León D. , Sierra Ligia , López Betty L. 
Published: August 2008

AbstractStyrene‐butadiene rubber (SBR) and nitrile‐butadiene rubber (NBR) blends are immiscible. Fillers can be used as compatibilizers. The SBR + NBR blends reinforced with a mesoporous silica and a precipitated silica are characterized by studying their miscibility by the determination of rubber bound, their changes in heat capacity at each glass transition temperature, and their mechanical performance. NBR is preferentially located at the silica surface improving its dispersion. Larger rubber + filler as well as SBR + NBR interphases are obtained for the blends reinforced with the mesoporous silica, whose high surface area and organized porous structure allow a better polymer + filler interaction. The reinforced blends present higher strength at break than each reinforced polymer alone. The best performance is attained for blends reinforced with mesoporous silica. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Environmental stress cracking behavior of bottle and fiber grade poly(ethylene terephthalate) in contact with aqueous amine solutions
Authors: Sanches Nadir de B. , Dias Marcos L. , Pacheco Elen B.A.V. 
Published: August 2008

AbstractThe environmental stress cracking (ESC) resistance of commercial virgin bottle and fiber grade poly(ethylene terephthalate) (PET) in contact with aqueous amine solutions was investigated. The ESC resistance, in terms of time to failure, was evaluated taking into account some factors, such as test temperature, molar volume (Vo) of the ESC agent, and molecular weight and degree of crystallinity (Xc) of PET. The specimens were tested in flexural mode using a constant load flexural creep test apparatus and also in tensile mode using a dynamometer. After the creep tests, the specimens were photographed with a digital camera and analyzed by scanning electron microscopy (SEM). It was found that ESC resistance was higher with the increase of ESC agent molar volume as well as with the increase of molecular weight and degree of crystallinity of PET. The highest temperature (60°C) lowered the ESC resistance of the specimens, except for the crystalline specimens in n‐butylamine that exhibited a higher ESC resistance at 60°C, which can probably be attributed to the induced crystallization of the remaining amorphous phase by the plasticizing effect of n‐butylamine. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Thermal and low‐field NMR study on poly(vinylidene fluoride) and their physical mixtures with poly(methyl methacrylate)
Authors: Freire Estevão , Bianchi Otavio , Forte Maria Madalena C. , Preto Mônica , Monteiro Elisabeth E.C. , Tavares Maria Inês B. 
Published: August 2008

AbstractBlends with various proportions of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) were prepared using melt mixing and studied by oscillatory mechanical measurements and low‐field NMR spectroscopy to evaluate the influence of the processing method. The polymers and its blends were processed using a conventional low shear mixing chamber (LSM) and a high shear mixer (HSM). The behavior of all blends lies among those of the pure components, considering the two methods of characterization, and the data suggest phase separation between the two components. The hydrogen spin‐lattice relaxation time of the PVDF/PMMA blends were measured and correlated with the components phases. The results are a contribution to data reported previously in the literature using different analytical methods. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Evaluation of microarray surfaces and arraying parameters for autoantibody profiling
Authors: Balboni Imelda , Limb Cindy , Tenenbaum Jessica D. , Utz Paul J. 
Published: August 2008

AbstractAutoantigen microarrays are being used increasingly to study autoimmunity. Significant variation has been observed when comparing microarray surfaces, printing methods, and probing conditions. In the present study, 24 surfaces and several arraying parameters were analyzed using >500 feature autoantigen microarrays printed with quill pins. A small subset of slides, including FAST®, PATH®, and SuperEpoxy2, performed well while maintaining the sensitivity and specificity of autoantigen microarrays previously demonstrated by our laboratory. By optimizing the major variables in our autoantigen microarray platform, subtle differences in serum samples can be identified that will shed light on disease pathogenesis.
Effect of endgroup modification on dynamic viscoelastic relaxation and motion of hyperbranched poly(ether ketone)s
Authors: Choi Jeongsoo , Chung Jae Woo , Jang Seung‐Hyun , Kwak Seung‐Yeop 
Published: August 2008

AbstractFluoro‐terminated hyperbranched poly(ether ketone) (FHPEK) was synthesized and its end groups were modified with alkyl compounds of different chain lengths, i.e., hexyloxy (C6), dodecyloxy (C12), and octadecyloxy, (C18), to produce alkyl‐modified HPEKs (HPEK‐C6, HPEK‐C12, and HPEK‐C18, respectively). Master curves were constructed by using the time‐temperature superposition principle. The horizontal shift factors, aT, used for the construction of the master curves were fit using the William‐Landel‐Ferry (WLF) equation. From the fitting parameters, the apparent activation energy, Ea, was estimated. With increasing alkyl chain length, the Ea values were found to decrease in the order FHPEK > HPEK‐C6 > HPEK‐C12, and then increase for HPEK‐C18. The average relaxation time, τHN, was determined by fitting of the dynamic moduli G′(ω) and G″(ω) to the empirical Havriliak‐Negami equation. Similarly, the τHN values decreased in the order of FHPEK > HPEK‐C6 > HPEK‐C12, and then increased for HPEK‐C18. This indicates that the endgroup modification with short alkyl chains (C6, C12) increased the molecular mobility due to the internal plasticization effect of these alkyl chains. Modification with the longer alkyl chain (C18) retarded the molecular motion through an antiplasticization effect caused by summation of nonpolar hydrophobic interactions between long hydrocarbon chains. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2079–2089, 2008
Association of genetic polymorphisms at 8q24 with the risk of prostate cancer in a Japanese population
Authors: Terada Naoki , Tsuchiya Norihiko , Ma Zhiyong , Shimizu Yosuke , Kobayashi Takashi , Nakamura Eijiro , Kamoto Toshiyuki , Habuchi Tomonori , Ogawa Osamu 
Published: August 2008

AbstractBACKGROUNDGenetic factors, as well as a combination of environmental factors, contribute to the risk of prostate cancer (PC). Recently, genome‐wide linkage studies found several independent single nucleotide polymorphisms (SNPs) that are strongly associated with PC on chromosome 8q24.METHODSWe analyzed two of these SNPs, rs1447295 and rs6983267, to examine association with the risk of PC in Japanese men. These SNPs were examined by a mismatch PCR‐RFLP method in 507 PC patients (286 aggressive and 221 non‐aggressive) and in 511 non‐PC patients (124 benign prostatic hyperplasia and 387 normal male controls) and the allele frequencies were then compared between groups.RESULTSThe rs1447295 A allele was associated with susceptibility to PC (PC vs. non‐PC: P = 0.041; OR, 1.28; 95%CI = 1.01–1.61), and was more significantly associated with disease in aggressive PC (aggressive PC vs. normal controls, P = 0.013; OR, 1.43; 95%CI = 1.08–1.90). The rs6983267 G allele did not show significant association with susceptibility to PC (PC vs. non‐PC: P = 0.967; OR, 1.00; 95%CI = 0.83–1.21). However, it was associated with disease in non‐aggressive PC (non‐aggressive PC vs. normal controls: P = 0.0068; OR, 1.43; 95%CI = 1.10–1.85).CONCLUSIONSThe two SNPs at 8q24 were associated with an increased risk of prostate cancer and contributed to tumor aggression in Japanese men. Prostate 68: 1689–1695, 2008. © 2008 Wiley‐Liss, Inc.
Imaging the effects of castration on bone turnover and hormone‐independent prostate cancer colonization of bone
Authors: Cross N.A. , Fowles A. , Reeves K. , Jokonya N. , Linton K. , Holen I. , Hamdy F.C. , Eaton C.L. 
Published: August 2008

AbstractINTRODUCTIONTumor populations may selectively colonize bone that is being actively remodeled. In prostate cancer patients, androgen deprivation directly inhibits tumor growth initially, whilst induced bone loss may facilitate tumor colonization of bone by androgen‐insensitive cells. We have tested this hypothesis using a xenograft model of early growth of prostate cancer in bone.METHODSPC3 cells transfected with Green fluorescent protein (GFP) were injected into castrated and non‐castrated athymic mice via intrabial and intracardiac routes. In vivo tumor growth was monitored daily and animals sacrificed 6–9 days following initial GFP‐based detection of tumors. Tumor bearing and contra‐lateral non‐tumor bearing tibias were analyzed extensively by micro‐CT and histology/immunohistochemistry for the presence of tumor cells and the effects of tumor and/or castration on bone cells and bone structure evaluated.RESULTSGFP‐positive tumors in bone were visible from 12 days post‐injection following intratibial injection, allowing tumors <1 mm diameter to be monitored in live animals. Castration did not affect tumor frequency, tumor volume, or time to initial appearance of tumors injected via intratibial or intracardiac routes. Castration decreased trabecular bone volume in all mice. Significant tumor‐induced suppression of numbers of osteoblasts, coupled with increased numbers of activated osteoclasts, was evident in both intact animals and castrated animals.CONCLUSIONSIn vivo GFP imaging allows the detection of early tumor growth at intra‐osseous sites. Castration induces bone loss, but PC3‐GFP cells are also capable of inducing bone remodeling in intact animals at early time points, independently of pre‐existing castration‐induced alterations to bone. Prostate 68: 1707–1714, 2008. © 2008 Wiley‐Liss, Inc.
Induction of FLIP expression by androgens protects prostate cancer cells from TRAIL‐mediated apoptosis
Authors: Raclaw Kristin A. , Heemers Hannelore V. , Kidd Emily M. , Dehm Scott M. , Tindall Donald J. 
Published: August 2008

AbstractBACKGROUNDProstate tumors initially regress in response to androgen‐ablation therapy. However, most cancers eventually relapse with an androgen‐depletion‐independent (ADI) phenotype that is often more aggressive than the original androgen‐dependent (AD) tumor. Importantly, most relapsed tumors still rely upon androgen receptor (AR) activity for proliferation and survival. The cellular Fas/FasL‐associated death domain protein‐like inhibitory protein (FLIP) inhibits activation of procaspase‐8 by death receptor‐mediated signaling at the cell surface. In the current study, we examined the androgenic regulation of FLIP and its contribution to protecting prostate cancer cells from death receptor‐mediated apoptosis.METHODSFLIP expression in tissues from intact and castrated rats as well as androgen‐treated prostate cancer cell lines (LNCaP, C4‐2, LNCaP‐Rf, and DU‐145) was monitored via Real‐Time RT‐PCR and immunoblot. Induction of apoptosis by TRAIL, the death receptor ligand, was determined via microscopic observation and cell counting of fragmented nuclei following fixation and staining with Hoechst 33285.RESULTSFLIP mRNA and protein expression was reduced following castration in multiple rat tissues, including dorsolateral prostate and seminal vesicles. Androgenic induction of FLIP mRNA and protein was observed in isogenic AD LNCaP and ADI LNCaP‐Rf cells, but not the isogenic ADI C4‐2 cell line. Protection from TRAIL‐induced apoptosis by androgen was completely blocked when LNCaP‐Rf cells were depleted of endogenous FLIP via siRNA transfection.CONCLUSIONSAndrogenic protection from TRAIL‐induced apoptosis is predominantly via enhanced transcription of FLIP in prostate cancer cells. Loss of androgen‐sensitivity in ADI prostate cancer cells highlights this pathway as a potential target for future therapy of prostate cancer. Prostate 68: 1696–1706, 2008. © 2008 Wiley‐Liss, Inc.
The dietary bioflavonoid, quercetin, selectively induces apoptosis of prostate cancer cells by down‐regulating the expression of heat shock protein 90
Authors: Aalinkeel Ravikumar , Bindukumar B. , Reynolds Jessica L. , Sykes Donald E. , Mahajan Supriya D. , Chadha Kailash C. , Schwartz Stanley A. 
Published: August 2008

AbstractBACKGROUNDHuman and animal studies have suggested that diet‐derived flavonoids, in particular quercetin may play a beneficial role by preventing or inhibiting oncogenesis, but the underlying mechanism remains unclear. The aim of this study is to evaluate the effect(s) of quercetin on normal and malignant prostate cells and to identify the target(s) of quercetin's action.METHODOLOGYWe addressed this question using cells in culture and investigated whether quercetin affects key biological processes responsible for tumor cell properties such as cell proliferation and apoptosis and also studied the effect of quercetin on the proteome of prostate cancer cells using difference gel electrophoresis (DIGE) to assess changes in the expression of relevant proteins.RESULTSOur findings demonstrate that quercetin treatment of prostate cancer cells results in decreased cell proliferation and viability. Furthermore, we demonstrate that quercetin promotes cancer cell apoptosis by down‐regulating the levels of heat shock protein (Hsp) 90. Depletion of Hsp90 by quercetin results in decreased cell viability, levels of surrogate markers of Hsp90 inhibition (intracellular and secreted), induced apoptosis and activation of caspases in cancer cells but not in normal prostate epithelial cells. Knockdown of Hsp90 by short interfering RNA also resulted in induction apoptosis similar to quercetin in cancer cells as indicated by annexin V staining.CONCLUSIONOur results demonstrate that quercetin down‐regulates the expression of Hsp90 which, in turn, induces inhibition of growth and cell death in prostate cancer cells while exerting no quantifiable effect on normal prostate epithelial cells. Prostate © 2008 Wiley‐Liss, Inc.
Single‐beam pumped coherent anti‐Stokes Raman scattering on carbon nanotubes
Authors: Lefrant Serge , Buisson Jean‐Pierre , Mevellec Jean‐Yves , Baltog Ioan , Baibarac Mihaela 
Published: August 2008

AbstractGiant optical fields locally generated in nanoscale metal structures through the local excitation of surface plasmons underlie a variety of nonlinear optical processes. Using silver and gold rough metallic films, reproducible enhancements of the Raman signal on various materials including carbon nanotubes have been demonstrated. In addition, an abnormal anti‐Stokes Raman emission, reminiscent of Coherent anti‐Stokes Raman Scattering (CARS), is accurately observed on nanometric thin films. We demonstrate that under a tight focusing of the excitation light, a CARS‐type emission, resulting from a wave mixing process between the incident laser light and Stokes Raman light generated by a SERS mechanism, is produced. The results which corroborate the CARS emission are the following: a square relation between the CARS signal intensity and the film thickness; a square relationship between the CARS signal intensity and the exciting laser intensity; a dependence of the CARS intensity on the numerical aperture (NA) of the microscope objective used for the detection of the anti‐Stokes signal; a polarization ratio in the anti‐Stokes side always greater in comparison with that measured for an usual Stokes Raman signal. We demonstrate also that this mechanism may contribute to a clear identification of the state of the observed nanotubes, i.e. in isolated or bundled forms, even when tubes are in powders. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of ultrafast intraband relaxation in carbon nanotubes
Authors: Hirtschulz Matthias , Milde Frank , Malic Ermin , Thomsen Christian , Reich Stephanie , Knorr Andreas 
Published: August 2008

AbstractUltrafast intraband carrier relaxation in carbon nanotubes can be described by Carbon Nanotube Bloch Equations (CNBE) treating the Coulomb interaction beyond the Hartree‐Fock level to include carrier‐carrier scattering. We obtain equations of motion for carrier densities and two‐particle carrier correlations that are solved numerically. The complex non‐Markovian relaxation dynamics of hot electrons is calculated for various carbon nanotubes of different diameter and chirality. All calculated nanotubes show an ultrafast relaxation to equilibrium within approximately 100 femtoseconds. The observed relaxation is only weakly dependent on chirality, but depends on the diameter of the nanotube. With increasing diameter of the CNT the relaxation is slowed down, because of the weaker Coulomb interaction in larger diameter CNT. Additionally, we find oscillations of the electron plasma that are due to memory effects in the electron equilibration. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)