bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of aromatic sulphonic acids by CZE in coated and non‐coated capillaries
Authors: Fischer Jan , Jandera Pavel , Česla Petr , Staněk Václav 
Published: July 2003

AbstractCapillary zone electrophoresis (CZE), besides ion‐pairing mode HPLC and salting‐out HPLC, is well‐suited for the analysis of aromatic sulphonic acids widely used as intermediates in the production of synthetic dyes and optical brighteners. The separation selectivity in CZE of many aromatic acids, including positional isomers, can be controlled by the type and concentration of a cyclodextrin additive. The influence of the concentration of β‐cyclodextrin in the working electrolyte on the separation of the positional isomers of naphthalene (poly‐)sulphonic acids, and their amino‐ and hydroxy derivatives, by CZE was studied, both in non‐coated fused silica capillaries and in capillaries coated with polyacrylamide. The migration time scale was calibrated using 4‐alkylbenzenesulphonic acids as the calibration standards. Limiting mobilities of the free acid anions and of their complexes with β‐cyclodextrin were calculated and the effect of the inclusion guest‐host complex formation on the CZE separation was quantitatively characterized. The migration order in coated capillaries is reversed with respect to CZE in non‐coated fused silica capillaries, the separation selectivity is different and the separation of polysulphonic acids such as naphthalene tri‐ and tetrasulphonic acids is significantly accelerated.
Regenerative Recycling of Automotive Polymer Components: Poly(propylene) Based Car Bumpers
Authors: Luda Maria Paola , Ragosta Giuseppe , Musto Pellegrino , Acierno Domenico , Di Maio Luciano , Camino Giovanni , Nepote Valeriano 
Published: July 2003

AbstractThere is a dramatic loss in the mechanical performances at the end of the first life application of bumpers made by a poly(propylene) matrix (PP) and an ethylene‐propylene rubber copolymer as dispersed phase. The use of specific additives during the recycling strongly enhances the mechanical properties of these items. The on purpose designed additive contained a regenerative agent and an antioxidant system. The mixing action of the recycling process re‐establishes the phase compatibility; the antioxidants inhibit oxidation, which speeds up the degradation reactions in the recycling process; eventually the regenerative agent joins short chains possessing suitable reactive groups. These three effects play a different role in restoring original material performance in dependence of the recycling process: for instance the regenerative agent may be nearly useless if chain scission is not the dominant process in the recycling operation and the interfacial adhesion between rubber and the matrix does not assure automatically a ductile mechanical behaviour under impact conditions.SEM micrograph of the fractured surface of the used bumper recycled with additives.magnified imageSEM micrograph of the fractured surface of the used bumper recycled with additives.
Non‐Linear Long‐Term Tensile Creep of Poly(propylene)/Cycloolefin Copolymer Blends with Fibrous Structure
Authors: Kolařík Jan , Pegoretti Alessandro , Fambri Luca , Penati Amabile 
Published: July 2003

AbstractThe tensile deformation of materials with Poisson's ratio smaller than 0.5 generates an additional free volume, which means that tensile creep under constant stress and temperature is a non‐iso‐free volume process. Fractional free volume rising proportionally to the creep strain accounts for a continuous shortening of retardation times. To account for this effect, “internal” time has been introduced which is related to a hypothetical pseudo iso‐free‐volume state. The shift factor along the time scale in the time‐strain superposition is not constant for an isothermal creep curve, but rises monotonically from point to point with the elapsed creep time. The reconstructed compliance dependencies obtained for various stresses approximately obey the time‐strain superposition thus forming a generalised creep curve. A routinely used empirical equation has been found suitable to describe the effects of time and stress on compliance of parent polymers and their blends. The previously proposed predictive format for the time‐dependent compliance of polymer blends has been found applicable also to poly(propylene) (PP)/cycloolefin copolymer (COC) blends with fibrous morphology. As COC shows a tendency to form fibres in a PP matrix, the mixing rule customarily used for fibre composites has been found more appropriate for injection moulded specimens than the equivalent box model for isotropic blends. The predicted compliance curve for a pseudo iso‐free‐volume state can be transformed into a “real” curve for a selected stress σ (in the interval up to the yield stress).SEM microphotograph of the fractured surface (perpendicular to the injection direction) of the PP/COC blend 60/40.magnified imageSEM microphotograph of the fractured surface (perpendicular to the injection direction) of the PP/COC blend 60/40.
Use of Acrylic Functionalized (Meth)acrylic Cross‐Linked Polymer Microparticles in Photopolymerized Acrylic Films
Authors: Valette Ludovic , Pascault Jean‐Pierre , Magny Benoît 
Published: July 2003

AbstractThe effect of reactive (meth)acrylic cross‐linked polymer microparticles (reactive CPM, also called reactive microgels) used as cross‐linking agents has been studied on the thermo‐mechanical properties of different photopolymerized thin films. The matrix was based on the copolymerization of isobornyl acrylate and ethoxy ethoxy ethyl acrylate or butyl acrylate. Various concentrations of CPM were initially blended with the monomers. These solutions were photopolymerized under UV radiation to obtain hard and transparent films. Since CPM were reactive respect to monomers, they acted as multifunctional cross‐linkers, resulting in networks after polymerization. The well distributed and highly functional CPM which connected acrylate linear chains worked as well defined chemical clusters and gave to the networks a very unique structure. By varying the reactive CPM concentration, the relationship between the number of double bonds introduced into the network by the CPM acting like cross‐linkers and the rubbery modulus of the films was determined from viscoelastic measurements. The structure of CPM, the average functionality and also crystallinity were modified to change networks properties. In addition, reactive groups have been preferentially introduced at the surface vicinity by using a new functional stabilizing agent. CPM were also compared to linear polymers with the same composition. From viscoelastic properties, it is concluded that CPM are very efficient cross‐linkers. However, very high CPM incorporation led to high extent of intramolecular reaction, reducing the cross‐linking efficiency. During thermal aging, CPM and linear copolymer seemed to rearrange leading the film structure to an equilibrium state.TEM micrograph of a photopolymerized film (30 wt.‐% of CPM‐0% ODA + 70 wt.‐% of IBOA/EEEA) after thermal aging.magnified imageTEM micrograph of a photopolymerized film (30 wt.‐% of CPM‐0% ODA + 70 wt.‐% of IBOA/EEEA) after thermal aging.
In‐Situ Fiberized Poly(ethylene terephthalate) as a Reinforcement to Poly(propylene) Matrix
Authors: Shen Jing‐Wei , Huang Wen‐Yi , Zuo Sheng‐Wu 
Published: July 2003

AbstractThe reinforced poly(propylene) (PP)/poly(ethylene terephthalate) (PET) in‐situ fiberized composites were prepared by extrusion‐drawing‐injection molding. The influences of PET weight fraction (fw) on the PET fiberization, phase morphology, and mechanical properties of the composites, together with their functional mechanisms were studied by contrast to the normal‐blended materials without drawing. The results show that as the fw rises from 0 to 20%, the number of PET fibers increases, whereas their diameter and dispersity decrease till fw = 15% and then increase, and the number of remained PET particles tends to rise. These changes of PET fiberization and phase morphology with fw were attributed to the consequence of the combined actions of breakup, coalescence, and deformation of the PET dispersed phase in the PP matrix during the extrusion drawing. Correspondingly, the tensile strength (σt) and Young's modulus (E) of the in‐situ composites increase till fw = 15% and then decrease, with maximum gains of σt and E of about 20 and 70% relative to the neat PP, respectively. This σt/fw relation was ascribed to the counterbalanced result between the reinforcing effect of the dispersed phase on matrix and the interfacial flaw effect of two immiscible phases, while the E/fw relation was considered as a representation of the rigidizing effect of the fibers on the matrix being controlled by both their number and diameter.In‐situ PET fibres (PET/PP = 85/15) in an as‐drawn filament.magnified imageIn‐situ PET fibres (PET/PP = 85/15) in an as‐drawn filament.
Some Mechanical Properties of Poly[(acrylic acid)‐co‐(itaconic acid)] Hydrogels
Authors: Rodríguez Elena , Katime Issa 
Published: July 2003

AbstractTwo series of hydrogels of poly[(acrylic acid)‐co‐(itaconic acid)] have been prepared by copolymerization in solution using tetrafunctional N,N′‐methylenebisacrylamide (NMBA) as cross‐linker. The resulting polymer was swollen in water at 298 K to yield homogenous transparent hydrogels. These hydrogels were characterized in terms of swelling and compression‐strain measurements. The influence of the comonomer composition and concentration of cross‐linking agent on volumetric swelling and the mechanical properties of these hydrogels were investigated. Inefficient cross‐linking is indicated by the small values of νe relative to the theoretical cross‐linking densities.Dependence of measured affective cross‐linking density (νe) on the theoretical cross‐linking density (νt) for acrylic acid/itaconic acid hydrogels prepared at a fixed composition of AA80/AI20 wt.‐%, but at different concentrations of NMBA.magnified imageDependence of measured affective cross‐linking density (νe) on the theoretical cross‐linking density (νt) for acrylic acid/itaconic acid hydrogels prepared at a fixed composition of AA80/AI20 wt.‐%, but at different concentrations of NMBA.
Effect of a single dose of polychlorinated biphenyls on hepatic cell proliferation and the DNA binding activity of NF‐κB and AP‐1 in rats
Authors: Lu Zijing , Tharappel Job C. , Lee Eun Y. , Robertson Larry W. , Spear Brett T. , Glauert Howard P. 
Published: July 2003

AbstractPolychlorinated biphenyls (PCBs) are environmental pollutants that, because of their persistence and biomagnification, raise concerns about the health consequences of long‐term exposure. PCB mixtures induce hepatocellular carcinomas in rodents, but the mechanism of their promoting activity is not clear. Previous studies have shown that oxidative stress occurs after PCB administration, with the induction of lipid peroxidation and oxidative DNA damage, which may contribute to their promoting activity. In this study, we examined whether the oxidative stress‐sensitive transcription factors NF‐κB or AP‐1 were activated by PCBs in the liver. Male Sprague‐Dawley rats were injected i.p. with corn oil, 2,2′,4,4′,5,5′‐hexachlorobiphenyl (PCB‐153, 30, 150, or 300 μmol/kg), 3,3′,4,4′‐tetrachlorobiphenyl (PCB‐77, 30, 150, or 300 μmol/kg), or both PCBs (each 30 or 150 μmol/kg). Rats were euthanized 2, 6, or 24 h, or 2, 6, and 10 d after the PCB injection. Electrophoretic mobility shift assays (EMSAs) were performed to determine NF‐κB and AP‐1 DNA binding activities. The highest NF‐κB DNA binding activity was observed in rats receiving higher doses of PCB‐153 (150 and 300 μmol/kg), with peak activation occurring 2 d after injection. AP‐1 activation was not detected at any timepoint. Hepatocyte proliferation, as measured by the labeling index, was increased only in groups receiving the highest dose of PCB‐153 or the combination of two PCBs (150 μmol/kg each) at day 2, and not by any other PCB treatment at any timepoint. These results show that PCB‐153, but not PCB‐77, can induce hepatocyte proliferation and hepatic NF‐κB activation after a single dose. © 2003 Wiley‐Liss, Inc.
Gene expression changes following androgen receptor elimination in LNCaP prostate cancer cells
Authors: Eder Iris E. , Haag Petra , Basik Mark , Mousses Spyro , Bektic Jasmin , Bartsch Georg , Klocker Helmut 
Published: July 2003

AbstractWe have shown recently that inhibition of androgen receptor (AR) expression with an antisense AR oligonucleotide (ODN) inhibits LNCaP prostate tumor cells in vitro as well as in vivo. In this study, we investigated gene expression changes that occur after AR signaling blockade, either through AR elimination by antisense treatment or through complete androgen receptor inhibition by androgen deprivation combined with the antiandrogen bicalutamide, in order to search for genes that are directly or indirectly regulated through the AR. Gene expression changes were investigated with cDNA NIH 10K gene microarrays in response to treatment over 48 h. Expression of selected genes was further analyzed by real‐time reverse transcriptase (RT)‐polymerase chain reaction (PCR), Western blotting, and radioimmunoassay. A comparison of antisense‐treated and androgen‐deprived cells revealed several concordances such as significant downregulation of prostate‐specific genes, cell‐cycle regulatory genes, genes of the cholesterol biosynthesis pathway, and several cytoskeletal genes. However, there were also several genes that were differentially regulated. Among the genes that were exclusively changed by treatment with the antisense AR ODN were the insulin‐like growth factor binding protein 2 (IGFBP2) and the phosphatidylinositol‐4‐phosphate 5‐kinase type I alpha (PIP5KIA). On the other hand, complete androgen receptor blockade induced changes in the expression of the prostate overexpressed gene 1 and the S100 calcium binding protein P. In summary, we identified a cohort of interesting genes whose expression was highly affected by elimination of the AR in LNCaP prostate cancer cells. Further investigations are warranted to clarify their role in the AR signaling pathway and their susceptibility as a target for the treatment of prostate cancer. © 2003 Wiley‐Liss, Inc.
Reduced gap junctional intercellular communication and altered biological effects in mouse osteoblast and rat liver oval cell lines transfected with dominant‐negative connexin 43
Authors: Upham Brad L. , Suzuki Junji , Chen Gang , Wang Yurong , McCabe Laura R. , Chang Chia‐Cheng , Krutovskikh Vladimir A. , Yamasaki Hiroshi , Trosko James E. 
Published: July 2003

AbstractGap junctional intercellular communication (GJIC) maintains normal growth and differentiation of cells in a tissue. The intercellular molecules traversing gap junctions are largely unknown, but the molecular weight (MW) cutoff is normally 1200 Da. No differences in dye transfer were observed in normal or vector controls of WB‐F344 rat liver epithelial or mouse osteoblastic MC3T3‐E1 cells with either Lucifer Yellow (LY) with a MW of 457 Da (LY‐457) or LY with a MW of 649 Da (LY‐649). Transfection of a dominant negative‐connexin 43 (Cx43) gene decreased GJIC (>50%) when LY‐649 was used, however, normal GJIC was observed in both cell lines when LY‐457 was used. Therefore, the MW cut off in these clones was considerably less than the wild type. The dominant negative clones of the MC3T3‐E1 cells exhibited over 90% less alkaline phosphatase (ALPase) activity and calcium deposition after the induction of differentiation. Similarly, dominant negative Cx43 inhibited gene expression of ALPase and bone sialoprotein but not osteocalcin in MC3T3‐E1. WB‐F344 cells normally exhibit a biphasic response to 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) where inhibition of GJIC recovers after 2 h, but the dominant negative clones showed no recovery from inhibition of GJIC by TPA. Dominant negative Cx43 also inhibited the formation of network‐like structures by WB‐F344 cells on Matrigel. These results demonstrate that the dominant negative gene transfected into cell types containing the wild‐type connexins result in diminished channel sizes, thus allowing the determination of whether distinct biological endpoints, i.e., differentiation, are dependent upon either small or high MW intercellular signals. © 2003 Wiley‐Liss, Inc.
Polymorphisms of estrogen receptor alpha in prostate cancer
Authors: Tanaka Yuichiro , Sasaki Masahiro , Kaneuchi Masanori , Shiina Hiroaki , Igawa Mikio , Dahiya Rajvir 
Published: July 2003

AbstractEstrogen receptor (ER) α polymorphisms have been shown to be involved in the oncogenesis of several organs. We hypothesize that polymorphisms of the ERα gene are risk factors for prostate cancer. The genotypic distributions of six different loci (codons: 10 T → C, 87 G → C, 243 C → T, 325 C → G, 594 G → A, and intron 1 C → T) of the ERα gene were analyzed in prostate cancer tissues. The DNA from 115 cases of prostate cancer (Japanese population) was analyzed by sequence‐specific polymerase chain reaction (PCR) and direct sequencing to determine the genotypic and allelic frequencies of the six different polymorphic loci of ERα. The relative risk of variant genotype was calculated by comparison with 200 healthy controls. Results of this study showed that the frequency of the variant genotype (C/C) on codon 10 was significantly higher in prostate cancer patients. The odds ratio (OR) was calculated as 3.26 compared to wild‐type (T/T) with a 95% confidence interval (CI) of 1.58–6.73. Allele frequency at codon 10 also differed between groups. No association was found between codon 10 polymorphism and the stage of cancer. Polymorphism was not observed in codon 87, and frequencies of genotypes and alleles at other loci (intron 1, codons 243, 325, and 594) were not statistically different between cancer and controls. The present study suggests that polymorphism in codon 10 of ERα may be a risk factor for prostate cancer. These results are important in understanding the role of ERα polymorphism in the pathogenesis of prostate cancer. © 2003 Wiley‐Liss, Inc.
Microarray analysis of xenograft‐derived cancer cell lines representing multiple experimental models of human prostate cancer
Authors: Glinsky Gennadi V. , Krones‐Herzig Anja , Glinskii Anna B. , Gebauer Gerhard 
Published: July 2003

AbstractExpression analysis of 7129 transcripts was carried out in five human prostate cancer cell lines derived from orthotopic xenografts after one to five passages in nude mice and primary cultures of human normal prostate epithelial (NPE) cells. These experiments identified a consensus class of 214 genes (43 up‐ and 171 downregulated transcripts), expression of which was altered at least twofold in the same direction in all the cell lines relative to NPE cells. To validate the relevance of altered expression behavior of these genes for human prostate cancer, their expression pattern was evaluated in multiple additional experimental and clinical settings. Expression of 170 of these 214 genes (79%) was altered in the same direction in vivo in experimental human prostate tumors in mice. Similarly, the expression of 151 of the 214 genes (71%) was altered in the same direction in M12 cells, a variant of an SV40 large T antigen transformed normal human prostate epithelial cell line selected for increased malignancy in vivo. In clinical samples of human prostate tumors, the changes in transcript expression levels of majority of these genes (85% of downregulated and 76% of upregulated transcripts) are consistent with alterations of their expression pattern in xenograft‐derived cancer cell lines. These results imply that the expression pattern of a large class of genes is consistently altered in multiple experimental models and clinical samples of human prostate cancer and underscore the potential relevance of the xenograft models and cell lines derived from them for expression analysis studies relevant to human cancer. © 2003 Wiley‐Liss, Inc.
Lower risk of Parkinson's disease in an admixed population of European and Indian origins
Authors: Ragothaman Mona , Murgod Uday A. , Gururaj Gopalkrishna , Kumaraswamy Subbakrishna D. , Muthane Uday 
Published: July 2003

AbstractWe studied whether the occurrence of Parkinson's disease (PD) in the Anglo‐Indians, an admixed population of European and Asian Indian origin, differs from Indians living in the same environment. Epidemiological studies show considerably higher prevalence of PD amongst white compared to non‐white populations. Normal Indians contain a ∼40% lower number of melanized nigral neurons compared to Caucasians from the UK. Anglo‐Indians are an admixed population of European and Indian origin. We used the UK Parkinson's Disease Society Brain Bank clinical diagnostic criteria (steps 1 and 2) to diagnose PD in 84 of 493 residents (Indians, 409; Anglo‐Indians, 84) living in elderly homes in Bangalore, India. Of these 84, 80 were Indians (19.5%) and 4 were Anglo‐Indians (4.8%). Occurrence of PD is nearly five times higher amongst Indians compared to the Anglo‐Indians (odds ratio, 3.9; 95% confidence interval, 1.3–12.9). We conclude that an admixture population of European and Indian origins, rather than averaging, might result in reduced occurrences of PD. Hence, studying an admixed population could provide crucial insights into understanding genetic mechanisms in the etiopathogenesis of PD. © 2003 Movement Disorder Society
Head retraction reflex in stiff‐man syndrome and related disorders
Authors: Berger Christian , Meinck Hans‐Michael 
Published: July 2003

AbstractThe head retraction reflex (HRR) is a vestigial withdrawal reflex of the face and is suppressed in healthy subjects. We investigated the prevalence and electrophysiological patterns of the HRR in patients suffering from stiff‐man syndrome (SMS, n = 28) and related disorders, stiff‐limb syndrome (SLS, n = 2), and progressive encephalomyelitis with rigidity and myoclonus (PERM, n = 20). In patients with a positive HRR, the electromyographic (EMG) pattern was analyzed with surface recordings from the orbicularis oculi, sternocleidomastoid, trapezius, and the paraspinal extensor muscles at midthoracic and lumbar levels. On clinical testing, 17 of 28 SMS patients, 10 of 20 PERM patients, and 0 of 2 SLS patients had a positive HRR, ranging from a brief contraction of the neck extensors to violent retropulsion of the upper body. In all muscles, EMG reflex patterns elicited by gentle taps to the face or by electrical stimulation of the trigeminal nerve branches consisted of two components: an early, synchronous, brief burst with the shortest latency in trapezius (12.5–20.0 msec) and a late, asynchronous, longer response with latencies between 44 and 70 msec. We conclude that the HRR is an abnormal cutaneomuscular brainstem reflex that occurs in a considerable proportion of patients with SMS and related disorders. Although neither specific nor particularly sensitive for SMS, presence of the HRR in a setting with otherwise unexplained stiffness and spasms might help to avoid the otherwise frequent misdiagnosis of a psychogenic motor disturbance in patients with SMS. © 2003 Movement Disorder Society