bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyamide 66 nanocomposites based on organoclays treated with thermally stable phosphonium salts
Authors: Abdallah Wissam , Yilmazer Ulku 
Published: May 2012

AbstractPurification of bentonite clays and their modification with two thermally stable (alkyl and aryl) phosphonium organic salts were investigated. The organoclays were subsequently melt compounded with Polyamide 66 (PA66), with and without the use of an elastomeric compatibilizer. The morphology, melt flow, thermal stability, and mechanical properties of the binary and ternary nanocomposites were studied. The bentonite clay was purified by sedimentation, resulting in higher cation exchange capacity and thermal stability in comparison with unpurified clay. These were then used in the synthesis of two thermally stable organoclays by replacing the interlayer sodium cations with two (alkyl and aryl) phosphonium surfactant cations to circumvent the problem of low temperature decomposition of quaternary ammonium organoclays usually used in polymer nanocomposites. The organoclay with aliphatic groups showed more compatibility with PA66 in comparison with the organoclay with aromatic groups. Thus, the use of organoclay with aliphatic groups resulted in nanocomposites with higher tensile strength, higher modulus, higher elongation at break, and higher impact strength in comparison with the nanocomposites produced from the organoclay with aromatic groups. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Conducting poly(styrene‐co‐divinylbenzene)/polypyrrole PolyHIPE composite foam prepared by chemical oxidative polymerization
Authors: Karimian Hossein , Moghbeli Mohammad Reza 
Published: May 2012

AbstractConducting poly(styrene‐co‐divinylbenzene)/polypyrrole (PPy) polyHIPE (polymerized high internal phase emulsion) composite foams were synthesized via chemical oxidative polymerization method. The effect of solvent and dopant type on the surface morphology and electrical conductivity of composite foams has been investigated. SEM micrographs showed that the morphology of PPy thin film on the internal surface of poly(styrene/divinylbenzene) (poly(St‐co‐DVB) polyHIPE support foam strongly depends on the solvent and dopant type used. Incorporation of dodecylbenzene solfunic acid‐sodium salt (DBSNa) as a dopant in chloroform solvent resulted in formation of a PPy thin film with higher molecular compact structure and electrical conductivity on the support foam as compared to other solvents and another dopant used. Fourier‐transform infrared spectroscopy was used to correlate the electrical conductivity of composite foams to their PPy structural parameters. As expected, the extended conjugation length of PPy in the presence of DBSNa dopant is the main reason for higher electrical conductivity of resultant composite foam. Electrical conductivity measurements revealed that the chemical aging of various conducting foams follows the first‐order kinetic model, which is a representative of a reaction‐controlled aging mechanism. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Development of antimicrobial stainless steel via surface modification with N‐halamines: Characterization of surface chemistry and N‐halamine chlorination
Authors: Bastarrachea Luis J. , Goddard Julie M. 
Published: May 2012

AbstractN‐halamine modification of materials enables the development of antimicrobial materials whose activity can be regenerated after exposure to halogenated sanitizers. Surface and bulk modification of polymers by N‐halamines has shown great success, however, modification of inorganic substrates (e.g., stainless steel) remains an area of research need. Herein, we report the covalent surface modification of stainless steel to possess rechargeably antimicrobial N‐halamine moieties. Multilayers of branched polyethyleneimine and poly(acrylic acid) were immobilized onto the surface of stainless steel and the number of N‐halamines available to complex chlorine was quantified. Samples were characterized through contact angle, Fourier transform infrared spectroscopy, ellipsometry, dye assay for amine quantification, and X‐ray photoelectron spectroscopy. Increasing the number of multilayers from one to six increased the number of N‐halamines available to complex chlorine from 0.30 ± 0.5 to 36.81 ± 5.0 nmol cm−2. XPS and FTIR confirmed successful covalent layer‐by‐layer deposition of the N‐halamine multilayers. The reported layer‐by‐layer deposition technique resulted in a greater than seven‐fold increase of available N‐halamine compared to prior reports of N‐halamine surface modifications. The N‐halamine modified steel demonstrated antimicrobial activity (99.7% reduction) against the pathogen Listeria monocytogenes. Such surface modified stainless steel with increased N‐halamine functionality, and therefore potential for rechargeable antimicrobial activity, supports efforts to reduce cross‐contamination by pathogenic organisms in the food and biomedical industries. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The Arrangement of Fascicles in Whole Muscle
Authors: Infantolino Benjamin W. , Neuberger Thomas , Challis John H. 
Published: May 2012

AbstractThe architecture of the muscle fascicles, here meaning their lengths and their arrangement relative to one another, has important implications for the force a muscle can produce. Therefore, quantifying this architectural arrangement and understanding the implications of the architecture are important for understanding muscle function in vivo. There were two purposes of this study: (1) to assess, via blunt dissection, the number and the length of all the fascicles comprising the First Dorsal Interosseous (FDI) muscle and (2) to visually identify, via magnetic resonance imaging (MRI), the arrangement of the fascicles comprising the FDI. Simple blunt dissection of all the fascicles comprising four FDI muscles and their subsequent measurement demonstrated that the fascicles comprising the whole muscle were not as long as the muscle belly from which they were extracted. Muscle fascicles are surrounded by connective tissue hence the paths of the fascicles in two whole FDI muscles were identified via MRI by tracking the connective tissue surrounding the fascicles. The fascicles had a spiral pattern along the length of each muscle, within both muscles many of the fascicles were arranged in series with other fascicles. These architectural features of the fascicles of the FDI have important implications for the force–length and force–velocity properties of the whole muscle. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
The Prenatal Toxic Effect of Methylmercury on the Development of the Appendicular Skeleton of Rat Fetuses and the Protective Role of Vitamin E
Authors: Abd El‐Aziz Gamal S. , El‐Fark Magdy M.O. , Saleh Hamid A.M. 
Published: May 2012

AbstractMethylmercury (MeHg) is an environmental contaminant that is found in many ecosystems. Many studies reported that MeHg toxicity is accompanied by increased lipid peroxidation that may lead to oxidative damage to DNA, RNA, and proteins. Vitamin E is considered as the most effective antioxidant preventing lipid peroxidation. The aim of this study was to evaluate the effects of MeHg exposure during pregnancy on the development of the appendicular skeleton in rat fetuses and whether vitamin E administration could reduce this toxicity. Positively mated adult female Sprague–Dawley rats were used and divided into the following experimental groups: control group, received only deionized water, and four MeHg treated groups received 1 mg of MeHg/kg/d, 2 mg of MeHg/kg/d, 1 mg of MeHg/kg/d plus 150 mg of vitamin E/kg/d, and 2 mg of MeHg/kg/d, plus 150 mg of vitamin E/kg/d starting from Day 0 of gestation. On Day 20 of gestation, the fetuses from the pregnant rats were extracted and the fetal growth parameters were evaluated. Skeletal evaluation of ossification of both fore‐ and hind‐limbs, and coxal bones were undertaken. Results showed that treatment with MeHg caused adverse effects on fetal growth parameters and ossification of the bones. The coadministration of vitamin E with MeHg revealed an improvement in these parameters. These results suggest that vitamin E may ameliorate some aspects of MeHg developmental toxicity. The underlying and human health implications warrant further investigations. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Synthesis and Antimicrobial Evaluation of Novel Platensimycin Analogues
Authors: Plesch Eva , Bracher Franz , Krauss Jürgen 
Published: May 2012

AbstractSince the isolation of the natural products platensimycin and platencin as new antibiotic lead structures, several total syntheses as well as syntheses of derivatives have been developed. Most of these approaches are very laborious and the target molecules are often produced in only poor overall yields. The following approach describes the synthesis of rather simple platensimycin analogues focussing on some structure elements that have previously been identified as being essential for binding to the Fab F enzyme in fatty acid biosynthesis. Two of the new analogues show significant antimicrobial activities.
Adhesion molecule expression in human synovial tissue
Authors: Johnson Bruce A. , Haines George K. , Harlow Lisa A. , Koch Alisa E. 
Published: May 2012

AbstractObjective. We have previously shown that E‐selectin is expressed on endothelium in rheumatoid arthritis (RA) synovial tissues, and hence may be important in recruitment of leukocytes into the inflamed joint. In the present study, we determined whether other cellular adhesion molecules, including selectins and members of the integrin and immunoglobulin supergene families, are expressed in frozen synovium.Methods. We employed immunohistochemical staining to determine the distribution of CD31 (PECAM), CD44 (hyaluronate receptor), CD62 (P‐selectin), Leu‐8 (L‐selectin), and the integrin subunits α5 (VLA‐5), α6 (VLA‐6), β1 (VLA 1–6), and β3 (vitronectin receptor), in synovial tissue from 9 RA and 9 osteoarthritis (OA) patients, and from 3 normal (NL) subjects.Results. P‐selectin was expressed on vascular endothelium in all synovial tissues examined. L‐selectin and α5‐integrin, while expressed on a variety of cell types, were not differentially expressed on RA synovial tissues. Integrin subunits α6 and β1 were down‐regulated on some RA synovial tissue components. In contrast, CD31 was expressed to a greater extent on RA than on OA lining cells and macrophages (P < 0.05). CD44 was expressed to a greater extent on RA or OA macrophages, lining cells, and fibroblasts compared with NL (P < 0.05). Integrin subunit β3 was strongly expressed on RA synovial blood vessels compared with NL (P < 0.05).Conclusion. The expression of integrins VLA 1–6, and selectins P and L is not up‐regulated in RA synovial tissues. CD31 and CD44 are up‐regulated on RA macrophages and lining cells, CD44 on RA fibroblasts, and β3‐integrin on RA blood vessels. The up‐regulation of CD31, CD44, and β3‐integrin in RA synovial tissues may help tip the balance of adhesive interactions toward passage and retention of leukocytes in the inflamed joint.
Suppression of interleukin‐2 and interleukin‐2 receptor biosynthesis by gold compounds in in vitro activated human peripheral blood mononuclear cells
Authors: Sfikakis Peter P. , Souliotis Vassillis L. , Panayiotidis Panayiotis P. 
Published: May 2012

AbstractObjective. To further investigate the mechanism of action of gold compounds by studying their effects on interleukin‐2 (IL‐2) and IL‐2 receptor (IL‐2R) biosynthesis.Methods. We cultured phytohemagglutinin‐ or anti‐CD3 antibody‐activated normal peripheral blood mononuclear cells (PBMC), as well as the erythroleukemic K562 cell line, in the presence of gold sodium thiomalate or auranofin. Tritiated thymidine incorporation assays, cytotoxicity assays, immunofluorescence analysis, enzyme‐linked immunosorbent assay, Northern blot, and RNA dot‐blot hybridization were used.Results. Gold compounds, at concentrations attainable in vivo, inhibited the proliferation of normal PBMC, with no evidence of direct cytotoxicity. This inhibitory effect was associated with a dose‐dependent suppression of both IL‐2 and IL‐2R messenger RNA accumulation. In contrast, the same concentrations of gold compounds failed to inhibit the spontaneous proliferation of the IL‐2‐independent K562 cells.Conclusion. Our findings suggest an IL‐2/IL‐2R‐mediated mechanism for suppression of lymphocyte proliferation by gold compounds, which might account for the immunomodulatory effects of gold in patients with rheumatoid arthritis.
Divergent T cell receptor γ repertoires in rheumatoid arthritis monozygotic twins
Authors: Kohsaka Hitoshi , Chen Pojen P. , Taniguchi Atsuo , Ollier William E. R. , Carson Dennis A. 
Published: May 2012

AbstractObjective. To determine if the expressed T cell receptor (TCR) γ repertoire is altered in rheumatoid arthritis (RA).Methods. Peripheral blood lymphocytes were collected from monozygotic twins who were either concordant or discordant for RA, or from a normal twin pair. TCR γ‐specific complementary DNA libraries were constructed using the anchored polymerase chain reaction. Gene usage was analyzed by plaque hybridization and sequencing.Results. The expressed TCR VΓ repertoires both in RA patients and normal subjects were extremely diverse. Monozygotic twins who were concordant for RA expressed very different frequencies of TCR VΓ genes.Conclusion. RA does not lead to a specific clonal expansion or deletion of TCR VΓ genes in peripheral blood.
Bone mineral density of the hip and of the anteroposterior and lateral dimensions of the spine in men with rheumatoid arthritis: Effects of low‐dose corticosteroids
Authors: Garton Mark J. , Reid David M. 
Published: May 2012

AbstractObjective. To assess bone mineral density (BMD) in men with steroid‐treated rheumatoid arthritis (RA).Methods. Dual‐energy x‐ray absorptiometry (DXA) was used to measure BMD in 40 men with RA, 20 of whom were receiving low‐dose corticosteroids (≤10 mg prednisolone daily), and in 20 healthy, age‐matched male controls.Results. BMD was significantly reduced at the femoral neck and greater trochanter in both groups of RA patients, and at the spine from the anteroposterior dimension in the steroid‐treated group.Conclusion. Low‐dose steroid therapy may induce excess axial osteopenia in men with RA.
Induction of autoimmune arthritis in rats by immunization with homologous rat type II collagen is restricted to the RT1av1 haplotype
Authors: Griffiths Marie M. , Cannon Grant W. , Leonard Patrice A. , Reese Van R. 
Published: May 2012

AbstractObjective. To test for genetic differences in susceptibility to homologous (rat) type II collagen‐induced arthritis (RII‐CIA).Methods. Nine inbred and RT1‐congenic rat strains were immunized with native rat type II collagen and evaluated for arthritis and IgG anti‐RII serum antibody titers.Results. Only RT1av1 strains developed a high incidence of severe RII‐CIA and high titers of IgG anti‐RII serum antibody. Rats having RII‐CIA‐resistant haplotypes, RT1u,n,1 (which are known to develop CIA after immunization with heterologous type II collagen), were shown to also be susceptible to passive transfer of CIA with immune serum concentrates. Clinical expression of RII‐CIA was down‐regulated by non‐RT1 genes of BN origin. No strong gender differences in anti‐RII autoimmune responses were observed.Conclusion. Arthritogenic, autoimmune reactivity to homologous RII is under strict genetic control but occurs readily in RT1av1 rats.
Computed tomography findings of pulmonary venoocclusive disease in scleroderma patients presenting with precapillary pulmonary hypertension
Authors: Günther S. , Jaïs X. , Maitre S. , Bérezné A. , Dorfmüller P. , Seferian A. , Savale L. , Mercier O. , Fadel E. , Sitbon O. , Mouthon L. , Simonneau G. , Humbert M. , Montani D. 
Published: May 2012

AbstractObjectivePulmonary venoocclusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) characterized by obstruction of small pulmonary veins. Pulmonary venous involvement has been reported in pathologic assessment of patients with systemic sclerosis (SSc) presenting with precapillary PH. High‐resolution computed tomography (HRCT) of the chest is a noninvasive diagnostic tool used to screen for PVOD. No HRCT data are available on SSc patients with precapillary PH. We undertook this study to evaluate the frequency and effect on prognosis of HRCT signs of PVOD in SSc patients with precapillary PH.MethodsWe reviewed chest HRCT data from 26 SSc patients with precapillary PH and 28 SSc patients without pulmonary arterial hypertension (PAH) or interstitial lung disease (ILD).ResultsThe radiographic triad of HRCT signs of PVOD (lymph node enlargement [57.7% versus 3.6%], centrilobular ground‐glass opacities [46.2% versus 10.7%], and septal lines [88.5% versus 7.1%]) was significantly more frequent in SSc patients with precapillary PH than in SSc patients without PAH or ILD (all P < 0.005). Indeed, 61.5% of SSc patients with precapillary PH had ≥2 of these signs. Cardiomegaly (P < 0.0001), pulmonary artery enlargement (P < 0.0001), and pericardial effusion (P < 0.0005) were also significantly more frequent in SSc patients with precapillary PH. Pulmonary venous involvement was histologically confirmed in 2 patients with radiographic signs of PVOD. The presence of ≥2 radiographic signs of PVOD was associated with the occurrence of pulmonary edema after initiation of PAH‐specific therapy (in 8 of 16 patients) and with more rapid progression from diagnosis of PH to death.ConclusionHRCT signs of PVOD are frequently observed in SSc patients with precapillary PH, correlated with histologic assessment, and were associated with a high risk of pulmonary edema.
Yoga asanas as an effective form of experiential learning when teaching musculoskeletal anatomy of the lower limb
Authors: Bentley Danielle C. , Pang Stephen C. 
Published: May 2012

AbstractPhysical movement as a conduit for experiential learning within the academic context of anatomy is a strategy currently used in university dance education. This same approach can be applied to other movement‐based practices, for example, yoga. The primary purpose of this study was to pilot a novel teaching curriculum to yoga practitioners, based on Bruner's Theory of Instruction, which incorporated the four adaptive modes of Kolb's Theory of Experiential Learning. The secondary purpose was to assess the applicability of anatomical knowledge within the participants' yoga practice. Following the development of a curriculum appropriate for a spectrum of academic backgrounds, participants were recruited to attend a 2‐hour learning session within the Department of Anatomy at Queen's University in Kingston, Ontario, Canada. The learning session guided participants through the bones and muscles of the lower limb pertaining to five specific yoga poses. Based on participant feedback, the sessions were positively received and consistent. In addition, learning session participants were able to apply the anatomical information they were taught to their yoga practice 1‐month later. Bruner and Kolb's independent theories on curriculum design and effective learning practice were successfully incorporated to create a 2‐hour learning session. The potential use of experiential learning to compliment and/or enhance traditional didactic teaching in the academic context of anatomy should be further explored. Anat Sci Educ. © 2012 American Association of Anatomists.
Experimentelle Untersuchungen zur Ermüdung des Verbundes von Stahlbeton unter Querzug
Authors: Lindorf Alexander , Curbach Manfred 
Published: May 2012

AbstractEs wurde ein Versuchsprogramm durchgeführt, bei dem die Erforschung des Verbundverhaltens zwischen Bewehrungsstahl und Beton unter kombinierter Beanspruchung aus Ermüdung und Querzug mit Rissbildung im Mittelpunkt stand. Die Untersuchungen für normalfesten und hochfesten Beton erfolgten an Ausziehkörpern mit einem durch Querzug hervorgerufenen Längsriss entlang des Bewehrungsstabes. Die hochzyklischen Versuche mit bis zu einer Million Lastwechseln beinhalteten vier verschiedene Schwingspiele mit variierenden Längsrissbreiten. Für den Vergleich der einzelnen Belastungsbedingungen wurde das Schlupfwachstum zwischen Bewehrungsstab und Beton in Abhängigkeit von der Lastwechselzahl herangezogen. Im Ergebnis stellte sich der Einfluss des Querzuges auf den Verbundwiderstand unter schwellender Belastung deutlich heraus. Je breiter der Längsriss war, desto stärker wuchs der Schlupf und desto eher versagte der Verbund. Auf der Grundlage des Schlupfwachstums wurden Dauerfestigkeitsdiagramme für die Bemessung gegen Verbundermüdungsversagen abgeleitet.Experimental investigations on bond fatigue under transverse tensionAn experimental program was carried out, which focused on investigating the bond behaviour between reinforcing steel and concrete under combined loading due to fatigue and transverse tension. The investigations for both, normal strength concrete and high performance concrete were performed on pull‐out specimens with a longitudinal crack along the reinforcing bar due to transverse tension. High cyclic tests, of up to one million load cycles, were carried out for four different load levels with varying crack widths. The increase in slip between reinforcing steel bar and concrete relative to the number of load cycles was taken into account to compare various loading conditions. The influence of transverse tension on bond resistance under repeated loading became evident. The wider the longitudinal crack widths, the greater the increase in slip was and the earlier bond failure occurred. Based on slip development predictions, constant life diagrams were derived for fatigue design against bond fatigue failure.
A Selenium‐Based Click AdoMet Analogue for Versatile Substrate Labeling with Wild‐Type Protein Methyltransferases
Authors: Willnow Sophie , Martin Michael , Lüscher Bernhard , Weinhold Elmar 
Published: May 2012

AbstractProtein methylation is catalyzed by S‐adenosyl‐L‐methionine‐dependent protein methyltransferases (MTases), and this posttranslational modification serves diverse cellular functions. Some MTases seem to exhibit broad substrate specificities and comprehensive methods for target profiling are needed. Here we report the synthesis of a new AdoMet analogue for enzymatic transfer of a small propargyl group and labeling of modified proteins through copper‐catalyzed azide–alkyne cycloaddition (CuAAC). Replacement of sulfur by selenium strongly enhanced the stability of the progargylic cofactor, leading, in combination with better activation by the selenonium center, to higher enzymatic reactivity. A broad spectrum of wild‐type protein MTases acting on lysine, arginine, and glutamine residues accept this cofactor and modified substrates can be efficiently labeled by CuAAC click chemistry.
A completely fractured zotarolimus‐eluting stent in an aortocoronary saphenous vein bypass graft
Authors: Venero Carmelo V. , Aligeti Venkata R. , Wortham Dale C. 
Published: May 2012

AbstractDrug‐eluting stents (DES) have significantly improved the rate of target vessel revascularization in comparison with bare metal stents. DES fracture was not reported in multicenter randomized clinical trials, but several case reports of DES fracture have been published, mostly with sirolimus‐eluting stents. DES fracture is associated with stent restenosis and thrombosis. We report a zotarolimus‐eluting stent fracture in an aortocoronary saphenous vein graft (SVG) bypass. The patient presented with chest pain and a non‐ST‐elevation myocardial infarction. He underwent cardiac catheterization that showed a complete fracture of a zotarolimus‐eluting stent in the ostium of a sequential SVG to the diagonal and obtuse coronary arteries. His management included coronary angioplasty and retrieval of the proximal fractured segment. We discuss the potential causes for this stent fracture and suggest caution when using a DES in an ostial location of a SVG bypass, especially in a highly mobile vessel. © 2012 Wiley Periodicals, Inc.