bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oligodeoxynucleotide Containing S‐Functionalized 2′‐Deoxy‐6‐Thioguanosine: Facile Tools for Base‐Selective and Site‐Specific Internal Modification of RNA
Authors: Sasaki Shigeki , Onizuka Kazumitsu , Taniguchi Yosuke 
Published: March 2012

AbstractChemically modified oligonucleotides play a significant role for genomic research. Modified nucleosides, such as with a fluorescent dye, can be obtained by chemical synthesis. Site‐specifically modified long nucleic acids are obtained by ligation of chemically modified short oligonucleotides with enzyme, photochemistry, or catalytic DNA. The functionality‐transfer ODN (FT‐ODN), which contains 2′‐deoxy‐6‐thioguanosine (6‐thio‐dG) functionalized with the 2‐methyliden‐1,3‐diketone group, is hybridized with the target RNA to trigger the selective functionalization of the 4‐amino group of the cytosine base at pH 7 or the 2‐amino group of the guanine base at pH 9.4 or at pH 7.4 in the presence of NiCl2. In particular, the functionality‐transfer reaction (FTR) under the alkaline conditions or neutral conditions in the presence of NiCl2 proceeds rapidly and selectively to lead to the modification of the target guanine. The transfer reaction of the acetylene‐containing diketone group produces the acetylene‐modified RNA, which can be subjected to the Cu(I)‐catalyzed “click chemistry” with a variety of azide compounds for highly specific, internal modification of RNA. Curr. Protoc. Nucleic Acid Chem. 48:4.49.1‐4.49.16. © 2012 by John Wiley & Sons, Inc.
Synthesis of Dumbbell‐Shaped Cyclic RNAs for RNA Interference
Authors: Abe Naoko , Abe Hiroshi , Ito Yoshihiro 
Published: March 2012

AbstractRNA interference (RNAi) is a potent and highly specific gene‐silencing phenomenon that was first reported for the nematode Caenorhabditis elegans. It has been discovered that genes could be silenced by introducing double‐stranded RNAs (dsRNAs) complementary to the messenger RNA sequences. Since then, RNAi has been shown as an evolutionarily well‐conserved process that plays an important role in host defense and in regulation of gene expression. Much effort has been dedicated to the application of the short dsRNA species (short interfering RNAs; siRNAs) as therapeutic agents, as they were shown to be effective in mammalian cells. Recently, we altered the structure of a siRNA molecule and produced dumbbell‐shaped nanocircular RNAs. RNA dumbbells were shown to be stabilized in serum compared with its siRNA counterpart, despite their natural RNA strand. It has also been found that RNA dumbbells containing a 23‐bp stem and two 9‐nt loops exhibit a prolonged RNAi effect in cultured mammalian cells. In this unit, we describe the synthesis of RNA dumbbells from the design, its enzymatic synthesis, and to the purification. Curr. Protoc. Nucleic Acid Chem. 48:16.4.1‐16.4.11. © 2012 by John Wiley & Sons, Inc.
Rheumatologists' quality of care for lupus: Comparison study between a university and county hospital
Authors: Dua Anisha B. , Aggarwal Rohit , Mikolaitis Rachel A. , Sequeira Winston , Block Joel A. , Jolly Meenakshi 
Published: March 2012

AbstractObjectiveQuality of care received from physicians may impact health outcomes in systemic lupus erythematosus (SLE). We compared physician quality of care (P‐QOC), health‐related quality of life (HRQOL), and disease activity and damage between SLE patients receiving outpatient care at a university and a county rheumatology clinic.MethodsForty‐two university and 41 county clinic SLE patients provided data on 5 P‐QOC parameters and HRQOL health outcomes (Short Form 36 [SF‐36] health survey and EuroQol 5‐domain instrument [EQ‐5D]). Disease activity and damage were measured. Chi‐square analysis and Student's t‐tests were used for comparisons.ResultsOverall satisfaction with medical care was similar; however, university patients had higher P‐QOC scores than county patients in “perception of doctor's understanding of impact of SLE on patient's life” (P = 0.02) and “providing education/educational information to understand their disease” (P = 0.05). HRQOL, disease activity, and damage were similar in the 2 groups. Overall satisfaction with medical care was directly related SF‐36 general health (r = 0.34, P = 0.03) and EQ‐5D visual analog scale on state of health (r = 0.39, P = 0.01), and inversely related EQ‐5D pain (r = −0.37, P = 0.02).ConclusionPatient perceptions of P‐QOC differed across the 2 centers despite similar demographics, clinical and HRQOL outcomes, and significant overlap in the physicians serving each clinic. Patients' overall satisfaction with medical care is associated with better HRQOL.
Association of slower walking speed with incident knee osteoarthritis–related outcomes
Authors: Purser Jama L. , Golightly Yvonne M. , Feng Qiushi , Helmick Charles G. , Renner Jordan B. , Jordan Joanne M. 
Published: March 2012

AbstractObjectiveTo determine whether slower walking speed was associated with an increased risk of incident hip and knee osteoarthritis (OA)–related outcomes.MethodsAfter providing informed consent, community‐dwelling participants in the Johnston County Osteoarthritis Project completed 2 home‐based interviews and an additional clinic visit for radiographic and physical evaluation. One thousand eight hundred fifty‐eight noninstitutionalized residents ages ≥45 years living for at least 1 year in 1 of 6 townships in Johnston County, North Carolina, completed the study's questionnaires and clinical examinations at baseline and at followup testing. Walking time was assessed using a manual stopwatch in 2 trials over an 8‐foot distance, and walking speed was calculated as the average of both trials. For the hip and knee, we examined 3 outcomes per joint site: radiographic OA (weight‐bearing anteroposterior knee radiographs, supine anteroposterior pelvic radiographs of the hip), chronic joint symptoms, and symptomatic OA. Covariates included age, sex, race, education, marital status, body mass index, number of self‐reported chronic conditions diagnosed by a health care provider, number of prescriptions, depressive symptoms, self‐rated health, number of lower body functional limitations, smoking, and physical activity.ResultsFaster walking speed was consistently associated with a lower incidence of radiographic (adjusted odds ratio [OR] 0.88, 95% confidence interval [95% CI] 0.79–0.97) and symptomatic knee OA (adjusted OR 0.84, 95% CI 0.75–0.95); slower walking speed was associated with a greater incidence of these outcomes across a broad range of different clinical and radiographic OA outcomes.ConclusionSlower walking speed may be a marker for incident knee OA, but other studies must confirm this finding.
Effects of the Molecular Weight and the Side‐Chain Length on the Photovoltaic Performance of Dithienosilole/Thienopyrrolodione Copolymers
Authors: Chu Ta‐Ya , Lu Jianping , Beaupré Serge , Zhang Yanguang , Pouliot Jean‐Rémi , Zhou Jiayun , Najari Ahmed , Leclerc Mario , Tao Ye 
Published: March 2012

AbstractA series of low‐bandgap alternating copolymers of dithienosilole and thienopyrrolodione (PDTSTPDs) are prepared to investigate the effects of the polymer molecular weight and the alkyl chain length of the thienopyrrole‐4,6‐dione (TPD) unit on the photovoltaic performance. High‐molecular‐weight PDTSTPD leads to a higher hole mobility, lower device series resistance, a larger fill factor, and a higher photocurrent in PDTSTPD:[6,6]‐phenyl C71 butyric acid methyl ester (PC71BM) bulk‐heterojunction solar cells. Different side‐chain lengths show a significant impact on the interchain packing between polymers and affect the blend film morphology due to different solubilities. A high power conversion efficiency of 7.5% is achieved for a solar cell with a 1.0 cm2 active area, along with a maximum external quantum efficiency (EQE) of 63% in the red region.
Routes to carboxylic acid functional acrylonitrile copolymers via N‐tert‐butyl‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl) free nitroxide based nitroxide‐mediated polymerization
Authors: Consolante Valerie , Maric Milan , Penlidis Alexander 
Published: March 2012

AbstractStyrene (S)/acrylonitrile [AN; initial acrylonitrile molar feed compositions (fAN,0's) = 0.10–0.86) and tert‐butyl methacrylate (tBMA)/AN (fAN,0 = 0.10–0.80) copolymers were synthesized at 90°C in 50 wt % 1,4‐dioxane solutions with a unimolecular initiator, N‐(2‐methylpropyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐O‐(2‐carboxylprop‐2‐yl) hydroxylamine [BlocBuilder (BB)]. In the tBMA/AN copolymerizations, 8.0–8.5 mol % N‐tert‐butyl‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl) free nitroxide relative to BB was added. The S/AN copolymers exhibited narrow, monomodal molecular weight distributions (MWDs) with low polydispersities [weight‐average molecular weight (Mw)/number‐average molecular weight (Mn) = 1.14–1.26], and the Mn versus monomer conversion (X) plots were relatively linear (Mn = 18.1 kg/mol, X ≈ 0.7); this suggested that pseudo‐living behavior was approached. AN proved to be an effective controlling comonomer for tBMA because the tBMA/AN copolymers exhibited narrow monomodal MWDs with Mw/Mn = 1.17–1.50 and relatively linear Mn versus X plots to reasonably high X values (Mn = 15.6 kg/mol, X ≈ 0.6). The AN and S monomer reactivity ratios were rAN = 0.07 ± 0.01 and rS = 0.27 ± 0.02 (Fineman–Ross) and rAN = 0.10 ± 0.01 and rS = 0.28 ± 0.02 (Kelen–Tüdos), respectively; these values were in good agreement with conventional free‐radical polymerization. Error‐in‐variables model (EVM) analysis indicated that the use of cumulative composition S/AN data was more effective than typical approaches using low‐X data with the Mayo–Lewis model. The AN and tBMA reactivity ratios [rAN = 0.07 ± 0.01 and rtBMA = 1.24 ± 0.20 (Fineman–Ross) and rAN = 0.14 ± 0.01 and rtBMA = 0.89 ± 0.19 (Kelen–Tüdos)] were similar to those reported for related alkyl methacrylate/AN conventional radical copolymerizations. EVM analysis suggested significant experimental error was associated with the tBMA/AN system, and this warrants further investigation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of predetermined nuclei and limited transformation on polymorphic crystallization in a model polymer
Authors: Misztal‐Faraj Beata , Ziabicki Andrzej 
Published: March 2012

AbstractFormation of different polymorphic structures plays important role in crystallization of some polymers, like polypropylene, polycaproamide, poly(vinylidene difluoride), and others. Physical properties of such materials depend on phase structure, that is, fractions of different polymorphs. Basing on the model of many‐phase transitions (Ziabicki, J Chem Phys 2005, 123, 174103; Ziabicki and Misztal‐Faraj, J Mater Res, 2011, 26, 1585) a model system consisting of an amorphous phase, stable solid phase, and metastable polymorphic phase was analyzed. Two effects in the kinetics of polymorphic crystallization have been analyzed: effect of the presence of universal and/or selective predetermined nuclei and limited crystallizability resulting from molecular constraints in high‐molecular systems. Conditions in which different phase compositions (i.e., different proportions of individual phases) have been discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New constitutive modeling for time‐dependent mechanical behavior of polymers close to glass transition: Fundamentals and experimental validation
Authors: Billon Noëlle 
Published: March 2012

AbstractThe 1D limit of a 3D visco‐hyperelastic model is discussed and validated using a rich and rigorous database obtained on PMMA above Tg. Inelastic phenomena are accounted for as an evolution of internal variables assumed to be related to the alteration of microstructure that induces changes in well chosen constitutive parameters and dissipation of energy. Inelastic strain‐rate is deduced from energy balance between elastic and dissipative phenomenon. The concept allows introducing time effects in any rubber elasticity theory, resulting in a visco‐hyperelastic model consistent with continuum thermodynamics. In this article, Edwards‐Vilgis' model is used as the core and extended to a general time dependent constitutive model. Phenomenological models for disentanglement or crystallization are suggested that allow reproducing all viscoelastic effects using one unique model. An accounting for temperature and strain‐rate effects by an “a priori” uses of time temperature superposition principle is also proposed. The three concepts result in an original model of high efficiency. This new approach is a highly attractive way of modeling time dependent behavior of polymers over a wide range of temperature and strain‐rate up to large strains. This is demonstrated in the case of PMMA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and properties of extruded thermoplastic starch/polymer blends
Authors: Huneault Michel A. , Li Hongbo 
Published: March 2012

AbstractThis article examines the starch gelatinization and the blend morphology development in blends of thermoplastic starch (TPS) with high‐density polyethylene, polypropylene, polystyrene, poly(lactic acid), and polycaprolactone. The TPS gelatinization and mixing with the second polymer was carried out on a twin‐screw extrusion process, where the starch was sequentially gelatinized, devolatilized, and then mixed in the molten state with a synthetic polymer. The role of excess water and process temperature on starch gelatinization was assessed by measuring the X‐ray scattering. All prepared blends included 25 % TPS that was dispersed in the synthetic polymer matrix. Compatibilized versions of these same blends were obtained by partially substituting the polymer matrices with maleated analogs. The blend morphology was probed by scanning electron microscopy. Complete starch gelatinization was obtained when the gelatinization process was carried out over 100°C regardless of amount of water used as co‐plasticizer. The blend morphologies were greatly improved when a maleated compatibilizer was added. Only TPS/PCL blends exhibited a finely dispersed TPS phase without the use of a compatibilizer. In general, the addition of the TPS reduced slightly the tensile modulus and strength of the different polymers and more importantly the elongation at break. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Micronization of polyethylene terephthalate via freezing of highly sheared emulsions of polyethylene terephthalate in saturated liquid tetrahydrofuran
Authors: Tapriyal D. , Fan X. , Heintz Y. , Morsi B. , Beckman E. , Enick R. , Sane A. , Thies M. , Schutte G. , Niederst J. 
Published: March 2012

AbstractA novel technique for micronizing polyethylene terephthalate (PET) resin (∼ 3 mm) with saturated liquid tetrahydrofuran (THF) has been developed. PET pellets were introduced to a high‐pressure vessel filled halfway with THF at loadings up to ∼ 7 wt % PET. When the vessel was closed and heated, the PET pellets exhibited significant melting point depression at 190°C in saturated liquid THF at 17.1 bar. Although other organic solvents were also able to depress the melting point of PET, only THF was able to facilitate the formation of an emulsion of PET‐rich liquid droplets in the saturated liquid solvent when the mixture was agitated. In an attempt to generate the smallest possible PET droplets, a high‐speed (5000 rpm), close‐clearance, radial flow impeller was used to shear and disperse the droplets at ∼ 200°C and 20.1 bar. Emulsion was rapidly cooled while mixing. The PET droplets froze at ∼ 190°C, and the vessel was then cooled to ambient temperature. The excess liquid THF was decanted, and the PET particles were dried in a vacuum oven to remove residual THF. The PET particle sizes ranged between 2 and 70 μm, with number, area, and volume average diameters of 6, 20, and 30 μm, respectively. A comparison between the PET resin and PET powder properties indicated that the micronization reduced the Mw from 32,700 to 22,800. DSC results suggest that the rapid quench leads to a morphology different from equilibrium, with small somewhat imperfect crystallites, a lower overall degree of crystallinity, and a suppressed ΔCp at the glass transition. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and solution properties of an associative polymer with excellent salt‐thickening
Authors: Zhong Chuanrong , Wang Wei , Yang Mingming 
Published: March 2012

AbstractTo enhance apparent viscosities in brine solutions with high salinities for associative water‐soluble polymers, a novel macromonomer (APEO): allyl‐capped octylphenoxy poly(ethylene oxide) (degree of polymerization: 14) was synthesized, and a novel tetra‐polymer (PAVO) was synthesized by copolymerizing APEO, acrylamide (AM), sodium 2‐acrylamido‐2‐methylpropane sulfonate (NaAMPS), and vinyl biphenyl (VP). The macromonomer and the PAVO polymer were characterized with Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H‐NMR). The apparent viscosities of PAVO in pure water were very low over all polymer concentrations, and the critical association concentration (C*p) was 0.15 g dL−1. However, in brine solutions above 40 g L−1 NaCl or 10 g L−1 CaCl2, the intermolecular hydrophobic associations of octylphenyl groups and biphenyl groups were enhanced dramatically, the polymer chains were still comparatively extended due to the incorporation of APEO into the polymer, C*p was reduced to 0.10 g dL−1, and the apparent viscosities were significantly higher than in pure water. The PAVO brine solutions exhibited excellent salt‐thickening induced by metallic univalent or bivalent cations, heat‐thickening effect, shear‐thickening behavior, and thixotropy. Moreover, the brine solution also performed good resistance to ageing because of the simultaneous incorporation of bulky side groups. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical and rheological properties, and morphology of polyamide‐6/organoclay/elastomer nanocomposites
Authors: Isik‐Gulsac Isil , Yilmazer Ulku , Bayram Goknur 
Published: March 2012

AbstractThe effects of ethylene‐methyl acrylate‐glycidyl methacrylate (E‐MA‐GMA) terpolymer and three types of organoclays (Cloisite® 15A, 25A, and 30B) on mechanical and rheological properties, and morphology of impact modified polyamide‐6/montmorillonite ternary nanocomposites were investigated by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), parallel disk rheometry, melt flow index measurements, and tensile and impact tests. The materials were prepared by melt blending using a co‐rotating twin‐screw extruder. XRD and TEM analyses showed that exfoliated‐intercalated nanocomposites were formed in both polyamide‐6/Cloisite® 25A and Cloisite® 30B binary nanocomposites and in ternary systems. SEM micrographs showed that rubber domain sizes were larger in the nanocomposites than in their corresponding polyamide‐6/elastomer blends. Generally, tensile strength, Young's modulus, and elongation at break decreased with the addition of elastomer to polyamide‐6/organoclay binary nanocomposites. In the melt state, liquid‐like behavior of polyamide‐6 slightly turned to pseudo solid‐like in the binary and ternary nanocomposites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Intervertebral disc and macrophage interaction induces mechanical hyperalgesia and cytokine production in a herniated disc model in rats
Authors: Takada Toru , Nishida Kotaro , Maeno Koichiro , Kakutani Kenichiro , Yurube Takashi , Doita Minoru , Kurosaka Masahiro 
Published: March 2012

AbstractObjectiveThe expression of proinflammatory factors such as tumor necrosis factor α (TNFα), interleukin‐6 (IL‐6), IL‐8, and prostaglandin E2 (PGE2) is significantly correlated with the symptoms of herniated disc disease. Among the different types of immune cells, macrophages are frequently noted in the herniated disc tissue. We undertook this study to clarify the interaction of the intervertebral disc (IVD) and macrophages with regard to the production of TNFα, IL‐6, IL‐8, and PGE2.MethodsWe developed 2 animal models to assess the interactions of IVDs with macrophages in terms of TNFα, IL‐6, IL‐8, and PGE2 production and pain‐related behavior. We also cocultured IVDs and macrophages to assess the role of TNFα in IL‐6, IL‐8, and PGE2 production.ResultsIVD autografts induced TNFα, IL‐6, IL‐8, and cyclooxygenase 2 (COX‐2) messenger RNA (mRNA) up‐regulation; macrophage infiltration was seen shortly after the autograft was implanted. A significant decrease was noted in the mechanical threshold of the ipsilateral paw following the up‐regulation of TNFα, IL‐6, IL‐8, and COX‐2 mRNA. Only IVD and macrophage cocultures resulted in IL‐8 and PGE2 up‐regulation. TNFα up‐regulation was maximized before that of IL‐6 and IL‐8. TNFα neutralization attenuated production of IL‐6 and PGE2, but not that of IL‐8. Neutralization of TNFα and IL‐8 significantly increased the paw withdrawal mechanical threshold in the IVD autograft and spinal nerve ligation model.ConclusionIVD–macrophage interaction plays a major role in sciatica and in the production of TNFα, IL‐6, IL‐8, and PGE2. TNFα is required for IL‐6 and PGE2 production, but not for IL‐8 production, during IVD–macrophage interaction. Neutralization of TNFα and IL‐8 can be a valuable therapy for herniated disc disease.
Multifunctional T cell reactivity with native and glycosylated type II collagen in rheumatoid arthritis
Authors: Snir Omri , Bäcklund Johan , Boström Julia , Andersson Ida , Kihlberg Jan , Buckner Jane H. , Klareskog Lars , Holmdahl Rikard , Malmström Vivianne 
Published: March 2012

AbstractObjectiveType II collagen (CII) is a cartilage‐specific protein to which a loss of immune tolerance may trigger autoimmune reactions and cause arthritis. The major T cell epitope on CII, amino acids 259–273, can be presented by several HLA–DRB1*04 alleles in its native or posttranslational glycosylated form. The present study was undertaken to functionally explore and compare CII‐autoreactive T cells from blood and synovial fluid of patients with rheumatoid arthritis (RA).MethodsPeripheral blood was obtained from HLA–DRB1*04–positive RA patients (n = 10) and control subjects (n = 10) and stimulated in vitro with several variants of the CII259–273 epitope, i.e., unmodified, glycosylated on Lys‐264, glycosylated on Lys‐270, or glycosylated on both Lys‐264 and Lys‐270. Up‐regulation of CD154 was used to identify responding T cells. These cells were further characterized by intracellular staining for interleukin‐17 (IL‐17), interferon‐γ (IFNγ), and IL‐2 by flow cytometry. Synovial T cells from RA patients were investigated in parallel.ResultsMultifunctional T cell responses toward all examined variants of the CII259–273 peptide could be detected in RA patients and, to a lesser extent, also in healthy HLA‐matched controls (P < 0.001). In RA patients, a comparison between blood‐ and joint‐derived T cell function revealed a significant increase in levels of the proinflammatory cytokine IFNγ in synovial T cells (P = 0.027). Studies of longitudinally obtained samples showed that T cell responses were sustained over the course of disease, and even included epitope spreading.ConclusionThe identification of inflammatory T cell responses to both glycosylated and nonglycosylated variants of the major CII epitope in RA patients suggests that CII autoreactivity in RA may be more common than previously recognized.