bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Drying of Poly(N‐isoproplacrylamide‐co‐acrylamide) by Fluorescence Technique
Authors: EvingüR Gülşen Akin , Pekcan Önder 
Published: April 2012

AbstractThe steady‐state fluorescence technique was performed on drying of various molar percentages of poly(N‐isopropylacrylamide‐co‐ acrylamide) [poly(NIPA‐co‐AAc)] to elucidate the mechanism of temperature‐induced phase separation and the effect of monomer content. Poly(NIPA‐co‐AAc) copolymers were prepared by free radical cross‐linking copolymerization. The fluorescence intensity, I, of pyranine, introduced as a probe, increased as drying time was increased for all samples. The behavior of I was modeled by using the Stern–Volmer equation combined with the moving boundary diffusion model. The desorption coefficient, D, increased as NIPA content was increased at a given temperature. Gravimetric and volumetric experiments also supported the results of the fluorescence technique. The energy, Δ E, values were measured for the drying processes for each molar percentage of NIPA monomer content by using fluorescence, gravimetric, and volumetric methods, respectively. It is understood that Δ E values decrease by increasing NIPA content, until 50% NIPA, and then increase after 50% NIPA, indicating that the phase separation has occurred at 50% NIPA. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E231–E240, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21269
On the Pinning of Downstream Meniscus for Slot Die Coating
Authors: Lin Chi‐Feng , Wang Bo‐Kai , Tiu Carlos , Liu Ta‐Jo 
Published: April 2012

AbstractThe pinning behavior of the downstream contact line between the coating bead and coating die corner for slot die coating was studied. For uniform coating, the downstream contact line must not go beyond the die corner; otherwise, an undesirable vortex may appear near the downstream meniscus. The locations of the upstream and the downstream menisci were computed by the commercial software package FLOW‐3D®, and the theoretical predictions were verified by flow visualization experiments. Three possible approaches in die design were investigated to ensure the downstream meniscus remains in constant contact with the die surface. These were (1) reducing the angle between the slot die shoulder and the die lip, (2) increasing the lyophobicity of the die surface, and (3) raising the coating gap between the die lip and the substrate. The first method was found to be the most effective, as it also increases the maximum coating speed. The second method was feasible only if proper surface modification is applied. The third method potentially caused the creation of a new vortex under the die lip. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E249–E257, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21271
Preparation of polyaniline coated polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) microparticles and the further fabrication of hollow polyaniline microspheres
Authors: Sun Libo , Shi Yuanchang , Chu Linya , Xu Xiaokuai , Liu Jiurong 
Published: April 2012

AbstractIn this article, the microparticles of polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) (PS‐PSS) coated by polyaniline (PANI) were prepared and hollow PANI microspheres were further obtained by dissolving the core. First, surface‐sulfonated monodispersed PS was prepared by copolymerization of sodium 4‐styrenesulfonate (SSS) and styrene with dispersion polymerization method. Then aniline was polymerized on the surface of the surface‐sulfonated PS (PS‐PSS) by chemical oxidative polymerization. After purification, we prepared core‐shell (PS‐PSS)/PANI particles. Hollow PANI microspheres were prepared by dissolving the plastic PS core of the (PS‐PSS)/PANI particles in chloroform. The growth process of PANI on the surface of PS‐PSS particles was investigated and the hollow PANI microspheres were characterized. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polypyrrole–multiwalled carbon nanotubes composites as immobilizing matrices of ascorbate oxidase for the facile fabrication of an amperometric vitamin C biosensor
Authors: Li Dong , Wen Yangping , He Haohua , Xu Jingkun , Liu Ming , Yue Ruirui 
Published: April 2012

AbstractAn amperometric vitamin C biosensor was facilely fabricated by the immobilization of ascorbate oxidase (AO) on polypyrrole (PPy)–multiwalled carbon nanotubes (MWCNTs) composites with a one‐step electrodeposition technique in a 0.05M phosphate buffer solution (pH 6.5). The cyclic voltammetry, IR spectral analysis, electrochemical impedance spectroscopy, and scanning electron microscopy measurements indicated that AO was successfully immobilized on the PPy–MWCNT composites. The optimization of the biosensor parameters, including the working potential, pH, and temperature, was investigated in detail. The proposed biosensor showed a linear range of 5 × 10−5 to 2 × 10−2
M with a detection limit of 0.3 μM, a sensitivity of 25.9 mA mM−1 cm−2, and a current response time less than 20 s under the optimized conditions. The apparent Michaelis–Menten constant together with the apparent activation energy indicated that the proposed biosensor exhibited a high bioaffinity and a good enzyme activity. In addition, the biosensor also showed good operational and storage stabilities. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polymer‐modified bitumen of recycled LDPE and maleated bitumen
Authors: Singh B. , Kumar Lokesh , Gupta M. , Chauhan G. S. 
Published: April 2012

AbstractMaleated bitumen was prepared by the reaction of penetration grade bitumen (80/100) with maleic anhydride at 150°C for 2 h under nitrogen atmosphere. The effectiveness of maleation was assessed in bitumen–recycled low‐density polyethylene (LDPE) blends in terms of their softening point and elastic recovery. It was observed that the softening point and elastic recovery of the blends increased after maleation of the base bitumen owing to the formation of an asphaltene‐linked‐LDPE system. To obtain the desired elasticity, a recoverable composition was worked out with the help of maleated bitumen, recycled LDPE and styrene–butadiene–styrene. The storage stability of the blends was assessed in terms of their difference in softening points, rheological parameters, and microstructure of the top and bottom portions of test tube samples. The difference in softening point of the recoverable maleated bitumen blend was 5°C as compared to 60°C for the base bitumen blend. The phase angle was also reduced to 7.4° at 70°C compared with the 44.30° for the base bitumen blend. Scanning electron micrographs indicate that polymers existed in both the top and the bottom portions of the aged test tube maleated blend samples. The stability of the blend was further improved when LDPE is colloidal milled with maleic anhydride in the blend preparation. Roofing bitumen was also made with maleated bitumen containing 9 wt % recycled LDPE content. Based on the rheological data, it was found that the maleated bitumen–LDPE blend exhibited superior time‐/temperature‐dependent response and higher creep recovery compared with the base bitumen blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Void ratio and durability properties of porous polymer concrete using recycled aggregate with binder contents for permeability pavement
Authors: Sung Chan‐Yong , Kim Young‐Ik 
Published: April 2012

AbstractParticularly in Korea, where most roads are paved with impermeable materials such as asphalt and cement concrete, problems arise such as increased flooding as result of rainwater flowing into urban streams and the depletion of underground water. In recent years, there has been a great deal of ongoing research concerning water permeability and drainage in pavements. Accordingly, in this research, a porous polymer concrete was developed by using unsaturated polyester resin as a binder, recycled aggregate as coarse aggregate, fly ash and blast‐furnace slag as filler for permeable pavement, and its physical and mechanical properties were investigated. Regardless of the type of filler and amount of binder, the standard void ratio of 8% specified in the mixture of permeable asphalt was exceeded. In all mixes, regardless of the type of filler and amount of binder, the standard compressive strength for permeable concrete of 18 MPa was exceeded. Also, in all mixes, the standard permeability coefficient of 1.0 × 10−2 cm/s for permeable asphalt mixture was exceeded. The weight reduction ratio of the porous polymer concrete that was submerged in 10% sulfuric acid solution was 1.17 to 2.3%, and it was found that there was virtually no weight reduction. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Structural differences between wood species: Evidence from chemical composition, FTIR spectroscopy, and thermogravimetric analysis
Authors: Poletto Matheus , Zattera Ademir J. , Santana Ruth M. C. 
Published: April 2012

AbstractIn this study, the relationship between wood cellulose crystallinity, influence of extractives on wood degradation, correlation between chemical composition, and physical properties of four wood species were investigated by chemical analysis, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry. The chemical analysis showed that Dipteryx odorata and Mezilaurus itauba (ITA) contained a higher quantity of extractives and lower quantities of holocellulose and lignin than Eucalyptus
grandis (EUG) and Pinus elliottii. FTIR spectroscopy indicated that higher extractives content in ITA might be associated with more intense bands at 2920, 2850, and 1510 cm−1. The lower values for hydrogen bond energy and hydrogen bond intensity showed that EUG contained more absorbed water than the other species. Thermogravimetry confirm that lower extractive contents leads to a better wood thermal stability. This study showed that through the methods used previous information about structure and properties of wood can be obtained before use it in composite formulations. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation of optical and thermally stimulated properties of SiO2 nanoparticles‐filled polycarbonate
Authors: Rathore Bhupendra Singh , Gaur Mulayam Singh , Singh Kripa Shanker 
Published: April 2012

AbstractPolycarbonate nanocomposite containing silicon oxide nanoparticles average size of 5 nm at different weight ratio has been prepared by solution mixing method. The dispersion of nanoparticles in polymer matrix was studied by transmission electron microscopy (TEM). The optical and thermally stimulated behavior of nanocomposites were analyzed by energy dispersive X‐ray spectra (EDX), X‐ray diffraction pattern (XRD), UV–vis spectroscopy, differential scanning calorimetry (DSC), and thermally stimulated discharge current (TSDC). TEM images show the dispersion and size of the nanoparticles, however, EDX indicate the presence of SiO2 on the surface of the nanocomposite film. An XRD result reveals that the crystallinity increases with increase in concentration of SiO2 nanoparticles in polymer matrix. The direct and indirect optical energy band gaps decreased and number of carbon atom increased with concentration of SiO2 nanoparticles. We have observed that the increase of SiO2 nanoparticles in PC significantly reduces the refractive index. DSC and TSDC show that glass transition temperature increases according to SiO2 weight ratio. The TSDC of nanocomposites samples could be understand in terms of non‐Debye theory of charge relaxation and co‐tunneling mechanism of charge transport. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Automated selection and harvesting of pluripotent stem cell colonies
Authors: Haupt Simone , Grützner Jan , Thier Marc‐Christian , Kallweit Tobias , Rath Barbara Helen , Laufenberg Iris , Forgber Michael , Eberhardt Jens , Edenhofer Frank , Brüstle Oliver 
Published: April 2012

AbstractThe ability of pluripotent stem cells to differentiate into specialized cells of all three germ layers, their capability to self‐renew, and their amenability to genetic modification provide fascinating prospects for the generation of cell lines for biomedical applications. Therefore, stem cells must increasingly suffice in terms of industrial standards, and automation of critical or time‐consuming steps becomes a fundamental prerequisite for their routine application. Cumbersome manual picking of individual stem cell colonies still represents the most frequently used method for passaging or derivation of clonal stem cell lines. Here, we explore an automated harvesting system (CellCelector™) for detection, isolation, and propagation of human embryonic stem cells (hESCs) and murine induced pluripotent stem cells (iPSCs). Automatically transferred hESC colonies maintained their specific biological characteristics even after repeated passaging. We also selected and harvested primary iPSCs derived from mouse embryonic fibroblasts expressing the green fluorescent protein (GFP) under the control of the Oct4 promotor using either morphological criteria or GFP fluorescence. About 80% of the selected and harvested primary iPSC colonies gave rise to homogenously GFP‐expressing iPSC lines. To validate the iPSC lines, we analyzed the expression of pluripotency‐associated markers and multi‐germ layer differentiation potential in vitro. Our data indicate that the CellCelector™ technology enables efficient identification and isolation of pluripotent stem cell colonies at the phase contrast or fluorescence level.
Genetically engineered stem cell‐based strategies for articular cartilage regeneration
Authors: Santhagunam Aruna , Madeira Catarina , Cabral Joaquim M. S. 
Published: April 2012

AbstractCartilage is frequently injured, often as a result of inflammatory rheumatic diseases or sports‐related trauma. Given its nonvascular nature, articular cartilage has a limited capability for self‐repair and currently the few therapeutic options still have uncertain long‐term outcomes. Cell‐based surgical therapies using autologous chondrocytes to repair cartilage injury have been used in the clinic for over a decade, but this approach has shown mixed results mainly due to the low number of harvested chondrocytes and the loss of cartilage‐related phenotype and functionality after several passages of in vitro culture. A wide range of cell sources have been tested to circumvent chondrocyte limitations in cartilage repair, and stem cells have been presented as those that offer the greatest potential for clinical application. This review will focus on recent advances in stem cell‐based strategies for articular cartilage repair, specifically focusing on the use of genetically engineered adult stem cells by conventional gene delivery methods and by gene‐activated matrices. Perspectives in cartilage engineering are also addressed.
Procyanidins and inflammation: Molecular targets and health implications
Authors: Martinez‐Micaelo Neus , González‐Abuín Noemi , Ardèvol Anna , Pinent Montserrat , Blay Maria Teresa 
Published: April 2012

AbstractThe inflammatory response has been implicated in the pathogenesis of many chronic diseases. Thus, the modulation of the inflammatory response by the consumption of bioactive food compounds, such as procyanidins, is a powerful tool to promote health. Procyanidin‐mediated anti‐inflammatory molecular mechanisms include, among others, the modulation of the arachidonic acid pathway, the inhibition of the gene transcription, protein expression and enzymatic activity of eicosanoid generating enzymes, the production and secretion of inflammatory mediators (such as cytokines and nitric oxide), the inhibition of mitogen‐activated protein kinase (MAPK) pathway activation, and the modulation of the nuclear factor‐κB (NF‐κB) pathway. The NF‐κB pathway can be regulated by procyanidins at several levels. During early events in NF‐κB signaling, procyanidins modulate Iκκ activity, and the cytoplasmic retention of p65:p50 NF‐κB by the inhibition of IκB phosphorylation and proteasomal degradation, while at late stages, they affect the nuclear translocation of pro/anti‐inflammatory NF‐κB homo/hetero dimers and their subsequent binding to the promoter regions of target genes. To identify and understand the value of procyanidins in the modulation of the inflammatory response, the molecular mechanisms underlying the anti‐inflammatory activities and prohomeostatic effects of procyanidins need to be investigated further. © 2012 International Union of Biochemistry and Molecular Biology, Inc.
Microglial physiopathology: how to explain the dual role of microglia after acute neural disorders?
Authors: Gomes‐Leal Walace 
Published: April 2012

AbstractMicroglia are the resident macrophages of the central nervous system (CNS). In physiological conditions, resting microglia maintain tissue integrity by scanning the entire CNS parenchyma through stochastic and complex movements of their long processes to identify minor tissue alterations. In pathological conditions, over‐activated microglia contribute to neuronal damage by releasing harmful substances, including inflammatory cytokines, reactive oxygen species, and proteinases, but they can provide tissue repair by releasing anti‐inflammatory cytokines and neurotrophic factors. The reasons for this apparent paradox are unknown. In this paper, we first review the physiological role as well as both detrimental and beneficial actions of microglial during acute CNS disorders. Further, we discuss the possible reasons for this microglial dual role following CNS insults, considering that the final microglial phenotype is a direct consequence of both noxious and beneficial stimuli released into the extracellular space during the pathological insult. The nature of these micro‐glial ligands is unknown, but we hypothesize that harmful and beneficial stimuli may be preferentially located at specific anatomical niches along the pathological environment triggering both beneficial and deleterious actions of these glial cells. According to this notion, there are no natural populations of detrimental microglia, but is the pathological environment that determines the final microglial phenotype.
Bilateral quadruple renal arteries
Authors: Miclaus Gratian D. , Matusz Petru 
Published: April 2012

AbstractVariation in the number of renal arteries (RAs) constitutes the most common and clinically important renal vascular variation. In this study, the authors describe a rare case of a 58‐year‐old male with eight RAs (bilateral quadruple) as revealed by routine multidetector computed tomography angiography. All the eight RAs originated from the abdominal aorta and penetrated the renal parenchyma at the level of renal sinus. The main RAs had the intraluminal diameter larger than the diameter of the additional renal arteries (AdRAs) at the origin. All the AdRAs had a greater length than the main RAs. These aspects are particularly important in planning microsurgical procedures. Clin. Anat. 25:973–976, 2012. © 2012 Wiley Periodicals, Inc.
Percutaneous coronary revascularization in coronary artery disease: Lessons from a single center experience
Authors: Aksoy Olcay , Tuzcu E. Murat , Ellis Stephen G. , Whitlow Patrick L. , Cam Akin , Batizy Lillian , Agarwal Shikhar , Franco Irving , Bajzer Christopher , Simpfendorfer Conrad , Raymond Russell , Nair Ravi , Cho Leslie , Shishehbor Mehdi H. , Lincoff A. Michael , Kapadia Samir R. 
Published: April 2012

AbstractObjectivesTo determine the role of percutaneous coronary intervention (PCI) and its impact on mortality in coronary artery disease (CAD).BackgroundIt's unclear whether PCI provides benefit in patients with CAD outside of acute settings. We sought to determine the role of PCI and its effect on mortality in patients with similar entry criteria to prior RCTs and compare outcomes with medical treatment.MethodsUsing institutional diagnostic catheterization database of consecutive patients undergoing coronary angiography from 1/2004 to 1/2010, we examined records for patients with a positive stress test and >70% coronary stenosis or symptoms of angina and >80% coronary stenosis. We excluded those with acute coronary syndromes, low ejection fraction (EF), history of CABG, and CABG following index catheterization. We stratified patients by treatment and performed unadjusted and propensity matched analyses. The outcome was all‐cause mortality obtained from the social security death index.ResultsWe identified 3,375 patients using study inclusion criteria. Mean age was 65 ± 11 years and 69% (n = 2,332) were men. Mean EF was 55% ± 8%. In the unadjusted cohort, 1,265 patients received medical management and 2,110 received PCI. The unadjusted analysis revealed significantly better survival in PCI patients (P < 0.0001) (HR: 0.51; 95% confidence interval (CI), 0.41–0.63). Propensity matching was performed for 1,580 patients and analysis showed better survival among patients receiving PCI (0 = 0.04) (HR: 0.74; 95% CI, 0.55–0.98). PCI continued to show better survival after excluding patients with malignancy (P = 0.03) and unstable angina (P = 0.007).ConclusionsThis single center registry analysis demonstrated better survival in stable CAD patients undergoing PCI compared to medical management alone. These data suggest there may be a benefit of PCI beyond symptom relief. Future randomized trials are needed to further understand the role of PCI in broader patient populations. © 2012 Wiley Periodicals, Inc.
A near‐infrared spectroscopy computational model for cerebral hemodynamics
Authors: Kannan R. , Przekwas A. 
Published: April 2012

SUMMARYNear infrared spectroscopy (NIRS) is a technique used to detect and measure changes in the concentrations of oxygenated hemoglobin, deoxygenated hemoglobin, and water in tissues based on the differential absorption, scattering, and refraction of the near infrared light. In this imaging technique, the optical properties of tissues are reconstructed from the measurements obtained from the sensors located on the boundary. A computational method for the rapid noninvasive detection ∕ quantification of cerebral hemorrhage is described using the above procedure. CFD Research Corporation's finite volume computational biology code was used to numerically mimic the NIRS procedure by (i) noninvasively ‘numerically penetrating’ the brain tissues and (ii) reconstructing the optical properties the presence of water, oxygenated, and deoxygenated blood. These numerical noninvasive measurements are then used to predict the extent and severity of the brain hemorrhage. The paper also discusses ideas to obtain the location and the severity of a localized injury. Two‐dimensional and three‐dimensional simulations are performed as a proof of concept for the numerical formulation being feasible for the above mentioned detection/quantification. The results demonstrate that this numerical NIRS formulation can be used as a noninvasive technique for both qualitative and quantitative evaluation of cerebral hemodynamics. Copyright © 2012 John Wiley & Sons, Ltd.