bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation of high‐impact polystyrene with processing and its recovery via the addition of styrene–butadiene rubber and styrene–ethylene–butylene–styrene block copolymer
Authors: Parres F. , Crespo J. E. 
Published: February 2011

AbstractThis work was divided into three parts. First, high‐impact polystyrene (HIPS) was submitted to a series of extrusion cycles with the objective of evaluating the consequent variations in its thermal and mechanical properties. The results showed slight variations in both the thermal and mechanical properties of HIPS. Second, degraded HIPS/styrene–ethylene–butylene–styrene (SEBS) blends and degraded HIPS/styrene–butadiene rubber (SBR) blends were prepared to evaluate the influence of the elastomeric concentration on the polymer's properties. The incorporation of SEBS or SBR allowed the recovery of the initial properties shown by virgin HIPS. Finally, blends of degraded HIPS with 2 wt % SEBS or SBR were extruded through four cycles. The mechanical properties remained constant with 2% SEBS added, whereas the mixtures of HIPS with 2% SBR showed an increase in the tensile strength as the number of extrusion cycles increased. The Vicat softening temperature decreased in both cases. The use of differential scanning calorimetry permitted the observation of differences in the crosslinking reactions of different samples as a function of the number of extrusion cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Controllable properties and microstructure of hydrogels based on crosslinked poly(ethylene glycol) diacrylates with different molecular weights
Authors: Zhang Hongbin , Wang Lei , Song Li , Niu Guoguang , Cao Hui , Wang Guojie , Yang Huai , Zhu Siquan 
Published: February 2011

AbstractThis work describes a comprehensive study of hydrogels based on polyethylene glycol diacrylates (PEGDAs) with the molecular weight (MW) range of 400–2000. The blends of low‐ and high‐molecular weight PEGDA macromers with different ratios were photopolymerized under visible light irradiation, using a blue light sensitive photoinitiator Irgacure819, at the total polymer concentration of 60 wt %. Swelling ratios, wetting property, elastic moduli, transparency, and the microstructure of the resulting hydrogels were investigated. Among them, equilibrium water contents, hydrophilicity, and mesh size of the hydrogels increased while the elastic moduli decreased when increased the PEGDA MW or the content of higher MW PEGDA in the blends. Most of the hydrogels possessed excellent transparency in visible region. The viability of L929 cells on the surface of hydrogel was also estimated. All the selected hydrogels exhibited a relatively high proliferation rate, which demonstrated this hydrogel system with photoinitiator Irgacure819 had good biocompatibility. These results show the properties of PEGDA hydrogel could be easily adjusted by varying PEGDA MW or the ratios of low‐ and high‐MW macromers in the composites. It could be helpful for the design of proper PEGDA hydrogels in the applications as tissue engineering or drug delivery system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
An efficient method for nitration of aromatic compounds over solid acid and polymer‐supported sodium nitrite
Authors: Karimi Zarchi Mohammad Ali , Rahmani Fahimeh 
Published: February 2011

AbstractA variety of aromatic compounds are nitrated under heterogeneous conditions using a polymer‐supported hydrochloric acid, [P4‐(VP)]HCl, with a polymer‐supported sodium nitrite, [P4‐VP]NO2, or sodium nitrite in ethanol at room temperature with high yields. This methodology is useful for nitration of activated aromatic compounds. In this procedure, the work‐up is very easy, and the spent polymeric reagent can be regenerated and reused. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Role of interface on dynamic modulus of high‐performance poly(etheretherketone)/ceramic composites
Authors: Goyal R. K. , Tiwari A. N. , Negi Y. S. 
Published: February 2011

AbstractHigh‐performance printed circuit board or electronic packaging substrate with low warping particularly at high frequency is the key demand of manufacturers. In the present work, poly(etheretherketone) (PEEK) matrix composites reinforced with untreated micron size aluminum nitride (AlN) and alumina (Al2O3) particles have been studied for dynamic modulus in the temperature range varying from 30 to 250°C. At 48 vol % particles, the room temperature modulus of the PEEK/AlN composites increased by approximately fivefold (∼ 23 GPa), whereas it increased by twofold for PEEK/Al2O3composite. The reinforcing efficiency is more pronounced at higher temperatures. The significant improvement in modulus was attributed to the better adhesion between the matrix and the AlN particles. Scanning electron microscope (SEM) and Kubat parameter showed that the poor adhesion between the matrix and the Al2O3particles resulted in comparatively smaller increase in modulus of PEEK/Al2O3, despite higher intrinsic modulus of Al2O3than that of AlN. SEM showed almost uniform distribution of particles in the matrix. The experimental data were correlated with several theoretical models. The Halpin–Tsai model with ξ (xi) is equal to four correlates well up to 48 vol % AlN composites while ξ is equal to two correlates only up to 18 vol % Al2O3composites. Guth–Smallwood model also correlates well up to 28 vol % AlN and 18 vol % Al2O3‐filled composites. Thereafter, data deviated from it due to the particles tendency to aggregate formation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of chitin‐polyaniline nanocomposite by electron beam irradiation
Authors: Ramaprasad A. T. , Rao Vijayalakshmi , Sanjeev Ganesh 
Published: February 2011

AbstractIn this article, we report a novel method to synthesize polyaniline (PANI) nanocomposite. Chitin and PANI are dissolved in a common solvent, N,N‐dimethyl acetamide, with 5% LiCl, and the solution is irradiated with 8 MeV electron beam for different doses, nanoparticles of PANI in chitin is obtained. The characterization of the composite was done by UV–vis absorption spectrum, FTIR, thermogravimetric analysis (TGA), X‐ray diffraction, scanning electron microscopic (SEM), and DC conductivity studies. UV–vis studies show conversion of emeraldine base form to leucoemaraldine base. FTIR studies show interaction between chitin and PANI. SEM analysis of irradiated composite shows formation of PANI particulates. Average particle size varies from ≈40 to ≈1000 nm. DC conductivity of blend improves on irradiation. One‐dimensional variable range hopping conduction mechanism is dominating in the irradiated blend. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Performance and biodegradability of a maleated polyester bioplastic/recycled sugarcane bagasse system
Authors: Wu Chin‐San 
Published: February 2011

AbstractThe biodegradability, morphology, and mechanical properties of composite materials made of poly(butylene succinate adipate) (PBSA) and sugarcane bagasse (SCB) were evaluated. Composites containing maleic anhydride (MA)‐grafted PBSA (PBSA‐g‐MA/SCB) exhibited noticeably superior mechanical properties because of greater compatibility between the two components. The dispersion of SCB in the PBSA‐g‐MA matrix was highly homogeneous as a result of ester formation between the carboxyl groups of PBSA‐g‐MA and hydroxyl groups in SCB and the consequent creation of branched and crosslinked macromolecules. Each composite was subjected to biodegradation tests in a Rhizopus oryzae compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the PBSA and the PBSA‐g‐MA/SCB composite films were eventually completely degraded. The PBSA‐g‐MA/SCB films were more biodegradable than those made of PBSA and exhibited a higher intrinsic viscosity, implying a strong connection between these characteristics and biodegradability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Geophysical prospection of a bronze foundry on the southern slope of the acropolis at athens, Greece
Authors: Leopold Matthias , Gannaway Evey , Völkel Jörg , Haas Florian , Becht Michael , Heckmann Tobias , Westphal Markus , Zimmer Gerhard 
Published: February 2011

AbstractThe sanctuary of the Acropolis of Athens in Greece provided one of the first monumental bronze statues some 2500 years ago, which was dedicated to the goddess Athena. During recent decades, important understanding of the statue's manufacturing processes has been achieved by archaeological studies, and the former production site has been identified on the southern slope of the Acropolis. Two major bronze production pits have been detected and one was excavated in 2001 and 2006 and was found in an unexpected location. Therefore, in 2010 a geophysical survey of the whole production site was carried out for the first time in order to either reveal or to exclude any further sites of the bronze foundry complex. A combination of different geophysical methods was applied to survey the subsurface; magnetometry (MAG), two‐ and three‐dimensional electrical resistivity tomography (ERT), as well as two‐ and three‐dimensional ground‐penetrating radar (GPR). Two major anomalies have been identified in the processed data, which provide evidence for additional production sites. One was a known site identified in a test trench in 2001, and our survey has outlined the extent of the former pit. The other anomaly, which was detected by ERT and GPR, was 8–10 m in length and 2–3 m in width and is oval‐shaped and about 2.5 m deep. Steep vertical walls, together with two narrow points at the ends of the pit, which could reflect former entrances, were identified. Virtual ERT and GPR models generated from cross‐sections of a ground‐based LiDAR scan of the 2001 and 2006 excavated pit helped to interpret and understand the geophysical data of anomaly 2. This anomaly was finally interpreted as a newly detected production pit of the bronze foundry complex, and based on these findings new excavations are planned. Copyright © 2011 John Wiley & Sons, Ltd.
The scholarly impact of TRECVid (2003–2009)
Authors: Thornley Clare V. , Johnson Andrea C. , Smeaton Alan F. , Lee Hyowon 
Published: February 2011

AbstractThis paper reports on an investigation into the scholarly impact of the TRECVid (Text Retrieval and Evaluation Conference, Video Retrieval Evaluation) benchmarking conferences between 2003 and 2009. The contribution of TRECVid to research in video retrieval is assessed by analyzing publication content to show the development of techniques and approaches over time and by analyzing publication impact through publication numbers and citation analysis. Popular conference and journal venues for TRECVid publications are identified in terms of number of citations received. For a selection of participants at different career stages, the relative importance of TRECVid publications in terms of citations vis à vis their other publications is investigated. TRECVid, as an evaluation conference, provides data on which research teams ‘scored’ highly against the evaluation criteria and the relationship between ‘top scoring’ teams at TRECVid and the ‘top scoring’ papers in terms of citations is analyzed. A strong relationship was found between ‘success’ at TRECVid and ‘success’ at citations both for high scoring and low scoring teams. The implications of the study in terms of the value of TRECVid as a research activity, and the value of bibliometric analysis as a research evaluation tool, are discussed.
Counting first, last, or all authors in citation analysis: A comprehensive comparison in the highly collaborative stem cell research field
Authors: Zhao Dangzhi , Strotmann Andreas 
Published: February 2011

AbstractHow can citation analysis take into account the highly collaborative nature and unique research and publication culture of biomedical research fields? This study explores this question by introducing last‐author citation counting and comparing it with traditional first‐author counting and theoretically optimal all‐author counting in the stem cell research field for the years 2004–2009. For citation ranking, last‐author counting, which is directly supported by Scopus but not by ISI databases, appears to approximate all‐author counting quite well in a field where heads of research labs are traditionally listed as last authors; however, first author counting does not. For field mapping, we find that author co‐citation analyses based on different counting methods all produce similar overall intellectual structures of a research field, but detailed structures and minor specialties revealed differ to various degrees and thus require great caution to interpret. This is true especially when authors are selected into the analysis based on citedness, because author selection is found to have a greater effect on mapping results than does choice of co‐citation counting method. Findings are based on a comprehensive, high‐quality dataset extracted in several steps from PubMed and Scopus and subjected to automatic reference and author name disambiguation.
Enhanced absorption of millimeter wave energy in murine subcutaneous blood vessels
Authors: Alekseev Stanislav I. , Ziskin Marvin C. 
Published: February 2011

AbstractThe aim of the present study was to determine millimeter wave (MMW) absorption by blood vessels traversing the subcutaneous fat layer of murine skin. Most calculations were performed using the finite‐difference time‐domain (FDTD) technique. We used two types of models: (1) a rectangular block of multilayer tissue with blood vessels traversing the fat layer and (2) cylindrical models with circular and elliptical cross‐sections simulating the real geometry of murine limbs. We found that the specific absorption rate (SAR) in blood vessels normally traversing the fat layer achieved its maximal value at the parallel orientation of the E‐field to the vessel axis. At 42 GHz exposure, the maximal SAR in small blood vessels could be more than 30 times greater than that in the skin. The SAR increased with decreasing the blood vessel diameter and increasing the fat thickness. The SAR decreased with increasing the exposure frequency. When the cylindrical or elliptical models of murine limbs were exposed to plane MMW, the greatest absorption of MMW energy occurred in blood vessels located on the lateral areas of the limb model. At these areas the maximal SAR values were comparable with or were greater than the maximal SAR on the front surface of the skin. Enhanced absorption of MMW energy by blood vessels traversing the fat layer may play a primary role in initiating MMW effects on blood cells and vasodilatation of cutaneous blood vessels. Bioelectromagnetics 32:423–433, 2011. © 2011 Wiley‐Liss, Inc.
Insulin increases macrophage triglyceride accumulation under diabetic conditions through the down regulation of hormone sensitive lipase and adipose triglyceride lipase
Authors: Meilin Edna , Aviram Michael , Hayek Tony 
Published: February 2011

AbstractDiabetes mellitus (DM) is a major risk factor for the development of atherosclerosis, and high‐serum levels of insulin are strongly associated with type 2 DM. Atherosclerosis is characterized by lipid‐laden macrophage foam cell formations, which contain substantial amount of cholesterol and triglycerides (TG). This study analyzed for the first time, the effects of insulin on TG metabolism in macrophages under normal and diabetic conditions. Mouse peritoneal macrophages from C57BL6 mice were cultured under normal (5 mM) or high (diabetic condition, 25 mM) glucose concentration, with or without insulin, followed by the assessment of TGs metabolism in these cells. Under diabetic condition, insulin increased TG accumulation in macrophages by 100%, decreased cellular TG degradation by 21%, and increased C‐reactive protein levels in macrophages by 83%. Insulin decreased hormone‐sensitive lipase mRNA and protein expression by 28 and 60%, respectively, and adipose TG lipase (ATGL) protein expression by 36%, with no significant reduction in ATGL mRNA levels. The inhibition of insulin‐mediated phosphorylation, and the addition of cyclic adenosine 3′5′‐monoposphate, abolished the insulin‐mediated inhibition of TGs degradation in cells. Insulin increases macrophage TGs accumulation only under diabetic conditions, suggesting that impaired glycemic control in diabetic patients treated with insulin may contribute to foam cell formations and enhanced inflammation in macrophages.
Different Active‐Site Loop Orientation in Serine Hydrolases versus Acyltransferases
Authors: Jiang Yun , Morley Krista L. , Schrag Joseph D. , Kazlauskas Romas J. 
Published: February 2011

AbstractAcyl transfer is a key reaction in biosynthesis, including synthesis of antibiotics and polyesters. Although researchers have long recognized the similar protein fold and catalytic machinery in acyltransferases and hydrolases, the molecular basis for the different reactivity has been a long‐standing mystery. By comparison of X‐ray structures, we identified a different oxyanion‐loop orientation in the active site. In esterases/lipases a carbonyl oxygen points toward the active site, whereas in acyltransferases a NH of the main‐chain amide points toward the active site. Amino acid sequence comparisons alone cannot identify such a difference in the main‐chain orientation. To identify how this difference might change the reaction mechanism, we solved the X‐ray crystal structure of Pseudomonas fluorescens esterase containing a sulfonate transition‐state analogue bound to the active‐site serine. This structure mimics the transition state for the attack of water on the acyl–enzyme and shows a bridging water molecule between the carbonyl oxygen mentioned above and the sulfonyl oxygen that mimics the attacking water. A possible mechanistic role for this bridging water molecule is to position and activate the attacking water molecule in hydrolases, but to deactivate the attacking water molecule in acyl transferases.
Repeated successful balloon valvuloplasty of a bioprosthetic aortic valve in a nonagenerian
Authors: Dejam Andre , Hokinson Michelle , Laham Roger 
Published: February 2011

AbstractCalcific aortic stenosis remains a major cause of mortality and morbidity in the aging population. Surgical replacement remains the treatment of choice for this disease. Balloon aortic valvuloplasty was introduced as a palliative procedure for these patients, but was tempered by a high rate of recurrence, which has limited its usefulness. However, the introduction of smaller‐profile balloons, rapid pacing, and closure devices have brought it back as an alternative treatment strategy in selected patients who are at too high risk for surgery with repeat valvuloplasty as needed for recurrences. We report a case of prosthetic aortic valve stenosis treated with valvuloplasty with intracardiac and fluoroscopic guidance with recurrence treated with repeat valvuloplasty with promising intermediate‐term outcome and describe the growing valve in valve procedures. © 2011 Wiley‐Liss, Inc.
Myocardial infarction in a youngster Due to giant coronary aneurysm
Authors: Dhakam Sajid , Rahman Nasir 
Published: February 2011

AbstractA 22‐year old male presented with acute inferior wall myocardial infarction. Coronary angiogram revealed normal left coronary arteries and a giant coronary aneurysm in Right coronary artery (RCA). Primary angioplasty of RCA was performed. Large thrombus burden was retrieved with aspiration device and coronary flow restored. However, despite best efforts some thrombus remained and decision to stent was deferred to a later date. Dimensions of aneurysm on quantitative coronary angiogram were 15 mm in width and 46 mm in length. Two weeks later coronary angiogram revealed normal flow in RCA without any angiographically visible thrombus. PCI was performed with two 3.0 × 28 mm Covered stents, Graft Master (JoStent) deployed across the aneurysm, overlapping each other. This completely sealed the aneurysm and intravascular ultrasound confirmed no leakage through the covered stents. Patient remains asymptomatic 2 months post procedure on triple antiplatelet therapy. © 2011 Wiley‐Liss, Inc.
Interstitial pore‐water temperature dynamics across a pool‐riffle‐pool sequence
Authors: Krause Stefan , Hannah David M. , Blume Theresa 
Published: February 2011

AbstractHyporheic habitat conditions are controlled strongly by spatial and temporal dynamics of physicochemical processes at the aquifer–river interface. In particular, heat transport between groundwater and surface water has a great impact on streambed habitats. This study uses high resolution observations of vertical hydraulic gradients (VHGs) and interstitial pore‐water temperatures to investigate space‐time patterns of groundwater–surface water (GW–SW) exchange fluxes and streambed thermal conditions of a pool‐riffle‐pool sequence of a UK lowland river. The results indicate that, although groundwater is dominantly upwelling in the research area, exchange flow patterns are strongly influenced by the streambed geomorphology. Advective heat flux caused by groundwater upwelling is shown to have a moderating impact on interstitial temperature patterns and partly compensates the impact of conduction of diurnal surface water temperature fluctuations into the streambed. Consequently, diurnal temperature oscillations, which are clearly pronounced in the top 10 cm of the streambed (up to 2 °C) are reduced by > 90% at depths below 20 cm. This study provides evidence that even in groundwater upwelling conditions, the spatially variable impact of heat conduction from the streambed surface may cause a spatially heterogeneous interstitial habitat structure with thermal conditions differing significantly in a vertical (3 °C temperature gradient at a length scale of 0·4 m) as well as longitudinal (0·75 °C at 16 m) domain. These results not only enhance the understanding of thermal patterns in lowland rivers but also have implications for interstitial habitat ecohydrology, community structures and stability. Copyright © 2011 John Wiley & Sons, Ltd.
Hydrological storage and transmission characteristics of an alpine talus
Authors: Muir Danika L. , Hayashi Masaki , McClymont Alastair F. 
Published: February 2011

AbstractAlpine watersheds are the source region of some of the largest rivers in North America and elsewhere. Understanding of hydrological processes in alpine watersheds is important for understanding the response of river basins to meteorological forcing. Talus units in alpine watersheds have been suggested in the literature as potential reservoirs of groundwater, but relatively little is known about hydrological processes in talus. To develop conceptual understanding of alpine talus and determine its storage capacity and hydraulic properties, we investigated a talus unit in the Lake O'Hara watershed in the Canadian Rockies using ground‐penetrating radar, electrical resistivity tomography, measurements of talus discharge, tracer tests, and isotopic hydrograph separation. The study talus, consisting mainly of quartzite and carbonate rock fragments, had very high hydraulic conductivity (0·01–0·03 m s−1) and fast hydrograph recession (exponential decay coefficient of 1 d−1), suggesting that its storage capacity is limited to a time scale of less than a week. Groundwater flow through the talus occurs in a relatively thin (0·01–0·1 m) saturated zone at the base of the talus, which appears to have discrete flow paths rather than a single continuous sheet. A late‐lying snowpack, located at the top of the talus and cliff ledges above, sustains baseflow discharging from the talus, which provides moisture to alpine meadows downstream. Although this study indicates limited storage capacity of talus, further research is required to examine the storage and transmission characteristics of talus consisting of different types of geological materials or formed in different environments. Copyright © 2011 John Wiley & Sons, Ltd.