bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coaxial electrospinning of P(LLA‐CL)/heparin biodegradable polymer nanofibers: potential vascular graft for substitution of femoral artery
Authors: Zhai Wei , Qiu Li‐jun , Mo Xiu‐mei , Wang Sheng , Xu Yun‐fei , Peng Bo , Liu Min , Huang Jun‐hua , Wang Guang‐chun , Zheng Jun‐hua 
Published: June 2013

AbstractElectrospinning is one of the most simple and effective methods to prepare polymer fibers with the diameters ranging from nanometer to several micrometers. Poly(L‐lactide)‐co‐poly (ɛ‐caprolactone) (P(LLA‐CL)) fibers and P(LLA‐CL)/heparin coaxial composite fibers herein were successfully prepared by single electrospinning and coaxial electrospinning, respectively. The prepared endothelialized P(LLA‐CL) and P(LLA‐CL)/heparin vascular grafts were used in the Beagle dogs experiment to evaluate the feasibility of thus made different scaffolds for substitution of dog femoral artery in early period, medium term, and long term, meanwhile the pure P(LLA‐CL) vascular graft was used as the control group during all the experiments. The animal model was established by using the graft materials to anastomose both femoral arteries of dogs. The vascular grafts patency rates (i.e., the unobstructed capacity of blood vessel) were detected by color Doppler flow imaging technology and digital subtraction angiography. To observe the histological morphology at different periods, the vascular grafts were removed after 7, 14, and 30 days, and the corresponding histological changes were evaluated by hematoxylin and eosin staining. The experimental results show that in the early period, the patency rates of pure P(LLA‐CL) graft, endothelial P(LLA‐CL) graft, and P(LLA‐CL)/heparin graft were 75%, 75%, and 100%, respectively; in the medium term, the patency rates of pure P(LLA‐CL) graft and endothelial P(LLA‐CL) graft were 25%, whereas that of P(LLA‐CL)/heparin graft was 50%; the patency rates of pure P(LLA‐CL) graft and endothelial P(LLA‐CL) graft were down to 0%, whereas the patency rate of P(LLA‐CL)/heparin graft was 25% in the long term. This preliminary study has demonstrated that P(LLA‐CL)/heparin coaxial composite fiber maybe a reliable artificial graft for the replacement of femoral artery. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 471–478, 2019.
Quantitation of cholesterol and phospholipid sorption on silicone hydrogel contact lenses
Authors: Pitt William G. , Perez Krystian X. , Tam Ngai Keung , Handly Erika , Chinn Joseph A. , Liu Xiaojun Michael , Maziarz Edmond Peter 
Published: June 2013

AbstractThe introduction of silicone hydrogel (SiHy) contact lenses to the consumer marketplace necessitates study of the susceptibility of these lenses to spontaneous deposition by hydrophobic lipid components of ocular tears. The use of radioisotopes to measure lipid sorption on SiHy contact lenses gives precise and accurate results but requires institutional infrastructure and compels efficient lipid removal from the lens. This study compares three methods of quantitating phospholipid and cholesterol sorption on SiHy lenses using radiolabeled cholesterol and phosphatidylcholine that were sorbed on lenses from an artificial tear fluid. A triple extraction technique using n‐propanol gives the most reliable results. Comparison of sorption on SiHy lenses shows that balafilcon A and senofilcon A lenses sorb similar amounts, while lotrafilcon B lenses sorb comparatively less. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1516–1523, 2013.
Quantitative characterization of porous commercial and experimental bone graft substitutes with microcomputed tomography
Authors: Ylä‐Soininmäki Anne , Moritz Niko , Turco Gianluca , Paoletti Sergio , Aro Hannu T. 
Published: June 2013

AbstractA large number of resorbable bone graft substitutes are being marketed as porous, but the total porosity being referred does not take into account many of the biologically important physical aspects of porosity. Therefore, to allow the direct comparison of different commercial products, there is a need to adopt guidelines for a standardized characterization. The aim of the study was to assess a microcomputed tomography‐based method for the characterization of porous biomaterials to allow head‐to‐head comparison of these materials. The study included two commercial biomaterials (Actifuse® and ChronOs®) and three experimental biomaterials (sintered bioactive glass microspheres, porous alginate (Alg), and porous Alg/hydroxyapatite composite). In addition to porosity and pore size distributions, the interconnectivity of the pores was assessed by an iterative blocking of interconnections. The biomaterials were characterized in their original morphologies (granules or cones). Differences between the materials were demonstrated. Actifuse® had the broadest distributions of pores and interconnections. ChronOs® had a substantial fraction of closed pores (10%). Other materials had closed porosity below 1%. Due to the thinner walls of the lattice, the Alg‐based materials had high total porosity (>80%). Discrepancies were found between the porosity values reported by the manufacturers and the values obtained in this study. The proposed method is plausible for the systematic characterization of porous biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1538–1548, 2013.
Effectiveness of novel xylanases belonging to different GH families on lignin and hexenuronic acids removal from specialty sisal fibres
Authors: Valenzuela Susana Valeria , Valls Cristina , Roncero M. Blanca , Vidal Teresa , Diaz Pilar , Pastor F.I. Javier 
Published: June 2013

AbstractBACKGROUNDThe effectiveness of xylanases on lignin removal from pulps differs widely depending on the enzyme family, the type of pulp and the bleaching sequence among other factors. Xylanases can also reduce the presence of undesirable hexenuronic acids in the papermaking fibers. The performance of non‐commercial xylanases belonging to families GH10, GH30, GH30‐CBM35 and GH11, and of the multicomponent xylanase from Paenibacillus barcinonensis for lignin and hexenuronic acids removal from sisal (Agave sisalana) has been evaluated.RESULTSSisal pulps were bleached by an XP sequence, where X denotes the enzyme treatment and P a hydrogen peroxide extraction stage. Kappa number, brightness, viscosity and hexenuronic acid content of samples were determined. Sugars released from sisal pulps, other non‐wood fibres and also eucalyptus fibres, by the treatment with xylanases were also analysed. The best results were obtained with the GH10 xylanase and with crude supernatants of P. barcinonensis, which produced a lignin removal of 23% and a reduction of 25% in the hexenuronic acid content of sisal pulps without a significant loss of viscosity.CONCLUSIONThe release of sugars in the effluents from the X stage applied to sisal correlated with the effectiveness of the xylanases tested. The xylan content of wood and non‐wood fibres, the type of xylan and its accessibility also had an influence on the xylanase activity on pulps. © 2013 Society of Chemical Industry
Mixed matrix membranes for process intensification in electrodialysis of amino acids
Authors: Kattan Readi O. M. , Rolevink E. , Nijmeijer K. 
Published: June 2013

AbstractBACKGROUNDAmino acids are valuable intermediates in the biobased economy for the production of chemicals. Electro‐membrane processes combined with enzymatic modification have been investigated as an alternative technology for the fractionation of a mixture of amino acids with almost identical charge behavior. Up to now, the modification and subsequent separation were performed in two separate reactors. An interesting approach is the integration of both unit operations into one single device using mixed matrix membranes (MMMs) as platform for enzymatic conversion.RESULTSMMMs containing the enzyme glutamic acid decarboxylase (GAD, EC 4.1.1.15) Relizyme EP403/S as carrier were prepared showing satisfactory mechanical stability and enzymatic activity for L‐glutamic acid conversion into γ‐aminobutyric acid (GABA). ED with integrated MMM for simultaneous enzymatic decarboxylation of L‐glutamic acid to GABA (33% conversion) and further separation of L‐aspartic acid and unconverted L‐glutamic acid from GABA was successful leading to current efficiency of 40% and low energy consumption of 3 kWh kg‐1.CONCLUSIONSTogether with the high mechanical stability obtained for the MMMs, this opens the route towards process intensification, combining enzymatic conversion and separation with electrodialysis in one integrated process for the successful isolation of amino acids for biorefinery applications. © 2013 Society of Chemical Industry
Photoreduction of nitrogen trifluoride with controlled release of radicals
Authors: Liu Xingang , Zhang Jiahui , Zhang Renxi , Hou Huiqi , Chen Shanping , Zhang Yi 
Published: June 2013

AbstractBACKGROUNDWith the rapid growth of the semiconductor and thin film transistor liquid crystal display manufacturing industries, large quantities of the potent greenhouse gas nitrogen trifluoride (NF3) is in demand. But perfluorocarbons are very stable compounds because of their molecular structures. Therefore, in the atmosphere, NF3 is difficult to oxidize by O3, NO, NO2, and OH radicals, except by excited oxygen atoms O(1D) that can react with it to form NF2 or other products. In this study the possible degradation process of NF3 in the ‘controlled release of radicals’ reactor is discussed.RESULTSUnder the conditions of 5 mmHg partial pressure of NF3 and 600 mmHg total pressure with buffer gas of argon, NF3 was photodegraded in an in situ reactor with a ‘controlled release of radicals’ system. The results indicated that reductive double bonds and allyl radicals, slowly released from polyisoprene irradiated by a UV lamp emitting 185 and 253.7 nm of light, could contribute to the NF3 degradation in the CRR system. The NF3 degradation efficiency, significantly affected by O2 and almost independent of N2, reached 96% with a kinetic rate constant k ≈ 1.77 × 10−4 s−1 after 300 min of ultraviolet irradiation.CONCLUSIONAccording to the experimental results, a potential way of continuous photoreduction of NF3 was found, since excited double bonds and allyl radicals are consequently released by irradiating the surface of the polymer matrix. The considerable degradation reaction constant of NF3 and no fluoride byproducts in gas make it possible for industry application. © 2013 Society of Chemical Industry
Optical studies of rocket exhaust trails and artificial noctilucent clouds produced by Soyuz rocket launches
Authors: Dalin P. , Perminov V. , Pertsev N. , Dubietis A. , Zadorozhny A. , Smirnov A. , Mezentsev A. , Frandsen S. , Grønne J. , Hansen O. , Andersen H. , McEachran I. , McEwan T. , Rowlands J. , Meyerdierks H. , Zalcik M. , Connors M. , Schofield I. , Veselovsky I. 
Published: June 2013

AbstractDetailed tracing of an exhaust plume from a rocket's initial trajectory is a scientifically and diagnostically useful technique. It can provide detailed information on the atmosphere's mean winds, wind shears, turbulent regime, and physical state over a wide altitude range from 50 to 200 km. We analyze Soyuz rocket exhaust plumes from Plesetsk on 21 May 2009 and 27 June 2011, which uncovered significantly different atmospheric states and underlying dynamics. The first case showed highly dynamical conditions in the mesosphere, characterized by vortex structures, wind shears, and small‐scale turbulent eddies. The estimated turbulent energy dissipation rates ranged 330–460 mW kg−1. A characteristic balloon‐shaped trail was observed at altitudes between 105 and 160 km, having rapid expansion rates of 500–800 m s−1 over the time period of 2 min which can be explained by complex gas dynamic processes in the rocket wake involving the collision of shock waves. In the second case, we show evidence that the rocket exhaust trail persisted without any changes during its motion from Plesetsk via Denmark to the UK for 9 h, indicating extremely stable atmospheric conditions. This case introduces a new state of the summer mesosphere—remarkably quiet conditions, probably never observed before. The rocket plumes studied, related to the initial rocket trajectory, are essentially twilight phenomena as seen from the ground using wideband spectrum cameras, that is, the Sun should be below the horizon by 6°. For the first time, we analyze the dynamics of rocket exhaust products at the initial trajectory in the mesosphere and lower thermosphere using detailed photographic imaging taken from the ground.
Concurrent variation between the East Asian subtropical jet and polar front jet during persistent snowstorm period in 2008 winter over southern China
Authors: Liao Zhijie , Zhang Yaocun 
Published: June 2013

AbstractThe concurrent variation features between the East Asian subtropical jet and polar front jet were investigated during persistent snowstorm period in 2007/2008 winter over southern China. The East Asian subtropical jet was divided into two parts: (1) the plateau jet, located along the southern side of the Tibetan Plateau, and (2) the ocean jet, situated at the southeastern Japan Island. The concurrent intensity variation among the polar front jet, plateau jet, and ocean jet and the associated atmospheric anomalous signals were examined. A possible mechanism for concurrent variation among the three jets was also investigated from a perspective of synoptic‐scale transient eddy activities (STEA). The enhanced plateau jet was simultaneously correlated with the weakened polar front jet, while the variation of the ocean jet lagged the variation of the plateau jet (polar front jet) about 5 days. The concurrent variation between the plateau jet and the polar front jet acted as an important bridge that linked the snowstorm to the atmospheric anomalous signals associated with the cold and warm air activities. Due to the opposite trends of STEA variation over the southern and northern sides of the Tibetan Plateau, the plateau jet and the polar front jet exhibited a significant concurrent variation feature. The STEA anomalies over the plateau jet and polar front jet regions propagated downstream to the East Asian coast as a wave train along the southern and northern sides of the Tibetan Plateau, respectively, resulting in a 5 day lag variation relationship between the ocean jet and the plateau jet (polar front jet).
Regional dynamics of forest canopy change and underlying causal processes in the contiguous U.S.
Authors: Schleeweis Karen , Goward Samuel N. , Huang Chengquan , Masek Jeffrey G. , Moisen Gretchen , Kennedy Robert E. , Thomas Nancy E. 
Published: June 2013

AbstractThe history of forest change processes is written into forest age and distribution and affects earth systems at many scales. No one data set has been able to capture the full forest disturbance and land use record through time, so in this study, we combined multiple lines of evidence to examine trends, for six US regions, in forest area affected by harvest, fire, wind, insects, and forest conversion to urban/surburban use. We built an integrated geodatabase for the contiguous U.S. (CONUS) with data spanning the nation and decades, from remote sensing observations of forest canopy dynamics, geospatial data sets on disturbance and conversion, and statistical inventories, to evaluate relationships between canopy change observations and casual processes at multiple scales. Results show the variability of major change processes through regions across decades. Harvest affected more forest area than any other major change processes in the North East, North Central, Southeast, and South central regions. In the Pacific Coast and Intermountain West, more forest area was affected by harvest than forest fires. Canopy change rates at regional scales confounded the trends of individual forest change processes, showing the importance of landscape scale data. Local spikes in observed canopy change rates were attributed to wind and fire events, as well as volatile harvest regimes. This study improves the geographic model of forest change processes by updating regional trends for major disturbance and conversion processes and combining data on the dynamics of fire, wind, insects, harvest, and conversion into one integrated geodatabase for the CONUS.
On Switching to H‐Free Graphs
Authors: Jelínková Eva , Kratochvíl Jan 
Published: June 2013

AbstractIn this article, we study the problem of deciding if, for a fixed graph H, a given graph is switching equivalent to an H‐free graph. Polynomial‐time algorithms are known for H having at most three vertices or isomorphic to P4. We show that for H isomorphic to a claw, the problem is polynomial, too. On the other hand, we give infinitely many graphs H such that the problem is NP‐complete, thus solving an open problem [Kratochvíl, Nešetřil and Zýka, Ann Discrete Math 51 (1992)]. Further, we give a characterization of graphs switching equivalent to a K1, 2‐free graph by ten forbidden‐induced subgraphs, each having five vertices. We also give the forbidden‐induced subgraphs for graphs switching equivalent to a forest of bounded vertex degrees.
Simultaneous measurement of tissue oxygen level‐dependent (TOLD) and blood oxygenation level‐dependent (BOLD) effects in abdominal tissue oxygenation level studies
Authors: Ding Yao , Mason Ralph P. , McColl Roderick W. , Yuan Qing , Hallac Rami R. , Sims Robert D. , Weatherall Paul T. 
Published: June 2013

PurposeTo assess oxygenation in abdominal organs with magnetic resonance imaging (MRI), a novel approach is presented to simultaneously measure both T1‐ and ‐maps serially during a single dynamic MRI scan in response to an oxygen challenge.Materials and MethodsThe proposed acquisition scheme consists of a multishot multiecho gradient echo planar imaging sequence (ms‐GEPI) interleaved with a multishot inversion recovery echo planar imaging (ms‐IR‐EPI) sequence. Respiratory motion compensation was accomplished with standard belt triggering and by acquiring all image data at the same phase of expiration. This respiratory‐triggered, free‐breathing, interleaved tissue oxygenation level‐dependent (TOLD) and blood oxygenation level‐dependent (BOLD) acquisition technique was validated on phantoms and seven healthy volunteers in response to an oxygen challenge.ResultsMeasurements of relaxation times both in vitro and in vivo were in good agreement with those obtained using conventional pulse sequences and reported in the literature. The interleaved sequence was able to measure oxygen‐induced relaxation time changes in human abdominal organs.ConclusionThe free‐breathing respiratory‐triggered interleaved T1 and sequence successfully provided relaxation time maps of abdominal organs in a dynamic scan without the need for image registration. The simultaneous monitoring of tissue and blood oxygenation improves time efficiency and should enhance studies comparing dynamic T1 and data within the abdomen. J. Magn. Reson. Imaging 2013;38:1230–1236. © 2013 Wiley Periodicals, Inc.
A retrospective comparison of smart prep and test bolus multi‐detector CT pulmonary angiography protocols
Authors: Suckling Tara , Smith Tony , Reed Warren 
Published: June 2013

AbstractIntroductionOptimal arterial opacification is crucial in imaging the pulmonary arteries using computed tomography (CT). This poses the challenge of precisely timing data acquisition to coincide with the transit of the contrast bolus through the pulmonary vasculature. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk.MethodsA total of 160 CTPA examinations (80 using each protocol) performed between January 2010 and February 2011 were assessed retrospectively. CT attenuation coefficients were measured in Hounsfield Units (HU) using regions of interest at the level of the pulmonary trunk. The average pixel value, standard deviation (SD), maximum, and minimum were recorded. For each of these variables a mean value was then calculated and compared for these two CTPA protocols.ResultsMinimum opacification of 200 HU was achieved in 98% of the TBP sample but only 90% of the SPP sample. The average CT attenuation over the pulmonary trunk for the SPP was 329 (SD = ±21) HU, whereas for the TBP it was 396 (SD = ±22) HU (P = 0.0017). The TBP also recorded higher maximum (P = 0.0024) and minimum (P = 0.0039) levels of opacification.ConclusionThis study has found that a TBP resulted in significantly better opacification of the pulmonary trunk than the SPP.
Comparison of leafy kale populations from Italy, Portugal, and Turkey for their bioactive compound content: phenolics, glucosinolates, carotenoids, and chlorophylls
Authors: Ferioli Federico , Giambanelli Elisa , D'Antuono L Filippo , Costa Helena S , Albuquerque Tânia G , Silva Ana S , Hayran Osman , Koçaoglu Bike 
Published: June 2013

AbstractBACKGROUNDKales are primitive leafy Brassica oleracea L. forms, widespread in local farming systems of several European countries and employed in the preparation of traditional recipes. Kales are also potential sources of healthy bioactive phytochemical components. The present study compared the bioactive compound content of kale populations from Italy, Portugal, and Turkey, either from local sources or grown in an experimental field.RESULTSTotal phenolics, glucosinolates (GLS), carotenoids, and chlorophylls were in the ranges 8310–38 110, 755–8580, 135–2354, and 1740–16 924 mg kg−1 dry matter, respectively. On average, locally harvested samples showed a total GLS content about twice as high as populations from the experiment. Conversely, pigments were significantly more abundant in experimental than in local kales, owing to the higher soil fertility. Portuguese samples showed higher phenolic and GLS amounts than Italian and Turkish kales, whereas some of the Italian samples were the richest in carotenoids.CONCLUSIONThis paper represented the first cross‐country comparison of local kale accessions with respect to bioactive compound amounts. Both geographic origin and growing environment appeared to be remarkable and discriminating factors in determining bioactive levels in leafy kales, with possible effects on their health‐promoting and sensorial attributes. © 2013 Society of Chemical Industry
An allotetraploid Brassica napus early‐flowering mutant has BnaFLC2‐regulated flowering
Authors: Huang Yong , Jiang Ling , Ruan Ying , Shen Wenhui , Liu Chunlin 
Published: June 2013

AbstractBACKGROUNDFlowering time is an important agronomic trait, and wide variation in flowering time exists among Brassica napus accessions. GX50 early‐flowering mutant, induced from Brassica napus by Ethyl Methane Sulfonate (EMS), exhibits a remarkable early transition from vegetative to reproductive growth.RESULTSGX50 plants flowered about 60 days earlier than the control wild‐type plant B. napus XY15 under greenhouse conditions. Cytological examination revealed that the GX50 plants form inflorescences as early as from 5 weeks old, flower primordium from 6 weeks old, and siliques from 10 weeks old, whereas 10‐week‐old XY15 plants are still at vegetative growth stage. To unravel the molecular mechanisms underlying the GX50 flowering phenotype, we analyzed the expression of several key regulatory genes. Expressions of all five BnaFLCs (BnaFLC1 to BnaFLC5), BnaFT and BnaSOC1 were detected. Interestingly, BnaFLCs expression levels were lower in GX50 than those in XY15. Among the five BnaFLCs, only the expression pattern of BnaFLC2 corresponded to the timing of floral organ differentiation in GX50. In agreement with previous knowledge that BnaFLCs repress expression of BnaFT and BnaSOC1, increased levels of BnaFT and BnaSOC1 were observed in GX50 compared with XY15.CONCLUSIONBnaFLC2, but not the other BnaFLC genes, plays an important role in B. napus GX50 floral transition. © 2013 Society of Chemical Industry