bluuebunny/crossref_metadata_2025_split huggingface dataset:
VEGF‐incorporated biomimetic poly(lactide‐co‐glycolide) sintered microsphere scaffolds for bone tissue engineering
Authors: Jabbarzadeh Ehsan , Deng Meng , Lv Qing , Jiang Tao , Khan Yusuf M. , Nair Lakshmi S. , Laurencin Cato T. 
Published: August 2012

AbstractRegenerative engineering approaches utilizing biomimetic synthetic scaffolds provide alternative strategies to repair and restore damaged bone. The efficacy of the scaffolds for functional bone regeneration critically depends on their ability to induce and support vascular infiltration. In the present study, three‐dimensional (3D) biomimetic poly(lactide‐co‐glycolide) (PLAGA) sintered microsphere scaffolds were developed by sintering together PLAGA microspheres followed by nucleation of minerals in a simulated body fluid. Further, the angiogenic potential of vascular endothelial growth factor (VEGF)‐incorporated mineralized PLAGA scaffolds were examined by monitoring the growth and phenotypic expression of endothelial cells on scaffolds. Scanning electron microscopy micrographs confirmed the growth of bone‐like mineral layers on the surface of microspheres. The mineralized PLAGA scaffolds possessed interconnectivity and a compressive modulus of 402 ± 61 MPa and compressive strength of 14.6 ± 2.9 MPa. Mineralized scaffolds supported the attachment and growth and normal phenotypic expression of endothelial cells. Further, precipitation of apatite layer on PLAGA scaffolds resulted in an enhanced VEGF adsorption and prolonged release compared to nonmineralized PLAGA and, thus, a significant increase in endothelial cell proliferation. Together, these results demonstrated the potential of VEGF‐incorporated biomimetic PLAGA sintered microsphere scaffolds for bone tissue engineering as they possess the combined effects of osteointegrativity and angiogenesis. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Variability and trends of heating degree‐days in Argentina
Authors: Castañeda M. Elizabeth , Claus Federico 
Published: August 2012

AbstractThis study analyses heating degree‐days (HDDs) in Argentina during the period 1900–2008. Gridded temperature data provided by the University of Delaware were analysed to calculate monthly and annual cumulative HDDs. Mean, maximum and minimum values as well as the average duration of the heating season are used to characterize the mean features of the region. Spatial variations are driven by latitude and altitude. The analysis of the temporal distribution of HDDs reveals that the centre of the mean heating season varies from mid‐June to mid‐July. The length of the cold season grows with increasing latitude and westward with increasing altitude. In the high Andes, the heating season extends all year round. S‐mode principal component analysis is used to identify sub‐groups of grid points with similar temporal variability. Negative trends in annual cumulative HDDs are detected in most of the country. Linear and nonlinear trends as well as temporal statistics are examined for inter‐ and intra‐annual variability of HDDs to discuss its potential incidence on residential use of natural gas. Seasonal increases in natural gas consumption in the country, including the effect of regional price benefits, could be now better explained not only by population growth but also by the spatial and temporal characterization of the HDD season.
Intervertebral disc degeneration and ectopic bone formation in apolipoprotein E knockout mice
Authors: Zhang Dawei , Jin Li , Reames Davis L. , Shen Francis H. , Shimer Adam L. , Li Xudong 
Published: August 2012

AbstractCardiovascular risk factors are known to be associated with intervertebral disc degeneration, but the underlying mechanism is still unclear. The ApoE knockout (KO) mouse is a well‐established model for atheroscelorosis. We hypothesized that ApoE is involved in maintaining disc health and that ApoE KO mice will develop early disc degeneration. Discs of ApoE KO and wild‐type (WT) mice were characterized with histological/immunological, biochemical, and real‐time RT‐PCR assays. A comparison of the extracellular matrix production was also performed in disc cells. We demonstrated that ApoE was highly expressed in the endplates of WT discs, and ectopic bone formed in the endplates of ApoE KO discs. Glycosaminoglycan content was decreased in both ApoE KO annulus fibrosus (AF) and nucleus pulposus (NP) cells. Collagen levels were increased in AF and decreased in NP cells. Matrix metalloproteinase‐3, ‐9, and ‐13 expressions were increased, which may partially explain the impaired matrix production. We also found collagen I, II, aggrecan, and biglycan mRNA expressions were increased in AF cells but decreased in NP cells. Apoptosis was increased in the ApoE KO NP tissue. These results suggest early disc degeneration changes in the ApoE KO mice. ApoE may play a critical role in disc integrity and function. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 210–217, 2013
Can rapidly accumulating Holocene peat profiles provide sub‐decadal resolution proxy climate data?
Authors: Amesbury Matthew J. , Barber Keith E. , Hughes Paul D. M. 
Published: August 2012

AbstractTo test the potential for developing sub‐decadal resolution records of ombrotrophic bog surface wetness (BSW), selected abrupt climate events were identified in cores from four sites in north‐west Europe and time‐slices over each event were investigated at 2–5‐mm resolution using peat humification, testate amoeba and plant macrofossil analyses. Age–depth models based on radiocarbon, spheroidal carbonaceous particle and tephra dates were applied and the error in these models was used to determine the effective temporal sampling resolution, which in most cases was sub‐decadal. Fine‐resolution results revealed some inconsistencies in the co‐variability of individual proxies and there was a lack of correspondence between some results from adjacent cores. However, we found evidence of abrupt shifts in BSW occurring over ca. 5–20 years, indicating a more rapid proxy response than identified in previous research. To maximize potential temporal resolution and produce reliable sub‐decadal BSW data in future research, we recommended that peat‐based studies should obtain the best possible chronological control, focus on sites with high species diversity and rapid accumulation rates and perform replicate coring, or use open peat sections where the stratigraphy can be clearly seen, to assess intra‐site differences in microtopography. Site‐specific factors should be a primary consideration in the selection of sites for future fine‐resolution research. Copyright © 2012 John Wiley & Sons, Ltd.
Fluctuations in the late Quaternary East Asian winter monsoon recorded in sediment records of surface water cooling in the northern Japan Sea
Authors: Ikehara Ken , Fujine Kazuho 
Published: August 2012

AbstractThe East Asian monsoon climate system involves interactions between land and ocean and is composed of summer and winter monsoons. Cooling of surface water by the East Asian winter monsoon (EAWM) promotes the formation of sea ice and deep water in the northern Japan Sea. Modern observations suggest close relationships between intensification of the EAWM and both sea ice formation and sea‐surface temperature (SST) decrease in the northeastern Japan Sea. Records of ice‐rafted debris (IRD) and alkenone‐based SST in the northeastern Japan Sea are examined to clarify the temporal variability of the EAWM and its controlling factors. Close relationships with oxygen isotope records of Chinese stalagmites and Northern Hemisphere summer insolation are observed in the records of IRD occurrence and SST during Marine Isotope Stages (MIS) 3–5. The co‐occurrence of maxima in the abundance of IRD and minima in SST in the northeastern Japan Sea indicates that the intensity of the EAWM was enhanced during periods of low summer insolation and high oxygen isotope ratios in Chinese stalagmites. Decoupling between the IRD and SST records during MIS 2 and MIS 6 might be the result of differences in surface water conditions caused by low sea levels and the resultant closure of the Tsushima Strait. During MIS 3 and 4, some small but clear maxima in IRD and minima in SST occurred at relatively low summer insolation periods. Some of these peaks co‐occur with North Atlantic Heinrich events, suggesting a possible climate linkage between the North Atlantic and the Asian monsoon. The presence of finer fluctuations in the occurrence of IRD than in summer insolation suggests finer millennial–centurial timescale fluctuations in the intensity of the EAWM. Furthermore, some IRD peaks occurred during periods of high insolation, such as 39, 86, 103, 128, 145, and 153 ka. Some of these IRD peaks correlate with minima in reconstructed SST and maxima in oxygen isotope ratios of Chinese stalagmites. This result suggests that extremely cold winters occur even during periods of enhanced East Asian summer monsoon intensity, and indicates that solar insolation is not the only factor that controls variations in the intensity of the EAWM at millennial–centurial timescales. Copyright © 2012 John Wiley & Sons, Ltd.
Interaction with an autostereoscopic touch screen: effect of occlusion on subjective experiences when pointing to targets in planes of different depths
Authors: Pölönen Monika , Järvenpää Toni , Salmimaa Marja 
Published: August 2012

AbstractIt is well known that the usability of a typical touch screen depends on several parameters, including interface design, device characteristics, and input operations. However, there is virtually no knowledge regarding how people evaluate interaction with 3D display‐integrated touch screen. Twenty‐one participants were asked to use standard touch screen to point to targets in planes of different planes on an autostereoscopic display and evaluate how natural and easy this action was. Clear differences in pointing experiences across depth levels and input operators were found. Pointing to targets in a back plane was reported to be more natural and easier than the same action with targets in a front plane. The use of finger input was less unnatural than the use of a stylus, but the use of stylus with icons in the front plane was more fun and entertaining.
Influence of the topology of an artificial neural network on the results for estimating the cyclic material properties
Authors: el Dsoki C. , Lohmann F. , Hanselka H. , Kaufmann H. 
Published: August 2012

AbstractZur Abschätzung der Lebensdauer von zyklisch belasteten Bauteilen anhand statischer Werkstoffkennwerte existieren zahlreiche Abschätzungsverfahren, die größtenteils auf empirischen Gleichungen beruhen. Mit zunehmender Anzahl der Eingabe‐ und Einflussparameter steigt auch der Aufwand zur Ableitung dieser Gleichungen und die Abschätzungsgenauigkeit sinkt. Daher wurde nach neuartigen Methoden gesucht, um die zyklischen Kennwerte zuverlässig abschätzen zu können. Ein vielversprechender Ansatz ist mit den künstlich neuronalen Netzen gefunden worden, welche den Zusammenhang zwischen Eingangsparametern und Ausgabeparametern selbst erschließen können. Als Eingangsparameter kommen die statischen Kennwerte der zu untersuchenden Werkstoffe zum Einsatz, da diese gegenüber den zyklischen schneller und kostengünstiger zu ermitteln sind. Als Ausgabegrößen werden die zyklischen Kennwerte der Ramberg‐Osgood‐ und der Manson‐Coffin‐Basquin‐Gleichung abgeschätzt. Die künstlich neuronalen Netze können dabei sehr unterschiedlich und beliebig komplex aufgebaut sein. In dieser Arbeit wird der Einfluss der Verknüpfungen der Neuronen untereinander, der sogenannten Topologie, auf die Abschätzungsgüte der künstlich neuronalen Netze untersucht. Ausgehend von einem Referenzfall wird gezeigt, dass komplexere Topologien demgegenüber nicht die gewünschten Verbesserungen bei der Abschätzung der zyklischen Kennwerte erzielen.
The influence of the surface finishing on the electrochemical behaviour of austenitic and superaustenitic steels
Authors: Alar V. , Baršić G. , Runje B. , Alar Ž. 
Published: August 2012

AbstractThe influence of surface roughness on the pitting potential and the corrosion potential of the DIN W.Nr. 1.4541 and DIN W.Nr 1.4465 stainless steels were examined using electrochemical techniques. Roughness and electrochemical tests were performed on samples with various surface finishing. Electrochemical studies were conducted in an electrochemical cell where steel electrodes were immersed in 0.1 M NaCl and 0.1 M NaCl + 0.1 M Na2SO4 aqueous solutions. We found for both materials when immersed in 0.1 M NaCl aqueous solution lower pitting potential than in 0.1 M NaCl + 0.1 M Na2SO4. The results showed that the electrochemical behaviour of the DIN W.Nr. 1.4465 is better than of DIN W.Nr. 1.4541.
Hyperhydrophilic rough surfaces and imaginary contact angles
Authors: Jennissen H. P. 
Published: August 2012

AbstractThe complete wetting of rough surfaces is only poorly understood, since the underlying phenomena can neither be described by the Cassie‐Baxter nor the Wenzel equation. An experimental accessiblility by the sessile drop method is also very limited. The term “superhydrophilicity” was an attempt to understand the wetting of rough surfaces, but a clear definition is still forthcoming, mainly because non‐superhydrophilic surfaces can also display a contact angle of zero. Since the Wilhelmy balance is based on force measurements, it offers a technology for obtaining signals during the whole wetting process. We have obtained evidence that additional forces occur during the complete wetting of rough surfaces and that mathematically contact angles for a hydrophilicity beyond the contact angle of zero can be defined by imaginary numbers. A hydrophilized TPS‐surface obtained by chemical wettability switching from a superhydrophobic surface has been previously characterized by dynamic imaginary contact angles of 20i°–21i° and near‐zero hysteresis. Here an extremely high wetting rate is demonstrated reaching a virtual imaginary contact angle of ΘV,Adv > 3.5i° in less than 210 ms. For a rough surface displaying imaginary contact angles and extremely high wetting rates we suggest the term hyperhydrophilicity. Although, as will be shown, the physical basis of imaginary contact angles is still unclear, they significantly expand our methodology, the range of wettability measurements and the tools for analyzing rough hydrophilic surfaces. They may also form the basis for a new generation of rationally constructed medicinal surfaces.
One component? Two components? Three? The effect of including a nonexchanging “free” water component in multicomponent driven equilibrium single pulse observation of T1 and T2
Authors: Deoni Sean C. L. , Matthews Lucy , Kolind Shannon H. 
Published: August 2012

AbstractQuantitative myelin content imaging provides novel and pertinent information related to underlying pathogenetic mechanisms of myelin‐related disease or disorders arising from aberrant connectivity. Multicomponent driven equilibrium single pulse observation of T1 and T2 is a time‐efficient multicomponent relaxation analysis technique that provides estimates of the myelin water fraction, a surrogate measure of myelin volume. Unfortunately, multicomponent driven equilibrium single pulse observation of T1 and T2 relies on a two water‐pool model (myelin‐associated water and intra/extracellular water), which is inadequate within partial volume voxels, i.e., containing brain tissue and ventricle or meninges, resulting in myelin water fraction underestimation. To address this, a third, nonexchanging “free‐water” component was introduced to the multicomponent driven equilibrium single pulse observation of T1 and T2 model. Numerical simulations and experimental in vivo data show that the model to perform advantageously within partial volume regions while providing robust and reproducible results. It is concluded that this model is preferable for future studies and analysis. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Hospitalisation for infection prior to diagnosis of acute lymphoblastic leukaemia in children
Authors: Vestergaard Therese Risom , Rostgaard Klaus , Grau Katrine , Schmiegelow Kjeld , Hjalgrim Henrik 
Published: August 2012

AbstractBackgroundIt has been proposed that infections in infancy and early childhood are associated with a reduced risk of childhood acute lymphoblastic leukaemia (ALL). We tested this hypothesis in a register‐based study of hospitalisations for infectious diseases prior to diagnosis of childhood ALL.ProcedureA nation‐wide cohort encompassing all Danish children aged 0–14 years and born between 1977 and 2008 (N = 1,778,129) was established and followed for hospitalisations for infectious diseases and risk of childhood ALL. The exposure was lagged 1 year to limit reverse causality. In the statistical analyses exposure was defined as (time dependent) number of early or late (before 2 or at/after 2 years of age) hospitalisations to further explore possible age‐dependent associations.ResultsA total of 815 children were diagnosed with ALL during follow‐up. Risk of ALL was associated neither with hospitalisations for infectious diseases before (incidence rate ratio = 0.92, 95% confidence interval 0.78–1.07) nor at/after 2 years of age (incidence rate ratio = 1.04, 95% confidence interval 0.81–1.32). This also applied to subsets of ALL supposedly initiated prenatally.ConclusionThe absence of association between hospitalisation for infections and risk of childhood ALL directs future investigations of the role of infections in development of childhood ALL towards exploration of less severe infections. Pediatr Blood Cancer 2013; 60: 428–432. © 2012 Wiley Periodicals, Inc.
Super‐atom properties of 13 atom clusters of group 13 elements
Authors: Varns Rebecca , Strange Paul 
Published: August 2012

AbstractWe report first principles calculations of the geometry and electronic structure of 13 atom clusters of boron, aluminium, gallium and indium. These density functional theory calculations support the jellium model in the energy levels and molecular orbitals of the cluster and enable us to discuss the relevance of the superatom concept. We go on to examine a number of cluster symmetries in detail as a function of charge and comment on the successes and limitations of the jellium and superatom models in describing these clusters. In particular we find that the monovalent anionic cluster is the most stable and has the most symmetric structure. As charge changes the symmetry of the clusters decreases in a way that is dependent on symmetry and charge, but not atomic species.
Spin in density‐functional theory
Authors: Jacob Christoph R. , Reiher Markus 
Published: August 2012

AbstractThe accurate description of open‐shell molecules, in particular of transition metal complexes and clusters, is still an important challenge for quantum chemistry. Although density‐functional theory (DFT) is widely applied in this area, the sometimes severe limitations of its currently available approximate realizations often preclude its application as a predictive theory. Here, we review the foundations of DFT applied to open‐shell systems, both within the nonrelativistic and the relativistic framework. In particular, we provide an in‐depth discussion of the exact theory, with a focus on the role of the spin density and possibilities for targeting specific spin states. It turns out that different options exist for setting up Kohn–Sham DFT schemes for open‐shell systems, which imply different definitions of the exchange–correlation energy functional and lead to different exact conditions on this functional. Finally, we suggest possible directions for future developments. © 2012 Wiley Periodicals, Inc.
Simulation of FIB‐SEM Images for Analysis of Porous Microstructures
Authors: Prill Torben , Schladitz Katja 
Published: August 2012

SummaryFocused ion beam nanotomography‐scanning electron microscopy tomography yields high‐quality three‐dimensional images of materials microstructures at the nanometer scale combining serial sectioning using a focused ion beam with SEM. However, FIB‐SEM tomography of highly porous media leads to shine‐through artifacts preventing automatic segmentation of the solid component. We simulate the SEM process in order to generate synthetic FIB‐SEM image data for developing and validating segmentation methods. Monte‐Carlo techniques yield accurate results, but are too slow for the simulation of FIB‐SEM tomography requiring hundreds of SEM images for one dataset alone. Nevertheless, a quasi‐analytic description of the specimen and various acceleration techniques, including a track compression algorithm and an acceleration for the simulation of secondary electrons, cut down the computing time by orders of magnitude, allowing for the first time to simulate FIB‐SEM tomography. SCANNING 35: 189‐195, 2013. © 2012 Wiley Periodicals, Inc.
Skill relatedness and firm diversification
Authors: Neffke Frank , Henning Martin 
Published: August 2012

AbstractBecause of the importance of human capital, a firm's choice of diversification targets will depend on whether these targets offer opportunities for leveraging existing human resources. We propose to quantify the similarity of different industries' human capital or skill requirements, that is, the industries' skill relatedness, by using information on cross‐industry labor flows. Labor flows among industries can be used to identify skill relatedness, because individuals changing jobs will likely remain in industries that value the skills associated with their previous work. Estimates show that firms are far more likely to diversify into industries that have ties to the firms' core activities in terms of our skill‐relatedness measure than into industries without such ties or into industries that are linked by value chain linkages or by classification‐based relatedness. Copyright © 2012 John Wiley & Sons, Ltd.
Three‐Dimensional Gold Nanoparticle Clusters with Tunable Cores Templated by a Viral Protein Scaffold
Authors: Li Feng , Chen Huiling , Zhang Yejun , Chen Zhong , Zhang Zhi‐Ping , Zhang Xian‐En , Wang Qiangbin 
Published: August 2012

AbstractAssembling nanoparticles (NPs) into ordered architectures remains a challenge in the field of nanotechnology. Templated strategies have been widely utilized for NP assembly. As typical biological nanostructures, virus‐based NPs (VNPs) have shown great promise in templating NP assembly. Here it is illustrated that the VNP of simian virus 40 (SV40) is a powerful scaffold in directing the assembly of 3D hybrid nanoarchitectures with one NP encapsulated inside as a core and a cluster of gold NPs (AuNPs) on the outer surface of the SV40 VNP as a shell, in which the core NPs can be CdSe/ZnS quantum dots (QDs), Ag2S QDs, or AuNPs. The assembling of AuNPs onto the SV40 VNP surface is determined by the interactions between the AuNPs and the amine groups on the outer surface of SV40 VNPs. It is expected that the VNP guided 3D hybrid nanoarchitectures provide ideal models for NP interaction studies and open new opportunities for integrating various functionalities in NP assemblies.
A New Method of Rail Head Hardening of Standard‐Gauge Rails for Improved Wear and Damage Resistance
Authors: Kuziak Roman , Zygmunt Tomasz 
Published: August 2012

AbstractA new method of cyclic‐accelerated cooling of the head of pearlitic rails to increase their performance in service was described in this paper. It is essentially based upon the head's immersion in aqueous polymer solution. However, as opposed to the methods developed so far, the head's immersion is performed cyclically by raising and lowering the level of the cooling solution, dividing the entire process into fast and slow cooling stages. When the intervals of the fast and slow cooling stages are properly defined, there is no necessity to control the time of the entire process to prevent the bainite/martensite formation. The most important effect of the cyclic cooling is that the entire time of the process can be adjusted to obtain fine pearlitic structure in the whole cross‐section of the head. Applying this technology, the head hardened rails were produced at Huta Królewska S.A. and tested successfully in track.