bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial and temporal dependence of the cerebral endothelial cells elasticity
Authors: Végh Attila G. , Fazakas Csilla , Nagy Krisztina , Wilhelm Imola , Krizbai István A. , Nagyőszi Péter , Szegletes Zsolt , Váró György 
Published: April 2011

AbstractThe reliable determination of the mechanical properties of a living cell is one of the most important challenges of the atomic force microscopic measurements. In the present study the spatial and temporal dependency of the force measurements on cerebral endothelial cells was investigated. Besides imaging the cells, two different sequences of force measurements were applied:

Acquisition of force curves in short time at several points across the cell surface investigating spatial dependence of the elasticity.

Acquisition of force curves for long time at a previously determined place, over the cell nucleus, which provides the temporal stability/variation of the measured forces/values.

Three different stages of endothelial cell cultures of the hCMEC/D3 cells were used: sub‐confluent living, confluent living, and confluent fixed cells. The Young's modulus was calculated from the force curves using the Hertz model and the results were plotted against time or location correspondingly. The rational of using the three stage of culture was to clarify whether the observed effect belongs to the individual cell, to the ensemble of cells or just to some, not living cell component.In case of sub‐confluent cells the results revealed a softer nuclear region compared to the periphery, while an attenuated oscillation like fluctuation in time, with a period of about 10–30 min, was observed.Confluent living cells showed similar tendencies to the sub‐confluent cells, but the changes were larger and the temporal oscillations had longer period. The spatial dependency of the elasticity on confluent cells was confirmed by force–volume measurement too.In case of fixed cells neither spatial nor temporal differences were observed between the nuclear and peripheral region, however the Young's modulus and the error of the measurement was larger, compared to the sub‐confluent living cells. Copyright © 2011 John Wiley & Sons, Ltd.
Analyses of extreme flooding in Austria over the period 1951–2006
Authors: Villarini Gabriele , Smith James A. , Serinaldi Francesco , Ntelekos Alexandros A. , Schwarz Ulrich 
Published: April 2011

AbstractAnalyses of extreme flooding in Austria is performed using daily discharge time series from 27 stations over the period 1951‐2006. The main research questions revolve around: (1) temporal non‐stationarities in the flood record, (2) upper tail and scaling properties of the flood peak records, and (3) relation between magnitude and frequency of flooding and the North Atlantic Oscillation (NAO). Two datasets are derived from the daily discharge time series: annual maximum daily discharge and peaks‐over‐threshold (POT) data. The validity of the stationarity assumption in the annual maximum discharge record is assessed by investigating the presence of abrupt and slowly varying changes using nonparametric tests. The time series are tested for abrupt changes both in the mean and variance of the flood peak distributions by means of the Pettitt test. The presence of monotonic trends is investigated by means of the Mann‐Kendall and Spearman tests. Violations of the stationarity assumption are associated with abrupt rather than gradual changes. These step changes generally involve river regulation through construction of dams or other major engineering works. It is not possible to make conclusive statements about the presence of an anthropogenic climate change signal in the flood peak record. Similar conclusions are obtained when focussing on the frequency of POT floods. The Generalised Extreme Value distribution is used to study the upper tail and scaling properties of annual maximum daily discharge records. The location and scale parameters exhibit power‐law behaviour as a function of drainage area. The shape parameters indicate that the flood peak distributions for Austria have a heavy tail. Non‐stationary modelling of the annual maximum daily discharge and POT time series is used to explore the relation between flood magnitude and frequency and NAO. The results indicate that NAO is a significant covariate in explaining the magnitude and frequency of occurrence of flooding over a large part of Austria. Copyright © 2011 Royal Meteorological Society
Raman imaging and photodegradation study of phthalocyanine containing microcapsules and coated particles
Authors: Bratashov Daniil N. , Masic Admir , Yashchenok Alexey M. , Bedard Matthieu F. , Inozemtseva Olga A. , Gorin Dmitry A. , Basova Tamara , Sievers Torsten K. , Sukhorukov Gleb B. , Winterhalter Mathias , Möhwald Helmuth , Skirtach Andre G. 
Published: April 2011

AbstractWe present the results of using Raman molecular imaging and atomic force microscopy (AFM) investigation of the composition, stability, and photodegradation of polyelectrolyte multilayer microcapsules and coated microparticles containing copper–phthalocyanine and iron–phthalocyanine. The influence of laser light on degradation of these phthalocyanine dyes embedded in the walls of polyelectrolyte multilayer capsules and shells of microparticles was studied by both AFM and Raman molecular imaging, but only the latter technique gave information on dynamics of photodegradation. Raman peak assignment was performed according to theoretical calculations. The degradation rate of phthalocyanine dyes is estimated from Raman signal measurements and a model is proposed to account for the degradation rate. Practical applications of our approach are outlined. Copyright © 2011 John Wiley & Sons, Ltd.
Quick detection of contaminants leaching from polypropylene centrifuge tubes with surface‐enhanced Raman spectroscopy and ultraviolet absorption spectroscopy
Authors: Xu Zhida , Gartia Manas R. , Choi Charles J. , Jiang Jing , Chen Yi , Cunningham Brian T. , Liu Gang Logan 
Published: April 2011

AbstractAnomalous surface‐enhanced Raman scattering (SERS) peaks were identified for liquid sample stored in polypropylene (PP) centrifuge tubes for months. We observed unexpected Raman peaks during experiments with thiamine hydrochloride aqueous solutions stored in PP tubes for 2 months. In order to identify the contaminants, we have performed SERS experiments on deionized (DI) water stored in PP centrifuge tubes for 2 months and compared them with those from fresh DI water sample. We have also carried out ultraviolet (UV) absorption spectra for both fresh and contaminated water. We believe that the water is contaminated because of chemicals leaching from the PP tube. From the gas chromatography‐mass spectrometry data, the main contaminants were found to be phthalic acid (PA) and its derivatives. Further SERS and UV absorption experiment for PA correlated well with the anomalous peaks identified earlier. We qualitatively confirmed the identification and quantitatively estimated the concentration of the suspect contaminants as between 1 and 10 µM with both SERS and UV absorption spectroscopy. With UV absorption spectroscopy, we precisely estimated the concentration as 2.1 µM. We have shown that the sample in PP tube can be contaminated by the leaching chemicals upon long‐term storage, and suggest SERS and UV absorption spectroscopy as two quick and simple techniques to detect the contamination. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of phonon confinement, surface stress, and zirconium doping on the Raman vibrational properties of anatase TiO2 nanoparticles
Authors: Lejon Christian , Österlund Lars 
Published: April 2011

AbstractWe present a comprehensive analysis of the Raman spectra of pure and zirconium‐doped anatase TiO2 nanoparticles. To account for the wavenumber shifts of the Eg(ν6) mode as a function of particle size (L) and dopant concentration (x), a modification of the standard phonon confinement model (PCM) is introduced, which takes into account the contribution of surface stress by means of the Laplace–Young equation. Together with X‐ray diffraction (XRD) and transmission electron microscopy data, our analysis shows that the surface stress contribution to the observed blue shift of the Raman wavenumber is of the same magnitude as the spatial phonon confinement effect. Annealing experiments show that Zr‐doped nanoparticles exhibit retarded grain growth and delayed anatase‐to‐rutile phase transition by up to 200 K compared to pure anatase TiO2. XRD shows that Zr doping leads to a unit cell expansion of the anatase structure. Applying the modified PCM to the x‐dependent variations of the Eg(ν6) Raman mode, the mode‐Grüneisen parameter is found to increase abruptly at x > 0.07 with a concomitant mode softening. This coincides with the x range over which the Zr cations are reported to be displaced from their position in the tetrahedral lattice, and where Zr precipitation occurs upon annealing. The results have implications for the interpretation of Raman spectra of ionic metal oxide nanoparticles and how these are modified upon cation doping. Copyright © 2011 John Wiley & Sons, Ltd.
ARBUSCULAR MYCORRHIZAL FUNGI IN REVEGETATED MINED DUNES
Authors: de Souza R. G. , da Silva D. K. A. , de Mello C. M. A. , Goto B. T. , da Silva F. S. B. , Sampaio E. V. S. B. , Maia L. C. 
Published: April 2011

ABSTRACTThis study aimed to thoroughly investigate communities of arbuscular mycorrhizal fungi (AMF) in six coastal, mined, reconstituted and revegetated dune areas in Northeast Brazil. AMF spore density and species richness as well as the numbers of infective AMF propagules and glomalin‐related soil protein (GRSP) were analyzed. Four areas had been restored for 16, 12, 8 and 4 years, and after being mined, reconstituted and re‐vegetated, the fifth was mined and reconstituted but not yet re‐vegetated, and the sixth had a native and undisturbed coastal forest vegetation. The soil samples were sampled in the dry and wet seasons of 2005. The number of infective propagules was significantly higher in the dry than in wet season, except in the un‐vegetated dune area, which had less than 0·2 propagules cm−3 soil. AMF spore density and especially GRSP contents changed little between the seasons. GRSP contents were positively correlated to Al and Fe soil levels and were highest in the restinga forest. In total, 29 AMF species were identified, and glomoid and gigasporoid species predominated in all areas. AMF species richness and viable propagules of AMF were lowest in the un‐vegetated dune area. Remarkably, higher species richness (28) was found in the re‐vegetated areas, compared with the forest area that had only 10 species. The numbers of infective propagules tended to be also lower in the forest than in the re‐vegetated sites. In conclusion, re‐vegetation appears to favour the AMF communities in terms of infective propagule numbers and AMF species richness. Copyright © 2011 John Wiley & Sons, Ltd.
Synergistic effect of diisopropyl phosphite and over‐based calcium sulphonate additives on tribological properties of AISI 52100 steel/Al2O3 ceramics
Authors: Jiang Shuyun , Xie Hongjun 
Published: April 2011

ABSTRACTThe friction‐reducing and anti‐wear effect of the 500SN base oil containing diisopropyl phosphite (T451) and over‐based calcium sulphonate (KT5447) on AISI 52100 steel/Al2O3 ceramic were investigated with a ball‐on‐disc tribometer at a light load of 200 N and a high load of 400 N. The results indicate that the 500SN base oil containing T451 and KT5447 appears to have a synergistic effect on the pair. For the light load of 200 N, the effective composition is 3 wt% T451 + 2–3 wt% KT5447. For the high load of 400 N, the combination of T451 and KT5447 appears to have a synergistic friction‐reducing and anti‐wear effect. The scanning electron microscope images show that ploughed grooves, pitting, spalling and corrosion are the dominant wear modes for both 200 and 400 N. However, no evidence for the formation of the expected sulphur‐containing or phosphorus‐containing chemical compound is found according to X‐ray photoelectron spectroscopy analysis of the worn steel ball surface at both loads. Copyright © 2011 John Wiley & Sons, Ltd.
The effects of a demulsifier on the interface of marine engine oil and water
Authors: Lu Ya , Chen Xiaoxu 
Published: April 2011

ABSTRACTThe water‐shedding property and the interfacial tension of marine engine oils with various additives have been assessed and analysed in this paper. It is concluded that the weak water‐shedding property was mainly due to the molecular structure and the interfacial property of sulphonate detergent, which can adsorb on the oil–water interface intensely to form a strong interfacial film and prevent coalescence of droplets. The impact of a demulsifier to the water‐shedding property and the interfacial tension indicated that demulsifier improved the water‐shedding property of marine engine oil in the manner of being much easy to adsorb onto the interface but formatting a flimsy interfacial film. Copyright © 2011 John Wiley & Sons, Ltd.
A prospective, randomized controlled trial on the efficacy of fractional photothermolysis on scar remodeling
Authors: Lin Jennifer Y. , Warger William C. , Izikson Leonid , Anderson R. Rox , Tannous Zeina 
Published: April 2011

AbstractBackgroundNon‐ablative fractional resurfacing (NAFR) has been reported in case studies as an effective treatment for surgical and burn scars [Behroozan et al., J Cosmet Laser Ther 2006; 8(1):35–38; Haedersdal et al., Lasers Surg Med 2009; 41(3):189–195; Waibel and Beer, J Drugs Dermatol 2008; 7(1):59–61; Niwa et al., Dermatol Surg 2009; 35(5):773–777; discussion 777–778; and Tierney et al., Dermatol Surg 2009; 35(8):1172–1180]. We have performed a prospective, randomized controlled study with two different treatment arms to better characterize the response of hypertrophic scars to NAFR.Study DesignWe conducted a prospective, controlled trial on linear, surgical hypertrophic scars 6 months or older in age. Subjects were randomized into two treatment arms of NAFR: (a) high‐density treatment arm (HDTA): 40 mJ and percent coverage of 26% and (b) low‐density treatment arm (LDTA): 40 mJ and percent coverage of 14%. One‐half of the scar was treated every 2 weeks for a total of four treatments, with subsequent follow‐up visits at 1 month and 3 months. Scar improvement was judged as compared to the untreated side by the subjects and two blinded observers using a four‐point scale (0 = no improvement or worsening, 1 = minor improvement, 2 = moderate improvement, and 3 = marked improvement). Volumetric changes were also measured for a select group (n = 4) by measuring scar casts with optical frequency domain imaging. Patient satisfaction was surveyed at the end of the trial. Side effects in both treatment arms were assessed.ResultsTwenty patients were enrolled, of which 17 subjects noted improvement in their scars compared to untreated side. Three subjects in the HDTA rated their scars as having a worsened appearance at the end of the study. After treatment was completed, scars continued to improve in appearance at 3 months compared to 1 month. Subjects in the LDTA rated the treated side with higher scores, than subjects in the HDTA (P = 0.001). Scars <2 years old tended to respond better to NAFR as compared to scars >6 years old. The side effects profile was more severe in the HDTA group. Nevertheless, all subjects were satisfied with the procedure at trial completion.ConclusionsThis study demonstrates the efficacy of NAFR for treating hypertrophic scars. Low‐density treatment is at least as effective as the high‐density treatment and with fewer side effects. The study also suggests that younger scars respond better to NAFR. Thus, early intervention may be key in the treatment of hypertrophic scars. Lasers Surg. Med. 43:265–272, 2011. © 2011 Wiley‐Liss, Inc.
Neuron Cells Uptake of Polymeric Microcapsules and Subsequent Intracellular Release
Authors: Pavlov Anton M. , Sapelkin Andrei V. , Huang Xinyue , P'ng Ken M. Y. , Bushby Andy J. , Sukhorukov Gleb B. , Skirtach André G. 
Published: April 2011

AbstractNeuron cells uptake of biodegradable and synthetic polymeric microcapsules functionalized with aggregates of gold nanoparticles incorporated into their shells is demonstrated in situ. In addition to traditionally used optical microscopy, electron microscopy is used both for higher‐resolution imaging and for confirming the uptake by focused ion beam cross‐sectioning of specific cells in situ. Subsequently, physical methods of release are compared to chemical methods wherein laser‐induced intracellular release of dextran molecules into the cytosol of hippocampal neuron cells is studied in comparison to biodegradation. Implications of this work for neuroscience, bio‐medicine and single cell studies are discussed. magnified image
Microgels for the Encapsulation and Stimulus‐Responsive Release of Molecules with Distinct Polarities
Authors: Jagadeesan Dinesh , Nasimova Irina , Gourevich Ilya , Starodubtsev Sergey , Kumacheva Eugenia 
Published: April 2011

AbstractA microfluidic strategy for the encapsulation and stimulus‐responsive release of molecules with distinct polarities from the interior of microgels is reported. The approach relies on (i) the generation of a primary O/W emulsion by the ultrasonication method, (ii) MF emulsification of the primary emulsion, and (iii) photopolymerization of the monomer present in the aqueous phase of the droplets, thereby transforming them into microgels. Non‐polar molecules are dissolved in oil droplets embedded in the microgels. Polar molecules are physically associated with the hydrogel network. Upon heating, the microgels contract and release polar and non‐polar cargo molecules. The approach paves the way for stimuli‐responsive vehicles for multiple drug delivery. magnified image
A new steel with good low‐temperature sulfuric acid dew point corrosion resistance
Authors: Cheng X. Q. , Sun F. L. , Lv S. J. , Li X. G. 
Published: April 2011

AbstractIn this work, new steels (1#, 2#, and 3#) were developed for low‐temperature sulfuric acid dew point corrosion. The mass loss rate, macro‐ and micro‐morphologies and compositions of corrosion products of new steels in 10, 30, and 50% H2SO4 solutions at its corresponding dew points were investigated by immersion test, scanning electron microscopy (SEM) and energy‐dispersive spectrometry (EDS). The results indicated that mass loss rate of all the tested steels first strongly increased and then decreased as H2SO4 concentration increased, which reached maximum at 30%. Corrosion resistance of 2# steel is the best among all specimens due to its fine and homogeneous morphologies of corrosion products. The electrochemical corrosion properties of new steels in 10 and 30% H2SO4 solutions at its corresponding dew points were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that corrosion resistance of 2# steel is the best among all the experimental samples due to its lowest corrosion current density and highest charge transfer resistance, which is consistent with the results obtained from immersion tests.
Four‐dimensional visualisation and analysis of protein–protein interaction networks
Authors: Goel Apurv , Li Simone S. , Wilkins Marc R. 
Published: April 2011

AbstractProtein–protein interaction networks are typically built with interactions collated from many experiments. These networks are thus composite and show all interactions that are currently known to occur in a cell. However, these representations are static and ignore the constant changes in protein–protein interactions. Here we present software for the generation and analysis of dynamic, four‐dimensional (4‐D) protein interaction networks. In this, time‐course‐derived abundance data are mapped onto three‐dimensional networks to generate network movies. These networks can be navigated, manipulated and queried in real time. Two types of dynamic networks can be generated: a 4‐D network that maps expression data onto protein nodes and one that employs ‘real‐time rendering’ by which protein nodes and their interactions appear and disappear in association with temporal changes in expression data. We illustrate the utility of this software by the analysis of singlish interface date hub interactions during the yeast cell cycle. In this, we show that proteins MLC1 and YPT52 show strict temporal control of when their interaction partners are expressed. Since these proteins have one and two interaction interfaces, respectively, it suggests that temporal control of gene expression may be used to limit competition at the interaction interfaces of some hub proteins. The software and movies of the 4‐D networks are available at http://www.systemsbiology.org.au/downloads_geomi.html.
Quantitative evaluation of refolding conditions for a disulfide‐bond‐containing protein using a concise 18O‐labeling technique
Authors: Uchimura Hiromasa , Kim Yusam , Mizuguchi Takaaki , Kiso Yoshiaki , Saito Kazuki 
Published: April 2011

AbstractA concise method was developed for quantifying native disulfide‐bond formation in proteins using isotopically labeled internal standards, which were easily prepared with proteolytic 18O‐labeling. As the method has much higher throughput to estimate the amounts of fragments possessing native disulfide arrangements by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) than the conventional high performance liquid chromatography (HPLC) analyses, it allows many different experimental conditions to be assessed in a short time. The method was applied to refolding experiments of a recombinant neuregulin 1‐β1 EGF‐like motif (NRG1‐β1), and the optimum conditions for preparing native NRG1‐β1 were obtained by quantitative comparisons. Protein disulfide isomerase (PDI) was most effective at the reduced/oxidized glutathione ratio of 2:1 for refolding the denatured sample NRG1‐β1 with the native disulfide bonds.
Electrostatic force microscopy of self‐assembled peptide structures
Authors: Clausen Casper Hyttel , Dimaki Maria , Panagos Spyros Pantoleon , Kasotakis Emmanouil , Mitraki Anna , Svendsen Winnie Edith , Castillo‐León Jaime 
Published: April 2011

AbstractIn this report electrostatic force microscopy (EFM) is used to study different peptide self‐assembled structures such as tubes and particles. It is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures. In particular we use EFM to investigate the structures of diphenylalanine peptide tubes, particles, and CSGAITIG peptide particles placed on pre‐fabricated SiO2 surfaces with a backgate. We show that the cavity in the peptide tubes could be due to the presence of water residues. Additionally we show that self‐assembled amyloid peptides form spherical solid structures containing the same self‐assembled peptide in its interior. In both cases transmission electron microscopy is used to verify these structures. Further, the limitations of the EFM technique are discussed, especially when the observed structures become small compared with the radius of the AFM tip used. Finally, an agreement between the detected signal and the structure of the hollow peptide tubes is demonstrated. SCANNING 33: 201–207, 2011. © 2011 Wiley Periodicals, Inc.