bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photobleaching in Two‐Photon Scanning Fluorescence Correlation Spectroscopy
Authors: Petrášek Zdeněk , Schwille Petra 
Published: December 2007

AbstractTwo‐photon excitation in fluorescence correlation spectroscopy (FCS) is often preferred to one‐photon excitation because of reduced bulk photobleaching and photodamage, and deeper penetration into scattering media, such as thick biological specimens. Two‐photon FCS, however, suffers from lower signal‐to‐noise ratios which are directly related to the lower molecular brightness achieved. We compare standard FCS with a fixed measurement volume with scanning FCS, where the measurement volume is scanned along a circular path. The experimental results show that photobleaching is the dominant cause of the effects observed at the high excitation powers necessary for good signal‐to‐noise ratios. Theoretical calculations assuming a nonuniform excitation intensity profile, and using the concept of generalized volume contrast, provide an explanation for the photobleaching effects commonly observed in two‐photon FCS at high excitation intensities, without having to assume optical saturation. Scanning alleviates these effects by spreading the photobleaching dose over a larger area, thereby reducing the depletion of fluorescent molecules in the measurement volume. These results, which facilitate understanding of the photobleaching in FCS and of the positive effects of scanning, are particularly important in studies involving the autocorrelation amplitude g(0), such as concentration measurements or binding studies using fluorescence cross‐correlation between two labeled species.
Electrical and Optical Properties of Cetineite‐Type Rb‐, Sr‐, and Ba‐Oxoselenoantimonates(III)
Authors: Sendor Dorota , Fokwa Boniface P. T. , Dronskowski Richard , Simon Ulrich 
Published: December 2007

AbstractLarge single‐crystals of the cetineite‐type phases (Rb;Se), (Sr;Se) and (Ba;Se) have been synthesized by hydrothermal reactions and single‐crystal X‐ray analyses with atomic resolution together with the electrical and optical measurements confirm a trend in the optical gap related to the chemical composition. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Pyrazole‐Bridged NHC Ligands and Their Dimetallic (Allyl)palladium Complexes
Authors: Scheele Ulrich J. , John Michael , Dechert Sebastian , Meyer Franc 
Published: December 2007

AbstractA set of compartmental pyrazole‐based ligands with appended NHC donors has been synthesized and isolated as [H4L]Cl3 and [H3L](PF6)2 salts. Dinuclear (allyl)palladium complexes of these ligands are conveniently accessible via the in situ prepared silver species. Three complexes [(allyl)2Pd2L]PF6 and one derivative [(methallyl)2Pd2L]PF6 have been characterized crystallographically, which revealed that the metal ions are positioned in close proximity [d(Pd···Pd) = 3.97–4.05 Å], with two possible mutual orientations of the (meth)allyl ligands within the dimetallic pocket. NMR spectroscopy shows slow interconversion of these isomers (k = 0.05–0.4 s–1), where the (meth)allyl ligands are detached trans to the carbene during this η3‐η1‐η3 dynamic process.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Microfluidic chip‐based cell electrophoresis with multipoint laser‐induced fluorescence detection system
Authors: Yu Linfen , Shen Zheng , Mo Jiankun , Dong Xiuling , Qin Jianhua , Lin Bingcheng 
Published: December 2007

AbstractIn this work, the electrophoretic mobility (EPM) measurement of individual cells was investigated by a simple on‐chip electrophoresis system with LIF multipoint detection. The system enabled the characterization of cell electrophoresis behavior as well as the fluorescence signal from individual cells simultaneously. The measurement yielded the electropherograms of a large number of cells labeled with dye, in which the migration time and migration distance could be obtained easily. The EPM has been demonstrated to be different between the K562 cells and K562 cells treated with anticancer drug arsenic trioxide (As2O3). The K562 cells were found to exhibit a lower EPM compared to the cells after drug addition with different concentration. In this preliminary study, over 300 cells could be analyzed within 2 h, demonstrated a much higher analysis throughput compared with traditional methods. The established system is simple and fast, which is expected to be a promising method for evaluating cell surface properties and to be useful in clinical and pharmaceutical applications.
Electrodeless direct current dielectrophoresis using reconfigurable field‐shaping oil barriers
Authors: Thwar Prasanna K. , Linderman Jennifer J. , Burns Mark A. 
Published: December 2007

AbstractWe demonstrate dielectrophoretic (DEP) potential wells using pairs of insulating oil menisci to shape the DC electric field. These oil menisci are arranged in a configuration similar to the quadrupolar electrodes, typically used in DEP, and are shown to produce similar field gradients. While the one‐pair well produces a focusing effect on particles in flow, the two‐pair well results in creating spatial traps against crossflows. Uncharged polystyrene particles were used to map the DEP force fields and the experimental observations were compared against the field profiles obtained by numerically solving Maxwell's equations. We demonstrate trapping of a single particle due to negative DEP against a pressure‐driven crossflow. This can be easily extended to trap and hold cells and other objects against flow for a longer time. We also show the results of particle trapping experiments performed to observe the effect of adjusting the oil menisci and the gap between two pairs of menisci in a four‐menisci configuration on the nature of the DEP well formed at the center. A design parameter, Θ, capturing the dimensions of the DEP energy well, is defined and simulations exploring the effects of different geometric features on Θ are presented.
The locally conservative Galerkin (LCG) method for solving the incompressible Navier–Stokes equations
Authors: Thomas C. G. , Nithiarasu P. , Bevan R. L. T. 
Published: December 2007

AbstractIn this paper, the locally conservative Galerkin (LCG) method (Numer. Heat Transfer B Fundam. 2004; 46:357–370; Int. J. Numer. Methods Eng. 2007) has been extended to solve the incompressible Navier–Stokes equations. A new correction term is also incorporated to make the formulation to give identical results to that of the continuous Galerkin (CG) method. In addition to ensuring element‐by‐element conservation, the method also allows solution of the governing equations over individual elements, independent of the neighbouring elements. This is achieved within the CG framework by breaking the domain into elemental sub‐domains. Although this allows discontinuous trial function field, we have carried out the formulation using the continuous trial function space as the basis. Thus, the changes in the existing CFD codes are kept to a minimum. The edge fluxes, establishing the continuity between neighbouring elements, are calculated via a post‐processing step during the time‐stepping operation. Therefore, the employed formulation needs to be carried out using either a time‐stepping or an equivalent iterative scheme that allows post‐processing of fluxes. The time‐stepping algorithm employed in this paper is based on the characteristic‐based split (CBS) scheme. Both steady‐ and unsteady‐state examples presented show that the element‐by‐element formulation employed is accurate and robust. Copyright © 2007 John Wiley & Sons, Ltd.
High‐order 𝒞1 finite‐element interpolating schemes—Part I: Semi‐Lagrangian linear advection
Authors: Djoumna G. , Pierre R. , Le Roux D. Y. 
Published: December 2007

AbstractThis paper is devoted to the development of accurate high‐order interpolating schemes for semi‐Lagrangian advection. The characteristic‐Galerkin formulation is obtained by using a semi‐Lagrangian temporal discretization of the total derivative. The semi‐Lagrangian method requires high‐order interpolators for accuracy. A class of 𝒞1 finite‐element interpolating schemes is developed and two semi‐Lagrangian methods are considered by tracking the feet of the characteristic lines either from the interpolation or from the integration nodes. Numerical stability and analytical results quantifying the amount of artificial viscosity induced by the two methods are presented in the case of the one‐dimensional linear advection equation, based on the modified equation approach. Results of test problems to simulate the linear advection of a cosine hill illustrate the performance of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd.
A comparison of solvers for quadratic eigenvalue problems from combustion
Authors: Sensiau C. , Nicoud F. , van Gijzen M. , van Leeuwen J. W. 
Published: December 2007

AbstractTwo iterative subspace methods (Arnoldi and Jacobi–Davidson) are compared for solving typical quadratic eigenvalue problems arising when studying combustion instabilities. An academic, representative test case is presented with associated analytical solution. The efficiency of the iterative methods is studied in terms of running time when 1–10 eigenpairs are sought for, the computational domain being discretized with 500–32 000‐node finite element meshes. The sensitivity of the methods to the dimension of the search subspace is also investigated. Copyright © 2007 John Wiley & Sons, Ltd.
A fully implicit, mass‐conserving, semi‐Lagrangian scheme for the f‐plane shallow‐water equations
Authors: Thuburn J. 
Published: December 2007

AbstractA fully implicit, mass‐conserving, semi‐Lagrangian discretization of the shallow‐water equations on a doubly periodic f‐plane is proposed. The scheme requires the solution of a nonlinear and nonlocal system of equations at each time step. When a Newton method is used to solve this system of equations, a partial elimination of the unknowns can be carried out to leave a near standard elliptic problem at each Newton iteration, for which efficient solution methods are well known. Moreover, the nonlinearity is, in fact, rather weak so that a small number of Newton iterations (1–3) should be sufficient for practical application.Setting up the Newton method and solving the resulting elliptic problem can be made cheaper by making certain approximations to the terms in the Jacobian matrix; the price to pay is a slowing of the Newton convergence rate. Numerical experiments are carried out to quantify the effects on convergence rate of such approximations to help decide the optimum trade‐off between cost per Newton iteration and iteration count. Copyright © 2007 John Wiley & Sons, Ltd.
Practical considerations in the use of polarized light microscopy in the analysis of the collagen network in articular cartilage
Authors: Rieppo Jarno , Hallikainen Jarmo , Jurvelin Jukka S. , Kiviranta Ilkka , Helminen Heikki J. , Hyttinen Mika M. 
Published: December 2007

AbstractPolarized light microscopy is a traditional method for visualizing the collagen network architecture of articular cartilage. Articular cartilage repair and tissue engineering studies have raised new demands for techniques capable of quantitative characterization of the scar and repair tissues, including properties of the collagen network. Modern polarized light microscopy can be used to measure collagen fibril orientation, parallelism, and birefringence. New commercial instruments are computer controlled and the measurements are easy to perform. However, often the interpretation of results causes difficulties, even errors, because the theoretical aspects of the technique are demanding. The aim of this study was to describe the instrumentation and properties of a modern polarized light microscope, to point out some sources of error in the interpretation of the results, and to recall the theoretical background of the polarized light microscopy. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Characterization of Antarctic psychrotrophic bacteria with antibacterial activities against terrestrial microorganisms
Authors: Lo Giudice Angelina , Bruni Vivia , Michaud Luigi 
Published: December 2007

AbstractFive‐hundreds and eighty bacterial strains, isolated from various Antarctic marine sources and locations, were screened for antimicrobial activity against terrestrial microorganisms. Twenty‐two Antarctic isolates (3.8%), mainly retrieved from the water column at Terra Nova Bay (Ross Sea), expressed antagonistic activity against one to three indicator organisms. Escherichia coli and Proteus mirabilis resulted as the more susceptible, followed by Micrococcus luteus and Bacillus subtilis. None of the isolates inhibited the growth of Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella enterica and the eukaryotic fungus Candida albicans.Active Antarctic isolates, identified by 16S rDNA sequencing and phenotypically characterized by classical methods, were phylogenetically affiliated to the Actinobacteria (16 strains) and the γ‐Proteobacteria (6 strains). Inhibition patterns, as well as phenotypic characteristics, highly vary for different isolates, even though they were affiliated to the same genus or closely related to the identical microorganism retrieved from the database, suggesting that these features were more likely strain‐rather than species‐specific.Results obtained from the present study confirm previous observations and highlight the potentiality of Antarctic marine bacteria as novel source of antibacterial substances. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PAM‐Microfabricated Polyurethane Scaffolds: in vivo and in vitro Preliminary Studies
Authors: Vozzi Giovanni , Rechichi Alfonsina , Dini Francesca , Salvadori Claudia , Vozzi Federico , Burchielli Silvia , Carlucci Fabio , Arispici Mario , Ciardelli Gianluca , Giusti Paolo , Ahluwalia Arti 
Published: December 2007

AbstractPolymeric scaffolds were realised with linear degradable PU in the form of square, hexagonal and octagonal grids. They were characterised in terms of their mechanical properties. Analysis shows that the mechanical properties of the scaffolds depend on their geometries which are easily modulated using PAM. In vitro biological assays showed that PU promotes the adhesion and proliferation of fibroblast cells and that cell activities are better on PU scaffolds than on PU films. In vivo implantation of PU and PLGA scaffolds and PU films demonstrated that the scaffolds are completely resorbed after three months with a slight inflammatory response, while the PU film was still present after six months with an intense granulomatous reaction.magnified image
Optimizing periodic inspections in chemical plants by corrosion monitoring
Authors: Winkelmans M. , Müller U. , Bassler H.‐J. 
Published: December 2007

AbstractAn efficient industrial corrosion monitoring system would give information about the corrosion activity and corrosion damage of critical components within a chemical plant in real time. A research project to develop an industrial tool for the simultaneous monitoring of general and localized corrosion was initiated. General and localized corrosion can be monitored by combining several non‐destructive techniques.An industrial probe for corrosion monitoring is an excellent tool for an intelligent material selection, to identify critical process conditions or to optimize the use of corrosion inhibitors.The highest added value of an industrial tool for corrosion monitoring is its capacity to optimize periodic inspections.
Use of the wavelet method for analyzing electrochemical noise data
Authors: Duran O. , Vera E. , Ortiz C. A. , Heyn A. 
Published: December 2007

AbstractThis research paper shows the application of the mathematical tool “wavelet's” to be used in the interpretation and analysis of electrochemical noise signals. The Fast Fourier Transformation (FFT) is one of the most commonly used techniques for analyzing electrochemical noise. But the application of this methodology to the analysis of stochastic signals does not allow their interpretation in a suitable way. The wavelet's methodology carries out the analysis by means of the construction of finite base functions. In several studies, it has been found out that the function that is closest to the electrochemical oscillations is the one called “coiflets,” which presents a similar geometry to what it is observed when an ionic–electronic interchange occurs during an electrochemical interphase. The analysis that appears here was implemented using the toolbox “LabView™.”
Aliphatic Polyesters of Butyne‐1,4‐Diol
Authors: Kricheldorf Hans R. , Gao Quinwei , Buzin Pavel , Schwarz Gert 
Published: December 2007

AbstractPolyesters of butyne‐1,4‐diol (ByD) and aliphatic dicarboxylic acids (ADAs) were prepared in three different ways. Method I is based on the transesterification of ByD with the dimethyl esters of ADAs in bulk. Although catalyst and temperature were varied, only oligomers were obtained, because even at 220 °C the conversions were far from complete. Higher molar masses resulted from method II, the acid‐catalyzed polycondensation of ByD with sebacic acid, but this method yielded a high fraction of ether groups. The best results were obtained from method III, which consisted of pyridine‐catalyzed polycondensations of ByD and various ADA dichlorides at 0–20 °C. SEC measurements yielded corrected number average molecular weights ($\overline M _{\rm n}$) up to 20 000 Da. The success of this method depended largely on the excess of the ADA dichloride in the feed ratio. MALDI‐TOF mass spectrometry evidenced that under optimized reaction conditions the chain‐growth was mainly limited by cyclization. With the exception of the polysuccinate, all polyesters were rapidly crystallized materials with melting temperatures in the range of 50–90 °C.magnified image
Freezing of gait and executive functions in patients with Parkinson's disease
Authors: Amboni Marianna , Cozzolino Autilia , Longo Katia , Picillo Marina , Barone Paolo 
Published: December 2007

AbstractFreezing of gait (FOG) is a frequent, disabling symptom of Parkinson's disease (PD). FOG usually lasts a few seconds. It refers to brief paroxysmal events during which a subject is unable to start or continue locomotion. Despite its frequency, FOG pathophysiology is unclear. Because a frontal lobe dysfunction or a disconnection between the frontal lobe and basal ganglia has been implicated in FOG, we explored frontal functions in PD patients using neuropsychological tests. Thirteen early‐stage PD patients [Hoehn & Yahr score (H&Y) ≤ 2.5] with freezing during “on ” state (FOG+), and 15 age‐, H&Y score‐, and disease‐duration‐matched PD patients without freezing (FOG−) were investigated. No patient was demented or depressed. Assessment included the Unified Parkinson's Disease Rating Scale (UPDRS), FOG questionnaire, Mini Mental State Examination (MMSE), frontal assessment battery (FAB), phonemic verbal fluency, Stroop test (parts II and III), and ten‐point clock test (TPCT). UPDRS and MMSE scores did not differ between the two groups. FAB, verbal fluency, and TPCT scores were significantly lower in FOG+ patients than in FOG− patients (FAB: P = 0.008; phonemic verbal fluency: P = 0.011; TPCT: P = 0.024). FOG correlated with lower scores at frontal tests in patients with early‐stage PD. © 2007 Movement Disorder Society
The development of duodenal microadenomas in FAP patients: the human correlate of the Min mouse
Authors: Preston SL , Leedham SJ , Oukrif D , Deheregoda M , Goodlad RA , Poulsom R , Alison MR , Wright NA , Novelli M 
Published: December 2007

AbstractThe morphological changes associated with the adenoma‐carcinoma sequence are well documented in the colorectum. Small intestinal carcinogenesis is thought to progress through a similar adenoma‐to‐carcinoma pathway, but there is a relative dearth of studies examining the associated morphological changes. The best‐known mouse model of intestinal neoplasia, the multiple intestinal neoplasia (Min) mouse, has been criticized as a genetic model of intestinal neoplasia, as the majority of its tumours occur in the small intestine. We examined pancreatico‐duodenal resection specimens from seven familial adenomatous polyposis (FAP) patients. Serial sections of these were stained with haematoxylin and eosin for β‐catenin and its downstream target CD44, for BMPR1a, lysozyme, carbonic anhydrase II, and with MIB‐1. Individual dysplastic crypts were isolated and mutations in the FAP (APC) gene compared between the top and bottom of the crypt. We found that: (a) duodenal microadenomas are extremely common in FAP patients; (b) these grow in the core of duodenal villi, forming lesions similar to those described in the Min mouse; (c) many lesions arise as monocryptal adenomas and grow by a process of crypt fission and branching; (d) migrating adenomatous cells lose their dysplastic phenotype as they migrate up the crypt villous axis; and (e) Paneth cells lose positional information. In conclusion: (a) the morphological similarity of adenomas in the Min mouse and human suggest the Min mouse is a good model of FAP; (b) duodenal adenomas in FAP originate in monocryptal adenomas and follow the ‘bottom‐up’ rather than the ‘top‐down’ model of morphogenesis; (c) early microadenomas show evidence of cellular differentiation; (d) defects in the positioning of Paneth cells suggests disruption of the EphB2:EphB3 receptor system. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Suitability of two laboratory testing methods to evaluate the side effects of pesticides on Typhlodromus pyri Scheuten (Acari: Phytoseiidae)
Authors: Bonafos Romain , Auger Philippe , Guichou Sabine , Kreiter Serge 
Published: December 2007

AbstractBACKGROUND: Laboratory results of the French ANPP/CEB guideline No. 167 and IOBC/WPRS Ring Testing Group methods for testing the side effects of pesticides on the predatory mite Typhlodromus pyri Scheuten were compared with respect to their suitability to evaluate the toxicity of three pesticides.RESULTS: Results obtained with the ANPP/CEB guideline allow the demonstration of significant differences between two slightly toxic products, a dichlofluanid 500 g kg−1 kWP (Euparen® 50WP) and a quinoxyfen 250 g L−1 SCC (Legend®), and a highly toxic cymoxanil 60/mancozeb 200/folpet 275 g kg−1 WP [Remiltine F Pepite® (RFP)], on the basis of bioassays conducted in the laboratory. In contrast, results obtained with the IOBC/WPRS method classified all three as harmful.CONCLUSION: The evaluation of the toxicity of RFP revealed that the concentration, the quantity of the wet deposit and the food source used in the IOBC/WPRS method maximise the toxicity, in comparison with those used in the ANPP/CEB protocol. Valid criteria in controls were all respected in the ANPP/CEB tests but not in the IOBC/WPRS samples. This result revealed difficulties related to the use of the IOBC/WPRS method in laboratories. Copyright © 2007 Society of Chemical Industry
The dependence of luminescence lifetimes on additive irradiation in natural sedimentary quartz: sands from Santa Elina, Brazil
Authors: Chithambo M. L. , Ogundare F. O. , Feathers J. , Hong D. G. 
Published: December 2007

AbstractTime‐resolved luminescence and its component lifetimes have been measured from natural quartz in order to interpret the associated dynamics of luminescence emission. The influence of beta irradiation, and measurement temperature on the lifetimes have been investigated and parameters of the kinetics involved calculated. The results are explained by considering the extent of non‐radiative processes and the role of charge transfer between several types of luminescence centres. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)