bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the Start Transient in a Hall Thruster
Authors: Liu H. , Yu D. R. , Yan G. J. , Liu J. Y. 
Published: December 2008

AbstractA two dimensional axisymmetric fully kinetic Particle‐in‐Cell/Monte Carlo Collision (PIC‐MCC) model is used to describe the ignition process in a Hall thruster. A current peak and latter the periodic oscillation of current and electric potential are found. The corresponding evolutions of plasma density, electric potential and atom density during the ignition process are introduced in the paper. In addition, influences of mass flow rate and discharge potential on current peak are modeled and analyzed. The simulated results are consistent with former experimental results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Oscillating Sheath on Near‐Wall Electron Current Profile in Hall Thrusters
Authors: Yu D. R. , Liu H. , Ning Z. X. , Yan G. J. 
Published: December 2008

AbstractThe radial profile of the axial electron current in Hall thrusters was measured; however, the significant decay of the current density peak in the near‐wall region can't be explained effectively by the steady sheath theory. As the sheath exhibits an oscillating character when the thruster is in operation, its effect on the near‐wall current profile has been studied in this paper. To obtain a comprehensive knowledge, we have considered a wide sheath oscillation frequency span which includes two asymptotic frequency cases at high and low ends. Based on the case studied, either an analytical treatment or a numerical simulation is applied. The results show that the current density peak has a fastest damping speed away from the wall at the asymptotic low frequency. With the increase of the frequency, both the decay and the spatial “wavelength” of the current profile decrease. The decay finally disappears at the asymptotic high frequency with a constant spatial “wavelength”. Moreover, the sheath oscillation amplitude can enhance the decay and enlarge the spatial “wavelength”. Taking into account of the realistic situation in Hall thrusters, the significant impact of the oscillating sheath on the near‐wall electron current profiles can be anticipant. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamics and Phase Transitions in Dense Hydrogen – the Role of Bound State Energy Shifts
Authors: Ebeling W. , Redmer R. , Reinholz H. , Röpke G. 
Published: December 2008

AbstractIn recent papers we have investigated the effects of Pauli blocking on the energy shifts in dense hydrogen. As Pauli blocking we denote effects on the shifts which result from the antisymmetry of the electronic wave functions. Here we study of the thermodynamic properties of dense hydrogen including the influence of energy shifts. Of special interest is the region where a transition from insulating behavior to metal‐like conductivity has been shown experimentally. In this region, Pauli blocking effects have a deciding influence on this transition. Assuming that the system is a gas‐like mixture of chemical species, the ionization equilibrium is treated by an advanced chemical approach. We calculate the Pauli and Fock shifts by perturbation theory and variational methods and construct useful interpolation formulae. Results for the ionization equilibrium are presented for temperatures between 4 000 K < T < 20 000 K and densities in the range n = (2–6) × 1023cm–3 where the transition from a neutral hydrogen gas to a highly ionized plasma occurs. The results for the equation of state and the relative pressure indicate that the transition to a highly conducting state is softer than derived in earlier work. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prediction of flocculation ability of brewing yeast inoculates by flow cytometry, proteome analysis, and mRNA profiling
Authors: Heine Franziska , Stahl Frank , Sträuber Heike , Wiacek Claudia , Benndorf Dirk , Repenning Cornelia , Schmidt Frank , Scheper Thomas , von Bergen Martin , Harms Hauke , Müller Susann 
Published: December 2008

AbstractThe ability of brewing yeast to flocculate is an important feature for brewing of qualitatively good beer. Flocculation involves two main cell wall structures, which are the flocculation proteins (flocculins) and mannans, to which these flocculins bind. Unfortunately, in practice, the flocculation ability may get lost after several repitches. Flow cytometry was employed to analyze glucose and mannose structures of the cell surface by application of fluorescent lectins. Validation of the expression of the flocculin genes Lg‐FLO1, FLO1, FLO5, and FLO9 was carried out using microarray techniques. SDS‐PAGE, western blot, and ESI‐MS/MS analyses served to isolate and determine yeast cell flocculins. Mannose and glucose labeling with fluorescent lectins allowed differentiating powdery and flocculent yeast cells under laboratory conditions. Using microarray techniques and proteomics, the four flocculation genes Lg‐FLO1, FLO1, FLO5, FLO9, and the protein Lg‐Flo1p were identified as factors of major importance for flocculation. The expression of the genes was several times higher in flocculent yeast cells than in powdery ones. Flow cytometry is a fast and simple method to quantify the proportions of powdery and flocculent yeast cells in suspensions under defined cultivation conditions. However, differentiation under industrial conditions will require mRNA and protein expression profiling. © 2008 International Society for Advancement of Cytometry
Supercontinuum white light lasers for flow cytometry
Authors: Telford William G. , Subach Fedor V. , Verkhusha Vladislav V. 
Published: December 2008

AbstractExcitation of fluorescent probes for flow cytometry has traditionally been limited to a few discrete laser lines, an inherent limitation in our ability to excite the vast array of fluorescent probes available for cellular analysis. In this report, we have used a supercontinuum (SC) white light laser as an excitation source for flow cytometry. By selectively filtering the wavelength of interest, almost any laser wavelength in the visible spectrum can be separated and used for flow cytometric analysis. The white light lasers used in this study were integrated into a commercial flow cytometry platform, and a series of high‐transmission bandpass filters used to select wavelength ranges from the blue (∼480 nm) to the long red (>700 nm). Cells labeled with a variety of fluorescent probes or expressing fluorescent proteins were then analyzed, in comparison with traditional lasers emitting at wavelengths similar to the filtered SC source. Based on a standard sensitivity metric, the white light laser bandwidths produced similar excitation levels to traditional lasers for a wide variety of fluorescent probes and expressible proteins. Sensitivity assessment using fluorescent bead arrays confirmed that the SC laser and traditional sources resulted in similar levels of detection sensitivity. Supercontinuum white light laser sources therefore have the potential to remove a significant barrier in flow cytometric analysis, namely the limitation of excitation wavelengths. Almost any visible wavelength range can be made available for excitation, allowing access to virtually any fluorescent probe, and permitting “fine‐tuning” of excitation wavelength to particular probes. © 2008 International Society for Advancement of Cytometry
Close association of CD8+/CD38bright with HIV‐1 replication and complex relationship with CD4+ T‐cell count
Authors: Tuaillon Edouard , Al Tabaa Yassine , Baillat Vincent , Segondy Michel , Picot Marie‐Christine , Reynes Jacques , Vendrell Jean‐Pierre 
Published: December 2008

AbstractBackground:Measuring lymphocyte activation provides information in addition to CD4+ T‐cell count for immune monitoring of HIV‐1 infected patients. CD38 is a well‐established activation marker that is generally analyzed on the whole population of CD8+ T‐cells. Focusing specifically on CD38 high expression (CD8+/CD38bright) may be an interesting surrogate gating strategy because CD38bright characterizes principally activated memory cells.Methods:CD8+/CD38bright was investigated in 1,353 HIV‐1 infected patients over a one‐year period to establish relevant cutoff values and clarify the relationships of this marker with HIV‐1 RNA viral load (VL) and CD4+ T‐cell count.Results:The CD8+/CD38bright (>8,500 CD38 binding site per cells) is well correlated with HIV‐1 VL (r = 0.87, P < 0.001) in this longitudinal follow‐up of nonimmunodepressed patients that initiated antiviral therapy (ART). In aviremic patients on ART, the marker was highly predictive of VL rebound (sensitivity 93%, specificity 64% for a VL level of detection >200 copies/ml). While the CD8+/CD38bright moderately correlated with CD4+ T‐cell count independently of the VL (r = −0.37, P < 0.001), it increased dramatically in aviremic patient groups that exhibited profound CD4+ T‐cell depletion (median 39% for CD4+ T‐cell counts <50/mm3). This result indicates that other additional immunological and/or viral factors than readily detectable HIV‐1 replication appears to be involved in T‐cell activation of immunodepressed individuals.Conclusions:CD8+/CD38bright is an effective marker for monitoring T‐cell activation, which is a central factor of HIV‐1 pathogenesis. This gating strategy requires only a single additional staining in conventional four color CD4 protocols. © 2008 Clinical Cytometry Society
Cognitive neuroscience of Attention Deficit Hyperactivity Disorder: Current status and working hypotheses
Authors: Vaidya Chandan J. , Stollstorff Melanie 
Published: December 2008

AbstractCognitive neuroscience studies of Attention Deficit Hyperactivity Disorder (ADHD) suggest multiple loci of pathology with respect to both cognitive domains and neural circuitry. Cognitive deficits extend beyond executive functioning to include spatial, temporal, and lower‐level “nonexecutive” functions. Atypical functional anatomy extends beyond frontostriatal circuits to include posterior cortices, limbic regions, and the cerebellum. Pathophysiology includes dopaminergic as well as noradrenergic neurotransmitter systems. We review the major insights gained from functional brain imaging studies in ADHD and discuss working hypotheses regarding their neurochemical underpinnings. © 2008 Wiley‐Liss, Inc. Dev Disabil Res Rev 2008;14:261–267.
The neurobiological profile of girls with ADHD
Authors: Mahone E. Mark , Wodka Ericka L. 
Published: December 2008

AbstractSince boys are more commonly diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) than girls, the majority of theories and published research studies of ADHD have been based on samples comprised primarily (or exclusively) of boys. While psychosocial impairment in girls with ADHD is well established, the neuropsychological and neurobiological basis of these deficits is less consistently observed. There is growing evidence that boys' and girls' brains develop and mature at different rates, suggesting that the trajectory of early anomalous brain development in ADHD may also be sex‐specific. It remains unclear, however, whether earlier brain maturation observed in girls with ADHD is protective. In this review, we outline the current theory and research findings that seek to establish a unique neurobiological profile of girls with ADHD, highlighting sex differences in typical brain development and among children with ADHD. The review highlights findings from neurological, neurocognitive, and behavioral studies. Future research directions are suggested, including the need for longitudinal neuroimaging and neurobehavioral investigation beginning as early as the preschool years, and continuing through adolescence and adulthood, with consideration of identified sex differences in the development of ADHD. © 2008 Wiley‐Liss, Inc. Dev Disabil Res Rev 2008;14:276–284.
Aktuelle europäische Rechtsänderungen – ein kurzer Überblick
Authors: Abend Kerstin 
Published: December 2008

AbstractDer europäische Gesetzgeber hat in jüngster Zeit verschiedenste Rechtsänderungen auf den Weg gebracht, die sich unmittelbar auf den Baubereich auswirken. So ist ein “Binnenmarktpaket für Waren” mit zwei Verordnungen und einem Beschluss verabschiedet worden, überwiegend anwendbar ab 2010, teils ab Mai 2009. Gleichzeitig wird die Bauproduktenrichtlinie überarbeitet. Sie soll durch eine europäische Bauprodukteverordnung, voraussichtlich ab Juli 2011, ersetzt werden. Ein entsprechender Kommissionsvorschlag ist noch in der Diskussion. Nachfolgend werden ein kurzer Überblick über die neue Rechtslage, deren wichtigsten Auswirkungen im Baubereich sowie eine Zwischeninformation über die Arbeiten zum Vorschlag der Kommission für eine Bauprodukteverordnung gegeben sowie eine Stellungnahme des Bundesrates zum Kommissionsvorschlag abgedruckt.
(1,3,4‐Oxadiazole)copper(II) Compounds: Dimensionality, Magnetism and Nuclease Activity
Authors: Gómez‐Saiz Patricia , Gil‐García Rubén , Maestro Miguel A. , Arnaiz Francisco J. , Lezama Luis , Rojo Teófilo , Pizarro José Luis , Arriortúa María Isabel , González‐Álvarez Marta , Borrás Joaquín , Diez‐Gómez Virginia , García‐Tojal Javier 
Published: December 2008

AbstractThe work presented here describes the synthesis of new copper(II) complexes derived from 2‐amino‐5‐(pyridin‐2‐yl)‐1,3,4‐oxadiazole (L1) and 2‐methylamino‐5‐(pyridin‐2‐yl)‐1,3,4‐oxadiazole (L2) which also incorporate azido (N3–),thiocyanato (NCS–), cyanato (NCO–), dicyanamido [N(CN)2–, dca] and malonato (C3H2O42–, mal) coligands. Structures of the [Cu(L2)(mal)(H2O)]·2H2O (1), [{Cu(L2)(mal)}2] (2), [Cu(L2)2(NCS)2] (3), [Cu(L1)(NCS)2]n (4) and [{Cu(L2)}2(dca)2](ClO4)2·2H2O (5) compounds show the dependence of the dimensionality on parameters such as the type of oxadiazole and coligand utilised, solvents or reaction times. In this sense, 1 and 3 are mononuclear complexes, 2 contains centrosymmetric dinuclear entities, 4 is a 1D compound in which thiocyanato groups act as end‐to‐end bridges and 5 shows a 2D arrangement of dinuclear motifs linked through dicyanamido spacers. The copper(II) ions acquire distorted octahedral (3 and 4), square‐pyramidal (1 and 2) and trigonal bipyramidal (5) geometries. Stacking π–π interactions and hydrogen bonds stabilise the crystal frameworks. Water tetramers are present in 1. Spectroscopic (infrared, UV/Vis absorption and electron spin resonance) studies have also been developed for 1–5 and for the Cu(L2)(dca)2(H2O) (6), Cu(L2)(NCO)2 (7) and Cu(L2)2(N3)2(H2O)2 (8) complexes. The studies suggest the coordination of oxadiazole and coligands in all cases. Magnetic measurements show antiferromagnetic coupling for compound 5, ferromagnetic interactions for compound 2 and paramagnetic behaviour in compound 4. The susceptibility data were fitted by using the Bleaney–Bowers' equation for the copper(II) dimers derived from H = –2JS1S2. The resultant J/k values are +2.15 and –38.3 K for compounds 2 and 5, respectively. Magneto‐structural correlations are discussed and extended to more than 30 published dinuclear Cu(NN)2Cu′ diazole‐only bridged compounds. All these systems show J values close to or greater than those given by the expression J ≈ –90 + 3 Δβ (where Δβ is the difference between the Cu–N–N and Cu–N′–N′ angles). The artificial nuclease activity of 1, 2, 3 and 5 in the presence of mercaptopropionic acid or glutathione has also been analysed and compared with that exhibited by [Cu(L2)2(H2O)2](NO3)2 and CuSO4. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of (Alkylamino)nitroarenes by Oxidative Alkylamination of Nitroarenes
Authors: Gulevskaya Anna V. , Verbeeck Stefan , Burov Oleg N. , Meyers Caroline , Korbukova Inna N. , Herrebout Wouter , Maes Bert U. W. 
Published: December 2008

AbstractThe viability of the oxidative alkylamination process for the derivatization of electron‐deficient carboaromatics has been investigated. 1,3‐Dinitrobenzene, 1‐nitronaphthalene, and 1,5‐ and 1,8‐dinitronaphthalenes have shown to react with a wide range of alkylamines in the presence of an oxidant (KMnO4, AgMnO4, AgPy2MnO4) to give access to the corresponding N‐alkyl‐nitroarenamines in moderate to good yields. Nitroarenes are more reactive than azines towards alkylamines.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Rigid π‐Conjugated Mono‐, Bis‐, Tris‐, and Tetrakis(terpyridine)s: Influence of the Degree and Pattern of Substitution on the Photophysical Properties
Authors: Winter Andreas , Friebe Christian , Hager Martin D. , Schubert Ulrich S. 
Published: December 2008

AbstractA series of rigid π‐conjugated mono‐, bis‐, tris‐, and tetrakis(terpyridine)s 3–8 was synthesized in high yields by means of Horner–Wadsworth–Emmons (HWE) reactions between benzyl phosphonates 1 and an aldehyde‐functionalized terpyridine derivative 2. The photophysical properties of the materials in solution and in the solid state depend strongly both on the numbers of terpyridine moieties attached to the central phenyl cores and on the geometries of the compounds. The photophysical behavior of the ortho‐substituted compounds 5 and 8 indicated significant changes in the geometries, together with major extensions of the effective π‐conjugated systems upon excitation. Bright green emission with high quantum yields was observed for the tetrakis(terpyridine) derivative 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Electrochemical Chiral Sensors and Biosensors
Authors: Trojanowicz Marek , Kaniewska Marzena 
Published: December 2008

AbstractChiral molecular recognition depends on difference in stability constants of diastereomeric complexes with applied selectors, different migration of enantiomers based on the formation and dissociation of diastereomeric complexes, and on a different interaction rate of enantiomers with selector. Selected examples of electrochemical enantioselective sensors and biosensors based on different mechanisms of molecular recognition are reviewed. Chemical chiral sensors can be based on plasticized membranes incorporating a chiral ionophore, on differences of Gibbs free energy for interphase electron transfer, or on the use of molecularly imprinted polymers and electrodeposited conducting polymers doped with chiral ions. Reported chiral biosensors include enzymatic devices and immunosensors. Especially pronounced enantioselectivity of enzymatic biosensors can be employed practically, e.g., in food control, showing chiral discrimination better that two orders of magnitude. Developed, so far, chemical sensors show enantioselectivity usually not exceeding two orders magnitude and require further investigation for any practical analytical applications.
Enzyme‐Amplified Amperometric Detection of DNA Using Redox Mediating Films on Gold Microelectrodes
Authors: Hajdukiewicz Joanna , Boland Susan , Kavanagh Paul , Nowicka Anna , Stojek Zbigniew , Leech Dónal 
Published: December 2008

AbstractHere we describe an amperometric assay for enzyme‐labeled detection of DNA hybridization based on a redox polymer film, cross‐linked and co‐immobilized, with a 20‐mer oligonucleotide, to pre‐adsorbed cysteamine on gold microelectrode surfaces. Hybridization between the immobilized probe DNA and a biotin‐modified target DNA (designed from the ssrA gene of Listeria monocytogenes), followed by addition of an enzyme (glucose oxidase)‐avidin conjugate and glucose, results in bioelectrocatalytic oxidation of glucose mediated by the redox polymer, generating significant amplification. The use of gold microelectrodes (25 μm, 40 μm, 100 μm diameter), coupled to careful preparation of surfaces, electronic shielding and background subtraction, results in improved analytical performance, compared to that at macroelectrodes, yielding a limit of quantification of ca. 0.6 pM, corresponding to the presence of ca. 2.5 million copies in the 7 μL assay droplet.
Lactate Dehydrogenase Biosensor Based on an Hybrid Carbon Nanotube‐Conducting Polymer Modified Electrode
Authors: Agüí L. , Eguílaz M. , Peña‐Farfal C. , Yáñez‐Sedeño P. , Pingarrón J. M. 
Published: December 2008

AbstractA lactate biosensor constructed by immobilization of the enzyme lactate dehydrogenase (LDH) on a glassy carbon electrode modified with a hybrid material composed of the conducting polymer poly (3‐methylthiophene) (P3 MT), electrodeposited on the electrode surface, and multiwalled carbon nanotubes (MWCNTs), is reported. The excellent characteristics of the electrode modified with the hybrid material toward the electrochemical oxidation of NADH allowed the construction of a robust LDH electrochemical biosensor able to operate at a working potential as low as +300 mV without the need for redox mediator. Experimental variables affecting the performance of the biosensor: amount of LDH immobilized on the modified electrode surface, buffer composition and working pH value, MWCNTs loading in the hybrid material and NAD+ concentration were optimized. Under the optimized conditions, a linear calibration graph for lactate was obtained over the 1.0×10−6−5.0×10−4 M (r=0.9993) concentration range, with a detection limit of 5.6×10−7 M. The biosensor design showed good repeatability of the measurements, good reproducibility in the inter‐biosensor assays and a good selectivity against other organic acids, especially when the biosensor is coated with a Nafion film.
Measurement of Dissolved Oxygen in Biological Fluids by Using a Modified Carbon Paste Electrode
Authors: Jalali Fahimeh , Ashrafi Amir M. , Nematollahi Davood 
Published: December 2008

AbstractA modified carbon paste electrode was constructed for the determination of dissolved oxygen using diamino‐o‐benzoquinone (DABQ) as the modifier. The electrochemical behavior of the electrode in citrate buffer (pH 2.0) was studied. In the presence of dissolved oxygen (DO) both cathodic and anodic peak currents decreased, indicating a chemical reaction between modifier and O2. The decrease in peak current was linearly proportional to the amount of dissolved oxygen in the concentration range of 252–1260 μM of DO. The electrode was utilized in the determination of DO in urine samples. The relative error and RSD of the method were 1.6% and 4.1%, respectively. The electrode was applied more than two months for the determination of DO without any significant divergence in its voltammetric response.
New Protocol for Determination of Rifampicine by Adsorptive Stripping Voltammetry
Authors: Tyszczuk Katarzyna , Korolczuk Mieczyslaw 
Published: December 2008

AbstractFor determinations of organic compounds by adsorptive stripping voltammetry till now the same material of the electrode has been used for the accumulation and stripping steps. This paper describes a new protocol for extending the range of organic compounds, which can be determined by adsorptive stripping voltammetry. In the proposed procedure the accumulation step was performed on the electrode modified by a lead film, which assures adsorption of the studied species on the modified electrode and then the stripping step of the accumulated substance was performed on the support of the lead film electrode. As an example rifampicine was accumulated by adsorption at the lead film electrode while in the stripping step lead film and then the accumulated rifampicine were oxidized at a glassy carbon electrode. Using an acetate buffer as a supporting electrolyte a calibration graph for rifampicine in the range from 2.5×10−10 to 1×10−8 mol L−1 was obtained. The detection limit for rifampicine following 60 s accumulation time was equal to 9×10−11 mol L−1. The obtained detection limit was comparable or lower than reported previously for other stripping voltammetric procedures. The proposed procedure was applied to rifampicine determination in pharmaceutical preparation.