bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long Time Behaviour of Marginally Stable Magnetomodulational Perturbation
Authors: Majumdar D. , Bhakta J. C. 
Published: July 2007

AbstractThe long time behaviour of magnetomodulational perturbation has been investigated by using multiple time scale perturbation method. If the perturbation field is purely potential, it is found that unlike ordinary modulational unstability the magnetomolulational instability persists in the nonlinear stage of evolution. The exact analytical solution obtained for the marginally stable mode of the linear theory exhibits explosively unstable behaviour in the slow time scale. When both potential and solenoidal components of perturbation are present the transverse exerts a stabilising influence. Different kinds of long time behaviour may occur as medicated by the results of the numerical integration of the coupled nonlinear evolution equations for the Langmuir and transverse fields.
Electron Density and Temperature Rise Time of a Weakly Ionized Oxygen Plasma Subject to an Alternating Electric Field
Authors: Baumgärtel K. , Sauer K. , Wilhelm J. , Winkler R. 
Published: July 2007

AbstractMacroscopic balance equations for particle number, momentum and energy of the electrons are derived from the Boltzmann equation which describe the time evolution of a weakly ionized oxygen plasma exposed to an alternating homogeneous electric field. The equations are applied to estimate the rise time of electron temperature and density when a rf pulse is emitted from a satellite into the ionospheric plasma.
Computermodelling of Fluorescent Lamp Plasmas
Authors: Sonnenburg R. , Gündel H. 
Published: July 2007

Abstract
A computer model is designed in which the lamp voltage is obtained by solving the equations of the operating circuit.
The lamp resistance is determined by using hydrodynamic equations for the lamp plasma with following conditions:

— three level model of Hg vapour ground, one lumped excited and the ionization level
— direct and stepwise ionization are included as well as deexcitation and radiative decay
— the plasma is controlled by ambipolar diffusion
— no excitation and ionization of the buffer gas is assumed
— both the buffer gas and neutral Hg atoms are considered to be equal distributed over the cross‐section of the discharge tube.

The model allows to calculate the main time dependent lamp parameters and their time averaged values.
We found a good qualitative and quantitative (about 1 to 5%) agreement compared with standard fluorescent lamps.
The model shows the tendency of lamp voltage increasing to smaller tube diameters.
The model gives qualitatively the right dependence of lamp efficacy on the buffer gas pressure.
The behaviour of the angle of lag and the power factor in dependence on the tube diameter obtained by the model shows also the right tendency.
Further calculations and experimental verifications are needed to reach several improvements of the model.
Study of the Stimulated Brillouin Scattering in a Dissipative Two‐Ion Species Plasma
Authors: Guha S. , Dwivedi C. B. 
Published: July 2007

AbstractAnalytical study of the stimulated Brillouin scattering in a two‐ion species plasma has been done using the hydrodynamical model. When strong nonlinear effect becomes significant i.e., when the quiver velocity of the electron becomes of the order of or greater than its thermal velocity, the damping becomes intensity dependent which modifies the results over the weak nonlinearity. In this regime the plasma behaves as a collisionless medium. The inclusion of the second species of the ions modifies the instability and decreases the growth rate. Its application in fusion plasma has been discussed.
Data Smoothing Effects on the Abel Inversion Method in Plasma Spectroscopy
Authors: Sato M. 
Published: July 2007

AbstractAn investigation is given for the effects of smoothing on the Abel inversion method for obtaining radial intensity profiles from chordal intensity profiles. Before the radial intensities are calculated by means of the familiar inversion methods, such as by Nestor‐Olsen, Bockasten, Frie, etc., the chordal intensities with random scatterings are smoothed by easily available methods, the least‐square fitting with Taylor expansion correction and the B‐spline fitting. Through numerical simulation tests, it is shown that this procedure of smoothing is very useful for an accurate Abel inversion without relying upon more complicated inversion methods having clever smoothing processes, e.g., by Piessens, Fleurier and Chapelle, Glasser et al., etc.
Investigations on the Electron Component in an Argon‐Hexamethyldisiloxane (HMDS) Low Pressure Glow Discharge by Probe Diagnostics
Authors: Maass M. , Schmidt M. 
Published: July 2007

AbstractProbe measurements were carried out in the positive column of an argon glow discharge in a flow system with different admixtures of hexamethyldisiloxane (HMDS). From this the mean electron energy ne, number density ne and gradient E were determined. Some results concerning the predominant ionization mechanism and the ion distribution in the gas phase could be obtained. By means of probes it is also possible to get some information about the deposition mechanism in polymerizing plasmas.
A Multicomponent Theory of the Cathodic Plasma Jet in Vacuum Arcs
Authors: Wieckert C. 
Published: July 2007

AbstractIt was demonstrated in many experiments, that the expansion of the dense plasma of a vacuum arc spot goes along with an acceleration of multiply charged ions in the direction of the anode. The resulting plasma jet is analysed in a stationary and quasi‐onedimensional model, that accounts for virtually all existing explanations. The corresponding system of multifluid equations includes singular points. The model is evaluated for two versions, that are suited to describe the cathodic jet and for which the singular points can be treated. The agreement with the experimentel results is satisfactory. It turns out, that the acceleration of the ions is mainly due to the electron‐ion friction. The results indicate, that the study of the plasma jet is a suitable tool to get a more detailed knowledge of the cathode spot.
Recombination of a Xenon Plasma Jet
Authors: Anders A. 
Published: July 2007

AbstractAs pointed out in a previous paper, stable spherical plasma configurations can be produced by pulsed injection of a plasma into an ambient gas. It is shown here that the observed long plasma lifetime of several milliseconds is in agreement with collisional‐radiative recombination theories. We used the modified diffusion approximation by Biberman et al. involving thermal non‐equilibrium, recombination heating of electrons, heat conduction, radiation and other details. Under the assumption of a pure xenon plasma, the calculated plasma lifetime is even longer than the observed one. This discrepancy can be explained by the presence of molecules and turbulent mixing with the outer gas, which are not considered in the recombination calculation.
Energy Balance of Low‐Voltage Spark Discharges
Authors: Apostol I. , Mihailescu I. N. , Buteikis R. , Nashlenas E. , Serapinas P. 
Published: July 2007

AbstractIn this work we are presenting an experimental and theoretical analysis of the energy balance of low‐voltage spark discharges. It is pointed out that the greatest part of the energy from the central hot plasma region is lost in the form of radiation, but the radiation from electrode particles (here aluminium) can be important, too.
Spark Discharge Action on a Cathode Surface in Air Atmosphere
Authors: Apostol I. , Mihailescu I. N. , Popa A. L. , Buteikis R. , Oberauskas J. , Serapinas P. 
Published: July 2007

AbstractNew results obtained by electron microscopy investigations of cathode spot parameters are qualitatively and quantitatively analysed to the view of further understanding of the cathode processes in spark discharges.
CD5+ B cells with the features of subepithelial B cells found in human tonsils
Authors: Dono Mariella , Burgio Vito Lelio , Colombo Monica , Sciacchitano Salvatore , Reverberi Daniele , Tarantino Vincenzo , Cutrona Giovanna , Chiorazzi Nicholas , Ferrarini Manlio 
Published: July 2007

AbstractThis study describes a CD5+ B cell that differs from the majority of the CD5+ B cells from human tonsils. This cell, isolated from in vivo activated B cells, expressed activation markers and featured a CD23–, IgMhigh, IgDlow surface phenotype, responded to T cell‐independent type‐2 antigens in vitro, and was detected in the subepithelial (SE) areas, the tonsil equivalent of the splenic marginal zone (MZ). Most of the cells utilized unmutated Ig VH genes, although cells with mutated genes also were found, a finding confirmed by single‐cell studies. Mutated sequences were more frequent in suspensions enriched for CD27+ cells. Repeated VDJ gene sequences were observed in different molecular clones from the same cell suspension, suggesting in situ expansion. These CD5+ B cells seem to share features with previously characterized tonsil CD5– SE B cells and differ from the majority of tonsil CD5+ B cells, which have the surface phenotype of follicular mantle B cells, lack activation markers, do not respond to T cell‐independent antigens, and utilize unmutated VH genes. These data are discussed considering the present views on the origin of B cell subset populations and the relationships between MZ and B1 cells.
Mediastinal lymph node CD8α− DC initiate antigen presentation following intranasal coadministration of α‐GalCer
Authors: Ko Sung‐Youl , Lee Kyoo‐A , Youn Hyun‐Jun , Kim Yeon‐Jeong , Ko Hyun‐Jeong , Heo Tae‐Hwe , Kweon Mi‐Na , Kang Chang‐Yuil 
Published: July 2007

AbstractOur previous study revealed that α‐galactosylceramide (α‐GalCer) is a potent nasal vaccine adjuvant inducing both potent humoral and cellular immune responses and affording complete protection against viral infections and tumors. However, the antigen‐presenting cells (APC) that are activated by NKT cells and thereby initiate the immune responses following intranasal coadministration of protein antigen and α‐GalCer are poorly understood. We assessed here where antigen presentation occurs and which APC subset mediates the early stages of immune responses when protein antigen and α‐GalCer are intranasally administered. We show that dendritic cells (DC), but not B cells, initiated the mucosal immune responses at mediastinal lymph nodes. Of the DC subsets, the CD8α−B220−CD11c+ DC subset played the most prominent role in the direct and cross‐presentation of protein antigen to naive T cells and in triggering the naive T cells to differentiate into effector T cells. This might be mainly caused by a relatively larger population of CD1dhigh cells of CD8α−B220−CD11c+ DC subset than those of other DC subsets. These results indicate that CD8α−B220−CD11c+ DC is the principal subset becoming immunogenic after interaction with NKT cells and abrogating tolerance to intranasally administered protein antigen when α‐GalCer is coadministered as a nasal vaccine adjuvant.
Novel Ruthenium(II) N‐Heterocyclic Carbene Complexes as Catalyst Precursors for the Ring‐Opening Metathesis Polymerization (ROMP) of Enantiomerically Pure Monomers: X‐ray Structures, Reactivity, and Quantum Chemical Considerations
Authors: Buchmeiser Michael R. , Wang Dongren , Zhang Yan , Naumov Sergej , Wurst Klaus 
Published: July 2007

AbstractFour chiral, enantiomerically pure monomers, exo,exo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine ethyl ester (exo‐1),endo,endo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valineethyl ester (endo‐1), exo,exo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine‐tert‐butylamide (exo‐2), and endo,endo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine‐tert‐butylamide (endo‐2), were subjected to ring‐opening metathesis polymerization (ROMP) with Ru(CF3CO2)2(IMesH2)(p‐cymene) (3), Ru(CF3CO2)2(IMes)(p‐cymene) (4), RuCl2(IMes)(p‐cymene) (5), Ru(PCy3)(CF3CO2)2(p‐cymene) (6), Ru(CF3CO2)2(p‐cymene)·CF3COOAgPCy3 (6a), Ru(CF3CO2)2(PPh3)(p‐cymene) (7), Ru(CF3CO2)2(IMes)(PhNC)3 (8), and Ru(CF3CO2)2(IMesH2)(PhNC)3 (9) (IMes = 1,3‐dimesitylimidazol‐2‐ylidene, IMesH2 = 1,4‐dimesityl‐4,5‐diyhdroimidazolin‐2‐ylidene, PCy3 = tricyclohexylphosphane). X‐ray structures of precatalysts 3 and 6–9 are presented. Compounds 3 and 4 displayed significant ROMP activity, allowing for the controlled, yet nonliving synthesis of the corresponding polymers with polydispersity indices (PDIs) in the range of 1.17–2.14. In all cases the exo isomers of compounds 1 and 2 were polymerized by preference. While poly(endo‐1) was formed in an all‐trans form, poly(exo‐1) and poly(exo‐2) were produced in their cis/trans forms with a cis content of around 40 %. Calculations carried out at the B3LYP/LACVP* level suggest two possible mechanisms for the increased reactivity of the 2,3‐R2‐exo,exo isomers of norborn‐5‐ene‐2,3‐dicarbimido derivatives resulting in the formation of the ROMP‐active RuIV alkylidene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Fast Screening for the Purification of Proteins Using Membrane Adsorber Technology
Authors: Harkensee D. , Kökpinar Ö. , Walter J. , Kasper C. , Beutel S. , Reif O.‐W. , Scheper T. , Ulber R. 
Published: July 2007

AbstractNew membrane systems for the purification of proteins are presented. These disposable devices enable time saving screenings of downstream conditions with a small amount of protein solution. Furthermore, scaling up to the production level is directly possible since devices with effective membrane surfaces from 10 cm2 to 1 m2 are available. Several membranes like ion exchange membranes were investigated for the determination of protein binding capacities. Metal chelate membranes were used for ligand binding, which enables the determination of the membrane systems potential for affinity chromatography. Lysozyme and BSA are chosen for the determination of binding capacities of ion exchange membranes. Furthermore, Con A membranes, suitable for the isolation of glycoproteins, were developed and their binding properties were tested.
At‐line Monitoring of Bioprocess‐Relevant Marker Genes
Authors: Pioch D. , Jürgen B. , Evers S. , Maurer K.‐H. , Hecker M. , Schweder T. 
Published: July 2007

AbstractThe efficiency of an industrial bioprocess depends above all on the physiology of the host organism. Therefore, a rapid and direct analysis of the host's physiology during fermentation processes would be a worthwhile tool to improve the control of such bioprocesses in the future. This could be achieved by monitoring process‐relevant marker genes, the expression of which indicates unfavorable growth conditions. Recently it was shown that electrical DNA‐chips in combination with a magnetic bead‐based sandwich hybridization (BBSH) assay are a suitable alternative technique for a fast analysis of gene expression by monitoring the respective mRNA. In the present study, an improved protocol was established that allows for a shorter but still sensitive detection of specific mRNAs. The presented optimized BBSH protocol in combination with an electrochemical readout system was successfully applied for the analysis of Bacillus licheniformis marker genes indicating glucose‐ (acoA), nitrogen‐ (glnA) and phosphate‐ (phy, pstS) starvation. The expression profiles determined for all marker genes corresponded with the respective real‐time RT‐PCR measurements. Thus, the optimized protocol, in combination with the electrical chip, could provide the basis for a continuous at‐line monitoring of such biomarkers during bioprocesses.
Nonselective DNA damage induced by a replication inhibitor results in the selective elimination of extrachromosomal double minutes from human cancer cells
Authors: Shimizu Noriaki , Misaka Naomi , Utani Koh‐ichi 
Published: July 2007

AbstractGene amplification plays a pivotal role in human malignancy. Highly amplified genes frequently localize to extrachromosomal double minutes (dmin), which usually segregate to daughter cells in association with mitotic chromosomes. We and others had shown that treatment with low‐dose hydroxyurea (HU) results in the elimination of dmin and reversion of the cancer cell phenotype. HU treatment in early S‐phase, when dmin are replicated, results in their detachment from chromosomes at the next M‐phase, leading to the appearance of micronuclei enriched in dmin, followed by their elimination. In this article, we examined the effect of low‐dose HU on the behavior of dmin in relation to DNA damage induction by simultaneously monitoring LacO‐tagged dmin and phosphorylated histone H2AX (γH2AX). As expected, treatment with low‐dose HU induced numerous γH2AX foci throughout the nucleus in early S‐phase, and these rarely coincided with dmin. Most chromosomal γH2AX foci disappeared by metaphase, whereas, unexpectedly, those that persisted frequently associated with dmin. We found that these dmin aggregated, detached from anaphase chromosomes, and apparently formed micronuclei. Because γH2AX foci likely represent DNA double strand breaks (DSBs), the response to DSBs sustained by extrachromosomal dmin appears to be different from that sustained by chromosomal loci, which may explain why DSB‐inducing agents cause the selective elimination of dmin. © 2007 Wiley‐Liss, Inc.
Analysis of multiple SNPs in genetic association studies: comparison of three multi‐locus methods to prioritize and select SNPs
Authors: Heidema A. Geert , Feskens Edith J.M. , Doevendans Pieter A.F.M. , Ruven Henk J.T. , van Houwelingen Hans C. , Mariman Edwin C.M. , Boer Jolanda M.A. 
Published: July 2007

AbstractNonparametric approaches have been developed that are able to analyze large numbers of single nucleotide polymorphisms (SNPs) in modest sample sizes. These approaches have different selection features and may not provide similar results when applied to the same dataset. Therefore, we compared the results of three approaches (set association, random forests and multifactor dimensionality reduction [MDR]) to select from a total of 93 candidate SNPs a subset of SNPs that are important in determining high‐density lipoprotein (HDL)‐cholesterol levels. The study population consisted of a random sample from a Dutch monitoring project for cardiovascular disease risk factors and was dichotomized into cases (low HDL‐cholesterol, n = 533) and non‐cases (high HDL‐cholesterol, n = 545) based on gender‐specific median values for HDL cholesterol. Clearly, all three approaches prioritized three SNPs as important (CETP Taq1B, CETP−629 C/A and LPL Ser447X). Two SNPs with weaker main effects were additionally prioritized by random forests (APOC3 3175 G/C and CCR2 Val62Ile), whereas MTHFR 677 C/T was selected in combination with CETP Taq1B as best model by MDR. Obtained p‐values for the selected models were significant for the set association approach (p =.0019), random forests (p<.01) and MDR (p<.02). In conclusion, the application of a combination of multi‐locus methods is a useful approach in genetic association studies to select a well‐defined set of important SNPs for further statistical and epidemiological interpretation, providing increased confidence and more information compared with the application of only one method. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Efficient intermediate fine mapping: confidence set inference with likelihood ratio test statistic
Authors: Sinha Ritwik , Luo Yuqun 
Published: July 2007

AbstractIn positional cloning of disease causing genes, identification of a linked chromosomal region via linkage studies is often followed by fine mapping via association studies. Efficiency can be gained with an intermediate step where confidence regions for the locations of disease genes are constructed. The confidence set inference [CSI; Papachristou and Lin, 2006b] achieves this goal by replacing the traditional null hypothesis of no linkage with a new set of null hypotheses where the chromosomal position under consideration is in tight linkage with a trait locus. This approach was shown to perform favorably compared with several competing methods. Using the duality of confidence sets and hypothesis testing, CSI was proposed for the Mean test statistics with affected sibling pair data (CSI‐Mean). We postulate that more efficient confidence sets will result if more efficient test statistics are used in the CSI framework. One promising candidate, the maximum LOD score (MLS) statistic, makes maximum use of available identity by descent information, in addition to handling markers with incomplete polymorphism naturally. We propose a procedure that tests the CSI null hypotheses using the MLS statistic (CSI‐MLS). Compared with CSI‐Mean, CSI‐MLS provides tighter confidence regions over a range of single and two‐locus disease models. The MLS test is also shown to be more powerful than the Mean test in testing the CSI null over a wide range of disease models, the advantage being most pronounced for recessive models. In addition, CSI‐MLS is computationally much more efficient than CSI‐Mean. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Heterotopic parathyroid inclusion in a cervical lymph node
Authors: Veras Emanuela , Sturgis Erich M. , Luna Mario A. 
Published: July 2007

AbstractBackground.During the pathologic examination of neck dissection specimens, unexpected findings within the lymph nodes may be discovered. Such findings may include benign epithelial inclusions, a second primary tumor, or chronic inflammatory diseases.Methods.We report a case of a 59‐year‐old man who underwent a laryngectomy and bilateral neck dissection for a right transglottic squamous carcinoma of the larynx. During the procedure, a large lymph node measuring 2.5 × 2.2 × 0.8 cm was found at the right level IV.Results.Histologic examination of the neck dissection specimen revealed benign parathyroid inclusions in the enlarged lymph node. The heterotopic cells expressed parathyroid hormone. This case represents a unique example of heterotopic parathyroid inclusions in a cervical lymph node.Conclusion.Parathyroid tissue should be included in the differential diagnosis of cervical intranodal epithelial inclusions. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Crosslinked hyaluronan with a protein‐like polymer: Novel bioresorbable films for biomedical applications
Authors: Pitarresi G. , Palumbo F. S. , Calabrese R. , Craparo E. F. , Giammona G. 
Published: July 2007

AbstractIn this work, novel hydrogel films based on hyaluronan (HA) chemically crosslinked with the α,β‐poly(N‐2‐hydroxyethyl) (2‐aminoethylcarbamate)‐D,L‐aspartamide (PHEA–EDA) were produced by solution casting method. The goal was to exploit both the biological key role of HA in tissue repair and regeneration, and the versatility of a synthetic protein‐like polymer as the PHEA–EDA, in order to obtain biomaterials with physicochemical and biological properties suitable for a clinical use. By varying the molar ratio between the PHEA–EDA amino groups and HA carboxyl groups, three different films were obtained and characterized. Particularly FTIR, swelling, hydrolysis, and enzymatic degradation studies were performed. In addition, the cytocompatibility of HA/PHEA–EDA hydrogel films was evaluated using human derm fibroblasts, by means of MTT and trypan blue exclusion assays. The high swelling capability, the long‐term hydrolysis resistance, and the resistance to hyaluronidase greater than that of only HA, together with the cell compatibility, have suggested the potential application of these novel HA‐based hydrogel films in the biomedical field of tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008