bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of 2‐D nanostructures via metal deposition through a colloidal mask: comparison between thermal evaporation and RF magnetron sputtering
Authors: Ulmeanu Magdalena , Filipescu Mihaela , Medianu Rares V. 
Published: September 2008

AbstractWe use spherical polystyrene beads in the size range from 500 nm ‐ 2 μm to form lithographic masks on surfaces. The masks consist of hexagonally arranged monolayers of these particles formed independently via a self‐organized process upon solvent evaporation. With the help of the so called floating technique, the masks can be transferred to almost any arbitrary substrate. They have been utilized e.g. as masks for vacuum deposition, ion etching, or as masters for micro‐contact‐printing. Current research concentrates on the structure differences when the film deposition was done by thermal evaporation or RF magnetron sputtering. Investigations have been done on different metallic films, with emphasizes on Au thin film. The structures were investigated by atomic force microscopy (AFM) and scanning force microscopy (SEM). The differences in the nanostructures obtained after the removal of the colloidal mask will be evaluated in respect with the thin film deposition technique. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐frequency scalable compact modelling of Si RF‐CMOS technology
Authors: Bazigos Antonios , Bucher Matthias , Sakalas Paulius , Schroter Michael , Kraus Wolfgang 
Published: September 2008

AbstractThe aggressive downscaling of CMOS technologies offers record transit frequencies well above 100 GHz. Efficient RF circuit design, employing such technologies, demands non‐linear, scalable compact models with high accuracy up to high frequencies. EKV3 is an advanced MOSFET model, based on charge sheet theory, that meets such demands. Within this paper, the model is validated against DC and RF measurements up to 30 GHz, for various devices of a modern 180 nm CMOS technology. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pulse electrochemical method for porosification of silicon and preparation of porSi powder with controllable particles size distribution
Authors: Bychto L. , Makushok Y. , Chirvony V. , Matveeva E. 
Published: September 2008

AbstractWe have proposed to use a special electrochemical regime to introduce a preferable grain size into the entirely porosified Si material. This periodic pulse electrochemical regime permits layering of the entire porosified film and defines its preferable partition in the post anodization mechanical treatment. Thus, a preferable grain size is “hidden” in the grown porSi film and is revealed only under additional mechanical treatment like milling. The pore dimension and total porosity are controlled by applied current density at the work pulse and prefabricated (hidden) grain size is introduced during an application of the cut or/and relaxation pulses. We have applied a described procedure to produce a sub‐micrometric grain porSi powder and report results on SEM analysis of the material fabricated in different pulse regimes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fano effect in quasi‐one‐dimensional wires with short‐ or finite‐range impurities
Authors: Vargiamidis Vassilios , Komninou Philomela , Polatoglou Hariton M. 
Published: September 2008

AbstractIn various calculations on the transport properties of quantum wires with impurities, transmission resonances have been found that exhibit the asymmetric Fano line shape. However, short‐ and finite‐range impurities may lead to distinctly different behavior of these resonances. It is shown here that increasing the strength of a shortrange impurity causes a linear increase of the asymmetry parameter and a monotonic decrease of the resonance width. On the other hand, increasing the strength of a finite‐range impurity causes a transformation of an asymmetric Fano resonance into a symmetric antiresonance and subsequently into an “inverted” Fano resonance. This is reflected in an oscillatory behavior of the asymmetry parameter and resonance width. The interference effects that cause this behavior are identified using a coupled‐channel theory. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional quasi‐regular arrays of Ni nanostructures grown within the pores of a porous silicon layer – magnetic characteristics
Authors: Granitzer P. , Rumpf K. , Pölt P. , Šimič S. , Krenn H. 
Published: September 2008

AbstractSelf‐assembled porous media with a quasi‐regular structure offer the possibility to arrange nanoparticles/nanowires in three dimensions. The regular pore‐patterns of the matrix can be achieved in a certain regime, ranging between pore‐diameters of 40 nm up to 100 nm using the same doping density of the silicon substrate. Furthermore the formation of a double‐sided porous layer with a thickness of 30 µm on each side was obtained. These porous silicon membranes with rather regular pore‐arrangements, even fabricated double‐sided, are filled with Ni during electrolytic deposition. The precipitation is performed in using a metal salt solution which is reduced in a cathodic process. The achieved nanocomposite can be varied on the one hand by modification of the nano‐architecture of the silicon template and on the other hand by altering the metal deposition process. Structural characterization of the template and of the deposited metal is performed by scanning electron microscopy, especially by recording the back scattered electrons. EDX‐mapping is performed in order to get chemical information. Different specimens exhibiting various pore‐arrangements and different Ni‐loadings with structures of distinct shape (spheres up to wires) show specific magnetic properties. A relation between the structure and magnetic characteristics is established. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current transport mechanisms in n‐InSe/p‐CdTe heterojunctions
Authors: Gorley P. M. , Grushka Z. M. , Makhniy V. P. , Grushka O. G. , Chervinsky O. A. , Horley P. P. , Vorobiev Yu. V. , González‐Hernández J. 
Published: September 2008

AbstractAnisotype heterojunctions n‐InSe/p‐CdTe were created by deposition over optical contact. The main electrical properties of the devices obtained were investigated. It was found that the current under the forward bias is determined by tunneling‐recombination processes under the low voltage and over‐barrier transport for the high voltage. The reverse current features a tunneling character for the small bias, and becomes significantly amplified for the large applied voltages due to the avalanche multiplication of the carriers caused by impact ionization. Our research has shown that the experimental results can be adequately described in the framework of the known models of current transport for the abrupt anisotype heterojunctions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculated transport coefficients of a nanocrystal in the SET configuration
Authors: Zianni X. 
Published: September 2008

AbstractWe present results of our calculations of transport coefficients for electron tunneling through a nanocrystal in the single electron transistor (SET) configuration. The distinct features of the conductance, the thermopower and the thermal conductance and the relation between them are discussed. In the quantum regime, the energy spectrum of the nanocrystal determines electron transport. Irregular energy spectrum results to non‐periodic sequence of peaks particularly pronounced in the thermal conductance. Quantum confinement is responsible for the small values of the conductance and the thermal conductance. The effect of increasing thermal energy is considered. The validity of Wiedemann‐Franz law is discussed for energies ranging from the quantum regime up to the classical regime. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prediction of hERG Potassium Channel Blockade Using kNN‐QSAR and Local Lazy Regression Methods
Authors: Gunturi Sitarama B. , Archana Kotu , Khandelwal Akash , Narayanan Ramamurthi 
Published: September 2008

AbstractWe have collated hERG inhibition data of 165 compounds from literature and employed two regression procedures, namely, Local Lazy Regression (LLR) and k‐Nearest Neighbor (kNN)‐QSAR regression methods in combination with Genetic Algorithms (GAs) to select significant and independent molecular descriptors and to build robust predictive models. This methodology helped us to derive four, optimal 2D‐ and 3D‐QSPR models, M1–M4, based on five descriptors. Extensive validation tests using leave‐one‐out method and 61 compounds that are not used in the model generation strongly suggest that: (i) models M1 and M2, based on LLR, are very stable and robust; (ii) the model, M2 based on 3‐D descriptors, performs better than the one based on 2‐D descriptors, M1; and (iii) LLR method outperforms kNN regression approach. These results strongly suggest that the combination of GA and LLR method is a promising methodology, to build multiple stable models that are useful in consensus prediction. Further, from the analysis of the physical meaning of the descriptors, used in the best 2‐D and 3‐D descriptor models, M1 and M2, the significant physico‐chemical forces that determine the hERG inhibition profile of small organic compounds are uncovered. Finally, as the models reported herein, are based on computed properties, they appear a valuable tool in virtual screening, where selection and prioritization of candidates is required.
Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization
Authors: Cabañero Ana I. , Recio Jose L. , Rupérez Mercedes 
Published: September 2008

AbstractTwo new procedures for wine ethanol 13C/12C isotope ratio determination, using high‐performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty‐three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15‰, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment. Copyright © 2008 John Wiley & Sons, Ltd.
Geographical traceability of Italian white truffle (Tuber magnatum Pico) by the analysis of volatile organic compounds
Authors: Gioacchini Anna Maria , Menotta Michele , Guescini Michele , Saltarelli Roberta , Ceccaroli Paola , Amicucci Antonella , Barbieri Elena , Giomaro Giovanna , Stocchi Vilberto 
Published: September 2008

AbstractResults are presented that were obtained on the geographic traceability of the white truffle Tuber magnatum Pico. Solid‐phase microextraction coupled to gas chromatography/mass spectrometry (SPME‐GC/MS) was employed to characterize the volatile profile of T. magnatum white truffle produced in seven geographical areas of Italy. The main components of the volatile fraction were identified using SPME‐GC/MS. Significant differences in the proportion of volatile constituents from truffles of different geographical areas were detected. The results suggest that, besides genetic factors, environmental conditions influence the formation of volatile organic compounds. The mass spectra of the volatile fraction of the samples were used as fingerprints to characterize the geographical origin. Next, stepwise factorial discriminant analysis afforded a limited number of characteristic fragment ions that allowed a geographical classification of the truffles studied. Copyright © 2008 John Wiley & Sons, Ltd.
Ion mobility augments the utility of mass spectrometry in the identification of human hemoglobin variants
Authors: Williams Jonathan P. , Giles Kevin , Green Brian N. , Scrivens James H. , Bateman Robert H. 
Published: September 2008

AbstractThe global dispersion of hemoglobin variants through population migration has precipitated a need for their identification. A particularly effective mass spectrometry (MS)‐based procedure involves analysis of the intact globin chains in diluted blood to detect the variant through mass anomalies, followed by location of the variant amino acid residue by direct analysis of the enzymatically digested globins. Here we demonstrate the use of ion mobility separation in combination with this MS procedure to reduce mass spectral complexity. In one example, the doubly charged tryptic peptide from a low abundance variant (4%) occurred at the same m/z value as a singly and a doubly charged interfering ion. In another example, the singly charged tryptic peptide from an α‐chain variant (26%) occurred at the same m/z value as a doubly charged interfering ion. Ion mobility was used to separate the variant ions from the interfering ions, thus allowing the variant peptides to be observed and sequenced by tandem mass spectrometry. Copyright © 2008 John Wiley & Sons, Ltd.
High‐performance liquid chromatography/nano‐electrospray ionization tandem mass spectrometry, two‐dimensional difference in‐gel electrophoresis and gene microarray identification of lymphatic metastasis‐associated biomarkers
Authors: Liu Shuqing , Sun Ming‐Zhong , Tang Jian‐Wu , Wang Zhiqiang , Sun Chengrong , Greenaway Frederick T. 
Published: September 2008

AbstractThe potential biomarkers for the lymphatic metastatic process of mouse hepatocarcinoma were investigated by using two‐dimensional difference in‐gel electrophoresis (2D DIGE), high‐performance liquid chromatography/nano‐electrospray ionization tandem mass spectrometry (HPLC/nESI‐MS/MS) and GeneChip. 2D DIGE was performed to screen and quantify the differentially expressed proteins between two well‐established mouse hepatocarcinoma cell lines, Hca‐F with 75% and Hca‐P with 25% metastasis rate of lymph node potentials. The protein spots in the gel were visualized by the highly sensitive Deep Purple (GE Healthcare) fluorescent stain. Protein identification was obtained for gel spots by HPLC/nESI‐MS/MS analysis with high quality. GeneChip microarray was performed to identify genes differentially expressed at the mRNA level. Seventeen genes including the chloride intracellular channel l, caspase 3, fructose bisphosphatase 2, glutamate dehydrogenase 1, V‐crk sarcoma virus CT10 oncogene homolog, N‐myc downstream regulated gene1, villin2, gelsolin, enoyl coenzyme A hydratase 1, transketolase, vimentin, annexins A5 and A7, keratin complex2 basic gene7 and gene8, lactamase (bata 2) and Ero1‐like protein were found abnormally regulated and expressed concordantly both at the protein and mRNA levels between the two cell lines. More than half of these genes were for the first time revealed to be involved directly in hepatocarcinoma due to the lymphatic metastasis. The interdisciplinary combination of HPLC/nESI‐MS/MS with 2D DIGE and GeneChip techniques opens up the possibility for the biomarker discovery of disease with high confidence. Copyright © 2008 John Wiley & Sons, Ltd.
Job stress in the law enforcement sector: comparing the linear, non‐linear and interaction effects of working conditions
Authors: Noblet Andrew , Rodwell John , Allisey Amanda 
Published: September 2008

AbstractThis study addresses a gap in much of the research involving stress among high‐risk occupations by investigating the effects of linear, non‐linear and interaction models in a law enforcement organization that has undertaken a series of efficiency‐driven organizational reforms. The results of a survey involving 2085 police officers indicated that the demand–control–support model provided good utility in predicting an officer's satisfaction, commitment and well‐being. In particular, social support and job control were closely associated with all three outcome variables. Although the demand × control/support interactions were not identified in the data, there was some support for the curvilinear effects of job demands. The results have implications for the organizational conditions that need to be addressed in contemporary policing environments where new public management strategies have had widespread affects on the social and organizational context in which policing takes place. Copyright © 2008 John Wiley & Sons, Ltd.
Time‐of‐day differences in dopamine clearance in the rat medial prefrontal cortex and nucleus accumbens
Authors: Sleipness Evan P. , Jansen Heiko T. , Schenk James O. , Sorg Barbara A. 
Published: September 2008

AbstractCircadian rhythms influence cocaine‐seeking behavior in rats, and this behavior may be mediated by variability in the rate of extracellular dopamine clearance across the day:night cycle. We used rotating disk electrode voltammetry to examine dopamine clearance and inhibition of clearance by cocaine in the rat medial prefrontal cortex (mPFC) and nucleus accumbens (NAc). Rats were housed under light:dark conditions (LD, 12 h:12 h) or in constant darkness (DD), the latter given just prior to the day of sacrifice. Tissue was collected at 4‐h intervals under LD and DD conditions. Under LD, dopamine clearance in both brain regions was greatest at 4h after lights on. Under DD, there was a blunted but still rhythmic pattern of dopamine clearance across the 24‐h cycle. Cocaine‐induced inhibition of dopamine clearance in the mPFC was not different across the day:night cycle in rats under LD. Paradoxically, under DD, dopamine clearance in the mPFC was enhanced by cocaine at ZT16, 4 h into the subjective night, and only minimally inhibited at other times. In the NAc, cocaine inhibition of dopamine clearance was lowest at ZT4 under LD, and did not vary under DD. We conclude that dopamine clearance varies both in a diurnal and possibly in a circadian manner in the mPFC, and in a diurnal manner in the NAc. These results indicate that light itself may be used to manipulate molecules implicated in drug addiction. Synapse 62:877–885, 2008. © 2008 Wiley‐Liss, Inc.
Dopamine D2Highreceptors moderately elevated by bifeprunox and aripiprazole
Authors: Seeman Philip 
Published: September 2008

AbstractBecause long‐term antipsychotics elicit behavioral dopamine supersensitivity, the present study examined whether 7–9 days administration of partial dopamine D2 agonists with antipsychotic activity, bifeprunox and aripiprazole, could induce biochemical changes that suggest dopamine supersensitivity. In rats, behavioral dopamine supersensitivity is associated with increased dopamine D2Highreceptors in homogenized striata. In control rat striata, bifeprunox and aripiprazole had similarKivalues at D2 receptors. In human cloned D2Long receptors, however, aripiprazole had aKiof 9.6 nM and recognized 41% of the D2 receptors to be in the D2Highstate, while the values for bifeprunox were 1.3 nM and 69%, indicating that bifeprunox had higher potency and efficacy at D2. Nine days of subcutaneously injected bifeprunox (0.25 mg/kg/day) and 7 days of aripiprazole (1.5 mg/kg) increased D2Highreceptors by 102–129% and 108–188%, respectively, although the total population of D2 receptors revealed no significant changes. The increase in D2highreceptors induced by dopamine D2 partial agonists appear to be of smaller magnitude than those seen previously with D2 antagonist antipsychotics. Future research needs to test directly whether long‐term treatment with dopamine partial agonists leads to any behavioral dopamine supersensitivity. Synapse 62:902–908, 2008. © 2008 Wiley‐Liss, Inc.
Effect of varenicline on the acute and repeated locomotor responses to nicotine in rats
Authors: Zaniewska Magdalena , Mccreary Andrew C. , Stefański Roman , Przegaliński Edmund , Filip Małgorzata 
Published: September 2008

AbstractThe objective of this study was to evaluate the efficacy of varenicline, a novel partial agonist at α4β2 and full agonist at α7 nicotinic acetylcholine receptor (nAChR) subtypes, in blocking the locomotor effects of acute or repeated treatments with nicotine (0.4 mg/kg, s.c.) in rats. Varenicline (0.3–3 mg/kg, s.c.) by itself enhanced the basal locomotor activity in naive rats while it had an inhibitory effect on acute nicotine‐induced hyperlocomotion. Varenicline (0.3–3 mg/kg) did not change the nicotine‐evoked conditioned locomotion, but when administered to nicotine‐sensitized rats (0.1 and 1 mg/kg), reduced the expression of nicotine sensitization. In another set of experiments, varenicline (1 mg/kg) administered during the second withdrawal period (days 11–14) to nicotine‐treated rats, attenuated the reestablishment of the expression of nicotine sensitization. Our pharmacological analyses further support the hypothesis that varenicline might be a useful treatment for smoking cessation considering its actions on the locomotor and reinforcing effects of nicotine without inhibition of conditioned locomotion. Synapse 62:935–939, 2008. © 2008 Wiley‐Liss, Inc.
Postsynaptic localization of CB2 cannabinoid receptors in the rat hippocampus
Authors: Brusco Alicia , Tagliaferro Patricia , Saez Trinidad , Onaivi Emmanuel S. 
Published: September 2008

AbstractThe expression of CB2 cannabinoid receptors (CB2‐Rs) in the brain and their neuronal function has now attracted research interest, since we and others have demonstrated the presence of CB2‐Rs in neuronal and glial cells in the brain. In this study, we show the subcellular distribution of CB2‐Rs in neuronal, glial, and endothelial cells in the rat hippocampus using immunohistochemical electron microscopy. Brain sections from the hippocampus were immunolabeled for CB2‐R, visualized, and analyzed by electron microscopy. We found that in neurons, CB2‐R immunoreactivity is present in the cell body as well as in large and medium‐sized dendrites. In the soma, the CB2‐R labeling is associated with the rough endoplasmic reticulum and Golgi apparatus demonstrating that CB2‐Rs are synthesized by hippocampal neurons. CB2‐R labeling in dendrites was observed in the cytoplasm and associated with the plasma membrane near the area of synaptic contact with axon terminals indicating a postsynaptic distribution of these receptors. In CB2‐R immunoreactive glial and endothelial cells, the labeling was also found to be associated with the plasma membrane. These results provide the first ultrastructural evidence that CB2‐Rs are mainly postsynaptic in the rat hippocampus. Synapse 62:944–949, 2008. © 2008 Wiley‐Liss, Inc.