bluuebunny/crossref_metadata_2025_split huggingface dataset:
Damage formation in Ge during Ar+ implantation at 15 K
Authors: Hayes M. , Schroeter A. , Wendler E. , Wesch W. , Auret F. D. , Nel J. M. 
Published: January 2008

AbstractAr+ ions were implanted into Ge samples with (100), (110), (111) and (112) orientations at 15 K with fluences ranging from 1 × 1011 to 1 × 1014 cm−2. The Rutherford backscattering (RBS) technique in the channelling orientation was used to study the damage build‐up in situ. Implantation and RBS measurements were performed without changing the target temperature. The samples were mounted on a four axis goniometer cooled by a close cycle He cryostat. The implantations were performed with the surface being tilted 7° off the ion beam direction to prevent channelling effects. After each 300 keV Ar+ implantation, RBS analysis performed with 1.4 MeV He+ ions. The damage efficiency per ion was found to be Pa =4.5 × 10−14 cm−2. There is no significant difference in the values found for the four different orientations. This, together with the high value (5 times higher than that found in Si), gives rise to the assumption of amorphous pocket formation per incident ion, i.e. direct impact amorphisation, already at low implantation fluences. At higher fluences, when collision cascades overlap, there is a growth of the already amorphised regions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterisation of InAs‐based epilayers by FTIR spectroscopy
Authors: Baisitse T. R. , Forbes A. , Katumba G. , Botha J. R. , Engelbrecht J. A. A. 
Published: January 2008

AbstractIn this paper, infrared reflectance spectroscopy was employed to extract information on the optical and electrical properties of metal organic vapour phase epitaxial (MOVPE) grown InAs and InAsSb epilayers. These epitaxial layers were grown on InAs and GaAs substrates and characterised by infrared reflectance spectroscopy and Hall measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron field emission from nanostructured surfaces of GaN and AlGaN
Authors: Evtukh A. , Yilmazoglu O. , Litovchenko V. , Semenenko M. , Gorbanyuk T. , Grygoriev A. , Hartnagel H. , Pavlidis D. 
Published: January 2008

AbstractThe possibility of high frequency electromagnetic wave generation by field emission based devices has great interest. The wide bandgap materials GaN and AlGaN are very promising for these applications due to low electron affinity and the existence of satellite valleys in conduction band. The results of investigations of the peculiarities of electron field emission from nanostructured surfaces of GaN and AlGaN are presented. Multilayer GaN and AlGaN structures with various levels of layer doping on sapphire and bulk GaN substrates were used as initial wafers. The surface of the upper layers was nanostructured by photoelectrochemical etching in water solution of KOH. Intensive electron field emission into vacuum was observed and explained by low electron affinity and electric field enhancement on surface nanowires. A decrease of the slope in the Fowler‐Nordheim characteristics was revealed. The changing slope suggests a lowering of effective work function. It is caused by electron heating and transfer into an upper satellite valley with lower electron affinity. A theory was developed for the observed phenomena and interpretation of results. It is baseed on electron intervalley transition upon heating and on energy band reconstruction of the surface of the nanowires due to quantum size‐confinement effect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of growth conditions on grown‐in defect formation and luminescence efficiency in Ga(In)NP epilayers grown by molecular‐beam epitaxy
Authors: Dagnelund D. , Buyanova I. A. , Chen W. M. , Utsumi A. , Furukawa Y. , Wakahara A. , Yonezu H. 
Published: January 2008

AbstractA detailed study of the impact of different growth conditions (i.e. ion bombardment, nitrogen flow and In content) on the defect formation in Ga(In)NP epilayers grown on GaP substrates by solid‐source molecular beam epitaxy is performed. Reduced nitrogen ion bombardment during the growth is shown to significantly reduce formation of defects acting as competing recombination centers, such as a Ga interstitial defect and other unidentified defects revealed by optically detected magnetic resonance. Further, high nitrogen flow is found to be even more effective than the ion bombardment in introducing the defects. The incorporation of In by 5.1% is, on the other hand, found not to affect the introduction of defects. The results provide a useful insight into the formation mechanism of the defects that will hopefully shed light on a control of the defect introduction in the alloys by optimizing growth conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band gap energy fluctuations in InGaN films grown by RF‐MBE with changing nitrogen supply rate investigated by a piezoelectric photothermal spectroscopy
Authors: Komaki H. , Shimohara T. , Sakai K. , Katayama R. , Onabe K. , Fukuyama A. , Ikari T. 
Published: January 2008

AbstractIn this study, non‐radiative recombination center in InGaN films with varying III/N ratio grown by rf‐molecular beam epitaxy was investigated directly by piezoelectric photothermal spectroscopy (PPTS). To clarify the influence of the III/N supply ratio during the InGaN layer growth, the nitrogen flow rate was changed from 1.0 to 2.0 sccm. Since metallic‐indium droplets and phase separation were observed for the samples grown by low nitrogen flow rate, it was found that these have been grown under a group‐III‐rich condition. With increasing nitrogen flow rate, the indium content in InGaN films increased. The estimated non‐radiative recombination edges determined from PPTS method (PPT edge) red‐shifted with increasing the nitrogen flow rate. The energy difference between estimated band edge and the PPT edges increased with increasing flow rate under group‐III rich condition, and became saturated under the N‐rich condition. It is considered that the existence of the phase separation is related to this behavior. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hopping currents in the intrinsic region of III‐N‐V quantum well structures in the tight binding approximation
Authors: Varonides Argyrios C. , Spalletta Robert A. 
Published: January 2008

AbstractWe calculate for the first time Nearest Neighbor Hopping (NNH) current densities for III‐N‐V heterostructures embedded in the intrinsic layer of p‐i‐n geometries. We start from a general formalism that relates the density of states in individual wells with the transition probabilities from a quantum well state to a neighboring one, in a superlattice‐geometry. In the process, we find and point out the fact that there is zero hopping‐current without Fermi level splitting for any two consecutive layers.). We then relate the eigen‐energies with the transition probabilities and conclude that NNH ‐currents are of the order of 0.06 mA/cm2 at the most and in room temperatures, and depend on (a) device geometry (b) temperature (c) conduction band discontinuity and (d) Fermi level splitting. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of the angular distribution of the surface excitation parameter for Ti, Fe, Cu, Pd, Ag, and Au
Authors: Pauly N. , Tougaard S. 
Published: January 2008

AbstractWe define surface excitation parameter (SEP) as the change in excitation probability of an electron caused by the presence of the surface in comparison with an infinite medium, and we calculate the angular dependence of the SEP for different metals (Ti, Fe, Cu, Pd, Ag, and Au), for angles to the surface normal between 10° and 70° and for different energies. The calculations are based on a study of energy‐differential inelastic electron scattering cross‐sections obtained from the software Quantitative analysis of Electron Energy Losses at Surfaces (QUEELS) valid for reflection‐electron‐energy‐loss spectroscopy (REELS). The intensity of the surface excitation is isolated from the total spectrum by subtracting the volume component for an infinite medium and the SEP is deduced from it. Copyright © 2008 John Wiley & Sons, Ltd.
Quantification issues of trace metals analysis on silicon oxide and nitride films by using VPD‐ICP‐MS and VPD‐GF‐AAS
Authors: Yeh Ming‐Peng , Hsien Casey , Huang Cheng‐Sung , Lin Ter‐Chuan 
Published: January 2008

AbstractVapor phase decomposition (VPD) is a pretreatment technique for collecting trace metal contaminants on the surface of a Si wafer. Such trace metals can be identified and quantified by inductively coupled plasma mass spectrometry (ICP‐MS) or graphite furnace atomic absorption spectroscopy (GF‐AAS). However, the analytical results can be influenced by the Si‐matrix in the VPD samples. This article discusses the approaches to eliminate the interference caused by Si‐matrix. When the thickness of oxide film on wafer surface is less than 100 Å, the quantification results of ICP‐MS analysis will not be affected by Si‐matrix in the VPD samples. Except this, the Si‐matrix must be removed before analysis. An improved heating pretreatment approach has been adopted successfully to eliminate the Si‐matrix. For GF‐AAS analysis, the Si‐matrix will influence the sodium and aluminum analyses. Adding HNO3 to the graphite furnace tubing after sample injection could also eliminate the interference caused by the Si‐matrix. The method detection limits (MDLs) of VPD‐GF‐AAS and VPD‐ICP‐MS range from 0.04 to 0.55 × 1010 atoms cm−2 and 0.05 to 1.73 × 109 atoms cm−2, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
Use of Iodine as a Tool to Understand Wheat Starch Pasting Properties
Authors: Saibene Debora , Seetharaman Koushik 
Published: January 2008

AbstractThe ability of iodine to bind amylose has been used to understand a variety of structural and functional aspects of starch in food systems. In this study, the changes in starch granule swelling, polymer leaching and their relationship to pasting properties was investigated by adding iodine to the starch slurry at either room temperature or 95°C. The objective of the study was to investigate the contribution of leached and solubilized starch polymers on the pasting behavior of wheat starch. The addition of very small amounts of iodine (0.1%, dry basis, db) at room temperature increased peak and final pasting viscosities as compared to when no iodine was added. Further increases in iodine concentration resulted in a decrease in peak and final pasting viscosities. The amount of iodine required to completely inhibit granule swelling was more than that required to minimize amylose leaching from the granule. Adding increasing amounts of iodine at 95°C to the starch slurry resulted in the gradual decrease in peak and final pasting viscosities. The contrasting effects of iodine on paste viscosity behavior when added at room temperature or at 95°C suggest that the contribution of extra‐granular amylose on the setback viscosity is minimal and a larger proportion of amylose is retained in the intragranular spaces.
Effect of Ionic Strength on the Interfacial and Bulk Properties of Unsymmetrical Bolaamphiphiles
Authors: Jiang Yurong , Xu Zhigang , Luan Jimei , Liu Pingqin , Qiao Weihong , Li Zongshi 
Published: January 2008

AbstractBy performing measurements of the equilibrium surface tensions of electrolyte solutions of three unsymmetrical bolaamphiphiles, each of which has an aromatic ring and a ω‐carboxyalkyl chain in its molecular structure, we conclude that the carboxyl and sulfonate groups at both ends of the molecule—which enter the solution while the hydrophobic chain extends into the air—can force these surfactants to adopt a looped configuration which looks like the letter “U” upside‐down, resulting in regular arrangements at the air/water interface and micelles in bulk solution. Surface tension measurements of these surfactants as a function of added salt reveal the limiting surface tension to be less sensitive to the ionic strength in LiCl solution and significantly sensitive to divalent Ca2+ and Mg2+ ions in hard water. This result reveals that the looped configuration of the molecule is the dominant factor in determining whether the molecules of this surfactant are sensitive to ionic strength or not. This paper also reports briefly on the effect of the interactions of divalent Ca2+ and Mg2+ ions with unsymmetrical bolaamphiphiles on the turbidity of hard water. These results suggest that the interactions of divalent Ca2+ and Mg2+ ions with carboxyl groups are strong, and the two breaks in the surface tension curves disappear. In 200 ppm hard water, the turbidity appears over just a small range of surfactant concentrations, showing that the presence of the Ca2+ and Mg2+ ions has little effect on the application of these surfactants.
X-pinch experiments with pulsed power generator (PPG-1) at Tsinghua University
Authors: Liu R. , Zou X. , Wang X. , He L. , Zeng N. 
Published: January 2008

AbstractThe test on an X-pinch device powered by a pulsed power generator (PPG-I) was carried out step by step. In the first step, a brass rod of 6 mm in diameter was used as a load to replace the X-pinch load. The results of the first step shows that all the current, about 200 kA in amplitude, output from PPG-I flows through the load and no breakdown or flashover in vacuum of the load section happens. The waveform of the current from PPG-I measured with a wall resistor coincides exactly with that of the load current measured with a Rogowski coil, which indicates that the calibrations of the wall resistor and Rogowski coil are correct. In the second step, an X-pinch load made of two molybdenum wires of 40 µm in diameter was used. It was found that the distance between the cathode and anode affects considerably the operation of the device. While breakdown in vacuum happens for the distance equal to 30 mm, it works very well for the distance equal to 16 mm. The reason for this phenomenon was given.
International foodborne outbreak ofShigella sonneiinfection in airline passengers
Authors: GAYNOR K. , PARK S. Y. , KANENAKA R. , COLINDRES R. , MINTZ E. , RAM P. K. , KITSUTANI P. , NAKATA M. , WEDEL S. , BOXRUD D. , JENNINGS D. , YOSHIDA H. , TOSAKA N. , HE H. , CHING-LEE M. , EFFLER P. V. 
Published: January 2008

SUMMARYDuring 22–24 August 2004, an outbreak ofShigella sonneiinfection affected air travellers who departed from Hawaii. Forty-seven passengers with culture-confirmed shigellosis and 116 probable cases who travelled on 12 flights dispersed to Japan, Australia, 22 US states, and American Samoa. All flights were served by one caterer. Pulsed-field gel electrophoresis of all 29S. sonneiisolates yielded patterns that matched within one band. Food histories and menu reviews identified raw carrot served onboard as the likely vehicle of infection. Attack rates for diarrhoea on three surveyed flights with confirmed cases were 54% (110/204), 32% (20/63), and 12% (8/67). A total of 2700 meals were served on flights with confirmed cases; using attack rates observed on surveyed flights, we estimated that 300–1500 passengers were infected. This outbreak illustrates the risk of rapid, global spread of illness from a point-source at a major airline hub.
Comparison of symptoms and treatment outcomes between actively and passively detected tuberculosis cases: the additional value of active case finding
Authors: DEN BOON S. , VERVER S. , LOMBARD C. J. , BATEMAN E. D. , IRUSEN E. M. , ENARSON D. A. , BORGDORFF M. W. , BEYERS N. 
Published: January 2008

SUMMARYPassive detection of tuberculosis (TB) cases may lead to delay in treatment which may contribute to increased severity of disease and mortality. Active case finding may be an alternative. In a community survey in Cape Town, South Africa, we actively detected 27 bacteriologically positive TB cases and compared those with 473 passively detected TB cases. Seven of 27 (26%) actively detected TB cases did not start treatment within 2 months and were considered initial defaulters. Those who did start treatment had similar treatment success rates as passively detected TB cases (both 80%) (OR 1·01, 95% CI 0·33–3·09). Passively detected cases reported the presence of the symptoms cough (OR 3·72, 95% CI 1·47–9·39), haemoptysis (OR 3·20, 95% CI 1·03–9·93), night sweats (OR 3·35, 95% CI 1·40–7·99), fever (OR 4·28, 95% CI 1·21–15·14), and weight loss (OR 11·14, 95% CI 4·17–29·74) more often than those detected actively. We conclude that although TB cases detected by a community survey are less symptomatic and are prone to a high initial default rate, active case finding can potentially identify a substantial portion of the existing caseload at an earlier stage of disease, thereby reducing the risk of transmission.
Inferior rabies vaccine quality and low immunization coverage in dogs (Canis familiaris) in China
Authors: HU R. L. , FOOKS A. R. , ZHANG S. F. , LIU Y. , ZHANG F. 
Published: January 2008

SUMMARYHuman rabies in China continues to increase exponentially, largely due to an inadequate veterinary infrastructure and poor vaccine coverage of naive dogs. We performed an epidemiological survey of rabies both in humans and animals, examined vaccine quality for animal use, evaluated the vaccination coverage in dogs, and checked the dog samples for the presence of rabies virus. The lack of surveillance in dog rabies, together with the low immunization coverage (up to 2·8% in rural areas) and the high percentage of rabies virus prevalence (up to 6·4%) in dogs, suggests that the dog population is a continual threat for rabies transmission from dogs to humans in China. Results also indicated that the quality of rabies vaccines for animal use did not satisfy all of the requirements for an efficacious vaccine capable of fully eliminating rabies. These data suggest that the factors noted above are highly correlated with the high incidence of human rabies in China.
Modelling a national programme for the control of foodborne pathogens in livestock: the case of Salmonella Dublin in the Danish cattle industry
Authors: JORDAN D. , NIELSEN L. R. , WARNICK L. D. 
Published: January 2008

SUMMARYA ‘virtual hierarchy’ model is described for studying the spread of pathogens between herds of livestock. This novel approach to simulating disease has animals, herds, and geographic regions in a national livestock industry arranged as a hierarchy of objects in computer memory. Superimposed on all objects is an infection–recovery cycle, a control programme, and surveillance based on test results and animal movement. The model was applied to predicting progress in the control of Salmonella Dublin in the Danish dairy cattle industry over a 10-year period. More frequent testing of bulk tank milk for antibodies to S. Dublin was less effective than improved herd biosecurity. Restricting cattle movement between regions provided a strong benefit to those regions initially with a low prevalence of infection. Enhanced control within infected herds was of intermediate benefit. A combination of strategies was highly effective although cost and feasibility of this option needs further exploration.
Building Rules on Top of Ontologies for the Semantic Web with Inductive Logic Programming
Authors: LISI FRANCESCA A. 
Published: January 2008

AbstractBuilding rules on top of ontologies is the ultimate goal of the logical layer of the Semantic Web. To this aim, an ad-hoc markup language for this layer is currently under discussion. It is intended to follow the tradition of hybrid knowledge representation and reasoning systems, such as$\mathcal{AL}$-log that integrates the description logic$\mathcal{ALC}$and the function-free Horn clausal languageDatalog. In this paper, we consider the problem of automating the acquisition of these rules for the Semantic Web. We propose a general framework for rule induction that adopts the methodological apparatus of Inductive Logic Programming and relies on the expressive and deductive power of$\mathcal{AL}$-log. The framework is valid whatever the scope of induction (description versus prediction) is. Yet, for illustrative purposes, we also discuss an instantiation of the framework which aims at description and turns out to be useful in Ontology Refinement.
Toward a new generation of ice sheet models
Authors: Little Christopher M. , Oppenheimer Michael , Alley Richard B. , Balaji Venkatramani , Clarke Garry K. C. , Delworth Thomas L. , Hallberg Robert , Holland David M. , Hulbe Christina L. , Jacobs Stan , Johnson Jesse V. , Levy Hiram , Lipscomb William H. , Marshall Shawn J. , Parizek Byron R. , Payne Antony J. , Schmidt Gavin A. , Stouffer Ronald J. , Vaughan David G. , Winton Michael 
Published: January 2008

Large ice sheets, such as those presently covering Greenland and Antarctica, are important in driving changes of global climate and sea level. Yet numerical models developed to predict climate change and ice sheet‐driven sea level fluctuations have substantial limitations: Poorly represented physical processes in the ice sheet component likely lead to an underestimation of sea level rise forced by a warming climate.The resultant uncertainty in sea level projections, and the implications for climate policy, have been widely discussed since the publication of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) [IPCC, 2007]. The assessment report notes that current models do not include “the full effects of changes in ice sheet flow, because a basis in published literature is lacking.” The report also notes that the understanding of rapid dynamical changes in ice flow “is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.”
Selective bias in temporal bisection task by number exposition
Authors: Vicario Carmelo Mario 
Published: January 2008

AbstractTemporal experience can be modulated by a number of environmental factors such as quantity. Here I show that merely looking at numbers causes a bias in imaginative (but not perceptual) time bisection task that depends on the number’s magnitude. This suggests that automatic shifts of spatial attention to the left and right side, as a result of exposure to numbers, modulates temporal as well as spatial behaviour (2,3,4). This finding suggests that the representation of time and space produce certain patterns in neural maps that are decoded by means of the similar neural mechanisms.
Prototype chicken galectins revisited: characterization of a third protein with distinctive hydrodynamic behaviour and expression pattern in organs of adult animals
Authors: Kaltner Herbert , Solís Dolores , Kopitz Jürgen , Lensch Martin , Lohr Michaela , Manning Joachim C. , Mürnseer Michael , Schnölzer Martina , André Sabine , Sáiz José Luis , Gabius Hans-Joachim 
Published: January 2008

Prototype galectins are versatile modulators of cell adhesion and growth via their reactivity to certain carbohydrate and protein ligands. These functions and the galectins' marked developmental regulation explain their attractiveness as models to dissect divergent evolution after gene duplication. Only two members have so far been assumed to constitute this group in chicken, namely the embryonic muscle/liver form {C-16 or CLL-I [16 kDa; chicken lactose lectin, later named CG-16 (chicken galectin-16)]} and the embryonic skin/intestine form (CLL-II or C-14; later named CG-14). In the present study, we report on the cloning and expression of a third prototype CG. It has deceptively similar electrophoretic mobility compared with recombinant C-14, the protein first isolated from embryonic skin, and turned out to be identical with the intestinal protein. Hydrodynamic properties unusual for a homodimeric galectin and characteristic traits in the proximal promoter region set it apart from the two already known CGs. Their structural vicinity to galectin-1 prompts their classification as CG-1A (CG-16)/CG-1B (CG-14), whereas sequence similarity to mammalian galectin-2 gives reason to refer to the intestinal protein as CG-2. The expression profiling by immunohistochemistry with specific antibodies discerned non-overlapping expression patterns for the three CGs in several organs of adult animals. Overall, the results reveal a network of three prototype galectins in chicken.