bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption of sulfuryl fluoride by food commodities
Authors: Sriranjini Venkata‐rao , Rajendran Somiahnadar 
Published: April 2008

AbstractBACKGROUND: The use of sulfuryl fluoride, a structural fumigant for termite and woodborer control, has recently been expanded to treating stored food commodities and food facilities. There is, however, a lack of data on the sorption of sulfuryl fluoride by food commodities. Knowledge about sorption is important in the context of effective treatment and residues.RESULTS: When sulfuryl fluoride was applied at a dose of 50 g m−3 to various food commodities (total 68) with 300 g per replicate in 0.75 L gas wash bottles (fumigation chambers) at 25 ± 1 °C, in most cases (81%) the gas concentrations in the free space of the commodities exceeded 50 g m−3 (range 51–80 g m−3) at the end of 24 h exposure. In chambers without the substrate, an average concentration of 49.7 g m−3 was recorded. About 54% of the commodities showed low‐level ( ≤ 25%) sorption of sulfuryl fluoride, 34% showed medium‐level (26–50%) sorption and only 12% were highly sorptive (>50%). The latter include white oats (terminal gas concentration 17.8 g m−3), some of the decorticated split pulses (24.0–29.3 g m−3), chickpea flour (26.3 g m−3), dried ginger (29.0 g m−3), refined wheat flour (30.3 g m−3) and coriander powder (40.5 g m−3). In unfumigated control commodities, owing to interfering volatiles, Fumiscope® readings in the range 0–13 were noted.CONCLUSION: Sulfuryl fluoride has the advantage of a low or moderate level of sorption with the majority of the food commodities. Copyright © 2008 Society of Chemical Industry
Dielectric function and optical transitions of silicon nanocrystals between 0.6 eV and 6.5 eV
Authors: Mansour M. , En Naciri A. , Johann L. , Grob J. J. , Stchakovsky M. 
Published: April 2008

AbstractIn this work, we report on the study of the dielectric function of nanocrystal silicon (nc‐Si) implanted in a SiO2 matrix on a silicon substrate by spectroscopic ellipsometry (SE). The formed nc‐Si have an average size around 4 nm. The SE measurements are performed at an angle of incidence of 70° in air at room temperature and in the spectral range of 0.6 eV to 6.5 eV. Two models are used to extract the optical responses of nc‐Si: Forouhi–Bloomer formalism and wavelength‐by‐wavelength inversion. The nc‐Si exhibits a significant reduction in the dielectric functions in comparison with the bulk Si. We have observed a reduction of the amplitude of the E1 transition with a very weak shift of its energy position. The transition E2 is characterized by a rather broad peak with an amplitude greater than that of E1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conventional and generalized ellipsometric investigation of isotropic spherical and anisotropic ellipsoidal cobalt nanoparticles
Authors: Gilliot M. , Naciri A. En , Johann L. , Stoquert J. P. , Grob J. J. , Muller D. 
Published: April 2008

AbstractWe propose an optical characterization of complex nanostructured thin layers by spectroscopic ellipsometry. These layers are either made of spherical or ellipsoidal‐shaped cobalt particles buried in a silica thin layer on a silicon substrate. Conventional ellipsometry is used to characterize the optically isotropic layers. It is shown that these implanted layers can be represented by a stack of three sublayers: a Maxwell‐Garnett homogeneous mixture of silica and cobalt clusters sandwiched between two silica sublayers. Ellipsoidal particles are obtained after irradiation of spherical nanostructures by swift heavy ions. In this case, generalized ellipsometry is used to study the uniaxial anisotropic optical effects of these particles. A correlation between the shape anisotropy of the particles and the optical anisotropy of the sample is shown and discussed using generalized Maxwell‐Garnett theory. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Imaging ellipsometry: quantitative analysis
Authors: Asinovski L. , Beaglehole D. , Clarkson M. T. 
Published: April 2008

AbstractImaging ellipsometry (IE) combines spatial resolution of optical microscopy with thin‐film measurement capabilities of ellipsometry. It has gained significant interest in recent years and is been used for a wide range of applications from biotechnology to semiconductor metrology. Traditionally, IE is used either as a qualitative technique – not unlike polarized microscopy or Surface Plasmon Resonance (SPR) – with “ellipsometry images” showing surface topology variation, or as a quasi‐quantitative technique where the change in “ellipsometry images” is used to deduce the change in film thickness. In this paper we give a brief critical review of different measurement systems configurations from the point of view of their fitness to quantitative IE measurement. We discuss the methods of calibration and correction that enable to achieve a truly quantitative IE measurement. We show that a fast and reliable quantitative IE can be practically implemented. It is consistent and can be used in lieu of a classical single point ellipsometry in many applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of surface layers on copper, titanium and tantalum created by methane plasma‐based ion implantation
Authors: Kraft G. , Flege S. , Baba K. , Hatada R. , Ensinger W. 
Published: April 2008

AbstractTwo carbide forming metals, titanium and tantalum, and a typical non carbide former, copper, were treated by methane plasma immersion ion implantation. The polished metal samples were exposed to high voltage pulses at –20 kV in an atmosphere of methane. The lateral distribution of the carbon was investigated via electron probe microanalysis, the depth distribution of the respective metal, carbon and hydrogen was determined by secondary ion mass spectrometry. X‐ray photoelectron spectroscopy in conjunction with argon sputtering showed the evolution of the binding conditions with depth. The phase composition of the samples was also analyzed by glancing incidence X‐ray diffraction. The generated carbon layers exhibited considerable differences depending on the respective substrate. Although there was no carbide formation with the copper samples, some carbon was incorporated into the surfaces. On copper the lateral carbon distributions showed inhomogeneities whereas the appearances of the ones on titanium and tantalum were uniform. The resulting thickness of the carbon layer was not only dependent on the substrate material, but also on the process parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative ab initio study of Cu overlayers on BaTiO3(001) and MgO(001) substrates
Authors: Zhukovskii Yu. F. , Kotomin E. A. , Ellis D. E. 
Published: April 2008

AbstractIn order to compare Cu adhesion upon two kinds of perfect cubic (001) oxide surfaces: (i) TiO2‐ and BaO‐terminated substrates of partly covalent BaTiO3 and (ii) highly ionic MgO substrate, we have performed DFT‐LCAO calculations using a hybrid B3PW Hamiltonian. 2D symmetrical slabs used here contain seven BaTiO3 and five MgO substrate layers covered on both sides by submonolayers of ordered Cu atoms. The Cu periodic coverage density atop the surface oxygen anions was varied from 1/8 to 1/2 monolayer. Copper bonding on the BaTiO3(001) surface has been found to be noticeably stronger than that on ionic MgO(001). Cu adatoms attract the electron density from BaO‐terminated and donate it towards TiO2‐terminated BaTiO3(001) substrates, respectively, by an amount that is about threefold larger than for a Cu/MgO(001) interface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical and topographical characterization of aluminum implanted layers in 4H silicon carbide
Authors: Rambach M. , Bauer A. J. , Ryssel H. 
Published: April 2008

AbstractElectrical parameters and surface topography of aluminum (Al) implanted layers in 4H silicon carbide (SiC) are analyzed. The implantation is conducted for temperatures from room temperature up to 1000 °C. The impact of the post implantation annealing step on the Al implanted layers is investigated for two different annealing systems, a furnace system and a lamp system. The implanted layers are characterized in detail by atomic force microscopy and resistivity measurements. A model based on resistivity data is developed for the determination of activation and compensation and is discussed in order to get a better insight into the influence of the annealing step on the electrical parameters (e.g., hole mobility). In particular, the effect of elevated implantation temperatures on resistivity is identified. Additionally, the surface topography is examined regarding the annealing gas atmosphere. For that, a silicon carbide coated graphite crucible is used to achieve a silicon overpressure during annealing. The effectiveness of this crucible is identified by modeling. Measurements confirm the modeling results, that such a crucible prevents surface degradation only in the lamp system with heating rates of several 1000 K/min, and not in the furnace with heating rates in the range of some 10 K/min. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Femtosecond THz studies of intra‐excitonic transitions
Authors: Huber R. , Schmid B. A. , Kaindl R. A. , Chemla D. S. 
Published: April 2008

AbstractFew‐cycle THz pulses are employed to resonantly access the internal fine structure of photogenerated excitons in semiconductors, on the femtosecond time scale. This technique allows us to gain novel insight into many‐body effects of excitons and reveal key quantum optical processes. We discuss experiments that monitor the density‐dependent renormalization of the binding energy of a high‐density exciton gas in GaAs/Al0.3Ga0.7As quantum wells close to the Mott transition. In a dilute ensemble of 3p excitons in Cu2O, stimulated THz emission from internal transitions to the energetically lower 2s state is observed at a photon energy of 6.6 meV, with a cross section of 10–14 cm2. Simultaneous interband excitation of both exciton levels drives quantum beats, which cause efficient THz emission at the difference frequency. By extending this principle to various other exciton resonances, we develop a novel way of mapping the fine structure by two‐dimensional THz emission spectroscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin‐polarized excitonic emission from quantum dots after electrical injection
Authors: Löffler W. , Hetterich M. , Mauser C. , Li S. , Leuthold J. , Kalt H. 
Published: April 2008

AbstractThe spin of a single electron confined in a semiconductor quantum dot is a possible candidate for a qubit to realize quantum information processing. Here we discuss the initialization of the electron spins in single quantum dots using a semi‐magnetic spin aligner layer. We have succeeded in the concurrent initialization of five quantum dots with near‐unity fidelity. The electron spin is read‐out by observing the polarization of the emitted photons. These originate from excitonic recombination of the electron with an unpolarized hole in the dot. We find dots emitting highly polarized photons over the whole inhomogeneously broadened quantum‐dot ensemble emission spectrum. However, a pronounced dependency between the statistical average of the polarization degree and the quantum‐dot ground‐state energy is found. The influence of charged‐exciton recombination due to donors and defects is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First‐principles study of the (001) surface of cubic Ba0.5Sr0.5TiO3
Authors: Wang Yuan Xu 
Published: April 2008

AbstractWe have theoretically investigated basic properties of the (001) surface of cubic Ba0.5Sr0.5TiO3 (BST) by the plane‐wave pseudopotential method within the local‐density approximation. For the BaSrO2‐terminated surface, the surface‐layer Sr atoms move inward and the surface‐layer Ba atoms move outward. Moreover, the displacement of the surface‐layer Sr atoms is much larger than the surface‐layer Ba atoms. The rumpling of the BaSrO2‐terminated surface is much larger than that of the Ti2O4‐terminated one. The surface state appears in the band structure of the Ti2O4‐terminated surface of BST. Based on the results of the calculated grand thermodynamic potential, only the BaSrO2‐terminated surface can exist in the (001) surface of cubic BST. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contextual shifting: Teachers emphasizing students' academic identity to promote scientific literacy
Authors: Reveles John M. , Brown Bryan A. 
Published: April 2008

AbstractThis research presents a case study of two teachers' emphasis on students' academic identity as a means of facilitating their science literacy development. These cases support a theoretical position that deconstructs the notion of normative science literacy into its constitutive components: (a) being scientific and (b) appropriating its literate practices. Such a perspective views language as a substantive resource for academic identity construction. As such, we utilize a theoretical metaphor of “contextual shifting” to underscore teachers' central role in facilitating student understanding of literate practices associated with school science. Through a cross‐case analysis of two elementary science classrooms, we identified ways that students' academic identities were connected to their affiliation with specific scientific literate practices. Our findings reveal that the teachers in both research classrooms utilized teaching practices designed to afford students opportunities to develop academic identities commensurate with science learning. © 2008 Wiley Periodicals, Inc.Sci Ed92:1015–1041, 2008
Surface initiated‐atom transfer radical polymerization of a sugar methacrylate on gold nanoparticles
Authors: Yoon Kuk Ro , Lee Soo Min , Ramaraj B. , Kim Dong‐Pyo 
Published: April 2008

AbstractFor development of surface‐functionalized gold nanoparticles (GNPs) as cellular probes, we report herein the synthesis of glycoconjugates of GNPs with cyclic sugar methacrylate, 2‐lactobionamidoethyl methacrylate (LAMA). The strategy involves the attachment of an initiator on the nanoparticle surface followed by surface initiated‐atom transfer radical polymerization (SI‐ATRP) of LAMA. SI‐ATRP of LAMA was achieved by reacting a mixture of copper (I) bromide (CuBr), 2,2′‐bipyridine (bpy) and initiator‐bound GNPs in methanol at 20 °C for 12 h. The resultant GNP glycoconjugates were characterized using Fourier‐transform infrared (FT‐IR) spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The FT‐IR spectra of GNP glycoconjugates show IR peaks characteristic of LAMA demonstrating the formation of a LAMA layer on the GNPs' surface. The XPS spectrum of glycoconjugates shows signals due to the presence of carbon (C1s, 288 eV) and oxygen (O1s, 536 eV) along with gold (Au 4f, 100 eV; Au 4p, 743 eV). The increase in diameter of GNPs from 13 to 25 nm measured by SEM further confirms the presence of a LAMA layer on the surface of the GNPs. Considering the biological importance of glycoconjugates, such as cell recognition, cell adhesion and cell growth regulation, the method described herein would be beneficial in many areas such as pathogen detection and biosensors. Copyright © 2008 John Wiley & Sons, Ltd.
Intensive research activity alters short‐term seedling dynamics in a tropical forest
Authors: Comita Liza S. , Goldsmith Gregory R. , Hubbell Stephen P. 
Published: April 2008

AbstractResearchers can have unintentional, yet significant effects on their study systems. We tested for the effects of an intensive tree census on seedling dynamics in a 50‐ha permanent forest plot on Barro Colorado Island, Panama. At the community level, and for different shade‐tolerance guilds, we found no significant differences in seedling recruitment or survival inside compared to controls outside the plot. However, among growth forms, canopy trees and lianas exhibited significantly lower seedling survival inside the plot. Results suggest that intense researcher activity impacts short‐term vegetation dynamics, but effects do not accumulate over time.
Seasonal change in the gut clearance rate of three stonefly species in a Japanese stream
Authors: Miyasaka Hitoshi , Genkai‐Kato Motomi 
Published: April 2008

AbstractWe measured seasonal changes in the gut clearance rate of three stonefly species in a stream. The rate declined with water temperature. Based on the gut clearance rate obtained here, we estimated the half‐reduction time of gut contents and consumption rate of stoneflies on algae. Irrespective of stonefly species, the half‐reduction time in winter (2 days) was twice as long as that in summer (1 day). The areal consumption rates of stoneflies varied depending on species and season. These results imply that the seasonal consumption impact of aquatic insects can be different, despite their daily ration being similar among species.
The Breastfeeding Surgical Patient
Authors: Dumphy Deborah 
Published: April 2008

ABSTRACTIN THE UNITED STATES, more than 10 million women are either pregnant or breastfeeding at any given time. Of the women currently pregnant, over 70% will initially choose to breastfeed.THE NEEDS OF A BREASTFEEDING surgical patient are unique and are best met by a supportive surgical team using evidenced‐based practice. The outcomes of such care will have long‐term effects on both the breastfeeding surgical patient and her infant.EVIDENCED‐BASED PRACTICE resources for care of the breastfeeding surgical patient are scarce. This article applies available resources to the perioperative care of the breastfeeding surgical patient. AORN J 87 (April 2008) 759–766. © AORN, Inc, 2008.
Long-term persistence of Lolium perenne and Trifolium repens in sown hill swards
Authors: WILMAN D. , BYRNE S. A. , OWEN H. Ll. 
Published: April 2008

In order to understand better the factors which influence the persistence or non-persistence of Lolium perenne and Trifolium repens on damp hill land in a wet climate, swards in mid-Wales which had been converted from semi-natural rough grazing (predominantly Molinia caerulea or Nardus stricta or Agrostis/Festuca/Nardus) in 1961–81 were examined in 1982 and 1999, using a point quadrat technique.There was a marked decline between 1982 and 1999 in the proportion of L. perenne in the majority of the study areas. On the other hand, in 1999 the oldest swards (sown 30–38 years before) contained at least as high a proportion of L. perenne (22% of sward on average) as the younger swards (sown 18–29 years before). In two swards sown 25–26 years before, at 390–445 m above sea level, which received 95 kg N/ha per year, L. perenne was 36% of sward. On the other hand, no L. perenne was recorded on three swards which were no longer receiving fertilizer and which were being grazed at a greatly reduced stocking rate. The proportion of T. repens was rather low and declined between 1982 and 1999 (from 10 to 4% of sward on average). The application of more lime and more K and perhaps less N would probably have increased the proportion of T. repens. On at least one farm, the use of MCPA against Cirsium spp. had probably reduced the proportion of T. repens. There were positive correlations between the proportion of L. perenne and the proportions of T. repens and Poa spp. There were negative correlations between L. perenne and each of Agrostis spp., Festuca spp. and Holcus lanatus and also between T. repens and Agrostis spp. The proportion of Poa spp. was positively correlated with exchangeable Ca, nitrate-N and total N in soil and negatively correlated with exchangeable acidity.
Interrelated neuropsychological and anatomical evidence of hippocampal pathology in the at-risk mental state
Authors: Hurlemann R. , Jessen F. , Wagner M. , Frommann I. , Ruhrmann S. , Brockhaus A. , Picker H. , Scheef L. , Block W. , Schild H. H. , Moller-Hartmann W. , Krug B. , Falkai P. , Klosterkotter J. , Maier W. 
Published: April 2008

BackgroundVerbal learning and memory deficits are frequent among patients with schizophrenia and correlate with reduced magnetic resonance imaging (MRI) volumes of the hippocampus in these patients. A crucial question is the extent to which interrelated structural-functional deficits of the hippocampus reflect a vulnerability to schizophrenia, as opposed to the disorderper se.MethodWe combined brain structural measures and the Rey Auditory Verbal Learning Test (RAVLT) to assess hippocampal structure and function in 36 never-medicated individuals suspected to be in early (EPS) or late prodromal states (LPS) of schizophrenia relative to 30 healthy controls.ResultsGroup comparisons revealed bilaterally reduced MRI hippocampal volumes in both EPS and LPS subjects. In LPS subjects but not in EPS subjects, these reductions were correlated with poorer performance in RAVLT delayed recall.ConclusionsOur findings suggest progressive and interrelated structural-functional pathology of the hippocampus, as prodromal symptoms and behaviours accumulate, and the level of risk for psychosis increases. Given the inverse correlation of learning and memory deficits with social and vocational functioning in established schizophrenia, our findings substantiate the rationale for developing preventive treatment strategies that maintain cognitive capacities in the at-risk mental state.
Land markets in late imperial and republican China
Authors: POMERANZ KENNETH 
Published: April 2008

ABSTRACTChina has had very active markets for both the sale and the rental of land since Song times (960–1279), if not longer. By the sixteenth century, most of the institutional arrangements that would characterize these markets until 1949 were in place. These institutions differed sharply from those of emerging land markets in early modern Western Europe: in particular, government played a lesser role in adjudicating disputes over land contracts, and customary arrangements included features that (a) gave some sellers of land claims on purchasers that could last for many years and (b) gave some tenants, especially in South and East China, very strong usufruct rights, which themselves became a form of tradable property. However, despite these and other differences from Western models, Chinese land markets were quite efficient, and provided the incentives needed for a very productive agriculture; secure tenants, for instance, responded to their strong position by behaving like owners and investing heavily in improving the land.
Isolation compliance among university students during a mumps outbreak, Kansas 2006
Authors: SOUD F. A. , CORTESE M. M. , CURNS A. T. , EDELSON P. J. , BITSKO R. H. , JORDAN H. T. , HUANG A. S. , VILLALON-GOMEZ J. M. , DAYAN G. H. 
Published: April 2008

SUMMARYA large mumps outbreak occurred among students at a Kansas university in 2006. To reduce transmission, students with mumps were asked to isolate themselves. We describe isolation measures and student compliance with these measures. Questionnaires were administered to students suspected of having mumps. Of the 132 students instructed to stay isolated, 75% stayed isolated for the number of days recommended and were considered compliant. Case-students told to stay isolated for 1–4 days were more likely to be compliant [86% vs. 66%; adjusted odds ratio (aOR) 3·6, 95% CI 1·4–9·0] than those told to stay isolated for 5–9 days. Those who rated avoiding contact with others during isolation as very important were also more likely to be compliant (83% vs. 60%; aOR 3·6, 95% CI 1·5–8·4) than those who rated the importance lower. In a college setting, it may be difficult to achieve high compliance with guidelines recommending that persons stay isolated for much longer than 4 days.