bluuebunny/crossref_metadata_2025 huggingface dataset:
The spectrum of hand and foot malformations in patients with Greig cephalopolysyndactyly
Authors: Debeer Philippe , Devriendt Koen , De Smet Luc , deRavel Thomy , Gonzalez-Meneses Antonio , Grzeschik Karl-Heinz , Fryns Jean-Pierre
Published: May 2007

Purpose

Greig cephalopolysyndactyly (GCPS) (OMIM 175700), a rare autosomal dominant disorder, is characterized by a distinct combination of craniofacial, hand and foot malformations. The hand and foot malformations often require orthopedic assessment and treatment. The disorder is caused by point mutations or deletions in the GLI3 gene, located on chromosome 7p14.3. Herewith, we review the hand and foot malformations in a cohort of 13 patients referred for genetic testing.

Methods

We reviewed the medical files of 13 patients with GCPS seen at the Center for Human Genetics in Leuven between 2003 and 2005. Clinical, molecular and radiological findings, when available, were recorded.

Results

We identified six different point mutations in the GLI3 gene, two microdeletions and three larger chromosomal deletions. In the hands, preaxial polydactyly was never observed, but the malformations included postaxial polydactyly, broad thumbs, clinodactyly of the thumbs and various degrees of syndactyly. In the feet the spectrum of malformations included preaxial polydactyly, postaxial polydactyly, different degrees of syndactyly and broad halluces. Syndactyly of the toes and hallux abnormalities were present in all patients. Most frequently, syndactyly was present between toes 1–2–3. The broadening of the hallux was either due to a complete or partial duplication of the first toe or to broadening of the distal phalanx. Mental retardation was found in three cases and was associated with a large chromosomal deletion of the GLI3 region.

Conclusion

We found the classic hand and foot malformations associated with GCPS in our cohort of patients. Patients with a large chromosomal deletion had mental retardation, but no structural brain anomalies were found.
Differential role of reactive oxygen species in the activation of mitogen‐activated protein kinases and Akt by key receptors on B‐lymphocytes: CD40, the B cell antigen receptor, and CXCR4
Authors: Lee Rosaline L. , Westendorf Jens , Gold Michael R.
Published: May 2007

Background

Antibodies produced by B‐lymphocytes play a key role in the host defense against infection. The development, survival, and activation of B cell is regulated by multiple receptors including the B cell antigen receptor (BCR), which detects the presence of pathogens, CD40, which binds co‐stimulatory molecules on activated T cells, and chemokines such as SDF‐1 (CXCL12) that play key roles in B cell development and trafficking. Signaling by many receptors results in the generation of reactive oxygen species (ROS) that function as second messengers by regulating the activity of redox‐sensitive kinases and phosphatases. We investigated the role of ROS in signaling by the BCR, CD40, and CXCR4, the receptor for SDF‐1. We focused on activation of ERK, JNK, p38, and Akt, kinases that regulate multiple processes including cell survival, proliferation, and migration.

Results

Using the anti‐oxidants N‐acetyl L‐cysteine (NAC) and ebselen to deplete intracellular ROS, we identified a differential requirement for ROS in the activation of ERK, JNK, p38, and Akt by these receptors. We found that CD40 activated JNK, p38, and Akt via redox‐dependent pathways that were sensitive to ROS depletion by NAC and ebselen. In contrast, BCR‐induced activation of ERK, JNK, p38, and Akt was not affected by ROS depletion. We also found that CXCR4‐induced Akt activation was ROS‐dependent even though activation of the ERK, JNK, and p38 MAP kinases by CXCR4 occurred via ROS‐independent pathways.

Conclusion

The differential requirement for ROS in the activation of ERK, JNK, p38, and Akt by the BCR, CD40, and CXCR4 likely reflects the multiplicity of upstream activators for each of these kinases, only some of which may be regulated in a redox‐dependent manner. These findings support the idea that ROS are important second messengers in B cells and suggest that oxidants or anti‐oxidants could be used to modulate B cell activation.
The neurobiology of love
Authors: Zeki S.
Published: May 2007

Romantic and maternal love are highly rewarding experiences. Both are linked to the perpetuation of the species and therefore have a closely linked biological function of crucial evolutionary importance. The newly developed ability to study the neural correlates of subjective mental states with brain imaging techniques has allowed neurobiologists to learn something about the neural bases of both romantic and maternal love. Both types of attachment activate regions specific to each, as well as overlapping regions in the brain's reward system that coincide with areas rich in oxytocin and vasopressin receptors. Both deactivate a common set of regions associated with negative emotions, social judgment and ‘mentalizing’ that is, the assessment of other people's intentions and emotions. Human attachment seems therefore to employ a push–pull mechanism that overcomes social distance by deactivating networks used for critical social assessment and negative emotions, while it bonds individuals through the involvement of the reward circuitry, explaining the power of love to motivate and exhilarate. Yet the biological study of love, and especially romantic love, must go beyond and look for biological insights that can be derived from studying the world literature of love, and thus bring the output of the humanities into its orbit.
Osteosarcoma cell‐calcium signaling through tissue factor–factor VIIa complex and factor Xa
Authors: Daubie Valéry , De Decker Robert , Nicaise Charles , Pochet Roland
Published: May 2007

The cells responsible for bone formation express protease‐activated receptors. Although serine protease thrombin has been shown to elicit functional responses in bone cells that impact on cell survival and alkaline phosphatase activity, nothing is known about tissue factor, factor VIIa, and factor Xa, the serine proteases that act upstream of thrombin in the coagulation cascade. This paper demonstrates that tissue factor is expressed in the osteoblast‐like cell line SaOS‐2 and, that tissue factor in a factor VIIa‐bound complex induces a transient intracellular Ca2+ increase through protease‐activated receptor‐2. In SaOS‐2 cells, factor Xa induced a sustained intracellular Ca2+ response, as does SLIGRL, a PAR2‐activating peptide, and PAR‐1‐dependent cell viability.
Analysis of the rainbow trout solute carrier 11 family reveals iron import ⩽ pH 7.4 and a functional isoform lacking transmembrane domains 11 and 12
Authors: Cooper C.A. , Shayeghi M. , Techau M.E. , Capdevila D.M. , MacKenzie S. , Durrant C. , Bury N.R.
Published: May 2007

A Xenopus oocyte heterologous expression system was used to characterise iron transport properties of two members of the solute carrier 11 (slc11) protein family isolated from rainbow trout gills. One cDNA clone differed from the trout Slc11α containing an additional 52 bp in the exon between transmembrane domains (TM) 10 and 11. The 52 bp contained a stop codon, resulting in a novel isoform lacking the last two TM (termed slc11γ). Slc11γ and another isoform slc11β, import Fe2+ at external pHs ⩽ to 7.4. Trout slc11β Fe2+ import was more sensitive to inhibition by divalent metals. The novel vertebrate slc11γ isoform functions without TM11 and 12.
The use of bundling in B2B online reverse auctions
Authors: Schoenherr Tobias , Mabert Vincent A.
Published: May 2007

In industrial purchasing a request for quotation (RFQ) can consist of a single item, but is most often composed of two or more products and/or services bundled together. While such bundles are used in offline purchase negotiations, their criticality is heightened in online auctions due to their usual short duration and constrained bidding environment. Despite this importance, little systematic discussion or evaluation has taken place concerning bundling practice, especially as it relates to the individual items included in the bundle, the overall bundle composition, and the resulting supply base and ultimate bundle performance. This study investigates these issues by developing a conceptual model and testing it with a large‐scale survey completed by purchasing professionals practicing bundling in B2B online auctions. Results indicate that crafting a more homogeneous bundle is most important in achieving a successful outcome. Furthermore, more complex or difficult‐to‐specify items do not impact perceived bundle performance, but do influence the supply base that is willing and able to bid on the business.
THE ESTABLISHMENT OF CIVIL REGISTRATION IN SCOTLAND
Authors: CAMERON ANNE
Published: May 2007

An act for registering births, deaths, and marriages was passed for England and Wales in 1836. Scotland, despite evident support for the principle of civil registration there, did not obtain equivalent legislation until 1854 – a paradox that has yet to be fully explained. Eight unsuccessful bills preceded the Scottish act, and this article explores the reasons for their failure. Although the Scottish churches and municipal authorities broadly favoured vital registration, their objections to particular clauses concerning the nomination and payment of registrars, the imposition of fees for registration and penalties for non-registration, and the provision of new administrative facilities repeatedly impeded the bills' progress through parliament. More importantly, four of the bills were linked to measures for reforming the marriage law, which were so offensive to Scottish sensibilities that the registration bills were damned by association. Only by altering these contentious clauses and eschewing any interference with the law of marriage did Lord Elcho's bill of 1854 succeed. The lengthy gestational period preceding the Scottish legislation did, however, result in the compulsory registration of births and deaths, unlike in England, and secured a greater breadth of detail in the Scottish registers.
DAVID LLOYD GEORGE, GEORGES CLEMENCEAU, AND THE 1918 MANPOWER CRISIS
Authors: GREENHALGH ELIZABETH
Published: May 2007

This analysis of the Anglo-French dispute over manpower resources in 1918, in the context of Germany's five Spring offensives on the Western Front, reveals the lack of effective and agreed policies. It examines from an alliance perspective a problem that has not before been so treated in print. After a brief account of the background to the crisis, the article discusses, first, the arguments presented in a French war ministry report on British manpower, and, second, the effects of the problems of transporting and deploying American troops. It goes on to examine some of the questions that were raised in consequence: industrial versus military mobilization; troop densities for a given length of line; and categories of fitness. Both British and French prime ministers spent much time and emotional energy in arguing about these matters. This was a dispute that was as bitter as it was pointless, because ultimately insoluble. Yet the efficient deployment of manpower resources was crucial to victory, and the dispute was dangerous for the maintenance of the coalition.
Microanalysis (Micro-XRF, Micro-XANES, and Micro-XRD) of a Tertiary Sediment Using Microfocused Synchrotron Radiation
Authors: Denecke Melissa A. , Somogyi Andrea , Janssens Koen , Simon Rolf , Dardenne Kathy , Noseck Ulrich
Published: May 2007

Micro-focused synchrotron radiation techniques to investigate actinide elements in geological samples are becoming an increasingly used tool in nuclear waste disposal research. In this article, results using μ-focus techniques are presented from a bore core section of a U-rich tertiary sediment collected from Ruprechtov, Czech Republic, a natural analog to nuclear waste repository scenarios in deep geological formations. Different methods are applied to obtain various, complementary information. Elemental and element chemical state distributions are obtained from μ-XRF measurements, oxidation states of As determined from μ-XANES, and the crystalline structure of selected regions are studied by means of μ-XRD. We find that preparation of the thin section created an As oxidation state artifact; it apparently changed the As valence in some regions of the sample. Results support our previously proposed hypothesis of the mechanism for U-enrichment in the sediment. AsFeS coating on framboid Fe nodules in the sediment reduced mobile groundwater-dissolved U(VI) to less-soluble U(IV), thereby immobilizing the uranium in the sediment.
The M Emission Spectrum of68Erbium
Authors: Dellith Jan , Wendt Michael
Published: May 2007

The M emission spectrum of68Er was reinvestigated using wavelength dispersive spectrometry, with a TAP diffracting crystal. By recording the spectra using the second-order reflection, an improved energy resolution was achieved, which is necessary to resolve the M5O3line from the neighboring α M5N7transition. In addition to the five lines/bands tabulated in the classical paper of Bearden, a number of further lines were observed. These are M1N3, M3O1, M2N1, M5O3, M3N1, and M4N3. For all the lines with an energy below the M5absorption structure (M5O3, M3N1, M4N3, and ζ M5N3), an increasing relative intensity with increasing energy of the exciting electrons,E0, was observed. This dependence has its origin in the fact that these lines are normally absorbed whereas Mα (M5N7) and Mβ (M4N6) are additionally affected by anomalous line-type absorption.
Seasonal changes of the baroclinic wave activity in the northern hemisphere of Mars simulated with a GCM
Authors: Kuroda Takeshi , Medvedev Alexander S. , Hartogh Paul , Takahashi Masaaki
Published: May 2007

Seasonal changes in baroclinic wave activity during northern autumns (Ls = 195–225°) and winters (Ls = 280–300°) are studied with a Martian general circulation model. For the weak dust load, the simulated s = 2 harmonic with 3.1 sols period dominates near the surface, while s = 1 (5.5 sols period) is more prominent at higher altitudes during autumns. In winters, the s = 1 wave has stronger amplitudes and a deep (up to 0.1 mb) vertical structure. These simulations are consistent with observations from MGS. We provide a simple explanation for the planetary wave changes in terms of seasonal variations of the background zonal mean fields. In particular, the observed and simulated significant reduction of the baroclinic wave activity during strong solstitial season dust storms occurs due to the stabilization of the jet stream with respect to baroclinic disturbances, and due to the associated weakening of the wave excitation.
Impact of diapycnal mixing on the saturation state of argon in the subtropical North Pacific
Authors: Ito T. , Deutsch C. , Emerson S. , Hamme R. C.
Published: May 2007

Diapycnal mixing plays an important role in both physical and biogeochemical processes in the oceans, yet the rate of tracer mixing has not been adequately quantified. A theoretical analysis predicts that diapycnal mixing should raise the saturation state of noble gases in the thermocline, at a rate proportional to diapycnal diffusivity. We apply this theory to existing measurements of argon in the ventilated thermocline, where the increase in the saturation state should be proportional to the integrated effect of diapycnal mixing. Combining argon observations from time‐series stations in the North Pacific with freon ventilation age, we tentatively estimate the regional diapycnal diffusivity at 0.35 ± 0.21 10−4 m2s−1. Major sources of uncertainty include spatial and temporal variability and sparse sampling. These uncertainties could be significantly reduced using measurements of several noble gases in a transect from the isopycnal outcrop to the interior gyre.
Thermal cracking and the deep hydration of oceanic lithosphere: A key to the generation of plate tectonics?
Authors: Korenaga Jun
Published: May 2007

The development of transient thermal stress in suboceanic mantle is investigated on the basis of two‐dimensional thermoviscoelastic models incorporating composite rheology appropriate for dry oceanic lithosphere. Thermal stress is shown to be sufficiently high to deeply fracture the coldest part of lithosphere, e.g., to the depth of at least ∼30 km (and possibly down to ∼50 km) in 100‐Ma‐old lithosphere. The release of thermal stress by tension cracking is limited to the vicinity of cracks, and the cascade crack system is suggested to be required given the finite fracture strength of mantle materials. Possible physical and chemical consequences of deep thermal cracking are also discussed. The rheological evolution of oceanic lithosphere is likely to be affected by thermal cracking and subsequent serpentinization, which introduces the localized zones of weakness in the otherwise stiffest part of lithosphere. This localized weakening may help to explain why plate tectonic convection, not stagnant lid convection, operates in Earth's mantle.
Conserving reservoir water storage: An economic appraisal
Authors: Kawashima Shigekazu
Published: May 2007

The depletion of water storage worldwide as a consequence of reservoir sedimentation is a growing problem. Effective sediment management is needed to enhance dam productivity and to extend storage life, thereby avoiding various economic and environmental losses. This paper analyzes reservoir level sediment management from a benefit‐cost perspective and suggests desirable management strategies. Dynamic programming simulation has been used to analyze the long‐term consequences of dam management decisions regarding reservoir sedimentation. The results indicate that doing nothing is likely to lead to inefficiencies and reduce the social welfare in the long run. Alternatively, introducing reservoir level sediment management can mitigate the economic loss due to reservoir sedimentation. Technical innovations that improve sediment removal capabilities and their cost would be vital for conserving the reservoir water storage.
A comparison of land surface model soil hydraulic properties estimated by inverse modeling and pedotransfer functions
Authors: Gutmann Ethan D. , Small Eric E.
Published: May 2007

Soil hydraulic properties (SHPs) regulate the movement of water in the soil. This in turn plays an important role in the water and energy cycles at the land surface. At present, SHPs are commonly defined by a simple pedotransfer function from soil texture class, but SHPs vary more within a texture class than between classes. To examine the impact of using soil texture class to predict SHPs, we run the Noah land surface model for a wide variety of measured SHPs. We find that across a range of vegetation cover (5–80% cover) and climates (250–900 mm mean annual precipitation), soil texture class only explains 5% of the variance expected from the real distribution of SHPs. We then show that modifying SHPs can drastically improve model performance. We compare two methods of estimating SHPs: (1) inverse modeling and (2) soil texture class. Compared to texture class, inverse modeling reduces errors between measured and modeled latent heat flux from 88 to 28 W/m2. Additionally we find that with increasing vegetation cover the importance of SHPs decreases and that the van Genuchten m parameter becomes less important, while the saturated conductivity becomes more important.
Lake abundance, potential water storage, and habitat distribution in the Mackenzie River Delta, western Canadian Arctic
Authors: Emmerton Craig A. , Lesack Lance F. W. , Marsh Philip
Published: May 2007

The complete landscape surface of the active Mackenzie River Delta (13,135 km2) was manually partitioned into discrete lakes (3331 km2), channels (1744 km2), wetlands (1614 km2), and dry floodplain area (6446 km2) via GIS analysis of digital topographic maps recently available for the system. The census total of lakes (49,046) is almost twice as large as prior estimates. Using this new information, total lake volume in the delta during the post river flooding period is estimated as 5.4 km3. Total floodwater storage in the delta lakes and floodplain at peak water levels is estimated at 25.8 km3 and thus is equivalent to about 47% of Mackenzie River flow (55.4 km3 yr−1) during the high‐discharge period of delta breakup. During this period the stored river water can be envisioned in the form of a thin layer of water (2.3 m thick on average) spread out over 11,200 km2 of lakes and flooded vegetation and exposed to 24 h d−1 solar irradiance. Consequently, this temporarily stored water has significant potential to affect the composition of river water flowing to the Beaufort Shelf as it recedes to the river channels after the flood peak.
A global analysis of temporal and spatial variations in continental water storage
Authors: Güntner Andreas , Stuck Jochen , Werth Susanna , Döll Petra , Verzano Kerstin , Merz Bruno
Published: May 2007

While continental water storage plays a key role in the Earth's water, energy, and biogeochemical cycles, its temporal and spatial variations are poorly known, in particular, for large areas. This study analyzes water storage simulated with the Watergap Global Hydrology Model. The model represents four major storage compartments: surface water, snow, soil, and groundwater. Water storage variations are analyzed for the period 1961–1995 with 0.5° resolution, for the major global climate zones, and for the 30 largest river basins worldwide. Seasonal variations are the dominant storage change signal with maximum values in the marginal tropics and in snow‐dominated high‐latitude areas. Interannual variations are associated with large‐scale oscillations such as El Niño Southern Oscillation. The contribution of individual water storage compartments to total storage change varies with the climate region and the timescale under consideration. In most regions, a prominent role of storage variations in surface water bodies is found. Surface water reduces markedly the spatial correlation lengths of water storage fields. The simulation results are evaluated against storage variations of combined atmospheric‐terrestrial water balance studies and other global models. This study contributes to an improved understanding of continental water storage for which the consistent integration of model results and new observations such as from time‐variable gravity data of the Gravity Recovery and Climate Experiment (GRACE) satellite mission is required.
Simulated impacts of climate and land‐cover change on soil erosion and implication for the carbon cycle, 1901 to 2100
Authors: Ito Akihiko
Published: May 2007

The impacts of climatic change and land‐cover change on soil carbon displacement by water erosion were investigated using a global ecosystem carbon cycle model (Sim‐CYCLE) and an empirical erosion model (RUSLE). Simulations considering the climate and land‐cover changes were performed in two phases, from 1901 to 1990 on the basis of historical data, and from 1991 to 2100 using climate projections in the IPCC Forth Assessment Report. During the first phase, total lateral displacement of soil carbon was estimated to be 1.6 ± 0.1 Pg C y−1 with remarkable geographical heterogeneity, and it was gradually intensified in regions where forests were converted into croplands. During the second phase, both projected rainfall and land‐use changes affected the erosion regime in many regions. Consequently, the total amount of soil carbon displacement increased by 32–57%, implying an intensified vulnerability to soil loss and further perturbations in the carbon cycle.
Carbonate‐chloride enrichment in fresh kimberlites of the Udachnaya‐East pipe, Siberia: A clue to physical properties of kimberlite magmas?
Authors: Kamenetsky Vadim S. , Kamenetsky Maya B. , Sharygin Victor V. , Golovin Alexander V.
Published: May 2007

Kimberlites, the deepest terrestrial magmas and the principal source of diamonds, must have low viscosity and high buoyancy, which govern their exceptionally fast transport from mantle depths to the surface. Appreciation of the rheological properties of kimberlite magmas relies on research into their temperatures and compositions. Understanding of the alkali and volatile element budget is central to these studies, but is hampered by contaminated and altered compositions of kimberlites worldwide. Kimberlites of the diamondiferous Udachnaya‐East pipe (Siberia) are exceptionally fresh, with low H2O (<0.5 wt%), but high CO2 (up to 14 wt%), Cl (up to 6 wt%), and alkalies (up to 6 wt% Na2O and 2.0 wt% K2O). After crystallization of olivine the kimberlite melt evolved towards essentially carbonate‐chloride compositions. The groundmass assemblage and compositions of the Udachnaya‐East kimberlite resemble modern halogen‐rich natrocarbonatite lavas from the Oldoinyo Lengai volcano. Rheological measurements on the Oldoinyo Lengai lavas can be used to constrain properties of the kimberlite magma.
Electrical resistivity image of the Jingsutu Graben at the NE margin of the Ejina Basin (NW China) and implications for the basin development
Authors: Becken M. , Hölz S. , Fiedler‐Volmer R. , Hartmann K. , Wünnemann B. , Burkhardt H.
Published: May 2007

Magnetotelluric and transient electromagnetic data reveal the Graben geometry of a NNE striking depression within crystalline basement at the NE margin of the Ejina Basin. We interpret this structure as a Late Mesozoic pull‐apart basin, which is delineated by NNE‐striking normal faults to the east and west. Satellite imagery, SRTM elevation data and previously published geophysical data of our work group suggest that the Graben is part of normal‐fault system that continues at least 140 km farther to the south, thus forming the eastern margin of the Ejina Basin. NNE striking normal faults are atypical in a regional context, where NW striking and ENE striking fault systems prevail. Thus, this feature marks a distinct difference of the Ejina Basin when compared to other basin structures in the China‐Mongolia border region.
Scanning tunneling microscopy/magnetic force microscopy study of ultrathin Fe film on MgO(001) in ultrahigh vacuum
Authors: Lee Jookyung , Dreyer Michael , Krafft Charles , Gomez R. D.
Published: May 2007

Using ultrahigh vacuum high resolution scanning probe microscopy, we investigated the growth and magnetic properties of epitaxial Fe films grown on MgO(001) at different substrate deposition temperatures. On room temperature substrates, Fe forms interconnected grains and for 14nm films produce very large magnetic domains. The domain walls are comprised of a rich variety of Néel, Bloch, and cross ties with interesting characteristics. On high temperature substrates, Fe grows by pyramidal island formation, with well-defined single atomic step terraces. The magnetic properties are dependent on the film thickness, which determines the amount of exchange coupling between the islands. The magnetic structure varies from complex patterns at low coverage to well ordered magnetic ripples and domain walls at higher coverage. The detailed explanation will be shown in this paper.
Pulsed laser ablation deposition of nanocrystalline exchange-coupled Ni11Co11Fe67−xZr7B4Cux (x=0,1) films for planar inductor applications
Authors: Baraskar Ashish K. , Yoon Soack Dae , Geiler Anton , Yang Aria , Chinnasamy C. N. , Chen Yajie , Sun Nian , Vittoria Carmine , Goswami Ramasis , Willard Matthew , Harris Vincent G.
Published: May 2007

Nanocrystalline films of the Ni11Co11Fe67−xZr7B4Cux (x=0,1) composition were deposited on fused quartz substrates by pulsed laser deposition. For the films of Ni11Co11Fe66Zr7B4Cu, the bcc grain size ranged from 5to8nm in the films deposited at substrate temperatures from ambient to 300°C. Films grown at a substrate temperature of 300°C were found to have optimal magnetic properties including minima in the coercivity and ferromagnetic resonance (FMR) linewidth. The magnetic characterization studies showed coercivity Hc<5Oe, 4πMS∼16kG, and in-plane uniaxial anisotropy field (HA)∼25–30Oe. The ferromagnetic resonance linewidth was measured to be 34Oe and zero magnetic field ferromagnetic resonance at ∼2GHz. These properties allow these films to be candidates for magnetic planar inductors operating from 0.5to2GHz.
Room temperature ferromagnetism in Cr-doped In2O3 on high vacuum annealing of thin films and bulk samples
Authors: Kharel P. , Sudakar C. , Sahana M. B. , Lawes G. , Suryanarayanan R. , Naik R. , Naik V. M.
Published: May 2007

We report on the observation of room temperature ferromagnetism in Cr-doped In2O3 bulk samples and spin-coated thin films. The samples showed a clear ferromagnetism above 300K with magnetic moments of 0.008 and 0.22μB∕Cr at 300K for the bulk and thin film, respectively, only after high vacuum (HV) annealing at 600°C. The vacuum annealed Cr-doped In2O3 thin films showed a typical semiconducting behavior with a room temperature resistivity of 0.73Ωcm, while bulk samples were more conducting (23mΩcm). We present systematic investigations on the influence of HV annealing on the carrier concentrations, resistivity, and magnetic properties of the samples.
Magnetic properties and microstructure of ultrathin Co∕Si(111) films
Authors: Chang H. W. , Tsay J. S. , Hung Y. C. , Yuan F. T. , Chan W. Y. , Su W. B. , Chang C. S. , Yao Y. D.
Published: May 2007

The magnetic properties and microstructure of ultrathin Co films grown on a Si(111)-7×7 surface were investigated. The experimental results observed by surface magneto-optic Kerr effect (SMOKE) and scanning tunneling microscopy show that the surface morphological evolution of x ML (monolayer) Co∕Si(111) films is strongly related to their magnetic properties. Due to the formation of a CoSi2 layer, no magnetic signal could be detected by SMOKE for x=2.1. Both longitudinal and polar hysteresis loops appear for 4.2–8.5 ML Co∕Si(111) films because of their rougher surfaces. When the Co thickness is increased to 11 ML, a magnetic hysteresis loop only occurs in the longitudinal configuration, which can be attributed to the contribution of volume anisotropy. After annealing an 11 ML Co∕Si(111) film at 400 and 500K, the surface becomes rougher, inducing magnetic anisotropy on the polar configuration. When the annealing temperature was increased to 600K, however, the Co could react with Si to form a nonmagnetic cobalt silicide compound, and consequently, the hysteresis loops disappeared.
Secondary recrystallization, crystallographic texture and magnetostriction in rolled Fe–Ga based alloys
Authors: Na Suok-Min , Flatau Alison B.
Published: May 2007

The surface-energy-induced secondary recrystallization growth with a specific surface plane can be governed in polycrystalline Fe–Ga alloy doped with sulfur by controlling the segregation of sulfur through conventional rolling and texture annealing. Results that demonstrate the recrystallization, magnetostriction, and selective development of {100}⟨001⟩ and/or {110}⟨001⟩ preferred texture in Fe81.3Ga18.7 plus B (0.5–1.0at.%) and S (∼0.05at.%) alloys are presented in this work. The addition of boron was used to improve ductility by enhancing grain boundary cohesion during rolling. The as-rolled (Fe81.3Ga18.7)+0.5at.% B+0.005at.% S sheet had {100}⟨011⟩ and {111}⟨011⟩ rolling-texture grains. A near {100}⟨001⟩ texture was formed in fully (∼99%) secondary-recrystallized sheet that was annealed at 1200°C for 2h [(3∕2)λS=198ppm], while the texture of mostly (∼80%) secondary-recrystallized sheet annealed at 1100°C for 4h [(3∕2)λS=165ppm] was closer to {110}⟨001⟩. The maximum observed magnetostriction in samples with 0.005at.% S was 220ppm and was obtained as a result of a double annealing, with the resultant texture closer to the ideal {100}⟨001⟩ than the less desirable {110}⟨001⟩. The maximum magnetostriction of 150ppm observed in the (Fe81.3Ga18.7)+1.0at.% B+0.05at.% S sheet resulted when the sheet was annealed at 1200°C for 2h. This sheet had a major texture of {110}⟨112⟩ and minor textures of {110}⟨001⟩∕{100}⟨011⟩.
Ferromagnetic resonance study of magnetic phases in FeNi∕Al∕FeMn∕Al and FeMn∕Al∕FeNi∕Al multilayers
Authors: de Jesus D. R. , Pelegrini F. , Borges J. F. M. , Nascimento V. P. , Saitovitch E. Baggio
Published: May 2007

A comparative ferromagnetic resonance (FMR) study of the magnetic properties of Si(100)[FeNi∕Al∕FeMn∕Al]×10 and Si(100)[FeMn∕Al(6Å)∕FeNi(30Å)∕Al]×20 multilayers is reported. Besides the uniform mode, the parallel and perpendicular FMR spectra of both multilayers also give evidence of additional magnetic phases in the films. The perpendicular FMR spectrum of the first multilayer also shows the presence of a volume spin-wave resonance (SWR) mode, while the spectrum of the second shows the presence of a surface SWR mode. This is attributed to the structural differences between the two multilayers in terms of the thicknesses of the magnetic (FeNi) and nonmagnetic (FeMn and Al) layers.
Improved tunnel magnetoresistance characteristics of magnetic tunnel junctions with a Heusler alloy thin film of Co2MnGe and a MgO tunnel barrier
Authors: Hakamata Shinya , Ishikawa Takayuki , Marukame Takao , Matsuda Ken-ichi , Uemura Tetsuya , Arita Masashi , Yamamoto Masafumi
Published: May 2007

We fabricated magnetic tunnel junctions (MTJs) with a Co-based full-Heusler alloy thin film of Co2MnGe (CMG) and a MgO tunnel barrier. The microfabricated MTJs with a Co-rich CMG film showed relatively high tunnel magnetoresistance ratios of 83% at room temperature and 185% at 4.2K. These values are much higher than those previously obtained for CMG/MgO MTJs with a Co-deficient CMG film.
Magnetotransport properties and spin-torque effects in current perpendicular to the plane spin valves with Co–Fe–Al magnetic layers
Authors: Maat S. , Carey M. J. , Childress J. R.
Published: May 2007

The magnetotransport properties of current perpendicular to the plane giant magnetoresistive spin valves utilizing (CoxFe100−x)100−yAly alloys are investigated over a wide alloy composition range. (Co50Fe50)75Al25 is determined to be the approximate alloy composition that maximizes magnetoresistance. An increase in magnetoresistance from 1.7% for spin valves with standard Co50Fe50 to 3.3% for spin valves with (Co50Fe50)75Al25 is observed when substituting the same “magnetic” thickness in both the reference and the free layers. The spin-diffusion length for (Co50Fe50)75Al25 is determined to be less than approximately 35Å. Spin-torque measurements show that the spin-torque current density threshold is lower in CoFeAl spin valves compared to standard CoFe spin valves.
Infrared spectroscopy of aqueous ionic salt solutions at low concentrations
Authors: Max Jean-Joseph , Gessinger Véronique , van Driessche Caroline , Larouche Pascal , Chapados Camille
Published: May 2007

The analysis by infrared spectroscopy of aqueous solutions of the binary inorganic salts NaI and NaCl and the ternary salts CaCl2 and BaCl2 at concentrations from 1000to2mM was carried out to complement a previous study done at higher concentrations on nine binary salts (alkali halides) and one ternary salt (MgCl2) [J.-J. Max and C. Chapados, J. Chem. Phys. 115, 2664 (2001)]. These salts are completely ionized in aqueous solutions, forming monoatomic species that do not absorb IR but that perturb the surrounding water, modifying its spectrum. The factor analysis of the spectra revealed that all these salt solutions were composed of two water types: pure water and salt solvated water. The authors obtained pure salt solvated water spectra for all the salts using an extrapolation technique. The water types obtained are constant for the binary and ternary salts down to 2mM. For the binary salts, we determine that 5.0 and 4.0 water molecules are solvated to the Na+–Cl− and Na+–I− ion pairs, respectively. These numbers are the same as that obtained at higher concentrations. For the new ternary salts, we find that 6.0 and 8.0 water molecules are solvated to Ca++–(Cl−)2 and Ba++–(Cl−)2 ion pairs, respectively. These numbers are higher than the four water molecules solvated to Mg++–(Cl−)2 ion pairs determined previously, but show a progression that follows their atomic numbers. These results constitute new experimental results on “simple” systems whose molecular organization is still a matter of debate. The IR method that probes the system at the molecular level is a method different than the macroscopic ones that give the activity coefficients. The IR gives direct observation at the molecular level of the strong ion-water interactions that are often neglected and its water structure not considered in macroscopic methods. The present results and their analysis together with those obtained by other methods will facilitate the determination of the organization of these aqueous systems.
Complete and generalized synchronization in a class of noise perturbed chaotic systems
Authors: Chen Zhang , Lin Wei , Zhou Jie
Published: May 2007

In the paper, in light of the LaSalle-type invariance principle for stochastic differential equations, chaos synchronization is investigated for a class of chaotic systems dissatisfying a globally Lipschitz condition with noise perturbation. Sufficient criteria for both complete synchronization and generalized synchronization are rigorously established and thus successfully applied to realize chaos synchronization in the coupled unified chaotic systems. Furthermore, concrete examples as well as their numerical simulations are provided to illustrate the possible application of the established criteria.
A plausible mechanism for the evolution of helical forms in nanostructure growth
Authors: Bandaru P. R. , Daraio C. , Yang K. , Rao A. M.
Published: May 2007

The observation of helices and coils in nano-tube/-fiber (NT/NF) syntheses is explained on the basis of the interactions between specific catalyst particles and the growing nanostructure. In addition to rationalizing nonlinear structure, the proposed model probes the interplay between thermodynamic quantities and predicts conditions for optimal growth. Experimental results on the effect of indium catalyst on affecting the coil pitch in NTs and NFs are presented.
Infrared spectra of N2O–(ortho-D2)N and N2O–(HD)N clusters trapped in bulk solid parahydrogen
Authors: Lorenz Britney D. , Anderson David T.
Published: May 2007

High-resolution infrared spectra of the clusters N2O–(ortho-D2)N and N2O–(HD)N, N=1–4, isolated in bulk solid parahydrogen at liquid helium temperatures are studied in the 2225cm−1 region of the ν3 antisymmetric stretch of N2O. The clusters form during vapor deposition of separate gas streams of a precooled hydrogen mixture (ortho-D2∕para-H2 or HD∕para-H2) and N2O onto a BaF2 optical substrate held at ∼2.5K in a sample-in-vacuum liquid helium cryostat. The cluster spectra reveal the N2O ν3 vibrational frequency shifts to higher energy as a function of N, and the shifts are larger for ortho-D2 compared to HD. These vibrational shifts result from the reduced translational zero-point energy for N2O solvated by the heavier hydrogen isotopomers. These spectra allow the N=0 peak at 2221.634cm−1, corresponding to the ν3 vibrational frequency of N2O isolated in pure solid parahydrogen, to be assigned. The intensity of the N=0 absorption feature displays a strong temperature dependence, suggesting that significant structural changes occur in the parahydrogen solvation environment of N2O in the 1.8–4.9K temperature range studied.
A transient electrical model of charging for Ge nanocrystal containing gate oxides
Authors: Beyer V. , von Borany J. , Klimenkov M.
Published: May 2007

The write performance of a multidot-memory-like structure with respect to hole tunneling is investigated in metal-oxide-semiconductor (MOS) capacitors. The oxide of the MOS structure on p-type Si contains a layer of ion beam synthesized Ge nanocrystals (NC’s) very close to the Si∕SiO2 interface. This structure is modeled in a floating gate-like approach, where the NC’s are considered as individual storage nodes and charged by direct tunneling of holes. Quantum confinement and Coulomb blockade effects of small Ge NC’s (1–6 nm) are discussed and found to be negligible for the present structure. A close agreement between the calculated write characteristics and experimental data clearly confirms the validity of the model. From the simulation results it is predicted that a flatband voltage shift of about ΔVFB=−1 V could be gathered with programming times tprog<1 μs. The write parameters (pulse voltage and duration) for a given ΔVFB value are mainly determined by the distance of the NC’s to the substrate.
Optical properties and ferroelectric engineering of vapor-transport-equilibrated, near-stoichiometric lithium tantalate for frequency conversion
Authors: Hum D. S. , Route R. K. , Miller G. D. , Kondilenko V. , Alexandrovski A. , Huang J. , Urbanek K. , Byer R. L. , Fejer M. M.
Published: May 2007

Near-stoichiometric lithium tantalate (SLT) crystals were produced from congruent lithium tantalate by vapor transport equilibration, and several important optical and ferroelectric properties were measured. The effect of vapor transport conditions and surface preparation on reproducible ferroelectric engineering of SLT has been studied. Control of these effects along with dramatic decreases in the sensitivity to photorefractive damage and 532 nm absorption has allowed near-room-temperature generation of 10 W of continuous wave 532 nm radiation by second harmonic generation from 29 W of 1064 nm radiation in a 4 cm long device.
Fabrication of thick SiGe on insulator (Si0.2Ge0.8OI) by condensation of SiGe∕Si superlattice grown on silicon on insulator
Authors: Balakumar S. , Peng S. , Hoe K. M. , Lo G. Q. , Kumar R. , Balasubramanian N. , Kwong D. L. , Foo Y. L. , Tripathy S.
Published: May 2007

In this work, the authors demonstrate a fabrication methodology for obtaining a thick (∼250nm) high Ge content SiGe-on-insulator (SGOI) film. About 800nm thick low Ge content (∼25%) SGOI film was fabricated by intermixing SiGe and Si through thermal annealing of a superlattice comprising of 60 periods of Si0.7Ge0.3 and Si on silicon-on-insulator (SOI) substrate. A combination of oxidation and annealing processes was used to condense and diffuse the Ge through SiGe film to obtain thick Si0.2Ge0.8OI. It is also found that the oxidation termination is due to residual stress in the thick SGOI layer. The transmission electron microscopy measurements showed that the Si0.2Ge0.8OI film exhibits a single crystalline nature with an orientation that is the same as the starting SOI. X-ray diffraction measurements confirmed that the in-plane strain of the SGOI layers is compressive or nearly relaxed.
980
nm
Bi3Fe5O12∕Sm3Ga5O12 magneto-optical photonic crystal
Authors: Grishin A. M. , Khartsev S. I. , Kawasaki H.
Published: May 2007

Heteroepitaxial all-garnet magneto-optical photonic crystal (MOPC) was fabricated to enhance Faraday rotation at 980nm. MOPC was composed of alternating MO-active Bi3Fe5O12 and transparent Sm3Ga5O12 quarter-wavelength layers grown by rf-magnetron sputtering on Ca,Mg,Zr:Gd3Ga5O12(111) single crystal substrate. High MO performance at the resonance wavelength λ=980nm, specific Faraday rotation θF=−7.3°∕μm, absorption coefficient α=3350cm−1, and MO figure of merit Q=2∣θF∣∕α=43.6° demonstrates feasibility to use bismuth iron garnet MOPCs for application in pump laser diodes, optical amplifiers, modulators, and sensors.
Dual electron donor/electron acceptor character of a conjugated polymer in efficient photovoltaic diodes
Authors: McNeill Christopher R. , Abrusci Agnese , Zaumseil Jana , Wilson Richard , McKiernan Mary J. , Burroughes Jeremy H. , Halls Jonathan J. M. , Greenham Neil C. , Friend Richard H.
Published: May 2007

The authors report efficient photovoltaic diodes which use poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2′,2″-diyl) (F8TBT) both as electron acceptor, in blends with poly(3-hexylthiophene), and as hole acceptor, in blends with (6,6)-phenyl C61-butyric acid methyl ester. In both cases external quantum efficiencies of over 25% are achieved, with a power conversion efficiency of 1.8% under simulated sunlight for optimized F8TBT/poly(3-hexylthiophene) devices. The ambipolar nature of F8TBT is also demonstrated by the operation of light-emitting F8TBT transistors. The equivalent p- and n-type operation in this conjugated polymer represent an important extension of the range of useful n-type materials which may be developed.
(Tetrathiafulvalene)(tetracyanoquinodimethane) as a low-contact-resistance electrode for organic transistors
Authors: Shibata Koji , Wada Hiroshi , Ishikawa Ken , Takezoe Hideo , Mori Takehiko
Published: May 2007

The authors show that source and drain electrodes made of the title metallic organic charge-transfer salt (tetrathiafulvalene)(tetracyanoquinodimethane) [(TTF)(TCNQ)] result in drastic reduction of contact resistance in organic thin-film transistors (TFTs). The contact resistance is estimated by the variable gate-length transfer-line method. Pentacene TFTs with the organic electrodes show smaller contact resistance and larger overall mobility by more than one order than those of bottom-contact Au transistors. The performance is comparable to that of top-contact Au transistors, indicating that (TTF)(TCNQ) is an excellent electrode material for bottom-contact transistors.
Growth and characterization of N-polar InGaN∕GaN multiquantum wells
Authors: Keller S. , Fichtenbaum N. A. , Furukawa M. , Speck J. S. , DenBaars S. P. , Mishra U. K.
Published: May 2007

The properties of N-polar InGaN∕GaN multiquantum wells (MQWs) grown by metal-organic chemical vapor deposition were investigated. Samples grown under optimized conditions exhibited distinct quantum well related emission, smooth surfaces, and abrupt interfaces as evaluated by room temperature photoluminescence, atomic force microscopy, and x-ray diffraction. Enhanced incorporation of indium into N-polar compared to Ga-polar MQW samples was observed for MQWs simultaneously deposited onto the (0001) and (0001¯) GaN-on-sapphire base layers using trimethylindium-to-trimethylgallium-flow-ratios larger than 1.2 during growth. Necessary adjustments of the growth procedure for N polar in comparison with Ga-polar MQWs are described.
Unique antiviral mechanism discovered in anti-hepatitis B virus research with a natural product analogue
Authors: Ying Chunxiao , Li Ying , Leung Chung-Hang , Robek Michael D. , Cheng Yung-Chi
Published: May 2007

Helioxanthin is a natural product that inhibits the replication of a number of viruses. We found that a previously undescribed helioxanthin analogue, 8-1, exhibited potent anti-hepatitis B virus (HBV) activity with little cytotoxicity. 8-1 suppressed both HBV RNA and protein expression, as well as DNA replication of both wild-type and 3TC-resistant virus. Time-course analyses revealed that RNA expression was blocked first after treatment with 8-1, followed by viral proteins, and then DNA. 8-1 inhibited the activity of all HBV promoters by decreasing the binding of hepatocyte nuclear factor 4 (HNF-4), HNF-3, and fetoprotein factor to the precore/core promoter enhancer II region. The amount of HNF-4 and HNF-3 was decreased posttranscriptionally by 8-1 in HBV-producing cells, but not in HBV-negative cells. Therefore, 8-1 suppresses HBV replication by posttranscriptional down-regulation of critical transcription factors in HBV-producing cells, thus diminishing HBV promoter activity and blocking viral gene expression and replication. This mechanism is unique and different from other anti-HBV compounds previously described.