bluuebunny/crossref_metadata_2025 huggingface dataset:
Tectonic history of northern New Caledonia Basin from deep offshore seismic reflection: Relation to late Eocene obduction in New Caledonia, southwest Pacific
Authors: Collot Julien , Geli Louis , Lafoy Yves , Vially Roland , Cluzel Dominique , Klingelhoefer Frauke , Nouzé Hervé
Published: December 2008

New, high‐quality multichannel seismic reflection data from the western New Caledonia offshore domain allow for the first time the direct, continuous connection of seismic reflectors between the Deep Sea Drilling Project 208 drill hole on the Lord Howe Rise and the New Caledonia Basin. A novel seismic interpretation is hence proposed for the northern New Caledonia Basin stratigraphy, which places the Eocene/Oligocene unconformity deeper than previously thought and revisits the actual thickness of the pre‐Oligocene sequences. A causal link is proposed between the obduction of the South Loyalty Basin over New Caledonia (NC) and the tectonic history of the northern New Caledonia Basin. Here it is suggested that as the South Loyalty Basin was being obducted during early Oligocene times, the NC Basin subsided under the effect of the overloading and underthrusted to accommodate the compressional deformation, which resulted in (1) the uplift of the northern Fairway Ridge and (2) the sinking of the western flank of New Caledonia. This event also had repercussions farther west with the incipient subsidence of the Lord Howe Rise.
Interpretation of water retention field measurements in relation to hysteresis phenomena
Authors: Canone Davide , Ferraris Stefano , Sander Graham , Haverkamp Randel
Published: December 2008

Knowledge of the soil water retention function is fundamental to quantifying the flow of water and dissolved contaminants in the vadose zone. This function is usually determined by fitting a particular model (see, for example, van Genuchten (1980) or Brooks‐Corey (1964)) to observed retention points. Independent of the model chosen, interpretation and identification of the water retention parameters are subjective and prone to error, particularly as it is common that the hysteresis history in measured data points is unknown. Experimental data sets from three different field soils are used to clearly demonstrate how the lack of hysteresis knowledge can lead to an inconsistent and incorrect interpretation of the retention data, and therefore to the incorrect estimation of soil hydraulic parameters. By using a hysteresis model to interpret this same data set, it is easily shown that consistent and reliable estimates of soil retention parameters can be obtained. This is true for any physically based hysteresis model. The difficulty in reading water retention measurements may be evident when both drying and wetting data are measured. However, in practice, users are rarely aware of this problem since generally only one set of drying data is measured, making comparison impossible. Such erratic interpretation of water retention field data in the literature will be probably far more common than expected.
Hermeneutics and Psychology: A Review and Dialectical Model
Authors: Sandage Steven J. , Cook Kaye V. , Hill Peter C. , Strawn Brad D. , Reimer Kevin S.
Published: December 2008

The authors encourage psychologists to transcend the simple but often made a contrast of quantitative and qualitative epistemologies by reissuing a call to consider a hermeneutical realist perspective. The authors recognize that such calls are not new and have largely gone unheeded in the past, perhaps because of how a more radical hermeneutical perspective has been conceptualized and communicated. Rooted in P. Ricoeur's (1981) philosophy of distanciation, the authors propose a dialectic of understanding and explanation that values both quantitative and qualitative methodologies by (a) tracing the philosophical development of hermeneutics as a paradigm for knowing, (b) demonstrating useful hermeneutical applications to psychology as a whole and to some specific subdisciplines, and (c) illustrating how a hermeneutic realist approach is beneficial to the multicultural study of virtue.
uPA Modulates the Age-Dependent Effect of Brain Injury on Cerebral Hemodynamics through LRP and ERK MAPK
Authors: Armstead William M , Cines Douglas B , Bdeir Khalil H , Bdeir Yasmina , Stein Sherman C , Higazi Abd Al-Roof
Published: December 2008

We hypothesized that urokinase plasminogen activator (uPA) contributes to age-dependent early hyperemia after fluid percussion brain injury (FPI) by activating extracellular signal-related kinase (ERK) mitogen-activated protein kinase (MAPK), leading to histopathologic changes in the underlying cortex. Both cerebrospinal fluid (CSF) uPA and phosphorylation of CSF ERK MAPK was increased at 1 min after FPI in newborn pigs, but was unchanged in juvenile pigs. uPA and phosphorylated ERK MAPK, detectable in sham piglet brain by immunohistochemistry, was markedly elevated and associated with histopathology 4 h after FPI in the newborn but there was minimal staining and histopathology in the juvenile. EEIIMD, a peptide derived from PA inhibitor-1 that does not affect proteolysis, blunted FPI-induced phosphorylation of ERK MAPK. FPI produced pial artery dilation and increased cerebral blood flow at 1 min after insult in the newborn, but not in the juvenile. Antilipoprotein-related protein (LRP) antibody, EEIIMD, a soluble uPA antagonist, and the ERK MAPK antagonist U 0126 inhibited FPI-associated hyperemia. These data indicate that uPA is upregulated after FPI and produces an age-dependent early hyperemia followed by histopathology through an LRP- and ERK MAPK-dependent pathway.
Controlling complexity and water penetration in functional de novo protein design
Authors: Anderson J.L. Ross , Koder Ronald L. , Moser Christopher C. , Dutton P. Leslie
Published: December 2008

Natural proteins are complex, and the engineering elements that support function and catalysis are obscure. Simplified synthetic protein scaffolds offer a means to avoid such complexity, learn the underlying principles behind the assembly of function and render the modular assembly of enzymatic function a tangible reality. A key feature of such protein design is the control and exclusion of water access to the protein core to provide the low-dielectric environment that enables enzymatic function. Recent successes in de novo protein design have illustrated how such control can be incorporated into the design process and have paved the way for the synthesis of nascent enzymatic activity in these systems.
Iron and copper, and their interactions during development
Authors: Gambling Lorraine , Andersen Henriette S. , McArdle Harry J.
Published: December 2008

During development, the fetus is entirely dependent on the mother for its nutrient requirements. Subsequently, it is a period when both are vulnerable to changes in dietary supply, especially of those nutrients that are marginal under normal circumstances. In developed countries, this applies mainly to micronutrients. Even now, iron deficiency is a common disorder, especially in pregnancy. Similarly, copper intake in the U.K. population is rarely above adequate levels. It is now becoming clear that nutrient deficiencies during pregnancy can result in problems for the offspring, in both the short- and long-term. Early studies showed that lambs born to mothers on copper-deficient pastures developed ‘swayback’, with neurological and muscular symptoms that could not be reversed by postnatal supplementation. Our own findings have shown that prenatal iron deficiency results in increased postnatal blood pressure, even though the offspring have normal dietary iron levels from birth. These observations emphasize the importance of iron and copper in growth and development. Complicating the situation further is the fact that copper and iron are known to interact with each other in many ways, including absorption and intracellular transport. However, their interactions during the pregnancy appear to be more complex than during the non-pregnant state. In the present review, we examine the importance of these metals and their interactions, the consequences, both short- and long-term, of deficiency and consider some possible mechanisms whereby these effects may be generated.
Mechanisms of mammalian zinc-regulated gene expression
Authors: Jackson Kelly A. , Valentine Ruth A. , Coneyworth Lisa J. , Mathers John C. , Ford Dianne
Published: December 2008

Mechanisms through which gene expression is regulated by zinc are central to cellular zinc homoeostasis. In this context, evidence for the involvement of zinc dyshomoeostasis in the aetiology of diseases, including Type 2 diabetes, Alzheimer's disease and cancer, highlights the importance of zinc-regulated gene expression. Mechanisms elucidated in bacteria and yeast provide examples of different possible modes of zinc-sensitive gene regulation, involving the zinc-regulated binding of transcriptional activators and repressors to gene promoter regions. A mammalian transcriptional regulatory mechanism that mediates zinc-induced transcriptional up-regulation, involving the transcription factor MTF1 (metal-response element-binding transcription factor 1), has been studied extensively. Gene responses in the opposite direction (reduced mRNA levels in response to increased zinc availability) have been observed in mammalian cells, but a specific transcriptional regulatory process responsible for such a response has yet to be identified. Examples of single zinc-sensitive transcription factors regulating gene expression in opposite directions are emerging. Although zinc-induced transcriptional repression by MTF1 is a possible explanation in some specific instances, such a mechanism cannot account for repression by zinc of all mammalian genes that show this mode of regulation, indicating the existence of as yet uncharacterized mechanisms of zinc-regulated transcription in mammalian cells. In addition, recent findings reveal a role for effects of zinc on mRNA stability in the regulation of specific zinc transporters. Our studies on the regulation of the human gene SLC30A5 (solute carrier 30A5), which codes for the zinc transporter ZnT5, have revealed that this gene provides a model system by which to study both zinc-induced transcriptional down-regulation and zinc-regulated mRNA stabilization.
Ceruloplasmin in neurodegenerative diseases
Authors: Texel Sarah J. , Xu Xueying , Harris  Z. Leah
Published: December 2008

Two decades ago, patients lacking circulating serum ceruloplasmin (Cp) presented with neurodegeneration associated with brain iron accumulation. These patients, with mutations in the MCO (multi-copper oxidase), Cp, revealed an essential role for Cp in iron homoeostasis. The patients were diagnosed in adulthood with CNS (central nervous system) disease and progressed rapidly, making understanding the mechanism of disease imperative. We now know that (i) Cp regulates the efficiency of iron efflux, (ii) Cp stabilizes ferroportin membrane expression, (iii) GPI (glycosylphosphatidylinositol)-linked Cp is the predominant form expressed in brain, (iv) Cp functions as a ferroxidase and regulates the oxidation of Fe2+ to Fe3+, (v) Cp does not bind to transferrin directly, and (vi) Cp is one member of a family of mammalian MCOs, which includes hephaestin. It is still unclear how an absence of Cp results in neurodegeneration: is the iron accumulation a primary or secondary injury? Although it is attractive to invoke an iron-mediated oxidative stress mechanism for the neuronal injury and degeneration in aceruloplasminaemia, our data suggest limited redox injury in the brains of mice lacking MCO. In fact, we propose a role for neuronal iron starvation with associated astrocyte and microglial iron overload. With the defect in aceruloplasminaemia being one of inefficient iron efflux from macrophages, we believe that the iron is trapped in a compartment not readily available to participate in oxyradical injury. It is likely that different mechanisms of neuronal cell protection are offered by astrocytes and microglia, and, once these cells are damaged, neuronal survival is compromised.
Albumin as a zinc carrier: properties of its high-affinity zinc-binding site
Authors: Lu Jin , Stewart Alan J. , Sadler Peter J. , Pinheiro Teresa J.T. , Blindauer Claudia A.
Published: December 2008

Although details of the molecular mechanisms for the uptake of the essential nutrient zinc into the bloodstream and its subsequent delivery to zinc-requiring organs and cells are poorly understood, it is clear that in vertebrates the majority of plasma zinc (9–14 μM; approx. 75–85%) is bound to serum albumin, constituting part of the so-called exchangeable pool. The binding of metal ions to serum albumins has been the subject of decades of studies, employing a multitude of techniques, but only recently has the identity and putative structure of the major zinc site on albumin been reported. Intriguingly, this site is located at the interface between two domains, and involves two residues from each of domains I and II. Comparisons of X-ray crystal structures of free and fatty-acid bound human serum albumin suggest that zinc binding to this site and fatty acid binding to one of the five major sites may be interdependent. Interactive binding of zinc and long-chain fatty acids to albumin may therefore have physiological implications.
Inner nuclear membrane protein transport is mediated by multiple mechanisms
Authors: Zuleger Nikolaj , Korfali Nadia , Schirmer Eric C.
Published: December 2008

Work in the nuclear transport field has led to an incredibly detailed description of protein translocation through the central channel of the nuclear pore complex, yet the mechanism by which nuclear envelope transmembrane proteins reach the inner nuclear membrane after synthesis in the endoplasmic reticulum is still hotly debated. Three different translocation models have gained experimental support: (i) simple lateral diffusion through the nuclear envelope membrane system; (ii) translocation by vesicle fusion events; and (iii) a variation on classical transport mediated by the nuclear pore complex. Although these models appear to be mutually exclusive, in the present paper we argue that they probably all function for different inner nuclear membrane proteins according to their unique characteristics.
Protein energy landscape roughness
Authors: Kapon Ruti , Nevo Reinat , Reich Ziv
Published: December 2008

The ‘new view’ of proteins sees protein reactions as parallel processes occurring along funnelled energy landscapes. These landscapes are generally not smooth, but are superimposed by hills and valleys of different heights and widths leading to roughness on the energy surface. In the present paper, we describe the origins of protein energy landscape roughness, measurements of its scale and its implications.
MAPPIT: a versatile tool to study cytokine receptor signalling
Authors: Lemmens Irma , Lievens Sam , Tavernier Jan
Published: December 2008

MAPPIT (mammalian protein–protein interaction trap) is a cytokine receptor-based two-hybrid method that operates in intact mammalian cells. A bait is fused C-terminally to a STAT (signal transducer and activator of transcription) recruitment-deficient receptor, whereas the prey is linked to functional STAT-binding sites. When bait and prey interact a ligand-dependent complementation of the STAT recruitment deficiency occurs, leading to activation of a STAT-responsive reporter. MAPPIT is very well suited to study protein interactions involving activated cytokine receptors as the technique allows modification of the bait protein in a physiologically optimal environment.
Mannose-binding lectin genetics: from A to Z
Authors: Garred Peter
Published: December 2008

MBL (mannose-binding lectin) is primarily a liver-derived collagen-like serum protein. It binds sugar structures on micro-organisms and on dying host cells and is one of the four known mediators that initiate activation of the complement system via the lectin pathway. Common variant alleles situated both in promoter and structural regions of the human MBL gene (MBL2) influence the stability and the serum concentration of the protein. Epidemiological studies have suggested that genetically determined variations in MBL serum concentrations influence the susceptibility to and the course of different types of infectious, autoimmune, neoplastic, metabolic and cardiovascular diseases, but this is still a subject under discussion. The fact that these genetic variations are very frequent, indicates a dual role of MBL. This overview summarizes the current molecular understanding of human MBL2 genetics.
Siglecs as positive and negative regulators of the immune system
Authors: Crocker Paul R. , Redelinghuys Pierre
Published: December 2008

Siglecs (sialic acid-binding Ig-like lectins) are mainly expressed in the immune system. Sn (sialoadhesin) (siglec-1), CD22 (siglec-2) and siglec-15 are well conserved, whereas the CD33-related siglecs are undergoing rapid evolution, as reflected in large differences in repertoires among the different mammals studied so far. In the present paper, we review recent findings on the signalling properties of the CD33-related siglecs and discuss the emergence of both inhibitory and activating forms of this family. We also discuss how Sn may function as a positive regulator of adaptive immune responses and its emerging role as an induced macrophage pattern-recognition molecule for sialylated pathogens, especially enveloped viruses.
Galectin–glycan lattices regulate cell-surface glycoprotein organization and signalling
Authors: Garner Omai B. , Baum Linda G.
Published: December 2008

The formation of multivalent complexes of soluble galectins with glycoprotein receptors on the plasma membrane helps to organize glycoprotein assemblies on the surface of the cell. In some cell types, this formation of galectin–glycan lattices or scaffolds is critical for organizing plasma membrane domains, such as lipid rafts, or for targeted delivery of glycoproteins to the apical or basolateral surface. Galectin–glycan lattice formation is also involved in regulating the signalling threshold of some cell-surface glycoproteins, including T-cell receptors and growth factor receptors. Finally, galectin–glycan lattices can determine receptor residency time by inhibiting endocytosis of glycoprotein receptors from the cell surface, thus modulating the magnitude or duration of signalling from the cell surface. This paper reviews recent evidence in vitro and in vivo for critical physiological and cellular functions that are regulated by galectin–glycoprotein interactions.
Lectin–epithelial interactions in the human colon
Authors: Rhodes Jonathan M. , Campbell Barry J. , Yu Lu-Gang
Published: December 2008

Similar changes in glycosylation occur in the colonic epithelium in inflammatory conditions such as ulcerative colitis and Crohn's disease and also in colon cancer and precancerous adenomatous polyps. They include reduced length of O-glycans, reduced sulfation, increased sialylation and increased expression of oncofetal carbohydrate antigens, such as sialyl-Tn (sialylα2-6GalNAc), and the TF antigen (Thomsen–Friedenreich antigen) Galβ1-3GalNAcα-Ser/Thr. The changes affect cell surface as well as secreted glycoproteins and mediate altered interactions between the epithelium and lectins of dietary, microbial or human origin. Different TF-binding lectins cause diverse effects on epithelial cells, reflecting subtle differences in binding specificities e.g. for sialylated TF; some of these interactions, such as with the TF-binding peanut lectin that resists digestion, may be biologically significant. Increased TF expression by cancer cells also allows interaction with the human galactose-binding lectin, galectin-3. This lectin has increased concentration in the sera of patients with metastatic cancer and binds TF on cancer cell surface MUC1 (mucin 1), causing clustering of MUC1 and revealing underlying adhesion molecules which promote adhesion to endothelium. This is likely to be an important mechanism in cancer metastasis and represents a valid therapeutic target. Tools are now available to allow fast and accurate elucidation of glycosylation changes in epithelial disease, characterization of their potential lectin ligands, whether dietary, microbial or human, and determination of the functional significance of their interactions. This should prove a very fruitful area for future research with relevance to infectious, inflammatory and cancerous diseases of the epithelia.
Systemic hypoxia enhances bactericidal activities of human polymorphonuclear leuocytes
Authors: Wang Jong-Shyan , Liu Huang-Chun
Published: December 2008

ROS (reactive oxygen species) generated by hypoxia facilitate the vascular inflammatory response, but whether systemic hypoxia influences leucocyte bactericidal activity by modulating circulatory redox status remains unclear. The present study elucidates how various hypoxic interventions influence the bactericidal activity of PMNs (polymorphonuclear leucocytes) following treatment with an antioxidant, vitamin E (D-α-tocopheryl acetate). Forty healthy sedentary men were randomly assigned to vitamin E (n=20) and placebo (n=20) groups. At 1 h following oral administration of 1000 i.u. of vitamin E or placebo, each subject in the two groups was randomly exposed to 12%, 15%, 18% and 21% O2 for 2 h in a normobaric hypoxia chamber. The results demonstrated that exposure to 12% O2 in the placebo group increased urinary 8-isoprostane and plasma malondialdehyde levels and decreased plasma total antioxidant content and superoxide dismutase activity, but did not alter plasma complement-C3a desArg/C4a desArg/C5a concentrations. Moreover, this hypoxic exposure also increased the chemotaxis of PMNs by exposure to N-formyl-Met-Leu-Phe, the phagocytosis of PMNs to Escherichia coli and the release of PMN oxidant products by E. coli, processes which were accompanied by increased expressions of L-selectin, LFA-1 (lymphocyte function-associated antigen 1), Mac-1, FcγIIIBR, C1qRp and C5aR on PMNs. However, exposure to 12% O2 in the vitamin E group did not influence expression of the opsonic/complement receptors on PMNs, and the chemotactic, phagocytic or oxidative burst activities of PMN, whereas the circulatory redox status and complement fragment levels were unaltered following this hypoxic exposure and pretreatment with vitamin E. Additionally, the circulatory redox status, complement systems, PMN-mediated bactericidal processes and the opsonic/complement receptors on PMNs were constant following exposure to 15%, 18% or 21% O2 in the two groups. We conclude that exposure to 12% O2 promotes the chemotactic, phagocytic and oxidative burst activities of PMNs, possibly by increasing lipid peroxidation and decreasing antioxidative capacity. However, this hypoxic effect on PMN bactericidal activity is ameliorated by pretreatment with vitamin E.
The interaction between multioverlaps in the high temperature phase of the Sherrington–Kirkpatrick spin glass
Authors: Crawford Nicholas
Published: December 2008

In this paper we explore the joint behavior of a finite number of multioverlaps in the high temperature phase of the Sherrington–Kirkpatrick model. Extending the work by Talagrand [Spin Glasses: A Challenge for Mathematicians. Cavity and Mean Field Models, A series of Modern Surveys in Mathematics Vol. 46 (Springer-Verlag, Berlin, 2003)], we show that, when these objects are scaled to have nontrivial limiting distributions, the joint behavior is described by a Gaussian process with an explicit covariance structure.
Experimental study of an active grid-generated shearless mixing layer and comparisons with large-eddy simulation
Authors: Kang Hyung Suk , Meneveau Charles
Published: December 2008

A shearless mixing layer characterized by interactions between two regions with different turbulence intensities but without mean shear is investigated experimentally in a wind tunnel. Reynolds numbers higher than those of prior studies [B. Gilbert, “Diffusion mixing in grid turbulence without mean shear,” J. Fluid Mech. 100, 349 (1980); S. Veeravalli and Z. Warhaft, “The shearless turbulent mixing layer,” J. Fluid Mech. 207, 191 (1989); B. Knaepen, O. Debliquy, and D. Carati, “Direct numerical simulation and large-eddy simulation of a shear-free mixing layer,” J. Fluid Mech. 514, 153 (2004); D. Tordella and M. Iovieno, “Numerical experiments on the intermediate asymptotics of shear-free turbulent transport and diffusion,” J. Fluid Mech. 549, 429 (2006); D. A. Briggs, J. H. Ferziger, J. R. Koseff, and S. G. Monismith, “Entrainment in a shear-free turbulent mixing layer,” J. Fluid Mech. 310, 215 (1996)] are achieved by using an active grid with rotating winglets on one-half of its cross section. Stationary flow-conditioning fine meshes are used to avoid mean velocity gradients. Measurements are performed at five different downstream wind-tunnel locations using an X-type hot-wire probe and a stereoscopic particle image velocimetry system. The Reynolds numbers based on the Taylor microscale in the high- and low-kinetic energy regions are 170 and 88, respectively. The energy and integral length-scale ratios between the two regions are 4.27 and 1.73, respectively. The inlet turbulence in the upper and lower portions of the shearless mixing layer is not fully isotropic, with the streamwise velocity fluctuations being between 6% and 13% higher than the cross-stream ones. Fundamental statistical properties of the flow are documented and analyzed at various scales using band-pass box-filtered velocities. Downstream evolution of variance and half-width of the mixing layer, skewness and flatness factors, as well as the statistics of two-point velocity increments at various displacements are presented. It is found that much of the deviations from Gaussian statistics originate from large-scale motions. The data are well suited to be used as initial condition for simulations and as test for large-eddy simulation (LES) models and codes. Comparison studies for three LES models including Smagorinsky, dynamic Smagorinsky, and dynamic mixed nonlinear models are implemented in simulations of temporally decaying shearless mixing layer using a pseudospectral code. Initial conditions are prescribed by matching the longitudinal energy spectra at all heights across the layer for both streamwise and cross-stream velocity components. LES with all three subgrid scale models tested underpredicts the kinetic energy and exhibits deviations from the measured non-Gaussian behaviors. Overall, the dynamic Smagorinsky model predicts statistics slightly better than the other two models.
Localized orbital corrections applied to thermochemical errors in density functional theory: The role of basis set and application to molecular reactions
Authors: Goldfeld Dahlia A. , Bochevarov Arteum D. , Friesner Richard A.
Published: December 2008

This paper is a logical continuation of the 22 parameter, localized orbital correction (LOC) methodology that we developed in previous papers [R. A. Friesner et al., J. Chem. Phys. 125, 124107 (2006); E. H. Knoll and R. A. Friesner, J. Phys. Chem. B 110, 18787 (2006).] This methodology allows one to redress systematic density functional theory (DFT) errors, rooted in DFT’s inherent inability to accurately describe nondynamical correlation. Variants of the LOC scheme, in conjunction with B3LYP (denoted as B3LYP-LOC), were previously applied to enthalpies of formation, ionization potentials, and electron affinities and showed impressive reduction in the errors. In this paper, we demonstrate for the first time that the B3LYP-LOC scheme is robust across different basis sets [6-31G∗, 6-311++G(3df,3pd), cc-pVTZ, and aug-cc-pVTZ] and reaction types (atomization reactions and molecular reactions). For example, for a test set of 70 molecular reactions, the LOC scheme reduces their mean unsigned error from 4.7 kcal/mol [obtained with B3LYP/6-311++G(3df,3pd)] to 0.8 kcal/mol. We also verified whether the LOC methodology would be equally successful if applied to the promising M05-2X functional. We conclude that although M05-2X produces better reaction enthalpies than B3LYP, the LOC scheme does not combine nearly as successfully with M05-2X than with B3LYP. A brief analysis of another functional, M06-2X, reveals that it is more accurate than M05-2X but its combination with LOC still cannot compete in accuracy with B3LYP-LOC. Indeed, B3LYP-LOC remains the best method of computing reaction enthalpies.
Heating of metallic powders by microwaves: Experiment and theory
Authors: Buchelnikov V. D. , Louzguine-Luzgin D. V. , Xie G. , Li S. , Yoshikawa N. , Sato M. , Anzulevich A. P. , Bychkov I. V. , Inoue A.
Published: December 2008

It is known that bulk metallic samples reflect microwaves while powdered samples can absorb such radiation and be heated efficiently. In the present work we studied heating mechanisms of metallic powders in a multimode 2.45 GHz microwave applicator. The present paper shows direct evidence of penetration of a layer of metallic powder by microwave radiation and provides theoretical explanation of such behavior.The most effectively heated powder is Fe because both eddy current loss (in alternating H-field) and magnetic reversal loss (in alternating E-field) mechanisms act in case of such metal. Diamagnetic metals Sn and Cu are heated better than paramagnetic Ti while Au is also only slightly heated. Cu- and Ni-based metallic glassy powders are also moderately heated. Weak heating of Au powder (which is a noble metal) can be explained by the absence on the particles of the oxide layer (shell), which allows eddy currents flowing through larger area compared to other metals, and reflection mechanism works much better in such case.
The influence of the top-contact metal on the ferroelectric properties of epitaxial ferroelectric Pb(Zr0.2Ti0.8)O3 thin films
Authors: Pintilie Lucian , Vrejoiu Ionela , Hesse Dietrich , Alexe Marin
Published: December 2008

Electrical properties, i.e., dielectric hysteresis and leakage current, of epitaxial Pb(Zr0.2Ti0.8)O3 films with bottom SrRuO3 electrode and different metals as top contact were investigated. The leakage current is largely insensitive to the work function of the top metal but increases with decreasing electronegativity as well as with decreasing number of electrons on the d-shell of the top metal. The best rectifying properties are obtained for metals with complete d-shell (Cu, Au, Ag, Pd), while the metals with few electrons on the d-shell (Ta, Cr) form Ohmic-like contacts.
A furnace to 1200 K for in situ heating x-ray diffraction, small angle x-ray scattering, and x-ray absorption fine structure experiments
Authors: Cai Quan , Wang Qiang , Wang Wei , Mo Guang , Zhang Kunhao , Cheng Weidong , Xing Xueqing , Chen Zhongjun , Wu Zhonghua
Published: December 2008

A furnace with a water-cooled outside shell has been assembled to do in situ x-ray diffraction (XRD), small angle x-ray scattering (SAXS), and x-ray absorption fine structure (XAFS) experiments. The details of the furnace are described in this paper. The in situ XRD, SAXS, and XAFS experiments during the heating process demonstrate that the available temperature range of this furnace is from room temperature to 1200 K with a temperature accuracy of ±0.1 K. By using this furnace, in situ XRD, SAXS, and XAFS experimental techniques with temperature change can be easily combined together.
A tight-binding potential for helium in carbon systems
Authors: Granot Rebecca , Baer Roi
Published: December 2008

The presence of helium in carbon systems, such as diamonds and fullerenes is of interest for planetary sciences, geophysics, astrophysics, and evolution biology. Such systems typically involve a large number of atoms and require a fast method for assessing the interaction potential and forces. We developed a tight-binding approach, based on density functional calculations, which includes a many-body potential term. This latter term is essential for consolidating the density functional results of helium in bulky diamond and Helium passing through a benzene ring which is important for helium-fullerene applications. The method is simple to apply and exhibits good transferability properties.
Impact of carrier localization on the photoluminescence characteristics of (Ga,In)(N,As) and (Ga,In)(N,As,Sb) quantum wells
Authors: Ishikawa Fumitaro , Guzmán Álvaro , Brandt Oliver , Trampert Achim , Ploog Klaus H.
Published: December 2008

Using photoluminescence (PL) spectroscopy, we carry out a comparative study of the optical properties of (Ga,In)(N,As) and (Ga,In)(N,As,Sb) quantum wells. The incorporation of Sb into (Ga,In)(N,As) results in a reduced quantum efficiency at low temperatures but an improved one at room temperature (RT). A PL line shape analysis as well as the temperature dependence of the PL peak energy reveals the existence of band-tail localized states in both material systems. The carrier localization energy is larger for (Ga,In)(N,As,Sb) than for (Ga,In)(N,As), leading to a longer radiative lifetime and thus a reduced quantum efficiency at low temperatures for the former material. The thermal quenching of the quantum efficiency is analyzed by a rate equation model, which shows that the density of nonradiative centers is reduced in (Ga,In)(N,As,Sb) resulting in an enhanced quantum efficiency at RT.
Epitaxial growth of nickel on Si(100) by dc magnetron sputtering
Authors: Kreuzpaintner W. , Störmer M. , Lott D. , Solina D. , Schreyer A.
Published: December 2008

The influence of the substrate temperature on the growth of highly textured Ni(111) and epitaxial Ni(200) with the relationships Ni[100]∥Si[110] and Ni(001)∥Si(001) on hydrogen terminated Si(100) wafer substrates by means of direct current magnetron sputtering is reported. In order to minimize crystal defect formation and to achieve a high quality epitaxial growth of Ni on Si, a two step deposition process was developed whereby different deposition conditions were used for an initial nickel seed layer and the remaining nickel film. The in-plane and out-of-plane structural properties of the films were investigated using x-ray scattering techniques, whereas magneto-optical Kerr effect and neutron reflectometry were used to confirm the magnetic nature of the epitaxially deposited nickel films.
Impact of Cu contamination on the electrical properties of a direct silicon bonded (110)/(100) interfacial grain boundary
Authors: Yu Xuegong , Lu Jinggang , Rozgonyi George
Published: December 2008

Cu contamination of a “model” grain boundary (GB) created by direct silicon bonding of (110)/(100) wafers has been investigated by monitoring the hole emission from GB states. It is found that the electronic states at the clean GB are localized, whereas following Cu contamination, they transform into bandlike states with much larger hole capture cross sections. Following an increase in Cu contamination at the GB by a quenching anneal, the density of GB states decreases, while the GB neutral level remains constant, essentially independent of contamination temperature. It is believed that the electrically active Cu-related states present at the GB are generated from the surfaces of localized Cu precipitates, whereas quench cooling from a higher contamination temperature produces a lower density of large precipitates which results in a reduced density of Cu-related GB states.
Ferroelectric and non-linear dielectric characteristics of Bi0.5Na0.5TiO3 thin films deposited via a metallorganic decomposition process
Authors: Xu Jinbao , Liu Yun , Withers Ray L. , Brink Frank , Yang Hui , Wang Mark
Published: December 2008

Polycrystalline Bi0.5Na0.5TiO3 (NBT) thin films have been successfully fabricated via a metal organic decomposition process on Pt/Ti/SiO2/Si substrates. The structural evolution of the as-prepared thin films annealed over the moderate temperature range 500–700 °C is studied. NBT thin films annealed at 700 °C are of single phase NBT perovskite type. They exhibit a well-defined P-E hysteresis loop at room temperature. The measured dielectric constant is 465–410 over the frequency range of 1 kHz to 1 MHz. The corresponding dielectric loss is ∼10−2. The measured capacitance-voltage curve shows strong non-linear dielectric behavior leading to a high tunability of the dielectric constant, up to 14% at 1 MHz.
B
2
structure of high-entropy alloys with addition of Al
Authors: Li C. , Zhao M. , Li J. C. , Jiang Q.
Published: December 2008

A series of AlCrCoNiFe based alloys with equal percentage of principal components (high-entropy alloys or HE alloys) is fabricated. The related crystalline structures of the alloys are measured and calculated. Results show that the formed bcc phase is a compound based B2 structure where there is partial ionic bonding between Al and other transition metals. Thus, the bcc structure of the alloys should be a B2 instead of an A2 due to the large difference in electronegativities among the components consisting of the HE alloys.
White light upconversion emissions from Tm3++Ho3++Yb3+ codoped tellurite and germanate glasses on excitation with 798 nm radiation
Authors: Giri Neeraj Kumar , Rai D. K. , Rai S. B.
Published: December 2008

White light has been produced using 798 nm laser excitation in Tm3++Ho3++Yb3+ codoped tellurite and germanate glasses. These glasses simultaneously generate the three primary colors, red, green, and blue, on 798 nm excitation. Thus, multicolor emission obtained was tuned to white luminescence by adjusting the Ho3+ ion concentration and excitation power. UV excitation and fluorescence spectra of these triply doped glasses give additional emissions, which do not appear on 798 nm excitation.
Molecular dynamics simulations of buckling-induced plasticity
Authors: Durinck Julien , Coupeau Christophe , Colin Jérôme , Grilhé Jean
Published: December 2008

Molecular dynamics simulations of thin film buckling demonstrate that high compressive stresses are localized in the straight-sided wrinkle leading to the nucleation of dislocations, which are mobile and plastically release a large amount of the strain. As a consequence, the maximum deflection determined in the framework of elasticity theory is found to be overestimated. Finally, the resulting plastic deformation has been estimated and included in the expression of the deflection.
Electrical and structural properties of BaCe0.90Y0.10O3−δ thin film on MgO (100) substrate
Authors: Hosono Hiroyo , Higuchi Tohru , Hattori Takeshi
Published: December 2008

Y-doped BaCeO3 (BaCe0.90Y0.10O3−δ) thin films have been deposited on (100) MgO substrates by pulsed laser deposition. The BaCe0.90Y0.10O3−δ thin film prepared at substrate temperature of 600 °C and oxygen gas pressure of 15 mTorr exhibits a predominantly c-axis orientation. The thin film consists of small grains with a diameter of 50 nm and smooth surface. The electrical conductivity of the thin film exhibits thermal activation type behavior. The conductivity in H2O atmosphere is higher than that in D2O atmosphere in the temperature range from 700 to 350 °C. The ratio of σ(H2O) and σ(D2O) is approximately 1.4, which is close to the square root of the mass ratio of the proton to deuteron. These results indicate the existence of proton conduction in BaCe0.90Y0.10O3−δ thin film. The activation energy (EA) of the thin film estimated from the Arrhenius plot is 0.92 eV, which is nearly equal to the energy separation between the top of valence band and Fermi level, although the EA value of thin film is higher than that of the bulk.
Cavity-dumped 2.70 μm erbium laser using optomechanical shutter
Authors: Park Young Ho , Won Lee Dong , Kong Hong Jin , Kim Yeong Sik
Published: December 2008

A cavity-dumped 2.70 μm erbium laser with a frustrated total internal reflection (FTIR) shutter was investigated and compared with a Q-switched erbium laser using the FTIR shutter. The Q-switched and the cavity-dumped 2.70 μm laser outputs were obtained with a dichroic coated mirror with high reflectance at 2.70 μm and high transmittance at 2.79 μm. For the Q-switched operation, a maximum peak power of 33.5 kW was achieved, and its pulse width was 1.3 μs. For the cavity-dumped operation, the laser pulse energy was optimized by changing the switching time of the FTIR shutter. When the pulse width is reduced to 210 ns, the peak power increases to 154 kW.
Effect of quantity and configuration of attached bacteria on bacterial propulsion of microbeads
Authors: Behkam Bahareh , Sitti Metin
Published: December 2008

Flagellated chemotactic bacteria have been utilized as actuators for propulsion of polystyrene microbeads by randomly attaching several bacteria on their surface. In this work, a plasma-based bacteria patterning technique is developed and used to limit bacteria attachment to approximately half of the microbead’s surface. Consequently, the effect of quantity and configuration of the attached bacteria on propulsion speed is studied experimentally. It is shown that the correlation between the propulsion speed and the number of bacteria is a strong function of the configuration of the bacteria and it follows one of the two distinct trends quantified by the proposed stochastic model.
On Geography and Materiality
Authors: Anderson Ben , Wylie John
Published: December 2008

In the context of human geography's encounter with the problematics that surround matter and materiality, this paper offers a principle that works towards a distinctive material imagination. This principle states that our image of matter should be multiplied, so that it can be attended to as taking place with the properties and capacities of any element or state. We elaborate this principle through three substantive discussions of materiality as turbulent, as interrogative, and as excessive. In doing so we draw upon, in turn, forms of relational materialism associated with actor-network theory, the postphenomenologies of Lingis, the animate or enchanted materialism developed by Bennett, and the figurative and affective (im)materialities of Deleuze. The conclusion clarifies why we do not call for geography to be ‘rematerialised’.
Urban Population Loss in Historical Perspective: United States, 1820–2000
Authors: Beauregard Robert A
Published: December 2008

Employing an historical perspective, the author mounts a quantitative and theoretical assessment of population loss in the large cities of the United States. Three periods are considered: one prior to 1920 when large city population loss was aberrant; a second which captures the severe decline of the decades after World War II, and a third that encompasses the more recent shrinkage of cities. Population loss is measured in terms of prevalence, severity, and persistence and is also analyzed geographically. The author further identifies factors affecting population loss which are common and unique to each period. Although population loss has diminished, a number of cities are locked into trajectories of chronic loss, suggesting that a new phase of urbanization has yet to materialize.
Fixed Minerals, Scalar Politics: The Weight of Scale in Conflicts over the ‘1872 Mining Law’ in the United States
Authors: Huber Matthew T , Emel Jody
Published: December 2008

In this paper, we seek to demonstrate the continued utility of research into the social production of scale in relation to the politics of natural-resource distribution, ownership, and control. While traditionally oriented toward sociospatial theory and urban governance, research has begun to convey the importance of scale as a discursive framing device at the center of multiple kinds of environmental politics. Our approach draws from recent literature to show the material-discursive ‘difference that nature makes’ in constituting the grounds of scalar struggle in mineral development. We argue that the fixity of certain natural-resource deposits and the concomitant local socioecological impact of extraction stands in stark contradiction to the multiscalar forces that vie over their development. Our central argument is that this contradiction ensures that struggles over natural-resource development are necessarily struggles over scale—the scale of ownership and the scale of distributional benefits and costs. The politics of natural resources must be couched in scalar terms and those who gain access to resources must build stable institutional–scalar platforms for the production of resource wealth. We illustrate this through an analysis of US Congressional debate over reform of the infamous ‘1872 Mining Law’ in 1993 as an exemplary moment of scalar politics. In this case, we not only attempt to show how the concept of scale frames these debates, but also how the failure to reform the 19th-century law allowed for the institutional materialization of particular scalar conduits for capital accumulation in the mining sector.
A Multistate Model for Projecting Regional Populations by Indigenous Status: An Application to the Northern Territory, Australia
Authors: Wilson Tom
Published: December 2008

The author presents a multistate model for projecting regional populations by Indigenous status. Previous methods employed to project the Australian Indigenous population did not model interaction between the Indigenous and non-Indigenous populations, in large part because of serious data deficiencies. Improvements in data coverage and quality, particularly in the Northern Territory, now permit the effective use of conceptually preferable multistate methods. The multistate model presented in this paper explicitly incorporates identification change and, in contrast to previous modelling which has assumed all offspring of mixed Indigenous/non-Indigenous couples to be Indigenous, permits babies born to mixed couples to be ascribed either Indigenous or non-Indigenous identities. A hybrid directional–net-migration approach is taken to the modelling of internal migration. Illustrative projections are presented for the Northern Territory.
Manufacturing Space: Gendered Cityscapes and Industrial Images in Dundee
Authors: Wainwright Emma
Published: December 2008

Recent interest in the material and discursive construction of built environments has largely focused on the iconic skyscraper as a symbol of ‘modern’ global and corporate power. Within this theoretical frame, industrial landscapes are given short shrift. I seek to redress this by taking the example of Victorian and Edwardian Dundee and exploring the construction of a specific manufacturing space by the city's industrial elite. Moreover, this paper moves beyond traditional analyses to take a specifically gendered look at this process. I argue that, while women numerically dominated Dundee's jute industry, it was men as jute-company directors who laid claim to place through their role in image making. The paper starts by looking at the processes of building and elaborating industrial space and power through an investigation of the fabric of the city. It then explores how such materiality was accompanied by and represented in a range of industrial imagery. Unpacking this landscape—pointing to the construction and subversion of gendered binaries and the recursive relationship between the material and immaterial—helps us see how industrial elites fashioned and reaffirmed their identity and power through the mobilisation of a set of representational tactics, creating a particularly gendered manufacturing (of) space.
Regional Variations in Voting at British General Elections, 1950–2001: Group-Based Latent Trajectory Analysis
Authors: Johnston Ron , Jones Kelvyn , Jen Min-Hua
Published: December 2008

Little work has been done on long-term trends in support for British political parties because of the absence of comparable data over more than four elections. Using a dataset of estimated vote percentages for each party over fifteen elections for a constant set of 641 ‘pseudo-constituencies' (based on those used for the 1997 and 2001 general elections) this paper uses a recently developed inductive procedure for identifying spatially varying temporal trends to identify variations in party support since 1950, enabling hypotheses regarding their nature to be formally tested. Whereas varying trends in Conservative support were predominantly regional—supporting the concept of a north–south divide—there was greater variation by functional type than geographical region in the patterning of support trends for the other two parties.