bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for monoclinic crystal structure and negative thermal expansion below magnetic transition temperature in Pb(Fe1∕2Nb1∕2)O3
Authors: Singh Satendra Pal , Pandey Dhananjai , Yoon Songhak , Baik Sunggi , Shin Namsoo
Published: June 2007

The existing controversy about the room temperature structure of multiferroic Pb(Fe1∕2Nb1∕2)O3 is settled using synchrotron powder x-ray diffraction data. Results of Rietveld refinements in the temperature range of 300–12K reveal that the structure remains monoclinic in the Cm space group down to 12K, but the lattice parameters show anomalies at the magnetic transition temperature (TN) due to spin-lattice coupling. The lattice volume exhibits negative thermal expansion behavior, with α=−4.64×10−6K−1, below TN.
Epitaxy and recrystallization kinetics of TaC thin films on SiC for high temperature processing of semiconductor devices
Authors: Vispute R. D. , Hullavarad S. , Luykx A. , Young D. , Dhar S. , Venkatesan T. , Jones K. A. , Zheleva T. S. , Ervin M. , Derenge M.
Published: June 2007

The authors report the epitaxial growth of cubic TaC thin films on 4H-SiC (0001) substrates by pulsed laser deposition and their recrystallization kinetics. The growth temperature for epitaxy was found to be 1000°C. The activation energy for the recrystallization was 1.5eV. High temperature annealing produced changes in the surface morphology which caused grain growth and created pinholes through a recrystallization process in the films deposited at lower temperatures. The films deposited at higher temperatures remained virtually unchanged. Implications of these results are discussed in the context of the development of future high temperature and high-power electronic devices.
Freestanding waveguides in silicon
Authors: Yang P. Y. , Mashanovich G. Z. , Gomez-Morilla I. , Headley W. R. , Reed G. T. , Teo E. J. , Blackwood D. J. , Breese M. B. H. , Bettiol A. A.
Published: June 2007

Using a direct-write process for the production of three dimensional microstructures on a semiconductor, freestanding waveguides have been realized in silicon. The waveguides are produced by a focused beam of high energy protons that is scanned over a silicon substrate. The latent image of the scan is subsequently developed by electrochemical etching. Herein the authors report on the fabrication method as well as determining the propagation loss of these structures. Propagation loss values of 13.4 and 14.6dB∕cm were obtained for these preliminary structures for transverse electric and transverse magnetic polarizations, respectively.
Simulation of the flow induced by acoustic streaming in noncontact ultrasonic motors
Authors: Cheng L. P. , Zhang S. Y.
Published: June 2007

In order to overcome many shortcomings of the traditional contact-type rotors, noncontact ultrasonic motors, which are driven by acoustic streaming, have been proposed. Recently, an analytical solution based on the second order approximation has been presented, but it gives a revolution speed five times smaller than the experimental value. In order to reconcile the discrepancy, the authors perform numerical simulations of the gas motion between the stator and the rotor driven by the acoustic streaming. With the same parameters used in the experiment, it is found that the acoustic streaming can account for the observed fast rotation.
Structure and magnetic properties of bulk nanocrystalline SmCo6.6Nb0.4 permanent magnets
Authors: Yue M. , Zhang J. X. , Zhang D. T. , Pan L. J. , Liu X. B. , Altounian Z.
Published: June 2007

The crystal structure and magnetic properties were studied for the bulk nanostructural permanent magnet SmCo6.6Nb0.4 prepared by spark plasma sintering method. The magnet crystallizes in a single phase with a hexagonal TbCu7-type crystal structure after the sintering process. Rietveld fitting results show that the alloying element of Nb prefers to occupy the 3g site. Microstructure observation indicates that the average crystal grain size is about 30nm. The coercivity decreases almost linearly from 2.8to0.5T with increasing temperature from 300to773K. A remanence enhancement resulting from intergrain exchange coupling among the fine grains was also observed.
Statistical method for thickness measurement of amorphous objects
Authors: Van Dyck D. , Croitoru M. D.
Published: June 2007

The authors propose a nondestructive method for the determination of the thickness of an amorphous sample. This method is based on the statistics of the phase of the electron exit wave function, which depend on the number of atoms traversed by the incident electron which itself is a function of the thickness of the object. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential.
Solid phase epitaxy versus random nucleation and growth in sub-20nm wide fin field-effect transistors
Authors: Duffy R. , Van Dal M. J. H. , Pawlak B. J. , Kaiser M. , Weemaes R. G. R. , Degroote B. , Kunnen E. , Altamirano E.
Published: June 2007

The authors investigate the implications of amorphizing ion implants on the crystalline integrity of sub-20nm wide fin field-effect transistors (FinFETs). Recrystallization of thin body silicon is not as straightforward as that of bulk silicon because the regrowth direction may be parallel to the silicon surface rather than terminating at it. In sub-20nm wide FinFETs surface proximity suppresses crystal regrowth and promotes the formation of twin boundary defects in the implanted regions. In the case of a 50nm amorphization depth, random nucleation and growth leads to polycrystalline silicon formation in the top ∼25nm of the fin, despite being only ∼25nm from the crystalline silicon seed.
Atom interferometer detects the birth and death of single photons without destroying them
Authors: Day Charles
Published: June 2007

Since the 1980s physicists have used photons to track quantum jumps in single atoms. Now they can use atoms to track quantum jumps of light.
Interface between nonmagnetic insulators may be ferromagnetic and conducting
Authors: Levi Barbara Goss
Published: June 2007

A ferromagnetic metal would be perhaps the first of many novel electronic states that might emerge from the marriage of complex oxides.
Astronomy outreach used for social good
Authors: Feder Toni
Published: June 2007

An astronomy project harnesses existing initiatives to reach out to young children around the world.
Helium shortage hampers research and industry
Authors: Kaplan Karen H.
Published: June 2007

If new sources of helium aren’t developed, the world’s supply of the gas will dwindle and prices will soar.
Rumor mills spread word on who’s hot and who’s hiring
Authors: Feder Toni
Published: June 2007

It’s no coincidence that the online jobs rumor mills were started by postdocs. But many faculty members also use them—to check how job seekers are faring and to gauge the research directions of other institutions.
Patterned nanomagnets
Authors: Chien C. L. , Zhu Frank Q. , Zhu Jian-Gang
Published: June 2007

The behavior of magnets with submicron dimensions depends intimately on the magnets’ shape and size. The rich variety of resulting phenomena brings with it the promise of new technologies.
Eisenhower, scientists, and Sputnik
Authors: Rigden John S.
Published: June 2007

The Soviet launch of Sputnik shook the confidence of Americans in the country’s defense and in its science. President Eisenhower convened a meeting of scientists in the Oval Office that Hans Bethe called an “unforgettable hour.”
Environmental Irony: Summoning Death in Bangladesh
Authors: Atkins Peter , Hassan Manzurul , Dunn Christine
Published: June 2007

The arsenic crisis that affects at least thirty million water consumers in Bangladesh has been called the world's greatest ever environmental health disaster. Although the problem and the potential solutions have been presented confidently in the media, the argument of this paper is that, ironically, very little of the science or the technology is certain. From the spatial and depth variabilities of contamination, through safety thresholds, to the accuracy of field testing kits, we find indeterminacy. We argue that rather than shying away from such uncertainty, however, mitigation policies must acknowledge and embrace it if any real progress is to be made.
Outliers and Spatial Dependence in Cross-Sectional Regressions
Authors: Mur Jesús , Lauridsen Jørgen
Published: June 2007

Outliers are a risk factor in any econometric analysis. They are often observations that exert an excessive influence on the results and lower our confidence in the estimations. As a consequence, the attention given to their identification and treatment in the context of time series is not surprising. Our intention in the present paper is to advance in this same direction but now focusing the discussion on the impact of outliers on cross-sectional specifications. In particular, we will analyse the behaviour of the most habitual misspecification tests in this field in the presence of outliers. With this objective, we present a series of analytical results that try to delimit the effects suffered by these statistics and complete the study with a Monte Carlo exercise designed to measure their effect more precisely. According to our results, the impact of outliers can be very important, especially when several coincide in the sample.
Querying Cosmopolis at the Borders of Europe
Authors: Kramsch Olivier Thomas
Published: June 2007

Notions of immanence provide the implicit theoretical grammar for much work exploring the political terrain of an active transnational or radically cosmopolitan society in our day. In this paper I attempt to problematize such a gesture in the recent ‘turn to cosmopolis’, arguing that its conceptual frame fails to specify adequately the geohistorical preconditions for a politics capable of mediating between nationalizing and cosmopolitanizing tendencies at work in a globalizing world. For the case of Europe, I argue such a legacy may be more productively located in the ‘border work’ of mid-20th-century anti-imperialism and decolonization, whose struggles to redefine the postcolonial couplet of ‘nation’ and ‘state’ haunt current attempts by the European Union to craft a more inclusive and cosmopolitan transboundary future. I explore how such governmentalizing phantasms specifically inform attempts to create viable cross-border regions ( euregios) within the EU, and continue to gnaw at attempts to negotiate boundary disputes at the outer limits of the continent. In conclusion, a cautious rite of exorcism is ventured by engaging with the elusive anti-imperial cosmopolitanism of Frantz Fanon.
A SWOT Analysis of Planning Support Systems
Authors: Vonk Guido , Geertman Stan , Schot Paul
Published: June 2007

Insight into the strengths, weaknesses, opportunities, and threats (SWOT) of planning support systems (PSS) is fragmented between users and system developers. The lack of combined insights blocks development in the right direction and makes potential users hesitant to apply PSS in planning. This study presents SWOT of PSS from a combined user–developer perspective. We first express them in terms of combinations of planning task, PSS information function, and user, and subsequently use a literature survey, a series of interviews, and a web survey to gather views from developers, users, and PSS experts. The analysis shows that planners mainly use simple information storage and retrieval systems for exploration tasks, while the majority of PSS are technically much more advanced and aim to support complex tasks. The potential of these advanced PSS can only be realized if planners and system developers start to share knowledge and demands and identify opportunities in a cooperative PSS-development process. Without such a process, the advantages and opportunities of PSS will remain unexploited.
Political Parties and the City: Some Thoughts on the Low Profile of Partisan Organisations and Mobilisation in Urban Political Theory
Authors: Low Murray
Published: June 2007

The author considers the strange absence of political parties in urban political theory. Having set out the problem, the author proceeds through a set of hypotheses concerning why parties are such elusive characters on the urban-studies stage. These involve, in turn: the characteristics of the literature on parties; the treatment of ‘change’ as a theme in human geography and urban studies; the effects of the dominance of the United States in the theoretical literature on urban politics; the characterisation of political ‘actors’ in this literature; and related issues surrounding the challenges which parties pose to research at a normative–democratic level. In the process it is cautiously suggested that parties be reinserted as forming part of an array of urban collective forms which repay attention in accounting for urban political transformation and, of course, inertia. The usefulness of parties as a space within which to think through problems of agency and democracy in the city and beyond, is also emphasised.
Representative Cosmopolitanism: Representing the World within Political Collectives
Authors: Zierhofer Wolfgang
Published: June 2007

Nation-states chop up the modern political sphere into autonomous (sovereign) communities. A vast literature questions the adequacy of this territorial, container-based order in the face of increasingly global patterns of interaction. A remedy is sought in a cosmopolitanization of the political sphere, above all by establishing institutions and by strengthening forms of governance on the international or supranational level. This paper develops an alternative and complementary conception of cosmopolitanization, which stresses the representation of the external world within political institutions. Representative cosmopolitanism is a conception which offers a nonterritorially garbled political representation on a global scale in spite of the territorial organization of political institutions and the political sphere. Instead of overcoming the problematic kind of political exclusion which structures the modern political sphere by establishing new institutional levels, the paper aims to expand the sensitivity and thematic reach of existing political collectives.
Shadow Spaces for Social Learning: A Relational Understanding of Adaptive Capacity to Climate Change within Organisations
Authors: Pelling Mark , High Chris , Dearing John , Smith Denis
Published: June 2007

Recent UK government policy on climate change, and wider policy movement within the United Nations Framework Convention on Climate Change, emphasise the building of adaptive capacity. But what are the institutional constraints that shape capacity to build adaptive organisations? The authors synthesise theory from social learning and institutional aspects of multilevel environmental governance to help unpack the patterns of individual and collective action within organisations that can enhance or restrict organisational adaptive capacity in the face of abrupt climate change. Theoretical synthesis is grounded by empirical work with a local dairy farmers group and two supporting public sector bodies that are both local actors in their own rights and which also shape the operating environment for other local actors (the Environment Agency and the Welsh Assembly and Assembly-sponsored public bodies). Providing space within and between local organisations for individuals to develop private as well as officially sanctioned social relationships is supported as a pathway to enable social learning. It is also a resource for adaptation that requires little financial investment but does call for a rethinking of the personal skills and working routines that are incentivised within organisations.
Constructing Responsibilities for Risk: Negotiating Citizen — State Relationships
Authors: Bickerstaff Karen , Simmons Peter , Pidgeon Nick
Published: June 2007

The paper examines the ways in which citizens negotiate responsibility in relation to various environmental and technological risks. It focuses on the role of agency and the way that this figures in constructions of relations of responsibility between individuals and institutions. A central argument is that, across the different issue contexts, patterns of perceived agency are crucial to understanding the apparent contradiction in citizens' attributions of role-responsibilities for the management of risk. The empirical basis of the paper is a series of twelve reconvened focus groups conducted at locations around England, giving a total of twenty-four meetings, in which citizens discussed six different areas of technological risk: genetically modified (GM) crops, genetic testing, mobile-phone handsets; mobile-phone masts; radioactive waste; and climate change. The authors highlight the problem of citizen ambivalence towards responsibility, tracing it to perceived tensions affecting both citizen and state performances of responsibility, and conclude by discussing the implications for policy and by outlining an agenda for further research.
Children's Sociospatial (re)Production of Disability within Primary School Playgrounds
Authors: Holt Louise
Published: June 2007

There is a contemporary shift in the institutional context of ‘disabled’ children's education in the United Kingdom from segregated special to mainstream schools. This change is tied to wider deinstitutionalised or reinstitutionalised geographies of disabled people, fragile globalised educational ‘inclusion’ agendas, and broader concerns about social cohesiveness. Although coeducating children is expected to transform negative representations of (dis)ability in future society, there are few detailed explorations of how children's everyday sociospatial practices (re)produce or transform dominant representations of (dis)ability. With this in mind, children's contextual and shifting performances of (dis)ability in two case study school playground (recreational) spaces are explored. The findings demonstrate that children with mind—body differences are variously (dis)abled, in comparison with sociospatially shifting norms of ability, which have body, learning, and emotional—social facets. The discussion therefore places an emphasis on the need to incorporate ‘intellectual’ and ‘emotional’ differences more fully into geographical studies of disability and identity. The paper has wider resonance for transformative expectations placed on colocating children with a variety of ‘axes of difference’ (such as gender, ‘race’, ethnicity, and social class) in schools.
Landscape ecology of the burrowing bettong: fire and marsupial biocontrol of shrubs in semi-arid Australia
Authors: Noble James C. , Hik David S. , Sinclair Anthony R. E.
Published: June 2007

Prior to European settlement, medium-sized marsupials, especially bettongs (Bettongia spp.), were widely distributed across arid and semi-arid Australia. Most disappeared rapidly in the late 1800s in the earliest settled rangelands such as the West Darling region of western New South Wales following the spread of domestic herbivores, rabbit invasion, exotic predators and loss of habitat. Because the burrowing bettong (Bettongia lesueur) is the only fossorial macropod species, it left a clearly visible record of its past presence, distribution and habitat preferences in the form of substantial relict warrens, particularly in stony, ‘hard-red’ habitats. With the reduction in fire frequency because of excessive grazing pressures following European settlement in the 19th century, there was a rapid increase in the density of unpalatable native shrubs. We examine the hypothesis that periodic wildfires and browsing by bettongs were together able to regulate shrub densities in semi-arid rangelands in Australia. Information from various sources concerning the effects of fire, rainfall and browsing on the demography of shrubs was used to construct a model of shrub population dynamics. The model indicates the potential for two states for a given bettong density: first, a low shrub density maintained by a combination of periodic fire and bettong browsing; and second, a high shrub density in the absence of fire. These results have broad implications for pastoral and conservation management in Australian semi-arid rangelands.
Relationship between fire frequency and nitrogen limitation on foliage production in a native grassland community in Victoria, Australia
Authors: Morgan J. W.
Published: June 2007

The relationship between fire frequency (annual v. infrequent) and nitrogen (N) limitation to foliage production in a temperate native grassland community in western Victoria, Australia, was assessed over one growing season using a simple ammonium nitrate addition experiment. Fire history affected the magnitude of the vegetation responses to N addition. At the community level, mean live biomass in infrequently-burned grasslands declined by 20 ± 8% in response to N addition. In contrast, mean biomass increased by 60 ± 15% in annually-burned grasslands in response to N addition. Both grasses and forbs responded positively to N addition in annually-burned grasslands, with forbs responding more substantially than grasses. Foliage production in annually-burned native grasslands therefore appears to be constrained by N availability. The results of this study may have important implications for understanding species coexistence and invasion by non-native species in temperate native grasslands.
Faecal near infrared reflectance spectroscopy (F.NIRS) measurements of non-grass proportions in the diet of cattle grazing tropical rangelands
Authors: Coates D. B. , Dixon R. M.
Published: June 2007

Frequent faecal near infrared reflectance spectroscopy (F.NIRS) analyses of faeces from cattle grazing a range of tropical pastures were used to measure the non-grass component, and other aspects, of their diets. Seasonal profiles of non-grass and crude protein in the diet are presented for nine sites from the speargrass, Aristida–Bothriochloa, and Mitchell grass dominated pasture regions, and for three shrubland sites where browse was plentiful. In grass-dominated native pastures of the speargrass and Aristida–Bothriochloa pasture regions of Queensland where little browse was available, non-grass was usually only 5–15% of the diet. Diet non-grass was even lower for a buffel grass pasture. In uncleared eucalypt woodland in the speargrass region, browse may have contributed up to 20% of the diet in the late dry season when grasses were senesced. In regions with abundant browse (e.g. mulga lands and desert upland systems) cattle preferentially selected actively growing grasses and forbs when they were available. With diminishing availability or declining quality of the forbs and grass due to grazing selection and dry conditions, browse increasingly contributed to intake. In Mitchell grass dominated pastures forbs often comprised more than 50% of the diet, and there appeared to be strong selection for forbs during the dry season. Where browse was available in association with Mitchell grass dominated pastures, it appeared to contribute to intake only in the late dry season. Dry season sampling in monsoonal tallgrass and Mitchell grass dominated pastures indicated dietary crude protein to be linearly correlated with diet non-grass, demonstrating the importance of non-grass in the prevention or alleviation of dry season protein deficiency in cattle. Changes in diet selected by cattle in relation to season and rainfall were generally in accord with the previous limited information, largely with sheep, in comparable vegetation systems. The results demonstrate the value of F.NIRS technology to assist understanding of diet selection by grazing cattle in northern Australia.
The first assessment, using a rangeland monitoring system, of change in shrub and tree populations across the arid shrublands of Western Australia
Authors: Watson I. W. , Thomas P. W. E. , Fletcher W. J.
Published: June 2007

For the first time, a region-wide assessment of vegetation change across the southern shrublands of Western Australia is reported, using information from 965 shrubland sites of the Western Australian Rangeland Monitoring System (WARMS). The majority of sites were installed between December 1993 and November 1999, and were reassessed between July 1999 and November 2005, with an average interval of just over 5 years. Shrub and tree species density, canopy area and species richness remained the same or increased on the majority of sites. The results were similar when considered at a species level, with most species showing an increase in density, canopy area and the number of sites on which they were found. Recruitment of new individuals to the population was commonplace on virtually all sites and for virtually all species. High rates of recruitment, on many sites, were observed for long-lived species such as Acacia aneura Benth., A. papyrocarpa Benth., Eremophila forrestii F.Muell. and Maireana sedifolia (F.Muell.) Paul G.Wilson. Increases in density, i.e. where recruitment was higher than mortality, were observed for many shorter lived species which are known to decrease in response to excessive grazing (i.e. decreaser species) such as Ptilotus obovatus (Gaudich.) F.Muell., Atriplex vesicaria Benth., A. bunburyana F.Muell. and Maireana georgei (Diels) Paul G.Wilson. However, this result should be tempered by the understanding that acute degradation processes may still be occurring, especially within and surrounding drainage lines, which are away from where the WARMS sites are typically located. Grazing was implicated in decreased density on some sites, particularly those which had experienced below average seasonal conditions. On these sites, decreaser species were particularly affected.
Engineering nanoscale order into a designed protein fiber
Authors: Papapostolou David , Smith Andrew M. , Atkins Edward D. T. , Oliver Seb J. , Ryadnov Maxim G. , Serpell Louise C. , Woolfson Derek N.
Published: June 2007

We have established a designed system comprising two peptides that coassemble to form long, thickened protein fibers in water. This system can be rationally engineered to alter fiber assembly, stability, and morphology. Here, we show that rational mutations to our original peptide designs lead to structures with a remarkable level of order on the nanoscale that mimics certain natural fibrous assemblies. In the engineered system, the peptides assemble into two-stranded α-helical coiled-coil rods, which pack in axial register in a 3D hexagonal lattice of size 1.824 nm, and with a periodicity of 4.2 nm along the fiber axis. This model is supported by both electron microscopy and x-ray diffraction. Specifically, the fibers display surface striations separated by nanoscale distances that precisely match the 4.2-nm length expected for peptides configured as α-helices as designed. These patterns extend unbroken across the widths (≥50 nm) and lengths (>10 μm) of the fibers. Furthermore, the spacing of the striations can be altered predictably by changing the length of the peptides. These features reflect a high level of internal order within the fibers introduced by the peptide-design process. To our knowledge, this exceptional order, and its persistence along and across the fibers, is unique in a biomimetic system. This work represents a step toward rational bottom-up assembly of nanostructured fibrous biomaterials for potential applications in synthetic biology and nanobiotechnology.
IGFBP3 suppresses retinopathy through suppression of oxygen-induced vessel loss and promotion of vascular regrowth
Authors: Lofqvist Chatarina , Chen Jing , Connor Kip M. , Smith Alexandra C. H. , Aderman Christopher M. , Liu Nan , Pintar John E. , Ludwig Thomas , Hellstrom Ann , Smith Lois E. H.
Published: June 2007

Vessel loss precipitates many diseases. In particular, vessel loss resulting in hypoxia induces retinal neovascularization in diabetic retinopathy and in retinopathy of prematurity (ROP), major causes of blindness. Here we define insulin-like growth factor binding protein-3 (IGFBP3) as a new modulator of vascular survival and regrowth in oxygen-induced retinopathy. In IGFBP3-deficient mice, there was a dose-dependent increase in oxygen-induced retinal vessel loss. Subsequent to oxygen-induced retinal vessel loss,
Igfbp3
−/−
mice had a 31% decrease in retinal vessel regrowth versus controls after returning to room air. No difference in serum insulin-like growth factor 1 (IGF1) levels was observed among groups. Wild-type mice treated with exogenous IGFBP3 had a significant increase in vessel regrowth. This correlated with a 30% increase in endothelial progenitor cells in the retina at postnatal day 15, indicating that IGFBP3 could be serving as a progenitor cell chemoattractant. In a prospective clinical study, we measured IGFBP3 (and IGF1) plasma levels weekly and examined retinas in all premature infants born at gestational ages <32 weeks at high risk for ROP. The mean level of IGFBP3 at 30–35 weeks postmenstrual age (PMA) for infants with proliferative ROP (ROP stages 3>,
n
= 13) was 802 μg/liter, and for infants with no ROP (ROP stage 0,
n
= 38) the mean level was 974 μg/liter (
P
< 0.03). These results suggest that IGFBP3, acting independently of IGF1, helps to prevent oxygen-induced vessel loss and to promote vascular regrowth after vascular destruction
in vivo
in a dose-dependent manner, resulting in less retinal neovascularization.
IGF binding protein-3 regulates hematopoietic stem cell and endothelial precursor cell function during vascular development
Authors: Chang Kyung-Hee , Chan-Ling Tailoi , McFarland Evan L. , Afzal Aqeela , Pan Hao , Baxter Louise C. , Shaw Lynn C. , Caballero Sergio , Sengupta Nilanjana , Calzi Sergio Li , Sullivan Sean M. , Grant Maria B.
Published: June 2007

We asked whether the hypoxia-regulated factor, insulin-like growth factor binding protein-3 (IGFBP3), could modulate stem cell factor receptor (c-kit
+
), stem cell antigen-1 (sca-1
+
), hematopoietic stem cell (HSC), or CD34
+
endothelial precursor cell (EPC) function. Exposure of CD34
+
EPCs to IGFBP3 resulted in rapid differentiation into endothelial cells and dose-dependent increases in cell migration and capillary tube formation. IGFBP3-expressing plasmid was injected into the vitreous of neonatal mice undergoing the oxygen-induced retinopathy (OIR) model. In separate studies, GFP-expressing HSCs were transfected with IGFBP3 plasmid and injected into the vitreous of OIR mice. Administering either IGFBP3 plasmid alone or HSCs transfected with the plasmid resulted in a similar reduction in areas of vasoobliteration, protection of the developing vasculature from hyperoxia-induced regression, and reduction in preretinal neovascularization compared to control plasmid or HSCs transfected with control plasmid. In conclusion, IGFBP3 mediates EPC migration, differentiation, and capillary formation
in vitro
. Targeted expression of IGFBP3 protects the vasculature from damage and promotes proper vascular repair after hyperoxic insult in the OIR model. IGFBP3 expression may represent a physiological adaptation to ischemia and potentially a therapeutic target for treatment of ischemic conditions.
Propagating waves of self-assembly in organosilane monolayers
Authors: Douglas Jack F. , Efimenko Kirill , Fischer Daniel A. , Phelan Fredrick R. , Genzer Jan
Published: June 2007

Wavefronts associated with reaction–diffusion and self-assembly processes are ubiquitous in the natural world. For example, propagating fronts arise in crystallization and diverse other thermodynamic ordering processes, in polymerization fronts involved in cell movement and division, as well as in the competitive social interactions and population dynamics of animals at much larger scales. Although it is often claimed that self-sustaining or autocatalytic front propagation is well described by mean-field “reaction–diffusion” or “phase field” ordering models, it has recently become appreciated from simulations and theoretical arguments that fluctuation effects in lower spatial dimensions can lead to appreciable deviations from the classical mean-field theory (MFT) of this type of front propagation. The present work explores these fluctuation effects in a real physical system. In particular, we consider a high-resolution near-edge x-ray absorption fine structure spectroscopy (NEXAFS) study of the spontaneous frontal self-assembly of organosilane (OS) molecules into self-assembled monolayer (SAM) surface-energy gradients on oxidized silicon wafers. We find that these layers organize from the wafer edge as propagating wavefronts having well defined velocities. In accordance with two-dimensional simulations of this type of front propagation that take fluctuation effects into account, we find that the interfacial widths
w
(
t
) of these SAM self-assembly fronts exhibit a power-law broadening in time,
w
(
t
) ≈
t
β
, rather than the constant width predicted by MFT. Moreover, the observed exponent values accord rather well with previous simulation and theoretical estimates. These observations have significant implications for diverse types of ordering fronts that occur under confinement conditions in biological or materials-processing contexts.
Potent immune-modulating and anticancer effects of NKT cell stimulatory glycolipids
Authors: Chang Ya-Jen , Huang Jing-Rong , Tsai Yi-Chien , Hung Jung-Tung , Wu Douglass , Fujio Masakazu , Wong Chi-Huey , Yu Alice L.
Published: June 2007

α-Galactosylceramide (α-GalCer), a glycolipid that stimulates natural killer T (NKT) cells to produce both T helper (Th)1 and Th2 cytokines, has shown antitumor effects in mice but failed in clinical trials. We evaluated 16 analogs of α-GalCer for their CD1-mediated T cell receptor (TCR) activation of naïve human NKT cells and their anticancer efficacy.In vitro, glycolipids containing an aromatic ring in their acyl tail or sphingosine tail were more effective than α-GalCer in inducing Th1 cytokines/chemokines, TCR activation, and human NKT cell expansion. None of these glycolipids could directly stimulate human dendritic cell maturation, except for a glycolipid with an aromatic ring on the sphingosine tail. Here, we show that glycolipids activated the TCR of NKT cells with phosphorylation of CD3ε, ERK1/2, or CREB, which correlated with their induction of Th1 cytokines. Notably, the extent of NKT cell activation when glycolipid was presented by antigen-presenting cells was greater than when glycolipid was presented by non-antigen-presenting cells.In vivo, in mice bearing breast or lung cancers, the glycolipids that induced more Th1-biased cytokines and CD8/CD4 T cells displayed significantly greater anticancer potency than α-GalCer. These findings indicate that α-GalCer analogs can be designed to favor Th1-biased immunity, with greater anticancer efficacy and other immune-enhancing activities than α-GalCer itself.
The yeast mitochondrial ADP/ATP carrier functions as a monomer in mitochondrial membranes
Authors: Bamber Lisa , Harding Marilyn , Monné Magnus , Slotboom Dirk-Jan , Kunji Edmund R. S.
Published: June 2007

Mitochondrial carriers are believed widely to be dimers both in structure and function. However, the structural fold is a barrel of six transmembrane α-helices without an obvious dimerisation interface. Here, we show by negative dominance studies that the yeast mitochondrial ADP/ATP carrier 2 from
Saccharomyces cerevisiae
(AAC2) is functional as a monomer in the mitochondrial membrane. Adenine nucleotide transport by wild-type AAC2 is inhibited by the sulfhydryl reagent 2-sulfonatoethyl-methanethiosulfonate (MTSES), whereas the activity of a mutant AAC2, devoid of cysteines, is unaffected. Wild-type and cysteine-less AAC2 were coexpressed in different molar ratios in yeast mitochondrial membranes. After addition of MTSES the residual transport activity correlated linearly with the fraction of cysteine-less carrier present in the membranes, and so the two versions functioned independently of each other. Also, the cysteine-less and wild-type carriers were purified separately, mixed in defined ratios and reconstituted into liposomes. Again, the residual transport activity in the presence of MTSES depended linearly on the amount of cysteine-less carrier. Thus, the entire transport cycle for ADP/ATP exchange is carried out by the monomer.
Reactivity-promoting criterion based on internal vibrational energy redistribution
Authors: Mitrić Roland , B̈rgel Christian , Bonǎić-Koutecký Vlasta
Published: June 2007

We propose to introduce intrinsic dynamical properties as a criterion for promoting reactivity of small size noble metal reactive centers relevant for heterogeneous catalysis. To illustrate the concept, collisions between Ag
6
−
or Au
6
−
clusters and molecular oxygen have been investigated with direct
ab initio
molecular dynamics by using DFT. We show that different nature and efficiency of internal vibrational energy redistribution (IVR) during reaction dynamics is responsible for significantly different sticking probabilities of O
2
to gold and to silver clusters. In the case of Au
6
−
and O
2
collisions, resonant IVR occurs between two subunits activating O
2
and promoting subsequent oxidation reactions. In contrast, a dissipative IVR in Ag
6
−
and O
2
molecule prevents O
2
to react with other adsorbates. These findings allow us to introduce the nature of IVR as a criterion for promoting the reactivity of noble metal clusters: Resonant IVR between reactants promotes reactivity toward adsorbates.
Suppression of androgen receptor-mediated gene expression by a sequence-specific DNA-binding polyamide
Authors: Nickols Nicholas G. , Dervan Peter B.
Published: June 2007

Androgen receptor (AR) is essential for the growth and progression of prostate cancer in both hormone-sensitive and hormone-refractory disease. A DNA-binding polyamide that targets the consensus androgen response element binds the prostate-specific antigen (PSA) promoter androgen response element, inhibits androgen-induced expression of PSA and several other AR-regulated genes in cultured prostate cancer cells, and reduces AR occupancy at the PSA promoter and enhancer. Down-regulation of PSA by this polyamide was comparable to that produced by the synthetic antiandrogen bicalutamide (Casodex) at the same concentration. Genome-wide expression analysis reveals that a similar number of transcripts are affected by treatment with the polyamide and with bicalutamide. Direct inhibition of the AR-DNA interface by sequence-specific DNA binding small molecules could offer an alternative approach to antagonizing AR activity.
Evidence for a signaling axis by which intestinal phosphate rapidly modulates renal phosphate reabsorption
Authors: Berndt Theresa , Thomas Leslie F. , Craig Theodore A. , Sommer Stacy , Li Xujian , Bergstralh Eric J. , Kumar Rajiv
Published: June 2007

The mechanisms by which phosphorus homeostasis is preserved in mammals are not completely understood. We demonstrate the presence of a mechanism by which the intestine detects the presence of increased dietary phosphate and rapidly increases renal phosphate excretion. The mechanism is of physiological relevance because it maintains plasma phosphate concentrations in the normal range after ingestion of a phosphate-containing meal. When inorganic phosphate is infused into the duodenum, there is a rapid increase in the renal fractional excretion of phosphate (FE Pi). The phosphaturic effect of intestinal phosphate is specific for phosphate because administration of sodium chloride does not elicit a similar response. Phosphaturia after intestinal phosphate administration occurs in thyro-parathyroidectomized rats, demonstrating that parathyroid hormone is not essential for this effect. The increase in renal FE Pi in response to the intestinal administration of phosphate occurs without changes in plasma concentrations of phosphate (filtered load), parathyroid hormone, FGF-23, or secreted frizzled related protein-4. Denervation of the kidney does not attenuate phosphaturia elicited after intestinal phosphate administration. Phosphaturia is not elicited when phosphate is instilled in other parts of the gastrointestinal tract such as the stomach. Infusion of homogenates of the duodenal mucosa increases FE Pi, which demonstrates the presence of one or more substances within the intestinal mucosa that directly modulate renal phosphate reabsorption. Our experiments demonstrate the presence of a previously unrecognized phosphate gut–renal axis that rapidly modulates renal phosphate excretion after the intestinal administration of phosphate.
Development of a bibliography on religion, spirituality and addictions
Authors: GEPPERT CYNTHIA , BOGENSCHUTZ MICHAEL P. , MILLER WILLIAM R.
Published: June 2007

Introduction and Aims. The aim of this study was to develop a comprehensive annotated public‐domain bibliography of the literature on spirituality and addictions to facilitate future research and scholarship. Design and Methods. A search was conducted of all citations listed in the MEDLINE, PsychINFO and ALTA Religion databases covering a period from 1941 to 2004 using the following search terms: substance abuse, substance dependence, addiction, religion, spirituality. A group of experts in the field then classified each citation according to empirically derived categories. Results. A total of 1353 papers met the search parameters and were classified into 10 non‐exclusive categories: (1) attitudes toward spirituality and substance use, (2) commentaries, (3) spiritual practices and development in recovery, (4) spiritual and religion variables in the epidemiology of substance abuse, (5) psychoactive substances and spiritual experiences, (6) religious and spiritual interventions, (7) literature reviews, (8) measurement of spirituality and addictions, (9) 12‐Step spirituality and (10) youth and development. Discussion and Conclusions. The literature is voluminous, but has focused primarily in a few areas. Common findings included an inverse relationship between religiosity and substance use/abuse, reduced use among those practising meditation and protective effects of 12‐Step group involvement during recovery. Although sound instruments are available for measuring spirituality, studies have tended to use simplistic, often single‐item measures. [Geppert C, Bogenschutz MP, Miller WR. Development of a bibliography on religion, spirituality and addictions. Drug Alcohol Rev 2007;26:389–395]
Evidence‐based policy or policy‐based evidence? The role of evidence in the development and implementation of the Illicit Drug Diversion Initiative
Authors: HUGHES CAITLIN E.
Published: June 2007

Issues. Evidence‐based policy is promoted as the ideal in drug policy, yet public policy theorists suggest that policy‐based evidence may be a more fitting analogy, where evidence is used selectively to support a predetermined policy direction. Approach. The following paper assesses the resonance of this notion to the development of the Illicit Drug Diversion Initiative (IDDI), an apparently pragmatic reform adopted in Australia in 1999 through the Federal Coalition ‘Tough on Drugs’ strategy. It utilises interviews with key informants from the Australian drug policy arena conducted in 2005 to assess the role of evidence in the design and implementation of the IDDI. Key Findings. The current paper shows that while policy‐makers were generally supportive of the IDDI and viewed drug diversion as a more pragmatic response to drug users, they contend that implementation has suffered through a selective and variable emphasis upon evidence. Most notably, the IDDI is not premised upon best‐practice objectives of reducing harm from drug use, but instead on ‘Tough on Drugs’ objectives of reducing drug use and crime. Implications. This paper contends that policy‐based evidence may facilitate the adoption of pragmatic reforms, but reduce the capacity for effective reform. It therefore has both functional and dysfunctional elements. Conclusion. The paper concludes that greater attention is needed to understanding how to mesh political and pragmatic objectives, and hence to maximise the benefits from policy‐based evidence. [Hughes CE. Evidence‐based policy or policy‐based evidence? The role of evidence in the development and implementation of the Illicit Drug Diversion Initiative. Drug Alcohol Rev 2007;26:363–368]
Adolescent use of illicit drugs and adult offending: a Swedish longitudinal study
Authors: STENBACKA MARLENE , STATTIN HÅKAN
Published: June 2007

The main aim of this study was to examine the role of illicit drug use before the age of 18 years in developing a criminal career. The study included 7577 18‐year‐old men conscripted for military service in Stockholm County in 1969/1970. At enrolment they answered questions regarding alcohol and illicit drug use, social background, behavioural factors and health. Data on adult and adolescent criminality were obtained from official registers from the age of 15 to the age of 43. Subjects with self‐reported drug use were registered significantly more often (p ≤ 0.0001) for future drug offences and other non‐drug offences than were subjects with no drug use at all. Irrespective of the number of adolescent offences, if subjects also reported illicit drug use in adolescence, their adult criminal activity was considerably higher than if they had not used any drugs during adolescence. This was also true when examining other risk factors. Generally, adolescent illicit drug use was a risk factor over and above common risk factors for adult criminality. Early prevention of illicit substance use and criminality in adolescence is important in hindering a future criminal career. [Stenbacka M, Stattin H. Adolescent use of illicit drugs and adult offending: a Swedish longitudinal study. Drug Alcohol Rev 2007;26:397–403]
The costs and consequences of three policy options for reducing heroin dependency
Authors: MOORE TIMOTHY J. , RITTER ALISON , CAULKINS JONATHAN P.
Published: June 2007

Introduction and Aims. This study compares the costs and consequences of three interventions for reducing heroin dependency: pharmacotherapy maintenance, residential rehabilitation and prison. Design and Methods. Using Australian data, the interventions' cost‐consequence ratio was estimated, taking into consideration reduction in heroin use during the intervention; the length of intervention; and post‐intervention effects (as measured by abstinence rates). Sensitivity analyses were conducted, including varying the magnitude and duration of treatment effects, and ascribing positive outcomes only to treatment completers. A hybrid model that combined pharmacotherapy maintenance with a prison term was also considered. Results. If the post‐programme abstinence rates are sustained for 2 years, then for an average heroin user the cost of averting a year of heroin use is approximately AUD$5000 for pharmacotherapy maintenance, AUD$11 000 for residential rehabilitation and AUD$52 000 for prison. Varying the parameters does not change the ranking of the programmes. If the completion rate in pharmacotherapy maintenance was raised above 95% (by the threat of prison for non‐completers), the combined model of treatment plus prison may become the most cost‐effective option. Discussion and Conclusions. Relative performance in terms of costs and consequences is an important consideration in the policy decision‐making process, and quantitative data such as those reported herein can provide insights pertinent to evidence‐based policy. [Moore TJ, Ritter A, Caulkins JP. The costs and consequences of three policy options for reducing heroin dependency. Drug Alcohol Rev 2007;26:369–378]