bluuebunny/crossref_metadata_2025 huggingface dataset:
Resonance Raman scattering of relaxors PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3
Authors: Mihailova B. , Bastjan M. , Schulz B. , Rübhausen M. , Gospodinov M. , Stosch R. , Güttler B. , Malcherek T. , Bismayer U.
Published: January 2007

Relaxor PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3 single crystals are studied at room temperature using resonance Raman scattering. It is shown that the phonon modes associated with O localized BO6 vibrations in ferroic clusters strongly resonate in the vicinity of the maximum of the optical dielectric response function at 3.71eV. Resonance Raman spectroscopy can be used to estimate the fraction and the average size of polar nanoclusters in the relaxor state.
High field-effect mobility ZnO thin-film transistors with Mg-doped Ba0.6Sr0.4TiO3 gate insulator on plastic substrates
Authors: Kang KyongTae , Lim Mi-Hwa , Kim Ho-Gi , Kim Il-Doo , Hong Jae-Min
Published: January 2007

The authors report on the influence of Mg acceptor doping on the markedly reduced leakage current characteristics (<5×10−8A∕cm2 at 2MV∕cm) of Ba0.6Sr0.4TiO3 thin films. The suitability of room temperature deposited Mg-doped Ba0.6Sr0.4TiO3 films as gate insulators for low-voltage ZnO thin-film transistors (TFTs) (<6V) was investigated. All room temperature processed ZnO-TFTs on plastic substrates exhibited a high field-effect mobility of 16.3cm2∕Vs and a current on/off ratio of 6.4×104. The threshold voltage and subthreshold swing were 2.8V and 400mV/decade, respectively.
Insights on the physical mechanism behind negative bias temperature instabilities
Authors: Houssa M. , Afanas’ev V. V. , Stesmans A. , Aoulaiche M. , Groeseneken G. , Heyns M. M.
Published: January 2007

Negative bias temperature instabilities are studied on metal-oxide-semiconductor structures, with hydrogen-passivated and depassivated (H-free) (111) and (100)Si∕SiO2 interfaces. By combining electrical and electron-spin resonance measurements, it is found that Pb∕Pb0 centers are generated on passivated surfaces, while their density is reduced on depassivated surfaces. These results suggest the liberation of atomic hydrogen species in the gate stack followed by their transport towards the Si∕SiO2 interface and reaction with the Pb and PbH centers. It is shown that these species are likely not released from the Si substrate. Alternatively, the authors propose that they may result from the cracking of hydrogen- and water-related species at or close to the metal/SiO2 interface when the device is subjected to negative bias temperature stress.
Mechanisms of free-surface breakup in vibration-induced liquid atomization
Authors: Vukasinovic Bojan , Smith Marc K. , Glezer Ari
Published: January 2007

The mechanisms of droplet formation that take place during vibration-induced drop atomization are investigated experimentally. Droplet ejection results from the breakup of transient liquid spikes that form following the localized collapse of free-surface waves. Breakup typically begins with capillary pinch-off of a droplet from the tip of the spike and can be followed by additional pinch-offs of satellite droplets if the corresponding capillary number is sufficiently small (e.g., in low-viscosity liquids). If the capillary number is increased (e.g., in viscous liquids), breakup first occurs near the base of the spike, with or without subsequent breakup of the detached, thread-like spike. The formation of these detached threads is governed by a breakup mechanism that is separated from the tip-dominated capillary pinch-off mechanism by an order of magnitude in terms of dimensionless driving frequency f*. The dependence of breakup time and unbroken spike length on fluid and driving parameters is established over a broad range of dimensionless driving frequencies (10−3<f*<1). It is also shown that the droplet-ejection acceleration threshold âc of low-viscosity liquids depends on the dimensionless drop diameter d̂. Moreover, in the limit d̂⩾20, the droplet-ejection threshold becomes independent of d̂ (âc≈4). This limit state is described by a scaling equivalent to that of Goodridge, Shi, and Lathrop [Phys. Rev. Lett. 76, 1824 (1996)] derived for the onset of droplet ejection from Faraday waves. It is shown in the present study that the acceleration threshold in this limit scales like ac∼f4∕3(σ∕ρ)1∕3.
Silicon oil: A cheap liquid additive for enhancing in-field critical current density in MgB2
Authors: Wang X. L. , Cheng Z. X. , Dou S. X.
Published: January 2007

In this work, the authors report on significant flux pinning enhancement in MgB2 that has been easily obtained using a liquid additive, silicon oil. MgB2 bulk samples with 0 up to 30wt% silicon oil added were prepared by an in situ reaction. Results showed that the Si and C released from the decomposition of the silicon oil formed Mg2Si and substituted into B sites, respectively. Increasing the amount of the Si oil up to 15wt% has resulted in the reduction of the lattice parameters, as well as Tc and R(300K)∕R(Tc) values, accompanied by a significant enhancement of Jc(H), Hirr, and Hc2.
Characterization of proton irradiated copolymer thin films for microelectromechanical system applications
Authors: Lam T. Y. , Lau S. T. , Chao C. , Chan H. L. W. , Choy C. L. , Cheung W. Y. , Wong S. P.
Published: January 2007

The electrostrictive response of proton irradiated poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] thin films, deposited on silicon (Si) substrates, has been characterized. By applying an ac field to the copolymer films, the induced surface displacement of the film along the thickness direction was measured using a laser interferometer. After the proton irradiation, the electric field induced strain response of the copolymer film is enhanced. Since the copolymer films are laterally clamped by the rigid substrate, the films cannot vibrate freely. At a proton dose of 50Mrad, the effective electrostrictive coefficient Meff,33 of P(VDF-TrFE) thin film on Si is 0.07×10−18V2∕m2 which is ∼25 times smaller than that of bulk sample under the same irradiation dose (M33=1.76×10−18V2∕m2). Using bulk micromachining to etch away most of the Si substrate, an actuator in the form of a suspended membrane was fabricated. The effective electrostrictive coefficient at the center of the membrane Meff,33′ increased to 0.67×10−18V2∕m2 due to the weakening of the substrate clamping effect. The resonance characteristics of the actuators based on these irradiated copolymer films were studied.
Liquid-state field-effect transistors using electrowetting
Authors: Kim D. Y. , Steckl A. J.
Published: January 2007

The authors report the demonstration of transistor action in the liquid state. The control of current flow in a liquid field-effect transistor (LiquiFET) was achieved by electrowetting between competitive insulating/conducting fluids. The LiquiFET structure included dielectric/hydrophobic layers, source/drain regions, a gate electrode, and hydrophilic/hydrophobic grids to contain the liquids. For a 400μm long channel, turn-on occurs at 2.5–3V drain voltage. On/off current ratios >10000:1 were measured. Linear gate voltage control over drain current was obtained with a transconductance up to 40nS. A calculated channel mobility of ∼1cm2∕Vs indicates that electronic charge transport dominates transistor operation.
Multidirectional observation of an embedded quantum dot
Authors: Kita Takashi , Inoue Tomoya , Wada Osamu , Konno Mitsuru , Yaguchi Toshie , Kamino Takeo
Published: January 2007

The authors succeeded in observing atomic scale images of undamaged single InAs quantum dots (QDs) embedded in the GaAs matrix using high resolution transmission electron microscope equipped with focused ion beam system. The QD can be viewed from multidirections, and a conclusive and comprehensible determination of the size and the shape anisotropy has been realized. Asymmetry of the structural properties has been confirmed between the [110] and [−110] crystal directions. The embedded QD is elongated along the [−110] axis. The strain-field pattern is also asymmetric according to the shape anisotropy. The results will enable the investigation of the exact structure anisotropy influencing the atomlike properties of QDs.
Connecting nitrogenase intermediates with the kinetic scheme for N
2
reduction by a relaxation protocol and identification of the N
2
binding state
Authors: Lukoyanov Dmitriy , Barney Brett M. , Dean Dennis R. , Seefeldt Lance C. , Hoffman Brian M.
Published: January 2007

A major obstacle to understanding the reduction of N
2
to NH
3
by nitrogenase has been the impossibility of synchronizing electron delivery to the MoFe protein for generation of specific enzymatic intermediates. When an intermediate is trapped without synchronous electron delivery, the number of electrons,
n
, it has accumulated is unknown. Consequently, the intermediate is untethered from kinetic schemes for reduction, which are indexed by
n
. We show that a trapped intermediate itself provides a “synchronously prepared” initial state, and its relaxation to the resting state at 253 K, conditions that prevent electron delivery to MoFe protein, can be analyzed to reveal
n
and the nature of the relaxation reactions. The approach is applied to the “H
+
/H
−
intermediate” (
A
) that appears during turnover both in the presence and absence of N
2
substrate.
A
exhibits an
S
= ½ EPR signal from the active-site iron–molybdenum cofactor (FeMo-co) to which are bound at least two hydrides/protons.
A
undergoes two-step relaxation to the resting state (
C
):
A
→
B
→
C
, where
B
has an
S
= 3/2 FeMo-co. Both steps show large solvent kinetic isotope effects:
KIE
≈ 3–4 (85% D
2
O). In the context of the Lowe–Thorneley kinetic scheme for N
2
reduction, these results provide powerful evidence that H
2
is formed in both relaxation steps, that
A
is the catalytically central state that is activated for N
2
binding by the accumulation of
n
= 4 electrons, and that
B
has accumulated
n
= 2 electrons.
Doing the right thing with water: combining market-based principles with policy intervention for the sustainable management of water in agriculture.
Authors: Msangi S. , Ringler C. , Rosegrant M.
Published: January 2007

The increasing importance of sustainability in natural resource management is drawing increasing attention, worldwide, to the role that policies can play in enhancing the management and allocative efficiency of water. Looking at various examples from the literature, we discuss some best practices that have been applied in a variety of empirical settings, while highlighting some of the pitfalls to avoid. We discuss the role that assigning water rights can play in creating the necessary incentives for market-based mechanisms of re-allocation to work for water management. We also emphasize the role that remains for centralized regulatory authority, and the need for collective action to ensure that essential ecosystem requirements are met. Among the variety of examples cited are those of inter-sectoral transfers, conjunctive use of surface and groundwater and tradable permit mechanisms for which we also highlight the enabling institutional requirements.
Cloning livestock.
Authors: Wells D. N.
Published: January 2007

An efficient animal cloning technology, using the procedure of nuclear transfer (NT), would provide many new opportunities for livestock agriculture, animal conservation and biomedicine. Although it is 10 years since the birth of Dolly, the first animal to be cloned from an adult cell, it is still remarkable that NT using differentiated donor cells can produce physiologically normal cloned animals. But the process is very inefficient, poorly understood and appears highly prone to epigenetic errors. With the present technology, only up to 6% of the embryos transferred to the reproductive tracts of recipient females typically result in long-term surviving clones. Not only are there high losses throughout gestation, during birth and in the immediate post-natal period, but also throughout adulthood. Many of the pregnancy losses relate to failure of the placenta to develop and function correctly. Placental dysfunction may also have an adverse influence on postnatal viability and health. These anomalies are probably due to incorrect epigenetic reprogramming of the donor genome following NT, leading to inappropriate patterns of gene expression during the development of clones. While some physiological tests on surviving clones suggest normality, other reports indicate a variety of post-natal clone-associated abnormalities. Importantly, it appears that these clone-associated phenotypes are not transmitted to offspring following sexual reproduction. This indicates that they represent epigenetic errors which are corrected during gametogenesis. While this requires molecular confirmation, it provides initial confidence in the first application of NT in agriculture, namely, the production of small numbers of cloned sires from genetically elite males, for natural mating, to effectively disseminate genetic gain. Considerably more efficient cloning methods will be required for large-scale dissemination of whole genotypes of elite livestock from nucleus herds directly to commercial producers. The continual advances in animal genomics towards the identification of genes that influence livestock production traits and human health serve to increase the ability to genetically modify cultured cells, prior to NT, to generate livestock with increased productivity or that produce superior quality food and biomedical products for niche markets. The potential opportunities for animal agriculture are more challenging because of the greater demands on cost, efficiency, consumer acceptance and relative value of the product to be viable in contrast to biomedical applications. Hence, the integration of this technology into practical farming systems remains some time in the future.
Assessing public perception of landscape: past, present andfuture perspectives.
Authors: Scott A.
Published: January 2007

Academics and policy-makers seeking to assess public perception and preferences of landscape face major challenges conceptually, methodologically and institutionally. The terms landscape, public and perception are contested and generate their own discourses and extensive literature. However, set within multi-disciplinary and interdisciplinary blends of natural and social scientificresearch, considerable progress has been made on all fronts. This paper seeks to untangle the complex array of conceptual and methodological frameworks that have evolved in landscape perception. In such respects, special attention has been placed on the cultural, humanistic and visual approaches set within an emerging landscape science. The paper also assesses the extent to which developments in research have been translated into policy. The paper concludes that although progress has been made there are still significant institutional barriers and inertia preventing a change of landscape culture that is now required.
New weed threats: extent, origins, and proper management.
Authors: Weber E. , Schrader G.
Published: January 2007

Weed problems continue to be an obstacle in plant protection and in natural areas, causing high costs of control and asking for adequate prevention measures. New weed problems in any given area (risk area) may arise from three basic sources: by introduction and naturalization of new weedy plant species, by increasing spread of weedy taxa that are already present in the risk area, and by the evolution of new weedy taxa in the risk area. Introduction and subsequent naturalization of new plant species is taking place worldwide and the number of alien plant species being introduced is steadily increasing. Newly recorded alien plant species prevail in disturbed sites and semi-natural habitats, increasing the risk for new plant invasions into areas of high conservation value. New weed problems in agroecosystems are associated with recently naturalized species, with adaptation and evolution of plant species, but also due to land use change, global warming, and changes in the environmental conditions. These may affect the dynamics of weed populations, triggering sudden range expansion and abundance increase. Evolution of new weedy taxa involves crop/weed hybridization, hybridization between native and alien plants in the risk area, and hybridization between formerly separated taxa that co-occur in the risk area. Evolution of herbicide resistance is another source of new weed taxa. A literature survey revealed more than 40 new weed species of agroecosystems within the last 20 years and about 35 new plant species invading natural and semi-natural habitats during the last ten years. Measures towards mitigating problems associated with new weeds includes regular monitoring and risk assessments, aiming at preventing entry of new weeds and prioritizing weed species for control.
Crop diversification through halophyte production on salt-prone land resources.
Authors: Khan M. A. , Ansari R. , Gul B. , Qadir M.
Published: January 2007

Rapid population growth in the less developed countries of arid and semiarid regions and concomitant decline in productivity of agricultural lands due to shortage of good-quality irrigation water and increasing soil salinity, are exerting enormous pressure on the dwindling supplies of human consumption for food. Equally or even more affected in some cases are other resources, such as fodder for animals and fuel wood for the rural poor. There is growing evidence that this trend is unlikely to reverse at least in the near future. The last quarter of the 20th century has seen an explosion of information leading to a better understanding of the biology of salt tolerance in plants. Most conventional crops have marginal salt tolerance and there is a need to explore alternate options for utilization of salt-affected lands and saline water resources. Research has indicated the potential of many halophytes to withstand high soil salinity and saline water irrigation, some even with seawater. This tolerance is achieved through a number of adaptations such as selective uptake and transport of ions, localization of ions in vacuoles, synthesis of compatible organic solutes for cytoplasmic balancing and protection of enzyme systems. As a consequence, these plants are able to reduce damage and exhibit sustained growth by establishing homeostatic conditions. A wealth of halophytic flora exists which can be exploited for an array of uses like food, fodder, fuel wood, oilseed, medicines, chemicals, landscaping, ornamentals, and environment conservation through carbon sequestration.
Genetic variants of milk proteins and their effects on the yieldand quality of cheese.
Authors: Ng-Kwai-Hang K. F.
Published: January 2007

Milk protein genes, which are inherited by simple Mendelian genetics, could be used as marker traits for production and milk compositional traits. Genetic variants of certain milk proteins have been shown to be associated with coagulating properties of milk, cheese yield and cheese composition. In most of the cases, the observed differences in cheesemaking properties between some genetic variants are the result of their associations with the levels of fat and casein in the milk, which significantly influence cheese yield and composition. However, in some instances, differences between genetic variants are the result of the direct effect as a result of substitution of amino acids along the polypeptide chain leading to a change in the conformation and hence altering the physiochemical properties of the protein. Differences in heat stability, protein/protein interactions, and rate of proteolysis of different genetic variants are some examples of the direct effects in some cheese varieties. In bovine species, most studies have demonstrated that the B variant of κ-casein and the B variant of β-lactoglobulin (which are associated with higher levels of fat and casein in the milk) give higher cheese yield and better cheese composition than the A variant of the two proteins. Most research on caprine milk has concentrated on the αas1-casein loci. Variant A, which is associated with higher levels of synthesis of αs1-casein and total casein, is more suitable for cheese production than either variant E or F. In the ovine species, it has been shown that variant D of αs1-casein is not favourable for cheesemaking, while β-lactoglobulin A milk is more suitable than β-lactoglobulin B for the making of cheese.
Perspectives on the development of genetically modified arthropodnatural enemies for agricultural pest management programmes.
Authors: Hoy M. A.
Published: January 2007

The history of genetic improvement of arthropod natural enemies is reviewed briefly and I describe the successful genetic improvement and deployment in California almond orchards of a pesticide-resistant predatory mite. Lessons learned from our efforts to deploy this and other natural enemies in alfalfa [lucerne], citrus and walnuts from several genetic improvement projects conducted over the past 30 years are described, because they may provide useful lessons for future projects. Gaps in our knowledge are identified, especially in deploying such genetically modified natural enemies, and recommendations are made regarding how to plan such projects. Finally, issues of risk and regulation are discussed based on our experiences with a short-term field trial of a transgenic predatory mite in Florida.
Interactions between fire, climate change and forest biodiversity.
Authors: Nitschke C. R. , Innes J. L.
Published: January 2007

The interactions between climate change, fire and forest biodiversity can be characterized as a cascading relationship. Changes in climate directly affect fire frequency and severity. As a result of climate change, a significant increase in fire occurrence and behaviour is predicted to occur over the next 70 years. Climate change will also directly impact the composition of current ecosystems by shifting the fundamental niche of species to higher elevations and/or latitudes, with the changes being most apparent in temperate and boreal latitudes and on mountains in the tropics and subtropics. The alteration and shift of forest ecosystems will be facilitated by an increase in the frequency and severity of forest fires, as these ecosystem disturbances will create the opportunity for the development of new ecosystems. Warmer, drier conditions, coupled with a change in fire behaviour will reduce the resilience of existing ecosystems. The reduced ability to resist and/or recover from disturbance will result in the reduction or complete loss of ecosystem structures required by the fauna and flora that constitute the biodiversity we currently know today. Areas of climatic refuge that exist within landscapes may maintain the ecosystem structures required for some species in the face of direct climate change impacts. Areas that act as both fire and climatic refugia will provide habitat for biodiversity associated with late-successional forests. Species that require late-successional habitat in ecosystems that are intolerant of fire or drought are at greatest risk to climate change and its interaction with fire. The current composition of biodiversity within forested landscapes will change over time and space as species and habitat are both lost and gained in direct or indirect response to climate change.
Lycopene: prospects for chemoprevention and treatmentof prostate cancer.
Authors: Heath E. , Sahin K. , Seren S. , Kucuk O.
Published: January 2007

Lycopene is a carotenoid compound found in certain fruit, such as tomato, watermelon, pink grapefruit and guava in high concentrations. Dietary intake of lycopene is inversely associated with the risk of prostate cancer (Pca). Preclinical studies show that lycopene has potent
in vitro
and
in vivo
anti-tumour effects on Pca cells suggesting potential preventive and therapeutic roles for this phytochemical. However, the small number and size of clinical trials conducted with lycopene preclude firm conclusions with regard to its use in Pca prevention and treatment in humans. Further research, including hypothesis-driven mechanistic studies as well as larger randomized clinical intervention trials with lycopene in Pca patients, are warranted.
Challenges to ensuring food security through rice.
Authors: Nguyen N. V.
Published: January 2007

Rice is the major staple food of the world's population. In 2003, more than 3 billion people depended on rice for food energy and protein. Global rice production has more than doubled since 1965. The production increase was largely the result of rising yields and of the expansion in rice-harvested area. From 1965 to 2005, the world's average rice yield increased by 97%, while the global rice area harvested increased by 23%. Global paddy production reached about 618 million tonnes in 2005, a level sufficient to meet total rice needs and permit a reconstitution of world rice reserves for the first time after five years of draw-downs. The world population is still growing steadily and the world's rice demand is projected to increase by 25% to 771 million tonnes of milled rice in 2030. The development and adoption of high-yielding varieties and hybrid rice varieties were key instruments behind the substantial yield increase witnessed in the last 40 years in all regions, except in sub-Saharan Africa, where yields have remained more or less unchanged. The development of irrigation and the intensive application of agro-chemical inputs, especially chemical fertilizers, were other major factors contributing to the rapid yield increase of the last 40 years. However, the rate of increases in productivity has steadily declined since 1990, while agricultural water resources have been diminishing in Asia, North Africa and Europe. Results of the pilot tests since 2000 have demonstrated the potential contribution of integrated crop management systems for rice production (Rice-ICM systems) for ensuring food security in the medium term. Yield increases of up to 4 tonnes/ha were obtained from existing varieties with the adoption of Rice-ICM systems in Asia and South America. Also, experience drawn from the limited area planted to hybrid rice outside China and from the newly developed NERICA (New Rice for Africa) rice for sub-Saharan Africa shows the potential benefits that the dissemination of these rice varieties might bring in enhancing food security in the medium term. In the longer term, the development and transfer of Rice-ICM systems that not only increase yield but also increase the utilization efficiency of applied purchased inputs will be essential for ensuring food security and environment sustainability. It is expected that the mapping of the rice genome in 2002 will lead to a successful development of new generations of rice varieties that will further contribute to raising the productivity of rice production systems in the longer term.
Distinct gene subsets are induced at different time points after human respiratory syncytial virus infection of A549 cells
Authors: Martínez Isidoro , Lombardía Luis , García-Barreno Blanca , Domínguez Orlando , Melero José A.
Published: January 2007

cDNA microarray technology was applied to time course analysis of differentially expressed genes in A549 cells following human respiratory syncytial virus (HRSV) infection. Both up- and down-regulation of cellular genes were observed in a time-dependent manner. However, gene up-regulation prevailed over gene down-regulation. Virus infectivity was required as UV-inactivated virus failed to up-regulate/down-regulate those genes. At early times post-infection (0–6 h p.i.) 85 genes were up-regulated. Some of those genes were involved in cell growth/proliferation, cellular protein metabolism and cytoskeleton organization. Among the most strongly up-regulated genes at that time were the urokinase plasminogen activator (PLAU) and its receptor (PLAUR), a pleiotropic system involved in many biological processes, including chemotaxis and inflammation. Functionally related genes encoding theα- andβ-chains of several integrins were also up-regulated within the first 12 h of infection. Genes up-regulated between 6 and 12 h p.i. included interferon-stimulated genes (ISGs), genes related to oxidative stress and genes of the non-canonical NF-κB pathway. At later times, genes involved in the immune response became predominant among the up-regulated genes, most of them being ISGs. Different up-regulation kinetics of cytokine and cytokine-signalling-related genes were also observed. These results highlight the dynamic interplay between the virus and the host cell and provide a general picture of changes in cellular gene expression along the HRSV replicative cycle.
Zinc-binding domain of rotavirus NSP1 is required for proteasome-dependent degradation of IRF3 and autoregulatory NSP1 stability
Authors: Graff Joel W. , Ewen Julie , Ettayebi Khalil , Hardy Michele E.
Published: January 2007

Interferon regulatory factor 3 (IRF3) is a key transcription factor involved in the induction of interferon (IFN) in response to viral infection. Rotavirus non-structural protein NSP1 binds to and targets IRF3 for proteasome degradation early post-infection. Mutational analysis of cysteine and histidine residues within the conserved N-terminal zinc-binding domain in NSP1 of bovine rotavirus strain B641 abolished IRF3 degradation in transfected cells. Thus, the integrity of the zinc-binding domain in NSP1 is important for degradation of IRF3. In contrast to bovine strain B641, IRF3 was stable in cells infected with porcine rotavirus strain OSU and OSU NSP1 bound only weakly to IRF3. Both B641 NSP1 and OSU NSP1 were stabilized in cells or cell-free extracts in the presence of the proteasome inhibitor MG132 and when the zinc-binding domain was disrupted by site-directed mutagenesis. Data from the B641 analyses that show IRF3 degradation is dependent on the presence of NSP1 and the integrity of the N-terminal zinc-binding domain, coupled with the regulated stability of IRF3 and NSP1 by the proteasome, collectively support the hypothesis that NSP1 is an E3 ubiquitin ligase.
Early restriction of alphavirus replication and dissemination contributes to age-dependent attenuation of systemic hyperinflammatory disease
Authors: Ryman Kate D. , Gardner Christina L. , Meier Kathryn C. , Biron Christine A. , Johnston Robert E. , Klimstra William B.
Published: January 2007

Severity of alphavirus infection in humans tends to be strongly age-dependent and several studies using laboratory-adapted Sindbis virus (SB) AR339 strains have indicated that SB-induced disease in mice is similarly contingent upon host developmental status. In the current studies, the consensus wild-type SB, TR339, andin vivoimaging technology have been utilized to examine virus replication and disease manifestations in mice infected subcutaneously at 5 days of age (5D) vs 11D. Initial virulence studies with TR339 indicated that this age range is coincident with rapid transition from fatal to non-fatal outcome. Fatal infection of 5D mice is characterized by high-titre serum viraemia, extensive virus replication in skin, fibroblast connective tissue, muscle and brain, and hyperinflammatory cytokine induction. In contrast, 11D-infected mice experience more limited virus replication and tissue damage and develop mild, immune-mediated pathologies including encephalitis. These results further establish the linkage between hyperinflammatory cytokine induction and fatal outcome of infection.In vivoimaging using luciferase-expressing viruses and non-propagative replicons revealed that host development results in a restriction of virus replication within individual infected cells that is manifested as a delay in reduction of virus replication in the younger mice. Thus, an important contributing factor in age-dependent resistance to alphavirus infection is restriction of replication within first infected cells in peripheral tissues, which may augment other developmentally regulated attenuating effects, such as increasing neuronal resistance to virus infection and apoptotic death.
Multimerization of human cytomegalovirus regulatory protein UL69 via a domain that is conserved within its herpesvirus homologues
Authors: Lischka Peter , Thomas Marco , Toth Zsolt , Mueller Regina , Stamminger Thomas
Published: January 2007

The UL69 protein of human cytomegalovirus is a multifunctional regulatory protein that has counterparts in all herpesviruses. Some of these proteins have been shown to function primarily at the post-transcriptional level in promoting nuclear export of viral transcripts. Consistently, this group has reported recently that pUL69 is an RNA-binding, nucleocytoplasmic shuttling protein that facilitates the cytoplasmic accumulation of unspliced mRNA via its interaction with the cellular mRNA export factor UAP56. Evidence has been presented to suggest that some of the pUL69 homologues self-interact and function in vivo as multimers. Herein, the possibility of pUL69 self-association was examined and it has been demonstrated that pUL69 can interact with itself in vitro and in vivo in order to form high-molecular-mass complexes. The self-interaction domain within pUL69 was mapped to a central domain of this viral protein that is conserved within the homologous proteins of other herpesviruses, suggesting that multimerization is a conserved feature of this protein family.
Effect of ocean conditions on the cross‐shelf distribution of walleye pollock (Theragra chalcogramma) and capelin (Mallotus villosus)
Authors: HOLLOWED ANNE BABCOCK , WILSON CHRISTOPHER D. , STABENO PHYLLIS J. , SALO SIGRID A.
Published: January 2007

Acoustic trawl surveys were conducted in 2000 and 2001 in two troughs located off the eastern coast of Kodiak Island in the Gulf of Alaska as part of a multiyear, multidisciplinary experiment to examine the influence of environmental conditions on the spatial distribution of adult and juvenile walleye pollock (Theragra chalcogramma) and capelin (Mallotus villosus). Continuous underway sea surface temperature samples and water column profiles collected in 2000 and 2001 showed the presence of a sharp shelf‐break front in Chiniak Trough and a mid‐trough front in Barnabas Trough. At distances <22 km from shore, the water column was well mixed, whereas a well‐defined mixed layer was present beyond approximately 22 km from shore. Satellite drifter tracks in Barnabas Trough entered along the upstream edge of the trough and appeared to follow the frontal boundary across the middle portion of the trough. A storm in 2001 weakened stratification and cooled surface water temperature by 1.6–2.1°C. Wind mixing associated with the storm event mixed subsurface chlorophyll a to the surface and enhanced nutrients in the surface waters. The storm event revealed spatial partitioning of summer production in Barnabas Trough, with production concentrated in regions inside the mid‐trough front. In contrast, post‐storm summer production was distributed throughout Chiniak Trough. The spatial distribution of walleye pollock and capelin differed and appeared to be related to differences in habitat characteristics. Acoustic survey data identified four acoustic sign types: age‐1 pollock, adult pollock, capelin, capelin–age‐0 pollock mix. The spatial distribution of these four sign types appears to be influenced by the oceanographic and topographic features of the two troughs. Adult pollock were broadly distributed throughout Chiniak Trough, whereas adult pollock were aggregated on the coastal side of the frontal system in Barnabas Trough. In 2000, capelin occurred with age‐0 pollock. In Chiniak Trough, capelin were most abundant along steep topographic gradients at the edges of the trough and in a deep region near Cape Chiniak, whereas the capelin–age‐0 mix (2000) or capelin (2001) concentrations were observed in slope water intrusions over the outer shelf in Barnabas Trough. Results suggest that habitat selection of walleye pollock and capelin are controlled by different processes. Capelin distributions appear to be limited by oceanographic conditions while other factors appear to be more important for pollock.
Multicentric giant cell tumours in an adolescent with haemophilia
Authors: CHANG C.‐C. , CHANG S.‐T. , CHANG H.‐Y. , LIN G.‐M. , LAI M.‐H. , CHIANG S.‐L.
Published: January 2007

Summary.  ‘‘Multicentric giant cell tumour (GCTs) of the extremity is prone to be distributed over the age range of 20–40 years, but is rare in haemophilia and in the age before 20. We report a case of a 15‐year‐old haemophilia boy who presented initially with two radiolucent loci in the right femur and tibia revealed from the X‐ray films and then another lesion in the posterior femoral shaft shown from MRI by one year. Differential diagnosis of GCTs should be appraised in various aspects. Radiological diagnostic pitfall was avoided by the pathology disclosed GCTs without malignancy. The early diagnosis of GCTs in haemophilia may be delayed unless appearance of symptoms of pathologic fracture. Coincident multicentric GCTs do occur in haemophilic patients and their incidence might be underestimated, as it might not be judged because immediate symptoms of pain would resolve with appropriate factor replacement.”
Autistic enterocolitis; is it a histopathological entity?
Authors: MacDonald T T , Domizio P
Published: January 2007

Aims:  To review the literature on the histopathological diagnosis of the condition termed ‘autistic enterocolitis’.

Methods and results:  We have reviewed all published works where mucosal biopsy specimens from autistic children have been examined histopathologically. Abstracts were excluded. Our review of the published works, nearly all from a single centre, identifies major inconsistencies between studies, lack of appropriate controls and misinterpretation of normal findings as pathology. Ileal lymphoid hyperplasia may be more prevalent in children with regressive autism but is also seen in children with food allergies and severe constipation, the latter being an extremely common finding in autistic children.

Conclusion:  The histopathological diagnosis of autistic enterocolitis should be treated with caution until a proper study with appropriate methodology and controls is undertaken.
Phenotypes of invasion in sporadic colorectal carcinomas related to aberrations of the adenomatous polyposis coli (APC ) gene
Authors: Prall F , Weirich V , Ostwald C
Published: January 2007

Aims:  To determine whether the dissociation of tumour cells from neoplastic glands in colorectal carcinomas is caused by disruption of the wnt‐signalling pathway and whether the adenomatous polyposis coli (APC) protein is implicated in this.

Methods and results:  In a series of 99 clinically sporadic colorectal carcinomas, APC exon 15 mutations, loss of heterozygosity (LOH) and promoter methylation were found in 49, 20 and 23 cases, respectively. Singly, these APC aberrations were not associated with the degree of tumour cell dissociation, but dissociation was higher for the cases with combined APC mutation and LOH. Immunohistochemical β‐catenin translocation to the nucleus correlated with APC aberrations. Tumour growth pattern (expansive/infiltrative/diffuse) and tumour stroma (desmoplastic common‐type versus keloid‐like) showed a statistically significant association with tumour cell dissociation and with β‐catenin translocation. Of other molecular alterations tested (p53 mutation; LOH at 17p13, 18q, 9p21; CpG island methylator phenotype), only the highly microsatellite unstable status (n = 11) was negatively associated.

Conclusions:  In colorectal carcinomas, wnt dysregulation relates to APC aberrations, but wnt dysregulation and APC aberrations are not strictly required for tumour cell dissociation, and additional and/or alternative factors must play a role. Of these, outside‐in signalling by cancer cell–matrix interactions, as partially mirrored in histomorphological features, could be important.
Does the Trans‐mexican Volcanic Belt represent a natural biogeographical unit? An analysis of the distributional patterns of Coleoptera
Authors: Corona Angélica Ma. , Toledo Víctor H. , Morrone Juan J.
Published: January 2007

Aim We analysed the geographical distribution of beetle species of the families Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae from the Trans‐mexican Volcanic Belt (TVB) through a track analysis and a parsimony analysis of endemicity (PAE), in order to test its naturalness and determine its affinities.

Location The area analysed corresponds to the TVB, which is a biogeographical province of the Mexican Transition Zone.

Methods The panbiogeographical analysis was based on the comparison of the individual tracks of 299 species of Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae (Coleoptera). The TVB was divided into 1o × 1ogrid cells and we also included in the analysis the remaining Mexican biogeographical provinces. Parsimony analysis of endemicity with progressive character elimination (PAE‐PCE) was applied to classify areas by their shared taxa according to the most parsimonious cladograms. The nested sets of areas were represented as generalized tracks.

Results Three generalized tracks were obtained: (1) grid cells 9C, 9D, 10D, 10E, Sierra Madre Oriental, Chiapas, Mexican Gulf and the Sierra Madre del Sur; (2) grid cells 3B, 3C, 4B, 4C, 5C, 6C, 7C, Sierra Madre Occidental, Sierra Madre del Sur, Balsas Basin and the Mexican Pacific Coast, and (3) grid cells 8D, 9C, 9D, 10D, 10E, Yucatán Peninsula, Chiapas, Sierra Madre Oriental and the Mexican Gulf.

Main conclusions We conclude that the TVB does not represent a natural biogeographical unit because it shows different relationships with other biogeographical provinces, being clearly transitional between the Nearctic and Neotropical provinces. Some parts of the TVB are related to Neotropical provinces (Chiapas, Mexican Gulf and Mexican Pacific Coast) and others to the remaining provinces of the Mexican Transition Zone (Sierra Madre Oriental, Sierra Madre del Sur, Sierra Madre Occidental and Balsas Basin).
Draco, a flawless dwarf galaxy
Authors: Ségall M. , Ibata R. A. , Irwin M. J. , Martin N. F. , Chapman S.
Published: January 2007

The Draco dwarf spheroidal galaxy (dSph), with its apparent immense mass-to-light ratio and compact size, holds many clues to the nature of the enigmatic dark matter. Here we present deep photometric studies of this dwarf galaxy, undertaken with the MegaCam Camera at the Canada–France–Hawaii Telescope, the Wide Field Camera at the Isaac Newton Telescope and the Wide Field and Planetary Camera onboard the Hubble Space Telescope (HST). The new photometric data cover the entirety of the galaxy, and reach i′= 24.5 at 50 per cent completeness, significantly deeper than previous panoramic studies, allowing searches for tidal disturbances of much lower surface brightness than has been possible before. With these improved statistics, we find no evidence for asymmetric disturbances or tidal tails that possess more than 3 per cent of the stars found within the centre of the galaxy. We find that the central stellar density, as probed by the HST data, rises into the central 0.5 arcmin. Uncertainties in the position of the centroid of the galaxy do not allow us to determine whether the apparent flattening of the profile interior to 0.5 arcmin is reliable or not. Draco is therefore a flawless dwarf galaxy, featureless and apparently unaffected by Galactic tides.
Sugar feeding reduces short‐term activity of a parasitoid wasp
Authors: LEE JANA C. , HEIMPEL GEORGE E.
Published: January 2007

Abstract Adding sugar to agricultural habitats is expected to enhance pest control by improving the longevity and physiological status of parasitoids. How a sugar diet and physiological parameters affect the host‐foraging behaviour of Diadegma insulare, a parasitoid of diamondback moth larvae (Plutella xylostella), is investigated in the laboratory. Newly‐emerged females are given water or sucrose‐water ad libitum for 1 day, and then monitored for movement onto and away from a single cabbage leaf infested with 30 host larvae for 1 h. A significantly lower percentage of sucrose‐fed females enter the host patch than those with access to only water (starved) females (60% vs. 91%). Of the females that enter the patch, fed wasps spend significantly less time in the patch than starved wasps (32.2 vs. 25.7 min) but feeding does not significantly affect oviposition rate. Fed and starved females sting six to seven larvae, and 19–29% of females superparasitize host larvae. Wasps with higher levels of fructose are less likely to enter the host patch than wasps with lower fructose levels. The lower proportion of fed wasps entering the patch may be due to a period of inactivity after sugar feeding.
A gain‐of‐function allele of TPC1 activates oxylipin biogenesis after leaf wounding in Arabidopsis
Authors: Bonaventure Gustavo , Gfeller Aurélie , Proebsting William M. , Hörtensteiner Stefan , Chételat Aurore , Martinoia Enrico , Farmer Edward E.
Published: January 2007

Jasmonates, potent lipid mediators of defense gene expression in plants, are rapidly synthesized in response to wounding. These lipid mediators also stimulate their own production via a positive feedback circuit, which depends on both JA synthesis and JA signaling. To date, molecular components regulating the activation of jasmonate biogenesis and its feedback loop have been poorly characterized. We employed a genetic screen capable of detecting the misregulated activity of 13‐lipoxygenase, which operates at the entry point of the jasmonate biosynthesis pathway. Leaf extracts from the Arabidopsis fou2 (fatty acid oxygenation upregulated  2) mutant displayed an increased capacity to catalyze the synthesis of lipoxygenase (LOX) metabolites. Quantitative oxylipin analysis identified less than twofold increased jasmonate levels in healthy fou2 leaves compared to wild‐type; however, wounded fou2 leaves strongly increased jasmonate biogenesis compared to wounded wild‐type. Furthermore, the plants displayed enhanced resistance to the fungus Botrytis cinerea. Higher than wild‐type LOX activity and enhanced resistance in the fou2 mutant depend fully on a functional jasmonate response pathway. The fou2 mutant carries a missense mutation in the putative voltage sensor of the Two Pore Channel 1 gene (TPC1), which encodes a Ca2+‐permeant non‐selective cation channel. Patch‐clamp analysis of fou2 vacuolar membranes showed faster time‐dependent conductivity and activation of the mutated channel at lower membrane potentials than wild‐type. The results indicate that cation fluxes exert strong control over the positive feedback loop whereby JA stimulates its own synthesis.