bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic shear stress and heat transfer of solid hydrogen, deuterium, and neon
Authors: Leachman Jacob , Pfotenhauer John , Nellis Greg
Published: April 2012

Solidifying and solid cryogens in steady shear are of fundamental importance to the fueling of fusion energy reactors. We present steady-state measurements of the dynamic shear stress, thermal conductivity, and heat transfer during flow of solid hydrogen, deuterium, and neon in a Couette-type viscometer cell. The measurements span a range of shear rates and temperatures from the onset of solidification to sub-cooled solid states. Normalization of the shear stress with parameters of the Lennard-Jones 6–12 potential indicates a favorable prediction of tritium properties using the quantum law of corresponding states.
High-field dielectric properties and Raman spectroscopic investigation of the ferroelectric-to-relaxor crossover in BaSnxTi1−xO3 ceramics
Authors: Deluca Marco , Stoleriu Laurentiu , Curecheriu Lavinia Petronela , Horchidan Nadejda , Ianculescu Adelina Carmen , Galassi Carmen , Mitoseriu Liliana
Published: April 2012

BaSnxTi1−xO3 solid solutions with compositions in the range x = 0–0.20 were studied by combining analysis of the field-induced dielectric and ferroelectric properties with Raman spectroscopic investigations. By combining techniques, the detection of specific features related to the ferroelectric-to-relaxor crossover with increasing Sn content is possible. Detailed tunability analysis of the x = 0.05 composition indicated that multiple components contribute to the dc-field induced permittivity response; these components are active in different temperature and field ranges and could be assigned to a few polarization mechanisms. First order reversal curves (FORC) for the material clearly show a transition from ferroelectric-to-relaxor behavior with increasing x, confirming the conclusions from the Raman and dielectric studies. This was evidenced by the shift of the FORC distribution over coercivities toward zero field values. Raman measurements allow the identification of the separate phases with varying Sn content and temperature, indicating large regions of phase coexistence. The composition x = 0.20 is in a predominantly relaxor state. This is ascribed to a large range of phase coexistence and to the presence of polar nanoregions promoted by Sn substitution on the B site of the perovskite unit cell ABO3.
A systematic investigation of the ground state potential energy surface of \documentclass[12pt]{minimal}\begin{document}${\rm H}_3^+$\end{document}H3+
Authors: Jaquet Ralph , Khoma Mykhaylo V.
Published: April 2012

Based on different ab initio electronic structure calculations (CI-R12 and Gaussian Geminals) of the Born-Oppenheimer electronic energy EBO of \documentclass[12pt]{minimal}\begin{document}${\rm H}_3^+$\end{document}H3+ from high to highest quality, we build up a potential energy surface which represents a highly reliable form of the topology of the whole potential region, locally and globally. We use the CI-R12 method in order to get within reasonable CPU-time a relatively dense grid of energy points. We demonstrate that CI-R12 is good enough to give an accurate surface, i.e., Gaussian Geminals are not absolutely necessary. For different types of potential energy surface fits, we performed variational calculations of all bound vibrational states, including resonances above the dissociation limit, for total angular momentum J = 0. We clarify the differences between different fits of the energy to various functional forms of the potential surface. Small rms-values (<1 cm−1) of the fit do not provide precise information about the interpolatory behaviour of the fit functions.
Breeding lucerne for persistence
Authors: Bouton J. H.
Published: April 2012

Cultivated lucerne is the most widely grown forage legume in pastoral agriculture. Persistence is critical for most pastoral production systems and its definition includes concepts of productivity, but maintenance of adequate plant numbers is essential. There were three important eras in lucerne persistence breeding: species introduction leading to local varieties and land races (adaptation), development of multiple pest-resistant, autumn dormancy-specific cultivars, and introducing complex traits and the use of biotechnologies. Today’s persistent cultivar needs, at a minimum, adaptation, proper autumn dormancy, and targeted pest resistances. Adding complex, ‘persistence-limiting’ traits to these minimum base traits, such as tolerance to grazing, acid, aluminum-toxic soils, and drought, is successfully being achieved via traditional selection, but biotechnologies and inter-specific hybridisations are also being employed in some cases. The main issues around biotechnologies are public perception and regulatory issues which continue to hamper transgene deployment while genetic marker programs need to lower costs and concentrate on successful application. There is not one persistent ‘ideotype’ that will fill all situations, but specific ones need to be developed and targeted for geographies such as the subtropics. Finally, breeders need to understand what persistence traits lucerne producers are willing to pay a premium to obtain.
Climate change and the selective signature of the Late Ordovician mass extinction
Authors: Finnegan Seth , Heim Noel A. , Peters Shanan E. , Fischer Woodward W.
Published: April 2012

Selectivity patterns provide insights into the causes of ancient extinction events. The Late Ordovician mass extinction was related to Gondwanan glaciation; however, it is still unclear whether elevated extinction rates were attributable to record failure, habitat loss, or climatic cooling. We examined Middle Ordovician-Early Silurian North American fossil occurrences within a spatiotemporally explicit stratigraphic framework that allowed us to quantify rock record effects on a per-taxon basis and assay the interplay of macrostratigraphic and macroecological variables in determining extinction risk. Genera that had large proportions of their observed geographic ranges affected by stratigraphic truncation or environmental shifts at the end of the Katian stage were particularly hard hit. The duration of the subsequent sampling gaps had little effect on extinction risk, suggesting that this extinction pulse cannot be entirely attributed to rock record failure; rather, it was caused, in part, by habitat loss. Extinction risk at this time was also strongly influenced by the maximum paleolatitude at which a genus had previously been sampled, a macroecological trait linked to thermal tolerance. A model trained on the relationship between 16 explanatory variables and extinction patterns during the early Katian interval substantially underestimates the extinction of exclusively tropical taxa during the late Katian interval. These results indicate that glacioeustatic sea-level fall and tropical ocean cooling played important roles in the first pulse of the Late Ordovician mass extinction in Laurentia.
Pleckstrin homology domain-interacting protein (PHIP) as a marker and mediator of melanoma metastasis
Authors: De Semir David , Nosrati Mehdi , Bezrookove Vladimir , Dar Altaf A. , Federman Scot , Bienvenu Geraldine , Venna Suraj , Rangel Javier , Climent Joan , Meyer Tamgüney Tanja M. , Thummala Suresh , Tong Schuyler , Leong Stanley P. L. , Haqq Chris , Billings Paul , Miller James R. , Sagebiel Richard W. , Debs Robert , Kashani-Sabet Mohammed
Published: April 2012

Although melanomas with mutant v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) can now be effectively targeted, there is no molecular target for most melanomas expressing wild-type BRAF. Here, we show that the activation of Pleckstrin homology domain-interacting protein (PHIP), promotes melanoma metastasis, can be used to classify a subset of primary melanomas, and is a prognostic biomarker for melanoma. Systemic, plasmid-based shRNA targeting of Phip inhibited the metastatic progression of melanoma, whereas stable suppression of Phip in melanoma cell lines suppressed metastatic potential and prolonged the survival of tumor-bearing mice. The human
PHIP
gene resides on 6q14.1, and although 6q loss has been observed in melanoma, the
PHIP
locus was preserved in melanoma cell lines and patient samples, and its overexpression was an independent adverse predictor of survival in melanoma patients. In addition, a high proportion of PHIP-overexpressing melanomas harbored increased
PHIP
copy number. PHIP-overexpressing melanomas include tumors with wild-type BRAF, neuroblastoma RAS viral (v-ras) oncogene homolog, and phosphatase and tensin homolog, demonstrating PHIP activation in triple-negative melanoma. These results describe previously unreported roles for PHIP in predicting and promoting melanoma metastasis, and in the molecular classification of melanoma.
Test of a motor theory of long-term auditory memory
Authors: Schulze Katrin , Vargha-Khadem Faraneh , Mishkin Mortimer
Published: April 2012

Monkeys can easily form lasting central representations of visual and tactile stimuli, yet they seem unable to do the same with sounds. Humans, by contrast, are highly proficient in auditory long-term memory (LTM). These mnemonic differences within and between species raise the question of whether the human ability is supported in some way by speech and language, e.g., through subvocal reproduction of speech sounds and by covert verbal labeling of environmental stimuli. If so, the explanation could be that storing rapidly fluctuating acoustic signals requires assistance from the motor system, which is uniquely organized to chain-link rapid sequences. To test this hypothesis, we compared the ability of normal participants to recognize lists of stimuli that can be easily reproduced, labeled, or both (pseudowords, nonverbal sounds, and words, respectively) versus their ability to recognize a list of stimuli that can be reproduced or labeled only with great difficulty (reversed words, i.e., words played backward). Recognition scores after 5-min delays filled with articulatory-suppression tasks were relatively high (75–80% correct) for all sound types except reversed words; the latter yielded scores that were not far above chance (58% correct), even though these stimuli were discriminated nearly perfectly when presented as reversed-word pairs at short intrapair intervals. The combined results provide preliminary support for the hypothesis that participation of the oromotor system may be essential for laying down the memory of speech sounds and, indeed, that speech and auditory memory may be so critically dependent on each other that they had to coevolve.
Raising the participation age in historical perspective: policy learning from the past?
Authors: Woodin Tom , McCulloch Gary , Cowan Steven
Published: April 2012

The raising of the participation age (RPA) to 17 in 2013 and 18 in 2015 marks a historic expansion of compulsory education. Despite the tendency of New Labour governments to eschew historical understanding and explanation, RPA was conceived with the benefit of an analysis of previous attempts to extend compulsion in schooling. This paper assesses the value of a historical understanding of education policy. The period from inception to the projected implementation of RPA is an extended one which has crossed over the change of government, from Labour to Coalition, in 2010. The shifting emphases and meanings of RPA are not simply technical issues but connect to profound historical and social changes. An analysis of the history of the raising of the school leaving age reveals many points of comparison with the contemporary situation. In a number of key areas it is possible to gain insights into the ways in which the study of the past can help to comprehend the present: the role of human capital, the structures of education, in curriculum development and in terms of preparations for change.
Local vibrational modes and Fano interaction in p-type ZnO : Sb system
Authors: Samanta K , Arora A K , Katiyar R S
Published: April 2012

Local vibrational modes (LVMs) and asymmetric phonon lineshapes are investigated in ZnO : Sb system. Two LVMs at 186 and 235 cm−1 originating due to the change in reduced mass and reduction of localized interatomic force constant have been identified. Upon Sb-doping, the E1(LO) mode of ZnO was found to shift towards the lower frequency side and broaden asymmetrically. These results are analysed within the framework of the Fano interaction in p-type ZnO. Temperature dependence of the E1(LO) mode frequency and line width shows the conventional anharmonic behaviour in ZnO; whereas, it deviates in ZnO : Sb system. In addition, the carrier–phonon coupling strength was found to reduce at higher temperature.
Sharp distortion growth for bilipschitz extension of planar maps
Authors: Kovalev Leonid
Published: April 2012

This note addresses the quantitative aspect of the bilipschitz extension problem. The main result states that any bilipschitz embedding of

R

\mathbb R

into

R

2

\mathbb R^2

can be extended to a bilipschitz self-map of

R

2

\mathbb R^2

with a linear bound on the distortion.
Effect of High‐Molecular‐Weight Glutenin Subunit Allelic Composition on Wheat Flour Tortilla Quality
Authors: Jondiko Tom O. , Alviola Novie J. , Hays Dirk B. , Ibrahim Amir , Tilley Michael , Awika Joseph M.
Published: April 2012

Wheat cultivars possessing quality attributes needed to produce optimum quality tortillas have not been identified. This study investigated the effect of variations in high‐molecular‐weight glutenin subunits encoded at the Glu‐1 loci (Glu‐A1, Glu‐B1, and Glu‐D1) on dough properties and tortilla quality. Flour protein profiles, dough texture, and tortilla physical quality attributes were evaluated. Deletion at Glu‐D1 resulted in reduced insoluble polymeric protein content of flour, reduced dough compression force, and large dough extensibility. These properties produced very large tortillas (181 mm diameter) compared with a control made with commercial tortilla wheat flour (161 mm). Presence of a 7 + 9 allelic pair at Glu‐B1 increased dough strength (largest compression force, reduced extensibility, and small‐diameter tortillas). Deletion at Glu‐A1 produced large tortillas (173 mm) but with unacceptable flexibility during storage (score <3.0 at day 16). In general, presence of 2* at Glu‐A1, in combination with 5 + 10 at Glu‐D1, produced small‐diameter tortillas that required large force to rupture (tough texture). Presence of 2 + 12 alleles instead of 5 + 10 at Glu‐D1 produced tortillas with a good compromise between diameter (>165 mm) and flexibility during storage (>3.0 at day 16). These allele combinations, along with deletion at Glu‐D1, show promise for tortilla wheat development.
Dual Regulatory Roles of the Extended N Terminus for Activation of the Tomato Mi-1.2 Resistance Protein
Authors: Lukasik-Shreepaathy Ewa , Slootweg Erik , Richter Hanna , Goverse Aska , Cornelissen Ben J. C. , Takken Frank L. W.
Published: April 2012

Plant resistance (R) proteins mediate race-specific immunity and initiate host defenses that are often accompanied by a localized cell-death response. Most R proteins belong to the nucleotide binding-leucine-rich repeat (NB-LRR) protein family, as they carry a central NB-ARC domain fused to an LRR domain. The coiled-coil (CC) domain at the N terminus of some solanaceous NB-LRR proteins is extended with a solanaceae domain (SD). Tomato Mi-1.2, which confers resistance against nematodes, white flies, psyllids, and aphids, encodes a typical SD-CNL protein. Here, we analyzed the role of the extended N terminus for Mi-1.2 activation. Removal of the first part of the N terminus (Nt1) induced Mi-1.2-mediated cell death that could be suppressed by overexpression of the second half of the N-terminal region. Yet, autoactivating NB-ARC-LRR mutants require in trans coexpression of the N-terminal region to induce cell death, indicating that the N terminus functions both as a negative and as a positive regulator. Based on secondary structure predictions, we could link both activities to three distinct subdomains, a typical CC domain and two novel, structurally-conserved helical subdomains called SD1 and SD2. A negative regulatory function could be assigned to the SD1, whereas SD2 and the CC together function as positive regulators of Mi-1.2-mediated cell death.
Diagnostic Potential of Polyclonal Antibodies Against Bacterially Expressed Recombinant Coat Protein of Alfalfa mosaic virus
Authors: Khatabi B. , He B. , Hajimorad M. R.
Published: April 2012

Alfalfa mosaic virus (AMV), a pathogen of a wide range of plant species, including Glycine max (soybean), is poorly immunogenic. Polyclonal antibodies were generated against bacterially expressed recombinant coat proteins (rCPs) of two biologically distinct AMV strains in rabbits and compared with those raised against native and glutaraldehyde-treated virions of the same strains. Analyses showed that sera against rCPs had comparable antibody titers in indirect enzyme-linked immunosorbent assay with those raised against virions when soybean sap containing homologous viruses served as antigens. Polyclonal antibodies against rCPs were specific, sensitive, and detected all AMV isolates that originated from soybean fields from geographically different regions of the United States. Comparison of CP genes of these isolates showed 96 to 99 and 96 to 100% nucleotide and amino acid sequence identities, respectively, suggesting that they are all closely related. This was further confirmed by phylogenetic analysis where they were all clustered together along with representative AMV strains belonging to group I. Collectively, our data demonstrate that, despite poor immunogenicity of AMV, polyclonal antibodies against rCP are effective probes for detection and diagnosis of the virus.
Sensitivity of Phytophthora capsici on Vegetable Crops in Georgia to Mandipropamid, Dimethomorph, and Cyazofamid
Authors: Jackson K. L. , Yin J. , Ji P.
Published: April 2012

Phytophthora blight, caused by Phytophthora capsici, is a serious disease in vegetable production, and selective use of fungicides continues to be a significant component of disease management programs. The effect of three chemical compounds—mandipropamid, dimethomorph, and cyazofamid—on asexual stages of P. capsici collected from bell pepper and cucurbits in Georgia was assessed in this study. Forty isolates of P. capsici were determined to be sensitive to mandipropamid and dimethomorph based on mycelial growth, zoospore germination, and sporangial production. Concentrations that were 50% effective (EC50 values) of mandipropamid that inhibited mycelial growth, zoospore germination, and sporangial production of the isolates averaged 0.03, 5.70, and 0.02 μg/ml, respectively. EC50 values of dimethomorph in inhibiting mycelial growth, zoospore germination, and sporangial production averaged 0.24, 0.10, and 0.46 μg/ml, respectively. The majority of isolates were either resistant or intermediately sensitive to cyazofamid at 500 μg/ml or lower concentrations based on mycelial growth or sporangial production, although all the isolates were sensitive to this compound based on zoospore germination, with an average EC50 of 0.04 μg/ml. The results indicated that P. capsici populations in Georgia have not developed resistance to mandipropamid and dimethomorph whereas, for the majority of the isolates, certain asexual stages were resistant to cyazofamid.
No Indication of Strict Host Associations in a Widespread Mycoparasite: Grapevine Powdery Mildew (Erysiphe necator) Is Attacked by Phylogenetically Distant Ampelomyces Strains in the Field
Authors: Pintye Alexandra , Bereczky Zsolt , Kovács Gábor M. , Nagy László G. , Xu Xiangming , Legler Sara Elisabetta , Váczy Zsuzsanna , Váczy Kálmán Zoltán , Caffi Tito , Rossi Vittorio , Kiss Levente
Published: April 2012

Pycnidial fungi belonging to the genus Ampelomyces are common intracellular mycoparasites of powdery mildews worldwide. Some strains have already been developed as commercial biocontrol agents (BCAs) of Erysiphe necator and other powdery mildew species infecting important crops. One of the basic, and still debated, questions concerning the tritrophic relationships between host plants, powdery mildew fungi, and Ampelomyces mycoparasites is whether Ampelomyces strains isolated from certain species of the Erysiphales are narrowly specialized to their original mycohosts or are generalist mycoparasites of many powdery mildew fungi. This is also important for the use of Ampelomyces strains as BCAs. To understand this relationship, the nuclear ribosomal DNA internal transcribed spacer (ITS) and partial actin gene (act1) sequences of 55 Ampelomyces strains from E. necator were analyzed together with those of 47 strains isolated from other powdery mildew species. These phylogenetic analyses distinguished five major clades and strains from E. necator that were present in all but one clade. This work was supplemented with the selection of nine inter-simple sequence repeat (ISSR) markers for strain-specific identification of Ampelomyces mycoparasites to monitor the environmental fate of strains applied as BCAs. The genetic distances among strains calculated based on ISSR patterns have also highlighted the genetic diversity of Ampelomyces mycoparasites naturally occurring in grapevine powdery mildew. Overall, this work showed that Ampelomyces strains isolated from E. necator are genetically diverse and there is no indication of strict mycohost associations in these strains. However, these results cannot rule out a certain degree of quantitative association between at least some of the Ampelomyces lineages identified in this work and their original mycohosts.
Biology, not environment, drives major patterns in maximum tetrapod body size through time
Authors: Sookias Roland B. , Benson Roger B. J. , Butler Richard J.
Published: April 2012

Abiotic and biological factors have been hypothesized as controlling maximum body size of tetrapods and other animals through geological time. We analyse the effects of three abiotic factors—oxygen, temperature and land area—on maximum size of Permian–Jurassic archosauromorphs and therapsids, and Cenozoic mammals, using time series generalized least-squares regression models. We also examine maximum size growth curves for the Permian–Jurassic data by comparing fits of Gompertz and logistic models. When serial correlation is removed, we find no robust correlations, indicating that these environmental factors did not consistently control tetrapod maximum size. Gompertz models—i.e. exponentially decreasing rate of size increase at larger sizes—fit maximum size curves far better than logistic models. This suggests that biological limits such as reduced fecundity and niche space availability become increasingly limiting as larger sizes are reached. Environmental factors analysed may still have imposed an upper limit on tetrapod body size, but any environmentally imposed limit did not vary substantially during the intervals examined despite variation in these environmental factors.
Acute inflammatory response to cobalt chromium orthopaedic wear debris in a rodent air-pouch model
Authors: Akbar Moeed , Fraser Alasdair R. , Graham Gerard J. , Brewer James M. , Grant M. Helen
Published: April 2012

This study used a rodent air-pouch model to assess the acute inflammatory response to cobalt–chromium (CoCr) alloy wear debris from a metal-on-metal hip resurfacing implant that may contribute to joint failure. Air-pouches were injected with either sterile phosphate-buffered saline, 1 μg lipopolysaccharide (LPS) or 2.5 mg CoCr wear debris. The
in situ
inflammatory response was monitored 4, 24, 48 and 72 h and 7 days later. A flow cytometric analysis of the inflammatory exudates showed that CoCr wear debris induced a different inflammatory pattern compared with LPS. LPS induced a strong early (4 h) neutrophil influx, with monocyte/macrophage influx peaking at 24 h, whereas CoCr wear debris initiated almost equal numbers of early monocyte/macrophage and neutrophil recruitment. Histological analyses also showed CoCr debris accumulated in the pouch wall and this was accompanied by vast cellular infiltration and fibrosis around the debris throughout the duration of the experiment. Assessment of inflammatory gene transcripts from air-pouch tissue showed that CoCr wear debris increased the expression of cytokines involved in promoting inflammation and fibrosis (IL-1β, TGF-β) and chemokines that promote the recruitment of neutrophils and monocytes/macrophages (CXCL2 and CCL2). The data suggest that inflammatory responses to CoCr debris induce a specific acute process in which the recruitment of monocytes/macrophages is key.
Modes and mechanisms of aDaphniainvasion
Authors: Spaak Piet , Fox Jennifer , Hairston Nelson G.
Published: April 2012

Whether exotic species invade new habitats successfully depends on (i) a change in the invaded habitat that makes it suitable for the invader and (ii) a genetic change in the invading taxon that enhances its fitness in the new habitat, or both. We dissect the causes of invasions of Swiss lakes, north of the Alps, byDaphnia galeata(a zooplankter typical of eutrophic lakes, e.g. those south of the Alps, which are also warmer) by comparing the fitness performance of eight geographically distributed clones that were fed algal-food typical of oligotrophic versus eutrophic conditions at two temperatures.Daphnia longispina, native to oligotrophic Swiss lakes, served as a reference.Daphnia galeatarequires eutrophic food to persist, whereasD. longispinasurvives and grows on oligotrophic food but does even better on eutrophic food. Invasion byD. galeatais further explained because invading clones from the north perform better on eutrophic food and at cooler temperatures than native clones from the south, suggesting a local response to countergradient selection. Our data support the hypothesis that populations of the invader in northern lakes are dominated by well-adapted genotypes. Our results illustrate how environmental change (i.e. eutrophication) and local adaptation can act together to drive a successful invasion.
Historical pesticide applications coincided with an altered diet of aerially foraging insectivorous chimney swifts
Authors: Nocera Joseph J. , Blais Jules M. , Beresford David V. , Finity Leah K. , Grooms Christopher , Kimpe Lynda E. , Kyser Kurt , Michelutti Neal , Reudink Matthew W. , Smol John P.
Published: April 2012

Numerous environmental pressures have precipitated long-term population reductions of many insect species. Population declines in aerially foraging insectivorous birds have also been detected, but the cause remains unknown partly because of a dearth of long-term monitoring data on avian diets. Chimney swifts (Chaetura pelagica) are a model aerial insectivore to fill such information gaps because their roosting behaviour makes them easy to sample in large numbers over long time periods. We report a 48-year-long (1944–1992) dietary record for the chimney swift, determined from a well-preserved deposit of guano and egested insect remains in Ontario (Canada). This unique archive of palaeo-environmental data reflecting past chimney swift diets revealed a steep rise in dichlorodiphenyltrichloroethane (DDT) and metabolites, which were correlated with a decrease in Coleoptera remains and an increase in Hemiptera remains, indicating a significant change in chimney swift prey. We argue that DDT applications decimated Coleoptera populations and dramatically altered insect community structure by the 1960s, triggering nutritional consequences for swifts and other aerial insectivores.
Pattern of Deposition of Cell Wall Polysaccharides and Transcript Abundance of Related Cell Wall Synthesis Genes during Differentiation in Barley Endosperm
Authors: Wilson Sarah M. , Burton Rachel A. , Collins Helen M. , Doblin Monika S. , Pettolino Filomena A. , Shirley Neil , Fincher Geoffrey B. , Bacic Antony
Published: April 2012

Immunolabeling, combined with chemical analyses and transcript profiling, have provided a comprehensive temporal and spatial picture of the deposition and modification of cell wall polysaccharides during barley (Hordeum vulgare) grain development, from endosperm cellularization at 3 d after pollination (DAP) through differentiation to the mature grain at 38 DAP. (1→3)-β-d-Glucan appears transiently during cellularization but reappears in patches in the subaleurone cell walls around 20 DAP. (1→3, 1→4)-β-Glucan, the most abundant polysaccharide of the mature barley grain, accumulates throughout development. Arabino-(1-4)-β-d-xylan is deposited significantly earlier than we previously reported. This was attributable to the initial deposition of the polysaccharide in a highly substituted form that was not recognized by antibodies commonly used to detect arabino-(1-4)-β-d-xylans in sections of plant material. The epitopes needed for antibody recognition were exposed by pretreatment of sections with α-l-arabinofuranosidase; this procedure showed that arabino-(1-4)-β-d-xylans were deposited as early as 5 DAP and highlighted their changing structures during endosperm development. By 28 DAP labeling of hetero-(1→4)-β-d-mannan is observed in the walls of the starchy endosperm but not in the aleurone walls. Although absent in mature endosperm cell walls we now show that xyloglucan is present transiently from 3 until about 6 DAP and disappears by 8 DAP. Quantitative reverse transcription-polymerase chain reaction of transcripts for GLUCAN SYNTHASE-LIKE, Cellulose Synthase, and CELLULOSE SYNTHASE-LIKE genes were consistent with the patterns of polysaccharide deposition. Transcript profiling of some members from the Carbohydrate-Active Enzymes database glycosyl transferase families GT61, GT47, and GT43, previously implicated in arabino-(1-4)-β-d-xylan biosynthesis, confirms their presence during grain development.
Four NiIIcomplexes with the new cyclam–methylimidazole ligand 1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane
Authors: De Candia Ariel G. , Molnar Matias , Slep Leonardo D. , Baggio Ricardo
Published: April 2012

Although it has not proved possible to crystallize the newly prepared cyclam–methylimidazole ligand 1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane (LIm1), thetransandcisisomers of an NiIIcomplex, namelytrans-aqua{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate) monohydrate, [Ni(C15H30N6)(H2O)](ClO4)2·H2O, (1), andcis-aqua{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate), [Ni(C15H30N6)(H2O)](ClO4)2, (2), have been prepared and structurally characterized. At different stages of the crystallization and thermal treatment from which (1) and (2) were obtained, a further two compounds were isolated in crystalline form and their structures also analysed, namelytrans-{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}(perchlorato)nickel(II) perchlorate, [Ni(ClO4)(C15H30N6)]ClO4, (3), andcis-{1,8-bis[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate) 0.24-hydrate, [Ni(C20H36N6)](ClO4)2·0.24H2O, (4); the 1,8-bis[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane ligand is a minor side product, probably formed in trace amounts in the synthesis ofLIm1. The configurations of the cyclam macrocycles in the complexes have been analysed and the structures are compared with analogues from the literature.
Pioglitazone in acromegaly – an open‐label, prospective study
Authors: Kim David D. W. , Goh Jovina , Panossian Zaven , Gamble Greg , Holdaway Ian , Grey Andrew
Published: April 2012

Objective

Preclinical studies demonstrate that thiazolidinediones (TZDs) decrease growth hormone (GH) and insulin‐like growth factor‐1 (IGF‐1) levels, suggesting that they might be effective treatments for acromegaly. This study investigated the effect of pioglitazone on biochemical indices of disease activity in acromegaly.

Design and participants

This was a 4‐month open‐label prospective study in 16 patients with active acromegaly who were attending public hospital endocrinology clinics.

Methods

The intervention was pioglitazone 45 mg/day. The primary outcome was change in serum IGF‐1; the secondary outcome was change in area under the curve of glucose‐suppressed GH.

Results

Serum IGF‐1 did not change during treatment with pioglitazone (P = 0·95). After 4 months, the mean (95% CI) change from baseline was −1 μg/l (−51, 49). GH levels following oral glucose loading were unchanged during pioglitazone therapy. After 4 months, the mean (95% CI) change from baseline in area under curve for glucose‐suppressed GH was 31 μg/l (−75, 138, P = 0·54).

Conclusions

Short‐term treatment with conventional doses of pioglitazone did not improve biochemical measures of disease activity in acromegaly.
The demographic impacts of shifts in climate means and extremes on alpine butterflies
Authors: Buckley Lauren B. , Kingsolver Joel G.
Published: April 2012

1. Climate change impacts organismal performance via both shifts in mean conditions and acute thermal stress events. Yet, we know little about the relative fitness impacts of climate means and extremes, and how phenotypes mediate these effects.

2. Here, we incorporate demography in a biophysical model of two alpine butterflies with distinct phenotypes to examine the impacts of recent climate change in the Rocky Mountains of Colorado.

3. The model suggests that shifts in available flight time (mediated by weather means) and egg viability (mediated by weather extremes) over time have varied between phenotypes and along the elevation gradient. Generally, small declines in egg viability may be more than offset by large increases in available flight time at higher elevations.

4. Interactions between environmental conditions and phenotypes may produce unexpected, individualistic responses to climate change.
Net ecosystem exchange modifies the relationship between the autotrophic and heterotrophic components of soil respiration with abiotic factors in prairie grasslands
Authors: Gomez‐Casanovas Nuria , Matamala Roser , Cook David R. , Gonzalez‐Meler Miquel A.
Published: April 2012

We investigated the relationships of net ecosystem carbon exchange (NEE), soil temperature, and moisture with soil respiration rate and its components at a grassland ecosystem. Stable carbon isotopes were used to separate soil respiration into autotrophic and heterotrophic components within an eddy covariance footprint during the 2008 and 2009 growing seasons. After correction for self‐correlation, rates of soil respiration and its autotrophic and heterotrophic components for both years were found to be strongly influenced by variations in daytime NEE – the amount of C retained in the ecosystem during the daytime, as derived from NEE measurements when photosynthetically active radiation was above 0 μmol m−2 s−1. The time scale for correlation of variations in daytime NEE with fluctuations in respiration was longer for heterotrophic respiration (36–42 days) than for autotrophic respiration (4–6 days). In addition to daytime NEE, autotrophic respiration was also sensitive to soil moisture but not soil temperature. In contrast, heterotrophic respiration from soils was sensitive to changes in soil temperature, soil moisture, and daytime NEE. Our results show that – as for forests – plant activity is an important driver of both components of soil respiration in this tallgrass prairie grassland ecosystem. Heterotrophic respiration had a slower coupling with plant activity than did autotrophic respiration. Our findings suggest that the frequently observed variations in the sensitivity of soil respiration to temperature or moisture may stem from variations in the proportions of autotrophic and heterotrophic components of soil respiration. Rates of photosynthesis at seasonal time scales should also be considered as a driver of both autotrophic and heterotrophic soil respiration for ecosystem flux modeling.
Resource concentration by insects and implications for plant populations
Authors: Stephens Andrea E. A. , Myers Judith H.
Published: April 2012

1. The distribution of herbivores among plant patches may be an important factor determining plant population persistence. The resource concentration hypothesis proposes that herbivores are more abundant per unit plant at higher host plant densities and this has been found to occur in many systems. However, the opposite pattern, resource dilution, in which the herbivores are more abundant in low‐density patches and situations in which the number of insect herbivores per unit plant remains constant, also occurs.

2. We developed a simulation model to explore how the distribution of insects per plant affects plant population decline and persistence. We varied the numbers of plants per patch and the distribution pattern, i.e. whether insects were found in a resource concentration distribution, a resource dilution distribution or a distribution in which insect abundance increased linearly with plant density.

3. Resource concentration resulted in longer persistence of plant populations. Plant populations declined more rapidly with either weak resource dilution or directly proportional insect distribution patterns. As the intensity of resource concentration increased, the decline in plant population density was reduced, and plant persistence increased because of increasing variance in insect load. Under strong resource dilution, increasing variance in the insect load also led to a reduction in plant population decline and an increase in plant persistence.

4. We complement our model with field data from the diffuse knapweed, Centaurea diffusa biocontrol system. We compared the relationship with plant density of a successful biocontrol agent, Larinus minutus, and an unsuccessful one, Urophora affinis. Larinus minutus density was directly proportional to plant density, while U. affinis showed a resource concentration pattern with higher rates of attack in high‐density patches.

5. Synthesis: Patterns of insect distribution with host plant density will alter the extent to which patches of differing plant densities decline or persist. Resource concentration promotes persistence of the insect–plant system because increased herbivore pressure in high‐density patches leads to negative density‐dependent plant growth. Weak resource dilution and a distribution of insects that is directly proportionate to plant density can accelerate plant population decline. Strong resource dilution leads to positive density dependence with higher population growth in large patches. Our simulation model and field data demonstrate that the relationship between insect distribution and plant densities can influence plant population dynamics and has implications for choices of weed biological control agents.
Topography of descending projections from anterior insular and medial prefrontal regions to the lateral habenula of the epithalamus in the rat
Authors: Kim Uhnoh , Lee Taehee
Published: April 2012

The epithalamic lateral nucleus of the habenula (LHb) plays a key role in regulating firing of dopamine and serotonin neurons in the midbrain and is thereby involved in various cognitive and affective behaviors. It is not yet clear, however, from where the LHb receives cognitive and affective information relevant to its regulation of the midbrain monoaminergic systems. The prefrontal cortex would be among the ideal sources. Here, using anterograde and retrograde tracer injections in the rat brain, we characterized the topography of the corticohabenular projections. Following injections of cholera toxin subunit B into the LHb, retrogradely labeled neurons were produced in the anterior insular, cingulate, prelimbic and infralimbic cortices. Consistent with this retrograde tracing, injections of biotinylated dextran amine (BDA) into these cortical regions labeled robust terminals in the LHb. Our quantification of the BDA‐impregnated varicosities revealed that projections from the anterior insula terminated mainly in the intersection regions of the lateral and ventral two‐thirds of the LHb, while projections from the cingulate cortex terminated mainly in the lateral two‐thirds of the LHb. By comparison, BDA‐labeled terminals originating from the medial prefrontal regions were contained mainly in the medial plus ventral one‐third of LHb. Based on these data, we hypothesize that LHb provides a link for conveying cognitive and affective information from prefrontal and insular regions to the midbrain monoaminergic centers.
Different stressors produce excitation or inhibition of mesolimbic dopamine neuron activity: response alteration by stress pre‐exposure
Authors: Valenti Ornella , Gill Kathryn M. , Grace Anthony A.
Published: April 2012

Stressors can exert a wide variety of responses, ranging from adaptive responses to pathological changes; moreover, recent studies suggest that mild stressors can attenuate the response of a system to major stressful events. We have previously shown that 2‐week exposure to cold, a comparatively mild inescapable stressor, induced a pronounced reduction in ventral tegmental area (VTA) dopamine (DA) neuron activity, whereas restraint stress increases DA neuron activity. However, it is not known if these stressors differentially impact the VTA in a region‐specific manner, if they differentially impact behavioral responses, or whether the effects of such different stressors are additive or antagonistic with regard to their impact on DA neuron firing. To address these questions, single‐unit extracellular recordings were performed in anesthetized control rats and rats exposed to chronic cold, and tested after delivery of a 2‐h restraint session. Chronic cold stress strongly attenuated the number of DA neurons firing in the VTA, and this effect occurred primarily in the medial and central VTA regions that preferentially project to reward‐related ventral striatal regions. Chronic cold exposure also prevented the pronounced increase in DA neuron population activity without affecting the behavioral sensitization to amphetamine produced by restraint stress. Taken together, these data show that a prolonged inescapable mild stressor can induce plastic changes that attenuate the DA system response to acute stress.
Nauseating Flux: Iris Murdoch on Sartre and Heraclitus
Authors: Robjant David
Published: April 2012

I observe Iris Murdoch's distinctive use of the word ‘flux’ in discussion of Sartre's Nausea and show that her usage is persuasive and revolutionary, first as Sartre exegesis, second as Heraclitus exegesis, and throughout as a contribution to the philosophy of language. Murdoch's usage of ‘flux’ frames a comparison of Sartre's Roquentin with other figures who have had similarly flowing experience but without nausea. Roquentin's plight is shown to be ‘a philosopher's plight’ precipitated by a defective theory of descriptive success. I then show how the Heraclitean fragments would support Murdoch's treatment of flux and on close analysis contradict the established view exemplified in the work of Wittgenstein and Jonathan Barnes. Flux is not a variety of change, and the river image ‘cannot be analysed into non‐metaphorical components without a loss of substance’.
Topical corticosteroids in plaque psoriasis: a systematic review of risk of adrenal axis suppression and skin atrophy
Authors: Castela E. , Archier E. , Devaux S. , Gallini A. , Aractingi S. , Cribier B. , Jullien D. , Aubin F. , Bachelez H. , Joly P. , Le Maître M. , Misery L. , Richard M.‐A. , Paul C. , Ortonne J.P.
Published: April 2012

Background  Topical steroids have been used for more than 50 years in mild‐to‐moderate plaque psoriasis and carry a theoretical risk of adverse events.

Objectives The aim of this systematic literature review was to evaluate the risk of hypothalamo‐pituitary‐adrenal (HPA) axis suppression and the risk of skin atrophy with topical steroids in the treatment of plaque psoriasis.

Methods A systematic search between 1980 and January 2011 in Medline, Embase and Cochrane databases (English, French language, adults), using the keywords ‘psoriasis’/exp/mj AND ‘corticosteroid’/exp/mj,

Results  Altogether 1269 references were found. Of these 1124 articles were excluded by reading the abstract and 123 by reading the article. A total of 22 randomized trials were selected.

Effects on HPA axis: Thirteen studies, with a sample size varying from 7 to 341 patients, were selected. The effect on HPA axis was evaluated by the morning cortisol level (11 studies), the 24 h urine steroid levels (five studies) and/or by the Synacthen® test (three studies). Reduction of morning cortisol was observed in 0–25% of patients in 10 short‐term studies (two in scalp psoriasis, eight in body psoriasis) and in 48% of patients in the remaining short‐term study (body psoriasis). Only four of these studies with three on body psoriasis evaluated the effect of long‐term treatment defined as 6‐month treatment duration or longer and did not identify HPA axis suppression by cortisol level measurement. The Synacthen® test, considered as the gold standard to assess HPA axis, was always normal. There was no evidence of clinically significant HPA axis suppression due to absorption of topical steroids even when treating the scalp or in patients with extensive disease.

Risk of skin atrophy: Thirteen studies with topical steroid evaluating treatment durations from 4 weeks to 1 year were analysed. The frequency of skin atrophy assessed clinically, varied from 0% to 5% of patients.

Conclusions  The literature analysis on topical steroids in psoriasis is reassuring although the quality of safety studies is limited with a majority of short‐term studies. Although short‐term biological effects of topical steroids on the HPA axis were observed in several clinical studies, they were not associated with clinical signs. Adequately designed long‐term studies would be necessary to better determine the risk of skin atrophy using modern methods of evaluation such as dermoscopy and echography.
Topical vitamin D analogues alone or in association with topical steroids for psoriasis: a systematic review
Authors: Devaux S , Castela A. , Archier E , Gallini A , Joly P. , Misery L. , Aractingi S. , Aubin F. , Bachelez H. , Cribier B. , Jullien D. , Le Maître M. , Richard M.‐A. , Ortonne J.‐P. , Paul C.
Published: April 2012

Objective  The objective of this systematic review was to prepare for evidence‐based recommendations on the use of vitamin D analogues, and their combination with topical steroids in psoriasis.

Methods  Literature systematic review performed in May 2011. The Cochrane, PubMed and Embase databases were systematically searched with different combinations: including Psoriasis AND calcipotriol expanded to all vitamin D analogues. To assess efficacy across studies, we used two predefined criteria to account for the numerous endpoints found in the literature, ‘Treatment success’ corresponding to 90% improvement in severity and ‘Satisfactory response’ corresponding to 75% improvement. We conducted a meta‐analysis comparing the efficacy of vitamin D analogues plus topical steroids (VDS) vs. vitamin D analogues alone (VD). To determine the relative cost‐efficacy of the topical drugs available on the market, cost/efficacy ratios were calculated for each product according to the approved therapeutic regimen.

Results  51 articles were selected. The application duration varied between three to 52 weeks across studies. VD as monotherapy had a satisfactory response rate between 22% to 96% and a treatment success rate ranging from 4% to 40%. VDS had a satisfactory response rate between 35% to 86% and a treatment success rate ranging from 27% to 53%. A meta‐analysis found a probability of success twice higher with VDS than with VD in adult plaque psoriasis. The cost/efficacy ratio was evaluated as 1.2–1.8 times higher for VDS than for VD.

Conclusion  VDS is twice more effective than VD and displays a better cost per success. Additional studies are needed to clarify maintenance treatment, impact on quality of life, treatment of non‐plaque psoriasis. It will be important to harmonize outcome measures in future studies with topical agents in psoriasis to better appraise their efficacy.