207 research outputs found
Phase stability of lanthanum orthovanadate at high-pressure
When monoclinic monazite-type LaVO4 (space group P21/n) is squeezed up to 12
GPa at room temperature, a phase transition to another monoclinic phase has
been found. The structure of the high-pressure phase of LaVO4 is indexed with
the same space group (P21/n), but with a larger unit-cell in which the number
of atoms is doubled. The transition leads to an 8% increase in the density of
LaVO4. The occurrence of such a transition has been determined by x-ray
diffraction, Raman spectroscopy, and ab initio calculations. The combination of
the three techniques allows us to also characterize accurately the pressure
evolution of unit-cell parameters and the Raman (and IR)-active phonons of the
low- and high-pressure phase. In particular, room-temperature equations of
state have been determined. The changes driven by pressure in the crystal
structure induce sharp modifications in the color of LaVO4 crystals, suggesting
that behind the monoclinic-to-monoclinic transition there are important changes
of the electronic properties of LaVO4.Comment: 39 pages, 6 tables, 7 figure
Sustainable Pavement Management. Integrating Economic, Technical, and Environmental Aspects in Decision Making
Sustainability, which is founded in the reconciliation of economic, environmental and social aspects, has become a major issue for infrastructure managers. The economic and environmental impacts of pavement maintenance are not negligible. More than 400 billion USD are invested globally each year in pavement construction and maintenance. These tasks increase the environmental impacts of vehicle operation by 10%. Because maintenance should be technically appropriate, it is important to integrate technical, economic and environmental aspects in the evaluation of maintenance alternatives over the life cycle of pavement. However, these aspects are normally assessed in different units that are difficult to combine in the decision-making process.
This research examines and compares different methods for the integrated consideration of technical, economic and environmental aspects. This study aims to assist highway agencies, researchers and practitioners with the integration of these aspects for the sustainable management of pavement. For this purpose, a set of maintenance alternatives for asphalt pavements are evaluated. Different methods for the integration of these aspects are explored, leading to recommendations for the most suitable methods for different scenarios. Because of this analysis, the Analytic Hierarchy Process (AHP) is recommended when the number of alternatives is reduced. In these situations, the AHP leads to results that are similar to those of the Weighting Sum and Multi-Attribute approaches that are frequently used for intuitive selection. However, when the number of alternatives is large, pair comparison becomes difficult when using the AHP and the Weighting Sum method becomes more appropriate.The authors gratefully acknowledge the scholarship awarded by the Vicerrectoria de Investigacion from the Pontificia Universidad Catolica de Chile and funded by the Ministerio de Educacion de Chile. The research team acknowledges FONDEF-Comision Nacional de Investigacion Cientifica y Technologica (CONICYT) 2009 for funding the project Research and Development of Solutions for Urban Pavement Management in Chile. In addition, the authors sincerely appreciate the funding provided by CONICYT and the National Research Center for Integrated Natural Disaster Management.Torres MachĂ, C.; Chamorro, A.; Pellicer Armiñana, E.; Yepes, V.; Videla, C. (2015). Sustainable Pavement Management. Integrating Economic, Technical, and Environmental Aspects in Decision Making. Transportation Research Record. 2523:56-63. doi:10.3141/2523-07S56632523Chester, M. V., & Horvath, A. (2009). Environmental assessment of passenger transportation should include infrastructure and supply chains. Environmental Research Letters, 4(2), 024008. doi:10.1088/1748-9326/4/2/024008Chamorro, A., & Tighe, S. L. (2009). Development of a Management Framework for Rural Roads in Developing Countries. Transportation Research Record: Journal of the Transportation Research Board, 2093(1), 99-107. doi:10.3141/2093-12Torres-Machi, C., Chamorro, A., Yepes, V., & Pellicer, E. (2014). Current models and practices of economic and environmental evaluation for sustainable network-level pavement management. Revista de la construcciĂłn, 13(2), 49-56. doi:10.4067/s0718-915x2014000200006Haas, R., Tighe, S. L., & Falls, L. C. (2006). Determining Return on Long-Life Pavement Investments. Transportation Research Record: Journal of the Transportation Research Board, 1974(1), 10-17. doi:10.1177/0361198106197400102Wu, Z., Flintsch, G., Ferreira, A., & Picado-Santos, L. de. (2012). Framework for Multiobjective Optimization of Physical Highway Assets Investments. Journal of Transportation Engineering, 138(12), 1411-1421. doi:10.1061/(asce)te.1943-5436.0000458Wu, Z., & Flintsch, G. W. (2009). Pavement Preservation Optimization Considering Multiple Objectives and Budget Variability. Journal of Transportation Engineering, 135(5), 305-315. doi:10.1061/(asce)te.1943-5436.0000006Cafiso, S., Di Graziano, A., Kerali, H. R., & Odoki, J. B. (2002). Multicriteria Analysis Method for Pavement Maintenance Management. Transportation Research Record: Journal of the Transportation Research Board, 1816(1), 73-84. doi:10.3141/1816-09Giustozzi, F., Crispino, M., & Flintsch, G. (2012). Multi-attribute life cycle assessment of preventive maintenance treatments on road pavements for achieving environmental sustainability. The International Journal of Life Cycle Assessment, 17(4), 409-419. doi:10.1007/s11367-011-0375-6Nathman, R., McNeil, S., & Van Dam, T. J. (2009). Integrating Environmental Perspectives into Pavement Management. Transportation Research Record: Journal of the Transportation Research Board, 2093(1), 40-49. doi:10.3141/2093-05Robinette, C., & Epps, J. (2010). Energy, Emissions, Material Conservation, and Prices Associated with Construction, Rehabilitation, and Material Alternatives for Flexible Pavement. Transportation Research Record: Journal of the Transportation Research Board, 2179(1), 10-22. doi:10.3141/2179-02Osorio, A., Chamorro, A., Tighe, S., & Videla, C. (2014). Calibration and Validation of Condition Indicator for Managing Urban Pavement Networks. Transportation Research Record: Journal of the Transportation Research Board, 2455(1), 28-36. doi:10.3141/2455-04Saaty, T. L. (1990). How to make a decision: The analytic hierarchy process. European Journal of Operational Research, 48(1), 9-26. doi:10.1016/0377-2217(90)90057-
Angle-resolved photoemission study and first principles calculation of the electronic structure of GaTe
The electronic band structure of GaTe has been calculated by numerical atomic
orbitals density-functional theory, in the local density approximation. In
addition, the valence-band dispersion along various directions of the GaTe
Brillouin zone has been determined experimentally by angle-resolved
photoelectron spectroscopy. Along these directions, the calculated valence-band
structure is in good concordance with the valence-band dispersion obtained by
these measurements. It has been established that GaTe is a direct-gap
semiconductor with the band gap located at the Z point, that is, at Brillouin
zone border in the direction perpendicular to the layers. The valence-band
maximum shows a marked \textit{p}-like behavior, with a pronounced anion
contribution. The conduction band minimum arises from states with a comparable
\textit{s}- \textit{p}-cation and \textit{p}-anion orbital contribution.
Spin-orbit interaction appears to specially alter dispersion and binding energy
of states of the topmost valence bands lying at . By spin-orbit, it is
favored hybridization of the topmost \textit{p}-valence band with deeper
and flatter \textit{p}-\textit{p} bands and the valence-band minimum at
is raised towards the Fermi level since it appears to be determined by
the shifted up \textit{p}-\textit{p} bands.Comment: 7 text pages, 6 eps figures, submitted to PR
In Depth Characterization of Repetitive DNA in 23 Plant Genomes Reveals Sources of Genome Size Variation in the Legume Tribe Fabeae
The differential accumulation and elimination of repetitive DNA are key drivers of genome size variation in flowering plants, yet there have been few studies which have analysed how different types of repeats in related species contribute to genome size evolution within a phylogenetic context. This question is addressed here by conducting large-scale comparative analysis of repeats in 23 species from four genera of the monophyletic legume tribe Fabeae, representing a 7.6-fold variation in genome size. Phylogenetic analysis and genome size reconstruction revealed that this diversity arose from genome size expansions and contractions in different lineages during the evolution of Fabeae. Employing a combination of low-pass genome sequencing with novel bioinformatic approaches resulted in identification and quantification of repeats making up 55-83% of the investigated genomes. In turn, this enabled an analysis of how each major repeat type contributed to the genome size variation encountered. Differential accumulation of repetitive DNA was found to account for 85% of the genome size differences between the species, and most (57%) of this variation was found to be driven by a single lineage of Ty3/gypsy LTR-retrotransposons, the Ogre elements. Although the amounts of several other lineages of LTR-retrotransposons and the total amount of satellite DNA were also positively correlated with genome size, their contributions to genome size variation were much smaller (up to 6%). Repeat analysis within a phylogenetic framework also revealed profound differences in the extent of sequence conservation between different repeat types across Fabeae. In addition to these findings, the study has provided a proof of concept for the approach combining recent developments in sequencing and bioinformatics to perform comparative analyses of repetitive DNAs in a large number of non-model species without the need to assemble their genomes
New polymorph of InVO4: A high-pressure structure with six-coordinated vanadium
This document is the unedited Authorâs version of a Submitted Work that was subsequently accepted for publication in Inorganic Chemestry, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/ic402043xA new wolframite-type polymorph of InVO4 is identified under compression near 7 GPa by in situ high-pressure (HP) X-ray diffraction (XRD) and Raman spectroscopic investigations on the stable orthorhombic InVO4. The structural transition is accompanied by a large volume collapse (Delta V/V = -14%) and a drastic increase in bulk modulus (from 69 to 168 GPa). Both techniques also show the existence of a third phase coexisting with the low- and high-pressure phases in a limited pressure range close to the transition pressure. XRD studies revealed a highly anisotropic compression in orthorhombic InVO4. In addition, the compressibility becomes nonlinear in the HP polymorph. The volume collapse in the lattice is related to an increase of the polyhedral coordination around the vanadium atoms. The transformation is not fully reversible. The drastic change in the polyhedral arrangement observed at the transition is indicative of a reconstructive phase transformation. The HP phase here found is the only modification of InVO4 reported to date with 6-fold coordinated vanadium atoms. Finally, Raman frequencies and pressure coefficients in the low- and high-pressure phases of InVO4 are reported.This research supported by the Spanish government MINECO under Grant Nos. MAT2010-21270-C04-01/04 and CSD2007-00045. O.G. acknowledges support from Vicerrectorado de Investigacion y Desarrollo of UPV (Grant No. UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11). S.N.A. acknowledges support provided by Universitat de Valencia during his visit to it. B.G.-D. acknowledges the financial support from MINECO through the FPI program.Errandonea, D.; Gomis Hilario, O.; GarcĂa-Domene, B.; Pellicer Porres, J.; Katari, V.; Achary, SN.; Tyagi, AK.... (2013). New polymorph of InVO4: A high-pressure structure with six-coordinated vanadium. Inorganic Chemistry. 52(21):12790-12798. https://doi.org/10.1021/ic402043xS1279012798522
Genomic Diversity in Two Related Plant Species with and without Sex Chromosomes - Silene latifolia and S. vulgaris
Genome size evolution is a complex process influenced by polyploidization, satellite DNA accumulation, and expansion of retroelements. How this process could be affected by different reproductive strategies is still poorly understood.We analyzed differences in the number and distribution of major repetitive DNA elements in two closely related species, Silene latifolia and S. vulgaris. Both species are diploid and possess the same chromosome number (2nâ=â24), but differ in their genome size and mode of reproduction. The dioecious S. latifolia (1Câ=â2.70 pg DNA) possesses sex chromosomes and its genome is 2.5Ă larger than that of the gynodioecious S. vulgaris (1Câ=â1.13 pg DNA), which does not possess sex chromosomes. We discovered that the genome of S. latifolia is larger mainly due to the expansion of Ogre retrotransposons. Surprisingly, the centromeric STAR-C and TR1 tandem repeats were found to be more abundant in S. vulgaris, the species with the smaller genome. We further examined the distribution of major repetitive sequences in related species in the Caryophyllaceae family. The results of FISH (fluorescence in situ hybridization) on mitotic chromosomes with the Retand element indicate that large rearrangements occurred during the evolution of the Caryophyllaceae family.Our data demonstrate that the evolution of genome size in the genus Silene is accompanied by the expansion of different repetitive elements with specific patterns in the dioecious species possessing the sex chromosomes
The CCG-domain-containing subunit SdhE of succinate:quinone oxidoreductase from Sulfolobus solfataricus P2 binds a [4Feâ4S] cluster
In type E succinate:quinone reductase (SQR), subunit SdhE (formerly SdhC) is thought to function as monotopic membrane anchor of the enzyme. SdhE contains two copies of a cysteine-rich sequence motif (CXnCCGXmCXXC), designated as the CCG domain in the Pfam database and conserved in many proteins. On the basis of the spectroscopic characterization of heterologously produced SdhE from Sulfolobus tokodaii, the protein was proposed in a previous study to contain a labile [2Feâ2S] cluster ligated by cysteine residues of the CCG domains. Using UV/vis, electron paramagnetic resonance (EPR), 57Fe electronânuclear double resonance (ENDOR) and Mössbauer spectroscopies, we show that after an in vitro cluster reconstitution, SdhE from S. solfataricus P2 contains a [4Feâ4S] cluster in reduced (2+) and oxidized (3+) states. The reduced form of the [4Feâ4S]2+ cluster is diamagnetic. The individual iron sites of the reduced cluster are noticeably heterogeneous and show partial valence localization, which is particularly strong for one unique ferrous site. In contrast, the paramagnetic form of the cluster exhibits a characteristic rhombic EPR signal with gzyx = 2.015, 2.008, and 1.947. This EPR signal is reminiscent of a signal observed previously in intact SQR from S. tokodaii with gzyx = 2.016, 2.00, and 1.957. In addition, zinc K-edge X-ray absorption spectroscopy indicated the presence of an isolated zinc site with an S3(O/N)1 coordination in reconstituted SdhE. Since cysteine residues in SdhE are restricted to the two CCG domains, we conclude that these domains provide the ligands to both the ironâsulfur cluster and the zinc site
The CONSTANCES cohort: an open epidemiological laboratory
<p>Abstract</p> <p>Background</p> <p>Prospective cohorts represent an essential design for epidemiological studies and allow for the study of the combined effects of lifestyle, environment, genetic predisposition, and other risk factors on a large variety of disease endpoints. The CONSTANCES cohort is intended to provide public health information and to serve as an "open epidemiologic laboratory" accessible to the epidemiologic research community. Although designed as a "general-purpose" cohort with very broad coverage, it will particularly focus on occupational and social determinants of health, and on aging.</p> <p>Methods/Design</p> <p>The CONSTANCES cohort is designed as a randomly selected representative sample of French adults aged 18-69 years at inception; 200,000 subjects will be included over a five-year period. At inclusion, the selected subjects will be invited to fill a questionnaire and to attend a Health Screening Center (HSC) for a comprehensive health examination: weight, height, blood pressure, electrocardiogram, vision, auditory, spirometry, and biological parameters; for those aged 45 years and older, a specific work-up of functional, physical, and cognitive capacities will be performed. A biobank will be set up. The follow-up includes a yearly self-administered questionnaire, and a periodic visit to an HSC. Social and work-related events and health data will be collected from the French national retirement, health and death databases. The data that will be collected include social and demographic characteristics, socioeconomic status, life events, behaviors, and occupational factors. The health data will cover a wide spectrum: self-reported health scales, reported prevalent and incident diseases, long-term chronic diseases and hospitalizations, sick-leaves, handicaps, limitations, disabilities and injuries, healthcare utilization and services provided, and causes of death.</p> <p>To take into account non-participation at inclusion and attrition throughout the longitudinal follow-up, a cohort of non-participants will be set up and followed through the same national databases as participants.</p> <p>A field-pilot was performed in 2010 in seven HSCs, which included about 3,500 subjects; it showed a satisfactory structure of the sample and a good validity of the collected data.</p> <p>Discussion</p> <p>The constitution of the full eligible sample is planned during the last trimester of 2010, and the cohort will be launched at the beginning of 2011.</p
Antitumor effect of sFlt-1 gene therapy system mediated by Bifidobacterium Infantis on Lewis lung cancer in mice
Soluble fms-like tyrosine kinase receptor (sFlt-1) is a soluble form of extramembrane part of vascular endothelial growth factor receptor-1 (VEGFR-1) that has antitumor effects. Bifidobacterium Infantis is a kind of non-pathogenic and anaerobic bacteria that may have specific targeting property of hypoxic environment inside of solid tumors. The aim of this study was to construct Bifidobacterium Infantis-mediated sFlt-1 gene transferring system and investigate its antitumor effect on Lewis lung cancer (LLC) in mice. Our results demonstrated that the Bifidobacterium Infantis-mediated sFlt-1 gene transferring system was constructed successfully and the system could express sFlt-1 at the levels of gene and protein. This system could not only significantly inhibit growth of human umbilical vein endothelial cells induced by VEGF in vitro, but also inhibit the tumor growth and prolong survival time of LLC C57BL/6 mice safely. These data suggest that Bifidobacterium Infantis-mediated sFlt-1 gene transferring system presents a promising therapeutic approach for the treatment of cancer
Roflumilast in moderate-to-severe chronic obstructive pulmonary disease treated with longacting bronchodilators: two randomised clinical trials
Background Patients with chronic obstructive pulmonary disease (COPD) have few options for treatment. The efficacy and safety of the phosphodiesterase-4 inhibitor roflumilast have been investigated in studies of patients with moderate-to-severe COPD, but not in those concomitantly treated with longacting inhaled bronchodilators. The effect of roflumilast on lung function in patients with COPD that is moderate to severe who are already being treated with salmeterol or tiotropium was investigated. Methods In two double-blind, multicentre studies done in an outpatient setting, after a 4-week run-in, patients older than 40 years with moderate-to-severe COPD were randomly assigned to oral roflumilast 500 mu g or placebo once a day for 24 weeks, in addition to salmeterol (M2-127 study) or tiotropium (M2-128 study). The primary endpoint was change in prebronchodilator forced expiratory volume in 1s (FEV(1)). Analysis was by intention to treat. The studies are registered with ClinicalTrials.gov, number NCT00313209 for M2-127, and NCT00424268 for M2-128. Findings In the salmeterol plus roflumilast trial, 466 patients were assigned to and treated with roflumilast and 467 with placebo; in the tiotropium plus roflumilast trial, 371 patients were assigned to and treated with roflumilast and 372 with placebo. Compared with placebo, roflumilast consistently improved mean prebronchodilator FEV(1) by 49 mL (p<0.0001) in patients treated with salmeterol, and 80 mL (p<0.0001) in those treated with tiotropium. Similar improvement in postbronchodilator FEV(1) was noted in both groups. Furthermore, roflumilast had beneficial effects on other lung function measurements and on selected patient-reported outcomes in both groups. Nausea, diarrhoea, weight loss, and, to a lesser extent, headache were more frequent in patients in the roflumilast groups. These adverse events were associated with increased patient withdrawal. Interpretation Roflumilast improves lung function in patients with COPD treated with salmeterol or tiotropium, and could become an important treatment for these patients
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