984 resultados para Eliot, Andrew--1718-1778
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There is an urgent need to make drug discovery cheaper and faster. This will enable the development of treatments for diseases currently neglected for economic reasons, such as tropical and orphan diseases, and generally increase the supply of new drugs. Here, we report the Robot Scientist 'Eve' designed to make drug discovery more economical. A Robot Scientist is a laboratory automation system that uses artificial intelligence (AI) techniques to discover scientific knowledge through cycles of experimentation. Eve integrates and automates library-screening, hit-confirmation, and lead generation through cycles of quantitative structure activity relationship learning and testing. Using econometric modelling we demonstrate that the use of AI to select compounds economically outperforms standard drug screening. For further efficiency Eve uses a standardized form of assay to compute Boolean functions of compound properties. These assays can be quickly and cheaply engineered using synthetic biology, enabling more targets to be assayed for a given budget. Eve has repositioned several drugs against specific targets in parasites that cause tropical diseases. One validated discovery is that the anti-cancer compound TNP-470 is a potent inhibitor of dihydrofolate reductase from the malaria-causing parasite Plasmodium vivax.
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Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the (15)N:(14)N ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil. In both hot ecosystems and dry ecosystems, soil organic matter was more enriched in (15)N than in corresponding cold ecosystems or wet ecosystems. Below a MAT of 9.8°C, soil δ(15)N was invariant with MAT. At the global scale, soil organic C concentrations also declined with increasing MAT and decreasing MAP. After standardizing for variation among mineral soils in soil C and clay concentrations, soil δ(15)N showed no consistent trends across global climate and latitudinal gradients. Our analyses could place new constraints on interpretations of patterns of ecosystem N cycling and global budgets of gaseous N loss.
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The Structural Genomics Consortium (SGC) and its clinical, industry and disease-foundation partners are launching open-source preclinical translational medicine studies.
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Universidade Estadual de Campinas. Faculdade de Educação Física
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O objetivo deste trabalho foi estudar as características da carcaça de suínos de diferentes linhagens genéticas, em diferentes idades ao abate. Foram utilizados 88 suínos por linhagem, fêmeas e machos castrados, com idade e peso médio iniciais de 74 dias e 30kg, respectivamente, pertencentes a três linhagens genéticas distintas, designadas de AgroceresPic, Dalland e Seghers. A etapa experimental foi dividida em quatro fases (Crescimento I, Crescimento II, Terminação I e Terminação II). Ao final de cada etapa, foram abatidos 60 animais (10 por linhagem/sexo), para as caracterizações: Peso (PCQ) e Rendimento de Carcaça Quente (RCQ), Área de Olho de Lombo (AOL) e Espessura de Toucinho (ET). Na análise dos resultados foi utilizado um delineamento inteiramente casualizado com desdobramento dos graus de liberdade em esquema fatorial 4 x 3 x 2, sendo quatro idades ao abate (90, 119, 150 e 186 dias), três linhagens (AgroceresPic, Dalland e Seghers) e dois sexos (fêmea e macho castrado), com 10 repetições por tratamento, sendo utilizado o pacote PROC MIXED do Softwear SAS. Os valores médios de peso vivo apresentaram diferença entre as linhagens e interação entre fase e linhagem (P<0,05). Os valores médios das demais variáveis estudadas apresentaram diferença e a interação (P<0,05) entre fase, linhagem e sexo, sendo que de maneira geral as principais diferenças ocorreram a partir da fase de Terminação I, em que as fêmeas das linhagens AgroceresPic e Dalland apresentaram melhores resultados (P<0,05) de RCQ (80,4 e 80,7%, respectivamente) em comparação com os machos (78,8 e 78,7%, respectivamente) e além disso as fêmeas Dalland apresentaram valores superiores (P<0,01) de AOL e ET (45,7cm² e 11,4mm x 38,3cm² e 18,3mm). Conclui-se que as linhagens genéticas avaliadas apresentaram características de carcaça muito interessantes para o mercado atual e que as fêmeas suínas podem ser utilizadas em programas que visem o abate de animais mais pesados.
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Standardized olfactory tests are now available to quantitatively assess disorders of olfaction. A Brazilian-Portuguese version of the University of Pennsylvania Smell Identification Test (UPSIT) is currently being developed specifically for the Brazilian population. The most recent Brazilian-Portuguese version of the UPSIT (UPSIT-Br2) was administered to 88 Brazilian subjects who had no history of neurological or otorhinolaryngological disease. UPSIT-Br2 scores decreased with age, were lower in men than in women, and were lower in subjects with lower income. The degree to which the poorer performance of subjects with lower socio-economic status reflects lack of familiarity with test items is not known. Although this version of the UPSIT provides a sensitive and useful test of smell function for the Brazilian population, a revision of some test items is needed to achieve comparable norms to those found using the North American UPSIT in the United States.
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The enzyme purine nucleoside phosphorylase from Schistosoma mansoni (SmPNP) is an attractive molecular target for the treatment of major parasitic infectious diseases, with special emphasis on its role in the discovery of new drugs against schistosomiasis, a tropical disease that affects millions of people worldwide. In the present work, we have determined the inhibitory potency and developed descriptor- and fragment-based quantitative structure-activity relationships (QSAR) for a series of 9-deazaguanine analogs as inhibitors of SmPNP. Significant statistical parameters (descriptor-based model: r² = 0.79, q² = 0.62, r²pred = 0.52; and fragment-based model: r² = 0.95, q² = 0.81, r²pred = 0.80) were obtained, indicating the potential of the models for untested compounds. The fragment-based model was then used to predict the inhibitory potency of a test set of compounds, and the predicted values are in good agreement with the experimental results
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Thermoanalytical behavior of sodium and potassium salts of pyrrolidinedithiocarbamate (pyr), piperidineditiocarbamate (pip), morpholinedithiocarbamate (mor), hexametileneiminedithiocarbamate (hex), were investigated. In a first step the salts were synthesized and characterized by infrared spectroscopy (FTIR), ¹H and 13C nuclear magnetic resonance (NMR) and elementar analysis. Finally, thermal analytical (TG/DTG and DSC) studies were performed in order to evaluate the thermal stability, as well as the pathways of the thermal decomposition based in the intermediate and final decomposition products.
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Polyrhaphis Audinet-Serville, 1835, gênero de Lamiinae distribuído entre o México e América do Sul (excluindo o Chile e abaixo da latitude 35°S), é revisado. Três espécies novas são descritas: P. baloupae, procedente da Guiana Francesa; P. lanei, proveniente do Brasil (Amazonas e Pará); e P. peruana, do Peru. Duas espécies são sinonimizadas: P. testacea Lane, 1965 (= P. gracilis Bates, 1862) e P. paraensis [= P. papulosa (Olivier, 1795)]. É designado neótipo para P. papulosa. A autoria de P. horrida [= P. spinosa (Drury, 1773)] é discutida. Cerambyx armatus Voet (1778?) é considerado um nome inválido e Lamia armiger Schöenherr, 1817 (= Polyrhaphis armiger) o nome válido dessa espécie. Polyrhaphis spinipennis Laporte, 1840, é excluída da fauna da Colômbia. Novos registros de distribuição: P. argentina Lane, 1978, para o estado de São Paulo (Brasil); P. batesi Hovore & McCarty, 1998, para o Equador; P. belti Hovore & McCarty, 1998 para o Equador e Colômbia; P. gracilis Bates, 1862, para a guiana Francesa; e P. turnbowi Hovore & McCarty, 1998, em dúvida, para o Peru. É apresentada chave para as espécies do gênero.
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study-specific results, their findings should be interpreted with caution
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Aspergillus fumigatus is a common mould whose spores are a component of the normal airborne flora. Immune dysfunction permits developmental growth of inhaled spores in the human lung causing aspergillosis, a significant threat to human health in the form of allergic, and life-threatening invasive infections. The success of A. fumigatus as a pathogen is unique among close phylogenetic relatives and is poorly characterised at the molecular level. Recent genome sequencing of several Aspergillus species provides an exceptional opportunity to analyse fungal virulence attributes within a genomic and evolutionary context. To identify genes preferentially expressed during adaptation to the mammalian host niche, we generated multiple gene expression profiles from minute samplings of A. fumigatus germlings during initiation of murine infection. They reveal a highly co-ordinated A. fumigatus gene expression programme, governing metabolic and physiological adaptation, which allows the organism to prosper within the mammalian niche. As functions of phylogenetic conservation and genetic locus, 28% and 30%, respectively, of the A. fumigatus subtelomeric and lineage-specific gene repertoires are induced relative to laboratory culture, and physically clustered genes including loci directing pseurotin, gliotoxin and siderophore biosyntheses are a prominent feature. Locationally biased A. fumigatus gene expression is not prompted by in vitro iron limitation, acid, alkaline, anaerobic or oxidative stress. However, subtelomeric gene expression is favoured following ex vivo neutrophil exposure and in comparative analyses of richly and poorly nourished laboratory cultured germlings. We found remarkable concordance between the A. fumigatus host-adaptation transcriptome and those resulting from in vitro iron depletion, alkaline shift, nitrogen starvation and loss of the methyltransferase LaeA. This first transcriptional snapshot of a fungal genome during initiation of mammalian infection provides the global perspective required to direct much-needed diagnostic and therapeutic strategies and reveals genome organisation and subtelomeric diversity as potential driving forces in the evolution of pathogenicity in the genus Aspergillus.
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Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p <= 5 x 10(-7)). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1 x 10(-8)) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p = 2 x 10(-8)) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5 x 10(-8); rs1229984-ADH1B, p = 7 x 10(-9); and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility.
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We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the beta Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 +/- 1.0 AU (0.'' 33 +/- 0.'' 01) in 2009 April. Second-epoch observations in 2010 May demonstrate that the companion is physically associated and shows significant orbital motion. Monte Carlo modeling constrains the orbit of PZ Tel B to eccentricities >0.6. The near-IR colors of PZ Tel B indicate a spectral type of M7 +/- 2 and thus this object will be a new benchmark companion for studies of ultracool, low-gravity photospheres. Adopting an age of 12(-4)(+8) Myr for the system, we estimate a mass of 36 +/- 6 M(Jup) based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of the few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 mu m emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion.
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Background: A family of hydrophilic acylated surface (HASP) proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic) and intracellular (amastigote) stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia) have lost HASP genes from their genomes. Methods/Principal Findings: We have used molecular and cellular methods to analyse HASP expression in New World Leishmania mexicana complex species and show that, unlike in L. major, these proteins are expressed predominantly following differentiation into amastigotes within macrophages. Further genome analysis has revealed that the L. (Viannia) species, L. (V.) braziliensis, does express HASP-like proteins of low amino acid similarity but with similar biochemical characteristics, from genes present on a region of chromosome 23 that is syntenic with the HASP/SHERP locus in Old World Leishmania species and the L. (L.) mexicana complex. A related gene is also present in Leptomonas seymouri and this may represent the ancestral copy of these Leishmania-genus specific sequences. The L. braziliensis HASP-like proteins (named the orthologous (o) HASPs) are predominantly expressed on the plasma membrane in amastigotes and are recognised by immune sera taken from 4 out of 6 leishmaniasis patients tested in an endemic region of Brazil. Analysis of the repetitive domains of the oHASPs has shown considerable genetic variation in parasite isolates taken from the same patients, suggesting that antigenic change may play a role in immune recognition of this protein family. Conclusions/Significance: These findings confirm that antigenic hydrophilic acylated proteins are expressed from genes in the same chromosomal region in species across the genus Leishmania. These proteins are surface-exposed on amastigotes (although L. (L.) major parasites also express HASPB on the metacyclic plasma membrane). The central repetitive domains of the HASPs are highly variant in their amino acid sequences, both within and between species, consistent with a role in immune recognition in the host.
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In this paper we use the Hermite-Biehler theorem to establish results on the design of proportional plus integral plus derivative (PID) controllers for a class of time delay systems. Using the property of interlacing at high frequencies of the class of systems considered and linear programming we obtain the set of all stabilizing PID controllers. As far as we know, previous results on the synthesis of PID controllers rely on the solution of transcendental equations. This paper also extends previous results on the synthesis of proportional controllers for a class of delay systems Of retarded type to a larger class of delay systems. (C) 2009 Elsevier Ltd. All rights reserved.