948 resultados para Lenz, Jakob Michael Reinhold, 1751-1792.
Resumo:
In the present study, trail pheromone blends are identified for the first time in termites. In the phylogenetically complex Nasutitermitinae, trail-following pheromones are composed of dodecatrienol and neocembrene, the proportions of which vary according to species, although neocembrene is always more abundant than dodecatrienol (by 25-250-fold). Depending on species, termites were more sensitive to dodecatrienol or to neocembrene but the association of both components always elicited significantly higher trail following, with a clear synergistic effect in most of the studied species. A third component, trinervitatriene, was identified in the sternal gland secretion of several species, but its function remains unknown. The secretion of trail pheromone blends appears to be an important step in the evolution of chemical communication in termites. The pheromone optimizes foraging, and promotes their ecological success. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 20-27.
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Chalcogenolate mediated Michael-aldol cascade reactions consists of a very efficient route to multi-functionalized gamma-hydroxichalcogenides. Although, when selenolates are employed, these gamma-hydroxichalcogenides can be readily converted into the corresponding Morita-Baylis-Hillman adducts by oxidative elimination of the selenium moiety. In this context, herein we present a complete study on the scope and limitations of this reaction. (C) 2012 Elsevier Ltd. All rights reserved.
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Increased uric acid (UA) is strongly linked to cardiovascular disease. However, the independent role of UA is still debated because it is associated with several cardiovascular risk factors including obesity and metabolic syndrome. This study assessed the association of UA with increased high-sensitivity C-reactive protein (hs-CRP), increased ratio of triglyceride to high-density lipoprotein cholesterol (TG/HDL), sonographically detected hepatic steatosis, and their clustering in the presence and absence of obesity and metabolic syndrome. We evaluated 3,518 employed subjects without clinical cardiovascular disease from November 2008 through July 2010. Prevalence of tis-CRP >= 3 mg/L was 19%, that of TG/HDL >= 3 was 44%, and that of hepatic steatosis was 43%. In multivariable logistic regression after adjusting for traditional cardiovascular risk factors and confounders, highest versus lowest UA quartile was associated with hs-CRP >= 3 mg/L (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.01 to 2.28, p = 0.04), TG/HDL >= 3 (OR 3.29, 95% CI 2.36 to 4.60, p <0.001), and hepatic steatosis (OR 3.10, 95% CI 2.22 to 4.32, p <0.001) independently of obesity and metabolic syndrome. Association of UA with hs-CRP >= 3 mg/L became nonsignificant in analyses stratified by obesity. Ascending UA quartiles compared to the lowest UA quartile demonstrated a graded increase in the odds of having 2 or 3 of these risk conditions and a successive decrease in the odds of having none. In conclusion, high UA levels were associated with increased TG/HDL and hepatic steatosis independently of metabolic syndrome and obesity and with increased hs-CRP independently of metabolic syndrome. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;110:1787-1792)
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We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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Objective: Early treatment in sepsis may improve outcome. The aim of this study was to evaluate how the delay in starting resuscitation influences the severity of sepsis and the treatment needed to achieve hemodynamic stability. Design: Prospective, randomized, controlled experimental study. Setting: Experimental laboratory in a university hospital. Subjects: Thirty-two anesthetized and mechanically ventilated pigs. Interventions: Pigs were randomly assigned (n = 8 per group) to a nonseptic control group or one of three groups in which fecal peritonitis (peritoneal instillation of 2 g/kg autologous feces) was induced, and a 48-hr period of protocolized resuscitation started 6 (Delta T-6 hrs), 12 (Delta T-12 hrs), or 24 (Delta T-24 hrs) hrs later. The aim of this study was to evaluate the impact of delays in resuscitation on disease severity, need for resuscitation, and the development of sepsis-associated organ and mitochondrial dysfunction. Measurements and Main Results: Any delay in starting resuscitation was associated with progressive signs of hypovolemia and increased plasma levels of interleukin-6 and tumor necrosis factor-alpha prior to resuscitation. Delaying resuscitation increased cumulative net fluid balances (2.1 +/- 0.5 mL/kg/hr, 2.8 +/- 0.7 mL/kg/hr, and 3.2 +/- 1.5 mL/kg/hr, respectively, for groups.T-6 hrs, Delta T-12 hrs, and.T-24 hrs; p < .01) and norepinephrine requirements during the 48-hr resuscitation protocol (0.02 +/- 0.04 mu g/kg/min, 0.06 +/- 0.09 mu g/kg/min, and 0.13 +/- 0.15 mu g/kg/min; p = .059), decreased maximal brain mitochondrial complex II respiration (p = .048), and tended to increase mortality (p = .08). Muscle tissue adenosine triphosphate decreased in all groups (p < .01), with lowest values at the end in groups Delta T-12 hrs and.T-24 hrs. Conclusions: Increasing the delay between sepsis initiation and resuscitation increases disease severity, need for resuscitation, and sepsis-associated brain mitochondrial dysfunction. Our results support the concept of a critical window of opportunity in sepsis resuscitation. (Crit Care Med 2012; 40:2841-2849)
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The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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Módulo B del Curso La palabra cinematográfica: Didáctica de las relaciones Literatura y Cine, Curso impartido dentro del Programa de Formación y Perfeccionamiento del Profesorado del Colegio oficial de doctores y licenciados en Filosofía y Letras y en Ciencias de Las Palmas (Islas Canarias). Con Convenio de colaboración con la Consejería de Educación, Universidades, Cultura y Deportes (octubre y diciembre de 2004).
Resumo:
Transmissible spongiform encephalopathies (TSEs), or prion diseases, are neurodegenerative disorders that affect humans and mammals. Creutzfeldt-Jakob disease (CJD), the most common TSE in humans, can be sporadic (sCJD), genetic (gCJD), or acquired by infection. All TSEs are characterised by the accumulation of PrPSc, a misfolded form of the cellular protein PrPC. PrPSc is insoluble in detergents, partially resistant to proteolysis and shows a highly enriched β-sheet secondary structure. Six clinico-pathological phenotypes of sCJD have been characterized which correlate at the molecular level with two types (1 or 2) of PrPSc with distinctive physicochemical properties and the genotype at the polymorphic (methionine or valine) codon 129 of the prion protein gene. According to the protein-only hypothesis, which postulates that prions are composed exclusively of PrPSc, the strains of prions that are largely responsible for the wide spectrum of TSE phenotypes are enciphered in PrPSc conformation. In support to this view, studies mainly conducted in experimental scrapie, have shown that several prion strains can be identified based on distinguishing PrPSc biochemical properties. To further contribute to the understanding of the molecular basis of strains and to develop more sensitive strain typing assays in humans we have analyzed PrPSc biochemical properties in two experimental setting. In the first we compared the size of the core after protease digestion and the glycoform pattern of PrPSc before and after transmission of human prions to non human primates or bank voles, whereas in the second we analyzed the conformational stability of PrPSc associated with sCJD, vCJD or fCJD using guanidine hydrochloride (GdnHCl) as denaturant. Combining the results of the two studies, we were able to distinguish five human strains for at least one biochemical property. The present data extend our knowledge about the extent of strain variation and its relationship with PrPSc properties in human TSEs.
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Questo lavoro di tesi è frutto di uno studio sull’addizione viniloga enenantioselettiva di sistemi 3-alchilidenossindolici a nitrotrirene utilizzando un catalizzatore bifunzionale in grado di attivare la posizione gamma del suddetto ossindolo, per mezzo di una reazione acidobase, e di attivare il nitrostirene attraverso interazione via legame a idrogeno. Questo progetto nasce come novità assoluta nel mondo dell’organocatalisi.
Resumo:
L'obiettivo di questa tesi sperimentale è quello di effettuare una reazione di addizione coniugata di Michael di sistemi 1,3-dicarbonilici atroposelettiva su substrati maleimmidici oppurtanamente sostituiti, catalizzata da derivati di alcaloidi naturali della Cinchona. Tale processo risulta importante ed innovativo in quanto si vuole ottenere una reazione di desimmetrizzazione atroposelettiva, contemporaneamente dell'asse prochirale e dei due atomi di carbonio del doppio legame della maleimmide stessa. Partendo dalla reazione di addizione del 2-acetilciclopetanone sulla (N-(2-tert- Butil)fenil)maleimmide, mediante reazioni di screening sono state determinate le condizioni ottimali. Si è poi proceduto a verificare l'estendibilità della reazione verso differenti substrati. Infine si è verificata la stabilità dell'asse di rotazione bloccato neosintetizzato. La sintesi di tali composti è importante per la possibilità di poter successivamente derivatizzare i gruppi sostituenti, in modo da creare building blocks per lo sviluppo di molecole ben più complesse.
Resumo:
The work described in this thesis deals with the development of the asymmetric organocatalytic conjugate addition reaction of 1,3-dicarbonyl compounds to ortho-quinone methides. Due to their instability, these synthetically appealing intermediates have not been fully exploited in catalytic asymmetric settings. In this work, the instability of ortho-quinone methides is overcome by their generation in situ under mild basic conditions, starting from the corresponding sulfonyl derivatives. The bifunctional catalysts used are able to activate both substrates for the reaction, by means of a synergic action of the two catalytic sites, inducing at the same time high enantioselection in the addition step. The reaction leads to the generation of a 2-alkylphenolic framework, featuring a chiral centre at the benzylic position. In particular, the employment of acetylacetone and Meldrum acid as nucleophiles has allowed the obtainment of 4H-chromenes and chroman-2-ones in good yields and generally excellent enantioselectivities. These compounds are synthetic precursors of several natural products, some of which showing interesting biological activity, and of some active pharmaceutical ingredients used in commercial drugs.
Resumo:
Famille de pasteurs, politiciens et entrepreneurs de Zofingue, attestée pour la première fois en 1527, lorsque leur aïeul Jean, tonnelier originaire de Nîmes, obtint la bourgeoisie de Zofingue. Michael (1521-1605), avoyer, l'un de ses cinq fils, est l'ancêtre de la branche des imprimeurs et éditeurs. Après lui, de nombreux R. consolidèrent durablement l'influence de la famille. A partir du XVIIIe s., divers membres firent des carrières politiques, tels Samuel (1706-1786), avoyer, et Rudolf Friedrich (1805-1886), président de la ville. Les R. furent aussi très liés à l'Eglise. Le fils de Michael, Moritz (1557-1615), fut pasteur et doyen à Zofingue. Jusqu'au XIXe s., la famille compta une trentaine d'ecclésiastiques, essentiellement des pasteurs officiant sur le territoire bernois, tels Johann Heinrich ( -> 3) et Michael ( -> 8). Les conseillers Beat (1712-1778) et Niklaus (1734-1766) furent les premiers R. actifs dans la production protoindustrielle de drap. D'autres négociants suivirent jusqu'au milieu du XIXe s. L'architecte Niklaus Emanuel (1744-1815) construisit l'hôtel de ville de Zofingue (1792-1795) de style baroque tardif. Johann Rudolf ( -> 4) se distingua sous la République helvétique (1798-1803). Samuel (1767-1826), conseiller municipal de Zofingue, créa les armoiries du canton d'Argovie en 1803. Les R. s'affirmèrent sur le plan cantonal avec Karl Ludwig ( -> 6), chancelier, et Arnold ( -> 1), conseiller d'Etat et plusieurs fois landamman, et sur le plan fédéral avec Johann Rudolf ( -> 5), conseiller national, et Gottlieb ( -> 2), conseiller aux Etats et chancelier de la Confédération. Johann Rudolf (1803-1874) fonda, en 1833, l'imprimerie Ringier à Zofingue, reprise par son fils Franz Emil (1837-1898). A partir de 1898, Paul August ( -> 9), représentant de la troisième génération d'imprimeurs, agrandit l'entreprise dont il fit la principale imprimerie et maison d'édition de Suisse. Cette expansion se poursuivit après 1960 sous son fils Hans (1906-2003). Avec les fils de celui-ci, Christoph (naissance1941, dans la firme jusqu'en 1991) et Michael (naissance1949), Ringier devint, à partir de 1985, une entreprise multinationale et multimédia. Bibliographie – F. Schoder, Ortsbürger von Zofingen, 1962 – P. Meier, T. Häussler, Zwischen Masse, Markt und Macht, 2009
An examination chair to measure internal rotation of the hip in routine settings: a validation study
Resumo:
OBJECTIVE: To determine the performance of a newly developed examination chair as compared with the clinical standard of assessing internal rotation (IR) of the flexed hip with a goniometer.
METHODS: The examination chair allowed measurement of IR in a sitting position simultaneously in both hips, with hips and knees flexed 90 degrees, lower legs hanging unsupported and a standardized load of 5 kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90 degrees using a goniometer. Within the framework of a population-based inception cohort study, we calculated inter-observer agreement in two samples of 84 and 64 consecutive, unselected young asymptomatic males using intra-class correlation coefficients (ICC) and determined the correlation between IR assessed with examination chair and clinical assessment.
RESULTS: Inter-observer agreement was excellent for the examination chair (ICC right hip, 0.92, 95% confidence interval [CI] 0.89-0.95; ICC left hip, 0.90, 95% CI 0.86-0.94), and considerably higher than that seen with clinical assessment (ICC right hip, 0.65, 95% CI 0.49-0.77; ICC left hip, 0.69, 95% CI 0.54-0.80, P for difference in ICC between examination chair and clinical assessment