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Consistent Picture (consistent + picture)
Selected AbstractsCross-correlated and conventional dipolar carbon-13 relaxation in methylene groups in small, symmetric moleculesCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2007Leila Ghalebani Abstract A theory for dipolar cross-correlated relaxation processes in AMX or AX2 spin system, with special reference to 13C-methylene groups, is reviewed briefly. Simple experiments and protocols for measuring the transfer rates between the carbon-13 Zeeman order and the three-spin order, and for their analogues in the transverse plane, are discussed using a concentrated solution of the disaccharide trehalose as a model system. Experimental data sets consisting of conventional carbon-13 relaxation parameters (T1, T2, and NOE), along with the cross-correlated relaxation rates, are also presented for some small, rigid, polycyclic molecules. These data are interpreted using spectral density functions appropriate to spherical or symmetric tops reorienting according to small-step rotational diffusion model. The analysis results in a consistent picture of the auto- and cross-correlated spin relaxation processes. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 100,115, 2007. [source] Acute toxicity of (chloro-)catechols and (chloro-)catechol-copper combinations in Escherichia coli corresponds to their membrane toxicity in vitroENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2001Nina Schweigert Abstract (Chloro-)catechols are toxic for bacteria and higher organisms, but the mode of action is not yet clearly understood. We have compared the acute toxicity of different chlorinated catechols to Escherichia coli with membrane toxic effects, namely narcosis and uncoupling that we have determined in an in vitro assay. In vitro membrane toxicity was quantified by measuring the accelerated decay of the membrane potential of chromatophores isolated from Rhodobacter sphaeroides. Both acute and membrane toxicity increased with increasing degree of chlorination. Analysis of dose-response curves, pH dependence, and estimated membrane concentrations gave a consistent picture of the mechanisms of membrane toxicity: At pH 7, the higher-chlorinated catechols acted as uncouplers of oxidative and photophosphorylation, and the lower-chlorinated catechols and catechol acted as narcotics. In the case of 3,5-dichlorocatechol and 4-monochlorocatechol at pH 8.8, both mechanisms appeared to contribute to the overall toxicity. Copper exhibited a diverging effect on the toxicity of catechols and of (chloro-)catechols to E. coli. Whereas the presence of copper increased the toxicity of catechol and 4-monochlorocatechol, the toxicity of 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol decreased. Again, the results obtained with in vitro assays agreed with the acute toxicity observed in E. coli: The presence of copper accelerated decay of the membrane potential of catechol and 4-monochlorocatechol; however, the effect was reversed by copper in experiments with 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol. We have proposed a mechanistic model to explain the diverging effects of copper on the uncoupling activities of the different catechols. [source] European phenological response to climate change matches the warming patternGLOBAL CHANGE BIOLOGY, Issue 10 2006ANNETTE MENZEL Abstract Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries (1971,2000). Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade,1 in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species' phenology is responsive to temperature of the preceding months (mean advance of spring/summer by 2.5 days°C,1, delay of leaf colouring and fall by 1.0 day°C,1). The pattern of observed change in spring efficiently matches measured national warming across 19 European countries (correlation coefficient r=,0.69, P<0.001). [source] Theoretical evidence on O,N type smiles rearrangement mechanism: a computational study on the intramolecular cyclization of N -methyl-2-(2-chloropyridin-3-yloxy)-acetamide anionJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 3 2008Hui Sun Abstract Smiles rearrangement (SR) falls under a broad category of organic synthesis for many important compounds. A complete understanding toward SR process appeals to the assistance of theoretical research. Herein, by performing quantum chemistry calculations, we give a theoretical evidence for the mechanism of a representative O,N type SR, the intramolecular cyclization of N -methyl-2-(2-chloropyridin-3-yloxy)acetamide anion. It is found that the SR to the ipso -position involves a two-step mechanism and is energetically more favorable than the direct nucleophilic attack by N atom on the ortho -position. The present result rationalizes well the experimentally observed ipso -SR product and provides a consistent picture of the O,N SR process. Copyright © 2008 John Wiley & Sons, Ltd. [source] Analysis and modeling of organic devicesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2004Y. Roichman Abstract We present self consistent picture of charge injection and transport in low mobility disordered organic based devices. We demonstrate the importance of accounting for charge density effects in both modeling and analysis of devices. We outline a method for the analysis of LEDs and FETs. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A multi-wavelength view of the archetypical CSS radio galaxy 3C303.1: Evidence for shocks and induced star formationASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009C.P. O'Dea Abstract I discuss multi-wavelength data on the archetypal CSS radio galaxy 3C303.1. The radio source is sub-galactic in scale where it can directly affect the ISM of the host galaxy. The emission line kinematics and ionization diagnostics are consistent with energy input from shocks driven by the radio source. The Spitzer IRS spectrum indicates that star formation is occurring in the host galaxy. The HST/ACS/HRC UV image shows UV light which is aligned with the radio source axis. I suggest that the UV light is from young stars which have been triggered by the radio lobes. XMM observations detect the ISM of the host galaxy with a temperature of 0.8 keV plus an additional component whose properties are not well defined. I suggest the second component is a hot shocked gas (T = 45 keV) consistent with a Mach number of 13 for the expanding bow shock. Thus, the multi-wavelength data give a consistent picture in which the radio source drives shocks into the ISM which ionize dense clouds, trigger star formation, and shock heat the hot component of the ISM to very high temperature. These observations demonstrate that radio sources can provide significant feedback to their host galaxy (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Review and meta-analysis of the phenomenology and clinical characteristics of mania in children and adolescentsBIPOLAR DISORDERS, Issue 6 2005Robert A Kowatch Objective:, Using predetermined criteria for study quality and methods, a literature review and meta-analysis of seven reports about pediatric bipolar disorder (BPD) was conducted to determine if there is a consistent picture of the phenomenology and clinical characteristics of BPD in children and adolescents. Methods:, Searches were conducted in MedLine and PsycINFO using the terms mania, BPD, children and adolescents, and was limited to published articles in peer-reviewed journals. Seven reports were selected that met the following criteria: a systematic method for the elicitation and reporting of symptoms and clinical characteristics of subjects; subjects were interviewed by a trained researcher or clinician; ages 5,18 years; use of a diagnostic system, either DSM or RDC for categorization; a consensus method for the establishment of the diagnosis of BPD. Results:, Most DSM-IV symptoms of mania were common in the children and adolescents with BPD with the most common symptoms being increased energy, distractibility, and pressured speech. On average, four of five bipolar cases also showed threshold levels of irritable mood and grandiosity, and more than 70% of all cases showed elated/euphoric mood, decreased need for sleep, or racing thoughts. Roughly 69% of cases also showed poor judgment, whereas only half of bipolar cases demonstrated flight of ideas, and slightly more than one-third showed hypersexuality or psychotic features. Conclusions:, The clinical picture that emerges is that of children or adolescents with periods of increased energy (mania or hypomania), accompanied by distractibility, pressured speech, irritability, grandiosity, racing thoughts, decreased need for sleep and euphoria/elation. [source] Chemoenzymatic synthesis and properties of Schiff bases containing (R)-1-(9-anthryl)ethylamineCHIRALITY, Issue 8 2002Marin Roje Abstract Racemic 1-(9-anthryl)ethylamine (10), obtained in 70% overall yield from commercial 9-cyanoanthracene, was kinetically resolved by the Candida antarctica A lipase-catalyzed acetylation with isopropyl acetate as acyl donor, affording (R)-(+)- 10 with 95.8% enantiomeric excess (e.e.) (E- value 43.5), which afforded Schiff bases (R)- 4 and(R)- 8.1H-NMR, CD, and MM2 calculations offer a consistent picture of the conformational properties of these potential ligands and an explanation for the limited enhancement of enantioselectivity in cyclopropanation of styrene by their Cu(I) complexes, as compared with previously studied ligands in this series. Chirality 14:625,631, 2002. © 2002 Wiley-Liss, Inc. [source] | |||||||||||||||||||