Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Relevant

  • compound relevant
  • condition relevant
  • consideration relevant
  • data relevant
  • evidence relevant
  • factor relevant
  • finding relevant
  • gene relevant
  • information relevant
  • intervention relevant
  • issues relevant
  • knowledge relevant
  • literature relevant
  • models relevant
  • only relevant
  • parameter relevant
  • policy relevant
  • property relevant
  • question relevant
  • research relevant
  • scale relevant
  • studies relevant
  • value relevant
  • variable relevant
  • very relevant

  • Terms modified by Relevant

  • relevant activity
  • relevant actor
  • relevant allergen
  • relevant alternative
  • relevant amount
  • relevant antigen
  • relevant application
  • relevant approach
  • relevant area
  • relevant article
  • relevant aspect
  • relevant attribute
  • relevant biomarker
  • relevant change
  • relevant character
  • relevant characteristic
  • relevant citation
  • relevant clinical
  • relevant clinical trials
  • relevant component
  • relevant concentration
  • relevant concept
  • relevant conclusion
  • relevant condition
  • relevant confounder
  • relevant consideration
  • relevant content
  • relevant context
  • relevant contribution
  • relevant covariate
  • relevant cue
  • relevant data
  • relevant databases
  • relevant determinant
  • relevant development
  • relevant difference
  • relevant disease
  • relevant document
  • relevant dose
  • relevant drug interaction
  • relevant effect
  • relevant effects
  • relevant electronic databases
  • relevant endpoint
  • relevant evidence
  • relevant example
  • relevant experience
  • relevant experiment
  • relevant factor
  • relevant feature
  • relevant finding
  • relevant form
  • relevant function
  • relevant gene
  • relevant history
  • relevant impact
  • relevant increase
  • relevant indicator
  • relevant information
  • relevant interaction
  • relevant investigation
  • relevant issues
  • relevant item
  • relevant journal
  • relevant knowledge
  • relevant level
  • relevant literature
  • relevant marker
  • relevant material
  • relevant measure
  • relevant mechanism
  • relevant methods
  • relevant model
  • relevant models
  • relevant molecule
  • relevant mutation
  • relevant number
  • relevant outcome
  • relevant paper
  • relevant parameter
  • relevant part
  • relevant phenomenoN
  • relevant polymorphism
  • relevant problem
  • relevant process
  • relevant property
  • relevant proportion
  • relevant protein
  • relevant publication
  • relevant question
  • relevant reference
  • relevant report
  • relevant research
  • relevant result
  • relevant review
  • relevant risk
  • relevant risk factor
  • relevant role
  • relevant scale
  • relevant section
  • relevant situation
  • relevant source
  • relevant species
  • relevant stakeholder
  • relevant stimulus
  • relevant structure
  • relevant studies
  • relevant symptom
  • relevant target
  • relevant techniques
  • relevant theory
  • relevant today
  • relevant tool
  • relevant trait
  • relevant trials
  • relevant variable
  • relevant way
  • relevant website
  • relevant work

  • Selected Abstracts


    ADDICTION, Issue 10 2009
    No abstract is available for this article. [source]


    ADDICTION, Issue 10 2009
    No abstract is available for this article. [source]


    EVOLUTION, Issue 6 2007
    David M. Hillis
    First page of article [source]

    Impact of the international program for quality assessment and standardization for immunological measures relevant to HIV/AIDS: QASI

    CYTOMETRY, Issue 2 2002
    Francis Mandy
    Abstract Measurements of CD4 T-cell levels are essential for the assessment of human immunodeficiency virus (HIV) disease course, clinical staging, epidemiological studies, and decisions regarding prophylactic therapies against opportunistic infection. Until now, only in the industrialized countries was T-cell subset monitoring considered a practical option to assess disease progression. The Quality Assessment and Standardization for Immunological Measures Relevant to HIV/AIDS (QASI) program was established in 1997 to meet performance assessment for immunophenotyping laboratories in countries where such service is not available. The QASI program is provided at no cost to any laboratory in a resource-poor setting that wishes to participate. This report describes the beneficial impact of participation in the QASI program. Carefully selected commercial stabilized whole blood preparations were sent regularly to participating laboratories. Participants reported the T-cell subset values they obtained by flow cytometry. Once the aggregate mean values for the T-cell subsets were established for the shipment, a comprehensive and confidential report was sent to each laboratory. The results from five consecutive shipments were analyzed. The coefficient of variation decreased from 7.2% to 4.7% and from 14.2% to 8.8% for percent and absolute CD4 T-cell counts, respectively. With the implementation of the QASI program using commercial stabilized whole blood specimens, it is possible to reduce interlaboratory error. This study illustrates that a quality assessment program can improve the overall performance of laboratories. Reducing interlaboratory variation can enhance significantly the effectiveness of multicenter HIV vaccine or drug trial evaluation. Cytometry (Clin. Cytometry) 50:111,116, 2002. © 2002 Wiley-Liss, Inc. [source]

    Is Tolerance to Antiepileptic Drugs Clinically Relevant?

    EPILEPSIA, Issue 8 2006
    Giuliano Avanzini
    No abstract is available for this article. [source]

    GABAergic projections from the hippocampus to the retrosplenial cortex in the rat

    Toshio Miyashita
    Abstract The retrosplenial cortex (RS) in rats has been implicated in a wide range of behaviors, including spatial navigation and memory. Relevant to this, the RS is closely interconnected with the hippocampus by multiple direct and indirect routes. Here, by injecting the retrograde tracer cholera toxin subunit B conjugated with Alexa488 (CTB-Alexa488) in the granular retrosplenial cortex (GRS), we demonstrate a moderately dense non-pyramidal projection from CA1. Neurons are in several layers, but mainly (about 65%) at the border of the stratum radiatum (SR) and stratum lacunosum moleculare (SLM). In particular, by double-labeling with GAD67 or ,-aminobutyric acid (GABA), we establish that these neurons are GABAergic. Further immunocytochemical screening for calcium-binding proteins, somatostatin (SS) or cholecystokinin (CCK) failed to identify additional neurochemical subgroups; but a small subset (about 14%) is positive for the m2 muscarinic acetylcholine receptor (M2R). Terminations target layer 1 of the GRS, as shown by biotinylated dextran amine (BDA) injections into CA1 and confirmed by a very superficial injection of CTB-Alexa488 in GRS. The superficial injection shows that there is a sparse GABAergic projection from the subiculum to layer 1 of the GRS, in addition to the dense excitatory connections to layer 3. The role of these dual inhibitory,excitatory pathways , within the subiculum, and in parallel from CA1 and the subiculum , remains to be determined, but may be related to synchronized oscillatory activity in the hippocampal complex and GRS, or to the generation of rhythmic activity within the GRS. [source]

    Currents: Articles in Brief

    Rachael Green
    Seven Strategies for Retaining Top Talent Five Ways to Re-recruit Your Employees Building an Effective Global Business Team Lead for Loyalty Do the Right Thing Making Performance Management Relevant Can Pay for Performance Really Work? [source]

    Using current consumer issues to involve students in research

    Elizabeth B. Carroll
    Abstract The value of involving students in research has been well documented. By including students in research, active and independent learning opportunities are provided, the importance of inquiry and investigation is emphasized, and connections between course material and the discipline become evident. Relevant opportunities for involving students in research projects can sometimes be elusive. Faculty time constraints limit the number of projects that can be undertaken and the number of students involved. Furthermore, many students become intimidated when told that they are required to carry out a research project. The purpose of this study was to use current consumer issues to involve undergraduate students in a relevant research project. The research project was implemented in class settings with teams of students. Faculty selected contemporary consumer issues based upon perceived student interest and experiences as consumers. By using issues of high relevance and familiarity to students and using the team approach within a course that faculty members were already assigned to teach, the issues of time constraint for the faculty members and increased levels of comfort for students were addressed. Prior to undertaking the project, students were instructed in appropriate research methods. Research methods utilized included student development of survey instruments, collection and recording of data, interpretation of data and presentation of results. Students became familiar with various research practices. By working as team members, the students' comfort level for being involved in research increased; however, other common group challenges arose. Relevant, contemporary consumer issues carry high relevance and interest for student groups, helping generate enthusiasm for the research process. The focus on involving students in research continues to be emphasized. By using research topics related to student's experiences as consumers, students are more readily engaged in undertaking research projects. Through these relevant research projects, students' consumer decision making is positively impacted. [source]

    Biological Indicator Systems in Floodplains , a Review

    Frank Dziock
    Abstract Based on a literature review, the different approaches to biological indicator systems in floodplains are summarised. Four general categories of bioindication are defined and proposed here: 1. Classification indicators, 2.1 Environmental indicators, 2.2 Biodiversity indicators, 3. Valuation indicators. Furthermore, existing approaches in floodplains are classified according to the four categories. Relevant and widely used approaches in floodplains are explained in more detail. The results of the RIVA project are put into the context of these indication approaches. It is concluded that especially functional assessment approaches using biological traits of the species can be seen as very promising and deserve more attention by conservation biologists and floodplain ecologists. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    An Internalist View on the Value of Life and Some Tricky Cases Relevant to it

    Theo van Willigenburg
    If we understand death as the irreversible loss of the good of life, we can give meaning to the idea that for suffering patients in the end stage of their illness, life may become an evil and death no longer a threat. Life may lose its good already in the living person. But what does the good of life consist in, then? I defend an internalist view according to which the goodness of life is intrinsically related to the attitudes, concerns, interests and experiences of the person who is leading the life. This results in the contention that the core of what we understand as the value of a person's life is to be identified with what makes life go well for the person living the particular life. This internalist view does not presuppose (or imply) hedonism or mentalism, nor does it pose an experience requirement. Something may be good for you, because it is valuable as seen from your authentic viewpoint, even if you do not actually experience this goodness, or think otherwise because you are mistaken about your own well-being. To test this position, and the authenticity-requirement it includes, I discuss three cases of patients who are persistent in denying that in their life any value is left and who contend that death is no worse than further living. Internalism acknowledges that in the life of these patients there may be 'functionings' and 'beings' that are worthwhile, where the test of value is at least partially independent of subjective assessment. Still, internalism claims that something truly valuable can only contribute to the good of one's life of it has positive meaning as seen from the attitudinal viewpoint that identifies oneself. [source]

    Individual Differences in Attitudes Relevant to Juror Decision Making: Development and Validation of the Pretrial Juror Attitude Questionnaire (PJAQ),

    Len Lecci
    This study involves scale development using theoretically derived items from previous measures and a lay consensual approach for generating new items. Confirmatory factor analysis was used to validate the emergent constructs assessing individual differences in attitudes of prospective jurors. Using case summaries, the Pretrial Juror Attitude Questionnaire (PJAQ) demonstrates superior predictive validity over commonly employed measures of pretrial bias. The PJAQ confirms the importance of theoretically derived constructs assessed by other scales and introduces new constructs to the jury decision-making literature. The attitudes assessed by the PJAQ are conviction proneness, system confidence, cynicism toward the defense, racial bias, social justice, and innate criminality. Implications for assessing such attitudes and for better understanding the decision-making process of jurors are discussed. [source]

    WHO Atlas on Global Resources for Persons with Intellectual Disabilities 2007: Key Findings Relevant for Low- and Middle-Income Countries

    Céline Mercier
    Abstract, The World Health Organization (WHO) Atlas-ID project was designed to collect, compile, and disseminate information on intellectual disabilities (ID) services and resources from across the world. This paper aims at selecting findings in the Atlas-ID that can be used as a tool for advocacy, human rights awareness, development planning, and monitoring changes regarding resources for persons with intellectual disabilities and their families in countries with the lowest levels of income in the world. After consultation with experts in the field of ID, a questionnaire and its accompanying glossary were developed. This questionnaire was completed by national respondents from 147 countries, areas, and territories that are WHO members (response rate of 74.6% corresponding to 94.6% of the world population). Cross-tabulations were calculated according to WHO region that the countries belong to as well as their levels of income. The data from the Atlas-ID allowed for documenting similarities and differences among the poorest and the richest countries of the world in relation to ID. The most striking differences pertain to the areas of information, judicial protection, government benefits, financing, availability, and access to services. The Atlas-ID allowed the identification of similarities and differences in resources and services between the four World Bank categories of countries income, and it demonstrated the extent of unmet needs in low-income and low-middle-income countries, as well as some critical gaps between these countries and the high-level income countries. [source]

    Relevance: A review of the literature and a framework for thinking on the notion in information science.

    Part II: nature, manifestations of relevance
    Relevant: Having significant and demonstrable bearing on the matter at hand., Relevance: The ability as of an information retrieval system to retrieve material that satisfies the needs of the user. ,Merriam-Webster Dictionary 2005 Relevance is a, if not even the, key notion in information science in general and information retrieval in particular. This two-part critical review traces and synthesizes the scholarship on relevance over the past 30 years and provides an updated framework within which the still widely dissonant ideas and works about relevance might be interpreted and related. It is a continuation and update of a similar review that appeared in 1975 under the same title, considered here as being Part I. The present review is organized into two parts: Part II addresses the questions related to nature and manifestations of relevance, and Part III addresses questions related to relevance behavior and effects. In Part II, the nature of relevance is discussed in terms of meaning ascribed to relevance, theories used or proposed, and models that have been developed. The manifestations of relevance are classified as to several kinds of relevance that form an interdependent system of relevances. In Part III, relevance behavior and effects are synthesized using experimental and observational works that incorporate data. In both parts, each section concludes with a summary that in effect provides an interpretation and synthesis of contemporary thinking on the topic treated or suggests hypotheses for future research. Analyses of some of the major trends that shape relevance work are offered in conclusions. [source]

    Meta-analysis: longitudinal studies of serum vitamin D and colorectal cancer risk

    L. YIN
    Summary Background, In 1980, Garland hypothesized that lower levels of vitamin D resulting from much weaker UV-B radiation at higher latitudes may account for the striking geographical pattern of cancer mortality. Further research has been conducted over the past 20 years. Aim, To perform a systematic review and meta-analysis of longitudinal studies on the association between serum 25 hydroxyvitamin D (25(OH)D) and the risk of colorectal cancer (CRC). Methods, Relevant studies published until September 2008 were identified by systematically searching Ovid Medline, EMBASE, and ISI Web of Knowledge databases and by cross-referencing. Due to the heterogeneity of studies in categorizing serum vitamin D levels, all results were recalculated for an increase of serum 25(OH)D by 20 ng/mL. Summary odds ratios (ORs) were calculated using meta-analysis methods. Results, Overall, eight original articles reporting on the association between serum 25(OH) D and CRC risk were included. In meta-analyses, summary ORs (95% confidence intervals) for the incidence of CRC, colon cancer and rectal cancer associated with an increase of 25(OH)D by 20 ng/mL were 0.57 (0.43,0.76), 0.78 (0.54,1.13) and 0.41 (0.11,1.49). No indication for publication bias was found. Conclusions, Our results support suggestions that serum 25(OH)D is inversely related to CRC risk. [source]

    Review article: bacterial translocation in the critically ill , evidence and methods of prevention

    M. GATT
    Summary Background Delayed sepsis, systemic inflammatory response syndrome (SIRS) and multiorgan failure remain major causes of morbidity and mortality on intensive care units. One factor thought to be important in the aetiology of SIRS is failure of the intestinal barrier resulting in bacterial translocation and subsequent sepsis. Aim This review summarizes the current knowledge about bacterial translocation and methods to prevent it. Methods Relevant studies during 1966,2006 were identified from a literature search. Factors, which detrimentally affect intestinal barrier function, are discussed, as are methods that may attenuate bacterial translocation in the critically ill patient. Results Methodological problems in confirming bacterial translocation have restricted investigations to patients undergoing laparotomy. There are only limited data available relating to specific interventions that might preserve intestinal barrier function or limit bacterial translocation in the intensive care setting. These can be categorized broadly into pre-epithelial, epithelial and post-epithelial interventions. Conclusions A better understanding of factors that influence translocation could result in the implementation of interventions which contribute to improved patient outcomes. Glutamine supplementation, targeted nutritional intervention, maintaining splanchnic flow, the judicious use of antibiotics and directed selective gut decontamination regimens hold some promise of limiting bacterial translocation. Further research is required. [source]

    Is Kaldor's Theory of Money Supply Endogeneity Still Relevant?

    METROECONOMICA, Issue 1 2001
    Giancarlo Bertocco
    Contemporary monetary theory is characterized by the predominance of the monetarist thesis. Paradoxically, the widespread acceptance of the monetarists' conclusions has coincided with the disappearance of the stable relation between money stock and nominal income from the 1980s onwards. These results did not call the monetarist theory into question, but instead stimulated the elaboration of various proposals for the modification of the monetary authorities' operative schemes. Each of these proposals gives rise to some perplexity. These anomalies provide the justification for this paper, which sets out to analyse the characteristics of the money supply endogeneity theory, a theoretical approach initiated in the 1970s thanks to Kaldor's seminal contribution, with the objective of demonstrating the inconsistencies in the monetarists' conclusions. It is intended to show that the debate on the endogeneity theory developed by the post-Keynesians has overlooked an essential aspect of Kaldor's theory, the examination of which permits: (a) the elaboration of an important criticism of monetarism; and (b) the development of a theory of credit and of financial intermediaries that highlights elements of Keynes's theory that have been neglected by the traditional interpretation. [source]

    Legal Issues Relevant to Non-heart beating Organ Donation

    Catherine Plowright
    No abstract is available for this article. [source]

    Databases for outcomes research: what has 10 years of experience taught us?

    Lynn Bosco MD
    Abstract This paper describes how the mission of the Agency for Healthcare Research and Quality (AHRQ) is being executed through the many programs that it has developed and implemented. The Evidence-based Practice Center program was developed to provide systematic reviews on common and expensive conditions and health technologies and to ensure that this information is used to improve health care outcomes and costs. The National Guidelines Clearinghouse provides an internet-based source of clinical practice guidelines that are produced by clinical specialty organizations for the primary purpose of improving health care delivery and outcomes. Relevant to this symposium on databases, AHRQ has supported the development of databases to track hospital utilization on a state-by-state basis. The Healthcare Cost and Utilization Project (HCUP) allows comparisons between states and within regions of individual states. New initiatives have been launched to evaluate interventions across systems rather than focusing on the individual patient (Translating Research into Practice,TRIP). The Centers for Education and Research on Therapeutics (CERTs) program was developed to conduct real world evaluations to better understand the benefits and risks of single and combined therapy. Both programs further the mission of the AHRQ to improve the outcomes and quality of health care, with additional focus on the cost-effectiveness, patient safety, and increasing access to care for all. Information on programs developed by the AHRQ is available in more detail at the Agency Web site Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Molecular Fluorescence Excitation,Emission Matrices Relevant to Tissue Spectroscopy,

    Ralph S. DaCosta
    ABSTRACT In vivo and ex vivo studies of fluorescence from endogenous and exogenous molecules in tissues and cells are common for applications such as detection or characterization of early disease. A systematic determination of the excitation,emission matrices (EEM) of known and putative endogenous fluorophores and a number of exogenous fluorescent photodynamic therapy drugs has been performed in solution. The excitation wavelength range was 250,520 nm, with fluorescence emission spectra collected in the range 260,750 nm. In addition, EEM of intact normal and adenomatous human colon tissues are presented as an example of the relationship to the EEM of constituent fluorophores and illustrating the effects of tissue chromophore absorption. As a means to make this large quantity of spectral data generally available, an interactive database has been developed. This currently includes EEM and also absorption spectra of 35 different endogenous and exogenous fluorophores and chromophores and six photosensitizing agents. It is intended to maintain and extend this database in the public domain, accessible through the Photochemistry and Photobiology website ( [source]

    Mechanistic Studies of Catechol Generation from Secondary Quinone Amines Relevant to Indole Formation and Tyrosinase Activation

    Edward J. Land
    The biological significance of the spontaneous cyclization and redox reactions of ortho -quinone amines is that these appear to be the mechanism of formation of the indolic components of melanin and are also involved in the autoactivation of tyrosinase. We have previously shown that activation of tyrosinase is prevented by the formation of a cyclic betaine from a tertiary amine analogue. Evidence is presented to show that cyclization of ortho -quinones by Michael addition also occurs in the oxidation of secondary catecholamines. Three varieties of cyclic product have been detected and their formation is influenced by the nature of the N -substituent. Five-membered betaine rings form directly and, although six- and seven-membered rings also form, a transient spiro isomer of the ortho -quinone was in some cases detected as an intermediate. The heterocyclic products formed as betaines undergo redox exchange with residual quinone to form the corresponding aminochromes. We have established the kinetic constants of these reactions, either directly by pulse radiolysis measurements or by inference using a computer model of the reaction pathway to fit the observed data. To investigate the potential biological applications of this chemistry the system was also examined by tyrosinase-catalysed oxidation of the catecholamine substrates in which there is re-oxidation of the catechol formed by the redox exchange reaction and enables measurement of oxygen utilization stoichiometry. We show that the redox exchange reaction is unaffected by side-chain modification whereas cyclization is dependent on both electronic and steric factors. In the light of these studies we conclude that the failure of tertiary amine-derived betaines to undergo redox exchange, and thus block in vitro activation of tyrosinase, is due to the absence of a second exchangeable proton. [source]

    What Small Spatial Scales Are Relevant as Electoral Contexts for Individual Voters?

    The Importance of the Household on Turnout at the 2001 General Election
    For many years, scholars of voting behavior have been thwarted in their attempts to identify micro spatial variations in turnout by data limitations. This has meant that most analyses have been ecological, which has implications for valid inference. Here, for the first time, a hierarchical approach is used to show the relative importance of several micro spatial scales, including the household, on voter participation. The findings highlight the importance of the household context. While those who live together often turn out together, the relative level of clustering within households as opposed to between geographical areas is found to be more important for two-person households compared to other households. Even after taking account of whether individuals are likely to self-select others from similar social backgrounds or with similar political attitudes, there is strong evidence of large and significant household effects on voter participation. [source]

    Innentitelbild: Neptunium Diverges Sharply from Uranium and Plutonium in Crystalline Borate Matrixes: Insights into the Complex Behavior of the Early Actinides Relevant to Nuclear Waste Storage (Angew. Chem.

    ANGEWANDTE CHEMIE, Issue 7 2010
    Eine große Sammlung von kristallinen Uran-, Neptunium- und Plutoniumboraten wurde synthetisiert, um zu untersuchen, wie sich das chemische Verhalten dieser benachbarten Elemente unterscheiden könnte. In der Zuschrift auf S.,1285,ff. berichten T.,E. Albrecht-Schmitt et,al. über das höchst ungewöhnliche Verhalten von Neptunium, das mehrere schichtförmige Neptunylborate mit nanoskaligen Strukturen bildet, die Np in den Oxidationsstufen +IV, +V und +VI enthalten. Die Eigenschaften dieser Verbindungen stehen im scharfen Gegensatz zu denen der Uran- und Plutoniumspezies, die lediglich UVI oder PuVI aufweisen. [source]

    Neptunium Diverges Sharply from Uranium and Plutonium in Crystalline Borate Matrixes: Insights into the Complex Behavior of the Early Actinides Relevant to Nuclear Waste Storage,

    ANGEWANDTE CHEMIE, Issue 7 2010
    Shuao Wang
    Anders als die anderen: Neptuniumborate unterscheiden sich von Uran- und Plutoniumboraten: Sie liegen als gemischtvalente Verbindungen mit jeweils dreierlei Koordinationsumgebungen und Oxidationstufen vor (siehe Bild; Polyeder: NpIV hellblau, NpV dunkelblau, NpVI grün, B gelb; Kugeln: O rot, K oder Ba blau). [source]

    Management of patients with refractory migraine and PFO: Is MIST I Relevant?

    Jonathan Tobis MD
    Abstract The results of the randomized clinical trial entitled: Migraine Intervention with Starflex Technology (MIST), produced surprising and disappointing results on the effect of PFO closure to decrease migraine headaches. There have been allegations of misrepresentation of the effectiveness of this device. These issues have significant implications in how randomized clinical trials are performed that will impact current and future planned trials of PFO closure to treat migraine headaches. © 2008 Wiley-Liss, Inc. [source]

    ChemInform Abstract: Neptunium Diverges Sharply from Uranium and Plutonium in Crystalline Borate Matrixes: Insights into the Complex Behavior of the Early Actinides Relevant to Nuclear Waste Storage.

    CHEMINFORM, Issue 16 2010
    Shuao Wang
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Studies of Palladium-Catalyzed Coupling Reactions for Preparation of Hindered 3-Arylpyrroles Relevant to (-)-Rhazinilam and Its Analogues.

    CHEMINFORM, Issue 26 2002
    Leon Ghosez
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    Theoretical Exploration of the Oxidative Properties of a [(trenMe1)CuO2]+ Adduct Relevant to Copper Monooxygenase Enzymes: Insights into Competitive Dehydrogenation versus Hydroxylation Reaction Pathways

    Aurélien de, Lande Dr.
    Abstract Singlet and triplet H-transfer reaction paths from CH and NH bonds were examined by means of DFT and spin-flip TD-DFT computations on the [(trenMe1)CuO2]+ adduct. The singlet energy surfaces allow its evolution towards H2O2 and an imine species. Whereas NH cleavage appears to be a radical process, CH rupture results in a carbocation intermediate stabilized by an adjacent N atom and an electrostatic interaction with the [CuIOOH] metal core. Upon injection of an additional electron, the latter species straightforwardly forms a hydroxylated product. Based on these computational results, a new mechanistic description of the reactivity of copper monooxygenases is proposed. [source]

    Dithiolate-Bridged Fe-Ni-Fe Trinuclear Complexes Consisting of Fe(CO)3,n(CN)n (n=0, 1) Components Relevant to the Active Site of [NiFe] Hydrogenase

    Satyanarayan Pal Dr.
    Abstract Step-by-step: A trinuclear Fe-Ni-Fe complex 1 was synthesized from the reaction of [Fe(CO)4I2] with Li2[Ni(norbornane- exo -2,3-dithiolate)2]. The CO ligands in 1 were transformed into CN, upon treatment with ,N(SiMe3)2, and the monocyanide complex 3 and the dicyanide complex 4 were obtained. Complexes 3 and 4 were found to react with protonic acids, whereas 1 is robust. A dithiolate-bridged Fe-Ni-Fe trinuclear carbonyl complex [(CO)3Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (1, ndt=norbornane- exo -2,3-dithiolate) has been synthesized from the reaction of [Fe(CO)4I2] and Li2[Ni(ndt)2]. This reaction was found to occur with concomitant formation of a tetranuclear cluster [Ni3(,-ndt)4FeI] (2). Treatment of 1 with Na[N(SiMe3)2] transforms some of the CO ligands into CN,, and the monocyanide complex (PPh4)[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (3) and the dicyanide complex (PPh4)2[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)2(CN)] (4) were isolated. X-ray structural analyses of the trinuclear complexes revealed a Fe-Ni-Fe array in which the metal centers are connected by the ndt sulfur bridges and direct FeNi bonds. Hydrogen bonding between the CN ligand in 3 and cocrystallized ethanol was found in the solid-state structure. The monocyanide complex 3 and dicyanide complex 4 reacted with acids such as HOTf or HCl generating insoluble materials, whereas complex 1 did not react. [source]

    Abductive Diagnosis Using Time-Objects: Criteria for the Evaluation of Solutions

    Elpida T. Keravnou
    Diagnostic problem solving aims to account for, or explain, a malfunction of a system (human or other). Any plausible potential diagnostic solution must satisfy some minimum criteria relevant to the application. Often there will be several plausible solutions, and further criteria will be required to select the "best" explanation. Expert diagnosticians may employ different, complex criteria at different stages of their reasoning. These criteria may be combinations of some more primitive criteria, which therefore should be represented separately and explicitly to permit their flexible and transparent combined usage. In diagnostic reasoning there is a tight coupling between the formation of potential solutions and their evaluation. This is the essence of abductive reasoning. This article presents an abductive framework for diagnostic problem solving. Time-objects, an association of a property and an existence, are used as the representation formalism and a number of primitive, general evaluation criteria into which time has been integrated are defined. Each criterion provides an intuitive yardstick for evaluating the space of potential solutions. The criteria can be combined as appropriate for particular applications to define plausible and best explanations. The central principle is that when time is diagnostically significant, it should be modeled explicitly to enable a more accurate formulation and evaluation of diagnostic solutions. The integration of time and primitive evaluation criteria is illustrated through the Skeletal Dysplasias Diagnostician (SDD) system, a diagnostic expert system for a real-life medical domain. SDD's notions of plausible and best explanation are reviewed so as to show the difficulties in formalizing such notions. Although we illustrate our work by medical problems, it has been motivated by consideration of problems in a number of other domains (fermentation monitoring, air and ground traffic control, power distribution) and is intended to be of wide applicability. [source]

    A measure for mesh compression of time-variant geometry

    Prasun Mathur
    Abstract We present a novel measure for compression of time-variant geometry. Compression of time-variant geometry has become increasingly relevant as transmission of high quality geometry streams is severely limited by network bandwidth. Some work has been done on such compression schemes, but none of them give a measure for prioritizing the loss of information from the geometry stream while doing a lossy compression. In this paper we introduce a cost function which assigns a cost to the removal of particular geometric primitives during compression, based upon their importance in preserving the complete animation. We demonstrate that the use of this measure visibly enhances the performance of existing compression schemes. Copyright © 2004 John Wiley & Sons, Ltd. [source]