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Specific Features (specific + feature)
Selected AbstractsResearching Small Firms and Entrepreneurship in the U.K.: Developments and DistinctivenessENTREPRENEURSHIP THEORY AND PRACTICE, Issue 2 2008Robert A. Blackburn This article charts the development of research on small firms and entrepreneurship in the U.K. over the last 30 years or so and identifies distinctive characteristics of the current orientation of the research field. The paper analyses the rapid increase in the number of researchers contributing to the field over the period, together with its growing legitimacy and institutionalization. One of the key underlying themes is the rich diversity of approaches, reflecting the origins and development path, with clusters of researchers ranging from those with normative objectives to those who view the phenomenon as an object of study. Specific features of the U.K. research field identified include its policy orientation; a rich empirical tradition, with methodological diversity; an emphasis on small firms, and entrepreneurship as a subject for study, rather than an object for promotion; aspects of the boundaries and language of small business and entrepreneurship research; and pre-paradigmatic and middle range theory development i.e., somewhere between grand theory and empirical findings. [source] Verallgemeinerungsfähige Merkmale und Besonderheiten des SprühkompaktierensMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 1 2003K. Bauckhage Sprayforming; Modelling Microstructure; Geometry Abstract Dadurch, daß beim Sprühkompaktieren die schnelle Erstarrung und Abkühlung des Materials das Ausmaß von Entmischungen eindämmen, können Makroseigerungen unterbunden und Anreicherungen an den Korngrenzen deutlich verringert werden. Ferner wird das Risiko der Lunker- und Warmrißbildung durch den Impuls des Massetransportes während des Kompaktiervorganges stark reduziert. Dies bedeutet, daß solche Materialien, die bspw. beim Gießen zu starker Seigerung neigen und besonders anfällig für die Lunkerbildung und/oder Warmrißbildung sind sowie bei Umformverfahren zur Zeilenbildung von Carbiden, Nitriden oder Sulfiden neigen, mit Hilfe des Sprühkompaktierens im Freiformverfahren mit großen Abmaßen chemisch homogen und fehlerfrei herstellbar werden. Ein besonderes Merkmal sprühkompaktierter Deposits ist ihr feines Gefüge und ihre vergleichsweise hohe Duktilität. Die Besonderheiten des neuartigen Urformverfahrens werden anhand von Beispielen erläutert. Characteristic Features and Specific Qualifications of the Sprayforming Process to be Generalized The solidification and cooling process of spray formed materials predominates the extent of any segregation and separation process, which is conducive to avoid macro-segregation and to diminish concentration of alloying components at the grain boundaries. The risk of coarse porosity or of hot cracking is reduced significantly by the momentum of the mass flow during spray deposition. This means that those materials which e.g. during the casting process tend to establish strong segregation effects and cavities and/or hot cracks as well as those which tend to create filaments of carbides, nitrides or sulphides during rolling can be generated by the spray forming process in large dimensions with chemical homogeneity and without any of those defects. A characteristic feature of spray formed materials is the fine equiaxed grain structure and the high ductility. Specific features of this new free forming process will be discussed. [source] Specific features of 3.8-eV emission in TL spectra of oxygen-deficient corundumPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2005I. A. Weinstein Abstract The behavior of the 3.8-eV band in the thermoluminescence spectrum of anion-deficient single crystals of ,-Al2O3 has been analyzed as a function of the state of the deep trap at 730 K. A linear correlation between the TL response of the main dosimetric peak at this band and the occupancy of the said deep trap has been established using the method of stepwise emptying. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The intermediate effect and the diagnostic accuracy in clinical case recall of students and experts in dental medicineEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 3 2009J. Eberhard Abstract Introduction:, The extensive knowledge of experts facilitates the solving of domain-specific problems. In general, this is due to the fact that experts recall more detailed information than do novices or even advanced students. However, if physicians of different expertise levels are asked to write down the details of a given case, advanced medical students recall more information than experts. This phenomenon was called the ,intermediate effect' and is considered to be a specific feature of medical expertise. The aim of the here presented study was to examine this observation in the domain of dental medicine. Materials and methods:, Sixty-one students and 20 specialised dentists participated in this study. Three clinical case descriptions were presented and afterwards the participants were told to write down all concrete information they remembered. Finally, they had to come up with a diagnosis. Interrater agreement, diagnostic accuracy and the recall explanation protocols were analysed statistically in comparison to state-of-the-art (canonical) explanations of the clinical cases. Results:, The mean interrater agreement was 96.2 ± 3.37%. It was shown statistically that the more experienced the participants, the more accurate their diagnoses were (P < 0.001). The statistical analysis using the Games-Howell test demonstrated significant more written recall of the 5th-year students compared with 3rd- and 4th-year students and experts (P < 0.05). Conclusion:, The results of this study suggest the existence of the intermediate effect in clinical case recall in dental medicine and thereby corroborate its importance and general applicability for different medical domains. [source] Signal transducers and activators of transcription 3 signaling pathway.INFLAMMATORY BOWEL DISEASES, Issue 2 2005An Essential Mediator of Inflammatory Bowel Disease, Other Forms of Intestinal Inflammation Abstract Crohn's disease (CD) and ulcerative colitis (UC), the two major forms of chronic inflammatory bowel disease (IBD), are characterized by mucosal immune cell activation that is driven by a cytokine imbalance. Several cytokines involved in IBD act through the activation of the signal transducers and activators of transcription (STAT) family. We investigated the activation of STAT3 in the mucosa of CD and UC patients, and evaluated whether this event is specific for IBD patients. Using immunofluorescence and immunoblotting, total and phosphorylated STAT3 levels were assessed in biopsy specimens, isolated lamina propria mononuclear cells, and peripheral blood mononuclear cells from patients with CD, UC, other forms of intestinal inflammation, and control subjects. Immunoblotting revealed phosphorylated STAT3 in mucosal biopsy specimens from patients with CD, UC, celiac disease, and acute self-limited colitis, but not in the normal mucosa of control subjects. In IBD patients, STAT3 activation was confined to actively inflamed areas. Accordingly, activated STAT3 was detected in isolated lamina propria mononuclear cells from inflamed IBD tissues, but not in peripheral blood mononuclear cells from control subjects or IBD patients. Immunofluorescence demonstrated that the sources of activated STAT3 were macrophages and T lymphocytes, but not neutrophils. STAT3 activation also was detected in T cells infiltrating the duodenal mucosa of celiac disease patients. We conclude that STAT3 signaling occurs in both CD and UC, where it is strictly confined to areas of active inflammation and is limited to infiltrating macrophages and T cells. The occurrence of STAT3 signaling in other acute and chronic intestinal inflammatory conditions suggests that, rather than a specific feature of IBD, it represents a fundamental signaling pathway that is shared by multiple forms of gut inflammation. [source] Phenotypic Characterization of Early Onset Paget's Disease of Bone Caused by a 27-bp Duplication in the TNFRSF11A Gene,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2003Kiyoshi Nakatsuka Abstract Three different insertion mutations in the TNFRSF11A gene affecting the signal peptide of RANK have been described. An 18-bp duplication at position 84 (84dup18) is associated with the clinical syndrome of familial expansile osteolysis (FEO), whereas a 15-bp duplication at the same site (84dup15) causes the syndrome of expansile skeletal hyperphosphatasia (ESH). Here we report the phenotype of patients harboring a 27-bp duplication at position 75 (75dup27) in RANK. Affected individuals had hearing impairment and tooth loss beginning in the second or third decade. Radiographs of affected bones showed lytic and sclerotic lesions with bony enlargement and deformity. Serum alkaline phosphatase levels were elevated between 2 and 17 times above the normal range. Most patients had pelvic and skull involvement, and all had involvement of the mandible and maxilla. Most patients also had bony enlargement of the small joints of the hands, and one developed hypercalcemia during a period of immobilization. We conclude that the 75dup27 mutation of RANK causes a Paget's disease of bone-like phenotype that is distinct from, but which overlaps with, FEO and ESH. A particularly striking feature was involvement of the mandible and maxilla, but it remains to be seen if this is a specific feature of the 75dup27 mutation until further kindreds with this mutation are reported. [source] Preparing to sit the Royal Australia and New Zealand College of Radiologists Faculty of Radiation Oncology Fellowship Part 2 examination: The value of a workshop including practice and feedbackJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 5 2007S Bydder Summary A workshop has been held annually to help prepare candidates to sit the Royal Australia and New Zealand College of Radiologists Part 2 Faculty of Radiation Oncology examination. This study examined the value of such a course and its component parts and assessed attendees' learning environments. We collected detailed information from participants before and after the training workshop in 2005. A specific feature of this workshop included the use of an examination technique feedback form to facilitate the provision of systematic and comprehensive feedback to individual candidates after mock examination. Participants completed course evaluation forms and a learning environment survey. There were 22 candidate participants. The course and its components of this course were perceived very positively , including the examination technique feedback forms and written advice. Only three of the 24 questions regarding the registrars learning environment had less than 80% favourable responses , two of these questions related to workload. The course design described seems reasonably satisfactory in that it included the components ranked most highly by candidates. We also identified a number of variations that may be useful for future workshops. Although learning environments were generally good, we identified a perceived problem with workloads affecting a significant number of registrars. [source] Poly(glycoamidoamine)s: Cationic glycopolymers for DNA deliveryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2006Theresa M. Reineke Abstract Polymer science is playing an exciting role in inspiring and advancing novel discoveries in the area of genetic drug delivery. Polymeric materials can be synthesized and chemically tailored to bind and compact nucleic acids into viral-like nanoparticles termed polyplexes that can deliver genetic materials into cells. This article highlights our work in this area to synthesize and study a novel class of cationic glycopolymers that we have termed poly(glycoamidoamine)s (PGAAs). The design of these materials has been inspired by many previous works in the literature. Carbohydrate comonomers have been incorporated into these structures to lower the toxicity of the delivery vehicle, and oligoamine moieties have been added to yield a cationic backbone that facilitates strong DNA binding, compaction, cellular uptake, and delivery of genetic material. PGAAs have been designed to vary in the carbohydrate size, the hydroxyl number and stereochemistry, the amine number, and the presence or absence of heterocyclic groups. Through structure,bioactivity studies, we have discovered that these materials are highly biocompatible, and each specific feature plays a large role in the observed delivery efficacy. Such structure,property studies are important for increasing our understanding of how the polymer chemistry affects the biological activity for the clinical development of polymer-based therapeutics. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6895,6908, 2006 [source] Market Orientation, Innovativeness, Product Innovation, and Performance in Small FirmsJOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 2 2004Frans J. H. M. Verhees Most research on market orientation, innovation and performance is related to big enterprises and small and medium-sized enterprises (SMEs). In this study a model is developed to investigate the combined effect of market orientation and innovativeness on product innovation and company performance, for small firms. A specific feature of our research is that we use an objective measure for product innovation in contrast to the self-reported measures commonly used in research on innovation. To test our model data from 152 rose growers were used. This study's results show that the owner's innovativeness permeates all variables in the model and has a positive influence on market orientation, innovation, and performance. An interesting research result is also that customer market intelligence influences product innovation positively or negatively, depending on whether the innovativeness of the owner in the new product domain is weak or strong. [source] Is Neoclassical Economics still Entrepreneurless?KYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 3 2005Milo Bianchi Summary The paper reviews and evaluates some recent contributions on modeling entrepreneurship within a neoclassical framework, analyzing how, and to what extent, the fundamental ingredients suggested in the social science literature were captured. It is shown how these approaches are important in stressing the main elements of a complex picture, without being able to fully describe it. Each modeling attempt focuses only on one specific feature of entrepreneurship, and the entrepreneurial function, broadly perceived, eludes analytical tractability. As a consequence, the models can be useful in analyzing the effect of entrepreneurial behavior at an aggregate level, but not at explaining individual choices. From these observations, it is highlighted how a simplistic interpretation of the existing mainstream approaches incorporating entrepreneurship runs the risk of leading to distortionary policy interventions. [source] Morphological and Molecular Characterization of a New Protist Family, Sandmanniellidae n. fam. (Ciliophora, Colpodea), with Description of Sandmanniella terricola n. g., n. sp. from the Chobe Floodplain in BotswanaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 5 2009WILHELM FOISSNER ABSTRACT. Sandmanniella terricola n. g., n. sp. was discovered in soil from the Chobe floodplain, Botswana, southern Africa. Its morphology and 18S rDNA gene sequence were studied with standard methods. Sandmanniella terricola is very likely an adversity strategist because it reaches peak abundances 6,12 h after rewetting the soil and maintains trophic food vacuoles with undigested bacteria in the resting cyst, a highly specific feature suggested as an indicator for an adversity life strategy. Possibly, the energy of the stored food vacuoles is used for reproduction and support of the cyst wall. Morphologically, Sandmanniella terricola is inconspicuous, having a size of only 50 × 40 ,m and a simple, ellipsoidal shape. The main characteristics of the genus are a colpodid silverline pattern; a perioral cilia condensation; a flat, dish-shaped oral cavity, in the centre of which originates a long, conical oral basket resembling that of certain nassulid ciliates; and a vertically oriented left oral polykinetid composed of brick-shaped adoral organelles. This unique mixture of features and the gene sequence trees, where Sandmanniella shows an isolated position, suggest establishing a new family, the Sandmanniellidae n. fam., possibly related to the families Colpodidae or Bryophryidae. The curious oral basket provides some support for the hypothesis of a common ancestor of colpodid and nassulid ciliates. [source] Bracovirus gene products are highly divergent from insect proteinsARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2008Annie Bézier Abstract Recently, several polydnavirus (PDV) genomes have been completely sequenced. The dsDNA circles enclosed in virus particles and injected by wasps into caterpillars appear to mainly encode virulence factors potentially involved in altering host immunity and/or development, thereby allowing the survival of the parasitoid larvae within the host tissues. Parasitoid wasps generally inject virulence factors produced in the venom gland. As PDV genomes are inherited vertically by wasps through a proviral form, wasp virulence genes may have been transferred to this chromosomal form, leading to their incorporation into virus particles. Indeed, many gene products from Cotesia congregata bracovirus (CcBV), such as PTPs, I,B-like, and cystatins, contain protein domains conserved in metazoans. Surprisingly however, CcBV virulence gene products are not more closely related to insect proteins than to human proteins. To determine whether the distance between CcBV and insect proteins is a specific feature of BV proteins or simply reflects a general high divergence of parasitoid wasp products, which might be due to parasitic lifestyle, we have analyzed the sequences of wasp genes obtained from a cDNA library. Wasp sequences having a high similarity with Apis mellifera genes involved in a variety of biological functions could be identified indicating that the high level of divergence observed for BV products is a hallmark of these viral proteins. We discuss how this divergence might be explained in the context of the current hypotheses on the origin and evolution of wasp-bracovirus associations. Arch. Insect Biochem. Physiol. 67:172,187, 2008. © 2008 Wiley-Liss, Inc. [source] Toward a Pluralist Account of ParenthoodBIOETHICS, Issue 3 2003Tim Bayne What is it that makes someone a parent? Many writers , call them ,monists', claim that parenthood is grounded solely in one essential feature that is both necessary and sufficient for someone's being a parent. We reject not only monism but also ,necessity' views, in which some specific feature is necessary but not also sufficient for parenthood. Our argument supports what we call ,pluralism', the view that any one of several kinds of relationship is sufficient for parenthood. We begin by challenging monistic versions of gestationalism, the view that gestation uniquely grounds parenthood. Monistic and necessity gestationalism are implausible. First, we raise the ,paternity problem', necessity gestationalists lack an adequate account of how men become fathers. Second, the positive arguments that necessity gestationalists give are not compelling. However, although gestation may not be a necessary condition for parenthood, there is good reason to think that it is sufficient. After further rebutting an ,intentionalist' account of parenthood, in which having and acting on intentions to procreate and rear is necessary for parenthood, we end by sketching a pluralist picture of the nature of parenthood, rooted in causation, on which gestation, direct genetic derivation, extended custody, and even, sometimes, intentions, may be individually sufficient for parenthood. [source] A New Pyridine-2,6-bis(oxazoline) for Efficient and Flexible Lanthanide-Based Catalysts of Enantioselective Reactions with 3-Alkenoyl-2-oxazolidinonesCHEMISTRY - A EUROPEAN JOURNAL, Issue 13 2005Giovanni Desimoni Prof. Abstract A new pyridine-2,6-bis(oxazoline) (4) has been easily synthesised from the reaction of (1S,2S)-2-amino-1-phenylpropane-1,3-diol (1) and dimethyl pyridine-2,6-dicarboximidate (2), followed by TIPS (TIPS=triisopropylsilyl) protection of the 4,-CH2OH group. The catalysts derived from 4 and eight lanthanide(III) triflates have been tested over three reactions involving 3-acryloyl- and 3-crotonoyloxazolidinones (5,a,b): the Diels,Alder (DA) reaction with cyclopentadiene, the 1,3-dipolar cycloaddition with diphenyl nitrone and the Mukaiyama,Michael reaction with 2-trimethylsilyloxyfuran. Several reactions exhibit very good enantioselectivity (ee>90,%), and the opposite enantiomers can be easily obtained simply by changing the cation. This specific feature of the ligand can be appreciated in the DA reaction of 5,a, since the catalyst [ScIII(4)] gives the adduct (2,S)- 9,a with 99,% ee, whereas the catalyst [YIII(4)] gives the opposite enantiomer with 95,% ee. A rationale of the enantioselectivity is proposed on the basis of the NMR spectra of La-based complexes involving 4 and 5 as ligands. [source] LazyBrush: Flexible Painting Tool for Hand-drawn CartoonsCOMPUTER GRAPHICS FORUM, Issue 2 2009Daniel Sýkora Abstract In this paper we present LazyBrush, a novel interactive tool for painting hand-made cartoon drawings and animations. Its key advantage is simplicity and flexibility. As opposed to previous custom tailored approaches [SBv05, QWH06] LazyBrush does not rely on style specific features such as homogenous regions or pattern continuity yet still offers comparable or even less manual effort for a broad class of drawing styles. In addition to this, it is not sensitive to imprecise placement of color strokes which makes painting less tedious and brings significant time savings in the context cartoon animation. LazyBrush originally stems from requirements analysis carried out with professional ink-and-paint illustrators who established a list of useful features for an ideal painting tool. We incorporate this list into an optimization framework leading to a variant of Potts energy with several interesting theoretical properties. We show how to minimize it efficiently and demonstrate its usefulness in various practical scenarios including the ink-and-paint production pipeline. [source] Illustrative Hybrid Visualization and Exploration of Anatomical and Functional Brain DataCOMPUTER GRAPHICS FORUM, Issue 3 2008W. M. Jainek Abstract Common practice in brain research and brain surgery involves the multi-modal acquisition of brain anatomy and brain activation data. These highly complex three-dimensional data have to be displayed simultaneously in order to convey spatial relationships. Unique challenges in information and interaction design have to be solved in order to keep the visualization sufficiently complete and uncluttered at the same time. The visualization method presented in this paper addresses these issues by using a hybrid combination of polygonal rendering of brain structures and direct volume rendering of activation data. Advanced rendering techniques including illustrative display styles and ambient occlusion calculations enhance the clarity of the visual output. The presented rendering pipeline produces real-time frame rates and offers a high degree of configurability. Newly designed interaction and measurement tools are provided, which enable the user to explore the data at large, but also to inspect specific features closely. We demonstrate the system in the context of a cognitive neurosciences dataset. An initial informal evaluation shows that our visualization method is deemed useful for clinical research. [source] Audit Review: Managers' Interpersonal Expectations and Conduct of the Review,CONTEMPORARY ACCOUNTING RESEARCH, Issue 3 2002Michael Gibbins Abstract This paper presents an interpersonal model of audit file review centered on the audit manager. A manager's conduct of the review is affected by four components: the manager's expectations about the client, expectations about the preparer, expectations about the partner, and the manager's own approach and circumstances. The paper then presents a comprehensive field-based analysis of how a working paper review is conducted. It supplements the mostly experimental research on working paper review by reporting the results of a retrospective field questionnaire that asked audit managers to report on their behavior and their relationships with preparers and partners on actual audit engagements. The extent of review was sensitive to specific features of the client and the file (including risk factors), to features of the preparer, and particularly to the style of the reviewer, which was quite stable across cases. Although the evidence of managers' awareness of preparers' "stylizing" the file to suit the manager was weak, the evidence of managers' stylizing for the partners was pervasive, affecting both work done and documentation. Managers believed that good reviews emphasized key issues and risks rather than detail. Other new descriptive evidence on the nature of the review process is provided, including the purpose of the review process, how frequently surprises are found in the review process, and the qualities of good reviewers compared with poor reviewers. The implications of our model and our results for future research are outlined. [source] Generalized Spitzer Function with Finite Collisionality in Toroidal PlasmasCONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2010W. Kernbichler Abstract The drift kinetic equation solver NEO-2 [1] which is based on the field line integration technique has been applied to compute the generalized Spitzer function in a tokamak with finite plasma collisionality. The resulting generalized Spitzer function has specific features which are pertinent to the finite plasma collisionality. They are absent in asymptotic (collisionless or highly collisional) regimes or in results drawn from interpolation between asymptotic limits. These features have the potential to improve the overall ECCD efficiency if one optimizes the microwave beam launch scenarii accordingly (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The Impact of AIDS on Rural Households in Africa: A Shock Like Any Other?DEVELOPMENT AND CHANGE, Issue 4 2002Carolyn Baylies In areas where HIV prevalence is high, household production can be significantly affected and the integrity of households compromised. Yet policy responses to the impact of HIV/AIDS have been muted in comparison to outcomes of other shocks, such as drought or complex political emergencies. This article looks at the reasons for the apparent under,reaction to AIDS, using data from Zambia, and examines recent calls to mitigate the effects of AIDS at household level. Critical consideration is directed at proposals relating to community safety nets, micro,finance and the mainstreaming of AIDS within larger poverty alleviation programmes. It is argued that effective initiatives must attend to the specific features of AIDS, incorporating both an assault on those inequalities which drive the epidemic and sensitivity to the staging of AIDS both across and within households. A multi,pronged approach is advocated which is addressed not just at mitigation or prevention, but also at emergency relief, rehabilitation and development. [source] Drosophila multiplexin (Dmp) modulates motor axon pathfinding accuracyDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2009Frauke Meyer Multiplexins are multidomain collagens typically composed of an N-terminal thrombospondin-related domain, an interrupted triple helix and a C-terminal endostatin domain. They feature a clear regulatory function in the development of different tissues, which is chiefly conveyed by the endostatin domain. This domain can be found in proteolytically released monomeric and trimeric versions, and their diverse and opposed effects on the migratory behavior of epithelial and endothelial cell types have been demonstrated in cell culture experiments. The only Drosophila multiplexin displays specific features of both vertebrate multiplexins, collagens XV and XVIII. We characterized the Drosophila multiplexin (dmp) gene and found that three main isoforms are expressed from it, one of which is the monomeric endostatin version. Generation of dmp deletion alleles revealed that Dmp plays a role in motor axon pathfinding, as the mutants exhibit ventral bypass defects of the intersegmental nerve b (ISNb) similar to other motor axon guidance mutants. Transgenic overexpression of monomeric endostatin as well as of full-length Dmp, but not trimeric endostatin, were able to rescue these defects. In contrast, trimeric endostatin increased axon pathfinding accuracy in wild type background. We conclude that Dmp plays a modulating role in motor axon pathfinding and may be part of a buffering system that functions to avoid innervation errors. [source] REVIEW: Behavioural assessment of drug reinforcement and addictive features in rodents: an overviewADDICTION BIOLOGY, Issue 1 2006Carles Sanchis-Segura ABSTRACT Some psychoactive drugs are abused because of their ability to act as reinforcers. As a consequence behavioural patterns (such as drug-seeking/drug-taking behaviours) are promoted that ensure further drug consumption. After prolonged drug self-administration, some individuals lose control over their behaviour so that these drug-seeking/taking behaviours become compulsive, pervading almost all life activities and precipitating the loss of social compatibility. Thus, the syndrome of addictive behaviour is qualitatively different from controlled drug consumption. Drug-induced reinforcement can be assessed directly in laboratory animals by either operant or non-operant self-administration methods, by classical conditioning-based paradigms such as conditioned place preference or sign tracking, by facilitation of intracranial electric self-stimulation, or, alternatively by drug-induced memory enhancement. In contrast, addiction cannot be modelled in animals, at least as a whole, within the constraints of the laboratory. However, various procedures have been proposed as possible rodent analogues of addiction's major elements including compulsive drug seeking, relapse, loss of control/impulsivity, and continued drug consumption despite negative consequences. This review provides an extensive overview and a critical evaluation of the methods currently used for studying drug-induced reinforcement as well as specific features of addictive behaviour. In addition, comic strips that illustrate behavioural methods used in the drug abuse field are provided given for free download under http://www.zi-mannheim/psychopharmacology.de [source] Comparison of spatial integration and surround suppression characteristics in spiking activity and the local field potential in macaque V1EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008M. A. Gieselmann Abstract Neurons in primary visual cortex exhibit well documented centre,surround receptive field organization, whereby the centre is dominated by excitatory influences and the surround is generally dominated by inhibitory influences. These effects have largely been established by measuring the output of neurons, i.e. their spiking activity. How excitation and inhibition are reflected in the local field potential (LFP) is little understood. As this can bear on the interpretation of human fMRI BOLD data and on our understanding of the mechanisms of local field potential oscillations, we measured spatial integration and centre,surround properties in single- and multiunit recordings of V1 in the awake fixating macaque monkey, and compared these to spectral power in different frequency bands of simultaneously recorded LFPs. We quantified centre,surround organization by determining the size of the summation and suppression area in spiking activity as well as in different frequency bands of the LFP, with the main focus on the gamma band. Gratings extending beyond the summation area usually inhibited spiking activity while the LFP gamma-band activity increased monotonically for all grating sizes. This increase was maximal for stimuli infringing upon the near classical receptive field surround, where suppression started to dominate spiking activity. Thus, suppressive influences in primary cortex can be inferred from spiking activity, but they also seem to affect specific features of gamma-band LFP activity. [source] Phase Diagrams and Glass Formation in Metallic Systems,ADVANCED ENGINEERING MATERIALS, Issue 6 2007M. Baricco Abstract The basic thermodynamic aspects of glass-formation in metallic systems are reviewed. In particular, the specific features of a phase diagram with respect to glass-formation are evidenced. On the basis of the regular solution model, the effect of various thermodynamic quantities on the free energy difference between undercooled liquid and crystal phases are outlined. In order to describe the amorphous phase, a specific heat difference between liquid and solid phases in the undercooling regime is introduced in the CALPHAD assessment of various binary systems. The glass-transition is described as a second order transition. Examples are given for different systems, including Fe-B and Cu-Mg. From the description of the free energy of various phases as a function of composition and temperature, the driving forces for nucleation of crystal phases and the T0 curves are estimated. [source] Structural and thermodynamic insights into the binding mode of five novel inhibitors of lumazine synthase from Mycobacterium tuberculosisFEBS JOURNAL, Issue 20 2006Ekaterina Morgunova Recently published genomic investigations of the human pathogen Mycobacterium tuberculosis have revealed that genes coding the proteins involved in riboflavin biosynthesis are essential for the growth of the organism. Because the enzymes involved in cofactor biosynthesis pathways are not present in humans, they appear to be promising candidates for the development of therapeutic drugs. The substituted purinetrione compounds have demonstrated high affinity and specificity to lumazine synthase, which catalyzes the penultimate step of riboflavin biosynthesis in bacteria and plants. The structure of M. tuberculosis lumazine synthase in complex with five different inhibitor compounds is presented, together with studies of the binding reactions by isothermal titration calorimetry. The inhibitors showed the association constants in the micromolar range. The analysis of the structures demonstrated the specific features of the binding of different inhibitors. The comparison of the structures and binding modes of five different inhibitors allows us to propose the ribitylpurinetrione compounds with C4,C5 alkylphosphate chains as most promising leads for further development of therapeutic drugs against M. tuberculosis. [source] Nanowires: A General Electrochemical Strategy for Synthesizing Charge-Transfer Complex Micro/Nanowires (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Mater. A general electrochemical strategy for synthesizing charge-transfer complex micro-/nanowires utilizing a carbon nanotube (CNT) electrode is demonstrated by Z. Liu and co-workers on page 1209. The background scanning electron microscopy image depicts high-quality AgTCNQ nanowires grown from a CNT electrode. The uniform and high-aspect-ratio nature of thus-grown charge-transfer complex micro-/nanowires intrinsically originates from the specific features of CNTs in terms of one-dimensional structure and ultrasmall surface area with few or no defects. [source] Feature removal and isolation in potential field dataGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2004F. Boschetti SUMMARY With the aim of designing signal processing tools that act locally in space upon specific features of a signal, we compare two algorithms to remove or isolate individual anomalies in potential field profiles. The first method, based on multiscale edge analysis, leaves other features in the signal relatively untouched. A second method, based on iterative lateral continuation and subtraction of anomalies, accounts for the influence of adjacent anomalies on one another. This allows a potential field profile to be transformed into a number of single anomaly signals. Each single anomaly can then be individually processed, which considerably simplifies applications such as inversion and signal processing. [source] Recurrent Peptic Ulcers in Patients Following Successful Helicobacter pylori Eradication: A Multicenter Study of 4940 PatientsHELICOBACTER, Issue 1 2004Hiroto Miwa ABSTRACT Objective., Although curative treatment of Helicobacter pylori infection markedly reduces the relapse of peptic ulcers, the details of the ulcers that do recur is not well characterized. The aim of this study is to describe the recurrence rate and specific features of peptic ulcers after cure of H. pylori infection. Methods., This was a multicenter study involving 4940 peptic ulcer patients who were H. pylori negative after successful eradication treatment and were followed for up to 48 months. The annual incidence of ulcer relapse in H. pylori -cured patients, background of patients with relapsed ulcers, time to relapse, ulcer size, and site of relapsed ulcers were investigated. Results., Crude peptic ulcer recurrence rate was 3.02% (149/4940). The annual recurrence rates of gastric, duodenal and gastroduodenal ulcer were 2.3%, 1.6%, and 1.6%, respectively. Exclusion of patients who took NSAIDs led annual recurrence rates to 1.9%, 1.5% and 1.3%, respectively. The recurrence rate was significantly higher in gastric ulcer. Recurrence rates of patients who smoked, consumed alcohol, and used NSAIDs were significantly higher in those with gastric ulcer recurrence compared to duodenal ulcer recurrence (e.g. 125 of 149 [83.9%] relapsed ulcers recurred at the same or adjacent sites as the previous ulcers). Conclusions., Curative treatment of H. pylori infection is useful in preventing ulcer recurrence. Gastric ulcer is more likely to relapse than duodenal ulcer. Recurrent ulcer tended to recur at the site of the original ulcers. [source] Functional brain mapping during free viewing of natural scenesHUMAN BRAIN MAPPING, Issue 2 2004Andreas Bartels Abstract Previous imaging studies have used mostly perceptually abstracted, idealized, or static stimuli to show segregation of function in the cerebral cortex. We wanted to learn whether functional segregation is maintained during more natural, complex, and dynamic conditions when many features have to be processed simultaneously, and identify regions whose activity correlates with the perception of specific features. To achieve this, we used functional magnetic resonance imaging (fMRI) to measure brain activity when human observers viewed freely dynamic natural scenes (a James Bond movie). The intensity with which they perceived different features (color, faces, language, and human bodies) was assessed psychometrically in separate sessions. In all subjects different features were perceived with a high degree of independence over time. We found that the perception of each feature correlated with activity in separate, specialized areas whose activity also varied independently. We conclude that even in natural conditions, when many features have to be processed simultaneously, functional specialization is preserved. Our method thus opens a new way of brain mapping, which allows the localization of a multitude of brain areas based on a single experiment using uncontrolled, natural stimuli. Furthermore, our results show that the intensity of activity in a specialized area is linearly correlated with the intensity of its perceptual experience. This leads us to suggest that each specialized area is directly responsible for the creation of a feature-specific conscious percept (a microconsciousness). Hum. Brain Mapp. 21:75,83, 2004. © 2003 Wiley-Liss, Inc. [source] In silico analysis of missense substitutions using sequence-alignment based methods,HUMAN MUTATION, Issue 11 2008Sean V. Tavtigian Abstract Genetic testing for mutations in high-risk cancer susceptibility genes often reveals missense substitutions that are not easily classified as pathogenic or neutral. Among the methods that can help in their classification are computational analyses. Predictions of pathogenic vs. neutral, or the probability that a variant is pathogenic, can be made based on: 1) inferences from evolutionary conservation using protein multiple sequence alignments (PMSAs) of the gene of interest for almost any missense sequence variant; and 2) for many variants, structural features of wild-type and variant proteins. These in silico methods have improved considerably in recent years. In this work, we review and/or make suggestions with respect to: 1) the rationale for using in silico methods to help predict the consequences of missense variants; 2) important aspects of creating PMSAs that are informative for classification; 3) specific features of algorithms that have been used for classification of clinically-observed variants; 4) validation studies demonstrating that computational analyses can have predictive values (PVs) of ,75 to 95%; 5) current limitations of data sets and algorithms that need to be addressed to improve the computational classifiers; and 6) how in silico algorithms can be a part of the "integrated analysis" of multiple lines of evidence to help classify variants. We conclude that carefully validated computational algorithms, in the context of other evidence, can be an important tool for classification of missense variants. Hum Mutat 29(11), 1327,1336, 2008. © 2008 Wiley-Liss, Inc. [source] The cells of the rabbit meniscus: their arrangement, interrelationship, morphological variations and cytoarchitectureJOURNAL OF ANATOMY, Issue 5 2000MARIE-PIERRE HELLIO LE GRAVERAND Four major morphologically distinct classes of cells were identified within the adult rabbit meniscus using antibodies to cytoskeletal proteins. Two classes of cell were present in the fibrocartilage region of the meniscus. These meniscal cells exhibited long cellular processes that extended from the cell body. A third cell type found in the inner hyaline-like region of the meniscus had a rounded form and lacked projections. A fourth cell type with a fusiform shape and no cytoplasmic projections was found along the superficial regions of the meniscus. Using a monoclonal antibody to connexin 43, numerous gap junctions were observed in the fibrocartilage region, whereas none were seen in cells either from the hyaline-like or the superficial zones of the meniscus. The majority of the cells within the meniscus exhibited other specific features such as primary cilia and 2 centrosomes. The placement of the meniscal cell subtypes as well as their morphology and architecture support the supposition that their specific characteristics underlie the ability of the meniscus to respond to different types of environmental mechanical loads. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||