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Basic Functions (basic + function)
Selected AbstractsDirect B -Alkyl Suzuki,Miyaura Cross-Coupling of Trialkyl- boranes with Aryl Bromides in the Presence of Unmasked Acidic or Basic Functions and Base-Labile Protections under Mild Non-Aqueous ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Bing Wang Abstract An efficient and chemoselective palladium-catalyzed direct B -alkyl Suzuki,Miyaura cross-coupling of trialkylboranes with diversely functionalized aryl bromides is described. A wide variety of unmasked acidic or basic functions are tolerated. The mild non-aqueous conditions are compatible with aldehydes, ketones, nitriles, chloro substitution as well as base-labile phenolic Piv and TBS protecting groups. The anhydrous conditions were found to be advantageous for aryl bromide substrates. A potent CEPT inhibitor was efficiently synthesised using this protocol. [source] Allosteric properties of hemoglobin and the plasma membrane of the erythrocyte: New insights in gas transport and metabolic modulationIUBMB LIFE, Issue 2 2008Maria Cristina De Rosa Abstract Within the red blood cell the hemoglobin molecule is subjected to modulation mechanisms, namely homo- and heterotropic interactions, which optimize its functional behavior to the specific physiological requirements. At the cellular level, these modulation mechanisms are utilized to perform a number of other functions that are not minor with respect to the basic function of oxygen transport. Here we report some key examples concerning: (i) the interaction of hemoglobin with band 3 and its influence on glucose metabolism; (ii) the role of the ligand-linked quaternary transition of hemoglobin in the control of "NO bioactivity" and of gas diffusion; (iii) the interaction of plasma membrane with the various oxidative derivatives of the hemoglobin molecule. © 2008 IUBMB IUBMB Life, 60(2): 87,93, 2008 [source] Eukaryotic ribosomal proteins lacking a eubacterial counterpart: important players in ribosomal functionMOLECULAR MICROBIOLOGY, Issue 6 2006John Dresios Summary The ribosome is a macromolecular machine responsible for protein synthesis in all organisms. Despite the enormous progress in studies on the structure and function of prokaryotic ribosomes, the respective molecular details of the mechanism by which the eukaryotic ribosome and associated factors construct a polypeptide accurately and rapidly still remain largely unexplored. Eukaryotic ribosomes possess more RNA and a higher number of proteins than eubacterial ribosomes. As the tertiary structure and basic function of the ribosomes are conserved, what is the contribution of these additional elements? Elucidation of the role of these components should provide clues to the mechanisms of translation in eukaryotes and help unravel the molecular mechanisms underlying the differences between eukaryotic and eubacterial ribosomes. This article focuses on a class of eukaryotic ribosomal proteins that do not have a eubacterial homologue. These proteins play substantial roles in ribosomal structure and function, and in mRNA binding and nascent peptide folding. The role of these proteins in human diseases and viral expression, as well as their potential use as targets for antiviral agents is discussed. [source] Does Erectile Tissue Angioarchitecture Modify with Aging?THE JOURNAL OF SEXUAL MEDICINE, Issue 4 2008An Immunohistological, Morphometric Approach ABSTRACT Introduction., Erectile dysfunction is a common problem in aged men; however, which vascular cavernosal alterations occur with age progression remain unclarified. Aim., Using cavernosal tissue from rats of various ages, we aimed to thoroughly assess erectile vascular-associated morphologic, immunohistological, and morphometric alterations during aging. Methods., Male Wistar rats were divided according to age in groups of 2, 6, 12, 18, 24 months old (N = 5). Cavernosal tissue of all groups was collected and processed for morphologic evaluation, immunodetection of ,-smooth muscle actin and von Willebrand factor and morphometric quantification of vascular and smooth muscle cell (SMC) areas. Main Outcome Measures., The morphometric assessment of age-related alterations in cavernosal vascular and SMCs using the ImageJ image-processing program. Results., Morphologic and immunohistological evaluation showed a similar structure of erectile tissue among all age groups, divided in two cavernosal bodies containing numerous sinusoidal vascular spaces surrounded by SMCs. Additionally, we observed a reduction of SMC content and an increase in the caliber of vascular spaces, with aging. This was confirmed by the morphometric quantification of the vascular and SMC areas (mean area ×103 µm2 ± ×103 standard error). Two-month-old animals had a mean vascular area of 4.21 ± 0.51, approximately 3.5-fold less than the 6-month-old group. The differences increased when comparing the youngest groups with the 12-, 18-, and 24-month-old animals, with mean measurements of 18.99 ± 1.91, 25.23 ± 2.76, and 26.34 ± 2.97. Conversely, SMC areas progressively decreased between 2- and 6-month-old animals, from 6.75 ± 0.90 to 6.38 ± 1.24. The elderly 12-, 18-, and 24-month-old groups presented an approximated 1.5-fold reduction on SMCs area, showed by the respective measurements of 4.11 ± 0.50, 4.01 ± 0.35, and 4.02 ± 0.44. Conclusions., We demonstrated that cavernosal angioarchitecture was modified with aging. The decrease in SMCs and the considerable enlargement of vascular lumens may limit the basic function of penile vascular tree in the elderly. Costa C, and Vendeira P. Does erectile tissue angioarchitecture modify with aging? An immunohistological and morphometric approach. J Sex Med 2008;5:833,840. [source] The role of ,-acidic and ,-basic chiral stationary phases in the high-performance liquid chromatographic enantioseparation of unusual ,-amino acidsCHIRALITY, Issue 3 2009István Ilisz Abstract The application of 3,5-dimethylphenyl-carbamoylated-,-cyclodextrin (Cyclobond I 2000 DMP) and 2,6-dinitro-4-trifluoromethylphenyl-ether-,-cyclodextrin-based (Cyclobond DNP) chiral stationary phases for the high-performance liquid chromatographic enantioseparation of unusual ,-amino acids is reported. The investigated amino acids were saturated or unsaturated alicyclic ,-3-homo-amino acids and bicyclic ,-amino acids. Prior to chromatographic analyses, all amino acids were transformed to N- 3,5-dinitrobenzoyl- or N -3,5-dimethylbenzoyl form to ensure a ,-acidic or ,-basic function and to enhance the ,-acidic-,-basic interactions between analytes and chiral selectors. Chromatographic results are given as retention, separation and resolution factors. The chromatographic conditions were varied to achieve optimal separation. The sequence of elution of the enantiomers was determined in some cases. Chirality, 2009. © 2008 Wiley-Liss, Inc. [source] Some Learning Methods in Functional NetworksCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2000Enrique Castillo This article is devoted to learning functional networks. After a short introduction and motivation of functional networks using a CAD problem, four steps used in learning functional networks are described: (1) selection of the initial topology of the network, which is derived from the physical properties of the problem being modeled, (2) simplification of this topology, using functional equations, (3) estimation of the parameters or weights, using least squares and minimax methods, and (4) selection of the subset of basic functions leading to the best fit to the available data, using the minimum-description-length principle. Several examples are presented to illustrate the learning procedure, including the use of a separable functional network to recover the missing data of the significant wave height records in two different locations, based on a complete record from a third location where the record is complete. [source] Genetic manipulation, whole-cell recordings and functional imaging of the sensorimotor cortex of behaving miceACTA PHYSIOLOGICA, Issue 1 2009C. C. H. Petersen Abstract Sensory processing, sensorimotor integration and motor control are amongst the most basic functions of the brain and yet our understanding of how the underlying neuronal networks operate and contribute to behaviour is very limited. The relative simplicity of the mouse whisker sensorimotor system is helpful for detailed quantitative analyses of motor control and perception during active sensory processing. Recent technical advances now allow the measurement of membrane potential in awake-behaving mice, using whole-cell recordings and voltage-sensitive dye imaging. With these recording techniques, it is possible to directly correlate neuronal activity with behaviour. However, in order to obtain causal evidence for the specific contributions of different neuronal networks to behaviour, it is critical to manipulate the system in a highly controlled manner. Advances in molecular neurobiology, gene delivery and mouse genetics provide techniques capable of layer, column and cell-type specific control of gene expression in the mouse neocortex. Over the next years, we anticipate considerable advances in our understanding of brain function through measuring and manipulating neuronal activity with unprecedented precision to probe the molecular and synaptic mechanisms underlying simple forms of active sensory perception and associative learning. [source] The lateral intercellular space as osmotic coupling compartment in isotonic transportACTA PHYSIOLOGICA, Issue 1 2009E. H. Larsen Abstract Solute-coupled water transport and isotonic transport are basic functions of low- and high-resistance epithelia. These functions are studied with the epithelium bathed on the two sides with physiological saline of similar composition. Hence, at transepithelial equilibrium water enters the epithelial cells from both sides, and with the reflection coefficient of tight junction being larger than that of the interspace basement membrane, all of the water leaves the epithelium through the interspace basement membrane. The common design of transporting epithelia leads to the theory that an osmotic coupling of water absorption to ion flow is energized by lateral Na+/K+ pumps. We show that the theory accounts quantitatively for steady- and time dependent states of solute-coupled fluid uptake by toad skin epithelium. Our experimental results exclude definitively three alternative theories of epithelial solute,water coupling: stoichiometric coupling at the molecular level by transport proteins like SGLT1, electro-osmosis and a ,junctional fluid transfer mechanism'. Convection-diffusion out of the lateral space constitutes the fundamental problem of isotonic transport by making the emerging fluid hypertonic relative to the fluid in the lateral intercellular space. In the Na+ recirculation theory the ,surplus of solutes' is returned to the lateral space via the cells energized by the lateral Na+/K+ pumps. We show that this theory accounts quantitatively for isotonic and hypotonic transport at transepithelial osmotic equilibrium as observed in toad skin epithelium in vitro. Our conclusions are further developed for discussing their application to solute,solvent coupling in other vertebrate epithelia such as small intestine, proximal tubule of glomerular kidney and gallbladder. Evidence is discussed that the Na+ recirculation theory is not irreconcilable with the wide range of metabolic cost of Na+ transport observed in fluid-transporting epithelia. [source] Simulation of patient encounters using a virtual patient in periodontology instruction of dental students: design, usability, and learning effect in history-taking skillsEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 3 2004M. Schittek Janda Simulations are important educational tools in the development of health care competence. This study describes a virtual learning environment (VLE) for diagnosis and treatment planning in oral health care. The VLE is a web-based, database application where the learner uses free text communication on the screen to interact with patient data. The VLE contains forms for history taking, clinical images, clinical data and X-rays. After reviewing the patient information, the student proposes therapy and makes prognostic evaluations of the case in free text. A usability test of the application was performed with seven dental students. The usability test showed that the software responded with correct answers to the majority of the free text questions. The application is generic in its basic functions and can be adapted to other dental or medical subject areas. A randomised controlled trial was carried out with 39 students who attended instruction in history taking with problem-based learning cases, lectures and seminars. In addition, 16 of the 39 students were randomly chosen to practise history taking using the virtual patient prior to their first patient encounter. The performance of each student was recorded on video during the patient sessions. The type and order of the questions asked by the student and the degree of empathy displayed towards the patient were analysed systematically on the videos. The data indicate that students who also undertook history taking with a virtual patient asked more relevant questions, spent more time on patient issues, and performed a more complete history interview compared with students who had only undergone standard teaching. The students who had worked with the virtual patient also seemed to have more empathy for the patients than the students who had not. The practising of history taking with a virtual patient appears to improve the capability of dental students to take a relevant oral health history. [source] Rescue of ,2 subunit-deficient mice by transgenic overexpression of the GABAA receptor ,2S or ,2L subunit isoformsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2000Kristin Baer Abstract The ,2 subunit is an important functional determinant of GABAA receptors and is essential for formation of high-affinity benzodiazepine binding sites and for synaptic clustering of major GABAA receptor subtypes along with gephyrin. There are two splice variants of the ,2 subunit, ,2 short (,2S) and ,2 long (,2L), the latter carrying in the cytoplasmic domain an additional eight amino acids with a putative phosphorylation site. Here, we show that transgenic mice expressing either the ,2S or ,2L subunit on a ,2 subunit-deficient background are phenotypically indistinguishable from wild-type. They express nearly normal levels of ,2 subunit protein and [3H]flumazenil binding sites. Likewise, the distribution, number and size of GABAA receptor clusters colocalized with gephyrin are similar to wild-type in both juvenile and adult mice. Our results indicate that the two ,2 subunit splice variants can substitute for each other and fulfil the basic functions of GABAA receptors, allowing in vivo studies that address isoform-specific roles in phosphorylation-dependent regulatory mechanisms. [source] Ontogeny of escape swimming performance in the spotted salamanderFUNCTIONAL ECOLOGY, Issue 3 2010Tobias Landberg Summary 1.,The life stage suffering the highest predation rate is expected to have the highest escape performance unless developmental or functional constraints interfere. Peak aquatic escape performance in ephemeral pond-breeding amphibians is expected to develop early in the larval period, and metamorphosis is expected to reduce or completely disrupt aquatic escape performance. In anurans, exceptionally low escape performance during metamorphosis creates selection favouring rapid metamorphosis , which minimizes the time individuals spend in the vulnerable transition between tadpole and frog. 2.,We investigated the development of aquatic escape performance in the spotted salamander, Ambystoma maculatum (Shaw, 1802), from embryonic development through metamorphosis. We expected performance to peak early in the larval period as hatchlings face high rates of predation but embryos must first develop escape behaviours. We also tested whether escape performance during metamorphosis was intermediate, as predicted by tail fin resorption, or lower than larvae and adults indicating a major physiological disruption. 3.,Escape performance shows a complex ontogeny that is first positively influenced by embryonic and early larval development and then negatively correlated with tail resorption and body size. Escape distance was the only performance metric not affected by life stage. In contrast, both escape velocity and duration showed ontogenetic peaks early in the larval period with the lowest performance found in early embryos and adults and intermediate performance during metamorphosis. 4.,This pattern suggests that metamorphosis does not impose a major physiological disruption on escape performance. Because spotted salamanders do not pass through a frog-like ,ontogenetic performance valley' during metamorphosis, they may be less subject than anurans to selection favouring rapid metamorphosis. 5.,Functional implications of phenotypic variation should be considered in an ontogenetic framework because the relationship between body size and escape performance can be reversed on either side of an ontogenetic performance peak. The assumption that metamorphosis radically disrupts basic functions such as predator evasion does not seem universally warranted and suggests examination of ontogenetic performance trajectories in a diversity of animals with complex life cycles. [source] Carbon Nanotubes Carrying Cell-Adhesion Peptides do not Interfere with Neuronal Functionality,ADVANCED MATERIALS, Issue 28 2009Claire Gaillard Water-soluble carbon nanotubes functionalized with cell-adhesion peptides do not affect the viability of different cell types, including Jurkat cells, splenocytes, and neurons. They also do not modify the neuronal morphology and basic functions, thus representing a promising candidate for the exploitation of novel drug-delivery systems or for designing a new generation of self-assembling nerve bridges. [source] Cognitive correlates of brain MRI subcortical signal hyperintensities in non-demented elderlyINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 1 2006Gad A. Marshall Abstract Objective To investigate the relationship between magnetic resonance imaging (MRI) subcortical gray and capsular (SGCH) and white matter hyperintensities (WMH) and cognitive functions in non-demented community dwelling elderly. Methods The severity of SGCH and WMH on proton density and T2 MR images in 16 subjects was scored using the semi-quantitative rating scale of Scheltens et al. (1993). A limited series of cognitive tests selected a priori were then correlated with severity of SGCH and WMH. Results Analysis demonstrated that severity of SGCH was inversely related to performance on the Digit Span (R,=,,0.64, p,<,0.01) and the Stroop Color Word Tests (R,=,,0.64, p,<,0.01). Severity of WMH was related to worsening performance on the Trail Making Test (R,=,0.67, p,<,0.005). Conclusions These findings indicate that severity of WMH is negatively related to more pure executive cognitive functions, specifically set shifting, while severity of SGCH is inversely related to more basic functions of attention and working memory. Copyright © 2005 John Wiley & Sons, Ltd. [source] Direct B -Alkyl Suzuki,Miyaura Cross-Coupling of Trialkyl- boranes with Aryl Bromides in the Presence of Unmasked Acidic or Basic Functions and Base-Labile Protections under Mild Non-Aqueous ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Bing Wang Abstract An efficient and chemoselective palladium-catalyzed direct B -alkyl Suzuki,Miyaura cross-coupling of trialkylboranes with diversely functionalized aryl bromides is described. A wide variety of unmasked acidic or basic functions are tolerated. The mild non-aqueous conditions are compatible with aldehydes, ketones, nitriles, chloro substitution as well as base-labile phenolic Piv and TBS protecting groups. The anhydrous conditions were found to be advantageous for aryl bromide substrates. A potent CEPT inhibitor was efficiently synthesised using this protocol. [source] Between Xylem and Phloem: The Genetic Control of Cambial Activity in PlantsPLANT BIOLOGY, Issue 5 2003Y. Helariutta Abstract: Post-embryonic development is controlled by two types of meristems: apical and lateral. There has been considerable progress recently in understanding the function of root and shoot apical meristems at the molecular level. Knowledge of analogous processes in the lateral, or secondary, meristems, i.e. the vascular cambium or cork cambium, is, however, rudimentary. This is despite the fact that much of the diversity in the plant kingdom is based on the differential functions of these meristems, emphasizing the importance of lateral meristems in the development of different plant forms. The vascular cambium is particularly important for woody plants, but it also plays an important role during the development of various herbaceous species, such as Arabidopsis thaliana. In this review, we focus on the two basic functions of cambial activity: cell proliferation and pattern formation. [source] Discovering functions and revealing mechanisms at molecular level from biological networksPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 16 2007Shihua Zhang Abstract With the increasingly accumulated data from high-throughput technologies, study on biomolecular networks has become one of key focuses in systems biology and bioinformatics. In particular, various types of molecular networks (e.g., protein,protein interaction (PPI) network; gene regulatory network (GRN); metabolic network (MN); gene coexpression network (GCEN)) have been extensively investigated, and those studies demonstrate great potentials to discover basic functions and to reveal essential mechanisms for various biological phenomena, by understanding biological systems not at individual component level but at a system-wide level. Recent studies on networks have created very prolific researches on many aspects of living organisms. In this paper, we aim to review the recent developments on topics related to molecular networks in a comprehensive manner, with the special emphasis on the computational aspect. The contents of the survey cover global topological properties and local structural characteristics, network motifs, network comparison and query, detection of functional modules and network motifs, function prediction from network analysis, inferring molecular networks from biological data as well as representative databases and software tools. [source] Platelets Influence Vascularized Organ Transplants from Start to FinishAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2009A. D. Kirk This review relates the basic functions of platelets to specific aspects of organ allograft rejection. Platelet activation can occur in the donor or recipient before transplantation as well as during antibody- and cell-mediated rejection. Biopsies taken during organ procurement from cadaver donors have documented that activated platelets are attached to vascular endothelial cells or leukocytes. In addition, many patients waiting for transplants have activated platelets due to the diseases that lead to organ failure or as a result of interventions used to support patients before and during transplantation. The contribution of platelets to hyperacute rejection of both allografts and xenografts is well recognized. Intravascular aggregates of platelets can also be prominent in experimental and clinical transplants that undergo acute antibody or cell-mediated rejection. In acute rejection, platelets can recruit mononuclear cells by secretion of chemokines. After contact, monocytes, macrophages and T cells interact with platelets through receptor/ligand pairs, including P-selectin/PSGL-1 and CD40/CD154. There is a potential for therapy to inhibit platelet mediated immune stimulation, but it is counterbalanced by the need to maintain coagulation in the perioperative period. [source] Neuroscience, education and special educationBRITISH JOURNAL OF SPECIAL EDUCATION, Issue 4 2004Usha Goswami The discipline of neuroscience draws from the fields of neurology, psychology, physiology and biology, but is best understood in the wider world as ,brain science'. Of particular interest for education is the development of techniques for ,imaging' the brain as it performs different cognitive functions. Cognitive neuroimaging has already led to advances in understanding some of the basic functions involved in learning and raised implications for education and special education in particular. For example, neuroimaging has enabled scientists to study the very complex processes underpinning speech and language, thinking and reasoning, reading and mathematics. In this article, Professor Usha Goswami of the University of Cambridge Faculty of Education first reviews basic information on brain development. She provides a brief introduction to the tools used in neuroimaging then considers recent findings from neuroscience that seem relevant to educational questions. Professor Goswami uses this review to suggest particular ways in which neuroscience research could inform special education. In its closing sections, this article provides authoritative perspectives on some of the ,neuromyths' that seem to have taken root in the popular imagination and argues for increased dialogue, in the future, between the disciplines of neuroscience and education. [source] Humor as a Double-Edged Sword: Four Functions of Humor in CommunicationCOMMUNICATION THEORY, Issue 3 2000John C. Meyer The compelling power of humor makes it a recurrent topic for research in many fields, including communication. Three theories of humor creation emerge in humor research: the relief theory, which focuses on physiological release of tension; the incongruity theory, singling out violations of a rationally learned pattern; and the superiority theory, involving a sense of victory or triumph. Each theory helps to explain the creation of different aspects of humor, but each runs into problems explaining rhetorical applications of humor. Because each theory of humor origin tries to explain all instances of humor, the diverging communication effects of humor remain unexplained. Humor's enactment leads to 4 basic functions of humor in communication. Two tend to unite communicators: the identification and the clarification functions. The other 2 tend to divide 1 set of communicators from others: the enforcement and differentiation functions. Exploration of these effects-based functions of humor will clarify understanding of its use in messages. Humor use unites communicators through mutual identification and clarification of positions and values, while dividing them through enforcement of norms and differentiation of acceptable versus unacceptable behaviors or people. This paradox in the functions of humor in communication as, alternately, a unifier and divider, allows humor use to delineate social boundaries. [source] | |||||||||||||||||||