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Complex Functions (complex + function)
Selected AbstractsPeriorbital Reconstruction with Adjacent-Tissue Skin GraftsDERMATOLOGIC SURGERY, Issue 12 2005Andrew J. Kaufman MD Background. Reconstruction in the periorbital area is challenging owing to the complex function of the eye, relative lack of adjacent loose tissue, free anatomic margin, central facial location, and the need to maintain symmetry with the contralateral eye. Reconstructive options risk crossing anatomic margins, deviation of the lid margin (ectropion), persistent lymphedema, and repair with skin of dissimilar color, texture, and thickness. Objective. The purpose was to describe a reconstructive option that would avoid crossing cosmetic units or subunits, minimize the risk of ectropion, repair with tissue of similar surface characteristics, and maintain function and symmetry with the contralateral side. Methods. The adjacent-tissue skin graft provides closure in cosmetic units and subunits, avoids tension on the lid margin, and provides similar skin for repair. The procedure is demonstrated by graphic and photographic examples. Results. The procedure provides for esthetic repair of the periorbital area and minimizes the risk of ectropion, lymphedema, asymmetry, and dysfunction of the lids and lacrimal system. Conclusion. Adjacent-tissue skin grafts are a useful alternative for reconstruction of partial-thickness defects on the eyelid and periorbital area. ANDREW J. KAUFMAN, MD, HAS INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. [source] Efficient reduction of fault current through the grounding grid of a substation supplied by an overhead lineEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2006Ljubivoje M. Popovi Abstract The paper presents a directly applicable and reasonably accurate method for the evaluation of the effects of the counterpoise, the measure for the reduction of the fault current through the substation grounding grid. Under practical conditions the magnitude of the current diverted from a substation grounding grid by the counterpoise conductor is a very complex function of the self and mutual impedances of overhead and underground conductors, substation grounding impedance, transmission line towers resistance, proximity effect between the grounding grid and the counterpoise conductor, as well as on many other factors of lower order. Therefore certain idealizations and simplification of the real physical model were indispensable to develop the mathematical model presented here. The obtained expressions are mostly based on the general equations of a line represented by its lumped parameters and the general equations of uniform ladder circuits. Copyright © 2006 John Wiley & Sons, Ltd. [source] Hydrogeologic controls on summer stream temperatures in the McKenzie River basin, OregonHYDROLOGICAL PROCESSES, Issue 24 2007Christina Tague Abstract Stream temperature is a complex function of energy inputs including solar radiation and latent and sensible heat transfer. In streams where groundwater inputs are significant, energy input through advection can also be an important control on stream temperature. For an individual stream reach, models of stream temperature can take advantage of direct measurement or estimation of these energy inputs for a given river channel environment. Understanding spatial patterns of stream temperature at a landscape scale requires predicting how this environment varies through space, and under different atmospheric conditions. At the landscape scale, air temperature is often used as a surrogate for the dominant controls on stream temperature. In this study we show that, in regions where groundwater inputs are key controls and the degree of groundwater input varies in space, air temperature alone is unlikely to explain within-landscape stream temperature patterns. We illustrate how a geologic template can offer insight into landscape-scale patterns of stream temperature and its predictability from air temperature relationships. We focus on variation in stream temperature within headwater streams within the McKenzie River basin in western Oregon. In this region, as in other areas of the Pacific Northwest, fish sensitivity to summer stream temperatures continues to be a pressing environmental issue. We show that, within the McKenzie, streams which are sourced from deeper groundwater reservoirs versus shallow subsurface flow systems have distinct summer temperature regimes. Groundwater streams are colder, less variable and less sensitive to air temperature variation. We use these results from the western Oregon Cascade hydroclimatic regime to illustrate a conceptual framework for developing regional-scale indicators of stream temperature variation that considers the underlying geologic controls on spatial variation, and the relative roles played by energy and water inputs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Time to precept: supportive and limiting conditions for precepting nurses.JOURNAL OF ADVANCED NURSING, Issue 2 2010Elisabeth Carlson carlson e., pilhammar e. & wann-hansson c. (2010) Time to precept: supportive and limiting conditions for precepting nurses. Journal of Advanced Nursing66(2), 432,441. Abstract Title.,Time to precept: supportive and limiting conditions for precepting nurses. Aim., This paper is a report of a study describing conditions for precepting in a Swedish clinical context from the perspective of precepting nurses. Background., Clinical practice is a complex part of nursing education, and registered nurses who are acting as preceptors for nursing students face a number of challenges that need to be addressed during the precepting process. Method., An ethnographic approach guided by symbolic interactionism was used. Data were collected by participant observation and focus group interviews over a ten-month period in 2006,2007. Participants were selected by purposive sampling of 13 staff nurses who were preceptors during the field work period. In addition, 16 staff nurses, experienced in precepting, were purposively selected for four focus groups. Findings., Precepting was found to be a complex function for nurses, influenced by conditions that could be both supportive and limiting in nature. Three themes described these conditions: organization, comprising clinical responsibilities and routines; collaboration, focusing on professional relations and interactions; and the personal perspective, comprising preceptors' experiences, need for feed back and notions of benefits. Time as a limiting condition reappeared through all categories. Conclusion., It is important to raise the issue of time and its impact on the precepting process. Precepting needs to be further discussed in terms of an integrated nursing competence prioritized by all stakeholders involved in clinical practice. Therefore; efforts should be made to plan nurses' clinical work so that allocated time for precepting can be facilitated. [source] Interactions Between Extracellular Stimuli and Excitation Waves in an Atrial Reentrant LoopJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2003CHAD R. JOHNSON B.S.E. Introduction: The interactions between extracellular stimuli and excitation waves propagating in a reentrant loop are a complex function of stimulus parameters, structural properties, membrane state, and timing. Here the goal was a comprehensive understanding of the mechanisms and frequencies of the major interactions between the advancing excitation wave and a single extracellular stimulus, separated from issues of anatomic or geometric complexity. Methods and Results: A modernized computer model of a thin ring of uniform tissue that included a pair of extracellular stimulus electrodes (anode/cathode) was used to model one-dimensional cardiac reentry. Questions and results included the following: (1) What are the major interactions between a stimulus and the reentrant propagation wave, and are they induced near the cathode or near the anode; and, for each interaction, what are the initiating amplitude range and timing interval? At the cathode, the well-known mechanism of retrograde excitation terminated reentry; changes in timing or amplitude produced double-wave reentry or phase reset. At the anode, termination occurred at different cells depending on stimulus amplitude. (2) Relatively how often did termination occur at the anode? For most stimulus amplitudes, termination occurred more often at the anode than at the cathode, although not always at the same cell. (3) With random timing, what is the probability of terminating reentry? Stimulation for 5 msec terminated reentry with a probability from 0% to approximately 10%, as a function of increasing stimulus amplitude. Conclusion: A single extracellular stimulus can initiate major changes in reentrant excitation via multiple mechanisms, even in a simple geometry. Termination of reentry, phase shifts, or double-wave reentry each occurs over well-defined ranges of stimulus amplitude and timing. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***-***, October 2003) [source] Neural network-based state prediction for strategy planning of an air hockey robotJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2001Jung Il Park We analyze a neural network implementation for puck state prediction in robotic air hockey. Unlike previous prediction schemes which used simple dynamic models and continuously updated an intercept state estimate, the neural network predictor uses a complex function, computed with data acquired from various puck trajectories, and makes a single, timely estimate of the final intercept state. Theoretically, the network can account for the complete dynamics of the table if all important state parameters are included as inputs, an accurate data training set of trajectories is used, and the network has an adequate number of internal nodes. To develop our neural networks, we acquired data from 1500 no-bounce and 1500 one-bounce puck trajectories, noting only translational state information. Analysis showed that performance of neural networks designed to predict the results of no-bounce trajectories was better than the performance of neural networks designed for one-bounce trajectories. Since our neural network input parameters did not include rotational puck estimates and recent work shows the importance of spin in impact analysis, we infer that adding a spin input to the neural network will increase the effectiveness of state estimates for the one-bounce case. © 2001 John Wiley & Sons, Inc. [source] Tryptophanyl fluorescence lifetime distribution of hyperthermophilic ,-glycosidase from molecular dynamics simulation: A comparison with the experimental dataPROTEIN SCIENCE, Issue 9 2000Ettore Bismuto Abstract A molecular dynamics simulation approach has been utilized to understand the unusual fluorescence emission decay observed for ,-glycosidase from the hyperthermophilic bacterium Solfolobus sulfataricus (S,gly), a tetrameric enzyme containing 17 tryptophanyl residues for each subunit. The tryptophanyl emission decay of (S,gly) results from a bimodal distribution of fluorescence lifetimes with a short-lived component centered at 2.5 ns and a long-lived one at 7.4 ns Bismuto E, Nucci R, Rossi M, Irace G, 1999, Proteins 27:71,79). From the examination of the trajectories of the side chains capable of causing intramolecular quenching for each tryptophan microenvironment and using a modified Stern,Volmer model for the emission quenching processes, we calculated the fluorescence lifetime for each tryptophanyl residue of S,gly at two different temperatures, i.e., 300 and 365 K. The highest temperature was chosen because in this condition S,lgy evidences a maximum in its catalytic activity and is stable for a very long time. The calculated lifetime distributions overlap those experimentally determined. Moreover, the majority of trytptophanyl residues having longer lifetimes correspond to those originally identified by inspection of the crystallographic structure. The tryptophanyl lifetimes appear to be a complex function of several variables, such as microenvironment viscosity, solvent accessibility, the chemical structure of quencher side chains, and side-chain dynamics. The lifetime calculation by MD simulation can be used to validate a predicted structure by comparing the theoretical data with the experimental fluorescence decay results. [source] Retrovirus-Polymer Complexes: Study of the Factors Affecting the Dose Response of TransductionBIOTECHNOLOGY PROGRESS, Issue 2 2007Natalia Landázuri We have previously shown that complexes of Polybrene (PB), chondroitin sulfate C (CSC), and retrovirus transduce cells more efficiently than uncomplexed virus because the complexes are large and sediment, reaching the cells more rapidly than by diffusion. Transduction reaches a peak at equal weight concentrations of CSC and PB and declines when the dose of PB is higher or lower than CSC. We hypothesized that the nonlinear dose response of transduction was a complex function of the molecular characteristics of the polymers, cell viability, and the number of viruses incorporated into the complexes. To test this hypothesis, we formed complexes using an amphotropic retrovirus and several pairs of oppositely charged polymers and used them to transduce murine fibroblasts. We examined the effect of the type and concentration of polymers used on cell viability, the size and charge of the complexes, the number of viruses incorporated into the complexes, and virus binding and transduction. Transduction was enhanced (2.5- to 5.5-fold) regardless of which polymers were used and was maximized when the number of positive charge groups was in slight excess (15,28%) of the number of negative charge groups. Higher doses of cationic polymer were cytotoxic, whereas complexes formed with lower doses were smaller, contained fewer viruses, and sedimented more slowly. These results show that the dose response of transduction by virus-polymer complexes is nonlinear because excess cationic polymer is cytotoxic, whereas excess anionic polymer reduces the number of active viruses that are delivered to the cells. [source] The Drosophila nucleoporin gene nup154 is required for correct microfilament dynamics and cell death during oogenesisCYTOSKELETON, Issue 8 2007Maria Giovanna Riparbelli Abstract The Drosophila nucleoporin gene nup154 is required in both male and female germline for successful gametogenesis. Mutant flies lack differentiated sperm and lay abnormal eggs. We demonstrated that the egg phenotype was associated with specific alterations of the actin cytoskeleton at different stages of oogenesis. Actually, mutant egg chambers displayed an abnormal organization of both subcortical microfilaments and cytoplasmic actin bundles, that led to defective nurse cell dumping. TUNEL analysis also showed that the dumpless phenotype was associated with delayed apoptosis. The nup154 gene product was localized by conventional immunofluorescence microscopy to the nuclear envelope in a distinct punctuate pattern, characteristic of nuclear pore complex components. TEM analysis revealed that the protein was mainly distributed along filamentous structures that extended radially on the nuclear side of the pore, suggesting that Nup154 could be an integral component of the basket filaments associated with the nuclear pore complexes. We propose that Nup154 is necessary for correct nuclear pore complex functions and that the proper regulation of the actin cytoskeleton dynamics strongly relies upon nuclear pore integrity. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Mi-2 chromatin remodeling factor functions in sensory organ development through proneural gene repression in DrosophilaDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 7 2006Yasutoyo Yamasaki Mi-2, the central component of the nucleosome remodeling and histone deacetylation (NuRD) complex, is known as an SNF2-type ATP-dependent nucleosome remodeling factor. No morphological mutant phenotype of Drosophila Mi-2 (dMi-2) had been reported previously; however, we found that rare escapers develop into adult flies showing an extra bristle phenotype. The dMi-2 enhanced the phenotype of acHw49c, which is a dominant gain-of-function allele of achaete (ac) and produces extra bristles. Consistent with these observations, the ac -expressing proneural clusters were expanded, and extra sensory organ precursors (SOP) were formed in the dMi-2 mutant wing discs. Immunostaining of polytene chromosomes showed that dMi-2 binds to the ac locus, and dMi-2 and acetylated hisotones distribute on polytene chromosomes in a mutually exclusive manner. The chromatin immunoprecipitation assay of the wing imaginal disc also demonstrated a binding of dMi-2 on the ac locus. These results suggest that the Drosophila Mi-2/NuRD complex functions in neuronal differentiation through the repression of proneural gene expression by chromatin remodeling and histone deacetylation. [source] Functional retinoid receptors in budding ascidiansDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2000Mika Kamimura A homolog of retinoid X receptors (RXR), named PmRXR, was cloned from the budding ascidian, Polyandrocarpa misakiensis. Gel-shift assays revealed that PmRXR and a previously identified P. misakiensis retinoic acid receptor (PmRAR) formed a complex to bind vertebrate-type retinoic acid response element (RARE). Transfection assays were carried out using a reporter gene containing a RARE upstream of lacZ. Two chimeric effector genes were constructed by placing PmRXR and PmRAR cDNA fragments (containing the DNA-binding, ligand-binding and ligand-dependent transactivation domains) downstream of the human RXR, and RAR, cDNA (covering the N-terminal coding region), respectively. Each chimeric cDNA was ligated to a notochord-specific enhancer. In case the embryos were transfected with all three transgenes and treated with retinoic acid (RA), the reporter gene was activated in the notochord cells. The result suggests that the PmRXR/PmRAR complex functions as an RA-dependent transcriptional activator. The PmRXR mRNA was detected in a mesenchymal cell type, called glomerulocyte, in the developing Polyandrocarpa bud. As this cell type has been shown to express PmRAR mRNA, it seems possible that the PmRXR/PmRAR complex mediates RA signaling in this cell type to induce the expression of genes involved in the morphogenesis of the developing bud. [source] Drosophila CtBP regulates proliferation and differentiation of eye precursors and complexes with Eyeless, Dachshund, Dan, and Danr during eye and antennal developmentDEVELOPMENTAL DYNAMICS, Issue 9 2010Chinh Q. Hoang Abstract Specification factors regulate cell fate in part by interacting with transcriptional co-regulators like CtBP to regulate gene expression. Here, we demonstrate that CtBP forms a complex or complexes with the Drosophila melanogaster Pax6 homolog Eyeless (Ey), and with Distal antenna (Dan), Distal antenna related (Danr), and Dachshund to promote eye and antennal specification. Phenotypic analysis together with molecular data indicate that CtBP interacts with Ey to prevent overproliferation of eye precursors. In contrast, CtBP,dan,danr triple mutant adult eyes have significantly fewer ommatidia than CtBP single or dan,danr double mutants, suggesting that the CtBP/Dan/Danr complex functions to recruit ommatidia from the eye precursor pool. Furthermore, CtBP single and to a greater extent CtBP,dan,danr triple mutants affect the establishment and maintenance of the R8 precursor, which is the founding ommatidial cell. Thus, CtBP interacts with different eye specification factors to regulate gene expression appropriate for proliferative vs. differentiative stages of eye development. Developmental Dynamics 239:2367,2385, 2010. © 2010 Wiley-Liss, Inc. [source] Atrazine increases the sodium absorption in frog (Rana esculenta) skinENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2006Giuseppe Cassano Abstract The presence of atrazine in agricultural sites has been linked to the decline in amphibian populations. The efforts of the scientific community generally are directed toward investigating the long-term effect of atrazine on complex functions (reproduction or respiration), but in the present study, we investigated the short-term effect on the short-circuit current (ISC), a quantitative measure of the ion transport operated by frog (Rana esculenta) skin. Treatment with 5 ,M atrazine (1.08 mg/L) does not affect the transepithelial outfluxes of [14C]mannitol or [14C]urea; therefore, atrazine does not damage the barrier properties of frog skin. Atrazine causes a dose-dependent increase in the short-circuit current, with a minimum of 4.64 ± 0.76 ,A/cm2 (11.05% ± 1.22%) and a maximum of 12.7 ± 0.7 ,A/cm2 (35% ± 2.4%) measured at 10 nM and 5 ,M, respectively. An increase in ISC also is caused by 5 ,M ametryne, prometryn, simazine, terbuthylazine, or terbutryn (other atrazine derivatives). In particular, atrazine increases the transepithelial 22Na+ influx without affecting the outflux. Finally, stimulation of ISC by atrazine is suppressed by SQ 22536, H89, U73122, 2-aminoethoxydiphenyl borate, and W7 (blockers of adenylate cyclase, protein kinase A, phospholipase C, intracellular Ca2+ increase, and calmodulin, respectively), whereas indomethacin and calphostin C (inhibitors of cyclooxygenase and protein kinase C, respectively) have no effect. [source] Osteopontin and the skin: multiple emerging roles in cutaneous biology and pathologyEXPERIMENTAL DERMATOLOGY, Issue 9 2009Franziska Buback Abstract:, Osteopontin (OPN) is a glycoprotein expressed by various tissues and cells. The existence of variant forms of OPN as a secreted (sOPN) and intracellular (iOPN) protein and its modification through post-translational modification and proteolytic cleavage explain its broad range of functions. There is increasing knowledge which receptors OPN isoforms can bind to and which signaling pathways are activated to mediate different OPN functions. sOPN interacts with integrins and CD44, mediates cell adhesion, migration and tumor invasion, and has T helper 1 (Th1) cytokine functions and anti-apoptotic effects. iOPN has been described to regulate macrophage migration and interferon-, secretion in plasmacytoid dendritic cells. Both sOPN and iOPN, through complex functions for different dendritic cell subsets, participate in the regulation of Th cell lineages, among them Th17 cells. For skin disease, OPN from immune cells and tumor cells is of pathophysiological relevance. OPN is secreted in autoimmune diseases such as lupus erythematosus, and influences inflammation of immediate and delayed type allergies and granuloma formation. We describe that OPN is overexpressed in psoriasis and propose a model to study OPN function in psoriatic inflammation. Through cytokine functions, OPN supports immune responses against Mycobacteria and viruses such as herpes simplex virus. OPN is also implicated in skin tumor progression. Overexpression of OPN influences invasion and metastasis of melanoma and squamous cell carcinoma cells, and OPN expression in melanoma is a possible prognostic marker. As OPN protein preparations and anti-OPN antibodies may be available in the near future, in-depth knowledge of OPN functions may open new therapeutic approaches for skin diseases. [source] A strategy for correlative microscopy of large skin samples: towards a holistic view of axillary skin complexityEXPERIMENTAL DERMATOLOGY, Issue 1 2008Katrin Wilke Abstract:, Knowledge about the structural elements of skin and its appendices is an essential prerequisite for understanding their complex functions and interactions. The hence necessary morphological description across several orders of scale not only requires the investigation at the light microscopic level but also ultrastructural investigation, ideally on the identical sample. For a correlative and multimodal observation one unique preparation protocol is mandatory. As a compromise between sample sizes of >500 ,m in diameter on the one hand and optimal preservation of antigenicity and morphology on the other, we developed a new preparation protocol that allows (i) 3D reconstruction of the resin-embedded sample by confocal light microscopy prior to (ii) direct immunolocalization of target proteins within selected sample planes by light and fluorescence microscopy or transmission electron microscopy. Alternatively, (iii) serial cryosections of the frozen sample can be taken for characterizing the sample in toto. With this unique approach we were able to fully demonstrate the structural complexity of axillary skin samples, increasing the structural resolution from 3D reconstruction of the whole gland up to ultrastructural investigations at the subcellular level. We could demonstrate that axillary sweat glands are not separately distributed, as has been assumed to date; instead, they seem to be intricately twisted into one another. This promotes the concept of a complex axillary sweat gland organ instead of single sweat gland entities. [source] Modulating tone: the overture of S1P receptor immunotherapeuticsIMMUNOLOGICAL REVIEWS, Issue 1 2008Hugh Rosen Summary: Modulation of complex functions within the immune system has proven to be surprisingly sensitive to alterations in the lysophospholipid sphingosine 1-phosphate (S1P) receptor-ligand rheostat. This has become increasingly evident from both chemical and genetic manipulation of the S1P system, with pharmacological effects upon lymphoid cells, dendritic cell function, as well as vascular interfaces. The integrated immune system, perhaps as a result of its relatively recent evolutionary ontogeny, has selected for a number of critical control points regulated by five distinct high affinity G-protein-coupled receptor subtypes with a shared ligand, with receptors distributed on lymphocytes, dendritic cells, and endothelium. All of these cellular components of the axis are capable of modulating immune responses in vivo, with the impact on the immune response being very different from classical immunosuppressants, by virtue of selective spatial and temporal sparing of humoral and myeloid elements of host defense. Pharmacological subversion of the S1P rheostat is proving to be clinically efficacious in multiple sclerosis, and both the scope and limitations of therapeutic modulation of the S1P axis in immunotherapy are becoming clearer as understanding of the integrated chemical physiology of the S1P system emerges. [source] Decentralized nonlinear robust control of UAVs in close formationINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 11 2003Sahjendra N. Singh Abstract This paper treats the design of a decentralized nonlinear robust control system for formation flying of multiple unmanned aerial vehicles (UAVs). In close formation, it is assumed that vortex of any UAV affects the motion of all the UAVs behind it. The forces produced by these vortices are complex functions of relative position co-ordinates of the UAVs. In this paper, these forces are treated as unknown functions, which cannot be parameterized. Since the system is not invertible in the wind axes system, a simplified co-ordinate system obtained from the wind axes system for which the velocity roll (bank angle) is zero, is considered for the design of the control system. A nonlinear robust control system for the separation trajectory control of the wing aircraft in the simplified wind coordinate system is derived. Uncertain functions and unmeasured variables are estimated using a high-gain observer for the synthesis of the control system. Each wing UAV synthesizes its control law using its own state variables and the relative position of the preceding UAV with respect to the wing UAV. Thus the control system is decentralized since each UAV has to communicate (depending on sensors for position measurement) with at most one (preceding) UAV, and no data transmission from the remaining vehicles is required. Simulation results for two UAVs are presented which show precise separation trajectory control of each wing UAV in spite of the presence of unknown and unstructured vortex forces, while the lead aircraft maneuvers. Furthermore, these results confirm that when the wing aircraft is positioned properly in the vortex of the lead aircraft, it experiences reduction in its required flight power. Copyright © 2003 John Wiley & Sons, Ltd. [source] Regulation of phosphoinositide signaling by the inositol polyphosphate 5-phosphatasesIUBMB LIFE, Issue 8 2006Megan V. Astle Abstract Phosphoinositide signaling molecules control cellular growth, proliferation and differentiation, intracellular vesicle trafficking, and cytoskeletal rearrangement. The inositol polyphosphate 5-phosphatase family remove the D-5 position phosphate from PtdIns(3,4,5)P3, PtdIns(4,5)P2 and PtdIns(3,5)P2 forming PtdIns(3,4)P2, PtdIns(4)P and PtdIns(3)P respectively. This enzyme family, comprising ten mammalian members, exhibit seemingly non-redundant functions including the regulation of synaptic vesicle recycling, hematopoietic cell function and insulin signaling. Here we highlight recently established insights into the functions of two well characterized 5-phosphatases OCRL and SHIP2, which have been the subject of extensive functional studies, and the characterization of recently identified members, SKIP and PIPP, in order to highlight the diverse and complex functions of this enzyme family. iubmb Life, 58: 451 - 456, 2006 [source] Looking through the eyes of fungi: molecular genetics of photoreceptionMOLECULAR MICROBIOLOGY, Issue 1 2007Alfredo Herrera-Estrella Summary Filamentous fungi respond to a variety of environmental signals. One of them is light, providing critical information about orientation, or impending stress. Cells of filamentous fungi appear to sense blue light through a unique transcription factor that has a flavin chromophore and activates its targets in a light-dependent manner, the white collar (WC) complex. Fungal photophysiology, though, predicted a greater complexity of responses to the whole visible spectrum. The rapidly growing fungal genome database provides candidates to explain how fungi see not only blue, but also near-UV, green and red light. At the same time, there are surprises in the genomes, including photoreceptors for which there are no obvious photoresponses. Linking these genes and their functions will help understand how a list of only a few biological chromophores accounts for such a diversity of responses. At the same time, deeper mechanistic understanding of how the WC complex functions will lead to fundamental insights at the point where the environment impinges, in this case in the form of photons, on the transcriptional machinery of the cell. [source] Annotation: Deconstructing the attention deficit in fragile X syndrome: a developmental neuropsychological approachTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2004K.M. Cornish Background:, Fragile X syndrome is one of the world's leading hereditary causes of developmental delay in males. The past decade has witnessed an explosion of research that has begun to unravel the condition at its various levels: from the genetic and brain levels to the cognitive level, and then to the environmental and behavioural levels. Our aim in this review is to attempt to integrate some of the extensive body of knowledge to move the research a step closer to understanding how the dynamics of atypical development can influence the specific cognitive and behavioural end-states frequently observed in children and adolescents with fragile X syndrome. Methods:, We conducted a review of the current neuropsychological and neuropsychiatric approaches that have attempted to delineate the pattern of ,spared' and ,impaired' functions associated with the phenotype. Results:, The profile of findings suggests that fragile X syndrome should not be viewed merely as a catalogue of spared and impaired cognitive functions or modules. Instead, there appears to be a process of almost gradual modularisation whereby cognitive mechanisms become domain specific as a function of development itself (Karmiloff-Smith, 1992). The results of a decade of intense research point towards an early weakness in one or more components of executive control rather than single, static higher-level deficits (e.g., spatial cognition, speech processing). This weakness affects both the development of more complex functions and current performance. Conclusions:, The prevailing tendency to interpret developmental disorders in terms of fixed damage to distinct modular functions needs to be reconsidered. We offer this review as an example of an alternative approach, attempting to identify an initial deficit and its consequences for the course of development. Through better definition of the cognitive and behavioural phenotype, in combination with current progress in brain imaging techniques and molecular studies, the next decade should continue to hold exciting promise for fragile X syndrome and other neurodevelopmental disorders. [source] Preliminary X-ray crystallographic studies of yeast Get3ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2009Junbin Hu Tail-anchored (TA) proteins contain a single transmembrane domain (TMD) at the C-terminus. The post-translational insertion of TA proteins into the ER membrane requires the cooperation of the Golgi ER-trafficking (GET) complex, which contains Get1, Get2 and Get3. Get3 is a cytosolic ATPase which can recognize and bind the TMD of the TA proteins. Get1 and Get2 are ER transmembrane proteins which can recruit and form a complex with TA-bound Get3. The GET complex carries out an energy-dependent process that facilitates the insertion of the TA-protein TMD into the ER membrane. In order to investigate the mechanism by which the GET complex functions to promote protein insertion into the ER membrane, yeast Get3 has been crystallized. The crystals diffracted to 2.7,Ĺ resolution using a synchrotron X-ray source. The crystals belonged to space group P21212, with unit-cell parameters a = 220.26, b = 112.95, c = 48.27,Ĺ. There is one Get3 dimer in the asymmetric unit, which corresponds to a solvent content of approximately 65%. [source] | |||||||||||||||||||