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Hot Spots (hot + spot)
Kinds of Hot Spots Selected AbstractsPOLICING CRIME AND DISORDER HOT SPOTS: A RANDOMIZED CONTROLLED TRIAL,CRIMINOLOGY, Issue 3 2008ANTHONY A. BRAGA Dealing with physical and social disorder to prevent serious crime has become a central strategy for policing. This study evaluates the effects of policing disorder, within a problem-oriented policing framework, at crime and disorder hot spots in Lowell, Massachusetts. Thirty-four hot spots were matched into 17 pairs, and one member of each pair was allocated to treatment conditions in a randomized block field experiment. The officers engaged "shallow" problem solving and implemented a strategy that more closely resembled a general policing disorder strategy rather than carefully designed problem-oriented policing responses. Nevertheless, the impact evaluation revealed significant reductions in crime and disorder calls for service, and systematic observations of social and physical disorder at the treatment places relative to the control places uncovered no evidence of significant crime displacement. A mediation analysis of the isolated and exhaustive causal mechanisms that comprised the strategy revealed that the strongest crime-prevention gains were generated by situational prevention strategies rather than by misdemeanor arrests or social service strategies. [source] Personal Reflections on Saratoga Springs, New York: Hydrogeological and Horse Racing,Hot Spot' of the EastGROUND WATER, Issue 1 2004Donald I. Siegel No abstract is available for this article. [source] Hot Spots: Why Some Companies Buzz with Energy and Innovation , and Others Don't.R & D MANAGEMENT, Issue 1 2010By Lynda Gratton, Glow: How You Can Radiate Energy, Innovation, Success. No abstract is available for this article. [source] Direct Evidence of High Spatial Localization of Hot Spots in Surface-Enhanced Raman Scattering,ANGEWANDTE CHEMIE, Issue 52 2009Chang Chen Heiß oder kalt: Die hohe Lokalisierung in SERS-Hotspots lässt sich direkt anhand der selektiven Ablagerung von Raman-Analyten innerhalb und außerhalb von Regionen mit verstärktem Feld in einem Spalt zeigen (siehe Bild). Dies bestätigen Messungen der absoluten SERS-Intensitäten ebenso wie kinetische Studien zum lichtinduzierten Abbau an unterschiedlichen Stellen. [source] Detecting spatial hot spots in landscape ecologyECOGRAPHY, Issue 5 2008Trisalyn A. Nelson Hot spots are typically locations of abundant phenomena. In ecology, hot spots are often detected with a spatially global threshold, where a value for a given observation is compared with all values in a data set. When spatial relationships are important, spatially local definitions , those that compare the value for a given observation with locations in the vicinity, or the neighbourhood of the observation , provide a more explicit consideration of space. Here we outline spatial methods for hot spot detection: kernel estimation and local measures of spatial autocorrelation. To demonstrate these approaches, hot spots are detected in landscape level data on the magnitude of mountain pine beetle infestations. Using kernel estimators, we explore how selection of the neighbourhood size (,) and hot spot threshold impact hot spot detection. We found that as , increases, hot spots are larger and fewer; as the hot spot threshold increases, hot spots become larger and more plentiful and hot spots will reflect coarser scale spatial processes. The impact of spatial neighbourhood definitions on the delineation of hot spots identified with local measures of spatial autocorrelation was also investigated. In general, the larger the spatial neighbourhood used for analysis, the larger the area, or greater the number of areas, identified as hot spots. [source] Cover Picture: (Adv. Eng.ADVANCED ENGINEERING MATERIALS, Issue 8 2010Mater. The cover figure is selected from the article of G. Wilde et.al. It illustrates a strain map showing a detail of the in-plane rigid-body rotation ,xy. Hot spots refer to dislocation cores. The greenish colour represents the zero distortion. [source] An agonistic mAb directed to the TrkC receptor juxtamembrane region defines a trophic hot spot and interactions with p75 coreceptorsDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2010Veronique Guillemard Abstract The D5 domain of TrkC receptors is a docking site for Neurotrophin-3 (NT-3), but other domains may be relevant for function or harmonizing signals with p75NTR coreceptors. We report a monoclonal antibody (mAb) 2B7 targeting the juxtamembrane domain of TrkC. mAb 2B7 binds to murine and human TrkC receptors and is a functional agonist that affords activation of TrkC, AKT, and MAPK. These signals result in cell survival but not in cellular differentiation. Monomeric 2B7 Fabs also affords cell survival. Binding of 2B7 mAb and 2B7 Fabs to TrkC are blocked by NT-3 in a dose-dependent manner but not by pro-NT-3. Expression of p75NTR coreceptors on the cell surface block the binding and function of mAb 2B7, whereas NT-3 binding and function are enhanced. mAb 2B7 defines a previously unknown neurotrophin receptor functional hot spot; that exclusively generates survival signals; that can be activated by non-dimeric ligands; and potentially unmasks a site for p75-TrkC interactions. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2010. [source] Soils of a Mediterranean hot spot of biodiversity and endemism (Sardinia, Tyrrhenian Islands) are inhabited by pan-European, invasive species of Hypocrea/TrichodermaENVIRONMENTAL MICROBIOLOGY, Issue 1 2009Quirico Migheli Summary We have used a Mediterranean hot spot of biodiversity (the Island of Sardinia) to investigate the impact of abiotic factors on the distribution of species of the common soil fungus Trichoderma. To this end, we isolated 482 strains of Hypocrea/Trichoderma from 15 soils comprising undisturbed and disturbed environments (forest, shrub lands and undisturbed or extensively grazed grass steppes respectively). Isolates were identified at the species level by the oligonucleotide BarCode for Hypocrea/Trichoderma (TrichOKEY), sequence similarity analysis (Trichoblast) and phylogenetic inferences. The majority of the isolates were positively identified as pan-European and/or pan-global Hypocrea/Trichoderma species from sections Trichoderma and Pachybasium, comprising H. lixii/T. harzianum, T. gamsii, T. spirale, T. velutinum, T. hamatum, H. koningii/T. koningii, H. virens/T. virens, T. tomentosum, H. semiorbis, H. viridescens/T. viridescens, H. atroviridis/T. atroviride, T. asperellum, H. koningiopsis/T. koningiopsis and Trichoderma sp. Vd2. Only one isolate represented a new, undescribed species belonging to the Harzianum,Catoptron Clade. Internal transcribed spacer sequence analysis revealed only one potentially endemic internal transcribed spacer 1 allele of T. hamatum. All other species exhibited genotypes that were already found in Eurasia or in other continents. Only few cases of correlation of species occurrence with abiotic factors were recorded. The data suggest a strong reduction of native Hypocrea/Trichoderma diversity, which was replaced by extensive invasion of species from Eurasia, Africa and the Pacific Basin. [source] Relation between metal concentration in water and metal content of marine mussels (Mytilus galloprovincialis): Impact of physiology,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2008Stellio Casas Abstract The present study constitutes an in situ investigation of metal kinetics within soft tissue of mussels (Mytilus gallo-provincialis), which solves the problem of the decoupling of the effect of animal physiology and metal bioavailability in water. Field experiments were conducted to measure uptake and elimination kinetics for four metals (Hg, Pb, Cd, and Cu) in three Mediterranean sites with different contamination and nutritive levels. At each site, metal concentrations were monitored in soft tissues of mussels and in the surrounding waters. The experimental conditions were completely characterized: Lazaret Bay (located between Nice and Marseille, France) is a hot spot for Hg (6.3 ng/L) and Pb (163 ng/L) concentrations and is an oligotrophic, stable site; Bages Lagoon (located to the west of Montpellier, France) is particularly contaminated by Cd (1.5 ng/L) and Cu (1.5,g/L) and is a mesotrophic site where variability of trophic and physicochemical parameters is significant; and Port-Cros Island (located in the Hyeres National Park, France) is considered to be a reference site. Those kinetics permit us to decouple physiological, chemical, and environmental interactions. After normalizing mussel metal content for similar physiological conditions, application of the local weighted regression (LOWESS) statistical treatment shows a parallelism between the time trends of metal concentrations in the bivalve and metal concentrations in water. The results enabled us to obtain in situ kinetic parameters and realistic bioaccumulation factors. Their logarithmic values were 4.6 for Hg, 4.3 for Pb, 4.9 for Cd, and 3.9 for Cu. The importance of physiological processes such as spawning is discussed as a factor influencing the bioaccumulation factor. This information may be useful in refining monitoring tools for risk assessment and, more generally, in environmental management strategies. [source] A Simple Engineering Estimate of the Fatigue Notch Factor of Arbitrary Stress ConcentratorsADVANCED ENGINEERING MATERIALS, Issue 4 2010Hans-Peter Gaenser In fatigue life estimates, the fatigue stress endured at the hot spot is usually higher than what is predicted by the elastic stress concentration factor. Recently, Neuber's and Novozhilov's approaches of introducing an effective stress by averaging the actual stress field over a characteristic microstructural length have experienced a reappraisal. The present contribution aims at complementing these recent proposals by a mathematically simple engineering assessment of arbitrarily shaped notches, resulting in a closed-form expression for the fatigue notch factor. The limits of validity of the solution are discussed. [source] PHYLOGENETIC ANALYSIS OF ECOMORPHOLOGICAL DIVERGENCE, COMMUNITY STRUCTURE, AND DIVERSIFICATION RATES IN DUSKY SALAMANDERS (PLETHODONTIDAE: DESMOGNATHUS)EVOLUTION, Issue 9 2005Kenneth H. Kozak Abstract An important dimension of adaptive radiation is the degree to which diversification rates fluctuate or remain constant through time. Focusing on plethodontid salamanders of the genus Desmognathus, we present a novel synthetic analysis of phylogeographic history, rates of ecomorphological evolution and species accumulation, and community assembly in an adaptive radiation. Dusky salamanders are highly variable in life history, body size, and ecology, with many endemic lineages in the southern Appalachian Highlands of eastern North America. Our results show that lifehistory evolution had important consequences for the buildup of plethodontid-salamander species richness and phenotypic disparity in eastern North America, a global hot spot of salamander biodiversity. The origin of Desmognathus species with aquatic larvae was followed by a high rate of lineage accumulation, which then gradually decreased toward the present time. The peak period of lineage accumulation in the group coincides with evolutionary partitioning of lineages with aquatic larvae into seepage, stream-edge, and stream microhabitats. Phylogenetic simulations demonstrate a strong correlation between morphology and microhabitat ecology independent of phylogenetic effects and suggest that ecomorphological changes are concentrated early in the radiation of Desmognathus. Deep phylogeographic fragmentation within many codistributed ecomorph clades suggests long-term persistence of ecomorphological features and stability of endemic lineages and communities through multiple climatic cycles. Phylogenetic analyses of community structure show that ecomorphological divergence promotes the coexistence of lineages and that repeated, independent evolution of microhabitat-associated ecomorphs has a limited role in the evolutionary assembly of Desmognathus communities. Comparing and contrasting our results to other adaptive radiations having different biogeographic histories, our results suggest that rates of diversification during adaptive radiation are intimately linked to the degree to which community structure persists over evolutionary time. [source] Changes in fish assemblages in catchments in north-eastern Spain: biodiversity, conservation status and introduced speciesFRESHWATER BIOLOGY, Issue 8 2010ALBERTO MACEDA-VEIGA Summary 1. North-eastern Spain is a hot spot for the introduction of alien fish species, and its native fish fauna is one of the most endangered worldwide. We used an extensive data set from 2002 to 2003 and historical information from the area to characterize fish diversity and establish conservation priorities in river catchments. 2. Diversity indices were used to characterize fish diversity at the basin scale. An index of conservation status was applied for each species, which considers the occurrence, abundance and endemicity of each taxon. We used indirect ordination methods to test the relationship among basin features and to identify those variables most correlated with each other. To identify physical, biotic and environmental characteristics that seem to make a basin particularly susceptible to invasion, we performed a step-wise multiple regression to examine the relationship between the number of native, translocated and introduced fish species (including the original native species richness of each basin), and landscape variables. 3. Over a period of approximately 50 years, the mean range size of native fish species has decreased by 60%. The greatest decline occurred in Gasterosteus gymnurus, Anguilla anguilla and Salaria fluviatilis, for which species over 75% of the original distribution area has been lost. The species with the highest conservation index were Gasterosteus gymnurus and Salaria fluviatilis. 4. Basin area and the catchment type explained 70% of variation in native species richness, whereas the number of dams and basin area accounted for more than 80% of variation in the number of introduced species. 5. The original native species richness and the number of introduced species at basin scale were not related, and thus there was no evidence of "biotic resistance" to invasion. The restoration of natural hydrologic processes and the development of specific management tools to protect native species, such as the prioritization of areas for fish conservation and the eradication of local populations of exotic species, are required to restore native fish fauna in these catchments. [source] Gross SDHB deletions in patients with paraganglioma detected by multiplex PCR: A possible hot spot?GENES, CHROMOSOMES AND CANCER, Issue 3 2006Alberto Cascón Pheochromocytoma and paraganglioma are rare neuroendocrine tumors that arise in the adrenal medulla and the extra-adrenal paraganglia, respectively. Inheritance of these tumors is mainly a result of mutations affecting the VHL, RET, NF1, and SDH genes. Germ-line mutations of the SDH genes have been found to account for nearly 10% of apparently sporadic cases. Nevertheless, alterations other than point mutations have not yet been well characterized. In this study, we investigated the frequency of gross SDH deletions in 24 patients who tested negative for point mutations and had at least one of the recommended features for genetic testing. For this purpose, we used a technique that is easy to implement in the lab to specifically detect gross deletions affecting SDHB, SDHC, and SDHD. We identified 3 heterozygous SDHB deletions (3/24) in 3 independent cases with paraganglioma: 1 whole SDHB deletion and 2 deletions exclusively affecting exon 1. These latter mutations match the unique gross deletion previously reported, indicating this region could be a hot spot for gross SDHB deletions. It seems likely that these alterations can account for a considerable number of both familial and apparently sporadic paraganglioma cases. Although this is the first report describing the presence of gross deletions in patients with apparently sporadic paragangliomas, the extra-adrenal location of the tumor seems to constitute a determining factor for whether to include these patients in genetic testing for gross deletions in the SDHB gene. © 2005 Wiley-Liss, Inc. [source] A large Norwegian family with inherited malignant melanoma, multiple atypical nevi, and CDK4 mutationGENES, CHROMOSOMES AND CANCER, Issue 1 2005Anders Molven Mutations in two loci encoding cell-cycle-regulatory proteins have been shown to cause familial malignant melanoma. About 20% of melanoma-prone families bear a mutation in the CDKN2A locus, which encodes two unrelated proteins, p16INK4A and p14ARF. Mutations in the other locus, CDK4, are much rarer and have been linked to the disease in only three families worldwide. In the 1960s, a large Norwegian pedigree with multiple atypical nevi and malignant melanomas was identified. Subsequently, six generations and more than 100 family members were traced and 20 cases of melanoma verified. In this article, we report that CDK4 codon 24 is mutated from CGT to CAT (Arg24His) in this unusually large melanoma kindred. Intriguingly, one of the family members had ocular melanoma, but the CDK4 mutation could not be detected in archival tissue samples from this subject. Thus, the case of ocular melanoma in this family was sporadic, suggesting an etiology different from that of the skin tumors. The CDK4 mutation in the Norwegian family was identical to that in melanoma families in France, Australia, and England. Haplotype analysis using microsatellite markers flanking the CDK4 gene and single-nucleotide polymorphisms within the gene did not support the possibility that there was a common founder, but rather indicated at least two independent mutational events. All CDK4 melanoma families known to date have a substitution of amino acid 24. In addition to resulting from selection pressure, this observation may be explained by the CG dinucleotide of codon 24 representing a mutational hot spot in the CDK4 gene. © 2005 Wiley-Liss, Inc. [source] ARHGAP20 gene at 11q22.3,q23.1 oncogenomic recombination hot spotGENES, CHROMOSOMES AND CANCER, Issue 1 2005Masuko Katoh No abstract is available for this article. [source] Genomic context of paralogous recombination hotspots mediating recurrent NF1 region microdeletionGENES, CHROMOSOMES AND CANCER, Issue 1 2004Stephen H. Forbes Recombination between paralogs that flank the NF1 gene at 17q11.2 typically results in a 1.5-Mb microdeletion that includes NF1 and at least 13 other genes. We show that the principal sequences responsible are two 51-kb blocks with 97.5% sequence identity (NF1REP-P1-51 and NF1REP-M-51). These blocks belong to a complex group of paralogs with three components on 17q11.2 and another on 19p13.13. Breakpoint sequencing of deleted chromosomes from multiple patients revealed two paralogous recombination hot spots within the 51-kb blocks. Lack of sequence similarity between these sites failed to suggest or corroborate any putative cis -acting recombinogenic motifs. However, the NF1REPs showed relatively high alignment mismatch between recombining paralogs, and we note that the NF1REP hot spots were regions of good alignment bordered by relatively large alignment gaps. Statistical tests for gene conversion detected a single significant tract of perfect match between the NF1REPs that was 700 bp long and coincided with PRS2, the predominant recombination hot spot. Tracts of perfect match occurring by chance may contribute to breakpoint localization, but our result suggests that perfect tracts at recombination hot spots may be a result of gene conversion at sites at which preferential pairing occurs for other, as-yet-unknown reasons. © 2004 Wiley-Liss, Inc. [source] Numerical simulation of thermal runaway phenomena in silicon semiconductor devicesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2002Kazanori Shioda Abstract A mathematical model for heat production due to thermal excitation of conductive electrons and positive holes in a semiconductor pn junction is derived and discussed. The model is applied to simulate the thermal runaway phenomena in power electronics semiconductor devices. Our discussion focuses especially on the modeling of unexpected huge currents due to an excessive temperature increase. Calculated dynamics of temperature distributions of a silicon wafer while cooling performance decreases proved it is possible for a silicon wafer to be heated over its melting point in a few milliseconds. Our results indicate that if a local hot spot arises in a wafer, the thermal intrinsic excitation carries an increased diffusion current of minor carriers and a recombination current in the depletion layer of a pn junction. Also it appears to be important that cooling performance should be uniform on the wafer to avoid the growth of hot spots and thermal-runaway itself. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(6): 438,455, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10044 [source] A survey of H2 gene sequences, including new wild-derived genesINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 1 2007N. A. Mitchison Summary A comprehensive collection of mouse major histocompatibility complex (MHC) promoter and exon 2 sequences is here presented and analysed. It covers the three best known class II genes and one class I gene, and includes new wild mouse sequences from the ,w' back-cross strains and from the Jackson collection. All sequences are in GenBank, and the new exon sequences largely confirm previous typing by serology and immune function. As in human leucocyte antigen (HLA), the overall nucleotide diversity is higher in the class II genes, in keeping with their more diverse function. Diversity along the promoters is highest in the region of known transcription factor binding, most notably in and around the CRE and rCAAT sequences. This distribution parallels that of maximum single nucleotide polymorphism impact previously obtained with reporter constructs. Taking into account the low nucleotide diversity of the CIITA promoter, we conclude that MHC promoters are likely to have diversified through co-evolution with their exons, while themselves also directly subject to natural selection. The H2Ebp alleles form a distinct group, associated with their lack of the recombination hot spot located between exon 2 and exon 3. The collection is expected to prove useful in guiding functional and evolutionary studies. [source] Temperature Profiles in a Cylindrical Model Food During Pulsed Microwave HeatingJOURNAL OF FOOD SCIENCE, Issue 7 2001H.W. Yang ABSTRACT: Cylindrical 2%-agar gel samples were heated by pulsed and continuous microwave applications. The total microwave application time of 3 min was maintained for all experiments. Sample temperature was measured at various depths along the radial dimension to experimentally determine the internal temperature profile as a function of heating time. A local hot spot was observed at the center portion of the sample during the continuous microwave application. This hot spot was less significant during pulsed microwave applications, especially when longer intermittent power-off times were employed. An implicit finite-difference model was used to estimate temperature profiles within the sample during microwave heating. The estimated temperature profiles matched the experimental values well. [source] Oxygen isotope analysis of phosphate: improved precision using TC/EA CF-IRMS,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2009D. F. LaPorte Abstract Oxygen isotope values of biogenic apatite have long demonstrated considerable promise for paleothermometry potential because of the abundance of material in the fossil record and greater resistance of apatite to diagenesis compared to carbonate. Unfortunately, this promise has not been fully realized because of relatively poor precision of isotopic measurements, and exceedingly small size of some substrates for analysis. Building on previous work, we demonstrate that it is possible to improve precision of ,18OPO4 measurements using a ,reverse-plumbed' thermal conversion elemental analyzer (TC/EA) coupled to a continuous flow isotope ratio mass spectrometer (CF-IRMS) via a helium stream [Correction made here after initial online publication]. This modification to the flow of helium through the TC/EA, and careful location of the packing of glassy carbon fragments relative to the hot spot in the reactor, leads to narrower, more symmetrically distributed CO elution peaks with diminished tailing. In addition, we describe our apatite purification chemistry that uses nitric acid and cation exchange resin. Purification chemistry is optimized for processing small samples, minimizing isotopic fractionation of PO4,3 and permitting Ca, Sr and Nd to be eluted and purified further for the measurement of ,44Ca and 87Sr/86Sr in modern biogenic apatite and 143Nd/144Nd in fossil apatite. Our methodology yields an external precision of ± 0.15, (1,) for ,18OPO4. The uncertainty is related to the preparation of the Ag3PO4 salt, conversion to CO gas in a reversed-plumbed TC/EA, analysis of oxygen isotopes using a CF-IRMS, and uncertainty in constructing calibration lines that convert raw ,18O data to the VSMOW scale. Matrix matching of samples and standards for the purpose of calibration to the VSMOW scale was determined to be unnecessary. Our method requires only slightly modified equipment that is widely available. This fact, and the demonstrated improvement in precision, should help to make apatite paleothermometry far more accessible to paleoclimate researchers. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modelling species diversity through species level hierarchical modellingJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2005Alan E. Gelfand Summary., Understanding spatial patterns of species diversity and the distributions of individ-ual species is a consuming problem in biogeography and conservation. The Cape floristic region of South Africa is a global hot spot of diversity and endemism, and the Protea atlas project, with about 60 000 site records across the region, provides an extraordinarily rich data set to model patterns of biodiversity. Model development is focused spatially at the scale of 1, grid cells (about 37 000 cells total for the region). We report on results for 23 species of a flowering plant family known as Proteaceae (of about 330 in the Cape floristic region) for a defined subregion. Using a Bayesian framework, we developed a two-stage, spatially explicit, hierarchical logistic regression. Stage 1 models the potential probability of presence or absence for each species at each cell, given species attributes, grid cell (site level) environmental data with species level coefficients, and a spatial random effect. The second level of the hierarchy models the probability of observing each species in each cell given that it is present. Because the atlas data are not evenly distributed across the landscape, grid cells contain variable numbers of sampling localities. Thus this model takes the sampling intensity at each site into account by assuming that the total number of times that a particular species was observed within a site follows a binomial distribution. After assigning prior distributions to all quantities in the model, samples from the posterior distribution were obtained via Markov chain Monte Carlo methods. Results are mapped as the model-estimated probability of presence for each species across the domain. This provides an alternative to customary empirical ,range-of-occupancy' displays. Summing yields the predicted richness of species over the region. Summaries of the posterior for each environmental coefficient show which variables are most important in explaining the presence of species. Our initial results describe biogeographical patterns over the modelled region remarkably well. In particular, species local population size and mode of dispersal contribute significantly to predicting patterns, along with annual precipitation, the coefficient of variation in rainfall and elevation. [source] Dopamine agonists restore cortical plasticity in patients with idiopathic restless legs syndrome,MOVEMENT DISORDERS, Issue 5 2009Vincenzo Rizzo MD Abstract In the present work, we aimed at assessing whether patients with idiopathic restless legs syndrome (RLS) showed alterations of sensory-motor plasticity, an indirect probe for motor learning, within the motor cortex (M1). Previous findings suggest that learning in human M1 occurs through LTP-like mechanisms. To test our hypothesis, we employed the paired associative stimulation (PAS) protocol by transcranial magnetic stimulation (TMS), which is able to induce LTP-like effects in the motor cortex of normal subjects. Twelve patients with idiopathic RLS and 10 age- and sex-matched control subjects were recruited. PAS protocol consisted of 0.05 Hz electrical median nerve stimulation (90 stimuli), paired with 0.05 Hz TMS (90 stimuli) over the hot spot for stimulating the abductor pollicis brevis (APB) muscle given 25 milliseconds after the onset of the electrical stimulus. Corticospinal excitability recorded in APB muscle, as indexed by MEP obtained after single stimulus, was tested before and up to 30 minutes after PAS protocol. Eight of 12 patients were studied before and after 4 weeks of dopaminergic treatment. PAS protocol increased significantly corticospinal excitability as long as 30 minutes in healthy subjects. On the contrary, PAS protocol did not change the amplitude of MEPs in patients with idiopathic RLS without treatment. PAS associative plasticity was restored after 4 weeks of dopaminergic treatment. Our data demonstrated that associative sensory-motor plasticity, an indirect probe for motor learning, is impaired in idiopathic RLS patients but may be reverted to normal after dopaminergic treatment. © 2008 Movement Disorder Society [source] Characterization of the binding surface of the translocated intimin receptor, an essential protein for EPEC and EHEC cell adhesionPROTEIN SCIENCE, Issue 12 2007Nathan T. Ross Abstract The translocated intimin receptor (TIR) of enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) is required for EPEC and EHEC infections, which cause widespread illness across the globe. TIR is translocated via a type-III secretion system into the intestinal epithelial cell membrane, where it serves as an anchor for E. coli attachment via its binding partner intimin. While many aspects of EPEC and EHEC infection are now well understood, the importance of the intermolecular contacts made between intimin and TIR have not been thoroughly investigated. Herein we report site-directed mutagenesis studies on the intimin-binding domain of EPEC TIR, and how these mutations affect TIR-intimin association, as analyzed by isothermal titration calorimetry and circular dichroism. These results show how two factors govern TIR's binding to intimin: A three-residue TIR hot spot is identified that largely mediates the interaction, and mutants that alter the ,-hairpin structure of TIR severely diminish binding affinity. In addition, peptides incorporating key TIR residues identified by mutagenesis are incapable of binding intimin. These results indicate that hot spot residues and structural orientation/preorganization are required for EPEC, and likely EHEC, TIR-intimin binding. [source] Analysis of ligand binding to a ribose biosensor using site-directed mutagenesis and fluorescence spectroscopyPROTEIN SCIENCE, Issue 3 2007Natalie C. Vercillo Abstract Computational design of proteins with altered ligand specificity is an emerging method for the creation of new biosensing systems. In this work, we investigated the outcome of site-directed mutagenesis on the Escherichia coli ribose binding protein (RBP), which is frequently used as a design scaffold for computational searches. A ribose biosensor was first constructed whereby an environmentally sensitive fluorescent probe was covalently attached to RBP at position S265C. This protein conjugate displayed a 54% decrease in emission intensity upon the addition of saturating ribose concentrations and exhibited an apparent dissociation constant (Kd) of 3.4 ,M. Site-directed mutants within the RBP binding pocket were created and examined for ribose binding ability and overall structural stability. Because as many as 12 mutations are needed to alter ligand specificity in RBP, we measured the effect of single and multiple alanine mutations on stability and signal transduction potential of the ribose biosensor. Single alanine mutations had significant impact on both stability and signaling. Mutations of N190A and F214A each produced melting temperatures >8°C below those observed for the wild-type protein. Residue Q235, located in the hinge region of RBP, appeared to be a hot spot for global protein stability as well. Additional single alanine mutations demonstrated as much as 200-fold increase in apparent Kd but retained overall protein stability. The data collected from this study may be incorporated into design algorithms to help create more stable biosensors and optimize signal transduction properties for a variety of important analytes. [source] Best Available Treatment Technologies Applied to Groundwater Circulation WellsREMEDIATION, Issue 3 2002Andrew Curtis Elmore Groundwater circulation wells (GCWs) are a quasi-in-situ method for remediating groundwater in areas where remediation techniques that limit the water available for municipal, domestic, industrial, or agricultural purposes are inappropriate. The inherently resource-conservative nature of groundwater circulation wells is also philosophically appealing in today's culture, which is supportive of green technologies. Groundwater circulation wells involve the circulation of groundwater through a dual-screen well, with treatment occurring between the screens. The wells are specifically designed so that one well screen draws in groundwater and the second returns the groundwater after it has been treated within the well. Historically, the treatment has been performed with specialized equipment proprietary to GCW vendors. Two full-scale pilot systems at a formerly used Defense Superfund site in Nebraska used best available technologies for treatment components. A multiple-tray, low-profile air stripper typically used for pump-and-treat remediation systems was successfully adapted for the GCW pilot system located in a trichloroethylene (TCE) hot spot. An ultraviolet water disinfection system was successfully adapted for the GCW pilot system located in a hot spot contaminated with the explosive compound hexhydro-1,3,5-trinitro-1,3,5-triazine (RDX). The pilot systems showed that GCW technology is competitive with a previously considered pump-and-treat alternative for focused extraction, and the regulatory community was supportive of additional GCW applications. A remedial design for the site includes 12 more GCW systems to complete focused remediation requirements. © 2002 Wiley Periodicals, Inc. [source] Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Susanna Piovano Abstract 1.A known fishing hot spot for loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea is in the waters of the Strait of Sicily where interactions with fish hooks and branchlines are believed to be a major cause of mortality for sea turtles. 2.Hooks with different shapes but a similar gape width (circle hook size 16/0 vs J hook size 2) were tested in order to determine the potential effectiveness of the hook design to both reduce sea turtle capture as well as to maintain acceptable levels of target species capture rates in a shallow-set longline swordfish fishery in the Mediterranean. 3.Seven experimental fishing trips, 30,000 hooks total, were conducted on a single commercial fishing vessel (18,m in length) in the Strait of Sicily during the months of July through October over a period of three years from 2005 to 2007. Circle and J hooks were alternated along the mainline. 4.A total of 26 sea turtles were hooked, all immature-size Caretta caretta. Turtles were caught at a statistically greater frequency on J hooks than on circle hooks. The capture rate, weight, and upper jaw fork length of the target species were not significantly different between the two types of hooks employed. 5.Five sea turtles swallowed the hook and in all such cases these were J type. Circle hooks tended to be located externally and were more easily detected by fishermen, and could be removed with the correct dehooking action before returning the turtle to the sea. 6.These findings suggest that 16/0 circle hooks can effectively reduce the incidental capture of immature loggerhead sea turtles in a Mediterranean swordfish longline fishery without affecting the catch size of the target species. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fate of baby radio galaxies: Dead or alive?ASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009N. Kawakatu Abstract In order to reveal the long-term evolution of relativistic jets in active galactic nuclei (AGNs), we examine the dynamical evolution of variously-sized radio galaxies [i.e., compact symmetric objects (CSOs), medium-size symmetric objects (MSOs), Fanaroff-Riley type II radio galaxies (FRIIs)]. By comparing the observed relation between the hot spot size and the linear size of radio source with a coevolution model of hot spot and cocoon, we find that the advance speed of hot spots and lobes inevitably show the deceleration phase (CSO-MSO phase) and the acceleration phase (MSO-FRII phase). The deceleration is caused by the growth of the cross-sectional area of the cocoon head. Moreover, by comparing the hot spot speed with the sound speed of the ambient medium, we predict that only CSOs whose initial advance speed is higher than 0.3,0.5 c can evolve into FRIIs (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Inactivation of the CDKN2A and the p53 tumour suppressor genes in external genital carcinomas and their precursorsBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2007N. Soufir Summary Background, p53 has been extensively studied in external genital carcinoma (EGC), and is frequently inactivated, but little is known about the role of the CDKN2A tumour suppressor gene in the oncogenesis of EGC. Objectives, To investigate the role of CDKN2A and p53 in the pathogenesis of EGCs and their precursor lesions vulval intraepithelial neoplasia (VIN3), penile intraepithelial neoplasia and lichen sclerosus (LS). Methods, By means of CDKN2A and p53 mutation screening (single-strand conformational polymorphism analysis and sequencing), methylation analysis of alternative CDKN2A promoters (methylation-specific polymerase chain reaction) and p53 immununochemistry, we analysed eight invasive EGCs (five from vulva and three from penis) and 25 precancerous lesions (two undifferentiated VIN3 and 23 vulval/penile lesions of LS) from 33 patients. Results, p53 mutations (mainly transversions) and CDKN2A mutations (including one hot spot) were present in 75% and 50% of invasive tumours, respectively, but were absent in all precancerous lesions. Remarkably, all CDKN2A -mutated tumours also harboured a p53 mutation. CDKN2A or p53 mutations were observed more frequently in LS-derived EGCs than in human papillomavirus-derived EGCs (P = 0·053). A positive anti-p53 staining, but without p53 mutations, was also detected in 30% of LS lesions, suggesting a p53 stabilization in response to inflammation and carcinogenic insult. Methylation of p16INK4a and p14ARF promoters was not a frequent mechanism of CDKN2A inactivation. Conclusions, Our study shows a high prevalence of co-inactivating mutations of p53 and/or CDKN2A genes in EGC, that seem to occur preferentially in LS-derived tumours and late in oncogenesis. [source] Protection against Malignant Progression of Spontaneously Developing Liver Tumors in Transgenic Mice Expressing O6 -Methylguanine-DNA MethyltransferaseCANCER SCIENCE, Issue 11 2000Xiusheng Qin To study the effect of O6 -methylguanine-DNA methyltransferase (MGMT) on carcinogenesis, we have previously generated MGMT transgenic mice overexpressing the bacterial MGMT gene, ada, and demonstrated that high MGMT levels in the liver suppress induction of liver tumors after treatment with an alkylating hepatocarcinogen. To examine the effects of life-long elevation of MGMT activity on mouse spontaneous liver tumor development, ada-transgenic and control nontransgenic mice were compared. We also examined mutations at codon 61 of the H-ras oncogene, reported as a hot spot in mouse liver tumors, using a direct DNA sequencing method. The results revealed no significant difference in tumor incidence or mutation spectrum, but interestingly, ada-transgenic mice were found to have fewer malignant tumors and survived longer, indicating a possible protective role of MGMT against malignant conversion. [source] Development of an Industrial Multi-Injection Microreactor for Fast and Exothermic Reactions , Part IICHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2008D. M. Roberge Abstract A Grignard reaction performed in a microreactor is presented. The reaction is of type A (highly exothermic and very rapid) and has a low yield which is attributed to a hot spot formed in the mixing zone of the reactor. The reaction yield could be significantly increased by applying the multi-injection principle, leading to better thermal control in the microreactor. Nevertheless, the microreactor plays a major role in reducing the magnitude of the hot spot. Knowing this, it was possible to design and construct an industrial microreactor with significant advantages such as modularity, high flow rate operation, and low investment expenditure (pumps and flow controller minimization). [source] | |||||||||||||||||||||||||||||||||||||||||||||||||