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Multiple Sites (multiple + site)
Selected AbstractsChemInform Abstract: Optical Properties of Multiple Sites of Eu3+ in SrY2O4 Single-Crystal Fibers.CHEMINFORM, Issue 11 2002Wuliang Xu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Multiple sites of L-histidine decarboxylase expression in mouse suggest novel developmental functions for histamineDEVELOPMENTAL DYNAMICS, Issue 1 2001Kaj Karlstedt Abstract Histamine mediates many types of physiologic signals in multicellular organisms. To clarify the developmental role of histamine, we have examined the developmental expression of L-histidine decarboxylase (HDC) mRNA and the production of histamine during mouse development. The predominant expression of HDC in mouse development was seen in mast cells. The HDC expression was evident from embryonal day 13 (Ed13) until birth, and the mast cells were seen in most peripheral tissues. Several novel sites with a prominent HDC mRNA expression were revealed. In the brain, the choroid plexus showed HDC expression at Ed14 and the raphe neurons at Ed15. Close to the parturition, at Ed19, the neurons in the tuberomammillary (TM) area and the ventricular neuroepithelia also displayed a clear HDC mRNA expression and histamine immunoreactivity (HA-ir). From Ed14 until birth, the olfactory and nasopharyngeal epithelia showed an intense HDC mRNA expression and HA-ir. In the olfactory epithelia, the olfactory receptor neurons (ORN) were shown to have very prominent histamine immunoreactivity. The bipolar nerve cells in the epithelium extended both to the epithelial surface and into the subepithelial layers to be collected into thick nerve bundles extending caudally toward the olfactory bulbs. Also, in the nasopharynx, an extensive subepithelial network of histamine-immunoreactive nerve fibers were seen. Furthermore, in the peripheral tissues, the degenerating mesonephros (Ed14) and the convoluted tubules in the developing kidneys (Ed15) showed HDC expression, as did the prostate gland (Ed15). In adult mouse brain, the HDC expression resembled the neuronal pattern observed in rat brain. The expression was restricted to the TM area in the ventral hypothalamus, with the main expression in the five TM subgroups called E1,E5. A distinct mouse HDC mRNA expression was also seen in the ependymal wall of the third ventricle, which has not been reported in the rat. The tissue- and cell-specific expression patterns of HDC and histamine presented in this work indicate that histamine could have cell guidance or regulatory roles in development. © 2001 Wiley-Liss, Inc. [source] Late Quaternary deglacial history of the Mérida Andes, Venezuela,JOURNAL OF QUATERNARY SCIENCE, Issue 7-8 2005Nathan D. Stansell Abstract Radiocarbon-dated sediment cores from seven lakes and two bogs spanning the Cordillera de Mérida in the Venezuelan Andes were used to identify and date the regional history of late Pleistocene and Holocene glacial activity. Coring sites were selected at different elevations across a pronounced rain shadow from southeast (wet) to northwest (dry). Sediment lithostratigraphy and magnetic susceptibility, in conjunction with AMS radiocarbon dates on macrofossils and charcoal, were used to constrain deglaciation. The local expression of the Last Glacial Maximum occurred between 22,750 and 19,960,cal.,yr,BP. On the wetter southeastern side of the Cordillera de Mérida, glaciers had significantly retreated by 15,700,cal.,yr,BP, followed by several minor glacial advances and retreats between 14,850 and 13,830,cal.,yr,BP. At least one major glacial readvance occurred between 13,830 and 10,000,cal.,yr,BP in the wetter southeastern sector of the region. The drier northwest side of the Cordillera de Mérida records initial glacial retreat by 14,240,cal.,yr,BP. Multiple sites on both sides of the Mérida Andes record a further phase of extensive deglaciation approximately 10,000,cal.,yr,BP. However, the north-northwest facing Mucubají catchment remained partially glaciated until ca. 6000,cal.,yr,BP. Deglacial ages from the Venezuelan Andes are consistently younger than those reported from the Southern Hemisphere Andes, suggesting an inter-hemispheric deglacial lag in the northern tropics of the order of two thousand years. Copyright © 2005 John Wiley & Sons, Ltd. [source] Laryngeal Preservation With Supracricoid Partial Laryngectomy Results in Improved Quality of Life When Compared With Total Laryngectomy,THE LARYNGOSCOPE, Issue 2 2001Gregory S. Weinstein MD Abstract Objectives/Hypotheses Study 1: To assess the oncologic outcome following supracricoid partial laryngectomy (SCPL). Study 2: To compare the quality of life (QOL) following SCPL to total laryngectomy (TL) with tracheoesophageal puncture (TEP). Study 3: To analyze whole organ TL sections to determine the percentage of lesions amenable to SCPL. Study Design Study 1: A retrospective review of patients who underwent SCPL. Study 2: A non-randomized, prospective study using QOL instruments to compare patients who underwent either SCPL or TL. Study 3: A retrospective histopathologic study of TL specimens assessed for the possibility of performing an SCPL. Methods Study 1: Twenty-five patients with carcinoma of the larynx underwent SCPL between June 1992 and June 1999. Various rates of oncologic outcome were calculated. Study 2: Thirty-one patients participated in the QOL assessment. This included the SF-36 general health status measure, the University of Michigan Head and Neck Quality of Life (HNQOL) instrument, and the University of Michigan Voice-Related Quality of Life (VRQOL) instrument. Study 3: Ninety surgical specimens were obtained and studied from the total laryngectomy cases in the Tucker Collection. Multiple sites were evaluated for the presence of carcinoma. A computer program was written to classify whether the patient was amenable to SCPL. Results Study 1: The overall local control rate was 96% (24/25). The local control rate following SCPL with cricohyoidoepiglottopexy (CHEP) was 95% (20/21). The local control rate following SCPL with cricohyoidopexy (CHP) was 100% (4/4). Study 2: The SCPL had significantly higher domain scores than TL and TEP in the following categories for the SF-36: physical function, physical limitations, general health, vitality, social functioning, emotional limitations, and physical health summary. The significantly higher domains for the SCPL when compared with the TL and TEP for the HNQOL were eating and pain. Finally, when voice-related QOL was assessed with the V-RQOL, the domains of physical functioning and the total score were significantly better with SCPL when compared with TL and TEP. Study 3: Forty of 90 (44%) laryngeal whole organ specimens were determined to be resectable by SCPL. In 16 (18%) specimens, the patients could have undergone SCPL with CHEP and in 24 (27%) specimens the patients could have undergone SCPL with CHP. Among the 40 (44%) specimens determined to be able to have undergone SCPL, 19 were glottic (1 T1, 15 T2, 3 T3) and 21 were supraglottic (9 T2, 12 T3). Conclusions 1) A review of the literature and an analysis of the data in this study indicate that excellent local control may be expected following SCPL. 2) The QOL following SCPL, as measured by three validated QOL instruments, is superior to TL with TEP. 3) A histologic assessment of whole organ sections of TL specimens indicates that many patients who have been subjected to TL may have been candidates for SCPL. 4) If the indications and contraindications are rigorously adhered to, SCPLs are reasonable alternatives to TL in selected cases. [source] Neurulation in the human embryo revisitedCONGENITAL ANOMALIES, Issue 2 2000Tomoko Nakatsu ABSTRACT It used to be widely accepted that neural tube closure in the human initiates at the level of the future neck and proceeds both cranially and caudally like zip fastener closing. This continuous closure model was recently challenged, and observation of human embryos at the neurulation stage revealed that the closure of the human neural tube initiates at multiple sites. Multi-site closure of the neural tube has been observed in many other animal species, but the initiation sites and the process of neural tube closure are variable among species. Therefore we should be careful when extrapolating the data of normal and abnormal neurulation in laboratory animals to the human. Recent studies in mouse genetics and developmental biology have shown that neural tube defects are quite heterogeneous both etiologically and pathogenetically. Gene mutations responsible for human neural tube defects are largely unknown, but molecular studies of human cases of neural tube defects and their comparison with the mouse genome data should provide a molecular basis for human neural tube defects. [source] Ecological Traits Predicting Amphibian Population Declines in Central AmericaCONSERVATION BIOLOGY, Issue 4 2003Karen R. Lips Populations of some species are extirpated, others have declined but survive, some have not obviously declined, and some are increasing. If amphibian populations at multiple sites were affected by the same factors, then surviving species should share traits that promote persistence, whereas declining species should share traits that promote susceptibility. Identifying these traits can help diagnose potential causes and thus help to direct conservation actions. Using logistic regression, we quantified the vulnerability of amphibian populations in four areas in Central America. We analyzed a species-specific database of taxonomic identity, geographic and elevational range, elevational distribution, adult and larval habitat, activity period, and maximum adult body size. We found that ( 1 ) all four sites exhibited the same pattern of decline ( there were no interactions between site and other variables ); ( 2 ) declining populations shared aquatic habitats, restricted elevational ranges, and large body sizes; and ( 3 ) there was an interaction between body size and elevational range. The most significant variable in the model was lifetime aquatic index, a factor unrelated to demographic vulnerability and one that therefore might indicate the potential causative agent( s ). Our results provide a predictive model with which to assess potential causes of population declines in other areas, and we generated a list of 52 species predicted to decline at a currently unaffected site in central Panama. Resumen: Las poblaciones de anfibios están declinando en todos los continentes donde ocurren, pero no todas las especies han sido afectadas por igual. Algunas especies han sido extirpadas, otras han declinado pero sobreviven, algunas no han declinado notablemente y otras están aumentando. Si las poblaciones de anfibios en varios sitios fueran afectadas por los mismos factores, las especies sobrevivientes deberían compartir características que promuevan la persistencia mientras que las especies en declinación deberían compartir características que promuevan la susceptibilidad. La identificación de estas características puede ayudar a diagnosticar las causas potenciales y así ayudar a dirigir medidas de conservación. Utilizando regresión logística, cuantificamos la vulnerabilidad de las poblaciones de anfibios en cuatro áreas de Centro América. Analizamos una base de datos de identidad taxonómica de especies, rango geográfico y altitudinal, distribución altitudinal, hábitat de larvas y adultos, período de actividad y máxima talla corporal de adultos. Encontramos que ( 1 ) los cuatro sitios presentaron el mismo patrón de declinación ( no hubo interacciones entre el sitio y otras variables ), ( 2 ) las poblaciones en declinación compartieron hábitats acuáticos, rangos altitudinales restringidos y tamaño corporal grande y ( 3 ) hubo interacción entre el tamaño corporal y el rango altitudinal. La variable más significativa del modelo fue el índice de vida acuática, un factor no relacionado con la vulnerabilidad demográfica y que, por lo tanto, podría indicar el agente causal potencial. Nuestros resultados proporcionan un modelo predictivo para evaluar las causas potenciales de declinación poblacional en otras áreas, y generamos una lista de 52 especies de declinación prevista en un sitio actualmente no afectado del centro de Panamá. [source] Ror2 knockout mouse as a model for the developmental pathology of autosomal recessive Robinow syndromeDEVELOPMENTAL DYNAMICS, Issue 2 2004Georg C. Schwabe Abstract Robinow syndrome (RS) is a human dwarfism syndrome characterized by mesomelic limb shortening, vertebral and craniofacial malformations and small external genitals. We have analyzed Ror2 -/- mice as a model for the developmental pathology of RS. Our results demonstrate that vertebral malformations in Ror2 -/- mice are due to reductions in the presomitic mesoderm and defects in somitogenesis. Mesomelic limb shortening in Ror2 -/- mice is a consequence of perturbed chondrocyte differentiation. Moreover, we show that the craniofacial phenotype is caused by a midline outgrowth defect. Ror2 expression in the genital tubercle and its reduced size in Ror2 -/- mice makes it likely that Ror2 is involved in genital development. In conclusion, our findings suggest that Ror2 is essential at multiple sites during development. The Ror2 -/- mouse provides a suitable model that may help to explain many of the underlying developmental malformations in individuals with Robinow syndrome. Developmental Dynamics 229:400,410, 2004, © 2004 Wiley-Liss, Inc. [source] Widespread resistance of Mediterranean island ecosystems to the establishment of three alien speciesDIVERSITY AND DISTRIBUTIONS, Issue 5 2008Montserrat Vilà ABSTRACT Although some invasive plants are cosmopolitan, not all ecosystems are invaded to the same degree. Yet there is little experimental work on how ecosystem resistance to invasion at the establishment phase differs among ecosystems. We conducted two field sowing experiments in two consecutive years to examine establishment of the deciduous tree Ailanthus altissima, the succulent subshrub Carpobrotus spp. and the annual geophyte Oxalis pes-caprae in coastal dunes, shrublands and oldfields in more than 200 sites across six Mediterranean Basin islands differing in climatic conditions and local species richness. Establishment success (i.e. percentage of plots with at least one seedling) and rates (i.e. seedling to sown seed ratio) were low, especially for Ailanthus even when accounting for differences in seed viability. Oxalis was capable of producing a new cohort of seedlings the year following planting. By contrast, all Ailanthus seedlings and half the Carpobrotus seedlings died following the first summer. Differences in establishment success and rates among ecosystems were species-, island- and year-dependent. Differences in precipitation and mean temperature were associated with differences in establishment rates across sites. Establishment rates tended to be positively correlated with cumulative precipitation and negatively with mean Ta. Unexpectedly, native species richness was not a good predictor of seedling establishment, except for higher Oxalis establishment success in species rich habitats. By conducting field sowing tests at multiple sites across a region we found that except for Oxalis, Mediterranean island ecosystems are quite resistant to invader establishment. These results suggest that differences in the degree of invasion between ecosystems and islands might be more dependent upon the influence of invasion event factors (e.g. propagule pressure) or factors acting at a later life-history stages rather than differences in the resistance imposed by ecosystems to invader recruitment. Moreover, our results support the notion that in Mediterranean ecosystems invasions are highly idiosyncratic events and strongly dependent on water availability conditions. [source] Correlation model for spatially distributed ground-motion intensitiesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 15 2009Nirmal Jayaram Abstract Risk assessment of spatially distributed building portfolios or infrastructure systems requires quantification of the joint occurrence of ground-motion intensities at several sites, during the same earthquake. The ground-motion models that are used for site-specific hazard analysis do not provide information on the spatial correlation between ground-motion intensities, which is required for the joint prediction of intensities at multiple sites. Moreover, researchers who have previously computed these correlations using observed ground-motion recordings differ in their estimates of spatial correlation. In this paper, ground motions observed during seven past earthquakes are used to estimate correlations between spatially distributed spectral accelerations at various spectral periods. Geostatistical tools are used to quantify and express the observed correlations in a standard format. The estimated correlation model is also compared with previously published results, and apparent discrepancies among the previous results are explained. The analysis shows that the spatial correlation reduces with increasing separation between the sites of interest. The rate of decay of correlation typically decreases with increasing spectral acceleration period. At periods longer than 2,s, the correlations were similar for all the earthquake ground motions considered. At shorter periods, however, the correlations were found to be related to the local-site conditions (as indicated by site Vs30 values) at the ground-motion recording stations. The research work also investigates the assumption of isotropy used in developing the spatial correlation models. It is seen using the Northridge and Chi-Chi earthquake time histories that the isotropy assumption is reasonable at both long and short periods. Based on the factors identified as influencing the spatial correlation, a model is developed that can be used to select appropriate correlation estimates for use in practical risk assessment problems. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of plant invasions on the species richness of abandoned agricultural landECOGRAPHY, Issue 6 2001Scott J. Meiners While exotic plant invasions are thought to lead to declines in native species, the long-term impacts of such invasions on community structure are poorly known. Furthermore, it is unknown how exotic plant invasions compare to invasions by native species. We present data from 40 yr of continuous vegetation sampling of 10 fields released from agriculture to examine the effects of invasions on species richness. The effects of both exotic and native species invasions on species richness were largely driven by variations among fields with most species not significantly affecting species richness. However, invasion and dominance by the exotics Agropyron repens, Lonicera japonica. Rosa multiflora. Trifolium pratense and the native Solidago canadensis were associated with declines in richness. Invasions by exotic and native species during old field succession have similar effects on species richness with dominance by species of either group being associated with loss of species richness. Exotic species invasions tended to have stronger effects on richness than native invasions. No evidence was found of residual effects of invasions because the impact of the invasion disappeared with the decline of the invading population. When pooled across species, heavy invasion by exotic species resulted in greater loss o species richness than invasion by native species. Studies of invasion that utilize multiple sites must account for variability among sites. In our study, had we no included field as a factor we would have incorrectly concluded that invasion consistently resulted in changes in species richness. [source] A new optimal foraging model predicts habitat use by drift-feeding stream minnowsECOLOGY OF FRESHWATER FISH, Issue 1 2002G. D. Grossman Abstract , There is substantial need for models that accurately predict habitat selection by fishes for purposes ranging from the elaboration of ecological theory to the preservation of biodiversity. We have developed a new and highly tractable optimal foraging model for drift-feeding fishes that is based on the profitability of occupying varying focal-point velocities in a stream. The basic model can be written as: Ix = (Ex * Px) = {(D * A * V) * [1/(1 + e(b + cV))]} , Sx, where: (1) Ix is the net energy intake at velocity x; (2) E is prey encounter rate; (3) P is prey capture success rate which can be modelled as 1/(1 + e(b + cV)) where b and c are fitting constants from the prey capture success curve; (4) D is the energy content of prey (J/m3) in the drift; (5) A is the visual reactive area of the fish; (6) V is velocity (cm/s); and (7) S is the cost of maintaining position (J/s). Given that D, A and S can be considered constant over the range of velocities occupied by these fishes, the model reduces to e(b + cV) = 1/(cV , 1) which we solved iteratively to yield an optimal focal-point velocity for species in each sample. We tested the model by comparing its predictions to the mean focal-point velocities (i.e. microhabitats) occupied by four species of drift-feeding minnows in two sites in a stream in North Carolina, USA. The model successfully predicted focal-point velocities occupied by these species (11 out of 14 cases) in three seasonal samples collected over 2 years at two sites. The unsuccessful predictions still were within 2 cm/s of the 95% confidence intervals of mean velocities occupied by fishes, whereas the overall mean deviation between optimal velocities and mean fish velocities was small (range = 0.9 and 3.3 cm/s for the warpaint shiner and the Tennessee shiner, respectively). Available focal-point velocities ranged from 0,76 to 0,128 cm/s depending on site and season. Our findings represent one of the more rigorous field tests of an optimal foraging/habitat selection model for aquatic organisms because they encompass multiple species and years, and for one species, multiple sites. Because of the ease of parameterization of our model, it should be readily testable in a range of lotic habitats. If validated in other systems, the model should provide critical habitat information that will aid in the management of riverine systems and improve the performance of a variety of currently used management models (e.g. instream flow incremental methodology (IFIM) and total maximum daily load calculations (TMDL)). Resumen 1. Existe una grave necesidad de modelos que predigan con precisión la selección de hábitat por parte de los peces con fines que van del desarrollo de la teoría ecológica a la conservación de la biodiversidad. Nosotros hemos desarrollado un modelo nuevo y de fácil manejo de alimentación óptima para peces que se alimentan de la deriva que se fundamenta en los diferentes beneficios energéticos derivados de ocupar velocidades focales distintas en un río. 2. El modelo básico puede formularse como: Ix = (Ex * Px) = {(D * A * V) * [1/(1 + e(b + cV))]} , Sx, donde: (1) Ix es el energía neta obtenida a la velocidad, x; (2) V es la velocidad (cm/s); (3) A es el area visual de reacción del pez; (4) D es la energía contenida en las presas (J/m3) en la deriva; (5) E es la tasa de encuentro de presas; (6) P es la probabilidad de captura de la presa, que puede representarse como 1/(1 + e(b + cV)) donde b y c son constantes; y (7) S es el coste de nadar para mantener la posición en la corriente (J/s). Puesto que D, A y S pueden considerarse constantes en el rango de velocidades que ocupan estos peces, el modelo se reduce a e(b + cV) = 1/(cV , 1) que resolvimos iterativamente para obtener una velocidad focal óptima para cada especie en cada muestreo. 3. Probamos el modelo comparando su predicciones con la velocidades focales medias (i.e. microhabitats) ocupadas por cuatro especies de ciprínidos que se alimentan de la deriva en un río de Carolina del Norte. El modelo predijo con éxito las velocidades focales ocupadas por estas especies (11/14 casos) en tres muestreos estacionales llevados a cabo a lo largo de dos años en dos estaciones. Incluso las predicciones fallidas se diferenciaron en menos de 2 cm/s del límite de confianza al 95% CIs de las velocidades medias ocupadas, y la diferencia media entre predicciones y observaciones fue pequeña (rango = 0.9 cm/s warpaint shiner, a 3.3-cm/s Tennessee shiner). El rango de las velocidades focales medias disponibles fue de 0,76 cm/s a 0,128 cm/s dependiendo de la localidad y estación del año. 4. Nuestros resultados son una de las pruebas de campo más rigurosas de un modelo de alimentación óptima/selección de hábitat para organismos acuáticos puesto que incluyen diversas especies, años y, para una de las especies, localidades. La facilidad de la estima de los parámetros del modelo hace que sea fácil probarlo en diversos hábitats lóticos. Si es validado en ellos, el modelo debería proporcionar información valiosa que ayudará a la gestión de los sistemas fluviales y mejorará los resultados obtenidos a través de varios modelos usados actualmente para la gestión (p.e. IFIM y cálculos TMDL). [source] Applications of the rep-PCR DNA fingerprinting technique to study microbial diversity, ecology and evolutionENVIRONMENTAL MICROBIOLOGY, Issue 4 2009Satoshi Ishii Summary A large number of repetitive DNA sequences are found in multiple sites in the genomes of numerous bacteria, archaea and eukarya. While the functions of many of these repetitive sequence elements are unknown, they have proven to be useful as the basis of several powerful tools for use in molecular diagnostics, medical microbiology, epidemiological analyses and environmental microbiology. The repetitive sequence-based PCR or rep-PCR DNA fingerprint technique uses primers targeting several of these repetitive elements and PCR to generate unique DNA profiles or ,fingerprints' of individual microbial strains. Although this technique has been extensively used to examine diversity among variety of prokaryotic microorganisms, rep-PCR DNA fingerprinting can also be applied to microbial ecology and microbial evolution studies since it has the power to distinguish microbes at the strain or isolate level. Recent advancement in rep-PCR methodology has resulted in increased accuracy, reproducibility and throughput. In this minireview, we summarize recent improvements in rep-PCR DNA fingerprinting methodology, and discuss its applications to address fundamentally important questions in microbial ecology and evolution. [source] Mercury-induced reproductive impairment in fish,,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2009Kate L. Crump Abstract Mercury is a potent neurotoxin, and increasing levels have led to concern for human and wildlife health in many regions of the world. During the past three decades, studies in fish have examined the effects of sublethal mercury exposure on a range of endpoints within the reproductive axis. Mercury studies have varied from highly concentrated aqueous exposures to ecologically relevant dietary exposures using levels comparable to those currently found in the environment. This review summarizes data from both laboratory and field studies supporting the hypothesis that mercury in the aquatic environment impacts the reproductive health of fish. The evidence presented suggests that the inhibitory effects of mercury on reproduction occur at multiple sites within the reproductive axis, including the hypothalamus, pituitary, and gonads. Accumulation of mercury in the fish brain has resulted in reduced neurosecretory material, hypothalamic neuron degeneration, and alterations in parameters of monoaminergic neurotransmission. At the level of the pituitary, mercury exposure has reduced and/or inactivated gonadotropin-secreting cells. Finally, studies have examined the effects of mercury on the reproductive organs and demonstrated a range of effects, including reductions in gonad size, circulating reproductive steroids, gamete production, and spawning success. Despite some variation between studies, there appears to be sufficient evidence from laboratory studies to link exposure to mercury with reproductive impairment in many fish species. Currently, the mechanisms underlying these effects are unknown; however, several physiological and cellular mechanisms are proposed within this review. [source] Spatial and temporal evaluation of metal concentrations in soils and sediments from new orleans, louisiana, USA, following hurricanes Katrina and RitaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2007Michael T. Abel Abstract During January 2006, soil and sediment samples from 75 sites in the New Orleans (LA, USA) area were collected and tested for 26 inorganic elements. The study design was intended to provide a spatial pattern of metal concentrations within the city following hurricanes Katrina and Rita. The sampling design included four transects that traversed the city in a north,south direction and three transects that traversed the city in an east,west direction. Contaminant concentrations were determined at multiple sites within each transect and compared to U.S. Environmental Protection Agency soil screening criteria pertaining to human health. Concentrations of Pb and As exceeded the criteria indiscriminately throughout the city. Of the 75 sites, 14 (19%) exceeded the soil screening criteria for Pb, and 73 (97%) exceeded the criteria for As. Forty-three of the 75 sites coincided with a previous sampling event in October 2005. Metal concentrations were evaluated for temporal comparisons using a pair sampled t test. Arsenic concentrations differed significantly over time, but Pb concentrations did not. [source] Clinical research networks in diabetes: the evolving role of the research nurseEUROPEAN DIABETES NURSING, Issue 1 2007P Chester PhD Visiting Academic Abstract The importance of evidence-based care for patients with diabetes is well established, and the evidence required to make decisions about patient care is generated through research and audit. The rigours of the research process and the need to enrol large numbers of patient volunteers in a timely manner has meant that most studies are now conducted at multiple sites. Research infrastructure is costly to implement, but is important for successful clinical research projects. By establishing permanent networks this infrastructure can be maintained and built upon. Research nursing has evolved as a new but very important discipline within the nursing profession in recent years and it has been pivotal for the success of many studies. In this article we examine the potential for clinical research networks to facilitate high quality clinical research and in particular the development of the research nurse role. Copyright © 2007 FEND. [source] Meta-analysis of standardized incidence and mortality rates of childhood leukaemia in proximity to nuclear facilitiesEUROPEAN JOURNAL OF CANCER CARE, Issue 4 2007P.J. BAKER phd The meta-analysis combined and statistically analysed studies of childhood leukaemia and nuclear facilities. Focus was on studies that calculated standardized rates for individual facilities. Due to variability between study designs, eight separate analyses were performed stratified by age and zone. One hundred and thirty-six sites were used in at least one analysis. Unadjusted, fixed effects and random effects models were used. Meta-rates greater than one were found in all models at all stratification levels often achieving statistical significance. Caution must be used when interpreting these results. The meta-analysis was able to show an increase in childhood leukaemia near nuclear facilities, but does not support a hypothesis to explain the excess. Each type of model utilized has limitations. Fixed effects models give greater weight to larger studies; however, population density may be a risk factor. Random effects models give greater weight to smaller studies that may be more likely to be affected by publication bias. A limitation of the overall study design is that standardized rates must be available for individual sites which led to exclusion of studies that only calculated rates for multiple sites and those that presented other statistical methods. Further, dose-response studies do not support excess rates found near nuclear facilities. However, it cannot be ignored that the majority of studies have found elevated rates, although not usually statistically significant. [source] Click Chemistry Inspired Synthesis of Novel Ferrocenyl-Substituted Amino Acids or PeptidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2009V. Sai Sudhir Abstract This work reports on the synthesis of a wide range of ferrocenyl-substituted amino acids and peptides in excellent yield. Conjugation is established via copper-catalyzed 1,3-dipolar cycloaddition. Two complementary strategies were employed for conjugation, one involving cycloaddition of amino acid derived azides with ethynyl ferrocene 1 and the other involves cycloaddition between amino acid derived alkynes with ferrocene-derived azides 2 and 3. Labeling of amino acids at multiple sites with ferrocene is discussed. A new route to 1,1,-unsymmetrically substituted ferrocene conjugates is reported. A novel ferrocenophane 19 is accessed via bimolecular condensation of amino acid derived bis-alkyne 9b with the azide 2. The electrochemical behavior of some selected ferrocene conjugates has been studied by cyclic voltammetry.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Lessons from leeches: a call for DNA barcoding in the labEVOLUTION AND DEVELOPMENT, Issue 6 2006Alexandra E. Bely SUMMARY Many evolution of development labs study organisms that must be periodically collected from the wild. Whenever this is the case, there is the risk that different field collections will recover genetically different strains or cryptic species. Ignoring this potential for genetic variation may introduce an uncontrolled source of experimental variability, leading to confusion or misinterpretation of the results. Leeches in the genus Helobdella have been a workhorse of annelid developmental biology for 30 years. Nearly all early Helobdella research was based on a single isolate, but in recent years isolates from multiple field collections and multiple sites across the country have been used. To assess the genetic distinctness of different isolates, we obtained specimens from most Helobdella laboratory cultures currently or recently in use and from some of their source field sites. From these samples, we sequenced part of the mitochondrial gene cytochrome oxidase I (COI). Sequence divergences and phylogenetic analyses reveal that, collectively, the Helobdella development community has worked on five distinct species from two major clades. Morphologically similar isolates that were thought to represent the same species (H. robusta) actually represent three species, two of which coexist at the same locality. Another isolate represents part of a species complex (the "H. triserialis" complex), and yet another is an invasive species (H. europaea). We caution researchers similarly working on multiple wild-collected isolates to preserve voucher specimens and to obtain from these a molecular "barcode," such as a COI gene sequence, to reveal genetic variation in animals used for research. [source] E2F1-mediated transcriptional inhibition of the plasminogen activator inhibitor type 1 geneFEBS JOURNAL, Issue 18 2001Magdalena Koziczak ,Gene expression of the plasminogen activation system is cell-cycle dependent. Previously, we showed that ectopic expression of E2F1 repressed the plasminogen activator inhibitor type 1 (PAI-1) promoter in a manner dependent on the presence of DNA-binding and transactivation domains of E2F1 but independent of binding to pocket-binding proteins, suggesting a novel mechanism for E2F-mediated negative gene regulation [Koziczak, M., Krek, W. & Nagamine, Y. (2000) Mol. Cell. Biol.20, 2014,2022]. However, it remains to be seen whether endogenous E2F can exert a similar effect. We report here that down-regulation of PAI-1 gene expression correlates with an increase in endogenous E2F activity. When cells were treated with a cdk2/4-specific inhibitor, which maintains E2F in an inactive state, the decline of serum-induced PAI-1 mRNA levels was suppressed. In mutant U2OS cells expressing a temperature-sensitive retinoblastoma protein (pRB), a shift to a permissive temperature induced PAI-1 mRNA expression. In U2OS cells stably expressing an E2F1-estrogen receptor chimeric protein that could be activated by tamoxifen, PAI-1 gene transcription was markedly reduced by tamoxifen even in the presence of cycloheximide. These results all indicate that endogenous E2F can directly repress the PAI-1 gene. DNase I hypersensitive-site analysis of the PAI-1 promoter suggested the involvement of conformation changes in chromatin structure of the PAI-1 promoter. 5, deletion analysis of the PAI-1 promoter showed that multiple sites were responsible for the E2F negative regulation, some of which were promoter dependent. Interestingly, one of these sites is a p53-binding element. [source] Biodiversity of Belgian groundwater fauna in relation to environmental conditionsFRESHWATER BIOLOGY, Issue 4 2009PATRICK MARTIN Summary 1. The Pleistocene glaciations during the Quaternary appear to have resulted in an impoverished groundwater fauna in northern Europe. Re-colonisation may have occurred either through long-distance dispersal from unglaciated southern areas or from local refugia. 2. The Belgian groundwater fauna was sampled at multiple sites, and its habitats characterised, to assess whether the composition of present-day stygobiotic assemblages can be attributed to either of these mechanisms. 3. A total of 202 sampling sites were selected in four hydrogeographic units of the Meuse River catchment. Sites were equally divided among the saturated and unsaturated zones of fractured aquifers (karst) and within the hyporheic and phreatic zones of porous aquifers. Seventeen environmental parameters were determined in parallel. 4. More than 140 species were recorded, including representatives of the Amphipoda, Cladocera, Copepoda, Hydrachnidia, Isopoda, Oligochaeta, Ostracoda, Mollusca, Syncarida and Nematoda. Thirty stygobiont species were identified, of which 10 species were new to the Belgian fauna, raising the total number of stygobiotic species in Belgium to 41. 5. The frequency of occurrences of stygobiotic species was always low, with 37% of the sampled sites lacking stygobionts. A few species were exclusive to one hydrological zone, although no statistically significant differences were detected in species richness at any of the four hierarchial levels considered (Meuse catchment = region, hydrogeographic units, aquifer type and hydrological zone). 6. Overall, results suggest that the stygobiotic fauna of Belgium is species-poor and mostly comprises widely distributed species with broad ecological tolerances. This supports the view that eurytopic species re-colonised the area by long-distance dispersal from refugia in southern Europe. The virtual absence of endemic species further suggests that the scenario of an ancient fauna that survived in local refugia is of minor importance. [source] FEIBA® in treatment of acute bleeding episodes in patients with haemophilia A and factor VIII inhibitors: a retrospective survey in regional haemophilia centreHAEMOPHILIA, Issue 3 2009P. SMEJKAL Summary., FEIBA® (factor eight inhibitor by-passing activity) is used to achieve haemostasis in haemophiliacs with inhibitor. The aim of this study was to evaluate efficacy and consumption of the product in treatment of haemorrhages in haemophiliacs with factor VIII inhibitor, and determine factors that can influence the results of treatment. We used data from our haemophilia centre from years 2000,2008. Six haemophiliacs with factor VIII inhibitor were treated on demand with FEIBA® for 61 bleeding episodes (45 haemarthroses, six muscle bleeds, six other sites bleeds and four multiple sites bleeds). The median cumulative dose of FEIBA® per bleeding episode was 205 U kg,1. Bleeding was stopped in 96.7% (59 of 61) of events but re-bleeding occurred in 3 events (4.9%) within 48 h after cessation of bleeding. In home treatment (20 of 61) bleeding stopped in 90% (18 of 20) without recurrence and the median consumption per event was reduced to 153 U kg,1. Without the use of home treatment the median consumption was 250 U kg,1 per event and bleeding ceased definitely in 92.7% (38 of 41) of cases. The cumulative dose of FEIBA® was lower for three episodes with re-bleeding: median 96 U kg,1 but not in the two cases of ineffective treatment: 361 U kg,1. FEIBA® in management of bleeding episodes completely resolved the haemorrhage in 91.8% of events and in a further 4.9% if treatment was restarted. Using home treatment saved expenditure due to the lower cumulative dose needed for treatment of haemorrhage. [source] Transmembrane adapters: attractants for cytoplasmic effectorsIMMUNOLOGICAL REVIEWS, Issue 1 2003Jonathan A. Lindquist Summary: Transmembrane adapter proteins (TRAPs) are a relatively new and growing family of proteins that include linker for activation of T cells (LAT), phosphoprotein associated with glycosphingolipid-enriched micro domains (PAG)/C-terminal Src kinase (Csk) binding protein (Cbp), SHP2-interacting transmembrane adapter protein (SIT), T cell receptor interacting molecule (TRIM), and the recently identified non-T cell activation linker (NTAL) and pp30. TRAPs share several common structural features, but more importantly they possess multiple sites of tyrosine phosphorylation, by which they act as scaffolds for recruiting cytosolic adapter and/or effector proteins. The membrane association of TRAPs places them near to the immunoreceptors, a position from which they coordinate and modulate the signals they receive to produce an appropriate cellular response. [source] The extraordinary ligand binding properties of human serum albuminIUBMB LIFE, Issue 12 2005Mauro Fasano Abstract Human serum albumin (HSA), the most prominent protein in plasma, binds different classes of ligands at multiple sites. HSA provides a depot for many compounds, affects pharmacokinetics of many drugs, holds some ligands in a strained orientation providing their metabolic modification, renders potential toxins harmless transporting them to disposal sites, accounts for most of the antioxidant capacity of human serum, and acts as a NO-carrier. The globular domain structural organization of monomeric HSA is at the root of its allosteric properties which are reminiscent of those of multimeric proteins. Here, structural, functional, biotechnological, and biomedical aspects of ligand binding to HSA are summarized. [source] Nitric Oxide, Mitochondria, and Cell DeathIUBMB LIFE, Issue 3-5 2001Guy C. Brown Abstract NO or its derivatives (reactive nitrogen species: RNS) have three types of actions on mitochondria: 1) reversible inhibition of mitochondrial respiration at cytochrome oxidase by NO, and irreversible inhibition at multiple sites by RNS; 2) stimulation of mitochondrial production of superoxide, hydrogen peroxide, and peroxynitrite by NO; and 3) induction of mitochondrial permeability transition (MPT) by RNS. Similarly there are three main roles of mitochondria in NO-induced cell death: a) NO inhibition of respiration can induce necrosis (or excitotoxicity in neurons) and inhibit apoptosis if glycolysis is insufficient to compensate, b) RNS- or oxidant-induced signal transduction or DNA damage may activate the mitochondrial pathway to apoptosis, and c) RNS-induced MPT may induce apoptosis or necrosis. [source] National-scale metacommunity dynamics of carabid beetles in UK farmlandJOURNAL OF ANIMAL ECOLOGY, Issue 2 2008David R. Brooks Summary 1Understanding the wide-scale processes controlling communities across multiple sites is a foremost challenge of modern ecology. Here, data from a nation-wide network of field sites are used to describe the metacommunity dynamics of arable carabid beetles. This is done by modelling how communities are structured at a local level, by changes in the environment of the sampled fields and, at a regional level, by fitting spatial parameters describing latitudinal and longitudinal gradients. 2Local and regional processes demonstrated independent and significant capacities for structuring communities. Within the local environment, crop type was found to be the primary determinant of carabid community composition. The regional component included a strong response to a longitudinal gradient, with significant increases in diversity in an east-to-west direction. 3Carabid metacommunities seem to be structured by a combination of species sorting dynamics, operating at two different, but equally important, spatial scales. At a local scale, species are sorted along a resource gradient determined by crop type. At a wider spatial scale species appear to be sorted along a longitudinal gradient. 4Nation-wide trends in communities coincided with known gradients of increased homogeneity of habitat mosaics and agricultural intensification. However, more work is required to understand fully how communities are controlled by the interaction of crops with changes in landscape structure at different spatial scales. 5We conclude that crop type is a powerful determinant of carabid biodiversity, but that it cannot be considered in isolation from other components of the landscape for optimal conservation policy. [source] Fish assemblages of the Casiquiare River, a corridor and zoogeographical filter for dispersal between the Orinoco and Amazon basinsJOURNAL OF BIOGEOGRAPHY, Issue 9 2008Kirk O. Winemiller Abstract Aim, The aim of this study was to determine whether the Casiquiare River functions as a free dispersal corridor or as a partial barrier (i.e. filter) for the interchange of fish species of the Orinoco and Negro/Amazon basins using species assemblage patterns according to geographical location and environmental features. Location, The Casiquiare, Upper Orinoco and Upper Negro rivers in southern Venezuela, South America. Methods, Our study was based on an analysis of species presence/absence data and environmental information (11 habitat characteristics) collected by the authors and colleagues between the years 1984 and 1999. The data set consisted of 269 sampled sites and 452 fish species (> 50,000 specimens). A wide range of habitat types was included in the samples, and the collection sites were located at various points along the entire length of the Casiquiare main channel, at multiple sites on its tributary streams, as well as at various nearby sites outside the Casiquiare drainage, within the Upper Orinoco and Upper Rio Negro river systems. Most specimens and field data used in this analysis are archived in the Museo de Ciencias Naturales in Guanare, Venezuela. We performed canonical correspondence analysis (CCA) based on species presence/absence using two versions of the data set: one that eliminated sites having < 5 species and species occurring at < 5 sites; and another that eliminated sites having < 10 species and species occurring at < 10 sites. Cluster analysis was performed on sites based on species assemblage similarity, and a separate analysis was performed on species based on CCA loadings. Results, The CCA results for the two versions of the data set were qualitatively the same. The dominant environmental axis contrasted assemblages and sites associated with blackwater vs. clearwater conditions. Longitudinal position on the Casiquiare River was correlated (r2 = 0.33) with CCA axis-1 scores, reflecting clearwater conditions nearer to its origin (bifurcation of the Orinoco) and blackwater conditions nearer to its mouth (junction with the Rio Negro). The second CCA axis was most strongly associated with habitat size and structural complexity. Species associations derived from the unweighted pair-group average clustering method and pair-wise squared Euclidean distances calculated from species loadings on CCA axes 1 and 2 showed seven ecological groupings. Cluster analysis of species assemblages according to watershed revealed a stronger influence of local environmental conditions than of geographical proximity. Main conclusions, Fish assemblage composition is more consistently associated with local environmental conditions than with geographical position within the river drainages. Nonetheless, the results support the hypothesis that the mainstem Casiquiare represents a hydrochemical gradient between clearwaters at its origin and blackwaters at its mouth, and as such appears to function as a semi-permeable barrier (environmental filter) to dispersal and faunal exchanges between the partially vicariant fish faunas of the Upper Orinoco and Upper Negro rivers. [source] Childhood Fractures Are Associated With Decreased Bone Mass Gain During Puberty: An Early Marker of Persistent Bone Fragility?,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2006Serge L Ferrari MD Abstract Whether peak bone mass is low among children with fractures remains uncertain. In a cohort of 125 girls followed over 8.5 years, 42 subjects reported 58 fractures. Among those, BMC gain at multiple sites and vertebral bone size at pubertal maturity were significantly decreased. Hence, childhood fractures may be markers of low peak bone mass acquisition and persistent skeletal fragility. Introduction: Fractures in childhood may result from a deficit in bone mass accrual during rapid longitudinal growth. Whether low bone mass persists beyond this period however remains unknown. Materials and Methods: BMC at the spine, radius, hip, and femur diaphysis was prospectively measured over 8.5 years in 125 girls using DXA. Differences in bone mass and size between girls with and without fractures were analyzed using nonparametric tests. The contribution of genetic factors was evaluated by mother-daughter correlations and that of calcium intake by Cox proportional hazard models. Results: Fifty-eight fractures occurred in 42 among 125 girls (cumulative incidence, 46.4%), one-half of all fractures affecting the forearm and wrist. Girls with and without fractures had similar age, height, weight. and calcium intake at all time-points. Before and during early puberty, BMC and width of the radius diaphysis was lower in the fracture compared with no-fracture group (p < 0.05), whereas aBMD and BMAD were similar in the two groups. At pubertal maturity (Tanner's stage 5, mean age ± SD, 16.4 ± 0.5 years), BMC at the ultradistal radius (UD Rad.), femur trochanter, and lumbar spine (LS), and LS projected bone area were all significantly lower in girls with fractures. Throughout puberty, BMC gain at these sites was also decreased in the fracture group (LS, ,8.0%, p = 0.015; UD Rad., ,12.0%, p = 0.004; trochanter, ,8.4%, p = 0.05 versus no fractures). BMC was highly correlated between prepuberty and pubertal maturity (R = 0.54,0.81) and between mature daughters and their mothers (R = 0.32,0.46). Calcium intake was not related to fracture risk. Conclusions: Girls with fractures have decreased bone mass gain in the axial and appendicular skeleton and reduced vertebral bone size when reaching pubertal maturity. Taken together with the evidence of tracking and heritability for BMC, these observations indicate that childhood fractures may be markers for low peak bone mass and persistent bone fragility. [source] Development of an Optrode for Intramural Multisite Optical Recordings of Vm in the HeartJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2003JONATHAN L. BYARS M.S. Introduction: Optical mapping of transmembrane potential (Vm) is an important tool in the investigation of impulse propagation in the heart. It provides valuable information about spatiotemporal changes of Vm that cannot be obtained by other techniques, but it presently is limited to measurements from the heart surfaces. Therefore, the goal of this work was to develop a technique for intramural multisite optical measurements of Vm using fiberoptic technology. Methods and Results: An optrode, a bundle of thin optical fibers, was developed for measuring intramural optical signals at multiple sites in the heart. The optrode consisted of seven fibers with diameter of 225 ,m arranged in a hexagonal pattern that were used to deliver excitation light to the myocardium, to collect the emitted fluorescence, and to project the light onto a 16 × 16 array of photodiode detectors. Rabbit hearts were stained with the Vm -sensitive dye RH-237. Fluorescence was excited using a 100-W Hg lamp. Intramural action potentials were recorded at multiple sites separated by 2 mm inside the left ventricle. Signal-to-noise (RMS) ratio was 21.2 ± 12 (n = 7) without averaging or ratiometry and with negligible cross-talk (<1.9%) between the neighboring photodiodes. The size of the recording area for an individual fiber was estimated at approximately 0.8 mm. Conclusion: These data demonstrate feasibility of multisite transmural measurements of Vm without signal averaging and ratiometry. This technique might become useful in studies of transmural impulse conduction during arrhythmias and defibrillation. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1196-1202, November 2003) [source] Focal Origin of Atrial Tachycardia in Dogs with Rapid Ventricular Pacing-Induced Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2003GUILHERME FENELON M.D. Introduction: Dogs with rapid ventricular pacing-induced congestive heart failure (CHF) have inducible atrial tachycardia (AT), with a mechanism consistent with delayed afterdepolarization-mediated triggered activity. We assessed the hypothesis that AT has a focal origin. Methods and Results: Twenty-one CHF dogs undergoing 3 to 4 weeks of ventricular pacing at 235 beats/min were studied. Biatrial epicardial mapping of 20 sustained AT episodes (cycle length [CL], 175 ± 53 msec) in 5 dogs revealed an area of earliest activation in the right atrial (RA) free wall (13 episodes), RA appendage (4 episodes), or between the pulmonary veins (3 episodes). Total epicardial activation time during AT (73 ± 19 msec) was similar to that during sinus rhythm (72 ± 13 msec) and on average was <50% of the AT CL. Higher-density mapping of the RA free wall during 30 sustained AT episodes (163 ± 55 msec) in 9 dogs identified a site of earliest activation along the sulcus terminalis most frequently as a stable, focal activation pattern from a single site. Endocardial mapping of 49 sustained AT episodes (156 ± 27 msec) in 10 dogs revealed multiple sites of AT origin arising along the crista terminalis and pulmonary veins. Right and left ATs were terminated with discrete radiofrequency ablation, but other ATs remained inducible. A rapid, left AT generating an ECG pattern of atrial fibrillation was ablated inside the pulmonary vein. Conclusion: AT induced in this CHF model after 3 to 4 weeks of rapid ventricular pacing has an activation pattern consistent with a focal origin. Sites of earliest activation are distributed predominately along the crista terminalis and within or near the pulmonary veins. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***-***, October 2003) [source] Considering a multisite study?JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 2 2002How to take the leap, have a soft landing Although most policymakers agree that a fundamental goal of the mental health system is to provide integrated community-based services, there is little empirical evidence with which to plan such a system. Studies in the community mental health literature have not used a standard set of evaluation methods. One way of addressing this gap is through a multisite program evaluation in which multiple sites and programs evaluate the same outcomes using the same instruments and time frame. The proposition of introducing the same study design in different settings and programs is deceptively straightforward. The difficulty is not in the conceptualization but in the implementation. This article examines the factors that act as implementation barriers, how are they magnified in a multisite study design, and how they can be successfully addressed. In discussing the issue of study design, this article considers processes used to address six major types of barriers to conducting collaborative studies identified by Lancaster or Lancaster's six Cs,contribution, communication, compatibility, consensus, credit, and commitment. A case study approach is used to examine implementation of a multisite community mental health evaluation of services and supports (case management, self-help initiatives, crisis interventions) represented by six independent evaluations of 15 community health programs. A principal finding was that one of the main vehicles to a successful multisite project is participation. It is only through participation that Lancaster's six Cs can be addressed. Key factors in large, geographically dispersed, and diverse groups include the use of advisory committees, explicit criteria and opportunities for participation, reliance on all modes of communication, and valuing informal interactions. The article concludes that whereas modern technology has assisted in making complicated research designs feasible, the operationalization of timeless virtues such as mutual respect and trust, flexibility, and commitment make them successful. © 2002 John Wiley & Sons, Inc. 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