Distribution by Scientific Domains

Kinds of Wells

  • GaA quantum well
  • asymmetric double quantum well
  • deep well
  • double quantum well
  • ingan quantum well
  • ingan/gan quantum well
  • monitoring well
  • multiple quantum well
  • observation well
  • quantum well
  • semiconductor quantum well
  • single quantum well
  • supply well
  • water well

  • Terms modified by Wells

  • well being
  • well known

  • Selected Abstracts

    Airway inflammation in employees involved in cultivating Japanese mushrooms (bunashimeji)

    RESPIROLOGY, Issue 4 2008
    Kenji TSUSHIMA
    Background and objective: Chronic inhalation of spores may cause respiratory symptoms such as productive cough and sputum. The purpose of this study was to determine the clinical pathophysiology of airway inflammation caused by bunashimeji spores and to investigate whether the spores have direct toxic inflammatory effects. Methods: Sensitized employees with respiratory symptoms and a stimulation index (SI) > 200%, and non-sensitized employees with a SI < 200% were enrolled. They underwent sputum induction and chest high-resolution computed tomography (HRCT). The in vitro effect of bunashimeji spore solutions on normal human bronchial epithelial (NHBE) cell cultures was investigated using the air,liquid interface method. Bunashimeji spore solution was added at 104 or 106 spores per 20 ,L/well. The interleukin (IL)-8 and epithelial neutrophil-activating peptide-78 (ENA-78) concentrations in the medium and IL-8 mRNA expression of NHBE cells were assessed after each stimulation. Results: Sensitized employees were divided into 14 with normal HRCT and 9 with abnormal HRCT. Fifteen of the sensitized group and five of the non-sensitized group had a productive cough and sputum. The neutrophil counts in induced sputum were significantly higher in subjects with abnormal HRCT than in those with normal HRCT. IL-8 and ENA-78 concentrations following stimulation with 104 and 106 spores were significantly increased compared with PBS only on day 9. IL-8 mRNA expression due to spore stimulation was significantly increased compared with control. IL-8 mRNA expression with 106 spore stimulation was significantly increased on days 6 and 12 compared with 104 spores. Conclusion: The inhalation of spores directly produces toxic inflammatory effects in the airways, independent of the degree of sensitization. [source]

    They Don't Do It Often, But They Do It Well: Exploring the relationship between applicant mental abilities and faking

    Julia Levashina
    Despite its scientific and practical importance, relatively few studies have been conducted to investigate the relationship between job applicant mental abilities and faking. Some studies suggest that more intelligent people fake less because they do not have to. Other studies suggest that more intelligent people fake more because they have increased capacity to fake. Based on a model of faking likelihood, we predicted that job candidates with a high level of mental abilities would be less likely to fake a biodata measure. However, for candidates who did exhibit faking on the biodata measure, we expected there would be a strong positive relationship between mental abilities and faking, because mental abilities increase their capacity to fake. We found considerable support for hypotheses on a large sample of job candidates (N=17,368), using the bogus item technique to detect faking. [source]

    Data Revisions Are Not Well Behaved

    forecasting; news and noise; real-time data; NIPA variables We document the empirical properties of revisions to major macroeconomic variables in the United States. Our findings suggest that they do not satisfy simple desirable statistical properties. In particular, we find that these revisions do not have a zero mean, which indicates that the initial announcements by statistical agencies are biased. We also find that the revisions are quite large compared to the original variables and they are predictable using the information set at the time of the initial announcement, which means that the initial announcements of statistical agencies are not rational forecasts. [source]

    Recognizing Dr. Ting-Kai Li for a Job Well Done

    ALCOHOLISM, Issue 12 2008
    Ivan Diamond Editor in Chief
    No abstract is available for this article. [source]

    Taking Animals Seriously: William Wordsworth and the Claims of Ecological Romanticism

    ORBIS LITERARUM, Issue 4 2000
    Peter Mortensen
    Critics have long been aware that William Wordsworth borrowed from the German balladist Gottfried August Bürger in composing Lyrical Ballads (1798/1800). Wordsworth was both attracted and repulsed by Bürger's sensational and sensationally popular verse, yet the reason for this ambiguity has continued to baffle scholars. In this essay I turn to ecological criticism to cast a new light on the intertextual and cross-cultural exchange between Bürger's "Der Wilde Jäger" and Wordsworth's "Hart-Leap Well". Wordsworth, I claim, was intrigued by Bürger's attempt to write a poem about hunting, yet in rewriting the German ballad Wordsworth also seeks to shift the emphasis somewhat, in such a way as to focus more explicitly on what he believed to be the main issue at stake: man's shockingly cruel treatment of animals. In thus reconceptualising Bürger's poem, Wordsworth inaugurates a new kind of Romantic nature poetry, which brings animals into the foreground and takes their suffering seriously. In the essay's final section, I defend Wordsworth's proto-ecological vision against critics who believe that Wordsworth's love of nature caused him to lose interest in mankind. Far from leading necessarily to misanthropy or disillusionment, I argue, the vision propounded in ,Hart-Leap Well' invites us to speculate how we can combine concern for the environment with a concern for our fellow men. [source]


    PALAEONTOLOGY, Issue 5 2006
    Abstract:, A new species of primitive bandicoot, Yarala kida sp. nov., is described from Kangaroo Well, a site in the Northern Territory of Australia. This species is possibly ancestral to Yarala burchfieldi, the type species of the Yaraloidea, and supports a late Oligocene age for the Kangaroo Well Local Fauna. The yaraloid bandicoots are likely to become important biochronological tools for Australian faunas of late Oligocene to early Miocene age, as they are widespread and diverse. Developing morphoclines for this group is therefore essential, as is publication of the mostly undescribed bandicoot material known from other sites of similar age. [source]

    Effects of lattice-mismatch induced built-in strain on the valence band properties of wurtzite ZnO/Zn1,xMgxO quantum well heterostructures

    K. Zitouni
    Abstract We present a theoretical study of the effects of lattice-mismatch induced built-in strain on the electronic properties of valence band states in wurtzite ZnO/Zn1,xMgxO Quantum Well (QW) heterostructures. In this purpose, a 6x6 k·p method has been used to incorporate the effects of strain and nonparabolicity. The energies corresponding to the transitions between conduction band (C), heavy hole (HH), light hole (LH) and crystal-field split-off hole (CH) bands have been calculated as a function of Mg composition and strain. We have also calculated the energy dispersions and wave functions of strained wurtzite ZnO. It is found that ZnO is always under a biaxial tensile strain, in the whole Mg composition range investigated (x < 40%). As a consequence, the light hole valence subband is shifted upwards with respect to the corresponding heavy hole valence subband, resulting in a reduction of ZnO direct band gap by almost 6% when x = 35%. This is found to result in turn in a significantly reduced in-plane hole effective mass at the top of the valence band which is always LH-like. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Patients' Knowledge about Risk Factors for Erectile Dysfunction is Poor

    Martin K. Baumgartner MD
    ABSTRACT Introduction., Well informed and educated patients ideally manage to prevent or delay the onset of severe chronic diseases. With respect to erectile dysfunction (ED) this is of importance because ED is considered to herald debilitating cardiovascular diseases like coronary artery disease. Aim., This survey aimed to assess patient's knowledge about risk factors (RF) for ED and to identify their preferred source of information. Main Outcome Measures., Knowledge of RF for ED and sources used to gather information about ED as reported by patients with ED. Methods., Between July 2004 and June 2006, 126 patients who presented at our outpatient clinic for an assessment of their ED were prospectively evaluated. The patients received a questionnaire about their demographic and socioeconomic circumstances, their strategies to gather information about ED, and their knowledge of specific RF for this disease. The questionnaire was completed by 81 patients (64%). Results., Forty-one patients (51%) could not name one single RF for ED. Three men knew more than three RF. The two most popular sources of information were the Internet and general practitioners. Well-educated patients were significantly better informed than others. Patients using the Internet as source for health information were significantly younger and had a better knowledge about RF for ED compared to those not using the Internet. Conclusions., Patients' knowledge about RF for ED is poor. The Internet seems to be the most useful information source for patients with ED and is predominantly used by younger and better educated patients. Given that ED is considered to be a precursor lesion of severe cardiovascular diseases, patient information and education deserves more attention. Baumgartner MK, Hermanns T, Cohen A, Schmid DM, Seifert B, Sulser T, and Strebel RT. Patients' knowledge about risk factors for erectile dysfunction is poor. J Sex Med 2008;5:2399,2404. [source]

    PELD: Working Well, But Only Half of the Time?

    John C. Magee
    No abstract is available for this article. [source]

    I,Virtues of Art and Human Well -Being

    Peter Goldie
    What is the point of art, and why does it matter to us human beings? The answer that I will give in this paper, following on from an earlier paper on the same subject, is that art matters because our being actively engaged with art, either in its production or in its appreciation, is part of what it is to live well. The focus in the paper will be on the dispositions,the virtues of art production and of art appreciation,that are necessary for this kind of active engagement with art. To begin with, I will argue that these dispositions really are virtues and not mere skills. Then I will show how the virtues of art, and their exercise in artistic activity, interweave with the other kinds of virtue which are exercised in ethical and contemplative activity. And finally, I will argue that artistic activity affords, in a special way, a certain kind of emotional sharing that binds us together with other human beings. [source]

    Childhood Leukemia Survivors Generally Do Well: Radiation Most Problematic Factor for Those in Long-Term Remission

    Article first published online: 31 DEC 200
    No abstract is available for this article. [source]

    Robert Rosen, His Students and His Colleagues: A Glimpse into the Past and the Future as Well

    Donald C. Mikulecky
    No abstract is available for this article. [source]

    The Dodo Bird Verdict Is Alive and Well,Mostly

    Lester Luborsky
    We examined 17 meta-analyses of comparisons of active treatments with each other, in contrast to the more usual comparisons of active treatments with controls. These meta-analyses yielded a mean uncorrected absolute effect size for Cohen's d of .20, which is small and non-significant (an equivalent Pearson's r would be. 10). The smallness of this effect size confirms Rosenzweig's supposition in 1936 about the likely results of such comparisons. In the present sample, when such differences were corrected for the therapeutic allegiance of the researchers involved in comparing the different psychotherapies, these differences tend to become even further reduced in size and significance, as shown previously by Luborsky, Diguer, Seligman, et al. (1999). [source]

    Taking Animals Seriously: William Wordsworth and the Claims of Ecological Romanticism

    ORBIS LITERARUM, Issue 4 2000
    Peter Mortensen
    Critics have long been aware that William Wordsworth borrowed from the German balladist Gottfried August Bürger in composing Lyrical Ballads (1798/1800). Wordsworth was both attracted and repulsed by Bürger's sensational and sensationally popular verse, yet the reason for this ambiguity has continued to baffle scholars. In this essay I turn to ecological criticism to cast a new light on the intertextual and cross-cultural exchange between Bürger's "Der Wilde Jäger" and Wordsworth's "Hart-Leap Well". Wordsworth, I claim, was intrigued by Bürger's attempt to write a poem about hunting, yet in rewriting the German ballad Wordsworth also seeks to shift the emphasis somewhat, in such a way as to focus more explicitly on what he believed to be the main issue at stake: man's shockingly cruel treatment of animals. In thus reconceptualising Bürger's poem, Wordsworth inaugurates a new kind of Romantic nature poetry, which brings animals into the foreground and takes their suffering seriously. In the essay's final section, I defend Wordsworth's proto-ecological vision against critics who believe that Wordsworth's love of nature caused him to lose interest in mankind. Far from leading necessarily to misanthropy or disillusionment, I argue, the vision propounded in ,Hart-Leap Well' invites us to speculate how we can combine concern for the environment with a concern for our fellow men. [source]

    Drilling in the Cathedral

    DIALOG, Issue 3 2003
    Larry Rasmussen
    Abstract Utilitarianism, alienation, consumerism, and oppression are major forces endangering Earth's well-being. Over and against these morally and ecologically destructive forces are practices and ideas rooted and nourished in both ancient and modern religio-moral institutions and traditions. As powerful voices of faith calling the present to account, sacramentalism, mysticism, asceticism, and prophetic liberative practices offer Earth-honoring ways of life that draw from shared wells and deep-running waters. [source]

    Flow-Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

    ELECTROANALYSIS, Issue 24 2009
    Abstract Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine-methacrylic and/or acrylic acid-ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH,6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, long-term stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0×10,6,1.0×10,2mol L,1 and 1.0×10,5,1.0×10,2 mol L,1 with slopes of about 61.3,55.7,mV decade,1; respectively. Sensors exhibit detection limits of 1.2×10,6 and 8.2×10,6 mol L,1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within-day repeatability, between-day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow-through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method. [source]

    Development of Live Cell Chips to Monitor Cell Differentiation Processes

    C. Maercker
    Abstract A big demand exists for high-throughput functional in vitro assays which can measure cellular phenotypes by molecular methods and therefore improve the resources of primary cells for cell therapy, tissue engineering and high-content screenings in drug development. This approach focuses on cellular adhesion which is an important differentiation process during homing of stem cells. Moreover, it is a promising method especially for adherent cells which are not accessible by classical cell sorting methods. The chip design includes a housing with electrodes to measure electric field densities and impedance, respectively. Moreover, specific coatings of the wells permit a perfect growth of the selected cell types. In parallel, protein biomarkers can be followed by light microscopy. So far, experiments have been started to discriminate between different cell densities and cell types. In addition, after stimulating human cardiac fibroblasts and human umbilical vein endothelial cells, concentrations of proteins involved in adhesion had been increased, and proteins were translocated within the cells. In ongoing experiments, different human cell lines and fibroblastoid mesenchymal stem cells isolated from fat tissue, umbilical cord, or bone marrow are tested in the chip. To optimize the adhesion conditions, the surfaces within the vials of the chip were specifically activated. Microscopy was adjusted to be able to measure cellular morphology in parallel. This concept allows to identify the behavior of mesenchymal stem cells, which cannot be described so far by standard biomarkers. In addition, simulation of the homing process of the cells within its stem cell niche in an in vitro assay is a promising setup for large-scale gain-of-function or loss-of-function screenings in functional genomics as well as for generating precursor cells relevant for the therapy of various diseases. [source]

    Disruption effects of monophthalate exposures on inter-Sertoli tight junction in a two-compartment culture model

    Yun-Hui Zhang
    Abstract Phthalates are suspect environmental endocrine disruptors that may affect male reproduction and development by disturbing androgen synthesis and cell,cell interactions in the seminiferous epithelium. The in vivo metabolites, monophthalates, are thought to be the active agents, and toxicant effects including testicular damage and decreased sperm motility have been described previously. In this study, the aim was to investigate the effect of monophthalates on Sertoli cells using a two-compartment cell culture model, asking whether tight junction protein structures are affected, compromising the blood-testis barrier and contributing to male-mediated toxicity. Sertoli cells were isolated from Sprague Dawley rat testes and seeded onto the filters of two-compartment wells. A Sertoli cell monolayer was allowed to form, whereupon the cultures were treated with 0, 10, 30, 150, and 600 ,mol/L monobutyl phthalate (MBP) or mono-2-ethylhexyl phthalate (MEHP) for 24 h. Effects on the tight junctions between adjacent Sertoli cells were studied by light and transmission electron microscopy, the transepithelial electrical resistance (TEER) assay, and immunofluorescence localization. Results showed that exposures to monophthalates destroyed tight junctional structure in Sertoli cell monolayers in a dose-depended manner, as evidenced by a loss of single-cell layer organization in the cultures, decline of TEER value, and decreased expression of proteins associated with tight junctions such as zonula occludens-1 (ZO-1), F-actin, and Occludin. The changes were observed at doses of 150 and 600 ,mol/L, which is 10,100 times higher relative to estimated human exposures from the environment. These results are consistent with monophthalate-induced damage to tight junctions between adjacent Sertoli cells, suggesting that damage to Sertoli cell tight junctions induced by monophthalates may be an underlying mechanism of their male-mediated reproductive toxicity. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source]

    Immunocompetence of bivalve hemocytes as evaluated by a miniaturized phagocytosis assay

    C. Blaise
    Abstract Immune function in bivalves can be adversely affected by long-term exposure to environmental contaminants. Investigating alterations in immunity can therefore yield relevant information about the relationship between exposure to environmental contaminants and susceptibility to infectious diseases. We have developed a rapid, cost-effective, and miniaturized immunocompetence assay to evaluate the phagocytic activity, viability, and concentration of hemocytes in freshwater and marine bivalves. Preliminary experiments were performed to optimize various aspects of the assay including 1) the time required for adherence of hemocytes to polystyrene microplate wells, 2) the time required for internalization of fluorescent bacteria, 3) the ratio of hemocytes to fluorescent bacteria in relation to phagocytosis, 4) hemolymph plasma requirements, and 5) the elimination of fluorescence from (noninternalized) bacteria adhering to the external surface of hemocytes. The results of these experiments showed the optimal adherence time for hemocytes in microplate wells to be 1 h, that phagocytosis required at least 2 h of contact with fluorescently labeled E. coli cells, that the number of fluorescent E. coli cells had a positive effect on phagocytic activity, that at least 2.5 million cells/mL were required to measure a significant intake, and that a linear increase in uptake of bacteria (R = 0.91; p < 0.01) could be obtained with concentrations of up to 1.3 × 106 hemocytes/mL. Afterward, the assay was used in two field studies to identify sites having the potential to affect the immunocompetence of bivalves. The first study was conducted on Mya arenaria clams collected at selected contaminated sites in the Saguenay River (Quebec, Canada), and the second examined Elliptio complanata freshwater bivalves that had been exposed to a municipal effluent plume in the St. Lawrence River (Quebec, Canada). In the Saguenay River field study a significant increase in phagocytosis was observed at sites closest to polluted areas. Phagocytotic activity varied over time and was highest during the warmest months (June, July, and August), closely paralleling the spawning period of Mya arenaria clams. In contrast, a drop in phagocytic activity was observed in Elliptio complanata mussels exposed to surface water 4 km downstream of a major municipal effluent plume, with a concomitant increase in the number of hemocytes in the hemolymph. It appears that both immunosuppressive and immunostimulative effects are likely to occur in the field and that responses will be influenced by the type and intensity of contaminants at play. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 160,169, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10047 [source]

    Methyl- tert -hexyl ether and methyl- tert -octyl ether as gasoline oxygenates: Anticipating widespread risks to community water supply wells,

    Jeff Snelling
    Abstract The widespread contamination of groundwater resources associated with methyl- tert -butyl ether (MtBE) use has prompted a search for replacement oxygenates in gasoline. Among the alternatives currently under development are higher methyl- tert -alkyl ethers, notably methyl- tert -hexyl ether (MtHxE) and methyl- tert -octyl ether (MtOcE). As was the case with MtBE, the introduction of these ethers into fuel supplies guarantees their migration into groundwater resources. In the present study, a screening-level risk assessment compared predicted well water concentrations of these ethers to concentrations that might cause adverse effects. A physicochemical model which has been successfully applied to the prediction of MtBE concentrations in community water supply wells (CSWs) was used to predict well water concentrations of MtHxE and MtOcE. The results indicate that these ethers are likely to contaminate water supply wells at slightly lower levels than MtBE as a result of migrating from leaking underground fuel tanks to CSWs. Because very little data is available on the physicochemical and environmental properties of MtHxE and MtOcE, estimation methods were employed in conjunction with the model to predict well water concentrations. Model calculations indicated that MtHxE and MtOcE will be present in many CSWs at concentrations approaching the concentrations that have caused widespread public health concern for MtBE. Based on these results and the possibility that MtHxE and MtOcE are potential carcinogens, testing of the toxicological properties of these ethers is recommended before they are used to replace MtBE in gasoline. [source]

    Development of a solvent-free, solid-phase in vitro bioassay using vertebrate cells

    Stephanie K. Bopp
    Abstract Miniaturized bioassays offer many advantages in exploring the toxic potential of chemicals, including small sample volumes and compatibility with high-throughput screening. One problem common to miniaturized systems, however, is the loss of test chemicals because of sorption. The idea of the current study was to use the sorption phenomenon in a positive way. It was found that contaminants sorbed to the growth surface in wells of tissue-culture plates or to the surface of selected sorbent bead materials are available to vertebrate cells growing in direct contact with the contaminant-coated surface. The use of beads provided more flexibility with regard to surface area, materials, and assay format. Biosilon, a bead cell-culture carrier made of polystyrene, was found to be most suitable. It supported cell adherence and allowed the detection of reproducible dose-response curves of an increase in cytochrome CYP1A enzyme activity by sorbed polycyclic aromatic hydrocarbons in the rainbow trout (Oncorhynchus mykiss) liver cell line, RTL-W1. The resulting bead assay provides a miniaturized, solvent-free exposure system. Potential future applications include the coupling to environmental sampling, in which the bead material is used as solid receiving phase before serving as a surface for vertebrate cells to attach and respond. [source]

    Mobilization of pesticides on an agricultural landscape flooded by a torrential storm

    David B. Donald
    Abstract Mobilization of pesticides into surface waters of flooded agricultural landscapes following extreme precipitation events has not been previously investigated. After receiving 96 mm of rain in the previous 45 d, the Vanguard area of southeastern Saskatchewan, Canada, was subjected to a torrential storm on July 3, 2000, that produced as much as 375 mm of rain in 8 h. The majority of herbicides, but no insecticides, would have been applied to crops in the Vanguard area during the four weeks preceding the storm. After the storm, 19 herbicides and insecticides were detected in flooded wetlands, with 14 of them detected in 50% or more of wetlands. Average concentrations ranged from 0.43 ng/L (endosulfan) to 362 ng/L (2,4-dichlorophenoxyacedic acid). The pesticides probably were from long-range transport, followed by deposition in rain, and from herbicides applied to crops within the area subjected to the storm (1,700 km2). In the following year, when only 62 mm of rain fell in the same 45 d, only five pesticides were detected in 50% or more of wetlands. We estimated that for the 1,700-km2 storm zone, 278 kg of herbicide were mobilized into rain and by runoff into surface waters, and 105 kg were removed from the Vanguard area by discharge into Notukeu Creek. Significant quantities of herbicides are mobilized to aquatic environments when prairie agricultural landscapes are subjected to torrential storms. In these circumstances, flooded wells and small municipal reservoirs used as sources of drinking water may be compromised by 10 or more pesticides, some at relatively high concentrations. [source]

    Unnatural landscapes in ecology: generating the spatial distribution of brine spills,

    ENVIRONMETRICS, Issue 7 2005
    Henriette I. Jager
    Abstract Quantitative tools are needed to evaluate the ecological effects of increasing petroleum production. In this article, we describe two stochastic models for simulating the spatial distribution of brine spills on a landscape. One model uses general assumptions about the spatial arrangement of spills and their sizes; the second model distributes spills by siting rectangular well complexes and conditioning spill probabilities on the configuration of pipes. We present maps of landscapes with spills produced by the two methods and compare the ability of the models to reproduce a specified spill area. A strength of the models presented here is their ability to extrapolate from the existing landscape to simulate landscapes with a higher (or lower) density of oil wells. Published in 2005 by John Wiley & Sons, Ltd. [source]

    Using spatial models and kriging techniques to optimize long-term ground-water monitoring networks: a case study

    ENVIRONMETRICS, Issue 5-6 2002
    Kirk Cameron
    Abstract In a pilot project, a spatial and temporal algorithm (geostatistical temporal,spatial or GTS) was developed for optimizing long-term monitoring (LTM) networks. Data from two monitored ground-water plumes were used to test the algorithm. The primary objective was to determine the degree to which sampling, laboratory analysis, and/or well construction resources could be pared without losing key statistical information concerning the plumes. Optimization of an LTM network requires an accurate assessment of both ground-water quality over time and trends or other changes in individual monitoring wells. Changes in interpolated concentration maps over time indicate whether ground-water quality has improved or declined. GTS separately identifies temporal and spatial redundancies. Temporal redundancy may be reduced by lengthening the time between sample collection. Spatial redundancy may be reduced by removing wells from the network which do not significantly impact assessment of ground-water quality. Part of the temporal algorithm in GTS involves computation of a composite temporal variogram to determine the least redundant overall sampling interval. Under this measure of autocorrelation between sampling events, the lag time at which the variogram reaches a sill is the sampling interval at which same-well measurements lack correlation and are therefore non-redundant. The spatial algorithm assumes that well locations are redundant if nearby wells offer nearly the same statistical information about the underlying plume. A well was considered redundant if its removal did not significantly change: (i) an interpolated map of the plume; (ii) the local kriging variances in that section of the plume; and (iii) the average global kriging variance. To identify well redundancy, local kriging weights were accumulated into global weights and used to gauge each well's relative contribution to the interpolated plume map. By temporarily removing that subset of wells with the lowest global kriging weights and re-mapping the plume, it was possible to determine how many wells could be removed without losing critical information. Test results from the Massachusetts Military Reserve (MMR) indicated that substantial savings in sampling, analysis and operational costs could be realized by utilizing GTS. Annual budgetary savings that would accrue were estimated at between 35 per cent and 5 per cent for both LTM networks under study.Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Disruption of self-organized actions in monkeys with progressive MPTP-induced parkinsonism: II.

    Effects of reward preference
    Abstract The motor and cognitive symptoms of Parkinson's disease (PD) are well documented, but little is known about the functionality of motivational processes mediated by the limbic circuits of basal ganglia. The aim of this study was to test the ability of motivational processes to direct and to urge behaviour, in four vervet monkeys (Cercopithecus aethiops) progressively intoxicated with systemic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injections (0.3,0.4 mg/kg every 4,7 days). In the food preference task, the monkeys had to retrieve two types of directly visible food, simultaneously available in the wells of a reward board. At all stages of MPTP-induced parkinsonism, the monkeys continued to take their favourite food first. In the symbol discrimination task, the wells were covered with sliding plaques cued by symbols indicating the absence or presence of a reward, and the different types of food were blocked in separate sessions. Monkeys with mild or moderate parkinsonism made fewer attempts and took longer to retrieve non-preferred compared with preferred rewards. These results indicate that motivational processes are still able to direct (food preference task) and to urge (symbol discrimination task) behaviour in MPTP-lesioned monkeys. Such a functional preservation may be related to the relatively spared dopaminergic innervation of the limbic circuits that we found in our monkeys, in agreement with the literature on humans. Furthermore, the frequency of executive disorders (such as hesitations and freezing) appeared to be much lower with the preferred rewards. Thus, the preserved motivational processes may help to overcome executive dysfunction in the early stages of human PD. [source]

    Exploration of the functional hierarchy of the basal layer of human epidermis at the single-cell level using parallel clonal microcultures of keratinocytes

    Nicolas O. Fortunel
    Please cite this paper as: Exploration of the functional hierarchy of the basal layer of human epidermis at the single-cell level using parallel clonal microcultures of keratinocytes. Experimental Dermatology 2010. Abstract:, The basal layer of human epidermis contains both stem cells and keratinocyte progenitors. Because of this cellular heterogeneity, the development of methods suitable for investigations at a clonal level is dramatically needed. Here, we describe a new method that allows multi-parallel clonal cultures of basal keratinocytes. Immediately after extraction from tissue samples, cells are sorted by flow cytometry based on their high integrin-,6 expression and plated individually in microculture wells. This automated cell deposition process enables large-scale characterization of primary clonogenic capacities. The resulting clonal growth profile provided a precise assessment of basal keratinocyte hierarchy, as the size distribution of 14-day-old clones ranged from abortive to highly proliferative clones containing 1.7 × 105 keratinocytes (17.4 cell doublings). Importantly, these 14-day-old primary clones could be used to generate three-dimensional reconstructed epidermis with the progeny of a single cell. In long-term cultures, a fraction of highly proliferative clones could sustain extensive expansion of >100 population doublings over 14 weeks and exhibited long-term epidermis reconstruction potency, thus fulfilling candidate stem cell functional criteria. In summary, parallel clonal microcultures provide a relevant model for single-cell studies on interfollicular keratinocytes, which could be also used in other epithelial models, including hair follicle and cornea. The data obtained using this system support the hierarchical model of basal keratinocyte organization in human interfollicular epidermis. [source]

    Staphylococcus aureus biofilm formation and tolerance to antibiotics in response to oscillatory shear stresses of physiological levels

    Victoria Kostenko
    Abstract Bacterial infections in the blood system are usually associated with blood flow oscillation generated by some cardiovascular pathologies and insertion of indwelling devices. The influence of hydrodynamically induced shear stress fluctuations on the Staphylococcus aureus biofilm morphology and tolerance to antibiotics was investigated. Fluctuating shear stresses of physiologically relevant levels were generated in wells of a six-well microdish agitated by an orbital shaker. Numerical simulations were performed to determine the spatial distribution and local fluctuation levels of the shear stress field on the well bottom. It is found that the local biofilm deposition and morphology correlate strongly with shear stress fluctuations and maximum magnitude levels. Tolerance to killing by antibiotics correlates with morphotype and is generally higher in high shear regions. [source]

    Bacterial community analysis of shallow groundwater undergoing sequential anaerobic and aerobic chloroethene biotransformation

    Todd R. Miller
    Abstract At Department of Energy Site 300, beneficial hydrocarbon cocontaminants and favorable subsurface conditions facilitate sequential reductive dechlorination of trichloroethene (TCE) and rapid oxidation of the resultant cis- dichloroethene (cis -DCE) upon periodic oxygen influx. We assessed the geochemistry and microbial community of groundwater from across the site. Removal of cis -DCE was shown to coincide with oxygen influx in hydrocarbon-containing groundwater near the source area. Principal component analysis of contaminants and inorganic compounds showed that monitoring wells could be differentiated based upon concentrations of TCE, cis -DCE, and nitrate. Structurally similar communities were detected in groundwater from wells containing cis -DCE, high TCE, and low nitrate levels. Bacteria identified by sequencing 16S rRNA genes belonged to seven phylogenetic groups, including Alpha -, Beta -, Gamma - and Deltaproteobacteria, Nitrospira, Firmicutes and Cytophaga,Flexibacter,Bacteroidetes (CFB). Whereas members of the Burkholderiales and CFB group were abundant in all wells (104,109 16S rRNA gene copies L,1), quantitative PCR showed that Alphaproteobacteria were elevated (>106 L,1) only in wells containing hydrocarbon cocontaminants. The study shows that bacterial community structure is related to groundwater geochemistry and that Alphaproteobacteria are enriched in locales where cis -DCE removal occurs. [source]

    Survival of Escherichia coli O157:H7 in private drinking water wells: influences of protozoan grazing and elevated copper concentrations

    Rebekka R.E Artz
    Abstract The survival characteristics of Escherichia coli O157:H7 in private drinking water wells were investigated to assess the potential for human exposure. A non-toxigenic, chromosomally lux -marked strain of E. coli O157:H7 was inoculated into well water from four different sites in the North East of Scotland. These waters differed significantly in their heavy metal contents as well as nutrient and bacterial grazer concentrations. Grazing and other biological factors were studied using filtered (3 and 0.2 ,m) and autoclaved water. The survival of E. coli O157:H7 was primarily decreased by elevated copper concentrations. This hypothesis was supported by acute toxicity assay data. In addition, significant protozoan predation effects were observed in untreated water when compared with survival rates in filtered water. The combination of these two factors in particular determines the survival time of the pathogen in a private water well. It therefore appears that wells with higher water quality as assessed using the European Union Drinking Water Directive standards will also allow survival of E. coli O157:H7 for much longer periods. [source]

    Porins of Pseudomonas fluorescens MFO as fibronectin-binding proteins

    J. Rebière-Huët
    Abstract Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3). [source]