75 research outputs found

    Offensive Motivation Strategies: The Managerial And Legal Implications

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    This case study focuses on corporate culture, ethics, employment law, and motivation theory and is appropriate for use in a variety of management classes, such as organizational behavior, human resource management, or ethics.  It profiles a lawsuit brought against a company by one of its female employees who was subjected to a variety of “camaraderie building” exercises, including being spanked with a competitor’s metal poled yard sign.  The case is based on a true story.  Only the names and locations have been changed.  This case includes actual descriptions of company practices and communications which are offensive and may be disturbing.  However, they have been included so that the reader can appreciate the severity of the “motivational practices” that were being employed. &nbsp

    Neonicotinoid seed treatment products – Occurrence and relevance of guttation for honeybee colonies

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    Background: Guttation is a natural botanical phenomenon and describes the active excretion of liquid water (guttation fluid) by some vascular plants in form of droplets on the tips of leaves or on leaf edges. Guttation fluid may contain neonicotinoid residues after plant uptake from seed treatments. To clarify the relevance of the guttation fluid as a water source for honey bee colonies and to assess potential associated risks under conditions of agronomic practice, various studies were performed in key broad acre crops such as maize, sugar beet, potato (in-furrow application), winter barley and oilseed rape by placing honeybee colonies adjacent to freshly emerged fields for several weeks and by following up potential lethal and sub-lethal effects, as well as potential effects on colony performance.Results: Guttation droplets contained peak residue levels theoretically capable of harming individual honeybees (i.e. several hundred ppm). Residue levels, however, generally decreased with time, as expected based on the physiological process involved. The temporal coincidence of honeybee flight activity and the presence of guttation droplets were generally limited to early morning hours and to a much lesser extent to evening hours. Spatially, honeybees were found to predominately collect water, if any, in the direct vicinity of the hives. Water collection generally ceased within a couple of metres distance to the hives, which renders distance to the crop to be a significant exposure factor, and in turn renders dew and guttation from off-crop vegetation to be more relevant to water collecting honeybees than guttation from the crop. Mortality events, if any, were scarce and generally matched in treatments and in controls. The absolute numbers of dead bees involved in these rare cases were so low that they did not translate into any colony level effects or impacts on bee health or overwintering success, nor on adverse effects on honey production of the involved colonies.Conclusions: Given the overall body of data, the associated intensity of the assessments in each study as well as the worst-case exposure conditions employed, it can be concluded that exposure of honeybee colonies to guttation fluid, excreted from neonicotinoid seed-treated crop plants, did not pose an unacceptable acute or chronic risk to honeybee colony development or survival, and does not adversely interfere with bee keeping practices. Overall, guttation water from seedtreated crop plants was found not to be a significant exposure route for honeybees.Keywords: pesticide, honey bee, guttatio

    Pulsed Electric Field Ablation of Esophageal Malignancies and Mitigating Damage to Smooth Muscle: An In Vitro Study

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    Cancer ablation therapies aim to be efficient while minimizing damage to healthy tissues. Nanosecond pulsed electric field (nsPEF) is a promising ablation modality because of its selectivity against certain cell types and reduced neuromuscular effects. We compared cell killing efficiency by PEF (100 pulses, 200 ns–10 µs duration, 10 Hz) in a panel of human esophageal cells (normal and pre-malignant epithelial and smooth muscle). Normal epithelial cells were less sensitive than the pre-malignant ones to unipolar PEF (15–20% higher LD50, p \u3c 0.05). Smooth muscle cells (SMC) oriented randomly in the electric field were more sensitive, with 30–40% lower LD50 (p \u3c 0.01). Trains of ten, 300-ns pulses at 10 kV/cm caused twofold weaker electroporative uptake of YO-PRO-1 dye in normal epithelial cells than in either pre-malignant cells or in SMC oriented perpendicularly to the field. Aligning SMC with the field reduced the dye uptake fourfold, along with a twofold reduction in Ca2+ transients. A 300-ns pulse induced a twofold smaller transmembrane potential in cells aligned with the field, making them less vulnerable to electroporation. We infer that damage to SMC from nsPEF ablation of esophageal malignancies can be minimized by applying the electric field parallel to the predominant SMC orientation

    Control of the Electroporation Efficiency of Nanosecond Pulses by Swinging the Electric Field Vector Direction

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    Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as “bipolar cancellation,” enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing the electric field in the pairs (180° direction change) caused 2-fold (1 Hz) or 20-fold (833 kHz) weaker electroporation than the train of single nsEPs. Reducing the angle between pulse directions in the pairs weakened cancellation and replaced it with facilitation at angles \u3c160° (1 Hz) and \u3c130° (833 kHz). Facilitation plateaued at about three-fold stronger electroporation compared to single pulses at 90–100° angle for both nsEP frequencies. The profound dependence of the efficiency on the angle enables novel protocols for highly selective focal electroporation at one electrode in a three-electrode array while avoiding effects at the other electrodes. Nanosecond-resolution imaging of cell membrane potential was used to link the selectivity to charging kinetics by co- and counter-directional nsEPs

    Human cyclin T1 expression ameliorates a T-cell-specific transcriptional limitation for HIV in transgenic rats, but is not sufficient for a spreading infection of prototypic R5 HIV-1 strains ex vivo

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    <p>Abstract</p> <p>Background</p> <p>Cells derived from native rodents have limits at distinct steps of HIV replication. Rat primary CD4 T-cells, but not macrophages, display a profound transcriptional deficit that is ameliorated by transient trans-complementation with the human Tat-interacting protein Cyclin T1 (hCycT1).</p> <p>Results</p> <p>Here, we generated transgenic rats that selectively express hCycT1 in CD4 T-cells and macrophages. hCycT1 expression in rat T-cells boosted early HIV gene expression to levels approaching those in infected primary human T-cells. hCycT1 expression was necessary, but not sufficient, to enhance HIV transcription in T-cells from individual transgenic animals, indicating that endogenous cellular factors are critical co-regulators of HIV gene expression in rats. T-cells from hCD4/hCCR5/hCycT1-transgenic rats did not support productive infection of prototypic wild-type R5 HIV-1 strains <it>ex vivo</it>, suggesting one or more significant limitation in the late phase of the replication cycle in this primary rodent cell type. Remarkably, we identify a replication-competent HIV-1 GFP reporter strain (R7/3 YU-2 Env) that displays characteristics of a spreading, primarily cell-to-cell-mediated infection in primary T-cells from hCD4/hCCR5-transgenic rats. Moreover, the replication of this recombinant HIV-1 strain was significantly enhanced by hCycT1 transgenesis. The viral determinants of this so far unique replicative ability are currently unknown.</p> <p>Conclusion</p> <p>Thus, hCycT1 expression is beneficial to <it>de novo </it>HIV infection in a transgenic rat model, but additional genetic manipulations of the host or virus are required to achieve full permissivity.</p

    Progress Toward a Human CD4/CCR5 Transgenic Rat Model for De Novo Infection by Human Immunodeficiency Virus Type 1

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    The development of a permissive small animal model for the study of human immunodeficiency virus type (HIV)-1 pathogenesis and the testing of antiviral strategies has been hampered by the inability of HIV-1 to infect primary rodent cells productively. In this study, we explored transgenic rats expressing the HIV-1 receptor complex as a susceptible host. Rats transgenic for human CD4 (hCD4) and the human chemokine receptor CCR5 (hCCR5) were generated that express the transgenes in CD4+ T lymphocytes, macrophages, and microglia. In ex vivo cultures, CD4+ T lymphocytes, macrophages, and microglia from hCD4/hCCR5 transgenic rats were highly susceptible to infection by HIV-1 R5 viruses leading to expression of abundant levels of early HIV-1 gene products comparable to those found in human reference cultures. Primary rat macrophages and microglia, but not lymphocytes, from double-transgenic rats could be productively infected by various recombinant and primary R5 strains of HIV-1. Moreover, after systemic challenge with HIV-1, lymphatic organs from hCD4/hCCR5 transgenic rats contained episomal 2–long terminal repeat (LTR) circles, integrated provirus, and early viral gene products, demonstrating susceptibility to HIV-1 in vivo. Transgenic rats also displayed a low-level plasma viremia early in infection. Thus, transgenic rats expressing the appropriate human receptor complex are promising candidates for a small animal model of HIV-1 infection

    Novel Peptide Sequence (“IQ-tag”) with High Affinity for NIR Fluorochromes Allows Protein and Cell Specific Labeling for In Vivo Imaging

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    Probes that allow site-specific protein labeling have become critical tools for visualizing biological processes.Here we used phage display to identify a novel peptide sequence with nanomolar affinity for near infrared (NIR) (benz)indolium fluorochromes. The developed peptide sequence ("IQ-tag") allows detection of NIR dyes in a wide range of assays including ELISA, flow cytometry, high throughput screens, microscopy, and optical in vivo imaging.The described method is expected to have broad utility in numerous applications, namely site-specific protein imaging, target identification, cell tracking, and drug development

    An optimised assay for quantitative, high-throughput analysis of polysialyltransferase activity

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    YesThe polysialyltransferases are biologically important glycosyltransferase enzymes responsible for the biosynthesis of polysialic acid, a carbohydrate polymer that plays a critical role in the progression of several diseases, notably cancer. Having improved the chemical synthesis and purification of the fluorescently-labelled DMB-DP3 acceptor, we report optimisation and validation of a highly sensitive cell-free high-throughput HPLC-based assay for assessment of human polysialyltransferase activity
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