5,883 research outputs found

    Surgical injury in the neonatal rat alters the adult pattern of descending modulation from the rostroventral medulla

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    Background: Neonatal pain and injury can alter long-term sensory thresholds. Descending rostroventral medulla (RVM) pathways can inhibit or facilitate spinal nociceptive processing in adulthood. As these pathways undergo significant postnatal maturation, the authors evaluated long-term effects of neonatal surgical injury on RVM descending modulation. Methods: Plantar hind paw or forepaw incisions were performed in anesthetized postnatal day (P)3 Sprague-Dawley rats. Controls received anesthesia only. Hind limb mechanical and thermal withdrawal thresholds were measured to 6 weeks of age (adult). Additional groups received pre- and post-incision sciatic nerve levobupivacaine or saline. Hind paw nociceptive reflex sensitivity was quantified in anesthetized adult rats using biceps femoris electromyography, and the effect of RVM electrical stimulation (5–200 μA) measured as percentage change from baseline. Results: In adult rats with previous neonatal incision (n = 9), all intensities of RVM stimulation decreased hind limb reflex sensitivity, in contrast to the typical bimodal pattern of facilitation and inhibition with increasing RVM stimulus intensity in controls (n = 5) (uninjured vs. neonatally incised, P < 0.001). Neonatal incision of the contralateral hind paw or forepaw also resulted in RVM inhibition of hind paw nociceptive reflexes at all stimulation intensities. Behavioral mechanical threshold (mean ± SEM, 28.1 ± 8 vs. 21.3 ± 1.2 g, P < 0.001) and thermal latency (7.1 ± 0.4 vs. 5.3 ± 0.3 s, P < 0.05) were increased in both hind paws after unilateral neonatal incision. Neonatal perioperative sciatic nerve blockade prevented injury-induced alterations in RVM descending control. Conclusions: Neonatal surgical injury alters the postnatal development of RVM descending control, resulting in a predominance of descending inhibition and generalized reduction in baseline reflex sensitivity. Prevention by local anesthetic blockade highlights the importance of neonatal perioperative analgesia

    van der Waals epitaxy of monolayer hexagonal boron nitride on copper foil : growth, crystallography and electronic band structure

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    We investigate the growth of hexagonal boron nitride (h-BN) on copper foil by low pressure chemical vapour deposition (LP-CVD). At low pressure, h-BN growth proceeds through the nucleation and growth of triangular islands. Comparison between the orientation of the islands and the local crystallographic orientation of the polycrystalline copper foil reveals an epitaxial relation between the copper and h-BN, even on Cu(100) and Cu(110) regions whose symmetry is not matched to the h-BN. However, the growth rate is faster and the islands more uniformly oriented on Cu(111) grains. Angle resolved photoemission spectroscopy measurements reveal a well-defined band structure for the h-BN, consistent with a band gap of 6 eV, that is decoupled from the copper surface beneath. These results indicate that, despite a weak interaction between h-BN and copper, van der Waals epitaxy defines the long range ordering of h-BN even on polycrystalline copper foils and suggest that large area, single crystal, monolayer h-BN could be readily and cheaply produced

    Synthesis and Luminescence Modulation of Pyrazine-Based Gold(III) Pincer Complexes

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    The first examples of pyrazine-based gold(III) pincer complexes have been synthesized; their intense photoemissions can be modified by interactions with the non-coordinating pyrazine-N atom. Luminescence modulation is possible without the need for altering the ligand framework. Emissions shift from red (77 K) to blue (298 K) due to thermally activated delayed fluorescence (TADF

    The macrofilaricidal efficacy of repeated doses of ivermectin for the treatment of river blindness

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    Background: Mass drug administration (MDA) with ivermectin is the cornerstone of efforts to eliminate human onchocerciasis by 2020 or 2025. The feasibility of elimination crucially depends on the effects of multiple ivermectin doses on Onchocerca volvulus. A single ivermectin (standard) dose clears the skin-dwelling microfilarial progeny of adult worms (macrofilariae) and temporarily impedes the release of such progeny by female macrofilariae, but a macrofilaricidal effect has been deemed minimal. Multiple doses of ivermectin may cumulatively and permanently reduce the fertility and shorten the lifespan of adult females. However, rigorous quantification of these effects necessitates interrogating longitudinal data on macrofilariae with suitably powerful analytical techniques. Methods: Using a novel mathematical modeling approach, we analyzed, at an individual participant level, longitudinal data on viability and fertility of female worms from the single most comprehensive multiple-dose clinical trial of ivermectin, comparing 3-monthly with annual treatments administered for 3 years in Cameroon

    Understanding Implementation Strategies to Support Classroom-Based Physical activity approaches in Elementary Schools: a Qualitative Study

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    BACKGROUND: Classroom-based physical activity approaches can improve children\u27s physical activity levels during school. However, the implementation of these approaches remains a challenge. The purpose of this study was to examine implementation strategies to support the delivery of classroom-based physical activity approaches from the perspectives of elementary school staff. METHODS: We conducted individual interviews with elementary school staff from a mid-sized school district in Texas. Interviews lasted approximately 60 min and were audio recorded and transcribed for analyses. We used directed content analysis and an iterative categorization approach to identify emerging themes related to implementation strategies. RESULTS: We interviewed 15 participants (4 classroom teachers, 4 physical education teachers, 3 assistant principals, and 4 principals) about implementation strategies supporting classroom-based physical activity approaches. Four prominent themes related to implementation strategies emerged: 1) the role of program champions, 2) the use and function of staff training, 3) the importance of strategic planning, and 4) the use of positive reinforcements to support implementation. CONCLUSIONS: Results highlight the need for multiple implementation strategies to support the delivery of classroom-based physical activity approaches. Results also highlight potential mechanisms through which the implementation strategies operate. This information is valuable to future planning efforts for classroom-based physical activity approaches

    Early-life adversity programs long-term cytokine and microglia expression within the HPA axis in female Japanese quail

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    This work was funded by the Biotechnology and Biological Sciences Research Council (BBSRC grant no. BB/L002264/1 to K.A.S., C.Z. and S.D.H.), a David Phillips Research Fellowship (K.A.S.) and an EASTBIO BBSRC Doctoral Training Programme studentship (grant no. BB/J01446X/1 to D.J.W., supervisors K.A.S., S.D.H.). Data are available from Mendeley (Walker, 2019): http://dx.doi.org/10.17632/ 6r7d2pg2zk.1Stress exposure during prenatal and postnatal development can have persistent and often dysfunctional effects on several physiological systems, including immune function, affecting the ability to combat infection. The neuroimmune response is inextricably linked to the action of the hypothalamic–pituitary–adrenal (HPA) axis. Cytokines released from neuroimmune cells, including microglia, activate the HPA axis, while glucocorticoids in turn regulate cytokine release from microglia. Because of the close links between these two physiological systems, coupled with potential for persistent changes to HPA axis activity following developmental stress, components of the neuroimmune system could be targets for developmental programming. However, little is known of any programming effects of developmental stress on neuroimmune function. We investigated whether developmental stress exposure via elevated prenatal corticosterone (CORT) or postnatal unpredictable food availability had long-term effects on pro- (IL-1β) and anti-inflammatory (IL-10) cytokine and microglia-dependent gene (CSF1R) expression within HPA axis tissues in a precocial bird, the Japanese quail (Coturnix japonica). Following postnatal stress, we observed increased IL-1β expression in the pituitary gland, reduced IL-10 expression in the amygdala and hypothalamus, and reduced CSF1R expression within the hypothalamus and pituitary gland. Postnatal stress disrupted the ratio of IL-1β:IL-10 expression within the hippocampus and hypothalamus. Prenatal stress only increased IL-1β expression in the pituitary gland. We found no evidence for interactive or cumulative effects across life stages on basal cytokine and glia expression in adulthood. We show that postnatal stress may have a larger impact than elevated prenatal CORT on basal immunity in HPA-axis-specific brain regions, with changes in cytokine homeostasis and microglia abundance. These results provide evidence for postnatal programming of a pro-inflammatory neuroimmune phenotype at the expense of reduced microglia, which could have implications for central nervous system health and subsequent neuroimmune responses.Publisher PDFPeer reviewe

    Evidence-Based intervention (Ebi) Mapping: a Systematic approach to Understanding the Components and Logic of Ebis

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    BACKGROUND: Despite the development of numerous evidence-based interventions (EBIs), many go unused in practice. Hesitations to use existing EBIs may be due to a lack of understanding about EBI components and what it would take to adapt it or implement it as designed. to improve the use of EBIs, program planners need to understand their goals, core components, and mechanisms of action. This paper presents EBI Mapping, a systematic approach based on Intervention Mapping, that can be used to understand and clearly describe EBIs, and help planners put them into practice. METHODS: We describe EBI Mapping tasks and provide an example of the process. EBI Mapping uses principles from Intervention Mapping, a systematic framework for planning multilevel health promotion interventions. EBI Mapping applies the Intervention Mapping steps retrospectively to help planners understand an existing EBI (rather than plan a new one). We explain each EBI Mapping task and demonstrate the process using the VERB Summer Scorecard (VSS), a multi-level community-based intervention to improve youth physical activity. RESULTS: EBI Mapping tasks are: 1) document EBI materials and activities, and their audiences, 2) identify the EBI goals, content, and mechanisms of action, 3) identify the theoretical change methods and practical applications of those methods, 4) describe design features and delivery channels, and 5) describe the implementers and their tasks, implementation strategies, and needed resources. By applying the EBI Mapping tasks, we created a logic model for the VSS intervention. The VSS logic model specifies the links between behavior change methods, practical applications, and determinants for both the at-risk population and environmental change agents. The logic model also links the respective determinants to the desired outcomes including the health behavior and environmental conditions to improve the health outcome in the at-risk population. CONCLUSIONS: EBI Mapping helps program planners understand the components and logic of an EBI. This information is important for selecting, adapting, and scaling-up EBIs. Accelerating and improving the use of existing EBIs can reduce the research-to-practice gap and improve population health

    High Avidity CD8+ T Cells Efficiently Eliminate Motile HIV-Infected Targets and Execute a Locally Focused Program of Anti-Viral Function

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    The dissemination of HIV from an initial site of infection is facilitated by motile HIV-infected CD4+ T-cells. However, the impact of infected target cell migration on antigen recognition by HIV-specific CD8+ T-cells is unclear. Using a 3D in vitro model of tissue, we visualized dynamic interactions between HIV-infected or peptide-pulsed CD4+ T-cells and HIV-specific CD8+ T-cells. CTLs engaged motile HIV-infected targets, but ∼50% of targets broke contact and escaped. In contrast, immobilized target cells were readily killed, indicating target motility directly inhibits CD8+ T-cell function. Strong calcium signals occurred in CTLs killing a motile target but calcium signaling was weak or absent in CTLs which permitted target escape. Neutralization of adhesion receptors LFA-1 and CD58 inhibited CD8+ T-cell function within the 3D matrix, demonstrating that efficient motile target lysis as dependent on adhesive engagement of targets. Antigen sensitivity (a convolution of antigen density, TCR avidity and CD8 coreceptor binding) is also critical for target recognition. We modulated this parameter (known as functional avidity but referred to here as “avidity” for the sake of simplicity) by exploiting common HIV escape mutations and measured their impact on CTL function at the single-cell level. Targets pulsed with low avidity mutant antigens frequently escaped while CTLs killed targets bearing high avidity antigen with near-perfect efficiency. CTLs engaged, arrested, and killed an initial target bearing high avidity antigen within minutes, but serial killing was surprisingly rare. CD8 cells remained committed to their initial dead target for hours, accumulating TCR signals that sustained secretion of soluble antiviral factors. These data indicate that high-avidity CD8+ T-cells execute an antiviral program in the precise location where antigen has been sensed: CTL effector functions are spatiotemporally coordinated with an early lytic phase followed by a sustained stationary secretory phase to control local viral infection

    Automated Analysis of MUTEX Algorithms with FASE

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    In this paper we study the liveness of several MUTEX solutions by representing them as processes in PAFAS s, a CCS-like process algebra with a specific operator for modelling non-blocking reading behaviours. Verification is carried out using the tool FASE, exploiting a correspondence between violations of the liveness property and a special kind of cycles (called catastrophic cycles) in some transition system. We also compare our approach with others in the literature. The aim of this paper is twofold: on the one hand, we want to demonstrate the applicability of FASE to some concrete, meaningful examples; on the other hand, we want to study the impact of introducing non-blocking behaviours in modelling concurrent systems.Comment: In Proceedings GandALF 2011, arXiv:1106.081

    How can onchocerciasis elimination in Africa be accelerated? Modelling the impact of increased ivermectin treatment frequency and complementary vector control

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    Background: Great strides have been made toward onchocerciasis elimination by mass drug administration (MDA) of ivermectin. Focusing on MDA-eligible areas, we investigated where the elimination goal can be achieved by 2025 by continuation of current practice (annual MDA with ivermectin) and where intensification or additional vector control is required. We did not consider areas hypoendemic for onchocerciasis with loiasis coendemicity where MDA is contraindicated. Methods: We used 2 previously published mathematical models, ONCHOSIM and EPIONCHO, to simulate future trends in microfilarial prevalence for 80 different settings (defined by precontrol endemicity and past MDA frequency and coverage) under different future treatment scenarios (annual, biannual, or quarterly MDA with different treatment coverage through 2025, with or without vector control strategies), assessing for each strategy whether it eventually leads to elimination. Results: Areas with 40%–50% precontrol microfilarial prevalence and ≥10 years of annual MDA may achieve elimination with a further 7 years of annual MDA, if not achieved already, according to both models. For most areas with 70%–80% precontrol prevalence, ONCHOSIM predicts that either annual or biannual MDA is sufficient to achieve elimination by 2025, whereas EPIONCHO predicts that elimination will not be achieved even with complementary vector control. Conclusions: Whether elimination will be reached by 2025 depends on precontrol endemicity, control history, and strategies chosen from now until 2025. Biannual or quarterly MDA will accelerate progress toward elimination but cannot guarantee it by 2025 in high-endemicity areas. Long-term concomitant MDA and vector control for high-endemicity areas might be useful
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