Publications by authors named "Lafleur C"

The SPARC tokamak is a high-field, Bt0 ∼12 T, medium-sized, R0 = 1.85 m, tokamak that is presently under construction in Devens, MA, led by Commonwealth Fusion Systems. It will be used to de-risk the high-field tokamak path to a fusion power plant and demonstrate the commercial viability of fusion energy.

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A suite of plasma diagnostics will be installed on the SPARC tokamak to allow for real-time plasma control, an investigation of high-field tokamak physics, and to de-risk the design of ARC, a compact fusion power plant with the aim to supply electricity to the grid. Among these diagnostics is the neutral gas diagnostics system (NTGS), a set of pressure sensors and gas analyzers used to monitor neutral pressure and gas composition for plasma control, optimization of wall conditioning, and helium ash removal, among other measurement functions linked to operational and scientific research needs. While reliable measurements of neutral pressure and gas composition have been fielded on existing magnetic-confinement fusion devices, SPARC represents a step increase in challenge due to its larger power density, higher field, high vacuum vessel bake temperatures, and higher neutron flux environment, as well as a step decrease in the accessibility for maintenance of in-vessel sensors.

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Article Synopsis
  • The SPARC tokamak is a fusion reactor that will get very hot, so it's important to manage the heat to keep everything safe.
  • To do this, they will use special tools called thermal diagnostics to measure the temperatures inside the reactor and make sure they don't get too high.
  • Different types of sensors will be used, and they are designed to survive extreme conditions, including super high temperatures and radiation, since fixing them later will be really hard.
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To control and optimize the power of the SPARC tokamak, we require information on the total radiated power of the plasma and its 2D and 3D spatial distribution. The SPARC bolometry diagnostic is being designed and built to measure the radiated power for controlling power balance, investigating the dissipation capabilities of various divertor concepts, and measuring the efficacy of the disruption thermal load mitigation. Proven resistive bolometer sensor technology will be used, with 248 lines of sight integrated into pinhole cameras in 20 different locations.

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In wounded leaves, four 13-lipoxygenases (AtLOX2, AtLOX3, AtLOX4, AtLOX6) act in a hierarchical manner to contribute to the jasmonate burst. This leads to defense responses with LOX2 playing an important role in plant resistance against caterpillar herb-ivory. In this study, we sought to characterize the impact of AtLOX2 on wound-induced phytohormonal and transcriptional responses to foliar mechanical damage using wildtype (WT) and mutant plants.

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Many plant species, particularly legumes, protect themselves with saponins. Previously, a correlation was observed between levels of oleanolic acid-derived saponins, such as hederagenin-derived compounds, in the legume Medicago truncatula and caterpillar deterrence. Using concentrations that reflect the foliar levels of hederagenin-type saponins, the sapogenin hederagenin was not toxic to 4th instar caterpillars of the cabbage looper Trichoplusia ni nor did it act as a feeding deterrent.

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Background: Integrated Pest Management (IPM) seeks to combine multiple management strategies for optimal pest control. One method that is successfully employed in IPM is the use of beneficial organisms. However, in severe circumstances when pest insects exceed threshold limits, insecticides may still need to be implemented.

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Background: The organochlorine dichlorodiphenyltrichloroethane (DDT) is banned worldwide owing to its negative health effects. It is exceptionally used as an insecticide for malaria control. Exposure occurs in regions where DDT is applied, as well as in the Arctic, where its endocrine disrupting metabolite, dichlorodiphenyldichloroethylene (DDE) accumulates in marine mammals and fish.

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Coronavirus disease (COVID-19) has had a significant impact on global health since the start of the pandemic in 2019. As of June 2022, over 539 million cases have been confirmed worldwide with over 6.3 million deaths as a result.

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Objective: Parental environmental exposures can strongly influence descendant risks for adult disease. How paternal obesity changes the sperm chromatin leading to the acquisition of metabolic disease in offspring remains controversial and ill-defined. The objective of this study was to assess (1) whether obesity induced by a high-fat diet alters sperm histone methylation; (2) whether paternal obesity can induce metabolic disturbances across generations; (3) whether there could be cumulative damage to the sperm epigenome leading to enhanced metabolic dysfunction in descendants; and (4) whether obesity-sensitive regions associate with embryonic epigenetic and transcriptomic profiles.

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In the field of epigenetic inheritance, delineating molecular mechanisms implicated in the transfer of paternal environmental conditions to descendants has been elusive. This protocol details how to track sperm chromatin intergenerationally. We describe mouse model design to probe chromatin states in single mouse sperm and techniques to assess pre-implantation embryo chromatin and gene expression.

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A father's lifestyle impacts offspring health; yet, the underlying molecular mechanisms remain elusive. We hypothesized that a diet that changes methyl donor availability will alter the sperm and embryo epigenomes to impact embryonic gene expression and development. Here, we demonstrate that a folate-deficient (FD) diet alters histone H3 lysine 4 trimethylation (H3K4me3) in sperm at developmental genes and putative enhancers.

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Advancing the molecular knowledge surrounding fertility and inheritance has become critical given the halving of sperm counts in the last 40 years, and the rise in complex disease which cannot be explained by genetics alone. The connection between both these trends may lie in alterations to the sperm epigenome and occur through environmental exposures. Changes to the sperm epigenome are also associated with health risks across generations such as metabolic disorders and cancer.

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Hibernators suppress physiological processes when expressing torpor, yet little is known about the effects of torpor on male reproductive physiology. Studies of hibernating mammals suggest that deep torpor negatively impacts spermatogenesis and that transitions between torpor and euthermic arousals increase cellular oxidative stress, with potentially damaging effects on sperm. Here, we hypothesize that variation in torpor expression affects the reproductive readiness of hibernators by impacting their sperm production.

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Cybersecurity stands to benefit greatly from models able to generate predictions of attacker and defender behavior. On the defender side, there is promising research suggesting that Symbolic Deep Learning (SDL) may be employed to automatically construct cognitive models of expert behavior based on small samples of expert decisions. Such models could then be employed to provide decision support for non-expert users in the form of explainable expert-based suggestions.

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Background: Extracorporeal membrane oxygenation (ECMO) has frequent and sometimes lethal thrombotic complications. The role that activated platelets, leukocytes, and small (0.3-micron to 1-micron) extracellular vesicles (EVs) play in ECMO thrombosis is not well understood.

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Mobile health (mHealth) applications have been developed for community health workers (CHW) to help simplify tasks, enhance service delivery and promote healthy behaviours. These strategies hold promise, particularly for support of pregnancy and childbirth in low-income countries (LIC), but their design and implementation must incorporate CHW clients' perspectives to be effective and sustainable. Few studies examine how mHealth influences client and supervisor perceptions of CHW performance and quality of care in LIC.

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Background: Adolescents are especially vulnerable due to increased biological, social and economic risks associated with early pregnancy and childbirth, yet most pregnancy and childbirth-related complications are preventable through a combination of proven, cost-effective clinical interventions including timely antenatal care (ANC). The voices and specific needs of adolescents are currently underrepresented in the literature on antenatal and maternity care. Objectives were to a) increase our understanding of adolescents' experiences with, and perceptions of, ANC and b) explore how these perspectives might be applied towards future initiatives to enhance adolescent care-seeking behaviour.

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Environmental exposures can alter the long-term health and development of offspring. How this environmental information is transmitted via the germline remains unknown, but it is thought to involve epigenetic inheritance. We recently determined that genetic disruption of histone H3 di-methylation at lysine 4 (H3K4me2) in sperm alters gene expression in the embryo and negatively impacts development across generations.

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Background: About half of births in rural Tanzania are assisted by skilled providers. Point-of-care mobile phone applications hold promise in boosting job support for community health workers aiming to ensure safe motherhood through increased facility delivery awareness, access and uptake. We conducted a controlled comparison to evaluate a smartphone-based application designed to assist community health workers with data collection, education delivery, gestational danger sign identification, and referrals.

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Background: Refrigeration of platelets (PLTs) in a PLT additive solution (PAS) reduces PLT activation compared to storage in plasma and preserves function for at least 15 days. Currently only two PASs are licensed by the Food and Drug Administration, each for use with only one apheresis platform. In this study, we compared the metabolic, functional, and activation status of PLTs collected on a Trima apheresis collection system and stored refrigerated in Isoplate (ISO) PAS to PLTs collected on an Amicus collection system and stored refrigerated in Intersol (INT) PAS.

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A father's lifetime experiences can be transmitted to his offspring to affect health and development. However, the mechanisms underlying paternal epigenetic transmission are unclear. Unlike in somatic cells, there are few nucleosomes in sperm, and their function in epigenetic inheritance is unknown.

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Little is known of the fundamental processes governed by epigenetic mechanisms in the supplier cells of spermatogenesis, the spermatogonial stem cells (SSCs). The histone H3 lysine demethylase KDM1A is expressed in spermatogonia. We hypothesized that KDM1A serves in transcriptional regulation of SSCs and fertility.

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Impairments in pituitary FSH synthesis or action cause infertility. However, causes of FSH dysregulation are poorly described, in part because of our incomplete understanding of mechanisms controlling FSH synthesis. Previously, we discovered a critical role for forkhead protein L2 (FOXL2) in activin-stimulated FSH β-subunit (Fshb) transcription in immortalized cells in vitro.

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