2,786 research outputs found

    To Duckweeds (\u3cem\u3eLandoltia punctata\u3c/em\u3e), Nanoparticulate Copper Oxide is More Inhibitory than the Soluble Copper in the Bulk Solution

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    CuO nanoparticles (CuO-NP) were synthesized in a hydrogen diffusion flame. Particle size and morphology were characterized using scanning mobility particle sizing, Brunauer–Emmett–Teller analysis, dynamic light scattering, and transmission electron microscopy. The solubility of CuO-NP varied with both pH and presence of other ions. CuO-NP and comparable doses of soluble Cu were applied to duckweeds, Landoltia punctata. Growth was inhibited 50% by either 0.6 mg L−1 soluble copper or by 1.0 mg L−1 CuO-NP that released only 0.16 mg L−1 soluble Cu into growth medium. A significant decrease of chlorophyll was observed in plants stressed by 1.0 mg L−1 CuO-NP, but not in the comparable 0.2 mg L−1 soluble Cu treatment. The Cu content of fronds exposed to CuO-NP is four times higher than in fronds exposed to an equivalent dose of soluble copper, and this is enough to explain the inhibitory effects on growth and chlorophyll content

    Cal Poly Supermileage Vehicle Braking System

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    The Cal Poly Supermileage Vehicle (SMV) team has requested this team to design the braking systems for the 2021 Supermileage vehicle in accordance with the 2020 Shell Eco-marathon rules, weight restrictions, and team budget. A braking system consists of the front brake pedals, front pedal mount, cable management to the brake calipers, and the rear caliper mounts. This report outlines the concept design that our project group has developed for the redesign braking systems. Background research, objectives, and concept design developments, final design, manufacturing notes, and design verification testing data are documented for the project sponsors

    NaGdF4:Eu3+ Nanoparticles for Enhanced X-ray Excited Optical Imaging.

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    X-ray luminescent nanoparticles (NPs), including lanthanide fluorides, have been evaluated for application to deep tissue in vivo molecular imaging using optical tomography. A combination of high material density, higher atomic number and efficient NIR luminescence from compatible lanthanide dopant ions indicates that particles that consist of ALnF4 (A = alkaline, Ln = lanthanide element) may offer a very attractive class of materials for high resolution, deep tissue imaging with X-ray excitation. NaGdF4:Eu3+ NPs produced an X-ray excited luminescence that was among the most efficient of nanomaterials that have been studied thus far. We have systematically studied factors such as (a) the crystal structure that changes the lattice environment of the doped Eu3+ ions within the unit cell; and extrinsic factors such as (b) a gold coating (with attendant biocompatibility) that couples to a plasmonic excitation, and (c) changes in the NPs surface properties via changes in the pH of the suspending medium-all with a significant impact on the X-ray excited luminescence of NaGdF4:Eu3+NPs. The luminescence from an optimally doped hexagonal phase NaGdF4:Eu3+ nanoparticle was 25% more intense compared to that of a cubic structure. We observed evidence of plasmonic reabsorption of midwavelength emission by a gold coating on hexagonal NaGdF4:Eu3+ NPs; fortunately, the NaGdF4:Eu3+ @Au core-shell NPs retained the efficient 5D0→7F4 NIR (692 nm) luminescence. The NaGdF4:Eu3+ NPs exhibited sensitivity to the ambient pH when excited by X-rays, an effect not seen with UV excitation. The sensitivity to the local environment can be understood in terms of the sensitivity of the excitons that are generated by the high energy X-rays (and not by UV photons) to crystal structure and to the surface state of the particles

    The impact of repetitive unclamped inductive switching on the electrical parameters of low-voltage trench power nMOSFETs

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    The impact of hot-carrier injection (HCI) due to repetitive unclamped inductive switching (UIS) on the electrical performance of low-voltage trench power n-type MOSFETs (nMOSFETs) is assessed. Trench power nMOSFETs with 20- and 30-V breakdown voltage ratings in TO-220 packages have been fabricated and subjected to over 100 million cycles of repetitive UIS with different avalanche currents IAV at a mounting base temperature TMB of 150°C. Impact ionization during avalanche conduction in the channel causes hot-hole injection into the gate dielectric, which results in a reduction of the threshold voltage VGSTX, as the number of avalanche cycles N increases. The experimental data reveal a power-law relationship between the change in the threshold voltage ΔVGSTX and N. The results show that the power-law prefactor is directly proportional to the avalanche current. After 100 million cycles, it was observed in the 20-V rated MOSFETs that the power-law prefactor increased by 30% when IAV was increased from 160 to 225 A, thereby approximating a linear relationship. A stable subthreshold slope with avalanche cycling indicates that interface trap generation may not be an active degradation mechanism. The impact of the cell pitch on avalanche ruggedness is also investigated by testing 2.5- and 4- m cell-pitch 30-V rated MOSFETs. Measurements showed that the power-law prefactor reduced by 40% when the cell pitch was reduced by 37.5%. The improved VGSTX stability with the smaller cell-pitch MOSFETs is attributed to a lower avalanche current per unit cell resulting in less hot-hole injection and, hence, smaller VGSTX shift. The 2.5-m cell-pitch MOSFETs also show 25% improved on -state resistance RDSON, better RDSON stability, and 20% less subthreshold slope compared with the 4-m cell-pitch MOSFETs, although with 100% higher initial IDSS and less IDSS stability with avalanche cycling. These results are important for manufacturers of automotive MOSFETs where multiple avalanche occurrences over the lifetime of the MOSFET are expected

    High fat diet attenuates the anticontractile activity of aortic PVAT via a mechanism involving AMPK and reduced adiponectin secretion

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    Background and aim: Perivascular adipose tissue (PVAT) positively regulates vascular function through production of factors such as adiponectin but this effect is attenuated in obesity. The enzyme AMP-activated protein kinase (AMPK) is present in PVAT and is implicated in mediating the vascular effects of adiponectin. In this study, we investigated the effect of an obesogenic high fat diet (HFD) on aortic PVAT and whether any changes involved AMPK. Methods: Wild type Sv129 (WT) and AMPKα1 knockout (KO) mice aged 8 weeks were fed normal diet (ND) or HFD (42% kcal fat) for 12 weeks. Adiponectin production by PVAT was assessed by ELISA and AMPK expression studied using immunoblotting. Macrophages in PVAT were identified using immunohistochemistry and markers of M1 and M2 macrophage subtypes evaluated using real time-qPCR. Vascular responses were measured in endothelium-denuded aortic rings with or without attached PVAT. Carotid wire injury was performed and PVAT inflammation studied 7 days later. Key results: Aortic PVAT from KO and WT mice was morphologically indistinct but KO PVAT had more infiltrating macrophages. HFD caused an increased infiltration of macrophages in WT mice with increased expression of the M1 macrophage markers Nos2 and Il1b and the M2 marker Chil3. In WT mice, HFD reduced the anticontractile effect of PVAT as well as reducing adiponectin secretion and AMPK phosphorylation. PVAT from KO mice on ND had significantly reduced adiponectin secretion and no anticontractile effect and feeding HFD did not alter this. Wire injury induced macrophage infiltration of PVAT but did not cause further infiltration in KO mice. Conclusions: High-fat diet causes an inflammatory infiltrate, reduced AMPK phosphorylation and attenuates the anticontractile effect of murine aortic PVAT. Mice lacking AMPKα1 phenocopy many of the changes in wild-type aortic PVAT after HFD, suggesting that AMPK may protect the vessel against deleterious changes in response to HFD

    “A question of trust” and “a leap of faith”-study participants' perspectives on consent, privacy, and trust in smart home research:Qualitative study

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    BACKGROUND: Ubiquitous, smart technology has the potential to assist humans in numerous ways, including with health and social care. COVID-19 has notably hastened the move to remotely delivering many health services. A variety of stakeholders are involved in the process of developing technology. Where stakeholders are research participants, this poses practical and ethical challenges, particularly if the research is conducted in people’s homes. Researchers must observe prima facie ethical obligations linked to participants’ interests in having their autonomy and privacy respected. OBJECTIVE: This study aims to explore the ethical considerations around consent, privacy, anonymization, and data sharing with participants involved in SPHERE (Sensor Platform for Healthcare in a Residential Environment), a project for developing smart technology for monitoring health behaviors at home. Participants’ unique insights from being part of this unusual experiment offer valuable perspectives on how to properly approach informed consent for similar smart home research in the future. METHODS: Semistructured qualitative interviews were conducted with 7 households (16 individual participants) recruited from SPHERE. Purposive sampling was used to invite participants from a range of household types and ages. Interviews were conducted in participants’ homes or on-site at the University of Bristol. Interviews were digitally recorded, transcribed verbatim, and analyzed using an inductive thematic approach. RESULTS: Four themes were identified—motivation for participating; transparency, understanding, and consent; privacy, anonymity, and data use; and trust in research. Motivations to participate in SPHERE stemmed from an altruistic desire to support research directed toward the public good. Participants were satisfied with the consent process despite reporting some difficulties—recalling and understanding the information received, the timing and amount of information provision, and sometimes finding the information to be abstract. Participants were satisfied that privacy was assured and judged that the goals of the research compensated for threats to privacy. Participants trusted SPHERE. The factors that were relevant to developing and maintaining this trust were the trustworthiness of the research team, the provision of necessary information, participants’ control over their participation, and positive prior experiences of research involvement. CONCLUSIONS: This study offers valuable insights into the perspectives of participants in smart home research on important ethical considerations around consent and privacy. The findings may have practical implications for future research regarding the types of information researchers should convey, the extent to which anonymity can be assured, and the long-term duty of care owed to the participants who place trust in researchers not only on the basis of this information but also because of their institutional affiliation. This study highlights important ethical implications. Although autonomy matters, trust appears to matter the most. Therefore, researchers should be alert to the need to foster and maintain trust, particularly as failing to do so might have deleterious effects on future research

    Rocaglates as dual-targeting agents for experimental cerebral malaria

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    Cerebral malaria (CM) is a severe and rapidly progressing complication of infection by Plasmodium parasites that is associated with high rates of mortality and morbidity. Treatment options are currently few, and intervention with artemisinin (Art) has limited efficacy, a problem that is compounded by the emergence of resistance to Art in Plasmodium parasites. Rocaglates are a class of natural products derived from plants of the Aglaia genus that have been shown to interfere with eukaryotic initiation factor 4A (eIF4A), ultimately blocking initiation of protein synthesis. Here, we show that the rocaglate CR-1-31B perturbs association of Plasmodium falciparum eIF4A (PfeIF4A) with RNA. CR-1-31B shows potent prophylactic and therapeutic antiplasmodial activity in vivo in mouse models of infection with Plasmodium berghei (CM) and Plasmodium chabaudi (blood-stage malaria), and can also block replication of different clinical isolates of P. falciparum in human erythrocytes infected ex vivo, including drug-resistant P. falciparum isolates. In vivo, a single dosing of CR-1-31B in P. berghei-infected animals is sufficient to provide protection against lethality. CR-1-31B is shown to dampen expression of the early proinflammatory response in myeloid cells in vitro and dampens the inflammatory response in vivo in P. berghei-infected mice. The dual activity of CR-1-31B as an antiplasmodial and as an inhibitor of the inflammatory response in myeloid cells should prove extremely valuable for therapeutic intervention in human cases of CM.We thank Susan Gauthier, Genevieve Perreault, and Patrick Senechal for technical assistance. This work was supported by a research grant (to P.G.) from the Canadian Institutes of Health Research (CIHR) (Foundation Grant). J.P. and P.G. are supported by a James McGill Professorship salary award. D.L. is supported by fellowships from the Fonds de recherche sante Quebec, the CIHR Neuroinflammation training program. J.P. is supported by CIHR Research Grant FDN-148366. M.S. is supported by a CIHR Foundation grant. J.A.P. is supported by NIH Grant R35 GM118173. Work at the Boston University Center for Molecular Discovery is supported by Grant R24 GM111625. K.C.K. was supported by a CIHR Foundation Grant and the Canada Research Chair program. (Canadian Institutes of Health Research (CIHR); James McGill Professorship salary award; Fonds de recherche sante Quebec; CIHR Neuroinflammation training program; FDN-148366 - CIHR Research Grant; CIHR Foundation grant; R35 GM118173 - NIH; Canada Research Chair program; R24 GM111625

    Induction of Inflammation in Vascular Endothelial Cells by Metal Oxide Nanoparticles: Effect of Particle Composition

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    BACKGROUND: The mechanisms governing the correlation between exposure to ultrafine particles and the increased incidence of cardiovascular disease remain unknown. Ultrafine particles appear to cross the pulmonary epithelial barrier into the bloodstream, raising the possibility of direct contact with the vascular endothelium. OBJECTIVES: Because endothelial inflammation is critical for the development of cardiovascular pathology, we hypothesized that direct exposure of human aortic endothelial cells (HAECs) to ultrafine particles induces an inflammatory response and that this response depends on particle composition. METHODS: To test the hypothesis, we incubated HAECs for 1–8 hr with different concentrations (0.001–50 μg/mL) of iron oxide (Fe(2)O(3)), yttrium oxide (Y(2)O(3)), and zinc oxide (ZnO) nanoparticles and subsequently measured mRNA and protein levels of the three inflammatory markers intra-cellular cell adhesion molecule-1, interleukin-8, and monocyte chemotactic protein-1. We also determined nanoparticle interactions with HAECs using inductively coupled plasma mass spectrometry and transmission electron microscopy. RESULTS: Our data indicate that nanoparticle delivery to the HAEC surface and uptake within the cells correlate directly with particle concentration in the cell culture medium. All three types of nanoparticles are internalized into HAECs and are often found within intracellular vesicles. Fe(2)O(3) nanoparticles fail to provoke an inflammatory response in HAECs at any of the concentrations tested; however, Y(2)O(3) and ZnO nanoparticles elicit a pronounced inflammatory response above a threshold concentration of 10 μg/mL. At the highest concentration, ZnO nanoparticles are cytotoxic and lead to considerable cell death. CONCLUSIONS: These results demonstrate that inflammation in HAECs following acute exposure to metal oxide nanoparticles depends on particle composition
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