211 research outputs found

    Crystal field splitting on D↔S transitions of atomic manganese isolated in solid krypton

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    Narrow excitation features present on the [Ar]3d⁶4s¹ a⁶D(J=9/2–1/2)←[Ar]3d⁵4s² a⁶S1/2 transitions of manganese atoms isolated in solid Kr are analyzed within the framework of weak crystal field splitting. Use of the Wp optical lineshape function allowed identification of multiple zero-phonon lines for individual spin-orbit J states of the a⁶D←a⁶S transition recorded with laser-induced excitation spectroscopy. Excellent agreement exists between the predicted crystal field splitting patterns for the J levels of the a⁶D state isolated in the «red» tetravacancy site of solid Kr. The tetrahedral crystal field of the «red» trapping site splits J>3/2 levels of the a⁶DJ and a⁴D₇/₂ states by approximately 30 cm⁻¹. This report represents the first definitive evidence of crystal field splitting, induced by the weak van der Waals interactions between a neutral metal atom and the rare gas atoms surrounding it in a well defined solid state site

    The role of spin-orbit coupling in the optical spectroscopy of atomic sodium isolated in solid xenon

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    Molecular dynamics calculations, based on the diatomics-in-molecules method, have been used to probe the manifestations of spin-orbit (SO) coupling in the experimental absorption bands of atomic sodium isolated in solid xenon. Inclusion of SO coupling of –320 cm−1 in spectral simulations of the 3p 2P 3s 2S transition leads to unequal band spacings which very closely match the asymmetrical bandshape observed for blue single vacancy (SV) site occupancy. This SO value, extracted in a previous MCD study, reveals the dramatic change in the effective SO coupling constant of the Na atom (from the gas phase value of +17 cm−1 ) in solid Xe when it is close to the 12 xenon atoms in the first surrounding sphere. In contrast, the symmetrical three-fold split band of the red tetra vacancy (TV) site in Na/Xe is not affected nearly as much by SO coupling. This reflects a greatly reduced “external heavy atom” effect when the 24 Xe atoms surrounding the Na atom in TV are located at greater distances. The contrasting behavior of sodium in the SV and TV sites suggests a strong dependence of the SO coupling strength on the Na–Xe distance

    Dissolving microneedles for DNA vaccination: Improving functionality via polymer characterisation and RALA complexation

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    DNA vaccination holds the potential to treat or prevent nearly any immunogenic disease, including cancer. To date, these vaccines have demonstrated limited immunogenicity in vivo due to the absence of a suitable delivery system which can protect DNA from degradation and improve transfection efficiencies in vivo. Recently, microneedles have been described as a novel physical delivery technology to enhance DNA vaccine immunogenicity. Of these devices, dissolvable microneedles promise a safe, pain-free delivery system which may simultaneously improve DNA stability within a solid matrix and increase DNA delivery compared to solid arrays. However, to date little work has directly compared the suitability of different dissolvable matrices for formulation of DNA-loaded microneedles. Therefore, the current study examined the ability of 4 polymers to formulate mechanically robust, functional DNA loaded dissolvable microneedles. Additionally, complexation of DNA to a cationic delivery peptide, RALA, prior to incorporation into the dissolvable matrix was explored as a means to improve transfection efficacies following release from the polymer matrix. Our data demonstrates that DNA is degraded following incorporation into PVP, but not PVA matrices. The complexation of DNA to RALA prior to incorporation into polymers resulted in higher recovery from dissolvable matrices, and increased transfection efficiencies in vitro. Additionally, RALA/DNA nanoparticles released from dissolvable PVA matrices demonstrated up to 10-fold higher transfection efficiencies than the corresponding complexes released from PVP matrices, indicating that PVA is a superior polymer for this microneedle application

    Research Liaisons: the next layer of Facilitation

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    This item includes a conference paper and the accompanying presentation given at the conference. The presentation was prerecorded.Research productivity has been greatly enhanced by Research Computing Facilitation teams to help researchers maximize their use of advanced cyberinfrastructure. However, researchers have more technology needs than just advanced cyberinfrastructure, such as data management and instrument device support. To address this, the Academic Engagement team in Michigan Medicine added Research Liaisons as another layer of human support on top of the Facilitation team. The Liaisons are relationship builders. They are assigned to departments to build deep relationships with them and start proactively addressing labs’ technology needs. They also build relationships with other teams, notably enterprise storage, enterprise networking, and research core facilities. These relationships allow Liaisons to provide a connective tissue between the researchers and IT teams.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170574/1/McCaffrey et al. - 2021 - Research Liaisons the next layer of Facilitation.pdfDescription of McCaffrey et al. - 2021 - Research Liaisons the next layer of Facilitation.pdf : Main articleSEL

    DNA vaccination for cervical cancer: Strategic optimisation of RALA mediated gene delivery from a biodegradable microneedle system.

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    Dissolvable microneedles can be employed to deliver DNA to antigen presenting cells within the skin. However, this technology faces two main challenges: the poor transfection efficacy of pDNA following release from the microneedle matrix, and the limited loading capacity of the micron-scale devices. Two-tier delivery systems combining microneedle platforms and DNA delivery vectors have increased efficacy but the challenge of increasing the loading capacity remains. This study utilised lyophilisation to increase the loading of RALA/pDNA nanoparticles within dissolvable PVA microneedles. As a result, delivery was significantly enhanced in vivo into an appropriate range for DNA vaccination (∼50 μg per array). Furthermore, modifying the manufacturing process was not detrimental to the microneedle mechanical properties or cargo functionality. It was demonstrated that arrays retained mechanical and functional stability over short term storage, and were able to elicit gene expression in vitro and in vivo. Finally, treatment with this novel formulation significantly retarded the growth of established tumours, and proved superior to standard intramuscular injection in a preclinical model of cervical cancer

    Does teacher evaluation based on student performance predict motivation, well-being, and ill-being?

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    This study tests an explanatory model based on self-determination theory, which posits that pressure experienced by teachers when they are evaluated based on their students' academic performance will differentially predict teacher adaptive and maladaptive motivation, well-being, and ill-being. A total of 360 Spanish physical education teachers completed a multi-scale inventory. We found support for a structural equation model that showed that perceived pressure predicted teacher autonomous motivation negatively, predicted amotivation positively, and was unrelated to controlled motivation. In addition, autonomous motivation predicted vitality positively and exhaustion negatively, whereas controlled motivation and amotivation predicted vitality negatively and exhaustion positively. Amotivation significantly mediated the relation between pressure and vitality and between pressure and exhaustion. The results underline the potential negative impact of pressure felt by teachers due to this type of evaluation on teacher motivation and psychological health

    Essential Role of TGF-β/Smad Pathway on Statin Dependent Vascular Smooth Muscle Cell Regulation

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    BACKGROUND: The 3-hydroxy-3-methylglutaryl CoA reductase inhibitors (also called statins) exert proven beneficial effects on cardiovascular diseases. Recent data suggest a protective role for Transforming Growth Factor-beta (TGF-beta) in atherosclerosis by regulating the balance between inflammation and extracellular matrix accumulation. However, there are no studies about the effect of statins on TGF-beta/Smad pathway in atherosclerosis and vascular cells. METHODOLOGY: In cultured vascular smooth muscle cells (VSMCs) statins enhanced Smad pathway activation caused by TGF-beta. In addition, statins upregulated TGF-beta receptor type II (TRII), and increased TGF-beta synthesis and TGF-beta/Smad-dependent actions. In this sense, statins, through Smad activation, render VSMCs more susceptible to TGF-beta induced apoptosis and increased TGF-beta-mediated ECM production. It is well documented that high doses of statins induce apoptosis in cultured VSMC in the presence of serum; however the precise mechanism of this effect remains to be elucidated. We have found that statins-induced apoptosis was mediated by TGF-beta/Smad pathway. Finally, we have described that RhoA inhibition is a common intracellular mechanisms involved in statins effects. The in vivo relevance of these findings was assessed in an experimental model of atherosclerosis in apolipoprotein E deficient mice: Treatment with Atorvastatin increased Smad3 phosphorylation and TRII overexpression, associated to elevated ECM deposition in the VSMCs within atheroma plaques, while apoptosis was not detected. CONCLUSIONS: Statins enhance TGF-beta/Smad pathway, regulating ligand levels, receptor, main signaling pathway and cellular responses of VSMC, including apoptosis and ECM accumulation. Our findings show that TGF-beta/Smad pathway is essential for statins-dependent actions in VSMCs
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