262 research outputs found
A general moment NRIXS approach to the determination of equilibrium Fe isotopic fractionation factors: application to goethite and jarosite
We measured the reduced partition function ratios for iron isotopes in
goethite FeO(OH), potassium-jarosite KFe3(SO4)2(OH)6, and hydronium-jarosite
(H3O)Fe3(SO4)2(OH)6, by Nuclear Resonant Inelastic X-Ray Scattering (NRIXS,
also known as Nuclear Resonance Vibrational Spectroscopy -NRVS- or Nuclear
Inelastic Scattering -NIS) at the Advanced Photon Source. These measurements
were made on synthetic minerals enriched in 57Fe. A new method (i.e., the
general moment approach) is presented to calculate {\beta}-factors from the
moments of the NRIXS spectrum S(E). The first term in the moment expansion
controls iron isotopic fractionation at high temperature and corresponds to the
mean force constant of the iron bonds, a quantity that is readily measured and
often reported in NRIXS studies.Comment: 38 pages, 2 tables, 8 figures. In press at Geochimica et Cosmochimica
Acta. Appendix C contains new derivations relating the moments of the iron
PDOS to the moments of the excitation probability function measured in
Nuclear Resonant Inelastic X-ray Scatterin
Assessment of ion kinetic effects in shock-driven inertial confinement fusion implosions using fusion burn imaging
The significance and nature of ion kinetic effects in D3He-filled, shock-driven inertial confinement
fusion implosions are assessed through measurements of fusion burn profiles. Over this series of
experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number,
NK) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma
conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match
measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured
the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially
resolved measurements of the fusion burn are used to examine kinetic ion transport effects in
greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional
integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison
of measured and simulated burn profiles shows that models including ion transport effects
are able to better match the experimental results. In implosions characterized by large Knudsen
numbers (NK3), the fusion burn profiles predicted by hydrodynamics simulations that exclude
ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally
observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that
includes a model of ion diffusion is able to qualitatively match the measured profile shapes.
Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the
observed trends, though further refinement of the models is needed for a more complete and
quantitative understanding of ion kinetic effects
Multifunctional platform based on electrospun nanofibers and plasmonic hydrogel. A smart nanostructured pillow for near-infrared light-driven biomedical applications
Multifunctional nanomaterials with the ability to respond to near-infrared (NIR) light stimulation are vital for the development of highly efficient biomedical nanoplatforms with a polytherapeutic approach. Inspired by the mesoglea structure of jellyfish bells, a biomimetic multifunctional nanostructured pillow with fast photothermal responsiveness for NIR light-controlled on-demand drug delivery is developed. We fabricate a nanoplatform with several hierarchical levels designed to generate a series of controlled, rapid, and reversible cascade-like structural changes upon NIR light irradiation. The mechanical contraction of the nanostructured platform, resulting from the increase of temperature to 42 °C due to plasmonic hydrogel-light interaction, causes a rapid expulsion of water from the inner structure, passing through an electrospun membrane anchored onto the hydrogel core. The mutual effects of the rise in temperature and water flow stimulate the release of molecules from the nanofibers. To expand the potential applications of the biomimetic platform, the photothermal responsiveness to reach the typical temperature level for performing photothermal therapy (PTT) is designed. The on-demand drug model penetration into pig tissue demonstrates the efficiency of the nanostructured platform in the rapid and controlled release of molecules, while the high biocompatibility confirms the pillow potential for biomedical applications based on the NIR light-driven multitherapy strategy
Scaled laboratory experiments explain the kink behaviour of the Crab Nebula jet
The remarkable discovery by the Chandra X-ray observatory that the Crab nebula's jet periodically changes direction provides a challenge to our understanding of astrophysical jet dynamics. It has been suggested that this phenomenon may be the consequence of magnetic fields and magnetohydrodynamic instabilities, but experimental demonstration in a controlled laboratory environment has remained elusive. Here we report experiments that use high-power lasers to create a plasma jet that can be directly compared with the Crab jet through well-defined physical scaling laws. The jet generates its own embedded toroidal magnetic fields; as it moves, plasma instabilities result in multiple deflections of the propagation direction, mimicking the kink behaviour of the Crab jet. The experiment is modelled with three-dimensional numerical simulations that show exactly how the instability develops and results in changes of direction of the jet
Transient Receptor Potential (TRP) and Cch1-Yam8 Channels Play Key Roles in the Regulation of Cytoplasmic Ca2+ in Fission Yeast
The regulation of cytoplasmic Ca2+ is crucial for various cellular processes. Here, we examined the cytoplasmic Ca2+ levels in living fission yeast cells by a highly sensitive bioluminescence resonance energy transfer-based assay using GFP-aequorin fusion protein linked by 19 amino acid. We monitored the cytoplasmic Ca2+ level and its change caused by extracellular stimulants such as CaCl2 or NaCl plus FK506 (calcineurin inhibitor). We found that the extracellularly added Ca2+ caused a dose-dependent increase in the cytoplasmic Ca2+ level and resulted in a burst-like peak. The overexpression of two transient receptor potential (TRP) channel homologues, Trp1322 or Pkd2, markedly enhanced this response. Interestingly, the burst-like peak upon TRP overexpression was completely abolished by gene deletion of calcineurin and was dramatically decreased by gene deletion of Prz1, a downstream transcription factor activated by calcineurin. Furthermore, 1 hour treatment with FK506 failed to suppress the burst-like peak. These results suggest that the burst-like Ca2+ peak is dependent on the transcriptional activity of Prz1, but not on the direct TRP dephosphorylation. We also found that extracellularly added NaCl plus FK506 caused a synergistic cytosolic Ca2+ increase that is dependent on the inhibition of calcineurin activity, but not on the inhibition of Prz1. The synergistic Ca2+ increase is abolished by the addition of the Ca2+ chelator BAPTA into the media, and is also abolished by deletion of the gene encoding a subunit of the Cch1-Yam8 Ca2+ channel complex, indicating that the synergistic increase is caused by the Ca2+ influx from the extracellular medium via the Cch1-Yam8 complex. Furthermore, deletion of Pmk1 MAPK abolished the Ca2+ influx, and overexpression of the constitutively active Pek1 MAPKK enhanced the influx. These results suggest that Pmk1 MAPK and calcineurin positively and negatively regulate the Cch1-Yam8 complex, respectively, via modulating the balance between phosphorylation and dyphosphorylation state
Sobre a (im)prescritibilidade da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa
TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Jurídicas. Direito.O presente trabalho objetiva dirimir a dúvida existente acerca da sujeição da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa ao instituto da prescrição. Tal incerteza surge a partir da redação da ressalva contida no artigo 37, § 5º, da Constituição da República Federativa do Brasil, que possibilita variadas interpretações, algumas defendendo a imprescritibilidade de tal pretensão, outras advogando a tese da sujeição de tal pretensão a lapso prescricional. Com o fito de se concluir pelo entendimento mais condizente à ordem jurídico-normativa brasileira, divide-se o estudo em três capítulos principais. No primeiro, são delineados o conceito e a finalidade da prescrição, apresentando-se a garantia da segurança jurídica como sendo seu fundamento constitucional. Em seguida, são explanadas as noções de supremacia do interesse público e segurança jurídica, entendidas por boa parte dos estudiosos como os dois princípios a partir dos quais deve ser analisada a questão. Por fim, no terceiro e último capítulo, depois de serem descritas as principais interpretações que podem derivar da leitura do dispositivo, chega-se ao entendimento pela conformação da pretensão estudada ao manto prescricional. Esta acepção parece melhor se amoldar aos contornos pretendidos pelo ordenamento jurídico-constitucional contemporâneo para a construção de um Direito Administrativo efetivamente democrático, com a sobrevalorização dos direitos fundamentais, individuais e coletivos, e a realização da ideia de supremacia da Constituição. No plano legal e normativo, a compreensão pela prescritibilidade afigura-se coerente à própria construção histórica do comando constitucional, com a delimitação de dois regimes prescricionais distintos para as pretensões originadas com a prática de ato de improbidade. Da mesma forma, a identificação do ressarcimento como consequência, e não sanção, do ato ímprobo, bem como a evolução do tratamento dado à matéria pelo Supremo Tribunal Federal parecem caminhar no mesmo sentido interpretativo
Bio-nanotechnology application in wastewater treatment
The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed
Catching the therapeutic window of opportunity in early initial-onset Vogt�Koyanagi�Harada uveitis can cure the disease
Purpose: Vogt�Koyanagi�Harada (VKH) disease is a primary autoimmune granulomatous choroiditis that begins in the choroidal stroma. The aim of this review was to gather a body of evidence for the concept of a window of therapeutic opportunity, defined as a time interval following initial-onset disease during which adequate treatment will substantially modify the disease outcome and possibly even lead to cure, similar to what has been described for rheumatoid arthritis. Methods: We reviewed the literature and consulted leading experts in VKH disease to determine the consensus for the notion of a therapeutic window of opportunity in VKH disease. Results: We found a substantial body of evidence in the literature that a therapeutic window of opportunity exists for initial-onset acute uveitis associated with VKH disease. The disease outcome can be substantially improved if dual systemic steroidal and non-steroidal immunosuppressants are given within 2�3 weeks of the onset of initial VKH disease, avoiding evolution to chronic disease and development of �sunset glow fundus.� Several studies additionally report series in which the disease could be cured, using such an approach. Conclusions: There is substantial evidence for a therapeutic window of opportunity in initial-onset acute VKH disease. Timely and adequate treatment led to substantial improvement of disease outcome and prevented chronic evolution and �sunset glow fundus,� and very early treatment led to the cure after discontinuation of therapy in several series, likely due to the fact that the choroid is the sole origin of inflammation in VKH disease. © 2018 The Author(s
Emergent versus delayed lithotripsy for obstructing ureteral stones: a cumulative analysis of comparative studies
Objective To analyze the current evidence on the use of ureteroscopy (URS) and extracorporeal shock wave lithotripsy (ESWL) for the management of obstructing ureteral stones in emergent setting.
Methods A systematic literature review was performed up to June 2016 using Pubmed and Ovid databases to identify pertinent studies. The PRISMA criteria were followed for article selection. Separate searches were done using a combinations of several search terms: "laser lithotripsy", "ureteroscopy", "extracorporeal shock wave lithotripsy", "ESWL", "rapid", "immediate", "early", "delayed", "late", "ureteral stones", "kidney stones", "renal stones". Only titles related to emergent/rapid/immediate/early (as viably defined in each study) versus delayed/late treatment of ureteral stones with either URS and/or ESWL were considered for screening. Demographics and operative outcomes were compared between emergent and delayed lithotripsy. RevMan review manager software was used to perform data analysis.
Results Four studies comparing emergent (n = 526) versus delayed (n = 987) URS and six studies comparing emergent (n = 356) versus delayed (n = 355) SWL were included in the analysis. Emergent URS did not show any significant difference in terms of stone-free rate (91.2 versus 90.9%; OR 1.04; CI 0.71, 1.52; p = 0.84), complication rate (8.7% for emergent versus 11.5% for delayed; OR 0.94; CI 0.65, 1.36; p = 0.74) and need for auxiliary procedures (OR 0.85; CI 0.42, 1.7; p = 0.85) when compared to delayed URS. Emergent ESWL was associated with a higher likelihood of stone free status (OR 2.2; CI 1.55, 3.17; p < 0.001) and a lower likelihood of need for auxiliary maneuvers (OR 0.49; CI 0.33, 0.72; p < 0.001) than the delayed procedure. No differences in complication rates were noticed between the emergent and delayed ESWL (p = 0.37).
Conclusions Emergent lithotripsy, either ureteroscopic or extracorporeal, can be offered as an effective and safe treatment for patients with symptomatic ureteral stone. If amenable to ESWL, based on stone and patient characteristics, an emergent approach should be strongly considered. Ureteroscopy in the emergent setting is mostly reserved for distally located stones. The implementation of these therapeutic approaches is likely to be dictated by their availability.info:eu-repo/semantics/publishedVersio
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