766 research outputs found
Ion kinetics of plasma interchange reconnection in the lower solar corona
The exploration of the inner heliosphere by Parker Solar Probe has revealed a
highly structured solar wind with ubiquitous deflections from the Parker
spiral, known as switchbacks. Interchange reconnection (IR) may play an
important role in generating these switchbacks by forming unstable particle
distributions that generate wave activity that in turn may evolve to such
structures. IR occurs in very low beta plasmas and in the presence of strong
guiding fields. Although IR is unlikely to release enough energy to provide an
important contribution to the heating and acceleration of the solar wind, it
affects the way the solar wind is connected to its sources, connecting open
field lines to regions of closed fields. This "switching on" provides a
mechanism by which plasma near coronal hole boundaries can mix with that
trapped inside the closed loops. This mixing can lead to a new energy balance.
It may significantly change the characteristics of the solar wind because this
plasma is already pre-heated and can potentially have quite different density
and particle distributions. It not only replenishes the solar wind, but also
affects the electric field, which in turn affects the energy balance. This
interpenetration is manifested by the formation of a bimodal ion distribution,
with a core and a beam-like population. Such distributions are indeed
frequently observed by the Parker Solar Probe. Here we provide a first step
towards assessing the role of such processes in accelerating and heating the
solar wind.Comment: Accepted in Parker Solar Probe Focus Issue (ApJ
HDAC Regulates Transcription at the Outset of Axolotl Tail Regeneration
Tissue regeneration is associated with complex changes in gene expression and post-translational modifications of proteins, including transcription factors and histones that comprise chromatin. We tested 172 compounds designed to target epigenetic mechanisms in an axolotl (Ambystoma mexicanum) embryo tail regeneration assay. A relatively large number of compounds (N = 55) inhibited tail regeneration, including 18 histone deacetylase inhibitors (HDACi). In particular, romidepsin, an FDA-approved anticancer drug, potently inhibited tail regeneration when embryos were treated continuously for 7 days. Additional experiments revealed that romidepsin acted within a very narrow, post-injury window. Romidepsin treatment for only 1-minute post amputation inhibited regeneration through the first 7 days, however after this time, regeneration commenced with variable outgrowth of tailfin tissue and abnormal patterning. Microarray analysis showed that romidepsin altered early, transcriptional responses at 3 and 6-hour post-amputation, especially targeting genes that are implicated in tumor cell death, as well as genes that function in the regulation of transcription, cell differentiation, cell proliferation, pattern specification, and tissue morphogenesis. Our results show that HDAC activity is required at the time of tail amputation to regulate the initial transcriptional response to injury and regeneration
Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target
Multiplicities of charged pions and unidentified hadrons produced in
deep-inelastic scattering were measured in bins of the Bjorken scaling variable
, the relative virtual-photon energy and the relative hadron energy .
Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam and
an isoscalar target (LiD). They cover the kinematic domain in the photon
virtuality > 1(GeV/c, , and . In addition, a leading-order pQCD analysis was performed using the
pion multiplicity results to extract quark fragmentation functions
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
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