20 research outputs found
PUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry: Nucleosynthesis Yields
Core-collapse supernovae (CCSNe) are the extremely energetic deaths of
massive stars. They play a vital role in the synthesis and dissemination of
many heavy elements in the universe. In the past, CCSN nucleosynthesis
calculations have relied on artificial explosion methods that do not adequately
capture the physics of the innermost layers of the star. The PUSH method,
calibrated against SN1987A, utilizes the energy of heavy-flavor neutrinos
emitted by the proto-neutron star (PNS) to trigger parametrized explosions.
This makes it possible to follow the consistent evolution of the PNS and to
ensure a more accurate treatment of the electron fraction of the ejecta. Here,
we present the Iron group nucleosynthesis results for core-collapse supernovae,
exploded with PUSH, for two different progenitor series. Comparisons of the
calculated yields to observational metal-poor star data are also presented.
Nucleosynthesis yields will be calculated for all elements and over a wide
range of progenitor masses. These yields can be immensely useful for models of
galactic chemical evolution.Comment: 3 pages, 3 figures, poster presentation to appear in the proceedings
of the 14th International Symposium on Nuclei in the Cosmos (NIC-XIV), Ed. S.
Kubono, JPS (Japan Physical Society
Explosion Dynamics of Parametrized Spherically Symmetric Core-Collapse Supernova Simulations
We report on a method, PUSH, for triggering core-collapse supernova (CCSN)
explosions of massive stars in spherical symmetry. This method provides a
framework to study many important aspects of core collapse supernovae: the
effects of the shock passage through the star, explosive supernova
nucleosynthesis and the progenitor-remnant connection. Here we give an overview
of the method, compare the results to multi-dimensional simulations and
investigate the effects of the progenitor and the equation of state on black
hole formation.Comment: Proceedings for Nuclei in the Cosmos XIV, Niigata, Japan (2016
BERT for Long Documents: A Case Study of Automated ICD Coding
Transformer models have achieved great success across many NLP problems.
However, previous studies in automated ICD coding concluded that these models
fail to outperform some of the earlier solutions such as CNN-based models. In
this paper we challenge this conclusion. We present a simple and scalable
method to process long text with the existing transformer models such as BERT.
We show that this method significantly improves the previous results reported
for transformer models in ICD coding, and is able to outperform one of the
prominent CNN-based methods
Emotion-Controllable Generalized Talking Face Generation
Despite the significant progress in recent years, very few of the AI-based
talking face generation methods attempt to render natural emotions. Moreover,
the scope of the methods is majorly limited to the characteristics of the
training dataset, hence they fail to generalize to arbitrary unseen faces. In
this paper, we propose a one-shot facial geometry-aware emotional talking face
generation method that can generalize to arbitrary faces. We propose a graph
convolutional neural network that uses speech content feature, along with an
independent emotion input to generate emotion and speech-induced motion on
facial geometry-aware landmark representation. This representation is further
used in our optical flow-guided texture generation network for producing the
texture. We propose a two-branch texture generation network, with motion and
texture branches designed to consider the motion and texture content
independently. Compared to the previous emotion talking face methods, our
method can adapt to arbitrary faces captured in-the-wild by fine-tuning with
only a single image of the target identity in neutral emotion.Comment: Accepted at IJCAI 202
Differential packaging of inflammatory cytokines/ chemokines and oxidative stress modulators in U937 and U1 macrophages-derived extracellular vesicles upon exposure to tobacco constituents.
Smoking, which is highly prevalent in HIV-infected populations, has been shown to exacerbate HIV replication, in part via the cytochrome P450 (CYP)-induced oxidative stress pathway. Recently, we have shown that extracellular vesicles (EVs), derived from tobacco- and/or HIV-exposed macrophages, alter HIV replication in macrophages by cell-cell interactions. We hypothesize that cigarette smoke condensate (CSC) and/or HIV-exposed macrophage-derived EVs carry relatively high levels of pro-oxidant and pro-inflammatory cargos and/or low levels of antioxidant and anti-inflammatory cargos, which are key mediators for HIV pathogenesis. Therefore, in this study, we investigated differential packaging of pro- and anti-inflammatory cytokines/chemokines and pro- and anti-oxidant contents in EVs after CSC exposure to myeloid cells (uninfected U937 and HIV-infected U1 cells). Our results showed that relatively long to short exposures with CSC increased the expression of cytokines in EVs isolated from HIV-infected U1 macrophages. Importantly, pro-inflammatory cytokines, especially IL-6, were highly packaged in EVs isolated from HIV-infected U1 macrophages upon both long and short-term CSC exposures. In general, anti-inflammatory cytokines, particularly IL-10, had a lower packaging in EVs, while packaging of chemokines was mostly increased in EVs upon CSC exposure in both HIV-infected U1 and uninfected U937 macrophages. Moreover, we observed higher expression of CYPs (1A1 and 1B1) and lower expression of antioxidant enzymes (SOD-1 and catalase) in EVs from HIV-infected U1 macrophages than in uninfected U937 macrophages. Together, they are expected to increase oxidative stress factors in EVs derived from HIV-infected U1 cells. Taken together, our results suggest packaging of increased level of oxidative stress and inflammatory elements in the EVs upon exposure to tobacco constituents and/or HIV to myeloid cells, which would ultimately enhance HIV replication in macrophages via cell-cell interactions
Monocyte-derived exosomes upon exposure to cigarette smoke condensate alter their characteristics and show protective effect against cytotoxicity and HIV-1 replication
Abstract Smoking is known to exacerbate HIV-1 pathogenesis, especially in monocytes, through the oxidative stress pathway. Exosomes are known to alter HIV-1 pathogenesis through inter-cellular communication. However, the role of exosomes in smoking-mediated HIV-1 pathogenesis is unknown. In this study, we investigated the effect of cigarette smoke condensate (CSC) on the characteristics of monocyte-derived exosomes and their influence on HIV-1 replication. Initially, we demonstrated that CSC reduced total protein and antioxidant capacity in exosomes derived from HIV-1-infected and uninfected macrophages. The exosomes from CSC-treated uninfected cells showed a protective effect against cytotoxicity and viral replication in HIV-1-infected macrophages. However, exosomes derived from HIV-1-infected cells lost their protective capacity. The results suggest that the exosomal defense is likely to be more effective during the early phase of HIV-1 infection and diminishes at the latter phase. Furthermore, we showed CSC-mediated upregulation of catalase in exosomes from uninfected cells, with a decrease in the levels of catalase and PRDX6 in exosomes derived from HIV-1-infected cells. These results suggest a potential role of antioxidant enzymes, which are differentially packaged into CSC-exposed HIV-1-infected and uninfected cell-derived exosomes, on HIV-1 replication of recipient cells. Overall, our study suggests a novel role of exosomes in tobacco-mediated HIV-1 pathogenesis