79 research outputs found
On Silicon Group Elements Ejected by Supernovae Type Ia
There is compelling evidence that the peak brightness of a Type Ia supernova
is affected by the electron fraction Ye at the time of the explosion. The
electron fraction is set by the aboriginal composition of the white dwarf and
the reactions that occur during the pre explosive convective burning. To date,
determining the makeup of the white dwarf progenitor has relied on indirect
proxies, such as the average metallicity of the host stellar population. In
this paper, we present analytical calculations supporting the idea that the
electron fraction of the progenitor systematically influences the
nucleosynthesis of silicon group ejecta in Type Ia supernovae. In particular,
we suggest the abundances generated in quasi nuclear statistical equilibrium
are preserved during the subsequent freezeout. This allows one to potential
recovery of Ye at explosion from the abundances recovered from an observed
spectra. We show that measurement of 28Si, 32S, 40Ca, and 54Fe abundances can
be used to construct Ye in the silicon rich regions of the supernovae. If these
four abundances are determined exactly, they are sufficient to recover Ye to 6
percent. This is because these isotopes dominate the composition of
silicon-rich material and iron rich material in quasi nuclear statistical
equilibrium. Analytical analysis shows that the 28Si abundance is insensitive
to Ye, the 32S abundance has a nearly linear trend with Ye, and the 40Ca
abundance has a nearly quadratic trend with Ye. We verify these trends with
post-processing of 1D models and show that these trends are reflected in model
synthetic spectra.Comment: Submitted to the Ap
Giant cell tumor of the anterior rib masquerading as a breast mass: a case report and review of current literature
EZH2 is a sensitive marker of malignancy in salivary gland tumors
BACKGROUND: The immunohistochemical detection of Enhancer of zeste homologue 2 (EZH2) proved to be a useful tool to recognize the malignant nature of tumors in a wide variety of neoplasms. The histological diagnostics of salivary gland tumors is a challenging task, and a reliable marker of malignancy would be extremely helpful. METHODS: EZH2 expression was investigated in 54 malignant and 40 benign salivary gland tumors of various histological types by standard immunohistochemistry. RESULTS: The majority (n = 52) of the malignant tumors stained positively, while all the investigated benign tumors were negative for EZH2. CONCLUSIONS: EZH2 expression in salivary gland tumors, similarly to the tumors of other organs is not characteristic for any tumor type, but is a solid marker of the malignant nature of the tumors
14-3-3theta Protects against Neurotoxicity in a Cellular Parkinson's Disease Model through Inhibition of the Apoptotic Factor Bax
Disruption of 14-3-3 function by alpha-synuclein has been implicated in Parkinson's disease. As 14-3-3s are important regulators of cell death pathways, disruption of 14-3-3s could result in the release of pro-apoptotic factors, such as Bax. We have previously shown that overexpression of 14-3-3θ reduces cell loss in response to rotenone and MPP+ in dopaminergic cell culture and reduces cell loss in transgenic C. elegans that overexpress alpha-synuclein. In this study, we investigate the mechanism for 14-3-3θ's neuroprotection against rotenone toxicity. While 14-3-3s can inhibit many pro-apoptotic factors, we demonstrate that inhibition of one factor in particular, Bax, is important to 14-3-3s' protection against rotenone toxicity in dopaminergic cells. We found that 14-3-3θ overexpression reduced Bax activation and downstream signaling events, including cytochrome C release and caspase 3 activation. Pharmacological inhibition or shRNA knockdown of Bax provided protection against rotenone, comparable to 14-3-3θ's neuroprotective effects. A 14-3-3θ mutant incapable of binding Bax failed to protect against rotenone. These data suggest that 14-3-3θ's neuroprotective effects against rotenone are at least partially mediated by Bax inhibition and point to a potential therapeutic role of 14-3-3s in Parkinson's disease
Autoimmune pulmonary alveolar proteinosis co-existing with breast cancer: a case report
Introduction. Pulmonary alveolar proteinosis is a rare pulmonary disease characterized by excessive alveolar accumulation of surfactant due to defective alveolar clearance by macrophages. There are only a few published case reports of pulmonary alveolar proteinosis occurring in association with solid cancers. To the best of our knowledge, there are no previously reported cases of pulmonary alveolar proteinosis associated with breast cancer. Case presentation. A 48-year-old Asian woman, a nonsmoker, presented to our institution with a right breast mass. Biopsy examination of the lesion revealed scirrhous carcinoma. A chest computed tomography scan for metastases showed abnormal shadows in both upper lung fields. As a result of flexible fiberscopic bronchoscopy, this patient was diagnosed as having pulmonary alveolar proteinosis. This case was categorized as autoimmune pulmonary alveolar proteinosis due to the positive anti-granulocyte-macrophage colony-stimulating factor antibody. Pulmonary alveolar proteinosis decreased gradually after mastectomy. Conclusions: The present case involved the coincident occurrence of autoimmune pulmonary alveolar proteinosis with breast cancer; breast cancer may be a factor during pulmonary alveolar proteinosis development
Top-down estimates of European CH<sub>4</sub> and N<sub>2</sub>O emissions based on four different inverse models
European CH4 and N2O emissions are estimated
for 2006 and 2007 using four inverse modelling systems,
based on different global and regional Eulerian and Lagrangian
transport models. This ensemble approach is designed
to provide more realistic estimates of the overall uncertainties
in the derived emissions, which is particularly important
for verifying bottom-up emission inventories.
We use continuous observations from 10 European stations
(including 5 tall towers) for CH4 and 9 continuous stations
for N2O, complemented by additional European and
global discrete air sampling sites. The available observations
mainly constrain CH4 and N2O emissions from northwestern
and eastern Europe. The inversions are strongly
driven by the observations and the derived total emissions
of larger countries show little dependence on the emission
inventories used a priori.
Three inverse models yield 26–56% higher total CH4
emissions from north-western and eastern Europe compared
to bottom-up emissions reported to the UNFCCC, while one
model is close to the UNFCCC values. In contrast, the inverse
modelling estimates of European N2O emissions are in
general close to the UNFCCC values, with the overall range
from all models being much smaller than the UNFCCC uncertainty
range for most countries. Our analysis suggests that
the reported uncertainties for CH4 emissions might be underestimated,
while those for N2O emissions are likely overestimated.JRC.H.2-Air and Climat
Renal cortical necrosis in an infant
A 10-month-old infant developed renal cortical necrosis, leading to nephrocalcinosis shown radiographically. The infant survived after prolonged peritoneal dialysis
Pulmonary embolism due to invasive aspergillosis in a child with acute myelogenous leukemia
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