16 research outputs found
Dark Matter Sees The Light
We construct a Dark Matter (DM) annihilation module that can encompass the
predictions from a wide array of models built to explain the recently reported
PAMELA and ATIC/PPB-BETS excesses. We present a detailed analysis of the
injection spectrums for DM annihilation and quantitatively demonstrate effects
that have previously not been included from the particle physics perspective.
With this module we demonstrate the parameter space that can account for the
aforementioned excesses and be compatible with existing high energy gamma ray
and neutrino experiments. However, we find that it is relatively generic to
have some tension between the results of the HESS experiment and the
ATIC/PPB-BETS experiments within the context of annihilating DM. We discuss
ways to alleviate this tension and how upcoming experiments will be able to
differentiate amongst the various possible explanations of the purported
excesses.Comment: 47 pages, 17 figure
Analysis by fast-atom bombardment tandem mass spectrometry of phosphatidylcholine isolated from heart mitochondrial fractions: Evidence of incorporation of monohydroxylated fatty acyl moieties
Phosphatidylcholine (PC) is one of the main phospholipids present in mitochondrial membranes. According to current knowledge, the predominant fatty acyl moieties in this phospholipid are 16, 18, 20, or 22 carbon atoms long with chains that contain only carbon and hydrogen atoms. We have conducted a detailed analysis of the fatty acid substituents of the phospholipids present in mitochondrial fractions by using fast-atom bombardment tandem mass spectrometry. Six monohydroxylated C-16 and C-18 fatty acyl moieties were found in PC extracted from mitochondrial fractions of rat heart. The structure of one of these monohydroxylated fatty acids has been elucidated and corresponded to 12-hydroxy 9-octadecenoic acid. indications that concern the structure of the five other monohydroxylated fatty acids are presented. These monohydroxylated fatty acyl groups are preferentially associated in the PC molecule with C-18 and C-20 fatty acyl moieties. We present arguments to suggest that the formation of these compounds is probably not due to a free-radical initiated mechanism. The potential implication of these monohydroxylated fatty acids in several physiological functions is suggested by the fact that free hydroxylated fatty acids that are identical or closely related to those found in the mitochondrial fractions possess various biological activities
Effects of experimental parameters on the signal intensity of capillary electrophoresis electrospray ionization mass spectrometry in protein analysis
The soluble CTLA-4 receptor and its role in autoimmune diseases: an update
CTLA-4, initially described as a membranebound molecule, is a costimulatory receptor transducing a potent inhibitory signal. Increasing evidence shows the CTLA-4 gene to be an important susceptibility locus for autoimmune endocrinopathies and other autoimmune disorders. A soluble form of cytotoxic T-lymphocyte-associated antigen-4 (sCTLA-4) has been established and shown to possess CD80/CD86 binding activity and in vitro immunoregulatory functions. sCTLA-4 is generated by alternatively spliced mRNA. Whereas low levels of sCTLA-4 are detected in normal human serum, increased serum levels are observed in several autoimmune diseases (e.g. Graves’ disease, myasthenia gravis, systemic lupus erythematosus, type 1 diabetes, systemic sclerosis, coeliac disease, autoimmune pancreatitis and primary biliary cirrhosis). The biological significance of increased sCTLA-4 serum levels is not fully clarified yet. On the one hand, it can be envisaged that sCTLA-4 specifically inhibits early T-cell activation by blocking the interaction of CD80/CD86 with the costimulatory receptor CD28. On the other hand, higher levels of sCTLA-4 could compete for the binding of the membrane form of CTLA-4 with CD80/CD86 in the later phases of T-lymphocyte activation, causing a reduction in inhibitory signalling. This double-edged nature of sCTLA-4 to block the binding of CD28 to CD80/CD86 may result in different outcomes during the clinical course of an autoimmune disease
May increased partisanship lead to convergence of parties’ policy platforms?
Convergence, Ideology; Median voter, Two-party competition, Voting, D72,