5,664 research outputs found
Role of ATM signaling in PALB2-dependent DNA damage responses
Poster presentation - Theme 1: Cell biologyMutations of the PALB2 gene lead to a number of hereditary cancer-predisposing syndromes, including Fanconi anemia and hereditary breast and ovarian cancer syndrome. Originally identified as a core DNA repair factor, emerging evidence now implicates PALB2 in cell cycle checkpoint control, DNA replication, oxidative stress regulation and transcription, highlighting the multi-functionality of the tumor suppressor. Notably, mechanistically how its expanding repertoire of functions are orchestrated remains ...postprin
Searches for Long Lived Neutral Particles
An intriguing possibility for TeV scale physics is the existence of neutral
long lived particles (LOLIPs) that subsequently decay into SM states. Such
particles are many cases indistinguishable from missing transverse energy (MET)
at colliders. We propose new methods to search for these particles using
neutrino telescopes. We study their detection prospects, assuming production
either at the LHC or through dark matter (DM) annihilations in the Sun and the
Earth. We find that the sensitivity for LOLIPs produced at the LHC is limited
by luminosity and detection energy thresholds. On the other hand, in the case
of DM annihilation into LOLIPs, the sensitivity of neutrino telescopes is
promising and may extend beyond the reach of upcoming direct detection
experiments. In the context of low scale hidden sectors weakly coupled to the
SM, such indirect searches allow to probe couplings as small as 10^-15.Comment: 22 pages, 6 figure
Effects of Thyroxine Exposure on Osteogenesis in Mouse Calvarial Pre-Osteoblasts
The incidence of craniosynostosis is one in every 1,800-2500 births. The gene-environment model proposes that if a genetic predisposition is coupled with environmental exposures, the effects can be multiplicative resulting in severely abnormal phenotypes. At present, very little is known about the role of gene-environment interactions in modulating craniosynostosis phenotypes, but prior evidence suggests a role for endocrine factors. Here we provide a report of the effects of thyroid hormone exposure on murine calvaria cells. Murine derived calvaria cells were exposed to critical doses of pharmaceutical thyroxine and analyzed after 3 and 7 days of treatment. Endpoint assays were designed to determine the effects of the hormone exposure on markers of osteogenesis and included, proliferation assay, quantitative ALP activity assay, targeted qPCR for mRNA expression of Runx2, Alp, Ocn, and Twist1, genechip array for 28,853 targets, and targeted osteogenic microarray with qPCR confirmations. Exposure to thyroxine stimulated the cells to express ALP in a dose dependent manner. There were no patterns of difference observed for proliferation. Targeted RNA expression data confirmed expression increases for Alp and Ocn at 7 days in culture. The genechip array suggests substantive expression differences for 46 gene targets and the targeted osteogenesis microarray indicated 23 targets with substantive differences. 11 gene targets were chosen for qPCR confirmation because of their known association with bone or craniosynostosis (Col2a1, Dmp1, Fgf1, 2, Igf1, Mmp9, Phex, Tnf, Htra1, Por, and Dcn). We confirmed substantive increases in mRNA for Phex, FGF1, 2, Tnf, Dmp1, Htra1, Por, Igf1 and Mmp9, and substantive decreases for Dcn. It appears thyroid hormone may exert its effects through increasing osteogenesis. Targets isolated suggest a possible interaction for those gene products associated with calvarial suture growth and homeostasis as well as craniosynostosis. © 2013 Cray et al
Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry
We investigate supersymmetric scenarios in which neutrino masses are
generated by effective d=6 operators in the Kahler potential, rather than by
the standard d=5 superpotential operator. First, we discuss some general
features of such effective operators, also including SUSY-breaking insertions,
and compute the relevant renormalization group equations. Contributions to
neutrino masses arise at low energy both at the tree level and through finite
threshold corrections. In the second part we present simple explicit
realizations in which those Kahler operators arise by integrating out heavy
SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge,
depending on the mechanism and the scale of SUSY-breaking mediation. In
particular, we propose an appealing and economical picture in which the heavy
seesaw mediators are also messengers of SUSY breaking. In this case, strong
correlations exist among neutrino parameters, sparticle and Higgs masses, as
well as lepton flavour violating processes. Hence, this scenario can be tested
at high-energy colliders, such as the LHC, and at lower energy experiments that
measure neutrino parameters or search for rare lepton decays.Comment: LaTeX, 34 pages; some corrections in Section
Identification and characterization of a novel non-structural protein of bluetongue virus
Bluetongue virus (BTV) is the causative agent of a major disease of livestock (bluetongue). For over two decades, it has been widely accepted that the 10 segments of the dsRNA genome of BTV encode for 7 structural and 3 non-structural proteins. The non-structural proteins (NS1, NS2, NS3/NS3a) play different key roles during the viral replication cycle. In this study we show that BTV expresses a fourth non-structural protein (that we designated NS4) encoded by an open reading frame in segment 9 overlapping the open reading frame encoding VP6. NS4 is 77–79 amino acid residues in length and highly conserved among several BTV serotypes/strains. NS4 was expressed early post-infection and localized in the nucleoli of BTV infected cells. By reverse genetics, we showed that NS4 is dispensable for BTV replication in vitro, both in mammalian and insect cells, and does not affect viral virulence in murine models of bluetongue infection. Interestingly, NS4 conferred a replication advantage to BTV-8, but not to BTV-1, in cells in an interferon (IFN)-induced antiviral state. However, the BTV-1 NS4 conferred a replication advantage both to a BTV-8 reassortant containing the entire segment 9 of BTV-1 and to a BTV-8 mutant with the NS4 identical to the homologous BTV-1 protein. Collectively, this study suggests that NS4 plays an important role in virus-host interaction and is one of the mechanisms played, at least by BTV-8, to counteract the antiviral response of the host. In addition, the distinct nucleolar localization of NS4, being expressed by a virus that replicates exclusively in the cytoplasm, offers new avenues to investigate the multiple roles played by the nucleolus in the biology of the cell
A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR
Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed
Effects of cyclooxygenase-1 and -2 gene disruption on Helicobacter pylori-induced gastric inflammation
Background. Cyclooxygenases (COXs) play important roles in inflammation and carcinogenesis. The present study aimed to determine the effects of COX-1 and COX-2 gene disruption on Helicobacter pylori-induced gastric inflammation. Methods. Wild-type (WT), COX-1 and COX-2 heterozygous (COX-1 +/- and COX-2 +/-), and homozygous COX-deficient (COX-1 -/- and COX-2 -/-) mice were inoculated with H. pylori strain TN2 and killed after 24 weeks of infection. Uninfected WT and COX-deficient mice were used as controls. Levels of gastric mucosal inflammation, epithelial cell proliferation and apoptosis, and cytokine expression were determined. Results. COX deficiency facilitated H. pylori-induced gastritis. In the presence of H. pylori infection, apoptosis was increased in both WT and COX-deficient mice, whereas cell proliferation was increased in WT and COX-1-deficient, but not in COX-2-deficient, mice. Tumor necrosis factor (TNF)-α and interleukin-10 mRNA expression was elevated in H. pylori-infected mice, but only TNF-α mRNA expression was further increased by COX deficiency. Prostaglandin E 2 levels were increased in infected WT and COX-2-deficient mice but were at very low levels in infected COX-1-deficient mice. Leukotriene (LT) B 4 and LTC 4 levels were increased to a similar extent in infected WT and COX-deficient mice. Conclusions. COX deficiency enhances H. pylori-induced gastritis, probably via TNF-α expression. COX-2, but not COX-1, deficiency suppresses H. pylori-induced cell proliferation. © 2006 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio
The gravitino coupling to broken gauge theories applied to the MSSM
We consider gravitino couplings in theories with broken gauge symmetries. In
particular, we compute the single gravitino production cross section in W+ W-
fusion processes. Despite recent claims to the contrary, we show that this
process is always subdominant to gluon fusion processes in the high energy
limit. The full calculation is performed numerically; however, we give analytic
expressions for the cross section in the supersymmetric and electroweak limits.
We also confirm these results with the use of the effective theory of goldstino
interactions.Comment: 26 pages, 4 figure
Phytostabilization of metals in mine soils using Brassica juncea in combination with organic amendments
Background and aims The high metal bioavailability and the poor conditions of mine soils yield a low plant biomass, limiting the application of phytoremediation techniques. A greenhouse experiment was performed to evaluate the effects of organic amendments on metal stabilization and the potential of Brassica juncea L. for phytostabilization in mine soils. Methods Plants were grown in pots filled with soils collected from two mine sites located in Central Spain mixed with 0, 30 and 60 tha?1 of pine bark compost and horse- and sheep-manure compost. Plant biomass and metal concentrations in roots and shoots were measured. Metal bioavailability was assessed using a rhizosphere-based method (rhizo), which consists of a mixture of low-molecular-weight organic acids to simulate root exudates. Results Manure reduced metal concentrations in shoots (10?50 % reduction of Cu and 40?80 % of Zn in comparison with non-amended soils), bioconcentration factor (10?50 % of Cu and 40?80 % of Zn) and metal bioavailability in soil (40?50 % of Cu and 10?30 % of Zn) due to the high pH and the contribution of organic matter. Manure improved soil fertility and was also able to increase plant biomass (5?20 times in shoots and 3?30 times in roots), which resulted in a greater amount of metals removed from soil and accumulated in roots (increase of 2?7 times of Cu and Zn). Plants grown in pine bark treatments and in non-amended soils showed a limited biomass and high metal concentrations in shoots. Conclusions The addition of manure could be effective for the stabilization of metals and for enhancing the phytostabilization ability of B. juncea in mine soils. In this study, this species resulted to be a potential candidate for phytostabilization in combination with manure, differing from previous results, in which B. juncea had been recognized as a phytoextraction plant
Sanitation of blackwater via sequential wetland and electrochemical treatment
The discharge of untreated septage is a major health hazard in countries that lack sewer systems and centralized sewage treatment. Small-scale, point-source treatment units are needed for water treatment and disinfection due to the distributed nature of this discharge, i.e., from single households or community toilets. In this study, a high-rate-wetland coupled with an electrochemical system was developed and demonstrated to treat septage at full scale. The full-scale wetland on average removed 79 +/- 2% chemical oxygen demand (COD), 30 +/- 5% total Kjeldahl nitrogen (TKN), 58 +/- 4% total ammoniacal nitrogen (TAN), and 78 +/- 4% orthophosphate. Pathogens such as coliforms were not fully removed after passage through the wetland. Therefore, the wetland effluent was subsequently treated with an electrochemical cell with a cation exchange membrane where the effluent first passed through the anodic chamber. This lead to in situ chlorine or other oxidant production under acidifying conditions. Upon a residence time of at least 6 h of this anodic effluent in a buffer tank, the fluid was sent through the cathodic chamber where pH neutralization occurred. Overall, the combined system removed 89 +/- 1% COD, 36 +/- 5% TKN, 70 +/- 2% TAN, and 87 +/- 2% ortho-phosphate. An average 5-log unit reduction in coliform was observed. The energy input for the integrated system was on average 16 +/- 3 kWh/m(3), and 11 kWh/m(3) under optimal conditions. Further research is required to optimize the system in terms of stability and energy consumption
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