Supersymmetric top and bottom squark production at hadron colliders

The scalar partners of top and bottom quarks are expected to be the lightest squarks in supersymmetric theories, with potentially large cross sections at hadron colliders. We present predictions for the production of top and bottom squarks at the Tevatron and the LHC, including next-to-leading order corrections in supersymmetric QCD and the resummation of soft gluon emission at next-to-leading-logarithmic accuracy. We discuss the impact of the higher-order corrections on total cross sections and transverse-momentum distributions, and provide an estimate of the theoretical uncertainty due to scale variation and the parton distribution functions.Comment: 29 pages, 6 figure

CD133 Positive Embryonal Rhabdomyosarcoma Stem-Like Cell Population Is Enriched in Rhabdospheres

Cancer stem cells (CSCs) have been identified in a number of solid tumors, but not yet in rhabdomyosarcoma (RMS), the most frequently occurring soft tissue tumor in childhood. Hence, the aim of this study was to identify and characterize a CSC population in RMS using a functional approach. We found that embryonal rhabdomyosarcoma (eRMS) cell lines can form rhabdomyosarcoma spheres (short rhabdospheres) in stem cell medium containing defined growth factors over several passages. Using an orthotopic xenograft model, we demonstrate that a 100 fold less sphere cells result in faster tumor growth compared to the adherent population suggesting that CSCs were enriched in the sphere population. Furthermore, stem cell genes such as oct4, nanog, c-myc, pax3 and sox2 are significantly upregulated in rhabdospheres which can be differentiated into multiple lineages such as adipocytes, myocytes and neuronal cells. Surprisingly, gene expression profiles indicate that rhabdospheres show more similarities with neuronal than with hematopoietic or mesenchymal stem cells. Analysis of these profiles identified the known CSC marker CD133 as one of the genes upregulated in rhabdospheres, both on RNA and protein levels. CD133+ sorted cells were subsequently shown to be more tumorigenic and more resistant to commonly used chemotherapeutics. Using a tissue microarray (TMA) of eRMS patients, we found that high expression of CD133 correlates with poor overall survival. Hence, CD133 could be a prognostic marker for eRMS. These experiments indicate that a CD133+ CSC population can be enriched from eRMS which might help to develop novel targeted therapies against this pediatric tumor

Sporadic clear cell renal cell carcinoma but not the papillary type is characterized by severely reduced frequency of primary cilia

Renal cysts and clear cell renal cell carcinoma are common clinical manifestations of people with germ-line mutations of the von Hippel-Lindau tumor suppressor gene, VHL. Recent cell biological evidence suggests that the VHL gene product, pVHL, functions to maintain the primary cilium, a microtubule-based antenna-like structure whose functional integrity is believed to have an important role in cell-cycle control. As VHL mutations are common in sporadic clear cell renal cell carcinoma, but not papillary renal cell carcinoma, we asked whether there is an association between VHL status and primary cilia in vivo. VHL status was assessed in 20 cases of clear cell renal cell carcinoma and 9 cases of papillary renal cell carcinoma by DNA sequencing and by immunohistochemical staining for the hypoxia-inducible factor-alpha target gene products CA9 and GLUT-1. Of 20, 18 clear cell renal cell carcinomas, but only 1 of 9 papillary renal cell carcinomas, displayed evidence of VHL inactivation. In clear cell renal cell carcinoma the frequency of ciliated tumor cells ranged from 0 to 22% (median value 7.8+/-6.0%), whereas cilia frequency was significantly higher (P<0.0001) in papillary renal cell carcinoma (range 12-83%, median value 43.3+/-21.3%). There was no correlation between Ki-67 staining and cilia frequency, suggesting that the observed differences between the tumor types in cilia frequency are not accounted for by differences in cellular proliferation rates and that primary cilia degeneration in sporadic clear cell renal cell carcinoma depends on VHL inactivation. We propose that the different ciliation status of clear cell and papillary renal cell carcinoma may contribute, at least in part, to the different biological behaviors of these tumor types

Utilização dos ácidos graxos no tratamento de feridas: uma revisão integrativa da literatura nacional

Os objetivos deste estudo foram caracterizar a produção científica nacional da utilização tópica de ácidos graxos no tratamento de feridas e descrever os efeitos da sua ação nesse processo. Trata-se de uma revisão integrativa da literatura indexada nas bases de dados LILACS e BEDEnf. A coleta de dados ocorreu no mês de dezembro de 2010, com descritores de assuntos controlados e sem delimitação de período de busca. A amostra constitui-se de 09 artigos, sendo, a maioria conduzida em modelos animais e utilizando diferentes composições de ácidos graxos. Diante da escassez de estudos clínicos randomizados controlados em humanos e as limitações desta revisão, não se pôde generalizar, na prática clínica, que os ácidos graxos essenciais influenciam o processo de cicatrização positivamente ou possuem ação antimicrobiana. Assim, há necessidade de realização de pesquisas com maior rigor metodológico comparando as diferentes fórmulas disponíveis contendo ácidos graxos e sua influência no processo cicatricial

NNLL resummation for squark-antisquark pair production at the LHC

We consider the resummation of soft gluon emission for squark-antisquark pair-production at the LHC at next-to-next-to-leading-logarithmic (NNLL) accuracy in the framework of the minimal supersymmetric standard model. We present the analytical ingredients needed for the calculation and provide numerical predictions for the LHC at centre-of-mass energies of 7 and 14 TeV. We find a significant reduction in the scale uncertainty and a considerable increase in the prediction of the total cross section. Compared to the next-to-leading order prediction, the corrections increase the cross section by up to 30% for 1.5 TeV squarks at a centre-of-mass energy of 7 TeV.Comment: 22 pages, 5 figure

Species diversification – which species should we use?

Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV. visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials. The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems. as established by test beam measurements and simulation studies. is described. © 2008 IOP Publishing Ltd and SISSA