2,610 research outputs found
Large Momenta Fluctuations Of Charm Quarks In The Quark-Gluon Plasma
We show that large fluctuations of D mesons kinetic energy (or momentum)
distributions might be a signature of a phase transition to the quark gluon
plasma (QGP). In particular, a jump in the variance of the momenta or kinetic
energy, as a function of a control parameter (temperature or Fermi energy at
finite baryon densities) might be a signature for a first order phase
transition to the QGP. This behaviour is completely consistent with the order
parameter defined for a system of interacting quarks at zero temperature and
finite baryon densities which shows a jump in correspondance to a first order
phase transition to the QGP. The shows exactly the same behavior of
the order parameter and of the variance of the D mesons. We discuss
implications for relativistic heavy ion collisions within the framework of a
transport model and possible hints for experimental data.Comment: 4 pages 3 figure
3D Porous Architecture of Stacks of β-TCP Granules Compared with That of Trabecular Bone: A microCT, Vector Analysis, and Compression Study
The 3D arrangement of porous granular biomaterials usable to fill bone defects has received little study. Granular biomaterials occupy 3D space when packed together in a manner that creates a porosity suitable for the invasion of vascular and bone cells. Granules of beta-tricalcium phosphate (β-TCP) were prepared with either 12.5 or 25 g of β-TCP powder in the same volume of slurry. When the granules were placed in a test tube, this produced 3D stacks with a high (HP) or low porosity (LP), respectively. Stacks of granules mimic the filling of a bone defect by a surgeon. The aim of this study was to compare the porosity of stacks of β-TCP granules with that of cores of trabecular bone. Biomechanical compression tests were done on the granules stacks. Bone cylinders were prepared from calf tibia plateau, constituted high-density (HD) blocks. Low-density (LD) blocks were harvested from aged cadaver tibias. Microcomputed tomography was used on the β-TCP granule stacks and the trabecular bone cores to determine porosity and specific surface. A vector-projection algorithm was used to image porosity employing a frontal plane image, which was constructed line by line from all images of a microCT stack. Stacks of HP granules had porosity (75.3 ± 0.4%) and fractal lacunarity (0.043 ± 0.007) intermediate between that of HD (respectively 69.1 ± 6.4%, p < 0.05 and 0.087 ± 0.045, p < 0.05) and LD bones (respectively 88.8 ± 1.57% and 0.037 ± 0.014), but exhibited a higher surface density (5.56 ± 0.11 mm(2)/mm(3) vs. 2.06 ± 0.26 for LD, p < 0.05). LP granular arrangements created large pores coexisting with dense areas of material. Frontal plane analysis evidenced a more regular arrangement of β-TCP granules than bone trabecule. Stacks of HP granules represent a scaffold that resembles trabecular bone in its porous microarchitecture
Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis): whole-body MR findings in two siblings with different subcutaneous nodules distribution
Abstract: Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis) is a rare, progressive, autosomal recessive disorder whose main hallmark is the deposition of amorphous hyaline material in soft tissues, with an evolutionary course and health impairment. It may present involvement of subcutaneous or periskeletal soft tissue, or may develop as a visceral infiltration entity with poor prognosis. Very few radiological data about this inherited condition have been reported, due to the extreme rarity of disease. We herein present a case of two siblings, affected by different severity of the disease, with different clinical features. They were examined by whole-body MR (WBMR) in order to assess different lesions localization, to rule out any visceral involvement and any other associated anomalies and to define patients\ue2\u80\u99 management
Characterization of polyaniline-detonation nanodiamond nanocomposite fibers by atomic force microscopy based technique
Polyaniline (PANI) fibers were synthesized in presence of detonantion nanodiamond (DND) particles by precipitation polymerization technique. Morphological, electrical and mechanical characterizations of the obtained PANI/DND nanocomposited have been performed by different either standard or advanced atomic force microscopy (AFM) based techniques. Morphological characterization by tapping mode AFM supplied information about the structure of fibers and ribbons forming the PANI/DND network. An AFM based technique that takes advantage of an experimental configuration specifically devised for the purpose was used to assess the electrical properties of the fibers, in particular to verify their conductivity. Finally, mechanical characterization was carried out synergically using two different and recently proposed AFM based techniques, one based on AFM tapping mode and the other requiring AFM contact mode, which probed the nanocomposited nature of PANI/DND fiber sample down to different depths. © 2013 Elsevier Ltd. All rights reserved
HDAC inhibition potentiates immunotherapy in triple negative breast cancer.
Triple-negative breast cancer (TNBC) represents a more aggressive and difficult subtype of breast cancer where responses to chemotherapy occur, but toxicity is significant and resistance often follows. Immunotherapy has shown promising results in various types of cancer, including breast cancer. Here, we investigated a new combination strategy where histone deacetylase inhibitors (HDACi) are applied with immune checkpoint inhibitors to improve immunotherapy responses in TNBC. Testing different epigenetic modifiers, we focused on the mechanisms underlying HDACi as priming modulators of immunotherapy. Tumor cells were co-cultured with human peripheral blood mononuclear cells (PBMCs) and flow cytometric immunophenotyping was performed to define the role of epigenetic priming in promoting tumor antigen presentation and immune cell activation. We found that HDACi up-regulate PD-L1 mRNA and protein expression in a time-dependent manner in TNBC cells, but not in hormone responsive cells. Focusing on TNBC, HDACi up-regulated PD-L1 and HLA-DR on tumor cells when co-cultured with PBMCs and down-regulated CD4+ Foxp3+ Treg in vitro. HDACi significantly enhanced the in vivo response to PD-1/CTLA-4 blockade in the triple-negative 4T1 breast cancer mouse model, the only currently available experimental system with functional resemblance to human TNBC. This resulted in a significant decrease in tumor growth and increased survival, associated with increased T cell tumor infiltration and a reduction in CD4+ Foxp3+ T cells in the tumor microenvironment. Overall, our results suggest a novel role for HDAC inhibition in combination with immune checkpoint inhibitors and identify a promising therapeutic strategy, supporting its further clinical evaluation for TNBC treatment
Análisis de los desechos lĂticos del sitio Amigo Oeste (meseta de Somuncurá, provincia de RĂo Negro): Aportes para el conocimiento de los procesos de producciĂłn lĂtica
This work represents an improvement in the understanding of lithic artifact production processes at the Amigo Oeste site, located on the Somuncurá plateau (RĂo Negro, Argentina). This site has a surface assemblage characterized by several Fishtails points, which link its chronology to the Pleistocene-Holocene transition during the early settlement of the area. Based on the techno-morphological study of the debitage retrieved in systematic transect survey, we propose that knapping and final sharpening of tools were the main activities that took place in this site. This new information reaffirms the idea that Amigo Oeste was a meeting place of hunter-gatherer societies where replacement, re-equipment and final production of Fishtail points were carried out.Este trabajo constituye un avance en el conocimiento de los procesos de producciĂłn de artefactos lĂticos que tuvieron lugar en el sitio Amigo Oeste, ubicado en la meseta de Somuncurá (RĂo Negro, Argentina). Este sitio presenta un conjunto superficial caracterizado por numerosas Puntas Cola de Pescado (PCP), que permiten anclar su cronologĂa en la transiciĂłn Pleistoceno-Holoceno, lo que da cuenta del poblamiento inicial del área. A partir del estudio tecno-morfolĂłgico de los desechos recuperados durante el relevamiento sistemático por transectas, se propone que en el sitio se desarrollaron principalmente actividades de talla y de formatizaciĂłn final de instrumentos. La nueva informaciĂłn reafirma la idea de que Amigo Oeste fue un lugar donde se llevĂł a cabo el recambio, requipamiento y/o la producciĂłn final de Puntas Cola de Pescado
Three-dimensional arrangement of β-tricalcium phosphate granules evaluated by microcomputed tomography and fractal analysis.
The macrophysical properties of granular biomaterials used to fill bone defects have rarely been considered. Granules of a given biomaterial occupy three-dimensional (3-D) space when packed together and create a macroporosity suitable for the invasion of vascular and bone cells. Granules of β-tricalcium phosphate were prepared using polyurethane foam technology and increasing the amount of material powder in the slurry (10, 11, 15, 18, 21 and 25g). After sintering, granules of 1000-2000μm were prepared by sieving. They were analyzed morphologically by scanning electron microscopy and placed in polyethylene test tubes to produce 3-D scaffolds. Microcomputed tomography (microCT) was used to image the scaffolds and to determine porosity and fractal dimension in three dimensions. Two-dimensional sections of the microCT models were binarized and used to compute classical morphometric parameters describing porosity (interconnectivity index, strut analysis and star volumes) and fractal dimensions. In addition, two newly important fractal parameters (lacunarity and succolarity) were measured. Compression analysis of the stacks of granules was done. Porosity decreased as the amount of material in the slurry increased but non-linear relationships were observed between microarchitectural parameters describing the pores and porosity. Lacunarity increased in the series of granules but succolarity (reflecting the penetration of a fluid) was maximal in the 15-18g groups and decreased noticeably in the 25g group. The 3-D arrangement of biomaterial granules studied by these new fractal techniques allows the optimal formulation to be derived based on the lowest amount of material, suitable mechanical resistance during crushing and the creation of large interconnected pores
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