115 research outputs found
A Markov Chain Approximation of a Segment Description of Chaos
We test a Markov chain approximation to the segment description (Li, 2007) of
chaos (and turbulence) on a tent map, the Minea system, the H\'enon map, and
the Lorenz system. For the tent map, we compute the probability transition
matrix of the Markov chain on the segments for segment time length (iterations)
. The matrix has tents corresponding to ; and is almost uniform for . As T \ra +\infty, our conjecture is
that the matrix will approach a uniform matrix (i.e. every entry is the same).
For the simple fixed point attractor in the Minea system, the Reynolds average
performs excellently and better than the maximal probability Markov chain and
segment linking. But for the strange attractors in the H\'enon map, and the
Lorenz system, the Reynolds average performs very poorly and worse than the
maximal probability Markov chain and segment linking
Importância das Células Tronco Mesenquimais no desenvolvimento do câncer de mama
La mayorĂa de las pacientes con cáncer de mama (PCM) avanzado desarrollan metástasis Ăłseas, de tipo osteolĂticas, como resultado de un desbalance entre los procesos de os-teogĂ©nesis, osteoclastogĂ©nesis y resorciĂłn Ăłsea. Nosotros encontramos en la mĂ©dula Ăłsea (MO) de las PCM avanzado (carcinoma mamario ductal infiltrante, estadĂo clĂnico III y IV, sin metástasis en MO y hueso) una disminuciĂłn de la eficiencia de clonado de las cĂ©lulas madre mesenquimales (MSC), medida como el nĂşmero de unidades formadoras de colonias fibroblásticas (CFU-F), asĂ como una disminuciĂłn en su capacidad de diferenciaciĂłn osteogĂ©nica en comparaciĂłn con las voluntarias sanas (VS). Además, observamos osteoclastogĂ©nesis espontánea en MO y sangre perifĂ©rica de las PCM, mientras que no lo hicimos en las VS. Por Ăşltimo, consideramos importante la evaluaciĂłn de la diferenciaciĂłn osteogĂ©nica de las MSC de MO y del potencial osteoclasto-gĂ©nico de los progenitores hematopoyĂ©ticos de MO y de los monocitos de sangre perifĂ©rica, como posibles factores pronĂłsticos de futuros desĂłrdenes Ăłseos que pueden favorecer la invasiĂłn de las cĂ©lulas del CM en el hueso.Most advanced breast cancer patients (BCP) develop oste-olytic bone metastasis as a result of the imbalance between osteogenesis, osteoclastogenesis and bone resorption processes.In bone marrow (BM) aspirates of untreated BCP (infiltrative ductal breast carcinoma, clinical stage III and IV, without bone and BM metastasis), a decrease in cloning efficiency of BM-mesenchymal stem cells (MSC), measured as number of colony forming unit-fibroblasts (CFU-F), and a decrease in its osteogenic differentiation capacity compared to healthy volunteers (HV) were found . Moreover, spontaneous osteoclastogenesis (SpOC) in BM and peripheral blood of BCP were observed, while SpOC was not observed in BM of HV. Finally, evaluation of the osteogenic differentiation of BM-MSC and osteoclastogenic potential of BM-hematopoi-etic progenitors as well as peripheral blood-monocytes are considered important as possible prognostic factors for future bone disorders that may favor the invasion of BC cells into bone.A maior parte das pacientes com câncer de mama (PCM) avançado desenvolve metástases Ăłsseas, de tipo osteolĂticas, como resultado de um desequilĂbrio entre os processos de os-teogĂŞnese, osteoclastogĂŞnese e ressorção Ăłssea. NĂłs encontramos na medula Ăłssea (MO) das PCM avançado (carcinoma mamário ductal infiltrante, estágĂo clĂnico III e IV, sem metástase em MO e osso) uma diminuição da eficiĂŞn-cia de clonagem das cĂ©lulas tronco mesenquimais (MSC), medida como o nĂşmero de unidades formadoras de colĂ´nias fibroblásticas (CFU-F), bem como uma diminuição em sua capacidade de diferenciação osteogĂŞnica em comparação com as voluntárias saudáveis (VS). AlĂ©m disso, observamos osteoclastogĂŞnese espontânea em MO e sangue perifĂ©rica das PCM, enquanto que nĂŁo o fizemos nas VS. Por Ăşltimo, consideramos importante a avaliação da diferenciação os-teogĂŞnica das MSC de MO e do potencial osteoclastogĂŞnico dos progenitores hematopoiĂ©ticos de MO e dos monĂłcitos de sangue perifĂ©rico, como possĂveis fatores prognĂłsticos de futuras desordens Ăłsseas que possam favorecer a invasĂŁo das cĂ©lulas do CM no osso.Fil: Fernández Vallone, Valeria Beatriz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental (i); ArgentinaFil: Labovsky, Vivian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental (i); ArgentinaFil: Martinez, Leandro Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental (i); ArgentinaFil: Chasseing, Norma Alejandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental (i); Argentin
Prognostic significance of TRAIL-R3 and CCR-2 expression in tumor epithelial cells of patients with early breast cancer
Tumor epithelial cells (TEpCs) and spindle-shaped stromal cells, not associated with the vasculature, of patients with early breast cancer express osteoprotegerin (OPG), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), receptor activator of nuclear factor kappa B ligand, stromal cell derived factor-1, interleukin-6, macrophage colony stimulating factor, chemokine (C-C motif) ligand-2 (CCL-2) and their receptors at significantly higher levels compared with non-neoplastic breast tissues. We evaluated the clinicopathological significance of these ligands and receptors in TEpC and spindle-shaped stromal cells, not associated with the vasculature, to determine their impact on prognosis of patients with early-stage breast cancer.Fil: Labovsky, Vivian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Martinez, Leandro Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Davies, Kevin Mauro. Hospital Italiano; ArgentinaFil: de Luján Calcagno, MarĂa. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; ArgentinaFil: GarcĂa Rivello, Hernán. Hospital Italiano; ArgentinaFil: Wernicke, Alejandra. Hospital Italiano; ArgentinaFil: Feldman, Leonardo. FundaciĂłn Favaloro; ArgentinaFil: Matas, Ayelen. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Giorello, MarĂa BelĂ©n. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Borzone, Francisco RaĂşl. Ministerio de Salud. Instituto Nacional del Cancer; ArgentinaFil: Choi, Hosoon. Central Texas Veterans Research Foundation; Estados UnidosFil: Howard, Scott C.. University of Tennessee; Estados UnidosFil: Chasseing, Norma Alejandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; Argentin
Biomarkers of proliferation, survival, and migration of human breast tumor cells: future perspectives
Despite recent major advance in the understanding of the mechanisms of breast cancer (BC) progression and in the development of novel therapeutic modalities, BC remains the second leading cause of mortality among women. Mortality is almost invariably due to metastasis. The different histological subtypes of BC and molecular maker expression (ER, PR and HER2) have strong prognostic and predictive values but are not enough to prevent that BC patients (BCP) develop a relapse and metastasis. So the aim of this work was the simultaneous evaluation of the expression of biomarkers related to BC progression and metastasis (OPG, TRAIL, TRAIL receptores (R) [R1, R2, R3 y R4], RANKL, RANK (RANKL-R), SDF-1, CXCR-4 (SDF-1-R), IL-6, IL-6-R, MCSF and M-CSF-R in BC cells together with the study of classic prognostic parameters (age, ER, PR, HER2, tumor size and histological grade) in BCP. Regarding the expression of these biomarkers in BC cells, the results are contradictory.Fil: Labovsky, Vivian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Martinez, Leandro Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Calcagno, MarĂa. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; ArgentinaFil: Davies, Kevin. Hospital Italiano de La Plata; ArgentinaFil: Wenicke, Alejandra. Hospital Italiano; ArgentinaFil: Garcia Rivello, Hernan. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; ArgentinaFil: Fernández Vallone, Valeria Beatriz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Chasseing, Norma Alejandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaProceedings of the AACR Special Conference on Tumor Invasion and MetastasisPhiladelphiaEstados UnidosAmerican Association for Cancer Researc
CD105 expression in cancer-associated fibroblasts: a biomarker for bone metastasis in early invasive ductal breast cancer patients
Introduction: Bone metastasis is one of the causes that mainly decrease survival in patients with advanced breast cancer. Therefore, it is essential to find prognostic markers for the occurrence of this type of metastasis during the early stage of the disease. Currently, cancer-associated fibroblasts, which represent 80% of the fibroblasts present in the tumor microenvironment, are an interesting target for studying new biomarkers and developing alternative therapies. This study evaluated the prognostic significance of the CD105 expression in cancer-associated fibroblasts in early breast cancer patients. Methods: Immunohistochemistry was used to assess CD105 expression in invasive ductal breast carcinomas (n = 342), analyzing its association with clinical and pathological characteristics. Results: High CD105 expression in cancer-associated fibroblasts was associated with an increased risk of metastatic occurrence (p = 0.0003), particularly bone metastasis (p = 0.0005). Furthermore, high CD105 expression was associated with shorter metastasis-free survival, bone metastasis-free survival, and overall survival (p = 0.0002, 0.0006, and 0.0002, respectively). CD105 expression also constituted an independent prognostic factor for metastasis-free survival, bone metastasis-free survival, and overall survival (p = 0.0003, 0.0006, and 0.0001, respectively). Discussion: The high CD105 expression in cancer-associated fibroblasts is an independent prognostic marker for bone metastasis in early breast cancer patients. Therefore, the evaluation of CD105(+) CAFs could be crucial to stratify BCPs based on their individual risk profile for the development of BM, enhancing treatment strategies and outcomes.Fil: Giorello, Maria Belen. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Martinez, Leandro Marcelo. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Borzone, Francisco RaĂşl. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Padin, MarĂa del Rosario. Hospital Italiano; ArgentinaFil: Mora, MarĂa Florencia. Hospital Italiano; ArgentinaFil: Sevic, Ina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Alaniz, Laura Daniela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Calcagno, MarĂa de Luján. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; ArgentinaFil: Garcia Rivello, Hernan Jorge. Hospital Italiano; ArgentinaFil: Wernicke, Alejandra. Hospital Italiano; ArgentinaFil: Labovsky, Vivian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Chasseing, Norma Alejandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; Argentin
Calcium Dependent CAMTA1 in Adult Stem Cell Commitment to a Myocardial Lineage
The phenotype of somatic cells has recently been found to be reversible. Direct reprogramming of one cell type into another has been achieved with transduction and over expression of exogenous defined transcription factors emphasizing their role in specifying cell fate. To discover early and novel endogenous transcription factors that may have a role in adult-derived stem cell acquisition of a cardiomyocyte phenotype, mesenchymal stem cells from human and mouse bone marrow and rat liver were co-cultured with neonatal cardiomyocytes as an in vitro cardiogenic microenvironment. Cell-cell communications develop between the two cell types as early as 24 hrs in co-culture and are required for elaboration of a myocardial phenotype in the stem cells 8-16 days later. These intercellular communications are associated with novel Ca(2+) oscillations in the stem cells that are synchronous with the Ca(2+) transients in adjacent cardiomyocytes and are detected in the stem cells as early as 24-48 hrs in co-culture. Early and significant up-regulation of Ca(2+)-dependent effectors, CAMTA1 and RCAN1 ensues before a myocardial program is activated. CAMTA1 loss-of-function minimizes the activation of the cardiac gene program in the stem cells. While the expression of RCAN1 suggests involvement of the well-characterized calcineurin-NFAT pathway as a response to a Ca(2+) signal, the CAMTA1 up-regulated expression as a response to such a signal in the stem cells was unknown. Cell-cell communications between the stem cells and adjacent cardiomyocytes induce Ca(2+) signals that activate a myocardial gene program in the stem cells via a novel and early Ca(2+)-dependent intermediate, up-regulation of CAMTA1
A high accuracy minimally invasive regularization technique for navier-stokes equations at high reynolds number
WOS: 000399308700010A method is presented, that combines the defect and deferred correction approaches to approximate solutions of Navier-Stokes equations at high Reynolds number. The method is of high accuracy in both space and time, and it allows for the usage of legacy codes a frequent requirement in the simulation of turbulent flows in complex geometries. The two-step method is considered here; to obtain a regularization that is second order accurate in space and time, the method computes a low-order accurate, stable, and computationally inexpensive approximation (Backward Euler with artificial viscosity) twice. The results are readily extendable to the higher order accuracy cases by adding more correction steps. Both the theoretical results and the numerical tests provided demonstrate that the computed solution is stable and the accuracy in both space and time is improved after the correction step. We also perform a qualitative test to demonstrate that the method is capable of capturing qualitative features of a turbulent flow, even on a very coarse mesh. (c) 2016 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 33: 814-839, 201
Approximate deconvolution with correction: A member of a new class of models for high reynolds number flows
We propose a new family of models for uid ows at high Reynolds numbers, large eddy simulation with correction (LES-C), that combines a LES approach to turbulence modeling with a defect correction methodology. We investigate, both numerically and theoretically, one of these models, based on the approximate deconvolution model (ADM). The new model, approximate deconvolution with correction, is shown to be stable and higher order accurate with respect to the filtering width. It is shown to outperform its most natural competitor, the ADM, on a variety of benchmark problems. These include the computation of errors (on a problem with known solution), a benchmark problem of finding maximal drag and lift coefficients, ow past the step, and the discussion on Taylor{Green vortex solutions
Improving Regularization Techniques for Incompressible Fluid Flows via Defect Correction
We propose and investigate two regularization models for fluid flows at higher Reynolds numbers. Both models are based on the reduced ADM regularization (RADM). One model, which we call DC-RADM (deferred correction for reduced approximate deconvolution model), aims to improve the temporal accuracy of the RADM. The second model, denoted by RADC (reduced approximate deconvolution with correction), is created with a more systemic approach. We treat the RADM regularization as a defect in approximating the true solution of the Navier-Stokes equations (NSE) and then correct for this defect, using the defect correction algorithm. Thus, the resulting RADC model can be viewed as a first member of the class that we call LESC-reduced , where one starts with a regularization that resembles a Large Eddy Simulation turbulence model and then improves it with a defect correction technique. Both models are investigated theoretically and numerically, and the RADC is shown to outperform the DC-RADM model both in terms of convergence rates and in terms of the quality of the produced solution
- …