234 research outputs found
Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition
Great emphasis is placed on the development of integrated approaches for the
synthesis and the characterization of ad hoc nanostructured platforms, to be
used as templates with controlled morphology and chemical properties for the
investigation of specific phenomena of great relevance for technological
applications in interdisciplinary fields such as biotechnology, medicine and
advanced materials. Here we discuss the crucial role and the advantages of thin
film deposition strategies based on cluster-assembling from supersonic cluster
beams. We select cluster-assembled nanostructured titania (ns-TiO2) as a case
study to demonstrate that accurate control over morphological parameters can be
routinely achieved, and consequently over several relevant interfacial
properties and phenomena, like surface charging in a liquid electrolyte, and
proteins and nanoparticles adsorption
Os efeitos do e-commerce na produtividade das firmas comerciais no Brasil
With the emergence of the internet, the e-commerce grows on daily basis, in Brazil and in the world. In 2007 was still very low by Brazilian trade firms, even considering only firms with 20 or more employees. Only 855 firms adopted this practice in a total of 38.339 firms. The set up of this kind of innovation allows reduction of transaction costs, but, in the other hand, it demands logistics and information technology upgrades, and also qualified personnel. Theses improvements could dealt by public policies. The current studied developed a pioneering evaluation of the effects of e-commerce in the Brazilian economy. More specically, the effects of adoption of this kind of innovation in the productivity of wholesale and retail firms were analyzed. The studied followed an econometric methodology that tries to control the possible effects of endogeneity and self-selection bias. In other words, it tries to control the possible bias caused by the fact that the choice of adoption or not e-commerce might be influenced by the productivity. The study used microdata of the 2007 Annual Trade Survey (Pesquisa Annual de Comércio), by the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografica e EstatÃstica, the Brazilian nacional statistics agency). The methodology was used by Bertschek, Fryges and Kaiser (2004) to evaluate the impact of business-to-business e-commerce on the productivity of German firms
Upregulation of SOCS-1 by Nutlin-3 in acute myeloid leukemia cells but not in primary normal cells
OBJECTIVE: It has been shown that SOCS-1 plays an important role in the proper control of cytokine/growth factor responses and acts as a tumor suppressor in acute myeloid leukemias. Therefore, the objective of the present study was to evaluate the in vitro effect of treatment with Nutlin-3, a small molecule inhibitor of the MDM2/p53 interaction, on the expression of the suppressor of cytokine signaling 1 in primary acute myeloid leukemia cells and in myeloid cell lines with differential p53 status. METHOD: The expression of the suppressor of cytokine signaling 1 was quantitatively analyzed by real-time PCR in myeloid p53wild-type (OCI and MOLM) and p53null HL-60, leukemic cell lines, in patient-derived acute myeloid leukemia blasts, and in primary normal cell types, such as macrophages, endothelial cells, and bone marrow mesenchymal stem cells. The p53-dependence of the suppressor of cytokine signaling 1 upregulation that is induced by Nutlin-3 was analyzed in experiments performed using siRNA for p53, while the functional upregulation of the suppressor of cytokine signaling 1 was analyzed by assessing the levels of phosphorylated STAT-3. RESULTS: Nutlin-3 significantly upregulated the transcription of the suppressor of cytokine signaling 1 in p53wild-type OCI and MOLM but not in p53deleted p53null HL60, myeloid leukemic cell lines, as well as in primary acute myeloid leukemia blasts. Conversely, and somewhat unexpectedly, Nutlin-3 did not modulate the suppressor of cytokine signaling 1 expression in primary normal macrophages, endothelial cells, and bone marrow mesenchymal stem cells. The p53-dependent upregulation of the suppressor of cytokine signaling 1 by Nutlin-3 was associated with the downregulation of phosphorylated STAT-3, a major molecular target of the suppressor of cytokine signaling 1. CONCLUSION: Overall, our data suggest a potential role for the suppressor of cytokine signaling 1 as a therapeutic target of Nutlin-3 in p53 wild-type acute myeloid leukemias
Vitamin D in Prevention of Autoimmune Diseases
Vitamin D is essential for the regulation of the immune system. In recent years, the role of vitamin D in the control of several autoimmune conditions such as inflammatory bowel disease (IBD), celiac disease, type 1 diabetes mellitus (T1DM), and others has been investigated. The aim of this review was to define the level of knowledge on vitamin D's role in these disorders, as well as the preventive and therapeutic role of vitamin D supplementation. Relevant studies published over the last 20 years were identified via a PubMed/Medline (http://www.ncbi.nlm.nih.gov/pubmed/) search using the keywords: vitamin D, autoimmune disease, and prevention. Vitamin D deficiency or impaired function of the enzymes necessary for its activity has been shown to affect the onset and severity of the autoimmune diseases examined. Vitamin D supplementation appears useful in the support therapy of IBD. Its role in celiac disease, autoimmune hepatitis, T1DM, and autoimmune thyroiditis is unclear. In conclusion, further studies are needed to define whether vitamin D is a cause or a result of the most common autoimmune, extra-skeletal diseases, such as IBD. Vitamin D should be provided to all newborns during their first year of life. Afterwards, the vitamin D supplementation regimen should be tailored to the presence of risk factors for vitamin D deficiency and/or specific disease
Fractal analysis of sampled profiles: Systematic study
A quantitative evaluation of the influence of sampling on the numerical fractal analysis of experimental profiles is of critical importance. Although this aspect has been widely recognized, a systematic analysis of the sampling influence is still lacking. Here we present the results of a systematic analysis of synthetic self-affine profiles in order to clarify the consequences of the application of a poor sampling (up to 1000 points) typical of scanning probe microscopy for the characterization of real interfaces and surfaces. We interpret our results in terms of a deviation and a dispersion of the measured exponent with respect to the "true" one. Both the deviation and the dispersion have always been disregarded in the experimental literature, and this can be very misleading if results obtained from poorly sampled images are presented. We provide reasonable arguments to assess the universality of these effects and propose an empirical method to take them into account. We show that it is possible to correct the deviation of the measured Hurst exponent from the "true" one and give a reasonable estimate of the dispersion error. The last estimate is particularly important in the experimental results since it is an intrinsic error that depends only on the number of sampling points and can easily overwhelm the statistical error. Finally, we test our empirical method calculating the Hurst exponent for the well-known 1 + 1 dimensional directed percolation profiles, with a 512-point sampling
Pensemos diverso: pensar, discutir y construir identidades generizadas con otres
El proyecto #PensemosDiverso aborda la construcción de sentidos que ponen en tensión las matrices de pensamiento patriarcales, sexistas y machistas. Nace el 2018 como un proyecto institucional, académico-comunicacional, que trabaja para visibilizar problemáticas de género y diversidades. La actual propuesta se enmarca en la convocatoria Universidad, Cultura y Territorio 2021 y constituye una oportunidad para dialogar con diferentes organizaciones sociales que problematizan cuestiones relacionadas a género y la distribución desigual del poder entre las personas en razón de su condición sexual o identidad de género.Universidad Nacional de La Plat
- …