The faintest galaxies

We investigate the nature of Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context, simultaneously accounting for various "classical" dSphs and Milky Way (MW) properties, including their Metallicity Distribution Function (MDF). The model successfully reproduces both the observed [Fe/H]-Luminosity relation and the mean MDF of UFs. According to our results UFs are the living fossils of H2-cooling minihaloes formed at z>8.5, i.e. before the end of reionization. They are the oldest and the most dark matter-dominated (M/L > 100) dSphs in the MW system, with a total mass of M = 10^(7-8) Msun. The model allows to interpret the different shape of UFs and classical dSphs MDF, along with the frequency of extremely metal-poor stars in these objects. We discuss the "missing satellites problem" by comparing the UF star formation efficiencies with those derived for minihaloes in the Via Lactea simulation.Comment: To appear in the conference proceeding: "First Stars and Galaxies: Challenges in the Next Decade" . Publisher: American Institute of Physics. Editors: V. Bromm, D. Whalen, N. Yoshid

The Classical notion of competition revisited

The paper seeks to fill a lacuna within classical economics concerning the process of market price determination in situations of market disequilibrium. To this aim, first we distinguish the classical notion of free competition from the Walrasian notion of perfect competition and we argue that the latter is beset with some theoretical difficulties alien to the former. Second, we reconstruct in some detail Smith\u2019s and Marx\u2019s views concerning market price determination and show that Marx\u2019s extensive use of metaphors and numerical examples foreshadows the modern taxonomy of buyers\u2019 market, sellers\u2019 market, and mixed strategy equilibrium in the capacity space of a standard Bertrand duopoly model. Finally, we highlight similarities and differences between the classical notion of competition and contemporary Bertrand competition models

Analysis of the Cooling Performance of a Cylindrical Hole Designed for the Suction Side of the LS89 Vane under Transitional Conditions

Thermal performance of film cooling in a transonic high-pressure vane is studied by means of two different turbulence modelling strategies: the γ-ReΘ transition model and the fully turbulent k-ω SST model. Selected test case is the LS89 vane, appropriately modified to include a cylindrical film cooling device. The MUR237 transonic configuration is selected as representative of highly loaded vanes without shocks, with transonic Mach number over the suction side. The specifically designed cooling system is based on the non-dimensional geometrical and operating conditions of the high-pressure transonic MT1 cooled vane. Transition model constants are initially tuned to match the available experimental data for the original (uncooled) configuration. Eventually, results obtained with both models are compared with each other for several jet conditions, showing non-negligible influence of turbulence modelling on flow distribution and mixing between coolant and main-flow

Continuous-wave room-temperature diamond maser

The maser, older sibling of the laser, has been confined to relative obscurity due to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this it has found application in deep-space communications and radio astronomy due to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid- state maser exploiting photo-excited triplet states in organic pentacene molecules paves the way for a new class of maser that could find applications in medicine, security and sensing, taking advantage of its sensitivity and low noise. However, to date, only pulsed operation has been observed in this system. Furthermore, organic maser molecules have poor thermal and mechanical properties, and their triplet sub-level decay rates make continuous emission challenging: alternative materials are therefore required. Therefore, inorganic materials containing spin-defects such as diamond and silicon carbide have been proposed. Here we report a continuous-wave (CW) room-temperature maser oscillator using optically pumped charged nitrogen-vacancy (NV) defect centres in diamond. This demonstration unlocks the potential of room-temperature solid-state masers for use in a new generation of microwave devices.Comment: 7 pages, 4 figure

Morphological alterations and gene and protein expression profiling of bladder tumor cells after treatment with gemcitabine.

Chemical agents used in cancer therapy are associated with cell cycle arrest, activation or deactivation of mechanisms\ud associated to DNA repair and apoptosis. However, due to the complexity of biological systems, the molecular\ud mechanisms responsible for these activities are not fully understood. Thus, studies about gene and protein expression\ud have shown promising results for understanding the mechanisms related to cellular responses and regression of cancer\ud after chemotherapy. This study aimed to evaluate the gene and protein expression profiling in bladder transitional cell\ud carcinoma (TCC) with different TP53 status after gemcitabine (1.56 μM) treatment. The RT4 (grade 1, TP53 wild\ud type), 5637 (grade 2, TP53 mutated) and T24 (grade 3, TP53 mutated) cell lines were used. PCR arrays and mass\ud spectrometry were used to analyze gene and protein expression, respectively. Morphological alterations were observed\ud using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of PCR array\ud showed that gemcitabine activity was mainly related to CDKN1A, GADD45A and SERTDA1 overexpression, and BAX\ud overexpression only in the wild type TP53 cells. Mass spectrometry demonstrated that gemcitabine modulated the protein\ud expression, especially those from genes related to apoptosis, transport of vesicles and stress response. Analyses using SEM\ud and TEM showed changes in cell morphology independently on the cell line studied. The observed decreased number of\ud microvillus suggests low contact among the cells and between cell and extracellular matrix; irregular forms might indicate\ud actin cytoskeleton deregulation; and the reduction in the amount of organelles and core size might indicate reduced\ud cellular metabolism. In conclusion, independently on TP53 status or grade of bladder tumor, gemcitabine modulated\ud genes related to the cell cycle and apoptosis, that reflected in morphological changes indicative of future cell death.FAPESPCNP

Dissecting the Pharmacodynamics and Pharmacokinetics of MSCs to Overcome Limitations in Their Clinical Translation

Recently, mesenchymal stromal stem cells (MSCs) have been proposed as therapeutic agents because of their promising preclinical features and good safety profile. However, their introduction into clinical practice has been associated with a suboptimal therapeutic profile. In this review, we address the biodistribution of MSCs in preclinical studies with a focus on the current understanding of the pharmacodynamics (PD) and pharmacokinetics (PK) of MSCs as key aspects to overcome unsatisfactory clinical benefits of MSC application. Beginning with evidence of MSC biodistribution and highlighting PK and PD factors, a new PK-PD model is also proposed. According to this theory, MSCs and their released factors are key players in PK, and the efficacy biomarkers are considered relevant for PD in more predictive preclinical investigations. Accounting for the PK-PD relationship in MSC translational research and proposing new models combined with better biodistribution studies could allow realization of the promise of more robust MSC clinical translation. The number of clinical trials based on MSCs that are publicly available exceeds 800; however, data regarding MSC pharmacodynamics (PD), pharmacokinetics (PK), and biodistribution are still scarce. For this reason, we dissected the PD and PK properties of MSCs, presenting factors that may influence MSC-based PK studies to then conceive a new PK-PD model that would support better and more robust MSC clinical translation

The atrophic effect of 1,25(Oh)2 vitamin d3 (calcitriol) on c2c12 myotubes depends on oxidative stress

Dysfunctional mitochondrial metabolism has been linked to skeletal muscle loss in several physio-pathological states. Although it has been reported that vitamin D (VD) supports cellular redox homeostasis by maintaining normal mitochondrial functions, and VD deficiency often occurs in conditions associated with skeletal muscle loss, the efficacy of VD supplementation to overcome muscle wasting is debated. Investigations on the direct effects of VD metabolites on skeletal muscle using C2C12 myotubes have revealed an unexpected pro-atrophic activity of calcitriol (1,25VD), while its upstream metabolites cholecalciferol (VD3) and calcidiol (25VD) have anti-atrophic effects. Here, we investigated if the atrophic effects of 1,25VD on myotubes depend on its activity on mitochondrial metabolism. The impact of 1,25VD and its upstream metabolites VD3 and 25VD on mitochondria dynamics and the activity of C2C12 myotubes was evaluated by measuring mitochondrial content, architecture, metabolism, and reactive oxygen species (ROS) production. We found that 1,25VD induces atrophy through protein kinase C (PKC)-mediated ROS production, mainly of extramito-chondrial origin. Consistent with this, cotreatment with the antioxidant N-acetylcysteine (NAC), but not with the mitochondria-specific antioxidant mitoTEMPO, was sufficient to blunt the atrophic activity of 1,25VD. In contrast, VD3 and 25VD have antioxidant properties, suggesting that the efficacy of VD supplementation might result from the balance between atrophic pro-oxidant (1,25VD) and protective antioxidant (VD3 and 25VD) metabolites

CHO cell adhesion on modified surfaces of different materials.

Epithelial cells are mainly responsible for the formation of tissues that cover the external and internal surfaces of organs like skin, lining of the lungs and intestines. The cells must adhere to substrates and to each other in compliance with certain stimulus. In this way, adhesion properties can be regulated by the cell which simultaneously senses the chemical and mechanical properties of its environment. Their adhesion and growth on biomaterials depends on substrate properties such as surface wettability, topography and chemistry. The aim of this study is to investigate cell-surface interactions using several materials and different surfaces

Efeito da rotação de culturas sobre a ocorrência de Sternechus subsignatus em soja.

bitstream/item/133900/1/ID11080-1990-1991sojaresultados-p109-110.pdfTrabalhos apresentados na XIX Reunião de Pesquisa de Soja da Região Sul, Pelotas, 1991

Avaliação da eficiência de inseticidas no controle da lagarta da soja (Anticarsia gemmatalis Huebner, 1818) na cultura da soja.

bitstream/item/133980/1/ID43421-1990-1991sojaresultados-p119-122.pdfTrabalhos apresentados na XIX Reunião de Pesquisa de Soja da Região Sul, Pelotas, 1991