Analysis of Coal Combustion in Oxy-fuel Conditions through Pulsed Feeding Experiments in an Entrained Flow Reactor

Coal combustion is investigated in both air and oxy-fuel conditions in a pilot-scale entrained flow reactor able to provide high temperatures, heating rates and residence times. Measurements are carried out with different levels of complexity and are aimed at: assessing the thermal field inside the reactor; evaluating conversions of devolatilization or char combustion tests; identifying phenomena such as volatiles ignition and measuring the ignition delay time. Computational Fluid Dynamics was also used in order to provide a better understanding of the experimental evidences. Among the results, the ignition delay time was found to be larger in oxy-fuel conditions than in air, mainly because of the larger specific heat of the oxy-fuel environment. The proposed investigation may help the qualification of advanced experimental apparatus as entrained flow reactors, with the purpose to make them suitable for heterogeneous kinetics studies in oxy-fuel conditions

Unsteady Simulation of CO/H2/N2/air Turbulent Non-Premixed Flame

The Sandia/ETH-Zurich CO/H2/N2 non-premixed unconfined turbulent jet flame (named ‘Flame A’) is numerically simulated by solving the unsteady compressible reactive Navier– Stokes equations in a three-dimensional axisymmetric formulation, hence, in a formally twodimensional domain. The turbulent combustion closure model adopted is the Fractal Model, FM, developed as a subgrid scale model for Large Eddy Simulation. The fuel is injected from a straight circular tube and the corresponding Reynolds number is 16 700, while the air coflows. Since the thickness of the nozzle is 0.88 mm, and the injection velocity high, ?104ms?1, capturing the stabilization mechanism of the actual flame requires high spatial resolution close to the injector. Results are first obtained on a coarse grid assuming a fast-chemistry approach for hydrogen oxidation and a single step mechanism for carbon monoxide oxidation.With this approach the flame is inevitably anchored. Then, to understand the actual flame stabilization a more complex chemical mechanism, including main radical species, is adopted. Since using this chemistry and the coarse grid of previous simulation the flame blows off numerically, attention is focused on understanding the actual flame stabilization mechanism by simulating a small spatial region close to the injection with a very fine grid. Then, analysing these results, an artificial anchoring mechanism is developed to be used in simulations of the whole flame with a coarse grid. Unsteady characteristics are shown and some averaged radial profiles for temperature and species are compared with experimental data

Unsteady analysis of hydrogen/air mild combustion by means of Large Eddy simulation

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Combustion processes are essential for power generation, since an overwhelming majority of energy-producing devices rely on the combustion of fossil or renewable fuels. Thus the development of a combustion technology able to accomplish improvement of efficiency with reduction of pollutant emissions, such as NOx, is a main concern. MILD combustion is one of the promising techniques proposed to achieve these goals. In this combustion regime the reactants are preheated above the self-ignition temperature and enough inert combustion products are entrained in the reaction region. As a result, the characteristic times of chemical kinetics and turbulent mixing are comparable and the combustion region is no longer identifiable in a flame front but extended over a wide region, so that MILD combustion is often denoted as flameless combustion. Importantly, pollutants emissions can easily reduce because of the small temperature difference between burnt and unburnt and of the lean conditions in the combustion chamber. In this work Large Eddy Simulation (LES) of a Hydrogen/Air burner operating in the MILD combustion regime is performed. Turbulent mixing controls most of the global flame properties, so computing large scale structures by means of LES is an important key to capture mixing properties. The filtered mass, momentum, energy and species equations are discretized with a 2nd order accurate central finite difference scheme over a cylindrical non-uniform grid. Unclosed terms due to subgrid-scales are modeled using a fractal model approach (FM). Radiant transfer of energy is taken into account. The predictions of temperature and pollutant formation are compared with available experimental results.vk201

Zeb2 regulates myogenic differentiation in pluripotent stem cells

Skeletal muscle differentiation is triggered by a unique family of myogenic basic helix-loop-helix transcription factors, including MyoD, MRF-4, Myf-5, and Myogenin. These transcription factors bind promoters and distant regulatory regions, including E-box elements, of genes whose expression is restricted to muscle cells. Other E-box binding zinc finger proteins target the same DNA response elements, however, their function in muscle development and regeneration is still unknown. Here, we show that the transcription factor zinc finger E-box-binding homeobox 2 (Zeb2, Sip-1, Zfhx1b) is present in skeletal muscle tissues. We investigate the role of Zeb2 in skeletal muscle differentiation using genetic tools and transgenic mouse embryonic stem cells, together with single-cell RNA-sequencing and in vivo muscle engraftment capability. We show that Zeb2 over-expression has a positive impact on skeletal muscle differentiation in pluripotent stem cells and adult myogenic progenitors. We therefore propose that Zeb2 is a novel myogenic regulator and a possible target for improving skeletal muscle regeneration. The non-neural roles of Zeb2 are poorly understood

Ancestry of the Brazilian TP53 c.1010G>A (p.Arg337His, R337H) founder mutation : clues from haplotyping of short tandem repeats on Chromosome 17p

Rare germline mutations in TP53 (17p13.1) cause a highly penetrant predisposition to a specific spectrum of early cancers, defining the Li-Fraumeni Syndrome (LFS). A germline mutation at codon 337 (p.Arg337His, c1010G>A) is found in about 0.3% of the population of Southern Brazil. This mutation is associated with partially penetrant LFS traits and is found in the germline of patients with early cancers of the LFS spectrum unselected for familial his- tory. To characterize the extended haplotypes carrying the mutation, we have genotyped 9 short tandem repeats on chromosome 17p in 12 trios of Brazilian p.Arg337His carriers. Results confirm that all share a common ancestor haplotype of Caucasian/Portuguese-Ibe- ric origin, distant in about 72–84 generations (2000 years assuming a 25 years intergenera- tional distance) and thus pre-dating European migration to Brazil. So far, the founder p. Arg337His haplotype has not been detected outside Brazil, with the exception of two resi- dents of Portugal, one of them of Brazilian origin. On the other hand, increased meiotic recombination in p.Arg337His carriers may account for higher than expected haplotype diversity. Further studies comparing haplotypes in populations of Brazil and of other areas of Portuguese migration are needed to understand the historical context of this mutation in Brazil.This study was funded by grant # 478430/2012-4 from CNPq (RFA MCT/CNPq - No 14/2012; Universal), Brazil.We would like to thank UFRGS, UFPA, AC Camargo, HC Barretos and University of Minho for their support during this work

Generation of human motor units with functional neuromuscular junctions in microfluidic devices

Neuromuscular junctions (NMJs) are specialized synapses between the axon of the lower motor neuron and the muscle facilitating the engagement of muscle contraction. In motor neuron disorders, such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), NMJs degenerate, resulting in muscle atrophy and progressive paralysis. The underlying mechanism of NMJ degeneration is unknown, largely due to the lack of translatable research models. This study aimed to create a versatile and reproducible in vitro model of a human motor unit with functional NMJs. Therefore, human induced pluripotent stem cell (hiPSC)-derived motor neurons and human primary mesoangioblast (MAB)-derived myotubes were co-cultured in commercially available microfluidic devices. The use of fluidically isolated micro-compartments allows for the maintenance of cell-specific microenvironments while permitting cell-to-cell contact through microgrooves. By applying a chemotactic and volumetric gradient, the growth of motor neuron-neurites through the microgrooves promoting myotube interaction and the formation of NMJs were stimulated. These NMJs were identified immunocytochemically through co-localization of motor neuron presynaptic marker synaptophysin (SYP) and postsynaptic acetylcholine receptor (AChR) marker α-bungarotoxin (Btx) on myotubes and characterized morphologically using scanning electron microscopy (SEM). The functionality of the NMJs was confirmed by measuring calcium responses in myotubes upon depolarization of the motor neurons. The motor unit generated using standard microfluidic devices and stem cell technology can aid future research focusing on NMJs in health and disease

RegBR : a novel Brazilian government framework to classify and analyze industryspecific regulations

Government transparency and openness are key factors to bring forth the modernization of the state. The combination of transparency and digital information has given rise to the concept of Open Government, that increases citizen understanding and monitoring of government actions, which in turn improves the quality of public services and of the government decision making process. With the goal of improving legislative transparency and the understanding of the Brazilian regulatory process and its characteristics, this paper introduces RegBR, the first national framework to centralize, classify and analyze regulations from the Brazilian government. A centralized database of Brazilian federal legislation built from automated ETL routines and processed with data mining and machine learning techniques was created. Our framework evaluates different NLP models in a text classification task on our novel Portuguese legal corpus and performs regulatory analysis based on metrics that concern linguistic complexity, restrictiveness, law interest, and industry-specific citation relevance. Our results were examined over time and validated by correlating them with known episodes of regulatory changes in Brazilian history, such as the implementation of new economic plans or the emergence of an energy crisis. Methods and metrics proposed by this framework can be used by policy makers to measure their own work and serve as inputs for future studies that could analyze government changes and their relationship with federal regulations

Dynamics of liquid He-4 in confined geometries from Time-Dependent Density Functional calculations

We present numerical results obtained from Time-Dependent Density Functional calculations of the dynamics of liquid He-4 in different environments characterized by geometrical confinement. The time-dependent density profile and velocity field of He-4 are obtained by means of direct numerical integration of the non-linear Schrodinger equation associated with a phenomenological energy functional which describes accurately both the static and dynamic properties of bulk liquid He-4. Our implementation allows for a general solution in 3-D (i.e. no symmetries are assumed in order to simplify the calculations). We apply our method to study the real-time dynamics of pure and alkali-doped clusters, of a monolayer film on a weakly attractive surface and a nano-droplet spreading on a solid surface.Comment: q 1 tex file + 9 Ps figure

MicroRNAs promote skeletal muscle differentiation of mesodermal iPSC-derived progenitors

Muscular dystrophies (MDs) are often characterized by impairment of both skeletal and cardiac muscle. Regenerative strategies for both compartments therefore constitute a therapeutic avenue. Mesodermal iPSC-derived progenitors (MiPs) can regenerate both striated muscle types simultaneously in mice. Importantly, MiP myogenic propensity is influenced by somatic lineage retention. However, it is still unknown whether human MiPs have in vivo potential. Furthermore, methods to enhance the intrinsic myogenic properties of MiPs are likely needed, given the scope and need to correct large amounts of muscle in the MDs. Here, we document that human MiPs can successfully engraft into the skeletal muscle and hearts of dystrophic mice. Utilizing non-invasive live imaging and selectively induced apoptosis, we report evidence of striated muscle regeneration in vivo in mice by human MiPs. Finally, combining RNA-seq and miRNA-seq data, we define miRNA cocktails that promote the myogenic potential of human MiPs

MTOR and STAT3 pathway hyper-activation is associated with elevated interleukin-6 levels in patients with shwachman-diamond syndrome: Further evidence of lymphoid lineage impairment

Shwachman–Diamond syndrome (SDS) is a rare inherited bone marrow failure syndrome, resulting in neutropenia and a risk of myeloid neoplasia. A mutation in a ribosome maturation factor accounts for almost all of the cases. Lymphoid involvement in SDS has not been well characterized. We recently reported that lymphocyte subpopulations are reduced in SDS patients. We have also shown that the mTOR-STAT3 pathway is hyper-activated in SDS myeloid cell populations. Here we show that mTOR-STAT3 signaling is markedly upregulated in the lymphoid compartment of SDS patients. Furthermore, our data reveal elevated IL-6 levels in cellular supernatants obtained from lymphoblasts, bone marrow mononuclear and mesenchymal stromal cells, and plasma samples obtained from a cohort of 10 patients. Of note, everolimus-mediated inhibition of mTOR signaling is associated with basal state of phosphorylated STAT3. Finally, inhibition of mTOR-STAT3 pathway activation leads to normalization of IL-6 expression in SDS cells. Altogether, our data strengthen the hypothesis that SDS affects both lymphoid and myeloid blood compartment and suggest everolimus as a potential therapeutic agent to reduce excessive mTOR-STAT3 activation in SDS