Conversão Termoquímica em Leito Fixo: Características, Modelagem e Implementação do Solver biomassgasificationFoam

Os processos de conversão termoquímica são meios para converter os sólidos em portadores de energia mais convenientes (carvão), ou transformá-los em combustíveis líquidos e gasosos, ou ainda em calor ou outros produtos diversos. Muitos estudos vêm sendo realizados com o objetivo de tornar os processos termoquímicos mais eficientes e economicamente viáveis. A aplicação dos modelos de Dinâmica dos Fluidos Computacional (CFD) ajuda a otimizar o projeto e a operação dos reatores termoquímicos, como os de leito fixo. Os softwares de CFD gratuitos oferecem uma ferramenta econômica para a realização desses estudos. Um desses softwares que vem ganhando destaque é o OpenFOAM. Foi publicado recentemente um solver para o OpenFOAM chamado biomassGasificationFoam, para a simulação da gaseificação de biomassa em leito fixo. Neste trabalho foi feita uma avaliação do solver biomassGasificationFoam e das bibliotecas auxiliares que o acompanham, para generalizar a sua aplicabilidade em diversos processos de conversão termoquímica de sólidos em leito fixo. Seus modelos de transporte de calor e massa em um meio poroso reativo foram verificados e validados com testes propostos, equações analíticas e experimentos. Detalhes do código foram alterados e melhorias foram implementadas. Identificou-se uma superestimação do processo de difusão das espécies gasosas, causada por uma hipótese adotada na equação de conservação dessas espécies. O modelo cinético se mostrou adequado para processos de decomposição térmica do sólido onde a ordem da reação é unitária. Porém, esse modelo não se mostrou tão adequado para reações homogêneas do sólido onde a ordem da reação é diferente de um e para reações heterogêneas. No conjunto, o biomassGasificationFoam apresenta um potencial interessante, uma ferramenta útil para a simulação de diversos processos de conversão termoquímica de sólidos em leito fixo. Por fim, foram fornecidas informações sobre o software OpenFOAM e, principalmente, sobre o biomassGasificationFoam, com o intuito de servir como documentação para auxiliar futuros usuários interessados no seu uso

Unravelling cellular mechanisms of stem cell senescence: An aid from natural bioactive molecules

Cellular senescence plays a role in the onset of age-related pathologies and in the loss of tissue homeostasis. Natural compounds of food or plants exert an important antioxidant activity, counteracting the formation of harmful free radicals. In the presence of an intense stressing event, cells activate specific responses to counteract senescence or cell death. In the present paper, we aimed at evaluating the levels of expression of specific markers of senescence, in order to demonstrate that extracts from Myrtus Communis L. can prevent premature senescence in ADSCs exposed to oxidative stress. Cells were cultured in the presence of Myrtus extracts for 12–24 and 48 h and then incubated with H2O2 to induce senescence. We then evaluated the expression of senescence-related markers p16, p19, p21, p53, TERT, c-Myc, and the senescence-associated β-Galactoidase activity. Our results showed that pre-treatment with Myrtus extracts protects cells from premature senescence, by regulating the cell cycle, and inducing the expression of TERT and c-Myc. These findings suggest a potential application of these natural compounds in the prevention and treatment of various diseases, counteracting premature senescence and preserving tissue functions

Stem cells and physical energies: can we really drive stem cell fate?

Adult stem cells are undifferentiated elements able to self-renew or differentiate to maintain tissue integrity. Within this context, stem cells are able to divide in a symmetric fashion, feature characterising all the somatic cells, or in an asymmetric way, which leads daughter cells to different fates. It is worth highlighting that cell polarity have a critical role in regulating stem cell asymmetric division and the proper control of cell division depends on different proteins involved in cell development, differentiation and maintenance of tissue homeostasis. Moreover, the interaction between cells and the extracellular matrix are crucial in influencing cell behavior, included in terms of mechanical properties as cytoskeleton plasticity and remodelling, and membrane tension. Finally, the activation of specific transcriptional program and epigenetic modifications contributes to cell fate determination, through modulation of cellular signalling cascades. It is well known that physical and mechanical stimuli are able to influence biological systems, and in this context, the effects of electromagnetic fields (EMFs) have already shown a considerable role, even though there is a lack of knowledge and much remains to be done around this topic. In this review, we summarize the historical background of EMFs applications and the main molecular mechanism involved in cellular remodelling, with particular attention to cytoskeleton elasticity and cell polarity, required for driving stem cell behavior

Fibroblast proliferation and migration in wound healing by phytochemicals: Evidence for a novel synergic outcome

Wound-healing is a dynamic skin reparative process that results in a sequence of events, including inflammation, proliferation, and migration of different cell types as fibroblasts. Fibroblasts play a crucial role in repairing processes, from the late inflammatory phase until the fully final epithelization of the injured tissue. Within this context, identifying tools able to implement cell proliferation and migration could improve tissue regeneration. Recently, plants species from all over the world are coming out as novel tools for therapeutic applications thanks to their phytochemicals, which have antioxidant properties and can promote wound healing. In this paper, we aimed at investigating antioxidant activity of waste extracts from different medicinal plants, endemic of the Mediterranean area, on fibroblast proliferation and wound healing. We determined the amount of total phenols and anti-oxidant activity by ABTS assay. We then evaluated the cytotoxicity of the compounds and the proliferative capabilities of fibroblasts by scratch assay. Our results showed that waste extracts retain antioxidant and regenerative properties, inducing tissue re-establishment after environmental stress exposure. Taken together, our findings suggest that waste material could be used in the future also in combinations to stimulate wound healing processes and antioxidant responses in damaged skin

Conflitos ambientais a luz dos pressupostos procedimentais de democracia

Os conflitos ambientais, em especial na Região Sul-Fluminense, representam uma parcela significativa das questões de tensão entre sociedade, empresariado e Poder Público, gerando atritos na relação entre estes atores. A aplicação de técnicas de mediação, por meio do seu potencial racionalizador do debate, torna-se um instrumento teórico importante para a resolução dos conflitos ambientais. Isto porque, enquanto os ecossistemas sofrem alterações lentas e continuas devido às leis físicas, a história demonstra uma aceleração progressiva da evolução pela qual passa o homem, que, para satisfazer suas necessidades ilimitadas, disputa os bens da natureza, que são limitados, acentuando o desequilíbrio ecológico e, consequentemente, gerando conflitos na comunidade, pois se utilizam recursos pertencentes às gerações futuras. A criação de medidas alternativas como o desenvolvimento sustentável, cuja característica principal consiste na possível e desejável conciliação entre o desenvolvimento, a preservação do meio ambiente e a melhoria da qualidade de vida, seria uma forma de resolução do problema. O desenvolvimento sustentável é um processo de mudança no qual o uso de recursos, as políticas econômicas, a dinâmica populacional e as estruturas institucionais estão em harmonia e reforçam o potencial atual e futuro para o progresso humano. Apesar de reconhecer que as atividades econômicas devem caber à iniciativa privada, a busca do desenvolvimento sustentável exigirá, sempre que necessário, a interação dos atores envolvidos nos campos social, ambiental, econômico, judicial e de ordem pública, de modo a garantir democraticamente um mínimo de qualidade devida para todos. E tal objetivo será concretizado a partir da utilização da mediação como instrumento de resolução dos conflitos mencionados.

SMARCB1/INI1 loss in skull base conventional chordomas: a clinicopathological and molecular analysis

Introduction: The loss of SMARCB1/INI1 protein has been recently described in poorly differentiated chordoma, an aggressive and rare disease variant typically arising from the skull base. Methods: Retrospective study aimed at 1) examining the differential immunohistochemical expression of SMARCB1/INI1 in conventional skull base chordomas, including the chondroid subtype; 2) evaluating SMARCB1 gene deletions/copy number gain; and 3) analyzing the association of SMARCB1/INI1 expression with clinicopathological parameters and patient survival. Results: 65 patients (35 men and 30 women) affected by conventional skull base chordoma, 15 with chondroid subtype, followed for >48 months after surgery were collected. Median age at surgery was 50 years old (range 9-79). Mean tumor size was 3.6 cm (range 2-9.5). At immunohistochemical evaluation, a partial loss of SMARCB1/INI1 (>10% of neoplastic examined cells) was observed in 21 (32.3%) cases; the remaining 43 showed a strong nuclear expression. Fluorescence in situ hybridization (FISH) analysis was performed in 15/21 (71.4%) cases of the chordomas with partial SMARCB1/INI1 loss of expression. Heterozygous deletion of SMARCB1 was identified in 9/15 (60%) cases and was associated to copy number gain in one case; no deletion was found in the other 6 (40%) cases, 3 of which presenting with a copy number gain. No correlations were found between partial loss of SMARCB1/INI1 and the clinicopathological parameters evaluated (i.e., age, tumor size, gender, tumor size and histotype). Overall 5-year survival and 5-year disease-free rates were 82% and 59%, respectively. According to log-rank test analysis the various clinico-pathological parameters and SMARCB1/INI1 expression did not impact on overall and disease free-survival. Discussion: Partial loss of SMARCB1/INI1, secondary to heterozygous deletion and/or copy number gain of SMARCB1, is not peculiar of aggressive forms, but can be identified by immunohistochemistry in a significant portion of conventional skull base chordomas, including the chondroid subtype. The variable protein expression does not appear to correlate with clinicopathological parameters, nor survival outcomes, but still, it could have therapeutic implications

Epigenetics, stem cells, and autophagy: Exploring a path involving miRNA

MiRNAs, a small family of non-coding RNA, are now emerging as regulators of stem cell pluripotency, differentiation, and autophagy, thus controlling stem cell behavior. Stem cells are undifferentiated elements capable to acquire specific phenotype under different kind of stimuli, being a main tool for regenerative medicine. Within this context, we have previously shown that stem cells isolated from Wharton jelly multipotent stem cells (WJ-MSCs) exhibit gender differences in the expression of the stemness related gene OCT4 and the epigenetic modulator gene DNA-Methyltransferase (DNMT1). Here, we further analyze this gender difference, evaluating adipogenic and osteogenic differentiation potential, autophagic process, and expression of miR-145, miR-148a, and miR-185 in WJ-MSCs derived from males and females. These miRNAs were selected since they are involved in OCT4 and DNMT1 gene expression, and in stem cell differentiation. Our results indicate a difference in the regulatory circuit involving miR-148a/DNMT1/OCT4 autophagy in male WJ-MSCs as compared to female cells. Moreover, no difference was detected in the expression of the two-differentiation regulating miRNA (miR-145 and miR-185). Taken together, our results highlight a different behavior of WJ-MSCs from males and females, disclosing the chance to better understand cellular processes as autophagy and stemness, usable for future clinical applications

Antisenescence Effect of REAC Biomodulation to Counteract the Evolution of Myelodysplastic Syndrome

About 30 percent of patients diagnosed with myelodysplastic syndromes (MDS) progress to acute myeloid leukemia (AML). The senescence of bone marrow‐derived mesenchymal stem cells (BMSCs) seems to be one of the determining factors in inducing this drift. Research is continuously looking for new methodologies and technologies that can use bioelectric signals to act on senescence and cell differentiation towards the phenotype of interest. The Radio Electric Asymmetric Conveyer (REAC) technology, aimed at reorganizing the endogenous bioelectric activity, has already shown to be able to determine direct cell reprogramming effects and counteract the senescence mechanisms in stem cells. Aim of the present study was to prove if the anti-senescence results previously obtained in different kind of stem cells with the REAC Tissue optimization – regenerative (TO-RGN) treatment, could also be observed in BMSCs, evaluating cell viability, telomerase activity, p19ARF, P21, P53, and hTERT gene expression. The results show that the REAC TORGN treatment may be a useful tool to counteract the BMSCs senescence which can be the basis of AML drift. Nevertheless, further clinical studies on humans are needed to confirm this hypothesis

Indications and Limits of Surgery for Spinal Metastases Derived from Lung Cancer: A Single-Center Experience

Lung cancer is the second most frequently diagnosed cancer in the world, and surgery is an integral part of the treatment for spinal metastases. The aims of this retrospective study were to assess the overall survival of surgically treated patients affected by lung cancer spinal metastases and identify any factors related to a better survival rate. We recruited 56 consecutive patients (34 male and 22 female) surgically treated for metastatic lung cancer in the spine from 2009 to 2019. Surgical indications were based on a previously published and validated flow chart following a multidisciplinary evaluation. We assessed the localization of vertebral metastases, the presence of other bone or visceral metastases, neurological status according to the Frankel score, ambulatory autonomy, and general status, measured with the Karnofsky performance scale. The expected prognosis was retrospectively assessed according to the revised Tokuhashi score. The median survival was 8.1 months, with over a third of patients surviving more than 1 year. We observed a global improvement in all clinical parameters after surgical treatment. The Tokuhashi predictive score did not correlate with survival after surgery. The results of this study suggest that the surgical treatment of symptomatic spinal metastases from lung cancer can improve quality of life, even in patients with a shorter life expectancy, by controlling pain and improving autonomy

Minimum decoherence cat-like states in Gaussian noisy channels

We address the evolution of cat-like states in general Gaussian noisy channels, by considering superpositions of coherent and squeezed-coherent states coupled to an arbitrarily squeezed bath. The phase space dynamics is solved and decoherence is studied keeping track of the purity of the evolving state. The influence of the choice of the state and channel parameters on purity is discussed and optimal working regimes that minimize the decoherence rate are determined. In particular, we show that squeezing the bath to protect a non squeezed cat state against decoherence is equivalent to orthogonally squeezing the initial cat state while letting the bath be phase insensitive.Comment: 10 pages, 2 figures, references added, submitted to J. Opt.