Elastic properties of graphyne-based nanotubes

Graphyne nanotubes (GNTs) are nanostructures obtained from rolled up graphyne sheets, in the same way carbon nanotubes (CNTs) are obtained from graphene ones. Graphynes are 2D carbon-allotropes composed of atoms in sp and sp2 hybridized states. Similarly to conventional CNTs, GNTs can present different chiralities and electronic properties. Because of the acetylenic groups (triple bonds), GNTs exhibit large sidewall pores that influence their mechanical properties. In this work, we studied the mechanical response of GNTs under tensile stress using fully atomistic molecular dynamics simulations and density functional theory (DFT) calculations. Our results show that GNTs mechanical failure (fracture) occurs at larger strain values in comparison to corresponding CNTs, but paradoxically with smaller ultimate strength and Young's modulus values. This is a consequence of the combined effects of the existence of triple bonds and increased porosity/flexibility due to the presence of acetylenic groups

Resonance Raman scattering studies in Br-2-adsorbed double-wall carbon nanotubes

ArticlePhysical Review B. 73(23):235413 (2006)journal articl

Applications of the “respirometric” method as a tool for on-line control of composting processes

The environmental crisis in our contemporary, globalized world, is facing a paradigm: the company now has a major technological development, and is also a society that destroys most in history. All the achievements of our civilization provide various negative factors, such as fast-paced population growth, depletion of natural resources, expansion of consumption of materials and production systems that use polluting production processes and waste, which if not treated and/or properly designed produce imbalances in the biosphere, changing vital ecosystems. In seeking solutions to the disposal of waste organic solids, we find that the composting process can be considered one of the most appropriate alternatives in the environmental point of view, promoting greater recycling and more appropriate in terms of material and energy when compared with other methods. This search of the society for better environmental conditions, points to a tendency to experience a substantial increase in the amount of sludge to be disposed of in the coming years, it appears, therefore, need to be presented techniques that allow an efficient and adequate treatment of them. The use of the composting process in Brazil is still very limited, the high degree of empiricism used in the control and evaluation process for lack of more indepth technical knowledge, not giving rise to the implementation of new forms of analysis and effective control. In the evaluation process called the method "respirometric", uses a new methodology in which the parameters of biological degradation of waste is not measured in the solid phase, but in the gas phase. The analysis in the gas phase has the advantage of greater representativeness, precision and reliability, to be totally homogeneous. The parameters measured in the gas phase of the composting process of sewage sludge, determine the temporal evolution of O2 consumption and CO2 and their generation, these gases are analyzed, recorded, the data are sent to a computer that displays the results instantly.A crise ambiental no nosso mundo contemporâneo globalizado, enfrenta um paradigma: a sociedade que agora tem seu maior desenvolvimento tecnológico, e é também uma sociedade que mais destrói na história. Todas as conquistas da nossa civilização propiciam diferentes fatores negativos: como o crescimento demográfico em ritmo acelerado, o esgotamento dos recursos naturais, expansão do consumo de materiais e sistemas de produção que utilizam processos de produção poluentes e geradores de resíduos, que se não tratados e/ou destinados adequadamente produzirão desequilíbrios na biosfera, alterando os ecossistemas. Na procura de soluções para a destinação dos resíduos sólidos orgânicos, encontramos o processo de compostagem que pode ser considerado uma das alternativas mais adequadas sob o ponto de vista ambiental, promovendo uma maior e mais apropriada reciclagem, em termos de material e de energia, quando comparadas com outros métodos. Esta busca da sociedade por melhores condições ambientais, aponta para uma tendência de ocorrer um incremento substancial na quantidade de lodo a ser disposto nos próximos anos, surgindo, portanto, a necessidade que sejam apresentadas técnicas que possibilitem um tratamento eficiente e adequado dos mesmos. O emprego do processo de compostagem no Brasil, é ainda bastante restrito, pelo alto grau de empirismo utilizado no controle e avaliação do processo, por falta de conhecimento técnico mais aprofundado, não dando origem ao implemento de novas formas de análise e controle eficazes. No processo avaliativo chamado método "respirométrico", utiliza-se uma nova metodologia na qual os parâmetros de degradação biológica dos resíduos não são medidos na fase sólida, mas em sua fase gasosa. A análise realizada na fase gasosa tem como vantagens uma maior representatividade, precisão e confiabilidade, por ser totalmente homogênea. Os parâmetros medidos na fase gasosa do processo de compostagem do lodo de esgoto, determinam a evolução temporal de consumo de O2 e sua geração de CO2 e, estes gases são analisados, registrados, os dados obtidos são enviados para um computador que apresenta os resultados instantaneamente.Asociación de Universidades Grupo Montevide

Covid-19 Dynamic Monitoring and Real-Time Spatio-Temporal Forecasting

Background: Periodically, humanity is often faced with new and emerging viruses that can be a significant global threat. It has already been over a century post—the Spanish Flu pandemic, and we are witnessing a new type of coronavirus, the SARS-CoV-2, which is responsible for Covid-19. It emerged from the city of Wuhan (China) in December 2019, and within a few months, the virus propagated itself globally now resulting more than 50 million cases with over 1 million deaths. The high infection rates coupled with dynamic population movement demands for tools, especially within a Brazilian context, that will support health managers to develop policies for controlling and combating the new virus. / Methods: In this work, we propose a tool for real-time spatio-temporal analysis using a machine learning approach. The COVID-SGIS system brings together routinely collected health data on Covid-19 distributed across public health systems in Brazil, as well as taking to under consideration the geographic and time-dependent features of Covid-19 so as to make spatio-temporal predictions. The data are sub-divided by federative unit and municipality. In our case study, we made spatio-temporal predictions of the distribution of cases and deaths in Brazil and in each federative unit. Four regression methods were investigated: linear regression, support vector machines (polynomial kernels and RBF), multilayer perceptrons, and random forests. We use the percentage RMSE and the correlation coefficient as quality metrics. / Results: For qualitative evaluation, we made spatio-temporal predictions for the period from 25 to 27 May 2020. Considering qualitatively and quantitatively the case of the State of Pernambuco and Brazil as a whole, linear regression presented the best prediction results (thematic maps with good data distribution, correlation coefficient >0.99 and RMSE (%) <4% for Pernambuco and around 5% for Brazil) with low training time: [0.00; 0.04 ms], CI 95%. / Conclusion: Spatio-temporal analysis provided a broader assessment of those in the regions where the accumulated confirmed cases of Covid-19 were concentrated. It was possible to differentiate in the thematic maps the regions with the highest concentration of cases from the regions with low concentration and regions in the transition range. This approach is fundamental to support health managers and epidemiologists to elaborate policies and plans to control the Covid-19 pandemics

COVID-SGIS: A Smart Tool for Dynamic Monitoring and Temporal Forecasting of Covid-19

Background: The global burden of the new coronavirus SARS-CoV-2 is increasing at an unprecedented rate. The current spread of Covid-19 in Brazil is problematic causing a huge public health burden to its population and national health-care service. To evaluate strategies for alleviating such problems, it is necessary to forecast the number of cases and deaths in order to aid the stakeholders in the process of making decisions against the disease. We propose a novel system for real-time forecast of the cumulative cases of Covid-19 in Brazil. / Methods: We developed the novel COVID-SGIS application for the real-time surveillance, forecast and spatial visualization of Covid-19 for Brazil. This system captures routinely reported Covid-19 information from 27 federative units from the Brazil.io database. It utilizes all Covid-19 confirmed case data that have been notified through the National Notification System, from March to May 2020. Time series ARIMA models were integrated for the forecast of cumulative number of Covid-19 cases and deaths. These include 6-days forecasts as graphical outputs for each federative unit in Brazil, separately, with its corresponding 95% CI for statistical significance. In addition, a worst and best scenarios are presented. / Results: The following federative units (out of 27) were flagged by our ARIMA models showing statistically significant increasing temporal patterns of Covid-19 cases during the specified day-to-day period: Bahia, Maranhão, Piauí, Rio Grande do Norte, Amapá, Rondônia, where their day-to-day forecasts were within the 95% CI limits. Equally, the same findings were observed for Espírito Santo, Minas Gerais, Paraná, and Santa Catarina. The overall percentage error between the forecasted values and the actual values varied between 2.56 and 6.50%. For the days when the forecasts fell outside the forecast interval, the percentage errors in relation to the worst case scenario were below 5%. / Conclusion: The proposed method for dynamic forecasting may be used to guide social policies and plan direct interventions in a cost-effective, concise, and robust manner. This novel tools can play an important role for guiding the course of action against the Covid-19 pandemic for Brazil and country neighbors in South America

Metaplastic breast carcinomas exhibit EGFR, but not HER2, gene amplification and overexpression: immunohistochemical and chromogenic in situ hybridization analysis

INTRODUCTION: Metaplastic breast carcinomas constitute a heterogeneous group of neoplasms, accounting for less than 1% of all invasive mammary carcinomas. Approximately 70–80% of metaplastic breast carcinomas overexpress the epidermal growth factor receptor (EGFR). Human epidermal growth factor receptor (HER)2 and EGFR have attracted much attention in the medical literature over the past few years owing to the fact that humanized monoclonal antibodies against HER2 and therapies directed against the extracellular ligand-binding domain or the intracellular tyrosine kinase domain of EGFR have proven successful in treating certain types of human cancer. We investigated whether HER2 and EGFR overexpression was present and evaluated gene amplification in a series of metaplastic breast carcinomas. METHOD: Twenty-five metaplastic breast carcinomas were immunohistochemically analyzed using a monoclonal antibody (31G7) for EGFR and two antibodies for HER2 (Herceptest and CB11) and scored using the Herceptest scoring system. Gene amplification was evaluated by chromogenic in situ hybridization using Zymed Spot-Light EGFR and HER2 amplification probe. The results were evaluated by bright field microscopy under 40× and 63× objective lenses. RESULTS: Nineteen (76%) metaplastic breast carcinomas exhibited EGFR ovexpression, and among these EGFR amplification (defined either by large gene clusters or >5 signals/nucleus in >50% of neoplastic cells) was detected in seven cases (37%): three carcinomas with squamous differentiation and four spindle cell carcinomas. One case exhibited HER2 overexpression of grade 2+ (>10% of cells with weak to moderate complete membrane staining), but HER2 gene amplification was not detected. CONCLUSION: Metaplastic breast carcinomas frequently overexpressed EGFR, which was associated with EGFR gene amplification in one-third of cases. Our findings suggest that some patients with metaplastic breast carcinomas might benefit from novel therapies targeting EGFR. Because most metaplastic breast carcinomas overexpress EGFR without gene amplification, further studies to evaluate EGFR activating mutations are warranted