Termodinamica do equilibrio aplicada a destilação etanol-agua

Orientador: Saul Gonçalves D'AvilaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de CampinasResumo: Propõe-se método para o teste da consistência termodinâmica de dados experimentais de equilíbrio líquido-vapor para sistemas binários, através da integração da equação da coexistência. Este método dispensa a utilização de correlações para o coeficiente de atividade e pressões de saturação, tendo se mostrado de boa sensibilidade. A seguir, o método da equação da coexistência é utilizado na análise da consistência dos dados etanol-água da literatura. Desta forma, selecionam-se conjuntos de dados isotérmicos aos quais são ajustadas equações para o coeficiente de atividade, com parâmetros dependentes da temperatura, o que melhora sensivelmente o ajuste. As equações UNIQUAC e de van Laar são as que apresentam melhores resultados. As correlações assim obtidas são usadas na simulação da destilação do álcool etílico através do modelo de coluna de Naphtali-Sandholm. Analisa-se, por fim, a influência de simplificações nos cálculos termodinâmicos sobre os resultados desta simulação.Abstract: A method for testing the thermodynamic consistency of experimental liquid-vapor equilibrium data for binary systems through the integration of the coexistence equation is proposed. This method exempts from the use of correlations for both the activity coefficient and saturation pressures and shows a good sensibility. The coexistence equation method is then used for checking the consistency of ethanol-water data, found in the literature. In this way, groups of isothermal data are selected and equations for the activity coefficient, with temperature dependent parameters, are adjusted to them, improving the fit. The UNIQUAC and van Laar equations show the best results. The obtained correlations are used for simulating the destillation of ethyl alcohol through the model of Naphtali Sandholm. The influence of some simplifications in the thermodynamic calculations over the simulation results is verified.MestradoMestre em Engenharia Químic

Análise de fluxos metabólicos com substrato isotopicamente marcado (13C-MFA) em S. typhimurium

Linhagens atenuadas de Salmonella têm sido estudadas para produção e veiculação de substâncias com fins terapêuticos. Modelos metabólicos à escala genômica são ferramentas importantes no desenvolvimento de estratégias de engenharia metabólica. Este trabalho teve por objetivo obter dados experimentais para aprimorar o modelo metabólico e aprofundar o conhecimento do metabolismo de S. typhimurium (St). Foram realizados cultivos contínuos à taxa de diluição (D) de 0,24 e 0,48 h-1, utilizando U-13C-glicose como substrato. Aminoácidos da biomassa foram analisados por GC-MS. A análise de fluxos metabólicos permitiu determinar a distribuição de fluxos nas principais vias metabólicas de St. A glicólise foi a via majoritamente utilizada para catabolisar a glicose. As maiores diferenças nos fluxos estimados, para as duas D, verificaram-se nas vias anapleróticas. Sobrepondo os dados de fluxos intracelulares ao modelo metabólico será gerado um modelo mais preciso do metabolismo de S. typhimurium

Metabolic profiling of secreted fermentative byproducts by Salmonella typhimurium

Salmonella typhimurium is a pathogenic bacterium that has been studied to be used as a platform for vaccine development as a live bacterial vector (LBV). It is closely related to other enterobacteria like E. coli, but presents some metabolic differences regarding the efficiency of biomass and energy production. This work presents a metabolic profile of the main byproducts excreted by S. typhimurium aiming to evaluate the distribution of carbon between respiratory and fermentative pathways for this bacterium. A genome scale metabolic model (GSMM) of S. typhimurium was also used to simulate the phenotypic behavior of this bacterium under the studied conditions and compare the experimental results to the model predictions. Simulations were performed using the free software Optflux and biomass maximization was used as the objective function for Flux Balance Analysis (FBA). Experimental cultivations were conducted in 2 L bioreactors with a working volume of 0.8 L under varying dilution rates (D) of 0.1, 0.24, 0.5, 0.58 and 0.67 h-1, using 10.0 g/L of glucose as the sole carbon source and M9 minimum medium. The dissolved oxygen concentration was kept at 30 % of its saturation, and pH and temperature were kept constant at 7.0 and 37°C, respectively. Supernatant samples were analyzed by HPLC to measure glucose consumption rate and fermentative products formation. Our initial results showed an intense production of organic acids by S. typhimurium, mainly acetic acid, at increasing amounts for higher dilution rates, and starting from the lower dilution rate studied. From D of 0.5 to D = 0.67 h-1 formate was also produced, and the secretion rates of both by-products increased linearly with the growth rate. These results may reflect some metabolic limitations of the species under investigation concerning its respiratory capacity, as the fermentative pathways seem to be active even under low growth rates and aerobic conditions, what is not observed for E. coli. It is also noteworthy that a considerable fraction of the carbon consumed is directed to the formation of these metabolites, compromising the biomass formation. Simulation results employing the free software Optflux 3.0.7 and the GSMM STM_v1.0 predicted some aspects of the fermentative behavior observed in the experiments, but with low accuracy, indicating that the model employed (that was constructed based on an E. coli model) does not reflect the differences between the metabolism of these two closed related bacteria. Results from this work will be incorporated in the model to increase its predictive capacity regarding the organic acids formation by Salmonella cells

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

EVALUATING THE ROLE OF GEOMETRICAL FEATURES OF A TAYLOR VORTEX BIOREACTOR TO CULTURE ANIMAL CELLS BY USING COMPUTATIONAL FLUID DYNAMICS

International audienceTaylor bioreactor is fast becoming the next bioreactor to culture animal cells due to milder shear and homogenous flow structures throughout the bioreactor in comparison to the traditional stirred tank. However, there is not much information in the literature about how geometrical aspects of the Taylor bioreactor may affect the culture of animal cells which could result in poor efficiency. As a result, six different geometrical conditions of Taylor bioreactor are presented, related to off-bottom clearance and the external cylinders' bottom shape, after conducting a detailed grid and time-step independence study and validating with experimental results. Simulations were conducted at Reynolds number of 12077 and Taylor number of 5331 with a radius ratio of 0.84 and aspect ratio of 19.8. Throughout the bulk zone equivalent of 80 % of the gap-width, the mean velocity was found to be around 50 % of the maximum with similar gradients which is encouraging for cultivating of animal cells in Taylor bioreactor in comparison with spinner flask and stirred tank bioreactors where the gradients are much less uniform. Curved bottom surfaces of the external cylinder and higher off-bottom clearance areas adversely affect the flow structures creating dead-zone areas in the off-bottom clearance area

Enzymatic Synthesis of Fatty Acid Isoamyl Monoesters from Soybean Oil Deodorizer Distillate: A Renewable and Ecofriendly Base Stock for Lubricant Industries

In this study, soybean oil deodorizer distillate (SODD), a mixture of free fatty acids and acylglycerides, and isoamyl alcohol were evaluated as substrates in the synthesis of fatty acid isoamyl monoesters catalyzed by Eversa (a liquid formulation of Thermomyces lanuginosus lipase). SODD and the products were characterized by the chemical and physical properties of lubricant base stocks. The optimal conditions to produce isoamyl fatty acid esters were determined by response surface methodology (RSM) using rotational central composite design (RCCD, 23 factorial + 6 axial points + 5 replications at the central point); they were 1 mol of fatty acids (based on the SODD saponifiable index) to 2.5 mol isoamyl alcohol, 45 °C, and 6 wt.% enzymes (enzyme mass/SODD mass). The effect of the water content of the reactional medium was also studied, with two conditions of molecular sieve ratio (molecular sieve mass/SODD mass) selected as 39 wt.% (almost anhydrous reaction medium) and 9 wt.%. Ester yields of around 50 wt.% and 70 wt.% were reached after 50 h reaction, respectively. The reaction products containing 43.7 wt.% and 55.2 wt.% FAIE exhibited viscosity indices of 175 and 163.8, pour points of −6 °C and −9 °C, flash points of 178 and 104 °C, and low oxidative stability, respectively. Their properties (mainly very high viscosity indices) make them suitable to be used as base stocks in lubricant formulation industries