Simulation of microalgal growth in a continuous photobioreactor with sedimentation and partial biomass recycling

Microalgae are considered as promising feedstocks for the third generation of biofuels. They are autotrophic organisms with high growth rate and can stock an enormous quantity of lipids (about 20 \u2013 40% of their dried cellular weight). This work was aimed at studying the cultivation of Scenedesmus obliquus in a two-stage system composed of a photobioreactor and a settler to concentrate and partially recycle the biomass as a way to enhance the microalgae cellular productivity. It was attempted to specify by simulation and experimental data a relationship between the recycling rate, kinetic parameters of microalgal growth and photobioreactor operating conditions. Scenedesmus obliquus cells were cultivated in a lab-scale flat-plate reactor, homogenized by aeration, and running in continuous flow with a residence time of 1.66 day. Experimental data for the microalgal growth were used in a semi-empirical simulation model. The best results were obtained for Fw = 0.2FI , when R = 1 and kd = 0 and 0.05 day-1, with the biomass production in the reactor varying between 8 g L -1 and 14 g L-1, respectively. The mathematical model fitted to the microalgal growth experimental data was appropriate for predicting the efficiency of the reactor in producing Scenedesmus obliquus cells, establishing a relation between cellular productivity and the minimum recycling rate that must be used in the system

Immunopathological studies on Renibacterium salmoninarum the causative agent of bacterial kidney disease ( BKD )

Renibacterium salmoninarum isolates collected from the United States, Chile, Japan and Scotland were characterised using API ZYM, multilocus enzyme electrophoresis (MLEE), polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs). The API ZYM profiles of bacteria cultured in kidney disease medium 2 (KDM-2) without foetal calf serum (FCS) were identical in all isolates tested with only slight differences in the intensity of the reaction. However, bacteria cultured in KDM-charcoal showed a notable reduction in the production of butyrate esterase, caprylate esterase and a-glucosidase, while bacteria grown in Muller Hinton Cysteine (MH-C) failed to produce acid phosphatase. The MLEE analysis showed positive reactions for four out of the seven enzymes tested (glucose 6-phosphate, 6-phosphogluconic acid, mannose phosphate isomerase and aldose). Each of these enzymes showed the same electrophoretic type in all the isolates tested. Polyclonal antibodies anti-cell wall and anti-57 kDa protein (p57) plus seven monoclonal antibodies were produced. Three MAbs recognised peptidoglycan epitopes (14C2, 9F5, and 12B7) and three recognised p57 (5A11, 1C7/1E1 and 1C7/3D1). MAb 11D11 recognised both p57 and peptidoglycan. All MAbs were able to recognise the collection of R. salmoninarum isolates using ELISA, immunohistochemistry or Western blot. The crossreactivity of the PAbs and MAbs to 31 different bacterial pathogens was determined. No crossreaction was observed using MAbs C7/3D1 and 1C7/1E1. MAb 11D11 and 12B7 showed crossreaction only with Micrococcus luteus at very low level. PAbs showed crossreaction with several Gram positive species, particularly M. luteus and Arthrobacter sp. The ELISA analysis of the 18 renibacterial isolates using a library of PAbs and MAbs showed no significant differences between isolates except isolate B88151 which showed a significant reduction in p57. In addition, the production of renibacterial antigens was, however, shown to be dependent on the age, isolate and culture media used. The humoral immune response of rainbow trout to R. salmoninarum was investigated by injecting fish with a variety of purified antigens. The cell wall induced a strong immune response, especially when it was administered with Freund’s complete adjuvant adjuvant (FCA). Immunisation of trout with iron restricted extracellular products (ECP), normal ECP, live or heat killed bacterial cells also induced specific antibodies. Passive immunisation using some of these antibodies, followed by experimental challenge of fish, showed no evidence of protection, however there was a delay in the onset of mortality in some of the groups. By the time that 100 % mortality was reached in most of the experimental groups (day 34), only 57% mortality was observed in the group injected with MAb 1C7/1E1 and 60 % by the one injected with PAb anti cell wall. The antibody probes were also utilised to screen a R. salmoninarum gene bank and identity a gene coding for an unknown cell wall antigen The gene encoding for the major soluble antigen of R. salmoninarum (p57) was isolated and amplified from genomic renibacterial DNA using polymerase chain reaction (PCR). The gene was then inserted into the expression vector pBTtrp2 and the p57 protein synthethised by activating the tryptophan promoter

Effect of Fragarin on the Cytoplasmic Membrane of the Phytopathogen Clavibacter michiganensis

Fragarin, an antibiotic that was isolated and purified from a soluble fraction of strawberry leaves, may be a new type of preformed antimicrobial compound (phytoanticipin). Here, we report that the growth and oxygen consumption of the phytopathogenic bacterium Clavibacter michiganensis were rapidly inhibited after the addition of fragarin to cultures. Also, dissipation of the membrane potential and an increase of cell membrane permeability were observed in the presence of fragarin. The ability of fragarin to dissipate the membrane potential was confirmed with the use of small unilamellar liposomes made with lipids extracted from C. michiganensis. Our results suggest that fragarin is able to act at the membrane level, and that this action is correlated with a decrease in cell viability.Fil: Filippone, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Diaz Ricci, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Castagnaro, Atilio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Farias, Ricardo Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

História da educação matemática brasileira: entre genealogias e coletivos de pensamento

Disponível em: http://histemat.com.br/index.php/HISTEMAT/article/view/9A partir dos resultados de uma pesquisa anterior, focada na produção em História da Educação Matemática na pós-graduação stritu sensu do Brasil, entre 1990 e 2010, percebemos um crescimento das abordagens sobre vida e obra de matemáticos e professores de Matemática, história das instituições, história das disciplinas escolares, dentre outras atividades sociais e culturais. A diversidade de métodos de pesquisa historiográfica, advindas de áreas como a História, a Antropologia e a Sociologia, contribui para a construção de uma história social da Educação Matemática no contexto da sociedade e da cultura. Na continuação de nossa pesquisa buscamos apoio na epistemologia de Ludwik Fleck, associada aos estudos sobre genealogia para compreender a origem, a evolução e a disseminação das organizações sociais dos grupos de pesquisa em história da Educação Matemática. Assim, fizemos um levantamento dos grupos de pesquisas sobre história da Educação Matemática do Brasil para caracterizar suas dimensões, desmembramentos e ramificações, bem como as redes de conexões entre pesquisadores, estudantes de mestrados e doutorados, suas respectivas linhas de pesquisas e produções geradas durante a pós-graduação e após a sua inclusão no sistema de pesquisa em história da Educação Matemática no Brasil

Bioethanol from Microalgal Biomass: A Promising Approach in Biorefinery

Abstract The development of new technologies which increase the production of biofuel without directly compete with food production is required. Microalgal biomass has recently been in the highlight. The role of this biomass is here discussed within the concept of biorefinery and industrial sustainability of bioethanol production. The process of cultivation in order to accumulate around 50% of carbohydrates in the biomass (dry weight) and the importance of water and nutrient recycling are reviewed. Saccharification of biomass using enzymes or acids and alternative processes such as hydrothermal liquefaction and flash hydrolysis are addressed. Since the main monosaccharide in microalgal biomass is glucose, high rates of hydrolysis and fermentation were, generally, achieved (more than 80% of the efficiency as a sum of these two processes). Anaerobic digestion to treat vinasse and the recycling of CO2 from the ethanolic fermentation and biogas could increase the process sustainability. Alternative techniques for the concentration of bioethanol from fermentation broth and for the optimization of fuel transportation are mentioned. Finally, the advantage of using microalgae rather than other sources is estimated with reference to the production rate, even though the cultivation costs are still high

Artificial Intelligence Regulation: A Meta-Framework for Formulation and Governance

This article presents a meta-framework for Artificial Intelligence (AI) regulation that encompasses all stages of international public policy-making, from formulation to sustainable governance. Based on a vast systematic review of the literature on Artificial Intelligence Regulation (AIR) published between 2009 and 2019, a dispersed body of knowledge organized under the label “framework” was identified, containing 15 unique frameworks and several different theories that created a complex scientific scenario for research and practice. Theories and principles as diverse as Agile and Ethics were found. Thus, a structured analytical method was followed to integrate this bulk of knowledge into a cohesive, synthetic, and generic theoretical tool. The resulting “AIR framework” provides a trustworthy lens for societies to think collectively and make informed policy decisions related to what, when, and how the uses and applications of AI should be regulated. Moreover, the novel framework organizes the latest developments in the area in a format that allows future research to be framed in and added to the published literature. The (potential) impacts of AI on society are immense, and therefore the discourses, social negotiations, and applications of this technology should be guided by common grounds in terms of terminology, governance, and social values

Evaluacion clinica de la estimulacion nerviosa electrica transcutanea (Tens) como coadyuvante en el tratamiento con ferula oclusal de pacientes con dolor muscular local en los musculos masticatorios.

53 p.Se ha estudiado el efecto de la TENS como coadyuvante al tratamiento con férula oclusal de 7 pacientes con dolor en los músculos masticatorios. Los pacientes valoraron el umbral subjetivo del dolor mediante una escala visual análoga (EVA). Tras dos semanas de adaptación al uso de férula oclusal, se les sometió a tres sesiones semanales de TENS por 4 semanas. La TENS se aplico por 20 minutos, con una frecuencia de 80 Hz, una amplitud de onda de 2 Hz y la intensidad de corriente según la tolerada por el paciente. Los resultados se compararon con un grupo de 7 personas que utilizaron como tratamiento único, una férula oclusal de tipo orgánico. Todos presentaban similitud de edad, sexo y síntomas de dolor en los músculos masticatorios. Los niveles de analgesia para la terapia combinada alcanzaron el 91 % como promedio y para el tratamiento único solo el 74% como promedio. Se concluye que la terapia combinada resulta ser clínicamente mas eficaz que el tratamiento único, sin embargo, ésta eficacia no resultó ser significativa

Raleio químico em pessegueiros 'BRS Kampai'

The objective of this work was to evaluate the effect of thinning with metamitron on the fruit yield and quality of 'BRS Kampai' peach (Prunus persica) trees. The experiment was carried out in the municipality of Eldorado do Sul, in the state of Rio Grande do Sul, Brazil, in the 2016 and 2017 crop years. Treatments consisted of the application of 100, 200, 300, and 400 mg L-1 metamitron and of hand thinning 40 days after full bloom, besides control plants. Fruit abscission, effective fructification, number of fruits, and fruit yield per plant were evaluated. Regarding fruit quality, fresh fruit biomass, epidermis color, pulp firmness, soluble solids, total phenolic compounds, and antioxidant activity were assessed; fruits were also classified into diameter classes. For fruit abscission, the effect of the application of 100 mg L-1 metamitron is similar to that of hand thinning. Fruit yield and mean mass in all treatments with metamitron are similar to those obtained by hand thinning. The application of metamitron does not affect the fruit quality of peach trees. Chemical thinning with metamitron may be an alternative to hand thinning in peach trees used for the production of fruits for fresh consumption.O objetivo deste trabalho foi avaliar o efeito do raleio com metamitron sobre a produção e a qualidade dos frutos de pessegueiros 'BRS Kampai' (Prunus persica). O experimento foi realizado no Município de Eldorado do Sul, no Estado do Rio Grande do Sul, durante as safras de 2016 e 2017. Os tratamentos consistiram na aplicação de 100, 200, 300 e 400 mg L-1 de metamitron e no raleio manual aos 40 dias após a plena floração, além de plantas-testemunhas. Foram avaliados abscisão de frutos, frutificação efetiva, número de frutos e produção de frutos por planta. Em relação à qualidade dos frutos, avaliaram-se biomassa fresca, coloração da epiderme, firmeza de polpa, sólidos solúveis, compostos fenólicos totais e atividade antioxidante; os frutos também foram classificados em classes de calibre. Quanto à abscisão de frutos, o efeito da aplicação de 100 mg L-1 de metamitron é similar ao do raleio manual. A produção e a massa média dos frutos em todos os tratamentos com metamitron são similares às obtidas com o raleio manual. A aplicação de metamitron não influencia a qualidade dos frutos de pessegueiros. O raleio químico com metamitron pode ser uma alternativa ao raleio manual em pessegueiros usados para produção de frutos para consumo fresco

Preemptive effects of epidural s (+) - ketamine or ketamine in the horse's postincisional pain

O objetivo deste estudo foi avaliar o efeito analgésico da administração prévia de cetamina S(+) ou cetamina, na dor pós-inciosal em eqüinos. Utilizaram-se, em um estudo duplo-cego ao acaso, 16 éguas com idade de 6±2 anos, pesando 273,2 ± 42,0 kg. 24 horas antes do início do experimento introduziu-se um cateter epidural. No dia seguinte, as regiões isquiáticas direita e esquerda foram tricotomizadas e, a sensibilidade cutânea aferida utilizando-se os filamentos de Von Frey, tempo -30 (T-30). Realizou-se bloqueio anestésico em linha, no lado direito e, 25 minutos após administrou-se através do cateter epidural cetamina S(+) no G1 e cetamina no G2. Cinco minutos após a injeção de cetamina, realizou-se uma incisão de pele de 10 cm no lado direito, seguida de sutura. Avaliou-se a dor pós-incisional, utilizando-se os filamentos de Von Frey, a 1, 3 e 5 cm ao redor da incisão (lado incindido) e a sensibilidade cutânea (lado controle), em intervalos de 15 minutos, por 2 horas e então, 4, 6 e 8 horas após a sutura de pele. Não foram observadas alterações nas freqüências cardíaca ou respiratória e temperatura retal entre os grupos ou entre os tempos de cada grupo. Observou-se ataxia de membros pélvicos em 62,5% e 12,5% dos animais, para o G1 e G2, respectivamente. A cetamina S(+) e cetamina reduziram a sensibilidade cutânea no lado direito e esquerdo, para os estímulos mecânicos produzidos pelos filamentos de Von Frey, durante todo os período experimental. A cetamina S(+) e cetamina produziram duração de efeito analgésico similares e não interferiram nos parâmetros cardiorrespiratórios. Observou-se ataxia mais intensa e potência anestésica superior nos primeiros 60 minutos após a administração de cetamina S(+).The aim of this study was to evaluate the pre-emptive effect of epidural ketamine S (+) (SK) or racemic ketamine (RK) administration, in post-incisional pain in horses. Were used in a blinded, randomized experimental study, sixteen mixed breed mares, 6±2 years old, weighting 273.2±42.0 kg. An epidural catheter was inserted 24 hours before the trials. The thigh region was shaved bilaterally, and mechanical cutaneous sensibility was measured using von Frey filaments (T-30). Using the left side as the control one, local anesthesia was performed at the right side. Twenty-five minutes later, SK was injected in G1 or RK in G2 through the epidural catheter. Five minutes after the ketamine injection, a 10 cm skin incision was made on the right side, and then sutured. Mechanical post-incisional pain was measured using von Frey filaments, at 1, 3 and 5 cm around the incision at 15 minutes intervals, for 2 hours, then 4, 6 and 8 hours after suturing. No changes were observed in the heart and respiratory rate and rectal temperature among groups or times of each group. Hind limb ataxia was observed in 62.5% and 12.5% of G1 and G2 respectively. SK and RK reduced cutaneous sensibility in the right and the left sides to mechanical postincisional pain during all time of experiment. Epidural SK and RK produce similar post-incisional analgesic effects, did not interfere in the cardio-respiratory parameters. The SK induces more intense ataxia in mares and presents a larger analgesic potency in the first 60 minutes after the administration