A blockchain-based information market to incentivise cooperation in swarms of self-interested robots.

Robot swarms are generally considered to be composed of cooperative agents that, despite their limited individual capabilities, can perform difficult tasks by working together. However, in open swarms, where different robots can be added to the swarm by different parties with potentially competing interests, cooperation is but one of many strategies. We envision an information market where robots can buy and sell information through transactions stored on a distributed blockchain, and where cooperation is encouraged by the economy itself. As a proof of concept, we study a classical foraging task, where exchanging information with other robots is paramount to accomplish the task efficiently. We illustrate that even a single robot that lies to others-a so-called Byzantine robot-can heavily disrupt the swarm. Hence, we devise two protection mechanisms. Through an individual-level protection mechanism, robots are more sceptical about others' information and can detect and discard Byzantine information, at the cost of lower efficiency. Through a systemic protection mechanism based on economic rules regulating robot interactions, robots that sell honest information acquire over time more wealth than Byzantines selling false information. Our simulations show that a well-designed robot economy penalises misinformation spreading and protects the swarm from Byzantine behaviour. We believe economics-inspired swarm robotics is a promising research direction that exploits the timely opportunity for decentralised economies offered by blockchain technology.

Robot swarms neutralize harmful Byzantine robots using a blockchain-based token economy.

Through cooperation, robot swarms can perform tasks or solve problems that a single robot from the swarm could not perform/solve by itself. However, it has been shown that a single Byzantine robot (such as a malfunctioning or malicious robot) can disrupt the coordination strategy of the entire swarm. Therefore, a versatile swarm robotics framework that addresses security issues in inter-robot communication and coordination is urgently needed. Here, we show that security issues can be addressed by setting up a token economy between the robots. To create and maintain the token economy, we used blockchain technology, originally developed for the digital currency Bitcoin. The robots were given crypto tokens that allowed them to participate in the swarm's security-critical activities. The token economy was regulated via a smart contract that decided how to distribute crypto tokens among the robots depending on their contributions. We designed the smart contract so that Byzantine robots soon ran out of crypto tokens and could therefore no longer influence the rest of the swarm. In experiments with up to 24 physical robots, we demonstrated that our smart contract approach worked: The robots could maintain blockchain networks, and a blockchain-based token economy could be used to neutralize the destructive actions of Byzantine robots in a collective-sensing scenario. In experiments with more than 100 simulated robots, we studied the scalability and long-term behavior of our approach. The obtained results demonstrate the feasibility and viability of blockchain-based swarm robotics.

Toxicological interactions induced by chronic exposure to gold nanoparticles and microplastics mixtures in Daphnia magna.

The effects of emerging environmental contaminants on human and environmental health is of high concern, especially those potentially induced by mixtures. The main goal of the present study was to assess the chronic effects of mixtures of citrate stabilized ≈5 nm gold nanoparticles (AuNP) and 1-5µm microplastics (MP) on Daphnia magna. A 21-day bioassay was carried out. The effect criteria were parental mortality, somatic growth and several reproductive parameters. AuNP induced parental mortality, reduced the total offspring and caused immobile juveniles and aborted eggs. MP induced parental mortality, delayed the first brood release, decreased the number of broods released, the total offspring, and caused immobile juveniles. All the mixtures caused higher toxicity than AuNP and MP alone. Based on parental mortality, evidences of antagonism between AuNP and MP were observed at low concentrations of both mixture components, whereas evidences of synergism at high concentrations were found. Chronic (21-day) exposure of D. magna to AuNPs, MP, and their mixtures can impair development, reproduction, ultimately leading to death.

NAVIGATED VERSUS MECHANICAL KNEE REPLACEMENT: COMPARISON BETWEEN INITIAL NAVIGATED AND CONVENTIONAL CASES PERFORMED BY THE SAME SURGEON.

OBJECTIVE: The postoperative mechanical axis in 36 cases of total knee arthroplasty using navigated and mechanical alignment systems was evaluated and compared. All the operations were performed over the same period by the same surgeon and team, who were beginners in the navigated technique and experienced in the mechanical technique. METHODS: Between 2008 and 2010, 36 total knee prostheses were performed and compared: 25 navigated and 11 mechanical procedures. Any deviation from the axis measured on the panoramic postoperative X-ray was considered positive. RESULTS: The navigated prostheses produced a mean axis deviation of 1.32 degrees and standard deviation of 1.57 degrees and the mechanical, respectively 3.18 and 2.99 degrees. There was better alignment with a tendency towards a statistical difference favoring the navigated technique. CONCLUSION: There were significantly more cases with axis deviation greater than three degrees using the mechanical technique. The navigated technique was incorporated by this team without additional complications and, even without experience of navigated surgery, the initial cases achieved better alignment than with the mechanical technique, and a significantly smaller number of outliers from the three-degree safety zone.

Artroplastia do joelho navegada x mecânica: comparação entre casos iniciais de navegação e convencionais pelo mesmo cirurgião / Navigated versus mechanical knee replacement: comparison between initial navigated and conventional cases performed by the same surgeon

OBJETIVO: Foram avaliados e comparados os eixos mecânicos pós-operatórios de 36 artroplastias totais de joelho pelos sistemas de alinhamento navegado e mecânico feitos no mesmo período pelo mesmo cirurgião e equipe, iniciantes na técnica navegada e com experiência na técnica mecânica. MÉTODOS: Entre 2008 e 2010, 36 próteses totais de joelho foram executadas e comparadas, 25 navegadas e 11 mecânicas. Qualquer desvio de eixo medido no RX panorâmico pós-operatório foi considerado positivo. RESULTADOS: As próteses navegadas obtiveram média de desvio de eixo de 1,32 graus e desvio padrão de 1,57 graus e as mecânicas, respectivamente, 3,18 e 2,99 graus. Houve um melhor alinhamento com tendência à diferença estatística em favor da técnica navegada. CONCLUSÃO: Os casos com desvio de eixo maior que três graus foram significativamente maiores na técnica mecânica. A técnica por navegação foi incorporada por nossa equipe sem complicações adicionais e, mesmo sem experiência em cirurgia navegada, os primeiros casos obtiveram melhor alinhamento em relação à técnica mecânica e número significativamente menor de casos fora da zona de segurança de três graus em relação ao eixo mecânico.

OBJETIVE: The postoperative mechanical axis in 36 cases of total knee arthroplasty using navigated and mechanical alignment systems was evaluated and compared. All the operations were performed over the same period by the same surgeon and team, who were beginners in the navigated technique and experienced in the mechanical technique. METHODS: Between 2008 and 2010, 36 total knee prostheses were performed and compared: 25 navigated and 11 mechanical procedures. Any deviation from the axis measured on the panoramic postoperative X-ray was considered positive. RESULTS: The navigated prostheses produced a mean axis deviation of 1.32 degrees and standard deviation of 1.57 degrees and the mechanical, respectively 3.18 and 2.99 degrees. There was better alignment with a tendency towards a statistical difference favoring the navigated technique. CONCLUSION: There were significantly more cases with axis deviation greater than three degrees using the mechanical technique. The navigated technique was incorporated by this team without additional complications and, even without experience of navigated surgery, the initial cases achieved better alignment than with the mechanical technique, and a significantly smaller number of outliers from the three-degree safety zone.

Ethanol production by fermentation using immobilized cells of Saccharomyces cerevisiae in cashew apple bagasse.

In this work, cashew apple bagasse (CAB) was used for Saccharomyces cerevisiae immobilization. The support was prepared through a treatment with a solution of 3% HCl, and delignification with 2% NaOH was also conducted. Optical micrographs showed that high populations of yeast cells adhered to pre-treated CAB surface. Ten consecutive fermentations of cashew apple juice for ethanol production were carried out using immobilized yeasts. High ethanol productivity was observed from the third fermentation assay until the tenth fermentation. Ethanol concentrations (about 19.82-37.83 g L(-1) in average value) and ethanol productivities (about 3.30-6.31 g L(-1) h(-1)) were high and stable, and residual sugar concentrations were low in almost all fermentations (around 3.00 g L(-1)) with conversions ranging from 44.80% to 96.50%, showing efficiency (85.30-98.52%) and operational stability of the biocatalyst for ethanol fermentation. Results showed that cashew apple bagasse is an efficient support for cell immobilization aiming at ethanol production.

Positioning of the femoral tunnel for arthroscopic reconstruction of the anterior cruciate ligament: comparative study of 2 techniques.

OBJECTIVE: To compare the accuracy of positioning of the femoral tunnel in reconstructing the anterior cruciate ligament by means of 2 techniques: tibial tunnel and anteromedial portal. METHOD: Femoral tunnels were drilled in 20 knees from human cadavers by means of arthroscopy. Group I had the femoral tunnel drilled via a trans-tibial tunnel, and Group II via the anteromedial portal. Four variables were measured: A) posterior wall thickness; B) tunnel positioning at the notch; C) tunnel inclination in relation to the femoral axis; and D) distance between the wire guide exit and the lateral epicondyle. RESULTS: As above, respectively, A) 2.23 mm for group I and 2.36 mm for group II (P =.54); B) 25.5 degrees for group I and 30.0 degrees for group II (P =.23); C) 23.9 degrees for group I and 32.0 degrees for group II (P =.02); D) 7.8 cm for group I and 3.9 cm for group II (P <.001). CONCLUSIONS: Both techniques achieved the desired positioning for the femoral tunnel entrance and satisfactory thickness for the posterior cortex. Drilling via the anteromedial portal may provide greater protection against rupture of the posterior wall.

Positioning of the femoral tunnel for arthroscopic reconstruction of the anterior cruciate ligament: comparative study of 2 techniques

OBJECTIVE: To compare the accuracy of positioning of the femoral tunnel in reconstructing the anterior cruciate ligament by means of 2 techniques: tibial tunnel and anteromedial portal. METHOD: Femoral tunnels were drilled in 20 knees from human cadavers by means of arthroscopy. Group I had the femoral tunnel drilled via a trans-tibial tunnel, and Group II via the anteromedial portal. Four variables were measured: A) posterior wall thickness; B) tunnel positioning at the notch; C) tunnel inclination in relation to the femoral axis; and D) distance between the wire guide exit and the lateral epicondyle. RESULTS: As above, respectively, A) 2.23 mm for group I and 2.36 mm for group II (P =.54); B) 25.5° for group I and 30.0° for group II (P =.23); C) 23.9° for group I and 32.0° for group II (P =.02); D) 7.8 cm for group I and 3.9 cm for group II (P <.001). CONCLUSIONS: Both techniques achieved the desired positioning for the femoral tunnel entrance and satisfactory thickness for the posterior cortex. Drilling via the anteromedial portal may provide greater protection against rupture of the posterior wall.

OBJETIVO: Comparar a acurácia do posicionamento do túnel femoral na reconstrução do ligamento cruzado anterior através de duas vias: túnel tibial e portal ântero - medial. MÉTODO: Foram perfurados túneis femorais em vinte joelhos de cadáveres humanos por via artroscópica. Grupo I: túnel femoral por acesso trans túnel tibial. Grupo II: via portal ântero-medial. Quatro variáveis foram estudadas: A) espessura da parede posterior; B) posicionamento do túnel no intercôndilo; C) angulação do túnel em relação ao eixo do fêmur; D) distância entre a saída do fio guia e o epicôndilo lateral. RESULTADO: A) grupo I: 2,23 mm, grupo II: 2,36 mm (p=0,543); B) grupo I: 25,5°, grupo II: 30° (p=0,226); C) grupo I: 23,9°, grupo II: 32° (p= 0,014); D) grupo I: 7,8 cm, grupo II 3,9 cm (p<0,001). CONCLUSÃO: As duas técnicas obteveram o posicionamento desejado da entrada do túnel femoral e espessura adequada da cortical posterior. A perfuração via portal ântero-medial pode propiciar maior proteção contra rotura da parede posterior.

Estudo biomecânico de resistência à tração de âncoras metálicas de sutura em diferentes ângulos de inserção / Traction endurance biomechanical study of metallic suture anchors at differente insertion angles

The suture anchors' insertion angle and its traction resistance are the main subjects of this study. Twenty trials were realized using threaded suture anchors in four diferents angulations (30º /45º /60º /90º) in human bone (distal femur) and another twenty trials in artificial bone (SawboneTM). The anchors were pulled out being tractioned uprightly from its bone surface by a Kratos Universal test machine. The human bone results found no relation between the main subjects of this study, so whithout statistical value. On the other hand at the artificial bone the insertion angle of 90º beared more traction, being statistically significant compared to the other angles.

Osteotomia valgizante de tíbia com placa calço de Puddu combinada com a reconstrução do ligamento cruzado anterior do joelho / Valgus osteotomy of the tibia with a Puddu plate combined with anterior cruciate ligament reconstruction

Anterior knee instability associated with a varus deformity is a complex condition with several treatment possibilities. Among these, anterior cruciate ligament (ACL) associated to a simultaneous valgus tibial osteotomy is a increasing indication. This simultaneous procedure adds technical issues to those related to the isolated surgeries. Thus, the osteotomy plane and location of fixation hardware shouldnÆt conflict with tibial tunnel and ACL graft fixation. Authors analyze the relations between a opening tibial valgus osteotomy stabilized with a Puddu plate and ACL reconstruction with a patellar tendon graft fixated with interference screws in 10 human cadaver knees. A straight oblique tibial osteotomy starting on the medial tibial cortex and oriented laterally and proximally was performed on all knees with a 10mm opening medially and stabilized with a Puddu plate on the most posterior aspect of the medial tibia, and a tibial tunnel drilled 50° to tibial plateau. With this technique there was no intersection between tibial tunnel or interference screw and the osteotomy or the plate fixation screws.

Appraisal of surgical treatment of 47 cases of patellofemoral instability.

INTRODUCTION: Patellofemoral instability is a common knee disease. Its etiology is complex and variable, with many components making different contributions in each individual, resulting in several distinct clinical presentations. Our goal was to analyze the results of surgical treatment in our hospital over a period of 10 years. PATIENTS AND METHODS: We analyzed 55 knees of 47 patients who underwent surgery for patellofemoral instability and were classified into 2 main groups: proximal realignment and combined proximal and distal realignment. Three other groups were analyzed according to the duration of preoperative symptoms: less than 1 year (group I); 1 to 10 years (group II); and more than 10 years (group III). RESULTS: There were 62% good results overall, with 78% good results in groups I and II. Group III had 81% bad results, showing that a late diagnosis of advanced disease results in a poor prognosis. In addition to late diagnosis, bad results were usually associated with incorrect diagnosis or choice of surgical technique. There was no significant difference between isolated proximal realignment and combined proximal and distal realignment in groups I or II, but in group III, the combined technique yielded better results. DISCUSSION: Our results indicate that patellofemoral instability should be addressed in its early stages. Patients with long-lasting symptoms or more severe disease seem to achieve better results with combined techniques. CONCLUSION: Proximal and distal realignments produce better results than isolated proximal realignment in patients with joint degeneration or with greater duration of disease. The realignment surgery does not produce good results in patients with advanced disease.

Appraisal of surgical treatment of 47 cases of patellofemoral instability

INTRODUCTION: Patellofemoral instability is a common knee disease. Its etiology is complex and variable, with many components making different contributions in each individual, resulting in several distinct clinical presentations. Our goal was to analyze the results of surgical treatment in our hospital over a period of 10 years. PATIENTS AND METHODS: We analyzed 55 knees of 47 patients who underwent surgery for patellofemoral instability and were classified into 2 main groups: proximal realignment and combined proximal and distal realignment. Three other groups were analyzed according to the duration of preoperative symptoms: less than 1 year (group I); 1 to 10 years (group II); and more than 10 years (group III). RESULTS: There were 62 percent good results overall, with 78 percent good results in groups I and II. Group III had 81 percent bad results, showing that a late diagnosis of advanced disease results in a poor prognosis. In addition to late diagnosis, bad results were usually associated with incorrect diagnosis or choice of surgical technique. There was no significant difference between isolated proximal realignment and combined proximal and distal realignment in groups I or II, but in group III, the combined technique yielded better results. DISCUSSION: Our results indicate that patellofemoral instability should be addressed in its early stages. Patients with long-lasting symptoms or more severe disease seem to achieve better results with combined techniques. CONCLUSION: Proximal and distal realignments produce better results than isolated proximal realignment in patients with joint degeneration or with greater duration of disease. The realignment surgery does not produce good results in patients with advanced disease

Vacinação da gestante no pré-natal - revisão integrativa da literatura

O tétano e a hepatite B são doenças passíveis de imunização prévia e evitáveis. Com o intuito de zelar pelo cuidado da mãe e da prole o objetivo deste estudo é fazer uma revisão da literatura sobre a importância da adesão da gestante ao esquema vacinal, através de uma revisão integrativa. Utilizou-se de busca em banco de dados da BIREME com descritores pré-selecionados, resultando, inicialmente, na coleta de 224 estudos, onde os idiomas encontrados foram, Inglês (42,86%), Português (41,52%), Espanhol (12,94%), Francês (1,78%), Alemão e Húngaro (0,45% cada), a base de dados da LILACS contribuiu com 80,00% dos estudos. Após seleção e classificação de 12 estudos, os dados levantados foram, idioma Português (91,67%) e o ano de maior publicação ocorreu em 2008 (33,34%) seguido dos anos 2003 e 2009 (16,67% cada). Referente aos dados bibliográficos, 1 estudo (8,33%) menciona a eficácia da imunização da vacina anti-tetânica na gestação através de testes laboratoriais; 4 estudos (33,34%) se relacionam à avaliação da cobertura da vacina anti-tetânica em gestantes com taxas de imunizações variando entre 33,5% a 100% e oportunidades de imunizações perdidas em 70% no município de Juiz de Fora - MG; e 7 estudos (58,33%) fazem referências as Hepatites Virais, sendo que 6 estudos citam a taxa de HBsAg encontradas nas gestantes triadas no pré-natal, oscilando entre 0,3% a 8,7% em várias regiões do Brasil e 1 estudo menciona o conhecimento dos obstetras frente as condutas contra a hepatite na gestação. Concluí-se que as taxas de vacinação anti-tetânica, não atingem nem a metade preconizada pelo Ministério da Saúde e que há necessidade de implantar a vacina contra hepatite B e de realizar a sorologia para o vírus da hepatite B nas gestantes, com a finalidade de evitar a transmissão vertical da doença, como é sugerido na nota técnica do Ministério da Saúde (ANEXO - A).

Toxoplasmose na gestação: proposta de intervenção

A Estratégia da Saúde da Família deve estimular e desenvolver as ações da equipe de saúde em consonância com os princípios do Sistema Único de Saúde, com vistas à promoção, proteção e recuperação da saúde, tanto no âmbito individual quanto no coletivo e evidencia a família como foco primordial da ação. Tendo em vista que a toxoplasmose na gestação pode acarretar sérios danos ao recém-nascido, este estudo tem como objetivo elaborar uma proposta de intervenção na Estratégia de Saúde da Família Cândido Bernardes, município de Monte Belo, Minas Gerais, para a implantação da prática educativa, por meio de grupo operativo, para a atuação da equipe de saúde na promoção à saúde, na prevenção da toxoplasmose congênita. Esta proposta de intervenção por meio de grupos operativos visa ao estabelecimento de uma nova concepção pedagógica para os profissionais e para a comunidade que resultará em articulação entre profissional e usuários do sistema, redução das taxas de toxoplasmose na gestação, minimizando problemas de saúde na criança em consequência desta infecção parasitária; a melhoria das ações às mulheres, principalmente, em idade fértil, pois é durante esse período que ocorre a gestação, bem como um planejamento familiar condizente com a realidade de cada mulher