Avaliação dos Efeitos da Remoção da Resina Residual e do Polimento na Superfície do Esmalte após Descolagem do Braquete / Evaluation of the Effects of Residual Resin Removal and Polishing on the Enamel Surface after Bracket Debonding

Considerando o uso de brocas para remoção da resina residual após descolagem do braquete e a possibilidade de injúrias à superfície do esmalte após o uso dessas brocas, este trabalho teve como objetivo realizar um estudo experimental, para avaliar a variação do aspecto superficial do esmalte de forma qualitativa, por meio da avaliação com imagens topográficas do esmalte dentário, utilizando-se a Microscopia Eletrônica de Varredura (MEV), a qual permitiu ilustrar e avaliar a superfície do esmalte após a fase de polimento final, realizada por dois métodos: taça de borracha ou escova Robinson. Foram utilizados 25 dentes pré-molares humanos, obtidos a partir de exodontias em pacientes que procuraram voluntariamente o curso de Residência em Cirurgia da Clínica Odontológica Universitária da Universidade Estadual de Londrina. Os dentes foram divididos em quatro grupos: A, B, C e D, contendo 6 dentes cada, de acordo com as brocas utilizadas para a remoção do remanescente adesivo e o polimento escolhido, além de um dente como "controle". Foi avaliada a rugosidade superficial do esmalte após a remoção da resina e a superfície do esmalte após o polimento com as duas opções apresentadas. Os resultados mostraram que, por observação e inspeção, as brocas removeram a resina residual de todos os dentes, porém, causaram riscos e ranhuras, como evidenciado nas imagens em MEV. Concluiu-se que não houve diferença estatística entre os métodos de polimento e que ambos foram importantes para a redução das marcas abrasivas, proporcionando uma superfície mais lisa do esmalte.

Considering the use of specific burs to remove residual resin after bracket debonding and the possibility of injuries to the dental enamel after using these burs, this study aimed to verify the variation in the enamel surface appearance in a qualitative way and evaluation with topographic images of the dental enamel. The use of Scanning Electron Microscopy (SEM) allowed to illustrate and evaluate the enamel surface after the final polishing phase using two methods: rubber cup or Robinson brush. Twenty-five human premolar teeth were obtained from extractions in patients who voluntarily sought the Oral Maxillofacial Surgery Residency at the Dental School from the State University of Londrina; the teeth were divided into four groups A, B, C and D containing 6 teeth each according to the burs used to remove the remaining adhesive and the chosen polishing, in addition to one tooth as a "control". Dental enamel surface roughness was evaluated after resin removal and enamel surface after polishing with the two methods presented. The results showed that by observation and inspection, the burs removed residual resin from all teeth, however, caused scratches and grooves as evidenced in the SEM images. Based on the results, there was no statistical difference between the polishing methods, and both were important for the reduction of abrasive marks and provided a smoother enamel surface.

RT-qPCR-based pool testing for the diagnosis of COVID-19.

This study proposes a strategy for large-scale testing among a large number of people for the early diagnosis of COVID-19 to elucidate the epidemiological situation. Pool testing involves the analysis of pooled samples. This study aimed to discuss a reverse transcription technique followed by quantitative real-time polymerase chain reaction using pool testing to detect SARS-CoV-2 in nasopharyngeal swab samples. The study proposes an innovative diagnostic strategy that contributes to resource optimization, cost reduction, and improved agility of feedback from results. Pool testing is simultaneously performed on multiple samples to efficiently and cost-effectively detect COVID-19. Pool testing can optimize resource utilization and expand diagnostic access, and is a viable alternative for developing countries with limited access to testing. To optimize resources, the pool size was determined by estimating COVID-19 prevalence in the study population.

Contributions to Dynamic Analysis of Differential Evolution Algorithms.

The Differential Evolution (DE) algorithm is one of the most successful evolutionary computation techniques. However, its structure is not trivially translatable in terms of mathematical transformations that describe its population dynamics. In this work, analytical expressions are developed for the probability of enhancement of individuals after each application of a mutation operator followed by a crossover operation, assuming a population distributed radially around the optimum for the sphere objective function, considering the DE/rand/1/bin and the DE/rand/1/exp algorithm versions. These expressions are validated by numerical experiments. Considering quadratic functions given by f(x)=xTDTDx and populations distributed according to the linear transformation D-1 of a radially distributed population, it is also shown that the expressions still hold in the cases when f(x) is separable (D is diagonal) and when D is any nonsingular matrix and the crossover rate is Cr=1.0. The expressions are employed for the analysis of DE population dynamics. The analysis is extended to more complex situations, reaching rather precise predictions of the effect of problem dimension and of the choice of algorithm parameters.

RT-qPCR-based pool testing for the diagnosis of COVID-19

ABSTRACT This study proposes a strategy for large-scale testing among a large number of people for the early diagnosis of COVID-19 to elucidate the epidemiological situation. Pool testing involves the analysis of pooled samples. This study aimed to discuss a reverse transcription technique followed by quantitative real-time polymerase chain reaction using pool testing to detect SARS-CoV-2 in nasopharyngeal swab samples. The study proposes an innovative diagnostic strategy that contributes to resource optimization, cost reduction, and improved agility of feedback from results.

Self-collected nasopharyngeal swab and molecular test using pool testing as strategies to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): feasibility in medical students at the Universidade Federal de Minas Gerais, Brazil, 2021. / Autocoleta de swab nasofaríngeo e teste molecular em pool testing como estratégias para detecção de coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2): viabilidade em estudantes de medicina da Universidade Federal de Minas Gerais, 2021.

OBJECTIVE: To show the feasibility of the combined use of self-collected nasopharyngeal swab and pool testing to detect SARS-CoV-2 in epidemiological surveys. METHODS: This experience included a sample of 154 students at the Universidade Federal de Minas Gerais, who performed self-collected nasopharyngeal swab in individual cabins and without supervision. The molecular test was performed using the pool testing technique. RESULTS: It took each person 5 minutes to collect the sample. An analysis was performed to detect endogenous RNA in 40 samples. The results showed that there were no failures resulting from self-collection. None of the pools detected the presence of viral RNA. The cost of molecular testing (RT-PCR), by pool testing, with samples obtained by self-collection was about ten times lower than the usual methods. CONCLUSION: The strategies that were investigated proved to be economically feasible and valid for the research on SARS-CoV-2 in epidemiological surveys.

SARS-CoV-2 IgG Seroprevalence among Blood Donors as a Monitor of the COVID-19 Epidemic, Brazil.

During epidemics, data from different sources can provide information on varying aspects of the epidemic process. Serology-based epidemiologic surveys could be used to compose a consistent epidemic scenario. We assessed the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG in serum samples collected from 7,837 blood donors in 7 cities of Brazil during March-December 2020. Based on our results, we propose a modification in a compartmental model that uses reported number of SARS-CoV-2 cases and serology results from blood donors as inputs and delivers estimates of hidden variables, such as daily values of SARS-CoV-2 transmission rates and cumulative incidence rate of reported and unreported SARS-CoV-2 cases. We concluded that the information about cumulative incidence of a disease in a city's population can be obtained by testing serum samples collected from blood donors. Our proposed method also can be extended to surveillance of other infectious diseases.

Self-collection of nasopharyngeal swab and molecular test in pool testing as strategies for detecting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): feasibility in medical students at the Universidade Federal de Minas Gerais, 2021 / Autocollección de swabs nasofaríngeos y pruebas moleculares en pool testing como estrategias para la detección del Coronavirus Síndrome Respiratorio Agudo Severo 2 (SARS-CoV-2): viabilidad en estudiantes de medicina de la Universidade Federal de Minas Gerais, 2021 / Autocoleta de swab nasofaríngeo e teste molecular em pool testing como estratégias para detecção de coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2): viabilidade em estudantes de medicina da Universidade Federal de Minas Gerais, 2021

Objective: To show the feasibility of using combined nasopharyngeal swab auto-collection and pool testing to detect SARS-CoV-2 in epidemiological surveys. Methods: The study involved a sample of 154 students from the Universidade Federal de Minas Gerais, who performed the self-collection of the nasopharyngeal swab in individual booths without supervision. Molecular testing was performed using the pool testing technique. Results: Obtaining samples lasted about 5 minutes each. Analysis 6 was performed to detect endogenous RNA in 40 samples, and the results indicated that no failures resulted from self-collection. None of the pools detected the presence of viral RNA. The cost of performing the molecular test (RT-PCR) by pool testing with samples obtained by self-collection was about 10 times lower than with the usual methods. Conclusion: The investigated strategies showed to be economically feasible and valid for the research of SARS-CoV-2 in epidemiological surveys.

Objetivo: Demostrar la viabilidad de utilizar el uso combinado de la autocollección de swabs nasofaríngeos y pool testing para la detección del SARS-CoV2 en encuestas epidemiológicas. Métodos: El estudio involucró a una muestra de 154 estudiantes de la Universidade Federal de Minas Gerais, quienes realizaron la autocolección del hisopo nasofaríngeo en cabinas individuales sin supervision. La prueba molecular se realizó utilizando la técnica de prueba de grupo. Resultados: La obtención de muestras duró unos 5 minutos por persona. Se realizó un análisis para detectar RNA endógeno en 40 muestras y los resultados indicaron que no hubo fallas derivadas de la autocolección. Ninguno de los grupos detectó la presencia de RNA viral. El costo de realizar una prueba molecular (RT-PCR) por pool con muestras obtenidas por auto-recolección fue aproximadamente 10 veces menor que con los métodos habituales. Conclusión: Las estrategias investigadas demonstraram ser económicamente viables y válidas para la investigación del SARS-CoV-2 en encuestas epidemiológicas.

Objetivo: Demonstrar a viabilidade da utilização combinada da autocoleta de swab nasofaríngeo e pool testing para detecção do SARS-CoV-2 em inquéritos epidemiológicos. Métodos: O estudo envolveu amostra de 154 estudantes da Universidade Federal de Minas Gerais, que realizaram a autocoleta do swab nasofaríngeo em cabines individuais e sem supervisão. O teste molecular foi realizado utilizando-se a técnica de pool testing. Resultados: A obtenção de amostras durou cerca de 5 minutos por pessoa. Realizou-se análise para detecção de RNA endógeno em 40 amostras e os resultados indicaram que não houve falhas decorrentes da autocoleta. Nenhum dos pools detectou presença de RNA viral. O custo da realização do teste molecular (RT-PCR) por pool testing com amostras obtidas por autocoleta foi cerca de dez vezes menor do que nos métodos habituais. Conclusão: As estratégias investigadas mostraram-se economicamente viáveis e válidas para a pesquisa de SARS-CoV-2 em inquéritos epidemiológicos.

Autocoleta de swab nasofaríngeo e teste molecular em pool testing como estratégias para detecção de coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2): viabilidade em estudantes de medicina da Universidade Federal de Minas Gerais, 2021 / Autocolección de hiopados nasofaríngeos y pruebas moleculares en pool testing como estrategias para la detección del Coronavirus Síndrome Respiratorio Agudo Severo 2 (SARS-CoV-2): viabilidad en estudiantes de medicina de la Universidad Federal de Minas Gerais, Brasil, 2021 / Self-collected nasopharyngeal swab and molecular test using pool testing as strategies to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): feasibility in medical students at the Universidade Federal de Minas Gerais, Brazil, 2021

Objetivo: Demonstrar a viabilidade da utilização combinada da autocoleta de swab nasofaríngeo e pool testing para detecção do SARS-CoV-2 em inquéritos epidemiológicos. Métodos: A experiência envolveu amostra de 154 estudantes da Universidade Federal de Minas Gerais, que realizaram a autocoleta do swab nasofaríngeo em cabines individuais e sem supervisão. O teste molecular foi realizado utilizando-se a técnica de pool testing. Resultados: A obtenção de amostras durou cerca de 5 minutos por pessoa. Realizou-se análise para detecção de RNA endógeno em 40 amostras e os resultados indicaram que não houve falhas decorrentes da autocoleta. Nenhum dos pools detectou presença de RNA viral. O custo da realização do teste molecular (RT-PCR) por pool testing com amostras obtidas por autocoleta foi cerca de dez vezes menor do que nos métodos habituais. Conclusão: As estratégias investigadas mostraram-se economicamente viáveis e válidas para a pesquisa de SARS-CoV-2 em inquéritos epidemiológicos.

Objetivo: Demostrar la viabilidad del uso combinado de la auto recolección de swabs nasofaríngeos y tests por agrupamiento (pool testing) para la detección del SARS-CoV-2 en encuestas epidemiológicas. Métodos: La prueba involucró a una muestra de 154 estudiantes de la Universidade Federal de Minas Gerais, quienes realizaron e autorecolectado del hisopo nasofaríngeo en cabinas individuales sin supervisión. La prueba molecular se realizó utilizando la técnica de prueba de grupo. Resultados: La obtención de muestras duró unos 5 minutos por persona. Se realizó un análisis para detectar ARN endógeno en 40 muestras y los resultados indicaron que no hubo fallas derivadas de la autorecolección. Ninguno de los grupos detectó la presencia de ARN viral. El costo de realizar una prueba molecular (RT-PCR) por pool con muestras obtenidas por auto-recolección fue aproximadamente 10 veces menor que con los métodos habituales. Conclusión: Las estrategias investigadas demostraron ser económicamente viables y válidas para la investigación del SARS-CoV-2 en encuestas epidemiológicas.

Objective: To show the feasibility of the combined use of self-collected nasopharyngeal swab and pool testing to detect SARS-CoV-2 in epidemiological surveys. Methods: This experience included a sample of 154 students at the Universidade Federal de Minas Gerais, who performed self-collected nasopharyngeal swab in individual cabins and without supervision. The molecular test was performed using the pool testing technique. Results: It took each person 5 minutes to collect the sample. An analysis was performed to detect endogenous RNA in 40 samples. The results showed that there were no failures resulting from self-collection. None of the pools detected the presence of viral RNA. The cost of molecular testing (RT-PCR), by pool testing, with samples obtained by self-collection was about ten times lower than the usual methods. Conclusion: The strategies that were investigated proved to be economically feasible and valid for the research on SARS-CoV-2 in epidemiological surveys.

Detection of SARS-CoV-2 through pool testing for COVID-19: an integrative review.

INTRODUCTION: The pool testing technique optimizes the number of tests performed and reduces the delivery time of results, which is an interesting strategy for the health crisis caused by the COVID-19 pandemic. This integrative review investigated studies in which pool testing was carried out for epidemiological or screening purposes to analyze its clinical or cost effectiveness and assessed the applicability of this method in high-, middle-, and low-income countries. METHODS: This integrative review used primary studies published in the MEDLINE, EMBASE, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), and Cochrane Library databases. RESULTS: A total of 435 studies were identified: 35.3% were carried out in Asia, 29.4% in Europe, 29.4% in North America, and 5.9% in Oceania. CONCLUSIONS: This review suggests that pool testing in the general population may be a useful surveillance strategy to detect new variants of SARS-CoV-2 and to evaluate the period of immunogenicity and global immunity from vaccines.

Application of Optimal Control of Infectious Diseases in a Model-Free Scenario.

Optimal control for infectious diseases has received increasing attention over the past few decades. In general, a combination of cost state variables and control effort have been applied as cost indices. Many important results have been reported. Nevertheless, it seems that the interpretation of the optimal control law for an epidemic system has received less attention. In this paper, we have applied Pontryagin's maximum principle to develop an optimal control law to minimize the number of infected individuals and the vaccination rate. We have adopted the compartmental model SIR to test our technique. We have shown that the proposed control law can give some insights to develop a control strategy in a model-free scenario. Numerical examples show a reduction of 50% in the number of infected individuals when compared with constant vaccination. There is not always a prior knowledge of the number of susceptible, infected, and recovered individuals required to formulate and solve the optimal control problem. In a model-free scenario, a strategy based on the analytic function is proposed, where prior knowledge of the scenario is not necessary. This insight can also be useful after the development of a vaccine to COVID-19, since it shows that a fast and general cover of vaccine worldwide can minimize the number of infected, and consequently the number of deaths. The considered approach is capable of eradicating the disease faster than a constant vaccination control method.

Adjusting the Cut-Off and Maximum Pool Size in RT-qPCR Pool Testing for SARS-CoV-2.

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) to detect SARS-CoV-2 RNA is an essential test to monitor the occurrence of COVID-19. A methodology is proposed for the determination of maximum pool size and adjustments of cut-off values of cycle threshold (Ct in RT-qPCR pool testing, to compensate for the dilution caused by pooling. The trade-off between pool size and test sensitivity is stated explicitly. The procedure was designed to ensure that samples that would be detectable in individual testing remain detectable in pool testing. The proposed relaxation in cut-off is dependent on the pool size, allowing a relatively tight correction to avoid loss of detection of positive samples. The methodology was evaluated in a study of pool testing of adults attending a public emergency care unit, reference for COVID-19 in Belo Horizonte, Brazil, and presenting flu-like symptoms. Even samples on the edge of detectability in individual testing were detected correctly. The proposed procedure enhances the consistency of RT-qPCR pool testing by enforcing that the scales of detectability in pool processing and in individual sample processing are compatible. This may enhance the contribution of pool testing to large-scale testing for COVID-19.

Comparing community mobility reduction between first and second COVID-19 waves.

Background: In this paper, we conduct a mobility reduction rate comparison between the first and second COVID-19 waves in several localities from America and Europe using Google community mobility reports (CMR) data. Through multi-dimensional visualization, we are able to compare the reduction in mobility from the different lockdown periods for each locality selected, simultaneously considering multiple place categories provided in CMR. In addition, our analysis comprises a 56-day lockdown period for each locality and COVID-19 wave, which we analyze both as 56-day periods and as 14-day consecutive windows. Methods: We use locality-wise calibrated CMR data, which we process through seasonal-trend decomposition by LOESS (STL) to isolate trend from seasonal and noise effects. We scale trend data to draw Pareto-compliant conclusions using radar charts. For each temporal granularity considered, data for a given place category is aggregated using the area under the curve (AUC) approach. Results: In general, reduction rates observed during the first wave were much higher than during the second. Alarmingly, December holiday season mobility in some of the localities reached pre-pandemic levels for some of the place categories reported. Manaus was the only locality where second wave mobility was nearly as reduced as during the first wave, likely due to the P1 variant outbreak and oxygen supply crisis.

Detection of SARS-CoV-2 through pool testing for COVID-19: an integrative review

Abstract INTRODUCTION: The pool testing technique optimizes the number of tests performed and reduces the delivery time of results, which is an interesting strategy for the health crisis caused by the COVID-19 pandemic. This integrative review investigated studies in which pool testing was carried out for epidemiological or screening purposes to analyze its clinical or cost effectiveness and assessed the applicability of this method in high-, middle-, and low-income countries. METHODS: This integrative review used primary studies published in the MEDLINE, EMBASE, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), and Cochrane Library databases. RESULTS: A total of 435 studies were identified: 35.3% were carried out in Asia, 29.4% in Europe, 29.4% in North America, and 5.9% in Oceania. CONCLUSIONS: This review suggests that pool testing in the general population may be a useful surveillance strategy to detect new variants of SARS-CoV-2 and to evaluate the period of immunogenicity and global immunity from vaccines.

Vertical social distancing policy is ineffective to contain the COVID-19 pandemic.

Considering numerical simulations, this study shows that the so-called vertical social distancing health policy is ineffective to contain the COVID-19 pandemic. We present the SEIR-Net model, for a network of social group interactions, as a development of the classic mathematical model of SEIR epidemics (Susceptible-Exposed-Infected (symptomatic and asymptomatic)-Removed). In the SEIR-Net model, we can simulate social contacts between groups divided by age groups and analyze different strategies of social distancing. In the vertical distancing policy, only older people are distanced, whereas in the horizontal distancing policy all age groups adhere to social distancing. These two scenarios are compared to a control scenario in which no intervention is made to distance people. The vertical distancing scenario is almost as bad as the control, both in terms of people infected and in the acceleration of cases. On the other hand, horizontal distancing, if applied with the same intensity in all age groups, significantly reduces the total infected people "flattening the disease growth curve". Our analysis considers the city of Belo Horizonte, Minas Gerais State, Brazil, but similar conclusions apply to other cities as well. Code implementation of the model in R-language is provided in the supplementary material.

Widespread Sporadic Type Burkitt Lymphoma Presenting as Dental Mobility and Premature Eruption of Permanent Teeth in a Child.

Burkitt lymphoma (BL) is a rare and aggressive malignant neoplasm frequently involving the jawbones in children. The main purpose of this article is to report the case of a nine-year-old boy with widespread BL diagnosed through oral findings. The patient was referred after complaining of dental mobility for two weeks. The physical examination revealed premature eruption of permanent teeth. The periapical radiographic examination showed a diffuse bone rarefaction in the involved area. An incisional biopsy was performed, leading to the diagnosis of BL. The patient was then treated with chemotherapy and is free of disease after an 18-month follow-up. The main signs and symptoms of an oral BL could mimic a dental problem, thus it is extremely important to be knowledgeable about this disease, which can be fatal without early diagnosis and treatment.

Microstructural effect of a laser-activated bleaching agent containing titanium dioxide on human enamel.

AIM: This study aimed to evaluate the effect of a laser-activated bleaching agent containing titanium dioxide (TiO2) nanoparticles on enamel roughness and hardness. MATERIALS AND METHODS: Twenty human premolars were randomized into two groups according to the bleaching treatments performed: HP - 35% hydrogen peroxide and HP + TiO2 - 30% hydrogen peroxide containing TiO2 light-activated by diode laser (980 nm). It was performed two bleaching sessions with an interval of 7 days. Microhardness and roughness of the enamel were assessed at three times: T0 - Before 1st appointment, T1 - after 2nd appointment, and T2-7 days after 2nd appointment. RESULTS: The HP + TiO2 did not cause changes on enamel roughness and hardness and presented the same effects of the HP. CONCLUSIONS: Both bleaching agents showed no difference between them. Then, it is possible to conclude that both are viable for clinical use during in-office dental bleaching technique regarding the microstructural changes that they might cause.

Vertical social distancing policy is ineffective to contain the COVID-19 pandemic / A política de distanciamento social vertical é ineficaz para conter a pandemia da COVID-19 / La política de aislamiento social vertical es ineficaz para contener la pandemia de COVID-19

Abstract: Considering numerical simulations, this study shows that the so-called vertical social distancing health policy is ineffective to contain the COVID-19 pandemic. We present the SEIR-Net model, for a network of social group interactions, as a development of the classic mathematical model of SEIR epidemics (Susceptible-Exposed-Infected (symptomatic and asymptomatic)-Removed). In the SEIR-Net model, we can simulate social contacts between groups divided by age groups and analyze different strategies of social distancing. In the vertical distancing policy, only older people are distanced, whereas in the horizontal distancing policy all age groups adhere to social distancing. These two scenarios are compared to a control scenario in which no intervention is made to distance people. The vertical distancing scenario is almost as bad as the control, both in terms of people infected and in the acceleration of cases. On the other hand, horizontal distancing, if applied with the same intensity in all age groups, significantly reduces the total infected people "flattening the disease growth curve". Our analysis considers the city of Belo Horizonte, Minas Gerais State, Brazil, but similar conclusions apply to other cities as well. Code implementation of the model in R-language is provided in the supplementary material.

Resumo: O artigo demonstra através de simulações numéricas que a política do chamado distanciamento social vertical é ineficaz para conter a pandemia da COVID-19. Os autores apresentam o modelo SEIR-Net para uma rede de interações entre grupos sociais, enquanto desdobramento do modelo matemático clássico para epidemias, chamado SEIR (Suscetíveis-Expostos-Infectados (sintomáticos e assintomáticos)-Removidos). No modelo SEIR-Net, pode-se simular contatos sociais entre grupos, divididos por faixas etárias, e analisar diferentes estratégias de distanciamento social. Na política de distanciamento vertical, apenas os idosos ficam distanciados, ao contrário da política de distanciamento horizontal, em que todas as faixas etárias aderem ao distanciamento. O artigo compara esses dois cenários a um cenário controle, sem nenhuma intervenção para distanciar as pessoas umas das outras. O cenário do distanciamento vertical é quase tão ruim quanto aquele sem nenhum distanciamento, em termos tanto do número de infectados quanto da aceleração do número de casos. Por outro lado, o distanciamento horizontal, desde que aplicado com a mesma intensidade a todos os grupos etários, reduz significativamente o número total de infectados e "achata a curva de crescimento da doença". Nossa análise foi feita no Município de Belo Horizonte, Minas Gerais, Brasil, mas conclusões semelhantes se aplicam igualmente a outras cidades. O material suplementar do artigo fornece detalhes sobre a implementação do código do modelo na linguagem R.

Demostramos mediante simulaciones numéricas que la denominada política de salud de aislamiento social vertical es ineficaz para contener la pandemia de COVID-19. Presentamos el modelo SEIR-Net para interacciones de grupo en una red social, como una evolución del clásico modelo matemático SEIR epidemics (Susceptibles-Expuestos-Infectados (sintomáticos y asintomáticos)-Removidos). En el modelo SEIR-Net, podemos simular contactos sociales entre grupos divididos por grupos de edad y analizar diferentes estrategias de distanciamiento social. En la política de aislamiento vertical, solamente se aísla a los ancianos, frente a la política de aislamiento horizontal, donde todos los grupos de edad se adhieren al aislamiento social. Estos dos escenarios se compararon a un escenario de control, en el que no se realiza ninguna intervención para aislar a la gente. El escenario de aislamiento vertical es casi tan malo, como el escenario donde no se aplica ningún tipo de aislamiento, tanto en términos del número de infectados, como en la aceleración del número de casos. Por otro lado, el aislamiento horizontal, si se aplica con la misma intensidad en todos los grupos de edad, reduce significativamente el número total de infectados y "aplana la curva de crecimiento de la enfermedad". Nuestro análisis se realiza en la municipalidad de Belo Horizonte, Minas Gerais, Brasil, pero conclusiones similares se pueden aplicar también a otras ciudades. En el material complementario se facilita la implementación del código del modelo en R-language.

Kinesio taping to generate skin convolutions is not better than sham taping for people with chronic non-specific low back pain: a randomised trial.

QUESTION: For people with chronic low back pain, does Kinesio Taping, applied according to the treatment manual to create skin convolutions, reduce pain and disability more than a simple application without convolutions? DESIGN: Randomised trial with concealed allocation, intention-to-treat analysis and blinded assessment of some outcomes. PARTICIPANTS: 148 participants with chronic non-specific low back pain. INTERVENTION: Experimental group participants received eight sessions (over four weeks) of Kinesio Taping applied according to the Kinesio Taping Method treatment manual (ie, 10 to 15% tension applied in flexion to create skin convolutions in neutral). Control group participants received eight sessions (over four weeks) of Kinesio Taping with no tension, creating no convolutions. OUTCOME MEASURES: The primary outcome measures were pain intensity and disability after the four-week intervention. Secondary outcomes were pain intensity and disability 12 weeks after randomisation, and global perceived effect at both four and 12 weeks after randomisation. RESULTS: Applying Kinesio Tape to create convolutions in the skin did not significantly change its effect on pain (MD-0.4 points, 95% CI-1.3 to 0.4) or disability (MD-0.3 points, 95% CI-1.9 to 1.3) at four weeks. There was a small difference in favour of the experimental group for the secondary outcome of global perceived effect (MD 1.4 points, 95% CI 0.3 to 2.5) at four weeks. No significant between-group differences were observed for the other secondary outcomes. CONCLUSION: Kinesio Taping applied with stretch to generate convolutions in the skin was no more effective than simple application of the tape without tension for the outcomes measured. These results challenge the proposed mechanism of action of this therapy. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials, RBR-7ggfkv.

Avaliação da estética do perfil facial tegumentar baseada no posicionamento do lábio inferior / Evaluation aesthetics of soft-tissue facial profile based on positioning of the lower lip

O objetivo do trabalho foi avaliar e comparar as semelhançase diferenças na preferência da posição do lábio inferior em perfisfaciais masculinos e femininos, e determinar quando - considerandoo número de milímetros de protrusão ou retrusão do lábio inferior -os perfis não são mais considerados estéticos, quando avaliadas porortodontistas, cirurgiões-dentistas e leigos. Os perfis faciais de jovensadultos, um masculino e outro feminino, considerados estéticos eharmônicos, foram selecionados e fotografados. Com base nas fotos,silhuetas foram criadas e modificadas com uma protrusão e retrusãosequencial de 2 mm do lábio inferior. As silhuetas foram, então, colocadasjunto às silhuetas originais em fichas de avaliação, que foramdistribuídas para os três grupos de avaliadores. Os avaliadores foramsolicitados a classificar os perfis como estético ou não estético. Osortodontistas e cirurgiões-dentistas escolheram os perfis, para ambosos sexos, com a posição dos lábios de acordo com o proposto pelaliteratura, tolerando apenas uma retrusão de até 2 mm. Os avaliadoresleigos, no entanto, foram mais tolerantes, aceitando uma protrusão ouretrusão no perfil masculino de até 2 mm, e no feminino uma retrusão deaté 4 mm, e nenhuma protrusão. Os três grupos de avaliadores forammais tolerantes à retrusão do lábio inferior do que à sua protrusão,tanto para o perfil masculino como para o feminino. Além disso, osavaliadores leigos foram menos críticos sobre o número de milímetrosde protrusão e retrusão do lábio inferior, aceito como estético.

The objective are evaluate and compare the similaritiesand differences in preference of the position of the lower lip in a maleand in a female facial profile, and to determinate when, consideringthe number of millimeters of the lower lip's protrusion ar retrusion,the profiles are no longer considered as aesthetic when evaluatedby orthodontists, dental surgeons and lay people. One male and onefemale young adult facial profiles, considered aesthetic and harmonic,were selected and photographed. Based on the photos, silhouetteswere created and were modified in a 2 mm sequential protrusionand sequential retrusion of the lower lip. The silhouettes were thenput together with the original ones on evaluation sheets, which weredistributed to the three groups of evaluators. The evaluators wereask.ed to classify the profiles as aesthetic, it means, beautiful, ar notaesthetic, it means, ugly. The orthodontists and the dental surgeonschose the profiles, for both genders, with the lip position accordingto that proposed by literature, tolerating only a retrusion up to 2 mm.The lay evaluators, however, were more tolerant, accepting a maleprotrusion and a retrusion up to 2 mm, and a female retrusion up to4 mm and no protrusion. The three groups of evaluators were moretolerant to the lower lip's retrusion than to its protrusion, both for themale and the female profiles. In addition, the lay evaluators were lesscritical about the number of millimeters of the lower lip's protrusion andretrusion accepted as aesthetic.

Deformation of elastomeric chains related to the amount and time of stretching.

OBJECTIVE: To investigate a potential relationship between degree of stretching and resulting permanent deformation of elastomeric chains (ECs) as well as whether or not stretching time has any bearing on the degree of permanent deformation. METHODS: Five-module segments of closed elastomeric chains manufactured by 3M Unitek were stretched to 10-100% of their original length in devices especially designed for this purpose, remaining submerged in artificial saliva at 37 ± 1° C and were removed sequentially after 1, 2, 3 and 4 weeks. Upon removal, each segment was measured and, once recorded the values, were statistically analyzed with the purpose of assessing the degree of permanent deformation. CONCLUSIONS: It was concluded that permanent deformation is directly proportional to the degree of stretching of the ECs assessed. The mean percentages found were 8.4% to 10% of stretching, and exceeding 20% (21.3%) when stretched by 40%, and reaching 56.6% permanent deformation when stretched 100% of their original length. Finally, the highest percentage of permanent deformation occurred during the first week and was not statistically significant after this period.