Abstract This study is based on the numerical simulation of the mechanical response of yttrium-stabilized zirconia ceramic (3Y-TZP) dental implants as a function of their intrinsic geometry and masticatory loads. Samples (n=20) of 3Y-TZP ceramics were compacted, sintered at 1500 °C - 2h, and characterized by relative density, X-Ray diffraction (XRD), and scanning electron microscopy (SEM). The elastic parameters (modulus of elasticity and Poisson ratio), used in the numerical simulations, were measured by the Impulse Excitation Technique, and the bending strength was obtained using piston-on-three-balls testing. An authorial implant design and, comparatively, commercial implant CAD models were used in this study as an initial geometry of dental implant in a typical adult mandible anatomy. From CAD and CAE techniques, finite element models were generated for all implant geometries. Loading cases were considered based on different intensities (100N to 500N) and orientation angles (45° or 90°) to reproduce the human masticatory efforts. The numerical predictions were compared with finite element simulations of gold-standard titanium-based implants. The investigated 3Y-TZP sintered ceramics presented high densification (> 99%), with a microstructure formed by submicron equiaxed tetragonal zirconia grains. The 3Y-TZP average bending strength obtained from piston-on-three-balls testing is 1192 ± 99 MPa. For both dental implant geometries, the zirconia implants showed average strength of less than 550 MPa, which, in turn, is independent of the masticatory load value or orientation angle. All finite element predictions are 50% inferior to the corresponding measured flexural strength values and preliminarily enable the 3Y-TZP ceramics for dental implant applications without fracture risk.

RESUMO Nos últimos anos, vários estudos foram realizados buscando reduzir o peso de veículos automotores, a fim de diminuir as emissões de poluentes. Neste cenário os aços de baixa densidade do sistema Fe-Mn-Al-C podem ser considerados uma alternativa promissora para suprir essas exigências da indústria automotiva. Geralmente, nos aços de baixa densidade, uma quantidade considerável de alumínio é adicionada a fim de reduzir a densidade geral do aço. No entanto, altos teores de alumínio promovem características distintas na microestrutura, destes aços quando comparados aos aços convencionais, como a presença do carboneto k ((Fe, Mn)3AlC), além da necessidade de se entender a combinação deste elemento com outros elementos de liga que podem ser adicionados. Neste contexto, este trabalho tem como objetivo avaliar a microestrutura, a dureza e a densidade resultantes em função da influência do Al e do Nb em uma nova composição química pertencente ao sistema Fe-Mn-Al-C, na condição trabalhada a quente, a partir de análises de difração de raios X, microscopia eletrônica, medidas de dureza e densidade por princípio de Arquimedes. Os resultados permitiram indicar que o alto teor de Al adicionado promoveu uma redução de cerca de 13% na densidade, em relação aos aços estruturais tradicionais, e a estabilidade da ferrita δ até a temperatura ambiente. A condição avaliada apresentou a temperatura ambiente uma microestrutura formada por uma matriz de ferrita δ e α, juntamente com precipitados de carboneto k (AlFe3C) e carboneto de nióbio (NbC), estes dois últimos devido as adições de Al e Nb, resultando em uma dureza de 59,4 ± 1 HRA e uma estimativa do limite de resistência a tração de próximo a 800 MPa – dentro da faixa dos aços avançados de alta resistência (Advanced High Strenght Steels – AHSS).

ABSTRACT In recent years, several studies have been carried out seeking to reduce the weight of motor vehicles to reduce pollutant emissions. In this scenario, low-density steels from the Fe-Mn-Al-C system can be considered a promising alternative to meet these requirements of the automotive industry. Generally, in low-density steel, a considerable aluminum amount is added in order to reduce the overall density of the steel. However, high aluminum contents promote distinct characteristics in the microstructure of these steels when compared to conventional steels, such as the k carbide presence ((Fe,Mn)3AlC), in addition to the need to understand the combination of this element with other alloying elements that can be added. In this context, this paper aims to evaluate the resulting microstructure, hardness and density as a function of the Al and Nb influence in a new chemical composition belonging to the Fe-Mn-Al-C system, in hot worked condition from X-ray diffraction and eletron microscopy analyses, hardness, and density measurements by Archimedes’ principle. The results indicated that the high added Al promoted a reduction of about 13% in density, in relation to typical structural steels, and the δ ferrite stability up to room temperature. The condition evaluated at room temperature presented a microstructure formed by a matrix with δ and α ferrite, together with k-carbide (AlFe3C) and niobium carbide (NbC) precipitates, the latter two due to the Al and Nb additions, resulting in 59.4 ± 1 HRA hardness and an estimated tensile strength limit close to 800 MPa – within the range of the Advanced High Strength Steels (AHSS).

This work aimed to analyze the damage behavior of cold rolled TRIP780 steel sheet submitted to interrupted uniaxial tensile tests performed along the rolling direction. The formation of voids is investigated as a function of the straining level using digital image analysis of scanning electron micrographs to obtain the measures of void density, void area fraction, void aspect ratio and mean void size. The volume fractions of both ferrite/martensite and retained austenite constituents were obtained from X-ray diffraction measurements. An abruptly decrease of retained austenite was observed at early stages of deformation followed by a slow saturation. The resulting strain-induced martensite is responsible for improving the formability of the TRIP780 as observed by instantaneous strain-hardening exponent. In the lower strain range, growth and coalescence of existing microvoids prevailed at both in-plane directions whereas nucleation of microvoids was also observed along the loading direction. Conversely, nucleation prevailed at the transverse direction in the intermediate strain range whereas growth and coalescence were predominant aligned to the loading direction. At larger strain levels, growth and coalescence of microvoids prevailed at both directions. The microvoids were initially found around inclusions and at the interface of ferrite-martensite phases and lastly also at the ferrite matrix.

RESUMO A desordem temporomandibular pode ser definida como um conjunto de distúrbios que envolvem os músculos mastigatórios, a articulação temporomandibular e estruturas associadas. Atualmente entre 40 a 75% da população apresenta algum sinal de desordem temporomandibular, sendo o mais frequente a dor, principalmente localizada nos músculos da mastigação e na região pré-auricular. O caso clínico apresentado foi diagnosticado como desordem temporomandibular muscular por parafunção, hiperatividade muscular antecedida por deslocamento do músculo temporal esquerdo para realização de duas cirurgias, uma para colocação de clips aneurismático e a outra para remoção de um tumor na região supraorbitária do lado esquerdo. A paciente procurou durante 10 anos ajuda médica e odontológica por sofrer com constantes dores de cabeça, cansaço, dor nas bochechas, usou inúmeras placas, medicamentos, porém o efeito desejado nunca fora alcançado. Frente ao histórico foi aplicado o questionário da Academia Americana de Dor Orofacial e o Critério de Pesquisa e Diagnóstico (RDC), e a conduta clinica adotada foi à aplicação de toxina botulínica tipo A nos músculos masseter e temporal. Foi aplicada uma escala de dor analógica ao longo de 90 dias. Já após 3 dias da aplicação da toxina botulínica tipo A, a paciente relatou melhora significativa chegando a nível 0 de dor após 90 dias. Após 12 semanas do início do tratamento, foram acrescidos exercícios para fortalecimento dos músculos da mastigação, sendo que a paciente continuava sem dor, permitindo desta forma a confecção e instalação de prótese tipo Snap-on. Desta forma, o emprego da toxina botulínica em pacientes com desordem temporomandibular deve ser considerado como uma boa opção terapêutica.

ABSTRACT Temporomandibular disorder (TMD) may be defined as a set of clinical scenarios involving the masticatory muscles, the temporomandibular joint (TMJ) and associated structures. Currently, 40 to 75% of the population has some sign of temporomandibular disorder, mainly pain located in the muscles of mastication in the pre-auricular region. The present clinical case was diagnosed as muscle temporomandibular disorder secondary to parafunction, as well as muscle hyperactivity due to surgical displacement of the left temporal muscle on two occasions, one for placement of aneurysm clips and the other for tumor excision from the supraorbital region on the left side. The patient sought medical and dental attention for 10 years due to constant headaches, tiredness and pain in the cheeks. The patient tried numerous bite-guards and pharmacological therapies to no avail. The American Academy of Orofacial Pain Questionnaire was applied combined with the Criteria for Research and Diagnostics (DRC) and a decision was made to use botulinum toxin type A in the masseter and temporalis muscles. An analog pain scale was applied over 90 days. Three days following the application of botulinum toxin type A, the patient reported a significant improvement with complete resolution of pain (level 0) after 90 days. At 12 weeks from starting treatment, facial muscle physiotherapy was introduced to strengthen the muscles of mastication and the patient remained pain-free, which allowed the preparation and adaptation of a snap-on prosthetic appliance. In conclusion, the use of botulinum toxin in patients with temporomandibular disorder should be considered as a viable therapeutic option.

This article assesses the intention of chemistry teachers to integrate digital media in their classes. The evaluation was performed using a structured questionnaire after participation in two professional development actions. The formative sessions were designed with the aim of training the chemistry teachers for pedagogical integration of digital media in teaching chemistry in high school. The participants were 25 chemistry teachers from different regions of Brazil, who were participating in an international cooperation program for the professional development of teachers in Portugal. Data collection was conducted through questionnaires containing questions about the motivations for innovation in education, attitudes and beliefs in relation to the training actions and face the pedagogical integration of digital media in the chemistry discipline. The data analysis shows a remarkable behavioral intention of adopting the media which is positively correlated with the attitudes and perceptions of control and negatively with subjective norm. These results suggest that interventions focused on technical and pedagogical training centered on subject content are suitable for the professional development of teachers.

In this work, the formability of a hot-dip galvanized interstitial-free (IF) steel sheet was evaluated by means of uniaxial tensile and Forming Limit Curve (FLC) tests. The FLC was defined using the flat-bottomed Marciniak's punch technique, where the strain analysis was made using a digital image correlation software. A plastic localization model was also proposed wherein the governing equations are solved with the help of the Newton's method. The investigated hot-dip galvanized IF steel sheet presented a very good formability level in the deep-drawing range consistent with the measured Lankford values. The predicted limit strains were found to be in good agreement with the experimental data of the hot-dip galvanized IF steel sheet owing to the definition of the localization model geometrical imperfection as a function of the experimental surface roughness evolution and, in particular, to the yield surface flattening near to the plane-strain stress state authorized by the adopted yield criterion.

O objetivo deste estudo foi determinar a prevalência de parasitos intestinais na etnia Maxakali em Minas Gerais, Brasil. Os exames parasitológico das fezes foram realizados através da técnica TF-Test, sendo as amostras fecais coletadas em três dias alternados, em tubos independentes, contendo formol a 10%, unificados para dupla filtragem por centrifugação. Triplicatas de uma alíquota do sedimento foram examinadas em microscópio (10x e 40x) para identificação de ovos, cistos e larvas. A prevalência de parasitos (89,5%) e do poliparasitismo (46%) foi semelhante quanto ao sexo e idade, e variou entre as aldeias. As espécies prevalentes foram: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) e Trichuris trichiura (0,5%). Os Maxakali vivem em condições de vulnerabilidade social, e medidas de infraestrutura e de educação em saúde necessitam ser implementadas pelas instituições governamentais.

A prevalence survey using the TF-Test technique to identify intestinal parasites was conducted in the Maxakali indigenous villages in Minas Gerais State, Brazil. Stool samples were collected on three alternating days, in separate tubes, containing 10% formalin, and unified in a laboratory by double filtering centrifugation. Samples of sediment aliquot were prepared in triplicate and examined by microscope (10x and 40x) for eggs, cysts, and larvae. Prevalence of parasites (89.5%) and polyparasitism (46%) were similar by sex and age, but varied by village. Prevalent species were: Entamoeba histolytica/Entamoeba dispar (48.9%), Giardia duodenalis (32%), Entamoeba coli (40.8%), Endolimax nana (10.3%), hookworms (37.9%), Schistosoma mansoni (23.7%), Hymenolepis nana (18.6%), Strongyloides stercoralis (5.4%), Ascaris lumbricoides (4.9%), and Trichuris trichiura (0.5%). The Maxakali population lives in socially vulnerable conditions, and government agencies need to introduce measures to improve sanitation infrastructure and health education.

El objetivo de este estudio fue determinar la prevalencia de parásitos intestinales en la etnia Maxakali. Los exámenes parasitológicos de las heces se realizaron a través de la técnica TF-Test, las muestras fecales se recogieron en tres días alternados, en tubos independientes, conteniendo formol a un 10%, unificados para un doble filtrado por centrifugación. Triplicados de una alícuota del sedimento se examinaron en microscopio (10x y 40x) para la identificación de huevos, quistes y larvas. La prevalencia de parásitos (89,5%) y del poliparasitismo (46%) fue semejante en cuanto al sexo y edad, y varió entre las aldeas. Las especies prevalentes fueron: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) y Trichuris trichiura (0,5%). Los Maxakali viven en condiciones de vulnerabilidad social, y medidas de infraestructura y de educación en salud necesitan ser implementadas por instituciones gubernamentales.

O objetivo deste estudo foi determinar a prevalência de parasitos intestinais na etnia Maxakali em Minas Gerais, Brasil. Os exames parasitológico das fezes foram realizados através da técnica TF-Test, sendo as amostras fecais coletadas em três dias alternados, em tubos independentes, contendo formol a 10%, unificados para dupla filtragem por centrifugação. Triplicatas de uma alíquota do sedimento foram examinadas em microscópio (10x e 40x) para identificação de ovos, cistos e larvas. A prevalência de parasitos (89,5%) e do poliparasitismo (46%) foi semelhante quanto ao sexo e idade, e variou entre as aldeias. As espécies prevalentes foram: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) e Trichuris trichiura (0,5%). Os Maxakali vivem em condições de vulnerabilidade social, e medidas de infraestrutura e de educação em saúde necessitam ser implementadas pelas instituições governamentais.

A prevalence survey using the TF-Test technique to identify intestinal parasites was conducted in the Maxakali indigenous villages in Minas Gerais State, Brazil. Stool samples were collected on three alternating days, in separate tubes, containing 10% formalin, and unified in a laboratory by double filtering centrifugation. Samples of sediment aliquot were prepared in triplicate and examined by microscope (10x and 40x) for eggs, cysts, and larvae. Prevalence of parasites (89.5%) and polyparasitism (46%) were similar by sex and age, but varied by village. Prevalent species were: Entamoeba histolytica/Entamoeba dispar (48.9%), Giardia duodenalis (32%), Entamoeba coli (40.8%), Endolimax nana (10.3%), hookworms (37.9%), Schistosoma mansoni (23.7%), Hymenolepis nana (18.6%), Strongyloides stercoralis (5.4%), Ascaris lumbricoides (4.9%), and Trichuris trichiura (0.5%). The Maxakali population lives in socially vulnerable conditions, and government agencies need to introduce measures to improve sanitation infrastructure and health education.

El objetivo de este estudio fue determinar la prevalencia de parásitos intestinales en la etnia Maxakali. Los exámenes parasitológicos de las heces se realizaron a través de la técnica TF-Test, las muestras fecales se recogieron en tres días alternados, en tubos independientes, conteniendo formol a un 10%, unificados para un doble filtrado por centrifugación. Triplicados de una alícuota del sedimento se examinaron en microscopio (10x y 40x) para la identificación de huevos, quistes y larvas. La prevalencia de parásitos (89,5%) y del poliparasitismo (46%) fue semejante en cuanto al sexo y edad, y varió entre las aldeas. Las especies prevalentes fueron: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) y Trichuris trichiura (0,5%). Los Maxakali viven en condiciones de vulnerabilidad social, y medidas de infraestructura y de educación en salud necesitan ser implementadas por instituciones gubernamentales.

This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.

A Curva Limite de Conformação (CLC) é uma ferramenta muito útil, tanto na avaliação do comportamento plástico de chapas, quanto no projeto do ferramental para solucionar problemas de manufatura nas etapas de tentativas de erros-e-acertos. Esse trabalho apresenta o modelamento matemático da CLC com base em equações constitutivas em elasto-plasticidade e um critério de plasticidade anisotrópica. Demonstra-se, primeiro, que as deformações-limites no domínio de estiramento biaxial são controladas por um parâmetro material definido pela razão entre os limites de escoamento em deformação plana e tração biaxial simétrica. As previsões teóricas do modelo proposto apresentaram boa concordância com medidas experimentais disponíveis, na literatura, para uma chapa de alumínio A1100, e sugerem, igualmente, que os parâmetros do modelo de plasticidade, adotado para descrever anisotropia inicial de chapas metálicas, sejam identificados com bases em ensaios monotônicos de tração uniaxial e biaxial.

The Forming Limit Curve (FLC) is a very useful tool to assess either the plastic behavior of thin metallic sheets or the tooling design to solve manufacturing problems during the try-out steps. This work presents the mathematical modeling of the FLC based on elasto-plastic constitutive equations and anisotropic plasticity yield criterion. It is firstly demonstrated that the limit strains in the biaxial stretching domain are controlled by a material parameter defined by the ratio between the yield stresses in plane-strain tension and equibiaxial tension. The theoretical predictions of the proposed model showed a good agreement with the experimental data available in the literature for an aluminum A1100 sheet and also indicated that the parameters of plasticity model, adopted to describe the initial plastic anisotropy of metallic sheets, must be identified from monotonic uniaxial and biaxial tensile tests data.

In this opinion paper, we discuss the potential and challenges of using the symbiont Wolbachia to block mosquito transmitted diseases such as dengue, malaria and chikungunya in Latin America.

This study compares the diagnostic accuracy of the TF-Test® (TFT) for human parasitosis with results obtained using the traditional Kato-Katz (KK), Hoffman-Pons-Janer (HPJ), Willis and Baermann-Moraes (BM) techniques. Overall, four stool samples were taken from each individual; three alternate-day TFT stool samples and another sample that was collected in a universal container. Stool samples were taken from 331 inhabitants of the community of Quilombola Santa Cruz. The gold standard (GS) for protozoa detection was defined as the combined results for TFT, HPJ and Willis coproscopic techniques; for helminth detection, GS was defined as the combined results for all five coproscopic techniques (TFT, KK, HPJ, Willis and BM). The positivity rate of each method was compared using the McNemar test. While the TFT exhibited similar positivity rates to the GS for Entamoeba histolytica/dispar (82.4%) and Giardia duodenalis (90%), HPJ and Willis techniques exhibited significantly lower positivity rates for these protozoa. All tests exhibited significantly lower positivity rates compared with GS for the diagnosis of helminths. The KK technique had the highest positivity rate for diagnosing Schistosoma mansoni (74.6%), while the TFT had the highest positivity rates for Ascaris lumbricoides (58.1%) and hookworm (75%); HPJ technique had the highest positivity rate for Strongyloides stercoralis (50%). Although a combination of tests is the most accurate method for the diagnosis of enteral parasites, the TFT reliably estimates the prevalence of protozoa and selected helminths, such as A. lumbricoides and hookworm. Further studies are needed to evaluate the detection accuracy of the TFT in samples with varying numbers of parasites.

Malaria is a mosquito-borne infectious disease caused by Plasmodium parasites transmitted by the infectious bite of Anopheles mosquitoes. Vector control of malaria has predominantly focused on targeting the adult mosquito through insecticides and bed nets. However, current vector control methods are often not sustainable for long periods so alternative methods are needed. A novel biocontrol approach for mosquito-borne diseases has recently been proposed, it uses maternally inherited endosymbiotic Wolbachia bacteria transinfected into mosquitoes in order to interfere with pathogen transmission. Transinfected Wolbachia strains in Aedes aegypti mosquitoes, the primary vector of dengue fever, directly inhibit pathogen replication, including Plasmodium gallinaceum, and also affect mosquito reproduction to allow Wolbachia to spread through mosquito populations. In addition, transient Wolbachia infections in Anopheles gambiae significantly reduce Plasmodium levels. Here we review the prospects of using a Wolbachia-based approach to reduce human malaria transmission through transinfection of Anopheles mosquitoes.

Mosquito-borne diseases such as dengue fever, chikungunya or malaria affect millions of people each year and control solutions are urgently needed. An international research program is currently being developed that relies on the introduction of the bacterial endosymbiont Wolbachia pipientis into Aedes aegypti to control dengue transmission. In order to prepare for open-field testing releases of Wolbachia-infected mosquitoes, an intensive social research and community engagement program was undertaken in Cairns, Northern Australia. The most common concern expressed by the diverse range of community members and stakeholders surveyed was the necessity of assuring the safety of the proposed approach for humans, animals and the environment. To address these concerns a series of safety experiments were undertaken. We report in this paper on the experimental data obtained, discuss the limitations of experimental risk assessment and focus on the necessity of including community concerns in scientific research.

In this work the theoretical solutions based upon the upper-bound theorem recently proposed by Pérez and Luri [Mech. Mater. 40 (2008) 617] for the equal channel angular extrusion process (ECAE) are analyzed by performing a 25 central composite factorial analysis. The uniaxial mechanical properties of commercial pure aluminium are considered by assuming isotropic nonlinear work-hardening combined to von Mises and Drucker isotropic yield criteria to predict the ECAE load and the effective plastic strain. From the proposed 25 factorial analysis, the main parameters affecting the ECAE pressure may be ranked as: (1) Friction factor, (2) die channels intersection angle, (3) outer and (4) inner die corners fillet radii and lastly, (5) plunger velocity. Alternatively, the effective plastic strain is mainly controlled by the die channels intersection angle and, in a less extent, by the outer and inner die corners fillet radii.