Computational simulation of ultrasonic fields

When an electro-acoustical transducer is electrically supplied, it yields an acoustic field in the propagation medium. The acoustic field knowledge allows us to obtain significant help to transducers design and propagation medium interaction studies. In this paper, it is shown a proposal of classroom work involving the studied contents of physics, mathematic and computing in the introductory lessons of degree course of exact science. It is proposed the discussion about wave interference phenomena, the determination of acoustic field using cylindrical coordinates and the software of the mathematical method applying basic instructions of a computational language. The simulations of some acoustic fields are shown in bi and tri-dimensional graphics and the results are discussed.Quando um transdutor eletro-acústico é excitado eletricamente, ele produz no meio de propagação onde está inserido um campo acústico. Através do conhecimento dos campos acústicos pode-se colher importantes subsídios para projetos de transdutores e estudos da interação com os meios de propagação. Neste trabalho é apresentada uma proposta de atividade interdisciplinar envolvendo conteúdos de Física, Matemática e Computação ministrados nas disciplinas introdutórias dos cursos superiores de ciências exatas e tecnológicas. O trabalho propõe a discussão dos fenômenos de interferência ondulatória, o cálculo do campo acústico usando coordenadas cilíndricas e a programação do método matemático através de instruções básicas de uma linguagem de programação. As simulações de alguns campos acústicos são apresentadas na forma de gráficos bi e tridimensionais e os resultados são discutidos.22323

Simulação computacional de campos ultra-sônicos

Quando um transdutor eletro-acústico é excitado eletricamente, ele produz no meio de propagação onde está inserido um campo acústico. Através do conhecimento dos campos acústicos pode-se colher importantes subsídios para projetos de transdutores e estudos da interação com os meios de propagação. Neste trabalho é apresentada uma proposta de atividade interdisciplinar envolvendo conteúdos de Física, Matemática e Computação ministrados nas disciplinas introdutórias dos cursos superiores de ciências exatas e tecnológicas. O trabalho propõe a discussão dos fenômenos de interferência ondulatória, o cálculo do campo acústico usando coordenadas cilíndricas e a programação do método matemático através de instruções básicas de uma linguagem de programação. As simulações de alguns campos acústicos são apresentadas na forma de gráficos bi e tridimensionais e os resultados são discutidos

Head posture and dental wear evaluation of bruxist children with primary teeth

2 SUMMARY The aim of the present study was to compare the head position and the dental wear between bruxist and non-bruxist children with primary dentition. Methods: All the subjects had complete primary dentition, dental and skeletal class I occlusion and were classified as bruxist or non-bruxist according to their anxiety level, bruxism described by their parents and signs of temporomandibular disorders. The dental wear was drawn in dental casts and processed in digital format. Physiotherapeutic evaluation and a cephalometric radiograph with natural head position were also performed for each child to evaluate the cranio-cervical position for the bruxist (n = 33) and the control group (n = 20). The variables were compared between the two groups, using the Student t-test and Mann-Whitney U-test. Results: A more anterior and downward head tilt was found in the bruxist group, with statistically significant differences compared with the controls. More significant dental wear was observed for the bruxist children. Conclusions: Bruxism seems to be related to altered natural head posture and more intense dental wear. Further studies are necessary to explore bruxism mechanisms

A New Sugarcane Cystatin Strongly Binds to Dental Enamel and Reduces Erosion.

Cystatin B was recently identified as an acid-resistant protein in acquired enamel pellicle; it could therefore be included in oral products to protect against caries and erosion. However, human recombinant cystatin is very expensive, and alternatives to its use are necessary. Phytocystatins are reversible inhibitors of cysteine peptidases that are found naturally in plants. In plants, they have several biological and physiological functions, such as the regulation of endogenous processes, defense against pathogens, and response to abiotic stress. Previous studies performed by our research group have reported high inhibitory activity and potential agricultural and medical applications of several sugarcane cystatins, including CaneCPI-1, CaneCPI-2, CaneCPI-3, and CaneCPI-4. In the present study, we report the characterization of a novel sugarcane cystatin, named CaneCPI-5. This cystatin was efficiently expressed in Escherichia coli, and inhibitory assays demonstrated that it was a potent inhibitor of human cathepsins B, K, and L ( Ki = 6.87, 0.49, and 0.34 nM, respectively). The ability of CaneCPI-5 to bind to dental enamel was evaluated using atomic force microscopy. Its capacity to protect against initial enamel erosion was also tested in vitro via changes in surface hardness. CaneCPI-5 showed a very large force of interaction with enamel (e.g., compared with mucin and casein) and significantly reduced initial enamel erosion. These results suggest that the inclusion of CaneCPIs in dental products might confer protection against enamel erosion.This research was supported by the São Paulo Research Foundation (FAPESP) (CEPID-CBME #98/14138-2) and by the Royal Society (Newton Advanced Fellowship #NA140459). A.C.S. is a recipient of a scholarship from the National Council for Scientific and Technological Development (CNPq). M.C.M. received a grant from the Coordination for the Improvement of Higher Education Personnel (CAPES). V.T.P. received a grant from the FAPESP. F.H.-S. and M.A.R.B. were recipients of a productivity scholarship from the CNPq