Time-resolved quantitative multiphase interferometric imaging of a highly focused ultrasound pulse

Interferometric imaging is a well established method to image phase objects by mixing the image wavefront with a reference one on a CCD camera. It has also been applied to fast transient phenomena, mostly through the analysis of single interferograms. It is shown that for repetitive phenomena multiphase acquisition brings significant advantages. A 1 MHz focused sound field emitted by a hemispherical piezotransducer in water is imaged as an example. Quantitative image analysis provides high resolution sound field profiles. Pressure at focus determined by this method agrees with measurements from a fiber-optic probe hydrophone. This confirms that multiphase interferometric imaging can indeed provide quantitative measurements

Testing of aspheric surfaces with computer generated holograms

Aspherical surfaces are becoming more important and can even be mass producted. There is a need for flexible test methods of high accuracy. The paper describes the combination of a computer generated holograms with a partially compensating lens as a powerful tool. An example for testing a steep aspheric surface will be given

Phase retrieval from carrier frequency interferograms: reduction of the impact of space-variant disturbances

Phase “extraction" by using temporal phase shifting is sensitive to vibrations and drifts, producing systematic phase errors periodic with twice the fringe frequency. This error source may be avoided by evaluating only single carrier frequency interferograms, which makes the procedure immune against vibrations and drifts provided that the integration time is short enough to freeze the fringe pattern. However, the phases extracted from single interferograms in this way often show local irregularities depending on the mean phase of the interference pattern. Such local phase irregularities are caused by local disturbances in the light path like specks and dust particles on the optical components of the interferometer. Moreover, since digitized data are gathered, there is a nonlinear processing step involved which is also responsible for the generation of such irregularities. Here, it is proposed to use a set of suitably combined phase-ramped interferograms to reduce phase dependent irregularities. The proposed averaging technique also reduces edge ringing effects known from Fourier evaluation procedures. Since the imaging optics also contributes to the phase to be measured when tilted wavefronts are used, calibration is mandatory. The calibrated state is only valid if strict rules considering fringe number per diameter as well as the position of the wedge in the interferometer are maintained in the measuring process

Silicose pulmonar e doenças autoimunes: série de casos e revisão de literatura / Pulmonary silicosis and autoimmune diseases: case series and literature review

A exposição ocupacional ao dióxido de sílica é responsável pelo desenvolvimento de silicose pulmonar, doença caracterizada por inflamação crônica e fibrose pulmonar. Tal condição impacta em qualidade de vida e morbimortalidade e é considerada pela Organização Mundial de Saúde (OMS) um agravo à saúde mundial. O estímulo inflamatório causado pela exposição à sílica pode funcionar como gatilho imunológico para o desenvolvimento de doenças autoimunes como Lupus Eritematoso Sistêmico (LES), Artrite Reumatóide (AR), Esclerose Sistêmica (ES), Síndrome de Sjögren (SS) e vasculite relacionada à anticorpos anti-citoplasma de neutrófilo (ANCA). Em associação, silicose pulmonar e doenças autoimunes interferem fortemente de maneira negativa na sobrevida. O presente estudo descreve uma série de casos relacionando silicose pulmonar com doenças autoimunes e realiza uma abrangente revisão de literatura sobre o tema. Objetivamos enfatizar a importância da prevenção da exposição ocupacional e da abordagem do histórico laboral no atendimento médico, buscando identificar e intervir precocemente nas condições patológicas associadas