Use of a Rotating Square Spatial-Frequency Filter to Map the Optical Path Length Variation in Microscopic Biological Samples.

Gradient images can be obtained using a rotating square mask to filter the angular spectra of the wavefront generated by a complex transmittance object. This method can be applied to measure the three-dimensional structure of microscopic biological samples through the relationship of the phase with the optical path length. This work describes the implementation of a system using an inverted optical microscope and shows the experimental results of phase maps generated by boar sperm cells.

Outcomes of Nonagenarians With ST Elevation Myocardial Infarction.

Although older adults are the fastest-growing age group among cardiovascular patients, nonagenarians with ST-segment elevation myocardial infarction (STEMI) are under-represented in clinical trials. The aims of this study are to analyze the clinical presentation and outcomes of nonagenarian patients presenting with STEMI and to compare in-hospital and 1-year clinical outcomes between those treated with optimal medical treatment alone and those receiving primary percutaneous coronary intervention (pPCI). We included all consecutive nonagenarians presenting with STEMI admitted in 2 academic centers between 2006 and 2018.

A method to simulate the optical image from far-field scattering numerical data and its application to the total internal reflection microscopy of metallic nanowires.

Computational electrodynamics modelling plays an important role in understanding and designing new photonic devices. The results offered by these simulations are usually close-range field distributions or angular power emission plots. We describe a procedure to compute the optical microscopy image from simulated far-field scattering data using three-dimensional discrete Fourier transforms that can be used when the simulation software package do not include proper far-field to optical imaging projection routines.

Tomographic imaging of transparent biological samples using the pyramid phase microscope.

We show how a pyramid phase microscope can be used to obtain tomographic information of the spatial variation of refractive index in biological samples using the Radon transform. A method that uses the information provided by the phase microscope for axial and lateral repositioning of the sample when it rotates is also described. Its application to the reconstruction of mouse embryos in the blastocyst stage is demonstrated.

Plenoptic projection fluorescence tomography.

A new method to obtain the three-dimensional localization of fluorochrome distributions in micrometric samples is presented. It uses a microlens array coupled to the image port of a standard microscope to obtain tomographic data by a filtered back-projection algorithm. Scanning of the microlens array is proposed to obtain a dense data set for reconstruction.

Phase estimation from digital holograms without unwrapping.

Digital holography is a convenient method for determining the phase induced by transparent objects. When the phase change is higher than 2π, an unwrapping algorithm is needed to provide a useful phase map. In the presence of noise, this process is not trivial and not fully resolved.

Quantitative phase microscopy of transparent samples using a liquid crystal display.

We propose a new quantitative phase microscope based on spatial filtering of the beam carrying the sample-induced wavefront. A prototype built using a transmissive liquid crystal display for the experimental demonstration of the principle and preliminary results obtained with artificial and biological samples are presented.

Mitral stenosis after IMR ETlogix ring annuloplasty for ischemic regurgitation.

Objectives: Ring annuloplasty combined with coronary artery bypass grafting is the standard approach for treatment of patients with ischemic mitral regurgitation. We evaluated mitral valve hemodynamic performance and recurrence of mitral regurgitation after ring annuloplasty.

Patients And Methods: 40 consecutive patients (mean age, 70±8 years) with chronic ischemic mitral regurgitation grade ≥2+ received annuloplasty with an IMR ETlogix ring.

Light spin forces in optical traps: comment on "Trapping metallic Rayleigh particles with radial polarization".

An incomplete modeling of the scattering forces on a Rayleigh particle without taking into account the light spin forces in "Trapping metallic Rayleigh particles with radial polarization" by Q. Zhan, leads to erroneous statements on the advantages of using radial polarization to trap metallic particles.

Pyramid phase microscopy.

A phase microscopy method based on the use of a refractive glass pyramid to determine the wavefront generated by a transparent microscopic sample is presented. The method uses the incoherent illumination of the sample to statically extend the sensor dynamic range. A description, experimental demonstration, and preliminary results are presented.

Fluorescence tomographic microscopy by wavefront detection.

A new method, to our knowledge, for real-time direct access to depth information in scanning fluorescence microscopy is reported. It is based on axially exciting the sample and detecting the phase and intensity of the emitted light. Results obtained using an axicon lens to generate a Bessel beam for excitation and a microlens array as phase detector are presented.

Scanning illumination-acquisition system for noncontact optical tomography.

A new method for the detection of light traversing a diffuser/nondiffuser interface and its simultaneous determination for optical tomography is proposed, and the preliminary results are shown. The method is based on the use of a point detector and two uncoupled scanning systems-one for illumination and the other for registration-together with active modification of the optics guided by the surface topography to generate virtual detectors on the interface.

[Agreement between centers on the interpretation of exercise echocardiography].

Introduction And Objectives: A low-to-moderate level of agreement on the interpretation of dobutamine echocardiography has been reported, but there are no similar findings on exercise echocardiography. The objectives of this study were to assess the level of agreement between centers on the use of exercise echocardiography and to evaluate the accuracy of the technique when used in a blinded manner.

Patients And Method: Six institutions with experience in exercise echocardiography each sent 25 study results to the other centers.

Directional light scanning laser ophthalmoscope.

The cone photoreceptor mosaic of the living human eye has in a limited number of cases been imaged without the use of wavefront-correction techniques. To accomplish this, the directionality of the photoreceptors, as manifested by their waveguiding properties, may be used to advantage. In the present paper we provide a model of our recently proposed directional light scanning laser ophthalmoscope [Opt.

Guided light and diffraction model of human-eye photoreceptors.

The photoreceptors of the living human eye are known to exhibit waveguide-characteristic features. This is evidenced by the Stiles-Crawford effect observed for light incident near the pupil rim, and by the directional component of light reflected off the retina in the related optical Stiles-Crawford effect. We describe a model for the coupling of light to/from photoreceptors on the basis of waveguide theory that includes diffraction between the eye pupil and the photoreceptor apertures, and we show that valuable insight can be gained from a Gaussian approximation to the mode field.

Directional imaging of the retinal cone mosaic.

We describe a near-IR scanning laser ophthalmoscope that allows the retinal cone mosaic to be imaged in the human eye in vivo without the use of wave-front correction techniques. The method takes advantage of the highly directional quality of cone photoreceptors that permits efficient coupling of light to individual cones and subsequent detection of most directional components of the backscattered light produced by the light-guiding effect of the cones. We discuss details of the system and describe cone-mosaic images obtained under different conditions.

Extended source pyramid wave-front sensor for the human eye.

We describe a new wave-front sensor based on the previously proposed pyramid sensor. This new sensor uses an extended source instead of a point-like source avoiding in this manner the oscillation of the pyramid. After an introductory background the sensor functioning is described.

[The use of the EKL-COMPACT lithotriptor in the endoscopic treatment of ureteral lithiasis].

Objective: To report on our experience with the EKL-Compact (Olympus) lithotriptor in the treatment of ureteral calculi.

Methods/results: From December, 1994 to December, 1995, we performed 192 ureteroscopy procedures for endoscopic treatment of ureteral calculi. Stone removal was achieved without necessitating fragmentation in 131 cases.