Microsaccade rate activity during the preparation of pro- and antisaccades.

Microsaccades belong to the category of fixational micromovements and may be crucial for image stability on the retina. Eye movement paradigms typically require fixational control, but this does not eliminate all oculomotor activity. The antisaccade task requires a planned eye movement in the direction opposite of an onset, allowing separation of planning and execution.

Temporal Limitations of the Standard Leaky Integrate and Fire Model.

Itti and Koch's Saliency Model has been used extensively to simulate fixation selection in a variety of tasks from visual search to simple reaction times. Although the Saliency Model has been tested for its spatial prediction of fixations in visual salience, it has not been well tested for their temporal accuracy. Visual tasks, like search, invariably result in a positively skewed distribution of saccadic reaction times over large numbers of samples, yet we show that the leaky integrate and fire (LIF) neuronal model included in the classic implementation of the model tends to produce a distribution shifted to shorter fixations (in comparison with human data).

Salience Models: A Computational Cognitive Neuroscience Review.

The seminal model by Laurent Itti and Cristoph Koch demonstrated that we can compute the entire flow of visual processing from input to resulting fixations. Despite many replications and follow-ups, few have matched the impact of the original model-so what made this model so groundbreaking? We have selected five key contributions that distinguish the original salience model by Itti and Koch; namely, its contribution to our theoretical, neural, and computational understanding of visual processing, as well as the spatial and temporal predictions for fixation distributions. During the last 20 years, advances in the field have brought up various techniques and approaches to salience modelling, many of which tried to improve or add to the initial Itti and Koch model.

Biochemical and physico-chemical aspects of biomaterials calcification.

Intrinsic tissue calcification mainly results from increased penetration of plasma proteins into the leaflets of bioprosthetic cardiac valves. The loss of activity of natural calcification inhibitors changes tissue properties and promotes pathological processes. N-vinylpyrrolidone, 3-amino-1,1-hydroxypropylendiphosphonic acid, O,O-diethylvinylphosphonates and antiaggregant (acryloilsalicylic acid) were used to decrease porosity and prevent calcification.

New cardiac bioprostheses: theory, experiments, and 10 years of clinical use.

The biological valve "BAKS" has the following specific features: (1) it is practically devoid of immunogenicity due to fermentative-chemical treatment; (2) it is completely treated with glutaraldehyde through gradual soaking in solutions of increasing concentration; (3) the biological part is fashioned taking into account the biomechanics of the aortic root; (4) the polypropylene stent is functional due to the use of the principles of bionics in valve construction; and (5) practically no thromboemboli occur, because of the special morphologic organization of the cuff and the distant location of the bioprosthesis leaflets from the stent edge. In the Department of Heart Surgery of the National Research Center of Surgery, "BAKS" valves have been used in 237 patients undergoing isolated mitral valve replacement for rheumatic heart disease. Of these 35% were younger than 35 years, 93.