Comparison of the accuracy of digital stereophotogrammetry and projection moiré profilometry for three-dimensional imaging of the face.

The aim of this study was to compare the three-dimensional (3D) imaging accuracy between a digital stereophotogrammetry device and a projection moiré profilometry setup using anatomical models in conjunction with surface matching software. Twenty-two 3D surface models of the middle third of the face derived from computed tomography (CT) scans were used to fabricate photopolymer models by rapid prototyping. These were digitized using digital stereophotogrammetry and projection moiré profilometry. The 3D surface models acquired were compared for shape differences with the original CT models using surface matching software. Global registration between each pair of corresponding models was carried out using an iterative closest point algorithm. The mean surface deviations following registration were used to calculate Bland-Altman limits of agreement between the two methods. The distributions of measured surface differences were used to calculate L-moments. Paired t-tests were carried out for hypothesis testing. Correlation between difference and mean was -0.3, and 95% limits of agreement were -0.084mm and 0.064mm. No statistically significant differences in mean measurement error (L1 moments) were observed (P=0.1882). The experimental moiré profilometry setup employed produced 3D models of facial anatomy of comparable accuracy to a widely used commercialized digital stereophotogrammetry device.

Assessing urban habitat quality using spectral characteristics of Tilia leaves.

Monitoring environmental quality in urban areas is an important issue offering possibilities to control and improve urban habitat quality as well as to avoid adverse effects on human health. A tree leaf reflectance-based bio-monitoring method was used to assess the urban habitat quality of two contrasting habitat classes in the city of Gent (Belgium). As test trees, two Tilia species were selected. Custom made Matlab code is applied to process the measurements of leaf reflectance. This enables the discrimination between polluted and less polluted habitats. The results elicit, that leaf reflectance in the PAR range, as well as the NDAI (Normalised Difference Asymmetry index) are species dependent while Dorsiventral Leaf Reflectance Correlation (DLRC) seems to be independent of species. Therefore the assessment of urban habitat quality is perfectly feasible using leaf reflectance, when taking account of the species specificity of tree leaf physiological and structural responses to habitat quality.

Atmospheric pressure fluctuations in the far infrasound range and emergency transport events coded as circulatory system diseases.

This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72-11.07 Pa, n = 87) compared to the low DHA (0.7-3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21-1.64, n = 229) compared to the high Rdn (1.65-7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.

Morphology and function of Bast's valve: additional insight in its functioning using 3D-reconstruction.

The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast's valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricular side is that of a flattened funnel. In the direction of the endolymphatic duct and sac this funnel runs into a very narrow duct. The valve itself has a rigid 'arch-like' configuration. The opposing thin, one cell-layer thick, utricular membrane is highly compliant. We propose that opening and closure of the valve occurs through movement of the flexible base/utricular membrane away from and toward the relatively rigid valve lip.