The objective of this study was to determine whether coronary vascular resistance remains constant during long diastoles and whether critical closure of arterial microvessels occurs at zero-flow pressure. For this purpose, we directly measured internal diameters and red blood cell velocities in arterial and venous coronary microvessels during long diastoles under maximal vasodilation. The epica...

Eighteen previously unknown martian basins have been detected on Viking photographs. The smallest basins have diameters 50 to 100 km less than the smallest known basins on Mercury or the moon. On the latter two planets and the earth, basin morphology varies with increasing diameter: central peak (CP) basins have both central peaks and fragmentary peak rings; peak ring (PR) basins have only conc...

Background: Stereotactic radiosurgery is an important clinical tool for the treatment of small lesions in the brain, including benign conditions, malignant and localized metastatic tumors. A dosimetry study was performed for Elekta ‘Synergy S ’ as a dedicated Stereotactic radiosurgery unit, capable of generating circular radiation fields with diameters of 1-5 cm at isocentre using the BEAM/EGS4...

Human milk fat globules (HMFGs) are considered to constitute a triglyceride-rich source of fat and energy. However, milk contains lipid particles at different sizes ranging from tens of micrometers to less than 1 microm. In particular, the physical, chemical, and biological properties of submicron sized particles are poorly described. Individual HMFGs were analyzed using laser trapping confocal...

Growth rates of seedlings of eight tropical rain forest tree species were compared under five different canopy openness levels (FU and 50, 200, 800, 3200 m gaps). RGR exhibited a positive relation with canopy openness with species attaining their highest RGR at the 800 m (4 species) or 3200 m (3 species) gaps. Seed mass and RGR were negatively related. The increase in RGR between small and larg...

OBJECTIVE The aim of this study was to determine the influence of aortic annulus (AA) diameter and the ratio of the sinotubular junction (STJ) diameter to the AA diameter on aortic valve hemodynamics and tissue mechanics and to suggest optimal values. METHODS Sixteen cases of aortic roots with AA diameters between 22 and 28 mm and an STJ/AA diameter ratio between 0.8 and 1.4 were numerically ...

Mapping axon diameter is of interest for the potential diagnosis and monitoring of various neuronal pathologies. Advanced diffusion-weighted MRI methods have been developed to measure mean axon diameters non-invasively, but suffer major drawbacks that prevent their direct translation into clinical practice, such as complex non-linear data fitting and, more importantly, long scanning times that ...

In the coastal temperate rainforests of southeast Alaska, much progress has been made in describing landscape-level natural disturbances and formulating management systems that emulate those disturbances. Little is known, however, concerning canopy gaps, the dominant form of natural disturbance in the region. During June–August, 1991–1993, we characterized canopy gap patterns and dynamics at th...

We present extensive stimulated Brillouin scattering (SBS) results from experiments and modeling for four different photonic crystal fibers (PCFs) with core diameters ranging from 8 to 1.7 m. These results reveal several SBS characteristic features of small-core PCFs, high thresholds, and acoustic peaks, which are due to their antiguiding nature and highly multimode acoustic character. The natu...

In small vessels blood is usually treated as a Newtonian fluid down to diameters of ~200 μm. We investigate the flow of red blood cell (RBC) suspensions driven through small tubes (diameters 10-150 μm) in the range marking the transition from arterioles and venules to the largest capillary vessels. The results of the simulations combined with previous simulations of uniform shear flow and exper...