Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that describe human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Stylized phantoms are flexible in that changes to organ position and shape are possible given avoidance of region overlap, while voxel phantoms are typically fixed to a given patient anatomy, yet can be proportionally scaled to match individuals of larger or smaller stature, but of equivalent organ anatomy. Voxel phantoms provide much better anatomical realism as compared to stylized phantoms which are intrinsically limited by mathematical surface equations. To address the drawbacks of these phantoms, hybrid phantoms based on non-uniform rational B-spline (NURBS) surfaces have been introduced wherein anthropomorphic flexibility and anatomic realism are both preserved. Researchers at the University of Florida have introduced a series of hybrid phantoms representing the ICRP Publication 89 reference newborn, 15 year, and adult male and female. In this study, six additional phantoms are added to the UF family of hybrid phantomsthose of the reference 1 year, 5 year and 10 year child. Head and torso CT images of patients whose ages were close to the targeted ages were obtained under approved protocols. Major organs and tissues were segmented from these images using an image processing software, 3D-DOCTOR TM . NURBS and

Experimental and theoretical studies of singlet oxygen excitation in travelling microwave (TMW) discharges are presented. Singlet oxygen O2(a1Δg) concentrations and atomic oxygen mole fraction have been measured for different pressures, input powers and distances from the MW resonator. It was shown that a steady-state TMW discharge with a coaxial cavity resonator could provide a maximal O2(a1Δg) yield of 22% for 2 Torr of pure oxygen and 27–30% for He : O2 = 1 : 1 mixture. The two-dimensional (r, z) model developed for calculations of plasma-chemical kinetics, heat and mass transfer was used for simulation of processes in the TMW discharge under study. Effects of gas pressure, gas flow rate and input power are studied and compared with experimental measurements of O2(a1Δg) concentrations and atomic oxygen mole fractions.

The spectrum analysis method of determining the metal content from 10−10 to 10−11 gram in aerosol samples deposited on a cathode is described. By this method, the authors have measured the concentrations of 11 metals in air over locations within the USSR and in maritime regions. The concentrations of these elements in air over the ocean in the northern and southern hemispheres also were measured. Results are compared and their relation to meteorological parameters is discussed.

Purpose:to study the frequency and structure of undifferentiated connective tissue dysplasia (UCTD) in school-age children with myopia, their relationship to choroidal thickness and course of myopia.Patients and methods. The object of study was 120 children (240 eyes) aged 11–13 years with school axial myopia (axial length (AL) from 24.5 to 26.0 mm). Special ophthalmological examination included optical coherent tomography of macular zone (“RTVue 100” Optovue, USA) and “Cross Line” scan for measuring choroidal thickness in foveal area and 1000 μm from it in nasal and temporal regions.Results.According to studies, the phenotypic signs of UCTD were diagnosed in 56 children (46.7%) with school myopia, the largest group included phenotypic signs of locomotor syndrome; 14 children (25%) had a weak degree of UCTD, 34 children (60.7%) — moderate degree and 8 children (14.3%) — pronounced degree. Comparative characteristic of changes in choroidal thickness detected a high degree of interrelation between the severity of clinical manifestations of UCTD and the level of decrease in blood-flow in the choroid. In children of the main group with signs of UCTD, the annual growth of AL exceeded the same parameters in children of the control group by more than 2.5 times (p < 0.05); due of accumulation of phenotypic signs of UCTD, a more noticeable tendency to decrease of choroidal thickness and the increase of AL was observed (p < 0.05). The statistical analysis confirmed the presence of significant negative correlation between the decrease in average thickness index in segment of the macular map and the degree of increase of AL (p < 0.05).Conclusions. According to results of diagnostic screening, in 46.7% children with school myopia, we detected phenotypic signs of UCTD. The method of optical coherence tomography showed that with increasing severity of UCTD, indexes of choroidal thickness in the macular zone are significant decreased. In the catamnesis (duration 1 year), it was found that in children with myopia with moderate and pronounced degrees of UCTD, increase of AL is associated with degree of thinning choroidal thickness, which indicates violations of biomechanical status of sclera.

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