The aim of this research is to determine the possible solar energy storage in the norbornadiene (1) / quadricyclane (2) system, through involving steric effects on various position of carbon C1, C2 or C7 for 1 and 2; calculating the corresponding energies at B3LYP/6-311G** level of theory. The extent of the solar energy storage is the least for 11-i-Pr (-21.018), 12-t-Bu (-22.525) and 17-i-Pr (...

Availability, ease of use, relative low cost, and minimal radiation exposure have made dual-energy x-ray absorptiometry the most widely used technique worldwide to obtain bone measurements for both research and clinical purposes in pediatric populations. However, errors related to growth and maturity significantly diminish the accuracy of dual-energy x-ray absorptiometry bone measurements. Seve...

Osteoporosis is a multifactorial disease characterized by a decrease in bone mass and deterioration of bone architecture. Genetic factors are determinants of peak bone mass and may influence age-related decreases of bone mass. WHO has established an operational criterion based on bone density measuring, the T-score. 122 cases were studied, 51 diagnosed with primary osteoporosis. Mean age was 57...

This article reviews the dual-energy x-ray absorptiometry (DXA) technique, its interpretation, and clinical applications with emphasis on the considerations unique to pediatrics. Specifically, the use of DXA in children requires the radiologist to be a “clinical pathologist,” monitoring the technical aspects of the DXA acquisition, a “statistician” knowledgeable in the concepts of Z-scores and ...

The applications of Dual-energy X-ray Absorptiometry (DXA) to vertebrate research and veterinary practice are many. DXA has been used successfully to rapidly and non-invasively quantify bone density and body composition in a variety of animals. The use of DXA has been limited, primarily, to basic and applied research, but DXA technology has great promise for clinical practice involving animals....