ASEPTIC NECROSIS OF THE FEMORAL HEAD: WHAT DO WE KNOW ABOUT TREATMENT OPTIONS?

Aseptic necrosis of the femoral head is one of the most important problems in traumatology, a complex disease in which there is a gradual deformation of the femoral head in the places where the greatest load is applied to it. The disease is the cause of disability in 7% of all orthopedic patients with lower limb dysfunction. There are various surgical and conservative approaches to the treatment of this pathology. This article provides an overview of the available data on the use of these methods for the correction of osteonecrosis of the hip joint.

The Band-Gap Studies of Short-Period CdO/MgO Superlattices.

Trends in the behavior of band gaps in short-period superlattices (SLs) composed of CdO and MgO layers were analyzed experimentally and theoretically for several thicknesses of CdO sublayers. The optical properties of the SLs were investigated by means of transmittance measurements at room temperature in the wavelength range 200-700 nm. The direct band gap of {CdO/MgO} SLs were tuned from 2.6 to 6 eV by varying the thickness of CdO from 1 to 12 monolayers while maintaining the same MgO layer thickness of 4 monolayers. Obtained values of direct and indirect band gaps are higher than those theoretically calculated by an ab initio method, but follow the same trend. X-ray measurements confirmed the presence of a rock salt structure in the SLs. Two oriented structures (111 and 100) grown on c- and r-oriented sapphire substrates were obtained. The measured lattice parameters increase with CdO layer thickness, and the experimental data are in agreement with the calculated results. This new kind of SL structure may be suitable for use in visible, UV and deep UV optoelectronics, especially because the energy gap can be precisely controlled over a wide range by modulating the sublayer thickness in the superlattices.

Postural hypotension and mental function in the elderly.

The effect of 3 hours of ambulatory activity on the mental function of 12 elderly persons with postural hypotension was examined. There was little difference between the mean combined mental status and set test scores when the subjects were supine (42.3) and when they were erect after 3 hours of ambulatory activity (42.2). A control group of persons of similar age and health who did not have hypotension also exhibited little difference in mean scores (49.9 v. 51.5 respectively). The mean scores of the two groups of subjects did not differ significantly. After 6 months the mean scores of the two groups were 40.9 and 44.7 respectively. It appears that elderly individuals with postural hypotension do not exhibit any appreciable deterioration in mental function with ambulation or after a 6-month period.