Indentation of the cornea: A Bi-layer contact problem.

Histological observations of the cornea have identified the presence of multiple layers with differing thickness and function. The composition of the cornea consists primarily of collagen fibrils held together with proteoglycans but with an aqueous interstitial component being dominant. Indentation provides a means to quantify the spatial variation of the mechanical properties of the cornea, however the role of the different layers on the indentation response has barely been addressed. In addition, the response of the fluid content and its displacement during indentation has not been adequately considered. In this study indentation of the cornea with a relatively large spherical tipped indenter (R = 500 µm) is considered. It was observed that the initial phase of loading did not fit a classic Hertz elastic response but showed an initial steeper slope that gradually declines with increasing force and displacement. A relatively simple approach is developed that initially considers the cornea as a poro-elastic bi-layer contact problem, that is the presence of an outer thin stiffer Bowman's layer overlaying the thicker less stiff stroma.

Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter.

The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions.

Minimal-change nephrotic syndrome associated with malignant mesothelioma.

A 68-year-old man presented with nephrotic syndrome. Renal biopsy revealed minimal-change glomerular disease. The proteinuria did not respond to treatment with prednisone and cyclophosphamide. On further workup, the patient was found to have a malignant mesothelioma of the pleura. The proteinuria then improved during treatment with doxorubicin hydrochloride and dacarbazine, without noticeable improvement in the tumor. This case suggests an association between mesothelioma and minimal-change glomerular disease with nephrotic syndrome, previously unreported to our knowledge. Our review revealed only ten previous cases of minimal-change glomerular disease associated with carcinoma.

Relationships of oral stereognostic ability to age and sex of children.

A battery of items testing oral stereognostic ability was individually presented to 168 children, 12 boys and 12 girls at each of seven age levels from 4-5 to 11-4. Age was significantly related to oral stereognostic scores; older subjects scored significantly higher than younger subjects. Sex was also significant; girls scored higher than boys. The interaction of age and sex was not significant.

Functional method for assessing oral perceptual skills in children.

An alternative method for assessing oral perceptual skills was developed to address some of the practical limitations of the standard form test. The alternate forms and standard NIH Oral Stereognostic Forms were administered to 182 children. Scores resulting from presentation of standard NIH forms and alternate edibles correlated .76. Suggestions for using the alternate forms for routine oral stereognostic testing are presented.