Comparison of mechanical properties for equiaxed fine-grained and dendritic high-palladium alloys

Two Pd-Cu-Ga alloys and a Pd-Ga alloy were selected for study. Bars of each alloy were tested in tension for the as-cast and simulated porcelain-firing conditions, and values of mechanical properties were measured. Fracture surfaces and microstructures of axially sectioned fracture specimens were observed with the SEM. The two Pd-Cu-Ga alloys exhibited similar mechanical properties. The Pd-Ga alloy had lower strength and higher percentage elongation. Heat treatment simulating porcelain firing cycles decreased the strength of both Pd-Cu-Ga alloys and increased their ductility. However, this heat treatment did not significantly affect the mechanical properties of the Pd-Ga alloy. All three high-palladium alloys had the same modulus of elasticity. The amount of overall porosity was relatively minimal (< 1%) and not significantly different among the three alloys. However, porosity was a significant factor for UTS of one Pd-Cu-Ga alloy and the Pd-Ga alloy.

Male-pattern alopecia and masculinity

Cutaneous processes which are thought to be influenced by androgenic stimulation include the development of male-pattern alopecia, terminal hair distribution, sebum excretion rate, maximal sweat secretion rate and skin thickness. We measured these indices in forty-eight normal men, together with muscle, fat and bone thickness and plasma testosterone. There was a significant correlation between hair density on the forearm, leg and chest, but no other significant correlations were found. We conclude that bald men are no more 'masculine' than those with good scalp hair growth, if masculinity is defined in terms of end-organ response to androgenic stimulation.

Capacitance-torsion balance for measuring small stresses and strains

A versatile and inexpensive capacitance-torsion balance has been developed to measure, simultaneously and continuously, small forces and displacements in remotely located samples. It can also be used as a sensitive dilatometer or as a microbalance. The present instrument provides an output voltage change of 1 V for a load change of 3 g and a displacement of 5x10(-5) m. These load and displacement ranges can be independently chosen by adjusting the geometrical configuration of the balance, whereas the sensitivity is independent of the range.

Myocardial infarction, androgen and the skin

Various indices of masculinity were compared in 48 men who had recovered from myocardial infarction and in their age-matched controls. We found little evidence to support the idea that myocardial infarction is related to increased androgenic stimulation. The patients with myocardial infarction had no increase in plasma testosterone, muscle thickness, sebum excretion rate, maximal sweat secretion rate, male pattern alopecia or density of terminal body hair, but as a group they had a slight increase in skin and bone thickness compared with the controls.

Effect of oral contraceptives on sebum excretion rate

Oral contraceptives containing a high dose of oestrogen reduce the sebum excretion rate (SER) and improve acne vulgaris, but more progestogenic preparations may exacerbate acne. The effect on the SER of several oral contraceptives with varying progestogenic potencies was studied in 81 women. The predominantly progestogenic pills (Eugynon 30, Gynovlar) produced no significant change in SER, whereas the rate in women taking a more oestrogenic pill (Minovlar) was significantly reduced compared with the rate in controls. Progestogens therefore do not exacerbate acne by inducing seborrhoea, but in the doses we studied they nullified the inhibitory effect of oestrogens on the sebaceous glands. Acne-prone women who require an oral contraceptive should be given a predominantly oestrogenic preparation.

Skin surface lipid composition in rosacea

Skin surface lipid composition was measured in thirty-one patients with rosacea and their age-matched controls. Patients with rosacea had normal lipid composition, and there was no correlation between the lipid composition and the severity of the disease. Tetracycline therapy produced no measurable change in lipid composition.

The sebum excretion rate in rosacea

The sebum excretion rate (SER) was measured in fifty-five patients with rosacea and 126 control subjects. The mean SER in the patients with rosacea was not increased, nor was there any correlation between SER and severity of rosacea. Our data suggest that seborrhoea plays no part in the pathogenesis of rosacea.