Rabbit eye was irradiated with an ultraviolet laser beam to study its effects on the corneal epithelium and endothelium. The right eye was irradiated with an Excimer laser beam (XeCl gas) of 308nm wave length with an energy intensity of 4.0J/cm2, with six rabbits being used. Their fellow eyes were used as controls. In histological examination, the eye-ball was enucleated immediatly after irradiation. The cornea was fixed in 10% formalin, embedded in paraffin and then sectioned. The sections were stained with hematoxylin-eosin and toluidine blue and then examined by light microscopy. In scanning electron microscopic examination, the eye-ball was bisected. After fixation in glutaraldehyde phosphate buffered solution at 4.0°C, the sections were dehydrated with acetone and dried. After drying to the critical point of dryness, the endothelium was examined by scanning electron microscopy. The results obtained were as follows: 1. Histological examination of corneal epithlium and corneal endothelium. The cornea of the control eyes was composed of the outermost surface layer with a flat 2-layered structure of superficial cells, the middle layer with a 2-to-3-layered structure of polygonal wing cells and the innermost layer with a tall single-layered structure of basal cells. The Bowman's membrane was lightly stained. Its stroma was composed of collagen fiber bundles arranged tightly in layers and a few keratocyte cells. The corneal endothelial cells were in contact with the anterior chamber via the Descemet's membrane. The irradiated eyes developed ciliary injection and iritis immediately after irradiation. These symptoms persisted until 120 hours later. Light microscopy revealed detachment of surface cells and disarrayed formation of wing cells.
Dielectric properties of cacao butter on the wide range of electric frequency were measured and compared with those of some other fats, namely coconut oil, palm oil, tallow, mixed cacao butter with coconut oil and with palm oil. At temperatures above 20°C, the dielectric ε, data of these fats were generaly the same except for coconut oil having a slightly higher value. However temperatures below 20°C, the data extremely fell except for palm oil and tallow due to the glyceride composition containing a certain amount of S3. The ε data of the mixed cacao butter with other fats indicated between each fat in proportion to its mixed ratio. Dielectric Tan δ of these fats were characteristic increased in the range of the lower frequency, and then, The Tan δ of cacao butter and palm oil were remarkably increased at high temperatures although coconut oil and tallow were only slightly increased. However at low temperatures, Tan δ of cacao butter also indicated a higher value, but that of palm oil was not increased. In my opinion that difference was due to the glyceride composition of these fats. The reason is thought to that these two fats also have a S2U glyceride composition but cacao butter is symmetrical S2U and palm oil is not. Then, Tan δ of the other mixed fats also indicated a lower value. It was considered that the measurement of the dielectric ε and Tan δ technique is useful for judging the quality of cacao butter.
The filtration of respirable particles by an absorbent gauze, one of the most popular mask materials, was examined from the standpoint of its hygienic validity. The ambient particulate matter with a diameter of less than 2.1μm was collected by rearranging the Andersen sampler stages. It was found that the collection efficiency of 10 layers of absorbent gauge was only 15% with respect to those res pirable particles. It is concluded that the effectiveness of an absorbent gauge mask is not sufficient because 85% of respirable particles in the ambient air will brake through it.