In order to perform safe and effective electric stimulation in acupuncture analgesia or therapy, basic knowledge concerning the electric stimulator is required. If direct current is used, a negative square wave with a pulse duration of 0.5~1.5 msec should be applied to the needle electrode to perform elective stimulation. Negative current is more effective at lower amperage than positive current and the possible corrosion hazard by the positive current can be avoided.
With the experimental apparatus designed and made available by Nicholes, we evaluated the bacterial filtration efficiency (B.F.E.) of the non-woven fabric and cotton cloth masks. The apparatus was supplied by Nicholes (U.S. Military Specification 36954 C mask, surgical, disposable). The study presented here was performed as a round robin test with Nicholes. By using this apparatus, comparison was made as to the B.F.E. of the six different kinds of surgical face mask before and after prolonged use. The result was obtained that the disposable mask made of glass fiber mat combined with non-woven fabric proved to be the highest in performance with a B.F.E. of 98.1-99.4%. It is useful both in preventing hospital infection and in general clinical practice. The B.F.E. of the conventional cotton cloth masks is not only lower but variable over a wide range of 43.1-93.6%.
Forty species belonging to 14 genera of the family Muscidae were found so far in Korea. They are described in this paper and 5th sternites, forceps and male genitalia are illustrated. Eleven species recorded by Kobayashi (1918-1940) and 16 species by Hori (1952) were revised and redescribed in this paper. The key to the species of the muscid flies in Korea are also presented.
Three parts were distinguished by electron microscopy and by enzyme histochemistry at the boundary zone between the white and red pulp of the human spleen. The first was the inner layer of the perifollicular region, composed of medium-sized lymphocytes with abundant free ribosomes in their cytoplasm. A small number of reticulum cells intervened among these lymphocytes. This inner layer was considered to correspond to the “Follikelaussenzone” (Strasser). The second was the outer layer of the perifollicular region, composed of a meshwork of reticulum cells with reticular fibers, and sheathed and non-sheathed arteries. Small and medium-sized lymphocytes, granulocytes, erythrocytes, platelets, and a small number of plasma cells were observed in the mesh spaces. This outer layer was considered to correspond to the “marginal zone” (Snook). At the outermost part of this layer, the venous sinus appeared. There was no distinct border between this layer and the reel pulp. The third was the neighboring region of the periarterial lymphoid sheath, showing similar structure and cellular components to the outer layer of the perifollicular region. It was characteristic feature for the lymphocytes and some of the reticulum cells of this region to have a strong activity for alkaline phosphatase reaction, while the lymphocytes of the outer layer showed only a weak activity. Adenosine triphosphatase and 5'-nucleotidase activities were demonstrated on the lymphocytes of these three parts of the boundary zone as well as the lymph follicle. Different activities for these enzyme reactions may indicate the functional proper ties of the B-cell system.
Twenty-one clinically normal human mandibular condyles were examined by histologic and microradiographic methods obtaining some measurements. The histological structures of condyle were quite different between the child group and other aged groups. The difference in the surface articular zone composed of the fibrous tissue was not so great in all age groups, while there was quite a difference in the structure in the remaining zones. It was clearly demonstrated by microradiogram that the osteons of the subarticular bone plate were more prominent in aging. Abnormal structures of the condyle were revealed in some individuals of the adult and old age groups, which were assumed probably to be the reactive remodelling against the functional changes of the temporomandibular joint.
The effect of some agents on the antimicrobial activity of ammoniacal silver nitrate, an endodontic medicament, was tested with Streptococcus faecalis by the serial tube dilution method, Its results indicated that sodium hypochlorite, hydrogen peroxide, and blood had a marked inhibitory effect. However, the presence of dentin, necrotic tissue, saliva, and hydrogen sulfide gas liberated from protein decomposition showed no or little effect on the antibacterial properties of this chemical. Since antiseptics or antibiotics generally may be decomposed by necrotic tissues, these findings suggested that the use of ammoniacal silver nitrate not only may resolve the problem of recalcitrant cases in endodontic treatment but also may simplify the disinfecting procedure for root canals.