Event related potentials were recorded on the human scalp during a foot pedal task, a hand gripping task, and a teeth clenching task. These were carried by targeting four trains of clicks, each at an interval of 1 sec, which were repeated 20 times at random frequencies. The brain potentials were recorded from midline-frontal (Fz), -central (Cz) and -parietal (Pz) sites using surface electrodes. Positive potentials like P3 were elicited predominantly at the frontal site (Fz); those for the clenching task were slower and smaller. The magnitudes of the P3 potentials showed rough facilitation with trains of movement of the tasks. If it is assumed that the observed potentials involve an inhibition or reset of motor neurons referring to the tasks, the facilitation might be expedient for the neurons to recover the potential condition more quickly, which is important in preparing for the next action.

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The perceptibility curve test is a method for evaluating the psychophysical properties of radiographic systems. The concept of the perceptibility curve is based on the minimum perceptible exposure differences that are recorded by a particular imaging system. The perceptibility curve test was applied to a Charge-Coupled Device (CCD)-based digital intraoral radiography system in this study. A test object was made of a square aluminum block, 28mm in both height and length and 10mm in thickness. The test object had ten contrast details in the form of round holes with diameters of 1.5mm. The depths of the holes ranged from 0.05mm to 0.5mm in steps of 0.05±0.01mm. An X-ray unit was used that operated in the range of 60 to 90kVp. Test radiographs were shown to observers in random order. Six observers were asked to rate them regarding the number of spots representing holes that they could perceive. The smallest perceptible difference in gray level on the computer monitor, a 15-inch cathode-ray tube (CRT), was then found. The minimum difference in gray level between a perceptible detail and the background was determined. Dose response functions were employed to determine exposures corresponding to these gray levels. For each case, ΔlogE as a function of the number of object details was calculated. Finally the reciprocal of all values of (ΔlogE)_min were calculated. The number of details which the observers perceived decreased linearly with decreasing ΔlogE values. The maximum number of details that observers perceived was eight or nine. The perceptibility curves showed that their peaks shifted slightly with a change of the kVp but that their shapes were similar at different kVp settings.

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The short tandem repeat (STR) polymorphism of the locus D12S66 was amplified by PCR and analyzed by denaturing polyacrylamide gel electrophoresis followed by silver staining. Among 190 DNA samples from the Japanese population, six alleles were observed. The genotypic distribution meets Hardy-Weinberg expectations, and the heterozygosity was 52.7%. When sequences of the allelic products were compared, each allelic segment was 153-173bp in size, and contained 9 to 14 GATA tetranucleotide repeat motifs. Amplification of the locus using 27 tooth and blood stain samples as sources of degraded DNA resulted in low backgrounds and reproducible patterns, suggesting the usefulness of the application of this locus for material examination.

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A case of maxillary carcinoma treated with primary insertion of Brånemark implants into the zygomatic bone following subtotal maxillectomy is reported. This method has several advantages. First, early detection of postoperative recurrence is easier than with closing the flap. Second, when the implant is inserted into the midfacial region, zygomatic bone can be useful because of thickness. In addition, applying a maxillary prosthesis in the early stages avoids contracture of facial soft tissue. This primary reconstructive method is effective in cases of preservated zygoma after total maxillectomy.

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