Fractures of the mandible occur with a greater frequency in the elderly. This study reports three cases of edentulous atrophic mandible fracture in elderly patients treated with open reduction technique. Three patients who presented with edentulous atrophic mandible fractures underwent surgical management using open reduction and internal fixation. After treatment, clinical evaluations and postoperative complications were examined with postoperative x-ray. Patients were followed with clinical and radiographic examinations. In the postoperative clinical evaluation, two male patients healed well, but one female patient complained of pain and swelling. In radiographic examinations, no union delay or lack of fusion was observed in the edentulous area. Open reduction technique is a viable treatment option for the edentulous atrophic mandible fractures in geriatric patients.

Repetitive plate-loading test is intended to identify the elastic modulus of a target structure subjected to dynamic loading; such tests are mainly applied to railway roadbeds. The repetitive plate-loading test uses the same equipment as the plate-loading test but different loading methods. The plate-loading test derives the subgrade reaction modulus (k30), while the repetitive plate-loading test derives the strain modulus (Ev2). The former considers the scale effect of the loading-plate size, whereas the latter does not, thereby reducing the reliability of the results. Therefore, numerical analysis was conducted to propose a scale effect that can applied to field tests. First, to verify the 50-mm loading plate, a previous study comparing the results of the 300-mm loading plate in a field test was simulated by a numerical analysis, and the results were compared and analyzed. Next, the strain modulus was investigated according to the loading-plate size under subgrade conditions. An equation to estimate the scale effect applicable to loading plates with diameters of less than 762 mm was derived. The relationship between the calculated strain and elastic moduli was additionally analyzed.

No abstract

Stereoacuity is defined as a correlative order of depth of the object in three dimensional space, with a high degree ability to perceive the depth by using the monocular vision of both eyes. [1][2][3][4][5] Generally, the stereoptic function is decreased when there is strabismus, suppression and amblyopia. The stereoacuity test has been regarded as important because it can confirm the absence of strabismus, suppression and amblyopia, except for intermittent exotropia and anisometropic amblyopia, if the stereoptic function is normal. The stereoacuity test is an important test which is used as an indicator to decide on the operation time and postoperative evaluation.Stereoacuity tests include the Randot test, Titmus-fly, TNO and other related tests. We can test the stereoacuity after separating the binocular vision by using polarized or red-green glasses. However, in an actual clinic it is difficult for a clinical doctor to perform an accurate test in the case of children who hate to wear glasses and have precognition of the test itself. 6-9 A good stereoacuity test should be easy, simple and accurate without rejection. Nevertheless, most of the stereoacuity tests are Existing methods of stereoacuity testing need specific glasses or optical device for use. We have designed a new stereoacuity test for the digitalized, random-dot stereogram and researched its clinical usefulness. A digitalized, random-dot, stereoacuity test card was created with a computer program that used a preferred symbol and the designed system was tested along with the Randot preschool stereoacuity, Titmus-fly and Lang tests to compare their sensitivity and specificity. The mean success rate of the digitalized, random-dot test was 98.2%, while the rates of the Randot preschool stereoacuity, Titmus-fly and Lang tests were 89.3%, 74.2% and 86.1%, respectively. Sensitivity and specificity of the new test were 100% and 95.3%, respectively, which were not that different from those of the Randot preschool stereoacuity, Titmus-fly and Lang tests. We found that the digitalized, random-dot, stereoacuity test has a high success rate and can be appropriately used in medical examinations and follow-up tests for strabismus patients.

Reinforced soil retaining wall are ground structures that can be readily seen all around us. The development of reinforcements to these walls and their demand have increased rapidly. These walls are advantageous because they can be used not only in simple construction compared with reinforced concrete retaining walls but also when the height of the wall needs to be higher. However, unlike reinforced concrete retaining walls, in which the walls are integrated and resist the earth pressure on the back, the block-type reinforced earth retaining wall method secures its structural stability by frictional force between the buried land and reinforcements. A phenomenon in which a block is cracked or dropped owing to deformation has been frequently reported. In particular, this phenomenon is concentrated at the curved parts of a reinforced soil retaining wall and is mainly known as a stress concentration. However, to date, the design of reinforced soil retaining walls has been limited by the two-dimensional plane strain condition and has not considered the characteristics of the curved part. There is a lack of research on curved part. Therefore, this research determines the behavioural characteristics of curved-part reinforced soil retaining walls with regard to the shape (convex or concave) and angle (60°, 90°, 120°, and 150°). The displacement generated in the straight part and the curved part was analysed through an Laboratory Scale Test. The results showed that the horizontal displacement of the curved part increases as a convex angle becomes smaller, and the horizontal displacement of the curved part decreases as a concave angle becomes smaller. At the center (D and H have the same length, but H represents the height and D represents the separation distance from the center of the curved part) of the convex curve, the horizontal displacement of the 0.5 D section decreased to 13.8%; it decreased to 41.0% in the 1.0 D section. For concave angles, it was revealed that the horizontal displacement from the center 0.0 D to the 0.5 D section of the curved part increased by 25%, and from the 1.0 D section, by 75%. It was confirmed that the displacement difference was largely based on the value of 0.5 D. It was judged that this can be used as basic data for the design and construction guidelines for reinforced soil retaining wall of reinforced soil retaining walls.