In order to understand the pathogenesis and progression of some synaptic loss related neuropsychiatric diseases. We attempted to develop a computer model in this study. We made a simple autoassociative memory network remembering numbers, transformed it into a disease model by pruning synapses, and measured its memory performance as a function of synaptic deletion. Decline in performance was measured as amount of synaptic loss increases and its mode of declines is sudden or gradual according to the mode of synaptic pruning. The developed computer model demonstrated how synaptic loss could cause memory impairment through a series of computer simulations, and suggested a new way of research in neuropsychiatry.
Computer Simulation* ; Dementia ; Memory ; Neuropsychiatry ; Schizophrenia ; Synapses

No abstract available.

Image resampling is of particular interest in digital radiology. When resampling an image to a new set of coordinate, there appears blocking artifacts and image changes. To enhance image quality, interpolation algorithms have been used. Resampling is used to increase the number of points in an image to improve its appearance for display. The process of interpolation is fitting a continuous function to the discrete points in the digital image. The purpose of this study was to determine the effects of the seven interpolation functions when image resampling in digital periapical images. The images were obtained by Digora, CDR and scanning of Ektaspeed plus periapical radiograms on the dry skull and human subject. The subjects were exposed to intraoral X-ray machine at 60kVp and 70 kVp with exposure time varying between 0.01 and 0.50 second. To determine which interpolation method would provide the better image, seven functions were compared ; (1) nearest neighbor (2) linear (3) non-linear (4) facet model (5) cubic convolution (6) cubic spline (7) gray segment expansion. And resampled images were compared in terms of SNR(Signal to Noise Ratio) and MTF(Modulation Transfer Function) coefficient value. The obtained results were as follows ; 1. The highest SNR value(75.96dB) was obtained with cubic convolution method and the lowest SNR value(72.44dB) was obtained with facet model method among seven interpolation methods. 2. There were significant differences of SNR values among CDR, Digora and film scan(p<0.05). 3. There were significant differences of SNR values between 60kVp and 70kVp in seven interpolation methods. There were significant differences of SNR values between facet model method and those of the other methods at 60kVp(p<0.05), but there were not significant differences of snr values among seven interpolation methods at>0.05). 4. There were significant differences of MTF coefficient values between linear interpolation method and the other six interpolation methods(p<0.05). 5. The speed of computation time was the fastest with nearest neighbor method and the slowest with non-linear method. 6. The better image was obtained with cubic convolution, cubic spline and gray segment method in ROC analysis. 7. The better sharpness of edge was obtained with gray segment expansion method among seven interpolation methods.
Artifacts ; Humans ; Noise ; Radiography, Dental, Digital ; ROC Curve ; Skull

PURPOSE: The purpose of this study was to investigate foot ulcer risk factors, foot care knowledge, and foot care practice in patients with type 2 diabetes. METHOD: One hundred fifty type 2 diabetic patients were in and out-patients in a large urban hospital. The data were collected using a self-report questionnaire, chart review and foot examination. The questionnaires were developed by the researchers through the experts consultation and literature review. High risk for foot ulcer was evaluated by peripheral neuropathy(PN), peripheral vascular disease(PVD), and prior foot ulcer. Foot risk scores(FRS) means numbers of present risk factors. RESULTS: 31.3% of subjects show 1 FRS, and 13.3% showed 2 FRS. Mean foot care frequency was 3.5 times per week. There were significant differences in foot care knowledge according to DM education (t=2.96, p=.004) and foot care education (t=3.65, p=.001). There were significant differences in the foot care practice activities according to duration of DM (t=3.48, p=.010) and educational levels. CONCLUSION: There were high proportion of foot ulcer risk among the patients. It is necessary to screen high risk foot ulcer patients and provide practical education for foot care practice of diabetic patients.
Education ; Foot Ulcer* ; Foot* ; Hospitals, Urban ; Humans ; Outpatients ; Risk Factors ; Surveys and Questionnaires

No abstract available.
Humans ; Infant* ; Parturition*

The purpose of this study was to aid in the use of the digital images by edge-detect interpolation for direct digital periapical images using edge-deted interpolation. This study was performed by image processing of 20 digital periapical images; pixel replication, linear non-interpolation, linear interpolation, and edge-sensitive interpolation. The obtained results were as follows ; 1. Pixel replication showed blocking artifact and serious image distortion. 2. Linear interpolation showed smoothing effect on the edge. 3. Edge-sensitive interpolation overcame the smoothing effect on the edge and showed better image.
Artifacts

PURPOSE: To investigate the regional characteristics and the factors that influence final visual acuity in corneal laceration and use the results for prevention and treatment of corneal laceration. METHODS: Sixty-eight patients who visited the Chosun University Medical Center from January 1, 2006 to December 31, 2010 were retrospectively surveyed. The incidence of corneal laceration, sex, age, monthly and seasonal distribution, cause, site and length of corneal laceration, secondary operation, complications, and ocular trauma score were reviewed statistically. In additional, the factors influencing visual prognosis were investigated. RESULTS: The incidence was more common in males (94.1%) and in the 6th-decade of life (29.4%). The corneal laceration was more common in the summer (38.2%) and in September (26.5%) and the most common cause was stone (39.7%) and metal (35.3%), respectively. The corneal laceration tended to occur at the corneal center. The most common first operation was primary closure (81.9%), and the secondary operation was most often performed due to a traumatic cataract (32.1%). The factors that significantly influenced the final visual acuity were initial visual acuity, length and site of laceration, and secondary operation. CONCLUSIONS: The present survey investigated the regional characteristics and important factors influencing final visual acuity. Results show initial visual acuity, the length and site of laceration, and the secondary operation significantly influenced final visual acuity.
Academic Medical Centers ; Cataract ; Humans ; Incidence ; Lacerations ; Male ; Prognosis ; Retrospective Studies ; Seasons ; Visual Acuity

The purpose of this study was to evaluate the Waters' views, panoramic and periapical radiograms as well as clinic al symptoms in the diagnosis of maxillary sinusitis. The author analyzed the types of mucosal thickenings, the types of bony wall changes, the pathologic changes of antra l floors and total amount of agreement on radiograms in 495 patients with 505 maxillary sinuses which demonstrated radio graphic changes. The results were obtained as follows : 1. 125 cases (24.8%) showed the mucosal thickening of antral floor and lateral wall(Type II), 106 cases (20.9%) showed the mucosal thickening around the whole antral wall(Type IV) and 75 cases (14.8%) showed increased radiopacity of whole antrum. 2. Among 505 cases of mucosal thickening, 319 cases(63.2%) showed the bony wall changes: 114 cases (35.9%) showed the thining of lateral walls, 105 cases(32.8%) showed the thickening of lateral walls and 47 cases(14.7%) showed indistinct antral walls. 3. Among 6 types of mucosal thickenings, the incidence of bony wall changes was high in type VI(73.3%) and in type IV(7 1.6%). 4. 139 cases(25.1%) showed no pathologic change of antral floor, 127 cases(22.9%) showed the indistinct antral floor an d 022 cases (22.1%) showed the halo appearance of antral floor on panoramic and periapical radiograms. 5. 449 cases(88.9%) showed apparent increased radiopacity and 47 cases(9.3%) showed suspicious increased radiopacity on Waters' views. 280 cases(71.6%) showed apparent increased radiopacity and 88 cased (22.5%) showed suspicious increased radiopacity on panoramic radiograms. And 141 cases(31.6%) showed apparent increased radiopacity and 133 cases(33.4%) showed suspicious increased radiopacity on periapical radiograms.
Diagnosis ; Humans ; Incidence ; Maxillary Sinus* ; Maxillary Sinusitis*

The purpose of this study was to evaluate the Waters' views, panoramic and periapical radiograms as well as clinic al symptoms in the diagnosis of maxillary sinusitis. The author analyzed the types of mucosal thickenings, the types of bony wall changes, the pathologic changes of antra l floors and total amount of agreement on radiograms in 495 patients with 505 maxillary sinuses which demonstrated radio graphic changes. The results were obtained as follows : 1. 125 cases (24.8%) showed the mucosal thickening of antral floor and lateral wall(Type II), 106 cases (20.9%) showed the mucosal thickening around the whole antral wall(Type IV) and 75 cases (14.8%) showed increased radiopacity of whole antrum. 2. Among 505 cases of mucosal thickening, 319 cases(63.2%) showed the bony wall changes: 114 cases (35.9%) showed the thining of lateral walls, 105 cases(32.8%) showed the thickening of lateral walls and 47 cases(14.7%) showed indistinct antral walls. 3. Among 6 types of mucosal thickenings, the incidence of bony wall changes was high in type VI(73.3%) and in type IV(7 1.6%). 4. 139 cases(25.1%) showed no pathologic change of antral floor, 127 cases(22.9%) showed the indistinct antral floor an d 022 cases (22.1%) showed the halo appearance of antral floor on panoramic and periapical radiograms. 5. 449 cases(88.9%) showed apparent increased radiopacity and 47 cases(9.3%) showed suspicious increased radiopacity on Waters' views. 280 cases(71.6%) showed apparent increased radiopacity and 88 cased (22.5%) showed suspicious increased radiopacity on panoramic radiograms. And 141 cases(31.6%) showed apparent increased radiopacity and 133 cases(33.4%) showed suspicious increased radiopacity on periapical radiograms.
Diagnosis ; Humans ; Incidence ; Maxillary Sinus* ; Maxillary Sinusitis*

The purpose of this study was to compare E-speed film, CDR, and modified CDR images by means of observing some artificial defects of alveolar bone wall in the sound human dried mandibles. High diagnostic accuracy was shown in 1 wall and 4 wall defects by all 5 observers (2 Radiologists, 2 Periodontists, 1 General practitioner), but the diagnosis in 2 wall and 3 wall defects was inaccurate. Modified CDR images had the more diagnostic accuracy than E-speed film and CDR images, but there was no statistical difference among them. Finally, radiologist used modified CDR images more than others and used equalization effect more than the change in contrast and/or brightness.
Diagnosis ; Humans ; Mandible ; Radiographic Image Enhancement*