Dental restorative materials must have the physical properties to withstand wear and corrosion. Base metal alloys possess better mechanical properties and lower price than the gold alloys. For these reason such alloys have largely replaced the precious metal alloys. One aspect to consider is the release of metal substances to oral environment. The release of elements from dental alloys is a continuing concern because the elements may have the potentially harmful biological effects on local tissue. The purpose of this study was to minimize metal release on the nonprecious metal surfaces by ion bea assisted deposition(IBAD) of titanium nitride (TiN). Ni-Cr-Be alloys with and without TiN coatings were secured in an wear test machine opposing ruby ball to determine their relative resistance to wear with 100m, 200m, 300m and 400m sliding distance. And the corrosion behavior of the Ni-Cr-Be alloys with and without TiN coating and 3 dental noble alloys have been studied. Potentiodynamic curves were used to analyse the corrosion characteristics of the alloys. The measurement of the released Ni and Ci ions was conducted by analysis of the electrolyte solution with atomic absorption spectroscopy. The results were as follows : 1. The critical sliding distance that wore down TiN coating of 2.5micrometer thickness in this study condition was 300m. 2. Ion beam assisted deposition of TiN showed a good surface modification with respect to the properties of wear and corrosion resistance. 3. X-ray diffraction showed that the strongest peak of TiN(111) in the coatings. 4. The release of Ni and Cr ions from alloys measured by means of atomic absorption spectroscopy was reduced by ion beam assisted deposition of TiN.
Absorption ; Alloys* ; Corrosion ; Dental Alloys ; Gold Alloys ; Ions ; Spectrum Analysis ; Tin* ; Titanium ; X-Ray Diffraction

No abstract available.
Spinal Muscular Atrophies of Childhood*

No abstract available.
Ciliary Motility Disorders*

In this report we describe twenty-two cases of intracranial tumors studied with an MR imager operating at a field strength of 0.064 T for evaluation of the clinical utility of low tesla MRI. The comfirmed diagnoses were meningioma(9 cases), astrocytoma(4 cases), glioblastoma multiforme(1 case), craniopharyngioma(2 cases), intracranial metastasis(1 case). pituitary microadenoma (1 case), hemangioblastoma (1 case), and trigerminal neurilemmoma(1 case). Meningiomas appeared as well-marginated, homogenous signal intensity masses(67%) in most cases. Most meningiomas showed iso-signal intensity(78%) on T1-weighted images, and high signal intensity on T2-weighted images. After Gd-DTPA enhancement, diffuse homogeneous contrast enhancement(75%) was well see. The multiple hemorrhagic foci within the glioblastoma multiforme were identified, which shoed high signal intensity on T1-weighted images and low signal intensity on T2-weighted images(intracellular methemoglobin), or high signal intensity on both T1 and T2-weighted images(extracellular methemoglobin). One case of cerebellar hemangioblastoma was a well-defined cystic mass with contrast enhanced mural nodule but no identification of characteristic signal void vessels. The remianing tumors showed low signal intensity on T1-weighted images, and high signal intensity on T2-weighted images. Gd-DTPA enhancement was helpful in separating the lesion from the surrounding edema or normal tissue, but had limited diagnostic value in characterizing the nature of the mass. The advantages of low tesla MRI are as follows on requirement of cooling water or electricity, open design, shorter T1 relaxation time compared with high tesla unit that increases the difference of T1-relaxation time between tissues, ease of installation, and cost effectiveness. In conclusion, the low tesla MRI is useful for the detection and evaluation of the brain tumors.
Brain Neoplasms ; Cost-Benefit Analysis ; Diagnosis ; Edema ; Electricity ; Gadolinium DTPA ; Glioblastoma ; Hemangioblastoma ; Magnetic Resonance Imaging ; Meningioma ; Relaxation ; Water

The metal ceramic crown is currently the most popular complete veneer restoration in dentistry, but in many cases, the metal cervical collar at the facial margin is unesthetic and unacceptable. Facial porcelain margin has been used in place of it. But this dose not solve the problems, such as dark gingival discoloration and cervical opaque reflection of porcelain veneer. Recently, metal copings which were designed to terminate its labio-cervical end on the axial walls coronal to the shoulder have been clinically used to solve the esthetic problem of metal ceramic crown. But in this design, porcelain veneer of labio-cervical area which is not supported by metal may not be able to resist the stress during cementation and mastication. The purpose of this study was to evaluate fracture strength and fractured appearance of crowns according to different coping designs. A resin maxillary left central incisor analogue was prepared for a metal ceramic crown, and metal dies were made with duplication mold. Metal copings were made and assigned to one of four groups based on facial framework designs: group 1, coping with 0.5mm metal collar; group 2, metal extended to the shoulder; group 3, metal extended to 1 mm coronal to the shoulder; group 4, metal extended to 2mm coronal to the shoulder. Copings and crowns were adjusted to be same size and thickness, and cemented to metal dies with zinc phosphate cement by finger pressure. Fracture strength was measured with Instron Universal Testing Machine. Metaldies were anchored in Three-way-vice at 3mm below finish line and at 130degree inclined to the lone axis of the crown. Load was directed lingually at 2mm below midincisal edge. Load value at initial crack and at catastrophic fracture was recorded. The results obtained were as follows: 1. Fracture strength values at initial crack were higher in groups 1, 2 than in groups 3, 4 but this difference was not statistically significant(P<0.05). 2. Conventional metal collared crown had greater catastrophic fracture strength than any other collarless crowns. 3. The greater the labial metal coping reduction, the lower the catastrophic fracture strength of crowns but when more than 1mm of labial metal reduction was done, the difference in strengths was not statistically significant(p<0.05). 4. The strongest collarless coping design was group 2.
Axis, Cervical Vertebra ; Cementation ; Ceramics* ; Crowns* ; Dental Porcelain ; Dentistry ; Fingers ; Fungi ; Incisor ; Mastication ; Shoulder ; Zinc Phosphate Cement

BACKGROUND: The potential adverse effects of ketamine in neurosurgical anesthesia have been well established. However, the effects of ketamine on intracranial pressure (ICP) and hemodynamics during general anesthesia remain unclear. The purpose of this study was to assess the effects of ketamine on hemodynamics and ICP in anesthetized, ventilated rabbits. METHODS: Thirty rabbits were divided into three groups: Group 1 (n=10) received 1 ml/kg normal saline iv; Group 2 (n=10) received 0.5 mg/kg ketamine iv; Group 3 (n=10) received 1.0 mg/kg ketamine iv. After induction with thiopental, anesthesia was maintained with isoflurane and nitrous oxide in oxygen. During controlled ventilation, ICP, mean arterial pressure (MAP), cerebral perfusion pressure (CPP) and heart rate (HR) were measured. The ICP was measured using Ladd ICP monitoring system. All variables were evaluated at baseline and for 30 min following ketamine. RESULTS: In group 1, ICP, MAP, CPP and HR were unchanged over the course of the study. In group 2, ICP, MAP and CPP were unchanged. HR increased at 1, 3 and 5 min (p<0.01), 10 and 20 min (p<0.05) after injection. In group 3, ICP, MAP and CPP increased at 1 and 3 min (p<0.01) after injection. HR increased at 1, 3 and 10 min (p<0.01), 5 min (p<0.05) after injection. CONCLUSIONS: These results suggest that 0.5 and 1.0 mg/kg of ketamine don't significantly affect the hemodynamics and ICP in anesthetized, mechanically ventilated rabbits.
Anesthesia* ; Anesthesia, General ; Arterial Pressure ; Heart Rate ; Hemodynamics* ; Intracranial Pressure* ; Isoflurane ; Ketamine* ; Nitrous Oxide ; Oxygen ; Perfusion ; Rabbits* ; Thiopental ; Ventilation

No abstract available.
Animals ; Rats* ; Somatotrophs*

No abstract available.
Acetabulum* ; Arthroplasty, Replacement, Hip*

A case of amelia, which affected upon both lower extremities, was experienced at the Taegu Presbyterian Hospital. We report this case because of rarity of amelia and an addition of the case with brief review of literatures.
Daegu ; Ectromelia ; Lower Extremity ; Protestantism

BACKGROUND: Hereditary spherocytosis(HS) is a clinically and biochemically very heterogeneous disorder The purpose of this study is to detect erythrocyte membrane protein abnormalities by SDS-PAGE and to investigate the frequency of erythrocyte membrane protein defects in hereditary spherocytosis and correlation between some of the hereditary spherocytosis biochemical subsets and the selected clinical phenotype. METHODS: We evaluated the clinical and laboratory characteristics of 14 normal healthy persons and 23 hereditary spherocytosis patients and 8 their family members. The patients were divided into three groups based on clinical and hematological severity(mild, typical, severe). In addition to routine hematologic determlnatlons, osmotic fragility and autohemolysis, RBC membrane protein analysis were performed in all patients by densitometric tracing of SDS-PAGE(sodium dodecyl sulphate polyacrylamide gel electrophoresis) stained by Coomassle blue utilizing both the discontinuous buffer system of Laemmli with acrylamide linear gradient from 4% to 12% and the continuous buffer system of Fairbank with exponential gradient of acrylamide from 3.5% to 17%. RESULTS: 1) The patients could be seperated into three classes of different clinical severity as mild(3 cases), moderate(16 cases) and severe(4 cases) on the clinical feature. 2) Eighteen patients(82.6%) among 23 hereditary spherocytosis revealed abnormal erythrocyte membrane protein and we detected six patients(26.1%) with spectrin deficiency combined with ankyrin reduction, 4 patients(17.4%) with ankyrin deficiency, 4 patients(17.4%) with isolated spectrin deficiency and 3 patients(13.0%) with band 3 deficiency. Five HS patients(21.7%) showed normal RBC membrane protein. 3) Eight HS and their family members showed same RBC membrane protein deficiency. 4) The type and degree of RBC membrane protein reduction were variale with spectrin at 66~94%, with ankyrin at 48~82% of normal levels. These showed that each patient had different clinical severities according to different RBC membrane protein levels and type. CONCLUSION: RBC membrane protein abnormalities were observed in 82.6% of HS patients. The combined spectrin and ankyrin deficiency is the most common molecular defect in HS. The clinical severity and biochemical expression is heterogeneous. SDS-PAGE analysis of RBC membrane protein was provided the diagnosis of RBC membrane defects and basic molecular studies. We believed that the early identification of the biochemical defect responsible for HS is important because it is helpful starling point for the identification of the primary molecular defect, and it could help to anticipate the clinical outcome of the disease. For these reasons, we consider the SDS-PAGE of the red cell membrane to be of crucial importance for a complete evaluation of children with HS. Further studies with more cases would be to clarify the correlation between clinical and biochemical phenotypes.
Acrylamide ; Ankyrins ; Cell Membrane ; Child ; Diagnosis ; Electrophoresis, Polyacrylamide Gel* ; Erythrocyte Membrane* ; Erythrocytes* ; Erythrocytes, Abnormal ; Humans ; Membrane Proteins ; Membranes ; Osmotic Fragility ; Phenotype ; Population Characteristics* ; Spectrin ; Starlings