1.Studies on the residues of Nicarbazin in commercial chickens.
Fumi MANDA ; Toshio MATSUSHITA ; Atsushi UEDA ; Mitsuki YOSHIOKA ; Kohji AOYAMA
Journal of the Japanese Association of Rural Medicine 1985;34(2):104-109
A simple and sensitive method for the determination of residual Nicarbazin (NCZ) by high performance liquid chromatography (HPLC) was examined to apply to livestock products. And the detection of residual NCZ in commercial chickens was also investigated.
1. The method that the acetonitrile extracts of meat homogenate were injected directly into HPLC was able to apply to determine the residual NCZ by adding process of degreasing and dehydration of the extracts. The average recovery of NCZ added to the chicken muscle (0.4 μg/g) were 89.13±6.61%(N =5) and detection limit in this analytical procedure was 0.02μg/g.
2. Using the above method for the analysis of NCZ in commercial samples, the frequency of detection was 13.0% and the range of concentration was 0.03-0.30μg/g in samples collected from Kagoshima city (N =131). The residual NCZ in commercial chickens showed a tendency to increase in summer season. The similar levels of frequency (12.5%) and concentrations (0.03-0.43μg/g) were found in samples collected from other prefectures (N=40).
2.Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading.
Manish MISHRA ; Shogo OZAWA ; Tatsuhiko MASUDA ; Fumi YOSHIOKA ; Yoshinobu TANAKA
The Journal of Advanced Prosthodontics 2011;3(3):140-144
PURPOSE: Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading. MATERIALS AND METHODS: Two dimensional finite element models of cylinderical implant, abutments and bone made by titanium or polyoxymethylene were simulated with the aid of Marc/Mentat software. Each model represented bone, implant and titanium or polyoxymethylene abutment. Model 1: Implant with 3 mm titanium abutment, Model 2: Implant with 2 mm polyoxymethylene resilient material abutment, Model 3: Implant with 3 mm polyoxymethylene resilient material abutment and Model 4: Implant with 4 mm polyoxymethylene resilient material abutment. A vertical load of 11 N was applied with a frequency of 2 cycles/sec. The stress distribution pattern and displacement at the junction of cortical bone and implant was recorded. RESULTS: When Model 2, 3 and 4 are compared with Model 1, they showed narrowing of stress distribution pattern in the cortical bone as the height of the polyoxymethylene resilient material abutment increases. Model 2, 3 and 4 showed slightly less but similar displacement when compared to Model 1. CONCLUSION: Within the limitation of this study, we conclude that introduction of different height resilient material abutment with different heights i.e. 2 mm, 3 mm and 4 mm polyoxymethylene, does not bring about significant change in stress distribution pattern and displacement as compared to 3 mm Ti abutment. Clinically, with the application of resilient material abutment there is no significant change in stress distribution around implant-bone interface.
Dental Implants
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Displacement (Psychology)
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Finite Element Analysis
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Titanium