This research was conducted to investigate the correlations between urinary mercury concentration and each independent variable related with urinary mercury levels. the urinary mercury concentrations of 543 workers exposed to metal mercury vapor in a total of 11 fluorescent lamp manufacturing factories and at the same time mercury concentrations in air were measured from June 1989 to December 1989. And annually mercury consumption per workers, mercury consumption per lamp, numbers of breakage lamps, frequency of mercury infusion, numbers of droppers, and numbers of vacuum exhaustion pumps were also investigated. The results were as follows: 1. The geometric mean of airborne mercury concentration in a total of 11 factories was 47.9 microgram/m3 (5.8~352.2 microgram/m3), six factories(54.5%) of them were exceed the threshold limit value(50.0 microgram/m3). 2. The geometric mean of urinary mercury concentration among 543 workers was 84.3 microgram/l (1.13~533.9 microgram/l), the distribution of workers by urinary mercury concentration showed that 26 workers(4.8%) were above the mercury posioning level(300 microgram/l). 3. The correlation coefficient between urinary mercury concentration and monthly numbers of breakage lamps was the highest(0.74) and next was mercury consumption per lamp (0.67), annually mercury consumption per worker(0.63) in order.
Korea* ; Vacuum

Symptomatic spinal epidural gas-containing cystic lesion is a rare clinical disease entity. We recently experienced two cases of symptomatic epidural gas-containing cysts that were the main cause of the patients?radiculopathy and the cysts were removed surgically. These lesions were actually gas containing ruptured disc herniations from the vacuum discs at the same level. We report herein on the radiological findings along with conducting a review of the related literature.
Spine ; Vacuum

In order In interpret the relationship among many variables, urinary mercury and at the same time mercury concentration in air were measured for 254 workers of a fluorescent lamp manufacturing factory. And monthly mercury consumption amounts, numbers of monthly producing fluorescent lamps, numbers of inferior lamps and numbers of breakage lamps, numbers of vacuum exhaustion pumps and frequencies of mercury infusion were also investigated from January 1988 to March in 1989. The results were as follows; 1. On the mercury concentration in air by producing line and by working site, all of them were exceed the threshold limit value (0.05mg/m(2)). 2. The highest mercury concentration in air by sampling point was found at the floor of workplace (0.334mg/m(2)) and next were at vacuum exhaustion pimp (0.183mg/m(2)), and breathing zone of workers (0.103mg/m(2)) in order. 3. The highest mean of the mercury concentration in urine by producing line was the automatic exhausting line (80.8microgram/1) and next were high speed exhausting line (72.4microgram/1), and Manual exhausting line (35.8microgram/1) in order. Distribution of workers of the mercury concentration in urine more than 200microgram/1 by working site was the highest (10%) in the vacuum exhaustion pump part and next were sealing part (6.6%), packing part (4.6%), and stem part (4.1%) in order. 4. The correlation coefficient between mercury concentration in urine and in air was the highest (0.302) and next were numbers of breakage lamps (0.223), frequencies of mercury infusion (0.223), numbers of inferior lamps (0.205) in order.
Respiration ; Vacuum

No abstract available.
Humans ; Infant, Newborn ; Vacuum

No abstract available.
Skin ; Transplants ; Vacuum

No abstract available.
Intervertebral Disc* ; Vacuum*

No abstract available.
Intervertebral Disc* ; Vacuum*

No abstract available.
Capillaries* ; DNA* ; Vacuum*

This study evaluated the effect of dagassing on the ceramic bond strength of two Ni-Cr alloys under varying holding time at the upper limit temperature and atmospheric conditions. Metal specimens were divided into 5 groups for each alloy according to degassing conditions prior to porcelain application : no degassing, degassing under vacuum without hold, degassing under vacuum with hold for 5min. and 10 min. respectively at the upper limit temperature and degassing in air. Total number of metal ceramic specimens was eighty and each group had eight specimens : The ceramic bond strength was measured by four-point flexural test using Instron and the fractured surface was examined under SEM. The results obtained were as follows. 1. Degassing in air improved the ceramic bond strength of Ni-Cr alloys. 2. in degassing under vacuum, hold at the upper limit temperature was advantageous to the ceramic bonding of Ni-Cr alloys. 3. After ceramic metal bond test, metal surfaces were partially covered with the thin porcelain layer, and the cohesive failures in porcelain were predominant in groups showing higher ceramic bond strength.
Alloys* ; Ceramics* ; Dental Porcelain ; Vacuum

PURPOSE: This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS: Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS: The mean and standard deviations of the failure load were 1,170.1 +/- 90.9 N for EV design and 1,450.4 +/- 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION: There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.
Bicuspid ; Crowns* ; Dental Porcelain ; Vacuum