• Journal of Chest Surgery
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• 제21권2호
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• pp.389-394
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• 1988

The patient was 22-year old male who had been suffered from labored breathing. Computerized tomography, tracheoscopy, tracheogram disclosed tracheal obstruction by external mass compression on Tl level, which ranged 4.Oem in the length and approximately 4mm in diameter on tracheogram. Under the local anesthesia, tracheostomy was done to prevent intraoperative airway obstruction. And general anesthesia, low collar incision 8z extended median sternotomy was made and nearly total thyroidectomy was performed. After the circumferential resection of the obstructed segment approximately 4cm in length[7 tracheal rings], direct end-to-end anastomosis of trachea was performed. Postoperatively, the patient`s neck was maintained in flexion state to reduce tension of anastomotic site. Postoperatively. medical therapy[Comthyroid k Calcium lactate] and radiotherapy were done. At present, 2-months after operation, he lives well.

• 설비공학논문집
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• 제15권7호
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• pp.611-617
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• 2003

The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate the characteristics of the air-side particulate fouling materials in finned-tube heat exchangers of air conditioners. Air conditioners being used in the field such as inns, restaurants, and offices are collected in chronological order in use. Typical fouling materials on the heat exchangers include fibers and dusts ranged from 6.6 to 20.9 ${\mu}{\textrm}{m}$ in mass median diameter.

• 천문학회보
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• 제40권2호
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• pp.45.3-46
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• 2015

Space weathering agents such as micrometeoroids and solar wind particles continuously age the uppermost regolith of the lunar surface by comminuting as well as darkening and reddening. Among several maturity indices, we investigate median grain size () and optical maturity (OMAT) of the crater rim walls. Crater rim wall is the most immature place among the impact crater features because the vertical mixing process by mass-movement can enhance the gardening of regolith and the supply of immature materials in the deeper layer to the surface. More than 140 simple and complex craters were considered. Both and OMAT values of the inner rim wall initially increase as the crater size increases until ~10-20 km, then decrease. This transition crater size happens to correspond to the transition diameter from simple to complex craters. For larger craters, i.e., complex craters, it is clear that the inner rim wall of the craters formed in recent eras tend to remain fresh and become mature along with time. For the simple crater case, smaller craters are more mature, which is opposite to the case of complex craters. This is thought to be because smaller craters become flattened more quickly, thus have smaller vertical mixing in the regolith due to mass-movement. We will also discuss on the maturity indices of the crater rim walls at high latitudes as a function of the position angle to see the latitude dependence of the space weathering process.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.532-537
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• 2000

The purpose of this study is to determine the performance of a commercial air cleaner in removing tobacco smoke indoors. Following injection of tobacco smoke in a room, decay rates for particle concentrations were obtained far mass concentration at each point. The size distribution of the tobacco smoke particles was approximately $1.266{\mu}m$ in mass median diameter with a geometric standard deviation of 1.313. The air cleaner consisted of an electrostatic filtration unit and a fan operated at a flow rate of 5.98 CMM. The collection efficiency for $>1\;{\mu}m$ was more than 99%. Without air cleaner operation, tobacco smoke concentration ratio in room decreased to 30% of initial values within 30 minutes and with air cleaner operation, decreased to 90% of initial values in the test chamber, volume $51.27\;m^3$. Without air cleaner operation, tobacco smoke concentration ratio in room decreased to 10% of initial values within 30 minutes and with air cleaner operation, decreased to 30-70% of initial values in the test chamber, volume $149.2\;m^3$.

• 한국수정란이식학회지
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• 제32권1호
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• pp.33-38
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• 2017

A 10-day-old, Holstein calf with facial mass of 10 cm in diameter at the forehead region referred to Veterinary Medical Teaching Hospital in Chungnam National University. The mass was soft and fluctuating swelling. It had normal skin and hair hanging forward from frontal region and was thought to contain cerebrospinal fluid. On the skull radiography, cauliflower like-irregular marginated, soft tissue opacity mass was identified craniodorsal to the frontal bone. The mass appeared as a cyst filled with anechoic fluid on ultrasonography. Soft tissue structures considered brain tissues were observed in the deep area of the mass. On the computed tomography, a large skull defect of left side frontal bone was found, and heterogeneous materials were exposed through the defect but exposure of cerebral meninges and brain tissue were not confirmative. On magnetic resonance imaging, herniated left brain parenchyma showed heterogenous T2 and T1 hyperinsensity. In the intracranium, T2 hyperinstense and T1 hypointense fluid was identified on the left side, instead of left cerebral parenchyma. Also leftward shift of right hemisphere and midline structure, including thalamus and midbrain, were observed. The definitive diagnosis was confirmed as a meningoencephalocele based on computed tomography and magnetic resonance imaging. The calf was euthanized and necropsy was performed. On necropsy, both hemisphere were developed unequally with different size. One side hemisphere was grown in the outside through 10 cm hole on the median plane.

• 분석과학
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• 제34권2호
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• pp.87-98
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• 2021

In this study, we developed the nanoparticle multi-generator by 3D printer fusion deposition modeling (FDM) method that can reliably generate and deliver nanoparticles at a constant concentration for inhalation risk assessment. A white ABS filament was used as the test material, and SMPS was used for concentration analysis such as particle size and particle distribution. In the case of particle size, the particle size was divided by 100 nm or less and 100 to 1,000 nm, and the number of particles concentration, mass concentration, median diameter of particles, geometric average particle diameter, etc were measured. The occurrence conditions were the extruder temperature, the extruding speed of the nozzle, and the air flow rate, and experiments were conducted according to the change of conditions including the manufacturer's standard conditions. In addition, the utility of inhalation risk assessment was reviewed through a stability maintenance experiment for 6 h. As a result of the experiment, the size of the nanoparticles increased as the discharger temperature increased, as the discharge speed of the nozzle increased, and as the air flow rate decreased. Also, a constant pattern was shown according to the conditions. Even when particles were generated for a long time (6 h), the concentration was kept constant without significant deviation. The distribution of the particles was approximately 80 % for particles of 60 nm to 260 nm, 1.7 % for 1 ㎛ or larger, 0.908 mg/㎥ for the mass concentration, 111 nm for MMAD and 2.10 for GSD. Most of the ABS particles were circular with a size of less than 10 nm, and these circular particles were aggregated to form a cluster of grape with a size of several tens to several hundred nm.

• 동의생리병리학회지
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• 제16권5호
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• pp.1035-1041
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• 2002

Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit and 766ppm Cd nebulizing solution were used to generate cadmium aerosol for inhalation toxicology study. The results of particle size analysis for cadmium aerosol were as following. The highest particle counting for source temperature 20℃ was 43.449 x 10³ in inlet temperature 250℃ and particle diameter 0.75㎛. The highest particle counting for source temperature 50℃ was 43.211 x 10³ in inlet temperature 100 ℃ and particle diameter 0.75㎛. The highest particle counting for source temperature 70℃ was 41.917x10³ in inlet temperature 250℃ and particle diameter 0.75㎛. The ranges of geometric mean diameter(GMD) were 0.677-1.009㎛ in source temperature 20℃, 0.716-0.963㎛ in source temperature 50℃, and 0.724-0.957㎛ in source temperature 70℃. The smallest GMD was 0.677㎛ in source temperature 20℃ and inlet temperature 20℃. and the largest GMD was 1.009㎛ in source temperature 20℃ and inlet temperature 20℃. The ranges of geometric standard deviation(GSD) were 1.635-2.101 in source temperature 20℃. 1.676-2.073 in source temperature 50℃, and 1.687-2.051 in source temperature 70℃. The lowest GSD was 1.635 in source temperature 20℃ and inlet temperature 20℃, and the highest GSD was 2.101 in source temperature 20℃ and inlet temperature 200℃. Aerosol generated for cadmium inhalation toxicology study was polydisperse aerosol. The ranges of mass median diameter(MMD) were 1.399-5.270㎛ in source temperature 20℃. 1.593-4.742㎛ in source temperature 50℃, and 1.644-4.504㎛ in source temperature 70℃. The smallest MMD was 1.399㎛ in source temperature 20℃ and inlet temperature 20℃, and the largest MMD was 5.270㎛ in source temperature 20℃ and inlet temperature 200℃. Increasing trends for GMD, GSD, and MMD were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4㎛. In our results. inlet temperature 20 and 50℃ in source temperature 20℃, and inlet temperature 20 to 150℃ in source temperature 50 and 70℃ were conformed to the EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3㎛. In our results, inlet temperature 20 and 50℃ in source temperature 20, 50, and 70℃ were conformed to the OECD and EU guidance.

• 동의생리병리학회지
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• 제17권2호
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• pp.518-524
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• 2003

Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit was made for lead inhalation toxicology study and 2730ppm lead nebulizing solution was used to generate lead aerosol. After modification of source and inlet temperatures, the results of particle size analysis for lead aerosol were as following. The highest particle counting for source temperature 20℃ was 39933.66 in inlet temperature 100℃ and particle diameter 0.75tLm. The highest particle counting for source temperature 50℃ was 39992.71 in inlet temperature 250℃ and particle diameter 0.75μm. The highest particle counting for source temperature 70℃ was 37569.55 in inlet temperature 50℃ and particle diameter 0.75μm. The ranges of geometric mean diameter(GMD) were 0.754-0.784μm for source temperature 2℃, 0.758-0.852μm for source temperature 50℃, and 0.869-1.060μm for source temperature 70℃. The smallest GMD was 0.754μm in source temperature 20℃ and inlet temperature 20℃, and the largest GMD was 1.060μm in source temperature 70℃ and inlet temperature 250℃. The ranges of geometric standard deviation(GSD) were 1.730-1.782 for source temperature 20℃, 1.734-1.894 for source temperature 50℃, and 1.921-2.148 for source temperature 70℃. The lowest GSD was 1.730 in source temperature 20℃ and inlet temperature 20℃, and the highest GSD was 2.148 in source temperature 70℃ and inlet temperature 250℃. Lead aerosol generated in this study was polydisperse. The ranges of mass median diameter(MMD) were 1.856-2.133μm for source temperature 20℃, 1.877-2.894μm for source temperature 50℃, and 3.120-6.109μm for source temperature 70℃. The smallest MMD was 1.856μm in source temperature 20℃ and inlet temperature 20℃, and the largest MMD was 6.109μm in source temperature 70℃ and inlet temperature 250℃. Slight increases for GMD, GSD, and MMD values were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but inlet temperature 20℃ and 50℃ for source temperature 70℃ were conformed EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but none for source temperature 70℃.

• 동의생리병리학회지
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• 제18권2호
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• pp.474-483
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• 2004

To know the effects between Cd inhalation toxicity and extract of Radix Achyranthis Bidentatae, 4 rat groups were exposed to Cd aerosol in air using whole-body inhalation exposure for 6 hours/day, 5 days/week, and 4 weeks. Cd concentration in air was 1.03㎎/㎥ and mass median diameter(MMD) was 1.69㎛. 3 different dose intraperitoneal injections of extract of Radix Achyranthis Bidentatae to 3 inhalation exposure groups was done for 4 weeks and the results were as follows: The highest body weight gain for 4 weeks and food intake per day were from inhalation exposure group I and the highest lung and liver weight were also from inhalation exposure group I. The highest kidney weight was from inhalation exposure group III. The lowest Cd content in lung was 33.49㎍/g from inhalation exposure group I. The lowest Cd concentration in blood was 9.36㎍/㎗ from inhalation exposure control. Cd concentrations of 40.02㎍/g in liver and 69.18㎍/g in kidney were the lowest from inhalation exposure group I and III, respectively. The lowest Cd concentration in liver was 21.08㎍/g from inhalation exposure group III and The lowest Cd concentration in kidney was 15.78㎍/g from inhalation exposure group II. For weekly Cd concentration in urine, the value of the fourth week from inhalation exposure group III was the highest. For weekly Cd concentration in feces, the value of the first week from inhalation exposure group III was the highest. The highest metallothionein concentration in lung was 53.42 ㎍/g from inhalation exposure group III and the highest metallothionein concentration in liver was 188.18㎍/g from inhalation exposure group III. The highest metallothionein concentration in kidney was 143.92㎍/g from inhalation exposure group III. The highest Hct, Hb, and WBC values were from inhalation exposure group II and the highest RBC value was from inhalation exposure group III.

• 동의생리병리학회지
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• 제17권3호
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• pp.700-710
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• 2003

For the experiment of the effects between cadmium aerosol inhalation toxicity and ethyl acetate extracts of Folium Mori, 4 inhalation exposure groups of rat were exposed to cadmium aerosol in air by whole-body inhalation exposure for 6 hours/day, 5 days/week, and 4 weeks. Cadmium concentration in the air was 0.96㎎/㎥ and mass median diameter (MMD) was 2.48㎛ with 1.85 of geometric standard deviation(GSD). Intraperitoneal injections of ethyl acetate extracts of Folium Mori to inhalation exposure groups were performed for 4 weeks and the results were as follows: The highest body weight gain for 4 weeks and food intake per day were 159.29/4 weeks in treated group III and 18.45g/day in treated group I, respectively. The highest lung and liver weights were 1.31 g in treated group I and 9.42g in treated group III, respectively. The highest kidney weight was 2.21g from treated group I. The lowest cadmium content in lung was 86.39㎍/g from treated group III and the lowest cadmium concentration in blood was 2.72㎍/㎗ from treated group II. Cadmium concentrations of 22.09㎍/g in liver and 24.82㎍/g in kidney were the lowest from inhalation exposure group I and III, respectively. For weekly cadmium concentration in urine, the value of the fourth week from treated group III was the highest, 1.35㎍/㎖. For weekly cadmium concentration in feces, the values of the second and fourth week from treated group I were the highest, 1.11㎍/g. The highest metallothionein concentration in lung was 31.85㎍/g from treated group III and the highest metallothionein concentration in liver was 205.77㎍/g from treated group III. The highest metallothionein concentration in kidney was 206.55㎍/g from treated group III. The highest Hct and Hb values were 38.26% and 11.63g/㎗ from treated group III, respectively. The highest RBC and WBC values were 7.68×106/㎣ and 9.85×10³/㎣ from treated group I, respectively.