• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.110-117
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• 2021

Toxic megacolon is a fatal complication of inflammatory or infectious bowel disease. Prognosis depends on the severity of the disease. In cases of poor prognosis, clinical outcomes range from intestinal resection to death, so early diagnosis and appropriate treatment are very important. However, the prevalence of toxic megacolon in children is very low, and in those without underlying diseases such as inflammatory bowel disease, early diagnosis may be delayed. A previously healthy 12-year-old boy presented to our hospital with lower abdomen pain, fever, and hematochezia. Despite antibiotic therapy, the symptoms worsened. On the third day, abdominal computed tomography revealed severe dilatation of the transverse colon, which indicated toxic megacolon. Stool culture was positive for Salmonella enteritidis group D, and rectal endoscopy showed no signs of inflammatory bowel disease. Ceftriaxone and intravenous methylprednisolone were administered, and the patient's condition improved without any complications. We report a case of toxic megacolon as a complication of infectious colitis caused by S. enteritidis group D, which was diagnosed using early imaging and successfully treated without surgical intervention.

• Korean Journal of Hazardous Materials
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• v.2 no.1
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• pp.18-26
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• 2014

We analyzed the demand of competent authorities requiring adequate technical information for initial investigation of chemical accidents. Reflecting technical reports on chemical accident response by environmental agencies in the U.S. and Canada, we presented information on environmental diffusion and toxic effects available for the first chemical accident response. Hydrogen fluoride may have the risk potential to corrode metals and cause serious burns and eye damages. In case of inhalation or intake, it could have severe health effects. The substance itself is inflammable, but once heated, it decomposes producing corrosive and toxic fume. In case of contact with water, it can produce toxic, corrosive, flammable or explosive gases and its solution, a strong acid, may react fiercely with a base. In case of hydrogen fluoride leak, the preventive measures are to decrease steam generation in exposed sites, prevent the transfer of vapor cloud and promptly respond using inflammable substances including calcium carbonate, sodium bicarbonate, ground limestone, dried soil, dry sand, vermiculite, fly ash and powder cement. The method for fire fighting is to suppress fire with manless hose stanchions or monitor nozzles by wearing the whole body protective clothing equipped with over-pressure self-contained breathing apparatus from distance. In case of transport accident accompanied with fire, evacuation distance is 1,600m radius. In cae of fire, fire suppression needs to be performed using dry chemicals, CO₂, water spray, water fog, and alcohol-resistance foam, etc. The major symptoms by exposure route are dyspnoea, bronchitis, chemical pneumonia and pulmonary edema for respiration, skin laceration, dermatitis, burn, frostbite and erythema for eyes, and nausea, diarrhea, stomachache, and tissue destruction for digestive organs. In atmosphere, its persistency is low, and its bioaccumulation in aquatic organism is also low.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.22-27
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• 2019

Nail polish is used to decorate nail beautifully however, it contains lots of toxic materials. Generally, Nail polish consists of film-forming agent, colorant, solvent, surfactant and stabilizer. In this study, to replace toxic chemicals to low irritative, eco-friendly ingredients, we prepared 4 kinds of nail polish and tested safety, stability and performance. Nail polish including shellac/gelatin showed best performance in water-resistance, friability and drying time. When cell toxicity test is done by MTT assay, shellac-gelatin nail polish showed over 70% cell viability at $1,000{\mu}g/mL$ whereas control nail polish in market showed 50% cell viability. At 4 weeks temperature stability test, color was stable at low temperature however it needs formulation improvement at higher temperature.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.296-303
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• 2021

The objective of this study is to investigate the applicability of a Cu-supported honeycomb catalyst as a catalyst for decomposition of a low toxic liquid propellant based on ammonium dinitramide (ADN). A mixture of copper, lanthanum, and alumina was supported on the honeycomb support by wash coating to prepare a Cu-La-Al/honeycomb catalyst. We elucidated that the effect of metal loading on the physicochemical properties of Cu-La-Al/honeycomb catalyst and catalytic performance in decomposition of the ADN-based liquid propellant. As the number of wash coatings increased, the amount of active metal Cu was increased to 4.1 wt%. The BET surface area of the Cu-La-Al/honeycomb catalyst was in the range of 3.1~4.1 ㎡/g. The micropores were hardly present in Cu-La-Al/honeycomb catalysts, however, the mesopores and macropores were well developed. The Cu (2.7 wt%)-La-Al/honeycomb catalyst exhibited the highest activity in the decomposition of the ADN-based liquid propellant, which is attributed to the largest surface area, the largest pore volume, and the well-developed mesopores and macropores.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.199-199
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• 2003

During the cleanup of US Department of energy facilities, contaminated materials, toxic and hazardous radionuclides (e.g., Th, Cs, and U) and heavy metals (e.g., Cr, Hg, Pb, and Ni)-laden ultrafine particles are generated. The size of the particles is up to about 200 nm. Understanding of the production of these nanometer size particles is critical in determining the surface cleaning efficiently. (omitted)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.203-204
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• 2003

Ammonia in aquaculture system may lead to suppression of fish growth, sublethal histopathological changes, and even death thus ammonia is considered toxic to fish. Tricking filter and submerged filter have many advantages include: low construction cost, easy management and maintenance, and well adaptation to different water and waste loading rates. (omitted)

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.198.1-198.1
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• 2016

Organic light-emitting diode (OLED) displays have promising potential to replace liquid crystal displays (LCDs) due to their advantages of low power consumption, fast response time, broad viewing angle and flexibility. Organic light emitting materials are vulnerable to moisture and oxygen, so inorganic thin films are required for barrier substrates and encapsulations.[1-2]. In this work, the silicon-based inorganic thin films are deposited on plastic substrates by plasma-enhanced chemical vapor deposition (PECVD) at low temperature. It is necessary to deposit thin film at low temperature. Because the heat gives damage to flexible plastic substrates. As one of the transparent diffusion barrier materials, silicon oxides have been investigated. $SiO_x$ have less toxic, so it is one of the more widely examined materials as a diffusion barrier in addition to the dielectric materials in solid-state electronics [3-4]. The $SiO_x$ thin films are deposited by a PECVD process in low temperature below $100^{\circ}C$. Water vapor transmission rate (WVTR) was determined by a calcium resistance test, and the rate less than $10.^{-2}g/m^2{\cdot}day$ was achieved. And then, flexibility of the film was also evaluated.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.73-80
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• 2007

This study was carried out to separate the heavy toxic metals in eco-building materials by low-temperature pyrolysis, especially arsenic (As) compounds in CCA wood preservative as a solid in char. The pyrolysis was carried out to heat the CCA-treated Hemlock at $280^{\circ}C$, $300^{\circ}C$, $320^{\circ}C$, and $340^{\circ}C$ for 60 mins. Laboratory scale pyrolyzer composed of [preheater$\rightarrow$pyrolyzer$\rightarrow$1st water scrubber$\rightarrow$2nd bubbling flask with 1% $HNO_3$ solution$\rightarrow$vent], and was operated to absorb the volatile metal compound particulates at the primary water scrubber and the secondary nitric acid bubbling flask with cooling condenser of $4^{\circ}C$ under nitrogen stream of 20 mL/min flow rate. And the contents of copper, chromium and arsenic compounds in its pyrolysis such as carbonized CCA treated wood, 1st washing and 2nd washing liquors as well as its raw materials, were determined using ICP-AES. The results are as follows : 1. The yield of char in low-temperature pyrolysis reached about 50 percentage similar to the result of common pyrolytic process. 2. The higher the pyrolytic temperature was, the more the volatiles of CCA, and in particular, the arsenic compounds were to be further more volatile above $320^{\circ}C$, even though the more repetitive and sequential monitorings were necessary. 3. More than 85 percentage of CCA in CCA-treated wood was left in char in such low-temperature pyrolytic condition at $300^{\circ}C$. 4. Washing system for absorption of volatile CCA in this experiment required much more contacting time between volatile gases and water to prevent the loss of CCA compounds, especially the loss of arsenic compound. 5. Therefore, more complete recovery of CCA components in CCA-treated wood required the lower temperature than $320^{\circ}C$, and the longer contacting time of volatile gases and water needed the special washing and recovery system to separate the toxic and volatile arsenic compounds in vent gases.

• Journal of Korean Society on Water Environment
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• v.34 no.1
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• pp.77-83
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• 2018

This paper aims to evaluate the results of toxicity testing with Daphnia magna and Vibrio fischeri on wastewater samples which might be influenced by ion imbalance. The effluents from factories were found to be more toxic with high salinity levels than those from public wastewater treatment plant (WTP) and sewage treatment plant (SWP). Clion composition was highest in the effluent, in terms of percentage, which was followed by $Na^+$, $SO_4^{2-}$ and $Ca^{2+}$. $K^+$ and $Mg^{2+}$ ion was relatively low. The sensitivity of D. magna test results was higher than V. fischeri. Among samples which were proved by V. fischeri testing to be nontoxic, the composition ratio of each ion whether toxic samples or nontoxic samples which were decided by D. magna toxicity testing, were compared. $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ ion composition ratio showed high level in nontoxic samples whereas $SO_4^{2-}$ and $Cl^-$ ion composition ratio was high in toxic samples. Accordingly, $SO_4^{2-}$ and $Cl^-$ ion seemed to be considered the ions causing toxicity in effluent. Toxicity from some categories of industries (Mining of non-metallic minerals, Manufacture of basic organic petrochemicals, Manufacture of other basic organic chemicals, Manufacture of other chemical products etc.) seemed to be influenced by salinity. The Ion concentration in influent and effluent were similar. Concentration of $Na^+$, $Cl^-$, $K^+$, $Ca^{2+}$ ions were high in influent, however $Mg^{2+}$ and $SO_4^{2-}$ ions were high in effluent.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.435-444
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• 2003

In 1957, Schwarz and Foltz discovered that selenium (Se) was an essential trace mineral and nutritionists then started extensive studies to figure out the metabolic function of this element which has been called as toxic mineral. The discovery that glutathione peroxidase (GSH-Px) contained Se demonstrated a biochemical role for Se as an essential trace element. The major physiological function of Se containing GSH-Px is thought to maintain low levels of $H_2O_2$ and other hydroperoxides in the cell to prevent tissues from peroxidation damages. It is known that the GSH-Px activity is increased when animals were fed high dietary levels of Se. Chemical properties of Se have much in common with sulfur (S) therefore Se would follow the sulfur pathways in its metabolism in animal body. Two sources of Se are available for supplementation of Se in animal feed. Inorganic Se can also exist in selenide (-2), elemental (0), selenite (+4) and selenate (+6) oxidation state with other minerals. When sulfur in S containing amino acids is replaced by Se, organic Se can be made and named "eleno"prior to the name of S containing amino acid, i.e. selenomethionine. Selenium deficiency affects humans as well as animals and dysfunctions such as exudative diathesis, retained placenta, mastitis, liver necrosis, Keshan disease, numerous diseases and cancer. From several centuries ago, Se toxicity was recognized in various animal species and much of the current toxic Se levels has been established largely based upon the controlled toxicity studies used inorganic Se. Toxic effects of Se in animal result in reduced feed intake, growth retardation, ataxia, diarrhea, alopecia and sloughing of hooves. However, several experiments demonstrated that Se deficiencies or toxicities were varied by dietary Se levels and sources. Recent studies demonstrated that the incidence of colorectal and prostate cancer was reduced by approximately 50% when humans consumed 200 ${\mu}g$ of Se daily.