• 약학회지
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• 제54권4호
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• pp.226-231
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• 2010

Oral fluid has become increasingly popular as an alternative specimen in the field of driving under the influence of drugs (DUID) and work place drug testing. In this study, an analytical method for the detection and quantification of ${\Delta}^9$-tetrahydrocannabinol (THC) and its metabolite, 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THC-COOH) in oral fluid by SPE and GC-MS was established and fully validated. The stability of THC and THC-COOH in oral fluid during storage was also determined by examining the THC and THC-COOH concentration changes depending on time and container materials. Oral fluid samples were kept over 21 days at room temperature, $-4^{\circ}C$ and $-20^{\circ}C$ in two different specimen collection tubes; glass and polypropylene tubes. Three replicates for each condition with different temperature and types of a container were analyzed at five different time points over 21 days. When oral fluid samples were stored in glass tubes, the loss of both THC and THC-COOH was less than 10% at all room temperature, $-4^{\circ}C$ and $-20^{\circ}C$. However, in polypropylene tubes, the loss of both THC and THC-COOH increased significantly over the study period. In particular, the concentration of THC decreased more rapidly than that of THC-COOH at room temperature and the maximal percentage of THC lost was 90.3% after 21 days. The result indicates that it would be necessary to collect oral fluid samples in glass containers and cool the samples until analysis in order to prevent the degradation of analytes.

• Biomolecules & Therapeutics
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• 제21권1호
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• pp.60-65
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• 2013

3,4,5-Trihydroxycinnamic acid (THC) is a derivative of hydroxycinnamic acids, which have been reported to possess a variety of biological properties such as anti-inflammatory, anti-tumor, and neuroprotective activities. However, biological activity of THC has not been extensively examined. Recently, we reported that THC possesses anti-inflammatory activity in LPS-stimulated BV2 microglial cells. However, its precise mechanism by which THC exerts anti-inflammatory action has not been clearly identified. Therefore, the present study was carried out to understand the anti-inflammatory mechanism of THC in BV2 microglial cells. THC effectively suppressed the LPS-induced induction of pro-inflammatory mediators such as NO, TNF-${\alpha}$, and IL-$1{\beta}$. THC also suppressed expression of MCP-1, which plays a key role in the migration of activated microglia. To understand the underlying mechanism by which THC exerts these anti-inflammatory properties, involvement of Nrf2, which is a cytoprotective transcription factor, was examined. THC resulted in increased phosphorylation of Nrf2 with consequent expression of HO-1 in a concentration-dependent manner. THC-induced phosphorylation of Nrf2 was blocked with SB203580, a p38 MAPK inhibitor, indicating that p38 MAPK is the responsible kinase for the phosphorylation of Nrf2. Taken together, the present study for the first time demonstrates that THC exerts anti-inflammatory properties through the activation of Nrf2 in BV2 microglial cells, suggesting that THC might be a valuable therapeutic adjuvant for the treatment of inflammation-related disorders in the CNS.

• 한국환경과학회지
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• 제25권8호
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• pp.1177-1189
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• 2016

In order to prepare the information needed to construct a reduction system for volatile organic compounds (VOCs) exhausted from ship-block paint-booths in a giant shipyard, VOCs in paint-shop airs were analyzed and compared to the components in paint thinners. Aromatic hydrocarbons containing eight and nine carbon atoms are known to be major VOC compounds found in shipyard paint-shops. The total hydrocarbon (THC(C7)) concentrations calibrated using toluene gas, were measured in block paint-shops with two photo-ionization detector (PID) meters, and the resulting THC(C7) data were converted to THC(C1) concentrations according to the Standard Methods for the Measurements of Air Pollution in South Korea. THC(C1) concentrations near the spray site ranged from 10 to 2,000 ppm, but they were less than 400 ppm near the walls of the paint-booth. The measurements of THC concentrations, based on the height of the monitoring sites, were related to the height of the target to which the spray paints were applied. The maximum concentrations occurred at almost the same height as the spray targets. When painted blocks had been dried-by warming with no spraying, the THC concentrations were 80~100 ppm.

• 청정기술
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• 제27권1호
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• pp.79-84
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• 2021

본 연구에서는 도장 공정에서 사용된 폐활성탄을 원통형 카트리지에 충진하여 저온 가스에 의한 탈착 특성을 파악하였다. 폐활성탄의 탈착유량을 결정하기 위하여 활성탄의 톨루엔 흡착 및 탈착 실험을 진행하였다. 실험결과에서 1, 2, 4 ㎥ min-1의 유량으로 탈착을 하였을 때 높은 THC 농도와 탈착시간에 의하여 2 ㎥ min-1이 적절하다고 판단하였다. 폐활성탄은 탈착시간 초기에 가스성분에서 비점이 낮은 2-butanone과 MIBK (methyl isobutyl ketone)가 높은 비율로 발생되었고, 그 이후에는 THC의 농도가 감소하면서 BTX계열이 상대적으로 높은 비율로 탈착되었다. 폐활성탄의 탈착시간 동안 발생되는 가스 성분의 총 열량은 316 kcal kg-1으로 나타났다. 폐활성탄을 이용하여 톨루엔으로 5회 반복 재생한 결과에서는 요오드가 및 비표면적이 신탄에 비하여 상대적으로 낮은 것으로 분석되었다. 원통형 카트리지 2개를 직렬로 연결한 탈착실험에서는 최대 THC농도가 약 470 ppm으로 나타났다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.516-521
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• 2004

In this paper, the effects of ethanol blended gasoline on emissions and their catalytic conversion efficiencies characteristics were investigated in gasoline engine with an electronic fuel injection. The results showed that the increase of ethanol concentration in the blended fuels brought the reduction of THC and $CO_2$ emissions from the gasoline engine. THC emissions were drastically reduced up to thirty percent. And brake specific fuel consumption was increased. but brake specific energy consumption was similar level. However. unburned ethanol and acetaldehyde emissions increased. The conversion efficiency of Pt/Rh based three-way catalysts and the effect of ethanol on CO and NOx emissions were investigated by the change of engine speed. load and air/fuel ratio. Furthermore, the ethanol blended fuel results in the reduction effect of THC. CO and NOx emissions at idle speed.

• 대한기계학회논문집
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• 제8권3호
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• pp.210-216
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• 1984

본 연구에서는 이러한 화염의 구조를 자세히 파악하기 위하여, 화염의 온도분 포 및 가스농도분포 등을 비교적 정밀하게 측정하고 Shadow graph 등을 통하여, 선회 화염의 거시적인 구조적 특성을 알아보고 일산화질소, 탄화수소 및 일산화탄소 등의 생성특성을 규명함으로서 실제 버어너에서의 기하학적 변형에 따른 화염구조의 예측과 수치해석을 위한 기본 데이타를 얻고, 공해물질발생과 화염구조와의 상관관계를 제시 하는데 그 목적이 있다.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.407-413
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• 2006

The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1127-1130
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• 2003

In the last several centuries, humankind have been experienced the material abundance with a development of technical civilization and being industrialized quickly. During the process of this, environmental pollutant have occurred naturally so that humankind have more interests for environment pollutant. Air pollution caused by exhaust from a car is very harmful for human. Most of exhaust from a gasoline engine are $CO_x(CO+CO_2),\;NO_x(NO+NO_2)$, and THC(Total Hydrocarbon). The method to remove these kinds of noxious gases are so many thing such as the three catalysts, $NO_x$ catalysts, Filter and so on. However, although air pollution caused by exhaust from motorcycle have also occurred very much, there is no regulation for motorcycle. In this paper, we studied to remove $CO_x(CO+CO_2),\;NO_x(NO+NO_2)$, THC exhaust from a motorcycle using non-thermal plasma In the result, $NO_x(NO+NO_2)$ concentration was decreased approximately 70% and THC(Total Hydrocarbon) was removed about 40%.

• 분석과학
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• 제21권3호
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• pp.159-166
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• 2008

본 연구에서는 water/oil 유화연료를 제조하여 제조된 연료의 점도, 밀도, 최적의 조사시간, 유화 안정성 등의 유화연료 특성 및 배기배출물 특성인 NOx, THC, CO의 농도와 smoke density를 측정하였다. 유화연료는 경유, 물, 유화제를 첨가한 후 homogenizer와 초음파 발생장치를 일정시간 조사하여 제조하였고, 배출가스 시험은 2476 cc diesel engine을 사용하여 engine dinamo meter로 실험하였다. 유화연료에서 함수율이 증가할수록 밀도가 증가하였으며, 점도는 함수율 60%까지는 W/O type이 형성되어 증가하다가 70%에서는 O/W type이 형성되어 감소하였다. 배출가스 시험결과 함수율이 증가할수록 NOx 농도와 smoke density는 감소하고, THC와 CO 농도는 증가하였다. 출력감소 시험 결과 함수율이 증가할수록 배출온도와 출력이 감소하였다. 위의 결과로부터 압축착화 디젤기관에 유화연료를 사용하는 것은 NOx와 smoke를 제거하는 효과적인 방법이라고 사료되어진다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2007년도 Proceedings of The Convention
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• pp.57-64
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• 2007

Metabolic interactions of the three major cannabinoids, ${\Delta}^9$-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) with steroid hormones were investigated. These cannabioids concentration-dependently inhibited $3{\beta}$-hydroxysteroid dehydrogenase and $17{\alpha}$-hydroxylase in rat adrenal and testis microsomes. CBD and CBN were the most potent inhibitors of $3{\beta}$-phydroxysteroid dehydrogenase and progesterone $17{\alpha}$-hydroxylase, respectively, in rat testis microsomes. Three cannabinoids highly attenuated hCG-stimulated testosterone production in rat testicular interstitial cells. These cannabinoids also decreased in levels of mRNA and protein of StAR in the rat testis cells. These results indicate that the cannabinoids could interact with steroid hormones, and exert their modulatory effects on endocrine and testicular functions. Metabolic interaction of a THC metabolite, $7{\beta}$-hydroxy-${\Delta}^8$-THC with steroids is also investigated. Monkey liver microsomes catalyzed the stereoselective oxidation of $7{\beta}$-hydroxy-${\Delta}^8$-THC to 7-oxo-${\Delta}^8$-THC, so-called microsomal alcohol oxygenase (MALCO). The reaction is catalyzed by CYP3A8 in the monkey liver microsomes, and required NADH as well as NADPH as an efficient cofactor, and its activity is stimulated by some steroids such as testosterone and progesterone. Kinetic analyses revealed that MALCO-catalyze reaction showed positive cooperativity. In order to explain the metabolic interaction between the cannabinoid metabolite and testosterone, we propose a novel kinetic model involving at least three binding sites for mechanism of the metabolic interactions.