• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 Proceedings of the 17th Symposium on Plant Biology Environmental Stress and Photosynthesis
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• pp.68-82
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• 1999

CHilling tolereance of plants are closely correlated with the degree of fatty acid unsaturation of membrane lipids. We studied the effects of low-temperature photoinhibition on the photochemical efficiency of photosystem II in terms of fatty acid unsaturation of thylakoid membranes lipids isolated from chilling -sensitive plants and chilling -resistant ones. To directly test the chilling tolerance of photosynthetic machinery in relation to membrane lipids, we further compared wild type tobacco plants with that of transgenic tobacco plants, in which the sensitivity to chilling had been enhanced by genetic modification of fatty acid unsaturation of chloroplast membrane lipids. The transgenic tobacco plants were found to contain reduced levels of unsaturated membrane fatty acids after being transformed with cDNA for glycerol-3-phophate acyltransferase from squash. The functional integrity of photosystem II during and recovery of photosynthesis from low-temperature photoinhibition will be discussed in connection with the degree of fatty acid unsaturation of chlorophast membranes lipids.

• 설비공학논문집
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• 제7권4호
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• pp.600-610
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• 1995

When combustion gas is cooled down below the dew point of sulfuric acid vapor in the heat recovery systems, condensation occurs. Since the condensed sulfuric acid solution causes low-temperature corrosion in materials, it is important to measure the SOx dew point by electric measurement. In this study, two kinds of probes having electric gaps of 1mm or 2mm were used. and experiments were carried out by the parameters of sulfuric acid vapor and water vapor concentration. The changes of electric current caused by sulfuric acid condensed on the surface of probe according to the cooling rate and the probe head surface temperature were sudied. The opimum cooling rate was decreased with the increasing of water vaper concentration regardless of sulfuric acid concentration. The sensitivity of electric current is improved for the narrower gap(1mm) of ring electrodes, but it rarely affects the SOx dew point measuring of different probes according to the change of cooling rate.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.566-569
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• 1996

A sensitivity method has been developed for the detection and determination of niflmic acid(NA) in human urine. Samples were extracted with diethylether. Flunixin (FN) was added to the sample prior to extraction as an internal standard. Niflumic acid was converted to its methyl derivative and analyzed by capillary gas chromatography/negative chemical isonization mass spectrometry. Using selected ion monitoring (SIM), the levels of NA down to 5 pg/ml could be detected in 5 ml spiked urine sample. Calibration curve was linear over the range of 0.5 ppm-50 ppm. The recovery of niflumic acid from urine at 40 pg/ml was to be $91.7{\pm}3.8(n=3)$ and the coefficient of variation was 4.1%.

• 치과방사선
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• 제27권2호
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• pp.7-13
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• 1997

조직학적으로 유용성이 입증된 산탈회법을 이용한 인접면 비교적 초기 치아 우식의 병소를 형성하여 진단율을 조사하였다. 산 용액을 이용하여 20개 인접면 치아우식을 20개 소구치에 형성하였고, 37개 인접면 치아우식을 30개 대구치에 형성하였다. 건전한 소구치 20개, 대구치 30개를 포함하여 총 96개 치아를 4개씩 나누어 24개의 블록을 형성하였고, 각각 2개 블록의 교합면을 교합시켜서, 교익촬영을 하였다. 촬영 결과를 36명의 치과의사들이인접면 치아우식의 유무를 기록하고, 동시에 및 ROC 분석을 위한 5 개 범주의 판독 기준으로 판독하여 기록하였다. 인접면 치아우식증 유, 무만으로 판독한 결과 진단의 sensitivity는 0.71, specificity는 0.78 이였다. ROC 분석 한 결과의 곡선도표 아래부분의 평균 면적은 약 0.806 이였다. 치아우식증 유무만으로 진단한 결과는 특정한 sensitivity와 specificity 만을 나타내지만, ROC 분석 결과는 주관적 진단 기준과 구별되는 고유의 진단 능력을 표시하는 1-specificity(False Positive)의 변화에 따른 sensitivity(True Positive)의 변화를 연속적으로 나타내어 주었다.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1125-1131
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• 2006

A kan'::luxCDABE fusion strain that was both highly bioluminescent and responsive to benzoic acid was constructed by transforming E. coli strain W3110 with the plasmid pUCDK, which was constructed by digesting and removing the 7-kb KpnI fragment from the promoterless luxCDABE plasmid pUCD615. Experiments using buffered media showed that this induction was dependent on the pH of the media, which influences the degree of benzoic acid protonation, and the expression levels seen are likely due to acidification of the cytoplasm by uncoupling of benzoic acid. Consequently, the sensitivity of this strain for benzoic acid was increased by nearly 20-fold when the pH was shifted from 8.0 to 6.5. Benzoic acid derivatives and several phenolics also resulted in significantly increased bioluminescent signals. Although these compounds are known to damage membranes and induce the heat-shock response within E. coli, bacterial strains harboring mutations in the fadR and rpoH genes, which are responsible for fatty acid biosynthesis during membrane stress and induction of the heat-shock response, respectively, showed that these mutations had no effect on the responses observed.

• Asian Journal of Atmospheric Environment
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• 제4권1호
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• pp.55-61
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• 2010

The sensitivity of aerosol light extinction coefficient to the aerosol chemical composition change is estimated by (1) calculating the aerosol water content and chemical concentrations by a gas/particle equilibrium model and (2) calculating the aerosol light extinction coefficient by a Mie theory based optical model. The major chemical species are total (gas and particle phase) sulfuric acid, total nitric acid, and total ammonia which are based on the measurement data at Seoul and Gosan. At Seoul, since there were enough ammonia to neutralize both total sulfuric acid and total nitric acid, the dry ionic concentration is most sensitive to the variation of the total nitric acid level, while the total mass concentration (ionic concentration plus water content) and thus, the aerosol light extinction coefficient are primarily determined by the total sulfuric acid. At Gosan, since the concentration of ambient sulfuric acid was the highest among the inorganic species, sulfate salts determined aerosol hygroscopicity. Thus, both ionic and total mass concentration, and resultant aerosol light extinction coefficient are primarily determined by the sulfuric acid level.

• 한국지역사회생활과학회지
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• 제24권1호
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• pp.5-12
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• 2013

Caffeine is an alkaloid of the methylxanthine family known as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness in humans. There is a recommended upper limits of caffeine for health because a high dose can cause negative effects. Chlorogenic acid is a natural polyphenol compound known to have an antioxidant activity. In this study, the contents of caffeine and chlorogenic acid in coffee beans from different origins(Costa Rica, Indonesia, Vietnam) were determined by using liquid chromatography-tandem mass spectrometry(LC-MS/MS). The experiment offers more selectivity and sensitivity for those compounds compared with conventional methods such as UV/VIS spectrophotometry. The average concentrations of caffeine and chlorogenic acid in coffee beans origined in Costa Rica were 15.05 mg/g and 5.33 mg/g respectively. In the case of coffee beans origined in Indonesia, the average concentrations were 13.10 mg/g for caffeine and 3.75 mg/g for chlorogenic acid. Vietnamese coffee showed that the average concentrations were 17.79 mg/g for caffeine and 1.12 mg/g for chlorogenic acid. This study can contribute to a better understanding of the contents of caffeine and chlorogenic acid in various coffee beans in order to evaluate dietary intake.

• 공업화학
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• 제10권8호
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• pp.1169-1174
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• 1999

본 연구에서는 sodium 2-diazo-1-naphthoquinone-5-sulfonate를 chlorination하여 2-diazo-naphthoquinone-5-sulfonyl chloride(NQD-Cl)를 합성하였다. NQD-Cl을 여러 종류의 hydroxybenzophenone 유도체와 esterification하여 hydroxy group이 2-diazo-naphthoquinone-5-sulfonyl(NQD) group으로 치환된 여러 종류의 1,2-naphthoquinone-(1,2)-diazide-5-sulfonic acid esters(NQD0ester) 유도체를 합성하였다. NQD-ester 유도체의 용해도를 증가시키기 위해 methoxy group이 도입된 유도체와 이와 비교를 위해 hydroxy group만을 가지는 benzophenone 유도체를 사용하여 비교하였다. 각각의 NQD-ester 유도체의 용해특성을 조사하였으며, novolac수지와 혼용(formulation)하여 감광액을 제조하여 알루미늄판에 도포, 건조하여 PS판을 제조하였다. PS판의 감광특성과 광퇴색도와 화상형성에 적합한 노광시간을 조사하였으며, 상대감도를 gray scale(GS)법으로 조사하였다. 치환된 NQD group 의 수에 따라 GS법에 의한 상대감도가 다르게 나타나는 것을 알 수 있었다. Methoxy group이 도입된 NQD-ester유도체는 좋은 용해특성을 보여주었으며 시판되는 PS판과 동일한 노광조건에서 비교해 본 결과 보다 우수한 감도를 보였다.

• Childhood Kidney Diseases
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• 제22권2호
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• pp.47-51
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• 2018

Purpose: Urinary tract infection (UTI) is one of the common infectious diseases in children. Several imaging modalities can be used to confirm the presence of acute pyelonephritis (APN). Among them the 99mTcdimercaptosuccinic acid renal scan (DMSA scan) is used as a gold standard for diagnosis. Ultrasonography technology is evolving. Therefore, in this study, we investigated the sensitivity and specificity of Power Doppler ultrasonography (PDU) compared to the results from the previous study. Methods: There were 260 patients included in this study, aged between 1 and 12 months old. The patients were admitted to the Yeungnam University Medical Center between January 2008 and December 2015. All patients underwent both DMSA scan and PDU within 5days of admission. Voiding cystourethrography (VCUG) was performed in 195 patients with abnormal DMSA scan or PDU. Results: The diagnostic sensitivity of APN using PDU was 45.5% and specificity was 85.5% in 260 patients following detection of a defect on DMSA scan that was defined as APN. The diagnostic sensitivity and specificity of PDU for VUR were 65.5 % and 60.1%, respectively. The diagnostic sensitivity and specificity of DMSA scan for VUR were 95.7% and 14.1%, respectively. Conclusion: PDU has a high specificity but low sensitivity, so there are limitations in using it to replace a DMSA scan for the diagnosis of APN in children. DMSA scan and PDU have different sensitivity and specificity in diagnosis of VUR, respectively. Therefore, we suggest that the sensitivity and specificity of each test can be helpful in diagnosing APN and VUR when used in conjunction.

• Journal of Microbiology and Biotechnology
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• 제7권5호
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• pp.341-344
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• 1997

Batch cultures of Anacystis nidulans BD-1 resistant to azaleucine and fluorotyrosine produced and liberated a wide range of amino acids, notably glutamic acid, alanine, phenylalanine, leucine, isoleucine, cysteine and methionine. Sustained liberation for prolonged periods was achieved after immobilization on calcium alginate and the net concentration in the medium was 0.18-0.2 g $I^{-1}$. While acetohydroxy acid synthase in azaleucine-resistant mutant lost leucine- and isoleucine-sensitivity, fluorotyrosine-resistant strain turned phenylalanine activating. The activities of nitrate assimilating enzymes were also higher in the mutants and were relaxed from ammonium-repression. The metabolic adjustments involved in amino acid overproduction are discussed.