• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2905-2908
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• 2013

Fluorescent and colorimetric recognition properties of 2-(4-N-phenyl-3-thiosemicarbazone)-8-hydroxyquinoline (1) in buffered aqueous solution (1% DMSO, HEPES 20 mM, pH = 7.4) have been examined. Sensor 1 displays highly selective and sensitive recognition to $Cu^{2+}$ with fluorescence "ON-OFF" performance. The in situ formed 1-$Cu^{2+}$ complex exhibits an excellent selectivity toward sulfide ions with fluorescence "OFF-ON" behavior via $Cu^{2+}$ displacement approach. Thus, relay recognition of $Cu^{2+}$ and sulfide by a known molecule 1 has been achieved.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2256-2260
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• 2013

A new quinoline-based acylhydrazone (1) has been synthesized and applied as a fluorescent probe. Probe 1 exhibits high selectivity and sensitivity to $Cu^{2+}$ with fluorescence "ON-OFF" behavior in HEPES buffered (1‰ DMSO, HEPES 20 mM, pH = 7.4) solution. The on-site generated 1-$Cu^{2+}$ complex displays excellent selectivity to sulfide ions with fluorescence "OFF-ON" performance through copper displacement approach.

• 한국환경과학회지
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• 제25권11호
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• pp.1555-1562
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• 2016

Concentrations of hydrogen sulfide in ambient air have been measured from January 2014 to June 2016 in a coastal area near the Ulsan National Industrial Complex. The measurement sites were 1 km, 2.6 km, 5.6 km, and 20 km away from a kraft pulp mill, which is located at the most southern edge of the complex. Concentrations above 0.4 ppb were monitored every 5 min and the highest concentration of the day was determined. From a total of 775 measurement days, hydrogen sulfide concentrations > 20 ppb were recorded on 36 and 38 days at the measurement site closest to the mill and the residential area 2.6 km away from the mill, respectively. At the site farthest from the mill, the concentrations were always 20 ppb lower than the malodor regulation for the residential area but sometimes higher than the odor recognition threshold for hydrogen sulfide. Although several emission sources of hydrogen sulfide have been published in the Pollutant Release and Transfer Register of Korea, the kraft pulp mill is considered to be the biggest contributor of atmospheric hydrogen sulfide in the southern coastal area of Ulsan.

• 한국대기환경학회지
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• 제29권6호
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• pp.811-817
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• 2013

A two-stage bioreactor system using sulfur-oxidizing bacteria was studied to abate high strength hydrogen sulfide ($H_2S$) from biogas. The two-stage bioreactor consisted of a $H_2S$ absorption column (0.5 L) and a microbial oxidation column (1 L) in series, and the liquid medium was continuously recirculated through the columns. The objectives of this study were to determine the feasibility of the bioreactor for biogas desulfurization and to investigate the effect of the medium circulation rate on the system performance. An averaged concentration of $H_2S$ introduced to the bioreactor was 530 ppm, corresponding to an overall loading rate of $44.4g/m^3/hr$. During the initial 20 days period at the medium recirculation rate of 8 reactor volumes per hour (12 L/hr), the dissolved oxygen (DO) concentration in the oxidation column was 6 mg/L, while the DO in the absorption column was 0.5 mg/L showing that the oxygen contents of the biogas stream was not altered. Because of the biological oxidation of $H_2S$ in the oxidation column, the sulfate concentration increased from 200 mg/L to 5,600 mg/L in the liquid medium. The removal efficiency of $H_2S$ was greater than 99% in the initial operation period. After the initial period, the medium recirculation rate between the two columns was stepwise changed eight times from 1.0 to 40 vol/hr (1.5~60 L/hr). At the recirculation rate of faster than 4 vol/hr, the $H_2S$ removal efficiencies were found to be high, but the efficiency declined at the lower recirculation rates than the threshold.

• 한국치위생학회지
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• 제8권1호
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• pp.1-12
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• 2008

I investigated the situation of self-realization for oral malodor and real occurrence of it and researched the situation of coincidence by self-administrated questionnaire and real oral malodor of dental hygiene students in Kyeonggi province and Kyeongbuk province to use as a reference data on prevention and treatment of oral malodor. The obtained results were as follows: 1. Concerning the grade of the subjective symptom of oral odor, a little bit oral malodor was the highest by reaching 77.6%, and no oral malodor was 20%. 2. The time when one feels the oral malodor highest was revealed immediately after awakening from the sleep by running up to 88.2%. 3. Concerning the extent of aversion during the occurrence of oral malodor from other people, 57.6% expressed as unpleasant, and 3.5% showed no aversion. 4. Concerning the intention to participate in the prevention program against the oral malodor, 51.8% had intention of it. 5. Hydrogen sulfide 7.61V19.30, methyl mercaptan 9.53V67.90, dimethyl sulfide 58.31V121.37(pF0.05) marked as causing factors in the 132 respondents who answered that they had a little bit oral malodor in comparison with the grade of subjective symptom and the measurement of actual oral malodor. As the above-mentioned results were obtained by limited subjects, the more diversified and precise comparative study is considered to be needed through the classification of various levels of research subjects.

• 한국어병학회지
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• 제25권1호
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• pp.11-20
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• 2012

C-type lectins are crucial for pathogen recognition, innate immunity, and cell-cell interactions. In this study, a C-type lectin gene was cloned from the rock bream. The full-length RbCTL cDNA was 729 bp with a 429 bp ORF encoding a 164-residue protein. The deduced amino acid sequence of RbCTL had all of the conserved features crucial for its fundamental structure, including the four cysteine residues involved in sulfide bridge formation and potential $Ca^2+$/carbohydrate-binding sites. RbCTL contains a signal peptide one single carbohydrate recognition domain. It showed 29.4% similarity to the C-type lectin of rainbow trout. RbCTL mRNA was predominately expressed in gill and head-kidney tissue and expressed less in peripheral blood leukocytes, trunk-kidney, spleen, liver, intestine and muscle. Expression of RbCTL was differentially upregulated in rock bream stimulated with LPS, Con A/PMA and poly I:C.

• 한국어병학회지
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• 제27권2호
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• pp.99-105
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• 2014

Biosensors consist of biochemical recognition agents like antibodies immobilized on the surfaces of transducers that change the recognition into a measurable electronic signal. Here we report a piezoelectric immunosensor made to detect Vibrio vulnificus. A 9MHz AT-cut piezoelectric wafer attached with two gold electrodes of 5mm diameter was used as the transducer of the QCM biosensor with a reproducibility of ${\pm}0.1Hz$ in frequency response. We have tried different approaches to immobilize antibody on the sensor chip. Concerning the orientation of antibody for the best antigen binding capacity, the antibody was immobilized by specific binding to protein G or by cross-linking through hydrazine. In addition, protein G was cross-linked on glutaraldehyde activated immine layer (PEI) or EDC/NHS activated sulfide monolayer (MPA). PEI was found to be more effective to immobilize protein G following glutaraldehyde activation than MPA. However, hydrazine chip showed a better capability to immobilize more IgG than protein G chip and a higher sensitivity. The sensor system was able to detect V. vulnificus in dose dependent manner and was able to detect bacterial cells within 5 minutes by monitoring frequency shifts in real time. The detection limit can be improved by preincubation to enrich the bacterial cell number.

• 전자공학회논문지
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• 제49권9호
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• pp.314-321
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• 2012

축산생육환경에서 다양한 경로로부터 발생하는 유해가스는 가축 및 농가작업자에게 직/간접 적으로 영향을 미칠 수 있으며, 점차적인 사육조밀화와 동절기 밀폐환경에 장기간 노출 시 치명적일 수 있다. 본 논문에서는 가축분뇨로부터 발생하는 암모니아, 황화수소, 휘발성유기화합물 가스 등을 모니터링하기 위해 무선가스센서노드와 퍼지 최소-최대 신경회로망을 이용한 가스인식 소프트웨어로 이루어진 가스측정시스템을 제안한다. 제안한 시스템의 성능을 평가하기 위해 가스측정실험환경을 구축하여 제작한 무선가스센서노드로 가스측정실험을 수행하고, 개발한 가스인식 소프트웨어로 대상가스 분류시험을 통해 성능을 입증한다.

• 세라미스트
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• 제22권1호
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• pp.70-81
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• 2019

Breath analysis is rapidly evolving as a non-invasive disease recognition and diagnosis method. Metal oxide gas sensors are one of the most ideal platforms for realizing portable, hand-held breath analysis devices in the near future. This paper reviewed the recent developments in metal oxide gas sensors detecting exhaled biomarker gases such as nitric oxides, acetone, ammonia, hydrogen sulfide, and hydrocarbons. Emphasis was placed on strategies to tailor sensing materials/films capable of highly selective and sensitive detection of biomarker gases with negligible cross-response to ethanol, the major interfering breath gas. Specific examples were given to highlight the validity of the strategies, which include optimization of sensing temperature, doping additives, utilizing acid-base interaction, loading catalysts, and controlling gas reforming reaction. In addition, we briefly discussed the design and optimization method of gas sensor arrays for implementing the simultaneous assessment of multiple diseases. Breath analysis using high-performance metal oxide gas sensors/arrays will open new roads for point-of-care diagnosis of diseases such as asthma, diabetes, kidney dysfunction, halitosis, and lung cancer.