• Applied Biological Chemistry
• /
• 제12권
• /
• pp.57-67
• /
• 1969

1. Furyl furamide 가 여름철 김치세균에 미치는 영향을 보기 위하여 두가지 여름김치에서 분리(分離)한 세균 Bacillus group 과 Lactic acid bacteria중 Bac. megaterium, Bac. subtilis 그리고 Bac. licheniformis등이 발효 초기(初期)의 젓갈김치에 우세 하였고 국물김치에서는 Lact. plantarum 과 Lact. buhneri등이 시종(始終) 매우 우세하였다. 2. 김치에서 분리(分離)된 Bacillus group 은 10 p.p.m. 이하(以下)의 AF-2 저농도(低濃度)에서 대단히 민감(敏感)하게 억제되었으나 Lactic acid bacteria의 group은 50 p.p.m.의 고농도(高濃度)에서도 저항(抵抗)하고 있었다. 3. 김치의 AF-2 첨가허용농도(添加許容濃度)는 최고(最高) 10 p.p.m.을 넘지 않아야 할 것이다. 4. 김치에 첨가(添加)된 고농도(高濃度)(50 p.p.m.)의 AF-2는 김치 발효를 heterofermentation 에서 Homofermentation으로 변화(變化)시키는 경향이 있었다. 5. AF-2 10 p.p.m. 농도(濃度)의 김치에서 bacterial flora는 약간 영향(影響)을 받고 있었으나, 50 p.p.m.의 고농도(高濃度)에서도 하절(夏節)김치의 산패(酸敗)는 억제할수가 없었다. 6. $23^{\circ}{\sim}25^{\circ}C$ 상태의 김치발효액중(醱酵液中)의 AF-2 소장(消長)은 산성(酸性)에서 비교적(比較的) 안전(安全)하다고 하나 4 일후(日後)에 약(約) 25%가 감소(減少)되고 pH 변화곡선(變化曲線)과 거의 평행(平行)한 변화(變化)를 보였다.

• 한국농림기상학회지
• /
• 제3권2호
• /
• pp.114-120
• /
• 2001

대기오염 농도가 높은 종로, 잠실, 그리고 남산지역과 대조구로 태능지역의 가로수로 식재된 은행나무 (Ginkgo biloba L)를 대상으로 대기오염에 노출되었을 때의 생육상황을 조사한 결과는 다음과 같다. 1. 서울에서 생육하고 있는 가로수 은행나무의 대기오염에 의한 엽록소 함량은 태능 48.77, 남산 47.90, 종로 46.88, 그리고 잠실 40.92로 태능지역이 가장 높게 나타났다. 각 지역별 흉고직경은 남산 23.8 cm, 종로 23.4cm, 태능 23.3cm,잠실 21.6cm로 조사지역간 흉고직경의 차이는 잠실지역 이외에는 별로 없다. 2. 대조구인 태능지역 보다 조사된 남산과 종로지역의 은행나무 엽록소 함량이 낮았다. 3. 잠실지역의 낮은 흉고직경은 도심지 가로수의 생육상황이 대기오염물질보다는 다른 외부인자에 의해서 영향 받을 수 있음을 나타낸다. 4. 분석에 사용된 Got-2, Pgi-2, Pgm, Acon, Mnr, Mdh, Skdh,및 6Pgd의 8개 동위효소에서 정색반응이 확인되었으며, 8개의 유전자좌 중 Pgi-2와 Mdh가 대립유전자에선 Pgi-2와 Pgm에서 각각 통계적인 유의성(P＜0.01)이 인정되었다. 5. T(tolerant), S(sensitive) 두 group으로 나누어 분석된 동위효소분석은 유전자당 대립유전자수(A/L)는 T가 2.63, S가 2.5로 나타났다.

• 해양환경안전학회지
• /
• 제15권1호
• /
• pp.11-15
• /
• 2009

이산화탄소($CO_2$) 해양격리처리 방안의 실효성을 검토하기 위해서는 해양에 처리된 $CO_2$가 해양생태계 및 해양생물에 미칠 수 있는 영향에 대해서 광범위하게 정보를 축적할 필요가 있다. 본 연구에서는 두족류인 참문어 Octopus vulgaris를 대상으로 고농도 $CO_2$ 환경(1, 2, 3%-$CO_2$)에서의 폐사율 및 1%-$CO_2$ 환경에서의 생리학적 반응에 대해서 조사하였다. 참문어는 혈액채취를 위하여 복부대동맥에 케뉴레이션을 행한 후 호흡실에서 회복시켰다. 회복된 개체에 대하여 헤모림프의 산염기 조절인자에 대한 측정을 행하였다. 참문어는 3%-$CO_2$ 환경에서 72시간 안에 100% 폐사하였다. 헤모림프의 pH는 1%-$CO_2$ 노출 30분 후 유의하게 감소하였으나 실험종료 때까지 회복되지 않았으며, $[HCO_3^-]$는 $CO_2$ 노출 후 유의하게 증가하여 8시간에 7.8 mM를 나타내었으나 그 후 점차 감소하는 경향이었다. 헤모림프 이온$([Cl^-],\;[Na^+],\;[K^+])$들은 유의한 변화를 보이지 않았다. 본 연구 결과 참문어는 방어, 넙치와 같은 경골어류 및 별상어와 같은 판새류보다 $CO_2$에 민감한 것으로 사료된다.

• Bulletin of the Korean Chemical Society
• /
• 제27권5호
• /
• pp.672-678
• /
• 2006

A new approach to fabricate an enzyme electrode was described based on the immobilization of horseradish peroxidase (HRP) on dithiobis-N-succinimidyl propionate (DTSP) self-assembled monolayer (SAM) formed on gold-nanoparticles (Au-NPs) which were electrochemically deposited onto glassy carbon electrode (GCE) surface. The overall surface area and average size of Au-NPs could be controlled by varying deposition time and were examined by Field Emission-Scanning Electron Microscope (FE-SEM). The $O_2$ reduction capability of the surface demonstrated that Au-NPs were thermodynamically stable enough to stay on GCE surface. The immobilized HRP electrode based on Au-NPs/GCE presented faster, more stable and sensitive amperometric response in the reduction of hydrogen peroxide than a HRP immobilized on DTSP/gold plate electrode not containing Au-NPs. The effects of operating potential, mediator concentration, and pH of buffer electrolyte solution on the performance of the HRP biosensor were investigated. In the optimized experimental conditions, the HRP immobilized GCE incorporating smaller-sized Au-NPs showed higher electrocatalytic activity due to the high surface area to volume ratio of Au-NPs in the biosensor. The HRP electrode showed a linear response to $H_2O_2$ in the concentration range of 1.4 $\mu$M-3.1 mM. The apparent Michaelis-Menten constant ($K _M\; ^{app}$) determined for the immobilized HRP electrodes showed a trend to be decreased by decreasing size of Au-NPs electrodeposited onto GCE.

• The Korean Journal of Ceramics
• /
• 제3권2호
• /
• pp.116-123
• /
• 1997

A chemically stabilized $\beta$-cristobalite, which is stabilized by stuffing cations of $Ca^{2+}$ and $Al^{3+}$, was prepared by a solution-polymerization route employing Pechini resin or PVA solution as a polymeric carrier. The polymeric carrier affected the crystallization temperature, morphology of calicined powder, and particle size distribution. In case of the polyvinyl alcohol (PVA) solution process, a fine $\beta$-cristobalite powder with a narrow particle size distribution (average particle size : 0.3$\mu\textrm{m}$) and a BET specific surface area of 72 $\m^2$/g was prepared by an attrition-milling for 1 h after calcination at 110$0^{\circ}C$ for 1h. Wider particle size distribution and higher specific surface area were observed for the $\beta$-cristobalite powder derived from Pechini resin. The cubie(P1-to-tetraganalb) phase transformation in polynystalline $\beta$-cristobalite was induced at approximately 18$0^{\circ}C$. Like other materials showing transformation toughening, a critical size effect controlled the $\beta$-to-$\alpha$ transformation. Densifed cristobalite sample had some cracks in its internal texture after annealing. The cracks, occurred spontaneoulsy on cooling, were observed in the sample with an average grain sizes of 4.0 $\mu\textrm{m}$ or above. In case of the sintered cristobalite having a composition of CaO.$2Al_2O_3$.40SiO$_2$, small amount of amorphous phase and slow grain growth during annealing were observed. Shear stress-induced transformation was also observed in ground specimen. Cristobalite having a composition of CaO.2Al2O3.80SiO2 showed a more sensitive response to shear stress than the CaO.$2Al_2O_3$.40SiO$_2$ type cristobalite. Shear-induced transformation resulted in an increase of volume about 13% in $\alpha$-cristobalite phase on annealing for above 10 h in the case of the former composition.

• 한국축산식품학회지
• /
• 제34권1호
• /
• pp.106-114
• /
• 2014

Folic acid, one of the B group of vitamins, is an essential substance for maintaining the functions of the nervous system, and is also known to decrease the level of homocysteine in plasma. Homocysteine influences the lowering of the cognitive function in humans, and especially in elderly people. In order to determine the strains with a strong capacity to produce folic acid, 190 bacteria were isolated from various kinds of jeotgal and chungkuk-jang. In our test experiment, JA71 was found to contain $9.03{\mu}g/mL$ of folic acid after 24 h of incubation in an MRS broth. This showed that JA71 has the highest folic acid production ability compared to the other lactic acid bacteria that were isolated. JA71 was identified as Lactobacillus plantarum by the result of API carbohydrate fermentation pattern and 16s rDNA sequence. JA71 was investigated for its physiological characteristics. The optimum growth temperature of JA71 was $37^{\circ}C$, and the cultures took 12 h to reach pH 4.4. JA71 proved more sensitive to bacitracin when compared with fifteen different antibiotics, and showed most resistance to neomycin and vancomycin. Moreover, it was comparatively tolerant of bile juice and acid, and displayed resistance to Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus with restraint rates of 60.4%, 96.7%, and 76.2%, respectively. These results demonstrate that JA71 could be an excellent strain for application to functional products.

• 대한의용생체공학회:의공학회지
• /
• 제38권2호
• /
• pp.57-61
• /
• 2017

The purpose of this study was to investigate the effect of direction (pitch and roll) on the perception of support surface rotation while standing. Thirty young healthy subjects participated in this study. Support surface was rotated at an unexpected instant in a very slow speed (0.2 deg/s). The direction of support surface rotation was randomly chosen among pitch (forward and backward) and roll (right and left) directions. The experiment was performed with eyes open and closed. Perception performance was evaluated by the perception threshold, defined as the rotation angle of the surface at the instant when a subject recognized that the support surface was moving. Results showed that the perception threshold was smaller for roll directions than pitch directions irrespective of vision and gender (p < 0.01). This indicates that the perception of support surface rotation is more sensitive in roll direction than in pitch direction. Among three sensory functions related to postural perception, the effect of vestibular and visual functions on the direction difference of the perception should be little because of the very slow surface rotation and independence on visual conditions. Therefore, the direction dependence of perception would have been affected mainly by the somatosensory function.

• 전자공학회논문지A
• /
• 제32A권1호
• /
• pp.152-158
• /
• 1995

Eteching characteristics of the Indium Tin Oxide (ITO), which is transparent conductor, was investigated with CH4/H2 and Ar as etching gases for the Reactive Ion Etching (RIE). With CH4/H2 for the etching gas, the highly selective etching characteristics for the ITO on GaAs was obtained. It was examined that the dominant etching parameter for the selective etchning of ITO on GaAs structure was the chamber pressure. But, the etching selectivity for ITO on InP was poor eventhough we tried systematic etching. RIE etching conditins using CH4/H2 gas was limited due to the formation of polymer on the substrates. In the case of Ar gas for the reactive gas, the selectivity of ITO on BaTiO3 was above 10. The etch rete of ITO was more sensitive to the etching parameters than that of BaTiO3, which was almost constant with different etching parameters.

• 말소리와 음성과학
• /
• 제6권3호
• /
• pp.63-72
• /
• 2014

The current study assessed the utility of acoustic analyses the most commonly used in routine clinical voice assessment including perturbation, nonlinear dynamic analysis, and Spectral/Cepstrum analysis based on signal typing of dysphonic voices and investigated their applicability of clinical acoustic analysis methods. A total of 70 dysphonic voice samples were classified with signal typing using narrowband spectrogram. Traditional parameters of %jitter, %shimmer, and signal-to-noise ratio were calculated for the signals using TF32 and correlation dimension(D2) of nonlinear dynamic parameter and spectral/cepstral measures including mean CPP, CPP_sd, CPPf0, CPPf0_sd, L/H ratio, and L/H ratio_sd were also calculated with ADSV(Analysis of Dysphonia in Speech and VoiceTM). Auditory perceptual analysis was performed by two blinded speech-language pathologists with GRBAS. The results showed that nearly periodic Type 1 signals were all functional dysphonia and Type 4 signals were comprised of neurogenic and organic voice disorders. Only Type 1 voice signals were reliable for perturbation analysis in this study. Significant signal typing-related differences were found in all acoustic and auditory-perceptual measures. SNR, CPP, L/H ratio values for Type 4 were significantly lower than those of other voice signals and significant higher %jitter, %shimmer were observed in Type 4 voice signals(p<.001). Additionally, with increase of signal type, D2 values significantly increased and more complex and nonlinear patterns were represented. Nevertheless, voice signals with highly noise component associated with breathiness were not able to obtain D2. In particular, CPP, was highly sensitive with voice quality 'G', 'R', 'B' than any other acoustic measures. Thus, Spectral and cepstral analyses may be applied for more severe dysphonic voices such as Type 4 signals and CPP can be more accurate and predictive acoustic marker in measuring voice quality and severity in dysphonia.

• Membrane and Water Treatment
• /
• 제9권4호
• /
• pp.211-220
• /
• 2018

Incorporating nano-materials in thin-film composite (TFC) membranes has been considered to be an approach to achieve higher membrane performance in various water treatment processes. This study investigated the rejection efficiency of three target compounds, i.e., reserpine, norfloxacin and tetracycline hydrochloride, by TFC membranes with different graphene oxide proportions. Graphene oxide (GO) was incorporated into the polyamide active layer of a TFC membrane via an interfacial polymerization (IP) reaction. The TFC membranes were characterized with FTIR, FE-SEM, AFM; in addition, the water contact angle measurements as well as the permeation and separation performance were evaluated. The prepared GO-TFC membranes exhibited a much higher flux ($3.11{\pm}0.04L/m2{\cdot}h{\cdot}bar$) than the pristine TFC membranes ($2.12{\pm}0.05L/m2{\cdot}h{\cdot}bar$) without sacrificing their foulant rejection abilities. At the same time, the GO-modified membrane appeared to be less sensitive to pH changes than the pure TFC membrane. A significant improvement in the anti-fouling property of the membrane was observed, which was ascribed to the favorable change in the membrane's hydrophilicity, surface morphology and surface charge through the addition of an appropriate amount of GO. This study predominantly improved the understanding of the different PA/GO membranes and outlined improved industrial applications of such membranes in the future.