• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.532-536
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• 2010

A study on the volatile organic compounds (VOCs) and low molecular weight (LMW) amount which is contained within bisphenol A polycarbonate (PC) was performed by the solvent extraction with ketone type solvents (acetone, butanone, pentanone). The LMW amount of untreated PC was 2.6 wt%, but the values of treated samples with acetone and pentanone were 0.96 and 1.53 wt%, respectively. Acetone is a more effective solvent than pentanone on the LMW extraction. Methylene chloride (MC) and toluene were certified and quantified by GC-Mass experiments, and the quantitative results indicated the fact that the pentanone was the effective solvent on VOC extraction. Focused on the change of VOCs and LMW amount, the use of co-solvent might be more useful, and the experimental results of co-solvent extraction showed that the optimum condition was 50 : 50 volume percent.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.312-316
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• 2000

Crude xylooligosaccharides(XO) were separated with a cellulose membrane (10,000 molecular weight cut-off). Flux variation was measured at transmembrane pressures of 5, 10, 20 and 30 psi, while flow rates were maintained at 100, 200, 300 and 400 ml/min and temperatures at 10, 20, 23-25 and $30^{\circ}C$. Optimal conditions were found at the transmembrane pressure of 20 psi, the flow rate of 300 ml/min and the temperature of $23-25^{\circ}C$, where the flux was decreasing with time by 62% after 200 min. Total sugar, total solid and ash contents were rather independent of ultrafiltration but protein was removed up to 55% from crude XO. Especially, the use of ultrafiltration was very effective for decolorization (84%) of crude XO. These results suggest that ultrafiltration is a useful method for the primary purification of XO.

• Journal of Conservation Science
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• v.26 no.3
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• pp.325-334
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• 2010

In order to clarify the effect of consolidant, the artificial porous material with low intensity was manufactured using granite powder and Portland cement. We have prepared four kinds of alkoxysilane system consolidants, a acrylic resin and a epoxy resin and investigated about characteristics before and after consolidation. As a result of the research, Silres BS OH 100 was effective for density and surface hardness. SS-101 with hydrophobicity and Site SX-RO with hydrophilicity had the good durability over salts weathering. On the other hand, Syton HT-50 and Paraloid B72 were easily destructed by salt weathering because they were concentrated on surface area by the low penetration depth. Araldite 2020 was the most effective consolidant for improvement of physical properties.

• Journal of Animal Environmental Science
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• v.9 no.2
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• pp.79-84
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• 2003

1.퇴비 온도의 상승에 비례하여 폐사계 체내의 온도도 상승하여 퇴적식 퇴비단의 경우 $55^{\circ}C$내외의 고온지속기간이 약 30일정도 유지되었다. 반면에 토양 중에 매립된 폐사계의 체내 온도는 발효 전 기간 동안 $30^{\circ}C$ 이상으로 상승하지 못한 채 주변토양 온도와 거의 비슷한 수준을 유지하였다. 토양온도는 외기온의 변화에 즉각적인 반응을 보이지 않았다. 2. 시험용 발효조 내에서의 송풍여부에 따른 퇴비의 발효온도 변화추이는 송풍 처리구에서는 퇴비화 3일째에 최고온도 $68^{\circ}C$를 기록한 반면에 무송풍구에서는 퇴비화 5일째에 최고온도 $72^{\circ}C$를 기록하였다. 3. 퇴비단 표층에서 채취된 시료에서 검출된 $H_2S$와 $CH_3$SH 농도는 송풍 처리구에 있어서는 퇴비화 개시 후 20일 경과 후 각 각 28.5, 16.0 ppb 수준을 나타냈고 35일 경과 시에는 각각 57.7, 11.7 ppb, $CH_3SH$의 경우에는 23.7, 9.9 ppb 수준의 발생량을 기록하는 등 전반적으로 송풍처리구가 무송풍 처리구에 비해 악취가스의 발생량이 상대적으로 낮았다. 4. 폐사계를 밀폐용기 내에서 발표 시 수거된 침출수 중의 미생물 수가 토양매립 상태 하에서 수거된 침출수 중의 미생물 수보다 더 적은 경향을 보이고 있다. 5. 퇴비단 내에서 발효에 따른 폐사계 중량은 최초 3일간에 급격히 감소하고 시간의 경과에 따라 그 감소속도는 줄어든다. 발효온도가 높을수록 조직의 분해속도가 빨라지고 폐사계의 중량감소 속도도 빨라졌다. 6. 일반 퇴비와 폐사계를 발효시킨 퇴비 사이에 비료성분과 중금속 함량의 유의적인 차이는 발견되지 않았다.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.127-132
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• 1994

Removal of viscous materials, mainly alginate, from sea tangle extracts by $CaCl_2$ precipitation or ultrafiltration was investigated. The sea tangle extracts were prepared by enzymatic hydrolysis of polysaccharides followed by 2 hours of boiling in 1.5% NaCl or 2.0% sucrose solution. The $CaCl_2$ precipitation resulted in higher amount of total solid, amino-nitrogen and mannitol than those values of ultrafiltration, but protein extracted was less in the former. Both methods caused a significant decrease in the viscosity and turbidity of the extracts. The composition of four nucleotides showed that UMP and IMP were not detected in $CaCl_2$ precipitated extracts, while ultrafiltered extracts showed a fairly even distribution of them. Removal of viscous material, particularly ultrafiltration increased the glutamic acid in amino acid composition and reduced serine, histidine, lysine, glycine, phenylalanine and leucine.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.89-95
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• 2002

In woody plant germplasms, using prefrozen dormant buds for materials is one way to achieve successful cryopreservation. The protocol of cryopreservation for White birch (Betula platyphylla var. japonica) winter vegetative buds is the following. First, the branches of White birch were collected in January 20, when the vegetative buds were still in a state of quiescence. The winter buds with about 5㎜ of xylem tissue were removed from the branches. They were dehydrated to moisture contents about 44% by air dry treatment. The buds were prefrozen, with the temperature being decreased by 5∼-20$\^{C}$ and then transfered to the LN(liquid nitrogen) maintained below -l96$\^{C}$. After cryopreservation, the vegetative buds were rapidly thawed in a water bath at 40$\pm$5$\^{C}$. In this case, the cell survival rate of samples was about 86%. After sterilization, buds were then cultured on MS medium. These results demonstrate the feasibility for cryopreservation of winter vegetation buds of Betula platyphylla var. japonica.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.175-175
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• 2013

현재 치과에서 상용되는 치아미백법은 과산화수소와 레이저를 사용하여 의사가 직접 치료를 하고 있다 [1]. 단기간에 높은 미백효과를 얻기 위해, 고농도의 과산화수소를 이용하게 되는데, 이는 암 또는 심장병 등을 유발시키는 원인이 될수 있음으로 인체에 매우 유해하다 [3,4]. 우리는 식품의약품안정청에서 규제하고 있는, 카바마이드 퍼옥사이드(15%)를 사용하였다. 카마바이드 퍼옥사이드(15%), 수증기, 저온 대기압 플라즈마 제트를 사용하여 미백효과를 관찰하였다. 기체 유량은 1,000 sccm 이며, 공기와 질소를 사용하였다. 미백효과를 보기 위한 대상으로는 우치(牛齒)를 사용하였으며, 플라즈마를 처리하여 미백효과를 관찰하였다. 실험 대조시료군으로는 카바마이드 퍼옥사이드(15%)와 수증기(0.4%)를 첨가한 다음, 공기 플라즈마와 질소 플라즈마를 조사하여 비교해보았다. 수증기를 첨가한 이유는 활성산소의 농도를 높이기 위함이며, 탁월한 미백효과를 얻을 수 있다. 실험을 통하여 우치에 카바마이드 퍼옥사이드(15%)와 수증기(0.4%)를 처리한 경우 플라즈마의 미백효과가 탁월함을 보였다. 이때 CIE색좌표 ($L^*a^*b^*$)에서 명도도가 높아짐을 보았다. 미백효과에 대한 측정은 측색분광기(cm-3500d)를 이용하였다. 라만은 빛이 어떤 매질을 통과할 때 빛의 파장을 변화시켜 빛의 일부는 진행방향에서 이탈해 다른방향으로지행하는 현상을 산란이라고 한다. 이를 이용하여 빛의 파장을 변화시키는 현상을 라만산란이라고 한다. 이것을 이용하여 같은 우치의 표면을 플라즈마 처리 전 후를 라만을 통해 측정하였다. 대기압 저온 플라즈마에서 발생되는 ROS는 미백효과에 큰 영향을 미친다. 모든 실험의 플라즈마 처리시간은 최대 20분까지로 하였다.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.27-35
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• 2003

No currently available methods to monitor pathogenic protozoa, Cryptosporidium and Giardia in environmental water come close to acceptable sensitivity, specificity and reproducibility, and so it has to be accompanied by thorough quality control and performance evaluation to credibly predict the distribution of them. We collected surface water samples from the Han River and spiked our prepared (oo)cysts, determined Matrix Spike recoveries using USEPA Method 1623 and considered what factors influence MS recovery and validity. As a result, average 46% of spiked oocysts and 60% of spike cysts were recovered, but repetitive sampling and statistical approach seemed to be necessary to determine the environmental pollution level of two protozoa as their variation coefficients was so much as 35oio and 26%. And MS recoveries with two acid dissociations during immunomagnetic separation were improved more 10% than that with one dissociations and the use of spiked suspension enumerated by flow cytometry instead of manual preparation enhanced the validity and reliability in spiking tests. Because fluorescence characteristics of (oo)cysts stained on well slides with FITC-labeled monoclonal antibodies and DAPI was not always same, well Elides from spiked field samples were helpful to evaluate the performance of staining. We found many (oo)cyst-like objects with typical fluorescence, not (co)cysts, from the Han River water samples, and then it was concluded that nuclei staining by DAPI (4',6-diamidino-2-phenylindole) and examination by Differential Interference Contrast Microscope should be critical for valid identification.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.312-316
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• 2013

The objective of this study was to establish an analytical method to detect zearalenone (ZEA) in herbal medicines and their decoctions and investigate the ZEA transfer rate from raw materials of herbal medicines to their decoctions. Herbal medicines (Trichosanthis Semenm, Eucommiae Cortex, Rubi Fructus) spiked with a known concentration of ZEA were presoaked or unsoaked (as a pretreatment) and boiled for 3 h at $100^{\circ}C$ or autoclaved for 1 h at $121^{\circ}C$. The decoction and the remnants were separated, cleaned up with an immunoaffinity column, and analyzed using HPLC. Recoveries for decoctions and remnants were 68.39-83.68% and 72.91-80.25%, respectively. ZEA was not detected in the decoction, whereas it was found in the remnants. Although ZEA in the raw material of herbal medicines was not transferred into the decoction during heating and autoclaving, the continuous monitoring for ZEA in raw herbal medicines should be carried out for the safe ingestion and utilization of herbal medicines.

• Journal of Food Hygiene and Safety
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• v.3 no.2
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• pp.65-73
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• 1988

T-2 toxin is one of mycotoxins produced by fungi such as Fusarium spp. and possesses a potent cytotoxicity to eukaryotic cell. The contamination of mycotoxins in cereals and feedstuffs is one of the great concerns in health authorities. Therefore, the development of the specific, sensitive and simplified analysis method for T -2 toxin is required. During more than ten years, several chemical and biological analysis methods were proposed and applied for the detection and quantification of T-2 toxin. TLC, GLC-FID and GC-MS are widely employed, but these methods required numerous clean-up procedures before analysis, and the detection limit for T-2 toxin is more than 10 ppb. Biological analysis methods with dermal tissues and cultured cells are not specific to T-2 toxin, since T-2 toxin and other related derivatives possess a similar toxicological activity although their relative activity is different each otber. Based on tbe specific reaction between antibody and antigen, the authors tried to introduce the immunochemical methods for determination of T-2 toxin. The enzyme-linked immunosorbent assay method using monoclonal antibody for T-2 toxin was applied to analyse T-2 toxin. The detection limit of T-2 toxin by ELISA method was 0.1 ppb. The correlation between ELISA and GC-MS method on these samples was very high. ELISA method developed for the detection and quantification of T -2 toxin in this paper possesses simplicity, high sensitivity and specific for T-2 toxin. Furthermore, the ELISA method with T-2 toxin monoclonal antibody was an excellent tool for the screening of Fusarium spp. which was suspected to produce T-2 toxin.