• ALGAE
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• 제21권2호
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• pp.261-266
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• 2006

The innate soluble polysaccharides and phenolic compounds of marine macroalgae are serious contaminants which interfere with experimental procedures such as restriction enzyme digestion, polymerase chain reaction (PCR) and other enzymatic reactions using extracted DNA samples. The viscous polysaccharides are co-precipitated with DNA samples by isopropanol or ethanol precipitation in conventional experiment. To overcome the problem, a method for the isolation of high molecular weight DNA from Porphyra tenera is developed with the application of diatomaceous earth column. The isolated DNAs by this method were about 50-100 kb in size and could be digested well with restriction enzymes. The nuclease activity seemed to be minimal, and high reproducibility in the arbitrary primed PCR for RAPD analyses was a distinctive feature. These results suggest that this method is very efficient in isolating nucleic acid from macroalgae including Porphyra.

• 한국식품영양과학회지
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• 제27권5호
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• pp.821-826
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• 1998

Functional properties of mucilage and pigment extracted from Opuntia ficus-indica var. saboten were determined at various temperatures, pHs and alcohol concentrations. The crude mucilage extracted from pickly pear showed pH 4.2, 0.14% total acidity and 8.1% total soluble solid content(w/w, wet basis). Polysaccharide was purified from mucilage extract by isopropanol precipitation. Intrinsic viscosity of polysaccharide was 18.1dl/g and decreased with increasing KCl concentration. Relative viscosity and color stability of mucilage extract were determined with capillary viscometer and spectrophotometer at 534nm, respectively. In additions of 1~20%(v/v) ethanol, the red pigment of mucilage extract was very stable, but relative viscosity, increased gradually. For heating above 7$0^{\circ}C$, the stability of red pigment decreased drastically, but rheological property of mucilage was not changed. During storage, the red pigment was extremely unstable at above pH 8.3. At both pH 3.0 and pH 4.2, the red pigment was the most stable at 4$^{\circ}C$ for 18 days. In the case of storage at 37$^{\circ}C$, pigment of mucilage extract at pH 3.0 was destroyed more quickly than that at pH 4.2. Natural mucilage extract(pH 4.2) showed the good stability of red pigment at 3$0^{\circ}C$ for 10 days.

• 폴리머
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• 제35권6호
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• pp.610-614
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• 2011

본 연구에서는 방사선 전조사법으로 ETFE(polyethylene-co-tetrafluoroethylene) 불소고분자 필름에 VBC(vinylbenzyl chloride) 단량체를 그래프트할 경우 사용되는 용매의 영향을 평가하였다. ETFE 필름을 전자선을 조사하여 필름에 라디칼을 형성시킨 후 톨루엔, 햅탄, 이소프로판올 등 다양한 용매로 희석된 VBC 단량체 혼합물에 넣어 그래프트 반응을 진행시켜 그래프트율을 측정하였다. VBC-g-ETFE 필름은 FTIR 기기를 사용하여 성공적으로 그래프트 되었음을 확인하였다. 여러 용매에서 제조된 필름의 기계적 강도와 필름 단면에 그래프트된 VBC 고분자의 분포도를 측정하여 용매의 영향을 평가하였다.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.131-137
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• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• 한국염색가공학회지
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• 제30권4호
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• pp.245-255
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• 2018

In this study, cotton fabrics were coated with $TiO_2$ nanoparticles using 3-mercaptopropyltrimethoxysilane(3-MPTMS), which is highly reactive to cotton fabrics, as a medium, and the characteristics, antimicrobial properties, and photodegradation properties of the fibers were measured. The manufacturing process is as follows. (1) 3-MPTMS was added to isopropanol, and $TiO_2$ colloid was added to the mixture to prepare a solution. (2) Cellulose fibers were immersed in the prepared $3-MPTMS/TiO_2$ solution, stirred for 90 minutes at $45^{\circ}C$ in a constant temperature water bath, and dried thereafter. In order to identify the morphology of the cellulose fibers coated with $TiO_2$ nanoparticles, the surface was observed with a scanning electron microscope(SEM), and SEM-EDS was measured to identify the adhesion of $TiO_2$ nanoparticles. The SEM images showed $TiO_2$ nanoparticle and 3-MPTMS coated layers on the fibers and it was identified that $TiO_2$ nanoparticles were attached to the cellulose fibers. The antimicrobial activity of $3-MPTMS/TiO_2$-treated cotton fabrics was measured using a bacterial reduction method. $3-MPTMS/TiO_2$ cellulose fibers which was irradiated by ultra violet light, showed antimicrobial activity against Escherichia coli(ATCC 43895) and Staphylococcus aureus(ATCCBAA-1707) unlike unirradiated fibers. The cellulose fibers were stained with methylene blue and the photodegradation performance of the stained fabrics was analyzed. The stained fabrics showed high degradation performance with photolytic reactions of $TiO_2$ nanoparticles.

• The Journal of Advanced Prosthodontics
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• 제14권1호
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• pp.45-55
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• 2022

PURPOSE. This in vitro study investigates the effect of different post-rinsing times and methods on the trueness and precision of denture base resin manufactured through stereolithography. MATERIALS AND METHODS. Ninety clear photopolymer resin specimens were fabricated and divided into nine groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5, 10, and 15 min using three methods-automated, ultrasonic cleaning, and hand washing. The specimens were polymerized for 30 min at 40℃. For trueness, the scanned intaglio surface of each SLA denture base was superimposed on the original standard tessellation language (STL) file using best-fit alignment (n = 10). For precision, the scanned intaglio surface of the STL file in each specimen group was superimposed across each specimen (n = 45). The root mean square error (RMSE) was measured, and the data were analyzed statistically through one-way ANOVA and Tukey test (α < .05). RESULTS. The 10-min automated group exhibited the lowest RMSE. For trueness, this was significantly different from specimens in the 5-min hand-washed group (P < .05). For precision, this was significantly different from those of other groups (P < .05), except for the 15-min automated and 15-min ultrasonic groups. The color map results indicated that the 10-min automated method exhibited the most uniform distribution of the intaglio surface adaptation. CONCLUSION. The optimal postprocessing rinsing times and methods for achieving clear photopolymer resin were found to be the automated method with rinsing times of 10 and 15 min, and the ultrasonic method with a rinsing time of 15 min.

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.561-570
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• 2023

This study was to evaluate the effect of different rinsing times and methods on the accuracy of temporary prostheses fabricated by 3D printing method. Sixty temporary prostheses were fabricated with LCD types of 3D printer(Halot-Sky, Creality, Shenzhen, China) and divided into six groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5 and 10 min using three methods-hand washed, ultrasonic cleaning, and automated washing. All specimens were polymerized for 3 minutes under the same conditions. The marginal and internal gaps of specimens were examined using a replica technique. The light-body silicone thickness was measured at 6 reference points(Absolute marginal discrepancy, Marginal, Chamfer, Axial, Angle, and Occlusal gap). All measurements were performed by a stereomicroscope. Reference point images were taken at 100× magnification and then measured using an image analysis program. Statistical analysis was performed using Two-way ANOVA, One-way ANOVA, and the Kruskal-Wallis test (p = .05). The marginal and internal gaps were statistically different according to the rinsing methods and rinsing times(p < .001). In the rinsing time, the temporary prosthesis rinsed for 5 minutes group showed higher accuracy than 10 minutes group. In the rinsing method, the hand washing group showed higher accuracy than the automated washing group.

• Membrane and Water Treatment
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• 제14권2호
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• pp.85-93
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• 2023

Membrane separation is widely used for several applications such as water treatment, membrane reactors and climate change. Cross-linked organic-inorganic hybrid polyvinylidene fluoride (PVDF) / Tetraethyl orthosilicate (TEOS) was adopted for the preparation of optimized hollow membrane (HFM) for membrane distillation or other low pressure separators for mechanical properties and permeability under varying pretreatment schemes. HFMs were prepared on semi-pilot membrane fabrication system. Novel adopted post-treatment schemes involved soaking in glycerol, magnesium sulphate (MgSO₄), sodium hypochlorite (NaOCl), and isopropanol for different durations. All fibers were characterized for morphology using a scanning electron microscope (SEM), surface roughness using atomic force microscope (AFM), elemental composition by examining Energy Dispersive Spectroscopy (EDS), water contact angle (CA°) and porosity. The performance of the fibers was evaluated for pure water permeation flux (PWF). Post-treatment with MgSO₄ gave the highest both tensile modulus and flux. Assessment of properties and performance revealed comparable results with other organic-inorganic separators, HF or flat. In spite of few reported data on post treatment using MgSO₄ in presence of TEOS, this proves the potential of low cost treatment without negative impact on other membrane properties. The flux is also comparable with hypochlorite which manifests substantial precaution requirements in actual industrial use.The relatively high values of flux/bar for sample treated with TEOS, post treated with MgSO₄ and hypochlorite are 88 and 82 LMH/bar respectively.

• 한국식품영양과학회지
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• 제18권2호
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• pp.181-188
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• 1989

우리나라 연안에서 일시에 대량으로 어획되는 멸치를 보다 효율적으로 식량화하기 위한 일련의 연구로서 선도유지제의 일종인 Bactokil (didecyl-dimethyl ammonium chloride, isopropanol 및 물의 혼합물)과 항산화제의 일종인 Taipet-F(천연 vitamin E, L-ascorbic acid, glyceride 및 몰식자산의 혼합물)처리가 마른멸치의 지질산화억제에 미치는 효과에 대하여 검토하였다. 무처리한 대조제품(C), Bactokil처리 제품(B), Taipet-F처리제품(T), Bactokil 및 Taipet-F를 동량혼합하여 처리한 제품(M)에 관계없이, 전제품 모두 저장중 휘발성염기질소는 큰 변화가 없었고, TBA값은 증가하다 감소하였으며, 과산화물값은 제품(C) 및 (B)는 TBA값과 같은 경향을 나타내었으나, 제품(M) 및 (T)는 계속 증가하는 경향을 나타내었다. 색조는 L값은 감소한 반면 a값, b값 및 ${\bigtriangleup}E$값은 증가하였고, 지용성 및 수용성갈변도는 저장기간중 증가하는 경향이었다. 관능검사결과로 미루어 보아 대조제품(C)와 Bactokil 처리제품(B)는 저장 10일째에 산화가 상당히 진행되었고, Taipet-F처리제품(T)는 산패취를 전혀 느낄 수 없었다. 이상의 결과로 미루어 보아 제품(T)가 가장 좋았고, 다음으로 제품(M), (B) 및 (C)의 순이었다. Taipet-F처리는 마른멸치의 갈변방지와 산화방지를 효과적으로 억제시킬 수 있다는 결론을 얻었다.

• 생명과학회지
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• 제27권2호
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• pp.202-210
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• 2017

토하젓에서 분리한 박테리오신 생산 균주 중 상대적으로 넓은 항균스펙트럼을 나타내는 1균주를 선발하였고 16S rRNA 유전자 염기서열 분석 결과 B. subtilis E9-1와 거의 일치하는 것으로 동정되었다. B. subtilis E9-1가 생산하는 박테리오신의 물리화학적 특성을 조사하였고, 박테리오신을 정제하였다. 이 박테리오신은 B. cereus KCCM 11204, M. luteus IAM 1056, L. monocytogenes KCCM 40307, E. faecium KCCM 12118 및 S. aureus subsp. aureus KCCM 40050 등에 대해서 항균활성을 나타내었다. pH 2.0~8.0 범위에서는 안정하였으나 8.0 이상에서는 항균활성이 감소하였다. Isopropanol, ethanol 및 methanol 등의 유기용매에서 100%까지, acetone과 acetonitrile에서는 80%까지 항균활성을 유지하였다. 내열성의 경우 $40{\sim}100^{\circ}C$에서 60분까지는 안정하게 항균활성을 보였다. 박테리오신 농도를 증가시키면서 B. cereus, L. monocytogenes, E. faecium 및 S. aureus subsp. aureus 등 시험균 4주의 감수성을 조사한 결과 농도 의존적으로 시험균의 생육이 감소하였고 이중 L. monocytogenes 의 감수성이 가장 높게 나타났다. 박테리오신의 작용양상을 알아본 결과 B. cereus와 L. monocytogenes 배양액에 박테리오신 용액을 첨가한 후 흡광도와 CFU값이 감소하여 bactericidal임을 확인하였다. 식품에 적용 가능성을 알아보기 위해 실험한 결과 3일째부터 박테리오신을 처리하지 않은 대조구에 비해 실험구에서 생균수(CFU/ml)가 감소하였다. 아세톤을 이용한 배양상등액의 농축, superdex peptide HR 10/300 column 이용한 겔여과크로마토그래피, 역상 HPLC로써 박테리오신을 정제하였다. 역상 HPLC를 통해서 정제한 박테리오신의 분자량을 tricine SDS- PAGE로 분석한 결과 약 4 kDa이었고 질량분석법으로 측정한 정확한 분자량은 3347.6 Da로 나타났다.