• 멤브레인
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• 제32권1호
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• pp.66-73
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• 2022

본 연구에서는 stainless steel로 재질로 된 금속평막모듈을 이용하여 고플럭스가 유지되면서 처리수의 안정화 방안을 모색하였다. 이 모듈은 기공사이즈가 13 ㎛ 단위여서 플럭스가 60 LMH에서 100 LMH까지 고플럭스로 운전이 가능하다 그러나 SS가 초기 운전 시 30~50 ppm 정도 유출되지만 SS가 응집핵으로 작용하므로 응집이 가능하게 된다. 기존 고분자막 여과수는 응집핵이 없어서 coagulation은 되지만 floculation이 안되므로 추가적으로 응집보조제인 clay나 벤토나이트를 투여하게 되는데 본 연구에서는 이런 응집보조제 필요 없이 SS 누출만으로 floculation이 되므로 총인처리와 처리수질이 안정성을 도모하고자 하였다. 최종적으로 안정적인 처리수에 고플럭스가 가능한 Metal필터 운전이 MBR 시스템에서 적용가능한지 타당성을 연구하고자 하였다.

• 상하수도학회지
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• 제22권3호
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• pp.281-288
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• 2008

Cake resistance is influenced by floc size deposited on membrane surface. Enlarging floc size can reduce cake resistance. The small particles are enlarged by coagulation and flocculation process in conventional mixing tank at membrane filtration system. Fully-grown flocs for reducing the cake resistance, however, are ruptured while passing through a pump. In light of this fact, this study aims to experimentally look at the reaggregation phenomenon of mixing system. In addition, reaggregation phenomenon of mixing system is compared with first-aggregation of in-line injection system in which coagulant is injected just before a pump. These results suggest that first-aggregation of in-line injection system is better than reaggregation of mixing system for G-value above $3100sec^{-1}$. Since G-value in pipe of actual membrane filtration system are usually larger than $3100sec^{-1}$. The performance of in-line injection system is expected to be better than the conventional mixing tank system.

• 상하수도학회지
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• 제17권4호
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• pp.519-527
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• 2003

Cake layer in crossflow microfiltration(CFMF) can be reduced by coagulation, enhancing membrane flux. This is because enlarging particle size by coagulation increases shear-induced diffusivity and the back-transport of rejected particles. However it is known that the enlarged particles are disaggregated by the shear force of the pump while passing through it. This study is to look at the disaggregation in relation with cake layer reducation. Kaolin and polysulfon hollow fiber microfilter are used for experiment. The reduction of cake resistance by coagulation is observed in a range of 17% to 53% at the various coagulation conditions. The particle size analysis results of the experiments show that aggregated particles in feed are completely disaggregated by pump but re-aggregation of particles occurs in membrane. This suggestes that the re-aggregation of particles is critical to cake reduction and flux enhancement, since the aggregated particles are completely broken. The mechanisms for re-aggregation in membrane are the same with those for coagulation in feed tank. Charge neutralization is better for CCFMF than sweep flocculation although it has two drawbacks in operation.

• 약학회지
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• 제43권6호
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• pp.802-808
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• 1999

Vibrio vulnificus cytolysin has been incriminated as one of the important virulence determinants in V. vulnificus infection. In the present study, the effects of Vibrio vulnificus cytolysin on platelets were examined. Vibrio vulnificus cytolysin induced platelet aggregation and increased intracellular calcium concentration ($[Ca^{2+}]_i$) of rat platelets. These effects were abolished in $Ca^{2+}-free$ buffer (2 mM EGTA). Cytolysin also potentiated ADP-and collagen-induced platelet aggregation. Lanthanum (2 mM) inhibited cytolysin-diduced platelet aggregation. However, another $Ca^{2+}$ channel blockers, verapamil ($20{\;}{\mu}M$) or mefenamic acid ($20{\;}{\mu}M$) did not block cytolysin-induced platelet aggregation. Osmotic protectants, sucrose (50 mM) and raffinose (50 nM) suppressed platelet aggregation by 35.9% and 63.4%, respectively. V. vulnificus cytolysin increased membrane conductances of platelet membranes. These results suggest that cytolysin-induced platelet aggregation is mediated via lanthanum sensitive-calcium influx which resulted from the pore formation by V. vulnificus cytolysin.

• BMB Reports
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• 제38권4호
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• pp.407-413
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• 2005

Calcium and zinc binding protein, calprotectin is a multifunctional protein with broad spectrum antimicrobial and antitumoural activity. It was purified from human neutrophil, using a two-step ion exchange chromatography. Since surface hydrophobicity of calprotectin may be important in membrane anchoring, membrane penetration, subunits oligomerization and some biological roles of protein, in this study attempted to explore the effect of calcium in physiological range on the calprotectin lipophilicity. Incubation of human calprotectin ($50\;{\mu}g/ml$) with different calcium concentrations showed that 1-anilino-8-naphthalene sulfonic acid (ANS) fluorescence intensity of the protein significantly elevates with calcium in a dose dependent manner, suggesting an increase in calprotectin surface hydrophobicity upon calcium binding. Our study also indicates that calcium at higher concentrations (6, 8 and 10 mM) induces aggregation of human calprotectin. Our finding demonstrates that the starting time and the rate constant of calprotectin aggregation depend on the calcium concentration.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.177-177
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• 1998

In the previous report, tetrandrine (TET) and fangchinoline (FAN) showed antithrombotic and antiplatelet aggregation activities. The present study was undertaken to investigate the effects of tetrandrine and fangchinoline on human platelet aggregation, formation of thromboxane B$_2$ and coagulation of platelet poor plasma. TET and FAN inhibited platelet activating factor (PAF) induced human platelet aggregation, but didn't inhibit the specific binding of PAF to its receptor. Meanwhile, TET and FAN also inhibited PAF, thrombin and arachidonic acid induced thromboxane B$_2$ formation in human washed platelets. In addition, neither TET nor FAN showed any anticoagulation activities in the measurement of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using human platelet poor plasma. These results suggest that antithrombotic effects of TET and FAN in mice may be mainly related to the antiplatelet aggregation activities, and the antiplatelet aggregation effects may be related to the intracellular messenger system such as TXA$_2$ formation etc., but not to the binding of PAF to PAF-receptor on the platelet membrane directly.

• Journal of Chest Surgery
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• 제36권9호
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• pp.666-673
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• 2003

폐암의 주된 원인으로 알려진 흡연은 그 악성세포 발현기전이 아직 정확히 규명된 바 없다. 이에 저자들은 흡연에 의한 발암성의 지표로 흡연 중에 특이적으로 존재하는 강력한 발암물질인 NNK(4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone)를 이용하여 흡연에 따른 폐암의 발생과 그 Protein kinase C (PKC) isoform과 관련된 기전에 관한 연구를 시도하였다. 대상 및 방법: 인체 상피세포를 NNK에 노출시킨 후 saturation density, soft agar colony formation, cell aggregation 및 foci의 출현 등의 양상을 파악하여 세포 발암성 여부를 관찰하였으며 NNK를 15분간 노출시킨 후 PKC의 변화는 세포 내 PKC isoform의 양을 cytosolic fraction과 membrane fraction으로 분리하여 측정하여 분석하였다. 결과: NNK 투여군에서 saturation density, soft agar colony formation, cell aggregation 및 foci의 출현 시기 등의 세포 발암성을 뚜렷이 나타내었으며 PKC isoform분석의 경우 PKC-$\alpha$의 membrane fraction의 뚜렷한 증가를 보였으며 이러한 활성은 용량-의존적인 형태를 유지하였다. PKC-$\varepsilon$은 NNK 처리 시 용량-의존적으로 cytosol fraction의 감소 및 membrane fraction의 증가를 뚜렷하게 보였고 NNK에 의한 PKC-λ의 변화는 감지되지 않았다. 결론: 본 연구는 화학적 발암물질인 NNK가 인체발암화에 관여함을 재차 확인하면서 초기 과정에 관여하는 PKC isoform의 변화를 분석함으로써 total PKC활성이 아닌 isoform 각각에 대한 변화를 확인하였다는 점에서 앞으로 인체상피세포 기원의 폐암 생성 기전 연구에 기여할 것으로 생각한다.

• Toxicological Research
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• 제6권1호
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• pp.109-119
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• 1990

Ro09-0198, a cyclic peptide isolated from culture filtrates of Streptoverticillium griseoverticillatum, induced lysis of erythrocytes. Ro-09-0198-induced hemolysis was temperature-dependent and the sensitivity of hemolysis differed greatly among animal species. Preincubation of the peptide with phosphatidylethanolamine reduced the hemolytic activity, whereas other phospholipids present in erythrocytes in nature had no effect. A study of the structural requirements on phosphatidylethanolamine necessary for interaction with the peptide indicates that Ro09-0198 recognizes strictly a particular chemical structure of phosphatidylethanolamine: dialkylphosphoethanolamine as well as 1-acylglycerophosphoethanolamine showed the same inhibitory effct on hemolysis induced by Ro09-0198 as diacylphosphatidyl-ethanolamine, whereas phosphoethanolamine gave no inhibitory effect. Neither phosphatidyl-N-monomethylethanolamine nor alkylphosphopropanolamine had an inhibitory effect. Proton resonances of the peptide were observed in dimethyl sulfoxide solution in the presence of 1-dodecanoyl-sn-glycerophosphoethanolamine. This peptide caused permeability increase and aggregation of liposomes containing phosphatidylethanolamine. A glycerol backbone and a primary amino group of phosphatidylethanolamine are necessary for interaction with Ro09-0198 to cause membrane damage. Ro09-0198 induced a selective permeability change on liposomes. Glucose and umbelliferyl phosphate were effluxed significantly, but sucrose was only slightly permeable and inulin could not be released. Platelet aggregation and serotonin release simultaneously induced by Ro09-0198. Addition of peptide to rat platelet, loaded with the fluorescent $Ca^{++}$ chelator quin-2, caused immediate rise in cytosolic free $Ca^{++}$ to liposomal membrane containing phosphatidylethanolamine was observed dose dependently.

• 약학회지
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• 제35권1호
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• pp.11-14
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• 1991

Ro09-0198, a cyclic peptide isolated from culture filtrates of Streptoverticillium griseove-rticillatum, induced platelet aggregation and serotonin release simultaneously. LDH release was not observed. Addition of peptide to rat platelet, loaded with $Ca^{2+}$ chelator quin-2, caused immediate rise in cytosolic free $Ca^{2+}$. Liposomal membrane containing phosphatidylethanolamine was damaged by peptide and released $^{45}Ca$ dose dependently.

• 대한치과보철학회지
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• 제17권1호
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• pp.47-59
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• 1979

In order to study the morphologic changes of the unfixed odontoblasts suspended in phenol solution of several different concentrations, the author carried out the extraction of lower incisor of S-D strain rats to collect the odontoblasts, and the cells obtained were suspended immediately in saline solution. After observing the odontoblasts in fresh state, the saline solution was substituted with 0.125%, 0.25% 0.5%, 1% and 2% diluted phenol solutions. The morphologic changes were examined with phase contrast microscope at intervals of 10, 30, and 60 minutes. The results were as follows: 1. In saline solution the odontoblast showed cytoplasmic swelling, slender cytoplasmic process, thick rim nuclear membrane with increased dark contrast, and prominent nucleoli and chromatin granules with lapse of time intervals. In accordance with time intervals, blisters appeared in the supranuclear zone and increased its size and moved outward of the cytoplasmic membrane resulting detachment from the cell membrane. The phase dark cytoplasmic granules were increased in its dark contrast and in its size. 2. In 0.125% and 0.25% phenol solution, the odontoblasts and its nucleus shrunk immeidately and its contrast of cellular components was increased. With the lapse of time, the phase-dark granules in cytoplasm were aggregated, and several blisters were formed in and out of the cells. The outline of cytoplasmic membrane was also obscured. 3. In 0.5% phenol solution, the necleus shrunk at once, but soon after it revealed karyolysis accompanying dark contrast of neclear components such as nuclear membrane, nucleoli, and chromatin granules. On the contrary, the cytoplasmic granules showed aggregation and increased dark contrast, small and large blisters were formed in and out of the odontblasts and the outline of cytoplasmic membrane became obscured. 4. In 1% phenol solution, it showed shrinkage of odontblasts and its nuclei with thick rim nuclear membrane, aggregation of chromatin granules and occasional karyorrhexis. The dark contrast of cytoplasmic granules was increased and aggregated each other. But the blister formation could not be found. 5. In 2% phenol solution, it showed the shrinkage of odontoblasts and pyknotic nuclei with increased dark contrast of nucleoli and chromatin granules. The number of cytoplasmic granules was decreased by aggregation. But the blister formation could not be found as in 1% phenol solution.