Removal of filamentous algae by positively charged bubble flotation : a comparative study with spherical/ spherical-like shapes

Bui Thi Thuy 서울대학교 대학원 2014 국내석사

Abstract Removal of filamentous algae by positively charged bubble flotation: a comparative study with spherical/ spherical-like shapes Bui Thi Thuy Dept. of Civil and Environmental Engineering College of Engineering Seoul National University The objective of this study was to compare removals of filamentous algae with spherical/ spherical-like algae during charged bubble flotation process, optimize operation conditions for better removal of filamentous algae and observe the change of algal morphology to identify mechanisms underlying the efficiency of flotation with positively charged bubbles. Three selected shapes in this research are spherical (Microcystis sp.), oval (Chlamydomonas angulosa) and filamentous algae (Phormidium sp.), cultured in the laboratory under certain cultivated conditions. Physical properties of three differing algae were understood as morphology, size distribution and zeta potential in various pH. Under pH conditions of 4.5~7, all algae species showed negative charges; -10 mV for filamentous shape, ~ -20 mV for oval shape and ~ -40 mV for spherical shape. The size of these shapes ordered increasingly as spherical < oval < filamentous algae. Removal of differing algal shapes were conducted by the batch dissolved air flotation (BDAF) method with bubble generation from saturated pressure of 6 bars, in the presence of aluminium at 30% of bubble rate. Filamentous algae presented the greatest results (i.e. 86% for cell removal and ~93% for chlorophyll a reduction) when comparing to spherical/ spherical-like algae (i.e. ~75% for cell removal and ~80% for chlorophyll a reduction). For better filamentous algal removal, the optimum operational condition was also investigated. Bubbles were generated at two levels of saturated pressure (3 bars, 6 bars) and measured at different bubble concentrations (10%, 20%, and 30%), in the absence and presence of coagulants. Bubbles averaging 30 µm and 45 µm in size were observed at zeta potentials of -30 mV~+27 mV. We obtained optimal filamentous algal removal with positively charged bubble flotation at a 30% bubble rate at >16 mV and a bubble size of 30 µm, with removal of up to 85% and 93% of cells and chlorophyll a, respectively. Also, by positively charged bubble flotation, only filamentous cell changed its size arrangement and promoted spherically or ovally being to adopt with the stress environment. We also demonstrated the efficacy of using positively charged bubbles to remove filamentous cells and the importance of positively charged bubbles in the rarely reported interaction between bubbles and chain-like algae. Keywords: Bubble generation conditions, chain-like algae, filamentous algae removal, flotation, positively charged bubble, zeta potential Student number: 2012-23968

Rad51-associate protein 1 interacts with NS5A and regulates hepatitis C virus propagation : C형간염바이러스 NS5A 단백질과 결합하는 RAD51AP1 세포 단백질에 관한 연구

Nguyen Thuy Thuy Tram 한림대학교 대학원 2017 국내석사

Background: The life cycle of hepatitis C virus (HCV) is highly dependent on host cellular proteins for its propagation. In order to identify the cellular factors involved in HCV propagation, we performed protein microarray assay using the HCV NS5A protein as a probe. Of ~9,000 human cellular proteins immobilized in a microarray, approximately 90 cellular proteins were identified as NS5A interacting partners. Of these candidates, RAD51-associated protein 1 (RAD51AP1), which is a dsDNA, ssDNA and RNA binding protein is selected for further study. It is a member of the multiprotein complexes postulated to carry out homologous recombination and DNA repair in mammalian cells. RAD51AP1 synergizes with UAF1 to enhance RAD51-mediated homologous DNA pairing specifically by promoting the assembly of the synaptic complex, in which single-stranded DNA derived from the nucleolytic processing of a primary lesion is homologously aligned with a duplex molecule. RAD51AP1 knockdown cells tend to hypersensitizes to DNA-damaging agents and prone to chromatid breaks. Methods: By using microarray screening, we identified RAD51AP1 as one of 90 NS5A interacting partners. Results: We confirm that NS5A directly bounds to RAD51AP1 and further demonstrate that NS5A can enhance the protein level, but not RNA level of RAD51AP1 through ubiquitin-proteosome pathway. NS5A also disrupts the interaction between RAD51AP1 and UAF1, therefore impairs the trimeric complex of RAD51, RAD51AP1 and UAF1. Silencing of RAD51AP1 inhibits viral infection, whereas overexpression of RAD51AP1 increases HCV late step. Importantly, RAD51AP1 plays a role in the assembly step by acting as a bridge to transfer HCV RNA to NS5A. Conclusions: Our findings provide insights into the function of RAD51AP1 in the life cycle as well as the pathogenesis of HCV.

Irisin attenuates hepatic stellate cell activation and liver fibrosis in bile duct ligation mice model and improves mitochondrial dysfunction

Lai Thuy Linh 강원대학교 대학원 2024 국내석사

Background: Liver fibrosis is a common outcome of chronic liver disease and is primarily driven by hepatic stellate cell (HSC) activation. Irisin, a myokine released during physical exercise, is beneficial for metabolic disorders and mitochondrial dysfunction. This study aimed to discover the effects of irisin on liver fibrosis in HSCs, a bile duct ligation (BDL) mouse model, and the associated mitochondrial dysfunction. Methods: In vitro experiments utilized LX-2 cells, a human HSC line, stimulated with transforming growth factor beta 1 (TGF-β1) which is a major regulator of HSC fibrosis, with or without irisin. Mitochondrial function was assessed using mitochondrial fission markers, transmission electron microscopy, mitochondrial membrane potential, and adenosine triphosphate production. In vivo, liver fibrosis was induced in mice via BDL, followed by daily intraperitoneal injections of irisin (100 µg/kg/day) for 10 days. Results: In vitro, irisin mitigated HSC activation and reduced reactive oxygen species associated with the TGF-β1/Smad signaling pathway. Irisin restored TGF-β1-induced increases in fission markers (Fis1, p-DRP1) and reversed the decreased expression of TFAM and Sirt3. Additionally, irisin restored mitochondrial membrane potential and adenosine triphosphate production lowered by TGF-β1 treatment. In vivo, irisin ameliorated the elevated liver-to-body weight ratio induced by BDL and alleviated liver fibrosis, as evidenced by Masson’s trichrome staining. Irisin also improved mitochondrial dysfunction induced by BDL surgery. Conclusion: Irisin effectively attenuated HSC activation, ameliorated liver fibrosis in BDL mice, and improved associated mitochondrial dysfunction. These findings highlight the therapeutic potential of irisin for the treatment of liver fibrosis. Keywords: liver fibrosis, irisin, hepatic stellate cells, mitochondrial dysfunction, TGF-β1

Studies on tryptophan dependent and independent secretion mechanisms of tryptophanyl-tRNA synthetase: Pathophysiological implications for innate immune responses

NGUYEN THUY THUY TRAM 가천대학교 대학원 2023 국내박사

While cytoplasmic tryptophanyl-tRNA synthetase (WARS1) ligates tryptophan (Trp) to its cognate tRNAs for protein synthesis, it also acts as an innate immune activator in extracellular space. However, its secretion mechanism remains elusive. Here, we report that in response to stimuli WARS1 can be secreted via two distinct pathways: via Trp-dependent secretion of naked protein and via Trp-independent plasma membrane-derived vesicles (PMVs). In the direct pathway, Trp binding to WARS1 induces a “closed” conformation, generating a hydrophobic surface and basic pocket. The Trp-bound WARS1 then binds stable phosphatidylinositol (4,5)-biphosphate and inner plasma membrane leaflet, passing across the membrane. In the PMV-mediated secretion, WARS1 recruits calpain 2, which is activated by calcium. WARS1 released from PMVs induces inflammatory responses in vivo. These results shed a light into the WARS1’s secretion mechanisms and improve our understanding how WARS1 is involved in the control of local and systemic inflammation upon infection.

Development and Evaluation of the Cultural Competence Course for Vietnamese Nursing Students

Ho Thi Thuy Trang 인제대학교 일반대학원 2020 국내석사

ABSTRACT Development and Evaluation of the Cultural Competence Course for Vietnamese Nursing Students Ho Thi Thuy Trang (Advisor: Prof. Jina Oh, R.N, Ph.D.) Department of Nursing Graduate School, Inje University This study was supported by the Global Korea Scholarship (GKS) of the National Institute for International Education under the Ministry of Education, Korea (grant number KGSP-GRA-2016-683). Background: Cultural competence is crucial competence for both health care providers and student to promote health outcome and quality of care. The purposes of study were develop and evaluate the effectiveness of cultural competence intervention on the level of cultural competency on Vietnamese nursing students in a Bachelor of Science in nursing program Methods: The cultural competence program was developed and evaluated based on five phase of ADDIE model. The participants were encouraged cultural competence in context of knowledge, attitude and skill through diverse teaching methods. The instructional materials were contributed from movie and documentary, presentation, and service learning. Evaluation tools included self-evaluation and focus group interview. A pretest- posttest, one control and two experimental groups, and quasi experimental design were used with 60 nursing students who participated in the program. Results: The findings indicated that significant group by time interactions in total cultural competence score (F=66.73, p<.001) was found. Participant’s perception about effect of training expressed three categories “journey toward cultural competence”, “satisfaction of cultural nursing competence course”, and “suggestion for improvement”. Besides, no statistically significant differences between stand-alone cultural course, and cultural course with service learning were revealed. “Obtaining culture’s perspective through real experience”; and “expanding understanding of cultural competence through service learning” were immersed from participants having service learning. Conclusions: This study found that cultural competence course was developed systematically to adopt student’s educational need; and had effective on student’s cultural competence. It also provides evidence on the effects of cultural competence course in theoretical and practice aspects should be considered in the future. Furthermore, cultural competence issue should expand and incorporate nursing curricula.

이온성 액체의 생분해성과 생태 독성효과

Pham Thi Phuong Thuy 전북대학교 대학원 2007 국내석사

이온성 액체는 휘발성 유기용매를 대체할 수 있는 청정용매로, 여러 공정에 이용할 수 있는 액체상태의 소금이다. 이온성 액체는 구조를 변화시키거나 양이온과 음이온의 구성을 바꿈으로써 산업공정의 사용에 적합하도록 화학적, 물리학적 특성을 변화 시킬 수 있다. 이렇게 합성된 이온성 액체가 지속 가능한 화학물질이 되기 위해서는 이온성 액체의 생물학적 행동에 대한 평가가 반드시 수행되어야 한다. 그러므로 본 연구자는 전세계적으로 데이터가 미흡한 이온성 액체의 생태독성과 생 분해성에 대한 조사를 실시 하였다. 음이온으로 bromide 결합하고 각각 알킬 체인의 길이가 3, 4, 6, 8개인 양이온 1-alkyl-3-methylimidazolium, 1-alkyl-3-methylpyridinium, 1-alkyl-1-methylpyrrolidinium의 독성을 측정하기 위하여 미세 녹조류 (Pseudokirchneriella subcapitata)를 선정하였다. 독성 측정방법으로는 OECD [Organization for Economic Cooperation and Development] 와 EPA [Environmental Protection Agency]에서 참조된 성장반응 실험이 실시 되었으며, 조류의 광합성 특성을 기초로 고안된 독성 측정장치를 통해 이루어졌다. 실험결과 두 가지 실험 방법에서 양이온의 종류에 관계없이 알킬 체인의 길이가 증가할수록 독성이 증가되는 것을 확인할 수 있었다. 양이온의 종류에 따른 독성 평가 경우, imidazolium과 pyridinium이 pyrrolidinium보다 독성이 더 강하게 측정되어서 실험된 이온성 액체 중 pyrrolidinium이 가장 친환경적 화학구조를 가진 것으로 판단할 수 있었다. 폐수나 하수 처리공정에서 이온성 액체의 처리 가능성과 분해과정을 확인하기 위하여 생 분해성 실험을 실시하였다. 활성오니는 전주시 하수처리장에서 채취하였으며 2 달간의 시간 동안 이온성 액체의 생 분해성 과정을 HPLC와 LC-MS로 측정하였다. 실험결과 dialkylimidazolium과 dialkylpyridinium 염은 각기 다른 알킬 체인 부분의 산화 과정을 통해 생 분해 된 것을 확인 할 수 있었다. Imidazolium염의 경우 1-(1-hydroxybutyl)-3-methylimidazolium, 1-(3-hydroxybutyl)-3-methylimidazolium, 1-butyl-3-hydroxymethyl imidazolium, 1-methyl-3-(3-oxobutyl)imidazolium, methylimidazole, butylimidazole의 중간체를 관찰할 수 있었으며, pyridinium의 경우 1-hydroxybutyl-3-methylpyridinium, 1-(2-hydroxybutal)-3-methylpyridinium, 1-(2-hydroxyethyl)-3-methylpyridinium and methylpyridine의 중간체를 확인할 수 있었다.

Reduced graphene oxide field-effect transistor with indium tin oxide extended gate for proton sensing

Thuy, Kieu Truong Sungkyunkwan University 2013 국내석사

In this study, reduced graphene oxide field-effect transistor (R-GO FET) with indium tin oxide (ITO) extended gate electrode was demonstrated as a transducer for a proton sensing application. In this structure, the sensing area is isolated from the active area of the R-GO FET. The ITO extended gate electrode was also used as a proton sensing area. The proton sensing properties based on the R-GO FET transducer were analyzed. The R-GO FET device with the encapsulation by tetratetracontane (TTC) layer showed a good stability in the electrolytic solutions. The device showed an ambipolar behavior with the Dirac point shift versus the pH change in the electrolyte. pH sensitivity based on the Dirac point shift as a sensing parameter was about 43 ~ 50 mV/pH in a wide range of pH value 2~12. The sensor has offered a potential for sensing of H+ in the electrolytes and the sensing area can be modified further for various ions sensing applications.

하천수 중 NOM과 하수방류수 중 인 처리를 위한 알루미늄계 응집제의 적용

TRINH THUY KHANH 부경대학교 대학원 2012 국내박사

Using aluminium based coagulants for the removal of natural organic matter and turbidity from surface water and phosphorus from sewage effluent were investigated. Conventional Al salts, such as alum and AlCl3, and Polyaluminum Chlorides (PACl) with different r (r = [OH]/[Al]) values were prepared in laboratory. Based on the difference in reaction kinetics of Al species and ferron reagent, the hydrolytic Al species in aluminum based coagulants were classified as fast reacting monomeric Ala, slow reacting polymeric Alb, and very slow/ or non reacting colloidal/precipitate Alc. The results showed that the higher the r value of PACl, the lower the Ala and the higher the Alb and Alc obtained. The characteristics of raw waters were analysed before performing jar tests. Various fractions of dissolved organic matter (DOM) in The Nakdong River water (Busan, Korea), such as hydrophobic acid, hydrophilic acid, and transphilic organic were isolated and coagulation behavior of each fraction was investigated. Also, phosphorus in sewage effluent from Nambu Sewage Treatment Plants was classified as organic-, condensed-, and ortho-P. Preformed monomeric Ala is the most unstable species and quickly transformed to other Al species while preformed Alb and Alc were relatively stable during coagulation. Performance of the coagulants was controlled not only by preformed species but also by those forming in situ during coagulation. The presence of Al species formed in situ strongly depends on coagulant dose and coagulation pH. At neutral and basic pHs, PACls containing more stable preformed Alb were more efficient for turbidity and organic matter removal. At slightly acidic pH, predominant Ala coagulants were more efficient since more Alb was formed in situ at this condition. Experiments with isolated hydrophilic acids, humic acids, and fulvic acids also indicated Alb was effective for removal of hydrophilic acids, the organic fraction that is most difficult to coagulate. Alb (preformed and in situ formed), therefore was effective for removal of turbidity and NOM. However, at high Al doses and high pH, where Alc was the predominant species formed in situ, the superior performance of Alb in removing of turbidity disappeared. Due to its bulky structure which is effective in sweep flocs mechanism, Alc is the most effective species for turbidity removal. Experiments conducted with sewage effluent showed that phosphorus removal was correlated well with the content of Ala in coagulants. Positive effects of Ala for the removal of P might be due to high ability of monomeric Al in forming the Al(OH)x(PO43-)3-x precipitates and in adsorption of phosphates into aluminum hydroxide precipitates that are formed predominantly in hydrolysis process of Ala coagulants. Alb, although has been known as the most effective species in removal of organic matter, did not show any superior performance in P removal. Alc (preformed and in situ formed) might be favorable for adsorption of P and this species also showed a positive effect on removal of suspended P due to its superior performance in removal of turbidity from water. The residual P concentrations obtained were strongly depended on the coagulant type used, or the contents of Ala, Alb, and Alc in the coagulants. Results obtained from the study could be used for making an appropriate coagulant for a preferential aim of coagulation. Prehydrolyzed degree of PACl (r value) used should be determined according to a specific water characteristic and a target substance that need to be removed during coagulation.

The study on the role of Helicobacter pylori and its cytotoxin-associated gene A (CagA) in TGF-β signaling

Thuy Trang Nguyen 가천의과학대학교 대학원 2011 국내석사

Helicobacter pylori infection causes chronic gastric inflammation and peptic ulceration, and is an important risk factor for the development of gastric cancer. The cytotoxin-associated gene A (CagA), one of the most important virulence factors of H. pylori, is believed to contribute to the gastric tissue injury and cancer development. Transforming growth factor-β (TGF-β) signaling plays a pivotal role in modulating gastric mucosal inflammatory responses, whereas dysregulation of TGF-β signaling has been associated with development of gastric cancer. H. pylori infection has been reported to be associated with decrease in TGF-β signaling. However, the precise underlying mechanism of H. pylori infection on TGF-β signaling and inflammatory response remains unclear. In this study, I investigated the mechanism of inhibition of TGF-β signaling by H. pylori and CagA protein. Expression of CagA suppressed TGF-β/Smad transcriptional response in human gastric cells. CagA interacted constitutively with Smad proteins, and most strongly with Smad3. CagA suppressed TGF-β-induced expression of target genes such as PAI-1, firbonectin, and ID3. Moreover, CagA inhibited TGF-β-induced down-regulation of inflammatory chemokines including IL-8, CXCL1, and CXCL3. These results suggest that the attenuated TGF-β signaling associated with CagA-positive H. pylori infection could be important determinant for the degree of inflammation and development of gastric cancer provoked by H. pylori. 헬리코박터 파일로리 (Helicobacter pylori)의 감염은 위산 분비, 소화성 궤양, 위축성 위염 (atrophic gastritis) 및 장상피화생 (intestinal metaplasia)을 유발하며, 만성적 감염은 위암을 유발하는 위험인자로서 세계보건기구에서 발암인자로 규정하고 있다. H. pylori감염은 위의 상피세포에서 TNF-α, IL-β, IL-8 등의 염증성 사이토카인의 생성을 촉진시킨다. H. pylori의 병원성 인자로는 cytotoxin-associated gene (CagA), vacuolating cytotoxin gene (VacA), BabA, OipA 등 다양한 독성인자가 존재한다. 특히, CagA는 가장 위험한 독성인자의 하나로 숙주세포에 들어가 생체 내 신호전달에 영향을 주며 위축성 위염 및 위암 발생과 연관이 있는 것으로 알려져 있다. 본 연구에서는 점막 면역과 암 발생에 있어 중요한 역할을 하는 형질전환인자-베타 (transforming growth factor-β, TGF-β)의 신호전달에 있어 H. pylori와 CagA 인자의 역할을 중심으로 연구하였다. 인간 위암세포주 AGS 세포에 있어 CagA양성H. pylori의 감염이나 CagA 유전자의 발현은 TGF-β/Smad의 전사활성을 억제하는 것으로 나타났다. 이러한 저해활성에 대한 자세한 분자생물학적 기전을 분석한 결과, H. pylori의 CagA 단백질은 TGF-β 신호전달의 중요한 매개체인 Smad 단백질인 Smad2, Smad3 및 Smad4와 결합하는 것으로 나타났다. 특히 Smad3와 가장 강한 결합활성을 보였으며, Smad3의 MH2 도메인이 CagA단백질과 결합하는 부위임을 확인하였다. 이러한 CagA 단백질과 Smad3간의 결합은 세포 내에서 TGF-β에 의해 활성화되는 Smad복합체의 형성을 저해하였으며, 또한 유전자 발현을 위한 Smad3의 핵내 이동을 억제한다는 사실을 확인하였다. AGS 세포에 있어서 CagA 유전자의 발현은 TGF-β에 의해 유도되는 유전자, 예를 들어 PAI-1, fibronectin, 및 Id3의 발현을 억제하였다. 또한 CagA의 발현은 TGF-β에 의해 억제되고 있는 염증성 케모카인, IL-8, CXCL1 및 CXCL3의 발현 조절을 저해하는 것으로 나타났다. 이러한 연구결과는 H. pylori, 특히 CagA-양성 H. pylori의 감염이 생체 내 항상성 유지에 중요한 역할을 하는 TGF-β 신호를 억제함으로써 염증반응을 증폭시키고, 또한 위암 유발 의 가능성을 증가시키는 기전으로 작용하는 것으로 사료되었다.

Characterization of nitrogen metabolism related genes in rice

Thuy Vo Thi Bich 경희대학교 2013 국내석사

Nowadays, improving nitrogen use efficiency (NUE) becomes one of the most important goals for agriculture and biotechnology. The main components of NUE are the efficiency of nitrogen (N) uptake and the efficiency of N utilization to increase grain yields. Inorganic nitrogen sources (nitrate or ammonium) are assimilated and utilized within plants by organic forms (amino acids). GS/GOGAT (glutamine synthetase/glutamate synthase) pathway is a major route for ammonium assimilation, and there also have three important enzymes including glutamate dehydrogenase, asparagine synthetase and aspartate aminotransferase which have important functions in N assimilation metabolism. Because N and carbon (C) metabolism coordinates together, fine tuning of both N and C metabolism is necessary to enhance NUE for taking advanced agricultures. Under nutrient deficiency or sufficiency conditions, plants alter assimilate partitioning between organs and thus represents specific phenotypes. However, one of the most challenges for plants is how they distribute nutrients to support their growth under various conditions. In this study, we characterized null mutants of C metabolism related genes generated by T-DNA insertions for examining their growth on the media with different combination of C and N sources, and investigated the effects of C metabolism related genes for plant growth under different conditions. Plants have the nitrogen sensing and signaling systems to manage the nitrogen status for efficiently utilizing the nitrogen sources as well as coping with the nutrient deficiency environments. One of candidate nitrogen sensing in plants is PII-mediated nitrogen regulator system. Although this sensing system was extensively identified in E. coli and cyanobacteria, they have been still unclear in higher plants. In this study, we isolated T-DNA mutant lines for N metabolisms for examining their growth on the media with different N sources as well as for identifying some candidate nitrogen sensors in rice. Our present results based on expression levels and morphological analysis under conditional media firstly prove the effect of some N related genes to rice growth and development.