Carbon Nanotubes Grafted with Hyperbranched Triazine Compounds

Tingting Li,HONGXIA YAN,Tianye Liu,Chao Liu,Zhengyan Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1

In order to improve the dispersibility of carbon nanotubes (CNTs) in the resin matrix, CNTs grafted with hyperbranched triazine compound (HPTC–CNTs) was produced by four generations condensation reaction using cyanuric chloride and hexamethylenediamine. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV-Vis spectroscopy (UV-Vis) and transmission electron microscopes (TEM) were used to characterize the obtained HPTC–CNTs. The FTIR, XPS, UV-Vis and TEM analysis showed that CNTs had been successfully grafted with HPTC. The TGA showed that the content of HPTC on the surface of CNTs was about 58 wt.%. And the HPTC–CNTs had good dispersion both in water and acetone.

Moving Rate of Positive Patient Results as a Quality Control Tool for High-Sensitivity Cardiac Troponin T Assays

Li Tingting,Cao Shunwang,Wang Yi,Xiong Yujuan,He Yuting,Ke Peifeng,Huang Xianzhang 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

Background: A small shift in high-sensitivity cardiac troponin T (hs-cTnT) assays can lead to different result interpretation and consequent patient management. We explored whether a small bias could be detected using conventional internal quality control (QC) procedures, evaluated the performance of moving average (MA)-based QC procedures, and proposed a new QC procedure based on the moving rate (MR) of positive patient results of hs-cTnT assays. Methods:The ability of conventional QC to detect a 5 ng/L bias was examined using the13s/ 22s/R4s multi-rule procedure as deviation rules.We developed MA and MR procedures for the hs-cTnT assay using eight months of patient data. The performance of different MA or MR procedures was investigated by calculating the median number of patient samples affected until a bias introduced into the dataset was detected (MNPed). After comparing the MNPed across different procedures, we selected an optimal MA or MR procedure for validation. Validation graphs were plotted using the minimum, median, and maximum number of results affected until bias detection. Results: Our conventional QC procedures could not detect a positive bias of 5 ng/L. When a positive bias was introduced, MNPed was much higher using MA than using MR, with cut-off values of 5 ng/L and 14 ng/L, respectively. MR validation charts for optimal procedures provided insight into the MR performance. Conclusions: The MR procedure could detect different errors with few false alarms. In the hs-cTnT assay, the MR procedure with a smaller cut-off value outperformed MA and conventional QC procedures for small bias detection.

Acetaldehyde induces tau phosphorylation via activation of p38 MAPK/JNK and ROS production

Li Tingting,Shi Huahua,Zhao Yan 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.3

Background Heavy drinking has been associated with increased risk of dementia such as Alzheimer’s disease, but the mechanisms are not fully understood. Evidence suggests that acetaldehyde, the most toxic metabolite of ethanol, mediates the brain tissue damages and cognitive dysfunction induced by the overconsumption of alcohol. Abnormal hyperphosphorylated tau protein is the major component of neurofi brillary tangle that correlates with neurodegeneration. However, there are few reports regarding whether acetaldehyde affects the phosphorylation of tau protein in neuronal cells. Objective The aim of this study is to explore the effect of acetaldehyde on the phosphorylation of tau protein. Results It was found that acetaldehyde treatment increased the amount of phosphorylated tau in human neuroblastoma SH-SY5Y cells. Further studies revealed that acetaldehyde increased the production of reactive oxygen species (ROS) and induced the activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Pretreatment with antioxidant N -acetylcysteine (NAC) or inhibitors of p38 MAPK and JNK ameliorated the phosphorylation of tau in acetaldehyde treated cells, suggesting that acetaldehyde might increase the phosphorylation of tau via inducing the production of ROS and activating p38 MAPK and JNK pathways. Conclusion The result indicated that acetaldehyde treatment increased tau phosphorylation in neuronal cells. Therefore, the accumulation of acetaldehyde resulted from alcohol abuse or defect of acetaldehyde detoxification may promote tau pathology in neurodegenerative diseases such as AD.

Study on subway ridership estimation with the consideration of endogeneity

Tingting Li(이정정),Jungyeol Hong(홍정열),Dongjoo Park(박동주) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

본 연구는 지하철 이용자 수요예측을 위하여 내·외생적 영향요인들을 분석하고, 각 요인들이 일반선형회귀모형 상에서 내재하고 있는 편의를 통제하여 보다 설명력이 높은 예측 방법론을 제시하는데 주요 목적이 있다. 지하철 이용수요와 관련하여 기존 연구들은 주로 사회경제 및 토지이용 등의 요인들과의 상관관계 위주의 연구를 수행해 왔으나, 버스 등의 타 대중교통 수요의 내생성 및 지하철역 주변상업용도의 외생적 영향에 대한 연구는 고려하지 않았다. 따라서 본 연구는 이러한 문제들을 개선하기 위하여 2단계 최소자승법(2SLS)을 적용하였으며, 연구결과를 통하여 버스 이용자수와 상업용도 요인들의 내·외생성은 2SLS 추정에 의해 지하철 이용수요 예측을 보다 고도화 할 수 있는 것으로 나타났다. The objective of this study is to develop a consistent model for predicting subway ridership. Previous studies have focused on the relationship between subway ridership and factors such as socioeconomy and land-use. However, there was a lack of research on the endogenous impacts of alternative transit demand and exogenous trade area. Therefore, this study incorporated the effects of bus ridership and retail properties within 300m radius from 248 subway stations in Seoul in the modeling process. In a methodological aspect, we applied two-stage least squares (2SLS) approach to capturing the endogeneity issue. As a result, bus ridership and attributes for trade area were found to be significant, and the methodological approach for the model development was plausible to estimate subway ridership.

Electrospinning Inorganic/Organic Nanohybridization Membranes with Hydrophobic and Oleophobic Performance

Tingting Zhang,Zihui Li,Ya Liu,Kangjia Ding,Yangfeng Guo,Yiyang Xu,Mengfan Sun,Dongfang Wang,Qian Li 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

Polytetrafluoroethylene (PTFE) nano-porous membrane has been widely used in various fields due to its excellent thermal stability and chemical stability. However, PTFE nanofiber membranes with simultaneous hydrophobic and oleophobic properties are essential to promote the application of PTFE. Here, based on inorganic/organic nanohybridization, we report a strategy for constructing nanostructures on fibers by adding nanoparticles, such as MOF and ZrO2. The results of FTIR and XRD confirmed MOF was synthesized successfully. At the same time, the SEM results showed UiO-66-(COOH)2 is spherical with an average diameter of 152 nm, and there is no agglomeration, which is suitable for electrospinning. Further, MOF and ZrO2 were payload into PTFE nanofibers. The results of SEM and AFM confirmed nanostructures will be more uniform and pronounced with the increase of UiO-66-(COOH)2 content, and nanostructures are most obvious when the content of UiO-66-(COOH)2 is 15%. The introduced nanostructures can increase the oil contact angle of the PTFE nano-porous membrane to 110° without introducing other groups, and further improve the water contact angle from 133° to 145°. Meanwhile, the introduction of a certain amount of hydrophilia groups can increase the oil contact angle to more than 120°. The simple strategy is of great significance to expand the application of PTFE fiber membrane in dealing with waste water treatment fields.

Segmental Quantitative MR Imaging Analysis of Diurnal Variation of Water Content in the Lumbar Intervertebral Discs

Tingting Zhu,Tao Ai,Wei Zhang,Tao Li,Xiaoming Li 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.1

To investigate the changes in water content in the lumbar intervertebral discs by quantitative T2 MR imaging in the morning after bed rest and evening after a diurnal load. Twenty healthy volunteers were separately examined in the morning after bed rest and in the evening after finishing daily work. T2-mapping images were obtained and analyzed. An equally-sized rectangular region of interest (ROI) was manually placed in both, the anterior and the posterior annulus fibrosus (AF), in the outermost 20% of the disc. Three ROIs were placed in the space defined as the nucleus pulposus (NP). Repeated-measures analysis of variance and paired 2-tailed t tests were used for statistical analysis, with p < 0.05 as significantly different. T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001). Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001). T2 values in the posterior AF showed the largest degree of variation among the 5 ROIs, but there was no statistical significance (p = 0.414). Discs with initially low T2 values in the center NP showed a smaller degree of variation in the anterior NP and in the central NP, than in discs with initially high T2 values in the center NP (10.0% vs. 16.1%, p = 0.037; 6.4% vs. 16.1%, p = 0.006, respectively). Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

Subproteomic profiling from renal cortices in OLETF rats reveals mutations of multiple novel genes in diabetic nephropathy

Li Zhiguo,Shen Hong,Liu Yeqiang,Zhou Xuefeng,Yan Meihua,He Hailan,Zhao Tingting,Zhang Haojun,Li Ping 한국유전학회 2022 Genes & Genomics Vol.44 No.1

Background: Ovarian cancer is a common gynecological malignancy among female patients and poses a serious threat to women's health. Although it has been established that Fos-like antigen 2 (FOSL2) is linked to ovarian cancer (OC), its exact role in the development of OC remains unknown. Objective: This article aims to investigate the role of FOSL2 in ovarian cancer development. Methods: FOSL2 expression in ovarian carcinoma and adjacent tissues was assessed using real-time fluorescent quantitative PCR and western blot. We constructed OE/sh-FOSL2 plasmids and Caspase-1 specific inhibitors (Yvad-CMK) and transfected A 2780 cells with them to identify the relevant cell functions. Furthermore, we used western blot assay to determine the changes in expression of apoptosis-associated speck-like protein containing a CARD (ASC), cysteine aspartate-specific proteasezymogen procaspase 1 (pro-caspase-1), cysteinyl aspartate-specific proteinase-1 (caspase-1), interleukin-1β precursor (pro-IL-1β), interleukin-1β (IL-1β), interleukin-18 precursor (pro-IL-18), and interleukin-18 (IL-18). In addition, we measured the concentration of IL-1β and IL-18 using an enzyme-linked immunosorbent assay (ELISA). Moreover, Tthe level of lactate dehydrogenase (LDH) in the cell supernatant was measured by LDH release assay kit. Results: The expression of FOSL2 was significantly higher compared with the surrounding tissues. The proliferation, migration, and invasion of A2780 cells were enhanced after transfection with OE-FOSL2 plasmids; however, the cell apoptosis was significantly decreased. When FOSL2 was overexpressed, the inflammasome-associated proteins such as ASC, caspase-1, IL-1β, and IL-18 were downregulated. Furthermore, FOSL2 induced apoptosis and activated the production of inflammasomes in A2780 cells. Co-therapy with Yvad-CMK and substantially inhibited apoptosis and activation of inflammasomes. Conclusions: Inhibition of FOSL2 promotes the apoptosis of OC cells by mediating the formation of an inflammasome.

Apoptosis induction by alantolactone in breast cancer MDA-MB- 231 cells through reactive oxygen species-mediated mitochondrion-dependent pathway

Li Cui,Weiquan Bu,Jie Song,Liang Feng,Tingting Xu,Dan Liu,Wenbo Ding,Jianhua Wang,Changyang Li,Binge Ma,Yi Luo,Ziyu Jiang,Chengcheng Wang,Juan Chen,Jian Hou,Hong-mei Yan,Lei Yang,Xiao-bin Jia 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.3

Alantolactone is a sesquiterpene lactone isolatedfrom Inula helenium L. Although alantolactone possessesanti-inflammation and apoptosis-induction activities, theunderlying mechanism of anti-cancer effect on humanbreast cancer cells remains largely unknown. In this study,we explored the possibility of alantolactone as an apoptosis-inducing cytotoxic agent using MDA-MB-231 cells asin vitro model. Alantolactone significantly induced itsapoptosis, demonstrated by cell cycle analysis, annexinV-APC/7-AAD double staining and dUTP nick end labeling. Additionally, alantolactone triggered the mitochondrial-mediated caspase cascade apoptotic pathway, whichwas confirmed by increased Bax/Bcl-2 ratio, loss of MMP,release of cytc from mitochondria to cytoplasm, activationof caspase 9/3, and subsequent cleavage of PARP. Z-VADFMKpartially prevented apoptosis induced by alantolactone. Alantolactone provoked the production of ROS, whileNAC (a scavenger of ROS) reversed alantolactone-mediateddepolarization of MMP and apoptosis. Alantolactonemodulated the activities of MAPKs. As expected, cotreatmentwith SB203580, SP600125 or U0126 could reducedthe apoptotic rate. Furthermore, alantolactone decreasedthe protein expressions of p-NF-kB p65 and p-STAT3,increased p-c-Jun level in a dose-dependent manner. Thesefindings suggested that alantolactone possessed anticanceractivity via ROS-mediated mitochondrial dysfunctioninvolving MAPK pathway, and had an effect on the transcriptionfactors of NF-kB, AP-1 and STAT3.

Screening of Antioxidant and Antitumor Activities of Major Ingredients from Defatted Camellia oleifera Seeds

Tingting Li,Hui Zhang,Cai-e Wu 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.3

Three major ingredients (saponin, protein, andpolysaccharide) were obtained from defatted Camelliaoleifera Abel seeds by sequential extraction. A series ofexperiments were conducted to compare the antioxidantand antitumor activities of these three major ingredients. The antioxidant activities of these ingredients were evaluatedby reducing power, hydroxyl, superoxide anion, and DPPHradical scavenging assays. All antioxidant tests showedthat the protein had the highest antioxidant activity amongthe three samples, and the antioxidant effects of proteinincreased in a dose-dependent manner. In vitro, the antitumoractivities of the three major ingredients against Hep G2cells at different concentrations were examined by MTTassay. The polysaccharide exhibited the highest potencyagainst Hep G2 cells, with an IC50 value of 5.826 μg/mL,followed by saponin (26.754 μg/mL). These findings suggestthat the protein and polysaccharide from defatted C. oleifera seeds exhibit significant antioxidant and antitumoractivities, respectively, which deserve further research.

Transit ridership models considering endogeneity and heteroscedasticity in a big data

LI TINGTING 한국ITS학회 2017 한국ITS학회 학술대회 Vol.2017 No.04