Capacitive deionization of saline water using sandwich-like nitrogen-doped graphene composites <i>via</i> a self-assembling strategy

Yan, Tingting,Liu, Juan,Lei, Hong,Shi, Liyi,An, Zhongxun,Park, Ho Seok,Zhang, Dengsong The Royal Society of Chemistry 2018 Environmental science Vol.5 No.11

<P>Capacitive deionization (CDI) is a promising water treatment technology that is proposed to solve water scarcity. In this study, sandwich-like nitrogen-doped graphene composites were designed and produced as high-performance CDI electrodes <I>via</I> a self-assembling strategy. Nitrogen-doped mesoporous carbon was directly created and assembled onto the graphene surface using dopamine hydrochloride as a carbon and nitrogen source and nano-silica as a hard template. This unique sandwich architecture provides a large accessible surface area and lower electronic resistivity, resulting from creating a “plane-to-porous plane” conducting network for increased adsorption sites and rapid electron transportation pathways. The specific surface area (918 m<SUP>2</SUP> g<SUP>−1</SUP>) and excellent wettability of sandwich-like nitrogen-doped graphene were further improved by incorporating nitrogen in surface texture and chemistry. The material was tested for the CDI application in NaCl aqueous solution. The sandwich-like nitrogen-doped graphene electrodes demonstrated a high salt adsorption capacity of up to 18.4 mg g<SUP>−1</SUP> in a 500 mg L<SUP>−1</SUP> NaCl aqueous solution with a larger charge efficiency and an ideal recycling performance. These enhanced capacitive deionization performances of the sandwich-like nitrogen-doped graphene electrodes are attributed to the unique “plane-to-porous plane” internetworked architecture. This study offers a promising solution to develop high-performance electrode materials for removal of ions from saline water.</P>

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.

EXPERIMENTAL STUDY OF PARTICULATE EMISSION CHARACTERISTICS FROM A GASOLINE DIRECT INJECTION ENGINE DURING STARTING PROCESS

Yan Su,Fangxi Xie,Wei Hong,Xiaoping Li,Tingting Hu 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.2

The engine starting process presents high particulate emissions in exhaust. This study gives a systematic investigation on particulate emission characteristics, including particulate matter (PM) mass, soluble organic fraction (SOF) mass, C10-C26 n-Alkanes and particle-bound polycyclic aromatic hydrocarbons (PAHs), that have been emitted from a gasoline direct injection (GDI) engine measured by Gas chromatography–mass spectrometry during starting period. The results show that particulate emissions under the warm coolant start condition decline dramatically compared with the cold start condition. 90 % of particulate number (PN) emitted during the cold and warm start periods generally are nucleation-mode particles. Over 50 % PM mass and PAHs emissions are emitted in the first 0−13 s stage. SOF mass accounts more than 60 % in PM mass emissions, especially under the warm coolant start condition. Some C23-C26 n-Alkanes are detected under the cold start condition which demonstrates that partial particulate composition directly comes from lubricant. The concentration of the two ring PAHs is the lowest among PAHs while the four to six ring PAHs are higher under the cold start operation. The toxicity of PAHs which is evaluated by Benzo(a)pyrene equivalent toxicity (BEQ) value of the total PAHs emissions shows a decline of 66.83 % under the warm start condition.

Delay-dependent Stability Criteria for Linear Systems with Two Additive Time-varying Delays

Yan Li,Tingting Qiu,Yuehai Yang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.2

This paper studies the stability problem of linear systems with two additive time-varying delays. Firstly, a modified Lyapunov-Krasovskii functional (LKF) is constructed involving the delay-dependent non-integral items and some augmented single-integral items. Secondly, based on the improved LKF, a stability criterion is derived via the generalized free-matrix-based inequality application, which is less conservative than some recent existing ones. Thirdly, a generalized refinement of allowable delay set removed some impossible delay subsets is proposed to further reduce the conservatism of the stability criterion. Finally, a numerical example and an application of the load frequency control for a single area power system are presented to show the effectiveness of the proposed approach.

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.

An Unambiguous Deterministic Compressed Acquisition Technique for BOC Signal

Xiaoheng Tan,Yan Zhang,Qiang Yan,Tingting Pan,Xiaonan Hu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

The long PN code in a Binary Offset Carrier (BOC) modulated signal has a higher rate than the GPS C/A code, which makes the acquisition process in the new global navigation satellite system (GNSS) much more complex. To achieve a fast acquisition of the GNSS signal with a reduced number of correlators and low computational complexity, a two-stage deterministic compressed (DS) GNSS acquisition technique has been proposed. Nevertheless, the ambiguous threat of BOC signal isn’t taken into account in the DS technique. To eliminate the ambiguity threat in the acquisition process of BOC (m, n) signal, an unambiguous deterministic compressed acquisition is proposed in this paper. The main idea of the proposed technique is to introduce a simplified GRASS algorithm in the second stage measurement. Theoretical analysis and simulation results show that, at the expense of some performance degradation the proposed technique can completely remove the undesired positive side peaks of BOC (m, n) signal, and reduce the chance of false peak acquisition compared with the DS technique.

Norepinephrine/β2-Adrenergic Receptor Pathway Promotes the Cell Proliferation and Nerve Growth Factor Production in Triple-Negative Breast Cancer

Meihua Jin,Yan Wang,Tingting Zhou,Wenzhe Li,Qingping Wen 한국유방암학회 2023 Journal of breast cancer Vol.26 No.3

Purpose: Invasive ductal carcinoma (IDC) accounts for 90% of triple-negative breast cancer (TNBC). IDC is mainly derived from the breast ductal epithelium which is innervated by the 4th to 6th thoracic sympathetic nerves. However, little is known about the contribution of the interactions between sympathetic nerves and breast cancer cells to the malignant progression of TNBC. Methods: The expression levels of the β2-adrenergic receptor (β2-AR, encoded by ADRB2 gene), nerve growth factor (NGF), and tropomyosin receptor kinase A (TrkA) were determined using immunohistochemistry (IHC). NGF expression levels in the serum were compared by enzyme-linked immunosorbent assay (ELISA). Cell proliferation was assessed using the Cell Counting Kit-8 assay. The β2-AR, NGF, p-ERK, and p-CERB expression levels were determined using western blotting. TNBC cells and neuronal cells of the dorsal root ganglion (DRG) in 2-day-old Sprague Dawley rats were co-cultured. Using norepinephrine (NE), NGF, and β2-AR, NGF/TrkA blocker pretreatments, the axon growth of each group of DRG neuron cells was detected by immunofluorescence analysis. Results: The sympathetic adrenergic neurotransmitter NE activated the ERK signaling pathway in TNBC cells. NE/β2-AR signaling promotes NGF secretion. NGF further facilitates the malignant progression of TNBC by increasing sympathetic neurogenesis. In the co-culture assay, the sympathetic adrenergic NE/β2-AR signal pathway also enhanced NGF secretion. NGF binds TrkA in DRG neurons and promotes axonal growth. Conclusion: These results suggest that NE/β2-AR pathway promotes cell proliferation and NGF production in triple-negative breast cancer.

Physicochemical stability and antibacterial mechanism of theabrownins prepared from tea polyphenols catalyzed by polyphenol oxidase and peroxidase

Xiaoqiang Chen,Tingting Chen,Jiayan Liu,Yan’an Wei,Weilong Zhou 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.1

Tea polyphenols were used as substrates and oxidized successively by polyphenol oxidase and peroxidase to prepare theabrownins (TBs-dE). The conversion rate of catechins to TBs-dE was 90.91%. The ultraviolet and infrared spectroscopic properties and zeta potential of TBs-dE were characterized. TBs-dE is more stable at pH 5.0–7.0, about 25 °C or in dark environment. Ultraviolet light and sunlight can deepen its color due to the further oxidative polymerization. Mg2+, Cu2+, and Al3+ had a significant effect on the stability of TBs-dE. The inhibitory rates of TBs-dE (1 mg/mL) against Staphylococcus aureus and Escherichia coli DH5α were 51.45% and 45.05%, respectively. After TBs-dE treatment, the cell morphology of both bacteria changed, some cell walls were blurred, and the cytoplasmic content leaked. The research results can provide theoretical support for the industrialization of theabrownins.

Comparison of image masking methods for pump impeller blade region PIV experiments

Xiaodong Liu,Tingting Yan,Qiang Zhong,Zhuqing Liu,Fujun Wang,Yaojun Li,Wei Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Due to the blade reflection effect when applying the PIV technology to the internal flow field measurement of rotating machinery, the blade area requires special treatment. In this paper, zero-value, particle image, random number, and mean-value masking methods are compared and analyzed based on particle images from the PIV challenge and rotating impeller. The peak significance and coordinates deviations are used as the masking effect evaluation criteria. The results indicate that an increase in the interrogation window masking area proportion causes a weakening of the PIV calculation particle cluster displacement peak value. The peak position is shifted, which leads to the wrong velocity vector. The masking area proportion should not be higher than 0.7, 0.5, 0.19, and 0.22 for mean-value, random number, zero-value, and particle image masking methods, respectively. The results show that flow field calculation results near the blade boundary are more accurate for mean-value masking.

Molecular cloning, characterization, and functional analysis of a gene encoding 3-hydroxy-3-methylglutaryl-coenzyme A synthase from Matricaria chamomilla

Feng Xu,Tingting Tao,Qiangwen Chen,Xiangxiang Meng,Jiaping Yan,Jie Chang 한국유전학회 2016 Genes & Genomics Vol.38 No.12

3-Hydroxy-3-methylglutaryl-CoA synthase (HMGS) catalyzes the condensation of acetyl-CoA and acetoacetyl- CoA to form 3-hydroxy-3-methylglutaryl-CoA as the first committed enzyme in the mevalonate (MVA) pathway. HMGS plays an important role in the biosynthesis of the sesquiterpene, which is the main constituent of essential oil in Matricaria chamomilla. In this paper, a HMGS gene designated as McHMGS (GenBank Accession No. KU529970) was successfully cloned from M. chamomilla. The full-length cDNA of McHMGS was 1495-bp and contained a 1374-bp open reading frame. It encoded a 458-amino-acid protein with a calculated molecular weight of about 50.7 kDa and isoelectric point of 5.69. Sequence comparison revealed that McHMGS showed extensive homology with HMGSs from other plant species. Phylogenetic tree analysis indicated that McHMGS is clustered with the HMGS of Asteraceae in the dicotyledoneae clade. Further functional complementation of McHMGS in hmgsdeficient mutant yeast strain YSC6274 demonstrated that cloned McHMGS cDNA encodes a functional HMGS and mediates the MVA biosynthesis in yeasts. The tissue expression pattern analysis revealed that McHMGS expression level is highest in the flowers and lowest in the stems. Quantitative real-time PCR analysis showed that the expression of McHMGS was induced by MeJA, and the expression level is highest 24 h after induction. The characterization and expression of McHMGS can help in further studying the role of McHMGS gene in the biosynthesis of sesquiterpene in M. chamomilla.