Iron-doped chitosan microsphere for As(III) adsorption in aqueous solution: Kinetic, isotherm and thermodynamic studies

Xiaoyu Lin,Leli Wang,Shi Jiang,Longzhe Cui,Gui-Ping Wu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.7

Iron-doped chitosan microsphere was prepared successfully and employed for effective adsorption of As(III). The results showed that the adsorption capacity benefited from the increase of iron content, and the maximum adsorption capacity was achieved at pH=8. According to the study of adsorption kinetics, adsorption rate was controlled by liquid film diffusion at a lower rotational speed, while it was controlled by chemical reaction rate at a higher rotational speed. The Freundlich and Temkin models exhibited a better fit to adsorption isotherm data, which indicated the adsorption of As(III) on iron-doped chitosan microsphere was chemisorption and the active sites of adsorbents were non-uniform distributed. Adsorption process was a spontaneous exothermic reaction because its ΔG and ΔH were negative. In presence of cations (Cd2+, Pb2+ or Zn2+) in solution, the iron-doped chitosan microsphere also showed the significant removal of As(III). However, the existence of anions (NO3 , SO4 2 or PO4 3) inhibited the As(III) removal at different level. PO4 3 showed the most significant side effects on the removal of As(III) by iron-doped chitosan microsphere. The used iron-doped chitosan adsorbent can be effectively regenerated using 1.0mol·L1 NaOH solution, and the adsorption efficiency decreased only 15.69% after being reused three times. The results of XPS, FT-IR showed that the adsorption was mainly achieved by the coordination interaction between As (III) and doped Fe in adsorbent.

Sequential recovery of copper, silver, and gold from waste electrical and electronic equipment based on leaching and adsorption

( Xiaoyu Lin ),( Duy Tho Tran ),( Myung-hee Song ),( Yeoung-sang Yun ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

It is important to separate and recover valuable metals from waste electrical and electronic equipments (WEEEs). Here, a new strategy for leaching-adsorption sequential leaching-recovery of copper, silver, and gold from WEEEs was presented. Firstly, a leaching efficiency of 99.9% copper was achieved using a mixture of sulfuric acid (0.45%) and hydrogen peroxide (5%). Subsequently, chitosan fibers (CFs) were prepared and used for the recovery of Cu(II), showing that its adsorption efficiency was 97.85 ± 0.02% within 30 min. The Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the adsorption mechanism is likely a coordination bond between Cu(II) and amino groups of CFs. During the copper recovery process, sulfate (SO₄^2-) in the leachate was also removed by CFs with an efficiency of 98.79 ± 1.67%, which was via an electrostatic attraction. Next, silver was leached with a nitric acid solution, and then silver chloride was recovered using sodium chloride. The leaching and recovery of Ag were approximately 100%. Finally, gold was leached with cyanide as low as 50 ppm at pH around 10.5, resulting in its leaching efficiency of 90.75 ± 3.45%. The leached gold was recovered with 96.21 ± 2.96% efficiency by quaternary amino-functionalized chitosan fibers (QCFs) within 5 mins. Gold species in the leachate was confirmed to be gold cyanide anions (Au(CN)₂^-). The XPS analysis indicated that the electrostatic attraction between quaternary amine groups in QCFs and Au(CN)₂^- play a major role in gold adsorption . Metallic gold with a purity of 97.4% was obtained by incineration of gold-loaded QCFs.

Pseudolaric Acid B Inhibits Proliferation, Invasion and Epithelial-to-Mesenchymal Transition in Human Pancreatic Cancer Cell

Xiaoyu Li,Xianzhi Zhao,Wen Song,Zibin Tian,Lin Yang,Qinghui Niu,Qi Zhang,Man Xie,Bin Zhou,Yonghong Xu,Jun Wu,Cuiping Zhang 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.1

Purpose: This study was aimed to investigate the effect of pseudolaric acid B (PAB) on proliferation, invasion and epithelial-to-mesenchymal transition (EMT) in pancreatic cancer cells and to explore the possible mechanism. Materials and Methods: The pancreatic cancer cell line SW1990 was cultured and treated with PAB dose- and time-dependent manners. Cell proliferation and invasion ability were measured by MTT assay and Matrigel/Transwell test, respectively. Semi-quantitative real-time polymerase chain reaction and Western blotting were conducted to detect the expression of EMT markers and the key molecules. Finally, nude mice subcutaneous transplantation tumor model was used to confirm the therapy efficacy of PAB. Results: PAB could inhibit SW1990 cell proliferation and invasion in time- and dose-dependent manners. Vimentin, fibronectin, N-cadherin, Snail, Slug, YAP, TEAD1, and Survivin were down-regulated (p<0.01), while E-cadherin, caspase-9, MST1, and pYAP were up-regulated (p<0.05). Combined PAB and gemcitabine treatment markedly restricted the tumor growth compared with gencitabin or PAB alone groups. Conclusion: PAB could inhibit the proliferation and invasion ability of pancreatic cancer cells through activating Hippo-YAP pathway and inhibiting the process of EMT.

A High Power Density and Efficiency Bi-Directional DC/DC Converter for Electric Vehicles

Xiaoyu Jia,Dehong Xu,Shuailin Du,Changsheng Hu,Min Chen,Ping Lin 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In electric vehicle systems, bi-directional DC/DC converters are used to interface the battery bank with the high voltage DC bus of the inverter. The high power density and high efficiency are required for bidirectional DC/DC converters. This paper discusses the relationship between switching frequency, inductor value and passive components volume. First, the topologies of the system and the converter are presented. Then, the loss breakdown model is provided. A selection for the switching frequency is presented and an option of inductor value is provided to reduce the converter size and to keep the converter efficient. Then the converter layout which further enhances the power density is discussed. Finally, a high power density and high efficiency converter prototype is built, and the efficiency and thermal performance evaluation of the converter at different operating conditions is given.

Factors Associated with Behaviors Toward End-of-life Care Among Chinese Oncology Nurses: A Cross-Sectional Study

Xiaoyu Wu,Zhihuan Zhou,Yiheng Zhang,Xiaoyan Lin,Meng Zhang,Fulin Pu,Meifen Zhang 한국간호과학회 2021 Asian Nursing Research Vol.15 No.5

Purpose The goal of this study was to describe the current status of oncology nurses' behaviors toward end of life (EOL) care in China and to explore the factors associated with oncology nurses’ behaviors toward EOL care. Methods A cross-sectional design was applied and a convenience sample of 1038 oncology nurses from 22 grade A hospitals were recruited into this study. A general social demographic data questionnaire was administered, and the Chinese version of Nurses’ Behaviors of Caring for Dying Patients Scale was used to assess nurse behavior toward EOL care. The total score ranges from 40 to 200 points. Data were analyzed with SPSS 26.0 software. Results Chinese oncology nurses' average score of holistic EOL care behaviors was 2.97 ± 0.59. Oncology nurses provide physical care most (3.81 ± 0.76), followed by family care (3.02 ± 0.86), and spiritual care (2.37 ± 0.67). Multiple regression analysis showed that a higher frequency of sharing EOL care experience with colleagues, in-service palliative care education, higher level of head nurse support for EOL patient care, more cases of EOL care, higher working position, and nurse's perceived high level of support were positively associated with behavior toward EOL care. These six factors explained 16.2% of the total variance. Conclusions The results may help provide a basis for converting behavior for EOL care among oncology nurses and design interventions to better improve quality of life for EOL patients with cancer in China. Purpose The goal of this study was to describe the current status of oncology nurses' behaviors toward end of life (EOL) care in China and to explore the factors associated with oncology nurses’ behaviors toward EOL care. Methods A cross-sectional design was applied and a convenience sample of 1038 oncology nurses from 22 grade A hospitals were recruited into this study. A general social demographic data questionnaire was administered, and the Chinese version of Nurses’ Behaviors of Caring for Dying Patients Scale was used to assess nurse behavior toward EOL care. The total score ranges from 40 to 200 points. Data were analyzed with SPSS 26.0 software. Results Chinese oncology nurses' average score of holistic EOL care behaviors was 2.97 ± 0.59. Oncology nurses provide physical care most (3.81 ± 0.76), followed by family care (3.02 ± 0.86), and spiritual care (2.37 ± 0.67). Multiple regression analysis showed that a higher frequency of sharing EOL care experience with colleagues, in-service palliative care education, higher level of head nurse support for EOL patient care, more cases of EOL care, higher working position, and nurse's perceived high level of support were positively associated with behavior toward EOL care. These six factors explained 16.2% of the total variance. Conclusions The results may help provide a basis for converting behavior for EOL care among oncology nurses and design interventions to better improve quality of life for EOL patients with cancer in China.

SOS Based Robust Control for Dynamic Positioning System Subject to Actuator Saturation

Xiaoyu Su,Bin Lin 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

In this paper, the problem of thruster saturation is considered for dynamic positioning systems of offshore platforms, specifically, a state feedback controller is developed for polynomial systems subject to actuator saturation. The sufficient conditions of stabilization problem are formulated in the form of sum of squares to ensure the desired H infinity performance, which can be numerically solved via the SOSTOOLS.For the modeling uncertainty problem caused by the uncertain hydrodynamic parameter, the results are extended to the uncertain system for the consideration of wider applications. Finally, simulations are conducted for a system with parameter uncertainties and thrust saturation in dynamic positioning system to illustrate the effectiveness and advantages of the proposed control strategy.

Fault-tolerant Controller Design for Active Suspension System with Proportional Differential Sliding Mode Observer

Bin Lin,Xiaoyu Su 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.7

This paper proposes a fault-tolerant control scheme for the quarter active suspension systems with uncertainties and nonlinear. First, by the generalized augmented transformation, state variables, actuator faults, sensorfaults and external disturbances are converted to the augmented states then the subsequent calculation becomessimple. Second, on the basis of the generalized augmented system, a new sliding mode observer with proportional terms and differential terms is designed for state estimation and fault reconstruction. In order to improve theride comfort and operation stability of the automobile in an all-round way, a fault-tolerant controller is designedfor active suspension system. The simulations are conducted to illustrate the effectiveness and advantages of thisproposed observer and control strategy.

Hydrothermal Synthesis and Photocatalytic Performance of Ag Quantum Dots Sensitized Bi4Ti3O12 Nanobelts

Xue Lin,Xiaoyu Guo,Di Liu,Qingwei Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.2

Ag/Bi4Ti3O12 heterostructure with high photocatalytic activity was synthesized via a simple and practical hydrothermal method by using Bi4Ti3O12 nanobelts as substrate materials. The as-prepared Ag/Bi4Ti3O12 heterostructure included Ag quantum dots assembling uniformly on the surface of Bi4Ti3O12 nanobelts. Comparing with pure Bi4Ti3O12 nanobelts, the composite photocatalyst exhibited enhanced photocatalytic activity under visible light irradiation in the decomposition of rhodamine B aqueous solution. The enhancement performance is believed to be induced by the intimate contact interface, where silver quantum dots serve as good electron acceptor for facilitating quick photoexcited electron transfer and thus decreasing electron-hole recombination. It was also found that the photodegradation of rhodamine B molecules is mainly attributed to the oxidation action of the generated O2 radicals.

Molecular characterization of duck enteritis virus CHv strain UL49.5 protein and its colocalization with glycoprotein M

Meng Lin,Renyong Jia,Mingshu Wang,Xinghong Gao,Dekang Zhu,Shun Chen,Mafeng Liu,Zhongqiong Yin,Yin Wang,Xiaoyue Chen,Anchun Cheng 대한수의학회 2014 JOURNAL OF VETERINARY SCIENCE Vol.15 No.3

The UL49.5 gene of most herpesviruses is conserved andencodes glycoprotein N. However, the UL49.5 protein ofduck enteritis virus (DEV) (pUL49.5) has not been reported. In the current study, the DEV pUL49.5 gene was firstsubjected to molecular characterization. To verify thepredicted intracellular localization of gene expression, therecombinant plasmid pEGFP-C1/pUL49.5 was constructedand used to transfect duck embryo fibroblasts. Next, therecombinant plasmid pDsRed1-N1/ glycoprotein M (gM)was produced and used for co-transfection with thepEGFP-C1/pUL49.5 plasmid to determine whether DEVpUL49.5 and gM (a conserved protein in herpesviruses)colocalize. DEV pUL49.5 was thought to be an envelopeglycoprotein with a signal peptide and two transmembranedomains. This protein was also predicted to localize in thecytoplasm and endoplasmic reticulum with a probability of66.7%. Images taken by a fluorescence microscope atdifferent time points revealed that the DEV pUL49.5 andgM proteins were both expressed in the cytoplasm. Overlapof the two different fluorescence signals appeared 12 h aftertransfection and continued to persist until the end of theexperiment. These data indicate a possible interaction between DEV pUL49.5 and gM.

Integration of hemicellulose pre-extraction and solid alkali-oxygen cooking processes for lignocellulose fractionation with emphasis on xylan valorization

Yetao Jiang,Xiaoyu Wang,Zhen Wu,Jiaxing Xu,Lei Hu,Lu Lin 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.4

Cooking with active oxygen and solid alkali (CAOSA) is a mild and environmentally friendly method for separation of lignin components. The degradation mechanism of hemicellulose associated with this method has been investigated. It was found that the hemicellulose-derived polysaccharides were directly oxidized rather than hydrolyzed to monosaccharides for degradation. To avoid the undesirable degradation of hemicellulose components by CAOSA, the idea of separating hemicellulose first in the form of xylan to produce xylooligosaccharide was presented by this study. Although hydrothermal autocatalysis has been commonly used in hemicellulose separation, the effects of acidenhanced hydrothermal method and alkali-suppressed hydrothermal method on hydrothermal autocatalysis were systematically compared for the first time, and it was found that the acid-enhanced method was beneficial for highly selective extraction of xylan. Then, the hemicellulose-removed bamboo was treated with CAOSA process to separate lignin from cellulose. It was found that solid alkali dosage of CAOSA could be evidently decreased for hemicelluloseremoved bamboo, which was helpful to reduce the cost of CAOSA. Coupling hemicellulose pre-extraction and CAOSA lignin fractionation strategy, a comprehensive biorefinery case for bamboo biomass could be anticipated.