Multiscale Prototyping Approach via In-situ Switching Electrohydrodynamics for Flexible Microfluidic Design

Jiawen Xu,Haodong Hong,Zhenyu Wang,Xinhu Sun,Yen Wei,Yu Liu 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.11 No.2

Microfluidic devices are critical in lab-on-chip, drug delivery, flexible sensors, etc. However, a formidable challenge remains in fabricating microfluidic channels with complex shapes during design and verification. Herein, we present a facile approach for manufacturing polystyrene (PS) templates by in-suit combining microscale electrohydrodynamic (EHD) printing and mesoscale direct ink writing (DIW). The desired multiscale filament width from 20 μm to > 1 mm could be obtained through appropriate voltage and pressure with continuous printing. The further process parameters for adjusting line width including deposition speed, auxiliary heating for DIW/EHD printing mode were investigated detailly. And we prove the stability and feasibility for producing microfluidics via the method by AFM, EDS and filling test. Based on the solubility of PS in the organic solvent, we can readily reconfigure the existing template by erasing and printing part of the patterns for better remanufacturing. Finally, the LM-filling PDMS microfluidic is experimented to demonstrate the future potential and advantage of the printing technology for fabricating the flexible microfluidic device.

Study on the influence of Alpha wave music on working memory based on EEG

Xin Xu,Jiawen Sun 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.2

Working memory (WM), which plays a vital role in daily activities, is a memory system that temporarily stores and processes information when people are engaged in complex cognitive activities. The influence of music on WM has been widely studied. In this work, we conducted a series of n-back memory experiments with different task difficulties and multiple trials on 14 subjects under the condition of no music and Alpha wave leading music. The analysis of behavioral data show that the change of music condition has significant effect on the accuracy and time of memory reaction (p<0.01), both of which are improved after the stimulation of Alpha wave music. Behavioral results also suggest that short-term training has no significant impact on working memory. In the further analysis of electrophysiology (EEG) data recorded in the experiment, auto-regressive (AR) model is employed to extract features, after which an average classification accuracy of 82.9% is achieved with support vector machine (SVM) classifier in distinguishing between before and after WM enhancement. The above findings indicate that Alpha wave leading music can improve WM, and the combination of AR model and SVM classifier is effective in detecting the brain activity changes resulting from music stimulation.

Changes in Gene Expression of Actinobacillus pleuropneumoniae in Response to Anaerobic Stress Reveal Induction of Central Metabolism and Biofilm Formation

Lu Li,Jiawen Zhu,Kui Yang,Zhuofei Xu,Ziduo Liu,Rui Zhou 한국미생물학회 2014 The journal of microbiology Vol.52 No.6

Actinobacillus pleuropneumoniae is an important porcinerespiratory pathogen causing great economic losses in thepig industry worldwide. Oxygen deprivation is a stress thatA. pleuropneumoniae will encounter during both early infectionand the later, persistent stage. To understand modulationof A. pleuropneumoniae gene expression in responseto the stress caused by anaerobic conditions, gene expressionprofiles under anaerobic and aerobic conditions werecompared in this study. The microarray results showed that631 genes (27.7% of the total ORFs) were differentially expressedin anaerobic conditions. Many genes encoding proteinsinvolved in glycolysis, carbon source uptake systems,pyruvate metabolism, fermentation and the electron respirationtransport chain were up-regulated. These changes ledto an increased amount of pyruvate, lactate, ethanol and acetatein the bacterial cells as confirmed by metabolite detection. Genes encoding proteins involved in cell surface structures,especially biofilm formation, peptidoglycan biosynthesisand lipopolysaccharide biosynthesis were up-regulatedas well. Biofilm formation was significantly enhancedunder anaerobic conditions. These results indicate that inductionof central metabolism is important for basic survivalof A. pleuropneumoniae after a shift to an anaerobic environment. Enhanced biofilm formation may contribute tothe persistence of this pathogen in the damaged anaerobichost tissue and also in the early colonization stage. Thesediscoveries give new insights into adaptation mechanismsof A. pleuropneumoniae in response to environmental stress.

The role of layered double hydroxides shell in enhancing the adsorption capacity of NaY zeolite for toluene in wet conditions

Yanyao Li,Tao Yin,Jiawen Xu,Naiwang Liu,Li Shi,Xuan Meng 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.5

Surface modification of zeolite is known to enhance its adsorption capacity for volatile organic compounds (VOCs). In this study, a hydrophobic adsorbent, NaY@LDHs, with layered double hydroxides (LDHs) as the shell and NaY zeolite as the core, was successfully synthesized. It was found that treating LDHs with ethanol can result in a larger specific surface area and pore volume, enhancing the adsorption performance of toluene under wet conditions. SEM imaging reveals that the LDHs shell grows vertically on the surface of the NaY zeolite. The dynamic adsorption experiment of toluene showed that under humid conditions, NaY@LDHs exhibited a saturated adsorption capacity of 32.42 mg/g, representing a significant 87% increase compared to the parent NaY zeolite. The kinetic results show that the adsorption of toluene on NaY@LDHs is primarily physical adsorption, and other factors influence the adsorption process in addition to intraparticle diffusion. Therefore, the air layer formed by the LDHs shell on the surface of NaY zeolite imparts a hydrophobic effect, making NaY@LDHs a promising material for adsorbing volatile organic compounds in a wet environment.

Identification of drug target candidates of the swine pathogen Actinobacillus pleuropneumoniae by construction of protein–protein interaction network

Siqi Li,Zhipeng Su,Chengjun Zhang,Zhuofei Xu,Xiaoping Chang,Jiawen Zhu,Ran Xiao,Lu Li,Rui Zhou 한국유전학회 2018 Genes & Genomics Vol.40 No.8

Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae has led to severe economic losses in the pig industry worldwide. A. pleuropneumoniae displays various levels of antimicrobial resistance, leading to the dire need to identify new drug targets. Protein–protein interaction (PPI) network can aid the identification of drug targets by discovering essential proteins during the life of bacteria. The aim of this study is to identify drug target candidates of A. pleuropneumoniae from essential proteins in PPI network. The homologous protein mapping method (HPM) was utilized to construct A. pleuropneumoniae PPI network. Afterwards, the subnetwork centered with H-NS was selected to verify the PPI network using bacterial two-hybrid assays. Drug target candidates were identified from the hub proteins by analyzing the topology of the network using interaction degree and homologous comparison with the pig proteome. An A. pleuropneumoniae PPI network containing 2737 non-redundant interaction pairs among 533 proteins was constructed. These proteins were distributed in 21 COG functional categories and 28 KEGG metabolic pathways. The A. pleuropneumoniae PPI network was scale free and the similar topological tendencies were found when compared with other bacteria PPI network. Furthermore, 56.3% of the H-NS subnetwork interactions were validated. 57 highly connected proteins (hub proteins) were identified from the A. pleuropneumoniae PPI network. Finally, 9 potential drug targets were identified from the hub proteins, with no homologs in swine. This study provides drug target candidates, which are promising for further investigations to explore lead compounds against A. pleuropneumoniae.

Identification, sequence analysis, and infectivity of H9N2 avian influenza viruses isolated from geese

Rui Zhu,Xueqin Yang,Jianjun Zhang,Danwen Xu,Jiawen Fan,Huoying Shi,Shifeng Wang,Xiufan Liu 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.3

The subtype H9N2 avian influenza virus greatly threatens the Chinese poultry industry, even with annual vaccination. Waterfowl can be asymptomatically infected with the H9N2 virus. In this study, three H9N2 virus strains, designated A/Goose/Jiangsu/YZ527/2011 (H9N2, Gs/JS/YZ527/11), A/Goose/Jiangsu/SQ119/2012 (H9N2, Gs/JS/SQ119/12), and A/Goose/Jiangsu/JD564/2012 (H9N2, Gs/JS/JD564/12), were isolated from domestic geese. Molecular characterization of the three isolates showed that the Gs/JS/YZ527/11 virus is a double-reassortant virus, combining genes of A/Quail/Hong Kong/G1/97 (H9N2, G1/97)-like and A/Chicken/Shanghai/F/98 (H9N2, F/98)-like; the Gs/JS/SQ119/12 virus is a triple-reassortant virus combining genes of G1/97-like, F/98-like, and A/Duck/Shantou/163/2004 (H9N2, ST/163/04)-like. The sequences of Gs/JS/JD564/12 share high homology with those of the F/98 virus, except for the neuraminidase gene, whereas the internal genes of Gs/JS/YZ527/11 and Gs/JS/SQ119/12 are closely related to those of the H7N9 viruses. An infectivity analysis of the three isolates showed that Gs/JS/SQ119/12 and Gs/JS/YZ527/11 replicated well, with seroconversion, in geese and chickens, the Gs/JS/JD564/12 did not infect well in geese or chickens, and the F/98 virus only infected chickens, with seroconversion. Emergence of these new reassortant H9N2 avian influenza viruses indicates that these viruses can infect both chicken and goose and can produce different types of lesions in each species.

Influence of head structure on hydrodynamic characteristics of transonic motion projectiles

Wang, Rui,Yao, Zhong,Li, Daqin,Xu, Baocheng,Wang, Jiawen,Qi, Xiaobin The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

The hydrodynamic characteristic of transonic motion projectiles with different head diameters are investigated by numerical simulation. Compressibility effect in liquid-phase water are modeled using the Tait state equation. The result shows that with increasing of velocity the compression waves transfer to shock waves, which cause the significant increasing of pressure and decreasing the dimensions of supercavities. While the increasing of head diameter, the thickness, the vapor volume fraction and the drag coefficient of supercavities are all enhanced, which is conducive to the stability of transonic-speed projectiles. The cavity dynamics of the different head projectiles are compared, and the results shows when Mach number is in high region, the truncated cone head projectile is enveloped by a cavity which results in less drag and better stability.

Influence of head structure on hydrodynamic characteristics of transonic motion projectiles

Wang, Rui,Yao, Zhong,Li, Daqin,Xu, Baocheng,Wang, Jiawen,Qi, Xiaobin The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

The hydrodynamic characteristic of transonic motion projectiles with different head diameters are investigated by numerical simulation. Compressibility effect in liquid-phase water are modeled using the Tait state equation. The result shows that with increasing of velocity the compression waves transfer to shock waves, which cause the significant increasing of pressure and decreasing the dimensions of supercavities. While the increasing of head diameter, the thickness, the vapor volume fraction and the drag coefficient of supercavities are all enhanced, which is conducive to the stability of transonic-speed projectiles. The cavity dynamics of the different head projectiles are compared, and the results shows when Mach number is in high region, the truncated cone head projectile is enveloped by a cavity which results in less drag and better stability.

Dominant genera of cyanobacteria in Lake Taihu and their relationships with environmental factors

Lijun Feng,Shiyou Liu,Wenxian Wu,Jiawen Ma,Pei Li,Hailing Xu,Na Li,Yaoyu Feng 한국미생물학회 2016 The journal of microbiology Vol.54 No.7

Cyanobacterial blooms in freshwaters have become one of the most widespread of environmental problems and threaten water resources worldwide. Previous studies on cyanobacteria in Lake Taihu often collected samples from one site (like Meiliang Bay or Zhushan Bay) and focused on the variation in patterns or abundance of Microcystis during the blooming season. However, the distribution of cyanobacteria in Lake Taihu shows differing pattern in various seasons. In this study, water samples were collected monthly for one year at five sites in Lake Taihu with different trophic status and a physicochemical analysis and denaturing gradient gel electrophoresis (DGGE) were conducted. DGGE fingerprint analysis showed that Microcystis (7/35 bands) and Synechococcus (12/35 bands) were the two most dominant genera present during the study period at all five sites. Cyanobium (3/35 bands) was the third most common genus which has seldom been previously reported in Lake Taihu. Redundancy analysis (RDA) indicated that the cyanobacterial community structure was significantly correlated with NO3 --N, CODMn, and NH4 +-N in the winter and spring, whereas it was correlated with water temperature in the summer and autumn. Limiting the nutrient input (especially of N and C loading) in Lake Taihu would be a key factor in controlling the growth of different genera of cyanobacteria.

Self-regulated learning strategies and student video engagement trajectory in a video-based asynchronous online course: a Bayesian latent growth modeling approach

김동호,조일현,송동길,Hua Zheng,Li, Jingwei,Zhu, Jiawen,Huang, Xing,Yan, Wei,Xu, Zhen 서울대학교 교육연구소 2021 Asia Pacific Education Review Vol.22 No.2

The self-paced nature of asynchronous online learning (AOL) is recognized as an obstacle that disrupts student success in the learning environment. Without on-time interventions provided by instructors, students find it challenging to use learning strategies tailored to the learning environment, and their use of self-regulated learning (SRL) strategies has been regarded one of the key indicators of success in AOL. To examine how student SRL strategies are associated with their video engagement trajectory and learning outcomes, we used student video engagement data collected at multiple time points. Participants were 159 students who were taking a self-paced asynchronous online statistics course. Results revealed that student video engagement was found to increase over time and student management strategies contributed to the upward change. We also found that the growth of engagement predicted student achievement in the course. Our findings shed light on instructional strategies to support students in AOL contexts.