Sensitive detection of levofloxacin and copper (II) based on fluorescence ‘‘turn on-off” of biomass carbonized polymer dots

Jiasheng Lin,Shuliang Yang,Yanjie Wang,Yahan Cui,Qiaoyan Li,Yanhua Chen,Lan Ding 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

A novel type of biomass carbonized polymer dots (CS-CPDs) with green fluorescence emission were synthesizedvia a one-step microwave-assisted method, using chitosan and maleic acid as the precursors. The fluorescence intensity of CS-CPDs was selectively enhanced (turn on) with increasing levofloxacin(LEV) concentration based on Aggregation Induced Emission Enhancement. The linear range of thismethod was 1–35 lmol/L, with the limit of detection of 0.20 lmol/L. Furthermore, we demonstrated thatthe fluorescence intensity of CS-CPDs/LEV was restored (turn on-off) due to the addition of copper (II),which could assemble a more stable Cu2+/LEV complex through coordination. For the first time, CSCPDswere utilized as a selective fluorescent ‘‘turn on-off” probe for the continuous detection of LEVand Cu2+. Excellent results were also obtained in environmental water samples analysis with recoveriesranging of 91.3–99.6% and 97.7–113.4%, respectively. Moreover, the prepared CS-CPDs exhibited excellentoptical stability and large Stokes shift (139 nm), which predicted broad application prospects inthe field of fluorescence sensing.

EFFECT OF MACROMOLECULAR COUPLING AGENT PMMA-b-PVTES ON STABILIZING NANO-Si3N4

HUI ZHU,Jiasheng Qian,Peng Chen,JIBIN MIAO,RU XIA,Bin Yang,LIFEN SU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8

Poly(methyl methacrylate)-b-poly(vinyltriethoxysilane) (PMMA-b-PVTES) are synthesized using atom transfer radical polymerization (ATRP) and used as macromolecular coupling agents to modify silicon nitride nanoparticles (nano-Si3N4). The chemical composition of copolymers PMMA-b-PVTES and modified nano-Si3N4 are confirmed by various characterization techniques. The modified nano-Si3N4 shows excellent hydrophobic nature, which make nanoparticles (NPs) stably disperse in organic solvent. Transmission electron microscope (TEM), particle size testing, contact angle measuring and sedimentation experiment are employed to examine the dispersion of modified nano-Si3N4 in chloroform. By comparing the effects of copolymers with varied number-average molecular weight (Mn) and block length ratio on stabilizing nano-Si3N4, we discussed the mechanism of macromolecular coupling agent stabilizing NPs. In our experiments, the copolymer PMMA88-b-PVTES17 is found to be the most effective macromolecular coupling agent for stabilizing nano-Si3N4.

Preparation and Study on Thermal Conductive Composites of Chlorinated Polyethylene Rubber Reinforced by Boron Nitride Particles

Junjie Shu,Ru Xia,Jiasheng Qian,JIBIN MIAO,LIFEN SU,Ming Cao,Hongyun Lin,Peng Chen,Jinyang Chen 한국고분자학회 2016 Macromolecular Research Vol.24 No.7

The composites of chlorinated polyethylene rubber (CM) filled with boron nitride (BN) were prepared and examined systematically. Scanning electron microscopy (SEM) was used to observe microscopic morphology of composites. Mechanical properties of composites were analyzed by a rubber process analyzer (RPA) and dynamic mechanical thermal analyzer (DMTA). Thermal conductivity as well as thermo stability of composites was improved by adding BN particles into the CM rubber. It was found that BN particles can reinforce the rubber matrix while they also break down the network of polymer chains and ruin the physical properties of the rubber matrix. During the dynamic compressing process, BN particles can transfer heat from the matrix and alleviate the heat build-up phenomenon. The BN/CM composites (volume content CBN=18%) with thermal conductivity 1.179 W/(m·K) and good flexibility (Elongation at break=320%) were prepared, which may be used as thermal interface materials in a dynamic compressing process.

Monte Carlo Simulation on Kinetics of Batch and Semi-Batch Free Radical Polymerization

Jing Shao,Peng Chen,Wei Tang,Ru Xia,Xiaoshuang Feng,Jiasheng Qian,Changjiang Song 한국고분자학회 2015 Macromolecular Research Vol.23 No.11

Based on Monte Carlo simulation technology, we proposed a hybrid routine which combines reaction mechanism together with coarse-grained molecular simulation to study the kinetics of free radical polymerization. By comparing with previous experimental and simulation studies, we showed the capability of our Monte Carlo scheme on representing polymerization kinetics in batch and semi-batch processes. Various kinetics information, such as instant monomer conversion, molecular weight, and polydispersity etc. are readily calculated from Monte Carlo simulation. The kinetic constants such as polymerization rate kp is determined in the simulation without of “steady-state” hypothesis. We explored the mechanism for the variation of polymerization kinetics those observed in previous studies, as well as polymerization-induced phase separation. Our Monte Carlo simulation scheme is versatile on studying polymerization kinetics in batch and semi-batch processes.

A Phase-shifting Control IPOS High-voltage Generator with Low Output Voltage Ripple for X-Ray

Hongyu Feng,Hongyi Lin,Jiasheng Xu,Liang Wu,Guozhu Chen 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

A high-voltage (HV) generator with phase-shifting closed-loop control for X-ray is proposed. The LCC topology with input parallel output series (IPOS) is used in the circuit, and the phase-shifting closed-loop control is adopted to reduce the output voltage ripple further. In this paper, the LCC resonant converter is modeled based on fundamental harmonic approximation (FHA), and the output voltage ripple of a single module transformer is derived. On this basis, the output ripple of the multi-module LCC cascade converter is calculated and analyzed. Aiming at the problem that the ripple cancellation effect deteriorates due to the inconsistent parameters between modules, a phase locked loop (PLL) phase-shifting closed-loop control strategy is proposed. The simulation and experiment results show that the control method is feasible and reasonable.

The complete mitochondrial genome of Hemigrapsus sinensis (Brachyura, Grapsoidea, Varunidae) and its phylogenetic position within Grapsoidea

Jin Xun,Guo Xingle,Chen Jian,Li Jiasheng,Zhang Shufei,Zheng Sixu,Wang Yunpeng,Peng Ying,Zhang Kun,Liu Yifan,Liu Bingjian 한국유전학회 2023 Genes & Genomics Vol.45 No.3

Background In this study, the complete mitogenome of Hemigrapsus sinensis was the first identified and analyzed. Objective The complete mitochondrial genome of Hemigrapsus sinensis (Brachyura, Grapsoidea, Varunidae) and its phylogenetic position within Grapsoidea. Methods The sample of Hemigrapsus sinensis was collected and DNA was extracted. After sequencing, NOVOPlasty was used for sequence assembly. Annotate sequences with MITOS WebServer, tRNAscan-SE2.0, and NCBI database. MEGA was used for sequence analysis and Phylosuite was used for phylogenetic tree construction. DnaSP was used to calculate Ka/Ks. Results This mitochondrial genome shows that it was 15,900 bp and encoded 13 PCGs, 22 tRNA genes, two rRNA genes, and one control region. The genome composition tends to A + T (74.34%) and presents a negative GC-skew (− 0.22) and AT-skew (− 0.03). The PCGs initiation codon was the typical ATN and termination codon was the typical TAN, incomplete T or missing. The ML and BI trees showed that H. sinensis was most closely related to Hemigrapsus and clustered together with the Varunidae. And our phylogenetic trees provide proof that Ocypodoidea and Grapsoidea may be of common origin. Meanwhile, in the phylogenetic tree, parallel mixing of Chiromantes and Orisarma raised doubts over the traditional classification system. Besides, Incomplete Lineage sorting (ILS) was observed in Varunidae. In the subsequent analysis of evolution rate, we found that all of the PCGs (NAD4 was not calculated) had undergone negative selections, indicating the conservation of mitochondrial genes of H. sinensis during the evolution. Conclusion Therefore, researching the complete mitogenome of H. sinensis would be contributing to molecular taxonomy, phylogenetic relationship, and breeding optimization within the Grapsoidea superfamily.

Targeted capture enrichment and sequencing identifies HLA variants associated with the severity of COVID-19

Liu Chuanmiao,Zhang Li,Chen Jiasheng,Gao Yu 한국유전학회 2023 Genes & Genomics Vol.45 No.4

Background Coronavirus disease 2019 (COVID-19) is currently a global pandemic. The pathogenesis of severe COVID-19 has been widely investigated, but it is still unclear. Human leukocyte antigen (HLA) plays a central role in immune response, and its variants might be related to COVID-19 progression and severity. Objective To investigate the hypothesis that individual HLA variations could alter the course of COVID-19 and might be associated with the severity of COVID-19. Methods In this study, we conducted an HLA targeted capture enrichment and sequencing of severe COVID-19 patients matched to mild cases. A total of 16 COVID-19 patients, confirmed by SARS-CoV-2 viral RNA polymerase-chain-reaction (PCR) test and chest computed tomography (CT) scan, were enrolled in this study. The HLA targeted capture enrichment and sequencing were conducted. HLA typing was performed by comparing contigs with IPD-IMGT/HLA Database. Results In this study, 139 four-digit resolution HLA alleles were acquired. The results showed that HLA-DRB3*01:01 allele was significantly associated with the severity of COVID-19 (odds ratio [OR] = 27.64, 95% confidence interval [CI] = 1.35–560.50, P = 0.0064). And HLA-K*01:01 might be a potential risk factor for COVID-19 severity (OR = 0.11, 95% CI = 0.017–0.66, P = 0.019), but HLA-K*01:02 might be a protective factor (OR = 7.50, 95% CI = 1.48–37.92, P = 0.019). Conclusion Three non-classical HLA alleles, including HLA-DRB3*01:01, HLA-K*01:01, HLA-K*01:02 were identified to be associated with the severity of COVID-19 by comparing mild and severe patients. The current findings would be helpful for exploring the influence of HLA gene polymorphisms on the development and severity of COVID-19.

Morphology, Thermal and Crystallization Properties of Polyamide-6/Boron Nitride (BN) Thermal Conductive Composites

Ru Xia,Manman Sun,Bin Yang,Jiasheng Qian,Peng Chen,Ming Cao,JIBIN MIAO,LIFEN SU 한국고분자학회 2018 폴리머 Vol.42 No.2

A series of the thermal conductive polyamide-6 (PA6) composites filled with boron nitride (BN) were prepared by two methods, including melting method (MM) and solution method (SM). The thermal conductivity, morphology, crystallization behavior, thermal stability, and rheological properties of PA6 composites were investigated. The results showed that the thermal conductivity of two methods increased with increase in the filler content, the thermal conductivity of PA6/BN composites containing 40 wt% BN prepared by melting method was up to 1.02W·m-1·K-1, while the thermal conductivity of PA6/BN composites prepared by solution method was up to 1.44 W·m-1·K-1 at the same filler content.

Effect of Microstructure on Thermal Conductivity of Polymer Composites

Yue Yang,Junjie Shu,Peng Chen,Ru Xia,Jiasheng Qian,Bin Yang,JIBIN MIAO,LIFEN SU,Zhengzhi Zheng,Ming Cao 한국고분자학회 2017 Macromolecular Research Vol.25 No.4

Thermal conductivity (TC) of polymer composites is strongly depended on thermal conductive fillers as well as heat conduction pathways formed by these fillers. In this work, we examined effects of morphology, size and arrangement of fillers on TC of polymer composites by using energy-conserving dissipative particle dynamic (e-DPD) simulation. Theoretically, we explored effects of ideal and “pseudo” thermal conductive pathways on composites’ TC and investigated heat conduction of filler particles with cubic-center and lamellar morphology. To confirm orientation and size effects of lamellar filler particles on composites’ TC, we prepared a series of Boron Nitride/Silicon rubber composites (BN/SiR). Being same with those observed in e-DPD simulation, orientation could efficiently improve TC of BN/SiR composites. The TC of composites with filled diameters about 10 micrometer of BN flats is 11 times higher than that of SiR matrix. Our researching results show that heat conduction pathways are essential to transportation of heat flux in polymer composites and even “pseudo” pathways by disconnected filler particles along temperature gradient can accelerate heat conduction.

In situ monitoring of pore structure of magnesium oxysulfate cement paste: Effect of MgSO4/H2O ratio

Shengwen Tang,Changrong Wei,Rongjin Cai,Jiasheng Huang,E. Chen,Junhui Yuan 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

This work systematically presented the pore structure evolution of different magnesium oxysulfate(MOS) cement pastes by non-contact impedance measurement (NCIM), fractal theory and othermicrostructural experiments. According to the evolution of electrical impedance response, threehydration stages (dissolution, acceleration and hardened stages) can be identified in the pastes. Furthermore, based on the results obtained from NCIM and fractal theory, the porosity, incremental porevolume, pore tortuosity, average pore diameter and maximal pore diameter of MOS cement pastes areinvestigated. The influence of MgSO4/H2O ratio on pore structure of MOS cement paste is primarilyexplained. It can be inferred from predicted and experimental results that NCIM is a good method toanalyze the microstructure evolution of MOS cement pastes in-situ.