RARE METALS
·
2020
·Vol. 40
·期 2
·478-488
·
IF 2.161
Tang Jing,Zheng Sheng-Biao,Jiang Si-Xun,Li Jie,Guo Teng,Guo Jia-Hao
Abstract In this work, the framework of Co nanoparticles and nitrogen-doped carbon nanotubes (Co/NCNTs) derived from metal–organic frameworks (MOFs) through solid pyrolysis was successfully synthesized in the atmosphere of H 2 and Ar gases. The Co/NCNTs composites exhibited superior electrocatalytic performance for tert-butyl hydroquinone (TBHQ) oxidation due to the synergistic effect between chemical composition and the specific structure of Co nanoparticles and nitrogen-doped carbon nanotubes. It was found that the reaction underwent a quasi-reversible redox reaction with 37-fold higher anodic current for TBHQ at Co/NCNT-modified electrode when compared to bare glassy carbon electrode (GCE). In optimal condition, Co/NCNTs/GCE exhibited a linear range of 0.05–80.00 μmol·L −1 for detecting TBHQ, and the limit of detection (LOD) was estimated to be as low as 10 nmol·L −1 (signal/noise of S/N = 3). Moreover, the as-obtained modified electrode was successfully used to assay the content of TBHQ in edible oil samples. Graphic abstract
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高影响因子
BMC Complementary Medicine and Therapies
·
2020
·Vol. 20
·期 1
·1-10
·
IF 0
Liu Shou Gang,Luo Guang Pu,Qu Yong Bin,Chen Yong Feng
Background Psoriasis is a common inflammatory skin disease. Abnormal proliferation of keratinocytes is one of the psoriatic histopathological features. Indirubin has an essential effect on the proliferation and activation of keratinocytes; however, in psoriasis, the specific mechanism of action of indirubin on keratinocytes is unclear. In the present study, we revealed the effects of indirubin on DNA methyltransferase 1 (DNMT1), wnt inhibitory factor 1 (wif-1), and wnt/β-catenin signal pathway, in the meantime, we explored the effects of indirubin on proliferation, cell cycle and the apoptosis of HaCaT cells.Methods The expression of DNMT1, wif-1, Frizzled2, Frizzled5, and β-catenin in HaCaT cells treated with different concentrations of indirubin were detected by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). The expression levels of DNMT1 and wif-1 were observed after treated with different concentrations of indirubin by enzyme-linked immunosorbent assay (ELISA). The wif-1 promoter methylation status was detected by DNA methylation-specific PCR (MSP). The transcriptional activities of wif-1 and β-catenin were discovered by a luciferase reporter gene system. Cell viability was determined by Cell Counting Kit-8 (CCK8) method. The cell cycle was detected by flow cytometry. The apoptotic cells were surveyed by the apoptosis kit. The expression of Inolucrin, Loricrin, Filaggrin, Keratin 17, and transcriptional activation of transglutaminase 1(TGase1) were detected by Western blotting.Results Indirubin inhibited the expression of DNMT1 and the methylation of the wif-1 promoter. In the wnt signal pathway, indirubin restored the protein expression of wif-1 and inhibited expression of Frizzled2, Frizzled5, and β-catenin. Besides, indirubin inhibited the proliferation of HaCaT cells, induced apoptosis, and arrest cell cycle. We also reported that indirubin could down-regulate the expression of Involucrin, TGase 1, and keratin 17, but the expression of Filaggrin and Loricrin had no significant effect.Conclusion Our research showed that indirubin promoted the demethylation of wif-1 and suppressed the wnt/β-catenin signal pathway, thereby exerted an anti-proliferative effect. This study reveals the anti-proliferation mechanism of indirubin, which may provide an effective option for the treatment of proliferative diseases.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2020
·Vol. 193
·期 1
·205-217
·
IF 2.277
Wan Lijun,Gao Zhen,Wu Bin,Cao Fei,Jiang Min,Wei Ping,Jia Honghua
Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)–solid (corncob) ratio was 0.33, solid (corncob)–liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis , and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.
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高影响因子
Science China-Chemistry
·
2020
·Vol. 63
·期 10
·1507-1514
·
IF 6.356
Yin Kun,Zeng Xi,Liang Xuan,Wei Haopai,Zeng Huimin,Qi Wei,Ruan Weidong,Song Yanling,Yang Chaoyong,Zhu Zhi
Droplet microfluidics is a powerful platform for high-throughput single-molecule protein analysis. However, the issues of coalescence and crosstalk of droplets compromise the accuracy of detection and hinder its wide application. To address these limitations, a novel colloidosome-based method was presented by combining a Pickering emulsion with droplet microfluidics for single-molecule protein analysis. Utilizing the self-assembly of easily synthesized colloidal surfactant F-SiO 2 NPs at the water/oil interface, the colloidosomes are rigidly stabilized and can effectively avoid the leakage of fluorescent molecules. The crosstalk-free colloidosomes enable high-throughput single-molecule protein analysis, including heterogenous dynamic studies and digital detection. As a robust and accurate method, colloidosome-based microfluidics is promising as a powerful tool for a wide variety of applications, such as directed enzyme evolution, digital enzyme-linked immunosorbent assay (ELISA), and screening of antibiotics.
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JOURNAL OF NANOBIOTECHNOLOGY
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2020
·Vol. 18
·期 1
·1-13
·
IF 6.518
Wu Yiyong,Deng Peihong,Tian Yaling,Feng Jinxia,Xiao Jingyun,Li Junhua,Liu Jun,Li Guangli,He Quanguo
A method with high sensitivity, good accuracy and fast response is of ever increasing importance for the simultaneous detection of AA, DA and UA. In this paper, a simple and sensitive electrochemical sensor, which based on the polyvinylpyrrolidone (PVP)-graphene composite film modified glassy carbon electrode (PVP-GR/GCE), was presented for detecting ascorbic acid (AA), dopamine (DA) and uric acid (UA) simultaneously. The PVP-GR/GCE has excellent electrocatalytic activity for the oxidation of AA, DA and UA. The second-order derivative linear sweep voltammetry was used for the electrochemical measurements. The peak potential differences of DA-AA, DA-UA, and UA-AA (measured on the PVP-GR/GCE) were 212, 130 and 342 mV respectively. Besides, the over potential of AA, DA and UA reduced obviously, so did the peak current increase. Under the optimum conditions, the linear ranges of AA, DA and UA were 4.0 μM–1.0 mM, 0.02–100 μM, and 0.04–100 μM, respectively. The detection limits were 0.8 μM, 0.002 μM and 0.02 μM for AA, DA, and UA. The electrochemical sensor presented the advantages of high sensitivity and selectivity, excellent reproducibility and long-term stability. Furthermore, the sensor was successfully applied to the analysis of real samples.
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高影响因子
POLYMER BULLETIN
·
2020
·Vol. 78
·期 8
·4403-4417
·
IF 2.014
Zhu Yongfei,Li Peilin,Lin Runsheng,Su Junming
Both pyrogallol-furfurylamine-based and pyrogallol-aniline-based di-benzoxazines (PG-FA and PG-A) possess a free hydroxyl and latent catalytic characteristics. To decrease the ring-opening polymerization (ROP) temperature of benzoxazine based on phenol and 4,4′-diaminodiphenylmethane (P-DDM) and increase simultaneously thermal property of its polymer, PG-FA and PG-A as catalysts were introduced into P-DDM. DSC and FTIR tests were used to investigate the effect of PG-FA and PG-A on the ROP of P-DDM; DMA, FTIR and TGA were performed to study their effects on the hydrogen bonds and thermal property of the cured P-DDM (PP-DDM). The results indicate that the ROP temperature of P-DDM remarkably decreased with the incorporation of PG-FA and PG-A. FTIR and DMA results illustrate that the total amounts of hydrogen bonds in PP-DDM increased with the addition of PG-FA or PG-A; however, its fraction of –OH⋯N (intra) and O − ⋯ + HN (intra) hydrogen bonds decreased. The decrease in –OH⋯N hydrogen bonds made the cross-linked density of polybenzoxazine increase, resulting in that the thermal stability of PP-DDM enhanced with the introduction of PG-FA and PG-A.
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 39
·期 7
·874-886
·
IF 3.603
Zhang Hang-Tian,Wei Zhi-Tao,Zhang Fang,Yang Tian,Wu Yi-Xian
Poly(styrene- b -isobutylene- b -styrene) triblock copolymer (SIBS), a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments, could be synthesized via living cationic copolymerization. A novel poly[(styrene- co -methylstyrene)- b -isobutylene- b -(styrene- co -methylstyrene)]- g -polytetrahydrofuran (M-SIBS- g -PTHF) block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS. A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol −1 to 4200 g·mol −1 were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran (THF) coinitiated by AgClO 4 . The introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene (PIB), polystyrene (PS) and PTHF. Moreover, the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months, leading to insolubility of the copolymers even in good solvents. The melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS- g 5 -PTHF-1.1k block graft copolymer increased remarkably up to 153 °C and 117.0 J·g −1 by 23 °C and 11.6 J·g −1 respectively after storage for long time. Storage modulus (G′) is higher than loss modulus (G″) of M-SIBS- g -PTHF block graft copolymer at temperatures ranging from 100 °C to 180 °C, which is much higher than those of the SIBS triblock copolymer. To the best of our knowledge, this is the first example of high performance M-SIBS- g -PTHF block graft copolymers containing segments of PIB, PS and PTHF with nanocrystallization-locked architecture.
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高影响因子
Optoelectronics Letters
·
2020
·Vol. 16
·期 6
·401-404
·
IF 0
Li Shi-na,Ma Rui-xin,Niu Jian-wen
Cu 2 NiSnS 4 nanoparticles were prepared for the first time using a facile solid-phase process at a temperature of 180°C. The crystalline structure, morphology and optical properties of the Cu 2 NiSnS 4 nanoparticles were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM) and ultraviolet-visible (UV-vis) spectrophotometer. The band gap and conversion efficiency of Cu 2 NiSnS 4 nanoparticles were studied at various temperature. The results showed that the Cu 2 NiSnS 4 nanoparticles exhibited an optimum band gap of 1.58 eV and a conversion efficiency of 0.64% at 180 °C, indicating that it maybe be useful in low-cost thin film solar cells.
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CATALYSIS LETTERS
·
2020
·Vol. 151
·期 5
·1330-1335
·
IF 2.482
Wang Weitao,Wei Yaoyao,Jiang Xulu,He Zhen-Hong,Zhang Cunshe,Liu Zhao-Tie
Abstract Direct hydroxylation of benzene to phenol with dioxygen is a green route for synthesis of phenol. The higher bonding energies of C–H in benzene and O–O in dioxygen make metal-free catalysis a challenge. A novel metal-free catalyst of quinone-cylcohexanone-formaldehyde polymer was rationally designed and prepared. The polymer was characterized with FT-IR, XRD, Raman, SEM, 13 C NMR and XPS. Abundant oxygen functional groups of cyclic ketonic, quinone carbonyl and hydroquinone were found on the surface of polymer. The catalytic performances for hydroxylation of benzene to phenol with dioxygen over the metal-free catalyst were investigated and a phenol yielding of 11.4% was achieved. Moreover, the reaction mechanism was proposed. Graphic Abstract
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CATALYSIS LETTERS
·
2020
·Vol. 151
·期 5
·1282-1292
·
IF 2.482
Chen Mei-Jun,Yang Gang,Zhang Shi-Rong,Wu Jun,Zhang Yan-Zong,He Jing-Song,Song Chun,Huang Chu-Rui,Long Lu-Lu
Abstract Tetracycline (TC), as a typical micro-pollutant in natural environment, has attracted much attention. The peroxymonosulfate (PMS)-based advanced oxidation process is regarded as a promising technology for TC treatment, while its potential practical application is mainly dependent on the oxidant yield derived from activating PMS by catalysts. Therefore, the development of improved activators which are characterized by adequate activity and stability for PMS decomposition is in high demand. In this paper, the high-efficiency K 2−x Mn 8 O 16 nanowire hydrogels (KNH) with high stability was synthesized through a simple hydrothermal method and then an enhanced PMS/KNH system for antibiotic degradation via multiple strategies was established. For removal of low-concentration TC, a high degradation of nearly 95% could be achieved by activating PMS in a wide pH rang. More than that, a further catalytic mechanism of this PMS/KNH system was also put forward, thus providing a guideline for designing and fabricating transition-metal catalysts to activate PMS. Graphic Abstract
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Journal of the Australian Ceramic Society
·
2020
·Vol. 57
·期 1
·97-105
·
IF 1.307
Zhou Kui,Zou Jiawei,Chi Wenchao,Lin Yanjun,Li Wenchao,Cao Chuanliang
A new and precise control printing method was developed for preparing homogeneous microspheres. Hydroxyapatite-sodium alginate (HA-SA) mixed suspension was used as printing material and CaCl 2 solution was used as solidifying liquid to prepared ceramic microspheres by pneumatic extrusion printing technology. By adjusting the positive pressure, dwell time, and hydroxyapatite concentration, the influence of each parameter on the shape of printed microspheres was studied, and the suitable preparation parameters were determined. Then, the microspheres with uniform particle size distribution were successfully prepared in large quantities by selecting appropriate printing parameters. Then, the microspheres were dried and sintered at different temperatures. During the drying and sintering process, the microspheres showed obvious shrinkage, but still keep good sphericity. The phases of sintered microspheres are hydroxyapatite and calcium oxide. The microstructure shows typical hydroxyapatite grain characteristics.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 10
·1-9
·
IF 6.232
Liu Hui,Liu Bowen,Huang Pengcheng,Wu Yangyang,Wu Fang-Ying,Ma Lihua
Gold nanoparticles (AuNPs) catalyze the mild reaction between the weak reducing agent kojic acid (KA) and silver ions (Ag + ) to form Au@Ag bimetallic NPs by the combination of the intrinsic catalysis with plasmonic properties This is proposed as a novel optical assay to determine the tyrosinase (TYRase) concentration. The nanoparticles have been characterized by UV-vis spectroscopy, transmission electron microscope (TEM) images, and X-ray photoelectron spectroscopy (XPS). The sensing mechanism is based on the fact that KA binds to TYRase by chelating with dicopper active site of TYRase and the introduction of TYRase restrains the Au@Ag bimetallic NP formation by the precedent binding with KA. A clear color variation from yellow to pink and UV-vis spectral changes are observed at the optimal wavelength of 410 nm. The assay works in the range 0.13~0.73 U mL −1 with a detection limit (LOD) of 0.019 U mL −1 . The impact from matrix interfering substances including glucose, uric acid, common oxidases, and amino acids is negligible. The applicability is demonstrated by quantitative determination of TYRase in human serum samples with 74 to 89% recovery and RSD less than 4.0%, which accords with the level for bio-sample analysis.
Schematic presentation of colorimetric assay for tyrosinase (TYRase) based on the inhibition effect on silver deposition onto catalytically active gold nanoparticles (AuNPs) and its application with a smartphone. Tyrosinase (TYRase); silver ions (Ag + ); kojic acid (KA); gold nanoparticles (AuNPs); gold-silver core-shell nanoparticles (Au@Ag NPs)
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高影响因子
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