BIOMACROMOLECULES
·
2021
·
IF 6.988
Yu Zhang,Bo Xia,Yanyan Li,Xianfu Lin,Qi Wu
The synthesis of optically pure polymers is one of the most challenging tasks in polymer chemistry. Herein, Novozym 435 (Lipase B from Candida antarctica, immobilized on Lewatit VP OC 1600)-catalyzed polycondensation between d-/l-aspartic acid (Asp) diester and diols for the preparation of helical chiral polyesters was reported. Compared with d-Asp diesters, the fast-reacting l-Asp diesters easily reacted with diols to provide a series of chiral polyesters containing N-substitutional l-Asp repeating units. Besides amino acid configuration, N-substituent side chains and the chain length of diols were also investigated and optimized. It was found that bulky acyl N-substitutional groups like N-Boc and N-Cbz were more favorable for this polymerization than small ones probably due to competitively binding of these small acyl groups into the active site of Novozym 435. The highest molecular weight can reach up to 39.5 × 103 g/mol (Mw,Đ = 1.64). Moreover, the slow-reacting d-Asp diesters were also successfully polymerized by modifying the substrate structure to create a “nonchiral” condensation environment artificially. These enantiocomplementary chiral polyesters are thermally stable and have specific helical structures, which was confirmed by circular dichroism (CD) spectra, scanning electron microscope (SEM), and molecular calculation.
研究领域:
高分子化学
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生物催化
·
材料科学
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DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2016
·Vol. 28
·期 3
·367-372
·
IF 1.823
Zhenling Shen,Xin Zhi,Puyu Zhang
Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP-Try-SEA) was synthesized from the polysuccinimide with 2 -aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR, 1 H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore-indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO 3 with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO 4 , achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO 3 and CaSO 4 deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
CELL BIOCHEMISTRY AND BIOPHYSICS
·
2014
·Vol. 71
·期 1
·367-373
·
IF 2.38
Gan Maozhou,Yin Xiaodong
This research designed to explore the antitumor activity of puerarin against human mantle cell lymphoma (MCL). Cell proliferation and apoptosis were assessed by MTS and flow cytometry. Caspase-3, -8, and -9 activities were assessed with the colorimetric caspase protease assay. Apoptotic proteins like PARP, cyclin D1, Bcl-2 family, XIAP, and cIAP I were researched by western blot. The PI3K inhibitor LY294002 was used to investigate the possible mechanism relating the PI3K/Akt signaling pathway. Puerarin in vitro inhibited proliferation and induced apoptosis of Z138 cells. Expressions of PI3K and p-Akt were downregulated by puerarin. Puerarin negatively regulated NF-κB activity by inhibiting NF-κB phosphorylation with nuclear translocation inhibition. This kind of effects was correlated with the suppression of expression of cyclin D1, BAX, Bcl-2, XIAP etc. This function was modulated by the PI3K inhibitor. Our results demonstrated that puerarin can induce growth arrest and apoptosis in MCL cells and that the mechanism may involve the NF-κB signaling pathway. Puerarin may have therapeutic applications in the treatment of MCL.
研究领域:
肿瘤学
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药理学
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细胞生物学
·
信号转导
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产品关联
DOI
PubMed
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 9
·2157-2172
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IF 2.41
Chen Xing Juan,Cai Jian Chong,Zhang Zheng Han,Liu Li Jia,Yang Guang Lei
A novel cross-linked chitosan-poly(aspartic acid) chelating resin was synthesized by combining chitosan and poly(aspartic acid) derivative with crosslinker. The structure and morphology of the resin containing disulfide bonds were characterized by 1 H NMR, FT-IR, Raman spectra, and SEM. Adsorption of Pb(II) and Hg(II) from aqueous solution by the resulted chelating resin was investigated in batch techniques. The result of the Raman spectra suggests that the disulfide bonds in the resin also play an important role in the adsorption of Pb(II) and Hg(II). The kinetic data were fitted to pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, which is suggestive of following closely the pseudo-second-order kinetic model. Equilibrium data were fitted to Langmuir, Freundlich, and D–R isotherm models. The results of equilibrium isotherm reveal that the empirical Langmuir equation provides an accurate description of the experimental data under the studied concentration range. In addition, thermodynamic and regeneration properties of the adsorbent were also studied.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Energies
·
2024
·Vol. 17
·期 13
·3195
·
IF 3
WenLong Gao,LiWei Sun,Miao Li,XiAn Ye,QingChun Gao,DongLiang Kong,JunPu An,KuoBo Wang,Fan Yang
This paper focuses on the selection and application of scale inhibitor by studying the problem of pipeline scaling in geothermal well development. Adding scale inhibitor can effectively reduce the treatment cost and achieve a good scale resistance effect, but the commonly used polyaspartic acid scale inhibitor has problems such as poor scale inhibition effect and large use limitations. Therefore, a new modified polyaspartic acid scale inhibitor (His-Tyr-SA-PASP) was prepared using polysuccinimide (PSI) as the raw material and histidine (His), tyrosine (Tyr), and sulfonic acid (SA) as the modification reagent. When the dosage of His-Tyr-SA-PASP was 8 mg/L, the scale inhibition rate of CaCO3was 94.40%. In addition, the scale inhibition effect of His-Tyr-SA-PASP on CaCO3was better than that of PASP. At the same time, under the condition of a static experiment at 75 °C, according to the ion concentration of water samples in different scale zones, this paper also identified the ratio of four composite scale inhibitors. When the dosage of compound scale inhibitor was 100 mg/L, Sodium of Polyaspartic Acid–Diethylene Triamine Penta (Methylene Phosphonic Acid)–2-Phosphonobutane-1,2,4-Tricarboxylic Acid–Amino Trimethylene Phosphonic Acid–Copolymer of Maleic and Acrylic Acid = (10:10:5:1:9), (15:10:5:2.5:2.5), (12.5:5:10:1:6.5), and (15:5:10:4:1) and the scale inhibition rate was more than 95%. Under the condition of a dynamic experiment, the optimized composite scale inhibitor still showed a scale inhibition rate of more than 90%. It provides a useful reference for the practical application of water treatment in geothermal wells and has the prospect of industrial application.
研究领域:
化学工程
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材料科学
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环境科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2020
·Vol. 56
·期 1
·441-451
·
IF 2.773
Geng Yang,Rui Wang,Jing-Rong Gao,Debao Niu,Jian Li,Qing-Hui Wen,Xin-An Zeng
Summary The effect of moderate pulsed electric fields (MPEF) strength on autolysis of Saccharomyces cerevisiae was evaluated in this study. After exposure to MPEF with intensity of 7 kV cm −1 for 4 ms, the integrity of the cell wall was obviously destroyed and the inactivation of S. cerevisiae reached 99.43%. During the subsequent 42-h autolysis process, the release of free α-amino nitrogen of MPEF-treated cells, as well as extracellular protease activity, was significantly ( P < 0.05) higher than that of untreated cells. Moreover, exposure to 7 kV cm −1 led to an increase of the total amino acid of 149.36%. In particular, the content of aspartic acid and glutamic acid which are important umami flavour precursors increased by 232.55% and 209.40%, respectively. These results indicate that MPEF will be an effective method to accelerate autolysis of S. cerevisiae for obtaining high-quality yeast extract as flavour enhancers and nutrition supplements.
研究领域:
食品科学
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微生物学
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DOI
高影响因子
Advanced Science
·
2025
·
IF 14.1
Ling Zhu,Wei Liu,Yizhou Zhang,Zhifang Wu,Yiru Wang,Yuedan Xu,Haiyan Zheng,Hongli Zhang,Mengfei Yu,Xiaoting Jin,Zhe Wang,Zihuai Zhou,Baiping Fu
Dental caries is a global oral dilemma leading to demineralization of tooth hard tissues and exposure of dentinal tubules (DTs). Multifunctional restorative strategies, including remineralization, antibacterial properties, and DT occlusion, are urgently needed for dental caries management but remain a significant challenge. Herein, the polyaspartic acid-calcium-lanthanum suspension (5 g L −1 -3.06 м-0.34 м) followed by phosphate solution (2.04 м) is adopted to conduct polyelectrolyte-cation complexes pre-precursor process. This strategy, for the first time, successfully induces La-doped intrafibrillar mineralization of collagen fibrils with lanthanum-doped hydroxyapatite (La-HAp). After sequential application of two mineralization media, the demineralized dentin is fully remineralized and the DTs are deeply occluded to a depth of 100 µm with La-HAp after 7 d of incubation in artificial saliva or oral cavity of rabbit. The remineralized dentin demonstrates antibacterial properties against cariogenic bacteria ( Streptococcus mutans ) both in vitro and in vivo, and its mechanical properties are almost restored to those of intact dentin. The mineralization media cause no apparent irritation to oral mucosa or dental pulp. Hence, this multifunctional strategy confers the remineralized dentin surface with antibacterial properties and blocks the invasion of cariogenic bacteria through DTs, providing insight into the clinical management of dentin caries accompanied by dentin hypersensitivity.
研究领域:
口腔医学
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材料科学
·
生物医学工程
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产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2025
·
IF 5
Jingyang Shi,Jing Lv,Jieliang Wang,Zhao Cao,Wenda Lu,Yongdan Cao,Xu Wu,Xiaoping Wang,Jiayan Tang,Zhenyue Zhang,Ru-an Chi
The flotation separation of parisite from calcium-bearing gangue minerals, such as fluorite and calcite, poses a significant challenge in the rare earth ore production process. In this study, an eco-friendly and highly selective depressant polyaspartic acid (PASP) was adopted in the flotation separation of parisite from calcite and fluorite, and its depression mechanism was investigated through various surface analysis and testing methods, including zeta potential tests, contact angle measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The flotation test results indicated that PASP significantly inhibited the flotation of fluorite and calcite, with negligible effect on parisite when using octyl hydroxamic acid (OHA) as a collector at weak alkaline pH. The artificial mixed mineral flotation proved that PASP could achieve effective flotation separation of parisite from calcite and fluorite. Zeta potential tests and FTIR analyses demonstrated that the adsorption of PASP prevented OHA adsorption on calcite and fluorite surfaces, with minimal impact on OHA adsorption on parisite surface. XPS analyses confirmed that PASP was mainly chemisorbed on the surfaces of calcite and fluorite through the chelation reaction between polar groups (–NH– and –COO − ) of PASP with the Ca 2+ on these surfaces. AFM clearly showed the agglomerative adsorption of PASP on the surfaces of fluorite and calcite. Thus, PASP could be an efficient depressant for calcite and fluorite in parisite flotation, providing novel insights into addressing rare earth ore flotation challenges.
研究领域:
矿物加工工程
·
表面化学
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产品关联
DOI
高影响因子
JOURNAL OF BIOMATERIALS APPLICATIONS
·
2021
·
IF 2.646
Qiang Li,Dongsheng Fu,Jie Zhang,Tianyang Li,Huifang Wang,Wenjuan Hou,Baolong Niu,Ruijie Guo,Yiming Liu
Encapsulation of therapeutic molecules into nanocarrier is an extensively explored strategy to treat cancer more effectively. In this study, pH-responsive targeting dual-agent delivery nanoparticles were prepared, into which hydrophilic doxorubicin hydrochloride (DOX) and hydrophobic curcumin (CUR) were entrapped. Tyrosine (Tyr) was grafted onto poly(aspartic acid) (PASP) to produce PASP-Tyr, the following reaction between hyaluronic acid (HA) and ethylenediamine (EDA) modified PASP-Tyr formed the nanocarrier HA-EDA-PASP-Tyr (HEPT), and the loading capacity was up to 50.9 ± 4.3% for CUR and 26.0 ± 1.9% for DOX. The spherical HEPT with the mean particle size of 142.9 ± 11.4 nm expanded and deformed into petaloid pattern with an increased size of about 2 µm when triggered by the acidic microenvironment. In vitro anticancer activity evaluation revealed that the co-loaded (DOX+CUR)@HEPT nanoparticles presented higher cytotoxicity against HCT-116 cells compared with that of the free combination of (DOX+CUR). Confocal laser scanning microscopy observation indicated that HEPT carrier promoted cellular uptake of drugs by means of active targeting capacity of HA ligand. With high loading capacity and tailored carrier structure, the nanoparticles formulations may offer a new strategy for cancer treatment.
研究领域:
药剂学
·
肿瘤学
·
生物材料
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产品关联
DOI
PubMed
高影响因子
Asian Journal of Organic Chemistry
·
2017
·Vol. 6
·期 10
·1385-1389
·
IF 2.788
Kui Wang,Jian-Hua Cui,Si-Yang Xing,Xiao-Wei Ren
Graphical I recall you ! Highly selective recognition of acidic amino acids, such as glutamic acid and aspartic acid, by a positively charged calixpyridinium is reported. Highly selective recognition of acidic amino acids, such as glutamic acid and aspartic acid, by a positively charged calixpyridinium is reported. The complexation behavior of the calixpyridinium host towards a dipeptide containing the glutamic acid residue and a glutamic acid metabolite is also described.
研究领域:
生物化学
·
分子识别
·
有机化学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2014
·Vol. 38
·期 10
·4791-4798
·
IF 3.159
Xu Zhao,Ruisong Wei,Ligong Chen,Di Jin,Xilong Yan
A glucosamine modified near-infrared cyanine fluorescent probe has been synthesized and developed as an efficient and visual sensor for the trace level determination of glutamic acid (Glu) and aspartic acid (Asp) with no interference by other amino acids. A prominent fluorescence enhancement at 805 nm and a remarkable color change from pale red to colorless were observed in the presence of Glu and Asp respectively. This probe may also serve as a highly sensitive acidic pH probe with a pKa value of 5.82. Furthermore, the chemosensor has been successfully applied for the imaging of Glu and Asp in living cells, and the cytotoxicity assay exhibited that it is of low toxicity under the experimental conditions.
研究领域:
生物化学
·
分析化学
·
医学
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产品关联
DOI
高影响因子
JOURNAL OF FOOD ENGINEERING
·
2023
·
IF 5.5
Hui-min Yan,Yu Song,Man-man Yu,Xiu-ning Yao,Wen-wen Zhang,Ying Xu,Xue-qing Li,Yu-qin Xu,Shun Fang,Jun Qi,Guo-yuan Xiong,Chao Li,Jing-min Jia,Yong Hu
The purpose of this study was to use the complexes of gelatin (GA), positively charged arginine (Arg), and negatively charged aspartic acid (Asp) to produce a stable o/w emulsion using a low-energy stirring method. The thermal stability mechanism of this emulsion was investigated by evaluating its particle size, microstructure, differential scanning calorimetry (DSC), rheology, and ζ potential , as well as the secondary structure, surface hydrophobicity, and interaction force of gelatin-amino acid complexes. The results showed that adding Arg and/or Asp significantly decreased the particle size of the emulsion (P < 0.05). Particularly, the emulsion stabilized by gelatin-Arg-Asp showed the smallest particle size of 0.9 μm (D3.2), the highest absolute zeta potential (21.58 mV), the greatest viscosity, and the highest thermal stability. Even after heating at 121 °C for 20 min, this emulsion still had smaller particles than the unheated emulsion with or without Arg or Asp. Asp and Arg enhanced the triple helix content of gelatin through intramolecular hydrogen bonds and protected the surface hydrophobic groups of gelatins through intermolecular hydrophobic interactions of guanidine groups, increasing the depolymerization and ordered structure of gelatin and thus prolonging the temperature corresponding to the endothermic peak from 24.16 °C to 84.35 °C. These findings should contribute to the high thermal stability of the gelatin-Arg-Asp-stabilized emulsion. This study suggested that macromolecular protein-stabilized oil-in-water emulsions with a low oil phase content could be prepared by low-energy emulsification .
研究领域:
食品科学
·
生物化学
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DOI
高影响因子
危险品化学品经营许可证（带存储）