MINERALS ENGINEERING
·
2024
·
IF 4.9
Yiwen Hu,Jieliang Wang,Zhao Cao,Xu Wu,Wenda Lu,Weiwei Wang,Wenli Liu
Bastnaesite is an important strategic resource. Since the calcium-bearing gangue minerals in the pulp can dissolve and release Ca 2+ ions, Ca 2+ ions and sodium silicate have a co-depression effect on bastnaesite flotation, which will affect the separation and purification of bastnaesite. In this study, the mechanism of eliminating the co-depression effect using ethylene diamine tetraacetic acid (EDTA) was studied by micro-flotation, bench-scale flotation, zeta potential, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM)–energy spectrometry (EDS), contact angle and DFT calculations measurements. Micro-flotation results show that the addition of EDTA can effectively eliminated the co-depresses effect of Ca 2+ ions and sodium silicate. Bench-scale flotation tests showed that a high-quality rare earth (REE) ore concentrate with higher grade and recovery (62.35 % and 62.08 %, respectively) could be enriched by adding EDTA. Zeta potential results show that the combination of Ca 2+ ions and EDTA than with Ca 2+ ions alone, the surface potential of bastnaesite was significantly negative. XPS shows that EDTA prevented Ca-SiO 3 precipitation between Ca 2+ ions and sodium silicate by complexing Ca 2+ ions, which hindered the adsorption of sodium silicate to bastnaesite. SEM-EDS show that the addition of EDTA between Ca 2+ ions and sodium silicate, Ca 2+ ions had desorbed from the bastnaesite surface. Density functional theory (DFT) calculation showed that the adsorption energy of EDTA and Ca 2+ ions was much smaller than that of sodium silicate and Ca 2+ ions and Ca 2+ ions and mineral surface.
研究领域:
矿物学
·
浮选化学
✓ 已验证
DOI
高影响因子
FEMS MICROBIOLOGY LETTERS
·
2014
·Vol. 357
·期 1
·99-103
·
IF 2.046
Wang Xian-Kun,Jin Jian-Ling
Streptomyces netropsis SD-07, the producer of novel polyene macrolide antifungal antibiotics, was isolated from soil. For the investigation of the functions of its biosynthesis genes and regulation mechanisms, a genetic operating system is necessary. In this study, we successfully transferred the plasmid DNA of pSET152 from the methylation deficient donor, Escherichia coli ET12567/pSET152/pUZ8002, to S. netropsis SD-07 by conjugation and evaluated the crucial factors influencing the conjugation frequency. Ca2+ ions in presence the conjugation media may increase the conjugation frequency by 1000–10 000 times than Ca2+ ions absence in the same conjugation media, and 10–100 time higher than Mg2+ ions. Similar results (increasing the conjugation frequency by 10–100 times when media containing 60 mM CaCl2) were also obtained from the conjugation between E. coli ET12567 and Streptomyces coelicolor, S. lavendulae, S. venezuelae, despite their conjugation media were different (MS, CM, GS). So, CaCl2 concentration is a crucial factor for increasing the conjugation frequency, and the suitable concentration may probably be 60 mM. In addition, synthetic medium containing a small amount of organic nitrogen source may benefit increasing the conjugation frequency. These findings could be valuable for the development of a practical method for achieving conjugation in other Streptomyces spp.
研究领域:
微生物学
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遗传学
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分子生物学
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Yayu Su,Xiaolei Li,Huiming Ji,Zhihao Zhao,Peng Zhang
The Ca 2+ -Mn 2+ doped LaAlO 3 was prepared by solid state reaction method, and the effects of different doping content of Ca 2+ and Mn 2+ ions on the infrared radiation properties of LaAlO 3 were investigated. The result showed that after doping Ca 2+ and Mn 2+ ions, the infrared radiation properties of LaAlO 3 significantly increased. When 40 mol% Ca 2+ and 50 mol% Mn 2+ ions were doped into LaAlO 3 , the average emissivity in the wavelength range of 1–22 µm was up to 0.90, which was higher than pure LaAlO 3 (0.71). The enhancement of infrared radiation properties of LaAlO 3 was mainly due to the decrease of band gap of LaAlO 3 , the increase of hole carriers absorption of energy, and the increase of lattice vibration absorption after doping Ca 2+ and Mn 2+ ions. Ca 2+ -Mn 2+ doped LaAlO 3 with high infrared radiation properties shows application prospect in the high temperature oxidation environment.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2024
·
IF 11
Jipeng Zhang,Xiaojun Zhang,Chongyang Zhu
The self-assembly behavior of proteins and peptides has been widely studied due to their ability to construct various nanostructures, such as nanotubes and nanofibrils. Understanding the self-assembly mechanism is of great significance for developing functional nanomaterials. Herein, we adopt a novel method to construct ovotransferrin (OVT) fibrils by subtilisin A hydrolysis and Ca 2+ ions induced self-assembly with mild reaction conditions. The kinetic process of OVT fibrils formation contains lag, growth, and plateau stage. During the growth stage, OVT peptides self-assemble into precursor structures, which undergo morphological changes of twisted ribbons, helical ribbons, and nanotubes, ultimately closing to form mature fibrils. Ca 2+ ions likely coordinate with the carboxyl groups of OVT peptides, aiding in the self-assembly process. And the secondary conformation is manifested as a β-sheet stacking. The mature OVT fibrils have distinct hollow and left-handed structures. Then OVT fibrils successfully encapsulate zeaxanthin (Zea) and improve its solubility and stability. Besides, OVT fibrils exhibit no in vitro cytotoxicity, and significantly reduce allergenicity to egg allergy patients compared to OVT. OVT fibrils delivery Zea into milk to develop Zea fortified dairy beverage and improve the viscosity of dairy beverage. OVT fibrils show a great potential as nutrient delivery and texture optimization for food application.
研究领域:
食品科学
·
纳米技术
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生物技术
·
营养学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2021
·
IF 4.089
Wenzhuo Zhu,Shuai Zhou,Jian Wang,Wen Sun,Jinxing Chen,Ming He
Natural soft materials can generate a reversible transition between soft and tough states triggered by environmental stimuli. Inspired by this, various synthetic hydrogels with dynamic reversible crosslinks are developed. In this study, a weak coordination-induced dynamic crosslinked hydrogel is successfully synthesized. High concentrations of Ca2+ ions are coordinated with acrylamide, which then catalyze ammonium persulfate decomposition for rapid polymerization to a polyacrylamide (PAAm)/Ca hydrogel at room temperature. The preassembled coordination provides sufficient crosslinks, accompanied by enhanced hydrogen bonding during dehydration, which together endows the gel with high mechanical properties. This weak coordinated crosslinked structure is affected by humidity, leading to a wide range of mechanical properties of the gel, with the tensile strength ranging from 44.2 kPa to 5.6 MPa, elastic modulus from 17.3 kPa to 2.2 MPa, and toughness from 312.3 kJ/m3 to 7.8 MJ/m3. Additionally, Ca2+ ions preferentially coordinate with amides in the hydration process, and the gel exhibits an abnormal hydration phenomenon under low humidity. The gel with high polymer content has a higher water loss ratio and volume shrinkage. On this basis, we design an asymmetric bilayer structure gel and realize the curling and stretching of leaves and petals. Interestingly, the bilayer gel exhibits reversible adhesion properties and the tearing energy is up to 3985.9 J/m2 under low humidity. This principle may provide ideas and inspiration for producing hydrogels with adjustable mechanical strength and develop a route to construct versatile stimulus-responsive materials.
研究领域:
材料科学
·
化学
·
生物材料
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Lanting Wei,Xiang Wang,Junjie Fu,Jian Yin,Jing Hu
The current therapy for muscle injury is facing challenges in tissue self-regeneration and function restoration, which declines steeply with age. Tissue engineering is a promising strategy for treating skeletal muscular disorders. Natural polysaccharides have great potential to support cell growth and attachment as tissue-engineered scaffolds. A three-dimensional (3D) porous hydrogel scaffold has been prepared based on the double network of natural polysaccharide sodium alginate (SA), chitosan (CS) and Ca 2+ ions through the freeze-drying process. The physical, mechanical, and biological properties of the CS/SA/Ca 2+ hydrogel scaffold can be controlled by adjusting the SA/CS ratio. The physically cross-linked double network hydrogel showed good biosafety, high stability and satisfactory degradation rate . When the CS/SA molar ratio was 1:1.2 (H-1.2 group), the pore size and compression modulus of the double network hydrogel were 104.06 ± 2.64 µm and 40.00 ± 2.52 kPa, respectively. The results of in vitro evaluation showed that the 3D structure of the CS/SA/Ca 2+ double network hydrogel could well support adhesion and proliferation of C2C12 murine myoblasts and porcine skeletal muscle stem cells. The best cell growth effect was achieved in the H-1.2 group. The physically cross-linked CS/SA/Ca 2+ double network hydrogel can be a promising printable material as the cell scaffold in applications of skeletal muscle tissue engineering.
研究领域:
组织工程
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生物材料
·
生物医学工程
·
细胞生物学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2022
·
IF 8.431
Shizhu Cheng,Feng Tan,Xuri Wu,Fan Dong,Jinghua Liu,Yan Wang,Hongxia Zhao
Proteins existed in aquatic environments strongly influence the transport, fate of nanomaterials due to the formation of protein-corona surrounding nanomaterials. To date, how do proteins affect the aggregation behaviors of MXene, a new family of two-dimensional materials, in aquatic environment remains unknown. Here the aggregation kinetics of MXene Ti 3 C 2 T x nanosheets in various electrolytes (NaCl, CaCl 2 and Na 2 SO 4 ) was investigated by time-resolved dynamic light scattering in absence or presence of bovine serum albumin (BSA). Results showed that BSA affected the aggregation of Ti 3 C 2 T x in a concentration-dependent manner. Addition of 3 mg/L BSA decreased the critical coagulation concentrations (CCCs) of Ti 3 C 2 T x about 1.6–2.1 times, showing obvious destabilization effect; while BSA greater than 30 mg/L created a high-protein environment covering Ti 3 C 2 T x , producing high spatial repulsion and enhancing the dispersibility of Ti 3 C 2 T x . Ca 2+ ions have greater effect on the aggregation of Ti 3 C 2 T x due to the larger surface charge and bridging effect. The interaction between Ti 3 C 2 T x and BSA followed Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, and mainly attributed to hydrogen bonding and van der Waals forces , while positively charged lysine and arginine in BSA might attract onto Ti 3 C 2 T x through electrostatic attraction. The interaction decreased the content of α -helix structure in BSA from 74.7% to 53.1%. Ti 3 C 2 T x easily suffered from aggregation and their long-distance transport seemed impossible in synthetic or natural waters. The present findings provided new insights for understanding the transfer and fate of this nanomaterial in aquatic environments.
研究领域:
环境科学
·
纳米技术
·
材料科学
·
胶体化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）