ABSTRACT
Hyper cross-linked polymers (HCPs), as a key precursor of hard carbon (HC) anode materials, stand out because of their capacity for molecular-scale structural design and comparatively straightforward preparation techniques, which are not seen in other porous materials synthesized procedure. A novel synthesis method of HCPs is developed in this paper, which is through the incorporation of functional macromolecules, the structural control and heteroatom doping of the product has been achieved, thus augmenting its electrochemical performance in batteries. In this work, carbonized tetraphenylporphyrin zinc (TPP-Zn) doped HCP-based hard carbon (CTHCP) with stable structure was prepared by Friedel-Crafts reaction and carbonization by using naphthalene and trace TPP-Zn as monomers, dimethoxybenzene (DMB) as crosslinking agent and FeCl3 as catalyst. The introduction of TPP-Zn, a functional macromolecule with unique two-dimensional structure, realized the pore structure regulation and N doping of the raw carbonized HCP-based hard carbon (CHCP). The results showed that CTHCP had higher mesoporous volume, N content and wider layer spacing than CHCP. In addition, CTHCP anode exhibited excellent Li+/Na+ storage performance, initial reversible capacity, rate performance and long cycle life. More amount of N-containing (N-5) active sites and mesoporous content in CTHCP anode was the main reason for the improvement of Na+ storage effect. While the increased interlayer spacing had a greater effect on the lithium storage capacity. This study uncovered the design rules of HC anode materials suitable for Li+/Na+ batteries and provided a new idea for the preparation of high-performance HC anode materials.
ABSTRACT
AIM: Construct prokaryotic expression vector carrying mouse TRBP (TAR RNA-binding protein) gene and test the double-stranded RNA binding ability of TRBP. METHODS: RT-PCR was used to obtain TRBP cDNA from mouse genomic DNA. Then, we built the His-tag fusion expression vector of TRBP and transformed it into E.coli BL21(DE3). Ni-NTA beads were used to isolate and purify the recombinant protein and vitro transcription was used to get Pre-miR-122. Finally, SDS-PAGE and ITC (isothermal titration calorimetry) assay were both used to validate TRBP's binding ability with Pre-miR-122. RESULTS: We purified the recombinant protein TRBP whose molecular weight is 32.4 kDa. The purified bioactive TRBP protein binding on NI-NTA beads showed that it had a strong binding capacity on Pre-miR-122. CONCLUSION: We constructed TRBP prokaryotic expression system successfully and studied the double-stranded RNA binding ability of TRBP preliminarily.
Subject(s)
RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Animals , Cloning, Molecular , Escherichia coli/genetics , Escherichia coli/metabolism , Mice , MicroRNAs/metabolism , Protein Binding , RNA-Binding Proteins/isolation & purification , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/isolation & purification , Recombinant Fusion Proteins/metabolismABSTRACT
OBJECTIVE: To prepare curcumin nanoparticles and evaluate the in vitro release of curcumin. METHODS: The chitosan-graft-vinyl acetate copolymers were synthesized by free radical polymerization. Curcumin nanoparticles were synthesized by ultrasonic irradiation. The encapsulation efficiency of the nanoparticles and the in vitro release of curcumin were studied. RESULTS: The nanoparticles were discrete and uniform spheres, covered with positive charges. The encapsulation efficiency of nanoparticles was up to 91.6%. The in vitro release profile showed the slower release rate of curcumin. CONCLUSION: The methods is simple. The nanoparticles possess good physical performance and sustained release character in vitro.
Subject(s)
Chitosan/chemistry , Curcuma/chemistry , Curcumin/isolation & purification , Drug Delivery Systems , Technology, Pharmaceutical/methods , Chemistry, Pharmaceutical , Nanoparticles/chemistry , Plants, Medicinal/chemistry , Polymers/chemistry , UltrasonicsABSTRACT
Strong terahertz (1 THz= 10(12) Hz) radiation can be generated by the electron oscillation in fs-laser-induced wake fields. The interaction of a fs-laser pulse with a low-density plasma layer is studied in detail using numerical simulations. The spatial distribution and temporal evolution of terahertz electron current developed in a low-density plasma layer are presented, which enables us to calculate the intensity distribution of THz radiation. It is shown that laser and plasma parameters, such as laser intensity, pulse width, and background plasma density, are of key importance to the process. The optimum condition for wake-field excitation and terahertz emission is discussed upon the simulation results. Radiation peaked at 6.4 THz, with 900 fs duration and 9% bandwidth, can be generated in a plasma of density 5x 10(17) cm(-3) . It turns out that the maximum radiation intensity scales as n(3)(0) a(4)(0) when wake field is resonantly excited, where n(0) and a(0) are, respectively, the plasma density and the normalized field amplitude of the laser pulse.
