Engineered spidroin-derived high-performance fibers for diverse applications

Spider silks are well known for their exceptional mechanical properties that are tougher than Kevlar and steel.However,the restricted production amounts from their native sources limit applications of spider silks.Over the decades,there have been significant interests in fabricating man-made silk fibers with comparable performance to natural silks,inspiring many efforts both for biosynthesizing recombinant spider silk proteins(spidroins)in amenable heterologous hosts and biomimetic spinning of artificial spider silks.These strategies provide promising routes to produce high-performance and functionally optimized fibers with diverse applications.Herein,we summarize the hosts that have been applied to produce recombinant spidroins.In addition,the fabrication and mechanical properties of recombinant spidroin fibers and their composite fibers are also introduced.Furthermore,we demonstrate the applications of recombinant spidroin-based fibers.Finally,facing the challenges in biosynthesis,scalable production,and hierarchical assembly of high-performance recombinant spidroins,we give a summary and perspective on future development.

Detection of Enterocin Gene from Enterococcus

[ Objective] This study aimed to clone and identify enterocin gene from Enterococcus. [ Method] The genomic DNA of 12 enterocecci was extracted, and separately amplified with specific primers. The amplified fragments were ligated into PGEM-T Easy vector, which was then transformed into DH5α competent cells. The positive clones were sequenced. [Result] Enterocin A gene was 274 bp long. It was obtained from six enterococci, and the amino acids encoded by the enterocin genes cloned from five object enterocecci were the same as that of type IIa reference strains except only one amino acid. The homology among them reached 99.76 - 100%, suggesting that the bacteriocin isolated from the enterococcis belonged to type II. Structure prediction by DNAstar indicated that 22nd - 30th amino acids of enterocin A formed ot region, which had a hydrophilic region at its N-terminal and a hydrophobic region at its C-terminal, a transmembrane helix structure. [ Conclusion] This study will provide basis for the heterologous expression and applications of enterocins. Key words Enterocin gene; Enterocecci; PCR; Sequence analysis

Photovoltaic efficiency enhancement of polycrystalline silicon solar cells by a highly stable luminescent film

Si-based solar cells have dominated the entire photovoltaic market,but remain suffering from low power conversion efficiency(PCE),partly because of the poor utilization of ultraviolet(UV)light.Europium(III)(Eu^3+)complexes with organic ligands are capable of converting UV light into strong visible light,which makes them ideal light converter to increase the efficiency of solar cells.However,the low stability of such complexes seriously hampers their practical applications.In this work,we report a highly stable and luminescent ethylene-vinyl acetate(EVA)copolymer film consisting of a Eu^3+complex as a down-shift material,Eu(ND)4 CTAC(ND=4-hydroxy-2-methyl-1,5-naphthyridine-3-carbonitrile,CTAC=hexadecyl trimethyl ammonium chloride),coating of which onto the surface of large area polycrystalline silicon solar cells(active area:110 cm^2)results in an increase of PCE from 15.06%to 15.57%.Remarkable stability of the luminescent film was also demonstrated under lightsoaking test for 500 h,and no obvious luminescence degradation can be observed.The remarkable enhancement of the conversion efficiency by 0.51%absolute on such a large active area,together with the high stability of the luminescent film,demonstrates a prospect for the implementation of the films in photovoltaic industry.

Tunable white-light emission of lanthanide(Ⅲ) hybrid material based on hectorite

In this work, we present novel trivalent lanthanide ions（Ln^3＋）-based luminescent hybrid materials, in which the organic ligands are covalently grafted on the hectorite templates and the Ln^3＋ ions can be well immobilized by the ligands through coordination bond. The hybrid materials exhibit tunable emission colors by varying the molar ratio of Eu^3＋ to Tb^3＋, and the one with Eu^3＋：Tb^3＋=1：1 exhibits excellent coordinate of（0.327, 0.328） located in the ＂white region＂ of the CIE 1931 chromaticity diagram（under300 nm UV illumination）. These properties make the hybrid composites suitable for fabricating optoelectronic devices such as full-color displays and white LED.

A stimuli responsive lanthanide-based hydrogel possessing tunable luminescence by efficient energy transfer pathways

Energy transfer as an important component in light-harvesting antenna systems can mimic effectively natural photosynthesis processes,showing great potential in optoelectronic devices.Herein,we report a responsive polymeric hydrogel based on the combination of excited state intramolecular proton transfer(ESIPT) molecule(Salicylic acid,Sal) and terbium(Ⅲ)(Tb^(3+)),as enabled by external stimuli to construct artificial light-harvesting antenna systems.Benefiting from unique photophysical properties of Sal,the synthesized hydrogel displays a temperature-dependent reversible opaque?transparent states transition,accompanied with an interesting photoluminescence behavior.Moreover,by further incorporating europium(Ⅲ)(Eu^(3+)) into the hydrogel,we demonstrate well-defined cascades of energy transfer that provides a tunable optical output from the collection of lanthanides by the excitation of a common sensitizer(Sal) upon base vapor stimulation.Efficient energy transfer efficiency from Tb^(3+) to Eu^(3+),as high as 97.8%,was also obtained as established by the time-resolved fluorescence spectroscopy analysis.

Recent progress in luminescent materials based on lanthanide complexes intercalated synthetic clays

Interest in lanthanide complexes in the synthetic clays remains growing considerably during the last decades because of the attractive features of the individuals. Synthetic clays like Laponite~? and Aminoclay show great potentials in building up the luminescent hybrid materials due to their obvious advantages such as high purity, high dispersibility(or solubility) in water to yield translucent gels and clear aqueous solution. Additionally, their strong adsorption capacity for non-polar molecules or complexes is favorable to the formation of water-soluble and aqueous processable luminescent materials. This feature article summarizes the latest developments in the design and preparation of highly luminescent organicinorganic hybrid materials with excellent aqueous process ability based on lanthanide complexes intercalated synthetic clays.

Aminoclay decorated with lanthanide complexes and carbon dots:Tunable emission and information encryption

Herein we present emission color-tunable and multi-functional lanthanide(Ⅲ)luminescent hybrid materials(Ln(DPA)@AC-CDs)by mixing aminoclay(AC),2,6-pyridinedicarboxylic acid(DPA),Ln3+(Ln=Eu,Tb or Eu and Tb in different molar ratios),and carbon dots(N,S-CDs)in water,showing high quantum yields up to 58.8%.The emission colors can be finely tuned by altering the excitation wavelength and the amounts of the components,and white light emission(CIE-(0.27,0.25))can be achieved for sample Eu1Tb2(DPA)@AC-CDs under 325 nm light irradiation.In addition,under 365 nm UV light excitation,the Eu(DPA)@AC-CDs powder exhibits red luminescence due to the sensitization effect of N,S-CDs on Eu^3+,which turns to bright blue when the powder is dispersed in water attributed to the high dispersion of the aggregated N,S-CDs particles.These luminescent properties afford Ln(DPA)@AC-CDs potential candidates for designing optoelectronic devices like WLEDs or in information encryption applications.

坚持就是胜利吗?创业坚持的研究述评与展望

创业坚持是创业过程中的重要内容。尽管近几年国内学者对创业坚持的关注度逐渐升温,但仍处于起步阶段。本文在回顾国内外文献的基础上,首先,从逆境与挫折、外部机会视角阐明了创业坚持的内涵,并辨析了其与毅力、创业韧性的区别;其次,从创业者、企业和外部环境三个层面梳理了创业坚持的影响因素和影响过程;最后,从理性与非理性视角出发,指出创业坚持是一把双刃剑,在提高创业者的工作满意度和财富收入,以及促进企业创建、成长和企业绩效的同时,也可能引发遗憾和工作-家庭冲突。在此基础上,针对当前研究存在的不足与缺陷,提出未来研究应该从创业坚持的测量、影响因素、结果变量、边界条件、跨文化研究等方向做进一步探索。