Preparation of N-doped carbon dots based on starch and their application in white LED

N-doped carbon dots (CDs) were synthesized simply and economically by a one-step hydrothermal method using starch as a carbon source and ethylenediamine (EDA) as a nitrogen dopant. The prepared CDs possess the properties of excitation-wavelength dependence and emit blue fluorescence under the excitation wavelength of 365 nm. CDs/starch composite was prepared to achieve the solid-state emission of CDs and their application in light emitting diode (LED) as fluorescent materials. White LED, with CIE coordinates of (0.33, 0.37) and correlated color temperature of 5462 K, was obtained by combining CDs/starch and ultraviolet LED light source, indicating that starch-based CDs have the promising potential in the field of optoelectronic devicesPeer reviewe

The effects of surface modifications of multiwalled carbon nanotubes on their dispersibility in different solvents and poly(ether ether ketone)

The effects of surface modifications of multi-walled carbon nanotubes (MWCNTs) on their dispersibility in different solvents and poly (ether ether ketone) (PEEK) have been studied. MWCNTs were treated by mixed acids to obtain acid-functionalized MWCNTs. The acid-functionalized MWCNTs were modified with different chemical agents separately, such as 1,6-diaminohexane, hexadecyl trimethyl ammonium bromide, silane coupling agent 3-aminopropyltriethoxysilane, anhydrous sulfanilic acid and ethanolamine. MWCNT/PEEK composite films were fabricated in order to explore systematically the dispersibility of differently modified MWCNTs PEEK as well as in different solvents. The morphology and structures of MWCNTs and the compatibility between MWCNTs and PEEK have been investigated. It was observed that the MWCNTs modified with anhydrous sulfanilic acid have an excellent dispersion in the PEEK grafted by sulfonic acid groups and that the MWCNTs modified with ethanolamine are also dispersed well in pure PEEK. The results herein provide useful insights into the development of MWCNT/PEEK composites for a wide variety of applications.Peer reviewe

Applications of Phosphotyrosine Superbinding SH2 Domain Variants

Protein tyrosine kinases (PTKs, or TKs) have emerged as one of the most intensively pursued targets in the development of anti-cancer therapeutics, due to their critical roles in the phosphotyrosine (pTyr)-mediated signaling network that regulates many cancer-related cellular activities. The TKs, tyrosine phosphorylation phosphatases (PTPs) and pTyr recognition SH2 proteins are intensively tyrosine phosphorylated, which play a pivotal role in determining the signaling outcome of this network. More than 50% of all human proteins are tyrosine phosphorylated and many of these TK substrates have been proven functional in TK regulated cellular activities. Therefore, proteomics studies of tyrosine phosphorylation are of great value for expanding our understanding of this network and its role in tumorigenesis. Taking advantage an engineered SH2 domain with superb pTyr binding affinity, an SH2-affinity purification mass spectrometry (SH2-AP-MS) assay was developed and optimized for global TK status profiling by determining the abundance of functionally significant TK pTyr peptides including the activation loops. Multiple known TK biomarkers were identified by this assay from a minute amount of protein extracts from cultured cells or clinical leukemia or solid tumor samples. In the quantitative AP-MS study of cancer cells treated by targeted therapeutics, differential TK responses were monitored. The receptor c-Kit was found to be dramatically upregulated with long-term trastuzumab treatment which contributed to acquired trastuzumab resistance in the SK-BR-3 breast cancer cells. These results revealed the potential applications of SH2-AP-MS in the discovery of novel TK biomarkers and examination of TK positive cancers in the clinical setting. In addition, a SH2 superbinder modified yeast two hybrid (Y2H) system was developed that is potentially capable of identifying TK substrate in a high-precision and high-throughput manner. This system consisted of an SH2-superbinder-fused bait that greatly promoted the reporter gene readout, a TK substrate prey or cDNA library preys, and a co-expressed TK under the control of a conditional promoter that allowed for reverse screen to eliminate false positives. In a medium-scale cDNA library screening for Src kinase substrates, 94 positive colonies were isolated representing 48 unique in-frame proteins or protein fragments, of which at least 9 proteins are known Src substrates or direct Src interactors

An Efficient Synthesis and Photoelectric Properties of Green Carbon Quantum Dots with High Fluorescent Quantum Yield

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)To greatly improve the production quality and efficiency of carbon quantum dots (CQDs), and provide a new approach for the large-scale production of high-quality CQDs, green carbon quantum dots (g-CQDs) with high product yield (PY) and high fluorescent quantum yield (QY) were synthesized by an efficient one-step solvothermal method with 2,7-dihydroxynaphthalene as the carbon source and ethylenediamine as the nitrogen dopant in this study. The PY and QY of g-CQDs were optimised by adjusting reaction parameters such as an amount of added ethylenediamine, reaction temperature, and reaction duration. The results showed that the maximum PY and QY values of g-CQDs were achieved, which were 70.90% and 62.98%, respectively when the amount of added ethylenediamine, reaction temperature, and reaction duration were 4 mL, 180 °C, and 12 h, respectively. With the optimised QY value of g-CQDs, white light emitting diodes (white LEDs) were prepared by combining g-CQDs and blue chip. The colour rendering index of white LEDs reached 87, and the correlated colour temperature was 2520 K, which belongs to the warm white light area and is suitable for indoor lighting. These results indicate that g-CQDs have potential and wide application prospects in the field of white LEDs.Peer reviewedFinal Published versio

One-step hydrothermal synthesis of fluorescence carbon quantum dots with high product yield and quantum yield

A one-step hydrothermal synthesis of nitrogen and silicon co-doped fluorescence carbon quantum dots (N,Si-CQDs), from citric acid monohydrate and silane coupling agent KH-792 with a high product yield (PY) of 52.56% and high quantum yield (QY) of 97.32%, was developed. This greatly improves both the PY and QY of CQDs and provides a new approach for a large-scale production of high-quality CQDs. Furthermore, N,Si-CQDs were employed as phosphors without dispersants to fabricate white light-emitting diodes (WLEDs) with the color coordinates at (0.29, 0.32). It is suggested that N,Si-CQDs have great potential as promising fluorescent materials to be applied in WLEDs.Peer reviewe

Exploring multi-band excitations of interacting Bose gases in a 1D optical lattice by coherent scattering

We use a coherent Bragg diffraction method to impart an external momentum to ultracold bosonic atoms trapped in a one-dimensional optical lattice. This method is based on the application of a single light pulse, with conditions where scattering of photons can be resonantly amplified by the atomic density grating. An oscillatory behavior of the momentum distribution resulting from the time evolution in the lattice potential is then observed. By measuring the oscillating frequencies, we extract multi-band energy structures of single-particle excitations with zero pseudo-momentum transfer for a wide range of lattice depths. The excitation energy structures reveal the interaction effect through the whole range of lattice depth.Comment: 6 pages, 5 figure

The surface modifications of multi-walled carbon nanotubes for multi-walled carbon nanotube/poly (ether ether ketone) composites

This document is the Accepted Manuscript of the following article: Zongshuang Cao, Li Qiu, Yongzhen Yang, Yongkang Chen, and Xuguang Liu, ‘The surface modifications of multi-walled carbon nanotubes for multi-walled carbon nanotube/poly(ether ether ketone) composites’, Applied Surface Science, Vol. 353: 873-881, October 2015, DOI: https://doi.org/10.1016/j.apsusc.2015.07.025, made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).The effects of surface modifications of multi-walled carbon nanotubes (MWCNTs) on the morphology, dynamic mechanical and tribological properties of multi-walled carbon nanotube/poly(ether ether ketone) (MWCNT/PEEK) composites have been investigated. MWCNTs were treated with mixed acids to obtain acid-functionalized MWCNTs. Then the acid-functionalized MWCNTs were modified with ethanolamine (named e-MWCNTs). The MWCNT/PEEK composites were prepared by a solution-blending method. A more homogeneous distribution of e-MWCNTs within the composites was found with scanning electron microscopy. Dynamic mechanical analysis demonstrated a clear increase in the storage modulus of e-MWCNT/PEEK composites because of the improved interfacial adhesion strength between e-MWCNTs and PEEK. Furthermore, the presence of e-MWCNTs caused an enhancement in the glass transition temperature of the composites. Wear tests have shown that the friction coefficient of e-MWCNT/PEEK composites decreased significantly during the test after the running-in period. This suggests that there is an obvious improvement in tribological properties of e-MWCNT/PEEK composites. Overall, the e-MWCNT/PEEK composites have exhibited improved properties and are promising for their applications in industry.Peer reviewe