Copper-based ternary bimetal chalcogenides have very promising potential as multifunctional theragnosis nanoplatform for photothermal treatment of tumors. However, the design and synthesis of such an effective platform remains challenging. Herein, hydrophilic CuCo2S4 nanocrystals (NCs) with a desirable size of ~10 nm were synthesized by a simple one-pot hydrothermal route. The as-prepared ultrasmall CuCo2S4 NCs show: 1) intense near-infrared (NIR) absorption, which is attributed to 3d-electronic transitions from the valence band (VB) to an intermediate band (IB), as identified by Density Functional Theory (DFT) calculations; 2) high photothermal performance with a photothermal conversion efficiency up to 73.4%; and 3) capability for magnetic resonance (MR) imaging, as a result of the unpaired 3d electrons of cobalt. Finally, we, for the first time, demonstrated that the CuCo2S4 NCs are a promising "all-in-one" photothermal theragnosis nanoplatform for photothermal cancer therapy under the irradiation of a 915 nm laser at a safe power density of 0.5 W cm-2 , guided by MR and infrared thermal imaging. Our work further promotes the potential applications of ternary bimetal chalcogenides for photothermal theragnosis therapy. B. Li, F. K. Yuan and G. J. He contributed equally to this work. The authors acknowledge our membership of the UK's HPC Materials Chemistry Consortium, which is funded by Engineering and Physical Sciences Research Council (EP/L000202). The authors would thank the use of the UCL Legion High Performance Computing Facility and associated support services, in the completion of this work.
An all-fiber ratiometric wavelength monitor for optical wavelength measurement is proposed and is investigated theoretically and experimentally. Two edge filters with opposite slope spectral responses based on singlemode-multimode-singlemode (SMS) fiber structures are developed. A ratiometric wavelength measurement system employing the developed SMS edge filters demonstrates a high discrimination range of 20.41 dB and a potential wavelength measurement resolution of 10 pm over a wavelength range from 1530 to 1560 nm.
IntroductionA wavelength monitor is a key component for many optical systems such as multi-channel dense wavelength-division multiplexing (DWDM) optical communication systems and fibre Bragg grating (FBG) based optical sensing systems. A FBG-based optical sensing system requires a wavelength demodulation system capable of accurately estimating the wavelength shift in the reflected light from an FBG element induced by strain or temperature changes.Wavelength measurement or monitoring can be implemented using a ratiometric power measurement technique. A ratiometric wavelength monitor usually consists of a splitter with two outputs to which are attached an edge filter arm with a well defined spectral response and a reference arm. Alternatively, two edge filters arms with opposite slope spectral responses can be used. The use of two opposite slope edge filters can increase resolution of the ratiometric system [1]. Such a ratiometric wavelength monitor scheme converts the wavelength measurement into a signal intensity measurement. Compared with a wavelength-scanning-based active measurement scheme, it has the advantages of a simple configuration, the potential for high-speed measurement and the absence of mechanical movement. The main element of the ratiometric scheme, the edge filter, can be implemented by either a bulk thin filter [1], a fiber grating [2], biconical fiber couplers [3], or a bending fiber [4,5]. An all-fiber edge filter has several advantages by comparison to bulk filters, for example, ease of interconnection, mechanical stability and low polarization sensitivity [6].Singlemode-multimode and singlemode-multimode-singlemode (SMS) fiber structures have been investigated for use in several applications e.g. a fiber lens, a displacement sensor, a refractometer, a bandpass filter and an edge filter [7][8][9][10][11]. Based on our previous investigation [11], this paper proposes and demonstrates a ratiometric wavelength monitor using two edge filters consisting of SMS fiber structures with opposite slope spectral responses. This configuration has the advantage that it can achieve opposite slope spectral responses with a high
Lysozyme crystals in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim]BF(4)), 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl), 1-butyl-3-methylimidazolium bromide([C(4)mim]Br), and 1,3-dimethylimidazolium iodine([dmim]I) were prepared, and the influence of ionic liquids (ILs) on the structure and activity change of lysozyme was investigated. Fourier transform infrared spectroscopy revealed the major secondary structures of α-helix and β-sheet for lysozyme. It was interesting to note that increases of the band near 2,935 and 1,656 cm(-1) from Raman spectroscopy are attributed to the unfolding of lysozyme molecules. A shift in amide III from 1,230 to 1,270 cm(-1) in adding [dmim]I occurs, indicating a transformation from β-sheet to random coil. With regard to adding [C(4)mim]BF(4), [C(4)mim]Cl, and [C(4)mim]Br, α-helix and β-sheet are the predominant structures for lysozyme. The activity study showed that the ILs used brought a positive effect. Especially, [dmim]I leads to a drastic increase in relative activity, and its value reaches 50 %.
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