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The turn-off fluorescent photoswitches for information encryption are constantly being developed. However, there are no reports about time-switchable (fluorescence lifetime-switchable) encryption to overcome the limitations of tunable encoding numbers in spectrally and temporally encoded libraries. Based on the double-exponential fitting of fluorescence lifetime, we propose, a fatigue-free and highly flexible switch between the amplitude-weighted average fluorescence lifetime (τm) and the intensity-weighted average fluorescence lifetime (τi), which will realize the supermultiplexed fluorescence lifetime switchable encryption. The potentially enormous library of different fluorescent lifetime combinations would facilitate the development of information security.

Asymmetric, multilevel, switchable, and reversible encryption is realized by algorithm encryption, which plays an important role in encryption technology. Fluorescence lifetime encryption is currently not executed by an algorithm. It is well-known that the short fluorescence lifetime (τ1), long fluorescence lifetime (τ2), amplitude-weighted average fluorescence lifetime (τm), and intensity-weighted average fluorescence lifetime (τi) can be obtained using a double exponential fitting, and then these four lifetime parameters can be considered as four lifetime algorithms. Therefore, we propose that the acquisition of these four fluorescence lifetimes can be regarded as further dividing the lifetime by different algorithms and optimizing lifetime multiplexing. Moreover, the four lifetime algorithms of τ1, τm, τ2, and τi can be switched between each other and can be used to perform asymmetric, multilevel, and reversible lifetime encryption to effectively increase the difficulties of anticounterfeiting.

The utilization of solar energy to produce hydrogen from water is showing increased importance and desirability in the field of artificial photosynthesis to produce clean and sustainable fuels. In a typical three-component dye-sensitized semiconductor system for photocatalysis, the dye sensitizer plays an essential role of energy antenna for harvesting visible light and promoting the reduction reaction to generate hydrogen. In recent decades, a lot of attention has focused on metal-free organic sensitizers, which have the advantages of low cost, high molar extinction coefficient, good modifiability and, most importantly, ability to avoid the use of noble metal ions. This Review enumerates the design strategies, specific properties and photocatalytic performances of metal-free sensitizers in the past 30 years and concludes their evolution process. The advantages of different types of metal-free sensitizers are highlighted and the instructively enlightening experiences are systematic summarized.

Background Human hepatocellular carcinoma (HCC) lacks effective curative therapy and there is an urgent need to develop a novel molecular-targeted therapy for HCC. Selective tyrosine kinase inhibitors have shown promise in treating cancers including HCC. Tyrosine kinases c-Met and Trks are potential therapeutic targets of HCC and strategies to interrupt c-Met and Trks cross-signaling may result in increased effects on HCC inhibition. Methods The effects of Indo5 on c-Met and Trks activity were determined with in vitro kinase activity assay, cell-based signaling pathway activation, and kinases-driven cell transformation. The in vivo anti-tumor activity was determined with xenograft mice and liver orthotopic mice models. The co-expression of c-Met and TrkB in 180 pairs of HCC and adjacent normal tissues were detected using immunohistochemical staining. Results Indo5, a novel lead compound displayed biochemical potency against both c-Met and Trks with selectivity over 13 human kinases. Indo5 abrogated HGF-induced c-Met signaling activation and BDNF/NGF-induced Trks signal activation, c-Met or TrkB-mediated cell transformation and migration. Furthermore, Indo5 significantly decreased the growth of HCC cells in xenograft mice and improved the survival of mice with liver orthotopic tumors. In addition, co-expression of c-Met and TrkB in HCC patients was a predictor of poor prognosis, and combined inhibition of c-Met and TrkB exerted a synergistic suppressive effect on HCC. Conclusions These findings indicate that Indo5 is associated with marked suppression of c-Met and Trks co-expressing HCC, supporting its clinical development as an antitumor treatment for HCC patients with co-active c-Met and Trks signaling. Electronic supplementary material The online version of this article (10.1186/s13046-019-1104-4) contains supplementary material, which is available to authorized users.

Electricity price is crucial to the power system's reliability and economy, while long-term electricity prices can not avoid the deviation between the contracted electricity and the physical execution of electricity. Many electricity markets introduced on-demand spot prices to narrow the gap and balance power supply and demand. That will cause transmit electricity congestion due to users' unwillingness to accept higher prices. Previous works modeled the spot pricing auction process as a discrete multi-objective optimization problem according to auction rules with various costs and constraints. Most approaches ignored the users' sensitivity to reliability and price. Furtherly, the state space increases exponentially with the increases of users, which costs a long time to obtain stable convergence price and results in a negative price. We propose a deep reinforcement learning-based spot reliability pricing model that defines the balance as a state denotes price selection as action, and adopts the balance of supply and demand as a reward function. Besides that, we introduce users' sensitivity to reliability and price as penalty factors of the function. After comparing several reinforcement learning models' performance, we choose Policy-based Deep Q-Learning Networks (PDQN) to determine our reliability pricing strategy. Experiments show that the model ensures that spot prices converge to balance in 5 iterations and reduce the congestion rate by half compared to other methods.

In order to better investigate the working life of Smart Meter and discover in advance the possible faults existed in the same batch, the operational data of Smart Meter in running state has to be analyzed so as to construct the prediction model of Smart Meter life. Firstly, we collect all the data from the running smart meters regarding the operational faults, maintenance management, and their application data from the Power Information Collection System; Secondly, we analyze the operational data in running state; Lastly, according to the advantages and disadvantages of the three reliability prediction methods (element stress method, reliability prediction method based on reliability test, and reliability prediction method based on reliability verification), we can protract the model that can reflect the life degradation characteristics and life prediction of smart meter.

The phasor approach to fluorescence lifetime imaging microscopy (FLIM) is used to identify different types of tissues from hematoxylin and eosin (HE) stained basal cell carcinoma (BCC) sections. The results suggest that working directly on the phasor space with the clustering assignment achieves immunofluorescence like simultaneous five or six-color imaging by using multiplexed fluorescence lifetimes of HE. The phase approach is of particular effectiveness for enhanced visualization of the abnormal morphology of a suspected nidus. Moreover, the phasor approach to HE FLIM data can determine the actual paths or the infiltrating trajectories of basophils and immune cells associated with the preneoplastic or neoplastic skin lesions. The integration of the phasor approach with routine histology proved its available value for skin cancer prevention and early detection. We therefore believe that the phasor analysis of HE tissue sections is an enhanced visualization tool with the potential to simplify the preparation process of special staining and serve as color contrast aided imaging in clinical pathological examination.

With the rapid development of life sciences, there is an increasing demand for intravital fluorescence imaging of small animals. However, large dimensions and limited working distances of objective lenses in traditional fluorescence microscopes have limited their imaging applications mostly to superficial tissues. To overcome these disadvantages, researchers have developed the graded-index (GRIN) probes with small diameters for imaging internal organs of small animals in a minimally invasive fashion. However, dynamic imaging based on GRIN lens has not been studied extensively. Here, this paper presented a fluorescence endoscopic imaging system based on GRIN lenses using one-photon and two-photon excitation. GRIN lenses with 1.15 mm diameter and 7.65 mm length were used in the system. The images were acquired by a compact laser scanning imaging system with a resonant galvo-mirror system to scan the laser beam and a photomultiplier tube (PMT) to detect fluorescence signals. Experimental results showed that this system using two-photon excitation could implement dynamic fluorescence microendoscopic imaging and monitor the movement of blood flow beneath the skin in anesthetized mice while producing images with higher contrast and signal to noise ratio (SNR) than those using one photon excitation. It would be a useful tool for studying biological processes of small animals or plants in vivo.

This paper analyzes the status quo in China regarding carbon emissions, and discusses challenges facing coal utilization in China. It concludes that the development of clean coal technology is an important means to realize low-carbon emissions in China. Using scenario analysis methodology, this paper presents quantitative analysis of the potential of clean coal technologies for carbon emission reductions in 2015 and 2020. The analysis indicates that high-efficiency combustion in industrial boilers and clean, highly efficient coal-fired power generation should serve as important factors for carbon emission reductions before 2020.

The aaviation kerosene is a practical candidate fuel for scramjet engine in the flight regimes of Mach number less than 8, in considerations of safety, economy and portable. In the present paper, the ignition characteristics of a scramjet combustor model fueled by aviation kerosene was experimentally investigated, using the resistance heating direct-connected supersonic combustion facility of Northwestern Polytechnical University. The inflow conditions at the direct-connected combustor entrance were specified as: the nominal Mach of 2.0, the total temperature of 870～930K and the total pressure of about 770kPa. Three combustor performance of difference ER were compared applied CFD simulated. The experimental result suggested that: the cavity design is a key problem for kerosene successful ignition is the combustor; That chooses appropriate gas-oil ratio could increased performance of combustor and kept isolator interfered by gas.

Metallic glass film of Prsub60/subAlsub10/subNisub10/subCusub20/subis proposed to be used as a resist of phase-change lithography (PCL). PCL is a mask-less lithography technology by using laser-direct-writing to create the intended nanopatterns. Thermal distribution in the PrAlNiCu film after exposure is calculated by finite element method (FEM). Thin films are exposed by continuous-wave laser and selective etched by nitric-acid solution, and the patterns are discerned by optical and atomic force microscope. The etching rate of as-deposited PrAlNiCu is thus nearly five times of the crystalline film. These results indicate that PrAlNiCu metallic glass film is a promising resist for phase-change lithography.

The layer structures of the esophageal and oral tissues were investigated by using spectral imaging technology based on two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG). Because spectral imaging technology allows a simultaneous record of both the spectra and image, it is capable of identifying the layered structures of the epithelial tissues, including the keratinizing layer, epithelial cell layer and stromal layer in the molecular level, which are strongly correlated to tissue pathology. All this work indicates that this technique has the potential to provide more accurate and comprehensive information for the early pathological diagnosis of tissues with the stratified squamous epithelia.

The aim of this study is to develop a novel technique for improving the intraoperative margin assessment of glioblastoma by examining the total extrinsic extracellular matrix (ECM) with eosin staining using fluorescence lifetime imaging microscopy (FLIM) and scale-invariant feature transform (SIFT) descriptor analysis. Pseudo-color FLIM images obviously exhibit ECM distributions, changes in sequential sections, and different regions of interest. Meanwhile, SIFT descriptors are first utilized for the discrimination of glioblastoma margins by matching similar ECM regions and extracting keypoint orientations from FLIM images obtained from a series of continuous slices. The findings indicate that FLIM imaging with SIFT analysis of the total ECM is a promising method for improving intraoperative diagnosis of frozen and surgically excised brain specimen sections.

Maskless phase-change lithographic technology is developed as a photoresist of phase-change materials. The controllable growth behavior of the crystallization region on an amorphous thin film of Ge 2 Sb 2 Te 5 (GST) irradiated by a laser beam is investigated; the GST thin film is deposited on a silicon substrate by the sputtering method. The results of a series of the experiments and the simulations all show that the width of a crystalline pattern is not only closely related to laser power and pulse duration, but also is apparently affected by the interactive area between the focused laser spot and thin film. The width maintains a nonlinear growth with the enhancement of the laser power until the thin film approaches melting, whereas it gradually reaches a constant value due to the local thermal equilibrium. This equilibrium makes the width irrelevant to the moving velocity with certain constraints when the laser works in continuous-wave mode. Within a defocus range of 15 μ m , the widths of the crystalline patterns are obtained in a broad range from 690 nm to 8.13 μ m under a 0.4-NA objective lens. By adjusting the defocus amount, some crystalline square patterns with expected widths in a wide range are fabricated, and the mean percentage error between the expected and fabricated widths is only 1.495%.

Indocyanine green-loaded mesoporous silica-coated gold nanorods (ICG-loaded Au@SiO2) were prepared for the dual capability of X-ray computed tomography (CT) and fluorescence imaging. X-ray CT scanning showed that ICG-loaded Au@SiO2 could provide significant contrast enhancement; Near-infrared fluorescence generated by the nanomaterial was present up to 12 h post intratumoral injection, thus enabling ICG-loaded Au@SiO2 to be used as a promising dual mode imaging contrast agent. Multiplexed images can be more easily obtained with this novel type of multimodal nanostructure compared with traditional contrast agents. The dual mode imaging probe has great potential for use in applications such as cancer targeting, molecular imaging in combination with radiotherapy, and photothermolysis.