Accurate prediction of remaining useful life (RUL) has been a critical and challenging problem in the field of prognostics and health management (PHM), which aims to make decisions on which component ...needs to be replaced when. In this article, a novel deep neural network named convolution-based long short-term memory (CLSTM) network is proposed to predict the RUL of rotating machineries mining the in situ vibration data. Different from previous research that simply connects a convolutional neural network (CNN) to a long short-term memory (LSTM) network serially, the proposed network conducts convolutional operation on both the input-to-state and state-to-state transitions of the LSTM, which contains both time-frequency and temporal information of signals, not only preserving the advantages of LSTM, but also incorporating time-frequency features. The convolutional structure in the LSTM has the ability to capture long-term dependencies and extract features from the time-frequency domain at the same time. By stacking the multiple CLSTM layer-by-layer and forming an encoding-forecasting architecture, the deep learning model is established for RUL prediction in this article. Run-to-failure tests on bearings are conducted, and vibration responses are collected. Using the proposed algorithm, RUL is predicted, and as a comparison, the performance from other methods, including deep CNNs and deep LSTM, is evaluated using the same dataset. The comparative study indicates that the proposed CLSTM network outperforms the current deep learning algorithms in URL prediction and system prognosis with respect to better accuracy and computation efficiency.
Commercial carbazole has been widely used to synthesize organic functional materials that have led to recent breakthroughs in ultralong organic phosphorescence
, thermally activated delayed ...fluorescence
, organic luminescent radicals
and organic semiconductor lasers
. However, the impact of low-concentration isomeric impurities present within commercial batches on the properties of the synthesized molecules requires further analysis. Here, we have synthesized highly pure carbazole and observed that its fluorescence is blueshifted by 54 nm with respect to commercial samples and its room-temperature ultralong phosphorescence almost disappears
. We discover that such differences are due to the presence of a carbazole isomeric impurity in commercial carbazole sources, with concentrations <0.5 mol%. Ten representative carbazole derivatives synthesized from the highly pure carbazole failed to show the ultralong phosphorescence reported in the literature
. However, the phosphorescence was recovered by adding 0.1 mol% isomers, which act as charge traps. Investigating the role of the isomers may therefore provide alternative insights into the mechanisms behind ultralong organic phosphorescence
.
Ultralong organic phosphorescence (UOP) has attracted increasing attention due to its potential applications in optoelectronics, bioelectronics, and security protection. However, achieving UOP with ...high quantum efficiency (QE) over 20 % is still full of challenges due to intersystem crossing (ISC) and fast non‐radiative transitions in organic molecules. Here, we present a novel strategy to enhance the QE of UOP materials by modulating intramolecular halogen bonding via structural isomerism. The QE of CzS2Br reaches up to 52.10 %, which is the highest afterglow efficiency reported so far. The crucial reason for the extraordinary QE is intramolecular halogen bonding, which can not only effectively enhance ISC by promoting spin–orbit coupling, but also greatly confine motions of excited molecules to restrict non‐radiative pathways. This work provides a reasonable strategy to develop highly efficient UOP materials for practical applications.
Intramolecular halogen bonding promotes the intersystem crossing rate in organic molecules and enhances the afterglow efficiency up to 52.1 %. This is the highest value achieved in molecular crystals reported so far.
Vibration-based Structural Health Monitoring (SHM) techniques are among the most common approaches for structural damage identification. The presence of damage in structures may be identified by ...monitoring the changes in dynamic behavior subject to external loading, and is typically performed by using experimental modal analysis (EMA) or operational modal analysis (OMA). These tools for SHM normally require a limited number of physically attached transducers (e.g. accelerometers) in order to record the response of the structure for further analysis. Signal conditioners, wires, wireless receivers and a data acquisition system (DAQ) are also typical components of traditional sensing systems used in vibration-based SHM. However, instrumentation of lightweight structures with contact sensors such as accelerometers may induce mass-loading effects, and for large-scale structures, the instrumentation is labor intensive and time consuming. Achieving high spatial measurement resolution for a large-scale structure is not always feasible while working with traditional contact sensors, and there is also the potential for a lack of reliability associated with fixed contact sensors in outliving the life-span of the host structure. Among the state-of-the-art non-contact measurements, digital video cameras are able to rapidly collect high-density spatial information from structures remotely. In this paper, the subtle motions from recorded video (i.e. a sequence of images) are extracted by means of Phase-based Motion Estimation (PME) and the extracted information is used to conduct damage identification on a 2.3-m long Skystream® wind turbine blade (WTB). The PME and phased-based motion magnification approach estimates the structural motion from the captured sequence of images for both a baseline and damaged test cases on a wind turbine blade. Operational deflection shapes of the test articles are also quantified and compared for the baseline and damaged states. In addition, having proper lighting while working with high-speed cameras can be an issue, therefore image enhancement and contrast manipulation has also been performed to enhance the raw images. Ultimately, the extracted resonant frequencies and operational deflection shapes are used to detect the presence of damage, demonstrating the feasibility of implementing non-contact video measurements to perform realistic structural damage detection.
In view of the multiple pathological hallmarks of tumors, nanosystems for the sequential delivery of various drugs whose targets are separately located inside and outside tumor cells are desired for ...improved cancer therapy. However, current sequential delivery is mainly achieved through enzyme‐ or acid‐dependent degradation of the nanocarrier, which would be influenced by the heterogeneous tumor microenvironment, and unloading efficiency of the drug acting on the target outside tumor cells is usually unsatisfactory. Here, a light‐triggered sequential delivery strategy based on a liposomal formulation of doxorubicin (DOX)‐loaded small‐sized polymeric nanoparticles (DOX‐NP) and free sunitinib in the aqueous cavity, is developed. The liposomal membrane is doped with photosensitizer porphyrin–phospholipid (PoP) and hybridized with red blood cell membrane to confer biomimetic features. Near‐infrared light‐induced membrane permeabilization triggers the “ultrafast” and “thorough” release of sunitinib (100% release in 5 min) for antiangiogenic therapy and also myeloid‐derived suppressor cell (MDSC) inhibition to reverse the immunosuppressive tumor environment. Subsequently, the small‐sized DOX‐NP liberated from the liposomes is more easily uptaken by tumor cells for improved immunogenic chemotherapy. RNA sequencing and immune‐related assay indicates therapeutic immune enhancement. This light‐triggered sequential delivery strategy demonstrates the potency in cancer multimodal therapy against multiple targets in different spatial positions in tumor microenvironment.
The biomimetic DS@HLipo targets the tumor site, where near‐infrared light‐induced membrane permeation triggers the “ultrafast” and “thorough” release of sunitinib for both antiangiogenic therapy and anti‐MDSC immunotherapy. The liberated doxorubicin (DOX)‐loaded small‐sized polymeric nanoparticles (DOX‐NP) from the liposomes can then be more easily ingested by tumor cells for improved immunogenic chemotherapy.
Living cell‐based drug delivery systems (LC‐DDSs) are limited by adverse interactions between drugs and carrier cells, typically drug‐induced toxicity to carrier cells and restriction of carrier ...cells on drug release. Here, a method is established to adsorb nanocarriers externally to living cells, thereby reducing cytotoxicity caused by drug uptake and realizing improved drug release at the disease site. It is found that a divalent metal ion‐phenolic network (MPN) affords adhesion of poly (lactic‐co‐glycolic acid) nanoparticles onto macrophage (Mφ) surfaces with minimized intracellular uptake and no negative effect on cell proliferation. On this basis, an Mφ‐DDS with doxorubicin‐loaded nanoparticles on cell surface (DOX‐NP@Mφ) is constructed. Compared to intracellular loading via endocytosis, this method well‐maintains bioactivity (viability and migration chemotaxis) of the carrier cell. By virtue of the photothermal effect of MPN at the tumor site, DOX‐NP‐associated vesicles are liberated for improved chemotherapy. This facile, benign, and efficient method (ice bath, 2 min) for extracellular nanoparticle attachment and minimizing intracellular uptake provides a platform technology for LC‐DDS development.
Macrophages with doxorubicin‐loaded polymeric nanoparticles attached on cell surface (DOX‐NP@Mφ) through metal‐phenolic networks (MPNs) are constructed. DOX‐NP@Mφ can actively navigate to the tumor site, where photothermal effect from MPNs liberates DOX‐NP for improved tumor cell uptake and chemotherapy.
As a class of smart materials, mechanofluorochromic (MFC) luminogens have promising applications in mechanosensors, security papers, and optical storage primarily based on their alternation in ...emission behaviors in response to mechanical stimuli. It has been discovered that most molecules having aggregation-induced emission (AIE) exhibit mechanofluorochromism. As one of the essential AIE cores, cyanoethylene has been widely used to build MFC molecules. This review focuses on the latest advances in the mechanofluorochromism of cyanoethylene derivatives with AIE properties, which incorporates mechanistic studies on mechanofluorochromism and MFC luminogens based on cyanoethylene. We hope that this review will provide a clear outlook on these novel functional materials to a broad range of scientists within exclusive disciplinary areas and attract more researchers to devote themselves to this exciting research area.
This review provides a clear overview of the recent progress in the mechanofluorochromism of cyanoethylene derivatives with aggregation-induced emission.
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•Wedelolactone, a natural compound, shows outstanding effects of anti-inflammation and anti-oxidative stress.•The alleviation to doxorubicin(DOX)-driven podocyte injury may contribute ...to the attenuation of renal damage.•Wedelolactone can regulate the IκK/IκB/NF-κB signaling pathway to alleviate levels of oxidative stress and inflammation.
The acute kidney injury(AKI) caused by nephrotoxic drugs contributes to inflammation and oxidative injury in podocytes. Wedelolactone (WED), a natural compound, is found with activities as anti-inflammation, anti-oxidative, anti-free radical,and etc. In this present study, MPC-5 cells were exposed to the nephrotoxic drugs doxorubicin (DOX). The results showed that WED significantly increased the SOD activity, CAT and GSH-Px levels, while significantly decreased the MDA content and ROS levels in DOX-induced MPC-5 cells. WED could also significantly decrease the levels of cytokines IL-6, MCP-1, TNF-α, and TGF-β1. Additionally, the activation and phosphorylation of IκKα, IκBα and NF-κB p65 was inhibited by WED. The co-treatment of PDTC (NF-κB inhibitor) and WED significantly reduced NF-κB p65 phosphorylation. These findings suggested that WED alleviated inflammation and oxidative stress of doxorubicin-induced MPC-5 cells through IκK/IκB/NF-κB signaling pathway.
Dispersed H3K27 trimethylation (H3K27me3) of the AGAMOUS (AG) genomic locus is mediated by CURLY LEAF (CLF), a component of the Polycomb Repressive Complex (PRC) 2. Previous reports have shown that ...the AG second intron, which confers AG tissue-specific expression, harbors sequences targeted by several positive and negative regulators.
Using RACE reverse transcription polymerase chain reaction, we found that the AG intron 2 encodes several noncoding RNAs. RNAi experiment showed that incRNA4 is needed for CLF repressive activity. AG-incRNA4 RNAi lines showed increased leaf AG mRNA levels associated with a decrease of H3K27me3 levels; these plants displayed AG overexpression phenotypes.
Genetic and biochemical analyses demonstrated that the AG-incRNA4 can associate with CLF to repress AG expression in leaf tissues through H3K27me3-mediated repression and to autoregulate its own expression level.
The mechanism of AG-incRNA4-mediated repression may be relevant to investigations on tissue-specific expression of Arabidopsis MADS-box genes.
Phase stability and elasticity of ammonia hydrate have been studied using Raman spectroscopy and Brillion scattering in diamond-anvil cells up to 53 GPa at 300 K. Here we have established the ...high-pressure phase diagram of ammonia hydrate in three different compositions, including ammonia monohydrate (AMH, NH3·H2O), dihydrate (ADH, NH3·2H2O), and trihydrate (ATH, NH3·3H2O). In contrast to previous experimental results, our Raman and Brillouin measurements at 300 K have shown that all three ammonia hydrates start to dehydrate at 2.1-2.2 GPa. Dehydration of the ammonia hydrate leads to the formation of single-crystal ice-VII and an increase in the concentration of NH3 in the residual liquid. The residual liquid finally turns into solid ammonia hemihydrate phase II (AHH-II) at 4-4.6 GPa, leading to a 28% jump in the compressional-wave velocity (VP). Considering a 10-15 vol% NH3 in the mantle of ice giants, AHH should thus be the dominant form of NH3 coexisting with H2O-ice in the ice giants. Further Brillouin measurements provide crucial constraints on the VP of AHH and the single-crystal elasticity of ice-VII at high pressures and 300 K. VP of AHH increases smoothly with pressure. No anomalous change in VP of AHH was identified up to 39 GPa, although a solid to solid phase transition was noted to occur at ~18 GPa by Raman measurements. In addition, the elasticity of single-crystal ice-VII, which was the dehydration product of ammonia hydrate, has been determined up to 53 GPa at 300 K. The deviation of C12 from C44 observed at 11.4 and 14.6 GPa could be caused by the hydrogen bond symmetrizations or the ordering of dipole of single-crystal ice-VII. An abnormal softening in the elastic moduli C11, C12, and the adiabatic moduli KS together with stiffening in C44 was observed between 42 and 53 GPa, which should be caused by the transition from ice-VII to its pre-transitional state. Of particular interest is the dramatic increase in the anisotropy of ice-VII with increasing pressure. Combining the sound velocity of AHH and ice-VII, we have modeled the VP of ice giants with a volume ratio of 20% AHH and 80% ice-VII in the mantle. The obtained high-pressure phase diagram and elastic properties of ammonia hydrate could contribute to understanding the structure of the mantle in the ice giants and satellites.
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