Rolling bearing fault diagnosis based on RQA with STD and WOA-SVM.

A rolling bearing fault diagnosis method based on Recursive Quantitative Analysis (RQA) combined with time domain feature extraction and Whale Optimization Algorithm Support Vector Machine (WOA-SVM) is proposed. Firstly, the recurrence graph of the vibration signal is drawn, and the nonlinear feature parameters in the recurrence graph combined with Standard Deviation (STD) are extracted by recursive quantitative analysis method to generate feature vectors; after that, in order to construct the optimal support vector machine model, the Whale Optimization Algorithm is used to optimize the c and g parameters. Finally, both Recursive Quantitative Analysis and standard deviation are combined with the WOA-SVM model to perform fault diagnosis of rolling bearings. The rolling bearing datasets from Case Western Reserve University and Jiangnan University were used for example analysis, and the fault identification accuracy reached 100% and 95.00%, respectively. Compared to other methods, the method proposed in this paper has higher diagnostic accuracy and wide practical applicability, and the risk of accidents can be reduced through accurate fault diagnosis, which is also important for safety and environmental policies. This research originated in the field of mechanical fault diagnosis to solve the problem of fault diagnosis of rolling bearings in industrial production, it builds on previous research and explores new methods and techniques to fill some gaps in the field of mechanical fault diagnosis.

Directional Bloch surface wave coupling enabled by magnetic spin-momentum locking of light.

We study the magnetic spin-locking of optical surface waves. Through an angular spectrum approach and numerical simulations, we predict that a spinning magnetic dipole develops a directional coupling of light to transverse electric (TE) polarized Bloch surface waves (BSWs). A high-index nanoparticle as a magnetic dipole and nano-coupler is placed on top of a one-dimensional photonic crystal to couple light into BSWs. Upon circularly polarized illumination, it mimics the spinning magnetic dipole. We find that the helicity of the light impinging on the nano-coupler controls the directionality of emerging BSWs. Furthermore, identical silicon strip waveguides are configured on the two sides of the nano-coupler to confine and guide the BSWs. We achieve a directional nano-routing of BSWs with circularly polarized illumination. Such a directional coupling phenomenon is proved to be solely mediated by the optical magnetic field. This offers opportunities for directional switching and polarization sorting by controlling optical flows in ultra-compact architectures and enables the investigation of the magnetic polarization properties of light.

Electro-optic high-speed optical beam shifting based on a lithium niobate tapered waveguide.

We propose an electro-optic on-chip beam shifting device based on gradient microstructured electrodes and an optical tapered waveguide fabricated using lithium niobate (LN). The distribution of refractive index variations of the optical waveguide can be electro-optically defined and tailored by the designed gradient microstructured electrodes, which directs the beam propagation and shifting. The length of the beam shifting device is 18 mm and the width of the waveguide is gradually increased from 8 µm to 80 µm. The functionality of the beam shifting device is experimentally demonstrated, and it is observed that it has an electro-optic tunability of 0.41 µm/V, and a high-speed response time of 19 ns (λ=1310 nm). This study can provide potential applications in optical switching and modulation, beam scanning and ranging, optical spatial communications, etc.

Novel vandetanib derivative inhibited proliferation and promoted apoptosis of cancer cells under normoxia and hypoxia.

Over-expressions of epidermal growth factor receptor and vascular endothelial growth factor receptor were frequently associated with the metastasis of solid tumors. Vandetanib, a dual tyrosine kinase inhibitor of epidermal growth factor receptor and vascular endothelial growth factor receptor, was broadly effective in treating a variety of human solid tumors. The compelling evidence that hypoxia is involved in tumor resistance to cancer therapy. Hypoxia-inducible factor (HIF-1α), a major transcription factor in response to hypoxia, has been considered as a promising specific target for cancer therapy. We reported a stronger vandetanib derivative, compound 39, which was more potently decreased viability of A549, HT-29, MCF-7, HepG2, and HeLa cells than its parent compound vandetanib. Remarkable hypoxia-selectivity was observed in A549 cells (IC50 = 1.55 ± 0.23 µM under normoxia and 0.31 ± 0.06 µM under hypoxia, respectively) and HT-29 cells (IC50 = 12.89 ± 2.15 µM under normoxia and 3.47 ± 0.79 µM under hypoxia, respectively). The apoptosis of A549 and HT-29 cells induced by compound 39 were detected by flow cytometry. Western blot analysis demonstrated that compound 39 significantly down-regulated the anti-apoptotic B-cell lymphoma-2 (BCL-2) protein and up-regulated the expression of pro-apoptotic BCL2-Associated X (Bax) protein as well as promoted the cleavage of poly (ADP-ribose) polymerase PARP. HIF-1α was down-regulated by compound 39 in A549 and HT-29 cells under hypoxia. We also found that the depletion of intracellular Reduced Glutathione (GSH) as well as production of Reactive Oxygen Species (ROS) were critical for compound 39-mediated cell death.

SnSe-Coated Microfiber Resonator for All-Optical Modulation.

In this study, a tin monoselenide (SnSe)-based all-optical modulator is firstly demonstrated with high tuning efficiency, broad bandwidth, and fast response time. The SnSe nanoplates are deposited in the microfiber knot resonator (MKR) on MgF2 substrate and change its transmission spectra by the external laser irradiation. The SnSe nanoplates and the microfiber are fabricated using the liquid-phase exfoliation method and the heat-flame taper-drawing method, respectively. Due to the strong absorption and enhanced light-matter interaction of the SnSe nanoplates, the largest transmitted power tunability is approximately 0.29 dB/mW with the response time of less than 2 ms. The broad tuning bandwidth is confirmed by four external pump lights ranging from ultraviolet to near-infrared. The proposed SnSe-coated microfiber resonator holds promising potential for wide application in the fields of all-optical tuning and fiber sensors.

Therapeutic efficacy of tacrolimus in vernal keratoconjunctivitis: a meta-analysis of randomised controlled trials.

BACKGROUND AND OBJECTIVE: Tacrolimus has been widely used in recent years for treating allergic conjunctivitis, but there is currently no available meta-analysis regarding its therapeutic efficacy. This study systematically evaluated the effectiveness of tacrolimus in the treatment of allergic conjunctivitis. METHODS: Data obtained from literature searches of the PubMed, Cochrane Library, Embase, CNKI, and Wanfang databases were retrieved by combining medical subject words and free words. Literature was selected on the basis of established inclusion and exclusion criteria, and the extracted data were evaluated for risk of bias using RevMan 5.3 for meta-analysis. RESULTS: A total of 177 articles were retrieved, of which 5 articles were eventually selected, all of which involved tacrolimus treatment for vernal keratoconjunctivitis. A total of 203 samples were analysed. Results of the meta-analysis showed that the tacrolimus treatment group had significantly lower ocular objective sign scores (SMD -1.39, 95% CI -2.50 to -0.27; p<0.05) and had a significantly lower subjective symptom evaluation score (SMD -0.92, 95% CI -1.59 to -0.24; p<0.05) than the control group. CONCLUSION: Current evidence shows that tacrolimus is effective in treating vernal keratoconjunctivitis.

Ultrasensitive temperature sensor and mode converter based on a modal interferometer in a two-mode fiber.

This paper presents an ultrasensitive temperature sensor and tunable mode converter based on an isopropanol-sealed modal interferometer in a two-mode fiber. The modal interferometer consists of a tapered two-mode fiber (TTMF) sandwiched between two single-mode fibers. The sensor provides high-sensitivity temperature sensing by taking advantages of TTMF, isopropanol and the Vernier-like effect. The TTMF provides a uniform modal interferometer with LP01 and LP11 modes as well as strong evanescent field on its surface. The temperature sensitivity of the sensor can be improved due to the high thermo-optic coefficient of isopropanol. The Vernier-like effect based on the overlap of two interference spectra is applied to magnify the sensing capabilities with a sensitivity magnification factor of 58.5. The temperature sensor is implemented by inserting the modal interferometer into an isopropanol-sealed capillary. The experimental and calculated results show the transmission spectrum exhibit blue shift with increasing ambient temperature. Experimental results show that the isopropanol-sealed modal interferometer provides a temperature sensitivity up to -140.5 nm/°C. The interference spectrum has multiple dips at which the input LP01 mode is converted to the LP11 mode. This modal interferometer acts as a tunable multi-channel mode converter. The mode converter that can be tuned by varying temperature and mode switch is realized.

GRB10 rs1800504 Polymorphism Is Associated With the Risk of Coronary Heart Disease in Patients With Type 2 Diabetes Mellitus.

Diabetic vascular complications are one of the main causes of death and disability. Previous studies have reported that genetic variation is associated with diabetic vascular complications. In this study, we aimed to investigate the association between GRB10 polymorphisms and susceptibility to type 2 diabetes mellitus (T2DM) vascular complications. Eight single nucleotide polymorphisms (SNPs) in the GRB10 gene were genotyped by MassARRAY system and 934 patients with type 2 diabetes mellitus (T2DM) were included for investigation. We found that GRB10 rs1800504 CC+CT genotypes were significantly associated with increased risk of coronary heart disease (CHD) compared with TT genotype (OR = 2.24; 95%CI: 1.36-3.70, p = 0.002). Consistently, levels of cholesterol (CHOL) (CC+CT vs. TT, 4.44 ± 1.25 vs. 4.10 ± 1.00 mmol/L; p = 0.009) and low density lipoprotein cholesterin (LDL-CH) (CC+CT vs. TT, 2.81 ± 1.07 vs. 2.53 ± 0.82 mmol/L; p = 0.01) in T2DM patients with TT genotype were significant lower than those of CC+CT genotypes. We further validated in MIHA cell that the total cholesterol (TC) level in GRB10-Mut was significantly reduced compared with GRB10-WT; p = 0.0005. Likewise, the reversed palmitic acid (PA) induced lipid droplet formation in GRB10-Mut was more effective than in GRB10-WT. These results suggest that rs1800504 of GRB10 variant may be associated with the blood lipids and then may also related to the risk of CHD in patients with T2DM.

Tribbles pseudokinase 3 (TRIB3) contributes to the progression of hepatocellular carcinoma by activating the mitogen-activated protein kinase pathway.

BACKGROUND: Tribble pseudokinase 3 (TRIB3) plays a key role in regulating the malignancy of many tumors. This study examined its function in cancer cells and explored the potential mechanisms of action. METHODS: The expression of TRIB3 was examined in hepatocellular carcinomas (HCCs) using The Cancer Genome Atlas (TCGA) database. A TRIB3 lentivirus with a flag label was constructed and transfected into Huh7 and Hep3B human hepatoma cell lines to generate cells that stably overexpress TRIB3. A small interfering RNA (siRNA) was designed to knockdown TRIB3 mRNA in HepG2 and Huh7. Cell viability and cell colony formation assays were conducted. Flow cytometry was performed to assess the cell cycle in cells overexpressing TRIB3. Western blotting were performed to examine the expression of (Mitogen-activated protein kinase, MAPKK) (MEK), phosphorylated-MEK (p-MEK), extracellular signal-regulated kinase (ERK), and p-MEK in cells with TRIB3 knockdown. The correlation between TRIB3 and SMARCD3 was assessed using co-immunoprecipitation assays and immunofluorescence. RESULTS: TRIB3 was significantly overexpressed in advanced grade HCC tissues and was closely correlated with poor prognosis. TRIB3 overexpression promoted the cell growth and cell cycle but had little effect on migration capabilities in Huh7 and Hep3B cells. Conversely, knockdown of TRIB3 had slow down the cell growth in Huh7 and HepG2 cells detected by CCK8 and colony formation assay. The expression of MEK and ERK at both the protein and mRNA levels were downregulated when TRIB3 was knocked down. The protein expression of p-ERK and p-MEK were also downregulated upon TRIB3 silencing. SMARCD3 is a transcript factor that is belongs to the SWI/SNF complex and has been shown to regulate many genes. Indeed, co-immunoprecipitation assays demonstrated that TRIB3 interacts with SMARCD3 in the nucleus, suggesting that it may regulate TRIB3 in HCCs. CONCLUSIONS: This study demonstrated that TRIB3 promotes the malignancy of HCC cells and its expression may be a potential diagnostic biomarker for HCC progression.

Broadband mode-selective couplers based on tapered side-polished fibers.

We propose the broadband mode-selective coupler (MSC) formed with a side-polished six mode fiber (6MF) and a tapered side-polished small core single-mode fiber (SC-SMF) or an SMF. The MSCs are designed to allow the LP01 mode in the SC-SMF and SMF to completely couple to the LP01, LP11, LP21, LP02, LP31, LP12 modes in the 6MF over a broadband wavelength range. The phase-matching conditions of the MSCs are satisfied by tapering the SC-SMF and SMF to specific diameters. The tapered fibers are side-polished to designed residual fiber thickness using the wheel polishing technique. The effective indices of the side-polished fibers are measured with the prism coupling method. The MSCs provide high coupling ratio and high mode purity. High coupling efficiencies in excess of 81% for all the higher-order modes are obtained in the wavelength range 1530-1600 nm. For the LP01, LP11, LP21, LP02, LP31, LP12 MSCs at 1550 nm, the coupling ratios are 96.2%, 99.8%, 89.5%, 85.0%, 90.9%, 96.1%, respectively, and the mode purity of the MSCs is higher than 88.0%. The loss of the MSCs is lower than 1.8 dB in the wavelength range 1530-1600 nm. This device can be applied in broadband mode-division multiplexing transmission systems.

Highly efficient second harmonic generation of thin film lithium niobate nanograting near bound states in the continuum.

Bound states in the continuum (BICs) are ubiquitous physical phenomena where such states occur due to strong coupling between leaky modes in side lossy systems. BICs in meta-optics and nanophotonics enable optical mode confinement to strengthen local field enhancement in nonlinear optics. In this study, we numerically investigate second-harmonic generation (SHG) in the vicinity of BICs with a photonic structure comprising one-dimensional nanogratings and a slab waveguide made of lithium niobate (LiNbO3, LN). By breaking the symmetry of LN nanogratings, BICs transition to quasi-BICs, which enable strong local field confinement inside LN slab waveguide to be supported, thereby resulting in improving SHG conversion with lower pump power of fundamental frequency (FW). With a peak intensity of 1.33 GW cm-2at the FW, our structure features a second-harmonic conversion efficiency up to 8.13 × 10-5at quasi-BICs. We believe that our results will facilitate the application of LN in integrated nonlinear nanophotonic.

A broadband and low-power light-control-light effect in a fiber-optic nano-optomechanical system.

The coupling of the optical and mechanical degrees of freedom using optical force in nano-devices offers a novel mechanism to implement all-optical signal processing. However, the ultra-weak optical force requires a high pump optical power to realize all-optical processing. For such devices, it is still challenging to lower the pump power and simultaneously broaden the bandwidth of the signal light under processing. In this work, a simple and cost-effective optomechanical scheme was demonstrated that was capable of achieving a broadband (208 nm) and micro-Watt (∼624.13 µW) light-control-light effect driven by a relatively weak optical force (∼3 pN). In the scheme, a tapered nanofiber (TNF) was evanescently coupled with a substrate, allowing the pump light guided in the TNF to generate a strong transverse optical force for the light-control-light effect. Additionally, thanks to the low stiffness (5.44 fN nm-1) of the TNF, the light-control-light scheme also provided a simple method to measure the static weak optical force with a minimum detectable optical force down to 380.8 fN. The results establish TNF as a cost-effective scheme to break the limitation of the modulation wavelength bandwidth (MWB) at a low pump power and show that the TNF-optic optomechanical system can be well described as a harmonic oscillator.

All-Optical Tuning of Light in WSe2-Coated Microfiber.

The tungsten diselenide (WSe2) has attracted considerable interest owing to their versatile applications, such as p-n junctions, transistors, fiber lasers, spintronics, and conversion of solar energy into electricity. We demonstrate all-optical tuning of light in WSe2-coated microfiber (MF) using WSe2's broad absorption bandwidth and thermo-optic effect. The transmitted optical power (TOP) can be tuned using external incidence pump lasers (405, 532, and 660 nm). The sensitivity under 405-nm pump light excitation is 0.30 dB/mW. A rise/fall time of ~ 15.3/16.9 ms is achieved under 532-nm pump light excitation. Theoretical simulations are performed to investigate the tuning mechanism of TOP. The advantages of this device are easy fabrication, all-optical control, high sensitivity, and fast response. The proposed all-optical tunable device has potential applications in all-optical circuitry, all-optical modulator, and multi-dimensionally tunable optical devices, etc.

Electron-plasmon interaction on lithium niobate with gold nanolayer and its field distribution dependent modulation.

Surface plasmon resonance (SPR) enables strong field confinement, opening thereby new avenues for device miniaturization and reducing energy consumption. Plasmonic devices with electrical tunability attract tremendous interest for various applications. Most of the current researches achieved SPR modulation with relatively large driving voltages, or by other relatively low-speed tuning approaches, such as thermo-optic, magneto-optic, acousto-optic etc. In this paper, we propose and demonstrate an efficiently electrical SPR modulation based on lithium niobate (LN) with gold nanolayer (~81 nm) via electron-plasmon interaction. Efficient intensity modulation and wavelength shift (in visible band) of ~5.7 dB/V and ~36.3 nm/V are respectively obtained with low DC current. More importantly, modulation phenomenon of field distribution dependent is also observed and experimentally unveiled. Further performance is analyzed in terms of AC modulation and polarization characteristics. This key achievement opens up opportunities for applications such as optical interconnection, electric field sensing, electrically plasmonic modulation, etc.

Broadband all-light-control with WS2 coated microfibers.

All-optical light amplitude tuning functionality is demonstrated in a layered tungsten disulfide (WS2) nanosheets coated microfiber (MF) structure. Due to the strong light-matter interactions between WS2 nanosheets and the evanescent field around the MF, a large variation in the transmitted power can be observed under both external and internal pump light excitations over a broadband spectrum (~100 nm). A power variation rate of ~0.3744 dB/mW is obtained under external violet pump light excitation, whereas the power variation rate of similar devices in the state of the art are usually less than 0.3 dB/mW. In terms of the response time, a moderate rise/fall time of ∼20.5/19.6 ms is achieved, which is mainly limited by the employed structure fabrication methods. These results indicate that the optical transmitted power of the WS2 coated MF can be modulated by different pump light with the power in the order of mW, thus the proposed device might have potential applications in all optical controllable devices and sensors, etc.

Side-polished few-mode fiber based surface plasmon resonance biosensor.

The fiber geometry, fiber parameters and mode-guiding properties are crucial for realizing high-performance fiber-based sensors. In this work, we propose and demonstrate a few-mode fiber (FMF)-based surface plasmon resonance (SPR) biosensor. The FMF-SPR sensor was fabricated via side-polishing a few-mode fiber and coating a thin layer of gold film, on the basis of the optimization of fiber geometry, thickness of the gold film and mode selection, which were performed with the finite element method. The refractive index (RI) sensing performance of three such sensors with different residual fiber thicknesses were investigated. In the RI range from 1.333 to 1.404, the highest sensitivity up to 4903 nm/RIU and a figure of merit of 46.1 RIU-1 are achieved. For testing the bovine serum albumin (BSA) solution, an averaged BSA RI sensitivity of 6328 nm/RIU and an averaged BSA concentration sensitivity of 1.17 nm/(mg/ml) are realized. Benefiting from only a few modes supported in the FMF, a smaller line-width of the SPR spectrum is obtained, which further results in a higher figure of merit (FOM). Moreover, when combined with the superiority of the mode-multiplexing technology brought by the FMF, the FMF-SPR sensors may find applications in biochemical analysis with high performance and high throughputs.

Fano Resonance on Nanostructured Lithium Niobate for Highly Efficient and Tunable Second Harmonic Generation.

Second harmonic generation (SHG) is an important nonlinear process which is critical for applications, such as optical integrated circuit, nonlinear microscopy, laser, etc. Many challenges remain in the improvement of nonlinear conversion efficiency, since the typical value is of only 10-5 in nanostructures. Here, we theoretically demonstrate a periodic structure consisting of a lithium niobate (LN) bar and an LN disk, on a nanoscale (~300 nm) thin-film platform, which is proposed for a highly efficient SHG. By breaking the structure symmetry, a Fano resonance with a high Q, up to 2350 and a strong optical field enhancement reaching forty-two folds is achieved, which yields a high conversion efficiency, up to 3.165 × 10-4. In addition to its strong second harmonic (SH) signal, we also demonstrate that by applying only 0.444 V on the planar electrode configurations of the nanostructured LN, the wavelength of SH can be tuned within a 1 nm range, while keeping its relatively high conversion efficiency. The proposed structure with the high nonlinear conversion efficiency can be potentially applied for a single-molecule fluorescence imaging, high-resolution nonlinear microscopy and active compact optical device.

Highly sensitive all-optical control of light in WS2 coated microfiber knot resonator.

All-optical light-control-light functionality is realized in a layered tungsten disulfide (WS2) nanosheet coated microfiber knot resonator (MKR) structure. Mainly due to the photon generated excitons induced refractive index variation in WS2 nanosheets, a large variation in the transmitted power (∆T) can be observed under external violet/red laser excitation. The ∆T variation rates can reach up to ~0.4 dB/mW under violet pump light excitation whereas the state of the art light-control-light structures usually has a variation rate of less than 0.25 dB/mW. In terms of the response time, the averaged rise/fall time is ~0.12/0.1 s. The demonstrated structure has the advantages of easy fabrication, low cost and high sensitivity, therefore, it might be a promising candidate for building future all-fiber-optics based functional devices and all-optical circuitry.

Electro-optic deflection in a lithium niobate quasi-single mode waveguide with microstructured electrodes.

We propose an electro-optic mode deflection device based on an annealed proton exchange (APE) waveguide in lithium niobate, associated with isosceles-triangle-shaped array electrodes and a horn-shaped input waveguide. The input waveguide is tapered down to ensure that the output of the device has a good beam quality, i.e., a quasi-single mode in this case. This new device allows beam deflection at a relative low voltage and large deflection angle. At an APE-waveguide width of 80 µm, mode deflections of 0.265 and 0.240 µm/V are obtained for 1064 and 980 nm, respectively. This beam deflection device can be applied in high-speed optical switch, and beam smoothing of a high-power laser, etc.

High-sensitivity vector magnetic field sensor based on side-polished fiber plasmon and ferrofluid.

A high-sensitivity vector magnetic field is proposed and demonstrated. The sensor consists of a side-polished-fiber (SPF)-based surface plasmon resonance (SPR) structure integrated with ferrofluid. Because of the high refractive index sensitivity of the SPR scheme and the outstanding magneto optical properties of ferrofluid, the sensor shows a high sensitivity (up to 598.7 pm/Oe) to magnetic field intensity. Moreover, owing to the non-circular-symmetric geometry of the SPF and non-uniform distribution of the ferrofluid around the SPF, the sensor exhibits a sensitivity of -5.63 nm/deg to the orientation of the magnetic field. The proposed vector magnetic field sensor, integrating over magnetic, plasmonic, and fiber-optic schemes, is highly sensitive to both the intensity and orientation of the magnetic field simultaneously, and holds potential in applications in many fields, such as medicine, industry, and the military.