Search

The mode-locking operation is realized based on γ-graphyne for the first time, the vector nature of which is further studied. Additionally, an Er-doped Q-switched fiber laser with γ-graphyne as an optical switch is also firstly demonstrated.

Passively mode-locked lasers have been widely investigated as one of the effective methods to obtain ultrashort pulses. As an important part of passively mode-locked fiber lasers, the exploration of 2D material-based saturable absorber has become one of the hotspots in ultrafast photonics in recent years. Germanene, a novel 2D Dirac material, with ultrafast optical response and broadband optical absorption, is a promising alternative material for saturable absorber in mode-locked fiber lasers. In this paper, germanium nanosheets are prepared via liquid-phase exfoliated method, with the saturable absorption property systematically characterized in three major wavebands of the near-infrared region. The generation of ultrashort pulses based on germanene saturable absorber in fiber lasers is further realized, in a broad waveband (1000 nm) centered at 1061.1, 1559.3 and 1883.5 nm, respectively. In addition, noise-like pulses operation with central wavelength of 1558.6 nm is also obtained, and the formation of rogue waves is further demonstrated via statistical analysis. To the best of our knowledge, this is the first experimental verification of the broadband saturable absorption property of germanene-based devices, covering three major fiber laser wavelengths from 1.0 to 2.0 μm.

All-fiber mode converters for generating orbital angular momentum (OAM) beams have many applications in optical communications, optical sensing and lasers. Currently, it is a great challenge to use a long-period fiber grating (LPFG) to broadband excite high-order OAM modes above the second-order. Here, we demonstrate a preset-twist LPFG fabrication method, which introduces asymmetry in the refractive index modulation area, for efficient generation of third-order modes. Through optimization, the generation of third-order OAM modes with 99.55% conversion efficiency, 0.81 dB insertion loss, and over 99% purity is achieved with only 40 pitch number. In addition, a multi-period preset-twist LPFG is proposed and demonstrated to achieve the excitation of broadband third-order mode with conversion efficiency of more than 99%, insertion loss of less than 1 dB, and mode purity of more than 90%. The 15 dB bandwidth (96.8% conversion efficiency) of the LPFG is 109 nm in the wavelength range from 1475 nm to 1584 nm, and the 20 dB bandwidth (99% conversion efficiency) of the LPFG is 92 nm from 1488 nm to 1580 nm. To the best of our knowledge, this is the first time to generate efficient and broadband third-order mode using a long-period fiber grating.

A novel optical soliton dynamics phenomenon, called “invisible” pulsation, has gradually attracted extensive interest in recent years, which can only be identified effectively with the help of real-time spectroscopy technique, i.e., dispersive Fourier transformation (DFT). In this paper, based on a new bidirectional passively mode-locked fiber laser (MLFL), the “invisible” pulsation dynamics of soliton molecules (SMs) is systematically studied. It is indicated that the spectral center intensity, pulse peak power and relative phase of SMs are periodically changed during the “invisible” pulsation, while the temporal separation inside the SMs is constant. The degree of spectral distortion is positively correlated with the pulse peak power, which verifies that self-phase modulation (SPM) is the inducement of spectral distortion. Finally, the universality of the SMs “invisible” pulsation is further experimentally verified. We believe our work is not only conducive to the development of compact and reliable bidirectional ultrafast light sources, but also of great significance to enrich the study of nonlinear dynamics.

Trapped in the stringent adiabatic transmission condition of high-order modes, low-loss fused biconical taper mode selective coupler (FBT-MSC) has long been challenging to achieve. We identify the adiabatic predicament of high-order modes to stem from the rapid variation of the eigenmode field diameter, which is caused by the large core-cladding diameter difference of few-mode fiber (FMF). We demonstrate that introducing a positive-index inner cladding in FMF is an effective approach to address this predicament. The optimized FMF can be used as dedicated fiber for FBT-MSC fabrication, and exhibits good compatibility with the original fibers, which is critical for the wide adoption of MSC. As an example, we add inner cladding in a step-index FMF to achieve excellent adiabatic high-order mode characteristics. The optimized fiber is used to manufacture ultra-low-loss 5-LP MSC. The insertion losses of the fabricated LP01, LP11, LP21, LP02 and LP12 MSCs are 0.13 dB at 1541 nm, 0.02 dB at 1553 nm, 0.08 dB at 1538 nm, 0.20 dB at 1523 nm, and 0.15 dB at 1539 nm, respectively, with smoothly varying insertion loss across the wavelength domain. Additional loss is less than 0.20 dB from 1465.00 nm to 1639.31 nm, and the 90% conversion bandwidth exceeds 68.03 nm, 166.68 nm, 174.31 nm, 132.83 nm, and 84.17 nm, respectively. MSCs are manufactured using commercial equipment and a standardized process that takes just 15 minutes, making them a potential candidate for low-cost batch manufacturing in a space division multiplexing system.

We propose and design a 19-ring-air-core fiber that can support about 3000 orbital angular momentum (OAM) modes (156 modes in each ring) with 2.67 × 10−4 and mode groups by > 1.90 × 10−2, which can guarantee the stable transmission of OAM modes. This designed fiber is a potential candidate for applications in spatial division multiplexing (SDM) of optical channels to improve the capacity of next-generation high-speed optical communication systems, especially in short-distance applications. In this Letter, we also show the relationship between supported OAM mode numbers, total cross talk, and effective refractive index of intra-ring modes during the optimization of fiber through numerical simulations. It can provide a related reference for the future design of multi-ring-core fibers.

The purpose of this study is to explore the antitumor properties of resibufogenin (RB) in non-small cell lung cancer (NSCLC) and elucidate its underlying mechanism. A549 and H520 cells were treated with various concentrations of RB with or without NLRP3 inhibitor (MCC950), caspase-1 inhibitor (VX765), or N-acetyl-l-cysteine (an ROS scavenger). Cell counting kit-8 and colony formation assays were conducted to determine cell viability. Cell invasion was detected by using the transwell assay. The release of lactate dehydrogenase (LDH) was determined by the LDH detection assay. The protein expression levels of related genes were measured by western blotting and immunohistochemistry. The reactive oxygen species (ROS) level was detected by using a 2,7-dichlorodihydrofluorescein diacetate ROS Assay Kit. The in vivo effects of RB were evaluated in a xenograft mouse model. RB treatment reduced cell viability and invasion in a dose-dependent manner. Furthermore, RB also enhanced pyroptosis levels in A549 and H520 cells, as indicated by the increased release of LDH and pyroptosis-related proteins. Interestingly, we also found that the antiproliferative and antimetastatic effects of RB were alleviated by the blockade of pyroptosis using NLRP3 inhibitor MCC950. Further study demonstrated that RB induced pyroptosis in a caspase-1-dependent manner, as evidenced by the finding that VX765 effectively reversed the effects of RB on A549 and H520 cells. We also found that RB could trigger caspase-1-dependent pyroptosis through ROS-mediated NF-κB suppression. In summary, our findings provide a potential antitumor agent and a novel insight into the mechanism of RB treatment of NSCLC.

Background Esophageal squamous cell carcinoma (ESCC) is one of the prevalent and deadly cancers worldwide. Previous studies confirmed that endothelin-1 (ET-1) serves as an oncogene and therapeutic target in various tumors. However, the role and mechanism of ET-1 in the progression of ESCC remains largely unclear. Methods Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA level of ET-1 in ESCC tissues and cell lines. Cell counting kit-8 (CCK-8), flow cytometry and Transwell assay were performed to examine the proliferation, cell cycle arrest, invasion and migration capacity of ESCC cells. Western blot was applied to measure the expression of ET-1 and PI3K/Akt pathway-related proteins. Furthermore, we also assessed the effect of ET-1 on tumor growth in vivo. Results ET-1 was highly expressed in ESCC tissues and associated with poor outcomes. Knockdown of ET-1 significantly inhibited the proliferation, migration and invasion capacity of ESCC cells and promoted cell cycle arrest. Mechanistically, silencing of ET-1 exerts anti-proliferation and anti-metastasis activities via inactivation of the PI3K/Akt signaling pathway in ESCC in vitro and in vivo. Conclusions These findings uncover the effective suppression of cell proliferation and metastasis through silencing of ET-1 and blocking the PI3K/Akt signaling pathway, which is an attractive therapeutic regimen for the treatment of ESCC.

CNN is used to identify the number of openings, wedge angle and direction of multi-opening object with probing Gaussian beam. 97.37% accuracy is achieved for different classifications with 1° precision and up to 36 openings.

We design a dual concentric ring-core fiber with four ZDWs to enable a broadband OAM supercontinuum generation. A 3534-nm supercontinuum forms from 442 to 3976 nm at -40 dB, which covers beyond three-octave bandwidth.

An on-chip supercontinuum (SC) source spanning from 900 nm to 2000 nm has been experimentally presented and analyzed based on a

A well designed ring-core fiber can theoretically support numerous orbital angular momentum (OAM) modes with low crosstalk for space-division-multiplexing (SDM) data transmission, which is considered as a promising solution for overcoming the capacity crunch in optical communication network. However, the accumulated chromatic dispersion in OAM-fiber could limit the data speed and transmission distance of communication systems. A potential solution is to insert a dispersion compensation ring-core fiber with opposite-sign of dispersion in the transmission fiber along the fiber link. In this work, we propose a triple ring-core fiber with broadband negative dispersion. A highest negative dispersion of -24.47 ps/(nm·km) at 1550 nm and an average dispersion slope in the C band from -0.182 ps/(nm2·km) to 0.065 ps/(nm2·km) can be achieved to compensate multi-order dispersion. The effects of Ge-doping concentration fluctuation in the high-index ring core and fabrication errors on fiber geometric structures are also investigated. Furthermore, the effective mode area decreases as the widths of high-index rings increase due to the enhanced confinement ability. The designed triple ring-core fiber could offer potential for compensating OAM fiber links with positive dispersions.

High order modes in a six-mode fiber are separately observed and characterized using an Optical Frequency Domain Reflectometry (OFDR) method. Due to the difference in group refractive index between fundamental mode and the high order modes, Fresnel reflection peaks for each mode can be separated in beat frequency domain with their corresponding time delay. In the experiment, the fundamental mode and high order modes are excited in turn and observed at a 6.6 m six-mode fiber end, which agree with their beat frequency difference in theoretical simulation. The demonstration provides a flexible and feasible method for mode identification and characterization of all kinds of fibers.

We propose a low-loss broadband symmetric mode multiplexing coupler. By studying the influence of polarization on the coupler, multiplexing of LP11 and LP21 modes in the range of 990-1570 nm is realized.

Coherence supercontinuum of light-carrying OAM is generated over 1.2-octave spectral range from 852 nm to 2059 nm, by launching a 30-fs 60-kW hyperbolic secant pulse in a 3-cm Ge-doped ring-core silica fiber with all-normal dispersion.

The purpose of this study is to explore the antitumor properties of resibufogenin (RB) in non-small cell lung cancer (NSCLC) and elucidate its underlying mechanism. A549 and H520 cells were treated with various concentrations of RB with or without NLRP3 inhibitor (MCC950), caspase-1 inhibitor (VX765), or N-acetyl-l-cysteine (an ROS scavenger). Cell counting kit-8 and colony formation assays were conducted to determine cell viability. Cell invasion was detected by using the transwell assay. The release of lactate dehydrogenase (LDH) was determined by the LDH detection assay. The protein expression levels of related genes were measured by western blotting and immunohistochemistry. The reactive oxygen species (ROS) level was detected by using a 2,7-dichlorodihydrofluorescein diacetate ROS Assay Kit. The in vivo effects of RB were evaluated in a xenograft mouse model. RB treatment reduced cell viability and invasion in a dose-dependent manner. Furthermore, RB also enhanced pyroptosis levels in A549 and H520 cells, as indicated by the increased release of LDH and pyroptosis-related proteins. Interestingly, we also found that the antiproliferative and antimetastatic effects of RB were alleviated by the blockade of pyroptosis using NLRP3 inhibitor MCC950. Further study demonstrated that RB induced pyroptosis in a caspase-1-dependent manner, as evidenced by the finding that VX765 effectively reversed the effects of RB on A549 and H520 cells. We also found that RB could trigger caspase-1-dependent pyroptosis through ROS-mediated NF-κB suppression. In summary, our findings provide a potential antitumor agent and a novel insight into the mechanism of RB treatment of NSCLC.

This paper presents the vibration test method of the elastic modulus of glulam beams. Under the condition of simply supported, the elastic modulus of glulam beams is tested based on the vibration method. Compared with the static modulus tested by static load test and the natural frequency tested by finite element method, vibration-based detection method is proved to be feasible and accurate in measuring the elastic modulus of glued laminated beams.

Keratin is widely used in the biomaterial application, but the keratin prepared by the physical or chemical approach has relatively low molecular weight and mechanical properties. Here we report the preparation of high molecular keratin (HMK) with molecular weight of 120 kDa via multi-enzyme cascade pathway and its application in wound healing. Briefly, we prepared the soluble keratin from wool by keratinase and improved the molecular weight of keratin by transglutaminase (TGase). The HMK was coelectrospun with poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) and the prepared nanofibrous mats demonstrated improved mechanical properties. Ag nanoparticles (AgNPs) were synthesized on the nanofibers via in situ bioreduction, using the above-mentioned keratinase as the reducing agent. It is demonstrated that the PHBV/HMK/AgNPs nanofibrous mats possess favorable antibacterial properties and good biocompatibility. Moreover, in vivo wound healing assessment, the PHBV/HMK/AgNPs membrane displayed better wound healing ability than the control group. These results indicate that PHBV/HMK/AgNPs mats exhibit significant potential in tissue engineering.

Background/Aims: The aim of this study was to assess the prevalence and related factors of different types of urinary incontinence (UI) among Hebei women in China. Methods: A total of 2,500 women aged 20 years or more were sampled and interviewed face-to-face by well-trained interviewers. Results: Among these women, 35.2% (862/2,448) had UI. The prevalence of stress, urge, and mixed UI was 26.4% (647/2,448), 1.9% (47/2,448), and 6.9% (168/2,448), respectively. In multivariable logistic regression, age, constipation, pelvic organ prolapse, number of abortions, and cesarean sections were associated with both stress and mixed UI; body mass index, dysmenorrhea, vaginitis and cervicitis, fetal weight, and dystocia were associated with stress UI only; age of menarche and dystocia were associated with urge UI only, and living in a city or countryside, a history of pelvic operation, urinary infection, diseases of the respiratory system, heart disease, and alcohol consumption with mixed UI. Conclusions: UI is a highly prevalent condition among women in Hebei Province, PR China. Stress, urge, and mixed UI not only have some related factors in common but also have some different ones. Economic condition and a lack of UI-related knowledge are factors keeping patients from seeing a doctor.

A stable room-temperature multi-wavelength Brillouin–Raman fiber laser with a ring cavity configuration was proposed and experimentally investigated. An obvious suppressant effect for unstable mode hopping of multi-wavelength lasing oscillations induced by deeply saturated effect was observed in the ring cavity configuration. Stable room-temperature multi-wavelength lasing oscillations with more than 30 lasing lines and wavelength spacing of 0.076 nm were obtained with only 250 mW Raman pump power and a section of high nonlinear fiber with a length of 1.5 km. The lasing output is so stable that the maximum power fluctuations for the foremost three Stokes lines over more than 20 min of observation were less than 0.30 dB. The lasing stability of the laser was also compared with a linear cavity configuration with the same gain components and pump conditions. While using the linear laser cavity configuration, obvious mode hopping was observed. The minimum value of the maximum power fluctuations at all lasing lines over more than 10 min of observation was more than 0.90 dB.

Paecilomyces hepiali, one of the most valuable and effective Chinese medicinal herbs, possesses potential antioxidant, immunomodulatory, antitumor and anti‑inflammatory properties. The present study aimed to investigate the antifatigue and antihypoxic effects of Paecilomyces hepiali extract (PHC) in a mouse model. Using a rotating rod, forced swimming and running assessment, the antifatigue activity of PHC was determined. PHC administration for 7 days had no effect on mouse horizontal or vertical movement, indicating no neurotoxicity at the selected doses was observed. Using a normobaric hypoxia, sodium nitrite toxicosis and acute cerebral ischemia assessments, PHC was confirmed to possess antihypoxic effects. PHC treatment for 7 days significantly enhanced the serum and liver levels of adenosine triphosphate, superoxide dismutase and glutathione peroxidase, prior to and following 60 min of swimming. The levels of antioxidant‑associated proteins in the livers of the mice were analyzed using western blotting. PHC effectively increased the expression levels of phosphorylated (p)‑5'‑monophosphate (AMP)‑activated protein kinase (AMPK), p‑protein kinase B (AKT) and p‑mammalian target of rapamycin (mTOR). The results of the present study demonstrated that PHC efficiently enhanced endurance from fatigue and had antihypoxic effects through elevation of the antioxidant capacity in the serum and liver, at least in part through the AMPK and AKT/mTOR pathways. These results indicate the potential of this natural product as an antioxidant in the treatment of fatigue, hypoxia and their associated diseases.

An 800 nm band fiber Bragg grating sensing interrogation system using tilted FBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830 nm, with accuracy of 20 pm and scan speed 100Hz. Using FBG sensor, we achieve the temperature sensitivity of 1.8 °C and strain sensitivity of 18 μ ɛ.

The temperature and stress characteristics of double-clad fiber Bragg grating are investigated, respectively. The thermal decay characteristics according to the different anneal thermal, 100°C, 150°C, 200°C and 250°C are got. These results are very significant to estimate the properties of grating, such as thermal, wavelength and anneal time. Birefringence effect of the grating is also detected in rectangular inner cladding DCF gratings. By applying stress on the grating, strain is induced. One reflection peak of double-clad fiber Bragg grating becomes two peaks. The relation between the stress and the peak shift is obtained. The two reflection peaks can be tuned from 0 to 0.8nm. These results are more significant for estimate the sensor properties of the DCF Bragg gratings.

The photosensitivity and thermal decay of DCF Bragg grating written in Yb 3+ -doped and Er 3+ /Yb 3+ -co-doped DCF are experimentally investigated, respectively. Variation of amplitude of reflective-index modulation and effective reflective index with the UV exposure time are observed. Depend on the photosensitivity relations of hydrogen-loaded rare-earth-doped DCF, we fabricate diversiform reflectivity of DCF Bragg gratings with phase mask method, and the best reflectivity of the grating is 99.9%. The thermal decay characteristics according to the different anneal thermal, 100°C, 150°C, 200°C and 250°C are got. These results are very significant to estimate the properties of grating, such as thermal, wavelength and anneal time.