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【Objective】With the continuous emergence of information-based bandwidth-consuming services such as 5th Generation Mobile Communication Technology (5G), the Internet of Things, and cloud computing, people’s demand for high-speed information transmission has increased dramatically. However, due to the inherent nonlinear effects, the transmission capacity of single-mode optical fiber has approached the Shannon limit, and it will no longer be able to meet people’s needs for ultra-high-speed and large-capacity transmission. Solving the transmission capacity problem has become a top priority. In order to solve the needs of large-capacity communication systems and long-distance high-speed transmission problems, we have built a two-mode single-channel C-band Few Mode Fiber (FMF) transmission system.【Methods】At the transmitting end, an arbitrary waveform generator is used to convert the digital signal into an electrical signal and drive the In-phase and Quadrature (IQ) modulator to modulate the optical carrier. The modulated signal is transmitted simultaneously using two multiplexing technologies: Mode Division Multiplexing (MDM) and Polarization Division Multiplexing (PDM). In order to achieve long-distance transmission of dual-mode signals of 1 000 km, we construct a dual-circulation loop system. Each time the signal passes through the loop, it will pass through a 50 km FMF. After being transmitted to the target distance, the coupler outputs the signal to the demultiplexing module, and the coherent optical receiver performs homodyne detection on the demultiplexed modulated signal. Finally, the transmitted signal is stored in an oscilloscope for offline Digital Signal Processing (DSP). The signal is sequentially subjected to frequency domain dispersion compensation, downsampling, clock recovery, and least mean square algorithm to restore the original signal.【Results】It was found that within the range of Optical Signal-to-Noise Ratio (OSNR) of each channel in the experiment, the Bit Error Rate (BER) under low Signal to Noise Ratio (SNR) is close to the theoretical channel result. Under high SNR condition, the BER is 1×10-2, which is 2.5 dB away from the theoretical value. We test the BER of LP11a and LP11b modes at Back-To-Back (BTB) and 250, 500, 750 and 1 000 km transmission cases respectively. The BER at all distances are lower than the Low-Density Parity-Check (LDPC) soft decision threshold with 28% redundancy (5.2×10-2 Soft Decision - Forward Error Correction (SD-FEC)). The BER after 1 000 km transmission in the two modes are 1.7×10-2 and 1.8×10-2 respectively, and the total net transmission rate is 400 Gbit/s.【Conclusion】This article demonstrates the transmission of a 32 Gbaud MDM-PDM-16 Quadrature Amplitude Modulation (QAM) C-band signal in a 1 000 km two-mode single-channel FMF system. At the receiving end, the advanced Multiple Input Multiple Output (MIMO)-DSP algorithm is used for channel equalization, and the obtained two-mode BER of 1.7×10-2 and 1.8×10-2 are both lower than the LDPC SD-FEC threshold with 28% redundancy. The result reachs a domestic record of 400 Gbit/s net transmission rate based on FMF transmission, and highlight the potential of FMF in large-capacity long-distance transmission.

Creep characterization of different diameter silica bar core during directional solidification of the single crystal superalloy was investigated by suspension method. The scanning electron microscope (SEM) was employed to observe the microstructure of the surface and transversal section of crept silica bar. The energy dispersive spectroscopy (EDS) and X-ray diffraction technology were used to analyse and determine the composition of the reaction product. The experimental results show that the crept deformation amount increases with prolonging of creep time and decreasing of the diameter of the silica bar. When the creep time is 60 min, the diameter 0.5 mm silica bar has the largest creep deformation, and the average deformation is 30 mm, while the 2 mm silica bar is 24 mm. The interfacial reaction of SiO2 with C and Al, which are deposited on the silica bar surface due to the elevated temperature and low vacuum, induces the formation of porous layer. The volume fraction of the porous reaction products leads to the different crept deformation amount of different diameter silica bars. The creep deformation amount of silica bars has a linear relationship with the volume fraction of surface reaction products.

The aim of this study was to investigate the effects of grape seed extract (GSE), acerola cherry extract (ACE), and blueberry extract (BBE) on the physicochemical properties and structure of the yellow croaker surimi gel. In addition, molecular docking and molecular dynamics (MD) simulation were utilized to study the binding mechanism of yellow croaker's fibrillin and fruit extracts. Surimi gel with 1.5% GSE, ACE, and BBE had the highest water holding capacity, hardness, chewability, cohesion, breaking force, breaking distance, gel strength, and densest 3D network structure, according to the experiment's findings. Nevertheless, the cross‐linking of proteins in surimi was blocked with the further increase of fruit extract (1.5%–2.0%), and the existing network of surimi was weakened or even destroyed. Three fruit extracts had little effect on the secondary structure of the surimi gel. Besides, hydrophobic and disulfide bonds are the main chemical bonds of croaker surimi. Molecular docking showed that B‐type procyanidine (BP) interacted with ASN‐183, SER‐571, ASP‐525, ARG‐350, LYS‐188, GLU‐349, CYS‐353, and other active amino acids in croaker protein. Moreover, it can form strong hydrogen bond interaction with ASN‐183, SER‐571, ASP‐525, and ARG‐350 at the active sites of protein. The BP‐Larimichthys crocea protein system's MD simulation was carried out, and calculations for the simulation's root mean square deviation, root mean square fluctuation, radius of gyration, solvent accessible surface area, and hydrogen bonds were made. It was found that these indices can demonstrate that the BP binding contributes to the stability of the yellow croaker structure. [ABSTRACT FROM AUTHOR]

Purpose In the present work, we intended to explore the function of enhancer of zeste homolog 2 (EZH2) in modulated anesthetic reagent bupivacaine-induced neuronal apoptosis in spinal cord dorsal root ganglia (DRG). Methods Murine DRG explant was treated with 5 mM bupivacaine in vitro to induce neuronal apoptosis, which was examined by a TUNEL assay. Protein and mRNA expressions of EZH2 in bupivacaine-treated DRG were examined by western blot and qRT-PCR assays. EZH2 was downregulated by siRNA in bupivacaine-treated DRG. Its functional role in protecting bupivacaine-induced neuronal apoptosis was examined. In addition, apoptotic protein caspase-9 and EZH2-associated signaling pathway, and tropomyosin receptor kinase C (TrkC) were further investigated, by western blot assay, in EZH2-downregulated and bupivacaine-injured DRG. Results In vitro treatment of bupivacaine-induced DRG neuronal apoptosis, and upregulated EZH2 at both protein and mRNA levels. SiRNA transfection successfully downregulated EZH2, as confirmed by western blot and qRT-PCR assays. Examination of TUNEL assay showed that EZH2 downregulation rescued bupivacaine-induced DRG neuronal apoptosis. Moreover, in bupivacaine-injured DRG, EZH2 downregulation reduced caspase-9, whereas upregulated TrkC and phosphorylated-TrkC (p-TrkC). Conclusion EZH2 is upregulated, whereas inhibiting EZH2 exerted rescuing effect in anesthetics (bupivacaine)-induced spinal cord DRG. The possible downstream target of EZH2 inhibition may interact with caspase and TrkC signaling pathways., Author(s): Jinwei Zheng [sup.1] , Junping Chen [sup.1] , Guorong Wu [sup.1] , Chaoshuang Wu [sup.1] , Ruichun Wang [sup.1] , Wei Wang [sup.1] Author Affiliations: (Aff1) 0000 0004 1799 [...]

The influences of minor amounts of scandium on the microstructure and mechanical properties of as-cast ZA27 alloy have been experimentally investigated. The experimental results show that as far as the Sc addition is individually concerned, the refinement result of the as-cast ZA27 alloy with 0.5wt.%Sc addition is comparatively better. After alloying with minor amounts of Sc, the coarse dendrites of the ZA27 alloy are refined and transformed into the uniform and small equiaxed grain microstructure; also the eutectics among the grain boundaries become finer. The test results of mechanical properties show that the tensile strength and hardness of the as-cast ZA27 alloy containing 0.5wt.%Sc approach 495 MPa and 120.2 HB, increase by 28.5% and 33.1%, respectively, compared with those of the ZA27 alloy with no addition of Sc element, while the elongation of the alloy is improved to 7.6% from 2.7%. The SEM, EDAX and XRD analyses show that in the ZA27 alloy, the trace element Sc combines with Al to form the square Al3Sc phase particles, which serve as heterogeneous nuclei, facilitating the refinement of the microstructure and the improvement of the mechanical properties of the alloy.