High fatigue resistance in a titanium alloy via near-void-free 3D printing.

The advantage of 3D printing-that is, additive manufacturing (AM) of structural materials-has been severely compromised by their disappointing fatigue properties1,2. Commonly, poor fatigue properties appear to result from the presence of microvoids induced by current printing process procedures3,4. Accordingly, the question that we pose is whether the elimination of such microvoids can provide a feasible solution for marked enhancement of the fatigue resistance of void-free AM (Net-AM) alloys. Here we successfully rebuild an approximate void-free AM microstructure in Ti-6Al-4V titanium alloy by development of a Net-AM processing technique through an understanding of the asynchronism of phase transformation and grain growth. We identify the fatigue resistance of such AM microstructures and show that they lead to a high fatigue limit of around 1 GPa, exceeding the fatigue resistance of all AM and forged titanium alloys as well as that of other metallic materials. We confirm the high fatigue resistance of Net-AM microstructures and the potential advantages of AM processing in the production of structural components with maximum fatigue strength, which is beneficial for further application of AM technologies in engineering fields.

Machine Learning on Microstructure-Property Relationship of Lithium-Ion Conducting Oxide Solid Electrolytes.

Understanding the structure-property relationship of lithium-ion conducting solid oxide electrolytes is essential to accelerate their development and commercialization. However, the structural complexity of nonideal materials increases the difficulty of study. Here, we develop an algorithmic framework to understand the effect of microstructure on the properties by linking the microscopic morphology images to their ionic conductivities. We adopt garnet and perovskite polycrystalline oxides as examples and quantify the microscopic morphologies via extracting determined physical parameters from the images. It directly visualizes the effect of physical parameters on their corresponding ionic conductivities. As a result, we can determine the microstructural features of a Li-ion conductor with high ionic conductivity, which can guide the synthesis of highly conductive solid electrolytes. Our work provides a novel approach to understanding the microstructure-property relationship for solid-state ionic materials, showing the potential to extend to other structural/functional ceramics with various physical properties in other fields.

Wheat TaSnRK2.10 phosphorylates TaERD15 and TaENO1 and confers drought tolerance when overexpressed in rice.

Wheat (Triticum aestivum) is particularly susceptible to water deficit at the jointing stage of its development. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) acts as a signaling hub in the response to drought stress, but whether SnRK2 helps plants cope with water deficit via other mechanisms is largely unknown. Here, we cloned and characterized TaSnRK2.10, which was induced by multiple abiotic stresses and phytohormones. Ectopic expression of TaSnRK2.10 in rice (Oryza sativa) conferred drought tolerance, manifested by multiple improved physiological indices, including increased water content, cell membrane stability, and survival rates, as well as decreased water loss and accumulation of H2O2 and malonaldehyde. TaSnRK2.10 interacted with and phosphorylated early responsive to dehydration 15 (TaERD15) and enolase 1 (TaENO1) in vivo and in vitro. TaERD15 phosphorylated by TaSnRK2.10 was prone to degradation by the 26S proteasome, thereby mitigating its negative effects on drought tolerance. Phosphorylation of TaENO1 by TaSnRK2.10 may account for the substantially increased levels of phosphoenolpyruvate (PEP), a key metabolite of primary and secondary metabolism, in TaSnRK2.10-overexpressing rice, thereby enhancing its viability under drought stress. Our results demonstrate that TaSnRK2.10 not only regulated stomatal aperture and the expression of drought-responsive genes, but also enhanced PEP supply and promoted the degradation of TaERD15, all of which enhanced drought tolerance.

Joint equalization of RSOP and PMD fused probability-aware with square-root cubature Kalman filter for the PDM PCS-64QAM system under extreme scenarios.

Extreme scenario of lightning strikes would generate ultra-fast rotation of state-of-polarization (RSOP) up to 5.1 Mrad/s and large polarization mode dispersion (PMD) in optical ground wire (OPGW). Unfortunately, the conventional multiple modulus algorithm (MMA) cannot equalize these polarization impairments in polarization division multiplexing (PDM) probabilistic constellation shaping (PCS)-64QAM system. Moreover, due to unavoidable linearization errors and higher modulation order, the extended Kalman filter based on measurement equations of concatenated multiplication (EKF-CM) is highly unstable and fails under such scenarios. To address the above issues, we have proposed a joint equalization scheme of PMD and RSOP, which fuses probability-aware with square-root cubature Kalman filter (PA-SCKF). Firstly, according to the characteristic that the amplitude of PCS signals obeys mixed Rician distribution, the scheme combines maximum a posteriori criterion to obtain the optimal radius of constellation ring which the received symbol belongs to, for the sake of calculating the innovations of SCKF. Secondly, it performs joint equalization of PMD and RSOP impairments based on SCKF and time-frequency conversion architecture. 28GBaud PDM PCS-64QAM simulation results demonstrate that our scheme can jointly equalize maximum impairments of 8.34 Mrad/s RSOP and 90ps DGD under entropy of 4.5bits/symbol. Additionally, only 0.9 dB OSNR penalty is obtained after joint equalization of 6 Mrad/s RSOP with 70ps DGD impairments. Even under entropy of 5.5bit/symbol, it can still jointly equalize impairments of 6.05 Mrad/s RSOP with 60ps DGD. Furthermore, 16GBaud PCS-64QAM experimental results indicate that the maximum joint equalization performances of PA-SCKF scheme under entropy of 4.5bit/symbol and 5bit/symbol are 17 Mrad/s RSOP with 52ps DGD, and 9 Mrad/s RSOP with 52ps DGD, respectively. These results manifest that our PA-SCKF scheme outperforms both MMA and EKF-CM schemes. Importantly, its complexity is on an order of O(Llog2 L), which is comparable to that of EKF-CM scheme.

Joint equalization of frequency offset and phase noise using two-stage cascaded extended Kalman filter for discrete spectrum 16/64APSK NFDM systems.

For the discrete spectrum nonlinear frequency division multiplexing (DS-NFDM) 16/64 amplitude phase shift keying (APSK) system, the inevitable laser impairments including frequency offset (FO) and carrier phase noise (CPN) would cause different rotations of the received signal constellations. In addition, the combined effect of FO and amplifier spontaneous emission (ASE) noise induces the eigenvalue shift, accordingly the residual channel impairment (RCI) is inevitably yielded. To address the above problems, we deduce the joint impairment model of FO, CPN and RCI, and then propose a joint equalization scheme using two-stage cascaded extended Kalman filter (TSC-EKF) for these impairments. It performs frequency offset compensation in the first stage, subsequently carries out joint equalization of CPN and RCI in the second stage. Meanwhile, the minimum Euclidean distance and phase difference between the received symbols and the ideal 16/64APSK constellations are ingeniously fused to calculate the innovations of TSC-EKF. The effectiveness has been verified by 2 GBaud DS-NFDM 16/64 APSK simulations and DS-NFDM 16APSK transmission experiments. The results demonstrate that when performing the joint equalization of FO, CPN and RCI, the maximum FOE range of TSC-EKF scheme achieves 1.2 and 9.6 times as that of nonlinear frequency domain (NFD) scheme and fast Fourier transform -Like (FFT-Like) scheme, respectively. Furthermore, its maximum LW tolerance reaches 3.3 times as that of the M-th power scheme. Importantly, the complexity of TSC-EKF is 63.4% as that of NFD scheme and on an order of O(N).

Lineage 1 PRRSVs infection induces hemorrhagic injury in intestines of piglets: Effects on complement and coagulation cascades.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a highly transmissible disease of significant concern in the pig industry. Previous studies have demonstrated that the XM-2020 strain (a lineage 1.8 PRRSV IA/2012/NADC30) can induce special hemorrhagic injury in the small intestines. However, the specific mechanism underlying this injurious effect remains incompletely understood. In this study, we examined the pathogenic properties of XM-2020 and YC-2020 strains (a lineage 1.5 PRRSV IA/2014/NADC34) in piglets. Animal pathogenic tests revealed that with either Lineage 1 PRRSVs strains XM-2020 or YC-2020 demonstrated pronounced intestinal hemorrhage and suppression of peripheral immunological organs, comparing to JXA1 infection. Transcriptome analysis of diseased small intestines unveiled that PRRSV infection stimulated oxidative and inflammatory reactions. Remarkably, we also observed activation of the complement system alongside a notable down-regulation of complement and coagulation cascade pathways in the Lineage 1 PRRSVs infection group. Based on these findings, we propose that the primary mechanism driving the hemorrhagic injury of the small intestine caused by Lineage 1 PRRSVs is the suppression of complement and coagulation cascades resulting from immunosuppression. This discovery deepens our understanding of the pathogenicity of PRRSV in the small intestine and provides promising ways out for the development of innovative strategies aimed at controlling PRRSV.

Quantitative evaluation of choroidal and retinal microvasculature post-alcohol consumption: A pilot study.

PURPOSE: The aim of this study was to assess the impact of acute, heavy alcohol consumption on the ocular microvasculature, providing insight into the largely unexplored response of microvascular structures to excessive drinking. METHODS: Healthy volunteers in this prospective pilot study were tasked with consuming spirits, wine, and water at different times. Alcohol intake was measured according to body weight (g/kg). The ocular microvascular parameters primarily including choroidal volume (CV) and choroidal vessel volume (CVV) reflecting arteriolovenularity, and choroidal capillary density (CCD) reflecting capillary, were evaluated using swept-source optical coherence tomography angiography at baseline and 0.5-, 1-, 2-, and 3-hour post-consumption. RESULTS: A total of 34 eyes underwent 170 successful examinations in this study. After consuming spirits or wine, we observed significant decreases in CV and CVV values (all P < 0.01 for 0.5-, 1-, 2-, and 3-hour post-consumption), along with significant increase in CCD (P < 0.05 at 0.5-, 1-, 2-hour post-spirits consumption and 1-hour post-wine consumption). The most pronounced changes occurred 1-hour after spirits or wine consumption (all P < 0.001 in both univariate and multivariate model). However, post-consumption changes in the ocular microvasculature showed no significant differences between spirits and wine (P > 0.05). Additionally, no significant differences were observed in any parameters after water intake (all P > 0.05). CONCLUSIONS: Excessive alcohol consumption leads to ocular arteriolovenular vasoconstriction and capillary vasodilation, most evident 1-hour post-consumption of spirits and wine. Our research provides insight into alcohol's immediate ocular microvascular effects, hinting at systemic microvascular effects.

Association between three-dimensional morphological features and functional indicators of neovascular age-related macular degeneration.

PURPOSE: To investigate the correlation between morphological lesions and functional indicators in eyes with neovascular age-related macular degeneration (nAMD). METHODS: This was a prospective observational study of treatment-naïve nAMD eyes. Various morphological lesions and impaired retinal structures were manually measured at baseline and month-3 in three-dimensional optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images, including the volumes (mm3) of macular neovascularization (MNV), avascular subretinal hyperreflective material (avascular SHRM), subretinal fluid (SRF), intraretinal fluid (IRF), serous pigment epithelial detachment (sPED) and the impaired area (mm2) of ellipsoid zone (EZ), external limiting membrane (ELM) and outer nuclear layer (ONL). RESULTS: Sixty-three eyes were included. The volume of avascular SHRM showed persistent positive associations with the area of EZ damage, both at baseline, month-3, and change values (all P < 0.001). Poor BCVA (month-3) was associated with larger volumes of baseline IRF (ß = 0.377, P < 0.001), avascular SHRM (ß = 0.306, P = 0.032), and ELM impairment area (ß = 0.301, P = 0.036) in multivariate model. EZ and ELM impairment were primarily associated with baseline avascular SHRM (ß = 0.374, p = 0.003; ß = 0.388, P < 0.001, respectively), while ONL impairment primarily associated with MNV (ß = 0.475, P < 0.001). CONCLUSION: The utilization of three-dimensional measurements elucidates the intrinsic connections among various lesions and functional outcomes. In particular, avascular SHRM plays an important role in prognosis of nAMD.

Epigenome-wide meta-analysis of prenatal maternal stressful life events and newborn DNA methylation.

Prenatal maternal stressful life events are associated with adverse neurodevelopmental outcomes in offspring. Biological mechanisms underlying these associations are largely unknown, but DNA methylation likely plays a role. This meta-analysis included twelve non-overlapping cohorts from ten independent longitudinal studies (N = 5,496) within the international Pregnancy and Childhood Epigenetics consortium to examine maternal stressful life events during pregnancy and DNA methylation in cord blood. Children whose mothers reported higher levels of cumulative maternal stressful life events during pregnancy exhibited differential methylation of cg26579032 in ALKBH3. Stressor-specific domains of conflict with family/friends, abuse (physical, sexual, and emotional), and death of a close friend/relative were also associated with differential methylation of CpGs in APTX, MyD88, and both UHRF1 and SDCCAG8, respectively; these genes are implicated in neurodegeneration, immune and cellular functions, regulation of global methylation levels, metabolism, and schizophrenia risk. Thus, differences in DNA methylation at these loci may provide novel insights into potential mechanisms of neurodevelopment in offspring.

Antifreeze Polysaccharides from Wheat Bran: The Structural Characterization and Antifreeze Mechanism.

Exploring a novel natural cryoprotectant and understanding its antifreeze mechanism allows the rational design of future sustainable antifreeze analogues. In this study, various antifreeze polysaccharides were isolated from wheat bran, and the antifreeze activity was comparatively studied in relation to the molecular structure. The antifreeze mechanism was further revealed based on the interactions of polysaccharides and water molecules through dynamic simulation analysis. The antifreeze polysaccharides showed distinct ice recrystallization inhibition activity, and structural analysis suggested that the polysaccharides were arabinoxylan, featuring a xylan backbone with a majority of Araf and minor fractions of Manp, Galp, and Glcp involved in the side chain. The antifreeze arabinoxylan, characterized by lower molecular weight, less branching, and more flexible conformation, could weaken the hydrogen bonding of the surrounding water molecules more evidently, thus retarding the transformation of water molecules into the ordered ice structure.

BF3·OEt2 Catalyzed Cascade [4 + 2] Benzannulation of Vinyloxiranes with Coumarins to Construct Benzocoumarin Derivatives.

A BF3·OEt2-catalyzed cascade cyclization reaction of vinyloxirane with coumarin is described, affording the benzocoumarin derivatives with moderate to excellent yields (72-92%). The reaction demonstrates exceptional substrate tolerance and has been extensively explored for its potential in drug development, including scale-up experiments, functional group transformations, and screening of the products for anticancer activity. Moreover, the reaction mechanism has been rigorously validated through intermediate trapping and control experiments. Additionally, this reaction represents the uncommon nonmetal catalyzed intermolecular cyclization of vinyloxiranes.

Natural course of age-related retentional avascular pigment epithelial detachment: Support for the lipid barrier hypothesis.

PURPOSE: Retentional pigment epithelial detachment (PED) associated with age-related scattered hypofluorescent spots on late-phase indocyanine green angiography (ASHS-LIA) is hypothesized to be caused by Bruch's membrane's lipid barrier. This study aimed to report the natural course of retentional PED and evaluate the relationship between retentional PED evolution and ASHS-LIA. METHODS: Patients with treatment-naïve retentional PED were enrolled and observed every 3 months for at least 12 months. Treatment was not performed except for secondary macular neovascularization. RESULTS: In 55 studied eyes with a median follow-up of 18.0 (range: 12-36) months, 87.3% (48/55) of the retentional PEDs persisted, 7.3% (4/55) resolved, and 5.5% (3/55) progressed to polypoidal choroidal vasculopathy. The mean PED area significantly increased during the follow-up (P <0.001) and with the ASHS-LIA grade at each follow-up point (all P <0.05), especially during the first 6 months before approaching the edge of confluent ASHS-LIA. Persistent PEDs were mostly stable (52.1%) or enlarged (45.8%) but reduced in only 1 case (2.1%) due to RPE microrip at the edge of PED. The persistent PEDs were all within the ASHS-LIA region, especially the macular confluence region. The resolved PEDs all had grade 1 ASHS-LIA and resolved after gradual expansion of PED beyond the confluent ASHS-LIA region. PEDs that progressed to MNV all had confluent grade 2 or 3 ASHS-LIA. RPE breaks or apertures within PED did not affect the progression of the PED. CONCLUSION: The natural course of retentional PED is closely related to the features of ASHS-LIA and supports its lipid-barrier hypothesis.

A Trojan-Horse-Like Biomimetic Nano-NK to Elicit an Immunostimulatory Tumor Microenvironment for Enhanced GBM Chemo-Immunotherapy.

Although the chemo- and immuno-therapies have obtained good responses for several solid tumors, including those with brain metastasis, their clinical efficacy in glioblastoma (GBM) is disappointing. The lack of safe and effective delivery systems across the blood-brain barrier (BBB) and the immunosuppressive tumor microenvironment (TME) are two main hurdles for GBM therapy. Herein, a Trojan-horse-like nanoparticle system is designed, which encapsulates biocompatible PLGA-coated temozolomide (TMZ) and IL-15 nanoparticles (NPs) with cRGD-decorated NK cell membrane (R-NKm@NP), to elicit the immunostimulatory TME for GBM chemo-immunotherapy. Taking advantage of the outer NK cell membrane cooperating with cRGD, the R-NKm@NPs effectively traversed across the BBB and targeted GBM. In addition, the R-NKm@NPs exhibited good antitumor ability and prolonged the median survival of GBM-bearing mice. Notably, after R-NKm@NPs treatment, the locally released TMZ and IL-15 synergistically stimulated the proliferation and activation of NK cells, leading to the maturation of dendritic cells and infiltration of CD8+ cytotoxic T cells, eliciting an immunostimulatory TME. Lastly, the R-NKm@NPs not only effectively prolonged the metabolic cycling time of the drugs in vivo, but also has no noticeable side effects. This study may offer valuable insights for developing biomimetic nanoparticles to potentiate GBM chemo- and immuno-therapies in the future.

Ubiquitin-specific peptidase 47 (USP47) regulates cutaneous oxidative injury through nicotinamide nucleotide transhydrogenase (NNT).

Human skin is daily exposed to oxidative stresses in the environment such as physical stimulation, chemical pollutants and pathogenic microorganisms, which are likely to cause skin diseases. As important post-translational modifications, protein ubiquitination and deubiquitination play crucial roles in maintaining cellular homeostasis by the proteolytic removal of oxidized proteins. We have previously reported that the expression of ubiquitin-specific protease 47 (USP47), a kind of deubiquitinating enzymes (DUBs), was significantly elevated in response to oxidative stress. However, the role of USP47 in cutaneous oxidative injury remains unclear. Usp47 wild-type (Usp47+/+) mice and Usp47 knockout (Usp47-/-) mice were used to establish two animal models of oxidative skin damage: (1) radiation- and (2) imiquimod (IMQ)-induced skin injury. Loss of Usp47 consistently aggravated mouse skin damage in vivo. Subsequently, we screened 63 upregulated and 170 downregulated proteins between the skin tissues of wild-type and Usp47-/- mice after 35 Gy electron beam radiation using proteomic analysis. Among the dysregulated proteins, nicotinamide nucleotide transhydrogenase (NNT), which has been reported as a significant regulator of oxidative stress and redox homeostasis, was further investigated in detail. Results showed that NNT was regulated by USP47 through direct ubiquitination mediated degradation and involved in the pathogenesis of cutaneous oxidative injury. Knockdown of NNT expression dramatically limited the energy production ability, with elevated mitochondrial reactive oxygen species (ROS) accumulation and increased mitochondrial membrane potential in irradiated HaCaT cells. Taken together, our present findings illustrate the critical role of USP47 in oxidative skin damage by modulating NNT degradation and mitochondrial homeostasis.

ASE noise mitigation with digital frequency offset loading for discrete spectrum nonlinear frequency division multiplexing systems.

We propose an amplified spontaneous emission (ASE) noise mitigation scheme utilizing digital frequency offset loading (DFO-loading) for discrete spectrum nonlinear frequency division multiplexing (DS-NFDM) systems. Firstly, based on the one-to-one mapping relationship between frequency offsets and eigenvalue positions, the transmitter side encodes 4-bit information onto 16 kinds of different digital frequency offsets. Then, a sliding window-assisted eigenvalue position (SWA-EP) decoding technology is further proposed to substitute the classical channel equalization and carrier phase recovery processes, with the purpose of recovering the original information. The numerical and experimental results demonstrate that, compared with b-coefficient 16 quadrature amplitude modulation (QAM) scheme, Q-factor gains are 2.1 dB under 15 dB optical signal-to-noise ratio (OSNR) and 1.8 dB after 800 km fiber transmission, respectively. Moreover, its complexity is only 0.6% of the b-coefficient scheme. The DFO-loading scheme offers an effective and low-complexity way to mitigate ASE noise of DS-NFDM system.

Mechanoluminescence Affected by Trap Types and Excitation State Positions in Mg3Ca3(PO4)4:Eu2+/Mn2+/Ce3+ for Multimode Anticounterfeiting.

Mechanoluminescence (ML) materials with tunable emissions can serve in many practical applications; however, their underlying mechanism still needs further clarification. Herein, we developed Eu2+-/Mn2+-/Ce3+-activated Mg3Ca3(PO4)4 (MCP) phosphors and studied their luminescence properties by device fabrication. The intense blue ML is obtained by fabricating MCP:Eu2+ into the polydimethylsiloxane elastomer matrix. The red ML of relatively weak intensity is received in Mn2+ activator, but the ML for the Ce3+ dopant is nearly quenched in the same host. The possible reason is proposed from the analysis of the relative positions between the excitation state and conduction band, together with the trap types. The appropriate location of the excited energy levels in the band gap allows for a larger probability of efficient ML when shallow traps near the excitation states are created synchronously as an effective energy transfer (ET) channel. The concentration-dependent ML for the MCP:Eu2+,Mn2+-based devices indicates that the emitting light color can be tailored, where several ET processes among oxygen vacancies, Eu2+, Ce3+, and Mn2+, occur. The luminescence manipulation with dopants and excitation sources demonstrates the potential applications in visualized multimode anticounterfeiting. These findings open up many possibilities for constructing new ML materials by introducing appropriate traps into the band structures.

Transcriptome analysis preliminary reveals the immune response mechanism of golden cuttlefish (Sepia esculenta) larvae exposed to Cd.

As a well-known marine metal element, Cd can significantly affect bivalve mollusk life processes such as growth and development. However, the effects of Cd on the molecular mechanisms of the economically important cephalopod species Sepia esculenta remain unclear. In this study, S. esculenta larval immunity exposed to Cd is explored based on RNA-Seq. The analyses of GO, KEGG, and protein-protein interaction (PPI) network of 1,471 differentially expressed genes (DEGs) reveal that multiple immune processes are affected by exposure such as inflammatory reaction and cell adhesion. Comprehensive analyses of KEGG signaling pathways and the PPI network are first used to explore Cd-exposed S. esculenta larval immunity, revealing the presence of 16 immune-related key and hub genes involved in exposure response. Results of gene and pathway functional analyses increase our understanding of Cd-exposed S. esculenta larval immunity and improve our overall understanding of mollusk immune functions.

Neural System Impairment and Involved Microglia-Neuron Regulation of Broflanilide in Zebrafish Larvae.

Broflanilide is widely used to control pests and has attracted attention due to its adverse effects on aquatic organisms. Our previous study showed that broflanilide has a negative impact on the central nervous system (CNS) at lethal dosages; however, its neural effects under practical situations and the underlying mechanisms remain unknown. To elucidate how broflanilide affects the CNS, we exposed zebrafish larvae to broflanilide at 16.9 and 88.0 µg/L (the environmentally relevant concentrations) for 120 h. Zebrafish locomotion was significantly disturbed at 88.0 µg/L, with a decreased moving distance and velocity accompanied by an inhibited neurotransmitter level. In vivo neuroimaging analysis indicated that the nerves of zebrafish larvae, including the axons, myelin sheaths, and neurons, were impaired. The number of neurons was significantly reduced after exposure, with an impaired morphological structure. These changes were accompanied by the abnormal transcription of genes involved in early CNS development. In addition, an increased total number of microglia and an elevated proportion of amoeboid microglia were observed after 88.0 µg/L broflanilide exposure, pointing out to an upstream role of microglia activation in mediating broflanilide neurotoxicity. Meanwhile, increased inflammatory cytokine levels and brain neutrophil numbers were observed, implicating significant inflammatory response and immune toxicity. Our findings indicate that broflanilide interferes with microglia-neuron regulation and induces neurodevelopmental disorders.

Joint equalization of EEPN, RSOP, and CD with the sliding window assisted extended Kalman filter for a high baud rate Stokes vector direct detection system.

Equalization-enhanced phase noise (EEPN) has emerged as one of the major impairments that cannot be ignored for a high baud rate Stokes vector direct detection (SVDD) system. When EEPN interacts with the rotation of state-of-polarization (RSOP) and chromatic dispersion (CD), the joint impairment effects become even more complicated. To achieve the joint equalization of EEPN, RSOP, and CD impairments of a high baud rate SVDD system, this paper first derives a joint impairment model of these three kinds of impairments, and then proposes a joint equalization scheme of EEPN, RSOP, and CD with a sliding window assisted extended Kalman filter (SWA-EKF). The SWA-EKF scheme first tracks RSOP in the time domain, subsequently compensates CD in the frequency domain, and finally performs EEPN mitigation in the time domain again. The effectiveness of the proposed scheme has been verified by a 60 GBaud SVDD-16QAM simulation system. The results show that when these three impairments are jointly equalized, the SWA-EKF scheme can track RSOP as fast as 3 Mrad/s, cumulative dispersion up to 1600 ps/nm, and EEPN caused by laser linewidth up to 3 MHz. In addition, with an optical signal-to-noise ratio penalty of 0.3 dB, it could increase 35 G baud rate under 3 MHz laser linewidth for the SVDD system. More importantly, its total complexity can be reduced to an order of O(N log N).

Design and Analysis of a Large Mode Field Area and Low Bending Loss Multi-Cladding Fiber with Comb-Index Core and Gradient-Refractive Index Ring.

The large mode field area fiber can raise the tolerance of power, and high requirements for the bending characteristics of optical fibers are needed. In this paper, a fiber composed of a comb-index core, gradient-refractive index ring, and multi-cladding is proposed. The performance of the proposed fiber is investigated by using a finite element method at a 1550 nm wavelength. When the bending radius is 20 cm, the mode field area of the fundamental mode can achieve 2010 µm2, and the bending loss is reduced to 8.452 × 10-4 dB/m. Additionally, when the bending radius is smaller than 30 cm, there are two variations with low BL and leakage; one is a bending radius of 17 cm to 21 cm, and the other is from 24 cm to 28 cm (except for 27 cm). When the bending radius is between 17 cm and 38 cm, the highest bending loss is 1.131 × 10-1 dB/m and the lowest mode field area is 1925 µm2. It has a very important application prospect in the field of high-power fiber lasers and telecom applications.