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1.
Chemosphere ; 238: 124674, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524614

RESUMO

Groundwater discharge from a water spring located along the southwest bank of Yangzonghai Lake, the largest deep plateau-lake with arsenic contamination in a typical karst landform, maybe a potential and on-going source of pollution, but seepage flux has not been investigated. This study applied temperature models to locate sites of groundwater discharge and quantify the magnitude and direction of seepage flux. The contaminant levels and spatial distributions, seasonal seepage flux distributions and the conductivity were investigated. The arsenic concentration of the water spring was 1481.9 µg L-1, and as the distance from the water spring increased, the arsenic concentration in the overlying water, pore-water and surface sediments decreased. Herein, the temperature models of McCallum and Bredehoeft were applied to estimate the lakebed vertical seepage flux in groundwater-surface water exchange systems during a period of 30-day in summer and winter. An upward flow of groundwater discharge was observed near the water spring, with the value of some sites over 10 cm day-1, and a downward flow was observed with increasing distance from the water spring in summer. Additionally, a slight upward flow was observed in winter. The arsenic levels, spatial distributions and the conductivity in monitoring sites were closely related to the seepage flux. The application provided a scientific basis for the prediction of groundwater-surface water exchange in deep plateau-lake and was a further development in temperature models.

2.
J Proteomics ; 210: 103545, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31626998

RESUMO

Targeting specific ubiquitin E3 ligase for degradation of disease-driven protein has recently been an important concept for cancer therapy, as exemplified by the case of thalidomide for the treatment of multiple myeloma. E7070, an aryl sulfonamide drug, exhibited anticancer activity by targeting the E3 ligase receptor DCAF15, with RBM39 as the only known substrate. Exploration of additional substrates of E7070 would facilitate elucidation of its mechanism of actions. To this end, we used a strategy combing pSILAC method with two complementary digestion approaches (LysC-Trypsin and LysN-LysArgiNase) to accurately monitor the protein turnover and increase the depth of proteome profiling. Systematically, we showed that E7070 treatment changed turnover rates of 868 proteins (1.5 fold change and p-value <.05). Several proteins displayed accelerated turnover indicating they were potential new substrates of E7070, among which, pre-mRNA splicing factor 39 (PRPF39) had been reported to be overexpressed in certain cancers. We further demonstrated that PRPF39 was ubiquitinated and degraded by E7070 in a DCAF15-dependent manner, and represented a new bona fide substrate of E7070. The degradation of PRPF39 might also be contributed to the anticancer activity of E7070. SIGNIFICANCE: Identification of degraded substrates is difficult because protein abundance is a comprehensive result regulated by protein production and degradation at the same time. Pulsed SILAC (pSILAC), a method to measure protein turnover, would provide higher sensitivity than total protein quantification. In addition, some peptide sequences are not amenable to MS analysis after LysC-Trypsin digestion. LysN-LysargiNase, as a mirror protease combination of LysC-Trypsin, can be complementary for peptide identification with LysC-Trypsin. By combining pSILAC with two complementary digestion approaches (LysC-Trypsin and LysN-LysArgiNase), we systematically investigated E7070-dependent protein degradation. As a result, we found several potential degradation substrates of E7070 including PRPF39. Further, by exploiting a series of biological assays, we demonstrated that E7070 can lead to the ubiquitination and proteasomal degradation of PRPF39 by promoting the recruitment of PRPF39 to the CUL4-DCAF15 E3 ubiquitin ligase.

3.
Hypertens Res ; 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31685939

RESUMO

This study aimed to explore the association of systolic blood pressure (SBP) trajectories of pregnant women with the risk of adverse outcomes of pregnant women and their fetuses. A register-based cohort of 63,724 pregnant women and their fetuses from January 2013 to December 2017 was investigated. Demographic characteristics, history of disease and family history of disease for pregnant women and perinatal outcomes were recorded, and blood pressure was measured during the whole pregnancy. SBP trajectories were estimated with latent mixture modeling by Proc Traj in SAS using SBP data from the first antenatal care appointment (8-14 weeks), the highest SBP before admission, the admission SBP and the SBP at 2 h postpartum. A censored normal model (CNORM) was considered appropriate, and model fit was assessed using the Bayesian information criterion (BIC). A logistic regression model was used to examine the association between SBP trajectories and the risk of adverse perinatal outcomes. Four distinct SBP trajectory patterns over the pregnancy period were identified and were labeled as low-stable, moderate-stable, high-decreasing and moderate-increasing. Three maternal and three fetal adverse outcomes were selected as the main outcome measures. After adjusting for confounding factors, compared with pregnant women with the low-stable pattern, those with the high-decreasing pattern had a higher risk of developing poor growth outcomes of fetuses, while those with the moderate-increasing pattern had higher risks of developing both adverse maternal and fetal outcomes. Our study results suggest that pregnant women should pay attention to the control of blood pressure throughout pregnancy.

4.
Chin J Nat Med ; 17(10): 738-745, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31703754

RESUMO

Herba Anoectochili is a commonly used medicinal material. However, its adulteration is a serious concern. Due to the similar morphological characteristics of Herba Anoectochili and its adulterants, traditional identification techniques often fail to distinguish between them accurately, which is not conducive to the circulation management and safety of the medicinal materials. To improve the distinction between Herba Anoectochili and its adulterants accurately, this study identified 41 Herba Anoectochili and its adulterant samples based on the ITS2 sequence. Sequence characteristics, Basic Local Alignment Search Tool (BLAST) application, genetic distance, construction of phylogenetic tree, secondary structure prediction, and other methods showed the ITS2 sequence to accurately identify Herba Anoectochili from its adulterants. Furthermore, in this study, we designed a specific primer, based on the ITS2 sequence, and established a real-time PCR detection system for the rapid, sensitive, and specific identification of the original plant of Herba Anoectochili. Compared to DNA barcoding technology, this method has shorter detection time, stronger specificity, and higher sensitivity, which lays the foundation for the rapid identification of Herba Anoectochili.

5.
PLoS One ; 14(11): e0225602, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31756232

RESUMO

Long noncoding RNAs (lncRNAs) have been reported to play key regulatory roles in plant growth, development, and biotic and abiotic stress physiology. Revealing the mechanism of lncRNA regulation in the albino portions of leaves is important for understanding the development of chimeric leaves in Ananas comosus var. bracteatus. In this study, a total of 3,543 candidate lncRNAs were identified, among which 1,451 were differentially expressed between completely green (CGr) and completely white (CWh) leaves. LncRNAs tend to have shorter transcripts, lower expression levels, and greater expression specificity than protein-coding genes. Predicted lncRNA targets were functionally annotated by the Gene Ontology (GO), Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. A lncRNA-mRNA interaction network was constructed, and 36 target mRNAs related to chlorophyll metabolism were predicted to interact with 86 lncRNAs. Among these, 25 significantly differentially expressed lncRNAs putatively interacted with 16 target mRNAs. Based on an expression pattern analysis of the lncRNAs and their target mRNAs, the lncRNAs targeting magnesium chelatase subunit H (ChlH), protochlorophyllide oxidoreductase (POR), and heme o synthase (COX10) were suggested as key regulators of chlorophyll metabolism. This study provides the first lncRNA database for A. comosus var. bracteatus and contributes greatly to understanding the mechanism of epigenetic regulation of leaf albinism.

6.
Molecules ; 24(23)2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31766733

RESUMO

The effects of ultrasonic-assisted extraction (UAE, 200 W, 20 min) on the yield and physicochemical properties of different walnut proteins (WNPs, including albumin, globulin, and glutelin) were investigated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that UAE could result in protein molecular fragmentation of albumin, but did not affect the major bands of globulin and glutelin. The CD spectra demonstrated that different WNPs obtained by UAE had different changes in their secondary structure. Under UAE, there was an increase in surface hydrophobicity (H0) of albumin and gluten and no change in the fluorescence intensity, while decreases were observed in the H0 and fluorescence intensity of globulin; and the contents of total and surface free sulfhydryl in albumin dramatically decreased. UAE reduced the size of the particles and the dimension of the microstructures in albumin and gluten, indicating that ultrasound could unfold protein aggregates. In addition, UAE increased the solubility, emulsifying activity (EA), foaming capacity (FC), and foam stability (FS) of the obtained proteins. The above results indicate that ultrasound extraction is a promising approach to improve the extraction yield and properties of walnut proteins.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31679689

RESUMO

Ischemic stroke is a leading cause of mortality and disability worldwide. Nevertheless, its molecular mechanisms have not yet been adequately illustrated. Progranulin (PGRN) is a secreted glycoprotein with pleiotropic functions. In the present study, we found that PGRN expression was markedly reduced in mice after stroke onset through middle cerebral artery occlusion (MCAO). We also showed that necroptosis was a mechanism underlying cerebral I/R injury. Importantly, PGRN knockdown in vivo significantly promoted the infarction volume and neurological deficits scores in mice after MCAO surgery. Necroptosis induced by MCAO was further accelerated by PGRN knockdown, as evidenced by the promoted expression of phosphorylated receptor-interacting protein (RIP) 1 kinase (RIPK1), RIPK3 and mixed lineage kinase domain-like (MLKL), which was accompanied with increased expression of cleaved Caspase-8 and Caspase-3. However, PGRN over-expression was neuroprotective. Additionally, PGRN-regulated ischemic stroke was related to ROS accumulation that MCAO-mice with PGRN knockdown exhibited severe oxidative stress, as proved by the aggravated malondialdehyde (MDA) and lipid peroxidation (LPO) contents, and the decreased superoxide dismutase (SOD) activity. However, PGRN over-expression in mice with cerebral ischemia showed anti-oxidative effects. Finally, PGRN was found to attenuate oxidative damage partly via its regulatory effects on necroptosis. Therefore, promoting PGRN expression could reduced cerebral I/R-induced brain injury by suppressing neroptosis and associated reactive oxygen species (ROS) production. These data elucidated that PGRN might provide an effective therapeutic treatment for ischemic stroke.

9.
Neuropediatrics ; 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31627234

RESUMO

Muscular dystrophy-dystroglycanopathies (MDDG) are a group of genetically heterogeneous autosomal recessive disorders characterized by hypoglycosylation of α-dystroglycan. Here, we report on two female patients from a consanguineous Lebanese family that presented in early infancy with generalized muscle hypotonia and primary microcephaly. Brain magnetic resonance imaging (MRI) showed different degrees of hypoplasia of the cerebellar vermis and hypoplasia of corpus callosum. Muscle biopsy analyses revealed a muscular dystrophy with reduced expression of α-dystroglycan and merosin in immunoblot analyses. Homozygosity mapping failed to elucidate the causal mutation due to the accepted notion that, in consanguineous families, homozygote mutations cause disease. However, by applying whole exome sequencing, we identified a novel compound heterozygous POMT1 mutation that segregates with the phenotype and is in line with the clinical presentation. This underscores that a less expected compound heterozygous instead of homozygous mutation in a consanguineous marriage results in a recessive disorder and highlights the growing role of next generation sequencing in neuromuscular disorder diagnostics.

10.
Sci Adv ; 5(10): eaax2518, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31633023

RESUMO

The G protein-coupled cysteinyl leukotriene receptor CysLT1R mediates inflammatory processes and plays a major role in numerous disorders, including asthma, allergic rhinitis, cardiovascular disease, and cancer. Selective CysLT1R antagonists are widely prescribed as antiasthmatic drugs; however, these drugs demonstrate low effectiveness in some patients and exhibit a variety of side effects. To gain deeper understanding into the functional mechanisms of CysLTRs, we determined the crystal structures of CysLT1R bound to two chemically distinct antagonists, zafirlukast and pranlukast. The structures reveal unique ligand-binding modes and signaling mechanisms, including lateral ligand access to the orthosteric pocket between transmembrane helices TM4 and TM5, an atypical pattern of microswitches, and a distinct four-residue-coordinated sodium site. These results provide important insights and structural templates for rational discovery of safer and more effective drugs.

11.
J Hematol Oncol ; 12(1): 106, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31640756

RESUMO

BACKGROUND: Cancer/testis antigens (CTAs) are a special type of tumor antigen and are believed to act as potential targets for cancer immunotherapy. METHODS: In this study, we first screened a rational CTA MAGE-A1 for lung adenocarcinoma (LUAD) and explored the detailed characteristics of MAGE-A1 in LUAD development through a series of phenotypic experiments. Then, we developed a novel MAGE-A1-CAR-T cell (mCART) using lentiviral vector based on our previous MAGE-A1-scFv. The anti-tumor effects of this mCART were finally investigated in vitro and in vivo. RESULTS: The results showed striking malignant behaviors of MAGE-A1 in LUAD development, which further validated the rationality of MAGE-A1 as an appropriate target for LUAD treatment. Then, the innovative mCART was successfully constructed, and mCART displayed encouraging tumor-inhibitory efficacy in LUAD cells and xenografts. CONCLUSIONS: Taken together, our data suggest that MAGE-A1 is a promising candidate marker for LUAD therapy and the MAGE-A1-specific CAR-T cell immunotherapy may be an effective strategy for the treatment of MAGE-A1-positive LUAD.

12.
Neurosci Lett ; 714: 134568, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31629034

RESUMO

Recent studies showed that homocysteine (Hcy) levels were obviously elevated in patients with anxiety, furthermore, oxidative stress and inflammation were closely linked with Hcy-related damage. Despite alcohol exposure has differential effects on different forms of anxiety, the role of alcohol on anxiety-related behavior induced by high Hcy levels is still not entirely clear. The present study investigated the protective potential of low-dose alcohol against homocysteine-induced anxiety-related behavior and explored the possible underlying mechanisms. Mice were administered intragastrically with methionine (2.0 g/kg/day) or alcohol (0.6 g/kg/day). After 21 days of administration, the anxiety-related behavior was evaluated through open field (OF) and elevated plus maze (EPM) tests, and the variations of oxidative stress and inflammation levels were measured. The results of OF and EPM tests showed that the anxiety-related behavior in mice was prevented by alcohol treatment. Alcohol lowered the elevated serum Hcy levels and alleviated the damage of hippocampal tissues in hyperhomocysteinemia (HHcy) mice. Meanwhile, the superoxide dismutase (SOD) activity of the hippocampal tissues enhanced, and the malondialdehyde (MDA) concentration of the hippocampal tissues and the serum interleukin-1ß (IL-1ß) level decreased. In addition, after administering alcohol, the increase of superoxide dismutase 1 (SOD1), heme oxygenase 1 (HO-1) protein expression and the decrease of IL-1ß protein expression were also detected in HHcy mice hippocampal tissues. Taken together, low-dose alcohol significantly ameliorated the Hcy-induced anxiety-related behavior in mice, which might be related to SOD1 and HO-1 upregulation and IL-1ß downregulation.

13.
Int J Cancer ; 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31633798

RESUMO

Whether PD-L1-positive patients derive more overall survival benefit from PD-1/PD-L1 inhibitors in the treatment of advanced solid tumours is unclear. We systematically searched the PubMed, Cochrane library and EMBASE databases from January 1, 1966 to March 1, 2019, to identify randomised controlled trials of PD-1/PD-L1 inhibitors (nivolumab, pembrolizumab, atezolizumab, durvalumab and avelumab) that had available hazard ratios (HRs) for death according to PD-L1 status. A random-effects model was used to calculate the pooled overall survival (OS) HR and 95% CI among PD-L1-positive and PD-L1-negative patients. An interaction test was performed to evaluate the heterogeneity between the two estimates. A total of 24 randomised trials, involving 12,966 participants, fulfilled the inclusion criteria. An OS benefit of PD-1/PD-L1 inhibitors was found in both PD-L1-positive patients (HR, 0.65; 95% CI, 0.60-0.70) and PD-L1-negative patients (HR, 0.82; 95% CI, 0.74-0.91) even at the minimum cut-off value of 1%. Significant differences in the efficacy of PD-1/PD-L1 inhibitors between PD-L1-positive and PD-L1-negative patients were noted at different cut-off values. Moreover, there was a positive dose-response relationship between PD-L1 positivity and OS benefit (HR for 1%, 0.58, [0.50, 0.67]; 5%, 0.52 [0.43, 0.64]; 10%, 0.50 [0.40, 0.63]). Subgroup analyses showed that these results were generally consistent, regardless of study design, line of treatment, treatment type, tumour type, PD-L1 staining cell type and median follow-up time. We demonstrated that PD-1/PD-L1 inhibitors significantly improved OS in both PD-L1 positive and PD-L1 negative patients compared to controls, but the magnitude of benefit was clinically PD-L1-dependent.

14.
Anal Chem ; 91(22): 14522-14529, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31634432

RESUMO

Global identification of protein C-termini is highly challenging due to their low abundance in conventional shotgun proteomics. Several enrichment strategies have been developed to facilitate the detection of C-terminal peptides. One major issue of previous approaches is the limited C-terminome coverage. Herein, we integrated LysargiNase digestion, chemical acetylation on neo-N-terminus, and a-ion-aided peptide matching into poly(allylamine)-based C-terminomics (termed as LAACTer). In this strategy, we leveraged LysargiNase, a protease with cleavage specificity N-terminal to Lys and Arg residues, to cover previously unidentifiable C-terminome and employed chemical acetylation and a-ion-aided peptide matching to efficiently boost peptide identifications. Triplicates of LAACTer identified a total of 834 C-termini from proteome of 293T cell, which expanded the coverage by 164% (643 more unique C-termini) compared with the parallel experiments using the original workflow. Compared with the largest human C-terminome data sets (containing 800-900 C-termini), LAACTer not only achieved comparable profiling depth but also yielded 465 previously unidentified C-termini. In a SILAC (stable isotope labeling with amino acids in cell culture)-based quantitative study for identification of GluC-cleaved products, LAACTer quantified 300% more C-terminal peptides than the original workflow. Using LAACTer and the original workflow, we performed global analysis for the C-terminal sequences of 293T cell. The original and processed C-termini displayed distinct sequence patterns, implying the "C-end rules" that regulates protein stability could be more complex than just amino acid motifs. In conclusion, we reason LAACTer could be a powerful proteomic tool for in-depth C-terminomics and would benefit better functional understanding of protein C-termini.

15.
J Environ Manage ; 251: 109621, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31569021

RESUMO

The application of organic fertilizer by farmers is an important method for promoting the transition of agricultural production from increasing the yield to improving the quality and safety of agricultural products and realizing the green development of agriculture. The behavior of farmers can have a direct impact on organic fertilizer application, and the active participation of farmers can effectively reduce moral hazards and improve governance efficiency. A consensus appears to have been reached regarding the importance of land property rights stability (LPRS) for farmers' organic fertilizer application (FOFA) in China; however, few studies have focused on the conditions under which LPRS exerts an effect or the extent of the effect. Moreover, the grain-growing purpose and farm size are rarely included as driving factors underlying the impact of LPRS on FOFA; thus, biased estimations are easily formed. This study analyzed the influence mechanism of LPRS on FOFA and its dependent conditions using the 2017 China Rural Household Panel Survey from Zhejiang University and conducted an empirical analysis via a logit model. The results showed that LPRS could enable farmers to apply organic fertilizer, although the degree of its impact will vary due to differences in the grain-growing purpose and farm size. Currently, selling products is not conducive to the application of organic fertilizer and will reduce the positive impact of LPRS on the application of organic fertilizer by farmers, whereas expanding the farm size will enhance the positive impact of LPRS. The government should constantly improve the methods and channels for realizing high-quality and high-priced agricultural products and fully acknowledge the role of market demand in guiding farmers' agricultural production, which will increase their enthusiasm for organic fertilizer application. The government should also improve the contract management system for land transfer to strengthen the ability of farmers to expand their farm size to fully demonstrate the role of large-scale farmers.


Assuntos
Fazendeiros , Fertilizantes , Agricultura , China , Fazendas , Humanos , Propriedade
16.
World Neurosurg ; 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31493599

RESUMO

OBJECTIVE: To identify and reveal the sensitivity and efficiency of dynamic somatosensory evoked potentials (DSSEPs) in the diagnosis of cervical spondylotic myelopathy (CSM). METHODS: This retrospective study included 31 CSM and 15 control patients. All patients received SSEP examination with stimulation of median and ulnar nerves at neutral, flexed, and extended cervical positions; latency and amplitude were recorded at the C2 and C5 spinous processes and in the scalp over the primary sensory area (C3'/4'). The percentage changes in latency and amplitude with dynamic motion were examined for each lead and compared between groups; the diagnostic cutoff values were determined using receiver operating characteristic curve analysis. RESULTS: All the patients with CSM received surgeries and were followed up for 1 year. Amplitude parameters varied with a dynamic position in both groups; all recorded dynamic SSEP indices except right median stimulus recorded at C5 spinous process, right ulnar stimulus recorded at scalp point C3, and right ulnar stimulus recorded at C2 spinous process were significantly different between groups (P < 0.05), but latency was not (P > 0.05). At the neutral position, the amplitude of left media stimulus recorded at C2 spinous process (LMC2) was associated with CSM, but with low diagnostic accuracy (area under the curve = 0.199). At a dynamic position, the percentage change in amplitude of LMC2 and of left ulnar stimulus recorded at C2 spinous process (LUC2) were determined to be diagnostic of CSM (P < 0.05), with areas under the curve of 0.891 and 0.912, respectively. Both records had high sensitivity and specificity in the diagnosis of CSM; the diagnostic cutoff values of LMC2 and LUC2 were calculated as 10.2% and 19.25%, respectively. CONCLUSIONS: The percentage change in amplitude was obvious during cervical dynamic motion, with records from LMC2 and LUC2 being predictive of CSM diagnosis; dynamic SSEPs provided a simple, accurate, and noninvasive supplementary test for the diagnosis of complicated CSM.

17.
Opt Express ; 27(17): 23775-23784, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31510277

RESUMO

A silicon/silicon-rich nitride hybrid-core waveguide has been proposed and experimentally demonstrated for nonlinear applications to fill the gap between the pure silicon waveguide and the pure silicon nitride waveguide with respect to the nonlinear properties. The hybrid-core waveguide presented here leverages the advantages of the silicon and the silicon-rich nitride waveguide platforms, showing a large nonlinearity γ of 72 ± 5 W-1 m-1 for energy-efficient four-wave mixing wavelength conversion. At the same time, the drawbacks of the material platforms are dramatically mitigated, exhibiting a reduced two-photon absorption coefficient ßTPA of 0.023 cm/GW resulting in an increased nonlinear figure-of-merit as large as 21.6. A four-wave-mixing conversion efficiency as large as -5.3 dB has been achieved with the promise to be larger than 0 dB. These findings are strong arguments supporting the silicon/silicon-rich nitride hybrid-core waveguide to be used for energy-efficient nonlinear photonic applications.

18.
Opt Express ; 27(14): 19156-19167, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31503679

RESUMO

In this paper, we propose a nonlinear Tomlinson-Harashima pre-coding (THP) scheme for nonlinear distortion suppression in direct-detected double sideband (DSB) PAM-4 transmission systems. Based on the traditional THP, the feedback term is modified by introducing nonlinear components. In this way, more accurate feedback can be obtained to mitigate the signal distortions, especially the nonlinear distortions including the signal-to-signal beating interference and nonlinear power series caused by chromatic dispersion and square-law detection. Meanwhile, we also propose to only reserve the nonlinear kernels with adjacent tap products in nonlinear THP, for the purpose of computation complexity reduction. To verify the effectiveness, transmissions of double sideband (DSB) PAM-4 signal in 1550nm window are experimentally demonstrated. Volterra FFE is adopted on the receiver side to suppress linear and nonlinear pre-cursors. We optimize various parameters of hardware and apply appropriate simplification to the nonlinear THP kernels. The results indicate that, the proposed nonlinear THP can lead to up to three folds BER reduction, compared to the conventional linear THP. Finally, with the combination of proposed nonlinear THP and conventional Volterra FFE, we successfully transmit 84-Gbps PAM-4 and 107-Gbps PAM-4 respectively over 80 km and 40 km under the hard decision forward error correction (HD-FEC) threshold of 3.8 × 10-3.

19.
Appl Opt ; 58(22): 6091-6097, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31503932

RESUMO

Owing to its material properties, aluminum-based optical loads are widely used in the aerospace field. At present, the main processing of an aluminum alloy mirror is single-point diamond turning followed by the combined polishing process. The surface will generate some white crystals during the chemical mechanical polishing process (CMP). These crystals can affect the improvement of surface quality and seriously reduce the processing efficiency of the whole process. In view of the above problems, four main factors of crystallization are obtained by interface theoretical analysis, Visual MINTEQ simulation of chemical morphological distribution, and experimental analysis. They are temperature, PH value of polishing fluid, solid-liquid contact angle, and impurity content of aluminum alloy. The crystallization phenomenon in the polishing process is successfully suppressed by improving the polishing process and selecting new materials. The experimental results showed that the surface roughness decreased from 7.21 to 2.98 nm without crystallization using the new method.

20.
Sensors (Basel) ; 19(19)2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31561597

RESUMO

Balancing the accuracy and speed of three-dimensional (3D) surface measurement of objects is crucial in many important applications. In this paper, we present a wrapped phase and pseudorandom image method and develop an experimental system aiming to avoid the process of phase unwrapping. Our approach can reduce the length of image sequences and improve the speed of pattern projection and image acquisition and can be used as a good candidate for high-speed 3D measurement. The most critical step in our new methodology is using the wrapped phase and the epipolar constraint between one camera and a projector, which can obtain several candidate 3D points within the measurement volume (MV). The false points from the obtained candidate 3D points can be eliminated by the pseudorandom images. A systematic accuracy with MV better than 0.01 mm is achievable. 3D human body measurement results are given to confirm the fast speed of image acquisition capability.

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