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1.
IEEE Trans Cybern ; 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32356771

RESUMO

Spikes are the currency in central nervous systems for information transmission and processing. They are also believed to play an essential role in low-power consumption of the biological systems, whose efficiency attracts increasing attentions to the field of neuromorphic computing. However, efficient processing and learning of discrete spikes still remain a challenging problem. In this article, we make our contributions toward this direction. A simplified spiking neuron model is first introduced with the effects of both synaptic input and firing output on the membrane potential being modeled with an impulse function. An event-driven scheme is then presented to further improve the processing efficiency. Based on the neuron model, we propose two new multispike learning rules which demonstrate better performance over other baselines on various tasks, including association, classification, and feature detection. In addition to efficiency, our learning rules demonstrate high robustness against the strong noise of different types. They can also be generalized to different spike coding schemes for the classification task, and notably, the single neuron is capable of solving multicategory classifications with our learning rules. In the feature detection task, we re-examine the ability of unsupervised spike-timing-dependent plasticity with its limitations being presented, and find a new phenomenon of losing selectivity. In contrast, our proposed learning rules can reliably solve the task over a wide range of conditions without specific constraints being applied. Moreover, our rules cannot only detect features but also discriminate them. The improved performance of our methods would contribute to neuromorphic computing as a preferable choice.

2.
Nanoscale ; 12(19): 10426-10429, 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32393940
3.
Sci Rep ; 10(1): 8323, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32433485

RESUMO

Viral infections trigger host innate immune responses, characterized by the production of type-I interferons (IFN) including IFNß. IFNß induces cellular antiviral defense mechanisms and thereby contributes to pathogen clearance. Accumulating evidence suggests that mitochondria constitute a crucial platform for the induction of antiviral immunity. Here we demonstrate that the mitochondrial protein phosphoglycerate mutase family member 5 (PGAM5) is important for the antiviral cellular response. Following challenge of HeLa cells with the dsRNA-analog poly(I:C), PGAM5 oligomers and high levels of PGAM5 were found in mitochondrial aggregates. Using immunoprecipitation, a direct interaction of PGAM5 with the mitochondrial antiviral-signaling protein (MAVS) was demonstrated. In addition, PGAM5 deficient cells showed diminished expression of IFNß and IFNß target genes as compared to WT cells. Moreover, PGAM5 deficient mouse embryonic fibroblasts (MEFs) exhibited decreased phosphorylation levels of IRF3 and TBK1 when challenged with poly(I:C) intracellularly. Finally, PGAM5 deficient MEFs, upon infection with vesicular stomatitis virus (VSV), revealed diminished IFNß expression and increased VSV replication. Collectively, our study highlights PGAM5 as an important regulator for IFNß production mediated via the TBK1/IRF3 signaling pathway in response to viral infection.

5.
J Cell Mol Med ; 24(9): 5224-5237, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32233073

RESUMO

Liver fibrosis, a consequence of unhealthy modern lifestyles, has a growing impact on human health, particularly in developed countries. Here, we have explored the anti-fibrotic effects of propylene glycol alginate sodium sulphate (PSS), a natural extract from brown algae, in fibrotic mice and cell models. Thus, we established bile duct ligature and carbon tetrachloride mouse models and LX-2 cell models with or without PSS treatment. Liver pathological sections and the relevant indicators in serum and liver tissues were examined. PSS prevented hepatic injury and fibrosis to a significant extent, and induced up-regulation of matrix metalloproteinase-2 and down-regulation of tissue inhibitor of metalloproteinase-1 through suppressing the transforming growth factor ß1 (TGF-ß1)/Smad pathway. PSS additionally exerted an anti-autophagy effect through suppressing the Janus kinase (JAK) 2/transducer and activator of transcription 3 (STAT3) pathway. In conclusion, PSS prevents hepatic fibrosis by suppressing inflammation, promoting extracellular matrix (ECM) decomposition and inactivating hepatic stellate cells through mechanisms involving the TGF-ß1/Smad2/3 and JAK2/STAT3 pathways in vivo and in vitro.

6.
Food Chem Toxicol ; 140: 111321, 2020 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-32289334

RESUMO

Lipopolysaccharide (LPS)-induced inflammatory macrophages model and intestinal-like Caco-2/macrophages co-culture inflammation model were established to evaluate the anti-inflammatory effect and underlying mechanism of Ganoderma atrum polysaccharides (PSG-1). It was found that PSG-1 reduced LPS-induced secretion of pro-inflammatory cytokine (TNF-α, IL-6 and IL-1ß), ROS levels, and inhibited the expression of COX-2 in LPS-stimulated inflammatory macrophages model and intestinal-like Caco-2/macrophages co-culture inflammation model. Furthermore, PSG-1 suppressed the LPS-induced activation of MAPKs signaling pathways, and regulated oxidative stress by activating the Nrf2/Keap1 signaling pathways. These above results indicated that PSG-1 not only has a direct anti-inflammatory effect in LPS-induced inflammatory macrophages model, but also has an indirect anti-inflammatory effect in intestinal-like Caco-2/macrophages co-culture inflammation model. These findings provide new insight of the mechanism underlying the anti-inflammatory activities of PSG-1, and facilitated the expansion of the application of PSG-1 in natural functional food.

7.
Int Immunopharmacol ; 84: 106529, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32344356

RESUMO

OBJECTIVE: The study was aimed to explore the hepatocellular protective functions of cafestol during hepatic ischemia-reperfusion injury and the possible mechanisms. METHODS: Ninety male Balb/c mice were randomly divided into seven groups, including normal control group, L-cafestol(20mg/kg) group, H-cafestol(40mg/kg) group, sham group, IR group, L-cafestol(20mg/kg) + IR group, H-cafestol(40mg/kg) + IR group. Serum liver enzymes (ALT, AST), inflammation mediators, proteins associated with apoptosis and autophagy, indicators linked with ERK/PPARγ pathway, and liver histopathology were measured using ELISA, qRT-PCR, immunohistochemical staining, and western blotting at 2, 8, and 24 hours after reperfusion. RESULTS: Our findings confirmed that cafestol preconditioning groups could reduce the levels of ALT and AST, alleviate liver pathological damage, suppress the release of inflammation mediators, inhibit the production of pro-apoptosis protein including caspase-3, caspase-9 and Bax, decrease the expression of autophagy-linked protein including Beclin-1 and LC3, increase anti-apoptosis protein Bcl-2, and restrain the activation of ERK and PPARγ. CONCLUSION: Cafestol preconditioning could attenuate inflammatory response, apoptosis and autophagy on hepatic ischemia reperfusion injury by suppressing ERK/PPARγ pathway.

8.
Sci Total Environ ; 724: 138162, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32247977

RESUMO

Recurring drought has caused large crop yield losses in Australia during past decades. Long-term drought forecasting is of great importance for the development of risk management strategies. Recently, large-scale climate drivers (e.g. El Niño-Southern Oscillation) have been demonstrated as useful in the application of drought forecasting. Machine learning-based models that use climate drivers as input are commonly adopted to provide drought forecasts as these models are easy to develop and require less information compared to physical-based models. However, few machine learning-based models have been developed to forecast drought conditions during growing season across all Australian cropping areas. In this study, we developed a growing season (Apr.-Nov.) meteorological drought forecasting model for each climate gauging location across the Australian wheatbelt based on multiple lagged (past) large-scale climate indices and the Random Forest (RF) algorithm. The Standardized Precipitation Index (SPI) was used as the response variable to measure the degree of meteorological drought. Results showed that the RF model could provide satisfactory drought forecasts in the eastern areas of the wheatbelt with Pearson's correlation coefficient r > 0.5 and normalized Root Mean Square Error (nRMSE) < 23%. Forecasted drought maps matched well with observed drought maps for three representative periods. We identified NINO3.4 sea surface temperature and Multivariate ENSO Index as the most influential indices dominating growing season drought conditions across the wheatbelt. In addition, lagged impacts of large-scale climate drivers on growing season drought conditions were long-lasting and the indices in previous year could also potentially affect drought conditions during current year. As large-scale climate indices are readily available and can be rapidly used to feed data driven models, we believe the proposed meteorological drought forecasting models can be easily extended to other regions to provide drought outlooks which can help mitigate adverse drought impacts.

9.
J Dairy Sci ; 103(5): 4252-4261, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32147261

RESUMO

Liquid hot water (LHW) treatment can be used to disrupt the fiber structure of rice straw. This in vitro ruminal batch culture study investigated the effect of LHW treatment on feed degradation, methane (CH4) production, and microbial populations. Rice straw was treated by LHW, and in vitro ruminal fermentation was performed using an automatic system with 72 h of incubation. Scanning electron microscopy showed that LHW treatment disrupted the physical structure of rice straw. Liquid hot water treatment decreased neutral detergent fiber and hemicellulose contents of the rice straw and increased neutral detergent solubles, water-soluble carbohydrates, and arabinose contents. Liquid hot water treatment increased dry matter degradation and volatile fatty acid concentration and decreased the acetate:propionate ratio, CH4 production, hydrogen accumulation, neutral detergent fiber degradation, and populations of protozoa, fungi, and cellulolytic bacteria. In summary, LHW treatment disrupted the cellulose-hemicellulose-lignin structure matrix of rice straw, leading to increased substrate degradability and decreased CH4 production. Therefore, the LHW treatment is a potential strategy to improve the nutritive value of forage such as rice straw and decrease the CH4 emissions in ruminants.

10.
Chem Commun (Camb) ; 56(32): 4488-4491, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32202284

RESUMO

Cobalt decorated nitrogen-doped carbon bowls (Co@NCB) have been successfully constructed by impregnating bowl-like resin particles with cobalt salt followed by annealing. The cobalt exists in the following two forms in the obtained Co@NCB: Co nanoparticles and CoN4. The Co@NCB outperforms the commercial Pt/C in the oxygen reduction reaction in terms of half-wave potential and stability. When Co@NCB is applied in zinc-air batteries, a high open-circuit voltage, excellent power density, and satisfactory stability are achieved.

11.
Medicine (Baltimore) ; 99(13): e19591, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32221078

RESUMO

To systematically analyze the potential of embryo implantation through comparison between the number of surviving blastomeres, the growth, and implantation rate.Retrospective analysis on implantation rate and the growth of prefreeze-postthaw embryos with different blastomeres in 1487 frozen embryo transfer cycles.In groups of postthaw embryos without damage, implantation rate and the average number of blastomere growth increased significantly with increasing number of blastomeres. The implantation rate and the number of blastomeres of embryos with 8-8c (the number of blastomeres in prefreeze embryo-the number of blastomeres in postthaw embryo) continued to grow at a significantly higher rate than that of 5-5c and 6-6c (P < .05). In groups of embryos with the same number of blastomeres before freezing and with partial damage after resuscitation, the implantation rates were lower and the average numbers of blastomere growth reduced as the number of damaged blastomeres increased. For embryos with good quality before freezing, 1 to 3 damaged blastomeres in postthawed embryos did not affect the development and implantation rate. Both implantation rate and growth rate of embryos with 8-6c were significantly higher than those of embryos with 6-6c (P < .05).The number of surviving blastomeres and growth in frozen-thawed embryos could be important index to predict embryo development potential and clinical outcome of implantation. For embryos with good quality, a small amount of damaged blastomeres would not weaken embryo development potential and implantation rate after being thawed.


Assuntos
Blastômeros/metabolismo , Criopreservação , Implantação do Embrião/fisiologia , Embrião de Mamíferos/metabolismo , Fatores Etários , Endométrio/citologia , Estradiol/sangue , Feminino , Humanos , Mórula/metabolismo , Estudos Retrospectivos
12.
Nanoscale ; 12(14): 7804-7813, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32219265

RESUMO

It is important to maintain the balance between therapeutic efficiency and cytotoxicity when using nanomaterials for biomedical applications. Here, we propose a new method (i.e., non-covalent coating of protected copolymers onto the nanoparticle surface) to enhance the active targeting of nanoparticles to the cancer cells by combining the dissipative particle dynamics simulation and in vitro experiments. When coating the protected copolymer onto the nanoparticle surface, the uptake efficiency could be greatly altered due to the competition between the copolymer-ligand interaction and the receptor-ligand interaction-the non-covalent coating is more efficient than the covalent coating. Furthermore, the effect of the physicochemical properties of the protected copolymer on the targeting ability of nanoparticles was also investigated. This study offers useful insight into the optimal design of nanocarriers in biomedicine.

13.
Artigo em Inglês | MEDLINE | ID: mdl-32203038

RESUMO

The capability for environmental sound recognition (ESR) can determine the fitness of individuals in a way to avoid dangers or pursue opportunities when critical sound events occur. It still remains mysterious about the fundamental principles of biological systems that result in such a remarkable ability. Additionally, the practical importance of ESR has attracted an increasing amount of research attention, but the chaotic and nonstationary difficulties continue to make it a challenging task. In this article, we propose a spike-based framework from a more brain-like perspective for the ESR task. Our framework is a unifying system with consistent integration of three major functional parts which are sparse encoding, efficient learning, and robust readout. We first introduce a simple sparse encoding, where key points are used for feature representation, and demonstrate its generalization to both spike- and nonspike-based systems. Then, we evaluate the learning properties of different learning rules in detail with our contributions being added for improvements. Our results highlight the advantages of multispike learning, providing a selection reference for various spike-based developments. Finally, we combine the multispike readout with the other parts to form a system for ESR. Experimental results show that our framework performs the best as compared to other baseline approaches. In addition, we show that our spike-based framework has several advantageous characteristics including early decision making, small dataset acquiring, and ongoing dynamic processing. Our framework is the first attempt to apply the multispike characteristic of nervous neurons to ESR. The outstanding performance of our approach would potentially contribute to draw more research efforts to push the boundaries of spike-based paradigm to a new horizon.

14.
BMC Plant Biol ; 20(1): 129, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32220242

RESUMO

BACKGROUND: Pear is one of the most important fruit crops worldwide. Anthocyanins and procyanidins (PAs) are important secondary metabolites that affect the appearance and nutritive quality of pear. However, few studies have focused on the molecular mechanism underlying anthocyanin and PA accumulation in pear. RESULTS: We conducted metabolome and transcriptome analyses to identify candidate genes involved in anthocyanin and PA accumulation in young fruits of the pear cultivar 'Clapp Favorite' (CF) and its red mutation cultivar 'Red Clapp Favorite' (RCF). Gene-metabolite correlation analyses revealed a 'core set' of 20 genes that were strongly correlated with 10 anthocyanin and seven PA metabolites. Of these, PcGSTF12 was confirmed to be involved in anthocyanin and PA accumulation by complementation of the tt19-7 Arabidopsis mutant. Interestingly, PcGSTF12 was found to be responsible for the accumulation of procyanidin A3, but not petunidin 3, 5-diglucoside, opposite to the function of AtGSTs in Arabidopsis. Transformation with PcGSTF12 greatly promoted or repressed genes involved in anthocyanin and PA biosynthesis, regulation, and transport. Electrophoretic mobility shift and luciferase reporter assays confirmed positive regulation of PcGSTF12 by PcMYB114. CONCLUSION: These findings identify a core set of genes for anthocyanin and PA accumulation in pear. Of these, PcGSTF12, was confirmed to be involved in anthocyanin and PA accumulation. Our results also identified an important anthocyanin and PA regulation node comprising two core genes, PcGSTF12 and PcMYB114. These results provide novel insights into anthocyanin and PA accumulation in pear and represent a valuable data set to guide future functional studies and pear breeding.

15.
Int J Biol Macromol ; 152: 766-774, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32119945

RESUMO

In this study, the immune responses of Mesona chinensis Benth polysaccharides (MP) in vitro and in vivo were investigated. Results showed that MP presented immunomodulatory activities on macrophages and T lymphocytes in vitro. Compared with the cyclophosphamide (Cy)-induced immunosuppressive mice, the body weights, spleen indexes (3.45 to 4.91) and thymus indexes (0.78 to 1.04) of the mice treated with MP were increased, and the peripheral blood levels were recovered. MP treatment also increased superoxide dismutase, glutathione peroxidase and catalase activities, and reduced malondialdehyde levels to enhance the total antioxidant capacity of Cy-treated mice. In addition, MP significantly elevated IL-2, NO, and IFN-γ secretions of splenic lymphocytes and spleen, while MP mainly exerts an immune effect by regulating T lymphocytes. Furthermore, MP possessed the immunomodulatory activity by up-regulating the phosphorylation levels of proteins factors (c-Jun N-terminal kinase, extracellular regulated protein kinase and p38 kinase) in mitogen activated protein kinases signaling pathways. This study suggested that MP may be explored as a natural immune stimulant for functional food and nutraceutical industries.

16.
Carbohydr Polym ; 235: 115957, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32122493

RESUMO

The present study aimed to investigate the protective effect of cultured Cordyceps sinensis polysaccharides (CSP) on cyclophosphamide (Cy)-induced intestinal mucosal immunosuppression and microbial dysbiosis in mice. Results showed that CSP stimulated cytokines secretion (IL-12, IFN-γ, IL-4, IL-13, IL-6, IL-17, IL-10, TGF-ß3, TNF-α, IL-2, IL-21) and transcription factors production (T-bet, GATA-3, RORγt, Foxp3). TLRs (TLR-2, TLR-4, TLR-6) and NF-κB pathway key proteins (p-IκB-α, NF-κB p65) were also upregulated after CSP administration. Moreover, CSP recovered SCFAs levels which decreased by Cy treatment. Furthermore, 16S rRNA sequencing of fecal samples was performed. α-diversity and ß-diversity analysis revealed CSP improved microbial community diversity and modulated the overall structure of gut microbiota. Taxonomic composition analysis found that CSP increased the abundance of probiotics (Lactobacillus, Bifidobacterium, Bacteroides) and decreased pathogenic bacteria (Clostridium, Flexispira). These findings suggested the potential of CSP as a prebiotics to reduce side effects of Cy on intestinal mucosal immunity and gut microbiota.

17.
Food Chem Toxicol ; 138: 111244, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32151603

RESUMO

The aim of this study was to investigate the protective effect and underlying mechanisms of Ganoderma atrum polysaccharide (PSG-1) on cyclophosphamide (Cy)-induced intestinal mucosal dysfunction in mice. Results showed that PSG-1 promoted the formation of IgA-secreting cells, modulated sIgA, IgE, IgG, IgM secretion, and improved TLR-2, TLR-4, TLR-6 mRNA levels while these factors were suppressed after Cy treatment. CD4+ and CD8+ T cell numbers were also elevated by PSG-1. Cytokines including IFN-γ, TNF-α, IL-2, IL-12p70, IL-4, IL-1ß, IL-17, IL-21, IL-23, TGF-ß3 and transcription factors including T-bet, GATA-3, RORγt, Foxp3 increased after PSG-1 administration. Besides, PSG-1 reversed goblet cell numbers, and upregulated tight junction proteins like ZO-1, occludin and claudin-1 in immunosuppressed mice. Apart from these, the autophagy-related proteins LC3, Beclin-1, Atg5 and Atg7 were enhanced by PSG-1. These findings demonstrated that PSG-1 could ameliorate Cy-induced impairment of intestinal immunity and mucosal integrity, which maybe associated with autophagy in mice.

18.
Neuropharmacology ; 168: 108018, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32113967

RESUMO

Genome-wide screening approaches identified the cell adhesion molecule Cadherin-13 (CDH13) as a risk factor for neurodevelopmental disorders, nevertheless the contribution of CDH13 to the disease mechanism remains obscure. CDH13 is involved in neurite outgrowth and axon guidance during early brain development and we previously provided evidence that constitutive CDH13 deficiency influences the formation of the raphe serotonin (5-HT) system by modifying neuron-radial glia interaction. Here, we dissect the specific impact of CDH13 on 5-HT system development and function using a 5-HT neuron-specific Cdh13 knockout mouse model (conditional Cdh13 knockout, Cdh13 cKO). Our results show that exclusive inactivation of CDH13 in 5-HT neurons selectively increases 5-HT neuron density in the embryonic dorsal raphe, with persistence into adulthood, and serotonergic innervation of the developing prefrontal cortex. At the behavioral level, adult Cdh13 cKO mice display delayed acquisition of several learning tasks and a subtle impulsive-like phenotype, with decreased latency in a sociability paradigm alongside with deficits in visuospatial memory. Anxiety-related traits were not observed in Cdh13 cKO mice. Our findings further support the critical role of CDH13 in the development of dorsal raphe 5-HT circuitries, a mechanism that may underlie specific clinical features observed in neurodevelopmental disorders.

19.
Langmuir ; 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32216353

RESUMO

The self-assembly of oppositely charged colloidal ellipsoids and spheres under active confinement is first proposed to achieve long-range ordered photonic crystals. Compared with the conventional passive confinement, a characteristic of the active confinement is that boundaries are movable. Our Brownian dynamics simulations show that dynamic steady structures, similar to quasi-2D colloidal crystals, can be obtained under the strong confinement when the two boundaries periodically oscillate together. The in-plane structures can be regulated by changing the charge ratio of the two kinds of particles. These dynamic steady structures are determined by the minimum electrostatic energy with the aid of increased mobility of confined particles, which are not available in equilibrium. Numerical simulations verify that light can be perfectly confined in this dielectric binary photonic slab without any radiation, which corresponds to a typical optical bound state with divergent lifetime and ultrasharp spectral profile. Given the changeable geometry of this photonic slab, the trapped optical field might be applicable to enhanced light-matter interactions. In addition, for thicker layers, layer-by-layer ordered structures occur spontaneously, driven by the active confinement, while no global order occurs in the passive confinement. Our results show that the boundary motion can become an important factor affecting self-assembled structure and function.

20.
J Hazard Mater ; 391: 122209, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32036314

RESUMO

Understanding bacterial metal detoxification systems is crucial for determining the environmental impacts of metal pollution and for developing advanced bioremediation and water disinfection strategies. Here, we explore the role of cell surface sulfhydryl sites in bacterial detoxification of Cd, using Pseudomonas putida with surface sulfhydryl sites mostly on its EPS molecules as a model organism. Our results show that 5 and 20 ppm Cd in LB growth medium affects the lag phase of P. putida, but not the overall extent of cell growth at stationary phase, indicating that P. putida can detoxify Cd at these concentrations. EXAFS analysis of Cd bound to biomass from the different growth stages indicates that Cd binds to both sulfhydryl and non-sulfhydryl sites, but that the importance of Cd-sulfhydryl binding increases from early exponential to stationary phase. Cell growth is positively correlated to the measured sulfhydryl concentration on different biomass samples, but is independent of the measured non-sulfhydryl binding site concentration on the cell surfaces. Taken together, our results demonstrate that the sulfhydryl binding sites on EPS molecules can play an important role in binding and detoxifying toxic metals, significantly decreasing the bioavailability of the metal by sequestering it away from the bacterial cells.

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