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Soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems and plays a crucial role in mitigating climate change and enhancing soil productivity. Microbial-derived carbon (MDC) is the main component of the persistent SOC pool. However, current formulas used to estimate the proportional contribution of MDC are plagued by uncertainties due to limited sample sizes and the neglect of bacterial group composition effects. Here, we compiled the comprehensive global dataset and employed machine learning approaches to refine our quantitative understanding of MDC contributions to total carbon storage. Our efforts resulted in a reduction in the relative standard errors in prevailing estimations by an average of 71% and minimized the effect of global variations in bacterial group compositions on estimating MDC. Our estimation indicates that MDC contributes approximately 758 Pg, representing approximately 40% of the global soil carbon stock. Our study updated the formulas of MDC estimation with improving the accuracy and preserving simplicity and practicality. Given the unique biochemistry and functioning of the MDC pool, our study has direct implications for modeling efforts and predicting the land-atmosphere carbon balance under current and future climate scenarios.
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Carbono , Microbiologia do Solo , Solo , Carbono/metabolismo , Carbono/análise , Solo/química , Incerteza , Mudança Climática , Ecossistema , Bactérias/metabolismo , Sequestro de Carbono , Aprendizado de Máquina , Ciclo do CarbonoRESUMO
BACKGROUND: Brassica napus L. (B. napus) is susceptible to waterlogging stress during different cultivation periods. Therefore, it is crucial to enhance the resistance to waterlogging stress to achieve a high and stable yield of B. napus. RESULTS: Here we observed significant differences in the responses of two B. napus varieties in root under waterlogging stress. The sensitive variety (23651) exhibited a more pronounced and rapid reduction in cell wall thickness and root integrity compared with the tolerant variety (Santana) under waterlogging stress. By module clustering analysis based on transcriptome data, we identified that cell wall polysaccharide metabolism responded to waterlogging stress in root. It was found that pectin content was significantly reduced in the sensitive variety compared with the tolerant variety. Furthermore, transcriptome analysis revealed that the expression of two homologous genes encoding polygalacturonase-inhibiting protein 2 (PGIP2), involved in polysaccharide metabolic pathways, was highly upregulated in root of the tolerant variety under waterlogging stress. BnaPGIP2s probably confer waterlogging resistance by inhibiting the activity of polygalacturonases (PGs), which in turn reduces the degradation of the pectin backbone polygalacturonic acid. CONCLUSIONS: Our findings demonstrate that cell wall polysaccharides in root plays a vital role in response to the waterlogging stress and provide a theoretical foundation for breeding waterlogging resistance in B. napus varieties.
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Brassica napus , Parede Celular , Raízes de Plantas , Polissacarídeos , Estresse Fisiológico , Brassica napus/fisiologia , Brassica napus/genética , Parede Celular/metabolismo , Polissacarídeos/metabolismo , Raízes de Plantas/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Pectinas/metabolismo , Água/metabolismoRESUMO
BACKGROUND AND AIMS: Distinctive gut microbial profiles have been observed between patients with Wilson disease (WD) and healthy individuals. Despite this, the exact relationship and influence of gut microbiota on the advancement of WD-related liver damage remain ambiguous. This research seeks to clarify the gut microbiota characteristics in both human patients and mouse models of WD, as well as their impact on liver injury. METHODS: Gut microbial features in healthy individuals, patients with WD, healthy mice and mice with early- and late-stage WD were analysed using 16S rRNA gene sequencing. Additionally, WD-afflicted mice underwent treatment with either an antibiotic cocktail (with normal saline as a control) or healthy microbiota (using disease microbiota as a control). The study assessed gut microbiota composition, hepatic transcriptome profiles, liver copper concentrations and hepatic pathological injuries. RESULTS: Patients with hepatic WD and mice with WD-related liver injury displayed altered gut microbiota composition, notably with a significant reduction in Lactobacillus abundance. Additionally, the abundances of several gut genera, including Lactobacillus, Veillonella and Eubacterium coprostanoligenes, showed significant correlations with the severity of liver injury in patients with WD. In WD mice, antibiotic treatment or transplantation of healthy microbiota altered the gut microbial structure, increased Lactobacillus abundance and modified the hepatic transcriptional profile. These interventions resulted in reduced hepatic copper concentration and alleviation of WD-related liver injury. CONCLUSIONS: Individuals and mice with pronounced WD-related liver injury exhibited shifts in gut microbial composition. Regulating gut microbiota through healthy microbiota transplantation emerges as a promising therapeutic approach for treating WD-related liver injury.
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INTRODUCTION: Wernekinck commissure syndrome (WCS) is an extremely rare midbrain syndrome, which selectively destroys the decussation of the superior cerebellar peduncle and the central tegmental tract, which commonly presents with bilateral cerebellar ataxia, dysarthria, and internuclear ophthalmoplegia. Palatal myoclonus in Wernekinck commissure syndrome is uncommon and often occurs as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. MATERIAL AND METHOD: A patient with WCS, admitted to our hospital from December 2023, was chosen for this study, and the syndrome's clinical manifestations, imaging features, and etiology were retrospectively analyzed based on the literature. A 68-year-old right-handed East Asian man presented with dizziness, slurred speech, difficulty with swallowing and walking, and rhythmic contractions of the soft palate. He had several risk factors for ischemic cerebrovascular diseases (age, sex, dyslipidemia, hypertension and smoking history). Brain magnetic resonance imaging showed hyperintensity of DWI and hypointensity of ADC at the caudal midbrain which was around the paramedian mesencephalic tegmentum anterior to the aqueduct of midbrain. RESULTS: He was diagnosed with Wernekinck commissure syndrome (WCS) secondary to caudal paramedian midbrain infarction. He was started on dual antiplatelet therapy (aspirin and clopidogrel) and intensive statin therapy. Blood pressure and glucose were also adjusted. His symptoms improved rapidly, and he walked steadily and speak clearly after 7 days of treatment. CONCLUSIONS: Palatal myoclonus is known to occur as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. However, Our case suggests that palatal myoclonus can occur in the early stages in WCS.
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Mioclonia , Humanos , Masculino , Mioclonia/etiologia , Mioclonia/fisiopatologia , Mioclonia/diagnóstico , Mioclonia/tratamento farmacológico , Idoso , Resultado do Tratamento , Músculos Palatinos/fisiopatologia , Síndrome , Infartos do Tronco Encefálico/complicações , Infartos do Tronco Encefálico/diagnóstico por imagem , Infartos do Tronco Encefálico/fisiopatologia , Mesencéfalo/diagnóstico por imagem , Inibidores da Agregação Plaquetária/uso terapêuticoRESUMO
Time-resolved photofluorochromism constitutes a powerful approach to enhance information encryption security but remains challenging. Herein, we report a strategy of using hydrogen bonds to regulate the time for initiating photofluorochromism. In our strategy, copolymers containing negative photochromic spiropyran (NSP), naphthalimide, and multiple hydrogen-bonding (UPy) units are designed, which display photo-switchable fluorescence resonance energy transfer (FRET) process from naphthalimide donor to the NSP acceptor. Interestingly, the FRET is locked via the dynamic hydrogen-bonding interaction between ring-opened NSP and UPy moieties, resulting in time-dependent fluorescence. The change in fluorescence can be finely regulated via UPy fraction in the polymers. Besides the novel time-dependent fluorescence, the polymers also take advantage of visible-light triggerable, excellent photostability, photoreversibility, and processability. We demonstrate that these properties enable them many application opportunities such as fluorescent security labels and multilevel information encryption patterns.
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OBJECTIVE: To analyze and explore the risk factors for neurological symptoms in patients with purely hepatic Wilson's disease (WD) at diagnosis. METHODS: This retrospective study was conducted at the First Affiliated Hospital of the Guangdong Pharmaceutical University on 68 patients with purely hepatic WD aged 20.6 ± 7.2 years. The physical examinations, laboratory tests, color Doppler ultrasound of the liver and spleen, and magnetic resonance imaging (MRI) of the brain were performed. RESULTS: The elevated alanine transaminase (ALT) and aspartate transaminase (AST) levels and 24-h urinary copper level were higher in the purely hepatic WD who developed neurological symptoms (NH-WD) group than those in the purely hepatic WD (H-WD) group. Adherence to low-copper diet, and daily oral doses of penicillamine (PCA) and zinc gluconate (ZG) were lower in the NH-WD group than those in the H-WD group. Logistic regression analysis showed that insufficient doses of PCA and ZG were associated with the development of neurological symptoms in patients with purely hepatic WD at diagnosis. CONCLUSION: The development of neurological symptoms in patients with purely hepatic WD was closely associated with insufficient doses of PCA and ZG, and the inferior efficacy of copper-chelating agents. During the course of anti-copper treatment, the patient's medical status and the efficacy of copper excretion should be closely monitored.
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Degeneração Hepatolenticular , Humanos , Encéfalo , Cobre , Degeneração Hepatolenticular/complicações , Degeneração Hepatolenticular/tratamento farmacológico , Penicilamina/uso terapêutico , Estudos Retrospectivos , Fatores de Risco , Zinco/uso terapêuticoRESUMO
The chemical industry is a significant source of nonmethane volatile organic compounds (NMVOCs), pivotal precursors to ambient ozone (O3), and secondary organic aerosol (SOA). Despite their importance, precise estimation of these emissions remains challenging, impeding the implementation of NMVOC controls. Here, we present the first comprehensive plant-level assessment of NMVOC emissions from the chemical industry in China, encompassing 3461 plants, 127 products, and 50 NMVOC compounds from 2010 to 2019. Our findings revealed that the chemical industry in China emitted a total of 3105 (interquartile range: 1179-8113) Gg of NMVOCs in 2019, with a few specific products accounting for the majority of the emissions. Generally, plants engaged in chemical fibers production or situated in eastern China pose a greater risk to public health due to their higher formation potentials of O3 and SOA or their proximity to residential areas or both. We demonstrated that targeting these high-risk plants for emission reduction could enhance health benefits by 7-37% per unit of emission reduction on average compared to the current situation. Consequently, this study provides essential insights for developing effective plant-specific NMVOC control strategies within China's chemical industry.
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Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Indústria Química , Monitoramento Ambiental , Ozônio/análise , China , Aerossóis/análise , PlantasRESUMO
Poorly cohesive carcinoma not otherwise specified (PCGCA-NOS) is regarded in the most recent WHO classification as a high-grade malignancy; however, some cases may be associated with a relatively good prognosis. We have studied a series of 115 cases of PCGCA-NOS and were able to identify low-grade features in 14 cases based on three morphological manifestations. Immunohistochemical staining, EBER in situ hybridization, Feulgen staining and flow cytometry were employed. Among the 115 cases of PCGAC-NOS, 14 cases met the criteria of "low grade", accounting for 12.2 %. The "low grade" cases exhibited more shallow invasion and less lymph node metastasis (both P < 0.05); showed less frequent expression of MUC5AC, E-cadherin and p53 (all P < 0.05). Moreover, "low grade" PCGAC-NOS had a lower proliferative index(P < 0.001). We also found that the DNA content was lower in the "low grade" group, and aneuploidy was not detected in the "low grade" group, which was sharply different from the control group (50 %). Last, "low grade" PCGAC-NOS had a more favorable prognosis. A small subset of PCGAC-NOS cases have a low grade nature, and the clinicopathological features, immunophenotypes, and cytogenetics of these "low grade" cases differ from those of traditional PCGAC-NOS.
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Adenocarcinoma , Neoplasias Gástricas , Humanos , Adenocarcinoma/patologia , Prognóstico , Hibridização In Situ , Neoplasias Gástricas/patologiaRESUMO
Brain iron is precisely regulated, and disrupted brain iron homeostasis is implicated in neuropsychological disease. Mounting evidence connects the iron status of the substantia nigra (SN) with locomotion-related neural symptomatology. Researchers in this field have long speculated that iron deficiency in the SN directly causes the high-locomotion symptoms observed in neuropsychiatric disorders. However, no direct experimental evidence of a causal relationship has been presented. To explore the relationship between iron deficiency in the SN and locomotion-related phenotypes, we stereotaxically injected the well-documented iron chelator, deferiprone (DFP) into the SN of mice to induce regional brain iron deprivation and subsequently performed behavioral tests. Altered expression of iron metabolism-related molecules was detected in the brain regions with interventions, and behavioral changes were observed. Targeted iron chelation effectively decreased the local iron content of the SN. Among the brain regions examined, only DFP injected into the SN resulted in the hyperlocomotion phenotype. Upon SN iron chelation, transferrin receptor (Tfr) expression was found to be upregulated. Conversely, viral vector-mediated SN-Tfr knockdown was sufficient to induce SN iron deficiency and mimic the hyperlocomotion phenotype. All locomotion changes had a significant negative correlation with iron alteration in the SN. Furthermore, SN iron disturbance also contributed to poor sleep efficiency. Thus, SN iron deficiency directly contributed to triggering both hyperlocomotion and sleep disturbances. This study offers a promising research and therapeutic direction for iron-linked neuropsychiatric diseases.
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Deficiências de Ferro , Animais , Camundongos , Ferro/metabolismo , Quelantes de Ferro/metabolismo , Fenótipo , Substância Negra/metabolismoRESUMO
Solution-processing hybrid solar cells with organics and colloidal quantum dots (CQDs) have drawn substantial attention in the past decade. Nevertheless, hybrid solar cells based on the recently developed directly synthesized CQD inks are still unexplored. Herein, a facile polymer blending strategy is put forward to enable directly synthesized CQD/polymer hybrid solar cells with a champion efficiency of 13%, taking advantage of the conjugated polymer blends with finely optimized aggregation behaviors. The spectroscopic and electrical investigations on carrier transport and recombination indicate that polymer blends can endow fast carrier transport and less recombination over the single counterparts. Moreover, the blending strategy offers a "dilution effect" for top-notch photovoltaic polymers with excessively strong aggregation tendency, resulting in moderate feature domain size and surface roughness, which afford fast hole transport and therefore high photovoltaic performance. The effectiveness of this strategy is successfully validated using two pairs of photovoltaic polymers. Accordingly, the relationships between polymer morphology, carrier transport, and photovoltaic performance are established to advance the progress of CQD/polymer hybrid solar cells. Such progress stresses that the utilization of aggregation-suppressed polymer blends is a facile approach toward the fabrication of high-efficiency organic-inorganic hybrid solar cells.
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The physical layer security of millimeter-wave radio-over-fiber (MMW-RoF) system at W-band is a promising topic. This paper experimentally demonstrates a one-time pad scheme based on polar code and orthogonal frequency division multiplexing (OFDM) for MMW-RoF system. In the proposed scheme, the initial key is obtained by looking-up table mapping randomly, and chaotic sequence is generated by using 4-D cellular neural network (CNN). The key for next frame is placed in the partial frozen bits of polar code, which can realize the one-time pad mechanism. The encrypted OFDM signal carried by 100GHz millimeter-wave is successfully transmitted over 50 km standard single-mode fiber (SSMF) and 5 m wireless channel in this experiment. The experimental results show that, compared with the traditional OFDM signal, the proposed scheme in SCL8 decoder can achieve â¼4.1 dB gain at the BER of 10-3, which can effectively use the frozen bits of polar code to transmit more information and improve the security and reliability of the whole system.
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BACKGROUND: Recent studies have shown that chronic kidney disease (CKD) prevalence is significantly higher in patients with hepatic steatosis (HS); however, it remains unclear whether HS is associated with serum creatinine (SCr). We aimed to explore the association between SCr levels and HS in a Chinese population. METHODS: We performed a cross-sectional study among 56,569 Chinese individuals. SCr level, other clinical and laboratory parameters, abdominal ultrasound and noninvasive fibrosis scores were extracted, and the fibrosis 4 score (FIB-4) was calculated. RESULTS: A total of 27.1% of the subjects had HS. After 1:1 propensity score matching (PSM) according to sex and age, we included 13,301 subjects with HS and 13,301 subjects without HS. SCr levels were significantly higher in the HS group than in the non-HS group [73.19 ± 15.14(µmoI/L) vs. 71.75 ± 17.49(µmoI/L), p < 0.001]. Univariate and multivariate regression analyses showed a positive association between SCr and the prevalence of HS. Stepwise regression analysis showed that the association between SCr and HS was independent of other metabolic syndrome components. The prevalence of HS increased significantly with increasing SCr levels. Metabolism-related indicators and liver enzymes were significantly higher in the HS group than in the non-HS group; furthermore, these parameters increased with increasing SCr levels. FIB-4 was significantly higher in the HS group than in the non-HS group but did not show an increasing trend with increasing SCr levels. CONCLUSIONS: Our results showed an independent association between SCr level and HS risk in a Chinese population.
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Fígado Gorduroso , Síndrome Metabólica , Creatinina , Estudos Transversais , Fígado Gorduroso/complicações , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/epidemiologia , Síndrome Metabólica/complicaçõesRESUMO
A 4D 8-pulse amplitude modulation trellis-coded modulation-based orthogonal frequency division multiplexing (4D 8PAM TCM-OFDM) scheme combined with discrete Fourier transform (DFT) precoding is proposed and experimentally demonstrated in an underwater optical wireless communications system. It can resist power fading caused by the attenuation, scattering, and reflection in the water channel. The experimental results show that, after transmission over the water-air channel and at the bit error rate of 3.8×10-3, the improvement in the receiver sensitivity is 0.88 dB using the 4D 8PAM TCM-OFDM scheme, compared to the conventional 64QAM-OFDM scheme. In addition, the proposed 4D 8PAM TCM-OFDM scheme combined with DFT precoding can compensate for unbalanced impairments, and it can obtain 1.28 dB receiver sensitivity improvement, compared to the conventional 64QAM-OFDM scheme with DFT precoding.
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The aim of this study was to establish a practical approach to remove ammonium nitrogen of rare earth elements (REEs) wastewater by an indigenous photoautotrophic microalga. Firstly, a new microalgal strain was successfully isolated from REEs wastewater and identified as Chlamydomonas sp. (named Chlamydomonas sp. YC). The obtained results showed that microalga could completely remove the NH4+-N of 10% REEs wastewater after 10 days of cultivation; however, the highest NH4+-N removal rate was attained by microalga to treat undiluted REEs wastewater. Then, three cultivation modes including batch, semi-continuous and continuous cultivation methods were developed to evaluate the ability of NH4+-N removal rate by this microalga to treat diluted (10%) and undiluted REEs wastewater. It was found that, Chlamydomonas sp. YC exhibited superior performance towards NH4+-N removal rates (32.75-61.05 mg/(L·d)) by semi-continuous and continuous processes for the treatments of 10% and undiluted REEs wastewater in comparison to the results (19.50-30.38 mg/(L·d) by batch process. Interestingly, under the same treatment conditions, among the three cultivation modes, microalga exhibited the highest removal rates of NH4+-N in undiluted REEs wastewater by semi-continuous (61.05 mg/(L·d)) and continuous (57.10 mg/(L·d) processes. In term of the biochemical analysis, microalgal biomass obtained from the wastewater treatment had 35.40-44.40% carbohydrate and 4.97-6.03% lipid, which could be potential ingredients for sustainable biofuels production. And the highest carbohydrate and lipid productivities attained by Chlamydomonas sp. YC in the continuous mode were 226.36 mg/(L·d) and 32.98 mg/(L·d), respectively. Taken together, the established processes mediated with Chlamydomonas sp. YC via continuous cultivation was the great promising approaches to efficiently remove NH4+-N of REEs wastewater and produce valuable biomass for sustainable and renewable biofuels in a simultaneous manner.
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Compostos de Amônio , Chlamydomonas , Metais Terras Raras , Microalgas , Biocombustíveis , Biomassa , Carboidratos , Lipídeos , Nitrogênio , Águas ResiduáriasRESUMO
The Chinese medicinal plant Panax notoginseng has been traditionally used to activate blood flow and circulation, and to prevent blood stasis. P. notoginseng contains protopanaxatriol (PPT)-type saponins as its main active compounds, thus distinguishing it from the other two famous Panax species, P. ginseng and P. quinquefolius. Ginsenoside Rg1 (Rg1), notoginsenoside R1 (NgR1), and notoginsenoside R2 (NgR2) are three major PPT-type saponins in P. notoginseng and possess potential cardiovascular protection activities. However, their use in medical applications has long been hampered by the lack of sustainable and low-cost industrial-scale preparation methods. In this study, a PPT-producing yeast chassis strain was designed and constructed based on a previously constructed and optimized protopanaxadiol (PPD)-producing Saccharomyces cerevisiae strain, and further optimized by systemically engineering and optimizing the expression level of its key P450 biopart. Rg1-producing yeast strains were constructed by introducing PgUGT71A53 and PgUGT71A54 into the PPT chassis strain. The fermentation titer of Rg1 reached 1.95 g/L. A group of UDP-glycosyltransferases (UGT) from P. notoginseng and P. ginseng were characterized, and were found to generate NgR1 and NgR2 by catalyzing the C6-O-Glc xylosylation of Rg1 and Rh1, respectively. Using one of these UGTs, PgUGT94Q13, and the previously identified PgUGT71A53 and PgUGT71A54, the biosynthetic pathway to produce saponins NgR1 and NgR2 from PPT could be available. The NgR1 cell factory was further developed by introducing PgUGT94Q13 and a heterologous UDP-xylose biosynthetic pathway from Arabidopsis thaliana into the highest Rg1-producing cell factory. The NgR2-producing cell factory was constructed by introducing PgUGT71A54, PgUGT94Q13, and the UDP-xylose biosynthetic pathway into the PPT chassis. De novo production of NgR1 and NgR2 reached 1.62 g/L and 1.25 g/L, respectively. Beyond the realization of artificial production of the three valuable saponins Rg1, NgR1, and NgR2 from glucose, our work provides a green and sustainable platform for the efficient production of other PPT-type saponins in engineered yeast strains, and promotes the industrial application of PPT-type saponins as medicine and functional foods.
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Ginsenosídeos , Panax notoginseng , Panax , Saponinas , Glicosiltransferases/genética , Panax/genética , Panax notoginseng/genética , Saccharomyces cerevisiae/genética , SapogeninasRESUMO
The physical layer security of radio-over-fiber (RoF) system is a very important problem for future communication. In this paper, a novel probabilistic shaping (PS) based constellation encryption scheme is proposed in which two bit-level encryption operations are firstly performed according to chaotic sequences and hash values. The chaotic sequences are generated by hyperchaotic system and hash values are obtained by SHA-512. Then PS is applied to enhance transmission performance. After PS-16-quadrature amplitude modulation (QAM), constellation encryption is implemented aiming at maintaining overall shaping distribution unchanged and improving security. An encrypted PS-16-QAM orthogonal frequency division multiplexing (OFDM) signal is successfully transmitted over 50 km standard single-mode fiber (SSMF) and 5 m wireless channel in our experiment. The results demonstrate that the key space of 10121 is achieved to defend malicious attacks. Moreover, the proposed PS-based encryption scheme can obtain approximately 2.4 dB gain at a BER of 10-3 compared with traditional OFDM signal. Thus, the proposed scheme has a good application prospect in the future OFDM-RoF system due to the dominant BER and security performance.
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Current neural networks are mostly built on the MP model, which usually formulates the neuron as executing an activation function on the real-valued weighted aggregation of signals received from other neurons. This letter proposes the flexible transmitter (FT) model, a novel bio-plausible neuron model with flexible synaptic plasticity. The FT model employs a pair of parameters to model the neurotransmitters between neurons and puts up a neuron-exclusive variable to record the regulated neurotrophin density. Thus, the FT model can be formulated as a two-variable, two-valued function, taking the commonly used MP neuron model as its particular case. This modeling manner makes the FT model biologically more realistic and capable of handling complicated data, even spatiotemporal data. To exhibit its power and potential, we present the flexible transmitter network (FTNet), which is built on the most common fully connected feedforward architecture taking the FT model as the basic building block. FTNet allows gradient calculation and can be implemented by an improved backpropagation algorithm in the complex-valued domain. Experiments on a broad range of tasks show that FTNet has power and potential in processing spatiotemporal data. This study provides an alternative basic building block in neural networks and exhibits the feasibility of developing artificial neural networks with neuronal plasticity.
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Tungsten disulfide (WS2) nanosheets (NSs) have become a promising room-temperature gas sensor candidate due to their inherent high surface-to-volume ratio, tunable electrical properties, and high on-state current density. For further practical applications of WS2-based gas sensors, it is still necessary to overcome the insensitive response and incomplete recovery at room temperature. In this work, we controllably synthesized high-performance ammonia (NH3) gas sensor based on CuO decorated WS2NSs. The optimized p-p WS2/CuO heterojunctions improve the surface catalytic effect, thereby enhancing the gas-sensing performance. The pure WS2NSs-based gas sensors showed a low response and an incomplete recovery in the case of NH3sensing. After the functionalization of CuO nanoparticles, the WS2/CuO heterostructure-based gas sensor exhibits an improved response value of 40.5% to 5⯠ppm NH3and full recoverability without any external assistance. Density functional theory calculations illustrate that the adsorption of CuO for NH3is much superior to WS2. The p-p heterojunctions strategy demonstrated in this work has great potential in the design of sensitive materials for gas sensors, and provides useful guidance for enhancing the room-temperature sensitivity and recoverability.
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BACKGROUND: Aberrant activation of Wnt/ß-catenin signaling by dysregulated post-translational protein modifications, especially ubiquitination is causally linked to cancer development and progression. Although Lys48-linked ubiquitination is known to regulate Wnt/ß-catenin signaling, it remains largely obscure how other types of ubiquitination, such as linear ubiquitination governs its signaling activity. METHODS: The expression and regulatory mechanism of linear ubiquitin chain assembly complex (LUBAC) on Wnt/ß-catenin signaling was examined by immunoprecipitation, western blot and immunohistochemical staining. The ubiquitination status of ß-catenin was detected by ubiquitination assay. The impacts of SHARPIN, a core component of LUBAC on malignant behaviors of gastric cancer cells were determined by various functional assays in vitro and in vivo. RESULTS: Unlike a canonical role in promoting linear ubiquitination, SHARPIN specifically interacts with ß-catenin to maintain its protein stability. Mechanistically, SHARPIN competes with the E3 ubiquitin ligase ß-Trcp1 for ß-catenin binding, thereby decreasing ß-catenin ubiquitination levels to abolish its proteasomal degradation. Importantly, SHARPIN is required for invasiveness and malignant growth of gastric cancer cells in vitro and in vivo, a function that is largely dependent on its binding partner ß-catenin. In line with these findings, elevated expression of SHARPIN in gastric cancer tissues is associated with disease malignancy and correlates with ß-catenin expression levels. CONCLUSIONS: Our findings reveal a novel molecular link connecting linear ubiquitination machinery and Wnt/ß-catenin signaling via SHARPIN-mediated stabilization of ß-catenin. Targeting the linear ubiquitination-independent function of SHARPIN could be exploited to inhibit the hyperactive ß-catenin signaling in a subset of human gastric cancers.
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Carcinogênese/genética , Neoplasias Gástricas/genética , Ubiquitinação/genética , Ubiquitinas/genética , beta Catenina/genética , Humanos , Via de Sinalização Wnt/genéticaRESUMO
Two-dimensional (2D) layered nanomaterials have attracted increasing attention in gas sensing due to their graphene-like properties. Although the gas sensing performances of 2D layered semiconductor transition metal dichalcogenides (TMDs), including MoS2, WS2, MoSe2 and WSe2, have been extensively studied, it has remained a grand challenge to develop a high-performance gas sensing material that can meet practical applications. Tantalum disulfide (TaS2), as a metallic TMD with low resistance and high current signal, has great promise in high-performance gas sensing. In stark contrast with Mo and W, Ta has a stronger positive charge, which contributes to a higher surface energy to capture gas molecules. Herein, through calculating the adsorption energy, charge transfer, electronic structure, and work function of the adsorption system with first-principles calculations, we first systematically studied the performance of noble metal atom substitution doping on a TaS2 monolayer for toxic nitrogen-containing gas (NH3, NO and NO2) sensing. We found that the TaS2 monolayer exhibits excellent NO sensing performance with an adsorption energy of 0.49 eV and a charge transfer of 0.17 e. However, it has a considerable adsorption energy (-0.22 and -0.39 eV) to NH3 and NO2 molecules, but a low charge transfer (-0.03 and 0.04 e) between the gas molecules and the TaS2 monolayer. To further enhance the gas-sensing performance of the TaS2 monolayer, noble metal atoms (Ag, Au, Pd and Pt) were substitutionally doped into the lattice of the TaS2 monolayer. The results showed that the values of adsorption energy and charge transfer can be significantly improved, and the electronic structure and work function of the doping system has also greatly changed, which makes it much easier to detect the changes in electrical signal due to gas adsorption. Our work indicates that the intrinsic as well as the noble metal doped TaS2 monolayers are promising candidates for high-performance gas sensors.