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Cyclic-di-GMP (c-di-GMP) is a ubiquitous bacterial signaling molecule. It is also a critical player in the regulation of cell size and cell behaviors such as cell aggregation and phototaxis in cyanobacteria, which constitute an important group of prokaryotes for their roles in the ecology and evolution of the Earth. However, c-di-GMP receptors have never been revealed in cyanobacteria. Here, we report the identification of a c-di-GMP receptor, CdgR, from the filamentous cyanobacterium Anabaena PCC 7120. Crystal structural analysis and genetic studies demonstrate that CdgR binds c-di-GMP at the dimer interface and this binding is required for the control of cell size in a c-di-GMP-dependent manner. Different functions of CdgR, in ligand binding and signal transmission, could be separated genetically, allowing us to dissect its molecular signaling functions. The presence of the apo-form of CdgR triggers cell size reduction, consistent with the similar effects observed with a decrease of c-di-GMP levels in cells. Furthermore, we found that CdgR exerts its function by interacting with a global transcription factor DevH, and this interaction was inhibited by c-di-GMP. The lethal effect triggered by conditional depletion of DevH or by the production of several point-mutant proteins of CdgR in cells indicates that this signaling pathway plays critical functions in Anabaena. Our studies revealed a mechanism of c-di-GMP signaling in the control of cell size, an important and complex trait for bacteria. CdgR is highly conserved in cyanobacteria, which will greatly expand our understanding of the roles of c-di-GMP signaling in these organisms.
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Cianobactérias , Transdução de Sinais , Cianobactérias/metabolismo , GMP Cíclico/metabolismo , Regulação da Expressão Gênica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão GênicaRESUMO
Water-logged peatlands store tremendous amounts of soil carbon (C) globally, accumulating C over millennia. As peatlands become disturbed by human activity, these long-term C stores are getting destabilized and ultimately released as greenhouse gases that may exacerbate climate change. Oxidation of the dissolved organic carbon (DOC) mobilized from disturbed soils to streams and canals may be one avenue for the transfer of previously stored, millennia-aged C to the atmosphere. However, it remains unknown whether aged peat-derived DOC undergoes oxidation to carbon dioxide (CO2) following disturbance. Here, we use a new approach to measure the radiocarbon content of CO2 produced from the oxidation of DOC in canals overlying peatland soils that have undergone widespread disturbance in Indonesia. This work shows for the first time that aged DOC mobilized from drained and burned peatland soils is susceptible to oxidation by both microbial respiration and photomineralization over aquatic travel times for DOC. The bulk radiocarbon age of CO2 produced during canal oxidation ranged from modern to ~1300 years before present. These ages for CO2 were most strongly influenced by canal water depth, which was proportional to the water table level where DOC is mobilized from disturbed soils to canals. Canal microbes preferentially respired older or younger organic C pools to CO2, and this may have been facilitated by the use of a small particulate organic C pool over the dissolved pool. Given that high densities of canals are generally associated with lower water tables and higher fire risk, our findings suggest that peatland areas with high canal density may be a hotspot for the loss of aged C on the landscape. Taken together, the results of this study show how and why aquatic processing of organic C on the landscape can enhance the transfer of long-term peat C stores to the atmosphere following disturbance.
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Dióxido de Carbono , Carbono , Solo , Solo/química , Dióxido de Carbono/análise , Carbono/análise , Indonésia , OxirreduçãoRESUMO
Bone defects are characterized by a hypoxic environment, which affects bone tissue repair. However, the role of hypoxia in the repair of alveolar bone defects remains unclear. Human periodontal ligament stem cells (hPDLSCs) are high-quality seed cells for repairing alveolar bone defects, whose behavior changes under hypoxia. However, their mechanism of action is not known and needs to be elucidated. We hypothesized that hypoxia might be beneficial to alveolar bone defect repair and the osteogenic differentiation of hPDLSCs. To test this hypothesis, cobalt chloride (CoCl2) was used to create a hypoxic environment, both in vitro and in vivo. In vitro study, the best osteogenic effect was observed after 48 h of hypoxia in hPDLSCs, and the AKT/mammalian target of rapamycin/eukaryotic translation initiation factor 4e-binding protein 1 (AKT/mTOR/4EBP-1) signaling pathway was significantly upregulated. Inhibition of the AKT/mTOR/4EBP-1 signaling pathway decreased the osteogenic ability of hPDLSCs under hypoxia and hypoxia-inducible factor 1 alpha (HIF-1α) expression. The inhibition of HIF-1α also decreased the osteogenic capacity of hPDLSCs under hypoxia without significantly affecting the level of phosphorylation of AKT/mTOR/4EBP-1. In vitro study, Micro-CT and tissue staining results show better bone regeneration in hypoxic group than control group. These results suggested that hypoxia promoted alveolar bone defect repair and osteogenic differentiation of hPDLSCs, probably through AKT/mTOR/4EBP-1/HIF-1α signaling. These findings provided important insights into the regulatory mechanism of hypoxia in hPDLSCs and elucidated the effect of hypoxia on the healing of alveolar bone defects. This study highlighted the importance of physiological oxygen conditions for tissue engineering.
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Perda do Osso Alveolar , Diferenciação Celular , Hipóxia Celular , Cobalto , Subunidade alfa do Fator 1 Induzível por Hipóxia , Osteogênese , Ligamento Periodontal , Humanos , Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Perda do Osso Alveolar/metabolismo , Regeneração Óssea/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Cobalto/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Osteogênese/efeitos dos fármacos , Ligamento Periodontal/metabolismo , Ligamento Periodontal/citologia , Fosfoproteínas/metabolismo , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células-Tronco/metabolismo , Serina-Treonina Quinases TOR/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismoRESUMO
AIMS: To reveal the inhibition mechanism of rose, mustard, and blended essential oils against Cladosporium allicinum isolated from Xinjiang naan, and investigate the effect of the three essential oils on oxidative damage and energy metabolism. METHODS AND RESULTS: Rose and mustard essential oils significantly inhibited mycelial growth and spore viability in a dose-dependent relationship. After essential oil treatment, the cell membrane permeability was altered, and significant leakage of intracellular proteins and nucleic acids occurred. SEM observations further confirmed the disruption of cell structure. ROS, MDA, and SOD measurements indicated that essential oil treatment induced a redox imbalance in C. allicinum, leading to cell death. As for energy metabolism, essential oil treatment significantly reduced Na+K+-ATPase, Ca2+Mg2+-ATPase, MDH activity, and CA content, impairing metabolic functions. Finally, storage experiments showed that all three essential oils ensured better preservation of naan, with mustard essential oil having the best antifungal effect. CONCLUSIONS: Rose and mustard essential oils and their blends can inhibit C. allicinum at multiple targets and pathways, destroying cell morphological structure and disrupting metabolic processes.
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Cladosporium , Óleos Voláteis , Rosa , Óleos Voláteis/farmacologia , Antifúngicos/farmacologia , Mostardeira , Óleos de Plantas/farmacologiaRESUMO
BACKGROUND: Numerous studies have investigated the mean arterial pressure in patients with sepsis, and many meaningful results have been obtained. However, few studies have measured the systolic blood pressure (SBP) multiple times and established trajectory models for patients with sepsis with different SBP trajectories. METHODS: Data from patients with sepsis were extracted from the Medical Information Mart for Intensive Care-III database for inclusion in a retrospective cohort study. Ten SBP values within 10 h after hospitalization were extracted, and the interval between each SBP value was 1 h. The SBP measured ten times after admission was analyzed using latent growth mixture modeling to construct a trajectory model. The outcome was in-hospital mortality. The survival probability of different trajectory groups was investigated using Kaplan-Meier (K-M) analysis, and the relationship between different SBP trajectories and in-hospital mortality risk was investigated using Cox proportional-hazards regression model. RESULTS: This study included 3034 patients with sepsis. The median survival time was 67 years (interquartile range: 56-77 years). Seven different SBP trajectories were identified based on model-fit criteria. The in-hospital mortality rates of the patients in trajectory classes 1-7 were 25.5%, 40.5%, 11.8%, 18.3%, 23.5%, 13.8%, and 10.5%, respectively. The K-M analysis indicated that patients in class 2 had the lowest probability of survival. Univariate and multivariate Cox regression analysis indicated that, with class 1 as a reference, patients in class 2 had the highest in-hospital mortality risk (P < 0.001). Subgroup analysis indicated that a nominal interaction occurred between age group and blood pressure trajectory in the in-hospital mortality (P < 0.05). CONCLUSION: Maintaining a systolic blood pressure of approximately 140 mmHg in patients with sepsis within 10 h of admission was associated with a lower risk of in-hospital mortality. Analyzing data from multiple measurements and identifying different categories of patient populations with sepsis will help identify the risks among these categories.
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Sepse , Humanos , Pressão Sanguínea/fisiologia , Mortalidade Hospitalar , Estudos Retrospectivos , Modelos de Riscos ProporcionaisRESUMO
OBJECTIVE: To understand the facial emotion recognition of male veterans with chronic schizophrenia and the relationship between facial emotion recognition and interpersonal communication to provide a reference for designing social skills training programmes. METHOD: Fifty-six eligible male patients with chronic schizophrenia who were admitted to our hospital from October 2020 to April 2021 were selected, and 24 healthy people were selected as controls. Facial emotion recognition, social communication skills and self-perceived interpersonal disturbance were assessed using a facial emotion recognition stimulus manual, the Social Skills Checklist (SSC) and the Interpersonal Relationship Integrative Diagnostic Scale (IRIDS). Disease status was assessed using the Positive and Negative Syndrome Scale. RESULTS: Both the control group and the patient group had the highest recognition accuracy for neutral faces. The recognition rate for neutral expression was higher in the control group than in the patient group (p = 0.008). The rate of neutral expressions identified as happiness was higher in the patient group than in the control group (p = 0.001). The identification of anger as happiness was higher in the control group than in the patient group (p = 0.026), and the pattern of misidentification was similar between the control group and the patient group. The accuracy of facial emotion recognition was negatively associated with the age of onset (p < 0.05). The recognition accuracy for happiness was negatively associated with negative symptoms, general pathological symptoms and total scale scores (p < 0.05). The total score for expression recognition was negatively associated with the negative symptom subscale scores (p < 0.05), and there was no correlation between expression recognition and positive symptoms (p > 0.05). The recognition accuracy for happiness was negatively correlated with the IRIDS conversation factor (p < 0.05). The recognition accuracy for happiness and anger and the total scores for facial emotion recognition were negatively correlated with the SSC subscale score and the total score (p < 0.05 and p < 0.01, respectively). The main influencing factors on facial emotion recognition were the SSC total score (p < 0.001) and the positive factor score (p = 0.039). CONCLUSION: Veterans with chronic schizophrenia have facial emotion recognition impairments affected by negative symptoms. There is a correlation between facial emotion recognition and interpersonal communication. HIGHLIGHTS: 1. There are extensive facial expression recognition disorders in schizophrenia. 2. The pattern of misidentification was similar in both the control group and the patient group, with the tendency for happiness to be identified as a neutral emotion, anger as happiness, and fear as neutral emotion and anger. 3. Based on the comprehensive assessment of social cognitive impairment in patients with schizophrenia, prospective studies of standardised interventions are designed to provide support for clinical practice.
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Reconhecimento Facial , Esquizofrenia , Veteranos , Humanos , Masculino , Esquizofrenia/diagnóstico , Estudos de Casos e Controles , Estudos Retrospectivos , Estudos Prospectivos , Emoções , Felicidade , Comunicação , Expressão FacialRESUMO
BACKGROUND: This study aimed to construct a risk prediction model to estimate the odds of osteoporosis (OP) in elderly patients with type 2 diabetes mellitus (T2DM) and evaluate its prediction efficiency. METHODS: This study included 21,070 elderly patients with T2DM who were hospitalized at six tertiary hospitals in Southwest China between 2012 and 2022. Univariate logistic regression analysis was used to screen for potential influencing factors of OP and least absolute shrinkage. Further, selection operator regression (LASSO) and multivariate logistic regression analyses were performed to select variables for developing a novel predictive model. The area under the receiver operating characteristic curve (AUROC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) were used to evaluate the performance and clinical utility of the model. RESULTS: The incidence of OP in elderly patients with T2DM was 7.01% (1,476/21,070). Age, sex, hypertension, coronary heart disease, cerebral infarction, hyperlipidemia, and surgical history were the influencing factors. The seven-variable model displayed an AUROC of 0.713 (95% confidence interval [CI]:0.697-0.730) in the training set, 0.716 (95% CI: 0.691-0.740) in the internal validation set, and 0.694 (95% CI: 0.653-0.735) in the external validation set. The optimal decision probability cut-off value was 0.075. The calibration curve (bootstrap = 1,000) showed good calibration. In addition, the DCA and CIC demonstrated good clinical practicality. An operating interface on a webpage ( https://juntaotan.shinyapps.io/osteoporosis/ ) was developed to provide convenient access for users. CONCLUSIONS: This study constructed a highly accurate model to predict OP in elderly patients with T2DM. This model incorporates demographic characteristics and clinical risk factors and may be easily used to facilitate individualized prediction.
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Diabetes Mellitus Tipo 2 , Osteoporose , Idoso , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiologia , Estudos Retrospectivos , Osteoporose/diagnóstico , Osteoporose/epidemiologia , Fatores de Risco , Infarto CerebralRESUMO
We report national scale estimates of CO2 emissions from fossil-fuel combustion and cement production in the United States based directly on atmospheric observations, using a dual-tracer inverse modeling framework and CO2 and [Formula: see text] measurements obtained primarily from the North American portion of the National Oceanic and Atmospheric Administration's Global Greenhouse Gas Reference Network. The derived US national total for 2010 is 1,653 ± 30 TgC yr-1 with an uncertainty ([Formula: see text]) that takes into account random errors associated with atmospheric transport, atmospheric measurements, and specified prior CO2 and 14C fluxes. The atmosphere-derived estimate is significantly larger ([Formula: see text]) than US national emissions for 2010 from three global inventories widely used for CO2 accounting, even after adjustments for emissions that might be sensed by the atmospheric network, but which are not included in inventory totals. It is also larger ([Formula: see text]) than a similarly adjusted total from the US Environmental Protection Agency (EPA), but overlaps EPA's reported upper 95% confidence limit. In contrast, the atmosphere-derived estimate is within [Formula: see text] of the adjusted 2010 annual total and nine of 12 adjusted monthly totals aggregated from the latest version of the high-resolution, US-specific "Vulcan" emission data product. Derived emissions appear to be robust to a range of assumed prior emissions and other parameters of the inversion framework. While we cannot rule out a possible bias from assumed prior Net Ecosystem Exchange over North America, we show that this can be overcome with additional [Formula: see text] measurements. These results indicate the strong potential for quantification of US emissions and their multiyear trends from atmospheric observations.
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Whether spermine promotes the repair of porcine intestinal epithelium damage through Ras-related C3 botulinum toxin substrate 1 (Rac1)/phospholipase C-γ1 (PLC-γ1) signaling remains unclear. The current study investigated the effects of spermine addition on the proliferation and migration of IPEC-J2 cells and the effects of Rac1/PLC-γ1 signaling on cell migration. We showed that the inhibitors of Rac1 (NSC-23766) and PLC-γ1 (U73122) reduced cell migration and decreased the protein levels of Rac1 and PLC-γ1 in the cells. Moreover, spermine promoted the proliferation and migration of the IPEC-J2 cells, that is, 1 µM spermine exhibited the best effect, and spermine treatment increased the protein levels of Rac1 and PLC-γ1. Further experiments showed that spermine treatment increased cell migration and enhanced Rac1 and PLC-γ1 protein levels, compared with NSC-23766 and U73122 treatments with spermine. In conclusion, spermine treatment promoted the repair of damaged porcine intestinal epithelium by accelerating cell proliferation and migration mediated by Rac1/PLC-γ1 signaling.
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Mucosa Intestinal , Espermina , Animais , Suínos , Espermina/metabolismo , Espermina/farmacologia , Movimento Celular , Proliferação de Células , Células Epiteliais/metabolismoRESUMO
BACKGROUND: Pine wilt disease (PWD) is a destructive disease that endangers pine trees, resulting in the wilting, with yellowing and browning of the needles, and eventually the death of the trees. Previous studies showed that the Avr9/Cf-9 rapidly elicited (PmACRE1) gene was downregulated by Bursaphelenchus xylophilus infection, suggesting a correlation between PmACRE1 expression and pine tolerance. Here, we used the expression of PmACRE1 in Arabidopsis thaliana to evaluate the role of PmACRE1 in the regulation of host defence against B. xylophilus infection. RESULTS: Our results showed that the transformation of PmACRE1 into A. thaliana enhanced plant resistance to the pine wood nematode (PWN); that is, the leaves of the transgenic line remained healthy for a longer period than those of the blank vector group. Ascorbate peroxidase (APX) activity and total phenolic acid and total flavonoid contents were higher in the transgenic line than in the control line. Widely targeted metabolomics analysis of the global secondary metabolites in the transgenic line and the vector control line showed that the contents of 30 compounds were significantly different between these two lines; specifically, the levels of crotaline, neohesperidin, nobiletin, vestitol, and 11 other compounds were significantly increased in the transgenic line. The studies also showed that the ACRE1 protein interacted with serine hydroxymethyltransferase, catalase domain-containing protein, myrosinase, dihydrolipoyl dehydrogenase, ketol-acid reductoisomerase, geranylgeranyl diphosphate reductase, S-adenosylmethionine synthase, glutamine synthetase, and others to comprehensively regulate plant resistance. CONCLUSIONS: Taken together, these results indicate that PmACRE1 has a potential role in the regulation of plant defence against PWNs.
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Arabidopsis , Pinus , Arabidopsis/genética , Xylophilus , Folhas de Planta , Glicina Hidroximetiltransferase , Glutamato-Amônia LigaseRESUMO
The genetically regulated pattern of heterocyst formation in multicellular cyanobacteria represents the simplest model to address how patterns emerge and are established, the signals that control them, and the regulatory pathways that act downstream. Although numerous factors involved in this process have been identified, the mechanisms of action of many of them remain largely unknown. The aim of this study was to identify specific relationships between 14 factors required for cell differentiation and pattern formation by exploring their putative physical interactions in the cyanobacterium model Nostoc sp. PCC 7120 and by probing their evolutionary conservation and distribution across the cyanobacterial phylum. A bacterial two-hybrid assay indicated that 10 of the 14 factors studied here are engaged in more than one protein-protein interaction. The transcriptional regulator PatB was central in this network as it showed the highest number of binary interactions. A phylum-wide genomic survey of the distribution of these factors in cyanobacteria showed that they are all highly conserved in the genomes of heterocyst-forming strains, with the PatN protein being almost restricted to this clade. Interestingly, eight of the factors that were shown to be capable of protein interactions were identified as key elements in the evolutionary genomics analysis. These data suggest that a network of 12 proteins may play a crucial role in heterocyst development and patterning. Unraveling the physical and functional interactions between these factors during heterocyst development will certainly shed light on the mechanisms underlying pattern establishment in cyanobacteria.
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Regulação Bacteriana da Expressão Gênica , Nostoc , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Genômica , Nostoc/genética , Nostoc/metabolismoRESUMO
The aim of the study was to examine the correlation between COVID-19 vaccine coverage rates and outcomes of the COVID-19 epidemic in the case of COVID-19 variants based on real-world data. The data came from Our World in Data, which is building the international COVID-19 vaccination data set and is an open-source data set for everyone to use. The vaccination data set uses the most recent official numbers from governments and health ministries worldwide. We assessed the correlation between COVID-19 vaccine coverage rates and outcomes of the COVID-19 epidemic with existing variants by performing temporal analysis and spatial analysis. Overall, new cases per million population, the reproduction rate of COVID-19, new deaths from all causes per million population, excess mortality attributed to COVID-19 pandemic, and hospital patients or intensive care unit (ICU) patients per million population were not decreased with the time course. However, at the same time point, new cases per million population, the reproduction rate of COVID-19, new deaths per million population, and hospital patients or ICU patients per million population gradually decreased as the rate of vaccination coverage increased. High coverage percentages of COVID-19 vaccination were negatively correlated with the reproduction rate of COVID-19 (correlation coefficient -0.116) and ICU patients per million of the local population (correlation coefficient -0.055). Currently, there is no effective treatment for the COVID-19 pandemic, and prevention of the COVID-19 pandemic mainly depends on vaccines, especially when the rate of COVID-19 vaccine coverage is over 60%. The benefits of preventing severe disease and preventing transmission of infection are likely to be obvious.
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COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos , Pandemias , SARS-CoV-2 , VacinaçãoRESUMO
Carbon- and nitrogen-containing aerosols are ubiquitous in urban atmospheres and play important roles in air quality and climate change. We determined the 14C fraction modern (fM) and δ13C of total carbon (TC) and δ15N of NH4+ in the PM2.5 collected in Seoul megacity during April 2018 to December 2019. The seasonal mean δ13C values were similar to -25.1 ± 2.0 in warm and -24.2 ± 0.82 in cold seasons. Mean δ15N values were higher in warm (16.4 ± 2.8) than in cold seasons (4.0 ± 6.1), highlighting the temperature effects on atmospheric NH3 levels and phase-equilibrium isotopic exchange during the conversion of NH3 to NH4+. While 37% ± 10% of TC was apportioned to fossil-fuel sources on the basis of fM values, δ15N indicated a higher contribution of emissions from vehicle exhausts and electricity generating units (power-plant NH3 slip) to NH3: 60% ± 26% in warm season and 66% ± 22% in cold season, based on a Bayesian isotope-mixing model. The collective evidence of multiple isotope analysis reasonably supports the major contribution of fossil-fuel-combustion sources to NH4+, in conjunction with TC, and an increased contribution from vehicle emissions during the severe PM2.5 pollution episodes. These findings demonstrate the efficacy of a multiple-isotope approach in providing better insight into the major sources of PM2.5 in the urban atmosphere.
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Poluentes Atmosféricos , Compostos de Amônio , Aerossóis/análise , Poluentes Atmosféricos/análise , Teorema de Bayes , Carbono/análise , China , Monitoramento Ambiental , Combustíveis Fósseis/análise , Isótopos , Material Particulado/análise , Estações do Ano , Seul , Emissões de Veículos/análiseRESUMO
BACKGROUND: Glioma is the most common brain malignant tumor, with a high morbidity rate and a mortality rate of more than three percent, which seriously endangers human health. The main method of acquiring brain tumors in the clinic is MRI. Segmentation of brain tumor regions from multi-modal MRI scan images is helpful for treatment inspection, post-diagnosis monitoring, and effect evaluation of patients. However, the common operation in clinical brain tumor segmentation is still manual segmentation, lead to its time-consuming and large performance difference between different operators, a consistent and accurate automatic segmentation method is urgently needed. With the continuous development of deep learning, researchers have designed many automatic segmentation algorithms; however, there are still some problems: (1) The research of segmentation algorithm mostly stays on the 2D plane, this will reduce the accuracy of 3D image feature extraction to a certain extent. (2) MRI images have gray-scale offset fields that make it difficult to divide the contours accurately. METHODS: To meet the above challenges, we propose an automatic brain tumor MRI data segmentation framework which is called AGSE-VNet. In our study, the Squeeze and Excite (SE) module is added to each encoder, the Attention Guide Filter (AG) module is added to each decoder, using the channel relationship to automatically enhance the useful information in the channel to suppress the useless information, and use the attention mechanism to guide the edge information and remove the influence of irrelevant information such as noise. RESULTS: We used the BraTS2020 challenge online verification tool to evaluate our approach. The focus of verification is that the Dice scores of the whole tumor, tumor core and enhanced tumor are 0.68, 0.85 and 0.70, respectively. CONCLUSION: Although MRI images have different intensities, AGSE-VNet is not affected by the size of the tumor, and can more accurately extract the features of the three regions, it has achieved impressive results and made outstanding contributions to the clinical diagnosis and treatment of brain tumor patients.
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Neoplasias Encefálicas/diagnóstico por imagem , Glioma/diagnóstico por imagem , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Neoplasias Encefálicas/patologia , Aprendizado Profundo , Glioma/patologia , HumanosRESUMO
High frequency is a solution to high data-rate underwater acoustic communications. Extensive studies have been conducted on high-frequency (>40 kHz) acoustic channels, which are strongly susceptible to surface waves. The corresponding channel statistics related to acoustic communications, however, still deserve systematic investigation. Here, an efficient channel modeling method based on statistical analysis is proposed. Three wind-associated environmental models are integrated into this hybrid model. The Texel-Marsen-Arsole spectral model is adopted to generate a three-dimensional shallow-water surface, which affects the Doppler shifts of large-scale paths. Small-scale micropaths are statistically analyzed and modeled according to the measured channels. The Hall-Novarini model is adopted to simulate the refraction and attenuation caused by wind-generated bubbles. An existing wind-generated noise model is applied to calculate the noise spectrum. The proposed model has been validated by the at-sea measurements collected in the Gulf of Mexico in 2016 and 2017. This model can be used to further analyze the channels at different carrier frequencies, bandwidths, and wind speeds for certain transmission conditions.
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The fluid inerter described by the fractional derivative model is introduced into the traditional nonlinear energy sink (NES), which is called fractional-order NES in this paper. The slowly varying dynamic equation (SVDE) of the system coupled with fractional-order NES is obtained by the complex averaging method, in which the fractional derivative term is treated using the fractional Leibniz theorem. Then, the discriminants (Δ, Δ1, and Δ2) of the number of equilibrium points are derived. By using the variable substitution method, the characteristic equation for judging the stability is established. The results show: (1) the approximate SVDE is sufficient to reflect the slowly varying characteristics of the system, which shows that the mathematical treatment of the fractional derivative term is reliable; (2) the discriminant conditions (Δ1, Δ2) can accurately reflect the number of equilibrium points, and the corresponding range of nonlinear parameter κ can be calculated when the system has three equilibrium points. The expressions of Δ1, Δ2 are simpler than Δ, which is suitable for analysis and design parameters; (3) the stability discrimination methods of schemes 1 and 2 are accurate. Compared with scheme 2, scheme 1 is more prone to various responses, especially various strongly and weakly modulated responses. In scheme 2, the inertia effect of mass can be completely replaced by integer order inerter. Compared with integer order inerter, the introduction of fractional order inerter, whether in series or in parallel, means that the amplitude of the equilibrium point on the NES vibrator is smaller, but it is also for this reason that it is not easy to produce a modulated response with scheme 2, and the vibration suppression effect of the main structure is not good.
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Water related problems, including water scarcity and pollution, have become increasingly urgent challenges especially in arid and semiarid regions. Two-dimensional water trading (2DWT) mechanism has been designed to unify the quantity and quality of water for relieving the water crisis. This study aims to develop a risk aversion optimization-two dimensional water trading model (RAO-2DWTM) for planning the regional-scale water resources management system (RWMS). This is the first attempt on planning RWMS through risk aversion optimization within the two-dimensional water trading framework. RAO-2DWTM cannot only support in-depth analysis regarding the effect of decision maker's preferences on system risk in different trading scenarios, but also reflect the interaction between water right trading and effluent trading, as well as disclose the optimal scheme of water resource management under uncertainties. Twenty four scenarios associated with different trading scenarios and robust levels are analyzed. The optimization scheme under the optimal risk control level is determined based on TOPSIS. Results revealed that 2DWT would bring high benefit with reduced risk cost, water deficit and emissions, implying the effectiveness of 2DWT mechanism. The results also disclosed that risk aversion behavior can mitigate water scarcity and pollution, as well as reduce risk cost, but may lead to some losses of system benefit. Consequently, decision makers should make trade-offs between system benefit and risk in identifying desired trading schemes.
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Desenvolvimento Sustentável , Água , China , Incerteza , Poluição da Água/prevenção & controle , Recursos HídricosRESUMO
Long-term exposure to heavy metals from high geological background area may lead to varieties of diseases. Therefore, risk assessment from agricultural products in these areas was crucial to ensure the health of customers. However, the effects of geological background on distributions of heavy metals and their accumulation in plant remain unclear. This study aimed to determine the distributions of mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr) and copper (Cu) in 1036 corn and rice samples collected from 9 locations in Guizhou province and to evaluate their health risks. The concentrations of Hg, Cd, As, Pb, Cr and Cu in these two crops were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), and their health risk were estimated by the target risk quotient approaches. Results showed that the mean concentrations of Hg, Cd, As, Pb, Cr and Cu in corn and rice were 0.01, 0.07, 0.06, 0.27, 0.56 and 1.86 mg/kg which were lower than their respective maximum allowable concentrations (MAC) of 0.02, 0.20, 0.70, 0.20, 0.50 and 10.00 mg/kg except Pb and Cr. The concentrations of Cr and Cu in corn were higher than in rice while Cd, As and Pb in rice were higher than in corn. Moreover, the distributions of Hg, Cd and Cu in corn and rice samples were mainly observed from QDN located at southeast of Guizhou province while Pb, As and Cr were most detected at ZY, QXN and BJ areas, southwest zone. The hazard indices (HIs) values for corn and rice were 0.20 and 2.61. The high HIs (> 1) in rice indicated that the health risk of heavy metals in rice was relatively high and Pb was the major component that attributed to the risk, followed by Cd. These results could provide a reference for the distributions of heavy metals in agricultural products in Guizhou province under crop cultivation conditions, and to provide scientific basis for health risk assessment and ensure food safety.
Assuntos
Arsênio , Mercúrio , Metais Pesados , Oryza , Poluentes do Solo , Arsênio/análise , Cádmio/análise , China , Cromo/análise , Monitoramento Ambiental , Chumbo/análise , Mercúrio/análise , Metais Pesados/análise , Oryza/química , Medição de Risco , Solo/química , Poluentes do Solo/análise , Zea maysRESUMO
Naringenin (NAR) is a natural flavonoid which exerts extensive biological activity, including anti-oxidation, anti-inflammation, anti-cancer, immune regulation and so on. However, the effect and mechanism of NAR in the alveolar bone regeneration are still unclear, which limits its clinical use. Hence, we investigated the effects of NAR in the proliferation, osteogenic and endothelial differentiation of human periodontal ligament stem cells (hPDLSCs) and explore the possible mechanism. The results showed that the proper concentrations (100 nM-10 µM) of NAR can promote the proliferation rate, osteogenic and endothelial differentiation of hPDLSCs. And the 1 µM NAR had the best proliferation promoting effect, while the 10 µM NAR had the best ability of promoting osteogenic and endothelial differentiation. NAR also promoted the mRNA expression of SDF-1 in a concentration dependent manner in PDLSCs. After adding the selective CXCR4 antagonist AMD3100, the osteogenic effect of NAR on PDLSCs is slightly enhanced, while the endothelial differentiation effect of NAR on hPDLSCs is attenuated. In summary, these results indicated that NAR promoted the proliferation of hPDLSCs, and promoted endothelial differentiation of hPDLSCs via SDF-1 to activate SDF-1/CXCR4 signaling pathway. However, the mechanism of which SDF-1 related signaling pathway is activated by NAR to enhance the osteogenic differentiation of hPDLSCs still needs to be investigated.