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The role of pescadillo1 (PES1) in regulating vascular permeability has been unknown. This study probes the role of PES1 and its mediated molecular mechanism in modulating vascular hyperpermeability in diabetic mice. Male C57BL/6J and db/db mice were fed a standard diet and a ketogenic diet (KD). Meanwhile, mouse vascular endothelial cells (MVECs) were treated with ß-hydroxybutyric acid (ß-HB), Pes1 siRNA or a Pes1 overexpression plasmid. Additionally, knockout (KO) of Pes1 in mice was applied. After 12 weeks of feedings, enhanced vascular PES1 expression in diabetic mice was inhibited by the KD. The suppression of PES1 was also observed in ß-HB-treated MVECs. In mice with Pes1 KO, the levels of vascular VEGF and PES1 were attenuated, while the levels of vascular VE-cadherin, Ang-1 and Occludin were upregulated. Similar outcomes also occurred after the knockdown of Pes1 in cultured MVECs, which were opposite to the effects induced by PES1 overexpression in MVECs. In vitro and in vivo experiments showed that high glucose concentration-induced increases in vascular paracellular permeability declined after MVECs were treated by ß-HB or by knockdown of Pes1. In contrast, increases in vascular permeability were induced by overexpression of Pes1, which were suppressed by coadministration of ß-HB in cultured endothelial cells. Similarly declines in vascular permeability were found by Pes1 knockdown in diabetic mice. Mechanistically, ß-HB decreased PES1-facilitated ubiquitination of VE-cadherin. The KD suppressed the diabetes-induced increase in PES1, which may result in vascular hyperpermeability through ubiquitination of VE-cadherin in type 2 diabetic mice.
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Permeabilidade Capilar , Diabetes Mellitus Tipo 2 , Dieta Cetogênica , Animais , Camundongos , Permeabilidade Capilar/fisiologia , Diabetes Mellitus Tipo 2/dietoterapia , Regulação para Baixo , Camundongos Endogâmicos C57BL , Hiperglicemia/prevenção & controle , Técnicas de Silenciamento de Genes , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Camundongos Knockout , Células Cultivadas , MasculinoRESUMO
We experimentally demonstrate a high-rate discretely modulated continuous-variable quantum key distribution over 80-km standard single-mode fiber with a 2.5 Gbaud, 16-symbol, two-ring constellation. With the help of well-designed digital signal processing algorithms, the excess noise of the system can be effectively suppressed. The achieved secret key rates are 49.02 Mbits/s, 11.86 Mbits/s, and 2.11 Mbits/s over 25-km, 50-km, and 80-km optical fiber, respectively, and achieve 67.4%, 70.0%, and 66.5% of the secret key rate performance of a Gaussian-modulated protocol. Our work shows that it is feasible to build a high-performance, long-distance continuous-variable quantum key distribution system with only a small constellation size.
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In continuous-variable quantum key distribution (CV-QKD), the key information are encoded on quadratures of the optical field, which are measured via balanced homodyne detector (BHD). The bandwidth of the BHD is one of key parameters for precise characterization of quantum states. We establish a theoretical model to analyze the impact of the BHD bandwidth and signal modulation patterns on the channel parameters estimation of CV-QKD systems. Based on the proposed model, the secure key rate of a practical CV-QKD system under different BHD bandwidths and signal modulation patterns are investigated. Our results show that insufficient BHD bandwidth will result in wrong estimate of the transmission loss and excess noise, which significantly affects the performance of CV-QKD systems. Given the BHD bandwidth, there exists an optimal signal repetition rate that maximizes the secure key rate. The BHD bandwidth requirement of the QKD system increases with the transmission distance for large duty cycle pulse. Furthermore, the root raised-cosine pulse signal modulation performs better than the square pulse signal modulation in general.
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The emergence of phytopathogenic bacteria resistant to antibacterial agents has rendered previously manageable plant diseases intractable, highlighting the need for safe and environmentally responsible agrochemicals. Inhibition of bacterial cell division by targeting bacterial cell division protein FtsZ has been proposed as a promising strategy for developing novel antibacterial agents. We previously identified 4'-demethylepipodophyllotoxin (DMEP), a naturally occurring substance isolated from the barberry species Dysosma versipellis, as a novel chemical scaffold for the development of inhibitors of FtsZ from the rice blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). Therefore, constructing structure-activity relationship (SAR) studies of DMEP is indispensable for new agrochemical discovery. In this study, we performed a structure-activity relationship (SAR) study of DMEP derivatives as potential XooFtsZ inhibitors through introducing the structure-based virtual screening (SBVS) approach and various biochemical methods. Notably, prepared compound B2, a 4'-acyloxy DMEP analog, had a 50% inhibitory concentration of 159.4 µM for inhibition of recombinant XooFtsZ GTPase, which was lower than that of the parent DMEP (278.0 µM). Compound B2 potently inhibited Xoo growth in vitro (minimum inhibitory concentration 153 mg L-1) and had 54.9% and 48.4% curative and protective control efficiencies against rice blight in vivo. Moreover, compound B2 also showed low toxicity for non-target organisms, including rice plant and mammalian cell. Given these interesting results, we provide a novel strategy to discover and optimize promising bactericidal compounds for the management of plant bacterial diseases.
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Oryza , Xanthomonas , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Divisão Celular , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Podofilotoxina/metabolismo , Podofilotoxina/farmacologia , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Octogenarians with esophageal cancer typically have a poor physical condition, reduced physiological reserves, and high postoperative mortality (POM). Extensive lymph node dissection increases surgical trauma and postoperative complications. The purpose of this study was to examine the associations between the number of dissected lymph nodes and short-term and long-term postoperative outcomes in octogenarians with thoracic esophageal cancer. METHODS: We examined the data of patients from the Surveillance, Epidemiology, and End Results database. We divided the patients into two groups in accordance with the number of lymph nodes dissected: patients with <15 examined lymph nodes (eLNs) and patients with ≥15 eLNs. Mortality was quantified at 30, 60, and 90 d after surgery. Univariable and multivariable logistic regression analyses were performed to identify predictors of 90-day mortality. Kaplan-Meier analysis and the log-rank test were used to analyze the overall survival and cause-specific survival of the patients. RESULTS: A total of 208 octogenarians with thoracic esophageal cancer were included in the analysis. The 30-day POM rates were 10.3% and 6.9%, the 60-day POM rates were 16.9% and 13.9%, and the 90-day POM rates were 21.3% and 19.4% for patients with <15 eLNs and ≥15 eLNs, respectively. However, the differences in POM between the two groups were statistically nonsignificant (all P > 0.05). In accordance with the multivariable logistic regression analysis, age and marital status were significantly associated with 90-day POM. Furthermore, no significant difference was found between the groups in terms of long-term survival. The 5-year overall survival rates were 29% and 26.8% (P = 0.719) and the 5-year cause-specific survival rates were 43.2% and 34.1% (P = 0.446) in patients with <15 eLNs and ≥15 eLNs, respectively. CONCLUSIONS: We have demonstrated that octogenarians undergoing esophagectomy are associated with an unacceptably high POM, and less extensive lymph node resection does not decrease POM. Octogenarians may not benefit from esophagectomy with lymphadenectomy. Additional studies need to be conducted to further guide clinicians performing highly selective esophagectomy.
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Neoplasias Esofágicas/cirurgia , Esofagectomia/efeitos adversos , Excisão de Linfonodo/efeitos adversos , Metástase Linfática/terapia , Complicações Pós-Operatórias/epidemiologia , Fatores Etários , Idoso de 80 Anos ou mais , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Esofagectomia/métodos , Esofagectomia/estatística & dados numéricos , Feminino , Seguimentos , Mortalidade Hospitalar , Humanos , Estimativa de Kaplan-Meier , Excisão de Linfonodo/estatística & dados numéricos , Linfonodos/patologia , Linfonodos/cirurgia , Masculino , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do TratamentoRESUMO
This study aimed to explore the underlying mechanism of linc01014 in oesophagus cancer gefitinib resistance. Gefitinib-resistant oesophagus squamous cell carcinoma (ESCC gefitinibR) cell lines were constructed by using different gefitinib treatment in FLO-1, KYAE-1, TE-8 and TE-5 cell lines and confirmed by MTS50 and proliferation assays. Expression of linc01014 was overexpressed/silenced in FLO-1 cells followed by gefitinib treatment, and then, the apoptosis-associated markers Bax and Bcl-2, and PI3KCA in PI3K signalling pathway were determined using Western blotting. MST50 and morphology analyses showed that ESCC gefitinibR cell lines presented obvious gefitinib resistance than their parental ESCC cell lines. ESCC gefitinibR cell lines showed significantly higher proliferation abilities than their parental ESCC cell lines after treating with gefitinib. Overexpression of linc01014 significantly inhibited the apoptosis of FLO-1 cells induced by gefitinib and silencing linc01014 obviously promoted the apoptosis of FLO-1 cells induced by gefitinib. Silencing linc01014 could significantly increase the gefitinib chemotherapy sensitivity of oesophagus cancer via PI3K-AKT-mTOR signalling pathway.
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Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Receptores ErbB/metabolismo , Neoplasias Esofágicas/genética , Gefitinibe/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Longo não Codificante/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Forma Celular/efeitos dos fármacos , Forma Celular/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Esofágicas/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , RNA Longo não Codificante/genética , Transdução de SinaisRESUMO
Germanium quantum dots (GeQDs), addressed by self-aligned and epitaxial silicon nanowires (SiNWs) as electrodes, represent the most fundamental and the smallest units that can be integrated into Si optoelectronics for 1550 nm wavelength detection. In this work, individual GeQD photodetectors have been fabricated based on a low temperature self-condensation of uniform amorphous Si (a-Si)/a-Ge bilayers at 300 °C, led by rolling indium (In) droplets. Remarkably, the diameter of the GeQD nodes can be independently controlled to achieve wider GeQDs for maximizing infrared absorption with narrower SiNW electrodes to ensure a high quality Ge/Si hetero-epitaxial connection. Importantly, these hetero GeQD/SiNW photodetectors can be deployed into predesigned locations for scalable device fabrication. The photodetectors demonstrate a responsivity of 1.5 mA W-1 and a photoconductive gain exceeding 102 to the communication wavelength signals, which are related to the beneficial type-II Ge/Si alignment, gradient Ge/Si epitaxial transition and a larger QD/NW diameter ratio. These results indicate a new approach to batch-fabricate and integrate GeQDs for ultra-compact Si-compatible photodetection and imaging applications.
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Neurodegenerative diseases mainly include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD). It is now found that these diseases may be related to autophagic dysfunction. The mechanism is due to abnormalities in autophagy, which lead to abnormal or misfolded proteins accumulating in the cytoplasm, nucleus, and extracellular inclusion bodies, causing neuronal organelle damage and synaptic dysfunction. Since these diseases are much complex, the effect of monotherapy is not significantly affected. There is still a need to strengthen the study of anti-neurodegenerative drugs. Natural products should be a good source for the new drug discovery since most of natural products are multiple-target compounds. In this chapter, we reviewed some progress on studying resveratrol, curcumin, tripterine, and paeoniflorin. These natural products can eliminate abnormal protein aggregates by regulating autophagy, and thereby these compounds are promising to be used in prevention and treatment of neurodegenerative diseases in the future.
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Autofagia/efeitos dos fármacos , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/patologia , Doença de Alzheimer , Humanos , Doença de Huntington , Doenças Neurodegenerativas/prevenção & controle , Doença de ParkinsonRESUMO
Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis and limited therapies, and transforming growth factor-ß1 (TGF-ß1) plays a central role in the pathogenesis of IPF. Here, we aimed to investigate the chemical constituents and biological activities of Hypericum longistylum and detect whether the isolated compounds inhibit the TGF-ß1/Smad3 signaling pathway to identify candidate compounds for the treatment of pulmonary fibrosis. Fifteen compounds (1-15) were isolated from H. longistylum and their structures were elucidated on the basis of spectroscopic analyses. An in vitro MTT assay was used to test the effect of these fifteen compounds on fibroblast cytotoxicity and vitality. Furthermore, their bioactivities were screened using a TGF-ß1/Smad3 pathway luciferase reporter in vitro. MTT screening found that compounds 1-15 had no deleterious effects on normal mouse lung fibroblasts and no significant inhibition of vitality. Luciferase assay showed that compounds 14 and 15 could significantly inhibit the TGF-ß1/Smad3 pathway with the inhibition rates of 67.92% and 93.10%, respectively. Both compounds can be used as lead compounds for structural modification and optimization to obtain more drug candidates for the treatment of pulmonary fibrosis.
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Antifibrinolíticos/farmacologia , Hypericum/química , Extratos Vegetais/farmacologia , Fibrose Pulmonar/tratamento farmacológico , Animais , Antifibrinolíticos/química , Antifibrinolíticos/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Fibroblastos/efeitos dos fármacos , Camundongos , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Transdução de Sinais/efeitos dos fármacos , Proteína Smad3/antagonistas & inibidores , Proteína Smad3/metabolismo , Relação Estrutura-Atividade , Fator de Crescimento Transformador beta1/antagonistas & inibidores , Fator de Crescimento Transformador beta1/metabolismoRESUMO
Stable organic nitroxyl radicals are an important class of catalysts for oxidation reactions, but their wide applications are hindered by their steric hinderance, high cost, complex operation, and separation procedures. Herein, NO2 in DMSO is shown to effectively catalyze the aerobic oxidative cleavage of C(OH)-C bonds to form a carboxylic group, and NO2 was generated inâ situ by decomposition of nitrates. A diverse range of secondary alcohols were selectively converted into acids in excellent yields in this transition-metal-free system without any additives. Preliminary results also indicate its applicability to depolymerize recalcitrant macromolecular lignin. Detail studies revealed that NO2 from nitrates promoted the reaction, and NO2 served as hydrogen acceptor and radical initiator for the tandem oxidative reaction.
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Biodegradable polymeric nanoparticles (NPs) have demonstrated significant potential to improve the systemic delivery of RNA interference (RNAi) therapeutics, such as small interfering RNA (siRNA), for cancer therapy. However, the slow and inefficient siRNA release inside tumor cells generally observed for most biodegradable polymeric NPs may result in compromised gene silencing efficacy. Herein, a biodegradable and redox-responsive NP platform, composed of a solid poly(disulfide amide) (PDSA)/cationic lipid core and a lipid-poly(ethylene glycol) (lipid-PEG) shell for systemic siRNA delivery to tumor cells, is developed. This newly generated NP platform can efficiently encapsulate siRNA under extracellular environments and can respond to the highly concentrated glutathione (GSH) in the cytoplasm to induce fast intracellular siRNA release. By screening a library of PDSA polymers with different structures and chain lengths, the optimized NP platform shows the unique features of i) long blood circulation, ii) high tumor accumulation, iii) fast GSH-triggered intracellular siRNA release, and iv) exceptionally effective gene silencing. Together with the facile polymer synthesis technique and robust NP formulation enabling scale-up, this new redox-responsive NP platform may become an effective tool for RNAi-based cancer therapy.
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Nanopartículas/química , Citoplasma/metabolismo , Glutationa/química , Humanos , Oxirredução , Interferência de RNARESUMO
Tin disulfide, as a promising high-capacity anode material for sodium-ion batteries, exhibits high theoretical capacity but poor practical electrochemical properties due to its low electrical conductivity. Constructing heterostructures has been considered to be an effective approach to enhance charge transfer and ion-diffusion kinetics. In this work, composites of SnS2 /Sb2 S3 heterostructures with reduced graphene oxide nanosheets were synthesized by a facile one-pot hydrothermal method. When applied as anode material in sodium-ion batteries, the composite showed a high reversible capacity of 642â mA h g-1 at a current density of 0.2â A g-1 and good cyclic stability without capacity loss in 100â cycles. In particular, SnS2 /Sb2 S3 heterostructures exhibited outstanding rate performance with capacities of 593 and 567â mA h g-1 at high current densities of 2 and 4â A g-1 , respectively, which could be ascribed to the dramatically improved Na+ diffusion kinetics and electrical conductivity.
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OBJECTIVE: To investigate the early predictors of necrotizing pneumonia in children. METHODS: The clinical data of 43 children with necrotizing pneumonia and 83 children with lobar pneumonia were retrospectively analyzed. Sex, age, the number of days with fever, laboratory examination results, and bronchoscopic findings were compared between the two groups. The multiple logistic regression analysis was used to identify the early predictors of necrotizing pneumonia. RESULTS: The necrotizing pneumonia group had a higher percentage of girls than the lobar pneumonia group (P<0.05). Compared with the lobar pneumonia group, the necrotizing pneumonia group had a larger number of days with fever, a higher peripheral blood white blood cell count (WBC), a higher percentage of neutrophils (NE%), and higher serum levels of high-sensitivity C-reactive protein (hs-CRP), albumin (Alb), and lactate dehydrogenase (LDH) (P<0.05). The necrotizing pneumonia group also had higher percentages of children with a large amount of sputum bolt under a bronchoscope which needed to be removed with biopsy forceps and children with rice-water-like bronchoalveolar lavage fluid (P<0.05). The multiple logistic regression analysis showed that being a female, the presence of sputum bolt under a bronchoscope which needed to be removed with biopsy forceps, the number of days with fever, WBC, hs-CRP, and LDH were independent predictors of necrotizing pneumonia. The receiver operating characteristic curve analysis showed that the cut-off values of the latter 4 predictors were 18.5â d, 15.1×10(9)/L, 121.5 mg/L, and 353.5 U/L, respectively. CONCLUSIONS: Increased WBC (≥15.1×10(9)/L), increased hs-CRP (≥121.5â mg/L), increased serum LDH (≥353.5 U/L), and the presence of sputum bolt under a bronchoscope which needs to be removed with biopsy forceps and rice-water-like bronchoalveolar lavage fluid may be the early predictors of necrotizing pneumonia in children.
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Pneumonia/diagnóstico , Proteína C-Reativa/análise , Criança , Pré-Escolar , Feminino , Humanos , L-Lactato Desidrogenase/sangue , Contagem de Leucócitos , Modelos Logísticos , Masculino , Necrose , Pneumonia/sangueRESUMO
BACKGROUND: China had 236 million internal migrants in 2012 and the majority of them migrated from rural to urban areas. The research based on medical and epidemical records found that the migrants had worse health than the urban residents, but the household and working place investigations reported better health status. The sick or unhealthy migrants are likely to return to their hometowns, which in turn may cause a report bias or over-estimation of the health status of rural-to-urban migrants in China. This paper explores the association of migration status and the physical and psychological health of Chinese internal migrants. METHODS: Nationally representative household survey data from the China Labor-force Dynamics Survey 2012 (CLDS) were used to analyze the association between the migration status and the health status of internal migrants in China. Migration status of the respondents was measured by hukou status and migration experience and all respondents were divided into four groups: returned population, migrant population, urban residents, and rural residents. Health status of respondents was measured by self-reported physical and psychological health. RESULTS: Migration experience was associated with the physical health of the returned population. The physical health of the returned population was worse than the migrant population and was distinguished by age and sex. The physical health status of migrant population was significantly better than rural residents, but not significantly better than urban residents. However, the association between migration status and psychological health was not statistically significant. Besides migration status, the socioeconomic status (SES) had a positive correlation with both physical and psychological health status, while occupational hazards exerted negative influence. CONCLUSION: The results indicate a tight association between migration experience and health status. The internal unhealthy migrants were more likely to return to their hometown and the migrant population might have limited health advantage.
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Emigração e Imigração/estatística & dados numéricos , Nível de Saúde , População Rural/estatística & dados numéricos , Migrantes/estatística & dados numéricos , Adulto , China/epidemiologia , Emprego/estatística & dados numéricos , Feminino , Humanos , Masculino , Transtornos Mentais/epidemiologia , Saúde Mental/estatística & dados numéricos , Pessoa de Meia-Idade , Dinâmica Populacional , Análise de RegressãoRESUMO
BACKGROUND: To compare the value of adipose tissues in abdomen and lumbar vertebra for predicting Crohn's disease (CD) activity based on chemical shift encoded magnetic resonance imaging (CSE-MRI). METHODS: 84 CD patients were divided into remission, mild, and moderate-severely groups based on CD activity index (CDAI). Differences in different adipose parameters [subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), mesenteric fat index (MFI), and bone marrow fat fraction (BMFF)] and blood inflammatory indicators among three groups, as well as the correlation of above parameters and CDAI were analyzed. The areas under the receiver-operating characteristic curves (AUCs) for the parameters selected by multivariate logistic regression analysis for predicting active CD were calculated. RESULTS: There were no significant differences in VAT and MFI among three groups (both P > 0.05). The cross-sectional areas of SAT in moderate-severe group were significantly lower than those in remission group (P = 0.014). BMFF values of remission group were significantly higher than those in the mild and moderate-severe groups (both P < 0.001). BMFF was negatively correlated with CDAI (r = -0.595, P < 0.001). SAT exhibited no significant correlation with CDAI. Erythrocyte sedimentation rate (ESR) and BMFF were the independent predictors of CDAI. Both combined had a higher diagnostic efficacy for active CD with an AUC of 0.895. CONCLUSIONS: BMFF is the best marker for predicting CD activity in fat parameters of abdomen and lumbar vertebra based on CSE-MRI. The model based on BMFF and ESR has a high efficiency in predicting active CD. TRIAL REGISTRATION: No. 22 K164 (Registered 18-07-2022).
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Tecido Adiposo , Doença de Crohn , Vértebras Lombares , Imageamento por Ressonância Magnética , Humanos , Doença de Crohn/diagnóstico por imagem , Masculino , Feminino , Imageamento por Ressonância Magnética/métodos , Adulto , Tecido Adiposo/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Pessoa de Meia-Idade , Abdome/diagnóstico por imagem , Adulto Jovem , Gordura Intra-Abdominal/diagnóstico por imagem , Curva ROCRESUMO
Objective: This study analyzed the popularity of TikTok health knowledge popularization accounts with the objective of creating a template for accounts suited to widely disseminating information, thereby enhancing the public's access to health knowledge on a broader scale. Methods: This study is based on 40 Chinese TikTok short video accounts that were active from February to April 2022 and were engaged in health science popularization. Data were validated by structured calibration using three qualitative anchors. It employs the "content-context" and the elaboration likelihood models as the theoretical framework. A qualitative comparative analysis is used to explore the factors affecting the popularity of this type of account mechanism. Results: Among the nine variables involved in the calculation, one reached 0.909091, demonstrating that the number of followers was both a necessary factor and a condition for the popularity of short health science video accounts. There were 16 paths in the complex solution with a consistency of 1, and their overall coverage reached 0.878788, indicating that approximately 87% of the cases could be explained. From the spread of the content and communication situation, professional medical knowledge, current hot topics, professionals, and serious issues were the most likely combinations for rapid spread. From the perspective of the central and edge paths, "likes" exceeding 100,000 and fans exceeding 1 million were essential combinations. Conclusions: The dissemination of medical knowledge has gained significant traction, especially with regard to trending and popular topics. When it comes to the tone of communication, a serious style proved effective in fostering what can be termed "hot communication." From the standpoint of central and peripheral paths, it is crucial that the number of likes in the past month and the total number of fans surpass 100,000 and one million, respectively.
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In this study, the hysteretic behavior of a novel frictional energy dissipation steel truss (FED-ST) is examined. The proposed FED-ST incorporates a friction damper with brass as the friction material into the top chord of traditional truss to improve the seismic performance of the staggered truss framing systems. A FED-ST specimen with a scale of 1:2.5 was subjected to a hysteresis test. The hysteretic behavior, ductility, and energy dissipation capability were analyzed considering the test findings. It is demonstrated that the FED-ST specimen has favorable ductility and an energy dissipation capacity that is 7.3 times more than that of a conventional truss specimen. The test findings were then used to compare and validate a finite element (FE) model. The FE analysis results are in strong agreement with the test results, demonstrating the validity of the modeling approach. To further investigate the impact of the cover plate width on the behavior of the FED-ST, preliminary parametric research was also carried out.
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The traditional two-wheeled self-balancing robot can travel quickly in a flat road environment, and it is easy to destabilize and capsize when passing through a bumpy road. To improve the passing ability of a two-wheeled robot, a new wheel-legged two-wheeled robot is developed. A seven-link leg structure is proposed through the comprehensive design of mechanism configuration, which decouples the balanced motion and leg motion of the robot. Based on the Euler-Lagrange method, the dynamic model of the system is obtained by applying the nonholonomic dynamic Routh equation in the generalized coordinate system. The robot's state space is divided according to the robot's height, and the Riccati equation is solved in real-time by the linear quadratic regulator (LQR) method to complete the balance and motion control of the robot. The robot leg motion control is achieved based on the active disturbance rejection control (ADRC) way. A robot simulation model is built on Recurdyn to verify the algorithm's feasibility, and then an experimental prototype is built to demonstrate the algorithm's effectiveness. The experimental results show that the control method based on LQR and ADRC can make the robot pass through the bumpy road.
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To improve the seismic performance of a staggered truss steel framing system, the basic force unit in the truss system is replaced by a friction energy dissipation truss. The difference between a friction energy dissipation truss and an ordinary truss is that the upper chord is a friction energy dissipation composite chord. In this paper, we investigate the effects of the number of bolts and the friction surface on the energy dissipation capacity of the chord by a quasi-static test on six composite chord specimens at a scale of 1:2. The results show that the hysteresis curves of friction energy dissipation composite chords are ideal rectangles, and the energy dissipation capacity is excellent. The more bolts there are in the specimen, the slower the energy dissipation capacity of the chord decreases. Among the different friction surface specimens, the energy dissipation capacity of the aluminum friction plate specimen decays the fastest, while the energy dissipation capacity of the shot-blasted treated specimen decays substantially after the first cycle. Friction plates can improve the stability of the hysteresis properties. Based on the test results, this paper proposes a calculation method for the ultimate bearing capacity of the composite chord, which provides a basis for the design of a friction energy dissipation truss. In addition, we studied the effects of different bolt clamping forces and slotted bolt hole lengths on the energy dissipation capacity of composite chords by establishing a finite element analysis. It was shown that as the clamping force of the bolt increases, the energy dissipation capacity of the specimen becomes stronger but the stability decreases. The energy dissipation capacity of the chord is close to a linear relationship with the slotted bolt hole lengths; thus, increasing the slotted bolt hole lengths within the allowable range of inter-story drifts can enhance the energy dissipation capacity of the chord. Finally, we propose the design method of the angle steel by analyzing the force of the chord.
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As an attractive semiconductor photocatalyst, (CuInS2)x-(ZnS)y has been intensively studied in photocatalysis, due to its unique layered structure and stability. Here, we synthesized a series of CuxIn0.25ZnSy photocatalysts with different trace Cu+-dominated ratios. The results show that doping with Cu+ ions leads to an increase in the valence state of In and the formation of a distorted S structure, simultaneously inducing a decrease in the semiconductor bandgap. When the doping amount of Cu+ ions is 0.04 atomic ratio to Zn, the optimized Cu0.04In0.25ZnSy photocatalyst with a bandgap of 2.16 eV shows the highest catalytic hydrogen evolution activity (191.4 µmol.h-1). Subsequently, among the common cocatalysts, Rh loaded Cu0.04In0.25ZnSy gives the highest activity of 1189.8 µmol·h-1, corresponding to an apparent quantum efficiency of 49.11 % at 420 nm. Moreover, the internal mechanism of photogenerated carrier transfer between semiconductors and different cocatalysts is analyzed by the band bending phenomenon.