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Non-Hodgkin lymphoma (NHL) is a lymphoproliferative disorder derived from either B or T lymphocytes. Among NHL, activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL) and T cell non-Hodgkin lymphomas (T-NHL) are poor prognosis and aggressive subtypes. Macrophages are professional phagocytic cells and dendritic cells (DCs) are professional antigen-presenting cells in immune system. Doxorubicin (Dox) and Etoposide (ET) are the most effective anti-cancer drugs. A20 and CYLD are negative regulators of NF-κB-dependent functions in many cell types. Little is known about the roles of A20 and CYLD in regulating functions of DCs and macrophages from NHL. The present study, therefore, explored whether A20/CYLD expression contributes to functions of DCs and macrophages from NHL. To this end, blood samples of seventy-nine patients with ABC DLBCL and T-NHL were examined. Gene expression profile was determined by quantitative RT-PCR and immunophenotype, cell apoptosis and phagocytosis by flow cytometry. As a result, immunophenotypic analysis showed that the numbers of CD13+CD117-, CD56+CD40+ and CD23+CD40+ expressing cells were significantly elevated in ABC DLBCL cases compared to healthy individuals and T-NHL patients. Interestingly, upon treatment of Dox and ET, the phagocytosis of lymphoma cells was significantly reduced by CD11c+CD123- DCs and the percentage of CD56+ mature DCs was significantly enhanced in ABC DLBCL patients only in the presence of A20 siRNA, but not CYLD siRNA. In conclusion, ABC DLBCL patients with low A20 expression were defective in elimination of lymphoma cells by DCs and linked to killer DC expansion in circulation.
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Células Dendríticas , Linfoma Difuso de Grandes Células B , Fagocitose , Proteína 3 Induzida por Fator de Necrose Tumoral alfa , Humanos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Fagocitose/efeitos dos fármacos , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/metabolismo , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Feminino , Linfoma Difuso de Grandes Células B/patologia , Linfoma Difuso de Grandes Células B/imunologia , Pessoa de Meia-Idade , Masculino , Linfoma não Hodgkin/patologia , Linfoma não Hodgkin/imunologia , Apoptose/efeitos dos fármacos , Idoso , Adulto , Macrófagos/metabolismo , Macrófagos/imunologia , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Linfócitos B/imunologia , Linfócitos B/metabolismo , ImunofenotipagemRESUMO
The recently uncovered two-dimensional materials serve as versatile building blocks for electronic devices. In this study, we methodically investigate the impact of substrate-induced strain and exchange field effects on the electronic density of states (EDOS) and electronic heat capacity (EHC) of single-layer ß12-borophene. Utilizing the Green's function approach, we compute these functions. The van Hove singularities in EDOS are observed to shift with strain, and depending on the direction and strength of the exchange field, the number of singularities increases. All these responses can be attributed to the renormalization of the velocity of electronic bands. Additionally, the inherent Schottky anomaly (an unusual peak at low temperatures) in the EHC undergoes a notable shift to higher and lower temperatures and variations in the intensity of the EHC due to substrate effects.
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In this study, the anti-osteogenic properties of the volatile oil extracted from Homalomena gigantea rhizome using ethyl acetate (EtOAc) and methanol (MeOH) were examined. Gas chromatography-mass spectrometry (GC-MS) was employed for the identification of volatile components. Following this, bioassays were performed to evaluate their effects on osteogenesis, encompassing parameters like cell viability, osteoblast differentiation, collagen synthesis and mineralization. The GC-MS analysis revealed 19 compounds in the EtOAc extract and 36 compounds in the MeOH extract. In the MeOH extract, major constituents included bis(2-ethylhexyl) terephthalate (13.83%), linalool (9.58%), palmitic acid (6.55%) and stearic acid (4.29%). The EtOAc extract contained bis(2-ethylhexyl) terephthalate (16.64%), palmitic acid (5.60%) and stearic acid (3.11%) as the predominant components. Both the EtOAc and MeOH extracts of H. gigantea exhibited promising potential for further investigation in anti-osteoporosis research. These findings contribute to the exploration of natural compounds with potential anti-osteoporotic properties, expanding our understanding of their therapeutic potential.
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Cromatografia Gasosa-Espectrometria de Massas , Óleos Voláteis , Osteogênese , Extratos Vegetais , Rizoma , Osteogênese/efeitos dos fármacos , Rizoma/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Animais , Sobrevivência Celular/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Camundongos , Ácido Palmítico/farmacologia , Monoterpenos Acíclicos/farmacologiaRESUMO
BACKGROUND: The open-label RECOVERY study reported improved survival in hospitalized, SARS-CoV-2 seronegative patients treated with casirivimab and imdevimab (CAS + IMD). METHODS: In this phase 1/2/3, double-blind, placebo-controlled trial conducted prior to widespread circulation of Delta and Omicron, hospitalized COVID-19 patients were randomized (1:1:1) to 2.4â g or 8.0â g CAS + IMD or placebo, and characterized at baseline for viral load and SARS-CoV-2 serostatus. RESULTS: In total, 1336 patients on low-flow or no supplemental (low-flow/no) oxygen were treated. The primary endpoint was met in seronegative patients, the least-squares mean difference (CAS + IMD versus placebo) for time-weighted average change from baseline in viral load through day 7 was -0.28 log10 copies/mL (95% confidence interval [CI], -.51 to -.05; P = .0172). The primary clinical analysis of death or mechanical ventilation from day 6 to 29 in patients with high viral load had a strong positive trend but did not reach significance. CAS + IMD numerically reduced all-cause mortality in seronegative patients through day 29 (relative risk reduction, 55.6%; 95% CI, 24.2%-74.0%). No safety concerns were noted. CONCLUSIONS: In hospitalized COVID-19 patients on low-flow/no oxygen, CAS + IMD reduced viral load and likely improves clinical outcomes in the overall population, with the benefit driven by seronegative patients, and no harm observed in seropositive patients. CLINICAL TRIALS REGISTRATION: NCT04426695.
Lay Summary . Monoclonal antibody therapies that block the virus that causes COVID-19 (SARS-CoV-2) can prevent patients from being hospitalized. We hypothesized that these antibodies may also benefit patients who are already hospitalized with COVID-19. Therefore, we performed a study to determine if the monoclonal antibody combination of casirivimab and imdevimab (CAS + IMD) can decrease the amount of virus in the nose of hospitalized patients and prevent the disease from becoming more severe. The study, conducted from June 2020 to April 2021, found that CAS + IMD treatment reduced the amount of virus in these patients, and may reduce their chance of dying or needing a ventilator (a machine that helps patients breathe). Patients were examined in 2 groups: those whose immune systems, at the start of the study, had not produced their own antibodies to fight SARS-CoV-2 (seronegative patients); or those that had already produced their own antibodies (seropositive patients) at the start of the study. Seronegative patients benefited the most from CAS + IMD. No safety concerns related to CAS + IMD were observed. These results demonstrate that monoclonal antibody therapy can help hospitalized patients with COVID-19 and may decrease their chances of needing assistance to breathe or dying.
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COVID-19 , Humanos , SARS-CoV-2 , Método Duplo-Cego , Tratamento Farmacológico da COVID-19RESUMO
Nitric oxide (NO) removal by photocatalytic oxidation over g-C3N4 has achieved more efficient results. However, there is a concern about the high NO-to-NO2 conversion yield of products, which is not suitable for the photocatalytic NO reaction. In this study, we modify g-C3N4 by WO3 nanoplates for the first time for photocatalytic NO oxidation over a WO3/g-C3N4 composite to enhance the green product selectivity under atmospheric conditions. The results indicate that the photocatalytic efficiency for NO removal by the WO3/g-C3N4 composite is drastically improved and achieves 52.5%, which is approximately 2.1 times higher than that of pure g-C3N4. Significantly, the green product (NO3-) selectivity of the WO3/g-C3N4 composite is 8.7 times higher than that of pure g-C3N4, and the selectivity remained high even after five cycles of photocatalytic tests. We also conclude that the enhanced green product selectivity of photocatalytic NO oxidation by the WO3/g-C3N4 composite is due to the separation and acceleration of the photogenerated charges of the WO3/g-C3N4 S-scheme heterojunction.
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INTRODUCTION: In recent years, both stromal vascular fraction (SVF) from adipose tissue and mesenchymal stem cells (MSC) from adipose tissues were extensively used in both preclinical and clinical treatment for various diseases. Some studies reported differences in treatment efficacy between SVFs and MSCs in animals as well as in humans. Therefore, this study is aimed to evaluate the immune modulation and angiogenic potential of SVFs and MSCs from the same SVF samples to support an explanation when SVFs or MSCs should be used. METHODS: The adipose tissue samples from ten female donors with consent forms were collected. SVFs from these samples were isolated according to the published protocols. The existence of mesenchymal cells that positive with CD44, CD73, CD90, and CD105 and endothelial progenitor cells that positive with CD31 and CD34 was determined using flow cytometry. Three samples of SVFs with similar percentages of mesenchymal cell portion and endothelial progenitor cell portion were used to isolate MSCs. Obtained MSCs were confirmed as MSCs using the ISCT minimal criteria. To compare the immune modulation of SVF and MSCs, the mixed lymphocyte assay was used. The lymphocyte proliferation, as well as IFN-gamma and TNF-alpha concentrations, were determined. To compare the angiogenic potential, the angiogenesis in quail embryo assay was used. The angiogenesis efficacy was measured based on the vessel areas formed in the embryos after 7 days. RESULTS: The results showed that all SVF samples contained the portions of mesenchymal cells and endothelial progenitor cells. MSCs from SVFs meet all minimal criteria of MSCs that suggested by ISCT. MSCs from SVFs efficiently suppressed the immune cell proliferation compared to the SVFs, especially at ratios of 1:4 (1 MSCs: 4 immune cells). MSCs also inhibited the IFN-gamma and TNF-alpha production more efficiently than SVFs (p < 0.05). However, in quail embryo models, SVFs triggered the angiogenesis and neovessel formation better than MSCs with more significant vessel areas after 7 days (p < 0.05). CONCLUSION: This study suggested that SVFs and MSCs have different potentials for immune modulation and angiogenesis. SVFs help the angiogenesis better than MSCs, while MSCs displayed the more significant immune modulation. These results can guide the usage of SVFs or MSCs in disease treatment.
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Recent reviews have reinforced sponge-associated bacteria as a valuable source of structurally diverse secondary metabolites with potent biological properties, which makes these microbial communities promising sources of new drug candidates. However, the overall diversity of secondary metabolite biosynthetic potential present in bacteria is difficult to access due to the fact that the majority of bacteria are not readily cultured in the laboratory. Thus, use of cultivation-independent approaches may allow accessing "silent" and "cryptic" secondary metabolite biosynthetic gene clusters present in bacteria that cannot yet be cultured. In the present study, we investigated the diversity of secondary metabolite biosynthetic gene clusters (BGCs) in metagenomes of bacterial communities associated with three sponge species: Clathria reinwardti, Rhabdastrella globostellata, and Spheciospongia sp. The results reveal that the three metagenomes contain a high number of predicted BGCs, ranging from 282 to 463 BGCs per metagenome. The types of BGCs were diverse and represented 12 different cluster types. Clusters predicted to encode fatty acid synthases and polyketide synthases (PKS) were the most dominant BGC types, followed by clusters encoding synthesis of terpenes and bacteriocins. Based on BGC sequence similarity analysis, 363 gene cluster families (GCFs) were identified. Interestingly, no GCFs were assigned to pathways responsible for the production of known compounds, implying that the clusters detected might be responsible for production of several novel compounds. The KS gene sequences from PKS clusters were used to predict the taxonomic origin of the clusters involved. The KS sequences were related to 12 bacterial phyla with Actinobacteria, Proteobacteria, and Firmicutes as the most predominant. At the genus level, the KSs were most related to those found in the genera Mycolicibacterium, Mycobacterium, Burkholderia, and Streptomyces. Phylogenetic analysis of KS sequences resulted in detection of two known 'sponge-specific' BGCs, i.e., SupA and SwfA, as well as a new 'sponge-specific' cluster related to fatty acid synthesis in the phylum Candidatus Poribacteria and composed only by KS sequences of the three sponge-associated bacterial communities assessed here.
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Actinobacteria , Poríferos , Actinobacteria/genética , Bactérias/genética , Vias Biossintéticas/genética , Família Multigênica/genética , Filogenia , Poríferos/microbiologia , AnimaisRESUMO
The deadly outbreak of the second wave of Covid-19, especially in worst hit lower-middle-income countries like India, and the drastic rise of another growing epidemic of Mucormycosis, call for an efficient mathematical tool to model pandemics, analyse their course of outbreak and help in adopting quicker control strategies to converge to an infection-free equilibrium. This review paper on prominent pandemics reveals that their dispersion is chaotic in nature having long-range memory effects and features which the existing integer-order models fail to capture. This paper thus puts forward the use of fractional-order (FO) chaos theory that has memory capacity and hereditary properties, as a potential tool to model the pandemics with more accuracy and closeness to their real physical dynamics. We investigate eight FO models of Bombay plague, Cancer and Covid-19 pandemics through phase portraits, time series, Lyapunov exponents and bifurcation analysis. FO controllers (FOCs) on the concepts of fuzzy logic, adaptive sliding mode and active backstepping control are designed to stabilise chaos. Also, FOCs based on adaptive sliding mode and active backstepping synchronisation are designed to synchronise a chaotic epidemic with a non-chaotic one, to mitigate the unpredictability due to chaos during transmission. It is found that severity and complexity of the models increase as the memory fades, indicating that FO can be used as a crucial parameter to analyse the progression of a pandemic. To sum it up, this paper will help researchers to have an overview of using fractional calculus in modelling pandemics more precisely and also to approximate, choose, stabilise and synchronise the chaos control parameter that will eliminate the extreme sensitivity and irregularity of the models.
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BACKGROUND: The Project Extension for Community Healthcare Outcomes (ECHO) model is considered a platform for academic medical centers to expand their healthcare workforce capacity to medically underserved populations. It has been known as an effective solution of continuing medical education (CME) for healthcare workers that used a hub-and-spoke model to leverage knowledge from specialists to primary healthcare providers in different regions. In this study, we aim to explore the views of healthcare providers and hospital leaders regarding the feasibility, acceptability, and sustainability of Project ECHO for pediatricians. METHODS: This qualitative study was conducted at the Vietnam National Children's Hospital and its satellite hospitals from July to December 2020. We conducted 39 in-depth interviews with hospital managers and healthcare providers who participated in online Project ECHO courses. A thematic analysis approach was performed to extract the qualitative data from in-depth interviews. RESULTS: Project ECHO shows high feasibility when healthcare providers find motivated to improve their professional knowledge. Besides, they realized the advantages of saving time and money with online training. Although the courses had been covered fully by the Ministry of Health's fund, the participants said they could pay fees or be supported by the hospital's fund. In particular, the expectation of attaining the CME-credited certificates after completing the course also contributes to the sustainability of the program. Project ECHO's online courses should be improved if the session was better monitored with suitable time arrangements. CONCLUSIONS: Project ECHO model is highly feasible, acceptable, and sustainable as it brings great benefits to the healthcare providers, and is appropriate with the policy theme of continuing medical education of the Ministry of Health. We recommend that further studies should be conducted to assess the impact of the ECHO program, especially for patient and community outcomes.
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Área Carente de Assistência Médica , Pediatras , Criança , Estudos de Viabilidade , Pessoal de Saúde , Humanos , VietnãRESUMO
This study aimed to assess the diversity and antimicrobial activity of cultivable bacteria associated with Vietnamese sponges. In total, 460 bacterial isolates were obtained from 18 marine sponges. Of these, 58.3% belonged to Proteobacteria, 16.5% to Actinobacteria, 18.0% to Firmicutes, and 7.2% to Bacteroidetes. At the genus level, isolated strains belonged to 55 genera, of which several genera, such as Bacillus, Pseudovibrio, Ruegeria, Vibrio, and Streptomyces, were the most predominant. Culture media influenced the cultivable bacterial composition, whereas, from different sponge species, similar cultivable bacteria were recovered. Interestingly, there was little overlap of bacterial composition associated with sponges when the taxa isolated were compared to cultivation-independent data. Subsequent antimicrobial assays showed that 90 isolated strains exhibited antimicrobial activity against at least one of seven indicator microorganisms. From the culture broth of the isolated strain with the strongest activity (Bacillus sp. M1_CRV_171), four secondary metabolites were isolated and identified, including cyclo(L-Pro-L-Tyr) (1), macrolactin A (2), macrolactin H (3), and 15,17-epoxy-16-hydroxy macrolactin A (4). Of these, compounds 2-4 exhibited antimicrobial activity against a broad spectrum of reference microorganisms.
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Antibacterianos/farmacologia , Bacillus/isolamento & purificação , Poríferos/microbiologia , Animais , Organismos Aquáticos , Bacillus/genética , Fitoterapia , VietnãRESUMO
In this paper, we propose and study a two-layer network composed of a Petri net in the first layer and a ring of coupled Hindmarsh-Rose neurons in the second layer. Petri nets are appropriate platforms not only for describing sequential processes but also for modeling information circulation in complex systems. Networks of neurons, on the other hand, are commonly used to study synchronization and other forms of collective behavior. Thus, merging both frameworks into a single model promises fascinating new insights into neuronal collective behavior that is subject to changes in network connectivity. In our case, the Petri net in the first layer manages the existence of excitatory and inhibitory links among the neurons in the second layer, thereby making the chemical connections time-varying. We focus on the emergence of different types of collective behavior in the model, such as synchronization, chimeras, and solitary states, by considering different inhibitory and excitatory tokens in the Petri net. We find that the existence of only inhibitory or excitatory tokens disturbs the synchronization of electrically coupled neurons and leads toward chimera and solitary states.
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We combined advanced TEM (HRTEM, HAADF, EELS) with solid-state (SS)MAS NMR and electroanalytical techniques (GITT, etc.) to understand the site-specific sodiation of selenium (Se) encapsulated in a nanoporous carbon host. The architecture employed is representative of a wide number of electrochemically stable and rate-capable Se-based sodium metal battery (SMB) cathodes. SSNMR demonstrates that during the first sodiation, the Se chains are progressively cut to form an amorphous mixture of polyselenides of varying lengths, with no evidence for discrete phase transitions during sodiation. It also shows that Se nearest the carbon pore surface is sodiated first, leading to the formation of a core-shell compositional profile. HRTEM indicates that the vast majority of the pore-confined Se is amorphous, with the only localized presence of nanocrystalline equilibrium Na2Se2 (hcp) and Na2Se (fcc). A nanoscale fracture of terminally sodiated Na-Se is observed by HAADF, with SSNMR, indicating a physical separation of some Se from the carbon host after the first cycle. GITT reveals a 3-fold increase in Na+ diffusivity at cycle 2, which may be explained by the creation of extra interfaces. These combined findings highlight the complex phenomenology of electrochemical phase transformations in nanoconfined materials, which may profoundly differ from their "free" counterparts.
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Flash flood is one of the most dangerous hydrologic and natural phenomena and is considered as the top ranking of such events among various natural disasters due to their fast onset characteristics and the proportion of individual fatalities. Mapping the probability of flash flood events remains challenges because of its complexity and rapid onset of precipitation. Thus, this study aims to propose a state-of-the-art data mining approach based on a hybrid equilibrium optimized SysFor, namely, the HE-SysFor model, for spatial prediction of flash floods. A tropical storm region located in the Northwest areas of Vietnam is selected as a case study. For this purpose, 1866 flash-flooded locations and ten indicators were used. The results show that the proposed HE-SysFor model yielded the highest predictive performance (total accuracy = 93.8%, Kappa index = 0.875, F1-score = 0.939, and AUC = 0.975) and produced the better performance than those of the C4.5 decision tree (C4.5), the radial basis function-based support vector machine (SVM-RBF), the logistic regression (LReg), and deep learning neural network (DeepLNN) models in both the training and the testing phases. Among the ten indicators, elevation, slope, and land cover are the most important. It is concluded that the proposed model provides an alternative tool and may help for effectively monitoring flash floods in tropical areas and robust policies for decision making in mitigating the flash flood impacts.
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Tempestades Ciclônicas , Inundações , Mineração de Dados , Rios , VietnãRESUMO
Dye and heavy metal contaminants are mainly aquatic pollutants. Although many materials and methods have been developed to remove these pollutants from water, effective and cheap materials and methods are still challenging. In this study, highly porous hydroxyapatite/graphene oxide/chitosan beads (HGC) were prepared by a facile one-step method and investigated as efficient adsorbents. The prepared beads showed a high porosity and low bulk density. SEM images indicated that the hydroxyapatite (HA) nanoparticles and graphene oxide (GO) nanosheets were well dispersed on the CTS matrix. FT-IR spectra confirmed good incorporation of the three components. The adsorption behavior of the obtained beads to methylene blue (MB) and copper ions was investigated, including the effect of the contact time, pH medium, dye/metal ion initial concentration, and recycle ability. The HGC beads showed rapid adsorption, high capacity, and easy separation and reused due to the porous characteristics of GO sheets and HA nanoparticles as well as the rich negative charges of the chitosan (CTS) matrix. The maximum sorption capacities of the HGC beads were 99.00 and 256.41 mg g-1 for MB and copper ions removal, respectively.
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BACKGROUND: Triglyceride Glucose (TyG) index has been associated with an increased risk in cardiovascular events. Silent coronary disease is common in patients with type 2 diabetes. In Vietnam, a low-middle income country, the burden of cardiovascular disease is growing simultaneously with the epidemiologic transition. Our aim was to assess the prevalence of coronary stenoses (CS) in patients with type 2 diabetes and no history or symptom of cardiovascular disease and to investigate the association between TyG index and cardiovascular risk factors and both the presence and severity of CS. Futhermore, we assessed the value of TyG index in predicting subclinical CS. METHODS: This was a cross-sectional observational study. We recruited 166 patients at Ninh Thuan General Hospital, Vietnam. TyG index and HOMA-IR were calculated, and a coronary computed tomography angiography (CCTA) was performed. RESULTS: The population was classified according to tertiles of TyG index. The highest TyG values were associated with higher BMI, waist circumference, total cholesterol, LDL-cholesterol, triglycerides, plasma glucose, HbA1c levels and HOMA-IR, lower HDL-cholesterol, a higher incidence of metabolic syndrome and less frequent physical activity (p < 0.05 to < 0.0001). TyG index correlated with logHOMA-IR (p < 0.0001). CS ≥ 50% were present in 60 participants and 32 had coronary artery stenosis ≥ 70%. TyG index and HOMA-IR were significantly higher in patients with CS ≥ 70%. The number of narrowed coronary arteries and the degree of stenosis were associated with higher TyG index levels (p = 0.04 and < 0.005 respectively). A TyG index ≥ 10 was significantly associated with an increased risk of multiple coronary artery disease and of more severe CS. After adjusting for confounding factors, including logHOMA-IR, these risks remained mostly significant. A TyG index threshold at 10 resulted in 57% sensitivity and 75% specificity for predicting the presence of CS ≥ 70%. In subgroup analysis TyG index ≥ 10 was associated with an increased risk in CS ≥ 70% in patients treated with statin or antiplatelet therapy. CONCLUSION: More than one third of asymptomatic patients with type 2 diabetes had significant CS on CCTA. TyG index may be considered as a marker for insulin resistance and increased TyG index could identify patients with high risk of coronary artery stenoses and is associated with the number and the severity of artery stenoses.
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Doenças Assintomáticas , Glicemia/metabolismo , Estenose Coronária/sangue , Diabetes Mellitus Tipo 2/sangue , Triglicerídeos/sangue , Idoso , Índice de Massa Corporal , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Angiografia por Tomografia Computadorizada , Estenose Coronária/diagnóstico , Estenose Coronária/epidemiologia , Vasos Coronários , Estudos Transversais , Feminino , Hemoglobinas Glicadas/metabolismo , Fatores de Risco de Doenças Cardíacas , Humanos , Resistência à Insulina , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/epidemiologia , Pessoa de Meia-Idade , Prevalência , Comportamento Sedentário , Vietnã/epidemiologia , Circunferência da CinturaRESUMO
In this paper, we study the dynamics and control of a Caputo fractional difference form of the Duffing map. We use phase plots, bifurcation diagrams, and Lyapunov exponents to establish the existence of chaos over a wide range of fractional orders and examine the nature of the dynamics. Also, we present the 0-1 test to detect chaos and C0 complexity, which is an alternative nonlinear statistical measure that can quantify the regularity of a time series. In addition, we measure the approximate entropy to see the performance of our numerical results. Through phase plots and bifurcation diagrams, it is shown that the proposed fractional map exhibits a range of different dynamical behaviors including chaos and coexisting attractors. A one-dimensional feedback stabilization controller is proposed. The asymptotic convergence of the proposed controller is established by means of the stability theory of linear fractional order discrete-time systems. Simulation results have been carried out to illustrate the findings of the study.
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In this paper, the amplitude and the length of the business cycle are investigated. It is the first time the length of the business cycle based on the Goodwin model (one classical business cycle model) is discussed. The effect of the time delay of the economic policy and consumption on the amplitude and the length of the business cycle is studied. Meanwhile, the memory property of making economic policy is also considered. The theoretical amplitude of the business cycle is obtained by multiple-scale methods. The transitions of the amplitude induced by memory property and time delay are analyzed. How the economic parameter and random excitation affect the length of the business cycle is proposed. Based on the results, we can find that the time delay of both economic policy and consumption can induce the transitions. Moreover, the memory property of economic policy will change the critical value of the parameters when the transitions occur. In one typical induced investment function, the length of the business cycle is determined only by the autonomous investment and consumption. However, the length of the business cycle is not mainly affected by the autonomous investment and consumption in some other typical induced investment function. This states that the type of induced investment function has a very important role in determining the length of the business cycle.
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Coronavirus disease 2019 is a recent strong challenge for the world. In this paper, an epidemiology model is investigated as a model for the development of COVID-19. The propagation of COVID-19 through various sub-groups of society is studied. Some critical parameters, such as the background of mortality without considering the disease state and the speed of moving people from infected to resistance, affect the conditions of society. In this paper, early warning indicators are used to predict the bifurcation points in the system. In the interaction of various sub-groups of society, each sub-group can have various parameters. Six cases of the sub-groups interactions are studied. By coupling these sub-groups, various dynamics of the whole society are investigated.
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BACKGROUND: There are currently two markers used to monitor treatment response to anti-retroviral therapy (ART) in HIV-infected children: CD4 T-cell count and HIV viral load; but analysis of these could be challenging in resource-poor countries. The aim of this study was therefore to determine whether change in growth parameters such as weight-for-age Z score (WAZ), height-for-age Z score (HAZ) and body mass index-for-age Z score (BMIZ) is associated with treatment response in HIV-infected children. METHODS: This was a nested case-control study, in which the data were collected at enrolment and then periodically every 6 months for a total 36 month follow up of 107 HIV-infected children enrolled and treated at National Hospital of Pediatrics, Vietnam. RESULTS: At treatment initiation, WAZ, HAZ and BMIZ were not significantly higher in the treatment success (TS) group compared with the treatment failure (TF) group. After ART initiation, WAZ and HAZ increased, and this was significant in the TS group (from -1.5 to -0.54, P < 0.01 and from -2.06 to -0.84, P < 0.01, respectively). Low HAZ was significantly associated with TF (HR, 0.71; 95% CI: 0.54-0.92). CONCLUSION: Height-for-age Z score was the most sensitive growth parameter in prediction of the treatment response. In order to use growth parameters, particularly HAZ as a prognosis marker for TF in clinical practice, further research should be conducted to evaluate the role of growth parameters and their effects on treatment response.
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Antirretrovirais/uso terapêutico , Desenvolvimento Infantil/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Antropometria , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Seguimentos , Infecções por HIV/fisiopatologia , Humanos , Lactente , Masculino , Resultado do Tratamento , VietnãRESUMO
Today, four-dimensional chaotic systems are attracting considerable attention because of their special characteristics. This paper presents a non-equilibrium four-dimensional chaotic system with hidden attractors and investigates its dynamical behavior using a bifurcation diagram, as well as three well-known entropy measures, such as approximate entropy, sample entropy, and Fuzzy entropy. In order to stabilize the proposed chaotic system, an adaptive radial-basis function neural network (RBF-NN)-based control method is proposed to represent the model of the uncertain nonlinear dynamics of the system. The Lyapunov direct method-based stability analysis of the proposed approach guarantees that all of the closed-loop signals are semi-globally uniformly ultimately bounded. Also, adaptive learning laws are proposed to tune the weight coefficients of the RBF-NN. The proposed adaptive control approach requires neither the prior information about the uncertain dynamics nor the parameters value of the considered system. Results of simulation validate the performance of the proposed control method.