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Background: The purpose of this study was to evaluate the impact of glucose levels on admission, on the risk of 30-day major adverse cardiovascular events (MACEs) in patients with acute myocardial infarction (AMI), and to assess the difference in outcome between ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients. Methods: This study was a post hoc analysis of the Acute Coronary Syndrome Quality Improvement in Kerala Study, and 13,398 participants were included in the final analysis. Logistic regression models were used to assess the association between glucose levels on admission and the risk of 30-day MACEs, adjusting for potential confounders. Results: Participants were divided according to the glucose quintiles. There was a positive linear association between glucose levels at admission and the risk of 30-day MACEs in AMI patients [adjusted OR (95% CI): 1.05 (1.03, 1.07), p < 0.001]. Compared to participants with an admission glucose between 5.4 and 6.3 mmol/L, participants with the highest quintile of glucose level ( ≥ 10.7 mmol/L) were associated with increased risk of 30-day MACEs in the fully adjusted logistic regression model [adjusted OR (95% CI): 1.82 (1.33, 2.50), p < 0.001]. This trend was more significant in patients with STEMI (p for interaction = 0.036). Conclusions: In patients with AMI, elevated glucose on admission was associated with an increased risk of 30-day MACEs, but only in patients with STEMI.
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BACKGROUND: The association between serum potassium and atrial fibrillation (AF) recurrence after catheter ablation remains unclear. OBJECTIVE: The purpose of this study was to investigate whether preprocedural serum potassium influences AF recurrence in patients who underwent catheter ablation. METHODS: We used data of patients with AF who underwent de novo catheter ablation from the prospective Chinese Atrial Fibrillation Registry Study. Patients with prior ablation and without baseline serum potassium were excluded. The primary outcome was 1-year AF recurrence after a 3-month blanking period from the ablation procedure. Restricted cubic spline and Cox proportional models were used to compare outcomes across serum potassium categories. RESULTS: A total of 4838 patients with AF who underwent de novo catheter ablation was enrolled. At 1 year, AF recurrence occurred in 1347 patients (27.8%). The relationship between preprocedural serum potassium and 1-year AF recurrence after ablation presented as U shape (P for nonlinear = .048). Compared with the group of serum potassium within 4.41-4.60 mmol/L, the risk of AF recurrence increased significantly in the lowest serum potassium group (≤4.00 mmol/L) after multivariate analysis (hazard ratio [HR] 1.26; 95% confidence interval 1.06-1.51; P = .010). Other categories with lower or higher serum potassium levels including 4.01-4.20 mmol/L (HR 1.18), 4.21-4.40 mmol/L (HR 1.16), 4.61-4.80 mmol/L (HR 1.07), and ≥4.81 mmol/L (HR 1.11) showed nonsignificant higher recurrence risk. CONCLUSION: The relationship between preprocedural potassium and AF recurrence was U shaped, with an optimal potassium range (4.41-4.60 mmol/L). Lower potassium level is associated with increased AF recurrence risk after catheter ablation.
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BACKGROUND: It is still unclear whether small left ventricle (LV) is an adverse structural prognostic feature in patients with atrial fibrillation (AF). OBJECTIVES: The purpose of this study was to evaluate the association between small LV and risk of cardiovascular events in AF population. METHODS: From the China-AF registry, 7,764 patients with AF were enrolled and divided into groups with normal, small, and large LV size based on left ventricular end-diastolic dimension (LVEDD) measurement per the American Society of Echocardiography references. Cox models were used to assess the association between LV size or LVEDD with composite cardiovascular events (cardiovascular death, ischemic stroke or systemic embolism, or major bleeding). RESULTS: There were 308 (4.0%) participants assessed with small LV who were older, with lower body mass and blood pressure, and fewer comorbidities, and 429 (5.5%) were identified with large LV. Compared with the normal LV group, small LV and large LV were significantly associated with higher incidence of composite cardiovascular events (adjusted HR [aHR]: 1.54 [95% CI: 1.07-2.20] for small LV; aHR: 1.36 [95% CI: 1.02-1.81] for large LV) and cardiovascular death (aHR: 1.94 [95% CI: 1.14-3.28] for small LV; aHR: 1.83 [95% CI: 1.24-2.69] for large LV). Small LV was also associated with increased risk of major bleeding [aHR: 2.21 [95% CI: 1.01-4.86]). A U-shaped relationship between LVEDD and composite cardiovascular events was identified (Pnonlinear < 0.001). CONCLUSIONS: In a prospective AF cohort, small LV was independently associated with an increased risk of cardiovascular events, which needed consideration in risk stratification and management for patients with AF. (ChiCTR-OCH-13003729).
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Fibrilación Atrial , Ventrículos Cardíacos , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fibrilación Atrial/epidemiología , Fibrilación Atrial/complicaciones , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etiología , China/epidemiología , Ecocardiografía , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/fisiopatología , Tamaño de los Órganos , Estudios Prospectivos , Sistema de Registros , Medición de Riesgo/métodos , Factores de RiesgoRESUMEN
Secondary battery as an efficient energy conversion device has been highly attractive for alleviating the energy crisis and environmental pollution. Hierarchical porous carbon (HPC) materials with multiple sizes pore channels are considered as promising materials for energy conversion and storage applications, due to their high specific surface area and excellent electrical conductivity. Although many reviews have reported on carbon materials for different fields, systematic summaries about HPC materials for lithium storage are still rare. In this review, we first summarize the main preparation methods of HPC materials, including hard template method, soft template method, and template-free method. The modification methods including porosity and morphology tuning, heteroatom doping, and multiphase composites are introduced systematically. Then, the recent advances in HPC materials on lithium storage are summarized. Finally, we outline the challenges and future perspectives for the application of HPC materials in lithium storage.
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Background: Non-alcoholic fatty liver disease (NAFLD) is increasingly observed in non-obese individuals. The ZJU (Zhejiang University) index has been established as a new and efficient tool for detecting NAFLD, but the relationship between the ZJU index and NAFLD within non-obese individuals still remains unclear. Methods: A post-hoc evaluation was undertaken using data from a health assessment database by the Wenzhou Medical Center. The participants were divided into four groups based on the quartile of the ZJU Index. Cox proportional hazards regression, Kaplan-Meier analysis and tests for linear trends were used to evaluate the relationship between the ZJU index and NAFLD incidence. Subgroup analysis was conducted to test the consistency of the correlation between ZJU and NAFLD in subsgroups. Receiver operative characteristic (ROC) curve analysis was performed to evaluate the predictive performance of the ZJU index, compared with the Atherogenic index of plasma (AIP) and Remnant lipoprotein cholesterol (RLP-C) index. Results: A total of 12,127 were included in this study, and 2,147 participants (17.7%) developed NAFLD in 5 years follow-up. Participants in higher ZJU quartiles tended to be female and have higher liver enzymes (including ALP, GGT, ALT, AST), GLU, TC, TG, LDL and higher NAFLD risk. Hazard Ratios (HR) and 95% confidence intervals (CI) for new-onset NAFLD in Q2, Q3, and Q4 were 3.67(2.43 to 5.55), 9.82(6.67 to 14.45), and 21.67(14.82 to 31.69) respectively in the fully adjusted model 3. With increased ZJU index, the cumulative new-onset NAFLD gradually increased. Significant linear associations were observed between the ZJU index and new-onset NAFLD (p for trend all<0.001). In the subgroup analysis, we noted a significant interaction in sex, with HRs of 3.27 (2.81, 3.80) in female and 2.41 (2.21, 2.63) in male (P for interaction<0.01). The ZJU index outperformed other indices with an area under the curve (AUC) of 0.823, followed by AIP (AUC=0.747) and RLP-C (AUC=0.668). Conclusion: The ZJU index emerges as a promising tool for predicting NAFLD risk in non-obese individuals, outperforming other existing parameters including AIP and RLP-C. This could potentially aid in early detection and intervention in this specific demographic.
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Enfermedad del Hígado Graso no Alcohólico , Femenino , Humanos , Masculino , Pueblo Asiatico , China/epidemiología , Incidencia , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Estudios Prospectivos , Indicadores de SaludRESUMEN
BACKGROUND: Wearable devices based on the PPG algorithm can detect atrial fibrillation (AF) effectively. However, further investigation of its application on long-term, continuous monitoring of AF burden is warranted. METHOD: The performance of a smartwatch with continuous photoplethysmography (PPG) and PPG-based algorithms for AF burden estimation was evaluated in a prospective study enrolling AF patients admitted to Beijing Anzhen Hospital for catheter ablation from September to November 2022. A continuous Electrocardiograph patch (ECG) was used as the reference device to validate algorithm performance for AF detection in 30-s intervals. RESULTS: A total of 578669 non-overlapping 30-s intervals for PPG and ECG each from 245 eligible patients were generated. An interval-level sensitivity of PPG was 96.3% (95% CI 96.2%-96.4%), and specificity was 99.5% (95% CI 99.5%-99.6%) for the estimation of AF burden. AF burden estimation by PPG was highly correlated with AF burden calculated by ECG via Pearson correlation coefficient (R2 = 0.996) with a mean difference of -0.59 (95% limits of agreement, -7.9% to 6.7%). The subgroup study showed the robust performance of the algorithm in different subgroups, including heart rate and different hours of the day. CONCLUSION: Our results showed the smartwatch with an algorithm-based PPG monitor has good accuracy and stability in continuously monitoring AF burden compared with ECG patch monitors, indicating its potential for diagnosing and managing AF.
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Fibrilación Atrial , Humanos , Fibrilación Atrial/diagnóstico , Fotopletismografía/métodos , Estudios Prospectivos , Sensibilidad y Especificidad , Algoritmos , Electrocardiografía/métodosRESUMEN
The excellent image-generation ability of generative adversarial networks (GANs) has been widely used. However, training a GAN requires large-scale data support, which hinders in-depth development. Therefore, the research on stable training of GANs under limited data conditions is helpful to further expand the application scenarios. To solve this problem, a new network based on a dual-ways discriminator structure is designed, used to eliminate the problem that a single discriminator model is prone to overfitting under the condition of limited data. Then, the problem that the traditional data augmentation strategy is limited to pixel space and lacks attention to the overall structure and contour of the image is analyzed. An adaptive dynamic data augmentation strategy based on the Laplace convolution kernel is proposed from the frequency domain space, which realizes the purpose of implicitly increasing the training data in the training process. This new designed module improves the performance of the generative adversarial network. Through extensive experiments, it was confirmed that the new network, named FD-GAN, achieved prefer image generation ability, and its Fid score reached 4.58, 12.007, and 10.382 in the AFHQ-Cat, AFHQ-Dog, and TankDataSet datasets, respectively.
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Tissue repair and regeneration is a vital biological process in organisms, which is influenced by various internal mechanisms and microenvironments. Pulsed electromagnetic fields (PEMFs) are becoming a potential medical technology due to its advantages of effectiveness and non-invasiveness. Numerous studies have demonstrated that PEMFs can stimulate stem cell proliferation and differentiation, regulate inflammatory reactions, accelerate wound healing, which is of great significance for tissue regeneration and repair, providing a solid basis for enlarging its clinical application. However, some important issues such as optimal parameter system and potential deep mechanisms remain to be resolved due to PEMFs window effect and biological complexity. Thus, it is of great importance to comprehensively summarizing and analyzing the literature related to the biological effects of PEMFs in tissue regeneration and repair. This review expounded the biological effects of PEMFs on stem cells, inflammation response, wound healing and musculoskeletal disorders in order to improve the application value of PEMFs in medicine. It is believed that with the continuous exploration of biological effects of PEMFs, it will be applied increasingly widely to tissue repair and other diseases.
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Campos Electromagnéticos , Células Madre Mesenquimatosas , Diferenciación Celular , Cicatrización de Heridas , Células MadreRESUMEN
BACKGROUND: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) is reported to reduce incident atrial fibrillation (AF) in patients with or without diabetes; however, its cardiovascular (CV) benefit for AF patients remains unclear. SS AIMS: To investigate the effect of SGLT2i on the incidence of CV events in patients with AF. METHODS: Six randomized controlled trials (RCTs) assessing the effects of SGLT2i on CV outcomes in patients with or without AF were included (PROSPERO: CRD 42023431535). The primary endpoint was the composite outcome of heart failure (HF) hospitalization and CV death. Additionally, we assessed the effects of treatment in prespecified subgroups on HF hospitalization, CV death, and all-cause mortality. RESULTS: Among 38,529 participants from all trials, 5018 patients with AF were treated with SGLT2i. The follow-up period of these trials ranged from 2.3 to 3.3 years. SGLT2i treatment was significantly associated with the risk reduction of primary endpoint in patients with AF (risk ratio [RR] 0.81, 95% confidence interval [CI] 0.74-0.88; p < 0.001), consistent with the finding in the general population (p for interaction = 0.76). SGLT2i was also associated with a consistent reduction in the risk of HF hospitalization in patients with AF (RR 0.76, 95% CI 0.69-0.84; p < 0.001) or not (RR 0.72, 95% CI 0.64-0.80; p < 0.0001), with no statistical difference between them (p for interaction = 0.41). Meta-regression further revealed no significant association between the prevalence of HF with reduced ejection fraction or diabetes and the effect size of SGLT2i. CONCLUSIONS: The treatment effects of SGLT2i were associated with a lower incidence of CV events, especially HF hospitalization, in patients with AF.
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Fibrilación Atrial , Diabetes Mellitus , Insuficiencia Cardíaca , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Humanos , Fibrilación Atrial/tratamiento farmacológico , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/epidemiologíaRESUMEN
BACKGROUND: The association between sodium-glucose cotransporter 2 inhibitors (SGLT2i) and atrial fibrillation (AF) recurrence after catheter ablation among patients with diabetes and AF remains unclear. METHODS AND RESULTS: Patients with AF undergoing initial catheter ablation with a history of diabetes from the China AF registry were included. Patients using SGLT2i were identified and matched by propensity score with non-SGLT2i patients in a 1:3 ratio. The main outcome was AF recurrence during the 18-month follow-up. A total of 138 patients with diabetes with SGLT2i therapy and 387 without SGLT2i were analyzed. AF recurrence occurred in 37 patients (26.8%) in the SGLT2i group and 152 patients (39.3%) in the non-SGLT2i group during a total of 593.3 person-years follow-up. The SGLT2i group was associated with lower AF recurrence compared with the non-SGLT2i group (hazard ratio, 0.63 [95% CI, 0.44-0.90], P=0.007). A total of 4 studies were analyzed in our meta-analysis demonstrating that SGLT2i was associated with lower AF recurrence after catheter ablation (odds ratio, 0.61 [95% CI, 0.54-0.69]; P<0.001, I2=0.0%). CONCLUSIONS: Our prospective study coupled with a meta-analysis demonstrated a lower risk of AF recurrence with the use of SGLT2i among patients with diabetes after AF ablation.
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Fibrilación Atrial , Ablación por Catéter , Diabetes Mellitus , Humanos , Fibrilación Atrial/tratamiento farmacológico , Fibrilación Atrial/cirugía , Fibrilación Atrial/complicaciones , Puntaje de Propensión , Estudios Prospectivos , Factores de Riesgo , Resultado del Tratamiento , Recurrencia , Diabetes Mellitus/etiología , Ablación por Catéter/efectos adversos , Ablación por Catéter/métodos , Glucosa , SodioRESUMEN
BACKGROUND: Patients with atrial fibrillation (AF) and prior stroke history have a high risk of cardiovascular events despite anticoagulation therapy. It is unclear whether catheter ablation (CA) has further benefits in these patients. METHODS: AF patients with a previous history of stroke or systemic embolism (SE) from the prospective Chinese Atrial Fibrillation Registry study between August 2011 and December 2020 were included in the analysis. Patients were matched in a 1:1 ratio to CA or medical treatment (MT) based on propensity score. The primary outcome was a composite of all-cause death or ischemic stroke (IS)/SE. RESULTS: During a total of 4.1 ± 2.3 years of follow-up, the primary outcome occurred in 111 patients in the CA group (3.3 per 100 person-years) and in 229 patients in the MT group (5.7 per 100 person-years). The CA group had a lower risk of the primary outcome compared to the MT group [hazard ratio (HR) = 0.59, 95% CI: 0.47-0.74, P < 0.001]. There was a significant decreasing risk of all-cause mortality (HR = 0.43, 95% CI: 0.31-0.61, P < 0.001), IS/SE (HR = 0.73, 95% CI: 0.54-0.97, P = 0.033), cardiovascular mortality (HR = 0.32, 95% CI: 0.19-0.54, P < 0.001) and AF recurrence (HR = 0.33, 95% CI: 0.30-0.37, P < 0.001) in the CA group compared to that in the MT group. Sensitivity analysis generated consistent results when adjusting for time-dependent usage of anticoagulants. CONCLUSIONS: In AF patients with a prior stroke history, CA was associated with a lower combined risk of all-cause death or IS/SE. Further clinical trials are warranted to confirm the benefits of CA in these patients.
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Nano scale topography scaffold is more bioactive and biomimetic than smooth fiber topographies. Tendon stem cells (TSCs) play important roles in the tendinogenesis of tendon tissue engineering, but the effects and mechanisms of nano topography on TSC behavior are still unclear. This study determined whether the morphology, proliferation, cytoskeleton, and differentiation of TSCs are affected by topography of scaffold in vitro. The porous PA56 scaffolds were prepared with different concentration ratios of glycerol as the molecular template by electrospinning. Its topological characteristics, hydrophilicity, and degradation properties varied with glycerol proportion and movement rate of the receiving plate. Porous fibers promoted the proliferation of TSCs and the number of TSCs varied with topography. Although there was no significant difference due to the small sample size, the number of pseudopodia and cell polarizability still showed differences among different topographies. The morphology of actin cytoskeleton of TSCs showed difference among cultured on porous fibers, smooth fibers, and in culture media with no fiber, suggesting the orientation growth of cells on porous fiber. Moreover, porous fibers promoted teno-lineage differentiation of TSCs by upregulating tendon-specific gene expression. These findings provide evidence that nano porous topography scaffold promotes TSC proliferation, cytoskeleton orientation, and tenogenic differentiation.
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Glicerol , Nanoporos , Tendones , Células Madre , Ingeniería de Tejidos , Diferenciación Celular , Proliferación CelularRESUMEN
Cross-domain object detection is a key problem in the research of intelligent detection models. Different from lots of improved algorithms based on two-stage detection models, we try another way. A simple and efficient one-stage model is introduced in this paper, comprehensively considering the inference efficiency and detection precision, and expanding the scope of undertaking cross-domain object detection problems. We name this gradient reverse layer-based model YOLO-G, which greatly improves the object detection precision in cross-domain scenarios. Specifically, we add a feature alignment branch following the backbone, where the gradient reverse layer and a classifier are attached. With only a small increase in computational, the performance is higher enhanced. Experiments such as CityscapesâFoggy Cityscapes, SIM10kâCityscape, PASCAL VOCâClipart, and so on, indicate that compared with most state-of-the-art (SOTA) algorithms, the proposed model achieves much better mean Average Precision (mAP). Furthermore, ablation experiments were also performed on 4 components to confirm the reliability of the model. The project is available at https://github.com/airy975924806/yolo-G.
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Algoritmos , Inteligencia , Reproducibilidad de los ResultadosRESUMEN
Al2O3-bonded SiAlON ceramic with self-coating was prepared using aluminum dross and silicon solid waste as starting materials under ambient air conditions. The changes in phase, microstructure, and physical properties of the ceramic with temperature were analyzed and the formation mechanism of the SiAlON phase was elucidated. The results showed that higher temperature was more suitable for the preparation of SiAlON ceramics. As the temperature increased from 1400 to 1600 °C, the main phases in the ceramic transformed from mullite, Al2O3, and SiAlON to Al2O3 and SiAlON. An Al2O3-rich layer spontaneously coated the surface of the porous ceramic as Al melted and oxidized at high temperature. The thickness of this layer decreased as the temperature increased. The presence of Al2O3-rich coating layer impeded air flow, allowing nitriding of Si and Al, and the formation of the SiAlON phase in ambient air conditions. This study not only presents a strategy to successfully recycle aluminum dross and silicon solid waste but also offers a straightforward approach to preparing SiAlON material in air atmosphere.
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The mechanical properties of a stem cell culture substrate significantly impact cell adhesion, survival, migration, proliferation, and differentiation in vitro. A major challenge in engineering artificial stem cell substrate is to properly identify the relevant physical features of native stem cell niches, which are likely different for each stem cell type. The behavior of tendon stem cells has potentially significant implications for tendon repair. Here, microfiber scaffolds with various modulus of elasticity are fabricated by near-field electrospinning, and their regulating effects on the in vitro behavior of tendon stem cells (TSCs) are discussed in this study. The number of pseudopodia shows a biphasic relationship with the modulus of scaffold. The proliferation, polarization ratio and alignment degree along the fibers of the TSCs increase with the increase of fiber modulus. TSCs cultured on the scaffold with moderate modulus (1429 MPa) show the upregulation of tendon-specific genes (Col-I, Tnmd, SCX and TNCF). These microfiber scaffolds provide great opportunities to modulate TSCs behavior at the micrometer scales. In conclusion, this study provides an instructive mechanical microenvironment for TSCs behaviors and may lead to the development of desirable engineered artificial stem cell substrate for tendon healing.
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Ingeniería de Tejidos , Andamios del Tejido , Andamios del Tejido/química , Tendones , Células Madre , Diferenciación Celular/genética , Expresión Génica , Proliferación Celular , Regulación de la Expresión GénicaRESUMEN
Multiphase oxidative aging is a ubiquitous process for atmospheric organic aerosols (OA). But its kinetics was often found to be slow in previous laboratory studies where high hydroxyl radical concentrations ([â¢OH]) were used. In this study, we performed heterogeneous oxidation experiments of several model OA systems under varied aging timescales and gas-phase [â¢OH]. Our results suggest that OA heterogeneous oxidation may be 2-3 orders of magnitude faster when [â¢OH] is decreased from typical laboratory flow tube conditions to atmospheric levels. Direct laboratory mass spectrometry measurements coupled with kinetic simulations suggest that an intermolecular autoxidation mechanism mediated by particle-phase peroxy radicals greatly accelerates OA oxidation, with enhanced formation of organic hydroperoxides, alcohols, and fragmentation products. With autoxidation, we estimate that the OA oxidation timescale in the atmosphere may be from less than a day to several days. Thus, OA oxidative aging can have greater atmospheric impacts than previously expected. Furthermore, our findings reveal the nature of heterogeneous aerosol oxidation chemistry in the atmosphere and help improve the understanding and prediction of atmospheric OA aging and composition evolution.
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Atmósfera , Atmósfera/análisis , Atmósfera/química , Aerosoles/análisis , Oxidación-ReducciónRESUMEN
In this research, a new composite adsorbent (SC@ZVI@CS-AA) was designed and synthesized, and its application for the removal of Cr(VI) in groundwater was investigated. The interaction between SC@ZVI@CS-AA and Cr(VI) conformed to a pseudo-second-order model, and the adsorption process was dominated by chemisorption. The effects of material ratios, pH, temperature, SC@ZVI@CS-AA dosage, and coexisting ions on the removal of Cr(VI) were investigated. The removal efficiency of Cr(VI) by SC@ZVI@CS-AA reached 95%, and the reaction was significantly inhibited when SO42- was present. Thermodynamically, the adsorption of Cr(VI) proceeded spontaneously above 35 °C (ΔGθ < 0). According to scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometry, and synchronous thermal analysis, the removal mechanism of Cr(VI) by SC@ZVI@CS-AA was attributed to electrostatic attraction and reduction. In addition, SC@ZVI@CS-AA had good cyclic adsorption performance. Overall, the SC@ZVI@CS-AA composite showed great potential in the remediation of Cr(VI)-contaminated groundwater.
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Quitosano , Agua Subterránea , Contaminantes Químicos del Agua , Quitosano/química , Contaminantes Químicos del Agua/análisis , Hierro/química , Cromo/química , Agua Subterránea/química , AdsorciónRESUMEN
Unmanned ground vehicles (UGVs) are making more and more progress in many application scenarios in recent years, such as exploring unknown wild terrain, working in precision agriculture and serving in emergency rescue. Due to the complex ground conditions and changeable surroundings of these unstructured environments, it is challenging for these UGVs to obtain robust and accurate state estimations by using sensor fusion odometry without prior perception and optimization for specific scenarios. In this paper, based on an error-state Kalman filter (ESKF) fusion model, we propose a robust lidar-inertial odometry with a novel ground condition perception and optimization algorithm specifically designed for UGVs. The probability distribution gained from the raw inertial measurement unit (IMU) measurements during a certain time period and the state estimation of ESKF were both utilized to evaluate the flatness of ground conditions in real-time; then, by analyzing the relationship between the current ground condition and the accuracy of the state estimation, the tightly coupled lidar-inertial odometry was dynamically optimized further by adjusting the related parameters of the processing algorithm of the lidar points to obtain robust and accurate ego-motion state estimations of UGVs. The method was validated in various types of environments with changeable ground conditions, and the robustness and accuracy are shown through the consistent accurate state estimation in different ground conditions compared with the state-of-art lidar-inertial odometry systems.
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Algoritmos , Percepción , Movimiento (Física) , Probabilidad , Factores de TiempoRESUMEN
Limonene is an abundant monoterpene released into the atmosphere via biogenic emissions and biomass burning. However, the atmospheric oxidation and secondary organic aerosol (SOA) formation mechanisms of limonene, especially during nighttime, remain largely understudied. In this work, limonene was oxidized synergistically by ozone (O3) and nitrate radicals (NO3) in a flow tube reactor and a continuous flow stirred tank reactor. Upon oxidation, many highly oxidized organic nitrates and nitrooxy peroxy radicals (RO2) were observed in the gas phase within 1 min. Combining quantum chemical calculations with kinetic simulations, we found that the primary nitrooxy RO2 (C10H16NO5) through NO3 addition at the more substituted endocyclic double bond and at the exocyclic double bond (previously considered as minor pathways) can undergo autoxidation with rate constants of around 0.02 and 20 s-1 at 298 K, respectively. These pathways could explain a major portion of the observed highly oxidized organic nitrates. In the SOA, highly oxidized mono- and dinitrates (e.g., C10H17NO7-8 and C10H16,18N2O8-10) make up a significant contribution, highlighting nitrooxy RO2 autoxidation and sequential NO3 oxidation of limonene. The same organic nitrates are also observed in ambient aerosol during biomass burning and nighttime in the southeastern United States. Therefore, the present work provides new insights into the nighttime oxidation of limonene and SOA formation in the atmosphere.