4-(4-Cyano-2-fluoro­phen­oxy)phenyl 4-methyl­benzene­sulfonate

The title compound, C20H14FNO4S, was synthesized from hydro­quinone, p-toluene­sulfonyl chloride and 3,4-difluoro­benzonitrile. A folded conformation is adopted by the crystal structure. Inter­molecular C—H⋯N hydrogen bonds form dimers arranged around inversion centers

Experimental study on the emission characteristic of a methanol engine based on transient cycle WHTC

The emission characteristics of regulated emissions and unregulated emissions were studied under the full loads and the cold/hot transient cycle (WHTC) on a six-cylinder, multi-point injection, and spark ignition methanol engine. The results show that the emissions of THC and CO for the methanol engine is at a high level without three-way catalyst (TWC) and the emission of NOX could be controlled at a lower level than 400 mg/kW·h with exhaust gas recirculation (EGR). The emissions of THC, CO and NOX are low with TWC, whose weighted results under WHTC could be kept at a lower level than the limits in China VI Standard. It is a technical difficulty to control the emissions of methanol (CH3OH) and formaldehyde (HCHO) for methanol engines, especially under the cold WHTC, there has a high risk for the emission of CH3OH exceeding the limit of standard

Experimental study on the factors influencing performance and emissions of hydrogen internal combustion engines

Hydrogen internal combustion engines (H2-ICEs) have advantages such as clean combustion and zero carbon emissions, and have become one of the important technical routes for decarbonization in the internal combustion engine industry. In this paper, several key factors affecting the performance and emissions of hydrogen internal combustion engines, such as ignition timing, excess air coefficient, and hydrogen injection timing, were systematically studied on a spark ignition multi-point injection (MPI) hydrogen internal combustion engine bench. The experimental results indicate that the ignition timing controls the combustion phase of hydrogen. Moderate early ignition can improve the brake thermal efficiency (BTE) while having little impact on the NOX emissions. Excess air coefficient(λ) can significantly affect the performance and emissions of H2-ICE. Along with the increase of the λ, the NOX emissions first increases and then continues to decline. When the λ reaching 2.1 or above, near zero emissions of NOX can be achieved. The advance of hydrogen injection timing will slightly increase the peak of cylinder pressure and instantaneous heat release rate. However, overall, the impact of hydrogen injection timing on BTE and NOX emissions is not significant on MPI H2-ICE

Effect of diesel detergent synergists on VOCs emissions from engine

In this study, the volatile organic compounds (VOCs) emissions from engine fueled diesel with and without detergent synergist were measured by gas chromatography mass spectrometry(GC-MS). The test results show that compared with reference diesel fuel (without diesel detergent synergist), the use of different diesel detergent synergists has different effects on the VOCs emissions while without after-treatment device. Whether with or without after-treatment device, alkanes always account for the highest proportion of VOCs emissions while engine fuels with different diesel detergent synergists. After-treatment device diesel oxidation catalyst coupled with diesel particulate filter (DOC+DPF) has high catalytic efficiency for VOCs emissions from engine fueled with different fuels, and most of the catalytic efficiency could reach more than 95%. With the catalytic treatment of after-treatment device,the concentrations of carcinogens (detected in this study) in VOCs emissions from engine fueled with and without detergent synergist are far lower than that specified in reference standard GBZ 2.1-2007 “Occupational Exposure Limits for Hazardous Factors in the Workplace and Chemical Hazardous Factors”, respectively. The test results indicate that the use of diesel detergent synergist will not have an adverse impact on human health and it can be safely used

Identification and validation of potential diagnostic signature and immune cell infiltration for NAFLD based on cuproptosis-related genes by bioinformatics analysis and machine learning

Background and aimsCuproptosis has been identified as a key player in the development of several diseases. In this study, we investigate the potential role of cuproptosis-related genes in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).MethodThe gene expression profiles of NAFLD were obtained from the Gene Expression Omnibus database. Differential expression of cuproptosis-related genes (CRGs) were determined between NAFLD and normal tissues. Protein–protein interaction, correlation, and function enrichment analyses were performed. Machine learning was used to identify hub genes. Immune infiltration was analyzed in both NAFLD patients and controls. Quantitative real-time PCR was employed to validate the expression of hub genes.ResultsFour datasets containing 115 NAFLD and 106 control samples were included for bioinformatics analysis. Three hub CRGs (NFE2L2, DLD, and POLD1) were identified through the intersection of three machine learning algorithms. The receiver operating characteristic curve was plotted based on these three marker genes, and the area under the curve (AUC) value was 0.704. In the external GSE135251 dataset, the AUC value of the three key genes was as high as 0.970. Further nomogram, decision curve, calibration curve analyses also confirmed the diagnostic predictive efficacy. Gene set enrichment analysis and gene set variation analysis showed these three marker genes involved in multiple pathways that are related to the progression of NAFLD. CIBERSORT and single-sample gene set enrichment analysis indicated that their expression levels in macrophages, mast cells, NK cells, Treg cells, resting dendritic cells, and tumor-infiltrating lymphocytes were higher in NAFLD compared with control liver samples. The ceRNA network demonstrated a complex regulatory relationship between the three hub genes. The mRNA level of these hub genes were further confirmed in a mouse NAFLD liver samples.ConclusionOur study comprehensively demonstrated the relationship between NAFLD and cuproptosis, developed a promising diagnostic model, and provided potential targets for NAFLD treatment and new insights for exploring the mechanism for NAFLD

Epidemiology of atrial fibrillation and risk of CVD mortality among hypertensive population: A prospective cohort study in Northeast China

BackgroundDetermining risk factors of cardiovascular disease (CVD)-related mortality and evaluating their influence are important for effectively reducing corresponding mortality. However, few research findings have estimated the relationship between atrial fibrillation (AF) and CVD-related mortality among hypertension individuals.ObjectiveThe objective of this study was to investigate the epidemiology of AF in a hypertension population and determine the relationship between AF and CVD-related mortality.MethodsUsing a multistage, stratified, and cluster random sampling method, the prospective cohort study with a median follow-up of 3.51 years enrolled 10,678 hypertensive participants at baseline. The prevalence, awareness, and anticoagulation data of AF in this focal population were carefully assessed. Stepwise logistic regression and Cox regression analysis were respectively performed to evaluate the determinants of AF and the association between AF and CVD-related mortality.ResultsThe overall prevalence of AF was 1.3% (95% CI, 1.1%−1.6%) in the hypertensive population, and it was higher in men than in women (1.8% vs. 1.0%, respectively; p=0.001). The awareness of AF was 53.1%, and the rate of oral anticoagulant (OAC) therapy was only 4.2%, although all AF participants should have required according to the European Society of Cardiology guidelines. The determinants of AF included elder, male, and history of coronary heart disease in the hypertensive population. Besides, compared with individuals without AF, the risk of CVD-related mortality significantly increased in the hypertensive population with AF (HR 3.37, 95% CI 2.10–5.40).ConclusionOur results indicated a huge burden of AF and underuse of OAC therapy for them in a community-based hypertensive population. Considering that most of the risk factors of AF were unmodifiable in hypertensive individuals, as well as its high risk of mortality, long-term interventions including AF education, timely screening, and widespread use of OACs should be emphasized in the focal populations

Instantaneous one-dimensional ammonia measurements with femtosecond two-photon laser-induced fluorescence (fs-TPLIF)

Ammonia (NH3) has been identified as a potential hydrogen-carrier fuel with no carbon emissions. Non-intrusive in-situ NH3 diagnostic technique is of great interest. In this work, femtosecond two-photon laser-induced fluorescence (fs-TPLIF) was demonstrated in NH3/N2 mixtures to achieve NH3 measurements. A femtosecond laser at 305 nm was used for two-photon excitation of NH3 to its excited state (X–C′), and the subsequent fluorescence at ~565 nm from transition C′-A was detected. In addition, a detection limit of 730 ppm was achieved in NH3/N2 mixtures. Furthermore, one-dimensional single-shot images of NH3 were obtained in both laminar and turbulent flow fields. This work is the first attempt of fs-TPLIF for polyatomic molecular gases measurements, and the obtained results indicate that fs-TPLIF could be a promising tool for NH3 measurements

Ammonia measurements with femtosecond laser-induced plasma spectroscopy

Femtosecond laser-induced plasma spectroscopy for in situ ammonia (NH 3 ) measurements was demonstrated in NH 3 ∕N 2 mixtures. When a femtosecond laser at 800 nm was focused at the flow field, the parent NH 3 molecules would be photolyzed to generate electronics excited NH fragments, and then indirect measurements of NH 3 could be realized by detecting the NH fluorescence (A 3 Π − X 3 Σ − ) at 336 nm. A detection limit of 205 ppm was achieved. This work is the first attempt, to the best of our knowledge, for ammonia measurements with a femtosecond laser, and the results are useful for the development of ammonia diagnostics

A new improved fruit fly optimization algorithm IAFOA and its application to solve engineering optimization problems

Nature-inspired algorithms are widely used in mathematical and engineering optimization. As one of the latest swarm intelligence-based methods, fruit fly optimization algorithm (FOA) was proposed inspired by the foraging behavior of fruit fly. In order to overcome the shortcomings of original FOA, a new improved fruit fly optimization algorithm called IAFOA is presented in this paper. Compared with original FOA, IAFOA includes four extra mechanisms: 1) adaptive selection mechanism for the search direction, 2) adaptive adjustment mechanism for the iteration step value, 3) adaptive crossover and mutation mechanism, and 4) multi-sub-swarm mechanism. The adaptive selection mechanism for the search direction allows the individuals to search for global optimum based on the experience of the previous iteration generations. According to the adaptive adjustment mechanism, the iteration step value can change automatically based on the iteration number and the best smell concentrations of different generations. Besides, the adaptive crossover and mutation mechanism introduces crossover and mutation operations into IAFOA, and advises that the individuals with different fitness values should be operated with different crossover and mutation probabilities. The multi-sub-swarm mechanism can spread optimization information among the individuals of the two sub-swarms, and quicken the convergence speed. In order to take an insight into the proposed IAFOA, computational complexity analysis and convergence analysis are given. Experiment results based on a group of 29 benchmark functions show that IAFOA has the best performance among several intelligent algorithms, which include five variants of FOA and five advanced intelligent optimization algorithms. Then, IAFOA is used to solve three engineering optimization problems for the purpose of verifying its practicability, and experiment results show that IAFOA can generate the best solutions compared with other ten algorithms

A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics

The applications of femtosecond lasers to the diagnostics of combustion and flow field have recently attracted increasing interest. Many novel spectroscopic methods have been developed in obtaining non-intrusive measurements of temperature, velocity, and species concentrations with unprecedented possibilities. In this paper, several applications of femtosecond-laser-based incoherent techniques in the field of combustion diagnostics were reviewed, including two-photon femtosecond laser-induced fluorescence (fs-TPLIF), femtosecond laser-induced breakdown spectroscopy (fs-LIBS), filament-induced nonlinear spectroscopy (FINS), femtosecond laser-induced plasma spectroscopy (FLIPS), femtosecond laser electronic excitation tagging velocimetry (FLEET), femtosecond laser-induced cyano chemiluminescence (FLICC), and filamentary anemometry using femtosecond laser-extended electric discharge (FALED). Furthermore, prospects of the femtosecond-laser-based combustion diagnostic techniques in the future were analyzed and discussed to provide a reference for the relevant researchers