High-mobility graphene on liquid p-block elements by ultra-low-loss CVD growth

The high-quality and low-cost of the graphene preparation method decide whether graphene is put into the applications finally. Enormous efforts have been devoted to understand and optimize the CVD process of graphene over various d-block transition metals (e.g. Cu, Ni and Pt). Here we report the growth of uniform high-quality single-layer, single-crystalline graphene flakes and their continuous films over p-block elements (e.g. Ga) liquid films using ambient-pressure chemical vapor deposition. The graphene shows high crystalline quality with electron mobility reaching levels as high as 7400 cm2 V−1s−1 under ambient conditions. Our employed growth strategy is ultra-low-loss. Only trace amounts of Ga are consumed in the production and transfer of the graphene and expensive film deposition or vacuum systems are not needed. We believe that our research will open up new territory in the field of graphene growth and thus promote its practical application

Unraveling the microbial puzzle: exploring the intricate role of gut microbiota in endometriosis pathogenesis

Endometriosis (EMs) is a prevalent gynecological disorder characterized by the growth of uterine tissue outside the uterine cavity, causing debilitating symptoms and infertility. Despite its prevalence, the exact mechanisms behind EMs development remain incompletely understood. This article presents a comprehensive overview of the relationship between gut microbiota imbalance and EMs pathogenesis. Recent research indicates that gut microbiota plays a pivotal role in various aspects of EMs, including immune regulation, generation of inflammatory factors, angiopoietin release, hormonal regulation, and endotoxin production. Dysbiosis of gut microbiota can disrupt immune responses, leading to inflammation and impaired immune clearance of endometrial fragments, resulting in the development of endometriotic lesions. The dysregulated microbiota can contribute to the release of lipopolysaccharide (LPS), triggering chronic inflammation and promoting ectopic endometrial adhesion, invasion, and angiogenesis. Furthermore, gut microbiota involvement in estrogen metabolism affects estrogen levels, which are directly related to EMs development. The review also highlights the potential of gut microbiota as a diagnostic tool and therapeutic target for EMs. Interventions such as fecal microbiota transplantation (FMT) and the use of gut microbiota preparations have demonstrated promising effects in reducing EMs symptoms. Despite the progress made, further research is needed to unravel the intricate interactions between gut microbiota and EMs, paving the way for more effective prevention and treatment strategies for this challenging condition

Room-temperature conversion of ethane and the mechanism understanding over single iron atoms confined in graphene

Abstract(#br)The catalytic conversion of ethane to high value-added chemicals is significantly important for utilization of hydrocarbon resources. However, it is a great challenge due to the typically required high temperature (> 400 °C) conditions. Herein, a highly active catalytic conversion process of ethane at room temperature (25 °C) is reported on single iron atoms confined in graphene via the porphyrin-like N 4 -coordination structures. Combining with the operando time of flight mass spectrometer and density functional theory calculations, the reaction is identified as a radical mechanism, in which the C–H bonds of the same C atom are preferentially and sequentially activated, generating the value-added C 2 chemicals, simultaneously avoiding the over-oxidation of the products to CO 2 . The in-situ formed O–FeN 4 –O structure at the single iron atom serves as the active center for the reaction and facilitates the formation of ethyl radicals. This work deepens the understanding of alkane C–H activation on the FeN 4 center and provides the reference in development of efficient catalyst for selective oxidation of light alkane

Microbial Community Succession and Response to Environmental Variables During Cow Manure and Corn Straw Composting

In composting system, the composition of microbial communities is determined by the constant change in the physicochemical parameters. This study explored the dynamics of bacterial and fungal communities during cow manure and corn straw composting using high throughput sequencing technology. The relationships between physicochemical parameters and microbial community composition and abundance were also evaluated. The sequencing results revealed the major phyla included Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi and Actinobacteria, Ascomycota, and Basidiomycota. Linear discriminant analysis effect size (LEfSe) illustrated that Actinomycetales and Sordariomycetes were the indicators of bacteria and fungi in the maturation phase, respectively. Mantel test showed that NO3--N, NH4+-N, TN, C/N, temperature and moisture content significantly influenced bacterial community composition while only TN and moisture content had a significant effect on fungal community structure. Structural equation model (SEM) indicated that TN, NH4+-N, NO3--N and pH had a significant effect on fungal abundance while TN and temperature significantly affected bacterial abundance. Our finding increases the understanding of microbial community succession in cow manure and corn straw composting under natural conditions

Unraveling the mechanisms of NK cell dysfunction in aging and Alzheimer’s disease: insights from GWAS and single-cell transcriptomics

BackgroundAging is an important factor in the development of Alzheimer’s disease (AD). The senescent cells can be recognized and removed by NK cells. However, NK cell function is gradually inactivated with age. Therefore, this study used senescence as an entry point to investigate how NK cells affect AD.MethodsThe study validated the correlation between cognition and aging through a prospective cohort of the National Health and Nutrition Examination Survey database. A cellular trajectory analysis of the aging population was performed using single-cell nuclear transcriptome sequencing data from patients with AD and different ages. The genome-wide association study (GWAS) cohort of AD patients was used as the outcome event, and the expression quantitative trait locus was used as an instrumental variable. Causal associations between genes and AD were analyzed by bidirectional Mendelian randomization (MR) and co-localization. Finally, clinical cohorts were constructed to validate the expression of key genes.ResultsA correlation between cognition and aging was demonstrated using 2,171 older adults over 60 years of age. Gene regulation analysis revealed that most of the highly active transcription factors were concentrated in the NK cell subpopulation of AD. NK cell trajectories were constructed for different age populations. MR and co-localization analyses revealed that CHD6 may be one of the factors influencing AD.ConclusionWe explored different levels of AD and aging from population cohorts, single-cell data, and GWAS cohorts and found that there may be some correlations of NK cells between aging and AD. It also provides some basis for potential causation

An Overview of Chassis Dynamometer in the Testing of Vehicle Emission

Air pollution is a risk to health and the vehicle emission is becoming a serious cause of the air pollution. Vehicle emission is influenced by many factors. The measurement of the vehicle emission can be achieved by the chassis dynamometer which can simulate the driving on the real road. The chassis-dynamometer-based testing can provide a repeatable experiment and precise emission evaluation under various driving condition. In this paper, we review the testing of vehicle emission based on a chassis dynamometer. The investigation results manifest that advance testing method for achieving the real-world driving resistance should be studied and better data analysis method should be proposed to get a more reasonable driving cycle

A Study on Finite Element Analysis of Electric Bus Frame for Lightweight Design

The air pollution becomes a risk to health with the increasingly growing of car ownership in China. Due to the increase of energy crisis and environmental pollutant, the electric vehicle is becoming a promising transport in the urban area. However, the drawback of the electric vehicle lies in the endurance of the vehicle battery. Therefore, the lightweight design which adopts both the structural steel and the aluminum alloy can reduce the weight of the vehicle body extending the battery life between charges. In this paper, we used a finite element analysis (FEA) method for the lightweight optimization of the electric bus frame. Four driving condition (full load bending condition, torsional condition, emergency braking and emergency steering) were considered for the analysis. By changing the structure of bus frame, the weight of the bus reduced while the mechanical property improved under the adopted driving condition

Research on the effect of micro-voids on the deformation behavior and crack initiation lifetime of titanium alloy under cyclic loading by crystal plasticity finite element method

Micro-voids defects associated with materials formed by diffusion bonding and super-plastic connection limit their usage in the aerospace industry. A crystal plasticity finite element (CPFE) model was established in the current work to investigate the relationship between local stress concentration and the micro-void defects, and predict the fatigue crack initiation lifetime. Based on the concept of the curvature of the crack tip, the shape and size of the voids are strictly separated, so that the influence of the single parameter of voids on the microplasticity deformation behavior is better obtained. It's found that the micro-voids lead to the stress concentration phenomenon in the material, the effect of the curvature of the void tip surface is greater than that of the void size. Stress concentration tends to occur in the hard grains. When L/d is greater than 2.0, stress concentration factor reaches a constant small value. The simulated results based on the Manson-Collin law and Fatemi-Socie parameter show that when the void tip curvature is greater than 0.4 μm−1 or L/d is less than 2.0, the fatigue crack initiation lifetime is less than 106 cycles, indicating that the influence of such micro-voids on fatigue crack initiation is small. This work has a good guiding significance for properties and lifetime prediction of the material with defects

A Subnano-g Electrostatic Force-Rebalanced Flexure Accelerometer for Gravity Gradient Instruments

A subnano-g electrostatic force-rebalanced flexure accelerometer is designed for the rotating accelerometer gravity gradient instrument. This accelerometer has a large proof mass, which is supported inversely by two pairs of parallel leaf springs and is centered between two fixed capacitor plates. This novel design enables the proof mass to move exactly along the sensitive direction and exhibits a high rejection ratio at its cross-axis directions. Benefiting from large proof mass, high vacuum packaging, and air-tight sealing, the thermal Brownian noise of the accelerometer is lowered down to less than 0.2 ng / Hz with a quality factor of 15 and a natural resonant frequency of about 7.4 Hz . The accelerometer’s designed measurement range is about ±1 mg. Based on the correlation analysis between a commercial triaxial seismometer and our accelerometer, the demonstrated self-noise of our accelerometers is reduced to lower than 0.3 ng / Hz over the frequency ranging from 0.2 to 2 Hz, which meets the requirement of the rotating accelerometer gravity gradiometer

Improving the Shape Memory Effect of a Fe-Mn-Si-Cr-Ni Alloy through Shot Peening

To improve the shape memory effect, the solutionized Fe-24Mn-6Si-9Cr-6Ni alloy was shot peened and subsequently annealed. The phase constituent was examined using the X-ray diffraction method. Microstructure evolution was characterized using an optical microscope and the electronic backscatter diffraction method, and the shape memory effect was evaluated using a bending test. The results show that α′-martensite and ε-martensite were introduced into the shot-peened surface layer. The α′-martensite remained after annealing even at 850 °C. Microstructure of the surface layer was refined through shot peening and subsequent annealing. Compared with those of the solutionized specimen, the shape recovery ratio and recovery strain of the specimens that are shot peened and subsequently annealed are significantly improved at different prestrains