With the continuous growth of economy, we are more and more aware of the importance of energy and its preciousness. In the production of crude oil, the narrow channel is the best location for oil ...storage, and the underlying sand body often has oil resources. In this paper, the effect of reservoir polymer flooding is taken as the purpose, the principle of polymer flooding technology as the theoretical basis, through the analysis of dynamic change characteristics, in order to improve the adjustment parameters, to achieve reasonable and efficient exploitation of oil Wells. The application of this technology, through the development of practice, has been recognized as an effective method of oil recovery.
Phthalates (phthalic acid esters) have been widely applied as plasticizers. They are ubiquitous contaminants in soils, thereby posing a threat to human health. In this study, ecotoxicological effects ...of three typical PAEs (dimethyl phthalate-DMP, di-n-octyl phthalate-DOP and butyl benzyl phthalate-BBP) were investigated. As a biological indicator, earthworms (Eisenia fetida) were exposed to phthalates at various doses (0, 0.1, 1, 10 and 50 mg/kg) for different times (7, 14, 21, and 28 d). We evaluated the effects of phthalates on reactive oxygen species (ROS) generation, antioxidant enzymes (superoxide dismutase-SOD, peroxidase-POD and catalase-CAT) activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that ROS content increased with increasing phthalates, whereas ROS content generally increased and then decreased with exposure time. However, antioxidant enzymes activities in earthworms displayed different trends. The GST activity in high-dose treatment group was significantly activated. For DMP and DOP, lipid peroxidation mainly occurred between 14 and 28 d, while for BBP, it primarily existed after 7 d and then disappeared after 28 d. Besides, comet assay indicated that there was a dose-response relationship between the DNA damage and phthalate dose, following DMP > DOP > BBP. Given their toxicity, it is important to understand the mechanisms associated with their eco-toxicity and to reduce their adverse impacts on the environment.
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•Phthalates induced oxidative stress and DNA damage in earthworms.•Phthalates enhanced ROS generation and lipid peroxidation, and activated GST.•Different antioxidant enzymes responded differently to DMP, DOP and BBP.•Phthalate-generated DNA damage followed DMP > DOP > BBP.
Livestock manure is a major reservoir of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study investigated the distribution characteristics of ARB, ARGs in fresh and ...composted manures of traditional breading industry in rural areas in China. Samples collected were naturally piled without professional composting, and will be applied to farmland. The real-time quantitative polymerase chain reaction (qPCR) results showed the presence of ten target ARGs and two mobile genetic elements (MGEs) in the tested manure samples. The relative abundance of tetracycline and sulfonamide resistance genes (TRGs and SRGs) was generally higher than that of macrolide resistance genes (MRGs), followed by quinolone resistance genes (QRGs). There were significant positive correlations between the abundance of sul1, sul2, tetW and MGEs (intl1, intl2). In addition, the distribution of target ARGs was associated with the residual concentrations of doxycycline (DOX), sulfamethazine (SM2), enrofloxacin (ENR) and tylosin (TYL). Overall, a total of 24 bacterial genera were identified. The resistance rates of ARB were 17.79%–83.70% for SM2, followed 0.40%–63.77% for TYL, 0.36%–43.90% for DOX and 0.00%–13.36% for ENR, which showed a significant dose-effect. This study also demonstrated that the abundance of clinically relevant ARB and ARGs in chicken, swine and cow fresh manures significantly greater than that in composted manures, and chicken and swine manures had higher proportion of ARB and higher abundance of ARGs than that in cow manures.
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•Chicken and swine manures have higher abundance of ARB and ARGs than cow manures.•The abundance of ARB and ARGs in fresh manures was significantly higher than that in composted manures.•Detected antibiotics and MGEs were significantly correlated with some of the target ARGs.•Acinetobacter lwoffii and Psychrobacter pulmonis are multiple resistant bacteria.
Simultaneous imaging and treatment of infections remains a major challenge, with most current approaches being effective against only one specific group of bacteria or not being useful for diagnosis. ...Here we develop multifunctional nanoagents that can potentially be used for imaging and treatment of infections caused by diverse bacterial pathogens. The nanoagents are made of fluorescent silicon nanoparticles (SiNPs) functionalized with a glucose polymer (e.g., poly4-O-(α-D-glucopyranosyl)-D-glucopyranose) and loaded with chlorin e6 (Ce6). They are rapidly internalized into Gram-negative and Gram-positive bacteria by a mechanism dependent on an ATP-binding cassette (ABC) transporter pathway. The nanoagents can be used for imaging bacteria by tracking the green fluorescence of SiNPs and the red fluorescence of Ce6, allowing in vivo detection of as few as 10
colony-forming units. The nanoagents exhibit in vivo photodynamic antibacterial efficiencies of 98% against Staphylococcus aureus and 96% against Pseudomonas aeruginosa under 660 nm irradiation.
Heavy metals pollution of soil and widespread application of neonicotinoid insecticides have caused environmental problems worldwide. To evaluate ecological toxicity resulting from the combined ...pollution of neonicotinoids and heavy metals, typical representatives of neonicotinoid insecticides (imidacloprid, thiamethoxam, dinotefuran) and heavy metals (cadmium, copper, zinc) were selected as soil pollutants; earthworms were used as test organisms. Analysis of the main and interaction effects of a combined pollution process were performed using a uniform design method. Results showed that the reactive oxygen species (ROS) content of earthworms in most treatment groups was higher during exposure than that of the control group. The malondialdehyde (MDA) and ROS content of earthworms demonstrated relatively low values on the 21st day and increased by the 28th day. The interaction between dinotefuran and Cd had significant antagonistic effects on ROS and MDA. The combined pollution adversely affected both the growth and genes of earthworms and also caused damage to the epidermis, midgut, and DNA. The interaction between imidacloprid and Cd was synergistic to ROS, weight inhibition rate, and Olive tail moment (OTM), but was antagonistic to MDA. Of all the single and combined exposures, Zn as a single chemical affected ROS and DNA damage the most, and MDA was significantly enhanced by imidacloprid. Composite pollutants may create different primary effects and interactions causing potential harm to soil organisms.
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•Combined pollution caused oxidative stress and damage to the growth, tissue, and DNA in earthworms.•Analysis of the main and interaction effects of a combined pollution process were performed using a uniform design method.•ROS, MDA, weight inhibition rate, and OTM of earthworms were all affected by the interaction between imidacloprid and Cd.•Excessive ROS and MDA likely caused damage to the epidermis, midgut, and DNA of earthworms.
Experimental study on the self-acceleration characteristics and laminar flame speed of CO/H2/air mixtures was conducted at elevated pressures up to 0.6 MPa with spherical outwardly expanding flames. ...Experimental conditions for the CO/H2/air mixtures of hydrogen fraction in syngas from 0.2 to 0.8, the pressures from 0.4 to 0.6 MPa and equivalence ratios from 0.5 to 1.0. At elevated pressures, the cellular structure occurs on the early stage of the flame development due to the significant influences of thermal diffusive and hydrodynamic instabilities and flame front was accelerated. Critical radius after which flame front becomes unstable decreases with H2 content in the fuel mixtures. For syngas mixtures with higher H2 content, critical radius increases with the increase of the equivalence ratio. Critical radius decreases with the increase of the equivalence ratio for the mixture with lower H2 content. Critical Peclet number, which is defined as the ratio of critical radius to flame thickness increases firstly and then decreases with H2 content for the mixtures with higher equivalence ratios and decreases all the time for the mixture with lower ones. In addition, the acceleration exponent which indicates the acceleration characteristics when flame front becomes unstable increases with the flame front propagation and is not the same with that of the turbulent flame. At last, an updated method, which excludes the acceleration effect of the cellular structure on the stretched flame speed at various flame radii has been proposed. It will help to obtain the laminar flame speed for fuel/air mixtures at elevated pressures with small time region between the end of the ignition spark and the onset of flame instability. This updated model replaces the experimental determined exponential term of the fractal structure and the updated intrinsic flame instability model. The measured laminar flame speed data are compared and analyzed with those predicted by Davis and Li mechanisms of syngas.
•Critical radius and Peclet number of syngas/air mixture at elevated pressure is obtained.•Acceleration characteristics when flame front becomes unstable is studied.•Effect of the intrinsic flame instability on the stretched flame speed is investigated.•Method to evaluate the laminar flame speed at elevated pressures is developed.
•The emission of CH4/NH3/air flames in a swirl combustor are investigated.•The emission of ammonia ratio from 0 to 1.0 are investigated experimentally.•Two chemical reactions are identified as the ...major reactions to produce NO and NO2.•The chemical reactor networks are performed to reveal the pathways of NOx production.
Ammonia is regarded as one of the potential hydrogen carriers and a kind of carbon-free renewable energy source. However, there are still some challenges on ammonia application in combustion devices, i.e., the high NOX emission. In this study, the combustion performances and emission characteristics of co-firing CH4/NH3/air flame with NH3 mole fraction (ηNH3) from 0 to 1.0 are investigated in a swirl combustor. The emissions in the exhaust gas are analyzed by the Gasmet DX4000 Fourier Transform Infrared (FTIR) gas analyzer. The simulations of the chemical reactor networks (CRN) with a detailed mechanism are employed to extend the understanding of experimental data. Results show that the combustion efficiency is very low at fuel lean conditions for high ηNH3 flames, and NOX emission significantly increases when blending a small amount of ammonia. The co-firing flames produce large amount of NOx at lean conditions (ϕ less than 1.0). There exits an optimized condition (ϕ≈1.1) where the NOx and NH3 emissions reach their lowest value simultaneously. The co-firing flame produces maximum NOx emission at ηNH3 = 0.5. Therefore, to control the NOX emission, the CH4/NH3/air co-firing flames should be operated far away from ηNH3 = 0.5 at rich conditions. NOX reaction pathway analysis shows the HNO pathway is dominant in fuel lean conditions. Thermal-NO pathway and NHi pathway are primary in stoichiometric ratio and fuel rich conditions, respectively.
Ammonia, made up of 17.8% hydrogen, has attracted a lot of attention in combustion community due to its zero carbon emission as a fuel in gas turbines. However, ammonia combustion still faces some ...challenges including the weak combustion and sharp NOx emissions which discourage its application. It was demonstrated that the combustion intensity of ammonia/air flame can be enhanced through adding active fuels like methane and hydrogen, while the NOx emission issue will emerge in the meantime. This study investigates regulation effect of methane and hydrogen on the emission characteristics of ammonia/air flame in a gas turbine combustor. The instantaneous OH profile and global emissions at the combustion chamber outlet are measured with Planar Laser Induced Fluorescence (PLIF) technique and the Fourier Transform Infrared (FTIR), respectively. The flames are also simulated by large eddy simulation to further reveal physical and chemical processes of the emissions formation. Results show that for NH3/air flames, the emissions behavior of the gas turbine combustor is similar to the calculated one-dimensional flames. Moreover, the NOx emissions and the unburned NH3 can be simultaneously controlled to a proper value at the equivalence ratio (φ) of approximate 1.1. The variation of NO and NO2 with φ for NH3/H2/air flames and NH3/CH4/air flames at blending ratio (Zf) of 0.1 are similar to the NH3/air flames, with the peak moving towards rich condition. This indicates that the NH3/air flame can be regulated through adding a small amount of active fuels without increasing the NOx emission level. However, when Zf = 0.3, we observe a clear large NOx emission and CO for NH3/CH4/air flames, indicating H2 is a better choice on the emission control. The LES results show that NO and OH radicals exhibit a general positive correlation. And the temperature plays a secondary role in promoting NOx formation comparing with CH4/air flame.
•The regulation effects of methane and hydrogen on NOx emission of ammonia/air flames in a swirl combustor are investigated.•The emission characteristics are verified similar between 1D simulation and the experimental results.•The flame structure detected by OH-PLIF is used to reveal NO emission qualitatively.•The relation of NO and OH is revealed by LES for the NH3/CH4/air flame.
Spintronic devices based on antiferromagnetic (AFM) materials hold the promise of fast switching speeds and robustness against magnetic fields
. Different device concepts have been predicted
and ...experimentally demonstrated, such as low-temperature AFM tunnel junctions that operate as spin-valves
, or room-temperature AFM memory, for which either thermal heating in combination with magnetic fields
or Néel spin-orbit torque
is used for the information writing process. On the other hand, piezoelectric materials were employed to control magnetism by electric fields in multiferroic heterostructures
, which suppresses Joule heating caused by switching currents and may enable low-energy-consuming electronic devices. Here, we combine the two material classes to explore changes in the resistance of the high-Néel-temperature antiferromagnet MnPt induced by piezoelectric strain. We find two non-volatile resistance states at room temperature and zero electric field that are stable in magnetic fields up to 60 T. Furthermore, the strain-induced resistance switching process is insensitive to magnetic fields. Integration in a tunnel junction can further amplify the electroresistance. The tunnelling anisotropic magnetoresistance reaches ~11.2% at room temperature. Overall, we demonstrate a piezoelectric, strain-controlled AFM memory that is fully operational in strong magnetic fields and has the potential for low-energy and high-density memory applications.
Exosomes are cell-derived nanovesicles with diameters from 30 to 150 nm, released upon fusion of multivesicular bodies with the cell surface. They can transport nucleic acids, proteins, and lipids ...for intercellular communication and activate signaling pathways in target cells. In cancers, exosomes may participate in growth and metastasis of tumors by regulating the immune response, blocking the epithelial–mesenchymal transition, and promoting angiogenesis. They are also involved in the development of resistance to chemotherapeutic drugs. Exosomes in liquid biopsies can be used as non-invasive biomarkers for early detection and diagnosis of cancers. Because of their amphipathic structure, exosomes are natural drug delivery vehicles for cancer therapy.
This review summarizes the biology, function, and applications of exosomes in cancers. Exosomes can be used as non-invasive biomarkers for early detection and diagnosis of cancers. Exosomes also act as natural drug delivery vehicles for cancer therapy. Display omitted
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