Vortex beams (also known as beams with a phase singularity) consist of spiralling wavefronts that give rise to angular momentum around the propagation direction. Vortex photon beams are widely used ...in applications such as optical tweezers to manipulate micrometre-sized particles and in micro-motors to provide angular momentum, improving channel capacity in optical and radio-wave information transfer, astrophysics and so on. Very recently, an experimental realization of vortex beams formed of electrons was demonstrated. Here we describe the creation of vortex electron beams, making use of a versatile holographic reconstruction technique in a transmission electron microscope. This technique is a reproducible method of creating vortex electron beams in a conventional electron microscope. We demonstrate how they may be used in electron energy-loss spectroscopy to detect the magnetic state of materials and describe their properties. Our results show that electron vortex beams hold promise for new applications, in particular for analysing and manipulating nanomaterials, and can be easily produced.
Anthropogenic atmospheric emissions of typical toxic heavy metals have caused worldwide concern due to their adverse effects on human health and the ecosystem. By determining the best available ...representation of time-varying emission factors with S-shape curves, we establish the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn) from primary anthropogenic activities in China for the period of 1949-2012 for the first time. Further, we allocate the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5 degree 0.5 degree grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn, during the period of 1949-2012, increased by about 22-128 times at an annual average growth rate of 5.1-8.0 %, reaching about 526.9-22 319.6 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metal smelting represent the dominant sources of heavy metal emissions. In terms of spatial variation, the majority of emissions are concentrated in relatively developed regions, especially for the northern, eastern, and southern coastal regions. In addition, because of the flourishing nonferrous metal smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on account of the current and future demand of energy-saving and pollution reduction in China.
With observations of the Interface Region Imaging Spectrograph (IRIS), we study chromospheric heating and evaporation during an M1.6 flare SOL2015-03-12T11:50. At the flare ribbons, the Mg ii 2791.59 ...line shows quasi-periodic short-duration red-wing enhancement, which is likely related to repetitive chromospheric condensation as a result of episodic heating. On the contrary, the Si iv 1402.77 line reveals a persistent red-wing asymmetry in both the impulsive and decay phases, suggesting that this line responds to both cooling downflows and chromospheric condensation. The first two episodes of red-wing enhancement occurred around 11:42 UT and 11:45 UT, when two moving brightenings indicative of heating fronts crossed the IRIS slit. The greatly enhanced red wings of the Si iv and Mg ii lines at these occasions are accompanied by an obvious increase in the line intensities and the HXR flux, suggesting two episodes of energy injection into the lower atmosphere in the form of nonthermal electrons. The Mg ii k/h ratio has a small value of ∼1.2 at the ribbons and decreases to ∼1.1 at these two occasions. Correspondingly, the Fe xxi 1354 line reveals two episodes of chromospheric evaporation, which is characterized as a smooth decrease of the blueshift from ∼300 km s−1 to nearly zero within ∼3 minutes. The Fe xxi 1354 line is entirely blueshifted in the first episode, while it appears to contain a nearly stationary component and a blueshifted component in the second episode. Additional episodes of blueshifted Fe xxi emission are found around the northern ribbon in the decay phase, though no obvious response is detected in the Si iv and Mg ii emission. We have also examined the Fe xxi emission at the flare loop top and identified a secondary component with a ∼200 km s−1 redshift, which possibly results from the downward moving reconnection outflow. Our analysis also yields a rest wavelength of 1354.0878 0.0072 for this Fe xxi line.
In this study, we identified five strains isolated from soil and sediments able to degrade kraft lignin, aromatic dyes and lignin derivatives. Using 16S rRNA gene sequencing, the isolates were ...identified as Serratia sp. JHT01, Serratia liquefacien PT01, Pseudomonas chlororaphis PT02, Stenotrophomonas maltophilia PT03 and Mesorhizobium sp. PT04. All the isolates showed significant growth on lignin with no water‐extractable compounds. Synthetic aromatic dyes were used to assess the presence of oxidative enzymes. All the isolates were able to use the thiazine dye Methylene blue and the anthraquinone dye Remazol Brilliant Blue R as the sole carbon source. Guaiacol, veratryl alcohol and biphenyl were also mineralized by all the strains isolated. These results suggest they could be used for the treatment of aromatic pollutants and for the degradation of the lignocellulosic biomass.
Significance and Impact of the Study
The valorization of waste lignin and lignocellulosic biomass by biocatalysis opens up new possibilities for the production of value‐added substituted aromatics, biofuel and for the treatment of aromatic pollutants. Bacteria with ligninolytic potential could be a source of novel enzymes for controlled lignin depolymerization. In this work, five soil bacteria were isolated and studied. Every isolate showed significant growth on lignin and was able to degrade several lignin monomers and ligninolytic indicator dyes. They could thus be a source of novel ligninolytic enzymes as well as candidates for a bacterial consortium for the delignification of lignocellulosic biomass.
Significance and Impact of the Study: The valorization of waste lignin and lignocellulosic biomass by biocatalysis opens up new possibilities for the production of value‐added substituted aromatics, biofuel and for the treatment of aromatic pollutants. Bacteria with ligninolytic potential could be a source of novel enzymes for controlled lignin depolymerization. In this work, five soil bacteria were isolated and studied. Every isolate showed significant growth on lignin and was able to degrade several lignin monomers and ligninolytic indicator dyes. They could thus be a source of novel ligninolytic enzymes as well as candidates for a bacterial consortium for the delignification of lignocellulosic biomass.
A substantial body of evidence demonstrates that myocardial revascularisation using bilateral internal mammary arteries (BIMA) improves long-term survival compared with single/left internal mammary ...artery (LIMA) grafting. To date, limited analyses have been made regarding other short-term and long-term outcomes in BIMA strategy.
The primary aim of the present review is to update the difference in long-term survival between BIMA and LIMA grafting and to thoroughly investigate other secondary short-term and long-term clinical outcomes between these two grafting procedures.
Electronic searches were performed using three databases from their inception to November 2015. Relevant studies comparing long-term survival between BIMA and LIMA grafting were identified. Data were extracted by two independent reviewers and analysed according to predefined clinical outcomes.
Twenty-nine observational studies were identified, with a total of 89 399 patients. Overall, BIMA cohort had significantly improved long-term survival compared with LIMA cohort (HR 0.78; p<0.00001). BIMA cohort also had significantly reduced hospital mortality rates (1.2% vs 2.1%, p=0.04), cerebrovascular accidents (1.3% vs 2.9%, p=0.0003) and need for revascularisation (4.8% vs 10%, p=0.005), although the incidence of deep sternal wound infection (DSWI) was increased (1.8% vs 1.4%, p=0.0008) in this grafting strategy. Long-term cardiac-free, myocardial infarction-free and angina-free survivals were also superior for the BIMA cohort.
BIMA grafting is associated with enhanced overall long-term outcomes compared with LIMA grafting. While the BIMA cohort demonstrates an increased incidence of DSWI, the survival benefits and other morbidity advantages outweigh this short-term risk.
Topological structures based on controllable ferroelectric or ferromagnetic domain configurations offer the opportunity to develop microelectronic devices such as high-density memories. Despite the ...increasing experimental and theoretical insights into various domain structures (such as polar spirals, polar wave, polar vortex) over the past decade, manipulating the topological transformations of polar structures and comprehensively understanding its underlying mechanism remains lacking. By conducting an in-situ non-contact bias technique, here we systematically investigate the real-time topological transformations of polar structures in PbTiO
/SrTiO
multilayers at an atomic level. The procedure of vortex pair splitting and the transformation from polar vortex to polar wave and out-of-plane polarization are observed step by step. Furthermore, the redistribution of charge in various topological structures has been demonstrated under an external bias. This provides new insights for the symbiosis of polar and charge and offers an opportunity for a new generation of microelectronic devices.
The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer ...atmosphere, which is now considered a dynamic structured envelope. Recent observations by the Interface Region Imaging Spectrograph (IRIS) reveal that it is difficult to determine what is up and down, even in the cool 6000-kelvin photosphere just above the solar surface: This region hosts pockets of hot plasma transiently heated to almost 100,000 kelvin. The energy to heat and accelerate the plasma requires a considerable fraction of the energy from flares, the largest solar disruptions. These IRIS observations not only confirm that the photosphere is more complex than conventionally thought, but also provide insight into the energy conversion in the process of magnetic reconnection.
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