Lego DNA assembling, a simple in vitro method for constructing DNA molecule

Digestion-ligation based and recombination based methods for constructing recombinant DNA are the basic techniques in molecular biology and thus built one of the foundations for the modern life sciences. Here we describe a new strategy that can radically simplify some of the same task. The lego DNA assembling, based on strand annealing, allows in vitro assembly of multi DNA fragments in one step with precise junctions and excludes the need for any enzyme. As a proof of concept, we rapidly constructed plasmids from 4, 6 and 8 fragments with very high efficiencies (100%). And we found this method a powerful tool for synthetic biology, constructing a partial isoprene biosynthesis pathway (consisting of four genes) in 2 days. We also assembled a customized expression vector to show its modularity

A New Luminous blue variable in the outskirt of the Andromeda Galaxy

The hot massive luminous blue variables (LBVs) represent an important evolutionary phase of massive stars. Here, we report the discovery of a new LBV -- LAMOST J0037+4016 in the distant outskirt of the Andromeda galaxy. It is located in the south-western corner (a possible faint spiral arm) of M31 with an unexpectedly large projection distance of $\sim$ 22 kpc from the center. The optical light curve shows a 1.2 mag variation in $V$ band and its outburst and quiescence phases both last over several years. The observed spectra indicate an A-type supergiant at epoch close to the outburst phase and a hot B-type supergiant with weak [Fe II] emission lines at epoch of much dimmer brightness. The near-infrared color-color diagram further shows it follows the distribution of Galactic and M31 LBVs rather than B[e] supergiants. All the existing data strongly show that LAMOST J0037+4016 is an LBV. By spectral energy distribution fitting, we find it has a luminosity ($4.42 \pm 1.64$)$\times 10^5$ $L_{\odot}$ and an initial mass $\sim 30$ $M_{\odot}$, indicating its nature of less luminosity class of LBV.Comment: 7 pages, 4 figures, 3 tables, accepted by ApJ

System engineering and key technologies research and practice of smart mine

In order to overcome the problems existed in the construction process of complex giant system of smart mine, the overall technical framework of smart mine construction was proposed, and a detailed description was made from the aspects of smart mine system model construction, underground space reconstruction and model dynamic update, machine vision measurement technology, radio frequency explosion-proof test method of gas environment, mine safety closed-loop control system, smart mine standard system, etc. The smart mine was divided into information sensing support layer, edge computing layer, cloud data center, multi-type network, intelligent mine production management and control platform, intelligent mine production system and intelligent mine operation and maintenance management system. The smart mine technology architecture based on the deep integration of multiple systems was built. Based on the knowledge map and information extraction of smart mine, a smart mine system model driven by data innovation, based on communication network and centered on data computing power was constructed. A 3D visual space model based on machine vision perception information and supplemented by other perception information was constructed, and a 3D vision and spatial reconstruction framework of mine underground scene was proposed to realize the reconstruction and dynamic update of the 3D space of underground mine. Based on machine vision technology, the identification algorithm of downhole equipment position and coal-rock interface was developed to realize the simultaneous aerial measurement of fully mechanized mining equipment group and coal-rock interface. The limitations and shortcomings of the current explosion-proof standards on the power of 5G base stations in the underground gas environment were discussed, and a special test device for radio-frequency electromagnetic energy explosion-proof was designed and developed, which provides a method for reference to improve the power threshold of underground 5G base stations. The technical framework of mine disaster closed-loop management and control system, which integrates comprehensive perception of disaster information, independent decision-making of prevention and control plan, and coordinated control of prevention and control equipment, was proposed to realize advanced prediction and early warning and coordinated prevention and control of underground disasters. The framework of intelligent coal mine standard system was constructed, the typical cases of intelligent construction of coal mine and metal mine in China were analyzed, and the development trend and suggestions of intelligent mine construction were put forward

A solar wind-derived water reservoir on the Moon hosted by impact glass beads

The past two decades of lunar exploration have seen the detection of substantial quantities of water on the Moon’s surface. It has been proposed that a hydrated layer exists at depth in lunar soils, buffering a water cycle on the Moon globally. However, a reservoir has yet to be identified for this hydrated layer. Here we report the abundance, hydrogen isotope composition and core-to-rim variations of water measured in impact glass beads extracted from lunar soils returned by the Chang’e-5 mission. The impact glass beads preserve hydration signatures and display water abundance profiles consistent with the inward diffusion of solar wind-derived water. Diffusion modelling estimates diffusion timescales of less than 15 years at a temperature of 360 K. Such short diffusion timescales suggest an efficient water recharge mechanism that could sustain the lunar surface water cycle. We estimate that the amount of water hosted by impact glass beads in lunar soils may reach up to 2.7 × 1014 kg. Our direct measurements of this surface reservoir of lunar water show that impact glass beads can store substantial quantities of solar wind-derived water on the Moon and suggest that impact glass may be water reservoirs on other airless bodies

Continuous cleaning process of molten copper slags in a channel reactor under the external electric field

Continuous cleaning process of the molten copper slags in a channel reactor under a vertical electric field is proposed. The copper-matte settling velocity under the vertical electric field is much faster than that only under the gravity in the molten slags, and the electric field can also accelerate the magnetite reduction. Cu content in the slag can fall below 0.35 wt. % during the continuous cleaning process, which exceeds much more existing slag treatment process. In addition, the behaviours of some other heavy metal elements in the molten slags during the continuous process are also discussed

Continuous cleaning process of molten copper slags in a channel reactor under the external electric field

Continuous cleaning process of the molten copper slags in a channel reactor under a vertical electric field is proposed. The copper-matte settling velocity under the vertical electric field is much faster than that only under the gravity in the molten slags, and the electric field can also accelerate the magnetite reduction. Cu content in the slag can fall below 0.35 wt. % during the continuous cleaning process, which exceeds much more existing slag treatment process. In addition, the behaviours of some other heavy metal elements in the molten slags during the continuous process are also discussed

Diffusion Data in Silicate Melts

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