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[en] The structure stabilities and electronic properties of Mg-X (X = Ni, Pd, Ti, Nb) interfaces are studied by first-principles calculations, including the atomic mixture effect. In particular, the Mg-X interface structures are systemically investigated by minimizing the lattice mismatch, including the lattice constants, cell area, and included angle of the lattice (cell shape). It is found that the optimal interface matches are 4:7, 3:4, 7:8, 9:4 in surface cell atom numbers (limited up to 10 in consideration of computational cost) for Mg-Ni, Mg-Pd, Mg-Ti, Mg-Nb, and the corresponding interface energies are −0.01, −0.9, 0.4, 0.9 J m−2, respectively. We find that atomic mixing at the interface affects the strain, and even stablize the interfaces in the large-mismatch cases. Furthermore, exemplified with the Mg-Pd interface, we find the atoms at the interface can be exchanged under practical condition with assitance of vacancies at the interface. (paper)
[en] The process of reaching equilibrium concentrations in a binary liquid system with limited solubility is considered. The motion of the interface in the system in a nonequilibrium state is discussed. It is noted that mutual dissolution occurs naturally, without stirring. It is found that the time it takes to reach equilibrium concentrations under these conditions is several months. The dynamics of macroscopic processes accompanying the mutual dissolution of components is studied via dynamic light scattering. It is concluded that submicron-sized heterogeneities are observed in the lower phase within the first two hours after preparing a sample, when the lower phase is a mixture of liquids. If the lower phase is a pure liquid, such heterogeneities persist for more than two days. The lower and upper phases then remain microscopically homogeneous, though the interface continues to move for a long period of time.
[en] Four-dimensional (4D) bioprinting of cell-laden constructs with programmable shape-morphing structures has gained increasing attention in the field of biofabrication and tissue engineering. Currently, most of the widely used materials for 4D printing, including N-isopropylacrylamide-based polymers, are not commonly used in bioinks for cell-laden bioprinting. Herein, we propose a facile approach to create cell-laden constructs with near-infrared (NIR)-triggered shape morphing using bioinks based on alginate (the most widely used bioink for cell-laden bioprinting). Three-dimensional (3D) printed bilayered scaffolds with orthogonal structures using concentrated alginate/polydopamine (PDA) inks (14–18 wt%) showed a change in folded shape during NIR-induced dehydration. The deformation angle of the scaffold could be controlled by laser power, irradiation time and the designed patterns of the printed alginate/PDA struts in scaffolds. Then, 3D printed biphasic scaffolds consisting of alginate/PDA and cell-laden hydrogels exhibited programmable shape change under NIR stimulation. Scaffolds were able to maintain their deformed structures, and the printed cells in hydrogels retained high viability during culture in medium for at least 14 days. The biocompatible and commonly used hydrogel bioinks, NIR-triggered shape-morphing structures and maintenance of the deformed shape in the medium give this facile approach great potential for application in the field of 4D bioprinting and 4D biofabrication of artificial tissues and organs. (paper)
[en] The topic of this study is discussion aimed at developing a unified viewpoint on the problem of separation potential and separating power in the theory of separation of multicomponent molecular and isotopic mixtures. The object of study was the “generalized” separation potential for multicomponent mixtures. A critical assessment of its validity from thermodynamic viewpoint was given. The assumptions made during its derivation were analyzed.
[en] Targeted drug delivery is a promising application of microrobots owing to the capability of the microrobots to access nearly every region of the human body through the circulatory system. Research on microrobots over the past few decades has enabled substantial advances in the design of both the untethered microrobots swimming in a biofluid and the related mechanisms to carry and release therapeutic agents in a controlled manner. This paper presents a comprehensive review of the technological state of the art in untethered microrobots for targeted drug delivery applications. First, the in vivo microrobot locomotion techniques are discussed with respect of the different types of actuation energy sources such as magnetic fields, motile microorganisms, acoustic waves, and chemical reaction, outlining the respective advantages and major limitations. Subsequently, recent progress in various technologies of microrobot-driven targeted drug delivery is surveyed deliberating on the corresponding drug manipulation mechanisms: magnetically driven, motile microorganisms-driven, acoustic-aided, and stimuli-responsive hydrogels-aided. Although most studies on microrobot-driven targeted drug delivery were carried out in vitro, few among them successfully demonstrated in vivo operations in living animals. In the concluding section, current challenges and future perspectives of the microrobot-driven targeted drug delivery technology are discussed. (topical review)
[en] Additive alignment inside a polymer composite significantly affects the physical properties of the material. Many studies have attempted to predict, measure, and control additive alignment inside polymer composites with the aim of enhancing their properties. The objective of this study is to analyze additive alignment inside a mixture of ball-milled carbon fibers and liquid polydimethylsiloxane flowing in a channel. To this end, an image-processing method was developed to more quickly and accurately analyze the additive alignment in images obtained from flow visualization experiments. A process was developed to calculate the angle and length of an additive according to its location and the time at which the image was captured, by analyzing a sequence of images obtained from an optical microscope with a high-speed camera. The proposed process was applied to images composed of arbitrarily drawn lines and actual flow visualization images, and the results were verified by being compared with those of calculations based on the Hough transform or with directly measured values.
[en] Two high performance JET-ILW pulses, pertaining to the 2016 experimental campaign, have been numerically simulated with the self-consistent code COREDIV with the aim of predicting the ELM-averaged power load to the target when extrapolated to DT plasmas. The input power of about 33 MW as well as the total radiated power and the average density are similar in the two pulses, but for one of them the density is provided by combined low gas puff and pellet injection, characterized by low SOL density, for the other one by gas fuelling only, at higher SOL density. Considering the magnetic configuration of theses pulses and the presence of a significant amount of Ni (not included in the version of the code used for these simulations), a number of assumptions are made in order to reproduce numerically the main core and SOL experimental data. The extrapolation to DT plasmas at the original input power of 33 MW, and taking into account only the thermal component of the alpha-power, does not show any significant difference regarding the power to the target with respect to the DD case. In contrast, the simulations at auxiliary power 40 MW, both at the original I p = 3 MA and at I p = 4 MA, show that the power to the target for both pulses is possibly too high to be sustained for about 5 s by strike-point sweeping alone without any control by Ne seeding. Even though the target power load may decrease to about 13–15 MW with substantial Ne seeding for both pulses, as from numerical predictions, there are indications suggesting that the control of the power load may be more critical for the pulse with pellet injection, due to the reduced SOL radiation. (paper)
[en] A common question in the CSSI technique is ‘Where is the sediment coming from in a riverine catchment?’ The first step towards answering this question is to identify the source of the sediment by subcatchment. This can be achieved using a two end-member mixing model. It requires a ‘confluence’ sampling approach where sediment samples are collected in each of the two upstream tributaries, A and B, and the mixture collected far enough downstream from the confluence to allow complete mixing of the sediment from the two sources
[en] Ethical and societal issues concerning justice, safety, risks, and benefits are well-established topics in the discourses of nanotechnology innovation and development. That nanotechnology innovation should be socially and ethically responsible is generally accepted by scientists, policymakers, regulators, and industry, and the idea of public involvement and communication is part and parcel of the conceptualization of responsible technology development. This paper systematically reviews the social science research literature accumulated between 2002 and 2018 on the communication of nanotechnology. A critical and constructivist perspective on policy problems guides the analysis. Two questions are asked of this literature: what problems are identified regarding the communication of nanotechnology to the public? How can these problems be managed and/or resolved? Three different problem themes are identified: the public, societal institutions, and nanotechnology itself. While for some identified problems, there are corresponding solutions; in other instances, there is little alignment between problems and solutions. In conclusion, the paper recommends that in communicating nanotechnology to the public: (i) the objectives of communication should be defined; (ii) previous research should be used responsibly; (iii) communication strategies should be adapted to the context; and (iv) effort should not be spent trying to develop a generic framework for communication.