Upon cooling, glass-forming liquids experience a dynamic decoupling in the fast β and slow α process, which has greatly influenced glass physics. By exploring an extremely wide temporal and ...temperature range, we find a surprising gradual change of the relaxation profile from a single-step to a two-step decay upon cooling in various metallic glasses. This behavior implies a decoupling of the relaxation in two different processes in a glass state: a faster one likely related to the anomalous stress-dominated microscopic dynamics, and a slower one associated with subdiffusive motion at larger scales with a broader distribution of relaxation times.
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Balling defect of the additively manufactured titanium lattice implants easily leads to muscle tissue rejection, which might cause failure of implantation. Electropolishing is widely used in surface ...polishing of complex components and has potential to deal with the balling defect. However, a clad layer could be formed on the surface of titanium alloy after electropolishing, which may affect the biocompatibility of the metal implants. To manufacture lattice structured β-type Ti-Ni-Ta-Zr (TNTZ) for bio-medical applications, it is necessary to investigate the impact of electropolishing on material biocompatibility. In this study, animal experiments were conducted to investigate the in vivo biocompatibility of the as-printed TNTZ alloy with or without electropolishing; and proteomics technology was used to elaborate the results. The following conclusions were drawn: (a) a 30% oxalic acid electropolishing treatment was effective in solving balling defects, and ~21 nm amorphous clad layer would be formed on the surface of the material after polishing; (b) the electropolished TNTZ suggested decreased cell cytotoxicity and improved blood biocompatibility as compared to as-printed TNTZ; (c) the amorphous clad layer could make a barrier to prevent Ta and Zr ions from penetrating into the muscle tissue, and could form a good tissue regeneration at the implantation site during 4 weeks, indicating that the electropolished TNTZ has the potential as implants; and (d) the cells attached to the electropolished TNTZ showed higher antioxidant capacity but less proliferation than attached to as-printed TNTZ.
Graphical Abstract
The capillary pressure J-function is a dimensionless measure of the capillary pressure of a fluid in a porous medium. The function was derived based on a capillary bundle model. However, the ...dependence of the J-function on the saturation Sw is not well understood. A prediction model for it is presented based on capillary pressure model, and the J-function prediction model is a power function instead of an exponential or polynomial function. Relative permeability is calculated with the J-function prediction model, resulting in an easier calculation and results that are more representative.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plastic deformation of metallic glasses (MGs) has long been considered to be confined to nanoscale shear bands, but recently an affected zone around the shear band was found. Yet, due to technical ...limitations, the shear-band affected zone (SBAZ), which is critical for understanding shear banding and design of ductile MGs, has yet to be precisely identified. Here, by using magnetic domains as a probe with sufficiently high sensitivity and spatial resolution, we unveil the structure of SBAZs in detail. We demonstrate that shear banding is accompanied by a micrometer-scale SBAZ with a gradient in the strain field, and multiple shear bands interact through the superimposition of SBAZs. There also exists an ultra-long-range gradual elastic stress field extending hundreds of micrometers away from the shear band. Our findings provide a comprehensive picture on shear banding and are important for elucidating the micro-mechanisms of plastic deformation in glasses.
Fullerenes as a unique class of carbon allotropes have been studied extensively for their distinctive material properties and potential technological applications, including those in biology and ...medicine. Since a major focus in the latter has been on drug development and formulation, in this paper we highlight some representative studies related to such a focus, including the use of fullerenes for drug-like functions and for their improving the formulation of established drugs. Also discussed are some other potential medically relevant applications of fullerenes, such as their serving as potent agents in photodynamic therapy and magnetic imaging.
Vitrification from physical vapor deposition is known to be an efficient way for tuning the kinetic and thermodynamic stability of glasses and significantly improve their properties. There is a ...general consensus that preparing stable glasses requires the use of high substrate temperatures close to the glass transition one, T
. Here, we challenge this empirical rule by showing the formation of Zr-based ultrastable metallic glasses (MGs) at room temperature, i.e., with a substrate temperature of only 0.43T
. By carefully controlling the deposition rate, we can improve the stability of the obtained glasses to higher values. In contrast to conventional quenched glasses, the ultrastable MGs exhibit a large increase of T
of ∼60 K, stronger resistance against crystallization, and more homogeneous structure with less order at longer distances. Our study circumvents the limitation of substrate temperature for developing ultrastable glasses, and provides deeper insight into glasses stability and their surface dynamics.
We explore the correlation between a boson peak and structural relaxation in a typical metallic glass. Consistent with enthalpy recovery, a boson peak shows a memory effect in an aging-and-scan ...procedure. Single-step isothermal aging produces a monotonic decrease of enthalpy and boson peak intensity; for double-step isothermal aging, both enthalpy and boson peak intensity experience, coincidently, an incipient increase to a maximum and a subsequent decrease toward the equilibrium state. Our results indicate a direct link between slow structural relaxation and fast boson peak dynamics, which presents a profound understanding of the two dynamic behaviors in glass.
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The effects of spongy graphene on the latent heat and thermal conductivity of the phase change material consisting of docosane and spongy graphene were studied. The latent heat and thermal ...conductivity of docosane/graphene composites were simultaneously enhanced in contrast to that of pure docosane. The latent heat increased from 256.1J/g to 262.8J/g, and the thermal conductivity increased more than 2 times in a low graphene concentration of ~3mg/cm3. X-ray diffractometer, scanning electron microscopy, and Fourier-transform infrared spectrometer were used to characterize the microstructure of docosane and docosane/graphene composite. It is found that the crystallinity of layered docosane was enhanced in the presence of spongy graphene sheets acting as a nucleating agent, which resulted in the increase of latent heat. The enhancement of thermal conductivity for docosane/graphene composite is attributed to the high thermal conductivity of graphene.
Display omitted The simultaneous enhancement of latent heat and thermal conductivity of docosane/graphene composite is attributed to the formation of layered docosane with higher crystallinity in the presence of spongy graphene sheets acting as a nucleating agent.
•The PCM composite consisting of docosane and spongy graphene (G22) is prepared.•The latent heat and thermal conductivity of G22 are simultaneously increased.•The latent heat increase is due to formation of docosane with higher crystallinity.•Graphene sheets act as a nucleating agent to enhance the docosane crystallinity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Clostridium difficile can cause antibiotic‐associated diarrhoea or pseudo‐membranous colitis in humans and animals. Currently, the various methods such as microbiological culture, cytotoxic assay, ...ELISA and polymerase chain reaction have been used to detect Clostridium difficile infection (CDI). These conventional methods, however, require long detection time and professional staff. The paper is to describe a simple strategy which employs immunomagnetic separation and aptamer‐mediated colorimetric assay for the detection of toxin B of C. difficile (TcdB) in the stool samples. HRP‐labelled aptamer against TcdB selected by SELEX was firstly captured on the surface of magnetic beads (MB) by DNA hybridization with a complementary strand. In the presence of TcdB, aptamer specifically recognized and bound TcdB, disturbing the DNA hybridization and causing the release of HRP‐aptamer from MB. This reduced the catalytic capacity of HRP and consequently the absorption intensity. As there was a relationship between the decrease in the absorption intensity and target concentration, a quantitative analysis of TcdB can be accomplished by the measurement of the absorption intensity. Under the optimal conditions, the assay system is able to detect TcdB at a concentration down to 5 ng ml−1. Moreover the method had specificity of 97% and sensitivity of 66% and the system remained excellent stability within 4 weeks. The proposed method is a valuable screening procedure for CDI and can be extended readily to detection of other clinically important pathogens.
Significance and Impact of the Study: The paper is to describe a simple strategy for the detection of toxin B of Clostridium difficile in the stool samples. The proposed method not only showed good selectivity and sensitivity, but also did not require the special equipment and expertise. Therefore, the proposed method might become a promising candidate procedure for C. difficile infection.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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