Outbreak of African swine fever in South Korea, 2019 Kim, Hyun‐Joo; Cho, Ki‐Hyun; Lee, Soo‐Kyoung ...
Transboundary and emerging diseases,
March 2020, 2020-Mar, 2020-03-00, 20200301, Letnik:
67, Številka:
2
Journal Article
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African swine fever, a fatal haemorrhagic disease of swine, was confirmed in domestic pigs for the first time in South Korea in September 2019. The causative virus belonged to the p72 genotype II and ...had an additional tandem repeat sequence in the intergenic region (IGR) between the I73R and I329L.
Apoptosis is a highly-regulated, active process of cell death involved in development, homeostasis and aging. Dysregulation of apoptosis leads to pathological states, such as cancer, developmental ...anomalies and degenerative diseases. Osteoarthritis (OA), the most common chronic joint disease in the elderly population, is characterized by progressive destruction of articular cartilage, resulting in significant disability. Because articular cartilage depends solely on its resident cells, the chondrocytes, for the maintenance of extracellular matrix, the compromising of chondrocyte function and survival would lead to the failure of the articular cartilage. The role of subchondral bone in the maintenance of proper cartilage matrix has been suggested as well, and it has been proposed that both articular cartilage and subchondral bone interact with each other in the maintenance of articular integrity and physiology. Some investigators include both articular cartilage and subchondral bone as targets for repairing joint degeneration. In late-stage OA, the cartilage becomes hypocellular, often accompanied by lacunar emptying, which has been considered as evidence that chondrocyte death is a central feature in OA progression. Apoptosis clearly occurs in osteoarthritic cartilage; however, the relative contribution of chondrocyte apoptosis in the pathogenesis of OA is difficult to evaluate, and contradictory reports exist on the rate of apoptotic chondrocytes in osteoarthritic cartilage. It is not clear whether chondrocyte apoptosis is the inducer of cartilage degeneration or a byproduct of cartilage destruction. Chondrocyte death and matrix loss may form a vicious cycle, with the progression of one aggravating the other, and the literature reveals that there is a definite correlation between the degree of cartilage damage and chondrocyte apoptosis. Because current treatments for OA act only on symptoms and do not prevent or cure OA, chondrocyte apoptosis would be a valid target to modulate cartilage degeneration.
Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were ...extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone-bioactive, mechanical, cellular and tissue attributes of MNP-incorporated PCL nanofibers make them promising candidate scaffolds for bone regeneration.
A 64-word-line-stacked 512-Gb 3-b/cell 3-D NAND flash memory is presented. After briefly examining the challenges that occur to a stack, several technologies are suggested to resolve the issues. For ...performance enhancement, a novel program method hiding two-page data loading time is presented. This paper also discusses an electrical annealing improving reliability characteristic by removing holes in shallow traps. In addition, a valley tracking read for reducing timing overhead at a read retry is introduced by fast finding optimal read levels. Finally, a high-speed self-test mode for IO operation is presented. The chip, designed with the fourth generation of V-NAND technology, achieved an areal density of 3.98 Gb/mm 2 and operated up to 1 Gb/s at 1.2 V.
Lattice defects typically reduce lattice thermal conductivity, which has been widely exploited in applications such as thermoelectric energy conversion. Here, an anomalous dependence of the lattice ...thermal conductivity on point defects is demonstrated in epitaxial WO3 thin films. Depending on the substrate, the lattice of epitaxial WO3 expands or contracts as protons are intercalated by electrolyte gating or oxygen vacancies are introduced by adjusting growth conditions. Surprisingly, the observed lattice volume, instead of the defect concentration, plays the dominant role in determining the thermal conductivity. In particular, the thermal conductivity increases significantly with proton intercalation, which is contrary to the expectation that point defects typically lower the lattice thermal conductivity. The thermal conductivity can be dynamically varied by a factor of ≈1.7 via electrolyte gating, and tuned over a larger range, from 7.8 to 1.1 W m−1 K−1, by adjusting the oxygen pressure during film growth. The electrolyte‐gating‐induced changes in thermal conductivity and lattice dimensions are reversible through multiple cycles. These findings not only expand the basic understanding of thermal transport in complex oxides, but also provide a path to dynamically control the thermal conductivity.
An anomalous dependence of thermal conductivity on point defects is observed in epitaxial WO3 thin films. In particular, an increase of the lattice thermal conductivity found in WO3/YAO is accompanied by a lattice contraction upon the introduction of point defects, suggesting that the lattice volume rather than defect concentration plays the dominant role in determining the thermal conductivity.
Structural and electrical properties of Al‐doped ZnO (AZO) films deposited by atomic layer deposition (ALD) are investigated to study the extrinsic doping mechanism of a transparent conducting oxide. ...ALD‐AZO films exhibit a unique layer‐by‐layer structure consisting of a ZnO matrix and Al2O3 dopant layers, as determined by transmission electron microscopy analysis. In these layered AZO films, a single Al2O3 dopant layer deposited during one ALD cycle could provide ≈4.5 × 1013 cm−2 free electrons to the ZnO. The effective field model for doping is suggested to explain the decrease in the carrier concentration of ALD‐AZO films when the interval between the Al2O3 layers is reduced to less than ≈2.6 nm (>3.4 at% Al). By correlating the electrical and structural properties, an extrinsic doping mechanism of ALD‐AZO films is proposed in which the incorporated Al atoms take oxygen from the ZnO matrix and form doubly charged donors, such as oxygen vacancies or zinc interstitials.
Layer‐by‐layer Al‐doped ZnO films are deposited by atomic layer deposition to study the extrinsic doping mechanism of a transparent conducting oxide. A combined understanding of structural and electrical properties of these films based on an effective field model suggests that doubly charged donors, such as oxygen vacancies and zinc interstitials, would be formed by extrinsic doping of Al atoms.
This article reviews recent fabrication methods for surface‐enhanced Raman spectroscopy (SERS) substrates with a focus on advanced nanoarchitecture based on noble metals with special nanospaces ...(round tips, gaps, and porous spaces), nanolayered 2D materials, including hybridization with metallic nanostructures (NSs), and the contemporary repertoire of nanoarchitecturing with organic molecules. The use of SERS for multidisciplinary applications has been extensively investigated because the considerably enhanced signal intensity enables the detection of a very small number of molecules with molecular fingerprints. Nanoarchitecture strategies for the design of new NSs play a vital role in developing SERS substrates. In this review, recent achievements with respect to the special morphology of metallic NSs are discussed, and future directions are outlined for the development of available NSs with reproducible preparation and well‐controlled nanoarchitecture. Nanolayered 2D materials are proposed for SERS applications as an alternative to the noble metals. The modern solutions to existing limitations for their applications are described together with the state‐of‐the‐art in bio/environmental SERS sensing using 2D materials‐based composites. To complement the existing toolbox of plasmonic inorganic NSs, hybridization with organic molecules is proposed to improve the stability of NSs and selectivity of SERS sensing by hybridizing with small or large organic molecules.
A summary of advances in developing surface‐enhanced Raman spectroscopy (SERS)‐active substrates via fabrication methods of nanostructured metals and 2D materials is provided. Approaches for controlling metal tips/gaps/pores including advantages and disadvantages are discussed. Moreover, recent advances and challenges of novel 2D‐layered SERS‐active substrates are presented. Functionalization strategies for SERS surfaces include use of small or large molecules to complement the preparation procedures.
A 3D laser coating technology using Cr powder was developed for Zr-based alloys considering parameters such as: the laser beam power, inert gas flow, cooling of Zr-based alloys, and Cr powder ...control. This technology was then applied to Zr cladding tube samples to study the effect of Cr coating on the high-temperature oxidation of Zr-based alloys in a steam environment of 1200 °C for 2000s. It was revealed that the oxide layer thickness formed on the Cr-coated tube surface was about 25-times lower than that formed on a Zircaloy-4 tube surface. In addition, both the ring compression and the tensile tests were performed to evaluate the adhesion properties of the Cr-coated sample. Although some cracks were formed on the Cr-coated layer, the Cr-coated layer had not peeled off after the two tests.
Current cell‐based therapies administered after myocardial infarction (MI) show limited efficacy due to subpar cell retention in a dynamically beating heart. In particular, cardiac patches generally ...provide a cursory level of cell attachment due to the lack of an adequate microenvironment. From this perspective, decellularized cell‐derived ECM (CDM) is attractive in its recapitulation of a natural biophysical environment for cells. Unfortunately, its weak physical property renders it difficult to retain in its original form, limiting its full potential. Here, a novel strategy to peel CDM off from its underlying substrate is proposed. By physically stamping it onto a polyvinyl alcohol hydrogel, the resulting stretchable extracellular matrix (ECM) membrane preserves the natural microenvironment of CDM, thereby conferring a biological interface to a viscoelastic membrane. Its various mechanical and biological properties are characterized and its capacity to improve cardiomyocyte functionality is demonstrated. Finally, evidence of enhanced stem cell delivery using the stretchable ECM membrane is presented, which leads to improved cardiac remodeling in a rat MI model. A new class of material based on natural CDM is envisioned for the enhanced delivery of cells and growth factors that have a known affinity with ECM.
Here, an intriguing strategy is proposed to detach cell‐derived extracellular matrix (CDM) from its underlying substrate by physically stamping it onto a polyvinyl alcohol hydrogel which suggests potential as a cardiac patch. It also provides a dynamic environment in which cells directly interact with CDM under the cyclic tensional forces.
Black melanin inks are prepared to selectively exhibit colors under strong light, inspired by human hair. High absorbance of melanin suppresses multiple scattering, causing resonant Mie scattering ...predominant. Various colors can be developed as the resonant wavelength dictated by nanosphere diameter. Therefore, the melanin inks can be used to encrypt and selectively disclose multicolor patterns for anticounterfeiting applications.
Black melanin inks are prepared to selectively exhibit colors under strong light, inspired by human hair. The high absorbance of melanin suppresses multiple scattering, causing resonant Mie scattering to be predominant. Various colors can be developed as the resonant wavelength dictated by nanosphere diameter. Therefore, the melanin inks can be used to encrypt and selectively disclose multicolor patterns for anticounterfeiting applications.
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