Mussel adhesive protein inspired coatings: a versatile method to fabricate silica films on various surfaces

A simple and versatile biomimetic strategy for the fabrication of silica films on a variety of substrates including gold, polystyrene and silicon wafers was developed using nanogram amounts per cm 2 of silicatein. The strategy exploits the adhesive property of 3,4-dihydroxyphenylalanine (DOPA) and a decapeptide (Ala-Lys-Pro-Ser-Tyr-DHP-Hyp-Thr-DOPA-Lys), important components of mussel adhesive proteins, to modify the surface of substrates. DOPA molecules polymerize to poly(DOPA) and the decapeptide forms thin films on gold substrates at pH 8.5, rendering the substrate compatible for silicatein immobilization. Nearly 50 ng cm 2 of silicatein is immobilized on poly(DOPA) and decapeptide coated surfaces where these polymer films act as "cushion" to protect the active structure and maintain the activity of the largely chemically adsorbed silicatein at ca. 95% of that experienced in solution. Uniform silica films of thickness 130-140 nm and roughness 12-14.5 nm were fabricated on coated gold surfaces. Evidence to show that this method is also applicable for the fabrication of uniform silica films on polystyrene and silicon substrates over multiple length scales in an economical way is also presented

Recent results and perspectives on cosmic backgrounds from radio to far-infrared

© 2019 World Scientific Publishing Company. Cosmological and astrophysical surveys from radio to far-infrared, in both temperature and polarization, offer a unique view of the universe properties and of the formation and evolution of its structures. The last release, close to be finalized, of the Planck mission results sets the scene for cosmological models and parameters, while the comparison with other types of data sets raises the issue of possible tensions about some parameters, first of all the Hubble constant. At the same time, on the extragalactic side, Planck carried out the deepest systematic all-sky survey of SZ galaxy clusters and detected thousands of dusty galaxies and many hundreds of extragalactic radio sources, also allowing us to investigate many specific topics, including molecular hydrogen clouds in galactic halos. The exploitation of future generation of CMB missions and the next radio facilities will allow us to deeply investigate several topics in cosmology and astrophysics, from the existence of primordial gravitational waves to the energy releases in the primeval plasma, from the dawn ages and the epoch of reionization to the formation and evolution of early galaxies and clusters, while a wide set of open astrophysical problems can be studied with future IR missions

Recent results and perspectives on cosmic backgrounds from radio to far-infrared

© 2019 World Scientific Publishing Company. Cosmological and astrophysical surveys from radio to far-infrared, in both temperature and polarization, offer a unique view of the universe properties and of the formation and evolution of its structures. The last release, close to be finalized, of the Planck mission results sets the scene for cosmological models and parameters, while the comparison with other types of data sets raises the issue of possible tensions about some parameters, first of all the Hubble constant. At the same time, on the extragalactic side, Planck carried out the deepest systematic all-sky survey of SZ galaxy clusters and detected thousands of dusty galaxies and many hundreds of extragalactic radio sources, also allowing us to investigate many specific topics, including molecular hydrogen clouds in galactic halos. The exploitation of future generation of CMB missions and the next radio facilities will allow us to deeply investigate several topics in cosmology and astrophysics, from the existence of primordial gravitational waves to the energy releases in the primeval plasma, from the dawn ages and the epoch of reionization to the formation and evolution of early galaxies and clusters, while a wide set of open astrophysical problems can be studied with future IR missions

On Secure Group Admission Control Using ICMetrics

The security of a system cannot be certified unless there are formal methods of admission control. Many techniques and protocol have been proposed that try to provide security yet do not focus on the most important question about who has access to the system. When considering group communications it is more important to understand this problem as the security of the system is dependent upon having authorized entities in the group communicating securely. Admission control has previously been studied in distributed systems but repeatedly overlooked in security. In this paper we provide a polling centred admission control system based on ICMetrics. We choose the polling based system as it considers the opinion of current group members when giving access to members wishing to join the group. Our proposed protocol is based on the use of the secure ring signature along with the latest ICMetrics technology

On the Incorporation of Secure Filter in ICMetrics Group Communications

Secure group communications present a unique environment where there can be multiple clients and hosts are trying to communicate securely within the group. As the number of clients and hosts increases the complexity of the communication security also increases. Group communications are based on a dynamic environment where the clients may join or leave the group at any moment. Hence it is important to ensure that only permitted entities have access to the group and those that have left the group or are not part of the group have no access to the group communications. This paper explores the delineation of a secure communication filter function that is applicable to group communications and is based on the latest Integrated Circuits Metrics (ICMetrics). The proposed scheme is based on the use of hash functions. To test the scalability of the scheme it has been implemented using SHA1 and SHA2

In-plane dipole coupling anisotropy of a square ferromagnetic Heisenberg monolayer

In this study we calculate the dipole-coupling-induced quartic in-plane anisotropy of a square ferromagnetic Heisenberg monolayer. This anisotropy increases with an increasing temperature, reaching its maximum value close to the Curie temperature of the system. At T=0 the system is isotropic, besides a small remaining anisotropy due to the zero-point motion of quantum mechanical spins. The reason for the dipole-coupling-induced anisotropy is the disturbance of the square spin lattice due to thermal fluctuations ('order-by-disorder' effect). For usual ferromagnets its strength is small as compared to other anisotropic contributions, and decreases by application of an external magnetic field. The results are obtained from a Heisenberg Hamiltonian by application of a mean field approach for a spin cluster, as well as from a many-body Green's function theory within the Tyablikov-decoupling (RPA).Comment: 6 pages, 2 figures, accepted for publication in RP

Schwinger boson theory of anisotropic ferromagnetic ultrathin films

Ferromagnetic thin films with magnetic single-ion anisotropies are studied within the framework of Schwinger bosonization of a quantum Heisenberg model. Two alternative bosonizations are discussed. We show that qualitatively correct results are obtained even at the mean-field level of the theory, similar to Schwinger boson results for other magnetic systems. In particular, the Mermin-Wagner theorem is satisfied: a spontaneous magnetization at finite temperatures is not found if the ground state of the anisotropic system exhibits a continuous degeneracy. We calculate the magnetization and effective anisotropies as functions of exchange interaction, magnetic anisotropies, external magnetic field, and temperature for arbitrary values of the spin quantum number. Magnetic reorientation transitions and effective anisotropies are discussed. The results obtained by Schwinger boson mean-field theory are compared with the many-body Green's function technique.Comment: 14 pages, including 7 EPS figures, minor changes, final version as publishe

Sacrificial-template-free synthesis of core-shell C@Bi2S3 heterostructures for efficient supercapacitor and H-2 production applications

Core-shell heterostructures have attracted considerable attention owing to their unique properties and broad range of applications in lithium ion batteries, supercapacitors, and catalysis. Conversely, the effective synthesis of Bi2S3 nanorod core@ amorphous carbon shell heterostructure remains an important challenge. In this study, C@Bi2S3 core-shell heterostructures with enhanced supercapacitor performance were synthesized via sacrificial-template-free one-pot-synthesis method. The highest specific capacities of the C@Bi2S3 core shell was 333.43 F g(-1) at a current density of 1 A g(-1). Core-shell-structured C@Bi2S3 exhibits 1.86 times higher photocatalytic H-2 production than the pristine Bi2S3 under simulated solar light irradiation. This core-shell feature of C@Bi2S3 provides efficient charge separation and transfer owing to the formed heterojunction and a short radial transfer path, thus efficiently diminishing the charge recombination; it also facilitates plenty of active sites for the hydrogen evolution reaction owing to its mesoporous nature. These outcomes will open opportunities for developing low-cost and noble-metal-free efficient electrode materials for water splitting and supercapacitor applications

High-quality genome assembly and comparative genomic profiling of yellowhorn (Xanthoceras sorbifolia) revealed environmental adaptation footprints and seed oil contents variations

Yellowhorn (Xanthoceras sorbifolia) is a species of deciduous tree that is native to Northern and Central China, including Loess Plateau. The yellowhorn tree is a hardy plant, tolerating a wide range of growing conditions, and is often grown for ornamental purposes in parks, gardens, and other landscaped areas. The seeds of yellowhorn are edible and contain rich oil and fatty acid contents, making it an ideal plant for oil production. However, the mechanism of its ability to adapt to extreme environments and the genetic basis of oil synthesis remains to be elucidated. In this study, we reported a high-quality and near gap-less yellowhorn genome assembly, containing the highest genome continuity with a contig N50 of 32.5 Mb. Comparative genomics analysis showed that 1,237 and 231 gene families under expansion and the yellowhorn-specific gene family NB-ARC were enriched in photosynthesis and root cap development, which may contribute to the environmental adaption and abiotic stress resistance of yellowhorn. A 3-ketoacyl-CoA thiolase (KAT) gene (Xso_LG02_00600) was identified under positive selection, which may be associated with variations of seed oil content among different yellowhorn cultivars. This study provided insights into environmental adaptation and seed oil content variations of yellowhorn to accelerate its genetic improvement