472 research outputs found
Layer-resolved magnetic exchange interactions of surfaces of late 3d elements: effects of electronic correlations
We present the results of an ab initio study of magnetic properties of Fe, Co
and Ni surfaces. In particular, we discuss their electronic structure and
magnetic exchange interactions (Jij), as obtained by means of a combination of
density functional theory and dynamical mean-field theory. All studied systems
have a pronounced tendency to ferromagnetism both for bulk and surface atoms.
The presence of narrow-band surface states is shown to enhance the magnetic
moment as well as the exchange couplings. The most interesting results were
obtained for the Fe surface where the atoms have a tendency to couple
antiferromagnetically with each other. This interaction is relatively small,
when compared to interlayer ferromagnetic interaction, and strongly depends on
the lattice parameter. Local correlation effects are shown to lead to strong
changes of the overall shape of the spectral functions. However, they seem to
not play a decisive role on the overall picture of the magnetic couplings
studied here. We have also investigated the influence of correlations on the
spin and orbital moments of the bulk-like and surface atoms. We found that
dynamical correlations in general lead to enhanced values of the orbital
moment.Comment: 13 pages, 12 figure
Magnetic properties of Ruddlesden-Popper phases SrY(FeNi)O: A combined experimental and theoretical investigation
We present a comprehensive study of the magnetic properties of
SrY(FeNi)O ().
Experimentally, the magnetic properties are investigated using superconducting
quantum interference device (SQUID) magnetometry and neutron powder diffraction
(NPD). This is complemented by the theoretical study based on density
functional theory as well as the Heisenberg exchange parameters. Experimental
results show an increase in the N\'eel temperature () with the increase of
Y concentrations and O occupancy. The NPD data reveals all samples are
antiferromagnetically ordered at low temperatures, which has been confirmed by
our theoretical simulations for the selected samples. Our first-principles
calculations suggest that the 3D magnetic order is stabilized due to finite
inter-layer exchange couplings. The latter give rise to a finite inter-layer
spin correlations which disappear above the
Developing a new model of service quality in hotels during infection disease outbreak (case study Covid-19)
3,3′,5,5′-Tetranitrobiphenyl
The title compound, C12H6N4O8, is a biphenyl system that was synthesized as a building block for a new series of antimalarial compounds. The aromatic rings are oriented at a dihedral angle of 45.5 (2)°, and intermolecular short O⋯O contacts form a chain along the b axis. The strength of the interactions involved in this chain cause one of the rings to be slightly distorted, with the torsion angle between the nitro groups being 23.4 (2)°, whereas, in the other ring, both nitro systems are parallel, forming an angle of 9.6 (2)° with the plane of the aromatic ring to which they are bound. Furthermore, the three ring C atoms around the ring–ring linkage belong to a plane inclined by 4.5 (1)° in relation to the plane containing the other three C atoms, i.e. (NO2–)C—C—C(NO2). This distortion of the ring causes uncommonly short intermolecular O⋯O [3.038 (2) Å] and O⋯C [3.000 (4) and 3.214 (1) Å] contacts
Metamaterial-Inspired Quad-Band Notch Filter for LTE Band Receivers and WPT Applications
A new compact quad-band notch filter (QBNF) based on the extended composite right and left-handed transmission line (E-CRLH TL) has been presented. As known, E-CRLH TL behaves like a quad-band structure. A microstrip TL which is loaded with an open-ended ECRLH TL is presented as a QBNF. Four unwanted frequencies were used in a dual-band LTE receiver as four notch frequencies which must be eliminated (0.9 GHz, 1.3 GHz, 2.55 GHz, and 3.35 GHz). Also, this QBNF can be applied to simultaneous wireless power and data transfer (SWPDT) system to isolate the wireless power circuit from the data communication circuit. A design technique for the proposed QBNF is presented and its performance is validated using full-wave simulation results and theoretical analysis. The main advantage of this design is an overall rejection greater than 20dB at selected unwanted frequencies. Good agreements between the fullwave simulation and equivalent circuit model results have been achieved which verified the effectiveness of the proposed circuit model. The proposed QBNF is designed on an FR-4 substrate and the dimension of the proposed QBNF is 20 * 22 mm
Entropic force approach in a noncommutative charged black hole and the equivalence principle
Recently, Verlinde has suggested a novel model of duality between
thermodynamics and gravity which leads to an emergent phenomenon for the origin
of gravity and general relativity. In this paper, we investigate some features
of this model in the presence of noncommutative charged black hole by
performing the method of coordinate coherent states representing smeared
structures. We derive several quantities, e.g. temperature, energy and entropic
force. Our approach clearly exhibits that the entropic force on a smallest
fundamental cell of holographic surface with radius is halted.
Accordingly, we can conclude that the black hole remnants are absolutely inert
without gravitational interactions. So, the equivalence principle of general
relativity is contravened due to the fact that it is now possible to find a
difference between the gravitational and inertial mass. In other words, the
gravitational mass in the remnant size does not emit any gravitational field,
therefore it is experienced to be zero, contrary to the inertial mass. This
phenomenon illustrates a good example for a feasible experimental confirmation
to the entropic picture of Newton's Second law in very short distances.Comment: 11 pages, 2 figure
Virotheranostics, a double-barreled viral gun pointed toward cancer; Ready to shoot?
Compared with conventional cancer treatments, the main advantage of oncolytic virotherapy is its tumor-selective replication followed by the destruction of malignant cells without damaging healthy cells. Accordingly, this kind of biological therapy can potentially be used as a promising approach in the field of cancer management. Given the failure of traditional monitoring strategies (such as immunohistochemical analysis (in providing sufficient safety and efficacy necessary for virotherapy and continual pharmacologic monitoring to track pharmacokinetics in real-time, the development of alternative strategies for ongoing monitoring of oncolytic treatment in a live animal model seems inevitable. Three-dimensional molecular imaging methods have recently been considered as an attractive approach to overcome the limitations of oncolytic therapy. These noninvasive visualization systems provide real-time follow-up of viral progression within the cancer tissue by the ability of engineered oncolytic viruses (OVs) to encode reporter transgenes based on recombinant technology. Human sodium/iodide symporter (hNIS) is considered as one of the most prevalent nuclear imaging reporter transgenes that provides precise information regarding the kinetics of gene expression, viral biodistribution, toxicity, and therapeutic outcomes using the accumulation of radiotracers at the site of transgene expression. Here, we provide an overview of pre-clinical and clinical applications of hNIS-based molecular imaging to evaluate virotherapy efficacy. Moreover, we describe different types of reporter genes and their potency in the clinical trials
Correction to: Virotheranostics, a double-barreled viral gun pointed toward cancer; ready to shoot? (Cancer Cell International, (2020), 20, 1, (131), 10.1186/s12935-020-01219-6)
An amendment to this paper has been published and can be accessed via the original article. © 2020, The Author(s)
Metabolic host response and therapeutic approaches to influenza infection
Based on available metabolomic studies, influenza infection affects a variety of cellular metabolic pathways to ensure an optimal environment for its replication and production of viral particles. Following infection, glucose uptake and aerobic glycolysis increase in infected cells continually, which results in higher glucose consumption. The pentose phosphate shunt, as another glucose-consuming pathway, is enhanced by influenza infection to help produce more nucleotides, especially ATP. Regarding lipid species, following infection, levels of triglycerides, phospholipids, and several lipid derivatives undergo perturbations, some of which are associated with inflammatory responses. Also, mitochondrial fatty acid β-oxidation decreases significantly simultaneously with an increase in biosynthesis of fatty acids and membrane lipids. Moreover, essential amino acids are demonstrated to decline in infected tissues due to the production of large amounts of viral and cellular proteins. Immune responses against influenza infection, on the other hand, could significantly affect metabolic pathways. Mainly, interferon (IFN) production following viral infection affects cell function via alteration in amino acid synthesis, membrane composition, and lipid metabolism. Understanding metabolic alterations required for influenza virus replication has revealed novel therapeutic methods based on targeted inhibition of these cellular metabolic pathways
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