Superintegrability of the Fock-Darwin system

The Fock-Darwin system is analysed from the point of view of its symmetry properties in the quantum and classical frameworks. The quantum Fock-Darwin system is known to have two sets of ladder operators, a fact which guarantees its solvability. We show that for rational values of the quotient of two relevant frequencies, this system is superintegrable, the quantum symmetries being responsible for the degeneracy of the energy levels. These symmetries are of higher order and close a polynomial algebra. In the classical case, the ladder operators are replaced by ladder functions and the symmetries by constants of motion. We also prove that the rational classical system is superintegrable and its trajectories are closed. The constants of motion are also generators of symmetry transformations in the phase space that have been integrated for some special cases. These transformations connect different trajectories with the same energy. The coherent states of the quantum superintegrable system are found and they reproduce the closed trajectories of the classical one.Comment: 21 pages,16 figure

Anatomical and histological analysis of the salpinx and ovary in Anatolian wild goat (Capra aegagrus aegagrus)

Background: This study determined the anatomical and histological structure of the salpinx and ovary of the Anatolian wild goat (C. aegagrus aegagrus). Materials and methods: The salpinges and ovaries from four wild goats of similar ages were used. These goats were brought to the Kafkas University Wildlife Rescue and Rehabilitation Centre (Kars, Turkey) for various reasons such as traffic accidents or firearm injury, but either could not be saved or were euthanased. Results: The mean length of the ovary was 13.22 ± 1.27 mm, width was 8.46 ± 0.88 mm, thickness was 5.67 ± 0.79 mm, and weight was 0.59 ± 0.17 g. The mean length of the salpinx was 58.11 ± 14.02 mm, width was 0.80 ± 0.22 mm, thickness was 0.41 ± 0.01 mm, and weight was 0.30 ± 0.08 g. The salpinx consisted of three different regions (infundibulum, ampulla, and isthmus). These regions consisted of tunica mucosa, tunica muscularis, and tunica serosa. Prismatic epithelial cells were observed in the lamina epithelialis of the tunica mucosa in every region. Conclusions: The data resulting from this study regarding anatomical and histological structures of the salpinx and ovary in the genital system organs of Anatolian wild goat will support other studies seeking to improve reproductive efficiency and eliminate the danger of extinction of this species

Fabrication and characterization of SmCo5/Nb ferromagnetic/superconducting hybrid thin films grown by RF magnetron sputtering technique

Ferromagnet/Superconductor (F/S) bilayer hybrids show exclusive states due to the mutual interaction between the superconductor and the underlying ferromagnetic substructures in micron scale. In this work, we aimed to observe the effects of the interaction between superconductivity and magnetism, especially the phenomenon involving the orientation and the size of magnetic stripes has been investigated in a coupled ferromagnetic/superconducting thin-film structure. In the proposed F/S hybrid system by this work, superconducting niobium thin-films were combined with underlying segments of ferromagnetic SmCo5 substructures. 300 nm thick magnetic films fabricated by RF magnetron sputtering techniques were topographically grown in patterns with stripes oriented either transverse to or along the direction of current flow. The elemental and microstructural analyses were conducted by EDX, SEM and GIXRD characterization tools. Low-temperature DC transport measurements were conducted by means of four point probe method in a 9T closed-cycle cryogenic refrigeration system. Transport superconducting properties, transition temperature TC(H) and second critical field HC2(T) were measured in a range of applied magnetic field between H = 0–9 kOe for the hybrid system. The results revealed that the artificial periodic modulation of applied field through preferentially-oriented magnetic stripes could introduce normal and superconducting channels or barriers for the current flow. © 2017 Elsevier Lt

SUSY approach to Pauli Hamiltonians with an axial symmetry

A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second order symmetries, is considered. After separation of variables, the one-dimensional matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and also to the Hamiltonian hierarchies generated by intertwining operators. The spectrum is studied by means of the associated matrix shape-invariance. The relation between the intertwining operators and the second order symmetries is established and the full set of ladder operators that complete the dynamical algebra is constructed.Comment: 18 pages, 3 figure

Inserting “OFF-to-ON” BODIPY Tags into Cytokines: A Fluorogenic Interleukin IL-33 for Real-Time Imaging of Immune Cells

The essential functions that cytokine/immune cell interactions play in tissue homeostasis and during disease have prompted the molecular design of targeted fluorophores to monitor their activity in real time. Whereas activatable probes for imaging immune-related enzymes are common, many immunological functions are mediated by binding events between cytokines and their cognate receptors that are hard to monitor by live-cell imaging. A prime example is interleukin-33 (IL-33), a key cytokine in innate and adaptive immunity, whose interaction with the ST2 cell-surface receptor results in downstream signaling and activation of NF-κB and AP-1 pathways. In the present work, we have designed a chemical platform to site-specifically introduce OFF-to-ON BODIPY fluorophores into full cytokine proteins and generate the first native-like fluorescent analogues of IL-33. Among different incorporation strategies, chemical aminoacylation followed by bioorthogonal derivatization led to the best labeling results.Importantly, the BODIPY-labeled IL-33 derivatives -unlike IL-33-GFP constructs- exhibited ST2-specific binding and downstream bioactivity profiles comparable to those of the wild-type interleukin. Real-time fluorescence microscopy assays under no wash conditions confirmed the internalization of IL-33 through ST2 receptors and its intracellular trafficking through the endosomal pathway. We envision that the modularity and versatility of our BODIPY labeling platform will facilitate the synthesis of minimally tagged fluorogenic cytokines as the next generation of imaging reagents for real-time visualization of signaling events in live immune cells

Fluorescent D-amino-acids reveal bi-cellular cell wall modifications important for Bdellovibrio bacteriovorous predation

Modification of essential bacterial peptidoglycan (PG) containing cell walls can lead to antibiotic resistance, for example β-lactam resistance by L,D-transpeptidase activities. Predatory Bdellovibrio bacteriovorus are naturally antibacterial and combat infections by traversing, modifying and finally destroying walls of Gram-negative prey bacteria, modifying their own PG as they grow inside prey. Historically, these multi-enzymatic processes on two similar PG walls have proved challenging to elucidate. Here, with a PG labelling approach utilizing timed pulses of multiple fluorescent D-amino acids (FDAAs), we illuminate dynamic changes that predator and prey walls go through during the different phases of bacteria:bacteria invasion. We show formation of a reinforced circular port-hole in the prey wall; L,D-transpeptidaseBd mediated D-amino acid modifications strengthening prey PG during Bdellovibrio invasion and a zonal mode of predator-elongation. This process is followed by unconventional, multi-point and synchronous septation of the intracellular Bdellovibrio, accommodating odd- and even-numbered progeny formation by non-binary division

Localization of Dirac-like excitations in graphene in the presence of smooth inhomogeneous magnetic fields

The present article discusses magnetic confinement of the Dirac excitations in graphene in presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to $1/r$ is chosen. In the next case we choose a more realistic magnetic field which does not blow up at the origin and gradually fades away from the origin. The magnetic fields chosen do not have any finite/infinite discontinuity for finite values of the radial coordinate. The novelty of the two magnetic fields is related to the equations which are used to find the excited spectra of the excitations. It turns out that the bound state solutions of the two-dimensional hydrogen atom problem are related to the spectra of graphene excitations in presence of the $1/r$ (inverse-radial) magnetic field. For the other magnetic field profile one can use the knowledge of the bound state spectrum of a two-dimensional cut-off Coulomb potential to dictate the excitation spectra of the states of graphene. The spectrum of the graphene excitations in presence of the inverse-radial magnetic field can be exactly solved while the other case cannot be. In the later case we give the localized solutions of the zero-energy states in graphene.Comment: 9 pages, 6 figures, to appear in Journal of Physics: Condensed Matte