Electronic Structure of N₂P₂ Four-Membered Rings

The biradicaloid character of the ground-state structures of N2P2 rings is studied by using the high-level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet–triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet–triplet energy gaps, the occupation numbers of antibonding-like orbitals, and the weights of the main configuration state functions (CSFs) of the ground-state wavefunctions, that is, Ψ(1A1), are used to derive the biradicaloid character that ranges from 10–15 %

Itinerant ferromagnetism and intrinsic anomalous Hall effect in amorphous iron-germanium

The amorphous iron-germanium system (a-FexGe1-x) lacks long-range structural order and hence lacks a meaningful Brillouin zone. The magnetization of a-FexGe1-x is well explained by the Stoner model for Fe concentrations x above the onset of magnetic order around x=0.4, indicating that the local order of the amorphous structure preserves the spin-split density of states of the Fe-3d states sufficiently to polarize the electronic structure despite k being a bad quantum number. Measurements reveal an enhanced anomalous Hall resistivity ρxyAH relative to crystalline FeGe; this ρxyAH is compared to density-functional theory calculations of the anomalous Hall conductivity to resolve its underlying mechanisms. The intrinsic mechanism, typically understood as the Berry curvature integrated over occupied k states but shown here to be equivalent to the density of curvature integrated over occupied energies in aperiodic materials, dominates the anomalous Hall conductivity of a-FexGe1-x (0.38≤x≤0.61). The density of curvature is the sum of spin-orbit correlations of local orbital states and can hence be calculated with no reference to k space. This result and the accompanying Stoner-like model for the intrinsic anomalous Hall conductivity establish a unified understanding of the underlying physics of the anomalous Hall effect in both crystalline and disordered systems

Out-of-surface vortices in spherical shells

The interplay of topological defects with curvature is studied for out-of-surface magnetic vortices in thin spherical nanoshells. In the case of easy-surface Heisenberg magnet it is shown that the curvature of the underlying surface leads to a coupling between the localized out-of-surface component of the vortex with its delocalized in-surface structure, i.e. polarity-chirality coupling.Comment: 6 pages, 4 figure

Oblikovanje i vrednovanje plutajućih uljnih mikrozrnaca loratadina s produljenim zadržavanjem u želucu

Gastro retentive controlled release system of loratadine was formulated to increase the residence time in stomach and to modulate the release behaviour of the drug. Oil entrapped floating microbeads prepared by emulsion gelation method were optimized by 23 factorial design and a polymer ratio of 2.5:1.5 (pectin: sodium alginate) by mass, 15% (m/v) of oil (mineral oil or castor oil) and 0.45 mol L-1 calcium chloride solution were selected as the optimized processing conditions for the desired buoyancy and physical stability. In vitro drug release in fed state conditions demonstrated sustained release of loratadine for 8 h that best fitted the Peppas model with n < 0.45. The ethylcellulose coating on microbeads optimized by 22 factorial design resulted in controlled release formulation of loratadine that provided zero-order release for 8 h.U radu je opisana priprava plutajućih mikrozrnaca za kontrolirano oslobađanje loratadina metodom želiranja emulzije. Mikrozrnca sadrže ulja, a njihovo zadržavanje u želucu je produljeno. Priprava mikrozrnaca je optimirana 23 faktorijalnim dizajnom. Pripravci optimalne sposobnosti plutanja i stabilnosti dobiveni su uz omjer masa pektina i natrijevog alginata 2,5:1,5, udio mineralnog ulja ili ulja kastora 15% (m/v) i koncentraciju kalcijevog klorida 0,45 mol L1. Iz tih se mikrozrnaca loratadin oslobađa in vitro tijekom 8 h, a oslobađanje slijedi Peppasov model ako je n < 0,45. Mikrozrnca presvučena etilcelulozom optimirana 22 faktorijalnim dizajnom slijede kinetiku nultog reda tijekom 8 h

Reconfigurable ferromagnetic liquid droplets.

Solid ferromagnetic materials are rigid in shape and cannot be reconfigured. Ferrofluids, although reconfigurable, are paramagnetic at room temperature and lose their magnetization when the applied magnetic field is removed. Here, we show a reversible paramagnetic-to-ferromagnetic transformation of ferrofluid droplets by the jamming of a monolayer of magnetic nanoparticles assembled at the water-oil interface. These ferromagnetic liquid droplets exhibit a finite coercivity and remanent magnetization. They can be easily reconfigured into different shapes while preserving the magnetic properties of solid ferromagnets with classic north-south dipole interactions. Their translational and rotational motions can be actuated remotely and precisely by an external magnetic field, inspiring studies on active matter, energy-dissipative assemblies, and programmable liquid constructs

Marginal zone lymphomas in children and the young adult population; characterization of genetic aberrations by FISH and RT-PCR

Marginal zone lymphomas present rarely in children and young adults as either primary nodal or extranodal disease and have an excellent prognosis. To date, chromosomal aberrations have not been analyzed in the pediatric and young adult population. We undertook a study to analyze genetic alterations in nodal and extranodal marginal zone lymphomas in children and young adults using fluorescence in situ hybridization (FISH) and RT-PCR. These findings were correlated with clinical features at presentation and immunophenotype. Forty-one cases were identified meeting these criteria. The age range was 1.5-29 years old with 49% of the cases <18 years of age. 73% of the marginal zone lymphoma cases showed evidence of light chain restriction by immunohistochemistry or flow cytometry. CD43 was coexpressed in 83%. 85% of the marginal zone lymphoma cases tested showed evidence of immunoglobulin heavy chain gene rearrangement. Fifty-nine percent of the cases were nodal marginal zone lymphomas with a median age at presentation of 16 years and an M/F ratio of 7:1. Twenty-one percent of the nodal marginal zone lymphoma cases contained genetic aberrations. Seventeen percent contained trisomy 18 with one case containing an additional trisomy 3. A translocation of the immunoglobulin heavy chain gene to an unknown partner gene was present in one case. Forty-one percent of the cases were extranodal marginal zone lymphomas with a median age of 24 years and a M/F ratio of 1.4:1. Eighteen percent of the extranodal marginal zone lymphoma cases contained genetic aberrations. The t(14;18) involving the IGH and MALT1 genes was present in one case, tetraploidy was present in one case, and another case contained trisomy 3. Overall the incidence of genetic aberrations in marginal zone lymphomas in the pediatric and young adult population is low, but the aberrations seen are similar to those seen in the adult population

Mechanics of extended masses in general relativity

The "external" or "bulk" motion of extended bodies is studied in general relativity. Compact material objects of essentially arbitrary shape, spin, internal composition, and velocity are allowed as long as there is no direct (non-gravitational) contact with other sources of stress-energy. Physically reasonable linear and angular momenta are proposed for such bodies and exact equations describing their evolution are derived. Changes in the momenta depend on a certain "effective metric" that is closely related to a non-perturbative generalization of the Detweiler-Whiting R-field originally introduced in the self-force literature. If the effective metric inside a self-gravitating body can be adequately approximated by an appropriate power series, the instantaneous gravitational force and torque exerted on it is shown to be identical to the force and torque exerted on an appropriate test body moving in the effective metric. This result holds to all multipole orders. The only instantaneous effect of a body's self-field is to finitely renormalize the "bare" multipole moments of its stress-energy tensor. The MiSaTaQuWa expression for the gravitational self-force is recovered as a simple application. A gravitational self-torque is obtained as well. Lastly, it is shown that the effective metric in which objects appear to move is approximately a solution to the vacuum Einstein equation if the physical metric is an approximate solution to Einstein's equation linearized about a vacuum background.Comment: 39 pages, 2 figures; fixed equation satisfied by the Green function used to construct the effective metri