Glued massive particles surfaces

A novel generalization of photon surfaces to the case of massive charged particles is given for spacetimes with at least one isometry, including stationary ones. A related notion of glued massive particle surfaces is also defined. These surfaces join worldlines parametrized by a family of independent conserved quantities and naturally arise in integrable spacetimes. We describe the basic geometric properties of such surfaces and their relationship to slice-reducible Killing tensors, illustrating all concepts with a number of examples. Massive particle surfaces have potential applications in the context of uniqueness theorems, Penrose inequalities, integrability, and the description of black-hole shadows in streams of massive charged particles or photons in a medium with an effective mass and charge.Comment: 39 pages, revtex

The geometry of massive particle surfaces

We propose a generalization of Claudel, Virbhadra, and Ellis photon surfaces to the case of massive charged particles, considering a timelike hypersurface such that any worldline of a particle with mass $m$, electric charge $q$ and fixed total energy $\mathcal{E}$, initially touching it, will remain in this hypersurface forever. This definition does not directly appeal to the equations of motion, but instead make use of partially umbilic nature of the surface geometry. Such an approach should be especially useful in the case of non-integrable equations of motion. It may be applied in the theory of non-thin accretion discs, and also may serve a new tool for some general problems, such as uniqueness theorems, Penrose inequalities and hidden symmetries. The condition for the stability of the worldlines is derived, which reduces to differentiation along the flow of surfaces of a certain energy. We consider a number of examples of electrovacuum and dilaton solutions, find conditions for marginally stable orbits, regions of stable or unstable spherical orbits, stable and unstable photon surfaces, and solutions satisfying the no-force condition.Comment: 30 pages, revtex4, 5 figure

Steering of Vortices by Magnetic Field Tilting in Open Superconductor Nanotubes

In planar superconductor thin films, the places of nucleation and arrangements of moving vortices are determined by structural defects. However, various applications of superconductors require reconfigurable steering of fluxons, which is hard to realize with geometrically predefined vortex pinning landscapes. Here, on the basis of the time-dependent Ginzburg–Landau equation, we present an approach for the steering of vortex chains and vortex jets in superconductor nanotubes containing a slit. The idea is based on the tilting of the magnetic field (Formula presented.) at an angle (Formula presented.) in the plane perpendicular to the axis of a nanotube carrying an azimuthal transport current. Namely, while at (Formula presented.), vortices move paraxially in opposite directions within each half-tube; an increase in (Formula presented.) displaces the areas with the close-to-maximum normal component (Formula presented.) to the close(opposite)-to-slit regions, giving rise to descending (ascending) branches in the induced-voltage frequency spectrum (Formula presented.). At lower B values, upon reaching the critical angle (Formula presented.), the close-to-slit vortex chains disappear, yielding (Formula presented.) of the (Formula presented.) type ((Formula presented.) : an integer; (Formula presented.) : the vortex nucleation frequency). At higher B values, (Formula presented.) is largely blurry because of multifurcations of vortex trajectories, leading to the coexistence of a vortex jet with two vortex chains at (Formula presented.). In addition to prospects for the tuning of GHz-frequency spectra and the steering of vortices as information bits, our findings lay the foundation for on-demand tuning of vortex arrangements in 3D superconductor membranes in tilted magnetic fields

Steering of vortices by magnetic-field tilting in superconductor nanotubes

In planar superconductor thin films, the places of nucleation and arrangements of moving vortices are determined by structural defects. However, various applications of superconductors require reconfigurable steering of fluxons, which is hard to realize with geometrically predefined vortex pinning landscapes. Here, on the basis of the time-dependent Ginzburg-Landau equation, we present an approach for steering of vortex chains and vortex jets in superconductor nanotubes containing a slit. The idea is based on tilting of the magnetic field $\mathbf{B}$ at an angle $\alpha$ in the plane perpendicular to the axis of a nanotube carrying an azimuthal transport current. Namely, while at $\alpha=0^\circ$ vortices move paraxially in opposite directions within each half-tube, an increase of $\alpha$ displaces the areas with the close-to-maximum normal component $|B_\mathrm{n}|$ to the close(opposite)-to-slit regions, giving rise to descending (ascending) branches in the induced-voltage frequency spectrum $f_\mathrm{U}(\alpha)$. At lower $B$, upon reaching the critical angle $\alpha_\mathrm{c}$, close-to-slit vortex chains disappear, yielding $f_\mathrm{U}$ of the $nf_1$-type ($n\geq1$: an integer; $f_1$: vortex nucleation frequency). At higher $B$, $f_\mathrm{U}$ is largely blurry because of multifurcations of vortex trajectories, leading to the coexistence of a vortex jet with two vortex chains at $\alpha=90^\circ$. In addition to prospects for tuning of GHz-frequency spectra and steering of vortices as information bits, our findings lay foundations for on-demand tuning of vortex arrangements in 3D superconductor membranes in tilted magnetic fields.Comment: 4 pages, 4 figure

Методичні рекомендації до виконання лабораторних робіт з навчальної дисципліни "Загальна та спортивна фізіологія". (Загальна фізіологія) І півріччя

Методичні рекомендації до виконання лабораторних робіт з навчальної дисципліни "Загальна та спортивна фізіологія". (Загальна фізіологія) І півріччя / В. Л. Богуш, І. В. Наконечний, О. В. Кувалдіна, О. С. Яцунський, В. М. Деркач, О. В. Сокол, І. Б. Марцінковський, Ю. О. Наконечна, О. О. Адаменко, О. І. Резніченко, С. В. Гетманцев. – Миколаїв : НУК, 2021. – 108 с.Вміщено лабораторні роботи, які поділені на теоретичну частину, де розглядаються теоретичні питання, та практичну частину, де студенти оволодівають практичними навичками з кожної теми. Значна увага приділена навчально-матеріальному забезпеченню занять та питанням професійної орієнтації для подальшого застосування отриманих знань у майбутній професійній діяльності

Методичні рекомендації до виконання лабораторних робіт з навчальної дисципліни "Загальна та спортивна фізіологія". (Спортивна фізіологія) ІІ півріччя

Методичні рекомендації до виконання лабораторних робіт з навчальної дисципліни "Загальна та спортивна фізіологія". (Спортивна фізіологія) ІІ півріччя / В. Л. Богуш, І. В. Наконечний, О. В. Кувалдіна, О. С. Яцунський, В. М. Деркач, О. В. Сокол, І. Б. Марцінковський, Ю. О. Наконечна, О. О. Адаменко, О. І. Резніченко, С. В. Гетманцев. – Миколаїв : НУК, 2021. – 68 с.Вміщено методичні рекомендації до виконання лабораторних робіт. За структурою вони побудовані відповідно до курсу лекцій і містять перелік питань, які будуть розглядатись у ІІ півріччі. Призначено для студентів спеціальності 017 "Фізична культура і спорт"

Novel Biodegradable Polymeric Microparticles Facilitate Scarless Wound Healing by Promoting Re-epithelialization and Inhibiting Fibrosis

Despite decades of research, the goal of achieving scarless wound healing remains elusive. One of the approaches, treatment with polymeric microcarriers, was shown to promote tissue regeneration in various in vitro models of wound healing. The in vivo effects of such an approach are attributed to transferred cells with polymeric microparticles functioning merely as inert scaffolds. We aimed to establish a bioactive biopolymer carrier that would promote would healing and inhibit scar formation in the murine model of deep skin wounds. Here we characterize two candidate types of microparticles based on fibroin/gelatin or spidroin and show that both types increase re-epithelialization rate and inhibit scar formation during skin wound healing. Interestingly, the effects of these microparticles on inflammatory gene expression and cytokine production by macrophages, fibroblasts, and keratinocytes are distinct. Both types of microparticles, as well as their soluble derivatives, fibroin and spidroin, significantly reduced the expression of profibrotic factors Fgf2 and Ctgf in mouse embryonic fibroblasts. However, only fibroin/gelatin microparticles induced transient inflammatory gene expression and cytokine production leading to an influx of inflammatory Ly6C+ myeloid cells to the injection site. The ability of microparticle carriers of equal proregenerative potential to induce inflammatory response may allow their subsequent adaptation to treatment of wounds with different bioburden and fibrotic content

Advanced computational method for studying molecular vibrations and spectra for symmetrical systems with many degrees of freedom, and its application to fullerene

A computational method for studying molecular vibrations and spectra for symmetrical systems with many degrees of freedom was developed. The algorithm allows overcoming difficulties on the automation of calculus related to the symmetry determination of such oscillations in complex systems with many degrees of freedom. One can find symmetrized displacements and, consequently, obtain and classify normal oscillations and their frequencies. The problem is therefore reduced to the determination of eigenvectors by common numerical methods, and the algorithm simplifies the procedure of symmetry determination for normal oscillations. The proposed method was applied to studying molecular vibrations and spectra of the fullerene molecule C60, and the comparison of theoretical results with experimental data is drawn. The computational method can be further extended to other problems of group theory in physics with applications in clusters and nanostructured materials

Constructing massive particles surfaces in static spacetimes

Abstract Massive particle surface is a generalization of the photon surface, both of which translate the dynamical properties of geodesics orbiting the gravitating object onto the geometric description. The procedure for constructing the massive particle surfaces in static space-times is described in detail and the equivalence of the main results with the results of the geodesic approach is demonstrated for the following examples: Schwarzschild, Reissner–Nordström, dilatonic black holes, conformal gravity, and Culetu model