The parallax distorsion via a weak microlensing effect

Parallax measurements allow distances to celestial objects to be determined. Coupled with measurement of their position on the celestial sphere, it gives a full three-dimensional picture of the location of the objects relative to the observer. The distortion of the parallax value of a remote source affected by a weak microlensing is considered. This means that the weak microlensing leads to distortion of the distance scale. It is shown that the distortions to appear may change strongly the parallax values in case they amount to several microseconds of arc. In particular, at this accuracy many measured values of the parallaxes must be negative.Comment: 34 LaTeX pages, 12 PostScript figure (epsfig.sty

Microarcsecond instability of the celestial reference frame

The fluctuation of the angular positions of reference extragalactic radio and optical sources under the influence of the irregular gravitational field of visible Galactic stars is considered. It is shown that these angular fluctuations range from a few up to hundreds of microarcseconds. This leads to a small rotation of the celestial reference frame. The nondiagonal coefficients of the rotation matrix are of the order of a microarcsecond. The temporal variation of these coefficients due to the proper motion of the foreground stars is of the order of one microsecond per 20 years. Therefore, the celestial reference frame can be considered inertial and homogeneous only to microarcsecond accuracy. Astrometric catalogues with microarcsecond accuracy will be unstable, and must be reestablished every 20 years.Comment: 5 pages, 2 figures, accepted to MNRA

Suppression of left-handed properties in disordered metamaterials

We study the effect of disorder on the effective magnetic response of composite left-handed metamaterials and their specific properties such as negative refraction. We show that relatively weak disorder in the split-ring resonators can reduce and even completely eliminate the frequency domain where the composite material demonstrates the left-handed properties. We introduce the concept of the order parameter to describe novel physics of this effect.Comment: 4 pages, 2 figure

Birefringent left-handed metamaterials and perfect lenses

We describe the properties of birefringent left-handed metamaterials and introduce the concept of a birefringent perfect lens. We demonstrate that, in a sharp contrast to the conventional left-handed perfect lens at $\epsilon=\mu=-1$, where $\epsilon$ is the dielectric constant and $\mu$ is the magnetic permeability, the birefringent left-handed lens can focus either TE or TM polarized waves or both of them, allowing a spatial separation of the TE and TM images. We discuss several applications of the birefringent left-handed lenses such as the beam splitting and near-field diagnostics at the sub-wavelength scale.Comment: 4 pages 6 figure

Microscopic theory of thermal phase slips in clean narrow superconducting wires

We consider structure of a thermal phase-slip center for a simple microscopic model of a clean one-dimensional superconductors in which superconductivity occurs only within one conducting channel or several identical channels. Surprisingly, the Eilenberger equations describing the saddle-point configuration allow for exact analytical solution in the whole temperature and current range. This solution allows us to derive a closed expression for the free-energy barrier, which we use to compute its temperature and current dependences

Role of cytokines in pathogenesis, diagnosis and efficiency evaluation of immunotherapy in various variants of sclerotic lichen in women

Our aim was to evaluate diagnostic and pathogenetic significance of plasma cytokines (IL-20, IL-23, IL-10, TNFα, IFNγ) in the patients with various clinical and histological variants of sclerotic lichen and to assess opportunity for their use as effectiveness criteria of immunotherapy for this disease using a drug based on eukaryotic deoxyribonucleic acid (Derinat). The prospective cohort study included assessment of the clinical manifestations (itching and dyspareunia) and measurement of blood cytokine contents (IL-20, IL-23, IL-10, TNFα, IFNγ) in women (n = 114) with various clinical variants of sclerotic lichen (atrophic, sclerotic and sclerotic-atrophic) before and after immunotherapy with a nucleic acid-based drug (Derinat). Derinat was chosen due to the fact of being an agonist of Toll-like receptors, and a number of immunoregulatory effects, including the ability to modulate cytokine production and to exert a positive influence upon regeneration processes. In addition, based on visual inspection, vulvoscopy and morphohistochemical examination results (evaluation criteria: skin thickness, number of collagen fibers, severity of fibrosis and sclerosis, etc.), the corresponding subgroups were classified within the II group, i.e., 2.1 (minimal sclerotic signs, n = 14), and 2.2 (pronounced sclerotic signs, n = 20). The control group consisted of conditionally healthy women, without history or presence of vulvar pathology (n = 30), with an age ranging from 20 to 50 years. Along with cytokine assessment by enzyme immunoassay, the study used the data of clinical examination (anamnesis collection, examination, palpation, vulvoscopy), as well as complex morphohistochemical evaluation of vulvar tissues. In atrophic variant, we have observed an increase in plasma IL-23 content, along with decreased TNFα; in lichen sclerosis, a maximal increase in IL-20, IL-23, and IFNγ was revealed; in sclerotic form of sclerotic lichen variant with severe sclerotic features, maximally enhanced IL-20, IL-23, TNFα, IFNγ, along with minimal levels of IL-10 was registered, as compared with other groups. Immunotherapy using Derinate resulted into significant reduction in the clinical manifestations in sclerotic lichen, i.e., itching of the vulva and dyspareunia, as well as normalization of cytokine indexes. Our studies have demonstrated an opportunity of using plasma concentrations of IL-20, IL-23, IL-10, TNFα, IFNγ as biomarkers of sclerotic lichen variants, and as laboratory criteria for efficiency of immunotherapy

The influence of Galactic aberration on precession parameters determined from VLBI observations

The influence of proper motions of sources due to Galactic aberration on precession models based on VLBI data is determined. Comparisons of the linear trends in the coordinates of the celestial pole obtained with and without taking into account Galactic aberration indicate that this effect can reach 20 $\mu$as per century, which is important for modern precession models. It is also shown that correcting for Galactic aberration influences the derived parameters of low-frequency nutation terms. It is therefore necessary to correct for Galactic aberration in the reduction of modern astrometric observations

Immune pathogenesis and immune therapy of a sclerosing variant of vulvar lichen sclerosus: a prospective cohort study

Background. Today, no unified clinical classification of vulvar lichen sclerosus is registered (is yet to be registered?). Isolation of pathogenetically and clinically different variants of its course enable new approaches to the treatment to be developed. Objective. To develop a pathogenetic therapy for the sclerosing variant of vulvar lichen sclerosus, taking into account its clinical and immunological characteristics. Methods. A prospective cohort study was conducted from 2018 to 2022 on the basis of Regional Clinical Hospital No. 2, Krasonodar, Russia. 292 patients aged 20 to 70 years were histologically diagnosed with vulvar lichen sclerosus. After a clinical examination using the scale for assessing subjective and objective clinical signs of vulvar lichen sclerosus, 154 patients with a sclerosing variant of the disease course were selected for the study. The control cohort consisted of 30 women of the same age category without vulvar lichen sclerosus, taking into account the exclusion criteria. The study involved a clinical assessment (in points) of objective and subjective criteria characteristic of this variant of vulvar lichen sclerosus, as well as an assessment of the level of cytokines (interleukin-20; interleukin-23; interleukin-10; tumor necrosis factor α, interferon γ) in peripheral blood of the patients from the main and control groups. One month after the immunotherapy with sodium deoxyribonucleate, the authors evaluated its clinical efficacy (using Numerical rating scale for pain (vulvodynia) and Vulvar pruritus severity scale) and immunological efficacy (repeated assessment of the level of the studied cytokines). Analysis and statistical processing of the obtained data were performed using Graph Pad Prism version 6.0 (GraphPad Software, Inc., San Diego, CA). Results. Depigmentation of the vulvar skin against the background of vulvar sclerosis and thickening features a sclerosing variant of vulvar lichen sclerosus compared to vulvar atrophy. Stenosis of the vaginal vestibule is either absent (51.3%) or predominantly corresponds to grade I, and is less specific than depigmentation and even skin atrophy. The subjective signs include a severe vulvar pruritus without or with moderately expressed (in 68.1%) vulvodynia. An immunological study showed a statistically significant increase in the level of interleukin-20 (p < 0.0001), interleukin-23 (p < 0.0001), interferon-γ (p < 0.03), tumor necrosis factor α (p < 0.009) in patients with maximal tissue sclerosis with respect to the control group, along with a statistically significant decrease in the level of anti-inflammatory interleukin-10 (p < 0.01). The immunological efficacy of sodium deoxyribonucleate was confirmed by a statistically significant (compared to baseline) decrease in interleukin-20 (p < 0.0001), interferon-γ and tumor necrosis factor α (p < 0.002), interleukin-23 (p < 0.012) without statistical differences with the control group (except for interleukin-23, the level of which decreased after therapy but remained statistically higher (p < 0.01) than in the control group). Clinical efficacy of immunotherapy was confirmed by a statistically significant (p < 0.001) reduction in vulvodynia and vulvar pruritus after the treatment. Conclusion. The obtained data demonstrate characteristic clinical features and immunological differences in relation to the norm in women with the sclerosing variant of vulvar lichen sclerosus, thereby justifying the use of sodium deoxyribonucleate in this variant with confirmed clinical and immunological efficacy