141 research outputs found

    Pulsations and Long-Term Light Variability of Three Candidates to Protoplanetary Nebulae

    Full text link
    We present new photometric data and analysis of the long-duration UBV photoelectric observations for three candidates to protoplanetary objects - F-supergiants with IR-excesses located at large galactic latitudes, IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All three stars have revealed quasiperiodic low-amplitude variabilities caused by pulsations observed against the long-term trends of brightnesses. For IRAS 18095+2704=V887 Her we have found a pulsation period of 109 days and a linear trend of brightness under the constant colours if being averaged over the year timescale. The light curve of IRAS 19386+0155=V1648 Aql over 2000-2008 can be approximated by a wave with a main period of 102 days which is modulated by close frequency, with a period of 98 days, that results in brightness oscillations with a variable amplitude. V1648 Aql has also shown synchronous reddening together with a persistent rise of brightness in the V-band. IRAS 19500-1709=V5112 Sgr experiences irregular pulsations with the periods of 39 and 47 days. The long-term component of the variability of V5112 Sgr may be related to the binary character of this star.Comment: 11 pages, 6 figures, accepted for publication in Pis'ma Astron. Z

    Immunoglobulins and predicted mortality in clinical course of concomitant HIV and TB infection

    Get PDF
    A search for prognostic markers of HIV and tuberculosis coinfection (HIV/TB), especially in case of Mycobacterium tuberculosis multidrug resistance (MDR MBT) associated with low rates of TB eradication, is of relevance in connection with the problem of choosing adequate anti-TB therapy which is able to decrease mortality. 113 HIV/TB patients aged 24 to 58 years were examined: 70 males and 43 females hospitalized at the Novokuznetsk TB Clinic during the 2017—2019 period. MDR MBT (concomitant resistance to Isoniazid and Rifampicin) was found in 50 patients (12 patients with MDR MBT had additional resistance to Fluoroquinolones) aged 24 to 54 years — 31 males and 19 females. The control group consisted of 49 healthy individuals aged 27 to 72 years (26 females and 23 males) lacking focal and systemic infections with moderately pronounced age-related changes. In plasma samples, concentration of total (non-specific) immunoglobulins of classes E, M, G, A (including secretory immunoglobulin A, sIgA) were measured by using enzyme-linked immunosorbent assay. Data statistical processing was performed by using licensed software packages InStatII, Microsoft Excel, IBM SPSS Statistics 22. An extended range of individual variability in count of peripheral blood CD4 lymphocytes was revealed both among non-survivor and survivor patients with HIV/TB examined, being a drawback of using such parameter as lethality predictor. It was found that the serum level of total IgE, IgM, IgG, IgA and sIgA in patients with HIV/ TB was higher than that one in control group, whereas in non-survivor vs. survivor patients the concentration of IgE and sIgA was elevated. The coefficient of disease outcome prediction (CP) for patients with HIV/TB and MDR MBT was calculated being equal to the ratio of the multiplication of serum concentration of IgE, IgM, IgA and secretory IgA to CD4 lymphocyte count (CP = IgE x IgM x IgA x sIgA/CD4). CP higher than 200 was detected in 77% non-survivor and 6% of survivor patients. The relative risk of death with CP > 200 was very high (OR = 56.7, p < 0.0001) being 8.5 times higher than that one upon CD4 < 200 (OR = 6.7, p = 0.0237). A positive correlation between CP and lethal outcome was more valuable than that of CD4. The data presented allow us to propose CP for clinical use as an effective prognostic criterion for HIV/TB with MDR MBT

    Association of leptin receptor Gln223Arg genetic polymorphism with obesity and non-alcoholic fatty liver disease

    Get PDF
    Aim of investigation. Investigation of association of leptin receptor (LEPR) gene Gln223Arg polymorphism with obesity and non-alcoholic fatty liver disease (NAFLD).Material and methods. Overall 107 patients with NAFLD, 81 patient with alcoholic liver disease (ALD) and 117 patients without liver diseases (control group) were investigated. Obesity criterion was body the body mass index (BMI) ≥30,0. Cholesterol and triglycerides serum levels were estimated by enzyme colorimetric method, leptin concentration — by immunoenzyme method. Genotyping for LEPR Gln223Arg gene polymorphism was carried out by allele — specific polymerase chain reaction.Results. In control group and ALD patients no correlation of obesity with LEPR Gln223Arg gene polymorphism was revealed. In NAFLD patients without obesity Arg223Arg genotype, as well as 223Arg allele, was less frequent, than in control group — 3 times (P<0,05) and 1,5 times (P<0,05) respectively. Frequency of this genotype / allele was also significantly less in NAFLD group without obesity, than in those with obesity. Mean serum cholesterol level at NAFLD was higher, than at ALD (Р <0,05), and in Gln223Gln genotype carriers this parameter was highest in comparison to that parameter in other groups. At NAFLD patients 223Arg variant was less frequent (49,5%), than 223Gln variant, in contrast to other groups. Allelic frequency of 223Gln in women with NAFLD was 1,5 times higher (P<0,05) , than in women with ALD, and 1,3 times higher (P<0,05), than in women of control group. Frequency of Gln223Gln genotype in women with NAFLD was higher than that in women with ALD 1,5 times (Р<0,01), in women of control group — 1,3 times (Р<0,05) and in men with NAFLD — 3 times (Р=0,05) respectively.Conclusions. Carriage of 223Gln variant of LEPR Gln223Arg gene polymorphism can promote increase of cholesterol level and development of non-alcoholic fatty liver disease in absence of obesity as well, is especial in women

    Observation of nonlinearity-controlled switching of topological edge states

    Full text link
    We report the experimental observation of the periodic switching of topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to the overlap of the modal fields of the edge states from topological forbidden gap, when they are simultaneously present in two arrays brought into close proximity. We found that the phenomenon occurs for both strongly and weakly localized edge states and that switching rate increases with decreasing spacing between the topological arrays. When topological arrays are brought in contact with nontopological ones, switching in topological gap does not occur, while one observes either the formation of nearly stationary topological interface mode or strongly asymmetric diffraction into the nontopological array depending on the position of the initial excitation. Switching between topological arrays can be controlled and even completely arrested by increasing the peak power of the input signal, as we observed with different array spacings.Comment: 8 pages, 6 figure

    Observation of π\pi solitons in oscillating waveguide arrays

    Full text link
    Floquet systems with periodically varying in time parameters enable realization of unconventional topological phases that do not exist in static systems with constant parameters and that are frequently accompanied by appearance of novel types of the topological states. Among such Floquet systems are the Su-Schrieffer-Heeger lattices with periodically-modulated couplings that can support at their edges anomalous π\pi modes of topological origin despite the fact that the lattice spends only half of the evolution period in topologically nontrivial phase, while during other half-period it is topologically trivial. Here, using Su-Schrieffer-Heeger arrays composed from periodically oscillating waveguides inscribed in transparent nonlinear optical medium, we report experimental observation of photonic anomalous π\pi modes residing at the edge or in the corner of the one- or two-dimensional arrays, respectively, and demonstrate a new class of topological π\pi solitons bifurcating from such modes in the topological gap of the Floquet spectrum at high powers. π\pi solitons reported here are strongly oscillating nonlinear Floquet states exactly reproducing their profiles after each longitudinal period of the structure. They can be dynamically stable in both one- and two-dimensional oscillating waveguide arrays, the latter ones representing the first realization of the Floquet photonic higher-order topological insulator, while localization properties of such π\pi solitons are determined by their power.Comment: 10 pages, 6 figures, to appear in Science Bulleti

    Observation of nonlinear disclination states

    Full text link
    Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at disclinations. Appearance of these topological states is consistent with the bulk-disclination correspondence principle, and is due to the filling anomaly that results in fractional charges to the boundary unit cells. So far, topological disclination states were observed only in the linear regime, while the interplay between nonlinearity and topology in the systems with disclinations has been never studied experimentally. We report here bon the experimental observation of the nonlinear photonic disclination states in waveguide arrays with pentagonal or heptagonal disclination cores inscribed in transparent optical medium using the fs-laser writing technique. The transition between nontopological and topological phases in such structures is controlled by the Kekul\'e distortion coefficient rr with topological phase hosting simultaneously disclination states at the inner disclination core and spatially separated from them corner, zero-energy, and extended edge states at the outer edge of the structure. We show that the robust nonlinear disclination states bifurcate from their linear counterparts and that location of their propagation constants in the gap and, hence, their spatial localization can be controlled by their power. Nonlinear disclination states can be efficiently excited by Gaussian input beams, but only if they are focused into the waveguides belonging to the disclination core, where such topological states reside.Comment: 11 pages, 6 figure

    Ictal and interictal MEG in pediatric patients with tuberous sclerosis and drug resistant epilepsy

    Get PDF
    Purpose: Drug resistant epilepsy (DRE) is common in patients with tuberous sclerosis (TS). Interictal MEG has been shown as a valuable instrument in the presurgical workup. The goal of our study was to evaluate the role of ictal MEG in epileptogenic tuber selection, especially in patients with multiple irritative zones. Methods: The clinical and MEG data of 23 patients with TS and DRE from two medical/research centers were reviewed. Seven pediatric patients, who had seizures during MEG recording and underwent resection or disconnection surgery, were included into the study. Cortical sources of ictal and interictal epileptiform MEG discharges were compared with epileptogenic zone location in six patients with favorable surgery outcome. Results: In patients who improved substantially after surgery all resected and several other tubers demonstrated epileptiform activity on interictal MEG. Ictal MEG provided crucial information about lobar location of the seizure onset zone (SOZ) in two cases, and in the other four it confirmed the SOZ location derived from the interictal data. In one case, ictal MEG findings were unreliable. In one patient, who did not benefit from surgical treatment, the resected tubers did not overlap with interictal and ictal MEG sources. Conclusion: The combination of interictal and ictal MEG is a valuable tool for identification of the epileptogenic tuber/tubers in presurgical work-up in patients with TS.Peer reviewe

    Observation of edge solitons in topological trimer arrays

    Get PDF
    We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from nontopological to topological phases is controlled by the spacing between neighboring trimers. We found that, in the former regime, edge solitons occur only above a considerable power threshold, whereas in the latter one they bifurcate from linear states. Edge solitons are observed in a broad power range where their propagation constant falls into one of the topological gaps of the system, while partial delocalization is observed when considerable nonlinearity drives the propagation constant into an allowed band, causing coupling with bulk modes. Our results provide direct experimental evidence of the coexistence and selective excitation in the same or in different topological gaps of two types of topological edge solitons with different internal structures, which can rarely be observed even in nontopological systems. This also constitutes the first experimental evidence of formation of topological solitons in a nonlinear system with more than one topological gap.The authors acknowledge funding of this study by RSF (grant 21‐12‐00096). Also, support by CEX2019‐000910‐S [funded by MCIN/AEI/10.13039/501100011033], Fundació Cellex, Fundació Mir‐Puig, and Generalitat de Catalunya (CERCA) is acknowledged.Peer ReviewedPostprint (author's final draft
    corecore