Inverse problem in transformation optics

The straightforward method of transformation optics implies that one starts from the coordinate transformation, determines the Jacobian matrix, the fields and material parameters of the cloak. However, the coordinate transformation appears as an optional function: it is not necessary to know it. We offer the solution of some sort of the inverse problem: starting from the fields in the invisibility cloak we directly derive the permittivity and permeability tensors of the cloaking shell. The approach can be useful for finding material parameters for the specified electromagnetic fields in the cloaking shell without knowing coordinate transformation.Comment: 7 pages, 4 figures, J. Opt, vol. 13, 201

Spin and Orbital angular momentum propagation in anisotropic media: theory

This paper is devoted to study the propagation of light beams carrying orbital angular momentum in optically anisotropic media. We first review some properties of homogeneous anisotropic media, and describe how the paraxial formalism is modified in order to proceed with a new approach dealing with a general setting of paraxial propagation along uniaxial inhomogeneous media. This approach is suitable for describing the space-variant-optical-axis phase plates

Іхтіопатологічні наслідки ураження прісноводних риб електрострумом

Наводяться дані про іхтіопатологічне обстеження двох видів статевозрілих риб із двох родин (щука, лящ) Дніпровського водосховища, вилучених під час природоохоронного рейду у громадянина, який застосовував саморобний електричний пристрій («електровудку») для ураження риб. Усі досліджені особини ляща звичайного мали ураження рогівки очей і внутрішніх органів різного ступеня. Із внутрішніх органів найбільші ураження відмічені для тканин нирок, знайдені крововиливи у черевну порожнину, нирки та головний мозок. У щуки звичайної відмічені ураження геніпор (отворів гіомандибулярного каналу) у вигляді крововиливів. Описані іхтіопатологічні наслідки ураження риб можуть використовуватися природоохоронними органами для чіткої діагностики леталь­ного впливу електроструму на гідробіонтів

Non-resonant terahertz field enhancement in periodically arranged nanoslits

We analyze ultra strong non-resonant field enhancement of THz field in periodic arrays of nanoslits cut in ultrathin metal films. The main feature of our approach is that the slit size and metal film thickness are several orders of magnitude smaller than the wavelength k of the impinging radiation. Two regimes of operation are found. First, when the grating period, frequency-independent enhancement is observed, accompanied by a very high transmission approaching unity. With high accuracy, this enhancement equals the ratio of P to the slit width w. Second, when the grating period approaches the THz wavelength but before entering the Raleigh-Wood anomaly, the field enhancement in nanoslit stays close to that in a single isolated slit, i.e., the well-known inversefrequency dependence. Both regimes are non-resonant and thus extremely broadband. The results are obtained by the microscopic Drude-Lorentz model taking into account retardation processes in the metal film and validated by the finite difference frequency domain method. We expect sensor and modulation applications of the predicted giant broadband field enhancement

Risk of sudden cardiac death in strength training

Physical activity is a generally accepted means of primary and secondary prevention of cardiovascular diseases, but in some cases, it can be a risk factor for cardiovascular events, including sudden cardiac death (SCD). Most studies analyze the relationship of cardiovascular events with the volume and general directions of exercise. Besides, a significant part of the guidelines and studies are devoted to the effects of aerobic exercise, while the importance of anaerobic exercise remains controversial. The review analyzes works devoted to the influence of strength training, such as weightlifting, bodybuilding, powerlifting, etc., on the cardiovascular system, as well as their relationship with SCD and other cardiovascular events. The design and contingent of the analyzed papers did not allow them to be systematized correctly. Therefore, the review is largely analytical in nature

Improvement of cardiovascular risk assessment using machine learning methods

The increase in the prevalence of cardiovascular diseases (CVDs) specifies the importance of their prediction, the need for accurate risk stratification, preventive and treatment interventions. Large medical databases and technologies for their processing in the form of machine learning algorithms that have appeared in recent years have the potential to improve predictive accuracy and personalize treatment approaches to CVDs. The review examines the application of machine learning in predicting and identifying cardiovascular events. The role of this technology both in the calculation of total cardiovascular risk and in the prediction of individual diseases and events is discussed. We compared the predictive accuracy of current risk scores and various machine learning algorithms. The conditions for using machine learning and developing personalized tactics for managing patients with CVDs are analyzed

FUNCTIONAL POLYMORPHISM OF THE PRO-INFLAMMATORY CYTOKINE GENES IN PULMONARY TUBERCULOSIS

In the present time, incidence of pulmonary tuberculosis (TB) becomes broader, due to spreading resistance of Mycobacterium tuberculosis (MBT) to anti-tuberculosis drugs and infection with highly virulent strains of M. tuberculosis. The MBT antigens can cause dysfunction of the receptors and modulate the cytokine secreting function of immunocompetent cells. Polymorphic genes of pro-inflammatory cytokines involved in the mechanisms of defense responses of innate immunity, determine the degree of resistance to individual mycobacterial infection, as well as severity and duration of the disease in cases of clinical manifestations. The aim of the study was to investigate the connections between allelic polymorphisms of IL2, IFNG and TNFA genes and changes in secretion of the corresponding pro-inflammatory cytokines IL-2, IFNγ, and TNFα in vitro in patients with the newly diagnosed pulmonary tuberculosis (TB), depending on the clinical form of the disease.A total of 334 patients (220 men and 114 women) aged 23 to 50 years with newly diagnosed infiltrative and disseminated TB were enrolled into the study. The control group consisted of 183 healthy donors (130 men and 53 women) of corresponding age. The material of the research included DNA extracted from the whole blood and supernatants of culture suspensions of mononuclear leukocytes isolated from venous blood in healthy volunteers and patients with TB. The evaluation of cytokines secretion was performed by measuring their concentration in the blood mononuclear cell culture supernatants. using enzyme-linked immunosorbent assay (ELISA). To study polymorphic regions of cytokine genes, a polymerase chain reaction (PCR) was applied. Analysis of the obtained data was carried out by means of the program Statistica for Windows Version 6.0 (StatSoft Inc., USA).It was found that the imbalance of secretion of pro-inflammatory cytokines in TB patients was associated with the polymorphic variants of genes of these cytokines. It was found that the hypo-secretion of IL-2 is determined by the carriage of the G allele and genotype GG (T-330G) of the IL2 gene in both the control group and in patients with TB, regardless of the clinical form. In patients with DTB carriers of the homozygous genotype TT (T-330G) of the IL2gene, increased protein secretion was established. The maximum secretion of TNFб was recorded in patients with the AA genotype (G-308A) of the TNFA gene in the control group and in ITB patients; the minimum concentration of TNFα was associated with the carrier of the homozygous GG genotype (G-308A) of the TNFA gene in all the examined groups. In patients with ITB and DTB, an increase in IFNγ secretion by mononuclear blood leukocytes is not associated with the carrier of polymorphism +874A/T of the IFNG gene.Reduced secretion of IL-2 and TNFα in TB patients is associated with polymorphisms of their genes – (T-330G) of IL2 gene and (G-308A) of TNFA gene, respectively. The polymorphism (+874A/T) of the IFNG gene does not have a modulatory effect on the secretion of IFNγ in patients with TB, regardless of clinical form of the disease

Timing Constraints of In Vivo Gag Mutations during Primary HIV-1 Subtype C Infection

Background: Aiming to answer the broad question “When does mutation occur?” this study examined the time of appearance, dominance, and completeness of in vivo Gag mutations in primary HIV-1 subtype C infection. Methods: A primary HIV-1C infection cohort comprised of 8 acutely and 34 recently infected subjects were followed frequently up to 500 days post-seroconversion (p/s). Gag mutations were analyzed by employing single-genome amplification and direct sequencing. Gag mutations were determined in relation to the estimated time of seroconversion. Time of appearance, dominance, and completeness was compared for different types of in vivo Gag mutations. Results: Reverse mutations to the wild type appeared at a median (IQR) of 62 (44;139) days p/s, while escape mutations from the wild type appeared at 234 (169;326) days p/s (p<0.001). Within the subset of mutations that became dominant, reverse and escape mutations appeared at 54 (30;78) days p/s and 104 (47;198) days p/s, respectively (p<0.001). Among the mutations that reached completeness, reverse and escape mutations appeared at 54 (30;78) days p/s and 90 (44;196) days p/s, respectively (p = 0.006). Time of dominance for reverse mutations to and escape mutations from the wild type was 58 (44;105) days p/s and 219 (90;326) days p/s, respectively (p<0.001). Time of completeness for reverse and escape mutations was 152 (100;176) days p/s and 243 (101;370) days p/s, respectively (p = 0.001). Fitting a Cox proportional hazards model with frailties confirmed a significantly earlier time of appearance (hazard ratio (HR): 2.6; 95% CI: 2.3–3.0), dominance (4.8 (3.4–6.8)), and completeness (3.6 (2.3–5.5)) of reverse mutations to the wild type Gag than escape mutations from the wild type. Some complex mutational pathways in Gag included sequential series of reversions and escapes. Conclusions: The study identified the timing of different types of in vivo Gag mutations in primary HIV-1 subtype C infection in relation to the estimated time of seroconversion. Overall, the in vivo reverse mutations to the wild type occurred significantly earlier than escape mutations from the wild type. This shorter time to incidence of reverse mutations remained in the subsets of in vivo Gag mutations that reached dominance or completeness