Observation of enhanced transmission for s-polarized light through a subwavelength slit

Enhanced optical transmission (EOT) through subwavelength apertures is usually obtained for p-polarized light. The present study experimentally investigates EOT for s-polarized light. A subwavelength slit surrounded on each side by periodic grooves has been fabricated in a gold film and covered by a thin dielectric layer. The excitation of s-polarized dielectric waveguide modes inside the dielectric film strongly increases the s-polarized transmission. Transmission measurements are compared with a coupled mode model and show good qualitative agreement. Adding a waveguide can improve light transmission through subwavelength apertures, as both s and p-polarization can be efficiently transmitted.Comment: 11 pages, 3 figures, submitted to Applied Physics Letter

Giant volume magnetostriction in the Y 2

An investigation of the Y2Fe17 compound belonging to the class of intermetallic alloys of rare-earth and 3d-transition metals is presented. The magnetization, magnetostriction, and thermal expansion of the Y2Fe17 single crystal were studied. The forced magnetostriction and magnetostriction constants were investigated in the temperature range of the magnetic ordering close to the room temperature. The giant field induced volume magnetostriction was discovered in the room temperature region in the magnetic field up to 1.2 T. The contributions of both anisotropic single-ion and isotropic pair exchange interactions to the volume magnetostriction and magnetostriction constants were determined. The experimental results were interpreted within the framework of the Standard Theory of Magnetostriction and the Landau thermodynamic theory. It was found out that the giant values of the volume magnetostriction were caused by the strong dependence of the 3d-electron Coulomb charge repulsion on the deformations and width of the 3d-electron energy band

Klotho protein in men with type 2 diabetes mellitus blood and its association with cardiometabolic risk factors

The aim of the study was to investigate Klotho protein levels in men with type 2 diabetes blood and its associations with several cardiometabolic risk factors. Material and methods. The study included 37 men with diabetes and 141 men without diabetes. Fasting blood samples were collected to measure Klotho protein levels and some biochemical parameters. Results and its discussion. The Klotho protein level in men with diabetes was significantly lower than in men without diabetes (374 [117; 500] and 515 [315; 1009] pg/dl, p<0.0001). Among the examined men with diabetes with a glomerular filtration rate of less than 60 ml/min/1.73 cm2, the concentration of Klotho protein was 4 times lower than in the comparison group (104 [93; 118] and 413 [147; 535] pg/dl, p = 0.014) In men with diabetes, the Klotho protein was inversely correlated with the ratio of waist to hip circumference (-0.329; p = 0.047). But with multivariate analysis, only a tendency towards a negative association of the Klotho protein with abdominal obesity was determined (-0.385, p = 0.078). Conclusion. The content of Klotho protein in men with diabetes is significantly lower, especially in middle-aged men and in those with a reduced glomerular filtration rate. In men with diabetes, the Klotho protein has a negative correlation with the presence of abdominal obesity. In a multivariate analysis among men with diabetes, the Klotho protein tends to be inversely associated with the presence of abdominal obesity

Молекулярно-биологические особенности анапластических астроцитом и выделение молекулярных подгрупп их IDH1-мутантных форм с помощью анализа in silico

Aim. The problem of anaplastic astrocytomas is quite relevant today. The WHO classification distinguishes IDH1/IDH2 mutant anaplastic astrocytomas, anaplastic astrocytomas without IDH1/IDH2 mutations, and anaplastic astrocytomas not otherwise specified. The aim of this work was to cluster IDH1-mutant anaplastic astrocytomas based on their cytogenetic profile to select prognostically significant molecular subgroups, which can have both clinical and fundamental scientific value.Materials and methods. In this work, we performed a cluster analysis of anaplastic astrocytomas according to their cytogenetic profiles based on available genetic databases of tumors and large cohort studies, as well as a comparison of Kaplan – Meyer survival curves for various molecular subgroups of patients.Results. We studied the main genetic features of the inter-tumor heterogeneity of anaplastic astrocytomas and distinguished seven molecular subgroups based on the cytogenetic profile: embryo-like, inflammatory-like, deletion, matrix, cyclin, GATA3-dependent and tyrosine kinase. Moreover, each of these subgroups has not only distinctive molecular characteristics, but also important clinical features.Conclusion. A detailed study of the molecular properties of anaplastic astrocytomas will not only optimize the process for predicting treatment outcomes, but also create innovative formats for targeted therapy within the framework of the concept of personalized medicine.Актуальность. Проблема анапластических астроцитом достаточно актуальна в наши дни. В классификации Всемирной организации здравоохранения выделяются анапластическая астроцитома с мутацией в генах IDH1 и IDH2, анапластическая астроцитома без мутаций в генах IDH1 и IDH2, анапластическая астроцитома без дополнительного генетического уточнения.Целью данной работы стало кластерирование анапластических астроцитом с мутацией в гене IDH1 на основе их цитогенетического профиля для выделения прогностически значимых молекулярных подгрупп, которые могут иметь как клинико-практическое, так и фундаментально-научное значение. Проведен кластерный анализ анапластических астроцитом по их цитогенетическим профилям на основе доступных генетических баз данных опухолей и крупных когортных исследований, а также сравнение кривых  выживаемости Каплана – Мейера для различных молекулярных подгрупп пациентов.Результаты. Нам удалось изучить основные генетические особенности межопухолевой гетерогенности анапластических астроцитом и выделить на основе цитогенетического профиля семь молекулярных подгрупп – эмбриональноподобную, инфламмоподобную, делеционную, матриксную, циклиновую, GATA3-зависимую и тирозинкиназную. При этом каждая из этих подгрупп имеет не только отличительные молекулярные характеристики, но и важные клинические особенности.Заключение. Детальное изучение молекулярных свойств анапластических астроцитом позволит не только оптимизировать процесс прогнозирования исходов лечения, но и создать инновационные форматы для таргетной терапии в рамках концепции персонализированной медицины

Oblique launching of optical surface waves by a subwavelength slit

The electromagnetic field on the metal surface launched by a subwavelength slit is analytically studied, for the case when the fundamental mode inside the slit has a wavevector component along the slit axis (conical mount). Both near-field and far-field regions are discussed, and the role of surface plasmon-polaritons and Norton waves is revealed. It is shown that the distance from the slit at which NW are more intense than surface plasmons decrease with parallel wavevector, which could help experimental studies on Norton waves. Additionally, it is found that the s-polarization component, while present for any non-zero parallel wavevector, only weakly contributes to the NWs.Comment: 8 pages, 5 figure

Resonance effects due to the excitation of surface Josephson plasma waves in layered superconductors

We analytically examine the excitation of surface Josephson plasma waves (SJPWs) in periodically-modulated layered superconductors. We show that the absorption of the incident electromagnetic wave can be substantially increased, for certain incident angles, due to the resonance excitation of SJPWs. The absorption increase is accompanied by the decrease of the specular reflection. Moreover, we find the physical conditions guaranteeing the total absorption (and total suppression of the specular reflection). These conditions can be realized for Bi2212 superconductor films.Comment: 17 pages, 3 figure

Study of influence of aluminum nitride nanoparticles on the structure, phase composition and mechanical properties of AZ91 alloy

In this work, magnesium-based composites were obtained by shock-wave compaction of a powder mixture of Mg-5 wt.% AlN at a shock-wave pressure of 2 GPa. Their microstructure was investigated and the phase composition was determined, from which it follows that the nanoparticles retain their phase composition and are uniformly distributed in the magnesium matrix. The materials obtained by shock-wave compaction were used as master alloys for the production of magnesium alloys by die casting. The amount of aluminum nitride nanoparticles in the AZ91 magnesium alloy was 0.5 wt.%. Studies of the microstructure of the magnesium alloys showed a decrease in the average grain size of the magnesium matrix from 610 to 420 m. Studies of mechanical properties have shown that the introduction of aluminum nitride nanoparticles increases the yield strength from 55 to 119 MPa, the tensile strength from 122 to 171 MPa and the plasticity from 4 to 6.5%, respectively. The effect of nanoparticles on the fracture behavior of the magnesium alloy under tension was determine