Observation of asymmetric spectrum broadening induced by silver nanoparticles in a heavy-metal oxide glass

We demonstrate experimentally and support by a theoretical analysis an effect of asymmetric spectrum broadening, which results from doping of silver nanoparticles into a heavy-glass matrix, 90(0.5WO3-0.3SbPO4-0.2PbO)-10AgCl. The strong dispersion of the effective nonlinear coefficient of the composite significantly influences the spectral broadening via the self-phase modulation, and leads to a blue upshift of the spectrum. Further extension of the spectrum towards shorter wavelengths is suppressed by a growing loss caused by the plasmon resonance in the silver particles. The red-edge spectral broadening is dominated by the stimulated Raman Scattering.Comment: Accepted for publishing epl13477; EPL Journal 201

Coherent spin relaxation in molecular magnets

Numerical modelling of coherent spin relaxation in nanomagnets, formed by magnetic molecules of high spins, is accomplished. Such a coherent spin dynamics can be realized in the presence of a resonant electric circuit coupled to the magnet. Computer simulations for a system of a large number of interacting spins is an efficient tool for studying the microscopic properties of such systems. Coherent spin relaxation is an ultrafast process, with the relaxation time that can be an order shorter than the transverse spin dephasing time. The influence of different system parameters on the relaxation process is analysed. The role of the sample geometry on the spin relaxation is investigated.Comment: Latex file, 22 pages, 7 figure

Morphological verification of the first missed abortion

Objective. The study aimed to compare the level of INF a2 immunoexpression in tissues obtained during medical abortion with the corresponding level of IFNa2 expression in a retained fetal egg tissues after the first missed abortion. The authors compared the anamnestic data on previous inflammatory diseases of the genital tract with the results of an extended morphological study of the material obtained during the evacuation of the contents of the uterine cavity during the first non-developing pregnancy in the first trimester.Materials and methods. The study included 15 patients with first-time missed abortions caused by a viral infection (6-8 weeks of pregnancy). All patients demonstrated either recurrent herpes simplex labialis/genitalis or PCR confirmed HSV, HPV, CMV. Exclusion criteria were recurrent miscarriage, blighted ovum, endocrinopathies, male factor infertility, and other causes of miscarriage. The comparison group included 20 women of the same age that chose to undergo a medical abortion.Results. In patients from the comparison group, the main producer of IFN a2 was syncytiotrophoblast as well as maternal decidual cells in the parietal endometrium and uteroplacental area. In the main group, manifested hematogenous infection (microabscesses, vasculitis, lymphocytic and macrophage infiltration) with dystrophy and necrosis of decidual maternal cells and secondary pathological changes in the placental villi were diagnosed, which led to a significant decrease in the IFN a2 immunoexpression in all the studied cells.Conclusion. The lack of anamnestic data on previous urogenital infections does not exclude the etiological role of the inflammatory component in the genesis of non-developing pregnancy. First-time occurred pregnancy loss requires adequate postoperative interferon therapy and a thorough examination of a couple

Comparative morphological characteristics of the uteroplacental area in abnormal placentation

The aim. To carry out a comparative morphological characteristic of the uteroplacental area with abnormal placentation – pl. accreta, pl. increta, pl. percreta. Materials and methods. The study included 47 patients with atypical placentation; the comparison group included 10 healthy pregnant women with uterine scar after a previous caesarean section. A histological study of uteroplacental area samples was performed with hematoxylin and eosin, methylene blue staining. An immunohistochemical study with primary antibodies to cytokeratin 7 (CK7), Hif2a, vascular endothelial growth factor, α-SMA was carried out. The differences between the compared values were considered to be statistically significant at p < 0.05. The results of the study. Pl. accreta was determined in 12 (25.5 %), pl. increta – in 30 (63.9 %), pl. percreta – in 5 (10.6 %) patients. In all patients of the main group, the decidua was completely or partially absent in the area of abnormal placentation or was replaced by an uneven layer of fetal fibrinoid. Cases when placental villi unevenly penetrated into the thickness of myometrium in the form of “tongues” or “coves” bordered by fetal fibrinoid and often located intermuscularly were defined as pl. increta (n = 26). Cases with the placental villi ingrowth to the serous membrane were considered as pl.  percreta (n  =  5). In cases with deep variants of  ingrowth (pl. increta and pl. percreta) (n = 31), the villi were visualized in the lumen of the vessels and the thinning of the lower uterine segment with the presence of stretched muscle bundles was revealed. Aseptic necrosis of  the myometrium was  found: in 2 (16.7 %) of 12 women with pl. accreta, in 26 (86.7 %) of 30 women with pl. increta and in 5 (100 %) women with pl. percreta. There were no areas of necrosis in the myometrium of the women of comparison group. Conclusion. The appearance and increase of myometrial necrosis zones in response to an increase in the depth of placental villus ingrowth were detected. Myometrial necrosis zones could be the cause of activation of angiogenic factors and an important stimulus for the development of abnormal vascularization in placenta accreta spectrum

Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters

ВОЗМОЖНОСТИ ДИФФУЗИОННО-ВЗВЕШЕННЫХ ИЗОБРАЖЕНИЙ В ДИФФЕРЕНЦИАЛЬНОЙ ДИАГНОСТИКЕ ЗЛОКАЧЕСТВЕННОЙ И ДОБРОКАЧЕСТВЕННОЙ МЕДИАСТИНАЛЬНОЙ ЛИМФАДЕНОПАТИИ

Introduction. Mediastinal lymphadenopathy can be caused by a wide range of benign and malignant states. Determination of the genesis of lymphadenopathy is crucial for treatment planning and prognosis of the disease.The purpose of the study was to evaluate the diagnostic accuracy of diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurements in differentiating malignant versus benign mediastinal lymphadenopathy. Material and Methods. 48 consecutive patients with at least one enlarged mediastinal lymph node revealed on CT-scans were examined on 1,5 T MR-machine with conventional images and respiratory-triggered DWI. In all patients one of the biggest solid lymph nodes was selected for ADC measurements and mean ADCs of each node were recorded. ADCs were correlated with the results of complete diagnostic work-up (including histopathological diagnosis in 41 patients) and follow-up CT. Statistics included Student’s t-test, Mann-Whitney U-test and ROC-curve analysis. Results. 27 lymph nodes were classified as malignant (metastases, lymphoma) and 21 lymph nodes were classified as benign (sarcoidosis, reactive hyperplasia, tuberculosis). Mean ADC of malignant lymph nodes (1,02 ± 0,29×10−3 mm2/s) was significantly lower than that of benign lymph nodes (1,57 ± 0,32×10−3 mm2/s), p<0,0001. The cut-off value of ≤1,3×10−3mm2/s for ADC indicated the malignancy with a sensitivity of 81,5 % and a specificity of 85,7%. The area under the ROC-curve was 0,89 (95 % confidence interval: 0,77, 0,96), p<0,0001. Conclusion. DWI is a promising technique in chest pathology. DWI with ADC measurements could be used as a good complementary tool in the diagnostic work-up of patients with mediastinal lymphadenopathy.Введение. Медиастинальная лимфаденопатия может быть обусловлена широким спектром доброкачественных и злокачественных заболеваний. Определение характера лимфаденопатии играет ключевую роль в выборе тактики лечения и оценке прогноза заболевания. Цель исследования – изучить возможности диффузионно-взвешенных изображений (ДВИ) с оценкой измеряемого коэффициента диффузии (ИКД) в дифференциальной диагностике злокачественных и доброкачественных форм медиастинальной лимфаденопатии. Материал и методы. В исследование включено 48 пациентов с наличием как минимум одного увеличенного медиастинального лимфоузла по результатам компьютерной томографии. Исследование проводилось на магнитно-резонансном томографе с напряженностью поля 1,5 Тл с получением традиционных изображений и синхронизированных с дыханием ДВИ. У каждого пациента выбирался один из наиболее крупных солидных лимфоузлов, в котором оценивалось среднее значение ИКД. Значения ИКД сравнивались с результатами гистологического исследования (у 41 пациента), комплексного клинико-лучевого обследования и динамического наблюдения. Для статистической обработки результатов исследования использовались t-критерий Стьюдента, U-критерий Манна – Уитни, ROC-анализ. Результаты. У 27 пациентов установлено злокачественное поражение лимфоузлов (метастазы, лимфома), у 21 – доброкачественные изменения (саркоидоз, реактивная гиперплазия, туберкулез). Среднее значение ИКД при злокачественной лимфаденопатии (1,02 ± 0,29×10−3 мм2/с) оказалось ниже, чем при доброкачественной (1,57 ± 0,32×10−3 мм2/с), отличия статистически значимы (p<0,0001). Пороговое значение ИКД, составившее ≤1,3×10−3 мм2/с (95 % доверительный интервал: 1,06; 1,64), позволило выявлять злокачественное поражение лимфоузлов с чувствительностью 81,5 % и специфичностью 85,7 %; площадь под ROC-кривой составила 0,89 (95 % доверительный интервал: 0,77; 0,96), р<0,0001. Заключение. ДВИ являются перспективным методом лучевой диагностики патологии органов грудной клетки. ДВИ с оценкой ИКД могут быть использованы в качестве дополнительной методики в комплексном обследовании пациентов с медиастинальной лимфаденопатией

Измерение разности назальных потенциалов — новый, информативный тест для диагностики муковисцидоза

An attempt was undertaken to evaluate peculiarities of biophysical phenotype of the basic cystic fibrosis (CF) defect in 21 cystic fibrosis patients from 5 to 41 years old. CF patients have demonstrated markedly more negative potential difference (NPD) across nasal epithelium than 15 patients of non-CF control group. The mean NPD of C F patients was 44.7±2.2 mV (range -32.5 to -68.9 mV), in the control group it was 17.2±1.8 mV. The method of the nasal PD measuring is acceptable and rapidly performed and may provide an additional tool for CF diagnosing.Была предпринята попытка оценить особенности биофизического фенотипа основного дефекта муковисцидоза у 21 больного в возрасте от 5 лет до 41 года. У лиц, страдающих муковисцидозом, были получены более выраженные отрицательные величины разности назальных потенциалов (nasal Potential Difference — NPD), чем у больных, страдающих хроническими неспецифическими заболеваниями легких (ХНЗЛ) контрольной группы. Средние значения NPD в группе больных муковисцидозом составили -44,7±2,2 мВ (от-32,5 мВ до -68,9 мВ), в контрольной группе -17,2±1,8 мВ (от-6,8 мВ до -30,2 мВ). Метод измерения NPD является легко и быстро выполнимым, может быть рекомендован в качестве дополнительного теста для диагностики муковисцидоза

ДИФФЕРЕНЦИАЛЬНАЯ ДИАГНОСТИКА МЕДИАСТИНАЛЬНОЙ ЛИМФАДЕНОПАТИИ ПРИ ЛИМФОМЕ И САРКОИДОЗЕ С ПОМОЩЬЮ ДИФФУЗИОННО-ВЗВЕШЕННОЙ МАГНИТНО-РЕЗОНАНСНОЙ ТОМОГРАФИИ

The aim of the study. Investigation of the potential of diffusion-weighted magnetic resonance imaging (DW-MRI) with apparent diffusion coefficient (ADC) evaluation for differential diagnosis of mediastinal lymphadenopathy in lymphoma and sarcoidosis.Materials and methods. The study included 15 patients with sarcoidosis and 7 patients with lymphoma. In each patient ADC values of 3 largest lymph nodes were measured.Results. Differences of mean ADC values in lymphoma (1,01±0,3×10-3mm2/s) and sarcoidosis (1,51±0,25×10-3mm2/s) were significant, p<0,0001. Optimal cut-point value for ADC of ≤1,1×10-3mm2/s differentiated lymphoma from sarcoidosis with sensitivity of 76,2%, specificity of 97,8% and accuracy of 90,9%, the area under the ROC-curve was 0,89.Conclusion. Preliminary results of the study have demonstrated the potential of DW-MRI in differential diagnosis of lymphoma and sarcoidosis and expediency of the further study.Цель. Изучение возможностей диффузионно-взвешенной магнитно-резонансной томографии (ДВ-МРТ) грудной клетки с оценкой измеряемого коэффициента диффузии (ИКД) в дифференциальной диагностике медиастинальной лимфаденопатии при лимфоме и  саркоидозе.Материалы и методы. В исследование включены 15 пациентов с саркоидозом и 7  пациентов с лимфомой. У каждого пациента значения ИКД измерены в трех наиболее  крупных лимфатических узлах.Результаты. Выявлены значимые отличия средних значений ИКД при лимфоме (1,01±0,3×10-3 мм2/с) и саркоидозе (1,51±0,25×10-3 мм2/с), p<0,0001. При использовании порогового значения ИКД ≤1,1×10-3 мм2/с чувствительность, специфичность и точность метода в дифференциальной диагностике лимфомы и саркоидоза составили 76,2; 97,8 и  90,9% соответственно, площадь под ROC-кривой — 0,89.Заключение. Предварительные результаты показали высокую информативность ДВ-МРТ в дифференциальной диагностике лимфомы и саркоидоза и целесообразность продолжения исследования

Nonlinear Spin Dynamics in Nuclear Magnets

A method is developed for solving nonlinear systems of differential, or integrodifferential, equations with stochastic fields. The method makes it possible to give an accurate solution for an interesting physical problem: What are the peculiarities of nonlinear spin dynamics in nonequilibrium nuclear magnets coupled with a resonator? Evolution equations for nuclear spins are derived basing on a Hamiltonian with dipole interactions. The ensemble of spins is coupled with a resonator electric circuit. Seven types of main relaxation regimes are found: free induction, collective induction, free relaxation, collective relaxation, weak superradiance, pure superradiance, and triggered superradiance. The initial motion of spins can be originated by two reasons, either by an imposed initial coherence or by local spin fluctuations due to nonsecular dipole interactions. The relaxation regimes caused by the second reason cannot be described by the Bloch equations. Numerical estimates show good agreement with experiment.Comment: 1 file, 47 pages, LaTe

Monochromatic electron photoemission from diamondoid monolayers

We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68percent of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flatpanel displays