Unusual enhancement of effective magnetic anisotropy with decreasing particle size in maghemite nanoparticles

In magnetic nanoparticles (NPs), the observed increase in the effective magnetic anisotropy Keff with the decrease in particle size D is often interpreted, sometimes unsuccessfully, using the equation Keff = Kb + (6KS/D), where Kb is the bulk-like anisotropy of the core spins and KS is the anisotropy of spins in the surface layer. Here, we test the validity of this relation in γ-Fe2O3 NPs for sizes D from 15 nm to 2.5 nm. The samples include oleic acid-coated NPs with D = 2.5, 3.4, 6.3, and 7.0 nm investigated here, with results on 14 other sizes taken from literature. Keff is determined from the analysis of the frequency dependence of the blocking temperature TB after considering the effects of interparticle interactions on TB. For the γ-Fe2O3 NPs with D \u3c 5 nm, an unusual enhancement of Keff with decreasing D, well above the magnitudes predicted by the above equation, is observed. Instead the variation of Keff vs. D is best described by an extension of the above equation by including Ksh term from spins in a shell of thickness d. Based on this core-shell-surface layer model, the data are fit to the equation Keff = Kb + (6KS/D) + Ksh{[1−(2d/D)]−3−1} with Kb = 1.9 × 105 ergs/cm3, KS = 0.035 ergs/cm2, and Ksh = 1.057 × 104 ergs/cm3 as the contribution of spins in the shell of thickness d = 1.1 nm. Significance of this result is discussed

Reversing non-local transport through a superconductor by electromagnetic excitations

Superconductors connected to normal metallic electrodes at the nanoscale provide a potential source of non-locally entangled electron pairs. Such states would arise from Cooper pairs splitting into two electrons with opposite spins tunnelling into different leads. In an actual system the detection of these processes is hindered by the elastic transmission of individual electrons between the leads, yielding an opposite contribution to the non-local conductance. Here we show that electromagnetic excitations on the superconductor can play an important role in altering the balance between these two processes, leading to a dominance of one upon the other depending on the spatial symmetry of these excitations. These findings allow to understand some intriguing recent experimental results and open the possibility to control non-local transport through a superconductor by an appropriate design of the experimental geometry.Comment: 6 pages, 3 figure

Визначення вартості інвестиційного проекту з розробки нового генеричного лікарського засобу на основі змістовного підходу

Aim. To determine the approximate cost of an investment project in developing a new medicine based on the generic type in the form of tablets taking into account the content approach in the common technical document (CTD) format of the registration dossier.Materials and methods. As materials the reports on research work in developing drugs, scientific publications, the own research and monitoring results of the pharmaceutical market of pharmaceutical company “Farmstandart” were used. The methods of generalization, systematization of the theoretical and practical material, marketing analysis, comparative and economic methods were applied.Results. The analysis and generalization of materials in determining the cost of development of new drugs has been conducted. On the example of the generic type medicine in the form of tablets in accordance with the requirements of the normative documents to the formation of the registration dossier in the CTD format the cost of the drug development and the necessary investments for each of five modules has been processed.Conclusions. The importance and necessity of determining the cost of developing a new drug as a complex product project have been substantiated. On the example of the generic type medicine in the form of tablets taking into account the requirements of normative documents the definition of the cost of development by 5 modules of the registration dossier has been worked out.Цель: определение ориентировочной стоимости инвестиционного проекта по разработке нового лекарственного средства (ЛС) по типу генерического в форме таблеток на основе содержательного подхода в общем техническом документе (ОТД) формата регистрационного досье.Материалы и методы. В качестве материалов использовали отчеты о выполненных научно-исследовательских работах по разработке ЛС, научные публикации, собственные исследования и результаты мониторинга розничного рынка лекарств компании «Фармстандарт»; методы: обобщения, систематизации теоретического и практического материала, маркетингового анализа, сравнительный и экономический.Результаты исследований. Проведен анализ и обобщение материалов по определению стоимости разработки новых ЛС. На примере ЛС генерического типа в форме таблеток согласно требованиям нормативных документов к формированию регистрационного досье в ОТД-формате обработаны стоимость разработок ЛС и необходимые инвестиции по каждому из пяти модулей.Выводы. Обоснована важность и необходимость определения стоимости разработки нового ЛС как комплексного продуктового проекта. На примере ЛС генерического типа в форме таблеток с учетом требований нормативных документов обработаны определения стоимости разработки по 5 модулям регистрационного досье.Мета: визначення орієнтовної вартості інвестиційного проекту з розробки нового лікарського засобу (ЛЗ) за типом генеричного у формі таблеток на основі змістовного підходу в загальному технічному документі (ЗТД) формату реєстраційного досьє.Матеріали та методи: як матеріали використовували звіти про виконані науково-дослідні роботи з розробки ЛЗ, наукові публікації, власні дослідження та результати моніторингу роздрібного ринку ліків компанії «Фармстандарт»; методи: узагальнення, систематизації теоретичного і практичного матеріалу, маркетингового аналізу, порівняльний та економічний.Результати досліджень. Проведено аналіз та узагальнення матеріалів щодо визначення вартості розробки нових ЛЗ. На прикладі ЛЗ генеричного типу у формі таблеток згідно з вимогами нормативних документів до формування реєстраційного досьє у ЗТД-форматі опрацьовано вартість розробок ЛЗ та необхідні інвестиції за кожним із п’яти модулів.Висновки. Обґрунтована важливість і необхідність визначення вартості розробки нового ЛЗ як комплексного продуктового проекту. На прикладі ЛЗ генеричного типу у формі таблеток з урахуванням вимог нормативних документів опрацьовано визначення вартості розробки за 5 модулями реєстраційного досьє

Overexpression of the RNA-binding protein HuR impairs tumor growth in triple negative breast cancer associated with deficient angiogenesis [abstract]

Breast cancer is the second most common cancer in women and causes the death of 519,000 people worldwide. Many cancer genes are posttranscriptionally regulated by RNA-binding proteins (RBPs) and microRNAs. The RBP HuR binds to the AU-rich (ARE) regions of labile mRNAs, such as proto-oncogenes, stabilizing their mRNA and facilitating their translation into protein. HuR has been described to control genes in multiple areas of the acquired capabilities model of cancer and has been hypothesized to be a tumor maintenance gene, allowing for cancers to proliferate once they are established. We investigated the role of HuR in aggressive and difficult to treat triple-negative breast cancer

Применение магнитных сорбентов, модифицированных молекулярно импринтированными полимерами, для скрининга фенольных ксеноэстрогенов

A new method for the determining phenolic xenoestrogens, chemicals that destroy the endocrine system (EDC), i.e., 4-octylphenol (OP), 4-nonylphenol (NLP) and bisphenol A (BPA), in sediments and river waters with preliminary concentration on magnetic sorbents functionalized by polymers based on molecular imprints is proposed. were determined In the concentrates EDC were converted to derivatives by reaction with acetic anhydride and then determined by gas chromatography in combination with mass spectrometry (GC-MS). The accuracy of the determination was evaluated by the "added–found" method.Use of the molecular imprinted polymers allows determining up to 5 ng/l NLP and 6 ng/l OP and BFA in wastewaters. In bottom sediments, the limit of determination was 100 ng/kg for NLP and 150 ng/kg for OP or BPA. The decrease in sensitivity was due to the high contamination of bottom sediments and increased matrix effects. Products of degradation of humic acid, surfactants and petroleum products have the greatest interfering effect. The method was tested on EDC screening in waters and bottom sediments of the Voronezh reservoir. Sites near the unorganized discharge of wastewaters and near the discharge of municipal wastewater treatment plants were selected as sampling points. The maximum concentrations of OP, NLP and BPA found in the river waters were 335, 1138 and 144 ng/l, respectively, and in the bottom sediments were 6.9, 10.7 and 5.9 μg/kg, respectively.Keywords: phenolic xenoestrogenes, bisphenol A, 4-octylphenol, 4-nonylphenol, concentration, molecularly imprinted polymers, determinationПредложен способ определения фенольных ксеноэстрогенов – химических веществ, разрушающих эндокринную систему (EDC): 4-октилфенола (ОФ), 4-нонилфенола (НЛФ) и бисфенола А (БФА) в донных отложениях и речных водах с предварительным концентрированием на магнитных сорбентах, функционализированных полимерами с молекулярными отпечатками. В концентратах EDC переводили в дериваты по реакции с уксусным ангидридом, которые определяли методом газовой хроматографии в сочетании с масс-спектрометрией (ГХ-МС). Правильность определения оценивали методом «введено-найдено».Применение молекулярно импринтированных полимеров позволяет определить в сточной воде до 5 нг/л НЛФ и по 6 нг/л ОФ и БФА. В донных отложениях предел определения на порядок хуже и составляет 100 нг/кг (НЛФ) и по 150 нг/кг (ОФ, БФА). Уменьшение чувствительности обусловлено высокой загрязненностью донных отложений и усилением матричных эффектов. Наибольшее мешающее влияние оказывают примеси продуктов деградации гуминовых кислот, ПАВ и нефтепродукты. Способ апробирован на примере скрининга EDC в водах и донных отложениях Воронежского водохранилища. В качестве точек отбора выбраны участки вблизи неорганизованного сброса неочищенных сточных вод и вблизи сброса сточных вод городских очистных сооружений. Установлено максимальное содержание в речных водах 340, 1140 и 140 нг/л и в донных отложениях – 6.9, 10.7 и 5.8 мкг/кг соответственно ОФ, НЛФ, БФА. Ключевые слова: фенольные ксеноэстрогены, бисфенол А, 4-октилфенол, 4-нонилфенол, концентрирование, молекулярно импринтированные полимеры, определени

Effects of habitat and land use on breeding season density of male Asian Houbara Chlamydotis macqueenii

Landscape-scale habitat and land-use influences on Asian Houbara Chlamydotis macqueenii (IUCN Vulnerable) remain unstudied, while estimating numbers of this cryptic, low-density, over-hunted species is challenging. In spring 2013, male houbara were recorded at 231 point counts, conducted twice, across a gradient of sheep density and shrub assemblages within 14,300 km² of the Kyzylkum Desert, Uzbekistan. Four sets of models related male abundance to: (1) vegetation structure (shrub height and substrate); (2) shrub assemblage; (3) shrub species composition (multidimensional scaling); (4) remote-sensed derived land-cover (GLOBCOVER, 4 variables). Each set also incorporated measures of landscape rugosity and sheep density. For each set, multi-model inference was applied to generalised linear mixed models of visit-specific counts that included important detectability covariates and point ID as a random effect. Vegetation structure received strongest support, followed by shrub species composition and shrub assemblage, with weakest support for the GLOBCOVER model set. Male houbara numbers were greater with lower mean shrub height, more gravel and flatter surfaces, but were unaffected by sheep density. Male density (mean 0.14 km-2, 95% CI, 0.12‒0.15) estimated by distance analysis differed substantially among shrub assemblages, being highest in vegetation dominated by Salsola rigida (0.22 [CI, 0.20‒0.25]), high in areas of S. arbuscula and Astragalus (0.14 [CI, 0.13‒0.16] and 0.15 [CI, 0.14‒0.17] respectively), lower (0.09 [CI, 0.08‒0.10]) in Artemisia and lowest (0.04 [CI, 0.04‒0.05]) in Calligonum. The study area was estimated to hold 1,824 males (CI: 1,645‒2,030). The spatial distribution of relative male houbara abundance, predicted from vegetation structure models, had the strongest correspondence with observed numbers in both model-calibration and the subsequent year’s data. We found no effect of pastoralism on male distribution but potential effects on nesting females are unknown. Density differences among shrub communities suggest extrapolation to estimate country- or range-wide population size must take account of vegetation composition

A Novel Approach of Synchronization of Microgrid with a Power System of Limited Capacity

Currently, active networks called microgrids are formed on the basis of local power supply systems with a small share of distributed generation. Microgrids operating in an island mode, in some cases, have the ability to transfer electricity excess to an external network leading to a synchronization requirement; thus, the optimization task in terms of the system’s synchronization must be considered. This paper proposes a method for obtaining synchronization between microgrids and power systems of limited capacity based on a passive synchronization algorithm, allowing us to connect a microgrid to an external power system with a minimum impact moment on the shaft of the generating equipment. The algorithm application was demonstrated by considering a real-life object in Tajikistan. The simulation was carried out on RastrWin3. The obtained results show that the microgrid generator is connected to an external power system at an angle of 0.3◦ and a power surge of 29 kW, unlike the classical synchronization algorithm with an angle of 6.8◦ and a power surge of 154 kW (a reduction of the shock moment by more than five times). The proposed synchronization method allows us to reduce the resource consumption of the generating equipment and increase the reliability and efficiency of the functioning units of the examined power system. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

A Molecular Platinum Cluster Junction: A Single-Molecule Switch

We present a theoretical study of the electronic transport through single-molecule junctions incorporating a Pt6 metal cluster bound within an organic framework. We show that the insertion of this molecule between a pair of electrodes leads to a fully atomically engineered nano-metallic device with high conductance at the Fermi level and two sequential high on/off switching states. The origin of this property can be traced back to the existence of a HOMO which consists of two degenerate and asymmetric orbitals, lying close in energy to the Fermi level of the metallic leads. Their degeneracy is broken when the molecule is contacted to the leads, giving rise to two resonances which become pinned close to the Fermi level and display destructive interference.Comment: 4 pages, 4 figures. Reprinted (adapted) with permission from J. Am. Chem. Soc., 2013, 135 (6), 2052. Copyright 2013 American Chemical Societ