Effect of an electric field on a floating lipid bilayer: a neutron reflectivity study

We present here a neutron reflectivity study of the influence of an alternative electric field on a supported phospholipid double bilayer. We report for the first time a reproducible increase of the fluctuation amplitude leading to the complete unbinding of the floating bilayer. Results are in good agreement with a semi-quantitative interpretation in terms of negative electrostatic surface tension.Comment: 12 pages, 7 figures, 1 table accepted for publication in European Physical Journal E Replaced with with correct bibliograph

Study of influence of heat stress on some physiological and productive traits in Holstein-Friesian dairy cows

Received: October 6th, 2020 ; Accepted: February 1st, 2021 ; Published: March 18th, 2021 ; Correspondence: [email protected] aim of the research was to study the effect of heat stress (HS) on some physiological and productive traits in Holstein-Friesian dairy cows. The study included 22 cows on different parities. In the building where the cows were housed, the temperature-humidity index (THI) was reported at 10:00 and 15:00 h, at the same time the rectal temperature (RT) and respiratory rate (RR) were reported for each of the examined cows. The daily rumen activity was taken from the SCR system by Allflex. The average THI values in May were 71, in June - 75, in July - 74, and in August - 77, from which it follows that in the summer months the cows were in conditions of mild to moderate heat stress throughout the day. The average daily milk yield of the cows increased from May to June and reached 41.44 kg day-1 , then decreased in July and August to 37.2 and 32.48 kg day-1 , respectively. With an increase in the THI values, an increase in the RR and RT was registered, as in THI above 79 the RR was 56.54 per min, and the RT was 39.33 °C. With increasing the THI values, the rumination of the cows decreased from 563 per day at THI < 72 to 542.5 at THI > 79. In cows with high daily milk yield, a higher RT was registered, and in cows with more than 50 kg per day, the RT was 39.09 °С. A more intense rumination was found in cows with higher daily milk yield. In cows with an average daily milk yield of 33.26 kg, an average of 450 ruminations per day were reported, and in those with an average milk yield of up to 42.89 kg - 650 ruminations per day. From the research conducted it was found that the studied physiological traits - rectal temperature, respiration rate and rumination are influenced by HS and the intensity of this effect depend on the daily milk yield of cows and THI levels

Simultaneous Refractive Index Sensing Using an Array of Suspended Porous Silicon Membranes

We propose a fast and cost-effective method for obtaining a miniaturized array-formatted sensor suitable for multiplexed detection. Our solution is based on the fabrication of multiple µm-sized suspended porous silicon (PSi) membranes working as independent transducers. Our process can potentially integrate an array of up to 1000 sensing spots per cm2 . We also propose a simple and user-friendly optical platform to simultaneously interrogate each element of the array in real-time. The feasibility of this idea was proved performing several sensing experiments where we were able to detect refractive index (RI) variations with different transducers at the same time. An average experimental sensitivity of 685 nm/RIU (Refractive Index Unit) was achieved, with a theoretical limit of detection (LoD) of 10-5 RIU. The analyzed sensing spots displayed similar behavior both in time and in magnitude. We believe that the high capabilities of the sensor presented in this work, along with the sensing mechanism, can be very useful for multi-parametric analysis and multi-target detection of biological samples

Raman study of self-assembled InAs/InP quantum wire stacks with varying spacer thickness

Self-assembled InAs/InP (001) quantum wire stacks have been investigated by means of Raman scattering. The characteristics of the observed vibrational modes show clear evidence of confinement and atomic intermixing between As and P atoms from the wire and the spacer. The change in the intermixing with spacer layer thickness and growth temperature is investigated. Likewise, the effect of annealing on the exchange of As and P atoms is also studied. Resonance effects in confined and interface phonons are discussed for excitation in the vicinity of the InAs E1 critical point. Finally, the energy of the interface modes is related to the structural characteristics of the wires by comparing the experimental data with a lattice dynamic calculation based on the dielectric continuum [email protected] [email protected] [email protected]

On fatigue behaviour of two spring steels. Part II: Mathematical models

Symmetric fatigue in two spring steels is investigated in three groups of specimens. One of the groups (Steel EN10270-1SH/ DIN 17223C – C 0.82%, Mn 0.76%, Si 0.26%) has experienced rotating-bending fatigue in air, and the other two groups (Steel BS250A53/ DIN 55Si7 – C 0.56%, Mn 0.81%, Si 1.85%), torsion fatigue in-air and corrosion environment. All experiments include testing to fracture, applying acetate-foil replication technique, replica monitoring of short crack surface growth, length measuring of propagating cracks, a, at the corresponding number of fatigue cycles, N. Data obtained from replica monitoring are presented in plots “Crack lengths, a – Cycles, N”, and used for calculating fatigue crack growth rates, da/dN, and graphical presentations “Crack growth rates, da/dN – Crack lengths, a”. A mathematical description of da/dN – a is presented by introducing a parabolic-linear model in different versions for each of the steels. The model versions are verified through comparing the experimental fatigue lifetimes with those calculated by the proposed model version

On fatigue behavior of two spring steels. Part I: Wöhler curves and fractured surfaces

Symmetric fatigue in two spring steels is investigated in three groups of specimens. One of the groups (Steel EN10270-1SH/ DIN 17223C – C 0.82%, Mn 0.76%, Si 0.26%) has experienced rotating-bending fatigue in air, and the other two groups (Steel BS250A53/ DIN 55Si7 – C 0.56%, Mn 0.81%, Si 1.85%), torsion fatigue in-air and corrosion environment. Fatigue life-time data are obtained for both spring steels, and their corresponding Wöhler curves plotted and mathematically described. Surface short fatigue cracks are observed from origin to fracture by using acetate-foil replication technique, and their length, a, measured at the corresponding number of fatigue cycles, N. Those data are presented in plots “Crack lengths, a – Cycles, N” and a comparison made between both the steels. The fractured surfaces of all specimens have been studied and analyzed by the scanning-electron microscopy method

Развитие профессионализма педагога в области организации инклюзивного образования в школе (опыт России и Болгарии)

The aim of the investigation is to discuss the problems connected with a current state of inclusive education in Russia and Bulgaria. Methods. Experience, positive and negative tendencies in the field of inclusive education of the Russian and Bulgarian systems of training and education are analysed and generalized.Results and scientific novelty. Creating conditions for quality education for all children regardless of the characteristics of their health is a social guarantee of any post-industrial country. Access to quality education for children with disabilities is a target of nowadays reforms of the Russian and Bulgarian education in the context of globalization: Bulgaria’s accession to the European Union and activity of Russia as an independent state on the international education arena. Adverse conditions of inclusive education in the two countries complicate establishing and implementation of public policies for the development of inclusive education. However, objective data about teachers’ readiness for the implementation of inclusive education and public debate around this issue stimulates a better understanding of the principles on which the activities of the teacher, directed at the education of children with disabilities. The principles providing a basis for developing professional teacher competencies in the field of inclusive education are presented in the article. The importance of complex solution to the problem is highlighted: involvement of an administrative resource, realization of the social mechanism of a special type of mutual aid (tutoring), formation in the organization and society of culture of the attitude towards people with peculiarities of health. Everything listed has to be supported by the state measures, including the motivation of teachers to development in a profession and obtaining special professional competences.Practical significance. The research findings can be useful for correction of pedagogical activity during the work with the pupils having features of development and needing special attentionЦель статьи – обсуждение проблем, связанных с современным состоянием инклюзивного образования в России и Болгарии. Методы. Проанализирован и обобщен опыт, позитивные и негативные тенденции в области инклюзивного образования российской и болгарской систем обучения и воспитания. Результаты и научная новизна. Констатируется, что создание условий для получения качественного образования всеми детьми вне зависимости от особенностей их здоровья – социальная гарантия любого постиндустриального государства. Доступ к качественному образованию для детей с особенностями здоровья – целевой ориентир современных реформ российского и болгарского образования в условиях глобализации – присоединения Болгарии к Европейскому Союзу и выхода России как самостоятельного государства на международную образовательную арену. Показано, что неблагоприятные предпосылки развития инклюзивного образования в этих двух странах осложняют разработку и реализацию государственных стратегий по развитию инклюзивного образования. Однако объективные данные о готовности педагогов к внедрению инклюзивного образования и общественная дискуссия вокруг этого вопроса стимулируют лучшее понимание принципов, на которых должна основываться деятельность педагога, направленная на образование детей с ограниченными возможностями здоровья. Сформулированы принципы, позволяющие уточнить профессиональные компетенции педагога в области инклюзивного образования. Подчеркивается важность комплексного решения проблемы – подключения административного ресурса, реализации социального механизма особого вида взаимопомощи (тьюторства), формирования в организации и обществе культуры отношения к людям с особенностями здоровья. Все перечисленное должно поддерживаться государственными мерами, в том числе по мотивации педагогов к развитию в профессии и получению специальных профессиональных компетенций. Практическая значимость. Материалы статьи могут быть полезны при коррекции педагогической деятельности с учащимися, имеющими особенности развития и нуждающимися в особом внимани

Refractive indices of MBE-grown AlxGa(1−x)As ternary alloys in the transparent wavelength region

A series of AlxGa(1−x)As ternary alloys were grown by molecular beam epitaxy (MBE) at the technologically relevant composition range, x < 0.45, and characterized using spectroscopic ellipsometry to provide accurate refractive index values in the wavelength region below the bandgap. Particular attention is given to O-band and C-band telecommunication wavelengths around 1.3 µm and 1.55 µm, as well as at 825 nm. MBE gave a very high accuracy for grown layer thicknesses, and the alloys’ precise compositions and bandgap values were confirmed using high-resolution x-ray diffraction and photoluminescence, to improve the refractive index model fitting accuracy. This work is the first systematic study for MBE-grown AlxGa(1−x)As across a wide spectral range. In addition, we employed a very rigorous measurement-fitting procedure, which we present in detail

One-pot synthesis of a chromeno[4,3,2-de]-1,6-naphthyridine derivative from 4-chlorocoumarin-3-carbaldehyde

In the reaction of 4-chlorocoumarin-3-carbaldehyde with malononitrile in the presence of piperidine a crystalline piperidinium salt of a novel tetracyclic chromeno[4,3,2-de]-1,6-naphthyridine-2-carboxylic acid was isolated instead of the expected product of the &quot;tert-amino effect&quot;. The structure of this piperidinium salt and its corresponding acidic form was characterized through spectral methods (IR, NMR, MS) and elemental analysis. In addition, the structure was established by means of X-ray crystallographic analysis. A theoretical multistep mechanism for this one-pot synthesis is discussed