Escape from an optoelectronic tweezer trap: experimental results and simulations

Optoelectronic tweezers (OET) are a microsystem actuation technology capable of moving microparticles at mm s−1 velocities with nN forces. In this work, we analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap. A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured. Three-dimensional simulations were carried out to clarify the experimental results, and the DEP forces acting on the particles were simulated by integrating the Maxwell stress tensor. The simulations matched the experimental results and enabled the determination of a new “hopping” mechanism for particle-escape from the trap. As indicated by the simulations, there exists a vertical DEP force at the edge of the light pattern that pushes up particles to a region with a smaller horizontal DEP force. We propose that this phenomenon will be important to consider for the design of OET micromanipulation experiments for a wide range of applications

Structure and Crystallographic Texture Changes of Ferritic Martensitic Steel Resulting from Thermal Creep and Ageing Tests

Thermal ageing (650 and 700∘C during 1000, 7000 or 13300 h) and creep (700∘C, 50 MPa) tests of tubes made from ferritic-martensitic steels EK181 and ChS139 were carried out. With the aid of X-ray techniques the investigation of crystallographic texture and structure condition after tests was conducted. Thermal ageing provides substructure enhancement. With the increase of ageing time one can note the decrease of microhardness and X-ray peaks broadening, which indicates inner elastic microstress relaxation. It was revealed that changes of crystallographic texture in the rupture area of steel ChS139 tube after creep test is similar to those after uniaxial tensile test at room temeprature. This indicates the similarity of the mechanisms ofgrain reorientation for creep and tension. Recrystallization occurs in steel EK181 during creep test at temperature 700∘C leading to formation of recrystallization texture. This results in faster failure of steel EK181 (2486 h before rupture) in comparison with steel ChS139 (3426 h)

Structure-Sensitive Mechanism of Nanographene Failure

The response of a nanographene sheet to external stresses is considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach is based on a coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to the benzene molecule and (5, 5) nanographene. A drastic anisotropy in the microscopic behavior of both objects under elongation along a MIC has been observed when the MIC is oriented either along or normally to the C-C bonds chain. Both the anisotropy and high stiffness of the nanographene originate at the response of the benzenoid unit to stress.Comment: 19 pages, 7 figures 1 tabl

Этиологическая структура лептоспир, циркулирующих в популяциях сельскохозяйственных животных в Якутии

It is necessary to know the etiological structure of diseases in each region of the country that affects a particular animal species for successful prevention and diagnosis of natural focal diseases, in particular leptospirosis. In this paper, the authors presented research materials on the distribution and etiological structure of pathogenic leptospirosis circulating in the populations of farm animals in Yakutia. Currently, 8 unfavorable points for animal leptospirosis have been registered in Yakutia: two cattle and six horses. A comparative analysis of the etiological structure of leptospirosis in agricultural animals (cattle, horses) testifies to the diversity of leptospira serological groups circulating in the republic. Thus 7 serogroups are registered in cattle, among which the leptospira serogroups Icterohaemorrahagiae (36.0%) and Grippotyphosa (27.1%) dominate. Infection of animals averages 3.2%, in the central zone, where about 63% of the total livestock in the region is concentrated, the level of infection of livestock in the districts of the zone ranges from 0.14 to 8.58%. The highest infection rate of animals is observed in Gorny (8.58%), Namsky (2.26%), and Yakutsk (1.35%) regions. In this zone, circulation of 6 leptospira serogroups is recorded: Grippotyphosa (30.8%), Icterohaemorrahagiae (29.0%) and Tarassovi (27.1%), to a lesser extent Canicola (7.5%), Pomona (3.7%) and Sejroe (1.9%). It should be noted that no Leptospira Hebdomadis were found in cattle in the Central Zone. In Yakut horses, 6 serogroups were identified, among which the leptospira serogroups Hebdomadis (31.5%) and Tarassovi (28.7%) dominate. In the Central zone, where the main number of horses in the region (61.1%) is concentrated the infection rate of animals is an average of 3.2%. The level of infection of horses in the districts of the zone ranges from 0.15 to 8.62%. The highest infection rate of horses is recorded in the horse breeding farms of Gorny (8.62%), Kobyaisky (8.59%), Tattinsky (6.17%), and Churapchinsky (5.74%) districts. It should be noted that L. Pomona does not occur in horses.Для успешной профилактики и диагностики природно-очаговых заболеваний, в частности лептоспироза, необходимо знание этиологической структуры заболевания в каждом регионе страны, поражающего тот или иной вид животных. В данной работе представлены материалы исследований по особенностям распространения и этиологической структуре патогенных лептоспир, циркулирующих в популяциях сельскохозяйственных животных Якутии. В настоящее время на территории Якутии зарегистрировано всего 8 неблагополучных пунктов по лептоспирозу животных: крупного рогатого скота – 2, лошадей – 6. Проведенный сравнительный анализ этиологической структуры лептоспироза сельскохозяйственных животных (крупный рогатый скот, лошади) свидетельствует о разнообразии циркулирующих на территории республики серологических групп лептоспир. Так, у крупного рогатого скота регистрируются 7 серогрупп, среди которых доминируют серогруппы лептоспир Icterohaemorrahagiae (36,0%) и Grippotyphosa (27,1%). В Центральной зоне, где сосредоточено около 63% всего поголовья в регионе, инфицированность животных составляет в среднем 3,2%. Уровень инфицированности скота по районам зоны колеблется от 0,14 до 8,58%. Наиболее высокая инфицированность животных отмечается в Горном (8,58%), Намском (2,26%) и Якутском (1,35%) районах. В этой зоне регистрируется циркуляция 6 серогрупп лептоспир: Grippotyphosa (30,8%), Icterohaemorrahagiae (29,0%) и Tarassovi (27,1%), в меньшей степени Canicola (7,5%), Pomona (3,7%) и Sejroe (1,9%). Следует отметить, что в Центральной зоне у крупного рогатого скота не обнаружены лептоспиры Hebdomadis. У якутских лошадей выявлено 6 серогрупп, среди которых доминируют серогруппы лептоспир Hebdomadis (31,5%) и Tarassovi (28,7%). В Центральной зоне, где сосредоточено основное поголовье лошадей в регионе (61,1%), инфицированность животных составляет в среднем 3,2%. Уровень инфицированности лошадей по районам зоны колеблется от 0,15 до 8,62%. Наиболее высокая инфицированность лошадей регистрируется в коневодческих хозяйствах Горного (8,62%), Кобяйского (8,59%), Таттинского (6,17%) и Чурапчинского (5,74%) районов. Следует отметить, что у лошадей не встречается L. pomona

Taxonomic and ecophysiological characteristics of actinobacteria in soils of the dry steppe zone of the Selenga Highlands (Western Transbaikalia)

Arid habitats have recently attracted increasing attention in terms of biodiversity research and the disco very of new bacterial species. These habitats are among the target ecosystems suitable for isolating new strains of actinobacteria that are likely to produce new metabolites. This paper presents the results on the isolation of actinobacteria from soils of the dry steppe zone of the Selenga Highlands, the characterization of their taxonomic diversity, as well as ecological and trophic properties. The bacterial counts on ISP 4 medium ranged from 6.6 × 105 to 7.1 × 106 CFU/g. The highest bacterial counts were observed in the subsurface and middle horizons of the studied soils. 28 strains of Gram-positive bacteria represented by thin-branched mycelium, coccoid and bacilliform forms were isolated. According to the results of 16S rRNA gene analysis, the isolated strains were representatives of Streptomyces, Arthrobacter, Glycomyces, Kocuria, Microbacterium, Micromonospora, Nocardioides, Pseudarthrobacter, and Rhodococcus (Actinomycetota). One isolate that showed low 16S rRNA gene sequence similarity with previously isolated and validly described species was a new species of the genus Glycomyces. It was shown that all tested strains are mesophilic, prefer neutral or slightly alkaline conditions, have growth limits in the temperature range of 5–45 °C and pH 6–9. The optimal NaCl concentration for growth of most strains was 0–1 %. The strains under study were capable of utilizing a wide range of mono- and disaccharides and polyatomic alcohols as a carbon source. The isolated strains were capable of using both organic (proteins and amino acids) and inorganic (ammonium salts and nitrates) compounds as nitrogen sources. The examinations of extracellular enzymes showed that all isolates were capable of producing catalase and amylase; 78.6 % of the total number of isolates produced protease and lipase; 53.6 %, cellulase; and 28.6 %, urease. The data obtained expand current knowledge about the diversity of microbial communities in soils of the Selenga Highlands and also confirm the potential of searching for new actinobacteria species in these soils

Monoterpenoids dithiophosphates. Synthesis and biological activity

O,O-Dialkyldithiophosphoric acids adds at the double bond of the racemic camphene and (+)- limonene in the presence of Lewis acids in accordance with the Markownikoff rule with the formation of Sterpenyl esters of dithiophosphoric acids. The reaction with camphene is accompanied by the rearrangement of camphane structure to that of bornane. Addition of dithiophosphoric acid to (+)-limonene proceeds with the participation of the exocyclic double bond. Toxic and genotoxic properties of the monoterpenoid dithiophosphates were studied. © Pleiades Publishing, Ltd., 2010

Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

Photolysis (λ \u3e 543 nm) of 3-thienyldiazomethane (1), matrix isolated in Ar or N2 at 10 K, yields triplet 3-thienylcarbene (13) and α-thial-methylenecyclopropene (9). Carbene 13 was characterized by IR, UV/vis, and EPR spectroscopy. The conformational isomers of 3-thienylcarbene (s-E and s-Z) exhibit an unusually large difference in zero-field splitting parameters in the triplet EPR spectrum (|D/hc| = 0.508 cm–1, |E/hc| = 0.0554 cm–1; |D/hc| = 0.579 cm–1, |E/hc| = 0.0315 cm–1). Natural Bond Orbital (NBO) calculations reveal substantially differing spin densities in the 3-thienyl ring at the positions adjacent to the carbene center, which is one factor contributing to the large difference in D values. NBO calculations also reveal a stabilizing interaction between the sp orbital of the carbene carbon in the s-Z rotamer of 13 and the antibonding σ orbital between sulfur and the neighboring carbon—an interaction that is not observed in the s-E rotamer of 13. In contrast to the EPR spectra, the electronic absorption spectra of the rotamers of triplet 3-thienylcarbene (13) are indistinguishable under our experimental conditions. The carbene exhibits a weak electronic absorption in the visible spectrum (λmax = 467 nm) that is characteristic of triplet arylcarbenes. Although studies of 2-thienyldiazomethane (2), 3-furyldiazomethane (3), or 2-furyldiazomethane (4) provided further insight into the photochemical interconversions among C5H4S or C5H4O isomers, these studies did not lead to the spectroscopic detection of the corresponding triplet carbenes (2-thienylcarbene (11), 3-furylcarbene (23), or 2-furylcarbene (22), respectively)

Морфологічні особливості печінки статевозрілої собаки

The article describes the features of the macroscopic and microscopic structure of the liver of mature clinically healthy dogs for the use of anatomical, histological and morphometric methods of research. According to the results of organometallic and cytometric studies, the absolute and relative body mass, the volume of hepatocytes, their nuclei and the nuclear-cytoplasmic ratio were determined. Thus, the absolute weight of the liver in the mature dogs is variable and to a certain extent depends on the blood flow to the organ and is 427.4 ± 21.92 g, the relative weight – 2.69 ± 0.1%. Liver of mature dogs is a compact body of flattened form with sharp lower and lateral edges, with deep cuts, dark red color. The histoarhitectonics of the liver of dogs are constructed with connective tissue and parenchyma. The stroma of the organ is formed by a capsule, on top of which is serous membrane. In the area of the gates of the liver, the connective tissue of the capsule penetrates into the middle of the organ, branching and dividing it into lobules. Then it is formed by the hepatic plates by the intraosseous sinusoid capillaries. Liver plates are specific endpoint of the secretory unit of the liver. It has been found that in the microscopic structure of the liver of the dogs, the interstitial connective tissue is poorly developed, therefore the boundaries between the liver lobules are not sufficient. The liver plates behind the microscopic structure have a radial direction from the center to the periphery. The direction closer to the periphery of the particles is less noticeable, since hepatocytes are located in two rows, between which the sinusoidal space clearly appears. Hepatocytes had an irregular, multifaceted form. Their nuclei, which were mainly in the center of the cell, had little clarity of contours of carriel and well perceived color. During microscopic examination of the liver, it is swollen that hepatocytes of the central and intermediate zones are better perceived by color than the cytoplasm of the cells of the peripheral zone of the liver. According to the analysis of our cytomorphometric studies, hepatocytes of dogs have different sizes, which vary in wide range: from small to large. Whereas the average volume of hepatocytes in mature dogs is 964.72 ± 56.003 μm³; the average volume of their nuclei is 105.13 ± 2.02 microns. The nuclear-cytoplasmic ratio of hepatocytes in dogs of this group is 0.128 ± 0.122.У статті за використання анатомічних, гістологічних та морфометричних методів досліджень викладено особливості макро- та мікроскопічної будови печінки статевозрілих клінічно здорових собак. За результатами органо – гісто- та цитометричних досліджень з’ясовано абсолютну та відносну масу органу, об’єм гепатоцитів, їх ядер та ядерно-цитоплазматичне відношення. Так, абсолютна маса печінки у статевозрілих собак мінлива і в певній мірі залежить від кровонаповнення органа і становить 427,4 ± 21,92 г, відносна маса – 2,69 ± 0,1%. Печінка статевозрілих собак компактний орган сплющеної форми з гострими нижнім і бічними краями, з глибокими вирізками, темно-червоного кольору. Гістоархітектоніка печінки собак побудована зі сполучнотканинної строми і зі паренхіми. Строма органа сформована капсулою, поверх якої міститься серозна оболонка. У ділянці воріт печінки, сполучна тканина капсули проникає всередину органа, розгалужується і ділить його на часточки. Останні утворені печінковими пластинками внутрішньочасточковими синусоїдними капілярами. Печінкові пластинки являють собою специфічний кінцевий секреторний відділ печінки. З’ясовано, що у мікроскопічній будові печінки собак міжчасточкова сполучна тканина слабко розвинена, тому межі між печінковими часточками маловиражені. Печінкові пластинки за мікроскопічної будови мають радіальний напрямок, від центру до периферії. Ближче до периферії часточок їх напрямок менш помітний, оскільки гепатоцити розташовувались двома рядами, між якими чітко виявляється синусоїдальний простір. Гепатоцити мали неправильну, багатогранну форму. Їх ядра, які містилися в основному у центрі клітини, мали чітко контуровану каріолему і добре сприймали забарвлення. Під час мікроскопічного дослідження печінки відмічено, що гепатоцити центральної і проміжної зон краще сприймали забарвлення, ніж цитоплазма клітин периферичної зони печінкової частки. Згідно з аналізом проведених нами цитоморфометричних досліджень, гепатоцити собак мають різні розміри, які коливаються у широких межах: від малих до великих. При тім, що середній об’єм гепатоцитів у статевозрілих собак становить 964,72 ± 56,003 мкм³; середній об’єм їх ядер – 105,13 ± 2,02 мкм3. Ядерно-цитоплазматичне відношення гепатоцитів у собак цієї групи складає 0,128 ± 0,122

GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP

Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension of fast simulation approaches to more use cases, covering a larger fraction of the simulation budget, is only part of the solution due to intrinsic precision limitations. The remainder corresponds to speeding-up the simulation software by several factors, which is out of reach using simple optimizations on the current code base. In this context, the GeantV R&D project was launched, aiming to redesign the legacy particle transport codes in order to make them benefit from fine-grained parallelism features such as vectorization, but also from increased code and data locality. This paper presents extensively the results and achievements of this R&D, as well as the conclusions and lessons learnt from the beta prototype.Comment: 34 pages, 26 figures, 24 table