Lie Symmetry Analysis for Cosserat Rods

We consider a subsystem of the Special Cosserat Theory of Rods and construct an explicit form of its solution that depends on three arbitrary functions in (s,t) and three arbitrary functions in t. Assuming analyticity of the arbitrary functions in a domain under consideration, we prove that the obtained solution is analytic and general. The Special Cosserat Theory of Rods describes the dynamic equilibrium of 1-dimensional continua, i.e. slender structures like fibers, by means of a system of partial differential equations.Comment: 12 Pages, 1 Figur

Photometric and radar observations of an excited eruption in the Zarnitsa-2 experiment

In a controlled experiment a ground photometer and radar station recorded an increase in night sky luminescence following injection of an electron beam into the atmosphere from a rocket at altitudes 80 to 154 km. A main and supplementary scattering and luminescene regions were observed. The effect is presumed to be due to electron eruption induced by artificial action on the magnetosphere

Self-organization of ultrasound in viscous fluids

We report the theoretical and experimental demonstration of pattern formation in acoustics. The system is an acoustic resonator containing a viscous fluid. When the system is driven by an external periodic force, the ultrasonic field inside the cavity experiences different pattern-forming instabilities leading to the emergence of periodic structures. The system is also shown to possess bistable regimes, in which localized states of the ultrasonic field develop. The thermal nonlinearity in the viscous fluid, together with the far-from-equilibrium conditions, are is the responsible of the observed effects

Conductive inks for inkjet printing based on composition of nanoparticles and organic silver salt

In this article, conductive inks for inkjet printing with high content of silver nanoparticles with the addition of organic silver salt and polymer additives are developed and investigated. Silver nanoparticles are shown to be stably dispersed in a solvent and the presence of a silver salt and a polymeric surfactant ensures the viscosity necessary for printing. A print of test images is performed using a laboratory inkjet printer equipped with an industrial small-droplet printhead followed by annealing of printed patterns at 150–250°C, and their structural and electrical properties are investigated. Simultaneous presence of polymer additives and silver salt is found to influence the structure of the forming conductive layer and the conducting properties

Correlation between binding rate constants and individual information of E. coli Fis binding sites

Individual protein binding sites on DNA can be measured in bits of information. This information is related to the free energy of binding by the second law of thermodynamics, but binding kinetics appear to be inaccessible from sequence information since the relative contributions of the on- and off-rates to the binding constant, and hence the free energy, are unknown. However, the on-rate could be independent of the sequence since a protein is likely to bind once it is near a site. To test this, we used surface plasmon resonance and electromobility shift assays to determine the kinetics for binding of the Fis protein to a range of naturally occurring binding sites. We observed that the logarithm of the off-rate is indeed proportional to the individual information of the binding sites, as predicted. However, the on-rate is also related to the information, but to a lesser degree. We suggest that the on-rate is mostly determined by DNA bending, which in turn is determined by the sequence information. Finally, we observed a break in the binding curve around zero bits of information. The break is expected from information theory because it represents the coding demarcation between specific and nonspecific binding

Discovery of Fur binding site clusters in Escherichia coli by information theory models

Fur is a DNA binding protein that represses bacterial iron uptake systems. Eleven footprinted Escherichia coli Fur binding sites were used to create an initial information theory model of Fur binding, which was then refined by adding 13 experimentally confirmed sites. When the refined model was scanned across all available footprinted sequences, sequence walkers, which are visual depictions of predicted binding sites, frequently appeared in clusters that fit the footprints (∼83% coverage). This indicated that the model can accurately predict Fur binding. Within the clusters, individual walkers were separated from their neighbors by exactly 3 or 6 bases, consistent with models in which Fur dimers bind on different faces of the DNA helix. When the E. coli genome was scanned, we found 363 unique clusters, which includes all known Fur-repressed genes that are involved in iron metabolism. In contrast, only a few of the known Fur-activated genes have predicted Fur binding sites at their promoters. These observations suggest that Fur is either a direct repressor or an indirect activator. The Pseudomonas aeruginosa and Bacillus subtilis Fur models are highly similar to the E. coli Fur model, suggesting that the Fur–DNA recognition mechanism may be conserved for even distantly related bacteria

Understanding the nature of "superhard graphite"

Numerous experiments showed that on cold compression graphite transforms into a new superhard and transparent allotrope. Several structures with different topologies have been proposed for this phase. While experimental data are consistent with these models, the only way to solve this puzzle is to find which structure is kinetically easiest to form. Using state-of-the-art molecular-dynamics transition path sampling simulations, we investigate kinetic pathways of the pressure-induced transformation of graphite to various superhard candidate structures. Unlike hitherto applied methods for elucidating nature of superhard graphite, transition path sampling realistically models nucleation events necessary for physically meaningful transformation kinetics. We demonstrate that nucleation mechanism and kinetics lead to $M$-carbon as the final product. $W$-carbon, initially competitor to $M$-carbon, is ruled out by phase growth. Bct-C$_4$ structure is not expected to be produced by cold compression due to less probable nucleation and higher barrier of formation

Diet and subsistence in Bronze Age pastoral communities from the southern Russian steppes and the North Caucasus

The flanks of the Caucasus Mountains and the steppe landscape to their north offered highly productive grasslands for Bronze Age herders and their flocks of sheep, goat, and cattle. While the archaeological evidence points to a largely pastoral lifestyle, knowledge regarding the general composition of human diets and their variation across landscapes and during the different phases of the Bronze Age is still restricted. Human and animal skeletal remains from the burial mounds that dominate the archaeological landscape and their stable isotope compositions are major sources of dietary information. Here, we present stable carbon and nitrogen isotope data of bone collagen of 105 human and 50 animal individuals from the 5th millennium BC to the Sarmatian period, with a strong focus on the Bronze Age and its cultural units including Maykop, Yamnaya, Novotitorovskaya, North Caucasian, Catacomb, post-Catacomb and late Bronze Age groups. The samples comprise all inhumations with sufficient bone preservation from five burial mound sites and a flat grave cemetery as well as subsamples from three further sites. They represent the Caucasus Mountains in the south, the piedmont zone and Kuban steppe with humid steppe and forest vegetation to its north, and more arid regions in the Caspian steppe. The stable isotope compositions of the bone collagen of humans and animals varied across the study area and reflect regional diversity in environmental conditions and diets. The data agree with meat, milk, and/or dairy products from domesticated herbivores, especially from sheep and goats having contributed substantially to human diets, as it is common for a largely pastoral economy. This observation is also in correspondence with the faunal remains observed in the graves and offerings of animals in the mound shells. In addition, foodstuffs with elevated carbon and nitrogen isotope values, such as meat of unweaned animals, fish, or plants, also contributed to human diets, especially among communities living in the more arid landscapes. The regional distinction of the animal and human data with few outliers points to mobility radii that were largely concentrated within the environmental zones in which the respective sites are located. In general, dietary variation among the cultural entities as well as regarding age, sex and archaeologically indicated social status is only weakly reflected. There is, however, some indication for a dietary shift during the Early Bronze Age Maykop period

Синтез і цитотоксичність аміноетоксидифенілів

The implementation mechanism of the antiviral activity (AA) and interferon induction (IFI) by planar polycyclic compounds has not yet been determined. However, our hypothesis of the priority role of intercalation in double strand nucleic acids (NA) has gained strong arguments in its favour in our works and the works of foreign colleagues.On the other hand, the presence of AA and the ability to induce IFI in biphenyl derivatives that are incapable to intercalate in NA indicates the possibility of implementing alternative mechanisms. This determined our interest to the study of aminoethoxydiphenyls (AED), which synthesis and investigation of cytotoxicity become the subject of this article. 4,4’-Bis-(2-chloroethoxy)diphenyl was obtained by alkylation of dihydroxydiphenyl with dichloroethane in its mixture with aqueous sodium hydroxide (20%) in the presence of tetrabutylammonium chloride (TBAC). Series of AED were synthesized by substitution of chlorine by iodine in the mixture of xylene with the aqueous solution of sodium iodide in the presence of TBAC with subsequent amination with primary and secondary amines. The protonated molecular ions (MI) intensive peaks of the compounds synthesized are observed in the mass spectra with FAB ionization. The most common way of MI fragmentation is PhO-CH2-bond cleavage following the side aminoalkyl fragment detachment. Absorption bands typical for CH (arom.), CH (aliph.), COC bonds and NH protonated terminal amino groups are present in IR spectra. In the 1H-NMR spectra signals from aromatic and aliphatic protons present, multiplicity and integral intensity correspond to the attributed structures. Cytotoxicity of the compounds synthesized was tested using EPT cells in vitro. All AED tested appeared to be comparable to amixine and are in the range from low to moderate cytotoxicity.Механизм реализации противовирусной активности (ПА) и индукции индерферона (ИФН) планарными полициклическими соединениями до сих пор не установлен, хотя выдвинутая нами гипотеза о приоритетной роли интеркаляции в двухспиральные нуклеиновые кислоты (НК) получила весомые аргументы в свою пользу в наших работах и работах зарубежных коллег. С другой стороны, наличие ПА и способности индуцировать ИФН в производных дифенила, не способных к интеркаляции в НК, указывает на возможность реализации альтернативных механизмов. Это и определило наш интерес к развернутому исследованию аминоалкоксидифенила (ААД), началу которого – синтезу и исследованию цитотоксичности ААД и посвящена эта статья. Алкилированием дигидроксибифенила дихлорэтаном в смеси водного раствора гидроксида натрия (20%) с 1,2-дихлорэтаном в присутствии тетрабутиламмония хлорида (ТБАХ) получен 4,4’-бис-(2-хлороэтокси) бифенил. Замену хлора на йод проводили в смеси ксилола с водным раствором йодида натрия в присутствии ТБАЙ с последующим аминированием рядом первичных и вторичных аминов; синтезирован ряд АЭД. В масс-спектрах с ионизацией БУА синтезированных соединений имеются интенсивные пики протонированных молекулярных ионов (МИ), наиболее типичным путем фрагментации МИ является разрыв связи PhO-CH2 с отщеплением бокового аминоалкильного фрагмента. В ИК-спектрах наблюдаются полосы поглощения, характерные для связей CH (аром.), CH (алиф), COC и NH протонованных терминальных аминогрупп. В спектрах 1H-ЯМР имеются сигналы от ароматических и алифатических протонов, мультиплетность и интегральная интенсивность которых соответствуют приписываемым структурам. На клетках ПТП изучена цитотоксичность ряда 4,4’-бис-(2-аминоэтокси)дифенилов, значения сопоставимы с цитотоксичностью амиксина и находятся в диапазоне от низких до умеренных.Механізм реалізації противірусної активності (ПА) та індукції інтерферону (ІФН) планарними поліциклічними сполуками досі не встановлено, хоча висунута нами гіпотеза про пріоритетну роль інтеркаляції в двоспіральні нуклеїнові кислоти (НК) набула вагомих аргументів на свою користь в наших роботах та роботах іноземних колег. З іншого боку, наявність ПА та здатності індукувати ІФН у похідних дифенілу, не здатних до інтеркаляції у НК, вказує на можливість реалізації альтернативних механізмів. Це й спричинило наш інтерес до поглибленого дослідження аміноалкоксидифенілів (АЕД), початку якого – синтезу та дослідженню цитотоксичності АЕД і присвячена ця стаття. Алкілуванням дигідроксибіфенілу дихлороетаном у суміші водного розчину гідроксиду натрію (20%) з 1,2-дихлороетаном у присутності тетрабутиламонію хлориду (ТБАХ) отримано 4,4’-біс-(2-хлороетокси)біфеніл. Заміну хлору на йод проводили в суміші ксилолу з водним розчином йодиду натрію в присутності ТБАЙ з наступним амінуванням низкою первинних та вторинних амінів; синтезована низка АЕД. В мас-спектрах з іонізацією БПА синтезованих сполук наявні інтенсивні піки протонованих молекулярних іонів (МІ), найбільш типовим шляхом фрагментації МІ є розрив зв’язку PhO–CH2 з відщепленням бокового аміноалкільного фрагменту. В ІЧ-спектрах наявні смуги поглинання, характерні для зв’язків C-H (аром.), C-H (аліф), C-O-C та NH протонованих термінальних аміногруп. У спектрах 1H-ЯМР наявні сигнали від ароматичних та аліфатичних протонів, мультиплетність та інтегральна інтенсивність яких відповідає приписуваним структурам. На клітинах ПТП вивчена цитотоксичність низки 4,4’-біс-(2-аміноетокси)дифенілів, значення якої зіставні з токсичністю аміксину та знаходяться в діапазоні від низьких до помірних

Virtual screening, synthesis and biological evaluation of DNA intercalating antiviral agents

© 2017 Elsevier Ltd This paper describes computer-aided design of new anti-viral agents against Vaccinia virus (VACV) potentially acting as nucleic acid intercalators. Earlier obtained experimental data for DNA intercalation affinities and activities against Vesicular stomatitis virus (VSV) have been used to build, respectively, pharmacophore and QSAR models. These models were used for virtual screening of a database of 245 molecules generated around typical scaffolds of known DNA intercalators. This resulted in 12 hits which then were synthesized and tested for antiviral activity against VaV together with 43 compounds earlier studied against VSV. Two compounds displaying high antiviral activity against VaV and low cytotoxicity were selected for further antiviral activity investigations