Optimal control of electromagnetic field using metallic nanoclusters

The dielectric properties of metallic nanoclusters in the presence of an applied electromagnetic field are investigated using non-local linear response theory. In the quantum limit we find a non-trivial dependence of the induced field and charge distribution on the spatial separation between the clusters and on the frequency of the driving field. Using a genetic algorithm, these quantum functionalities are exploited to custom-design sub-wavelength lenses with a frequency controlled switching capability.Comment: accepted for publication in New Journal of Physic

Mechanics and Mathematical Modeling of Class III Treatment with Orthodontic Appliances with a Movable Ramp

Treatment of class III is a current problem in orthodontics that requires constant improvement of its methods, development of new or modifications of known methods and techniques. We have developed and studied the modification of removable functionally-directing orthodontic appliances for treatment of Class III, which consists of a plastic base, vestibular arc, retaining clasps, ramp, which is connected with the base by means of two torsion springs. Its usage ensures a prolonged contact of ramp with the teeth. We studied two types of club-shaped springs (torsion springs): one spring, which create an amortization effect during the action of the ramp, but do not change its inclination angle and second one – spring that seek to increase the angle of the ramp inclination due to the disclosure of its curl

Non-polaritonic effects in cavity-modified photochemistry

Strong coupling of molecules to vacuum fields has been widely reported to lead to modified chemical properties such as reaction rates. However, some recent attempts to reproduce infrared strong coupling results have not been successful, suggesting that factors other than strong coupling may sometimes be involved. Here we re-examine the first of these vacuum-modified chemistry experiments, in which changes to a molecular photoisomerisation process were attributed to strong coupling of the molecules to visible light. We observed significant variations in photoisomerisation rates for molecules placed in a variety of optical cavity structures, but found no evidence that these changes need to be attributed to strong coupling. Instead, we suggest that the photoisomerisation rates involved are most strongly influenced by the absorption of ultraviolet radiation in the cavity. Our results indicate that care must be taken to rule out non-polaritonic effects before invoking strong coupling to explain any changes of chemical properties arising in cavity-based experiments.Comment: 31 pages, 16 figure

STUDY OF ANTI-OSTEOPOROTIC ACTION OF DRUGS FROM THE GROUP OF STATINS

In an experiment on female Wistar white rats, the osteoprotective effect of atorvastatin, simvastatin and rosuvastatin was studied in a model of experimental osteoporosis caused by bilateral ovariectomy. It was found that after ovariectomy in female rats develops endothelial dysfunction, including the vessels of the microcirculatory of the bone, leading to a deterioration of blood supply to bone tissue and the occurrence of osteoporosis. It was found that atorvastatin, simvastatin and rosuvastatin, possessing endothelioprotective activity, prevent deterioration of blood supply to bone tissue and thinning of bone trabeculae, thus having anti-osteoporotic activity. Key words: osteoporosis, endothelial dysfunction, statins, atorvastatin, simvastatin, rosuvastatin, strontium ranelate

IN MEMORY OF ARKADY VIKTOROVICH KRYAZHIMSKIY (1949–2014)

The article is devoted to the description of Academician Arkady Kryazhimskiy's life path. The facts of the scientific biography of Acad. Kryazhimskiy are presented with the emphasis on his outstanding contribution into the theory of dynamic inversion, the theory of differential games, and control theory. His personal talents in different spheres are also marked out

IN MEMORY OF ARKADY VIKTOROVICH KRYAZHIMSKIY (1949–2014)

The article is devoted to the description of Academician Arkady Kryazhimskiy's life path. The facts of the scientific biography of Acad. Kryazhimskiy are presented with the emphasis on his outstanding contribution into the theory of dynamic inversion, the theory of differential games, and control theory. His personal talents in different spheres are also marked out

Mutational re-modeling of di-aspartyl intramembrane proteases: uncoupling physiologically-relevant activities from those associated with Alzheimer\u27s disease

The intramembrane proteolytic activities of presenilins (PSEN1/PS1 and PSEN2/PS2) underlie production of beta-amyloid, the key process in Alzheimer\u27s disease (AD). Dysregulation of presenilin-mediated signaling is linked to cancers. Inhibition of the gamma-cleavage activities of PSENs that produce Abeta, but not the epsilon-like cleavage activity that release physiologically essential transcription activators, is a potential approach for the development of rational therapies for AD. In order to identify whether different activities of PSEN1 can be dissociated, we designed multiple mutations in the evolutionary conserved sites of PSEN1. We tested them in vitro and in vivo assays and compared their activities with mutant isoforms of presenilin-related intramembrane di-aspartyl protease (IMPAS1 (IMP1)/signal peptide peptidase (SPP)). PSEN1 auto-cleavage was more resistant to the mutation remodeling than the epsilon-like proteolysis. PSEN1 with a G382A or a P433A mutation in evolutionary invariant sites retains functionally important APP epsilon- and Notch S3- cleavage activities, but G382A inhibits APP gamma-cleavage and Abeta production and a P433A elevates Abeta. The G382A variant cannot restore the normal cellular ER Ca(2+) leak in PSEN1/PSEN2 double knockout cells, but efficiently rescues the loss-of-function (Egl) phenotype of presenilin in C. elegans. We found that, unlike in PSEN1 knockout cells, endoplasmic reticulum (ER) Ca(2+) leak is not changed in the absence of IMP1/SPP. IMP1/SPP with the analogous mutations retained efficiency in cleavage of transmembrane substrates and rescued the lethality of Ce-imp-2 knockouts. In summary, our data show that mutations near the active catalytic sites of intramembrane di-aspartyl proteases have different consequences on proteolytic and signaling functions

Methane pyrolysis on sponge iron powder for sustainable hydrogen production

Methane pyrolysis is one of the possible methods to produce low-carbon hydrogen. One of the most promising catalysts for methane pyrolysis is Fe due to its availability, relatively low cost and high working temperature. In the presented paper, the methane pyrolysis on unsupported (without a carrier) sponge iron in the form of powder was studied in the temperature range of 700–1100 ◦ C. Methane pyrolysis was carried out in a stainless-steel tube reactor with an inner diameter of 10 mm. The reactor was heated locally by propane burner, the length of the heated zone was about 8 cm along the reactor tube. Methane feed rates were about 50, 100, and 200 ml/min, and the residence time of methane in the 8 cm long reaction zone was about 4, 2 and 1 s, respectively. The hydrogen yield increased with an increase in the temperature and a decrease in methane feed rate. At 700–800 ◦C, the hydrogen yield did not exceed 20%. At 900 ◦C, the yield reached 28.6% at a residence time of about 4 s. At 1000 ◦C, hydrogen yield was about 40 and 66.5% at a residence time of about 1 and 4 s, respectively. At 1100 ◦C, hydrogen yield varied in the range of 70–85%. The use of a catalyst increased the hydrogen yield by 81% compared to the experiment without a catalyst at 1100 ◦C. The catalytic effect of sponge iron powder can be used in the development of methane pyrolysis plants

Rapid automatized naming as an index of genetic liability to autism

This study investigated rapid automatized naming (RAN) ability in high functioning individuals with autism and parents of individuals with autism. Findings revealed parallel patterns of performance in parents and individuals with autism, where both groups had longer naming times than controls. Significant parent-child correlations were also detected, along with associations with language and personality features of the broad autism phenotype (retrospective reports of early language delay, socially reticent personality). Together, findings point towards RAN as a potential marker of genetic liability to autism

Long-range and rapid transport of individual nano-objects by a hybrid electrothermoplasmonic nanotweezer

Plasmon-enhanced optical trapping is being actively studied to provide efficient manipulation of nanometre-sized objects. However, a long-standing issue with previously proposed solutions is how to controllably load the trap on-demand without relying on Brownian diffusion. Here, we show that the photo-induced heating of a nanoantenna in conjunction with an applied a.c. electric field can initiate rapid microscale fluid motion and particle transport with a velocity exceeding 10 μm s -1 , which is over two orders of magnitude faster than previously predicted. Our electrothermoplasmonic device enables on-demand long-range and rapid delivery of single nano-objects to specific plasmonic nanoantennas, where they can be trapped and even locked in place. We also present a physical model that elucidates the role of both heat-induced fluidic motion and plasmonic field enhancement in the plasmon-assisted optical trapping process. Finally, by applying a d.c. field or low-frequency a.c. field (below 10 Hz) while the particle is held in the trap by the gradient force, the trapped nano-objects can be immobilized into plasmonic hotspots, thereby providing the potential for effective low-power nanomanufacturing on-chip