Broadband light bending with plasmonic nanoantennas

The precise manipulation of a propagating wave using phase control is a fundamental building block of optical systems. The wavefront of a light beam propagating across an interface can be modified arbitrarily by introducing abrupt phase changes. We experimentally demonstrated unparalleled wavefront control in a broadband optical wavelength range from 1.0 to 1.9 micrometers. This is accomplished by using an extremely thin plasmonic layer (~λ/50) consisting of an optical nanoantenna array that provides subwavelength phase manipulation on light propagating across the interface. Anomalous light-bending phenomena, including negative angles of refraction and reflection, are observed in the operational wavelength range.     

Improvement of Forage Production Sustainability in the Leningrad Region under Climate Change

The increase of probability and depth of weather anomalies, which is important characteristic of climate change process, leads to higher risk of loss of perennial grasses forage yield, rise of price volatility on forage grain market. Increase of sustainability of dairy production supposes development of adapted to new weather conditions technologies of forage production, which are characterized by different investment and current costs. It generates a need of economic evaluation and comparative analysis of technologies taking into account climate change forecast and need of sustainable forage production guarantee. Purpose of the research project is the development of approaches to assessing adaptive technologies in forage production, increasing of dairy farming sustainability to changes in the external environment, including climate change. We assessed changes in forage production technologies in the Leningrad region of Russia, analyzed the implications of these changes for production and financial performance of dairy farming, proposed and tested methods for determination of the optimum harvesting time of perennial grasses. Special attention is paid to the long-term effects of changing the structure of cows＇ diet--shortening the productive use of animals, which reduces the efficiency of dairy herd use and limits the possibility of expanded reproduction. The primary method of the study is the analysis of milk production statistics in the Leningrad region and the Russian Federation. As a result of the study, the necessity to improve the production and investment planning quality, as well as the use of forecasts during planning of dairy production, is grounded.     

Efficacy and Mechanism of Action of Marine Alkaloid 3,10-Dibromofascaplysin in Drug-Resistant Prostate Cancer Cells

Efficacy and mechanism of action of marine alkaloid 3,10-dibromofascaplysin (DBF) were investigated in human prostate cancer (PCa) cells harboring different levels of drug resistance. Anticancer activity was observed across all cell lines examined without signs of cross-resistance to androgen receptor targeting agents (ARTA) or taxane based chemotherapy. Kinome analysis followed by functional investigation identified JNK1/2 to be one of the molecular targets of DBF in 22Rv1 cells. In contrast, no activation of p38 and ERK1/2 MAPKs was observed. Inhibition of the drug-induced JNK1/2 activation or of the basal p38 activity resulted in increased cytotoxicity of DBF, whereas an active ERK1/2 was identified to be important for anticancer activity of the alkaloid. Synergistic effects of DBF were observed in combination with PARP-inhibitor olaparib most likely due to the induction of ROS production by the marine alkaloid. In addition, DBF intensified effects of platinum-based drugs cisplatin and carboplatin, and taxane derivatives docetaxel and cabazitaxel. Finally, DBF inhibited AR-signaling and resensitized AR-V7-positive 22Rv1 prostate cancer cells to enzalutamide, presumably due to AR-V7 down-regulation. These findings propose DBF to be a promising novel drug candidate for the treatment of human PCa regardless of resistance to standard therapy.     

The use of citrus tristeza virus (CTV) containing a green fluorescent protein gene as a tool to evaluate resistance/tolerance of transgenic citrus plants

The T36 strain of citrus tristeza virus (CTV) expressing green fluorescent protein gene (CTV-GFP) was used to detect replication of CTV in wild-type (WT) ‘Hamlin’ sweet orange plants and those transformed with the use of Agrobacterium tumefaciens strain harboring a binary vector with a coat protein gene from either T36 or T30 isolate of CTV. Soil-adapted WT and transgenic plants were challenged with CTV by grafting shoots from CTV-GFP infected plants. None of the transgenic plants appeared to be able to inhibit CTV replication as CTV-associated GFP fluorescence in all of them was detected by fluorescent microscopy. For the purpose of comparison of two different methods, CTV multiplication in transgenic plants was also examined by enzyme-linked immunosorbent assay (ELISA) assays. GFP-labeled CTV represents a useful tool for estimation of susceptibility of citrus cultivars or transgenic lines to CTV infection. This method using CTV-GFP is simpler, cheaper and less time-consuming than ELISA.     

Study of Structure–Activity Relationships of the Marine Alkaloid Fascaplysin and Its Derivatives as Potent Anticancer Agents

Marine alkaloid fascaplysin and its derivatives are known to exhibit promising anticancer properties in vitro and in vivo. However, toxicity of these molecules to non-cancer cells was identified as a main limitation for their clinical use. Here, for the very first time, we synthesized a library of fascaplysin derivatives covering all possible substituent introduction sites, i.e., cycles A, C and E of the 12H-pyrido[1-2-a:3,4-b’]diindole system. Their selectivity towards human prostate cancer versus non-cancer cells, as well as the effects on cellular metabolism, membrane integrity, cell cycle progression, apoptosis induction and their ability to intercalate into DNA were investigated. A pronounced selectivity for cancer cells was observed for the family of di- and trisubstituted halogen derivatives (modification of cycles A and E), while a modification of cycle C resulted in a stronger activity in therapy-resistant PC-3 cells. Among others, 3,10-dibromofascaplysin exhibited the highest selectivity, presumably due to the cytostatic effects executed via the targeting of cellular metabolism. Moreover, an introduction of radical substituents at C-9, C-10 or C-10 plus C-3 resulted in a notable reduction in DNA intercalating activity and improved selectivity. Taken together, our research contributes to understanding the structure–activity relationships of fascaplysin alkaloids and defines further directions of the structural optimization.     

Antimicrobial ent-pimarane diterpenes from Viguiera arenaria against Gram-positive bacteria

The dichloromethane crude extract from the roots of Viguiera arenaria (VaDRE) has been employed in an antimicrobial screening against several bacteria responsible for human pathologies. The main diterpenes isolated from this extract, as well as two semi-synthetic pimarane derivatives, were also investigated for the pathogens that were significantly inhibited by the extract (MIC values lower than 100 μg mL^− 1). The VaDRE extract was significantly active only against Gram-positive microorganisms. The compounds ent-pimara-8(14),15-dien-19-oic acid (PA); PA sodium salt; ent-8(14),15-pimaradien-3β-ol; ent-15-pimarene-8β,19-diol; and ent-8(14),15-pimaradien-3β-acetoxy displayed the highest antibacterial activities (MIC values lower than 10 μg mL^− 1 for most pathogens). In conclusion, our results suggest that pimaranes are an important class of natural products for further investigations in the search of new antibacterial agents.     

Stock evaluation of giant scallop (Placopecten magellanicus) using high-resolution acoustics for seabed mapping

Survey designs in use for the evaluation of sea scallop stocks do not consider the variability of sediment type, despite strong evidence of its importance for the recruitment and survival of scallops on the sea floor. This study examines the distribution of scallops on Browns Bank, Scotian Shelf, at two test sites, in comparison to sea floor sediment distribution, with particular attention to the effects of small-scale sediment variability on the abundance of the commercially exploited scallop. Important links between scallop abundance, sediment type and habitat structure are described. Scallops are strongly associated with gravel lag deposits, which are readily distinguishable from sand-covered terrain through the use of multibeam backscatter data. There exists a highly significant correlation between scallop survey catch rates and backscatter intensity which can be used for the prediction of scallop stock abundance. Developments in underwater acoustics enable for more precise sea floor mapping and contribute to better estimates of scallop abundance.     

Tomography of reaction-diffusion microemulsions reveals three-dimensional Turing patterns

Spatially periodic, temporally stationary patterns that emerge from instability of a homogeneous steady state were proposed by Alan Turing in 1952 as a mechanism for morphogenesis in living systems and have attracted increasing attention in biology, chemistry, and physics. Patterns found to date have been confined to one or two spatial dimensions. We used tomography to study the Belousov-Zhabotinsky reaction in a microemulsion in which the polar reactants are confined to aqueous nanodroplets much smaller than the scale of the stationary patterns. We demonstrate the existence of Turing patterns that can exist only in three dimensions, including curved surfaces, hexagonally packed cylinders, spots, and labyrinthine and lamellar patterns.     

Extraction and characterization of volatile compounds in Maytenus ilicifolia, using high-pressure CO2

This work is focused on the chemical characterization of Maytenus ilicifolia extracts obtained from high-pressure CO2 extraction. The experiments were performed in a laboratory-scale unit, where the effect of particle size (35-200 mesh), CO2 mass flow rate (1-3 g/min), temperature (293-323 K), pressure (100-250 bar), and extraction time was investigated in terms of liquid yield and chemical composition of the extracts. Results show that the particle size and CO2 mass flow rate did not affect the liquid yield, whereas the extraction temperature and solvent density exerted a pronounced effect on both liquid yield and chemical distribution of volatile compounds. The extracts were chemically analyzed with regard to phytol, squalene, vitamin E, stigmasterol, friedelan-3-ol, friedelin, dodecanoic acid and geranyl acetate in a GC/MSD.