Electronic Activation of a DNA Nanodevice Using a Multilayer Nanofilm

A method to control activation of a DNA nanodevice by supplying a complementary DNA (cDNA) strand from an electro‐responsive nanoplatform is reported. To develop functional nanoplatform, hexalayer nanofilm is precisely designed by layer‐by‐layer assembly technique based on electrostatic interaction with four kinds of materials: Hydrolyzed poly(β‐amino ester) can help cDNA release from the film. A cDNA is used as a key building block to activate DNA nanodevice. Reduced graphene oxides (rGOs) and the conductive polymer provide conductivity. In particular, rGOs efficiently incorporate a cDNA in the film via several interactions and act as a barrier. Depending on the types of applied electronic stimuli (reductive and oxidative potentials), a cDNA released from the electrode can quantitatively control the activation of DNA nanodevice. From this report, a new system is successfully demonstrated to precisely control DNA release on demand. By applying more advanced form of DNA‐based nanodevices into multilayer system, the electro‐responsive nanoplatform will expand the availability of DNA nanotechnology allowing its improved application in areas such as diagnosis, biosensing, bioimaging, and drug delivery.     

Compatibilized polypropylene nanocomposites containing expanded graphite and graphene nanoplatelets

We present a non-covalent compatibilization approach to prepare polypropylene (PP) composites containing expanded graphite (EG) and graphene nanoplatelets (GNPs) by melt compounding. This method involves PP matrix functionalization with pyridine (Py) moieties, which are capable of engaging in π-π interactions with the surface of the EG and GNPs. The addition of 10 wt% of PP grafted with amino-pyridine (PP-g-Py) to neat PP facilitated the break-up of EG particles, by intercalating between their layers and facilitating their separation into smaller tactoids. GNPs were prepared starting from EG through a thermomechanical exfoliation method. Addition of GNPs to PP resulted in well-dispersed platelets having aspect ratios as high as 40, whereas in the presence of the PP-g-Py compatibilizer the matrix contained sub-micron scale platelets. The electrical percolation thresholds were in the vicinity of 6 and 10 vol% in the compatibilized PP-EG and PP-GNP composites, respectively, and the maximum value of the electrical conductivity achieved was 10⁻¹ S/m for the compatibilized GNP composites. Addition of GNPs resulted in increases in the flexural moduli by as much as 95% compared to the unfilled PP, whereas the impact strength remained unaffected up to 10 wt% GNP content.     

Antifungal Activity and DNA Topoisomerase Inhibition of Hydrolysable Tannins from Punica granatum L.

Punica granatum L. (pomegranate) fruit is known to be an important source of bioactive phenolic compounds belonging to hydrolysable tannins. Pomegranate extracts have shown antifungal activity, but the compounds responsible for this activity and their mechanism/s of action have not been completely elucidated up to now. The aim of the present study was the investigation of the inhibition ability of a selection of pomegranate phenolic compounds (i.e., punicalagin, punicalin, ellagic acid, gallic acid) on both plant and human fungal pathogens. In addition, the biological target of punicalagin was identified here for the first time. The antifungal activity of pomegranate phenolics was evaluated by means of Agar Disk Diffusion Assay and minimum inhibitory concentration (MIC) evaluation. A chemoinformatic analysis predicted for the first time topoisomerases I and II as potential biological targets of punicalagin, and this prediction was confirmed by in vitro inhibition assays. Concerning phytopathogens, all the tested compounds were effective, often similarly to the fungicide imazalil at the label dose. Particularly, punicalagin showed the lowest MIC for Alternaria alternata and Botrytis cinerea, whereas punicalin was the most active compound in terms of growth control extent. As for human pathogens, punicalagin was the most active compound among the tested ones against Candida albicans reference strains, as well as against the clinically isolates. UHPLC coupled with HRMS indicated that C. albicans, similarly to the phytopathogen Coniella granati, is able to hydrolyze both punicalagin and punicalin as a response to the fungal attack. Punicalagin showed a strong inhibitory activity, with IC₅₀ values of 9.0 and 4.6 µM against C. albicans topoisomerases I and II, respectively. Altogether, the results provide evidence that punicalagin is a valuable candidate to be further exploited as an antifungal agent in particular against human fungal infections.     

Patent information from the Polish Patent Office

The Polish Patent Office activity within the scope of its patent information policy—with emphasis on the changes since the 1990s—is described. In addition to aspects of patent searching, such as documentation and databases, dissemination activities, for example education and training, and the role of Patent Information Centres, is covered. New challenges associated with the promotion of intellectual property protection and its role for the economy are also highlighted.     

Detection of toluene dissolved in water by using PCS fibers excited by an inclined collimated beam

This paper reports results on the sensitivity of straight polymer-clad silica (PCS) detection fibers with short sensing parts coated with polysiloxane polymers to toluene dissolved in water. The detection was based on refractive index changes of the polymers induced by the penetration of toluene into them. These changes were detected by measuring changes of the output power from the detection fibers excited by an inclined collimated beam at 630 nm.

Commercially available Cablelite 950-701 and two types of polymethylphenylsiloxane polymers developed at the Romanian Academy were tested as materials for the fabrication of the detection part in the fiber cladding. These parts were prepared by application of polymer layers onto a bare silica core by a dip-coating technique. Layers with thicknesses of about 20 μm were prepared.

Examples of angular distributions of the output power determined for the detection polymers in contact with air, time response curves measured with the detection parts brought into contact with aqueous solutions of toluene under different hydrodynamic conditions, and sensitivity curves are shown in the paper. The best detection limit of about 10 mg/l of toluene, reversibility and linearity of the fiber response in a range 0–100 mg/l could be achieved with fibers coated with Cablelite 950-701 polymer.     

A Sound Framework for δ-Rule Variants in Free-Variable Semantic Tableaux

We propose a generic sound δ-rule, based on a quite general method for the construction of Skolem terms, which can be used as a common framework for proving the soundness of known variants of the δ-rule, and we compare their relative effectiveness. Attempts to instantiate some of the δ-rules present in the literature within our framework allowed us to pinpoint unsoundness problems for two of them. In both cases, we propose revised versions that are proved sound by reducing them within our framework. This paper is based on results preliminarily presented in [5].     

Diffusion boundaries behaviour during a parabolic flight

The behaviour of a diffusion boundary between distilled water and a 1% sodium chloride solution during a parabolic flight has been observed. The presence of a few percent of Earth gravity pulses during the micro gravity conditions is sufficient to largely perturb the diffusion boundary that stabilises again during the subsequent normal gravity conditions present inside the aircraft at the end of each parabola. A numerical simulation of the boundary behaviour agrees with the experimental observation. Student flying team     

Moment analysis of mass-transfer kinetics in C18-silica monolithic columns

The moment analysis of elution peak profiles based on new moment equations provides information on the mass-transfer characteristics of C(18)-silica monolithic columns. The flow rate dependence of the HETP data was analyzed using the generalized van Deemter equation, after correction of these data by subtraction of the external mass-transfer contribution to band broadening. Kinetic parameters and diffusion coefficients related to the mass-transfer processes in monolithic columns were derived by taking advantage of the different flow velocity dependence of their contributions to band broadening. At high flow rates, axial dispersion and diffusive migration across the monolithic C(18)-silica skeleton contribute much to band broadening, suggesting that it remains important to reduce the influence of eddy diffusion and the mass-transfer resistance in the stationary phase to achieve fast separations and a high efficiency. Surface diffusion plays a predominant role for molecular migration in the monolithic stationary phase. Although the value of the surface diffusion coefficient (D(s)) depends on an estimate of the external mass-transfer coefficient, D(s) values of the order of 10(-7) cm(2) s(-1) were calculated for the first time for the C(18)-silica monolithic skeleton. The value of D(s) decreases with increasing retention of sample compounds. Analysis of a kind of time constant calculated from D(s) suggests that the "chromatographic corresponding particle size" is approximately 4 microm for the C(18)-silica monolithic stationary phase used in this study. The accuracy of the D(s) values determined was discussed.     

Retrospective evaluation of lead contamination in honey from 2005 to present in northeastern Italy and future perspectives in the light of updated legislation

Lead is a naturally occurring element but largely originating from human activities. Food is the major source of exposure to lead for humans and the publication of a scientific opinion from the European Food Safety Authority on the risks to human health related to the presence of lead in foodstuffs, led European Union to establish more restrictive limits for this contaminant in food from 1 January 2016. In particular, a maximum level of 0.10 mg kg^?1 was established for honey. The retrospective evaluation of 995 honey samples analysed since 2005, revealed a progressive reduction in the concentration of lead, with a mean value of 0.045 mg kg^?1 in 2015. Total 1.5% of honeys analysed in 2015 exceeded the maximum lead level and therefore will no longer be marketable. Interested beekeepers should clarify the causes of honey contamination and adopt corrective actions to keep their honey production within the legal levels of lead.