Research on Controlling Contact Electrification by Modification of Cellulose Molecule Surface with Amino Group

As a green material, cellulose is widely used in friction triboelectric nanogenerators (TENGs). However, the weak polarity of the cellulose surface leads to its weak contact electrification performance, which is not conducive to its utilization in TENGs. In this study, epoxy chloropropane and ethylenediamine were grafted onto cellulose to form paper and were assembled with an FEP film. The output voltage, current, and surface charge density were 34.9%, 26.7%, and 16.7% higher than those of ordinary paper, respectively. When 20% nano TiO2 filler was added to the paper made from amino-modified cellulose, the output voltage, current, and surface charge density of the TENG increased by 70.9%, 226.7%, and 122.2%, respectively, compared with ordinary paper. As the air humidity of the TENG increased from 60% to 90%, the output voltage, current, and surface charge density were maintained at 53.7%, 38.9%, and 61.0%, respectively. When a 5 × 107 Ω resistor was connected to the working circuit, its output power reached 13.78 μ W·cm2. This showed that cellulose as a green material has wide application prospects in the field of TENG.

Contact interactions II; Gross-Pitaewskii equation, Bose-Einstein condensate, Fermi sea

In Dell’Antonio (Eur Phys J Plus 13:1–20, 2021), we explored the possibility to analyse contact interaction in Quantum Mechanics using a variational tool, Gamma Convergence. Here, we extend the analysis in Dell’Antonio (Eur Phys J Plus 13:1–20, 2021) of joint weak contact of three particles to the non-relativistic case in which the free one particle Hamiltonian is $$ H_0 = - \frac{\Delta }{2M} $$ H 0 = - Δ 2 M . We derive the Gross–Pitaevskii equation for a system of three particles in joint weak contact. We then define and study strong contact and show that the Gross–Pitaevskii equation is also the variational equation for the energy of the Bose–Einstein condensate (strong contact in a four-particle system). We add some comments on Bogoliubov’s theory. In the second part, we use the non-relativistic Pauli equation and weak contact to derive the spectrum of the conduction electrons in an infinite crystal. We prove that the spectrum is pure point with multiplicity two and eigenvalues that scale as $$ \frac{1}{log {n}}$$ 1 logn .

Entomotoxic Activity of the Extracts from the Fungus, Alternaria tenuissima and Its Major Metabolite, Tenuazonic Acid

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with an LT50 of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of G. mellonella larvae and caused mortality of Acheta domesticus adults (LT50 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing 15% and 27% mortality at a concentration of 1 mg/mL, respectively. TeA was cytotoxic to the Sf9 cell line (IC50 25 µg/mL). Thus, model insects such as G. mellonella could be used for further toxicological characterization of TeA.

Entomotoxic Activity of the Extracts from the Fungus, Alternaria tenuissima and Its Major Metabolite, Tenuazonic Acid

Study of fungal antibiotics in their competitive interactions with arthropods may lead to development novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained by various methods showed a wide range of biological activity, including entomotoxic properties. Analysis of their composition and bioactivity allowed to reveal several known mycotoxins and unidentified compounds that may be involved in entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with LT50 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited growth of G. mellonella larvae and caused mortality of Acheta domesticus imagines (LT50 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact-intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing the 12 and 40% of mortality at a concentration of 1 mg/mL. TeA was cytotoxic to Sf9 cell line (IC50 25 µg/mL). Thus, model insect G. mellonella and cell line Sf9 could be used for a further toxicological characterization of TeA.

Hydroxyapofylit-(K) z kamenolomu Těchlovice u Děčína (Česká republika)

One xenolith of a contactly metamorphosed feldspar-hydroxyapophyllite hornfels from basaltic volcanite of the active quarry in Těchlovice village near-by the town of Děčín has been investigated. Its main components are represented by K-feldspar and hydroxyapophyllite-(K), which was hitherto reported from a single locality only in the territory of the Czech Republic. It forms grains up to 2 mm in size tightly associated with K-feldspar and subsidiary quartz, pyroxene (aegirine, enstatite-ferrosilite and diopside) and titanite. The unit cell parameters of hydroxyapophyllite-(K), derived from the powder X-ray data, are a = 8.975(4), c = 15.8371(3) Å and V = 1275.6(5) Å3. Chemical analyses correspond to the empirical formula K0.93Ca3.75Si7.87O20(OH0.96F0.04)·8 H2O. The xenolith originated by a comparatively weak contact metamorphic effect of the basaltic magma to a marly sediment under high partial pressure of H2O. Among xenoliths of North Bohemian Cainozoic volcanites the rock represents a rarity, which has not been known hitherto.

Insecticidal activity of the extracts of Piper retrofractum fruit and Tephrosia vogelii leaf and their mixtures against Crocidolomia pavonana

This laboratory work was carried out to evaluate the insecticidal activity of the extracts of Piper retrofractum (Piperaceae) fruit and Tephrosia vogelii (Fabaceae) leaf and their mixtures against the cabbage head caterpillar, Crocidolomia pavonana. Ground plant materials of the two plant species were extracted separately with n-hexane and methanol. The results of leaf-residue feeding bioassays showed that P. retrofractum (Pr) and T. vogelii (Tv) hexane extracts had strong insecticidal activity against C. pavonana larvae (LC95 < 0.5%) and were more active than their respective methanol extracts. Pr and Tv hexane extract had a moderate and a rather weak contact effect on C. pavonana larvae, respectively. In feeding tests, Pr + Tv (1:1) hexane and methanol extract mixtures indicated synergistic joint effect both at LC50 and LC95 level, whereas in the contact test, the mixture of Pr + Tv (1:1) hexane extract was synergistic at the LC50 level but antagonistic at the LC95 level. In choice tests, antifeedant effects of Pr and Tv hexane extracts at LC25 to LC70 levels on C. pavonana larvae followed a concentration-dependent fashion. Thus, separate or mixed P. retrofractum and T. vogelii extracts are potential alternatives for the control of C. pavonana.

Planarity in Higher-Dimensional Contact Manifolds

We obtain several results for (iterated) planar contact manifolds in higher dimensions. (1) Iterated planar contact manifolds are not weakly symplectically co-fillable. This generalizes a 3D result of Etnyre [ 14] to a higher-dimensional setting, where the notion of weak fillability is that due to Massot-Niederkrüger-Wendl [ 38]. (2) They do not arise as nonseparating weak contact-type hypersurfaces in closed symplectic manifolds. This generalizes a result by Albers-Bramham-Wendl [ 4]. (3) They satisfy the Weinstein conjecture, that is, every contact form admits a closed Reeb orbit. This is proved by an alternative approach as that of [ 2] and is a higher-dimensional generalization of a result of Abbas-Cieliebak-Hofer [ 1]. The results follow as applications from a suitable symplectic handle attachment, which bears some independent interest.

Mass Transfer and Intrinsic Light Variability in the Contact Binary MT Cas

First CCD photometry for the contact binary MT Cas is performed in 2013 in December. The spectral type of F8V is determined from the low-precision spectrum observed on 2018 Oct 22. With Wilson-Devinney code, the photometric solutions are deduced from VRc light curves (LCs) and AAVSO’s and ASAS-SN’s data, respectively. The results imply that MT Cas is a W-type weak-contact binary with a mass ratio of q=2.365(±0.005) and a fill-out factor of f=16.6(±1.2)%, respectively. The asymmetric LCs in 2013 are modeled by a dark spot on the more massive component. By analyzing the (O-C) curve, it is discovered that the orbital period may be undergoing a secular increase at a rate of dP/dt=1.12(±0.09)×10-8d yr-1, which may result from mass transfer from the less massive component to the more massive one. With mass transferring, MT Cas may evolve into a broken-contact configuration as predicted by TRO theory.

Hydration and ion association of aqueous choline chloride and chlorocholine chloride

Choline hydration occurs predominantly via its hydroxyl group, and weak contact ion pair formation with Cl− is via the onium moiety.