No abstract available

No abstract available

[en] In this transformation, conjugated base of malonitrile was reacted with reactive nitrilium ion derived from the reaction of isocyanides and oxiranes in the presence of lithium salts in PEG-400. The reaction was successfully utilized to synthesize 3,4-dihydro-2H-pyrans in accordance with a simple and environmentally benign procedure. The optimized reaction conditions allowed the selective synthesis of the highly functionalized 3,4-dihydro-2H-pyrans from the commercially available starting materials in acceptable yields. Graphical abstract: .

[en] Low-energy ion beam served as a novel mutation induction tool treated seeds of red, low-amylose and non-aromatic Sangyod Phatthalung rice (Oryza sativa L. cv. Sangyod Phatthalung) for new mutant rice lines, specifically suited to the rice vermicelli production. Seven thousand dehulled rice seeds were bombarded with 50-kV-accelerated mixed nitrogen ions to a fluence of 4 × 10¹⁶ ions/cm². Seven stable photoperiod-insensitive lines were obtained and studied for their agricultural traits, grain characteristics related to the rice vermicelli production and to confirm their genetic changes. Primarily, these mutants were shorter and produced a higher number of panicles than the wild-type. After 4-month storage, the flour obtained from the mutants exhibited better water absorption index and pasting properties, resulted in an increased rice vermicelli production yield. Genotypic changes in the mutagenized lines were confirmed. The results demonstrated that low-energy N-ion beam irradiation could induce rice mutations to benefit food industry.

[en] Highlights: • Strychnine and brucine exhibited concentration-dependent inhibition of hERG channel. • Strychnine N-oxide and brucine N-oxide lost their activity on hERG channels. • Protonated nitrogen is the key group for strychnine and brucine binding to hERG channel. • Y652 is the most important residue for strychnine and brucine binding to hERG channel. Nux vomica has been effectively used in Traditional Chinese Medicine. The processing of Nux vomica is necessary to reduce toxicity before it can be used in clinical practice. However, the mechanism for processing detoxification is unclear. hERG channels have been subjected to a routine test for compound cardiac toxicity in the drug development process. Therefore, we examined the effects and mechanisms of strychnine and brucine, two main ingredients of Nux vomica, and their N-oxides on hERG channels. Strychnine and brucine exhibited concentration-dependent inhibition of hERG channels with IC₅₀ values of 25.9 μM and 44.18 μM, respectively. However, their nitrogen oxidative derivatives produced by processing of Nux vomica, strychnine N-oxide and brucine N-oxide, lost their activity on hERG channels. Compared to their parent compounds, only an oxygen atom was introduced in the nitrogen oxidative isoforms to compensate for the N⁺ − charge, suggesting that the protonated nitrogen is the key group for strychnine and brucine binding to hERG channel. Alanine-mutagenesis identified Y652 is the most important residue for strychnine and brucine binding to hERG channel. Y652A mutation increased the IC₅₀ for strychnine and brucine by 21.64-fold and 29.78-fold that of WT I_hERG, respectively. Docking simulations suggested that the protonated nitrogen of strychnine and brucine formed a cation–π interaction with the aromatic ring of Y652. This study suggests that introduction of an oxygen to compensate for the N⁺ − charge could be a useful strategy for reducing hERG potency and increasing the safety margin of alkaloid-type compounds in drug development.

[en] The spatial relationship between the concentration and deposition of the major ions in precipitation and stemflow and their influence on the tissue nitrogen concentration of three epiphytic bryophytes on Quercus petraea (Matt) Liebl. and Q. robur L. was investigated at seven UK Atlantic oak woodland sites with a range of total N deposition of 55-250 mmol m^-2. The main driver of change in tissue N concentrations of three epiphytic bryophytes (Isothecium myosuroides Brid. (Eurhynchium myosuroides (Brid.) Schp.), Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp.) was total N deposition in stemflow, dominated by ammonium deposition. The three epiphytic species also showed strong relationships between tissue N concentration and total N deposition in rainfall but a poor correlation with total N ion concentration in rainfall. This study shows that epiphytic bryophytes utilise stemflow N and thus increase their risk from inputs of total N deposition compared to terricolous species at the same site. - Stemflow increases the tissue N concentration of epiphytic bryophytes

[en] A dual-ion-beam technique for the deposition of TiN thin films is described. The metal-atom flux is supplied by sputtering a titanium target with an inert ion beam, while the reactive flux is supplied directly to the growing film by a low-energy ion beam. Results are presented for titanium films deposited at room temperature under a range of N⁺₂ ion bombardment to form TiN. Analysis gives the incorporation of nitrogen, the background gas contamination, and the optical and electrical properties of TiN films

[en] Delayed cavity-free forward lasing at the wavelengths of 391 and 428 nm was observed in recent experiments in air or pure nitrogen pumped with an intense femtosecond laser pulse at wavelength of 800 nm. The mechanism responsible for the lasing is highly controversial. In this article we propose a model explaining the delayed lasing, which contains two parts: (i) ionization of neutral nitrogen molecules and subsequent excitation of nitrogen ions in a strong pump laser pulse, and (ii) coherent emission of excited ions due to the presence of long-lived polarizations maintained by a weak laser post-pulse and coupling simultaneously ground state ${\mathrm{X}}^2{\mathrm{\Sigma <!--\; ??\; -->}}_{\mathrm{g}}^{+}$ to states A²Π_u and ${\mathrm{B}}^2{\mathrm{\Sigma <!--\; ??\; -->}}_u^{+}$ of singly ionized nitrogen molecules ${\mathrm{N}}_2^{+}$. Two regimes of signal amplification are identified: a signal of a few picosecond duration at low gas pressures and a short (sub-picosecond) signal at high gas pressures. The theoretical model compares favorably with results obtained by different experimental groups. (paper)

[en] 1 x 10¹⁷/cm² of N⁺ and N₂⁺ was implanted to two kinds of electric contacts, then a make and break test was made with the low voltage electric apparatus. Parameters such as weight loss of contacts, temperature rise, contact resistance and transfer of material between two contacts were measured and some valuable results have been got. With the contacts implanted by ions, all of the parameters were decreased as compared with those unimplanted afer the make and break. It has been shown that it is very promising to improve the performance of electric contacts by ion implantation

[en] We consider a polymer of length N translocating through a narrow pore in the absence of external fields. The characterization of its purportedly anomalous dynamics has so far remained incomplete. We show that the polymer dynamics is anomalous up to the Rouse time τ_R∼N^1+2ν, with a mean square displacement through the pore consistent with t^{(1+ν)/(1+2ν)}, with ν∼0.588 the Flory exponent. This is shown to be directly related to a decay over time of the excess monomer density near the pore as t^{-(1+ν)/(1+2ν)}exp(-t/τ_R). Beyond the Rouse time, translocation becomes diffusive. In consequence of this, the dwell time τ_d, the time a translocating polymer typically spends within the pore, scales as N^2+ν, in contrast to previous claims. (fast track communication)