RESUMO
The western conifer seed bug (Leptoglossus occidentalis Heidemann, 1910, Heteroptera: Coreidae) has a significant economic impact due to the reduction in the quality and viability of conifer seed crops; it can feed on up to 40 different species of conifers, showing a clear predilection for Pinus pinea L. in Europe. Its incidence is especially relevant for the pine nut-producing industry, given that the action of this pest insect can reduce the production of pine nuts by up to 25%. As part of ongoing efforts aimed at the design of control strategies for this insect, this work focuses on the characterization (by scanning electron microscopy-energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectroscopy, GC-MS) of the compounds released by these insects during oviposition, with emphasis on the adhesive secretion that holds L. occidentalis eggs together. Elemental analysis pointed to the presence of significant amounts of compounds with high nitrogen content. Functional groups identified by infrared spectroscopy were compatible with the presence of chitin, scleroproteins, LNSP-like and gelatin proteins, shellac wax analogs, and policosanol. Regarding the chemical species identified by GC-MS, eggs and glue hydromethanolic extracts shared constituents such as butyl citrate, dibutyl itaconate, tributyl aconitate, oleic acid, oleamide, erucamide, and palmitic acid, while eggs also showed stearic and linoleic acid-related compounds. Knowledge of this composition may allow advances in new strategies to address the problem caused by L. occidentalis.
RESUMO
The contact between a spherical nanoparticle and a planar substrate is surrounded by an annular wedge cavity. In adsorption processes, this acts like a small pore. Interfacial/capillarity effects lead to an accumulation of adsorbate in this region ("capillary condensation"). This effectively increases the contact area between the particles and the substrate. Thus, capillary-enhanced adsorbate accumulation increases the adhesion between the nanoparticles and the planar surface, which effectively immobilizes the particles.
RESUMO
Oriented arrangement of single crystals plays a key role in improving the performance of their functional devices. Herein we describe a method for the exceptionally fast fabrication (mm/min) of ultralong aligned dipeptide single crystals (several centimeters). It combines an induced nucleation step with a continuous withdrawal of substrate, leading to specific evaporation/composition conditions at a three-phase contact line, which makes the growth process controllable. These aligned dipeptide fibers possess a uniform cross section with active optical waveguiding properties that can be used as waveguiding materials. The approach provides guidance for the controlled arrangement of organic single crystals, a family of materials with considerable potential applications in large-scale functional devices.
