Resonant plasmonic nanoparticles for multicolor second harmonic imaging

Nanoparticles capable of efficiently generating nonlinear optical signals, like second harmonic generation, are attracting a lot of attention as potential background-free and stable nano-probes for biological imaging. However, second harmonic nanoparticles of different species do not produce readily distinguishable optical signals, as the excitation laser mainly defines their second harmonic spectrum. This is in marked contrast to other fluorescent nano-probes like quantum dots that emit light at different colors depending on their sizes and materials. Here, we present the use of resonant plasmonic nanoparticles, combined with broadband phase-controlled laser pulses, as tunable sources of multicolor second harmonic generation. The resonant plasmonic nanoparticles strongly interact with the electromagnetic field of the incident light, enhancing the efficiency of nonlinear optical processes. Because the plasmon resonance in these structures is spectrally narrower than the laser bandwidth, the plasmonic nanoparticles imprint their fingerprints on the second harmonic spectrum. We show how nanoparticles of different sizes produce different colors in the second harmonic spectra even when excited with the same laser pulse. Using these resonant plasmonic nanoparticles as nano-probes is promising for multicolor second harmonic imaging while keeping all the advantages of nonlinear optical microscopy.Peer ReviewedPostprint (published version

A redescription of Planctoteuthis levimana (Lönnberg, 1896) (Mollusca: Cephalopoda), with a brief review of the genus

We re-describe Planctoteuthis levimana (Lönnberg, 1896), a poorly known species of oegopsid squid in the Chiroteuthidae, based on two specimens taken from near the type locality. We also designate a neotype for P. levimana. We demonstrate that P. levimana is a valid taxon through brief comparisons with other members of the genus, and we assess the importance of the funnel locking-apparatus as a species-level character in Planctoteuthis

Polarization control of metal-enhanced fluorescence in hybrid assemblies of photosynthetic complexes and gold nanorods

Fluorescence imaging of hybrid nanostructures composed of a bacterial light-harvesting complex LH2 and Au nanorods with controlled coupling strength is employed to study the spectral dependence of the plasmon-induced fluorescence enhancement. Perfect matching of the plasmon resonances in the nanorods with the absorption bands of the LH2 complexes facilitates a direct comparison of the enhancement factors for longitudinal and transverse plasmon frequencies of the nanorods. We find that the fluorescence enhancement due to excitation of longitudinal resonance can be up to five-fold stronger than for the transverse one. We attribute this result, which is important for designing plasmonic functional systems, to a very different distribution of the enhancement of the electric field due to the excitation of the two characteristic plasmon modes in nanorods

Методика проектирования и технологическая схема повторной ликвидации наклонных стволов закрытых угольных шахт

На основе аналитических и технологических исследований разработаны методика проектирования и технологическая схема повторной ликвидации наклонных выработок закрытых шахт способом тампонажа ресурсосберегающими безусадочными смесями. Технология позволяет обеспечить геомеханическую устойчивость породного массива

Predation on cephalopods by Pygoscelis papua and Arctocephalus gazelle at south Orkney Islands

The cephalopod diet of the gentoo penguin, Pygoscelis papua and the Ant− arctic fur seal, Arctocephalus gazella was comparatively analyzed at Laurie Island, South Orkney Islands. A total of 125 stomach samples were collected by the water off−loading method from gentoo penguins during the autumns of 1993, 1995 and 1996, and 39 fur seal scats were collected from mid March to April 1988. Cephalopods preyed upon by gentoo penguins were represented by 1974 beaks (1628 lower, 346 upper) which occurred in 50.4% of the samples. Lower beaks identified belonged exclusively to the squid Psychroteuthis glacialis. The mean lower rostral length (LRL) of these beaks was 1.1 mm (range 0.4– 1.8 mm). From the Antarctic fur seal scats 103 beaks (41 lower, 62 upper) were removed from 60.6% of scats which contained prey remains. The cephalopod species identified were Slosarczykovia circumantarctica and P. glacialis which constituted 78.8% and 21.1% in terms of numbers, respectively. The mean lower rostral length for S. circumantarctica was 2.7 mm (range 2.0–3.5 mm), while that of P. glacialis was 1.6 mm (range 1.0–2.5 mm). The foraging behaviour of the two top predators was analyzed and discussed according to the composition and size of their cephalopod prey