New insights into the mechanisms and sites of action of lamotrigine

This study was aimed at investigating the effects of lamotrigine (LTG) on electrically evoked field excitatory postsynaptic potentials (fEPSP) and population spikes in the CA1 hippocampal region of guinea pigs. The concentration response curves showed different actions of LTG on fEPSP and on population spikes. The data are in contrast to previous findings that suggest the drug acts primarily on presynaptic sites via a blockade of the release of excitatory amino acids, In the range of therapeutic plasma levels, synaptic transmission was not affected. Copyright (C) 2000 S. Karger AG, Basel

Validation of daily growth increments and estimation of growth rates of larval and early juvenile black skipjack, Euthynnus lineatus, using otoliths

ENGLISH: Increments in otoliths (sagittae) were examined, using light and scanning electron microscopy, to determine ages and estimate growth rates of larval and early-juvenile black skipjack, Euthynnus lineatus. Larvae and juveniles were collected between 1987 and 1989 from coastal waters of Panama in the eastern Pacific Ocean. Results from a laboratory experiment indicated that immersion for 6 and 12 hours in a 200 mg/L solution of tetracycline hydrochloride adequately marks otoliths and that increments are formed daily in the sagittae of postflexion larvae and early juveniles. Further, survival rates of tetracycline-treated fish were not significantly different from those of control fish. Growth rates were derived from length-age relationships of 218 field-collected specimens ranging in size from 5.7 to 20.3 mm SL. A growth rate of 0.70 mm/d was estimated from the weighted regression of standard length on age for all specimens. This rate lies within the range reported for larvae and early juveniles of other species of subtropical and tropical scombrids. Growth rates of postflexion larvae and early juveniles were not significantly different between the rainy season in July-August 1988 and the dry, upwelling season in January-February 1989. Growth was, however, significantly more variable for older individuals in July-August than in January-February, and may correspond, in part, to seasonal patchiness of prey. The growth rates of the otoliths relative to fish length were also not significantly different between seasons; however, the otoliths were larger relative to the lengths of fish collected in the rainy season, which may reflect slower growth during earlier larval stages. SPANISH: Se examinaron incrementos en otolitos (ságitas), usando microscopia de luz y de barrido electrónico, a fin de determinar la edad y estimar las tasas de crecimiento de barriletes negros, Euthynnus lineatus, larvales y juveniles tempranos. Entre 1987 y 1989 se capturaron larvas y juveniles en las aguas costeras de Panamá en el Océano Pacífico oriental. Los resultados de un experimento de laboratorio indicaron que una inmersión de 6 a 12 horas de duración en una solución de 200 mg/L de hidrocloro de tetraciclina marca los otolitos adecuadamente y que los incrementos se forman a diario en las ságitas de larvas en postflexión y juveniles tempranos. Además, las tasas de supervivencia de los peces tratados con tetraciclina no fueron significativamente diferentes a aquellas de los peces de control. Se calcularon las tasas de crecimiento a partir de las relaciones de talla-edad de 218 especímenes de TE entre 5.7 y 20.3 mm capturados en el mar. Se estimó.una tasa de crecimiento de 0.70 mm/día a partir de la regresión ponderada de talla estándar sobre edad para todos los especímenes. Esta tasa cae dentro del rango reportado para larvas y juveniles tempranos de otras especies de escómbridos subtropicales y tropicales. Las tasas de crecimiento de larvas en postflexión y juveniles tempranos no fueron significativamente diferentes entre la temporada de lluvias en julio-agosto de 1988 y la temporada de sequía y afloramiento en enero-febrero de 1989. Sin emoargo, el crecimiento fue significativamente más variable para los individuos de mayor edad en julio-agosto que en enero-febrero, y quizás corresponda parcialmente a la irregularidad temporal de la abundancia de presas. Las tasas de crecimiento de los otolitos en relación a la talla de los peces tampoco fueron significativamente diferentes entre temporadas; sin embargo, los otolitos eran más grandes en relación a la talla en peces capturados en la temporada de lluvias, lo cual podría reflejar crecimiento más lento durante las etapas larvales más tempranas. (PDF contains 42 pages.

Expanded-beam backside coupling interface for alignment-tolerant packaging of silicon photonics

We demonstrate an alignment-tolerant backside coupling interface in the O-band for silicon photonics by generating an optimized through-substrate (downward) directionality beam from a TE-mode grating coupler and hybrid integrating the chip with backside silicon microlenses to achieve expanded beam collimation. The key advantage of using such an expanded beam interface is an increased coupling tolerance to lateral and longitudinal misalignment. A 34 mu m beam diameter was achieved over a combined substrate thickness of 630 mu m which was then coupled to a thermally expanded core single-mode fiber to investigate the tolerances. A 1-dB fiber-to-microlens lateral alignment tolerance of 14 mu m and an angular alignment tolerance of 1 degrees was measured at a wavelength of 1310 nm. In addition, a large +/- 2.5 mu m 1-dB backside alignment accuracy was measured for the placement of microlens with respect to the grating. The radius of curvature of Si microlens to achieve a collimated beam was 480 mu m, and a 1-dB longitudinal alignment tolerance of 700 mu m was measured for coupling to a single-mode expanded core fiber. The relaxation in alignment tolerances make the demonstrated coupling interface suitable for chip-to-package or chip-to-board couplin

Natural spawning of four Epinephelus species in the laboratory

Natural spawnings of four Epinephelus species reared in the laboratory were observed from 1987 to 1992. These species are: E. summana, E. caeruleopunctatus, E. macrospilus and E. fuscoguttatus. Spawning was serial, usually occurring at night, on or 1-6 days after the new moon. Egg characteristics of these four species were compared. Fertilized egg and early larval development of E. summana and E. fuscoguttatus are discussed

The impact of SPARC on age-related cardiac dysfunction and fibrosis in Drosophila

Tissue fibrosis, an accumulation of extracellular matrix proteins such as collagen, accompanies cardiac ageing in humans and this is linked to an increased risk of cardiac failure. The mechanisms driving age-related tissue fibrosis and cardiac dysfunction are unclear, yet clinically important. Drosophila is amenable to the study of cardiac ageing as well as collagen deposition; however it is unclear whether collagen accumulates in the ageing Drosophila heart. This work examined collagen deposition and cardiac function in ageing Drosophila, in the context of reduced expression of collagen-interacting protein SPARC (Secreted Protein Acidic and Rich in Cysteine) an evolutionarily conserved protein linked with fibrosis. Heart function was measured using high frame rate videomicroscopy. Collagen deposition was monitored using a fluorescently-tagged collagen IV reporter (encoded by the Viking gene) and staining of the cardiac collagen, Pericardin. The Drosophila heart accumulated collagen IV and Pericardin as flies aged. Associated with this was a decline in cardiac function. SPARC heterozygous flies lived longer than controls and showed little to no age-related cardiac dysfunction. As flies of both genotypes aged, cardiac levels of collagen IV (Viking) and Pericardin increased similarly. Over-expression of SPARC caused cardiomyopathy and increased Pericardin deposition. The findings demonstrate that, like humans, the Drosophila heart develops a fibrosis-like phenotype as it ages. Although having no gross impact on collagen accumulation, reduced SPARC expression extended Drosophila lifespan and cardiac health span. It is proposed that cardiac fibrosis in humans may develop due to the activation of conserved mechanisms and that SPARC may mediate cardiac ageing by mechanisms more subtle than gross accumulation of collagen

Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides

Subwavelength grating (SWG) structures are an essential tool in silicon photonics, enabling the synthesis of metamaterials with a controllable refractive index. Here we propose, for the first time to the best of our knowledge, tilting the grating elements to gain control over the anisotropy of the metamaterial. Rigorous finite difference time domain simulations demonstrate that a 45° tilt results in an effective index variation on the fundamental TE mode of 0.23 refractive index units, whereas the change in the TM mode is 20 times smaller. Our simulation predictions are corroborated by experimental results. We furthermore propose an accurate theoretical model for designing tilted SWG structures based on rotated uniaxial crystals that is functional over a wide wavelength range and for both the fundamental and higher order modes. The proposed control over anisotropy opens promising venues in polarization management devices and transformation optics in silicon photonics.Universidad de Málaga (UMA); Ministerio de Economía y Competitividad (MINECO) (IJCI-2016-30484, TEC2015-71127-C2-R, TEC2016-80718-R); Ministerio de Educación, Cultura y Deporte (MECD) (FPU16/06762); European Regional Development Fund (ERDF); Comunidad de Madrid (SINFOTON-CM S2013/MIT-2790); European Association of National Metrology Institutes (EURAMET) (H2020-MSCA-RISE-2015:SENSIBLE, JRP-i22 14IND13 Photind)

Odorant Inhibition in Mosquito Olfaction.

How chemical signals are integrated at the peripheral sensory system of insects is still an enigma. Here we show that when coexpressed with Orco in Xenopus oocytes, an odorant receptor from the southern house mosquito, CquiOR32, generated inward (regular) currents when challenged with cyclohexanone and methyl salicylate, whereas eucalyptol and fenchone elicited inhibitory (upward) currents. Responses of CquiOR32-CquiOrco-expressing oocytes to odorants were reduced in a dose-dependent fashion by coapplication of inhibitors. This intrareceptor inhibition was also manifested in vivo in fruit flies expressing the mosquito receptor CquiOR32, as well in neurons on the antennae of the southern house mosquito. Likewise, an orthologue from the yellow fever mosquito, AaegOR71, showed intrareceptor inhibition in the Xenopus oocyte recording system and corresponding inhibition in antennal neurons. Inhibition was also manifested in mosquito behavior. Blood-seeking females were repelled by methyl salicylate, but repellence was significantly reduced when methyl salicylate was coapplied with eucalyptol

Diel variation in vertical distribution of an offshore ichthyoplankton community off the Oregon coast

We examined the diel ver-tical distribution, concentration, and community structure of ichthyoplank-ton from a single station 69 km off the central Oregon coast in the northeast Pacific Ocean. The 74 depth-stratified samples yielded 1571 fish larvae from 20 taxa, representing 11 families, and 128 fish eggs from 11 taxa within nine families. Dominant larval taxa were Sebastes spp. (rockfishes), Stenobra-chius leucopsarus (northern lampfish), Tarletonbeania crenularis (blue lan-ternfish), and Lyopsetta exilis (slender sole), and the dominant egg taxa were Sardinops sagax (Pacific sardine), Icichthys lockingtoni (medusafish), and Chauliodus macouni (Pacific viperfish). Larval concentrations generally increased from the surface to 50 m, then decreased with depth. Larval concentrations were higher at night than during the day, and there was evidence of larval diel vertical migration. Depth stratum was the most important factor explaining variability in larval and egg concentrations

Genetic and morphological differences between Sebastes vulpes and S. zonatus (Teleostei: Scorpaeniformes: Scorpaenidae)

The taxonomic status of Sebastes vulpes and S. zonatus were clarified by comprehensive genetic (amplif ied fragment length polymorphisms [AFLP] and mitochondrial DNA [mtDNA] variation) and morphological analyses on a total of 65 specimens collected from a single locality. A principal coordinate analysis based on 364 AFLP loci separated the specimens completely into two genetically distinct groups that corresponded to S. vulpes and S. zonatus according to body coloration and that indicated that they are reproductively isolated species. Significant morphological differences were also evident between the two groups; 1) separation by principal component analysis based on 31 measurements, and 2)separation according to differences in counts of gill rakers and dorsal-fin spines without basal scales, and in the frequencies of specimens with small scales on the lower jaw. Restriction of gene flow between the two groups was also indicated by the pairwise ΦST values estimated from variations in partial sequences from the mtDNA control region, although the minimum spanning network did not result in separation into distinct clades. The latter was likely due to incomplete lineage sorting between S. vulpes and S. zonatus owing to their recent speciation

An Introduction to Destructive Coordination

Polanyi (1944, [1957] 1968) has distinguished three 'patterns of social integration,' namely 'reciprocity', 'redistribution' and 'exchange.' This triad has provided the starting point for most subsequent discussion. Our purpose is to introduce a further type of coordination, the 'destructive mode of coordination'. This mode achieves coordination by intimidation, threat, and the use of non-institutionalized coercive means. Resources and human efforts are allocated in order to appropriate what other people produce. Two simple examples provide an introductory illustration, traffic circles (roundabouts) and prisons. Appropriation through pirating provides a further example of destructive coordination. More specifically, biopiracy (blood patenting) is discussed in order to clarify the relationship between destructive coordination and the institutionalization of property rights. Finally, we focus on the role of destructive coordination as a transitional mechanism that is supported by the institutional vacuum ultimately yielding to other modes of coordination.mode of coordination, destructive coordination, institutional vacuum, biopiracy, indeterminate property rights