Non-invasive genetic monitoring for the threatened valley elderberry longhorn beetle.

The valley elderberry longhorn beetle (VELB), Desmocerus californicus dimorphus (Coleoptera: Cerambycidae), is a federally threatened subspecies endemic to the Central Valley of California. The VELB range partially overlaps with that of its morphologically similar sister taxon, the California elderberry longhorn beetle (CELB), Desmocerus californicus californicus (Coleoptera: Cerambycidae). Current surveying methods are limited to visual identification of larval exit holes in the VELB/CELB host plant, elderberry (Sambucus spp.), into which larvae bore and excavate feeding galleries. Unbiased genetic approaches could provide a much-needed complementary approach that has more precision than relying on visual inspection of exit holes. In this study we developed a DNA sequencing-based method for indirect detection of VELB/CELB from frass (insect fecal matter), which can be easily and non-invasively collected from exit holes. Frass samples were collected from 37 locations and the 12S and 16S mitochondrial genes were partially sequenced using nested PCR amplification. Three frass-derived sequences showed 100% sequence identity to VELB/CELB barcode references from museum specimens sequenced for this study. Database queries of frass-derived sequences also revealed high similarity to common occupants of old VELB feeding galleries, including earwigs, flies, and other beetles. Overall, this non-invasive approach is a first step towards a genetic assay that could augment existing VELB monitoring and accurately discriminate between VELB, CELB, and other insects. Furthermore, a phylogenetic analysis of 12S and 16S data from museum specimens revealed evidence for the existence of a previously unrecognized, genetically distinct CELB subpopulation in southern California

Solar-driven reduction of CO₂:from homogeneous to heterogeneous catalytic systems

Rapidly increasing levels of atmospheric carbon dioxide and their damaging impact on the global climate system raise doubts about the sustainability of the fossil resource based energy system. Meanwhile, raising living standards and increasing global population lead to an ever growing need for energy. Renewable energy sources are believed to present a solution to these problems with the sheer abundance of solar energy showing particular promise to fulfill the world's energy needs. However, for large scale application of solar energy to be possible, the problem of its storage has to be addressed. The insufficient flexibility of present-day storage technologies has led to the quest for producing solar fuels, centering on hydrogen as a fuel in a prospective hydrogen economy. Nevertheless, the gaseous state, low volumetric energy density and explosive nature of hydrogen makes it a challenging fuel for practical applications. Using solar energy to produce carbon-based liquid fuels solves these challenges, closes the anthropogenic carbon cycle and allows for the continued utilization of existing infrastructures. A promising method for the production of such fuels consists in the photoelectrochemical and electrochemical conversion of carbon dioxide. In this thesis, both methods are investigated using molecular homogeneous catalysts and heterogeneous systems. The photoelectrochemical reduction of carbon dioxide on TiO2-protected Cu2O photocathodes was investigated using a rhenium bipyridyl catalyst in solution. Important charge transport limitations were encountered, which could be overcome by the addition of protic additives to the electrolyte. Improving on this result, the molecular catalyst was covalently immobilized on the TiO2 surface of the photocathode by modifying the bipyridyl ligand with a phosphonate binding group. A nanostructure of TiO2 was needed to support sufficient catalyst to sustain the photocurrent generated by the Cu2O photoelectrode. The complete device showed photocurrents exceeding 2.5 mA cm-2 and large faradaic efficiency for the production of CO. Moving toward heterogeneous catalysis, the promotion of the CO2 to CO conversion reaction on silver surfaces by imidazolium cations was investigated. Replacing the imidazolium C2 proton with a phenyl substituent led to an enhancement of the co-catalytic effect. Replacing the C4 and C5 protons with methyl groups, however, suppressed the catalysis-promoting effect of the imidazolium salt for different C2 substituents and led to new insights into the role of imidazolium. The unassisted solar-driven splitting of CO2 into CO and O2 was demonstrated using water as electron source. This was achieved by the use of a porous gold cathode and an IrO2 anode, driven by three methylammonium lead iodide perovskite solar cells in series. Extended operation over 18 h was shown, achieving a solar to CO efficiency exceeding 6.5 %. Atomic layer deposition (ALD) modification of CuO nanowire cathodes with SnO2 was investigated, leading to striking impacts on the catalytic selectivity of this system. In an aqueous electrolyte, bare CuO led to the production of a wide spectrum of products, which was modified to the production of CO with high selectivity upon ALD modification. By exploiting the oxygen evolving activity of SnO2-coated CuO, a low cost bifunctional system was constructed, achieving sustained solar-driven production of CO with up to 13.4% efficiency

Molecular Engineering of Potent Sensitizers for Very Efficient Light Harvesting in Thin-Film Solid-State Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) have shown significant potential for indoor arid building integrated photovoltaic applications. Herein we present three new D-A-pi-A organic sensitizers, XY1, XY2, and XY3, that exhibit high molar extinction coefficients and a broad absorption range. Molecular modifications of these dyes, featuring a benzothiadiazole (BTZ) auxiliary acceptor, were achieved by introducing a thiophene heterocycle as well as by shifting the, position of BTZ on the conjugated bridge. The ensuing high molar absorption coefficients enabled the fabrication of highly efficient thin-film solid-state DSSCs with only 1.3 mu m mesoporous TiO2 layer. XY2 with a molar extinction coefficient of 6.66 X 10(4) M-1 cm(-1) at 578 nm led to the best photovoltaic performance of 7.51%

Polymer-based photocathodes with a solution-processable cuprous iodide anode layer and a polyethyleneimine protective coating

Organic semiconductors are proven to efficiently drive photoelectrochemical water splitting

Carbon nanotubes as electronic interconnects in solid acid fuel cell electrodes

Carbon nanotubes have been explored as interconnects in solid acid fuel cells to improve the link between nanoscale Pt catalyst particles and macroscale current collectors. The nanotubes were grown by chemical vapor deposition on carbon paper substrates, using nickel nanoparticles as the catalyst, and were characterized using scanning electron microscopy and Raman spectroscopy. The composite electrode material, consisting of CsH_2PO_4, platinum nanoparticles, and platinum on carbon-black nanoparticles, was deposited onto the nanotube-overgrown carbon paper by electrospraying, forming a highly porous, fractal structure. AC impedance spectroscopy in a symmetric cell configuration revealed a significant reduction of the electrode impedance as compared to similarly prepared electrodes without carbon nanotubes

Physiological Correlates of Volunteering

We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation

Electrocatalytic Scission of Unactivated C(sp3)−C(sp3) Bonds Through Real-Time Manipulation of Surface-Bound Intermediates

We demonstrate an electrocatalytic approach to cleave the C(sp3)-C(sp3) bond in ethane at room temperature. This reaction is enabled by time-dependent electrode potential sequences, combined with monolayer-sensitive in-situ analysis, which allows us to gain independent control over ethane adsorption, C-C bond fragmentation, and methane desorption. Importantly, our approach allowed us to vary the electrode potential to promote the fragmentation of ethane after it is bound to the catalyst surface, resulting in unprecedented control over the selectivity of this alkane transformation reaction. Steering the transformation of intermediates after adsorption constitutes an underexplored lever of control in catalysis. As such, our findings widen the parameter space for catalytic reaction engineering and open the door to future sustainable synthesis and energy storage technologies