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How and when Earth’s volatile content was established is controversial with several mechanisms postulated, including planetesimal evaporation, core formation and the late delivery of undifferentiated chondrite-like materials. The isotopes of volatile elements such as sulfur can be fractionated during planetary accretion and differentiation and thus are potential tracers of these processes. Using first-principles calculations, we examine sulfur isotope fractionation during core formation and planetesimal evaporation. We find no measurable sulfur isotope fractionation between silicate and metallic melts at core-forming conditions, indicating that the observed light sulfur isotope composition of the bulk silicate Earth relative to chondrites cannot be explained by metal–silicate fractionation. Our thermodynamic calculations show that sulfur evaporates mostly as H2S during planetesimal evaporation when nebular H2 is present. The observed bulk Earth sulfur isotope signature and abundance can be reproduced by evaporative loss of about 90% sulfur mainly as H2S from molten planetesimals before nebular H2 is dissipated. The heavy sulfur isotope composition of the Moon relative to the Earth is consistent with evaporative sulfur loss under 94–98% saturation condition during the Moon-forming giant impact. In summary, volatile evaporation from molten planetesimals before Earth’s formation probably played a key role in establishing Earth’s volatile element content. Earth’s volatile element content was established largely by volatile evaporation from molten planetesimals before Earth’s formation, according to first-principles calculations and examination of sulfur isotope fractionation.

Solution-processable conductive polymers are advantageous materials for making inexpensive, electrical junctions to crystalline semiconductors. We have investigated methods to improve the device performance of hybrid solar cells made from n-type silicon and a conductive polymer glue based on a blend of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and D-sorbitol. The PEDOT:PSS blend behaves like a high work function metal creating a Schottky-type junction. The addition of D-sorbitol increases PEDOT:PSS conductivity and provides adhesive properties, allowing the top contact of the solar cell to be laminated onto the silicon substrate. Unfortunately, the addition of the D-sorbitol to the PEDOT:PSS significantly alters the shape of the measured current-voltage performance curve of a crystalline silicon (n-Si)/PEDOT:PSS junction. Under illumination, this results in a decline in the fill factor (FF) and a drop in photocurrent density (J sc) compared to PEDOT:PSS-only devices. We have discovered that the decline in device performance is likely due to surface trap states caused by D-sorbitol/silicon interaction and/or silicon oxidation. X-ray photoelectron spectroscopic (XPS) analysis shows that surface oxidation quickens, and possible silicon surface functionalization with D-sorbitol occurs while processing the D-sorbitol/PEDOT:PSS contact on H-terminated surfaces. To overcome these interface issues, the silicon surface was chemically modified using surface methylation, making it insensitive to D-sorbitol/silicon interactions and surface oxidation during the processing of the PEDOT:PSS polymer blend contact. This also enabled the crystalline silicon (n-Si)/s-PEDOT:PSS device performance to be maintained for longer periods. Using a silicon surface methylation strategy, good device performance could be achieved without changing the adhesive properties of D-sorbitol/PEDOT:PSS polymer blend.

Organic electronics has developed rapidly over the past 40 years. In 1977, a seminal discovery was reported that showed that a polymer known as polyacetylene could conduct electricity as well as metals could. This was a groundbreaking discovery that led to a Nobel Prize in Chemistry in 2000. The polymers that are used in organic electronics have now been widely studied for use in organic solar cells (OSCs), organic field effect transistors (OFETs), printable electronics, flexible electronics, antistatic coatings, actuators, and more recently in bioelectronics. In particular, the utility of organic electronics is seen in the commercial success of using organic electronic materials in organic light-emitting diodes (OLEDs) where OLED displays can be seen in mobile phones and as flat panel displays. In this paper, we provide a tutorial targeting upper secondary students describing how these special classes of polymers function, and how they can be synthesized. The paper further discusses the use of these materials in two applications: organic solar cells and organic light-emitting diodes. The paper ends with a brief discussion about hands-on activities that can be carried out in the upper secondary student science classroom.

Fundamental properties of conjugated copolymers are sensitively linked to their constitution and features of their repeat unit design that govern assembly and organization across multiple length scales, ultimately impacting device performance. Herein we report the efficient synthesis and characterization, and optical, electrochemical and transport properties of complementary pairs of nucleobase-functionalized, fully conjugated copolymers based on benzo[1,2-b:4,5-b′]-dithiophene (BDT) and 3-hexylthiophene (3hT), which is a quintessential low bandgap polymer. Stille cross-coupling polymerizations enable access to high molecular weight, alternating copolymers of modest dispersity containing pendant adenine or thymine groups in each repeating unit, which provide the capacity to direct molecular assembly. Variations in nucleobase type and design of alkyl side chains on BDT units give rise to a strongly red-shifted absorbance onset for the copolymers containing thymine and adenine functionality in comparison to solution and dried films. Higher hole mobilities were also observed and attributed to the tendency of the nucleobase inclusion to heighten organization. The influence of the nucleobases on the organization is further revealed when thermal pre-treatment is used during film formation: modest heating before casting the non-functionalized BDT-3hT copolymers leads to increases in the mobility, optical absorbance and fluorescence, while copolymers with adenine or thymine pendant groups do not show analogous improvements, suggesting that the nucleobases have promoted nanoscale organization, which is consistent with assessments of hydrogen bonding interactions. Given the structure-directing ability of nucleobases through hydrogen bonding, π-stacking, and complementary base pairing, these novel materials engender myriad opportunities to examine how specific molecular-level interactions that cue self-assembly affect optoelectronic properties and device-level performance.

Made available in DSpace on 2022-05-01T11:07:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 These recommendations are specifically for polymers and polymer systems showing a significant response to an electromagnetic field or one of its components (electric field or magnetic field), i.e., for electromagnetic-field-responsive polymer materials. The structures, processes, phenomena and quantities relating to this interdisciplinary field of materials science and technology are herein defined. Definitions are unambiguously explained and harmonized for wide acceptance by the chemistry, physics, polymer and materials science communities. A survey of typical electromagnetic-field-responsive polymers is included. Department of Physical and Macromolecular Chemistry Faculty of Sciences Charles University, Albertov 2030 DF-FC UNESP - Universidade Estadual Paulista, Av. Eng. Luiz Edmundo Carrijo Coube 14-01 Institut des Science Analytiques et Physico-Chimie Pour l'Environnement et les Materiaux CNRS Univ Pau and Pays Adour University of Kent Pi-Conjugated Polymer Unit Okinawa Institute of Science and Technology, Onna-son Organisation Moléculaire Evolution et Matériaux Fluores UMR CNRS 5073 Laboratoire de Chimie Macromoléculaire Université Montpellier II Science et Techniques du Languedoc, Place Eugène Bataillon, Cedex 5 Department of Materials Centre of Plastic Electronics (CPE) Imperial College, Exhibition Road Department of Chemistry University of North Carolina at Charlotte DF-FC UNESP - Universidade Estadual Paulista, Av. Eng. Luiz Edmundo Carrijo Coube 14-01

A family of asymmetric thiazolo[5,4-d]thiazole (TTz) fluorescent dye sensors has been developed, and their photophysical sensing properties are reported. The π-conjugated, TTz-bridged compounds are synthesized via a single-step, double condensation/oxidation of dithiooxamide and two different aromatic aldehydes: one with strong electron-donating characteristics and one with strong electron-accepting characteristics. The four reported dyes include electron-donating moieties (N,N-dibutylaniline and N,N-diphenylaniline) matched with three different electron-accepting moieties (pyridine, benzoic acid, and carboxaldehyde). The asymmetric TTz derivatives exhibit strong solvatofluorochromism with Stokes shifts between 0.269 and 0.750 eV (2270 and 6050 cm-1) and transition dipole moments (Δμ = 13-18 D) that are among the highest reported for push-pull dyes. Fluorescence quantum yields are as high as 0.93 in nonpolar solvents, and the fluorescence lifetimes (τF) vary from 1.50 to 3.01 ns depending on the solvent polarity. In addition, thermofluorochromic studies and spectrophotometric acid titrations were performed and indicate the possibility of using these dyes as temperature and/or acid sensors. In vitro cell studies indicate good cell membrane localization, negligible cytotoxicity, promising voltage sensitivities, and photostabilities that are 4 times higher than comparable dyes. Their ease of synthesis and purification, remarkable photophysical properties, and chemically sensitive TTz π-bridge make these asymmetric dye derivatives attractive for environmental and biological sensing or similar molecular optoelectronic applications.

Photoinduced electron and energy transfer through preorganized chromophore, donor, and acceptor arrays are key to light-harvesting capabilities of photosynthetic plants and bacteria. Mimicking the ...

This paper provides a list of the most important terms from all areas of polymer science including polymer chemistry, polymer physics, polymer technology and polymer properties. These have been assembled into a representative list of terms that serves as an IUPAC recommended list of keywords for polymer science.

We report on laser-heated diamond anvil cell (LHDAC) experiments in the FeO–MgO–SiO2–CO2 (FMSC) and CaO–MgO–SiO2–CO2 (CMSC) systems at lower mantle pressures designed to test for decarbonation and diamond forming reactions. Sub-solidus phase relations based on synthesis experiments are reported in the pressure range of ∼35 to 90 GPa at temperatures of ∼1600 to 2200 K. Ternary bulk compositions comprised of mixtures of carbonate and silica are constructed such that decarbonation reactions produce non-ternary phases (e.g. bridgmanite, Ca-perovskite, diamond, CO2–V), and synchrotron X-ray diffraction and micro-Raman spectroscopy are used to identify the appearance of reaction products. We find that carbonate phases in these two systems react with silica to form bridgmanite ±Ca-perovskite + CO2 at pressures in the range of ∼40 to 70 GPa and 1600 to 1900 K in decarbonation reactions with negative Clapeyron slopes. Our results show that decarbonation reactions form an impenetrable barrier to subduction of carbonate in oceanic crust to depths in the mantle greater than ∼1500 km. We also identify carbonate and CO2–V dissociation reactions that form diamond plus oxygen. On the basis of the observed decarbonation reactions we predict that the ultimate fate of carbonate in oceanic crust subducted into the deep lower mantle is in the form of refractory diamond in the deepest lower mantle along a slab geotherm and throughout the lower mantle along a mantle geotherm. Diamond produced in oceanic crust by subsolidus decarbonation is refractory and immobile and can be stored at the base of the mantle over long timescales, potentially returning to the surface in OIB magmas associated with deep mantle plumes.

Previous work has shown that Mo isotopes measurably fractionate between metal and silicate liquids, even at temperatures appropriate for core formation. However, the effect of variations in the structural environment of Mo in the silicate liquid, especially as a function of valence state, on Mo isotope fractionation remained poorly explored. We have investigated the role of valence state in metal-silicate experiments in a gas-controlled furnace at 1400 °C and at oxygen fugacities between 10−12.7 and 10–9.9, i.e. between three and 0.2 log units below the iron-wüstite buffer. Two sets of experiments were performed, both with a silicate liquid in the CaO-Al2O3-SiO2 system. One set used molybdenum metal wire loops as the metal source, the other liquid gold alloyed with 2.5 wt% Mo contained in silica glass tubes. X-ray absorption near-edge spectroscopy analysis indicates that Mo6+/ΣMo in the silicate glasses varies between 0.24 and 0.77 at oxygen fugacities of 10–12.0 and 10–9.9 in the wire loop experiments and between 0.15 and 0.48 at 10–11.4 and 10–9.9 in the experiments with Au-Mo alloys. Double-spiked analysis of Mo isotope compositions furthermore shows that Mo isotope fractionation between metal and silicate is a linear function of Mo6+/ΣMo in the silicate glasses, with a difference of 0.51‰ in 98Mo/95Mo between purely Mo4+-bearing and purely Mo6+-bearing silicate liquid. The former is octahedrally and the latter tetrahedrally coordinated. Our study implies that previous experimental work contained a mixture of Mo4+ and Mo6+ species in the silicate liquid. Our refined parameterisation for Mo isotope fractionation between metal and silicate can be described as Δ98/95Mometal–silicate=[Formula presented] Molybdenum isotope ratios therefore have potential as a proxy to constrain the oxygen fugacity during core formation on planetary bodies if the parameterisation of Mo6+/ΣMo variation with oxygen fugacity is expanded, for instance to include iron-bearing systems. On Earth literature data indicate that the upper mantle is depleted in heavy Mo isotopes relative to the bulk Earth, as represented by chondrites. As previously highlighted, this difference is most likely not caused by core formation, which either enriches the mantle in heavy Mo isotopes or causes no significant fractionation, depending on temperature and, as we determined here, Mo6+ content. We reaffirm that core formation does not account for the Mo isotope composition of the modern upper mantle, which may instead reflect the effect of fractionation during subduction as part of global plate recycling.

The arbuscular mycorrhizal (AM) symbiosis is a widespread underground interaction of mutual benefit between plant roots and a specialized clade of fungi, which helps plants in the acquisition of minerals from nutrient-poor soils. Arbuscules are tiny fungal organs growing inside root cortex cells to release minerals collected from soils. A yellow colouration of roots strongly colonized by AM fungi has been attributed to the accumulation of a linear C14 apocarotenoid called mycorradicin. It is accompanied by the formation of cyclic C13 α-ionol apocarotenoids, which are usually glycosylated. Both apocarotenoids originate from the enzymatic cleavage of a common carotenoid precursor, presumably zeaxanthin carried out in two consecutive steps by CCD7 and CCD1. These apocarotenoids are formed specifically in root cells hosting fungal arbuscules, and there are now arguments that at least one of them may be involved in the control of the arbuscule life span by the plant. The universal presence of C13 α-ionol derivatives, but not of C14 mycorradicin, and other findings, argue for a role of C13 compounds in such processes. Certain C13 derivatives appear to be transported from mycorrhizal roots to leaves, which can be exploited for an aboveground monitoring of the underground mycorrhization status of plants.

Strigolactones (SLs) were first identified as rhizosphere signals, which stimulate seed germination of Striga root parasitic weeds. SL biosynthesis starts from β-carotene and involves two consecutive carotenoid cleavage steps by CCD7 and CCD8 followed by further oxidations. This results in a four-ring structure, in which the methylbutenolide D-ring is essential for biological activity. Developing strategies against parasite infestations is still a major driver of research, but a plenitude of new aspects of SL actions have emerged, making SLs a very active field of research. The overarching theme for SL functions seems to be their signalling role in mineral nutrient stress responses. SL formation is induced by mineral nutrient starvation accompanied by transcriptional activation of biosynthetic genes. Elevated SL levels result in a modified shoot architecture (hormone action as a shoot branching inhibitor) and in alterations in root development. Elevated SL exudation into the rhizosphere supports the ancient interaction of roots with arbuscular mycorrhizal fungal symbionts helping plants in mineral nutrient acquisition – a signal subsequently captured by the parasites. SL signal perception in plants has been studied extensively, elucidating a large receptor/F-box protein complex. SL analogues are being chemically synthesized for use in anti-parasite measures, and in other applications.

A neutral hexacoordinate silicon complex containing two 2,6-bis(benzimidazol-2'-yl)pyridine (bzimpy) ligands has been synthesized and explored as a potential electron transport layer and electroluminescent layer in organic electronic devices. The air and water stable complex is fluorescent in solution with a λmax = 510 nm and a QY = 57%. Thin films grown via thermal evaporation also fluoresce and possess an average electron mobility of 6.3 × 10-5 cm2 V-1 s-1. An ITO/Si(bzimpy)2/Al device exhibits electroluminescence with λmax = 560 nm.

Geophysical and geochemical evidence suggests that Earth's core is predominantly made of iron (or iron-nickel alloy) with several percent of light elements. However, Earth's solid inner core transmits shear waves at a much lower velocity than expected from mineralogical models that are consistent with geochemical constraints. Here we investigate the effect of hydrogen on the elastic properties of iron and iron-silicon alloys using ab initio molecular dynamic simulations. We find that these H-bearing alloys maintain a superionic state under inner-core conditions and that their shear moduli exhibit a strong shear softening due to the superionic effect, with a corresponding reduction in V S . Several hcp-iron-silicon-hydrogen compositions can explain the observed density, V P , V S , and Poisson's ratio of the inner core simultaneously. Our results indicate that hydrogen is a significant component of the Earth's core, and that it may contain at least four ocean masses of water. This indicates that the Earth may have accreted wet and obtained its water from chondritic and/or nebular materials before or during core formation.

To improve polymer education for 9–12 and undergraduate students, a plastic electronics laboratory kit using polymer semiconductors has been developed. The three-module kit and curriculum use polymer semiconductors to provide hands-on inquiry activities with overlapping themes of electrical conductivity, light emission, and light-harvesting solar energy conversion. Many of these themes are critical to contemporary polymer molecular electronics research. The kit includes modules to synthesize and evaluate the electrical properties of conductive colloidal polyaniline (PAni), to construct a polymer light-emitting diode using poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), and to build a polymer solar cell using MEH-PPV and nanoparticulate TiO2. Designed initially for high school science classrooms, the activities developed also meet new ACS undergraduate education requirements for macromolecular, supramolecular, and nanoscale systems in the curriculum and can be used in undergraduate tea...

The synthesis, electrochemical, and photophysical characterization of N,N′-dialkylated and N,N′-dibenzylated dipyridinium thiazolo[5,4-d]thiazole derivatives are reported. The thiazolothiazole viologens exhibit strong blue fluorescence with high quantum yields between 0.8–0.96. The dioctyl, dimethyl, and dibenzyl derivatives also show distinctive and reversible yellow to dark blue electrochromism at low reduction potentials. The fused bicyclic thiazolo[5,4-d]thiazole heterocycle allows the alkylated pyridinium groups to remain planar, strongly affecting their electrochemical properties. The singlet quantum yield is greatly enhanced with quaternarization of the peripheral 4-pyridyl groups (ΦF increases from 0.22 to 0.96) while long-lived fluorescence lifetimes were observed between 1.8–2.4 ns. The thiazolothiazole viologens have been characterized using cyclic voltammetry, UV–visible absorbance and fluorescence spectroscopy, spectroelectrochemistry, and time-resolved photoluminescence. The electrochromic p...

Creating new building blocks for donor–acceptor conjugated systems is an important task for continued development of materials for organic electronics. Purines were introduced into small-molecule π-conjugated systems via Stille cross-coupling using stannylated derivatives of benzodithiophene, thiophene, or dithienylbenzothiadiazole to generate a series of “purine–π–purine” chromophores having high thermal stability, long excited-state lifetimes, and high quantum yields. Photophysical and electrochemical property characterization indicate that depending on the choice of a conjugated bridging unit, purines behave as either an electron-donating or an electron-accepting unit in these small-molecule donor–acceptor chromophores. Specifically, while purine chromophores do not exhibit charge transfer character when linked to a thiophene unit, purinyl units act as a weak acceptor when coupled with benzodithiophene and as a weak donor when coupled with dithienylbenzothiadiazole. In addition to fundamental insights into the molecular design of purine-based chromophores and their charge-transfer character, the results and synthetic tailorability of purines suggest that they may be compelling building blocks in conjugated materials for optical and electronic devices and sensors.

A new Ti-bearing bridgmanite-like phase with a threefold commensurate superstructure of the ideal MgSiO 3 -perovskite structure was observed in a [Mg 5/6 Al 1/6 ][Si 1/2 Ti 1/3 Al 1/6 ]O 3 crystal synthesized in the model system Mg 3 Al 2 Si 3 O 12 –MgTiO 3 at 20 GPa and 1600 °C. The compound was found to be orthorhombic, space group Pnma , with lattice parameters a = 14.767(3), b = 6.958(1), c = 4.812(1) A, V = 494.4(2) A 3 , which represents a 3 a × b × c superstructure of the typical Pnma perovskite structure. The structure was refined to R = 0.024 using 846 independent reflections. The superstructure mainly arises from the ordering of titanium in one of the octahedral positions. Crystal-chemical details of the different polyhedra in the superstructure are discussed in comparison to pure MgSiO 3 . This is the first documented superstructure of a bridgmanite phase, and Ti-rich bridgmanite in the lower mantle arising from local Ti-enrichments may exhibit different physical properties and elemental partitioning behavior from Ti-poor, peridotitic bridgmanite. The study also shows that large amounts of Ti can stabilize bridgmanite-like compounds at considerably lower pressure than lower mantle conditions.

PURPOSE To analyze the clinical fit of monolithic zirconia single crowns (MZSCs) in a prospective cohort study. MATERIALS AND METHODS A total of 30 posterior teeth were restored with MZSCs. Silicone replicas were made to measure the clinical fit using a stereomicroscope. Measurements were conducted at 17 points per crown at the marginal and occlusal surfaces. RESULTS The mean clinical fit was 0.104 mm at the crown margin and 0.101 mm at the occlusal surface. Measured distances at the marginal and occlusal surfaces were comparable. CONCLUSION MZSCs showed acceptable clinical fit.

Mutations in the forkhead box C1 gene (FOXC1) cause Axenfeld-Rieger syndrome (ARS). Here, we investigated the effect of four ARS missense variants on FOXC1 structure and function, and examined the predictive value of four in silico programs for all 31 FOXC1 missense variants identified to date. Molecular modeling of the FOXC1 forkhead domain predicts that c.402G> A (p.C135Y) alters FOXC1's structure. In contrast, c.378A> G (p.H128R) and c.481A> G (p.M161V) are not predicted to change FOXC1's structure. Functional analysis indicates that p.H128R reduced DNA binding, transactivation, nuclear localization, and has a longer protein half-life than normal. p.C135Y significantly disrupts FOXC1's DNA binding, transactivation, and nuclear localization. p.M161V reduces transactivation capacity without affecting other FOXC1 functions. C.1103C> A (p.T368N) is indistinguishable from wild-type FOXC1 in all tests, consistent with being a rare benign variant. Comparison of these four variants, plus 18 previously characterized FOXC1 missense variants, with predictions from four commonly used in silico bioinformatics programs indicated that sorting intolerant from tolerant (SIFT), polymorphism phenotyping (PolyPhen-2), and MutPred can sensitively identify as pathogenic only FOXC1 mutations with significant functional defects. This information was used to predict, as disease-causing, nine additional FOXC1 missense variations. Importantly, our results indicate SIFT, PolyPhen-2, and MutPred can reliably be used to predict missense variant pathogenicity for forkhead transcription factors.

The trace element compositions of inclusions in sub-lithospheric diamonds from the Juina-5 kimberlite, Brazil, are presented. Literature data for mineral/melt partition coefficients were collated, refitted and employed to interpret inclusion compositions. As part of this process an updated empirical model for predicting the partitioning behaviour of trivalent cations for garnet–melt equilibrium calibrated using data from 73 garnet-melt pairs is presented. High levels of trace element enrichment in inclusions interpreted as former calcium silicate perovskite and majoritic garnet preclude their origin as fragments of an ambient deep mantle assemblage. Inclusions believed to represent former bridgmanite minerals also display a modest degree of enrichment relative to mantle phases. The trace element compositions of ‘NAL’ and ‘CF phase’ minerals are also reported. Negative Eu, Ce, and Y/Ho anomalies alongside depletions of Sr, Hf and Zr in many inclusions are suggestive of formation from a low-degree carbonatitic melt of subducted oceanic crust. Observed enrichments in garnet and ‘calcium perovskite’ inclusions limit depths of melting to less than ~ 600 km, prior to calcium perovskite saturation in subducting assemblages. Less enriched inclusions in sub-lithospheric diamonds from other global localities may represent deeper diamond formation. Modelled source rock compositions that are capable of producing melts in equilibrium with Juina-5 ‘calcium perovskite’ and majorite inclusions are consistent with subducted MORB. Global majorite inclusion compositions suggest a common process is responsible for the formation of many superdeep diamonds, irrespective of geographic locality. Global transition zone inclusion compositions are reproduced by fractional crystallisation from a single parent melt, suggesting that they record the crystallisation sequence and melt evolution during this interaction of slab melts with ambient mantle. All observations are consistent with the previous hypothesis that many superdeep diamonds are created as slab-derived carbonatites interact with peridotitic mantle in the transition zone.

We describe the collection of both time-resolved and steady-state micro-photoluminescence data from solution-grown single crystals of 5,15-bis(4-carbomethoxyphenyl)porphyrin (BCM 2 PP). Linking molecular orientation and structure with excited-state dynamics is crucial for engineering efficient organic solar cells, light-emitting diodes, and related molecular electronics. Photoluminescence features of single porphyrin crystals were imaged using a laser scanning confocal microscope equipped with time-correlated single photon counting (TCSPC). We show enhanced exciton lifetimes ( τ s1 = 2.6 ns) and stronger steady-state emission in crystalline BCM 2 PP samples relative to semicrystalline thin films ( τ s1 = 1.8 ns).

Prostaglandins are small pro-inflammatory molecules derived from arachidonic acid that play roles in a multitude of biological processes including, but not limited to, inflammation, pain modulation, allergies, and bone formation. Prostaglandin analogues are the front-line medications for the treatment of glaucoma, a condition resulting in blindness due to the death of retinal ganglion cells. These drugs act by lowering intraocular pressure (IOP), a major risk factor for glaucoma. The currently used prostaglandin analogues (latanoprost, bimatoprost, tafluprost, and travoprost) mimic PGF2 and target one of the prostaglandin receptors (FP), though research into harnessing the other receptors using compounds like Sulprostone (EP3 receptor), or Iloprost (IP receptor) are currently ongoing. In this review, we summarize the research into each of the prostaglandin molecules (PGD2, PGE2, PGF2, PGI2, TXA2) and their respective receptors (DP, EP1, 2, 3, 4, FP, IP). We examine the modes of action of each of these receptors, their expression, their role in aqueous humour production and outflow within the eye, as well as their roles as medications for the treatment of glaucoma.

The effects of molecular arrangement on the singlet exciton diffusion properties of free-base carboalkoxyphenylporphyrins containing a variety of alkyl substituents were investigated in solution-cast thin films. Exciton diffusivity was calculated using relative quenching efficiencies (Q) obtained by measuring the singlet photoluminescent decay lifetime PL(t) of pristine porphyrin films and films doped with 0.06–0.2% volume fraction of [6,6]-phenyl-C61-butryic acid methyl ester (PCBM). The quenching efficiency and PL lifetime decay data was used in a 3D exciton diffusion Monte Carlo simulation model to extract the exciton diffusion coefficient (D) and diffusion length (LD). Five carboalkoxyphenyl porphyrins (TCAPPs) were synthesized and analyzed in solution-cast thin films, tetra(4-carbomethoxyphenyl)porphyrin (TCM4PP), tetra(4-carbobutoxyphenyl) porphyrin (TCB4PP), tetra(4-carbohexoxyphenyl)porphyrin (TCH4PP), tetra(4-carbo-2-ethylhexoxyphenyl) porphyrin (TCEH4PP), and tetra(4-carbooctoxyphenyl)porphyrin (TCO4PP). Longer alkyl chain derivatives yielded increased PL decay lifetimes and extended the exciton diffusion lengths (LD) for octyl (TCO4PP) and hexyl (TCH4PP) porphyrin derivatives. We observed an increase in the LD from 15 nm for TCM4PP to 25 nm for TCH4PP, while a branched alkyl chain derivative (TCEH4PP) showed the lowest LD of 14 nm. UV-Vis and XRD data indicate that molecular organization is strongly dependent upon the peripheral carboalkoxy chain, and that nematic molecular organization resulted in an increase in the exciton diffusion length. Our findings are an important step toward a deeper understanding of the exciton diffusivity and molecular packing relationship of simple free-base porphyrins.

We present a theoretical model of the stability and migration of carbonate-rich melts to test whether they can explain seismic low-velocity layers (LVLs) observed above stalled slabs in several convergent tectonic settings. The LVLs, located atop the mantle transition zone, contain small (∼1 vol%) amounts of partial melt, possibly derived from melting of subducted carbonate-bearing oceanic crust. Petrological and geochemical evidence from inclusions in superdeep diamonds supports the existence of slab-derived carbonate melt, which may potentially explain the origin of the observed melt in the LVL. However, the presumptive reducing nature of the ambient mantle can be an impediment to the stability of carbonated melt. To reconcile this apparent contradiction, we test the stability and migration rates of carbonate-rich melts atop a stalled slab as a function of melt percolation, redox freezing, amount of carbon supplied by subduction, and the metallic Fe concentration in the mantle. Our results demonstrate that carbonate-rich melts in the LVL can potentially survive redox freezing over long geological time scales. We also show that the amount of subducted carbon exerts a stronger influence on the stability of carbonate melt than does the mantle redox condition. Concentration dependent melt density leads to rapid melt propagation through channels while a constant melt density causes melt to migrate as a planar front. Our calculations suggest that the LVLs can sequester significant fractions of carbon transported to the mantle by subduction.

Strigolactones (SLs) are apocarotenoid phytohormones synthesized from carotenoid precursors. They are produced most abundantly in roots for exudation into the rhizosphere to cope with mineral nutrient starvation through support of root symbionts. Abscisic acid (ABA) is another apocarotenoid phytohormone synthesized in roots, which is involved in responses to abiotic stress. Typically low carotenoid levels in roots raise the issue of precursor supply for the biosynthesis of these two apocarotenoids in this organ. Increased ABA levels upon abiotic stress in Poaceae roots are known to be supported by a particular isoform of phytoene synthase (PSY), catalyzing the rate-limiting step in carotenogenesis. Here we report on novel PSY3 isogenes from Medicago truncatula (MtPSY3) and Solanum lycopersicum (SlPSY3) strongly expressed exclusively upon root interaction with symbiotic arbuscular mycorrhizal (AM) fungi and moderately in response to phosphate starvation. They belong to a widespread clade of conserved PSYs restricted to dicots (dPSY3) distinct from the Poaceae-PSY3s involved in ABA formation. An ancient origin of dPSY3s and a potential co-evolution with the AM symbiosis is discussed in the context of PSY evolution. Knockdown of MtPSY3 in hairy roots of M. truncatula strongly reduced SL and AM-induced C13 α-ionol/C14 mycorradicin apocarotenoids. Inhibition of the reaction subsequent to phytoene synthesis revealed strongly elevated levels of phytoene indicating induced flux through the carotenoid pathway in roots upon mycorrhization. dPSY3 isogenes are coregulated with upstream isogenes and downstream carotenoid cleavage steps toward SLs (D27, CCD7, CCD8) suggesting a combined carotenoid/apocarotenoid pathway, which provides “just in time”-delivery of precursors for apocarotenoid formation.

Geochemical studies of planetary accretion and evolution have invoked various degrees of collisional erosion to explain differences in bulk composition between planets and chondrites. Here we undertake a full, dynamical evaluation of 'crustal stripping' during accretion and its key geochemical consequences. We present smoothed particle hydrodynamics simulations of collisions between differentiated rocky planetesimals and planetary embryos. We find that the crust is preferentially lost relative to the mantle during impacts, and we have developed a scaling law that approximates the mass of crust that remains in the largest remnant. Using this scaling law and a recent set of N-body simulations, we have estimated the maximum effect of crustal stripping on incompatible element abundances during the accretion of planetary embryos. We find that on average one third of the initial crust is stripped from embryos as they accrete, which leads to a reduction of ~20% in the budgets of the heat producing elements if the stripped crust does not reaccrete. Erosion of crusts can lead to non-chondritic ratios of incompatible elements, but the magnitude of this effect depends sensitively on the details of the crust-forming melting process. The Lu/Hf system is fractionated for a wide range of crustal formation scenarios. Using eucrites (the products of planetesimal silicate melting, thought to represent the crust of Vesta) as a guide to the Lu/Hf of planetesimal crust partially lost during accretion, we predict the Earth could evolve to a superchondritic 176-Hf/177-Hf (3-5 parts per ten thousand) at present day. Such values are in keeping with compositional estimates of the bulk Earth. Stripping of planetary crusts during accretion can lead to detectable changes in bulk composition of lithophile elements, but the fractionation is relatively subtle, and sensitive to the efficiency of reaccretion., 15 pages, 9 figures. Accepted for publication in EPSL. Abstract shortened. Accompanying animations can be found at http://www.star.bris.ac.uk/pcarter/crust_strip/

5,10,15,20-Tetrakis(4-aminophenyl)porphyrin (TAPP) undergoes oxidative polymerization to form electronically conductive, nanofibrous structures in which the porphyrin units are linked by phenazine bridges. Polymerizations by chemical oxidation, electrochemical oxidation, and interfacial oxidative polymerization are described. Poly-TAPP (pTAPP) films have been characterized using scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and UV–vis spectroscopy. The polymer morphology is consistently nanofibrous, with some differences depending on the specific synthetic method. The polymer films show distinctive electrochromism at different redox and protonation states. A Pourbaix diagram correlates the proposed redox and protonation states of the polymer with applied potential, pH, and perceived color of the film. pTAPP shows the lowest resistance to oxidative doping/dedoping at low pH and potentials between +0.4 and +0.5 V vs Ag/AgCl.

The versatility of porphyrins as optoelectronic or catalytic units makes them attractive elements for inclusion in functional materials. Polymers that include porphyrins have been created with a wide variety of structures and used in a wide range of applications.Thisreviewcoversrecentdevelopmentsinthesynthesis,characterizationandapplicationsofpolymericmaterials in which porphyrins are key components of the repeat units, including the rapidly growing area of metal‐organic frameworks and related covalent organic frameworks. ©2 015 Society of Chemical Industry

Various cleavage products of C40 carotenoid substrates are formed preferentially or exclusively in roots. Such apocarotenoid signaling or regulatory compounds differentially induced in roots during environmental stress responses including root colonization by arbuscular mycorrhizal fungi include ABA, strigolactones and C13 α-ionol/C14 mycorradicin derivatives. The low carotenoid levels in roots raise the question of whether there is a regulated precursor supply channeled into apocarotenoid formation distinct from default carotenoid pathways. This review describes root-specific isogene components of carotenoid pathways toward apocarotenoid formation, highlighting a new PSY3 class of phytoene synthase genes in dicots. It is clearly distinct from the monocot PSY3 class co-regulated with ABA formation. At least two members of the exclusive dicot PSY3s are regulated by nutrient stress and mycorrhization. This newly recognized dicot PSY3 (dPSY3 vs. mPSY3 from monocots) class probably represents an ancestral branch in the evolution of the plant phytoene synthase family. The evolutionary history of PSY genes is compared with the evolution of MEP pathway isogenes encoding 1-deoxy-d-xylulose 5-phosphate synthases (DXS), particularly DXS2, which is co-regulated with dPSY3s in mycorrhizal roots. Such stress-inducible isoforms for rate-limiting steps in root carotenogenesis might be components of multi-enzyme complexes committed to apocarotenoid rather than to carotenoid formation.

Apocarotenoids are a class of compounds that play important roles in nature. In recent years, a prominent role for these compounds in arbuscular mycorrhizal (AM) symbiosis has been shown. They are derived from carotenoids by the action of the carotenoid cleavage dioxygenase (CCD) enzyme family. In the present study, using tomato as a model, the spatio-temporal expression pattern of the CCD genes during AM symbiosis establishment and functioning was investigated. In addition, the levels of the apocarotenoids strigolactones (SLs), C13 α-ionol and C14 mycorradicin (C13/C14) derivatives were analyzed. The results suggest an increase in SLs promoted by the presence of the AM fungus at the early stages of the interaction, which correlated with an induction of the SL biosynthesis gene SlCCD7. At later stages, induction of SlCCD7 and SlCCD1 expression in arbusculated cells promoted the production of C13/C14 apocarotenoid derivatives. We show here that the biosynthesis of apocarotenoids during AM symbiosis is finely regulated throughout the entire process at the gene expression level, and that CCD7 constitutes a key player in this regulation. Once the symbiosis is established, apocarotenoid flux would be turned towards the production of C13/C14 derivatives, thus reducing SL biosynthesis and maintaining a functional symbiosis.

The singlet exciton diffusion properties of solution-cast thin films prepared from mixed substituent monoiodophenyl or monobromophenyl derivatives of 5,10,15,20-tetrakis(4-carbomethoxyphenyl)porphyrin (TCM4PP) were investigated for use in solar energy conversion applications. The photoluminescent singlet decay lifetime PL(t) of pristine porphyrin films and films lightly doped (0.1–0.6% wt) with [6,6]-phenyl-C61-butryic acid methyl ester (PCBM) were used to obtain relative quenching efficiencies (Q). The exciton diffusion coefficient (D) and exciton diffusion length (LD) for each derivative were obtained by modeling the quenching efficiency and PL lifetime decay data using a 3D exciton Monte Carlo diffusion simulation. Although the three TCMPP derivatives showed nearly identical absorbances and electrochemical properties, the monobromophenyl or monoiodophenyl substituted porphyrins exhibited significantly lower steady-state emission intensities and fluorescent lifetimes in solution. Amorphous thin films of the halogenated derivatives also exhibited a decrease in the PL decay lifetimes, relative quenching efficiencies, and reduced singlet exciton diffusion lengths. The singlet exciton diffusion length for TCM4PP was calculated to be 15 nm and decreased by 71% to 4.4 nm for TCM3IPP with the addition of a single iodo substituent. Photocurrent–voltage measurements of the derivatives in a PCBM bulk heterojunction device suggest that lowered exciton diffusion and enhanced singlet to triplet exciton conversion, due to the heavy atom effect, decreases photoconversion efficiency.

Maxillary obturator prostheses with hollow metal obturators can be made of titanium to reduce weight. To prevent perforation of the hollow obturator during modifications, the obturator is slightly undersized and covered with a replaceable cap. This cap is made of a soft copolymer to facilitate uncomplicated modifications in the resection area and to improve function.

It has long been recognized that Earth and other differentiated planetary bodies are chemically fractionated compared to primitive, chondritic meteorites and, by inference, the primordial disk from which they formed. However, it is not known whether the notable volatile depletions of planetary bodies are a consequence of accretion1 or inherited from prior nebular fractionation2. The isotopic compositions of the main constituents of planetary bodies can contribute to this debate3, 4, 5, 6. Here we develop an analytical approach that corrects a major cause of measurement inaccuracy inherent in conventional methods, and show that all differentiated bodies have isotopically heavier magnesium compositions than chondritic meteorites. We argue that possible magnesium isotope fractionation during condensation of the solar nebula, core formation and silicate differentiation cannot explain these observations. However, isotopic fractionation between liquid and vapour, followed by vapour escape during accretionary growth of planetesimals, generates appropriate residual compositions. Our modelling implies that the isotopic compositions of magnesium, silicon and iron, and the relative abundances of the major elements of Earth and other planetary bodies, are a natural consequence of substantial (about 40 per cent by mass) vapour loss from growing planetesimals by this mechanism.

The atomic-scale structure of aerodynamically levitated and laser-heated liquid tricalcium aluminate (${\mathrm{Ca}}_{3}{\mathrm{Al}}_{2}{\mathrm{O}}_{6}$) was measured at 2073(30) K by using the method of neutron diffraction with Ca isotope substitution (NDIS). The results enable the detailed resolution of the local coordination environment around calcium and aluminum atoms, including the direct determination of the liquid partial structure factor, ${S}_{\mathrm{CaCa}}(Q)$, and partial pair distribution function, ${g}_{\mathrm{CaCa}}(r)$. Molecular dynamics (MD) simulation and reverse Monte Carlo (RMC) refinement methods were employed to obtain a detailed atomistic model of the liquid structure. The composition ${\mathrm{Ca}}_{3}{\mathrm{Al}}_{2}{\mathrm{O}}_{6}$ lies at the CaO-rich limit of the CaO:${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ glass-forming system. Our results show that, although significantly depolymerized, liquid ${\mathrm{Ca}}_{3}{\mathrm{Al}}_{2}{\mathrm{O}}_{6}$ is largely composed of ${\mathrm{AlO}}_{4}$ tetrahedra forming an infinite network with a slightly higher fraction of bridging oxygen atoms than expected for the composition. Calcium-centered polyhedra exhibit a wide distribution of four- to sevenfold coordinated sites, with higher coordinated calcium preferentially bonding to bridging oxygens. Analysis of the MD configuration reveals the presence of $\ensuremath{\sim}10\phantom{\rule{0.16em}{0ex}}%$ unconnected ${\mathrm{AlO}}_{4}$ monomers and ${\mathrm{Al}}_{2}{\mathrm{O}}_{7}$ dimers in the liquid. As the CaO concentration increases, the number of these isolated units increases, such that the upper value for the glass-forming composition of CaO:${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ liquids could be described in terms of a percolation threshold at which the glass can no longer support the formation of an infinitely connected ${\mathrm{AlO}}_{4}$ network.

Pressure-temperature melting curves in two carbonate-bearing systems of relevance to Earth’s mantle have been determined using the laser-heated diamond-anvil cell (LH-DAC). The solidus along the MgSiO3-MgCO3 join in the MgO-SiO2-CO2 system (MS-CO2) was defined from 15 to 80 GPa using in situ melting criteria, reaching a maximum temperature of ~2340 K at 80 GPa. The occurrence of melting has been confirmed with ex-situ textural and chemical analysis of recovered samples. The melting curve has a negative d T /d P slope at pressures between ~15 and 23 GPa resulting from the subsolidus phase transition of ilmenite- to perovskite-structured MgSiO3. The shallow slope of the melting curve at pressures higher than this transition indicate that for plausible mantle geotherms carbonate-bearing silicate lithologies will melt throughout the lower mantle. The solidus of a mixture along the MgCO3-CaCO3 join was determined as a proxy for alkali-free carbonate lithologies. Melting temperatures increase from 1860 K at 16 GPa to ~2100 K above 35 GPa, where the melting curve flattens. The melting reaction magnesite + post-aragonite (high-pressure CaCO3) = melt was confirmed using an in situ experiment. We conclude that crystalline Mg and Ca carbonate mixtures are unstable with respect to molten carbonate at conditions of the convective lower mantle. The flat melting curves at high pressures in both systems suggests that subducted carbonates will undergo melting at lower mantle conditions, a process that may be important for superdeep diamond formation and carbon storage in the deep mantle.

The electronic and photovoltaic properties of junctions between the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and Si(111) surfaces have been investigated for a range of doping types, doping levels, and surface functionalization of the Si. PEDOT–poly(styrenesulfonate) (PSS) formed ohmic, low resistance contacts to H-terminated and CH_3-terminated p-type Si(111) surfaces. In contrast, PEDOT formed high barrier height (0.8–1.0 V) contacts to n-Si(111) surfaces, with CH_3-terminated n-Si(111)/PEDOT contacts showing slightly higher barrier heights (1.01 eV) than H-terminated n-Si(111)/PEDOT contacts (0.89 V). PEDOT contacts to CH_3-terminated and H-terminated n-Si(111) surfaces both produced photovoltages under illumination in accord with the Shockley diode limit based on bulk/recombination diffusion in the semiconductor. Such devices produced solar energy-conversion efficiencies of 5.7% under 100 mW cm^(–2) of simulated air mass 1.5 illumination. The electrical properties of PEDOT contacts to CH_3-terminated Si surfaces were significantly more stable in an air ambient than the electrical properties of PEDOT contacts to H-terminated Si surfaces. PEDOT films produced a low resistance, tunnel-barrier type of ohmic contact to n^+-Si(111) surfaces. Hence, through various combinations of doping type, doping level, and surface functionalization, the PEDOT/Si contact system offers a wide range of opportunities for integration into monolithic photovoltaic and/or artificial photosynthetic systems.

Unraveling the conditions at which Earth's metallic iron core formed yields important information about Earth's early accretion and differentiation history. Multi-variable statistical modeling of siderophile element partitioning between core-forming metallic liquids and silicate melts form the basis for physical models of core formation. While it seems clear that core segregation in a deep peridotitic magma ocean is generally consistent with many mantle siderophile element abundances, there is considerable disparity among extant physical models in terms of the key parameters of pressure, temperature and oxygen fugacity at which the core formed. Moreover, there is ongoing debate over whether simple single-stage equilibrium or more complex multi-stage accretion models are required by the partitioning data. Here we consider how variations in the statistical regression of partitioning data affect the outcomes of physical models for core formation. Taking extant experimental data sets for four well-studied siderophile elements (Ni, Co, W and V) as examples, we find that the regression model exerts a fundamental control on physical model outcomes. Further, the experimental data are currently too imprecise to discriminate among various single-stage and continuous core formation scenarios. Progress in the development of physical models requires better isolation of the independent variables that affect partition coefficients and verification of activity models at high pressure and temperature in order to reduce the global uncertainty in multi-variable statistical models.

This article describes an alternative technique for the fabrication of interim restorations. A thermoplastic, vacuum-formed template and translucent vinyl polysiloxane material are combined in the waxed diagnostic cast to fabricate a matrix in which the interim material can be placed. With this matrix, a variety of materials, such as dual-polymerized or light-polymerized resins, can be used in a predictable way. The major advantage of this technique is that it allows for the fabrication of accurate restorations with excellent reproduction of surface anatomy and for alterations of the tooth shape with light-polymerized materials.

The effects of peripheral alkyl groups and thermal annealing on the exciton quenching efficiency in bilayer porphyrinfullerene thin films has been investigated. The thin film UV-vis absorbance spectra, steady-state fluorescence emission, and thermal properties of three carboalkoxyphenyl porphyrin derivatives have been studied: tetra(4-carbohexoxyphenyl)porphyrin (TCH 4 PP), tetra(4-carbo-2-ethylhexoxyphenyl)porphyrin (TCEH 4 PP), and tetra(4-carbooctoxyphenyl)-porphyrin (TCO 4 PP). The quenching efficiencies of these three derivatives have been calculated from their steady-state emission using pristine spin cast films and films with an evaporated C 60 bilayer. Structural analyses have been performed using X-ray diffraction (XRD), UV-vis spectroscopy, and thermal properties were studied using differential scanning calorimetry measurements (DSC). Annealing the films caused significant structural changes as was observed in the UV-vis absorbance spectra and XRD diffraction patterns. Prior to thermal annealing, quenching efficiencies are greatest for the TCH 4 PP and TCO 4 PP (hexyl and octyl derivatives), which is in agreement with previous bulk quenching experiments to calculate exciton diffusion lengths. 1 After annealing, the hexyl derivative (TCH 4 PP) showed the lowest bilayer quenching efficiency and indicated evidence of significant molecular rearrangements.

Jeffbenite, ideally Mg3Al2Si3O8, previously known as tetragonal-almandine-pyrope-phase ('TAPP’), has been characterized as a new mineral from an inclusion in an alluvial diamond from São Luiz river, Juina district of Mato Grosso, Brazil. Its density is 3.576 g/cm3 and its microhardness is ∼7. Jeffbenite is uniaxial (-) with refractive indexes ω = 1.733(5) and ε = 1.721 (5). The crystals are in general transparent emerald green.Its approximate chemical formula is (Mg262Fe2+0.27)(Al186Cr016)(Si2 g2Al018)O12 with very minor amounts of Mn, Na and Ca. Laser ablation ICP-MS showed that jeffbenite has a very low concentration of trace elements. Jeffbenite is tetragonal with space group I42d, cell edges being a = 6.5231(1) and c = 18.1756(3) Å. The main diffraction lines of the powder diagram are [d (in Å), intensity, hkl]: 2.647, 100, 2 0 4; 1.625, 44, 3 2 5; 2.881, 24, 2 1 1; 2.220, 19, 2 0 6; 1.390, 13, 4 2 4; 3.069, 11,2 0 2; 2.056, 11,2 2 4; 1.372, 11,2 0 12.The structural formula of jeffbenite can be written as (M1)(M2)2(M3)2(T1)(T2)2O12 with M1 dominated by Mg, M2 dominated by Al, M3 dominated again by Mg and both T1 and T2 almost fully occupied by Si. The two tetrahedra do not share any oxygen with each other (i.e. jeffbenite is classified as an orthosilicate).Jeffbenite was approved as a new mineral by the IMA Commission on New Minerals and Mineral Names with the code IMA 2014-097. Its name is after Jeffrey W. Harris and Ben Harte, two world-leading scientists in diamond research. The petrological importance of jeffbenite is related to its very deep origin, which may allow its use as a pressure marker for detecting super-deep diamonds. Previous experimental work carried out on a Ti-rich jeffbenite establishes that it can be formed at 13 GPa and 1700 K as maximum P-T conditions.

The electrical properties of individual p- and n-type silicon microwires have been investigated using a direct contact formation technique, in which an Ohmic contact between the tungsten probe and microwire was produced by applying mechanical force to the probe/microwire junction. This method alleviated the need for lithography or a high-temperature process to form a metal/Si ohmic contact. The technique was also used to characterize the Si microwire/conducting polymer junctions in a single cell of a membrane-supported bilayer Si microwire structure that is of interest for the direct production of fuels from sunlight. The data indicate that the combination of PEDOT–PSS–Nafion and highly doped Si microwires is suitable, from an electrical resistance perspective, to be used in a solar fuels generation device.

The electrical (DC) behavior of single silicon microwires has been determined by the use of tungsten probes to make ohmic contact to the silicon microwires. The basic electrical properties of the microwires, such as their DC resistivity and the doping distribution along the length of the microwires, were investigated using this approach. The technique was also used to characterize the junction between silicon microwires and conducting polymers to assess the suitability of such contacts for use in a proposed artificial photosynthesis system.

Arrays of B-doped p-Si microwires, diffusion-doped with P to form a radial n+ emitter and subsequently coated with a 1.5-nm-thick discontinuous film of evaporated Pt, were used as photocathodes for H_2 evolution from water. These electrodes yielded thermodynamically based energy-conversion efficiencies >5% under 1 sun solar simulation, despite absorbing less than 50% of the above-band-gap incident photons. Analogous p-Si wire-array electrodes yielded efficiencies

This review summarizes recent advances in the use of porphyrins, phthalocyanines, and related compounds as components of solar cells, including organic molecular solar cells, polymer cells, anddye-sensitized solar cells. The recent report of a porphyrin dye that achieves 11% power conversion efficiency in a dye-sensitized solar cell indicates that these classes of compounds can be as efficient as the more commonly used ruthenium bipyridyl derivatives.

Purpose This study examines the effect of FOXC1 on the prostaglandin pathway in order to explore FOXC1's role in the prostaglandin-resistant glaucoma phenotype commonly seen in Axenfeld-Rieger syndrome. Methods Binding and transcriptional activity of FOXC1 to the gene coding for the EP3 prostaglandin receptor (PTGER3) were evaluated through ChIP-qPCR and luciferase-based assays. Immortalized trabecular meshwork cells (TM1) and HeLa cells had FOXC1 mRNA reduced via siRNA interference. qPCR and Western blot experiments were conducted to examine the changes in prostaglandin receptor expression brought about by lowered FOXC1. TM1 cells were then treated with 10 μM latanoprost acid and/or an siRNA for FOXC1. The expression of fibronectin and matrix metalloproteinase 9 were evaluated via qPCR in each treatment condition. Results ChIP-qPCR and luciferase experiments confirmed that FOXC1 binds to and activates transcription of the EP3 gene prostaglandin receptor. qPCR and Western experiments in HeLa and TM1 cells showed that FOXC1 siRNA knockdown results in significantly lowered EP3 levels (protein and RNA). In addition, RNA levels of the other prostaglandin receptor genes EP1 (PTGER1), EP2 (PTGER2), EP4 (PTGER4), and FP (PTGFR) were altered when FOXC1 was knocked down in TM1 and HeLa cells. Analysis of fibronectin expression in TM1 cells after treatment with 10 μM latanoprost acid showed a statistically significant increase in expression; this increase was abrogated by cotreatment with a siRNA for FOXC1. Conclusions We show the abrogation of latanoprost signalling when FOXC1 is knocked down via siRNA in a trabecular meshwork cell line. We propose that the lower levels of active FOXC1 in Axenfeld-Rieger syndrome patients with glaucoma account for the lack of response to prostaglandin-based medications.