The electroactive integrated optical waveguide: ultrasensitive spectroelectrochemistry of submonolayer adsorbates

Highly sensitive spectroelectrochemistry of adsorbed films on ITO is demonstrated with the electroactive integrated optical waveguide (EA-IOW). The EA-IOW, a single-mode planar waveguide coated with an ITO layer, is ～10(4)-fold more sensitive to changes in absorbance occurring during electrochemical events versus a single-pass transmission spectroelectrochemical experiment, as demonstrated by reduction of surface-adsorbed methylene blue. Furthermore, the EA-IOW is selective to near-surface events, as it is relatively insensitive to absorbance by solutions of dissolved chromophores at <1 mM. The EA-IOW is also used to monitor the formation of Prussian Blue during the reduction of ferricyanide, an event that is not easily followed using current-detected cyclic voltammetry, due to interfering faradaic and non-faradaic electrochemical events. The optical background of the EA-IOW is potential-dependent and is explained by ion diffusion into the ITO and by voltage-dependent changes in optical constants for the material. Finally, the high sensitivity of the EA-IOW (relative to other evanescent-field-based spectroelectrochemical techniques) is discussed in terms of its design.     

Top-down MS of large proteins: a new record

Researchers bread a record by fragmenting proteins >200 kDa in a mass spectrometer with a top-down approach.     

Pheromone responsiveness is regulated by components of the Gpr1p‐mediated glucose sensing pathway in Saccharomyces cerevisiae

Many fungi have evolved mechanisms to assess environmental nutrient availability prior to the energy‐intensive process of mating. In this study, we examined one such system in Saccharomyces cerevisiae, involving a glucose‐sensing pathway mediated by Gpr1p and the pheromone‐induced mating pathway. Initially we observed that the mating pathway in MATa cells is sensitive to environmental glucose depletion. This phenomenon can be partially reversed with a high glucose spike, but not with the addition of low levels of glucose. Deletion of the low‐affinity glucose receptor, Gpr1p, eliminated this glucose‐induced recovery of pheromone responsiveness. We then determined the impact of GPR1 deletion on the mating pathway and observed that, in all end points studied, the mating pathway response to pheromone is reduced in the absence of Gpr1p. Similarly, elimination of the Gα for Gpr1p, Gpa2p, resulted in reduction in pheromone sensitivity in all assays studied. The negative effect of removing Gpr1p on mating pathway activation could be recovered by overexpressing the mating receptor, Ste2p. Furthermore, Ste2p levels are reduced in the absence of glucose and GPR1. These data suggest that activity of the GPCR‐mediated mating pathway in S. cerevisiae is modulated by extracellular glucose concentrations through the only other GPCR in MATa cells, Gpr1p. Copyright © 2014 John Wiley & Sons, Ltd.     

Electrochemical waste water treatment: Electrooxidation of acetaminophen

Oxidation of acetaminophen at boron-doped diamond (BDD) and at Ti/SnO₂ anodes in a plug-flow divided electrochemical reactor led to electrochemical combustion, whereas at Ti/IrO₂ benzoquinone was the exclusive product except at very long electrolysis times. The difference is explicable in terms of the different mechanisms of oxidation: direct oxidation at the anode for Ti/IrO₂ vs. indirect oxidation involving electrogenerated hydroxyl radicals at BDD and Ti/SnO₂. At BDD, at which the efficiency of degradation of acetaminophen was greatest, the rate of electrolysis at constant concentration was linearly dependent on the current, and at constant current linearly dependent on the concentration. Current efficiencies for mineralization up to 26% were achieved without optimization of the cell design.     

Extensive Ozonation of C60: Degradation or Polymerization?

The impact of the oxidizing agent ozone (O₃) on the structure of the most common spherical allotrope of carbon, buckminsterfullerene (C₆₀) is studied. Past studies measured ozonation of C₆₀ over short periods of time. In this study, we establish that C₆₀ is completely degraded, not polymerized, during ozonation. The techniques, laser desorption time-of-flight mass spectrometry, UV/Vis absorbance spectroscopy, and FT-Raman are used to study the molecular degradation of the spherical allotrope C₆₀ by O₃.     

Identifying pathways of exposure to highway pollutants in great crested newt (Triturus cristatus) road mitigation tunnels

Road mitigation tunnels are increasingly deployed for amphibians but very little is known about chemical pollution in such schemes. We assessed pollution pressures associated with road runoff at a major great crested newt mitigation scheme in England. Sediments and waters in the mitigation system were analysed for major physico‐chemical parameters, trace metals and total petroleum hydrocarbons and compared to a nearby reference site. Seven out of eight tested metals including copper, zinc, lead and iron were in significantly greater concentrations in the tunnels than at a reference site and at environmentally significant concentrations. Water samples also exhibited elevated concentrations of aluminium and chromium and occasionally extreme alkaline pH associated with leaching of portlandite in tunnel cements. High conductivity values in waters and sediments corresponding with seasonal de‐icing salt application were also apparent. The study highlights the potential pollutant pressures for amphibians associated with large‐scale urban development and road mitigation schemes.     

Multiple myeloma with monoclonal surface immunoglobulin expression: a case report

BACKGROUND: Plasma cells from patients with multiple myeloma have been found to express the immunophenotype of normal plasma cells without surface immunoglobulin expression. CASE: A case occurred of multiple myeloma with monoclonal surface immunoglobulin expression, defined by morphology and flow cytometric immunophenotyping of a fine needle aspiration biopsy of an osteolytic rib lesion and a bone marrow aspirate as well as urine and serum protein electrophoresis with immunofixation. CONCLUSION: The clinical significance of monoclonal surface immunoglobulin expression in rare cases of multiple myeloma is uncertain, and other parameters with clinical significance (CD10 positivity, multiple myeloid antigen expression) will continue to be more useful until additional cases accrue.     

Hypnotic underestimation of time: The busy beaver hypothesis.

Two experiments tested the hypothesis that the hypnotic underestimation of time is mediated by attentional processing. In Exp 1, variations in the demands placed on attentional resources produced substantial differences in the subjective estimates of identical length intervals occurring within a hypnotic context. ln Exp 2, attentional manipulation was assessed in both hypnotic and waking contexts. Time judgments were again found to vary with attentional demands but not with hypnotic context. The results are consistent with a busy beaver hypothesis, which holds that hypnotic, as well as nonhypnotic, time estimates are a by-product of the attentional processing demands of the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of surface potential on aggregation and transport of titania nanoparticles

To investigate the effect of pH on nanoparticle aggregation and transport in porous media, we quantified nanoparticle transport in two-dimensional structures. Titania was used as a model compound to explore the effects of surface potential on particle mobility in the subsurface. Results show that pH, and therefore, surface potential and aggregate size, dominate nanoparticle interactions with each other and surfaces. In each solution, nanoparticle aggregate size distributions were bimodal or trimodal, and aggregate sizes increased as the pH approached the pH of the point of zero charge (pHzpc). Over 80% of suspended particles and aggregates were mobile over the pH range of 1-12, except close to the pHzpc of the surfaces, where the particles are highly aggregated. The effect of pH on transport is not symmetric around the pHzpc of the particles due to charging of the channel surfaces. However, transport speed of nanoparticle aggregates did not vary with pH. The surface element integration technique, which takes into account the effect of curvature of particles on interaction energy, was used to evaluate the ability of theory to predict nanoparticle transport.