Proton Conductivities of Graphene Oxide Nanosheets: Single,Multilayer, and Modified Nanosheets

Proton conductivities of layered solid electrolytes can be improved by minimizing strain along the conduction path. It is shown that the conductivities (σ) of multilayer graphene oxide (GO) films (assembled by the drop‐cast method) are larger than those of single‐layer GO (prepared by either the drop‐cast or the Langmuir‐Blodgett (LB) method). At 60 % relative humidity (RH), the σ value increases from 1×10⁻⁶ S cm⁻¹ in single‐layer GO to 1×10⁻⁴ and 4×10⁻⁴ S cm⁻¹ for 60 and 200 nm thick multilayer films, respectively. A sudden decrease in conductivity was observed for with ethylenediamine (EDA) modified GO (enGO), which is due to the blocking of epoxy groups. This experiment confirmed that the epoxide groups are the major contributor to the efficient proton transport. Because of a gradual improvement of the conduction path and an increase in the water content, σ values increase with the thickness of the multilayer films. The reported methods might be applicable to the optimization of the proton conductivity in other layered solid electrolytes.     

Whole-body counter surveys of over 2700 babies and small children in and around Fukushima Prefecture 33 to 49 months after the Fukushima Daiichi NPP accident

BABYSCAN, a whole-body counter (WBC) for small children was developed in 2013, and units have been installed at three hospitals in Fukushima Prefecture. Between December, 2013 and March, 2015, 2707 children between the ages of 0 and 11 have been scanned, and none had detectable levels of radioactive cesium. The minimum detectable activities (MDAs) for ¹³⁷Cs were ≤3.5 Bq kg⁻¹ for ages 0–1, decreasing to ≤2 Bq kg⁻¹ for ages 10–11. Including the ¹³⁴Cs contribution, these translate to a maximum committed effective dose of ∼16 µSv y⁻¹ even for newborn babies, and therefore the internal exposure risks can be considered negligibly small.Analysis of the questionnaire filled out by the parents of the scanned children regarding their families’ food and water consumption revealed that the majority of children residing in the town of Miharu regularly consume local or home-grown rice and vegetables, while in Minamisoma, a majority avoid tap water and produce from Fukushima. The data show, however, no correlation between consumption of locally produced food and water and the children’s body burdens.     

The heat capacity of the doubly reentrant mesogen: 4-cyanobenzoyloxy-4′-octylbenzoyloxy-p-phenylene

Abstract

Heat capacity of a 20 g sample of the mesogen 4-cyanobenzoyloxy-4′-octylbenzoyloxy-p-phenylene was measured in the temperature range 380 to 510 K by adiabatic calorimetry. The C _p versus T data is interpreted in terms of thermodynamically equivalent S_A1 and S_Ad phases whose Gibbs potential surface intersects the thermodynamically equivalent reentrant nematic and nematic Gibbs potential surface in such a way as to define the first order doubly reentrant phase sequence: S_A1-N-S_Ad-N. The data do not allow any precise estimates of transition enthalpies.     

Long-term behavior of 137Cs and 3H activities from TEPCO Fukushima NPP1 accident in the coastal region off Fukushima,Japan

Journal of Radioanalytical and Nuclear Chemistry - Decreasing trends of both 137Cs and 3H activity concentrations and an increasing trend of 3H/137Cs activity ratio at Fukushima Dai-ichi Nuclear...     

Precise Proton Mapping near Ionic Micellar Membranes with Fluorescent Photoinduced-Electron-Transfer Sensors

One of the challenges for fluorescent sensors is to reduce their target environment size from a micrometer scale, such as biological cells, to a nanometer scale. Proton maps near membranes are of importance in bioenergetics and are the first goal in nanometer-scale analysis with fluorescent sensors. Thirty-three fluorescent photoinduced-electron-transfer pH sensors bearing an environment-sensitive benzofurazan fluorophore and having different hydrophobicity/hydrophilicity and hydrogen-bonding abilities were prepared. These sensors were scattered in nanospaces associated with anionic and cationic micelles as model membranes to indicate proton availability and polarity in local spaces. Gathering the data from the sensors allowed the successful drawing of proton maps near anionic and cationic micelles, in which electrostatic attraction/repulsion of protons by the charged head groups of micelles and dielectric suppression of protons were clearly observed.     

Intrinsic interaction mode of an inhalation anesthetic with globular proteins: a comparative study on ligand recognition

Interaction mode of an inhalation anesthetic halothane with water-soluble globular proteins, myoglobin (Mgb) and lysozyme (Lys), was studied by differential scanning calorimetry (DSC) and viscometry, and the results were compared with those of bovine serum albumin (BSA). The anesthetic sensitivity was markedly different among the proteins: Mgb was destabilized, Lys was slightly destabilized, and BSA was conversely stabilized. Further, the interaction mode was quite different from those of specific binders for the proteins. The anesthetic sensitivity was highly correlated with the hydrophilicity on the protein surface (Mgb?<?Lys?<?BSA) and the rigidity of the protein structure (BSA????Mgb?<?Lys). We showed that the anesthetic sensitivity among globular proteins can be roughly classified into four categories, and proteins with small hydrophilicity and soft structure are suitable as model proteins of anesthesia. By contrast, the binding of the specific binders was characterized by the lower effective concentrations. The molar ratio of the binder to the protein at the effective concentration was well consistent with the binding number determined from the X-ray structural analysis. Moreover, the interaction mode of the binder was not necessarily in accord with the mode expected from the change in the protein structure. Considering the above facts, we can systematically interpret the effect of an anesthetic on globular proteins by four factors: (1) hydrophobicity of an anesthetic, (2) hydrophilicity of a protein surface, (3) rigidity of a protein structure, and (4) molar ratio of an anesthetic to a protein at the effective concentration.