Cosputtered Calcium Manganese Oxide Electrodes for Water Oxidation.

Calcium manganese oxide films were prepared by cosputter deposition from Mn and CaMnO targets and evaluated for their suitability as catalysts for the oxygen evolution reaction (OER). Scanning electron microscopy (SEM) revealed a compact morphology for the as-deposited films and the formation of nanorodlike features on the surfaces after annealing at 600 °C. X-ray-photoelectron-spectroscopy analysis showed that the surface oxidation state is close to +III (as in MnO) for the as-deposited films and increases slightly to a mixture of III and IV after annealing occurs in dry air at 400-600 °C.

Screen-printed calcium-birnessite electrodes for water oxidation at neutral pH and an "electrochemical harriman series".

A mild screen-printing method was developed to coat conductive oxide surfaces (here: fluorine-doped tin oxide) with micrometer-thick layers of presynthesized calcium manganese oxide (Ca-birnessite) particles. After optimization steps concerning the printing process and layer thickness, electrodes were obtained that could be used as corrosion-stable water-oxidizing anodes at pH 7 to yield current densities of 1 mA cm(-2) at an overpotential of less than 500 mV. Analyses of the electrode coatings of optimal thickness (≈10 μm) indicated that composition, oxide phase, and morphology of the synthetic Ca-birnessite particles were hardly affected by the screen-printing procedure.

Thermodynamic parameters of cooperative helix-to-coil transitions from synthetic A-U-rich oligoribonucleotides up to fourteen basepairs.

Heat induced helix-to-coil transitions are studied in the form of ultraviolet-hypochromicity profiles by absorbance spectroscopy, and delta Cp-curves by differential scanning calorimetry of self-complementary ribonucleotides. The results are analyzed and compared. Van 't Hoff transition enthalpies derived by UV-experiments incorporating concentration variations are found to differ from six-parameter and two-parameter Marquardt-fits on the melting profiles.

Thermodynamics of double- and triple-helical aggregates formed by self-complementary oligoribonucleotides of the type rAxUy.

The thermal denaturation of a series of oligoribonucleotides of the form rAxUy (x = 5 or 7 and y = 3-11) has been characterized by means of IR spectroscopy, UV spectroscopy, and DSC. IR spectra proved the occurrence of double- and triple-helical regions at various contents of uracil residues in the nucleotide. From DSC measurements transition enthalpies, entropies, and free enthalpies were derived.

Analysis of oligonucleotides by capillary gel electrophoresis.

Analysis of oligonucleotides with gel-filled capillary columns is a fast, efficient and automated way to check their purity. Gel-filled columns were optimized to separate oligonucleotides which were 20-50 nucleotides in length. The influence of sample size on resolution is discussed.

A thermodynamic study on rA7U7.

Ultraviolet absorbance spectroscopy and differential scanning calorimetry were employed to study the heat-induced helix-to-coil transition of the oligoribonucleotide rA7U7. The analysis of concentration-dependent ultraviolet 'melting' profiles was used to derive the van't Hoff transition enthalpy delta HUVvH (-458 kJ/mol cooperative unit). From the DSC data we calculated the calorimetric transition enthalpy delta Hcal (-412.

Near-heme histidine residues of deoxy- and oxymyoglobins.

Proton NMR titration curves of the histidine Cepsilon-H resonances of the deoxy and oxy forms of human, horse, and sperm whale myoglobins (Mb) were determined and compared with the results for the met and azide forms. One extra titrating resonance (H-8) was observed for each deoxy-Mb compared with the corresponding met-Mb, and a further extra resonance (H-9) was observed for the oxy-Mb form. These resonances correspond to the two additional resonances previously described for azide-Mb [Hayes, M.

Conformational studies on murein-lipoprotein from the outer membrane of Escherichia coli.

Conformational studies on an isolated integral membrane protein are reported. Lipoprotein of Escherichia coli outer membrane was released from murein by treatment with either lysozyme or trypsin. The isolated lysozyme-released lipoprotein (lipoprotein I) contained 2 or 3 muropeptides covalently linked at the C-terminal end, while the trypsin-released lipoprotein (lipoprotein II) was free of muropeptides and lacked the C-terminal peptide Tyr-Arg-Lys.

Amino acid sequence studies on the branched, synthetic polypeptide antigens of the immune response- 1 gene system.

Three immunogens with side chains of random amino acid sequence, poly (L Phe, l glu)-poly (DL Ala)--poly (L Lys) [(Phe, G)-A--L 223], poly (L Tyr, L Glu)-poly (DL Ala)--poly (L Lys) [(T, G)-A--L 509] and (T, G)-A-L 52, as well as two immunogens with side chains of defined amino acid sequences, GGT-A--L and TG-A--L, were sequenced using a Beckman automated sequenator. Despite the lack of a unique amino acid sequence for the amino terminus, reasonable results for the sequence studies were obtained using the Edman reaction. GGT-A--L and TG-A--L had 70% and 80% of their side chains respectively, with the desired sequence.

A variable region subclass of heavy chains common to immunoglobulins G, A, and M and characterized by an unblocked amino-terminal residue.

Heavy chains of IgG, IgA, and IgM classes of human immunoglobulins were compared by N-terminal residue determination and partial amino acid sequence analysis. A third subclass of the variable region of heavy chains was observed; an unblocked glutamic acid as the N-terminal residue is characteristic of this subclass. Our results indicated that the heavy chain variable region subclasses are not class specific, and that a given heavy chain variable region may be found in association with constant regions for mu-chains, alpha-chains, or gamma-chains of various subclasses.

Implications of heavy chain disease protein sequences for multiple gene theories of immunoglobulin synthesis.

The sequence of the amino-terminal 34 amino acids of gamma-heavy chain disease (gamma-HCD) protein Hi is homologous with the amino-terminal region of immunoglobulin heavy chains. gamma-heavy chain disease is smaller than a normal gamma-chain, but has the carboxy-terminal composition expected for gamma-chains and must, therefore, contain an internal deletion. Comparison of the Hi sequence with that of gamma-heavy chain disease Zu, which also has an internal deletion, indicates that the site of internal deletion is not a constant characteristic of gamma-heavy chain disease proteins.