Arsenic concentrations and distribution in Chautauqua Lake sediments

In order to describe the occurrence and to investigate the sources of arsenic found in Chautauqua Lake sediments, 98 grab samples have been analyzed by neutron activation analysis. The arsenic concentrations were found to range from <0.5 to 58.75 ppm for 96 of the 98 samples with an overall average value of 22.10 ppm. The two other samples had concentrations of 140.0 and 306.0 ppm. High arsenic concentrations have been positively correlated with a decrease in the sediment particle size. Natural arsenic concentrations found in the soil and bedrock in the area do not explaint the observed concentrations in the lake sediment. The increase in arsenic appears to be related to the spraying of sodium arsenite as an aquatic pesticide during the period 1955–1963.     

New perspectives in the studies of resonance scattering

We consider various possibilities for studies of nuclear structure in resonance reactions induced by radioactive beam. We discuss investigations on both sides of nuclear stability as well as studies of the α-cluster structure of light nuclei applying the reverse geometry thick target method.     

Self-Assembly of a Redox Active,Metallosupramolecular [Pd3L6]6+ Complex Using a Rotationally Flexible Ferrocene Ligand

A new ferrocene-containing [Pd₃( L_4EFc )₆]⁶⁺(X⁻)₆ ( C ⋅ BF₄ and C ⋅ SbF₆ where X=BF₄⁻ or SbF₆⁻) self-assembled double-walled triangle has been synthesized from the known, rotationally flexible, 1,1′-bis(4-pyridylethynyl)ferrocene ligand ( L_4EFc ), and characterized by ¹H, ¹³C and diffusion ordered (DOSY) NMR spectroscopies, high-resolution electrospray ionization mass spectrometry (HR−ESI−MS), X-ray crystallography and cyclic voltammetry (CV). The molecular structures confirmed that double-walled triangle cage systems ( C ⋅ BF₄ and C ⋅ SbF₆ ) were generated. C ⋅ BF₄ was shown to interact with the anionic guest, p-toluenesulfonate. CV experiments revealed that the triangles were redox active, however addition of the guest did not influence the redox potentials.     

Microscale Crystals of Cytochrome c and Calixarene on Electrodes: Interprotein Electron Transfer between Defined Sites

The assembly of redox proteins on electrodes is an important step in biosensor development. Recently, p‐sulfonato‐calix[4]arene was shown to act as “molecular glue” for the assembly and crystallization of cytochrome c (cyt c). Electrochemical data are presented for microscale cyt c–calixarene crystals grown on self‐assembled monolayers (SAM)‐modified Au electrodes. The crystals were characterized by cyclic voltammetry and exceptionally high concentrations of electroactive cyt c were obtained. The peak currents were found to increase linearly with the square root of the scan rate, thus allowing an evaluation of the rate constant for electron self‐exchange. This study revealed high electroactivity accompanied by fast interprotein electron transfer in crystals, which may have implications for the construction of novel bioelectronic devices.     

Electron spectroscopy using excited atoms and photons; VIII penning ionization of the hydrogen halides

Electron spectra resulting from collisions of thermal 2³S metastable helium atoms with HF, HCl, HBr and HI are compared with the respective 584     

Autocrosslinkable methyl-2-phenylethylpolysiloxane stationary phase for capillary column gas chromatography

Methyl-2-phenylethylpolysiloxane polymers have been synthesized for comparison with methylphenylpolysiloxane stationary phases for gas chromatography. The 50% 2-phenylethyl polysiloxane was found to be autocrosslinkable at 260°C without addition of free redical initiator. Although the selectivity of this phase appears to be similar to the 50% phenyl polysiloxane, its thermal stability is not as high.