Standard Molar Volumes and Heat Capacities of Aqueous Solutions of Trifluoromethanesulfonic Acid at Temperatures up to 573 K and Pressures to 30 MPa

Densities and heat capacities of dilute aqueous solutions (0.025 to 0.4 mol⋅kg⁻¹) of trifluoromethanesulfonic acid (triflic acid) were measured with original high-temperature, high-pressure instruments at temperatures and pressures up to 574 K and 31 MPa, respectively. Standard molar volumes and standard molar heat capacities were obtained via extrapolation of the apparent molar properties to infinite dilution. The evolution of these standard derivative properties of triflic acid with temperature and pressure is qualitatively compared with that of other acids of different strengths.     

Chemical Kinetic Strategies for High‐Throughput Screening of Protein Aggregation Modulators

Insoluble aggregates staining positive to amyloid dyes are known histological hallmarks of different neurodegenerative disorders and of type II diabetes. Soluble oligomers are smaller assemblies whose formation prior to or concomitant with amyloid deposition has been associated to the processes of disease propagation and cell death. While the pathogenic mechanisms are complex and differ from disease to disease, both types of aggregates are important biological targets subject to intense investigation in academia and industry. Here we review recent advances in the fundamental understanding of protein aggregation that can be used on the development of anti‐amyloid and anti‐oligomerization drugs. Specifically, we pinpoint the chemical kinetic aspects that should be attended during the development of high‐throughput screening assays and in the hit validation phase. The strategies here devised are expected to establish a connection between basic research and pharmaceutical innovation.     

Reactions induced by 35 MeV 6He beam on 12C and 14C

The ⁶He+^12,14C scattering and reactions have been studied using a 35 MeV ⁶He radioactive beam and preliminary results are presented. The three-body reaction ⁶He+¹²C ↦ ¹⁰Be+2 α has been clearly identified and sequential decay of intermediate states in ¹⁴C has been studied. Search for an analog reaction on ¹⁴C, ⁶He+¹⁴C ↦ ¹²Be+2 α, has not given conclusive results yet. Other interesting reactions with this entrance channel are discussed.     

Quantum ratchets with few bands below the barrier

We investigate directed motion in nonadiabatically rocked ratchet systems sustaining few bands below the barrier. Upon restricting the dynamics to the lowest M bands, the total system-plus-bath Hamiltonian is mapped onto a discrete tight-binding model containing all the information both on the intrawell and interwell tunneling motion. A closed form for the current in the incoherent tunneling regime is obtained. In effective single-band ratchets, no current rectification occurs. We apply our theory to describe rectification effects in vortex quantum ratchets devices. Current reversals upon variation of the ac-field amplitude or frequency are predicted.     

A simple sensitive recording differential refractometer for column chromatography

Light passes through a hollow prism containing the sample liquid and is then focussed on a position-sensitive photodiode. Movement of the image due to a change in the refractive index of the sample produces an electrical signal which is recorded directly on a potentiometer recorder.     

Mass spectrometry of metal chelates-III Further studies on metal oxinates

The mass spectra of the oxmates of gallium, dysprosium, beryllium, samarium, cadmium, neodymium, indium, bismuth, lanthanum, yttrium and gadolinium have been recorded. The results have been correlated with the structures proposed m the literature. The integrated ion current method has been applied to determine submicrogram quantities of some of these compounds. Oxinates insoluble in organic solvents or undergoing reaction on solution were precipitated directly in the evaporation probe. The factors which determine the suitability of metal chelates for the estimation of metals by this method are discussed together with the instrumental factors which determine the ultimate sensitivity.     

Zero-field muon spin rotation in monocrystalline chromium

Spin precession of positive muons in chromium in zero applied magnetic field is reported for the first time. The observations cover the temperature range from about 2.5 K to 10 K and thus pertain to the so-called longitudinal spin-density wave (LSDW) state of antiferromagnetic Cr. The conclusions that may be drawn from the existence of one rather sharp spin precession line are discussed, among them the estimateD _μ=2.4·10⁻¹⁴ m² s⁻¹ for the muon diffusivity at 4 K. Considerable evidence exists for a strong interactions of μ⁺ with the charge-density waves that are likely to accompany the LSDWs in Cr.     

Adsorption of calcium and magnesium ions on surfaces

The adsorption of calcium and magnesium ions at trace levels in solution on borosilicate glass and polypropylene is described. The rate and extent of adsorption increases with increasing pH and the process is not completely reversible. The apparent energies of activation for the adsorption of calcium and magnesium ions on borosilicate glass are 17.5 and 10.5 kJ mol^?1, respectively. The corresponding half-lives are 568 and 127 h. For polypropylene the half-lives increase to 5775 and 537 h, respectively.     

Light scattering and self-focusing in laser produced sparks

The spectral and temporal behaviour of back-and forward-scattered laser light on laser produced spark are investigated. Short backscattered pulses from the plasma fronts appears just after the breakdown. Self-focusing caused by nonlinear heating begins when the plasma filament is already formed.     

Stark shift of methanol vibration levels measured by optoacoustic lamb dip spectroscopy

The Stark constant of methanol vibrational transitions (ν, n, τ, K, J): (0, 1, 2, 5, 9) and (0, 0, 1, 8, 16) → (1, 0, 1, 8, 16) is measured using the derivative optoacoustic Lamb dip spectroscopy method.