Thermodynamics and kinetics of NAD+ adsorption on a glassy carbon electrode

Thermodynamics and kinetics of nicotinamide adenine dinucleotide (NAD⁺) adsorption on a glassy carbon (GC) electrode surface was investigated at various electrode potentials and NAD⁺ concentrations using differential capacitance (DC) and attenuated total reflection Fourier transform infrared (ATR-FTIR) techniques. Equilibrium adsorption measurements confirmed that NAD⁺ spontaneously and strongly adsorbs on the GC electrode surface. The affinity of NAD⁺ towards adsorption on the GC electrode surface was found to increase with an increase in electrode potential (charge) to more positive values; the corresponding apparent Gibbs free energy of adsorption was ?32.80?±?0.25, ?35.61?±?0.86, and ?38.02?±?0.40 kJ mol^?1 on negatively, neutral, and positively charged electrode surfaces, respectively. The kinetics of NAD⁺ adsorption is also found to be highly dependent on the electrode surface potential (charge), and it increases with an increase in electrode potential (charge) to positive values. The adsorption process was modeled using a two-step kinetic model, in which the adsorption process involves the formation of two forms of NAD⁺ on the surface: the thermodynamically unstable (NAD⁺ _ads,rev) and stable (NAD⁺ _ads,stable) forms. ATR-FTIR further confirmed that NAD⁺, indeed, adsorbed on the GC electrode surface.     

Polynomial bounds for Large Bernoulli sections of ℓ 1 N

We present a quantitative form of the result of Bai and Yin from [2], and use to show that the section of ℓ ₁ ^(1+δ)n spanned byn random independent sign vectors is with high probability isomorphic to euclidean with isomorphism constant polynomial in δ⁻¹. Partially supported by BSF grant 2002-006. Supported by the National Science Foundation under agreement No. DMS-0111298. Supported in part by the Israel Science Academy.     

STRATOSPHERIC OZONE DEPLETION BETWEEN 1979 and 1992: IMPLICATIONS FOR BIOLOGICALLY ACTIVE ULTRAVIOLET-B RADIATION and NON-MELANOMA SKIN CANCER INCIDENCE

Abstract— The depletion of stratospheric ozone (0₃) has predictable implications for increases in biologically damaging solar ultraviolet-B radiation (UVB,280–320 nm) reaching the earth's surface. A radiative transfer analysis of satellite-based O₃ measurements between January 1979 and December 1992 shows that surface UVB levels increased substantially at all latitudes except the tropics, if other factors such as cloud cover and local pollutant levels have remained constant over this period. Exposure to UVB radiation is known to induce basal cell and squamous cell skin cancers, and dose-response relationships derived from epidemiological data can be combined with the UVB enhancements to estimate the seasonal and latitudinal distribution of future expected increases in the incidence of these cancers.     

Poisson asymptotics for random projections of points on a high-dimensional sphere

Project a collection of points on the high-dimensional sphere onto a random direction. If most of the points are sufficiently far from one another in an appropriate sense, the projection is locally close in distribution to the Poisson point process.     

Adsorption of fibrinogen on a biomedical-grade stainless steel 316LVM surface: a PM-IRRAS study of the adsorption thermodynamics, kinetics and secondary structure changes

Polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) was employed to investigate the interaction of serum protein fibrinogen with a biomedical-grade 316LVM stainless steel surface, in terms of the adsorption thermodynamics, kinetics and secondary structure changes of the protein. Apparent Gibbs energy of adsorption values indicated a highly spontaneous and strong adsorption of fibrinogen onto the surface. The kinetics of fibrinogen adsorption were successfully modeled using a pseudo first-order kinetic model. Deconvolution of the amide I bands indicated that the adsorption of fibrinogen on 316LVM results in significant changes in the protein's secondary structure that occur predominantly within the first minute of adsorption. Among the investigated structures, the alpha-helix structure undergoes the smallest changes, while the beta-sheet and beta-turns structures undergo significant changes. It was shown that lateral interactions between the adsorbed molecules do not play a role in controlling the secondary structure changes. An increase in temperature induced changes in the secondary structure of the protein, characterized by a loss of the alpha-helical content and its transformation into the beta-turns structure.