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Electrical and photoelectrical measurements are made at different temperatures on heterojunction photovoltaic cells fabricated by vacuum deposition of n-ZnSe thin films onto p-Si single crystals. A complete study of the current as a function of voltage and temperature is carried out in order to gain fundamental information on trap depth, trap distribution and position of the Fermi level. The results are consistent with space-charge-limited conduction due to an exponentially decreasing distribution of traps. At low voltages, the dark current in the forward direction varies exponentially with voltage. Under reverse bias, the conduction process is interpreted in terms of a transition from electrode-limited Schottky emission to the bulk-limited Poole-Frenkel effect. The values of thermal activation energy for photoconduction and effective density of conducting states are determined and found to be 0.22 eV and 4.4 × 10 17 cm −3 , respectively. These values are estimated from the dependence of photocurrent on temperature at constant illumination with an input power density of 50 mW cm −2 .

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Transthyretin (TTR) aggregation has been characterized to be responsible for several amyloid diseases. Fourier transform infrared (FTIR) spectroscopy, �uorescence, and atomic force microscopy (AFM) are used to investigate secondary structure changes in transthyretin, induced upon thermal denaturation and interaction with pentobarbital. Spectral analysis revealed a strong static quenching of the intrinsic �uorescence of TTR by pentobarbital with a binding constant (�) estimated at 2.092 × 10 3 M −1 . Fourier self-deconvolution (FSD) technique is used to evaluates intensity changes in the spectra of the component bands in the amide I and amide II regions due to the changes in pentobarbital concentration in the protein complex. e increases of the relative intensities of the peaks at 1614 cm −1 and 1507 cm −1 are due to the increase of pentobarbital concentrations which is linked to the formation of oligomers in the protein.

Under physiological conditions, interaction between ceftriaxone and human serum albumin was investigated by using fluorescence spectroscopy and ultra violet (UV) absorption spectrum. From spectral analysis, ceftriaxone showed a strong ability to quench the intrinsic fluorescence of human serum albumin (HSA) through a static quenching procedure. The binding constant (k) is estimated as K=1.02× 10 3 M-1 at 298 K. Fourier transform infrared spectroscopy (FT-IR) spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure and drug binding mechanisms. The observed spectral changes indicated the formation of H-bonding between ceftriaxone and HSA molecules at higher percentage for -helix than for the -sheets.