Spectroscopic approach of the interaction study of Ceftriaxone and human serum albumin

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× 103 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.This work was supported by the German Research Foundation DFG Grant No. DR228/24-2

Inflight proton activation and damage on a CdTe detection plane

Future high-energy space telescope missions require further analysis of orbital environment induced activation and radiation damage on main instruments. A scientific satellite is exposed to the charged particles harsh environment, mainly geomagnetically trapped protons (up to ∼300 MeV) that interact with the payload materials, generating nuclear activation background noise within instruments' operational energy range and causing radiation damage in detector material. As a consequence, instruments' performances deteriorate during the mission time-frame. In order to optimize inflight operational performances of future CdTe high-energy telescope detection planes under orbital radiation environment, we measured and analyzed the effects generated by protons on CdTe ACRORAD detectors with 2.56 cm2 sensitive area and 2 mm thickness. To carry-out this study, several sets of measurements were performed under a ∼14 MeV cyclotron proton beam. Nuclear activation radionuclides' identification was performed. Estimation of activation background generated by short-lived radioisotopes during one day was less than ∼1.3 ×10-5 counts cm-2 s-1 keV-1 up to 800 keV. A noticeable gamma-rays energy resolution degradation was registered (∼60% @ 122 keV, ∼14% @ 511 and ∼2.2% @ 1275 keV) after an accumulated proton fluence of 4.5 ×1010 protons cm-2, equivalent to ∼22 years in-orbit fluence. One year later, the energy resolution of the irradiated prototype showed a good level of performancerecovery