Coherent photonuclear reactions for isotope transmutation

Coherent photonuclear isotope transmutation (CPIT) produces exclusively radioactive isotopes (RIs) by coherent photonuclear reactions via E1 giant resonances. Photons to be used are medium energy photons produced by laser photons backscattered off GeV electrons. The cross sections are as large as 0.2 - 0.6 b, being independent of individual nuclides. A large fraction of photons is effectively used for the photonuclear reactions, while the scattered GeV electrons remain in the storage ring to be re-used. CPIT with medium energy photons provides specific/desired RIs with the high rate and the high density for nuclear science, molecular biology and for nuclear medicines.Comment: 8 pages, 2 figure

Detection and characterization of biogenic selenium nanoparticles in selenium-rich yeast by single particle ICPMS

A method based on single particle inductively coupled plasma mass spectrometry (SP-ICPMS) was developed for the analysis of commercial Se-rich yeasts, to confirm the occurrence of selenium nanoparticles in these food supplements. A considerable reduction of background levels was achieved by combining data acquisition at microsecond dwell times and the use of a H2 reaction cell, improving by a factor of 10 the current state-of-the-art methodology, and bringing size detection limits down to 18 nm for selenium nanoparticles. The presence of nanoparticulate selenium was revealed by size-exclusion chromatography ICPMS, with detection of a selenium peak at the exclusion volume of the column showing absorption at a wavelength corresponding to selenium nanoparticles. SP-ICPMS allowed us to confirm the presence of Se-nanoparticles, as well as to calculate the nanoparticle size distribution, from information about the shape and elemental composition of the nanoparticles obtained by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS), respectively. These results reveal the significance of nanoparticles in the speciation of metals and metalloids in biological samples and the capability of SP-ICPMS in combination with TEM-EDS to carry out these analyses

Long-term study of antibiotic presence in Ebro river basin (Spain): identification of the emission sources

Water monitoring is key to determining the presence of potentially hazardous substances related to urban activities and intensive farming. This research aimed to perform a long-term (four years) quantitative monitoring of selected antibiotics (azithromycin, enrofloxacin, trimethoprim and sulfadiazine) both in rivers and wastewaters belonging to the Ebro River basin (North of Spain). The target antibiotics were chosen on the basis of a preliminary multispecies screening. The analysis of the antibiotics was carried out by LC-MS/MS on wastewater-treatment plant (WWTP) effluent, effluents of a slaughterhouse and hospital, rivers downstream and upstream of these WWTPs, and rivers close to extensive farming areas. The ANOVA test was performed to study the significant differences between the points exposed to concrete emission sources and antibiotic concentration. The monitoring, carried out from 2018 to 2020, has been essential to illustrating the presence of the most abundant antibiotics that were detected in the Ebro River basin. Enrofloxacin has appeared in river waters in significant concentrations, especially near intensive farming, meanwhile azithromycin has been frequently detected in wastewaters. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland

A nonlinear physiologic pharmacokinetic model: I. Steady-state

The two-compartment model of Rowland et al., (2) has been extended by replacing first order elimination with Michaelis-Menten elimination kinetics. All of the equations for steady-state concentrations and clearances for zero order (constant rate) input orally (into compartment #2) and intravenously (into compartment #1) are derived and reported. The steady-state concentration in compartment #1, following intravenous administration, is shown to be a nonlinear function of maximal velocity of metabolism , V m , the Michaelis constant , K m , and liver blood flow , Q; and, following oral administration is dependent only upon V m and K m and is independent of Q. However, oral bioavailability is a function of V m , K m , and Q. The model allows physiologic pharmacokinetic interpretation of both linear and nonlinear data; and, together with simple modification of the model, can explain much observed pharmacokinetic data to date particularly for first-pass drugs. Future articles in the series will be concerned with single doses, evaluation of literature data in terms of the model, application of the theory in toxicology and in clinical pharmacokinetics and therapeutics .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45033/1/10928_2005_Article_BF01073657.pd

Pharmacokinetics of ibuprofen in man. I. Free and total area/dose relationships

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110022/1/cptclpt1983136.pd

Numerical Study of a Mixed Ising Ferrimagnetic System

We present a study of a classical ferrimagnetic model on a square lattice in which the two interpenetrating square sublattices have spins one-half and one. This model is relevant for understanding bimetallic molecular ferrimagnets that are currently being synthesized by several experimental groups. We perform exact ground-state calculations for the model and employ Monte Carlo and numerical transfer-matrix techniques to obtain the finite-temperature phase diagram for both the transition and compensation temperatures. When only nearest-neighbor interactions are included, our nonperturbative results indicate no compensation point or tricritical point at finite temperature, which contradicts earlier results obtained with mean-field analysis.Comment: Figures can be obtained by request to [email protected] or [email protected]

Your space or mine? : Mapping self in time

Peer reviewedPublisher PD