Radiolytic degradation of selective actinide extractants from the bis-1,2,4-triazine family in cyclohexanone solutions.

Early stages of radiolysis of solutions with 2,6-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4]triazin-3-yl)pyridine (CyMe4-BTP) and 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4-]triazin-3-yl)-[2,2']bipyridine (CyMe4-BTBP) ligands in cyclohexanone, proposed as a solvent for selective actinide extraction, were studied by means of the pulse radiolysis technique with spectrophotometric detection. Transient UV-vis spectra of excited triplet states of ligands, formed by energy transfer from cyclohexanone excited triplet states to ligands, were recorded for the first time. The influence of typical extraction conditions (the presence of diluted acid and O from air) on the mechanisms of reactions in the system studied was assessed.

Hydroxyl Radical vs. One-Electron Oxidation Reactivities in an Alternating GC Double-Stranded Oligonucleotide: A New Type Electron Hole Stabilization.

We examined the reaction of hydroxyl radicals (HO) and sulfate radical anions (SO), which is generated by ionizing radiation in aqueous solutions under anoxic conditions, with an alternating GC doubled-stranded oligodeoxynucleotide (ds-ODN), i.e., the palindromic 5'-d(GCGCGC)-3'.

Risk and protective factors associated with internalizing and externalizing mental health problems among 13-15-year-old youth.

Objectives: The main aim of the research was to identify factors associated with the occurrence of mental health problems in adolescents.

Methods: The study group consisted of elementary and junior high school students from Ilawa aged 13-15 years (N=574). The self-administered, anonymous questionnaire had been completed during school lessons.

Remote EPID-based dosimetric auditing using DVH patient dose analysis.

The aim of this work was to develop and validate a method for remote dosimetric auditing that enables dose-volume histogram parameter comparisons of measured and planned dose in the patient CT volume.. The method is derived by adapting and combining a remote electronic portal imaging (EPID) based auditing method (Virtual Epid based Standard Phantom Audit-VESPA) and a method to estimate 3D in-patient dose distributions from planar dosimetric measurements.

Evaluation of Hydroxyl Radical Reactivity by Thioether Group Proximity in Model Peptide Backbone: Methionine versus S-Methyl-Cysteine.

Hydroxyl radicals (HO) have long been regarded as a major source of cellular damage. The reaction of HO with methionine residues (Met) in peptides and proteins is a complex multistep process. Although the reaction mechanism has been intensively studied, some essential parts remain unsolved.