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This report describes a two-year effort to survey the internal 137Cs and external β-emitter contamination present in the feral dog population near the Chernobyl nuclear power plant (ChNPP) site, and to understand the potential for human radiation exposure from this contamination. This work was performed as an integral part of the radiation safety and control procedures of an animal welfare oriented trap-neuter-release (TNR) program. The measurement program focused on external contamination surveys using handheld β-sensitive probes, and internal contamination studies using a simple whole-body counter. Internal 137Cs burden was measured non-invasively during post-surgical observation and recovery. External β contamination surveys performed during intake showed that 21/288 animals had significant, removable external contamination, though not enough to pose a large hazard for incidental contact. Measurements with the whole-body counter indicated internal 137Cs body burdens ranging from undetectable (minimum detection level ∼100 Bq/kg in 2017, ∼30 Bq/kg in 2018) to approximately 30,000 Bq/kg. A total of 33 animals had 137Cs body-burdens above 1 kBq/kg, though none posed an external exposure hazard. The large variation in the 137Cs concentration in these animals is not well-understood, could be due to prey selection, access to human food scraps, or extended residence in highly contaminated areas. The small minority of animals with external contamination may pose a contamination risk allowing exposures in excess of regulatory standards.

The self-assembly of multiblock copolymers in solutions is controlled by a delicate balance between inherent phase segregation due to incompatibility of the blocks and the interaction of the individual blocks with the solvent. The current study elucidates the association of pentablock copolymers in a mixture of selective solvents which are good for the hydrophobic segments and poor for the hydrophilic blocks using small angle neutron scattering (SANS). The pentablock consists of a center block of randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability. We find that the pentablock forms ellipsoidal core-shell micelles with the sulfonated polystyrene in the core and Gaussian decaying chains of swollen poly-ethylene-r-propylene and poly-t-butyl styrene tertiary in the corona. With increasing solution concentration, the size of the micelle, the thickness of the corona, and the aggregation number increase, while the solvent fraction in the core decreases. In dilute solution the micelle increases in size as the temperature is increased, however, temperature effects dissipate with increasing solution concentration. [ABSTRACT FROM AUTHOR]

Abstract: The effect of neutralization with Et3Al on morphologies in a sulfonated pentablock copolymer solution and cast membrane was investigated using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The sulfonated pentablock copolymer in a non-polar solvent mixture (cyclohexane/heptane) persists as spherical micelles after neutralization where the micelle core of sulfonated polystyrene (SS) incorporates Al (3+) ions and the corona is solvated hydrogenated isoprene (HI) and t-butylstyrene (tBS). Membranes cast from this micellar solution exhibit a bicontinuous microphase separated morphology with interconnected SS microdomains. The aluminum-neutralized membrane with a continuous transport channel shows excellent water vapor transport rate (WVTR) (22kg/(m2 day)), which is comparable to the WVTR of membranes in the sulfonic acid form. The strong interaction between Al(3+) ions and the sulfonic acid group in the aluminum-neutralized membrane results in significantly lower water uptake (∼30wt%) that provides much-improved mechanical stability in the wet state. [Copyright &y& Elsevier]

Suspension-phase neutralization of an acid-form sulfonatedstyrenicpentablock copolymer was used to prepare aluminum cross-linked polymerfilms. Aluminum neutralization was confirmed by 27Al solidstate NMR, and the aluminum-neutralized polymer resisted ion exchangeto the sodium counterion form when the polymer was soaked in 1 mol/Lsodium chloride for 30 days. The effects of aluminum neutralizationon polymer morphology, mechanical properties, water and salt transportproperties, and free volume were explored. The primary spacing ofthe morphology, as measured by small-angle X-ray scattering (SAXS),decreased upon neutralization of the sulfonated polymer. The hydratedaluminum-neutralized polymer was mechanically stronger than the non-neutralizedpolymer, but the dry aluminum-neutralized polymer was more brittlethan the non-neutralized polymer. Neutralization of the polymer’ssulfonic acid functionality resulted in a 5.5-fold decrease in wateruptake. This water uptake decrease upon aluminum neutralization resultedin a decrease, relative to the non-neutralized polymer, in water andsodium chloride permeability and water vapor transport rate. Thesedecreases in transport rates and water uptake were consistent withone another, based on an analysis of changes in free volume of thematerial upon aluminum neutralization. Sodium chloride permeabilityof the aluminum-neutralized polymer was less dependent on salt concentrationthan that of the non-neutralized polymer, which is consistent withneutralization of the polymer’s charged sulfonate groups. Aluminumneutralization increased the polymer’s water/sodium chloridepermeability selectivity because of a 1.8-fold increase in the material’sdiffusion selectivity. Free volume element size, characterized by ortho-positronium lifetime, decreased upon aluminum neutralizationin both dry and hydrated film samples. [ABSTRACT FROM AUTHOR]

In an attempt to exploit bcl-2 overexpression and aberrant p53 function, two frequently encountered aberrations that predict marked treatment resistance and worse prognosis in patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin’s lymphoma (NHL), we combined theophylline, pentostatin, and chlorambucil at two dose levels (cohort I: 30 mg/m2; cohort II: 20 mg/m2) on a 21-day cycle for up to six courses. We employed a phase I/II design to determine feasibility, define the maximum tolerated dose (MTD), and explore the impact of biologic modulation on response and time to progression (TTP) in 20 patients with relapsed or refractory CLL and NHL. Eight patients were enrolled in cohort I. They demonstrated a response rate (RR) of 28% and a 16.5-month TTP after receiving a median of two cycles. A 50% RR was observed in this cohort when patients with adverse histologies were excluded. Because of myelotoxicity, this dose level defined the MTD, and de-escalation occurred. All 12 patients in cohort II received 20 mg/m2 chlorambucil. A 50% RR and an 18-month TTP were observed after a median of 5.5 cycles. An RR of 47% and a complete remission (CR) of 5% were observed for the entire group, although responses and TTP varied greatly by histology. Significant activity was observed in patients with B-cell CLL and follicular lymphoma (FL). RR and TTP for fludarabine-sensitive/naïve and fludarabine-refractory (FR) B-cell CLL patients were 66 vs 25% and 20 vs 8.5 months, respectively. Both FL patients responded (one with partial remission and one with CR), with a 22.5-monthly median TTP. For responding patients, median TTP and overall survival (OS) was 21 and 69 months, respectively, compared to a median TTP of 2 months and an OS of 13.5 months for nonresponders. The combination of pentostatin, chlorambucil, and theophylline is the active regimen in patients with FL and B-cell CLL. [ABSTRACT FROM AUTHOR]

Investigates the induction of apoptosis in human B-cell chronic lymphocytic leukemia (CLL) cells by carboxyamido-triazole (CAI), a novel 'static' signal transduction inhibitor. Patient characteristics; Role of tumor reduction and disease stabilization in CLL; Detection of apoptosis in CLL cells.

An important element in the development of advanced neutron detectors is the synthesis and characterization of improved, highly efficient neutron-scintillating materials. The research described here concerns the development of elastic, transparent, and thick film neutron scintillators with high [sup 6]Li[sup +] loading through room-temperature sol-gel processing. The room-temperature sol-gel processing allows an easy integration of such scintillating materials into electronic detecting devices. The lithium-6 salicylate di-ureasil xerogels developed here show promise for the fabrication of large area neutron detectors and have high potential for use in in situ monitoring and imaging of fissile materials and radioactive contaminants. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]