Multiphase radon generation and transport in porous materials

Radon generation and transport in porous materials involve solid, liquid, and gas phases in the processes of emanation, diffusion, advection, absorption, and adsorption. Oversimplifications, such as representing moist soil systems by air-phase emanation and transport models, cause theoretical inconsistencies and biases in resulting calculations. Detailed Rn rate balance equations for solid, liquid, and gas phases were analyzed and combined using phase equilibrium constants to derive a single diffusive-advective rate balance equation in the traditional form. The emanation, diffusion, and permeability coefficients in the new equation have expanded definitions and interpretations to include Rn phase transfer. Radon adsorption was characterized by an exponential moisture dependence, and diffusion and permeability constants utilized previous moisture relationships. Correct boundary and interface conditions were defined, and the unified theoretical approach was applied to field data from a diffusion-dominated system and to laboratory data from an advection-dominated system. Measured 222Rn fluxes and concentrations validated the modeled values within the measurement variability in both applications.     

Paediatric medulloblastoma: Patterns of care and radiotherapy quality assurance in Australia

The purpose of this study was to document how children in Australia with medulloblastoma are being treated and to evaluate the quality of radiotherapy (RT) delivered. The Radiotherapy Database of the Australian and New Zealand Children’s Haematology and Oncology Group was used to identify 46 children with medulloblastoma younger than the age of 15 years treated with radical intent by craniospinal irradiation between 1997 and 1999 inclusively. Twenty‐six patients had completely resected disease without evidence of disease spread. Of these, 16 patients received a craniospinal RT dose of <25 Gy in addition to chemotherapy. RT treatment immobilization methods varied, as did planning methods. RT dose to critical structures was recorded on treatment plans for only 15% of patients. The average systematic error in shield placement at the posterior orbit was 5.2 mm, and two‐thirds of patients were ‘overshielded’ at this site. Adequate coverage of the distal end of the thecal sac was achieved in fewer than 50% of on‐treatment verification films for 21 of 45 patients. With a reduction in RT dose to the craniospinal axis for paediatric medulloblastoma, greater attention is needed for patient immobilization, documentation of RT dose to critical structures and the placement and reproducibility of shielding.     

Sterility testing of insulin preparations

The appearance of precipitates and opalescent components hinders testing for the sterility of insulin suspensions by seeding in cultural media. The sampling procedure is improved by dissolving preparations in 0.2% aqueous ascorbic acid solution, which eliminates opalescence and precipitation and facilitates the reading and interpretation of the test results as the test solutions become transparent. This method is suitable with both direct inoculation and membrane filtration. The insulin solution in 0.2% ascorbic acid does not exhibit antimicrobial activity, which makes expedient testing with the more economical direct inoculation. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 3, pp. 55–56, March, 2007.     

Immune therapy of lupus: what is on the horizon?

Systemic lupus erythematosus (SLE) is a complex disease whichhas posed a continuing challenge to scientists and cliniciansof diverse areas of specialization. It serves as a model forthe study of the mechanisms of autoimmunity—providingan important basis for the development of novel targeted therapiesin lupus and related conditions. The pathophysiology of SLE stems from the abnormal clearanceof apoptotic cells and/or endothelial activation. Material fromdying cells such as apoptotic blebs that are not efficientlyremoved may act as antigenic stimuli and lead to the developmentof autoantibodies with consequent formation of immune complexesand an inflammatory response in a variety of organ systems [1].This     

Pathogenesis and treatment of abdominal pain spinal syndrome

Development of the abdominal pain spinal syndrome is due to alterations in motor segments of the low-thoracic spine which bring about compression and dyscirculatory shifts in the nervous roots and their vegetative branches. Manual therapy was successful in recovery of physiological coordination between elements of the spinal motor segment thus correcting abnormalities in the nervous roots related to compression and affected circulation in 30 out of 36 patients treated.