Nature based solutions for removal of steroid estrogens in wastewater.

Estrogens are a growing problem in wastewater discharges because they are continuously entering the environment and are biologically active at extremely low concentrations. Their effects on wildlife were first identified several decades before, but the environmental limits and the remedial measures are still not completely elucidated. Most conventional treatment processes were not designed with sufficiently long retention times to effectively remove estrogens.

Model misspecification, measurement error, and apparent supralinearity in the concentration-response relationship between PM2.5 and mortality.

A growing number of studies have produced results that suggest the shape of the concentration-response (C-R) relationship between PM2.5 exposure and mortality is "supralinear" such that incremental risk is higher at the lowest exposure levels than at the highest exposure levels. If the C-R function is in fact supralinear, then there may be significant health benefits associated with reductions in PM2.

Cognitive assessment in primary care: Practical recommendations.

Primary care clinicians play a critical role in both the identification and management of cognitive impairment due to common diseases. Primary care practices should incorporate feasible, reliable, and helpful tools into existing workflow to recognize and support people living with dementia and their care partners.

A simulation-based assessment of the ability to detect thresholds in chronic risk concentration-response functions in the presence of exposure measurement error.

An important question when setting appropriate air quality standards for fine particulate matter (PM2.5) is whether there exists a "threshold" in the concentration-response (C-R) function, such that PM2.5 levels below this threshold are not expected to produce adverse health effects.

Integrated Uncertainty Analysis for Ambient Pollutant Health Risk Assessment: A Case Study of Ozone Mortality Risk.

The U.S. Environmental Protection Agency (EPA) uses health risk assessment to help inform its decisions in setting national ambient air quality standards (NAAQS).

Uncertainty in the estimated risk of lung function decrements owing to ozone exposure.

In the most recent Health Risk and Exposure Assessment (HREA) for Ozone, the US Environmental Protection Agency (EPA) used an exposure-response function estimated on clinical data to calculate the risk of lung function decrements in a series of population-level simulations. These risk estimates are subject to both statistical uncertainty (which arises because the exposure-response function was estimated on a sample of clinical observations) and model uncertainty (which arises because there are different plausible ways to model the relationship between ozone exposure and lung function decrement). In this paper, we describe and apply an approach that allows us to estimate the statistical uncertainty present in these risk estimates.

Developing unit-focused peer coaches for the clinical setting.

In teaching, nursing management, and professional development, the traditional one-to-one approach is used in the peer coach relationship. In clinical environments, the use of peer coaches is a creative way to implement practice change. Tailoring the concept of peer coaching to consider the dynamics and structure of the clinical environment is essential.

Dosimetry of small circular fields for 6-MeV electron beams.

Small field electron beams used in the clinic present complex dosimetry. This investigation reports dosimetric characteristics of small 6-MeV electron field measurements and Monte Carlo calculations, and examines their impact on patient dosimetry. Radiographic film and ionization chamber were used for dosimetric measurements for a 6-MeV electron beam from a Varian 21EX linac.

Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities.

Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities NCRP Report No. 151, 2005, 246 pp. (Hardcover $100).

Is an 192Ir permanent seed implant feasible for prostate brachytherapy?

Purpose: (125)I permanent seed brachytherapy for prostate cancer produces good clinical outcomes and limits radiation exposure to medical staff and patients' families. However, (125)I seeds cost thousands of dollars per implant. An encapsulated (192)Ir permanent seed possibly could cost less than 10 dollars.

Surface and build-up region dosimetry for obliquely incident intensity modulated radiotherapy 6 MV x rays.

This study investigates the surface dose and build-up region dosimetry for oblique IMRT beams. The dependence of surface and build-up region doses of 0 degrees (perpendicular incidence) and 75 degrees (oblique incidence) IMRT fields on field size was measured and compared with open field dosimetry. Measurements were performed using a parallel-plate chamber and KODAK EDR2 films in a polystyrene phantom for a 6 cm x 6 cm and a 12 cm x 12 cm, 6 MV photon beam at depths of 0 mm (surface) through dmax.

Inter-society standards for the performance of brachytherapy: a joint report from ABS, ACMP and ACRO.

Purpose: The proliferation of various brachytherapy modalities for different anatomical sites necessitates the creation of standards for brachytherapy.

Methods: A panel consisting of members of The American Brachytherapy Society (ABS), The American College of Medical Physics (ACMP) and The American College of Radiation Oncology (ACRO) developed standards for the clinical practice and quality assurance (QA) of brachytherapy. These were based upon their clinical experience and a review of the literature.

Effectiveness of compensating filters in the presence of tissue inhomogeneities.

CT based 3D treatment planning systems (3DTPS) can be used to design compensating filters that, in addition to missing tissue compensation, can account for tissue inhomogeneities. The use of computer-driven systems provides a practical, convenient, and accurate method of fabricating compensating filters. In this work, we have evaluated a commercially available PAR Scientific DIGIMILL milling machine linked with FOCUS 3DTPS.

Refined gypsum effective attenuation coefficients for Co-60, 6 MV, 10 MV and 18 MV x-rays.

We report new effective linear attenuation coefficients (mueff) for refined gypsum for Co-60 and 18 MV x-rays. 6 MV and 10 MV mueff agree with published data. For a 100 cm2 field size (FS), tissue defect x = 1.

Nuclear Regulatory Commission regulatory status of approved intravascular brachytherapy systems.

Purpose: To review current and potential future regulatory status of intravascular brachytherapy (IVB) systems.

Methods: There are three approved IVB systems; two commercial IVBs are hand-operated manual devices; the third is remotely operated. In three Guidances, the Nuclear Regulatory Commission (NRC) applied certain regulatory concepts applicable to remotely operated high dose rate (HDR) afterloaders to manually operated IVBs.

Elimination of field size dependence of enhanced dynamic wedge factors.

Enhanced dynamic wedge factors (EDWF) are characterized by a strong field size dependence. In contrast to physical wedge factors, the EDWF decrease as the field size is increased: for 6 MV 60 degrees wedge, the EDWF decreases by 50% when the field size is increased from 4 x 4 cm2 to 20 x 20 cm2. A method that eliminates the field size dependence of EDWF was developed and investigated in this work.

The American Brachytherapy Society recommendations for high-dose-rate brachytherapy for carcinoma of the endometrium.

Purpose: To develop recommendations for use of high-dose-rate (HDR) brachytherapy in patients with endometrial cancer.

Methods: A panel of members of the American Brachytherapy Society (ABS) performed a literature review, supplemented their clinical experience, and formulated recommendations for endometrial HDR brachytherapy.

Results: The ABS endorses the National Comprehensive Cancer Network (NCCN) guidelines for indications for radiation therapy for patients with endometrial cancer and the guidelines on HDR quality assurance of the American Association on Physicists in Medicine (AAPM).

Effect of metal reconstruction plates on cobalt-60 dose distribution: a predictive formula and clinical implications.

Purpose: We sought to create a predictive formula for the dose perturbations caused by head and neck reconstruction plates in the delivery of postoperative radiotherapy with 60Co beams.

Materials And Methods: The dose perturbation effects of Vitallium and Titanium reconstruction plates and flat metal plates of aluminum (13Al), stainless steel (26Fe), tin (50Sn) and lead (82Pb) irradiated with a 60Co beam were measured in polystyrene phantoms using a film dosimetry system. We then used these results to create formulas to predict the effect of a metal reconstruction plate dependent upon its effective atomic number.

The Semliki Forest virus vector induces p53-independent apoptosis.

Three deletion mutants of the structural protein region of the Semliki Forest virus (SFV) genome, including one which encompassed all the viral structural protein genes, induced apoptosis in BHK cells at 48 h after transfection, as shown by DNA laddering and TUNEL staining, as did the wild-type SFV4 RNA. A similar result was obtained for the SFV1 expression vector, which has a multicloning site inserted in place of the structural protein genes. However, in cells transfected with viral RNA containing a deletion of the nsP2 gene, neither viral RNA synthesis nor the induction of apoptosis occurred.

Technique charts for Kodak's new film-screen systems for portal localization.

In July 1996, Kodak released new film-screen systems with enhanced contrast (EC) for portal localization with megavoltage therapeutic beams. This study presents the generation of general-purpose technique charts for Kodak's new film-screen combinations: the Enhanced-Contrast localization (EC-L) film in EC-L cassette and the EC-L film in fast ECL (fECL) cassette for use with cobalt-60, 6 MV, 10 MV, and 18 MV beams. These technique charts were based on the assumption that a film with an optical density (OD) of 1.

High dose-rate brachytherapy treatment delivery: report of the AAPM Radiation Therapy Committee Task Group No. 59.

The goals of this task group are to examine the current high dose-rate (HDR) treatment delivery practices and to prepare a document to assure safe delivery of HDR treatments. The document consists of detailed HDR procedures for design of an HDR brachytherapy program, staffing and training, treatment specific quality assurance, and emergency procedures. The document provides an extensive quality assurance (QA) check list.

Death mechanisms in cultured cells infected by Semliki Forest virus.

We have investigated the induction of cell death in cultured cells by the virulent SFV4 and avirulent A7 strains of Semliki Forest virus (SFV). In BHK cells, death occurred by a typical apoptotic mechanism, as did the death of oligodendrocytes in glial cell cultures. For cerebellar neuron cultures, virus-induced death was due to necrosis.

Sequence analysis of the avirulent, demyelinating A7 strain of Semliki Forest virus.

The nonstructural region of the genome of the avirulent A7 strain of Semliki Forest virus (SFV) has been sequenced, so that the complete nucleotide sequence is available. Compared to the virulent SFV4 strain (produced from the infectious clone pSP6-SFV4), A7 contains 226 nucleotide changes in the translated region, which result in 47 amino acid changes. The 5' nontranslated region has two nucleotide changes, and the 3' nontranslated region is longer in A7 than SFV4, and contains divergent and repeated sequences.