Second primary cancers after radiation for prostate cancer: a review of data from planning studies

A review of planning studies was undertaken to evaluate estimated risks of radiation induced second primary cancers (RISPC) associated with different prostate radiotherapy techniques for localised prostate cancer. A total of 83 publications were identified which employed a variety of methods to estimate RISPC risk. Of these, the 16 planning studies which specifically addressed absolute or relative second cancer risk using dose–response models were selected for inclusion within this review. There are uncertainties and limitations related to all the different methods for estimating RISPC risk. Whether or not dose models include the effects of the primary radiation beam, as well as out-of-field regions, influences estimated risks. Regarding the impact of IMRT compared to 3D-CRT, at equivalent energies, several studies suggest an increase in risk related to increased leakage contributing to out-of-field RISPC risk, although in absolute terms this increase in risk may be very small. IMRT also results in increased low dose normal tissue irradiation, but the extent to which this has been estimated to contribute to RISPC risk is variable, and may also be very small. IMRT is often delivered using 6MV photons while conventional radiotherapy often requires higher energies to achieve adequate tissue penetration, and so comparisons between IMRT and older techniques should not be restricted to equivalent energies. Proton and brachytherapy planning studies suggest very low RISPC risks associated with these techniques. Until there is sufficient clinical evidence regarding RISPC risks associated with modern irradiation techniques, the data produced from planning studies is relevant when considering which patients to irradiate, and which technique to employ

Byssinosis in a textile factory in Cameroon: a preliminary study.

To assess the risk of byssinosis in a cotton textile factory in Cameroon a preliminary study was conducted on a random sample of 125 men from production areas and 68 men from non-production areas. Symptoms were assessed by a questionnaire, which also included questions regarding sleep; peak expiratory flow rate (PEF) was measured with a miniature peak flow meter at the end of a working day and total dust concentrations were assessed by static and personal sampling with Casella dust samplers giving values of 6.4 +/- 2.6 mg/m3 (m +/- SD) in production areas and 1.7 +/- 0.7 mg/m3 in control areas. Exposed subjects had significantly more symptoms (particularly in smokers) and lower PEF values than controls (408 +/- 961/min v 468 +/- 701/min, p less than 0.001). Twenty three exposed subjects (18%) reported chest tightness on returning to work after the weekly break (compared with one control, p less than 0.01). Subjects with byssinosis had lower PEF values than those without chest tightness (356 +/- 501/min v 426 +/- 951/min, p less than 0.01), more chronic bronchitis (52% v 6%, p less than 0.001), they were more often smokers (61% v 31%, p less than 0.05), and came generally, though not exclusively, from the opening carding spinning department with the highest concentrations of total dust (8 +/- 2 mg/m3) and an estimated prevalence of byssinosis of 28%. There were no significant differences in sleep related symptoms between the exposed and controls, though the 23 subjects with byssinosis tended to report more snoring (48%), early morning headache (48%), and sleep improvement over the working week (44%) than all the other subjects (28%, 24%, and 24% respectively, p less than 0.1)

A workflow for cooperative inversion of seismic and magnetotelluric data

We present a cooperative inversion approach for acoustic impedance using seismic and magnetotelluric data. In this approach, the magnetotelluric data, sensitive to the resistivity of rocks are used to get the large scale background spatial trends of the acoustic impedance model, while the seismic data are used to get the small-scale features. The connections between resistivity and elastic properties of rocks are obtained from petrophysical relationships derived from borehole data. Structural constraints derived from seismic are used to improve the magnetotelluric inversion. We present an application of this technique to synthetic data derived from previous interpretation of seismic and magnetotelluric models in a mineral province. The synthetic example shows how an improved result is obtained using our cooperative inversion workflow

Analyzing Creep-Recovery Behavior of Tropical Entandrophragma cylindricum Wood: Traditional and Fractional Modeling Methods

International audienceNowadays, wood stands as one of the foremost used construction materials, owing largely to its exceptional physical and mechanical properties. Ensuring the safety of timber structures necessitates thorough investigations into the influential phenomena that significantly affect their strength and longevity. The aim of this paper is to study the coupled creep-recovery behavior of tropical wood from the Entandrophragma cylindricum species by evaluating the influence of stress levels on the performance of rheological models. Hence, the Burger and Weibull classic models were introduced to elucidate these phenomena. These models have been compared with the fractional Maxwell and Zener models. Following the simulations, the Burger classic model effectively characterized creep and recovery, comprising elastic, viscoelastic, and viscous elements arranged in series, as well as the classic Weibull model. During the recovery phase, the four-parameter Weibull model demonstrated a satisfying description, achieving 99% accuracy compared to 97% for the four-parameter Burger classic model. Three-parameter fractional Maxwell model fit all phases of the process for all deformations with an average accuracy of 98% for creep and 95% for recovery. These results provide valuable information on the material's ability to recover from deformation and offer essential insights for materials characterization, engineering design, and quality assurance processes in materials engineering.</div