High-Resolution 4D Preclinical Single-Photon Emission Computed Tomography/X-ray Computed Tomography Imaging of Technetium Transport within a Heterogeneous Porous Media.

A dynamic 99mTc tracer experiment was performed to investigate the capabilities of combined preclinical single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) for investigating transport in a heterogeneous porous medium. The experiment was conducted by continuously injecting a 99mTc solution into a column packed with eight layers (i.e., soil, silica gel, and 0.2-4 mm glass beads). Within the imaging results it was possible to correlate observed features with objects as small as 2 mm for the SPECT and 0.2 mm for the CT. Time-lapse SPECT imaging results illustrated both local and global nonuniform transport phenomena and the high-resolution CT data were found to be useful for interpreting the cause of variations in the 99mTc concentration associated with structural features within the materials, such as macropores. The results of this study demonstrate SPECT/CT as a novel tool for 4D (i.e., transient three-dimensional) noninvasive imaging of fate and transport processes in porous media. Despite its small scale, an experiment with such high resolution data allows us to better understand the pore scale transport which can then be used to inform larger scale studies.

Hydraulic Conductivity Fields: Gaussian or Not?

Hydraulic conductivity (K) fields are used to parameterize groundwater flow and transport models. Numerical simulations require a detailed representation of the K field, synthesized to interpolate between available data. Several recent studies introduced high resolution K data (HRK) at the Macro Dispersion Experiment (MADE) site, and used ground-penetrating radar (GPR) to delineate the main structural features of the aquifer. This paper describes a statistical analysis of these data, and the implications for K field modeling in alluvial aquifers. Two striking observations have emerged from this analysis. The first is that a simple fractional difference filter can have a profound effect on data histograms, organizing non-Gaussian ln K data into a coherent distribution. The second is that using GPR facies allows us to reproduce the significantly non-Gaussian shape seen in real HRK data profiles, using a simulated Gaussian ln K field in each facies. This illuminates a current controversy in the literature, between those who favor Gaussian ln K models, and those who observe non-Gaussian ln K fields. Both camps are correct, but at different scales.

Colorectal cancer screening behaviors.

INTRODUCTION: Colorectal cancer screening program compliance in Turkey is around 20-30%. Factors that may affect preventive health behavior, mainly individuals' values, beliefs and attitudes, should be explored. A "Health Belief Model" (HBM) scale was developed in 1950 to explain the insufficient participation of some individuals in screening programs. The scale was adopted for colon cancer in 2002. The validity and reliability study of this scale for the Turkish language was conducted in 2007. In this study we aim to evaluate the health beliefs of relatively young individuals before the age of screening in relation to attitudes to colorectal cancer screening via the Turkish version of the scale. MATERIALS AND METHODS: A questionnaire composed of 14 sociodemographic questions and 33 HBM scale questions were applied to the patients of a Family Medicine outpatient clinic where the majority of the patients are relatively young people. The data was analyzed using the IBM SPSS version 21.0. RESULTS: A total of 310 subjects at the age of 18 and over were informed about the study. The study was completed with 215 subjects with a participation rate of 69.3%. The average age of the participants was 35.4 ± 12.8 years; 62.8% of them were women; 26.0% were students. 94.4% of the participants did not have a history of colon cancer among their first degree relatives. 58.1% agreed that "A colonoscopy should be done every ten years starting at age 50 to screen for colon cancer." Age, marital status, education and occupation status were found to have an effect on barrier scores. Young participants, singles, and those with a primary and/or secondary school education had statistically significant higher barrier scores. The motivation scores of high school graduates were higher than university graduates. The seriousness scores of men were found to be higher than women. CONCLUSION: Our study points out that attitudes about preventive health measures are mainly associated with age, gender, education level and marital status. These personal characteristics should be taken into consideration while offering screening programs and preventive health measures to individuals in order to protect against colorectal cancer. It is better to give specific messages according to personal characteristics and specific barriers instead of general messages about conducting screening tests beginning from a young age.