Gamma-ray computed tomography to characterize soil surface sealing.

The application of sewage sludge as a fertilizer on soils may cause compacted surface layers (surface sealing), which can promote changes on soil physical properties. The objective of this work was to study the use of gamma-ray computed tomography, as a diagnostic tool for the evaluation of this sealing process through the measurement of soil bulk density distribution of the soil surface layer of samples subjected to sewage sludge application. Tomographic images were taken with a first generation tomograph with a resolution of 1 mm. The image analysis opened the possibility to obtain soil bulk density profiles and average soil bulk densities of the surface layer and to detect the presence of soil surface sealing. The sealing crust thickness was estimated to be in the range of 2-4 mm.     

Use of 137Cs measurements to estimate changes in soil erosion rates associated with changes in soil management practices on cultivated land.

Intensification of agricultural production in south-central Chile since the 1970s has caused problems of increased soil erosion and associated soil degradation. These problems have prompted a shift from conventional tillage to no-till management practices. Faced with the need to establish the impact of this shift in soil management on rates of soil loss, the use of caesium-137 (137Cs) measurements has been explored. A novel procedure for using measurements of the 137Cs depth distribution to estimate rates of soil loss at a sampling point under the original conventional tillage and after the shift to no-till management has been developed. This procedure has been successfully applied to a study site at Buenos Aires farm near Carahue in the 9th region of Chile. The results obtained indicate that the shift from conventional tillage to no-till management has caused net rates of soil loss to decrease to about 40% of those existing under conventional tillage. This assessment of the impact of introducing no-till management at the study site must, however, be seen as provisional, since only a limited number of sampling points were used. A simplified procedure aimed at documenting the reduction in erosion rates at additional sampling points, based solely on measurements of the 137Cs inventory of bulk cores and the 137Cs activity in the upper part of the soil has been developed and successfully tested at the study site. Previous application of 137Cs measurements to estimate erosion rates has been limited to estimation of medium-term erosion rates during the period extending from the beginning of fallout receipt to the time of sampling. The procedures described in this paper, which permits estimation of the change in erosion rates associated with a shift in land management practices, must be seen as representing a novel application of 137Cs measurements in soil erosion investigations.     

Thyroid function changes related to use of iodinated water in the U.S. Space Program

BACKGROUND: The National Aeronautics and Space Administration (NASA) has used iodination as a method of microbial disinfection of potable water systems in U.S. spacecraft and long-duration habitability modules. A review of thyroid function tests of NASA astronauts who had consumed iodinated water during spaceflight was conducted. METHODS: Thyroid function tests of all past and present astronauts were reviewed. Medical records of astronauts with a diagnosis of thyroid disease were reviewed. Iodine consumption by space crews from water and food was determined. Serum thyroid-stimulating hormone (TSH) and urinary iodine excretion from space crews were measured following modification of the Space Shuttle potable water system to remove most of the iodine. RESULTS: Mean TSH significantly increased in 134 astronauts who had consumed iodinated water during spaceflight. Serum TSH, and urine iodine levels of Space Shuttle crewmembers who flew following modification of the potable water supply system to remove iodine did not show a statistically significant change. There was no evidence supporting association between clinical thyroid disease and the number of spaceflights, amount of iodine consumed, or duration of iodine exposure. CONCLUSIONS: It is suggested that pharmacological doses of iodine consumed by astronauts transiently decrease thyroid function, as reflected by elevated serum TSH values. Although adverse effects of excess iodine consumption in susceptible individuals are well documented, exposure to high doses of iodine during spaceflight did not result in a statistically significant increase in long-term thyroid disease in the astronaut population.     

CT of the bowel: use of water to enhance depiction

To enhance computed tomography (CT) of the bowel walls, water was administered into the colon through the rectum in 42 patients: 16 with rectal cancer, 22 with other colon carcinomas, and four with tumors originating in the pelvic organs. The technique provided a good evaluation of the bowel walls; the presence and extension of the intestinal tumors was assessed in all cases, and infiltrations of the bowel wall from the pelvic tumors were excluded.     

Enhancing the precision of quantitative water content mapping by optimizing sequence parameters.

This article describes a methodology for determining the precision of a recently published method for quantitative water content mapping using MRI. A framework for calculating the random error component as a function of sequence parameters is provided and predictions are compared with experimental results obtained in a phantom. The experimental and theoretical results are in good agreement and demonstrate that the precision of quantitative water content mapping can be significantly increased by a proper and objective choice of acquisition parameters.     

Examining the use of different sample types following decomposition to estimate year of death using bomb pulse dating

When human remains are discovered, confirming the identification of the decedent is the first part of the forensic medical investigation. In cases where the remains are skeletonised or badly decomposed, differential preservation often increases the difficulty of this task. Bomb pulse dating, which directly compares levels of 14 C within human tissues to atmospheric levels, can provide an estimate of the year of death, which may assist in the identification process. This study measured the 14 C content in samples of hair, nail and puparia collected from donors at the Australian Facility for Taphonomic Experimental Research (AFTER). The radiocarbon results demonstrated that the nail samples provided the most accurate year of death estimation, with 91% correctly predicting YOD, closely followed by hair, with a 79% correct prediction rate, with both hair and nails having a lag time of 0–1 years. This is consistent with the time taken for atmospheric CO 2 to enter the food chain, and be taken in by humans. Puparia was found to have the highest levels of 14 C, and was the least consistent with the actual YOD (46% correct). However, predicted YOD ranges were still within 4 years of the actual YOD. Based on the results of this study, hair, nail and puparia should be considered as useful samples to obtain accurate estimates for YOD using bomb pulse dating.     

The accuracy of the TriTrac-R3D accelerometer to estimate energy expenditure.

PURPOSE: This study examined the reliability and validity of the TriTrac-R3D triaxial accelerometer to estimate energy expenditure during various modes of exercise. METHODS: Twenty subjects (age = 21.5+/-3.4 yr; body mass index = 23.3+/-3.6 kg x m(-2)) performed five exercises (treadmill walking, treadmill running, stepping, stationary cycling, and slideboard), with each lasting 20-30 min and workload increased at 10-min intervals. To test the inter-TriTrac reliability, two TriTrac-R3D accelerometers were worn during each exercise period, and to examine validity, a simultaneous measurement of energy expenditure was made using indirect calorimetry (SensorMedics 2900 Metabolic Cart). RESULTS: Results showed a significant correlation between the two TriTrac-R3D accelerometers during all exercises. The difference in estimated energy expenditure between the two accelerometers during the walking, stepping, and slideboard exercises was less than 1 kcal x min(-1) but statistically significant (P<0.05). There was also a significant correlation between energy expenditure estimated by each of the TriTrac-R3D accelerometers and indirect calorimetry during walking, running, stepping, and slideboard exercise (P<0.05). The interaction of Method x Workload was significant (P<0.05) for each exercise, indicating that the TriTrac-R3D underestimates energy expenditure and that the magnitude of this underestimation increases as workload increases. CONCLUSIONS: Therefore, energy expenditure estimated via triaxial accelerometry does not increase with increasing workloads. These results suggest that there are limitations to using triaxial accelerometry to quantify energy expenditure.     

Dynamics of 95Zr in the rice/water/soil system.

In order to get a better understanding of the environmental behavior of 95Zr and to generate fundamental data for evaluation of its ecological risk, an experiment was conducted to study 95Zr dynamics in a simulated rice/water/soil system. The results showed that the concentration of 95Zr in surface water decreased rapidly with time due to precipitation, adsorption to soil and uptake by rice, and most of 95Zr in soil was found concentrated in the surface layer (0-8 cm from surface). The 95Zr could not readily move downwards with percolating water and remained in surface soil. The 95Zr taken up from surface water and surface soil mainly concentrated in roots and lower parts of stem. The concentration of 95Zr in upper part of stem and leaves were relatively lower, which were only slightly greater than the detection limit. The 95Zr concentration in tassel was near the detection limit. The dynamics of 95Zr concentrations in rice, water and soil can be described with exponential function.     

MicroRNA profiling of gastric content from breast-fed and formula-fed infants to estimate last feeding: a pilot study

International Journal of Legal Medicine - Recently, we were consulted about a challenging case, where an infant died by poisoning and the drug-dependent mother insisted that she unintentionally...     

Simultaneous heart rate-motion sensor technique to estimate energy expenditure.

PURPOSE: Heart rate (HR) and motion sensors represent promising tools for physical activity (PA) assessment, as each provides an estimate of energy expenditure (EE). Although each has inherent limitations, the simultaneous use of HR and motion sensors may increase the accuracy of EE estimates. The primary purpose of this study was to establish the accuracy of predicting EE from the simultaneous HR-motion sensor technique. In addition, the accuracy of EE estimated by the simultaneous HR-motion sensor technique was compared to that of HR and motion sensors used independently. METHODS: Thirty participants (16 men: age, 33.1 +/- 12.2 yr; BMI, 26.1 +/- 0.7 kg.m(-2); and 14 women: age, 31.9 +/- 13.1 yr; BMI, 27.2 +/- 1.1 kg.m(-2) (mean +/- SD)) performed arm and leg work in the laboratory for the purpose of developing individualized HR-VO2 regression equations. Participants then performed physical tasks in a field setting for 15 min each. CSA accelerometers placed on the arm and leg were to discriminate between upper and lower body movement, and HR was then used to predict EE (METs) from the corresponding arm or leg laboratory regression equation. A hip-mounted CSA accelerometer and Yamax pedometer were also used to predict EE. Predicted values (METs) were compared to measured values (METs), obtained via a portable metabolic measurement system (Cosmed K4b(2)). RESULTS: The Yamax pedometer and the CSA accelerometer on the hip significantly underestimated the energy cost of selected physical activities, whereas HR alone significantly overestimated the energy cost of selected physical activities. The simultaneous HR-motion sensor technique showed the strongest relationship with VO(2) (R(2) = 0.81) and did not significantly over- or underpredict the energy cost (P = 0.341). CONCLUSION: The simultaneous HR-motion sensor technique is a good predictor of EE during selected lifestyle activities, and allows researchers to more accurately quantify free-living PA.     

Changes of contents of CO and water in blood exposed to heat—as to a possibility of estimating pre-exposure CO content of thermally coagulated blood on the basis of its water content

Summary A blood sample containing CO in a glass vessel was heated in a thermostated water bath at various temperatures for varying lengths of time to compare changes in CO and water contents.With higher temperatures and longer exposure periods the degrees of thermocoagulation advanced and the contents of CO and water decreased. At the individual temperatures examined, changes of CO and water contents showed significant correlations. However, with different temperatures regressions differed significantly. The above was considered to show that the temperature, to which a blood sample had been exposed, must be known for successful application of the water content method to estimate pre-exposure CO content of heat-exposed blood.However, this requirement is considered difficult to be met.     

Microwave sensing of increased intracranial water content

A new technique to monitor brain edema is described that uses microwave energy to detect increased intracranial water content. By recording the phase of a transmitted microwave signal, increases in intracranial water content on the order of 1% are detected in vivo. These findings suggest that the progression of brain edema on a long-term basis can be assessed by progression of brain edema on a long-term basis can be assessed by our technique. Furthermore, phase changes related to small intracranial pressure variations are observed, indicating that the detection of pathologic pressure variations such as Traube-Hering-Mayer waves and plateau waves is possible by a noninvasive microwave technique.     

The use of absorbers to optimize the surface dosage in treatment using ultrahard x-rays

The surface dose in megavoltage x-ray therapy can be modified using two different techniques: either varying the thickness of an absorber positioned directly on the surface of the patient or varying the distance to the surface of an absorber with constant thickness. Surface dose as a function of distance and absorber thickness has been measured at 4 MV and 8 MV x-rays. Both methods yield sufficiently and well-defined dose enhancements at the surface of the patient as desired clinically. The variation of the absorber-surface distance however has been proved to be the more simple and practicable method, offering the additional advantage of no contacting the patients skin.     

Chromosome aberration dosimetry. II. Addition of thymidine to culture medium does not modify the dose estimate.

The present experiments were carried out on mixtures of male irradiated and female non-irradiated lymphocytes, using the Y chromosome as a marker. The results demonstrate that in vitro synchronisation of cells by a thymidine block which generally improves the preparation does not interfere with the estimate of the averaged whole body dose after homogeneous exposure or the fraction of the blood irradiated and the dose after inhomogeneous exposure.     

A progressive shuttle run test to estimate maximal oxygen uptake.

The purpose of the present study was to examine the validity of using a 20 m progressive shuttle run test to estimate maximal oxygen uptake. Running ability was described as the final level attained on the shuttle run test and as time on a 5 km run. Maximal oxygen uptake (VO2 max) was determined directly for seventy-four volunteers (36 men, 38 women) who also completed the shuttle run test. Maximal oxygen uptake values were 58.5 +/- 7.0 and 47.4 +/- 6.1 ml.kg-1.min-1 for the men and women respectively (mean +/- SD, P less than 0.01). The levels attained on the shuttle run test were 12.6 +/- 1.5 (men) and 9.6 +/- 1.8 (women; P less than 0.01). The correlation between VO2 max and shuttle level was 0.92. The correlation between VO2 max and the 5 km run was -0.94 and the correlation between both field tests was -0.96. The results of this study suggest that a progressive shuttle run test provides a valid estimate of VO2 max and indicates 5 km running potential in active men and women.     

Bone metabolic markers as gauges of metastasis to bone: a review

Currently, imaging techniques are the leading methods used to diagnose of metastasis to bone. However, these techniques are expensive, expose patients to toxic and radioactive compounds, and monitor response to treatment poorly; these drawbacks have prompted the search for alternative screening methods. Therefore, bone metabolic markers have been evaluated as possible methods to diagnose and monitor the development and progression of metastatic bone disease. Although bone metabolic markers are often grouped as either resorption or formation markers, studies have revealed that each marker has its own biologic meaning and clinical relevance. Recent milestones in the use of bone metabolic markers as screening methods for metastatic bone disease and as evaluation methods for treatment response are shown in the following lists. 1. Bone metabolic marker measurements provide insight into mechanisms of metastasis to bone. 2. Although promising data have been reported, bone metabolic markers are not yet considered to be reliable screening methods for metastasis to bone. 3. Bone metabolic markers are reliable indicators of response to both conventional and bisphosphonate therapies. 4. Preliminary results indicate bone metabolic markers might be an independent prognostic factor in patients whose tumors metastasize to bone. 5. New or refined assays for bone metabolic markers are expected to improve the sensitivity and specificity of bone metabolic marker use in diagnosing and monitoring metastasis to bone.