A nonparametric measure of noise in x-ray diagnostic images-mammography

Objective.In x-ray diagnostics, modern image reconstruction or image processing methods may render established methods of image quality assessment inadequate. Task specific quality assessment by using model observers has the disadvantage of being very labour-intensive. Therefore, it appears highly desirable to develop novel image quality parameters that neither rely on the linearity and the shift-invariace of the imaging system nor require the acquisition of hundreds of images as is necessary for the application of model observers, and which can be derived directly from diagnostic images.Approach.A new measure for the noise based on non-maximum-suppression images is defined and its properties are explored using simulated images before it is applied to an exposure series of mammograms of a homogeneous phantom and a 3D-printed breast phantom to demonstrate its usefulness under realistic conditions.Main results.The new noise parameter cannot only be derived from images with a homogeneous background but it can be extracted directly from images containing anatomic structures and is proportional to the standard deviation of the noise. At present, the applicability is restricted to mammography, which satisfies the assumption of short covariance length of the noise.Significance.The new measure of the noise is but a first step of the development of a set of parameters that are required to quantify image quality directly from diagnostic images without relying on the assumption of a linear, shift-invariant system, e.g. by providing measures of sharpness, contrast and structural complexity, in addition to the noise measure. For mammography, a convenient method is now available to quantify noise in processed diagnostic images.

Mechanisms and thermodynamic modelling of iodide sorption on AFm phases

Both, experimental and modelling evidence is presented in this study showing that interlayer anion exchange is the dominant sorption mechanism for iodide (I^-) on AFm phases. AFm phases are Ca-Al(Fe) based layered double hydroxides (LDH) known for their large potential for the immobilization of anionic radionuclides, such as dose-relevant iodine-129, emanating from low- and intermediate-level radioactive waste (L/ILW) repositories. Monosulfate, sulfide-AFm, hemicarbonate and monocarbonate are safety-relevant AFm phases, expected to be present in the cementitious near-field of such repositories. Their ability to bind I^- was investigated in a series of sorption and co-precipitation experiments. The sorption of I^- on different AFm phases was found to depend on the type of the interlayer anion. Sorption R_d values are very similar for monosulfate, sulfide-AFm and hemicarbonate. A slightly higher uptake occurs by AFm phases with a singly charged anion in the interlayer (HS-AFm) as compared to AFm with divalent ions (monosulfate), whereas uptake by hemicarbonate is intermediate. No significant sorption occurs onto monocarbonate. Our derived thermodynamic solid solution models reproduce the experimentally obtained sorption isotherms on HS-AFm, hemicarbonate and monosulfate, indicating that anion exchange in the interlayer is the dominant mechanism and that the contribution of I^- electrostatic surface sorption to the overall uptake is negligible.

The regression detectability index RDI for mammography images of breast phantoms with calcification-like objects and anatomical background

Currently, quality assurance measurements in mammography are performed on unprocessed images. For diagnosis, however, radiologists are provided with processed images. This image processing is optimised for images of human anatomy and therefore does not always perform satisfactorily with technical phantoms. To overcome this problem, it may be possible to use anthropomorphic phantoms reflecting the anatomic structure of the human breast in place of technical phantoms when carrying out task-specific quality assessment using model observers. However, the use of model observers is hampered by the fact that a large number of images needs to be acquired. A recently published novel observer called the regression detectability index (RDI) needs significantly fewer images, but requires the background of the images to be flat. Therefore, to be able to apply the RDI to images of anthropomorphic phantoms, the anatomic background needs to be removed. For this, a procedure in which the anatomical structures are fitted by thin plate spline (TPS) interpolation has been developed. When the object to be detected is small, such as a calcification-like lesion, it is shown that the anatomic background can be removed successfully by subtracting the TPS interpolation, which makes the background-free image accessible to the RDI. We have compared the detectability obtained by the RDI with TPS background subtraction to results of the channelized Hotelling observer (CHO) and human observers. With the RDI, results for the detectabilityd'can be obtained using 75% fewer images compared to the CHO, while the same uncertainty ofd'is achieved. Furthermore, the correlation ofd'(RDI) with the results of human observers is at least as good as that ofd'(CHO) with human observers.

Development of physical fitness performance in young Swiss men from 2006 to 2015

From 1980 to 2000, physical fitness decreased and body mass index (BMI) increased in the population of many industrialized countries. Little is known about these trends after the year 2000. This study aimed to investigate physical fitness performance, physical activity (PA) behavior, and BMI of young, male Swiss adults between 2006 and 2015. For this purpose, results from the Swiss Armed Forces mandatory recruitment were used. A total of 306 746 male conscripts provided complete fitness test data, mean ± SD (range from 5th to 95th percentile): 20 ± 1 (18‐21) years, 178 ± 7 (168‐189) cm; 74 ± 13 (58‐97) kg, predicted maximal oxygen consumption of 49.9 ± 4.6 (41.8‐56.9) mL/kg/min (Conconi test), 125 ± 58 (43‐232) seconds in trunk muscle strength test (prone bridge), 2.31 ± 0.24 (1.90‐2.66) m in standing long jump, 6.46 ± 0.73 (5.30‐7.70) m in seated shot put (2 kg medical‐ball shot) and 45.6 ± 12.2 (29.9‐66.7) seconds in one‐leg standing test (sum of both legs; eyes closed after 10 seconds and head tilted back after 20 seconds). In the investigated population, 73.8% fulfilled basic PA recommendations, 46.2% were classified as regularly vigorously active. Performances in aerobic endurance and muscle power did not show secular changes over time. However, core stability performance and PA behavior increased, while balance ability decreased over this 10‐year period. Average BMI increased by 2.0% between 2006 and 2010 and did not change thereafter. Male Swiss adults are at least as physically fit as they were a decade ago. The secular trends of decreasing physical performances and increasing BMI have stopped, and self‐reported sport participation and leisure time PA have been increased in the observed population over the last 10 years.

Transport of low molecular weight organic compounds in compacted illite and kaolinite

¹⁴C-containing dissolved organic compounds may significantly contribute to the calculated annual overall dose emanated from a deep geological repository for radioactive waste. To date, there is a general lack of knowledge concerning the transport behaviour of low molecular weight organic compounds in the geosphere. The present work is aiming at a generic approach to measure weak adsorption of such compounds onto selected clay minerals. Percolation experiments were employed to sensitively measure the retardation of low molecular weight carboxylates and alcohols in compacted illite and kaolinite as a function of the ionic strength. Detection limits of ∼10^-5 m³ kg^-1 for the involved sorption distribution coefficients were attained thereby. The adsorption of alcohols on clays was near the detection limit and assumed to occur predominately via H-bonding. The adsorption of organic anions was influenced by several factors such as molecular structure, type of clay surfaces and the chemical composition of the aqueous phase. It was found that the relative position of neighbouring hydroxyl groups strongly influenced the retardation behaviour. Alpha-hydroxylated carboxylates, such as lactate, were found to be most retarded. Ligand exchange at the edge aluminol sites is the most probable explanation for the uptake of the negatively charged organic test compounds by the clay surface. The breakthrough behaviour of organic anions was additionally impacted by anion exclusion in illite. The demonstrated weak retardation of the test compounds can be robustly introduced in transport models, leading thus to a much lower contribution of ¹⁴C to the expected long-term overall dose.

Incidence of the Familial Non-medullary Thyroid Carcinoma in the Patient Register of the Clinic and Policlinic of Nuclear Medicine, University of Würzburg

Aim: In this study the incidence rate of familial nonmedullary thyroid carcinoma was investigated in the first and second grade relatives of patients registered at the Clinic and Policlinic for Nuclear Medicine, University of Würzburg. Patients and Methods: In this study 596 patients with differentiated thyroid carcinoma were enclosed, who were treated between 01.01.81 and 31.12.95. The data concerning a familial occurrence were studied by a retrospective survey-based analysis. These data were compared to a literature analysis for familial non-meduilary thyroid carcinoma. Results: 14 patients of the 596 patients treated showed a familial occurrence (2,3%). All these patients suffered from papillary thyroid carcinoma. According to the prognostic factors (tumor state, lymph node involvement, metastastic disease) no differences could be evaluated in the different groups (sporadic versus familial non-medullary thyroid disease). Conclusion: A familial occurrence of differentiated thyroid carcinomas is not frequently observed, but should be considered due to further genetic diseases.

Intra- and interobserver variability of thyroid volume measurements in healthy adults by 2D versus 3D ultrasound

Thyroid volume measurement by ultrasonography (US) is essential in numerous clinical diagnostic and therapeutic fields. While known to be limited, the accuracy and precision of two-dimensional (2D) US thyroid volume measurement have not been thoroughly characterized. Objective: We sought to assess the intra- and interobserver variability, accuracy and precision of thyroid volume determination by conventional 2D US in healthy adults using reference volumes determined by three-dimensional (3D) US. Design, methods: In a prospective blinded trial, thyroid volumes of ten volunteers were determined repeatedly by nine experienced sonographers using conventional 2D US (ellipsoid model). The values obtained were statistically compared to the so-called true volumes determined by 3D US (multiplanar approximation), the so-called gold standard, to estimate systematic errors and relative deviations of individual observers. Results: The standard error of measurement (SEM) for one observer and successive measurements (intraobserver variability), was 14%, and for different observers and repeated measurements (interobserver variability), 17%. The minimum relative thyroid volume change significantly different at the 95% level was 39% for the same observer and 46% for different observers. Regarding accuracy, the mean value of the differences showed a significant thyroid volume overestimation (17%, p <0.01) by 2D relative to 3D US. Conclusion: 2D US is appropriate for routine thyroid volumetry. Nevertheless, the so-called human factor (random error) should be kept in mind and correction is needed for methodical bias (systematic error). Further efforts are required to improve the accuracy and precision of 2D US thyroid volumetry by optimizing the underlying geometrical modeling or by the application of 3D US.

Adapted marching distances and physical training decrease recruits' injuries and attrition

There is evidence that progressive loading of physical demands at the beginning of basic military service and specific physical training can reduce injury incidences. Therefore, aim of this study was to measure the effects of a progressive increase in marching distances and an adapted physical training program on injury incidence and attrition rate in a Swiss Army infantry training school. One company reduced the distances covered on foot during the first 4 weeks of basic military training. A second company performed an adapted physical training program for 10 weeks. A third company participated in both interventions combined, and a fourth company served as a control group without any intervention. The injury incidences and attrition rates of 651 male recruits were registered during 21 weeks of military service. Several predictor variables for injury and attrition, such as physical fitness, previous injuries, level of previous physical activity, smoking, motivation, and socioeconomic factors, were assessed as well. The data were analyzed using binary logistic backward regressions. Each intervention separately had a favorable effect on injury prevention. However, combining the 2 interventions resulted in the greatest reduction in injury incidence rate (-33%). Furthermore, the adapted physical training successfully reduced the military service attrition rates (-53%).

Training Methods and Training Instructors' Qualification Are Related to Recruits' Fitness Development During Basic Military Training

Adequate physical fitness is essential for successful military service. Military organizations worldwide therefore make continuous efforts to improve their army's physical training (PT) programs. To investigate the effect of the training methods and the qualification of PT instructors on the development of recruits' physical fitness, the present study compared the outcomes of 2 training groups. Both study groups participated in approximately 145 minutes per week of PT. The control group executed the standard army PT prepared and supervised by army PT instructors. Content of the PT in the intervention group was similar to that of the control group, but their training sessions' methods were different. Their training sessions were organized, prepared, and delivered by more and better-qualified supervisors (tertiary-educated physical education teachers). After 10 weeks of training, the participants of the intervention group experienced a significantly greater physical fitness improvement than those of the control group (positive change in endurance 32 and 17%, balance 30 and 21%, and core strength 74 and 45%, respectively). In both groups, the recruits with the lowest initial fitness levels significantly increased their performance. In the intervention group, but not the control, one-third of the recruits with the highest initial fitness levels were able to further improve their general fitness performance. This study demonstrates that the training methods and quality of instruction during PT sessions are relevant for recruits' fitness development in basic military training.

Dissolution-precipitation processes in tank experiments for testing numerical models for reactive transport calculations: Experiments and modelling

In the context of testing reactive transport codes and their underlying conceptual models, a simple 2D reactive transport experiment was developed. The aim was to use simple chemistry and design a reproducible and fast to conduct experiment, which is flexible enough to include several process couplings: advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. A small tank was filled with a reactive layer of strontium sulfate (SrSO4) of two different grain sizes, sandwiched between two layers of essentially non-reacting quartz sand (SiO2). A highly concentrated solution of barium chloride was injected to create an asymmetric flow field. Once the barium chloride reached the reactive layer, it forced the transformation of strontium sulfate into barium sulfate (BaSO4). Due to the higher molar volume of barium sulfate, its precipitation caused a decrease of porosity and lowered the permeability. Changes in the flow field were observed with help of dye tracer tests. The experiments were modelled using the reactive transport code OpenGeosys-GEM. Tests with non-reactive tracers performed prior to barium chloride injection, as well as the density-driven flow (due to the high concentration of barium chloride solution), could be well reproduced by the numerical model. To reproduce the mineral bulk transformation with time, two populations of strontium sulfate grains with different kinetic rates of dissolution were applied. However, a default porosity permeability relationship was unable to account for measured pressure changes. Post mortem analysis of the strontium sulfate reactive medium provided useful information on the chemical and structural changes occurring at the pore scale at the interface that were considered in our model to reproduce the pressure evolution with time.

Regional differences of physical activity and sedentary behaviour in Swiss children are not explained by socio-demographics or the built environment

OBJECTIVE

We evaluated whether regional differences in physical activity (PA) and sedentary behaviour (SB) existed along language boundaries within Switzerland and whether potential differences would be explained by socio-demographics or environmental characteristics.

METHODS

We combined data of 611 children aged 4 to 7 years from four regional studies. PA and SB were assessed by accelerometers. Information about the socio-demographic background was obtained by questionnaires. Objective neighbourhood attributes could be linked to home addresses. Multivariate regression models were used to test associations between PA and SB and socio-demographic characteristics and neighbourhood attributes.

RESULTS

Children from the German compared to the French-speaking region were more physically active and less sedentary (by 10-15 %, p < 0.01). Although German-speaking children lived in a more favourable environment and a higher socioeconomic neighbourhood (differences p < 0.001), these characteristics did not explain the differences in PA behaviour between French and German speaking.

CONCLUSIONS

Factors related to the language region, which might be culturally rooted were among the strongest correlates of PA and SB among Swiss children, independent of individual, social and environmental factors.

Reactivity to accelerometer measurement of children and adolescents

Supplemental digital content is available in the text.

Purpose

Awareness of being monitored can influence participants’ habitual physical activity (PA) behavior. This reactivity effect may threaten the validity of PA assessment. Reports on reactivity when measuring the PA of children and adolescents have been inconsistent. The aim of this study was to investigate whether PA outcomes measured by accelerometer devices differ from measurement day to measurement day and whether the day of the week and the day on which measurement started influence these differences.

Methods

Accelerometer data (counts per minute [cpm]) of children and adolescents (n = 2081) pooled from eight studies in Switzerland with at least 10 h of daily valid recording were investigated for effects of measurement day, day of the week, and start day using mixed linear regression.

Results

The first measurement day was the most active day. Counts per minute were significantly higher than on the second to the sixth day, but not on the seventh day. Differences in the age-adjusted means between the first and consecutive days ranged from 23 to 45 cpm (3.6%–7.1%). In preschoolchildren, the differences almost reached 10%. The start day significantly influenced PA outcome measures.

Conclusions

Reactivity to accelerometer measurement of PA is likely to be present to an extent of approximately 5% on the first day and may introduce a relevant bias to accelerometer-based studies. In preschoolchildren, the effects are larger than those in elementary and secondary schoolchildren. As the day of the week and the start day significantly influence PA estimates, researchers should plan for at least one familiarization day in school-age children and randomly assign start days.

The thyroid axis 'setpoints' are significantly altered after long-term suppressive LT4 therapy

The aim of the study was to investigate the changes in the thyroid axis setpoint after long-term suppressive levothyroxine therapy for differentiated thyroid carcinoma and the resulting changes in levothyroxine requirement. Ninety-nine differentiated thyroid cancer patients were reviewed. All patients had at least one known TSH-level≥0.01 mU/l (lower detection limit) and <1.0 mU/l within 2 years of initial treatment (time 1) and had at least one TSH-value≥0.01 mU/l and <1.0 mU/l after continuous LT4 therapy for a minimum of 5 years (time 2).At time 2 the mean LT4 dosage/kg body weight, TSH, FT3, and FT4 levels were significantly lower than at time 1, while body weight was higher. At time 2, the FT3/FT4 ratio rate had dropped significantly (p<0.001). At time 1, patients would require 2.96 μg/kg body weight to reach total TSH suppression. The dose of levothyroxine/kg required for suppression can be lowered by about 0.05 μg/kg body weight for each year of suppressive therapy. After a median of 12.7 years of continuous suppressive levothyroxine therapy, patients would require 2.25 μg/kg body weight (-23.5%) to reach total TSH-suppression. At least part of this reduction was independent of aging. As a result of changes in thyroid hormone metabolism and thyroid axis setpoint, long-term TSH-suppressive therapy contributes to a reduction in the dosage of levothyroxine per kilogram body weight required for full TSH suppression over time.

Relationship between the objectively-assessed neighborhood area and activity behavior in Swiss youth

Background

Neighborhood attributes are modifiable determinants of physical activity (PA) and sedentary behavior (SB). We tested whether the objectively-assessed built and social environment was associated with PA and SB in Swiss youth and whether sex, age and the socioeconomic position (Swiss-SEP) modified such associations.

Methods

We combined data of 1742 youth (ages 4 to 17) from seven studies conducted within Switzerland between 2005–2010. All youth provided accelerometer data and a home address, which was linked to objective environmental data and the Swiss-SEP-index. Associations between neighborhood attributes and PA were analyzed by multivariable multilevel regression analyses.

Results

The extent of green areas and building density was positively associated with PA in the total sample (p < 0.05). Factors representing centrally located areas, and more schoolchildren living nearby tended to increase PA in secondary schoolchildren, boys and those from lower-ranked socioeconomic areas. In primary schoolchildren, the extent of green areas was positively associated with PA (p = 0.05). Associations between neighborhood attributes and PA were more pronounced in youth from low socioeconomic areas.

Conclusions

The results indicate that some associations between neighborhood attributes and PA differ by age, sex and socioeconomic area. This should be taken into account when planning interventions to increase childhood PA.

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Comprehensive assessment of objectively measured neighborhood attributes in Europe

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Effects of neighborhood attributes on PA differed by age-group, sex and socioeconomic neighborhood.

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Associations between neighborhood attributes and PA were more pronounced in youth from low socioeconomic areas.

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Strongest associations with green spaces and centrally located areas

A low-cost X-ray-transparent experimental cell for synchrotron-based X-ray microtomography studies under geological reservoir conditions

A new modular X-ray-transparent experimental cell enables tomographic investigations of fluid rock interaction under natural reservoir conditions (confining pressure up to 20 MPa, pore fluid pressure up to 15 MPa, temperature ranging from 296 to 473 K). The portable cell can be used at synchrotron radiation sources that deliver a minimum X-ray flux density of 10(9) photons mm(-2) s(-1) in the energy range 30-100 keV to acquire tomographic datasets in less than 60 s. It has been successfully used in three experiments at the bending-magnet beamline 2BM at the Advanced Photon Source. The cell can be easily machined and assembled from off-the-shelf components at relatively low costs, and its modular design allows it to be adapted to a wide range of experiments and lower-energy X-ray sources.

Neural network versus activity-specific prediction equations for energy expenditure estimation in children

The aim of this study was to compare the energy expenditure (EE) estimations of activity-specific prediction equations (ASPE) and of an artificial neural network (ANNEE) based on accelerometry with measured EE. Forty-three children (age: 9.8 ± 2.4 yr) performed eight different activities. They were equipped with one tri-axial accelerometer that collected data in 1-s epochs and a portable gas analyzer. The ASPE and the ANNEE were trained to estimate the EE by including accelerometry, age, gender, and weight of the participants. To provide the activity-specific information, a decision tree was trained to recognize the type of activity through accelerometer data. The ASPE were applied to the activity-type-specific data recognized by the tree (Tree-ASPE). The Tree-ASPE precisely estimated the EE of all activities except cycling [bias: −1.13 ± 1.33 metabolic equivalent (MET)] and walking (bias: 0.29 ± 0.64 MET; P < 0.05). The ANNEE overestimated the EE of stationary activities (bias: 0.31 ± 0.47 MET) and walking (bias: 0.61 ± 0.72 MET) and underestimated the EE of cycling (bias: −0.90 ± 1.18 MET; P < 0.05). Biases of EE in stationary activities (ANNEE: 0.31 ± 0.47 MET, Tree-ASPE: 0.08 ± 0.21 MET) and walking (ANNEE 0.61 ± 0.72 MET, Tree-ASPE: 0.29 ± 0.64 MET) were significantly smaller in the Tree-ASPE than in the ANNEE ( P < 0.05). The Tree-ASPE was more precise in estimating the EE than the ANNEE. The use of activity-type-specific information for subsequent EE prediction equations might be a promising approach for future studies.

Differences in weight status and energy-balance related behaviors among schoolchildren in German-speaking Switzerland compared to seven countries in Europe

Background

Overweight in children and adolescents have increased significantly and are a major public health problem. To allow international comparisons, Switzerland joined the European study ‘ENERGY’ cross sectional survey consortium that investigated the prevalence of overweight and obesity as well as selected dietary, physical and sedentary behaviors of 10–12 years old pupils across seven other countries in Europe. The aims of the present study was to compare body composition and energy-balance related behaviors of Swiss schoolchildren to those of the seven European ENERGY-countries and to analyze overweight and energy-balance related behaviors of Swiss children according to socio-demographic factors.

Methods

A school-based cross-sectional study among 10–12 year old children was conducted in Switzerland and seven other European countries using a standardized protocol. Body height, weight and waist-circumference were measured by trained research assistants. Energy-balance related behaviors –i.e. selected dietary, physical activity and screen-viewing behaviors were assessed by questionnaires. Weight status and behaviors in Switzerland were compared to the seven European ENERGY countries. Within the Swiss sample, analyses stratified by gender, parental education and ethnicity were performed.

Results

Data of 546 Swiss children (mean age 11.6±0.8y, 48% girls) were obtained and compared to the ENERGY- results (N=7.148; mean age 11.5±0.8y, 48% girls). In Switzerland significantly less children were overweight (13.9%) or obese (2.3%) compared to the average across the ENERGY-countries (23.7% and 4.7%, respectively), and were even somewhat lower than the ENERGY countries with the lowest prevalence. Sugar sweetened beverage intakes and breakfast habits of Swiss children did not differ significantly from those of ENERGY. However, the mean time devoted by Swiss children to walking or cycling to school and attending sports activities was significantly higher and screen time significantly lower compared to the other ENERGY-countries. Within the Swiss, sample relatively large and consistent differences were observed between children from native and non-native ethnicity.

Conclusions

The prevalence of overweight and obesity among Swiss children are substantial but significantly lower compared to all other European ENERGY-Partners, probably due to the fact that Swiss children were found to be more active and less sedentary comparing to the rest of the European sample.

The Swiss Army physical fitness test battery predicts risk of overuse injuries among recruits

AIM

The aim of this study was to quantify the discriminative power of physical performance tests to recognize conscripts with enhanced risk of acute and overuse injuries in specific, physically demanding occupational specialties of the Swiss Army. The five performance tests investigated represent the Swiss Army Physical Fitness Test Battery.

METHODS

Physical fitness performances were assessed during recruitment procedures prior to military service, and injury occurrences were assessed during 18 weeks of boot camp. Complete fitness and injury data of 459 volunteers from four military occupational specialties were collected. Discriminative power of volunteers' aerobic endurance capacity, trunk muscle fitness, muscle power of upper and lower extremities, and balance for predicting risk of acute injuries and for predicting risk of overuse injuries was calculated using receiver operating characteristic curve analysis.

RESULTS

The presented fitness tests had no discriminative power for predicting the risk of acute injuries. However, the trunk muscle fitness test was discriminative in predicting overuse injuries in all four military occupational specialties, progressive endurance run in three, balance test in two, and standing long jump in one. Only the seated shot put had no significant power for predicting overuse injuries in all four study groups. However, for different occupational specialties, different fitness parameters were discriminative to predict overuse injuries.

CONCLUSION

It is possible to conclude that the fitness tests used allow detection of conscripts with enhanced overuse injury risk in physically demanding occupational specialties and therefore provide an indicator to select suitable personnel for physically demanding jobs in a military organization.

Assessing the Cr(VI) reduction efficiency of a permeable reactive barrier using Cr isotope measurements and 2D reactive transport modeling

In Thun, Switzerland, a permeable reactive barrier (PRB) for Cr(VI) reduction by gray cast iron was installed in May 2008. The PRB is composed of a double array of vertical piles containing iron shavings and gravel. The aquifer in Thun is almost saturated with dissolved oxygen and the groundwater flow velocities are ca. 10-15m/day. Two years after PRB installation Cr(VI) concentrations still permanently exceed the Swiss threshold value for contaminated sites downstream of the barrier at selected localities. Groundwater δ(53/52)Cr(SRM979) measurements were used to track Cr(VI) reduction induced by the PRB. δ(53/52)Cr(SRM979) values of two samples downstream of the PRB showed a clear fractionation towards more positive values compared to four samples from the hotspot, which is clear evidence of Cr(VI) reduction induced by the PRB. Another downstream sample did not show a shift to more positive δ(53/52)Cr(SRM979) values. Because this latter location correlates with the highest downstream Cr(VI) concentration it is proposed that a part of the Cr(VI) plume is bypassing the barrier. Using a Rayleigh fractionation model a minimum present-day overall Cr(VI) reduction efficiency of ca. 15% was estimated. A series of 2D model simulations, including the fractionation of Cr isotopes, confirm that only a PRB bypass of parts of the Cr(VI) plume can lead to the observed values. Additionally, the simulations revealed that the proposed bypass occurs due to an insufficient permeability of the individual PRB piles. It is concluded that with this type of PRB a complete and long-lasting Cr(VI) reduction is extremely difficult to achieve for Cr(VI) contaminations located in nearly oxygen and calcium carbonate saturated aquifer in a regime of high groundwater velocities. Additional remediation action would limit the environmental impact and allow to reach target concentrations.

Built environment, parents' perception, and children's vigorous outdoor play

OBJECTIVES

To evaluate the combined effects and relative importance of socio-cultural factors as well as parents' subjectively perceived and objectively assessed environment on time children spent vigorously playing outdoors.

METHODS

Cross-sectional study conducted in Berne, Biel-Bienne, and Payerne (Switzerland) during the school year 2004/2005. Included 1345 parental questionnaires from children out of three age groups (6/7, 9/10, and 13/14 years). A total of 1081 (80%) provided a home address, which could be linked to environmental data using a geographic information system (GIS).

RESULTS

GIS-derived main street density in a buffer of 100 m around the home was inversely associated with time playing outdoors in adolescents and younger children, but only in more urbanized areas. In addition and independently of GIS-based main street density, parental concern about traffic safety was associated with less time playing outdoors in primary school children. Girls, adolescents, and children from the French speaking part of the country spent less time playing outdoors. A non-Swiss nationality and having younger siblings increased time playing vigorously outdoors in adolescents.

CONCLUSION

In addition to socio-cultural factors, parents' perceptions and objectively measured environmental factors were significantly associated with the time spent vigorously playing outdoors. These associations differed by age group.

Assessment of long-term performance and chromate reduction mechanisms in a field scale permeable reactive barrier

An innovative full-scale implementation of a permeable reactive barrier, consisting of a double-row of cylinders filled with zerovalent iron shavings, for chromate remediation was monitored over four years. Solid samples were analyzed to elucidate (i) the relevant corrosion mechanisms and products, (ii) the pathways of chromate reduction and immobilization, and (iii) the long-term performance of the barrier situated in a hydrological and geochemical complex groundwater regime. Sampling and analysis of groundwater and reactive material revealed an oxidative iron corrosion zone evolving in the inflow and a zone of anaerobic iron corrosion in the center and outflow of the barrier. Chromate reduction was mainly confined to the inflow region. The formation and thickness of corrosion rinds depended on sampling time, position, and depth, as well as on the size, shape, and graphite content In the inflow, the corrosion rinds mostly consisted of goethite and ferrihydrite. X-ray absorption fine structure spectroscopy revealed two distinct Cr(III) species, most likely resulting from homogeneous and heterogeneous redox reaction pathways, respectively. The longevity and long-term effectiveness of the PRB appears to be primarily limited by reduced corrosion rates of the ZVI-shavings because of the thick layers of Fe-hydroxides.

Assessment of intensity, prevalence and duration of everyday activities in Swiss school children: a cross-sectional analysis of accelerometer and diary data

Background

Appropriately measuring habitual physical activity (PA) in children is a major challenge. Questionnaires and accelerometers are the most widely used instruments but both have well-known limitations. The aims of this study were to determine activity type/mode and to quantify intensity and duration of children's everyday PA by combining information of a time activity diary with accelerometer measurements and to assess differences by gender and age.

Methods

School children (n = 189) aged 6/7 years, 9/10 years and 13/14 years wore accelerometers during one week in winter 2004 and one in summer 2005. Simultaneously, they completed a newly developed time-activity diary during 4 days per week recording different activities performed during each 15 min interval. For each specific activity, the mean intensity (accelerometer counts/min), mean duration per day (min/d) and proportion of involved children were calculated using linear regression models.

Results

For the full range of activities, boys accumulated more mean counts/min than girls. Adolescents spent more time in high intensity sports activities than younger children (p < 0.001) but this increase was compensated by a reduction in time spent playing vigorously (p = 0.04). In addition, adolescents spent significantly more time in sedentary activities (p < 0.001) and accumulated less counts/min during these activities than younger children (p = 0.007). Among moderate to vigorous activities, children spent most time with vigorous play (43 min/day) and active transportation (56 min/day).

Conclusion

The combination of accelerometers and time activity diaries provides insight into age and gender related differences in PA. This information is warranted to efficiently guide and evaluate PA promotion.

[Ten years of epidemiological cancer registration in Bavaria]

For a large territorial state like Bavaria only a decentralised cancer registration structure promises successful results: in the form of regional clinical cancer registries and--using the clinical registration as a base--one population-based registry. After ten years of epidemiological cancer registration in Bavaria it can now be shown that the chosen registration concept has proved itself. Currently the completeness of cancer notifications exceeded the international recommended threshold of 90%. A largely complete data stock is available for the years of diagnosis from 2004 to 2005. The task sharing between clinical and population-based cancer registries avoids double registration of data. Both types of registries are supporting physicians and hospitals with a wide palette of services. Together they enable transparency of cancer occurrence as well as transparency of health care for tumour patients.

Personal and environmental factors associated with active commuting to school in Switzerland

OBJECTIVE

To assess whether prevalence of active commuting and regular car trips to school varies across communities and language regions in Switzerland and to determine personal and environmental correlates.

METHODS

During the school year 2004/2005, 1345 parental questionnaires (response rate 65%) of children attending 1st, 4th and 8th grades were completed, 1031 could be linked to a GIS environmental database. A German-speaking, a French-speaking and a bilingual study area were included. Usual mode of transportation and frequency of regular car trips to school were assessed. Associations with personal and environmental factors were evaluated with multivariate regression models.

RESULTS

Seventy-eight percent of the children actively traveled to school. Twelve percent were regularly driven at least once a week by car. Major road crossings and distance were significantly related to usual mode of transportation, but not to regular car trips. Age, daycare attendance, parental safety concerns, number of cars in the household and belonging to French-speaking population were significantly associated with increased regular car trips.

CONCLUSION

Objective predictors are main deciding factors for active commuting to school as main mode of transport whereas personal and lifestyle factors are important factors associated with frequency of car use. Not only objective but also differing cultural attitudes should be considered when promoting non-motorized travel.

Detailed mapping of chromosome 17p deletions reveals HIC1 as a novel tumor suppressor gene candidate telomeric to TP53 in diffuse large B-cell lymphoma

Deletions in the short arm of chromosome 17 (17p) involving the tumor suppressor TP53 occur in up to 20% of diffuse large B-cell lymphomas (DLBCLs). Although inactivation of both alleles of a tumor suppressor gene is usually required for tumor development, the overlap between TP53 deletions and mutations is poorly understood in DLBCLs, suggesting the possible existence of additional tumor suppressor genes in 17p. Using a bacterial artificial chromosome (BAC) and Phage 1 artificial chromosome (PAC) contig, we here define a minimally deleted region in DLBCLs encompassing approximately 0.8 MB telomeric to the TP53 locus. This genomic region harbors the tumor suppressor Hypermethylated in Cancer 1 (HIC1). Methylation-specific PCR demonstrated hypermethylation of HIC1 exon 1a in a substantial subset of DLBCLs, which is accompanied by simultaneous HIC1 deletion of the second allele in 90% of cases. In contrast, HIC1 inactivation by hypermethylation was rarely encountered in DLBCLs without concomitant loss of the second allele. DLBCL patients with complete inactivation of both HIC1 and TP53 may be characterized by an even inferior clinical course than patients with inactivation of TP53 alone, suggesting a functional cooperation between these two proteins. These findings strongly imply HIC1 as a novel tumor suppressor in a subset of DLBCLs.

Intra- and interobserver variability of thyroid volume measurements in healthy adults by 2D versus 3D ultrasound

Thyroid volume measurement by ultrasonography (US) is essential in numerous clinical diagnostic and therapeutic fields. While known to be limited, the accuracy and precision of two-dimensional (2D) US thyroid volume measurement have not been thoroughly characterized.

OBJECTIVE

We sought to assess the intra- and interobserver variability, accuracy and precision of thyroid volume determination by conventional 2D US in healthy adults using reference volumes determined by three-dimensional (3D) US. Design,

METHODS

In a prospective blinded trial, thyroid volumes of ten volunteers were determined repeatedly by nine experienced sonographers using conventional 2D US (ellipsoid model). The values obtained were statistically compared to the so-called true volumes determined by 3D US (multiplanar approximation), the so-called gold standard, to estimate systematic errors and relative deviations of individual observers.

RESULTS

The standard error of measurement (SEM) for one observer and successive measurements (intraobserver variability), was 14%, and for different observers and repeated measurements (interobserver variability), 17%. The minimum relative thyroid volume change significantly different at the 95% level was 39% for the same observer and 46% for different observers. Regarding accuracy, the mean value of the differences showed a significant thyroid volume overestimation (17%, p < 0.01) by 2D relative to 3D US.

CONCLUSION

2D US is appropriate for routine thyroid volumetry. Nevertheless, the so-called human factor (random error) should be kept in mind and correction is needed for methodical bias (systematic error). Further efforts are required to improve the accuracy and precision of 2D US thyroid volumetry by optimizing the underlying geometrical modeling or by the application of 3D US.

Validity of Four Short Physical Activity Questionnaires in Middle-Aged Persons

PURPOSE

Self-administered questionnaires continue to be the most widely used type of physical activity assessment in epidemiological studies. However, test-retest reliability and validity of physical activity questionnaires have to be determined. In this study, three short physical activity questionnaires already used in Switzerland and the International Physical Activity Questionnaire (IPAQ) were validated.

METHODS

Test-retest reliability was assessed by repeated administration of all questionnaires within 3 wk in 178 volunteers (77 women, 46.1+/-14.8 yr; 101 men 46.8+/-13.2 yr). Validity of categorical and continuous data was studied in a subsample of 35 persons in relation to 7-d accelerometer readings, percent body fat, and cardiorespiratory fitness.

RESULTS

Reliability was fair to good with a Spearman correlation coefficient range of 0.43-0.68 for measures of continuous data and moderate to fair with Kappa values between 0.32 and 0.46 for dichotomous measures active/inactive. Total physical activity reported in the IPAQ and the Office in Motion Questionnaire (OIMQ) correlated with accelerometry readings (r=0.39 and 0.44, respectively). In contrast, correlations of self-reported physical data with percent body fat and cardiorespiratory fitness were low (r=-0.26-0.29). Participants categorized as active by the Swiss HEPA Survey 1999 instrument (HEPA99) accumulated significantly more days of the recommended physical activities than their inactive counterparts (4.4 and 2.7 d.wk, respectively, P<0.05). However, compared with accelerometer data, vigorous physical activities were overreported in investigated questionnaires.

CONCLUSION

Collecting valid data on physical activity remains a challenging issue for questionnaire surveys. The IPAQ and the three other questionnaires are characterized to inform decisions about their appropriate use.

Cold induction of the Bacillus subtilis bkd operon is mediated by increased mRNA stability

Recently it has been demonstrated that the ptb - bcd - buk - lpdV - bkdAA - bkdAB - bkdB operon ( bkdoperon) of Bacillus subtilis, which encodes the enzymes that catalyze the degradation of branched-chain amino acids, is inducible by a temperature downshift from 37 to 18 degrees C. Deamination and oxidative decarboxylation of isoleucine generates 2-methyl-butyryl-CoA, which serves as the precursor of anteiso-branched fatty acid species. Most probably, the induction of this operon upon cold shock ensures an increase in the content of anteiso-branched fatty acids in the membrane lipids at low temperature, thus permitting maintenance of membrane fluidity at lower temperatures. In the present study, we have analyzed the mechanism of cold induction of the bkd operon and of four further cold-inducible transcriptional units in B. subtilis. We demonstrate that cold induction of these genes is mediated by an increase in the stability of the corresponding mRNAs. None of the promoters that control the five transcriptional units analyzed is actually cold-inducible. Furthermore, the results of this study indicate that the 5' leader regions are not involved in the cold-induced stabilization of the mRNAs. The structural elements that enhance mRNA stability must therefore be restricted to the 3'-ends and/or the coding regions.

Bacillus subtilis functional genomics: genome-wide analysis of the DegS-DegU regulon by transcriptomics and proteomics

The DegS-DegU two-component regulatory system of Bacillus subtilis controls various processes that characterize the transition from the exponential to the stationary growth phase, including the induction of extracellular degradative enzymes, expression of late competence genes and down-regulation of the sigma(D) regulon. The degU32(Hy) mutation stabilizes the phosphorylated form of DegU (DegU-P), resulting in overproduction of several extracellular degradative enzymes. In this study, the pleiotropic DegS-DegU regulon was characterized by combining proteomic and transcriptomic approaches. A comparative analysis of wild-type B. subtilis and the degU32(Hy) mutant grown in complex medium was performed during the exponential and in the stationary growth phase. Besides genes already known to be under the control of DegU-P, novel putative members of this regulon were identified. Although the degU32(Hy) mutant is assumed to contain high levels of phosphorylated DegU in the exponential as well as in the stationary growth phase, many genes known to be positively regulated by DegU-P did not show enhanced expression in the mutant strain during exponential growth. This is consistent with the fact that most genes belonging to the DegS-DegU regulon are subject to multiple regulation; this is also reflected in the strong stationary-phase induction of these genes in the mutant strain. As expected, during the exponential growth phase, the sigma(D) regulon was expressed at significantly lower levels in the degU32(Hy) mutant than in the wild type.

[Incidence and spectrum of malignant disease among dialysis patients in North Bavaria]

BACKGROUND AND OBJECTIVE

In end-stage renal failure the incidence of cancer is increased. With regard to frequency and pattern of distribution of the tumors, there are substantial regional differences. Since this topic has to date received only minimal attention in Germany, we undertook a multi-centric analysis (8 dialysis centres) in North Bavaria in order to address the occurrence of malignant diseases in end-stage renal failure.

PATIENTS AND METHODS

Of a total of 2228 patients, who underwent hemodialysis in the period from 1990 - 99 as a consequence of end-stage renal failure, the medical records of 1727 persons were analysed. Only those patients were considered, whose malignancy was diagnosed in the course of the dialysis. The Saarland cancer register served as a comparative age- and sex-matched population, with which we calculated the expected frequency of the various cancers as well as the standard incidence ratio (SIR) for the dialysis patients.

RESULTS

In total 125 malignant diseases were documented. The cancer incidence was highest in the first year of treatment and was clearly lower in the subsequent periods. Of great importance was the age of the patients. The highest SIR scores were found for patients of middle age (35 - 50 years). An enhanced risk for cancer of the kidney, bladder, prostate, liver, oral cavity and the pharynx and larynx, as well as of the lymphatic and hemopoetic systems was found, while there was no or only a slight increase in the frequency of carcinoma of the mammary gland, stomach, colon-sigma-rectum and bronchial systems.

CONCLUSION

The high incidence of cancer in end-stage renal failure should be given greater attention. Particularly in the high-risk group of younger dialysis patients, a regular screening - especially for tumors of the kidney, bladder and liver - appears justified.

A comprehensive two-dimensional map of cytosolic proteins of Bacillus subtilis

Proteomics relying on two-dimensional (2-D) gel electrophoresis of proteins followed by spot identification with mass spectrometry is an excellent experimental tool for physiological studies opening a new perspective for understanding overall cell physiology. This is the intriguing outcome of a method introduced by Klose and O'Farrell independently 25 years ago. Physiological proteomics requires a 2-D reference map on which most of the main proteins were identified. In this paper, we present such a reference map with more than 300 entries for Bacillus subtilis proteins with an isoelectric point (pI) between 4 and 7. The most abundant proteins of exponentially growing cells were compiled and shown to perform mainly housekeeping functions in glycolysis, tricarboxylic acid cycle (TCC), amino acid biosynthesis and translation as well as protein quality control. Furthermore, putative post-translational modifications were shown at a large scale, with 47 proteins in total forming more than one spot. In a few selected cases evidence for phosphorylation of these proteins is presented. The proteome analysis in the standard pI range was complemented by either stretching the most crowded regions in a narrow pH gradient 4.5-5.5, or by adding other fractions of the total B. subtilis proteome such as alkaline proteins as well as extracellular proteins. A big challenge for future studies is to provide an experimental protocol covering the fraction of intrinsic membrane proteins that almost totally escaped detection by the experimental procedure used in this study.

Influence of continuous and discontinuous training protocols on subcutaneous adipose tissue and plasma substrates

It has been shown that bouts of high-intensity exercise may reduce subcutaneous adipose tissue more than low-intensity exercise. The aim of the present study was to examine if a discontinuous training protocol is more successful in reducing adipose tissue than a continuous endurance training protocol. Fourteen untrained male volunteers were divided into two groups and trained for 10 weeks performing 3 discontinuous or 3 continuous workouts weekly (discontinuous exercise: 25 times 80 s 35% VO2max and 40 s 80% VO2max; continuous exercise: 50 min 50% VO2max). The discontinuous and the continuous training resulted in a similar subcutaneous adipose tissue loss, determined by skinfold measurement, in the leg above the patella (-2.4+/-2.4 and -2.4+/-1.4mm, respectively). The normalised plasma concentrations of free fatty acid, glycerol, beta-hydroxybutyrate, and lactate were similar throughout the final exercise test at the end of the training period. Our data suggested that the discontinuous protocol, selected so that the average intensity was similar to that of the continuous protocol, was not better than the latter in reducing subcutaneous adipose tissue.

[Incidence of familial non-medullary thyroid carcinoma in the patient register of the Clinic and Polyclinic of Nuclear Medicine, University of Würzburg]

AIM

In this study the incidence rate of familial non-medullary thyroid carcinoma was investigated in the first and second grade relatives of patients registered at the Clinic and Polyclinic for Nuclear Medicine, University of Würzburg.

PATIENTS AND METHODS

In this study 596 patients with differentiated thyroid carcinoma were enclosed, who were treated between 01.01.81 and 31.12.95. The data concerning a familial occurrence were studied by a retrospective survey-based analysis. These data were compared to a literature analysis for familial non-medullary thyroid carcinoma.

RESULTS

14 patients of the 596 patients treated showed a familial occurrence (2.3%). All these patients suffered from papillary thyroid carcinoma. According to the prognostic factors (tumor state, lymph node involvement, metastatic disease) no differences could be evaluated in the different groups (sporadic versus familial non-medullary thyroid disease).

CONCLUSION

A familial occurrence of differentiated thyroid carcinomas is not frequently observed, but should be considered due to further genetic diseases.

Differentiated thyroid cancer in children and adolescents

INTRODUCTION

There have been only a few studies on differentiated childhood thyroid cancer (DTC) in children and adolescents.

METHODS

We analyzed the characteristics of DTC with respect to age, gender and histology in 114 patients under 18 years of age. In a questionnaire-based survey, data of 114 patients, aged between 3 years and 18 years, was collected from 65 clinical institutions in Germany. Characteristics of 80 females and 34 males were evaluated, and the prognostic effect of age, gender, histology, multicentric growth, tumor stage and N-status on distant metastases was tested using multivariate discriminant analysis. Between-group comparison was performed using student t-test and chi-squared test.

RESULTS

The incidence of DTC in females was higher than in males with a peak of female:male ratio at puberty, which was more pronounced in children with papillary thyroid cancer, but not with follicular thyroid cancer. Papillary thyroid cancer was associated with more advanced disease (P=0.009), more lymph-node involvement (P=0.007) and more distant metastases (P=0.02) compared with follicular thyroid cancer. Multivariate analysis showed advanced tumor stage as the only significant factor (P=0.02) associating with distant metastasis.

CONCLUSION

It can be concluded that in children and adolescents: 1. The incidence of papillary thyroid cancer is higher in females than males, with a peak at puberty. 2. The only significant factor associated with distant metastases is the advanced tumor stage. 3. Childhood thyroid cancer is frequently associated with lymph-node involvement, distant metastases and advanced tumor stage. 4. Papillary childhood thyroid cancer is more aggressive than follicular type.

Characteristics of differentiated thyroid carcinoma in children and adolescents with respect to age, gender, and histology

BACKGROUND

Because of its rarity there have been only a few detailed studies on differentiated thyroid carcinoma (DTC) in children. The current investigation was undertaken to assess the characteristics of DTC with respect to age, gender, and histology in children and adolescents.

METHODS

In a questionnaire-based survey, data from 114 children and adolescents with DTC (age range, 3-18 years) was collected from 65 clinical institutions in Germany. Characteristics of 80 females and 34 males were evaluated and the influence of age, gender, histology, multicentric growth, tumor stage, and lymph node involvement on distant metastases was tested using multivariate discriminant analysis. Comparison between groups was performed using the Student's t test and chi-square test. Correlation between incidence and age was assessed by linear regression analysis.

RESULTS

The overall incidence of thyroid carcinoma in females was higher than in males, with a peak of female/male ratio occurring at puberty. The incidence of DTC correlated with age in females < 16 years (correlation coefficient [r] = 0.84; P = 0.0006), which was more pronounced in children with papillary thyroid carcinoma (PTC) (r = 0.83; P = 0.006) but not in those with follicular thyroid carcinoma (FTC) (r = 0.20; P = 0.16). FTC was associated with less advanced disease (P = 0.009), fewer lymph nodes involved (P = 0.007), and fewer metastases (P = 0.02) compared with PTC. Males tended to have a higher risk for distant metastases. However, statistical analysis failed to reach a level of significance (P = 0.08). Multivariate analysis revealed tumor stage as the only powerful factor (P = 0.02) correlated with distant metastasis.

CONCLUSIONS

The incidence of PTC shows a marked increase in females with the highest female/male ratio occurring at puberty. Childhood thyroid carcinoma frequently is associated with lymph node involvement, distant metastases, and extrathyroidal tumor infiltration. In children FTC appears to be less aggressive than PTC. Advanced local-regional extension stage appears to be the most powerful factor influencing the risk for distant metastases in children.