Cylindrical ionization chamber response in static and dynamic 6 and 15 MV photon beams

Purpose.To investigate the response of the CC13 ionization chamber under non-reference photon beam conditions, focusing on penumbra and build-up regions of static fields and on dynamic intensity-modulated beams.Methods. Measurements were performed in 6 MV 100 × 100, 20 × 100, and 20 × 20 mm²static fields. Monte Carlo calculations were performed for the static fields and for 6 and 15 MV dynamic beam sequences using a Varian multi-leaf collimator. The chamber was modelled using EGSnrc egs_chamber software. Conversion factors were calculated by relating the absorbed dose to air in the chamber air cavity to the absorbed dose to water. Correction and point-dose correction factors were calculated to quantify the conversion factor variations.Results. The correction factors for positions on the beam central axis and at the penumbra centre were 0.98-1.02 for all static fields and depths investigated. The largest corrections were obtained for chamber positions beyond penumbra centre in the off-axis direction. Point-dose correction factors were 0.54-0.71 at 100 mm depth and their magnitude increased with decreasing field size and measurement depth. Factors of 0.99-1.03 were obtained inside and near the integrated penumbra of the dynamic field at 100 mm depth, and of 0.92-0.94 beyond the integrated penumbra centre. The variations in the ionization chamber response across the integrated dynamic penumbra qualitatively followed the behaviour across penumbra of static fields.Conclusions. Without corrections, the CC13 chamber was of limited usefulness for profile measurements in 20-mm-wide fields. However, measurements in dynamic small irregular beam openings resembling the conditions of pre-treatment patient quality assurance were feasible. Uncorrected ionization chamber response could be applied for dose verification at 100 mm depth inside and close to large gradients of dynamically accumulating high- and low-dose regions assuming 3% tolerance between measured and calculated doses.

Effects of COVID-19 on the Human Central Olfactory System: A Natural Pre-Post Experiment

BACKGROUND AND PURPOSE

Reduced olfactory function is the symptom with the highest prevalence in coronavirus disease 2019 (COVID-19) with nearly 70% of infected individuals experiencing partial or total loss of their sense of smell at some point during the disease. The exact cause is not known, but beyond peripheral damage, studies have demonstrated insults to both the olfactory bulb and central olfactory brain areas. However, these studies often lack both baseline pre-COVID-19 assessments and control groups, and the effects could, therefore, simply reflect pre-existing risk factors.

MATERIALS AND METHODS

Shortly before the COVID-19 outbreak, we completed an olfactory-focused study, which included structural MR brain images and a full clinical olfactory test. Opportunistically, we invited participants back 1 year later, including 9 participants who had experienced mild-to-moderate COVID-19 (C19+) and 12 who had not (C19-), creating a natural pre-post experiment with a control group.

RESULTS

Despite C19+ participants reporting subjective olfactory dysfunction, few showed signs of objectively altered function. Critically, all except 1 individual in the C19+ group had reduced olfactory bulb volume (average reduction, 14.3%), but this did not amount to a significant statistical difference compared with the control group (2.3%) using inference statistics. We found no morphologic differences in olfactory brain areas but stronger functional connectivity between olfactory brain areas in the C19+ group at the postmeasure.

CONCLUSIONS

Our data suggest that COVID-19 might cause long-term reduction in olfactory bulb volume and altered functional connectivity but with no discernible morphologic differences in cerebral olfactory regions.

Antimicrobial-resistant Salmonella is detected more frequently in feed milling equipment than in raw feed components or processed animal feed

Food for human and animal consumption can provide a vehicle for the transfer of pathogenic and antimicrobial‐resistant bacteria into the food chain. We investigated the antimicrobial susceptibility of 453 Salmonella isolates collected from raw feed components, equipment and finished feed from 17 commercial feed mills in Australia between 2012 and 2021. Previous studies have found Salmonella prevalence and the diversity of Salmonella serotypes are greatest in the raw feed components. We, therefore, hypothesised that we would find a greater proportion of antimicrobial‐resistant Salmonella isolates in the raw feed components compared to other sample types. We found that of 453 isolates tested, 356 (0.80) were susceptible to all antimicrobials tested, 49 (0.11) were nonsusceptible to streptomycin only and 48 (0.11) were resistant to two or more antimicrobials. Of the 48 antimicrobial‐resistant isolates, 44 were found in feed milling equipment, two in raw feed components and two in finished feed. Statistical analysis, using a logistic regression with random effects model, found that the population‐adjusted mean probability of detecting antimicrobial‐resistant Salmonella isolates from feed milling equipment of 0.39, was larger than the probability of detecting resistant isolates in raw feed components 0.01, (P < 0.001) and in finished feed, 0.11, (P = 0.006). This propensity for antimicrobial‐resistant bacteria to colonise feed milling equipment has not been previously reported. Further studies are required to understand the ecology of antimicrobial‐resistant Salmonella in the feed milling environment.

Effects of lung tissue characterization in radiotherapy of breast cancer under deep inspiration breath hold when using Monte Carlo dosimetry

PURPOSE

To investigate the sensitivity of Monte Carlo (MC) calculated lung dose distributions to lung tissue characterization in external beam radiotherapy of breast cancer under Deep Inspiration Breath Hold (DIBH).

METHODS

EGSnrc based MC software was employed. Mean lung densities for one hundred patients were analysed. CT number frequency and clinical dose distributions were calculated for 15 patients with mean lung density below 0.14 g/cm³. Lung volume with a pre-defined CT numbers was also considered. Lung tissue was characterized by applying different CT calibrations in the low-density region and air-lung tissue thresholds. Dose impact was estimated by Dose Volume Histogram (DVH) parameters.

RESULTS

Mean lung densities below 0.14 g/cm³ were found in 10% of the patients. CT numbers below -960 HU dominated the CT frequency distributions with a high rate of CT numbers at -990 HU. Mass density conversion approach influenced the DVH shape. V_4Gy and V_8Gy varied by 7% and 5% for the selected patients and by 9% and 3.5% for the pre-defined lung volume. V_16Gy and V_20Gy, were within 2.5%. Regions above 20 Gy were affected. Variations in air- lung tissue differentiation resulted in DVH parameters within 1%. Threshold at -990 HU was confirmed by the CT number frequency distributions.

CONCLUSIONS

Lung dose distributions were more sensitive to variations in the CT calibration curve below lung (inhale) density than to air-lung tissue differentiation. Low dose regions were mostly affected. The dosimetry effects were found to be potentially important to 10% of the patients treated under DIBH.

Targeted delivery of antisense oligonucleotides to pancreatic β-cells

Antisense oligonucleotide (ASO) silencing of the expression of disease-associated genes is an attractive novel therapeutic approach, but treatments are limited by the ability to deliver ASOs to cells and tissues. Following systemic administration, ASOs preferentially accumulate in liver and kidney. Among the cell types refractory to ASO uptake is the pancreatic insulin-secreting β-cell. Here, we show that conjugation of ASOs to a ligand of the glucagon-like peptide-1 receptor (GLP1R) can productively deliver ASO cargo to pancreatic β-cells both in vitro and in vivo. Ligand-conjugated ASOs silenced target genes in pancreatic islets at doses that did not affect target gene expression in liver or other tissues, indicating enhanced tissue and cell type specificity. This finding has potential to broaden the use of ASO technology, opening up novel therapeutic opportunities, and presents an innovative approach for targeted delivery of ASOs to additional cell types.

VIRUS — A Laboratory Information System for Clinical Virology

A system covering request registration, analytical orders, printing of worksheets, result reporting, result control and printing of patient reports is presented. Additionally, interim reports can be produced; accounting is automatic, and group requests and requests for new analyses of old samples can be handled. The system meets the demand for retrospective analysis which arises when acute intermediate and convalescent sera have to be analyzed simultaneously. Consequently, results from the same type of analysis performed on the same sample on different occasions can be handled and presented in a clear way on the VDU and on the report.

All work is performed on-line in real time via VDU screens. All data are stored on a 3 x 100 Mbyte disk chive which can accommodate approximately 6 years’ work.

The system has been implemented as a terminal system with 5 VDU: s and one line printer connected to an IBM 370/158 computer. The IMS data base management system has been utilized.

Lactate improves SAPS 3 prognostication

INTRODUCTION

Lactate concentration is known to be a strong predictor of mortality, but is not included in any of the major intensive care scorings systems such as the Simplified Acute Physiology Score (SAPS 3). The objective of this study was to investigate the prognostic value of lactate concentration when combined with SAPS 3.

MATERIALS AND METHODS

In the period of 2008 to June 2017 the general intensive care unit at Skåne University Hospital in Lund, Sweden had 5141 first-time admissions. Of these, 3039 patients had lactate concentrations analysed within 1 h of admission.

RESULTS

As expected, lactate concentration was found to be strongly related to 30-day mortality. Lactate concentration was found to be a SAPS 3 independent predictor of mortality (odds ratio 1.08, 95% confidence interval 1.05-1.11, P < 0.001), but did not improve the area under the receiver operating characteristic curve (AUC) (AUC 78.9% vs. 78.7%, P = 0.053). However, we found that lactate added prognostic value to SAPS 3 for patients with cardiac arrest (AUC 79.6% vs. 76.4%, P = 0.0082) and sepsis (AUC 75.1% vs. 72.7%, P = 0.033).

CONCLUSION

Even compared to our current prognostication model, SAPS 3, lactate concentration was found to be an independent predictor for all diagnoses, cardiac arrest and sepsis. The addition of lactate concentration level improved the AUC for cardiac arrest and sepsis, but not for all diagnoses.

Boys have better short-term and long-term survival rates after intensive care admissions than girls

AIM

We investigated possible gender differences in paediatric intensive care morbidity-adjusted mortality.

METHODS

In this study, data on all 21 972 paediatric intensive care admissions in Sweden between 2008 and 2015 were analysed regarding morbidity-adjusted survival, using Cox regression, with age, gender and estimated mortality ratio as dependent variables and using the standardised mortality ratio at 90 days after admission. The data were obtained from the Swedish Intensive Care Registry.

RESULTS

We found that boys had better overall survival than girls (hazard ratio 0.91 for boys, p = 0.035). In addition, the 90-day survival was also better for boys (standardised mortality ratio 0.85 for boys versus 1.02 for girls, p = 0.0014). The survival advantage was most evident in children less than a year old and for nonsurgical patients. The male advantage was also seen in children admitted with respiratory insufficiency and seizures and was furthermore independent of any concurrent cardiac condition. We did not find any gender difference in the intensity of care or length of stay when corrected for morbidity.

CONCLUSION

This study showed that boys have better outcomes than girls after intensive care admissions. The difference does not seem to be based on inequality of care.

Dental status in nursing home residents with domiciliary dental care in Sweden

OBJECTIVE

To describe the dental health status of elderly people in nursing homes receiving domiciliary dental care.

DESIGN

Case note review.

CLINICAL SETTING

Nursing homes in 8 Swedish counties.

PARTICIPANTS

Care dependent elderly people (≥65 years).

METHODS

Clinical data, including the number of remaining natural teeth, missing and decayed teeth (manifest dental caries) and root remnants, recorded by dentists according to standard practices. Medical and dental risk assessments were performed.

RESULTS

Data were available for 20,664 patients. Most were women (69.1%), with a mean age of 87.1 years (SD 7.42, range 65-109). The mean age for men was 83.5 years (SD 8.12, range 65-105). Two or more medical conditions were present in most of the population. A total of 16,210 individuals had existing teeth of whom 10,974 (67.7%) had manifest caries. The mean number of teeth with caries was 5.0 (SD 5.93) corresponding to 22.8% of existing teeth. One in four individuals were considered to have a very high risk in at least one professional dental risk assessment category.

CONCLUSIONS

Care dependent elderly in nursing homes have very poor oral health. There is a need to focus on the oral health-related quality of life for this group of frail elderly during their final period of life.

Randomized clinical trial of Appendicitis Inflammatory Response score-based management of patients with suspected appendicitis

BACKGROUND

The role of imaging in the diagnosis of appendicitis is controversial. This prospective interventional study and nested randomized trial analysed the impact of implementing a risk stratification algorithm based on the Appendicitis Inflammatory Response (AIR) score, and compared routine imaging with selective imaging after clinical reassessment.

METHOD

Patients presenting with suspicion of appendicitis between September 2009 and January 2012 from age 10 years were included at 21 emergency surgical centres and from age 5 years at three university paediatric centres. Registration of clinical characteristics, treatments and outcomes started during the baseline period. The AIR score-based algorithm was implemented during the intervention period. Intermediate-risk patients were randomized to routine imaging or selective imaging after clinical reassessment.

RESULTS

The baseline period included 1152 patients, and the intervention period 2639, of whom 1068 intermediate-risk patients were randomized. In low-risk patients, use of the AIR score-based algorithm resulted in less imaging (19·2 versus 34·5 per cent; P < 0·001), fewer admissions (29·5 versus 42·8 per cent; P < 0·001), and fewer negative explorations (1·6 versus 3·2 per cent; P = 0·030) and operations for non-perforated appendicitis (6·8 versus 9·7 per cent; P = 0·034). Intermediate-risk patients randomized to the imaging and observation groups had the same proportion of negative appendicectomies (6·4 versus 6·7 per cent respectively; P = 0·884), number of admissions, number of perforations and length of hospital stay, but routine imaging was associated with an increased proportion of patients treated for appendicitis (53·4 versus 46·3 per cent; P = 0·020).

CONCLUSION

AIR score-based risk classification can safely reduce the use of diagnostic imaging and hospital admissions in patients with suspicion of appendicitis. Registration number: NCT00971438 ( http://www.clinicaltrials.gov).

Factors Affecting Older Persons' Ability to Manage Oral Hygiene: A Qualitative Study

A great challenge for the dental service is to support the growing group of elderly people with preserving good oral health throughout their lives. Limitations in the ability to manage oral hygiene and an increased number of risk factors are often reflected by poor oral health. Thus, the need for individualized support and oral health procedures based on the older person's condition is significant. Deficiencies in the motor skills needed to manage oral hygiene are well known, but other factors that affect the ability are not well studied. The aim of the present study was to identify factors that may affect an elderly person's ability to perform oral hygiene self-care, which is the first step to develop a more comprehensive "oral hygiene ability index." The design of the study was qualitative. Data were collected from 4 focus group interviews with a total of 23 participants. Three of the groups consisted of dental hygienists, occupational therapists, and assistant nurses, all working with elderly persons. The fourth group was made up of elderly people (72-89 years). Content analysis was used to analyze the data. The latent content was formulated into the core category, "oral hygiene-a complex activity." Three categories emerged: "psychological," "environmental," and "functional" dimensions. The psychological dimension described attitude/motivation, emotions, and cognitive factors. The environmental dimension included practical conditions and social context. The functional dimension dealt with bodily and oral function as well as the senses. In conclusion, self-care with respect to oral hygiene is a complex activity for elderly persons and includes a large number of factors. These factors should be taken into consideration when developing a future oral hygiene ability index. Knowledge Transfer Statement: Various factors may affect the ability to manage oral hygiene self-care. Impaired ability to manage oral hygiene, in combination with an increased number of risk factors, often results in deteriorating oral health and impaired quality of life in older persons. Factors necessary to manage oral hygiene were identified in a qualitative study of dental hygienists, occupational therapists, and assistant nurses, all working with elderly patients, and a group of elderly persons. The results of this study may be important for clinical oral health work with older patients and for the planning of oral health and social care interventions for the growing group of older people.

Linac4 H⁻ ion sources

CERN's 160 MeV H(-) linear accelerator (Linac4) is a key constituent of the injector chain upgrade of the Large Hadron Collider that is being installed and commissioned. A cesiated surface ion source prototype is being tested and has delivered a beam intensity of 45 mA within an emittance of 0.3 π ⋅ mm ⋅ mrad. The optimum ratio of the co-extracted electron- to ion-current is below 1 and the best production efficiency, defined as the ratio of the beam current to the 2 MHz RF-power transmitted to the plasma, reached 1.1 mA/kW. The H(-) source prototype and the first tests of the new ion source optics, electron-dump, and front end developed to minimize the beam emittance are presented. A temperature regulated magnetron H(-) source developed by the Brookhaven National Laboratory was built at CERN. The first tests of the magnetron operated at 0.8 Hz repetition rate are described.

Discovery of AZD8165 – a clinical candidate from a novel series of neutral thrombin inhibitors

A novel series of neutral thrombin inhibitors has been developed using a selection process based on docking experiments and property calculations and predictions.

The impact of oral health on daily performances and its association with clinical variables in a population in Zambia

OBJECTIVE

The aim of this study was to investigate oral impacts on daily performance and to relate these data to oral clinical variables.

MATERIAL AND METHODS

The study was performed at a dental clinic in Livingstone, Zambia, and included 78 subjects (mean age 28, range 15-48 years) consecutively recruited in connection with a dental care visit. Data were collected through a structured interview using the Oral Impacts on Daily Performances (OIDP) index measuring oral health-related quality of life followed by a clinical examination.

RESULTS

Oral health affected one or more daily performances during the last 6 months for 61.5% of the subjects. 'Difficulty of eating and enjoying food' was the performance reported most frequently (42.3%), and 'speaking and pronouncing clearly' was least often reported (10.3%). DMFT was 3.8, ±3.6 (mean ± SD; range 0-15). A majority of the individuals had periodontal pockets ≥4 mm (mean 4.3, ±2.6) (94.9%) and gingival bleeding on probing >20% (88.5%). Two or more decayed teeth were shown to be significantly associated (OR 4.6, CI 1.2-17.1) with one or more oral impacts on daily performances in a multivariate logistic regression analysis.

CONCLUSIONS

This study shown that there is a significant association between decayed teeth and oral impacts on daily performances. More research is needed, however, for deeper understanding of oral health problems and their impacts on daily life in Zambia.

Predicting exposure of wildlife in radionuclide contaminated wetland ecosystems

Many wetlands support high biodiversity and are protected sites, but some are contaminated with radionuclides from routine or accidental releases from nuclear facilities. This radiation exposure needs to be assessed to demonstrate radiological protection of the environment. Existing biota dose models cover generic terrestrial, freshwater, and marine ecosystems, not wetlands specifically. This paper, which was produced under IAEA's Environmental Modelling for Radiation Safety (EMRAS) II programme, describes an evaluation of how models can be applied to radionuclide contaminated wetlands. Participants used combinations of aquatic and terrestrial model parameters to assess exposure. Results show the importance of occupancy factor and food source (aquatic or terrestrial) included. The influence of soil saturation conditions on external dose rates is also apparent. In general, terrestrial parameters provided acceptable predictions for wetland organisms. However, occasionally predictions varied by three orders of magnitude between assessors. Possible further developments for biota dose models and research needs are identified.

Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful indication on the flow mode, and a visualization of the radial material distribution can be obtained. A benefit of this system is its potential to be mounted at any axial height of a two-phase test section without requirements for pre-fabricated entrances or windows. This could mean a significant increase in flexibility of the void distribution assessment capability at many existing two-phase test loops.

Status and operation of the Linac4 ion source prototypes

CERN's Linac4 45 kV H(-) ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma, and pulsed high voltages are described. The first experimental results of two prototypes relying on 2 MHz RF-plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H(-) beam of 16-22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator, and chopper of Linac4.

Establishing a database of radionuclide transfer parameters for freshwater wildlife

Environmental assessments to evaluate potentials risks to humans and wildlife often involve modelling to predict contaminant exposure through key pathways. Such models require input of parameter values, including concentration ratios, to estimate contaminant concentrations in biota based on measurements or estimates of concentrations in environmental media, such as water. Due to the diversity of species and the range in physicochemical conditions in natural ecosystems, concentration ratios can vary by orders of magnitude, even within similar species. Therefore, to improve model input parameter values for application in aquatic systems, freshwater concentration ratios were collated or calculated from national grey literature, Russian language publications, and refereed papers. Collated data were then input into an international database that is being established by the International Atomic Energy Agency. The freshwater database enables entry of information for all radionuclides listed in ICRP (1983), in addition to the corresponding stable elements, and comprises a total of more than 16,500 concentration ratio (CRwo-water) values. Although data were available for all broad wildlife groups (with the exception of birds), data were sparse for many organism types. For example, zooplankton, crustaceans, insects and insect larvae, amphibians, and mammals, for which there were CRwo-water values for less than eight elements. Coverage was most comprehensive for fish, vascular plants, and molluscs. To our knowledge, the freshwater database that has now been established represents the most comprehensive set of CRwo-water values for freshwater species currently available for use in radiological environmental assessments.

A new approach to predicting environmental transfer of radionuclides to wildlife: a demonstration for freshwater fish and caesium

The application of the concentration ratio (CR) to predict radionuclide activity concentrations in wildlife from those in soil or water has become the widely accepted approach for environmental assessments. Recently both the ICRP and IAEA have produced compilations of CR values for application in environmental assessment. However, the CR approach has many limitations, most notably, that the transfer of most radionuclides is largely determined by site-specific factors (e.g. water or soil chemistry). Furthermore, there are few, if any, CR values for many radionuclide-organism combinations. In this paper, we propose an alternative approach and, as an example, demonstrate and test this for caesium and freshwater fish. Using a Residual Maximum Likelihood (REML) mixed-model regression we analysed a dataset comprising 597 entries for 53 freshwater fish species from 67 sites. The REML analysis generated a mean value for each species on a common scale after REML adjustment taking account of the effect of the inter-site variation. Using an independent dataset, we subsequently test the hypothesis that the REML model outputs can be used to predict radionuclide, in this case radiocaesium, activity concentrations in unknown species from the results of a species which has been sampled at a specific site. The outputs of the REML analysis accurately predicted (137)Cs activity concentrations in different species of fish from 27 Finnish lakes; these data had not been used in our initial analyses. We recommend that this alternative approach be further investigated for other radionuclides and ecosystems.

The IAEA handbook on radionuclide transfer to wildlife

An IAEA handbook presenting transfer parameter values for wildlife has recently been produced. Concentration ratios (CRwo-media) between the whole organism (fresh weight) and either soil (dry weight) or water were collated for a range of wildlife groups (classified taxonomically and by feeding strategy) in terrestrial, freshwater, marine and brackish generic ecosystems. The data have been compiled in an on line database, which will continue to be updated in the future providing the basis for subsequent revision of the Wildlife TRS values. An overview of the compilation and analysis, and discussion of the extent and limitations of the data is presented. Example comparisons of the CRwo-media values are given for polonium across all wildlife groups and ecosystems and for molluscs for all radionuclides. The CRwo-media values have also been compared with those currently used in the ERICA Tool which represented the most complete published database for wildlife transfer values prior to this work. The use of CRwo-media values is a pragmatic approach to predicting radionuclide activity concentrations in wildlife and is similar to that used for screening assessments for the human food chain. The CRwo-media values are most suitable for a screening application where there are several conservative assumptions built into the models which will, to varying extents, compensate for the variable data quality and quantity, and associated uncertainty.

Sequences of multiple bacterial genomes and a Chlamydia trachomatis genotype from direct sequencing of DNA derived from a vaginal swab diagnostic specimen

Ultra-deep Illumina sequencing was performed on whole genome amplified DNA derived from a Chlamydia trachomatis-positive vaginal swab. Alignment of reads with reference genomes allowed robust SNP identification from the C. trachomatis chromosome and plasmid. This revealed that the C. trachomatis in the specimen was very closely related to the sequenced urogenital, serovar F, clade T1 isolate F-SW4. In addition, high genome-wide coverage was obtained for Prevotella melaninogenica, Gardnerella vaginalis, Clostridiales genomosp. BVAB3 and Mycoplasma hominis. This illustrates the potential of metagenome data to provide high resolution bacterial typing data from multiple taxa in a diagnostic specimen.

Correction for dynamic bias error in transmission measurements of void fraction

Dynamic bias errors occur in transmission measurements, such as X-ray, gamma, or neutron radiography or tomography. This is observed when the properties of the object are not stationary in time and its average properties are assessed. The nonlinear measurement response to changes in transmission within the time scale of the measurement implies a bias, which can be difficult to correct for. A typical example is the tomographic or radiographic mapping of void content in dynamic two-phase flow systems. In this work, the dynamic bias error is described and a method to make a first-order correction is derived. A prerequisite for this method is variance estimates of the system dynamics, which can be obtained using high-speed, time-resolved data acquisition. However, in the absence of such acquisition, a priori knowledge might be used to substitute the time resolved data. Using synthetic data, a void fraction measurement case study has been simulated to demonstrate the performance of the suggested method. The transmission length of the radiation in the object under study and the type of fluctuation of the void fraction have been varied. Significant decreases in the dynamic bias error were achieved to the expense of marginal decreases in precision.

The prevalence of atrial fibrillation in a geographically well-defined population in northern Sweden: implications for anticoagulation prophylaxis

OBJECTIVES

The aims of this study were to evaluate the community-based prevalence of atrial fibrillation (AF) in a western society using a geographically well-defined population in the northern part of Sweden as a reference and to estimate the proportion of patients eligible for oral anticoagulation (OAC) prophylactic therapy according to the stroke risk indices CHADS2 and CHA2 DS2 -VASc. Bleeding risk was assessed using the HAS-BLED score.

DESIGN

The study population was recruited from AURICULA, a Swedish national quality register for patients receiving anticoagulation treatment. All patients with the diagnosis AF in the catchment area are registered in AURICULA.

RESULTS

Of the 65 532 inhabitants in the catchment area, 1616 were diagnosed with AF (1200 cases were characterized as chronic AF). Thus, the overall prevalence of AF was 2.5%. The prevalence increased with age from 6.3% in patients over 55 years of age to 13.8% in those over 80 years. The prevalence was higher in men than in women in all age groups. Overall, 56.3% and 85.1% of the population were at high risk of stroke (≥2 points) according to CHADS2 and CHA2 DS2 -VASc, respectively. In addition, 26.9% had an increased bleeding risk according to HAS-BLED.

CONCLUSION

Within this large Caucasian population, we identified the highest community-based prevalence of AF to date. The prevalence was strongly associated with increasing age and male gender. Using CHA2 DS2 -VASc instead of CHADS(2) widened the indication for OAC prophylactic therapy of AF in this population.

Long-term quality of life in patients with permanent sigmoid colostomy

AIM

The study aimed to assess quality of life (QoL) in patients with a sigmoid colostomy using a simple general and disease-specific instrument. A subgroup not doing well was identified and examined further.

METHOD

The Short Health Scale (SHS) is a four-item instrument exploring severity of symptoms, function in daily life, worry, and general well-being, using visual analogue scales ranging from 0 to 100 where 100 is the worst possible situation. The SHS was delivered to 206 patients with a sigmoid colostomy. It was returned by 181 (87.9%) patients [88 men; median age 73 (33-91) years]. Follow-up was 61 (10-484) months for 178 (86.4%) patients returning usable questionnaires. A subgroup of 16 patients scoring more than 50 in all four items of the SHS was further examined with StomaQOL where 100 is best possible.

RESULTS

The median score for severity of symptoms was 18 (2-95), function in daily life 21 (0-95), worry 17 (3-98) and general well-being 22 (0-99). A score of < 50 in the SHS was recorded in 84.9%, 82.1%, 79.9% and 70.5% respectively. In the group scoring more than 50 in all four items patients diagnosed with irritable bowel syndrome constituted 43.8% to compare with 5.6% in the entire study group (P < 0.001). Median score for StomaQOL was 37 (22-62) in this group.

CONCLUSION

Most patients with a permanent sigmoid colostomy have a good QoL consistent with previous findings. However, this is reduced in a subgroup of patients diagnosed with irritable bowel syndrome.

Split stoma in resectional surgery of high-risk patients with ileocolonic Crohn's disease

AIM

The aim of this retrospective study of ileocolonic resection in patients with Crohn's disease was to compare the outcome of primary anastomosis with that of split stoma and delayed anastomosis in a high-risk setting.

METHOD

From 1995 to 2006, 132 patients had 146 operations for ileocolonic Crohn's disease. Preoperative data, including risk factors for complications, were obtained from a prospectively registered database. Operations on patients who had two or more preoperative risk factors (n = 76) were considered to be high-risk operations and formed the main study. Primary outcome variables were postoperative anastomotic complications and the alteration in the number of preoperative risk factors achieved by a delayed anastomosis. Secondary outcome was time in hospital and the number of operations performed.

RESULTS

Early anastomotic complications were diagnosed in 19% (11/57) of patients receiving a primary anastomosis compared with 0% (0/19) of patients after a delayed anastomosis (P = 0.038). The mean number of risk factors in the split stoma group was 3.5 at the time of resection and 0.2 when the split stoma was reversed (P < 0.0001). The total number of operations was 1.9 ± 1.5 (mean ± SD) after a primary anastomosis and 2.0 ± 0.2 after a split stoma (P = 0.70). Total in-hospital time for all operations was 20.9 ± 35.6 days after a primary anastomosis and 17.8 ± 10.4 days after a delayed anastomosis (P = 0.74).

CONCLUSION

Delayed anastomosis after ileocolonic resection in high-risk Crohn's disease patients was associated with a reduction in the number of preoperative risk factors and fewer anastomotic complications. Hospital stay and number of operations were similar after delayed and primary anastomosis in high-risk patients.

Beam purification by photodetachment (invited)

Ion beam purity is of crucial importance to many basic and applied studies in nuclear science. Selective photodetachment has been proposed to suppress unwanted species in negative ion beams while preserving the intensity of the species of interest. A highly efficient technique based on photodetachment in a gas-filled radio frequency quadrupole ion cooler has been demonstrated. In off-line experiments with stable ions, up to 10(4) times suppression of the isobar contaminants in a number of interesting radioactive negative ion beams has been demonstrated. For selected species, this technique promises new experimental possibilities in studies on exotic nuclei, accelerator mass spectrometry, and fundamental properties of negative atomic and molecular ions.

WIN55,212-2 induces cytoplasmic vacuolation in apoptosis-resistant MCL cells

Cannabinoid receptors 1 (CB1) and/or 2 (CB2) are overexpressed in many types of human malignancies including mantle cell lymphoma (MCL). Agonists to CB1 and CB2 promote ceramide de novo synthesis, p38–mitogen-activated protein kinase-dependent activation of caspase-3 and apoptotic cell death in most MCLs. However, in this report we describe that in some MCLs the response to treatment with cannabinoids decreased cell viability as assessed by metabolic activity but did not involve the caspase-3 cascade or loss of plasma membrane integrity. Both primary cells from one MCL patient and the MCL cell line Granta519 responded to treatment with cannabinoids by formation of cycloheximide-sensitive cytoplasmic vacuoles, but did not enter apoptosis. The persistent expression of mammalian homolog of Atg8 with microtubule-associated protein-1 light chain-3 II (LC3 II) and p62, as well as the lack of protection from chloroquine, indicates that lysosomal degradation is not involved in this cytoplasmic vacuolation process, distinguishing from classical autophagy. Transmission electron microscopy images and immunofluorescence staining of endoplasmic reticulum (ER) chaperone calreticulin showed that the vacuoles were of ER origin and that chromatin remained normal. These features resemble paraptosis-like cell death—a third type of a programmed cell death not previously described in response to cannabinoids.

The invisible work with tobacco cessation - strategies among dental hygienists

OBJECTIVE

This study elucidates dental hygienists' experiences of work with tobacco cessation among patients who smoke or use snuff.

METHODS

Data were obtained and categorized by interviewing 12 dental hygienists, who worked actively with tobacco cessation interventions. Qualitative content analysis was used for analysis.

RESULTS

The latent content was formulated into the core category 'the invisible oral health promotion work'. The informants thought that they had a responsibility to work with tobacco cessation. They perceived the financial system in which they perform the activity as frustrating, because tobacco cessation has no treatment code in the dental care insurance. This was one of several reasons why they had to integrate it in other treatment procedures. The results identified three categories: 'balance in the meeting', 'possibilities and hindrance' and 'procedures'. In the narratives, both positive and negative aspects were displayed.

CONCLUSIONS

The financial conditions for tobacco cessation interventions need to be reformed and the activity has to be given a higher priority in the organization of dental care. Practical training in performing tobacco cessation interventions is important during the dental hygiene education; otherwise, tobacco cessation interventions will remain invisible in oral health promotion in the future.

Evaluation of the Dental Hygienist Beliefs Survey; test-retest assessment in a group of general dental patients

OBJECTIVE

To evaluate the Dental Hygienist Beliefs Survey (DHBS) and the test-retest reliability of DHBS in a group of general dental patients.

MATERIAL AND METHODS

The DHBS, which is a questionnaire constructed to assess patients' specific attitudes towards dental hygienists (DHs), was distributed together with the Dental Anxiety Scale adapted to specifically assess fear of DH treatment (DHAS). It was hypothesized that DHBS would correlate with DHAS and gender. The questionnaires were consecutively distributed to 80 patients at their first visit and after a clinical examination performed by a DH student. Retest assessments of DHBS were conducted approximately two weeks later in conjunction with the next visit at the DH student and before treatment (scaling session). The final study sample included 77 adult general dental patients in treatment at an education clinic for DH students.

RESULTS

The results verified a statistically significant correlation between DHBS and DHAS. The DHBS sum of scores showed high internal consistency with Cronbach's a coefficient of 0.88 and 0.91 at the first and second assessments, respectively, and the test-retest reliability of the DHBS was acceptable with intraclass correlation coefficient of 0.76. No statistically significant association was found between DHBS and gender.

CONCLUSION

The results suggest that the DHBS is a reliable and stable scale to use to assess patients' specific attitudes towards DHs. Moreover, DH beliefs are associated with fear of DH treatment.

Ion optical design of a collinear laser-negative ion beam apparatus

An apparatus for photodetachment studies on atomic and molecular negative ions of medium up to heavy mass (M ≃ 500) has been designed and constructed. Laser and ion beams are merged in the apparatus in a collinear geometry and atoms, neutral molecules and negative ions are detected in the forward direction. The ion optical design and the components used to optimize the mass resolution and the transmission through the extended field-free interaction region are described. A 90° sector field magnet with 50 cm bending radius in combination with two slits is used for mass dispersion providing a resolution of M∕ΔM≅800 for molecular ions and M∕ΔM≅400 for atomic ions. The difference in mass resolution for atomic and molecular ions is attributed to different energy distributions of the sputtered ions. With 1 mm slits, transmission from the source through the interaction region to the final ion detector was determined to be about 0.14%.

Protection of the environment from ionising radiation in a regulatory context--an overview of the PROTECT coordinated action project

The outcome of the PROTECT project (Protection of the Environment from Ionising Radiation in a Regulatory Context) is summarised, focusing on the protection goal and derivation of dose rates which may detrimentally affect wildlife populations. To carry out an impact assessment for radioactive substances, the estimated dose rates produced by assessment tools need to be compared with some form of criteria to judge the level of risk. To do this, appropriate protection goals need to be defined and associated predefined dose rate values, or benchmarks, derived and agreed upon. Previous approaches used to estimate dose rates at which there may be observable changes in populations or individuals are described and discussed, as are more recent derivations of screening benchmarks for use in regulatory frameworks. We have adopted guidance and procedures used for assessment and regulation of other chemical stressors to derive benchmarks. On the basis of consultation with many relevant experts, PROTECT has derived a benchmark screening dose rate, using data on largely reproductive effects to derive species sensitivity distributions, of 10 microGy h(-1) which can be used to identify situations which are below regulatory concern with a high degree of confidence.