Unique territorial and sub-chromosomal organization revealed in the holocentric moth Bombyx mori

The hallmarks of chromosome organization in multicellular eukaryotes are chromosome territories (CT), chromatin compartments, and different types of domains, including topologically associated domains (TADs). Yet, most of these concepts derive from analyses of organisms with monocentric chromosomes. Here we describe the 3D genome architecture of an organism with holocentric chromosomes, the silkworm Bombyx mori . At the genome-wide scale, B. mori chromosomes form highly separated territories and lack substantial trans contacts. As described in other eukaryotes, B. mori chromosomes segregate into an active A and an inactive B compartment. Remarkably, we also identify a third compartment, Secluded "S", with a unique contact pattern. Compartment S shows strong enrichment of short-range contacts and depletion of long-range contacts. It hosts a unique combination of genetic and epigenetic features, localizes at the periphery of CTs and shows developmental plasticity. Biophysical modeling shows that formation of such secluded domains requires a new mechanism - a high density of extruded loops within them along with low level of extrusion and compartmentalization of A and B. Together with other evidence of loop extrusion in interphase, this suggests SMC-mediated loop extrusion in this insect. Overall, our analyses highlight the evolutionary plasticity of 3D genome organization driven by a new combination of known processes.

Patent foramen ovale closure: a comparison between two types of devices in a retrospective cohort

Background

Patent foramen ovale (PFO) closure has been shown to reduce the risk of recurrent stroke in selected patients. Different PFO occluding devices have been validated by the authorities and are used in the clinical practice.

Purpose

The main purpose of this study is to compare the use of two types of devices for PFO closure, the GORE CARDIOFORM Septal occluder and the AMPLATZER occluders (PFO or CRIBIFORM) in terms of major clinical safety and efficacy outcomes.

Methods

In this single-center retrospective study, the final cohort comprised 182 patients who underwent PFO closure between January 2012 and May 2019 (mean age 57±13 years, 34% males). The population was divided in two groups according to the device used (GORE CARDIOFORM Septal occluder [n=66, 36%] or the AMPLATZER occluders [n=116, 64%]). The endpoints assessed at 6 months, were the presence of a significant shunt (at least moderate [10–25 microbubbles] at rest or during the Valsalva manoeuvre), the incidence of supraventricular arrythmias, recurrent stroke, or serious device-related adverse events.

Results

At 6 months, a small percentage of patients with significant residual shunt was found in both the GORE and the AMPLATZER groups (7% vs 14% respectively, p=0.182). The incidence of supraventricular arrythmias was lower in the GORE as compared to the AMPLATZER group (9.1% vs 22.4% respectively, p=0.023). During the 6-month follow-up period there were 3 ischemic strokes, all of them in the AMPLATZER group, but this difference did not reach statistical significance (p=0.188). Finally, no serious device-related adverse events were noted in the total cohort.

Conclusion

PFO closure with a GORE device is related to lower incidence of supraventricular arrythmias at 6 months. The presence of a significant residual shunt and the incidence of recurrent stroke were comparable between both groups.

Funding Acknowledgement

Type of funding sources: None.

A multi institutional comparison of imaging dose and technique protocols for neonatal chest radiography

INTRODUCTION

The focus on paediatric radiation dose reduction supports reevaluation of paediatric imaging protocols. This is particularly important in the neonates where chest radiographs are frequently requested to assess respiratory illness and line placement. This study aims to assess the impact of neonatal chest radiographic protocols on patient dose in four hospitals in different countries.

METHODS

Exposure parameters, collimation, focus to skin distance (FSD) and radiation dose from 200 neonatal chest radiographs were registered prospectively. Inclusion criteria consisted of both premature and full-term neonates weighing between 1000 and 5000 g. Only data from the examinations meeting diagnostic criteria and approved for the clinical use were included. Radiation dose was assessed using dose area product (DAP).

RESULTS

The lowest DAP value (4.58 mGy cm²) was recorded in the Norwegian hospital, employing a high kVp, low mAs protocol using a DR system. The Canadian hospital recorded the highest DAP (9.48), using lower kVp and higher mAs with a CR system, including the addition of a lateral projection. The difference in the mean DAP, weight, field of view (FOV) and kVp between the hospitals is statistically significant (p < 0.001).

CONCLUSION

Use of non-standardised imaging protocols in neonatal chest radiography results in differences in patient dose across hospitals included in the study. Using higher kVp, lower mAs and reducing the number of lateral projections to clinically relevant indications result in a lower DAP measured in the infant sample studied. Further studies to examine image quality based on exposure factors and added filtration are recommended.

IMPLICATIONS FOR PRACTICE

Reevaluation of paediatric imaging protocols presents an opportunity to reduce patient dose in a population with increased sensitivity to ionising radiation.

P703 A breathtaking heart. The loeffler"s endocarditis

This is a 72 year-old man known for idiopathic HES with endomyocardial fibrosis and moderate aortic regurgitation, treated with corticosteroids and antithrombotics. Two months prior to admission, he develops progressive exertional dyspnea reaching NYHA 3 class, with concomitant peripheral edema and rise in NT-proBNP. Cardiac transthoracic work-up shows a preserved left ventricular ejection fraction, but more marked dilatation with decrease in left ventricular volume due to a large echodense mass in the apex. The transmitral flow is restrictive, and the aortic regurgitation moderate. In view of this rapid evolution, resection of the left ventricular mass with concomitant aortic valve replacement is performed. Pathology confirmed eosinophilic infiltration.

First described in 1975, hypereosinophilic syndrome (HES) is a rare pathology that is defined as an absolute eosinophil count (&gt;1,5 G/L) in the peripheral blood with eosinophil-mediated organ damage and /or dysfunction. We know three mains categories; primary (or neoplastic), secondary (or reactive) and idiopathic. Cardiac involvement is uncertain and cardiac injury does not clearly correlate with degree of peripheral eosinophilia. Heart tissue damage evolves through three stages (necrotic, intermediate and fibrotic). Endomyocardial fibrosis and eosinophilic myocarditis, also known as "Loeffler’s endocarditis", are major causes of morbidity and mortality among patients with HES. Echocardiography plays a crucial role in initial diagnosis of endomyocardial fibrosis, displaying myocardial wall thickening, signs of restriction (mitral inflow with large E wave and small A wave; E/A ratio greater than 2, short deceleration time less than 150 ms) and intracardiac thrombus (fixed mass embedding left ventricular apex). Valve regurgitation is another possible complication due to entrapment of the chordae tendinae and/or leaflets during the fibrotic stage of this disease. Cardiac MRI is another important diagnostic tool for precising cardiac involvement. Despite of steadily improving noninvasive diagnostic imaging methods, endomyocardial biosy still remains the gold standard exam and ultrasounds work-up is crucial for follow-up.

In conclusion, endomyocardial fibrosis is a rare cause of restrictive cardiomyopathy characterized by echocardiographic sign of elevated filling pressure, progressive endomyocardial thickening, valve regurgitation and possible intracardiac thrombus formation. This case underlines the importance of echocardiography in initial diagnosis and regular follow-up of this type of patients, in order to adapt medical treatment and monitor hemodynamic evolution of the restrictive physiology and of valvular damage.

Abstract P703 Figure. HES-3

P755The impact of levothyroxine on cardiac function in older adults with subclinical hypothyroidism: a randomized clinical trial

Importance

Subclinical hypothyroidism has been associated with heart failure, but no conclusive clinical trial assessed whether treating subclinical hypothyroidism with levothyroxine has an impact on cardiac function.

Objective

To assess the impact of levothyroxine treatment on cardiac function in subclinical hypothyroidism.

Design

This is a randomized, double-blind placebo-controlled, multicenter Swiss substudy within the TRUST trial.

Participants

Participants aged ≥65 years with subclinical hypothyroidism.

Intervention

Levothyroxine to achieve TSH normalization, or placebo including mock titrations.

Main outcome measures

Primary outcomes, assessed by echocardiography at the end of the trial were the left ventricular ejection fraction (LVEF, normal defined as >50%) for systolic function and the ratio between mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (e' (E/e' ratio) for diastolic function. Secondary outcomes included transmitral E and A waves, e' lateral/septal, left atrial (LA) volume index and systolic pulmonary artery pressure.

Results

Of 217 randomized Swiss participants of the TRUST trial, 185 (mean age 74.1 years, 47% women, mean TSH at baseline 6.35 ± SD 1.95 mIU/L) underwent echocardiography. After a median treatment duration of 18.4 months, the mean TSH among participants randomized to levothyroxine (n=95) decreased to 3.55 mIU/L, whereas it remained elevated in the placebo group (n=89; 5.29 mIU/L). The mean LVEF was similar in both arms (adjusted between-group difference 0.4%, 95% CI −1.8% to 2.5%, P=0.72) and no significant differences were found for the E/e' ratio (adjusted between-group difference 0.4, 95% CI −0.7 to 1.4, P=0.47). In intention-to-treat and per-protocol analyses, no clinically significant differences were found for secondary diastolic function parameters: e' lateral 8 vs. 8 cm/s, P=0.54; e' septal 6 vs. 6 cm/s, P=0.75; LA volume index 34 vs. 33 ml/m2, P=0.57; E/A ratio 0.8 vs. 0.8, P=0.94; E deceleration time 225 vs. 216 ms, P=0.27, except for systolic pulmonary artery pressure (37 mm Hg in the levothyoxine group vs. 33 mm Hg in the placebo group, P=0.02 intention-to-treat and P=0.06 per protocol)

Conclusion

Treatment of subclinical hypothyroidism with levothyroxine was not associated with benefits regarding systolic and diastolic heart function in older adults with subclinical hypothyroidism.

Infected and apoptotic cells in the IBDV-infected bursa of Fabricius, studied by double-labelling techniques

Infections of young chickens with infectious bursal disease virus (IBDV) result in depletion of lymphoid cells of the bursa of Fabricius (BF) due to necrosis and apoptotic processes. Interactions between IBDV and lymphoid cells were investigated by labelling paraffin-embedded tissue sections of infected BF with combinations of either immunohistochemistry (IHC), in situ hybridization (ISH) or in situ TUNEL reaction (IST). With regard to specificity and sensitivity, results of ISH were comparable to those of IHC. By double-labelling it was shown, for the first time, that viral antigen was present in most of the apoptotic cells. This suggests that IBDV may be directly involved in the induction of the apoptotic process. However, some cells also showed either viral antigen or DNA fragmentation, especially at the early stages of infection. It should be taken into account, therefore, that the apoptotic processes might also be induced by IBDV through indirect interaction between cells. Remarkably, in some of the infected lymphoid cells ISH signals were observed in the nucleolus.

Abstract TP382: Improving Door To Needle Time Using A Lean Transformation Rapid Improvement Process

Problem statement and background: Early initiation of thrombolysis is the key factor to improving quality of life in ischemic stroke patients. The facility has an internal goal of 100 percent. DTN < 60 minutes was not being met. The purpose of this project was to streamline the DTN time using the Lean Rapid Improvement Process (RI).

Methods: In January 2013, a Lean Transformation RI team was created and involved a collaboration of key frontline stakeholders. The team observed the current procedure, created an event map that detailed each step, and non-value added steps. The current process was analyzed to identify barriers to flow, and excessive lead times. The inter-disciplinary team clearly defined all stakeholder roles and streamlined process was created.

Results: The average DTN time in 2012 was 76 minutes with 40 percent less than 60 minutes (n=71). After the RI event, average minutes decreased from 68 minutes (n=39) in 2013 to 48 minutes (n=60) in 2014 and 39 minutes (n=49) through June 2015. Overall, the percentage increased from 54 percent in 2013, to 84 percent in 2014 and 94 percent in 2015. The greatest change in performance improvement was seen after the initiation of the RI process in 2015. This resulted in an average improvement of 36 minutes and 54% from 2012 to 2015. The fastest DTN time was 19 minutes.

Conclusion: The inter-disciplinary team collaborated to streamline the DTN process resulting in a significant reduction in time to tPA administration. The new process rapidly expedited the stroke alert procedure by facilitating timely movement, assessment and treatment of stroke victims. The streamlined procedure will be continued with the goal of ensuring that our performance continues to exceed the Target Stroke Phase II initiative of DTN < 45 minutes. The outcome of this improvement is optimizing the quality of life, patient satisfaction and enhanced team engagement.

[Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears]

Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

Strokes in the anterior circulation: comparison between bridging and intravenous thrombolysis

BACKGROUND AND PURPOSE

To compare safety and efficacy of bridging approach with intravenous (IV) thrombolysis in patients with acute anterior strokes and proximal occlusions.

PATIENTS AND METHODS

Consecutive patients with ischemic anterior strokes admitted within a 4 h 30 min window in two different centers were included. The first center performed IV therapy (alteplase 0.6 mg/kg) during 30 min and, in absence of clinical improvement, mechanical thrombectomy with flow restoration using a Solitaire stent (StS); the second carried out IV thrombolysis (alteplase 0.9 mg/kg) alone. Only T, M1 or M2 occlusions present on CT angiography were considered. Endpoints were clinical outcome and mortality at 3 months.

RESULTS

There were 63 patients in the bridging and 163 in the IV group. No significant differences regarding baseline characteristics were observed. At 3 months, 46% (n = 29) of the patients treated in the combined and 23% (n = 38) of those treated in the IV group had a modified Rankin scale (mRS) of 0-1 (P < 0.001). A statistical significant difference was observed for all sites of occlusion. In a logistic regression model, National Institute of Health Stroke Scale (NIHSS) and bridging therapy were independent predictors of good outcome (respectively, P = 0.001 and P = 0.0018). Symptomatic hemorrhage was documented in 6.3% vs 3.7% in the bridging and in the IV group, respectively (P = 0.32). There was no difference in mortality.

CONCLUSIONS

Our results suggest that patients treated with a bridging approach were more likely to have minimal or no deficit at all at 3 months as compared to the IV treated group.

Abstract NS10: Reducing Readmission Rates Bedside Nursing Led Discharge Rounds

BACKGROUND: A national benchmark does not exist identifying a rate for readmission of patients with ICD-9 codes for Stroke. The facility set its own benchmark goal of 13%. Analysis of the data for fiscal year 2013 found that 5 of 12 months of the fiscal year exceeded the benchmark goal ranging from 14.9% to 18.6%. Going into fiscal year 2014 It was realized that CMS would not reimbursement for readmissions within the first 30 days after discharge it was apparent that a process to reduce the readmission rate for stroke patients would be essential.

PURPOSE: Implementation of a discharge rounding will reduce readmission rates to the benchmark goal of 13% for patients admitted with a stroke.

METHOD: A discharge review process was started in September 2013 prior to the start of fiscal year 2014. The discharge review process was conducted by a phone conference including all patient care units. The participants from each unit included the director and charge nurse reviewing the readiness for discharge of patients on the unit. The information included in the process was a list of patients anticipated to be discharged and any potential barriers. This process would be evaluated at the end of each fiscal quarter with revisions made if goal was not met.

CONCLUSION/RESULTS The initial discharge process conference calling resulted in a reduction of readmission rate to an average of 8.9% for the stroke patient. It was noted that the process was generic and needed to be tailored for specific patient populations if it was to be sustainable. The process was revised and decentralized to the unit level with the addition of case manager. In April 2014 the data was reviewed and found a readmission percentage rate of 7.4% for the quarter. The success of the project was reducing the rate well below the benchmark that had been set. To continue the trend rounds were brought to the nursing care area to include the bedside nurse. A discharge rounding tool was to be complete prior to discharge rounds.

Data for the month of May 2014 shows a reduction in the rate to 5.3%. The discharge rounding has reduced the readmission rate for the Stroke patient and has exceeded the benchmark goal for two fiscal quarters suggesting the process is sustainable.

Efficacy of REACH Forgiveness across cultures

OBJECTIVE

This study investigates the efficacy of the 6-hour REACH Forgiveness intervention among culturally diverse undergraduates.

METHOD

Female undergraduates (N = 102) and foreign extraction (46.2%) and domestic (43.8%) students in the United States were randomly assigned to immediate treatment or waitlist conditions. Treatment efficacy and the effect of culture on treatment response were assessed using measures of emotional and decisional forgiveness across 3 time periods.

RESULTS

Students in the treatment condition reported greater improvement in emotional forgiveness, but not decisional forgiveness, relative to those in the waitlist condition. Gains were maintained at a 1-week follow-up. Although culture did not moderate the effect of treatment, a main effect of culture on emotional forgiveness and marginally significant interaction effect of culture on decisional forgiveness were found.

CONCLUSION

The REACH Forgiveness intervention was efficacious for college students from different cultural backgrounds when conducted in the United States. However, some evidence may warrant development of culturally adapted forgiveness interventions.

Primary cardiac lymphoma causing right atrial occlusion

Primary cardiac lymphomas (PCL) are extremely rare, and diffuse large B-cell lymphoma is a highly aggressive subtype. We report a case that was initially diagnosed as chronic right heart dysfunction. Detailed investigations revealed a large lobulated tumour occluding the right atrium, infiltrating the inter-atrial septum, the roof of the left atrium, and the aortic root. Despite adequate surgical debulking and initial successful tricuspid annuloplasty, the patient succumbed to multi-organ failure. Pathological analysis of the resected tumour confirmed a diffuse large B-cell lymphoma with a proliferation rate of 100%. What is unique about this case is the size of this rare cardiac tumour, which we believe to be one of the largest described in the literature for a purely intra-cardiac PCL, its aggressive growth rate, and the relatively mild symptomatology until a late stage of the disease.

A narrow and highly significant linkage signal for severe bipolar disorder in the chromosome 5q33 region in Latin American pedigrees

We previously reported linkage of bipolar disorder to 5q33-q34 in families from two closely related population isolates, the Central Valley of Costa Rica (CVCR) and Antioquia, Colombia (CO). Here we present follow up results from fine-scale mapping in large CVCR and CO families segregating severe bipolar disorder, BP-I, and in 343 population trios/duos from CVCR and CO. Employing densely spaced SNPs to fine map the prior linkage peak region increases linkage evidence and clarifies the position of the putative BP-I locus. We performed two-point linkage analysis with 1134 SNPs in an approximately 9 Mb region between markers D5S410 and D5S422. Combining pedigrees from CVCR and CO yields a LOD score of 4.9 at SNP rs10035961. Two other SNPs (rs7721142 and rs1422795) within the same 94 kb region also displayed LOD scores greater than 4. This linkage peak coincides with our prior microsatellite results and suggests a narrowed BP-I susceptibility regions in these families. To investigate if the locus implicated in the familial form of BP-I also contributes to disease risk in the population, we followed up the family results with association analysis in duo and trio samples, obtaining signals within 2 Mb of the peak linkage signal in the pedigrees; rs12523547 and rs267015 (P = 0.00004 and 0.00016, respectively) in the CO sample and rs244960 in the CVCR sample and the combined sample, with P = 0.00032 and 0.00016, respectively. It remains unclear whether these association results reflect the same locus contributing to BP susceptibility within the extended pedigrees.

Therapeutic drug monitoring of mycophenolic acid in kidney transplant patients: a abbreviated sampling strategy

Mycophenolic acid (MPA) levels have demonstrated a good correlation with clinical outcomes, but with great pharmacokinetic variability between patients. Therapeutic drug monitoring (TDM) is recommended to include a 12-hour area under the concentration-time curve (AUC). Since full AUC estimates are not practical for routine monitoring, limited sampling strategies have been suggested. We evaluated MPA pharmacokinetics in 18 stable renal transplant patients receiving mycophenolate mofetil (MMF) as part of their immunosuppressive therapy. The correlation between measured and estimated AUC was assessed using 4 different sparse sampling algorithms. The mean values for C(0) and AUC(0-6h) were 1.8 +/- 1.2 mg/L and 31.1 +/- 14.8 mg*h/L, respectively. The dose-corrected AUC(0-6h) was 35.4 +/- 17.9 mg*h/L. Regarding the single time points, C(0) showed a low correlation with AUC(0-6h) (r(2) = .34); C(1.5), the best correlation (r(2) = .72); and C(3), the worst (r(2) = .07). Sparse sample algorithms used to estimate 12-hour AUC including C(0), C(1), C(2), C(3), C(4), and/or C(6) showed a good correlation with the calculated AUC(0-6) (r(2) = .81-.96). The algorithm that used C(0), C(1), C(2), and C(4) showed the best correlation, but we also found a good correlation (r(2) = .91) with C(0), C(1), and C(2). Based on these results, we have suggested using the 3-point algorithm (C(0), C(1), and C(2)) for MPA TDM in stable renal transplant patients due to the good correlation with drug exposure and better functionality than an algorithm using a 4-hour postdose measurement.

Bonner sphere neutron spectrometry at nuclear workplaces in the framework of the EVIDOS project

The Institute for Radiological protection and Nuclear Safety was engaged in the EC funded EVIDOS project to provide reference spectrometry data using its Bonner sphere system. The data were processed by means of two unfolding codes, NUBAY and GRAVEL, both provided by the Physikalisch-Technische Bundesanstalt. The NUBAY program, based on Bayesian parameter estimation methods, assumes a parameterised spectrum and provides posterior probability distributions for the parameters. The code GRAVEL, an iterative algorithm based on SAND-II, was used with various default spectra, among them the NUBAY solution. The BS measurements were used to establish the neutron fluence energy distributions and reference values for the neutron ambient dose equivalent. As this quantity depends strongly on the high energy neutrons, a sensitivity analysis was done by unfolding the BS data with GRAVEL using the NUBAY solution spectrum as default with various changes in the parameters of the high energy peak. This new method of analysing Bonner sphere data allowed the determination of reliable neutron spectra, as well as a very good estimate of the corresponding integral quantities with small associated uncertainties.

Monte Carlo calculations and validation of a gold foil-based Bonner sphere system

The Grup de Física de les Radiacions (GFR) of the Universitat Autònoma de Barcelona (UAB), in collaboration with the Institute for Radiological Protection and Nuclear Safety (IRSN), has developed a passive Bonner sphere system (UAB-BSS), with gold foils as thermal neutron detectors, for application in pulsed neutron fields or in mixed neutron-photon fields with high photon intensities. In such fields, active devices suffer from saturation and dead-time effects. The MCNPX Monte-Carlo code has been used to determine the response to neutrons of different energies of each polyethylene sphere belonging to the BSS. The passive UAB-BSS system was characterised with the ISO (252)Cf reference source at the IRSN facilities. The energy distribution of the reference source neutron fluence was folded with the response functions for comparison with the experimental data. A good agreement between the experimental and calculated count rates was found.

Workplace characterisation in case of rail transport of radioactive materials

IRSN has been asked by SNCF (French Railways) to carry out measurements in order to establish the values of ambient dose equivalents H*(10) in the vicinity of shipments of radioactive materials to assess the external exposure to ionising radiation to which employees may be subjected during the carriage of radioactive goods. Detailed dosimetric characterisations of the wagons have been made and the external exposure at different stages of the work that is done by the employees have been measured in terms of H*(10). For the study presented in this paper, and corresponding to a used fuel shipment composed of UO2 and UO2-PuO2, it has been observed that the photon and neutron doses are very similar. In addition, the order of magnitude of the total dose integrated by an employee who would carry out 100 times the series of essential operational tasks, has been found to be approximately 250 microSv. This value is compared with those observed for other previously investigated shipments involving the exposure to photon fields only.

Set-up of a passive Bonner sphere system for neutron spectrometry at mixed fields with predominant photon component based on activation detector

A passive Bonner sphere system (BSS), based on thermal neutron activation detectors, was developed to perform neutron spectrometry in pulsed and very intense (n-gamma) fields with predominant photon component, as those produced by high energy (>10 MV) medical linear electron accelerators. In this paper, a description of the new system is presented together with an experimental characterisation of a portable Sodium Iodide (NaI) detector and a fixed high-purity Germanium one, both used to measure the induced gamma-activity of the activated materials, respectively, in situ and in the laboratory. The choice of the activated materials is justified according to pre-established practical considerations and physical criteria. The response functions of the entire passive BSS were calculated using the MCNPX code. A preliminary experimental validation with a bare (252)Cf source is given as well.

Neutron spectrometry around the VENUS reactor using Monte Carlo simulations and Bonner spheres measurements

This paper presents the assessment of the neutron field near the VENUS reactor, particularly in areas near the reactor shielding where operators are frequently present during a reactor run. To obtain reference spectra in the area of interest, MCNPX simulations were performed. Reference spectrometry was also performed using a Bonner spheres system. The outcome of both calculations and measurements is compared.

Characterization of neutron field in a NPP workplace

At the Krsko Nuclear Power Plant (NPP), albedo dosimeters are used for personal neutron dosimetry. Spectrometric measurements allow determination of reference dosimetric values of realistic neutron fields to be used for calibration of albedo dosimeters. The Laboratory for Neutron Metrology and Dosimetry from the Institute for Radiological Protection and Nuclear Safety (IRSN) was in charge of characterising neutron fields in the plant at two representative points with high neutron and gamma dose rate. Calibration of the dosimeters in the workplace used to be performed only by a spherical survey meter. Based on the reference dosimetric values, the Plant Dosimetry Laboratory has verified the response of albedo dosimeters.

Evaluation of individual monitoring in mixed neutron/photon fields: mid-term results from the EVIDOS project

EVIDOS is an EC sponsored project that aims at an evaluation and improvement of radiation protection dosimetry in mixed neutron/photon fields. This is performed through spectrometric and dosimetric investigations during different measurement campaigns in representative workplaces of the nuclear industry. The performance of routine and, in particular, novel personal dosemeters and survey instruments is tested in selected workplace fields. Reference values for the dose equivalent quantities, H(*)(10) and H(p)(10) and the effective dose E, are determined using different spectrometers that provide the energy distribution of the neutron fluence and using newly developed devices that determine the energy and directional distribution of the neutron fluence. The EVIDOS project has passed the mid-term, and three measurement campaigns have been performed. This paper will give an overview and some new results from the third campaign that was held in Mol (Belgium), around the research reactor VENUS and in the MOX producing plant of Belgonucléaire.

Performance of the electronic personal dosemeter for neutron 'Saphydose-N' at different workplaces of nuclear facilities

This paper mainly aims at presenting the measurements and the results obtained with the electronic personal neutron dosemeter Saphydose-N at different facilities. Three campaigns were led in the frame of the European contract EVIDOS ('Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields'). The first one consisted in the measurements at the IRSN French research laboratory in reference neutron fields generated by a thermal facility (SIGMA), radionuclide ISO sources ((241)AmBe; (252)Cf; (252)Cf(D(2)O)\Cd) and a realistic spectrum (CANEL/T400). The second one was performed at the Krümmel Nuclear Power Plant (Germany) close to the boiling water reactor and to a spent fuel transport cask. The third one was realised at Mol (Belgium), at the VENUS Research Reactor and at Belgonucléaire, a fuel processing factory.