Evaluation of individual dosimetry in mixed neutron and photon radiation fields (EVIDOS). Part II: Conclusions and recommendations

The paper presents the main conclusions and recommendations derived from the EVIDOS project, which is supported by the European Commission within the 5th Framework Programme. EVIDOS aims at evaluating state of the art neutron dosimetry techniques in representative workplaces of the nuclear industry with complex mixed neutron-photon radiation fields. This analysis complements a series of individual papers which present detailed results and it summarises the main findings from a practical point of view. Conclusions and recommendations are given concerning characterisation of radiation fields, methods to derive radiation protection quantities and dosemeter results.

Application of workplace correction factors to dosemeter results for the assessment of personal doses at nuclear facilities

Ratios of H(p)(10) and H*(10) were determined with reference instruments in a number of workplace fields within the nuclear industry and used to derive workplace-specific correction factors. When commercial survey meter results together with these factors were applied to the results of the locally used personal dosemeters their results improved and became within 0.7 and 1.7 of the reference values or better depending on the response of the survey meter. A similar result was obtained when a correction was determined with a prototype reference instrument for H(p)(10) after adjustment of its response. Commercially available survey instruments both for photon and neutron H*(10) measurements agreed with the reference instruments in most cases to within 0.5-1.5. Those conclusions are derived from results reported within the EC supported EVIDOS contract.

Direction distributions of neutrons and reference values of the personal dose equivalent in workplace fields

Within the EC project EVIDOS, double-differential (energy and direction) fluence spectra were determined by means of novel direction spectrometers. By folding the spectra with fluence-to-dose equivalent conversion coefficients, contributions to H*(10) for 14 directions, and values of the personal dose equivalent Hp(10) and the effective dose E for 6 directions of a person's orientation in the field were determined. The results of the measurements and calculations obtained within the EVIDOS project in workplace fields in nuclear installations in Europe, i.e., at Krümmel (boiling water reactor and transport cask), at Mol (Venus research reactor and fuel facility Belgonucléaire) and at Ringhals (pressurised reactor and transport cask) are presented.

Summary of personal neutron dosemeter results obtained within the EVIDOS project

Within the EC project EVIDOS ('Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields'), different types of active neutron personal dosemeters (and some passive ones) were tested in workplace fields at nuclear installations in Europe. The results of the measurements which have been performed up to now are summarised and compared to our currently best estimates of the personal dose equivalent Hp(10). Under- and over-readings by more than a factor of two for the same dosemeter in different workplace fields indicate that in most cases the use of field-specific correction factors is required.

Characterisation of mixed neutron photon workplace fields at nuclear facilities by spectrometry (energy and direction) within the EVIDOS project

Within the EC project EVIDOS, 17 different mixed neutron-photon workplace fields at nuclear facilities (boiling water reactor, pressurised water reactor, research reactor, fuel processing, storage of spent fuel) were characterised using conventional Bonner sphere spectrometry and newly developed direction spectrometers. The results of the analysis, using Bayesian parameter estimation methods and different unfolding codes, some of them especially adapted to simultaneously unfold energy and direction distributions of the neutron fluence, showed that neutron spectra differed strongly at the different places, both in energy and direction distribution. The implication of the results for the determination of reference values for radiation protection quantities (ambient dose equivalent, personal dose equivalent and effective dose) and the related uncertainties are discussed.

Evaluation of individual dosimetry in mixed neutron and photon radiation fields (EVIDOS). Part I: Scope and methods of the project

Supported by the European Commission, the EVIDOS project started in November 2001 with the broad goal of evaluating state of the art dosimetry techniques in representative workplaces of the nuclear industry. Seven European institutes joined efforts with end users at nuclear power plants, at fuel processing and reprocessing plants, and at transport and storage facilities. A comprehensive programme was devised to evaluate capabilities and limitations of standard and innovative personal dosemeters in relation to the mixed neutron-photon fields of concern to the nuclear industry. This paper describes the criteria behind the selection of dosimetry techniques and workplaces that were analysed, as well as the organisation of the measurement campaigns. Particular emphasis was placed on the evaluation of a variety of electronic personal dosemeters, either commercially available or previously developed by the partners. The estimates provided by these personal dosemeters were compared to reference values of dose equivalent quantities derived from spectrometry and fluence-to-dose equivalent conversion coefficients. Spectrometry was performed both with conventional multisphere and with some original instrumentation providing energy and direction resolution, based on silicon detectors and superheated drop detectors mounted on or in spherical moderators. The results were collected in a large, searchable database and are intended to be used in the harmonisation of dosimetric procedures for mixed radiation fields and for the approval of dosimetry services in Europe.

Acute weight loss followed by an aggressive nutritional recovery strategy has little impact on on-water rowing performance

OBJECTIVES

To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing.

METHODS

Competitive rowers (n = 17) undertook three on-water 1800 m time trials under cool conditions (mean (SD) temperature 8.4 (2.0) degrees C), each separated by 48 hours. No weight limit was imposed for the first time trial--that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT(-4%)). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT(-4%), 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials.

RESULTS

WT(-4%) had only a small and statistically non-significant effect on the on-water time trial performance (mean 1.0 second, 95% confidence interval (CI) -0.9 to 2.8; p = 0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT(-4%) compared with UNR (-9.2%, 95% CI -12.8% to -5.6%; p<0.001).

CONCLUSIONS

Acute weight loss of up to 4% over 24 hours, when combined with aggressive nutritional recovery strategies, can be undertaken with minimal impact on on-water rowing performance, at least in cool conditions.

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.

Electronic neutron personal dosemeters: their performance in mixed radiation fields in nuclear power plants

This work describes spectral distributions of neutrons obtained as function of energy and direction at four workplace fields at the Krümmel reactor in Germany. Values of personal dose equivalent H(p)(10) and effective dose E are determined for different directions of a person's orientation in these fields and readings of personal neutron dosemeters--especially electronic dosemeters--are discussed with respect to H(p)(10) and E.

Individual neutron monitoring in workplaces with mixed neutron/photon radiation

EVIDOS ('evaluation of individual dosimetry in mixed neutron and photon radiation fields') is an European Commission (EC)-sponsored project that aims at a significant improvement of radiation protection dosimetry in mixed neutron/photon fields via spectrometric and dosimetric investigations in representative workplaces of the nuclear industry. In particular, new spectrometry methods are developed that provide the energy and direction distribution of the neutron fluence from which the reference dosimetric quantities are derived and compared to the readings of dosemeters. The final results of the project will be a comprehensive set of spectrometric and dosimetric data for the workplaces and an analysis of the performance of dosemeters, including novel electronic dosemeters. This paper gives an overview of the project and focuses on the results from measurements performed in calibration fields with broad energy distributions (simulated workplace fields) and on the first results from workplaces in the nuclear industry, inside a boiling water reactor and around a spent fuel transport cask.

The structure of phosphorylated GSK-3beta complexed with a peptide, FRATtide, that inhibits beta-catenin phosphorylation

BACKGROUND

Glycogen synthase kinase-3 (GSK-3) sequentially phosphorylates four serine residues on glycogen synthase (GS), in the sequence SxxxSxxxSxxx-SxxxS(p), by recognizing and phosphorylating the first serine in the sequence motif SxxxS(P) (where S(p) represents a phosphoserine). FRATtide (a peptide derived from a GSK-3 binding protein) binds to GSK-3 and blocks GSK-3 from interacting with Axin. This inhibits the Axin-dependent phosphorylation of beta-catenin by GSK-3.

RESULTS

Structures of uncomplexed Tyr216 phosphorylated GSK-3beta and of its complex with a peptide and a sulfate ion both show the activation loop adopting a conformation similar to that in the phosphorylated and active forms of the related kinases CDK2 and ERK2. The sulfate ion, adjacent to Val214 on the activation loop, represents the binding site for the phosphoserine residue on 'primed' substrates. The peptide FRATtide forms a helix-turn-helix motif in binding to the C-terminal lobe of the kinase domain; the FRATtide binding site is close to, but does not obstruct, the substrate binding channel of GSK-3. FRATtide (and FRAT1) does not inhibit the activity of GSK-3 toward GS.

CONCLUSIONS

The Axin binding site on GSK-3 presumably overlaps with that for FRATtide; its proximity to the active site explains how Axin may act as a scaffold protein promoting beta-catenin phosphorylation. Tyrosine 216 phosphorylation can induce an active conformation in the activation loop. Pre-phosphorylated substrate peptides can be modeled into the active site of the enzyme, with the P1 residue occupying a pocket partially formed by phosphotyrosine 216 and the P4 phosphoserine occupying the 'primed' binding site.

The production of nerve growth factor by human bladder smooth muscle cells in vivo and in vitro

OBJECTIVE

To measure the concentrations of nerve growth factor (NGF) in tissue biopsies taken from subjects with a normal bladder and from patients diagnosed to have idiopathic detrusor instability (associated with a reduction in the density of motor nerves), and to use an in vitro model to study the mechanisms of NGF expression.

MATERIALS AND METHODS

Biopsy specimens were obtained during endoscopic and open surgery from patients undergoing routine bladder surgery. The patients were divided into two categories based upon urodynamic characterization. The NGF content in samples from 11 normal bladders and seven idiopathic unstable bladders were measured using an enzyme-linked immunosorbent assay. The mechanisms influencing net NGF production were explored using detrusor cells in vitro.

RESULTS

The mean (SEM) NGF content was significantly higher in unstable tissues, at 0.96 (0.05) pg/microg protein, than in the normal bladder, at 0.53 (0.05) pg/microg protein. In the cell model, acetylcholine (10 micromol/L), noradrenaline (1 and 10 micromol/L) and ATP (1 micromol/L) caused a significant increase in net NGF production; acetylcholine at 1 micromol/L had no effect. Direct stimulation of protein kinase C (PKC) by phorbol ester (33 ng/mL) or elevation of cAMP using forskolin (10 micromol/L) increased NGF, suggesting that at least two intracellular pathways (PKC- and PKA-dependent) are involved. The expression of c-Fos was increased by phorbol 12-myristate 13-acetate added before NGF, suggesting that c-Fos may be involved in regulating NGF production.

CONCLUSION

These data suggest a role for NGF in the physiology and pathophysiology of the human bladder, and indicate some of the possible mechanisms which might regulate NGF production.

A low energy green hospital

This paper describes a unique project to monitor and evaluate a range of energy saving techniques and measures installed in a hospital in the North East of England. The aims of the project were: to test theoretical studies that had identified measures that could achieve savings in energy usage in hospitals to test the economic viability of the energy saving measures and determine whether they are suitable for replication in new, as well as existing hospitals to provide experience of energy saving techniques and measures in an operational hospital to provide a comprehensive database of information on how energy is used in hospitals The results from the project show that it is possible to significantly reduce the energy consumption in hospitals. Over the three year monitoring period, it is calculated that the hospital used an average of 39% less energy per annum than a comparable, conventional hospital. This energy saving also represents a reduction in CO2 emissions of 1900 tonnes per annum. The project has provided reliable data and information that has contributed to a much better understanding of how energy is used in hospitals.

Determination of fluconazole in human plasma by micellar electrokinetic capillary chromatography with detection at 190 nm

The determination of fluconazole (Diflucan) in human plasma by micellar electrokinetic capillary chromatography (MECC) with on-column UV absorption detection at 190 nm from primary, deproteinized and extracted plasma samples is discussed. Direct injection of plain plasma or of the supernatant after protein precipitation with acetonitrile is shown to permit the determination of fluconazole drug levels of > 5 micrograms/ml only. With liquid-liquid extraction employing dichloromethane, the detection limit is about 1 microgram/ml. After extraction using disposable solid-phase C18 cartridges and 1 ml of plasma, however, drug levels as low as 100 ng/ml can be determined unambiguously. Calibration graphs between 0.125-25.0 micrograms/ml (seven data points) are shown to be linear, with a regression coefficient r > 0.999. for fluconazole plasma levels of 5 micrograms/ml, intra-day and inter-day imprecisions (n = 10) are about 2 and 5%, respectively. Using the same solid-phase extraction procedure, 44 fluconazole plasma levels that were determined by MECC are shown to agree well with those obtained by HPLC and elucidated pharmacokinetic data compare well with those found in the literature. The advantages of using MECC instead of HPLC for the determination of fluconazole plasma levels and pharmacokinetics are the high resolution efficiency, low-cost capillary columns and the small consumption of inexpensive and environmentally friendly chemicals.

Baromedicine today--rational uses of hyperbaric oxygen therapy

Compressed air, and more recently hyperbaric oxygen, have been used and misused in medical treatment for more than 300 years. Advances in physiology have led to rational protocols for hyperbaric oxygen use. Hyperbaric oxygen will enhance wound healing by fibroblast and capillary proliferation, suppress infection, reduce edema, reverse CNS damage from carbon monoxide and cyanide poisoning, and reduce clostridial alpha toxins. Monoplace and multiplace chambers are used for treatment during which EKG and oxygen tissue monitoring, as well as hemodynamic and respiratory support, can be continued, iatrogenic air embolism and diving decompression sickness demand immediate treatment. Investigative uses of adjunct therapy for several other clinical problems include treatment of MS, acute spinal cord injuries, and acute MI. Specific indications agreed on by the Undersea and Hyperbaric Medicine Society are recognized by most third-party payers including Medicare, Champus, and HMSA. Hyperbaric medicine remains a fertile area for basic physiologic investigation and outcomes research.

Phylogeny of the ammonia-producing ruminal bacteria Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum sp. nov

In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal OrthoticsSelective Use in Rehabilitation of Vertebral Osteoporosis

Symptomatic involutional osteoporosis is a significant clinical problem. The prevalence of radiographic vertebral compression fractures (VCF) reached 26% in a rigorous population study of men and women more than 50 years old.1 However, only an estimated 8% of the total affected population actually seek medical attention.2-4 Investigations of effective medical therapy have been extensive, while sound studies of the physical therapeutic measures have been relatively few.5-10Pain and loss of functional mobility result from this disorder. Kyphosis, with or without vertebral compression fracture, is the major structural culprit that produces these disabling clinical problems. Spinal orthoses are used clinically for mechanical support and pain relief of osteoporosis.5,11-13 However, little research exists on the efficacy of orthotics in osteoporosis. This article provides a practical approach to guide the practitioner in orthotic selection for selected patients. New concepts presented may stimulate further research interest and more appropriate orthosis prescription. By focusing on level of fracture, biomechanical deficits, and physiatric team mangement, the end product can better satisfy the patient.

4-Methyltrityl (Mtt): a new protecting group for the side chain protection of Asn and Gln in solid-phase peptide synthesis

The trityl group was recently introduced for the protection of the side chain carboxamide function of asparagine and glutamine. The 4-methyltrityl (Mtt) group, a structural modification of trityl, is presented here and allows more rapid cleavage from the protected peptides. Procedures for the introduction of the group and comparative cleavage reactions are also presented.