Long-term diffusion experiment at Mont Terri: first results from field and laboratory data

The diffusion of radionuclides is an important safety aspect for nuclear waste disposal in argillaceous host rocks. A long-term diffusion experiment, termed DI-A, is being carried out at the Mont Terri Rock Laboratory in the Opalinus Clay formation. The aim of this experiment is the understanding of the migration and sorption behaviour of cationic and anionic species in consolidated clays. This study reports on the experimental layout and the first results obtained from the DI-A experiment, which include the investigation of HTO, Na-22(+), Cs+, and I- migration during a period of 1 year by analysing these tracers in the water circulating in the borehole. In addition, results obtained from through-diffusion experiments on small-sized samples with HTO, I-, and Cl-36(-) are presented. The decrease of tracer concentrations in the borehole is fastest for Cs+, followed by Na-22(+), HTO, and finally I-. The chemical composition of the artificial pore water in the borehole shows very little variation with time, thus indicating almost no chemical disturbance around the borehole. Through-diffusion experiments in the laboratory that were performed parallel to the bedding plane with two different methods yielded effective diffusion coefficients for HTO of 4-5 X 10(-11) m(2) s(-1) and significantly lower ones for anions Cl- and I- (0.7-1.6 X 10(-11) m(2) s(-1)). The results indicate the importance of anion exclusion effects arising from the negatively charged clay surfaces. Furthermore, they demonstrate the anisotropic diffusion properties of the clay formation with significantly increased diffusion rates parallel to bedding relative to the perpendicular direction. The tracer data of the in situ experiment were successfully described with 2D diffusion models using diffusion and sorption parameters obtained from the above mentioned and other laboratory studies. The modelling results indicate that HTO and I- diffused with no retardation. The retardation of Na+ and Cs+ could be described by empirical sorption expressions from previously derived batch sorption (Cs+) or diffusion (Na+) experiments. Overall, the obtained results demonstrate the feasibility of the technical concept to study the diffusion of nonsorbing and sorbing tracers in consolidated clays. (C) 2004 Elsevier B.V. All rights reserved.

A case of EDTA-dependent pseudothrombocytopenia: simple recognition of an underdiagnosed and misleading phenomenon

1. BMC Clin Pathol. 2014 May 1;14:19. doi: 10.1186/1472-6890-14-19. eCollection 2014. A case of EDTA-dependent pseudothrombocytopenia: simple recognition of an underdiagnosed and misleading phenomenon. Nagler M, Keller P, Siegrist D, Alberio L. Author information: Department of Hematology and Central Hematology Laboratory, Inselspital University Hospital and University of Berne, CH-3010 Berne, Switzerland. BACKGROUND: EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a common laboratory phenomenon with a prevalence ranging from 0.1-2% in hospitalized patients to 15-17% in outpatients evaluated for isolated thrombocytopenia. Despite its harmlessness, EDTA-PTCP frequently leads to time-consuming, costly and even invasive diagnostic investigations. EDTA-PTCP is often overlooked because blood smears are not evaluated visually in routine practice and histograms as well as warning flags of hematology analyzers are not interpreted correctly. Nonetheless, EDTA-PTCP may be diagnosed easily even by general practitioners without any experiences in blood film examinations. This is the first report illustrating the typical patterns of a platelet (PLT) and white blood cell (WBC) histograms of hematology analyzers. CASE PRESENTATION: A 37-year-old female patient of Caucasian origin was referred with suspected acute leukemia and the crew of the emergency unit arranged extensive investigations for work-up. However, examination of EDTA blood sample revealed atypical lymphocytes and an isolated thrombocytopenia together with typical patterns of WBC and PLT histograms: a serrated curve of the platelet histogram and a peculiar peak on the left side of the WBC histogram. EDTA-PTCP was confirmed by a normal platelet count when examining citrated blood. CONCLUSION: Awareness of typical PLT and WBC patterns may alert to the presence of EDTA-PTCP in routine laboratory practice helping to avoid unnecessary investigations and over-treatment. PMCID: PMC4012027 PMID: 24808761 [PubMed]

Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations — Initial experience

AIM: To evaluate the influence of locally active Crohn's disease on systemic small-bowel motility in patients with chronic Crohn's disease compared to healthy individuals. MATERIAL AND METHODS: Fifteen healthy individuals (11 men, four women; mean age 37 years) and 20 patients with histopathologically proven active (n = 15; 10 women, 5 men; mean age 45 years) or chronic (n = 5; four women, one man; mean age 48 years) Crohn's disease were included in this institutional review board-approved, retrospective study. Magnetic resonance imaging (MRI; 1.5 T) was performed after standardized preparation. Two-dimensional (2D) cine sequences for motility acquisition were performed in apnoea (27 s). Motility assessment was performed using dedicated software in three randomly chosen areas of the small-bowel outside known Crohn's disease-affected hotspots. The main quantitative characteristics (frequency, amplitude, occlusion rate) were compared using Student's t-test and one-way analysis of variance (ANOVA). RESULTS: Three randomly chosen segments were analysed in each participant. Patients with active Crohn's disease had significantly (p < 0.05) reduced contraction frequencies (active Crohn's disease: 2.86/min; chronic: 4.14/min; healthy: 4.53/min) and luminal occlusion rates (active: 0.43; chronic: 0.70; healthy: 0.73) compared to healthy individuals and patients with chronic Crohn's disease. Contraction amplitudes were significantly reduced during active Crohn's disease (6.71 mm) compared to healthy participants (10.14 mm), but this only reached borderline significance in comparison to chronic Crohn's disease (8.87 mm). Mean bowel lumen diameter was significantly (p = 0.04) higher in patients with active Crohn's disease (16.91 mm) compared to healthy participants (14.79 mm) but not in comparison to patients with chronic Crohn's disease (13.68). CONCLUSION: The findings of the present study suggest that local inflammatory activity of small-bowel segments in patients with active Crohn's disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohn's disease.

The cyclotron laboratory and the RFQ accelerator in Bern

Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

14C Analysis and Sample Preparation at the New Bern Laboratory for the Analysis of Radiocarbon with AMS (LARA)

The University of Bern has set up the new Laboratory for the Analysis of Radiocarbon with AMS (LARA) equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) to continue its long history of 14C analysis based on conventional counting. The new laboratory is designated to provide routine 14C dating for archaeology, climate research, and other disciplines at the University of Bern and to develop new analytical systems coupled to the gas ion source for 14C analysis of specific compounds or compound classes with specific physical properties. Measurements of reference standards and wood samples dated by dendrochronology demonstrate the quality of the 14C analyses performed at the new laboratory.

Increased sleep need and daytime sleepiness 6 months after traumatic brain injury: a prospective controlled clinical trial.

Post-traumatic sleep-wake disturbances are common after acute traumatic brain injury. Increased sleep need per 24 h and excessive daytime sleepiness are among the most prevalent post-traumatic sleep disorders and impair quality of life of trauma patients. Nevertheless, the relation between traumatic brain injury and sleep outcome, but also the link between post-traumatic sleep problems and clinical measures in the acute phase after traumatic brain injury has so far not been addressed in a controlled and prospective approach. We therefore performed a prospective controlled clinical study to examine (i) sleep-wake outcome after traumatic brain injury; and (ii) to screen for clinical and laboratory predictors of poor sleep-wake outcome after acute traumatic brain injury. Forty-two of 60 included patients with first-ever traumatic brain injury were available for follow-up examinations. Six months after trauma, the average sleep need per 24 h as assessed by actigraphy was markedly increased in patients as compared to controls (8.3 ± 1.1 h versus 7.1 ± 0.8 h, P < 0.0001). Objective daytime sleepiness was found in 57% of trauma patients and 19% of healthy subjects, and the average sleep latency in patients was reduced to 8.7 ± 4.6 min (12.1 ± 4.7 min in controls, P = 0.0009). Patients, but not controls, markedly underestimated both excessive sleep need and excessive daytime sleepiness when assessed only by subjective means, emphasizing the unreliability of self-assessment of increased sleep propensity in traumatic brain injury patients. At polysomnography, slow wave sleep after traumatic brain injury was more consolidated. The most important risk factor for developing increased sleep need after traumatic brain injury was the presence of an intracranial haemorrhage. In conclusion, we provide controlled and objective evidence for a direct relation between sleep-wake disturbances and traumatic brain injury, and for clinically significant underestimation of post-traumatic sleep-wake disturbances by trauma patients.

Evaluation of Cage Designs and Feeding Regimes for Honey Bee (Hymenoptera: Apidae) Laboratory Experiments

The aim of this study was to improve cage systems for maintaining adult honey bee (Apis mellifera L.) workers under in vitro laboratory conditions. To achieve this goal, we experimentally evaluated the impact of different cages, developed by scientists of the international research network COLOSS (Prevention of honey bee COlony LOSSes), on the physiology and survival of honey bees. We identified three cages that promoted good survival of honey bees. The bees from cages that exhibited greater survival had relatively lower titers of deformed wing virus, suggesting that deformed wing virus is a significant marker reflecting stress level and health status of the host. We also determined that a leak- and drip-proof feeder was an integral part of a cage system and a feeder modified from a 20-ml plastic syringe displayed the best result in providing steady food supply to bees. Finally, we also demonstrated that the addition of protein to the bees' diet could significantly increase the level ofvitellogenin gene expression and improve bees' survival. This international collaborative study represents a critical step toward improvement of cage designs and feeding regimes for honey bee laboratory experiments.

Laboratory recommendations for scoring deep molecular responses following treatment for chronic myeloid leukemia.

Treatment of chronic myeloid leukemia (CML) with tyrosine kinase inhibitors has advanced to a stage where many patients achieve very low or undetectable levels of disease. Remarkably, some of these patients remain in sustained remission when treatment is withdrawn, suggesting that they may be at least operationally cured of their disease. Accurate definition of deep molecular responses (MRs) is therefore increasingly important for optimal patient management and comparison of independent data sets. We previously published proposals for broad standardized definitions of MR at different levels of sensitivity. Here we present detailed laboratory recommendations, developed as part of the European Treatment and Outcome Study for CML (EUTOS), to enable testing laboratories to score MR in a reproducible manner for CML patients expressing the most common BCR-ABL1 variants.Leukemia advance online publication, 27 February 2015; doi:10.1038/leu.2015.29.

Laboratory observations and simulations of phase reddening

The visible reflectance spectrum of many Solar System bodies changes with changing viewing geometry for reasons not fully understood. It is often observed to redden (increasing spectral slope) with increasing solar phase angle, an effect known as phase reddening. Only once, in an observation of the martian surface by the Viking 1 lander, was reddening observed up to a certain phase angle with bluing beyond, making the reflectance ratio as a function of phase angle shaped like an arch. However, in laboratory experiments this arch-shape is frequently encountered. To investigate this, we measured the bidirectional reflectance of particulate samples of several common rock types in the 400–1000 nm wavelength range and performed ray-tracing simulations. We confirm the occurrence of the arch for surfaces that are forward scattering, i.e. are composed of semi-transparent particles and are smooth on the scale of the particles, and for which the reflectance increases from the lower to the higher wavelength in the reflectance ratio. The arch shape is reproduced by the simulations, which assume a smooth surface. However, surface roughness on the scale of the particles, such as the Hapke and van Horn (Hapke, B., van Horn, H. [1963]. J. Geophys. Res. 68, 4545–4570) fairy castles that can spontaneously form when sprinkling a fine powder, leads to monotonic reddening. A further consequence of this form of microscopic roughness (being indistinct without the use of a microscope) is a flattening of the disk function at visible wavelengths, i.e. Lommel–Seeliger-type scattering. The experiments further reveal monotonic reddening for reflectance ratios at near-IR wavelengths. The simulations fail to reproduce this particular reddening, and we suspect that it results from roughness on the surface of the particles. Given that the regolith of atmosphereless Solar System bodies is composed of small particles, our results indicate that the prevalence of monotonic reddening and Lommel–Seeliger-type scattering for these bodies results from microscopic roughness, both in the form of structures built by the particles and roughness on the surface of the particles themselves. It follows from the singular Viking 1 observation that the surface in front of the lander was composed of semi-transparent particles, and was smooth on the scale of the particle size.

The impact of environmental enrichment on the outcome variability and scientific validity of laboratory animal studies.

It has been widely accepted for some time that species-appropriate environmental enrichment is important for the welfare of research animals, but its impact on research data initially received little attention. This has now changed, as the use of enrichment as one element of routine husbandry has expanded. In addition to its use in the care of larger research animals, such as nonhuman primates, it is now being used to improve the environments of small research animals, such as rodents, which are used in significantly greater numbers and in a wide variety of studies. Concern has been expressed that enrichment negatively affects both experimental validity and reproducibility. However, when a concise definition of enrichment is used, with a sound understanding of the biology and behaviour of the animal as well as the research constraints, it becomes clear that the welfare of research animals can be enhanced through environmental enrichment without compromising their purpose. Indeed, it is shown that the converse is true: the provision of suitable enrichment enhances the well-being of the animal, thereby refining the animal model and improving the research data. Thus, the argument is made that both the validity and reproducibility of the research are enhanced when proper consideration is given to the research animal's living environment and the animal's opportunities to express species-typical behaviours.