A 10B-based neutron detector with stacked Multiwire Proportional Counters and macrostructured cathodes

We present the results of the measurements of the detection efficiency for a 4.7 \r{A} neutron beam incident upon a detector incorporating a stack of up to five MultiWire Proportional Counters (MWPC) with Boron-coated cathodes. The cathodes were made of Aluminum and had a surface exhibiting millimeter-deep V-shaped grooves of 45{\deg}, upon which the thin Boron film was deposited by DC magnetron sputtering. The incident neutrons interacting with the converter layer deposited on the sidewalls of the grooves have a higher capture probability, owing to the larger effective absorption film thickness. This leads to a higher overall detection efficiency for the grooved cathode when compared to a cathode with a flat surface. Both the experimental results and the predictions of the GEANT4 model suggests that a 5-counter detector stack with coated grooved cathodes has the same efficiency as a 7-counter stack with flat cathodes. The reduction in the number of counters in the stack without altering the detection efficiency will prove highly beneficial for large-area position-sensitive detectors for neutron scattering applications, for which the cost-effective manufacturing of the detector and associated readout electronics is an important objective. The proposed detector concept could be a technological option for one of the new chopper spectrometers and other instruments planned to be built at the future European Spallation Source in Sweden. These results with macrostructured cathodes generally apply not just to MWPCs but to other gaseous detectors as well.Comment: 14 pages, 9 figure

The new small-angle neutron scattering instrument SANS-1 at MLZ—characterization and first results

AbstractA thorough characterization of the key features of the new small-angle neutron scattering instrument SANS-1 at MLZ, a joint project of Technische Universität München and Helmholtz Zentrum Geesthacht, is presented. Measurements of the neutron beam profile, divergency and flux are given for various positions along the instrument including the sample position, and agree well with Monte Carlo simulations of SANS-1 using the program McStas. Secondly, the polarization option of SANS-1 is characterized for a broad wavelength band. A key feature of SANS-1 is the large accessible Q-range facilitated by the sideways movement of the detector. Particular attention is hence paid to the effects that arise due to large scattering angles on the detector where a standard cos3 solid angle correction is no longer applicable. Finally the performance of the instrument is characterized by a set of standard samples

Blood Chemistry, Acid- Base, Electrolyte, Blood Lactate Metabolism and Sleep at 3480 m in Mountain Marathon Runners

Altered blood chemistry, acid-base and electrolyte are suggested determinants of sleep disturbance, with frequent arousal at high altitude even in well and long-trained altitude marathon runners. In this sample of experienced altitude marathon runners with maximal aerobic power at sea level of 61.4 \ub1 2.7 ml/kg 121\u387min 121 we found that pO2 and percent of oxygen saturation (%SO2) were lower at 2050 m and 3480 m than at sea level; pO2 was higher after 38 - 41 hours than after 30 - 31 hours of acclimatization at 3480 m (P < 0.05). After ascent to 3480 m %SO2 decreased (P < 0.003). Compared to sea level values, pH increased at high altitude (P < 0.05) consistent with changes in pCO2 and [HCO3-] (P < 0.05). Nocturnal %SpaO2 at a sleeping altitude of 3480 m was lower (P < 0.05) than at sea level. At high altitude, the percent of wake (W) time and delay falling asleep (DFA) increased, whereas non-rapid eye movement sleep (N-REM), REM sleep and total sleep time (TST) decreased (P < 0.05). Simple regression analysis disclosed a significant correlation between the changes in TST and the percent of REM sleep and the changes in %SpaO2 recorded during sleep (P < 0.05). Simple regression analysis showed a positive correlation between the changes in pO2 at higher altitude and the percent of W and of TST (P < 0.05). The changes in pO2, tCO2 and [HCO3-] correlated negatively and significantly with the percent of REM sleep changes at high altitude (P < 0.05). The TST changes at high altitude correlated positively with the changes in pO2 and pH and correlated negatively with the changes in %SO2, pCO2, tCO2, and [HCO3-] (P < 0.05). The changes in the percent of W at high altitude correlated significantly and positively with the changes in bases excess [BE] at high altitude (P < 0.05). The changes in the percent of REM sleep correlated significantly and positively with the changes in [iCa++] and [BE] and negatively with the changes in buffered bases [BB] and [BEeffective] (P < 0.05). The change in the percent of NREM + REM sleep at high altitude correlated significantly and positively with the changes in [BE] and [BB] concentration (P < 0.05). The increase in DFA at high altitude correlated significantly and negatively with the changes in pCO2 and significantly and negatively with the changes in [K+] (P < 0.05). Simple regression analysis demonstrated that the changes in pH at high altitude correlated positively and significantly with the percent of W and the DFA and negatively with the percent of changes in NREM sleep, REM sleep, NREM + REM sleep (P < 0.05). The decrease in the TST at high altitude correlated significantly and negatively with the changes in pCO2, tCO2, [HCO3-]and [K+] (P < 0.05). Our data demonstrate that the arterialized ear lobe techniques we used for evaluating most of the changes in blood chemistry, acid-base, electrolyte and blood lactate metabolism are suitable for clinical and laboratory assessment and are important predictors of the quality and quantity of acclimatization and sleep at high altitude

Personalizing Cancer Pain Therapy: Insights from the Rational Use of Analgesics (RUA) Group

Introduction: A previous Delphi survey from the Rational Use of Analgesics (RUA) project involving Italian palliative care specialists revealed some discrepancies between current guidelines and clinical practice with a lack of consensus on items regarding the use of strong opioids in treating cancer pain. Those results represented the basis for a new Delphi study addressing a better approach to pain treatment in patients with cancer. Methods: The study consisted of a two-round multidisciplinary Delphi study. Specialists rated their agreement with a set of 17 statements using a 5-point Likert scale (0 = totally disagree and 4 = totally agree). Consensus on a statement was achieved if the median consensus score (MCS) (expressed as value at which at least 50% of participants agreed) was at least 4 and the interquartile range (IQR) was 3–4. Results: This survey included input from 186 palliative care specialists representing all Italian territory. Consensus was reached on seven statements. More than 70% of participants agreed with the use of low dose of strong opioids in moderate pain treatment and valued transdermal route as an effective option when the oral route is not available. There was strong consensus on the importance of knowing opioid pharmacokinetics for therapy personalization and on identifying immediate-release opioids as key for tailoring therapy to patients’ needs. Limited agreement was reached on items regarding breakthrough pain and the management of opioid-induced bowel dysfunction. Conclusion: These findings may assist clinicians in applying clinical evidence to routine care settings and call for a reappraisal of current pain treatment recommendations with the final aim of optimizing the clinical use of strong opioids in patients with cancer

A novel canine kidney cell line model for the evaluation of neoplastic development: karyotype evolution associated with spontaneous immortalization and tumorigenicity

The molecular mechanisms underlying spontaneous neoplastic transformation in cultured mammalian cells remain poorly understood, confounding recognition of parallels with the biology of naturally occurring cancer. The broad use of tumorigenic canine cell lines as research tools, coupled with the accumulation of cytogenomic data from naturally occurring canine cancers, makes the domestic dog an ideal system in which to investigate these relationships. We developed a canine kidney cell line, CKB1-3T7, which allows prospective examination of the onset of spontaneous immortalization and tumorigenicity. We documented the accumulation of cytogenomic aberrations in CKB1-3T7 over 24 months in continuous culture. The majority of aberrations emerged in parallel with key phenotypic changes in cell morphology, growth kinetics, and tumor incidence and latency. Focal deletion of CDKN2A/B emerged first, preceding the onset and progression of tumorigenic potential, and progressed to a homozygous deletion across the cell population during extended culture. Interestingly, CKB1-3T7 demonstrated a tumorigenic phenotype in vivo prior to exhibiting loss of contact inhibition in vitro. We also performed the first genome-wide characterization of the canine tumorigenic cell line MDCK, which also exhibited CDKN2A/B deletion. MDCK and CKB1-3T7 cells shared several additional aberrations that we have reported previously as being highly recurrent in spontaneous canine cancers, many of which, as with CDKN2A/B deletion, are evolutionarily conserved in their human counterparts. The conservation of these molecular events across multiple species, in vitro and in vivo, despite their contrasting karyotypic architecture, is a powerful indicator of a common mechanism underlying emerging neoplastic activity. Through integrated cytogenomic and phenotypic characterization of serial passages of CKB1-3T7 from initiation to development of a tumorigenic phenotype, we present a robust and readily accessible model (to be made available through the American Type Culture Collection) of spontaneous neoplastic transformation that overcomes many of the limitations of earlier studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10577-015-9474-8) contains supplementary material, which is available to authorized users