[en] A simplified photon time-of-flight (TOF) instrument based on a nanosecond rise-time diode laser at 635 nm was used for the quantification of optical properties of samples. A series of transmittance photon time-of-flight measurements were acquired from absorbing/scattering Intralipid^TM samples of known composition (0<μ_a<0.0014 mm^-1; 13<μ_s<24 mm^-1). Time-of-flight distributions were analyzed using Haar transform with selection of the most parsimonious set of wavelets by genetic algorithm optimization. Results showed that the scattering coefficient could be estimated with a coefficient of variation (CV) of 4.4% and r²=0.95 using wavelets of frequency up to 400 MHz. Absorption coefficients were estimated with a CV of 6.9% and r²=0.99 using steady-state intensity of blank- and scatter-corrected data. Furthermore, it was shown that quantification using simplified electronics can estimate scattering to within 7.2% (r²=0.88) and absorption with an error of 8.3% (r²=0.99). The above findings suggest that a simplified instrument based on a pulsed laser diode and low frequency switches could be developed to quantify absorption in highly scattering media

[en] A sample diagnosis procedure that uses both non-analyte and analyte signals to estimate matrix effects in inductively coupled plasma-mass spectrometry is presented. Non-analyte signals are those of background species in the plasma (e.g. N⁺, ArO⁺), and changes in these signals can indicate changes in plasma conditions. Matrix effects of Al, Ba, Cs, K and Na on 19 non-analyte signals and 15 element signals were monitored. Multiple linear regression was used to build the prediction models, using a genetic algorithm for objective feature selection. Non-analyte elemental signals and non-analyte signals were compared for diagnosing matrix effects, and both were found to be suitable for estimating matrix effects. Individual analyte matrix effect estimation was compared with the overall matrix effect prediction, and models used to diagnose overall matrix effects were more accurate than individual analyte models. In previous work [Spectrochim. Acta Part B 57 (2002) 277], we tested models for analytical decision making. The current models were tested in the same way, and were able to successfully diagnose matrix effects with at least an 80% success rate

[en] Following the recommendations of ICRU Report 90, a re-evaluation has been made of the BIPM standards for air kerma in x-rays and in ⁶⁰Co and ¹³⁷Cs γ-radiations, for absorbed dose to water in ⁶⁰Co γ-radiation and for reference air-kerma rate in ¹⁹²Ir γ-radiation for brachytherapy. The changes arise from three sources: (i) the implementation of new correction factors k_ii and k_W for free-air ionization chambers; (ii) a re-evaluation of the mean excitation energy for graphite and water and the density effect for graphite; (iii) new stated uncertainties for the value of W(air) for dry air and for the related product W(air)s(g,air). Consideration has also been given to new recommendations for photon interaction coefficients, although no corresponding changes have resulted. The heat defect in graphite is also considered. A summary table of the combined effect of these changes is presented. The new standards will be implemented on 1 January 2019. (authors)

[en] The global nuclear industry has a growing volume of nuclear waste which needs to be scanned, sorted according to its activity and material type, then processed into the correct waste packages for long term storage and disposal. It is vital that there is a detailed understanding of the waste inventory stored in long term waste containers, as knowledge of their contents could predict or prevent any adverse effects in storage. The numerous 'scan and sort' tables which are currently used at many different facilities around the world to sort waste into their correct containers are human operated and require very slow gamma scanning procedures combined with educated guesswork to manually sort the waste. This often leads to excessive conservatisms, with placement of lower activity wastes in higher activity containers, which in turn costs significantly more to store. In the United Kingdom it costs UK Pounds 46 k per cubic meter to store intermediate level waste compared to just UK Pound 2.9 k per cubic meter to store low level waste according to a 2008 Department of Energy and Climate Change report in the UK. A proposed solution to this problem, is the use of a robotic manipulator to automatically inspect the 'scan and sort table' in order to produce an accurate 3D model of the table's waste contents and attach an overlaid radiation map. The radiation map contains spectrometry data and can in consequence be used to distinguish and locate specific radioisotopes. The 3D model should be as accurate as possible in order to allow for a second robot arm with an attached gripper to grasp the objects and place them into their designated long-term storage container. Various scanning procedures are explored in this study including basic raster scanning, adaptive raster scanning and point sampling. The optimal solution will in practice be defined by the required application and activity level of the wastes being inspected. The results presented in this study indicate that it is possible to produce a centimeter accurate 3D model of a mixed assortment of components on a nuclear waste 'scan and sort' table. In addition, it was shown that the waste objects emitting radiation could be accurately identified and located, with an overlaid radiation map. This study is applicable across the nuclear waste management sector. Many of the ideas and concepts developed in this study are applicable in other decommissioning settings for example, dismantling of legacy gloveboxes or routine inspection of nuclear waste packages in storage. (authors)

[en] The correction factor for recombination losses k_s has been determined for the BIPM parallel-plate ionization chamber type in the pulsed photon beam of a clinical linear accelerator. Initial recombination is in agreement with that obtained for the same chamber type in a continuous beam, while linearity in the volume recombination loss is confirmed at dose rates up to 80 pC per pulse, which corresponds to about 0.33 mGy per pulse (or around 2 Gy min^-1 at 100 Hz)

[en] Our team at the United States Army Research Laboratory (ARL) has designed and developed a low-power, compact, wireless-networked gamma sensor (WGS) array. The WGS system provides high sensitivity gamma photon detection and remote warning for a broad range of radioactive materials. This sensor identifies the presence of a 1 μCi Cs137 source at a distance of 1.5 m. The networked array of sensors presently operates as a facility and laboratory sensor for the movement of radioactive check sources. Our goal has been to apply this architecture for field security applications by incorporating low-power design with compact packaging. The performance of this radiation measurement network is demonstrated for both detection and location of radioactive material.

[en] Substantial changes in ion chamber perturbation correction factors in ⁶⁰Co γ-rays, suggested by recent Monte Carlo (MC) calculations, would cause a decrease of about 1.5% in the reference dosimetry of all types of charged particles (electrons, protons and heavier ions) based on calculated k_Q values. It has gone largely unnoticed that the ratio of calibration coefficients N_D,w,Co60 and N_K,air,Co60 yields an experimental value of F_ch,Co60 = (s_w-air p_ch)_Co60 through N_D,air,Co60. Coefficients provided by the IAEA and traceable to the BIPM for 91 NE-2571 chambers result in an average F_ch,Co60 which is compared with published (and new) MC simulations and with the value in IAEA TRS-398. It is shown that TRS-398 agrees within 0.12% with the experimental F_ch,Co60. The 1.5% difference resulting from MC calculations (1.1% for the new simulations) cannot be justified using current fundamental data and BIPM standards if consistency in the entire dosimetry chain is sought. For photons, MC k_Q factors are compared with TRS-398. Using the same uncertainty for W_air, the two sets of data overlap considerably. Experimental k_Q values from standards laboratories lie between the two sets of calculated values, showing no preference for one set over the other. Observed chamber-to-chamber differences, that include the effect of waterproof sleeves (also seen for ⁶⁰Co), justify the recommendation in TRS-398 for k_Q values specifically measured for the user chamber. Current developments on I-values for the stopping powers of water and graphite are presented. A weighted average I_water = 78 ± 2 eV is obtained from published experimental and DRF-based values; this would decrease s_w-air for all types of radiotherapy beams between 0.3% and 0.6%, and would consequently decrease the MC derived F_ch,Co60. The implications of a recent proposal for I_graphite = 81 eV are analysed, resulting in a potential decrease of 0.7% in N_K,air,Co60 which would raise the experimental F_ch,Co60; this would result in an increase of about 0.8% in the current TRS-398 value when referred to the BIPM standards. MC derived F_ch,Co60 using new stopping powers would then agree at a level of 0.1% with the experimental value, confirming the need for consistency in the dosimetry chain data. Should world average standards be used as reference, the figures would become +0.4% for TRS-398 and −0.3% for the MC calculation. F_ch,Q calculated for megavoltage photons using new stopping powers would decrease by between 0.2% and 0.5%. When they enter as a ratios in k_Q, differences with MC values based on current key data would be within 0.2% but their discrepancy with k_Q experimental photon values remains unresolved. For protons the new data would require an increase in W_air,Q of about 0.6%, as this is inferred from a combination of calorimetry and ionometry. This consistent scenario would leave unchanged the current TRS-398 k_Q (NE-2571) data for protons, as well as for ions heavier than protons unless new independent W_air,Q values become available. Also in these advanced radiotherapy modalities, the need for maintaining data consistency in an analysis that unavoidably must include the complete dosimetry chain is demonstrated. (paper)

[en] 

Purpose

: HER2 signaling functional activity may be important to measure in addition to HER2 protein quantification when identifying patients eligible for HER2 therapies. A HER2 Signaling Function (CELx HSF) Test for HER2-negative patients uses patient’s live tumor cells on a biosensor to identify patients with abnormally high HER2-related signaling (HSFs+) likely to respond to anti-HER2 therapies.

Methods

: The CELx HSF test was employed to: (1) characterize the sensitivity and specificity of the test to detect abnormal levels of HER2 signaling; (2) evaluate the inhibitory effectiveness of five different anti-HER2 therapies; (3) assess the correlation between CELx HSF test detection of abnormal HER2 signaling and response to HER2 therapy using xenograft models; and (4) confirm the prevalence of abnormal HER2 signaling amongst HER2-negative breast cancer patients (HER2−/HSFs+).

Results

: HER2−/HSFs+ breast cancer patient samples were identified and showed sensitivity to five approved anti-HER2 therapies. Xenograft studies using both HER2+ and HER2− cell lines confirmed that CELx HER2 signaling status better predicts HER2 inhibitor efficacy than HER2 receptor status. In a study of 114 HER2-negative breast tumor patient samples, 27 (23.7%; 95% CI = 17–32%) had abnormal HER2 signaling (HSFs+). A ROC curve constructed with this dataset projects the CELx HSF Test would have greater than 90% sensitivity and specificity to detect the HER2−/HSFs+ patient population.

Conclusions

: The CELx HSF test is a well-characterized functional biomarker assay capable of identifying dynamic HER2-driven signaling dysfunction in tumor cells from HER2-negative breast cancer patients. This test has demonstrated efficacy of various HER2 targeted therapies in live tumor cells from the HSFs+ population and correlated the test result to HER2 drug response in mouse xenograft studies. The proportion of HER2-negative breast cancer patients found to have abnormal HER2 signaling in a 114 patient sample study, 20–25%, is significant. A clinical trial to evaluate the efficacy of anti-HER2 therapies in this patient population is warranted.

[en] PFAS source zone remediation by foam fractionation and in situ-fluidisation. This project aims to develop two methods for the in-situ remediation of per- and poly-fluroalkyl substances (PFAS) contamination, downhole foam fractionation for in-situ groundwater treatment, and in-situ fluidisation for soil treatment, both separately and in combination. Using these methods, PFASs will be removed in the form of a foam, which will be extracted at the surface as a liquid concentrate. These techniques could enable PFAS removal efficiencies of greater than 90%, providing entirely new methods for the aggressive removal of PFAS from contaminated source zones. This project will enable rapid removal of bulk PFAS from soils and groundwater and reduce the potential for further spreading. Note: The Australian Research Council (ARC) awarded AUD $900,000 grant funding for this project. An additional AUD $160,000 contribution from OPEC Systems is provided as part of the grant funding arrangement. Date of funding was 1 July 2019. (author)