148. Changes in lateral dimensions of irradiated volume and their impact on the accuracy of dose delivery during radiotherapy for head and neck cancer

AimTo assess changes in lateral dimensions of irradiated volume during head and neck cancer radiotherapy and their impact on dose delivery accuracy.Material and methodsLateral dimensions of irradiated volumes were measured in 5 predefined points using computed tomography, simulator and manually with calipers, prior to treatment and then bi-weekly. For each measurement reference point dose was calculated and verified using in vivo dosimetry. Early radiation reactions, patient's weight changes and the need to modify radiotherapy accessories were also assessed. All these parameters were analyzed in relation to tumor site and stage, treatment field size, radiation dose and the degree of radiation reactions.ResultsThe study included 33 head and neck cancer patients (24 men and 9 women) aged 24–77 (median 56). All patients were irradiated using the parallel opposed megavoltage fields ranging from 49 to 180 cm2 (median 121 cm2) to the dose of 44 to 80 Gy (median 66 Gy). Radiation reactions included mucositis (grade 3 – 1 patient, grade 2 – 17 patients, grade 1 – 13 patients) and dysphagia (grade 2 – 12 patients, grade 1 – 16 patients). The body mass changes during radiotherapy ranged from −18 to +4 kg (median −5 kg). In 1 patient radiotherapy accessories had to be modified three times during the treatment, in 6 – twice and in 10 – once. Lateral dimensions changes >5 mm occurred in all but one patient (range −37 to +16 mm). Theoretical doses calculated for changed dimensions varied from prescribed by −2.5% to +6% (median +2%). Differences larger than 5% were present in 4.8% of calculations. In vivo dose measurements (after introduction of necessary corrections) demonstrated difference from prescribed dose larger than 5% in 7.6% of measurements.ConclusionChanges in the lateral dimensions of irradiated volume during head and neck cancer radiotherapy may lead to some inaccuracies in delivered doses. Such situations may necessitate adequate corrections of dose calculations and modification of radiotherapy accessories during the course of treatment

Survivin antiapoptotic gene expression as a prognostic factor in non-small cell lung cancer: in situ hybridization study.

Survivin is an inhibitor of apoptosis that plays a significant role in cell cycle regulation and is important for survival prognosis in many neoplasms. Survivin expression was assessed by in situ hybridization (ISH) in 60 consecutive patients (54 males and 4 females) with NSCLC treated between 1993 and 1997. The examined patients had IIB and IIIA stage according to TNM system. In all cases the chemotherapy with cisplatin and etoposide (2 cycles) was administered prior the surgery; in patients responding to the therapy one more cycle was applied. Survivin gene overexpression was observed in 35 patients (58.3%). There was no correlation between survivin mRNA level and histological type of tumor, stage of cell differentiation, stage of disease according to TNM classification, performance status according to WHO and number of chemotherapy regimens administered (p > 0.05). However, the correlation between survivin gene expression and response to the chemotherapy was statistically significant (p = 0.04). Statistical analysis showed that median survival in patients with survivin gene overexpression was shorter (14.0 months) as compared to patients with no expression (60.0 months; p = 0.00002). In survival assessment by means of Kaplan-Meier test, 14.3% of five-year survival was achieved in the former group versus 60% in the latter (p = 0.00003). Univariate analysis (log-rank test) showed that significant independent prognostic factors in NSCLC included: stage of the disease according to TNM classification (p = 0.006), response to chemotherapy (p = 0.005) and pattern of survivin gene expression (p = 0.00003). Multivariate analysis utilizing Cox's model showed that for survival assessment the stage according to TNM, response to the chemotherapy and survivin expression estimated by means of ISH are of statistical significance (p=0.00001). The calculated predictive values showed that ISH technique was quite accurate in assessment of five-year survival. Our data show that survivin expression may be used as a prognostic factor and a target for therapy

Local structure and conductivity behaviour in Bi7WO13.5

Total neutron scattering analysis reveals details of cation coordination and vacancy distribution in Bi7WO13.5.</p

The double rare-earth substituted bismuth oxide system Bi3Y1-xYbxO6

National Science Centre Poland for project grant number 2012/05/E/ST3/02767 and the National Centre for Research and Development Poland for project grant number DKO/PL-TW1/6/2013

A versatile panel of reference gene assays for the measurement of chicken mRNA by quantitative PCR

Quantitative real-time PCR assays are widely used for the quantification of mRNA within avian experimental samples. Multiple stably-expressed reference genes, selected for the lowest variation in representative samples, can be used to control random technical variation. Reference gene assays must be reliable, have high amplification specificity and efficiency, and not produce signals from contaminating DNA. Whilst recent research papers identify specific genes that are stable in particular tissues and experimental treatments, here we describe a panel of ten avian gene primer and probe sets that can be used to identify suitable reference genes in many experimental contexts. The panel was tested with TaqMan and SYBR Green systems in two experimental scenarios: a tissue collection and virus infection of cultured fibroblasts. GeNorm and NormFinder algorithms were able to select appropriate reference gene sets in each case. We show the effects of using the selected genes on the detection of statistically significant differences in expression. The results are compared with those obtained using 28s ribosomal RNA, the present most widely accepted reference gene in chicken work, identifying circumstances where its use might provide misleading results. Methods for eliminating DNA contamination of RNA reduced, but did not completely remove, detectable DNA. We therefore attached special importance to testing each qPCR assay for absence of signal using DNA template. The assays and analyses developed here provide a useful resource for selecting reference genes for investigations of avian biology

The Large Array Survey Telescope -- System Overview and Performances

The Large Array Survey Telescope (LAST) is a wide-field visible-light telescope array designed to explore the variable and transient sky with a high cadence. LAST will be composed of 48, 28-cm f/2.2 telescopes (32 already installed) equipped with full-frame backside-illuminated cooled CMOS detectors. Each telescope provides a field of view (FoV) of 7.4 deg^2 with 1.25 arcsec/pix, while the system FoV is 355 deg^2 in 2.9 Gpix. The total collecting area of LAST, with 48 telescopes, is equivalent to a 1.9-m telescope. The cost-effectiveness of the system (i.e., probed volume of space per unit time per unit cost) is about an order of magnitude higher than most existing and under-construction sky surveys. The telescopes are mounted on 12 separate mounts, each carrying four telescopes. This provides significant flexibility in operating the system. The first LAST system is under construction in the Israeli Negev Desert, with 32 telescopes already deployed. We present the system overview and performances based on the system commissioning data. The Bp 5-sigma limiting magnitude of a single 28-cm telescope is about 19.6 (21.0), in 20 s (20x20 s). Astrometric two-axes precision (rms) at the bright-end is about 60 (30)\,mas in 20\,s (20x20 s), while absolute photometric calibration, relative to GAIA, provides ~10 millimag accuracy. Relative photometric precision, in a single 20 s (320 s) image, at the bright-end measured over a time scale of about 60 min is about 3 (1) millimag. We discuss the system science goals, data pipelines, and the observatory control system in companion publications.Comment: Submitted to PASP, 15p

New trends in the economic systems management in the context of modern global challenges

New trends in the economic systems management in the context of modern global challenges: collective monograph / scientific edited by M. Bezpartochnyi, in 2 Vol. // VUZF University of Finance, Business and Entrepreneurship. – Sofia: VUZF Publishing House “St. Grigorii Bogoslov”, 2020. – Vol. 1. – 309 p

COMAP Early Science: VII. Prospects for CO Intensity Mapping at Reionization

We introduce COMAP-EoR, the next generation of the Carbon Monoxide Mapping Array Project aimed at extending CO intensity mapping to the Epoch of Reionization. COMAP-EoR supplements the existing 30 GHz COMAP Pathfinder with two additional 30 GHz instruments and a new 16 GHz receiver. This combination of frequencies will be able to simultaneously map CO(1--0) and CO(2--1) at reionization redshifts ($z\sim5-8$) in addition to providing a significant boost to the $z\sim3$ sensitivity of the Pathfinder. We examine a set of existing models of the EoR CO signal, and find power spectra spanning several orders of magnitude, highlighting our extreme ignorance about this period of cosmic history and the value of the COMAP-EoR measurement. We carry out the most detailed forecast to date of an intensity mapping cross-correlation, and find that five out of the six models we consider yield signal to noise ratios (S/N) $\gtrsim20$ for COMAP-EoR, with the brightest reaching a S/N above 400. We show that, for these models, COMAP-EoR can make a detailed measurement of the cosmic molecular gas history from $z\sim2-8$, as well as probe the population of faint, star-forming galaxies predicted by these models to be undetectable by traditional surveys. We show that, for the single model that does not predict numerous faint emitters, a COMAP-EoR-type measurement is required to rule out their existence. We briefly explore prospects for a third-generation Expanded Reionization Array (COMAP-ERA) capable of detecting the faintest models and characterizing the brightest signals in extreme detail.Comment: Paper 7 of 7 in series. 19 pages, 10 figures, to be submitted to Ap

COMAP Early Science: III. CO Data Processing

We describe the first season COMAP analysis pipeline that converts raw detector readouts to calibrated sky maps. This pipeline implements four main steps: gain calibration, filtering, data selection, and map-making. Absolute gain calibration relies on a combination of instrumental and astrophysical sources, while relative gain calibration exploits real-time total-power variations. High efficiency filtering is achieved through spectroscopic common-mode rejection within and across receivers, resulting in nearly uncorrelated white noise within single-frequency channels. Consequently, near-optimal but biased maps are produced by binning the filtered time stream into pixelized maps; the corresponding signal bias transfer function is estimated through simulations. Data selection is performed automatically through a series of goodness-of-fit statistics, including $\chi^2$ and multi-scale correlation tests. Applying this pipeline to the first-season COMAP data, we produce a dataset with very low levels of correlated noise. We find that one of our two scanning strategies (the Lissajous type) is sensitive to residual instrumental systematics. As a result, we no longer use this type of scan and exclude data taken this way from our Season 1 power spectrum estimates. We perform a careful analysis of our data processing and observing efficiencies and take account of planned improvements to estimate our future performance. Power spectrum results derived from the first-season COMAP maps are presented and discussed in companion papers.Comment: Paper 3 of 7 in series. 26 pages, 23 figures, submitted to Ap