Light-by-light scattering in ultraperipheral collisions of heavy ions with future FoCal and ALICE 3 detectors

We discuss possible future studies of photon-photon (light-by-light) scattering using a planned FoCal and ALICE 3 detectors. We include different mechanisms of $\gamma\gamma\to\gamma\gamma$ scattering, such as double-hadronic photon fluctuations, $t/u$-channel neutral pion exchange or resonance excitations ($\gamma \gamma \to R$) and deexcitation ($R \to \gamma \gamma$). The broad range of (pseudo)rapidities and lower cuts on transverse momenta open a necessity to consider not only dominant box contributions but also other subleading contributions. Here we include low mass resonant $R = \pi^0$, $\eta$, $\eta'$ contributions. The resonance contributions give intermediate photon transverse momenta. However, these contributions can be eliminated by imposing windows on di-photon invariant mass. We study and quantify individual box contributions (leptonic, quarkish). The electron/positron boxes dominate at low $M_{\gamma \gamma}<1$ GeV di-photon invariant masses. The PbPb$\to$PbPb$\gamma \gamma$ cross section is calculated within equivalent photon approximation in the impact parameter space. Several differential distributions are presented and discussed. We consider four different kinematic regions. We predict cross section in the (mb-b) range for typical ALICE 3 cuts, a few orders of magnitude larger than for the current ATLAS or CMS experiments. We also consider the two-$\pi^0$ background which can, in principle, be eliminated at the new kinematical range for the ALICE 3 measurements by imposing dedicated cuts on di-photon transverse momentum and\or so-called vector asymmetry.Comment: 20 pages, 19 Figures, 3 Tables; misprint corrected, 1 figure adde

FindFoci: a focus detection algorithm with automated parameter training that closely matches human assignments, reduces human inconsistencies and increases speed of analysis

Accurate and reproducible quantification of the accumulation of proteins into foci in cells is essential for data interpretation and for biological inferences. To improve reproducibility, much emphasis has been placed on the preparation of samples, but less attention has been given to reporting and standardizing the quantification of foci. The current standard to quantitate foci in open-source software is to manually determine a range of parameters based on the outcome of one or a few representative images and then apply the parameter combination to the analysis of a larger dataset. Here, we demonstrate the power and utility of using machine learning to train a new algorithm (FindFoci) to determine optimal parameters. FindFoci closely matches human assignments and allows rapid automated exploration of parameter space. Thus, individuals can train the algorithm to mirror their own assignments and then automate focus counting using the same parameters across a large number of images. Using the training algorithm to match human assignments of foci, we demonstrate that applying an optimal parameter combination from a single image is not broadly applicable to analysis of other images scored by the same experimenter or by other experimenters. Our analysis thus reveals wide variation in human assignment of foci and their quantification. To overcome this, we developed training on multiple images, which reduces the inconsistency of using a single or a few images to set parameters for focus detection. FindFoci is provided as an open-source plugin for ImageJ

Biological in-vivo measurement of dose distribution in patients' lymphocytes by gamma-H2AX immunofluorescence staining: 3D conformal- vs. step-and-shoot IMRT of the prostate gland

<p>Abstract</p> <p>Background</p> <p>Different radiation-techniques in treating local staged prostate cancer differ in their dose- distribution. Physical phantom measurements indicate that for 3D, less healthy tissue is exposed to a relatively higher dose compared to SSIMRT. The purpose is to substantiate a dose distribution in lymphocytes <it>in-vivo </it>and to discuss the possibility of comparing it to the physical model of total body dose distribution.</p> <p>Methods</p> <p>For each technique (3D and SSIMRT), blood was taken from 20 patients before and 10 min after their first fraction of radiotherapy. The isolated leukocytes were fixed 2 hours after radiation. DNA double-strand breaks (DSB) in lymphocytes' nuclei were stained immunocytochemically using the gamma-H2AX protein. Gamma-H2AX foci inside each nucleus were counted in 300 irradiated as well as 50 non-irradiated lymphocytes per patient. In addition, lymphocytes of 5 volunteer subjects were irradiated externally at different doses and processed under same conditions as the patients' lymphocytes in order to generate a calibration-line. This calibration-line assigns dose-value to mean number of gamma-H2AX foci/ nucleus. So the dose distributions in patients' lymphocytes were determined regarding to the gamma-H2AX foci distribution. With this information a cumulative dose-lymphocyte-histogram (DLH) was generated. Visualized distribution of gamma-H2AX foci, correspondingly dose per nucleus, was compared to the technical dose-volume-histogram (DVH), related to the whole body-volume.</p> <p>Results</p> <p>Measured <it>in-vivo </it>(DLH) and according to the physical treatment-planning (DVH), more lymphocytes resulted with low-dose exposure (< 20% of the applied dose) and significantly fewer lymphocytes with middle-dose exposure (30%-60%) during Step-and-Shoot-IMRT, compared to conventional 3D conformal radiotherapy. The high-dose exposure (> 80%) was equal in both radiation techniques. The mean number of gamma-H2AX foci per lymphocyte was 0.49 (3D) and 0.47 (SSIMRT) without significant difference.</p> <p>Conclusions</p> <p><it>In-vivo </it>measurement of the dose distribution within patients' lymphocytes can be performed by detecting gamma-H2AX foci. In case of 3D and SSIMRT, the results of this method correlate with the physical calculated total body dose-distribution, but cannot be interpreted unrestrictedly due to the blood circulation. One possible application of the present method could be in radiation-protection for <it>in-vivo </it>dose estimation after accidental exposure to radiation.</p

ADAM17 Silencing in Mouse Colon Carcinoma Cells: The Effect on Tumoricidal Cytokines and Angiogenesis

ADAM17 (a disintegrin and metalloprotease 17) is a major sheddase for numerous growth factors, cytokines, receptors, and cell adhesion molecules and is often overexpressed in malignant cells. It is generally accepted that ADAM17 promotes tumor development via activating growth factors from the EGF family, thus facilitating autocrine stimulation of tumor cell proliferation and migration. Here we show, using MC38CEA murine colon carcinoma model, that ADAM17 also regulates tumor angiogenesis and cytokine profile. When ADAM17 was silenced in MC38CEA cells, in vivo tumor growth and in vitro cell motility were significantly diminished, but no effect was seen on in vitro cell proliferation. ADAM17-silencing was accompanied by decreased in vitro expression of vascular endothelial growth factor-A and matrix metalloprotease-9, which was consistent with the limited angiogenesis and slower growth seen in ADAM17-silenced tumors. Among the growth factors susceptible to shedding by ADAM17, neuregulin-1 was the only candidate to mediate the effects of ADAM17 on MC38CEA motility and tumor angiogenesis. Concentrations of TNF and IFN gamma, cytokines that synergistically induced proapoptotic effects on MC38CEA cells, were significantly elevated in the lysates of ADAM17-silenced tumors compared to mock transfected controls, suggesting a possible role for ADAM17 in host immune suppression. These results introduce new, complex roles of ADAM17 in tumor progression, including its impact on the anti-tumor immune response

High resolution and contrast 7 tesla MR brain imaging of the neonate

IntroductionUltra-high field MR imaging offers marked gains in signal-to-noise ratio, spatial resolution, and contrast which translate to improved pathological and anatomical sensitivity. These benefits are particularly relevant for the neonatal brain which is rapidly developing and sensitive to injury. However, experience of imaging neonates at 7T has been limited due to regulatory, safety, and practical considerations. We aimed to establish a program for safely acquiring high resolution and contrast brain images from neonates on a 7T system.MethodsImages were acquired from 35 neonates on 44 occasions (median age 39 + 6 postmenstrual weeks, range 33 + 4 to 52 + 6; median body weight 2.93 kg, range 1.57 to 5.3 kg) over a median time of 49 mins 30 s. Peripheral body temperature and physiological measures were recorded throughout scanning. Acquired sequences included T2 weighted (TSE), Actual Flip angle Imaging (AFI), functional MRI (BOLD EPI), susceptibility weighted imaging (SWI), and MR spectroscopy (STEAM).ResultsThere was no significant difference between temperature before and after scanning (p = 0.76) and image quality assessment compared favorably to state-of-the-art 3T acquisitions. Anatomical imaging demonstrated excellent sensitivity to structures which are typically hard to visualize at lower field strengths including the hippocampus, cerebellum, and vasculature. Images were also acquired with contrast mechanisms which are enhanced at ultra-high field including susceptibility weighted imaging, functional MRI, and MR spectroscopy.DiscussionWe demonstrate safety and feasibility of imaging vulnerable neonates at ultra-high field and highlight the untapped potential for providing important new insights into brain development and pathological processes during this critical phase of early life

Application of ALS data in interpretation of past and contemporary land use forms using the example of Grojec hill

Artykuł prezentuje możliwości wykorzystania informacji pochodzących z lotniczego skanowania laserowego LiDAR jako źródła danych w badaniach nad użytkowaniem terenu. Do oceny funkcjonalności użyto chmury punktów powstałej w ramach projektu ISOK. Jako obszar badań wybrano teren wzgórza Grojec, położonego na południu województwa śląskiego, w południowej Polsce. Z pozyskanych chmur punktów wygenerowano modele cieniowane rzeźby i pokrycia terenu. Następnie zostały one zinterpretowane i zwektoryzowane w celu ustalenia maksymalnego zasięgu pól uprawnych i ich obecnego użytkowania. Poza tym oznaczone zostały pojedyncze obiekty antropogeniczne z różnych okresów czasu: średniowieczne stanowisko archeologiczne, kamieniołomy z XIX i XX wieku, stawy hodowlane. Po przeprowadzonej analizie wyników przedstawiono następujące wnioski: 1. Dawne formy agrarnego użytkowania ziemi są w LiDAR wyraźnie i czytelnie widoczne. Interpretacja modelu umożliwia wskazanie nie tylko maksymalnego zasięgu rolnictwa, ale również granic poszczególnych działek. 2. Ślady działalności gospodarczej i kulturowej człowieka charakteryzują się dużymi możliwościami interpretacyjnymi. Wyniki wskazują na wielki potencjał drzemiący w oznaczaniu i wstępnej parametryzacji stanowisk historycznych i archeologicznych z użyciem teledetekcyjnej prospekcji ALS. Interpretacja LiDAR nie umożliwia określenia czasowego momentu wykorzystywania poszczególnych obiektów. Tym niemniej wszelkie trudności z ustaleniem wieku powinny być weryfikowane i porównywane z innymi źródłami informacji przestrzennej, co podniesie wartość naukową badania.The article presents possible use of airborne laser scanning (ALS/LiDAR) data as an information source in researches of land use. Point clouds generated within the ISOK Project (The state information system of natural hazards prevention) were used to evaluate the functional usefulness. The Grojec hill located in the southern part of the Silesian voivodeship (south of Poland) was chosen as the research area. Shaded models of the terrain relief and land cover were generated from point clouds. Afterwards they were interpreted and vectorized in order to determine the maximum range of arable lands and their current use. Apart from that single man-made objects from different periods of time were marked; they included a medieval archaeological excavation, quarries from XIX/XX century and ponds. Conclusions from the analyses: 1. The former forms of agricultural land use are clearly visible in LiDAR data. Interpretation of a model is useful for determination of the maximum range of arable lands, as well as borders of individual fields. 2. Also the marks of human cultural and economic activity are clearly visible and may be of high interest for interpreters. Applications of ALS data with remote sensing prospection are characterised by the high potential in initial researches of archaeological and historical excavations. Interpretation of LiDAR data cannot be used for determination of time when particular objects were used. However, as a general rule, the difficulties in setting the age should be verified and compared with other spatial data sources, what would increase the research value of performed works

Settlement Sites in the Nile Delta

The 4th millennium and the beginning of the 3rd millennium B. C. is a time of significant transformations in the Nile Delta. In the beginning of that period, possibly for the first time, the whole Nile Delta was settled by groups of people of the Lower Egyptian Culture. Another change is connected with the appearance of Naqadians in the north, which influenced local societies of the Lower Egyptian culture. As a result, a new unit that integrated elements of both cultural complexes arose. The process of state formation, leading to the foundation of a unified Egyptian state under the reign of king Narmer is the last important political, social and economic change of the Nile Delta in this period. These three changes have been recognised on almost all Delta settlement sites known today and are well represented among pottery, flint assemblages and in the architecture of the sites. In this paper we have tried to compare published materials from several Nile Delta site dated to the 4th millennium and the beginning of the 3rd millennium B. C. to show how these three transformations are visible in archaeological records.Le 4e millénaire et le début du 3e millénaire correspondent à une période de transformations importantes dans le delta du Nil. C’est durant cette époque que la région est entièrement habitée, sans doute pour la première fois, par des groupes rattachés aux cultures de Basse Égypte. Une autre transformation est liée à l’apparition de traditions nagadiennes dans le nord du pays, qui ont définitivement influencé les sociétés autochtones, aboutissant au développement d’un nouveau complexe culturel intégrant les composantes des deux entités. Le processus de formation étatique, qui conduit à la fondation d’un État unifié sous le règne du roi Narmer, est la dernière mais la plus importante des mutations politiques, sociales et économiques qui marquent le Delta durant cette période. Ces transformations sont connues sur la plupart des sites d’habitat de la région découverts jusqu’à présent et sont bien attestées dans le matériel céramique et lithique mais aussi dans l’architecture des localités étudiées. Dans cet article nous comparons les données publiées pour la plupart des sites du 4e et du début du 3e millénaire afin de mettre en évidence ces trois phases de changements bien visibles dans les données archéologiques.Jucha Mariusz A., Mączyńska Agnieszka. Settlement Sites in the Nile Delta. In: Archéo-Nil. Revue de la société pour l'étude des cultures prépharaoniques de la vallée du Nil, n°21, 2011. La chronologie relative de la Basse Vallée du Nil jusqu’au 3e millénaire BC (coord. E.C. Köhler) pp. 33-50