Monte Carlo flattening filter design to high energy intraoperative electron beam homogenization

[EN] Intraoperative radiotherapy using mobile linear accelerators is used for a wide variety of malignancies. However, when large fields are used in combination with high energies, a deterioration of the flatness dose profile is measured with respect to smaller fields and lower energies. Indeed, for the LIAC HWL of Sordina, this deterioration is observed for the 12 MeV beam combined with 10 cm (or larger) diameter applicator. Aimed to solve this problem, a flattening filter has been designed and validated evaluating the feasibility of its usage at the upper part of the applicator. The design of the filter was based on Monte Carlo simulations because of its accuracy in modeling components of clinical devices, among other purposes. The LIAC 10 cm diameter applicator was modeled and simulated independently by two different research groups using two different MC codes, reproducing the heterogeneity of the 12 MeV energy beam. Then, an iterative process of filter design was carried out. Finally, the MC designed conical filter with the optimal size and height to obtain the desired flattened beam was built in-house using a 3D printer. During the experimental validation of the applicator-filter, percentage depth dose, beam profiles, absolute and peripheral dose measurements were performed to demonstrate the effectiveness of the filter addition in the applicator. These measurements conclude that the beam has been flattened, from 5.9% with the standard configuration to 1.6% for the configuration with the filter, without significant increase of the peripheral dose. Consequently, the new filter-applicator LIAC configuration can be used also in a conventional surgery room. A reduction of 16% of the output dose and a reduction of 1.1 mm in the D50 of the percentage depth dose was measured with respect to the original configuration. This work is a proof-of-concept that demonstrates that it is possible to add a filter able to flatten the beam delivered by the Sordina LIAC HWL. Future studies will focus on more refined technical solutions fully compatible with the integrity of the applicator, including its sterilization, to be safely introduced in the clinical practice.The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Giuseppe Felici reports a relationship with S.I.T. Sordina IORT Technologies S.p.A. that includes: employment. We thank the professionals and facilities at the 3D printing and metrology department in the Mechanics Unit at IFIC. JV thanks I. Diaz for measuring the PLA density. We thank S.I.T. SORDINA IORT Tech-nologies SpA for providing the applicator used for testing the filter during the measurements. JV, FB, and JP would like to acknowledge the Spanish "Ministerio de Ciencia e Innovacion" (MCIN) grant PID2021-125096NB-I00 funded by MCIN/AEI/10.13039 and the "Generalitat Valenciana" (GVA) grant PROMETEO/2021/064.Oliver-Gil, S.; Vijande, J.; Tejedor-Aguilar, N.; Miró Herrero, R.; Rovira-Escutia, JJ.; Ballester, F.; Juste-Vidal, B.... (2023). Monte Carlo flattening filter design to high energy intraoperative electron beam homogenization. Radiation Physics and Chemistry. 212. https://doi.org/10.1016/j.radphyschem.2023.11110221

Abundance and distribution of sperm whales in the Canary Islands : can sperm whales in the Archipelago sustain the current level of ship-strike mortalities?

Funding was provided through an agreement between the Canary Islands Government and the Spanish Ministries of the Environment and Defence. Additional survey effort on the Amanay, Banquete and Concepción seamounts was funded by the Fundación Biodiversidad-MAGRAMA via the LIFE-INDEMARES project.Sperm whales are present in the Canary Islands year-round, suggesting that the archipelago is an important area for this species in the North Atlantic. However, the area experiences one of the highest reported rates of sperm whale ship-strike in the world. Here we investigate if the number of sperm whales found in the archipelago can sustain the current rate of ship-strike mortality. The results of this study may also have implications for offshore areas where concentrations of sperm whales may coincide with high densities of ship traffic, but where ship-strikes may be undocumented. The absolute abundance of sperm whales in an area of 52933 km2, covering the territorial waters of the Canary Islands, was estimated from 2668 km of acoustic line-transect survey using Distance sampling analysis. Data on sperm whale diving and acoustic behaviour, obtained from bio-logging, were used to calculate g(0) = 0.92, this is less than one because of occasional extended periods when whales do not echolocate. This resulted in an absolute abundance estimate of 224 sperm whales (95% log-normal CI 120-418) within the survey area. The recruitment capability of this number of whales, some 2.5 whales per year, is likely to be exceeded by the current ship-strike mortality rate. Furthermore, we found areas of higher whale density within the archipelago, many coincident with those previously described, suggesting that these are important habitats for females and immature animals inhabiting the archipelago. Some of these areas are crossed by active shipping lanes increasing the risk of ship-strikes. Given the philopatry in female sperm whales, replacement of impacted whales might be limited. Therefore, the application of mitigation measures to reduce the ship-strike mortality rate seems essential for the conservation of sperm whales in the Canary Islands.Publisher PDFPeer reviewe

Phosphorylation by Dyrk1A of Clathrin Coated Vesicle-Associated Proteins: Identification of the Substrate Proteins and the Effects of Phosphorylation

Dyrk1A phosphorylated multiple proteins in the clathrin-coated vesicle (CCV) preparations obtained from rat brains. Mass spectrometric analysis identified MAP1A, MAP2, AP180, and α- and β-adaptins as the phosphorylated proteins in the CCVs. Each protein was subsequently confirmed by [32P]-labeling and immunological methods. The Dyrk1A-mediated phosphorylation released the majority of MAP1A and MAP2 and enhanced the release of AP180 and adaptin subunits from the CCVs. Furthermore, Dyrk1A displaced adaptor proteins physically from CCVs in a kinase-concentration dependent manner. The clathrin heavy chain release rate, in contrast, was not affected by Dyrk1A. Surprisingly, the Dyrk1A-mediated phosphorylation of α- and β-adaptins led to dissociation of the AP2 complex, and released only β-adaptin from the CCVs. AP180 was phosphorylated by Dyrk1A also in the membrane-free fractions, but α- and β-adaptins were not. Dyrk1A was detected in the isolated CCVs and was co-localized with clathrin in neurons from mouse brain sections and from primary cultured rat hippocampus. Previously, we proposed that Dyrk1A inhibits the onset of clathrin-mediated endocytosis in neurons by phosphorylating dynamin 1, amphiphysin 1, and synaptojanin 1. Current results suggest that besides the inhibition, Dyrk1A promotes the uncoating process of endocytosed CCVs

Observations of the Crab Nebula and Pulsar with the Large-Sized Telescope Prototype of the Cherenkov Telescope Array

CTA (Cherenkov Telescope Array) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies. The Large-Sized Telescope prototype (\LST{}) is located at the Northern site of CTA, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to $\simeq 20$ GeV. \LST{} started performing astronomical observations in November 2019, during its commissioning phase, and it has been taking data since then. We present the first \LST{} observations of the Crab Nebula, the standard candle of very-high energy gamma-ray astronomy, and use them, together with simulations, to assess the basic performance parameters of the telescope. The data sample consists of around 36 hours of observations at low zenith angles collected between November 2020 and March 2022. \LST{} has reached the expected performance during its commissioning period - only a minor adjustment of the preexisting simulations was needed to match the telescope behavior. The energy threshold at trigger level is estimated to be around 20 GeV, rising to $\simeq 30$ GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.12 to 0.40 degrees, and energy resolution from 15 to 50\%. Flux sensitivity is around 1.1\% of the Crab Nebula flux above 250 GeV for a 50-h observation (12\% for 30 minutes). The spectral energy distribution (in the 0.03 - 30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula.Comment: Submitted to Ap

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Advances in research on the impacts of anti-submarine sonar on beaked whales

Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, inNon the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to individual outcomes. Spatial management specific to BW habitat, such as the MFAS ban in the Canary Islands, has proven to be an effective mitigation tool and mitigation measures should be established in other areas taking into consideration known population-level information.</p

Anales de Edafología y Agrobiología Tomo 38 Número 7-8

Suelos Características generales de los suelos fersialíticos de las Islas Canarias, por A. Rodríguez R., M. L. Tejedor S. y E. Fernández.-. Estudio del cambisol Los Labradossobre granito de El Pellroso (Sevilla). II. Mineralogía de las arenas y micromorfología, por L. Corral M., N. Bellinfante C., M. Medina C. y G. Paneque G.-- Nuevos datos sobre la influencia de la vegetación en la formación del suelo en Galicia. I. Interceptación de la precipitación, por R. Mª Calvo de Anta, A. Paz G. y F. Días-Fierros V.-- Las clases y subclases de capacidad de uso de los suelos de Gran Canaria, por J. Sánchez D., A. Guerra D. y E. Fernández C.-- Retención de 1, 3, 5, triazina-2, 4, diamino-6, cloro-N, N', dietilo (Simazina) sobre muestras homoiónicas de montmorillonita y vermiculita y sobre un gel de sílice, por J. de D. López G., C. Valenzuela C. y M. Gaitán P.-- Fósforo orgánico en andosoles y su relación con otros parámetros del suelo, por J. A. Pérez M., F. Gutiérrez J., E. Fernández C. e l. Trujillo J. del Castillo.--Fraccionamiento de los fosfatos orgánicos en andosoles de las Islas Canarias, por F. Gutiérrez J., J. A. Pérez M., E. Fernández C. e l. Trujillo J. del Castillo.-- Fraccionamiento de los fosfatos inorgánicos en anllosoles de las Islas Canarias, por J. A. Pérez M., F. Gutierrez J., F. Fernández C. y A. Borges P.-- Studies on sodium-calcium exchange equilibria. I. In danish soils. l. The Equilibrium activity ratios and the Quantity/Intensity relationships of sodium in marsh soils, by M. H. Nafady.-- Studies on sodium-calcium exchange equilibria. I. In danish soils. 2. The form of sodium exchange isotherm, its properties, and the effect of sorne treatments, by M. H. Nafady.-- El color en los suelos y su posible influencia en la fertilidad del olivo, por C. Siwa, J. Campos, J. Aguilar y M. Delgado.-- Fertilidad de los suelos. Efecto de la adición de caliza sobre el pH y la disponibilidad de elementos de un suelo ácido con especial referencia al fósforo, por E. Vieitez, J. Arines y R. Fábregas. Extracción de hierro activo en suelos calizos con pirofosfato, por M. R. Martínez F., F. G. Fernández, M. Romero y .M. Caro.--Metabolismo fosfórico de Aspergil/us niger en suelos calizos y salinos, por A. Ortuño, Jª Noguera, A. Hernansáez y Tª Armero.-- Acción solubilizadora de fósforo por Aspergillus niger y Pseudomonas fluorescens, por A. Ortuño, A. Hernansáez. J.Noguera, V. Morales y T. Armero.-- Rhizobium meliloti nativo en suelos cultivados con cereales, por M. A. Sagardoy.-- Nitrógeno, fósforo, potasio y elementos menores en los suelos volcánicos del valle de Sibundoy, Colombia, por O. Bastidas, A. Caicedo, F. Romo, M. Villota, M. Blasco y L. Legarda.-- Extracción con ditionito y oxalato de óxidos de hierro libre en suelos calizos y su relación con el extraído con pirofosfato, por M. R. Martínez F., M. Romero, F. G. Fernández y M. Caro.-- Degradación de simazina y atrazina en suelos salinos del Sureste español por A. Ortulio, M. Parra y J. Egea C.-- Isotermas de adsorción de DBCP en suelos, por O. Carpena A., A. Ortuño M., J. M. Abrísqueta G., J. Laencina S. y A. Alonso-Allende Y.--Estudio de la persistencia del nematicida 1,2-dibromo-3-cloropropano (DBCP) y su efectividad sobre Tylenchulus semipenetrans en un suelo citrícola de la vega del Segura, por A. Ortuíio, J. M. Abrisqueta v J. Gómez.-- Contribución al control fitosanitario del Acaro de las Maravillas de los Agrios (Acería sheldoni Ewing), por J. Gómez. A. Ortuño y F. L. Cánovas.-- Estudio de la contaminación de suelos y plantas por metales pesados en los entornos de las autopistas que confluven en Madrid. I. Autopistas de Barajas y Valencia, por J. R. Sanchidrián y M. Mariño.—Nutrición y Fisiología Vegetal.-- Acción del ácido cx-naftalén acético sobre los procesos de histogénesis de tejidos de Heliantltus tuberosus L. yariedad Blanc Sutton cultivados in vitro. I. Neoformación de raíces y organización de zonas generatrices libero-leñosas, por M. J. García R.-- Estudio de las variaciones en el crecimiento de la raíz de guisante nroducidas por tres ácidos húmicos, por C. Ortega, C. Fortún, A. Polo y E. Dorado.-- Variaciones ultraestructurales en Parmelia conspersa S. L. provocadas in vitro por diferentes grados de humedad ambiental , por C. Ascaso.-- Nota previa. Modelación matemática y evaluación agrícola de suelos, por D. de la Rosa y J. Almorza.—Estudios recapitulativos. El Pinus radiata D. Don en Chile. Revisión de las condiciones del cultivo, por C. González 0., R. Kosche P. y M. Lachica. NotasPeer reviewe