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A Practical Method to Evaluate and Verify Dose Calculation Algorithms in the Treatment Planning System of Radiation Therapy

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2013年第3期2卷 76-87页

作者： Lanchun Lu Guy Yembi-Goma Jian Z. Wang Nilendu Gupta Zhibin Huang Simon S. Lo douglas martin Nina Mayr Department of Radiation Oncology Case Western Reserve University Cleveland USA Department of Radiation Oncology East Carolina University Greenville USA Department of Radiation Oncology Ohio State University Columbus USA

Purpose: To introduce a practical method of using an Electron Density Phantom (EDP) to evaluate different dose calculation algorithms for photon beams in a treatment planning system (TPS) and to commission the Anisotropic Analytical Algorithm (AAA) with inhomogeneity correction in Varian Eclipse TPS. Methods and Materials: The same EDP with various tissue-equivalent plugs (water, lung exhale, lung inhale, liver, breast, muscle, adipose, dense bone, trabecular bone) used to calibrate the computed tomography (CT) simulator was adopted to evaluate different dose calculation algorithms in a TPS by measuring the actual dose delivered to the EDP. The treatment plans with a 6-Megavolt (MV) single field of 20 × 20, 10 × 10, and 4 × 4 cm2 field sizes were created based on the CT images of the EDP. A dose of 200 cGy was prescribed to the exhale-lung insert. Dose calculations were performed with AAA with inhomogeneity correction, Pencil Beam Convolution (PBC), and AAA without inhomogeneity correction. The plans were delivered and the actual doses were measured using radiation dosimetry devices MapCheck, EDR2-film, and ionization chamber respectively. Measured doses were compared with the calculated doses from the treatment plans. Results: The calculated dose using the AAA with inhomogeneity correction was most consistent with the measured dose. The dose discrepancy for all types of tissues covered by beam fields is at the level of 2%. The effect of AAA inhomogeneity correction for lung tissues is over 14%. Conclusions: The use of EDP and Map Check to evaluate and commission the dose calculation algorithms in a TPS is practical. In Varian Eclipse TPS, the AAA with inhomogeneity correction should be used for treatment planning especially when lung tissues are involved in a small radiation field.

关键词： Electron Density Phantom Treatment Planning System Anisotropic Analytical Algorithm Pencil Beam Convolution Inhomogeneity Correction

A Clinical Dosimetry Analysis of Total Body Irradiation for Leukemia Patients

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2014年第1期3卷 31-42页

作者： Lanchun Lu Jonathan Filippi Akshi Patel Nilendu Gupta Michael Weldon Jeffery Woollard Ahmet Ayan Yi Rong douglas martin Christopher Pelloski Meng Xu Welliver Department of Radiation Oncology The Ohio State University Columbus USA

Background and Purpose: To perform a retrospective in vivo dosimetry study of 129 total body irradiation (TBI) on leukemia and bone marrow transplant patients treated in our clinic from 2008 to 2011 and to find out if there is any indication of the necessity of developing a new efficient TBI approach. Materials and Methods: The in vivo dosimetry data of 129 patients treated with TBI between 2008 and 2011 were retrieved from the database and analyzed. These patients were mostly treated with the regime of a single fraction or 6 fractions with some exceptions of 8-fraction or 2-fraction treatments depending on the protocols that were applied. For every fraction of treatment, 10 pairs of diode dosimeters were used to monitor the doses to the midline of head, neck, arms, mediastinum, left lung, right lung, umbilicus, thigh, knee, and ankle for both AP and PA fields. The doses to the midline of the above body parts were considered to be the average of the AP and PA readings of each diode pair. Dose deviation from the prescribed value for each body part was studied by plotting the histogram of the frequency versus deviation and comparing this with the dose delivered to the midline of the umbilicus to where the dose was prescribed. The correlation of dose deviation to body part thickness was also studied. By studying the dose deviations, we can find the uniformity of general dose distributions for conventional TBI treatments. Results: The retrospective dosimetry study of the 129 TBI patient treatments indicates that for most of the patients treated in our clinic, the doses received by different body parts monitored with in vivo dosimetry were within the window of 10% difference from the prescribed dose. The inhomogeneity of dose on different body parts could be manually improved by using compensators, but the method is cumbersome and time consuming. The dose deviation in many histograms ranging from about ?10% to 10% indicates some incongruity of dose distribution. This cou

关键词： Total Body Irradiation (TBI) In Vivo Dosimetry Lung Block Compensators Patient Setup Treatment Planning

A Many Worlds Interpretation of the Dark Universe

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Journal of High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 828-835页

作者： Richard douglas Bateson Cavendish Laboratory Cambridge UK

In this paper, we discuss a Many Worlds Interpretation (MWI) of Dark Energy and Dark Matter. The universe is viewed cosmologically as a fermionic fluid with a hydrostatic pressure from “Zitterbewegung”, the quantum “zig-zagging” of Dirac particles. At each point in space-time, the pressure from all possible velocity states existing in the Many Worlds sums to provide a dark energy. This provides a ratio of matter energy to pressure energy close to that observed experimentally. Visible matter is the matter observed or measured in a particular velocity state and dark matter is then considered as the unobserved fermion contributions from different orthogonal spatial directions.

关键词： Dark Energy Dark Matter Many Worlds

Increasing dietary fiber intake for type 2 diabetes mellitus management: A systematic review

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World Journal of Diabetes 2024年第5期15卷 1001-1010页

作者： douglas Nitzke Juliana Czermainski Carolina Rosa Chaline Coghetto Sabrina Alves Fernandes Randhall B Carteri Department of Nutrition Centro Universitário CESUCACachoeirinha 94935-630Brazil Department of Hepatology Universidade Federal de Ciências da Saúde de Porto AlegrePorto Alegre 90430-080Brazil Postgraduate Program in Hepatology Universidade Federal de Ciências da Saúde de Porto AlegrePorto Alegre 90050-170Brazil Postgraduate Program in Hepatology Federal University of Health Sciences of Porto Alegre(UFCSPA)Porto Alegre 90050-170Brazil

BACKGROUND Type 2 diabetes is a chronic,non-communicable disease with a substantial global impact,affecting a significant number of *** etiology is closely tied to imbalanced dietary practices and sedentary ***,increasing die-tary fiber(DF)intake has consistently demonstrated health benefits in numerous studies,including improvements in glycemic control and weight *** To investigate the efficacy of DF interventions in the management of type 2 diabetes mellitus(T2DM).METHODS A systematic literature review was conducted to explore the association between DF intake and the management of *** the inclusion and exclusion criteria,a total of 26 studies were included in this *** The main strategies implied to increased DF intake were:High DF diet plus acarbose(2 studies);DF supplements(14 studies);and high DF diets(10 studies).Overall,most studies indicated that increased DF intake resulted in im-provements in glycemic control and weight management in T2DM *** DF represents a valuable strategy in the treatment of type 2 diabetes,improving health *** intake offers the potential to improve quality of life and reduce complications and mortality associated with ***,through supplements or enriched foods,DF contributes significantly to the control of several markers such as HbA1c,blood glucose,triglycerides,low-density lipoprotein,and body weight.

关键词： Type 2 diabetes mellitus Soluble fibers Insoluble fibers Probiotics Blood glucose Nutrition

Assessment of the piroxicam-incited model of synchronized colitis in T-cell receptor alpha chain-deficient mice

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Animal Models and Experimental Medicine 2024年第4期7卷 533-543页

作者： Maximo E.Lange Danisa M.Bescucci Valerie F.Boras Tony Montina G.douglas Inglis douglas inglis 11 lethbridge research and development centre agriculture and agri-food canadalethbridgealbertacanada alberta health services chinook regional hospitallethbridgealbertacanada department of chemistry and biochemistry university of lethbridgelethbridgealbertacanada southern alberta genome sciences centre university of lethbridgelethbridgealbertacanada

Background:A multitude of mouse models are utilized to emulate and study intestinal inflammation.T-cell receptor alpha chain(TCRα)-deficient mice are used as a model of spontaneous colitis that has similarities with human ulcerative ***,colitis is triggered late in the life of the mouse(age:4-5 months),and inflammation does not develop at the same time in different mice.A previously conducted study reported that the administration of the drug piroxicam triggered predictable and early colitis in TCRα-deficient mice at the age of 6-8 ***,a detailed characterization of ensuing inflammation was not ***:We conducted an in-depth examination of piroxicam-triggered colitis in TCRα-deficient mice,with emphasis on spatial histopathologic changes and analysis of expression of inflammatory ***,we tested amelioration of colitis with ***:We confirmed that piroxicam induced a time-prescribed colitis and did so in the proximal colon as well as the cecum of TCRα-deficient *** adminis-tration was observed to induce epithelial hyperplasia,goblet cell loss,and leukocyte infiltration with occasional ulceration.A Swiss roll technique was used to examine the colon and cecum in its ***,we observed that inflammation was mul-tifocal segmental,with areas of tissue damage in between healthy *** addition,we observed variability in the severity of inflammation among replicate animals and treatments,and that the administration of dexamethasone only partially ameliorated inflammation in the proximal ***:Piroxicam consistently induced multifocal segmental colitis in the proxi-mal colon and cecum,although the degree of inflammation was reduced in the ***,spatial variability in inflammation in the large intestine and the inter-replicate variation in the severity of inflammation must be taken into consideration when utilizing this murine model of synchronized colitis.

关键词： colon dexamethasone histology induction inflammation knockout

Seasonal variation and host sex affect bat–bat fly interaction networks in the Amazonian savannahs

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Integrative Zoology 2024年第3期19卷 400-416页

作者： Paulo MEJIA Gustavo Lima URBIETA Bruna da Silva XAVIER IsaíJorge de CASTRO JoséJúlio DE TOLEDO Gustavo GRACIOLLI Lucio AndréVIANA DIAS William douglas CARVALHO Programa de Pós-Graduação em Biodiversidade Tropical Universidade Federal do Amapá(UNIFAP)MacapáAPBrazil Programa de Pós-Graduação em Ecologia Instituto de BiologiaCentro de Ciências da SaúdeUniversidade Federal do Rio de Janeiro(UFRJ)Rio de JaneiroRJBrazil Laboratório de Mamíferos Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá(IEPA)MacapáAPBrazil Programa de Pós-Graduação em Biologia Animal Laboratório de SistemáticaEcologia e Evolução(LSEE)Instituto de BiociênciasUniversidade Federal de Mato Grosso do Sul(UFMS)Campo GrandeMTBrazil Terrestrial Ecology Group(TEG-UAM) Departamento de EcologíaFacultad de CienciasUniversidad Autónoma de MadridMadridSpain Centro de Investigación en Biodiversidad y Cambio Global(CIBC-UAM) Universidad Autónoma de MadridMadridSpain

Bats are the second-most diverse group of mammals in the world,and bat flies are their main ***,significant knowledge gaps remain regarding these antagonistic interactions,especially since diverse factors such as seasonality and host sex can affect their network ***,we explore the influence of such factors by comparing species richness and composition of bat flies on host bats,as well as specialization and modularity of bat–bat fly interaction networks between seasons and adult host *** captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of AmapáState,northeastern region of the Brazilian *** female bats being more parasitized and recording greater bat fly species richness in the wet season,neither relationship was statistically *** pooled network could be divided into 15 compartments with 54 links,and all subnetworks comprised>12 *** total number of links ranged from 27 to 48(for the dry and wet seasons,respectively),and female and male subnetworks had 44 and 41 links,*** values were very low for the pooled network and for all *** results revealed higher bat fly species richness and abundance in the wet season,whereas specialization and modularity were higher in the dry ***,the subnetwork for female bats displayed higher specialization and modularity than the male ***,both seasonality and host sex contribute in different ways to bat–bat fly network *** studies should consider these factors when evaluating bat–bat fly interaction networks.

关键词： Amapá Amazon biome bat flies bats interaction networks

Manipulation of photosensory and circadian signaling restricts phenotypic plasticity in response to changing environmental conditions in Arabidopsis

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Molecular Plant 2024年第9期17卷 1458-1471页

作者： martin William Battle Scott Fraser Ewing Cathryn Dickson Joseph Obaje Kristen N.Edgeworth Rebecca Bindbeutel Rea LAntoniou-Kourounioti Dmitri A.Nusinow Matthew Alan Jones Plant Science Group School of Molecular BiosciencesUniversity of GlasgowGlasgow G128QQUK Danforth Plant Science Center St.LouisMO 63132USA Department of Biological and Biomedical Sciences Washington University in St.LouisSt.LouisMO 63130USA Present address:School of Biological and Environmental Sciences Liverpool John Moores UniversityLiverpool L22QPUK

Plants exploit phenotypic plasticity to adapt their growth and development to prevailing environmental *** of light and temperature signals is aided by the circadian system,which provides a temporal *** plasticity provides a selective and competitive advantage in nature but is obstructive during large-scale,intensive agricultural practices since economically important traits(including vegetative growth and flowering time)can vary widely depending on local environmental *** prevents accurate prediction of harvesting times and produces a variable *** this study,we sought to restrict phenotypic plasticity and circadian regulation by manipulating signaling systems that govern plants'responses to environmental *** modeling of plant growth and develop-ment predicted reduced plant responses to changing environments when circadian and light signaling pathways were *** tested this prediction by utilizing a constitutively active allele of the plant photoreceptor phytochrome B,along with disruption of the circadian systemvia mutation of *** found that these manipulations produced plants that are less responsive to light and temper-ature cues and thus fail to anticipate *** engineered plants have uniform vegetative growth and flowering time,demonstrating how phenotypic plasticity can be limited while maintaining plant *** has significant implications for future agriculture in both open fields and controlled environments.

关键词： circadian developmental plasticity phenotypic plasticity external coincidence light temperature

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银河系搭车客指南

英语画刊(高中版) 2024年第10期 16-19页

作者： douglas Adams

《银河系搭车客指南》是一部由英国著名科幻小说家道格拉斯·亚当斯创作的科幻小说。地球要被毁灭了,因为它所在的地方将修建一条超空间快速通道。主人公亚瑟·邓特和朋友福特活了下来,而福特其实是个外星人,是名著《银河系搭车客指南...

《银河系搭车客指南》是一部由英国著名科幻小说家道格拉斯·亚当斯创作的科幻小说。地球要被毁灭了,因为它所在的地方将修建一条超空间快速通道。主人公亚瑟·邓特和朋友福特活了下来,而福特其实是个外星人,是名著《银河系搭车客指南》派赴地球的研究员。两人开始了一场穿越银河的冒险,能够帮助他们的只有《银河系搭车客指南》一书中所包含的无限智慧。本文为节选。

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Effects of Papyrus Plants (Cyperus papyrus) on the Physicochemical Parameters and Nutrient Levels of Water and Sediments in Yala Swamp Wetland in Western Kenya

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Journal of Biophysical Chemistry 2024年第1期15卷 1-23页

作者： Violet Achieng Orodo Paul Otieno Abuom Emmanuel Amukohe Shikanga Elly Tetty Osewe douglas Nyambane Anyona Fredrick Mhina Mngube Stephen Adongo Odongo Department of Environmental Studies Maseno University Kisumu Kenya Department of Chemistry Maseno University Kisumu Kenya Department of Physical and Biological Sciences Murang’a University of Technology Murang’a Kenya Wetlands International Dar es Salaam Tanzania Department of Physical Sciences Jaramogi Oginga Odinga University of Science and Technology Bondo Kenya

Yala swamp wetland is the largest fresh water wetland ecosystem in Kenya supporting a broad biodiversity. It comprises of River Yala, the Yala swamp, Lakes Kanyaboli, Namboyo and Sare, and a portion of Lake Victoria neighboring the swamp. Approximately 2300 ha of land have been reclaimed and has been used for large-scale agriculture resulting in mass destruction of papyrus to create room for framing. Papyrus are known to be important in phytoremediation but despite this role information is limited, lacks supportive evidence and the empirical aspect on the levels of these pollutants in relation to the papyrus biomass is limited. The study is aimed at determining the effects of Cyperus papyrus on the water and sediment quality in Yala Swamp wetland. Six sampling sites were purposefully selected to monitor the variations of the physicochemical parameters (temperature, dissolved oxygen: DO, pH, biological oxygen demand: BOD, total suspended solids: TSS, turbidity, electrical conductivity: EC and total dissolved solids: TSS) and the levels selected nutrients (phosphorus and nitrates) in water and sediments as River Yala flows through Dominion Farms, Lake Sare which surrounded by Cyperus papyrus and finally into Lake Victoria. The samples were collected in triplicates during the wet and dry seasons (May and September 2015 respectively). The physicochemical parameters were measured in situ using a Hydrolab muiltimeter while the nutrients were analyzed using UV/Vis spectroscopy. Statistical analysis was done using SAS V9.0 software. The mean temperature was 26.19˚C ± 0.71˚C, DO: 3.72 ± 1.02 Mg/l, BOD: 3.9 ± 0.32 Mg/l, pH: 7.52 ± 0.17, TDS: 109 ± 86.33, EC: 173.26 ± 13.8 μS/cm, TSS: 12.42 ± 18.51 Mg/l and Turbidity: 12.29 ± 10.03 NTU. The values varied significantly at P 0.05 among all the sites. The results show that papyrus is useful in maintaining the required levels of physicochemical parameters. The study will assist in conservation of the papyrus to help phytoremediate

关键词： Adsorbing Contaminants Phytoremediation Conservation Cyperus papyrus