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A Study of the TPS Based Beam-Matching Concept for Medical Linear Accelerators at a Tertiary Hospital

International j.urnal of Medical Physics, Clinical Engineering and Radiation Oncology 2024年第1期13卷 16-25页

作者： Ntombela N. Lethukuthula Rovetto j. Nicolas Nethwadzi C. Lutendo Mpumelelo Nyathi Department of Radiation Oncology Steve Biko Academic Hospital Pretoria South Africa Department of Medical Physics University of Pretoria Pretoria South Africa Department of Medical Physics Sefako Makgatho Health Sciences University Ga-Rankuwa South Africa

The flexibility in radiotherapy can be improved if patients can be moved between any one of the department’s medical linear accelerators (LINACs) without the need to change anything in the patient’s treatment plan. For this to be possible, the dosimetric characteristics of the various accelerators must be the same, or nearly the same. The purpose of this work is to describe further and compare measurements and parameters after the initial vendor-recommended beam matching of the five LINACs. Deviations related to dose calculations and to beam matched accelerators may compromise treatment accuracy. The safest and most practical way to ensure that all accelerators are within clinical acceptable accuracy is to include TPS calculations in the LINACs matching evaluation. Treatment planning system (TPS) was used to create three photons plans with different field sizes 3 × 3 cm, 10 × 10 cm and 25 × 25 cm at a depth of 4.5 cm in Perspex. Calculated TPS plans were sent to Mosaiq to be delivered by five LINACs. TPS plans were compared with five LINACs measurements data using Gamma analyses of 2% and 2 mm. The results suggest that for four out of the five LINACs, there was generally good agreement, less than a 2% deviation between the planned dose distribution and the measured dose distribution. However, one specific LINAC named “Asterix” exhibited a deviation of 2.121% from the planned dose. The results show that all of the LINACs’ performance were within the acceptable deviation and delivering radiation dose consistently and accurately.

关键词： Radiotherapy Beam-Matching Linear Accelerator Dosimetry

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Improved Analytical Methods for Determination of Residues of Nitrapyrin and 6-Chloropicolinic Acid in Different Crop Matrices by Liquid Chromatography-Tandem Mass Spectrometry

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j.urnal of Agricultural Chemistry and Environment 2024年第3期13卷 263-281页

作者： Fabiola G. Zuno-Floriano Riza L. Reyes-Punongbayan Matt j. Hengel Department of Environmental Toxicology University of California Davis California USA

Novel analytical methods were developed for the determination of nitrapyrin and 6-chloropicolinic acid (6-CPA) residues in agricultural products. Nitrapyrin was extracted with hexane: toluene (1:1, v/v) and 6-CPA with 0.1 N sodium hydroxide (NaOH). For nitrapyrin, samples were cleaned with silica solid phase extraction (SPE) and for 6-CPA with C18 or carbon SPE. Analysis was performed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) with external calibration (0.010 to 0.0010 µg∙mL−1 for nitrapyrin and 0.0050 to 0.00025 µg∙mL−1 for 6-CPA). Recoveries for nitrapyrin and 6-CPA were 68% - 102% and 66% - 90%, respectively. Nitrapyrin was detected in celery and onion (−1) and 6-CPA in onion, mustard greens and lettuce (−1). Lower level method validation (LLMV) for nitrapyrin and 6-CPA was 0.020 µg∙g−1 and 0.050 µg∙g−1, respectively. The methods presented in this study are robust and were utilized for the registration of nitrapyrin on agricultural commodities in the United States.

关键词： Herbicide Agricultural Products External Calibration LC-MS/MS Registration

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Primary and Secondary Microplastic and Nanoplastic Regulations: Perspectives on Water Industry Impacts

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j.urnal of Environmental Protection 2024年第6期15卷 697-715页

作者： Shirin Estahbanati Giridhar Upadhyaya Martha j. M. Wells Katherine Y. Bell Brown and Caldwell New York NY USA Brown and Caldwell Irvine CA USA EnviroChem Services Cookeville TN USA Brown and Caldwell Nashville TN USA

Plastic pollution, both primary and secondary, is an environmental challenge, prompting regulatory actions at global and regional levels. With increasing research about the impacts of micro- and nanoplastics on ecosystems and human health, governments worldwide have undertaken efforts to address this issue. The global community has advanced regulatory efforts that have led to the implementation of national laws or regulations in numerous countries. These measures ban or restrict the use of primary and secondary microplastics and nanoplastics. An overview of global and European regulatory frameworks is presented to provide context for the United States (US). In the endeavor to document plastics regulation development in the US, a description of regulatory agencies and their roles in advancing policy and rules as well as future direction and areas for improvement in regulating plastics are introduced. A discussion of what emerging regulations mean to utilities and industries is also provided along with a comparison of regulatory frameworks.

关键词： Microplastic Regulation Environmental Governance Plastic Pollution Mitigation Regulatory Framework

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Applications of genetic code expansion technology in eukaryotes

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Protein & Cell 2024年第5期15卷 331-363页

作者： Qiao-ru Guo Yu j.Cao State Key Laboratory of Chemical Oncogenomic Guangdong Provincial Key Laboratory of Chemical GenomicsPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China

Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to *** eukaryotes,genetic code expansion(GCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic *** is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch ***,there is keen interest in utilizing GCE in eukaryotic *** review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.

关键词： genetic code expansion unnatural amino acid eukaryotes basic research therapeutic applications

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Analysis of the inflection points of height-diameter models

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Forest Ecosystems 2024年第4期11卷 414-422页

作者： Tzeng Yih Lam Mark j.Ducey Department of Forest Resources Management Faculty of ForestryThe University of British Columbia2045-2424 Main MallVancouverBCV6T 1Z4 Canada Department of Natural Resources and the Environment University of New Hampshire114 James HallDurhamNH 03824USA

The inflection point is an important feature of sigmoidal height-diameter(H-D)*** is often cited as one of the properties favoring sigmoidal model ***,there are very few studies analyzing the inflection points of H-D *** goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional *** six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)*** models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial *** distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and *** produced some of the largest inflection *** and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree *** species or decreasing shade tolerance resulted in larger inflection *** trends in the estimated inflection points of HOS and VBR were entirely opposite across the ***,HOS could produce concave H-D curves for portions of the *** on the studied behaviors,the choice between two-parameter models may not *** recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on *** sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with *** study highlights the need to integrate analysis of inflection points into modeling H-D relationships.

关键词： Concavity Forest inventory and analysis Generalized height-diameter models Growth functions Height-diameter functions Mixed-effects modeling Points of inflection Species-specific models

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Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 819-836页

作者： D.LEE S.CHANG j.LEE Department of Automotive Engineering Hanyang UniversitySeoul 04763Republic of Korea School of Mechanical Engineering Chungnam National UniversityDaejeon 34134Republic of Korea Department of Mechanical Robotics and Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea

This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random *** method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data *** the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random *** allows for avoiding repeated computations of invariant substructures while generating the input-output data *** substructuring with static condensation further improves the computational efficiency of the reanalysis without losing ***,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional *** numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs.

关键词： forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation substructuring

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Proteins as nanomagnets and magnetoreceptors

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Zoological Research 2024年第4期45卷 831-832页

作者： P.j.Hore Department of Chemistry University of OxfordUK

It is an appealing notion that a protein molecule could act as a nanomagnet.A genetically encodable biomolecule with a permanent magnetic moment at room temperature could have a range of applications:a magnetogenetic actuator,a magnetic tag for purifying and immobilizing enzymes,a contrast agent for magnetic resonance imaging,and a basis for a biomimetic magnetic sensing device,to name j.st a few.A magnetic protein could perhaps also function as the sensor in the magnetic compass that enables small songbirds to navigate the huge distances between their breeding and wintering *** though such possibilities may be,how realistic are they?

关键词： magnetic magnets enable

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Surface engineering with ionic polymers on membranes for boron removal

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 61-69页

作者： Xiting Zhang Chenyi Fang j.Paul Chen Sui Zhang Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117576Singapore Department of Civil and Environmental Engineering National University of SingaporeSingapore 119260Singapore College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial *** research efforts performed post-modification of reverse osmosis membranes to enhance boron rej.ction,which is usually accompanied by substantial sacrifice in water *** study delves into the surface engineering of low-pressure reverse osmosis membranes,aiming to elevate boron removal efficiency while maintaining optimal salt rej.ction and water *** were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and *** surfaces became smoother and more hydrophilic after *** optimum membrane exhibited a water permeability of 9.2±0.1 L·m^(-2)·h^(-1)·bar^(-1),NaCl rej.ction of 95.8%±0.3%,and boron rej.ction of 49.7%±0.1% and 99.6%±0.3% at neutral and alkaline pH,*** water permeability is reduced by less than 15%,while the boron rej.ction is 3.7 times higher compared to the blank *** research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.

关键词： membrane low-pressure reverse osmosis boron surface engineering

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Awareness of the Termination of Pregnancy Act of the Laws of Zambia among Women of Reproductive Age at Kanyama First Level Hospital in Lusaka District Zambia

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Open j.urnal of Obstetrics and Gynecology 2024年第8期14卷 1267-1287页

作者： j. K. Botha C. C. Ngoma P. S. Munkoka Lusaka District Health Office Matero First Level Hospital Lusaka Zambia Department of Midwifery Womens and Child Health School of Nursing Sciences University of Zambia Lusaka Zambia College of Nursing and Midwifery University of Lusaka Lusaka Zambia

Background: Termination of pregnancy (TOP) in Zambia is guided by the Termination of Pregnancy (TOP) Act of 1972 and as amended in 1994 of the laws of Zambia. However, despite provision of Comprehensive abortion care services with the liberal law, statistics at Kanyama First Level Hospital in relation to unsafe illegal abortions are alarming. This study sought to understand the Awareness on the TOP Act of the laws of Zambia among women of reproductive age 15 - 49 years at Kanyama First Level Hospital in Lusaka District. Purpose of the Study: To assess awareness on the TOP Act among women of reproductive age at Kanyama First Level Hospital in Lusaka, Zambia. Methodology: A convergent parallel mixed method design was conducted using both survey and in-depth interviews among women of reproductive age at Kanyama First Level Hospital in Lusaka District. The study surveyed 370 randomly sampled women aged 15 to 49 years old while the in-depth interviews included eight women purposively sampled from the survey population. Survey data was analyzed using descriptive and inferential statistics while qualitative data thematic analysis was used. Results: The study found that 37% of the participants were aware of the TOP Act while 63.8% viewed legalization of abortion for any reason as wrong. The study results also showed that widowed women were 8 times more likely to be aware of the TOP Act compared to single women (AOR: 8.262;95% CI: 1.105, 61.778). Women in business were significantly more likely to be aware of the TOP Act compared to those who reported having no occupation. (AOR: 2.61;95% CI: 1.246, 5.499). Limited access to information, the social stigma attached to abortion, health care providers’ attitudes, cultural norms, values and religious beliefs, restrictive legal requirements, and absence of a supportive network were some of the barriers affecting awareness and utilization of available safe abortion care services. Conclusions: The research findings concluded that a

关键词： Awareness Termination of Pregnancy Act Barriers Determinants Women

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Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

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j.urnal of Rare Earths 2024年第10期42卷 1950-1959页

作者： P.A.Martínez-Montoya j.M.del Río A.de j.Morales-Ramirez M.Corea Escuela Superior de Ingeniería Química e Industrias Extractivas ESIQIE-IPNDepartamento de Ingeniería Metalúrgica UPALM S/N Col.Lindavista Escuela Superior de Ingenieria Química e Industrias Extractivas ESIQIE-IPNLaboratorio de Investigación en Polímeros y NanomaterialesUPALM S/N Col.Lindavista Centra de Investigación e Innovación Tecnológica CIITEC-IPNCda.de CECATIs/n

Polymeric nanoparticles of poly(methyl methacrylate) were obtained by emulsion polymerization techniques in a proce ss of two *** particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were *** incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR) and ultraviolet-visible(UV-Vis) *** spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(SEM).The polymeric materials were used for recovery of [Eu]from synthetic *** nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85% of [Eu] at pH of *** images of SEM after extraction process show arrays between particles with larger average particle sizes to 1.5 *** addition,the particles have a good stripping capacity,exceeding 50% of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of6.

关键词： Chelating effect Emulsion polymerization Extraction process Rare earths Stripping process [Eu]recovery

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