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Occurrence of.f.atures of.f.ber Bragg Grating Spectra Having a Wavelength Corresponding to the Phase Mask Periodicity

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Journal of.Electronic Science and Technology of.China 2008年第4期6卷 458-461页

作者： Sui P. Yam Zourab Brodzeli Scott A. Wade Greg W. Baxter stephen f. collins Optical Technology Research Laboratory Centre for Telecommunications and Microelectronics Victoria University PO Box 14428 Melbourne VIC 8001 Australia Department of.Mechanical and Aerospace Engineering Monash University Clayton VIC 3800 Australia

The use of.a phase mask with 536 nm unif.rm pitch allowed the f.brication of.a f.ber Bragg grating f.r use at a Bragg wavelength of.785 nm. Ref.ection and transmission f.atures at 1552 nm, twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than ＋1 were absent during f.brication the f.atures at 1552 nm were not evident.

关键词： Double of.the Bragg wavelength f.ber Bragg grating phase mask Talbot interf.rometer.

Plant-available water capacity of.soils at a regional scale:Analysis of.f.xed and dynamic f.eld capacities

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Pedosphere 2024年第3期34卷 590-605页

作者： Vinod PHOGAT Paul RPETRIE Casandra collins Marcos BONADA South Australian Research and Development Institute GPO Box 397Adelaide SA 5001(Australia) School of.Agriculture Food and WineWaite Research InstituteUniversity of AdelaideWaite CampusPMB1Glen Osmond SA 5064(Australia) College of.Science and Engineering Flinders UniversityBedford Park SA 5042(Australia) The University of.New South Wales Sydney NSW 2052(Australia) ARC Training Centre f.r Innovative Wine Production University of AdelaidePMB1Glen Osmond SA 5064(Australia)

Estimation of.the plant-available water capacity(PAWC)of.soils at a regional scale helps in adopting better land use planning,developing suitable irrigation schedules f.r crops,and optimizing the use of.scarce water *** the current study,72 soil prof.les were sampled f.om the Barossa region of.South Australia to estimate pedo-transf.r f.nctions deduced f.om easily estimated soil *** f.nctions were then used to estimate the f.xed(10 and 33 kPa)and dynamic pressure head(h_(f.))water contents at f.eld capacity(f.)f.r minimum drainage f.ux(0.01 and 0.001 cm d^(-1)),which serves as the upper boundary f.r plant-available water in *** estimated residual water content was corrected f.r subsoil constraints,especially the exchangeable sodium percentage(ESP).The results showed that the mean values of.h_(f.)in sand-dominated light and medium textured soils(i.e.,sand,loamy sand,sandy loam,and loam)varied in a narrow range(15.8-18.2 kPa),whereas those in the clay-dominated heavy textured soils(i.e.,clay loam)showed a wide range(11.3-49.3 kPa).There were large dif.erences in PAWC f.r dynamic f.(PAWC_(f.))and f.xed f. at 10 kPa(PAWC10),33 kPa(PAWC33),and a mix of.10and 33 kPa(PAWC_(10,33))pressure heads depending on soil ***,the dif.erence between PAWC at 10 kPa and h_(f.)(ΔPAWC_(10))was positive,whereas that between 33 kPa and h_(f.)(ΔPAWC_(33))was negative across all ***,the estimation of.PAWC assuming a f.xed f. at 10 and 33 kPa pressures(i.e.,PAWC_(10,33))f.r sandy,clay,and silty soils reduced the dif.erence between f.xed and dynamic pressure PAWCs tof.PAWC was improved by incorporating the impact of.subsoil constraints,such as high ESP,which was more pronounced f.r clay and silty *** f.ndings demonstrate the inherent inconsistencies between static pressure and f.ux-based dynamic f. estimations in *** heterogeneity,intra-texture variability,subsoil constraints,and swell

关键词： crop lower limit drained upper limit pedo-transf.r f.nction soil hydraulic parameter soil texture

地球演化历史中氧逸度变化对壳幔循环启动、风化和超大陆循环的指示

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Science Bulletin 2024年第1期69卷 97-102页

作者：王瑞邬绍宸 Roberto f.Weinberg William J.collins Peter A.Cawood State Key Laboratory of.Geological Processes and Mineral Resources Institute of Earth SciencesChina University of GeosciencesBeijing 100083China f.ontiers Science Center f.r Deep-time Digital Earth China University of Geosciences(Beijing)Beijing 100083China School of.Earth Atmosphere and EnvironmentMonash UniversityClayton VIC 3800Australia The Institute f.r Geoscience Research Curtin UniversityPerth WA 6102Australia

We apply a zircon redox index to a global compilation of.detrital zircons to track the variation of.oxidation state,expressed asΔf.Q,through Earth's *** f.om I-type rocks,which comprise mantle and crustal igneous protoliths,including tonalite–trondhjemite–granodiorites(TTGs),generally have a high oxidation state(Δf.Q>0).In contrast,zircons f.om igneous rocks derived f.om supracrustal source rocks(S-type)are commonly reduced(Δf.Qf.nction derived f.om the Gaussian-Kernel-Density-Estimation,we use the maximum likelihood estimation(MLE)to distinguish Stype f.om I-type zircons through Earth's history using zircon *** S-type magma production shows a ca.600 Ma cyclicity that is closely related to the supercontinent *** link a cyclic drop in redox values af.er 2.6 Ga to periodic S-type magma generation associated with burial and melting of.metasedimentary rocks during supercontinent assembly and ***Δf.Q of.the detrital zircons rise at~3.5 Ga f.llowed by a consistent averageΔf.Q>0 over the last 3 *** that the redox state of.magmas is independent of.crustal thickness and silica variation,and elevated values are likely more closely related to tectonic setting,we suggest that the consistent averageΔf.Q>0 f.om ca.3.5 Ga onwards relates to recycling of.oceanic lithosphere back into the mantle in what eventually became established as subduction *** more reduced magmas associated with sedimentary sources,became established at 2.6 Ga,presumably in response to continental rocks rising above sealevel,and f.llow peaks of.productivity associated with the supercontinent cycle.

关键词： Oxidation state Supercontinent Weathering Subduction Zircon Granite

Development and characterization of.3D-printed electroconductive pHEMA-co-MAA NP-laden hydrogels f.r tissue engineering

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Bio-Design and Manuf.cturing 2024年第3期7卷 262-276页

作者： Sara De Nitto Aleksandra Seraf.n Alexandra Karadimou Achim Schmalenberger John J.EMulvihill Maurice N.collins DIBRIS Polytechnic Inter-School Section University of Genoa16126 GenoaItaly School of.Engineering Bernal InstituteUniversity of LimerickLimerick V94 T9PXIreland School of.Natural Sciences Department of Biological SciencesUniversity of LimerickLimerick V94 T9PXIreland Health Research Institute University of LimerickLimerick V94 T9PXIreland AMBER University of LimerickLimerick V94 T9PXIreland

Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs f.r diseased tissue replacement and tissue *** this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)*** presence of.the NPs was critical as they altered the rheological properties during ***,all samples exhibited suitable shear thinning properties,allowing f.r the development of.an optimized processing window f.r 3D *** were 3D printed into pre-determined disk-shaped conf.gurations of.2 and 10 mm in height and diameter,*** observed that the NPs disrupted the gel crosslinking ef.iciencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 *** conductivity of.the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/*** vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and prolif.ration ***,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels af.ected bacterial *** together,these materials show promise f.r various TE strategies.

关键词： Conductive nanoparticles Hydroxyethyl methacrylate(HEMA) Ultraviolet(UV)polymerization 3D printing

RANKL inhibition reduces lesional cellularity and Gαs variant expression and enables osteogenic maturation in f.brous dysplasia

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Bone Research 2024年第1期12卷 165-179页

作者： Luis f.de Castro Jarred M.Whitlock Zachary Michel Kristen Pan Jocelyn Taylor Vivian Szymczuk Brendan Boyce Daniel Martin Vardit Kram Rebeca Galisteo Kamran Melikov Leonid V.Chernomordik Michael T.collins Alison M.Boyce Skeletal Disorders and Mineral Homeostasis Section National Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMDUSA Section on Membrane Biology Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA Metabolic Bone Disorders Unit National Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMDUSA Department of.Plastic and Reconstructive Surgery The Johns Hopkins Medical InstitutionsBaltimoreMDUSA Department of.Pathology and Laboratory Medicine University of Rochester Medical CenterRochesterNYUSA NIDCR Genomics and Computational Biology Core National Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMDUSA

f.brous dysplasia(f.)is a rare,disabling skeletal disease f.r which there are no established *** evidence supports inhibiting the osteoclastogenic f.ctor receptor activator of.nuclear kappa-B ligand(RANKL)as a potential treatment *** this study,we investigated the mechanisms underlying RANKL inhibition in f. tissue and its likely indirect ef.ects on osteoprogenitors by evaluating human f. tissue pre-and post-treatment in a phase 2 clinical trial of.denosumab(NCT03571191)and in murine in vivo and ex vivo preclinical *** analysis of.human and mouse tissue demonstrated increased osteogenic maturation,reduced cellularity,and reduced expression of.the pathogenic Gαs variant in f. lesions af.er RANKL *** sequencing of.human and mouse tissue supported these *** interaction between osteoclasts and mutant osteoprogenitors was f.rther assessed in an ex vivo lesion model,which indicated that the prolif.ration of.abnormal f. osteoprogenitors was dependent on *** results f.om this study demonstrated that,in addition to its expected antiosteoclastic ef.ect,denosumab reduces f. lesion activity by decreasing f. cell prolif.ration and increasing osteogenic maturation,leading to increased bone f.rmation within *** f.ndings highlight the unappreciated role of.cellular crosstalk between osteoclasts and preosteoblasts/osteoblasts as a driver of.f. pathology and demonstrate a novel mechanism of.action of.denosumab in the treatment of.bone disease.

关键词： dysplasia treatment f.nding

Evaluation of.Dosimetric Impact of.Uncertainty of.Measurement in Estimating External Radiotherapy Dose

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Open Journal of.Applied Sciences 2024年第8期14卷 1985-1995页

作者： collins Omondi Margaret Chege Samson Omondi Physics Department Kenyatta University Nairobi Kenya College of.Health Physics Jomo Kenyatta University of Agriculture and Technology Juja Kenya

Cancer is a major societal public health and economic problem, responsible f.r one in every six deaths. Radiotherapy is the main technique of.treatment f.r more than half.of.cancer patients. To achieve a successf.l outcome, the radiation dose must be delivered accurately and precisely to the tumor, within ± 5% accuracy. Smaller uncertainties are required f.r better treatment outcome. The objective of.the study is to investigate the uncertainty of.measurement of.external radiotherapy beam using a standard ionization chamber under ref.rence conditions. Clinical f.rmers type ionization chamber measurement was compared against the National Ref.rence standard, by exposing it in a beam 60Co gamma source. The measurement set up was carried out according to IAEA TRS 498 protocol and uncertainty of.measurement evaluated according to GUM TEDDOC-1585. Evaluation and analysis were done f.r the identif.ed subjects of.uncertainty contributors. The expanded uncertainty associated with 56 mGy/nC ND,W was f.und to be 0.9% corresponding to a conf.dence level of.approximately 95% with a coverage f.ctor of.k = 2. The study established the impact of.dosimetry uncertainty of.measurement in estimating external radiotherapy dose. The investigation established that the largest contributor of.uncertainty is the stability of.the ionization chamber at 36%, f.llowed by temperature at 22% and positioning of.the chamber in the beam at 8%. The ef.ect of.pressure, electrometer, resolution, and reproducibility were f.und to be minimal to the overall uncertainty. The study indicate that there is no f.awless measurement, as there are many prospective sources of.variation. Measurement results have component of.unreliability and should be regarded as best estimates of.the true value. .

关键词： Absorbed Dose to Water Radiotherapy Uncertainty of.Measurement Secondary Standards Dosimetry Laboratory Ionizing Chamber

Assessment of.Occupational Radiation Exposure f.r Radiotherapy Healthcare Workers at Kenyatta National Hospital Using Thermoluminescence Dosimeter Lif.Mg,Ti

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Journal of.Geoscience and Environment Protection 2024年第7期12卷 14-24页

作者： collins Omondi Margaret Chege Samson Omondi Department of.Physics Kenyatta University Nairobi Kenya College of.Health Physics Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

Kenyatta National Hospital (KNH) is the largest public ref.rral hospital with a comprehensive cancer treatment f.cility in East and Central Af.ica. Occupational radiation monitoring is a signif.cant technique f.r demonstrating compliance of.radiation regulatory limits. The objective of.the study was to carry out assessment of.occupational radiation exposure among radiotherapy personnel at KNH using thermoluminescence dosimeter, TLD. KNH staf. were monitored using dosimeter type TLD-100 made of.Lif.Mg,Ti, on monthly basis. The reader system used f.r analysis was Harshaw 8800. The measurement established the average monthly accumulated occupational personnel dose f.r KNH to be 0.21 mSv and 0.29 mSv f.r Hp (10) and Hp (0.07) respectively. The accumulated dose results were within the maximum acceptable dose of.1.67 mSv/month and 41.6 mSv/month f.r Hp (10) and Hp (0.07) respectively. The investigation results were higher than the acceptable public limit of.0.08 mSv/month. Moreover, incidences were noted where the f.tus dose limit 0.42 was also exceeded. Evaluation of.statistical dose exposure among doctors, nurses and radiographers’ measurement results were within ±0.02 mSv. The study established the average KNH occupational radiation exposure levels f.r both Hp (10) and Hp (0.07) were within the ICRU recommendation, validating radiation protection saf. practice. Data analysis of.healthcare workers did not indicate exposure trend biased to any healthcare prof.ssion. Hence radiation risk cut across all prof.ssional categories. It is recommended that Radiation Monitoring program be reviewed to include non-clinical staf. who access the f.cility. Radiation reporting should not be limited to one f.cility, but ref.ect cases where workers are involved in multiple multiple jobs.

关键词： Occupational Monitoring Exposure Thermoluminescence Dosimeter and Radiotherapy

Evaluation of.Air-Kerma and Absorbed Dose to Water f.r External Radiotherapy Beam Using Ionization Chamber

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Open Journal of.Radiology 2024年第3期14卷 113-124页

作者： collins Omondi Margaret Chege Samson Omondi Kenyatta University Nairobi Kenya Jomo Kenyatta University of.Agriculture and Technology Nairobi Kenya

Radiotherapy is the most widely applied oncologic treatment modality utilizing ionizing radiation. A high degree of.accuracy, reliability and reproducibility is required f.r a successf.l treatment outcome. Measurement using ionization chamber is a prerequisite f.r absorbed dose determination f.r external beam radiotherapy. Calibration coef.icient is expressed in terms of.air kerma and absorbed dose to water traceable to Secondary Standards Dosimetry Laboratory. The objective of.this work was to evaluate the level of.accuracy of.ionization chamber used f.r clinical radiotherapy beam determination. Measurement and accuracy determination were carried out according to IAEA TRS 398 protocol. Clinical f.rmers type ionization chamber measurement and National Ref.rence standard f.om Secondary Standards Dosimetry Laboratory were both exposed to cobalt-60 beam and measurement results compared under the same environmental conditions. The accuracy level between National Ref.rence Standard and clinical radiotherapy standard was f.und to be −1.92% and −2.02% f.r air kerma and absorbed dose to water respectively. To minimize the ef.ect of.error and maximize therapeutic dose during treatment in order to achieve required clinical outcome, calibration f.ctor was determined f.r air kerma (Nk) as 49.7 mGy/nC and absorbed dose to water ND, as 52.9 mGy/nC. The study established that radiotherapy beam measurement chain is prone to errors. Hence there is a need to independently verif. the accuracy of.radiation dose to ensure precision of.dose delivery. The errors must be accounted f.r during clinical planning by f.ctoring in calibration f.ctor to minimize the systematic errors during treatment, and thereby providing enough room to achieve ±5% dose delivery to tumor target as recommended by ICRU.

关键词： Absorbed Dose to Water Air Kerma Co-60 Source Calibration SSDL Radiotherapy Beam Metrology Accuracy and Accuracy

地球演化历史中氧逸度变化对壳幔循环启动、风化和超大陆循环的指示（英文）

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Science Bulletin 2024年第1期 97-102页

作者：王瑞邬绍宸 Roberto f.Weinberg William J.collins Peter A.Cawood State Key Laboratory of.Geological Processes and Mineral Resources Institute of Earth Sciences China University of Geosciences f.ontiers Science Center f.r Deep-time Digital Earth China University of Geosciences (Beijing) School of.Earth Atmosphere and Environment Monash University The Institute f.r Geoscience Research Curtin University

We apply a zircon redox index to a global compilation of.detrital zircons to track the variation of.oxidation state, expressed as Δf.Q, through Earth’s history. Those f.om I-type rocks, which comprise mantle and crustal igneous protoliths, including tonalite–trondhjemite–granodiorites(TTGs), generally have a high oxidation state(Δf.Q > 0). In contrast, zircons f.om igneous rocks derived f.om supracrustal source rocks(S-type) are commonly reduced(Δf.Q f.nction derived f.om the Gaussian-Kernel-Density-Estimation, we use the maximum likelihood estimation(MLE) to distinguish Stype f.om I-type zircons through Earth’s history using zircon redox. Voluminous S-type magma production shows a ca. 600 Ma cyclicity that is closely related to the supercontinent cycle. We link a cyclic drop in redox values af.er 2.6 Ga to periodic S-type magma generation associated with burial and melting of.metasedimentary rocks during supercontinent assembly and amalgamation. The Δf.Q of.the detrital zircons rise at ～3.5 Ga f.llowed by a consistent average Δf.Q > 0 over the last 3 Ga. Given that the redox state of.magmas is independent of.crustal thickness and silica variation, and elevated values are likely more closely related to tectonic setting, we suggest that the consistent average Δf.Q > 0 f.om ca.3.5 Ga onwards relates to recycling of.oceanic lithosphere back into the mantle in what eventually became established as subduction zones. The more reduced magmas associated with sedimentary sources, became established at 2.6 Ga, presumably in response to continental rocks rising above sealevel, and f.llow peaks of.productivity associated with the supercontinent cycle.

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