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Assessing efficacy of standard impregnation techniques on die-cast aluminum alloys using X-ray micro-CT

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China Foundry 2024年第3期21卷 276-286页

作者： Ajith Bandara Koichi Kan Katanaga Yusuke Natsuto Soga Akifumi Koike Toru Aoki Hamamatsu TSC Chuo Hatsumei Institute322 lida-choMinami-kuHamamatsu435-0028Japan Graduate School of Medical Photonics ShizuokaUniversityJohoku 3-5-1HamamatsuShizuoka432-8561Japan ANSeeN Inc Johoku 3-5-1HamamatsuShizuoka432-8561Japan Research Institute of Electronics ShizuokaUniversityJohoku 3-5-1HamamatsuShizuoka432-8561Japan

Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak *** pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al *** this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCT)and a standard leak *** results demonstrate that the commonly used water leak test is insufficient for determining the sealing ***,micro XCT shows distinct advantages by enabling more comprehensive *** reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in *** effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray *** research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals.

关键词： nondestructive testing Al alloy die-casting vacuum pressure impregnation micro X-ray computed tomography duel-energy X-ray CT

Current and future trends in whole genome sequencing in cancer

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Cancer Biology & Medicine 2024年第1期21卷 16-20页

作者： Yuki Katsuya Department of Experimental Therapeutics National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyo 104-0045Japan

Cancer remains a formidable global health challenge affecting millions of lives *** decades,conventional cancer treatments used a one-size-fits-all approach,overlooking the intricate genetic variations that drive *** emergence of cancer genomics has ushered in a new era of personalized and targeted cancer *** Human Genome Project,which was launched in 1990 and completed in 2003。

关键词： cancer Cancer annually

Distributed phase-matching measurement for dynamic strain and temperature sensing based on stimulated Brillouin scattering enhanced four-wave mixing

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Photonics Research 2024年第1期12卷 141-153页

作者： YUAN WANG PEDRO TOVAR JUNTONG YANG LIANG CHEN XIAOYI BAO Nexus for Quantum Technologies University of OttawaOttawaOntario K1N 6N5Canada

A Brillouin dynamic grating(BDG) can be used for distributed birefringence measurement in optical fibers,offering high sensitivity and spatial resolution for sensing ***,it is quite a challenge to simultaneously achieve dynamic measurements with both high accuracy and high spatial *** this work,we propose a sensing mechanism to achieve distributed phase-matching measurement using a chirped pulse as a probe *** BDG reflection,the peak reflection corresponds to the highest four-wave mixing(FWM) conversion efficiency,and it requires the Brillouin frequency in the fast and slow axes to be equal,which is called the phase-matching *** condition changes at different fiber positions,which requires a range of frequency injection for the probe *** proposed method uses a chirped pulse as a probe wave to cover this frequency range associated with distributed birefringence *** allows us to detect distributed phase matching for birefringence changes that are introduced by temperature and strain *** to the single shot and direct time delay measurement capability,the acquisition rate in our system is only limited by the fiber ***,unlike conventional BDG spectrum recovery-based systems,the spatial resolution here is determined by both the frequency chirping rate of the probe pulse and the birefringence profile of the *** the experiments,an acquisition rate of 1 k Hz(up to fiber length limits) and a spatial resolution of 10 cm using a 20 ns probe pulse width are *** minimum detectable temperature and strain variation are 5.6 mK and 0.37 με along a 2 km long polarization-maintaining fiber(PMF).

关键词： fiber scattering polarization

A preliminary study on rectal dose reduction associated with hyaluronic acid implantation in brachytherapy for prostate cancer

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Asian Journal of Urology 2024年第2期11卷 286-293页

作者： Tairo Kashihara Yuka Urago Hiroyuki Okamoto Mihiro Takemori Hiroki Nakayama Shohei Mikasa Tetsu Nakaichi Kotaro Iijima Takahito Chiba Junichi Kuwahara Satoshi Nakamura Weishan Chang Yoshiyuki Matsui Hiroshi Igaki Department of Radiation Oncology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Radiation Safety and Quality Assurance Division National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Department of Radiological Sciences Graduate School of Human Health SciencesTokyo Metropolitan University7-2-10 Higashi-OguArakawa-kuTokyoJapan Department of Radiological Technology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Department of Urological Oncology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan

Objectives: Hydrogel spacer (HS) was developed to reduce rectal toxicities caused by radiotherapy, but has been reported to cause major adverse events. Our institute has attempted to introduce a hyaluronic acid (HA) as an alternative spacer. This study aimed to compare rectal doses and geometric distributions between the HS and HA implantation in prostate ***: HS and HA were inserted in 20 and 18 patients undergoing high-dose brachytherapy, respectively. The rectum spacer volumes injected were 10 mL and 22 mL, respectively. In the treatment planning system, 13.5 Gy was administered with common catheter positions. The rectal dose indices were assessed between the spacer groups for dosimetry evaluation. Distances between the prostate and rectum and configurations of the spacers were ***: The mean doses irradiated to 0.1 and 2 mL of the rectum were 10.45 Gy and 6.71 Gy for HS, and 6.73 Gy and 4.90 Gy for HA (p1). The mean minimum distances between the prostate and rectum were 1.23 cm and 1.79 cm for HS and HA, respectively (p5). Geometrical configuration comparisons revealed that HA has a higher ability to expand the space than ***: The rectal dose reduction ability of HA is significantly greater than that of HS, suggesting its potential as a new spacer.

关键词： Brachytherapy Hyaluronicacid Hydrogel Prostaticneoplasm Radiotherapy

Spatio-Temporal Service Analysis in Multi-Layer Non-Terrestrial Networks

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Journal of Communications and Information Networks 2024年第1期9卷 43-55页

作者： Qian Chen Weixiao Meng Shuai Han Cheng Li School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China School of Engineering Science Simon Fraser UniversityBurnabyBC V5A 1S6Canada Department of Electrical and Computer Engineering Memorial UniversitySt.John’sNL A1B 3X5Canada

In the advent of the 6G era, non-terrestrial networks (NTN) with expansive coverage are being increasingly recognized as a vital supplement to cellular networks for facilitating seamless communication. The intricate interplay between network performance and service quality necessitates a thorough investigation into the modeling and analysis of services for efficient construction of *** studies on service analysis, predominantly focused on terrestrial networks,fall short in addressing the unique challenges posed by NTN,particularly those related to platform distribution and antenna gain modeling. This deficiency in research,coupled with the varying preferences of users for different network types, forms the basis of this study. This paper explores the spatio-temporal characteristics of services within a multi-layered NTN *** this context,the spatial distribution of the platforms is modeled using a binomial point process, and the antennas are characterized by a sectorized beam pattern. We derive the closed-form expressions for the association probability,the number of accessed users, and the arrival rate of services with certain delay requirements towards different types of NTN. Simulation results are provided to evaluate the influence of various parameters on the association probability, the number of accessed users, and the total arrival rate of services. The number of satellites can be determined to achieve the optimal system utility,balancing the accessed services, offloading effects, and launching costs. This initial investigation lays the groundwork for further theoretical progress in the service analysis and platform deployment of NTN.

关键词： association strategy non-terrestrial networks service analysis stochastic geometry system utility

An emerging terpolymeric nanoparticle pore former as an internal recrystallization inhibitor of celecoxib in controlled release amorphous solid dispersion beads:Experimental studies and molecular dynamics analysis

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Acta Pharmaceutica Sinica B 2024年第6期14卷 2669-2684页

作者： Jamie Anne Lugtu-Pe Xuning Zhang Sako Mirzaie Hao Han R.Chang Nour AL-Mousawi Kuan Chen Yongqiang Li Anil Kane Daniel Bar-Shalom Xiao Yu Wu Advanced Pharmaceutics and Drug Delivery Laboratory Leslie Dan Faculty of PharmacyUniversity of TorontoToronto M5S 3M2Canada Candoo Pharmatech Company Inc. Mississauga L5N 5M1Canada Department of Pharmacy University of CopenhagenCopenhagen DK-2100Denmark Patheon by Thermo Fisher Scientific Toronto Region Operations(TRO)Mississauga L5N 3X4Canada

Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution ***,most new chemical entities exhibit poor water solubility,and hence are exempt from such *** combining drug amorphization with controlled release formulation is promising to elevate drug solubility,like other supersaturating systems,the problem of drug recrystallization has yet to be resolved,particularly within the dosage ***,we explored the potential of an emerging,non-leachable terpolymer nanoparticle(TPN)pore former as an internal recrystallization inhibitor within controlled release amorphous solid dispersion(CRASD)beads comprising a poorly soluble drug(celecoxib)reservoir and insoluble polymer(ethylcellulose)*** to conventional pore former,polyvinylpyrrolidone(PVP),TPN-containing membranes exhibited superior structural integrity,less crystal formation at the CRASD bead surface,and greater extent of celecoxib ***-atom molecular dynamics analyses revealed that in the presence of TPN,intra-molecular bonding,crystal formation tendency,diffusion coefficient,and molecular flexibility of celecoxib were reduced,while intermolecular H-bonding was increased as compared to *** work suggests that selection of a pore former that promotes prolonged molecular separation within a nanoporous controlled release membrane structure may serve as an effective strategy to enhance amorphicity preservation inside CRASD.

关键词： Controlled release amorphous solid dispersion Poorly soluble drug Internal recrystallization Membrane-reservoir coated beads Molecular dynamics simulation Effect of pore formers Terpolymer nanogel Drug-polymer interactions

Hydrodynamic Assessment of A New Nature-Based Armour Unit on Rubble Mound Breakwater for Coastal Protection

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China Ocean Engineering 2024年第3期38卷 439-452页

作者： Ehsan SAFA Alireza MOJTAHEDI Abdolmajid MOHAMMADIAN Mohamad Ali Lotfollahi YAGHIN Department of Water Resources Engineering Faculty of Civil EngineeringUniversity of TabrizTabriz ***Iran Faculty of Civil Engineering University of OttawaOttawa K1H 8M5Canada

This research proposes a novel nature-based design of a new concrete armour unit for the cover layer of a rubblemoundbreakwater. Armour units are versatile with respect to shape, orientation, surface condition details, and ***, a detailed analysis is required to investigate the exact state of their hydraulic interactions and structuralresponses. In this regard, the performance results of several traditional armour units, including the Antifer cube,Tetrapod, X-block and natural stone, are considered for the first step of this study. Then, the related observed resultsare compared with those obtained for a newly designed (artificial coral) armour unit. The research methodology utilizesthe common wave flume test procedure. Furthermore, several verified numerical models in OpenFOAM code areused to gain the extra required data. The proposed armour is configured to provide an effective shore protection as anenvironmental-friendly coastal structure. Thus it is designed with a main trunk including deep grooves to imitate thetypical geometry of a coral type configuration, so as to attain desirable performance. The observed results and ananalytic hierarchy process (AHP) concept are used to compare the hydraulic performance of the studied traditionaland newly proposed (artificial coral) armour units. The results indicate that the artificial coral armour unit demonstratesacceptable performance. The widely used traditional armour units might be replaced by newer designs for betterwave energy dissipation, and more importantly, for fewer adverse effects on the marine environment.

关键词： rubble mound breakwater hydraulic interaction armour unit analytic hierarchy process numerical model

Active self-training for weakly supervised 3D scene semantic segmentation

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Computational Visual Media 2024年第3期10卷 425-438页

作者： Gengxin Liu Oliver van Kaick Hui Huang Ruizhen Hu College of Computer Science&Software Engineering Shenzhen UniversityShenzhen 518060China School of Computer Science Carleton UniversityOttawa K1S 5B6Canada

Since the preparation of labeled datafor training semantic segmentation networks of pointclouds is a time-consuming process, weakly supervisedapproaches have been introduced to learn fromonly a small fraction of data. These methods aretypically based on learning with contrastive losses whileautomatically deriving per-point pseudo-labels from asparse set of user-annotated labels. In this paper, ourkey observation is that the selection of which samplesto annotate is as important as how these samplesare used for training. Thus, we introduce a methodfor weakly supervised segmentation of 3D scenes thatcombines self-training with active learning. Activelearning selects points for annotation that are likelyto result in improvements to the trained model, whileself-training makes efficient use of the user-providedlabels for learning the model. We demonstrate thatour approach leads to an effective method that providesimprovements in scene segmentation over previouswork and baselines, while requiring only a few userannotations.

关键词： semantic segmentation weakly supervised self-training active learning

Orthogonal polynomial expansions for the valuation ofoptions under the stochastic volatility models with stochastic correlation

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Journal of Management Science and Engineering 2024年第2期9卷 239-253页

作者： Kevin Z.Tong Department of Mathematics and Statistics University of Ottawa585 King EdwardOttawaOntarioK1N 6N5Canada

This work provides a new method for pricing options under the generalized stochastic volatility models with Jacobi stochastic *** method is based on the observation that the generalized models belong to the class of polynomial diffusions and therefore the option prices can be efficiently computed via orthogonal polynomial *** take the Heston and Schöbel-Zhu models with stochastic correlation as two specific examples and are able to derive the analytical formulas for the option *** also illustrate the accuracy of the proposed method through a number of numerical experiments.

关键词： Orthogonal polynomial expansions Polynomial diffusions Stochastic correlation Jacobi process Stochastic volatility