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Persistent organic pollutants in global surface soils:Distributions and fractionations

Environmental Science and Ecotechnology 2024年第2期18卷 13-27页

作者： Yi-Fan Li Shuai Hao wan-Li Ma Pu-Fei Yang wen-Long Li Zi-Feng Zhang Li-Yan Liu robie wmacdonald International Joint Research Center for Persistent Toxic Substances(IJRC-PTS) State Key Laboratory of Urban Water Resource and EnvironmentHarbinInstitute of TechnologyHarbin150090China International Joint Research Center for Arctic Environment and Ecosystem(IJRC-AEE) Polar AcademyHarbin Institute of Technology(PA-HIT)Harbin150090China Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem(HPKL-PEE) Harbin150090China IJRC-PTS-NA TorontoONM2J 3N8Canada College of the Environment and Ecology Xiamen UniversityXiamenChina Institute of Ocean Sciences Department of Fisheries and OceansP.O.Box 6000SidneyBCV8L 4B2Canada Centre for Earth Observation Science University of ManitobaWinnipegR3T 2N2Canada

The distribution and fractionation of persistent organic pollutants(POPs)in different matrices refer to how these pollutants are dispersed and separated within various environmental *** is a significant study area as it helps us understand the transport efficiencies and long-range transport potentials of POPs to enter remote areas,particularly polar *** study provides a comprehensive review of the progress in understanding the distribution and fractionation of *** focus on the contributions of four intermedia processes(dry and wet depositions for gaseous and particulate POPs)and determine their transfer between air and *** processes are controlled by their partitioning between gaseous and particulate phases in the *** distribution patterns and fractionations can be categorized into primary and secondary *** are developed to quantificationally study the primary and secondary distributions and fractionations of *** analysis results suggest that the transfer of low molecular weight(LMw)POPs from air to soil is mainly through gas diffusion and particle deposition,whereas high molecular weight(HMw)POPs are mainly via particle ***-POPs tend to be trapped near the source,whereas LMw-POPs are more prone to undergo long-range atmospheric *** crucial distinction elucidates the primary reason behind their temperatureindependent primary ***,the secondary distribution and fractionation can only be observed along a temperature gradient,such as latitudinal or altitudinal *** animation is produced by a one-dimensional transport model to simulate conceptively the transport of CB-28 and CB-180,revealing the similarities and differences between the primary and secondary distributions and *** suggest that the decreasing temperature trend along latitudes is not the major reason for POPs to be fractionated into the polar ecosystems,but drives the longer-term accumu

关键词： POPs Primary and secondary sources Primary and secondary emissions Primary and secondary distribution patterns Primary and secondary fractionations

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Modeling historical budget for β-Hexachlorocyclohexane(HCH)in the Arctic Ocean:A contrast to α-HCH

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Environmental Science and Ecotechnology 2023年第2期14卷 18-28页

作者： Pu-Fei Yang robie w.macdonald Hayley Hung Derek C.G.Muir Roland Kallenborn Anatoly N.Nikolaev wan-Li Ma Li-Yan Liu Yi-Fan Li International Joint Research Center for Persistent Toxic Substances(IJRC-PTS) State Key Laboratory of Urban Water Resource and EnvironmentSchool of EnvironmentHarbin Institute of TechnologyHarbin150090China International Joint Research Center for Arctic Environment and Ecosystem(IJRC-AEE) Polar AcademyHarbin Institute of TechnologyHarbin150090China Institute of Ocean Sciences Department of Fisheries and OceansSidneyBCV8L 4B2Canada Centre for Earth Observation Science University of ManitobaWinnipegR3T 2N2Canada Air Quality Processes Research Section Environment and Climate Change CanadaTorontoOntarioCanada Canada Centre for Inland waters Environment and Climate Change CanadaBurlingtonOntarioCanada Faculty of Chemistry Biotechnology and Food Sciences(KBM)Norwegian University of Life Sciences(NMBU)NOe1433 AsNorway Institute of Natural Sciences North-Eastern Federal UniversityRussia IJRC-PTS-NA TorontoOntarioM2N 6X9Canada

The historical annual loading to,removal from,and cumulative burden in the Arctic Ocean for β-hexachlorocyclohexane(β-HCH),an isomer comprising 5e12%of technical HCH,is investigated using a mass balance box model from 1945 to *** the 76 years,loading occurred predominantly through ocean currents and river inflow(83%)and only a small portion via atmospheric transport(16%).β-HCH started to accumulate in the Arctic Ocean in the late 1940s,reached a peak of 810 t in 1986,and decreased to 87 t in 2020,when its concentrations in the Arctic water and air were~30 ng m^(-3)and~0.02 pg m^(-3),*** though β-HCH and α-HCH(60e70%of technical HCH)are both the isomers of HCHs with almost identical temporal and spatial emission patterns,these two chemicals have shown different major pathways entering the *** from α-HCH with the long-range atmospheric transport(LRAT)as its major transport pathway,β-HCH reached the Arctic mainly through long-range oceanic transport(LROT).The much higher tendency of β-HCH to partition into the water,mainly due to its much lower Henry's Law Constant than α-HCH,produced an exceptionally strong pathway divergence with β-HCH favoring slow transport in water and α-HCH favoring rapid transport in *** concentration and burden of β-HCH in the Arctic Ocean are also predicted for the year 2050 when only 4.4-5.3 t will remain in the Arctic Ocean under the influence of climate change.

关键词： β-Hexachlorocyclohexane Arctic Ocean Mass balance model Budget Air-water exchange

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Grow-light smart monitoring system leveraging lightweight deep learning for plant disease classification

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Artificial Intelligence in Agriculture 2024年第2期12卷 44-56页

作者： william macdonald Yuksel Asli Sari Majid Pahlevani Department of Electrical&Computer Engineering Queen's UniversityKingstonON K7L 3N6Canada The Robert M.Buchan Department of Mining Queen's UniversityKingstonON K7L 3N6Canada

This work focuses on a novel lightweight machine learning approach to the task of plant disease classification,posing as a core component of a larger grow-light smart monitoring *** the extent of our knowledge,this work is the first to implement lightweight convolutional neural network architectures leveraging down-scaled versions of inception blocks,residual connections,and dense residual connections applied without pre-training to the PlantVillage *** novel contributions of this work include the proposal of a smart monitor-ing framework outline;responsible for detection and classification of ailments via the devised lightweight net-works as well as interfacing with LED grow-light fixtures to optimize environmental parameters and lighting control for the growth of plants in a greenhouse *** adaptation of dense residual connections achieved the best balance of minimizing model parameters and maximizing performance metrics with accuracy,precision,recall,and F1-scores of 96.75%,97.62%,97.59%,and 97.58%respectively,while consisting of only 228,479 model *** results are further compared against various full-scale state-of-the-art model architectures trained on the PlantVillage dataset,of which the proposed down-scaled lightweight models were capable of performing equally to,if not better than many large-scale counterparts with drastically less com-putational requirements.

关键词： Plant disease classification Smart monitoring Deep learning Residual connections Inception Dense residual connections

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Nearest Neighbor Sampling of Point Sets Using Rays

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1131-1174页

作者： Liangchen Liu Louis Ly Colin B.macdonald Richard Tsai Department of Mathematics The University of Texas at Austin2515 SpeedwayAustinTX 78712USA Oden Institute for Computational Engineering and Sciences The University of Texas at Austin201 E24th StAustinTX 78712USA Department of Mathematics University of British Columbia1984 Mathematics RdVancouverBCV6T1Z2Canada

we propose a new framework for the sampling,compression,and analysis of distributions of point sets and other geometric objects embedded in Euclidean *** approach involves constructing a tensor called the RaySense sketch,which captures nearest neighbors from the underlying geometry of points along a set of *** explore various operations that can be performed on the RaySense sketch,leading to different properties and potential *** information about the data set can be extracted from the sketch,independent of the ray *** integrals on point sets can be efficiently computed using the *** also present several examples illustrating applications of the proposed strategy in practical scenarios.

关键词： Point clouds Sampling Classification Registration Deep learning Voronoi cell analysis

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Development of an experimental method for well-controlled blast induced traumatic limb fracture in rats

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Defence Technology（防务技术） 2024年第4期34卷 168-176页

作者： Luyang Xu Xiancheng Yu Clement DFavier Ibidumo Igah Thuy-Tien Nguyen warren macdonald Anthony MJ.Bull Centre for Blast Injury Studies Imperial College LondonLondonUnited Kingdom Department of Bioengineering Imperial College LondonLondonUnited Kingdom Dyson School of Design Engineering Imperial College LondonLondonUnited Kingdom Department of Trauma and Orthopaedics Royal Free London National Health Service Foundation TrustLondonUnited Kingdom

Heterotopic ossification(HO)is a consequence of traumatic bone and tissue damage,which occurs in 65%of military casualties with blast-associated ***,the mechanisms behind blast-induced HO remain *** models are used to study blast-induced HO,but developing such models is challenging,particularly in how to use a pure blast wave(primary blast)to induce limb fracture that then requires an *** studies,including our recent study,have developed platforms to induce limb fractures in rats with blast loading or a mixture of blast and impact ***,these models are limited by the survivability of the animal and repeatability of the *** this study,we developed an improved platform,aiming to improve the animal's survivability and injury repeatability as well as focusing on primary blast *** platform exposed only one limb of the rat to a blast wave while providing proper protection to the rest of the rat's *** obtained very consistent fracture outcome in the tibia(location and pattern)in cadaveric rats with a large range of size and ***,the rats did not obviously move during the test,where movement is a potential cause of uncontrolled *** further conducted parametric studies by varying the features of the design of the *** factors,such as how the limb is fixed and how the cavity through which the limb is placed is sealed,significantly affect the resulting *** platform and test setups enable well-controlled limb fracture induced directly by pure blast wave,which is the fundamental step towards a complete in vivo animal model for blast-induced HO induced by primary blast alone,excluding secondary and tertiary blast *** addition,the platform design and the findings presented here,particularly regarding the proper protection of the animal,have implications for future studies investigating localized blast injuries,such as blast induced brain and lung injuries.

关键词： Blast injury Biomechanics Heterotopic ossification Limb fracture Blast wave Animal model

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Microglial dysfunction and genetic risk for neurodegenerative disease

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Neural Regeneration Research 2025年第5期20卷 1401-1402页

作者： Debra S.macdonald Jay Penney Department of Biomedical Sciences AVCUniversity of Prince Edward IslandCharlottetownPECanada

Neurodegenerative disorders such as Alzheimer's and Parkinson's diseases a re increasing in prevalence as world populations *** tremendous progress has been made,our understanding of the mechanisms that underlie the development of these diseases remains far from com *** troubling,despite the growing emotional and financial toll being to ken by neurodegenerative disorders,existing treatment options are limited almost exclusively to those that help manage symptoms but that lack the ability to alter the progression of the disease(Liu et al.,2022).

关键词： degenerative diseases

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紫外线辐射和污染相关胁迫因子对北极淡水生态系统的影响

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AMBIO－人类环境杂志 2006年第7期35卷 384-396页

作者： Frederick J.wrona Terry D.Prowse James D.Reist John E.Hobbie Lucie M.J.Lévesque robie w.macdonald warwick F.Vincent 陈欣然 National water Research Institute of Environment Canada Water Science and Technology Directoratec/o Department of GeographyUniversity of Victoria water and Climate Impacts Research Centre National Water Research Institute of Environment CanadaDepartment of GeographyUniversity of Victoria Fisheries and Oceans Canada 501 University Crescent Marine Biological Laboratory The Ecosystems Center National Hydrology Research Centre Environment Canada Dépt de biologie & Centre d'étudesnordiques Université Laval

气候变化很可能作为一种多重胁迫因子,对水生生态系统造成累积的和/或协同的影响。预测的温度上升以及由此带来的降水季节性特征的改变将会增加污染物流入水生生态系统的量,并且会独自提高水生生物体对污染物暴露和影响的易感性。对生... 详细信息

气候变化很可能作为一种多重胁迫因子,对水生生态系统造成累积的和/或协同的影响。预测的温度上升以及由此带来的降水季节性特征的改变将会增加污染物流入水生生态系统的量,并且会独自提高水生生物体对污染物暴露和影响的易感性。对生物区系造成的结果在多数情况下是加和的(累积的)或倍增的(协同的),其总的结果必然是污染物负荷加重,生物放大作用(指有毒化学物质在食物链各环节中的毒性渐进)加强。同温层中臭氧和紫外线辐射季节性特征的变化也会对水生生态系统的结构和功能产生累加或协同的影响。与预测的同温层臭氧量减少这一原因相比,冰层覆盖度的降低可能对水下紫外线暴露产生更为重大的影响。紫外线辐射水平的大幅升高会导致对生物体的损伤增强(生物分子学、细胞学和生理学上的损害,以及物种组成的变化),而生物区系分配用于抵抗紫外线伤害的能量和资源也会增加,有可能使营养水平上的生产力降低。通过光化学途径,元素的通量将会增加。

关键词：紫外线辐射淡水生态系统胁迫因子污染物水生生态系统季节性特征北极有毒化学物质

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Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8页

作者： wéi wú Zhihui Luo Dao-Xin Yao Meng wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: while the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. we propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo

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Modified Atmospheric Packaging and Its Effect on Postharvest Cannabis Quality

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American Journal of Plant Sciences 2024年第3期15卷 222-234页

作者： Luke L. MacLaughlin Mason T. macdonald Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Halifax NS Canada

Cannabis sativa L. is used as fiber, food, and medicine in several countries. Though it is illegal for recreational use in most of the world, there are some countries that have legalized production and sale. There is a lot of research on production of cannabis, but less so on storage technologies. Cannabis contains several high value compounds, such as cannabinoids and terpenoids, that are susceptible to degradation via light, temperature, and oxygen. Several studies have explored temperature and light, and industry has adjusted accordingly. However, less is known about oxygen-induced degradation. Biochemical studies have demonstrated oxidative degradation of high value compounds, and many producers use some form of modified atmospheric packaging (MAP) for storage. However, the efficacy of MAP is unclear. The objective of this paper is to review our current understanding of MAP in postharvest cannabis storage and identify avenues where additional research is needed.

关键词： Cannabinoids Cannabis sativa Marijuana Nitrogen Packaging Oxidation Postharvest Terpenoids THC

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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

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