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A Paleozoic mercury mineralisation event in South China:In situ U-Pb dating and chemical compositions of calcite from the Jianyan Hg deposit

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Science China Earth Sciences 2023年第8期66卷 1877-1891页

作者： Kai LUO Jiaxi ZHOU alexandre CUgERONE Meifu ZHOU Yuexing FENg Zhongguo JIN Jianxin ZHAO Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province School of Earth SciencesYunnan UniversityKunming 650500China School of Earth and Environmental Sciences The University of QueenslandBrisbane QLD 4072Australia State Key Laboratory of Ore Deposit geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Department of Earth Sciences University of GenevaGeneva 1205Switzerland Southern Marine Science and Engineering guangdong Laboratory Zhuhai 519000China Non-Ferrous Metals and Nuclear Industry geological Exploration Bureau of guizhou Guiyang 550005China

The ages of hydrothermal Hg deposits are difficult to constrain because of the lack of suitable minerals for dating.The South China low-temperature metallogenic domain hosts numerous Hg deposits,including the Jianyan Hg deposit that is composed mainly of cinnabar and calcite.There are two stages of calcite in the deposit:syn-ore calcite(Cal-Ⅰ)and post-ore/barren calcite(Cal-Ⅱ).Cal-Ⅰis mainly euhedral-subhedral and fine-grained,has homogeneous grey luminescence,and is associated with cinnabar.Subhedral-anhedral Cal-Ⅱcrosscuts Cal-Ⅰand is relatively coarse-grained.The syn-ore Cal-Ⅰhas high U contents(0.1–1.3 ppm)and U/Pb ratios(up to 4.2),and is thus suitable for U-Pb dating.Using a laser ablation-inductively coupled plasma-mass spectrometer equipped with ion counters,we obtained a U-Pb age of 426.3±5.7 Ma(MSWD=1.5)for CalI.This age is interpreted to represent the timing of Hg mineralisation at Jianyan and is similar to ages of 440–400 Ma reported for many carbonate-hosted Pb-Zn and Ba-F deposits in South China.Based on the present results in combination with existing geochemical and geochronological data,we infer that these deposits belong to a Paleozoic Hg-Pb-Zn-Ba-F mineralisation system that was controlled by Caledonian tectonism.

关键词： In situ calcite U-Pb dating Paleozoic Hg mineralisation Caledonian tectonism Jianyan Hg deposit South China

Astrometric calibration and source characterisation of the latest generation neuromorphic event-based cameras for space imaging

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Astrodynamics 2023年第4期7卷 415-443页

作者： Nicholas Owen Ralph alexandre Marcireau Saeed Afshar Nicholas Tothill Andre van Schaik gregory Cohen International Centre for Neuromorphic Systems MARCS Institute for BrainBehaviour and DevelopmentWestern Sydney UniversityKingswood 2747NSWAustralia

As an emerging approach to space situational awareness and space imaging,the practical use of an event-based camera(EBC)in space imaging for precise source analysis is still in its infancy.The nature of event-based space imaging and data collection needs to be further explored to develop more effective event-based space imaging systems and advance the capabilities of event-based tracking systems with improved target measurement models.Moreover,for event measurements to be meaningful,a framework must be investigated for EBC calibration to project events from pixel array coordinates in the image plane to coordinates in a target resident space object’s reference frame.In this paper,the traditional techniques of conventional astronomy are reconsidered to properly utilise the EBC for space imaging and space situational awareness.This paper presents the techniques and systems used for calibrating an EBC for reliable and accurate measurement acquisition.These techniques are vital in building event-based space imaging systems capable of real-world space situational awareness tasks.By calibrating sources detected using the EBC,the spatiotemporal characteristics of detected sources or“event sources”can be related to the photometric characteristics of the underlying astrophysical objects.Finally,these characteristics are analysed to establish a foundation for principled processing and observing techniques which appropriately exploit the capabilities of the EBC.

关键词： neuromorphic event-based camera(EBC) space imaging space situational awareness(SSA) astronomy

A comparison of three surface roughness characterization techniques:photogrammetry,pin profiler,and smartphone-based LiDAR

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International Journal of Digital Earth 2022年第1期15卷 2422-2439页

作者： Zohreh Alijani Julien Meloche Alexander McLaren John Lindsay alexandre Roy Aaron Berg Department of geography Environment and GeomaticsUniversity of GuelphGuelphCanada Département de géomatique Appliquée Université de SherbrookeSherbrookeCanada Département des Sciences de l’Environment Université du Québec à Trois-RivièresTrois-RivièresCanada

Surface roughness plays an important role in microwave remote sensing.In the agricultural domain,surface roughness is crucial for soil moisture retrieval methods that use electromagnetic surface scattering or microwave radiative transfer models.Therefore,improved characterization of Soil Surface Roughness(SSR)is of considerable importance.In this study,three approaches,including a standard pin profiler,a LiDAR point cloud generated from an iPhone 12 Pro,and a Structure from Motion(SfM)photogrammetric point cloud,were applied over 24 surface profiles with different roughness variations to measure surface roughness.The objective of this study was to evaluate the capability of smartphone-based LiDAR technology to measure surface roughness parameters and compare the results of this technique with the more common approaches.Results showed that the iPhone LiDAR technology,when point cloud data is captured in a fine-resolution mode,has a significant correlation with SfM photogrammetry(R2=0.70)and a relatively close agreement with pin profiler(R2=0.60).However,this accuracy tends to be greater for random surfaces and rough profiles with row structure orientations.The results of this study confirm that smartphone-based LiDAR can be used as a cost-effective,fast,and time-efficient alternative tool for measuring surface roughness,especially for rough,wide,and inaccessible areas.

关键词： LiDAR surface roughness structure from motion iPhone pin profiler

A Novel Approach to Measuring Spatiotemporal Changes in Social Vulnerability at the Local Level in Portugal

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International Journal of Disaster Risk Science 2022年第6期13卷 842-861页

作者： Pedro Pinto Santos JoséLuís Zêzere Susana Pereira Jorge Rocha alexandre Oliveira Tavares Centre for geographical Studies Institute of Geography and Spatial PlanningTERRAUniversity of Lisbon(CEG-IGOT-ULisboa)1600-276 LisboaLAPortugal Centre for Social Studies Earth Science DepartmentScience and Technology FacultyUniversity of Coimbra(CES/DCT-FCT-UCoimbra)3000-995 CoimbraPortugal

Social vulnerability,as one of the risk components,partially explains the magnitude of the impacts observed after a disaster.In this study,a spatiotemporally comparable assessment of social vulnerability and its drivers was conducted in Portugal,at the civil parish level,for three census frames.The first challenging step consisted of the selection of meaningful and consistent variables over time.Data were normalized using the Adjusted Mazziotta-Pareto Index(AMPI)to obtain comparable adimensional-normalized values.A joint principal component analysis(PCA)was applied,resulting in a robust set of variables,interpretable from the point of view of their self-grouping around vulnerability drivers.A separate PCA for each census was also conducted,which proved to be useful in analyzing changes in the composition and type of drivers,although only the joint PCA allows the monitoring of spatiotemporal changes in social vulnerability scores and drivers from 1991 to 2011.A general improvement in social vulnerability was observed for Portugal.The two main drivers are the economic condition(PC1),and aging and depopulation(PC2).The remaining drivers highlighted are uprooting and internal mobility,and daily commuting.Census data proved their value in the territorial,social,and demographic characterization of the country,to support medium-and long-term disaster risk reduction measures.

关键词： AMPI normalization Portugal Social vulnerability Spatiotemporal changes

Eosinophils in the gastrointestinal tract and their role in the pathogenesis of major colorectal disorders

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World Journal of gastroenterology 2019年第27期25卷 3503-3526页

作者： alexandre Loktionov DiagNodus Ltd Babraham Research Campus

Eosinophils are currently regarded as versatile mobile cells controlling and regulating multiple biological pathways and responses in health and disease.These cells store in their specific granules numerous biologically active substances(cytotoxic cationic proteins, cytokines, growth factors, chemokines,enzymes) ready for rapid release. The human gut is the main destination of eosinophils that are produced and matured in the bone marrow and then transferred to target tissues through the circulation. In health the most important functions of gut-residing eosinophils comprise their participation in the maintenance of the protective mucosal barrier and interactions with other immune cells in providing immunity to microbiota of the gut lumen. Eosinophils are closely involved in the development of inflammatory bowel disease(IBD),when their cytotoxic granule proteins cause damage to host tissues. However,their roles in Crohn’s disease and ulcerative colitis appear to follow different immune response patterns. Eosinophils in IBD are especially important in altering the structure and protective functions of the mucosal barrier and modulating massive neutrophil influx to the lamina propria followed by transepithelial migration to colorectal mucus. IBD-associated inflammatory process involving eosinophils then appears to expand to the mucus overlaying the internal gut surface. The author hypothesises that immune responses within colorectal mucus as well as ETosis exerted by both neutrophils and eosinophils on the both sides of the colonic epithelial barrier act as additional pathogenetic factors in IBD. Literature analysis also shows an association between elevated eosinophil levels and better colorectal cancer(CRC) prognosis, but mechanisms behind this effect remain to be elucidated. In conclusion, the author emphasises the importance of investigating colorectal mucus in IBD and CRC patients as a previously unexplored milieu of disease-related inflammatory responses.

关键词： Eosinophils Eosinophilopoiesis gut lamina propria Colorectal mucus Normal human small intestine Normal human colon Inflammatory bowel disease Crohn’s disease Ulcerative colitis Colorectal cancer

Unraveling and optimizing the metal-metal oxide synergistic effect in a highly active Co_(x)(CoO)_(1–x) catalyst for CO_(2) hydrogenation

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Journal of Energy Chemistry 2021年第2期30卷 241-250,I0009页

作者： Kun Zhao Marco Calizzi Emanuele Moioli Mo Li alexandre Borsay Loris Lombardo Robin Mutschler Wen Luo Andreas Zuttel Laboratory of Materials for Renewable Energy Institute of Chemical Sciences and Engineeringtcole Polytechnique Federale de Lausanne(EPFL)1951 SionSwitzerland Swiss Federal Laboratories for Materials Science and Technology(EMPA) 8600 DiibendorfSwitzerland

The relation between catalytic reactivities and metal/metal oxide ratios, as well as the functions of the metal and the metal oxides were investigated in the CO_2 hydrogenation reaction over highly active Co_x(CoO)_(1–x)catalysts in operando. The catalytic reactivity of the samples in the CO_2 methanation improves with the increased Co O concentration. Strikingly, the sample with the highest concentration of CoO, i.e., Co_(0.2)(CoO)_(0.8), shows activity at temperatures lower than 200 °C where the other samples with less CoO are inactive. The origins of this improvement are the increased amount and moderate binding of adsorbed CO_2 on CoO sites. The derivative adsorption species are found to be intermediates of the CH4 formation. The metallic Co functions as the electronically catalytic site which provides electrons for the hydrogenation steps. As a result, an abundant amount of CoO combined with Co is the optimal composition of the catalyst for achieving the highest reactivity for CO_2 hydrogenation.

关键词： Cobalt and cobalt oxide Reactivity CO_(2)hydrogenation Active site Adsorption Activation energy

Biomarkers for detecting colorectal cancer non-invasively: DNA,RNA or proteins?

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World Journal of gastrointestinal Oncology 2020年第2期12卷 124-148页

作者： alexandre Loktionov Diag Nodus Ltd Babraham Research Campus

Colorectal cancer(CRC)is a global problem affecting millions of people worldwide.This disease is unique because of its slow progress that makes it preventable and often curable.CRC symptoms usually emerge only at advanced stages of the disease,consequently its early detection can be achieved only through active population screening,which markedly reduces mortality due to this cancer.CRC screening tests that employ non-invasively detectable biomarkers are currently being actively developed and,in most cases,samples of either stool or blood are used.However,alternative biological substances that can be collected non-invasively(colorectal mucus,urine,saliva,exhaled air)have now emerged as new sources of diagnostic biomarkers.The main categories of currently explored CRC biomarkers are:(1)Proteins(comprising widely used haemoglobin);(2)DNA(including mutations and methylation markers);(3)RNA(in particular microRNAs);(4)Low molecular weight metabolites(comprising volatile organic compounds)detectable by metabolomic techniques;and(5)Shifts in gut microbiome composition.Numerous tests for early CRC detection employing such non-invasive biomarkers have been proposed and clinically studied.While some of these studies generated promising early results,very few of the proposed tests have been transformed into clinically validated diagnostic/screening techniques.Such DNA-based tests as Food and Drug Administration-approved multitarget stool test(marketed as Cologuard®)or blood test for methylated septin 9(marketed as Epi proColon®2.0 CE)show good diagnostic performance but remain too expensive and technically complex to become effective CRC screening tools.It can be concluded that,despite its deficiencies,the protein(haemoglobin)detection-based faecal immunochemical test(FIT)today presents the most cost-effective option for non-invasive CRC screening.The combination of non-invasive FIT and confirmatory invasive colonoscopy is the current strategy of choice for CRC screening.However,continuing intense research in the area prom

关键词： Colorectal cancer screening Biomarkers Non-invasive testing Stool Colorectal mucus Blood

Neural regeneration research model to be explored:SH-SY5Y human neuroblastoma cells

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Neural Regeneration Research 2023年第6期18卷 1265-1266页

作者： Lavynia Ferreira Hoffmann alexandre Martins Fernanda Majolo Verônica Contini Stefan Laufer Márcia Inês goetiert graduate Program in Biotechnology University of Vale do Taquari(Univates)LajeadoRio Grande do SulBrazil graduate Program in Medical Sciences-PPgCM University of Vale do Taquari-UnivatesLajeado/RSBrazil Institute of Pharmacy Pharmaceutical/Medicinal Chemistry and Tübingen Center for Academic Drug Discovery-TÜCADDEberhard Karls University TübingenTübingenGermany

In neuroscience research,neuronal models are crucial tools for elucidating the molecular and cellular processes involved in the disorders of the nervous system.Facilitating easily and reproducibly executable studies,in vitro models,such as the SH-SY5Y cell line culture,help us explore the pathophysiological mechanisms of neurodegenerative diseases;they are also essential for the efficient screening of drugs for treating the diseases of the nervous system(Peng et al.,2021;Strother et al.,2021).

关键词： neuroblastoma diseases

Dynamical machine learning volumetric reconstruction of objects’ interiors from limited angular views

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Light(Science & Applications) 2021年第5期10卷 824-844页

作者： Iksung Kang alexandre goy george Barbastathis Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology77 Massachusetts AveCambridgeMAUSA Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Singapore-MIT Alliance for Research and Technology(SMART)Centre 1 Create WaySingapore 117543Singapore Omnisens SA Morges 1110Switzerland

Limited-angle tomography of an interior volume is a challenging, highly ill-posed problem with practical implications in medical and biological imaging, manufacturing, automation, and environmental and food security. Regularizing priors are necessary to reduce artifacts by improving the condition of such problems. Recently, it was shown that one effective way to learn the priors for strongly scattering yet highly structured 3D objects, e.g. layered and Manhattan, is by a static neural network [goy et al. Proc. Natl. Acad. Sci. 116, 19848–19856 (2019)]. Here, we present a radically different approach where the collection of raw images from multiple angles is viewed analogously to a dynamical system driven by the object-dependent forward scattering operator. The sequence index in the angle of illumination plays the role of discrete time in the dynamical system analogy. Thus, the imaging problem turns into a problem of nonlinear system identification, which also suggests dynamical learning as a better fit to regularize the reconstructions. We devised a Recurrent Neural Network (RNN) architecture with a novel Separable-Convolution gated Recurrent Unit (SC-gRU) as the fundamental building block. Through a comprehensive comparison of several quantitative metrics, we show that the dynamic method is suitable for a generic interior-volumetric reconstruction under a limited-angle scheme. We show that this approach accurately reconstructs volume interiors under two conditions: weak scattering, when the Radon transform approximation is applicable and the forward operator well defined;and strong scattering, which is nonlinear with respect to the 3D refractive index distribution and includes uncertainty in the forward operator.

关键词： interior dynamical angular