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corundum formation by metasomatic reactions in Archean metapelite,SW Greenland:Exploration vectors for ruby deposits within high-grade greenstone belts

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Geoscience Frontiers 2018年第3期9卷 727-749页

作者： chris yakymchuk Kristoffer Szilas Earth and Environmental Sciences University of Waterloo200 University Ave WestWaterlooOntario N2L 3G1Canada Geological Survey of Denmark and Greenland(GEUS) Oter Voldgade 101350 Copenhagen KDenmark

corundum(ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic craton of Greenland. Here we present two case studies for such occurrences:(1) Maniitsoq region(Kangerdluarssuk), where kyanite paragneiss hosts ruby corundum, and(2)Nuuk region(Stor?), where sillimanite gneiss hosts ruby corundum. At both occurrences, ultramafic rocks(amphibole-peridotite) are in direct contact with the ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the ruby-bearing rocks is consistent with significant depletion of SiO_2 in combination with addition of Al_2O_3, MgO, K_2O,Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO_2. The juxtaposition of relatively silica-and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO_2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al_2O_3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal *** three main exploration vectors for corundum within Archean greenstone belts are:(1) amphiboliteto granulite-facies metamorphic conditions,(2) the juxtaposition of ultramafic rocks and aluminous metapelite, and(3) mica-rich reactions zones at their interface.

关键词： Ultramafic rocks Kyanite Sillimanite Metasomatism Pseudosection Desilicification

Garnet fractionation,progressive melt loss and bulk composition variations in anatectic metabasites:complications for interpreting the geodynamic significance of TTGs

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Geoscience Frontiers 2020年第3期11卷 745-763页

作者： Jillian Kendrick chris yakymchuk Department of Earth and Environmental Sciences University of WaterlooWaterlooOntarioN2L 3G1Canada

Tonalite-trondhjemite-granodiorite(TTG) suites constitute a large proportion of the Archean geological record;however,the geodynamic processes that generated them,and Archean continental crust in general,remain a subject of *** concentrations and ratios of Sr,Y,La,Yb,Nb,and Ta in TTGs are commonly used to determine the depth of melting of their metabasic *** trace element composition of melt produced by metabasic source rocks during anatexis is strongly affected by the presence and abundance of pressure-sensitive minerals,such as plagioclase(Sr-bearing),garnet(Y-and HREE-bearing),and rutile(Nb-and Ta-bearing).Elevated Sr/Y and La/Yb ratios and low concentrations of Nb and Ta in TTGs are generally considered to indicate melting at high pressures(≥2.0 GPa).The depth of melting is a key factor in determining the origin of TTGs as this provides critical information on the tectonic setting of their *** use phase equilibrium and trace element modelling to explore the effects of three potential influences on TTG trace element compositions:fractionation of trace elements into peritectic garnet cores,progressive melt loss from the source,and source bulk *** model three different compositions of Archean basalts along thermal gradients of 500℃/GPa,750℃/GPa,and 1000℃/*** models produce maj or and trace element melt compositions that are generally consistent with measured compositions of *** Sr/Y,La/Yb,Nb,and Ta exhibit pressure-dependent behaviour,other factors also affect these *** fractionation causes Sr/Y and La/Yb to reach much greater values and in this scenario,the values also increase with increasing *** bulk composition has an effect in all scenarios and most strongly influences La/Yb,Nb,and ***,these results show that Sr/Y,La/Yb,Nb,and Ta can reach values generally considered to be indicative of high pressure melting at a range of P-T conditions including P ce ele

关键词： Archean Anatexis Trace element Phase equilibrium modelling Tectonics

Status and prospects for symmetric organic redox flow batteries

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Journal of Energy chemistry 2025年第1期100卷 125-143页

作者： Md Al Raihan c.Adam Dyker Department of chemistry University of New Brunswick

As environmental concerns from fossil fuel consumption intensify, large-scale energy storage becomes imperative for the integration of renewable sources like wind, hydro, and solar with the electrical *** flow batteries, particularly those employing organic molecules, are positioned as a key technology for this purpose. This review explores the growing field of symmetric organic redox flow batteries(ORFBs) within this context. Unlike traditional asymmetric designs based on unique active materials for each electrode, symmetric ORFBs involve a single bipolar species for both electrodes. This review highlights the benefits of a symmetric design, and categorizes five distinct classes of organic bipolar molecules used in both aqueous and non-aqueous solvents. By providing a comprehensive overview of their cell cycling and performance characteristics, the strengths and weaknesses of the diverse categories of bipolar molecules are highlighted for both solvent systems, as are opportunities for future development. This should guide new research directions and advance the development of practical symmetric ORFBs.

关键词： Redox flow battery Symmetric battery Organic battery Aqueous electrolyte Non-aqueous electrolyte

Acquired sensorineural hearing loss,oxidative stress,and microRNAs

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Neural Regeneration Research 2025年第9期20卷 2513-2519页

作者： Desmond A.Nunez Ru c.Guo Division of Otolaryngology–Head&Neck Surgery Department of SurgeryFaculty of MedicineThe University of British ColumbiaVancouverBCCanada Division of Otolaryngology–Head&Neck Surgery Gordon&Leslie Diamond Health Care CentreVancouver General HospitalVancouverBCCanada Faculty of Medicine–The University of British columbia VancouverBCCanada

Hearing loss is the third leading cause of human ***-related hearing loss,one type of acquired sensorineural hearing loss,is largely responsible for this escalating global health ***-induced,ototoxic,and idiopathic sudden sensorineural are other less common types of acquired hearing *** etiology of these conditions is complex and multi-fa ctorial involving an interplay of genetic and environmental *** stress has recently been proposed as a likely linking cause in most types of acquired sensorineural hearing *** non-coding RNA sequences known as microRNAs(miRNAs)have increasingly been shown to play a role in cellular hypoxia and oxidative stress responses including promoting an apoptotic *** hair cell death is a central histopathological finding in sensorineural hearing *** these cells do not regenerate in humans,it underlies the irreversibility of human age-related hearing *** EMBASE,Ovid MEDLINE,Web of Science core collection,and *** databases over the period August 1,2018 to July 31,2023 were searched with"hearing loss,""hypoxamiRs,""hypoxia,""microRNAs,""ischemia,"and"oxidative stress"text words for English language primary study publications or registered clinical *** red clinical trials known to the senior author we re also assessed.A total of 222studies were thus *** excluding duplicates,editorials,retra ctions,secondary research studies,and non-English language articles,39 primary studies and clinical trials underwent full-text *** resulted in 11 animal,in vitro,and/or human subject journal articles and 8 registered clinical trial database entries which form the basis of this narrative *** miR-34a and miR-29b levels increase with age in *** miRNAs were demonstrated in human neuroblastoma and murine cochlear cell lines to target Sirtuin 1/peroxisome proliferato r-activated receptor gamma coactivator-1-alpha(SIRT1/P Gc-1α),SIRT

关键词： hearing loss hypoxia microRNAs oxidative stress sensorineural

Multiple sclerosis is at a checkpoint: advancing the program

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Neural Regeneration Research 2025年第3期20卷 811-812页

作者： Brandon c.Smith Jessica L.Williams Department of Neurosciences Lerner Research InstituteCleveland ClinicClevelandOHUSA Department of Biological Geologicaland Environmental SciencesCleveland State UniversityClevelandOHUSA

Multiple sclerosis(MS) is a chronic inflammatory and demyelinating disease of the central nervous system(cNS). Patients with MS experience sensory and motor function loss due to myelin and/or axon damage perpetuated b... 详细信息

关键词： Hauser sclerosis damage

A greenstone belt in southeast Tibet:An accreted middle–late Permian oceanic plateau

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Geoscience Frontiers 2023年第3期14卷 117-130页

作者： Bin Wang chao-Ming Xie chris yakymchuk Yong-sheng Dong Yu-hang Song Meng-long Duan college of Earth Sciences Jilin UniversityChangchun 130061China Key Laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Natural Resources of ChinaChangchun 130061China Research center for Tibetan Plateau Jilin UniversityChangchun 130061China Department of Earth and Environmental Sciences University of WaterlooWaterlooOntario N2L 3G1Canada

Studies of accreted oceanic plateau sections provide crucial information on their structures,compositions,and *** investigate the petrogenesis of ultramafic–mafic rocks in the Tangjia–Sumdo greenstone belt of southeast Tibet using petrography,whole-rock geochemistry,and U-Pb zircon *** rocks are divided into four groups based on geochemical characteristics that include depleted and tholeiitic mafic rocks,transitional mafic rocks,enriched and alkaline mafic rocks,and picritic ultramafic *** and tholeiitic mafic rocks have the oldest crystallization ages(-272 Ma),followed by picritic ultramafic rocks(-270 Ma),transitional mafic rocks(267–254 Ma),and enriched and alkaline mafic rocks(252–250 Ma).Hafnium and neodymium isotope ratios of depleted and tholeiitic mafic rocks(ε_(Hf)(t)=+13.1–+16.9;ε_(Nd)(t)=+6.9–+7.1),transitional mafic rocks(ε_(Hf)(t)=+1.8–+16.9;ε_(Nd)(t)=+0.8–+5.5),enriched and alkaline mafic rocks(ε_(Hf)(t)=+0.5–+5.4;ε_(Nd)(t)=1.5 to+1.9)and picritic ultramafic rocks(ε_(Hf)(t)=+14.9–+17.2;ε_(Nd)(t)=+7.8–+9.0)are similar to those of N-MORB,E-MORB,OIB and depleted-type picritic mafic rocks in other oceanic plateaus,*** geochemical characteristics of the depleted and tholeiitic mafic rocks suggest that they formed by partial melting of depleted spinel lherzolite in a mid-ocean ridge setting,whereas the picritic ultramafic rocks suggest a high degree of partial melting of depleted lherzolite in a hot mantle plume *** transitional mafic rocks formed by partial melting of moderately enriched garnet *** youngest rocks(enriched and alkaline mafic rocks)formed by partial melting of a more enriched garnet lherzolite(compared to transitional mafic rocks)at relatively low *** propose that the depleted and tholeiitic mafic rocks represent normal oceanic crust of the Sumdo Paleo-Tethys Ocean and the transitional mafic rocks,enriched and alkaline mafic rocks and picritic ultramafic rocks are the

关键词： Oceanic plateau Mantle plume Paleo-Tethys Tibet Greenstone belts

Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

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Nano-Micro Letters 2025年第1期17卷 293-309页

作者： Kiran A.Nirmal Tukaram D.Dongale Atul c.Khot chenjie Yao Nahyun Kim Tae Geun Kim School of Electrical Engineering Korea UniversityAnam‑ro 145Seongbuk‑guSeoulRepublic of Korea computational Electronics and Nanoscience Research Laboratory School of Nanoscience and BiotechnologyShivaji UniversityKolhapur 416004India

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic ***,they are crucial for applications in the fields of energy,display,healthcare,and soft *** meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical *** this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted *** this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical *** also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device *** addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

关键词： Self-cracking template Vanadium-doped indium zinc oxide mesh Organic solar cells Organic light-emitting diodes Flexible transparent memory

Machine learning empowers efficient design of ternary organic solar cells with PM6 donor

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Journal of Energy chemistry 2025年第1期100卷 337-347页

作者： Kiran A.Nirmal Tukaram D.Dongale Santosh S.Sutar Atul c.Khot Tae Geun Kim School of Electrical Engineering Korea University computational Electronics and Nanoscience Research Laboratory School of Nanoscience and Biotechnology Shivaji University Yashwantrao chavan School of Rural Development Shivaji University

Organic solar cells(OScs) hold great potential as a photovoltaic technology for practical ***, the traditional experimental trial-and-error method for designing and engineering OScs can be complex, expensive, and time-consuming. Machine learning(ML) techniques enable the proficient extraction of information from datasets, allowing the development of realistic models that are capable of predicting the efficacy of materials with commendable accuracy. The PM6 donor has great potential for high-performance OScs. However, it is crucial for the rational design of a ternary blend to accurately forecast the power conversion efficiency(PcE) of ternary OScs(TOScs) based on a PM6 ***, we collected the device parameters of PM6-based TOScs and evaluated the feature importance of their molecule descriptors to develop predictive models. In this study, we used five different ML algorithms for analysis and prediction. For the analysis, the classification and regression tree provided different rules, heuristics, and patterns from the heterogeneous dataset. The random forest algorithm outperforms other prediction ML algorithms in predicting the output performance of PM6-based TOScs. Finally, we validated the ML outcomes by fabricating PM6-based TOScs. Our study presents a rapid strategy for assessing a high PcE while elucidating the substantial influence of diverse descriptors.

关键词： Random forests

Some Results of Direct FR Technology Applied to Study Methane Seepage Areas in the Arctic Region

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Advances in Geological and Geotechnical Engineering Research 2023年第3期5卷 25-38页

作者： Mykola yakymchuk Ignat Korchagin Valery Soloviev Institute of Applied Problems of Ecology Geophysics and GeochemistryKyiv03126Ukraine Institute of Geophysics NAS of UkraineKyiv03680Ukraine

The experimental study of the seepage processes’sources formation in structures of the Arctic Region was carried out using modified methods of frequency-resonance(FR)processing and decoding of satellite images and photographs with the vertical scanning of the *** newly obtained results show that the intensity and dynamics of the methane seeps and pockmarks fields’formation depend on active deep degassing processes in the continental margin *** use of direct FR-sounding technologies allows for determining the probable origin and depth of geological sources of gas migration at marginal migration centers in Greenland,and Norwegian and Barents *** results confirm the crust-mantle gas fluids’influence on the nature and degassing processes features in the scan points of polar marginal *** data are important arguments in favor of the“volcanic model”of various structural elements formation in this and other *** FR technologies data also showed a possibility of seeps use as shallow and deep hydrocarbon field indicators in gas emission *** independent data can be used in compiling models of the deep lithosphere structure and possible mechanisms of abiogenetic hydrocarbon formation in Arctic margin *** authors suppose that hydrocarbons through deep channels migrate(from 57 km deep)to the upper crustal horizons where their fields can *** this migration,gas seeps and pockmarks are formed on the sea bottom and part of the gas can migrate into the *** show that basaltic volcanoes in Greenland scan points can be the real channels through which hydrogen migrates to the upper crustal horizons and further into the *** gas migration in Arctic seepage areas can be an important factor in the global climate change processes.

关键词： FR mobile technologies Active hydrocarbon seepage Greenland Spitsbergen Polar Arctic