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The great catastrophe: causes of the permo-Triassic marine mass extinction

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National Science review 2024年第1期11卷 37-50页

作者： paul B.Wignall David p.g.Bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high temperatures.Other kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(rwhelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes including an earlier crisis which merits furthe

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Excellent photoluminescence and electrochemical properties of Sm^(3+) doped Ca_(2)MgSi_(2)O_(7) nanophosphor:Display and electrochemical sensor applications

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Journal of rare Earths 2024年第6期42卷 1046-1055,I0002页

作者： r.B.Basavaraj K.Sureshkumar D.p.Aarti M.B.Madhusudana reddy g.Nagaraju T.ramakrishnappa g.r.Navyashree K.r.Venkatesha Babu K.S.Hemalatha Department of physics BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry School of Applied SciencesREVA UniversityBangalore560064India Energy Materials researchLaboratory Department of ChemistrySiddaganga Institute of TechnologyTumakuru57203KarnatakaIndia School of physical Sciences REVA UniversityBangalore560057Indi Department of physics Govt.Science CollegeBengaluru560001India Department of physics Maharani Science College for WomenMaharani Cluster UniversityBengaluru560001India

A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirmed by the powder X-ray diffraction(pXrD)technique.pure single-phase tetragonal structure is observed from the pXrD results with no additional impurity peaks.The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DrS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the samples.Honeycomb-like structures are observed from the SEM results.The particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 nm.The interplanar distance is found to be 0.53 nm.photoluminescence properties were systematically studied in detail.The phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic emission.The emission peaks are centered at 558(^(4)g_(5/2)→^(6)H_(5/2)),607(^(4)g_(5/2)→^(6)H_(7/2))and 645 nm(^(4)g_(5/2)→^(6)H_(9/2)),respectively.Among the observed peaks the red emanation(^(4)g_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)g_(5/2)→^(6)H_(5/2))in the current investigation.The photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping content.The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism.The color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in detail.The optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange region.The average CCT value obtained is 3362 K.The average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm^(3+)ions th

关键词： green combustion photoluminescence Orange-red emission Color purity Sensors rare earths

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Severe acute respiratory syndrome-coronavirus-2(SArS-COV-2)infection of pneumocytes with vaccination and drug therapy:Mathematical analysis and optimal control

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International Journal of Biomathematics 2024年第2期17卷 299-334页

作者： r.Viriyapong p.Inkhao Department of Mathematics Faculty of Science Naresuan University Phitsanulok65000Thailand

We propose a mathematical model studying a within-host infection dynamics of SArSCoV-2 in pneumocytes.This model incorporates immune response,vaccination and antiviral drugs.The crucial properties of the model-the existence,positivity and boundary of solutions are established.Equilibrium points and the basic reproduction number are calculated.The stability of each equilibrium point is analyzed.Optimal control is applied to the model by adding three control variables:vaccination,treatment by Favipiravir and treatment by Molnupiravir.Numerical results show that each individual control could reduce SArS-CoV-2 infection in some aspects;however,with a combination of three controls,we obtain the best results in reducing SArS-CoV-2 infection.This study has emphasized the importance of prevention by vaccine and the antiviral treatments.

关键词： SArS-CoV-2 vaccination drug therapy immune response optimal control

radioisotope production using lasers:From basic science to applications

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Matter and radiation at Extremes 2024年第3期9卷 31-44页

作者： M.r.D.rodrigues A.Bonasera M.Scisciò J.A.pérez-Hernández M.Ehret F.Filippi p.L.Andreoli M.Huault H.Larreur D.Singappuli D.Molloy D.raffestin M.Alonzo g.g.rapisarda D.Lattuada g.L.guardo C.Verona Fe.Consoli g.petringa A.McNamee M.La Cognata S.palmerini T.Carriere M.Cipriani g.Di giorgio g.Cristofari r.De Angelis g.A.p.Cirrone D.Margarone L.giuffrida D.Batani p.Nicolai K.Batani r.Lera L.Volpe D.giulietti S.Agarwal M.Krupka S.Singh Fa.Consoli Cyclotron Institute Texas A&M UniversityCollege StationTexas 77840USA Laboratori Nazionali del Sud Istituto Nazionale di Fisica Nucleare(LNS-INFN)CataniaItaly ENEA Fusion and Technologies for Nuclear Safety and Security Department-CFrascatiItaly Centro de Láseres pulsados(clpu) VillamayorSpain Universidad de Salamanca SalamancaSpain Centre Lasers Intenses et Applications(CELIA) Universitéde BordeauxCNRSCEATalenceFrance HB11 Energy Holdings pty FreshwaterNew South WalesAustralia School of Mathematics and physics Queen’s University BelfastBelfastUnited Kingdom Dipartimento di Fisica e Astronomia“E.Majorana ”Università di CataniaCataniaItaly Facoltàdi Ingegneria e Architettura Universitàdegli Studi di Enna“Kore”EnnaItaly Dipartimento di Ingegneria Industriale Universitàdi Roma“Tor Vergata”RomaItaly Dipartimento di Fisica e geologia Universitàdegli Studi di PerugiaPerugiaItaly Istituto Nazionale di Fisica Nucleare Sezione di PerugiaPerugiaItaly ELI Beamlines Facility the Extreme Light Infrastructure ERICDolni BrezanyCzech Republic ETSIA Universidad Politécnica de MadridMadridSpain Dipartimento Fisica “E.Fermi”Universitàdi Pisa and INFNPisaItaly FZU–Institute of physics of Czech Academy of Sciences PragueCzech Republic Institute of plasma physics of Czech Academy of Sciences PragueCzech Republic

The discovery of chirped pulse amplification has led to great improvements in laser technology,enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers.protons with energies of tens of MeV can be accelerated using,for instance,target normal sheath acceleration and focused on secondary targets.Under such conditions,nuclear reactions can occur,with the production of radioisotopes suitable for medical application.The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators.In this paper,we study the production of^(67)Cu,^(63)Zn,^(18)F,and^(11)C,which are currently used in positron emission tomography and other applications.At the same time,we study the reactions^(10)B(p,α)^(7)Be and^(70)Zn(p,4n)^(67)ga to put further constraints on the proton distributions at different angles,as well as the reaction^(11)B(p,α)^(8)Be relevant for energy production.The experiment was performed at the 1 pW laser facility at VegaⅢin Salamanca,Spain.Angular distributions of radioisotopes in the forward(with respect to the laser direction)and backward directions were measured using a high purity germanium detector.Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera[Nucl.Instrum.Methods phys.res.,Sect.A 637,164–170(2011)].

关键词： purity estimates backward

reinforced tissue matrix to strengthen the abdominal wall following reversal of temporary ostomies or to treat incisional hernias

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World Journal of gastrointestinal Surgery 2024年第3期16卷 823-832页

作者： Spencer p Lake Corey r Deeken Amit K Agarwal Mechanical Engineering&Materials Science Washington University in St.LouisSt.LouisMO 63130United States Covalent Bio LLCSt.LouisMO 63025United States Department of Surgery McGovern Medical School at UTHealthHoustonTX 77026United States

BACKgrOUND Abdominal wall deficiencies or weakness are a common complication of tem-porary ostomies,and incisional hernias frequently develop after colostomy or ileostomy takedown.The use of synthetic meshes to reinforce the abdominal wall has reduced hernia occurrence.Biologic meshes have also been used to enhance healing,particularly in contaminated conditions.reinforced tissue matrices(r-TMs),which include a biologic scaffold of native extracellular matrix and a syn-thetic component for added strength/durability,are designed to take advantage of aspects of both synthetic and biologic materials.To date,rTMs have not been reported to reinforce the abdominal wall following stoma reversal.METHODS Twenty-eight patients were selected with a parastomal and/or incisional hernia who had received a temporary ileostomy or colostomy for fecal diversion after rectal cancer treatment or trauma.Following hernia repair and proximal stoma closure,rTM(OviTex®1S permanent or OviTex®Lpr)was placed to reinforce the abdominal wall using a laparoscopic,robotic,or open surgical approach.post-operative follow-up was performed at 1 month and 1 year.Hernia recurrence was determined by physical examination and,when necessary,via computed tomo-graphy scan.Secondary endpoints included length of hospital stay,time to return to work,and hospital readmissions.Evaluated complications of the wound/repair site included presence of surgical site infection,seroma,hematoma,wound dehiscence,or fistula formation.rESULTS The observational study cohort included 16 male and 12 female patients with average age of 58.5 years±16.3 years and average body mass index of 26.2 kg/m^(2)±4.1 kg/m^(2).patients presented with a parastomal hernia(75.0%),in-cisional hernia(14.3%),or combined parastomal/incisional hernia(10.7%).Using a laparoscopic(53.6%),robotic(35.7%),or open(10.7%)technique,rTMs(OviTex®Lpr:82.1%,OviTex®1S:17.9%)were placed using sublay(82.1%)or intraperitoneal onlay(IpOM;17.9%)mesh positioning.At 1-month and 1-year follow-ups,there were no hernia r

关键词： reinforced tissue matrix reinforced forestomach matrix Ileostomy Colostomy Ostomy takedown Incisional hernia Abdominal wall

Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese physics B 2024年第2期33卷 108-114页

作者： U.S.Mahabaleshwar g.p.Vanitha L.M.pérez Emad H.Aly I.pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked sheet.With the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is illustrated.The resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity transformations.The transformed differential equations are solved analytically.Impacts of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted graphically.The skin friction and Nusselt number were also evaluated.In addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching one.Further,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O nanofluid.Furthermore,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

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Heterogeneity of mature oligodendrocytes in the central nervous system

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Neural regeneration research 2025年第5期20卷 1336-1349页

作者： Chao Weng Adam M.r.groh Moein Yaqubi Qiao-Ling Cui Jo Anne Stratton g.r.Wayne Moore Jack p.Antel Neuroimmunology Unit Montreal Neurological Institute-HospitalDepartment of Neurology and NeurosurgeryMcGill UniversityMontrealQCCanada Department of Neurology Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina

Mature oligodendrocytes form myelin sheaths that are crucial for the insulation of axons and efficient signal transmission in the central nervous system.recent evidence has challenged the classical view of the functionally static mature oligodendrocyte and revealed a gamut of dynamic functions such as the ability to modulate neuronal circuitry and provide metabolic support to axons.Despite the recognition of potential heterogeneity in mature oligodendrocyte function,a comprehensive summary of mature oligodendrocyte diversity is lacking.We delve into early 20th-century studies by robertson and río-Hortega that laid the foundation for the modern identification of regional and morphological heterogeneity in mature oligodendrocytes.Indeed,recent morphologic and functional studies call into question the long-assumed homogeneity of mature oligodendrocyte function through the identification of distinct subtypes with varying myelination preferences.Furthermore,modern molecular investigations,employing techniques such as single cell/nucleus rNA sequencing,consistently unveil at least six mature oligodendrocyte subpopulations in the human central nervous system that are highly transcriptomically diverse and vary with central nervous system region.Age and disease related mature oligodendrocyte variation denotes the impact of pathological conditions such as multiple sclerosis,Alzheimer's disease,and psychiatric disorders.Nevertheless,caution is warranted when subclassifying mature oligodendrocytes because of the simplification needed to make conclusions about cell identity from temporally confined investigations.Future studies leveraging advanced techniques like spatial transcriptomics and single-cell proteomics promise a more nuanced understanding of mature oligodendrocyte heterogeneity.Such research avenues that precisely evaluate mature oligodendrocyte heterogeneity with care to understand the mitigating influence of species,sex,central nervous system region,age,and disease,hold promise for the development of therapeutic

关键词： aging central nervous system diseases electron microscopy heterogeneity immunohistochemistry myelin sheath natural history neuroglia oligodendroglia single-cell gene expression analysis

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Magnesium oxide(MgO) nanoadsorbents in wastewater treatment: A comprehensive review

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Journal of Magnesium and Alloys 2024年第5期12卷 1709-1773页

作者： H.C.S.perera V.gurunanthanan Anoop Singh M.M.M.g.p.g.Mantilaka g.Das Sandeep Arya Department of physics Khalifa University postgraduate Institute of Science University of Peradeniya Department of Humanities and Sciences Guru Nanak Institutions Technical Campus Centre for global Health research Saveetha Medical College and Hospitals Saveetha Institute of Medical and Technical Sciences Department of physics University of Jammu

Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge, necessitating effective and sustainable separation techniques. This review article provides a detailed examination of magnesium oxide(MgO) nanoparticles as an innovative nanoadsorbent for wastewater treatment, with a specific focus on heavy metal and dye removal. The review comprehensively explores various aspects of MgO nanoparticles, including their structural characteristics and synthesis techniques. The article delves into the morphology and crystallographic arrangement of MgO nanoparticles, offering insights into their structural attributes. given the complexity of adsorption processes, the review identifies and analyzes parameters influencing the adsorption efficiency of MgO nanoparticles, such as temperature, pH, contact time, initial concentration, and co-existing ions. The interplay between these parameters and the adsorption capability of MgO nanoparticles emphasizes the importance of optimizing operational conditions. Furthermore, the review assesses various synthesis methods for MgO nanoparticles, including sol-gel, hydrothermal, precipitation, green synthesis, solvothermal, and template-assisted techniques. It discusses the advantages, limitations, and resulting nanoparticle characteristics of each method, enabling readers to grasp the implications of synthesis processes on adsorption efficiency. This comprehensive review consolidates current insights into the effectiveness of MgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to MgO nanoparticles. Moreover, there is a need to investigate the use of MgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.

关键词： MgO nanoparticles Nanoadsorbent Wastewater treatment Heavy metals Dye separation Adsorption Synthesis methods

Stability Analysis of DC Microgrid Clusters Based on Step-by-step System Matrix Building Algorithm

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Journal of Modern power Systems and Clean Energy 2024年第3期12卷 900-912页

作者： K.Jithin N.Mayadevi r.Hari Kumar V.p.Mini IEEE the Department of Electrical Engineering College of Engineering Trivandrum APJ Abdul Kalam Technological University (APJAKTU) Senior Member

DC microgrids(DCMgs) are made up of a network of sources and loads that are connected by a number of power electronic converters(pECs). The increase in the number of these pECs instigates major concerns in system stability. While interconnecting the microgrids to form a cluster, the system stability must be ensured. This paper proposes a novel stepby-step system matrix building(SMB) algorithm to update the system matrix of an existing DCMg cluster when a new microgrid is added to the cluster through a distribution line. The stability of the individual DCMgs and the DCMg cluster is analyzed using the eigenvalue method. Further, the particle swarm optimization(pSO) algorithm is used to retune the controller gains if the newly formed cluster is not stable. The simulation of the DCMg cluster is carried out in MATLAB/Simulink environment to test the proposed algorithm. The results are also validated using the Op4510 real-time simulator(rTS).

关键词： power system stability Stability criteria Microgrids Transfer functions Clustering algorithms Voltage control Eigenvalues and eigenfunctions