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Phanerozoic co-evolution of O2-CO2 and ocean habitability

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National Science Review 2024年第6期11卷 18-21页

作者： Zunli Lu rosalind E.M.Rickaby Jonathan L.Payne Ashley N.Prow Department of Earth & Environmental Sciences Syracuse University Department of Earth Sciences University of Oxford Department of Earth and Planetary Sciences Stanford University

Atmospheric carbon dioxide and oxygen concentrations are partially linked via the geological cycle of organic carbon （Fig. 1A–C; e.g. CO2+H2O■CH2O+O2）. The history of these two biologically active components, controls on their concentrations, and implications for the complexity of the biosphere and habitability of Earth have been hotly debated, but are generally considered independently.

关键词： CO2-CONCENTRATINg MECHANISM OXYgEN EVOLUTION ANOXIA

Steroidal scaffold decorations in Solanum alkaloid biosynthesis

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Molecular Plant 2024年第8期17卷 1236-1254页

作者： rosalind Lucier Mohamed O.Kamileen Yoko Nakamura Sofiia Serediuk Ranjit Barbole Jens Wurlitzer Maritta Kunert Sarah Heinicke Sarah E.O'Connor Prashant D.Sonawane Department of Natural Product Biosynthesis Max Planck Institute for Chemical Ecology07745 JenaGermany Research group Biosynthesis and NMR Max Planck Institute for Chemical Ecology07745 JenaGermany Biochemical Sciences Division CSIR-National Chemical LaboratoryPune 411008MaharashtraIndia

Steroidal glycoalkaloids(SgAs)are specialized metabolites produced by hundreds of Solanum species,including important vegetable crops such as tomato,potato,and *** it has been known that SgAs play important roles in defense in plants and“anti-nutritional"effects(e.g.,toxicity and bitterness)to humans,many of these molecules have documented anti-cancer,anti-microbial,antiinflammatory,anti-viral,and anti-pyretic *** these,α-solasonine andα-solamargine isolated from black nightshade(Solanum nigrum)are reported to have potent anti-tumor,anti-proliferative,and anti-inflammatory ***,α-solasonine andα-solamargine,along with the core steroidal aglycone solasodine,are the most widespread SgAs produced among the Solanum ***,it is still unknown how plants synthesize these bioactive steroidal *** comparative metabolomictranscriptome-guided approach,biosynthetic logic,combinatorial expression in Nicotiana benthamiana,and functional recombinant enzyme assays,here we report the discovery of 12 enzymes from *** that converts the starting cholesterol precursorto solasodine aglycone,and the downstreamα-solasonine,α-solamargine,and malonyl-solamargine SgA *** further identified six enzymes from cultivated eggplant that catalyze the production ofα-solasonine,α-solamargine,and malonyl-solamargine SgAs from solasodine aglycone via glycosylation and atypical malonylation *** work provides the gene tool box and platform for engineering the production of high-value,steroidal bioactive molecules inheterologoushosts usingsyntheticbiology.

关键词： steroidal glycoalkaloids Solanum biosynthetic pathway α-solamargine malonyl-solamargine specialized metabolites

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： g.Murali Division of Research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called geopolymer based ultra-highperformance concrete(gUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of gUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of gUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in gUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,gUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre geopolymer Silica fume Alkaline activators

Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

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Journal of Forestry Research 2024年第1期35卷 213-228页

作者： Fatma Selcen Sakar gürcan güleryüz Department of Biology Section Ecology GörükleGraduate School of Natural and Applied ScienceUniversity of Bursa Uludağ16059 NilüferBursaTurkey Department of Biology Section Ecology GörükleFaculty of Science and ArtsUniversity of Bursa Uludağ16059 NilüferBursaTurkey

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest *** the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 *** locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest *** had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),*** the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N *** acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

关键词： Oldest forest communities Nitrogen mineralization Nitrification Tannic acid Total phenolic Litter

Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

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直面实验室欺诈

科学新闻 2024年第2期 57-58页

作者： rosalind A.Coleman 倪伟波

星期一，当C.B.走进我的办公室时，他愁眉苦脸的样子让我知道这是个坏消息。3周前，我的两名博士后出现在我的门口，勉强忍住泪水。他们确信另一个博士后同事伪造了数据，因为他们从未见过约翰（化名）使用其在实验室会议上展示的最新...

星期一，当C.B.走进我的办公室时，他愁眉苦脸的样子让我知道这是个坏消息。3周前，我的两名博士后出现在我的门口，勉强忍住泪水。他们确信另一个博士后同事伪造了数据，因为他们从未见过约翰（化名）使用其在实验室会议上展示的最新数据所必需的设备。起初，我以为他们弄错了，那时我已经在全国性会议上几次展示了约翰的数据，而且当时我们正在写一篇论文，这篇论文将对我们的领域产生巨大影响。但我不能忽视他们的怀疑。我给学校的廉政官员打了电话，见了学院院长，还聘请实验室前资深科学家C.B.重复最关键的实验。

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Harmonics in the Squirrel Cage Induction Motor Analytic Calculation Part III: Influence on the Torque-speed Characteristic

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 86-102页

作者： g.Kovács the ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor Squirrel cage rotor Space harmonics Synchronous parasitic torques

Neuroimaging in atypical normal tension glaucoma:debating routine implementation in the absence of classic neurological findings

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 509-517页

作者： Umay güvenç gülizar Demirok güner Üney Selma Uzman Ophthalmology Department Ankara Training and Research HospitalAnkara 06230Turkey

●AIM:To assess the necessity of neuroimaging in patients with neurological or atypical findings of normal tension glaucoma(NTg)who do not exhibit typical glaucoma manifestations.●METHODS:A retrospective analysis was conducted on 90 atypical NTg patients who underwent cranial magnetic resonance imaging(MRI)due to atypical *** demographic characteristics,clinical parameters,and radiological findings were recorded.●RESULTS:Among the patients,66.7%had abnormal radiology results,with the most common findings being gliosis(34.4%),sequelae of cerebrovascular events and vascular malformations(14.4%),and benign intracranial mass lesions(11%).Non-glaucomatous visual field defects were more frequently observed in patients with abnormal neuroimaging ***,there were no significant differences in intraocular pressure,optic disc parameters,retinal nerve fiber layer thickness,and visual field indices between patients with normal and abnormal radiological *** mean age of the patients was ***,there was a significant age difference,with the abnormal radiology group having a higher median age(P=0.021).●CONCLUSION:The study highlights the importance of cranial imaging in older NTg patients to detect underlying pathologies and prevent *** suggests that neuroimaging may be warranted in NTg patients with atypical visual field defects incompatible with ***,routine neuroimaging in all NTg patients without classic neurological signs may not be necessary.

关键词： normal tension glaucoma neuroimaging atypical visual field defects