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Pleistocene glaciation advances the cryptic speciation of Stellera chamaejasme *** a major biodiversity hotspot

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Journal of Integrative Plant Biology 2024年第6期66卷 1192-1205页

作者： santosh kumar Rana Hum kala Rana Jacob BLandis Tianhui kuang Juntong chen Hengchang Wang Tao Deng charles c.Davis Hang Sun cAS key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Arkansas Biosciences Institute Arkansas State UniversityJonesboroArkansas 72401USA School of Integrative Plant Science Section of Plant Biology and the L.H.Bailey HortoriumCornell UniversityIthacaNew York 14853USA BTI computational Biology center Boyce Thompson InstituteIthacaNew York 14853USA cAS key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture Chinese Academy of SciencesWuhan Botanical GardenWuhan 430074China Department of Organismic and Evolutionary Biology HerbariaHarvard UniversityCambridgeMassachusetts 02138USA

The mountains of Southwest china comprise a significant large mountain range and biodiversity hotspot imperiled by global climate *** high species diversity in this mountain system has long been attributed to a complex set of factors,and recent large-scale macroevolutionary investigations have placed a broad timeline on plant diversification that stretches from 10 million years ago(Mya)to the *** our increasing understanding of the temporal mode of speciation,finer-scale populationlevel investigations are lacking to better refine these temporal trends and illuminate the abiotic and biotic influences of cryptic *** is largely due to the dearth of organismal sampling among closely related species and populations,spanning the incredible size and topological heterogeneity of this *** study dives into these evolutionary dynamics of speciation using genomic and ecomorphological data of Stellera chamaejasme *** identified four previously unrecognized cryptic species having indistinct morphological traits and large metapopulation of evolving lineages,suggesting a more recent diversification(~2.67-0.90 Mya),largely influenced by Pleistocene glaciation and biotic *** factors likely influenced allopatric speciation and advocated cyclical warming–cooling episodes along elevational gradients during the *** study refines the evolutionary timeline to be much younger than previously implicated and raises the concern that projected future warming may influence the alpine species diversity,necessitating increased conservation efforts.

关键词： cryptic speciation glacial-interglacial Hengduan Mountains north-south migration Stellera chamaejasme

Paleo-Mesoarchean sedimentary record in the Dharwar craton,India:Implications for Archean ocean oxygenation

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Geoscience Frontiers 2024年第1期15卷 126-154页

作者： G.Harshitha c.Manikyamba M.santosh cheng-Xue Yang A.keshav krishna V.V.Sesha Sai I.Panduranga Reddy cSIR-National Geophysical Research Institute(NGRI) Uppal RoadHyderabad 500007India Department of Geology Osmania UniversityHyderabad 500007India School of Earth Science and Resources China University of GeosciencesBeijing 100083China Department of Earth Science University of AdelaideAdelaide SA5005Australia Yonsei Frontier Lab Yonsei UniversitySeoul 03722Republic of Korea Geological Survey of India State UnitNagpurIndia

The early Archean oceans were marked by significant redox changes which have subsequently shaped the Earth’s *** chemical sediments of banded Iron and Manganese formations provide important geochemical proxies for these historical shifts in the redox conditions and to trace the ancient sedimentation patterns and *** this study,we investigate the proto-ore of the Archean Mn-formations of the Sandur,chitradurga and Shimoga greenstone belts of Dharwar craton of southern Peninsular India,which is geochemically characterised as quartz arenites,Mn-arenites,Fe-arenites,Mn-argillites and *** geochemical systematics suggest their deposition in shallow to deeper shelf in the Archean *** detrital zircon U-Pb systematics of Mn arenites and argillites indicate their maximum depositional age of 3230±52 Ma representing the oldest onset of sedimentation during the Paleo-Mesoarchean timeframe in the chitradurga Group of Dharwar *** detrital influx proxies suggest variations in sedimentation rates associated with the Archean transgressive-regressive cycles and fluctuating hydrodynamic conditions,together reflecting an increasing trend in the contributions of recycled sediment from Sandur to chitradurga and Shimoga greenstone *** available detrital zircon ages of the Mn arenites and argillites from these greenstone belts indicate a~600 Ma prolonged period of Mn deposition for which high-T hydrothermal fluids from Archean mid-oceanic ridges supplied the *** trace element compositions of the concordant detrital zircons suggest 3.3-3.1 Ga Dharwar basement TTG/granitoid source which is corroborated by the zircon crystallization temperatures of 690-820℃.The source-normalisedα-dose rates of the detrital zircons signify greater degrees of sediment transport and multi-cycle nature which correspond to the earliest episode of crustal growth in the Indian sub-continent associated with the Mesoarchean Ur supercontinent.T

关键词： Mn-arenites-argillites Dharwar craton Zircon U-Pb geochronology Passive margin sediments Ocean oxygenation

Study of Structural, Optical, Electrical and Dielectric Properties of Gd-Doped ZnO composites Synthesized by Solid State Reaction Method

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Open Journal of composite Materials 2024年第2期14卷 91-108页

作者： santosh kumar kundara kanhaiya chawla Dinesh kumar Yadav chhagan Lal Balram Tripathi Narendra Jakhar Department of Physics University of Rajasthan Jaipur India Sw. P.N.k.S. Government PG college Dausa India Government PG college Pratapgarh India S.S. Jain Subodh PG (Autonomous) college Jaipur India

In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn1−xGdxO, x = 0, 0.05, 0.10) prepared by solid-state reaction method. XRD spectra confirm the wurtzite hexagonal phase with a grain size distribution of 42 - 47 nm. The FT-IR spectra confirm bonding behavior like Zn-O, O=c=O, and O-H stretching modes. FESEM micrographs show that the grains of crystallites possess nearly spherical morphology. Optical absorption spectra confirm that the optical band gap decreases systematically from 3.19 eV to 3.15 eV for x = 0.0 to x = 0.10 samples. For all samples, PL spectra exhibited near-band emission, blue emission, and green emission peaks. The dielectric constant decreases as the applied frequency increases. Hall effect results show that with increasing doping concentration of Gd, mobility and resistivity increase while bulk concentration decreases. current-Voltage study shows that current increases when temperature is increased. Rare earth-doped ZnO is potential material used for optoelectronics and spintronics device applications. Properties of Gd-doped ZnO are studied by various research groups, but dielectric studies are limitedly reported. Therefore, the present research work aims to study the change of electrical, optical, and dielectric properties of Gd-doped ZnO for device applications.

关键词： ZnO:Gd composites Optical Band Gap Green Emission Dielectric constant

Paleozoic tectonic evolution of the proto-korean Peninsula along the East Asian continental margin from detrital zircon U-Pb geochronology and Hf isotope geochemistry

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Geoscience Frontiers 2024年第1期15卷 97-117页

作者： Yirang Jang Sung Won kim Vinod O.Samuel Sanghoon kwon Seung-Ik Park M.santosh keewook Yi Department of Earth and Environmental Sciences Chonnam National UniversityGwangju 61186Republic of Korea Geology Division Korea Institute of Geoscience and Mineral ResourcesDaejeon 34132Republic of Korea Department of Earth System Sciences Yonsei UniversitySeoul 03722Republic of Korea Department of Geology Kyungpook National UniversityDaegu 41566Republic of Korea School of Earth Sciences and Resources China University of Geosciences BeijingBeijing 100083China Department of Earth Science University of AdelaideAdelaide SA 5005Australia Yonsei Frontiers Lab Yonsei UniversitySeoul 03722Republic of Korea Division of Earth and Environmental Sciences Korea Basic Science InstituteChungbuk 28119Republic of Korea

Detrital zircon geochronology and Hf isotope analysis can be used for inferring provenance characteristics,and to evaluate the tectonic evolution of sedimentary basins and their link with regional *** Paleozoic sequences of the Okcheon Belt consist of the Lower Paleozoic Joseon and the Upper Paleozoic Pyeongan supergroups with Middle Paleozoic hiatus locally on top of the Neoproterozoic bimodal volcanic rocks,reflecting an intracontinental rift setting between the two basements(*** and Yeongnam massifs)at southern part of the korean *** detrital zircon U-Pb ages and Lu-Hf isotope results show that all these Paleozoic strata commonly have Paleoproterozoic and Paleozoic zircon ages with rare Meso-to Neoproterozoic *** individual zircon populations display following features,allowing estimation of their sedimentary provenances:(i)The Paleoproterozoic zircons(ca.1.85 Ga and 2.50 Ga)with similar ranges ofεHf(t)values are most common in the basement rocks of the korean Peninsula,and were sourced from both the Gyeonggi and Yeongnam massifs.(ii)The Meso-to Neoproterozoic zircons,preserved only in the Middle to Late cambrian clastic sedimentary rocks within the carbonate sequences probably reflect proximal provenance.(iii)The youngest Paleozoic zircons of each formation,almost coincident with their deposition ages,suggest presence of syndepositional magmatism,indicating proximal magmatic sources during their deposition.(iv)The cambrian-Ordovician zircons,from the Lower Paleozoic sequences,but rare in the successive Upper Paleozoic sequences,suggest a provenance change after the hiatus between the two sedimentary successions.(v)The Permian zircons showing differentεHf(t)values indicate that detrital sources were varied at that *** integrated results in our study suggest provenance variability linked to diverse tectonic environments,reflecting prolonged subduction-related crustal evolution of the proto-korean Peninsula during the Paleozo

关键词： Detrital zircon U-Pb and Hf isotopes Paleozoic metasedimentary rocks Okcheon Belt Taebaeksan zone korean Peninsula

Helicobacter pylori and other Helicobacter species DNA in human bile samples from patients with various hepato-biliary diseases

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World Journal of Gastroenterology 2006年第14期12卷 2181-2186页

作者： santosh k Tiwari Aleem A khan Mohd Ibrahim Mohd Aejaz Habeeb c M Habibullah center for Liver Research and Diagnostics Deccan college of Medical Sciences KanchanbaghHyderabad 500 058Andhra PradeshIndia center for Liver Research and Diagnostics Deccan college of Medical Sciences KanchanbaghHyderabad 500 058Andhra PradeshIndia Department of GastroenterologyDeccan College of Medical Sciences Hyderabad 500 058Andhra PradeshIndia

AIM： To investigate the presence of Helicobacter species by nested PcR of 16S rRNA genes followed by the presence of Flelicobacter pylori （H pylori） 16S rRNA, ureA, cagA genes in bile obtained at endoscopic retrograde cholangio-pancreatography （ERcP） from 60 Indian subjects. METHODS： Sixty bile samples were obtained from patients diagnosed with various hepato-biliary diseases and control subjects at ERcP. PcR analysis was carried out using primers for Helicobacter genus 16S rRNA gene and H pylori （16S rRNA, urea and cagA） genes. Gastric H pylori status was also assessed from biopsies obtained at endoscopy from patients with various hepatobiliary diseases and controls. The control group mainly consisted of subjects with gastric disorders. Sequencing analysis was performed to confirm that PcR products with 16S rRNA and cagA primers were derived from H pylori. RESULTS No Helicobacters were grown in culture from the bile samples. Helicobacter DNA was detected in bile of 96.7% and 6.6% of groups Ⅰ and Ⅱ respectively. Ten from group Ⅰ were positive for 16S rRNA and ureA and 9 were positive for cagA gene. In contrast of the 2 from the control, 1 amplified with 16S rRNA, ureA and cagA primers used. The sequences of the 16S rRNA genes and cagA were 99% similar to Helicobacter pylori. cONcLUSION： Helicobacters are associated with the pathogenesis of various hepato-biliary disorders.

关键词： Helicobacter pylori Bile Hepato-biliary diseases PcR, Sequence analysis

Detrital zircon U-Pb geochronology of stromatolitic carbonates from the greenstone belts of Dharwar craton and cuddapah basin of Peninsular India

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Geoscience Frontiers 2020年第1期11卷 229-242页

作者： Arubam c.khelen c.Manikyamba Li Tang M.santosh k.S.V.Subramanyam Th Dhanakumar Singh Academy of Scientific and Innovative Research(AcSIR) CSIR(Council of Scientific and Industrial Research)National Geophysical Research Institute(NGRI)Uppal RoadHyderabad500007India cSIR-NGRI Uppal RoadHyderabad500007India School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China Department of Earth Sciences University of AdelaideAdelaideAustralia

Oldest rocks are sparsely distributed within the Dharwar craton and little is known about their involvement in the sedimentary sequences which are present in the Archean greenstone successions and the Proterozoic cuddapah *** carbonates are well preserved in the Neoarchean greenstone belts of Dharwar craton and cuddapah Basin of Peninsular India displaying varied morphological and geochemical *** this study,we report results from U-Pb geochronology and trace element composition of the detrital zircons from stromatolitic carbonates present within the Dharwar craton and cuddapah basin to understand the provenance and time of accretion and *** UPb ages of the detrital zircons from the Bhimasamudra and Marikanve stromatolites of the chitradurga greenstone belt of Dharwar craton display ages of 3426±26 Ma to 2650±38 Ma whereas the Sandur stromatolites gave an age of 3508±29 Ma to 2926±36 Ma suggesting Paleo-to Neoarchean *** U-Pb detrital zircons of the Tadpatri stromatolites gave an age of 2761±31 Ma to1672±38 Ma suggesting Neoarchean to Mesoproterozoic *** Rare Earth Element(REE)patterns of the studied detrital zircons from Archean Dharwar craton and Proterozoic cuddapah basin display depletion in light rare earth elements(LREE)and enrichment in heavy rare earth elements(HREE)with pronounced positive ce and negative Eu anomalies,typical of magmatic *** trace element composition and their relationship collectively indicate a mixed granitoid and mafic source for both the Dharwar and cuddapah *** 3508±29 Ma age of the detrital zircons support the existence of 3.5 Ga crust in the Western Dharwar *** overall detrital zircon ages(3.5-2.7 Ga)obtained from the stromatolitic carbonates of Archean greenstone belts and Proterozoic cuddapah basin(2.7-1.6 Ga)collectively reflect on^800-900 Ma duration for the Precambrian stromatolite deposition in the Dharwar craton.

关键词： Stromatolites Archean Proterozoic Dharwar craton cuddapah basin Detrital zircons

2D Ti_(3)c_(2)T_(x)MXene-derived self-assembled 3D TiO_(2)nanoflowers for nonvolatile memory and synaptic learning applications

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Journal of Materials Science & Technology 2023年第19期150卷 1-10页

作者： Atul c.khot Tukaram D.Dongale kiran A.Nirmal Jayan k.Deepthi santosh S.Sutar Tae Geun kim School of Electrical Engineering Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841Republic of Korea computational Electronics and Nanoscience Research Laboratory School of Nanoscience and BiotechnologyShivaji UniversityKolhapur 416004India Rajagiri School of Engineering and Technology(Autonomous) Rajagiri ValleyKakkanadKochiKerala 682039India Yashwantrao chavan School of Rural Development Shivaji UniversityKolhapur 416004India

Two-dimensional(2D)semiconducting materials and transition-metal oxides are promising materials for nonvolatile memory and brain-inspired neuromorphic computing ***,it remains chal-lenging to obtain high-quality stacked 2D films with low energy consumptions(or drive currents)be-cause of their high interfacial *** this study,we synthesized 2D Ti_(3)c_(2)T_(x)MXene-derived three-dimensional(3D)TiO_(2)nanoflowers(NFs)as a feasible resistive switching(RS)material with outstanding electronic properties and synaptic learning *** electrical and optical characteristics of the synthesized material were determined through density functional theory *** measure-ments of the Al/Ti_(3)c_(2)T_(x)-TiO_(2)NF/Pt memory device indicated the occurrence of forming-free switching phenomena with extremely low switching voltages(0.68-0.53 V),stable ON/OFF ratio(2.3×103),and retention greater than 105 *** Holt-Winters exponential smoothing technique was used for mod-eling and predicting the switching voltages of the RS *** mechanism underlying the reliable RS was confirmed by observing the dense conductive filaments through conductive atomic force ***,the 2D Ti_(3)c_(2)T_(x)MXene-derived 3D TiO_(2)NF-based RS device mimicked the po-tentiation/depression and spike-time-dependent plasticity of a biological ***,a convolutional neural network was implemented based on the observed synaptic weights of Al/Ti_(3)c_(2)T_(x)-TiO_(2)NF/Pt for image-edge detection.

关键词： MXene Ti_(3)c_(2)T_(x)-TiO_(2)nanoflowers Resistive switching Synaptic learning Density functional theory Time-series analysis

Materials Design on the Origin of Gap States in a High-κ/GaAs Interface

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Engineering 2015年第3期1卷 372-377页

作者： Weichao Wang cheng Gong ka Xiong santosh k.c. Robert M.Wallace kyeongjae cho Department of Materials Science and Engineering The University of Texas at Dallas college of Electronic Information and Optical Engineering Nankai University

Given the demand for constantly scaling micro- electronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf（Zr）O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant （high-κ） dielectrics, the electron mobility in the conventional Si channel degrades due to coulomb scattering, surface-roughness scattering, remotephonon scattering, and dielectric-charge trapping.Ⅲ-Ⅴ and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf（Zr）O2/Ⅲ-Ⅴ（Ge） has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding configurations at Hf（Zr）O2/Ⅲ-Ⅴ（Ge） interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize first- principle calculations to investigate the interface between HfO2 and GaAs. Our study shows that As--As dimer bonding, Ga partial oxidation （between 3＋ and 1＋） and Ga- dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.

关键词： high-mobility device high-κ/Ⅲ-Ⅴ interface interfacial gap states first-principle calculations

Synthesis of N1-3-{（4-Substituted aryl-3-chloro-2-oxo- azetidine）-iminocarbamyl}-propyl-6-nitroindazole Derivatives and Their Biological Significance

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chinese Journal of chemistry 2011年第8期29卷 1745-1752页

作者： Samadhiya, Pushkal Sharma, Ritu Srivastava, santosh k. Srivastava, Savitri D. Synthetic Organic chemistry Laboratory Department of Chemistry Dr. H. S. Gour University (A Central Univer- sity) Sagar M.P. 470003 India

Synthesis of N1-3-{（4-substitute daryl-3-chloro-2-oxo-azetidine）-iminocarbamyl}-propyl-6-nitroindazole 4a-- 4s was conducted by a conventional method. All the compounds were synthesized and characterized by IR, 1H NMR, 13c NMR, FAB-Mass techniques and chemical methods. All the final synthesized compounds were evaluated for their antimicrobial activity and antitubercular activity with MIc values against some selected microorganisms.

关键词： synthesis 6-nitroindazole 2-azetidinone biological activity