We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 B.Exoplanet candidates...We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 B.Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite(TESS)are suitable for further follow-up observations by ground-based telescopes with small and medium apertures.The analysis is performed based on data from several telescopes worldwide,including telescopes in the Sino-German multiband photometric campaign,which aimed at confirming TESS Objects of Interest(TOIs)using ground-based small-aperture and medium-aperture telescopes,especially for long-period targets.TOI-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric data.We measure an orbital period of 2.310644±0.000001 days,the radius is 0.767+0.045-0.041RJ and the amplitude of the RV curve is 69.4_(-7.3)^(+7.9)m s^(-1).TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data,whose orbital period is 5.963054+0.000002-0.000001days,radius is 0.947+0.035-0.033 R_(J) and amplitude of the RV curve is 9849_(-40)^(+42)ms^(-1).展开更多
Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caus...Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caused by a variety of reasons,including ions diffusion,surface and grain boundary defects,etc.In this work,the cross-linkable tannic acid(TA)is introduced to modify perovskite film through post-treatment method.The numerous organic functional groups(–OH and C=O)in TA can interact with the uncoordinated Pb^(2+)and I^(-)ions in perovskite,thus passivating defects and inhibiting ions diffusion.In addition,the formed TA network can absorb a small amount of the residual moisture inside the device to protect the perovskite layer.Furthermore,TA modification regulates the energy level of perovskite,and reduces interfacial charge recombination.Ultimately,following TA treatment,the device efficiency is increased significantly from 21.31%to 23.11%,with a decreased hysteresis effect.Notably,the treated device shows excellent air,thermal,and operational stability.In light of this,the readily available,inexpensive TA has the potential to operate as a multipurpose interfacial modifier to increase device efficiency while also enhancing device stability.展开更多
Background:Oral squamous cell carcinoma(OSCC)represents a prevalent malignancy in the oral and maxillofacial area,having a considerable negative impact on both the quality of life and overall survival of affected indi...Background:Oral squamous cell carcinoma(OSCC)represents a prevalent malignancy in the oral and maxillofacial area,having a considerable negative impact on both the quality of life and overall survival of affected individuals.Our research endeavors to leverage bioinformatic approaches to elucidate oncogenic signaling pathways,with the ultimate goal of gaining deeper insights into the molecular underpinnings of OSCC pathogenesis,and thus laying the groundwork for the development of more effective therapeutic and preventive strategies.Methods:Differential expression analysis was performed on mRNA data from tumor and normal tissue groups to identify genes associated with OSCC,using The Cancer Genome Atlas database.Predictions of oncogenic signaling pathways linked to differentially expressedmRNAs were made,and these results were presented visually using R software,using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichments.Results:GO and KEGG analyses of 2938 differentially expressed genes in OSCC highlighted their significant involvement in various biological processes.Notably,these processes were related to the extracellular matrix,structural organization,connective tissue development,and cell cycle regulation.Conclusions:The comprehensive exploration of gene expression patterns provides valuable insights into potential oncogenic mechanisms in OSCC.展开更多
Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen disso...Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen dissolved liquid leadbismuth eutectic(LBE-O).Both static and dynamic simulation results indicate that the early stage oxidation and dissolution behaviors of bcc Fe show strong orientation dependence under the liquid LBE environments,which may explain the experimental observations of uneven interface between iron-based materials and liquid LBE.Our investigations show that it is the delicate balance between the oxide growth and metal dissolution that leads to the observed corrosion anisotropy for bcc Fe contacting with liquid LBE-O.展开更多
Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissi...Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissions in China, it will be necessary to mitigate at least some of these emissions to achieve this goal. Studies by the International Energy Agency(IEA) indicate CCS technology has the potential to contribute 14% of global emission reductions, followed by 40% of higher energy efficiency and 35% of renewable energy, which is considered as the most promising technology to significantly reduce carbon emissions for current coal-fired power plants.Moreover, the announcement of a Chinese national carbon trading market in late 2017 signals an opportunity for the commercial deployment of CO_2 capture technologies.Currently, the only commercially demonstrated technology for post-combustion CO_2 capture technology from power plants is solvent-based absorption. While commercially viable, the costs of deploying this technology are high. This has motivated efforts to develop more affordable alternatives, including advanced solvents, membranes,and sorbent capture systems. Of these approaches, advanced solvents have received the most attention in terms of research and demonstration. In contrast, sorbent capture technology has less attention, despite its potential for much lower energy consumption due to the absence of water in the sorbent. This paper reviews recent progress in the development of sorbent materials modified by amine functionalities with an emphasis on material characterization methods and the effects of operating conditions on performance. The main problems and challenges that need to be overcome to improve the competitiveness of sorbent-based capture technologies are discussed.展开更多
Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F ...Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F intergenic spacer by maximum parsimony and maximum likelihood methods. The results showed that: (a) sect. Stenophora was a strongly supported monophyletic group; (b) D. rockii, D. membranacea, D. banzhuana, and D. simulans formed a moderately supported monophyletic group, and D. prazeri was weakly supported to be sister to this group; (c) D. althaeoides and D. nipponica ssp. nipponica formed a moderately supported clade, and D. nipponica ssp. rosthornii was not a member of this clade; (d) D. zingiberensis and D. sinoparviflora showed a moderate to strong sister relationship; and (e) D. collettii var. hypoglauca and D. collettii var. collettii were sister to each other, but with only weak support.展开更多
By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 ...By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 UMa manifests a shallow contact configuration, while V509 Cam exhibits a medium contact configuration. Given that both of them are totally eclipsing binaries, the physical parameters derived only by the photometric light curves are reliable. Meanwhile, the period changes of the two targets were analyzed based on all available eclipsing times. We discovered that V342 UMa shows long-term period decrease with a rate of-1.02(±0.54)× 10^-7 d yr^-1 and that V509 Cam displays long-term period increase with a rate of 3.96(±0.90)× 10^-8 d yr^-1. Both the conservative mass transfer and angular momentum loss via magnetic stellar winds can be used to interpret the long-term period decrease of V342 UMa. The longterm period increase of V509 Cam can be explained by mass transfer from the less massive star to the more massive one. The absolute parameters of the two binaries were estimated according to their Gaia distances and our derived photometric solution results. This method can be extended to other contact binaries without radial velocities but with reliable photometric solutions. Their evolutionary states were investigated and we found that they reveal properties that are identical to other W-subtype contact systems.展开更多
The first charge-coupled device photometric light curves in B,V,Rc,and Ic bands of the short-period contact binary star OQ Cam are presented.Through analyzing the light curves with the WilsonDevinney code,it is found ...The first charge-coupled device photometric light curves in B,V,Rc,and Ic bands of the short-period contact binary star OQ Cam are presented.Through analyzing the light curves with the WilsonDevinney code,it is found that OQ Cam is a W-type shallow contact binary star with a contact degree of f=20.2%.Based on the O-C analyzing,the orbit period displays a long term increasing with a rate of d P/dt=4.40×10^-7 d yr-1.The increasing in orbit period can be interpreted by mass transfer from the less massive component to the more massive one.As the orbit period increases,OQ Cam would evolve from the present shallow contact configuration to a non-contact stage.So it may be a potential candidate to confirm the thermal relaxation oscillation theory.展开更多
The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Ce...The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Cep is a median-contact binary(f=33.9(±4.9)%)with a mass ratio of 0.285.It is a W-subtype contact binary,that is,the component with less mass is hotter than the component with more mass,and the light curves are asymmetric(O’Connell effect),which can be explained by the existence of a hot spot on the component with less mass.The orbital inclination is i=88.3°,indicating that it is a totally eclipsing binary,so the parameters obtained are reliable.Through the O-C analyzing,it is found that the orbital period decreases at the rate of P=-3.90(±0.06)×10^(-7)d yr^(-1),which indicates that the mass transfer occurs from the more massive component to the less massive one.展开更多
We conducted photometric and spectroscopic observations of Ross 15 in order to further study the flare properties of this less observed flare star.A total of 28 B-band flares are detected in 128 hr of photometric obse...We conducted photometric and spectroscopic observations of Ross 15 in order to further study the flare properties of this less observed flare star.A total of 28 B-band flares are detected in 128 hr of photometric observations,leading to a total flare rate of 0.22-0.040.04 h-1,more accurate than that provided by previous work.We give the energy range of the B-band flare(1029.5-1031.5 erg) and the flare frequency distribution(FFD) for the star.Within the same energy range,the FFD is lower than that of GJ 1243(M4)and YZ CMi(M4.5),roughly in the middle of those of three M5-type stars and higher than the average FFDs of spectral types> M6.We performed,for the first time for Ross 15,simultaneous high-cadence spectroscopic and photometric observations,resulting in detection of the most energetic flare in our sample.The intensity enhancements of the continuum and Balmer lines with significant correlations between them are detected during the flare,which is the same as those of other deeply studied flare stars with similar spectral type.展开更多
Ti_(3)AlC_(2)samples are irradiated in advance by 3.5 MeV Fe-ion to the fluence of 1.0×10^(16)ion/cm^(2),and then are implanted by 500 keV He-ion with the fluence of 1.0×10^(17)ion/cm^(2)at room temperature....Ti_(3)AlC_(2)samples are irradiated in advance by 3.5 MeV Fe-ion to the fluence of 1.0×10^(16)ion/cm^(2),and then are implanted by 500 keV He-ion with the fluence of 1.0×10^(17)ion/cm^(2)at room temperature.The irradiated samples are investigated by grazing incidence x-ray diffraction(GIXRD)and transmission electron microscopy(TEM).GIXRD results show serious structural distortion,but without amorphization in the irradiated samples.Fe-ion irradiation and He-ion implantation create much more serious structural distortion than single Fe-ion irradiation.TEM results reveal that there are a large number of defect clusters in the damage region,and dense spherical He bubbles appear in the He depositional region.It seems that the pre-damage does not influence the growth of He bubbles,but He-ion implantation influences the pre-created defect configurations.展开更多
As recombination centers of vacancies(Vs)and self-interstitial atoms(SIAs),firstly grain boundaries(GBs)should have strong capability of trapping point defects.In this study,abilities to trap Vs and SIAs of eight symm...As recombination centers of vacancies(Vs)and self-interstitial atoms(SIAs),firstly grain boundaries(GBs)should have strong capability of trapping point defects.In this study,abilities to trap Vs and SIAs of eight symmetric tilt GBs in tungsten are investigated through first-principles calculations.展开更多
The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly...The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.展开更多
Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,...Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the TP.The timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains controversial.In this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin Lake,on the interior TP.Our analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North China.Using Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 ka.This date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the TP.Taken together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.展开更多
The anomalous photovoltaic(APV)effect is promising for high-performance ferroelectric materials and devices in photoelectric applications.However,it is a challenge how to tune the APV effect by utilizing the character...The anomalous photovoltaic(APV)effect is promising for high-performance ferroelectric materials and devices in photoelectric applications.However,it is a challenge how to tune the APV effect by utilizing the characteristic structure of ferroelectrics.Here,a domain engineering strategy is proposed to enhance the APV effect in lead-free 0.88(Na_(0.5)Bi_(0.5)TiO_(3))-0.12(Ba_(1–1.5x)S_(mx)TiO_(3))(NBT-BST)ferroelectric ceramics.By tuning the domain size based on Sm^(3+)doping,a maximum open-circuit voltage(VOC)of 18.1 V is obtained when Sm^(3+)content is 0.75%,which is much larger than its bandgap(Eg).The mechanism of this large VOC originates from the multiple positive effects induced by the small-size domain,where decreasing domain size enhances ferroelectric polarization and net interface barrier potential,leading to a large driving electric field.Moreover,the APV effect exhibits a giant temperature sensitivity due to the dramatic evolution of small-size domain in the temperature field.This work sheds light on the exploration of ferroelectrics with APV effect and inspires their future high-performance optoelectronic device applications.展开更多
Isocitrate dehydrogenase(IDH)mutations frequently occur in lower-grade gliomas and secondary glioblastomas.Mutant IDHs exhibit a gain-of-function activity,leading to the production of D-2-hydroxyglutarate(D-2HG)by red...Isocitrate dehydrogenase(IDH)mutations frequently occur in lower-grade gliomas and secondary glioblastomas.Mutant IDHs exhibit a gain-of-function activity,leading to the production of D-2-hydroxyglutarate(D-2HG)by reducing α-ketoglutarate(α-KG),a central player in metabolism and epigenetic modifications.However,the role ofα-KG homeostasis in IDH-mutated gliomagenesis remains elusive.In this study,we found that low expression of oxoglutarate dehydrogenase(OGDH)was a common feature in IDH-mutated gliomas,as well as inastrocytes.This low expression of OGDH resultedin the accumulation of α-KG and promoted astrocyte maturation.However,IDH1 mutation significantly reducedα-KG levels and increased glutaminolysis and DNA/histone methylation in astrocytes.These metabolic and epigenetic alterations inhibited astrocyte maturation and led to cortical dysplasia in mice.Moreover,our results also indicated that reduced OGDH expression can promote the differentiation of glioma cells,while IDH1 mutations impeded the differentiation of glioma cells with low OGDH by reducing the accumulation ofα-KG and increasing glutaminolysis.Finally,we found that l-glutamine increasedα-KG levels and augmented the differentiation-promoting effects of AGI5198,an IDH1-mutant inhibitor,in IDH1-mutant glioma cells.Collectively,this study reveals that low OGDH expression is a crucial metabolic characteristic of IDH-mutant gliomas,providing a potential strategy for the treatment of IDH-mutant gliomas by targetingα-KG homeostasis.展开更多
基金supported by National Natural Science Foundation of China(NSFC,Grant Nos.U1831209 and U2031144)the research fund of Ankara University(BAP)through the project 18A0759001。
文摘We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 B.Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite(TESS)are suitable for further follow-up observations by ground-based telescopes with small and medium apertures.The analysis is performed based on data from several telescopes worldwide,including telescopes in the Sino-German multiband photometric campaign,which aimed at confirming TESS Objects of Interest(TOIs)using ground-based small-aperture and medium-aperture telescopes,especially for long-period targets.TOI-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric data.We measure an orbital period of 2.310644±0.000001 days,the radius is 0.767+0.045-0.041RJ and the amplitude of the RV curve is 69.4_(-7.3)^(+7.9)m s^(-1).TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data,whose orbital period is 5.963054+0.000002-0.000001days,radius is 0.947+0.035-0.033 R_(J) and amplitude of the RV curve is 9849_(-40)^(+42)ms^(-1).
基金supported by the General Program of Chongqing Natural Science Foundation(CSTB2022NSCQMSX1227 and CSTB2022NSCQ-MSX0459)the supports from the Fundamental Research Funds for the Central Universities(SWU-XDJH202314)。
文摘Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caused by a variety of reasons,including ions diffusion,surface and grain boundary defects,etc.In this work,the cross-linkable tannic acid(TA)is introduced to modify perovskite film through post-treatment method.The numerous organic functional groups(–OH and C=O)in TA can interact with the uncoordinated Pb^(2+)and I^(-)ions in perovskite,thus passivating defects and inhibiting ions diffusion.In addition,the formed TA network can absorb a small amount of the residual moisture inside the device to protect the perovskite layer.Furthermore,TA modification regulates the energy level of perovskite,and reduces interfacial charge recombination.Ultimately,following TA treatment,the device efficiency is increased significantly from 21.31%to 23.11%,with a decreased hysteresis effect.Notably,the treated device shows excellent air,thermal,and operational stability.In light of this,the readily available,inexpensive TA has the potential to operate as a multipurpose interfacial modifier to increase device efficiency while also enhancing device stability.
文摘Background:Oral squamous cell carcinoma(OSCC)represents a prevalent malignancy in the oral and maxillofacial area,having a considerable negative impact on both the quality of life and overall survival of affected individuals.Our research endeavors to leverage bioinformatic approaches to elucidate oncogenic signaling pathways,with the ultimate goal of gaining deeper insights into the molecular underpinnings of OSCC pathogenesis,and thus laying the groundwork for the development of more effective therapeutic and preventive strategies.Methods:Differential expression analysis was performed on mRNA data from tumor and normal tissue groups to identify genes associated with OSCC,using The Cancer Genome Atlas database.Predictions of oncogenic signaling pathways linked to differentially expressedmRNAs were made,and these results were presented visually using R software,using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichments.Results:GO and KEGG analyses of 2938 differentially expressed genes in OSCC highlighted their significant involvement in various biological processes.Notably,these processes were related to the extracellular matrix,structural organization,connective tissue development,and cell cycle regulation.Conclusions:The comprehensive exploration of gene expression patterns provides valuable insights into potential oncogenic mechanisms in OSCC.
基金the National Natural Science Foundation of China(Grant No.U1832206).
文摘Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen dissolved liquid leadbismuth eutectic(LBE-O).Both static and dynamic simulation results indicate that the early stage oxidation and dissolution behaviors of bcc Fe show strong orientation dependence under the liquid LBE environments,which may explain the experimental observations of uneven interface between iron-based materials and liquid LBE.Our investigations show that it is the delicate balance between the oxide growth and metal dissolution that leads to the observed corrosion anisotropy for bcc Fe contacting with liquid LBE-O.
基金Supported by the National Key Research and Development Program of China(2017YFB0603301)
文摘Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissions in China, it will be necessary to mitigate at least some of these emissions to achieve this goal. Studies by the International Energy Agency(IEA) indicate CCS technology has the potential to contribute 14% of global emission reductions, followed by 40% of higher energy efficiency and 35% of renewable energy, which is considered as the most promising technology to significantly reduce carbon emissions for current coal-fired power plants.Moreover, the announcement of a Chinese national carbon trading market in late 2017 signals an opportunity for the commercial deployment of CO_2 capture technologies.Currently, the only commercially demonstrated technology for post-combustion CO_2 capture technology from power plants is solvent-based absorption. While commercially viable, the costs of deploying this technology are high. This has motivated efforts to develop more affordable alternatives, including advanced solvents, membranes,and sorbent capture systems. Of these approaches, advanced solvents have received the most attention in terms of research and demonstration. In contrast, sorbent capture technology has less attention, despite its potential for much lower energy consumption due to the absence of water in the sorbent. This paper reviews recent progress in the development of sorbent materials modified by amine functionalities with an emphasis on material characterization methods and the effects of operating conditions on performance. The main problems and challenges that need to be overcome to improve the competitiveness of sorbent-based capture technologies are discussed.
文摘Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F intergenic spacer by maximum parsimony and maximum likelihood methods. The results showed that: (a) sect. Stenophora was a strongly supported monophyletic group; (b) D. rockii, D. membranacea, D. banzhuana, and D. simulans formed a moderately supported monophyletic group, and D. prazeri was weakly supported to be sister to this group; (c) D. althaeoides and D. nipponica ssp. nipponica formed a moderately supported clade, and D. nipponica ssp. rosthornii was not a member of this clade; (d) D. zingiberensis and D. sinoparviflora showed a moderate to strong sister relationship; and (e) D. collettii var. hypoglauca and D. collettii var. collettii were sister to each other, but with only weak support.
基金The research was supported by the National Natural Science Foundation of China (Grant No. 41130419, 41240027, 41374061, 41204048) and China Postdoctoral Science Foundation (Grant No. 2012M510533).
基金supported by the National Natural Science Foundation of China (No. 11703016)the Joint Research Fund in Astronomy (No. U1431105) under cooperative agreement between the National Natural Science Foundation of China and the Chinese Academy of Sciences+5 种基金the program of the Light in China’s Western Region (No. 2015-XBQNA-02)the Natural Science Foundation of Shandong Province (Nos. ZR2014AQ019 and JQ201702)the Young Scholars Program of Shandong University, Weihai (Nos. 20820162003 and 20820171006)the program of Tianshan Youth (No. 2017Q091)the Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects (No. OP201704)partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences
文摘By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 UMa manifests a shallow contact configuration, while V509 Cam exhibits a medium contact configuration. Given that both of them are totally eclipsing binaries, the physical parameters derived only by the photometric light curves are reliable. Meanwhile, the period changes of the two targets were analyzed based on all available eclipsing times. We discovered that V342 UMa shows long-term period decrease with a rate of-1.02(±0.54)× 10^-7 d yr^-1 and that V509 Cam displays long-term period increase with a rate of 3.96(±0.90)× 10^-8 d yr^-1. Both the conservative mass transfer and angular momentum loss via magnetic stellar winds can be used to interpret the long-term period decrease of V342 UMa. The longterm period increase of V509 Cam can be explained by mass transfer from the less massive star to the more massive one. The absolute parameters of the two binaries were estimated according to their Gaia distances and our derived photometric solution results. This method can be extended to other contact binaries without radial velocities but with reliable photometric solutions. Their evolutionary states were investigated and we found that they reveal properties that are identical to other W-subtype contact systems.
基金supported by National Natural Science Foundation of China (NSFC) (No. 11703016)by the Joint Research Fund in Astronomy (Nos. U1631108 and U1931103) under cooperative agreement between NSFC and Chinese Academy of Sciences (CAS)+4 种基金by the Natural Science Foundation of Shandong Province (Nos. ZR2014AQ019, ZR2017PA009, ZR2017PA010 and JQ201702)by Young Scholars Program of Shandong University, Weihai (Nos. 20820162003 and 20820171006)by the Chinese Academy of Sciences Interdisciplinary Innovation Teamby the Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects (No. OP201704)partly supported by the Supercomputing Center of Shandong University, Weihai.
文摘The first charge-coupled device photometric light curves in B,V,Rc,and Ic bands of the short-period contact binary star OQ Cam are presented.Through analyzing the light curves with the WilsonDevinney code,it is found that OQ Cam is a W-type shallow contact binary star with a contact degree of f=20.2%.Based on the O-C analyzing,the orbit period displays a long term increasing with a rate of d P/dt=4.40×10^-7 d yr-1.The increasing in orbit period can be interpreted by mass transfer from the less massive component to the more massive one.As the orbit period increases,OQ Cam would evolve from the present shallow contact configuration to a non-contact stage.So it may be a potential candidate to confirm the thermal relaxation oscillation theory.
基金supported by the Joint Research Fund in Astronomy(No.U1931103)under cooperative agreement between the National Natural Science Foundation of China(NSFC)and Chinese Academy of Sciences(CAS)by NSFC(No.11703016)+1 种基金by Young Scholars Program of Shandong University,Weihai(No.20820171006)by the Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects(No.OP201704)。
文摘The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Cep is a median-contact binary(f=33.9(±4.9)%)with a mass ratio of 0.285.It is a W-subtype contact binary,that is,the component with less mass is hotter than the component with more mass,and the light curves are asymmetric(O’Connell effect),which can be explained by the existence of a hot spot on the component with less mass.The orbital inclination is i=88.3°,indicating that it is a totally eclipsing binary,so the parameters obtained are reliable.Through the O-C analyzing,it is found that the orbital period decreases at the rate of P=-3.90(±0.06)×10^(-7)d yr^(-1),which indicates that the mass transfer occurs from the more massive component to the less massive one.
基金the National Natural Science Foundation of China (Grant No. 11873081)partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy, National Astronomical Observatories, CAS。
文摘We conducted photometric and spectroscopic observations of Ross 15 in order to further study the flare properties of this less observed flare star.A total of 28 B-band flares are detected in 128 hr of photometric observations,leading to a total flare rate of 0.22-0.040.04 h-1,more accurate than that provided by previous work.We give the energy range of the B-band flare(1029.5-1031.5 erg) and the flare frequency distribution(FFD) for the star.Within the same energy range,the FFD is lower than that of GJ 1243(M4)and YZ CMi(M4.5),roughly in the middle of those of three M5-type stars and higher than the average FFDs of spectral types> M6.We performed,for the first time for Ross 15,simultaneous high-cadence spectroscopic and photometric observations,resulting in detection of the most energetic flare in our sample.The intensity enhancements of the continuum and Balmer lines with significant correlations between them are detected during the flare,which is the same as those of other deeply studied flare stars with similar spectral type.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11405231 and 91426301
文摘Ti_(3)AlC_(2)samples are irradiated in advance by 3.5 MeV Fe-ion to the fluence of 1.0×10^(16)ion/cm^(2),and then are implanted by 500 keV He-ion with the fluence of 1.0×10^(17)ion/cm^(2)at room temperature.The irradiated samples are investigated by grazing incidence x-ray diffraction(GIXRD)and transmission electron microscopy(TEM).GIXRD results show serious structural distortion,but without amorphization in the irradiated samples.Fe-ion irradiation and He-ion implantation create much more serious structural distortion than single Fe-ion irradiation.TEM results reveal that there are a large number of defect clusters in the damage region,and dense spherical He bubbles appear in the He depositional region.It seems that the pre-damage does not influence the growth of He bubbles,but He-ion implantation influences the pre-created defect configurations.
基金Supported by the National Natural Science Foundation of China under Grant Nos 91426301,11605256 and 11405231
文摘As recombination centers of vacancies(Vs)and self-interstitial atoms(SIAs),firstly grain boundaries(GBs)should have strong capability of trapping point defects.In this study,abilities to trap Vs and SIAs of eight symmetric tilt GBs in tungsten are investigated through first-principles calculations.
基金supported by the National Natural Science Foundation of China(Grant Nos.41888101,41977380 and 42072033)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB26000000 and XDA2004010102)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)the National Social Science Foundation of China(Grant No.21@WTK001)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative Award(Grant No.2018VCA0016)the Je Tsongkhapa Endowment for Central and Inner Asian Archaeology at the University of Arizona。
文摘The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.
基金supported by the National Key Research and Development Project of China(Grant No.2021YFC1523603)the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)+1 种基金the National Natural Science Foundation of China(Grant Nos.42072033&41977380)the National Social Science Foundation of China(Grant Nos.23&ZD268&21@WTK001)。
文摘Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the TP.The timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains controversial.In this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin Lake,on the interior TP.Our analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North China.Using Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 ka.This date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the TP.Taken together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.
基金The authors acknowledge the support from the Natural Science Foundation of China(12264036)the Natural Science Foundation of Inner Mongolia(2021JQ06)+2 种基金Scientific and Technological Development Foundation of the Central Guidance Local(2021ZY0008)Youth Science and Technology Talents Project of Inner Mongolia(NJYT22061)“Light of the West”talent training program of Chinese Academy of Sciences,Talent Development Fund of Inner Mongolia and Grassland Talents of Inner Mongolia.
文摘The anomalous photovoltaic(APV)effect is promising for high-performance ferroelectric materials and devices in photoelectric applications.However,it is a challenge how to tune the APV effect by utilizing the characteristic structure of ferroelectrics.Here,a domain engineering strategy is proposed to enhance the APV effect in lead-free 0.88(Na_(0.5)Bi_(0.5)TiO_(3))-0.12(Ba_(1–1.5x)S_(mx)TiO_(3))(NBT-BST)ferroelectric ceramics.By tuning the domain size based on Sm^(3+)doping,a maximum open-circuit voltage(VOC)of 18.1 V is obtained when Sm^(3+)content is 0.75%,which is much larger than its bandgap(Eg).The mechanism of this large VOC originates from the multiple positive effects induced by the small-size domain,where decreasing domain size enhances ferroelectric polarization and net interface barrier potential,leading to a large driving electric field.Moreover,the APV effect exhibits a giant temperature sensitivity due to the dramatic evolution of small-size domain in the temperature field.This work sheds light on the exploration of ferroelectrics with APV effect and inspires their future high-performance optoelectronic device applications.
基金supported by funds from the National Key Research and Development Program of China(2022YFA0806501)the National Natural Science Foundation of China(81972342 to J.Y.,82173120 to Y.G.,and 82070298 to L.Z.)the Natural Science Basic Research Plan in ShaanxiProvince(2020JZ-29 to J.Y.).
文摘Isocitrate dehydrogenase(IDH)mutations frequently occur in lower-grade gliomas and secondary glioblastomas.Mutant IDHs exhibit a gain-of-function activity,leading to the production of D-2-hydroxyglutarate(D-2HG)by reducing α-ketoglutarate(α-KG),a central player in metabolism and epigenetic modifications.However,the role ofα-KG homeostasis in IDH-mutated gliomagenesis remains elusive.In this study,we found that low expression of oxoglutarate dehydrogenase(OGDH)was a common feature in IDH-mutated gliomas,as well as inastrocytes.This low expression of OGDH resultedin the accumulation of α-KG and promoted astrocyte maturation.However,IDH1 mutation significantly reducedα-KG levels and increased glutaminolysis and DNA/histone methylation in astrocytes.These metabolic and epigenetic alterations inhibited astrocyte maturation and led to cortical dysplasia in mice.Moreover,our results also indicated that reduced OGDH expression can promote the differentiation of glioma cells,while IDH1 mutations impeded the differentiation of glioma cells with low OGDH by reducing the accumulation ofα-KG and increasing glutaminolysis.Finally,we found that l-glutamine increasedα-KG levels and augmented the differentiation-promoting effects of AGI5198,an IDH1-mutant inhibitor,in IDH1-mutant glioma cells.Collectively,this study reveals that low OGDH expression is a crucial metabolic characteristic of IDH-mutant gliomas,providing a potential strategy for the treatment of IDH-mutant gliomas by targetingα-KG homeostasis.