CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA i...CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA interference activity than Cas13a and Cas13c and causes fewer collateral effects than RxCas13d in mammalian cells.However,a programmable CRISPR/Cas13b-mediated RNA interference system for endogenous transcripts in rice has not yet been established.Here,we developed a CRISPR/Cas13b-mediated system to target endogenous transcripts in rice.Our CRISPR/Cas13b system could inhibit multiple endogenous mRNAs simultaneously.In addition,this system efficiently repressed endogenous long noncoding RNAs with more than 50% inhibition in stable transgenic plants.Furthermore,we found only weak collateral effects of the CRISPR/Cas13b-mediated system at the transcriptome-wide level,and no difference in the agronomic traits of stable transgenic rice in the field.We present a programmable CRISPR/Cas13b-mediated knockdown system for rice,offering a potential biotechnological tool for functional genomics and crop improvement.展开更多
This research paper addresses,from an ecogeographic perspective within a localised context,a new concept of nature conservation within modern farming systems:the direct seeding technique based on the principles of the...This research paper addresses,from an ecogeographic perspective within a localised context,a new concept of nature conservation within modern farming systems:the direct seeding technique based on the principles of the Conservation Agriculture System(CAS).The adoption of CAS aims to increase soil fertility,promote biodiversity,and sustain production,making it one of the most effective adaptation solutions available to address the challenges of climate change.CAS is defined as a farming system based on three key principles:minimal soil disturbance(reduced or zero tillage),maintaining a permanent soil cover(with residues from previous crops),and adopting crop rotation(diversifying crops rather than limiting them to a single type in consecutive seasons).However,there is limited research and a lack of scientific studies on the implementation of conservation agriculture in developing nations such as Morocco,particularly in the Had Kourt region.This study aims to assess the feasibility of CAS compared to traditional agricultural systems by surveying the opinions of farmers who have experience with both systems and comparing the outcomes of their practices based on simple indicators as an initial stage,with further analysis of additional indicators planned through subsequent scientific investigations.The sampling method used in this study is non-discriminatory,as semi-structured interviews were conducted with a group of farmers to gather their opinions on CAS.The adoption of conservation agriculture has been linked to prior knowledge of the system,acquired through training and fieldwork via application platforms,which remain limited in scope.展开更多
We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-...We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.展开更多
The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones pr...The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.展开更多
Cenozoic volcanic rocks in the Fildes Peninsula are composed of High-Al basalt, basaltfc andesite, andesite, and dacite belonging to a calc-alkaline volcanic series with low-K and high-Al characteristics. Using a new ...Cenozoic volcanic rocks in the Fildes Peninsula are composed of High-Al basalt, basaltfc andesite, andesite, and dacite belonging to a calc-alkaline volcanic series with low-K and high-Al characteristics. Using a new indicator, the Sr / Ca-Ba / Ca, systematics proposed by Onuma (1980, 1981) and Sr, Ba, Ca concentrations in volcanic lavas and subvolcanic rocks, the authors find that the high-Al basaltic volcanic rocks either in volcanic strata or in subvolcanic intrusives were formed from a primary magma, in different stages through the fractional crystallization of clinopyro-xene(Cpx)and plagioclase (P1) in the process of magmatic evolution, resulting in the formation of basaltic-andesitic, andesitic and dacitic rocks.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LZ22C150002 and LR24C150001)the National Key Research and Development Program of China(Grant Nos.2021YFF1000402 and 2022YFD1401600)+1 种基金the National Natural Science Foundation of China(Grant No.32170262)the Fundamental Research Funds for the Central Universities,China(Grant No.K20240124).
文摘CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA interference activity than Cas13a and Cas13c and causes fewer collateral effects than RxCas13d in mammalian cells.However,a programmable CRISPR/Cas13b-mediated RNA interference system for endogenous transcripts in rice has not yet been established.Here,we developed a CRISPR/Cas13b-mediated system to target endogenous transcripts in rice.Our CRISPR/Cas13b system could inhibit multiple endogenous mRNAs simultaneously.In addition,this system efficiently repressed endogenous long noncoding RNAs with more than 50% inhibition in stable transgenic plants.Furthermore,we found only weak collateral effects of the CRISPR/Cas13b-mediated system at the transcriptome-wide level,and no difference in the agronomic traits of stable transgenic rice in the field.We present a programmable CRISPR/Cas13b-mediated knockdown system for rice,offering a potential biotechnological tool for functional genomics and crop improvement.
文摘This research paper addresses,from an ecogeographic perspective within a localised context,a new concept of nature conservation within modern farming systems:the direct seeding technique based on the principles of the Conservation Agriculture System(CAS).The adoption of CAS aims to increase soil fertility,promote biodiversity,and sustain production,making it one of the most effective adaptation solutions available to address the challenges of climate change.CAS is defined as a farming system based on three key principles:minimal soil disturbance(reduced or zero tillage),maintaining a permanent soil cover(with residues from previous crops),and adopting crop rotation(diversifying crops rather than limiting them to a single type in consecutive seasons).However,there is limited research and a lack of scientific studies on the implementation of conservation agriculture in developing nations such as Morocco,particularly in the Had Kourt region.This study aims to assess the feasibility of CAS compared to traditional agricultural systems by surveying the opinions of farmers who have experience with both systems and comparing the outcomes of their practices based on simple indicators as an initial stage,with further analysis of additional indicators planned through subsequent scientific investigations.The sampling method used in this study is non-discriminatory,as semi-structured interviews were conducted with a group of farmers to gather their opinions on CAS.The adoption of conservation agriculture has been linked to prior knowledge of the system,acquired through training and fieldwork via application platforms,which remain limited in scope.
基金supported in part by the National Key R&D Program of China (Contract Nos.2023YFA1606500,2024YFE0109800,and 2024YFE0110400)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34010000)+5 种基金the Gansu Key Project of Science and Technology (Grant No.23ZDGA014)the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2021B0301030006)the National Natural Science Foundation of China (Grant Nos.12105328,W2412040,12475126,12422507,12035011,12375118,12435008,and W2412043)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-002)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos.2020409 and 2023439)the Russian Science Foundation (Grant No.25-42-00003)。
文摘We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.
基金supported by the National Natural Science Foundation of China (Nos. 52175322, 52271031)the Natural Science Foundation of Jilin Province, China (No. SKL202302015)。
文摘The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.
文摘Cenozoic volcanic rocks in the Fildes Peninsula are composed of High-Al basalt, basaltfc andesite, andesite, and dacite belonging to a calc-alkaline volcanic series with low-K and high-Al characteristics. Using a new indicator, the Sr / Ca-Ba / Ca, systematics proposed by Onuma (1980, 1981) and Sr, Ba, Ca concentrations in volcanic lavas and subvolcanic rocks, the authors find that the high-Al basaltic volcanic rocks either in volcanic strata or in subvolcanic intrusives were formed from a primary magma, in different stages through the fractional crystallization of clinopyro-xene(Cpx)and plagioclase (P1) in the process of magmatic evolution, resulting in the formation of basaltic-andesitic, andesitic and dacitic rocks.
