The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully ci...The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.展开更多
It is well-known that grain refiners can tailor the microstructure and enhance the mechanical properties of titanium alloys fabricated by additive manufacturing(AM). However, the intrinsic mechanisms of Ni addition on...It is well-known that grain refiners can tailor the microstructure and enhance the mechanical properties of titanium alloys fabricated by additive manufacturing(AM). However, the intrinsic mechanisms of Ni addition on AM-built Ti–6Al–4V alloy is not well established. This limits its industrial applications. This work systematically investigated the influence of Ni additive on Ti–6Al–4V alloy fabricated by laser aided additive manufacturing(LAAM). The results showed that Ni addition yields three key effects on the microstructural evolution of LAAM-built Ti–6Al–4V alloy.(a) Ni additive remarkably refines the prior-β grains, which is due to the widened solidification range. As the Ni addition increased from 0 to 2.5 wt. %, the major-axis length and aspect ratio of the prior-β grains reduced from over 1500 μm and 7 to 97.7 μm and1.46, respectively.(b) Ni additive can discernibly induce the formation of globular α phase,which is attributed to the enhanced concentration gradient between the β and α phases. This is the driving force of globularization according to the termination mass transfer theory. The aspect ratio of the α laths decreased from 4.14 to 2.79 as the Ni addition increased from 0 to2.5 wt. %.(c) Ni as a well-known β-stabilizer and it can remarkably increase the volume fraction of β phase. Room-temperature tensile results demonstrated an increase in mechanical strength and an almost linearly decreasing elongation with increasing Ni addition. A modified mathematical model was used to quantitatively analyze the strengthening mechanism. It was evident from the results that the α lath phase and the solid solutes contribute the most to the overall yield strength of the LAAM-built Ti–6Al–4V–x Ni alloys in this work. Furthermore, the decrease in elongation with increasing Ni addition is due to the deterioration in deformability of the β phase caused by a large amount of solid-solution Ni atoms. These findings can accelerate the development of additively manufactured titanium alloys.展开更多
Since its initial release in 2001,the human reference genome has undergone continuous improvement in quality,and the recently released telomere-to-telomere(T2T)version-T2T-CHM13—reaches its highest level of continuit...Since its initial release in 2001,the human reference genome has undergone continuous improvement in quality,and the recently released telomere-to-telomere(T2T)version-T2T-CHM13—reaches its highest level of continuity and accuracy after 20 years of effort by working on a simplified,nearly homozygous genome of a hydatidiform mole cell line.Here,to provide an authentic complete diploid human genome reference for the Han Chinese,the largest population in the world,we assembled the genome of a male Han Chinese individual,T2T-YAO,which includes T2T assemblies of all the 22+X+M and 22+Y chromosomes in both haploids.The quality of T2T-YAO is much better than those of all currently available diploid assemblies,and its haploid version,T2T-YAO-hp,generated by selecting the better assembly for each autosome,reaches the top quality of fewer than one error per 29.5 Mb,even higher than that of T2T-CHM13.Derived from an individual living in the aboriginal region of the Han population,T2T-YAO shows clear ancestry and potential genetic continuity from the ancient ancestors.Each haplotype of T2TYAO possesses330-Mb exclusive sequences,3100 unique genes,and tens of thousands of nucleotide and structural variations as compared with CHM13,highlighting the necessity of a population-stratified reference genome.The construction of T2T-YAO,an accurate and authentic representative of the Chinese population,would enable precise delineation of genomic variations and advance our understandings in the hereditability of diseases and phenotypes,especially within the context of the unique variations of the Chinese population.展开更多
Hydrogen-bonded capsules have been widely employed as supramolecular hosts for organic molecular guests.Encapsulation of fullerenes by capsules is relatively scarce,especially those that utilize sulfur atoms as hydrog...Hydrogen-bonded capsules have been widely employed as supramolecular hosts for organic molecular guests.Encapsulation of fullerenes by capsules is relatively scarce,especially those that utilize sulfur atoms as hydrogen-bond acceptors.Herein,we describe,in both solution and solid state,a bowl-shaped nanobelt[8]cyclophenoxathiin 1a and its tetra-methylated derivative 1b that can form C–H⋯S hydrogen-bonded capsules induced by complexation with suitable fullerenes.1a strongly encapsulates C60,C70,or 6,6-phenyl-C61-butyric acid methyl ester(PC61BM)to form a 2∶1 ternary complex featuring 16 equatorial(sp2)C–H⋯S hydrogen bonds.A pseudorotaxane structure was further obtained for the complex of 1a with PC61BM.Conversely,a 1∶1 inclusion complex was observed for binding C60 or PC61BM with 1b indicating the reduced tendency to form capsules by introducing methyl groups into the belt.Surprisingly,the capsule-like structure was retained for the 1:2 complex of C70 with 1b as observed by the presence of multiple(sp3)C–H⋯S hydrogen bonds.The strong binding affinity and tailorable complexation mode enable further applications of nanobelts in fullerene chemistry.展开更多
To unravel the genetic mechanisms of disease and physiological traits,it requires comprehensive sequencing analysis of large sample size in Chinese populations.Here,we report the primary results of the Chinese Academy...To unravel the genetic mechanisms of disease and physiological traits,it requires comprehensive sequencing analysis of large sample size in Chinese populations.Here,we report the primary results of the Chinese Academy of Sciences Precision Medicine Initiative(CASPMI)project launched by the Chinese Academy of Sciences,including the de novo assembly of a northern Han reference genome(NH1.0)and whole genome analyses of 597 healthy people coming from most areas in China.Given the two existing reference genomes for Han Chinese(YH and HX1)were both from the south,we constructed NH1.0,a new reference genome from a northern individual,by combining the sequencing strategies of PacBio,10×Genomics,and Bionano mapping.Using this integrated approach,we obtained an N50 scaffold size of 46.63 Mb for the NH1.0 genome and performed a comparative genome analysis of NH1.0 with YH and HX1.In order to generate a genomic variation map of Chinese populations,we performed the whole-genome sequencing of 597 participants and identified 24.85 million(M)single nucleotide variants(SNVs),3.85 M small indels,and 106,382 structural variations.In the association analysis with collected phenotypes,we found that the T allele of rs1549293 in KAT8 significantly correlated with the waist circumference in northern Han males.Moreover,significant genetic diversity in MTHFR,TCN2,FADS1,and FADS2,which associate with circulating folate,vitamin B12,or lipid metabolism,was observed between northerners and southerners.Especially,for the homocysteine-increasing allele of rs1801133(MTHFR 677T),we hypothesize that there exists a “comfort”zone for a high frequency of 677T between latitudes of 35–45 degree North.Taken together,our results provide a high-quality northern Han reference genome and novel population-specific data sets of genetic variants for use in the personalized and precision medicine.展开更多
On January 22,2020,China National Center for Bioinformation(CNCB)released the 2019 Novel Coronavirus Resource(2019nCoVR),an open-access information resource for the severe acute respiratory syndrome coronavirus 2(SARS...On January 22,2020,China National Center for Bioinformation(CNCB)released the 2019 Novel Coronavirus Resource(2019nCoVR),an open-access information resource for the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).2019nCoVR features a comprehensive integration of sequence and clinical information for all publicly available SARS-CoV-2 isolates,which are manually curated with value-added annotations and quality evaluated by an automated in-house pipeline.Of particular note,2019nCoVR offers systematic analyses to generate a dynamic landscape of SARS-CoV-2 genomic variations at a global scale.It provides all identified variants and their detailed statistics for each virus isolate,and congregates the quality score,functional annotation,and population frequency for each variant.Spatiotemporal change for each variant can be visualized and historical viral haplotype network maps for the course of the outbreak are also generated based on all complete and high-quality genomes available.Moreover,2019nCoVR provides a full collection of SARS-CoV-2 relevant literature on the coronavirus disease 2019(COVID-19),including published papers from PubMed as well as preprints from services such as bioRxiv and medRxiv through Europe PMC.Furthermore,by linking with relevant databases in CNCB,2019nCoVR offers data submission services for raw sequence reads and assembled genomes,and data sharing with NCBI.Collectively,SARS-CoV-2 is updated daily to collect the latest information on genome sequences,variants,haplotypes,and literature for a timely reflection,making 2019nCoVR a valuable resource for the global research community.2019nCoVR is accessible at https://bigd.big.ac.cn/ncov/.展开更多
By re-analzying public metagenomic data from 101 patients infected with influenza A virus during the 2007–2012 H1N1 flu seasons in France,we identified 22 samples with SARS-CoV sequences.In three of them,the SARS gen...By re-analzying public metagenomic data from 101 patients infected with influenza A virus during the 2007–2012 H1N1 flu seasons in France,we identified 22 samples with SARS-CoV sequences.In three of them,the SARS genome sequences could be fully assembled out of each.These sequences are highly similar(99.99%and 99.70%)to the artificially constructed recombinant SARS-CoV(SARSr-CoV)strains generated by the J.Craig Venter Institute in the USA.Moreover,samples from different flu seasons have different SARS-CoV strains,and the divergence between these strains cannot be explained by natural evolution.Our study also shows that retrospective studies using public metagenomic data from past major epidemic outbreaks serve as a genomic strategy for the research of the origins or spread of infectious diseases.展开更多
基金financially supported by the Agency for Science,Technology and Research(A*Star),Republic of Singapore,under the Aerospace Consortium Cycle 12“Characterization of the Effect of Wire and Powder Deposited Materials”(No.A1815a0078)。
文摘The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.
基金supported by the Agency for Science,Technology and Research(A*Star),Republic of Singapore under the IAF-PP program‘Integrated large format hybrid manufacturing using wire-fed and powder-blown technology for LAAM process’,Grant No.A1893a0031the Academy of Sciences Project of Guangdong Province,Grant No.2016GDASRC-0105。
文摘It is well-known that grain refiners can tailor the microstructure and enhance the mechanical properties of titanium alloys fabricated by additive manufacturing(AM). However, the intrinsic mechanisms of Ni addition on AM-built Ti–6Al–4V alloy is not well established. This limits its industrial applications. This work systematically investigated the influence of Ni additive on Ti–6Al–4V alloy fabricated by laser aided additive manufacturing(LAAM). The results showed that Ni addition yields three key effects on the microstructural evolution of LAAM-built Ti–6Al–4V alloy.(a) Ni additive remarkably refines the prior-β grains, which is due to the widened solidification range. As the Ni addition increased from 0 to 2.5 wt. %, the major-axis length and aspect ratio of the prior-β grains reduced from over 1500 μm and 7 to 97.7 μm and1.46, respectively.(b) Ni additive can discernibly induce the formation of globular α phase,which is attributed to the enhanced concentration gradient between the β and α phases. This is the driving force of globularization according to the termination mass transfer theory. The aspect ratio of the α laths decreased from 4.14 to 2.79 as the Ni addition increased from 0 to2.5 wt. %.(c) Ni as a well-known β-stabilizer and it can remarkably increase the volume fraction of β phase. Room-temperature tensile results demonstrated an increase in mechanical strength and an almost linearly decreasing elongation with increasing Ni addition. A modified mathematical model was used to quantitatively analyze the strengthening mechanism. It was evident from the results that the α lath phase and the solid solutes contribute the most to the overall yield strength of the LAAM-built Ti–6Al–4V–x Ni alloys in this work. Furthermore, the decrease in elongation with increasing Ni addition is due to the deterioration in deformability of the β phase caused by a large amount of solid-solution Ni atoms. These findings can accelerate the development of additively manufactured titanium alloys.
基金supported by the Science and Technology Research Project of Henan(Grant No.232102311003)the National Natural Science Foundation of China(Grant No.U1804282)。
文摘Since its initial release in 2001,the human reference genome has undergone continuous improvement in quality,and the recently released telomere-to-telomere(T2T)version-T2T-CHM13—reaches its highest level of continuity and accuracy after 20 years of effort by working on a simplified,nearly homozygous genome of a hydatidiform mole cell line.Here,to provide an authentic complete diploid human genome reference for the Han Chinese,the largest population in the world,we assembled the genome of a male Han Chinese individual,T2T-YAO,which includes T2T assemblies of all the 22+X+M and 22+Y chromosomes in both haploids.The quality of T2T-YAO is much better than those of all currently available diploid assemblies,and its haploid version,T2T-YAO-hp,generated by selecting the better assembly for each autosome,reaches the top quality of fewer than one error per 29.5 Mb,even higher than that of T2T-CHM13.Derived from an individual living in the aboriginal region of the Han population,T2T-YAO shows clear ancestry and potential genetic continuity from the ancient ancestors.Each haplotype of T2TYAO possesses330-Mb exclusive sequences,3100 unique genes,and tens of thousands of nucleotide and structural variations as compared with CHM13,highlighting the necessity of a population-stratified reference genome.The construction of T2T-YAO,an accurate and authentic representative of the Chinese population,would enable precise delineation of genomic variations and advance our understandings in the hereditability of diseases and phenotypes,especially within the context of the unique variations of the Chinese population.
基金the National Natural Science Foundation of China(grant nos.21971268 and 22171295)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(grant no.2017ZT07C069)+1 种基金Pearl River Talent Program(grant no.2017GC010623)the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(grant no.SN-ZJU-SIAS-006)for financial support.
文摘Hydrogen-bonded capsules have been widely employed as supramolecular hosts for organic molecular guests.Encapsulation of fullerenes by capsules is relatively scarce,especially those that utilize sulfur atoms as hydrogen-bond acceptors.Herein,we describe,in both solution and solid state,a bowl-shaped nanobelt[8]cyclophenoxathiin 1a and its tetra-methylated derivative 1b that can form C–H⋯S hydrogen-bonded capsules induced by complexation with suitable fullerenes.1a strongly encapsulates C60,C70,or 6,6-phenyl-C61-butyric acid methyl ester(PC61BM)to form a 2∶1 ternary complex featuring 16 equatorial(sp2)C–H⋯S hydrogen bonds.A pseudorotaxane structure was further obtained for the complex of 1a with PC61BM.Conversely,a 1∶1 inclusion complex was observed for binding C60 or PC61BM with 1b indicating the reduced tendency to form capsules by introducing methyl groups into the belt.Surprisingly,the capsule-like structure was retained for the 1:2 complex of C70 with 1b as observed by the presence of multiple(sp3)C–H⋯S hydrogen bonds.The strong binding affinity and tailorable complexation mode enable further applications of nanobelts in fullerene chemistry.
基金supported by the grants of Key Program of the Chinese Academy of Sciences(Grant No.KJZD-EW-L14 awarded to CZ)the National Key R&D Program of China from the Ministry of Science and Technology of China(Grant No.2016YFB0201702 awarded to JX,as well as Grant Nos.2016YFC0901701 and 2018YFC0910700 awarded to XF)
文摘To unravel the genetic mechanisms of disease and physiological traits,it requires comprehensive sequencing analysis of large sample size in Chinese populations.Here,we report the primary results of the Chinese Academy of Sciences Precision Medicine Initiative(CASPMI)project launched by the Chinese Academy of Sciences,including the de novo assembly of a northern Han reference genome(NH1.0)and whole genome analyses of 597 healthy people coming from most areas in China.Given the two existing reference genomes for Han Chinese(YH and HX1)were both from the south,we constructed NH1.0,a new reference genome from a northern individual,by combining the sequencing strategies of PacBio,10×Genomics,and Bionano mapping.Using this integrated approach,we obtained an N50 scaffold size of 46.63 Mb for the NH1.0 genome and performed a comparative genome analysis of NH1.0 with YH and HX1.In order to generate a genomic variation map of Chinese populations,we performed the whole-genome sequencing of 597 participants and identified 24.85 million(M)single nucleotide variants(SNVs),3.85 M small indels,and 106,382 structural variations.In the association analysis with collected phenotypes,we found that the T allele of rs1549293 in KAT8 significantly correlated with the waist circumference in northern Han males.Moreover,significant genetic diversity in MTHFR,TCN2,FADS1,and FADS2,which associate with circulating folate,vitamin B12,or lipid metabolism,was observed between northerners and southerners.Especially,for the homocysteine-increasing allele of rs1801133(MTHFR 677T),we hypothesize that there exists a “comfort”zone for a high frequency of 677T between latitudes of 35–45 degree North.Taken together,our results provide a high-quality northern Han reference genome and novel population-specific data sets of genetic variants for use in the personalized and precision medicine.
基金This work was supported by grants from the Strategic PriorityResearch Program of Chinese Academy of Sciences(GrantNos.XDA19090116,XDA19050302,and XDB38030400)awarded to SS,ZZ,and MLthe National Key R&D Programof China(Grant Nos.2020YFC0848900,2020YFC0847000,2016YFE0206600,and 2017YFC0907502)+5 种基金the 13th Five-yearInformatization Plan of Chinese Academy of Sciences(GrantNo.XXH13505-05)Genomics Data Center Construction ofChinese Academy of Sciences(Grant No.XXH-13514-0202)the Open Biodiversity and Health Big Data Programme ofInternational Union of Biological Sciences,International Part-nership Program of Chinese Academy of Sciences(Grant No.153F11KYSB20160008)the Professional Association of theAlliance of International Science Organizations(Grant No.ANSO-PA-2020-07)This work was also supported by KCWong Education Foundation to ZZthe YouthInnovation Promotion Association of Chinese Academy ofSciences(Grant Nos.2017141 and 2019104)awarded to SSand ML.
文摘On January 22,2020,China National Center for Bioinformation(CNCB)released the 2019 Novel Coronavirus Resource(2019nCoVR),an open-access information resource for the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).2019nCoVR features a comprehensive integration of sequence and clinical information for all publicly available SARS-CoV-2 isolates,which are manually curated with value-added annotations and quality evaluated by an automated in-house pipeline.Of particular note,2019nCoVR offers systematic analyses to generate a dynamic landscape of SARS-CoV-2 genomic variations at a global scale.It provides all identified variants and their detailed statistics for each virus isolate,and congregates the quality score,functional annotation,and population frequency for each variant.Spatiotemporal change for each variant can be visualized and historical viral haplotype network maps for the course of the outbreak are also generated based on all complete and high-quality genomes available.Moreover,2019nCoVR provides a full collection of SARS-CoV-2 relevant literature on the coronavirus disease 2019(COVID-19),including published papers from PubMed as well as preprints from services such as bioRxiv and medRxiv through Europe PMC.Furthermore,by linking with relevant databases in CNCB,2019nCoVR offers data submission services for raw sequence reads and assembled genomes,and data sharing with NCBI.Collectively,SARS-CoV-2 is updated daily to collect the latest information on genome sequences,variants,haplotypes,and literature for a timely reflection,making 2019nCoVR a valuable resource for the global research community.2019nCoVR is accessible at https://bigd.big.ac.cn/ncov/.
基金supported by the National Key R&D Program of China(2021YFC0863400)the Key Program of Chinese Academy of Sciences(KJZD-SW-L14)the National Natural Science Foundation of China(Grant No.31571370 and 91731302).
文摘By re-analzying public metagenomic data from 101 patients infected with influenza A virus during the 2007–2012 H1N1 flu seasons in France,we identified 22 samples with SARS-CoV sequences.In three of them,the SARS genome sequences could be fully assembled out of each.These sequences are highly similar(99.99%and 99.70%)to the artificially constructed recombinant SARS-CoV(SARSr-CoV)strains generated by the J.Craig Venter Institute in the USA.Moreover,samples from different flu seasons have different SARS-CoV strains,and the divergence between these strains cannot be explained by natural evolution.Our study also shows that retrospective studies using public metagenomic data from past major epidemic outbreaks serve as a genomic strategy for the research of the origins or spread of infectious diseases.