A set of 132 accessions of commonmillet, Panicum miliaceum L., from12 provinces of China were assessed for endosperm starch type (waxy or non-waxy) using I2-KI staining, amylose and amylopectin contents using the du...A set of 132 accessions of commonmillet, Panicum miliaceum L., from12 provinces of China were assessed for endosperm starch type (waxy or non-waxy) using I2-KI staining, amylose and amylopectin contents using the dual-wavelength colorimetric method, and genotype of Waxygenes conditioning amylose content by gene sequencing. Endosperm starch content varied from 57.69% to 74.70%, while the amylose and amylopectin contents of the starch ranged from 0 to 23.29% and from 41.99% to 70.24%, respectively. Sequencing two Wx genes, including Wx-L (intron 5-exon 7 and intron 8–9) andWx-S (exon 9–intron 10) revealed several polymorphisms (S0, S?15, LC, LF, LY). Marker M5-R11 linking to the Wx-S gene may be used to discriminate waxy common millet accessions from non-waxy ones. Among the 132 accessions, 68 with the S?15 allele had waxy endosperm starch with the amylose content range 0–2.58% and 64 accessions with the S0 allele had non-waxy endosperm starch with amylose content range 3.94%–23.29%. Five genotypes including So15/LF (45% of the accessions), S0/LF (25%), S0/LY (12%), S0/LC (11%), and S?15/LY (7%) were identified. Six new SNPs were detected at the Wx-L locus. These results will facilitate common millet breeding, especially of cultivars free of amylose.展开更多
Metal (Me=Fe(III), Mo(VI), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes (MeHNT) were synthesized and used as mimic-enzyme catalysts to mimic the active group of hor...Metal (Me=Fe(III), Mo(VI), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes (MeHNT) were synthesized and used as mimic-enzyme catalysts to mimic the active group of horseradish peroxidase (HRP). The results showed that Fe-HNT, Mo-HNT are effective catalysts, which have similar catalytic activity as HRP. The sequence of catalytic activities of tested biomimic peroxidas is Mo-HNT > Fe-HNT > Zn-HNT > Ni-HNT > Mn-HNT. Among them, Fe-HNT is used as a mimic-enzyme catalyst in determination of ascorbic acid and glucose by coupling the catalytic reaction of glucose oxidase.展开更多
The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element ...The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element method (HOBEM). In this model, the instantaneous body position and the transient free surface are updated at each time step. A Lagrangian technique is employed as the time marching scheme on the free surface. The mesh regridding and interpolation methods are adopted to deal with the possible numerical instability. Several auxiliary functions are proposed to calculate the wave loads indirectly, instead of directly predicting the temporal derivative of the velocity potential. Numerical experiments are carried out to simulate the heave motions of a submerged sphere in infinite water depth, the heave and pitch motions of a truncated flared cylinder in finite depth. The results are verified against the published numerical results to ensure the effectiveness of the proposed model. Moreover, a series of higher harmonic waves and force components are obtained by the Fourier transformation to investigate the nonlinear effect of oscillation frequency. The difference among fully nonlinear, body-nonlinear and linear results is analyzed. It is found that the nonlinearity due to free surface and body surface has significant influences on the numerical results of the radiated waves and forces.展开更多
Nonlinear wave loads can induce low-frequency and high-frequency resonance motions of a moored platform in deep water. For the analysis of the nonlinear response of an offshore platform under the action of irregular w...Nonlinear wave loads can induce low-frequency and high-frequency resonance motions of a moored platform in deep water. For the analysis of the nonlinear response of an offshore platform under the action of irregular waves, the most widely used method in practice is the Cummins method, in which the second-order exciting forces in the time domain are computed by a two-term Volterra series model based on incident waves, first-order body motion response, and quadratic transfer functions(QTFs). QTFs are bichromatic waves acting on a body and are computed in the frequency domain in advance. For moving bodies, QTFs are related to the first-order body response, which is to be determined in the simulation process of body motion response but is unknown in the computation procedure of QTFs. In solving this problem, Teng and Cong(2017) proposed a method to divide the QTFs into different components,which are unrelated to the body response. With the application of the new QTF components, a modified Cummins method can be developed for the simulation of the nonlinear response of a moored floating platform. This paper presents a review of the theory.展开更多
This paper aims at finding a proper way to estimate sloshing severity.First,the concept of sloshing severity RAO(SSR) is introduced,and the wave elevation on the liquid free surface is chosen as an initial index for t...This paper aims at finding a proper way to estimate sloshing severity.First,the concept of sloshing severity RAO(SSR) is introduced,and the wave elevation on the liquid free surface is chosen as an initial index for the rough prediction of sloshing severity.Then,compared with experimental data from a 3 D regular model test,this index is adjusted and a new index is generated.One step further,sloshing severity under irregular sea states can be achieved by nonlinear combinations of the new index.For validation,the same model tank is tested under a set of irregular sea conditions,and peak pressures and impulse areas are taken as comparison standards.It is found that both numerical and experimental results show a similar tendency of sloshing severity.As a real ship application on the new index,the sloshing severity of a liquefied natural gas floating production storage and offloading(LNG-FPSO) is predicted under a low filling condition.Besides,the ship motion responses with and without sloshing effects are considered for the calculation of severity.From the present observation,this proposed methodology and generated new index is expected to be applicable to the selection of severe sea states for sloshing loads analysis.展开更多
Nutrient boron(B)is important for crop development.The absorption and transport of B ions are regulated by the B transport(BOR)gene family.Although some members of the BOR gene family have been heavily researched,to t...Nutrient boron(B)is important for crop development.The absorption and transport of B ions are regulated by the B transport(BOR)gene family.Although some members of the BOR gene family have been heavily researched,to the best of our knowledge,no comprehensive research on the structural,evolutionary and functional relationships among crops has been reported.In this study,comparative genomic research of the BOR gene family was performed in five crops,40 BOR genes were identified,and analyses of phylogenetics,structure,conserved motifs,and transmembrane topology were performed.These genes had highly similar physicochemical properties,structure and motif distribution.Specific elements in the C-terminus and functional differences were also found among the genes.In addition,microsynteny and evolutionary analysis suggested that large-scale replication events and purifying selection played essential roles during the OsBOR gene evolutionary process in rice.Moreover,expression pattern of OsBORs were also analyzed.Our research provides comprehensive and detailed information on BOR genes in five crops and establishes a foundation for further functional exploration of these genes in B metabolic pathways.展开更多
Great achievements have been made in the exploration of male sterile resources, gene mapping and cloning and molecular mechanism revealing, as well as in breeding and application of two-line rice in China. This paper ...Great achievements have been made in the exploration of male sterile resources, gene mapping and cloning and molecular mechanism revealing, as well as in breeding and application of two-line rice in China. This paper briefly reviewed the discovery, types and cloning of sterile genes in rice and molecular breeding of two-line rice, and summarized the research progress of critical sterility inducing temperature, so as to provide new ideas for the research and breeding of two-line hybrid rice.展开更多
Objective To investigate the efficacy and safety of combined use of clomiphene citrate (CC) and gonadotropins (Gn) on the infertile patients with PCOS. Methods A total of 367 infertile patients with PCOS were incl...Objective To investigate the efficacy and safety of combined use of clomiphene citrate (CC) and gonadotropins (Gn) on the infertile patients with PCOS. Methods A total of 367 infertile patients with PCOS were included in this retrospective study. Patients received CC from menstrual cycle day 3 until the day of triggering and human menopausal gonadotrophins (hMG) from menstrual cycle day 5 until the ovulation day. Gn duration and doses, serum LH and estradiol levels, transferable embryos, incidence of OHSS, frozen-thawed embryo implantation and clinical pregnancy rates were compared among CC plus hMG, long and short protocols. Results Gn duration and doses, blood estrogen level transferable embryos and incidence of OHSS in the group of CC plus hMG were decreased significantly than those of long and short protocols. No differences were observed in the frozen-thawed embryo implantation and clinical pregnancy rates among three groups. Conclusion Mild stimulation of CC combined with hMG on infertile patients with high risk for OHSS is safe and efficient.展开更多
As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation m...As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation may play an important role when the oscillation amplitude of the circular cylinder is large,and large discrepancy will occur between the potential flow simulation and the experimental results.This study focuses on the study of hydrodynamic forces on a submerged horizontal circular cylinder undergoing forced oscillation by means of a viscous fluid numerical wave tank(NWT)model.The accuracy of the numerical model is validated against available experimental data.The comparisons between the hydrodynamic forces on the circular cylinder predicted by the viscous fluid model and the potential flow model are conducted to show the viscous effects on the hydrodynamic forces.By the study on the flow fields,the mechanism of the viscous effects is explained by the vortex effect.The basic reason for the difference between the results based on the viscous fluid theory and the potential flow theory is revealed by analyzing the force components.展开更多
A two-dimensional computational fluid dynamics(CFD)numerical model is developed to study the power takeoff(PTO)efficiency of an Edinburgh duck wave energy converter(WEC)device by using the OpenFOAM source package.Afte...A two-dimensional computational fluid dynamics(CFD)numerical model is developed to study the power takeoff(PTO)efficiency of an Edinburgh duck wave energy converter(WEC)device by using the OpenFOAM source package.After the numerical validations and the convergent verifications,the characteristics of the duck WEC device for the power takeoff in various incident wave periods are examined.The present numerical investigation indicates that the maximum absorbed power of the duck WEC device is attained in its resonant period,while the maximum efficiency is achieved in a lower period.The influence of the damping coefficient on the PTO is also investigated.The optimal damping coefficient for acquiring more power and better efficiency is determined from a numerical examination.展开更多
Biodegradable polymer scaffolds combined with bioactive components which accelerate osteogenesis and angiogenesis have promise for use in clinical bone defect repair.The preclinical acute toxicity evaluation is an ess...Biodegradable polymer scaffolds combined with bioactive components which accelerate osteogenesis and angiogenesis have promise for use in clinical bone defect repair.The preclinical acute toxicity evaluation is an essential assay of implantable biomaterials to assess the biosafety for accelerating clinical translation.We have successfully developed magnesium(Mg)particles and beta-tricalcium phosphate(β-TCP)for incorporation into poly(lactic-co-glycolic acid)(PLGA)porous composite scaffolds(PTM)using low-temperature rapid prototyping three-dimensional-printing technology.The PTM scaffolds have been fully evaluated and found to exhibit excellent osteogenic capacity for bone defect repair.The preclinical evaluation of acute systemic toxicities is essential and important for development of porous scaffolds to facilitate their clinical translation.In this study,acute systemic toxicity of the PTM scaffolds was evaluated in mice by intraperitoneal injection of the extract solutions of the scaffolds.PTM composite scaffolds with different Mg andβ-TCP content(denoted as PT5M,PT10M,and PT15M)were extracted with different tissue culture media,including normal saline,phosphate-buffered saline,and serum-free minimum essential medium,to create the extract solutions.The evaluation was carried out following the National Standard.The acute toxicity was fully evaluated through the collection of extensive data,including serum/organs ion concentration,fluorescence staining,and in vivo median lethal dose measurement.Mg in major organs(heart,liver,and lung),and Mg ion concentrations in serum of mice,after intraperitoneal injection of the extract solutions,were measured and showed that the extract solutions of PT15M caused significant elevation of serum Mg ion concentrations,which exceeded the safety threshold and led to the death of the mice.In contrast,the extract solutions of PT5M and PT10M scaffolds did not cause the death of the injected mice.The median lethal dose of Mg ions in vivo for mice was determined for the first time in this study to be 110.66 mg/kg,and the safety level of serum magnesium toxicity in mice is 5.4 mM,while the calcium serum safety level is determined as 3.4 mM.The study was approved by the Animal Care and Use Committee of Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences(approval No.SIAT-IRB-170401-YGS-LYX-A0346)on April 5,2017.All these results showed that the Mg ion concentration of intraperitoneally-injected extract solutions was a determinant of mouse survival,and a high Mg ion concentration(more than 240 mM)was the pivotal factor contributing to the death of the mice,while changes in pH value showed a negligible effect.The comprehensive acute systemic toxicity evaluation for PTM porous composite scaffolds in this study provided a reference to guide the design and optimization of this composite scaffold and the results demonstrated the preclinical safety of the as-fabricated PTM scaffold with appropriate Mg content,strongly supporting the official registration process of the PTM scaffold as a medical device for clinical translation.展开更多
The Thirty-Second Workshop on Water Waves and Floating Bodies was held in Dalian from April23-26,2017,and hosted by State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology(DUT).IWWWF...The Thirty-Second Workshop on Water Waves and Floating Bodies was held in Dalian from April23-26,2017,and hosted by State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology(DUT).IWWWFB2017 attracts over90 participants from 17 countries,in which 65participants from abroad.展开更多
基金supported by the National Natural Science Foundation of China(31271791)Research Project supported by Shanxi Scholarship Council of China(2016-066)+4 种基金the Subject Construction Project of Anhui Academy of Agricultural Sciences(16A0102)China Agriculture Research System(CARS-06-13.5-A16)the Key Research and Development Program(General Project)(Agriculture)of Shanxi Province of China(201603D221003-5)the Special Program of Crop Germplasm Resources Protection and Utilization of Ministry of Agriculture of the People's Republic of China(2017NWB036-21)the Subplatform Project of National Proso Millet Germplasm Resources of China(NICGR2017-027)
文摘A set of 132 accessions of commonmillet, Panicum miliaceum L., from12 provinces of China were assessed for endosperm starch type (waxy or non-waxy) using I2-KI staining, amylose and amylopectin contents using the dual-wavelength colorimetric method, and genotype of Waxygenes conditioning amylose content by gene sequencing. Endosperm starch content varied from 57.69% to 74.70%, while the amylose and amylopectin contents of the starch ranged from 0 to 23.29% and from 41.99% to 70.24%, respectively. Sequencing two Wx genes, including Wx-L (intron 5-exon 7 and intron 8–9) andWx-S (exon 9–intron 10) revealed several polymorphisms (S0, S?15, LC, LF, LY). Marker M5-R11 linking to the Wx-S gene may be used to discriminate waxy common millet accessions from non-waxy ones. Among the 132 accessions, 68 with the S?15 allele had waxy endosperm starch with the amylose content range 0–2.58% and 64 accessions with the S0 allele had non-waxy endosperm starch with amylose content range 3.94%–23.29%. Five genotypes including So15/LF (45% of the accessions), S0/LF (25%), S0/LY (12%), S0/LC (11%), and S?15/LY (7%) were identified. Six new SNPs were detected at the Wx-L locus. These results will facilitate common millet breeding, especially of cultivars free of amylose.
文摘Metal (Me=Fe(III), Mo(VI), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes (MeHNT) were synthesized and used as mimic-enzyme catalysts to mimic the active group of horseradish peroxidase (HRP). The results showed that Fe-HNT, Mo-HNT are effective catalysts, which have similar catalytic activity as HRP. The sequence of catalytic activities of tested biomimic peroxidas is Mo-HNT > Fe-HNT > Zn-HNT > Ni-HNT > Mn-HNT. Among them, Fe-HNT is used as a mimic-enzyme catalyst in determination of ascorbic acid and glucose by coupling the catalytic reaction of glucose oxidase.
基金supported by the National Natural Science Foundation of China(51222902,51221961,and 51379032)the Program for New Century Excellent Talents in University(NCET-130076)+2 种基金The Fundamental Research Fund for the Central University(HEUCF140103)The Open Fund of State Key Laboratory of Coastal and Offshore Engineering(LP1407)the Lloyd’s Register Foundation (LRF) through the Joint Centre Involving University College London,Shanghai Jiaotong University and Harbin Engineering University
文摘The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element method (HOBEM). In this model, the instantaneous body position and the transient free surface are updated at each time step. A Lagrangian technique is employed as the time marching scheme on the free surface. The mesh regridding and interpolation methods are adopted to deal with the possible numerical instability. Several auxiliary functions are proposed to calculate the wave loads indirectly, instead of directly predicting the temporal derivative of the velocity potential. Numerical experiments are carried out to simulate the heave motions of a submerged sphere in infinite water depth, the heave and pitch motions of a truncated flared cylinder in finite depth. The results are verified against the published numerical results to ensure the effectiveness of the proposed model. Moreover, a series of higher harmonic waves and force components are obtained by the Fourier transformation to investigate the nonlinear effect of oscillation frequency. The difference among fully nonlinear, body-nonlinear and linear results is analyzed. It is found that the nonlinearity due to free surface and body surface has significant influences on the numerical results of the radiated waves and forces.
基金the National Key R&D Program of China (Grant No.2016YFE0200100)the National Natural Science Foundation of China (Grant Nos.51490672 and 51479026).
文摘Nonlinear wave loads can induce low-frequency and high-frequency resonance motions of a moored platform in deep water. For the analysis of the nonlinear response of an offshore platform under the action of irregular waves, the most widely used method in practice is the Cummins method, in which the second-order exciting forces in the time domain are computed by a two-term Volterra series model based on incident waves, first-order body motion response, and quadratic transfer functions(QTFs). QTFs are bichromatic waves acting on a body and are computed in the frequency domain in advance. For moving bodies, QTFs are related to the first-order body response, which is to be determined in the simulation process of body motion response but is unknown in the computation procedure of QTFs. In solving this problem, Teng and Cong(2017) proposed a method to divide the QTFs into different components,which are unrelated to the body response. With the application of the new QTF components, a modified Cummins method can be developed for the simulation of the nonlinear response of a moored floating platform. This paper presents a review of the theory.
文摘This paper aims at finding a proper way to estimate sloshing severity.First,the concept of sloshing severity RAO(SSR) is introduced,and the wave elevation on the liquid free surface is chosen as an initial index for the rough prediction of sloshing severity.Then,compared with experimental data from a 3 D regular model test,this index is adjusted and a new index is generated.One step further,sloshing severity under irregular sea states can be achieved by nonlinear combinations of the new index.For validation,the same model tank is tested under a set of irregular sea conditions,and peak pressures and impulse areas are taken as comparison standards.It is found that both numerical and experimental results show a similar tendency of sloshing severity.As a real ship application on the new index,the sloshing severity of a liquefied natural gas floating production storage and offloading(LNG-FPSO) is predicted under a low filling condition.Besides,the ship motion responses with and without sloshing effects are considered for the calculation of severity.From the present observation,this proposed methodology and generated new index is expected to be applicable to the selection of severe sea states for sloshing loads analysis.
基金National Science Foundation of Anhui Province(grant number 1908085QC135)Anhui Science and Technology Department,International Science&Technology Cooperation Plan(grant number 1804b06020344)+1 种基金Anhui Science and Technology DepartmentMajor Science and Technology Projects(grant number 201903a06020012).
文摘Nutrient boron(B)is important for crop development.The absorption and transport of B ions are regulated by the B transport(BOR)gene family.Although some members of the BOR gene family have been heavily researched,to the best of our knowledge,no comprehensive research on the structural,evolutionary and functional relationships among crops has been reported.In this study,comparative genomic research of the BOR gene family was performed in five crops,40 BOR genes were identified,and analyses of phylogenetics,structure,conserved motifs,and transmembrane topology were performed.These genes had highly similar physicochemical properties,structure and motif distribution.Specific elements in the C-terminus and functional differences were also found among the genes.In addition,microsynteny and evolutionary analysis suggested that large-scale replication events and purifying selection played essential roles during the OsBOR gene evolutionary process in rice.Moreover,expression pattern of OsBORs were also analyzed.Our research provides comprehensive and detailed information on BOR genes in five crops and establishes a foundation for further functional exploration of these genes in B metabolic pathways.
基金Supported by Open Project of State Key Laboratory of Rice Biology(160103)Key Technologies R&D Program of Anhui Province(1804b06020344)
文摘Great achievements have been made in the exploration of male sterile resources, gene mapping and cloning and molecular mechanism revealing, as well as in breeding and application of two-line rice in China. This paper briefly reviewed the discovery, types and cloning of sterile genes in rice and molecular breeding of two-line rice, and summarized the research progress of critical sterility inducing temperature, so as to provide new ideas for the research and breeding of two-line hybrid rice.
文摘Objective To investigate the efficacy and safety of combined use of clomiphene citrate (CC) and gonadotropins (Gn) on the infertile patients with PCOS. Methods A total of 367 infertile patients with PCOS were included in this retrospective study. Patients received CC from menstrual cycle day 3 until the day of triggering and human menopausal gonadotrophins (hMG) from menstrual cycle day 5 until the ovulation day. Gn duration and doses, serum LH and estradiol levels, transferable embryos, incidence of OHSS, frozen-thawed embryo implantation and clinical pregnancy rates were compared among CC plus hMG, long and short protocols. Results Gn duration and doses, blood estrogen level transferable embryos and incidence of OHSS in the group of CC plus hMG were decreased significantly than those of long and short protocols. No differences were observed in the frozen-thawed embryo implantation and clinical pregnancy rates among three groups. Conclusion Mild stimulation of CC combined with hMG on infertile patients with high risk for OHSS is safe and efficient.
基金Project supported by the Natural Science Foundation of China(Grant Nos.51490672,51761135011,51679036 and 51709038).
文摘As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation may play an important role when the oscillation amplitude of the circular cylinder is large,and large discrepancy will occur between the potential flow simulation and the experimental results.This study focuses on the study of hydrodynamic forces on a submerged horizontal circular cylinder undergoing forced oscillation by means of a viscous fluid numerical wave tank(NWT)model.The accuracy of the numerical model is validated against available experimental data.The comparisons between the hydrodynamic forces on the circular cylinder predicted by the viscous fluid model and the potential flow model are conducted to show the viscous effects on the hydrodynamic forces.By the study on the flow fields,the mechanism of the viscous effects is explained by the vortex effect.The basic reason for the difference between the results based on the viscous fluid theory and the potential flow theory is revealed by analyzing the force components.
基金the National Natural Science Foundation of China(Grant Nos.51490672,51879039).
文摘A two-dimensional computational fluid dynamics(CFD)numerical model is developed to study the power takeoff(PTO)efficiency of an Edinburgh duck wave energy converter(WEC)device by using the OpenFOAM source package.After the numerical validations and the convergent verifications,the characteristics of the duck WEC device for the power takeoff in various incident wave periods are examined.The present numerical investigation indicates that the maximum absorbed power of the duck WEC device is attained in its resonant period,while the maximum efficiency is achieved in a lower period.The influence of the damping coefficient on the PTO is also investigated.The optimal damping coefficient for acquiring more power and better efficiency is determined from a numerical examination.
基金supported by the National Natural Science Foundation of China(Nos.82022045&22007098)Chinese Academy of Sciences(CAS)Interdisciplinary Innovation Team(No.JCTD-2020-19)+4 种基金Shenzhen Double Chain Project for Innovation and Development Industry supported by Bureau of Industry and Information Technology of Shenzhen of China(No.201806081503414910)Shenzhen Fundamental Research Foundation of China(No.JCYJ20190807154807663)Key Laboratory of Health Informatics,Chinese Academy of Sciences,Chinese Academic of Sciences-Hong Kong(CAS-HK)Joint Lab of Biomaterials and Natural Science Foundation of Guangdong Province of China(No.2018A030310670)Shenzhen Engineering Research Centre for Medical Bioactive Materials of China(No.XMHT20190106001)Shenzhen Institute of Advanced Technology(SIAT)Innovation Program for Excellent Young Researchers of China(No.2020001345).
文摘Biodegradable polymer scaffolds combined with bioactive components which accelerate osteogenesis and angiogenesis have promise for use in clinical bone defect repair.The preclinical acute toxicity evaluation is an essential assay of implantable biomaterials to assess the biosafety for accelerating clinical translation.We have successfully developed magnesium(Mg)particles and beta-tricalcium phosphate(β-TCP)for incorporation into poly(lactic-co-glycolic acid)(PLGA)porous composite scaffolds(PTM)using low-temperature rapid prototyping three-dimensional-printing technology.The PTM scaffolds have been fully evaluated and found to exhibit excellent osteogenic capacity for bone defect repair.The preclinical evaluation of acute systemic toxicities is essential and important for development of porous scaffolds to facilitate their clinical translation.In this study,acute systemic toxicity of the PTM scaffolds was evaluated in mice by intraperitoneal injection of the extract solutions of the scaffolds.PTM composite scaffolds with different Mg andβ-TCP content(denoted as PT5M,PT10M,and PT15M)were extracted with different tissue culture media,including normal saline,phosphate-buffered saline,and serum-free minimum essential medium,to create the extract solutions.The evaluation was carried out following the National Standard.The acute toxicity was fully evaluated through the collection of extensive data,including serum/organs ion concentration,fluorescence staining,and in vivo median lethal dose measurement.Mg in major organs(heart,liver,and lung),and Mg ion concentrations in serum of mice,after intraperitoneal injection of the extract solutions,were measured and showed that the extract solutions of PT15M caused significant elevation of serum Mg ion concentrations,which exceeded the safety threshold and led to the death of the mice.In contrast,the extract solutions of PT5M and PT10M scaffolds did not cause the death of the injected mice.The median lethal dose of Mg ions in vivo for mice was determined for the first time in this study to be 110.66 mg/kg,and the safety level of serum magnesium toxicity in mice is 5.4 mM,while the calcium serum safety level is determined as 3.4 mM.The study was approved by the Animal Care and Use Committee of Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences(approval No.SIAT-IRB-170401-YGS-LYX-A0346)on April 5,2017.All these results showed that the Mg ion concentration of intraperitoneally-injected extract solutions was a determinant of mouse survival,and a high Mg ion concentration(more than 240 mM)was the pivotal factor contributing to the death of the mice,while changes in pH value showed a negligible effect.The comprehensive acute systemic toxicity evaluation for PTM porous composite scaffolds in this study provided a reference to guide the design and optimization of this composite scaffold and the results demonstrated the preclinical safety of the as-fabricated PTM scaffold with appropriate Mg content,strongly supporting the official registration process of the PTM scaffold as a medical device for clinical translation.
文摘The Thirty-Second Workshop on Water Waves and Floating Bodies was held in Dalian from April23-26,2017,and hosted by State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology(DUT).IWWWFB2017 attracts over90 participants from 17 countries,in which 65participants from abroad.