Bio-inspired porous metallic scaffolds have tremendous potential to be used as artificial bone substitutes.In this work,a radially graded lattice structure (RGLS),which mimics the structures of natural human bones,was...Bio-inspired porous metallic scaffolds have tremendous potential to be used as artificial bone substitutes.In this work,a radially graded lattice structure (RGLS),which mimics the structures of natural human bones,was designed and processed by laser powder bed fusion of martensitic Ti-rich TiNi powder.The asymmetric tension-compression behaviour,where the compressive strength is significantly higher than the tensile strength,is observed in this Ti-rich TiNi material,which echoes the mechanical behaviour of bones.The morphologies,mechanical properties,deformation behaviour,and biological compatibility of RGLS samples were characterised and compared with those in the uniform lattice structure.Both the uniform and RGLS samples achieve a relative density higher than 99%.The graded porosities and pore sizes in the RGLS range from 40%-80% and 330-805 µm,respectively,from the centre to the edge.The chemical etching has significantly removed the harmful partially-melted residual powder particles on the lattice struts.The compressive yield strength of RGLS is 71.5 MPa,much higher than that of the uniform sample (46.5 MPa),despite having a similar relative density of about 46%.The calculated Gibson-Ashby equation and the deformation behaviour simulation by finite element suggest that the dense outer regions with high load-bearing capability could sustain high applied stress,improving the overall strength of RGLS significantly.The cell proliferation study suggests better biological compatibility of the RGLS than the uniform structures.The findings highlight a novel strategy to improve the performance of additively manufactured artificial implants by bio-inspiration.展开更多
Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, how...Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, however, no effective treatments or enough vaccines for COVID-19 are available. The roles of angiotensin converting enzyme 2(ACE2) and spike protein in the treatment of COVID-19 are major areas of research. In this study, we explored the potential of ACE2 and spike protein as targets for the development of antiviral agents against SARS-Co V-2. We analyzed clinical data, genetic data, and receptor binding capability.Clinical data revealed that COVID-19 patients with comorbidities related to an abnormal reninangiotensin system exhibited more early symptoms and poorer prognoses. However, the relationship between ACE2 expression and COVID-19progression is still not clear. Furthermore, if ACE2 is not a good targetable protein, it would not be applicable across a wide range of populations. The spike-S1 receptor-binding domain that interacts with ACE2 showed various amino acid mutations based on sequence analysis. We identified two spike-S1 point mutations(V354 F and V470 A) by receptorligand docking and binding enzyme-linked immunosorbent assays. These variants enhanced the binding of the spike protein to ACE2 receptors and were potentially associated with increased infectivity. Importantly, the number of patients infected with the V354 F and V470 A mutants has increased with the development of the SARS-Co V-2 pandemic. These results suggest that ACE2 and spike-S1 are likely not ideal targets for the design of peptide drugs to treat COVID-19 in different populations.展开更多
A novel asymmetric alkylaminoborazine monomer,2-propylamino-4,6-bis（methylamino）borazine,was synthesized for the first time,and directly polymerized to give a melt-spinnable polyborazine（PBN）.This asymmetric alkyl...A novel asymmetric alkylaminoborazine monomer,2-propylamino-4,6-bis（methylamino）borazine,was synthesized for the first time,and directly polymerized to give a melt-spinnable polyborazine（PBN）.This asymmetric alkylaminoborazine was synthesized by an aminolysis reaction of 2,4,6-trichloroborazine（TCB） with different amines under mild conditions.This route turns out to be much cheaper and simpler than the conventional routes.The chemical composition,structure,molecular weights and ceramic yield were investigated by EA,FTIR,NMR,GPC and TG analysis.The PBN exhibits suitable rheological property for melt-spinning, which suggests that it is a potential precursor for BN fibers.展开更多
BACKGROUND Drain-site hernia(DSH)has an extremely low morbidity and has rarely been reported.Small bowel obstruction is a frequent concurrent condition in most cases of DSH,which commonly occurs at the≥10 mm drain-si...BACKGROUND Drain-site hernia(DSH)has an extremely low morbidity and has rarely been reported.Small bowel obstruction is a frequent concurrent condition in most cases of DSH,which commonly occurs at the≥10 mm drain-site.Here we report a rare case of DSH at the lateral 5 mm port site one month postoperatively without visceral incarceration.Simultaneously,a brief review of the literature was conducted focusing on the risk factors,diagnosis,and prevention strategies for DSH.CASE SUMMARY A 76-year-old male patient was admitted to our institution with intermittent abdominal pain and a local abdominal mass which occurred one month after laparoscopic radical resection of rectal cancer one year ago.A computed tomography scan showed an abdominal wall hernia at the 5 mm former drain-site in the left lower quadrant,and that the content consisted of the large omentum.An elective herniorrhaphy was performed by closing the fascial defect and reinforcing the abdominal wall with a synthetic mesh simultaneously.The postoperative period was uneventful.The patient was discharged seven days after the operation without surgery-related complications at the 1-mo follow-up visit.CONCLUSION Emphasis should be placed on DSH despite the decreased use of intra-abdominal drainage.It is recommended that placement of a surgical drainage tube at the≥10 mm trocar site should be avoided.Moreover,it is advisable to have a comprehensive understanding of the risk factors for DSH and complete closure of the fascial defect at the drainage site for high-risk patients.展开更多
Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requireme...Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requirement for system temperature control because the whole amplification process is isothermal and no efforts are needed to switch between different temperatures.In this paper,we designed and fabricated different kinds of polycarbonate(PC)microfluid chips,explored appropriate reaction condition for LAMP in microenvironment(1 nL→10μL),and developed a microfluidic isothermal amplification detection system.The DNA optimal amplification temperature is obtained;the starting time of exponential amplification of DNA is put forward farther.The optimal condition of DNA amplification in microenvironment,with a little reaction materials and early starting exponential amplification time of DNA are very important for clinic DNA detection and the application of Lab-on-a-Chip.展开更多
基金financially supported by the National Natural Science Foundation of China(52005189)Guangdong Basic and Applied Basic Research Foundation(2019A1515110542 and 2020A1515110699)+1 种基金Guangzhou Foreign Cooperation Projects(2020B1212060049 and 201704030067)Guangdong Academy of Sciences and the University of Birmingham(Contract 17-0551).
文摘Bio-inspired porous metallic scaffolds have tremendous potential to be used as artificial bone substitutes.In this work,a radially graded lattice structure (RGLS),which mimics the structures of natural human bones,was designed and processed by laser powder bed fusion of martensitic Ti-rich TiNi powder.The asymmetric tension-compression behaviour,where the compressive strength is significantly higher than the tensile strength,is observed in this Ti-rich TiNi material,which echoes the mechanical behaviour of bones.The morphologies,mechanical properties,deformation behaviour,and biological compatibility of RGLS samples were characterised and compared with those in the uniform lattice structure.Both the uniform and RGLS samples achieve a relative density higher than 99%.The graded porosities and pore sizes in the RGLS range from 40%-80% and 330-805 µm,respectively,from the centre to the edge.The chemical etching has significantly removed the harmful partially-melted residual powder particles on the lattice struts.The compressive yield strength of RGLS is 71.5 MPa,much higher than that of the uniform sample (46.5 MPa),despite having a similar relative density of about 46%.The calculated Gibson-Ashby equation and the deformation behaviour simulation by finite element suggest that the dense outer regions with high load-bearing capability could sustain high applied stress,improving the overall strength of RGLS significantly.The cell proliferation study suggests better biological compatibility of the RGLS than the uniform structures.The findings highlight a novel strategy to improve the performance of additively manufactured artificial implants by bio-inspiration.
基金supported by the National Key Research and Development Program of China (2018YFD0900602)National Natural Science Foundation of China (31970388, 31701234)+3 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Natural Science Foundation of the Jiangsu Higher Education Institutions (17KJB180006)Natural Science Foundation from Jiangsu Province (BK20160043, BK20151546, 15KJA180004and BK20171035)Jiangsu Distinguished Professor Funding。
文摘Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, however, no effective treatments or enough vaccines for COVID-19 are available. The roles of angiotensin converting enzyme 2(ACE2) and spike protein in the treatment of COVID-19 are major areas of research. In this study, we explored the potential of ACE2 and spike protein as targets for the development of antiviral agents against SARS-Co V-2. We analyzed clinical data, genetic data, and receptor binding capability.Clinical data revealed that COVID-19 patients with comorbidities related to an abnormal reninangiotensin system exhibited more early symptoms and poorer prognoses. However, the relationship between ACE2 expression and COVID-19progression is still not clear. Furthermore, if ACE2 is not a good targetable protein, it would not be applicable across a wide range of populations. The spike-S1 receptor-binding domain that interacts with ACE2 showed various amino acid mutations based on sequence analysis. We identified two spike-S1 point mutations(V354 F and V470 A) by receptorligand docking and binding enzyme-linked immunosorbent assays. These variants enhanced the binding of the spike protein to ACE2 receptors and were potentially associated with increased infectivity. Importantly, the number of patients infected with the V354 F and V470 A mutants has increased with the development of the SARS-Co V-2 pandemic. These results suggest that ACE2 and spike-S1 are likely not ideal targets for the design of peptide drugs to treat COVID-19 in different populations.
基金support from the National 863 Program(No.2006AA03A217)
文摘A novel asymmetric alkylaminoborazine monomer,2-propylamino-4,6-bis（methylamino）borazine,was synthesized for the first time,and directly polymerized to give a melt-spinnable polyborazine（PBN）.This asymmetric alkylaminoborazine was synthesized by an aminolysis reaction of 2,4,6-trichloroborazine（TCB） with different amines under mild conditions.This route turns out to be much cheaper and simpler than the conventional routes.The chemical composition,structure,molecular weights and ceramic yield were investigated by EA,FTIR,NMR,GPC and TG analysis.The PBN exhibits suitable rheological property for melt-spinning, which suggests that it is a potential precursor for BN fibers.
基金Supported by the Project of Health Commission of Hunan Province of ChinaNO. 20201853
文摘BACKGROUND Drain-site hernia(DSH)has an extremely low morbidity and has rarely been reported.Small bowel obstruction is a frequent concurrent condition in most cases of DSH,which commonly occurs at the≥10 mm drain-site.Here we report a rare case of DSH at the lateral 5 mm port site one month postoperatively without visceral incarceration.Simultaneously,a brief review of the literature was conducted focusing on the risk factors,diagnosis,and prevention strategies for DSH.CASE SUMMARY A 76-year-old male patient was admitted to our institution with intermittent abdominal pain and a local abdominal mass which occurred one month after laparoscopic radical resection of rectal cancer one year ago.A computed tomography scan showed an abdominal wall hernia at the 5 mm former drain-site in the left lower quadrant,and that the content consisted of the large omentum.An elective herniorrhaphy was performed by closing the fascial defect and reinforcing the abdominal wall with a synthetic mesh simultaneously.The postoperative period was uneventful.The patient was discharged seven days after the operation without surgery-related complications at the 1-mo follow-up visit.CONCLUSION Emphasis should be placed on DSH despite the decreased use of intra-abdominal drainage.It is recommended that placement of a surgical drainage tube at the≥10 mm trocar site should be avoided.Moreover,it is advisable to have a comprehensive understanding of the risk factors for DSH and complete closure of the fascial defect at the drainage site for high-risk patients.
基金supported by the National Foundation of High Technology of China(2006AA020701 and 2006AA020803)National Program on Key Basic Research Projects 973 of China(2006CB705700)+1 种基金the Nature Science Foundation of Zhejiang Province(2006C21G3210005)Tsinghua-Yuyuan Medicine Foundation(40000510B).
文摘Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requirement for system temperature control because the whole amplification process is isothermal and no efforts are needed to switch between different temperatures.In this paper,we designed and fabricated different kinds of polycarbonate(PC)microfluid chips,explored appropriate reaction condition for LAMP in microenvironment(1 nL→10μL),and developed a microfluidic isothermal amplification detection system.The DNA optimal amplification temperature is obtained;the starting time of exponential amplification of DNA is put forward farther.The optimal condition of DNA amplification in microenvironment,with a little reaction materials and early starting exponential amplification time of DNA are very important for clinic DNA detection and the application of Lab-on-a-Chip.
