Since December 2019,an epidemic caused by novel coronavirus (2019-nCoV) infection has occurred unexpectedly in China.As of 8 pm,31 January 2020,more than 20 pediatric cases have been reported in China.Of these cases,t...Since December 2019,an epidemic caused by novel coronavirus (2019-nCoV) infection has occurred unexpectedly in China.As of 8 pm,31 January 2020,more than 20 pediatric cases have been reported in China.Of these cases,ten patients were identified in Zhejiang Province,with an age of onset ranging from 112 days to 17 years.Following the latest National recommendations for diagnosis and treatment of pneumonia caused by 2019-nCo V (the 4th edition) and current status of clinical practice in Zhejiang Province,recommendations for the diagnosis and treatment of respiratory infection caused by 2019-nCoV for children were drafted by the National Clinical Research Center for Child Health,the National Children's Regional Medical Center,Children's Hospital,Zhejiang University School of Medicine to further standardize the protocol for diagnosis and treatment of respiratory infection in children caused by 2019-nCoV.展开更多
Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parame...Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in nature.Recently,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase responses.Here we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic waves.We experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding elements.By encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three dimensions.The simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured results.We further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic waves.The proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices.展开更多
RNA interference(RNAi)targeting lethal genes in insects has great potential for sustainable crop protection.Compared with traditional double-stranded(ds)RNA delivery systems,nanoparticles such as chitosan,liposomes,an...RNA interference(RNAi)targeting lethal genes in insects has great potential for sustainable crop protection.Compared with traditional double-stranded(ds)RNA delivery systems,nanoparticles such as chitosan,liposomes,and cationic dendrimers offer advantages in delivering dsRNA/small interfering(si)RNA to improve RNAi efficiency,thus promoting the development and practice of RNAi-based pest management strategies.Here,we illustrate the limitations of traditional dsRNA delivery systems,reveal the mechanism of nanoparticle-mediated RNAi,summarize the recent progress and successful applications of nanoparticle-mediated RNAi in pest management,and finally address the prospects of nanoparticle-based RNA pesticides.展开更多
Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms t...Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms to date contain gaps and missing sequences.Here,we report the assembly and analysis of gap-free reference genome sequences for two elite O.sativa xian/indica rice varieties,Zhenshan 97 and Minghui 63,which are being used as a model system for studying heterosis and yield.Gap-free reference genomes provide the opportunity for a global view of the structure and function of centromeres.We show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and structures.In addition,the similarity of CentO repeats in the same chromosome is higher than across chromosomes,supporting a model of local expansion and homogenization.Both genomes have over 395 non-TE genes located in centromere regions,of which∼41%are actively transcribed.Two large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two genomes.The availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.展开更多
Axonal junction defects and an inhibitory environment after spinal cord injury seriously hinder the regeneration of damaged tissues and neuronal functions. At the site of spinal cord injury, regenerative biomaterials ...Axonal junction defects and an inhibitory environment after spinal cord injury seriously hinder the regeneration of damaged tissues and neuronal functions. At the site of spinal cord injury, regenerative biomaterials can fill cavities, deliver curative drugs, and provide adsorption sites for transplanted or host cells. Some regenerative biomaterials can also inhibit apoptosis, inflammation and glial scar formation, or further promote neurogenesis, axonal growth and angiogenesis. This review summarized a variety of biomaterial scaffolds made of natural, synthetic, and combined materials applied to spinal cord injury repair. Although these biomaterial scaffolds have shown a certain therapeutic effect in spinal cord injury repair, there are still many problems to be resolved, such as product standards and material safety and effectiveness.展开更多
目的研究发生胎盘早剥的孕妇在妊娠期止血功能的改变与正常妊娠是否有差异,以及临产前止血功能检测是否有助于产后出血的预测和判断。方法连续入选2013年12月1日至2018年12月1日在北京大学第三医院分娩诊断为胎盘早剥的孕妇,同时根据年...目的研究发生胎盘早剥的孕妇在妊娠期止血功能的改变与正常妊娠是否有差异,以及临产前止血功能检测是否有助于产后出血的预测和判断。方法连续入选2013年12月1日至2018年12月1日在北京大学第三医院分娩诊断为胎盘早剥的孕妇,同时根据年龄和孕周匹配健康妊娠孕妇和妊娠期糖尿病孕妇作为对照。收集入选产妇的临床资料、产后结局及怀孕至分娩期间所有止血功能检查结果等数据并分析。结果连续入选胎盘早剥产妇152例,健康妊娠产妇268例、妊娠期糖尿病产妇101例。正常妊娠过程中,随着妊娠周数增加,PT、APTT和TT都逐渐缩短,Fib、FDP和DD都逐渐升高;妊娠期糖尿病组表现类似变化趋势;而在胎盘早剥组中,Fib(g/L)在妊娠中期后表现下降的趋势,在临产时低于健康妊娠组(4.11±0.17 vs 4.35±0.07,P=0.011)。胎盘早剥孕妇无论是否合并妊娠期糖尿病,临产前Fib(g/L)在产后出血组和非出血组差异均有统计学意义(3.41±1.29 vs 4.30±0.94,P=0.001);ROC分析显示,临产时Fib判断胎盘早剥孕妇发生产后出血的AUC=0.703(95%置信区间为0.596~0.810),取截断值为4.00 g/L,阴性预测值为0.883。结论胎盘早剥孕妇Fib水平不像正常孕妇和妊娠期糖尿病孕妇一样随妊娠周数升高,临产时检测Fib水平应有助于判断胎盘早剥孕妇是否发生产后出血。展开更多
Background： MicroRNAs （miRNAs） function as essential posttranscriptional modulators ofgene expression, and are involved in a wide range of physiologic and pathologic states, including cancer. Numerous miRNAs are de...Background： MicroRNAs （miRNAs） function as essential posttranscriptional modulators ofgene expression, and are involved in a wide range of physiologic and pathologic states, including cancer. Numerous miRNAs are deregulated in hepatocellular carcinoma （HCC）. This study aimed to investigate the role of miR-27a in the development of HCC. Methods： The expression of MiR-27a was measured by quantitative real-time polymerase chain reaction （qRT-PCR）. 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide was used to examine changes in the viability of HepG2, Bel-7402, Bel-7404 hepatoma cell lines associated with up-regulation or down-regulation of miR-27a. A dual-luciferase activity assay was used to verily a target gene ofmiR-27a, lmmunohistochemistry, qRT-PCR, Western blotting analysis, and cell cycle and apoptosis flow cytometric assays were used to elucidate the mechanism by which miR-27a modulates liver cancer cell proliferation. Results： The expression of miR-27a was significantly increased in HCC tissues and HepG2, Bel-7402, Bel-7404 hepatoma cell lines （P 〈 0.05）. We also found that the down-regulation of miR-27a in HepG2 cells dramatically inhibited proliferation, blocked the G1 to S cell cycle transition and induced apoptosis （P 〈 0.05）. In addition, miR-27a directly targeted the 3＇-untranslated region of peroxisonae proliferator-activated receptor y （PPAR-γ）, and ectopic miR-27a expression suppressed PPAR-γ expression on the mRNA and protein levels. The rosiglitazone-induced overexpression of PPAR-γ attenuated the effect of miR-27a in HCC cells. Conclusions： Our findings suggested that miRNA-27a promoted HCC cell proliferation by regulating PPAR-γ expression. MiR-27a may provide a potential therapeutic strategy for HCC treatment.展开更多
Background Oculomotor palsy is a common complication in patients with posterior communicating aneurysm. This study was conducted to investigate the postoperative recovery of patients with posterior communicating aneur...Background Oculomotor palsy is a common complication in patients with posterior communicating aneurysm. This study was conducted to investigate the postoperative recovery of patients with posterior communicating aneurysm complicated with oculomotor palsy and to analyze the factors influencing length of recovery.Methods From 2000 to 2006, 148 patients with posterior communicating aneurysm were treated at our hospital, with 74 of them having concurrent unilateral oculomotor palsy. All of the patients underwent craniotomy after the diagnosis by means of whole-brain digital subtraction angiography （DSA）. The patients were divided into two groups for observation of postoperative recovery during the follow-up period. Patients in group A were treated with simple pedicle clipping of the aneurysm while patients in group B were treated with pedicle clipping of the aneurysm and decompression of the oculomotor nerve.Results Of the 40 patients in group A, 20 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Fourteen patients underwent surgery within 14-30 days, of whom 12 completely recovered within 30-90 days and 2 cases recovered incompletely. The remaining six patients underwent surgery after more than 30 days; of these, four patients recovered completely and two recovered incompletely. Of the 34 cases in group B, 15 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Sixteen patients underwent surgery in 14-30 days, of whom 14 completely recovered in 30-90 days and 2 recovered incompletely. The remaining three patients underwent surgery after more than 30 days, of whom two patients recovered completely and one recovered incompletely.Conclusions Early diagnosis and surgical treatment of patients with unilateral oculomotor palsy induced by posterior communicating aneurysm are important to full postoperative recovery of the oculomotor nerve. No correlation was found, however, between decompression of the oculomotor nerve, such as exci展开更多
文摘Since December 2019,an epidemic caused by novel coronavirus (2019-nCoV) infection has occurred unexpectedly in China.As of 8 pm,31 January 2020,more than 20 pediatric cases have been reported in China.Of these cases,ten patients were identified in Zhejiang Province,with an age of onset ranging from 112 days to 17 years.Following the latest National recommendations for diagnosis and treatment of pneumonia caused by 2019-nCo V (the 4th edition) and current status of clinical practice in Zhejiang Province,recommendations for the diagnosis and treatment of respiratory infection caused by 2019-nCoV for children were drafted by the National Clinical Research Center for Child Health,the National Children's Regional Medical Center,Children's Hospital,Zhejiang University School of Medicine to further standardize the protocol for diagnosis and treatment of respiratory infection in children caused by 2019-nCoV.
基金supported by the National Science Foundation of China(61571117,61522106,61138001,61302018 and 61401089)Natural Science Foundation of the Jiangsu Province(BK2012019)the 111 Project(111-2-05).
文摘Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in nature.Recently,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase responses.Here we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic waves.We experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding elements.By encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three dimensions.The simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured results.We further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic waves.The proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices.
基金the Beijing Natural Science Foundation(6204043)National Natural Science Foundation of China(31900363).
文摘RNA interference(RNAi)targeting lethal genes in insects has great potential for sustainable crop protection.Compared with traditional double-stranded(ds)RNA delivery systems,nanoparticles such as chitosan,liposomes,and cationic dendrimers offer advantages in delivering dsRNA/small interfering(si)RNA to improve RNAi efficiency,thus promoting the development and practice of RNAi-based pest management strategies.Here,we illustrate the limitations of traditional dsRNA delivery systems,reveal the mechanism of nanoparticle-mediated RNAi,summarize the recent progress and successful applications of nanoparticle-mediated RNAi in pest management,and finally address the prospects of nanoparticle-based RNA pesticides.
基金This research was supported by the Natinal Key Research and Development Program of China(2016YFD0100904 and 2016YFD0100802)the National Natural Science Foundation of China(31871269)+1 种基金the Hubei Provincial Natural Science Foundation of China(2019CFA014)Fundamental Research Funds for the Central Universities(2662020SKPY010 to J.Z.).
文摘Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms to date contain gaps and missing sequences.Here,we report the assembly and analysis of gap-free reference genome sequences for two elite O.sativa xian/indica rice varieties,Zhenshan 97 and Minghui 63,which are being used as a model system for studying heterosis and yield.Gap-free reference genomes provide the opportunity for a global view of the structure and function of centromeres.We show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and structures.In addition,the similarity of CentO repeats in the same chromosome is higher than across chromosomes,supporting a model of local expansion and homogenization.Both genomes have over 395 non-TE genes located in centromere regions,of which∼41%are actively transcribed.Two large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two genomes.The availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.
基金supported by the National Natural Science Foundation of China,No.81571213(to BW),No.81800583(to YYX)the 13~(th) Six Talent Peaks Project(C type)of Jiangsu Province of China(to BW)+1 种基金the Medical Science and Technique Development Foundation of Nanjing of China,No.QRX17006(to BW)the Medical Science and Innovation Platform of Nanjing of China,No.ZDX16005(to BW)
文摘Axonal junction defects and an inhibitory environment after spinal cord injury seriously hinder the regeneration of damaged tissues and neuronal functions. At the site of spinal cord injury, regenerative biomaterials can fill cavities, deliver curative drugs, and provide adsorption sites for transplanted or host cells. Some regenerative biomaterials can also inhibit apoptosis, inflammation and glial scar formation, or further promote neurogenesis, axonal growth and angiogenesis. This review summarized a variety of biomaterial scaffolds made of natural, synthetic, and combined materials applied to spinal cord injury repair. Although these biomaterial scaffolds have shown a certain therapeutic effect in spinal cord injury repair, there are still many problems to be resolved, such as product standards and material safety and effectiveness.
文摘目的研究发生胎盘早剥的孕妇在妊娠期止血功能的改变与正常妊娠是否有差异,以及临产前止血功能检测是否有助于产后出血的预测和判断。方法连续入选2013年12月1日至2018年12月1日在北京大学第三医院分娩诊断为胎盘早剥的孕妇,同时根据年龄和孕周匹配健康妊娠孕妇和妊娠期糖尿病孕妇作为对照。收集入选产妇的临床资料、产后结局及怀孕至分娩期间所有止血功能检查结果等数据并分析。结果连续入选胎盘早剥产妇152例,健康妊娠产妇268例、妊娠期糖尿病产妇101例。正常妊娠过程中,随着妊娠周数增加,PT、APTT和TT都逐渐缩短,Fib、FDP和DD都逐渐升高;妊娠期糖尿病组表现类似变化趋势;而在胎盘早剥组中,Fib(g/L)在妊娠中期后表现下降的趋势,在临产时低于健康妊娠组(4.11±0.17 vs 4.35±0.07,P=0.011)。胎盘早剥孕妇无论是否合并妊娠期糖尿病,临产前Fib(g/L)在产后出血组和非出血组差异均有统计学意义(3.41±1.29 vs 4.30±0.94,P=0.001);ROC分析显示,临产时Fib判断胎盘早剥孕妇发生产后出血的AUC=0.703(95%置信区间为0.596~0.810),取截断值为4.00 g/L,阴性预测值为0.883。结论胎盘早剥孕妇Fib水平不像正常孕妇和妊娠期糖尿病孕妇一样随妊娠周数升高,临产时检测Fib水平应有助于判断胎盘早剥孕妇是否发生产后出血。
基金This study was supported by grants from Frontier Interdiscipline Program of Norman Bethune Health Science Center of Jilin University （No. 2013101001）, The Science and Technology Support Program of Jilin Province （No. 3D512K903430）, Young Scholars Program of Norman Bethune Health Science Center of Jilin University （No. 2013201011）, and the Nature Science Foundation of Jilin Province （No. 201215079）.
文摘Background： MicroRNAs （miRNAs） function as essential posttranscriptional modulators ofgene expression, and are involved in a wide range of physiologic and pathologic states, including cancer. Numerous miRNAs are deregulated in hepatocellular carcinoma （HCC）. This study aimed to investigate the role of miR-27a in the development of HCC. Methods： The expression of MiR-27a was measured by quantitative real-time polymerase chain reaction （qRT-PCR）. 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide was used to examine changes in the viability of HepG2, Bel-7402, Bel-7404 hepatoma cell lines associated with up-regulation or down-regulation of miR-27a. A dual-luciferase activity assay was used to verily a target gene ofmiR-27a, lmmunohistochemistry, qRT-PCR, Western blotting analysis, and cell cycle and apoptosis flow cytometric assays were used to elucidate the mechanism by which miR-27a modulates liver cancer cell proliferation. Results： The expression of miR-27a was significantly increased in HCC tissues and HepG2, Bel-7402, Bel-7404 hepatoma cell lines （P 〈 0.05）. We also found that the down-regulation of miR-27a in HepG2 cells dramatically inhibited proliferation, blocked the G1 to S cell cycle transition and induced apoptosis （P 〈 0.05）. In addition, miR-27a directly targeted the 3＇-untranslated region of peroxisonae proliferator-activated receptor y （PPAR-γ）, and ectopic miR-27a expression suppressed PPAR-γ expression on the mRNA and protein levels. The rosiglitazone-induced overexpression of PPAR-γ attenuated the effect of miR-27a in HCC cells. Conclusions： Our findings suggested that miRNA-27a promoted HCC cell proliferation by regulating PPAR-γ expression. MiR-27a may provide a potential therapeutic strategy for HCC treatment.
文摘Background Oculomotor palsy is a common complication in patients with posterior communicating aneurysm. This study was conducted to investigate the postoperative recovery of patients with posterior communicating aneurysm complicated with oculomotor palsy and to analyze the factors influencing length of recovery.Methods From 2000 to 2006, 148 patients with posterior communicating aneurysm were treated at our hospital, with 74 of them having concurrent unilateral oculomotor palsy. All of the patients underwent craniotomy after the diagnosis by means of whole-brain digital subtraction angiography （DSA）. The patients were divided into two groups for observation of postoperative recovery during the follow-up period. Patients in group A were treated with simple pedicle clipping of the aneurysm while patients in group B were treated with pedicle clipping of the aneurysm and decompression of the oculomotor nerve.Results Of the 40 patients in group A, 20 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Fourteen patients underwent surgery within 14-30 days, of whom 12 completely recovered within 30-90 days and 2 cases recovered incompletely. The remaining six patients underwent surgery after more than 30 days; of these, four patients recovered completely and two recovered incompletely. Of the 34 cases in group B, 15 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Sixteen patients underwent surgery in 14-30 days, of whom 14 completely recovered in 30-90 days and 2 recovered incompletely. The remaining three patients underwent surgery after more than 30 days, of whom two patients recovered completely and one recovered incompletely.Conclusions Early diagnosis and surgical treatment of patients with unilateral oculomotor palsy induced by posterior communicating aneurysm are important to full postoperative recovery of the oculomotor nerve. No correlation was found, however, between decompression of the oculomotor nerve, such as exci
