Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative r...Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now,which is time-consuming and requires expensive instrumentation,and the confirmation of variants relies on further sequencing techniques.Herein,we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid,highly sensitivity and specificity for the detection of SARS-CoV-2 variant.To enhance the sensing capability,gold electrodes are uniformly decorated with electro-deposited gold nanoparticles.Using DNA template identical to SARS-CoV-2 Delta spike gene sequence as model,our biosensor exhibits excellent analytical detection limit(50 fM)and high linearity(R2=0.987)over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification assays.The detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas system.Furthermore,based on the wireless micro-electrochemical platform,the proposed biosensor reveals promising application ability in point-of-care testing.展开更多
The imaging plane of inverse synthetic aperture radar （ISAR） is the projection plane of the target. When taking an image using the range-Doppler theory, the imaging plane may have a spatial-variant property, which c...The imaging plane of inverse synthetic aperture radar （ISAR） is the projection plane of the target. When taking an image using the range-Doppler theory, the imaging plane may have a spatial-variant property, which causes the change of scatter＇s projection position and results in migration through resolution cells, In this study, we focus on the spatial-variant property of the imaging plane of a three-axis-stabilized space target. The innovative contributions are as follows. 1） The target motion model in orbit is provided based on a two-body model. 2） The instantaneous imaging plane is determined by the method of vector analysis. 3） Three Euler angles are introduced to describe the spatial-variant property of the imaging plane, and the image quality is analyzed. The simulation results confirm the analysis of the spatial-variant property. The research in this study is significant for the selection of the imaging segment, and provides the evidence for the following data processing and compensation algorithm.展开更多
Based on the concept of discrete adiabatic invariant, this paper studies the perturbation to Mei symmetry and Mei adiabatic invariants of the discrete generalized Birkhoffian system. The discrete Mei exact invariant i...Based on the concept of discrete adiabatic invariant, this paper studies the perturbation to Mei symmetry and Mei adiabatic invariants of the discrete generalized Birkhoffian system. The discrete Mei exact invariant induced from the Mei symmetry of the system without perturbation is given. The criterion of the perturbation to Mei symmetry is established and the discrete Mei adiabatic invariant induced from the perturbation to Mei symmetry is obtained. Meanwhile, an example is discussed to illustrate the application of the results.展开更多
The paper gives a detail analysis on the necessity of rapid hydraulic support design, and presents a computer-aided rapid variant design system for hydraulic support. The system integrates the type selection and embod...The paper gives a detail analysis on the necessity of rapid hydraulic support design, and presents a computer-aided rapid variant design system for hydraulic support. The system integrates the type selection and embodiment design of hydraulic support. Case-based reasoning and rule-based reasoning are the main reasoning methods. Several crucial problems are discussed.展开更多
This article studies bounded traveling wave solutions of variant Boussinesq equation with a dissipation term and dissipation effect on them. Firstly, we make qualitative analysis to the bounded traveling wave solution...This article studies bounded traveling wave solutions of variant Boussinesq equation with a dissipation term and dissipation effect on them. Firstly, we make qualitative analysis to the bounded traveling wave solutions for the above equation by the theory and method of planar dynamical systems, and obtain their existent conditions, number, and general shape. Secondly, we investigate the dissipation effect on the shape evolution of bounded traveling wave solutions. We find out a critical value r^＊ which can characterize the scale of dissipation effect, and prove that the bounded traveling wave solutions appear as kink profile waves if ｜r｜≥ r^＊; while they appear as damped oscillatory waves if ｜r｜ 〈 r^＊. We also obtain kink profile solitary wave solutions with and without dissipation effect. On the basis of the above discussion, we sensibly design the structure of the approximate damped oscillatory solutions according to the orbits evolution relation corresponding to the component u（ξ） in the global phase portraits, and then obtain the approximate solutions （u（ξ）, H（ξ））. Furthermore, by using homogenization principle, we give their error estimates by establishing the integral equation which reflects the relation between exact and approximate solutions. Finally, we discuss the dissipation effect on the amplitude, frequency, and energy decay of the bounded traveling wave solutions.展开更多
Over past decades,takotsubo cardiomyopathy(TTC)has drawn a substantial interest as a unique form of acute and reversible cardiomyopathy that usually emerges in response to adrenergic hyperactivation associated with a ...Over past decades,takotsubo cardiomyopathy(TTC)has drawn a substantial interest as a unique form of acute and reversible cardiomyopathy that usually emerges in response to adrenergic hyperactivation associated with a variety of emotional and physical triggers.[1,2]Even though,this phenomenon is generally characterized by an apical balloning pattern(classical variant),it might occasionally present with atypical morphological variants including mid-ventricular,inverted and focal forms of myocardial involvement.展开更多
Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. R...Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. Recent studies demonstrated that a naturally occurring variant V127 of human PrPC is intrinsically resistant to prion conversion and aggregation, and can completely prevent prion diseases. However, the underlying molecular mechanism remains elusive. Herein we perform multiple microsecond molecular dynamics simulations on both wildtype (WT) and V127 variant of human PrPC to understand at atomic level the protective effect of V127 variant. Our simulations show that G127V mutation not only increases the rigidity of the S2–H2 loop between strand-2 (S2) and helix-2 (H2), but also allosterically enhances the stability of the H2 C-terminal region. Interestingly, previous studies reported that animals with rigid S2–H2 loop usually do not develop prion diseases, and the increase in H2 C-terminal stability can prevent misfolding and oligomerization of prion protein. The allosteric paths from G/V127 to H2 C-terminal region are identified using dynamical network analyses. Moreover, community network analyses illustrate that G127V mutation enhances the global correlations and intra-molecular interactions of PrP, thus stabilizing the overall PrPC structure and inhibiting its conversion into PrPSc. This study provides mechanistic understanding of human V127 variant in preventing prion conversion which may be helpful for the rational design of potent anti-prion compounds.展开更多
A class of third-order convergence methods of solving roots for non-linear equation,which are variant Newton＇s method, are given. Their convergence properties are proved. They are at least third order convergence nea...A class of third-order convergence methods of solving roots for non-linear equation,which are variant Newton＇s method, are given. Their convergence properties are proved. They are at least third order convergence near simple root and one order convergence near multiple roots. In the end, numerical tests are given and compared with other known Newton＇s methods. The results show that the proposed methods have some more advantages than others. They enrich the methods to find the roots of non-linear equations and they are important in both theory and application.展开更多
In this paper the generalized Bianchi's identities for the variant constrained system (GBIVOS)w ith non-invariant action integral and constraint conditions was derived, and the strong and weak conservation laws fo...In this paper the generalized Bianchi's identities for the variant constrained system (GBIVOS)w ith non-invariant action integral and constraint conditions was derived, and the strong and weak conservation laws for such system was deduced. The preliminary applications of the GBIVCS to the case for some models of field theories was given. The Dirac constraint of such system was discussed.展开更多
Australian English is one of the variants of English. The words usage, pronunciation, grammar and vocabulary of Aus?tralian English differ from British English and American English because of its unique geographical e...Australian English is one of the variants of English. The words usage, pronunciation, grammar and vocabulary of Aus?tralian English differ from British English and American English because of its unique geographical environment, historical condi?tions, and aboriginal culture. A brief introduction to Australian English is given at the beginning. And then the authors will define the variants of Australian English from three perspectives respectively: historical influence, geographical characteristics and aborigi?nal factors. Aimed to improve understanding of Australian English and encourage more researchers to conduct further studies on international English.展开更多
基金support from the Innovation Team Project of Department of Education of Guangdong Province(No.2018KCXTD026)Guangdong Scientific and Technological Project(2019B1515120043,2020A151501612,2021A1515220109,2022B1515020093)+1 种基金Science and Technology Innovation Commission of Shenzhen(Grant No.KCXFZ20201221173413038)Longhua District Science and Innovation Commission Project Grants of Shenzhen(JCYJ201904).
文摘Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now,which is time-consuming and requires expensive instrumentation,and the confirmation of variants relies on further sequencing techniques.Herein,we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid,highly sensitivity and specificity for the detection of SARS-CoV-2 variant.To enhance the sensing capability,gold electrodes are uniformly decorated with electro-deposited gold nanoparticles.Using DNA template identical to SARS-CoV-2 Delta spike gene sequence as model,our biosensor exhibits excellent analytical detection limit(50 fM)and high linearity(R2=0.987)over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification assays.The detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas system.Furthermore,based on the wireless micro-electrochemical platform,the proposed biosensor reveals promising application ability in point-of-care testing.
基金Project supported by the National Natural Science Foundation of China(Grant No.61401024)the Shanghai Aerospace Science and Technology Innovation Foundation,China(Grant No.SAST201240)the Basic Research Foundation of Beijing Institute of Technology(Grant No.20140542001)
文摘The imaging plane of inverse synthetic aperture radar （ISAR） is the projection plane of the target. When taking an image using the range-Doppler theory, the imaging plane may have a spatial-variant property, which causes the change of scatter＇s projection position and results in migration through resolution cells, In this study, we focus on the spatial-variant property of the imaging plane of a three-axis-stabilized space target. The innovative contributions are as follows. 1） The target motion model in orbit is provided based on a two-body model. 2） The instantaneous imaging plane is determined by the method of vector analysis. 3） Three Euler angles are introduced to describe the spatial-variant property of the imaging plane, and the image quality is analyzed. The simulation results confirm the analysis of the spatial-variant property. The research in this study is significant for the selection of the imaging segment, and provides the evidence for the following data processing and compensation algorithm.
基金Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. 09CX04018A)
文摘Based on the concept of discrete adiabatic invariant, this paper studies the perturbation to Mei symmetry and Mei adiabatic invariants of the discrete generalized Birkhoffian system. The discrete Mei exact invariant induced from the Mei symmetry of the system without perturbation is given. The criterion of the perturbation to Mei symmetry is established and the discrete Mei adiabatic invariant induced from the perturbation to Mei symmetry is obtained. Meanwhile, an example is discussed to illustrate the application of the results.
文摘The paper gives a detail analysis on the necessity of rapid hydraulic support design, and presents a computer-aided rapid variant design system for hydraulic support. The system integrates the type selection and embodiment design of hydraulic support. Case-based reasoning and rule-based reasoning are the main reasoning methods. Several crucial problems are discussed.
基金supported by National Natural ScienceFoundation of China(11071164)Innovation Program of Shanghai Municipal Education Commission(13ZZ118)Shanghai Leading Academic Discipline Project(XTKX2012)
文摘This article studies bounded traveling wave solutions of variant Boussinesq equation with a dissipation term and dissipation effect on them. Firstly, we make qualitative analysis to the bounded traveling wave solutions for the above equation by the theory and method of planar dynamical systems, and obtain their existent conditions, number, and general shape. Secondly, we investigate the dissipation effect on the shape evolution of bounded traveling wave solutions. We find out a critical value r^＊ which can characterize the scale of dissipation effect, and prove that the bounded traveling wave solutions appear as kink profile waves if ｜r｜≥ r^＊; while they appear as damped oscillatory waves if ｜r｜ 〈 r^＊. We also obtain kink profile solitary wave solutions with and without dissipation effect. On the basis of the above discussion, we sensibly design the structure of the approximate damped oscillatory solutions according to the orbits evolution relation corresponding to the component u（ξ） in the global phase portraits, and then obtain the approximate solutions （u（ξ）, H（ξ））. Furthermore, by using homogenization principle, we give their error estimates by establishing the integral equation which reflects the relation between exact and approximate solutions. Finally, we discuss the dissipation effect on the amplitude, frequency, and energy decay of the bounded traveling wave solutions.
文摘Over past decades,takotsubo cardiomyopathy(TTC)has drawn a substantial interest as a unique form of acute and reversible cardiomyopathy that usually emerges in response to adrenergic hyperactivation associated with a variety of emotional and physical triggers.[1,2]Even though,this phenomenon is generally characterized by an apical balloning pattern(classical variant),it might occasionally present with atypical morphological variants including mid-ventricular,inverted and focal forms of myocardial involvement.
基金Project supported by the Key Program of the National Key Research and Development Program of China (Grant No. 2016YFA0501702)the National Natural Science Foundation of China (Grant No. 11674065)。
文摘Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. Recent studies demonstrated that a naturally occurring variant V127 of human PrPC is intrinsically resistant to prion conversion and aggregation, and can completely prevent prion diseases. However, the underlying molecular mechanism remains elusive. Herein we perform multiple microsecond molecular dynamics simulations on both wildtype (WT) and V127 variant of human PrPC to understand at atomic level the protective effect of V127 variant. Our simulations show that G127V mutation not only increases the rigidity of the S2–H2 loop between strand-2 (S2) and helix-2 (H2), but also allosterically enhances the stability of the H2 C-terminal region. Interestingly, previous studies reported that animals with rigid S2–H2 loop usually do not develop prion diseases, and the increase in H2 C-terminal stability can prevent misfolding and oligomerization of prion protein. The allosteric paths from G/V127 to H2 C-terminal region are identified using dynamical network analyses. Moreover, community network analyses illustrate that G127V mutation enhances the global correlations and intra-molecular interactions of PrP, thus stabilizing the overall PrPC structure and inhibiting its conversion into PrPSc. This study provides mechanistic understanding of human V127 variant in preventing prion conversion which may be helpful for the rational design of potent anti-prion compounds.
基金Foundation item： Supported by the National Science Foundation of China（10701066）
文摘A class of third-order convergence methods of solving roots for non-linear equation,which are variant Newton＇s method, are given. Their convergence properties are proved. They are at least third order convergence near simple root and one order convergence near multiple roots. In the end, numerical tests are given and compared with other known Newton＇s methods. The results show that the proposed methods have some more advantages than others. They enrich the methods to find the roots of non-linear equations and they are important in both theory and application.
基金This work was supported by Beijing Science Foundation of the People's Republie of China.
文摘In this paper the generalized Bianchi's identities for the variant constrained system (GBIVOS)w ith non-invariant action integral and constraint conditions was derived, and the strong and weak conservation laws for such system was deduced. The preliminary applications of the GBIVCS to the case for some models of field theories was given. The Dirac constraint of such system was discussed.
文摘Australian English is one of the variants of English. The words usage, pronunciation, grammar and vocabulary of Aus?tralian English differ from British English and American English because of its unique geographical environment, historical condi?tions, and aboriginal culture. A brief introduction to Australian English is given at the beginning. And then the authors will define the variants of Australian English from three perspectives respectively: historical influence, geographical characteristics and aborigi?nal factors. Aimed to improve understanding of Australian English and encourage more researchers to conduct further studies on international English.
