The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate ne...The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.展开更多
Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactiv...Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.展开更多
A class of distributions called Box-Cox symmetric was proposed for random variables with asymmetric distributions. This class allows through its structure an interpretation of the parameters in terms of quantiles (in ...A class of distributions called Box-Cox symmetric was proposed for random variables with asymmetric distributions. This class allows through its structure an interpretation of the parameters in terms of quantiles (in particular, the median), relative dispersion and skewness. This study presents the initial </span><span style="font-family:Verdana;">results of the computational development of basic functions of each of the</span><span style="font-family:Verdana;"> distributions that make up the Box-Cox symmetric class. Four functions have been developed to compose a routine in software R up to now. These functions are related to random numbers generation, probability density function, cumulative distribution function, and quantile function associated to a given probability. Examples of implemented functions were presented. The gamlss routine was used to check the performance of developed functions.展开更多
Basic helix-loop-helix (bHLH) transcription factors regulate the differentiation of various tissues in a vast diversity of species. The bHLH protein Atonal was first identified as a proneural gene involved in the fo...Basic helix-loop-helix (bHLH) transcription factors regulate the differentiation of various tissues in a vast diversity of species. The bHLH protein Atonal was first identified as a proneural gene involved in the formation of mechanosensory cells and photoreceptor cells in Drosophila (larman et al., 1993, 1994). Atonal is expressed in sensory organ precursors and is required and sufficient for the development of chordotonal organs (Jar- man et al., 1993). Moreover, Atonal expression is observed in the developing eye and is essential for the differentiation of R8 photoreceptors, which are the first photoreceptors that appear during development. Atonal is not involved in the formation of other photoreceptors (R1-R7) directly. However, R8 photore- ceptors recruit other photoreceptors from the surrounding cells (Jarman et al., 1994).展开更多
Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of ...Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin (a neural precursor cell marker)-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.展开更多
The thermal decomposition process of basic magnesium carbonate was investigated. Firstly, Basic magnesium carbonate was prepared from magnesite, and the characteristics of the product were detected by X-ray diffracti...The thermal decomposition process of basic magnesium carbonate was investigated. Firstly, Basic magnesium carbonate was prepared from magnesite, and the characteristics of the product were detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Subsequently, the thermal decomposition process of basic magnesium carbonate in air was studied by thermogravimetry-differential thermogravimetry (TG-DTG). The results of XRD confirm that the chemical composition of basic magnesium carbonate is 4MgCO3·Mg(OH)2·4H2O. And the SEM images show that the sample is in sheet structure, with a diameter of 0.1-1 μm. The TG-DTG results demonstrate that there are two steps in the thermal decomposition process of basic magnesium carbonate. The apparent activation energies (E) were calculated by Flyrm-Wall-Ozawa method. It is obtained from Coats-Redfem's equation and Malek method that the mechanism functions of the two decomposition stages are D3 and A1.5, respectively. And then, the kinetic equations of the two steps were deduced as well.展开更多
An amine capillary column was developed in a fused-silica capillary as stationary phase and applied to separation of basic compounds by capillary electrochromatography (CEC). The functionalized capillary was prepared ...An amine capillary column was developed in a fused-silica capillary as stationary phase and applied to separation of basic compounds by capillary electrochromatography (CEC). The functionalized capillary was prepared by inmobilization of 3-Aminopropyl)triethoxysilane (APTES). The CEC conditions including APTES and buffer concentration, pH and applied voltage were investigated to obtain the optimal CEC system for the separation of three anesthetics as basic test molecules. The capillary column provided an efficiency of up to 20,000 plates/m. Lidocaine, ketamine and xilacine were baseline separated under the running conditions with 10 mM Na2HPO4 pH 9.0 as BGE. The applied voltage was 5 kV temperature was set at 25oC and UV detection was performed. The resolutions were 4.97 and 1.53 for ketamine, lidocaine and xilacine, respectively. The column used in CEC mode showed better separation of the anesthetics compared with those used in the capillary zone mode. The comparison with reversed stationary phases used in HPLC in terms of resolution (Rs), sensitivity (LOD), efficiency (N), precision (RSD), asymmetry (T) was also performed. This study provided an alternative way for the CEC separation of basic compounds and demonstrated the improvement in the chromatographic parameters.展开更多
Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication (HNBM), with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNB...Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication (HNBM), with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNBM rising to the national strategy was analyzed through the aspects of technology features, historical characteristics, irreplaceability, function and value hierarchy, and the key problems. As the major achievement of the practice of scientific research and historical selec- tion, HNBM played an irreplaceable role in the climatic conditions, scientific breed- ing, and seed production in disaster relief, protecting the safety of the seed industry and Iocational advantages. Based on the analysis on the functions, values and ex- isted problems of HNBM, the function and value hierarchical structure of HNBM was established through introducing concepts of value engineering, industrial clusters and regional economy. But to fully achieve the industrial clustering development and functional values of HNBM, it needed to solve the key problems existed in top-level planning, experimental bases, system design, hardware construction and ecological security. Some suggestions were put forward in this paper, including setting up key scientific research protection zones, improving the regulations and policies safeguard mechanism and management system of HNBM, drawing up and carrying out the base development planning of HNBM, and striving for financial support from national policies.展开更多
The effect of sinter basicity on softening-melting behaviors of mixed burden made from chromium-bearing vanadium-titanium magnetite(Cr-V-Ti magnetite) was investigated and the function mechanism was simultaneously ana...The effect of sinter basicity on softening-melting behaviors of mixed burden made from chromium-bearing vanadium-titanium magnetite(Cr-V-Ti magnetite) was investigated and the function mechanism was simultaneously analyzed.The results show that with increasing sinter basicity from 1.71 to 2.36,the softening interval tends to increase from 149.3 ℃ to 181.7 ℃while the melting interval tends to decrease from 178.0 ℃ to 136.7 ℃.The location of cohesive zone moves downwards firstly and then ascends slightly,but the cohesive zone becomes thinner.The softening-melting characteristic value becomes small,which indicates that the permeability of burden column is improved.The dripping ratio of mixed burden tends to increase firstly and then decrease,which comes to the highest value of 74.50%when the sinter basicity is 2.13.The content and the recovery of V and Cr in dripping iron are all increased.The generation amount of components with high melting point in slag becomes little with the increase of sinter basicity,which could improve the permeability of mixed burden.Taking softening-melting behaviors of mixed burden and recovery of valuable elements into account,the proper sinter basicity is no less than 2.13 for smelting mixed burden made from Cr-V-Ti magnetite in blast furnace.展开更多
The aim of this work is to analyse the global dynamics of an extended mathematical model of Hepatitis C virus (HCV) infection in vivo with cellular proliferation, spontaneous cure and hepatocyte homeostasis. We firstl...The aim of this work is to analyse the global dynamics of an extended mathematical model of Hepatitis C virus (HCV) infection in vivo with cellular proliferation, spontaneous cure and hepatocyte homeostasis. We firstly prove the existence of local and global solutions of the model and establish some properties of this solution as positivity and asymptotic behaviour. Secondly we show, by the construction of appropriate Lyapunov functions, that the uninfected equilibrium and the unique infected equilibrium of the mathematical model of HCV are globally asymptotically stable respectively when the threshold number and when .展开更多
Burundi, a country in East Africa with a temperate climate, has experienced in recent years a worrying growth of the Malaria epidemic. In this paper, a deterministic model of the transmission dynamics of malaria paras...Burundi, a country in East Africa with a temperate climate, has experienced in recent years a worrying growth of the Malaria epidemic. In this paper, a deterministic model of the transmission dynamics of malaria parasite in mosquito and human populations was formulated. The mathematical model was developed based on the SEIR model. An epidemiological threshold, <em>R</em><sub>0</sub>, called the basic reproduction number was calculated. The disease-free equilibrium point was locally asymptotically stable if <em>R</em><sub>0</sub> < 1 and unstable if <em>R</em><sub>0</sub> > 1. Using a Lyapunov function, we proved that this disease-free equilibrium point was globally asymptotically stable whenever the basic reproduction number is less than unity. The existence and uniqueness of endemic equilibrium were examined. With the Lyapunov function, we proved also that the endemic equilibrium is globally asymptotically stable if <em>R</em><sub>0</sub> > 1. Finally, the system of equations was solved numerically according to Burundi’s data on malaria. The result from our model shows that, in order to reduce the spread of Malaria in Burundi, the number of mosquito bites on human per unit of time (<em>σ</em>), the vector population of mosquitoes (<em>N<sub>v</sub></em>), the probability of being infected for a human bitten by an infectious mosquito per unit of time (<em>b</em>) and the probability of being infected for a mosquito per unit of time (<em>c</em>) must be reduced by applying optimal control measures.展开更多
We propose and analyze an epidemiological model to evaluate the effectiveness of bed nets as a prophylactic measure in malaria-endemic areas. The main purpose in this work is the modeling of the aggressiveness of anop...We propose and analyze an epidemiological model to evaluate the effectiveness of bed nets as a prophylactic measure in malaria-endemic areas. The main purpose in this work is the modeling of the aggressiveness of anopheles mosquitoes relative to the way humans use to protect themselves against bites of mosquitoes. This model is a system of several differential equations: the number of equations depends on the particular assumptions of the model. We compute the basic reproduction number, and show that if, the disease free equilibrium (DFE) is globally asymptotically stable on the non-negative orthant. If, the system admits a unique endemic equilibrium (EE) that is globally and asymptotically stable. Numerical simulations are presented corresponding to scenarios typical of malaria-endemic areas, based on data collected in the literature. Finally, we discuss the relative effectiveness of different kinds of bed nets.展开更多
In the last three decades Synchrotron radiation became an indispensable experimental tool for chemical and structural analysis of nano-scaled properties in solid state physics, chemistry, materials science and life sc...In the last three decades Synchrotron radiation became an indispensable experimental tool for chemical and structural analysis of nano-scaled properties in solid state physics, chemistry, materials science and life science thereby rendering the explanation of the macroscopic behavior of the materials and systems under investigation. Especially the techniques known as Anomalous Small-Angle X-ray Scattering provide deep insight into the materials structural architecture according to the different chemical components on lengths scales starting just above the atomic scale (≈1 nm) up to several 100 nm. The techniques sensitivity to the different chemical components makes use of the energy dependence of the atomic scattering factors, which are different for all chemical elements, thereby disentangling the nanostructure of the different chemical components by the signature of the elemental X-ray absorption edges i.e. by employing synchrotron radiation. The paper wants to focus on the application of an algorithm from linear algebra in the field of synchrotron radiation. It provides a closer look to the algebraic prerequisites, which govern the system of linear equations established by these experimental techniques and its solution by solving the eigenvector problem. The pair correlation functions of the so-called basic scattering functions are expressed as a linear combination of eigenvectors.展开更多
This article analyzes The Kite Runner with the help of spactial narrative. The novel will be analyzed from three angles—the function of spatial narrative, the basic unit of spatial narrative, the periphery of spatial...This article analyzes The Kite Runner with the help of spactial narrative. The novel will be analyzed from three angles—the function of spatial narrative, the basic unit of spatial narrative, the periphery of spatial narrative and the overall effect presented in the novel by using these narrative techniques.展开更多
n this paper, the possibility of wavelet transform applied to compute the vertical deformation is discussed. Both two dimension plane equation of wavelet transform and B-wavelet based on basic spline function are dedu...n this paper, the possibility of wavelet transform applied to compute the vertical deformation is discussed. Both two dimension plane equation of wavelet transform and B-wavelet based on basic spline function are deduced. According to the equation and B-wavelet, multi-periods vertical deformation data which were measured from 1971 to 1995 in Hexi-Qilian Mountain region, Gansu Province are calculated. The results are: ① The multi-resolution analysis of wavelet transform can filter the different spatial wavelength in vertical deformation information on different scales effectively and let us to see the heterogeneous in distribution of vertical deformation clearly, therefore, it is an important tool in investigating the relationship between the vertical deformation and the seismicity; ② The main variation of both the first and second results in wavelet transform mainly takes place along the main faults which explains that the short wave variation of vertical deformation is caused by the faults activities; ③ The wavelet transform of vertical deformation in Hexi-Qilian Mountain area shows that the vertical deformation in southeast parts of Hexi region was larger than that in other parts and there were several moderate earthquakes such as Menyuan Ms=6.4 earthquake in 1986, Jingtai Ms=6.2 earthquake in 1990, Yongdeng Ms=5.8 earthquake in 1995. The vertical deformation in the northwest part of the region was not so large as that in southeast part where ware no strong earthquakes.展开更多
The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processin...The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.展开更多
There are several examples of spaces of univariate functions for which we have a characterization of all sets of knots which are poised for the interpolation problem. For the standard spaces of univariate polynomials,...There are several examples of spaces of univariate functions for which we have a characterization of all sets of knots which are poised for the interpolation problem. For the standard spaces of univariate polynomials, or spline functions the mentioned results are well-known. In contrast with this, there are no such results in the bivariate case. As an exception, one may consider only the Pascal classic theorem, in the interpolation theory interpretation. In this paper, we consider a space of bivariate piecewise linear functions, for which we can readily find out whether the given node set is poised or not. The main tool we use for this purpose is the reduction by a basic subproblem, introduced in this paper.展开更多
Objective To compare the different effects of endothelia progenitor cells ( EPCs ) or basic fibroblast growth factor (b-FGF) intromyocardial infusion on cardiac function and neovascularization for dilated cardiomy...Objective To compare the different effects of endothelia progenitor cells ( EPCs ) or basic fibroblast growth factor (b-FGF) intromyocardial infusion on cardiac function and neovascularization for dilated cardiomyopathy( DCM) rats. Methods Fifty adult female rats received inguinal subcutaneous injections of isoproterenol (ISO, 250 mg/kg) for induction of DCM. Four weeks later, the model rats were randomly divided into EPCs group, b-FGF group and control group. The 2×106 EPCs ( resolved in 100 μL PBS) , 100 μL b-FGF ( lO0 μg/mL ) and 100 μL PBS were evenly transplanted into the myocardium of EPCs group, b-FGF group and control group, respectively. Three months later, echocardiographic examination and regional myocardial blood flow (RMBF) measurement were performed. EPCs were traced by fluorescence in situ hybridization (FISH). The protein and mRNA expression of b-FGF in each group was measured by ELISA assay and reverse transcription-polymerase chain reaction ( RT-PCR ) . Results Three months after transplantation, sry positive cells were detected only in EPCs group. The cardiac function as well as RMBF was significantly improved in EPCs group compared with b-FGF group or control group. There was higher capillary density in EPCs group. The protein and mRNA expression of b-FGF was stronger than b-FGF group and control group. Conclusion Transplantation of EPCs can improve cardiac function, induce neovascularization and increase RMBF for DCM rats. The treatment with EPCs has better effect than administration of b-FGF alone.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82272171(to ZY),82271403(to XL),81941011(to XL),31971279(to ZY),31730030(to XL)the Natural Science Foundation of Beijing,No.7222004(to HD).
文摘The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.
基金supported by the National Natural Science Foundation of China,Nos.81941011(to XL),31771053(to HD),31730030(to XL),31971279(to ZY),31900749(to PH),31650001(to XL),31320103903(to XL),31670988(to ZY)the Natural Science Foundation of Beijing,Nos.7222004(to HD)+1 种基金a grant from Ministry of Science and Technology of China,Nos.2017YFC1104002(to ZY),2017YFC1104001(to XL)a grant from Beihang University,No.JKF-YG-22-B001(to FH)。
文摘Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.
文摘A class of distributions called Box-Cox symmetric was proposed for random variables with asymmetric distributions. This class allows through its structure an interpretation of the parameters in terms of quantiles (in particular, the median), relative dispersion and skewness. This study presents the initial </span><span style="font-family:Verdana;">results of the computational development of basic functions of each of the</span><span style="font-family:Verdana;"> distributions that make up the Box-Cox symmetric class. Four functions have been developed to compose a routine in software R up to now. These functions are related to random numbers generation, probability density function, cumulative distribution function, and quantile function associated to a given probability. Examples of implemented functions were presented. The gamlss routine was used to check the performance of developed functions.
基金supported by grants from the Ministry of Education,Culture,Sports,Science and Technology in Japan and Naito Foundation to TCthe Japan Society for the Promotion of Science to MO and TC
文摘Basic helix-loop-helix (bHLH) transcription factors regulate the differentiation of various tissues in a vast diversity of species. The bHLH protein Atonal was first identified as a proneural gene involved in the formation of mechanosensory cells and photoreceptor cells in Drosophila (larman et al., 1993, 1994). Atonal is expressed in sensory organ precursors and is required and sufficient for the development of chordotonal organs (Jar- man et al., 1993). Moreover, Atonal expression is observed in the developing eye and is essential for the differentiation of R8 photoreceptors, which are the first photoreceptors that appear during development. Atonal is not involved in the formation of other photoreceptors (R1-R7) directly. However, R8 photore- ceptors recruit other photoreceptors from the surrounding cells (Jarman et al., 1994).
基金the National Natural Science Foundation of China,grants No.30772304,30973166,and 81171863
文摘Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin (a neural precursor cell marker)-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.
基金Project(20876160) supported by the National Natural Science Foundation of China
文摘The thermal decomposition process of basic magnesium carbonate was investigated. Firstly, Basic magnesium carbonate was prepared from magnesite, and the characteristics of the product were detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Subsequently, the thermal decomposition process of basic magnesium carbonate in air was studied by thermogravimetry-differential thermogravimetry (TG-DTG). The results of XRD confirm that the chemical composition of basic magnesium carbonate is 4MgCO3·Mg(OH)2·4H2O. And the SEM images show that the sample is in sheet structure, with a diameter of 0.1-1 μm. The TG-DTG results demonstrate that there are two steps in the thermal decomposition process of basic magnesium carbonate. The apparent activation energies (E) were calculated by Flyrm-Wall-Ozawa method. It is obtained from Coats-Redfem's equation and Malek method that the mechanism functions of the two decomposition stages are D3 and A1.5, respectively. And then, the kinetic equations of the two steps were deduced as well.
文摘An amine capillary column was developed in a fused-silica capillary as stationary phase and applied to separation of basic compounds by capillary electrochromatography (CEC). The functionalized capillary was prepared by inmobilization of 3-Aminopropyl)triethoxysilane (APTES). The CEC conditions including APTES and buffer concentration, pH and applied voltage were investigated to obtain the optimal CEC system for the separation of three anesthetics as basic test molecules. The capillary column provided an efficiency of up to 20,000 plates/m. Lidocaine, ketamine and xilacine were baseline separated under the running conditions with 10 mM Na2HPO4 pH 9.0 as BGE. The applied voltage was 5 kV temperature was set at 25oC and UV detection was performed. The resolutions were 4.97 and 1.53 for ketamine, lidocaine and xilacine, respectively. The column used in CEC mode showed better separation of the anesthetics compared with those used in the capillary zone mode. The comparison with reversed stationary phases used in HPLC in terms of resolution (Rs), sensitivity (LOD), efficiency (N), precision (RSD), asymmetry (T) was also performed. This study provided an alternative way for the CEC separation of basic compounds and demonstrated the improvement in the chromatographic parameters.
基金Supported by the Natural Science Foundation of Hainan Province(313114)the Sanya Science Project(2013YD89)the Social Science Project(SYSK14-08)~~
文摘Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication (HNBM), with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNBM rising to the national strategy was analyzed through the aspects of technology features, historical characteristics, irreplaceability, function and value hierarchy, and the key problems. As the major achievement of the practice of scientific research and historical selec- tion, HNBM played an irreplaceable role in the climatic conditions, scientific breed- ing, and seed production in disaster relief, protecting the safety of the seed industry and Iocational advantages. Based on the analysis on the functions, values and ex- isted problems of HNBM, the function and value hierarchical structure of HNBM was established through introducing concepts of value engineering, industrial clusters and regional economy. But to fully achieve the industrial clustering development and functional values of HNBM, it needed to solve the key problems existed in top-level planning, experimental bases, system design, hardware construction and ecological security. Some suggestions were put forward in this paper, including setting up key scientific research protection zones, improving the regulations and policies safeguard mechanism and management system of HNBM, drawing up and carrying out the base development planning of HNBM, and striving for financial support from national policies.
基金Project(51574067)supported by the National Natural Science Fundation of ChinaProjects(2012AA062302,2012AA062304)supported by the National High Technology Research and Development Program of ChinaProject(N110202001)supported by the Fundamental Research Funds for the Central Universities of China
文摘The effect of sinter basicity on softening-melting behaviors of mixed burden made from chromium-bearing vanadium-titanium magnetite(Cr-V-Ti magnetite) was investigated and the function mechanism was simultaneously analyzed.The results show that with increasing sinter basicity from 1.71 to 2.36,the softening interval tends to increase from 149.3 ℃ to 181.7 ℃while the melting interval tends to decrease from 178.0 ℃ to 136.7 ℃.The location of cohesive zone moves downwards firstly and then ascends slightly,but the cohesive zone becomes thinner.The softening-melting characteristic value becomes small,which indicates that the permeability of burden column is improved.The dripping ratio of mixed burden tends to increase firstly and then decrease,which comes to the highest value of 74.50%when the sinter basicity is 2.13.The content and the recovery of V and Cr in dripping iron are all increased.The generation amount of components with high melting point in slag becomes little with the increase of sinter basicity,which could improve the permeability of mixed burden.Taking softening-melting behaviors of mixed burden and recovery of valuable elements into account,the proper sinter basicity is no less than 2.13 for smelting mixed burden made from Cr-V-Ti magnetite in blast furnace.
文摘The aim of this work is to analyse the global dynamics of an extended mathematical model of Hepatitis C virus (HCV) infection in vivo with cellular proliferation, spontaneous cure and hepatocyte homeostasis. We firstly prove the existence of local and global solutions of the model and establish some properties of this solution as positivity and asymptotic behaviour. Secondly we show, by the construction of appropriate Lyapunov functions, that the uninfected equilibrium and the unique infected equilibrium of the mathematical model of HCV are globally asymptotically stable respectively when the threshold number and when .
文摘Burundi, a country in East Africa with a temperate climate, has experienced in recent years a worrying growth of the Malaria epidemic. In this paper, a deterministic model of the transmission dynamics of malaria parasite in mosquito and human populations was formulated. The mathematical model was developed based on the SEIR model. An epidemiological threshold, <em>R</em><sub>0</sub>, called the basic reproduction number was calculated. The disease-free equilibrium point was locally asymptotically stable if <em>R</em><sub>0</sub> < 1 and unstable if <em>R</em><sub>0</sub> > 1. Using a Lyapunov function, we proved that this disease-free equilibrium point was globally asymptotically stable whenever the basic reproduction number is less than unity. The existence and uniqueness of endemic equilibrium were examined. With the Lyapunov function, we proved also that the endemic equilibrium is globally asymptotically stable if <em>R</em><sub>0</sub> > 1. Finally, the system of equations was solved numerically according to Burundi’s data on malaria. The result from our model shows that, in order to reduce the spread of Malaria in Burundi, the number of mosquito bites on human per unit of time (<em>σ</em>), the vector population of mosquitoes (<em>N<sub>v</sub></em>), the probability of being infected for a human bitten by an infectious mosquito per unit of time (<em>b</em>) and the probability of being infected for a mosquito per unit of time (<em>c</em>) must be reduced by applying optimal control measures.
文摘We propose and analyze an epidemiological model to evaluate the effectiveness of bed nets as a prophylactic measure in malaria-endemic areas. The main purpose in this work is the modeling of the aggressiveness of anopheles mosquitoes relative to the way humans use to protect themselves against bites of mosquitoes. This model is a system of several differential equations: the number of equations depends on the particular assumptions of the model. We compute the basic reproduction number, and show that if, the disease free equilibrium (DFE) is globally asymptotically stable on the non-negative orthant. If, the system admits a unique endemic equilibrium (EE) that is globally and asymptotically stable. Numerical simulations are presented corresponding to scenarios typical of malaria-endemic areas, based on data collected in the literature. Finally, we discuss the relative effectiveness of different kinds of bed nets.
文摘In the last three decades Synchrotron radiation became an indispensable experimental tool for chemical and structural analysis of nano-scaled properties in solid state physics, chemistry, materials science and life science thereby rendering the explanation of the macroscopic behavior of the materials and systems under investigation. Especially the techniques known as Anomalous Small-Angle X-ray Scattering provide deep insight into the materials structural architecture according to the different chemical components on lengths scales starting just above the atomic scale (≈1 nm) up to several 100 nm. The techniques sensitivity to the different chemical components makes use of the energy dependence of the atomic scattering factors, which are different for all chemical elements, thereby disentangling the nanostructure of the different chemical components by the signature of the elemental X-ray absorption edges i.e. by employing synchrotron radiation. The paper wants to focus on the application of an algorithm from linear algebra in the field of synchrotron radiation. It provides a closer look to the algebraic prerequisites, which govern the system of linear equations established by these experimental techniques and its solution by solving the eigenvector problem. The pair correlation functions of the so-called basic scattering functions are expressed as a linear combination of eigenvectors.
文摘This article analyzes The Kite Runner with the help of spactial narrative. The novel will be analyzed from three angles—the function of spatial narrative, the basic unit of spatial narrative, the periphery of spatial narrative and the overall effect presented in the novel by using these narrative techniques.
文摘n this paper, the possibility of wavelet transform applied to compute the vertical deformation is discussed. Both two dimension plane equation of wavelet transform and B-wavelet based on basic spline function are deduced. According to the equation and B-wavelet, multi-periods vertical deformation data which were measured from 1971 to 1995 in Hexi-Qilian Mountain region, Gansu Province are calculated. The results are: ① The multi-resolution analysis of wavelet transform can filter the different spatial wavelength in vertical deformation information on different scales effectively and let us to see the heterogeneous in distribution of vertical deformation clearly, therefore, it is an important tool in investigating the relationship between the vertical deformation and the seismicity; ② The main variation of both the first and second results in wavelet transform mainly takes place along the main faults which explains that the short wave variation of vertical deformation is caused by the faults activities; ③ The wavelet transform of vertical deformation in Hexi-Qilian Mountain area shows that the vertical deformation in southeast parts of Hexi region was larger than that in other parts and there were several moderate earthquakes such as Menyuan Ms=6.4 earthquake in 1986, Jingtai Ms=6.2 earthquake in 1990, Yongdeng Ms=5.8 earthquake in 1995. The vertical deformation in the northwest part of the region was not so large as that in southeast part where ware no strong earthquakes.
基金supported by the National Natural Science Foundation of China,No,90707005,61001046 and 61204018the Natural Science Foundation of Education Department of Jiangsu Province,No.11KJB510023the Special Foundation and Open Foundation of State Key Laboratory of Bioelectronics of Southeast University,No.2011E05
文摘The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.
文摘There are several examples of spaces of univariate functions for which we have a characterization of all sets of knots which are poised for the interpolation problem. For the standard spaces of univariate polynomials, or spline functions the mentioned results are well-known. In contrast with this, there are no such results in the bivariate case. As an exception, one may consider only the Pascal classic theorem, in the interpolation theory interpretation. In this paper, we consider a space of bivariate piecewise linear functions, for which we can readily find out whether the given node set is poised or not. The main tool we use for this purpose is the reduction by a basic subproblem, introduced in this paper.
文摘Objective To compare the different effects of endothelia progenitor cells ( EPCs ) or basic fibroblast growth factor (b-FGF) intromyocardial infusion on cardiac function and neovascularization for dilated cardiomyopathy( DCM) rats. Methods Fifty adult female rats received inguinal subcutaneous injections of isoproterenol (ISO, 250 mg/kg) for induction of DCM. Four weeks later, the model rats were randomly divided into EPCs group, b-FGF group and control group. The 2×106 EPCs ( resolved in 100 μL PBS) , 100 μL b-FGF ( lO0 μg/mL ) and 100 μL PBS were evenly transplanted into the myocardium of EPCs group, b-FGF group and control group, respectively. Three months later, echocardiographic examination and regional myocardial blood flow (RMBF) measurement were performed. EPCs were traced by fluorescence in situ hybridization (FISH). The protein and mRNA expression of b-FGF in each group was measured by ELISA assay and reverse transcription-polymerase chain reaction ( RT-PCR ) . Results Three months after transplantation, sry positive cells were detected only in EPCs group. The cardiac function as well as RMBF was significantly improved in EPCs group compared with b-FGF group or control group. There was higher capillary density in EPCs group. The protein and mRNA expression of b-FGF was stronger than b-FGF group and control group. Conclusion Transplantation of EPCs can improve cardiac function, induce neovascularization and increase RMBF for DCM rats. The treatment with EPCs has better effect than administration of b-FGF alone.