Cooperative autonomous air combat of multiple unmanned aerial vehicles(UAVs)is one of the main combat modes in future air warfare,which becomes even more complicated with highly changeable situation and uncertain info...Cooperative autonomous air combat of multiple unmanned aerial vehicles(UAVs)is one of the main combat modes in future air warfare,which becomes even more complicated with highly changeable situation and uncertain information of the opponents.As such,this paper presents a cooperative decision-making method based on incomplete information dynamic game to generate maneuver strategies for multiple UAVs in air combat.Firstly,a cooperative situation assessment model is presented to measure the overall combat situation.Secondly,an incomplete information dynamic game model is proposed to model the dynamic process of air combat,and a dynamic Bayesian network is designed to infer the tactical intention of the opponent.Then a reinforcement learning framework based on multiagent deep deterministic policy gradient is established to obtain the perfect Bayes-Nash equilibrium solution of the air combat game model.Finally,a series of simulations are conducted to verify the effectiveness of the proposed method,and the simulation results show effective synergies and cooperative tactics.展开更多
Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these...Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these instruments are limited because of their size and complex feedback system.In this study,we demonstrate a miniature fiber optical nanomechanical probe(FONP)that can be used to detect the mechanical properties of single cells and in vivo tissue measurements.A FONP that can operate in air and in liquids was developed by programming a microcantilever probe on the end face of a single-mode fiber using femtosecond laser two-photon polymerization nanolithography.To realize stiffness matching of the FONP and sample,a strategy of customizing the microcantilever’s spring constant according to the sample was proposed based on structure-correlated mechanics.As a proof-of concept,three FONPs with spring constants varying from 0.421 N m^(−1)to 52.6 N m^(−1)by more than two orders of magnitude were prepared.The highest microforce sensitivity was 54.5 nmμN^(−1)and the detection limit was 2.1 nN.The Young’s modulus of heterogeneous soft materials,such as polydimethylsiloxane,muscle tissue of living mice,onion cells,and MCF-7 cells,were successfully measured,which validating the broad applicability of this method.Our strategy provides a universal protocol for directly programming fiber-optic AFMs.Moreover,this method has no special requirements for the size and shape of living biological samples,which is infeasible when using commercial AFMs.FONP has made substantial progress in realizing basic biological discoveries,which may create new biomedical applications that cannot be realized by current AFMs.展开更多
With Newton＇s interpolating formula, we construct a kind of block based Newton-like blending osculatory interpolation.The interpolation provides us many flexible interpolation schemes for choices which include the ex...With Newton＇s interpolating formula, we construct a kind of block based Newton-like blending osculatory interpolation.The interpolation provides us many flexible interpolation schemes for choices which include the expansive Newton＇s polynomial inter- polation as its special case. A bivariate analogy is also discussed and numerical examples are given to show the effectiveness of the interpolation.展开更多
A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical ...A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical example is given.展开更多
[Objectives]To accurately determine the naringin content in Rhizoma Drynariae.[Methods]The high performance liquid chromatography(HPLC)method was applied in the determination of the naringin content in Rhizoma Drynari...[Objectives]To accurately determine the naringin content in Rhizoma Drynariae.[Methods]The high performance liquid chromatography(HPLC)method was applied in the determination of the naringin content in Rhizoma Drynariae.The sample was sonicated at room temperature.The mobile phase was 0.1%phosphoric acid-acetonitrile(75∶25),detected by diode array detector at the wavelength of 284 nm,and quantified by external standard method.[Results]The linearity of naringin was good in the concentration range of 5-500μg/mL with a correlation coefficient of 0.9999.[Conclusions]This method has good linearity,easy operation,correctness and reproducibility as required,and is expected to provide a method for the determination of naringin content in Rhizoma Drynariae.展开更多
[Objectives]The paper was to establish an evaluation method for the uncertainty of stevioside(including stevioside,rebaudioside A,rebaudioside B,rebaudioside C,rebaudioside F,Dulcoside A,rubusoside and steviolbioside)...[Objectives]The paper was to establish an evaluation method for the uncertainty of stevioside(including stevioside,rebaudioside A,rebaudioside B,rebaudioside C,rebaudioside F,Dulcoside A,rubusoside and steviolbioside)content determination in fermented milk based on HPLC.[Methods]The mathematical model of stevioside content and the propagation rate of uncertainty were established,and the sources of uncertainty were analyzed.[Results]The uncertainty mainly came from four main aspects,including standard uncertainty u(C)introduced by solution concentration C,standard uncertainty u(V)introduced by sample volume V,standard uncertainty u(m)introduced by sample mass m weighing and standard uncertainty u(f_(rep))introduced by measurement repeatability of stevioside content after sample dissolution and constant volume.The uncertainty estimation table and fishbone chart of stevioside content X determination were established.The relative synthetic standard uncertainty of stevioside content was obtained,and the standard uncertainty was extended to form the measurement result of stevioside content and its uncertainty report.[Conclusions]The evaluation results can be directly applied to the daily practical detection work.展开更多
Irreversible eye lesions, such as glaucoma and traumatic optic neuropathy, can cause blindness;however, no effective treatments exist. The optic nerve, in particular, lacks the capacity to spontaneously regenerate, re...Irreversible eye lesions, such as glaucoma and traumatic optic neuropathy, can cause blindness;however, no effective treatments exist. The optic nerve, in particular, lacks the capacity to spontaneously regenerate, requiring the development of an effective approach for optic nerve repair, which has proven challenging. Here, we demonstrate that a combination of the small molecules 3BDO and trichostatin A(TSA)—which regulate mTOR and HDAC, respectively—packaged in thermosensitive hydrogel for 4-week-sustained release after intravitreal injection, effectively induced optic nerve regeneration in a mouse model of optic nerve crush injury. Moreover, this combination of 3BDO and TSA also protected axon projections and improved visual responses in an old mouse model(11 months old) of glaucoma. Taken together, our data provide a new, local small molecule-based treatment for the effective induction of optic nerve repair, which may represent a foundation for the development of pharmacological methods to treat irreversible eye diseases.展开更多
As one of the core modules for air traffic flow management,Air Traffic Flow Prediction(ATFP)in the Multi-Airport System(MAS)is a prerequisite for demand and capacity balance in the complex meteorological environment.D...As one of the core modules for air traffic flow management,Air Traffic Flow Prediction(ATFP)in the Multi-Airport System(MAS)is a prerequisite for demand and capacity balance in the complex meteorological environment.Due to the challenge of implicit interaction mechanism among traffic flow,airspace capacity and weather impact,the Weather-aware ATFP(Wa-ATFP)is still a nontrivial issue.In this paper,a novel Multi-faceted Spatio-Temporal Graph Convolutional Network(MSTGCN)is proposed to address the Wa-ATFP within the complex operations of MAS.Firstly,a spatio-temporal graph is constructed with three different nodes,including airport,route,and fix to describe the topology structure of MAS.Secondly,a weather-aware multi-faceted fusion module is proposed to integrate the feature of air traffic flow and the auxiliary features of capacity and weather,which can effectively address the complex impact of severe weather,e.g.,thunderstorms.Thirdly,to capture the latent connections of nodes,an adaptive graph connection constructor is designed.The experimental results with the real-world operational dataset in Guangdong-Hong Kong-Macao Greater Bay Area,China,validate that the proposed approach outperforms the state-of-the-art machine-learning and deep-learning based baseline approaches in performance.展开更多
A functional hybrid nano-hydroxyapatite(carboxymethyl cellulose-phytic acid-n-HA,CMC-PA-n-HA)was prepared by adding CMC and PA.The results of Fourier transformation infrared spectra,X-ray diffraction,thermal gravimetr...A functional hybrid nano-hydroxyapatite(carboxymethyl cellulose-phytic acid-n-HA,CMC-PA-n-HA)was prepared by adding CMC and PA.The results of Fourier transformation infrared spectra,X-ray diffraction,thermal gravimetric analysis and dispersion experiments indicated that the addition of CMC and PA affected the morphology,crystallinity and crystal size of hybrid n-HA,and CMC endowed hybrid n-HA with excellent dispersion.Scanning electron microscope results showed that CMC-PA-n-HA nanoparticle could be uniformly dispersed in chitosan(CS)matrix to obtain composite membrane by casting technology,so that the highest tensile strength of CMC-PA-n-HA/CS composite membrane was 69.64%and 144.45%higher than that of CS membrane and n-HA/CS composite membrane,respectively.Contact angle test showed that CMC-PA-n-HA effectively improved hydrophilicity of the CS membrane.The simulated body fluid immersion results indicated that the CMC-PA-n-HA/CS composite membrane not only exhibited good degradability but also promoted bone-like apatite deposition.The cell proliferation experiments proved that the introduction of PA made the composite membrane have better cell adhesion and proliferation ability.Antibacterial tests demonstrated that PA could effectively improve the antibacterial properties of the composite membrane,which is expected to be applied as guide bone tissue regeneration membrane.展开更多
[Objectives]To make simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.[Methods]A high performance liquid chromatographic method was develo...[Objectives]To make simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.[Methods]A high performance liquid chromatographic method was developed for the simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.After enzymatic digestion,the samples were extracted with hexane for VK_(1),MK-4,MK-7 and MK-9,subjected to gradient elution at excitation wavelength 243 nm and emission wavelength 430 nm,detected by high performance liquid chromatography with fluorescence detector and quantified by external standard method.[Results]The linearity of VK_(1),MK-4,MK-7 and MK-9 was good in the concentration range of 2.5-1000 ng/mL with the correlation coefficients greater than 0.999;The relative standard deviations(RSD)of VK_(1),MK-4,MK-7 and MK-9 in milk powder,liquid milk and yogurt were 1.32%-5.05%,1.10%-2.48% and 2.20%-3.47%,respectively;the recovery rates of VK_(1),MK-4,MK-7 and MK-9 at different levels in milk powder,liquid milk and yogurt were 81.1%-108%,81.8%-103%and 82.1%-99.2%,respectively.[Conclusions]The method is rapid,accurate,reproducible and capable of simultaneous determination of VK_(1),MK-4,MK-7 and MK-9.展开更多
Background： Serum cryptococcal antigen （CrAg） test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this...Background： Serum cryptococcal antigen （CrAg） test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus （HIV） adult patients with pulmonary cryptococcosis and its clinical features. Methods： One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive （CrAg＋ group） and 29 were negative （CrAg- group）. It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio （OR） was used to measure correlation. Student＇s t-test was obtained to analyze continuous variable. Results： No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups （P 〉 0.05 in all）. Nevertheless, diffuse extent lesion was 82.1% in CrAg＋ group and 10.3% in CrAg- group （χ2 = 40.34, P〈 0.001; OR = 39.87）. Conclusions： Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.展开更多
A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode co...A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter（MRP）.To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative（PD） control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.展开更多
The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and ...The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and high-accuracy controllers. In this paper, we propose a linear-quadratic regulator （LQR） design method based on stochastic robustness analysis for the longitudinal dynamics of AHVs. First, input/output feedback linearization is used to design LQRs. Second, subject to various system parameter uncertainties, system robustness is characterized by the probability of stability and desired performance. Then, the mapping rela- tionship between system robustness and LQR parameters is established. Particularly, to maximize system robustness, a novel hybrid particle swarm optimization algorithm is proposed to search for the optimal LQR parameters. During the search iteration, a Chernoff bound algorithm is applied to determine the finite sample size of Monte Carlo evaluation with the given prohabilily levels. Finally, simulation results show that the optimization algorithm can effectively find the optimal solution to the LQR parameters.展开更多
To obtain nano-hydroxyapatite/poly(lactideco-glycolide)(n-HA/PLGA)nanocomposite with superior mechanical properties,here,lignin was chosen to surfacemodify for n-HA through co-precipitation method.The different reacti...To obtain nano-hydroxyapatite/poly(lactideco-glycolide)(n-HA/PLGA)nanocomposite with superior mechanical properties,here,lignin was chosen to surfacemodify for n-HA through co-precipitation method.The different reaction conditions of reaction time,phosphorus source,and the lignin addition amount were studied by fourier transformation infrared spectra,X-ray diffraction,the intuitionistic dispersion experiment,transmission electron microscope and thermal gravimetric analysis.The reaction mechanism and the best appropriate reaction condition were obtained.More importantly,the results of electromechanical universal tester,scanning electron microscope,differential scanning calorimetric analyzer,polarized optical microscopy and dynamic mechanical analysis confirmed that the obtained n-HA could greatly increase the mechanical strength of PLGA,owing to the excellent dispersion and promotion crystallization effect.Moreover,in vitro cell culture experimental results indicated that the n-HA surface-modified by lignin was favorable to improve the cell biocompatibility of PLGA.The study suggested that the introduction of lignin was a novel method to acquire a highly dispersed n-HA,which would provide a new idea to achieve the n-HA/PLGA nanocomposite as bone materials in future,and it would pave the way towards a new application of lignin in biomedical field.展开更多
To the Editor:According to World Health Organization (WHO) histologic classification of lung tumors, primary pulmonary lymphoepithelioma-like carcinoma (LELC), belonging to the other and unclassified carcinoma, is con...To the Editor:According to World Health Organization (WHO) histologic classification of lung tumors, primary pulmonary lymphoepithelioma-like carcinoma (LELC), belonging to the other and unclassified carcinoma, is considered as a rare subtype of variants of lung cancer.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61933010 and 61903301)Shaanxi Aerospace Flight Vehicle Design Key Laboratory。
文摘Cooperative autonomous air combat of multiple unmanned aerial vehicles(UAVs)is one of the main combat modes in future air warfare,which becomes even more complicated with highly changeable situation and uncertain information of the opponents.As such,this paper presents a cooperative decision-making method based on incomplete information dynamic game to generate maneuver strategies for multiple UAVs in air combat.Firstly,a cooperative situation assessment model is presented to measure the overall combat situation.Secondly,an incomplete information dynamic game model is proposed to model the dynamic process of air combat,and a dynamic Bayesian network is designed to infer the tactical intention of the opponent.Then a reinforcement learning framework based on multiagent deep deterministic policy gradient is established to obtain the perfect Bayes-Nash equilibrium solution of the air combat game model.Finally,a series of simulations are conducted to verify the effectiveness of the proposed method,and the simulation results show effective synergies and cooperative tactics.
基金supported by the National Natural Science Foundation of China(NSFC)(62122057,62075136,62175165)Natural Science Foundation of Guangdong Province(2022B1515120061,2019B1515120042)Science and Technology Innovation Commission of Shenzhen(RCYX20200714114524139,JCYJ20200109114001806).
文摘Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these instruments are limited because of their size and complex feedback system.In this study,we demonstrate a miniature fiber optical nanomechanical probe(FONP)that can be used to detect the mechanical properties of single cells and in vivo tissue measurements.A FONP that can operate in air and in liquids was developed by programming a microcantilever probe on the end face of a single-mode fiber using femtosecond laser two-photon polymerization nanolithography.To realize stiffness matching of the FONP and sample,a strategy of customizing the microcantilever’s spring constant according to the sample was proposed based on structure-correlated mechanics.As a proof-of concept,three FONPs with spring constants varying from 0.421 N m^(−1)to 52.6 N m^(−1)by more than two orders of magnitude were prepared.The highest microforce sensitivity was 54.5 nmμN^(−1)and the detection limit was 2.1 nN.The Young’s modulus of heterogeneous soft materials,such as polydimethylsiloxane,muscle tissue of living mice,onion cells,and MCF-7 cells,were successfully measured,which validating the broad applicability of this method.Our strategy provides a universal protocol for directly programming fiber-optic AFMs.Moreover,this method has no special requirements for the size and shape of living biological samples,which is infeasible when using commercial AFMs.FONP has made substantial progress in realizing basic biological discoveries,which may create new biomedical applications that cannot be realized by current AFMs.
基金Supported by the Key Project Foundation of the Department of Education of Anhui Province(No.KJ2008A027)the Project Foundation of the Department of Education of Anhui Province(No.KJ2010B182)
文摘With Newton＇s interpolating formula, we construct a kind of block based Newton-like blending osculatory interpolation.The interpolation provides us many flexible interpolation schemes for choices which include the expansive Newton＇s polynomial inter- polation as its special case. A bivariate analogy is also discussed and numerical examples are given to show the effectiveness of the interpolation.
基金Supported by the National Natural Science Foundation of China under Grant No. 10171026.
文摘A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical example is given.
文摘[Objectives]To accurately determine the naringin content in Rhizoma Drynariae.[Methods]The high performance liquid chromatography(HPLC)method was applied in the determination of the naringin content in Rhizoma Drynariae.The sample was sonicated at room temperature.The mobile phase was 0.1%phosphoric acid-acetonitrile(75∶25),detected by diode array detector at the wavelength of 284 nm,and quantified by external standard method.[Results]The linearity of naringin was good in the concentration range of 5-500μg/mL with a correlation coefficient of 0.9999.[Conclusions]This method has good linearity,easy operation,correctness and reproducibility as required,and is expected to provide a method for the determination of naringin content in Rhizoma Drynariae.
文摘[Objectives]The paper was to establish an evaluation method for the uncertainty of stevioside(including stevioside,rebaudioside A,rebaudioside B,rebaudioside C,rebaudioside F,Dulcoside A,rubusoside and steviolbioside)content determination in fermented milk based on HPLC.[Methods]The mathematical model of stevioside content and the propagation rate of uncertainty were established,and the sources of uncertainty were analyzed.[Results]The uncertainty mainly came from four main aspects,including standard uncertainty u(C)introduced by solution concentration C,standard uncertainty u(V)introduced by sample volume V,standard uncertainty u(m)introduced by sample mass m weighing and standard uncertainty u(f_(rep))introduced by measurement repeatability of stevioside content after sample dissolution and constant volume.The uncertainty estimation table and fishbone chart of stevioside content X determination were established.The relative synthetic standard uncertainty of stevioside content was obtained,and the standard uncertainty was extended to form the measurement result of stevioside content and its uncertainty report.[Conclusions]The evaluation results can be directly applied to the daily practical detection work.
基金supported by the National Natural Science Foundation of China(32288102)。
文摘Irreversible eye lesions, such as glaucoma and traumatic optic neuropathy, can cause blindness;however, no effective treatments exist. The optic nerve, in particular, lacks the capacity to spontaneously regenerate, requiring the development of an effective approach for optic nerve repair, which has proven challenging. Here, we demonstrate that a combination of the small molecules 3BDO and trichostatin A(TSA)—which regulate mTOR and HDAC, respectively—packaged in thermosensitive hydrogel for 4-week-sustained release after intravitreal injection, effectively induced optic nerve regeneration in a mouse model of optic nerve crush injury. Moreover, this combination of 3BDO and TSA also protected axon projections and improved visual responses in an old mouse model(11 months old) of glaucoma. Taken together, our data provide a new, local small molecule-based treatment for the effective induction of optic nerve repair, which may represent a foundation for the development of pharmacological methods to treat irreversible eye diseases.
基金supported by the National Key Research and Development Program of China(No.2022YFB2602402)the National Natural Science Foundation of China(Nos.U2033215 and U2133210).
文摘As one of the core modules for air traffic flow management,Air Traffic Flow Prediction(ATFP)in the Multi-Airport System(MAS)is a prerequisite for demand and capacity balance in the complex meteorological environment.Due to the challenge of implicit interaction mechanism among traffic flow,airspace capacity and weather impact,the Weather-aware ATFP(Wa-ATFP)is still a nontrivial issue.In this paper,a novel Multi-faceted Spatio-Temporal Graph Convolutional Network(MSTGCN)is proposed to address the Wa-ATFP within the complex operations of MAS.Firstly,a spatio-temporal graph is constructed with three different nodes,including airport,route,and fix to describe the topology structure of MAS.Secondly,a weather-aware multi-faceted fusion module is proposed to integrate the feature of air traffic flow and the auxiliary features of capacity and weather,which can effectively address the complex impact of severe weather,e.g.,thunderstorms.Thirdly,to capture the latent connections of nodes,an adaptive graph connection constructor is designed.The experimental results with the real-world operational dataset in Guangdong-Hong Kong-Macao Greater Bay Area,China,validate that the proposed approach outperforms the state-of-the-art machine-learning and deep-learning based baseline approaches in performance.
基金supported by Postgraduate Scientific Research Innovation Project of Hunan Province (China) (Grant No.CX20230518).
文摘A functional hybrid nano-hydroxyapatite(carboxymethyl cellulose-phytic acid-n-HA,CMC-PA-n-HA)was prepared by adding CMC and PA.The results of Fourier transformation infrared spectra,X-ray diffraction,thermal gravimetric analysis and dispersion experiments indicated that the addition of CMC and PA affected the morphology,crystallinity and crystal size of hybrid n-HA,and CMC endowed hybrid n-HA with excellent dispersion.Scanning electron microscope results showed that CMC-PA-n-HA nanoparticle could be uniformly dispersed in chitosan(CS)matrix to obtain composite membrane by casting technology,so that the highest tensile strength of CMC-PA-n-HA/CS composite membrane was 69.64%and 144.45%higher than that of CS membrane and n-HA/CS composite membrane,respectively.Contact angle test showed that CMC-PA-n-HA effectively improved hydrophilicity of the CS membrane.The simulated body fluid immersion results indicated that the CMC-PA-n-HA/CS composite membrane not only exhibited good degradability but also promoted bone-like apatite deposition.The cell proliferation experiments proved that the introduction of PA made the composite membrane have better cell adhesion and proliferation ability.Antibacterial tests demonstrated that PA could effectively improve the antibacterial properties of the composite membrane,which is expected to be applied as guide bone tissue regeneration membrane.
文摘[Objectives]To make simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.[Methods]A high performance liquid chromatographic method was developed for the simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.After enzymatic digestion,the samples were extracted with hexane for VK_(1),MK-4,MK-7 and MK-9,subjected to gradient elution at excitation wavelength 243 nm and emission wavelength 430 nm,detected by high performance liquid chromatography with fluorescence detector and quantified by external standard method.[Results]The linearity of VK_(1),MK-4,MK-7 and MK-9 was good in the concentration range of 2.5-1000 ng/mL with the correlation coefficients greater than 0.999;The relative standard deviations(RSD)of VK_(1),MK-4,MK-7 and MK-9 in milk powder,liquid milk and yogurt were 1.32%-5.05%,1.10%-2.48% and 2.20%-3.47%,respectively;the recovery rates of VK_(1),MK-4,MK-7 and MK-9 at different levels in milk powder,liquid milk and yogurt were 81.1%-108%,81.8%-103%and 82.1%-99.2%,respectively.[Conclusions]The method is rapid,accurate,reproducible and capable of simultaneous determination of VK_(1),MK-4,MK-7 and MK-9.
基金This work was supported by the grants from Guangzhou Programs for Natural Science Foundation of Guangdong Province （No. 201707010282）, Scientific Research Project of Guangzhou （No. 2017A030310286）, the National Natural Science Foundation of China （No. 81670071 ）, and Science and Technology Planning Project of Guangdong Province （No. 2014A020212627）.
文摘Background： Serum cryptococcal antigen （CrAg） test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus （HIV） adult patients with pulmonary cryptococcosis and its clinical features. Methods： One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive （CrAg＋ group） and 29 were negative （CrAg- group）. It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio （OR） was used to measure correlation. Student＇s t-test was obtained to analyze continuous variable. Results： No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups （P 〉 0.05 in all）. Nevertheless, diffuse extent lesion was 82.1% in CrAg＋ group and 10.3% in CrAg- group （χ2 = 40.34, P〈 0.001; OR = 39.87）. Conclusions： Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.
基金supported by the National Natural Science Foundation of China(Nos.51675430,11402044,and U1537213)
文摘A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter（MRP）.To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative（PD） control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.
基金the National Natural Science Foundation of China （No. 11672235）
文摘The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and high-accuracy controllers. In this paper, we propose a linear-quadratic regulator （LQR） design method based on stochastic robustness analysis for the longitudinal dynamics of AHVs. First, input/output feedback linearization is used to design LQRs. Second, subject to various system parameter uncertainties, system robustness is characterized by the probability of stability and desired performance. Then, the mapping rela- tionship between system robustness and LQR parameters is established. Particularly, to maximize system robustness, a novel hybrid particle swarm optimization algorithm is proposed to search for the optimal LQR parameters. During the search iteration, a Chernoff bound algorithm is applied to determine the finite sample size of Monte Carlo evaluation with the given prohabilily levels. Finally, simulation results show that the optimization algorithm can effectively find the optimal solution to the LQR parameters.
基金the support of the Science and Technology Project of Changsha(Grant No.kq1907132)Natural Science Foundation of Province(Grant No.2020JJ4430)+5 种基金Opening Found of Key Laboratory of Chemical Biology&Traditional Chinese Medicine Research(Ministry of Education of China)Hunan Normal University(Grant No.KLCBTCMR201812)Hunan Engineering Laboratory for Preparation Technology of Poly(vinyl alcohol)Fiber MaterialHuaihua University(Grant No.HGY201812)the National Natural Science Foundation of China(Grant No.51803055)Hunan Provincial Key Research and Development Program(Grant No.2018GK2062).
文摘To obtain nano-hydroxyapatite/poly(lactideco-glycolide)(n-HA/PLGA)nanocomposite with superior mechanical properties,here,lignin was chosen to surfacemodify for n-HA through co-precipitation method.The different reaction conditions of reaction time,phosphorus source,and the lignin addition amount were studied by fourier transformation infrared spectra,X-ray diffraction,the intuitionistic dispersion experiment,transmission electron microscope and thermal gravimetric analysis.The reaction mechanism and the best appropriate reaction condition were obtained.More importantly,the results of electromechanical universal tester,scanning electron microscope,differential scanning calorimetric analyzer,polarized optical microscopy and dynamic mechanical analysis confirmed that the obtained n-HA could greatly increase the mechanical strength of PLGA,owing to the excellent dispersion and promotion crystallization effect.Moreover,in vitro cell culture experimental results indicated that the n-HA surface-modified by lignin was favorable to improve the cell biocompatibility of PLGA.The study suggested that the introduction of lignin was a novel method to acquire a highly dispersed n-HA,which would provide a new idea to achieve the n-HA/PLGA nanocomposite as bone materials in future,and it would pave the way towards a new application of lignin in biomedical field.
基金grants from the Guangzhou Programs for Natural Science Foundation of Guangdong Province (No.201707010282)Scientific Research Project of Guangdong (No.2017A030310286)Science and Technology Planning Project of Guangdong Province (No.2014A020212627 and No. 2016A020215099).
文摘To the Editor:According to World Health Organization (WHO) histologic classification of lung tumors, primary pulmonary lymphoepithelioma-like carcinoma (LELC), belonging to the other and unclassified carcinoma, is considered as a rare subtype of variants of lung cancer.
