Dynamic light scattering(DLS)is a nondestructive,well-established technique for the size characterization of proteins,nanoparticles,polymers,and colloidal dispersions.However,current DLS techniques are only applied to...Dynamic light scattering(DLS)is a nondestructive,well-established technique for the size characterization of proteins,nanoparticles,polymers,and colloidal dispersions.However,current DLS techniques are only applied to particle groups of single composition due to the limitation of their inversion algorithm.In this study,we propose a particle size distribution inversion algorithm based on the Tikhnonov regularization method that can be applied to the dual-substance particle mixture.The algorithm retrieves the particle size distributions of two substances,respectively,by taking advantage of their refractive index differences.The simulation results reveal that the algorithm has excellent accuracy and stability when the scattering angle is 30°.Instead of the original identity matrix,the first-order difference matrix and second-order difference matrix are used as the regular matrix when utilizing the Tikhnonov algorithm,which obviously improves the anti-interference,accuracy,and stability of the algorithm.Furthermore,the inversion of particle size distribution is carried out at a 0.01%–1%noise level,which shows that the algorithm has an available antinoise ability.Finally,experimental particle size measurements for a mixture of polystyrene beads and toner particles demonstrate that the proposed algorithm is superior to the traditional Tikhnonov algorithm in applicability and accuracy.展开更多
With the intensification of population aging and the implementation of the three-child policy,the elderly care pressure of Chinese families continues to rise.Therefore,accelerating the construction of a new intelligen...With the intensification of population aging and the implementation of the three-child policy,the elderly care pressure of Chinese families continues to rise.Therefore,accelerating the construction of a new intelligent elderly care service model is an important measure to actively respond to population aging,ease the burden of family elderly care and promote high-quality economic development.In view of this,this study analyzed the intelligent elderly care service to explore the relevant countermeasures of the intelligent elderly care service in the context of fewer children.展开更多
Electrochemical NO reduction reaction(NORR)to NH3 emerges as a fascinating approach to achieve both the migration of NO pollutant and the green synthesis of NH3.In this contribution,within the framework of computation...Electrochemical NO reduction reaction(NORR)to NH3 emerges as a fascinating approach to achieve both the migration of NO pollutant and the green synthesis of NH3.In this contribution,within the framework of computational hydrogen model and constant-potential implicit solvent model,the NORR electrocatalyzed by a novel transition-metal-anchored SnOSe armchair nanotube(TM@SnOSe_ANT)was investigated using density functional theory calculations.Through the checking in terms of stability,activity,and selectivity,Sc-and Y@SnOSe_ANTs were screened out from the twenty-five candidates.Considering the effects of pH,solvent environment,as well as applied potential,only Sc@SnOSe_ANT is found to be most promising.The predicted surface area normalized capacitance is 11.4μF/cm^(2),and the highest NORR performance can be achieved at the U_(RHE) of-0.58 V in the acid environment.The high activity originates from the mediate adsorption strength of OH.These findings add a new perspective that the nanotube can be served as a highly promising electrocatalyst towards NORR.展开更多
Cardiac fibrosis is a pathological response characterized by excessive deposition of fibrous connective tissue within the heart.It typically occurs following cardiac injuries or diseases.However,the lack of suitable m...Cardiac fibrosis is a pathological response characterized by excessive deposition of fibrous connective tissue within the heart.It typically occurs following cardiac injuries or diseases.However,the lack of suitable models for disease modeling and high-throughput drug discovery has hindered the establishment of an effective treatments for cardiac fibrosis.The emergence and rapid progress of stem-cell and lineage reprogramming technology offer an unprecedented opportunity to develop an improved humanized and patient-specific model for studying cardiac fibrosis,providing a platform for screening potential drugs and synchronously elucidating the underlying molecular mechanisms.Furthermore,reprogramming cardiac fibroblasts into cardiomyocyte-like cells to reduce scar volume and induce myocardial tissue regeneration is a promising approach in treating cardiac fibrosis.In this review,we summarize the current advancements in stem cell technologies applied to study cardiac fibrosis and provide insights for future investigations into its mechanisms,drug discovery as well as therapy method.展开更多
To the Editor:Parkinson disease(PD)is the second most common neurodegenerative disorder associated with significant disability and negative impact on quality of life(QoL),affecting 2%to 3%of the population≥65 years o...To the Editor:Parkinson disease(PD)is the second most common neurodegenerative disorder associated with significant disability and negative impact on quality of life(QoL),affecting 2%to 3%of the population≥65 years of age.^([1])Although the disorder is defined by motor features including asymmetric tremor,bradykinesia,and rigidity,various non-motor features are typically seen,including cognitive impairment,depression,sensory symptoms,autonomic dysfunction,and sleep disturbances.Due to the complexity,PD is challenging to treat.There are currently no effective treatments to prevent or halt the progression of PD.展开更多
A stably transfected CHO cell line coexpressing G551D-CFTR and iodide-sensitive yellow fluorescent protein mutant EYFP-H148Q-I152L was successfully established and used as assay model to identify small-molecule activa...A stably transfected CHO cell line coexpressing G551D-CFTR and iodide-sensitive yellow fluorescent protein mutant EYFP-H148Q-I152L was successfully established and used as assay model to identify small-molecule activators of G551D-CFTR chloride channel from 100000 diverse combinatorial compounds by high throughput screening on a customized Beckman robotic system. A bicyclooctane compound was identified to activate G551D-CFTR chloride channel with high-affinity(K d=1.8 μmol/L). The activity of the bicyclooctane compound is G551D-CFTR-specific, reversible and non-toxic. The G551D-CFTR activator may be useful as a tool to study the mutant G551D-CFTR chloride channel structure and transport properties and as a candidate drug to cure cystic fibrosis caused by G551D-CFTR mutation.展开更多
In a permanent magnet synchronous generator(PMSG)system,conversion systems are major points of failure that create expensive and time-consuming problems.Fault detection is usually used to achieve a steady system.This ...In a permanent magnet synchronous generator(PMSG)system,conversion systems are major points of failure that create expensive and time-consuming problems.Fault detection is usually used to achieve a steady system.This paper presents a full analysis of a PMSG system for wind turbines(WT)and proposes a fault detection method using correlation features.The proposed method is motivated by the balance among the three-phase currents both before and after an opencircuit fault occurs in a converter of the PMSG system.It is unnecessary to analyze the output waveforms of a converter during fault detection.In this study,two correlation features of stator currents,the mean and covariation,are extracted to train an artificial neural network(ANN),thereby enhancing the performance of the proposed method under different wind speed conditions.Moreover,additional sensors and the collection of a massive amount of data are not required.Model simulations of an ideal inverter and a PMSG system are conducted using PSCAD software.The simulation results show that the proposed method can detect the locations of faulty switches with a diagnostic rate greater than 99.4%for the ideal inverter,and the PMSG drives settings at different wind speeds.展开更多
We propose a positivity preserving entropy decreasing finite volume scheme for nonlinear nonlocal equations with a gradient flow structure.These properties allow for accurate computations of stationary states and long...We propose a positivity preserving entropy decreasing finite volume scheme for nonlinear nonlocal equations with a gradient flow structure.These properties allow for accurate computations of stationary states and long-time asymptotics demonstrated by suitably chosen test cases in which these features of the scheme are essential.The proposed scheme is able to cope with non-smooth stationary states,different time scales including metastability,as well as concentrations and self-similar behavior induced by singular nonlocal kernels.We use the scheme to explore properties of these equations beyond their present theoretical knowledge.展开更多
The drawbacks of the traditional multi-hop structure of wireless sensor networks(WSNS)are susceptible to reflection,scattering and diffraction,serious attenuation of signal intensity and phase deviation due to various...The drawbacks of the traditional multi-hop structure of wireless sensor networks(WSNS)are susceptible to reflection,scattering and diffraction,serious attenuation of signal intensity and phase deviation due to various obstacles in cultivated land environment and mountains.In this paper,the wireless signal intensity is measured and curve fitting is done respectively in both open environment and obstacle-environment with both sending and receiving height of 0 m,1 m,and 2 m.It is found out that packet loss probability is too high when an obstacle exists.In such a case,unmanned aerial vehicle(UAV)is introduced to activate terrestrial nodes and operation mechanism of distributed storage.Experimental results show that both ground-to-air barrier-free communication and communication with obstacles can greatly reduce the energy consumption of each node and packet loss probability,thus greatly improving the reliability of UAV-WSN system.展开更多
Temporal changes of dominant microbial populations in groundwater in response to the leachate from Shanghai Laogang Landfill were investigated. Concentrations of dissolved redox relevant species in groundwater suggest...Temporal changes of dominant microbial populations in groundwater in response to the leachate from Shanghai Laogang Landfill were investigated. Concentrations of dissolved redox relevant species in groundwater suggested that the dominating redox process had changed from denitrification to methane production/sulfate reduction due to landfilling. Dominant microbial populations were determined using restriction fragment length polymorphism(RFLP) analyses of 16S rRNA gene libraries, which were further studied by sequencing and phylogenetic analyses. The results indicated that obvious shifts of dominant microbial populations had occurred in groundwater in response to the pollution of leachate. The closest relatives of some dominant clones are accordant with the dominating redox processes determined by hydrochemical analyses, based on the GenBank's indications on the ability to perform redox reactions.展开更多
Aim To develop a sensitive competitive ELBA for the determination of biotinin transformed yeast culture media. Methods The ELBA plate was firstly coated with Mycoplasmahyopneumoniae, and then successively incubated wi...Aim To develop a sensitive competitive ELBA for the determination of biotinin transformed yeast culture media. Methods The ELBA plate was firstly coated with Mycoplasmahyopneumoniae, and then successively incubated with rabbit anti-Mycoplasma hyopneumoniae serum andgoat anti-rabbit IgG-biotin to form the solid biotin, which competed with the biotin in the solution(standard or sample) for the limited streptavidin-horse radish peroxidase conjugate. The standardcalibration curve for biotin analysis was constructed in the range of 50 - 2000 ng·L^(-1). ResultsThe detection limit for biotin was found to be 83 ng·L^(-1), which was about 1000 times lower thanthe lowest determination concentration in the reported ELISA for biotin analysis. The relativestandard deviations for the spiked samples at biotin concentrations of 200 ng·L^(-1), 500ng·L^(-1), and 1000 ng·L^(-1) were 24.87%, 6.15% , and 7.86% , respectively, with the averagerecovery of 101.13% . The wild yeast and its sixty-three transformed yeast culture media wereapplied to the developed ELBA for the determination of biotin. It was found that the biotinconcentrations in more than 85% of the tested samples were enhanced with different increase factorsafter transformation. Conclusion Utilization of Mycoplasma hyopneumoniae as the coating proteinimproves the precision and accuracy of the ELBA assay, which might be used for the biotin assay inother media.展开更多
Characteristic set method of polynomial equation solving has been widely spread and its implementation in software has been urged to consider in recent years. Several packages for the method are implemented in some co...Characteristic set method of polynomial equation solving has been widely spread and its implementation in software has been urged to consider in recent years. Several packages for the method are implemented in some computer algebra systems, such as REDUCE and Maple. In order to improve the efficiency of the method, we have developed a computer algebra system ″ELIMINO″ written in C language and implemented on Linux operation system on a PC. The authors wish to share with the reader the knowledge and experiences about the design and development of software package of the characteristic set method.展开更多
To evaluate possible use of microwave- enhanced H2O2-based （MW/H2O2） process to degrade trace nitrobenzene （NB） in water, a series of batch experiments were conducted. The results showed that 2450MHz microwave irr...To evaluate possible use of microwave- enhanced H2O2-based （MW/H2O2） process to degrade trace nitrobenzene （NB） in water, a series of batch experiments were conducted. The results showed that 2450MHz microwave irradiation significantly enhanced oxidative decomposition of nitrobenzene （NB） in a H2O2 system. About 90% NB was degraded by the MW/H2O2 process in 30 min. Moreover, the MW/H2O2 process could enhanced the oxidative degradation of NB even at relatively low temperature （50℃）. When the initial concentration of NB was 300gg/L, the optimum ratio of H2O2 to NB and MW power were 70 and 300W respectively. The presence of humic acid significantly increased H2O2 dosage. The ultraviolet absorbance at 254 nm （UV254） indicated degradation of NB was stepwise and some intermediates were produced. The gas chromatography-mass spectrometric （GC-MS） analysis showed that main intermediates were nitrophenolic and carbonyl compounds.展开更多
A thiazolidinone CFTR inhibitor(CFTR_ inh-172 ) was synthesized by a three-step procedure with trifluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally by means of...A thiazolidinone CFTR inhibitor(CFTR_ inh-172 ) was synthesized by a three-step procedure with trifluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally by means of 1H NMR and functionally in a CFTR-expressing cell line FRT/hCFTR/EYFP-H148Q by both fluorescent and electrophysiological methods. A large amount(100 g) of high-quality small molecule thiazolidinone CFTR chloride channel inhibitor,CFTR_ inh-172 ,can be produced with this simple three-step synthetic procedure. The structure of the final product 2-thioxo-3-(3-trifluromethylphenyl)-5-[4-carboxyphenyl- methylene]-4-thiazolidinone was confirmed by 1H NMR. The overall yield was 58% with a purity over 99% as analyzed by HPLC. The synthesized CFTR_ inh-172 specifically inhibited CFTR chloride channel function in a cell-based fluorescence assay( K _d≈1.5 μmol/L) and in a Ussing chamber-based short-circuit current assay( K _d≈0.2 μmol/L),indicating better quality than that of the commercial combinatorial compound. The synthesized inhibitor is nontoxic to cultured cells at a high concentration and to mouse at a high dose. The synthetic procedure developed here can be used to produce a large amount of the high-quality CFTR_ inh-172 suitable for antidiarrheal studies and for creation of cystic fibrosis models in large animals. The procedure can be used to synthesize radiolabled CFTR_ inh-172 for in vivo pharmacokinetics studies.展开更多
Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan City.GeoDa software was used to eliminate the insignificant factors by st...Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan City.GeoDa software was used to eliminate the insignificant factors by stepwise regression analysis;NORM software was adopted to construct the multiple imputation models;EM algorithm and the augmentation algorithm were applied to fit multiple linear regression equations to construct five different filling datasets.Statistical analysis is performed on the imputation data set in order to calculate the mean and variance of each data set,and the weight is determined according to the differences.Finally,comprehensive integration is implemented to achieve the imputation expression of missing values.The results showed that in the three missing cases where the PRICE variable was missing and the deletion rate was 5%,the PRICE variable was missing and the deletion rate was 10%,and the PRICE variable and the CBD variable were both missing.The new method compared to the traditional multiple filling methods of true value closer ratio is 75%to 25%,62.5%to 37.5%,100%to 0%.Therefore,the new method is obviously better than the traditional multiple imputation methods,and the missing value data estimated by the new method bears certain reference value.展开更多
he interaction of lanthanide (Ln￣(3+))ions with trchosanthin(TCS)was investi-gated using Tb￣(3+) as fluorescent probe. The metal-binding sites of the protein were probed by means of adding the Tb￣(3+) into the prot...he interaction of lanthanide (Ln￣(3+))ions with trchosanthin(TCS)was investi-gated using Tb￣(3+) as fluorescent probe. The metal-binding sites of the protein were probed by means of adding the Tb￣(3+) into the protein solutions. If other Ln￣(3+) ions exist in the Tb￣(3+) protein complex system, they would compete against Tb￣(3+) in the binding sites of the protein, and so the fluorescence intensity of Tb￣(3+) decreased,which is called quenching effect.The quencliing effect is related to the ionic radii of the Ln￣(3+) ions and energy transfer from Tb￣(3+) protein to Ln￣(3+) ions. Based on the ex- perimental results,a schematic of the energy transfer from protein-Tb￣(3+) complex to protein-Ln￣(3+) complex is suggested.展开更多
基金supported by the National Natural Science Foundation of China(grant No.61775065)。
文摘Dynamic light scattering(DLS)is a nondestructive,well-established technique for the size characterization of proteins,nanoparticles,polymers,and colloidal dispersions.However,current DLS techniques are only applied to particle groups of single composition due to the limitation of their inversion algorithm.In this study,we propose a particle size distribution inversion algorithm based on the Tikhnonov regularization method that can be applied to the dual-substance particle mixture.The algorithm retrieves the particle size distributions of two substances,respectively,by taking advantage of their refractive index differences.The simulation results reveal that the algorithm has excellent accuracy and stability when the scattering angle is 30°.Instead of the original identity matrix,the first-order difference matrix and second-order difference matrix are used as the regular matrix when utilizing the Tikhnonov algorithm,which obviously improves the anti-interference,accuracy,and stability of the algorithm.Furthermore,the inversion of particle size distribution is carried out at a 0.01%–1%noise level,which shows that the algorithm has an available antinoise ability.Finally,experimental particle size measurements for a mixture of polystyrene beads and toner particles demonstrate that the proposed algorithm is superior to the traditional Tikhnonov algorithm in applicability and accuracy.
基金Supported by National College Students Innovation and Entrepreneurship Training Program of the Ministry of Education in 2021"Analysis and Research on Current Situation of Demand for Elderly Care Service in the Context of Implementing the Three-child Policy"(202114389021).
文摘With the intensification of population aging and the implementation of the three-child policy,the elderly care pressure of Chinese families continues to rise.Therefore,accelerating the construction of a new intelligent elderly care service model is an important measure to actively respond to population aging,ease the burden of family elderly care and promote high-quality economic development.In view of this,this study analyzed the intelligent elderly care service to explore the relevant countermeasures of the intelligent elderly care service in the context of fewer children.
基金This study was supported by the National Natural Science Foundation of China(No.21573002)Natural Science Funds for Distinguished Young Scholar of Anhui Province(No.1908085J08)the University Annual Scientific Research Plan of Anhui Province(Nos.2022AH050209 and 2022AH010013).
文摘Electrochemical NO reduction reaction(NORR)to NH3 emerges as a fascinating approach to achieve both the migration of NO pollutant and the green synthesis of NH3.In this contribution,within the framework of computational hydrogen model and constant-potential implicit solvent model,the NORR electrocatalyzed by a novel transition-metal-anchored SnOSe armchair nanotube(TM@SnOSe_ANT)was investigated using density functional theory calculations.Through the checking in terms of stability,activity,and selectivity,Sc-and Y@SnOSe_ANTs were screened out from the twenty-five candidates.Considering the effects of pH,solvent environment,as well as applied potential,only Sc@SnOSe_ANT is found to be most promising.The predicted surface area normalized capacitance is 11.4μF/cm^(2),and the highest NORR performance can be achieved at the U_(RHE) of-0.58 V in the acid environment.The high activity originates from the mediate adsorption strength of OH.These findings add a new perspective that the nanotube can be served as a highly promising electrocatalyst towards NORR.
基金supported by the National Natural Science Foundation of China(92057113 and 32122027)the Natural Science Foundation of Guangdong Province(2021A1515012489 and 2022A1515011819)+1 种基金the National Natural Science Foundation of China(82200280)the China Postdoctoral Science Foundation(2022M713573).
文摘Cardiac fibrosis is a pathological response characterized by excessive deposition of fibrous connective tissue within the heart.It typically occurs following cardiac injuries or diseases.However,the lack of suitable models for disease modeling and high-throughput drug discovery has hindered the establishment of an effective treatments for cardiac fibrosis.The emergence and rapid progress of stem-cell and lineage reprogramming technology offer an unprecedented opportunity to develop an improved humanized and patient-specific model for studying cardiac fibrosis,providing a platform for screening potential drugs and synchronously elucidating the underlying molecular mechanisms.Furthermore,reprogramming cardiac fibroblasts into cardiomyocyte-like cells to reduce scar volume and induce myocardial tissue regeneration is a promising approach in treating cardiac fibrosis.In this review,we summarize the current advancements in stem cell technologies applied to study cardiac fibrosis and provide insights for future investigations into its mechanisms,drug discovery as well as therapy method.
基金the National Natural Science Foundation of China(No.81430023)。
文摘To the Editor:Parkinson disease(PD)is the second most common neurodegenerative disorder associated with significant disability and negative impact on quality of life(QoL),affecting 2%to 3%of the population≥65 years of age.^([1])Although the disorder is defined by motor features including asymmetric tremor,bradykinesia,and rigidity,various non-motor features are typically seen,including cognitive impairment,depression,sensory symptoms,autonomic dysfunction,and sleep disturbances.Due to the complexity,PD is challenging to treat.There are currently no effective treatments to prevent or halt the progression of PD.
基金the Start- up Fund for Returned Overseas Scholars from Northeast Normal U niversity,National ScienceFund for Distinguished Young Scholars (No. 30 32 5 0 11) ,Distinguished Young Scholars Fund of Jilin Province(No.2 0 0 30 112 ) ,Excellent Young Teachers
文摘A stably transfected CHO cell line coexpressing G551D-CFTR and iodide-sensitive yellow fluorescent protein mutant EYFP-H148Q-I152L was successfully established and used as assay model to identify small-molecule activators of G551D-CFTR chloride channel from 100000 diverse combinatorial compounds by high throughput screening on a customized Beckman robotic system. A bicyclooctane compound was identified to activate G551D-CFTR chloride channel with high-affinity(K d=1.8 μmol/L). The activity of the bicyclooctane compound is G551D-CFTR-specific, reversible and non-toxic. The G551D-CFTR activator may be useful as a tool to study the mutant G551D-CFTR chloride channel structure and transport properties and as a candidate drug to cure cystic fibrosis caused by G551D-CFTR mutation.
文摘In a permanent magnet synchronous generator(PMSG)system,conversion systems are major points of failure that create expensive and time-consuming problems.Fault detection is usually used to achieve a steady system.This paper presents a full analysis of a PMSG system for wind turbines(WT)and proposes a fault detection method using correlation features.The proposed method is motivated by the balance among the three-phase currents both before and after an opencircuit fault occurs in a converter of the PMSG system.It is unnecessary to analyze the output waveforms of a converter during fault detection.In this study,two correlation features of stator currents,the mean and covariation,are extracted to train an artificial neural network(ANN),thereby enhancing the performance of the proposed method under different wind speed conditions.Moreover,additional sensors and the collection of a massive amount of data are not required.Model simulations of an ideal inverter and a PMSG system are conducted using PSCAD software.The simulation results show that the proposed method can detect the locations of faulty switches with a diagnostic rate greater than 99.4%for the ideal inverter,and the PMSG drives settings at different wind speeds.
基金JAC acknowledges support from projects MTM2011-27739-C04-02,2009-SGR-345 from Agencia de Gestio d’Ajuts Universitaris i de Recerca-Generalitat de Catalunya,and the Royal Society through a Wolfson Research Merit AwardJAC and YH were supported by Engineering and Physical Sciences Research Council(UK)grant number EP/K008404/1+1 种基金The work of AC was supported in part by the NSF Grant DMS-1115682The authors also acknowledge the support by NSF RNMS grant DMS-1107444.
文摘We propose a positivity preserving entropy decreasing finite volume scheme for nonlinear nonlocal equations with a gradient flow structure.These properties allow for accurate computations of stationary states and long-time asymptotics demonstrated by suitably chosen test cases in which these features of the scheme are essential.The proposed scheme is able to cope with non-smooth stationary states,different time scales including metastability,as well as concentrations and self-similar behavior induced by singular nonlocal kernels.We use the scheme to explore properties of these equations beyond their present theoretical knowledge.
文摘The drawbacks of the traditional multi-hop structure of wireless sensor networks(WSNS)are susceptible to reflection,scattering and diffraction,serious attenuation of signal intensity and phase deviation due to various obstacles in cultivated land environment and mountains.In this paper,the wireless signal intensity is measured and curve fitting is done respectively in both open environment and obstacle-environment with both sending and receiving height of 0 m,1 m,and 2 m.It is found out that packet loss probability is too high when an obstacle exists.In such a case,unmanned aerial vehicle(UAV)is introduced to activate terrestrial nodes and operation mechanism of distributed storage.Experimental results show that both ground-to-air barrier-free communication and communication with obstacles can greatly reduce the energy consumption of each node and packet loss probability,thus greatly improving the reliability of UAV-WSN system.
文摘Temporal changes of dominant microbial populations in groundwater in response to the leachate from Shanghai Laogang Landfill were investigated. Concentrations of dissolved redox relevant species in groundwater suggested that the dominating redox process had changed from denitrification to methane production/sulfate reduction due to landfilling. Dominant microbial populations were determined using restriction fragment length polymorphism(RFLP) analyses of 16S rRNA gene libraries, which were further studied by sequencing and phylogenetic analyses. The results indicated that obvious shifts of dominant microbial populations had occurred in groundwater in response to the pollution of leachate. The closest relatives of some dominant clones are accordant with the dominating redox processes determined by hydrochemical analyses, based on the GenBank's indications on the ability to perform redox reactions.
文摘Aim To develop a sensitive competitive ELBA for the determination of biotinin transformed yeast culture media. Methods The ELBA plate was firstly coated with Mycoplasmahyopneumoniae, and then successively incubated with rabbit anti-Mycoplasma hyopneumoniae serum andgoat anti-rabbit IgG-biotin to form the solid biotin, which competed with the biotin in the solution(standard or sample) for the limited streptavidin-horse radish peroxidase conjugate. The standardcalibration curve for biotin analysis was constructed in the range of 50 - 2000 ng·L^(-1). ResultsThe detection limit for biotin was found to be 83 ng·L^(-1), which was about 1000 times lower thanthe lowest determination concentration in the reported ELISA for biotin analysis. The relativestandard deviations for the spiked samples at biotin concentrations of 200 ng·L^(-1), 500ng·L^(-1), and 1000 ng·L^(-1) were 24.87%, 6.15% , and 7.86% , respectively, with the averagerecovery of 101.13% . The wild yeast and its sixty-three transformed yeast culture media wereapplied to the developed ELBA for the determination of biotin. It was found that the biotinconcentrations in more than 85% of the tested samples were enhanced with different increase factorsafter transformation. Conclusion Utilization of Mycoplasma hyopneumoniae as the coating proteinimproves the precision and accuracy of the ELBA assay, which might be used for the biotin assay inother media.
文摘Characteristic set method of polynomial equation solving has been widely spread and its implementation in software has been urged to consider in recent years. Several packages for the method are implemented in some computer algebra systems, such as REDUCE and Maple. In order to improve the efficiency of the method, we have developed a computer algebra system ″ELIMINO″ written in C language and implemented on Linux operation system on a PC. The authors wish to share with the reader the knowledge and experiences about the design and development of software package of the characteristic set method.
基金The authors thank the financial support from the Critical Patented Projects in the Control and Management of the National Polluted Water Bodies （No. 2008ZX07317-02-03E）, the Key Science Research Projects of Ministry of Education of China and the Provincial Natural Science Foundation of Guangxi （No. Guikegung 0992008-3, Guikeqing 0640070）.
文摘To evaluate possible use of microwave- enhanced H2O2-based （MW/H2O2） process to degrade trace nitrobenzene （NB） in water, a series of batch experiments were conducted. The results showed that 2450MHz microwave irradiation significantly enhanced oxidative decomposition of nitrobenzene （NB） in a H2O2 system. About 90% NB was degraded by the MW/H2O2 process in 30 min. Moreover, the MW/H2O2 process could enhanced the oxidative degradation of NB even at relatively low temperature （50℃）. When the initial concentration of NB was 300gg/L, the optimum ratio of H2O2 to NB and MW power were 70 and 300W respectively. The presence of humic acid significantly increased H2O2 dosage. The ultraviolet absorbance at 254 nm （UV254） indicated degradation of NB was stepwise and some intermediates were produced. The gas chromatography-mass spectrometric （GC-MS） analysis showed that main intermediates were nitrophenolic and carbonyl compounds.
文摘A thiazolidinone CFTR inhibitor(CFTR_ inh-172 ) was synthesized by a three-step procedure with trifluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally by means of 1H NMR and functionally in a CFTR-expressing cell line FRT/hCFTR/EYFP-H148Q by both fluorescent and electrophysiological methods. A large amount(100 g) of high-quality small molecule thiazolidinone CFTR chloride channel inhibitor,CFTR_ inh-172 ,can be produced with this simple three-step synthetic procedure. The structure of the final product 2-thioxo-3-(3-trifluromethylphenyl)-5-[4-carboxyphenyl- methylene]-4-thiazolidinone was confirmed by 1H NMR. The overall yield was 58% with a purity over 99% as analyzed by HPLC. The synthesized CFTR_ inh-172 specifically inhibited CFTR chloride channel function in a cell-based fluorescence assay( K _d≈1.5 μmol/L) and in a Ussing chamber-based short-circuit current assay( K _d≈0.2 μmol/L),indicating better quality than that of the commercial combinatorial compound. The synthesized inhibitor is nontoxic to cultured cells at a high concentration and to mouse at a high dose. The synthetic procedure developed here can be used to produce a large amount of the high-quality CFTR_ inh-172 suitable for antidiarrheal studies and for creation of cystic fibrosis models in large animals. The procedure can be used to synthesize radiolabled CFTR_ inh-172 for in vivo pharmacokinetics studies.
基金This research was financially supported by FDCT NO.005/2018/A1also supported by Guangdong Provincial Innovation and Entrepreneurship Training Program Project No.201713719017College Students Innovation Training Program held by Guangdong university of Science and Technology Nos.1711034,1711080,and No.1711088.
文摘Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan City.GeoDa software was used to eliminate the insignificant factors by stepwise regression analysis;NORM software was adopted to construct the multiple imputation models;EM algorithm and the augmentation algorithm were applied to fit multiple linear regression equations to construct five different filling datasets.Statistical analysis is performed on the imputation data set in order to calculate the mean and variance of each data set,and the weight is determined according to the differences.Finally,comprehensive integration is implemented to achieve the imputation expression of missing values.The results showed that in the three missing cases where the PRICE variable was missing and the deletion rate was 5%,the PRICE variable was missing and the deletion rate was 10%,and the PRICE variable and the CBD variable were both missing.The new method compared to the traditional multiple filling methods of true value closer ratio is 75%to 25%,62.5%to 37.5%,100%to 0%.Therefore,the new method is obviously better than the traditional multiple imputation methods,and the missing value data estimated by the new method bears certain reference value.
文摘he interaction of lanthanide (Ln￣(3+))ions with trchosanthin(TCS)was investi-gated using Tb￣(3+) as fluorescent probe. The metal-binding sites of the protein were probed by means of adding the Tb￣(3+) into the protein solutions. If other Ln￣(3+) ions exist in the Tb￣(3+) protein complex system, they would compete against Tb￣(3+) in the binding sites of the protein, and so the fluorescence intensity of Tb￣(3+) decreased,which is called quenching effect.The quencliing effect is related to the ionic radii of the Ln￣(3+) ions and energy transfer from Tb￣(3+) protein to Ln￣(3+) ions. Based on the ex- perimental results,a schematic of the energy transfer from protein-Tb￣(3+) complex to protein-Ln￣(3+) complex is suggested.
