[ Objective] The aim of this study was to provide the reference for the artificial breeding of aquatic animals. [ Method] Amoeba discoides and Trichodina were treated by neutral red solution with different concentrati...[ Objective] The aim of this study was to provide the reference for the artificial breeding of aquatic animals. [ Method] Amoeba discoides and Trichodina were treated by neutral red solution with different concentrations to observe the physiological activities of organelles in their death processes. Effects of neutral red solution on the growth of common aquatic animals such as Paramecium caudatum, Euglena viridis and Brachionus plicatilis were analyzed, and the specific lethal mechanism of trace neutral red to A. discoides and Trichodina was also preliminarily studied. [ Re- suit] The neutral red solution at a concentration of 0.5 mg/L damaged the physiological function of contractile vacuole in Trichodina and also had the specific lethal effect on Tdchodina, but it had no effect on the growth and reproduction of non-parasitic protozoa and B. p/icatilis. Neutral red so- lution with certain concentration led to disorder of the physiological functions of A. discoides, such as assimilation and rejection, which was a main factor that caused the death of A. discoides. [ Conclusion] With the advantages such as targeting, safety and easiness to be oxidized and decom- posed, neutral red is an ideal drug for treating the diseases caused by A. discoides and Trichodina, and its suitable concentration is 0. 5 mg/L.展开更多
Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated w...Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated with a hematoporphyrin derivative (HPD) by using carbodiimide. The qualitative analysis of this conjugate showed that the amount of free HPD was negligible and there were no IgG aggregates among the conjugates. The conjugate retained both the antibody and photochemical activity of HPD.In vitro, the phototoxic effect of this HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The quality of selective photocytotoxicity was proven by the greater cytotoxi-city this conjugate showed than that of corresponding normal mouse IgG (NIgG) conjugated with HPD. It showed less cytotoxicity to colon cancer cell line B-80 (negative reaction to MoAb BB4.3) than to BGC825. Moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody, but not by another MoAb 3G9, which combines with BGC823 at different binding sites from MoAb BB4.3.Nude mice inoculated with 2 × 10- BGC823 cells were given HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS, respectively then exposed to light. Four out of six animals treated with the HPD-BB4.3 conjugate remained tumor-free for a long period. Although two developed tumors, there was a significant difference between the HPD-BB4.3-treated group and all the control groups in tumor induction time, tumor growth rate, and survival time (p<0.001). The HPD-BB4.3 conjugate inhibited the growth of established tumors by more than 40% in comparison with control groups (p<0.05).展开更多
Objective To investigate the influence of m4-1BBL on anti-tumor effects induced by truncated human prostate specific membrane antigen ( tPSMA ) gene in mice. Methods A eukaryotic expression plasmid encoding tPSMA and ...Objective To investigate the influence of m4-1BBL on anti-tumor effects induced by truncated human prostate specific membrane antigen ( tPSMA ) gene in mice. Methods A eukaryotic expression plasmid encoding tPSMA and m4-1BBL ( pDC316-tPSMA-IRES m4-1BBL) ,pDC316-tPSMA and pDC316 were constructed.展开更多
Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs (abbreviated XBAYs) were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical...Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs (abbreviated XBAYs) were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical shifts (δH(CH=N)) and 13C NMR chemical shifts (δc(CH=N)) of the CH=N bridging group from di-substituted to multi-substituted XBAYs was made based on a total of 182 samples of XBAYs, together with the NMR data of other 129 samples of di-substituted XBAYs quoted from literatures. The results show thatthe substituent specific cross-interaction effect parameter (△(∑σ)2) plays an important role in quantifying the δc(CH=N) values of XBAYs, but it is negligible for quantifying the δH (CH=N) values; the other substituent parameters also present different influences on the δc (CH=N) and (δH (CH=N). On the whole, the contributions of X and Y to the δc (CH=N) of XBAYs are balanced, but the δH(CH=N) values of XBAYs mainly rely on the contributions of X.展开更多
At present, the specificity of meridians and acupoints has been studied using functional brain imaging techniques from many standpoints, including meridians, acupoints, and sham acupoints, as well as different meridia...At present, the specificity of meridians and acupoints has been studied using functional brain imaging techniques from many standpoints, including meridians, acupoints, and sham acupoints, as well as different meridians and acupoints, coordination of acupoints, and factors influencing meridian and acupoint specificity Preliminary experimental data have demonstrated that acupuncture at meridians and acupoints is specific with regard to brain neural information. However, research findings are contradictory, which may be related to brain functional complexity, resolution of functional brain imaging techniques, and experimental design. Future studies should further improve study method, and should strictly control experimental conditions to better analyze experimental data and acquire more beneficial data. Because of its many advantages, the functional brain imaging technique is a promising method for studying meridian and acupoint specificity.展开更多
Objective:To observe the specific effects of acupuncture in middle-aged and older patients with chronic nonspecific low back pain(CNSLBP).Methods:Sixty-six patients with CNSLBP were randomized into the acupuncture or ...Objective:To observe the specific effects of acupuncture in middle-aged and older patients with chronic nonspecific low back pain(CNSLBP).Methods:Sixty-six patients with CNSLBP were randomized into the acupuncture or sham acupuncture groups(n=33).In the acupuncture group,penetrating acupuncture with a long needle was delivered at Ashi points(painful/sensitive points),and the needles were manipulated by rotating technique after deqi till patients felt distending pain.The needles were retained in place for 30 min.Acupuncture was given three times per week for 4 weeks.In the sham acupuncture group,shallow needling was performed at non-meridian,non-acupoint,non-painful,and non-sensitive points.The needle retention and duration of treatment were the same as those of the acupuncture group before treatment,after the first intervention,after the whole treatment,and in follow-up visit(4 weeks after the whole treatment).The scores of the visual analog scale(VAS)for pain,range of movement(ROM)of the spine,and simplified Oswestry Dysfunction Index(ODI)were observed separately.Results:Compared to the outcomes before treatment,the VAS score,spinal ROM,and simplified ODI score were lower after the first intervention,after treatment,and in follow-up visits in the acupuncture group,indicating the statistical significance(P<0.05).When compared with the sham acupuncture group,the VAS score,spinal ROM,and simplified ODI score were significantly lower in the acupuncture group after the first intervention,after treatment,and in follow-up visit(P<0.05).The total effective rate was 90.9%in the acupuncture group,which was significantly higher than that(75.76%)in the sham acupuncturegroup(P<0.05).Conclusion:Acupuncture has a specific effect on CNSLBP in middle-aged and older patients and a superior effect on immediate analgesia.展开更多
Rayleigh-Taylor(RT)instability widely exists in nature and engineering fields.How to better understand the physical mechanism of RT instability is of great theoretical significance and practical value.At present,abund...Rayleigh-Taylor(RT)instability widely exists in nature and engineering fields.How to better understand the physical mechanism of RT instability is of great theoretical significance and practical value.At present,abundant results of RT instability have been obtained by traditional macroscopic methods.However,research on the thermodynamic non-equilibrium(TNE)effects in the process of system evolution is relatively scarce.In this paper,the discrete Boltzmann method based on non-equilibrium statistical physics is utilized to study the effects of the specific heat ratio on compressible RT instability.The evolution process of the compressible RT system with different specific heat ratios can be analyzed by the temperature gradient and the proportion of the non-equilibrium region.Firstly,as a result of the competition between the macroscopic magnitude gradient and the non-equilibrium region,the average TNE intensity first increases and then reduces,and it increases with the specific heat ratio decreasing;the specific heat ratio has the same effect on the global strength of the viscous stress tensor.Secondly,the moment when the total temperature gradient in y direction deviates from the fixed value can be regarded as a physical criterion for judging the formation of the vortex structure.Thirdly,under the competition between the temperature gradients and the contact area of the two fluids,the average intensity of the non-equilibrium quantity related to the heat flux shows diversity,and the influence of the specific heat ratio is also quite remarkable.展开更多
Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is e...Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.展开更多
This paper studies the effective properties of multi-phase thermoelastic composites. Based on the Helmholtz free energy and the Gibbs free energy of individual phases, the effective elastic tensor, thermal-expansion t...This paper studies the effective properties of multi-phase thermoelastic composites. Based on the Helmholtz free energy and the Gibbs free energy of individual phases, the effective elastic tensor, thermal-expansion tensor, and specific heats of the multi-phase composites are derived by means of the volume average of free-energies of these phases. Particular emphasis is placed on the derivation of new analytical expressions of effective specific heats at constant-strain and constant-stress situations, in which a modified Eshelby's micromechanics theory is developed and the interaction between inclusions is considered. As an illustrative example, the analytical expression of the effective specific heat for a three-phase thermoelastic composite is presented.展开更多
The catalytic activity of two common bacterial enzymes, lactate dehydrogenase (LDH) and cytochrome c oxidase (COX) from Escherichia coli was examined following bacterial exposure to microwave (MW) radiation unde...The catalytic activity of two common bacterial enzymes, lactate dehydrogenase (LDH) and cytochrome c oxidase (COX) from Escherichia coli was examined following bacterial exposure to microwave (MW) radiation under well-defined experimental conditions. The experiments were conducted in a specialized microwave processing apparatus, with an exposure frequency of 18 GHz, and a temperature profile that was restricted to below 40℃ to avoid thermal degradation of the bacteria. The absorbed power was calculated to be 1,500 kW/m3 and the electric field was determined to be 300 Wm. Both values were theoretically confirmed using Computer Simulation Technology (CST) Microwave Studio 3D Electromagnetic Stimulation Software. Results showed that the activity of both enzymes was increased following MW radiation compared to negative controls and thermally treated samples subjected to similar temperature profiles. It is suggested that the increase in COX and LDH enzyme activity could not be explained by conventional heating alone, but was rather a result of micro-thermal effects that incorporated 'undetectable' thermal mechanisms.展开更多
Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was a...Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was applied as a new simplified strategy to both recognize and inhibit a single bacteria species of Staphylococcus aureus(S. aureus) simultaneously. The probes are composed of peptides and Au clusters. Moreover, the peptides specifically target S. aureus cells and the Au clusters provide fluorescent imaging and have an antibacterial effect. These new probes enable the simultaneous specific detection and effective destruction S. aureus cells in situ.展开更多
In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction(ASR), and to identify the mechanism of suppressing ASR by this powders, ...In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction(ASR), and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m^2/kg to 860 m^2/kg were studied. The experimental results showed that incorporation of 40wt% reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m^2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of fl ame photometry, Fourier transform infrared spectroscopy(FT-IR) and thermo gravimetric analysis(TG), the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.展开更多
Different acupuncture-moxibustion therapies can produce different clinical effects, that is, the effect has specificity, which is significantly important in obtaining acupuncture-moxibustion efficacy. In this study, t...Different acupuncture-moxibustion therapies can produce different clinical effects, that is, the effect has specificity, which is significantly important in obtaining acupuncture-moxibustion efficacy. In this study, the clinical application laws of fire needle, acupoint injection, catgut embedment, acupoint application, moxibustion therapy and filiform needle acupuncture were summarized in the aspects of category of disease, efficacy and related prescriptions (such as medication and acupoint selection) based on the result of data mining, and the general applicable categories of disease of acupuncture-moxibustion treatment methods were further screened, so as to guide the clinical application and give play to the best efficacy.展开更多
In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive stati...In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.展开更多
Objective: To investigate the specificity of the effects of electroacupuncture (EA) at different acupoints on gastric functional activity and gastric blood flow after colorectal distension (CRD) in the rat. Methods: F...Objective: To investigate the specificity of the effects of electroacupuncture (EA) at different acupoints on gastric functional activity and gastric blood flow after colorectal distension (CRD) in the rat. Methods: Fifty Wistar rats were randomly divided into 5 groups: a control group, a Zusanli group, a non-point group, a Taichong group and a Neiguan group. Rats were anesthetized after 18 h of fasting, and a rat model of nociceptive blood pressure elevation and abnormal electrogastrogram (EGG) and gastric tension (GT) was prepared by gasbag-induced CRD. EA was given bilaterally, and its effects on gastric blood flow (GBF) of the arcus vasculosi of the greater omentum, blood pressure, EGG fast wave properties, and gastric smooth muscle tension (GT) were quantified. Results: CRD induced an increase in blood pressure that was significantly inhibited by EA at all points (all P<0.05), and the inhibitory effects were greater in the Zusanli and Neiguan groups compared to the non-point group (both P<0.05). CRD also caused reductions in GT and GBF, and in the amplitude, frequency and duration of EGG waves (all P<0.05). These effects were also reversed by EA. The effects of EA on EGG wave amplitude, GT, and GBF were superior in the Zusanli group compared to the Taichong group, Neiguan group, and the non-point group. Conclusion: EA significantly counteracted CRD-induced changes in blood pressure, GBF, EGG, and GT. The effects of stimulation at Zusanli (ST 36) were significantly greater compared to other points, indicating relative specificity of this acupoint.展开更多
The use of building materials containing naturally occurring radionuclides such as^40K,^238U,^232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of model...The use of building materials containing naturally occurring radionuclides such as^40K,^238U,^232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of models are constructed to calculate the specific effective dose rates(the effective dose rate per Bq/kg of ^40K, the ^238U series,and the ^232Th series) imposed on residents by building materials with the MCNPX code. The effect of chemical composition, position concerned in the room and thickness as well as density of material is analyzed. In order to facilitate more precise assessment of indoor external dose due to gamma-emitting radionuclides in building materials,three regressive expressions are proposed and validated by measured data to calculate specific effective rates for40 K,the238U series and the232 Th series, respectively.展开更多
基金supported by 863 Project (2005AA601010-05)Student Innovative Experiment Fund of Shenzhen University
文摘[ Objective] The aim of this study was to provide the reference for the artificial breeding of aquatic animals. [ Method] Amoeba discoides and Trichodina were treated by neutral red solution with different concentrations to observe the physiological activities of organelles in their death processes. Effects of neutral red solution on the growth of common aquatic animals such as Paramecium caudatum, Euglena viridis and Brachionus plicatilis were analyzed, and the specific lethal mechanism of trace neutral red to A. discoides and Trichodina was also preliminarily studied. [ Re- suit] The neutral red solution at a concentration of 0.5 mg/L damaged the physiological function of contractile vacuole in Trichodina and also had the specific lethal effect on Tdchodina, but it had no effect on the growth and reproduction of non-parasitic protozoa and B. p/icatilis. Neutral red so- lution with certain concentration led to disorder of the physiological functions of A. discoides, such as assimilation and rejection, which was a main factor that caused the death of A. discoides. [ Conclusion] With the advantages such as targeting, safety and easiness to be oxidized and decom- posed, neutral red is an ideal drug for treating the diseases caused by A. discoides and Trichodina, and its suitable concentration is 0. 5 mg/L.
文摘Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated with a hematoporphyrin derivative (HPD) by using carbodiimide. The qualitative analysis of this conjugate showed that the amount of free HPD was negligible and there were no IgG aggregates among the conjugates. The conjugate retained both the antibody and photochemical activity of HPD.In vitro, the phototoxic effect of this HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The quality of selective photocytotoxicity was proven by the greater cytotoxi-city this conjugate showed than that of corresponding normal mouse IgG (NIgG) conjugated with HPD. It showed less cytotoxicity to colon cancer cell line B-80 (negative reaction to MoAb BB4.3) than to BGC825. Moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody, but not by another MoAb 3G9, which combines with BGC823 at different binding sites from MoAb BB4.3.Nude mice inoculated with 2 × 10- BGC823 cells were given HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS, respectively then exposed to light. Four out of six animals treated with the HPD-BB4.3 conjugate remained tumor-free for a long period. Although two developed tumors, there was a significant difference between the HPD-BB4.3-treated group and all the control groups in tumor induction time, tumor growth rate, and survival time (p<0.001). The HPD-BB4.3 conjugate inhibited the growth of established tumors by more than 40% in comparison with control groups (p<0.05).
文摘Objective To investigate the influence of m4-1BBL on anti-tumor effects induced by truncated human prostate specific membrane antigen ( tPSMA ) gene in mice. Methods A eukaryotic expression plasmid encoding tPSMA and m4-1BBL ( pDC316-tPSMA-IRES m4-1BBL) ,pDC316-tPSMA and pDC316 were constructed.
基金supported by the National Natural Science Foundation of China(No.21672058 and No.21272063)
文摘Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs (abbreviated XBAYs) were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical shifts (δH(CH=N)) and 13C NMR chemical shifts (δc(CH=N)) of the CH=N bridging group from di-substituted to multi-substituted XBAYs was made based on a total of 182 samples of XBAYs, together with the NMR data of other 129 samples of di-substituted XBAYs quoted from literatures. The results show thatthe substituent specific cross-interaction effect parameter (△(∑σ)2) plays an important role in quantifying the δc(CH=N) values of XBAYs, but it is negligible for quantifying the δH (CH=N) values; the other substituent parameters also present different influences on the δc (CH=N) and (δH (CH=N). On the whole, the contributions of X and Y to the δc (CH=N) of XBAYs are balanced, but the δH(CH=N) values of XBAYs mainly rely on the contributions of X.
基金Major State Basic Research Development Program of China (973 Program), No.2006CB504501
文摘At present, the specificity of meridians and acupoints has been studied using functional brain imaging techniques from many standpoints, including meridians, acupoints, and sham acupoints, as well as different meridians and acupoints, coordination of acupoints, and factors influencing meridian and acupoint specificity Preliminary experimental data have demonstrated that acupuncture at meridians and acupoints is specific with regard to brain neural information. However, research findings are contradictory, which may be related to brain functional complexity, resolution of functional brain imaging techniques, and experimental design. Future studies should further improve study method, and should strictly control experimental conditions to better analyze experimental data and acquire more beneficial data. Because of its many advantages, the functional brain imaging technique is a promising method for studying meridian and acupoint specificity.
基金Supported by the Bejing Municipal Administration of Hospitals Incubation Program:PZ2022012National Famous Traditional Chinese Medicine Expert Inheritance Studio Construction Project:Guozhongyao Renjiaohan[2022]No.75Construction Project for the Inheritance of National Famous Traditional Chinese Medicine Experts in the Seventh Batch:Guozhongyao Renjiao Han[2022]No.76.
文摘Objective:To observe the specific effects of acupuncture in middle-aged and older patients with chronic nonspecific low back pain(CNSLBP).Methods:Sixty-six patients with CNSLBP were randomized into the acupuncture or sham acupuncture groups(n=33).In the acupuncture group,penetrating acupuncture with a long needle was delivered at Ashi points(painful/sensitive points),and the needles were manipulated by rotating technique after deqi till patients felt distending pain.The needles were retained in place for 30 min.Acupuncture was given three times per week for 4 weeks.In the sham acupuncture group,shallow needling was performed at non-meridian,non-acupoint,non-painful,and non-sensitive points.The needle retention and duration of treatment were the same as those of the acupuncture group before treatment,after the first intervention,after the whole treatment,and in follow-up visit(4 weeks after the whole treatment).The scores of the visual analog scale(VAS)for pain,range of movement(ROM)of the spine,and simplified Oswestry Dysfunction Index(ODI)were observed separately.Results:Compared to the outcomes before treatment,the VAS score,spinal ROM,and simplified ODI score were lower after the first intervention,after treatment,and in follow-up visits in the acupuncture group,indicating the statistical significance(P<0.05).When compared with the sham acupuncture group,the VAS score,spinal ROM,and simplified ODI score were significantly lower in the acupuncture group after the first intervention,after treatment,and in follow-up visit(P<0.05).The total effective rate was 90.9%in the acupuncture group,which was significantly higher than that(75.76%)in the sham acupuncturegroup(P<0.05).Conclusion:Acupuncture has a specific effect on CNSLBP in middle-aged and older patients and a superior effect on immediate analgesia.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51806116 and 11875001)the Natural Science Foundation of Fujian Province(Grant No.2018J01654).
文摘Rayleigh-Taylor(RT)instability widely exists in nature and engineering fields.How to better understand the physical mechanism of RT instability is of great theoretical significance and practical value.At present,abundant results of RT instability have been obtained by traditional macroscopic methods.However,research on the thermodynamic non-equilibrium(TNE)effects in the process of system evolution is relatively scarce.In this paper,the discrete Boltzmann method based on non-equilibrium statistical physics is utilized to study the effects of the specific heat ratio on compressible RT instability.The evolution process of the compressible RT system with different specific heat ratios can be analyzed by the temperature gradient and the proportion of the non-equilibrium region.Firstly,as a result of the competition between the macroscopic magnitude gradient and the non-equilibrium region,the average TNE intensity first increases and then reduces,and it increases with the specific heat ratio decreasing;the specific heat ratio has the same effect on the global strength of the viscous stress tensor.Secondly,the moment when the total temperature gradient in y direction deviates from the fixed value can be regarded as a physical criterion for judging the formation of the vortex structure.Thirdly,under the competition between the temperature gradients and the contact area of the two fluids,the average intensity of the non-equilibrium quantity related to the heat flux shows diversity,and the influence of the specific heat ratio is also quite remarkable.
基金the National Natural Science Foundation of China(Nos.21873091,52033001 and 22103002)the Youth Innovation Promotion Association of CAS(No.Y201769)+1 种基金the National Synchrotron Radiation Laboratory(No.UN2018LHJJ)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.
基金Project supported by the National Natural Science Foundation of China (Nos. 10602002 and 10932001)the Major State Basic Research Development Program (No. 2010CB731503)
文摘This paper studies the effective properties of multi-phase thermoelastic composites. Based on the Helmholtz free energy and the Gibbs free energy of individual phases, the effective elastic tensor, thermal-expansion tensor, and specific heats of the multi-phase composites are derived by means of the volume average of free-energies of these phases. Particular emphasis is placed on the derivation of new analytical expressions of effective specific heats at constant-strain and constant-stress situations, in which a modified Eshelby's micromechanics theory is developed and the interaction between inclusions is considered. As an illustrative example, the analytical expression of the effective specific heat for a three-phase thermoelastic composite is presented.
文摘The catalytic activity of two common bacterial enzymes, lactate dehydrogenase (LDH) and cytochrome c oxidase (COX) from Escherichia coli was examined following bacterial exposure to microwave (MW) radiation under well-defined experimental conditions. The experiments were conducted in a specialized microwave processing apparatus, with an exposure frequency of 18 GHz, and a temperature profile that was restricted to below 40℃ to avoid thermal degradation of the bacteria. The absorbed power was calculated to be 1,500 kW/m3 and the electric field was determined to be 300 Wm. Both values were theoretically confirmed using Computer Simulation Technology (CST) Microwave Studio 3D Electromagnetic Stimulation Software. Results showed that the activity of both enzymes was increased following MW radiation compared to negative controls and thermally treated samples subjected to similar temperature profiles. It is suggested that the increase in COX and LDH enzyme activity could not be explained by conventional heating alone, but was rather a result of micro-thermal effects that incorporated 'undetectable' thermal mechanisms.
基金supported by the National Natural Science Foundation of China(21727817,21390414,21425522,51571185)Beijing Science and Technology Commission Special Project for Frontier Technology in Life Sciences(Z171100000417008)
文摘Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was applied as a new simplified strategy to both recognize and inhibit a single bacteria species of Staphylococcus aureus(S. aureus) simultaneously. The probes are composed of peptides and Au clusters. Moreover, the peptides specifically target S. aureus cells and the Au clusters provide fluorescent imaging and have an antibacterial effect. These new probes enable the simultaneous specific detection and effective destruction S. aureus cells in situ.
基金Funded partly by the the National 973 Program of China(No.2013CB035901)the National Natural Science Foundation of China(No.51379163)
文摘In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction(ASR), and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m^2/kg to 860 m^2/kg were studied. The experimental results showed that incorporation of 40wt% reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m^2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of fl ame photometry, Fourier transform infrared spectroscopy(FT-IR) and thermo gravimetric analysis(TG), the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.
基金National Natural Science Foundation of China:81072883,81173342,81473773Scientific Research Project of Hebei Education Department:Z 2014145Planned Project of Young Talents in Colleges and Universities in Hebei Province:BJ 2014047
文摘Different acupuncture-moxibustion therapies can produce different clinical effects, that is, the effect has specificity, which is significantly important in obtaining acupuncture-moxibustion efficacy. In this study, the clinical application laws of fire needle, acupoint injection, catgut embedment, acupoint application, moxibustion therapy and filiform needle acupuncture were summarized in the aspects of category of disease, efficacy and related prescriptions (such as medication and acupoint selection) based on the result of data mining, and the general applicable categories of disease of acupuncture-moxibustion treatment methods were further screened, so as to guide the clinical application and give play to the best efficacy.
基金financially supported by the National Natural Science Foundation of China(Nos.21873091,21622405,21574121 and 52033001)the Youth Innovation Promotion Association of CAS(No.Y201769)+1 种基金the National Synchrotron Radiation Laboratory(No.UN2018LHJJ)the Fundamental Research Funds for the Central Universities(No.WK2480000007)。
文摘In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.
基金supported by TCM Item of National Key Basic Study (2005CB523306, 2006CB504506 2007CB512505)the National Natural Science Foundation of China (30973796, 90709031)
文摘Objective: To investigate the specificity of the effects of electroacupuncture (EA) at different acupoints on gastric functional activity and gastric blood flow after colorectal distension (CRD) in the rat. Methods: Fifty Wistar rats were randomly divided into 5 groups: a control group, a Zusanli group, a non-point group, a Taichong group and a Neiguan group. Rats were anesthetized after 18 h of fasting, and a rat model of nociceptive blood pressure elevation and abnormal electrogastrogram (EGG) and gastric tension (GT) was prepared by gasbag-induced CRD. EA was given bilaterally, and its effects on gastric blood flow (GBF) of the arcus vasculosi of the greater omentum, blood pressure, EGG fast wave properties, and gastric smooth muscle tension (GT) were quantified. Results: CRD induced an increase in blood pressure that was significantly inhibited by EA at all points (all P<0.05), and the inhibitory effects were greater in the Zusanli and Neiguan groups compared to the non-point group (both P<0.05). CRD also caused reductions in GT and GBF, and in the amplitude, frequency and duration of EGG waves (all P<0.05). These effects were also reversed by EA. The effects of EA on EGG wave amplitude, GT, and GBF were superior in the Zusanli group compared to the Taichong group, Neiguan group, and the non-point group. Conclusion: EA significantly counteracted CRD-induced changes in blood pressure, GBF, EGG, and GT. The effects of stimulation at Zusanli (ST 36) were significantly greater compared to other points, indicating relative specificity of this acupoint.
基金Supported by Special Social Commonweal Research for Scientific Research Institutions by Ministry of Science,China(2005DIB1J087)
文摘The use of building materials containing naturally occurring radionuclides such as^40K,^238U,^232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of models are constructed to calculate the specific effective dose rates(the effective dose rate per Bq/kg of ^40K, the ^238U series,and the ^232Th series) imposed on residents by building materials with the MCNPX code. The effect of chemical composition, position concerned in the room and thickness as well as density of material is analyzed. In order to facilitate more precise assessment of indoor external dose due to gamma-emitting radionuclides in building materials,three regressive expressions are proposed and validated by measured data to calculate specific effective rates for40 K,the238U series and the232 Th series, respectively.