Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic me...Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.展开更多
High soda content in fine alumina trihydrate（ATH） limits its application and increases the soda consumption. The variation of soda content in the fine ATH by seeded precipitation was determined by detection of elect...High soda content in fine alumina trihydrate（ATH） limits its application and increases the soda consumption. The variation of soda content in the fine ATH by seeded precipitation was determined by detection of electric conductivity of solution, soda content in ATH, measurement of particle size distribution and microscopic analysis. The results show that high concentration of sodium aluminate solution, ground circulative seed, low temperature or fast initial precipitation rate increases the soda content in ATH. Soda mainly exists in lattice soda and less soda in desilication product （DSP） exists in the fine ATH precipitated from sodium aluminate solution with concentration of Al2O3 （ρAl2O3） more than 160 g/L and mass ratio of alumina to silica （μSiO2） of 400, and lattice soda decreases with increasing initial precipitation temperature, aging seed, and low precipitation rate and precipitation time. Results also imply that -＋ 4）Na Al（OH ion-pair influences lattice soda content in ATH on the basis of electric conductivity variation.展开更多
The surface properties of superfine alumina trihydrate （ATH） after surface modification were studied by measuring the contact angle, active ratio, oil adsorption, total organic carbon, adsorption ratio, and Fourier ...The surface properties of superfine alumina trihydrate （ATH） after surface modification were studied by measuring the contact angle, active ratio, oil adsorption, total organic carbon, adsorption ratio, and Fourier transform infrared （FTIR） spectrum. The contact angle increased initially and then slowly decreased with an increase of the amount of stearic acid. However, the surface flee energy decreased ini- tially and then increased. Surface modification with stearic acid or sodium stearate can benefit from elevating temperature. The base surface tension component and the free energy of Lewis acid-base both declined sharply following the surface modification. Excess stearic acid was physically adsorbed in the form of multilayer adsorption, and an interaction between oxygen on the ATH surface and hydroxyl in stearic acid was subsequently determined. Our results further indicated that the contact angle and adsorption ratio can be used as control indicators for surface modification compared with active ratio, oil adsorption and total organic carbon.展开更多
The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent compositio...The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent composition and temperature on solubility of meropenem trihydrate were discussed.To extend the applicability of the solubility data,experimental solubility data in two kinds of binary solvent mixtures were correlated by the Apelblat equation and NIBS/Redlich–Kister model.It was found that the two models could satisfactorily correlate the experimental data and the Apelblat equation could give better correlation results.展开更多
Herein,conductivity measurements have been carried out to explore the interaction between cetyltrimethylammonium bromide(CTAB,a cationic surfactant) and antibiotic drug(cefixime trihydrate(CMT)) in water and also in o...Herein,conductivity measurements have been carried out to explore the interaction between cetyltrimethylammonium bromide(CTAB,a cationic surfactant) and antibiotic drug(cefixime trihydrate(CMT)) in water and also in occurrence of inorganic salts(NaCl,Na2 SO4 and Na3 PO4) over the temperature range of 303.15-323.15 K with an interval of 5 K.In all cases,two critical micelle concentrations(c^*) were achieved for the CMT-surfactant system.Addition of CMT drug to CTAB solution decreases the values of c^* which indicates the interaction between CMT and CTAB.Both values of c^* for CMT-CTAB mixture in the presence of salts are lower in magnitude compared to the aqueous medium which indicates that micellization of the CMT-CTAB mixed system is favorable in salt solution.The values of △Gm^0 were obtained to be negative indicating the spontaneity of the micellization process and the extent of spontaneity further increases by means of rising temperature.The obtained outcomes from the ΔHm^0 and ΔSm^0 values disclose that the interactions between CMT and CTAB are mostly electrostatic along with hydrophobic in nature.The thermodynamic parameters of transfer and enthalpy-entropy compensation phenomenon were also determined and discussed in detail.展开更多
Aluminium trihydrate(ATH) is being extensively added to polypropylene(PP) to make a fire retardant composite. Blends of PP/ATH composite are more fire resistant as compared to pure PP. Percentage proportion of both th...Aluminium trihydrate(ATH) is being extensively added to polypropylene(PP) to make a fire retardant composite. Blends of PP/ATH composite are more fire resistant as compared to pure PP. Percentage proportion of both the constituents in the final composite depends upon the application. Improvement in the fire retardant properties of such composites have been studied and published in literature but effects on mechanical strength have not been addressed. The effect of concentration of ATH on the strength of PP/ATH composite was presented. The tensile, flexural and fracture properties were studied and discussed. Experimental tests, ASTM analytical formulae and finite element approach were used. It has been found that increase in ATH has an inverse effect on the mechanical strength.展开更多
A CO2/NaAlO2/H2O absorption-reaction system was adopted to prepare nano aluminum trihydrate (ATH) particles for cables use in a rotating packed-bed (RPB) reactor (Phase I). The Taguchi experimental design was used to ...A CO2/NaAlO2/H2O absorption-reaction system was adopted to prepare nano aluminum trihydrate (ATH) particles for cables use in a rotating packed-bed (RPB) reactor (Phase I). The Taguchi experimental design was used to give an orthogonal array, L9(34). The parameters were the speed of rotation (A), gas-liquid flow rate ratio (B), aging temperature (C) and aging time (D), each having three levels. According to the signal/noise (S/N) ratio analysis, optimum condition for BET area (Sw) was found to be A3B3C1D1, while the parameter significance was DABC. Empirical formula for Sw was also obtained and discussed. Subsequently, the optimum size (10.7 nm) of ATH powders was used to blend with the matrix including plastics and additives (Phase II) for characterization further. The examination of composite materials showed that the limiting oxygen index (LOI) was higher than 28, indicating an excellent fire-retarding property. The results also showed that the LOI for nano ATH is higher than that bought from the market, while the fire-retarding grade examination (UL-94 test) for both ATHs was found to be of a V-0 grade. In addition, the mechanical properties for nano ATH were measured prior to using the ATH from the market.展开更多
Phase change materials(PCMs)are a kind of highly efficient thermal storage materials which have a bright application prospect in many fields such as energy conservation in buildings,waste heat recovery,battery thermal...Phase change materials(PCMs)are a kind of highly efficient thermal storage materials which have a bright application prospect in many fields such as energy conservation in buildings,waste heat recovery,battery thermal management and so on.Especially inorganic hydrated salt PCMs have received increasing attention from researchers due to their advantages of being inexpensive and non-flammable.However,inorganic hydrated salt PCMs are still limited by the aspects of inappropriate phase change temperature,liquid phase leakage,large supercooling and severe phase separation in the application process.In this work,sodium acetate trihydrate was selected as the basic inorganic PCM,and a novel shape-stabilized composite phase change material(CPCM)with good thermal properties was prepared by adding various functional additives.At first,the sodium acetate trihydrate-acetamide binary mixture was prepared and the melting point was adjusted using acetamide.Then the binary mixture was incorporated into expanded graphite to synthesize a novel shape-stabilized CPCM.The thermophysical properties of the resultant shape-stabilized CPCM were systematically investigated.The microscopic morphology and chemical structure of the obtained shape-stabilized CPCM were characterized and analyzed.The experiment results pointed out that acetamide could effectively lower the melting point of sodium acetate trihydrate.The obtained shape-stabilized CPCM modified with additional 18%(mass fraction)acetamide and 12%(mass fraction)expanded graphite exhibited good shape stability and thermophysical characteristics:a low supercooling degree of 1.75℃and an appropriate melting temperature of 40.77℃were obtained;the latent heat of 151.64 kJ/kg and thermal conductivity of 1.411 W/(m·K)were also satisfactory.Moreover,after 50accelerated melting-freezing cycles,the obtained shape-stabilized CPCM represented good thermal reliability.展开更多
Energy storage devices are the hub of a multi-energy complementary distributed energy system.Hydrated salts are the most suitable phase change material for energy storage devices,but subcooling is the main obstacle to...Energy storage devices are the hub of a multi-energy complementary distributed energy system.Hydrated salts are the most suitable phase change material for energy storage devices,but subcooling is the main obstacle to their application.Nucleation requires a driving force so the use of nucleating agents alone does not reduce subcooling to a very low level.To address this issue,this paper first screened nucleating agents and then further reduced the subcooling of sodium acetate trihydrate in conjunction with stirring or direct current.The effects of rotor mass,rotational speed,direct current voltage,and electrode material on nucleation were analyzed.Finally,the stability of the composite phase change material in the presence of simultaneous stirring and energization was analyzed.The results showed that the addition of 1.5%in weight of disodium hydrogen phosphate dodecahydrate to sodium acetate trihydrate can reduce the subcooling to about 2.3℃.Continued addition of stirring or electricity can reduce the subcooling of sodium acetate trihydrate to within 0.5℃ or even eliminate it.The higher the momentum of the stirring,the better the improvement in subcooling,phase separation,and thermal conductivity.The higher the direct current voltage,the better the nucleation effect,but the electrode life will be lower.The silver electrode has the best nucleation effect.No new material was produced in the solution after 100 cycles in the presence of both stirring and direct current.The melting point of the phase change material was increased by 0.2℃ and the latent heat value decreased by 1.8%,still with good stability.The trace of deionized water should be added to the phase change material in subsequent studies to compensate for the consumption ofwaterby theanodicelution.展开更多
For the first time,one of the antibiotic nanoparticles such as a classical form of ampicillin trihydrate compound was studied.The electrochemical behavior of ampicillin nanoparticles was investigated in blood medium u...For the first time,one of the antibiotic nanoparticles such as a classical form of ampicillin trihydrate compound was studied.The electrochemical behavior of ampicillin nanoparticles was investigated in blood medium using cyclic voltammetric technique by glassy carbon electrode.The results showed that the oxidation-reduction current peaks of ampicillin nanoparticles in blood medium were different from that of microparticles.The nanoparticles acted as anti-oxidative antibiotic by making the oxidation current peak at 1 V disappear,while the oxidation peak of microparticles still appeared in blood medium;hence,ampicillin at microform acted as oxidative reagent in blood medium.A good reliability and stability of glassy carbon electrode in blood medium was found with low values of RSD for oxidation-reduction current peaks at±0.52%and±0.038%respectively.Scanning electron microscopy for the characterization of ampicillin trihydrate nanoparticles was studied.展开更多
Effect of lithium ion in sodium aluminate solution on precipitation rate,lithium content,morphology,and crystallization of alumina trihydrate(ATH) was investigated. Results showed that increasing lithium ion concentra...Effect of lithium ion in sodium aluminate solution on precipitation rate,lithium content,morphology,and crystallization of alumina trihydrate(ATH) was investigated. Results showed that increasing lithium ion concentration in solution improved the precipitation rate and lithium content in ATH,whereas reduced the mass fraction of lithium precipitation from solution. Lithium ion in solution generated the fine ATH, and thereafter significantly increased the total particle number due to the preferential nucleation.Elevating temperature or reducing lithium ion concentration decreased lithium content in ATH and reduced the fine particle amount.Moreover, lithium ion in the solution changed the morphology of ATH by improving the growth of the(110) and(200) planes of gibbsite.A large amount of fine bar-or flake-shaped ATH attached on the coarse particles also benefited the secondary nucleation and led to the poor strength of alumina.All results will further contribute to improving the quality of alumina.展开更多
Cloud point （CP） determinations of 4-（1,1,3,3-tetramethylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium tri...Cloud point （CP） determinations of 4-（1,1,3,3-tetramethylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium trihydrate （CFT））/（CFT ＋ different inorganic salts） and discussed thoroughly. Nonionic surfactants are employed exten- sively in different formulations. In aqueous solution, the values of CP of TX-100 are obtained to increase by means of enhancing of their concentration in the solution. The CP values of TX-100 solutions were found to de- crease in the presence of drug and their values decrease more with rising concentrations of the drug. The values of CP of CFT and TX-100 mixtures were found to further decrease in the attendance of inorganic salts in compar- ison to their absence. The effect of different sodium salts in decreasing CP values of TX-100 was achieved in the following order： NaCO3 〉 Na2SO4 〉 NaCl. However, in the case of potassium and ammonium salts, the decreasing order obtained is K2SO4 〉 KCO3 〉 KCI and （NH4）2SO4 〉 Na2CO3 〉 NH4Cl respectively. Various thermodynamic pa- rameters for example standard free energy （△G c）, standard enthalpy （△H c） as well as standard entropy （△S c） changes of phase separation were also evaluated and discussed in detail on the basis of their behavior.展开更多
Objective:To investigate the in vitro effects of the antihacterial drugs,mcropenem trihydrate.piperacillin sodium,and cefoperazone sodium,on the activity of human serum paraoxonase mPOND.Methods:hPQN1 was purified fro...Objective:To investigate the in vitro effects of the antihacterial drugs,mcropenem trihydrate.piperacillin sodium,and cefoperazone sodium,on the activity of human serum paraoxonase mPOND.Methods:hPQN1 was purified from human serum using simple chromatographic methods.including DEAE-Sephadex anion exchange and Sephadex G-200 gel filtration chromatography.Results:The three antihacterial drugs decreased in vitro hPON1 activity.Inhibition mechanisms meropcnem trihydrate was noncompetitive while piperacillin sodium and cefoperazone sodium were competitive.Conclusions:Our results showed that antihacterial drugs significantly inhibit hPON1 activity,both in vitro,with rank order meropenem trihydrate piperacillin sodium cefoperazone sodium in vitro.展开更多
文摘Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.
基金Project(51274242)supported by the National Natural Science Foundation of China
文摘High soda content in fine alumina trihydrate（ATH） limits its application and increases the soda consumption. The variation of soda content in the fine ATH by seeded precipitation was determined by detection of electric conductivity of solution, soda content in ATH, measurement of particle size distribution and microscopic analysis. The results show that high concentration of sodium aluminate solution, ground circulative seed, low temperature or fast initial precipitation rate increases the soda content in ATH. Soda mainly exists in lattice soda and less soda in desilication product （DSP） exists in the fine ATH precipitated from sodium aluminate solution with concentration of Al2O3 （ρAl2O3） more than 160 g/L and mass ratio of alumina to silica （μSiO2） of 400, and lattice soda decreases with increasing initial precipitation temperature, aging seed, and low precipitation rate and precipitation time. Results also imply that -＋ 4）Na Al（OH ion-pair influences lattice soda content in ATH on the basis of electric conductivity variation.
基金financially supported by the National Natural Science Foundation of China (No. 51274242)
文摘The surface properties of superfine alumina trihydrate （ATH） after surface modification were studied by measuring the contact angle, active ratio, oil adsorption, total organic carbon, adsorption ratio, and Fourier transform infrared （FTIR） spectrum. The contact angle increased initially and then slowly decreased with an increase of the amount of stearic acid. However, the surface flee energy decreased ini- tially and then increased. Surface modification with stearic acid or sodium stearate can benefit from elevating temperature. The base surface tension component and the free energy of Lewis acid-base both declined sharply following the surface modification. Excess stearic acid was physically adsorbed in the form of multilayer adsorption, and an interaction between oxygen on the ATH surface and hydroxyl in stearic acid was subsequently determined. Our results further indicated that the contact angle and adsorption ratio can be used as control indicators for surface modification compared with active ratio, oil adsorption and total organic carbon.
基金Supported by Tianjin Municipal Natural Science Foundation(16JCYBJC19500)China Ministry of Science and Major National Scientific Instrument Development Project(2016YFF0102503)
文摘The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent composition and temperature on solubility of meropenem trihydrate were discussed.To extend the applicability of the solubility data,experimental solubility data in two kinds of binary solvent mixtures were correlated by the Apelblat equation and NIBS/Redlich–Kister model.It was found that the two models could satisfactorily correlate the experimental data and the Apelblat equation could give better correlation results.
基金Jahangirnagar University, Savar, Dhaka, Bangladesh for providing financial support to carry out the research work
文摘Herein,conductivity measurements have been carried out to explore the interaction between cetyltrimethylammonium bromide(CTAB,a cationic surfactant) and antibiotic drug(cefixime trihydrate(CMT)) in water and also in occurrence of inorganic salts(NaCl,Na2 SO4 and Na3 PO4) over the temperature range of 303.15-323.15 K with an interval of 5 K.In all cases,two critical micelle concentrations(c^*) were achieved for the CMT-surfactant system.Addition of CMT drug to CTAB solution decreases the values of c^* which indicates the interaction between CMT and CTAB.Both values of c^* for CMT-CTAB mixture in the presence of salts are lower in magnitude compared to the aqueous medium which indicates that micellization of the CMT-CTAB mixed system is favorable in salt solution.The values of △Gm^0 were obtained to be negative indicating the spontaneity of the micellization process and the extent of spontaneity further increases by means of rising temperature.The obtained outcomes from the ΔHm^0 and ΔSm^0 values disclose that the interactions between CMT and CTAB are mostly electrostatic along with hydrophobic in nature.The thermodynamic parameters of transfer and enthalpy-entropy compensation phenomenon were also determined and discussed in detail.
基金Projects(2012-00094552012-0008302) supported by the National Research Foundation of Korea(NRF) Grant Funded by the Korea Government(MEST)
文摘Aluminium trihydrate(ATH) is being extensively added to polypropylene(PP) to make a fire retardant composite. Blends of PP/ATH composite are more fire resistant as compared to pure PP. Percentage proportion of both the constituents in the final composite depends upon the application. Improvement in the fire retardant properties of such composites have been studied and published in literature but effects on mechanical strength have not been addressed. The effect of concentration of ATH on the strength of PP/ATH composite was presented. The tensile, flexural and fracture properties were studied and discussed. Experimental tests, ASTM analytical formulae and finite element approach were used. It has been found that increase in ATH has an inverse effect on the mechanical strength.
文摘A CO2/NaAlO2/H2O absorption-reaction system was adopted to prepare nano aluminum trihydrate (ATH) particles for cables use in a rotating packed-bed (RPB) reactor (Phase I). The Taguchi experimental design was used to give an orthogonal array, L9(34). The parameters were the speed of rotation (A), gas-liquid flow rate ratio (B), aging temperature (C) and aging time (D), each having three levels. According to the signal/noise (S/N) ratio analysis, optimum condition for BET area (Sw) was found to be A3B3C1D1, while the parameter significance was DABC. Empirical formula for Sw was also obtained and discussed. Subsequently, the optimum size (10.7 nm) of ATH powders was used to blend with the matrix including plastics and additives (Phase II) for characterization further. The examination of composite materials showed that the limiting oxygen index (LOI) was higher than 28, indicating an excellent fire-retarding property. The results also showed that the LOI for nano ATH is higher than that bought from the market, while the fire-retarding grade examination (UL-94 test) for both ATHs was found to be of a V-0 grade. In addition, the mechanical properties for nano ATH were measured prior to using the ATH from the market.
基金financially supported by the National Natural Science Foundation of China(5220608752130607)+7 种基金the Key R&D Program of Gansu Province(23YFGA006623YFGA0035)the Industrial Support Plan Project of Gansu Provincial Education Department(2022CYZC-212021CYZC-27)the Doctoral Research Funds of Lanzhou University of Technology(061907)the Incubation Program of Excellent Doctoral Dissertation-Lanzhou University of Technologythe Red Willow Excellent Youth Project of Lanzhou University of Technologythe Open Fund of Key Laboratory of Multi-supply System with Solar Energy and Biomass of Gansu Province。
文摘Phase change materials(PCMs)are a kind of highly efficient thermal storage materials which have a bright application prospect in many fields such as energy conservation in buildings,waste heat recovery,battery thermal management and so on.Especially inorganic hydrated salt PCMs have received increasing attention from researchers due to their advantages of being inexpensive and non-flammable.However,inorganic hydrated salt PCMs are still limited by the aspects of inappropriate phase change temperature,liquid phase leakage,large supercooling and severe phase separation in the application process.In this work,sodium acetate trihydrate was selected as the basic inorganic PCM,and a novel shape-stabilized composite phase change material(CPCM)with good thermal properties was prepared by adding various functional additives.At first,the sodium acetate trihydrate-acetamide binary mixture was prepared and the melting point was adjusted using acetamide.Then the binary mixture was incorporated into expanded graphite to synthesize a novel shape-stabilized CPCM.The thermophysical properties of the resultant shape-stabilized CPCM were systematically investigated.The microscopic morphology and chemical structure of the obtained shape-stabilized CPCM were characterized and analyzed.The experiment results pointed out that acetamide could effectively lower the melting point of sodium acetate trihydrate.The obtained shape-stabilized CPCM modified with additional 18%(mass fraction)acetamide and 12%(mass fraction)expanded graphite exhibited good shape stability and thermophysical characteristics:a low supercooling degree of 1.75℃and an appropriate melting temperature of 40.77℃were obtained;the latent heat of 151.64 kJ/kg and thermal conductivity of 1.411 W/(m·K)were also satisfactory.Moreover,after 50accelerated melting-freezing cycles,the obtained shape-stabilized CPCM represented good thermal reliability.
基金the Shandong Province Natural Science Foundation (NO.ZR2020ME190)Cyrus Chung Ying Tang Foundation for the financial support
文摘Energy storage devices are the hub of a multi-energy complementary distributed energy system.Hydrated salts are the most suitable phase change material for energy storage devices,but subcooling is the main obstacle to their application.Nucleation requires a driving force so the use of nucleating agents alone does not reduce subcooling to a very low level.To address this issue,this paper first screened nucleating agents and then further reduced the subcooling of sodium acetate trihydrate in conjunction with stirring or direct current.The effects of rotor mass,rotational speed,direct current voltage,and electrode material on nucleation were analyzed.Finally,the stability of the composite phase change material in the presence of simultaneous stirring and energization was analyzed.The results showed that the addition of 1.5%in weight of disodium hydrogen phosphate dodecahydrate to sodium acetate trihydrate can reduce the subcooling to about 2.3℃.Continued addition of stirring or electricity can reduce the subcooling of sodium acetate trihydrate to within 0.5℃ or even eliminate it.The higher the momentum of the stirring,the better the improvement in subcooling,phase separation,and thermal conductivity.The higher the direct current voltage,the better the nucleation effect,but the electrode life will be lower.The silver electrode has the best nucleation effect.No new material was produced in the solution after 100 cycles in the presence of both stirring and direct current.The melting point of the phase change material was increased by 0.2℃ and the latent heat value decreased by 1.8%,still with good stability.The trace of deionized water should be added to the phase change material in subsequent studies to compensate for the consumption ofwaterby theanodicelution.
文摘For the first time,one of the antibiotic nanoparticles such as a classical form of ampicillin trihydrate compound was studied.The electrochemical behavior of ampicillin nanoparticles was investigated in blood medium using cyclic voltammetric technique by glassy carbon electrode.The results showed that the oxidation-reduction current peaks of ampicillin nanoparticles in blood medium were different from that of microparticles.The nanoparticles acted as anti-oxidative antibiotic by making the oxidation current peak at 1 V disappear,while the oxidation peak of microparticles still appeared in blood medium;hence,ampicillin at microform acted as oxidative reagent in blood medium.A good reliability and stability of glassy carbon electrode in blood medium was found with low values of RSD for oxidation-reduction current peaks at±0.52%and±0.038%respectively.Scanning electron microscopy for the characterization of ampicillin trihydrate nanoparticles was studied.
基金Project(2015BAB04B01)supported by the National Key Technology Research&Development Program of ChinaProject(CSUZC201811)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘Effect of lithium ion in sodium aluminate solution on precipitation rate,lithium content,morphology,and crystallization of alumina trihydrate(ATH) was investigated. Results showed that increasing lithium ion concentration in solution improved the precipitation rate and lithium content in ATH,whereas reduced the mass fraction of lithium precipitation from solution. Lithium ion in solution generated the fine ATH, and thereafter significantly increased the total particle number due to the preferential nucleation.Elevating temperature or reducing lithium ion concentration decreased lithium content in ATH and reduced the fine particle amount.Moreover, lithium ion in the solution changed the morphology of ATH by improving the growth of the(110) and(200) planes of gibbsite.A large amount of fine bar-or flake-shaped ATH attached on the coarse particles also benefited the secondary nucleation and led to the poor strength of alumina.All results will further contribute to improving the quality of alumina.
基金Jahangirnagar University,Savar,Dhaka,Bangladesh for providing financial support to carry out the research work
文摘Cloud point （CP） determinations of 4-（1,1,3,3-tetramethylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium trihydrate （CFT））/（CFT ＋ different inorganic salts） and discussed thoroughly. Nonionic surfactants are employed exten- sively in different formulations. In aqueous solution, the values of CP of TX-100 are obtained to increase by means of enhancing of their concentration in the solution. The CP values of TX-100 solutions were found to de- crease in the presence of drug and their values decrease more with rising concentrations of the drug. The values of CP of CFT and TX-100 mixtures were found to further decrease in the attendance of inorganic salts in compar- ison to their absence. The effect of different sodium salts in decreasing CP values of TX-100 was achieved in the following order： NaCO3 〉 Na2SO4 〉 NaCl. However, in the case of potassium and ammonium salts, the decreasing order obtained is K2SO4 〉 KCO3 〉 KCI and （NH4）2SO4 〉 Na2CO3 〉 NH4Cl respectively. Various thermodynamic pa- rameters for example standard free energy （△G c）, standard enthalpy （△H c） as well as standard entropy （△S c） changes of phase separation were also evaluated and discussed in detail on the basis of their behavior.
基金Supported by Atatrk University Scientific Research Project Fund(BAP-2009/81)
文摘Objective:To investigate the in vitro effects of the antihacterial drugs,mcropenem trihydrate.piperacillin sodium,and cefoperazone sodium,on the activity of human serum paraoxonase mPOND.Methods:hPQN1 was purified from human serum using simple chromatographic methods.including DEAE-Sephadex anion exchange and Sephadex G-200 gel filtration chromatography.Results:The three antihacterial drugs decreased in vitro hPON1 activity.Inhibition mechanisms meropcnem trihydrate was noncompetitive while piperacillin sodium and cefoperazone sodium were competitive.Conclusions:Our results showed that antihacterial drugs significantly inhibit hPON1 activity,both in vitro,with rank order meropenem trihydrate piperacillin sodium cefoperazone sodium in vitro.
