Adsorption kinetics in multi-component systems has been a subject of intensive research because it is of both theoretical and practical importance. In this paper, raw date palm seeds （RDPS） were investigated to asse...Adsorption kinetics in multi-component systems has been a subject of intensive research because it is of both theoretical and practical importance. In this paper, raw date palm seeds （RDPS） were investigated to assess the possible use of this raw material as an effective adsorbent for the removal of sulfate from aqueous solution. The influence of various parameters such as sulfate initial concentration, pH, adsorbent dose and stirring time has been studied for the adsorption of sulfate in batch mode. Effects of foreign anions on the adsorption of sulfate onto RDPS have been also investigated. The pseudo-second-order, Elovich and intraparticle diffusion kinetic models have been developed to predict the rate constants of adsorption and equilibrium capacities. The maximum adsorption capacity of sulfate （qe ≈3.2 mg/g） onto RDPS was reached for the initial sulfate concentration = 100 mg/L, pH - 3.5, adsorbent dose = 10 g/L and for a stirring intensity = 200 rpm at 25 ± 2 ℃. The results showed that the adsorption of sulfate onto this raw materials followed pseudo-second-order rate kinetic predicting a chemisorption process.展开更多
A sensitive and specific high performance liquid chromatography （HPLC） method was developed and validated for the simultaneous determination of metformin hydrochloride （HCI） in human plasma. The HPLC method consis...A sensitive and specific high performance liquid chromatography （HPLC） method was developed and validated for the simultaneous determination of metformin hydrochloride （HCI） in human plasma. The HPLC method consists of isocratic eluation with a mixture of 60% buffer （10 mM sodium dihyrogenphosphate-10 mM sodium dodecyl sulphate） and 40% acetonitrile with final pH 7.0 with flow rate of 1.0 mL/min on a Kromasil~ Akzo Nobel RP-18 （4.6 mm ID ~ 250 mm, 5 ~tm） column at an ambient temperature. Photo diode array detection was performed in program mode at 234 rim. The analyte and diazepam as internal standard （IS） were extracted from plasma using 10% trichloroacetic acid. The assay was linear over the therapeutic concentration range of 20-2,500 ng/mL for metformin HCI with correlation coefficient of r = 0.9999. Limit of quantitation was 20 ng/mL. The results obtained for intraJinter day accuracy and precision complied very well with the generally accepted criteria for bio-analytical assay. The method was applied to bioequivalence （BE） study of metformin HCI in healthy Indonesian volunteers after treatment with 750 mg XR metformin HCI. This BE study shows that the two formulations are equivalent so that they were therapeutically interchangeable for each other.展开更多
Glow discharge electrolysis provides an alternative method for the removal of arsenite from water. Glow discharge electrolysis of aqueous solution containing arsenite is studied under altemating current altemating cur...Glow discharge electrolysis provides an alternative method for the removal of arsenite from water. Glow discharge electrolysis of aqueous solution containing arsenite is studied under altemating current altemating current （50 Hz） discharge. It is found that arsenite [As（III）] get converted to arsenate [As（V）]. The yield is studied with various parameters such as discharge current, duration of discharge and pH （2-10）. The results are interpreted on the basis of interaction of the OH and eaq （produced consequent to the interaction of H2O＋ and e with water at the surface of the solution） with arsenite [As（III）] through the intermediate oxidation state, namely [As（IV）].展开更多
Wound healing has invariably been a fundamental health concern,demanding manpower and materials and causing financial burdens.In this research,inspired by the hemostatic function of platelets,we proposed a novel bioni...Wound healing has invariably been a fundamental health concern,demanding manpower and materials and causing financial burdens.In this research,inspired by the hemostatic function of platelets,we proposed a novel bionic hydrogel by covalent amidation crosslinking natural platelet and alginate for wound healing.With the natural functional groups,the platelet-derived hydrogel exhibited outstanding biocompatibility and blood compatibility.By changing the addition ratio of platelets to alginates,the mechanical properties of the achieved hydrogel were variable to cater to different wound environments.Furthermore,silver nanoparticles could be loaded into the void space of the hydrogel which endowed the composites with superior anti-infective properties.We have demonstrated that the bio-inspired platelet hydrogel could promote hemostasis of acute tissue damage,prevent bacterial proliferation,and promote angiogenesis,collagen deposition,and granulation tissue formation in wound healing.These features signify the potential values of the bio-inspired platelet hydrogel in clinical applications.展开更多
Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite diff...Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite different,which may directly affect the therapeutic effect of the drug.To this end,11 different production producers of berberine hydrochloride tablets were collected according to the pharmacopeia berberine hydrochloride dissolution method(basket method).In addition the dissolution process was carried out in four elution media with different pH,and the difference was similar(f2).Factors were calculated to evaluate in vitro dissolution requirements,and in vitro dissolution of different manufacturers of berberine hydrochloride tablets was determined by high performance liquid chromatography(HPLC).The method was verified by linearity,precision,stability and robustness.Based on the f2 value,there was a significant difference in the dissolution behavior of the formulations of most berberine hydrochloride tablet brands.This research provided the basis for further in-depth research in the later period.Although the drug specifications(0.1 g)were the same,the dissolution curve was different.This phenomenon may be attributed to the fact that the excipients and crystal form of the tablets affected the release and dissolution of the tablets in vitro.展开更多
Because laboratory tests are expensive and time-consuming and may not be available to farmers, soil nitrate quick tests are required for optimal nitrogen management strategies in China to increase nitrogen use efficie...Because laboratory tests are expensive and time-consuming and may not be available to farmers, soil nitrate quick tests are required for optimal nitrogen management strategies in China to increase nitrogen use efficiency and to reduce nitrogen losses. A total of 328 soil samples were collected at different soil depths from 225 sites in China, which covered a wide range of climatic and geographic regions, soil types, croplands and soil textures, to evaluate the suitability of a quick reflectometer test method for analysing soil NO3-N in a wide range of soil NO3 concentrations, soil types and cropping systems in China, mainly by comparison of soil NO3-N assessed by a quick-test method （a reflectometer） and a standard laboratory method, i.e., high-performance liquid chromatography （HPLC）. The reflectometer showed excellent agreement with the laboratory HPLC method with regard to soil nitrate contents for all analysed soil samples. The linear regression had slopes of 1 ± 0.08 and intercepts of ± 1.38 mg NO（-,3）-N L^（-1） among different soil types and croplands. Compared with the 1：1 lines, the regression analysis for each soil type showed statistically significant but small differences in slope; the relative difference between the values measured using the two analytical systems varied from -8% to 6%, and there were no differences in intercept except for paddy soil. The reflectometer showed adequate, statistically significant precision in determining soil nitrate contents, and it could therefore be directly used instead of the laboratory methods for soil NO（-,3）-N measurement in China.展开更多
Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated ...Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.展开更多
文摘Adsorption kinetics in multi-component systems has been a subject of intensive research because it is of both theoretical and practical importance. In this paper, raw date palm seeds （RDPS） were investigated to assess the possible use of this raw material as an effective adsorbent for the removal of sulfate from aqueous solution. The influence of various parameters such as sulfate initial concentration, pH, adsorbent dose and stirring time has been studied for the adsorption of sulfate in batch mode. Effects of foreign anions on the adsorption of sulfate onto RDPS have been also investigated. The pseudo-second-order, Elovich and intraparticle diffusion kinetic models have been developed to predict the rate constants of adsorption and equilibrium capacities. The maximum adsorption capacity of sulfate （qe ≈3.2 mg/g） onto RDPS was reached for the initial sulfate concentration = 100 mg/L, pH - 3.5, adsorbent dose = 10 g/L and for a stirring intensity = 200 rpm at 25 ± 2 ℃. The results showed that the adsorption of sulfate onto this raw materials followed pseudo-second-order rate kinetic predicting a chemisorption process.
文摘A sensitive and specific high performance liquid chromatography （HPLC） method was developed and validated for the simultaneous determination of metformin hydrochloride （HCI） in human plasma. The HPLC method consists of isocratic eluation with a mixture of 60% buffer （10 mM sodium dihyrogenphosphate-10 mM sodium dodecyl sulphate） and 40% acetonitrile with final pH 7.0 with flow rate of 1.0 mL/min on a Kromasil~ Akzo Nobel RP-18 （4.6 mm ID ~ 250 mm, 5 ~tm） column at an ambient temperature. Photo diode array detection was performed in program mode at 234 rim. The analyte and diazepam as internal standard （IS） were extracted from plasma using 10% trichloroacetic acid. The assay was linear over the therapeutic concentration range of 20-2,500 ng/mL for metformin HCI with correlation coefficient of r = 0.9999. Limit of quantitation was 20 ng/mL. The results obtained for intraJinter day accuracy and precision complied very well with the generally accepted criteria for bio-analytical assay. The method was applied to bioequivalence （BE） study of metformin HCI in healthy Indonesian volunteers after treatment with 750 mg XR metformin HCI. This BE study shows that the two formulations are equivalent so that they were therapeutically interchangeable for each other.
文摘Glow discharge electrolysis provides an alternative method for the removal of arsenite from water. Glow discharge electrolysis of aqueous solution containing arsenite is studied under altemating current altemating current （50 Hz） discharge. It is found that arsenite [As（III）] get converted to arsenate [As（V）]. The yield is studied with various parameters such as discharge current, duration of discharge and pH （2-10）. The results are interpreted on the basis of interaction of the OH and eaq （produced consequent to the interaction of H2O＋ and e with water at the surface of the solution） with arsenite [As（III）] through the intermediate oxidation state, namely [As（IV）].
基金supported by the National Key Research and Development Program of China(2020YFA0908200)the National Natural Science Foundation of China(52073060 and 22002061)+1 种基金the Natural Science Foundation of Jiangsu(BK20200551)the Shenzhen Fundamental Research Program(JCYJ20190813152616459 and JCYJ20210324133214038)。
文摘Wound healing has invariably been a fundamental health concern,demanding manpower and materials and causing financial burdens.In this research,inspired by the hemostatic function of platelets,we proposed a novel bionic hydrogel by covalent amidation crosslinking natural platelet and alginate for wound healing.With the natural functional groups,the platelet-derived hydrogel exhibited outstanding biocompatibility and blood compatibility.By changing the addition ratio of platelets to alginates,the mechanical properties of the achieved hydrogel were variable to cater to different wound environments.Furthermore,silver nanoparticles could be loaded into the void space of the hydrogel which endowed the composites with superior anti-infective properties.We have demonstrated that the bio-inspired platelet hydrogel could promote hemostasis of acute tissue damage,prevent bacterial proliferation,and promote angiogenesis,collagen deposition,and granulation tissue formation in wound healing.These features signify the potential values of the bio-inspired platelet hydrogel in clinical applications.
基金National Institutes for Food and Drug Control(Grant No.017ZX09101001).
文摘Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite different,which may directly affect the therapeutic effect of the drug.To this end,11 different production producers of berberine hydrochloride tablets were collected according to the pharmacopeia berberine hydrochloride dissolution method(basket method).In addition the dissolution process was carried out in four elution media with different pH,and the difference was similar(f2).Factors were calculated to evaluate in vitro dissolution requirements,and in vitro dissolution of different manufacturers of berberine hydrochloride tablets was determined by high performance liquid chromatography(HPLC).The method was verified by linearity,precision,stability and robustness.Based on the f2 value,there was a significant difference in the dissolution behavior of the formulations of most berberine hydrochloride tablet brands.This research provided the basis for further in-depth research in the later period.Although the drug specifications(0.1 g)were the same,the dissolution curve was different.This phenomenon may be attributed to the fact that the excipients and crystal form of the tablets affected the release and dissolution of the tablets in vitro.
基金the German Federal Ministry of Education and Research (BMBF) (No.00330800A)
文摘Because laboratory tests are expensive and time-consuming and may not be available to farmers, soil nitrate quick tests are required for optimal nitrogen management strategies in China to increase nitrogen use efficiency and to reduce nitrogen losses. A total of 328 soil samples were collected at different soil depths from 225 sites in China, which covered a wide range of climatic and geographic regions, soil types, croplands and soil textures, to evaluate the suitability of a quick reflectometer test method for analysing soil NO3-N in a wide range of soil NO3 concentrations, soil types and cropping systems in China, mainly by comparison of soil NO3-N assessed by a quick-test method （a reflectometer） and a standard laboratory method, i.e., high-performance liquid chromatography （HPLC）. The reflectometer showed excellent agreement with the laboratory HPLC method with regard to soil nitrate contents for all analysed soil samples. The linear regression had slopes of 1 ± 0.08 and intercepts of ± 1.38 mg NO（-,3）-N L^（-1） among different soil types and croplands. Compared with the 1：1 lines, the regression analysis for each soil type showed statistically significant but small differences in slope; the relative difference between the values measured using the two analytical systems varied from -8% to 6%, and there were no differences in intercept except for paddy soil. The reflectometer showed adequate, statistically significant precision in determining soil nitrate contents, and it could therefore be directly used instead of the laboratory methods for soil NO（-,3）-N measurement in China.
基金supported by the Major Scientific Equipment Development Project of China(2012YQ030111)the Beijing Natural Science Foundation(8132032)
文摘Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.
