The knowledge of the pathogenesis of type 1 diabetes mellitus(T1DM)continues to rapidly evolve.The natural course of the disease can be described in four clinical stages based on the autoimmune markers and glycemic st...The knowledge of the pathogenesis of type 1 diabetes mellitus(T1DM)continues to rapidly evolve.The natural course of the disease can be described in four clinical stages based on the autoimmune markers and glycemic status.Not all individuals of T1DM progress in that specific sequence.We hereby present a case of T1DM with a classical third phase(honeymoon phase)and discuss the intri-cacies of this interesting phase along with a possible future promise of“cure”with the use of immunotherapies.We now know that the course of T1DM may not be in only one direction towards further progression;rather the disease may have a waxing and waning course with even reversal of type 1 diabetes concept being discussed.The third phase popularly called the“honeymoon phase”,is of special interest as this phase is complex in its pathogenesis.The honeymoon phase of T1DM seems to provide the best window of opportunity for using targeted therapies using various immunomodulatory agents leading to the possibility of achieving the elusive“diabetes reversal”in T1DM.Identifying this phase is therefore the key,with a lot of varying criteria having been proposed.展开更多
Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step s...Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.展开更多
The thermodynamic instability of zinc anodes in aqueous electrolytes leads to issues such as corrosion,hydrogen evolution reactions(HER), and dendrite growth, severely hindering the practical application of zinc-based...The thermodynamic instability of zinc anodes in aqueous electrolytes leads to issues such as corrosion,hydrogen evolution reactions(HER), and dendrite growth, severely hindering the practical application of zinc-based aqueous energy storage devices. To address these challenges, this work proposes a dualfunction zinc anode protective layer, composed of Zn-Al-In layered double oxides(ILDO) by rationally designing Zn-Al layered double hydroxides(Zn-Al LDHs) for the first time. Differing from previous works on the LDHs coatings, firstly, the ILDO layer accelerates zinc-ion desolvation and also captures and anchors SO_(4)^(2-). Secondly, the in-situ formation of the Zn-In alloy phase effectively lowers the nucleation energy barrier, thereby regulating zinc nucleation. Consequently, the zinc anode with the ILDO protective layer demonstrates long-term stability exceeding 1900 h and low voltage hysteresis of 7.5 m V at 0.5 m A cm^(-2) and 0.5 m A h cm^(-2). Additionally, it significantly enhances the rate capability and cycling performance of Zn@ILDO//MnO_(2) full batteries and Zn@ILDO//activated carbon zinc-ion hybrid capacitors.This simple and effective dual-function protective layer strategy offers a promising approach for achieving high-performance zinc-ion batteries.展开更多
Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart di...Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.展开更多
[Objectives] To establish the high performance liquid chromatography( HPLC) determination method for oxysophocarpine and optimize the extraction and purification technology of oxysophocarpine from Sophora alopecuroide...[Objectives] To establish the high performance liquid chromatography( HPLC) determination method for oxysophocarpine and optimize the extraction and purification technology of oxysophocarpine from Sophora alopecuroides by inverse three-phase membrane cycle.[Methods]Based on the single-factor experiment,the effects of aqueous phase and organic phase volume ratio,the concentration of sodium hydroxide,concentration of hydrochloric acid and extraction cycle time on extraction process of oxysophocarpine were investigated using orthogonal design method,to determine the optimal extraction process. [Results]The oxysophocarpine was determined by Shim-pack VP-ODS chromatographic column( 4. 6 mm × 250 mm,5 μm),mobile phase was methanol-0. 2% phosphoric acid aqueous solution( 7∶ 93),gradient elution,flow rate was 1 m L/min,the sample size was 5 μm,column temperature was 30℃,detection wavelength was 221 nm. Aqueous phase and organic phase volume ratio was 1∶ 1,hydrochloric acid concentration was 0. 3 mol/L,sodium hydroxide concentration was 0. 75 mol/L,water pump flow rate was 6 m L/min,60 min cycle time. The extraction rate of oxysophocarpine 98. 21 % within 60 min under the best experimental conditions. Oxysophocarpine has good linearity relationship within the range of 0. 01-0. 7 mg/m L( r^2= 0. 9978,n = 6),the respective average recovery rate was 97. 47%( RSD = 1. 95%). [Conclusions] This extraction process is simple in operation,the organic solvent has low consumption,and can be used for extraction of alkaloid.展开更多
High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, r...High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A isolated from the leaves of Stevia rebaudiana using Reversed-Phase (RP) column. Using RP-HPLC method, the individual retention times for nine naturally occurring ent-kaurane diterpene glycosides of S. rebaudiana reported in JECFA have been determined at four different temperatures: 20℃, 40℃, 60℃, and 79℃. Also, calculated the relative retention times of the eight steviol glycosides steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A against the major steviol glycoside rebaudioside A. HPLC results suggested that temperatures 40℃ and 60℃ would be ideal conditions for better separation of steviol glycosides.展开更多
Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per- formed for full ...Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per- formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor- mance liquid chromatography with diode array detection ((RP)HPLC/DAD) is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo- nization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci- sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre- hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de- monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc- cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.展开更多
A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromato...A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromatography was performed on a Purospher? Star, C18 (5 mm, 250 × 4.6 mm) column using acetonitrile: buffer (0.01 mM) (40:60, v/v, pH adjusted to 3.0), as a mobile phase. The mobile phase was pumped at a flow rate of 1.0 mL·min-1 and UV detection was performed at 240 nm. The method was validated for linearity, accuracy, precision and specificity. The method was applied to study the interaction between amlodipine and H1-receptor antagonists. These interactions were carried out in simulated gastric juice (pH 1), simulated full stomach (pH 4), blood pH (pH 7.4) and simulating GI (pH 9). The interacting drugs were heated at 37℃ with intermit-tent shaking and the samples were withdrawn every thirty minutes for three hours and drug contents were analyzed by RP-HPLC techniques. In most cases the in vitro availability of amlodipine was decreased. It was observed that the change in in vitro availability was pH dependent.展开更多
The research was carried out for establishing a new reverse phase-HPLC stability indicating method for the quantification of Rucaparib. The experiment was determined on Waters HPLC instrument using 996 photo-diode arr...The research was carried out for establishing a new reverse phase-HPLC stability indicating method for the quantification of Rucaparib. The experiment was determined on Waters HPLC instrument using 996 photo-diode array detector. The separation was done by using symmetry C-18 ODS (25 cm × 0.46 cm internal diameter) 5 μm analytical column containing mobile phase of Phosphate buffer (0.02 M) and methanol [65:35% v/v] adjusted pH to 4.8 by adding dilute ortho phosphoric acid. The method was run at 1 ml·min<sup>-1</sup> at 286 nm detection. The drug was eluted at 5.484 min. After developing the method, it was assured for the intended use by validation which was done according to ICH Q2B guidelines. The analytical parameters checked were linearity, accuracy, repeatability, intermediate precision, limit of detection, limit of quantitation, ruggedness and robustness. It was observed that the response of the detector was linear in the range of 6 - 14 μg/ml with correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability indicating assay method was established by using the samples generated by forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative and photolytic degradation and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the analysis of quality of the rucaparib drug.展开更多
Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous ...Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.展开更多
A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation o...A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.展开更多
The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phas...The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.展开更多
AIM:To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography(RP-HPLC),and to evaluate the retinal neuroprotective effect after topical administration with...AIM:To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography(RP-HPLC),and to evaluate the retinal neuroprotective effect after topical administration with moxonidine in a high intraocular pressure(IOP)model.METHODS:The eyes of albino rabbits were administered topically and ipsilaterally with 0.2%moxonidine.A RPHPLC method was employed for the identification and quantification of moxonidine between 2 and 480 min,which presented in the aqueous humor and iris-ciliary body.Flash electroretinography(F-ERG)amplitude and superoxide dismutase(SOD)level were measured between day 1 and day 15 after topical administration with moxonidine in a rabbit model of high IOP.Histological and ultrastructural observation underwent to analyze the changes of retinal morphology,the inner retinal layers(IRL)thickness,and retinal ganglion cell(RGC)counting.RESULTS:Moxonidine was detectable between 2 and 480 min after administration,and the peak concentration developed both in the two tissues at 30 min,0.51μg/m Lin aqueous humor and 1.03μg/g in iris-ciliary body.In comparison to control,F-ERG b-wave amplitude in moxonidine eyes were significantly differences between day 3 and day 15(P<0.01)in the high IOP model;SOD levels were significantly higher at all time-points(P<0.01)with a maximum level of 20.29 U/mgprot at day 15;and RGCs were significantly higher(P<0.05).CONCLUSION:Moxonidine is a viable neuroprotective agent with application to high IOP model.All layers of retina,including RGC layer,retinal nerve fiber layer and INL,are more preserved after moxonidine administration.SOD plays a neuroprotective role in ocular hypertension-mediated RGC death.展开更多
We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein...We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein,we have investigated the use of MT6 in stereo-selective biocatalysis through direct hydrolysis reactions.Notably,the stereo-selectivity of MT6 was also demonstrated to be opposite to that of other common lipases in hydrolysis reactions.Parameters,including temperature,organic co-solvents,pH,ionic strength,catalyst loading,substrate concentration,and reaction time,affecting the enzymatic resolution of racemic 1-phenylethyl acetate were further investigated,with the e.e.of the final(S)-l-Phenylethanol product and the conversion being 97%and 28.5%,respectively,after process optimization.The lengths of side chains of 1-phenylethyl esters greatly affected the stereo-selectivity and conversion during kinetic resolutions.MT6 is a novel marine microbial GDSL lipase exhibiting opposite stereo-selectivities than other common lipases in both trans-esterification reactions and hydrolysis reactions.展开更多
The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency a...The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency and their quality to improve the human health care. Isotretritoin finds its applications in the maintenance of epithelial tissues. Different processes to date such as normal phase HPLC, or gas chromatrography am- ong others are able to separate and quantify isote- troin. However, the extraction is quite complex and in the case of HPLC, the analysis requires long retention times. In such context, an isocratic reversed- phase high-performance liquid chromatography (HP- LC) technique coupled with an UV-vis detector is described here for easy separation and quantification of 13-cis-retinoic (isotretinoin) from soft gelatin capsule formulations. The isotretinoin was extracted from three different commercial drug samples with tetrahydrofuran (THF) solvent by a procedure that can be completed in less than 10 minutes. Subsequent separation and quantification were accomplished in less than 5 minutes under isocratic reversed-phase conditions on a Lichrospher RP18 column and a mobile phase consisting of 0.01% TFA/acetonitrile (15/85, v/v) at a flow rate of 1.0 mL/min. Isotretoin was detected for the three samples via its UV-vis absorbance at 342 nm. The method was validated and the results showed good linearity, precision and accuracy for sensitive and selective quantitative determination of isotretinoin in the different pharmaceutical formulations. We found that the average isotretinoin content in two of the three commercial pro- ducts fell outside the 90-110% United States Pha- rmacopeia specifications. Consequently, the facile extraction and the precise method for the biomole- cule quantification open up tremendous possibilities in improving the quality control of drugs which can exist as different generic brands.展开更多
The research was carried out to establish a new reverse phase-HPLC stability indicating method for quantifying Bimatoprost & Timolol in ophthalmic solution. The experiment of Bimatoprost & Timolol in ophthalmi...The research was carried out to establish a new reverse phase-HPLC stability indicating method for quantifying Bimatoprost & Timolol in ophthalmic solution. The experiment of Bimatoprost & Timolol in ophthalmic solution method development was determined on Waters HPLC instrument using a UV Detector. The separation was done by using L11, Zorbex SB phenyl (4.6 mm × 250 mm internal diameter) 5 μm analytical column, containing mobile phase of Phosphate buffer (0.02 M), methanol, and acetonitrile [50:30:20 % v/v]. The method was run at 1 ml·min<sup>-1</sup> at 210 nm for Bimatoprost and 295 nm for Timolol for detection. The drug was eluted at 10.81 min for Bimatoprost and 3.77 min for Timolol. After developing the method, it was assured for the intended use by validation, which was done according to ICH Q2B guidelines. The analytical parameters checked were Specificity/Selectivity, linearity, Range, accuracy, ruggedness, and robustness. It was observed that the response of the detector was linear in the range of 6 - 18 μg/ml with a correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability-indicating assay method was established by using the samples generated by the forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative, and photolytic degradation, and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the quantitative analysis of Bimatoprost 0.3% + Timolol 0.5% Ophthalmic Solution drugs for pharmaceutical use. Currently, there is no official method for Bimatoprost & Timolol combination products in USP or BP. Available research work related to single Bimatoprost or Timolol products was not suitable for testing Bimatoprost and Timolol combination drugs. Additionally, there is no stability-indicating method to test Bimatoprost & Timolol combination products which insist us to do research and develop a new reverse phase-HPLC indicating method which will be faster and more accurate.展开更多
Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressur...Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.展开更多
With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight ...With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight groups. All these pesticide residues were detected in fish meat samples. All these pesticide residues except isoproturon were identified in soil sediments, whereas all these pesticide residues except isoproturon, carbaryl and DDE were also present in water samples. DDT, heptachlor, β-endosulfan, chlorpyrifos, dimethoate, captan, cypermethrin, chlorobromuron and chlorotoluron were absent in all samples of water, sediments and fish flesh. The pesticide residues levels were in order of parathion methyl 〉 DDE 〉 carbofuran 〉 atrazine 〉 α-endosulfan 〉 isoproturan 〉 carbaryl. The concentrations of pesticides were higher in fish weighing 800 -1 300 g than in those weighing 250 -750 g. The DDE was remained highest in sediments, while that was not detected in water samples. The pesticides (endosulfan, parathion methyl, atrazine and carbofuran) had crossed their MRL values (0.001 μg/g) in water samples.展开更多
The reverse martensitic transformation of TiNi alloy wires prestrained in the parent phase was studied. Experimental results shou, that the reverse transformation of the TiNi allogys prestrained in the parent phase is...The reverse martensitic transformation of TiNi alloy wires prestrained in the parent phase was studied. Experimental results shou, that the reverse transformation of the TiNi allogys prestrained in the parent phase is significantly different from that of the TiNi alloys prestrained in the martensite phase. Three continual peaks appear on the DSC curves of wires with a small prestrain and one high temperature peak appears on the DSC curves of wires with a large prestrain.展开更多
In marine seismic exploration,ocean bottom cable technology can record multicomponent seismic data for multiparameter inversion and imaging.This study proposes an elastic multiparameter lease-squares reverse time migr...In marine seismic exploration,ocean bottom cable technology can record multicomponent seismic data for multiparameter inversion and imaging.This study proposes an elastic multiparameter lease-squares reverse time migration based on the ocean bottom cable technology.Herein,the wavefield continuation operators are mixed equations:the acoustic wave equations are used to calculate seismic wave propagation in the seawater medium,whereas in the solid media below the seabed,the wavefields are obtained by P-and S-wave separated vector elastic wave equations.At the seabed interface,acoustic–elastic coupling control equations are used to combine the two types of equations.P-and S-wave separated elastic migration operators,demigration operators,and gradient equations are derived to realize the elastic least-squares reverse time migration based on the P-and S-wave mode separation.The model tests verify that the proposed method can obtain high-quality images in both the P-and S-velocity components.In comparison with the traditional elastic least-squares reverse time migration method,the proposed method can readily suppress imaging crosstalk noise from multiparameter coupling.展开更多
文摘The knowledge of the pathogenesis of type 1 diabetes mellitus(T1DM)continues to rapidly evolve.The natural course of the disease can be described in four clinical stages based on the autoimmune markers and glycemic status.Not all individuals of T1DM progress in that specific sequence.We hereby present a case of T1DM with a classical third phase(honeymoon phase)and discuss the intri-cacies of this interesting phase along with a possible future promise of“cure”with the use of immunotherapies.We now know that the course of T1DM may not be in only one direction towards further progression;rather the disease may have a waxing and waning course with even reversal of type 1 diabetes concept being discussed.The third phase popularly called the“honeymoon phase”,is of special interest as this phase is complex in its pathogenesis.The honeymoon phase of T1DM seems to provide the best window of opportunity for using targeted therapies using various immunomodulatory agents leading to the possibility of achieving the elusive“diabetes reversal”in T1DM.Identifying this phase is therefore the key,with a lot of varying criteria having been proposed.
基金supported by the National Natural Science Foundation of China(Nos.52201203 and 52171107)the Hebei Provincial Natural Science Foundation,China(No.E2021501026)+1 种基金the National Natural Science Foundation of China-Joint Fund of Iron and Steel Research(No.U1960204)the“333”Talent Project of Hebei Province,China(No.B20221001).
文摘Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.
基金Natural Science Foundation of Hunan Province (No.2020JJ4734)High Performance Computing Center of Central South University。
文摘The thermodynamic instability of zinc anodes in aqueous electrolytes leads to issues such as corrosion,hydrogen evolution reactions(HER), and dendrite growth, severely hindering the practical application of zinc-based aqueous energy storage devices. To address these challenges, this work proposes a dualfunction zinc anode protective layer, composed of Zn-Al-In layered double oxides(ILDO) by rationally designing Zn-Al layered double hydroxides(Zn-Al LDHs) for the first time. Differing from previous works on the LDHs coatings, firstly, the ILDO layer accelerates zinc-ion desolvation and also captures and anchors SO_(4)^(2-). Secondly, the in-situ formation of the Zn-In alloy phase effectively lowers the nucleation energy barrier, thereby regulating zinc nucleation. Consequently, the zinc anode with the ILDO protective layer demonstrates long-term stability exceeding 1900 h and low voltage hysteresis of 7.5 m V at 0.5 m A cm^(-2) and 0.5 m A h cm^(-2). Additionally, it significantly enhances the rate capability and cycling performance of Zn@ILDO//MnO_(2) full batteries and Zn@ILDO//activated carbon zinc-ion hybrid capacitors.This simple and effective dual-function protective layer strategy offers a promising approach for achieving high-performance zinc-ion batteries.
文摘Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.
基金Supported by Project of National Natural Science Foundation(21162030)
文摘[Objectives] To establish the high performance liquid chromatography( HPLC) determination method for oxysophocarpine and optimize the extraction and purification technology of oxysophocarpine from Sophora alopecuroides by inverse three-phase membrane cycle.[Methods]Based on the single-factor experiment,the effects of aqueous phase and organic phase volume ratio,the concentration of sodium hydroxide,concentration of hydrochloric acid and extraction cycle time on extraction process of oxysophocarpine were investigated using orthogonal design method,to determine the optimal extraction process. [Results]The oxysophocarpine was determined by Shim-pack VP-ODS chromatographic column( 4. 6 mm × 250 mm,5 μm),mobile phase was methanol-0. 2% phosphoric acid aqueous solution( 7∶ 93),gradient elution,flow rate was 1 m L/min,the sample size was 5 μm,column temperature was 30℃,detection wavelength was 221 nm. Aqueous phase and organic phase volume ratio was 1∶ 1,hydrochloric acid concentration was 0. 3 mol/L,sodium hydroxide concentration was 0. 75 mol/L,water pump flow rate was 6 m L/min,60 min cycle time. The extraction rate of oxysophocarpine 98. 21 % within 60 min under the best experimental conditions. Oxysophocarpine has good linearity relationship within the range of 0. 01-0. 7 mg/m L( r^2= 0. 9978,n = 6),the respective average recovery rate was 97. 47%( RSD = 1. 95%). [Conclusions] This extraction process is simple in operation,the organic solvent has low consumption,and can be used for extraction of alkaloid.
文摘High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A isolated from the leaves of Stevia rebaudiana using Reversed-Phase (RP) column. Using RP-HPLC method, the individual retention times for nine naturally occurring ent-kaurane diterpene glycosides of S. rebaudiana reported in JECFA have been determined at four different temperatures: 20℃, 40℃, 60℃, and 79℃. Also, calculated the relative retention times of the eight steviol glycosides steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A against the major steviol glycoside rebaudioside A. HPLC results suggested that temperatures 40℃ and 60℃ would be ideal conditions for better separation of steviol glycosides.
基金funded by Project FIS:PI10/00201 (Instituto Carlos III, Ministerio de Economía y Competitividad, Spain)partially supported by European Regional Development Funds (ERDF)
文摘Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per- formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor- mance liquid chromatography with diode array detection ((RP)HPLC/DAD) is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo- nization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci- sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre- hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de- monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc- cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.
文摘A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromatography was performed on a Purospher? Star, C18 (5 mm, 250 × 4.6 mm) column using acetonitrile: buffer (0.01 mM) (40:60, v/v, pH adjusted to 3.0), as a mobile phase. The mobile phase was pumped at a flow rate of 1.0 mL·min-1 and UV detection was performed at 240 nm. The method was validated for linearity, accuracy, precision and specificity. The method was applied to study the interaction between amlodipine and H1-receptor antagonists. These interactions were carried out in simulated gastric juice (pH 1), simulated full stomach (pH 4), blood pH (pH 7.4) and simulating GI (pH 9). The interacting drugs were heated at 37℃ with intermit-tent shaking and the samples were withdrawn every thirty minutes for three hours and drug contents were analyzed by RP-HPLC techniques. In most cases the in vitro availability of amlodipine was decreased. It was observed that the change in in vitro availability was pH dependent.
文摘The research was carried out for establishing a new reverse phase-HPLC stability indicating method for the quantification of Rucaparib. The experiment was determined on Waters HPLC instrument using 996 photo-diode array detector. The separation was done by using symmetry C-18 ODS (25 cm × 0.46 cm internal diameter) 5 μm analytical column containing mobile phase of Phosphate buffer (0.02 M) and methanol [65:35% v/v] adjusted pH to 4.8 by adding dilute ortho phosphoric acid. The method was run at 1 ml·min<sup>-1</sup> at 286 nm detection. The drug was eluted at 5.484 min. After developing the method, it was assured for the intended use by validation which was done according to ICH Q2B guidelines. The analytical parameters checked were linearity, accuracy, repeatability, intermediate precision, limit of detection, limit of quantitation, ruggedness and robustness. It was observed that the response of the detector was linear in the range of 6 - 14 μg/ml with correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability indicating assay method was established by using the samples generated by forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative and photolytic degradation and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the analysis of quality of the rucaparib drug.
文摘Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.
文摘A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.
基金Supported by the National Natrual Science Foundation of China
文摘The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.
基金Supported by the Key Science and Technology Program of Shaanxi Province,China(No.2015SF146).
文摘AIM:To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography(RP-HPLC),and to evaluate the retinal neuroprotective effect after topical administration with moxonidine in a high intraocular pressure(IOP)model.METHODS:The eyes of albino rabbits were administered topically and ipsilaterally with 0.2%moxonidine.A RPHPLC method was employed for the identification and quantification of moxonidine between 2 and 480 min,which presented in the aqueous humor and iris-ciliary body.Flash electroretinography(F-ERG)amplitude and superoxide dismutase(SOD)level were measured between day 1 and day 15 after topical administration with moxonidine in a rabbit model of high IOP.Histological and ultrastructural observation underwent to analyze the changes of retinal morphology,the inner retinal layers(IRL)thickness,and retinal ganglion cell(RGC)counting.RESULTS:Moxonidine was detectable between 2 and 480 min after administration,and the peak concentration developed both in the two tissues at 30 min,0.51μg/m Lin aqueous humor and 1.03μg/g in iris-ciliary body.In comparison to control,F-ERG b-wave amplitude in moxonidine eyes were significantly differences between day 3 and day 15(P<0.01)in the high IOP model;SOD levels were significantly higher at all time-points(P<0.01)with a maximum level of 20.29 U/mgprot at day 15;and RGCs were significantly higher(P<0.05).CONCLUSION:Moxonidine is a viable neuroprotective agent with application to high IOP model.All layers of retina,including RGC layer,retinal nerve fiber layer and INL,are more preserved after moxonidine administration.SOD plays a neuroprotective role in ocular hypertension-mediated RGC death.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA11030404),the Key Project from Chinese Academy of Sciences(KGZD-EW-606)the National Natural Science Foundation of China(21302199)Guangzhou Science and Technology Plan Projects(201510010012)
文摘We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein,we have investigated the use of MT6 in stereo-selective biocatalysis through direct hydrolysis reactions.Notably,the stereo-selectivity of MT6 was also demonstrated to be opposite to that of other common lipases in hydrolysis reactions.Parameters,including temperature,organic co-solvents,pH,ionic strength,catalyst loading,substrate concentration,and reaction time,affecting the enzymatic resolution of racemic 1-phenylethyl acetate were further investigated,with the e.e.of the final(S)-l-Phenylethanol product and the conversion being 97%and 28.5%,respectively,after process optimization.The lengths of side chains of 1-phenylethyl esters greatly affected the stereo-selectivity and conversion during kinetic resolutions.MT6 is a novel marine microbial GDSL lipase exhibiting opposite stereo-selectivities than other common lipases in both trans-esterification reactions and hydrolysis reactions.
文摘The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency and their quality to improve the human health care. Isotretritoin finds its applications in the maintenance of epithelial tissues. Different processes to date such as normal phase HPLC, or gas chromatrography am- ong others are able to separate and quantify isote- troin. However, the extraction is quite complex and in the case of HPLC, the analysis requires long retention times. In such context, an isocratic reversed- phase high-performance liquid chromatography (HP- LC) technique coupled with an UV-vis detector is described here for easy separation and quantification of 13-cis-retinoic (isotretinoin) from soft gelatin capsule formulations. The isotretinoin was extracted from three different commercial drug samples with tetrahydrofuran (THF) solvent by a procedure that can be completed in less than 10 minutes. Subsequent separation and quantification were accomplished in less than 5 minutes under isocratic reversed-phase conditions on a Lichrospher RP18 column and a mobile phase consisting of 0.01% TFA/acetonitrile (15/85, v/v) at a flow rate of 1.0 mL/min. Isotretoin was detected for the three samples via its UV-vis absorbance at 342 nm. The method was validated and the results showed good linearity, precision and accuracy for sensitive and selective quantitative determination of isotretinoin in the different pharmaceutical formulations. We found that the average isotretinoin content in two of the three commercial pro- ducts fell outside the 90-110% United States Pha- rmacopeia specifications. Consequently, the facile extraction and the precise method for the biomole- cule quantification open up tremendous possibilities in improving the quality control of drugs which can exist as different generic brands.
文摘The research was carried out to establish a new reverse phase-HPLC stability indicating method for quantifying Bimatoprost & Timolol in ophthalmic solution. The experiment of Bimatoprost & Timolol in ophthalmic solution method development was determined on Waters HPLC instrument using a UV Detector. The separation was done by using L11, Zorbex SB phenyl (4.6 mm × 250 mm internal diameter) 5 μm analytical column, containing mobile phase of Phosphate buffer (0.02 M), methanol, and acetonitrile [50:30:20 % v/v]. The method was run at 1 ml·min<sup>-1</sup> at 210 nm for Bimatoprost and 295 nm for Timolol for detection. The drug was eluted at 10.81 min for Bimatoprost and 3.77 min for Timolol. After developing the method, it was assured for the intended use by validation, which was done according to ICH Q2B guidelines. The analytical parameters checked were Specificity/Selectivity, linearity, Range, accuracy, ruggedness, and robustness. It was observed that the response of the detector was linear in the range of 6 - 18 μg/ml with a correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability-indicating assay method was established by using the samples generated by the forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative, and photolytic degradation, and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the quantitative analysis of Bimatoprost 0.3% + Timolol 0.5% Ophthalmic Solution drugs for pharmaceutical use. Currently, there is no official method for Bimatoprost & Timolol combination products in USP or BP. Available research work related to single Bimatoprost or Timolol products was not suitable for testing Bimatoprost and Timolol combination drugs. Additionally, there is no stability-indicating method to test Bimatoprost & Timolol combination products which insist us to do research and develop a new reverse phase-HPLC indicating method which will be faster and more accurate.
文摘Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.
文摘With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight groups. All these pesticide residues were detected in fish meat samples. All these pesticide residues except isoproturon were identified in soil sediments, whereas all these pesticide residues except isoproturon, carbaryl and DDE were also present in water samples. DDT, heptachlor, β-endosulfan, chlorpyrifos, dimethoate, captan, cypermethrin, chlorobromuron and chlorotoluron were absent in all samples of water, sediments and fish flesh. The pesticide residues levels were in order of parathion methyl 〉 DDE 〉 carbofuran 〉 atrazine 〉 α-endosulfan 〉 isoproturan 〉 carbaryl. The concentrations of pesticides were higher in fish weighing 800 -1 300 g than in those weighing 250 -750 g. The DDE was remained highest in sediments, while that was not detected in water samples. The pesticides (endosulfan, parathion methyl, atrazine and carbofuran) had crossed their MRL values (0.001 μg/g) in water samples.
基金Funded by the National Natural Science Foundation of China(No.50071037)
文摘The reverse martensitic transformation of TiNi alloy wires prestrained in the parent phase was studied. Experimental results shou, that the reverse transformation of the TiNi allogys prestrained in the parent phase is significantly different from that of the TiNi alloys prestrained in the martensite phase. Three continual peaks appear on the DSC curves of wires with a small prestrain and one high temperature peak appears on the DSC curves of wires with a large prestrain.
基金supported by National Natural Science Foundation of China(Nos.41904101,41774133)Natural Science Foundation of Shandong Province(ZR2019QD004)+1 种基金Fundamental Research Funds for the Central Universities(No.19CX02010A)the Open Funds of SINOPEC Key Laboratory of Geophysics(Nos.wtyjy-wx2019-01-03,wtyjywx2018-01-06)
文摘In marine seismic exploration,ocean bottom cable technology can record multicomponent seismic data for multiparameter inversion and imaging.This study proposes an elastic multiparameter lease-squares reverse time migration based on the ocean bottom cable technology.Herein,the wavefield continuation operators are mixed equations:the acoustic wave equations are used to calculate seismic wave propagation in the seawater medium,whereas in the solid media below the seabed,the wavefields are obtained by P-and S-wave separated vector elastic wave equations.At the seabed interface,acoustic–elastic coupling control equations are used to combine the two types of equations.P-and S-wave separated elastic migration operators,demigration operators,and gradient equations are derived to realize the elastic least-squares reverse time migration based on the P-and S-wave mode separation.The model tests verify that the proposed method can obtain high-quality images in both the P-and S-velocity components.In comparison with the traditional elastic least-squares reverse time migration method,the proposed method can readily suppress imaging crosstalk noise from multiparameter coupling.