The flexible and controlled synthesis of metal–organic framework (MOF)-derived hybrid nanostructures is of great significance in fine tuning of their enrichment performance in large-scale and in-depth phosphoproteome analysis. Herein, a magnetic guanidyl-functionalized MOF hybrid coating with multiaffinity sites, denoted as Fe3O4@G-ZIF-8, was fast fabricated via a one-pot epitaxial growth strategy for the first time and applied for selective and highly efficient enrichment of global phosphopeptides. The intrinsic unsaturated metal sites of ZIF-8 endow the surface-mounted MOF coatings with immobilized metal ion affinity chromatography interaction with multiphosphorylated peptides. The oriented anchoring of bifunctional guanidineacetic acid on the magnetic MOF nanospheres provides additional affinity sites (guanidyl groups) for specific recognition of phosphopeptides by "salt bridge" interaction, as well as active site carboxyl groups for the coordination with the metal ions. The as-prepared Fe3O4@G-ZIF-8 exhibits large surface area (382.5 m2 g–1), good superparamagnetic property (41.6 emu g–1) and stability, and size-exclusion effect (1.73 nm), which can serve as a specific adsorbent for global phosphopeptide analysis with satisfactory selectivity, great detection sensitivity (1 fmol), and rapid magnetic separation. Moreover, the successful application of Fe3O4@G-ZIF-8 for selective capture of both multi- and mono-phosphopeptides from human saliva and serum demonstrated the great potential of magnetic surface-mounted MOF coatings in effective identification of low-abundance phosphopeptides by matrix-assisted laser desorption ionization time-of-flight mass spectrometry from complicated biological matrices.
This study investigated the clinical value of MRI T2WI for VPI in early-stage NSCLC. Four MRI signs of VPI in lung cancer were summarized by MR T2WI of patients with early-stage NSCLC suspected of VPI. Among them, category 3 signs and category 4 signs had higher positive predictive values. This indicates that T2WI is useful in the prediction of VPI in early-stage NSCLC.
Objective To research the absorption mechanism of paeoniflorin across Caco-2 monolayer model. Methods Depending on the Caco-2 cell monolayers drug transport model to study the double transport mechanism of paeoniflorin. To explore the effect of paeoniflorin absorption by time and drug concentration, the drug concentration was determined through the use of HPLC instrument and the Papp was calcalatad. Results In the Caco-2 monolayer model, the transport of paeoniflorin form Apical (AP) to Basolateral (BL) is similar to the transport form BL to AP. Conclusion The main mechanism of the paeoniflorin intestinal absorption in the Caco-2 monolayer model is passive transference.
Land use in karst areas affects soil properties, impacting carbon sinks. Accurate estimation of carbon sink flux in karst areas through zoning and classification is crucial for understanding global carbon cycling and climate change. The peak cluster depression is the largest continuous karst landform region in southern China, with the depressions primarily covered by farmland and influenced by agricultural activities. This study focused on the Guancun Underground River Basin, a typical peak cluster depression basin, where sampling and analysis were conducted during the agricultural period of 2021–2022. Using hydrochemical analysis and isotopic methods, the results indicated that: (1) The primary hydrochemical type in the Guancun Underground River Basin is HCO3-Ca, with hydrochemical composition mainly controlled by carbonate rock weathering. (2) The primary sources of Cl−, SO42−, and NO3− are agricultural activities, with agriculture contributing 0.68 mmol/L to dissolved inorganic carbon (DIC), accounting for about 13.86%, as confirmed by ion concentration analysis and isotope verification. (3) The size of the depression area is proportional to the contribution of agricultural activities to DIC, while also being influenced by dilution effects. A comparison was made regarding the contribution of other land use types to DIC. The impact of land use on DIC in karst processes should not be overlooked, and zoning and classification assessments of carbon sink flux under different influencing factors contribute to carbon peaking and carbon neutrality goals.
A method for the determination of the content of olive oil in olive blend oil by headspace gas chromatography-mass spectrometry (SH-GC/MS) was established. The amount of the sample, the heating temperature, the heating time, the amount of injection, the injection mode and the chromatographic column were optimized. The characteristic compounds of olive oil were found by chemometric method. A sample of 1.0 g was placed in a 20 mL headspace flask, and heated at 180℃ for 2700 s. Then, 1.0 mL headspace gas was taken into the instrument. An HP-88 chromatographic column was used for the separation and the analysis was performed by GC/MS. The results showed that the linear range was 0-100%(olive oil content). The linear correlation coefficient (r2) was more than 0.995, and the limits of detection were 1.26%-2.13%. The deviations of olive oil contents in the olive blend oil were from -0.65% to 1.02%, with the relative deviations from -1.3% to 6.8% and the relative standard deviations from 1.18% to 4.26% (n=6). The method is simple, rapid, environment friendly, sensitive and accurate. It is suitable for the determination of the content of olive oil in olive blend oil.
Objective: To establish a simultaneous determination method for four alkaloids in kuhuang injection.Methods: A high-performance liquid chromatography(HPLC) was used to simultaneously determine the contents of four alkaloids on line.The best mobile phase composition,flow rate and detection wavelength were optimized through experiments.Results: All calibration curves of the 4 alkaloids showed good linear regression within the test range.The method showed good precision,stability,reappearance and high-efficiency analysis.Conclusion: The method is easy and accurate and can be used in the simultaneous determination of the four alkaloids in Kuhuang injection and is good for the quality control of Kuhuang injection.
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