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Recombinant proteins hold significant importance in numerous disciplines. As the demand for expressing and purifying these proteins grows, the scientific community is in dire need of a simple yet versatile methodology that can efficiently purify these proteins. Aptamers as synthetic nucleic acid–based ligands with high affinity have shown promise in this regard, as they can capture targets through molecular recognition. In this study, novel aptamer‐functionalized polydopamine‐coated magnetic graphene oxide nanocomposites were facilely prepared, achieving an impressive average aptamer coverage density (45 nmol/mg). These nanocomposites exhibited a uniform structure and robust magnetic responsiveness. The findings indicated that they possess several advantages, such as rapid adsorption, substantial capacity (171.4 mg/g), and excellent reusability. Notably, due to the inherent properties of nucleic acids, the immobilized aptamer‐magnetic beads can be utilized repeatedly with high purification efficiency. Finally, the nanocomposites were further employed to purify His‐tagged proteins from actual samples. Remarkably, they were able to selectively and efficiently isolate His‐tagged retinoid X receptor alpha protein from complex Escherichia coli lysate. The purified His‐tagged retinoid X receptor alpha protein was analyzed using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. This confirmed the efficacy of developed nanocomposites, reinforcing their vast potential for purification of His‐tagged recombinant proteins. [ABSTRACT FROM AUTHOR]

The integration of shared bikes and flexible transit services offers significant potential and benefits for urban transit systems. This paper presents a novel robust optimization framework for designing demand responsive connectors (DRC) that are fed by shared bikes. A two-stage model is formulated, with the first stage focusing on prereserved requests and the second stage addressing en-route random requests. The findings demonstrate that incorporating shared bikes can enhance the efficiency of serving en route late requests and reduce the required DRC vehicle fleet size. Additionally, it is observed that e-bikes are particularly suitable for this joint service due to their adaptability. [ABSTRACT FROM AUTHOR]

AbstractAs an important circulating metabolite in the body, the accurate determination of glucose in body fluids is very important for the evaluation of physiological status. However, liquid chromatography–mass spectrometry (LC–MS) methods present challenges for glucose due to poor ionization combined with weak chromatographic retention. Here, a method for determining salivary glucose using LC–MS after derivation by dibenzylamine is described in which 3-O-methyl-D-glucopyranose was used as internal standard. Saliva samples were prepared by protein precipitation, and the analytes were separated on a polar-copolymerized C18 reversed phase column. Detection took place by high-resolution orbitrap mass spectrometry after ionization in the positive mode. The calibration function was linear from 0.35 to 50 ng/mL. The recoveries were from 97.82 to 104.51% for intraday assays and 98.96 to 106.61% for interday assays. The intraday precision of salivary glucose was from 0.37% to 1.43% and the interday precision from 1.33% to 1.43%. The limits of detection and quantification in saliva were 0.2 and 0.6 ng/mL. The samples after derivatization were stored at 4 °C and 25 °C and analyzed every two days with five repeats. The relative standard deviations were 0.09% and 0.27% at 4 °C and 25 °C. This method was employed for the determination of the glucose in saliva for healthy male college students after exercise. [ABSTRACT FROM AUTHOR]

The mevalonate (MVA) pathway is a central metabolic route that converts mevalonate into isoprenoids, which are of crucial significance in various cellular processes. As no systematic approach had been developed and validated for the simultaneous estimation of these intermediate metabolites within the MVA pathway. In this research, a method was developed for the concurrent determination of 7 key intermediate metabolites in the MVA pathway based on ultra-high performance liquid chromatography (UPLC) coupled with a quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (HRMS). The developed UPLC-HRMS method based on the hydrophilic interaction liquid chromatography (HILIC) separation mode was successfully applied to the quantitative analysis of relevant key intermediate metabolites in wild type Escherichia coli (E. coli) BL21 (DE3) and the recombinant E. coli BL21(DE3) system constructed by introducing all the genes of the MVA pathway into the strain. The above results can offer a reference for further studies on the MVA pathway., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier Inc.)