No abstract

In this study, a new method/mechanism to manipulate ions in solution was developed, based on which liquid-phase ion trap was built. In this liquid-phase ion trap, ion manipulations conventionally performed in a quadrupole ion trap or in a trapped ion mobility spectrometer placed in a vacuum were achieved in solutions. Through theoretical derivation and numerical simulation, it is found that ions have different motional characteristics than those in vacuum. Instead of a radio frequency quadrupole electric field, tunable DC electric fields together with a constant liquid flow were applied to control ion motions in solution. Different ions could be trapped and focused in a potential well, and ion densities could be increased by over 100-fold. By adjusting the DC electric field of the potential well, trapped ions could be transferred into another trapping region or sequentially released for detection. Ions released from the liquid-phase ion trap were then detected by a mass spectrometer interfaced with an electrospray ionization source. Since the ion manipulation mechanism in solution is different and complementary to that in vacuum, the use of a liquid-phase ion trap could also boost detection sensitivity and the mixture analysis capability of a mass spectrometer.

No abstract

Current miniature mass spectrometers mainly focus on the analyses of organic and small biological molecules. In this study, we explored the possibility of developing high resolution miniature ion trap mass spectrometers for whole protein analysis. Theoretical derivation, GPU assisted ion trajectory simulation, and initial experiments on home‐developed “brick” mass spectrometer were carried out. Results show that ion‐neutral collisions have smaller damping effect on large protein ions, and a higher buffer gas pressure should be applied during ion trap operations for protein ions. As a result, higher pressure ion trap operation not only benefits instrument miniaturization, but also improves mass resolution of protein ions. Dynamic mass scan rate and generation of low charge state protein ions are also found to be helpful in terms of improving mass resolutions. Theory and conclusions found in this work are also applicable in the development of benchtop mass spectrometers.

Breast cancer (BC), the most commonly diagnosed invasive cancer in females globally, has upset human being for a long time. We used GEPIA2, bc-GenExMiner v4.8, cBioPortal database, Kaplan-Meier Plotter and TIMER2.0 to explore expressions, clinical features, mutations, prognosis and immune infiltrations of benzimidazole 1 (BUB1)/ benzimidazole 1 mitotic checkpoint serine or threonine kinase B (BUB1B)/ benzimidazole 3 (BUB3) of BC. Nomogram also used to give a more precise prognostic value of breast invasive carcinoma (BRCA). BUB1/BUB1B/BUB3 all demonstrate significant predictive values in the prognostic of OS in BRCA, especially that of BUB1B. Moreover, the predictive value of BUB1 is just the opposite to that of BUB1B and BUB3. GO/KEGG analyses were conducted to analyse the mechanisms in biology. STRING and GeneMANIA were used to depicted co-expression genes with BUB1/BUB1B/BUB3 and 5 Hub genes were found upregulated in BC for further analyses. Our results show that in BRCA the BUB1/BUB1B/BUB3 expressions are upregulated and the expressions of BUB1/BUB1B correlate with the stages. Some clinicopathological features of the expressions of BUB3 are just the opposite of that in BUB1 and BUB1B. cBioPortal analyses show that only the minority of samples in BRCA go through mutations. Survival analyses reveal that BUB1 and BUB1B overexpression are associated with poor prognosis in BC, while BUB3 seems to imply longer RFS in triple negative breast cancer (TNBC). Moreover, BUB1/BUB1B/BUB3 expressions negatively correlate with different types of immune cells, and positive relations can be observed just in BUB3. GO and KEGG analyses illustrate that BUB1/BUB1B/BUB3 participate in the processes of organelle fission, chromosomal region, ATPase activity, cell cycle and so forth. The 5 Hub genes imply poor prognosis. BUB1/BUB1B/BUB3 are potential new biomarkers for BC patients.