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Magnetosomes intracellularly biomineralized by Magnetotactic bacteria (MTB) are membrane-enveloped nanoparticles of the magnetic minerals magnetite (Fe 3 O 4) or greigite (Fe 3 S 4). MTB thrive in oxic-anoxic interface and exhibit magnetotaxis due to the presence of magnetosomes. Because of the unique characteristic and bionavigation inspiration of magnetosomes, MTB has been a subject of study focused on by biologists, medical pharmacologists, geologists, and physicists since the discovery. We herein first briefly review the features of MTB and magnetosomes. The recent insights into the process and mechanism for magnetosome biomineralization including iron uptake, magnetosome membrane invagination, iron mineralization and magnetosome chain assembly are summarized in detail. Additionally, the current research progress in biotechnological applications of magnetosomes is also elucidated, such as drug delivery, MRI image contrast, magnetic hyperthermia, wastewater treatment, and cell separation. This review would expand our understanding of biomineralization and biotechnological applications of bacterial magnetosomes. [Display omitted] • General feature of magnetotactic bacteria and magnetosomes are reviewed. • Magnetosome mineralization processes and mechanism are proposed in detail. • Magnetosomes appear extensive applications in biomedicine and environment. • The prospects for future studies of bacterial magnetosomes were discussed. [ABSTRACT FROM AUTHOR]

This paper concerns the stationary subsonic or sonic–subsonic solution of the electric potential driven problem to the isentropic hydrodynamic model for semiconductors. We give a necessary and sufficient condition to ensure the existence of this kind of solution. Specifically, there exists a subsonic or sonic–subsonic solution to this problem if and only if 0 ≤ ϕ r ≤ ϕ ̄ , with the number ϕ ̄ = O 1 τ . Here, ϕ r is the right side electric potential and τ is the relaxation time. Moreover, there is a number ϕ ̃ ∈ (0 , ϕ ̄ ] such that when ϕ r = ϕ ̃ , there exists a sonic–subsonic solution. In this way, we show the influence of the relationship between the boundary value of the electric potential and the semiconductor effect on the existence of this kind of solution. Finally, we prove the uniqueness of subsonic solution by the energy method under the assumption that ϕ r and ϕ r τ are both small enough. [ABSTRACT FROM AUTHOR]

Fluoropyridine-based chemotherapy remains the most widely used treatment for colorectal cancer (CRC). In this study, we investigated the mechanism by which the natural product Scutellaria baicalensis (Huang Qin; HQ) and one of its main components baicalin enhanced 5-fluorouracil (5-FU) antitumor activity against CRC. Cell proliferation assays, cell cycle analysis, reverse-phase protein array (RPPA) analysis, immunoblot analysis, and qRT-PCR were performed to investigate the mechanism(s) of action of HQ and its active components on growth of CRC cells. HQ exhibited in vitro antiproliferative activity against drug resistant human CRC cells, against human and mouse CRC cells with different genetic backgrounds and normal human colon epithelial cells. In vivo animal models were used to document the antitumor activity of HQ and baicalin. The mechanism of growth inhibitory activity of HQ is due to inhibition of proliferative signaling pathways including the CDK-RB pathway. In addition, HQ enhanced the antitumor effects of 5-FU and capecitabine in vivo. Furthermore, we identified baicalin as an active component of HQ. The combination of baicalin and 5-FU demonstrated synergistic activity against 5-FU-resistant RKO-R10 cells. The combination significantly inhibited in vivo tumor growth greater than each treatment alone. RPPA results showed that the signaling pathway alterations in CRC cells were similar following HQ and baicalin treatment. Together, these results indicate that HQ and its component baicalin enhance the effect of 5-fluorouracil-based chemotherapy via inhibition of CDK-RB pathway. These findings may provide the rational basis for developing agents that can overcome the development of cellular drug resistance. 9Q3bw5kPrTjBvtYuEHSNma Video Abstract [ABSTRACT FROM AUTHOR]