Tetracycline (TET) is a broad-spectrum antibiotic, which is frequently used in the prevention and treatment of animal diseases, feed additives, and so on. However, its residue and accumulation in animal-derived foods could cause several side effects to the human body. Herein, we fabricated TET aptamerpendant DNA tetrahedral nanostructure-functionalized magnetic beads (Apt-tet MBs) as a probe to detect TET. In the presence of target TET, DNA primer was released from Apt-tet MBs since the TET aptamer could specifically bind TET. Next, the separated DNA primer could effectively initiate rolling circle amplification (RCA) reaction and generate a long tandem single-stranded sequence. Finally, with SYBR Green I as the fluorescence dye, the fluorescence signal could be detected by detection probes through hybridizing the RCA product. Under optimal conditions, the fluorescent signal increased with the increasing target TET concentration within the 5 orders of magnitude dynamic range from 0.001 to 10 ng mL −1 . The detection limit was calculated to be 0.724 pg mL −1 and the method showed high selectivity toward TET among different antibiotics. More impressively, this method was employed for TET determination in fish and honey samples. The as-obtained results were consistent with those of ELISA kits, holding great potential in the field of food analysis.
Chimeric antigen receptor (CAR)-T cell therapy has been shown to have considerable therapeutic effects in hematological malignancies, and NKG2D(z) CAR-T cell therapy has been verified to be safe based on clinical trials. However, due to the poor persistence of NKG2D(z) CAR-T cells, their therapeutic effect is not obvious. Here, we constructed NKG2D(bbz) CAR-T cells that can simultaneously activate 4-1BB and DAP10 costimulatory signaling. They were found to be cytotoxic to the target cells in vitro and in vivo. They exhibited low differentiation, low exhaustion, and good proliferation. Importantly, the proportions of central memory T (Tcm) and stem cell-like memory T (Tscm) cell subsets were strikingly increased. After long-term incubation with the target cells, they displayed reduced exhaustion compared to NKG2D(z) CAR-T cells. Further, in the presence of the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, they exhibited reduced exhaustion and apoptosis, upregulated Bcl2 expression, and an increased proportion of Tcm cell subsets. Finally, NKG2D(bbz) CAR-T cells had better antitumor effects in vivo. In summary, the results showed that NKG2D(bbz) CAR-T cells may be valuable for cellular immunotherapy of cancer.
Liquid‐liquid two‐phase flow in a mixer of mixer‐settler has been studied via a computational fluid dynamics (CFD) simulation combined with the population balance model (PBM) and verified with particle image velocimetry (PIV) experiments. The simulation was performed using the multiple reference frame (MRF) approach, the Eulerian‐Eulerian two‐fluid model, and the standard k‐ϵ model. The effects of impeller speed, flow ratio, and impeller type on flow field, droplet diameter, and dispersed phase holdup were investigated. The results showed that CFD simulation combined with PBM could predict droplet size distribution (DSD). The smaller droplets were mainly in the bottom region of the mixer, larger ones were in the top part of the mixer, and the largest droplets appeared in the impeller centre region. The DSD and holdup were more sensitive to impeller speed than to the organic/aqueous flow ratio. A dual‐impeller mixer configuration was designed to enhance the mixing performance. Compared with single‐impeller, the installation of dual‐impellers could effectively avoid the dispersed phase dead zone above the lower impeller. When hc /T = 0.3, the best dispersing effect, such as uniform DSD and high mixing chamber space utilization, could be obtained.
In order to analyse the influence of Micro-channel circle of friends on college students' interpersonal communication, based on the evaluation models constructed in the respects of self-awareness, self expression, and self-image building, this thesis designs entropy value method to empower. It is to evaluate in the way of determining index weight according to the size of the information provided by the observation, and it has effectively promoted the interpersonal communication among college students for the influence of Micro-channel circle of friends on college students' self-awareness, self-expression, and self-image building is positively related according to the data got from statistical analysis of correlation and regression analysis.
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