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Expression of TFRC helps to improve the antineoplastic effect of Ara-C on AML cells through a targeted delivery carrier
Currently, high doses of cytarabine arabinoside (Ara-C)-based combined chemotherapy are commonly used in acute myeloid leukemia (AML) therapy, but severe adverse effects and poor suppression effects in leukemia cells limit the clinical therapeutic efficiency of Ara-C-based chemotherapy due to a lack of targeting selectivity. To improve the therapeutic effect of Ara-C in AML, here, since we confirmed that transferrin receptor 1 (TFRC) expression in AML cells was constant, we generated Ara-C@HFn by encapsulating free Ara-C into self-assembled heavy ferritin chain (HFn, the ligand of TFRC) nanocages
壳聚糖盐酸盐稳定乳液的制备及免疫效果分析
为了解决油乳佐剂在诱导细胞免疫方面的不足,引入正电荷的壳聚糖盐以稳定乳液,从而提升细胞免疫应答。本研究选取卵清蛋白为模式抗原,分别制备了单抗原疫苗、商品佐剂疫苗和乳液疫苗,表征了乳液的粒径、电势及抗原吸附率等参数。通过肌肉注射免疫BALB/c小鼠,检测免疫后抗体和细胞因子的分泌水平、淋巴细胞的活化水平以评价乳液的免疫效果。结果显示壳聚糖盐酸盐可有效稳定乳液,其粒径在600nm左右,荷正电并对抗原吸附率达90%以上。免疫动物后,该乳液可有效提升血清特异性抗体水平并增强IL-4的分泌,显著提高抗原特异性CD8~+ T细胞的比例,提升细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)表面活化分子的表达水平,诱导高效的细胞免疫应答。此外,乳液能够有效提高记忆T细胞(CD44~+CD62L~+)的水平。综上所述,以壳聚糖盐酸盐稳定的乳液为佐剂能有效提升体液及细胞免疫效果,并有望起长期保护作用
科学数据语义关联技术研究与应用
【目的】在数据密集型和融合科学新范式下,迫切需要传统的数据共享服务向数据知识化服务转化,使用语义关联技术在海量科学数据间进行知识组织、关联、发现正是解决这个问题的核心路径。【方法】本文对国内外数据关联技术总体现状、领域应用研究进展进行了广泛调研,对结构化数据关联发布、长文本语义挖掘和数据关联融合服务等关键技术进行了深入研究,初步实现了领域科学数据的关联化组织发布和语义化融合服务。【结果】在化学、植物及微生物数据中心展开应用实践,验证了科学数据语义关联融合技术是实现数据知识化服务的可行且重要手段。【结论】未来由各领域数据中心建立起来的科学数据关联融合网络将成为服务科研新范式需求的重要数据基础设施
枯草芽孢杆菌聚谷氨酸合成途径相关基因功能研究
聚谷氨酸(polyglutamic acid, PGA)作为一种天然多功能的聚合物,近年来成为研究的热点。由于很难通过化学方法合成,微生物发酵是目前生产聚谷氨酸的有效途径。【目的】从基因水平探究枯草芽孢杆菌聚谷氨酸合成途径中degS、degQ、degU、swrA、rocA、putM基因的功能,通过分子改造实现对代谢途径的调控。【方法】以枯草芽孢杆菌为出发菌株,通过对代谢途径中相关基因进行敲除或过表达,分别构建degS、degQ和degU基因缺失的重组菌,swrA、rocA和putM基因过表达的重组菌,借助菌株胞外聚谷氨酸积累的变化分析影响途径的关键节点。【结果】在摇瓶发酵条件下,重组菌Bacillus subtilis 168-swrA、Bacillus subtilis 168-rocA、Bacillus subtilis 168-putM的胞外聚谷氨酸含量分别是原始菌株的1.28倍、1.47倍和1.37倍。重组菌Bacillus subtilis 168-ΔdegS、Bacillus subtilis 168-ΔdegQ、Bacillus subtilis 168-ΔdegU的胞外聚谷氨酸含量分别是原始菌株的1.01倍、0.98倍和0.94倍。在静态培养时,BS168-ΔdegU不能形成完整的生物膜,Bacillus subtilis 168-ΔdegS、Bacillus subtilis 168-ΔdegQ、Bacillus subtilis 168-swrA、Bacillus subtilis 168-rocA和Bacillus subtilis 168-putM菌株的生物膜形成量分别是原始菌株的1.48倍、1.31倍、1.77倍、2.59倍和2.16倍,且胞外蛋白含量与生物膜的形成量呈正相关。【结论】degS、degQ和degU基因的缺失不会明显影响聚谷氨酸的合成,swrA、rocA和putM基因的过表达均能显著提升细胞合成聚谷氨酸的能力,rocA和putM基因的表达量增强能提高胞内谷氨酸的积累,从而增加聚谷氨酸的合成
Analysis and experiment of sintering and densification of magnesia particles
Magnesia densification is essential for Mg-based refractories and materials to attain better thermal per-formance and longer service life. Few industrial-scale processes can produce magnesia with the required bulk density of above 3.40 g/cm3 (or relative density of over 95 %) from natural magnesites. The inability to achieve the desired densification is related to the low heat transfer between gas and solids inherent in large-sized greenbodies typically sintered in industrial shaft kilns. This study proposes sintering particles of 0-6 mm in primary sizes corresponding to those employed in most refractory end-products of sintered magnesia. Microstructures of the sintered particles are analyzed, and the underlying sintering mecha-nisms are discussed. The sintering of small particles can achieve over 95 % of densification at 1300- 1600 degrees C for less than 10 min. This study provides an alternative approach to producing high-density mag-nesia with the potential for substantial reductions in energy consumption and carbon emissions.(c) 2022 Elsevier Ltd. All rights reserved
Constructing BaTiO3/TiO2@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties
BaTiO3/TiO2@polypyrrole (PPy) composites with hollow multishelled structure (HoMS) were constructed to enhance the electromagnetic wave absorbing properties of BaTiO3-based absorbing material. BaTiO3/TiO2 HoMSs were prepared by hydrothermal crystallization using TiO2 HoMSs as template. Then, FeCl3 was introduced to initiate the oxidative polymerization of pyrrole monomer, forming BaTiO3/TiO2@PPy HoMSs successfully. The electromagnetic wave absorbing properties of BaTiO3/TiO2 HoMSs and BaTiO3/TiO2@PPy HoMSs with different shell number were investigated using a vector network analyzer. The results indicate that BaTiO3/TiO2@PPy HoMSs exhibit improved microwave absorption compared with BaTiO3/TiO2 HoMSs. In particular, tripled-shelled BaTiO3/TiO2@PPy HoMS has the most excellent absorbing performance. The best reflection loss can reach up to -21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm, and the qualified absorption bandwidth of tripled-shelled BaTiO3/TiO2@PPy HoMS is up to 4.2 GHz. This work paves a new way for the development of high-performance composite microwave absorbing materials