排序方式: 共有248条查询结果,搜索用时 15 毫秒
241.
Dr. Jiangao Li Dr. Miaomiao Kang Dr. Zhijun Zhang Dr. Xue Li Weilin Xu Prof. Dong Wang Prof. Xike Gao Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2023,62(20):e202301617
Integrating the ultralong excitation wavelength, high extinction coefficient, and prominent photothermal conversion ability into a single photothermal agent is an appealing yet significantly challenging task. Herein, a precise dual-acceptor engineering strategy is exploited for this attempt based on donor-acceptor (D-A) type semiconductor polymers by subtly regulating the molar proportions of the two employed electron acceptor moieties featuring different electronic affinity and π-conjugation degrees, and making full use of the active intramolecular motion-induced photothermal effect. The optimal polymer SP4 synchronously shows desirable second near-infrared (NIR-II) absorption, an extremely high extinction coefficient, and satisfactory photothermal conversion behavior. Consequently, the unprecedented performance of SP4 NPs on 1064 nm laser-excited photoacoustic imaging (PAI)-guided photothermal therapy (PTT) is demonstrated by the precise tumor diagnosis and complete tumor elimination. 相似文献
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高强度聚焦超声经颅脑肿瘤治疗焦域的仿真研究* 总被引:1,自引:1,他引:0
为了研究脑组织和脑肿瘤组织在HIFU治疗时形成焦域的特性及坏死肿瘤组织、不同治疗剂量参数以及多次治疗时焦点间距和时间间隔对HIFU形成焦域的影响,本文以脑胶质瘤患者为例,利用患者头颅CT图像数据建立HIFU经颅治疗的仿真模型,基于Westervelt声波非线性传播方程和Pennes生物热传导方程进行HIFU经颅治疗的仿真研究。结果表明,脑组织和脑肿瘤组织内形成HIFU焦域的差异较小,坏死肿瘤组织对HIFU温度场分布有较小影响;辐照声强越大,焦点温升达到同一温度所用时间越短,焦域长短轴越短,颅骨处温升越低;当焦点间距在一定范围内时,第一次辐照形成的温度场分布对第二个焦点温升达到同一温度所需时间影响较大;两次辐照时间间隔对颅骨处温升和两次聚焦形成60?C以上温度分布影响较小。 相似文献
243.
Guangcheng Wei Miaomiao Yan Renhao Dong Dong Wang Xiangzhu Zhou Jingfei Chen Prof. Dr. Jingcheng Hao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(46):14708-14716
Under acidic conditions, reduced graphene oxide (rGO) was functionalized with p‐aminobenzoic acid, which formed the diazonium ions through the diazotization with a wet‐chemical method. Surfactants or stabilizers were not applied during the diazotization. After the functionalized rGO was treated through mild sonication in aqueous solution, these functionalized rGO sheets were less than two layers, which was determined by atomic force microscopy (AFM) imaging. The water solubility of functionalized rGO after the introduction of polyethyleneimine (PEI) was improved significantly; it was followed by covalent binding of folic acid (FA) molecules to the functionalized rGO to allow us to specifically target CBRH7919 cancer cells by using FA as a receptor. The loading and release behaviors of elsinochrome A (EA) and doxorubicin (DOX) on the functionalized rGO sheets were investigated. The EA loading ratio onto rGO‐C6H4‐CO‐NH‐PEI‐NH‐CO‐FA (abbreviated rGO‐PEI‐FA, the weight ratio of drug loaded onto rGO‐PEI‐FA) was approximately 45.56 %, and that of DOX was approximately 28.62 %. It was interesting that the drug release from rGO‐PEI‐FA was pH‐ and salt‐dependent. The results of cytotoxicity (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) and flow cytometry (FCM) assays, as well as cell morphology observations) clearly showed that the concentration of rGO‐PEI‐FA as the drug‐delivery composite should be less than 12.5 mg L ?1. The conjugation of DOX and rGO‐PEI‐FA can enhance the cancer‐cell apoptosis effectively and can also push the cancer cells to the vulnerable G2 phase of the cell cycle, which is most sensitive and susceptible to damage by drugs or radiation. 相似文献
244.
The present paper studies the effects of precursor amino acids, i.e., L-glutamic acid (Glu), L-glycine (Gly), and L-cysteine (Cys), on the glutathione (GSH) production. The three amino acids were added during the fermentations. The GSH production was analyzed by gas chromatography-mass spectrometry (GC-MS). It was observed that the cell content of Cys reduced continually, Gly maintained a fairly constant concentration, while Glu remained at a high concentration compared with Cys and Gly. The synthesis of GSH was found to significantly increase after 28?h of fermentation upon addition of 6?mmol?l(-1) of each of the three amino acids. Under these conditions, the GSH yields reached 2,250?±?50?mg?l(-1) at 34?h from 1,050?±?50?mg?l(-1) at 28?h. The GC-MS analyses on the effect caused by the addition of amino acids indicated that the addition of Glu was not necessary to improve the GSH production by high-cell-density cultivation of Saccharomyces cerevisiae. The addition of Cys or Gly individually enhances the production of GSH. 相似文献
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Dr. Miaomiao Tong Dr. Fanfei Sun Dr. Gengyu Xing Prof. Chungui Tian Lei Wang Prof. Honggang Fu 《Angewandte Chemie (International ed. in English)》2023,62(52):e202314933
Single atom sites (SAS) often undergo structural recombination in oxygen reduction reaction (ORR), while the effect of valence state and reconstruction on active centers needs to be investigated thoroughly. Herein, the Mn-SAS catalyst with uniform and precise Mn-N4 configuration is rationally designed. We utilize operando synchrotron radiation to track the dynamic evolution of active centers during ORR. Under the applied potential, the structural evolution of Mn-N4 into Mn-N3C and further into Mn-N2C2 configurations is clarified. Simultaneously, the valence states of Mn are increased from +3.0 to +3.8 and then decreased to +3.2. When the potential is removed, the catalyst returned to its initial Mn+3.0-N4 configuration. Such successive evolutions optimize the electronic and geometric structures of active centers as evidenced by theory calculations. The evolved Mn+3.8-N3C and Mn+3.2-N2C2 configurations respectively adjust the O2 adsorption and reduce the energy barrier of rate-determining step. Thus, it can achieve an onset potential of 0.99 V, superior stability over 10,000 cycles, and a high turnover frequency of 1.59 s−1 at 0.85 VRHE. Our present work provides new insights into the construction of well-defined SAS catalysts by regulating the valence states and configurations of active centers. 相似文献
248.
Xing Yali Zhang Mingang Guo Jin Fang Xueyang Hu Xiaoqin Cui Hugang Zhao Miaomiao Yan Minyan 《Journal of Solid State Electrochemistry》2023,27(4):1033-1044
Journal of Solid State Electrochemistry - Lithium-sulfur battery as a new generation of energy storage devices has excellent development potential. In this paper, CeO2/Ce2S3 heterostructure was... 相似文献