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排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
Kavitej Samra Mathun Kuganesan William Smith Anna Kleyman Robert Tidswell Nishkantha Arulkumaran Mervyn Singer Alex Dyson 《International journal of molecular sciences》2021,22(6)
Metabolically active gasotransmitters (nitric oxide, carbon monoxide and hydrogen sulfide) are important signalling molecules that show therapeutic utility in oxidative pathologies. The reduced form of selenium, hydrogen selenide (HSe−/H2Se), shares some characteristics with these molecules. The simple selenide salt, sodium hydroselenide (NaHSe) showed significant metabolic activity, dose-dependently decreasing ex vivo O2 consumption (rat soleus muscle, liver) and transiently inhibiting mitochondrial cytochrome C oxidase (liver, heart). Pharmacological manipulation of selenoprotein expression in HepG2 human hepatocytes revealed that the oxidation status of selenium impacts on protein expression; reduced selenide (NaHSe) increased, whereas (oxidized) sodium selenite decreased the abundance of two ubiquitous selenoproteins. An inhibitor of endogenous sulfide production (DL-propargylglycine; PAG) also reduced selenoprotein expression; this was reversed by exogenous NaHSe, but not sodium hydrosulfide (NaHS). NaHSe also conferred cytoprotection against an oxidative challenge (H2O2), and this was associated with an increase in mitochondrial membrane potential. Anesthetized Wistar rats receiving intravenous NaHSe exhibited significant bradycardia, metabolic acidosis and hyperlactataemia. In summary, NaHSe modulates metabolism by inhibition of cytochrome C oxidase. Modification of selenoprotein expression revealed the importance of oxidation status of selenium therapies, with implications for current clinical practice. The utility of NaHSe as a research tool and putative therapeutic is discussed. 相似文献
2.
为研究在常温(21±1)℃条件下不同搅拌方式对于厌氧氨氧化污泥复壮及运行影响,采用3组反应器(R1、R2、R3)搅拌方式分别为连续搅拌、间歇搅拌、间歇搅拌方式(R2、R3转速不同),对系统复壮及运行过程的脱氮性能、颗粒污泥性能等进行分析.结果表明,R1、R2、R3分别用10,2,2 d的时间氨氮、亚硝酸盐氮去除率接近100%,R2、R3的厌氧氨氧化速率更高,更适合厌氧氨氧化菌生长;周期实验结果可知,间歇搅拌方式形成的水流流化状态较弱,使反应器呈较低溶解氧的时间较长,更易抑制AOB活性,从而提高厌氧氨氧化菌活性;R1系统提供剪切力大,且持续与基质溶液接触,产生EPS多,稳定运行时期末,R1、R2、R3的颗粒污泥平均粒径为723,675,649μm. 相似文献
3.
将冷轧Ti/Al层状复合材料在675~750 ℃下进行不同时间的退火处理,退火过程中钛和铝都保持过剩,研究了Ti/Al层状复合材料的界面微观组织演变。结果表明:Ti和Al的界面层由2个亚层组成,其中一个为紧密的TiAl3亚层,其微观结构为紧密的TiAl3层,其中分布着随机取向的充满Al的裂纹,另一个为颗粒状的TiAl3亚层,其微观组织结构是颗粒状的TiAl3分布在Al基体中。在不同的退火温度和时间条件下,紧密TiAl3亚层的厚度几乎没有变化,但是颗粒状亚层的厚度随着退火温度及时间的增加而增加;另外,界面层中的TiAl3颗粒的体积分数在不同的温度下均随着退火时间的延长而下降。因此提出了反应扩散模型来描述界面层的形成机理,在此模型中,TiAl3相是化学反应和扩散的结果,并且也考虑了TiAl3相的溶解。计算结果表明TiAl3相的形成与生长由化学反应控制,其等效厚度与退火时间之间遵循线性规律,这主要是因为Ti和Al原子能够快速地通过紧密的薄TiAl3亚层。 相似文献
4.
Ming Zhang Xuefeng Jiang Qicheng Zhang Tao Zheng Mohsen Mohammadniaei Wentao Wang Jian Shen Yi Sun 《Advanced functional materials》2021,31(38):2102274
Immunotherapy is an efficient approach to clinical oncology. However, the immune privilege of the central nervous system (CNS) limits the application of immunotherapeutic strategies for brain cancers, especially glioblastoma (GBM). Tumor resistance to immune checkpoint inhibitors is a further challenge in immunotherapies. To overcome the immunological tolerance of brain tumors, a novel multifunctional nanoparticle (NP) for highly efficient synergetic immunotherapy is reported. The NP contains an anti-PDL1 antibody (aPDL1), upconverting NPs, and the photosensitizer 5-ALA; the surface of the NP is conjugated with the B1R kinin ligand to facilitate transport across the blood-tumor-barrier. Upon irradiation with a 980 nm laser, 5-ALA is transformed into protoporphyrin IX, generating reactive oxygen species. Photodynamic therapy (PDT) further promotes intratumoral infiltration of cytotoxic T lymphocytes and sensitizes tumors to PDL1 blockade therapy. It is demonstrated that combining PDT and aPDL1 can effectively suppress GBM growth in mouse models. The proposed NPs provide a novel and effective strategy for boosting anti-GBM photoimmunotherapy. 相似文献
5.
6.
为了探讨远志多糖的体内、外活性,采用力竭运动动物模型,给予受试动物低、中、高剂量(0.10、0.20、0.40 mg/g·d)远志多糖后,分别测定各组动物负重游泳时间、肝糖原、肌糖原、乳酸、尿素氮含量及乳酸脱氢酶的活力和体外抗氧化活性。结果表明,与空白对照组相较,低、中、高剂量的远志多糖分别延长小鼠的负重游泳时间96.6 s (P<0.05)、254.4 s (P<0.01)和421.8 s (P<0.01),肝糖原含量分别提高13.1%(P<0.05)、37.4%(P<0.01)和56.4%(P<0.01),肌糖原含量分别提高10.8%(P<0.05)、31.2%(P<0.01)和42.0%(P<0.01),运动后乳酸含量分别下降4.6%(P<0.05)、8.6%(P<0.01)和14.5%(P<0.01),尿素氮含量分别降低1.5%(P<0.05)、3.9%(P<0.01)和7.5%(P<0.01),乳酸脱氢酶活力分别提高10.4%(P<0.01)、14.0%(P<0.01)和19.9%(P<0.01)。当远志多糖浓度为4 mg/mL时,对羟基自由基清除率和DPPH自由基的清除率分别为61.3%和79.5%,表明远志多糖有助于缓解机体疲劳,且体外抗氧化性较好。 相似文献
7.
Atharva Kale Natasha M. Rogers Kedar Ghimire 《International journal of molecular sciences》2021,22(8)
Recent advances provide evidence that the cellular signalling pathway comprising the ligand-receptor duo of thrombospondin-1 (TSP1) and CD47 is involved in mediating a range of diseases affecting renal, vascular, and metabolic function, as well as cancer. In several instances, research has barely progressed past pre-clinical animal models of disease and early phase 1 clinical trials, while for cancers, anti-CD47 therapy has emerged from phase 2 clinical trials in humans as a crucial adjuvant therapeutic agent. This has important implications for interventions that seek to capitalize on targeting this pathway in diseases where TSP1 and/or CD47 play a role. Despite substantial progress made in our understanding of this pathway in malignant and cardiovascular disease, knowledge and translational gaps remain regarding the role of this pathway in kidney and metabolic diseases, limiting identification of putative drug targets and development of effective treatments. This review considers recent advances reported in the field of TSP1-CD47 signalling, focusing on several aspects including enzymatic production, receptor function, interacting partners, localization of signalling, matrix-cellular and cell-to-cell cross talk. The potential impact that these newly described mechanisms have on health, with a particular focus on renal and metabolic disease, is also discussed. 相似文献
8.
Yun Liu Mengxue Wang Yin Liang Chen Wang Keiji Naruse Ken Takahashi 《International journal of molecular sciences》2021,22(4)
A thrombus in a coronary artery causes ischemia, which eventually leads to myocardial infarction (MI) if not removed. However, removal generates reactive oxygen species (ROS), which causes ischemia–reperfusion (I/R) injury that damages the tissue and exacerbates the resulting MI. The mechanism of I/R injury is currently extensively understood. However, supplementation of exogenous antioxidants is ineffective against oxidative stress (OS). Enhancing the ability of endogenous antioxidants may be a more effective way to treat OS, and exosomes may play a role as targeted carriers. Exosomes are nanosized vesicles wrapped in biofilms which contain various complex RNAs and proteins. They are important intermediate carriers of intercellular communication and material exchange. In recent years, diagnosis and treatment with exosomes in cardiovascular diseases have gained considerable attention. Herein, we review the new findings of exosomes in the regulation of OS in coronary heart disease, discuss the possibility of exosomes as carriers for the targeted regulation of endogenous ROS generation, and compare the advantages of exosome therapy with those of stem-cell therapy. Finally, we explore several miRNAs found in exosomes against OS. 相似文献
9.
Jiajia Yan Teng Zhang Haizheng Tao Hongbing Zhan Yuanzheng Yue 《Journal of the American Ceramic Society》2021,104(6):2560-2570
We study the structure, crystallization, and performances of the sealing glasses with the composition (mol.%) of 12Al2O3·8B2O3·40SiO2·40RO (R = Mg, Ca, Sr) for solid oxide fuel cells (SOFCs) before and after isothermal treatment at 700°C, which is within the operation temperature range (600-800°C) of SOFCs. The crystallization behavior has been investigated by differential scanning calorimetry and X-ray diffraction under both dynamic and isothermal conditions. The structural evolution is probed using the Raman and nuclear magnetic resonance spectroscopies. The performances of the sealing glasses are characterized in terms of the coefficient of thermal expansion, the crystallization-induced stress at glass–steel interface. We find that strong crystallization occurs at the operation temperature (700°C) far below the crystallization onset temperature measured by DSC. The structure origin of this anomalous crystallization is discussed in terms of structural heterogeneity of the three studied glasses. We determine the residual stress at the interface between the Ca-containing glass and the steel after isothermal treatment at 700°C for 48 h, but this stress does not lead to falling off the glass layer from the steel. This indicates that this glass is a good candidate to be applied in SOFCs. 相似文献
10.
Josephine Eskaf William J. Cleveland Matthias L. Riess 《International journal of molecular sciences》2021,22(9)
Myocardial infarction is a leading cause for morbidity and mortality worldwide. The only viable treatment for the ischemic insult is timely reperfusion, which further exacerbates myocardial injury. Maintaining mitochondrial function is crucial in preserving cardiomyocyte function in ischemia reperfusion (IR) injury. Poloxamer (P) 188 has been shown to improve cardiac IR injury by improving cellular and mitochondrial function. The aim of this study was to show if P188 postconditioning has direct protective effects on mitochondrial function in the heart. Langendorff prepared rat hearts were subjected to IR injury ex-vivo and reperfused for 10 min with 1 mM P188 vs. vehicle. Cardiac mitochondria were isolated with 1 mM P188 vs. 1 mM polyethylene glycol (PEG) vs. vehicle by differential centrifugation. Mitochondrial function was assessed by adenosine triphosphate synthesis, oxygen consumption, and calcium retention capacity. Mitochondrial function decreased significantly after ischemia and showed mild improvement with reperfusion. P188 did not improve mitochondrial function in the ex-vivo heart, and neither further P188 nor PEG induced direct mitochondrial protection after IR injury in this model. 相似文献