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11.
The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti3C2, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti3C2 nanosheets. In constructing these heterojunctions, Ti3C2 nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti3C2 composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti3C2 composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti3C2 Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti3C2 composition with 30 wt.% of Ti3C2, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti3C2 as a low-cost co-catalyst.  相似文献   
12.
To analyze the causes and mechanisms affecting the fracture toughness of X80 pipeline steel welded joints against H2S, the fracture toughness of different zones of X80 pipeline steel welded joints in both air and saturated H2S solution was investigated. The fracture toughness of welded joints degraded significantly in the saturated H2S solution, where the crack tip opening displacement (CTOD) characteristic value in the coarse grain heat-affected zone (CGHAZ) and weld metal (WM) was only 8% and 12% of that in air, respectively. However, the sub-critical grain heat-affected zone (SCHAZ) showed better resistance to H2S corrosion, with the CTOD characteristic value reaching 42% of that in air. The resistance of the welded joint to H2S corrosion was sensitive to microstructures. The grain boundary ferrite (GBF) presented in WM, and the angle of grain boundary orientation in CGHAZ was not conducive to hindering crack propagation. Moreover, the formation of the resultant hydrogen cracks owing to the H2S corrosion also reduced the fracture toughness of the welded joint.  相似文献   
13.
Photocatalytic water splitting has garnered tremendous attention for its capability to produce clean and renewable H2 fuel from inexhaustible solar energy. Until now, most research has focused on scarce pure water as the source of H2, which is not consistent with the concept of sustainable energy. Hence, the importance of photocatalytic splitting of abundant seawater in alleviating the issue of pure water shortages. However, seawater contains a wide variety of ionic components which have unknown effects on photocatalytic H2 production. This work investigates photocatalytic seawater splitting conditions using environmentally friendly amorphous carbon nitride (ACN) as the photocatalyst. The individual effects of catalyst loading (X1), sacrificial reagent concentration (X2), salinity (X3), and their interactive effects were studied via the Box–Behnken design in response surface modeling towards the H2 evolution reaction (HER) from photocatalytic artificial seawater splitting. A second-order polynomial regression model is predicted from experimental data where the variance analysis of the regressions shows that the linear term (X1, X2), the two-way interaction term X1X2, and all the quadratic terms (X12, X22, X23) pose significant effects towards the response of the HER rate. Numerical optimization suggests that the highest HER rate is 7.16 µmol/h, achievable by dosing 2.55 g/L of ACN in 45.06 g sea salt/L aqueous solution containing 17.46 vol% of triethanolamine. Based on the outcome of our findings, an apparent effect of salt ions on the adsorption behavior of the photocatalyst in seawater splitting with a sacrificial reagent has been postulated.  相似文献   
14.
Omeprazole (Prilosec®) is a selective and irreversible proton pump inhibitor used to treat various medical conditions related to the production of excess stomach acids. It functions by suppressing secretion of those acids. Radiolabeled compounds are commonly employed in the drug discovery and development process to support efforts including library screening, target identification, receptor binding, assay development and validation and safety assessment. Herein, we describe synthetic approaches to the controlled and selective labeling of omeprazole with tritium via hydrogen isotope exchange chemistry. The chemistry may also be used to prepare tritium labeled esomeprazole (Nexium®), the active pure (S)‐enantiomer of omeprazole.  相似文献   
15.
Although graphitic carbon nitride nanosheets (CNs) with atomic thickness are considered as promising materials for hydrogen production, the wide band gap (3.06 eV) and rapid recombination of the photogenerated electron–hole pairs impede their applications. To address the above challenges, we synergized atomically thin CNs and graphene quantum dots (GQDs), which were fabricated as 2D/0D Van der Waals heterojunctions, for H2 generation in this study. The experimental characterizations indicated that the addition of GQDs to the π-conjugated system of CNs can expand the visible light absorption band. Additionally, the surface photovoltage spectroscopy (SPV) confirmed that introducing GQDs into CNs can facilitate the transport of photoinduced carriers in the melon chain, thus suppressing the recombination of charge carriers in body. As a result, the H2 production activity of the Van der Waals heterojunctions was 9.62 times higher than CNs. This study provides an effective strategy for designing metal-free Van der Waals hetero-structured photocatalysts with high photocatalytic activity.  相似文献   
16.
刘珊  韩艳秋 《现代肿瘤医学》2016,(18):2842-2845
目的:探讨维生素C 是否能影响顺铂杀伤卵巢癌细胞株OVCAR5、SKOV3、CAOV3,并对其作用机制进行初探。方法:使用梯度浓度维生素C及顺铂处理卵巢癌细胞株,显微镜下观测细胞的形态学变化;使用ATP-TCA方法检测细胞生长抑制情况。选择对维生素C敏感的卵巢癌细胞株。氧化敏感探针DCFH-DA标记细胞 ,检测不同浓度维生素C处理不同时间后细胞内过氧化氢(H2O2 )水平。结果:三株卵巢癌细胞维生素C处理的敏感度不同,但总体呈现出随着维生素C浓度的增加,细胞受到抑制作用增加,维生素C对于顺铂杀伤细胞的作用具有辅助加强效应,该作用呈现剂量依赖效应。其中较低浓度维生素C处理OVCAR5细胞15min各组胞内H2O2 水平相比对照组稍高,当处理浓度为5 000μmol/L时细胞H2O2 水平明显升高,达到164%。培养30min后,荧光强度显示细胞内H2O2 水平比15min时升高更明显。不同浓度组分别达到对照组的94%、106%、122%、188%,培养60min后检测荧光强度发现各给药组H2O2 水平均已低于对照组。12h后检测到细胞内的H2O2 水平处于更低水平,各组均未达到对照组的50%。结论:较高浓度维生素C能增强顺铂杀伤卵巢癌细胞株的能力,并呈现一定的剂量依赖性。该结果可能由于维生素 C通过自氧化机制产生过氧化氢促进卵巢癌细胞凋亡。  相似文献   
17.
通过接枝率、接触角、透水时间、拉伸应力应变、ESCA的测定以及不冲击实验研究了在DCP和BP等存在下电晕放电引发含氢硅油接枝PET织物及其拒水性能,实验结果表明:电晕放电能有效引发含氢硅油在PET织物表面的接枝共聚反应,随电晕放电处理时间的延长,PET织物表面接枝率增大;接枝后PET织物拒水效果明显增强;电晕放电引发接枝改性后PET织物无损伤,力学性能基本保持不变。  相似文献   
18.
目的]已有研究表明H2S可拮抗心肌纤维化,但线粒体靶向性H2S能否拮抗心肌梗死后心肌纤维化,且是否与调控线粒体融合与分裂有关目前并不明确。为了探究这一关系,进行了该研究。 [方法]在动物实验中予以异丙肾上腺素[ISO,50 mg/(kg·d)]腹腔注射构建SD大鼠心肌梗死模型,对各组大鼠行心电图检测,使用线粒体H2S供体AP39[36 μg/(kg·d)],腹腔注射连续处理SD大鼠4周,使用Masson染色检测心肌纤维化情况,使用Western blot检测相关蛋白表达情况。体外实验以氯化钴(CoCl2,800 μmol/L)诱导H9c2心肌细胞缺氧损伤,AP39(100 nmol/L)处理H9c2细胞,使用DL-炔丙基甘氨酸(PAG,2 mmol/L)抑制内源性硫化氢合成酶胱硫醚-γ-裂解酶(CSE),并通过荧光探针检测心肌细胞活性氧(ROS)的水平。 [结果]梗死大鼠心肌存在明显间质纤维化,胶原纤维大量堆积,且CSE、线粒体融合蛋白2(MFN2)表达下调,线粒体动力相关蛋白1(DRP1)表达增加,AP39干预后则可明显改善以上变化,而加入CSE抑制剂PAG则可逆转AP39的以上作用。同时在体外实验中发现,以CoCl2诱导H9c2心肌细胞缺氧损伤时,细胞内ROS水平升高,MFN2表达下调,DRP1表达增加,AP39则可上调MFN2蛋白表达,抑制DRP1表达,降低心肌细胞ROS水平,而PAG则可逆转以上变化。 [结论]线粒体靶向性H2S供体AP39可以改善心肌梗死大鼠心肌纤维化,且可促进线粒体融合,抑制线粒体过度分裂。  相似文献   
19.
目的 研究氢气(H2)对于防治氧中毒急性肺损伤(HALI)的作用机制.方法 将30只雄性Sprague-Dawley大鼠随机分为3组:正常对照组、氧中毒模型组(HALI组)和H2治疗组(H2组).其中正常对照组大鼠仅暴露于常压空气,HALI组和H2组大鼠暴露于100%医用纯氧,每隔12 h分别腹腔注射医用生理盐水和氢饱和生理盐水(10 ml/kg).60 h后对各组大鼠进行动脉血氧分压检测和肺组织病理学检查,并应用RT-qPCR和Western印迹技术检测肺组织中血红素加氧酶1(human heme oxygenase 1,HO-1)的mRNA转录水平和蛋白表达水平.结果与HALI组相比,H2组大鼠因慢性纯氧暴露导致的肺损伤程度明显减轻,动脉血氧饱和度升高,HO-1蛋白及其mRNA在肺组织中的表达显著升高.结论 HO-1可能在H2防治大鼠HALI中发挥重要作用.  相似文献   
20.
Subarachnoid hemorrhage (SAH) is a common acute and severe disease worldwide, which imposes a heavy burden on families and society. However, the current therapeutic strategies for SAH are unsatisfactory. Hydrogen sulfide (H2S), as the third gas signaling molecule after carbon monoxide and nitric oxide, has been widely studied recently. There is growing evidence that H2S has a promising future in the treatment of central nervous system diseases. In this review, we focus on the effects of H2S in experimental SAH and elucidate the underlying mechanisms. We demonstrate that H2S has neuroprotective effects and significantly reduces secondary damage caused by SAH via antioxidant, antiinflammatory, and antiapoptosis mechanisms, and by alleviating cerebral edema and vasospasm. Based on these findings, we believe that H2S has great potential in the treatment of SAH and warrants further study to promote its early clinical application.  相似文献   
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