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71.
Clinical translation of nanoparticles is limited because of their short circulation time, which hampers targeting to prolong therapeutic effects. Angiogenesis is required to regenerate damaged sites under inflammation, and CD11b+ cells turn vasculogenic under hypoxia. As a turning-point strategy to increase the circulation time, this study explores liposomal targeting of splenic CD11b+ cells, which are gathered in the spleen and move to inflamed sites inherently. Moreover, nano-hypoxia is strategized as a therapeutic method by loading liposomes with a hypoxic-mimetic agent (CoCl2) to induce in situ reprogramming of splenic CD11b+ cells upon venous injection. Consequently, the vasculogenic potential of reprogrammed cells accelerates regeneration through inflammation-responsive homing. Hydrophilic coating of liposomes improves the selectivity of splenic targeting in contrast to fast targeting without coating. Hypoxia chambers and surgical induction of splenic hypoxia are compared to validate the reprogramming effect. The strategy is validated in mouse models of inflamed skin, ischemic hindlimbs, and 70% hepatectomy compared with a conventional approach using bone marrow cells. Intravital multiphoton microscopy, 19F 2D/3D MRI, and microchannel hydrogel chips for 3D tissue culture are used as advanced tools. Overall, nanocarrier change to CD11b+ cells prolong targeting by inducing in situ reprogramming for inflammation-responsive vasculogenic therapy.  相似文献   
72.
Ultrasonic peening is a technique to be used for improving the fatigue life of welded structures. The technique makes use of an ultrasonically vibrated pin which is pressed against the toe regions of the weld. The beneficial effect is mainly due to the introduction of favourable compressive stresses on weld toe regions, causing local plastic deformation and reducing stress concentration effect. This paper deals with the influence of ultrasonic peening treatment on fatigue life improvement in butt-welded plates. Fatigue life is predicted for the welded plate as per BS 7608 standard, AWS D 1.1 structural welding code and IIW-XIII-1539-96 standard, and they are compared with the experimental results. The ultrasonic peening technique is applied on a plain carbon steel plate weldment, and specimens conforming to ASTM E 466 standard are prepared and tested in a servohydraulic static dynamic testing machine at three different stress levels. Afterwards their fatigue lives are obtained. The comparison of the fatigue life in unpeened and peened specimens brings out the beneficial influence of the treatment. It is found that the improvement in fatigue life is up to 35% at 250 MPa of applied stress. But at higher stress levels, the benefit is less. At 350 MPa of applied stress, peening results in lower fatigue life. A comparison of the predicted fatigue lives from various standards with the experimental results shows that it is very close to the life at 50% probability of survival as predicted by the BS 7608 standard. The details of the experiments conducted and the results obtained are furnished in this paper.  相似文献   
73.
The potential internal occupational exposure encountered as a consequence of the 232Th-233U fuel cycle are likely to arise predominantly from the inhalation of 232Th, 233U and (232Th + 233U) compounds of absorption Types M and S. In the past, although direct and indirect methods for assessments of internal exposure to 232Th and its daughters were developed, standardised and employed, no such attempts have been made with regard to 233U and 233U + 232Th. Therefore, feasibility studies for assessing internal exposure to 233U have been conducted using three methods: urine bioassay, in vivo counting and measurement of thoron gas in the exhaled breath of a worker. This paper describes details of these studies and discusses the results obtained.  相似文献   
74.
Papillomaviruses are pathogens which induce cutaneous and mucosal lesions in man and in many animal species. The characterization of these viruses was rather low, because viral infection cannot be fully reproduced in cell culture. The development of molecular biology techniques in the 1970s permitted to establish the remarkable plurality of the viruses, the tissue specificity and pecular pathogenicity linked to the type. Studies of the genome organization, the gene expression regulation and the protein characterization gave many informations leading to understand the mechanisms of viral-related carcinogenesis, especially the role of HPV16, the major risk factor for the development of squamous cervical carcinoma.  相似文献   
75.
Journal of Materials Science: Materials in Electronics - Because of their high-efficiency interfacial charge-transfer characteristics of heterojunction nanocomposites have sparked widespread...  相似文献   
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Studies on traffic accidents among underage users of motorcycles are seldom seen in literature. This study was done in Yamunanagar, India where boys as young as 8 years ride motorcycles. It attempts to find out the behavioural and non-behavioural factors leading to motorcycle use and the predisposition to accidents among male school children aged between 10 and 16 years. A questionnaire was used to evaluate those factors among 1760 subjects in 38 schools. Fifteen percent of subjects had had an accident while riding motorcycle. Most of the behavioural and all the non-behavioural factors have a statistically significant influence on accident proneness. Aggressive behaviour and previous encounter with the police are the two strong predictors of accidents (p<0.001). Children as riders are exposed to higher risks of accident and longer life with disability. It also explains how these children behaviourally take up adult roles and seek adult risk taking attitudes. The implications of child motorcycle riders upon children themselves and on the society are discussed for a greater discourse on road safety motorcycle riding policy and to highlight the behavioural and non-behavioural factors that are associated with traffic accidents.  相似文献   
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79.
碳纤维复合材料具有高比强度、高比刚度、耐腐蚀和抗疲劳等优点,是大跨度结构拉索的理想型材料。本文基于电磁层析成像技术采用有限元方法对碳纤维拉索的断股和脱粘缺陷进行仿真研究,设计了一种8线圈圆周型传感器阵列,探究了传感器尺寸、激励电流大小与磁感应强度的关系,根据仿真电磁信号研究了LBP算法、Tikhonov算法和Landweber算法3种重建算法对不同拉索缺陷重建图像质量的影响。结果表明,在研究范围内随着传感器线圈直径的减小和激励电流的增大,磁感应强度逐渐增大,并在线圈直径为5 mm和激励电流为1 A时达到最大值;与其他图像重建方法相比,Tikhonov算法能够更好的平衡图像重建效果和成像质量,更适用于碳纤维拉索缺陷检测图像的重建过程。此外,在传感器阵列固定的情况下将拉索缺陷旋转,分析了不同投影角度对缺陷成像效果的影响。本研究旨在为实验条件下碳纤维拉索的传感器阵列设计和缺陷检测成像提供参考依据。  相似文献   
80.
International Journal of Wireless Information Networks - Data centres have seen significant growth recently as a result of the phenomenal rise of cloud computing. These data centres typically use...  相似文献   
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