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21.
欧洲约有1%~3%的一般人群对铬(Cr)过敏。从人类健康和环境风险的角度来看,评估皮革内潜在的Cr(Ⅲ)和Cr(Ⅵ)释放十分重要。研究考察了皮革体相和表面化学的相关性、Cr(Ⅲ)和Cr(Ⅵ)的释放,以及具有联合释放能力的特定皮革,对释放的铬的还原和络合。采用SEM、EDS、XPS、ATR-FTIR和二苯卡巴肼比色法表征4种皮革。将皮样与人工汗(ASW,pH6.5)和缓冲液(PB,pH 7.5~8.0)接触,采用分光光度法和AAS,对比Cr(Ⅲ)和Cr(Ⅵ)释放效果。具有联合释放能力的特定皮革,在ASW和PB中,能够有效减少Cr(Ⅵ)的含量,其还原能力与革表面及释放的铬的含量相关。采用ATR-FTIR表征不具有该能力且含有较少芳烃基的皮革。结果表明,在革表面和PB溶液中均存在Cr(Ⅵ)。  相似文献   
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The most frequent cause of death by cancer worldwide is lung cancer, and the 5-year survival rate is still very poor for patients with advanced stage. Understanding the crosstalk between the signaling pathways that are involved in disease, especially in metastasis, is crucial to developing new targeted therapies. Toll-like receptors (TLRs) are master regulators of the immune responses, and their dysregulation in lung cancer is linked to immune escape and promotes tumor malignancy by facilitating angiogenesis and proliferation. On the other hand, over-activation of the WNT signaling pathway has been reported in lung cancer and is also associated with tumor metastasis via induction of Epithelial-to-mesenchymal-transition (EMT)-like processes. An interaction between both TLRs and the WNT pathway was discovered recently as it was found that the TLR pathway can be activated by WNT ligands in the tumor microenvironment; however, the implications of such interactions in the context of lung cancer have not been discussed yet. Here, we offer an overview of the interaction of TLR-WNT in the lung and its potential implications and role in the oncogenic process.  相似文献   
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The present study investigates the antioxidant mechanism of grape procyanidins and, in particular, their aptitude to establish redox interactions with two important components of the endogenous antioxidant system of muscle tissues, α-tocopherol (α-TOH) and ascorbic acid (AA). To this end, the progress of lipid oxidation was monitored in fish muscle supplemented with grape procyanidins at the concentrations usually employed in antioxidant food applications, and then related to the redox stability of the endogenous α-TOH and AA. In addition to the lipid oxidation protective effect, the incorporation of procyanidins also provided an improvement of the redox stability of the endogenous components in a straight procyanidinic concentration-dependent manner. Results showed the capacity of procyanidins to repair oxidised α-TOH at medium-long term, and to delay the AA depletion. Therefore, such cooperative redox interaction of exogenous procyanidins adequately complements the natural α-TOH regenerative system supplied by AA that is efficient at the early post mortem stages.  相似文献   
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This paper describes an innovative routing strategy for intelligent transportation units willing to perform merging manoeuvres with a moving convoy. In particular, we consider a transportation unit located inside a city (pursuer unit), and which wishes to join a convoy that is constantly moving around the city. We first describe a solution that considers idealistic conditions, i.e., the traveling time along each street is constant. We then go on to improve our first approach to deal with the realistic random nature of the traveling times experienced by the pursuer and by the convoy leader. Our search strategy applies Dynamic Programming to achieve a meeting point that is optimal in two ways: on one hand, the optimal destination is the one closest to the current pursuer??s position; on the other hand, the optimal meeting point must minimize the time that elapses until the pursuer meets the convoy (considering that the pursuer must always arrive first). Calculating the optimal path to every possible destination is highly inefficient, error prone and time consuming. On the contrary, we propose an efficient search strategy that will achieve the meeting point and the path to it, both optimally and in a very short time. This enables the real-time application of our approach either for finding new solutions or for re-planning old ones owing to unexpected real-conditions.  相似文献   
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This paper gives the theoretical setup so that an ecological model, as a particular mathematical model, can be considered a text written in a formal language (mathematics), and therefore, statistical linguistic laws can be applied to obtain information parameters in different semantic levels of the same model. The statistical laws will be useful to: a) compare semantic levels, submodels, and different models mutually; b) prove that information temperature parameter is an indirect measure of meaning: the significance or semantic component of information, opposed to significant, or comprehension, on the part of the observer (modeller) of the model text. We will apply these ideas in two practical examples.  相似文献   
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Motion camouflage is an animal stealth behaviour in which a shadower—or predator—moves in the vicinity of a shadowee—or prey—in such a way that the later perceives no apparent motion apart from the self motion. Despite some light has been shed on the control mechanism generating this pursuit strategy, it is not fully understood. Motion camouflage represents an interesting challenge in biological motion, and although simulated controllers can be found in the literature, no implementation on real robots has been done so far. This paper presents the first implementation of motion camouflage in real wheeled robots through a polynomial NARMAX model controller. The trajectories to adjust the model are generated using a heuristic approach. The NARMAX model outperforms the heuristic approach in terms of computational time and generates good camouflage trajectories in real robots and simulation. The transparency of polynomial models can also shed some light over this complex animal behaviour.  相似文献   
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