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181.
曹子旭  马明 《中国园林》2023,39(3):72-77
立足于“十四五”全面推进乡村振兴的时代背景,聚焦内蒙古典型草原区传统村落景观,以文化地理学“景观-基因”理论为基础,基于内蒙古典型草原区传统村落景观具有人工营建与草原环境相协调的核心价值,提出了“时间-空间-文化”三维耦合的景观基因识别、提取方法,解译出“逐水草居、农牧结合、聚散有致、内生植入、崇尚自然、天人合一、共融开放、热情豪迈”八大景观基因。从景观空间格局、景观过程、景观感知3个维度总结出内蒙古典型草原区传统村落的景观特征:景观空间格局的地域系统性、景观过程的历史演化性、景观感知的民族融合性。拓展了内蒙古典型草原区传统村落景观类型辨析和传承保护的理论视野,为内蒙古人居环境的可持续发展和乡村振兴提供科学的方法指导。  相似文献   
182.
中国世界自然遗产及缓冲区普遍存在大量社区居 民,如何科学选择居民点发展模式是遗产保护管理中需重点关 注的问题。以云岭片区为例,首先通过对社区历史风貌、人口 结构与产业发展模式等进行田野调查,利用指标体系法从自然 条件、区位条件、人口结构、产业发展模式、景观风貌与传统 文化五方面对云岭片区居民点居住适宜性进行评估。其次,利 用物种分布模型研究居民点对滇金丝猴栖息地的影响,得到基 于遗产地核心价值保护的居民点分类结果。对以上研究结果进 行叠加分析,最终将片区内各居民点分为搬迁型、疏解型、传 统生活生产控制型和生态旅游控制型4种发展模式。研究成果 将为以标准x入选的世界自然遗产地居民点发展模式的探讨提 供技术指导和案例参照。  相似文献   
183.
目前国内对海绵生境生物多样性方面的研究还较为欠缺,有蓄水功能的塘类海绵生境可作为鸟类觅食及栖息之地。为了探究塘类海绵生境的鸟类特征,以及生境中的设计与环境因子是如何影响鸟类群落多样性特征的,对重庆悦来会展城的干塘与湿塘进行调查,采集生境中的鸟类、植被、面积特征与环境干扰特征数据。采用聚类分析的方法明确鸟类群落组成特征,通过构建结构方程模型,探究塘类海绵生境特征因子对鸟类群落多样性特征的影响。经过四季监测实地调研,总共观测到64种鸟类,可划分为4种鸟类集团,整体鸟类群落多样性特征受到生境面积、蓄水层面积、乔木多样性、灌木多样性、乔木胸径、乔木盖度、噪声、距林地距离和距非绿地建设用地距离的显著影响。通过合理的设计策略可以提升塘类海绵生境鸟类多样性特征。本研究对于探索城市绿地小微生境的生物多样性效益,促进海绵城市精细化营建具有重要价值。  相似文献   
184.
Cold Atmospheric Plasma (CAP) is an emerging technology with great potential for biomedical applications such as sterilizing equipment and antitumor strategies. CAP has also been shown to improve skin wound healing in vivo, but the biological mechanisms involved are not well known. Our study assessed a possible effect of a direct helium jet CAP treatment on keratinocytes, in both the immortalized N/TERT-1 human cell line and primary keratinocytes obtained from human skin samples. The cells were covered with 200 µL of phosphate buffered saline and exposed to the helium plasma jet for 10–120 s. In our experimental conditions, micromolar concentrations of hydrogen peroxide, nitrite and nitrate were produced. We showed that long-time CAP treatments (≥60 s) were cytotoxic, reduced keratinocyte migration, upregulated the expression of heat shock protein 27 (HSP27) and induced oxidative cell stress. In contrast, short-term CAP treatments (<60 s) were not cytotoxic, did not affect keratinocyte proliferation and differentiation, and did not induce any changes in mitochondria, but they did accelerate wound closure in vitro by improving keratinocyte migration. In conclusion, these results suggest that helium-based CAP treatments improve wound healing by stimulating keratinocyte migration. The study confirms that CAP could be a novel therapeutic method to treat recalcitrant wounds.  相似文献   
185.
Essential changes in cell metabolism and redox signaling occur during the reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). In this paper, using genetic and pharmacological approaches, we have investigated the role of electron transport chain (ETC) complex-I (CI) of mitochondria in the process of cell reprogramming to pluripotency. Knockdown of NADH-ubiquinone oxidoreductase core subunits S1 (Ndufs1) or subunit B10 (Ndufb10) of the CI or inhibition of this complex with rotenone during mouse embryonic fibroblast (MEF) reprogramming resulted in a significantly decreased number of induced pluripotent stem cells (iPSCs). We have found that mitochondria and ROS levels due course of the reprogramming tightly correlate with each other, both reaching peak by day 3 and significantly declining by day 10 of the process. The transient augmentation of mitochondrial reactive oxygen species (ROS) could be attenuated by antioxidant treatment, which ameliorated overall reprogramming. However, ROS scavenging after day 3 or during the entire course of reprogramming was suppressive for iPSC formation. The ROS scavenging within the CI-deficient iPSC-precursors did not improve, but further suppressed the reprogramming. Our data therefore point to distinct modes of mitochondrial ROS action during the early versus mid and late stages of reprogramming. The data further substantiate the paradigm that balanced levels of oxidative phosphorylation have to be maintained on the route to pluripotency.  相似文献   
186.
Ancient lakes are known speciation hotspots. One of the most speciose groups in the ancient Lake Baikal are gammaroid amphipods (Crustacea: Amphipoda: Gammaroidea). There are over 350 morphological species and subspecies of amphipods in Baikal, but the extent of cryptic variation is still unclear. One of the most common species in the littoral zone of the lake, Eulimnogammarus verrucosus (Gerstfeldt, 1858), was recently found to comprise at least three (pseudo)cryptic species based on molecular data. Here, we further explored these species by analyzing their mitogenome-based phylogeny, genome sizes with flow cytometry, and their reproductive compatibility. We found divergent times of millions of years and different genome sizes in the three species (6.1, 6.9 and 8 pg), further confirming their genetic separation. Experimental crossing of the western and southern species, which are morphologically indistinguishable and have adjacent ranges, showed their separation with a post-zygotic reproductive barrier, as hybrid embryos stopped developing roughly at the onset of gastrulation. Thus, the previously applied barcoding approach effectively indicated the separate biological species within E. verrucosus. These results provide new data for investigating genome evolution and highlight the need for precise tracking of the sample origin in any studies in this morphospecies.  相似文献   
187.
188.
As a commercial high-grade cut flower, the marketability of herbaceous peony (Paeonia lactiflora Pall.) is limited by its short vase life in water. Si (silicon) is an alternative to improve the postharvest life of cut flowers. However, the effects of the combined application of Si and preservatives on the postharvest performance of cut peony flowers are unknown. In this study, the effects of a Si application and a preservative alone and collegial on the longevity of the vase life, water loss, antioxidant defense system, and stock carbohydrates level of cut flowers of three peony cultivars were investigated. It was observed that Si effectively prolonged the vase life, while the preservative alone, to a lesser extent, but markedly induced an early flowering and a greater flower diameter (flower open degree). The simultaneous use of Si and the preservatives not only showed larger flowers, but also improved the postharvest performance as characterized by an extended vase life and delayed the water loss. In addition, the Si supplementation dramatically intensified the antioxidant defense system (ameliorated antioxidant enzymes and alleviated ROS accumulation) in petals but did not increase the stock carbohydrates (starch and soluble sugars) levels, as compared to the treatment with the preservative alone. We show that a Si supplementation to a preservative is highly recommended for a large-scale use to promote the postharvest performance and competitiveness of marketed cut flowers.  相似文献   
189.
Ovarian cancer recurrence is frequent and associated with chemoresistance, leading to extremely poor prognosis. Herein, we explored the potential anti-cancer effect of a series of highly charged Ru(II)-polypyridyl complexes as photosensitizers in photodynamic therapy (PDT), which were able to efficiently sensitize the formation of singlet oxygen upon irradiation (Ru12+ and Ru22+) and to produce reactive oxygen species (ROS) in their corresponding dinuclear metal complexes with the Fenton active Cu(II) ion/s ([CuRu1]4+ and [Cu2Ru2]6+). Their cytotoxic and anti-tumor effects were evaluated on human ovarian cancer A2780 cells both in the absence or presence of photoirradiation, respectively. All the compounds tested were well tolerated under dark conditions, whereas they switched to exert anti-tumor activity following photoirradiation. The specific effect was mediated by the onset of programed cell death, but only in the case of Ru12+ and Ru22+ was preceded by the loss of mitochondrial membrane potential soon after photoactivation and ROS production, thus supporting the occurrence of apoptosis via type II photochemical reactions. Thus, Ru(II)-polypyridyl-based photosensitizers represent challenging tools to be further investigated in the identification of new therapeutic approaches to overcome the innate chemoresistance to platinum derivatives of some ovarian epithelial cancers and to find innovative drugs for recurrent ovarian cancer.  相似文献   
190.
如何将计算任务分配到合适的边缘计算资源上进行计算,以满足边缘计算环境下用户的计算需求、提高用户任务请求 的服务质量,是边缘计算中面临的关键问题。 本文提出一种基于人工鱼群搜索的边缘计算任务调度方法(AFETSA)。 将人工 鱼群搜索算法和边缘计算任务调度模型相结合,采用非线性递减函数动态地调整人工鱼的视野范围和步长,以提高启发式任务 调度算法的全局搜索能力,降低任务的计算时延;同时与禁忌搜索算法进行融合,通过引入忌禁表,在每一次迭代中防止算法陷 入局部最优,提高算法的寻优能力。 CloudSim3. 0 仿真平台实验评测结表明,本文所提 AFETSA 方法和已有的 AFSA、ACO 和 PSO 这 3 种调度算法相比,在任务执行时间、算法稳定性、负载均衡方面都有明显的提升,可充分利用边缘服务器计算资源,提 升计算任务的计算性能,有效解决边缘计算中任务调度不均导致的时延过高和负载不均衡问题。  相似文献   
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