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971.
动物群落是构成城市绿地生态系统的关键要素,声景作为野生动物重要的生态信息,掌握其时空变化及其影响因素,对于指导城市绿地景观设计与生物多样性保护具有重要意义。本文以Web of Science数据库的核心合集2005–2022年收录的67篇研究文献为对象,综合梳理与分析了城市绿地动物声景的时空模式及其驱动因素。城市绿地动物声景在空间上表现出环境空间梯度和植被空间结构的差异,动物声音多样性随海拔、纬度、城市化程度的降低以及植被类型和高度的增加呈现升高趋势。时间尺度呈现出昼夜、季节和年度变化差异,表现为鸟类在黎明和黄昏合唱、昆虫和两栖动物在夜间鸣叫以及季节性和年度性发声规律等。影响城市动物声景模式的因素主要包括植被、环境、人为干扰和动物自身驱动等。动物声景作为当前声景生态学研究的热点之一,面临大时空尺度演变规律研究不足、动物声景分析有限等挑战,建议未来着重开展多时空尺度变化规律研究、创新动物声景分析方法、定量解析影响因素及其响应机制、建立全球动物声景数据库等。  相似文献   
972.
1 引言 传统的植物光合生理生态研究中,多用照度计来测定光照指标,它以人眼对光亮度的响应特性为基础,与植物叶片对光照的响应曲线差异很大;而太阳光谱中只有400—700nm的波段才是光合有效辐射  相似文献   
973.
The marine environment can be extremely dangerous, and the harm caused by marine organisms when they contact the human body can be especially harmful, even deadly. Contact includes stings, bites, wounds, and consumption as food. In this article, the characteristics of the common marine biological injuries are summarized, the major marine organisms causing damage in China’s marine waters are described, and injury prevention and treatment methods are discussed.  相似文献   
974.
菰属系统与演化研究—胚形态   总被引:1,自引:1,他引:0  
陈守良  杨光 《植物研究》1993,13(4):346-352
本文采用光学显微镜对全世界菰属4种2亚种及其有关属种共4属7种的胚形态进行系统研究后,获得菰属Zizania L.与山涧草Chikusichloa apuatica Koidz.的胚型为F+FP,稻Oryza sativa L.与拟菰Zizaniopsis miliacea(Michx.)Doell & Aschers.的胚型为F+FP,其中山涧草的胚型为首次报导。根据胚型,这4属均应位在禾本科G  相似文献   
975.
Viburnum luzonicum is widely distributed in China. Its branch extracts showed potential α-amylase and α-glucosidase inhibitory activities. In order to discover new bioactive constituents, five undescribed phenolic glycosides, viburozosides A−E ( 1 – 5 ), were obtained by bioassay-guided isolation coupled with HPLC-QTOF-MS/MS analysis. Their structures were elucidated by spectroscopic analyses, including 1D NMR, 2D NMR, ECD, and ORD. All compounds were tested for their α-amylase and α-glucosidase inhibitory potency. Compound 1 showed significantly competitive inhibition against α-amylase (IC50=17.5 μM) and α-glucosidase (IC50=13.6 μM).  相似文献   
976.
Development of suitable antimicrobial biomaterials for hygienic wound dressing and healing is an important requirement for medical application. Durable mechanical properties increase the application range of biomaterial in different environmental and biological conditions. Due to the inherent brittleness of silk fibroin (SF), polyurethane fiber (PUF) was used to modify SF containing actinomycin X2 (Ac.X2) to prepare silk fibroin@actinomycin X2/polyurethane fiber (ASF/PUF) blend membranes. The ASF/PUF blend membrane was developed by solution casting method. Incorporation of PUF improved the flexibility of material and introduction of Ac.X2 has increased antibacterial activity of materials. Excellent mechanical properties (tensile strength up to 25.7 MPa and elongation at break up to 946.5 %) of 50 % SF+50 % PUF blend membrane were proved by tensile testing machine. FT-IR spectra, TGA, contact angle and DMA were tested to prove the blend membrane's physico-chemical characteristics. ASF/PUF blend membrane displayed satisfactory antibacterial activity against S. aureus, and the cytotoxicity tests showed that the blend membrane has better biosafety compared to directly applied Ac.X2 in soluble form. These results suggest that the modification of SF through PUF for development of flexible antibacterial membranes has great potential application value in the field of silk-like material fabrication.  相似文献   
977.
本试验选用抗菌蛋白产生菌枯草芽孢杆菌(B.subtilis) TG26和晶体蛋白产生菌苏云金芽孢杆菌(B.thuringiesis subsp,pacifeus) AS1.904的营养缺陷型衍生株,在聚乙二醇的诱导下进行原生质体种间融合,获得了表现双亲遗传性状的种间融合菌株。融合率为7.52×10~6,融合子经传代10次,稳定率为19.5%。融合菌株的菌落和细胞形态与亲本株明显不同。通过SDS-聚丙烯酰胺凝胶电泳检测,融合菌株表达了亲本的抗菌蛋白和毒素蛋白。抑菌杀虫试验表明,融合重组菌株具有抑制多种植物病原菌和毒杀鳞翅目幼虫的能力。  相似文献   
978.
To develop new highly effective anticancer agents derived from naturally occurring stilbene scaffold, in total of 24 indole and indazole-based stilbenes including 17 new compounds were designed according to molecular hybridization strategy and synthesized via Witting reaction. The cytotoxic screening results against human tumor cell lines (K562 cells and MDA-MB-231 cells) showed that indole and indazole-based stilbenes are of great interest for developing anticancer agents as eight derivatives possessed strong antiproliferative activities with IC50 values less than 10 μM, and those synthetic derivatives displayed more higher cytotoxicities against K562 cells than MDA-MB-231 cells. In particular, indole-based stilbene bearing piperidine exhibited the most potent cytotoxicities against both K562 and MDA-MB-231 cells with IC50 values 2.4 μM and 2.18 μM, respectively, along with a remarkable selectivity towards human normal L-02 cells. Together, the results suggested that indole and indazole-based stilbenes are promising anticancer scaffolds worthy of further investigation.  相似文献   
979.
As a distinctive member of the noncoding RNA family, circular RNAs (circRNAs) are generated from single-stranded, covalently closed structures and are ubiquitous in mammalian cells and tissues. Due to its atypical circular architecture, it was conventionally deemed insignificant dark matter for a prolonged duration. Nevertheless, studies conducted over the last decade have demonstrated that this abundant, structurally stable and tissue-specific RNA has been increasingly relevant in diverse diseases, including cancer, neurological disorders, diabetes mellitus and cardiovascular diseases (CVDs). Therefore, regulatory pathways controlled by circRNAs are widely involved in the occurrence and pathological processes of CVDs through their function as miRNA sponges, protein sponges and protein scaffolds. To better understand the role of circRNAs and their complex regulatory networks in CVDs, we summarize current knowledge of their biogenesis and function and the latest research on circRNAs in CVDs, with the hope of paving the way for the identification of promising biomarkers and therapeutic strategies for CVDs.  相似文献   
980.
Hepatocellular carcinoma (HCC) is one of the most common malignant tumours worldwide. Given metabolic reprogramming in tumours was a crucial hallmark, several studies have demonstrated its value in the diagnostics and surveillance of malignant tumours. The present study aimed to identify a cluster of metabolism-related genes to construct a prediction model for the prognosis of HCC. Multiple cohorts of HCC cases (466 cases) from public datasets were included in the present analysis. (GEO cohort) After identifying a list of metabolism-related genes associated with prognosis, a risk score based on metabolism-related genes was formulated via the LASSO-Cox and LASSO-pcvl algorithms. According to the risk score, patients were stratified into low- and high-risk groups, and further analysis and validation were accordingly conducted. The results revealed that high-risk patients had a significantly worse 5-year overall survival (OS) than low-risk patients in the GEO cohort. (30.0% vs. 57.8%; hazard ratio [HR], 0.411; 95% confidence interval [95% CI], 0.302–0.651; p < 0.001) This observation was confirmed in the external TCGA-LIHC cohort. (34.5% vs. 54.4%; HR 0.452; 95% CI, 0.299–0.681; p < 0.001) To promote the predictive ability of the model, risk score, age, gender and tumour stage were integrated into a nomogram. According to the results of receiver operating characteristic curves and decision curves analysis, the nomogram score possessed a superior predictive ability than conventional factors, which indicate that the risk score combined with clinicopathological features was able to achieve a robust prediction for OS and improve the individualized clinical decision making of HCC patients. In conclusion, the metabolic genes related to OS were identified and developed a metabolism-based predictive model for HCC. Through a series of bioinformatics and statistical analyses, the predictive ability of the model was approved.  相似文献   
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