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771.
772.
江苏区域旅游游客满意度评价研究 总被引:2,自引:0,他引:2
游客满意是旅游市场竞争力的来源,是稳定规模化游客流的根本动力.运用灰色系统中灰色关联分析法,从交通、旅游景区(点)、购物、环境卫生、住宿、餐饮、娱乐、门票价格、导游讲解服务9个要素入手构建评价指标体系,以江苏12个省辖市为例,对游客满意度进行综合评价,揭示影响游客满意度众多指标之间关系的强弱,对12市游客满意度的优势劣势分析,并进行排序,得出江苏区域旅游游客满意度4个层次:镇江、扬州满意度最高,苏州、常州次之,南京、无锡、徐州、南通为第三层次,泰州、盐城、连云港和淮安最低。 相似文献
773.
774.
Let A be an infinite dimensional stably finite unital simple separable C*-algebra.Let B■A be a stably(centrally)large subalgebra in A such that B is m-almost divisible(m-almost divisible,weakly(m,n)-divisible).Then A is 2(m+1)-almost divisible(weakly m-almost divisible,secondly weakly(m,n)-divisible). 相似文献
775.
Thiamethoxam and its metabolite clothianidin residues pose a potential threat to human health. This study aims to investigate the residue behavior and acute dietary risk assessment of thiamethoxam and clothianidin on spinach. Thiamethoxam and clothianidin were extracted using a quick, easy, cheap, effective, rugged, safe (QuEChERS) method and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At spike levels from 0.01 to 5 mg kg−1, the average recoveries of both analytes were in the range of 94.5–105.5%, with relative standard deviations (RSDs) of 3.8–10.9%. The dissipation behavior of thiamethoxam followed first-order kinetics, with half-lives of ≤1.6 days. Clothianidin appeared readily as a plant metabolite with highest level exhibited during 3 to 5 days after application. Temperature and light may be two main factors for degradation of thiamethoxam. Besides, acute risk assessment of thiamethoxam and clothianidin was evaluated with risk quotients (RQs) <100%, which suggested a low health risk for all consumer groups of Chinese residents. 相似文献
776.
Jinhao Zou Yan Li Xiaojun Su Feng Wang Qingming Li Huiping Xia 《Molecules (Basel, Switzerland)》2022,27(7)
In order to explore the processing and application potential of Chinese yam starch, nine kinds of Chinese yam starch (GY11, GY5, GY2, GXPY, LCY, SFY, MPY, SYPY, ASY) from South China were collected and characterized. The chemical composition, rheological properties, thermal properties, and in vitro starch digestion were compared, and the correlation between the structure and processing properties of these yam starches was analyzed using Pearson correlation. The results show that GY2 had the highest amylose content of 28.70%. All the yam starches were similarly elliptical, and all the yam starch gels showed pseudoplastic behavior. Yam starches showed similar pasting temperatures and resistant starch content, but SYPY showed the largest particle size (28.4 μm), SFY showed the highest setback (2712.33 cp), and LCY showed the highest peak viscosity (6145.67 cp) and breakdown (2672.33 cp). In addition, these yam starches also showed different crystal types (A-type, B-type, C-type), relative crystallinity (26.54–31.48%), the ratios of 1045/1022 cm−1 (0.836–1.213), pasting properties, and rheological properties, so the yam starches have different application potentials. The rheological and pasting properties were related to the structural properties of starch, such as DI, Mw, and particle size, and were also closely related to the thermodynamic properties. The appropriate processing methods and purposes of the processed products of these yam starches can be selected according to their characteristics. 相似文献
777.
Excessive and unresolved neuroinflammation is a key component of the pathological cascade in brain injuries such as ischemic stroke. Tripartite motif-containing 45 (TRIM45) is a ubiquitin E3 ligase involved in various critical biological processes. However, the role of TRIM45 in cerebral ischemia remains unknown. Here, we found that the TRIM45 protein was highly expressed in the peri-infarct areas of mice subjected to cerebral ischemia and reperfusion injury induced by middle cerebral artery occlusion. This study systemically evaluated the putative role of TRIM45 in the regulation of neuroinflammation during ischemic injury and the potential underlying mechanisms. We found that TRIM45 knockdown significantly decreased proinflammatory cytokine and chemokine production in primary cultured microglia challenged with oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Mechanistically, we demonstrated that TRIM45 constitutively interacted with TAB2 and consequently facilitated the Lys-63-linked polyubiquitination of TAB2, leading to the formation of the TAB1–TAK1–TAB2 complex and activation of TAK1, which was ultimately followed by activation of the nuclear factor-kappa B (NF-κB) signaling pathway. In an in vitro coculture Transwell system, downregulation of TRIM45 expression also inhibited the OGD/R-induced activation of microglia and alleviated neuronal apoptosis. More importantly, microglia-specific knockdown of TRIM45 in mice significantly reduced the infarct size, mitigated neurological deficit scores, and improved cognitive function after ischemic stroke. Taken together, our study reveals that the TRIM45–TAB2 axis is a crucial checkpoint that controls NF-κB signaling in microglia during cerebral ischemia and reperfusion injury. Therefore, targeting TRIM45 may be an attractive therapeutic strategy.Subject terms: Cell death in the nervous system, Stroke 相似文献
778.
Fangyuan Li&Daishun Ling Yang Du Zheng Chen Ji Young Lee Peihua Lin Fan Xia Yunan Guan Fangyuan Li Daishun Ling 《中国科学:化学(英文版)》2021,(2):204-217
Theranostic nanosystems that integrate diagnosis and therapy have garnered increasing attention for personalized medicine.The integration of the versatile nanoparticles to fabricate self-assembled theranostic nanomedicines becomes increasingly important in current medical research.Mesoporous silica nanoparticles(MSN)with their highly attractive physicochemical properties and favorable morphological attributes represent ideal templates for the controlled assembly and integration of functional nanomaterials to fabricate self-assembled theranostic nanomedicines.The rationally designed combination strategy and heterostructure will improve the overall bioavailability and preserve the unique property of each nanocomponent.In this review,the cutting-edge strategies for the designed fabrication of MSN-templated self-assembled nanomedicines are summarized.We categorize MSN-based nanomedicines by their unique heterostructures,including core-shell,yolk-shell,core-satellite,heterodimer and core-shell-satellite structures,and discuss the controlled assembly approaches as well as the intriguing applications for disease theranostics.Finally,a perspective on the challenges in the clinical translation of self-assembled theranostic nanomedicines is highlighted. 相似文献
779.
在第75届联合国大会上,我国承诺力争在2030年前实现碳达峰、2060年前实现碳中和。主要由光合作用产生的生物质将在双碳目标中扮演重要角色,通过高效转化可衍生出一系列替代化石产品的高值化学品。其中,2,5-呋喃二甲酸(FDCA)由于具有与石油基对苯二甲酸(TPA)相似的共轭碳环和二酸结构,可替代TPA用于合成热稳定性能、气体阻隔性能更优的生物基呋喃聚酯,大幅降低聚酯行业对化石资源的严重依赖。此外,FDCA在医药、香料、金属配位化学方面也有广泛应用,从而被认为是12种最具潜力的生物基平台化合物之一。FDCA通常可由5-羟甲基糠醛(HMF)通过催化氧化进行合成。相比于需要贵金属催化剂、高温和高压条件、以化学势作为驱动力的传统热催化方法,电催化氧化采用电极电势作为主要驱动力,是更为绿色和高效的新颖合成方法。本综述对电催化氧化制备FDCA反应所用的贵金属、过渡金属和非金属催化剂进行了总结与分析,梳理了催化剂设计和反应机理的研究脉络,并指出了该领域发展所面临的挑战与机遇。 相似文献
780.
以KCl、KBr、KI、KNO3为支持电解质,在pH为1.5~3.0范围内,研究了Zn(Ⅱ)与水溶性的中位-四(4-N-氰乙基吡啶基)卟啉(TγNPNPyP)的反应动力学,利用计算机线性回归拟合,给出了其表观速率常数的一般表达式.研究表明,Zn(Ⅱ)与T γNPNPyP嵌入反应速率顺序为KCl介质>KBr介质>KI介质>KNO3介质,这与Zn(Ⅱ)和Cl-、Br-、I-、NO3-形成配合物的稳定性是一致的,表明平衡阴离子也参与了配位. 相似文献