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71.
Measurement of flow speed in the channels of novel threadlike structures on the surfaces of mammalian organs 总被引:1,自引:0,他引:1
There have been several reports on novel threadlike structures (NTSs) on the surfaces of the internal organs of rats and rabbits
since their first observation by Bonghan Kim in 1963. To confirm this novel circulatory function, it is necessary to observe
the flow of liquid through the NTS as well as the structurally corroborating channels in the NTS. In this article, we report
on the measurement of the flow speed of Alcian blue solution in the NTSs on the organ surfaces of rabbits, and we present
electron microscopic images depicting the cribrous cross-section with channels. The speed was measured as 0.3 ± 0.1 mm/s,
and the flow distance was up to 12 cm. The flow was unidirectional, and the phase contrast microscopic images showed that
the NTSs were strongly stained with Alcian blue. The ultrastructure of the NTSs revealed by cryo-scanning electron microscopy
and high-voltage electron microscopy showed that (1) there were cell-like bodies and globular clumps of matter inside the
sinus of the channel with thin strands of segregated zones which is a microscopic evidence of the liquid flow, (2) the sinuses
have wall structures surrounded with extracellular matrices of collagenous fibers, and (3) there exists a cribriform structure
of sinuses. To understand the mechanism for the circulation, a quantitative analysis of the flow speed has been undertaken
applying a simplified windkessel model. In this analysis, it was shown that the liquid flow through the NTSs could be due
to peristaltic motion of the NTS itself.
Baeckkyoung Sung and Min Su Kim contributed equally to this work. 相似文献
72.
上海市PM2.5的物理化学特征及其生物活性研究 总被引:3,自引:1,他引:2
采集了上海市区和郊区春季和夏季的大气PM2.5样品,分析了市区和郊区春夏2季PM2.5质量浓度变化的规律,使用PIXE(Proton Induced X-ray Emission)分析技术获得S、K、Ca、Ti、Cr、Mn、Fe、Ni、Cu、Zn、As、Se、Br、Sr、Pb等15种元素的质量浓度.结果表明,上海PM2.5中化学元素的质量浓度在春季 (5?038.6 ng·m-3) 比在夏季 (3?810.6 ng·m-3) 高,春季郊区(2?528.9 ng·m-3) 和市区(2?509.7 ng·m-3) PM2.5中化学元素的质量浓度相当,夏季市区样品 (1?674.2 ng·m-3) 中化学元素质量浓度的总量比郊区(2?136.3 ng·m-3) 的低,但来自人为污染的化学元素 (Cr、Mn、Ti、Ni、Cu、Zn、As、Br、Sr、Pb) 在市区PM2.5中的含量较高;场发射扫描电镜 (FESEM) 分析显示,上海PM2.5主要由烟尘集合体、燃煤飞灰、矿物颗粒、生物质颗粒和不明物质组成,质粒DNA评价揭示上海市区PM2.5比郊区的具有更强的生物活性,主要原因可能在于市区样品中含有较高的重金属元素和较多的烟尘集合体. 相似文献
73.
A protocol was developed to fractionate soil particles down to the nanocolloid scale by combining sieving, sedimentation,
centrifugation, and cross-flow filtration (CFF). The validity of the method and the performance of the CFF system were tested
by characterizing fractions using laser granulometry, electron microscopy, and chemical analysis. The 0.1-μm-pore-size membrane
CFF system effectively retained nanocolloids (<0.1 μm) as shown by laser granulometry and observed directly by transmission
electron microscopy. However, environmental scanning electron microscopy images of freeze-dried colloids were very different
from their TEM counterparts, suggesting that sample preparation influenced microscopy imaging. Chemical analysis of Cu, Cd,
and organic carbon in each fraction showed that the concentrations of these components increased as particle size decreased,
indicating colloids and nanocolloids play an important role in retaining trace metals. Particle-size fractionation combined
with chemical analysis and electron microscopy can provide insight into the nature and properties of nanocolloids in soil. 相似文献
74.
为研究北极地区大气气溶胶颗粒的物理化学特性,于2013年8月8~12日环Svalbard岛收集大气气溶胶样品,利用带能谱的透射电子显微镜(TEM-EDS)共分析2530个单颗粒,并获得颗粒物的形貌特征和化学组成.结果表明,北极地区颗粒物主要表现为5种类型,分别为海盐颗粒、富S颗粒、富Fe颗粒、含碳颗粒和矿物颗粒.后向气流轨迹显示,采样期间大气污染物主要来自于北极点周边的海洋上空和附近格陵兰岛地区.来自海洋上空的大气中主要包含海盐颗粒,所占数量比例为54.7%;经过陆地的大气样品中95.4%为矿物颗粒.利用时间密度因子法估算出北极地区PM2.5质量浓度范围为0.55~0.72mg/m3. 相似文献
75.
Tianhao Xi Xiaodan Li Qihui Zhang Ning Liu Shu Niu Zhaojun Dong Cong Lyu 《Frontiers of Environmental Science & Engineering》2021,15(4):55
76.
Xie M.Wu Z.Wang X.Gu J.Chen L.Wang Y. 《应用与环境生物学报》2018,(4):915-920
In an effort to remove BDE-47 residues from the environment, a bacterial strain that is capable of utilizing BDE-47 as the sole carbon source was isolated and screened from soil collected from an e-waste recycling area in Tianjin to analyze the degradation properties. The strain was preliminarily identified as Enterobacter sp. according to a 16S rDNA gene sequence analysis. The strain degraded 35.8% of 525 μg/L of BDE-47 in 35 d when the initial concentration of bacteria was 7.1 × 105 cells/ mL. The product of the biodegradation of BDE-47 was BDE-28. The biodegradation of BDE-47 fit well with first-order kinetics, and its degradation kinetics was ln Ct = - 0.104t + 6.22. With the addition of an electron acceptor, such as Fe3+, SO4 2- and NO3 -, the BDE-47 degradation rate was significantly increased to 49.8%, 59.1%, and 67.3%, respectively. The above results revealed that the strain could degrade BDE-47, which is of importance in the application of environmental bioremediation of BDE-47. © 2018 Science Press. All rights reserved. 相似文献
77.
Caiyan Qu Lushan Li Fan Feng Kainian Jiang Xing Wu Muchuan Qin Jia Tang Xi Tang Ruiyang Xiao Di Wu Chongjian Tang 《Frontiers of Environmental Science & Engineering》2023,17(9):115
78.
Introduction The membrane bioreactors (MBRs) have shown many advantages over conventional activated sludge processes, which apply membrane modules instead of the secondary settle tank to make a better separation of the solids and liquid and have been grea… 相似文献
79.
Jing Gu Hongtao Yu Xie Quan Shuo Chen Junfeng Niu 《Frontiers of Environmental Science & Engineering》2020,14(4):72
80.
Chao Lu Kanglan Deng Chun Hu Lai Lyu 《Frontiers of Environmental Science & Engineering》2020,14(5):82