Preliminary observation results of the Coherent Beacon Systemonboard the China Seismo-Electromagnetic Satellite-1

This paper reports, for the first time, observation results of the Coherent Beacon System(CBS) onboard the China SeismoElectromagnetic Satellite-1(CSES-1). We describe the CBS, and the Computerized Ionospheric Tomography(CIT) algorithm program is validated by numerical experiment. Two examples are shown, for daytime and nighttime respectively. The Equatorial Ionization Anomaly(EIA) can be seen, and the northern crest core is located at ～20°N in the reconstruction image at 07:28 UTC on 20 July 2018(daytime).Disturbances are shown in the reconstruction image at 18:40 UTC on 13 July 2018(nighttime). We find that beacon measurements are more consistent with ionosonde measurements than model results, by comparing Nm F2 at three sites at Lanzhou, Chongqing, and Kunming; consistency with ionosonde measurements validates beacon measurements. Finally, we have studied Vertical Total Electron Content(VTEC) variations from ground to ～500 km(the height of CSES-1 orbit) and ratios of VTEC between beacon measurements and CODE(Center for Orbit Determination in Europe) data. VTEC variation from ground to ～500 km has a range of 7.2–16.5 TECU for the daytime case and a range of 1.1–1.7 TECU for the nighttime case. The Beacon/CODE ratio of VTEC varies with latitude and time. The mean Beacon/CODE ratio is 0.69 for the daytime case and 0.26 for the nighttime case. The fact that the nighttime case yields lower ratios indicates the higher altitude of the ionosphere during nighttime when the ionosphere is assumed to be a thin layer.

Using endogenous glycogen as relaxation agent for imaging liver metabolism by MRI

Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has become the mainstream method for monitoring glycogen in the body.However,the equipment of special hard-ware to standard clinical magnetic resonance imaging(MRI)scanners limits its clinical applications.Herein,we utilized endogenous glycogen as a T_(2)-based relaxation contrast agent for imaging glycogen metabolism in the liver in vivo.The in vitro results demonstrated that the transverse relaxation rate of glycogen strongly correlates with the concentration,pH,and field strength.Based on the Swift-Connick theory,we characterized the exchange property of glycogen and measured the exchange rate of glycogen as 31,847 Hz at 37°C.Besides,the viscosity and echo spacing showed no apparent effect on the transverse relaxation rate.This unique feature enables vi-sualization of glycogen signaling in vivo through T_(2)-weighted MRI.Two hours-post intraperitoneal injection of glucagon,a clinical drug to promote glycogenolysis and gluconeogenesis,the signal intensity of the mice’s liver increased by 1.8 times from the T_(2)-weighted imaging experiment due to the decomposition of glycogen.This study provides a convenient imaging strategy to non-invasively investigate glycogen metabolism in the liver,which may find clinical applications in metabolic diseases.

中药蛴螬多肽Probrelin抗白色念珠菌活性研究

【目的】研究蛴螬多肽Probrelin对白色念珠菌的抗菌活性。【方法】采用肉汤稀释法测定蛴螬多肽Probrelin对正常菌株及临床耐药菌株的最小抑菌浓度,同时结合平板计数法测定最小杀真菌浓度;通过不同浓度多肽处理后经平板计数绘制时间-杀菌动力学曲线;通过PI吸收实验检测多肽对白色念珠菌细胞膜完整性的影响;通过核酸阻滞实验检测多肽与核酸间是否具有结合作用;通过扫描电子显微镜检测多肽对白色念珠菌形态的影响;通过结晶紫染色法检测多肽对生物膜生成及成熟生物膜的影响;通过显微镜观察多肽对白色念珠菌菌丝形成的影响;通过棋盘法检测多肽与抗真菌药物间的相互效应;通过小鼠皮下感染模型检测多肽在生理条件下的抗白色念珠菌活性。【结果】蛴螬多肽Probrelin对正常菌株及临床耐药菌株的最小抑菌浓度均为100μg/mL,最小杀真菌浓度为100–200μg/mL,且对白色念珠菌的杀菌动力学具有时间和浓度依赖性;该多肽以浓度依赖性的方式影响白色念珠菌细胞膜的完整性,并通过破坏白色念珠菌细胞壁的结构影响其形态,但与核酸间不具有结合作用;该多肽既可抑制白色念珠菌生物膜的形成,又可清除成熟生物膜,同时还可抑制白色念珠菌菌丝的形成;该多肽与抗真菌药物Clotrimazole间具有协同效应;在小鼠皮下感染模型中,该多肽可以有效杀灭白色念珠菌,进而抑制感染。【结论】蛴螬多肽Probrelin对白色念珠菌具有良好的抑制杀灭活性,可以作为新的药物分子或模板分子用于抗白色念珠菌药物的研发。