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With the development of technology, combined with the design concept of high integration, integration, modularization, and functional software, some missions that used to be performed by large satellites, such as those used for remote sensing, scientific experiments, and technical verification, has been possible through low-cost, short-cycle, high-performance small satellites and even mini/micro-satellites greatly increased the "functional density. "Under such a background, the commercial space company has an unprecedented development opportunity. In the past, there were no laws and regulations that required satellites to carry derailment devices. Some small satellites could go into orbit without any deorbit devices, which would lead to more space trash. With the introduction of regulatory policies, microsatellites, including CubeSat, are required to install deorbit devices before they enter orbit. Some orbits even require satellites to have the ability of active orbit transfer. Passive deorbit such as the deorbit-sail will be excluded. Therefore, in order to meet the new demand, it is urgent to develop an active orbit transfer system for microsatellites. This paper will take the power as the mainline, analyze several common electric propulsion systems with the parameters of thrust, specific impulse, total impulse, volume, and so on, and then give their applicable conditions.

Ethnopharmacological relevance Geniposide is derived from Gardenia jasminoides Ellis (Rubiaceae). Its anti-inflammatory, antithrombotic effects as well as its preventive effect against ischemic stroke have been reported. Radix notoginseng (Chinese name tienchi or sanqi) is the dried root of Panax notoginseng (Burk.) F.H. Chen, an herb noted for its promotion of blood circulation, blood stasis removal and pain alleviation, and has been widely utilized for the prevention and treatment of microcirculatory disturbances in China and other Asian countries for many years. Notoginsenoside R1 is an effective and structurally representative bioactive constituent of R. notoginseng. In our preliminary study, notoginsenoside R1 was able significantly to improve the bioavailability of geniposide in beagle dogs, but the underlying mechanisms remain unknown. Materials and Methods The present study aimed to investigate the intestinal kinetic absorptive characteristics of geniposide as well as the absorptive behavior influenced by the co-administration of notoginsenoside R1 using an in vitro everted rat gut sac model. Results The results showed good linear correlation between the geniposide absorption in sac contents and the incubation time from 0 to 120 min. The concentration dependence showed a non-linear correlation between the geniposide absorption and the concentrations 0.356–1.424 mg/mL, the absorption was saturated about 1.424 mg/mL. Notoginsenoside R1 at 0.1 and 0.2 mg/mL concentrations was able significantly to enhance the absorption of geniposide (1.424 mg/mL) by 1.7- and 1.4-fold. Moreover, verapamil, a well-known P-glycoprotein inhibitor, was able significantly to elevate the absorption of geniposide 2.4-fold. Notoginsenoside R1 influenced geniposide's absorption in a way similar to that of a P-glycoprotein inhibitor. Conclusions In conclusion, notoginsenoside R1 significantly enhances the intestinal absorption of geniposide. As for the mechanism underlying the improvement of geniposide's bioavailability, it is proposed that notoginsenoside R1 was able to decrease the efflux transport of geniposide by P-glycoproteins.

In recent years, increasing numbers of people have been choosing herbal medicines or products to improve their health conditions, either alone or in combination with others. Herbs are staging a comeback and herbal “renaissance” occurs all over the world. According to the World Health Organization, 75% of the world’s populations are using herbs for basic healthcare needs. Since the dawn of mankind, in fact, the use of herbs/plants has offered an effective medicine for the treatment of illnesses. Moreover, many conventional/pharmaceutical drugs are derived directly from both nature and traditional remedies distributed around the world. Up to now, the practice of herbal medicine entails the use of more than 53,000 species, and a number of these are facing the threat of extinction due to overexploitation. This paper aims to provide a review of the history and status quo of Chinese, Indian, and Arabic herbal medicines in terms of their significant contribution to the health promotion in present-day over-populated and aging societies. Attention will be focused on the depletion of plant resources on earth in meeting the increasing demand for herbs.

With tens of thousands of plant species on earth, we are endowed with an enormous wealth of medicinal remedies from Mother Nature. Natural products and their derivatives represent more than 50% of all the drugs in modern therapeutics. Because of the low success rate and huge capital investment need, the research and development of conventional drugs are very costly and difficult. Over the past few decades, researchers have focused on drug discovery from herbal medicines or botanical sources, an important group of complementary and alternative medicine (CAM) therapy. With a long history of herbal usage for the clinical management of a variety of diseases in indigenous cultures, the success rate of developing a new drug from herbal medicinal preparations should, in theory, be higher than that from chemical synthesis. While the endeavor for drug discovery from herbal medicines is “experience driven,” the search for a therapeutically useful synthetic drug, like “looking for a needle in a haystack,” is a daunting task. In this paper, we first illustrated various approaches of drug discovery from herbal medicines. Typical examples of successful drug discovery from botanical sources were given. In addition, problems in drug discovery from herbal medicines were described and possible solutions were proposed. The prospect of drug discovery from herbal medicines in the postgenomic era was made with the provision of future directions in this area of drug development.