Conceptual design of a bioregenerative life support system containing crops and silkworms

This article summarizes a conceptual design of a bioregenerative life support system for permanent lunar base or planetary exploration. The system consists of seven compartments – higher plants cultivation, animal rearing, human habitation, water recovery, waste treatment, atmosphere management, and storages. Fifteen kinds of crops, such as wheat, rice, soybean, lettuce, and mulberry, were selected as main life support contributors to provide the crew with air, water, and vegetable food. Silkworms fed by crop leaves were designated to produce partial animal nutrition for the crew. Various physical-chemical and biological methods were combined to reclaim wastewater and solid waste. Condensate collected from atmosphere was recycled into potable water through granular activated carbon adsorption, iodine sterilization, and trace element supplementation. All grey water was also purified though multifiltration and ultraviolet sterilization. Plant residue, human excrement, silkworm feces, etc. were decomposed into inorganic substances which were finally absorbed by higher plants. Some meat, ingredients, as well as nitrogen fertilizer were prestored and resupplied periodically. Meanwhile, the same amount and chemical composition of organic waste was dumped to maintain the steady state of the system. A nutritional balanced diet was developed by means of the linear programming method. It could provide 2721 kcal of energy, 375.5 g of carbohydrate, 99.47 g of protein, and 91.19 g of fat per capita per day. Silkworm powder covered 12.54% of total animal protein intakes. The balance of material flows between compartments was described by the system of stoichiometric equations. Basic life support requirements for crews including oxygen, food, potable and hygiene water summed up to 29.68 kg per capita per day. The coefficient of system material closure reached 99.40%.     

Silkworms culture as a source of protein for humans in space

This paper focuses on the problem about a configuration with complete nutrition for humans in a Controlled Ecological Life Support System (CELSS) applied in the spacebases. The possibility of feeding silkworms to provide edible animal protein with high quality for taikonauts during long-term spaceflights and lunar-based missions was investigated from several aspects, including the nutrition structure of silkworms, feeding method, processing methods, feeding equipment, growing conditions and the influences on the space environmental condition changes caused by the silkworms. The originally inedible silk is also regarded as a protein source. A possible process of edible silk protein was brought forward in this paper. After being processed, the silk can be converted to edible protein for humans. The conclusion provides a promising approach to solving the protein supply problem for the taikonauts living in space during an extended exploration period.     

O2 evolution and cyclic electron flow around photosystem I in long-term ground batch culture of Euglena gracilis

Based on the purpose of better exploring the function of green producers in the closed aquatic biological life support system, the condition of dynamic O₂ evolution and performance of cyclic electron flow around photosystem I (CEF-PSI) in long-term ground batch culture of Euglena gracilis were studied, the relationship between linear electron flow (LEF) and CEF-PSI was revealed, the function of CEF-PSI was investigated. Excellent consistency in O₂ evolution pattern was observed in cultures grown in both closed and open containers, O₂ evolution was strictly suppressed in phase 1, but the rate of it increased significantly in phase 2. CEF-PSI was proposed to be active during the whole course of cultivation, even in the declining phase 3, it still operated at the extent of 47–55%. It is suggested that the relationship between LEF and CEF-PSI is not only competition but also reciprocity. CEF-PSI was proposed to contribute to the considerable growth in phase 1; it was also suggested to play an important protective role against photosystem II (PSII) photoinhibition at the greatly enhanced level (approximately 80–95%) on the 2nd day. Our results in this research suggest that E. gracilis had very particular photosynthetic characteristics, the strict O₂ evolution suppression in the initial culture phase might be a special light acclimation behavior, and CEF-PSI could be an important mechanism involved in this kind of adaptation to the changeable light environment.     

读解中西差异,实现习语翻译的文化传达

从部分中英习语着手,分析、归纳中英背景对语言产生深刻影响,中英文化差异在习语中的体现,说明理解文化背景在跨文化交际中的重要性。     

Initial ground experiments of silkworm cultures living on different feedstock for provision of high quality animal protein for human in space

Silkworm could be an alternative to provide edible animal protein in Controlled Ecological Life Support System (CELSS) for long-term manned space missions. Silkworms can consume non-edible plant residue and convert plant nutrients to high quality edible animal protein for astronauts. The preliminary investigation of silkworm culture was carried out in earth environment. The silkworms were fed with artificial silkworm diet and the leaves of stem lettuce (Lactuca sativa L. var. angustana Irish) separately and the nutritional structure of silkworm was investigated and compared, The culture experiments showed that: (1) Stem lettuce leaves could be used as food of silkworm. The protein content of silkworm fed with lettuce leaves can reach 70% of dry mass. (2) The protein content of silkworm powder produced by the fifth instar silkworm larvae was 70%, which was similar to the protein content of silkworm pupae. The powder of the fifth instar silkworm larvae can be utilized by astronaut. (3) The biotransformation rate of silkworm larvae between the third instar and the fifth instar could reach above 70%. The biotransformation cycle of silkworm was determined as 24 days. (4) Using the stem lettuce leaves to raise silkworm, the coarse fiber content of silkworm excrements reached about 33%. The requirements of space silkworm culture equipment, feeding approaches and feeding conditions were also preliminarily designed and calculated. It is estimated that 2.2 m³ of culture space could satisfy daily animal protein demand for seven astronauts.