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As manned space missions become longer and go farther away (i.e., Mars missions), the cost of resupply missions becomes substantial and even impractical. In order to reduce the logistics penalty for air revitalization in manned spacecraft, breathing oxygen (O2) must be recovered from metabolic carbon dioxide (CO2). The Sabatier CO2 reduction system is a key component of an integrated air revitalization system. The heart of the Sabatier system is the chemical catalyst bed that reacts carbon dioxide with hydrogen to form methane and water. Product water from a Sabatier subsystem would positively affect the current International Space Station (ISS) water balance and Mars missions would also benefit from the use of product methane as a propellant. This article focuses on the potential benefits of using the Sabatier subsystem for ISS and potential Mars mission applications.

Prior to ribosome assembly, 5S ribosomal RNA (5S rRNA) binds to ribosomal protein L5 to form a stable ribonucleoprotein particle (5S RNP). We have analyzed the role of L5 binding in the nuclear targeting of 5S rRNA in Xenopus oocytes, and have compared the nuclear import pathway of 5S RNPs with other karyophilic molecules. Nuclear import of in vitro-generated 5S RNPs was found to be sensitive to three general inhibitors of nuclear pore complex-mediated translocation: ATP depletion, chilling, and wheat germ agglutinin. The initial rate and extent of net nuclear import was threefold greater with preassembled 5S RNPs than with 5S rRNA microinjected alone, suggesting that L5 binding is a prerequisite for nuclear accumulation. Nuclear import of 5S rRNA/5S RNPs is a facilitated process dependent on limiting factors, since nuclear import exhibited saturation kinetics. Not only was nuclear import of labeled 5S rRNA reduced in the presence of excess unlabeled 5S rRNA, but also in the presence of the synthetic karyophilic protein P(lys)-BSA. In contrast, import was not inhibited by U1 small nuclear RNA (snRNA) or U3 small nucleolar RNA (snoRNA). 5S rRNA/5S RNP nuclear import therefore appears to follow a pathway of molecular interactions similar to many karyophilic proteins, but not the methylguanosine cap-dependent U1 snRNA pathway or the cap-independent U3 snoRNA pathway.

Twenty-five girls who survived the sinking of the cruise ship 'Jupiter' were compared with three other groups of girls--71 controls from a separate school; 46 girls in the same school who had not wanted to go on the cruise; and 13 girls who were in a 'near miss' group in that they wanted to go but did not get places. All completed the Fear Survey Schedule for Children (revised form), the Children's Manifest Anxiety Scale and the Birleson Depression Inventory. Survivors did not become generally more fearful. Rather, they developed significantly greater fears to stimuli related to the traumatic event. The results are discussed in relation to the conditioning theory of the acquisition of phobias.

Methods have been developed for the isolation of aleurone protoplasts from developing caryopses of Hordeum vulgare and Triticum aestivum in order to study transient expression of introduced genes. Chimaeric gene constructs were introduced into aleurone protoplasts by polyethylene glycol (PEG). Transient expression directed by the 35S promoter from cauliflower mosaic virus (CaMV) of the reporter gene encoding chloramphenicol acetyl transferase (CAT) was detected in aleurone protoplasts from developing barley and wheat grains. Using a similar construct, CAT activity increased when the alcohol dehydrogenase intron 1 fragment from maize was ligated between the 35S promoter and the CAT coding region. The demonstration of transient expression in protoplasts from developing aleurone layers indicates that they may be useful for investigating tissue and developmental control of genes coding for cereal seed proteins.

Water-lead levels were measured in the homes occupied during the first year of life by 77 mentally retarded children aged two to six years and 77 non-retarded matched controls, and in the homes occupied by their mothers during pregnancy. The water-lead content was significantly higher in the retarded group, and the probability of mental retardation was significantly increased when water lead exceeded 800 mug. per litre. Blood-lead levels were also significantly higher in the retarded group. It is concluded that lead contamination of water may be one factor in the multifactorial aetiology of mental retardation and that every effort should be made to reduce the lead content of drinking-water.