Oxygenated fatty acids of oil from sunflower seeds after prolonged storage

Chemical analysis of a number of sunflower (Helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide-reactive material. To characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from Uruguay, Turkey, and Yugoslavia that had been subjected to prolonged storage. Two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combination of column chromatography and countercurrent distribution. The epoxy acids arecis-9,10-epoxystearic acid (0.5%) andcis-9,10-epoxy-cis-12-octadecenoic (coronaric) acid (2.2%). Characterization of the dienols revealed that they are 9-hydroxy-trans-10,cis-12-octadecadienoic acid (1.2%) and 13-hydroxy-cis-9,trans-11-octadecadienoic acid (1.3%). Fresher seed of some of these introductions contained less of the oxygenated components. Oil from recently produced seed of selected high-oil Russian sunflower varieties, including some currently grown in the United States, contained no more than trace amounts of oxygenated acids. Though the relative contributions of genetic and environmental factors toward genesis of oxygenated acids are not established, increase of those acids in some sunflower lines as a result of storage has been demonstrated. Presented at the AOCS-AACC Joint Meeting, Washington, D. C., April 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Age Replacement In Simple Systems With Increasing Loss Functions

Some age replacement policies are investigated and conditions for the unique existence of an optimum policy are derived. The optimum policy is the one which minimizes the expected cost per unit time over an infinite time span or maximizes the proportion of time during which the system is in operation. Losses have been expressed through increasing operating cost, if the objective is to minimize the expected total cost per unit time and through increasing renewal times if the objective is to maximize the availability of the system.     

Overdamped nonlinear systems

Overdamped solutions toddot{z} + KF(z, dot{z}) = 0, z(0) = z_{0}, dot{z}(0) = dot{z}_{0}, are defined to be those that are asymptotically stable to the origin and which are zero at most once for0 < t < x. The main result is a lower bound on the positive constantKto ensure that solutions to the equation are overdamped.     

Alanine : glyoxylate aminotransferase of Saccharomyces cerevisiae-encoding gene AGX1 and metabolic significance

Alanine : glyoxylate aminotransferase is one of three different enzymes used for glycine synthesis in Saccharomyces cerevisiae. The open reading frame YFL030w (named AGX1 in the following), encoding this enzyme, was identified by comparing enzyme specific activities in knockout strains. While 100% activity was detectable in the parental strain, 2% was found in a YFL030w::kanMX4 strain. The ORF found at that locus was suspected to encode alanine : glyoxylate aminotransferase because its predicted amino acid sequence showed 23% identity to the human homologue. Since the YFL030w::kanMX4 strain showed no glycine auxtrophic phenotype, AGX1 was replaced by KanMX4 in a Delta GLY1 Delta SHM1 Delta SHM2 background. These background mutations, which cause inactivation of threonine aldolase, mitochondrial and cytosolic serine hydroxymethyltransferase, respectively, lead to a conditional glycine auxotrophy. This means that growth is not possible on glucose but on ethanol as the sole carbon source. Additional disruption of AGX1 revealed a complete glycine auxotrophy. Complementation was observed by transformation with a plasmid-encoded AGX1.     

Rooming-in at the maternity department. Results of a questionnaire-action

The authors report from the Univ.-Frauenklinik in Giessen, where rooming-in was first introduced in 1976; the newborn baby's bed is now put in the mother's room. When 171 outpatients, who had never heard of rooming-in, and 81 patients in the maternity ward were consulted, the women agreed to a trial period for rooming-in. It was shown that more than 70% of the women would have prefered a clinic where rooming-in was possible to a traditional type clinic. This tendency was particularly strongly felt among women with a higher level of secondary education and among women who held the view that the fathers should be more involved in the family and in the upbringing of small children. The results of individual questionnaires showed that support for rooming-in was significantly strong on the grounds of interhuman relations; also, the rejection of the traditional mother-image was apparent. Reasons for the introduction of rooming-in, as well as the difficulties involved in putting it into practice are outlined.     

SEM studies of the morphology and chemistry of polar ice

Determining the microphysical location of impurities in natural ice from the polar regions is necessary for understanding the physical properties of ice and for assuring the integrity of ice core records. SEM, using a cold stage and X-ray microanalytical techniques, has proved to be the most powerful method so far for undertaking such work. Methods are adapted from those used to study frozen hydrated biological material. Sublimation within the cryo-chamber is often needed in order to concentrate impurities onto a plane, but this can lead to artifacts that must be recognized. Over 100 samples from different depths and sites in Greenland and Antarctica have been examined. Typical physical features, including air bubbles, clathrate hydrates of air, and dust particles are identified. The dust is found preferentially at grain boundaries in some samples; by pinning the boundaries, it can slow grain growth. Of the soluble material, chloride seems to be found most frequently in the ice lattice. Other impurities are found at grain boundaries, and only when the bulk concentration exceeds a threshold, at triple junctions. These findings give new insights into processes determining the physical properties of ice samples and of ice sheets, and new impetus for theoretical studies of the energetics that lead to this distribution.     

A new Δ7-polyunsaturated fatty acid in taxus spp. Seed lipids, dihomotaxoleic (7,11–20∶2) acid

A previously undescribed fatty acid, all-cis 7, 11–20∶2 (dihomotaxoleic acid, DHT), has been characterized by gas chromatography-mass spectrometry as being present (approximately 0.1%) in seed oils of two Taxaceae containing high levels (11–16%) of taxoleic acid (all-cis 5,9–18∶2). This compound was absent from oils of 10 other conifer genera, as well as from one member of Taxaceae containing very low amounts of taxoleic acid, suggesting that DHT is a taxoleic acid elongation product.     

The structural efficiency of orthotropic stalks,stems and tubes

An optimised structure is one which uses the smallest quantity of the best material to perform its function, with adequate safety factor or margin for error. Structural optimisation occurs not only in mechanical engineering, but also in nature: plants with hollow stems or stalks gain a height advantage, and are thus more efficient, by approaching the optimum shape. Here we consider the optimisation of orthotropic tubes, typifying, in a mechanical sense, stalk and stem. The stiffness and strength of orthotropic tubes of initially circular section are reviewed, and diagrams are proposed which allow the optimum section shape to be selected.