Testing and Validation of the Dynamic Inertia Measurement Method

The Dynamic Inertia Measurement (DIM) method uses a ground vibration test setup to determine the mass properties of an object using information from frequency response functions. Most conventional mass properties testing involves using spin tables or pendulum-based swing tests, which for large aerospace vehicles becomes increasingly difficult and time-consuming, and therefore expensive, to perform. The DIM method has been validated on small test articles but has not been successfully proven on large aerospace vehicles. In response, the National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) conducted mass properties testing on an "iron bird" test article that is comparable in mass and scale to a fighter-type aircraft. The simple two-I-beam design of the "iron bird" was selected to ensure accurate analytical mass properties. Traditional swing testing was also performed to compare the level of effort, amount of resources, and quality of data with the DIM method. The DIM test showed favorable results for the center of gravity and moments of inertia; however, the products of inertia showed disagreement with analytical predictions

Experimental Validation of the Dynamic Inertia Measurement Method to Find the Mass Properties of an Iron Bird Test Article

The mass properties of an aerospace vehicle are required by multiple disciplines in the analysis and prediction of flight behavior. Pendulum oscillation methods have been developed and employed for almost a century as a means to measure mass properties. However, these oscillation methods are costly, time consuming, and risky. The NASA Armstrong Flight Research Center has been investigating the Dynamic Inertia Measurement, or DIM method as a possible alternative to oscillation methods. The DIM method uses ground test techniques that are already applied to aerospace vehicles when conducting modal surveys. Ground vibration tests would require minimal additional instrumentation and time to apply the DIM method. The DIM method has been validated on smaller test articles, but has not yet been fully proven on large aerospace vehicles

Исследование влияния солей лития на жизнеспособность бактерий E.coli

В работе исследовано влияние органических солей лития на жизнеспособность и метаболизм культуры E. coli. Установлено, что соли пирувата и сукцината лития не обладают токсичностью в концентрациях от 1,28 до 21,28 ммоль/л. Выявлено, что с увеличением концентрации сукцината и пирувата лития возрастает жизнеспособность культуры E. coli при культивировании на благоприятной и обеднённой питательных средах. Обнаружено, что добавление пирувата и сукцината лития влияет на биохимические процессы бактериальной клетки.The effect of organic lithium salts on the viability and metabolism of E. coli bacteria is investigated. It was found that the salts of lithium pyruvate and succinate do not have toxicity in concentrations from 1.28 to 21.28 mmol/l. It was found that lithium salts at the concentration of 12.77 and 21.28 mmol/l lead to growth increasing of E. coli bacteria in beef-extract broth and a physiological salt solution. It was found that the addition of lithium pyruvate and lithium succinate affects the biochemical processes of the bacterial cell

Instability of Plastid DNA in the Nuclear Genome

Functional gene transfer from the plastid (chloroplast) and mitochondrial genomes to the nucleus has been an important driving force in eukaryotic evolution. Non-functional DNA transfer is far more frequent, and the frequency of such transfers from the plastid to the nucleus has been determined experimentally in tobacco using transplastomic lines containing, in their plastid genome, a kanamycin resistance gene (neo) readymade for nuclear expression. Contrary to expectations, non-Mendelian segregation of the kanamycin resistance phenotype is seen in progeny of some lines in which neo has been transferred to the nuclear genome. Here, we provide a detailed analysis of the instability of kanamycin resistance in nine of these lines, and we show that it is due to deletion of neo. Four lines showed instability with variation between progeny derived from different areas of the same plant, suggesting a loss of neo during somatic cell division. One line showed a consistent reduction in the proportion of kanamycin-resistant progeny, suggesting a loss of neo during meiosis, and the remaining four lines were relatively stable. To avoid genomic enlargement, the high frequency of plastid DNA integration into the nuclear genome necessitates a counterbalancing removal process. This is the first demonstration of such loss involving a high proportion of recent nuclear integrants. We propose that insertion, deletion, and rearrangement of plastid sequences in the nuclear genome are important evolutionary processes in the generation of novel nuclear genes. This work is also relevant in the context of transgenic plant research and crop production, because similar processes to those described here may be involved in the loss of plant transgenes

Recombinase technology: applications and possibilities

The use of recombinases for genomic engineering is no longer a new technology. In fact, this technology has entered its third decade since the initial discovery that recombinases function in heterologous systems (Sauer in Mol Cell Biol 7(6):2087–2096, 1987). The random insertion of a transgene into a plant genome by traditional methods generates unpredictable expression patterns. This feature of transgenesis makes screening for functional lines with predictable expression labor intensive and time consuming. Furthermore, an antibiotic resistance gene is often left in the final product and the potential escape of such resistance markers into the environment and their potential consumption raises consumer concern. The use of site-specific recombination technology in plant genome manipulation has been demonstrated to effectively resolve complex transgene insertions to single copy, remove unwanted DNA, and precisely insert DNA into known genomic target sites. Recombinases have also been demonstrated capable of site-specific recombination within non-nuclear targets, such as the plastid genome of tobacco. Here, we review multiple uses of site-specific recombination and their application toward plant genomic engineering. We also provide alternative strategies for the combined use of multiple site-specific recombinase systems for genome engineering to precisely insert transgenes into a pre-determined locus, and removal of unwanted selectable marker genes

Function of defensive volatiles in pedunculate oak (<em>Quercus robur</em>) is tricked by the moth <em>Tortrix viridana</em>.

The indirect defences of plants are comprised of herbivore-induced plant volatiles (HIPVs) that among other things attract the natural enemies of insects. However, the actual extent of the benefits of HIPV emissions in complex co-evolved plant-herbivore systems is only poorly understood. The observation that a few Quercus robur L. trees constantly tolerated (T-oaks) infestation by a major pest of oaks (Tortrix viridana L.), compared with heavily defoliated trees (susceptible: S-oaks), lead us to a combined biochemical and behavioural study. We used these evidently different phenotypes to analyse whether the resistance of T-oaks to the herbivore was dependent on the amount and scent of HIPVs and/or differences in non-volatile polyphenolic leaf constituents (as quercetin-, kaempferol- and flavonol glycosides). In addition to non-volatile metabolic differences, typically defensive HIPV emissions differed between S-oaks and T-oaks. Female moths were attracted by the blend of HIPVs from S-oaks, showing significantly higher amounts of (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E)-&beta;-ocimene and avoid T-oaks with relative high fraction of the sesquiterpenes &alpha;-farnesene and germacrene D. Hence, the strategy of T-oaks exhibiting directly herbivore-repellent HIPV emissions instead of high emissions of predator-attracting HIPVs of the S-oaks appears to be the better mechanism for avoiding defoliation