MOLECULAR COMPUTING WITH TEST TUBE SYSTEMS

In this paper a survey of various different theoretical models of test tube systems is given. In test tube systems specific operations are applied to the objects in their components (test tubes) in a distributed and parallel manner; the results of these computations are redistributed according to a given output/input relation using specific filters. A general theoretical framework for test tube systems is presented which is not only a theoretical basis of systems used for practical applications, but also covers the theoretical models of test tube systems based on the splicing operation as well as of test tube systems based on the operations of cutting and recombination. For test tube systems based on the operations of cutting and recombination we show that in one test tube from a finite set of axioms and with a finite set of cutting and recombination rules only regular languages can evolve

Drip and Mate Operations Acting in Test Tube Systems and Tissue-like P systems

The operations drip and mate considered in (mem)brane computing resemble the operations cut and recombination well known from DNA computing. We here consider sets of vesicles with multisets of objects on their outside membrane interacting by drip and mate in two different setups: in test tube systems, the vesicles may pass from one tube to another one provided they fulfill specific constraints; in tissue-like P systems, the vesicles are immediately passed to specified cells after having undergone a drip or mate operation. In both variants, computational completeness can be obtained, yet with different constraints for the drip and mate operations

Conventional Industrial Robotics Applied to the Process of Tomato Grafting Using the Splicing Technique

Horticultural grafting is routinely performed manually, demanding a high degree of concentration and requiring operators to withstand extreme humidity and temperature conditions. This article presents the results derived from adapting the splicing technique for tomato grafting, characterized by the coordinated work of two conventional anthropomorphic industrial robots with the support of low-cost passive auxiliary units for the transportation, handling, and conditioning of the seedlings. This work provides a new approach to improve the efficiency of tomato grafting. Six test rates were analyzed, which allowed the system to be evaluated across 900 grafted units, with gradual increases in the speed of robots work, operating from 80 grafts/hour to over 300 grafts/hour. The results obtained show that a higher number of grafts per hour than the number manually performed by skilled workers could be reached easily, with success rates of approximately 90% for working speeds around 210–240 grafts/hour

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Activity-regulated RNA editing in select neuronal subfields in hippocampus

RNA editing by adensosine deaminases is a widespread mechanism to alter genetic information in metazoa. In addition to modifications in non-coding regions, editing contributes to diversification of protein function, in analogy to alternative splicing. However, although splicing programs respond to external signals, facilitating fine tuning and homeostasis of cellular functions, a similar regulation has not been described for RNA editing. Here, we show that the AMPA receptor R/G editing site is dynamically regulated in the hippocampus in response to activity. These changes are bi-directional, reversible and correlate with levels of the editase Adar2. This regulation is observed in the CA1 hippocampal subfield but not in CA3 and is thus subfield/celltype-specific. Moreover, alternative splicing of the flip/flop cassette downstream of the R/G site is closely linked to the editing state, which is regulated by Ca(2+). Our data show that A-to-I RNA editing has the capacity to tune protein function in response to external stimuli

Steric antisense inhibition of AMPA receptor Q/R editing reveals tight coupling to intronic editing sites and splicing

Adenosine-to-Inosine (A-to-I) RNA editing is a post-transcriptional mechanism, evolved to diversify the transcriptome in metazoa. In addition to wide-spread editing in non-coding regions protein recoding by RNA editing allows for fine tuning of protein function. Functional consequences are only known for some editing sites and the combinatorial effect between multiple sites (functional epistasis) is currently unclear. Similarly, the interplay between RNA editing and splicing, which impacts on post-transcriptional gene regulation, has not been resolved. Here, we describe a versatile antisense approach, which will aid resolving these open questions. We have developed and characterized morpholino oligos targeting the most efficiently edited site--the AMPA receptor GluA2 Q/R site. We show that inhibition of editing closely correlates with intronic editing efficiency, which is linked to splicing efficiency. In addition to providing a versatile tool our data underscore the unique efficiency of a physiologically pivotal editing site