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This article describes some of tasks carried out as a part of an international project ERA (Enhanced RPAS Automation, RPAS – Remotely Piloted Aircraft Systems). The works were focused on a control system for an optionally piloted aircraft MP-02 Czajka, especially on adapting the control system for piloting the aircraft in take-off and landing phases. The entry point was the control system built on using PID controllers in the aircraft. The quality of the control system was insufficient; especially for steering in critical flight states such as take-off and landing. The aim was to improve and fine-tune it to the object, which would allow to shorten time constants of the system, reduce overshoots and errors. It was decided to leave a general structure of a control algorithm based on PID controllers, however, it was extended with additional elements, among others blocks of additional damping, “fit forward” blocks and others. The article describes control laws and their modification as well as effects on steering in longitudinal motion, primarily an angle of pitch of the aircraft, as well as lateral movement, by controlling an angle of roll and a course of the aircraft.

In the near future, the integration of manned and unmanned aerial vehicles into the common airspace will proceed. The changes taking place mean that the safety of light aircraft, ultralight aircraft and unmanned air vehicles (UAV) will become an increasing problem. The IDAAS project (Intruder Detection And collision Avoidance System) meets the new challenges as it aims to produce technically advanced detection and collision avoidance systems for light and unmanned aerial vehicles. The work discusses selected elements of research and practical tests of the intruder detection vision system, which is part the of IDAAS project. At the outset, the current formal requirements related to the necessity of installing anticollision systems on aircraft are presented. The concept of the IDAAS system and the structure of algorithms related to image processing are also discussed. The main part of the work presents the methodology developed for the needs of dedicated flight tests, its implementation and the results obtained. The initial tests of the IDAAS system carried out on an ultralight aircraft generally indicate the possibility of the effective detection of intruders in the airspace with the use of vision methods, although they also indicated the existence of conditions in which this detection may prove difficult or even impossible.

This article proposes a vision-based method of determining in which of the three states, defined in the spin recovery process, is an aircraft. The correct identification of this state is necessary to make the right decisions during the spin recovery maneuver. The proposed solution employs a keypoints displacements analysis in consecutive frames taken from the on-board camera. The idea of voting on the temporary location of the rotation axis and dominant displacement direction was used. The decision about the state is made based on a proposed set of rules employing the histogram spread measure. To validate the method, experiments on flight simulator videos, recorded at varying altitudes and in different lighting, background, and visibility conditions, were carried out. For the selected conditions, the first flight tests were also performed. Qualitative and quantitative assessments were conducted using a multimedia data annotation tool and the Jaccard index, respectively. The proposed approach could be the basis for creating a solution supporting the pilot in the process of aircraft spin recovery and, in the future, the development of an autonomous method.

Mutations in the unc-23 gene in the free-living nematode, Caenorhabditis elegans result in detachment and dystrophy of the anterior body wall musculature and a bent-head phenotype when grown on solid substrate. We have determined that the unc-23 gene product is the nematode ortholog of the human BAG-2 protein, a member of the Bcl-2 associated athanogene (BAG) family of molecular chaperone regulators. We show that a functional GFP-tagged UNC-23 protein is expressed throughout development in several tissues of the animal, including body wall muscle and hypodermis, and associates with adhesion complexes and attachment structures within these 2 tissues. In humans, the BAG protein family consists of 6 members that all contain a conserved 45 amino acid BAG domain near their C-termini. These proteins bind to and modulate the activity of the ATPase domain of the heat shock cognate protein 70, Hsc70. We have isolated missense mutations in the ATPase domain of the C. elegans heat shock 70 protein, HSP-1 that suppress the phenotype exhibited by unc-23(e25) mutant hermaphrodites and we show that UNC-23 and HSP-1 interact in a yeast-2-hybrid system. The interaction of UNC-23 with HSP-1 defines a role for HSP-1 function in the maintenance of muscle attachment during development.

We identify cpna-1 (F31D5.3) as a novel essential muscle gene in the nematode Caenorhabditis elegans. Antibodies specific to copine domain protein atypical-1 (CPNA-1), as well as a yellow fluorescent protein translational fusion, are localized to integrin attachment sites (M-lines and dense bodies) in the body-wall muscle of C. elegans. CPNA-1 contains an N-terminal predicted transmembrane domain and a C-terminal copine domain and binds to the M-line/dense body protein PAT-6 (actopaxin) and the M-line proteins UNC-89 (obscurin), LIM-9 (FHL), SCPL-1 (SCP), and UNC-96. Proper CPNA-1 localization is dependent upon PAT-6 in embryonic and adult muscle. Nematodes lacking cpna-1 arrest elongation at the twofold stage of embryogenesis and display disruption of the myofilament lattice. The thick-filament component myosin heavy chain MYO-3 and the M-line component UNC-89 are initially localized properly in cpna-1-null embryos. However, in these embryos, when contraction begins, MYO-3 and UNC-89 become mislocalized into large foci and animals die. We propose that CPNA-1 acts as a linker between an integrin-associated protein, PAT-6, and membrane-distal components of integrin adhesion complexes in the muscle of C. elegans.

Determining the sub-cellular localization of a protein within a cell is often an essential step towards understanding its function. In Caenorhabditis elegans, the relatively large size of the body wall muscle cells and the exquisite organization of their sarcomeres offer an opportunity to identify the precise position of proteins within cell substructures. Our goal in this study is to generate a comprehensive "localizome" for C. elegans body wall muscle by GFP-tagging proteins expressed in muscle and determining their location within the cell. For this project, we focused on proteins that we know are expressed in muscle and are orthologs or at least homologs of human proteins. To date we have analyzed the expression of about 227 GFP-tagged proteins that show localized expression in the body wall muscle of this nematode (e.g. dense bodies, M-lines, myofilaments, mitochondria, cell membrane, nucleus or nucleolus). For most proteins analyzed in this study no prior data on sub-cellular localization was available. In addition to discrete sub-cellular localization we observe overlapping patterns of localization including the presence of a protein in the dense body and the nucleus, or the dense body and the M-lines. In total we discern more than 14 sub-cellular localization patterns within nematode body wall muscle. The localization of this large set of proteins within a muscle cell will serve as an invaluable resource in our investigation of muscle sarcomere assembly and function.

A crucial step in the development of muscle cells in all metazoan animals is the assembly and anchorage of the sarcomere, the essential repeat unit responsible for muscle contraction. In Caenorhabditis elegans, many of the critical proteins involved in this process have been uncovered through mutational screens focusing on uncoordinated movement and embryonic arrest phenotypes. We propose that additional sarcomeric proteins exist for which there is a less severe, or entirely different, mutant phenotype produced in their absence. We have used Serial Analysis of Gene Expression (SAGE) to generate a comprehensive profile of late embryonic muscle gene expression. We generated two replicate long SAGE libraries for sorted embryonic muscle cells, identifying 7,974 protein-coding genes. A refined list of 3,577 genes expressed in muscle cells was compiled from the overlap between our SAGE data and available microarray data. Using the genes in our refined list, we have performed two separate RNA interference (RNAi) screens to identify novel genes that play a role in sarcomere assembly and/or maintenance in either embryonic or adult muscle. To identify muscle defects in embryos, we screened specifically for the Pat embryonic arrest phenotype. To visualize muscle defects in adult animals, we fed dsRNA to worms producing a GFP-tagged myosin protein, thus allowing us to analyze their myofilament organization under gene knockdown conditions using fluorescence microscopy. By eliminating or severely reducing the expression of 3,300 genes using RNAi, we identified 122 genes necessary for proper myofilament organization, 108 of which are genes without a previously characterized role in muscle. Many of the genes affecting sarcomere integrity have human homologs for which little or nothing is known., Competing Interests: The authors have declared that no competing interests exist.

Embryos homozygous for mutations in the unc-52, pat-2, pat-3, and unc-112 genes of C. elegans exhibit a similar Pat phenotype. Myosin and actin are not organized into sarcomeres in the body wall muscle cells of these mutants, and dense body and M-line components fail to assemble. The unc-52 (perlecan), pat-2 (alpha-integrin), and pat-3 (beta-integrin) genes encode ECM or transmembrane proteins found at the cell-matrix adhesion sites of both dense bodies and M-lines. This study describes the identification of the unc-112 gene product, a novel, membrane-associated, intracellular protein that colocalizes with integrin at cell-matrix adhesion complexes. The 720-amino acid UNC-112 protein is homologous to Mig-2, a human protein of unknown function. These two proteins share a region of homology with talin and members of the FERM superfamily of proteins. We have determined that a functional UNC-112::GFP fusion protein colocalizes with PAT-3/beta-integrin in both adult and embryonic body wall muscle. We also have determined that UNC-112 is required to organize PAT-3/beta-integrin after it is integrated into the basal cell membrane, but is not required to organize UNC-52/perlecan in the basement membrane, nor for DEB-1/vinculin to localize with PAT-3/beta-integrin. Furthermore, UNC-112 requires the presence of UNC-52/perlecan and PAT-3/beta-integrin, but not DEB-1/vinculin to become localized to the muscle cell membrane.

The unc-52 gene encodes the nematode homologue of mammalian perlecan, the major heparan sulfate proteoglycan of the extracellular matrix. This is a large complex protein with regions similar to low-density lipoprotein receptors, laminin, and neural cell adhesion molecules (NCAMs). In this study, we extend our earlier work and demonstrate that a number of complex isoforms of this protein are expressed through alternative splicing. We identified three major classes of perlecan isoforms: a short form lacking the NCAM region and the C-terminal agrin-like region; a medium form containing the NCAM region, but still lacking the agrin-like region; and a newly identified long form that contains all five domains present in mammalian perlecan. Using region-specific antibodies and unc-52 mutants, we reveal a complex spatial and temporal expression pattern for these UNC-52 isoforms. As well, using a series of mutations affecting different regions and thus different isoforms of UNC-52, we demonstrate that the medium NCAM-containing isoforms are sufficient for myofilament lattice assembly in developing nematode body-wall muscle. Neither short isoforms nor isoforms containing the C-terminal agrin-like region are essential for sarcomere assembly or muscle cell attachment, and their role in development remains unclear.

Five formaldehyde-induced deficiencies that uncover unc-22 IV, a gene affecting muscle structure in the nematode Caenorhabditis elegans were isolated and positioned. The largest deficiency, sDf2, extends in both directions from unc-22 and is approximately 1.0-2.0 map units in length. The other four deficiencies, sDf7, sDf8, sDf9 and sDf10, are all smaller than sDf2 and are located within the region uncovered by this deficiency. Thirty-seven ethyl methane-sulfonate-induced lethal and sterile mutations linked to unc-22 were isolated and tested for complementation with sDf2. Nineteen lethal mutations failed to complement sDf2. Sixteen of these were further positioned by recombination mapping and also by deficiency mapping with sDf7, sDf8, sDf9 and sDf10. These sixteen mutations define 11 new essential genes in this region. Eight of the genes lie in a 0.9-map unit interval to the left of unc-22, whereas the three remaining genes lie in a region of about 0.2 map units to the right of unc-22. We believe that two of the essential genes identified in this study, let-56 and let-52, are the adjacent genes on either side of unc-22. The lethal mutations exhibit a wide range of terminal phenotypes: from first stage larva to sterile adult.