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At least 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS2012

Seal with integrated shroud for androgenous docking and berthing in contaminated environments

The present invention is directed to a specially configured seal system which provides a barrier to gas leakage flow between a pressurized module and its external environment. The seal includes a shroud covering which protects the sealing interface from its environment when not in use, and retracts to expose the sealing interface when mated. The seal system is constructed and arranged to mate with a seal of identical construction and arrangement or to mate with a flat surface.

Daniels, Christopher C.↗

NASA NTRS2012

A Comparison of Candidate Seal Designs for Future Docking Systems

NASA is developing a new docking system to support future space exploration missions to low Earth orbit, the Moon, and other destinations. A key component of this system is the seal at the main docking interface which inhibits the loss of cabin air once docking is complete. Depending on the mission, the seal must be able to dock in either a seal-on-flange or seal-on-seal configuration. Seal-on-flange mating would occur when a docking system equipped with a seal docks to a system with a flat metal flange. This would occur when a vehicle docks to a node on the International Space Station. Seal-on-seal mating would occur when two docking systems equipped with seals dock to each other. Two types of seal designs were identified for this application: Gask-O-seals and multi-piece seals. Both types of seals had a pair of seal bulbs to satisfy the redundancy requirement. A series of performance assessments and comparisons were made between the candidate seal designs indicating that they meet the requirements for leak rate and compression and adhesion loads under a range of operating conditions. Other design factors such as part count, integration into the docking system tunnel, seal-on-seal mating, and cost were also considered leading to the selection of the multi-piece seal design for the new docking system. The results of this study can be used by designers of future docking systems and other habitable volumes to select the seal design best-suited for their particular application.

Dunlap, Patrick, H., Jr.↗

NASA NTRS2016

Apparatus, Systems, and Methods for Reconfigurable Robotic Manipulator and Coupling

A robotic manipulator arm is disclosed. The arm includes joints that are attachable and detachable in a tool-free manner via a universal mating adapter. The universal mating adapter includes a built-in electrical interface for an operative electrical connection upon mechanical coupling of the adapter portions. The universal mating adapter includes mechanisms and the ability to store and communicate parameter configurations such that the joints can be rearranged for immediate operation of the arm without further reprogramming, recompiling, or other software intervention.

Burridge, Robert Raven↗

NASA NTRS2016

International Docking Standard (IDSS) Interface Definition Document (IDD) : Revision - E

This International Docking System Standard (IDSS) Interface Definition Document (IDD) is the result of a collaboration by the International Space Station membership to establish a standard docking interface to enable on-orbit crew rescue operations and joint collaborative endeavors utilizing different spacecraft. This IDSS IDD details the physical geometric mating interface and design loads requirements. The physical geometric interface requirements must be strictly followed to ensure physical spacecraft mating compatibility. This includes both defined components and areas that are void of components. The IDD also identifies common design parameters as identified in section 3.0, e.g., docking initial conditions and vehicle mass properties. This information represents a recommended set of design values enveloping a broad set of design reference missions and conditions, which if accommodated in the docking system design, increases the probability of successful docking between different spacecraft. This IDD does not address operational procedures or off-nominal situations, nor does it dictate implementation or design features behind the mating interface. It is the responsibility of the spacecraft developer to perform all hardware verification and validation, and to perform final docking analyses to ensure the needed docking performance and to develop the final certification loads for their application. While there are many other critical requirements needed in the development of a docking system such as fault tolerance, reliability, and environments (e.g. vibration, etc.), it is not the intent of the IDSS IDD to mandate all of these requirements; these requirements must be addressed as part of the specific developer's unique program, spacecraft and mission needs. This approach allows designers the flexibility to design and build docking mechanisms to their unique program needs and requirements. The purpose of the IDSS IDD is to provide basic common design parameters to allow developers to independently design compatible docking systems. The IDSS is intended for uses ranging from crewed to autonomous space vehicles, and from Low Earth Orbit (LEO) to deep-space exploration missions.The purpose of the IDSS IDD is to provide basic common design parameters to allow developers to independently design compatible docking systems. The IDSS is intended for uses ranging from crewed to autonomous space vehicles, and from Low Earth Orbit (LEO) to deep-space exploration missions. The purpose of the IDSS IDD is to provide basic common design parameters to allow developers to independently design compatible docking systems. The IDSS is intended for uses ranging from crewed to autonomous space vehicles, and from Low Earth Orbit (LEO) to deep-space exploration missions.

docking↗

NASA NTRS2017

Link!: Potential Field Guidance Algorithm for In-Flight Linking of Multi-Rotor Aircraft

Link! is a multi-center NASA e ort to study the feasibility of multi-aircraft aerial docking systems. In these systems, a group of vehicles physically link to each other during flight to form a larger ensemble vehicle with increased aerodynamic performance and mission utility. This paper presents a potential field guidance algorithm for a group of multi-rotor vehicles to link to each other during flight. The linking is done in pairs. Each vehicle first selects a mate. Then the potential field is constructed with three rules: move towards the mate, avoid collisions with non-mates, and stay close to the rest of the group. Once a pair links, they are then considered to be a single vehicle. After each pair is linked, the process repeats until there is only one vehicle left. The paper contains simulation results for a system of 16 vehicles.

Cooper, John R.↗

NASA NTRSDate not supplied

Space Shuttle Program Dual Docked Operations

- Dual Docked Operations (DDO) is the docking or undocking of a Russian Vehicle (RV) during Space Shuttle Orbiter/International Space Station (ISS) mated operations. - This paper and presentation summarizes the concept definition, studies, and analysis results generated by the Space Shuttle Program (SSP), ISS Program (ISSP), and Mission Operations Directorate for implementing DDO during mated Orbiter/ISS missions. [1] - Due to the ever-increasing visiting vehicle traffic to and from the ISS, it became apparent to both the ISSP and the SSP that there would arise occasions where conflicts between a visiting vehicle docking and/or undocking could overlap with a planned Space Shuttle launch and/or during mated Orbiter/ISS operations. - This potential conflict provided the genesis for evaluating risk mitigations to gain maximum flexibility for managing potential visiting vehicle traffic to and from the ISS and to maximize launch and landing opportunities for all visiting vehicles. - Reviews were conducted to assess the viability and readiness of the SSP to protect for DDO on any given mission and it was found to be t echnically feasible

Launch vehicles↗

NASA NTRS2023

Space Shuttle Program Dual Docked Operations

Launch vehicles↗

DOE OSTI2021

Draft genome sequences of strains CBS6241 and CBS6242 of the basidiomycetous yeast Filobasidium floriforme

The Tremellomycetes are a species-rich group within the basidiomycete fungi; however, most analyses of this group to date have focused on pathogenic Cryptococcus species within the order Tremellales. Recent genome-assisted studies of other Tremellomycetes have identified interesting features with respect to biotechnological applications as well as the evolution of genes involved in mating and sexual development. Here, we report genome sequences of two strains of Filobasidium floriforme, a species from the order Filobasidiales, which branches basally to the Tremellales, Trichosporonales, and Holtermanniales. The assembled genomes of strains CBS6241 and CBS6242 are 27.4 Mb and 26.4 Mb in size, respectively, with 8314 and 7695 predicted protein-coding genes. Overall sequence identity at nucleic acid level between the strains is 97%. Among the predicted genes are pheromone precursor and pheromone receptor genes as well as two genes encoding homedomain (HD) transcription factors, which are predicted to be part of the mating type (MAT) locus. Sequence analysis indicates that CBS6241 and CBS6242 carry different alleles for both the pheromone/receptor genes as well as the HD transcription factors. Orthology inference identified 1482 orthogroups exclusively found in F. floriforme, some of which were involved in carbohydrate transport and metabolism. Subsequent CAZyme repertoire characterization identified 267 and 247 enzymes for CBS6241 and CBS6242, respectively, the second highest number of CAZymes among the analyzed Tremellomycete species. In addition, F. floriforme contains five CAZymes absent in other species and several plant-cell-wall degrading CAZymes with the highest copy number in Tremellomycota, indicating the biotechnological potential of this species.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

Is selfing a reproductive assurance promoting polyploid establishment? Reduced fitness, leaky self‐incompatibility and lower inbreeding depression in neotetraploids

Premise Newly formed polyploids face significant obstacles to persistence and population establishment because of fitness costs of intercytotype mating. Selfing provides the opportunity to escape mate limitation, enabling production of new individuals and increasing the likelihood of fixation of new polyploid lineages. Still, association between self‐compatibility and polyploidy is not always clear. We compared self‐incompatibility and inbreeding depression in neotetraploids and their diploid progenitor to explore the direct effects of whole genome duplications on self‐incompatibility and the implications of ploidy‐driven changes for polyploid establishment. Methods Outcross and self‐pollinations were performed in diploids and synthetic neotetraploids of Jasione maritima var. maritima , and reproductive success was measured through fruit and seed production and seed germination. Self‐ and outcross offspring were grown under controlled conditions, and plant performance was measured through several fitness parameters. Results Neotetraploids showed an overall lower performance than diploids. Reproductive success was negatively affected by selfing in both cytotypes. However, greater variation in the expression of self‐incompatibility was observed in neotetraploids; additionally, developmental and physiological parameters were not affected by selfing on neotetraploids, with an overall similar fitness of outcrossed and selfed individuals, resulting in lower inbreeding depression indexes. Conclusions Neotetraploids might have benefited from selfing at initial stages after their formation. Genome duplications resulted in leaky self‐incompatibility, enabling the production of offspring under minority cytotype disadvantage with similar fitness as outcrossed offspring. Our results support theoretical assumptions that selfing might be important for neopolyploid establishment, although changes in self‐incompatibility might not be abrupt.

Siopa, Catarina↗

DOE OSTI2020

The role of mab‐3 in spermatogenesis and ontogenesis of pinewood nematode, Bursaphelenchus xylophilus

Abstract Background Bursaphelenchus xylophilus is one of the most destructive invasive species, causing extensive economic losses worldwide. The sex ratio of female to male of B. xylophilus plays an important role in the nematode infestation. However, little is known about the processes of its sex determination. The double sex/mab‐3‐related family of transcription factors are highly conserved in animals, playing crucial roles in sex determination, spermatogenesis and ontogenesis. We therefore investigated its orthologue, Bxy‐mab‐3 , in B. xylophilus . Results Bxy‐mab‐3 has two typical conserved DNA‐binding domains. It was observed in J2 (the second‐stage of juveniles), J3, J4 and male adults (specifically on the spicules), but not in eggs or female adults via mRNA in situ hybridization. RNA‐Seq indicated significantly higher expression in males. RNAi showed that the body size and sperm size of male adults were markedly smaller than those of the controls. Meanwhile, almost all the RNAi‐treated males failed to mate with the normal females, even 26.34% of interfered males did not produce sperm. However, RNAi of Bxy‐mab‐3 had no effect on the sex ratio of B. xylophilus . Conclusion Bxy‐mab‐3 is indispensable for spermatogenesis, ontogenesis and mating behavior. It is a typical sex‐determination gene with differential expression in males and females. However, knocking down Bxy‐mab‐3 expression could not alter the sex ratio as seen in other species. Our findings contribute towards a better understanding of the molecular events of Bxy‐mab‐3 in B. xylophilus , which provides promising hints for control of pine wilt disease by blocking ontogenesis and decreasing nematode fecundity.

Zhou, Lifeng↗

DOE OSTI2022

Solution characterization of the dynamic conjugative entry exclusion protein TraG

The R100 plasmid and the secretion system it encodes are representative of F-like conjugative type IV secretion systems for the transmission of mobile DNA elements in gram-negative bacteria, serving as a major contributor to the spread of antibiotic resistance in bacterial pathogens. The TraG protein of F-like systems consists of a membrane-bound N-terminal domain and a periplasmic C-terminal domain, denoted TraG*. TraG* is essential in preventing redundant DNA transfer through a process termed entry exclusion. In the donor cell, it interacts with TraN to facilitate mating pair stabilization; however, if a mating pore forms between bacteria with identical plasmids, TraG* interacts with its cognate TraS in the inner membrane of the recipient bacterium to prevent redundant donor–donor conjugation. Structural studies of TraG* from the R100 plasmid have revealed the presence of a dynamic region between the N- and C-terminal domains of TraG. Thermofluor, circular dichroism, collision-induced unfolding–mass spectrometry, and size exclusion chromatography linked to multiangle light scattering and small angle x-ray scattering experiments indicated an N-terminal truncation mutant displayed higher stability and less disordered content relative to full-length TraG*. The 45 N-terminal residues of TraG* are hypothesized to serve as part of a flexible linker between the two independently functioning domains.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2026

Data for Protoplast Fusion as a Strategy to Increase Ploidy in Rhodotorula toruloides for Strain Development

Rhodotorula toruloides is a red oleaginous yeast with growing commercial interest because of its hardiness and exceptional lipid production capacity. Because it is a basidiomycete yeast with a complex life cycle, many of the classical breeding methods used with ascomycetes are unavailable for strain improvement. However, we have been able to construct polyploid yeast by fusing protoplasts of parents with the same mating type. Fusing of Y-6985 (A2) and Y-48190 (A2), which had been transformed with complementary antibiotic markers, led to the recovery of two diploids and one triploid. The stability of the fusion yeasts was tested by plating them on non-selective medium after several growth cycles under antibiotics and then testing five colonies per strain for nuclear DNA contents using flow cytometry and standard cell cycle analysis: the triploid and one diploid were stable. Fusants inherited their mitochondria from a single parent, which was demonstrated using restriction fragment length polymorphism (RFLP) of mitochondrial DNA. The phenotypic properties of the parents and fusants were compared in glucose fed-batch bioreactor studies and cellulosic sugar batch cultures. The final lipid titers for the fed-batch cultures were 24.9–39.7 g/L with Y-6985 and the diploid and triploid performing the best and worst, respectively. The fusants demonstrated intermediate hardiness for growth on hydrolysate prepared with dilute-acid pretreated switchgrass and were outperformed by Y-48190. Unlike one of the haploid parents, the fusants grew in 70% v/v concentrated hydrolysate. However, they did not grow as fast as the other haploid. In this study, a modernized protoplast fusion method is resurrected a useful tool for strain development in this yeast, which is complementary with other available methods.

FOS: Biological sciences↗

DOE OSTI2022

A positive feedback loop involving the Spa2 SHD domain contributes to focal polarization

Focal polarization is necessary for finely arranged cell-cell interactions. The yeast mating projection, with its punctate polarisome, is a good model system for this process. We explored the critical role of the polarisome scaffold protein Spa2 during yeast mating with a hypothesis motivated by mathematical modeling and tested by in vivo experiments. Our simulations predicted that two positive feedback loops generate focal polarization, including a novel feedback pathway involving the N-terminal domain of Spa2. We characterized the latter using loss-of-function and gain-of-function mutants. The N-terminal region contains a Spa2 Homology Domain (SHD) which is conserved from yeast to humans, and when mutated largely reproduced the spa2Δ phenotype. Our work together with published data show that the SHD domain recruits Msb3/4 that stimulates Sec4-mediated transport of Bud6 to the polarisome. There, Bud6 activates Bni1-catalyzed actin cable formation, recruiting more Spa2 and completing the positive feedback loop. We demonstrate that disrupting this loop at any point results in morphological defects. Gain-of-function perturbations partially restored focal polarization in a spa2 loss-of-function mutant without restoring localization of upstream components, thus supporting the pathway order. Thus, we have collected data consistent with a novel positive feedback loop that contributes to focal polarization during pheromone-induced polarization in yeast.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2021

Developing Advanced Genetic and Synthetic Biology Tools for Improved Algae Productivity

Under the UCSD-led Productivity Enhanced Algae and ToolKits (PEAK) project we sought to develop tools to enable the production of valuable co-products, as well as strategies to decrease the cost of cultivation, with an intended outcome of enabling the economic production of algae-based biofuel. We have developed new genetic tools and high throughput selection methods for eukaryotic green algae and used them to express a high value recombinant protein; a growth factor known as Osteopontin (OPN). Recombinant OPN protein expression levels were improved through a newly developed rapid breeding and mutagenesis strain improvement method to generate a robust strain capable of growing in outdoors raceway conditions in brackish water that tolerated high pH and large temperature swings. We further applied the new genetic tools to express recombinant protein in a recently bioprospected strain with even more robust growth characteristics. In response to the COVID-19 pandemic we used our improved workflow to rapidly express, purify, and characterize a recombinant SARS-CoV-2 spike protein Receptor Binding Domain (RBD) and demonstrate that it functionally interacts with its cognate human host receptor ACE2. The newly identified extremophile strain Chlamydomonas sp (402), both mating type (mt+) and mating type (mt-), have been deposited in the Chlamydomonas Resource Center (https://www.chlamycollection.org/), making them available world-wide with no restrictions. In addition, all of genetic tools are also deposited at this site and are also available world-wide with no restrictions.

09 BIOMASS FUELS↗

DOE OSTI2022

An Updated Review of Hypotheses Regarding Bat Attraction to Wind Turbines

Patterns of bat activity and mortalities at wind energy facilities suggest that bats are attracted to wind turbines based on bat behavioral responses to wind turbines. For example, current monitoring efforts suggest that bat activity increases post-wind turbine construction, with bats making multiple passes near wind turbines. We separated the attraction hypothesis into five previously proposed explanations of bat interactions at or near wind turbines, including attraction based on noise, roost sites, foraging and water, mating behavior, and lights, and one new hypothesis regarding olfaction, and provide a state of the knowledge in 2022. Our review indicates that future research should prioritize attraction based on social behaviors, such as mating and scent-marking, as this aspect of the attraction hypothesis has many postulates and remains the most unclear. Relatively more data regarding attraction to wind turbines based on lighting and noise emission exist, and these data indicate that these are unlikely attractants. Analyzing attraction at the species-level should be prioritized because of differences in foraging, flight, and social behavior among bat species. Lastly, research assessing bat attraction at various scales, such as the turbine or facility scale, is lacking, which could provide important insights for both wind turbine siting decisions and bat mortality minimization strategies. Identifying the causes of bat interactions with wind turbines is critical for developing effective impact minimization strategies.

17 WIND ENERGY↗

DOE OSTI2026

Species-specific acoustic responses by bats to ultrasonic stimuli used for reducing bat-wind turbine interactions

An unintended consequence of wind energy generation is bat fatalities caused by wind turbine blade strikes. One potential approach to reduce collision risk is to use ultrasound to create an uncomfortable or disorienting airspace around wind turbine blades. Ultrasonic deterrents (UDs) have produced mixed results in experimental field studies at commercial wind energy facilities, with effectiveness varying by species and location. It is possible that some species can alter their normal echolocation characteristics to counter the signal of UDs. Our broad objective was to maximize the effectiveness of a UD by comparing changes in echolocation characteristics during three UD frequency emissions among species, between seasons, and between sex. We hypothesized that UD emissions with frequencies most similar to each species’ echolocation characteristics would be more likely to alter the bats’ echolocation, and bat responses would vary between seasons and sex for each species. We released wild-captured bats into a 60 m × 10 m × 4.4 m (length × width × height) flight cage located in San Marcos, Texas, USA, from July to October 2020 and March to May 2021 and monitored echolocation frequencies with ultrasonic microphones. We conducted trials on Brazilian free-tailed bats ( Tadarida brasiliensis ; n = 54), cave myotis ( Myotis velifer ; n = 44), red bats ( Lasiurus blossevilli , Lasiurus borealis ; n = 41), evening bats ( Nycticeius humeralis ; n = 32), and tricolored bats ( Perimyotis subflavus ; n = 8). We found that species with high-frequency echolocation calls altered their echolocation signatures more commonly during high-frequency UD emissions, whereas low-frequency bats altered their echolocation signatures more commonly during low-frequency UD emissions. Additionally, echolocation responses varied between seasons and sexes for several species. Variations in responses may be dependent on species migratory status, differences in mating behavior and mating season, hormonal differences between sexes and seasons, and/or constraints on echolocation adaptability. Our results offer insights into the variable effectiveness of UDs at reducing bat fatalities at wind turbines and provide information for potential adjustments to UDs for improved success.

17 WIND ENERGY↗

NASA NTRS1968

Design concept for nonarcing electrical connector

Connector plug automatically minimizes arcing during mating and demating. This plug uses a high-resistivity outer sheath as an extension to the regular pin contact. It is used in atmospheres containing explosive gases, and reduces erosion at the contact surfaces where mating and demating are performed frequently.

Holmen, R. E.↗

NASA NTRS1972

Relative biological effectiveness of fast neutrons compared with X-rays: Prenatal mortality in the mouse

The effects of fission neutrons and of X-rays on the mouse zygote are discussed. Seven-week-old virgin mice were allowed a 12-hour mating opportunity beginning at 7:00 P.M. Between 1:30 and 4:00 P.M., except where indicated otherwise, the females which had mated (vaginal plug) during the night were either irradiated or sham-irradiated. At the time of irradiation the zygotes were in a pronuclear stage. Sixteen days later the mice were killed and the uteri dissected. The number of dead embryos, live embryos, and gross anomalies were determined. Dead embryos were classified as to stage of development.

Friedberg, W.↗