Ribosome biogenesis: Stripping for AAAction?

AbstractRibosomal subunits are assembled in the nucleolus before being transported to the cytoplasm. Recent work has identified both a protein that may play a key role in restructuring the large, 60S subunit prior to transport and factors that facilitate transport itsel

Neuromuscular Control System for Small-Unmanned Aircraft Systems

The use of electromyography devices to collect neuromuscular-activated user input into control commands is an emerging market. With the number of internet-connected devices approaching an estimated fifty billion by the year 2020, the need to develop a more natural human-machine interface arises. This paper discusses the development of a gesture-based control system with the integration of a heart rate sensing safety module as a means of controlling a small unmanned aircraft system (sUAS) while monitoring the ability of an operator to safely control the device. Heart rate data from five subjects, three male, two female, age range of 20 – 30 and of various body-mass-index, was collected and analyzed to determine a safe range in beats-per-minute for the operator to be considered unimpaired. The system was found to be successful in executing gesture-based commands to control a sUAS while the heart rate safety module remains a proof-of-concept showing its ability to transmit operator data while allowing the system to process the data and react accordingly

Dual-Modality Haptic Feedback Improves Dexterous Task Execution with Virtual EMG-Controlled Gripper

Upper-extremity amputees who use myoelectric prostheses currently lack the haptic sensory information needed to perform dexterous activities of daily living. While considerable research has focused on restoring this haptic information, these approaches often rely on single-modality feedback schemes which are necessary but insufficient for the feedforward and feedback control strategies employed by the central nervous system. Multi-modality feedback approaches have been gaining attention in several application domains, however, the utility for myoelectric prosthesis use remains unclear. In this study, we investigated the utility of dual-modality haptic feedback in a virtual EMG-controlled grasp-and-hold task with a brittle object and variable load force. We recruited N=20 non-amputee participants to perform the task in four conditions: no feedback, vibration feedback of incipient slip, squeezing feedback of grip force, and dual (vibration + squeezing) feedback of incipient slip and grip force. Results suggest that receiving any feedback is better than receiving none, however, dual-modality feedback is far superior to either single-modality feedback approach in terms of preventing the object from breaking or dropping, even after it started slipping. Control with dual-modality feedback was also seen as more intuitive than with either of the single-modality feedback approaches

In Vitro Interactions of Extracellular Histones with LDL Suggest a Potential Pro-Atherogenic Role

BACKGROUND: Nuclear histones have previously been shown to aggregate LDL in vitro, suggestive of a possible pro-atherogenic role. Recent studies indicate that histones are released during acute inflammation, and therefore might interact with circulating lipoproteins in vivo. In view of the associative link between inflammation and cardiovascular disease, the behaviour of histones was investigated using in vitro models of LDL retention and foam cell formation. METHODOLOGY/PRINCIPAL FINDINGS: Heparin agarose beads were used as a model of a matrix rich in sulphated glycosaminoglycans, to which histones bind strongly. Histone-modified beads were observed to pull down more LDL from solution than untreated beads, indicating that histones can function as bridging molecules, enhancing LDL retention. Furthermore, addition of heparin inhibited histone-induced aggregation of LDL. To model foam cell formation, murine RAW 264.7 macrophages were incubated for 24 h in the presence of LDL, histones, LDL plus histones or vehicle control. Cells incubated with LDL in the presence of histones accumulated significantly more intracellular lipid than with LDL or histone alone. CONCLUSIONS/SIGNIFICANCE: These results are consistent with a potential pro-atherogenic role for extracellular histones, which should be investigated further

End of Life Disposal for Three Libration Point Missions through Manipulation of the Jacobi Constant and Zero Velocity Curves

The aim of this investigation is to determine the feasibility of mission disposal by inserting the spacecraft into a heliocentric orbit along the unstable manifold and then manipulating the Jacobi constant to prevent the spacecraft from returning to the Earth-Moon system. This investigation focuses around L1 orbits representative of ACE, WIND, and SOHO. It will model the impulsive delta-V necessary to close the zero velocity curves after escape through the L1 gateway in the circular restricted three body model and also include full ephemeris force models and higher fidelity finite maneuver models for the three spacecraft

Applying Dynamical Systems Theory to Optimize Libration Point Orbit Stationkeeping Maneuvers for WIND

NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using dynamical systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the optimized maneuver method into operations is discussed and results are presented for the first two optimized stationkeeping maneuvers executed by WIND

A blended-learning approach to supporting students in organic chemistry: Methodology and outcomes

In the recent past, we recognised the need to support students in developing an effective approach to learning mechanistic organic chemistry, as many were finding it challenging to identify appropriate strategies to tackle this key area of their studies. A set of supporting resources in the form of videos and animations to reinforce understanding of the basic principles behind mechanisms were designed to improve skill levels and confidence. An online approach to delivery and engagement was combined with selfassessment to produce a package that was delivered as a vacation activity which was not credit bearing. The outcomes of the initial experiment included excellent levels of uptake by students, with many expressing greater confidence in their ability to understand and apply their mechanistic knowledge. Since the first iteration of this project a thorough qualitative evaluation has been undertaken. The clear message is that students found these resources valuable in their learning. This paper will describe the methodology and the outcomes from both the student and tutor perspective

An analysis of single clutch paternity in the burrower bug Sehirus cinctus using microsatellites

Recent studies of the burrower bug, Sehirus cinctus, have examined the genetic basis of parental care. An understanding of the burrower bug mating system, and the subsequent pattern of offspring relatedness that this system generates, is critical to further interpret genetic data. To this end, we developed three consistently amplifiable highly polymorphic microsatellite loci and used them to determine genotypic patterns at the level of both the population and the single clutch. We found that all clutches were sired by single males. Further, we find no evidence for inbreeding. We hypothesize that single paternity within a clutch may play an important role in reducing the potential for sibling rivalry, by increasing the relatedness among clutchmates