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This article is the second of a three-part series in which we present the results of a study exploring concepts for improving communications and tracking capabilities of deep space SmallSats. In Part I, we discussed SmallSat direct-to-earth links and SmallSat communications equipment, and provided recommendations for future work. In Part II, we focus on SmallSat navigation options, Disruption Tolerant Networking (DTN), proximity links, and the use of the communication link for science observations, and we provide recommendations for future work. We have examined both radio and optical navigation options, and considered autonomous and semiautonomous navigation to reduce operational costs for planetary SmallSats. We note that communication link resilience to delay and disruption enhances spacecraft autonomy; therefore, we have provided a discussion of DTN to indicate that using DTN allows for automated data transmission and recovery, therefore, reducing manual operations. SmallSats in deep space may utilize a relay spacecraft for communications with earth or function as a relay for landed and in-orbit assets. We present a detailed examination of relay proximity links and networks where we address both proximity hardware and networking scenarios. The proximity link features that we examine include the network architecture and its relationship to DTN, proximity radios and antennas, communications link performance, and proximity navigation. The use of the communication link for science has been practiced by primary missions in deep space scenarios. (Two examples of past planetary radio science experiments can be found in the following: https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/radio-science-subsystem/ and https://www.boulder.swri.edu/pkb/ssr/ssr-rex.pdf) Likewise, SmallSats can offer their radio links for radio science investigations. This article provides a brief introduction to radio science and presents the prerequisite features necessary for radio science observations by SmallSats. We conclude with nine recommendations based on the findings of the study. These recommendations are guidelines on the design, implementation, and operation of deep space SmallSat communication links. The adoption of some or all of the guidelines should result in an enhanced communication and tracking capability for the deep space SmallSat missions.

The objective of the study was to quantify the effect of cage material (titanium-alloy vs. polyetheretherketone or PEEK) and design (porous vs. solid) on subsidence and osseointegration.Three lateral cages (solid PEEK, solid titanium, and 3-dimension-printed porous titanium cages) were evaluated for cage stiffness, subsidence compression stiffness, and dynamic subsidence displacement under simulated postoperative spine loading. Dowel-shaped implants made of grit-blasted solid titanium alloy (solid titanium) and porous titanium were fabricated using commercially available processes. Samples were processed for mechanical push-out testing and polymethylmethacrylate histology following an established ovine bone implantation model.The solid titanium cage exhibited the greatest stiffness (57.1 ± 0.6 kN/mm), followed by the porous titanium cage (40.4 ± 0.3 kN/mm) and the solid PEEK cage (37.1 ± 1.2 kN/mm). In the clinically relevant dynamic subsidence, the porous titanium cage showed the least amount of subsidence displacement (0.195 ± 0.012 mm), significantly less than that of the solid PEEK cage (0.328 ± 0.020 mm) and the solid titanium cage (0.538 ± 0.027 mm). Bony on-growth was noted histologically on all implant materials; however, only the porous titanium supported bony ingrowth with marked quantities of bone formed within the interconnected pores through 12 weeks. Functional differences in osseointegration were noted between groups during push-out testing. The porous titanium showed the highest maximum shear stress at 12 weeks and was the only group that demonstrated significant improvement (4-12 weeks).The choice of material and design is critical to cage mechanical and biological performances. A porous titanium cage can reduce subsidence risk and generate biological stability through bone on-growth and ingrowth.

The ability of particulate bioactive glass to function as an effective bone graft material is directly related to its in vivo dissolution, ion release, and interparticle spacing (area associated with bone in-growth). A spherical shape represents an optimal geometry to control bioactive glass bone formation properties. Spherical particles were fabricated from 45S5 bioactive glass with unimodal (90-180, 180-355, and 355-500 μm) and bimodal size ranges (180-355/355-500 and 90-180/355-500 μm). Particles were formed into bone graft putties and compared to a commercially available product composed of irregular 45S5 bioactive glass particles (32-710 μm). Scanning electron microscopy characterization of spherical particles showed a relatively uniform sphere shape and smooth surfaces. Irregular particles were characterized by random shapes with flat surfaces and sharp edges. X-ray fluorescence and X-ray diffraction indicated that the spheroidization process maintained the properties of 45S5 bioactive glass. Cross-sectional micro-computed tomography imaging of the putty samples demonstrated that smaller spheres and irregular particles resulted denser packing patterns compared to the larger spheres. Isolated particles were immersed in simulated body fluid for 14 days to measure silicon ion release and bioactivity. Inductively coupled plasma spectroscopy showed faster ion release from smaller particles due to increased surface area. Bioactivity characterization of 14-day simulated body fluid exposed particle surfaces showed the presence of a hydroxycarbanoapatite mineral layer (characteristic of 45S5 bioactive glass) on all bioactive glass particles. Results demonstrated that spherical particles maintained the properties of the starting 45S5 bioactive glass, and that particle shape and size directly affected short-term glass dissolution, ion release, and interparticle spacing.

Mouse haematopoietic stem cells (HSCs) first emerge at embryonic day 10.5 (E10.5), on the ventral surface of the dorsal aorta, by endothelial-to-haematopoietic transition. We investigated whether mesenchymal stem cells, which provide an essential niche for long-term HSCs (LT-HSCs) in the bone marrow, reside in the aorta-gonad-mesonephros and contribute to the development of the dorsal aorta and endothelial-to-haematopoietic transition. Here we show that mesoderm-derived PDGFRA

As treatment for prostate cancer matures with many options for local, regional and systemic care, patients are living longer. Coupled with aggressive therapy for oligometastatic disease and improvements in multiple treatment pathways including radiopharmacy, both disease-free and overall survival are improving for many patients. Success can also bring new challenges that require new thought processes for care. In this paper we present two patients who had undergone previous radiation therapy for adenocarcinoma of the prostate with curative intent who required consideration for re-irradiation each more than 15 years away from primary management.

Ring expansion testing is one of the three accepted methods in API 5L for the measurement of yield strength for line pipe. The other two are flattened-strap tensile testing and round-bar tensile testing. A novel-concept ring expansion test machine has recently been commissioned which uses hydraulic pressure to clamp the top and bottom pressure-reacting plates rather than a traditional bolting arrangement. The benefit of hydraulic clamping is vastly reduced set-up times. This paper describes the design approach and the pitfalls that were overcome in commissioning the ring expansion test unit. Expansion measurements are taken using two different methods: a chain extensometer and an LVDT with a band wrapping the circumference of the pipe. Both approaches are used simultaneously to generate and compare two stress-strain curves for one pressure test. In addition, a 3-Point contact approach is developed to determine the hoop strain during pipe expansion. The 3-point contact approach is an attempt to infer the full hoop expansion behavior by measuring the radius change over a segment of the circumference. The device has two rollers which contact the pipe surface while a dial indicator midway between measures the radius change. As the pipe expands, the rollers maintain contact with the pipe surface while the dial indicator records the change in radius. Tests are performed on HFI, SAWL, and SAWH pipes ranging in outer diameter from 20-inch (508 mm) to 48-inch (1219 mm) and wall thicknesses from 0.375-inch (9.5 mm) to 0.969-inch (24.4 mm). The differences in the stress-strain behavior of these pipe forms are described and related to the residual-stress profiles generated by their respective manufacturing operations. The comparison to flattened-strap and round-bar tensile results are presented in a companion paper. The results of the 3-Point contact approach show that the radius change during early stages of expansion are not uniform around the pipe circumference and different patterns are observed in the HFI, SAWL, and SAWH pipe forms.

Tensile properties of API 5L large diameter pipes are typically determined with the use of full thickness flattened strap samples extracted in the transverse direction with respect to the longitudinal pipe axis (TPA) [1, 2, 3, 4]. It has been well established that the process of sample flattening has a significant influence on determination of the yield strength of the pipe [5, 6]. The flattening process is sensitive to a number of variables such as method of flattening, equipment used, number/sequence of strokes, and operators conducting the flattening. As a result, issues with repeatability are frequently encountered and despite several efforts, the industry lacks any type of official standard for universal use. Historically, the industry has been focused on ensuring that the actual strength of pipes was safely higher than the specified minimum. Recently, there has been interest to also establish an upper limit on pipe strength particularly in the longitudinal direction with respect to the pipe axis (LPA) in order to avoid under matching between pipe and girth weld properties. These new requirements create the need for enhanced process control to minimize the variation due to flattening. Samples obtained from longitudinally welded (SAWL) and helically welded (SAWH) seam Grade X70M line pipe of various nominal wall thickness to diameter (t/D) ratios were flattened using different procedures, measured for curvature, and tensile tested, all in controlled laboratory environments with minimized repeatability variation. Special attention was given to the definition and measurement of different types of curvatures observed through the range of different t/D ratios and effort was made to assess criteria for curvature measurement prior to testing. Additionally, non-flattened specimens were tensile tested using round bar and full ring expansion test methods, and a comparison between the results obtained from both flattened and non-flattened specimen methods was made. The sample transverse yield strength results confirmed the expected variation between samples flattened by different methods. In addition, a much greater variation was observed when comparing the yield strength results between flattened and non-flattened samples. Considerations of extending the use of non-flattened specimens as a production test and benefits or limitations associated with such practice are discussed.

In this paper, we discuss a concept for a Radio Frequency (RF) Ka band communications payload that is robotically assembled and serviced in space using a servicing vehicle such as the Robotic Servicing of Geosynchronous Satellites (RSGS) vehicle being developed by the Defense Advance Research Projects Agency (DARPA). Our work focuses on how to modularize a representative Ka band communications payload into discrete modules that are hosted on a persistent platform. In our concept, each module consists of a primary aperture and the associated RF and electronics required to serve a particular coverage area or type. These modules are notionally packaged in a form factor capable of launching as a secondary payload via an EELV Secondary Payload Adapter (ESPA) ring or a Payload Orbital Delivery System (PODS) module. The overall payload consists of an earth coverage module, regional coverage modules, high gain regional coverage modules, and a host interface unit (HIU). We discuss the notional capabilities and requirements of each module. We present two different architecture concepts corresponding to two different persistent platform concepts. In one concept, the persistent platform is made up of small, independent spacecraft that are connected together with structural members with communication channels. The payload modules are hosted on the individual spacecraft. In the second approach, the platform consists of a large central spacecraft with a structural truss that has power, communication and thermal loops. The payload modules are hosted on the truss through standard interfaces. We present aspects of the mission concept on how the payload may be modularized, launched (as secondary launch elements), acquired by the RSGS vehicle in space and assembled on to the persistent platform. We discuss the robotics aspects of assembly and servicing of the payload modules. A key aspect of this concept is the serviceability of the payload. Central to the modular and discrete payload design is an intent to refurbish the payload incrementally as technology evolves or the components fail. Existing geosynchronous communication satellites are designed and built as monolithic spacecraft which makes any servicing beyond refueling fairly complicated. This makes it hard to take advantage of the post launch evolution in technology, particularly in the electronics elements. Our concept is aimed at modularizing the payload such that the modules, particularly the electronics elements, can be easily serviced using the RSGS vehicle. Our concept attempts to take advantage of the long service life of high reliability system components in the core satellite bus while allowing rapid expansion and upgrading of the communications payload through the addition and replacement of individual payload modules.

The importance of autonomy in robotics is magnified when the robots need to be deployed and operated in areas that are too dangerous or not accessible for humans, ranging from disaster areas (to assist in emergency situations) to Mars exploration (to uncover the mystery of our neighboring planet). The DARPA Subterranean (SubT) Challenge presents a great opportunity and a formidable robotics challenge to foster such technological advancement for operations in extreme and underground environments. Robot teams are expected to rapidly map, navigate, and search underground environments including natural cave networks, tunnel systems, and urban underground infrastructure. Subterranean environments pose significant challenges for manned and unmanned operations due to limited situational awareness. In the first phase of the DARPA Subterranean Challenge (held in August 2019; targeting underground tunnels and mines), Team CoSTAR, led by NASA JPL, placed second among 11 teams across the world, accurately mapping several kilometers of two mine systems and localizing 17 target objects in the course of four one-hour missions. While the main goal of Team CoSTAR at the end of this three-year challenge (August 2021) is a fully autonomous robotic solution, this paper describes Team CoSTAR's results in the first phase of the challenge (August 2019), focusing on supervised autonomy of a multi-robot team under severe communication constraints. This paper also presents the design and initial results obtained from field test campaigns conducted in various tunnel-like environments, leading to the competition.

Funder: University of Oxford, This article examines the institution of celebrity within academia. Academic celebrity has parallels with the celebrity seen in the wider world, though it is born of conditions unique to the fields of higher education and research and exhibits its own special characteristics. Whilst the scholarly prominence of academics can be based on more or less impersonal measures, especially citation statistics, academic celebrity, like popular celebrity, has emotional and subjective dimensions that call for non-subjective analysis. That challenge is met in this article by pointing to the cultural and institutional underpinnings of the phenomenon. In outlining some of academic celebrity’s defining features, we explore the critical difference between scholarly prominence, which is based on the perception of an academic’s excellence within their field, and celebrity, which incorporates adulation from colleagues and students. In reviewing the literature on the subject, we find models elaborating the ways in which modernity, in contrast to Elias’s court society (Rojek), or the world of aristocratic artistic patronage (Bourdieu), creates the conditions for the adulation of celebrities and the emergence of celebrity as an institution. We also find views critical of both the vulgarising effect of celebrity on literary and artistic taste (Coser), and its self-perpetuating character (Boorstin, Merton). Finally, we examine aspects of academic celebrity’s institutionalisation: the dynamic that drives the creation of new fields of specialisation within which academic celebrity is embedded, and the ‘managerial university’, which is said to generate and sustain it (Moran).

This paper discusses recent activities at JPL that are focused on the development of wireless communications for data path connectivity between instruments and subsystems within the confines of a single spacecraft. Anticipated benefits of intra-spacecraft wireless links include reduction of cable mass, improved flexibility in spacecraft design or modifications and increased efficiencies during integration and test. This paper describes the framework for this effort, plans for retiring key risks and progress to date. Three of the primary risks addressed under this effort are communications link reliability, scalability and electromagnetic compatibility. In this paper, we will discuss analysis and test methods used to investigate each of these areas. In addition, we will describe a number of use cases for both operational and test applications that are under current investigation and development.

IMPORTANCE: This study characterizes and compares common surgical manipulations’ effects on septal cartilage to understand their implications for rhinoplasty outcomes based on cell viability and cartilage health. OBJECTIVE: To illustrate distinct differences in the impact of various surgical manipulations on septal cartilage in an in vitro septal cartilage model. A secondary objective is to better understand the chondrocyte’s response to injury as well as how alterations in the extracellular matrix correspond to chondrocyte viability. DESIGN, SETTING, AND PARTICIPANTS: In this bench-top in vitro porcine model using juvenile bovine septal cartilage from bovine snouts, easily obtainable septal cartilage was used to generate large numbers of homogenous cartilage specimens. Quantitative outcomes at early and late time points were cell viability, cell stress, matrix loss, and qualitative assessment through histologic examination. The study was performed at a single academic tertiary care research hospital. INTERVENTIONS: Four common surgical manipulations were contrasted with a control group: crushed cartilage, scored cartilage, diced cartilage, and shaved cartilage. MAIN OUTCOMES AND MEASURES: Following the manipulation of the cartilage, the quantitative outcomes were glycosaminoglycan release to the media, lactate dehydrogenase release to the media, and cell death analysis through apoptosis staining. The qualitative outcomes were histologic staining of the manipulated cartilage with safranin-O/fast green stain to identify proteoglycan loss. RESULTS: The crushing followed by shaving manipulations were the most damaging as indicated by increased levels of lactate dehydrogenase release, glycosaminoglycans loss, and cell death. Matrix loss did not increase until after 48 hours postinjury. Furthermore, chondrocyte death was seen early after injury and accelerated to the late time point, day 9, in all manipulations. Conversely, cell stress was found to be greater at 48 hours postinjury, which then declined to the late time point, day 9. CONCLUSIONS AND RELEVANCE: The crushing manipulation followed by shaving and then dicing were the most destructive methods of cartilage manipulation relative to control specimens. Collectively, these outcomes demonstrate the range of injury which occurs with all septal cartilage manipulations and can inform rhinoplasty practice to use the least damaging effective surgical manipulation to obtain the desired outcome. LEVEL OF EVIDENCE: NA.

Lava tubes are thought to exist on Mars and on the Moon, and are of special interest for science objectives and human habitability. The communications environment in such a cave is important for exploration. This paper explores the use of the shooting and bouncing rays (SBR) approximation to modeling the electromagnetics environment in a basalt rock lava tube with an obstruction, such as a cave-in. The cave, which has smooth walls, widens until the obstruction occurs, and then narrows. There is no line-of-sight communications path. A cave length of 100 meters is modeled. Existing knowledge of tunnel communications and the ANSYS Savant tool are leveraged in order to provide results for the cave geometry. A number of observations are offered in the following areas based on indications obtained from lava tube modeling: (1) Enhanced signals are observed. This is the degree to which the cave walls can create an amplification of the received signal and assist communications by reflecting the incident and re-scattered signals. Communications behind the obstacle is possible. (2) Spatial signal fading was observed, hinting at geometric effects or that scattered signals can combine destructively. Deep fades occur but appear to be rare. (3) Diminished signal strength occurs at the boundaries. Robotic exploration may take place close to the cave floor or walls. Indications from simulation for signal strengths close to the cave floor and walls are examined. (4) Frequency-selective fading can occur. The time-delay spread is discussed. The simulation results include an evaluation of IEEE 802.11 WiFi at 2.4 GHz using a freestanding electric cross dipole antenna and transmitted signal powers from 10mW to 100mW. Receive data rates are derived at locations throughout the cave and are provided to the degree that the cave geometry and electromagnetics approximations hold. These are only estimates of actual data rates subject to the approximations that were applied. Simplifications and adaptations of the WiFi waveform are discussed as part of a power trade.