ESA F-Class Comet Interceptor: Trajectory design to intercept a yet-to-be-discovered comet

Comet Interceptor (Comet-I) was selected in June 2019 as the first ESA F-Class mission. In 2029+, Comet-I will hitch a ride to a Sun-Earth L2 quasi-halo orbit, as a co-passenger of ESA's M4 ARIEL mission. It will then remain idle at the L2 point until the right departure conditions are met to intercept a yet-to-be-discovered long period comet (or interstellar body). The fact that Comet-I target is thus unidentified becomes a key aspect of the trajectory and mission design. The paper first analyses the long period comet population and concludes that 2 to 3 feasible targets a year should be expected. Yet, Comet-I will only be able to access some of these, depending mostly on the angular distance between the Earth and the closest nodal point to the Earth's orbit radius. A preliminary analysis of the transfer trajectories has been performed to assess the trade-off between the accessible region and the transfer time for a given spacecraft design, including a fully chemical, a fully electric and a hybrid propulsion system. The different Earth escape options also play a paramount role to enhance Comet-I capability to reach possible long period comet targets. Particularly, Earth-leading intercept configurations have the potential to benefit the most from lunar swing-by departures. Finally, a preliminary Monte Carlo analysis shows that Comet-I has a 95–99% likelihood of successfully visit a pristine newly-discovered long period comet in less than 6 years of mission timespan

Long Term Space Program Scheduling and System Design Optimization

The human planetary exploration goal asks for both a strong technology development and a great scientific knowledge enhancement that can be achieved only through a rational and well tuned sequence of different highly related missions, from demonstrators up to scientific probes, in the framework of a limited resources scenario. Therefore the programmatic division has to face the hard task of producing a long term planning deeply connected with the technical design of each unit belonging to a multi-missions scenario. The paper suggests a possible tool to solve the long term space missions planning problem by working on the single mission preliminary sizing, while taking into account the complex constraint net, both in the design and temporal domains. Thanks to the proposed multi-objective optimisation the engineers are given a pruned and ranked solution space, to work on to refine the programmatic. The Evolutionary Algorithms have been selected to deal with mixed domains and get the globally optimal solution set on the time and in design alternatives search space. Appropriate preliminary models are proposed to deal with the criteria vector elements here assumed to be the most relevant for the problem. The architecture has been tested on the NASA Apollo program scenario. The obtained results are consistent with the real program and possible discrepancies helped better tuning the tool. Simulations for ongoing exploration scenarios, such as the ESA Aurora, are offered to highlight the benefits of the tool in identifying a set of optimal, preliminary plans. A critical discussion is also offered

Double-negative (CD27−IgD−) B cells are expanded in NSCLC and inversely correlate with affinity-matured B cell populations

Background: The presence of B cells in early stage non-small cell lung cancer (NSCLC) is associated with longer survival, however, the role these cells play in the generation and maintenance of anti-tumor immunity is unclear. B cells differentiate into a variety of subsets with differing characteristics and functions. To date, there is limited information on the specific B cell subsets found within NSCLC. To better understand the composition of the B cell populations found in NSCLC we have begun characterizing B cells in lung tumors and have detected a population of B cells that are CD79A(+)CD27(-)IgD(-). These CD27(-)IgD(-)(double-negative) B cells have previously been characterized as unconventional memory B cells and have been detected in some autoimmune diseases and in the elderly population but have not been detected previously in tumor tissue. Methods: A total of 15 fresh untreated NSCLC tumors and 15 matched adjacent lung control tissues were dissociated and analyzed by intracellular flow cytometry to detect the B cell-related markers CD79A, CD27 and IgD. All CD79A(+) B cells subsets were classified as either naive (CD27(-)IgD(+)), affinity-matured (CD27(+)IgD(-)), early memory/germinal center cells (CD27(+)IgD(+)) or double-negative B cells (CD27(-)IgD(-)). Association of double-negative B cells with clinical data including gender, age, smoking status, tumor diagnosis and pathologic differentiation status were also examined using the logistic regression analysis for age and student's t-test for all other variables. Associations with other B cell subpopulations were examined using Spearman's rank correlation. Results: We observed that double-negative B cells were frequently abundant in lung tumors compared to normal adjacent controls (13 out of 15 cases), and in some cases made up a substantial proportion of the total B cell compartment. The presence of double-negative cells was also found to be inversely related to the presence of affinity-matured B cells within the tumor, Spearman's coefficient of -0.76. Conclusions: This study is the first to observe the presence of CD27(-)IgD(-)double-negative B cells in human NSCLC and that this population is inversely correlated with traditional affinity-matured B cell populations.National Cancer Institute [R01 CA129688, R01 CA129688-03S1, T32 CA09213, P30CA023074]; Geographic Management of Cancer Health Disparities Program (GMaP) Region 3, an initiative of the National Cancer Institute's Center to Reduce Cancer Health DisparitiesOpen access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

RC-SIM: Radiocomm Signals for Retrieval of Planetary Geophysical Parameters

The RC-SIM project aimed at the analysis of existing and new techniques for the exploitation of radio-communication signals from interplanetary probes for remote sensing of the surface and other geophysical parameters of planets and moons. Main objectives of the project have been to investigate the physical parameters which can be obtained from the use, as a remote sensing instrument, of the radio-communication systems on-board interplanetary probes; to analyse the added value provided by this approach compared to other types of instruments also supplying surface and other geophysical parameters; to develop a prototype simulator generating quantitative results of the different aspects involved in the radio communication link. After reviewing the previous and foreseen experiments on this field and the state-of-the-art of radio-communication systems, three target scenarios were considered: * Titan scenario, defining an orbiter around Titan and a balloon overflying its surface in different configurations for the realization of bistatic radar experiments to retrieve the dielectric constant and the root-mean-square (r.m.s.) surface slope. * Martian lander, to determine the Martian rotational state by using the Radio Frequencies (RF) signal coming from a lander on Mars to an Earth station. * Moon interferometric mission: this scenario involves a network of 3-4 widely spaced landers on the Moon and aims to accurate determination (to 0.2 mm) of lunar tides and librations. The most relevant models selected to simulate these scenarios have been: accurate Mars and Moon rotational state models; Titan surface model of interaction and reflection of RF signal; error models (atmospheric, solar plasma, transponder ageing \u2026); retrieval models. The simulator has been developed according to pre-selected scientific requirements that may come from future planetary missions to assess the potential benefits of the use of telecom links for geophysical investigation. The results show that state-of-the-art architecture of radio-communication systems may provide significant improvements in the knowledge of several geophysical parameters. The flexible simulator setup allows analysing different configurations and models, as well as performing sensitivity analyses in future missions\u2019 context

Randomized Crossover Trial Evaluating Detoxification of Tobacco Carcinogens by Broccoli Seed and Sprout Extract in Current Smokers

Consumption of cruciferous vegetables, rich in the isothiocyanate glucoraphanin, is associated with reduced risk of tobacco-related cancers. Sulforaphane, released by hydrolysis of glucoraphanin, potently induces cytoprotective phase II enzymes. Sulforaphane decreased the incidence of oral cancer in the 4NQO carcinogenesis model. In residents of Qidong, China, broccoli seed and sprout extracts (BSSE) increased detoxification of air pollutants benzene and acrolein, also found in tobacco smoke. This randomized, crossover trial evaluated detoxification of tobacco carcinogens by the BSSE Avmacol® in otherwise healthy smokers. Participants were treated for 2 weeks with both low and higher-dose BSSE (148 µmol vs. 296 µmol of glucoraphanin daily), separated by a 2-week washout, with randomization to low-high vs. high-low sequence. The primary endpoint was detoxification of benzene, measured by urinary excretion of its mercapturic acid, SPMA. Secondary endpoints included bioavailability, detoxification of acrolein and crotonaldehyde, modulation by GST genotype, and toxicity. Forty-nine participants enrolled, including 26 (53%) females with median use of 20 cigarettes/day. Low and higher-dose BSSE showed a mean bioavailability of 11% and 10%, respectively. Higher-dose BSSE significantly upregulated urinary excretion of the mercapturic acids of benzene (p = 0.04), acrolein (p < 0.01), and crotonaldehyde (p = 0.02), independent of GST genotype. Retention and compliance were high resulting in early study completion. In conclusion, BSSE significantly upregulated detoxification of the tobacco carcinogens benzene, acrolein, and crotonaldehyde in current tobacco smokers. © 2022, MDPI. All rights reserved.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]