Hazardous near Earth asteroid mitigation campaign planning based on uncertain information on fundamental asteroid characteristics

Given a limited warning time, an asteroid impact mitigation campaign would hinge on uncertainty-based information consisting of remote observational data of the identified Earth-threatening object, general knowledge of near-Earth asteroids (NEAs), and engineering judgment. Due to these ambiguities, the campaign credibility could be profoundly compromised. It is therefore imperative to comprehensively evaluate the inherent uncertainty in deflection and plan the campaign accordingly to ensure successful mitigation. This research demonstrates dual-deflection mitigation campaigns consisting of primary (instantaneous/quasi-instantaneous) and secondary (slow-push) deflection missions, where both deflection efficiency and campaign credibility are taken into account. The results of the dual-deflection campaign analysis show that there are trade-offs between the competing aspects: the launch cost, mission duration, deflection distance, and the confidence in successful deflection. The design approach is found to be useful for multi-deflection campaign planning, allowing us to select the best possible combination of missions from a catalogue of campaign options, without compromising the campaign credibility

Altruism in medical education: assessing attitudes of hospital in-patients towards face-to-face contact with medical students during the COVID-19 pandemic

Abstract Background Limited research indicated patients were largely amenable to seeing medical students pre-pandemic. However, the COVID-19 pandemic has highlighted the potential risk of nosocomial transmission and harm to patients from students. Patient opinions regarding these risks remain unexplored, which impacts elicitation of informed consent. We aim to identify these, and explore whether reflection on the risks and benefits of direct student interaction influenced patients’ attitudes. For guidance, we further explored measures to reduce perceived infection risk. Method We designed an original questionnaire for a cross-sectional study, completed by 200 inpatients from 25 wards between 18/02 and 16/03/2022 at Derriford Hospital, Plymouth. Patients in intensive care, with active COVID-19 infection or unable to comprehend the study information were excluded. The responses of a guardian were recorded for inpatients under 16. 17 questions were included - the initial question, reporting willingness to talk with and be examined by students, was repeated following nine questions exploring risks and benefits of student interaction. A further four questions addressed reducing the perceived infection risk. Data is summarised using frequencies and percentages, and with Wilcoxon signed-rank and rank-sum tests of association. Results 85.4% (169/198) of participants gave an initial positive response to seeing medical students, and despite a third of participants changing their response 87.9% (174/197) remained willing after the survey resulting in no significant change. Furthermore, 87.2% (41/47) of those who perceived themselves at severe risk of harm from COVID-19 remained happy to see students. Participants reported reassurance knowing students were: fully vaccinated (76.0%); wearing masks (71.5%); lateral flow test negative within the last week (68.0%) and wearing gloves and gown (63.5%). Conclusion This study demonstrated the willingness of patients to engage in medical education despite recognised risks. Patient reflection on the risks and benefits of student interaction did not significantly reduce numbers willing to see students. Even those perceiving a risk of serious harm remained happy to have direct student contact – a demonstration of altruism in medical education. This suggests informed consent should include discussion of infection control measures, risks and benefits to patients and students, and offer alternatives to direct inpatient contact. </jats:sec

Cymantrene–Triazole "Click" Products: Structural Characterization and Electrochemical Properties

We report the first known examples of triazole-derivatized cymantrene complexes (η5-[4-substituted triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I), obtained via a “click” chemical synthesis, bearing a phenyl, 3-aminophenyl, or 4-aminophenyl moiety at the 4-position of the triazole ring. Structural characterization data using multinuclear NMR, UV–vis, ATR-IR, and mass spectrometric methods are provided, as well as crystallographic data for (η5-[4-phenyltriazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I) and (η5-[4-(3-aminophenyl)triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I). Cyclic voltammetric characterization of the redox behavior of each of the three cymantrene–triazole complexes is presented together with digital simulations, in situ infrared spectroelectrochemistry, and DFT calculations to extract the associated kinetic and thermodynamic parameters. The trypanocidal activity of each cymantrene–triazole complex is also examined, and these complexes are found to be more active than cymantrene alone

Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries

Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na–O2 battery performance. Here we show NaO2 as the only discharge product from Na–O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively.Seventh Framework Programme (European Commission) (Marie Curie International Outgoing Fellowship, 2007-2013))National Science Foundation (U.S.) (MRSEC Program, award number DMR-0819762)Robert Bosch GmbH (Bosch Energy Research Network (BERN) Grant)China Clean Energy Research Center-Clean Vehicles Consortium (CERC-CVC) (award number DE-PI0000012)Skolkovo Institute of Science and Technology (Skoltech-MIT Center for Electochemical Energy Storage

Electron donors and cyanoimidazole acceptors: Cyclic voltammetry and molecular orbital study

Voltammetric measurements on a series of cyanoimidazoles and their metal complexes are reported and compared with those for various donors and acceptors measured under the same conditions. LUMO energies from extended Huckel calculations correlate well with reduction potentials of cyanoimidazoles. Extended Huckel calculations also give insights into the interaction of the metal complexes of tetracyanobiimidazole and the nature of molecular stacking.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27187/1/0000190.pd

Tetrabenzoporphyrin and -mono-, - Cis -di- and tetrabenzotriazaporphyrin derivatives: Electrochemical and spectroscopic implications of meso CH Group replacement with nitrogen

Nonperipherally hexyl-substituted metal-free tetrabenzoporphyrin (2H-TBP, 1a) tetrabenzomonoazaporphyrin (2H-TBMAP, 2a), tetrabenzo-cis-diazaporphyrin (2H-TBDAP, 3a), tetrabenzotriazaporphyrin (2H-TBTAP, 4a), and phthalocyanine (2H-Pc, 5a), as well as their copper complexes (1b-5b), were synthesized. As the number of meso nitrogen atoms increases from zero to four, Îmax of the Q-band absorption peak becomes red-shifted by almost 100 nm, and extinction coefficients increased at least threefold. Simultaneously the blue-shifted Soret (UV) band substantially decreased in intensity. These changes were related to the relative electron-density of each macrocycle expressed as the group electronegativity sum of all meso N and CH atom groups, âχR. X-ray photoelectron spectroscopy differentiated between the three different types of macrocyclic nitrogen atoms (the Ninner, (NH)inner, and Nmeso) in the metal-free complexes. Binding energies of the Nmeso and Ninner,Cu atoms in copper chelates could not be resolved. Copper insertion lowered especially the cathodic redox potentials, while all four observed redox processes occurred at larger potentials as the number of meso nitrogens increased. Computational chemical methods using density functional theory confirmed 1b to exhibit a Cu(II) reduction prior to ring-based reductions, while for 2b, Cu(II) reduction is the first reductive step only if the nonperipheral substituents are hydrogen. When they are methyl groups, it is the second reduction process; when they are ethyl, propyl, or hexyl, it becomes the third reductive process. Spectro-electrochemical measurements showed redox processes were associated with a substantial change in intensity of at least two main absorbances (the Q and Soret bands) in the UV spectra of these compounds