This paper presents a review of the current knowledge on the doubly-charged atomic and molecular positive ions in the planetary atmospheres of the Solar System. It is focused on the terrestrial planets which have a dense atmosphere of N2 or CO2, i.e. Venus, the Earth and Mars, but also includes Titan, the largest satellite of Saturn, which has a dense atmosphere composed mainly of N2 and a few percent of methane. Given the composition of these neutral atmospheres, the following species are considered: C++, N++, O++, CH4++, CO++, N2++, NO++, O2++, Ar++ and CO2++. We first discuss the status of their detection in the atmospheres of planets. Then, we provide a comprehensive review of their complex and original photochemistry, production and loss processes. Synthesis tables are provided for those ions, while a discussion on individual species is also provided. Methods for detecting doubly-charged ions in planetary atmospheres are presented, namely with mass-spectrometry, remote sensing and fine plasma density measurements. A section covers some original applications, like the possible effect of the presence of doubly-charged ions on the escape of an atmosphere, which is a key topic of ongoing planetary exploration, related to the evolution of a planet. The results of models, displayed in a comparative way for Venus, Earth, Mars and Titan, are discussed, as they can predict the presence of doubly-charged ions and will certainly trigger new investigations. Finally we give our view concerning next steps, challenges and needs for future studies, hoping that new scientific results will be achieved in the coming years and feed the necessary interdisciplinary exchanges amongst different scientific communities.

Doubly-charged ions in the planetary ionospheres: a review

Despite their energy-efficient merits as promising light-weight structural materials, magnesium (Mg) based alloys suffer from inadequate corrosion resistance. One primary reason is that the native surface film on Mg formed in air mainly consists of Mg(OH)2 and MgO, which is porous and unprotective, especially in humid environments. Here, we demonstrate an environmentally benign method to grow a protective film on the surface of Mg/Mg alloy samples at room temperature, via a direct reaction of already-existing surface film with excited CO2. Moreover, for samples that have been corroded obviously on surface, the corrosion products can be converted directly to create a new protective surface. Mechanical tests show that compared with untreated samples, the protective layer can elevate the yield stress, suppress plastic instability and prolong compressive strains without peeling off from the metal surface. This environmentally friendly surface treatment method is promising to protect Mg alloys, including those already-corroded on the surface.

Turning a native or corroded Mg alloy surface into an anti-corrosion coating in excited CO2

Mastitis is one of the most economically significant diseases for the dairy industry for backyard farmers in developing countries and high producing herds worldwide. Two of the major factors impeding reduction in the incidence of this disease is [a] the lack of availability of an effective vaccine capable of protecting against multiple etiological agents and [b] propensity of some of the etiological agents to develop persistent antibiotic resistance in biofilms. This is further complicated by the continuing revolving shift in the predominant etiological agents of mastitis, depending upon a multitude of factors such as variability in hygienic practices on farms, easy access leading to overuse of appropriate or inappropriate antibiotics at suboptimal concentrations, particularly in developing countries, and lack of compliance with the recommended treatment schedules. Regardless, Staphylococcus aureus and Streptococcus uberis followed by Escherichia coli, Streptococcus agalactiae has become the predominant etiological agents of bovine mastitis followed Streptococcus agalactiae, Streptococcus dysagalactiae, Klebsiella pneumonia and the newly emerging Mycoplasma bovis. Current approaches being pursued to reduce the negative economic impact of this disease are through early diagnosis of infection, immediate treatment with an antibiotic found to either inhibit or kill the pathogen(s) in vitro using planktonic cultures and the use of the currently marketed vaccines regardless of their demonstrated effectiveness. Given the limitations of breeding programs, including genetic selection to improve resistance against infectious diseases including mastitis, it is imperative to have the availability of an effective broad-spectrum, preferably cross-protective, vaccine capable of protecting against bovine mastitis for reduction in the incidence of bovine mastitis, as well as interrupting the potential cross-species transmission to humans. This overview highlights the major etiological agents, factors affecting susceptibility to mastitis, and the current status of antibiotic-based therapies and prototype vaccine candidates or commercially available vaccines against bovine mastitis as potential preventative strategies. © 2013 Tiwari JG, et al.

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Trends in therapeutic and prevention strategies for management of Bovine Mastitis: An overview

This review comments on the ever expanding range of work using the XRF group of techniques published approximately between April 2012 and March 2013. It presents innovative work as opposed to the wealth of contributions that combine XRF spectrometry in conjunction with other analytical techniques and those descriptions of the valuable routine applications published during the review period. New specialised laboratory instruments, X-ray sources and data processing procedures have been introduced as well as further detector development. Portable and hand-held systems have been increasingly used and the literature represents the widening application of μ-SR techniques for XRF mapping and insights of the sub-cellular metabolisms of animals and plants. Applications using TXRF were published dealing with samples from the pharmaceutical industry, biological tissues, extraterrestrial samples and the analysis of nuclear fuels. Nano-particles feature in many applications and this review is enlivened by reports on more space missions. Climate change, environmental studies and green chemistry feature along with work on archaeological and cultural heritage samples including the authentication of an eighteenth century harpsichord varnish.

2013 Atomic spectrometry update—A review of advances in X-ray fluorescence spectrometry

Global and countrywide prevalence of subclinical and clinical mastitis in dairy cattle and buffaloes by systematic review and meta-analysis.

Dissociation dynamics in chloroform molecule induced by ion impact

https://iopscience.iop.org/article/10.1088/1361-6455/aadc93/pdf

Anisotropy in multiple ionisation of CO by ion collisions at intermediate interaction strengths

https://iopscience.iop.org/article/10.1088/1361-6455/ab17ee/pdf

Orientation dependence of multiple ionisation of a diatomic molecule under proton impact

A combined theoretical and experimental study of the dissociation of the di- and trication of the CH3Cl molecule has been performed. Experimentally, these multi-charged ions were produced after interactions of a CH3Cl effusive jet with a mono-energetic beam of H+ or Ar9+ projectile ions. Theoretically, we mapped the multi-dimensional potential energy surfaces of CH3Cl2+, H2CClH2+ and CH3Cl3+ species in their electronic ground and electronically excited states using post-Hartree-Fock configuration interaction methods. In addition to the obvious bond-breaking ionic fragments (i.e. H+ + CH2Cl+, H+ + CH2Cl2+ and CH3+ + Cl+), the formation of H2+ (+CHCl+ or CHCl2+), H3+ (+CCl+) and HCl+ (+CH2+) was observed upon bond rearrangement after ion impact of CH3Cl. The interaction strength of the incident projectiles is found to affect the relative yields on the observed dissociation channels, however, it has no effect on the kinetic energy releases of the fragmentation pathways. For the observed dissociation channels, plausible formation mechanisms were proposed. These reaction pathways take place on the ground and/or electronic excited potential energy surfaces of the doubly and triply charged CH3Cl ions, where spin-orbit and vibronic couplings are in action. Moreover, this work suggests that the mechanisms undertaken may depend on the multiply charged ion preparation by valence or inner-shell single photon photoionization, fast ion beam impact or ultrafast intense laser ionization.

Pragya Bhatt

Papers

Dissociation dynamics in chloroform molecule induced by ion impact

Anisotropy in multiple ionisation of CO by ion collisions at intermediate interaction strengths

Orientation dependence of multiple ionisation of a diatomic molecule under proton impact

Fragmentation dynamics of CH3Clq+ (q = 2,3): theory and experiment.

Statistical process in nitrogen containing naphthalene derivatives in collision with fast electrons and protons