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The development of high-performance and environmentally-compatible lubricants is crucial for minimizing energy losses in mechanical systems and increasing the lifetime of moving mechanical components, thus preserving our environment. While ionic liquids (ILs) have emerged as promising next-generation materials for lubrication purposes owing to their attractive physico-chemical properties, several challenges currently limit their use in engineering applications, including their high cost and corrosivity. Recently, eco-friendly, protic ILs (PILs) have been synthesized and showed great advantages compared to tradition (aprotic) ILs, such as low cost, ease of preparation, and good lubricating properties. Despite these advancements, remarkably little is known about the interrelationship between PIL molecular structure and lubrication mechanisms. In this work, the physico-chemical and lubricating properties of a family of PILs synthesized by using only renewable, biodegradable, and biocompatible products and constituted by the same choline cation and amino-acid anions with different side chains, were investigated. The molecular structures of the choline amino acid-based ionic liquids (AAILs) were confirmed through magnetic resonance and Fourier transform infrared spectroscopy, while their thermal behavior was evaluated by differential scanning calorimetry and thermogravimetric analysis. The antiwear and friction-reducing performance of the choline AAILs when used as neat lubricants was studied as a function of normal load by reciprocating ball-on-flat tribometry using steel-steel contact. Surface analytical measurements (Raman and XPS) performed on the worn steel surfaces confirmed that the excellent lubricating performance of choline AAILs originates from the formation of oxygen- and carbon-rich tribolayers. The formation of these protective layers are influenced by the applied normal load and the molecular structure of the amino acid. The results of this work open the path for the rational design of environmentally-friendly PILs for tribological applications. 

The C-diazeniumdiolate (N-nitrosohydroxylamine) group in the amino acid graminine (Gra) is a newly discovered Fe(III) ligand in microbial siderophores. Graminine was first identified in the siderophore gramibactin, and since this discovery, other Gra-containing siderophores have been identified, including megapolibactins, plantaribactin, gladiobactin, trinickiabactin (gramibactin B), and tistrellabactins. The C-diazeniumdiolate is photoreactive in UV light which provides a convenient characterization tool for this type of of siderophores. This report details the process of genomics-driven identification of bacteria producing Gra-containing siderophores based on selected biosynthetic enzymes, as well as bacterial culturing, isolation and characterization of the C-diazeniumdiolate siderophores containing Gra. 

The recent prediction that honeycomb lattices of Co2+ (3d7) ions could host dominant Kitaev interactions provides an exciting direction for exploration of new routes to stabilizing Kitaev’s quantum spin liquid in real materials. Na3Co2SbO6 has been singled out as a potential material candidate provided that spin and orbital moments couple into a Jeff = 1/2 ground state, and that the relative strength of trigonal crystal field and spin-orbit coupling acting on Co ions can be tailored. Using x-ray linear dichroism (XLD) and x-ray magnetic circular dichroism (XMCD) experiments, alongside configuration interaction calculations, we confirm the counterintuitive positive sign of the trigonal crystal field acting on Co2+ ions and test the validity of the Jeff = 1/2 description of the electronic ground state. The results lend experimental support to recent theoretical predictions that a compression (elongation) of CoO6 octahedra along (perpendicular to) the trigonal axis would drive this cobaltate toward the Kitaev limit, assuming the Jeff = 1/2 character of the electronic ground state is preserved. 

The current study investigates how and under what conditions family obligation benefits Mexican American adolescents’ adjustment. The study used two waves of data from 604 Mexican American adolescents (54.3% female, Mage.wave1 = 12.41 years, SD = 0.97) and their parents. Structural equation modeling revealed that both adolescents’ and parents’ sense of family obligation related to more supportive parenting (i.e., parental monitoring, warmth, and inductive reasoning), which linked to better adolescent adjustment (i.e., sense of life meaning, resilience, and grades). There were parent gender differences: Adolescents’ family obligation was more strongly related to their reports of maternal (vs. paternal) parenting. The links also varied across informants for parenting: (a) individuals’ sense of family obligation related only to their own perceptions of parenting and (b) there were more evident associations between adolescent-reported (vs. parent-reported) parenting and adolescent outcomes.