Molecular and Electronic Structure of Self-Assembled Monolayers Containing Ruthenium(II) Complexes on Gold Surfaces

Ru­(II) bipyridyl complexes were covalently bonded to self-assembled monolayers (SAM) on Au surfaces. Their molecular and electronic structure was studied by means of polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), photoelectron spectroscopies, scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. We found that attaching the Ru complex to the SAM does not cause great modifications to its molecular structure, which retains the alkyl chain 30 deg tilted with respect to the surface normal. Furthermore, the Ru center is located 20 Å away from the metal surface, i.e., at a sufficient distance to prevent direct electronic interaction with the substrate. Indeed the electronic structure of the Ru complex is similar to that of the free molecule with a HOMO molecular orbital mainly based on the Ru center located 2.1 eV below the Fermi edge and the LUMO molecular orbital based on the bipyridine groups located 1 eV above the Fermi level

Oxasqualenoids from <i>Laurencia viridis</i>: Combined Spectroscopic–Computational Analysis and Antifouling Potential

The chemical study of the red alga <i>Laurencia viridis</i> has led to the isolation of four new polyether triterpenoids: 28-hydroxysaiyacenol B (<b>2</b>), saiyacenol C (<b>3</b>), 15,16-epoxythyrsiferol A (<b>4</b>), and 15,16-epoxythyrsiferol B (<b>5</b>). The structures of <b>2</b> and <b>3</b> were established mainly by NMR data analysis and comparison with the well-known metabolite dehydrothyrsiferol (<b>1</b>). However, due to the existence of a nonprotonated carbon within the epoxide functionality, stereochemical assignments in <b>4</b> and <b>5</b> required an in-depth structural study that included NOESY data, <i>J</i>-based configuration analysis, comparison with synthetic models, and DFT calculations. The biological activities of the new metabolites and other related oxasqualenoids were evaluated for the first time against a panel of relevant biofouling marine organisms, and structure–activity conclusions were obtained

Chrastil-Type Approach for Representation of Glycol Loss in Gaseous System

International audienceGlycols are generally used to adjust the water dew-point in natural gas processes to avoid gas hydrate/ice/condensate formation. Their vaporization loss in gaseous systems may happen regularly in the petroleum industry. Glycols have very low solubility in the gas phase and because of difficulty of the corresponding measurement, few sets of experimental data are available in open literature and may not be fully satisfactory. In a previous work, we performed thermodynamic consistency tests in order to prepare reliable data sets for modeling purposes. Application of four widely used correlations in supercritical fluid industry, including the original Chrastil, Adachi and Lu, del Valle and Aguilera, and Mendez-Santiago and Teja, in which the effects of temperature, density of gas (solvent), and pressures on the solubility of glycol are generally taken into account, are investigated to represent the corresponding solubility of ethylene glycol and triethylene glycol in supercritical methane and carbon dioxide between 298.15 and 333.15 K and between 1.606 and 22.06 MPa. It is found that the absolute average deviations (AAD %) of the evaluated glycols solubility by the aforementioned equations from 57 investigated experimental values are around 27%, 18%, 31%, and 17%, respectively

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.The aim of this study was to inform vaccination prioritization by modelling the impact of vaccination on elective inpatient surgery. The study found that patients aged at least 70 years needing elective surgery should be prioritized alongside other high-risk groups during early vaccination programmes. Once vaccines are rolled out to younger populations, prioritizing surgical patients is advantageous