In France, the medical community is deeply engaged in a pivotal debate surrounding a draft bill that is set to be presented to the Presidential Cabinet for legalising active assistance in dying.1 The ...heart of this debate centres around the proposed addition within the bill of exceptional euthanasia, where the lethal drug is directly administered by a medical professional, alongside assisted suicide, where the individuals self-administer the lethal medication provided by a health-care professional; this addition is aimed at ensuring equal access to active assistance in dying for individuals with motor disabilities. The existing legal framework (law number 2002–303 as of March 4, 2002, relative to the rights of the sick and the quality of the health ) permits patients with ALS to refuse life-sustaining treatments such as enteral nutrition, artificial hydration, or mechanical ventilation. P-FPe is President of the ethical committee of the Montpellier University Hospital and President of the ethical committee of the French Society of Anesthesiology and Intensive Care.
We provide an overview of the successive steps that made it possible to obtain increasingly accurate excitation energies with computational chemistry tools, eventually leading to chemically accurate ...vertical transition energies for small- and medium-size molecules. First, we describe the evolution of ab initio methods employed to define benchmark values, with the original Roos CASPT2 method, then the CC3 method as in the renowned Thiel set, and more recently the resurgence of selected configuration interaction methods. The latter method has been able to deliver consistently, for both single and double excitations, highly accurate excitation energies for small molecules, as well as medium-size molecules with compact basis sets. Second, we describe how these high-level methods and the creation of representative benchmark sets of excitation energies have allowed the fair and accurate assessment of the performance of computationally lighter methods. We conclude by discussing possible future theoretical and technological developments in the field.
The Bethe–Salpeter equation (BSE) formalism is steadily asserting itself as a new efficient and accurate tool in the ensemble of computational methods available to chemists in order to predict ...optical excitations in molecular systems. In particular, the combination of the so-called GW approximation, giving access to reliable ionization energies and electron affinities, and the BSE formalism, able to model UV/vis spectra, has shown to provide accurate singlet excitation energies with a typical error of 0.1–0.3 eV. With a similar computational cost as time-dependent density-functional theory (TD-DFT), BSE is able to provide an accuracy on par with the most accurate global and range-separated hybrid functionals without the unsettling choice of the exchange–correlation functional, resolving further known issues (e.g., charge-transfer excitations). In this Perspective, we provide a historical overview of BSE, with a particular focus on its condensed-matter roots. We also propose a critical review of its strengths and weaknesses in different chemical situations.
Severe community-acquired pneumonia caused by Streptococcus pneumoniae is associated with high morbidity and mortality rates. CAL02, a novel antitoxin agent with an unprecedented mode of action, ...consists of liposomes that capture bacterial toxins known to dysregulate inflammation, cause organ damage, and impede immune defence. We aimed to assess the safety of CAL02 as an add-on therapy to antibiotics.
This randomised, double-blind, multicentre, placebo-controlled trial was done in ten intensive care units (ICUs) in France and Belgium (but only six units enrolled patients), in patients with severe community-acquired pneumococcal pneumonia who required ICU admission and had been identified as being infected with S pneumoniae. We randomly assigned participants in two stages—the first stage randomly assigned six patients (1:1) to either low-dose CAL02 or placebo, and the second stage randomly assigned 18 patients (14:4) to either high-dose CAL02 or placebo, and stratified in four blocks (4:1, 4:1, 3:1, and 3:1), in addition to standard of care. Block randomisation was done with a computer-generated random number list. Participants, investigators, other site study personnel, the sponsor, and the sponsor's designees involved in study management and monitoring were masked to the randomisation list and treatment assignment. Patients were treated with low-dose (4 mg/kg) or high-dose (16 mg/kg) CAL02 or placebo (saline), in addition to standard antibiotic therapy. Two intravenous doses of study treatment were infused, with a 24 h interval, at a concentration of 10 mg/mL, stepwise, over a maximum of 2 h on days 1 and 2. The primary objective of the study was to assess the safety and tolerability of low-dose and high-dose CAL02 in patients with severe community-acquired pneumonia treated with standard antibiotic therapy, and the primary analysis was done on the safety population (all patients who received at least one dose of the study treatment). Efficacy was a secondary outcome. This trial is registered with ClinicalTrials.gov, number NCT02583373.
Between March 21, 2016, and Jan 13, 2018, we screened 280 patients with community-acquired pneumonia. 19 patients were enrolled and randomly assigned, resulting in 13 patients in the CAL02 groups (three assigned to low-dose CAL02 and ten assigned to high-dose CAL02) and six in the placebo group. One patient randomly assigned to placebo was allocated to the wrong treatment group and received high-dose CAL02 instead of placebo. Thus, 14 patients received CAL02 (three received low-dose CAL02 and 11 received high-dose CAL02) and five patients received placebo, constituting the safety population. At baseline, the mean APACHE II score for the total study population was 21·5 (SD 4·9; 95% CI 19·3–23·7) and 11 (58%) of 19 patients had septic shock. Adverse events occurred in 12 (86%) of 14 patients in the CAL02 treatment groups combined and all five (100%) patients in the placebo group. Serious adverse events occurred in four (29%) of 14 patients in the CAL02 treatment groups combined and two (40%) of five patients in the placebo group. One non-serious adverse event (mild increase in triglycerides) in a patient in the high-dose CAL02 group was reported as related to study drug. However, analysis of the changes in triglyceride levels in the CAL02 groups compared with the placebo group revealed no correlation with administration of CAL02. No adverse events were linked to local tolerability events. All patients, apart from one who died in the low CAL02 group (death not related to the study drug) achieved clinical cure at the test of cure visit between days 15 and 22. The sequential organ failure assessment score decreased by mean 65·0% (95% CI 50·7–79·4) in the combined CAL02 groups compared with 29·2% (12·8–45·5) in the placebo group between baseline and day 8.
The nature of adverse events was consistent with the profile of the study population and CAL02 showed a promising safety profile and tolerability. However, the difference between high-dose and low-dose CAL02 could not be assessed in this study. Efficacy was in line with the expected benefits of neutralising toxins. The results of this study support further clinical development of CAL02 and provide a solid basis for a larger clinical study.
Combioxin.
Striving to define very accurate vertical transition energies, we perform both high-level coupled cluster (CC) calculations (up to CCSDTQP) and selected configuration interaction (sCI) calculations ...(up to several millions of determinants) for 18 small compounds (water, hydrogen sulfide, ammonia, hydrogen chloride, dinitrogen, carbon monoxide, acetylene, ethylene, formaldehyde, methanimine, thioformaldehyde, acetaldehyde, cyclopropene, diazomethane, formamide, ketene, nitrosomethane, and the smallest streptocyanine). By systematically increasing the order of the CC expansion, the number of determinants in the CI expansion as well as the size of the one-electron basis set, we have been able to reach near full CI (FCI) quality transition energies. These calculations are carried out on CC3/aug-cc-pVTZ geometries, using a series of increasingly large atomic basis sets systematically including diffuse functions. In this way, we define a list of 110 transition energies for states of various characters (valence, Rydberg, n → π*, π → π*, singlet, triplet, etc.) to be used as references for further calculations. Benchmark transition energies are provided at the aug-cc-pVTZ level as well as with additional basis set corrections, in order to obtain results close to the complete basis set limit. These reference data are used to benchmark a series of 12 excited-state wave function methods accounting for double and triple contributions, namely ADC(2), ADC(3), CIS(D), CIS(D∞), CC2, STEOM-CCSD, CCSD, CCSDR(3), CCSDT-3, CC3, CCSDT., and CCSDTQ. It turns out that CCSDTQ yields a negligible difference with the extrapolated CI values with a mean absolute error as small as 0.01 eV, whereas the coupled cluster approaches including iterative triples are also very accurate (mean absolute error of 0.03 eV). Consequently, CCSDT-3 and CC3 can be used to define reliable benchmarks. This observation does not hold for ADC(3) that delivers quite large errors for this set of small compounds, with a clear tendency to overcorrect its second-order version, ADC(2). Finally, we discuss the possibility to use basis set extrapolation approaches so as to tackle more easily larger compounds.
Using a set of oscillator strengths and excited-state dipole moments of near full configuration interaction quality determined for small compounds, we benchmark the performances of several ...single-reference wave function methods CC2, CCSD, CC3, CCSDT, ADC(2), and ADC(3/2) and time-dependent density-functional theory (TD-DFT) with various functionals (B3LYP, PBE0, M06-2X, CAM-B3LYP, and ωB97X-D). We consider the impact of various gauges (length, velocity, and mixed) and formalisms: equation of motion versus linear response, relaxed versus unrelaxed orbitals, and so forth. Beyond the expected accuracy improvements and a neat decrease of formalism sensitivity when using higher-order wave function methods, the present contribution shows that, for both ADC(2) and CC2, the choice of gauge impacts more significantly the magnitude of the oscillator strengths than the choice of formalism and that CCSD yields a notable improvement on this transition property as compared to CC2. For the excited-state dipole moments, switching on orbital relaxation appreciably improves the accuracy of both ADC(2) and CC2 but has a rather small effect at the CCSD level. Going from ground to excited states, the typical errors on dipole moments for a given method tend to roughly triple. Interestingly, the ADC(3/2) oscillator strengths and dipoles are significantly more accurate than their ADC(2) counterparts, whereas the two models do deliver rather similar absolute errors for transition energies. Concerning TD-DFT, one finds: (i) a rather negligible impact of the gauge on oscillator strengths for all tested functionals (except for M06-2X); (ii) deviations of ca. 0.10 D on ground-state dipoles for all functionals; (iii) strong differences between excited-state dipoles obtained with, on the one hand, B3LYP and PBE0 and, on the other hand, M06-2X, CAM-B3LYP, and ωB97X-D, the latter group being markedly more accurate with the selected basis set; and (iv) the better overall performance of CAM-B3LYP for the two considered excited-state properties. Finally, for all investigated properties, both the accuracy and consistency obtained with the second-order wave function approaches, ADC(2) and CC2, do not clearly outperform those of TD-DFT, hinting that assessing the accuracy of the latter (or selecting a specific functional) on the basis of the results of the former is not systematically a well-settled strategy.
Following our previous work focusing on compounds containing up to 3 non-hydrogen atoms J. Chem. Theory Comput. 2018, 14, 4360–4379, we present here highly accurate vertical transition energies ...obtained for 27 molecules encompassing 4, 5, and 6 non-hydrogen atoms: acetone, acrolein, benzene, butadiene, cyanoacetylene, cyanoformaldehyde, cyanogen, cyclopentadiene, cyclopropenone, cyclopropenethione, diacetylene, furan, glyoxal, imidazole, isobutene, methylenecyclopropene, propynal, pyrazine, pyridazine, pyridine, pyrimidine, pyrrole, tetrazine, thioacetone, thiophene, thiopropynal, and triazine. To obtain these energies, we use equation-of-motion/linear-response coupled cluster theory up to the highest technically possible excitation order for these systems (CC3, EOM-CCSDT, and EOM-CCSDTQ) and selected configuration interaction (SCI) calculations (with tens of millions of determinants in the reference space), as well as the multiconfigurational n-electron valence state perturbation theory (NEVPT2) method. All these approaches are applied in combination with diffuse-containing atomic basis sets. For all transitions, we report at least CC3/aug-cc-pVQZ vertical excitation energies as well as CC3/aug-cc-pVTZ oscillator strengths for each dipole-allowed transition. We show that CC3 almost systematically delivers transition energies in agreement with higher-level methods with a typical deviation of ±0.04 eV, except for transitions with a dominant double excitation character where the error is much larger. The present contribution gathers a large, diverse, and accurate set of more than 200 highly accurate transition energies for states of various natures (valence, Rydberg, singlet, triplet, n → π*, π → π*, ...). We use this series of theoretical best estimates to benchmark a series of popular methods for excited state calculations: CIS(D), ADC(2), CC2, STEOM-CCSD, EOM-CCSD, CCSDR(3), CCSDT-3, CC3, and NEVPT2. The results of these benchmarks are compared to the available literature data.
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