From electronic structure to catalytic activity: A single descriptor for adsorption and reactivity on transition-metal carbides

Adsorption and catalytic properties of the polar (111) surface of transition-metal carbides (TMC's) are investigated by density-functional theory. Atomic and molecular adsorption are rationalized with the concerted-coupling model, in which two types of TMC surface resonances (SR's) play key roles. The transition-metal derived SR is found to be a single measurable descriptor for the adsorption processes, implying that the Br{\o}nsted-Evans-Polanyi relation and scaling relations apply. This gives a picture with implications for ligand and vacancy effects and which has a potential for a broad screening procedure for heterogeneous catalysts.Comment: 5 pages, 3 figure

Diagnostic value of presepsin for bacterial infection in cirrhosis: a pilot study

Introduction: Presepsin (or sCD14) has been identified as a protein whose levels increase specifically in the blood of patients with bacterial infections. In this study, we evaluated the clinical performance of sCD14 and its usefulness in the early diagnosis of bacterial infection in decompensated cirrhotic patients. Materials: Seventy patients were enrolled in this study. The mean age of patients was 49.5 years, and 21 were women and 49 men. The heparinized whole blood for the PATHFAST test was used in the evaluation of bacterial infection (T0). The test was repeated after 48 hours (T1); at 96 hours (T2); at 144 hours (T3); then at 15 days (T4) to monitor the clinical responses to therapeutic interventions. Results: Forty-nine patients tested positive for sCD14. The mean sCD14 level was 1854 ± 1744 pg/mL. Microbiological findings confirmed the presence of bacterial infections within 84 ± 4.8 h from enrollment in all 49 positive patients. Thirty-eight patients were considered responders to empirical antibiotic therapy with a decrease of presepsin at the different time points, while an increased level of sCD14 was highlighted in 11 patients. When the test was performed, 45% of the patients showed no signs or symptoms of bacterial infection. At 30 days of follow-up 43 patients survived, and 6 patients died from septic shock. Conclusions: The PATHFAST test highlighted the presence of infection in a very short time (15 minutes), and the presepsin could be considered an early biomarker in patients with cirrhosis. A greater number of patients are necessary to confirm these data

Superinfections in patients treated with teicoplanin as anti SARSCoV2 AGENT

We read with interest the paper by Giacobbe et al. estimating a cumulative risk of developing at least one bloodstream infection (BSI) episode (largely due to Gram-positive pathogens) of almost 50% after 30 days at risk in (2) Similarly, Somers et al. reported an increased risk to develop bacterial superinfections, principally represented by Staphylococcus aureus ventilatory associated pneumonia (VAP), in critically ill patients infected with SARS-CoV-2 and treated with Tocilizumab. (1) We previously described a cohort of intubated patients affected by severe COVID-19pneumonia treated with the best available therapy (BAT), including Tocilizumab and associated with Teicoplanin. (3) This glycopeptide antibiotic was used with a double purpose: as antiviral agent for COVID-19 and as of possible S.aureus superinfection

Steam reforming on transition-metal carbides from density-functional theory

A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2) on early transition-metal carbides (TMC's) is performed by means of density-functional theory calculations. The set of considered surfaces includes the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC, VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces. It is found that carbides provide a wide spectrum of reactivities towards the steam reforming reaction, from too reactive via suitable to too inert. The reactivity is discussed in terms of the electronic structure of the clean surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated alpha-Mo_2C(100) surfaces, are identified as promising steam reforming catalysts. These findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.Comment: 6 pages, 4 figure

Is teicoplanin a complementary treatment option for COVID-19? The question remains

We read with great interest the editorial by Baron et al. suggesting the potential use of teicoplanin as an alternative drug to treat patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]. Indeed, this glycopeptide antibiotic, commonly used to treat Gram-positive bacterial infections, also showed potential complementary antiviral activity against severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and Ebola virus, as previously highlighted by Zhou et al.; moreover, influenza A and B viruses and feline infectious peritonitis virus (FIPV) were reported as potential targets of teicoplanin and its chemical derivatives [2], [1], [2], [3]. Recently, additional studies have provided evidence that SARS-CoV-2, similarly to SARS-CoV, is a cathepsin L-dependent virus: in fact, these viruses require a multistep infection process including (i) receptor binding, (ii) change in spike (S) glycoprotein conformation, and finally (iii) cathepsin L proteolysis of the S protein, crucial for virus entry. Teicoplanin was found to specifically inhibit the activity of cathepsin L and potentially to play a critical role in blocking cell entry of the virus [2,6,7]