Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

Acetylene and Ethylene Adsorption on a β‑Mo₂C(100) Surface: A Periodic DFT Study on the Role of C- and Mo-Terminations for Bonding and Hydrogenation Reactions

Mo₂C catalysts are widely used in hydrogenation reactions; however, the role of the C and Mo terminations in these catalysts is not clear. Understanding the binding of adsorbates is key for explaining the activity of Mo₂C. The adsorption of acetylene and ethylene, probe molecules representing alkynes and olefins, respectively, was studied on a β-Mo₂C­(100) surface with C and Mo terminations using calculations based on periodic density functional theory. Moreover, the role of the C/Mo molar ratio was investigated to compare the catalytic potential of cubic (δ-MoC) and orthorhombic (β-Mo₂C) surfaces. The geometry and electronic properties of the clean δ-MoC(001) and β-Mo₂C­(100) surfaces have a strong influence on the binding of unsaturated hydrocarbons. The adsorption of ethylene is weaker than that of acetylene on the surfaces of the cubic and orthorhombic systems; adsorption of the hydrocarbons was stronger on β-Mo₂C­(100) than on δ-MoC(001). The C termination in β-Mo₂C­(100) actively participates in both acetylene and ethylene adsorption and is not merely a spectator. The results of this work suggest that the β-Mo₂C­(100)-C surface could be the one responsible for the catalytic activity during the hydrogenation of unsaturated CC and CC bonds, while the Mo-terminated surface could be poisoned or transformed by the strong adsorption of C and CH_<i>x</i> fragments

Systematic Theoretical Study of Ethylene Adsorption on δ‑MoC(001), TiC(001), and ZrC(001) Surfaces

A systematic study of ethylene adsorption over δ-MoC(001), TiC(001), and ZrC(001) surfaces was conducted by means of calculations based on periodic density functional theory. The structure and electronic properties of each carbide pristine surface had a strong influence in the bonding of ethylene. It was found that the metal and carbon sites of the carbide could participate in the adsorption process. As a consequence of this, very different bonding mechanisms were seen on δ-MoC(001) and TiC(001). The bonding of the molecule on the TMC­(001) systems showed only minor similarities to the type of bonding found on a typical metal like Pt(111). In general, the ethylene binding energy follow the trend in stability: ZrC(001) < TiC(001) < δ-MoC(001) < Pt(111). The van der Waals correction to the energy produces large binding energy values, modifies the stability orders and drives the ethylene closer to the surface but the adsorbate geometry parameters remain unchanged. Ethylene was activated on clearly defined binding geometries, changing its hybridization from sp² to sp³ with an elongation (0.16–0.31 Å) of the CC bond. On the basis of this theoretical study, δ-MoC(001) is proposed as a potential catalyst for the hydrogenation of olefins, whereas TiC(001) could be useful for their hydrogenolysis

Role of the Anchored Groups in the Bonding and Self-Organization of Macrocycles: Carboxylic versus Pyrrole Groups

A combination of variable temperature scanning tunneling microscopy, near edge X-ray adsorption fine structure and density functional theory has been used to investigate the chemisorption and self-assembly of metal-free protoporphyrin IX molecules on Cu(110) surface. The molecules in contact with the substrate suffer irreversible molecular transformations, mainly deprotonation of the carboxylic groups and metalation of the pyrroline subunits. The carboxylate group has been revealed as the anchored group versus the tetrapyrrole ring. We study the role played by the carboxylic acid groups in the surface-molecular bonding and how its presence affects the supramolecular structure

Ring-Opening (ROP) versus Ring-Expansion (REP) Polymerization of ε‑Caprolactone To Give Linear or Cyclic Polycaprolactones

Macromolecular engineering of cyclic polycaprolactones has been carried out by a ring-expansion procedure catalyzed by a series of alkyl-organoaluminum initiators. The single-site nature of the initiators allows a very well-controlled macrolactonization process to give moderate to high molecular weight cyclic polymers with narrow polydispersities. Cyclic architectures are supported by a combination of techniques such as viscosity measurements, NMR, and MALDI-TOF MS analysis

Guanidine Substitutions in Naphthyl Systems to Allow a Controlled Excited-State Intermolecular Proton Transfer: Tuning Photophysical Properties in Aqueous Solution

The excited-state intermolecular proton transfer process (ESPT) in aqueous solution is achieved and controlled by the incorporation of guanidine groups in a fluorescent structure. The bisguanidine under investigation exhibits a dual fluorescence emission with a very high Stokes shifts in water, ≈86 (7890) and 210 (14 500) nm (cm^–1), and an excited-stated deprotonation coupled to an intramolecular charge transfer (ICT) process contributes to this emission. The study demonstrates that the emission properties of the different protonation states are strongly dependent on the solvent environment, which also allows luminescence of the molecule to be tuned. The results of this work show the potential utility of guanidine substitution for the stabilization of ESPT–ICT processes in water and allow the subsequent logical design of new stimulus-responsive fluorophores