53 research outputs found
Chemo-enzymatic one-pot oxidation of cyclohexane via in-situ H2O2 production over supported AuPdPt catalysts
The introduction of dopant concentrations of Pt into supported AuPd nanoparticles, when used in conjunction with an evolved unspecific peroxygenase (UPO) from Agrocybe aegerita (PaDaâI) is demonstrated to offer high efficacy towards the oneâpot selective oxidation of cyclohexane to KA oil (cyclohexanol and cyclohexanone), via the inâsitu synthesis of H2O2. The optimised AuPdPt/TiO2/PaDaâI system achieves significant improvements over analogous AuPd or Pdâonly formulations or the use of commercially available H2O2, with this attributed to the increased rate of H2O2 production by the chemoâcatalyst, which results from the electronic modification of Pd species via Pt incorporation, upon the formation of trimetallic nanoalloys
The Free Fatty Acid-Binding Pocket is a Conserved Hallmark in Pathogenic ÎČ-Coronavirus Spike Proteins from SARS-CoV to Omicron
As coronavirus disease 2019 (COVID-19) persists, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) emerge, accumulating spike (S) glycoprotein mutations. S receptor binding domain (RBD) comprises a free fatty acid (FFA)âbinding pocket. FFA binding stabilizes a locked S conformation, interfering with virus infectivity. We provide evidence that the pocket is conserved in pathogenic ÎČ-coronaviruses (ÎČ-CoVs) infecting humans. SARS-CoV, MERS-CoV, SARS-CoV-2, and VOCs bind the essential FFA linoleic acid (LA), while binding is abolished by one mutation in common coldâcausing HCoV-HKU1. In the SARS-CoV S structure, LA stabilizes the locked conformation, while the open, infectious conformation is devoid of LA. Electron tomography of SARS-CoV-2âinfected cells reveals that LA treatment inhibits viral replication, resulting in fewer deformed virions. Our results establish FFA binding as a hallmark of pathogenic ÎČ-CoV infection and replication, setting the stage for FFA-based antiviral strategies to overcome COVID-19
Water activity in liquid food systems : A molecular scale interpretation
Water activity has historically been and continues to be recognised as a key concept in the area of food science. Despite its ubiquitous utilisation, it still appears as though there is confusion concerning its molecular basis, even within simple, single component solutions. Here, by close examination of the well-known Norrish equation and subsequent application of a rigorous statistical theory, we are able to shed light on such an origin. Our findings highlight the importance of solute-solute interactions thus questioning traditional, empirically based âfree waterâ and âwater structureâ hypotheses. Conversely, they support the theory of âsolute hydration and clusteringâ which advocates the interplay of solute-solute and solute-water interactions but crucially, they do so in a manner which is free of any estimations and approximations
Selective Ammoximation of Ketones via In Situ H2O2 Synthesis
The ammoximation of ketones to the corresponding oxime via the in situ production of H2O2 offers a viable alternative to the current means of industrial-scale production, in particular for the synthesis of cyclohexanone oxime, a key precursor to Nylon-6. Herein, we demonstrate that using a bifunctional catalyst, consisting of Pd-based bimetallic nanoparticles immobilized onto a TS-1 carrier, it is possible to bridge the considerable condition gap that exists between the two key distinct reaction pathways that constitute an in-situ approach (i.e., the direct synthesis of H2O2 and ketone ammoximation). The formation of PdAu nanoalloys is found to be crucial in achieving high reactivity and in promoting catalytic stability, with the optimal formulation significantly outperforming both alternative Pd-based materials and the monometallic Pd analogue
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