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JACS Au Feb 2024[This retracts the article DOI: 10.1021/jacsau.2c00402.].
[This retracts the article DOI: 10.1021/jacsau.2c00402.].
PubMed: 38425905
DOI: 10.1021/jacsau.4c00090 -
The Journal of Physical Chemistry. C,... Feb 2024Propane dehydrogenation (PDH) is an on-purpose catalytic technology to produce propylene from propane that operates at high temperatures, 773-973 K. Several key industry...
Propane dehydrogenation (PDH) is an on-purpose catalytic technology to produce propylene from propane that operates at high temperatures, 773-973 K. Several key industry players have been active in developing new catalysts and processes with improved carbon footprint and economics, where Pt-based catalysts have played a central role. The optimization of these catalytic systems through computational and atomistic simulations requires large-scale models that account for their reactivity and dynamic properties. To address this challenge, we developed a new reactive ReaxFF force field () that enables large-scale simulations of PDH reactions catalyzed on Pt surfaces. The optimization of force-field parameters relies on a large training set of density functional theory (DFT) calculations of Pt-catalyzed PDH mechanism, including geometries, adsorption and relative energies of reaction intermediates, and key C-H and C-C bond-breaking/forming reaction steps on the Pt(111) surface. The internal validation supports the accuracy of the developed force-field parameters, resulting in mean absolute errors (MAE) against DFT data of 14 and 12 kJ mol for relative energies of intermediates and energy barriers, respectively. We demonstrated the applicability of the force field with reactive molecular dynamics simulations of propane on different Pt surface topologies and temperatures. The simulations successfully model the formation of propene in the gas phase as well as competitive, unproductive reactions such as deep dehydrogenation and C-C bond cleavage that produce H, C and C adsorbed species responsible of catalytic deactivation of Pt surface. Results show the following reactivity order: Pt(111) < Pt(100) < Pt(211), and that for the stepped Pt(211) surface, propane activation occurs on low-coordinated Pt atoms at the steps. The measured selectivity as a function of surface topology follows the same trend as activity, the Pt(211) facet being the most selective. The reactive force field can also describe the increase of reactivity with the temperature. From these simulations, we were able to estimate the Arrhenius activation energy, 73 kJ mol, whose value is close to those reported experimentally for PDH catalyzed by large, supported Pt nanoparticles . The newly developed reactive force field can be used in subsequent investigations of different Pt topologies and of collective effects such as temperature, propane pressure, or H surface coverage.
PubMed: 38414834
DOI: 10.1021/acs.jpcc.3c07126 -
Journal of Ayub Medical College,... 2023To study the efficacy of a single 0.3ml of C3F8 injection for the treatment of symptomatic VMT.
BACKGROUND
To study the efficacy of a single 0.3ml of C3F8 injection for the treatment of symptomatic VMT.
METHODS
In this retrospective interventional study a total of nine patients were recruited. The mean age was 67 years. Patients had a follow-up at one week and four weeks post injections. VMT status was confirmed on repeat Oct scan.
RESULTS
There was a complete release of VMT In 4 patients after one week and further release of VMT was observed in two more patients after four weeks. Hence six out of nine patients had complete resolution of pathology following C3F8 injection.
CONCLUSIONS
Intravitreal C3F8 is a cheaper and safer option for the treatment of vitreomacular traction as compared to pars plana vitrectomy or Ocriplasmin.
Topics: Humans; Aged; Propane; Retinal Perforations; Retrospective Studies; Traction; Intravitreal Injections; Vision Disorders; Tomography, Optical Coherence
PubMed: 38404073
DOI: 10.55519/JAMC-03-11555 -
Molecules (Basel, Switzerland) Feb 2024Roscoe (ginger) is a plant from the family, and its extracts have been found to contain several compounds with beneficial bioactivities. Nowadays, the use of...
Roscoe (ginger) is a plant from the family, and its extracts have been found to contain several compounds with beneficial bioactivities. Nowadays, the use of environmentally friendly and sustainable extraction methods has attracted considerable interest. The main objective of this study was to evaluate subcritical propane (scPropane), supercritical CO (scCO), and supercritical CO with ethanol (scCO + EtOH) as co-solvent methods for the extraction of high value products from ginger. In addition, the reuse/recycling of the secondary biomass in a second extraction as a part of the circular economy was evaluated. Both the primary and the secondary biomass led to high yield percentages, ranging from 1.23% to 6.42%. The highest yield was observed in the scCO + EtOH, with biomass prior used to scCO extraction. All extracts presented with high similarities as far as their total phenolic contents, antioxidant capacity, and chemical composition. The most abundant compounds, identified by the two different gas chromatography-mass spectrometry (GC-MS) systems present, were a-zingiberene, β- sesquiphellandrene, a-farnesene, β-bisabolene, zingerone, gingerol, a-curcumene, and γ-muurolene. Interestingly, the reuse/recycling of the secondary biomass was found to be promising, as the extracts showed high antioxidant capacity and consisted of significant amounts of compounds with beneficial properties.
Topics: Zingiber officinale; Antioxidants; Biomass; Carbon Dioxide; Sesquiterpenes; Plant Extracts
PubMed: 38398623
DOI: 10.3390/molecules29040871 -
International Journal of Molecular... Feb 2024A novel and cost-effective heterogeneous catalyst for glycerol carbonate production through transesterification was developed by impregnating smectite clay with KCO....
A novel and cost-effective heterogeneous catalyst for glycerol carbonate production through transesterification was developed by impregnating smectite clay with KCO. Comprehensive structural and chemical analyses, including X-ray diffraction Analysis (XRD), Scanning Electron Microscopy (SEM)-Electron Dispersion Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis measurements, were employed to characterize the catalysts. Among the various catalysts prepared, the one impregnated with 40 wt% KCO on smectite and calcined at 550 °C exhibited the highest catalytic activity, primarily due to its superior basicity. To enhance the efficiency of the transesterification process, several reaction parameters were optimized, including the molar ratio between propylene carbonate and glycerol reactor loading of the catalyst and reaction temperature. The highest glycerol carbonate conversion rate, approximately 77.13% ± 1.2%, was achieved using the best catalyst under the following optimal conditions: 2 wt% reactor loading, 110 °C reaction temperature, 2:1 propylene carbonate to glycerol molar ratio, and 6h reaction duration. Furthermore, both the raw clay and the best calcined KCO-impregnated catalysts demonstrated remarkable stability, maintaining their high activity for up to four consecutive reaction cycles. Finally, a kinetic analysis was performed using kinetic data from several runs employing raw clay and the most active KCO-modified clay at different temperatures, observing that a simple reversible second-order potential kinetic model of the quasi-homogeneous type fits perfectly to such data in diverse temperature ranges.
Topics: Clay; Glycerol; Kinetics; Carbonates; Propane; Silicates
PubMed: 38397119
DOI: 10.3390/ijms25042442 -
Microbial Biotechnology Feb 2024Biopreservation refers to the use of natural or controlled microbial single strains or consortia, and/or their metabolites such as short-chain carboxylic acids (SCCA),...
Biopreservation refers to the use of natural or controlled microbial single strains or consortia, and/or their metabolites such as short-chain carboxylic acids (SCCA), to improve the shelf-life of foods. This study aimed at establishing a novel Lactobacillaceae-driven bioprocess that led to the production of the SCCA propionate through the cross-feeding on 1,2-propanediol (1,2-PD) derived from the deoxyhexoses rhamnose or fucose. When grown as single cultures in Hungate tubes, strains of Lacticaseibacillus rhamnosus preferred fucose over rhamnose and produced 1,2-PD in addition to lactate, acetate, and formate, while Limosilactobacillus reuteri metabolized 1,2-PD into propionate, propanol and propanal. Loigolactobacillus coryniformis used fucose to produce 1,2-PD and only formed propionate when supplied with 1,2-PD. Fermentates collected from batch fermentations in bioreactor using two-strain consortia (L. rhamnosus and L. reuteri) or fed-batch fermentations of single strain cultures of L. coryniformis with rhamnose contained mixtures of SCCA consisting of mainly lactate and acetate and also propionate. Synthetic mixtures that contained SCCA at concentrations present in the fermentates were more antimicrobial against Salmonella enterica if propionate was present. Together, this study (i) demonstrates the potential of single strains and two-strain consortia to produce propionate in the presence of deoxyhexoses extending the fermentation metabolite profile of Lactobacillaceae, and (ii) emphasizes the potential of applying propionate-containing fermentates as biopreservatives.
Topics: Propionates; Lactobacillaceae; Rhamnose; Fucose; Fermentation; Acetates; Lactates
PubMed: 38380951
DOI: 10.1111/1751-7915.14392 -
2'-Fucosyllactose helps butyrate producers outgrow competitors in infant gut microbiota simulations.IScience Mar 2024A reduced capacity for butyrate production by the early infant gut microbiota is associated with negative health effects, such as inflammation and the development of...
A reduced capacity for butyrate production by the early infant gut microbiota is associated with negative health effects, such as inflammation and the development of allergies. Here, we develop new hypotheses on the effect of the prebiotic galacto-oligosaccharides (GOS) or 2'-fucosyllactose (2'-FL) on butyrate production by the infant gut microbiota using a multiscale, spatiotemporal mathematical model of the infant gut. The model simulates a community of cross-feeding gut bacteria in metabolic detail. It represents the community as a grid of bacterial populations that exchange metabolites, using 20 different subspecies-specific metabolic networks taken from the AGORA database. The simulations predict that both GOS and 2'-FL promote the growth of , whereas butyrate producing bacteria are only consistently abundant in the presence of propane-1,2-diol, a product of 2'-FL metabolism. In absence of prebiotics or in presence of only GOS, however, and outcompete butyrate producers by consuming intermediate metabolites.
PubMed: 38380251
DOI: 10.1016/j.isci.2024.109085 -
Langmuir monolayer studies of non-ionic surfactants and DOTMA for the design of ophthalmic niosomes.Heliyon Feb 2024The worldwide increase in diabetes entails a rise in associated diseases, with diabetic retinopathy on the forefront of the ocular complications. To overcome the...
The worldwide increase in diabetes entails a rise in associated diseases, with diabetic retinopathy on the forefront of the ocular complications. To overcome the challenges posed by ocular barriers, self-assembled nanocarriers have gathered increasing attention in recent years, with niosomes revealing themselves to be suitable for the delivery of a variety of drugs. This study investigated the mechanical properties of Langmuir monolayers comprising cholesterol, Tween 60, and 1,2-di--octadecenyl-3-trimethylammonium propane (DOTMA), both individually and in binary and ternary systems. The cholesterol monolayer was characterized by an L-shaped isotherm, reflecting two surface aggregation states. Tween 60 exhibited expanded conformation and progressive aggregation, transitioning through a phase change. The addition of cholesterol to Tween 60 resulted in a subtle reduction in surface compressional modulus. The compression isotherms highlighted the stabilizing effect of cholesterol on the monolayer, affecting the film's resistance to compression. The introduction of DOTMA in Tween 60 monolayers revealed concentration-dependent effects, where the compression resistance of the film was proportional to DOTMA concentration. Ternary systems of cholesterol, DOTMA and Tween 60 exhibited unique behavior, with DOTMA enhancing film stability and cholesterol modulating this effect. Temperature and subphase ionic strength variations further exacerbated the effects of DOTMA concentration. Brewster Angle Microscopy confirmed the absence of microdomains in the compressed monolayer, supporting the hypothesis of a monolayer collapse. Overall, the research provided valuable insights into the intricate interactions and mechanical behavior of these surfactant systems and the feasibility of obtaining cationic niosome-based drug delivery.
PubMed: 38380035
DOI: 10.1016/j.heliyon.2024.e25887 -
RSC Advances Feb 2024Fluorinated and formaldehyde-based compounds impart excellent hydrophobicity and flame-retardant properties to cotton fabrics. However, they come with various health and...
Fluorinated and formaldehyde-based compounds impart excellent hydrophobicity and flame-retardant properties to cotton fabrics. However, they come with various health and environmental risks. A novel hydrophobic, flame retardant, and antimicrobial finishing agent free from fluorine and formaldehyde was synthesized. The diammonium phosphate octadecyl citrate (DAPOC) was synthesized by using stearic acid (octadecanoic acid), citric acid (propane-1,2,3-tricarboxylic acid), and diammonium hydrogen phosphate. It was grafted onto the cotton fabrics by employing the conventional pad-dry-cure method. The results indicated that this newly developed finish could be chemically bonded to cotton fabrics through C-O-C covalent bonds. The contact angle of the cotton fabric finished with a 12% concentration of the finishing agent reached 151.9°. Additionally, the finished cotton fabrics displayed evident flame-retardant properties. After undergoing 20 laundering cycles, DAPOC maintained strong hydrophobic and flame-retardant characteristics, demonstrating its durability. The chemical structure of DAPOC was verified by nuclear magnetic resonance spectroscopy (H-NMR). The thermogravimetric analysis confirmed the flame-retardant nature of the treated cotton fabric samples. Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), and Fourier-transform infrared spectroscopy (FTIR) results demonstrated the successful grafting of the newly created finish onto the cotton fiber. X-ray diffraction (XRD) spectra depicted that the crystalline structure of finished cotton fabric remained mostly unaltered. Furthermore, the finished cotton fabric exhibited commendable antimicrobial properties due to the inclusion of citric acid.
PubMed: 38375009
DOI: 10.1039/d3ra07931g -
Scientific Reports Feb 2024Psychedelic substances induce profound alterations in consciousness. Careful preparation is therefore essential to limit adverse reactions, enhance therapeutic benefits,...
Psychedelic substances induce profound alterations in consciousness. Careful preparation is therefore essential to limit adverse reactions, enhance therapeutic benefits, and maintain user safety. This paper describes the development of a self-directed, digital intervention for psychedelic preparation. Drawing on elements from the UK Medical Research Council (MRC) framework for developing complex interventions, the design was informed by a four-factor model of psychedelic preparedness, using a person-centred approach. Our mixed-methods investigation consisted of two studies. The first involved interviews with 19 participants who had previously attended a 'high-dose' psilocybin retreat, systematically exploring their preparation behaviours and perspectives on the proposed intervention. The second study engaged 28 attendees of an ongoing psilocybin retreat in co-design workshops, refining the intervention protocol using insights from the initial interviews. The outcome is a co-produced 21-day digital course (Digital Intervention for Psychedelic Preparation (DIPP)), that is organised into four modules: Knowledge-Expectation, Psychophysical-Readiness, Safety-Planning, and Intention-Preparation. Fundamental components of the course include daily meditation practice, supplementary exercises tied to the weekly modules, and mood tracking. DIPP provides a comprehensive and scalable solution to enhance psychedelic preparedness, aligning with the broader shift towards digital mental health interventions.
Topics: Humans; Hallucinogens; Psilocybin; Mental Health; Consciousness; Pentamidine
PubMed: 38374177
DOI: 10.1038/s41598-024-54642-4