The gas phase of hydrogen fluoride has been investigated by neutron diffraction experiments at three different particle densities. All investigated states are within the liquid-gas coexistence region of hydrogen fluoride. From the obtained diffraction data we deduced information about the local structure of the gas phase, which consists of small agglomerates. This has been expected as liquid hydrogen fluoride forms the strongest hydrogen bonds known. Molecular dynamics simulations with a modified potential have been carried out for all experimentally investigated states. The results confirmed that the size of the formed agglomerates in the gas phase is growing with increasing density of the gas phase.
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http://dx.doi.org/10.1063/1.1877232 | DOI Listing |
Inorg Chem
December 2024
Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States.
The nonheme iron(II) complexes containing a fluoride anion, Fe(BNPAO)(F) () and [Fe(BNPAOH)(F)(THF)](BF) (), were synthesized and structurally characterized. Addition of dioxygen to either or led to the formation of a fluoride-bridged, dinuclear iron(III) complex [Fe(BNPAO)(F)(μ-F)] (), which was characterized by single-crystal X-ray diffraction, H NMR, and elemental analysis. An iron(II)(iodide) complex, Fe(BNPAO)(I) (), was prepared and reacted with O to give the mononuclear complex -Fe(BNPAO)(OH)(I) ().
View Article and Find Full Text PDFMembranes (Basel)
December 2024
PSI Center for Energy and Environmental Sciences, 5232 Villigen PSI, Switzerland.
The impeding ban on per- and polyfluoroalkyl substances (PFAS) prompted researchers to focus on hydrocarbon-based materials as constituents of next-generation proton exchange membranes (PEMs) for polymer electrolyte fuel cells (PEFCs). Here, we report on the fuel cell performance and durability of fluorine-lean PEMs prepared by the post-sulfonation of co-grafted α-methylstyrene (AMS) and 2-methylene glutaronitrile (MGN) monomers into preirradiated 12 µm polyvinylidene fluoride (PVDF) base film. The membranes were subjected to two distinctly different accelerated stress test (AST) protocols performed at open-circuit voltage (OCV): the US Department of Energy-similar chemical AST (90 °C, 30% relative humidity (RH), H/air, 1 bar), developed originally for perfluoroalkylsulfonic acid (PFSA) membranes, and the high relative humidity AST (80 °C, 100% RH, H/O, 2.
View Article and Find Full Text PDFJ Funct Biomater
December 2024
Department of Maxillofacial Orthopaedics and Orthodontics, Pomeranian Medical University in Szczecin, Al. Powst. Wlkp. 72, 70111 Szczecin, Poland.
Bacterial infections are a common cause of clinical complications associated with the use of orthodontic microimplants. Biofilm formation on their surfaces and subsequent infection of peri-implant tissues can result in either exfoliation or surgical removal of these medical devices. In order to improve the properties of microimplants, hybrid coatings enriched with silver nanoparticles, calcium, and phosphorus were investigated.
View Article and Find Full Text PDFClin Oral Investig
December 2024
Department of Pedodontics, Faculty of Dentistry, Izmir Katip Celebi University, Izmir, Turkey.
Objectives: This study aims to comparatively assess the preventive and protective effects of the self-assembling peptide P-4 on enamel erosion and evaluate the potential for enamel surface recovery when professional products are combined with home-use dental-care products during the erosive process.
Materials And Methods: Ninety-nine bovine incisors were divided into nine groups: a control group, four groups with the application of professional-products [P-4 peptide (Curodont-Repair), stannous/Sn containing solution (8% Sn), casein-phosphopeptide-amorphous-calcium-phosphate fluoride/CPP-ACPF (MI Varnish), sodium fluoride/NaF (Profluorid)] and four groups with the combination of professional products and home-use daily dental care products [P-4 peptide (Curodont Repair + Curodont Protect), stannous ions containing agents (8% Sn+Emofluor Gel Intensive-Care), CPP-ACPF (MI Varnish + MI Paste Plus), NaF (Profluorid + ReminPro)]. Professional products were applied once before a five-day erosive cycle, involving six 2-minute citric-acid exposures per day.
Clin Oral Investig
December 2024
Oral Health Research Institute, Indiana University School of Dentistry, 415 Lansing Street, Indianapolis, IN, 46202-2876, USA.
Objectives: Daily-use fluoride products are first-line protection against enamel wear from dietary-acid exposure (DAE). This study aimed to understand effects of fluoride concentration, fluoride salt, product form and ingredients in daily-use products on remineralisation and demineralisation, via network meta-analysis (NMA) of 14 studies using one well-established in-situ model. Remineralisation (surface-microhardness recovery, SHMR) after treatment, and protection against subsequent demineralisation (acid-resistance ratio, ARR) were measured.
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