Spectrally resolved ultraviolet (UV) absorption cross-sections of gas-phase sodium chloride (NaCl), potassium hydroxide (KOH), and sodium hydroxide (NaOH) were measured, for the first time, in hot flue gases at different temperatures. Homogenous gas-phase NaCl, KCl (potassium chloride), NaOH, and KOH at temperatures 1200 K, 1400 K, 1600 K, and 1850 K were prepared in the post-flame zone of laminar flames by seeding nebulized droplets out of aqueous solution of corresponding alkali species. The amount of droplets seeded into the flame was kept constant, so the relative concentration of different alkali species can be derived. The broadband UV absorption cross-section of KCl vapor reported by Leffler et al. was adopted to derive the absorption cross-section curves of NaCl, NaOH, and KOH with the corresponding measured spectrally resolved absorbance spectra. No significant changes in the spectral structures in the absorption cross-sections were found as the temperature varied between 1200 K and 1850 K, except for NaOH at around 320 nm. The difference between the absorption spectral curves of alkali chlorides and hydroxides is significant at wavelengths above 300 nm, which thus can be used to distinguish and obtain the concentrations of alkali chlorides and hydroxides in the broadband UV absorption measurements.
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Cell Mol Life Sci
December 2024
Université Paris-Saclay, CEA, UMR Stabilité Génétique Cellules Souches Et Radiations, iRCM/IBFJ, Laboratoire Des Cellules Souches Germinales, 92265, Fontenay-Aux-Roses, France.
About one in six couples experience fertility problems, and male infertility accounts for about half of these cases. Spermatogenesis originates from a small pool of spermatogonial stem cells (SSCs), which are of interest for the treatment of infertility but remain poorly characterised in humans. Using multiparametric spectral flow cytometric analysis with a 16-colours (16-C) panel of cell markers, we identify novel markers of SSCs and provide insights into unravelling and resolving the heterogeneity of the human spermatogonial cells.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden.
Vibrational polaritons are formed by strong coupling of molecular vibrations and photon modes in an optical cavity. Experiments have demonstrated that vibrational strong coupling can change molecular properties and even affect chemical reactivity. However, the interactions in a molecular ensemble are complex, and the exact mechanisms that lead to modifications are not fully understood yet.
View Article and Find Full Text PDFSensitive detection of incident acoustic waves over a broad frequency band offers a faithful representation of photoacoustic pressure transients of biological microstructures. Here, we propose a plasmon waveguide resonance sensor for responding to the photoacoustic impulses. By sequentially depositing Au, MgF, and SiO films on a coverslip, a composite waveguide layer produces a tightly confined optical evanescent field at the SiO-water interface with extremely strong electric field intensity, enabling the retrieval of photoacoustic signals with an estimated noise-equivalent-pressure (NEP) sensitivity of ∼92 Pa and a -6-dB bandwidth of ∼208 MHz.
View Article and Find Full Text PDFAnal Chem
December 2024
Joint Mass Spectrometry Centre/Chair of Analytical Chemistry, University of Rostock, 18059 Rostock, Germany.
To our knowledge, this study presents the first implementation of wavelength-resolved resonance-enhanced multiphoton ionization (REMPI) spectroscopy under atmospheric pressure ionization conditions using a high-resolution mass spectrometric system. Atmospheric pressure laser ionization MS spectroscopic measurements were conducted on over 70 different polycyclic aromatic hydrocarbons (PAHs) and hetero-PAHs (N, S, and O) in standard solutions, as well as three complex PAH-containing samples. The results demonstrate the successful transfer of REMPI spectroscopy from vacuum to atmospheric pressure conditions, maintaining spectral integrity without significant band broadening.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
Institute of Earth Surface Dynamics, University of Lausanne, Lausanne 1015 CH, Switzerland.
Interactions among microbes, minerals, and organic matter are key controls on carbon, nutrient, and contaminant dynamics in soils and sediments. However, probing these interactions at relevant scales and through time remains an analytical challenge due to both their complex nature and the need for tools permitting nondestructive and real-time analysis at sufficient spatial resolution. Here, we demonstrate the ability and provide analytical recommendations for the submicron-scale characterization of complex mineral-organic microstructures using optical photothermal infrared (O-PTIR) microscopy.
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