This paper numerically investigates the effect of mass transfer processes on spherical single bubble dynamics using the Hertz-Langmuir-Knudsen approximation for the mass flux across the interface. Bubble behavior, with and without mass transfer, is studied for different values of pressure wave amplitude and frequency, as well as initial bubble radius. Whereas mass transfer processes do not seem to play a significant role on the bubble response for pressure amplitudes smaller than 0.9 atm, they appear to have an important effect when the amplitude is greater than or equal to 1 atm. For the later case, where the minimum liquid pressure reaches values around its vapor pressure, the importance of mass transfer depends on frequency. For frequencies in the 10(3)-10(5) Hz range and initial bubble radii of the order of tens of microns, bubble implosions with and with no mass transfer are significantly different; smaller radii display a lower sensitivity. In this regime, accurate model predictions must, therefore, carefully select the correct value of the accommodation coefficient. For frequencies greater than 10(5) Hz, as a first approximation mass transfer can be ignored.
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http://dx.doi.org/10.1121/1.3436520 | DOI Listing |
PLoS One
January 2025
Transfers, Interfaces and Processes, Université libre de Bruxelles, Brussels, Belgium.
In this paper, we present a new computational framework for the simulation of airway resistance, the fraction of exhaled nitric oxide, and the diffusion capacity for nitric oxide in healthy and unhealthy lungs. Our approach is firstly based on a realistic representation of the geometry of healthy lungs as a function of body mass, which compares well with data from the literature, particularly in terms of lung volume and alveolar surface area. The original way in which this geometry is created, including an individual definition of the airways in the first seven generations of the lungs, makes it possible to consider the heterogeneous nature of the lungs in terms of perfusion and ventilation.
View Article and Find Full Text PDFBiochemistry
January 2025
School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, United Kingdom.
The enzyme 4-oxo-l-proline reductase (BDH2) has recently been identified in humans. BDH2, previously thought to be a cytosolic ()-3-hydroxybutyrate dehydrogenase, actually catalyzes the NADH-dependent reduction of 4-oxo-l-proline to -4-hydroxy-l-proline, a compound with known anticancer activity. Here we provide an initial mechanistic characterization of the BDH2-catalyzed reaction.
View Article and Find Full Text PDFAdv Biotechnol (Singap)
October 2024
Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources and Environment, Nanchang University, Nanchang, 330031, China.
Microalgae offer a promising alternative for sustainable nutritional supplements and functional food ingredients and hold potential to meet the growing demand for nutritious and eco-friendly food alternatives. With the escalating impacts of global climate change and increasing human activities, microalgal production must be enhanced by reducing freshwater and land use and minimizing carbon emissions. The advent of 3D printing offers novel opportunities for optimizing microalgae production, though it faces challenges such as high production costs and scalability concerns.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong 999077, China.
Sample pretreatment for mass spectrometry (MS)-based metabolomics and lipidomics is normally conducted independently with two sample aliquots and separate matrix cleanup procedures, making the two-step process sample-intensive and time-consuming. Herein, we introduce a high-throughput pretreatment workflow for integrated nontargeted metabolomics and lipidomics leveraging the enhanced matrix removal (EMR)-lipid microelution 96-well plates. The EMR-lipid technique was innovatively employed to effectively separate and isolate non-lipid small metabolites and lipids in sequence using significantly reduced sample amounts and organic solvents.
View Article and Find Full Text PDFChem Sci
January 2025
Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir Prelog Weg 5 8093 Zurich Switzerland
The labile end-groups inherent to many controlled radical polymerization methodologies, including atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization, can trigger the efficient chemical recycling of polymethacrylates yielding high percentages of pristine monomer. Yet, current thermal solution ATRP and RAFT depolymerization strategies require relatively high temperatures ( 120-170 °C) to proceed, with slower depolymerization rates, and moderate yields often reported under milder reaction conditions ( lower temperatures). In this work, we seek to promote the low temperature RAFT depolymerization of polymethacrylates regulating the Z-group substitution of dithiobenzoate.
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