Browsing by Author "Luo X"

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    Non-Targeted Metabolomic Profiling Identifies Metabolites with Potential Antimicrobial Activity from an Anaerobic Bacterium Closely Related to Terrisporobacter Species.
    (MDPI (Basel, Switzerland), 2023-02-09) Pahalagedara ASNW; Flint S; Palmer J; Brightwell G; Luo X; Li L; Gupta TB; Eisenreich W
    This work focused on the metabolomic profiling of the conditioned medium (FS03CM) produced by an anaerobic bacterium closely related to Terrisporobacter spp. to identify potential antimicrobial metabolites. The metabolome of the conditioned medium was profiled by two-channel Chemical Isotope Labelling (CIL) LC-MS. The detected metabolites were identified or matched by conducting a library search using different confidence levels. Forty-eight significantly changed metabolites were identified with high confidence after the growth of isolate FS03 in cooked meat glucose starch (CMGS) medium. Some of the secondary metabolites identified with known antimicrobial activities were 4-hydroxyphenyllactate, 3-hydroxyphenylacetic acid, acetic acid, isobutyric acid, valeric acid, and tryptamine. Our findings revealed the presence of different secondary metabolites with previously reported antimicrobial activities and suggested the capability of producing antimicrobial metabolites by the anaerobic bacterium FS03.
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    Sub-micron moulding topological mass transport regimes in angled vortex fluidic flow
    (The Royal Society of Chemistry, 2021-06-07) Alharbi TMD; Jellicoe M; Luo X; Vimalanathan K; Alsulami IK; Al Harbi BS; Igder A; Alrashaidi FAJ; Chen X; Stubbs KA; Chalker JM; Zhang W; Boulos RA; Jones DB; Quinton JS; Raston CL
    Shear stress in dynamic thin films, as in vortex fluidics, can be harnessed for generating non-equilibrium conditions, but the nature of the fluid flow is not understood. A rapidly rotating inclined tube in the vortex fluidic device (VFD) imparts shear stress (mechanical energy) into a thin film of liquid, depending on the physical characteristics of the liquid and rotational speed, ω, tilt angle, θ, and diameter of the tube. Through understanding that the fluid exhibits resonance behaviours from the confining boundaries of the glass surface and the meniscus that determines the liquid film thickness, we have established specific topological mass transport regimes. These topologies have been established through materials processing, as spinning top flow normal to the surface of the tube, double-helical flow across the thin film, and spicular flow, a transitional region where both effects contribute. The manifestation of mass transport patterns within the film have been observed by monitoring the mixing time, temperature profile, and film thickness against increasing rotational speed, ω. In addition, these flow patterns have unique signatures that enable the morphology of nanomaterials processed in the VFD to be predicted, for example in reversible scrolling and crumbling graphene oxide sheets. Shear-stress induced recrystallisation, crystallisation and polymerisation, at different rotational speeds, provide moulds of high-shear topologies, as 'positive' and 'negative' spicular flow behaviour. 'Molecular drilling' of holes in a thin film of polysulfone demonstrate spatial arrangement of double-helices. The grand sum of the different behavioural regimes is a general fluid flow model that accounts for all processing in the VFD at an optimal tilt angle of 45°, and provides a new concept in the fabrication of novel nanomaterials and controlling the organisation of matter.
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    Vortex fluidic induced mass transfer across immiscible phases
    (The Royal Society of Chemistry, 2022-03-28) Jellicoe M; Igder A; Chuah C; Jones DB; Luo X; Stubbs KA; Crawley EM; Pye SJ; Joseph N; Vimalananthan K; Gardner Z; Harvey DP; Chen X; Salvemini F; He S; Zhang W; Chalker JM; Quinton JS; Tang Y; Raston CL
    Mixing immiscible liquids typically requires the use of auxiliary substances including phase transfer catalysts, microgels, surfactants, complex polymers and nano-particles and/or micromixers. Centrifugally separated immiscible liquids of different densities in a 45° tilted rotating tube offer scope for avoiding their use. Micron to submicron size topological flow regimes in the thin films induce high inter-phase mass transfer depending on the nature of the two liquids. A hemispherical base tube creates a Coriolis force as a ‘spinning top’ (ST) topological fluid flow in the less dense liquid which penetrates the denser layer of liquid, delivering liquid from the upper layer through the lower layer to the surface of the tube with the thickness of the layers determined using neutron imaging. Similarly, double helical (DH) topological flow in the less dense liquid, arising from Faraday wave eddy currents twisted by Coriolis forces, impact through the less dense liquid onto the surface of the tube. The lateral dimensions of these topological flows have been determined using ‘molecular drilling’ impacting on a thin layer of polysulfone on the surface of the tube and self-assembly of nanoparticles at the interface of the two liquids. At high rotation speeds, DH flow also occurs in the denser layer, with a critical rotational speed reached resulting in rapid phase demixing of preformed emulsions of two immiscible liquids. ST flow is perturbed relative to double helical flow by changing the shape of the base of the tube while maintaining high mass transfer between phases as demonstrated by circumventing the need for phase transfer catalysts. The findings presented here have implications for overcoming mass transfer limitations at interfaces of liquids, and provide new methods for extractions and separation science, and avoiding the formation of emulsions.