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Ascorbic acid mediated hydrolysis of galactomannans
Get PDFAscorbic acid (AA) is an antioxidant widely used in the food industry to prevent colour fade and spoilage. This study assesses the effect of 0.02 wt% AA on the rheology of common food thickeners – galactomannans (GM). GMs immediately exhibit a significant reduction in solution viscosity upon AA addition: guar gum (−67 % ± 7 %), locust bean gum (−47 % ± 5 %), and cassia gum (−58 % ± 4 %). Other food acids at 0.02 wt% showed no decline in viscosity, nor did another reducing agent, potassium iodide. GMs were then mixed with xanthan gum (XG) ± low acyl gellan gum (LAG) and AA's impact was assessed using small amplitude oscillatory shear rheology. As the temperature decreased, the storage modulus decreased in the presence of AA compared to without. The molecular weight (MW) of the GMs ± AA, was assessed using size exclusion chromatography – multi angle light scattering. The reduction in MW, was between 6 and 8 times for each GM, and was supported with analytical ultracentrifugation. This established the hydrolytic decomposition of GMs by AA, leading to a decrease in function due to a reduction in MW. This hydrolytic effect was observed regardless of pH, showing that acid hydrolysis isn't the primary mechanism. This study shows, for the first time, that AA causes extensive degradation of galactomannans, affecting their viscoelastic characteristics. These findings could affect many products; informing decisions on their quality and shelf life, as well as their cost-effectiveness and environmental life cycle
Assessing the Impact of Imaging Parameters on MRI Measurement of Kidney T2
No full textBackgroundT2-mapping has promise to evaluate kidney pathophysiology. Prior studies show a large variance in kidney T2, likely due to the differing acquisition sequences.PurposeTo compare four T2-mapping sequences to investigate kidney T2.Study TypePhantom and prospective in vivo assessments.ParticipantsISMRM/NIST and QASPER phantoms; 8 healthy volunteers (4 female, 30 ± 8 years).Field Strength/Sequence3 T, spin echo-echo planar imaging (SE-EPI), multi-echo-spin echo (ME-SE), Gradient and Spin Echo (GraSE) vendor-provided sequences, and custom T2-prepared EPI, Dual-echo B0-mapping and DREAM B1-mapping.AssessmentT2-mapping accuracy in the ISMRM/NIST phantom in the presence of B0 frequency offset and B1+ by scaling of flip angles, and in the QASPER phantom in the presence of diffusion by altering pump rate compared to being turned off. Participants underwent a single 45-min exam to collect four T2-mapping sequences, B0 and B1 maps. In vivo T2 values compared across sequences and the influence of B0 and B1+ was evaluated.Statistical TestsShapiro–Wilk, Wilcoxon signed-rank, Student's t-test, Coefficient of Variation, Pearson's correlation coefficient, linear mixed effect model. p < 0.05 considered statistically significant.ResultsSE-EPI, ME-SE, GraSE, and T2-prepared EPI had a mean absolute scaled error of 0.52, 0.52, 0.36, and 0.27 over the kidney T2 range of the ISMRM/NIST phantom. GraSE was most robust to perturbations in B0/B1+. In the QASPER phantom, SE-EPI was highly sensitive to diffusion leading to T2 shortening (66%), while multi-echo sequences had lower diffusion sensitivity ordered by shortest echo spacing (ME-SE 81%, T2-prepared EPI 90%, GraSE 95% reduction in T2). In vivo, SE-EPI measured T2 was significantly lower than multi-echo sequences, and SE-EPI and T2-preparation had a −0.52 ± 0.08 and −0.57 ± 0.06 ms/% dependence on B1+.Data ConclusionTo reduce B0, B1+, and diffusion sensitivity for kidney T2-mapping, a multi-echo sequence spanning echo times up to the kidney T2 (~140 ms at 3 T) is recommended. Collecting data with different echo spacings can isolate the diffusion-related T2 component
Salazar's Portugal and General Franco's Empire of Hunger: Famine and Fanaticism in Iberia, 1939–1942
Get PDFThis article analyses the Portuguese Estado Novo's knowledge of, and policy towards, the Spanish famine of 1939–1942. While historians have broadly acknowledged that Spain's economic difficulties and Germany's refusal to supply its ally prevented General Franco from joining the Axis, there is a dearth of studies on Portugal's economic strategy towards its larger Iberian neighbour. Based upon dozens of confidential documents, the article presents new information on the state of hunger in Spain. It demonstrates that the Portuguese dictatorship was aware of both its magnitude and its political reverberations. Meanwhile, it contextualizes Portuguese aid to Spain through an exploration of broader social and economic conditions within Portugal. In light of the evidence presented, the article presents a strong critique of the rationale for, and subsequent effects of, the foreign policy of Portugal's dictator, António de Oliveira Salazar, towards Spain
On p-adic L-functions for GL2n in finite slope Shalika families
No full textIn this paper, we propose and explore a new connection in the study of p-adic L-functions and eigenvarieties. We use it to prove results on the geometry of the cuspidal eigenvariety for GL2n over a totally real number field F at classical points admitting Shalika models. We also construct p-adic L-functions over the eigenvariety around these points. Our proofs proceed in the opposite direction to established methods: rather than using the geometry of eigenvarieties to deduce results about p-adic L-functions, we instead show that non-vanishing of a (standard) p-adic L-function implies smoothness of the eigenvariety at such points. Key to our methods are a family of distribution-valued functionals on (parahoric) overconvergent cohomology groups, which we construct via p-adic interpolation of classical representationtheoretic branching laws for GLn × GLn ⊂ GL2n.More precisely, we use our functionals to attach a p-adic Lfunction to a non-critical refinement π˜ of a regular algebraic cuspidal automorphic representation π of GL2n/F which is spherical at p and admits a Shalika model. Our new parahoric distribution coefficients allow us to obtain optimal non-critical slope and growth bounds for this construction. When π has regular weight and the corresponding p-adic Galois representation is irreducible, we exploit non-vanishing of our functionals to show that the parabolic eigenvariety for GL2n/F is étale at π˜ over an ([F : Q] + 1)-dimensional weight space and contains a dense set of classical points admitting Shalika models. Under a hypothesis on the local Shalika models at bad places which is empty for π of level 1, we construct a p-adic L-function for the family
Comparative study of failure characteristics of different types of energy storage batteries after extrusion deformation
Get PDFThe mechanical safety of energy storage batteries is critical for their application in electric vehicles, smart grids, and portable electronics. While previous studies have primarily focused on thermal and electrical abuse, this work provides a systematic investigation into the mechanical failure mechanisms of lithium iron phosphate (LFP), nickel cobalt manganese oxide (NCM), and sodium-ion batteries (SIBs) under extrusion deformation at varying states of charge (SOC). The results reveal distinct differences in stress–strain behavior, open-circuit voltage (OCV), temperature evolution, and electrochemical impedance responses among battery types and SOC levels. Notably, LFP and NCM batteries exhibit increased yield stress at higher SOCs, whereas SIBs show greater voltage instability and a higher risk of thermal runaway. Electrochemical impedance spectroscopy (EIS) indicates that extrusion increases ohmic and diffusion resistance, while interfacial impedance decreases due to electrode densification. Scanning electron microscopy (SEM) shows that mechanical deformation induces interlayer detachment, cracking, and separator melting in LFP and NCM batteries, with severity increasing at higher SOCs. SIBs display microcrack expansion, particle fragmentation, and inter-particle delamination under similar conditions. This study offers new insights into SOC-dependent failure behaviors under mechanical abuse, contributing to safer battery design and performance optimization in real-world impact scenarios
Impact of reduced pancreatin and bile on Fe and Zn bioaccessibility assessment using the INFOGEST in vitro digestion method with stable isotopic labelling
Get PDFIn a previously proposed stable isotope approach based on the INFOGEST protocol, pancreatin and bile amounts were reduced due to their high mineral content, which interferes with Fe and Zn measurements. The present study examined the impact of reagent reduction on macronutrient digestibility and, consequently, mineral release in ten food samples. Macronutrient digestibility was higher under INFOGEST conditions. However, Fe and Zn solubility were not consistently modified across matrices, although, a general trend of increased solubility was observed in the standard INFOGEST method. Fe solubility increased by 64–91 % in cereals, beans, and nuts but decreased by 48 % in sweet potato. Similarly, Zn solubility increased by 11–75 % in oats, nuts, and leafy vegetables, while it decreased by 18–64 % in potatoes and beans. Overall, the influence of enzymatic action and background minerals could not be isolated, thus standardisation of the INFOGEST method for mineral bioaccessibility assessment is urgently needed
Identifying subjects at risk of liver cirrhosis via a range of thresholds for common fibrosis markers: a Welsh general population-based cohort study
Get PDFBackground: Liver disease is on the increase worldwide, with cirrhosis and liver cancer accounting for around 3.5% of all deaths. Objectives: Investigate the prognostic utility of three non-invasive liver fibrosis markers in the Welsh primary care population for identification of those at risk of cirrhosis or hepatocellular carcinoma (HCC). Methods: Using the Secure Anonymised Information Linkage (SAIL) Databank at Swansea University (2000–2017), we identified people with liver blood tests allowing calculation of three commonly used liver fibrosis markers: aspartate transaminase to alanine transaminase (AST/ALT) ratio, AST to platelet ratio index (APRI) and fibrosis-4 index (FIB-4). We modelled 10-year risk of cirrhosis/HCC across a range of thresholds using competing risk survival analysis and compared their prognostic value using decision curve analysis (DCA). Results: Blood tests enabling calculation of FIB-4, APRI and AST/ALT were available for 203,005 people. At commonly utilized cut-points to detect advanced fibrosis/cirrhosis of 3.25, 1.5 and 1.0 for FIB-4, APRI and AST/ALT, respectively, the 10-year risks of cirrhosis/HCC were 4.7%, 16% and <1%. DCA demonstrated the APRI has the greatest net benefit for estimating cirrhosis/HCC risk over 10 years, in a general population compared to AST/ALT or FIB-4. In higher risk subgroups, a greater proportion of at-risk patients were captured for fewer referrals. This was also observed in groups with combinations of risk factors. Conclusion: At risk thresholds often used for referral, liver fibrosis markers had prohibitively high false positive rates unless restricted to subgroups at increased risk of developing severe liver disease
The interaction of 2D vortices in a developing pulsed plasma jet
Get PDFTwo-dimensional vortex pairs were continuously generated by dielectric-barrier-discharge (DBD) pulsed plasma actuators, whose transformation to a free jet in the near field was investigated using a time-resolved particle image velocimetry (PIV) technique. At low modulation frequences, the plasma-induced vortex pairs developed into a free jet with little or no interactions. As the modulation frequency was increased, however, strong vortex interactions started taking place to initiate the leapfrogging, which continued every two plasma pulses. This helped sustain significant plasma-induced thrust further downstream. With a further increase in the modulation frequency, initial vortex pairs merged with a loss of jet thrust. In this study, these vortex interaction behaviours were carefully investigated using the wavelet spectral analysis as well as measured mean velocity and turbulent intensity profiles. Finally, the dynamics of leapfrogging vortex pairs and the mechanism of vortex merger initiation were investigated to depict the uniqueness in the 2D vortex interactions in a developing pulsed plasma jet
Facile synthesis of zeolitic imidazolate framework coated glass microspheres
Get PDFIn this study we report a facile one-step, room temperature synthetic methodology for fabricating ZIF-8-coated phosphate-based glass (PBG) microspheres. ZIF-8 was grown in situ onto solid (non-porous) and porous P40 glass microspheres (composition 20Na2O–24MgO–16CaO–40P2O5, average diameter 153–172 µm), confirmed by PXRD and SEM analyses, with reaction times of one hour sufficient for coating onto solid P40 microspheres. An extended reaction time of 4.5 hours resulted in more homogeneous ZIF-8 coverage on the porous P40 microspheres. The ZIF-8 layer reduced microsphere degradation in water and slowed ion release from the microspheres, demonstrating a sacrificial protective coating effect of the ZIF-8. The ZIF-8 layer also enabled Zn2+ release (6.9–13.6 ppm over 7 days) and demonstrated improved methylene blue loading capacity, showing promise for pH-responsive drug delivery. This adaptable synthetic method to produce P40-based MOF composites highlights the potential synergistic benefits of combining PBG microspheres (bioactivity, tuneable degradation rates) and MOFs (high surface areas and porosity), offering an underexplored strategy to new MOF@PBG composites for drug delivery, antibacterial coatings and bone repair
Archaeal G-quadruplexes: a novel model for understanding unusual DNA/RNA structures across the tree of life
Get PDFArchaea, a domain of microorganisms found in diverse environments, including the human microbiome, represent the closest known prokaryotic relatives of eukaryotes. This phylogenetic proximity positions them as a relevant model for investigating the evolutionary origins of nucleic acid secondary structures such as G-quadruplexes (G4s) which play regulatory roles in transcription and replication. Although G4s have been extensively studied in eukaryotes, their presence and function in archaea remain poorly characterized. In this study, a genome-wide analysis of the halophilic archaeon Haloferax volcanii identified over 5800 potential G4-forming sequences. Biophysical validation confirmed that many of these sequences adopt stable G4 conformations in vitro. Using G4-specific detection tools and super-resolution microscopy, G4 structures were visualized in vivo in both DNA and RNA across multiple growth phases. Comparable findings were observed in the thermophilic archaeon Thermococcus barophilus. Functional analysis using helicase-deficient H. volcanii strains further identified candidate enzymes involved in G4 resolution. These results establish H. volcanii as a tractable archaeal model for G4 biology
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