Browsing by Author "Grootveld, Martin"
Now showing 1 - 20 of 96
Results Per Page
Sort Options
Item Metadata only 1H NMR investigations of the molecular nature of cobalt (II) ions in human saliva(Elsevier, 2012) Chang, H.; Tomoda, S.; Silwood, C.; Lynch, E.; Grootveld, MartinHigh-resolution 1H NMR spectroscopy demonstrated that addition of Co(II) ions to isolated human salivary supernatants (HSSs) gave rise to its complexation by a variety of biomolecules. The relative efficacies of these complexants/chelators in this context were classifiable by the influence of added Co(II) on their line-widths and chemical shift values, and also the added Co(II) concentration-dependence of these spectral modifications. Those which were most affected by the addition of this metal ion were lactate > formate histidinate > succinate, this order reflecting the ability of these complexants to compete for the available Co(II) in terms of (1) thermodynamic equilibrium constants for the ormation of their complexes and (2) their HSS concentrations. Since many of these HSS Co(II) complexants (particularly lactate,formate and histidine) serve as powerful OH cavengers, the results acquired indicate that any of this radical generated from the Co(II) source in such complexes via pseudo-Fenton reactions may be ‘sitespecifically’ scavenged. The significance of these observations regarding the in vivo corrosion of cobaltcontaining metal alloy dental prostheses (e.g., Co–Cr alloys), the availability of trace levels of this metal ion in human saliva, and cobalt toxicity, is discussed.Item Open Access 1H NMR-based metabolomics reveals neurochemical alterations in the brain of adolescent rats following acute methylphenidate administration(Elsevier, 2017-03-06) Quansah, Emmanuel; Ruiz-Rodado, Victor; Grootveld, Martin; Probert, Fay; Zetterstrom, T. S. C.The psychostimulant methylphenidate (MPH) is increasingly used in the treatment of attention deficit hyperactivity disorder (ADHD). While there is little evidence for common brain pathology in ADHD, some studies suggest a right hemisphere dysfunction among people diagnosed with the condition. However, in spite of the high usage of MPH in children and adolescents, its mechanism of action is poorly understood. Given that MPH blocks the neuronal transporters for dopamine and noradrenaline, most research into the effects of MPH on the brain has largely focused on these two monoamine neurotransmitter systems. Interestingly, recent studies have demonstrated metabolic changes in the brain of ADHD patients, but the impact of MPH on endogenous brain metabolites remains unclear. In this study, a proton nuclear magnetic resonance (1H NMR)-based metabolomics approach was employed to investigate the effects of MPH on brain biomolecules. Adolescent male Sprague Dawley rats were injected intraperitoneally with MPH (5.0 mg/kg) or saline (1.0 ml/kg), and cerebral extracts from the left and right hemispheres were analysed. A total of 22 variables (representing 13 distinct metabolites) were significantly increased in the MPH-treated samples relative to the saline-treated controls. The upregulated metabolites included: amino acid neurotransmitters such as GABA, glutamate and aspartate; large neutral amino acids (LNAA), including the aromatic amino acids (AAA) tyrosine and phenylalanine, both of which are involved in the metabolism of dopamine and noradrenaline; and metabolites associated with energy and cell membrane dynamics, such as creatine and myo-inositol. No significant differences in metabolite concentrations were found between the left and right cerebral hemispheres. These findings provide new insights into the mechanisms of action of the anti-ADHD drug MPH.Item Open Access 1H NMR-Linked Metabolomics Analysis of Liver from a Mouse Model of NP-C1 Disease(AOCS, 2016-08-09) Ruiz-Rodado, Victor; Nicoli, Elena-Raluca; Probert, Fay; Smith, David A.; Morris, Lauren; Wassif, Christopher A.; Platt, Frances M.; Grootveld, MartinItem Metadata only 1H NMR-Linked Urinary Metabolic Profiling of Niemann-Pick Class C1 (NPC1) Disease: Identification of Potential New Biomarkers using Correlated Component Regression (CCR) and Genetic Algorithm (GA) Analysis Strategies(Bentham Science, 2014-11-14) Ruiz-Rodado, Victor; Luque-Baena, R. M.; te Vruchte, D. J.; Probert, Fay; Lachmann, R. H.; Hendriksz, Christian J.; Wraith, James E.; Imrie, Jackie; Elizondo, David; Sillence, Daniel J.; Clayton, P.; Platt, Frances M.; Grootveld, MartinNiemann-Pick Class 1 (NPC1) disease is a rare, debilitating neurodegenerative lysosomal storage disease; however, urinary biomarkers available for it and its prognosis are currently limited. In order to identify and establish such biomarkers, we employed high-resolution 1H NMR analysis coupled to a range of multivariate (MV) analysis approaches, i.e. PLS-DA, RFs and uniquely the cross-validated correlated component regression (CCR) strategy in order to discern differences between the urinary metabolic profiles of 13 untreated NPC1 disease and 47 heterozygous (parental) carrier control participants. Novel computational intelligence techniques (CITs) involving genetic algorithms (GAs) were also employed for this purposeItem Metadata only A spectrophotometric study on light attenuation properties of dental bleaching gels: potential relevance to irradiation parameters.(MDPI, 2020-12-16) Anagnostaki, E.; Mylona, V.; Parker, S.; Kosma, K.; Chala, M.; Cronshaw, M.; Dimitriou, V.; Tartarakis, M.; Papadogiannis, N.; Lynch, E.; Grootveld, MartinBackground: During in-office bleaching, appropriate light sources are applied in order to enhance the activity of the bleaching gels applied onto teeth. For this method to be effective, a high absorption of light within the gel is necessary. Variation in the light attenuation capability of the gel, the duration of application and light activation can contribute towards safety hazards associated with this procedure. Methods: In this study, seven different gels and hydrogen peroxide have been evaluated for their optical properties by means of spectrophotometry (440–1000 nm). The transmitted light spectrum was used to estimate the intensity loss for each gel. The mean intensity decreases observed were statistically analysed using an analysis of variance (ANOVA). Results: The five more-pigmented gels tested indicated a very similar intensity loss of around 80%, whereas the remaining two gels showed significantly less attenuation (predominantly, p < 10−6). Conclusions: Throughout the spectrum of wavelengths examined, and according to the underlying studies evaluated, five of the gels assessed demonstrated an attenuation high enough to possibly avoid overheating of the underlying enamel dentine and pulp. An evaluation of appropriate irradiation parameters is proposed.Item Metadata only A systematic literature review on the role of lasers in endodontic therapy: Valuable adjunct treatment?(MDPI, 2020-07-01) Anagnostaki, Eugenia; Mylona, Valina; Parker, Steven; Lynch, Edward; Grootveld, Martin(1) Background: Adjunctive instruments, such as lasers have been investigated to address the risk of failure of endodontic therapy due to the complexity of the root canal system. Lasers have been used therapeutically, in direct irradiation of the root canals or adjunct to irrigants placed into the canals, in combination with a photosensitizer (antimicrobial photodynamic therapy) and in pain management (photobiomodulation). The purpose of this systematic review was to evaluate the evidence in clinical use within these three areas of therapy. (2) Methods: PubMed, Cochrane and Scopus search engines were used to identify human clinical trials regarding the use of lasers in endodontic therapy. (3) Results: After applying the keywords and additional filters, inclusion and exclusion criteria, the initial number of 1486 articles was reduced to 17. It was revealed that almost all studies (14/17) presented a statistically significant improved outcome in laser-assisted endodontic therapy, with the remaining three not showing any adverse effects. (4) Conclusions: The use of laser photonic energy of appropriate delivered parameters can be proposed as useful adjunctive when considering optimal treatment modalities in orthograde endodontics. Additionally, a tendency of research towards pain modulation in this field is developing.Item Metadata only Antibacterial activity of textiles for wound treatment.(Association of Textile, Apparel & Materials Professionals, 2015) Pinho, Eva; Grootveld, Martin; Soares, Graça; Henriques, MarianaItem Metadata only Antimicrobial Activity of Ternary Essential Oil Mixtures in Topical Cosmetic Preparations Against Acne Vulgaris-Associated Bacteria.(Phytochemical Society of Europe, 2017) Owen, Lucy; Grootveld, Martin; Arroo, R. R. J.; Ruiz-Rodado, Victor; Price, Penny; Laird, KatieAcne vulgaris is a chronic skin condition associated with overgrowth of Propionibacterium acnes and Staphylococcus epidermidis. Antibiotics are commonly prescribed to control acne; however, resistance has emerged, indicating the need for new antimicrobial therapies1. Several essential oils (EOs) are antimicrobial, including against antibiotic-resistant isolates, indicating that antimicrobial formulations may be developed using EOs2. The aim of this study was to develop a topical preparation incorporating EOs to control acne-associated bacteria, and compare its efficacy with the topical antibiotic formulations Dalacin T® and Stiemycin®. The antimicrobial activity of litsea (Litsea cubeba), rosewood (Aniba rosaeadora) and clove bud (Syzigum aromaticum) EOs was identified using the Kirby-Bauer disc diffusion method3 and the minimum inhibitory concentrations (MICs) were determined using a broth microdilution assay3.The MICs of clove bud and rosewood were 1.38 mg/ml against S. epidermidis and P. acnes. The MIC of litsea was 1.11 mg/mL against S. epidermidis and 2.23 mg/mL against P. acnes. The antimicrobial activity of a ternary combination of these EOs was further investigated using the checkerboard method with calculation of fractional inhibitory concentration index (FICI)4. Synergy was observed against both test species (FICI < 0.5). The EOs were characterised by both GC-MS and NMR. The antimicrobial efficacy of a cosmetic preparation containing the ternary EO combination was then compared to that of the current prescription medicines Dalacin T® and Stiemycin®. A combination of 0.53 mg/mL litsea, 0.11 mg/mL rosewood and 0.11 mg/mL clove bud EOs was formulated into a neroli herbal distillate with 0.5% (v/v) ethanol. Survival of P. acnes and S. epidermidis (types and clinical isolates) after a 24 h contact with the formulations was determined and compared to Dalacin T® and Stiemycin®. The formulation completely inhibited P. acnes (7 log10 reduction) and S. epidermidis (6 log10 reduction), and was equivalent in activity to Dalacin T® and Stiemycin®, including erythromycin-resistant isolates. The EO combination alone was either more antimicrobial (p ≤ 0.05) or equivalent in activity to the active ingredients of Dalacin T® and Stiemycin® (10 mg/mL clindamycin phosphate and 20 mg/mL erythromycin, respectively). The formulation may be useful as an alternative to antibiotic preparations for the control of acne-associated bacteria.Item Open Access Application of a Novel Tongue Resin Replication(Science Domain International, 2016-09-08) Bernardi, S.; Grootveld, Martin; Tejpal, Jyoti; Laird, KatieAims: Biofilms present a strategy for microorganisms to survive and resist adverse conditions. In order to further our understanding of this resistance mechanism, it is of much importance to develop new methodologies in order to assess such biofilm activities. One of the most defined biofilms is dental plaque. However, the oral cavity contains a different class of biofilm, the precise structural nature of which is dependent on its site of development. Indeed, tongue-coated biofilms have remained a focus for in vitro studies, especially since they represent the major source of oral malodor. The aim of this research was to investigate the growth of a biofilm on a tongue replication constructed from a resin material, and its use in further experimental investigations. Methods: The model used for this study involved an adapted CDC biofilm reactor in order to achieve this; Staphylococcus aureus was used as the test organism. Results: Biofilm culturing techniques employed demonstrated a positive growth from the microbes retrieved from the tongue-impressed resin material. Moreover, results acquired confirmed that theresin-based tongue replication harbored significantly greater levels of S. aureus than those of unimpressed resin, plastic and stainless steel controls. Conclusions: Therefore, this study provides evidence that the employment of a CDC biofilm reactor in combination with a resin tongue device creates an oral biofilm model which provides valuable information regarding our understanding of how the roughnessItem Metadata only Application of data augmentation techniques towards metabolomics(Elsevier, 2022-07-27) Elizondo, David; Grootveld, Martin; Moreno-Barea, Francisco J.; Franco, LeonardoNiemann–Pick Class 1 (NPC1) disease is a rare and debilitating neurodegenerative lysosomal storage disease (LSD). Metabolomics datasets of NPC1 patients available to perform this type of analysis are often limited in the number of samples and severely unbalanced. In order to improve the predictive capability and identify new biomarkers in an NPC1 disease urinary dataset, data augmentation (DA) techniques based on computational intelligence have been employed to create synthetic samples, i.e. the addition of noise, oversampling techniques and conditional generative adversarial networks. These techniques have been used to evaluate their predictive capacities on a set of urine samples donated by 13 untreated NPC1 disease and 47 heterozygous (parental) carrier control participants. Results on the prediction have also been obtained using different machine learning classification models and the partial least squares techniques. These results provide strong evidence for the ability of DA techniques to generate good quality synthetic data. Results acquired show increases in sensitivity of 20%–50%, an F1 score of 6%–30%, and a predictive capacity of 0.3 (out of 1). Additionally, more conventional forms of multivariate data analysis have been employed. These have allowed the detection of unusual urinary metabolite profiles, and the identification of biomarkers through the use of synthetically augmented datasets. Results indicate that urinary branched-chain amino acids such as valine, 3-aminoisobutyrate and quinolinate, may be employable as valuable biomarkers for the diagnosis and prognostic monitoring of NPC1 disease.Item Metadata only Assessing the viability of laser-activated dental bleaching compared to conventional in-office bleaching methods: A systematic review of clinical and in vitro studies.(MDPI, 2023-11-17) Anagnostaki, Eugenia; Mylona, Valina; Parker, Steven; Cronshaw, Mark; Grootveld, MartinLaser-activated tooth bleaching is discussed as a means to optimize results, while minimizing adverse side effects, but it lacks consensus in the scientific literature. Therefore, this systematic review aims to evaluate the protocols and outcomes of laser-activated vs. non-activated bleaching methods for safe and effective approaches. The PubMed, Cochrane, Scopus, ScienceDirect, and Google Scholar search engines, with the following MeSH terms and keywords: (bleaching OR whitening) AND laser AND (tooth OR dental OR enamel OR dentine), were used to identify human clinical trials and in vitro studies regarding laser-activated dental bleaching. After applying the keywords and additional filters, and inclusion and exclusion criteria, the final number of included articles was 19 clinical and 20 in vitro studies. Laser activation yielded no significant color improvement, but reduced gel contact time (10 min). Laser-activated bleaching required 24% less hydrogen peroxide (HP) concentration to achieve similar results. Additionally, there were no significant differences in terms of sensitivity and hard tissue alterations between the laser-activated and conventional groups. The benefits associated with laser-activated bleaching render it a compelling option. Nevertheless, a comprehensive evaluation of bleaching gels and activation protocols is imperative. Ultimately, this analysis provides clinical guidance pertaining to the facilitatory employment of laser irradiation.Item Metadata only Benchtop Low-Frequency 60 MHz NMR Analysis of Urine: A Comparative Metabolomics Investigation(MDPI, 2020-04-16) Leenders, Justine; Grootveld, Martin; Percival, Benita; Gibson, Miles; Casanova, Federico; Wilson, Philippe B.Metabolomics techniques are now applied in numerous fields, with the ability to provide information concerning a large number of metabolites from a single sample in a short timeframe. Although high-frequency (HF) nuclear magnetic resonance (NMR) analysis represents a common method of choice to perform such studies, few investigations employing low-frequency (LF) NMR spectrometers have yet been published. Herein, we apply and contrast LF and HF 1H-NMR metabolomics approaches to the study of urine samples collected from type 2 diabetic patients (T2D), and apply a comparative investigation with healthy controls. Additionally, we explore the capabilities of LF 1H-1H 2D correlation spectroscopy (COSY) experiments regarding the determination of metabolites, their resolution and associated analyses in human urine samples. T2D samples were readily distinguishable from controls, with several metabolites, particularly glucose, being associated with this distinction. Comparable results were obtained with HF and LF spectrometers. Linear correlation analyses were performed to derive relationships between the intensities of 1D and 2D resonances of several metabolites, and R2 values obtained were able to confirm these, an observation attesting to the validity of employing 2D LF experiments for future applications in metabolomics studies. Our data suggest that LF spectrometers may prove to be easy-to-use, compact and inexpensive tools to perform routine metabolomics analyses in laboratories and ‘point-of-care’ sites. Furthermore, the quality of 2D spectra obtained from these instruments in half an hour would broaden the horizon of their potential applications.Item Open Access Benchtop NMR Spectroscopy and Spectral Analysis of the cis- and trans-Stilbene Products of the Wittig Reaction(ACS, 2019-07-16) Edgar, Mark; Percival, Benita; Gibson, Miles; Masania, Jinit; Beresford, Ken; Wilson, Philippe B.; Grootveld, MartinBenchtop NMR spectrometers are now becoming more widely employed in university teaching laboratories. These low-field instruments are increasingly used in reaction monitoring and product purity applications. NMR spectra obtained using these spectrometers (40–80 MHz) tend to suffer from significant overlap of signals when compared to those obtained at 300–400 MHz or above, and therefore, some reactions may be less suited to analysis using such benchtop systems. While some reactions can be modified to make them more amenable to analysis on low-field benchtop spectrometers, the fact remains that many common undergraduate laboratory chemistry reactions remain as a stalwart of the university education system. Therefore, there is currently a major requirement for benchtop NMR analysis to improve in order to facilitate student understanding. Herein, it is demonstrated that a combination of spectral analysis and simulation at low-fields (40–80 MHz) allows the fine structure of second-order effects and overlapping spectra to be deduced, enabling an improved understanding of the low-field benchtop NMR technique within undergraduate student cohorts. The evolution of well-resolved and distinct multiplets at 400 MHz to complex, overlapping multiplets at 40–80 MHz also serves as a useful guide for laboratory demonstrators and academic staff when explaining the advantages of such benchtop systems. The Wittig reaction has been a standard reaction practical session in many university teaching laboratories since the 1980s, the products of which are a mixture of cis- and trans-stilbenes. This reaction serves as an ideal example of how benchtop NMR spectrometers and analysis can support chemistry teaching laboratories.Item Open Access Characterisation of Actions of p-menthane-3,8 diol (PMD) Repellent Formulations against Aedes aegypti mosquitoes(Oxford University Press, 2020-06-15) Goodyer, Larry; Grootveld, Martin; Deobhankar, Kedar; Debboun, Mustapha; Philip, ManjuBackground Characterisation of mosquito repellents using arm-in-cage tests are performed by assessing the ED95, half-life and complete protection times (CPT). This study fully characterises p-menthane-3,8 diol PMD which has not been widely studied, and a long-acting formulation containing a PMD-vanillin composite. Method A series of arm in cage tests against Aedes aegypti aegypti (Dipera-Culicidae) strain mosquitoes were devised using 6 volunteers to estimate CPT or 10 to estimate the effective dose (ED95) and half-life for three repellents: 20% DEET, 30% PMD and a novel 30% PMD-vanillin formulation. Non-linear Regression analysis was used to characterise the relationship between applied dose and CPT. were also estimated Results PMD and DEET showed a very similar log dose relationship to CPT; however, the PMD-vanillin formulation exhibited a sigmoidal ‘S-shape’ relationship. This resulted in a 1.5 times higher CPT for PMD-vanillin compared to that of 20% DEET when applied at a dose of 1.6mg/cm2, but little difference at lower doses of 0.8-1mg/cm2. The ED95 value for the 30% PMD and PMD-vanillin formulations were 0.25 and 0.24 mg/cm2 respectively, these being higher than that for 20% DEET (0.09 mg/cm2). The half-lives for 30% PMD and 20% DEET were similar (2.23 vs. 2.74 hrs.), but longer for the PMD-vanillin formulations (3.8 hrs.). Conclusion Such a full characterisation for other repellent formulations, particularly those claiming extended longevity, should be conducted in order to identify differences at various applied doses.Item Metadata only Chemometric analysis of the consumption of oral rinse chlorite (ClO2 -) by human salivary biomolecules.(Springer, 2013) Chang, H.; Blackburn, J.; Grootveld, MartinItem Metadata only Chemometric variance analysis of 1H NMR metabolomics data on the effects of oral rinse on saliva(Springer, 2012) Lemanska, A.; Grootveld, Martin; Silwood, C.; Brereton, R.Saliva is an easy to obtain bodily fluid that is specific to the oral environment. It can be used for metabolomic studies as it is representative of the overall wellbeing of an organism, as well as mouth health and bacterial flora. The metabolomic structure of saliva varies greatly depending on the bacteria present in the mouth as they produce a range of metabolites. In this study we have investigated the metabolomic profiles of human saliva that were obtained using 1H NMR (nuclear magnetic resonance) analysis. 48 samples of saliva were collected from 16 healthy subjects over 3 days. Each sample was split in two and the first half treated with an oral rinse, while the second was left untreated as a control sample. The 96 1H NMR metabolomic profiles obtained in the dataset are affected by three factors, namely 16 subjects, 3 sampling days and 2 treatments. These three factors contribute to the total variation in the dataset. When analysing datasets from saliva using traditional methods such as PCA (principal component analysis), the overall variance is dominated by subjects’ contributions, and we cannot see trends that would highlight the effect of specific factors such as oral rinse. In order to identify these trends, we used methods such as MSCA (multilevel simultaneous component analysis) and ASCA (ANOVA simultaneous component analysis), that provide variance splits according to the experimental factors, so that we could look at the particular effect of treatment on saliva. The analysis of the treatment effect was enhanced, as it was isolated from the overall variance and assessed without confounding factors.Item Open Access Chronic Non-Communicable Disease Risks Presented by Lipid Oxidation Products in Fried Foods(AME, 2018) Grootveld, Martin; Percival, B. C.; Grootveld, KerryExposure of UFA-containing culinary frying oils (CFOs), especially PUFA-rich ones, to high temperature frying episodes produces substantial, highly toxicologically-significant concentrations of reactive aldehydes, together with additional lipid oxidation products (LOPs), via a complex series of oxidative recycling bursts. Migration of thermally-stressed, peroxidised frying oils into foods during standard frying practices renders such LOP toxins available for human consumption, and concentrations of trans-2-alkenals, trans,trans-alka-2,4-dienals and n-alkanals present in potato chips obtained from fast-food retailers and further food outlets are all much greater than those of acrylamide and monochloropropanediol adducts detectable, for which a verisimilitude of high level public health concerns have been repeatedly stressed in the scientific literature available. In view of our observations, such LOPs are likely to play pivotal roles regarding the development, progression and incidence of wide range of human non-communicable diseases (NCDs), which undoubtedly will promote rising healthcare costs worldwide. Indeed, 30-35% of human cancers arising from environmental sources are attributable to diet alone, and it is therefore highly conceivable that dietary LOPs may impact significantly on this incidence level. Hence, exacting efforts to limit the consumption of foods fried in CFOs with high LOP contents are required. Since CFOs rich in peroxidation-resistant MUFAs, and especially SFAs, produce lower and much lower levels of such LOP toxins during frying episodes respectively, they offer safer, health-friendly alternatives to those laden with PUFAs. However, the future consideration, establishment and ratification of currently-unavailable minimal human daily intakes for LOPs of known molecular identities also represent major demands for action. Consumer concerns regarding the nutritional and health properties of their foods strongly support such requirements.Item Metadata only Comparative 1H NMR-Based Chemometric Evaluations of the Time-Dependent Generation of Aldehydic Lipid Oxidation Products in Culinary Oils Exposed to Laboratory-Simulated Shallow Frying Episodes: Differential Patterns Observed for Omega-3 Fatty Acid-Containing Soybean Oils(MDPI, 2021-10-17) Wann, Angela; Percival, Benita; Woodason, Kate; Gibson, Miles; Vincent, Siany; Grootveld, MartinSoybean oil is the second most exported oil from the United States and South America, and is widely marketed as a cooking oil product containing numerous health benefits for human consumers. However, culinary oils with high polyunsaturated fatty acid (PUFA) contents, are known to produce high quantities of lipid oxidation products (LOPs), including toxic aldehydes upon exposure to high-temperature frying episodes. Previous studies have demonstrated causal links between aldehyde ingestion and inhalation with deleterious health perturbations, including mutagenic and carcinogenic effects, along with cardiovascular and teratogenic actions. In this study, aldehydic LOPs were detected and quantified in commercially available samples of soybean, avocado, corn and extra-virgin olive oil products before and after their exposure to laboratory-simulated laboratory frying episodes (LSSFEs) using high-resolution 1H nuclear magnetic resonance (NMR) analysis. Results acquired demonstrated that PUFA-rich soybean and corn oils gave rise to the highest concentrations of oil aldehydes from the thermo-oxidation of unsaturated fatty acids, whereas monounsaturated fatty acid (MUFA)-laden avocado and olive oils were much more resistant to this peroxidation process, as expected. Multivariate chemometrics analyses provided evidence that an orthogonal component pattern of aldehydic LOPs featuring low-molecular-mass n-alkanals such as propanal, and 4-oxo-alkanals, arises from thermo-oxidation of the ω-3 fatty acid (FA) linolenic acid (present in soybean oils at levels of ca. 7% (w/w)), was able to at least partially distinguish this oil from corresponding samples of thermally-stressed corn oil. Despite having a similar total PUFA level, corn oil has only a negligible ω-3 FA content, and therefore generated significantly lower levels of these two aldehyde classes. In view of the adverse health effects associated with dietary LOP ingestion, alternative methodologies for the incorporation of soybean oils within high-temperature frying practices are proposed.Item Metadata only Computational intelligence techniques in medicine.(Hindawi, 2014) López-Rubio, Ezequiel; Elizondo, David; Grootveld, Martin; Jerez, Jose; Luque-Baena, Rafael MarcosItem Open Access Computational Simulation of 1H NMR Profiles of Complex Biofluid Analyte Mixtures at Differential Operating Frequencies: Applications to Low-Field Benchtop Spectra(Wiley, 2021-11-30) Edgar, Mark; Kuhn, Stefan; Page, Georgina; Grootveld, MartinEstimations of accurate and reliable NMR chemical shift values, coupling patterns and constants within a reasonable timeframe remain significantly challenging, and the unavailability of reliable software strategies for the prediction of low-field (e.g., 60 MHz) spectra from those acquired at higher operating frequencies hampers their direct comparison. Hence, this study explored the applications of accessible software options for predicting these parameters in the 1H NMR profiles of analytes as a function of magnetic field strength; this was performed for individual analytes and also for complex biofluid matrices featured in metabolomics investigations. For this purpose, results from the very first successful experimental acquisition and simulation of the 1H NMR profiles of intact human salivary supernatant samples on a 60 MHz benchtop spectrometer were evaluated. Using salivary metabolite concentrations determined at 400 MHz, it was demonstrated that simulation of the low-field spectra of five biomolecules with the most prominent 1H resonances detectable allowed multiple component fits to be applied to experimental spectra. Hence, these salivary 1H NMR profiles could be successfully predicted throughout the 45–600 MHz operating frequency range. With the exception of propionate resonance multiplets, which revealed more complex coupling patterns at low field and required more astute computational and fitting options, valuable quantitative metabolomics data on salivary acetate, formate, methanol and glycine could be attained from low-field spectrometres. These studies are both timely and pertinent in view of the recent advancement of low-field benchtop NMR facilities for diagnostically significant biomarker tracking in biofluids. Experiments performed with added ammonium chloride to facilitate the release of salivary metabolites from biopolymer binding sites provided evidence that a small but nevertheless significant proportion of propionate, but not lactate, was bound to such sites, an observation of much relevance to biomolecule quantification in salivary metabolomics investigations.