Levels of lipid-derived gut microbial metabolites differ among plant matrices in an in vitro model of colon fermentation

This study explored differences in microbial lipid metabolites among sunflower seeds, soybeans, and walnuts. The matrices were subjected to in vitro digestion and colonic fermentation. Defatted digested materials and fiber/phenolics extracted therefrom were added to sunflower oil (SO) and also fermented. Targeted and untargeted lipidomics were employed to monitor and tentatively identify linoleic acid (LA) metabolites. Walnut fermentation produced the highest free fatty acids (FFAs), LA, and conjugated LAs (CLAs). Defatted digested walnuts added to SO boosted FFAs and CLAs production; the addition of fibre boosted CLAs, whereas the addition of phenolics only increased 9e,11z-CLA and 10e,12z-CLA. Several di-/tri-hydroxy-C18-FAs, reported as microbial LA metabolites for the first time, were annotated. Permutational multivariate analysis of variance indicated significant impacts of food matrix presence and type on lipidomics and C18-FAs. Our findings highlight how the food matrices affect CLA production from dietary lipids, emphasizing the role of food context in microbial lipid metabolism

Eating fermented: Health benefits of lab-fermented foods

Lactic acid bacteria (LAB) are involved in producing a considerable number of fermented products consumed worldwide. Many of those LAB fermented foods are recognized as beneficial for human health due to probiotic LAB or their metabolites produced during food fermentation or after food digestion. In this review, we aim to gather and discuss available information on the health-related effects of LAB-fermented foods. In particular, we focused on the most widely consumed LAB-fermented foods such as yoghurt, kefir, cheese, and plant-based products such as sauerkrauts and kimchi

Levelised cost of energy: a theoretical justification and critical assessment.

Although widely accepted as a measure of the comparative lifetime costs of electricity generation alternatives, levelised cost of energy (LCOE) lacks a theoretical foundation in the academic literature and encompasses a number of areas where caution is important. Therefore, this paper seeks to provide a theoretical foundation by comparing the metric with alternative LCOE metrics and by undertaking a brief literature review to describe its strengths and weaknesses. In comparison with other potential measures of unit cost of energy, LCOE is found to be the preferred choice, in large part because of its widespread adoption. The weaknesses of the LCOE are found to centre on discount rate, inflation effects and the sensitivity of results to uncertainty in future commodity costs. These weaknesses are explored in the context of comparing combined cycle gas fired generation and offshore wind in the UK, based on publicly available cost measures. It is found that with variability of future fuel gas prices, and a Monte Carlo approach to modelling LCOE, the range of LCOE for CCGT is much broader in comparison to the LCOE of offshore wind. It is urged that explicit account be taken of the areas of weakness in future use of LCOE

Comparison of epoxy and braze-welded attachment methods for FBG strain gauges

This paper presents experimental results from fatigue and static loading tests performed on both epoxy and braze-welded FBG strain sensors. Most FBG attachment methods are relatively understudied, with epoxy the most commonly used. Long curing times and humidity sensitivity during curing render epoxy inappropriate for certain implementations. This work shows that a bespoke braze-welded attachment design is able to achieve a higher static failure limit of 22kN when compared to strain gauge epoxies, which fail at 20kN. Both methods demonstrate high fatigue life, with no significant deterioration after two million cycles. Epoxy swelling was observed when the sensors were held at a relative humidity of 96%, applying ~0.6 mϵ of tension to the FBG, whereas a braze-weld attachment was unaffected by humidity

Wind turbine lifetime extension decision-making based on structural health monitoring

In this work, structural health monitoring data is applied to underpin a long-term wind farm lifetime extension strategy. Based on the outcome of the technical analysis, the case for an extended lifetime of 15 years is argued. Having established the lifetime extension strategy, the single wind turbine investigated within a wind farm is subjected to a bespoke economic lifetime extension case study. In this case study, the local wind resource is taken into consideration, paired with central, optimistic, and pessimistic operational cost assumptions. Besides a deterministic approach, a stochastic analysis is carried out based on Monte Carlo simulations of selected scenarios. Findings reveal the economic potential to operate profitably in a subsidy-free environment with a P90 levelised cost of energy of £25.02 if no component replacement is required within the nacelle and £42.53 for a complete replacement of blades, generator, and gearbox

Lipid complexation reduces rice starch digestibility and boosts short-chain fatty acid production via gut microbiota

In this study, two rice varieties (RS4 and GZ93) with different amylose and lipid contents were studied, and their starch was used to prepare starch-palmitic acid complexes. The RS4 samples showed a significantly higher lipid content in their flour, starch, and complex samples compared to GZ93. The static in vitro digestion highlighted that RS4 samples had significantly lower digestibility than the GZ93 samples. The C∞ of the starch-lipid complex samples was found to be 17.7% and 18.5% lower than that of the starch samples in GZ93 and RS4, respectively. The INFOGEST undigested fractions were subsequently used for in vitro colonic fermentation. Short-chain fatty acids (SCFAs) concentrations, mainly acetate, and propionate were significantly higher in starch-lipid complexes compared to native flour or starch samples. Starch-lipid complexes produced a distinctive microbial composition, which resulted in different gene functions, mainly related to pyruvate, fructose, and mannose metabolism. Using Model-based Integration of Metabolite Observations and Species Abundances 2 (MIMOSA2), SCFA production was predicted and associated with the gut microbiota. These results indicated that incorporating lipids into rice starch promotes SCFA production by modulating the gut microbiota selectively

On-line tracking of the human gut microbial metabolism: high-throughput screening during colonic in-vitro fermentation

The human gut encloses a large community of bacteria producing a wide range of volatile organic compounds (VOCs) when fermenting undigestible substrates. This study aims to provide a high throughput method to study in real-time the gut microbial volatilome when the microbiota process undigestible dietary substrates. Background: Small metabolites from the human gut microbiota are recognized as the intermediates of the microbiome-host cross-talk [1]. The research on the human gut metabolome is mainly based on discrete sampling representing discontinuous ‘snapshot’ of these complex biological systems [2]. The aim of this research work is to enhance the current understanding of the dynamics of the gut microbiota by integrating non-invasive and continuous analytical methods with in-vitro gut simulators, to monitor in real-time, the progression of small molecules released into the headspace [2,3] Methodology: Automated Head space-Solid Phase Micro Extraction coupled with Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS) and Static Headspace- Proton Transfer Reaction-Time of Flight-Mass Spectrometry (SHS-PTR-ToF-MS) are used for the purpose of this investigation. The objective is to screen and monitor a specific set of masses of interest, to gain system level mechanistic insights on primary metabolism of the gut microbial consortia. Results: This methodology enabled the continuous monitoring of multiple metabolites in time, including short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) derived from 24h oat bran fermentation. A mixture of -odd and -even chain acids were co-released into the culture headspace after 4 hours of fermentation and their relative abundance increased in time over 24 hours. The production of multiple MCFAs from the substrate is most likely a community optimization strategy to maximize ATP production from oat degradation by means of reverse beta-oxidation which involves the utilization of fermentation intermediates, such as propanol and acetate. Furthermore, the untargeted screening allowed the detection of low abundant sulfur metabolites, thiophenes, which, to our knowledge, were never investigated before as gut microbial metabolites (GMMs). Conclusion: By integrating non-invasive and continuous analytical methods with an in-vitro gut simulator, it was possible to monitor in real-time the progression of two important class of small molecules released by the microbial consortia into the headspace. The collected information can be jointly integrated to shed light on the dynamics of bacterial foraging of complex undigestible substrates (e.g. bran from cereals). Overall, these results confirm the idea to consider the bacterial headspace as a highly dynamic chemical system that contains information on microbial community behavio

Cognitive abilities that predict success in a computer-based training program.

PURPOSE: The purposes of this study were (a) to identify cognitive abilities and other factors related to successful completion of training for computer-based tasks that simulated real jobs and (b) to create a brief assessment battery useful in assessing older adults for these kinds of jobs. DESIGN AND METHODS: Participants from three age groups (young, middle-aged, and older) completed a battery of cognitive measures. They then trained on one of three computer-based tasks that simulated actual jobs and were asked to perform the tasks for 3 days. We recorded whether they completed training and whether and how well they did the tasks. In a series of logistic regressions, we evaluated the ability of a subset of cognitive measures drawn from a larger battery to predict participants\u27 ability to successfully complete training and go on to task performance. RESULTS: Results confirmed theory-based expectations that measures of domain knowledge, crystallized intelligence, memory, and psychomotor speed would predict success in computer-based activities. A brief battery was able to predict older adults\u27 successful completion of training for one task but was less useful for another. IMPLICATIONS: A brief battery of cognitive measures may be useful in evaluating individuals for job selection. Different measures are related to job-related criteria depending on task and group evaluated, although it was not possible to identify a reduced battery for one task. The specific cognitive abilities related to participants\u27 success have implications for task and interface design for the elderly population

Mejora del comportamiento en la extrusión de pastas cerámicas de baja plasticidad.

Shaping by extrusion may be used for the manufacture of tiles, bricks, and also refractory products. The three fundamental aspects that must be considered to achieve ideal extrusion conditions are the nature of the material, particle size and Plastic behaviour. Of these, obtaining a mass of adequate plasticity is essential during the processing in order to prevent defects such as cracks, laminations or migrations of the liquid phase [1]. Plastic behaviour depends on numerous factors [2]: size and shape of the particle, mineralogical composition, presence of electrolytes, organic matter, etc. With regard to traditional ceramics, as is the case of the manufacture of ceramic tiles, clay materials are those with the necessary plasticity to carry out the extrusion process. However, in the absence of clays with sufficient plasticity or when the composition incorporates a high proportion of other non-plastic ingredients, the extrusion operation may be seriously compromised, particularly for the manufacture of large or complex tiles. In these cases it is necessary to add plasticizers or binders to the pastes to achieve rheological behaviour and plasticity enabling correct processing of the composition [3]. In this report the influence of different additives in different proportions on the plasticity index of a ceramic composition was evaluated and the variation of the plasticity index was related to the behaviour of the paste during extrusion.El conformado por extrusión se puede utilizar para la fabricación de baldosas, ladrillos, tejas o también productos refractarios. Los tres aspectos fundamentales que se deben considerar para lograr unas condiciones de extrusión idóneas son la naturaleza del material, el tamaño de partícula y el comportamiento plástico. De éstas, obtener una masa de plasticidad adecuada es fundamental durante el procesado, para evitar la aparición de defectos tales como grietas, laminaciones o migraciones de la fase líquida [1]. El comportamiento plástico depende de numerosos factores [2]: tamaño y forma de la partícula, composición mineralógica, presencia de electrolitos, materia orgánica, etc. En lo que concierne a las cerámicas tradicionales, como es el caso de la fabricación de baldosas cerámicas, los materiales arcillosos son los que confieren la plasticidad necesaria para llevar a cabo el proceso de extrusión. Sin embargo, cuando no se dispone de arcillas con la plasticidad suficiente o cuando la composición incorpora otros ingredientes no plásticos en elevada proporción, la operación de extrusión se puede ver seriamente comprometida, sobre todo en la fabricación de baldosas de gran formato o de geometría compleja. En estos casos es necesario añadir a las pastas aditivos plastificantes o ligantes para conseguir un comportamiento reológico y plasticidad que permitan un correcto procesado de la composición [3]. En este trabajo se evaluó la influencia de la incorporación de diferentes aditivos en distintas proporciones sobre el índice de plasticidad de una composición cerámica y se relacionó la variación del índice de plasticidad con el comportamiento de la pasta durante la extrusión