Early life vitamin D depletion alters the postnatal response to skeletal loading in growing and mature bone

There is increasing evidence of persistent effects of early life vitamin D exposure on later skeletal health; linking low levels in early life to smaller bone size in childhood as well as increased fracture risk later in adulthood, independently of later vitamin D status. A major determinant of bone mass acquisition across all ages is mechanical loading. We tested the hypothesis in an animal model system that early life vitamin D depletion results in abrogation of the response to mechanical loading, with consequent reduction in bone size, mass and strength during both childhood and adulthood. A murine model was created in which pregnant dams were either vitamin D deficient or replete, and their offspring moved to a vitamin D replete diet at weaning. Tibias of the offspring were mechanically loaded and bone structure, extrinsic strength and growth measured both during growth and after skeletal maturity. Offspring of vitamin D deplete mice demonstrated lower bone mass in the non loaded limb and reduced bone mass accrual in response to loading in both the growing skeleton and after skeletal maturity. Early life vitamin D depletion led to reduced bone strength and altered bone biomechanical properties. These findings suggest early life vitamin D status may, in part, determine the propensity to osteoporosis and fracture that blights later life in many individuals

New framework for automated article selection applied to a literature review of Enhanced Biological Phosphorus Removal.

AimsEnhanced Biological Phosphorus Removal (EBPR) is a technology widely used in wastewater treatment to remove phosphorus (P) and prevent eutrophication. Establishing its operating efficiency and stability is an active research field that has generated almost 3000 publications in the last 40 years. Due to its size, including over 119 review articles, it is an example of a field where it becomes increasingly difficult to manually recognize its key research contributions, especially for non-experts or newcomers. Therefore, this work included two distinct but complementary objectives. First, to assemble for the first time a collection of bibliometric techniques into a framework for automating the article selection process when preparing a literature review (section 2). Second, to demonstrate it by applying it to the field of EBPR, producing a bibliometric analysis and a review of the key findings of EBPR research over time (section 3).FindingsThe joint analysis of citation networks, keywords, citation profiles, as well as of specific benchmarks for the identification of highly-cited publications revealed 12 research topics. Their content and evolution could be manually reviewed using a selection of articles consisting of approximately only 5% of the original set of publications. The largest topics addressed the identification of relevant microorganisms, the characterization of their metabolism, including denitrification and the competition between them (Clusters A-D). Emerging and influential topics, as determined by different citation indicators and temporal analysis, were related to volatile fatty acid production, P-recovery from waste activated sludge and aerobic granules for better process efficiency and stability (Clusters F-H).ConclusionsThe framework enabled key contributions in each of the constituent topics to be highlighted in a way that may have otherwise been biased by conventional citation-based ranking. Further, it reduced the need for manual input and a priori expertise compared to a traditional literature review. Hence, in an era of accelerated production of information and publications, this work contributed to the way that we are able to use computer-aided approaches to curate information and manage knowledge

Medium Chain Carboxylic Acids from Complex Organic Feedstocks by Mixed Culture Fermentation

Environmental pressures caused by population growth and consumerism require the development of resource recovery from waste, hence a circular economy approach. The production of chemicals and fuels from organic waste using mixed microbial cultures (MMC) has become promising. MMC use the synergy of bio-catalytic activities from different microorganisms to transform complex organic feedstock, such as by-products from food production and food waste. In the absence of oxygen, the feedstock can be converted into biogas through the established anaerobic digestion (AD) approach. The potential of MMC has shifted to production of intermediate AD compounds as precursors for renewable chemicals. A particular set of anaerobic pathways in MMC fermentation, known as chain elongation, can occur under specific conditions producing medium chain carboxylic acids (MCCAs) with higher value than biogas and broader applicability. This review introduces the chain elongation pathway and other bio-reactions occurring during MMC fermentation. We present an overview of the complex feedstocks used, and pinpoint the main operational parameters for MCCAs production such as temperature, pH, loading rates, inoculum, head space composition, and reactor design. The review evaluates the key findings of MCCA production using MMC, and concludes by identifying critical research targets to drive forward this promising technology as a valorisation method for complex organic waste

A novel metabolic-ASM model for full-scale biological nutrient removal systems

This study demonstrates that META-ASM, a new integrated metabolic activated sludge model, provides an overall platform to describe the activity of the key organisms and processes relevant to biological nutrient removal (BNR) systems with a robust single-set of default parameters. This model overcomes various shortcomings of existing enhanced biological phosphorous removal (EBPR) models studied over the last twenty years. The model has been tested against 34 data sets from enriched lab polyphosphate accumulating organism (PAO)-glycogen accumulating organism (GAO) cultures and experiments with full-scale sludge from five water resource recovery facilities (WRRFs) with two different process configurations: three stage Phoredox (A2/O) and adapted Biodenitro™ combined with a return sludge sidestream hydrolysis tank (RSS). Special attention is given to the operational conditions affecting the competition between PAOs and GAOs, capability of PAOs and GAOs to denitrify, metabolic shifts as a function of storage polymer concentrations, as well as the role of these polymers in endogenous processes and fermentation. The overall good correlations obtained between the predicted versus measured EBPR profiles from different data sets support that this new model, which is based on in-depth understanding of EBPR, reduces calibration efforts. On the other hand, the performance comparison between META-ASM and literature models demonstrates that existing literature models require extensive parameter changes and have limited predictive power, especially in the prediction of long-term EBPR performance. The development of such a model able to describe in detail the microbial and chemical transformations of BNR systems with minimal adjustment to parameters suggests that the META-ASM model is a powerful tool to predict and mitigate EBPR upsets, optimise EBPR performance and to evaluate new process designs

Optimisation of glycogen quantification in mixed microbial cultures

This study addressed the key factors affecting the extraction and quantification of glycogen from floccular and granular mixed microbial cultures collected from activated sludge, nutrient removal systems and photosynthetic consortiums: acid concentration, hydrolysis time and concentration of biomass in the hydrolysis. Response surface modelling indicated that 0.9M HCl and a biomass concentration of 1mgmL were optimal conditions for performing acid hydrolysis. Floccular samples only needed a 2-h hydrolysis time whereas granular samples required as much as 5h. An intermediate 3h yielded an error of 10% compared to the results obtained with the hydrolysis times specifically tailored to the type of biomass and can thus be recommended as a practical compromise

Metabolic versatility in full-scale wastewater treatment plants performing enhanced biological phosphorus removal

This study analysed the enhanced biological phosphorus removal (EBPR) microbial community and metabolic performance of five full-scale EBPR systems by using fluorescence in situ hybridisation combined with off-line batch tests fed with acetate under anaerobic-aerobic conditions. The phosphorus accumulating organisms (PAOs) in all systems were stable and showed little variability between each plant, while glycogen accumulating organisms (GAOs) were present in two of the plants. The metabolic activity of each sludge showed the frequent involvement of the anaerobic tricarboxylic acid cycle (TCA) in PAO metabolism for the anaerobic generation of reducing equivalents, in addition to the more frequently reported glycolysis pathway. Metabolic variability in the use of the two pathways was also observed, between different systems and in the same system over time. The metabolic dynamics was linked to the availability of glycogen, where a higher utilisation of the glycolysis pathway was observed in the two systems employing side-stream hydrolysis, and the TCA cycle was more active in the A O systems. Full-scale plants that showed higher glycolysis activity also exhibited superior P removal performance, suggesting that promotion of the glycolysis pathway over the TCA cycle could be beneficial towards the optimisation of EBPR systems

Determination of the extraction kinetics for the quantification of polyhydroxyalkanoate monomers in mixed microbial systems

For the first time, a systematic approach was conducted to determine the key factors influencing the kinetics of hydroxyalkanote (HA) extraction in biological systems. Six mixed microbial systems where polyhydroxyalkanoate (PHA) is produced were evaluated. Experiments were carried out for full-scale and lab-scale activated sludge systems using different configurations (containing floccular or granular sludge), as well as specific PHA accumulating cultures that contain high or low intracellular PHA fractions. The overall reaction was limited by the kinetics of the PHA hydrolysis in floccular cultures, whereas in granular cultures, it was limited by the cell lysis step. The monomeric composition of the polymer also had an impact on the HA extraction rate: higher acid concentration and a longer digestion time should be employed when cells accumulate monomers with more substituents, such as hydroxy-2-methylbutyrate (H2MB) and hydroxy-2-methylvalerate (H2MV). This study optimised the method for HA extraction, which impacts the assessment of the quantity and quality of PHA biopolymers

The development of self-awareness and relationship to emotional functioning during early community reintegration after traumatic brain injury

Impaired self-awareness may affect clients' emotional status, engagement in rehabilitation and community reintegration following traumatic brain injury (TBI). The study aimed to investigate the relationship between self-awareness, emotional distress and community integration in adults with TBI during the transition from hospital to the community. Thirty-four rehabilitation clients with TBI were assessed in the week before and 2 months after discharge home. Measures of self-awareness and emotional functioning were administered predischarge and repeated at follow-up along with a measure of community integration. Nonparametric tests were used to compare levels of self-awareness and emotional distress pre- and postdischarge, their interrelationships and association with community integration. Self-awareness significantly increased following discharge, and a trend towards increased depression was found. There were no consistent relationships found between level of self-awareness, emotional functioning, and community integration. The development of self-awareness in the immediate postdischarge phase suggests this is an important time for clinical interventions targeting compensation strategies and adjustment to disability