Comparison between automated anaerobic digestion test systems for determination of biochemical methane potential of cellulose

This study investigated the use of two automated systems, the Automatic Methane Potential Test System II (AMPTS II) and the CJC lab system, a newly developed system, to measure BMP of cellulose

The influence of mixed solvents volatility on charge state distribution of peptides during positive electrospray ionization mass spectrometry

Understanding the mechanisms that control and concentrate the observed electrospray ionisation (ESI) response from peptides is important. Controlling these mechanisms can improve signal-to-noise ratio in the mass spectrum, and enhances the generation of intact ions, and thus, improves the detection of peptides when analysing mixtures. The effects of different mixtures of aqueous: organic solvents (25, 50, 75%; v/v): formic acid solution (at pH 3.26) compositions on the ESI response and chargestate distribution (CSD) during mass spectrometry (MS) were determined in a group of biologically active peptides (molecular wt range 1.3 - 3.3 kDa). The ESI response is dependent on type of organic solvent in the mobile phase mixture and therefore, solvent choice affects optimal ion intensities. As expected, intact peptide ions gave a more intense ESI signal in polar protic solvent mixtures than in the low polarity solvent. However, for four out of the five analysed peptides, neither the ESI response nor the CSD were affected by the volatility of the solvent mixture. Therefore, in solvent mixtures, as the composition changes during the evaporation processes, the pKb of the amino acid composition is a better predictor of multiple charging of the peptides

High performance liquid chromatography coupled to electrospray ionisation mass spectrometry method for the detection of salivary human neutrophil alpha defensins HNP1, HNP2, HNP3 and HNP4

Human neutrophil alpha defensins are antimicrobial peptides involved in the first line of defence against invading pathogens. To develop a deeper understanding of the immune responses in relation to airway inflammation and exercise induced epithelial damage it is necessary to have a sensitive method that can detect these peptides in a saliva matrix. A selective and sensitive Liquid Chromatography Mass Spectrometry (LC-MS) method for the detection of four salivary HNP (HNP1, HNP2, HNP3 and HNP4) peptides has been developed and validated. The LC-MS responses of HNPs 1-3 were compared with the response obtained from the traditionally used enzyme-linked immunosorbent assay (ELISA) that measures the combined levels of these three defensins. The peptides were separated on a Phenomenex Kinetex® C8 column (50 x 3.0 mm, 2.6 µm) on an Agilent 1200 series HPLC system using a linear MeOH: H2O: acetic acid (0.1% v/v) gradient. The HPLC was coupled to a Waters Synapt G1 Electrospray Quadrupole Time of Flight mass spectrometer. A full scan range from 100-2000 m/z in the positive ion mode was used for the acquisition. The LC-MS method was linear for concentrations of HNP2 between 0.05 and 1 ng/µL with a LOD of 0.05 ng/µL and LOQ of 0.1 ng/µL. Inter- and intra- assay precisions (%CV) were 0.3 and 14.95%, respectively. HNPs were extracted from saliva by solid-phase extraction (SPE) with a recovery of 80-91%. The cross-validation data revealed no significance quantitative difference between LC-MS and ELISA (R2= 0.96) and confirms that the developed LC-MS method is a reliable method for the detection of these antimicrobial markers. However, superior selectivity in the developed LC-MS method provides a unique opportunity to assess individual alpha defensin levels in the same assay. HNP1, HNP2, HNP3 and HNP4 were evaluated in young athletes before, and up to, 2.5 h after an exercise intervention in order to assess if the developed LC-MS method was sensitive enough to detect rapid changes in their relative levels

Reflection and learning in clinical nursing education mediated by ePortfolio

This paper reports on an investigation into learning mediated by the elective elements of an electronic portfolio (ePortfolio) designed to facilitate four learning styles. The design takes a phenomenological-hermeneutic approach. The setting was Course 4, a ten-week clinical course in Basic Nursing. The participants were eleven first-year students on Course 4 randomly selected. Data was generated by participant observations, interviews and portfolio documents. The entire material was interpreted according to Ricoeur’s theory of interpretation. The study showed that the elective elements of ePortfolio were mostly used by students with theorist style and used the least by students with pragmatist style. Some students can reflect without a learning tool, other students need supervision. The themes a fellow player and an opponent were deduced. The conclusion was that the elective elements work like fellow players and opponents, as they facilitate reflections on nursing practice and one’s own learning processes, and they mediate learning of important nursing competency elements. The tools can promote differentiation of supervision, and allow more time to supervise students who need more support. There is potential to enable students to select among the learning tools

Sargassum – Menace, Methane, Mouth and More

Despite 72% of the Earth’s surface being covered by oceans the area used for seaweed cultivation is relatively small compared to that of land crops. Although, global utilisation of marine algae has grown to a multibillion dollar industry, primarily for food and hydrocolloids, it is a relatively small part of the current blue economy with a limited number of products available. There is tremendous potential for further exploitation of seaweed for fuel, feed, biochemicals, nutraceuticals and pharmaceuticals. The brown seaweed Sargassum muticum is an invasive species to the coasts of the British Isles, mainland Europe and North America. Attempts at its eradication and control have generally not been successful, although time-consuming and costly. Commercial exploitation of this biomass for food, fuel and pharmaceutical products could encourage its harvesting and control. Sargassum has a naturally high content of antioxidants, carotenoids and phenols, including the well-known anti-cancer compound fucoxanthin, making this species a potential source of a range of pharmaceutically relevant materials. Macroalgae may also be a potential source of fuel. This paper discusses the some of the recent research at the University of Greenwich on Sargassum and potential process hurdles to exploit it for both fuel and high value products, but focuses particular on the on pre-treatment, preservation and conversion of the wet biomass to biogas. Anaerobic digestion (AD) is generally the process of choice for energy production from high water content biomass, and biogas produced from AD is being used to make the most of a number of biomass wastes by turning them into renewable energy. It is a safe and cost-effective way to dispose of unwanted organic waste, and for this reason, a favoured solution for industry and governments. However, practical yields of biogas from the anaerobic digestion of macroalgae are substantially below the theoretical maximum with Sargassum muticum yielding ~25 % of the theoretical maximum. Alginates are a major component of the cell-wall of brown algae, and alginic acid and its sodium salt were found to be recalcitrant with average methane yields of equivalent to only 23% - 28% of their theoretical methane potential. Methane yield was further reduced by the presence of high concentrations (7% of substrate equivalent to 17.5 mg L-1) of the phenolics, phloroglucinol, the basis of phlorotannins, the predominant polyphenol in many seaweeds, and epicatechin. Pre-treatment by washing S. muticum did not affect overall methane production during AD, but significantly slowed down the initial rate of biomethane production. The harvesting of S. muticum is seasonal; thus, there will be a need to preserve and store seaweed to supply a year-round processes such as anaerobic digestion for biogas production. Ensiling is widely used in terrestrial agriculture to preserve fodder. In ensilage, lactic acid fermentation under anaerobic conditions converts water soluble carbohydrates into organic acids, mainly to lactic acid; the pH decreases and the moist crop is preserved. Ensiling was found to be an effective, low energy loss method of preserving seaweed with energy loss from the biomass due to ensiling <8 % of the higher heating value of seaweed feedstock. Ensiling had no significant effect on methane yield from AD. Pre-treatment prior to ensilage can effect leachate losses; size reduction of seaweed prior to ensilage reduced leachate and energy loss from the biomass, but washing with freshwater increased leachate losses from ensiling

The Lower–Middle Jurassic of the Anholt borehole: implications for the geological evolution of the eastern margin of the Danish Basin

This study of Upper Pliensbachian – Bajocian/Bathonian deposits in a borehole drilled on the island of Anholt, Denmark incorporates sedimentology, biostratigraphy (palynomorphs and foraminifera), palaeomagnetism and coal petrology. The studied succession records a gradual change from marine inner shelf storm-influenced clays to mainly terrestrial sands, clays, and lignite containing a flora of mainly freshwater algae and pollen. The regression was initiated at the Pliensbachian–Toarcian boundary and marine influence ceased during Bajocian–Bathonian times; the regression thus took place earlier at Anholt than in the centre of the Danish Basin. The sediments in the Anholt borehole are referred to the Fjerritslev and Haldager Sand Formations. Although the Lower–Middle Jurassic boundary is commonly placed at the boundary between the two formations, our data indicate that at Anholt the upper Fjerritslev Formation (member F-IV) is of Aalenian age. The Lower–Middle Jurassic boundary occurs close to the boundary between members F-III and F-IV of the Fjerritslev Formation. In contrast to other Lower–Middle Jurassic successions in the North Sea region, smectites of inferred volcanic origin are preserved in the Anholt section, suggesting limited burial and hence less intense diagenetic illitisation or chloritisation of smectites. A down-hole increase in diagenetic influence is reflected by the increase down-section both in the thermal stability of kaolinite and in the vitrinite reflectance. Kaolinite of inferred authigenic origin forms a white powder in the quartz-dominated sands of the Haldager Sand Formation; this kaolinite is thermally very unstable and is interpreted to be of late diagenetic, post-uplift origin. The vitrinite reflectance data indicate that the Jurassic formations have been exposed to thermal maturation corresponding to burial to a depth of 1000–1200 m below their present depth. Post-maturation uplift of the order of 1 km probably occurred partly during Late Cretaceous – Paleocene inversion in the Kattegat area and partly during Oligocene–Recent regional uplift, the latter being the most important of the two uplift phases. Palaeomagnetic data indicate that the main carrier of magnetic remanence is fine-grained magnetite. The stable remanence shows a pronounced inclination shallowing, which is attributed to post-depositional compaction