Birthe Vejby Nielsen

Birthe Vejby Nielsen
University of Greenwich · Faculty of Engineering and Science

PhD, MSc

About

45
Publications
18,861
Reads
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626
Citations
Citations since 2017
21 Research Items
566 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150

Publications

Publications (45)
Article
Full-text available
During electrospray ionization mass spectrometry (ESI-MS) analysis of proteins, the addition of supercharging agents allows for adjusting the maximal charge state, affecting the charge state distribution, and increases the number of ions reaching the detector thus, improving signal detection. We postulate that in di-substituted arene isomers, molec...
Article
Full-text available
In electrospray ionization mass spectrometry (ESI-MS), analytes are introduced into the mass spectrometer in typically aqueous-organic solvent mixtures, including pH modifiers. One mechanism for improving the signal intensity and simultaneously increasing the generation of higher charge-state ions is the inclusion of small amounts (approx. <0.5% v/...
Article
Full-text available
Microalgae, a popular source of food and bioactive compounds, accumulate antioxidants in response to culture condition stresses. Using a factorial design (3 × 3), the effect of light, temperature, and nitrogen level on chlorophyll and carotenoids, total protein, total phenolic, ascorbate and glutathione content, and enzyme (catalase (CAT), superoxi...
Chapter
Full-text available
Sargassum muticum is a brown seaweed which is invasive to Europe and currently treated as waste. The use of S. muticum for biofuel production by anaerobic digestion (AD) is limited by low methane (CH 4 ) yields. This study compares the biochemical methane potential (BMP) of S. muticum treated in three different approaches: aqueous methanol (70% MeO...
Conference Paper
Full-text available
Since 2011 beaches across the Caribbean, the Gulf of Mexico, and West Africa, have experienced massive inundations of pelagic Sargassum, known as ‘golden tides’, significantly impacting the local economy and environment. These consist of holopelagic Sargassum fluitans and S. natans and when floating are ecologically important. They are the spawning...
Article
Full-text available
The urgent need to replace fossil fuels has seen macroalgae advancing as a potential feedstock for anaerobic digestion. The natural methane productivity (dry weight per hectare) of seaweeds is greater than in many terrestrial plant systems. As part of their defence systems, seaweeds, unlike terrestrial plants, produce a range of halogenated seconda...
Article
Full-text available
Biogas production from Sargassum muticum, an invasive seaweed species to Europe, is hampered by low methane (CH4) yields during anaerobic digestion (AD), but causes are unclear. This research is the first to demonstrate the impact of extensive freshwater washing of spring- and summer-harvested S. muticum on the CH4 production rates and the biochemi...
Article
Microalgae biomass is considered a sustainable feedstock to produce high-value compounds including enzymatic and non-enzymatic antioxidants, which are widely used for food, pharmaceuticals, textile, leather, and in the chemical industries. Optimal post-harvest storage conditions to minimise deterioration of enzyme activity is therefore crucial. In...
Article
Full-text available
The potential of algal biomass as a source of liquid and gaseous biofuels has been the subject of considerable research over the past few decades, with researchers strongly agreeing that algae have the potential of becoming a viable aquatic energy crop with a higher energy potential compared to that from either terrestrial biomass or municipal soli...
Article
Full-text available
Practical yields of biogas from the anaerobic digestion of macroalgae and, Sargassum muticum in particular, are substantially below the theoretical maximum. There is considerable conjecture about the reasons for the relatively low practical methane yields from seaweed, and polyphenols are suggested as one of the elements in the low yield of methane...
Article
Full-text available
Macroalgae represent a potential biomass source for the production of bioethanol or biogas. Their use, however, is limited by several factors including, but not restricted to, their continuous supply for processing, and low biofuel yields. This review examines recent pre-treatment processes that have been used to improve the yields of either biogas...
Article
Objective: This study examines the long-term effects of ingesting hydrolyzed beef protein versus carbohydrate on indirect markers of immunity during 10-week of endurance training in master-aged triathletes (n=16, age 35–60 years old). Methods: Participants were randomly assigned to either hydrolyzed beef protein (PRO, n=8) or non-protein isoenerge...
Article
Full-text available
Appropriate nutritional supplementation is crucial for athletic performance, particularly for female endurance athletes as their numbers steadily increase. This report involves a set of six case studies examining the effects of ingesting a post-workout supplement containing beef, or whey or carbohydrate on iron status, blood indices, muscular thick...
Article
Full-text available
The pretreatment of seaweed by washing in freshwater is often used in seaweed biofuel research studies. However, the effect of washing seaweed prior to anaerobic digestion (AD) does not appear to have been greatly studied. This study examines washing Sargassum muticum with freshwater and its effect on ultimate and proximate analyses, salt content,...
Article
Full-text available
The search for potent and selective therapeutic agents is progressing by the study of natural compounds in plants. Plant-derived macromolecules are considered emerging therapeutic agents and an alternative to synthetic and small molecule drugs. Where it has long been known that plants possess medicinal properties, the compounds responsible for thei...
Article
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...
Article
Objective: The present study compares the effect of ingesting hydrolyzed beef protein, whey protein, and carbohydrate on performance, body composition (via plethysmography), muscular thickness, and blood indices of health, including ferritin concentrations, following a 10-week intervention program. Methods: After being randomly assigned to one o...
Article
Full-text available
PurposeTo examine the impact of ingesting hydrolyzed beef protein, whey protein, and carbohydrate on resistance training outcomes, body composition, muscle thickness, blood indices of health and salivary human neutrophil peptides (HNP1-3), as reference of humoral immunity followed an 8-week resistance training program in college athletes. Methods T...
Article
Full-text available
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 o...
Article
We describe the qualitative and quantitative analysis of the complexation properties towards cations of a cyclic peptoid hexamer composed of alternating α-and β-peptoid monomers, which bear exclusively chiral (S)-phenylethyl side chains (spe) that have no noticeable chelating properties. The binding of a series of monovalent and divalent cations wa...
Poster
Full-text available
Beef is anutrient-rich, high quality protein source containing all the essential amino acids in proportions similar to those found in human skeletal muscle. The current study examined the impact of ingesting hydrolysate beef protein, whey protein and carbohydrate on salivary alpha-defensins (HNP1) 3), body composition, jump performance and blood ma...
Article
Full-text available
Marine seaweeds represent an abundant source of natural products and may harbour valuable chemicals. 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 Commerci...
Conference Paper
Full-text available
Crude glycerol appears to be a suitable substrate for the production of biogas. The use of crude glycerol to produce biogas could be an alternative to costly refining to produce a fuels for compression ignition engines. However, as with other seaweeds, S. muticum appears to be particularly resistant to anaerobic fermentation. There is considerable...
Poster
Full-text available
This study investigates the effects of physical stress (exercise) in mucosal secretion that contribute to innate immunity are virtually unexplored. This is the first study that has investigated the correlation between stress hormones (cortisol) and growth hormone (testosterone) against potential antimicrobial peptide (α- Defensins).
Poster
Full-text available
To date, no studies have systematically investigated the effect of acute (min to hours) and chronic (days to weeks) change in salivary αdefensins family before and after crossfit exercise by LC-ESI-MS. This work demonstrates that HNP 1-4 could be used as potential stress biomarkers and this assay is potentially more specific than ELISA assays, thus...
Poster
Full-text available
Antimicrobial peptides (α- Defensins) are commonly measured by ELISA, however, this technique does not discriminate between HNP1-3 due to their structural similarities (Figure-1). With advances in mass spectrometry techniques, Liquid Chromatography Mass Spectrometry LC-ESIMS is often considered as a first choice for analysis of salivary peptides. T...
Article
Full-text available
Homocysteine (Hcys) is a non-essential amino acid associated with a range of diseased and abnormal metabolic conditions. Hcys concentration in saliva is routinely determined by enzyme assays, which are broadly specific, but can be expensive and suffer from cross-reactivity. Total Hcys (tHcys) concentrations in eight healthy adults were determined t...
Article
Full-text available
Abstract The aim of this study was to examine the acute response to plasma and salivary cortisol and testosterone to three training protocols. Ten trained endurance athletes participated in three experimental trials, such as interval training (INT), tempo run (TEMP) and bodyweight-only circuit training (CIR), on separate days. Blood and saliva samp...
Article
Full-text available
To aid in the detection of trace quantities of neuropeptides in a biological matrix (as saliva), the influence of different electrolytes and a supercharging reagent on the positive electrospray ionisation mass spectrometry (ESI-MS) response was investigated. Ammonium acetate, sodium chloride and sodium bicarbonate (10(-7) M to 10(-3) M) and the sup...
Conference Paper
Full-text available
Introduction Cortisol (C) and testosterone (T) are important biomarkers of acute and chronic stress (Urhausen et al., 1995). However, it is unclear how different forms of training affect the response of these hormones. Additionally mass spectrometry (MS) is currently widely used in pharmaceutical and health industries to measure small biomarkers; h...
Article
Electrospray ionisation (ESI) is a selective process and, for similar sized analytes, the intrinsic properties of the molecules affect the ionisation process and their response. This research sets out to determine the effect of some of these properties in peptides: peptide polarity and the presence of arginine at positions 1 and 4 in the amino acid...
Article
Full-text available
Background: Cortisol and testosterone are important biomarkers of both acute and chronic stress and decreased testosterone/cortisol ratio has been implicated as a marker of overtraining (Urhausen and Kindermann, 2002: Sports Medicine, 32 (2), 95-102). Commonly used hormone measurement tools such as enzyme-linked immunoassays (ELISA) techniques are...
Article
Full-text available
An in vitro method for the time-resolved quantification of acid-mediated tooth demineralisation has been developed and evaluated against putative non-permanent protective formulations based on a series of poly(alkyl methacrylate)s. Using a thermostatted carousel, dentally relevant substrates consisting of hydroxyapatite discs or sections of bovine...
Article
Cortisol (C) and testosterone (T) are important biomarkers of acute and chronic stress (Urhausen et al. Sports Med 1995;20:251-76). However, it is unclear how different forms of training affect the response of these hormones. The purpose of this study was to examine the effect of various training sessions on salivary C and T in competitive male run...
Article
Indolin-2-one (oxindole), (I), undergoes a Knoevenagel condensation with ferrocene-1,1'-dicarbaldehyde, (II), to afford the title complex 3,3'-[(E,E)-ferrocene-1,1'-diyldimethylidyne]diindolin-2-one dichloromethane disolvate, [Fe(C(28)H(20)N(2)O(2))]·2CH(2)Cl(2), (IV). The structure of (IV) contains two ferrocene complex molecules in the asymmetric...
Article
Full-text available
We investigated the pre-electrospray ionisation (pre-ESI) factors; analyte concentration (1-2500  ng/mL), concentration of formic acid (FA) in the mobile phase (0.01, 0.1 and 1%), concentration of the organic modifier (acetonitrile 50-90%) and flow rate (<10  μL/min) on the number of multiple protonations and ESI response for two neuropeptides (of...
Article
Full-text available
We investigated the pre‐electrospray ionisation (pre‐ESI) factors; analyte concentration (1–2500 ng/mL), concentration of formic acid (FA) in the mobile phase (0.01, 0.1 and 1%), concentration of the organic modifier (acetonitrile 50–90%) and flow rate (<10 μL/min) on the number of multiple protonations and ESI response for two neuropeptides (of ~3...
Article
Full-text available
Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and su...
Article
Full-text available
Electrospray ionisation (ESI) is a selective process and, for similar sized analytes, the intrinsic properties of the molecules affect the ionisation process and their response. This research sets out to determine the effect of some of these properties in peptides: peptide polarity and the presence of arginine at positions 1 and 4 in the amino acid...
Article
Full-text available
Cited References Count:20|SPRINGER|VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS|ISI Document Delivery No.:648PD
Article
The high-mobility group (HMG) proteins of the HMGB family are chromatin-associated proteins that act as architectural factors in various nucleoprotein structures, which regulate DNA-dependent processes such as transcription and recombination. Database analyses revealed that in addition to the previously identified HMGB1-HMGB5 proteins, the Arabidop...

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Projects

Projects (3)
Project
Using microalgae as a source of industrial antioxidant enzyme
Project
Trial Registration: ClinicalTrials.gov, U.S. National Institutes of Health. Identifier: NCT02425020 in resistance trained athletes ClinicalTrials.gov ID: NCT02675348 in endurance trained athletes