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Which fatigue scale should I use? A Rasch analysis of two fatigue scales in inflammatory conditions
Get PDFOBJECTIVES: This study aimed to assess the psychometric properties of two widely used fatigue scales in a sample of patients with inflammatory conditions.
METHODS: Rasch analysis was used to examine scale reliability, item bias, unidimensionality and overall fit to the Rasch model. Sub-test methodology was utilised to attempt to improve model fit for the CFQ and BRAF-MDQ.
RESULTS: Initial analysis displayed strong reliability (PSI=0.89 0.96), alongside a lack of item bias in both scales. However, evidence for unidimensionality was not found for either scale. Overall fit to the Rasch model was marginal for the CFQ, and misfitting for the BRAF-MDQ. Local dependency was observed, as well as significant item misfit for both scales. Sub-test modifications resulted in the best model fit for the BRAF-MDQ (χ2(16)=15.77, p=0.469) and the CFQ (χ2(25)=15.49, p=0.929). Modifications resulted in improved fit, reductions in measurement error, and the production of ordinal-to-interval conversion tables for both scales. Conversion tables apply the benefits of enhanced measurement accuracy, valid comparison of BRAF-MDQ and CFQ scores to other interval-level data, appropriate use in parametric statistics, and enhanced precision in clinical cut-off scores-without the need to change administration format.
CONCLUSION: The BRAF-MDQ and CFQ are valid, reliable tools for fatigue assessment. Psychometric indices and content factors suggest the CFQ is suited to measuring general fatigue, particularly when response burden is a concern, while the BRAF-MDQ should be used in clinical presentations where other symptoms are severe and the impact of fatigue on daily living, emotional, and social well-being is of interest
Fermentation of vitamin K2 (menaquinone-7): Development of an optimal fermentation process to selectively enhance the production of the biologically significant all-trans isomer
No full textVitamin K is a lipid-soluble vitamin first discovered in 1929 by the Danish nutritional biochemist Carl Peter Henrick Dam as an antihaemorrhagic factor capable of correcting dietary-induced bleeding disorders in chicks. The vitamin K family encompasses a series of structurally related compounds, namely vitamin K1 (phylloquinone), vitamin K2 (menaquinones), and vitamin K3 (menadione), which share a common 2-methyl-1,4-naphthoquinone moiety but differ in the structure of a lateral isoprenoid chain at the 3-position. Despite their structural similarities, all K vitamers have different pharmacokinetic properties attributable to the length and degree of saturation of their isoprenoid side chain.
All vitamin K isoforms are involved in the activation of hepatic and extrahepatic vitamin K-dependent proteins (VKDPs) and play a central role in blood coagulation and haemostasis. Additionally, it has been established that the potential health benefits of vitamin K are far more diverse. In particular, menaquinones (MKs) offer more significant health gains than phylloquinone (PK) and have been associated with the prevention of osteoporosis and cardiovascular diseases (CVDs) and decreasing the risk of and improving the outcomes associated with several illnesses and health conditions, including cancer, neurological diseases, type 2 diabetes mellitus, chronic kidney disease, immune disorders, obesity, and coronavirus disease 2019 (COVID-19).
Of the various MKs, menaquinone-7 (MK-7) has superior bioavailability due to its long plasma half-life. Thus, it is considered the most notable form of vitamin K2 and has the greatest efficacy with respect to extrahepatic biological functions. However, MK-7 exists at low concentrations in limited foods, especially those with universal appeal. This has incentivised the development of MK-7 dietary supplements and functional food products to complement natural sources and satisfy the daily intake requirements of this essential vitamin.
Recently, it has been recognised that MK-7 exists as geometric isomers, comprising the bioactive all-trans isomer and various cis forms of the compound, which lack or have considerably compromised biological significance. This is a salient aspect worthy of attention, as the effectiveness of MK-7 nutritional supplements is primarily determined by the content of all-trans MK-7, and all other isomers of the vitamin are essentially impurities that lack therapeutic value.
MK-7 can be produced synthetically from chemical reaction methods or naturally from bacterial fermentation. The latest market trend promoting natural and organic alternatives over synthetic products has rendered natural fermentation-based synthesis more favourable from a consumer’s perspective. Furthermore, microbial production is a more sustainable approach for the large-scale synthesis of MK-7; hence, natural fermentation techniques can satisfy both the market demand and sustainable development goals.
The MK-7 isomer composition of the final product is influenced by many factors, predominantly the methods used for its production and the purification of the post-reaction mixture, as well as exposure to certain environmental factors and storage conditions. It is important to appreciate that while studies analysing the isomer profile of MK-7 dietary supplement preparations of various origins have been carried out, the isomer composition resulting from fermentation processes has not been elucidated.
In light of the fact that only all-trans MK-7 sustains biological activity and fermentation-based synthesis is superior from both the viewpoint of consumers and the environment, the MK-7 isomer profile attained from fermentation warrants further investigation. Therefore, the fundamental aim of this research was to evaluate the MK-7 isomer composition resulting from fermentation processes employing different synthesis conditions to explicate the optimal fermentation method for the production of the biologically significant all-trans form of the vitamin. A holistic approach was adopted to systematically follow a typical fermentation process from its foundational stages to the final fermented product while considering the MK-7 isomer profile obtained from fermentation under various conditions and the bioactivity and therapeutic value of fermented MK-7 consumer end products. Accordingly, key aspects of upstream and downstream fermentation were explored, along with nanobiotechnological approaches, to potentially address the major challenges accompanying the fermentation and downstream processing of MK-7. The isomer composition and stability of all-trans MK-7 resulting from exposure to possible conditions and environmental factors encountered during the manufacture, transportation, and storage of fermented bioactive MK-7 goods available on the market were also assessed.
The selection of nutrients, particularly carbon, nitrogen, and salt sources, and their respective concentrations in the fermentation media are a central aspect of any fermentation process, as they influence microbial growth and metabolism and, ultimately, the process productivity and product yield. Thus, the first step was to consider the impact of the media composition on MK-7 isomer production and ascertain the optimum media combination to favour the synthesis of all-trans MK-7. Several nutrient sources were screened, and the concentration of the effective media components was optimised to obtain the ideal fermentation media, which contained 1% (w/v) glucose, 2% (w/v) yeast extract, 2% (w/v) soy peptone, 2% (w/v) tryptone, and 0.1% (w/v) calcium chloride (CaCl2). The optimal fermentation media resulted in an all-trans isomer concentration of 36.37 mg/L and a cis isomer concentration of 1.23 mg/L. It was also established that only a single cis isomer is obtained from fermentation under the investigated conditions. Moreover, different concentrations of the cis isomer were achieved when the selection and concentration of nutrients constituting the fermentation media were varied, implying that the media composition is instrumental in determining the nature of the extracellular environment in the fermentation broth, and this likely influences the extent to which all-trans MK-7 isomerises to the cis form.
Various fermentation parameters and operating conditions also play an indispensable part in fermentation processes, as they contribute to the microbial growth environment and, hence, impact product formation and the efficacy of the fermentation system. Consequently, the subsequent focus was to explore the effect of crucial fermentation parameters, specifically the inoculum size, fermentation temperature, agitation speed, and length of fermentation, on the MK-7 isomer profile. These factors were optimised to enhance the synthesis of the biologically important all-trans isomer and minimise the concentration of cis MK-7 while using the previously developed fermentation media. The optimum fermentation conditions consisted of an inoculum size of 2% (v/v), a fermentation temperature of 40 °C, an agitation speed of 200 rpm, and a fermentation period of 7 days and enabled an all-trans and cis isomer concentration of 53.29 mg/L and 1.22 mg/L, respectively. An approximately 46.5% greater all-trans MK-7 concentration was attained from fermentation utilising the optimal media, inoculum size, temperature, agitation speed, and duration compared to fermentation with only the optimum media composition, which emphasises the pivotal role of the fermentation environment in regulating the production of the desired isomer.
Although fermentation is the preferred method for MK-7 synthesis, its low yield and large number of downstream processing steps increase production expenses and the cost of the final product. The high price of fermented MK-7 supplements reduces their widespread accessibility. While optimisation of various aspects of the fermentation process, such as the fermentation format, nutrient selection and media composition, and value of key fermentation parameters and operating conditions, serves to enhance the production and yield of MK-7, it offers little opportunity to refine the fermentation system through process intensification. Therefore, there is a need for innovative approaches to not only boost the process yield but also streamline the overall fermentation procedure by decreasing the complexity and number of unit operations involved in the downstream processing of the vitamin. It is also essential to ensure that all-trans MK-7 is produced almost exclusively or in the most significant proportion during fermentation. In this regard, bacterial cell immobilisation with biocompatible magnetic iron oxide nanoparticles (IONs) was investigated to assess their influence on the MK-7 isomer profile obtained from fermentation. Three types of IONs, including one uncoated (naked) and two coated (amine-functionalised) IONs, were synthesised using the co-precipitation method and characterised using several techniques, and their effect on microbial growth and the production and yield of MK-7 isomers was considered. Naked IONs were initially examined, and the results were compared with the findings for the 3-aminopropyltriethoxysilane (APTES)- and L-lysine (L-Lys)-coated IONs (IONs@APTES and L-Lys@IONs). The optimum concentration of naked IONs was 300 μg/mL, and it improved the process output and resulted in an all-trans MK-7 concentration of 28.78 mg/L and a 1.6-fold greater all-trans isomer yield relative to the control. In comparison to the naked IONs, the amine-functionalised IONs had superior properties and provided more positive outcomes. The optimal IONs@APTES and L-Lys@IONs concentrations were 300 μg/mL and 400 μg/mL, enabling a maximum all-trans MK-7 concentration of 41.93 mg/L and 32.08 mg/L, respectively. In addition, the yield of the biologically effective isomer compared to the control increased by 3.1-fold for the IONs@APTES and 2.1-fold for the L-Lys@IONs. Of all three forms of IONs that were explored, it was determined that 300 μg/mL of IONs@APTES was the most beneficial to enhance the all-trans isomer concentration and minimise the synthesis of cis MK-7. The magnetic nature of IONs also increases the scope for process intensification through magnetic separation technology, which has the potential to improve the productivity of MK-7 fermentation.
It is of interest to note that the greatest all-trans MK-7 concentration obtained in the presence of IONs (41.93 mg/L) was less than that achieved in their absence when applying the same fermentation media and operating conditions as previous experiments (53.29 mg/L). This disparity can be attributed to the different fermentation volumes used in the two studies, as even the untreated (control) samples in the experiments involving IONs resulted in considerably lower concentrations of the all-trans isomer (less than 15 mg/L). All prior investigations were carried out on a small scale (6 mL), whereas the studies employing IONs required a slightly greater volume (approximately 20 mL) to accommodate the inclusion of IONs in the fermentation medium and the related measurements. It is apparent that even a small increase in the volume and, consequently, the scale of the fermentation process has a noticeable impact on the concentration of the target product. These observations highlight the central role of the fermentation volume in determining the concentration of all-trans MK-7 attained on a larger scale and present basic knowledge of likely challenges associated with the scale-up of fermentation processes targeting the production of the bioactive isomer.
It has been proposed that exposure to various environmental conditions influences the isomer composition of MK-7 products. Awareness of these factors and their impact on the proportion of MK-7 isomers is vital to preserve the content of the biologically significant all-trans isomer and prevent its transformation to cis MK-7 during the storage of fermented MK-7 supplements and fortified or functional foods. In this respect, the effect of short-term exposure to common environmental factors and storage conditions, such as light, atmospheric oxygen, and different temperatures, on the MK-7 isomer profile was considered to establish the optimum conditions to conserve the quantity of the all-trans isomer during the storage of fermented MK-7 preparations. It was ascertained that the vitamin is reasonably heat-stable but extremely light-sensitive. Long-term storage at a low temperature with minimal oxygen exposure in the absence of light resulted in a negligible change in the concentration of the all-trans isomer and was, thus, the optimal environment for the prolonged storage of fermented all-trans MK-7. These findings provide a deeper understanding of the impact of different environments on the stability of the biologically efficacious isomer and are a valuable step forward in establishing ideal storage conditions to maintain the concentration of all-trans MK-7 in fermented nutritional supplements.
Overall, this research presents novel insights into the MK-7 isomer profile achieved from fermentation in various contexts, a previously unexplored field, and has laid the foundation for future studies. Although it is desirable to exclusively produce the bioactive isomer from fermentation, the collective experimental findings have revealed that obtaining small quantities of the cis isomer alongside all-trans MK-7 is largely unavoidable under the circumstances considered. However, it is possible to maximise the concentration of the all-trans isomer and minimise the amount of the biologically insignificant isomer, which is a reasonable compromise. Appreciation of the key factors that influence the MK-7 isomer composition resulting from fermentation will allow their manipulation to attain a more favourable MK-7 profile in the final preparation, which can be included in nutraceuticals, dietary supplements, and functional food products or used in purified form. Furthermore, the outcomes of this study have the potential to aid the development of an industrial fermentation process that specifically targets the production of the biologically active and therapeutically valuable all-trans MK-7 isomer. The prospect for process intensification through the innovative use of magnetic IONs will likely streamline the production system and decrease the related expenses. This will help reduce the price and increase the accessibility of fermented bioactive MK-7 supplements and fortified or functional foods. Moreover, a greater understanding of the environmental factors and storage conditions that affect the isomer composition of fermented MK-7 preparations is likely to improve the standard of MK-7 nutritional products by preserving the quantity of the all-trans isomer. The widespread availability and consumption of high-quality bioactive MK-7 products by a range of consumers are expected to raise the vitamin K status of individuals and decrease the risk and progression of several age-related disorders and diseases of global significance. This holds great promise for reducing the disease burden and alleviating the socioeconomic consequences of an ageing population
The Mātauranga Māori in Mathematics Directive: Exploring the place of mātauranga Māori in Mathematics teaching and learning
Get PDFThis thesis explores issues concerning mātauranga Māori in mathematics teaching and learning here in Aotearoa. The Ministry of Education has directed that mana ōrite mō te mātauranga Māori be embedded in teaching, learning, and assessment. Thus, this research primarily aims to understand the development leading to the directive of including mātauranga Māori in education policies. For the English-medium secondary education settings, the second and third aims of this research are to explore what mātauranga Māori means to teachers of mathematics and to consider the connections between mātauranga Māori and mathematics teaching and learning. To investigate these aims, a semi-structured group discussion with four secondary mathematics teachers from an English-medium setting was conducted. The results of this thesis highlight the confusion and challenges secondary mathematics educators have toward defining, and subsequently, implementing mātauranga Māori in their classrooms. This thesis also found that there is enthusiasm and interest around learning how to ensure indigenous and marginalised learners reach their mathematics potential. Believing that indigenous worldviews have the potential to shift education outcomes for minority learners, this thesis adds to literature related to indigenous education, secondary mathematics education, and English-medium education of Māori learners
Forest change mapping using remote sensing and Google Earth Engine
Get PDFWith advancements in data sources, software, and image analysis techniques, remote sensing has become an efficient method for forest classification. However, access to this technology has been limited for developing countries due to the high cost of high resolution images and analysis software. A potential solution is that NASA and the European Space Agency provide free access to mid-low resolution satellite images. In addition, Google Earth Engine (GEE), a free cloud-based geospatial analysis platform, has allowed researchers from developing countries to conduct research without relying on costly remote sensing software. This study evaluates the suitability of the freely available images and the GEE platform for different forest management applications in Sri Lanka. The research focused on three different scenarios in vegetation mapping: identifying home gardens, monitoring invasive pines, and forest cover mapping in a tropical montane region.
Home garden is an agroforestry class seen in tropical countries often overshadowed by global land cover classifications. This study used a random forest classification algorithm to classify the home garden, utilizing terrain data and Sentinel-2A images as the dataset. The results confirmed that the red band of Sentinel-2 and textural metrics derived from grey-level co-occurrence matrix analysis are effective in identifying home gardens from other forestry classes.
Monitoring the spread of invasive pines is important for forest management in Sri Lanka. This study used Landsat satellite images for the years 2000 and 2021 to detect the exotic Pinus caribaea species invasion of native habitats. By using an image difference technique, this research identified that the extent of these invasive pines had an overall decline over the past 21 years. Further, results showed that broadleaved forests and grasslands located within 100m of the pine plantations’ borders were susceptible to invasion.
In tropical regions, analysing forests can be difficult due to cloud cover. This research also focused on methods to enhance classification accuracy using multiple data sources: Sentinel-1, Sentinel-2, PALSAR-2, and elevation. Six different methods were tested. It was found that combining radar data with optical and topographical data improved vegetation classification accuracy. In addition, feature importance analysis using the random forest algorithm indicated that radar data plays a significant role in tropical land use classification.
The three case studies used in this research demonstrate that GEE and the freely available mid-low resolution satellite images make the application of remote sensing in Sri Lanka a viable solution for the monitoring and mapping of landcover
Examining the validity of the Mini-Mental State Examination (MMSE) and its domains using network analysis
Get PDFBackground: The Mini-Mental State Examination (MMSE) is the most widely used standardised screener for impairments across a range of cognitive domains. However, the degree to which its domains (orientation, registration, attention, recall, language, and visuospatial) capture cognitive functioning measured using standardised neuropsychological tests is unclear. Method: A longitudinal research design with four biannual assessments over a 6-year period was used with an initial sample of 1037 older adults (aged above 70 years). Participants completed MMSE and neuropsychological tests at each assessment. Network analysis was utilised to investigate unique associations among the MMSE and its domains and neuropsychological test performance at each time point. Results: The total MMSE and two of its domains, language and recall, were associated with neuropsychological memory performance. The MMSE orientation, registration and visuospatial domains did not have any unique associations with neuropsychological performance. No stable internal interconnections between MMSE domains were found over time. The association of total MMSE as well as its recall domain with neuropsychological memory performance remained very similar over the 6-year period. Conclusions: The present study adds evidence to the validity of the MMSE and supports the clinical usage of the MMSE, whereby the total score is used for screening patients with or without cognitive impairments, with repeated administration to monitor cognitive changes over time, to inform intervention. However, the tool is not able to diagnose the cases for changes in specific cognitive domains and as such, should not replace a complete neuropsychological assessment
Breasts are not just battlefields: Breast cancer and metaphors
Get PDFWe analyse how breast cancer patients use metaphor with respect to their illness. The medical humanities (Whitehead and Woods, 2016) already has a rich tradition of coming to appreciate how cancer is discussed by clinicians, patients, survivors, and others. Our research hopes to extend this ongoing discussion by looking within and across two languages: English and Urdu. This research is part of a larger project (a PhD thesis) and in this presentation, we introduce preliminary corpus data and some initial findings from it. We take a corpus linguistics approach to examine how frequent metaphors are used, and we subject them to analysis through the lens of conceptual metaphor theory (Lakoff and Johnson, 1980; Lakoff, 2006). Our corpus is collected from two different languages: Urdu (as spoken in Pakistan) and English (as spoken in New Zealand). It consists of social media language: four YouTube videos (two from each country), transcribed and translated (for Urdu). Our initial findings suggest that, as argued in previous research (Guité-Verret and Vachon, 2021), breast cancer is often framed with reference to war metaphors. However, we also reveal a number of previously undocumented metaphors, for example part-whole relationships, such as ‘if spread from breast then it has the whole body’, which refer to generic level metaphor-miscellaneous metaphors (GenM-MM) Lakoff (2006)
Eliciting informative priors by modeling expert decision making
Get PDFThere are significant limitations to current methods for eliciting the prior beliefs of experts. To combat some of these limitations, this paper proposes an alternative approach that infers an expert’s prior beliefs about an uncertain event, A, from the expert’s past decisions. We show that an analyst can use past information on an expert’s decision-making task, contingent on an expert’s prior of A, to model the decision-making process and infer an approximation of the prior for A. This concept is illustrated by an application to recidivism. We conclude this work by highlighting important directions for future research. Funding: J. R. Falconer’s research is funded through the University of Waikato Doctoral Scholarship
Local editing in Lempel-Ziv compressed data
Get PDFThis thesis explores the problem of editing data while compressed by a variant of Lempel-Ziv compression. We show that the random-access properties of the LZ-End compression allow random edits, and present the first algorithm to achieve this. The thesis goes on to adapt the LZ-End parsing so that the random access properties become local access, which has tighter memory bounds. Furthermore, the new parsing allows a much improved algorithm to edit the compressed data
Fabrication of blended chitosan nanofibers by the free surface wire electrospinning
Get PDFNanofibers are fibers with diameters in the nanometer range. They are characterized by their high surface area to volume ratio, flexible surface functionalities, and superior mechanical properties. Chitosan is a polycationic polymer which is abundant in nature. Chitosan nanofibers have been widely explored for different potential applications such as wound dressing, tissue engineering, and drug delivery systems. It is difficult to directly spin pure chitosan, due to its high molecular weight, low solubility, and high viscosity. To produce nanofibers, chitosan is commonly blended with other polymers that possess fiber forming capabilities such as polyvinyl alcohol, polycaprolactone, and Polylactic acid. In this study chitosan oligomers of an average molecular weight 15 kDa was blended with the three copolymers at different weight ratios. The fibers were prepared by the free surface wire electrospinning process, and the formed Chitosan nanofibers were characterized by Scanning Electron Microscopy (SEM). SEM results showed that blending chitosan with PLA enhances its spinnability and facilitates uniform and smooth morphology. Blending chitosan with PLA produced nanofibers with better quality, compared to PVA, and PCL
Exhausted men: Making fatigue visible in The Metamorphosis and At Swim-Two-Birds
Get PDFThough not always immediately recognizable, fatigue and tiredness play a central role in modernist literature. As society placed increasing value on productive, strong, energetic bodies, the growing presence of bodies tired from the effects of overwork, rapid social progress, illness and post-war malaise posed a threat both to society and ideas of the
able-bodied self. Recumbent bodies challenge expectations of productivity; they remindus of our own bodily fallibility and blur the line between life and death as a visual
representation of our own mortality. Further, the fatigued body at rest is predominantly associated with the feminine, as has been reflected in much prior academic engagement
with neurasthenic women in modernist literature. What then are the implications for fatigued men? This thesis traces the previously overlooked depictions and uses of fatigue in two texts that have been the subject of significant analysis: The Metamorphosis by Franz Kafka and At Swim-Two-Birds by Flann O’Brien. Though neither of these texts are inherently medical in nature, I show how fatigue nonetheless plays a central role in each, albeit in quite different ways. By unpacking these contrasting engagements with fatigue and the simultaneous lack of critical interest in fatigue in these texts, I uncover stigmatizing social perceptions of fatigue as deviant, burdensome, and indicative of emasculating weakness. Further, such depictions seem to go unquestioned, suggesting that these beliefs are largely naturalized within Western society. In the current time of pandemic, as society is again increasingly confronted with very visible exhaustion in the form of Long Covid amongst other fatiguing conditions, modernist fiction from the early-twentieth century offers valuable insights into how we engage with fatigue