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Permian arc volcanism and aspects of the general geology of the Skippers Range, NW Otago
No full textThe Skippers Range in NW Otago is a structurally isolated block bounded by the Alpine Fault to the northwest, the Glade-Darran Fault to the west and the Hollyford Fault to the east. Within it are five intrusive and fault bounded units: The Mantle Volcanics Formation, Twin Lakes Trondhjemite, Skippers Formation, Slip Hill Intrusives and Mount
Webb Gneiss. A small probably fault bounded conglomerate unit of unknown age occurs along the southwestern boundary of the Twin Lakes Trondhjemite.
The Mantle Volcanics Formation is an undeformed, moderately southwest dipping > 1300 m sequence of Early Permian pyroclastic and epiclastic volcanogenic marine sediments extensively intruded by cogenetic basaltic dikes and sills. The sediments are predominantly coarse breccias and crystal lithic tuffaceous sandstones deposited by debris- flows and high-density turbidites on the flanks of an active and at least partially emergent volcanic edifice. A diverse fossil fauna from a new locality has been collected and includes the first reported occurrence of Eurydesmidae in New Zealand. The intrusive rocks span a continuous range from high MgO to high Al2O3 tholeiitic basalts, are characteristically clinopyroxene phyric often with crystals of quite large size and many can be classed as ankaramites. The intrusive suite is shown to be derived from high MgO, Cr and Ni primary parental melts which are represented in the dikes. These melts were emplaced into high crustal levels and erupted often with high crystal contents but without having undergone significant fractionation. The rocks of the Mantle Volcanics Formation have an incipiently developed greenschist facies mineral assemblage but have not fully equilibrated to these conditions. The Mantle Volcanics Formation represents a portion of the Brook Street Terrane, a north trending discontinuous belt of lower Permian island-arc derived volcanics and volcaniclastic sediments offset by the Alpine Fault, and a discussion of this entity is included.
To the west of and separated from the Mantle Volcanics Formation by the Wilmot Fault and the Twin Lakes Trondhjemite pluton is the Skippers Formation with a structural thickness of approximately 2 km. This is composed of essentially three protolithic types: layered ultramafics, a crustal level basic dike/sill complex and highly deformed basaltic tuffaceous sediments. Taken together, these units represent scraps of dismembered island-arc basement possibly formed in a fore-arc setting. The whole of the Skippers Formation is characterised by well equilibrated greenschist facies and actinolite (after ?clinopyroxene) blastoporphyritic textures similar to clinopyroxene porphyritic textures in the Mantle Volcanics Formation are common in all three protoliths.
Three tabular granitoid plutons, the Twin Lakes Trondhjemite between the Mantle Volcanics and Skippers Formations and two coterminous dioritic bodies, Slip Hill Diorite and Slip Hill Granodiorite, between the Skippers Formation and schists and gneisses of the Mount Webb Gneiss are exposed in the Range. The contacts of the Twin Lakes Trondhjemite are presently faulted but there is evidence of it being intrusive into the Mantle Volcanics Formation and Skippers Formation placing a relative age constraint on their juxtaposition. The Slip Hill Intrusives are fault bounded to the east with the Skippers Formation and the Slip Hill Diorite is shown to be intrusive into the earlier deformed Mount Webb Gneiss. The Slip Hill Diorite is very similar to the Mistake Diorite, which intrudes Brook Street Terrane rocks in the Eglinton Valley, in terms of age (Early Triassic) and petrography.
The Mount Webb Gneiss was previously mapped and correlated with the Thurso Formation occurring along the coast of northern Fiordland. Some questions are raised as to the viability of this correlation
Strategies to enhance CAR T cell function in solid tumours utilising coding and non-coding genes
No full textCancer immunotherapy has emerged as an effective treatment to provide benefits to cancer patients. One of the main treatment modalities of cancer immunotherapy is the adoptive transfer of T cells with genetically engineered receptors known as chimeric antigen receptor (CAR), which has recently emerged as a promising approach for haematological cancers. Although some success has been achieved in treating leukaemia, treatment of solid tumours by this approach is limited mainly due to poor infiltration of cancer targeting lymphocytes and their inhibition by immunosuppressive tumour microenvironment (TME) created by hypoxia, low pH, and immunosuppressive metabolites within solid tumours.
In this thesis, we attempted to exploit immunosuppressive metabolites (e.g. adenosine and low pH) in solid TME to reduce their suppressive effect on T cells by designing chimeric receptors with CXCR3 signalling domain fused to the extracellular metabolite sensing receptor. Functionality of these chimeric receptors were assessed using calcium flux assay, ERK phosphorylation assay and migration assays. While the assays were effective at assessing signal transduction via non-modified CXCR3 in response to the cognate ligand, CXCL11, signalling via chimeric receptors was not detected in the presence of respective stimuli.
Immunosuppressive molecules in TME also activate protein kinase A (PKA) in T cells which results in the localization of the PKA regulatory subunit 1A (PRKAR1A) to the immune synapse inhibiting several central proteins involved in the T-cell signalling cascade and leading to T cell inactivation. While research have targeted PRKAR1A using peptides to supress its activity, we used a different approach by overexpressing microRNAs (miRNAs) to downregulate PRKAR1A expression. Overexpression of either miR96/183 or miR155 significantly downregulated PRKAR1A expression in HEK293 cells at both mRNA and protein level. We further validated PRKAR1A 3' UTR as a direct target of both miRNAs using luciferase assay. Additionally, miR96/183 and miR155 were found to target other inhibitory proteins of TCR signalling such as TET2, FOXO3 and PTPN2 which might have additional advantage to enhance T cell activation. Consistently, overexpression of miRNA96/183 enhanced IL-2 production while overexpression of miR155 enhanced both IL-2 production and CD69 expression on Jurkat T cells following anti-CD3/CD28 stimulation compared to controls with normal expression of respective microRNAs.
We revisited the tetracycline-inducible sleeping beauty system to expand miRNA overexpression approach in CAR T cell therapy and generated a vector to induce miRNA/coding gene overexpression in the presence of tetracycline while constitutively expressing second generation HER2 CAR. To study the effect of miRNA overexpression in HER2 CAR in primary human T cells, a third-generation lentiviral system was also optimised by exploring both single and dual promoter systems to co-express non-coding (miRNA) and coding genes (HER2-CAR and GFP) from the same vector. Although cytokine production (IL-2 and IFN-γ) and CD69 expression were similar between HER2 CAR±miRNA transduced T cells when co-cultured with HER2 positive MCF-7 cells, the profile of phenotypic marker expression was different.
Overall, this thesis demonstrates that the miRNA overexpression in T cells could be a useful approach to combat intrinsic inhibitory molecules. The modified sleeping beauty vector and the lentiviral vectors developed in this study can be utilized to combine CAR T cell therapy with other approaches to enhance the efficacy of the treatment in cancer immunotherapy. Therefore, this thesis provides useful resource for the development of various strategies in future to enhance the efficacy of anti-cancer T cells or CAR T cells in solid tumour
Motion measurement algorithms for MARS imaging
No full textThe goal of the MARS molecular imaging team is to advance medicine by researching, developing, and commercialising spectral CT systems. This thesis presents the work I performed to facilitate live imaging with MARS scanners. This aim was achieved by developing a gating algorithm, designing and developing a mouse holder, and creating a motorised motion phantom. My gating algorithms will contribute to improving the image quality of human data obtained by human-scale MARS scanners.
I contributed to the design and development of a mouse holder with a temperature regulating system that is compatible with MARS scanners for the purpose of live animal imaging. This holder design provides simple animal handling, secure positioning, anaesthesia delivery, regulated temperature control, and physiological monitoring.
I developed a post-acquisition automatic gating method based on the acquired scan data over time. This method is capable of identifying various movement phases to sort the acquired exposure images into temporal bins. To reduce the undersampling noise due to gating, a weight-based reconstruction algorithm was introduced and implemented. Instead of binning the data, this method employed all images for the reconstruction of specific time points by assigning a weight to each. The result of applying this method showed that it can improve the undersampling artefacts compared to the temporal binning method.
To evaluate the gating method, a motorised motion phantom was designed and manufactured. The motion phantom could be programmed to produce periodic signals with a similar frequency and amplitude to that of a mouse or human breathing. The quantitative measurements showed that gating can reduce motion artefacts and blurring by 50% with a 1mm amplitude and 26% for a 5mm amplitude.
The effect of motion on the material decomposition process in MARS imaging systems was investigated. Known contrast agents were added to the motion phantom and then scanned with movements with the amplitude of 1 to 5 mm. No clear trend between the motion amplitude and the material decomposition accuracy was observed. The gated images had lower SNR compared to the non-gated data, resulting in more misidentified voxels. This suggests that noise properties are more important than motion blur.
In summary, the research documented in this thesis facilitates live imaging in MARS scanners in the future
Mechanisms of bactericidal action and β-lactam synergy by the zinc ionophore PBT2
No full textThe emergence and global spread of antimicrobial resistance (AMR) is an increasingly serious threat to human and veterinary medicine. Driven by the misuse and overuse of antibiotics, resistance to our antibiotic armoury is rapidly outpacing our current efforts to discover and develop novel agents. In light of this, there is restimulated interest in exploiting metals for novel antibacterial strategies. Zinc is an essential metal ion for various cellular pathways in bacterial physiology, yet excess amounts are toxic. The involvement of zinc in modulating antibiotic efficacy and resistance pathways is also becoming increasingly evident. Zinc ionophores, molecules that transport zinc into cells, offer a strategy to capitalize on the anti-infective potential of this metal. The zinc ionophore PBT2, an 8-hydroxyquinoline derivative, has recently been discovered to potentiate zinc toxicity and antibiotic efficacy against several AMR pathogens, suggesting possibilities for zinc ionophores as a novel class of standalone antibiotic or antibacterial adjuvant in either animal or human medicine. A molecular understanding of these actions, however, is currently lacking. This body of work examines the bactericidal action of PBT2 against the veterinary pathogen Streptococcus uberis, and the underlying mechanism of synergy between PBT2 and β-lactam antibiotics against methicillin-resistant Staphylococcus aureus (MRSA).
A combination of bacterial physiology, biochemistry, genetics, and chemical biology approaches were utilised to investigate the mechanisms of zinc ionophores in both lines of this research. We revealed PBT2-mediated intracellular zinc accumulation disrupts zinc and manganese homeostasis and cellular redox balance in S. uberis, ultimately exerting its bactericidal action through intracellular zinc accumulation and manganese starvation, ROS accumulation, and the impairment of manganese-dependent antioxidant activity. We further demonstrated that β-lactam antibiotic resensitization in MRSA by PBT2 and related structural analogues is likewise associated with a destabilization of cellular zinc and manganese homeostasis. Mechanistic investigations revealed this zinc ionophoric activity perturbs multiple elements involved in β-lactam resistance in MRSA, including the expression of key resistance determinants, cell wall and membrane integrity, and the proton motive force (PMF). Further, PBT2 and β-lactam combination treatment significantly improved animal survival rates and pathogen clearance in a murine model of invasive MRSA infection. This study provides novel mechanisms of intracellular zinc toxicity and demonstrates a targetable overlap between metal homeostasis, cell wall and membrane metabolism and β-lactam resistance. Overall, this data contributes and adds to the field of bacterial metal homeostasis and exemplifies how it can be exploited for novel antibacterial strategies in veterinary and human medicine
Development and preclinical evaluation of an oral therapeutic colorectal cancer vaccine
No full textColorectal cancer (CRC) has become the second most common cause of cancer death worldwide, indicating the need for novel therapies to reduce mortality rates and the global burden of this disease. Therapeutic subunit vaccines are a safe and promising method for the treatment of established cancers. These vaccines aim to stimulate the patient’s immune system to recognize and eradicate malignant cells. Robust immune stimulation is necessary to maximize the therapeutic potential of the cancer vaccines and in the case of CRC, this can be achieved via oral vaccine administration. Anti-tumour immune responses can then be initiated at the tumour location, specifically, at the lymphoid tissues of the gastrointestinal tract. However, vaccines delivered orally require protection from the harsh conditions found in the gastrointestinal tract. This protection can be provided through the use of appropriate delivery systems, which also facilitate the addition of vaccine adjuvants.
The hypothesis of this research was that orally delivered therapeutic subunit cancer vaccines in lipid-based formulations stimulate local and systemic anti-tumour immune responses that would lead to CRC elimination in a preclinical orthotopic mouse model.
The hypothesis was tested initially with oral subunit vaccine formulations composed of a peptide containing epitopes for CD8+ and CD4+ T cells, in combination with the Toll-like receptor 2 (TLR2)-stimulating adjuvant, Pam2Cys. These formulations were encapsulated in liposomes and in water-in-oil-in-water (W/O/W) double emulsions. Following optimisation of the formulations, the emulsion vaccine induced local immune cell accumulation and systemic lymphocyte activation after oral vaccination. Furthermore, both emulsion and liposome vaccines demonstrated therapeutic potential by significantly reducing the growth of CT26 tumours injected intracaecally into mice. The findings confirmed that positive therapeutic effect can be achieved with oral subunit vaccines delivered in lipid-based formulations.
Although both vaccine candidates demonstrated promising treatment outcomes, they were not able to completely eliminate the tumours. Therefore, a number of modifications were made to the vaccine and/or the therapy including; using self-adjuvanting peptides, modifying liposomes for targeted delivery, and combination therapy with a nonsteroidal anti-inflammatory drug (NSAID) with or without an immune checkpoint inhibitor. The self-adjuvanting construct was not effective when delivered orally or with lipid-based formulations, underlining the need to further investigate the immunostimmulatory activity of these constructs as oral vaccines. Targeting of liposome to M cells with the Ulex europaeus agglutinin I (UEAI) lectin also did not improve therapeutic outcomes. It was not clear if this was due to the lectin not improving liposome uptake by the M cells or if improved uptake had occurred but was not translated into therapeutic effect. Combination therapy with the NSAID licofelone was the most promising strategy with a partial response to vaccination and reduced tumour growth. The addition of the checkpoint inhibitor anti-programmed cell death protein 1 (PD-1) was of no benefit in this mouse model. This is likely due to insufficient lymphocyte infiltration into the tumour.
A novel technique utilising bacterial ‘microswimmers’ to improve the delivery and immunogenicity of the oral vaccines, was explored and adapted for the preclinical evaluation of immunotherapeutic CRC treatment. Escherichia coli (E. coli) were attached to liposomes or emulsion vaccine particles and used as an oral vaccine microsystem. Microswimmer vaccines were not toxic and demonstrated favourable immunostimulatory profiles in cell culture, as expected due to the natural pathogen associated molecular patterns (PAMP), which could interact with pattern recognition receptors (PRR) on dendritic cells (DC). Improved therapeutic outcomes were observed after treatment with emulsion microswimmers in mice, confirming that bacteria can be a powerful immunostimulatory agent and boost immune responses to orally delivered vaccine antigens. Although tumour growth was reduced with the emulsion microswimmers, the liposome microswimmers did not demonstrate the same effect. The likely reason for this is the stability of the bacterial attachment.
The study evaluated strategies for the treatment of established colorectal tumours with oral subunit vaccines administered in lipid-based formulations. The preclinical vaccine development study provided important insights for the future investigation of therapeutic oral CRC vaccines. The findings confirmed the potential of these vaccines to be used in human therapy as the vaccine candidates demonstrated immunostimulatory and therapeutic capacity to induce multiple anti-tumour immune responses and reduce tumour growth. The emulsion vaccine candidate is being further investigated for use in clinical trials as it produced the best results and is easier to make, facilitating its transition into the clinic
Teaching analytics and teacher dashboards to visualise SET data: Implication to theory and practice
No full textTeaching Analytics (TA) is an emergent theoretical approach that combines teaching expertise, visual analytics, and design-based research to support teachers' diagnostic pedagogical ability to use data as evidence to improve teaching quality. The thesis is focused on designing dashboards to help teachers visualise Student Evaluation of Teaching (SET) data as a form of TA for improving the quality of teaching. The research examined the role of TA by deploying customisable dashboards to support teachers in using data to design and facilitate learning. The researcher carried out an integrated literature review to explore the notion of TA and SET data. Moreover, a Data Science Life Cycle model was proposed to guide teachers and researchers using SET data to improve learning and teaching quality. The research comprised several phases. In phase I, a simulated data technique was used to generate SET scores that informed the development of a preliminary teacher dashboard. Phase II surveyed teachers' use of SET data. The survey results indicated that more than half of the participants used SET for improving teaching practice. The research also showed that participants valued the free-text qualitative comments in SET data. Hence, phase III collected real free-text qualitative comments in SET data on students' perceptions of a previously tutored course. The survey results further indicated that although teachers were unaware of a dashboard's value in presenting data, they wanted to visualise SET data using dashboards. Phase IV redesigned the preliminary dashboards to present the real SET data and the simulated SET scores. Finally, phase V carried out usability testing to evaluate teachers' perceptions of usability and usefulness of the teacher's dashboards. Overall, the result of the usability study indicated the perceived value of the teacher's dashboards
Discoveries from the alpine daisy Celmisia viscosa: unique diterpenes and flavones, and variation within the species
No full textThis thesis focuses on the natural product chemistry of the native Alpine daisy, Celmisia viscosa. Previous work on C. viscosa has shown the presence of the diterpenes epimanool and the rare halimadienol, also present were these compounds with a new glycoside attached. There were indications of these and related compounds in other New Zealand Celmisia species. This study aimed to investigate variation among Celmisia and to isolate and characterise the major novel compounds associated with variation. Using C. viscosa, a repeatable method of CDCl3 extraction and NMR and GC analyses from small quantities of leaf material has been established. This allowed for the investigation of chemical variation using portions of stored botanical voucher specimens, extracts of which were subjected to Principal Component Analysis (PCA). Variation among eight species of Celmisia was investigated, with results indicating that C. viscosa stands out, having generally the highest secondary metabolite concentrations and intraspecific variation.
Investigation of variation within a C. viscosa plant sourced from End Peak, Harris Mountain found the leaves to contain the highest concentration of diterpenes. Further investigation, of C. viscosa leaves from three plants from the same region indicated only variation in diterpene concentration, not diterpene type. C. viscosa leaf material was sourced from herbaria, giving access to nearly the full geographic range of C. viscosa from different regions around South Island, New Zealand. Results indicated the presence of two distinct chemotypes.
Isolation of the major compounds from each chemotype gave epimanool and the reported epimanool glycoside, 2’,6’-dideoxy-hexopyran-3’-ulose isolated from CHCl3 leaf extracts from the Kakanui Ranges. Halimadienol plus two novel derivatives, halimadienol 4’-acetyl-2’,6’-dideoxy-hexopyran-3’-ulose and halimadienol-4’-hydroxy-2’,6’-dideoxy-hexopyran-3’-ulose were isolated from CHCl3 leaf extracts from the Rock and Pillar Ranges. Halimadienol has been also reported from Jungermannia infusca and Plagiochila barteri, but it was not fully characterised. The data herein presents the full characterisation of halimadienol with X-ray crystallography revealing the absolute stereochemistry.
NMR Spectroscopic data indicated halimadienol to be conformationally mobile, but subjecting the compound to 13C NMR at various temperatures failed to give access to the slow exchange conformation. However, computational modelling revealed two significant conformers, the major of which matched that of the crystal structure. 2D NMR and spectroscopic data for the halimadienol 4’-acetyl-2’,6’-dideoxy-hexopyran-3’-ulose, previously isolated, but not published, is presented herein. Isolation of halimadienol-4’-hydroxy-2’,6’-dideoxy-hexopyran-3’-ulose gave the opportunity for the absolute stereochemistry of the glycoside moiety to be deduced using Mosher ester analysis. Halimadienol-4’-hydroxy-2’,6’-dideoxy-hexopyran-3’-ulose was acetylated to further confirm the stereochemistry.
Halimadienol and epimanool have quite different retention indices and times with halimadienol eluting earlier from GC-FID-MS column. This behaviour suggested that the halimadienol could be thermally degrading upon injection onto the GC column. A study of the behaviour of these compounds upon injection onto a column at various temperatures failed to verify this assertion, so halimadienol was chemically dehydrated, with the products being reinjected onto GC, thereby refuting the hypothesis.
Three novel acylated trimethoxyflavones: 8-(3”-methylbutanoyl), 5-hydroxy-5,7,4’-trimethoxyflavone, 8-(2”-methylbutanoyl), 5-hydroxy-5,7,4’-trimethoxyflavone and 8-(2”-methylpropanoyl), 5-hydroxy-6,7,4’-trimethoxyflavone were discovered in a bulk CHCl3 extract of leaves from the Rock and Pillar Ranges. Characterisation of these compounds was achieved by 2D NMR, comparison to model compounds and X-ray crystallography. Subsequent structural elucidations of a mixture of four novel acylated dimethoxyflavones: 8-(2”-methybutanoyl), 5,4’-dihydroxy-6, 7-dimethoxyflavone; 8-(3”-methybutanoyl), 5,4’-dihydroxy-6,7-dimethoxyflavone; 8-(2”-methybutanoyl), 5,7-dihydroxy-6,4’-dimethoxyflavone; 8-(3”-methybutanoyl), 5,7-dihydroxy-6,4’-dimethoxyflavone and a mixture of two novel acylated monomethoxyflavones: 8-(2”-methylbutanoyl),5,7,4’-trihydroxy-6-methoxyflavone and 8-(3”-methylbutanoyl),5,7,4’-trihydroxy-6-methoxyflavone were made using the trimethoxyflavones as model compounds. X-ray crystallography of 8-(2”-methylbutanoyl),5,7,4’-trihydroxy-6-methoxyflavone confirmed the proposed structures. An ethanol extract of C. viscosa leaf material from Mount Harris gave the two major dimethoxyflavones; 8-(2”-methybutanoyl), 5,4’-dihydroxy-6,7, dimethoxyflavone; 8-(3”-methybutanoyl), 5,4’-dihydroxy-6,7, dimethoxyflavone in a 2:1 mixture allowing for partial 2D NMR assignment of both compounds. Analysis of the seven other species of Celmisia indicated novel flavone profiles and analysis of the full range of C. viscosa leaf extracts by HPLC indicated the presence of flavone chemotypes.
While this work has increased the chemical knowledge of C. viscosa a range of further work remains for both the species and the genus. Further analysis of the chemical variation of viscid species of Celmisia regionally may uncover further species exhibiting chemotypic variance, while bulk extraction may lead to the discovery of other novel diterpenes. More within site leaf extract analysis may uncover differing chemotypes within plants in proximity. If more bulk C. viscosa from other regions is sourced, extraction and isolation may provide evidence of more novel diterpene derivatives. Ecological studies with halimadienol and epimanool may provide insight around the function of these compounds. Assessment of the contents of trichomes, found on the flowers of C. viscosa, would confirm whether these structures contain flavones or diterpenes
Dietary intakes and major food sources of vitamin B12 among New Zealand adolescent males and females
No full textBackground: Adolescence is a period of rapid growth and thus, is an essential time for ensuring adequate intake of all nutrients. Vitamin B12 in particular, is an essential nutrient for DNA synthesis, red blood cell formation and neurological function. Based on data from the 2008/09 New Zealand Adult Nutrition Survey, vitamin B12 intake of New Zealand adolescents were shown to be largely adequate, however, changes in dietary patterns over the last 10 years may have negatively impacted the major dietary contributors of vitamin B12 intake. In particular, with global trends emphasizing plant- based diets and the subsequent decline in consumption of milk and animal source foods, it is currently unclear what New Zealand adolescents are eating. As vitamin B12 is naturally found in food of animal origin, young adults that choose to omit animal products are at increased risk of deficiency.
Objective: The aim of the present study was to evaluate dietary vitamin B12 intake, and its major food sources among female and male adolescents aged 15-18 years.
Methods: The present study was part of a larger nutrition assessment project; the Survey of Nutrition Dietary Assessment and Lifestyle (SuNDiAL). SuNDiAL was designed as a clustered, cross-sectional study of 401 female and male adolescents nationwide. Recruitment of participants and data collection took place in 19 secondary schools across ten different regions in New Zealand between February 2019 and April 2020. Eligible participants provided information of their demographic and health status; dietary habits and vegetarian status; and attitudes, motivations and beliefs regarding food choices via online self-administered questionnaires. Anthropometric measurements including height and weight were taken, and BMI (kg/m2) and BMI z- scores were determined. Dietary intake information was collected via two 24-hour recalls on non-consecutive days (the first face-to-face, the second by telephone or video link) within two weeks. Food recall data were entered into a nutrient analysis software programme, FoodWorks 9 to calculate energy and vitamin B12 intake. Energy and dietary vitamin B12 intakes were adjusted for within person variation using the Multiple Source Method to represent usual intakes. Nutrient adequacy was assessed using the EAR cut-point method.
Results: The sample population consisted of 266 females and 135 males self- identifying as New Zealand European or Other (71.2%), Māori (13.7%), Asian (12.7%) and Pacific (2.3%). Only 9% of the sample population reported adopting a vegetarian lifestyle, with a high proportion of vegetarians among female participants compared to males (11% vs 4%, respectively). Usual dietary vitamin B12 intakes were found to be higher in males at 3.8 μg/day compared to that of females at 2.5 μg/day. In addition, inadequate vitamin B12 intake (below <2.0 μg/day) was higher in females (22.6%) than males (10.8%). However, participants who reported following a vegan (n=6) or vegetarian dietary pattern (n=23) showed the highest prevalence of inadequate vitamin B12 intake at 83.3% and 34.8%, respectively. Lastly, the top three major food group contributors of vitamin B12 were foods of animal origin among both females and males; milk, beef and veal, poultry representing 28.3% and 40.5% of total dietary vitamin B12 intake, respectively.
Conclusion: Vitamin B12 intakes in adolescents are largely dependent on consumption of animal products. Majority of participants were achieving their daily recommended requirement (>2.0 μg/day) albeit inadequacy was higher among females and those reporting vegan and vegetarian lifestyles. Consumption of fortified alternatives or supplements may be recommended to attenuate the higher prevalence of inadequate intake among at risk groups
Stabilizing laser diodes with an optical feedback from a whispering gallery mode resonator
No full textStabilization of optical sources are becoming more important in high precision measurements. Whispering gallery mode resonators are an ideal candidate for a cavity to stabilize laser diodes. Imperfections in the resonator act as scattering centers and reflect resonant modes, which allows the self-injection locking of the laser diode.
The work presented here studies the effect of optical feedback on distributed feedback and Fabry-Perot lasers by looking at the linewidth and stability. The resonator was fabricated from a lithium niobate crystal, which the quality factor was measured at 6.92 × 107. Linewidth was measured with two different self-heterodyne methods, both using an acoustooptic modulator of 100 MHz to induce a frequency shift. The first regime was the traditional method where the unmodified beam is delayed by a significant path length. The second was a modified method which recycles a portion of the heterodyne through the delay and acousto-optic modulator. This effectively increases the delay length by creating integer multiples of the beat frequency. The linewidth of the distributed feedback laser was measured has decreased from 63.9 kHz to 10 kHz with the feedback.
Stability of the Fabry-Perot laser was measured by calculating the Allan deviation. The Fabry-Perot laser was mixed with a reference ECDL with some offset frequency and the beat signal from the photodector was analysed by an oscilloscope. The Allan deviation was caculated by performing a fast Fourier transform at different averaging times. The Allan deviation of the Fabry-Perot laser decreased from 6022 Hz to 4089 Hz at the averaging time of 0.1 ms. Furthermore, the linewidth was calculated at the same averaging time, which decreased from 37.3 kHz to 33.2 kHz
Health and wellbeing of under-25 year olds in Nelson Marlborough and South Canterbury 2019
No full textIn this report the New Zealand Child and Youth Epidemiology Service (NZCYES) presents information to assist in the planning and funding of services that can collectively improve, promote and protect the health and wellbeing of children and young people aged under-25 years. This is the final of three age-based reports: indicators presented in 2017 had a focus on the first five years of life, and the 2018 report had a focus on the health and wellbeing of under-15 year olds.
Data for the indicators presented in this report were extracted in 2019 from a range of routinely collected national datasets. The report provides an analysis of the most recent data available for each indicator at the time of writing. Unadjusted rates should be interpreted in light of the differing patterns in age structure, ethnic composition, social and material deprivation in each DHB and in Aotearoa overall. Evidence for good practice is presented for each section, compiled from published scholarly literature and from publicly available guidelines, policies, and reports. Where possible, the evidence for good practice includes discussion of equity issues relevant to each indicator, to inform service planning and delivery.
The two review topics included in this report were selected by DHB representatives: Alcohol use in young people by Lee Smith and Promoting mental wellbeing in schools by Judith Adams and Georgia Richardson. These two sections of the report can inform strategies to promote health and wellbeing for all young people. Intervention and treatment services, supportive environments, and healthy cultural norms around drinking are some key components to addressing hazardous alcohol consumption in Aotearoa’s youngest generations. Through school-based initiatives, services can support the mental wellbeing of children and adolescents and thus invest in their long-term flourishing.
Navigating sexual and reproductive health is important to the lives of many young people. Information on reproductive planning and pregnancy rates can provide an indication about the accessibility of services and provide an indication about the future social and economic participation of this generation of young people and the sustainability of the overall population and economy.1 These indicators are presented in the section on Reproductive health.
The section on Mental Health presents information on the prevalence of selected mental health diagnoses in young people, the mental health services utilised by young people and the hospitalisations of young people that are associated with mental health issues.
Selected indicators about substance use and smoking, alcohol and drug service utilisation, and alcohol and drug hospitalisations are presented in the Substance use section. These indicators are important for overall wellbeing, growth, and long-term health of children and young people and inextricably linked to other wellbeing measures presented in the 2019 report.
The United Nations Convention on the Rights of the Child establishes that every child is deserving of a state-level commitment towards the promotion of their social, spiritual and mental wellbeing, as well as towards their protection from all forms of violence and harm.2 The section on Safety and Security provides an overview of indicators relating to the protection of children and young people in Aotearoa, including information about assault and self-harm.
Supporting and adding value to the lives of children and young people with cancer is an important part of planning and funding decisions and is presented in the section on Cancer.
The report appendices describe the processes used in compiling information for these reports, including the methods used to develop evidence for good practice, and the statistical methods used in the data analyses. The appendices give further information about the data sources used for the indicators in the report, explanation about classification of ethnicity and social and material deprivation, and a list of the clinical codes relevant to each indicator.
In summary, the 2019 report on health and wellbeing of under-25 year olds presents data and interpretation on a set of relevant indicators extracted from national health datasets. The data used were the most recent available at the time of writing, and provide a snapshot of achievements and challenges in these areas. This report cannot address questions that require outpatient data, as these are not yet available at a national level. Developing systems that can provide a fuller picture of outpatient and primary health care data is important to inform child health service planning at national and DHB levels. The NZCYES is liaising with the Ministry of Health as they develop and roll out a patient flow system that will include primary care and outpatient data