title: Identifying iron-binding antioxidants in New Zealand honeydew honey

authors: Omar, Syaliza Binti

subjects: antioxidants

abstract: Iron is an essential element for human physiological function. However, excess free iron could participate in the formation of reactive oxygen species via the Fenton reaction and is thought to be the primary mechanism for the pathogenesis of diseases related to iron excess. Prevention of the oxidative damage caused by reactive oxygen species can be accomplished by using selective iron-binding compounds. Beech honeydew honey has been found to have an exceptionally high level of iron-binding antioxidant activity. Due to that, the focus of the research in this thesis has been to isolate the compound(s) responsible for the activity and identify their molecular structure.
The stability of the antioxidants on exposure to heat and high and low pH was investigated to get a better understanding of the conditions which could be used when developing suitable techniques for the isolation of the iron-binding antioxidants. 
The isolation of the antioxidants was first attempted with XAD-2 resin. The results of solid phase extraction using XAD-2 resin showed that the activity is mainly found in the honey effluent, the fraction not retarded by the resin, indicating that hydrophilic components contributed to the iron-binding antioxidant activity. The phenolic compounds isolated from this resin did not exhibit iron-binding antioxidant activity.
When the antioxidants could not be isolated from the XAD-2 resin, size exclusion chromatography was used to separate the honey components based on their molecular sizes. The technique was successsful in separating antioxidants from free sugars in honey. However, size exclusion chromatography did not give any significant information regarding the identity of the antioxidants. Thus, two types of chromatography (reversed phase and anion exchange) were used in sequence to aid the separation of components of the active fraction from size exclusion chromatography. This procedure however was not compatible with subsequent mass spectrometry since a high level of sodium chloride existed in the final fraction, even after desalting using reversed phase column chromatography. Due to that, other means of chromatography were trialled in order to obtain a salt-free fraction prior to mass spectrometry. The first procedure was modified by switching the sequence of the columns used, and different mobile phases without salt were used. This second procedure was successful in isolating the antioxidants and the compounds have been characterised by mass spectrometry.
Mass spectrometry revealed that the antioxidants isolated were compounds of low molecular weight (i.e. 255, 283 and 227) which exhibited peaks with high intensity. Nuclear magnetic resonance (NMR) spectroscopy of the active fraction showed that the antioxidant may possess a 1,4-disubstituted aromatic ring. However, full elucidation of the structure of the compound was not possible because of the very low mass of the material that had been isolated. 
Other than the information gained from mass spectrometry and NMR, the antioxidant also could be characterised by forming the negative ion at pH 9.5–10. The UV absorbance at 220 and 280 nm, but not at 360 nm is indicative that the antioxidant possess a phenolic ring but not a flavonoid in the molecular structure.
Complete structural elucidation of the iron-binding antioxidants in honeydew honey could initiate a better understanding of the mechanism of action of the antioxidants. This could increase the use of honeydew honey in pharmaceutical and nutraceutical products as an iron-binding antioxidant. There is also the possibility that the identified compound(s) could be synthesised for pharmaceutical use, or serve as lead compounds for the development of other pharmaceutical iron-binding antioxidants.

text: Identifying iron-binding antioxidants in New Zealand honeydew honey Iron is an essential element for human physiological function. However, excess free iron could participate in the formation of reactive oxygen species via the Fenton reaction and is thought to be the primary mechanism for the pathogenesis of diseases related to iron excess. Prevention of the oxidative damage caused by reactive oxygen species can be accomplished by using selective iron-binding compounds. Beech honeydew honey has been found to have an exceptionally high level of iron-binding antioxidant activity. Due to that, the focus of the research in this thesis has been to isolate the compound(s) responsible for the activity and identify their molecular structure.
The stability of the antioxidants on exposure to heat and high and low pH was investigated to get a better understanding of the conditions which could be used when developing suitable techniques for the isolation of the iron-binding antioxidants. 
The isolation of the antioxidants was first attempted with XAD-2 resin. The results of solid phase extraction using XAD-2 resin showed that the activity is mainly found in the honey effluent, the fraction not retarded by the resin, indicating that hydrophilic components contributed to the iron-binding antioxidant activity. The phenolic compounds isolated from this resin did not exhibit iron-binding antioxidant activity.
When the antioxidants could not be isolated from the XAD-2 resin, size exclusion chromatography was used to separate the honey components based on their molecular sizes. The technique was successsful in separating antioxidants from free sugars in honey. However, size exclusion chromatography did not give any significant information regarding the identity of the antioxidants. Thus, two types of chromatography (reversed phase and anion exchange) were used in sequence to aid the separation of components of the active fraction from size exclusion chromatography. This procedure however was not compatible with subsequent mass spectrometry since a high level of sodium chloride existed in the final fraction, even after desalting using reversed phase column chromatography. Due to that, other means of chromatography were trialled in order to obtain a salt-free fraction prior to mass spectrometry. The first procedure was modified by switching the sequence of the columns used, and different mobile phases without salt were used. This second procedure was successful in isolating the antioxidants and the compounds have been characterised by mass spectrometry.
Mass spectrometry revealed that the antioxidants isolated were compounds of low molecular weight (i.e. 255, 283 and 227) which exhibited peaks with high intensity. Nuclear magnetic resonance (NMR) spectroscopy of the active fraction showed that the antioxidant may possess a 1,4-disubstituted aromatic ring. However, full elucidation of the structure of the compound was not possible because of the very low mass of the material that had been isolated. 
Other than the information gained from mass spectrometry and NMR, the antioxidant also could be characterised by forming the negative ion at pH 9.5–10. The UV absorbance at 220 and 280 nm, but not at 360 nm is indicative that the antioxidant possess a phenolic ring but not a flavonoid in the molecular structure.
Complete structural elucidation of the iron-binding antioxidants in honeydew honey could initiate a better understanding of the mechanism of action of the antioxidants. This could increase the use of honeydew honey in pharmaceutical and nutraceutical products as an iron-binding antioxidant. There is also the possibility that the identified compound(s) could be synthesised for pharmaceutical use, or serve as lead compounds for the development of other pharmaceutical iron-binding antioxidants.

year: 2013

title: Exploring the antecedents of intentions to leave the job: The case of luxury hotel staff

authors: Mohsin, Asad

subjects: staff turnover

abstract: The aim of this study is to assess the antecedents of employee’ intentions to resign from their jobs in luxury hotels in India. Two aspects are considered in this context: firstly, the employees’ enthusiasm for the profession and organisation, the nature of the work and its impact on social and family life. Secondly, their level of satisfaction with the job in terms of organisational loyalty, relationship with supervisors, job security, earnings and additional benefits. A theoretical model (see Fig. 1) and seven hypotheses are tested to indicate whether the employees’ level of agreement with statements about the job and their level of satisfaction with the job will impact their intentions to quit. The study further examines if any current employees intend to leave their job. The term luxury hotel is used to represent 5 star and 4 star hotels of India.
Findings from the analyses of 884 responses suggest that, when considering intentions to resign from the job, a negative relationship is found between professional and organisational enthusiasm and perceptions about the work being stimulating. No support was found for a positive relationship between the extent work impacted social and family life and the intention to quit. However, results supported the notion that the employee's organisational loyalty has a negative effect on his/her intention to resign from the job. Our findings contradict several other studies in that they suggest the employee's intention to resign from the job increases as job security and earnings improve. The study is distinctive as it explores intentions luxury hotel employees in India to leave their jobs; three is little evidence in the wider literature of similar attempts in the context of the Indian hotel industry. The outcomes have implications for both theory and practice as this is the first such major study in the context of the hotel industry in India where there is a population of over a billion people and an expanding hotel industry.

text: Exploring the antecedents of intentions to leave the job: The case of luxury hotel staff The aim of this study is to assess the antecedents of employee’ intentions to resign from their jobs in luxury hotels in India. Two aspects are considered in this context: firstly, the employees’ enthusiasm for the profession and organisation, the nature of the work and its impact on social and family life. Secondly, their level of satisfaction with the job in terms of organisational loyalty, relationship with supervisors, job security, earnings and additional benefits. A theoretical model (see Fig. 1) and seven hypotheses are tested to indicate whether the employees’ level of agreement with statements about the job and their level of satisfaction with the job will impact their intentions to quit. The study further examines if any current employees intend to leave their job. The term luxury hotel is used to represent 5 star and 4 star hotels of India.
Findings from the analyses of 884 responses suggest that, when considering intentions to resign from the job, a negative relationship is found between professional and organisational enthusiasm and perceptions about the work being stimulating. No support was found for a positive relationship between the extent work impacted social and family life and the intention to quit. However, results supported the notion that the employee's organisational loyalty has a negative effect on his/her intention to resign from the job. Our findings contradict several other studies in that they suggest the employee's intention to resign from the job increases as job security and earnings improve. The study is distinctive as it explores intentions luxury hotel employees in India to leave their jobs; three is little evidence in the wider literature of similar attempts in the context of the Indian hotel industry. The outcomes have implications for both theory and practice as this is the first such major study in the context of the hotel industry in India where there is a population of over a billion people and an expanding hotel industry.

year: 2013

title: “Seeing” Kāpō Māori: Making visible the experiences of Kāpō Māori during and after COVID-19

authors: Masters-Awatere, Bridgette

abstract: A scoping project focused on the intersection of Māori and the framing of vision impairments (disability) within the context of a pandemic response (in this instance COVID-19). Specifically, we were interested in the experiences of kāpō Māori during and post COVID-19 in order to centre the cultural and health needs of kāpō Māori in a culturally responsive manner. We highlight the aspirations that kāpō Māori have for themselves and their whānau, and to identify the facilitators and barriers that kāpō Māori and their whānau face in achieving these

text: “Seeing” Kāpō Māori: Making visible the experiences of Kāpō Māori during and after COVID-19 A scoping project focused on the intersection of Māori and the framing of vision impairments (disability) within the context of a pandemic response (in this instance COVID-19). Specifically, we were interested in the experiences of kāpō Māori during and post COVID-19 in order to centre the cultural and health needs of kāpō Māori in a culturally responsive manner. We highlight the aspirations that kāpō Māori have for themselves and their whānau, and to identify the facilitators and barriers that kāpō Māori and their whānau face in achieving these

year: 2021