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Effects of zinc fortification on the plasma fatty acid composition of beninese school children: A randomised, double-blind controlled trial
No full textIntroduction
The lack of a specific and sensitive zinc (Zn) status biomarker is problematic. The linoleic acid: dihomo-γ-linolenic acid (LA:DGLA) ratio has been suggested by some researchers to be a Zn status marker. This is because Zn and fatty acids (FA) are known to interact, as Zn and FA deficient individuals present similar symptoms and physical manifestations. Although the mechanism by which Zn and FA interact is not fully understood, it is suggested that they interact through the FA synthesis pathway. Zn deficiency is suggested to impair the activity of desaturase enzymes, (desaturase enzymes are responsible for the conversion of essential fatty acids into longer-chain polyunsaturated FA) thereby causing a decrease in tissue long chain polyunsaturated metabolites. Zn supplementation in Zn deficient rats is known to affect their FA status, but little is known about effects of Zn fortification on the FA status in humans. There is also limited data on the FA status of African children as well as data on Zn and FA interactions in humans. Therefore the main aim of this study was to investigate whether there were associations between baseline plasma Zn and plasma total phospholipid FA composition, as well as to assess the effect of Zn fortified water on the plasma total phospholipid FA composition of rural Beninese school children aged between 6 and 10 years.
Methods. In a 20-week double blind randomised controlled trial, Beninese school children from a low-income rural setting aged between 6 and 10 years (n = 185) were randomly assigned to receive either a 300ml daily portion of Zn-fortified filtered water delivering 2.8 mg Zn (Zn+filter) or non-fortified filtered water (Filter). Plasma total phospholipid FA composition was determined using capillary gas chromatography and plasma Zn (PZn) analysis by atomic absorption spectrometry. Associations between Zn and FA were examined at baseline. Furthermore, the effect of Zn fortification on plasma FA composition was analysed in the total group, as well as in the Zn deficient and sufficient children and in girls and boys separately.
Results and discussion. At baseline, plasma Zn correlated positively with DGLA (r = 0.209; p = 0.010) and the DGLA:LA ratio (r = 0.327; p < 0.001). There was a significant inverse association between plasma Zn and linoleic acid (LA) (r = –0.229; p = 0.005) and the arachidonic: dihomo-γ-linolenic acid (ARA:DGLA) ratio (r = –0.257; p<0.001). At baseline, LA (p = 0.017), eicosapentaenoic acid (EPA) (p = 0.002), n-3 docosapentaenoic acid (DPA) (p = 0.020), adrenic acid (p = 0.010) and the ARA:LA ratio (p = 0.020) differed between boys and girls. In Zn sufficient boys, gamma-linolenic acid (GLA) was higher (p = 0.020) and the DGLA:GLA ratio tended to be higher (p = 0.059) than in Zn deficient boys. Zn fortification increased nervonic acid (p = 0.048) and tended to reduce LA (p = 0.068) in all children. Zn deficient children had a significantly higher nervonic acid composition (p = 0.019) after Zn fortification, whilst no significant effect was found in Zn sufficient children (p = 0.382). Fortification did not improve the plasma total phospholipid FA composition differently in boys and girls.
Conclusion. The findings from this research therefore supports that the LA:DGLA (or DGLA:LA) ratio could be a possible biomarker for Zn status. Our results further demonstrated that Zn filtered fortified water had an effect on the plasma total phospholipid FA composition of children, and even more so in Zn deficient children, thereby indicating that elongation and desaturation might be improved by Zn. The plasma total phospholipid FA composition was affected more by Zn deficiency in boys than in girls. However, further research is required to fully confirm these results, as well to examine the underlying mechanisms that exist between Zn and FA in humansNational Research Foundatio
Culturally informed conceptions of traumatic experience and coping strategies among the mole-dagbon of Ghana
No full textCulture is important to an individual’s understanding of traumatic events and the symptoms that ensue after such events. Cultural understandings also inform how individuals cope with the traumatic stress symptoms they experience. A great deal is known about the understanding of traumatic experiences and effective coping mechanisms used in Western cultures, but non-Western cultures are generally understudied. Valuable lessons are learnt from conducting studies with understudied non-Western cultures. The research sought to explore and describe the culturally informed conceptions of traumatic experience and coping strategies in one such understudied population - the Mole-Dagbon of Ghana. The research used a qualitative exploratory descriptive interpretive methodology. Purposive nonprobability sampling was used to gain access to individuals who could comment on the knowledge objectives of the study. Data was collected using focus group discussions with cultural leaders, and semi-structured interviews with traumatized individuals. All interviews were audio-recorded, transcribed, translated and analyzed using interpretive phenomenological analysis. The findings indicated that traumatic experiences and the coping strategies are influenced by a number of cultural factors. Participants’ understanding of traumatic experiences and symptoms relied heavily on normative traditional African cultural understandings, but explanations also utilized monotheistic (from Islam and Christianity) worldviews. It was also evident that not all explanations were purely spiritual and events and symptoms were also explained using a natural/scientific framework. Some aspects of this system indicated parallels with the Western cognitive understanding of traumatic stress symptoms. The Mole-Dagbon did not focus naturally on explaining the events and symptoms and in the current sample such explanations were often deferred to authoritative individuals in the society (especially the soothsayers from the Traditional African Religion). However, there was an easy focus on coping with the symptoms after a traumatic event and in this last aspect there was a great degree of agreement between participants. A clear hierarchy of coping emerged with community and family social support being considered the most important aspect. Irrespective of religious affiliation, individuals also considered a visit to the soothsayer and completing prescribed rituals as important in the process. Even where an individual did not wish to include this practice from African Traditional Religion because of religious affiliation, they acknowledged the existence and effectiveness of these practices. Finally, it was thought important that a traumatized individual consult a religious leader for counselling (again irrespective of the actual religion). While there were elements of cognitive understanding and a recognition of counselling by religious leaders, Western based treatment modalities were not mentioned as options for the treatment of the symptoms of PTSD. Practitioners that come into contact with the Mole-Dagbon may need to use collaborative treatment strategies that respects and utilizes cultural treatment strategies for PTSD. One interesting element that needs further exploration is whether the cognitive understandings of the Mole-Dagbon can be used in a cognitive therapeutic paradigm. Even though these cognitive appraisals are present in explaining symptoms, there are no direct cultural remedies that rely on them.National Research Foundatio
A 4-day test weighing study to assess volume and variations in fat and energy content of breast milk
No full textExclusive breastfeeding is recommended for the first six months of life. Breast milk intake and
composition not only vary between populations and individuals, but also within feeds, within
days and between days. Very limited information is currently available on the breast milk intake
of exclusively breastfed infants, as well as on the energy and fat composition of breast milk from
lactating women in South African.
Aim:
The aim of this study was to assess breast milk intakes, as well as energy and fat concentration
of breast milk in a convenience sample of exclusively breastfed infants and their mothers from
Potchefstroom in South Africa. Furthermore, the study determined within-feed, diurnal and
between-day variations in energy and fat concentration of breast milk.
Methodology:
Twenty-four healthy mothers and their exclusively breastfed two to five-month old infants were
recruited to stay at the metabolic unit of the North-West University in South Africa for a period of
five days. The first 24 hours served as a run-in period and the remaining four days (96 hours)
served as the actual test weighing period. Infants were weighed (± 1 g accuracy) before and
after each feed to determine breast milk intake. A foremilk sample was collected before each
feed to determine energy and fat concentration of the milk using the creamatocrit method.
Additional mid-feed and hind-milk samples were collected from the first feed each day.
Results:
Mean breast milk intake was low (369 ± 98 g/day), and infants consumed 52 ± 15 g of milk at
each feed. Mean breastfeeding frequency was 7 ± 1 feeds/day. Mean fat and energy
concentrations of sampled foremilk were 25.7 ± 7.3 g/L and 2544.5 ± 255.9 KJ/L, respectively.
Mean daily fat and energy intake calculated from the measured milk intake was 14 ± 4g and
1096 ± 302 KJ, respectively. Fat concentrations of fore- (26.8 ± 8.2 g/L), mid- (37.6 ± 7.0g/L)
and hind-feed- (50.2±10.4 g/L) milk differed significantly (P<0.001). Consequently, energy
concentrations of fore- (2522.9 ± 323.2 KJ/L), mid- (2947.1 ± 275.3 KJ/L) and hind-feed (3463.5
± 409.6 KJ/L) milk differed (P<0.001). Milk fat concentration was significantly lower at night than
the evening (P=0.015).Milk energy concentration was significantly lower at night than the
morning, day and the evening (P<0.05). There were no differences in breast milk intake (grams)
between the four days (P=0.371). However, breast milk fat and energy concentration was significantly lower at day 4 than at days 1 and 3 (P<0.05). Prevalence of stunting, underweight
and wasting amongst the infants were 39.1%, 13.6% and 4.8%, respectively.
Conclusion
Breast milk and consequently energy intakes were low in this small sample of exclusively
breastfed South African infants. This may explain the high prevalence of stunting. However, the
change of environment and feeding pattern during the study could have affected milk production
or intake. Furthermore, test weighing may not be a well-suited method for establishing milk
intake in this population. Our results further confirm significant within-feed differences in breast
milk fat and energy concentrationNational Research Foundatio
The effects of fertilization with bio-digester slurry and the inclusion of carbohydrate additives at ensiling on the nutritive value of napier grass (pennisetum purpureum) silage
No full textThe objective of the study was to determine the effects of fertilisation with bio-digester slurry and
the inclusion of carbohydrate additives at ensiling on the fermentation characteristics, chemical
composition, ruminal degradability, and in vitro digestibility of Napier grass silage. Napier grass
planted at the School of Agriculture Experimental Farm, University of Venda in 5 m x 4 m plots
replicated three times in a completely randomised design and was irrigated with either biodigester
slurry or no bio-digester slurry (tap water) for a period of 12 weeks. After 12 weeks, the
Napier was freshly cut and ensiled for 90 days in 1 litre glass jars in a 2 (Control - tap water and
slurry irrigation) x 4 (No additive, molasses, maize meal and brown sugar) factorial arrangement.
Fermentation quality and nutritive composition were determined using standard protocols. The
dry matter (DM) and crude protein (CP) ruminal degradability was determined in sacco by
incubating feed samples in nylon bags (external dimension: 6 × 12 cm, pore size of 46 μm) in the
rumen in three Bonsmara steers fitted with rumen cannulae for 0, 6, 12, 24, 48, 72, 96 and 120
hours (h). Parameters to describe the dynamics of ruminal degradability of DM and CP were
obtained by fitting the data on the exponential equation P = a + b (1 - e-ct) using the NEWAY
computer program, where “a” is the rapidly degradable fraction, “b” is the slowly degradable
fraction and “c” is the outflow rate. The in vitro DM and CP degradability of rumen undegradable
residue collected after 12, 24 and 48 h incubation was determined by sequential digestion in
pepsin (abomasal) and pancreatin (small intestine) solutions. Fertilisation with bio-digester slurry
increased (P <0.05) CP content of fresh cut Napier grass pre-ensilage. Bio-digester slurry
fertilisation with molasses inclusion improved (P <0.05) the silage DM content which improved (P
>0.05) fermentation characteristics with pH of 4.2 and lowest NH3-N of 13.3 g/kg. Other chemical
compositions and fermentation characteristics were not affected (P >0.05) due to fertilisation x
additives treatment combinations. No bio-digester slurry fertilisation with maize meal inclusion
increased (P <0.01) DM degradability at 0 h incubation. As time progressed to 24 h, no biodigester
slurry fertilisation with no additive included reduced (P <0.01) DM degradability with no
difference (P >0.05) on other treatments. Potential DM degradability (a + b) of no bio-digester
slurry fertilisation with no additive inclusion silage was reduced (P <0.01). The reduction was
associated with low levels (P <0.01) of slowly degradable fraction “b”. In vitro DM and CP
digestibility were not affected (P >0.05) due to fertilisation x additives treatment combinations. In
conclusion, bio-digester slurry application improved the quality of fresh cut Napier grass, with the
combination of bio-digester slurry fertilisation and molasses addition yielding the best silage
quality.National Research Foundatio
Investigating sputtered thin film Pt-containing electrocatalysts for SO2(aq) electro-oxidation
No full textEnvironmental concerns, social, economic and political pressure, and new technologies are the main factors
driving change in energy systems around the globe. Human life and development are inevitably dependent
on energy and the world is currently significantly reliant on mainly fossil fuels to meet its energy
requirements. Fossil fuels together with nuclear energy both have negative implications for the health of
humans and the quality of the environment. A worthy competitor that can serve as a solution to the depleting
and destructive nature of fossil fuels and nuclear energy is renewable energy. Hydrogen, not only a noncarbon-
containing energy carrier, but the most abundant atom on earth is considered the ultimate clean
energy carrier to be generated from renewable resources. As hydrogen is only found as part of compounds
on earth, it is fairly energy intensive to separate hydrogen into its molecular form, which goes hand in hand
with huge amounts of environmental pollutants being emitted to the atmosphere. The hybrid sulphur (HyS)
cycle, a thermo-electrochemical water splitting process, through the electrochemical oxidation of SO2,
serves as a means of producing hydrogen in a usable form without emitting any harmful pollutants.
Although there are various ways to produce hydrogen, interest in the non-carbon-based HyS cycle as a
potential large scale hydrogen production process, results from the fact that, whereas the anodic reaction
for regular water electrolysis, as another means of producing hydrogen, occurs at a standard potential of
1.23 V (SHE), the anodic reaction in the SO2 depolarised electrolyser (SDE1) occurs at a standard potential
of 0.17 V (SHE), which translates into an energy gain of more than one volt that makes the HyS cycle more
favourable. Insufficient electrocatalyst activity, stability and economic viability are among the most
challenging issues related to technologies for electrochemical energy conversion. An aspect that can
improve the SDE performance and economic viability is improving the anodic reaction of electrochemically
oxidising aqueous SO2. This can be achieved by improving the electrocatalyst for the anodic reaction.
In an effort to address these barriers, combinatorial sputtering, high-throughput screening, and traditional
methods were employed to investigate various thin film electrocatalyst combinations containing alternately
varying content of platinum (Pt), palladium (Pd) and aluminium (Al), towards the electro-oxidation of
aqueous SO2. Throughout the investigation the thin film electrocatalysts were exposed to different physical
and electrochemical treatments and characterisation techniques, resulting in new insights gained. Included
in the list of techniques and methods are combinatorial sputtering, photolithography, high-throughput
screening, cyclic voltammetry, linear polarisation, rapid thermal annealing treatment (RTA), energy
dispersive X-ray spectroscopy (EDX), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy
(XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The combinatorial sputtering approach, based on magnetron enhanced plasma sputtering and
photolithography, was developed and employed in the syntheses of the thin film electrocatalysts. A multichannel
potentiostat, connected to a custom manufactured multi-working electrode electrochemical cell,
allowed for high-throughput parallel screening of the deposited electrocatalysts towards the electrooxidation
of aqueous SO2. Employing onset potential and current output as the screening criteria together
with stability tests and the results obtained from physical characterisation (by employment of the above
mentioned techniques), thin films exhibiting satisfactory performance were identified. A Pt3Pd2 thin film,
annealed at 800 °C, and a ternary combination of Pt40Pd57Al3, annealed at 900 °C, were identified as
potential contenders to compete with pure Pt that is currently being employed as the anode material for
electrochemically catalysing the electro-oxidation of SO2. Both Pt3Pd2 and Pt40Pd57Al3 thin films contain
less Pt than a pure Pt thin film, while exhibiting increased electrocatalytic activity, and can serve as a basis
for future studiesNational Research Foundatio
Exploring acyl azides chemistry in continuous flow systems
No full textOrganic azides are important in the synthesis of many target molecules of great use in fine chemical and pharmaceutical production. The use of this class of compounds is however limited due to their hazardous nature and many safety concerns, as they are highly exothermic. Micro reactors can handle exotherms extremely well, due to the inherent high surface area to volume ratio, unlike the conventional batch process. This dissertation therefore aims to investigate the safe application of micro reactors in acyl azide chemistry.With this in mind, Chapter 1 provides a comprehensive background on organic azides, reaction calorimetric studies, flow chemistry technology (micro reactors) and their theoretical advantages. This chapter also discusses the preparation of organic azides in continuous flow systems and scaling up in continuous flow systems. Chapter 2 illustrates and discusses multivariate optimisation of benzoyl azide synthesis as a model reaction, synthesis of other acyl azides using the model reaction optimised conditions and multistep synthesis of carbamates, amides and amines in continuous flow systems via the Curtius rearrangement of benzoyl azide formed in situ from benzoyl chloride and sodium azide. The chapter also discusses process hazards analysis and evaluation of benzoyl azide synthesis and decomposition using calorimetric studies. It also investigates and discusses the effects of different mixing regimes and channel sizes on scale up. Chapter 3 has comprehensive experimental details for the whole dissertation with Chapter 4 providing the concluding remarks and future work recommendations.National Research Foundatio
NRF Alumni database
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 8th annual Research Administrators Workshop (RAW) from 9 to 11 October 2017 in the Western Cape. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management