• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 62
  • 31
  • 7
  • 4
  • 2
  • 1
  • Tagged with
  • 124
  • 40
  • 28
  • 25
  • 24
  • 18
  • 17
  • 16
  • 16
  • 15
  • 15
  • 14
  • 14
  • 14
  • 14
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of Dietary Micronutrient Supplementation on the Development of Emotionality and Anxiety in a Normal Rat Population

Naismith Thomass, Phoebe Loris Sophia January 2013 (has links)
There is a growing body of research into the effects of micronutrients on human mental health. There is evidence that multi-ingredient formulas are beneficial especially in relation to serious mental health disorders such as mood and anxiety disorders, attention-deficit hyperactivity disorder and obsessive-compulsive disorders. However there is almost no scientific research which looks at the effects of these formulas in an animal population. Therefore the aim of this study was to investigate the effects of a micronutrient formula, EMPowerplus, on anxiety behaviour in rats, and whether there is a relationship between dose and anxiolytic effect. In order to investigate this 40 male and 40 female rats received a diet consisting of either 0%, 1.25%, 2.5% or 5% EMP+ from when they were weaned (post natal day 30) until the end of testing 141 days later. Animals were tested in a Y maze, a light-dark emergence box and an open field at mid-adulthood (PND 136-138) and late adulthood (PND 186-188). Results found that animals receiving the 5% supplemented diet occupied the centre squares the most, occupied the corner squares the least and ambulated the most in the open field compared to the other experimental groups and control groups. No significant differences were found in the Y maze or Light-dark box. Animals were found to display more anxiety-like behaviour at time 2 than at time 1 regardless of receiving a supplemented diet or not. Overall a higher dose of EMP+ was associated with the greatest reduction in anxiety related behaviour. Due to the impact of the September 4th, 2010 Canterbury Earthquake caution should be taken when interpreting these results.
2

The effect of liming on the quantity-intensity relationships of zinc fractions in soils

Sandabe, Mohammed K. January 1988 (has links)
Literature was reviewed on zinc fractionation and factors affecting the availability of zinc to plants. An experiment was conducted to study the effect of liming on zinc fractions in soils. Liming decreased exchangeable zinc. However, no definite trend was observed in the other zinc fractions with increasing soil pH. An understanding of the distribution of zinc among various fractions in soils is important to understanding its soil chemistry. An experiment was further conducted to study the effect of liming and types of anion on the quantity-intensity relationships of zinc in soils. It was found that for all the soils, at the same level of added zinc, adsorption increased with increasing lime rates. Zinc adsorption isotherms with NO<SUB>3<SUP>-</SUB></SUP> and C1<SUP>-</SUP> as counter ions have smoother curves than with SO<SUB>4<SUP>2-</SUB></SUP> and H<SUB>2</SUB>PO<SUB>4<SUP>-</SUB></SUP>. The adsorption was highest with NO<SUB>3<SUP>-</SUB></SUP> and lowest with H<SUB>2</SUB>PO<SUB>4<SUP>-</SUB></SUP> as the background anion. Quantity and intensity factors influence the availability of nutrients in soils to plants. These factors describe what is referred to as the `labile pool'. Understanding of zinc labile pool is enhanced by radio isotope usage. Hence, an experiment was conducted to study the effect of liming on zinc labile pool as measured by the uptake of ryegrass utilizing the radioactive isotope of zinc. For both two harvests of perennial ryegrass there was a decrease in shoot zinc concentrtion and uptake with increasing lime rates. Higher zinc concentration was found in the soils with zinc-65 than without zinc-65. No definite trend was however observed in zinc labile pool with increasing lime rates. Several forms of zinc fertilizer are available for correcting zinc deficiency in soil. Variation in the ability of plants to absorb and utilize the different forms of zinc have been observed by many researchers. An experiment was conducted to study the effect of liming and types of complexing agent on the chemical composition of winter wheat grown on two soils of varying texture. The zinc forms differed significantly at the lime rate zero in relation to foliar zinc concentration. A decrease in shoot zinc concentration and uptake was observed with increasing lime rate. A similar trend was observed for one soil in relation to phosphorus concentration, except at the highest lime rate, where it remained fairly constant. There was however, an increase in shoot calcium concentration and uptake with increasing lime rate.
3

Micronutrient dilution associated with alcohol and added sugar intake in the THUSA population / Marita Serfontein.

Serfontein, Marita January 2008 (has links)
The micronutrient intake of the average South African is not optimal. National fortification of staple foods does not solve all micronutrient deficiencies. Furthermore, urbanisation causes a shift in food intake, increasing the availability of cheaper and more energy dense food and drinks that are often lacking in micronutrients. It is unclear whether the current literature provides sufficient evidence of nutrient dilution by the moderate consumption of alcohol and/or added sugar. The aim of the present study was to evaluate the dietary intakes of a population in nutrition transition and determine the effect of intake of alcohol and added sugars on intakes of micronutrients and food groups to provide information for the development of preventive strategies in public health. A number of countries, including South Africa, suggest limited alcohol and sugar intakes in the Food Based Dietary Guidelines but do not quantify this recommendation. Data from the "Transition and Health during Urbanisation in South Africa" survey (THUSA) were analysed for dietary intakes (as determined by a validated quantified food frequency questionnaire), age and body mass index (BMI). The THUSA study was conducted during 1996 and 1998 in the North West Province and included 1854 "apparently healthy". Respondents aged 15 years and older from 37 randomly selected sites from rural and urban areas. Alcohol intake (absolute intake and percentage of energy) was the highest for men living in middle class urban areas. With increased urbanisation, the type of beer shifted from sorghum based to commercial beer. Sixty-one percent of men and 25% of women reported that they consumed alcohol at the time of the survey. Eighteen percent of men and 11.7% of women consumed more than 30g and 15g alcohol per day, respectively (intakes which are regarded as moderate). Men and women consuming the most alcohol had significantly higher mean intakes of most macro and micronutrients. However, the intake of vitamin Bi2, B6, folate, vitamin E and vitamin C did not meet the recommended dietary intake (RDA) across all levels of alcohol intake. Although the total energy intake increased with increased alcohol intake, there was no significant difference between the mean BMI of men or women with different levels of intake. One third of the population consumed more than a 100g of added sugar daily. Intake of sugar was the highest in the farm dwellers but the intake of sweets, cakes, cookies and cold drinks was the highest in the urban areas. As sugar intake increased so did energy, carbohydrates and most micronutrients. However, the intake of vitamin B12, folate, vitamin C and calcium did not meet the RDA across all levels of sugar intake. BMI did not differ between respondents with the highest and lowest sugar intake and no association was found between BMI and sugar intake. The THUSA study was conducted before fortification of staple food became law in October 2003. Maize meal and wheat flour are nowadays fortified with certain vitamins and minerals which may alleviate some micronutrient deficiencies. For future research it is imperative to establish the reasons for low intake of certain micronutrients rather than to look at a single food item in the diets of the South African adult population. Proper education on the intake of cheaper food sources of micronutrients needs to be highlighted at all levels of the health sector. / Thesis (M.Sc. (Dietetics)--North-West University, Potchefstroom Campus, 2009.
4

Micronutrient dilution associated with alcohol and added sugar intake in the THUSA population / Marita Serfontein.

Serfontein, Marita January 2008 (has links)
The micronutrient intake of the average South African is not optimal. National fortification of staple foods does not solve all micronutrient deficiencies. Furthermore, urbanisation causes a shift in food intake, increasing the availability of cheaper and more energy dense food and drinks that are often lacking in micronutrients. It is unclear whether the current literature provides sufficient evidence of nutrient dilution by the moderate consumption of alcohol and/or added sugar. The aim of the present study was to evaluate the dietary intakes of a population in nutrition transition and determine the effect of intake of alcohol and added sugars on intakes of micronutrients and food groups to provide information for the development of preventive strategies in public health. A number of countries, including South Africa, suggest limited alcohol and sugar intakes in the Food Based Dietary Guidelines but do not quantify this recommendation. Data from the "Transition and Health during Urbanisation in South Africa" survey (THUSA) were analysed for dietary intakes (as determined by a validated quantified food frequency questionnaire), age and body mass index (BMI). The THUSA study was conducted during 1996 and 1998 in the North West Province and included 1854 "apparently healthy". Respondents aged 15 years and older from 37 randomly selected sites from rural and urban areas. Alcohol intake (absolute intake and percentage of energy) was the highest for men living in middle class urban areas. With increased urbanisation, the type of beer shifted from sorghum based to commercial beer. Sixty-one percent of men and 25% of women reported that they consumed alcohol at the time of the survey. Eighteen percent of men and 11.7% of women consumed more than 30g and 15g alcohol per day, respectively (intakes which are regarded as moderate). Men and women consuming the most alcohol had significantly higher mean intakes of most macro and micronutrients. However, the intake of vitamin Bi2, B6, folate, vitamin E and vitamin C did not meet the recommended dietary intake (RDA) across all levels of alcohol intake. Although the total energy intake increased with increased alcohol intake, there was no significant difference between the mean BMI of men or women with different levels of intake. One third of the population consumed more than a 100g of added sugar daily. Intake of sugar was the highest in the farm dwellers but the intake of sweets, cakes, cookies and cold drinks was the highest in the urban areas. As sugar intake increased so did energy, carbohydrates and most micronutrients. However, the intake of vitamin B12, folate, vitamin C and calcium did not meet the RDA across all levels of sugar intake. BMI did not differ between respondents with the highest and lowest sugar intake and no association was found between BMI and sugar intake. The THUSA study was conducted before fortification of staple food became law in October 2003. Maize meal and wheat flour are nowadays fortified with certain vitamins and minerals which may alleviate some micronutrient deficiencies. For future research it is imperative to establish the reasons for low intake of certain micronutrients rather than to look at a single food item in the diets of the South African adult population. Proper education on the intake of cheaper food sources of micronutrients needs to be highlighted at all levels of the health sector. / Thesis (M.Sc. (Dietetics)--North-West University, Potchefstroom Campus, 2009.
5

An analysis of micronutrient consumption of mothers using the Demographic and Health Surveys of the Dominican Republic

Prieur Keys, Genevieve N 08 January 2016 (has links)
BACKGROUND: Micronutrient deficiency (vitamin A, iron, and iodine) is highly prevalent in the Dominican Republic as indicated by food consumption patterns, which are not reflective of consumption of micronutrient dense foods. Previous studies (Neves, Ramalho, Padilha, & Saunders, 2014) have shown that nutrition education offered by prenatal providers has a positive impact on nutrition outcomes in mothers and children. Little research exists which examines the difference in micronutrient consumption among mothers in the Dominican Republic. The aim of this study was to determine differences in micronutrient rich food consumption of mothers in the Dominican Republic based on type of prenatal provider (General practitioner, Obstetrics/gynecology (OBGYN) or no Provider). METHODS: The 2007 Dominican Republic DHS dataset was employed for this study. Odds ratios from multivariate logistic regression analyses were used to determine association between sources of prenatal service and micronutrient food intake. Statistical adjustments were made for residence, wealth index, education, marital status, smoking age and number children ever had. RESULTS: Compared with mothers who did not utilize any of the prenatal services, mothers who sought care from General practitioners and OBGYN had increased odds of consuming vitamin A, iodine and iron micronutrient rich foods, adjusting for residence, wealth index, education, marital status, smoking age and mother’s total number of children. However, the associations were not statistically significant. Compared to mothers who did not use prenatal care, mothers who used the services of General practitioners and OB/GYNs had greater odds, (OR=1.09; 95% CI:0.85-1.41) and (OR=1.29; 95% CI:1.01-1.65) respectively, of consuming at least one micronutrient food. Compared to mothers who did not use prenatal care, mothers who used the services of General practitioners (OR=1.31; 95% CI:1.00-1.70) and OB/GYNs and (OR=1.36; 95% CI:1.05-1.75), had greater odds of consuming at least two micronutrient foods. The corresponding odds ratios for consuming all three micronutrients for mothers using the services of General practitioners and OBGYN were 1.48 (95% CI=0.80-2.74) and 1.51 (95% CI=0.84-2.74), respectively. Prenatal Care and Micronutrient Dense Foods 3 DISCUSSION: Improvements and access to programs providing nutrition education for prenatal care providers, and medical and nutrition assistance to poor mothers may help to increase micronutrient rich food consumption in the Dominican Republic. KEY WORDS: micronutrient, diet, maternal, Dominican Republic
6

Identification of factors governing cadmium and zinc bioavailability in polluted soils

Hamon, Rebecca January 1995 (has links)
No description available.
7

Evaluation of secondary and micronutrients for soybean and wheat production

Widmar, Aaron January 1900 (has links)
Master of Science / Department of Agronomy / Dorivar Ruiz Diaz / The application of micronutrients to increase yields has become more popular with increased commodity prices and higher yielding crops. Two studies were completed evaluating secondary and micronutrient for soybean (Glycine max [L.] Merr.) and wheat (Triticum aestivum).The objective of the first study was to evaluate the response of soybean, under a double crop system after wheat, to soil-and foliar-applied macro and micronutrients. Macronutrients (N, P, K) were applied at 22 kg ha[superscript]-[superscript]1, micronutrients (Fe, Mn, Zn) were soil applied at 11 kg ha[superscript]-[superscript]1and S was applied at 22 kg ha[superscript]-[superscript]1. Plant response parameters were evaluated including changes in nutrient concentration, and seed yield response. Tissue samples were collected at the respective R1 growth stage. Samples were analyzed for the nutrients applied with the fertilizer treatments. Soybean seed yield slightly responded to soil-applied S, Mn, and Zn. When micronutrients were foliar-applied, seed yield was significantly decreased. The second study evaluated the application of S and micronutrients to winter wheat. The objectives were to evaluate the wheat response to sulfur and micronutrient fertilization and evaluate soil testing and tissue analysis as diagnostic tools. Fertilizer treatments consisted of sulfur, iron, manganese, zinc, boron, copper. All of the micronutrients were sulfate-based products and the sulfur treatments were applied as gypsum. Fertilizer treatments were applied as topdress in early spring. Soil samples were collected before fertilizer application and after harvest. Flag leaf samples were collected and analyzed for the nutrients applied with the fertilizer treatments. Significant increases in tissue concentration were observed when Zn, B, and S were applied. Significant increases in soil test Zn, Cu, B, and S were observed compared to the control treatment. Despite the increases in soil test concentration across locations, no significant increases in yield by any of the nutrients or combination of nutrients were observed.
8

Micronutrient Treatment for Adolescents with Severe Mood Dysregulation: A Single-Case Reversal Design Analysis

Harrison, Rachel January 2011 (has links)
Research has examined the effects of micronutrients on mood in both healthy and psychiatric populations. EMPowerplus (EMP+) is a formula containing a wide range of vitamins and minerals. It has been examined for the treatment of mood instability, anxiety, Attention Deficit Hyperactivity Disorder (ADHD) and autism. The present study trialled EMP+ with five adolescents, aged 16-21, all with Severe Mood Dysregulation (SMD) as well as co-occuring psychiatric diagnoses i.e. ADHD, anxiety and substance abuse. The sample reflects a group of adolescents with complex psychiatric presentations and therefore difficult to treat. An ABAB (off-on-off-on) research design was employed. An open-label trial (8 weeks) of the micronutrients was followed by a withdrawal phase (8 weeks) and then a reinstatement of the micronutrients for a longer period of time (up to 24 weeks). There were in-depth pre and post assessments and on-going monitoring of the participants for the duration of the study. Clinically significant improvements in symptoms and functioning were demonstrated in three/four participants. Two participants demonstrated on-off control of psychiatric symptoms, with a reversal and replication of treatment effect. Further, one participant demonstrated clinically significant improvements in mood and functioning while on the micronutrients; however, he was lost to follow up following the 7.1 earthquake, and a reversal was not obtained. One participant demonstrated a trend toward improvements in mood while on the micronutrients and subsequent deterioration during the wash-out phase. However, she decided to withdraw from the study at four weeks off to go on psychiatric medication. Further, one participant demonstrated a variable response. This study provides some further evidence that micronutrients may be an effective treatment for psychiatric symptoms, consistent with other reports. Further research, such as randomised clinical trials and studies investigating the mechanisms of action, appears warranted.
9

Nutrition and Oxidative Parameters in Pregnancy, Size at Birth and Metabolic Status of the Offspring at 4.5 Years : The MINIMat Trial in Rural Bangladesh

Lindström, Emma January 2012 (has links)
Undernutrition and oxidative stress in fetal life and infancy may lead to adverse health outcomes in the offspring. We studied nutrition and oxidative parameters in pregnancy and their associations with birth anthropometry and metabolic status in the children. In Matlab in rural Bangladesh, women were randomized to either early (Early) invitation to food supplementation or to start at their own liking (Usual). Women were also allocated to either; 1) 60 mg iron and 400 µg folic acid (Fe60F), 2) multiple micronutrients including 30 mg iron and folic acid (MMS), or 3) 30 mg iron and folic acid (Fe30F). Micronutrients (hemoglobin, iron, zinc, folic acid, vitamin B-12) were assessed in pregnancy week 14, lipid peroxidation in week 14 and 30, and DNA oxidation in week 19. The offspring were assessed for anthropometric measurements at birth and metabolic status at 4.5 years. Micronutrient deficiencies were common with zinc and vitamin B-12 deficiency being most prevalent. Anemia was present in approximately one third of women, however, iron deficiency was uncommon seen in only 2%. Maternal Early food supplementation group resulted in an improved lipid status in the children at 4.5 years compared to Usual food group. Prenatal use of MMS lowered the children’s glucose, insulin, HOMA-IR, and growth factors compared to Fe60F.   Lipid peroxidation in early pregnancy was associated with size at birth and insulin and HOMA-IR levels in the children. Lipid peroxidation in late pregnancy, however, was associated with the children’s lipid status. Both increasing lipid peroxidation and increasing DNA oxidation was associated with decreasing IGF-1 levels.  The beneficial effects of an Early start of food supplementation show that an improved prenatal nutrition may have lasting effects in the offspring and highlights the importance of early timing food supplementation. Use of MMS, however, resulted in lower insulin levels, which, considering the already low level of insulin in these children, may be a cause of concern. MMS also resulted in growth factors indicative of slower growth and further research appears to be needed before scaling up the use of MMS. Oxidative parameters in pregnancy were associated with longer-term outcomes in the offspring, suggesting that oxidative stress may be involved in the development of later metabolic disease.
10

Effect of a micronutrient-fortified beverage on cognition and nutritional status of primary school children / C. Taljaard.

Taljaard, Christine January 2012 (has links)
Childhood micronutrient deficiencies have negative effects on cognition. Little is known about the effects of combined consumption of micronutrients and sugar on growth and cognitive function. The aim of this thesis was to 1) investigate the effects of micronutrients and sugar, alone and in combination, in a beverage, on growth and cognition in South African children and 2) review recent evidence on iron status and anaemia prevalence in South African children since the National Food Consumption Survey-Fortification Baseline-2005 (NFCS-FB-2005). Children (n = 408, 6−11 years) were randomly allocated to a beverage containing 1) micronutrients with sugar, 2) micronutrients with non-nutritive sweetener, 3) no micronutrients with sugar, or 4) no micronutrients with non-nutritive sweetener for 8.5 months. Cognition was assessed using sub-tests from the Kaufman Assessment Battery for Children-II. Growth was assessed as weight-for-age (WAZ), height-for-age and body-mass-index-for-age z-scores. Relevant internet search engines identified studies reporting iron status of South African children after 2005. Secondary analysis was conducted on NFCS-FB-2005 provincial data for children 7−9 years old. Positive intervention effects were observed for micronutrients (0.76; 95% CI: 0.10, 1.42) and sugar (0.71; 95% CI: 0.05, 1.37) on Atlantis (measure learning ability), and sugar on Rover (measure simultaneous processing) (0.72; 96% CI: 0.08, 1.35) test scores. Attenuating micronutrient x sugar interactions were observed on Atlantis, Number Recall (measure sequential processing) and Rover test performance. Micronutrients or sugar alone lowered WAZ. In combination, this effect was attenuated (significant micronutrient x sugar interaction). Four studies from four different provinces were identified. All reported lower anaemia prevalence than the NFCS-FB-2005 (KwaZulu-Natal (11.5% vs 14.4%), North West (6.9% vs 27%) Western Cape (17.2% vs 18.8%) and Northern Cape (5.4% vs 22.2%). A beverage fortified with micronutrients or added sugar had beneficial effects on cognition, but a lowering effect on WAZ in the children. Unexpectedly, the combination of micronutrients and sugar attenuated these effects. In the identified studies, anaemia prevalence in school-aged children was lower than reported in the NFCS-FB-2005. / Thesis (PhD (Nutrition))--North-West University, Potchefstroom Campus, 2013.

Page generated in 0.0676 seconds