204 resultados para Vitamin D


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Antioxidants in acute physical exercise and exercise training remain a hot topic in sport nutrition, exercise physiology and biology, in general (Jackson, 2008; Margaritis and Rousseau, 2008; Gomez-Cabrera et al., 2012; Nikolaidis et al., 2012). During the past few decades, antioxidants have received attention predominantly as a nutritional strategy for preventing or minimising detrimental effects of reactive oxygen and nitrogen species (RONS), which are generated during and after strenuous exercise (Jackson, 2008, 2009; Powers and Jackson, 2008). Antioxidant supplementation has become a common practice among athletes as a means to (theoretically) reduce oxidative stress, promote recovery and enhance performance (Peternelj and Coombes, 2011). However, until now, requirements of antioxidant micronutrients and antioxidant compounds for athletes training for and competing in different sport events, including marathon running, triathlon races or team sport events involving repeated sprinting, have not been determined sufficiently (Williams et al., 2006; Margaritis and Rousseau, 2008). Crucially, evidence has been emerging that higher dosages of antioxidants may not necessarily be beneficial in this context, but can also elicit detrimental effects by interfering with performance-enhancing (Gomez-Cabrera et al., 2008) and health-promoting training adaptations (Ristow et al., 2009). As originally postulated in a pioneering study on exercise-induced production of RONS by Davies et al. (1982) in the early 1980s, evidence has been increasing in recent years that RONS are not only damaging agents, but also act as signalling molecules for regulating muscle function (Reid, 2001; Jackson, 2008) and for initiating adaptive responses to exercise (Jackson, 2009; Powers et al., 2010). The recognition that antioxidants could, vice versa, interact with the signalling pathways underlying the responses to acute (and repeated) bouts of exercise has contributed important novel aspects to the continued discussion on antioxidant requirements for athletes. In view of the recent advances in this field, it is the aim of this report to examine the current knowledge of antioxidants, in particular of vitamins C and E, in the basic nutrition of athletes. While overviews on related topics including basic mechanisms of exercise-induced oxidative stress, redox biology, antioxidant defence systems and a summary of studies on antioxidant supplementation during exercise training are provided, this does not mean that this report is comprehensive. Several issues of the expanding and multidisciplinary field of antioxidants and exercise are covered elsewhere in this book and/or in the literature. Exemplarily, the reader is referred to reviews on oxidative stress (Konig et al., 2001; Vollaard et al., 2005; Knez et al., 2006; Powers and Jackson, 2008; Nikolaidis et al., 2012), redox-sensitive signalling and muscle function (Reid, 2001; Vollaard et al., 2005; Jackson, 2008; Ji, 2008; Powers and Jackson, 2008; Powers et al., 2010; Radak et al., 2013) and antioxidant supplementation (Williams et al., 2006; Peake et al., 2007; Peternelj and Coombes, 2011) in the context with exercise. Within the scope of the report, we rather aim to address the question regarding requirements of antioxidants, specifically vitamins C and E, during exercise training, draw conclusions and provide practical implications from the recent research.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In Uganda, a significant proportion of the population depends on the micronutrient poor East African highland banana as a food staple. Consequently, micronutrient deficiencies such as vitamin A deficiency are an important health concern in the country. To reach most vulnerable rural poor populations, staple crops can be biofortified with essential micronutrients though conventional breeding or genetic engineering. This thesis provided proof of concept that genetically modified East African highland bananas with enhanced provitamin A levels can be generated and fully characterised in Uganda. In addition, provitamin A levels present in popular banana varieties was documented.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Public Relations and Marketing for Archives: A How-to-do-it Manual, New York, Neal-Schuman Publishers with the Society of American Archivists, 2011. xiv + 273 pp. ISBN 978-1-5557-0733-0. US$80.00 Public Relations and Marketing for Archives – A How-To-Do-It Manual provides a brief, but broad overview of the key elements of marketing, public relations and stakeholder engagement for archives...

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recently, the debate around critical literacy has dissipated as literacy education agendas and attendant policies shift to embrace more hybrid approaches to the teaching of senior English. This paper reports on orientations towards critical literacy as expressed by four teachers of senior English who teach culturally and linguistically diverse learners. Teachers’ understandings of critical literacy are important given the emphasis on Critical and Creative Thinking as well as Literacy as General Capabilities underpinning the Australian Curriculum. Using critical discourse analysis and Janks' (2010) Synthesis Model of Critical Literacy, interview and classroom data from four teachers of English as an Additional Language or Dialect (EAL/D) learners in two high schools were analysed for the ways these teachers constructed critical literacy in their talk and practice. While all four teachers indicated significant commitment to critical literacy as an approach to English language teaching, their understandings varied. These ranged from providing access to powerful genres, to rationalist approaches to interrogating text, with less emphasis on multimodal design and drawing on learner diversity. This has significant implications for what kind of learning is being offered to EAL/D learners in the name of English teaching, for syllabus design, and for teacher professional development.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mutations of UDP-N-acetyl-alpha-D-galactosamine polypeptide N-acetyl galactosaminyl transferase 3 (GALNT3) result in familial tumoural calcinosis (FTC) and the hyperostosis-hyperphosphataemia syndrome (HHS), which are autosomal recessive disorders characterised by soft-tissue calcification and hyperphosphataemia. To facilitate in vivo studies of these heritable disorders of phosphate homeostasis, we embarked on establishing a mouse model by assessing progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU), and identified a mutant mouse, TCAL, with autosomal recessive inheritance of ectopic calcification, which involved multiple tissues, and hyperphosphataemia; the phenotype was designated TCAL and the locus, Tcal. TCAL males were infertile with loss of Sertoli cells and spermatozoa, and increased testicular apoptosis. Genetic mapping localized Tcal to chromosome 2 (62.64-71.11 Mb) which contained the Galnt3. DNA sequence analysis identified a Galnt3 missense mutation (Trp589Arg) in TCAL mice. Transient transfection of wild-type and mutant Galnt3-enhanced green fluorescent protein (EGFP) constructs in COS-7 cells revealed endoplasmic reticulum retention of the Trp589Arg mutant and Western blot analysis of kidney homogenates demonstrated defective glycosylation of Galnt3 in Tcal/Tcal mice. Tcal/Tcal mice had normal plasma calcium and parathyroid hormone concentrations; decreased alkaline phosphatase activity and intact Fgf23 concentrations; and elevation of circulating 1,25-dihydroxyvitamin D. Quantitative reverse transcriptase-PCR (qRT-PCR) revealed that Tcal/Tcal mice had increased expression of Galnt3 and Fgf23 in bone, but that renal expression of Klotho, 25-hydroxyvitamin D-1α-hydroxylase (Cyp27b1), and the sodium-phosphate co-transporters type-IIa and -IIc was similar to that in wild-type mice. Thus, TCAL mice have the phenotypic features of FTC and HHS, and provide a model for these disorders of phosphate metabolism. © 2012 Esapa et al.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Two new star-burst compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms (1a and 1b) were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. Both compounds exhibit strong 1π–π⁎ transitions in the UV region and intense 1π–π⁎/intramolecular charge transfer (1ICT) absorption bands in the UV–vis region. Introducing the carbazole end-capped phenylene ethynylene arm on the 1,3,5-triazine core causes a slight bathochromic shift and enhanced molar extinction coefficient of the 1π–π⁎/1ICT transition band. Both compounds are emissive in solution at room temperature and 77 K, which exhibit pronounced positive solvatochromic effect. The emitting state could be ascribed to 1ICT state in more polar solvent, and 1π–π⁎ state in low-polarity solvent. The high emission quantum yields (Φem=0.90~1.0) of 1a and 1b (in hexane and toluene) make them potential candidates as efficient light-emitting materials. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these compounds can be tuned by the carbazole end-capped phenylene ethynylene arm, which would also be useful for rational design of photofunctional materials.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Gac fruits were physically measured and stored under ambient conditions for up to 2 weeks to observe changes in carotenoid contents (lycopene and beta carotene) in its aril. Initial concentrations in the aril of lycopene were from 2.378 mg/g fresh weight (FW) to 3.728 mg/g FW and those of beta carotene were from 0.257 to 0.379 mg/g FW. Carotenoid concentrations in the aril remained stable after 1 week but sharply declined after 2 weeks of storage. Gac oil, pressed from gac aril, has similar concentrations of lycopene and beta carotene (2.436 and 2.592 mg/g, respectively). Oil was treated with 0.02% of butylated hydroxytoluene, or with a stream of nitrogen or untreated then stored in the dark for up to 15 or 19 weeks under different temperatures (5 °C, ambient, 45 and 60 °C). Lycopene and beta carotene in control gac oil degraded following the first-order kinetic model. The degradation rate of lycopene and beta carotene in the treated oil samples were lower than that in the control oil but the first-order kinetic was not always followed. However, both lycopene and beta carotene degraded quickly in gac oil with the first-order kinetic under high temperature conditions (45 and 60 °C) regardless of the treatments used. © 2009 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background and Purpose Stroke is a multifactorial disease that may be associated with aberrant DNA methylation profiles.We investigated epigenetic dysregulation for the MTHFR gene among ischaemic stroke patients. Methods Cases (n=297) and controls (n=110) were recruited after obtaining signed written informed consent, following a screening process against the inclusion/exclusion criteria. Serum vitamin metabolites (folate, vitamin B12 and homocysteine) were determined using immunoassays and methylation profiles for CpGs A and B in the MTHFR gene were determined using bisulfitepyrosequencing method. Results Methylation of MTHFR significantly increased the susceptibility risk for ischemic stroke. In particular, CpG A outperformed CpG B in mediating folate and vitamin B12 levels to increase ischemic stroke susceptibility risks by 4.73 fold. CpGs A and B were not associated with either serum homocysteine levels or ischemic stroke severity. Conclusion CpG A is a potential epigenetic marker in mediating serum folate and vitamin B12 to contribute to ischemic stroke.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Plasma polymerization was used to coat a melt electrospun polycaprolactone scaffold to improve cell attachment and organization. Plasma polymerization was performed using an amine containing monomer, allylamine, which then allowed for the subsequent immobilization of biomolecules i.e. heparin and fibroblast growth factor-2. The stability of the plasma polymerized amine-coating was demonstrated by X-ray photoelectron spectroscopy analysis and imaging time-of-flight secondary ion mass spectrometry revealed that a uniform plasma amine-coating was deposited throughout the scaffold. Based upon comparison with controls it was evident that the combination scaffold aided cell ingress and the formation of distinct fibroblast and keratinocyte layers.