82 resultados para fibers and carotenoids


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Objective To investigate the relationship between basal cell carcinoma (BCC) and antioxidant nutrients, specifically carotenoids, vitamin E and selenium.

Methods The Nambour Skin Cancer Study is an ongoing, community-based study of randomly selected adult residents of a township in sub-tropical Queensland, Australia. Using a nested case–control design, incident cases of BCC (n=90) were compared with age and sex matched controls (n=90). Dietary exposure was measured using food frequency questionnaire estimates of intake as well as serum biomarkers. Other determinants of skin cancer including sun exposure were also considered. Dietary intakes were adjusted for energy intake, and serum carotenoids and vitamin E were adjusted for serum cholesterol. Odds ratios were calculated across quartiles of dietary intake and serum biomarkers and linear trends were assessed using logistic regression, adjusting for age, sex and supplement use.

Results and conclusions In this prospective study no significant associations were found between BCC and carotenoids, vitamin E or selenium, as measured by serum biomarkers or dietary intake, although there was a suggestion of a positive association with lutein intake.

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The felting propensity of different animal fibers, particularly alpaca and wool, has been examined. The Aachen felting test method was employed. 1 g of each type of fiber was soaked in 50 ml of wetting solution and agitated in a dyeing machine to make felt balls. The diameter of each ball was measured in nine directions and the ball density was calculated in g/cm3; the higher the density value of the ball, the higher the feltability of the fibers. The effects of fiber diameter and fiber length on the felting propensity of these fibers were investigated. The results show that the alpaca fibers felt to a higher degree than wool fibers, and short and fine cashmere fibers have lower felting propensity than wool fibers at a similar diameter range. There is a higher tendency of felting for bleached and dyed alpaca fibers than for untreated fibers. Fiber length has a remarkable influence on the propensity of fiber felting. Cotton and nylon fibers were also tested for felting propensity to verify the mechanism responsible for the different fiber felting behavior.

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Uncoupling protein 3 (UCP3) is a muscle mitochondrial protein believed to uncouple the respiratory chain, producing heat and reducing aerobic ATP production. Our aim was to quantify and compare the UCP3 protein levels in type I, IIa and IIx skeletal muscle fibers of endurance-trained (Tr) and healthy untrained (UTr) individuals. UCP3 protein content was quantified using Western blot and immunofluorescence. Skeletal muscle fiber type was determined by both an enzymatic ATPase stain and immunofluorescence. UCP3 protein expression measured in skeletal muscle biopsies was 46% lower ( P=0.01) in the Tr compared to the UTr group. UCP3 protein expression in the different muscle fibers was expressed as follows; IIx>IIa>I in the fibers for both groups ( P<0.0167) but was lower in all fiber types of the Tr when compared to the UTr subjects ( P<0.001). Our results show that training status did not change the skeletal muscle fiber hierarchical UCP3 protein expression in the different fiber types. However, it affected UCP3 content more in type I and type IIa than in the type IIx muscle fibers. We suggest that this decrease may be in relation to the relative improvement in the antioxidant defense systems of the skeletal muscle fibers and that it might, as a consequence, participate in the training induced improvement in mechanical efficiency.

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Image processing and pattern recognition have been successfully applied in many textile related areas. For example, they have been used in defect detection of cotton fibers and various fabrics. In this work, the application of image processing into animal fiber classification is discussed. Integrated into / with artificial neural networks, the image processing technique has provided a useful tool to solve complex problems in textile technology. Three different approaches are used in this work forfiber classification and pattern recognition: feature extraction with image process, pattern recognition and classification with artificial neural networks, and feature recognition and classification with artificial neural network. All of them yieldssatisfactory results by giving a high level of accuracy in classification.

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Fiber irregularity affects fiber mechanical properties. This study has, for the first time, introduced the concept of limiting irregularity to single wool fibers. The limiting irregularity is the minimum variation in fiber cross sectional area that can be expected of a single wool fiber, assuming a random length-wise distribution of its constituent cortical cells. Cortical cells were extracted from merino wool fibers and their dimensions were measured from SEM images to calculate their cross sectional area variations both between cortical cells and within cortical cells, and to work out the average number of cortical cells in the cross section of wool fibers of a given diameter. Single wool fibers were also measured at 5 µm interval along length for fiber diameter variations. These variations were found to be larger than that based on fiber limiting irregularity.

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This paper presents the use of the wavelet transform to extract fiber surface texture features for classifying cashmere and superfine merino wool fibers. Extracting features from brightness variations caused by the cuticular scale height, shape and interval provides an effective way for characterizing different animal fibers and subsequently classifying them. This may enable the development of a completely automated and objective system for animal fiber identification.

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Regular exercise, particularly progressive resistance training (PRT), is recognized as one of the most effective strategies to prevent age-related muscle loss (sarcopenia), but its effects on muscle function are mixed. However, emerging data indicates that high velocity PRT (fast concentric muscle contractions) is more effective for improving functional outcomes than traditional PRT. In terms of falls prevention, high-challenging balance training programs appear to be most effective. There is also compelling evidence that supplemental vitamin D is an effective therapeutic option for falls prevention. The findings from a recent meta-analysis revealed that supplemental vitamin D at a dose of at least 700–1,000 IU/d or an achieved serum 25(OH)D level of at least 60 nmol/L was associated with reduced falls risk among older individuals. Based on these findings, it is possible that the combination of exercise and vitamin D could have a synergistic effect on muscle morphology and function, particularly since both interventions have been shown to have beneficial effects on type II “fast twitch” muscle fibers and systemic inflammation, which have both been linked to losses in muscle mass and function. Unfortunately however, the findings from the limited number of factorial 2 × 2 design RCTs indicate that additional vitamin D does not enhance the effects of exercise on measures of muscle morphology, function or falls risk. However, none of these trials were adequately powered to detect a “synergistic” effect between the two treatment strategies, but it is likely that if an exercise-by-vitamin D interaction does exist, it may be limited to situations when vitamin D deficiency/insufficiency is corrected. Further targeted research in “high risk” groups is still needed to address this question, and evaluate whether there is a threshold level of serum 25(OH)D to maximize the effects of exercise on muscle and falls risk.

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The present investigation is on the microstructure evolution and hardness of powder metallurgically processed Al- 0.5 wt.%Mg base 10 wt.% short steel fiber reinforced composites. The 0.38 wt.% C short steel fibers of average diameter 50µm and 500-800µm length were nitrided and chromized in a fluid bed furnace. Nitriding was carried out at 525°C for 90, 30 and 5 min durations. Chromizing was performed at 950°C for 53 and 7 min durations, using thermal reactive deposition (TRD) and diffusion technique. The treated fibers and resulting reaction interfaces were characterized using metallographic, microhardness and XRD techniques.

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The transition from fetal to postnatal life involves clearance of liquid from the lung and airways, and rapid formation of a functional residual capacity. Despite the importance of the diaphragm in this process, the impact of birth on the mechanical and functional activity of its muscle fibers is not known. This study determined the contractile characteristics of individual “skinned” diaphragm fibers from 70 days (0.47) gestation to after birth in sheep. Based on differential sensitivity to the divalent ions calcium (Ca2+) and strontium (Sr2+), all fibers in the fetal diaphragm were classified as “fast,” whereas fibers from the adult sheep diaphragm exhibited a “hybrid” phenotype where both “fast” and “slow” characteristics were present within each single fiber. Transition to the hybrid phenotype occurred at birth, was evident after only 40 min of spontaneous breathing, and could be induced by simple mechanical stretch of diaphragm fibers from near-term fetuses (∼147 days gestation). Both physical stretch of isolated fibers, and mechanical ventilation of the fetal diaphragm in situ, significantly increased sensitivity to Ca2+ and Sr2+, maximum force generating capacity, and decreased passive tension in near-term and preterm fetuses; however, only fibers from near-term fetuses showed a complete transition to a “hybrid” activation profile. These findings suggest that stretch associated with the transition from a liquid to air-filled lung at birth induces physical changes of proteins determining the activation and elastic properties of the diaphragm. These changes may allow the diaphragm to meet the increased mechanical demands of breathing immediately after birth.

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This paper investigates the preparation and electrospinning of acidified-oxidized potato starch. In this article, acidified-oxidized potato starch was prepared by adding ammonium persulfate as an oxidizing agent and hydrochloric acid as a catalyst. The effect of reaction time, temperature, the concentration of hydrochloric acid and the content of ammonium persulfate on the viscosity and content of carboxyl were discussed. The optimum reaction conditions were as follows: 1.5 hours ,50℃, 0.5mol/l HCl, 2.5% (NH4)2S2O8. And then, the acidified-oxidized potato starch prepared at the optimum condition was dissolved in dimethyl sulfoxide (DMSO) to be electrospinned by contrast to native starch. Electrospinning of 5wt%-21wt% of modified starch in DMSO produced beads, beaded fibers, and smooth fibers, depending on the concentration range. Smooth fibers were observed until the concentration reached 19wt%, while native starch was 5wt%.

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Poly(styrene-β-isobutylene-β-styrene)-poly(3-hexylthiophene) (SIBS-P3HT) conducting composite fibers are successfully produced using a continuous flow approach. Composite fibers are stiffer than SIBS fibers and able to withstand strains of up 975% before breaking. These composite fibers exhibit interesting reversible mechanical and electrical characteristics, which are applied to demonstrate their strain gauging capabilities. This will facilitate their potential applications in strain sensing or elastic electrodes. Here, the fabrication and characterization of highly stretchable electrically conducting SIBS-P3HT fibers using a solvent/non-solvent wet-spinning technique is reported. This fabrication method combines the processability of conducting SIBS-P3HT blends with wet-spinning, resulting in fibers that could be easily spun up to several meters long. The resulting composite fiber materials exhibit an increased stiffness (higher Young’s modulus) but lower ductility compared to SIBS fibers. The fibers’ reversible mechanical and electrical characteristics are applied to demonstrate their strain gauging capabilities.

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Biopolymer-single walled carbon nanotube (SWNT)-biopolymer fibers were prepared using a continuous flow spinning approach. Polyelectrolyte complexation was facilitated by injecting a SWNT-biopolymer dispersion into a coagulation bath containing a biopolymer of opposite charge. We showed that the ability to spin fibers and their properties depend on processing conditions such as polyelectrolyte pH, sonolysis regime (conditions employed to disperse SWNT) and the order of adding the anionic and cationic biopolymer solutions. Maximizing the ionic nature through changes in the pH increased spin-ability, while combining a sonicated dispersion with an as-prepared (non-sonicated) polyelectrolyte solution allowed us to optimize sonolysis conditions while retaining spin-ability of fibers with smooth surface morphology. Addition of the cationic biopolymer-SWNT dispersion to the anionic biopolymer solution resulted in mechanical reinforcement with the increase in SWNT loading fraction. All fibers decreased their electrical resistance upon exposure to water vapor.

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A magnetic resin based on cardanol, furfural, and curaua fibers was prepared and characterized. The material could be used in oil-spill cleanup processes, because of its aromatic/aliphatic balance. The resin was prepared through bulk polycondensation of cardanol and furfural in the presence of curaua fibers and maghemite nanoparticles. Hydrophobicity of the curaua fibers was improved by acetylation, increasing the oil-absorbing capability of the composites. The obtained magnetic composites were studied by Fourier-transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Degree of cure, magnetic force, and oil-removal capability tests were also performed. The results show that the composites possess an elevated cure degree in addition to a considerable magnetic force. The materials exhibit a good oil removal capability in the presence of a magnetic field, which is improved by the use of acetylated curaua. In the best case, the composite filled with maghemite and curaua can remove 12 parts of oil from water.

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Thin films of molecular gels formed in a confined space have potential applications in transdermal delivery, artificial skin, molecular electronics, etc. The microstructures and properties of thin gel films can be significantly different from those of their bulk counterparts. However, so far a comprehensive understanding of the effects of spatial confinement on the molecular gelation kinetics, fiber network structure and related mechanical properties is still lacking. In this work, using rheological techniques, we investigated the effect of one-dimensional confinement on the formation kinetics of fiber networks in the molecular gelation process. Fractal analyses of the kinetic information in terms of an extended Dickinson model enabled us to describe quantitatively the distinct kinetic signature of molecular gelation. The structural features derived from gelation kinetics support well the fractal patterns of the fiber networks acquired by optical and electron microscopy. With the kinetics-structure correlation, we can gain an in-depth understanding of the confinement-induced differences in the structure and consequently the mechanical properties of a model molecular gelling system. Particularly, the confinement induced structural transition, from a three-dimensional, dense and compact spherulitic network composed of highly branched fibers to a quasi-two-dimensional sparse spherulitic network composed of less branched fibers and entangled fibrils at the boundary areas, renders a gel film to become less stiff but more ductile. Our study suggests here a new strategy of engineering the fiber network microstructure to achieve functional gel films with unusual but useful properties.

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 The objective of the thesis was to understand and develop the process of fermentation in marine microorganisms for the production of omega-3 fatty acids and carotenoids. Among marine microorganisms, thraustochytrids that belong to phytoplankton group was identified as sources of omega-3 fatty acids and other valuable co-products. In this research, more efficient and cost-effective production of omega-3 oils and other value added products was discussed by addressing the below key objectives. Fermentation strategy using lower cost raw materials, particularly carbon. Screening for new strains that can naturally produce high levels of PUFAs together with useful co-products that can be harvested along with the omega-3 oil.