62 resultados para Modification of the microflora


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Objective. To develop a version of the Melbourne Low-Vision ADL Index that measures the personal impact of disability in activities of daily living (ADL's). Also, to determine the relationship between clinical measures of vision impairment and disability impact.

Methods. The Melbourne Low-Vision ADL Index (MLVAI) is a desk-based clinical assessment of disability in ADL's. Ability to perform each item is rated on a five-level descriptive scale from zero to four. In this study, the original version of the MLVAI was modified to measure disability impact. The simple modification involved weighting each item by the importance of that item to the person being tested. Importance was also rated on a five-level scale from zero to four. The validity and reliability of the Weighted Melbourne Low-Vision ADL Index (MLVAIW) was determined for 97 vision-impaired subjects in a cross-sectional study.

Results. Cronbach's alpha coefficient indicated an internal reliability of 0.94, and an intraclass correlation coefficient indicated an overall reliability of 0.88. The standard error of measurement was 24.7 points (out of a possible score of 400). There was a statistically significant difference in test scores between normal subjects and vision-impaired subjects. All vision measures had a high, statistically significant correlation with MLVAIW score. Near-word acuity had the strongest correlation (rs = 0.78, p < 0.001), followed by Melbourne Edge Test contrast sensitivity (rs = -0.72, p < 0.001). Visual field had the weakest correlation (rs = -0.52, p < 0.001). The best predictive model of MLVAIW score incorporated the variables age, near-word acuity, and visual field. Together, these variables accounted for 65.1% of the variance in MLVAIW score.

Conclusions. The MLVAI is highly valid and reliable when weighted by a scale that reflects the personal importance of ADL's. The MLVAIW can provide information over and above that obtained with the usual clinical vision measures and may be used to assess low-vision patients and to measure low-vision rehabilitation outcomes. It is suggested that the assessment of disability using the original MLVAI and the assessment of the impact of disability using the MLVAIW should be kept separate to facilitate the clear interpretation of the outcomes of low-vision rehabilitation.

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The detrimental effects of UV radiation are having a significant impact on our life and environment. The development of effective UV shielding agents is therefore of great importance to our society. ZnO nanoparticles are considered to be one of the most effective UV blocking agents. However, the development of ZnO-based UV shielding products is currently hindered due to the adverse effects of the inherent photocatalytic activity exhibited by ZnO. This paper reports our recent study on the possibility of reducing the photoactivity of ZnO nanoparticles via surface modification and impurity doping. It was found that the photoactivity was drastically reduced by SiO2-coatings that were applied to ZnO quantum dots using the Stöber method and a microemulsion technique. The effect of transition metal doping on the photoactivity was also studied using mechanochemical processing and a co-precipitation method. Cobalt doping reduced the photoactivity, while manganese doping led to mixed results, possibly due to the difference in the location of dopant ions derived from the difference in the synthesis methods.

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A facile, two-step method for chemically attaching single-stranded DNA to graphitic surfaces, represented here by carbon nanotubes, is reported. In the first step, an azide-containing compound, N-5-azido-nitrobenzoyloxy succinimide (ANB-NOS), is used to form photo-adducts on the graphitic surfaces in a solid-state photochemical reaction, resulting in active ester groups being oriented for the subsequent reactions. In the second step, pre-synthesized DNA strands bearing a terminal amine group are coupled in an aqueous solution with the active esters on the photo-adducts. The versatility of the method is demonstrated by attaching pre-synthesized DNA to surfaces of carbon nanotubes in two platforms—as vertically-aligned multi-walled carbon nanotubes on a solid support and as tangled single-walled carbon nanotubes in mats. The reaction products at various stages were characterized by x-ray photoelectron spectroscopy. Two different assays were used to check that the DNA strands attached to the carbon nanotubes were able to bind their partner strands with complementary base sequences. The first assay, using partner DNA strands tethered to gold nanoparticles, enabled the sites of DNA attachment to the carbon nanotubes to be identified in TEM images. The second assay, using radioactively labelled partner DNA strands, quantified the density of functional DNA strands attached to the carbon nanotubes. The diversity of potential applications for these DNA-modified carbon-nanotube platforms is exemplified here by the successful use of a DNA-modified single-walled carbon-nanotube mat as an electrode for the specific detection of metal ions.

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The intergallery expansion development of a series of differently modified montmorillonite polystyrene nanocomposites was directly observed with time-resolved in situ small-angle X-ray scattering (SAXS) using synchrotron radiation. The results indicated that the interlayer expansion varied depending on the clay modification and the chemical compatibility of the clay modifiers with the styrene monomer. The influence of the differently modified clays on the free radical polymerization was also investigated, particularly the effect on the conversion of styrene and molecular weight evolution of the polymer. On the basis of the kinetic study of the polymerization of styrene in the presence of varied modified clay particles, the intergallery expansion mechanism was postulated and discussed for different composite morphologies. Such studies provide an important guideline for the design of clay modifiers and development of clay–polymer nanocomposites.

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This review addresses how the ecosystem approach to aquaculture (EAA) can optimize aquaculture-fisheries interactions considering different spatial scales from farm, aquaculture zone and watershed through to the global market. Aquaculture and fisheries are closely related subsectors with frequent interactions, largely due to the sharing of common ecosystems and natural resources. Interactions are also born from the flow of biomass from fisheries to aquaculture through fish-based feeds (e.g. fishmeal, fish oil and trashfish), through the collection of wild seed and brookstock, and genetic resources and biomass transfer from aquaculture to fisheries through culture-based fisheries (CBF) and escapees. Negative effects include modification of habitats affecting fisheries resources and activities (e.g. mangrove clearing for shrimp ponds, seabed disturbances through anchoring of aquaculture cages or pens, damage to seagrasses, alteration to reproductive habitats, biodiversity loss). Eutrophication of waterbodies due to excess nutrient release leading to anoxia and fish mortality can also impact negatively on biodiversity and wild fish stocks. Release of diseases and chemicals also imposes some threats on fisheries. Yet there could be beneficial impacts; for example, aquaculture is increasingly contributing to capture fisheries through CBF and could contribute to restore overfished stocks. Aquaculture can offer alternative livelihoods to fisherfolk, providing increased opportunity to them and also to their families, and especially to women. Aquaculture-increased production and marketing can also enhance and indirectly improve processing and market access to similar fishery products. The ecosystem approach to aquaculture (EAA) is a strategy for the management of the sector that emphasizes intersectoral complementarities by taking into account the interactions between all the activities within ecologically meaningful boundaries and acknowledging the multiple services provided by ecosystems. The main objective of this review is to understand the status of aquaculture-fisheries interactions associated with the biological, technological, social, economic, environmental, policy, legal and other aspects of aquaculture development and to analyze how these interactions are or could be addressed with an EAA. Therefore, the review involves aspects of scoping, identification of issues, prioritizing, devising management tools and plans for minimizing negative effects and optimizing positive ones within the context of social-ecological resilience, at different relevant geographical scales. Many of the management measures suggested in this review must involve not only EAA but also an ecosystem approach to fisheries (EAF), especially to deal with issues such as fishery of wild seed and the management of fisheries to produce fishmeal/oil for pelleted feeds or for direct feeding with wet fish. The implementation of EAA and EAF should help to overcome the sectoral and intergovernmental fragmentation of resource management efforts and assist in the development of institutional mechanisms and private-sector arrangements for effective coordination among various sectors active in ecosystems in which aquaculture and fisheries operate and between the various levels of government. Ecosystem-based management involves a transition from traditional sectoral planning and decision-making to the application of a more holistic approach to integrated natural resource management in an adaptive manner.

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Background

Available data suggest that body dissatisfaction is common during pregnancy and may even be a precursor to post-natal depression. However, in order to accurately identify at-risk women, it is essential to first establish that body image measures function appropriately in pregnant populations. Our study examines the suitability of the Body Attitudes Questionnaire (BAQ) for measuring body dissatisfaction among pregnant women by comparing the psychometric functioning of the BAQ: (1) across key phases of pregnancy, and (2) between pregnant and non-pregnant women. 

Methods:
A total of 176 pregnant women from Melbourne, Victoria filled out a questionnaire battery containing demographic questions and the Body Attitudes Questionnaire at 16, 24, and 32 weeks during pregnancy. A comparison group of 148 non-pregnant women also completed the questionnaire battery at Time 1. Evaluations of the psychometric properties of the BAQ consisted of a series of measurement invariance tests conducted within a structural equation modelling framework.

Results:
Although the internal consistency and factorial validity of the subscales of the BAQ were established across time and also in comparisons between pregnant and non- pregnant women, measurement invariance tests showed non-invariant item intercepts across pregnancy and also in comparison with the non-pregnant subgroup. Inspection of modification indices revealed a complex, non-uniform pattern of differences in item intercepts across groups.

Conclusions:
Collectively, our findings suggest that comparisons of body dissatisfaction between pregnant and non-pregnant women (at least based on the BAQ) are likely to be conflated by differential measurement biases that serve to undermine attempts to accurately assess level of body dissatisfaction. Researchers should be cautious in assessments of body dissatisfaction among pregnant women until a suitable measure has been established for use in this population. Given the fact that body dissatisfaction is often associated with maladaptive behaviours, such as unhealthy eating and extreme weight loss behaviours, and with ante-and post-natal depression, that have serious negative implications for women’s health and well-being, and potentially also for the unborn foetus during pregnancy, developing a suitable body image screening tool, specific to the perinatal period is clearly warranted.

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Nanofibrous materials yielded by the self-assembly of peptides are rich in potential; particularly for the formation of scaffolds that mimic the landscape of the host environment of the cell. Here, we report a novel methodology to direct the formation of supramolecular structures presenting desirable amino acid sequences by the self-assembly of minimalist peptides which cannot otherwise yield the desired scaffold structures under biologically relevant conditions. Through the rational modification of the pK?, we were able to optimise ordered charge neutralised assembly towards in vivo conditions.

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Boron nitride nanotubes were functionalized with microperoxidase-11 in aqueous media, showing improved catalytic performance due to a strong electron coupling between the active centre of microperoxidase-11 and boron nitride nanotubes.

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μ-Conotoxin μ-KIIIA, from Conus kinoshitai, blocks mammalian neuronal voltage-gated sodium channels (VGSCs) and is a potent analgesic following systemic administration in mice. We have determined its solution structure using NMR spectroscopy. Key residues identified previously as being important for activity against VGSCs (Lys7, Trp8, Arg10, Asp11, His12, and Arg14) all reside on an α-helix with the exception of Arg14. To further probe structure−activity relationships of this toxin against VGSC subtypes, we have characterized the analogue μ-KIIIA[C1A,C9A], in which the Cys residues involved in one of the three disulfides in μ-KIIIA were replaced with Ala. Its structure is quite similar to that of μ-KIIIA, indicating that the Cys1−Cys9 disulfide bond could be removed without any significant distortion of the α-helix bearing the key residues. Consistent with this, μ-KIIIA[C1A,C9A] retained activity against VGSCs, with its rank order of potency being essentially the same as that of μ-KIIIA, namely, NaV1.2 > NaV1.4 > NaV1.7 ≥ NaV1.1 > NaV1.3 > NaV1.5. Kinetics of block were obtained for NaV1.2, NaV1.4, and NaV1.7, and in each case, both kon and koff values of μ-KIIIA[C1A,C9A] were larger than those of μ-KIIIA. Our results show that the key residues for VGSC binding lie mostly on an α-helix and that the first disulfide bond can be removed without significantly affecting the structure of this helix, although the modification accelerates the on and off rates of the peptide against all tested VGSC subtypes. These findings lay the groundwork for the design of minimized peptides and helical mimetics as novel analgesics.

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A key requirement of modern steels – the combination of high strength and high deformability – can best be achieved by enabling a local adaptation of the microstructure during deformation. A local hardening is most efficiently obtained by a modification of the stacking sequence of atomic layers, resulting in the formation of twins or martensite. Combining ab initio calculations with in situ transmission electron microscopy, we show that the ability of a material to incorporate such stacking faults depends on its overall chemical composition and, importantly, the local composition near the defect, which is controlled by nanodiffusion. Specifically, the role of carbon for the stacking fault energy in high-Mn steels is investigated. Consequences for the long-term mechanical properties and the characterisation of these materials are discussed.

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Amino-functionalized MIL-53(Al) was synthesized, activated, and modified in a postsynthetic modification step using formic acid. All reaction products were characterized in detail. Solid-state NMR spectroscopy unequivocally demonstrates the presence of the different guest species as well as the successful post-synthetic functionalization.

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Previous school obesity-prevention reviews have included multi-component interventions. Here, we aimed to review the evidence for the effect of isolated food environment interventions on both eating behaviours (including food purchasing) and/or body weight. Five electronic databases were searched (last updated 30 November 2013). Of the 1,002 unique papers identified, 55 reported on school food environment changes, based on a review of titles and abstracts. Thirty-seven further papers were excluded, for not meeting the inclusion criteria. The final selection consisted of 18 papers (14 United States, 4 United Kingdom). Two studies had a body mass index (BMI) outcome, 14 assessed purchasing or eating behaviours and two studies assessed both weight and behaviour. Seventeen of 18 papers reported a positive outcome on either BMI (or change in BMI) or the healthfulness of food sold or consumed. Two studies were rated as strong quality and 11 as weak. Only three studies included a control group. A school environment supportive of healthy eating is essential to combat heavy marketing of unhealthy food. Modification of the school food environment (including high-level policy changes at state or national level) can have a positive impact on eating behaviours. A need exists, however, for further high-quality studies.

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Titanium and its alloys are excellent candidates for biomedical implant. However, they exhibit relatively poor tribological properties. In this study, a two-step treatment including surface mechanical attrition treatment (SMAT) combined with thermal oxidation process has been developed to improve the tribological properties and biocompatibility of Ti. Ti after two-step treatment shows excellent wear-resistance and biocompatibility among all Ti samples, which can be ascribed to the highest surface energy, well crystallinity of rutile layer on its surface. Overall, the two-step treatment is a prospective method to produce excellent biomedical Ti materials.

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In this research, strontium (Sr) and surface modification were used to improve the
biocompatibility of titanium (Ti) based implant materials.