ORCID Profile
0000-0003-4071-1213
Current Organisation
Deakin University
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Publisher: Wiley
Date: 27-04-2009
DOI: 10.1002/APP.30309
Publisher: Wiley
Date: 19-08-2016
DOI: 10.1002/APP.44273
Publisher: SAGE Publications
Date: 24-03-2015
Abstract: In this study, a model was set up for simulating the effects of varying fiber cross-sectional shapes on ultraviolet protection of fibers. The fiber diameter and fiber type were also involved in the model setting. Experiments of diffuse reflectance spectra measurement on natural (wool, cotton, silk), regenerated (bamboo viscose) and synthetic (polyester, nylon) fibers were conducted to verify the model predicted results. When a more complex shape was assumed as the fiber cross-section for model calculation, the predicted results have a better agreement with the actual results. The effects on ultraviolet absorption from fibers with different cross-sectional shapes were investigated at a single fiber, fiber bundle and yarn levels. With the same material, when the fiber cross-sectional area and the areal coverage of a single fiber were constant, the triangular shape had the lowest ultraviolet transmittance and the highest ultraviolet reflectance for a single fiber and also for a fiber bundle. The difference of fiber cross-sectional shapes was also significant in the ultraviolet protection of a single yarn.
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 03-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 1988
DOI: 10.1039/DT9880002759
Publisher: Wiley
Date: 07-1996
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/AN11235
Abstract: Genetic parameters (heritability, phenotypic and genetic correlations) were estimated for sulfur (S), calcium (Ca), magnesium (Mg), manganese (Mn) and trace metal content (i.e. Cu, copper Fe, iron Zn, zinc) of yearling (11 months, n = 387) and adult (23 months, n = 274) fleeces from the 2007 and 2008 cohorts of Merino progeny (including both ewes and wethers) born into the Sheep CRC Information Nucleus. There was significant genetic variation in S and all metals. Ninety percent of the variation in S and Zn content of yearling wool was genetic, while heritability estimates for the remaining metals were all higher than 0.28 except for Cu (h2 = 0.17 ± 0.11) and Mn (h2 = 0.03 ± 0.12) in yearling fleeces and Cu (h2 = 0.14 ± 0.18) in adult fleeces. Ca and Mg were very highly correlated both phenotypically (0.95 ± 0.01 as yearlings and adults) and genetically (0.95 ± 0.07 as yearlings). There were also strong genetic correlations between yearling and adult Ca and adult Mn (0.85 ± 0.22 and 0.88 ± 0.10), Mg and Mn (0.92 ± 0.10) and between yearling S and adult Zn (0.67 ± 0.22) and adult S and adult Zn (0.60 ± 0.22) suggesting similar genetic mechanisms controlling the biochemical pathways of incorporation of each pair of elements into the fibre. There were significant phenotypic correlations between certain elements and the brightness, yellowness and photostability of wool. Taken together across the yearling and adult measurements, the phenotypic and genetic correlations suggest that wool with higher concentrations of Ca and Mg would tend to be less bright, yellower and less photostable than wool with lower concentrations of these metals. Wool with higher concentrations of Mn would tend to have a similar impact to Ca and Mg on brightness, clean colour and photostability. Fe was also associated with less bright wool, however wool with a high Fe content would tend to be whiter but with a propensity to yellow following UVB exposure.
Publisher: Wiley
Date: 02-2006
Publisher: Wiley
Date: 11-03-2020
DOI: 10.1111/ICS.12601
Abstract: To study the effects of addition of a redox metal, copper, antioxidants and metal chelators on the formation of free radicals in natural white Caucasian hair subsequently exposed to UV light. Three different methods, electron paramagnetic resonance (EPR), a fluorescent probe for hydroxyl radical formation (terephthalate) and free radical photoyellowing, were used. These methods utilized different UV sources and reaction conditions, and so can give insights into the different mechanisms of action occurring during UV oxidation of hair. In addition, this study demonstrates how antioxidants and chelators can be screened to determine whether they can protect hair from UV damage. The three methods gave somewhat different results, illustrating the importance of reaction conditions and wavelength on the photochemical mechanisms, and the efficacy of additives to influence these reactions. EPR results showed that N-acetylcysteine (NAC) pre-treatment eliminated the intensity of the signal because of sulphur and carbon free radicals in white hair both before and after exposure to UVB radiation. Doping the hair with copper ions had no effect on the intensity of the EPR signal under dry conditions. Terephthalate fluorescent probe data showed that under wet conditions, irradiation of white hair with UVA produced significant amounts of hydroxyl radicals. Pre-treatment of hair with NAC reduced the number of •OH radicals produced by natural white hair compared to an untreated control. In contrast to the EPR result, white hair doped with copper ions produced significantly higher levels of •OH radicals under wet conditions. It appears that the ability of copper ions to catalyse the photogeneration free radicals in hair is highly dependent on water content. Photoyellowing data showed a benefit for oxalic acid but no difference for NAC and an increase in yellowing for EDTA. The micro-EPR and terephthalate fluorescent probe methods are both effective techniques to study production of free radicals by hair exposed to UV light under wet and dry conditions, respectively. Both assays are simple methods for determining the effectiveness of potential protective hair treatments against UV damage, but because they assess free radical damage under dry vs wet conditions, the chemistry created on UV exposure is different. This gives insights into mechanism of action, but results may not be consistent between the two methods for actives added for reduction of UV damage. NAC pre-treatment did reduce free radical generation in UV-exposed hair under both wet and dry conditions. Photoyellowing data are more complicated as it is a less direct measure of UV damage and is highly dependent on irradiation source. Using UVB irradiation is experimentally convenient but may not be appropriate, because UVB wavelengths comprise only 0.3% of terrestrial sunlight. The photochemistry of hair exposed to sunlight involves concurrent photobleaching and photoyellowing processes and is far more complex. Under UVB irradiation conditions, oxalic acid showed a yellowing benefit.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Wiley
Date: 09-1988
Publisher: Elsevier BV
Date: 11-1996
Publisher: Wiley
Date: 09-2000
Publisher: Elsevier
Date: 2009
Publisher: Elsevier BV
Date: 06-1984
Publisher: Wiley
Date: 2002
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 08-2007
Publisher: Springer Science and Business Media LLC
Date: 20-01-2016
DOI: 10.1038/PJ.2015.139
Publisher: Wiley
Date: 03-08-2011
Publisher: Springer Science and Business Media LLC
Date: 18-04-2012
DOI: 10.1038/PJ.2012.56
Publisher: Elsevier
Date: 2017
Publisher: Wiley
Date: 12-2015
DOI: 10.1111/COTE.12185
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN10001
Abstract: A convenient method for measuring the clean colour (Y and Y-Z) and photostability Δ(Y-Z) of small s les of fleece wool (0.5 g) is described. Scoured wool s les are compressed to a constant density in disposable polymethyl methacrylate spectrophotometer cells and the wool colour is measured using a standard textile laboratory reflectance spectrophotometer. Packing scoured wool into cells ensures that the irradiated fibre surface is robust and in idual fibres are unable to move relative to one another during irradiation and measurement. A UVB (280–320 nm) source was used to ensure all s les regardless of initial yellowness were yellowed following exposure and photobleaching was avoided. An apparatus capable of irradiating up to 48 scoured wool s les in one batch is described. The precision of photostability measurements was assessed and the relative error in Δ(Y-Z) was 5.7%. An initial study on 75 fleece wool s les with a high range of initial yellowness showed a moderate linear correlation (R2 = 0.68) between initial yellowness and Δ(Y-Z).
Publisher: Informa UK Limited
Date: 06-2013
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 12-2016
Publisher: Wiley
Date: 22-10-2009
DOI: 10.1111/J.1751-1097.2009.00614.X
Abstract: Fibrous proteins discolor on exposure to the UV component of sunlight. This effect is exacerbated in the presence of fluorescent whitening agents (FWAs), which are often applied to textiles to improve product brightness. Tryptophan photoproducts have been identified as significant contributors to protein photoyellowing however, the role of non-tryptophan-derived chromophores is less clear. In this study bovine collagen, containing no tryptophan residues, was irradiated in the presence and absence of the stilbene-derived FWA, 4,4'-bis(2-sulfostyryl)biphenyl (DSBP) and photoproducts were identified using mass spectrometry. Photoyellowing was found to be dependent on the presence of the FWA, attributed to lified generation of reactive oxygen species (ROS), particularly hydroxyl radicals and peroxynitrite. Four key proteinaceous photomodifications contributing directly to photoyellowing were located in irradiated collagen pretreated with DSBP, namely dopa, nitrophenylalanine, nitrotyrosine and nitrohistidine. This represents the first direct characterization of the three nitrated residues in the photoyellowing of an isolated fibrous protein, and implicates the ROS, peroxynitrite, as a key contributor to protein photoyellowing. Direct oxidative modification of the FWA itself was also observed. This study demonstrates that, even in the absence of tryptophan residues, significant photomodification of protein residues leading to chromophore formation occurs in the presence of an FWA.
Publisher: Informa UK Limited
Date: 23-06-2015
Publisher: Wiley
Date: 18-07-2006
Publisher: Wiley
Date: 16-03-2009
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.JPHOTOBIOL.2012.05.022
Abstract: Several previous studies have reported luminescence emission from skin following exposure to UVA radiation in air. We show that UVA irradiation of biomaterials and polymers in oxygen, including bovine stratum corneum, followed by photon counting results in a complex emission due to a combination of photophysical processes together with photo-induced chemiluminescence (PICL). The photophysical processes include fluorescence, phosphorescence and charge-recombination luminescence. By irradiating materials in an inert atmosphere such as nitrogen and allowing photophysical light emission to fully decay before admitting oxygen, the weak photo-induced chemiluminescence generated via free radical reactions with oxygen can be separated and analysed. PICL emission from bovine stratum corneum is weaker than for wool keratin and bovine skin collagen, probably due to its higher water content, and the presence of the natural antioxidants ascorbate and tocopherol.
Publisher: Elsevier BV
Date: 07-2004
Publisher: Wiley
Date: 18-10-2007
DOI: 10.1111/J.1751-1097.2007.00210.X
Abstract: The application of fluorescent whitening agents (FWAs) significantly accelerates the photoyellowing of wool and silk under exposure to the ultraviolet and visible components of sunlight <500 nm. The photochemistry involved in this process is poorly understood, particularly the role of photoproducts derived directly from the FWA itself. Hydroxylation was identified as the key initial mechanism of photodegradation leading to coloration of the solution in the irradiation of the stilbene-derived FWA 4,4'-bis(2-sulfostyryl)biphenyl (DSBP) in the presence of hydrogen peroxide (H2O2). Polyhydroxylated DSBP derivatives were implicated as critical intermediates in the formation of yellow photoproducts under these conditions. The formation of trace quantities of DSBP quinone derivatives subsequent to hydroxylation was identified as the key cause of DSBP photoyellowing. These results are the first successful characterization of yellow photoproducts resulting directly from irradiation of a stilbene-based FWA. Formation of these yellow stilbene-based FWA-derived photoproducts may occur on the surface of FWA-treated wool exposed to simulated sunlight, as previous work has shown that H2O2 is photogenerated when wet FWA-treated wool is exposed to light. These results therefore suggest that yellow FWA-derived photoproducts contribute to the accelerated photoyellowing of FWA-treated wool.
Publisher: Wiley
Date: 10-06-2016
DOI: 10.1002/APP.43963
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.JPHOTOBIOL.2009.11.008
Abstract: Photo-oxidation of proteinaceous fibres correlates directly to lowered appearance retention and performance, with particular commercial significance for wool and human hair. We here outline the first detailed proteomic evaluation of differential photo-oxidation occurring in the cuticle and cortex of wool fibres. After exposure of whole wool to UVB irradiation, physical disruption techniques designed to minimise further oxidative modification were utilised to prepare enriched cuticle and cortex fractions. This was followed by comprehensive redox proteomic analyses of photo-oxidation via the location within the fibre components of modifications to aromatic residues. An oxidative classification system was developed and applied to provide further insight into differential photo-oxidation. These results were compared with coloration changes observed within the cuticular and cortical components of the fibre. In this study, although the cuticle was observed to have a higher level of baseline oxidation, the cortex exhibited significantly higher levels of photo-oxidation under UVB irradiation. These proteomic results were supported by the observation of significantly higher photoyellowing within the cortex than within the cuticle. It has been assumed that fibre photo-oxidation was predominantly confined to the wool cuticle, and that changes within the cuticle had the greatest effect on appearance retention. These results provide new insight into the contribution of the cortex to photo-induced discoloration of proteinaceous animal fibres.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.2414
Abstract: Chemiluminescence (CL) is a straightforward method for studying the free radical degradation of organic and biological materials. A simple modification to a commercial thermal CL instrument and an effective experimental protocol allows the study of photoinduced chemiluminescence (PICL) emission. PICL originates from the reactions of macroperoxy radical intermediates formed during the autoxidation chain reaction. We have applied the PICL technique to study the photooxidation of polymer films and coatings, fibrous webs such as textile fabrics or paper, and powdered s les. Oxygen permeability appears to be a key factor affecting the intensity of PICL emission from polymer films.
Publisher: Royal Society of Chemistry (RSC)
Date: 1987
DOI: 10.1039/DT9870001521
Publisher: Informa UK Limited
Date: 16-03-2016
Publisher: Elsevier BV
Date: 2014
Publisher: Wiley
Date: 05-10-2012
DOI: 10.1002/BIO.1359
Abstract: Thermal luminescence (TL) spectra of polyamides were measured with a Fourier-transform chemiluminescence spectrometer to elucidate the emission mechanism. A TL band of ε-polylysine with a peak at 542 nm observed at 403 K was assigned to the emission due to the interaction of the -CO-NH- group with oxygen molecules by comparison with nylon-6, polyglycine, and polyalanine. When the s le was kept at 453 K, the intensity of the TL band decreased and the wavelength of the peak shifted to 602 nm, which was assigned to the emission due to the interaction of the NH2 group on the side chain with oxygen molecules by comparison with monomeric lysine. A weak emission with a peak at 668 nm was assigned to the advanced glycosylation end products (AGEs) yielded by the Maillard reaction with a catalytic amount of water. To understand this reaction and to examine the TL emission of AGEs, we measured TL spectra of mixtures of polylysine and reducing sugars such as glucose, maltose, lactose, and dextrin. The minimum temperature for TL emission, wavelength of the peak and the relative intensities of the TL emission were found to depend on the size of the sugars.
Publisher: Elsevier BV
Date: 10-2007
Publisher: Wiley
Date: 26-11-2014
DOI: 10.1111/COTE.12109
Publisher: Informa UK Limited
Date: 21-12-2016
Publisher: Elsevier BV
Date: 10-2007
Publisher: No publisher found
Date: 2008
DOI: 10.1016/J.JPHOTOBIOL.2008.05.011
Abstract: The wool fibre has a complex morphology, consisting of an outer layer of cuticle scales surrounding an inner cortex. These two components are hard to separate effectively except by using harsh chemical treatments, making it difficult to determine the susceptibility of the different components of the fibre to photoyellowing. An approach to this problem based on mechanical fibre modification is described. To expose the inner cortex of wool to different degrees, clean wool fibres were converted into 'powders' of various fineness via mechanical chopping, air-jet milling, ball milling or their combination. Four types of powdered wool (s les A, B, C and D) were produced with reducing particle size distributions and an increasing level of surface damage as observed using SEM. S le A contained essentially intact short fibre snippets and s le D contained a large amount of exposed cortical materials. S les B and C contained a mixture of short fibre snippets and cortical materials. Solid wool discs were then compressed from the corresponding powder s les in a polished stainless steel die to enable colour measurement and UV irradiation studies. ATR-FTIR studies on powder discs demonstrated a small shift in the amide I band from 1644cm(-1) for disc A to 1654cm(-1) for disc D due to the different structures of the wool cuticle and cortex, in agreement with previous studies. Similarly an increase in the intensity ratio of the amide I to amide II band (1540cm(-1)) was observed for disc D, which contains a higher fraction of cortical material at the surface of the disc. Discs prepared from s le D appeared the lightest in colour before exposure and had the slowest photoyellowing rate, whereas discs made from powders A-C with a higher level of cuticle coverage were more yellow before exposure and experienced a faster rate of photoyellowing. This suggests that the yellow chromophores of wool may be more prevalent in cuticle scales, and that wool photoyellowing occurs to a greater extent in the cuticle than in the cortex. Photo-induced chemiluminescence measurements showed that s le D had a higher chemiluminescence intensity after exposure to UVA radiation and a faster decay rate than s les A and B. Thus one of the roles of the wool cuticle may be to protect the cortex by quenching of free radical oxidation during exposure to the UV wavelengths present in sunlight.
Publisher: Wiley
Date: 16-11-2006
Publisher: Springer Science and Business Media LLC
Date: 05-01-2012
DOI: 10.1007/S00726-011-1201-Y
Abstract: UV-visible diffuse reflectance (DR) spectra of the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen are presented. Natural wool contains much higher levels of visible chromophores across the whole visible range (700-400 nm) than the other proteins and only those above 450 nm are effectively removed by bleaching. Both oxidative and reductive bleaching are inefficient for removing yellow chromophores (450-400 nm absorbers) from wool. The DR spectra of the four UV-absorbing amino acids tryptophan, tyrosine, cystine and phenylalanine were recorded as finely ground powders. In contrast to their UV-visible spectra in aqueous solution where tryptophan and tyrosine are the major UV absorbing species, surprisingly the disulphide chromophore of solid cystine has the strongest UV absorbance measured using the DR remission function F(R)(∞). The DR spectra of unpigmented feather and wool keratin appear to be dominated by cystine absorption near 290 nm, whereas silk fibroin appears similar to tyrosine. Because cystine has a flat reflectance spectrum in the visible region from 700 to 400 nm and the powder therefore appears white, cystine absorption does not contribute to the cream colour of wool despite the high concentration of cystine residues near the cuticle surface. The disulphide absorption of solid L: -cystine in the DR spectrum at 290 nm is significantly red shifted by ~40 nm relative to its wavelength in solution, whereas homocystine and lipoic acid showed smaller red shifts of 20 nm. The large red shift observed for cystine and the large difference in intensity of absorption in its UV-visible and DR spectra may be due to differences in the dihedral angle between the crystalline solid and the solvated molecules in solution.
Publisher: SAGE Publications
Date: 10-05-2013
Abstract: We evaluated the feasibility of producing biodegradable mulch fabrics from bast fibers using a low-cost nonwoven fabric production process. Commercially available low-cost hemp and linseed flax fibers were carded, lightly needle-punched and then consolidated using a hydroentanglement process to produce fabrics around 200 g/m 2 and 0.5 mm thickness. The hydroentanglement process liberated micro and nanofibers that formed a continuous fibrous network entangling and linking the parent fibers to produce fabrics with good tensile properties. Preliminary field trials of the fabrics demonstrate that they can be used to suppress weeds when colored with a commercially available carbon black-based mulch colorant. When in contact with soil the fabric biodegraded and lost strength in a matter of a few months.
Publisher: American Chemical Society (ACS)
Date: 19-09-2013
DOI: 10.1021/BM401023H
Abstract: A silk cocoon protects a silkworm during its pupal stage from various threats. We systematically investigated the role of fiber, sericin, and embedded crystals in the UV protection of a silk cocoon. Diffuse reflectance and UV absorbance were measured and free radicals generated during exposure to UV radiation were quantified using photoinduced chemiluminescence (PICL). We identified the response to both UV-A and UV-B radiations by silk materials and found that sericin was primarily responsible for UV-A absorption. When sericin was removed, the photoinduced chemiluminescence intensity increased significantly, indicating higher UV-A-induced reactions of cocoons in the absence of sericin. There is progressively higher sericin content toward the outer part of the cocoon shell that allows an effective shield to pupae from UV radiation and resists photodegradation of silk fibers. The study will inspire development of advanced organic photoprotective materials and designing silk-based, free-radical-scavenging antioxidants.
Publisher: Informa UK Limited
Date: 06-2013
Publisher: Wiley
Date: 1996
DOI: 10.1002/(SICI)1520-6343(1996)2:4<249::AID-BSPY6>3.0.CO;2-1
Publisher: Elsevier BV
Date: 10-2014
Publisher: Springer Science and Business Media LLC
Date: 11-09-2014
Publisher: Elsevier
Date: 2008
Publisher: Springer Science and Business Media LLC
Date: 2009
Publisher: SAGE Publications
Date: 06-1998
DOI: 10.1177/004051759806800605
Abstract: The Siroflash anti-pilling treatment for knitted fabrics is a process involving exposure of the fabric or garment surface to short wavelength ultraviolet radiation (UVC), fol lowed by a mild wet oxidation treatment using, for ex le, hydrogen peroxide or salts of permonosulphuric acid. UVC exposure is confined to the surface fibers and presensitizes them to the wet oxidation process, which selectively weakens them rel ative to the bulk fibers responsible for fabric strength. Because the surface fibers are much weaker after treatment, no anchor fibers are available to secure pills to the fabric surface. The treatment is a highly effective, chlorine-free method of preventing pilling in wool knitwear, which has now been demonstrated in wear trials. In addition. uv treatment of knitted garments prior to aqueous oxidation can effectively limit facing, up in wool knitwear during garment dyeing. A variation of the Siroflash process can also be used on cotton and cotton/wool blend fabrics by first padding hydrogen per oxide onto the fabric before UV exposure, then treating with continuous uv irradiation with a medium-pressure arc system similar to those used commercially for UV curing of polymer films. However, the continuous process is ineffective on pure wool knitted fabrics. The irradiation times necessary for effective treatment on wool using low power germicidal uv tubes vary depending on fabric or garment construction. Using these sources, however, irradiation times are too long for commercial use, and continuous exposure with a focused medium-pressure mercury arc is only partially effective. More powerful uv sources providing a high level of UVC radiation, for ex le noncoherent excimers or high-intensity low pressure arcs, or hybrid methods for weakening surface fibers (such as UV/H 2 O 2 with a protease enzyme) may provide a rapid, effective, anti- pilling treatment for wool.
Publisher: SAGE Publications
Date: 07-03-2012
Abstract: High levels (50–70%) of permanent set were obtained when wet pure wool fabric was heated rapidly to 110–130°C for up to 1 minute under conditions that limit the evaporation of water. If the final regain of the fabric after treatment was less than 34%, lower levels of permanent set were generally observed. If the initial regain was less than 34%, permanent set levels were invariably % and the specimens were usually damaged by scorching due to the low heat capacity and poor thermal conductivity of wool compared with water. This result precludes the use of a rapid chemical-free permanent setting process based on conductive heat transfer at the dry finishing stage. Under more severe conditions (higher temperatures or longer pressing times) significant shrinkage, yellowing and fabric damage due to supercontraction were observed. The high level of permanent set obtained in this study suggests that the performance of continuous crabbing machines could be improved by optimizing the treatment conditions without the need for chemical setting agents.
Publisher: Springer Science and Business Media LLC
Date: 06-01-2013
DOI: 10.1007/S12011-012-9579-2
Abstract: The presence of copper and iron in metal-doped wool has been shown previously to be associated with the production of free radicals and yellowing in photo-irradiated wool. In this study, the yellowness and trace metal content of 700 wool s les was measured to determine if photoyellowing, catalysed by metals, is a major determinant of the colour of fleece wool. Iron and copper content did not positively correlate with yellowness and yellower wool tended to have lower levels of these metals. Instead, a strong positive correlation of yellowness with the calcium, manganese and magnesium content was observed in yellow wools. High levels of calcium and magnesium is consistent with biofilm formation by Pseudomonas bacteria that have previously been associated with non-scourable staining of wool.
Publisher: Elsevier BV
Date: 12-2013
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN09117
Abstract: This study determines how levels of various trace metals in wool and the colour of the fibre change as a result of sunlight exposure and treatment with chelating compounds during wool growth. Twenty-four yearling Merino sheep were clipped on the shoulders and rumps and fitted with sheep coats modified with transparent patches. Patches over the shoulder wool (one per sheep) were either polyethylene (PE) that transmits ultraviolet light or polyvinyl chloride (PVC) that excludes ultraviolet light. The rump wool on each sheep was treated either with a copper chelator treatment (kojic acid or methyl gentisate in aqueous alcohol) or aqueous alcohol only. For 12 of the sheep the rumps were exposed to sunlight through PE patches while rump wool on the other sheep was covered by the sheep coat. Wool was harvested after 11 weeks’ growth with yellowness (Y-Z) and in idual mineral contents measured using the same clean wool s le. Sunlight exposure through PE patches caused a mean increase in Y-Z to 9.1 (shoulder) or 9.5–10.1 (rump) from a base level of 7.1–7.2 (shoulder) or 7.0–7.6 (rump) in wool protected by the sheep coat. In contrast, there was no significant change in Y-Z for the PVC patch (shoulder). Therefore, it appears that ultraviolet light damage caused the increased Y-Z. Most of the trace metals analysed increased in the shoulder wool exposed to sunlight but the paired differences for PVC were lower than PE. It appears that changes in fibre caused by sunlight exposure (especially ultraviolet light) facilitate adsorption of minerals from the environment, including the animal’s own suint. Application of the chelating compounds to the rump wool caused pronounced yellowing of the wool with Y-Z increase being most pronounced for kojic acid. Copper levels in the wool were reduced by kojic acid and methyl gentisate while calcium levels were increased by kojic acid and reduced by methyl gentisate. It is not clear from these findings whether minerals and copper in particular contribute to yellowing of wool. However, the different effects of sunlight and chelation on mineral contents in wool shown may well relate to alternative mechanisms of discoloration (i.e. photoyellowing versus bacterial).
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JPHOTOBIOL.2014.02.018
Abstract: One of the current concerns with the application of nanoparticles in sunscreens, and in particular nano-TiO2 and ZnO, is their potential to photogenerate free radicals and reactive oxygen species (ROS) when they absorb ultraviolet wavelengths from sunlight. Free radicals and ROS are known to be associated with UV-induced skin damage and oxidative stress, from which sunscreens are expected to offer significant protection. Here we describe a simple method, based on chemiluminescence emission, for detecting free radicals generated in commercial sunscreens alone, and when applied to various substrates, following exposure to UVA (320-400nm) radiation. This photo-induced chemiluminescence (PICL) technique could be used to optimise sunscreen formulations so as to minimise free radical photogeneration during exposure to sunlight.
Publisher: Wiley
Date: 17-06-2013
DOI: 10.1111/COTE.12039
Publisher: Elsevier BV
Date: 02-2009
Publisher: Elsevier BV
Date: 07-1997
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN09231
Abstract: The degree of light penetration along the length of the fibre of a simulated Merino fleece was measured using a fibre optic probe to investigate the relationship between light exposure and photodamage to the wool fibre. The percentage of the total direct sunlight that reached the base of the 100-mm long, simulated, closed Merino fleece was ~1% and the section of the fibre from the root to 60 mm from the root was protected from exposure. The light intensity at the base of the fibre was increased to 2% when the density of the simulated fleece was halved. Wool was scoured and the yellowness and intensity of methylene blue staining was measured to estimate the extent of damage to wool staples.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2010
DOI: 10.1007/S00726-009-0352-6
Abstract: Chemiluminescence (CL) with maximum emission in the range 550-650 nm is observed when proteins and certain amino acids are heated in air, and CL intensity is significantly reduced in nitrogen. Of the 20 common amino acids, lysine (Lys) has the highest thermal CL intensity by a factor of approximately 30 over arginine, threonine and asparagine. This finding differs from previous studies on amino acids and proteins oxidised using free radical initiators or singlet oxygen, where tryptophan was the dominant factor for CL emission. CL from heating solid Lys in air is accompanied by browning and the generation of fluorescent products which are characteristic of advanced glycosylation end products (AGEs) in thermally treated milk proteins. During thermal oxidation, Lys may react with its own carbonyl oxidation products to form fluorescent compounds similar to AGEs via the formation of Schiff bases. The mechanism of thermal oxidation of proteins may be similar to polyamide polymers, where reaction of free primary amino groups with carbonyls to form Schiff bases plays a key role.
Publisher: Elsevier BV
Date: 05-2015
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Keith Millington.