Research on the influence of yarn parameters on the ultraviolet protection of yarns

Considering both the yarn parameters and the light interaction (reflectance and transmittance) between two adjacent yarns, an optical model was presented to understand the ultraviolet (UV) light penetrating a single undyed yarn and a lot of yarns. The optical model was verified with results of diffuse reflectance spectra measurement on wool yarn samples. This optical model was used to predict the factors influencing UV protection, including fibre diameter, yarn linear density, yarn twist, transmittance index and refractive index. The statistical predictive model was also set up to show the relationship between the yarn parameters and the UV protection (UPF values) of the yarns. Yarns with the fine diameter, large yarn linear density and low yarn twist had the high UV protection.

Detection of Arabidopsis thaliana AtRAD1 cDNA variants and assessment of function by expression in a yeast rad1 mutant

The Saccharomyces cerevisiae RAD1 and human XPF genes encode a subunit of a nucleotide excision repair endonuclease that also is implicated in some forms of homologous recombination. An Arabidopsis thaliana gene (AtRAD1) encoding the orthologous plant protein has been identified recently. Here we report the isolation of three structurally distinct AtRAD1 cDNAs from A. thaliana leaf tissue RNA. One of the isolates (AtRAD1-1) corresponds to the cDNA previously shown to encode the full-length AtRad1 protein, whereas the other two (AtRAD1-2, AtRAD1-3) differ slightly in size due to variations at the 5′ end of exon 6 or the 3′ end of exon 7, respectively. The sequence differences argue that these cDNAs were probably templated by mRNAs generated via alternative splicing. Diagnostic polymerase chain reaction pointed to the presence of the AtRAD1-1 and AtRAD1-2 but not AtRAD1-3 transcripts in bud and root tissue, and to a fourth transcript (AtRAD1-4), having both alterations identified in AtRAD1-2 and AtRAD1-3, in root tissue. However, the low frequency of detection of AtRAD1-3 and AtRAD1-4 makes the significance of these tissue-specific patterns unclear. The predicted AtRad1-2, AtRad1-3 and AtRad1-4 proteins lack part of the region likely required for endonuclease complex formation. Expression of AtRAD1-2 and AtRAD1-3 in a yeast rad1 mutant did not complement the sensitivity to ultraviolet radiation or the recombination defect associated with the rad1 mutation. These results suggest that alternative splicing may modulate the levels of functional AtRad1 protein.

Adolescents' use of purpose built shade in secondary schools : cluster randomised controlled trial

Objective To examine whether students use or avoid newly shaded areas created by shade sails installed at schools.

Design Cluster randomised controlled trial with secondary schools as the unit of randomisation.

Setting 51 secondary schools with limited available shade, in Australia, assessed over two spring and summer terms.

Participants Students outside at lunch times.

Intervention Purpose built shade sails were installed in winter 2005 at full sun study sites to increase available shade for students in the school grounds.

Main outcome measure Mean number of students using the primary study sites during weekly observations at lunch time.

Results Over the study period the mean change in students using the primary study site from pre-test to post-test was 2.63 (95% confidence interval 0.87 to 4.39) students in intervention schools and –0.03 (–1.16 to 1.09) students in control schools. The difference in mean change between groups was 2.67 (0.65 to 4.68) students (P=0.011).

Conclusions Students used rather than avoided newly shaded areas provided by purpose built shade sails at secondary schools in this trial, suggesting a practical means of reducing adolescents’ exposure to ultraviolet radiation.

Trial registration Exempt.

Repair and tolerance of DNA damage in higher plants

DNA repair mechanisms constitute an essential cellular response to DNA damage arising either from metabolic processes or from environmental sources such as ultraviolet radiation. Repair of these lesions may be via direct reversal, or by processes such as nucleotide excision repair (NER), a coordinated pathway in which lesions and the surrounding nucleotides are excised and replaced via DNA resynthesis. The importance of repair is illustrated by human disease states such as xeroderma pigmentosum and Cockayne's syndrome which result from defects in the NER system arising from mutations in XP- genes or XP- and CS- genes respectively Little detail is known of DNA damage repair processes in plants, despite the economic and ecological importance of these organisms. This study aimed to expand our knowledge of the process of NER in plants, largely via a polymerase chain reaction (PCR)-based approach involving amplification, cloning and characterisation of plant genomic DNA and cDNA. Homologues of the NER components XPF/RAD1 and XPD/RAD3 were isolated as both genomic and complete cDNA sequences from the model dicotyledonous plant Arabidopsis thaliana. The sequence of the 3'-untranslated region of atXPD was also determined. Comparison of genomic and cDNA sequences allowed a detailed analysis of gene structures, including details of intron/exon processing. Variable transcript processing to produce three distinct transcripts was found in the case of atXPF. In an attempt to validate the proposed homologous function of these cDNAs, assays to test complementation of resistance to ultraviolet radiation in the relevant yeast mutants were performed. Despite extensive amino acid sequence conservation, neither plant cDNA was able to restore UV-resistance. As the yeast RAD3 gene product is also involved in vivo in transcription, and so is required for viability, the atXPD cDNA was tested in a complementation assay for this function in an appropriate yeast mutant. The plant cDNA was found to substantially increase the viability of the yeast mutant. The structural and functional significance of these results is discussed comparatively with reference to yeast, human and other known homologues. Other putative NER homologues were identified in A. thaliana database sequences, including those of ERCC1/RAD10 and XPG/ERCC5/RAD2, and are now the subjects of ongoing investigations. This study also describes preliminary investigations of putative REVS and RAD30 translesion synthesis genes from A. thaliana.

Isolation and characterisation of Arabidopsis RAD30 and ERCC1

This thesis describes the isolation and characterisation of two plant genes, AtERCC1 and AtRAD30. Evidence from protein homology comparisons, and functional complementation, in vitro mutagenesis, or interaction assays suggests the involvement of these genes in the repair or tolerance, respectively, of UV-induced DNA change.

Influence of age on expression of DNA repair genes in Arabidopsis

Numerous studies suggest that ageing in mammals may be associated with a reduction in DNA repair, whereas little is known about the DNA repair capacity of plants as they age. In this study we examined the effects of ageing on the expression of genes thought to be involved in nucleotide excision repair (AtERCC1, AtGTF2H2, AtGTF2H5, AtXPB1, AtXPD, AtXPF) or translesion replication (AtPOLH, AtREV1, AtREV3, AtUBC2) of UV photoproducts in Arabidopsis (Arabidopsis thaliana). Two- or four-week old plants were unirradiated or treated with 254 nm ultraviolet (UV) radiation (0.75 or 1.5 kJm^-2), incubated for 3 or 9 hr, and gene expression was analysed via quantitative PCR. With the exception of AtPOLH, transcript levels for all genes investigated were at least four-fold greater in unirradiated four-week old plants than unirradiated two-week old plants. Compared to unirradiated age-matched plants, two-week old plants generally showed no consistent change in transcript levels for either UV dose or post-irradiation incubation period. On the other hand, transcript levels in four-week old plants were increased over those in two-week old plants for the majority of genes by 9 hr post-irradiation with 0.75 or 1.5 kJm^-2 UV. No other consistent responses were observed for UV treatment. Collectively, our results are consistent with the possibility that ageing may be associated with increased DNA repair capacity in plants.

Seasonal periodicity of serum vitamin D and parathyroid hormone, bone resorption, and fractures : the Geelong Osteoporosis Study

In this population-based study, seasonal periodicity was seen with reduced serum vitamin D, increased serum PTH, and increased bone resorption in winter. This was associated with an increased proportion of falls resulting in fracture and an increased risk of wrist and hip fractures.

Introduction: In a population of women who reside in a temperate climate and do not generally receive dietary vitamin D supplementation, we investigated whether seasonal vitamin D insufficiency is associated with increased risk of fracture.

Materials and Methods: An observational, cross-sectional, population-based study set in southeastern Australia (latitude 38–39° S). Participants were drawn from a well-defined community of 27,203 women ≥55 years old: 287 randomly selected from electoral rolls, 1635 with incident fractures, and 1358 presenting to a university hospital with falls. The main outcome measures were annual periodicities of ultraviolet radiation, serum 25-hydroxyvitamin D [25(OH)D], serum parathyroid hormone (PTH), serum C-telopeptide (CTx), BMD, falls, and fractures.

Results: Cyclic variations in serum 25(OH)D lagged 1 month behind ultraviolet radiation, peaking in summer and dipping in winter (p < 0.001). Periodicity of serum PTH was the inverse of serum 25(OH)D, with a phase shift delay of 1 month (p = 0.004). Peak serum CTx lagged peak serum PTH by 1–2 months. In late winter, a greater proportion of falls resulted in fracture (p < 0.001). Seasonal periodicity in 439 hip and 307 wrist fractures also followed a simple harmonic model (p = 0.078 and 0.002, respectively), peaking 1.5–3 months after the trough in 25(OH)D.

Conclusions: A fall in 25(OH)D in winter is accompanied by increases in (1) PTH levels, (2) bone resorption, (3) the proportion of falls resulting in fracture, and (4) the frequency of hip and wrist fracture. Whether vitamin D supplementation in winter can reduce the population burden of fractures requires further investigation.

Maximising students' use of purpose-built shade in secondary schools: Quantitative and qualitative results of a built-environment intervention

A trial installing shade sails at secondary schools found increased students' use of newly shaded areas, but relatively low use overall. We examined site features and weather related to use of these shaded areas. Tables with seats and temperatures ≥27 °C increased student use of shaded areas, presence of grass decreased use. Focus groups at eight schools suggest students were unaware of changes to their habitual use of favoured locations. Results infer careful selection of locations for built-shade and provision of tables with seats will assist in maximising student use and investments in shade sails.

Future health implications of prenatal and early-life vitamin D status

Current or recent low vitamin D status (or proxy measures such as dietary intake or ambient ultraviolet radiation) is linked to several chronic diseases, including osteoporosis, cancers, and cardiovascular and autoimmune diseases. Low prenatal vitamin D status may also increase susceptibility to such diseases in later life via specific target organ effects and/or through changes to the developing immune system. Maternal vitamin D supplementation during pregnancy could be an important public health measure to decrease risk of a range of chronic diseases, but further research is required to clarify beneficial and adverse effects of high prenatal vitamin D.

Ocular exposure to UV-B in sunlight: the Melbourne Visual Impairment Project model

Quantification of ocular exposure to ultraviolet-B radiation (UV-B) has become an important public health issue, with reports that the ozone layer is being depleted worldwide. Ocular exposure to UV-B is determined by ambient UV-B levels, the duration of outdoor exposure, the proportion of ambient UV-B that reaches the eye, and the use of ocular protection. We have developed a simplified model for quantifying lifetime ocular UV-B exposure that can be used in large epidemiological surveys. Exposure to UV-B is assessed and quantified using a model based on personal exposure over the six summer months. Data available for a population-based sample of 1150 people in the age range 40-98 years revealed a distribution in average annual lifetime ocular UV-B exposure similar to that reported in a previous study on which this model is based, and also demonstrate that people can recall lifetime personal behaviour related to ocular protection. It takes 12 minutes on average to collect these data. This model can be employed by researchers worldwide for uniform assessment of ocular UV-B exposure.

Immune modulation by vitamin D and its relevance to food allergy

Apart from its classical function in bone and calcium metabolism, vitamin D is also involved in immune regulation and has been linked to various cancers, immune disorders and allergic diseases. Within the innate and adaptive immune systems, the vitamin D receptor and enzymes in monocytes, dendritic cells, epithelial cells, T lymphocytes and B lymphocytes mediate the immune modulatory actions of vitamin D. Vitamin D insufficiency/deficiency early in life has been identified as one of the risk factors for food allergy. Several studies have observed an association between increasing latitude and food allergy prevalence, plausibly linked to lower ultraviolet radiation (UVR) exposure and vitamin D synthesis in the skin. Along with mounting epidemiological evidence of a link between vitamin D status and food allergy, mice and human studies have shed light on the modulatory properties of vitamin D on the innate and adaptive immune systems. This review will summarize the literature on the metabolism and immune modulatory properties of vitamin D, with particular reference to food allergy.

UV interactions with fibres and fibrous structures

 In this research, the effects of fibre, yarn and fabric parameters on the UV protective properties were studied, and the results were interpreted by various developed models. An optimised knitted fabric for a lightweight spring/summer application with high UV protection and good thermal comfort was proposed from this systematic investigation.

Can Peto's paradox be used as the null hypothesis to identify the role of evolution in natural resistance to cancer? A critical review

BACKGROUND: Carcinogenesis affects not only humans but almost all metazoan species. Understanding the rules driving the occurrence of cancers in the wild is currently expected to provide crucial insights into identifying how some species may have evolved efficient cancer resistance mechanisms. Recently the absence of correlation across species between cancer prevalence and body size (coined as Peto's paradox) has attracted a lot of attention. Indeed, the disparity between this null hypothesis, where every cell is assumed to have an identical probability to undergo malignant transformation, and empirical observations is particularly important to understand, due to the fact that it could facilitate the identification of animal species that are more resistant to carcinogenesis than expected. Moreover it would open up ways to identify the selective pressures that may be involved in cancer resistance. However, Peto's paradox relies on several questionable assumptions, complicating the interpretation of the divergence between expected and observed cancer incidences. DISCUSSIONS: Here we review and challenge the different hypotheses on which this paradox relies on with the aim of identifying how this null hypothesis could be better estimated in order to provide a standard protocol to study the deviation between theoretical/theoretically predicted and observed cancer incidence. We show that due to the disproportion and restricted nature of available data on animal cancers, applying Peto's hypotheses at species level could result in erroneous conclusions, and actually assume the existence of a paradox. Instead of using species level comparisons, we propose an organ level approach to be a more accurate test of Peto's assumptions. SUMMARY: The accuracy of Peto's paradox assumptions are rarely valid and/or quantifiable, suggesting the need to reconsider the use of Peto's paradox as a null hypothesis in identifying the influence of natural selection on cancer resistance mechanisms.

Use of ultraviolet C (UVC) radiation to inactivate infectious hematopoietic necrosis virus (IHNV) and viral haemorrhagic septicaemia virus (VHSV) in fish processing plant effluent

We determined the stability of infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) suspended in either fish processing plant effluent blood water (EBW) or culture media and examined the effectiveness of UVC radiation to inactivate IHNV and VHSV suspended in both solutions. Without exposure to UVC, IHNV and VHSV were maintained in 4°C blood water for up to 48 hours without significant reduction in virus titer. However when exposed to UVC radiation using a low pressure mercury vapour lamp collimated beam, IHNV and VHSV were inactivated, and the efficacy of UVC radiation was dependent upon the solution and virus type being treated. A 3-log reduction for VHSV and IHNV in culture media was achieved at 3.28 and 3.84 mJ cm-2, respectively. The UV dose needed for a 3-log reduction of VHSV in EBW was 3.82 mJ cm-2. However, exposure of IHNV in EBW to the maximum UVC dose tested (4.0 mJ cm-2) only led to a 2.26-log-reduction. Factors such as particle size, and possible association of viruses with suspended EBW particulate, were not investigated in this study, but may have contributed to the difference in UVC effectiveness. Future work should emphasize improved filtration methods prior to UV treatment of processing plant EBW at an industrial scale.