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81.
Childhood sun exposure is linked to excessive pigmented mole development and melanoma risk. Clothing provides a physical barrier, protecting skin from ultraviolet radiation (UVR). Extending sleeves to elbow length and shorts to knee length has been shown to significantly reduce mole acquisition in preschoolers from tropical Queensland. We used publicly available uniform images and guidelines from primary schools in Townsville (latitude 19.25°S, n = 43 schools), Cairns (16.87°S, n = 46) and the Atherton Tablelands (17.26°S, n = 23) in tropical Australia to objectively determine the body surface proportion covered by regulation school uniforms. Uniforms of nongovernment, large (≥800 students), urban, educationally advantaged schools with comprehensive sun protection policies covered more skin than those of government schools (63.2% vs 62.0%; P < 0.001), smaller schools (63.4% vs 62.3%; P = 0.009), rural (62.7% vs 61.9%; P = 0.002) and educationally disadvantaged schools (62.8% vs 62.3%; P < 0.001) with underdeveloped sun protection policies (62.8% vs 62.2%; P = 0.002). Overall, SunSmart and non‐SunSmart school uniforms covered identical body surface proportions (62.4%, P = 0.084). Although wearing regulation school uniforms is mandatory at most Australian primary schools, this opportunity to improve children's sun protection is largely overlooked. Recent evidence suggests that even encouraging minor alterations to school uniforms (e.g. slightly longer sleeves/dresses/skirts/shorts) to increase skin coverage may reduce mole acquisition and melanoma risk, especially in high‐risk populations. 相似文献
82.
Zacher D Yusenko K Bétard A Henke S Molon M Ladnorg T Shekhah O Schüpbach B de los Arcos T Krasnopolski M Meilikhov M Winter J Terfort A Wöll C Fischer RA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(5):1448-1455
The progressive liquid-phase layer-by-layer (LbL) growth of anisotropic multicomponent layer-based porous coordination polymers (PCPs) of the general formula [M(L)(P)(0.5)] (M: Cu(2+), Zn(2+); L: dicarboxylate linker; P: dinitrogen pillar ligand) was investigated by using either pyridyl- or carboxyl-terminated self-assembled monolayers (SAMs) on gold substrates as templates. It was found that the deposition of smooth, highly crystalline, and oriented multilayer films of these PCPs depends on the conditions at the early growth cycles. In the case of a two-step process with an equimolar mixture of L and P, growth along the [001] direction is strongly preferred. However, employing a three-step scheme with full separation of all components allows deposition along the [100] direction on carboxyl-terminated SAMs. Interestingly, the growth of additional layers on top of previously grown oriented seeding layers proved to be insensitive to the particular growth scheme and full retention of the initial orientation, either along the [001] or [100] direction, was observed. This homo- and heteroepitaxial LbL growth allows full control over the orientation and the layer sequence, including introduction of functionalized linkers and pillars. 相似文献
83.
Larson SE Li G Rowland GB Junge D Huang R Woodcock HL Antilla JC 《Organic letters》2011,13(9):2188-2191
Conditions for a catalytic asymmetric aza-Darzens aziridine synthesis mediated by a vaulted biphenanthrol (VAPOL) magnesium phosphate salt is described. Using simple substrates, this methodology explores the scope and reactivity of a new magnesium catalyst for an aziridination reaction capable of building chirality and complexity simultaneously. 相似文献
84.
85.
Stphane Cordier Kaplan Kirakci Guillaume Pilet Denise Mry Didier Astruc Andr Perrin Christiane Perrin 《Progress in Solid State Chemistry》2005,33(2-4):81-88
The [(M6L12i)L6a]n− and [(M6L8i)L6a] units (a = apical, i = inner) constitute the basic building blocks in the octahedral cluster chemistry. Nano-sized metallic clusters are easily obtained by solid state synthesis with transition elements associated with halogen or chalcogen. The intrinsic properties of M6 cluster units—one or two electron reversible redox process, magnetism and luminescence—depend on the nature of the metal and ligands. The solubilisation of M6 solid state compounds provides [(M6L12i)L6a]n− or [(M6L8i)L6a]n− building blocks with individual properties that can be further used for the design of hybrid organic/inorganic materials. Several examples of solid state precursors are presented as well as substitution reactions of apical ligands in solution. Indeed, hexacyano M6 clusters are obtained by direct reaction of solid state precursors in aqueous KCN solutions. Low dimensional frameworks are subsequently obtained by recrystallisation of hexacyano M6 clusters with transition elements. The functionalisation of cluster proceeds in two steps. The first one consists in the replacement of apical halogens of cluster unit precursors by labile groups as CF3SO3 (triflate) or solvent molecules after solution reaction. The second one consists in the substitution of the labile groups by functionalised phenolate or pyridine ligands. 相似文献
86.
Richard N. Butler Denise C. Grogan Luke A. Burke 《Journal of heterocyclic chemistry》1997,34(6):1825-1827
An unusual inverted V-shaped Hammett plot has been observed for substituent effects at the N-terminus of 1,2,3-triazolium-1-imide 1,3-dipoles in cycloaddition reactions. Theoretical studies (3-21G and 6-31G) suggest strong resonance interactions separately stabilizing both ends of the dipole. 相似文献
87.
88.
Henk Schierbeek Denise Rook Frans W. J. te Braake Kristien Y. Dorst Gardi Voortman Jean‐Philippe Godin Laurent‐Bernard Fay Johannes B. van Goudoever 《Rapid communications in mass spectrometry : RCM》2009,23(18):2897-2902
Determination of glutathione kinetics using stable isotopes requires accurate measurement of the tracers and tracees. Previously, the precursor and synthesized product were measured with two separate techniques, liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). In order to reduce sample volume and minimize analytical effort we developed a method to simultaneously determine 13C‐glutathione as its dimeric form (GSSG) and its precursor [1‐13C]glycine in a small volume of erythrocytes in one single analysis. After having transformed 13C‐glutathione into its dimeric form GSSG, we determined both the intra‐erythrocytic concentrations and the 13C‐isotopic enrichment of GSSG and glycine in 150 µL of whole blood using liquid chromatography coupled to LC/IRMS. The results show that the concentration (range of µmol/mL) was reliably measured using cycloleucine as internal standard, i.e. with a precision better than 0.1 µmol/mL. The 13C‐isotopic enrichment of GSSG and glycine measured in the same run gave reliable values with excellent precision (standard deviation (sd) <0.3‰) and accuracy (measured between 0 and 5 APE). This novel method opens up a variety of kinetic studies with relatively low dose administration of tracers, reducing the total cost of the study design. In addition, only a minimal sample volume is required, enabling studies even in very small subjects, such as preterm infants. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
89.
90.
W. D. Wallis 《Israel Journal of Mathematics》1971,10(3):349-358
SupposeA is a non-singular matrix with entries 0 and 1, the zero and identity elements of a Euclidean domain. We obtain a “best-possible”
lower bound for the number of equivalence invariants ofA (over the domain) which equal 1. From this it is proven that the sequence of invariants under integral equivalence of an
Hadamard matrix must obey certain conditions. Finally, lower bounds are found for the number of inequivalent Hadamard matrices
of order a power of 2, and consequently for the number of Hadamard-inequivalent Hadamard matrices of those orders. 相似文献