Ethephon increases rubber tree latex yield by regulating aquaporins and alleviating the tapping-induced local increase in latex total solid content

The concentration of phloem solute generally falls from leaves to roots. However, a local increase in latex total solid content (LILTSC) was identified near the tapping cut of rubber trees. To understand the mechanism of ethephon-stimulated latex yield, the formation and ethephon (an ethylene releaser) alleviation of the LILTSC near the tapping cut were examined. It was found that the LILTSC near the tapping cut of a tapped rubber tree was caused by the tapping-accelerated rubber biosynthesis which began following the first tapping and became significant after the fourth tapping. Ethephon stimulation markedly reduced the LILTSC. The latex yield change pattern upon ethephon stimulation was associated with the kinetic change of LILTSC and the decomposition dynamic of ethephon into ethylene. Once the LILTSC was reduced by ethylene release upon ethephon stimulation, the latex yield increased; however, when the ethylene release upon ethephon stimulation receded, the LILTSC was restored and the effect of ethephon stimulation dissipated. The reduction of LILTSC by ethephon stimulation could be ascribed to the translocation property of ethylene in plants and its regulation of aquaporins. Because maximum ethylene release upon tapping-cut-ethephon-application occured close to the tapping cut, the aquaporins were more up-regulated in this region, leading to a reduction of the LILTSC and an increase in latex yield. All these results suggest that the LILTSC near the tapping cut was caused by tapping; the ethephon-induced aquaporin up-regulation and LILTSC reduction are involved in the mechanism of ethephon-promoted latex yield.

Fabrication of core-shell structured natural rubber based microfibres for artificial blood vessel tissue engineering scaffolds

A successful trial on preparing natural rubber based core-shell structured fibres by co-axial electrospinning and fabrication of artificial blood vessel scaffolds from crosslinked fibres.

Slurry pump side-liner wear : comparison of some laboratory and field results

The current work compares some slurry pump lab wear results with the wear found across different field applications with d₈₅ particle size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for particles larger than d8The current work compares some slurry pump lab wear results with the wear found across different field applications with d₈₅ particle 10 size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different 11 material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle 12 size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are 13 also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab 14 tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for 15 particles larger than d₈₅ of about 700mm. © 2001 Elsevier Science B.Y. All rights reserved.

Hypoallergenic variants of the major latex allergen Hev b 6.01 retaining human T lymphocyte reactivity

Hev b 6.01 is a major allergen of natural rubber latex with sensitization of 70–86% of latex glove-allergic subjects. Recently, we mapped the immunodominant T cell sites of Hev b 6.01 to the highly IgE-reactive hevein (Hev b 6.02) domain. Hev b 6.01 contains 14 cysteine residues with multiple disulphide bridges stabilizing tertiary conformation. With the goal of a standardized specific immunotherapy we developed hypoallergenic Hev b 6.01 mutants by site-directed mutagenesis of selected cysteine residues (3, 12, 17, and 41) within the Hev b 6.02 domain. Peptides corresponding to the Hev b 6.02 domain of two of the mutants were also synthesized. These mutants and peptide variants showed markedly decreased or ablated latex-allergic patient serum IgE binding by immunoblotting and ELISA. Basophil activation testing confirmed markedly decreased activation with successive cysteine substitutions of the mutants and complete abrogation with the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide. Retention of T cell reactivity is crucial for effective specific immunotherapy and all mutants and peptide variants maintained their latex-specific T cell reactivity. The ablated allergenicity but retained T cell reactivity of the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide suggests this peptide is a suitable candidate for inclusion in a latex immunotherapy preparation.

Economic linkages across commodity futures : hedging and trading implications

We investigate cross-market trading dynamics in futures contracts written on seemingly unrelated commodities that are consumed by a common industry. On the Tokyo Commodity Exchange, we find such evidence in natural rubber (NR), palladium (PA) and gasoline (GA) futures markets. The automobile industry is responsible for more than 50% of global demand for each of these commodities. VAR estimation reveals short-run cross-market interaction between NR and GA, and from NR to PA. Cross-market influence exerted by PA is felt in longer dynamics, with PA volatility (volume) affecting NR (GA) volume (volatility). Our findings are robust to lag-specification, volatility measure, and consistent with full BEKK-GARCH estimation results. Further analysis, which benchmarks against silver futures market, TOCOM index and TOPIX transportation index, confirms that our results are driven by a common industry exposure, and not a commodity market factor. A simple trading rule that incorporates short-run GA and long-run PA dynamics to predict NR return yields positive economic profit. Our study offers new insights into how commodity and equity markets relate at an industry level, and implications for multi-commodity hedging.

Common industry exposure in seemingly unrelated commodities

We propose and document robust evidence of cross-market return, volatility, and volume interactions among futures contracts written seemingly unrelated commodities exposed to a common industry. On the Tokyo Commodity Exchange, we find such evidence in natural rubber (NR), aluminum (AL) and gasoline (GA) futures markets, which are complementary commodities heavily consumed by Japan's automobile industry. Our VAR results indicate that (i) for shorter dynamics, NR and GA volatility both influence AL volatility; GA volume affects NR volatility and volume; the GA market is immune to both NR and AL trading activities; (ii) for longer dynamics, AL volume affects both NR volume and GA volatility; NR volume influences GA volume. These results are robust to lag-specifications, volatility measures and are consistent with full BEKK-GARCH estimates. Further analysis using the silver contract, TOCOM and TOPIX transportation indices, shows that a commodity market factor cannot explain our result. Our results offer insights into how commodity and equity markets relate at an industry level.

Envisioning Indochina : the spatial and social ordering and imagining of a French colony

The emergence of Indochina in the French imagination was articulated in both representational and institutional modes. Representation involves the transmission of colonial ideals through more obtuse means; that is, through literary texts, travelogues, exhibitions, film and advertising. However, these textual sites feed from and invest in a material situation, which was the institutional arm of colonialism. Indochina was institutionally articulated in cartographic maps and surveys, in the new social spaces of cities and towns, in architectural and technological forms, through social technologies of discipline and welfare and in cultural and religious organisations. The aim of this thesis is to analyse, across a number of textual sites, the representation and institutionalisation of Otherness through the politics of space in the French colony of Indochina, Indochine in this sense becomes a spatial discourse. The French constructed a mental and physical space for Indochina by blanketing and suffocating the original cultural landscape, which in fact had to be ignored for this process to occur. What actually became manifest as a result of this projection stemmed from the French imagination. Just as the French manipulated space, language also underwent the same process of reduction. The Vietnamese script was latinised to make it more 'useable' and ‘accessible’. Through christening the union of Indochina; initiating a comprehensive writing reform; and renaming the streets in the colonial cities, the French used language us another tool for 'making transparent'. Furthermore, the colonial powers established a communication and transport network throughout the colony in an attempt to materialise their fictive (artificial) vision of a unified French Indochinese space. The accessibility and design of these different modes of transport reflected the gendered, racial and class divisions inherent in the colonial establishment. At the heart of representing and institutionalising Indochina was the desire to control and contain. This characterised French imperial ordering of space in the city and the rural areas. In rural areas land was divided into small parcels and alienated to individuals or worked into precise grids for the rubber plantation. In urban centres the native quarter was clearly demarcated from the European quarter which functioned as its modern, progressive Other. The rationale behind this segregation was premised on European, nineteenth century discourses of race, class, gender and hygiene. Influenced by Darwinian and neo-Lamarkian theories of race, this biological discourse identified the 'working class', 'women' and 'the native' as not only biologically but also culturally inferior. They were perceived as a potential, degenerative threat to the biological, cultural and industrial development of the nation. In the colonial context, space was thus ordered and domesticated to control the native population. Coextensively, the literature which springs from such a structure will be tainted by the same ideas, and thus the spaces it formulates within the readers mind feed on and reinforce this foundation. Examples of gender and indigenous narratives which contest this imaginative, transparent topography are analysed throughout this thesis. They provide instances of struggle and resistance which undermine the ideal/stereotypical level of architectural and planned space and delineate an alternative insight into colonial spatial and social relations. The fictional accounts of European women and indigenous writers both challenge and reaffirm the fixity of some of these idealised colonial boundaries. In various literary, historical, political, architectural and cinematic discourses Indochina has been und continues to be depicted as a modern city and exotic Utopia. Informed by the mood of nostalgia, exotic images of Indochina have resurfaced in contemporary French culture. France's continued desire to create, control and maintain an Indochinese space in the French public imagination reinforces the multi-layered, interconnected and persistent nature of colonial discourse.

Characterization of the moisture absorption and thermal ageing behaviour of polymeric composite systems using Raman spectroscopy

Advanced polymeric materials and their respective composites are fast becoming one of the world's most frequently used engineering materials. They find application in the manufacture of e.g. boat hulls, high performance motor vehicles, aircraft components and sports goods. Their high specific strength and specific stiffness give them the edge in applications where weight savings are critical, but their long-term durability is often questioned. These materials are susceptible to environmental conditions such as temperature and humidity. There is also a lack of relevant data, due to the long time-scales required for testing. In this study, the Raman technique has been used to monitor the degradation of two composite systems, namely: a rubber toughened vinylester material used in the marine industry and a high temperature bismaleimide/carbon fibre aerospace composite. Preliminary Raman studies show that the toughening rubber particles dispersed in the cured vinylester resin are leached out during hygrothermal ageing. The weight gain during ageing suggests that this leaching process occurs concurrently with the absorption of water molecules. An increase in the degree of cross-linking is observed when bismaleimide/carbon fibre composite is aged at high temperature. This cross- linking tendency decreases with increasing depth within the carbon fibre bundle.

Structure-property relationships of nylon 6, MXD6, their blends and nanocomposites

This research project aimed to develop an understanding of the structure-property relationships of nanocomposite materials (injection moulded and fibres) based on nylon 6, MXD6 and their blends, with a layered silicate in combination with polyhedral oligomeric silsesquioxane nanoparticles and SEBS rubber particles.

Dielectric properties of conducting polymer

The dielectric properties of conducting polymer composites containing polypyrrole (PPy) crushed films, PPy powder, polyaniline (PAn) base and acid powders as the dispersants and silicone rubber and vinyl ester as matrix materials have been investigated in the frequency range 2-18 GHz. The dielectric parameters such as the real part, epsiprime, and imaginary part, epsiPrime, of the permittivity and loss tangent, tandelta, increase with increasing conductivity and concentration of the dispersant. The geometrical shape of the dispersant governs the ability of conductive network formation which is indicated by a large drop in the resistivity of the composite. Also, dispersant/matrix interactions and physical properties of the matrix influence the agglomeration of the dispersant phase which, in turn, affects the dielectric properties of the composites. Flakes of PPy obtained by crushing highly conductive films and large PAn powder aggregates were unable to form a conducting network. The composites without a network of dispersant exhibit low dielectric parameters. On the other hand, high values of tan delta ranging from 0.7–1.1 were achieved for the PPy powder (15 parts)/silicone rubber composites where a conducting network was observed.

Comparing different economic linkages among commodity futures

Gasoline (GA) and kerosene (KO) are extracted from crude oil (CO), such that the three fuel commodities share a chemical link. On the other hand, GA also shares an industrial link with natural rubber (NR) and palladium (PA) as complementary commodities that are heavily consumed by the automobile industry. We contrast the information content embedded in the two economic linkages. Focusing on TOCOM futures contracts written on the five commodities and centering on GA, we confirm that incremental information provided by either CO, KO or NR, PA over a buy-and-hold strategy and a naive forecast, are both statistically and economically significant. While the chemical link forecast is more profitable, a double-link forecast generated from a VECM with two cointegrating vectors (KO-GA and GANR prices) outperforms both single-link forecasts based on risk-adjusted profit net of transaction costs. Further comparisons against the profitability of commodity-based momentum strategies documented in Erb and Harvey (2006) and Miffre and Rallis (2007) show that the double-link forecast holds its own against the most profitable of the 75 momentum strategies considered. This strongly suggests that not only are there incremental profits to be gained from harnessing and combining economic links among commodity futures, the resultant incremental profits are economically significant against other proven commodity-based trading strategies in the existing literature.

The effects of testing procedure on critical fall height determination for third-generation synthetic turf

Test procedures and their accuracy in determining critical fall height (CFH) on sporting grounds are paramount to player safety. The procedure currently adopted for synthetic turf in Australian football [1] consists of four consecutive drops at various drop heights at three test locations on the sample. The quantity and packing of the infill in third-generation turf and the pooling effect of the rubber particles with consecutive drops suggests that the current standard protocol may need re-assessment. Therefore, the purpose of this pilot study was to investigate whether current methods of testing for CFH are appropriate for third-generation synthetic turf or whether an alternative or adapted method needs to be developed. CFH was measured, using a HISUN Uniaxe-II Impact Tester, on 12 combinations of synthetic turf samples (four different products with three shock pad options). Three conditions were investigated on each sample; the existing protocol; an alternative 12 single-drop protocol and four single drops from the CFH determined from the existing protocol. A significant difference was found for both absolute and percentage difference between the existing and 12 single-drop protocol, with p = 0.001 and t = 4.33 and p < 0.001 and t = 6.03, respectively. There was also a significant difference between the CFH reached with and without a shock pad for both the existing protocol and the 12 single-drop protocol. The results of this pilot study demonstrate that differences do occur with alterations to the existing protocol and highlight the need for a more detailed characterisation of testing methods on third-generation synthetic turf and the response of surfaces to them.

The science of our own fiction : affective experiments enacted through creative research

This paper will explore the ways in which art may be understood as an ongoing experiment that interacts with the plasticity of the body to prompt change and affect the body-environment relationship. The arts offer an approach to research that recognizes the importance of the affect in studies of perception and action, self-organization and selection. An affective approach to experimentation would connect cognitive activity to the material processes of the environment in a science of our own fiction. This connection becomes the basis of affective experiments, which aim to yield new insights by merging the creative researcher with self-affecting-experimenter. To this end, I will discuss the scientific objectives of the “rubber hand”, and the ‘mirror-box” experiments are contrasted with work by artists-turned-architects Arakawa and Gins and three of my creative projects to suggest how creative research might enact embodied change. Throughout the paper I will argue that cognitive processes such as attention, selection, decision and judgment are ripe for re-entry and experimentation through an embodied approach to acquiring knowledge that is particular to the arts.

Primary prevention of latex related sensitisation and occupational asthma : a systematic review

Eight primary prevention intervention studies on natural rubber latex (NRL) published since 1990 were identified and reviewed. This is the largest evidence base of primary prevention studies for any occupational asthmagen. Review of this small and largely observational evidence base supports the following evidence statement: Substitution of powdered latex gloves with low protein powder‐free NRL gloves or latex‐free gloves greatly reduces NRL aeroallergens, NRL sensitisation, and NRL‐asthma in healthcare workers. Evidence in support of this statement is ranked SIGN level 2+, referring to well conducted case‐control or cohort studies with a low risk of confounding, bias, or chance and a moderate probability that the relationship is causal. Substitution of powdered latex gloves with low protein powder‐free NRL gloves or latex‐free gloves promises benefits to both workers' health and cost and human resource savings for employers. This message should be broadly disseminated beyond the hospital sector to include other healthcare settings (such as aged care facilities) as well as food service and other industries where latex gloves might be used.

Carbon nanotube based elastomer composites-an approach towards multifunctional materials

The current study focuses on giving a basic understanding of tubular graphene sheets or carbon nanotubes (CNTs) and points towards their role in fabricating elastomer composites. Since the properties and the performance of CNT reinforced elastomer composites predominantly depend on the rate of dispersion of fillers in the matrix, the physical and chemical interaction of polymer chains with the nanotubes, crosslinking chemistry of rubbers and the orientation of the tubes within the matrix, here, a thorough study of these topics is carried out. For this, various techniques of composite manufacturing such as pulverization, heterocoagulation, freeze drying, etc. are discussed by emphasizing the dispersion and alignment of CNTs in elastomers. The importance of the functionalization technique as well as the confinement effect of nanotubes in elastomer media is derived. In a word, this article is aimed exclusively at addressing the prevailing problems related to the CNT dispersion in various rubber matrices, the solutions to produce advanced high-performance elastomeric composites and various fields of applications of such composites, especially electronics. Special attention has also been given to the non-linear viscoelasticity effects of elastomers such as the Payne effect, Mullin's effect and hysteresis in regulating the composite properties. Moreover, the current challenges and opportunities for efficiently translating the extraordinary electrical properties of CNTs to rubbery matrices are also dealt with.