Driving selective aerobic oxidation of alkyl aromatics by sunlight on alcohol grafted metal hydroxides

It is very difficult to selectively oxidise stable compounds such as toluene and xylenes to useful chemicals with molecular oxygen (O 2) under moderate conditions. To achieve high conversion and less over-oxidised products, a new class of photocatalysts, metal hydroxide nanoparticles grafted with alcohols, is devised. They can efficiently oxidise alkyl aromatic compounds with O 2 using visible or ultraviolet light or even sunlight to generate the corresponding aldehydes, alcohols and acids at ambient temperatures and give very little over-oxidation. For example toluene can be oxidised with a 23% conversion after a 48-hour exposure to sunlight with 85% of the product being benzaldehyde, and only a trace of CO 2.The surface complexes grafted onto metal hydroxides can absorb light, generating free radicals on the surface, which then initiate aerobic oxidation of the stable alkyl aromatic molecules with high product selectivity. This mechanism is distinctly different from those of any known catalysts. The use of the new photocatalysts as a controlled means to generate surface radicals through light excitation allows us to drive the production of fine organic chemicals at ambient temperatures with sunlight. The process with the new photocatalysts is especially valuable for temperature-sensitive syntheses and a greener process than many conventional thermal reactions. © 2012 The Royal Society of Chemistry.

Effects of lime content and amelioration period in double lime application on the strength of lime treated expansive sub-grade soils

The addition of lime into soils has been widely used to stabilize the expansive sub-grade soils when the road pavements are constructed on them. It is common practice to apply a half of the required lime amount and allow a certain time period for lime to react with soils (Amelioration period) before applying the rest of lime and compacting the sub-grade. The optimum amelioration period is essential to minimize the construction delay and to gain the higher strength. In this study, two different expansive soils procured from two different locations in the state of Queensland in Australia were first mixed with different lime contents. A soil mixed with a particular lime content was compacted at different amelioration periods (e.g.: 0, 6, 12, 18, 24 hrs) to obtain soil samples to measure the Unconfined Compressive Strength (UCS). The results suggested that for a given amelioration period, UCS increased with the increase in lime content. The optimum amelioration period could be within 14~17 hours for most of the lime contents in tested soils. This could suggest that the current 24-48 hour amelioration period specified by the Queensland Department of Transport and Main roads could be reduced.

Exo1 plays a major role in DNA end resection in humans and influences double-strand break repair and damage signaling decisions

The resection of DNA double-strand breaks (DSBs) to generate ssDNA tails is a pivotal event in the cellular response to these breaks. In the two-step model of resection, primarily elucidated in yeast, initial resection by Mre11-CtIP is followed by extensive resection by two distinct pathways involving Exo1 or BLM/WRN-Dna2. However, resection pathways and their exact contributions in humans in vivo are not as clearly worked out as in yeast. Here, we examined the contribution of Exo1 to DNA end resection in humans in vivo in response to ionizing radiation (IR) and its relationship with other resection pathways (Mre11-CtIP or BLM/WRN). We find that Exo1 plays a predominant role in resection in human cells along with an alternate pathway dependent on WRN. While Mre11 and CtIP stimulate resection in human cells, they are not absolutely required for this process and Exo1 can function in resection even in the absence of Mre11-CtIP. Interestingly, the recruitment of Exo1 to DNA breaks appears to be inhibited by the NHEJ protein Ku80, and the higher level of resection that occurs upon siRNA-mediated depletion of Ku80 is dependent on Exo1. In addition, Exo1 may be regulated by 53BP1 and Brca1, and the restoration of resection in BRCA1-deficient cells upon depletion of 53BP1 is dependent on Exo1. Finally, we find that Exo1-mediated resection facilitates a transition from ATM- to ATR-mediated cell cycle checkpoint signaling. Our results identify Exo1 as a key mediator of DNA end resection and DSB repair and damage signaling decisions in human cells.

Double blind : women as creative practice-led researchers

While the productive relationship between praxis and feminist research has been well established, the situation is more complicated for female artist/researchers in the fraught field of creative practice-led research. Firstly, their research is being conducted in the context of ongoing debate, as Andrea Phillips has summarized, over whether practice-led research has been embraced in order to potentially produce emancipatory knowledge, or whether it is simply the rationalization and quantification of creative processes. Secondly, there is a pervasive paradox whereby, rather than feeling empowered by the process of critical and reflective self-analysis, many women are inhibited by enduring insecurities about the value of their work and/or their ownership of it. The reasons for this appear to be twofold: they are disheartened by the ongoing disproportion of successful women artists, and they are intimidated by the fundamentally masculine discourse surrounding research in the university. Many of these anxieties appear to have been exacerbated by the research quality assessment process, the Excellence in Research for Australia Initiative (ERA). This collaborative paper draws on the authors' experiences as both artist-researchers and educators to contextualize this paradox and also discuss what forms of praxis intervention may be useful in the preparation for, and supervision of, creative practice-led research by women.

The role of randomly mixed-layered chlorite/smectite in the transformation of smectite to chlorite

Vesicular and groundmass phyllosilicates in a hydrothermally altered basalt from the Point Sal ophiolite, California, have been studied using transmission electron microscopy (TEM). Pore-filling phyllosilicates are texturally characterized as having coherent, relatively thick and defect-free crystals of chlorite (14 Å) with occasional 24-Å periodicities. Groundmass phyllosilicates are texturally characterized as 1) randomly oriented crystals up to 200 Å in width and 2) larger, more coherent crystals up to 1000 Å in width. Small crystallites contain predominantly 14-Å layers with some 24-Å units. Large crystals show randomly interlayered chlorite/smectite (C/S), with approximately 50% chlorite on average. Adjacent smectite-like layers are not uncommon in the groundmass phyllosilicates. Electron microprobe analyses show that Fe/Mg ratios of both groundmass and vesicular phyllosilicates are fairly constant. Termination of brucite-like interlayers has been identified in some of the TEM images. The transformation mechanisms represented by these layer terminations are 1) growth of a brucite-like interlayer within smectite interlayer regions and 2) the dissolution and reprecipitation of elements to form chlorite layers. Both mechanisms require an increase in volume as smectite transforms to chlorite. The data, combined with that from previously published reports, suggest that randomly interlayered C/S is a metastable phase formed in microenvironments with low water/rock ratios. Chlorite forms in microenvironments in the same sample dominated by higher water/rock ratios. The relatively constant number of Mg's in the structure (Mg#) of both structures indicates that in both microenvironments the bulk rock composition has influence over the composition of phyllosilicates.

Soil-pile interaction in deep layered marine sediment under seismic excitation

Under seismic loads neither the response of the pile nor the response of ground are independent of each other, contrary what is normally assumed. In seismic design of buildings, dynamic response of a structure is determined by assuming a fixed base on sub-grade and neglecting the physical interaction between foundation and soil profile in which it is embedded. However, the seismic response of pile foundations in vibration sensitive soil profiles is significantly affected by the behaviour of supporting soil. This research uses validated Finite Element techniques to simulate the seismic behaviour of pile foundations embedded in multilayered vibration sensitive soils.

Layered silicates in Chondritic Porous Aggregate W7029*A : a case of primary growth

An important subset of extraterrestrial particles that reach the Earth's stratosphere include the so-called Chondritic Porous Aggregates (CPA's) [1-3]. In general, CPA's have a fluffy morphology and consist of numerous (>104)subparticles that are often <100A in size [4]. Mineral species in CPA's include Mg-rich pyroxene and olivine, Fe- and (Fe,Ni)-sulphides, taenite, Fe,Ni-carbides, magnetite, Ti-metal, a Bi-phase (metal or oxide), and variable amounts of carbonaceous material [1, 5-7]. Hydrated silicates are rare in CPA's and are limited to aggregates that have not been severely altered (thermo-metamorphosed) during atmospheric entry [8]. The presence of hydrated silicates in one cosmic dust particle was established by X-ray diffraction [2] and has been inferred in others by infra-red spectroscopy [8]. If CPA's are cometary, their mineralogy and morphology suggest that at least two episodes of aggregation occurred and that variations in porosity may be related to local differences in ice-to-dust ratio [3].

Chromatin modifications involved in the DNA damage response to double strand breaks

In eukaryotes, genomic DNA is tightly compacted into a protein-DNA complex known as chromatin. This dense structure presents a barrier to DNA-dependent processes including transcription, replication and DNA repair. The repressive structure of chromatin is overcome by ATP-dependent chromatin remodelling complexes and chromatin-modifying enzymes. There is now ample evidence that DNA double-strand breaks (DSBs) elicit various histone modifications (such as acetylation, deacetylation, and phosphorylation) that function combinatorially to control the dynamic structure of the chromatin microenvironment. The role of these mechanisms during transcription and replication has been well studied, while the research into their impact on regulation of DNA damage response is rapidly gaining momentum. How chromatin structure is remodeled in response to DNA damage and how such alterations influence DSB repair are currently significant questions. This review will summarise the major chromatin modifications and chromatin remodelling complexes implicated in the DNA damage response to DSBs.

A multi-layered approach for site detection in UAS emergency landing scenarios using geometry-based image segmentation

This paper presents an alternative approach to image segmentation by using the spatial distribution of edge pixels as opposed to pixel intensities. The segmentation is achieved by a multi-layered approach and is intended to find suitable landing areas for an aircraft emergency landing. We combine standard techniques (edge detectors) with novel developed algorithms (line expansion and geometry test) to design an original segmentation algorithm. Our approach removes the dependency on environmental factors that traditionally influence lighting conditions, which in turn have negative impact on pixel-based segmentation techniques. We present test outcomes on realistic visual data collected from an aircraft, reporting on preliminary feedback about the performance of the detection. We demonstrate consistent performances over 97% detection rate.

Half metallicity in a zigzag double-walled nanotube nanodot : an Ab initio prediction

Ab initio density functional calculations were performed to study finite-length zigzag (7, 0) @ (16, 0) double-walled carbon nanotubes (DWCNTs) with H-termination at the open ends. We find that such a DWCNT nanodot displays a very large magnetic moment at the zigzag edges and the ground state displays symmetric anti-ferromagnetic coupling. When an external electric field is applied along the direction of tube axis, a gap is opened for one spin channel, whereas another spin channel remains metallic, i.e. half metallicity occurs. Our results suggest an important new avenue for the development of CNT-based spintronic materials with enhanced properties.

Community response to disasters in Indonesia : Gotong Royong; a double edged-sword

Indonesia is a country spread across wide-ranging archipelago, located in South East Asia between two oceans, the Indian and the Pacific. Indonesia is well known as an active tectonic region because it lies on top of three major active tectonic plates: the Eurasian in the North, the Indian Ocean-Australian in the South, and the Pacific plate in the East. The southern and eastern part of the country features a range of volcanic arcs, volcanic mountains, and lowlands with 500 young volcanoes, of which 128 are active and thus representing 15% of the world’s active volcanoes. In the period 2002-2007, approximately 1782 disasters occurred, with hundreds of thousands of lives lost and billions of rupiah in losses incurred: (Floods - 1183 instances, cyclones - 272 instances, and landslides - 252 instances). Of these, the 2004 Aceh tsunami and the 2006 central Java earthquake (impacting predominantly city and suburbs of Yogyakarta) were the most significant. Even so, disaster management experts believe lessons learnt from the two major natural disasters needs to be formalised into laws and institutions before another disaster occurs, regardless of the type of natural disaster – i.e. Volcano eruption or landslide; as opposed to tsunami or earthquake. Following in the wake of disasters occurring in Yogyakarta, many of its community members responded by banding together as one, with the determination of rebuilding its villages and cities through the spirit of ‘gotong royong’. The idea of social interaction; in particular as a collective, consensual, and cooperative nation; has predominantly formed the ideological basis of Indonesia’s societal nature. Many Indonesian terms cohere to this ideology, such as: ‘koperasi” (cooperatives as the basis of economic interactions), ‘musyawarah’ (consensual nature in decision making), and ‘gotong royong’ (mutual assistance). ‘Gotong royong’ has become a key cultural operator in Indonesia, in particular In Jogjakarta. Appropriately so as ‘gotong royong’ is depicted from the traditional Javanese village, where labour is accomplished through reciprocal exchange and the villagers are motivated by a general ethos of selfishness and concern for the common good. The culture of ‘gotong royong’ promotes positive values such as social harmony and mutual reciprocation in disaster-affected areas provides the necessary spirit needed to endure the hardships and for all involved. While gotong royong emphasises the positive notions of mutual family support and deep community level activity there is a potential for contrast against government lead disaster response and recovery management activities especially in settings where sporadic governance mechanisms exist and transparency and accountability in the recovery process of public infrastructure assets have been questioned. This paper thus questions whether Gotong Royong is a double-edged sword, and explores the potential marriage of community values and governance mechanisms for future disaster management planning and practice.

Double tax agreements and the international allocation of business income in Australia

Increasingly, the effectiveness of the present system of taxation of international businesses is being questioned. The problem associated with the taxation of such businesses is twofold. A system of international taxation must be a fair and equitable system, distributing profits between the relevant jurisdictions and, in doing so, avoiding double taxation. At the same time, the prevention of fiscal evasion must be secured. In an attempt to achieve a fair and equitable system Australia adopts unilateral, bilateral and multilateral measures to avoid double taxation and restrict the avoidance of tax. The first step in ascertaining the international allocation of business income is to consider the taxation of business income according to domestic law, that is, the unilateral measures. The treatment of international business income under the Australian domestic law, that is, the Income Tax Assessment Act 1936 (Cth) and Income Tax Assessment Act 1997 (Cth), will depend on two concepts, first, whether the taxpayer is a resident of Australia and secondly, whether the income is sourced in Australia. After the taxation of business profits has been determined according to domestic law it is necessary to consider the applicability of the bilateral measures, that is, the Double Tax Agreements (DTAs) to which Australia is a party, as the DTAs will override the domestic law where there is any conflict. Australia is a party to 40 DTAs with another seven presently being negotiated. The preamble to Australia's DTAs provides that the purpose of such agreements is 'to conclude an Agreement for the avoidance of double taxation and the prevention of fiscal evasion with respect to taxes on income'. Both purposes, for different reasons, are equally important. It has been said that: The taxpayer hopes the treaty will prevent the double taxation of his income; the tax gatherer hopes the treaty will prevent fiscal evasion; and the politician just hopes. The first purpose, the avoidance of double taxation, is achieved through the provision of rules whereby the Contracting States agree to the classification of income and the allocation of that income to a particular State. In this sense DTAs do not allocate jurisdiction to tax but rather provide an arrangement whereby the States agree to restrict their substantive law. The restriction is either through the non-taxing of the income or via the provision of a tax credit.

Modelling the failure of thin layered mortar joints in masonry

This paper deals with the failure of high adhesive, low compressive strength, thin layered polymer mortar joints in masonry through a contact modelling in finite element framework. Failure due to combined shear, tensile and compressive stresses are considered through a constitutive damaging contact model that incorporates traction–separation as a function of displacement discontinuity. The modelling method is verified using single and multiple contact analyses of thin mortar layered masonry specimens under shear, tensile and compressive stresses and their combinations. Using this verified method, the failure of thin mortar layered masonry under a range of shear to tension ratios and shear to compression ratios has been examined. Finally, this model is applied to thin bed masonry wallettes for their behaviour under biaxial tension–tension and compression–tension loadings perpendicular and parallel to the bed joints.