Double trouble — the art of synthesis of chiral dimeric natural products

Double or nothing! Recently the total ynthesis of secalonic acids A and D was reported. This work and other natural product syntheses with a dimerization step as a common feature are featured in this highlight. The significant biological activity of the secalonic acids and the fact that their synthesis has fascinated synthetic chemists for the past forty years make this work a milestone in natural product synthesis.

Isolation and characterization of charge-tagged phenylperoxyl radicals in the gas phase : direct evidence for products and pathways in low temperature benzene oxidation

The phenylperoxyl radical has long been accepted as a critical intermediate in the oxidation of benzene and an archetype for arylperoxyl radicals in combustion and atmospheric chemistry. Despite being central to many contemporary mechanisms underpinning these chemistries, reports of the direct detection or isolation of phenylperoxyl radicals are rare and there is little experimental evidence connecting this intermediate with expected product channels. We have prepared and isolated two charge-tagged phenyl radical models in the gas phase [i.e., 4-(N,N,N-trimethylammonium) phenyl radical cation and 4-carboxylatophenyl radical anion] and observed their reactions with dioxygen by ion-trap mass spectrometry. Measured reaction rates show good agreement with prior reports for the neutral system (k(2)[(Me3N+)C6H4 center dot + O-2] = 2.8 x 10(-11) cm(3) molecule(-1) s(-1), Phi = 4.9%; k(2)[(-O2C)C6H4 center dot + O-2] = 5.4 x 10(-1)1 cm(3) molecule(-1) s(-1), Phi = 9.2%) and the resulting mass spectra provide unequivocal evidence for the formation of phenylperoxyl radicals. Collisional activation of isolated phenylperoxyl radicals reveals unimolecular decomposition by three pathways: (i) loss of dioxygen to reform the initial phenyl radical; (ii) loss of atomic oxygen yielding a phenoxyl radical; and (iii) ejection of the formyl radical to give cyclopentadienone. Stable isotope labeling confirms these assignments. Quantum chemical calculations for both charge-tagged and neutral phenylperoxyl radicals confirm that loss of formyl radical is accessible both thermodynamically and entropically and competitive with direct loss of both hydrogen atom and carbon dioxide.

Direct detection of additives and degradation products from polymers by liquid extraction surface analysis employing chip-based nanospray mass spectrometry

RATIONALE: Polymer-based surface coatings in outdoor applications experience accelerated degradation due to exposure to solar radiation, oxygen and atmospheric pollutants. These deleterious agents cause undesirable changes to the aesthetic and mechanical properties of the polymer, reducing its lifetime. The use of antioxidants such as hindered amine light stabilisers (HALS) retards these degradative processes; however, mechanisms for HALS action and polymer degradation are poorly understood. METHODS: Detection of the HALS TINUVINW123 (bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate) and the polymer degradation products directly from a polyester-based coil coating was achieved by liquid extraction surface analysis (LESA) coupled to a triple quadrupole QTRAPW 5500 mass spectrometer. The detection of TINUVINW123 and melamine was confirmed by the characteristic fragmentation pattern observed in LESA-MS/MS spectra that was identical to that reported for authentic samples. RESULTS: Analysis of an unstabilised coil coating by LESA-MS after exposure to 4 years of outdoor field testing revealed the presence of melamine (1,3,5-triazine-2,4,6-triamine) as a polymer degradation product at elevated levels. Changes to the physical appearance of the coil coating, including powder-like deposits on the coating's surface, were observed to coincide with melamine deposits and are indicative of the phenomenon known as polymer ' blooming'. CONCLUSIONS: For the first time, in situ detection of analytes from a thermoset polymer coating was accomplished without any sample preparation, providing advantages over traditional extraction-analysis approaches and some contemporary ambient MS methods. Detection of HALS and polymer degradation products such as melamine provides insight into the mechanisms by which degradation occurs and suggests LESA-MS is a powerful new tool for polymer analysis. Copyright (C) 2012 John Wiley & Sons, Ltd.

Wasting Time? Art, Science and New Experience. Examining the Artwork, Know more (House of Commons)

Today the future is travelling rapidly towards us, shaped by all that which we have historically thrown into it. Much of what we have designed for our world over the ages, and much of what we continue to embrace in the pursuit of mainstream economic, cultural and social imperatives, embodies unacknowledged ‘time debts’. Every decision we make today has the potential to ‘give time to’, or take ‘time away’ from that future. This idea that ‘everything‘ inherently embodies ‘future time left’ is underlined by design futurist Tony Fry when he describes how we so often ‘waste’ or ‘take away’ ‘future time’. “In our endeavours to sustain ourselves in the short term we collectively act in destructive ways towards the very things we and all other beings fundamentally depend upon”

Women on the Heritage Register : the case of Nellie McCredie and Uanda House

Uanda house is of historical importance to Queensland both in terms of its architectural design and its social history. Uanda is a low set, single story house built in 1928, located in the inner city Brisbane suburb of Wilston. Architecturally, the house has a number of features that distinguish it from the surrounding bungalow influenced inter-war houses. The house has been described as a Queensland style house with neo-Georgian influences. Historically, it is associated with the entry of women into the profession of architecture in Queensland. Uanda is the only remaining intact work of architect/draftswoman Nellie McCredie and one of a very few examples of works by pioneering women architects in Queensland. The house was entered into the Queensland Heritage Register, in 2000, after an appeal against Brisbane City Council’s refusal of an application to demolish the house was disputed in the Queensland Planning and Environment court in 1998/1999. In the court’s report, Judge Robin QC, DCJ, stated that, “The importance of preserving women's history and heritage, often previously marginalised or lost, is now accepted at government level, recognising that role models are vital for bringing new generations of women into the professions and public life.” While acknowledging women’s contribution to the profession of architecture is an important endeavour, it also has the potential to isolate women architects as separate to a mainstream history of architecture. As Julie Willis writes, it can imply an atypical, feminine style of architecture. What is the impact or potential implications of recognising heritage buildings designed by women architects? The Judge also highlights the absence of a recorded history of unique Brisbane houses and questions the authority of the heritage register. This research looks at these points of difference through a case study of the Uanda house. The paper will investigate the processes of adding the house to the heritage register, the court case and existing research on Nellie McCredie and Uanda House.

Minimization of bauxite residue neutralization products using nanofiltered seawater

Currently, open circuit Bayer refineries pump seawater directly into their operations to neutralize the caustic fraction of the Bayer residue. The resulting supernatant has a reduced pH and is pumped back to the marine environment. This investigation has assessed modified seawater sources generated from nanofiltration processes to compare their relative capacities to neutralize bauxite residues. An assessment of the chemical stability of the neutralization products, neutralization efficiency, discharge water quality, bauxite residue composition, and associated economic benefits have been considered to determine the most preferable seawater filtration process based on implementation costs, savings to operations and environmental benefits. The mechanism of neutralization for each technology was determined to be predominately due to the formation of Bayer hydrotalcite and calcium carbonate, however variations in neutralization capacity and efficiencies have been observed. The neutralization efficiency of each feed source has been found to be dependent on the concentration of magnesium, aluminium, calcium and carbonate. Nanofiltered seawater with approximately double the amount of magnesium and calcium required half the volume of seawater to achieve the same degree of neutralization. These studies have revealed that multiple neutralization steps occur throughout the process using characterization techniques such as X-ray diffraction (XRD), infrared (IR) spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES).

Secreted products and extracellular matrix from testicular peritubular myoid cells influence androgen-binding protein secretion by Sertoli cells in culture

Metabolic cooperation mediated by secreted factors between Sertoli cells and peritubular myoid cells has been well documented. We have confirmed that factors secreted by peritubular myoid cells modulate androgen-binding protein (ABP) secretion by Sertoli cells and shown further that this can also be achieved with peritubular myoid cell extracellular matrix (ECM). While peritubular myoid cell ECM potentiated the stimulatory effect of dibutyryl cyclic AMP on Sertoli cell ABP secretion, secreted factors did not, suggesting that the two components influence Sertoli cells through distinct mechanisms. We also tested other factors and other cell lines for effects on ABP production by Sertoli cells. The addition of human plasma fibronectin or conditioned medium from the basement membrane-producing Englebreth-Holm- Swarm sarcoma also stimulated ABP secretion by Sertoli cells. Cocultures of epithelial Sertoli cells with the cells of mesenchymal origin, such as testicular peritubular myoid cells, embryonic skin fibroblasts, and bladder smooth muscle cells, significantly stimulated ABP secretion by Sertoli cells, but co-culture with the epithelial-derived Martin-Darby canine kidney cell line had no effect on Sertoli cell-secreted ABP levels. Our data further define the epithelial-mesenchymal cell interaction that exists between Sertoli cells and peritubular myoid cells in the mammalian testis.

Measuring the preference for dwelling characteristics of Melbourne : railway stations and house prices

The relationship between public transportation and home values has proven to be complex, with studies providing divergent findings. Using Victorian Valuer General Data for 2009, this paper applies a hedonic pricing approach to the Melbourne metropolitan housing market in order to estimate the impacts of proximity to a train station on residential property prices. The findings reveal a negative impact on dwelling price for those properties within 125 metres from a train station and a positive relationship between dwelling price and proximity for properties more than 125 metres away.

Revisiting the adoption of innovative products on Australian road infrastructure projects

Construction product innovation can exert a positive influence on project and industry performance. However, guidance is scarce on product innovation diffusion for road infrastructure, in contrast to the large body of literature on the manufacturing industry. A conceptual framework is proposed to understand these processes. Advice is given to managers based on the framework and a large quantitative survey. The framework focuses on contextual characteristics that influence the decision to adopt new-to-industry product innovation, as part of a diffusion process. Case study data are interpreted within the revised framework to test its value and disaggregate the broad obstacles to innovation. A large quantitative survey was then conducted to rank the relative importance of the obstacles constraining the adoption of innovative products on road construction projects. The three most important obstacles were found to be: (1) overemphasis on up-front project costs during tender stage; (2) disagreement over who carries the risk of new product failure; and (3) adversarial contract relations. The results suggest refinements to the conceptual framework to make it a more powerful tool for categorizing and analysing construction innovation obstacles. Results also suggest well-resourced repeat interactions within complementary procurement and regulatory systems will enhance the project teams’ ability to recognize and address innovation obstacles. Further, improved relationships are expected to decrease the need for an overly conservative approach to product approval and prescriptive specifications.

Synthesis, characterization and comparative OFET behaviour of indenofluorene-bithiophene and terthiophene alternating copolymers

The synthesis of alternating copolymers of tetraalkylindenofluorene with bithiophene and terthiophene using Suzuki polycondensation route is reported. We report on the optical and electrochemical properties of these copolymers. AFM analysis of the microscopic morphology of thin deposits showed that the copolymer with terthiophene units produced the more ordered films, with well-defined fibrillar structures, resulting from highly-regular dense packing due to strong π-π interchain interactions, in contrast to the amorphous bithiophene copolymer. Upon testing these materials in FETs the terthienyl copolymers displayed the higher charge mobilities among the studied compounds, with values of over 10-4 cm2 V-1 s-1 being obtained.

Demand for refilled reusable products

The conversion of one-way polyethylene terephthalate (PET) bottles into reusable bottles helps reduce environmental burden. Recently, the Ministry of the Environment in Japan began discussing the introduction of reusable bottles. One of the barriers to introducing the new type of bottle is consumer unwillingness to accept refilled reusable bottles. We administered the questionnaires to consumers in a pilot test on reusable PET bottles organized to analyze the demand for these products. To increase the demand for refilled reusable bottles, it is necessary to supply refilled reusable bottles that are acceptable to consumers who are concerned about container flaws and stains.

Greenhouse gas emissions from sub-tropical agricultural soils after addition of organic by-products

As the cost of mineral fertilisers increases globally, organic soil amendments (OAs) from agricultural sources are increasingly being used as substitutes for nitrogen. However, the impact of OAs on the production of greenhouse gases (CO2 and N2O) is not well understood. A 60-day laboratory incubation experiment was conducted to investigate the impacts of applying OAs (equivalent to 296 kg N ha−1 on average) on N2O and CO2 emissions and soil properties of clay and sandy loam soils from sugar cane production. The experiment included 6 treatments, one being an un-amended (UN) control with addition of five OAs being raw mill mud (MM), composted mill mud (CM), high N compost (HC), rice husk biochar (RB), and raw mill mud plus rice husk biochar (MB). These OAs were incubated at 60, 75 and 90% water-filled pore space (WFPS) at 25°C with urea (equivalent to 200 kg N ha−1) added to the soils thirty days after the incubation commenced. Results showed WFPS did not influence CO2 emissions over the 60 days but the magnitude of emissions as a proportion of C applied was RB < CM < MB < HC

Impacts of introduced aquaculture species on markets for native marine aquaculture products : the case of edible oysters in Australia

Economic competition between introduced and native aquaculture species is of interest for industry stakeholders since increased production can affect price formation if both aquaculture species are part of the same market or even substitutes. In this study, we focus on the Australian edible oyster industry, which is dominated by two major species—the native Sydney rock oyster (grown mainly in Queensland and New South Wales) and the non-native Pacific oyster (grown mainly in South Australia and Tasmania). We examine the integration of the Australian oyster market to determine if there exists a single or several markets. Short- and long-run own, cross-price and income flexibilities of demand are estimated for both species using an inverse demand system of equations. The results suggest that the markets for the two species are integrated. We found evidence that the development of the Pacific oyster industry has had an adverse impact on Sydney rock oyster prices. However, our results show that both species are not perfect substitutes. Demand for Sydney rock oysters is relatively inelastic in the long run, yet no long-run relationships can be identified for Pacific oysters, reflecting the developing nature of this sector.