Automated solid phase synthesis of oligoarabinofuranosides

Automated solid phase synthesis enables rapid access to the linear and branched arabinofuranoside oligosaccharides. A simple purification step is sufficient to provide the conjugation ready oligosaccharides in good yield

Water Quality in Rainwater Tanks in Rural and Metropolitan Areas of New South Wales, Australia

This paper compares the water quality of rainwater tanks throughout the Sydney metropolitan area to that in rural New South Wales, Australia. The water quality is compared against the Australian Guidelines for Water Recycling (AGWR) to determine if the untreated rainwater from both areas can be considered suitable for non-potable water supply without filtration. Additionally this paper reports on a set of experiments where rainwater collected from a typical domestic roof in Sydney, New South Wales, Australia was treated by a pre-treatment of granular activated carbon (GAC) adsorption filter followed by micro-filtration. The GAC column removed the pollutants through an adsorption mechanism. GAC is a macroporous solid with a very large surface area providing many sites for adsorption and it is this property that makes it an efficient adsorbent. The parameters analysed were ammonia, anions and cations, heavy metals, nitrate and nitrite, pH, total hardness, total organic carbon, total suspended solids and turbidity. The results indicate that before treatment, the rainwater already complied to many of the parameters specified in the AGWR, certain pollutants have the potential at times to exceed the AGWR. The water quality was within the AGWR limits after the treatment. The micro- filtration flux values demonstrate that rainwater was able to be filtered through the membranes under low gravitational heads that are typically available in a rainwater tank while still producing sufficient membrane flux and pollutant removal rates

Modular automated solid phase synthesis of dermatan sulfate oligosaccharides

Dermatan sulfates are glycosaminoglycan polysaccharides that serve a multitude of biological roles as part of the extracellular matrix. Orthogonally protected D-galactosamine and L-iduronic acid building blocks and a photo- cleavable linker are instrumental for the automated synthesis of dermatan sulfate oligosaccharides. Conjugation-ready oligosaccharides were obtained in good yield

Tree defence and bark beetles in a drying world: carbon partitioning, functioning and modelling.

Drought has promoted large-scale, insect-induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under on-going climate change. Here we propose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: (1) there is a trade-off in tree carbon investment between primary and secondary metabolites (e.g. growth vs defence); (2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and (3) implementing conifer-bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large-scale vegetation models, the under-representation of insect-induced tree mortality

Stark tuning of the charge states of a two-donor molecule in silicon

Gate control of phosphorus donor based charge qubits in Si is investigated using a tight-binding approach. Excited molecular states of P2+ are found to impose limits on the allowed donor separations and operating gate voltages. The effects of surface (S) and barrier (B) gates are analyzed in various voltage regimes with respect to the quantum confined states of the whole device. Effects such as interface ionization, saturation of the tunnel coupling, sensitivity to donor and gate placement are also studied. It is found that realistic gate control is smooth for any donor separation, although at certain donor orientations the S and B gates may get switched in functionality. This paper outlines and analyzes the various issues that are of importance in practical control of such donor molecular systems.Comment: 8 pages, 9 figure

Database Search Strategies for Proteomic Data Sets Generated by Electron Capture Dissociation Mass Spectrometry

Large data sets of electron capture dissociation (ECD) mass spectra from proteomic experiments are rich in information; however, extracting that information in an optimal manner is not straightforward. Protein database search engines currently available are designed for low resolution CID data, from which Fourier transform ion cyclotron resonance (FT-ICR) ECD data differs significantly. ECD mass spectra contain both z-prime and z-dot fragment ions (and c-prime and c-dot); ECD mass spectra contain abundant peaks derived from neutral losses from charge-reduced precursor ions; FT-ICR ECD spectra are acquired with a larger precursor m/z isolation window than their low-resolution CID counterparts. Here, we consider three distinct stages of postacquisition analysis: (1) processing of ECD mass spectra prior to the database search; (2) the database search step itself and (3) postsearch processing of results. We demonstrate that each of these steps has an effect on the number of peptides identified, with the postsearch processing of results having the largest effect. We compare two commonly used search engines: Mascot and OMSSA. Using an ECD data set of modest size (3341 mass spectra) from a complex sample (mouse whole cell lysate), we demonstrate that search results can be improved from 630 identifications (19% identification success rate) to 1643 identifications (49% identification success rate). We focus in particular on improving identification rates for doubly charged precursors, which are typically low for ECD fragmentation. We compare our presearch processing algorithm with a similar algorithm recently developed for electron transfer dissociation (ETD) data

Cross-talk compensation of hyperfine control in donor qubit architectures

We theoretically investigate cross-talk in hyperfine gate control of donor-qubit quantum computer architectures, in particular the Kane proposal. By numerically solving the Poisson and Schr\"{o}dinger equations for the gated donor system, we calculate the change in hyperfine coupling and thus the error in spin-rotation for the donor nuclear-electron spin system, as the gate-donor distance is varied. We thus determine the effect of cross-talk - the inadvertent effect on non-target neighbouring qubits - which occurs due to closeness of the control gates (20-30nm). The use of compensation protocols is investigated, whereby the extent of crosstalk is limited by the application of compensation bias to a series of gates. In light of these factors the architectural implications are then considered.Comment: 15 pages, 22 figures, submitted to Nanotechnolog

Tree defence and bark beetles in a drying world: carbon partitioning, functioning and modelling

Drought has promoted large‐scale, insect‐induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under on‐going climate change. Here we propose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: 1) there is a trade‐off in tree carbon investment between primary and secondary metabolites (e.g. growth vs. defence); 2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and 3) implementing conifer‐bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large‐scale vegetation models, the under‐representation of insect‐induced tree mortality

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