Formation of oligopeptides in high yield under simple programmable conditions

Many high-yielding reactions for forming peptide bonds have been developed but these are complex, requiring activated amino-acid precursors and heterogeneous supports. Herein we demonstrate the programmable one-pot dehydration–hydration condensation of amino acids forming oligopeptide chains in around 50% yield. A digital recursive reactor system was developed to investigate this process, performing these reactions with control over parameters such as temperature, number of cycles, cycle duration, initial monomer concentration and initial pH. Glycine oligopeptides up to 20 amino acids long were formed with very high monomer-to-oligomer conversion, and the majority of these products comprised three amino acid residues or more. Having established the formation of glycine homo-oligopeptides, we then demonstrated the co-condensation of glycine with eight other amino acids (Ala, Asp, Glu, His, Lys, Pro, Thr and Val), incorporating a range of side-chain functionality

Targeting of anionic membrane species by lanthanide(III) complexes: towards improved MRI contrast agents for apoptosis

No abstract available

Stereoselective assembly of gigantic chiral molybdenum blue wheels using lanthanide ions and amino acids

The synthesis of chiral polyoxometalates (POMs) is a challenge because of the difficulty to induce the formation of intrinsically chiral metal-oxo frameworks. Herein we report the stereoselective synthesis of a series of gigantic chiral Mo Blue (MB) POM clusters 1–5 that are formed by exploiting the synergy between coordinating lanthanides ions as symmetry breakers to produce MBs with chiral frameworks decorated with amino acids ligands; these promote the selective formation of enantiopure MBs. All the compounds share the same framework archetype, based on {Mo124Ce4}, which forms an intrinsically chiral Δ or Λ configurations, controlled by the configurations of functionalized chiral amino acids. The chirality and stability of 1–5 in solution are confirmed by circular dichroism, 1H NMR, and electrospray ion mobility–mass spectrometry studies. In addition, the framework of the {Mo124Ce4} MB not only behaves as a host able to trap a chiral {Mo8} cluster that is not accessible by traditional synthesis but also promotes the transformation of tryptophan to kynurenine in situ. This work demonstrates the potential and applicability of our synthetic strategy to produce gigantic chiral POM clusters capable of host–guest chemistry and selective synthetic transformations

Environmental control programs the emergence of distinct functional ensembles from unconstrained chemical reactions

Many approaches to the origin of life focus on how the molecules found in biology might be made in the absence of biological processes, from the simplest plausible starting materials. Another approach could be to view the emergence of the chemistry of biology as process whereby the environment effectively directs “primordial soups” toward structure, function, and genetic systems over time. This does not require the molecules found in biology today to be made initially, and leads to the hypothesis that environment can direct chemical soups toward order, and eventually living systems. Herein, we show how unconstrained condensation reactions can be steered by changes in the reaction environment, such as order of reactant addition, and addition of salts or minerals. Using omics techniques to survey the resulting chemical ensembles we demonstrate there are distinct, significant, and reproducible differences between the product mixtures. Furthermore, we observe that these differences in composition have consequences, manifested in clearly different structural and functional properties. We demonstrate that simple variations in environmental parameters lead to differentiation of distinct chemical ensembles from both amino acid mixtures and a primordial soup model. We show that the synthetic complexity emerging from such unconstrained reactions is not as intractable as often suggested, when viewed through a chemically agnostic lens. An open approach to complexity can generate compositional, structural, and functional diversity from fixed sets of simple starting materials, suggesting that differentiation of chemical ensembles can occur in the wider environment without the need for biological machinery

A randomised controlled trial of laser scanning and casting for the construction of ankle foot orthoses

Study Design: Randomised controlled trial with blinding of orthotists and patients to the construction technique used. Background: Three-dimensional laser scanning has been used for patient measurement for cranial helmets and spinal braces. Ankle foot orthoses are commonly prescribed for children with orthopaedic conditions. This trial sought to compare ankle foot orthoses produced by laser scanning or traditional plaster casting. Objectives: Assessment of the effectiveness and efficiency of using laser scanning to produce AFOs. Methods: A randomised double blind trial comparing fabrication of AFOs from casts or laser scans. Results: The time spent in the rectification and moulding of scanned AFOs was around 50% less than for cast AFOs. A non-significant increase of 9 days was seen in the time to delivery to the patient for LSCAD/CAM. There was a higher incidence of problems with the scan-based AFOs at delivery of the device, but no difference in how long the AFOs lasted. Costs associated with laser scanning were not significantly different from traditional methods of AFO manufacture. Conclusions: Compared with conventional casting techniques laser scan based AFO manufacture neither significantly improved the quality of the final product nor delivered a useful saving in time

Catching Element Formation In The Act

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

Seabirds enhance coral reef productivity and functioning in the absence of invasive rats

Biotic connectivity between ecosystems can provide major transport of organic matter and nutrients, influencing ecosystem structure and productivity1, yet the implications are poorly understood owing to human disruptions of natural flows2. When abundant, seabirds feeding in the open ocean transport large quantities of nutrients onto islands, enhancing the productivity of island fauna and flora3,4. Whether leaching of these nutrients back into the sea influences the productivity, structure and functioning of adjacent coral reef ecosystems is not known. Here we address this question using a rare natural experiment in the Chagos Archipelago, in which some islands are rat-infested and others are rat-free. We found that seabird densities and nitrogen deposition rates are 760 and 251 times higher, respectively, on islands where humans have not introduced rats. Consequently, rat-free islands had substantially higher nitrogen stable isotope (δ15N) values in soils and shrubs, reflecting pelagic nutrient sources. These higher values of δ15N were also apparent in macroalgae, filter-feeding sponges, turf algae and fish on adjacent coral reefs. Herbivorous damselfish on reefs adjacent to the rat-free islands grew faster, and fish communities had higher biomass across trophic feeding groups, with 48% greater overall biomass. Rates of two critical ecosystem functions, grazing and bioerosion, were 3.2 and 3.8 times higher, respectively, adjacent to rat-free islands. Collectively, these results reveal how rat introductions disrupt nutrient flows among pelagic, island and coral reef ecosystems. Thus, rat eradication on oceanic islands should be a high conservation priority as it is likely to benefit terrestrial ecosystems and enhance coral reef productivity and functioning by restoring seabird-derived nutrient subsidies from large areas of ocean

Feeding ecology of seabirds nesting at the Abrolhos Islands, Western Australia

Over one million pairs of seabirds breed annually on the Houtman Abrolhos island group, 60 km off the mid-western coast of Australia, the largest seabird breeding station in the eastern Indian Ocean. This report describes in detail the diets and breeding patterns of six key seabird species that nest at the Abrolhos Islands. Lesser Noddy - Anous tenuirostris melanops Common (Brown) Noddy - Anous stolidus Sooty Tern - Sterna fuscata Crested Tern - Sterna bergii Roseate Tern - Sterna dougalli Wedge-tailed Shearwater - Puffinus pacificus The primary management goal of this report is to ensure that fishing activities off the mid-west coast do not adversely affect seabirds on the Abrolhos Islands. The main commercial fishing operations in the region target western rock lobster with traps, scallops with demersal trawls, a tropical sardine (but known locally as scaly mackerel) with purse seine and a variety of reef associated and large pelagic fish species with hook and line

Configurable Nanosized Metal Oxide Oligomers via Precise “Click” Coupling Control of Hybrid Polyoxometalates

Polyoxometalates (POMs) are discrete clusters of redox-active metal oxides, many of which can be linked to organic moieties. Here, we show how it is possible to link Mn Anderson POMs to terminal alkyne and azide groups and develop appropriate conditions for their Cu-catalyzed alkyne–azide cycloaddition (or “click” reaction). These coupling reactions are then used to link the clusters together, forming monodisperse linear Mn Anderson oligomers, here with examples ranging in size from two to five clusters. These oligomers are built up sequentially using a combination of mono- and difunctionalized clusters, giving an unprecedented level of control over the size and structure of the resulting hybrid POMs. This new synthetic methodology therefore opens the way for the synthesis of metal oxide hybrid oligomers and polymers by coupling control, minimizing side products, producing nanosized molecular hybrid organic–inorganic oxides ca. 4–9 nm in size, with molecular weights ranging 2–10 kDa