Preparation of 5-Hydroxymethylfurfural from Glucose and Fructose in Ionic Liquids by Reactive Vacuum Distillation Over a Solid Catalyst

BACKGROUND: The production of 5-hydroxymethylfurfural (5-HMF) from biomass provides an alternative pathway for many commercial chemicals and polymers particularly for countries with high insolation such as sub-Saharan Africa. OBJECTIVE: The goal is continuous or semi-continuous dehydration of glucose and fructose to 5-HMF over a reusable castalyst in a process which is commmercial viable. METHOD: We deploy a separable and resuable catalyst, a low volatility solvent and reactive vacuum distillation. Results: Using a sulfated zirconia (SZ) catalyst in 1-butyl-3-methylimidazolium chloride [BMIM]Cl ionic liquid as solvent, we are able to separate the product by reactive vacuum distillation and obtain yields for 5-HMF of 82% and 65% at a 5 g experimental scale using fructose and glucose as substrates in a 2 h reaction time at 180 oC. The ionic liquid and SZ exhibited high activity when recycled for five successive trials. CONCLUSION: The low volatility solvent and solid catalyst allow for reactive vacuum distillation taking the sequence of steps from biomass such as Cassava to 5-HMF closer to commercial viability

Sea salt as a potential ocean mirror material

One way to increase planetary albedo in order to ameliorate global warming is to use ocean foams. The energy needed to maintain such foams, even if drawn from wave or wind is high and so they must be persistent, ideally surviving up to a month. While studying combinations of surfactants and gelling agents to make long-lived foams in salt water, it was apparent that some foams developed progressively higher reflectance as the upper surface dried. Scanning electron microscopy of the upper surface revealed 0.5 mm, near-monodisperse salt crystals. Thus with a refractive index of ∼1.5, sea salt, being in somewhat prodigious supply, now enters the arena as a potential mirror material. Its reflectance depends on the microstructure, specifically on the inhibition of Ostwald ripening. Studies were therefore carried out to investigate particle size effects in a membrane such as a foamed gel in which seawater dries on the upper surface. It was demonstrated that the organic additives used to create foam persistence also mediated sea salt crystallisation and in this way drastically modified the reflectance of the upper layer. These experiments suggest a new direction of research in planetary surface albedo modification

Hydrophobic Polymers from Food Waste: Resources and Synthesis

The food waste generated annually is approximately 1.3 Pg. It contains chemical feedstock that could be diverted to materials production as the mineral oil price rises, incurring no conflict over land use and providing new wealth-creating opportunities for food-producing countries. It potentially realigns the industrial and agricultural sectors of national economies. Food waste production scales with population as does demand for materials. This review builds upon previous landmark papers in Polymer Reviews that address biomass in polymer production. It surveys the current global food-waste resource and demonstrates how it could be used in the generation of hydrophobic polymers

Graveyards on the Move: The Spatio-Temporal Distribution of Dead Ophiocordyceps-Infected Ants

Parasites are likely to play an important role in structuring host populations. Many adaptively manipulate host behaviour, so that the extended phenotypes of these parasites and their distributions in space and time are potentially important ecological variables. The fungus Ophiocordyceps unilateralis, which is pan-tropical in distribution, causes infected worker ants to leave their nest and die under leaves in the understory of tropical rainforests. Working in a forest dynamic plot in Southern Thailand we mapped the occurrence of these dead ants by examining every leaf in 1,360 m2 of primary rainforest. We established that high density aggregations exist (up to 26 dead ants/m2), which we coined graveyards. We further established that graveyards are patchily distributed in a landscape with no or very few O. unilateralis-killed ants. At some, but not all, spatial scales of analysis the density of dead ants correlated with temperature, humidity and vegetation cover. Remarkably, having found 2243 dead ants inside graveyards we only found 2 live ants of the principal host, ant Camponotus leonardi, suggesting that foraging host ants actively avoid graveyards. We discovered that the principal host ant builds nests in high canopy and its trails only occasionally descend to the forest floor where infection occurs. We advance the hypothesis that rare descents may be a function of limited canopy access to tree crowns and that resource profitability of such trees is potentially traded off against the risk of losing workers due to infection when forest floor trails are the only access routes. Our work underscores the need for an integrative approach that recognises multiple facets of parasitism, such as their extended phenotypes

Branching dendrites with resonant membrane: a “sum-over-trips” approach

Dendrites form the major components of neurons. They are complex branching structures that receive and process thousands of synaptic inputs from other neurons. It is well known that dendritic morphology plays an important role in the function of dendrites. Another important contribution to the response characteristics of a single neuron comes from the intrinsic resonant properties of dendritic membrane. In this paper we combine the effects of dendritic branching and resonant membrane dynamics by generalising the “sum-over-trips” approach (Abbott et al. in Biol Cybernetics 66, 49–60 1991). To illustrate how this formalism can shed light on the role of architecture and resonances in determining neuronal output we consider dual recording and reconstruction data from a rat CA1 hippocampal pyramidal cell. Specifically we explore the way in which an Ih current contributes to a voltage overshoot at the soma

Jumping without Using Legs: The Jump of the Click-Beetles (Elateridae) Is Morphologically Constrained

To return to their feet, inverted click-beetles (Elateridae) jump without using their legs. When a beetle is resting on its dorsal side, a hinge mechanism is locked to store elastic energy in the body and releases it abruptly to launch the beetle into the air. While the functional morphology of the jumping mechanism is well known, the level of control that the beetle has over this jumping technique and the mechanical constraints governing the jumps are not entirely clear. Here we show that while body rotations in air are highly variable, the jumps are morphologically constrained to a constant “takeoff” angle (79.9°±1.56°, n = 9 beetles) that directs 98% of the jumping force vertically against gravity. A physical-mathematical model of the jumping action, combined with measurements from live beetle, imply that the beetle may control the speed at takeoff but not the jumping angle. In addition, the model shows that very subtle changes in the exact point of contact with the ground can explain the vigorous rotations of the body seen while the beetle is airborne. These findings suggest that the evolution of this unique non-legged jumping mechanism resulted in a jumping technique that is capable of launching the body high into the air but it is too constrained and unstable to allow control of body orientation at landing

Disease Dynamics in a Specialized Parasite of Ant Societies

Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests and that hyperparasites often castrate Ophiocordyceps. However, once fruiting bodies become sexually mature they appear robust. Such parasite life-history traits are consistent with iteroparity– a reproductive strategy rarely considered in fungi. We discuss how tropical habitats with high biodiversity of hyperparasites and high spore mortality has likely been crucial for the evolution and maintenance of iteroparity in parasites with low dispersal potential

The selective conversion of D-limonene to p,alpha-dimethylstyrene

Reaction conditions to facilitate the conversion of D-limonene selectively to p,α-dimethylstyrene (DMS) are described, in order to subsequently produce polymeric materials from biomass sourced from food waste. Limonene was dehydrogenated with several palladium catalysts and different solvents and bases, with copper chloride as oxidant at temperatures of 70–120 °C. Reaction conditions were identified using Pd(OAc)2 for the selective formation of only DMS from limonene in 2–5 hours, enabling the facile separation of DMS from unreacted starting material by vacuum distillation

Conservation genomics reveals possible illegal trade routes and admixture across pangolin lineages in Southeast Asia

The use of genome-wide genetic markers is an emerging approach for informing evidence-based management decisions for highly threatened species. Pangolins are the most heavily trafficked mammals across illegal wildlife trade globally, but critically endangered Sunda pangolins (Manis javanica) have not been widely studied in insular Southeast Asia. We used > 12,000 single nucleotide polymorphic markers (SNPs) to assign pangolin seizures from illegal trade of unknown origin to possible geographic sources via genetic clustering with pangolins of known origin. Our SNPs reveal three previously unrecognized genetic lineages of Sunda pangolins, possibly from Borneo, Java and Singapore/Sumatra. The seizure assignments suggest the majority of pangolins were traded from Borneo to Java. Using mitochondrial markers did not provide the same resolution of pangolin lineages, and to explore if admixture might explain these differences, we applied sophisticated tests of introgression using > 2000 SNPs to investigate secondary gene flow between each of the three Sunda pangolin lineages. It is possible the admixture which we discovered is due to human-mediated movements of pangolins. Our findings impact a range of conservation actions, including tracing patterns of trade, repatriation of rescue animals, and conservation breeding. In order to conserve genetic diversity, we suggest that, pending further research, each pangolin lineage should as a precaution be protected and managed as an evolutionarily distinct conservation unit