Valorization of biomass: deriving more value from waste

Most of the carbon-based compounds currently manufactured by the chemical industry are derived from petroleum. The rising cost and dwindling supply of oil have been focusing attention on possible routes to making chemicals, fuels, and solvents from biomass instead. In this context, many recent studies have assessed the relative merits of applying different dedicated crops to chemical production. Here, we highlight the opportunities for diverting existing residual biomass--the by-products of present agricultural and food-processing streams--to this end.     

One-step fabrication of supramolecular microcapsules from microfluidic droplets

Although many techniques exist for preparing microcapsules, it is still challenging to fabricate them in an efficient and scalable process without compromising functionality and encapsulation efficiency. We demonstrated a simple one-step approach that exploits a versatile host-guest system and uses microfluidic droplets to generate porous microcapsules with easily customizable functionality. The capsules comprise a polymer-gold nanoparticle composite held together by cucurbit[8]uril ternary complexes. The dynamic yet highly stable micrometer-sized structures can be loaded in one step during capsule formation and are amenable to on-demand encapsulant release. The internal chemical environment can be probed with surface enhanced Raman spectroscopy.     

Topography of the northern hemisphere of Mercury from MESSENGER laser altimetry

Laser altimetry by the MESSENGER spacecraft has yielded a topographic model of the northern hemisphere of Mercury. The dynamic range of elevations is considerably smaller than those of Mars or the Moon. The most prominent feature is an extensive lowland at high northern latitudes that hosts the volcanic northern plains. Within this lowland is a broad topographic rise that experienced uplift after plains emplacement. The interior of the 1500-km-diameter Caloris impact basin has been modified so that part of the basin floor now stands higher than the rim. The elevated portion of the floor of Caloris appears to be part of a quasi-linear rise that extends for approximately half the planetary circumference at mid-latitudes. Collectively, these features imply that long-wavelength changes to Mercury's topography occurred after the earliest phases of the planet's geological history.     

Optimizing early detection of avian influenza H5N1 in backyard and free-range poultry production systems in Thailand

For infectious diseases such as highly pathogenic avian influenza caused by the H5N1 virus (A/H5N1 HP), early warning system is essential. Evaluating the sensitivity of surveillance is a necessary step in ensuring an efficient and sustainable system. Stochastic scenario tree modeling was used here to assess the sensitivity of the A/H5N1 HP surveillance system in backyard and free-grazing duck farms in Thailand. The whole surveillance system for disease detection was modeled with all components and the sensitivity of each component and of the overall system was estimated. Scenarios were tested according to selection of high-risk areas, inclusion of components and sampling procedure, were tested. Nationwide passive surveillance (SSC1) and risk-based clinical X-ray (SSC2) showed a similar sensitivity level, with a median sensitivity ratio of 0.96 (95% CI 0.40-15.00). They both provide higher sensitivity than the X-ray laboratory component (SSC3). With the current surveillance design, the sensitivity of detection of the overall surveillance system when the three components are implemented, was equal to 100% for a farm level prevalence of 0.05% and 82% (95% CI 71-89%) for a level of infection of 3 farms. Findings from this study illustrate the usefulness of scenario-tree modeling to document freedom from diseases in developing countries.     

Relationship between increased albendazole systemic exposure and changes in single nucleotide polymorphisms on the β-tubulin isotype 1 encoding gene in Haemonchus contortus

Resistance to benzimidazole anthelmintics in the nematode Haemonchus contortus has been correlated with single nucleotide polymorphisms (SNPs) on the β-tubulin isotype 1 gene. Three mutations can be used as markers for the detection of resistance, namely SNPs at position 200 and 167 (both TTC to TAC) or at position 198 (GAA to GCA). Harbouring a resistance genotype at any one of these codons can lead to a resistant phenotype. Our objective in this study was to analyse the frequencies of the three mutations when the albendazole dose rate and selection pressure were increased. We used adult H. contortus (males and females) collected directly from the abomasum of untreated lambs, or lambs treated with the manufacturer's recommended dose rate (5mg/kg), three times the recommended dose rate (15 mg/kg), or nine times the recommended dose rate (45 mg/kg). Anthelmintic efficacy was determined by worm and egg count reductions. For the surviving worms of the four treatment groups, the frequencies of each resistance SNP at codons 167, 200 and 198 were measured using pyrosequencing. Our results showed a strong relationship between an increasing dose rate and an increase in the frequency of the (TAC)(200) SNP and a decrease in the (TAC)(167) SNP. All worms genotyped were GAA at codon 198.