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

A new method to prevent degradation of lithium–oxygen batteries: reduction of superoxide by viologen

Lithium–oxygen battery development is hampered by degradation reactions initiated by superoxide, which is formed in the pathway of oxygen reduction to peroxide. This work demonstrates that the superoxide lifetime is drastically decreased upon addition of ethyl viologen, which catalyses the reduction of superoxide to peroxide

Effects of site dilution on the magnetic properties of geometrically frustrated antiferromagnets

The effect of site dilution by non magnetic impurities on the susceptibility of geometrically frustrated antiferromagnets (kagome and pyrochlore lattices) is discussed in the framework of the Generalized Constant Coupling model, for both classical and quantum Heisenberg spins. For the classical diluted pyrochlore lattice, excellent agreement is found when compared with Monte Carlo data. Results for the quantum case are also presented and discussed.Comment: 5 pages, 3 figure

Light and Life: Exotic Photosynthesis in Binary Star Systems

The potential for hosting photosynthetic life on Earth-like planets within binary/multiple stellar systems was evaluated by modelling the levels of photosynthetically active radiation (PAR) such planets receive. Combinations of M and G stars in: (i) close-binary systems; (ii) wide-binary systems and (iii) three-star systems were investigated and a range of stable radiation environments found to be possible. These environmental conditions allow for the possibility of familiar, but also more exotic forms of photosynthetic life, such as infrared photosynthesisers and organisms specialised for specific spectral niches.Comment: Accepted for publication in: Astrobiolog

Regulation mechanisms in spatial stochastic development models

The aim of this paper is to analyze different regulation mechanisms in spatial continuous stochastic development models. We describe the density behavior for models with global mortality and local establishment rates. We prove that the local self-regulation via a competition mechanism (density dependent mortality) may suppress a unbounded growth of the averaged density if the competition kernel is superstable.Comment: 19 page

A Controlled Study on the Characterisation of Bioaerosols Emissions from Compost

Bioaerosol emissions arising from biowaste treatment are an issue of public concern. To better characterise the bioaerosols, and to assess a range of measurement methods, we aerosolised green waste compost under controlled conditions. Viable and non-viable Andersen samplers, cyclone samplers and a real time bioaerosol detection system (Spectral Intensity Bioaerosol Sensor (SIBS)) were deployed simultaneously. The number-weighted fraction of fluorescent particles was in the range 22–26% of all particles for low and high emission scenarios. Overall fluorescence spectral profiles seen by the SIBS exhibited several peaks across the 16 wavelength bands from 298 to 735 nm. The size-fractionated endotoxin profile showed most endotoxin resided in the 2.1–9 μm aerodynamic diameter fraction, though up to 27% was found in a finer size fraction. A range of microorganisms were detected through culture, Matrix Assisted Laser Desorption and Ionisation Time of Flight Mass Spectrometry (MALDI-TOF) and quantitative polymerase chain reaction (qPCR), including Legionella pneumophila serogroup 1. These findings contribute to our knowledge of the physico-chemical and biological characteristics of bioaerosols from composting sites, as well as informing future monitoring approaches and data interpretation for bioaerosol measurement

Amplification of evanescent waves in a lossy left-handed material slab

We carry out finite-difference time-domain (FDTD) simulations, with a specially-designed boundary condition, on pure evanescent waves interacting with a lossy left-handed material (LHM) slab. Our results provide the first full-wave numerical evidence for the amplification of evanescent waves inside a LHM slab of finite absorption. The amplification is due to the interactions between the evanescent waves and the coupled surface polaritons at the two surfaces of the LHM slab and the physical process can be described by a simple model.Comment: 4 pages, 2 figure

A Parallelizable Heuristic for Solving the Generic Materials and Operations Planning in a Supply Chain Network: A Case Study from the Automotive Industry

[EN] A trend in up-to date developments in multi-site operations planning models is to consider in details the different ways to produce, buy or transport products and the distributed decision-making process for operations planning. One of the most generic approaches to support global optimization in those supply chain networks by considering all the different operations alternatives and product structures is the Generic Materials & Operations Planning Problem. This problem can be modelled by a Mixed Integer Linear Programming model capable of considering production, transportation, procurement tasks and their alternatives and other relevant issues such as packaging. The aim of this paper is to introduce the implementation of a parallelizable heuristic method for materials and operations planning and its application to a case of a Supply Chain Network of the automotive industry. The approach uses variants of the GMOP model to overcome traditional MRP systems' limitations.Maheut ., JP.; García Sabater, JP. (2013). A Parallelizable Heuristic for Solving the Generic Materials and Operations Planning in a Supply Chain Network: A Case Study from the Automotive Industry. IFIP Advances in Information and Communication Technology. 397:151-157. doi:10.1007/978-3-642-40352-1_20S151157397Maheut, J., Garcia-Sabater, J.P.: La Matriz de Operaciones y Materiales y la Matriz de Operaciones y Recursos, un nuevo enfoque para resolver el problema GMOP basado en el concepto del Stroke. Dirección y Organización 45, 46–57 (2011)Garcia-Sabater, J.P., Maheut, J., Marin-Garcia, J.A.: A new formulation technique to model Materials and Operations Planning: the Generic Materials and Operations Planning (GMOP) Problem. European J. Industrial Engineering 7, 119–147 (2013)Mula, J., Maheut, J., Garcia-Sabater, J.P.: Supply Chain Network Design. Journal of Marketing and Operations Management Research 1, 378–383 (2012)Dudek, G., Stadtler, H.: Negotiation-based collaborative planning between supply chains partners. European Journal of Operational Research 163, 668–687 (2005)Torabi, S.A., Hassini, E.: Multi-site production planning integrating procurement and distribution plans in multi-echelon supply chains: an interactive fuzzy goal programming approach. International Journal of Production Research 47, 5475–5499 (2009)Kanyalkar, A.P., Adil, G.K.: Aggregate and detailed production planning integrating procurement and distribution plans in a multi-site environment. International Journal of Production Research 45, 5329–5353 (2007)de Kok, T.G., Fransoo, J.C.: Planning Supply Chain Operations: Definition and Comparison of Planning Concepts. In: Graves, S.C. (ed.) Handbooks in Operations Research and Management Science Supply Chain Management: Design, Coordination and Operation, vol. 11, pp. 597–675. Elsevier (2003)Buschkühl, L., Sahling, F., Helber, S., Tempelmeier, H.: Dynamic capacitated lot-sizing problems: a classification and review of solution approaches. OR Spectrum (2009)Maheut, J., Garcia-Sabater, J.P., Mula, J.: A supply Chain Operations Lot-Sizing and Scheduling Model with Alternative Operations. In: Sethi, S.P., Bogataj, M., Ros-McDonnell, L. (eds.) Proceedings of the Industrial Engineering: Innovative Networks, 5th International Conference on Industrial Engineering and Industrial Management "CIO 2011", Cartagena, Spain, pp. 309–316. Springer, London (2012)Garcia-Sabater, J.P., Maheut, J., Garcia-Sabater, J.J.: A two-stage sequential planning scheme for integrated operations planning and scheduling system using MILP: the case of an engine assembler. Flexible Services and Manufacturing Journal 24, 171–209 (2012)Pinto, J.M., Chen, P., Papageorgiou, L.G.: A discrete/continuous time MILP model for medium term planning of single stage multiproduct plants, pp. 1–6. Elsevier, B.V. (2007)Scheer, A.W.: Business Process Engineering - Reference Models for Industrial Enterprises. Springer (1994)Lin, J.T., Chen, T.L., Lin, Y.T.: Critical material planning for TFT-LCD production industry. International Journal of Production Economics 122, 639–655 (2009)Escudero, L.F.: CMIT, capacitated multi-level implosion tool. European Journal of Operational Research 76, 511–528 (1994)Maheut, J., Garcia-Sabater, J.P., Valero-Herrero, M.: MILP model for solving the supply chain operations scheduling problem with alternative operations considering delay penalization: a case study of a mass customization company. In: Proceedings of the 41st International Conference on Computers & Industrial Engineering, pp. 289–294 (2011

Supernova Bounds on Majoron-emitting decays of light neutrinos

Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure

Constraining neutrino oscillation parameters with current solar and atmospheric data

We analyze the impact of recent solar, atmospheric and reactor data in the determination of the neutrino oscillation parameters, taking into account that both the solar nu_e and the atmospheric nu_mu may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the SNO neutral current, spectral and day/night data by performing also an analysis using only the charged current rate from SNO. The implications of the first 145.1 days of KamLAND data on the determination of the solar neutrino parameters are also discussed in detail. We confirm the clear preference of solar+reactor data for the pure active LMA-MSW solution of the solar neutrino problem, and obtain that the LOW, VAC, SMA and Just-So^2 solutions are disfavored with a Delta_chi^2 = 22, 22, 36, 44, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 43% at 99% CL. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the nu_mu is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% CL, while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a Delta_chi^2 = 34.6 compared to the pure active case.Comment: 28 pages, LaTeX file using RevTEX4, 12 figures and 3 tables included. Improved version including the new KamLAND dat