Characterization and modelling of antisolvent crystallization of salicylic acid in a continuous oscillatory baffled crystallizer

Using antisolvent crystallisation of salicylic acid as the model process, we report our experimental investigation into the temporal and spatial steady states of solution concentration and mean crystal size in a continuous oscillatory baffled crystallizer. The evolutions of the two parameters over time and distance along the crystallizer are measured for a variety of operating conditions. The results show that the attainment of long term temporal and spatial stabilities (>100 residence times) for the solute concentrations are easily achieved, whereas the temporal steady states of the mean crystal size are more difficult to accomplish, even though the spatial steady states have been obtained. A simplified population balance model is applied to the experimental data for the determination of nucleation and growth kinetic parameters. From which both the solution concentration and the mean size were predicted and matched to experimental values reasonably well. In addition, we have identified and executed the conditions of long term steady states for extended operation of 6.25. h to produce close to 1. kg of crystal product with minimal variation in crystal size (±3.01. μm)

Precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor operated in batch at constant power density

A meso oscillatory flow reactor (OFR) was successfully applied for the precipitation of hydroxyapatite (HAp) nanoparticles. Mixing efficiency of the mesoreactor operated batchwise in a vertical tube was evaluated at constant power density, by monitoring variation of hue values upon mixing both spatially and temporally. The best operating conditions for fast mixing and a more homogeneous reaction medium were verified for f = 0.83 Hz and x0 = 4.5 mm. HAp precipitation was then carried out under these conditions at 37 °C for different mixing Ca/P molar ratios. HAp nanoparticles with a mean size (d50) of about 67 nm and a narrow size distribution were obtained. Furthermore, the obtained results show the advantages of the meso-OFR over a stirred tank batch reactor due to the production, about four times faster, of smaller and more uniform HAp nanoparticles. © 2013 American Institute of Chemical Engineers AIChE J, 2013This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/42992/2008) through the MIT-Portugal Program, Bioengineering Systems Focus Area. The authors are thankful to Dr Jorge Ferreira from LNEG (Laboratorio Nacional de Energia e Geologia, Portugal) for carrying out the X-ray measurements and his help with the interpretation of results

Big data-led cancer research, applications and insights

Insights distilled from integratingmultiple big-data or "omic" datasets have revealed functional hierarchies of molecular networks driving tumorigenesis and modifiers of treatment response. Identifying these novel key regulatory and dysregulated elements is now informing personalized medicine. Crucially, although there are many advantages to this approach, there are several key considerations to address. Here, we examine how this big data-led approach is impacting many diverse areas of cancer research, through review of the key presentations given at the Irish Association for Cancer Research Meeting and importantly how the results may be applied to positively affect patient outcomes

Quasilocal Thermodynamics of Dilaton Gravity coupled to Gauge Fields

We consider an Einstein-Hilbert-Dilaton action for gravity coupled to various types of Abelian and non-Abelian gauge fields in a spatially finite system. These include Yang-Mills fields and Abelian gauge fields with three and four-form field strengths. We obtain various quasilocal quantities associated with these fields, including their energy and angular momentum, and develop methods for calculating conserved charges when a solution possesses sufficient symmetry. For stationary black holes, we find an expression for the entropy from the micro-canonical form of the action. We also find a form of the first law of black hole thermodynamics for black holes with the gauge fields of the type considered here.Comment: 41 pages, latex, uses fonts provided by AMSTe

A new and integrated hydro-economic accounting and analytical framework for water resources: A case study for North China

Water is a critical issue in China for a variety of reasons. China is poor of water resources with 2300 m3 of per capita availability, which is less than of the world average. This is exacerbated by regional differences; e.g. North China's water availability is only about 271 m3 of per capita value, which is only of the world's average. Furthermore, pollution contributes to water scarcity and is a major source for diseases, particularly for the poor. The Ministry of Hydrology [1997. China's Regional Water Bullets. Water Resource and Hydro-power Publishing House, Beijing, China] reports that about 65–80% of rivers in North China no longer support any economic activities. Previous studies have emphasized the amount of water withdrawn but rarely take water quality into consideration. The quality of the return flows usually changes; the water quality being lower than the water flows that entered the production process initially. It is especially important to measure the impacts of wastewater to the hydro-ecosystem. Thus, water consumption should not only account for the amount of water inputs but also the amount of water contaminated in the hydro-ecosystem by the discharged wastewater. In this paper we present a new accounting and analytical approach based on economic input–output modelling combined with a mass balanced hydrological model that links interactions in the economic system with interactions in the hydrological system. We thus follow the tradition of integrated economic–ecologic input–output modelling. Our hydro-economic accounting framework and analysis tool allows tracking water consumption on the input side, water pollution leaving the economic system and water flows passing through the hydrological system thus enabling us to deal with water resources of different qualities. Following this method, the results illustrate that North China requires 96% of its annual available water, including both water inputs for the economy and contaminated water that is ineligible for any uses

RNA from a simple-tandem repeat is required for sperm maturation and male fertility in Drosophila melanogaster.

Tandemly-repeated DNAs, or satellites, are enriched in heterochromatic regions of eukaryotic genomes and contribute to nuclear structure and function. Some satellites are transcribed, but we lack direct evidence that specific satellite RNAs are required for normal organismal functions. Here, we show satellite RNAs derived from AAGAG tandem repeats are transcribed in many cells throughout Drosophila melanogaster development, enriched in neurons and testes, often localized within heterochromatic regions, and important for viability. Strikingly, we find AAGAG transcripts are necessary for male fertility, and that AAGAG RNA depletion results in defective histone-protamine exchange, sperm maturation and chromatin organization. Since these events happen late in spermatogenesis when the transcripts are not detected, we speculate that AAGAG RNA in primary spermatocytes 'primes' post-meiosis steps for sperm maturation. In addition to demonstrating essential functions for AAGAG RNAs, comparisons between closely related Drosophila species suggest that satellites and their transcription evolve quickly to generate new functions

Cosmological Birefringence: an Astrophysical test of Fundamental Physics

We review the methods used to test for the existence of cosmological birefringence, i.e. a rotation of the plane of linear polarization for electromagnetic radiation traveling over cosmological distances, which might arise in a number of important contexts involving the violation of fundamental physical principles. The main methods use: (1) the radio polarization of radio galaxies and quasars, (2) the ultraviolet polarization of radio galaxies, and (3) the cosmic microwave background polarization. We discuss the main results obtained so far, the advantages and disadvantages of each method, and future prospects.Comment: To appear in the Proceedings of the JENAM 2010 Symposium "From Varying Couplings to Fundamental Physics", held in Lisbon, 6-10 Sept. 201