Cultivation medium design via elemental balancing for tetraselmis suecica

The primary requirements for high-biomass-concentration microalgal cultivation include a photon source and distribution, efficient gas exchange and suitable growth medium composition. However, for mass outdoor production of microalgae, growth medium composition is a major controlling factor as most of the other factors such as light source and distribution are virtually uncontrollable. This work utilises an elemental balance approach between growth medium and biomass compositions to obtain high-density microalgal cultures in an open system. F medium, commonly used for the cultivation of marine microalgae such as Tetraselmis suecica was redesigned on the basis of increasing the biomass capacity of its major deficient components to support high biomass concentrations (τ ∼ 5.0 % for N, S and τ ∼ 10 % P), and the entire formulation was dissolved in 0.2 um sterile filtered natural seawater. Results show that the new medium (F') displayed a maximum biomass concentration and total lipid concentration of 1.29 g L 1 and 108.7 mg L 1 respectively, which represents over 2-fold increase compared to that of the F medium. Keeping all variables constant except growth medium, and using F medium as the base case of 1 medium cost (MC) unit mg -1 lipid, the F' medium yielded lipid at a cost of only 0.35 MC unit mg -1 lipids. These results show that greater amounts of biomass and lipids can be obtained more economically with minimal extra effort simply by using an optimised growth medium.

Process considerations related to the microencapsulation of plasmid DNA via ultrasonic atomization

An effective means of facilitating DNA vaccine delivery to antigen presenting cells is through biodegradable microspheres. Microspheres offer distinct advantages over other delivery technologies by providing release of DNA vaccine in its bioactive form in a controlled fashion. In this study, biodegradable poly(D,L-lactide-coglycolide) (PLGA) microspheres containing polyethylenimine (PEI) condensed plasmid DNA (pDNA) were prepared using a 40 kHz ultrasonic atomization system. Process synthesis parameters, which are important to the scale-up of microspheres that are suitable for nasal delivery (i.e., less than 20 μm), were studied. These parameters include polymer concentration; feed flowrate; volumetric ratio of polymer and pDNA-PEI (plasmid DNA-polyethylenimine) complexes; and nitrogen to phosphorous (N/P) ratio. PDNA encapsulation efficiencies were predominantly in the range 82-96%, and the mean sizes of the particle were between 6 and 15 μm. The ultrasonic synthesis method was shown to have excellent reproducibility. PEI affected morphology of the microspheres, as it induced the formation of porous particles that accelerate the release rate of pDNA. The PLGA microspheres displayed an in vitro release of pDNA of 95-99% within 30 days and demonstrated zero order release kinetics without an initial spike of pDNA. Agarose electrophoresis confirmed conservation of the supercoiled form of pDNA throughout the synthesis and in vitro release stages. It was concluded that ultrasonic atomization is an efficient technique to overcome the key obstacles in scaling-up the manufacture of encapsulated vaccine for clinical trials and ultimately, commercial applications.

Rapid production of a plasmid DNA encoding a malaria vaccine candidate via amino-functionalized poly(GMA-co-EDMA) monolith

Malaria is a global health problem; an effective vaccine is urgently needed. Due to the relative poverty and lack of infrastructure in malaria endemic areas, DNA-based vaccines that are stable at ambient temperatures and easy to formulate have great potential. While attention has been focused mainly on antigen selection, vector design and efficacy assessment, the development of a rapid and commercially viable process to manufacture DNA is generally overlooked. We report here a continuous purification technique employing an optimized stationary adsorbent to allow high-vaccine recovery, low-processing time, and, hence, high-productivity. A 40.0 mL monolithic stationary phase was synthesized and functionalized with amino groups from 2-Chloro-N,N- diethylethylamine hydrochloride for anion-exchange isolation of a plasmid DNA (pDNA) that encodes a malaria vaccine candidate, VR1020-PyMSP4/5. Physical characterization of the monolithic polymer showed a macroporous material with a modal pore diameter of 750 nm. The final vaccine product isolated after 3 min elution was homogeneous supercoiled plasmid with gDNA, RNA and protein levels in keeping with clinical regulatory standards. Toxicological studies of the pVR1020-PyMSP4/5 showed a minimum endotoxin level of 0.28 EU/m.g pDNA. This cost-effective technique is cGMP compatible and highly scalable for the production of DNA-based vaccines in commercial quantities, when such vaccines prove to be effective against malaria. © 2008 American Institute of Chemical Engineers.

Creation of protein loaded biodegradable microparticles via ultrasonic atomization suitable for nasal delivery

Improved biopharmaceutical delivery may be achieved via the use of biodegradable microspheres as delivery vehicles. Biodegradable microspheres offer the advantages of maintaining sustained protein release over time whilst simultaneously protecting the biopharmaceutical from degradation. Particle samples produced by ultrasonic atomization were studied in order to determine a feed stock capable of producing protein loaded poly-ε-caprolactone (PCL) particles suitable for nasal delivery (i.e., less than 20 μm). A 40 kHz atomization system was used with a 6 mm full wave atomization probe. The effect of solids percent, feed flow rate, volumetric ratio of the polymer stock to the protein stock, and protein concentration in the protein stock on particle size characteristics were determined. It was shown that feed stocks containing 100 parts of 0.5 or 1.0% w/v PCL in acetone with one part 100 mg ml -1 BSA and 15 mg ml -1 PVA produced particles with a mass moment diameter (D[4,3]) of 13.17 μm and 9.10 μm, respectively in addition to displaying high protein encapsulation efficiencies of 93 and 95%, respectively. The biodegradable PCL particles were shown to be able to deliver encapsulated protein in vitro under physiological conditions.

Plasmid DNA purification via the use of a dual affinity protein

Methods are presented for the production, affinity purification and analysis of plasmid DNA (pDNA). Batch fermentation is used for the production of the pDNA, and expanded bed chromatography, via the use of a dual affinity glutathione S-transferase (GST) fusion protein, is used for the capture and purification of the pDNA. The protein is composed of GST, which displays affinity for glutathione immobilized to a solid-phase adsorbent, fused to a zinc finger transcription factor, which displays affinity for a target 9-base pair sequence contained within the target pDNA. A Picogreen™ fluorescence assay and/or anx ethidium bromide agarose gel electrophoresis assay can be used to analyze the eluted pDNA.

Multi-action recognition via stochastic modelling of optical flow and gradients

In this paper we propose a novel approach to multi-action recognition that performs joint segmentation and classification. This approach models each action using a Gaussian mixture using robust low-dimensional action features. Segmentation is achieved by performing classification on overlapping temporal windows, which are then merged to produce the final result. This approach is considerably less complicated than previous methods which use dynamic programming or computationally expensive hidden Markov models (HMMs). Initial experiments on a stitched version of the KTH dataset show that the proposed approach achieves an accuracy of 78.3%, outperforming a recent HMM-based approach which obtained 71.2%.

News via Voldemort: Parody accounts in topical discussions on Twitter

Parody accounts are prevalent on Twitter, offering irreverent interpretations of public figures, fictional characters and more. These accounts post comments framed within the context of their fictional universes or stereotypes of their subjects, responding in-character to topical events. This article positions parody accounts as a ritualised social media practice, an extension of fan practices and irreverent Internet culture. By providing a typology of parody accounts and analysing the topicality of selected parody accounts’ tweets, the research examines how these accounts contribute to topical discussions. In-character framing of topical comments allows parody accounts to offer original interpretations of breaking news that receive more attention than their other tweets. The presence and longevity of parody accounts underline the importance of humour on social media, including within news and topical coverage.

Catalytic activity evaluation of industrial Pd/C catalyst via gray-box dynamic modeling and simulation of hydropurification reactor

In this paper, dynamic modeling and simulation of the hydropurification reactor in a purified terephthalic acid production plant has been investigated by gray-box technique to evaluate the catalytic activity of palladium supported on carbon (0.5 wt.% Pd/C) catalyst. The reaction kinetics and catalyst deactivation trend have been modeled by employing artificial neural network (ANN). The network output has been incorporated with the reactor first principle model (FPM). The simulation results reveal that the gray-box model (FPM and ANN) is about 32 percent more accurate than FPM. The model demonstrates that the catalyst is deactivated after eleven months. Moreover, the catalyst lifetime decreases about two and half months in case of 7 percent increase of reactor feed flowrate. It is predicted that 10 percent enhancement of hydrogen flowrate promotes catalyst lifetime at the amount of one month. Additionally, the enhancement of 4-carboxybenzaldehyde concentration in the reactor feed improves CO and benzoic acid synthesis. CO is a poison to the catalyst, and benzoic acid might affect the product quality. The model can be applied into actual working plants to analyze the Pd/C catalyst efficient functioning and the catalytic reactor performance.

Production of biodegradable nano and micro particles via ultrasonic atomization for biopharmaceutical delivery

Biopharmaceuticals have been shown to have low delivery and transformation efficiencies. To over come this, larger doses are administered in order to obtain the desired response which may lead to toxicity and drug resistance. This paper reports upon a continuous particle production method utilizing surface acoustic wave atomization to reliably produce micro and nanoparticles with physical characteristics to facilitate the cellular uptake of biopharmaceuticals. By producing particles of an optimal size for cellular uptake, the efficacy and specificity of drug loaded nanoparticles will be increased. Better delivery methods will result in dosage reduction (hence lower costs per dose), reduced toxicity, and reduced problems associated with multidrug resistance due to over dosing.

The synthesis, characterization, X-ray structure and magnetism of dinuclear-based bis[μ-(1,1,3,3-tetracyano-2-ethoxypropenido-κ2N,N′) (1,1,3,3-tetracyano-2-ethoxypropenido-κN)(2,2′-bipyridine)copper(II)] organized in alternating chains via semi-coordinating Cu–N distances

The monoanionic ligand 1,1,3,3 tetracyano-2 ethoxypropenide (tcnoet) is reported with its Cu(II)–bpy complex of formula [Cu2(µ-tcnoet)2(tcnoet)2(bpy)2]. The structure has been determined using X-ray diffraction and features an alternating chain with bridging tcnoet ligands. One ligand acts as a bidentate, dinucleating ligand with one short Cu–N and one medium Cu–N bond, whereas the other tcnoet is largely monodentate, albeit with a very weak interdimer Cu–N bond. Despite the arrangement in dinuclear units, further arranged into linear chains through the non-bridging tcnoet ligand, the compound shows no significant magnetic exchange, as deduced from magnetic susceptibility down to 4 K. Ligand-field, IR and EPR spectra in the solid state and in frozen solution are reported and are consistent with the overall structure.

Structure evolution characterization of Anyang anthracites via H2O2 oxidization and HF acidification

The structural characteristics of the raw coal (AY), the H2O2 oxidized coals (AY–H2O2) and the HF acidized AY–H2O2 (AY–H2O2–HF) were investigated by SEM, X-ray diffraction, Raman and FTIR spectroscopy. The results indicate that the derivative coals show an obvious increase in the aromaticity, crystalline carbon content and hydroxyl content, especially the AY–H2O2–HF. The stacking layer number of crystalline carbon decreases and the aspect ratio (La/Lc) remarkably increases for AY–H2O2 and AY–H2O2–HF. The crystalline layers become much thinner. The particle size of AY–H2O2–HF in width significantly decreases from 1 μm to less than 100 nm. The combination of H2O2 oxidization and HF acidification is effective to reduce the size of the aromatic layers and to increase the reactivity of derivative coals. The process can help us obtain the superfine crystalline carbon materials like graphite structure.