Microalgal fatty acid composition: Rapid assessment using near-infrared spectroscopy

Walsh, KB ORCiD: 0000-0002-3033-8622The feasibility of assessing microalgal fatty acid composition using near-infrared spectroscopy (NIRS) is described. The chlamydomonad microalga, Rhopalosolen saccatus (previously known as Characium saccatum), was isolated from the Fitzroy River, Central Queensland, Australia. R. saccatus was grown in batch culture with varying phosphorus nutrition and assessed for dry matter, total lipid and fatty acid composition using gas chromatography (GC). Transmission spectra (1100–2500 nm) were acquired of liquid culture, and reflectance spectra were acquired of wet and dry filtrates of cultures and of methyl esters. Partial least square (PLS) regression models were built on biomass, total lipid and a number of fatty acids. All sample presentation models supported PLS regression model with a cross validation correlation coefficient (Rcv) >0.87 for biomass and Rcv >0.68 for total lipid; however, the use of dry filtrates of culture is recommended as the sample presentation mode of choice. Models for fatty acids based on culture transmission spectra, reflectance spectra of wet and dry culture filtrates, or reflectance spectra of methyl esters in solvent were not acceptable. Dry extracts of methyl esters supported adequate models for fatty acids from C8:0 to C22:0, with the exception of capric and behenic acids, with an Rcv of 0.89–0.94; however, in practice, samples processed to this stage can be easily analyzed by GC. Near-infrared spectroscopy can be a potential choice for rapid estimation of biomass (dry matter) and lipid content and composition in microalgae, with further work required to demonstrate oping robustness of the calibration model in prediction of unknown samples. © 2015, Springer Science+Business Media Dordrecht.Associated Grant:Central Queensland Universit

Effects of porosity distribution and porosity volume fraction on the electromechanical properties of 3-3 piezoelectric foams

Unit-cell based finite element models are developed to completely characterize the role of porosity distribution and porosity volume fraction in determining the elastic, dielectric and piezoelectric properties as well as relevant figures of merit of 3-3 type piezoelectric foam structures. Eight classes of foam structures which represent structures with different types and degrees of uniformity of porosity distribution are identified; a Base structure (Class I), two H-type foam structures (Classes II, and III), a Cross-type foam structure (Class IV) and four Line-type foam structures (Classes V, VI, VII, and VIII). Three geometric factors that influence the electromechanical properties are identified: (i) the number of pores per face, pore size and the distance between the pores; (ii) pore orientation with respect to poling direction; (iii) the overall symmetry of the pore distribution with respect to the center of the face of the unit cell. To assess the suitability of these structures for such applications as hydrophones, bone implants, medical imaging and diagnostic devices, five figures of merit are determined via the developed finite element model; the piezoelectric coupling constant (K t), the acoustic impedance (Z), the piezoelectric charge coefficient (d h), the hydrostatic voltage coefficient (g h), and the hydrostatic figure of merit (d h g h). At high material volume fractions, foams with non-uniform Line-type porosity (Classes V and VII) where the pores are preferentially distributed perpendicular to poling direction, are found to exhibit the best combination of desirable piezoelectric figures of merit. For example, at about 50% volume fraction, the d h, g h, and d h g h figures of merit are 55%, 1600% and 2500% higher, respectively, for Classes V and VII of Line-like foam structures compared with the Base structure

Innovative approaches to genome editing in avian species

Abstract The tools available for genome engineering have significantly improved over the last 5 years, allowing scientist to make precise edits to the genome. Along with the development of these new genome editing tools has come advancements in technologies used to deliver them. In mammals genome engineering tools are typically delivered into in vitro fertilized single cell embryos which are subsequently cultured and then implanted into a recipient animal. In avian species this is not possible, so other methods have been developed for genome engineering in birds. The most common involves in vitro culturing of primordial germ cells (PGCs), which are cells that migrate through the embryonic circulatory system to the developing gonad and colonize the gonad, eventually differentiating into the gonadocytes which produce either sperm or ova. While in culture the PGCs can be modified to carry novel transgenes or gene edits, the population can be screened and enriched, and then transferred into a recipient embryo. The largest drawback of PGC culture is that culture methods do not transfer well across avian species, thus there are reliable culture methods for only a few species including the chicken. Two newer technologies that appear to be more easily adapted in a wider range of avian species are direct injection and sperm transfection assisted gene editing (STAGE). The direct injection method involves injecting genome engineering tools into the circulatory system of the developing embryo just prior to the developmental time point when the PGCs are migrating to the gonads. The genome engineering tools are complexed with transfection reagents, allowing for in vivo transfection of the PGCs. STAGE utilizes sperm transfection to deliver genome engineering tools directly to the newly fertilized embryo. Preliminary evidence indicates that both methodologies have the potential to be adapted for use in birds species other than the chicken, however further work is needed in this area

Channel Scheduling Algorithms using Burst Segmentation and FDLs for Optical Burst-Switched Networks

Abstract – Optical burst switching is a promising solution for terabit transmission of IP data bursts over WDM networks. One of the key components in the design of optical burst-switched nodes is the development of channel scheduling algorithms that can efficiently handle data burst contentions. Currently, traditional scheduling techniques use wavelength conversion and buffering to resolve burst contention. In this paper, we reduce packet losses by proposing a number of data channel scheduling algorithms that use burst segmentation and fiber delay lines (FDLs). The proposed scheduling algorithms are classified based on the placement of the FDL buffers in the optical burst-switched node and are referred to as delay-first or segment-first schemes. Simulation results show that these algorithms can effectively reduce the packet loss probability compared to existing scheduling techniques. I

Towards Pattern-based Reliability Certification of Services

Abstract. On Service-Oriented Architectures (SOAs), the mechanism for run-time discovery and selection of services may conflict with the need to make sure that business process instances satisfy their reliability requirements. In this paper we describe a certification scheme based on machine-readable reliability certificates that will enable run-time negotiation. Service reliability is afforded by means of reliability patterns. Our certificates describe the reliability mechanism implemented by a service and the reliability pattern used to implement such a mechanism. Digital signature is used to associate the reliability claim contained in each certificate with the party (service supplier or accredited third-party) taking responsibility for it.