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X-ray micro-computed tomography (μCT) is a technique which can obtain three-dimensional images of a sample, including its internal structure, without the need for destructive sectioning. Here, we review the capability of the technique and examine its potential to provide novel insights into the lifestyles of parasites embedded within host tissue. The current capabilities and limitations of the technology in producing contrast in soft tissues are discussed, as well as the potential solutions for parasitologists looking to apply this technique. We present example images of the mouse whipworm Trichuris muris and discuss the application of μCT to provide unique insights into parasite behaviour and pathology, which are inaccessible to other imaging modalities.
Two highly pathogenic avian influenza (HPAI) outbreaks have affected commercial egg production flocks in the American continent in recent years; a H7N3 outbreak in Mexico in 2012 that caused 70% to 85% mortality and a H5N2 outbreak in the United States in 2015 with over 99% mortality. Blood samples were obtained from survivors of each outbreak and from age and genetics matched non-affected controls. A total of 485 individuals (survivors and controls) were genotyped with a 600 k single nucleotide polymorphism (SNP) array to detect genomic regions that influenced the outcome of highly pathogenic influenza infection in the two outbreaks. A total of 420458 high quality, segregating SNPs were identified across all samples. Genetic differences between survivors and controls were analyzed using a logistic model, mixed models and a Bayesian variable selection approach. Several genomic regions potentially associated with resistance to HPAI were identified, after performing multidimensional scaling and adjustment for multiple testing. Analysis conducted within each outbreak identified different genomic regions for resistance to the two virus strains. The strongest signals for the Iowa H5N2 survivor samples were detected on chromosomes 1, 7, 9 and 15. Positional candidate genes were mainly coding for plasma membrane proteins with receptor activity and were also involved in immune response. Three regions with the strongest signal for the Mexico H7N3 samples were located on chromosomes 1 and 5. Neuronal cell surface, signal transduction and immune response proteins coding genes were located in the close proximity of these regions.
The effects of shape and thickness of a tin surface layer and of the energy of a 170 ps neodymium:yttrium-aluminum-garnet laser pulse on the conversion efficiency (CE) into extreme ultraviolet emission in the 13.5 nm region is investigated. Whereas a CE of up to 1.16% into the 2% reflection band of multilayer Mo/Si optics was measured for a bulk Sn target at a laser energy of 25 mJ, significant CE enhancement up to 1.49% is demonstrated for a 200-nm-thick Sn layer on a microstructured porous alumina substrate.
We have successfully demonstrated optical aperture synthesis at the 4-m Anglo-Australian Telescope. By using a multi-hole mask over the (re-imaged) primary mirror and recording the resulting fringe patterns with high time resolution, diffraction-limited images of sufficiently bright objects can be reconstructed. The data processing uses closure phases to overcome the effects of atmospheric turbulence. We show an image of the double star η Oph, with component separation 0″.45.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
Obesity has origins extending to antenatal and early postnatal periods; however, the relationship between early postnatal diet and subsequent obesity is not well defined. The aims of this study were to determine whether early childhood dietary quality was associated with (a) infant and adolescent nutrition and (b) body mass index (BMI) in childhood and adolescence. The degree to which early nutrition and growth factors determine BMI throughout childhood and adolescence was also explored. This research was conducted using the Raine Study, a longitudinal survey of Australian children assessed from mid-gestation to 17 years of age. A dietary quality index, the Raine Eating Assessment in Toddler score, was assigned to 2562 participants to assess early nutrition. Linear regression determined that breastfeeding was associated with dietary quality at 1–3 years. Dietary elements at 14 years of age were related to earlier dietary quality. There were no consistent associations between early diet and BMI at 3, 5, 8, 10, 14 or 17 years. In contrast, birth weight and infant weight gain were significantly associated with BMI at these ages. This study suggests that early dietary patterns are associated with aspects of diet in adolescence, likely reflecting the influence of maternal reporting. Birth weight and early growth appear to be more important determinants of adolescent BMI than early diet and nutrition. While optimizing early diet by maternal nutritional education has potential to influence later nutrition, interventions focussing on early weight gain may have a greater impact on the obesity epidemic.
In order to understand thickness and interfacial effects on the
crystallization kinetics of amorphous solids, Ni(P) thin films electrolessly
deposited on Cu seed layers were annealed at constant heating rates or at
constant temperatures in a DSC to obtain activation energies andAvrami
exponents. It was found that the activation energy of crystallization in
Ni(P) changes asa function of sample thickness when the sample thickness is
less than 1.0 μm. Furthermore, the Avrami exponent was found to change not
only as a function of thickness but also as a function of annealing
In this paper the new technique of ultraviolet-assisted injection liquid source (UVILS) chemical vapour deposition (CVD) of thin tantalum pentoxide films on p-type Si (100) wafers is presented. This method involves the use of a krypton chloride (KrCl*) excimer lamp, radiating at 222 nm, and a novel injection liquid source capable of delivering precisely controllable quantities of a novel high-volatility liquid metalorganic precursor into the CVD chamber. The physical and chemical properties of the films formed have been studied using spectroscopic ellipsometry and Fourier transform infrared spectroscopy measurements while the electrical properties of the films were determined by surface charge analysis, capacitancevoltage, and current-voltage measurements. Simple metal/oxide/silicon capacitor structures incorporating this tantalum pentoxide have been fabricated. Refractive index values of 2.09±0.07, dielectric constant values of 18-24, fixed oxide charge content of < 1 × 1011 cm−2 and breakdown fields higher than 2 MV/cm can be readily obtained in the as-deposited films.
We have performed 2D and quasi-3D numerical simulations of physical vapor deposition (PVD) into high aspect ratio trenches and vias used for modem VLSI interconnects. The topographic evolution is modeled using (continuum) level set methods. The level set approach is a powerful computational technique for accurately tracking moving interfaces or boundaries, where the advancing front is embedded as the zero level set (isosurface) of a higher dimensional mathematical function. First, we study the 2D case of long rectangular trenches including 3D out-of-plane target flux. The 3D flux is obtained from molecular dynamics computations for AI(100), and hence our approach represents a hybrid atomistic/continuum model. We obtain good agreement with X-TEM data. Secondly, we report results of axisymmetric 3D simulations of high aspect ratio vias which we then go on to compare with experimental data for Ti/TiN barrier layers. We find that the simulation data (using the cosine angular distribution) overpredict bottom coverage in some cases by approximately 20%-30% for both collimated and uncollimated deposition but in other cases provide a reasonably accurate comparison with experiment.
We present experimental results directed at understanding the growth and structure of metallic barrier layer and interconnect films. Numerical simulation results associated with this experimental work are presented in an accompanying paper in these proceedings. Here, thin films of Al, Ti, Cu and Ta have been grown by magnetron sputtering onto oxidized Si substrates. Using a specially-constructed substrate holder, the orientation of the substrate with respect to the growth direction was varied from horizontal to vertical. Films were grown at both low and high argon pressure; in the case of Ta, the cathode power was varied as well. The film structure and in particular the surface roughness was measured by X-ray reflectance and also by atomic force microscopy. We find that the surface roughness increases markedly with orientation angle in the case of Ta and Cu films, and in Ti films grown at high argon pressure. At low pressure, however, the Ti film surface roughness remains constant for all substrate orientations. No variation in roughness with either orientation angle or argon pressure was observed in the Al films. These results suggest that, under certain circumstances, shadowing effects and/or grain orientation (i.e., texture) competition during growth can give rise to lower density, more porous (and thus more rough) films, particularly at large orientation angles, as on sidewalls in sub-micron trenches.
Electrodeposition through photoresist masks is a critical, enabling technology for fabrication of the thick structures (of up to several hundred microns) involved in HI-MEMS. Process integration is an important issue in HI-MEMS. The electrodeposited structure is influenced by the choice of optical or X-ray lithography. Thickness uniformity of the deposit on the wafer scale can be optimized by the use of an auxiliary cathode. On the device or feature scales, thickness uniformity can be improved by the thoughtful design of the pattern to be plated.
A variable reluctance, planar, integrated mini-motor with a 6 mm diameter rotor has been fabricated using lithography, electrodeposition and dielectric planarization processes. The rotors were fabricated separately, released from the substrate, and slipped on the shaft, which was plated up as part of the stator fabrication.