Human complement factor I: its expression by insect cells and its biochemical and structural characterisation

Factor I is a five-domain plasma serine protease which is essential for the regulation of the complement system. In order to express this, the factor I coding sequence was cloned into a recombinant baculovirus system, which was used to infect Trichoplusia ni cells. Using the native factor I leader sequence, recombinant factor I (rFI) was secreted into the culture medium. Purified rFI was recognised by polyclonal antisera and by the factor I-specific monoclonal antibody MRC-OX21. SDS PAGE showed that rFI was processed into two chains with molecular weights of 48,000 and 36,000. Amino acid sequence analysis showed that the N-terminal sequences of the rFI chains were the same as those of serum-derived factor I (sFI), confirming that processing was correct. Since both molecular weights were less than those observed for sFI, this is attributed to the replacement of complex-type oligosaccharides by high mannose ones in rFI. C3(NH,) cleavage assays showed that rFI had 55% the activity of sFI. Circular dichroism and Fourier transform infrared spectroscopy showed that the protein folding of rFI and sFI were very similar. Both had a secondary structure low in alpha-helix and high in beta-sheet, as expected from crystal structure and multiple sequence alignment analyses. It is inferred that the reduced activity of rFI is attributable to its changed glycosylation. The availability of rFI and structures for the domains in factor I makes possible new approaches to determine the molecular basis of its interactions with factor H and C3b.     

Withdrawal of pairs of threaded rods with small edge distances and spacings

An experimental investigation on withdrawal of pairs of screwed-in threaded rods embedded in glued-laminated timber elements is presented in this paper. Specimens with varying angles between the rod axis and the grain direction (α?=?15°, 30°, 60°, 90°) and 2 different configurations with respect to edge distances and spacings were tested. The diameter and the embedment length of the rods were 20 and 450 mm, respectively. The threaded rods were embedded in a row perpendicular to the plain of the grain. The edge distances and spacings were smaller than the minimum requirements according to Eurocode 5. The withdrawal capacity of pairs of rods was compared to the withdrawal capacity of single rods and the effective number, n _ef , was found to be in the range 1.72–1.94, despite the small edge distances and spacings. Based on the experimental results obtained, a simple approximating expression was derived for n _ef . An analytical model based on Volkersen theory with an idealized bi-linear constitutive relationship was used to estimate the withdrawal capacity and stiffness. The analytical estimations were in good agreement with the experimental results. Finally, the withdrawal stiffness was estimated by use of finite element simulations. The numerical estimations for the withdrawal stiffness were also in good agreement with the experimental results.     

A methodology for validating the renewable energy data in EU

The multidimensional character of renewable energy sources (RES) necessitates the collection of a number of related data in order to support EU policy needs. Apart from the technology and techno-physical data also socioeconomic (e.g. employment, turnover) data and R&D expenditures are of critical relevance. The monitoring of the above RES data with respect to the existing targets for RES is of significant importance. In addition to this, even though significant data gathering efforts have been implemented, a lot of fragmented data and deduced findings are currently available, which sometimes lack consistency and verification. As a result, RES data validation and completion capacity is needed in the framework of the European Union (EU) energy policy. In addition to this, agreed and validated RES data can help energy policy makers and relevant stakeholders answering to pressing energy socio-economics’ and sustainability issues. In this context, the main aim of the paper is to present a reference methodology for validating the RES Data in the EU. The development of the methodology is mainly based on the review of existing methods and ends up with recommendations for improvements in RES data aggregation and statistical interpretation, taking into consideration the related analysis of statisticians, energy technology experts and energy socio-economists.     

Study of performance parameter optimisation of resorption cogeneration utilising heat and mass recovery

In the present scenario, one of the global issues is energy crisis, and it is found that effective utilisation of low-grade waste heat energy as potential solution to this crisis, which could be easily used with the cogeneration plant. In this work, an attempt is made to implement a mass and heat recovery system with a basic resorption cogeneration unit. Low-grade solar energy is utilised by the expansion machine and ammonia resorption unit, and the plant produces a dual output of cooling effect and electricity. The problem of variation reaction rate is sorted out by introducing a buffer prior to the expansion machine; similarly, the deficiency of chemisorption is overcome by a pair of resorption cycles. Under various operating conditions, six resorption pairs were analysed and it was found that the SrCl₂–MnCl₂ pair to be the best pair. Exergy analyses were made using the equation solver.     

How Successful are Energy Efficiency Investments? A Comparative Analysis for Classification & Performance Prediction

Computational Economics - Increasing the financial institutions’ deployment of capital in energy efficiency investments remains still a challenge. The present article is intended to...     

Effect of Copper and Zirconium Addition on Properties of Fe-Co-Si-B-Nb Bulk Metallic Glasses

In this research work, iron-based bulk metallic glasses (BMGs) have been fabricated, characterized and compared with Fe-Si alloy. BMG alloys of composition ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄) were synthesized by suction casting technique using chilled copper die. Effect of copper and zirconium addition on magnetic, mechanical, thermal and electrochemical behavior of ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄ BMGs was investigated. Furthermore, effect of annealing on nano-crystallization and subsequently on magnetic and mechanical behavior was also analyzed. Amorphousness of structure was evidenced by XRD analysis and microscopic visualization, whereas nano-crystallization behavior was identified by peak broadening of XRD patterns. Magnetic properties, measured by vibrating sample magnetometer, were found to be improved for as-cast BMG alloys by copper addition and further enhanced by nano-crystallization after annealing. Mechanical properties were observed to be increased by zirconium addition while slightly declined by copper addition. Potentiodynamic polarization analysis manifested the positive role of zirconium in enhancing corrosion resistance of BMGs in acidic, basic and brine mediums. Moreover, mechanical properties and corrosion analysis results affirmed the superiority of BMG alloys over Fe-Si alloy.     

Preliminary study on the fabrication of aluminium foam through pressure assisted sintering dissolution process

This paper discusses the improvement made by pressure assisted sintering dissolution process (PASDP) as opposed to the solid-state sintering dissolution process (SSSDP) which was used in producing a much improved open celled aluminium foam. The improvements leads to an aluminium foam possessing a high dense of cell wall which is attainable in a much shorter time and possesses superior mechanical properties. By varying the local sodium chloride (NaCl) volume fractions in the sodium chloride/aluminium (NaCl/Al) compact, it is possible to fabricate aluminium foam with different relative densities. When subjected to monotonic compression mode, the fabricated aluminium foam exhibits typical stress–strain behaviour of metallic foam. The principles of Taguchi's Design of Experiments were employed to optimize processing factors for the fabrication of aluminium foam. Results were analysed based on Taguchi's signal to noise ratio (S/N) and analysis of variance (ANOVA) techniques in order to obtain the optimum combination of process parameter settings. Results indicate that the most notable factor influencing the fabrication of Al foam was the compaction at elevated temperature, followed by temperature, time and the process heating rate. The optimum processing parameters for the PASDP process were then predicted based on these results.     

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.