Replacement of RNA hairpins by in vitro selected tetranucleotides

An in vitro selection method based on the autolytic cleavage of yeast tRNAPhe by Pb2+ was applied to obtain tRNA derivatives with the anticodon hairpin replaced by four single-stranded nucleotides. Based on the rates of the site-specific cleavage by Pb2+ and the presence of a specific UV-induced crosslink, certain tetranucieotide sequences allow proper folding of the rest of the tRNA molecule, wheras others do not. One such successful tetramer sequence was also used to replace the acceptor stem of yeast tRNAPhe and the anticodon hairpin of E.coli tRNAPhe without disrupting folding. These experiments suggest that certain tetramers may be able to replace structurally non essential hairpins in any RNA.

Islamic gardens between restoration and replacement

Architecture is considered the visible reflection of the local character of contexts. Therefore, conserving the architectural heritage is becoming one of the critical concepts in life, especially with the rapid change and transformation characterizing the globalization era. As a vital part of the broader context of the architecture; landscape architecture is also considered an effective tool of societies’ self representation. Gardens reflect a very special relationship between the man and nature and represent the history of the state of societies in which they were developed. Islamic gardens are one of the historic gardens having a special charm of their own. Gardens associated with Islamic period over several hundred years, are designed according to certain ideological principles employing certain physical elements shown in the west as well as the east. They represent an ideological continuity which is unique in its spread and development over a wide range of geographical and cultural regions. The Islamic architectural heritage is usually well protected. In the restoration process, the historic buildings are returned back to their original conditions. However, with the changing nature of gardens; it is sometimes hard to track back their original state. In that case, in order to conserve those gardens; it is important to study the design principles upon which the physical elements were chosen. In this paper, the principles of design of the original Islamic gardens will be reviewed through a quantitative analysis of a questionnaire. These principles will be compared to the current situation of the garden of Humayun’s Tomb built in the Mughal era in India, after its conservation in 2003.

Chromate replacement in coatings for corrosion protection of aerospace aluminium alloys

Mixed rare earth organophosphates have been investigated as potential corrosion inhibitors for AA2024-T3 with the aim of replacing chromate-based technologies. Cerium diphenyl phosphate (Ce(dpp) 3) and mischmetal diphenyl phosphate (Mm(dpp) 3) were added to epoxy coatings applied to AA2024-T3 panels and they were effective in reducing the amount and rate of filiform corrosion in high humidity conditions. Ce(dpp) 3 was the most effective and characterisation of the coating formulations showed approximately a factor of 5 reduction in both the number of corrosion filaments initiated as well as the length of these. Mm(dpp) 3 appeared to reduce the corrosion growth rate by a factor of 2 although it was the more effective inhibitor in solution studies. Spectroscopic characterisation of the coatings indicated that the cerium based inhibitor may disrupt network formation in the epoxy thus resulting in a coating that absorbed more water and allowed greater solubilisation of the corrosion inhibiting compound.

A potential copper-regulatory role for cytosolic expression of the DNA repair protein XRCC5

Copper (Cu) has a critical role in the generation of oxidative stress during neurodegeneration and cancer. Reactive oxygen species generated through abnormal elevation or deficiency of Cu can lead to lipid, protein, and DNA damage. Oxidation of DNA can induce strand breaks and is associated with altered cell fate including transformation or death. DNA repair is mediated through the action of the multimeric DNA-PK repair complex. The components of this complex are the Ku autoantigens, XRCC5 and XRCC6 (Ku80 and Ku70, respectively). How this repair complex responds to perturbed Cu homeostasis and Cu-mediated oxidative stress has not been investigated. We previously reported that XRCC5 expression is altered in response to cellular Cu levels, with low Cu inhibiting XRCC5 expression and high Cu levels enhancing expression. In this study we further investigated the interaction between XRCC5 and Cu. We report that cytosolic XRCC5 is increased in response to Cu, but not zinc, iron, or nickel, and the level of cytosolic XRCC5 correlates with protection against oxidative damage to DNA. These observations were made in both HeLa cells and fibroblasts. Cytosolic XRCC5 interacted with the Cu chaperone and detoxification protein human Atox1 homologue (HAH), and down regulation of XRCC5 expression using siRNA led to enhanced HAH expression when cells were exposed to Cu. XRCC5 could also be purified from cytosolic extracts using a Cu-loaded column. These findings provide further evidence that cytosolic XRCC5 has a key role in protection against DNA oxidation from Cu, through either direct sequestration or signaling through other Cu-detoxification molecules. Our findings have important implications for the development of therapeutic treatments targeting Cu in neurodegeneration and/or cancer.

Fish oil replacement in rainbow trout diets and total dietary PUFA content : II) Effects on fatty acid metabolism and in vivo fatty acid bioconversion

This study aimed to gain a better understanding of the metabolic fate of dietary fatty acids in rainbow trout, with a specific focus on the effect of varying total C18 PUFA level. Fish were fed a control fish oil based diet or one of five experimental fish oil deprived diets formulated with a constant 1/1 ratio of 18:3n-3/18:2n-6 and varying total C18 PUFA levels for a period of 7 weeks. The transcriptional changes of the Δ-6 desaturase and elongase enzymes in direct comparison to in vivo fatty acid bioconversion, estimated using the whole-body fatty acid balance method, were analysed. The main findings were that i) the efficiency of Δ-6 desaturase was negatively affected by C18 PUFA availability, but the total apparent in vivo enzyme activity was directly proportional to C18 PUFA substrate availability; ii) Δ-6 desaturase had a greater affinity towards n-3PUFA than n-6PUFA; iii) excessive C18 PUFA substrate availability could limit the availability of Δ-6 desaturase to act on C24 fatty acid; iv) the elimination of dietary n-3LC-PUFA (enzyme products) up-regulated the transcription rate of Δ-6 desaturase; but v) the total apparent in vivo enzyme activity was directly and positively affected by substrate availability, and not product presence/absence nor the extent of the enzyme transcription rate.

A flexible receiver-driven cache replacement scheme for continuous media objects in best-effort networks

In this paper, we investigate the potential of caching to improve quality of reception (QoR) in the context of continuous media applications over best-effort networks. Specifically, we investigate the influence of parameters such as loss rate, jitter, delay and area in determining a proxy's cache contents. We propose the use of a flexible cost function in caching algorithms and develop a framework for benchmarking continuous media caching algorithms. The cost function incorporates parameters in which, an administrator and or a client can tune to influence a proxy's cache. Traditional caching systems typically base decisions around static schemes that do not take into account the interest of their receiver pool. Based on the flexible cost function, an improvised Greedy Dual (GD) algorithm called GD-multi has been developed for layered multiresolution multimedia streams. The effectiveness of the proposed scheme is evaluated by simulation-based performance studies. Performance of several caching schemes are evaluated and compared with those of the proposed scheme. Our empirical results indicate GD-multi performs well despite employing a generalized caching policy.

Injection, detection and repair of aesthetics in home movies

This paper details the design of an algorithm for automatically manipulating the important aesthetic element of video, visual tempo. Automatic injection, detection and repair of such aesthetic elements, it is argued, is vital to the next generation of amateur multimedia authoring tools. We evaluate the performance of the algorithm on a battery of synthetic data and demonstrate its ability to return the visual tempo of the final media a considerable degree closer to the target signal. The novelty of this work lies chiefly in the systematic manipulation of this high level aesthetic element of video.

Arthroscopic repair of humeral avulsion of glenohumeral ligament lesion : anterior and posterior techniques

Humeral avulsion of the inferior glenohumeral ligament complex is an unusual pathology, often implicated in traumatic shoulder instability. Traditional open techniques involve at least partial detachment of the subscapularis, and arthroscopic techniques are limited by neurovascular boundaries. The technique described here presents an anterior and posterior arthroscopic approach that can be used individually or in combination to treat different types of humeral avulsion of the inferior glenohumeral ligament lesions. The anterior approach is based on anatomic guidelines described in the literature. The posterior approach is based on the arthroscopic and cadaveric anatomic studies described by one of the authors (D.N.B.); use of the recently described axillary pouch portal (Bhatia portal) permits safe arthroscopic instrumentation access in the entire inferior glenohumeral recess and provides adequate access to the posteroinferior aspect of the humeral head. The differential mattress stitch technique ensures secure fixation of the avulsed ligaments and eliminates excessive capsular redundancy. Technical tips to avoid complications are discussed, and a detailed rehabilitation protocol is presented.