Comparative gamma radiation sensitivity of Tribolium madens (Charpentier) and T. castaneum (Herbst)

The effects of gamma radiation doses between 5 and 100 krad on all metamorphic stages of Tribolium madens and T. castaneum were studied. Results from the two species were similar although T. madens appeared to be more radiosensitive. The development of adults from treated eggs and larvae was prevented by 5 krad in T. madens and by 10 krad in T. castaneum. Some adults emerged from treated pupae at all treatment levels, but no reproduction occurred at 20 krad or above. Adult females of both species were more sensitive to the sterilizing effects of gamma radiation than were males, but sterility of both sexes was effected at doses of 30 krad and above. Control of these two species appears feasible with levels of radiation currently approved for treatment of stored-grain insects in wheat and wheat flour.     

Evaluation of detergent extraction procedures for characterising carbohydrate components in ruminant feeds and digesta

Steers fitted with simple rumen and abomasal cannulas were given isoenergetic diets of approximately equal amounts of untreated (UT) barley straw and concentrates (flaked maize + tapioca) alone (BS) or with urea (BSU) or fishmeal (BSF). Similar diets were also given in which the barley straw had been treated (AT) with NaOH (BSA, BSAU and BSAF respectively). The diets were given in a 6 × 6 Latin square design. Feed components and abomasal digesta samples were analysed for neutral (NDF) and acid (ADF) detergent fibres and for monosaccharide constituents of structural polysaccharides. Hemicellulose contents were estimated as the sum of xylose + arabinose (X + A) and by the difference between ash-free NDF and ash-free ADF (NDF-ADF). Cellulose was estimated as β-linked glucose (C) and by the difference between ash-free ADF and lignin (ADF–L).¹⁰³ Ruthenium and PEG were given as flow markers and flows (g24h^?1) at the abomasum of carbohydrate components estimated in these ways were calculated. Approximately 98% (by wt.) of the cellulose (C) found in original feed and digesta samples was recovered in both NDF and ADF. Recoveries of hemicellulose (X + A) in NDF from UT straw, AT straw and abomasal digesta were approximately 92, 48 and 50%, respectively. The ADF fraction of feeds and digesta contained 3–6 and 10–17% of the nitrogen and xylose, respectively, present in the original samples. Mouth to abomasum digestibilities of hemicellulose (NDF– ADF) for diets BS, BSU, BSF, BSA, BSAU and BSAF were 39, 62, 67, 29, 61 and 76%, respectively. Corresponding values for cellulose (ADF–L) were 37, 34, 50, 45, 48, and 63%, respectively. The use of NDF–ADF and ADF–L as measures of hemicellulose and cellulose contents, respectively, of feeds and digesta, and the digestibility of these carbohydrate fractions between mouth and abomasum of steers are discussed.     

Introduction of sulphydryl groups into pea vicilin: Formation of intra-and inter-polypeptide disulphide bonds

Site directed mutagenesis was used to introduce two cysteine residues into the hydrophilic regions of the pea vichlin polypeptide previously expressed in Saccharomyces cerevisiae. The mutated polypeptide was expresed and the resultant protein was characterised by sodium dodecyl sulphatepolyacrylamide gel electrophoresis. The presence of both intra- and inter-polypeptide sulphydryl bonds was indicated by bands of different mobility from those of the native polypeptide. The association of mutated vicili polypeptides into disulphide-bonded aggregates within the yeast was not a random process, trimers being the major aggregate produced. When the mutated vicilin was extracted from yeast and purified, random aggregates of the vicilin polypeptide were formed.     

Focusing on business projects as an area for future research: An exploratory discussion of four different perspectives

An important development in project management in recent years has been the emergence of a new class of projects, in areas such as organisational change and IT, integrated business solutions, and long-term public service delivery. Often referred to as ‘business projects’, this new class of projects (and programmes) reflects a growing conceptual shift away from the traditional engineering view of projects, towards a more business-oriented view, in which the primary concern is no longer the capital asset, system or facility etc, but increasingly the challenge of implementing business strategy, improving organisational effectiveness, and managing the realisation of stakeholder benefits. Drawing on recent research from the UK Government-funded Rethinking Project Management Network, this paper argues that future research in this area needs to look beyond the mainstream literature on project management, to other relevant disciplines such as strategic management, operations management, and the management of change. Against this background, the authors present four conceptual perspectives from the management literature, which can be usefully applied to business projects. They represent exploratory contributions from four participants in the Network – a special collaboration between researchers – whose ideas and perspectives were either discussed at the Network meetings, or are the subject of research elsewhere. Collectively, the four contributions represent an exploratory discussion of different theoretical perspectives, in order to inform and stimulate other researchers and practitioners working in the field.     

Design and facile production of recombinant resilin-like polypeptides: gene construction and a rapid protein purification method

Resilin is an elastic protein found in specialized regions of the cuticle of insects, which displays unique resilience and fatigue lifetime properties. As is the case with many elastomeric proteins, including elastin, gliadin and spider silks, resilin contains distinct repetitive domains that appear to confer elastic properties to the protein. Recent work within our laboratory has demonstrated that cloning and expression of exon 1 of the Drosophila melanogaster CG15920 gene, encoding a putative resilin-like protein, results in a recombinant protein that can be photochemically crosslinked to form a highly resilient, elastic biomaterial (Rec1 resilin). The current study describes a recursive cloning strategy for generating synthetic genes encoding multiple copies of consensus polypeptides, based on the repetitive domains within resilin-like genes from D. melanogaster and Anopheles gambiae. A simple non-chromatographic purification method that can be applied to these synthetic proteins and Rec1 is also reported. These methods for the design and purification of resilin-like periodic polypeptides will facilitate the future investigation of structural and functional properties of resilin, and the development of novel highly resilient biomaterials.     

The bone morphogenetic protein 15 gene is X-linked and expressed in oocytes

We have taken advantage of the sequence relationships among the bone morphogenetic proteins (BMPs) to identify the mouse Bmp15 and human BMP15 genes. The 392-amino acid prepropeptides encoded by these BMP genes exhibit significant homology to each other, although the 70% identity observed between the 125-amino acid mature peptides is considerably lower than that seen in comparisons of other mouse and human orthologs. Both genes share a common structural organization and encode mature peptides that lack the cysteine residue normally involved in the formation of a covalent dimer. In addition, mouse Bmp15 and human BMP15 map to conserved syntenic regions on the X chromosome. We demonstrate, through a combination of Northern blot and in situ hybridization analyses, that mouse Bmp15 is expressed specifically in the oocyte beginning at the one-layer primary follicle stage and continuing through ovulation. Interestingly, BMP-15 is most closely related to and shares a coincident expression pattern with the mouse growth/differentiation factor 9 (GDF-9) gene that is essential for female fertility. Our findings will be important for defining the role of BMP-15 in follicular development.     

Damage advancement behavior in braided composite structures for mini aerial vehicles

This work provides a systematic approach to accurately predict damage progression in a composite structure subjected to bending load. Landing gear structures for unmanned aerial vehicles were fabricated from braided textile preforms and assessed for flexural behavior. A multiscale finite element analysis model was developed for analyzing the progressive damage of these structures under bending loads. Microscale and mesoscale analyses were carried out first. Subsequently, the results of microscale and mesoscale analyses were used as inputs in macroscale analyses that predicted the progressive damages in the entire landing gear structure. The numerical results were validated by experimental studies.     

Functionalization of wood particles through a reactive extrusion process

Wood particles were modified in a reactive extrusion process with maleated polyethylene (MAPE) and maleated polypropylene (MAPP) compounds. Contents of MAPE were varied to study the effect of material composition on grafting efficiency during reactive extrusion, while extruder barrel temperatures and rotational screw speeds were varied to evaluate the effects of processing conditions on the modification of wood particles. Polymer molecular weight effects were followed using MAPP, with different molecular weights. Efficiency of the modification was assessed using FTIR and XPS surface analysis techniques, along with a titrimetric analysis, to verify the esterification reaction between the wood particles and maleated polyolefins. The grafting of maleated polyolefins onto the surface of the wood particles through a reaction of the hydroxyl groups on the wood surface with the maleated groups of the maleated polyolefins was confirmed, while the level of grafting of MAPE onto wood particles was determined to be a function of the MAPE concentration. However, there was no significant difference found in grafting efficiency at different extrusion processing conditions, rather all of the conditions resulted in adequate grafting. Similarly, there was no difference in grafting efficiency with the molecular weight of MAPP. Reactive extrusion was found to be a suitable technique for the modification of wood particles, with maleated polyolefins, for all of the material compositions and processing conditions studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3131–3142, 2006     

The Advanced Energy Initiative

The President's Advanced Energy Initiative (AEI), launched in 2006, addresses the challenges of energy supply and demand facing our Nation by supporting research and development of advanced technologies for transportation and stationary power generation. The AEI portfolio includes clean coal, nuclear and renewable energy technologies (solar and wind) for stationary power generation and advanced battery technologies, cellulosic ethanol as a fuel and hydrogen fuel cells for transportation. These research and development programs are underpinned by comprehensive life-cycle analysis efforts using models such as Hydrogen Analysis (H2A) and Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) to enable a better understanding of the characteristics and trade-offs associated with advanced energy options and to help decision makers choose viable pathways for clean, reliable and affordable energy.     

The effect of few historical data on the performance of sample average approximation method for operating room scheduling

We model the scheduling problem of a single operating room for outpatient surgery, with uncertain case durations and an objective function comprising waiting time, idle time, and overtime costs. This stochastic scheduling problem has been studied in diverse forms. One of the most common approaches used is the sample average approximation (SAA). Our contribution is to study the use of SAA to solve this problem under few historical data using families of log t distributions with varying degrees of freedom. We analyze the results of the SAA method in terms of optimality convergence, the effect of the number of scenarios, and average computational time. Given the case sequence, computational results demonstrate that SAA with an adequate number of scenarios performs close to the exact method. For example, we find that the optimality gap, in units of proportional weighted time, is relatively small when 500 scenarios are used: 99% of the instances have an optimality gap of less than 2.6 7% (1.74%, 1.23%) when there are 3 (9, many) historical samples. Increasing the number of SAA scenarios improves performance, but is not critical when the case sequence is given. However, choosing the number of SAA scenarios becomes critical when the same method is used to choose among sequencing heuristics when there are few historical data. For example, when there are only three (nine, many) historical samples, 99% of the instances have less than 25.38% (13.15%, 6.87%) penalty in using SAA with 500 scenarios to choose the best sequencing heuristic.