2,141 research outputs found
The optimisation of shot peen forming processes
Get PDFAn optimisation method based on an effective process model is presented. The calibrated and verified process model simulates peening on realistic components and provides a non-linear relationship between peening parameters and deflections. An optimal solution can be found by minimising the deviation of the computed deformed shape from the desired shape subject to certain constraints. This optimal solution of peening parameters can be directly used for practical operations. An optimisation example for forming a cylindrical shape on a 76x76x3 mm sample is provided. The experimental results demonstrate the applicability of the present optimisation method
Trust is a Process
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The paper briefly overviews the growing literature on ātrustā and proposes a new definition. The authors define Trust as a process, as a verb, as action that enables the individual to be pro active in improving relationships. The Relationship Audit is described as a tested aid to monitor different aspects of working with others inside and outside the organisation
Choices and Responsibilities: A Human Centric Approach to University-Industry Knowledge Transfer
Get PDFThe paper reflects on the growing complexities of management education in which business practitioners invite selected academic institutions to develop partnerships for resolving practical challenges and equipping those in the workplace to make more reflective and enlightened choices. European examples from Cambridge and Nottingham illustrate that successful industry and academic collaborations embody long-established themes of mentor-mentee, master-learner relationships. This human centric approach yields personal characteristics for reflective practitioners which enhance innovation, productivity and reputation building. The examples presented in this paper are then placed in a broader university ā industry knowledge transfer context, using a so-called ābow tieā model.
The authors believe that by shifting the attention from processes to people, from productivity to individual and collective growth and maturity, and by starting to apply the best practices of our human heritage we can make a difference. It is the responsibility of all stakeholders of education to support and contribute to this shift
Molecular dynamics simulation on the effect of transition metal binding to the N-terminal fragment of amyloid-Ī²
Get PDFWe report molecular dynamics simulations of three possible adducts of Fe(II) to the N-terminal 1ā16 fragments of the amyloid-Ī² peptide, along with analogous simulations of Cu(II) and Zn(II) adducts. We find that multiple simulations from different starting points reach pseudo-equilibration within 100ā300āns, leading to over 900āns of equilibrated trajectory data for each system. The specifics of the coordination modes for Fe(II) have only a weak effect on peptide secondary and tertiary structures, and we therefore compare one of these with analogous models of Cu(II) and Zn(II) complexes. All share broadly similar structural features, with mixture of coil, turn and bend in the N-terminal region and helical structure for residues 11ā16. Within this overall pattern, subtle effects due to changes in metal are evident: Fe(II) complexes are more compact and are more likely to occupy bridge and ribbon regions of Ramachandran maps, while Cu(II) coordination leads to greater occupancy of the poly-proline region. Analysis of representative clusters in terms of molecular mechanics energy and atoms-in-molecules properties indicates similarity of four-coordinate Cu and Zn complexes, compared to five-coordinate Fe complex that exhibits lower stability and weaker metalāligand bonding
Differences in both prevalence and titre of specific immunoglobulin E among children with asthma in affluent and poor communities within a large town in Ghana.
Get PDFBackground Reports from several African countries have noted an increasing prevalence of asthma in areas of extensive urbanization. Objective To investigate the relevance of allergen-specific sensitization and body mass index (BMI) to asthma/wheezing and exercise-induced bronchospasm (EIB) among children from affluent and poorer communities within a large town in Ghana. Methods Children with physician-diagnosed asthma and/or current wheezing aged 9-16 years (n=99; cases) from three schools with differing socio-economic backgrounds [urban affluent (UA), urban poor (UP) or suburban/rural (SR)] were recruited from a cross-sectional study (n=1848) in Kumasi, Ghana, and matched according to age, sex and area of residence with non-asthmatic/non-wheezy controls. We assayed sera for IgE antibodies to mite, cat, dog, cockroach, Ascaris and galactose-Ī±-1,3-galactose. Results Children from the UA school had the lowest total serum IgE. However, cases from the UA school had a higher prevalence and mean titre of sIgE to mite (71.4%, 21.2IU/mL) when compared with controls (14.3%, 0.8IU/mL) or cases from UP (30%, 0.8IU/mL) and SR community (47.8%, 1.6IU/mL). While similar findings were observed with EIB in the whole population, among cases there was no difference in IgE antibody prevalence or titre between children with or without EIB. BMI was higher among UA children with and without asthma; in UP and SR communities, children with EIB (n=14) had a significantly higher BMI compared with children with asthma/wheezing without EIB (n=38) (18.2 vs. 16.4, respectively, P<0.01). Conclusions and Clinical Relevance In the relatively affluent school, asthma/wheezing and EIB were associated with high titre IgE antibodies to mite, decreased total IgE, and increased BMI. This contrasted with children in the urban poor school and suggests that changes relevant to a Western model of childhood asthma can occur within a short geographical distance within a large city in Africa. Ā© 2011 Blackwell Publishing Ltd
Solution phase, solid state, and theoretical investigations on the MacMillan imidazolidinone
Get PDFA combination of soln. phase NMR, X-ray crystallog. studies, and DFT calcns. provide a consistent structural conformation for iminium ions derived from the MacMillan imidazolidinone
Ligand field molecular dynamics simulation of Pt(II)-phenanthroline binding to N-terminal fragment of amyloid-Ī² peptide
Get PDFWe report microsecond timescale molecular dynamics simulation of the complex formed between Pt(II)-phenanthroline and the 16 N-terminal residues of the AĪ² peptide that is implicated in the onset of Alzheimerās disease, along with equivalent simulations of the metal-free peptide. Simulations from a variety of starting points reach equilibrium within 100 ns, as judged by root mean square deviation and radius of gyration. Platinum-bound peptides deviate rather more from starting points, and adopt structures with larger radius of gyration, than their metal-free counterparts. Residues bound directly to Pt show smaller fluctuation, but others actually move more in the Pt-bound peptide. Hydrogen bonding within the peptide is disrupted by binding of Pt, whereas the presence of salt-bridges are enhanced
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Structural variability of 4f and 5f thiocyanate complexes and dissociation of uranium(III)āthiocyanate bonds with increased ionicity
Get PDFA series of complexes [Et4N][Ln(NCS)4(H2O)4] (Ln = Pr, Tb, Dy, Ho, Yb) have been structurally characterized, all showing the same structure, namely a distorted square antiprismatic coordination geometry, and the LnāO and LnāN bond lengths following the expected lanthanide contraction. When the counterion is Cs+, a different structural motif is observed and the eight-coordinate complex Cs5[Nd(NCS)8] isolated. The thorium compounds [Me4N]4[Th(NCS)7(NO3)] and [Me4N]4[Th(NCS)6(NO3)2] have been characterized, and high coordination numbers are also observed. Finally, attempts to synthesize a U(III) thiocyanate compound has been unsuccessful; from the reaction mixture, a heterocycle formed by condensation of five MeCN solvent molecules, possibly promoted by U(III), was isolated and structurally characterized. To rationalize the inability to isolate U(III) thiocyanate compounds, thin-layer cyclic voltammetry and IR spectroelectrochemistry have been utilized to explore the cathodic behavior of [Et4N]4[U(NCS)8] and [Et4N][U(NCS)5(bipy)2] along with a related uranyl compound [Et4N]3[UO2(NCS)5]. In all examples, the reduction triggers a rapid dissociation of [NCS]ā ions and decomposition. Interestingly, the oxidation chemistry of [Et4N]3[UO2(NCS)5] in the presence of bipy gives the U(IV) compound [Et4N]4[U(NCS)8], an unusual example of a ligand-based oxidation triggering a metal-based reduction. The experimental results have been augmented by a computational investigation, concluding that the U(III)āNCS bond is more ionic than the U(IV)āNCS bond
Metal binding to amyloid-Ī²1ā42: a ligand field molecular dynamics study
Get PDFLigand field molecular mechanics simulation has been used to model the interactions of copper(II) and platinum(II) with the amyloid-Ī²1ā42 peptide monomer. Molecular dynamics over several microseconds for both metalated systems are compared to analogous results for the free peptide. Significant differences in structural parameters are observed, both between Cu and Pt bound systems as well as between free and metal-bound peptide. Both metals stabilize the formation of helices in the peptide as well as reducing the content of Ī² secondary structural elements compared to the unbound monomer. This is in agreement with experimental reports of metals reducing Ī²-sheet structures, leading to formation of amorphous aggregates over amyloid fibrils. The shape and size of the peptide structures also undergo noteworthy change, with the free peptide exhibiting globular-like structure, platinum(II) system adopting extended structures, and copper(II) system resulting in a mixture of conformations similar to both of these. Salt bridge networks exhibit major differences: the Asp23-Lys28 salt bridge, known to be important in fibril formation, has a differing distance profile within all three systems studied. Salt bridges in the metal binding region of the peptide are strongly altered; in particular, the Arg5-Asp7 salt bridge, which has an occurrence of 71% in the free peptide, is reduced to zero in the presence of both metals
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