Femtosecond lasers for mass spectrometry: Proposed application to catalytic hydrogenation of butadiene

Mass spectra from the interaction of intense, femtosecond laser pulses with 1,3-butadiene, 1-butene, and n-butane have been obtained. The proportion of the fragment ions produced as a function of intensity, pulse length, and wavelength was investigated. Potential mass spectrometry applications, for example in the analysis of catalytic reaction products, are discussed.

Challenges of UK/Irish Contractors Regarding Material Management and Logistics in Confined Site Construction

The aim of this paper is to identify the various managerial issues encountered by UK/Irish contractors in the management of materials in confined urban construction sites. Through extensive literature review, detailed interviews, case studies, cognitive mapping, causal loop diagrams, questionnaire survey and documenting severity indices, a comprehensive insight into the materials management concerns within a confined construction site environment is envisaged and portrayed. The leading issues highlighted are: that contractors’ material spatial requirements exceed available space, it is difficult to coordinate the storage of materials in line with the programme, location of the site entrance makes delivery of materials particularly difficult, it is difficult to store materials on-site due to the lack of space, and difficult to coordinate the storage requirements of the various sub-contractors. With the continued development of confined urban centres and the increasing high cost of materials, any marginal savings made on-site would translate into significant monetary savings at project completion. Such savings would give developers a distinct competitive advantage in this challenging economic climate. As on-site management professionals successfully identify, acknowledge and counteract the numerous issues illustrated, the successful management of materials on a confined urban construction site becomes attainable.

Confined site construction: An empirical analysis of factors impacting health and safety management

Purpose – The purpose of this paper is to identify, clarify and tabulate the various managerial issues encountered, to aid in the management of the complex health and safety concerns which occur within a confined construction site environment.

Design/methodology/approach – This is achieved through conducting extensive qualitative and qualitative research in the form of case studies, interviews and questionnaire survey.

Findings – The leading managerial issues in the management of health and safety on a confined construction site are found to be: “Difficulty to move materials around site safely”; “Lack of adequate room for the effective handling of materials”; “Difficulty in ensuring site is tidy and all plant and materials are stored safely”; “Close proximity of individuals to operation of large plant and machinery”; and joint fifth “Difficulty in ensuring proper arrangement and collection of waste materials on-site” along with “Difficulty in controlling hazardous materials and equipment on site”.

Practical implications – The resulting implication for practice of these results can be summarised by identifying that with sustained development of urban centres on a global scale, coupled with the increasing complexity of architectural designs, the majority of on-site project management professionals are faced with the onerous task of completing often intricate designs within a limited spatial environment, under strict health and safety parameters.

Originality/value – The subsequent value of the findings are such that just as on-site management professionals successfully identify the various managerial issues highlighted, the successful management of health and safety on a confined construction site is attainable.

Critical factors affecting management of site operatives and personal in confined construction site

The aim of this paper is to identify and classify the numerous managerial issues encountered in the management of personnel in confined site construction. For the purpose of this research, a confined construction site is defined as a site where permanent works fit the site footprint, extending to levels above and/or below ground level, leaving spatial restrictions for other operations (e.g. plant and material movements, materials storage and temporary accommodation etc.) and require effective resource co-ordination beyond normal on-site management input. A literature review and analysis, case studies incorporating interviews and focus groups along with a questionnaire survey were used in order to gain a comprehensive insight into the issues in the management of personnel in a confined construction site environment. The following are the top five leading issues highlighted in the management of personnel in confined site construction; (1) Accidents due to an untidy site, (2) One contractor holding up another because of the lack of space, (3) A risk to personnel because of vehicular traffic on-site, (4) Difficult to facilitate several contractors at one work location, and (5) Numerous personnel working within the one space. In today’s modern environment, spatial restrictions are quickly becoming the norm in the industry. Therefore, the management of personnel on-site becomes progressively more difficult with the decrease in available space on-site. Where such environments exist, acknowledging the numerous issues highlighted above, aids site management in the supervision and co-ordination of personnel on-site, thus reducing accidents, increasing productivity and increase profit margins, in spatially restricted environments. As on-site management professionals successfully identify, acknowledge and counteract the numerous issues illustrated, the successful management of personnel on a confined construction site is achievable. By identifying the numerous issues, on-site management can proactively mitigate such issues through adopting counteractive measures and through successful identification of the traits identified.

Effects of Charge Location on the Absorptions and Lifetimes of Protonated Tyrosine Peptides in Vacuo

Nearby charges affect the electronic energy levels of chromophores, with the extent of the effect being determined by the magnitude of the charge and degree of charge-chromophore separation. The molecular configuration dictates the charge chromophore distance. Hence, in this study, we aim to assess how the location of the charge influences the absorption of a set of model protonated and diprotonated peptide ions, and whether spectral differences are large enough to be identified. The studied ions were the dipeptide YK, the tripeptide KYK (Y = tyrosine; K = lysine) and their complexes with 18-crown-6-ether (CE). The CE targets the ammonium group by forming internal ionic hydrogen bonds and limits the folding of the peptide. In the tripeptide, the distance between the chromophore and the backbone ammonium is enlarged relative to that in the dipeptide. Experiments were performed in an electrostatic ion storage ring using a tunable laser system, and action spectra based on lifetime measurements were obtained in the range from 210 to 310 nm. The spectra are all quite similar though there seems to be some changes in the absorption band between 210 and 250 nm, while in the lower energy band all ions had a maximum absorption at similar to 275 nm. Lifetimes after photoexcitation were found to shorten upon protonation and lengthen upon CE complexation, in accordance with the increased number of degrees of freedom and an increase in activation energies for dissociation as the mobile proton model is no longer operative.

Measurement of absolute charge-exchange cross sections for He2+ collisions with He and H-2

Reported are total, absolute charge-exchange cross sections for collisions of 3He(2+) ions with He and H-2. Measurements are reported at fixed energies between 0.33 and 4.67 keV/amu. Both the present results and earlier results of others are analyzed in terms of available experimental small-angle differential cross sections as a function of collision energy, and hence the geometry of the exit aperture of the gas-collision cells used by the various experimental groups. In addition, the effective length of gas-collision cells is studied using fluid dynamic and molecular flow simulations to address the density patterns near the cell entrance and exit apertures. When small acceptance-angle corrections were applied, the results of present and previous measurements for the single electron capture in these systems were brought into good accord in the relevant energy ranges. Taken in their entirety, the present data for 3He(2+) with He and H-2 lend themselves to new theoretical calculations of the multichannel charge-exchange cross sections.

A Framework for Stakeholder Management and Corporate Culture

Purpose: This paper investigates the link between two knowledge areas that have not been previously linked conceptually; stakeholder management and corporate culture. Focussing on the UK Construction Industry, the research study demonstrates mutual dependency of each of these areas on the other and establishes a theoretical framework with real potential to impact positively upon industry.

Design/methodology/approach: The study utilises both qualitative and quantitative data collection and then analysis to produce results contributing to the final framework. Semi-structured interviews were used and analysed through a cognitive mapping procedure. The result of this stage, set in the context of previous research, facilitated a questionnaire to be developed which helped gather quantitative values from a larger sample to enhance the final framework.

Findings: The data suggests that stakeholder management and corporate culture are key areas of an organisation’s success, and that this importance will only grow in future. A clearly identifiable relationship was established between the two theoretical areas and a framework developed and quantified.

Originality/value: It is evident that change is needed within the UK Construction Industry. Companies must employ ethical and social stakeholder management and manage their corporate culture like any other aspect of their business. Successfully doing this will lead to more successful projects, better reputation and survival. The findings of this project begin to show how change may occur and how companies might intentionally deploy advantageous configurations of corporate culture and stakeholder management.

Population-based study reveals new risk-stratification biomarker panel for Barrett's esophagus

BACKGROUND & AIMS: The risk of progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) is low and difficult to calculate. Accurate tools to determine risk are needed to optimize surveillance and intervention. We assessed the ability of candidate biomarkers to predict which cases of BE will progress to EAC or high-grade dysplasia and identified those that can be measured in formalin-fixed tissues. METHODS: We analyzed data from a nested case-control study performed using the population-based Northern Ireland BE Register (1993-2005). Cases who progressed to EAC (n = 89) or high-grade dysplasia =6 months after diagnosis with BE were matched to controls (nonprogressors, n = 291), for age, sex, and year of BE diagnosis. Established biomarkers (abnormal DNA content, p53, and cyclin A expression) and new biomarkers (levels of sialyl Lewis(a), Lewis(x), and Aspergillus oryzae lectin [AOL] and binding of wheat germ agglutinin) were assessed in paraffin-embedded tissue samples from patients with a first diagnosis of BE. Conditional logistic regression analysis was applied to assess odds of progression for patients with dysplastic and nondysplastic BE, based on biomarker status. RESULTS: Low-grade dysplasia and all biomarkers tested, other than Lewis(x), were associated with risk of EAC or high-grade dysplasia. In backward selection, a panel comprising low-grade dysplasia, abnormal DNA ploidy, and AOL most accurately identified progressors and nonprogressors. The adjusted odds ratio for progression of patients with BE with low-grade dysplasia was 3.74 (95% confidence interval, 2.43-5.79) for each additional biomarker and the risk increased by 2.99 for each additional factor (95% confidence interval, 1.72-5.20) in patients without dysplasia. CONCLUSIONS: Low-grade dysplasia, abnormal DNA ploidy, and AOL can be used to identify patients with BE most likely to develop EAC or high-grade dysplasia.

Functional characterization and membrane topology of Escherichia coli WecA, a sugar-phosphate transferase initiating the biosynthesis of enterobacterial common antigen and O-antigen lipopolysaccharide

WecA is an integral membrane protein that initiates the biosynthesis of enterobacterial common antigen and O-antigen lipopolysaccharide (LPS) by catalyzing the transfer of N-acetylglucosamine (GlcNAc)-1-phosphate onto undecaprenyl phosphate (Und-P) to form Und-P-P-GlcNAc. WecA belongs to a large family of eukaryotic and prokaryotic prenyl sugar transferases. Conserved aspartic acids in putative cytoplasmic loops 2 (Asp90 and Asp91) and 3 (Asp156 and Asp159) were targeted for replacement mutagenesis with either glutamic acid or asparagine. We examined the ability of each mutant protein to complement O-antigen LPS synthesis in a wecA-deficient strain and also determined the steady-state kinetic parameters of the mutant proteins in an in vitro transfer assay. Apparent K(m) and V(max) values for UDP-GlcNAc, Mg(2+), and Mn(2+) suggest that Asp156 is required for catalysis, while Asp91 appears to interact preferentially with Mg(2+), possibly playing a role in orienting the substrates. Topological analysis using the substituted cysteine accessibility method demonstrated the cytosolic location of Asp90, Asp91, and Asp156 and provided a more refined overall topological map of WecA. Also, we show that cells expressing a WecA derivative C terminally fused with the green fluorescent protein exhibited a punctate distribution of fluorescence on the bacterial surface, suggesting that WecA localizes to discrete regions in the bacterial plasma membrane.