Cascade-Exciton Model Analysis of Proton Spallation from 10 MeV to 5 GeV

We have used an extended version of the Cascade-Exciton Model (CEM) to analyze more than 600 excitation functions for proton induced reactions on 19 targets ranging from C-12 to Au-197, for incident energies ranging from 10 MeV to 5 GeV. We have compared the calculations to available data, to calculations using approximately two dozen other models, and to predictions of several phenomenological systematics. We present here our conclusions concerning the relative roles of different reaction mechanisms in the production of specific final nuclides. We comment on the strengths and weaknesses of the CEM and suggest possible further improvements to the CEM and to other models.Comment: 9 pages, to be published in Nuclear Instruments and Methods

Evaluation of the cytotoxic and genotoxic potential of Khat (Catha edulis Forsk) extracts on human T lymphoblastoid cell line

This paper reports on an investigation of the cytotoxic and genotoxic potential of khat extract using a human T lymphoblastoid cell line (CEM). Exponentially growing CEM cells were cultured for 12 h in the presence of khat extract (0-2000 μg ml-1). Statistically significant, dose-dependent increases in; CEM cell death at dose (> 400 μg ml-1), in DNA damage at dose (>200 μg ml-1) and in micronuclei frequency, at dose (>200 μg ml-1) were observed. The genetic damage effects of khat extract on human cell line observed in this study could serve as a major contribution towards the understanding and creating of awareness of an increased risk of cancer amongst long-term khat consumers

Residual capability of alkali binding by hydrated pozzolanic cements in long-service concrete structures

An experimental procedure was developed and applied to cement pastes made with two different pozzolanic cements (CEM IV/B (P) and CEM IV/B (V)) in order to ascertain the existence of a residual capability of alkali binding by long-term hydrated pozzolanic cements and, at the same time, to evaluate the alkali retention capability and the concentration of OH- ions in the pore solution of such cementitious matrices. The developed procedure consisted of accelerated curing of cement paste specimens (150 days at 60°C and 100% RH), subsequent leaching tests at 60°C for 30 days by using deionized water or basic solutions (NaOH or KOH at different concentrations) as leaching media, and correlation of the leaching test results with a simple mass balance equation for sodium and potassium ions. The developed procedure was found to be appropriate for evaluating both the pore liquid alkalinity and the alkali retention capability by long-term hydrated pozzolanic cement pastes. A residual capability of alkali binding was also identified for both tested pozzolanic cements, thus indicating their potential ability to prevent (CEM IV/B (V)) or minimize (CEM IV/B (P)) the risk of deleterious expansion associated to alkali-aggregate reaction in long-service concrete structures, like concrete dams

Systemic evaluation of a community environmental management programme

Community environmental management (CEM) involves achieving environmental objectives through the facilitation of community partnerships, local dialogues, consultations and participative decision making. This is increasingly seen as a solution to some of the more complex environmental issues facing regulatory authorities. However, little has been written about how CEM programmes should be evaluated, and this is particularly concerning given that the establishment of a causal relationship between community participation and environmental outcomes is not straight forward. Anecdotal evidence suggests that CEM programmes have much potential, but the lack of a robust evidence-base for their effectiveness means that their role in resource management is often not well understood or well integrated with other environmental management tools and processes. This paper reports on a project that developed a novel, systemic CEM evaluation methodology and trialled it in an intervention with a regional council in New Zealand. The methodology has the potential to be adapted for other contexts where there is a need for more robust evidence of the value (or otherwise) of CEM

Cascade-Exciton Model Analysis of Nucleon-Induced Fission Cross Sections of Lead and Bismuth at Energies from 45 to 500 MeV

An extended version of the Cascade-Exciton Model (CEM) of nuclear reactions is applied to analyze nucleon-induced fission cross sections for Bi-209 and Pb-208 nuclei in the 45-500 MeV energy range. The available data on linear momentum transfer are analyzed as well. The results are compared with analytical approximations resulting from a comparative critical analysis of all available experimental data. Systematic discrepancies between calculations and experimental data are revealed. A modification of the CEM is proposed, which significantly improves the model predictions for projectile energies above 100 MeV.Comment: 38 pages, 16 figures, 7 tables, LaTeX, submitted to Nucl. Sci. En

Topological phase in a non-Hermitian PT symmetric system

In this work, we consider a tight binding lattice with two non-Hermitian impurities. The system is described by a non-Hermitian generalization of the Aubry Andre model. We show for the first time that there exists topologically nontrivial edge states with real spectra in the PT symmetric region.Comment: To Appear in PL

Amine functionalization of cholecyst-derived extracellular matrix with generation 1 PAMAM dendrimer

This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Biomacromolecules, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/doi/pdf/10.1021/bm701055k.A method to functionalize cholecyst-derived extracellular matrix (CEM) with free amine groups was established in an attempt to improve its potential for tethering of bioactive molecules. CEM was incorporated with Generation-1 polyamidoamine (G1 PAMAM) dendrimer by using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide and N-hydroxysuccinimide cross-linking system. The nature of incorporation of PAMAM dendrimer was evaluated using shrink temperature measurements, Fourier transform infrared (FTIR) assessment, ninhydrin assay, and swellability. The effects of PAMAM incorporation on mechanical and degradation properties of CEM were evaluated using a uniaxial mechanical test and collagenase degradation assay, respectively. Ninhydrin assay and FTIR assessment confirmed the presence of increasing free amine groups with increasing quantity of PAMAM in dendrimer-incorporated CEM (DENCEM) scaffolds. The amount of dendrimer used was found to be critical in controlling scaffold degradation, shrink temperature, and free amine content. Cell culture studies showed that fibroblasts seeded on DENCEM maintained their metabolic activity and ability to proliferate in vitro. In addition, fluorescence cell staining and scanning electron microscopy analysis of cell-seeded DENCEM showed preservation of normal fibroblast morphology and phenotype

Customer Enquiry Management in a Global Competitive Context: A Comparative Multi-Case Study Analysis

Business-to-Business (B2B) relationships, such as between a manufacturer and a customer, are increasingly important during the Customer Enquiry Management (CEM) process, particularly so for non-Make-To-Stock (non-MTS) companies operating in industrial markets. Few empirical studies have explored the CEM practices adopted by firms in practice. A study of the Italian capital goods sector by Zorzini et al. (2007) is a recent exception. Moreover, most studies have approached CEM from a cross-department integrated perspective but in the digital economy, and with globalization, outsourcing and extended supply chains, CEM needs to be approached from a broader supply chain-oriented perspective, incorporating B2B exchanges. This paper builds on the study by Zorzini et al. (2007) by conducting multi-case study research with seven UK-based companies in the capital goods sector, including three sales and support companies with offshore manufacturing. By adopting a cross-national research perspective, it assesses whether the proposed theory applies to other capital goods firms outside Italy. By also adopting a supply chain perspective of CEM it investigates current industry practice in B2B markets and explores whether cross-functional coordination and formalization issues can be extended into a global context. Evidence from the UK generally supports prior theory, confirming links between high levels of coordination, formalization of the CEM process and improved performance. Some refinements are proposed, for example, in order to make the theory suitable for a global context. The characteristics of a supply chain are important factors that affect CEM. This research has managerial implications for improving the CEM process in non-Make-To-Stock (non-MTS) capital goods companies from both an intra and an inter-organisational (B2B) perspective. Coordination with partners along the supply chain is needed at the enquiry stage and constraints linked to global customers should be considered when structuring the

One pot domino synthesis of polyvicinalamine monomers

On a genere de l'imidazole par une reaction de type domino in situ entre le glyoxal, le formaldehyde et deux unites d'ammoniac aqueux. L'addition de bicarbonate aqueux et d'un anhydride carboxylique ou d'un dicarbonate de dialkyle conduit a la formation de la N,N'-diacyl- ou N,N'-dicarbalkoxy-2-hydroxyimidazoline correspondante. Il s'ensuit une reaction de clivage de cycle de Bamberger qui permet d'isoler facilement le cis-1,2-di(acetamido)ethene, le cis-1,2-di(propylamido)ethene, le cis-1,2-di(ethoxyamido)ethene, le cis-1,2-di(tert-butoxyamido)ethene ou le cis-1,2-di(benzamido)ethene sous la forme de solides. La facilite et la generalite offerte par cette approche monotope implique une voie efficace du point de vue des couts en vue de la synthese de routine de precurseurs d'amines oligo- et polyvicinales