Lightweight Concrete Using Local Industrial By-product

Construction is one of the largest users of energy, material resources and water and it is a formidable polluter. One of the major materials used in construction is concrete and ordinary concrete contains about 12% cement which is a major producer of greenhouse gas in the world. The use of waste materials as partial replacement of cement in concrete reduces greenhouse gases, frees up land fill space, and reduces raw materials consumption. This contributes towards sustainable development, as in a sustainable society, nature is not subject to systematically increasing concentrations of substances extracted from the earth＇s crust. This research work explores the possibility of replacing some percentage of cement in concrete with marble sludge powder to produce lightweight concrete. This was achieved by determining the compressive strength and some hardened properties of concrete like sorptivity and carbonation with marble sludge. The results so far have been able to prove that lightweight concrete can be produced when some percentage of cement is replaced with this waste.     

In Silico Structural Modeling and Analysis of Interactions of Tremellomycetes Cytochrome P450 Monooxygenases CYP51s with Substrates and Azoles

Cytochrome P450 monooxygenase CYP51 (sterol 14α-demethylase) is a well-known target of the azole drug fluconazole for treating cryptococcosis, a life-threatening fungal infection in immune-compromised patients in poor countries. Studies indicate that mutations in CYP51 confer fluconazole resistance on cryptococcal species. Despite the importance of CYP51 in these species, few studies on the structural analysis of CYP51 and its interactions with different azole drugs have been reported. We therefore performed in silico structural analysis of 11 CYP51s from cryptococcal species and other Tremellomycetes. Interactions of 11 CYP51s with nine ligands (three substrates and six azoles) performed by Rosetta docking using 10,000 combinations for each of the CYP51-ligand complex (11 CYP51s × 9 ligands = 99 complexes) and hierarchical agglomerative clustering were used for selecting the complexes. A web application for visualization of CYP51s’ interactions with ligands was developed (http://bioshell.pl/azoledocking/). The study results indicated that Tremellomycetes CYP51s have a high preference for itraconazole, corroborating the in vitro effectiveness of itraconazole compared to fluconazole. Amino acids interacting with different ligands were found to be conserved across CYP51s, indicating that the procedure employed in this study is accurate and can be automated for studying P450-ligand interactions to cater for the growing number of P450s.     

Improvement of Gas Chromatographic Performance of Cyclic Siloxane Bonded Phases by Incorporation of n-Alkyl Groups

Cyclic siloxane-based silica columns of high retention capacity for light hydrocarbons were prepared by incorporation of octyl and octadecyl groups on the siloxane skeleton. Spectroscopic studies revealed the presence of the alkyl groups on the silica surface, which results in high surface coverage of the packing materials. The retention characteristics of the columns are significantly higher than those of cyclic siloxane phases due to their high surface coverage and better solute-stationary phase interactions. In agreement with previous data for micropacked columns, the H vs ū curves, on passing through the optimum region, remained substantially constant at high linear gas velocities, indicating their usefulness for fast analysis of light hydrocarbons at high flow rates without any appreciable loss in column performance. Presumably due to greater availability of the bonded alkyl groups for interactions, a 10-component mixture of C(1)-C(4) saturated and unsaturated hydrocarbons was sufficiently separated on the hexamethylcyclotrisiloxane-octadecylsilyl phase compared to the conventional octadecyldimethylsilyl phase, irrespective of the high carbon content of the latter.     

Understanding the Underrepresentation of Qualitative Research Approaches to Built Environment Research in Nigeria

There is evidence that scholars in some countries, including Nigeria, primarily employ the quantitative approach to research, and that in some cases this approach is used inappropriately. This leaves research questions that should be tackled from a qualitative standpoint either unaddressed or incorrectly addressed. The aim of this study is to understand why the qualitative approach (QA) has failed to gain similar recognition in Nigeria and other countries, and by extension, the disposition of researchers towards its use. The impact of the disposition of researchers toward QA was also explored. Researchers in the various built environment (BE) disciplines in Nigeria were interviewed. The results revealed that there is a preference for quantitative research, while QAs are used if convenient. Furthermore, the study revealed that the educational background of academics and their poor understanding of the qualitative paradigm explain their disposition toward the adoption of the QA in research. This finding suggests that academic followers instead of leaders are being produced, and that research is done for ad hominem promotion. In advancing the understanding of QA in BE research in Nigeria, this study also draws the attention of stakeholders in the academia to the implications of a preference by researchers for quantitative research.     

Active Robust Resource Management in Cluster Computing Using Policies

We present an implementation of a policy-based management architecture for emerging communications and computing paradigms such as Active Networks and the Grid. To manage such open, highly distributed and decentralized environments, an approach based on policy concepts is adopted, allowing support for active, dynamic adaptability in network elements, services and end-user applications, as well as achieving decentralization and distribution. We present our flexible, extensible policy and event specifications in XML, and describe our management architecture. One key feature of our approach is the distributed infrastructure: the Directory and the Management Information Distribution system. The second feature is the Resource and Security Management elements residing on the multi-node managed systems. These combine to provide a light-weight, self-organizing management architecture. As an applications example, we describe the implementation of our management system applied to the Application Level Active Networking (ALAN) environment, implemented in the European Commission Information Society Technologies (IST) project ANDROID.