Aptamer-based cocaine assay using a nanohybrid composed of ZnS/Ag2Se quantum dots, graphene oxide and gold nanoparticles as a fluorescent probe

Authors report on a new fluoro-graphene-plasmonic nanohybrid aptamer-based fluorescent nanoprobe for cocaine. To construct the nanoprobe, newly synthesized glutathione-capped ZnS/Ag 2Se quantum dots (QDs) were first conjugated to graphene oxide (GO) to form a QD-GO nanocomposite. The binding interaction resulted in a fluorescence turn-ON. Thereafter, cetyltrimethylammonium bromide (CTAB)-gold nanoparticles (AuNPs) were directly adsorbed on the QD-GO nanocomposite to form a novel QD-GO-CTAB-AuNP nanohybrid assembly that resulted in a fluorescence turn-OFF. Streptavidin (strep) was then adsorbed on the QDs-GO-CTAB-AuNP nanohybrid assembly which allowed binding to a biotinylated MNS 4.1 anticocaine DNA aptamer (B) receptor. The addition of cocaine into the strep-B-QDs-GO-CTAB-AuNP aptamer nanoprobe system aided affinity to the aptamer receptor and in turn turned on the fluorescence of the nanoprobe in a concentration-dependent manner. Under optimum experimental conditions, we found the strep-B-QD-GO-CTAB-AuNP to be far superior in its sensitivity to cocaine than the tested strep-B-QDs (no GO and CTAB-AuNPs), strep-B-QD-CTAB-AuNP (no GO) and strep-B-QD-GO (no CTAB-AuNP). In addition, the investigation of localized surface plasmon resonance (LSPR) amplified signal from tested plasmonic NPs shows that CTAB-AuNPs was far superior in amplifying the fluorescence signal of the nanoprobe. A detection limit of 4.6 nM (1.56 ng.mL −1), rapid response time (~2 min) and excellent selectivity against other drugs, substances and cocaine metabolites was achieved. The strep-B-QD-GO-CTAB-AuNP aptamer-based fluorescent nanoprobe was successfully applied for the determination of cocaine in seized adulterated cocaine samples.</p

A Study of Valuation Clients Perception on Mortgage Valuation Reliability

The effect of overvaluation and undervaluation cannot be over emphasized in any economy. Valuation opinions are very crucial to the operations and business dealings of the clients that seek valuer’s advice in decision making. Wrong opinion of value has caused strain in many business dealings. This paper studies the perception of clients on reliability of mortgage valuation in Nigeria. A sample size of 50 lending institutions was randomly chosen representing 57.5% of the target population in Lagos State, the study area. The study used descriptive statistic to analyse the data. The study reveals that clients are of the opinion that valuations produced by valuers were not reliable. This is as a result of the experiences they were having with large disparity between the final opinion of values of those properties on default mortgage that were foreclosed and the final sales price. The study therefore concludes that the estate surveyors and valuers in the country owe their clients a duty of care by presenting accurate and reliable valuation reports since other stakeholders of the real property investors depend on these reports for their investment decision

Slum Settlements Regeneration in Lagos Mega-city: an Overview of a Waterfront Makoko Community

Urban degradation is caused principally by urbanization process, however, most of the environmental problems in Lagos suburbs result largely from its unplanned landuses, swampy nature of built areas and weak development control. Other critical problems that bother minds also include lack of open space, poor management of flood channels and substandard housing. This paper discuses the possible intervention strategies in the regeneration effort of Makoko - a submerged residential enclave located in Yaba local government area of Lagos. The research method which is both narrative and statistically descriptive in nature enables the author engage in a detailed literature study of the chronological development of Lagos with view to determining how the mega city came about the current level of degenerating infrastructural facilities. The study found that the principle of cooperative leadership by government at all levels is fundamental to making important difference in qualitative development controls of the study area. It however concluded that the duo role of the public and traditional power structure of the community leaders must be involved in the conception and implementation of Makoko’s environmental planning programmes

Navigating Metaphorical Expressions through Design Problem Solving: A Perspective of Design Critic in a Creative Economy

In the school of creativity, Metaphors are tools and weapons that designers employs during intellectual navigation to understand unfamiliar design problems and are as useful as criticism to an art-teacher in portfolio grading, assessment and examination. A connecting thread is found by juxtaposing metaphor and criticism in which a creative end is reached for both the Art-teachers and students in academe and practice. Thus in a developing economy where design endeavor gains nobility, a creative product emerges and retrieving concepts from metaphors necessitates creative thinking. While the importance of these creative tools has been acknowledged in design, more research work is needed to appreciate its contribution to design practice. This investigation is aimed at building a connecting thread resilient enough to create a synergy between the uses of metaphor in design criticism and meaningful design problem solving with a particular focus on design creativity. Overt meaning of metaphorical expressions, factors of creativity and constructive criticism were interpolated into a holistic value. Critical evaluation showed that the connection of metaphor and criticism is the most significant factor characterizing design evolution and creativity. On the other hand, the synthesis of design solutions is the stronger factor of the use of metaphors. Evaluation in this paper demonstrates that correct use of metaphorical expressions play an important role in design creativity. Theoretical discourse analysis of metaphorical expressions in design problems was the screen that showed unique contributions of criticism to individual potential discoveries and general creativity by design problem solving in a dynamic econom

The Need for Residential Tenancy Databases in Nigeria

Bad tenants can be a real problem for not paying rent on time or leaving properties in a mess. Lodged information about bad tenants in tenancy databases assists estate agents and landlords make more informed decisions. The study examines the need for residential tenancy databases in Nigeria. Often times, details on a tenancy application form may not be enough to make an informed decision about whether or not the applicant will be a good tenant. The study employed study focus groups using semi-structured face-to-face interviews to gather data among ten principals of estate surveying and valuation firms in Ikeja, Lagos on the one hand; ten prominent local estate agents; five prominent practicing lawyers, ten landlords of multi-tenanted properties and forty tenants within Baruwa/Ipaja neighbourhood in Alimosho Local Government Council area of Lagos State, on the other hand through purposive sampling method. The survey was carried out between September and December, 2013. Data were analysed using tables, percentages and ranking. The study showed that landlords, estate agents and lawyers ranked ability to guide and guard against loss of income to all participants in the real estate business as first and paramount reason for the call for tenancy database. The need to minimize capital loss to landlords was ranked second with ensuring a reduction in overhead expenses by landlords as third. However, public feelings about landlord’s rights on control of building use and character or emotions have no strong weight since for any business venture to be sustainable, a balance of power to a certain level, must exist between the investor and the product consumers

COMPARATIVE EVALUATION OF VARIETIES OF COWPEA AND ITS EFFECT ON FERTILTY STATUS OF LATERITIC SOIL OF LANDMARK UNIVERSITY

Identification of cowpea varieties with superior grain yield and high soil fertility enhancing potential is crucial to increasing productivity of the crop among small-scale farmers in Omu-Aran, Kwara State. A field experiment was carried out during the 2014 growing season to evaluate two cowpea varieties for their grain yield and their effect on fertility status of Lateritic soils of Landmark University Teaching and Research Farm. The varieties evaluated were IAR 48 and IAR 2.5.6. Variety IAR 2.5.6 produced the highest grain yield compared to variety IAR 2.5.6. The study also revealed the potential of cowpea in improving the fertility status of Lateritic soils as there was significant difference observed in some of the chemical properties analyzed including available Phosphorus, Exchangeable Calcium, Magnesium, Potassium and Sodium