Factors Affecting the Competencies and Project Delivery of Small-Sized Indigenous Construction Firms in Lagos State

Every industry is prone to problems Performance is a general challenge affecting construction and most especially small-sized indigenous construction companies. The study focused on determining the likely factors affecting the competencies and project delivery of small-sized construction firms in Lagos. 60 questionnaires were designed and administered to professionals (15-Architects, 15-Builders, 15-Engineers, and 15-Quantity Surveyors) working in the construction companies in Lagos State and 48 questionnaires were retrieved. These questionnaires were analysed with SPSS and several findings were derived from this analysis. The various factors affecting the performance and project delivery at varying degrees are: high cost of plants, equipment, materials and labour, lack of skilled craftsmen, unavailability of funds, poor managerial skills, lack of government patronage, and poor communication among stakeholders. The study found out that the most prominent factors are poor managerial skills, lack of project planning and unavailability of funds. The main factors affecting the performance of small sized indigenous construction firms are based on three key elements namely time, quality and cost. These three elements when properly harnessed will increase the performance of small sized indigenous firms. The study recommended that the use of ICT would help improve performance by making work flow more easily. Access to bank loans and more machinery on site and sufficient government patronage would improve performance. It concluded that better management and project planning would go a long way in improving competencies and project delivery of small sized construction firms

Helimeric porphyrinoids: Stereostructure and chiral resolution of meso -tetraarylmorpholinochlorins

The synthesis and chiral resolution of free-base and Ni(II) complexes of a number of derivatives of meso-tetraphenylmorpholinochlorins, with and without direct β-carbon-to-o-phenyl linkages to the flanking phenyl groups, is described. The morpholinochlorins, a class of stable chlorin analogues, were synthesized in two to three steps from meso-tetraphenylporphyrin. The conformations and the relative stereostructures of a variety of free-base and Ni(II) complexes of these morpholinochlorins were elucidated by X-ray diffractometry. Steric and stereoelectronic arguments explain the relative stereoarray of the morpholino-substituents, which differ in the free-base and Ni(II) complexes, and in the monoalkoxy, β-carbon-to-o-phenyl linked morpholinochlorins, and the dialkoxy derivatives. The Ni(II) complexes were all found to be severely ruffled whereas the free-base chromophores are more planar. As a result of the helimeric distortion of their porphyrinoid chromophores, the ruffled macrocycles possess a stable inherent element of chirality. Most significantly, resolution of the racemic mixtures was achieved, both by classical methods via diastereomers and by HPLC on a chiral phase. Full CD spectra were recorded and modeled using quantum-chemical computational methods, permitting, for the first time, an assignment of the absolute configurations of the chromophores. The report expands the range of known pyrrole-modified porphyrins. Beyond this, it introduces large chiral porphyrinoid π-systems that exist in the form of two enantiomeric, stereochemically stable helimers that can be resolved. This forms the basis for possible future applications, for example, in molecular-recognition systems or in materials with chiroptic properties. © 2011 American Chemical Society

Mono- and Bisquinoline-Annulated Porphyrins from Porphyrin β,β′‑Dione Oximes

An acid-induced reaction of <i>meso</i>-tetraphenyl-2-hydroxyimino-3-oxoporphyrin leads, with concomitant loss of water, to a formal electrophilic aromatic substitution of the ortho-position of the phenyl group adjacent to the oxime, forming a quinoline moiety. Owing in part to the presence of a π-extended chromophore, the resulting <i>meso</i>-triphenylmonoquinoline-annulated porphyrin (λ_max = 750 nm) possesses a much altered optical spectrum from that of the starting oxime (λ_max = 667 nm). An oxidative DDQ-induced ring-closure process is also possible, generating the corresponding <i>meso</i>-triphenylmonoquinoline-annulated porphyrin quinoline <i>N</i>-oxide, possessing a slightly shifted and sharpened UV–vis spectrum (λ_max = 737 nm). The connectivity of the chromophores was conclusively shown by NMR spectroscopy. Both ketone functionalities in <i>meso</i>-tetraphenyl-2,3-dioxoporphyrin can be converted, via the oxime and using the acid- or oxidant-induced reaction pathways, either in one step or in a stepwise fashion, to bisquinoline-annulated porphyrin (λ_max = 775 nm) and its <i>N</i>-oxide (λ_max = 779 nm), respectively. This process is complementary to a previously established pathway toward bisquinoline-annulated porphyrins. Their zinc­(II), nickel­(II), and palladium­(II) complexes are also described. Several examples of the quinoline-annulated porphyrins were crystallographically characterized, proving their connectivity and showing their conformations that are extremely distorted from planarity. The work presents a full account on the synthesis, structure, and spectroscopic properties of these classes of NIR-absorbing dyes

Factors Affecting the Competencies and Project Delivery of Small-Sized Indigenous Construction Firms in Lagos State

Every industry is prone to problems Performance is a general challenge affecting construction and most especially small-sized indigenous construction companies. The study focused on determining the likely factors affecting the competencies and project delivery of small-sized construction firms in Lagos. 60 questionnaires were designed and administered to professionals (15-Architects, 15-Builders, 15-Engineers, and 15-Quantity Surveyors) working in the construction companies in Lagos State and 48 questionnaires were retrieved. These questionnaires were analysed with SPSS and several findings were derived from this analysis. The various factors affecting the performance and project delivery at varying degrees are: high cost of plants, equipment, materials and labour, lack of skilled craftsmen, unavailability of funds, poor managerial skills, lack of government patronage, and poor communication among stakeholders. The study found out that the most prominent factors are poor managerial skills, lack of project planning and unavailability of funds. The main factors affecting the performance of small sized indigenous construction firms are based on three key elements namely time, quality and cost. These three elements when properly harnessed will increase the performance of small sized indigenous firms. The study recommended that the use of ICT would help improve performance by making work flow more easily. Access to bank loans and more machinery on site and sufficient government patronage would improve performance. It concluded that better management and project planning would go a long way in improving competencies and project delivery of small sized construction firms

Amphiphilic BODIPY-Hydroporphyrin Energy Transfer Arrays with Broadly Tunable Absorption and Deep Red/Near-Infrared Emission in Aqueous Micelles

BODIPY-hydroporphyrin energy transfer arrays allow for development of a family of fluorophores featuring a common excitation band at 500 nm, tunable excitation band in the deep red/near-infrared window, and tunable emission. Their biomedical applications are contingent upon retaining their optical properties in an aqueous environment. Amphiphilic arrays containing PEG-substituted BODIPY and chlorins or bacteriochlorins were prepared and their optical and fluorescence properties were determined in organic solvents and aqueous surfactants. The first series of arrays contains BODIPYs with PEG substituents attached to the boron, whereas in the second series, PEG substituents are attached to the aryl at the <i>meso</i> positions of BODIPY. For both series of arrays, excitation of BODIPY at 500 nm results in efficient energy transfer to and bright emission of hydroporphyrin in the deep-red (640–660 nm) or near-infrared (740–760 nm) spectral windows. In aqueous solution of nonionic surfactants (Triton X-100 and Tween 20) arrays from the second series exhibit significant quenching of fluorescence, whereas properties of arrays from the first series are comparable to those observed in polar organic solvents. Reported arrays possess large effective Stokes shift (115–260 nm), multiple excitation wavelengths, and narrow, tunable deep-red/near-IR fluorescence in aqueous surfactants, and are promising candidates for a variety of biomedical-related applications

Magnetic Circular Dichroism Spectroscopy of <i>meso</i>-Tetraphenylporphyrin-Derived Hydroporphyrins and Pyrrole-Modified Porphyrins

A large set of free-base and transition-metal 5,10,15,20-tetraphenyl-substituted chlorins, bacteriochlorins, and isobacteriochlorins and their pyrrole-modified analogues were investigated by combined UV–visible spectroscopy, magnetic circular dichroism (MCD), density functional theory (DFT), and time-dependent DFT (TDDFT) approaches and their spectral characteristics were compared to those of the parent compounds, free-base tetraphenylporphyrin <b>1H</b>_<b>2</b> and chlorin <b>2H</b>_<b>2</b>. It was shown that the nature of the pyrroline substituents in the chlorin derivatives dictates their specific UV–vis and MCD spectroscopic signatures. In all hydroporphyrin-like cases, MCD spectroscopy suggests that the ΔHOMO is smaller than the ΔLUMO for the macrocycle-centered frontier molecular orbitals. DFT and TDDFT calculations were able to explain the large broadening of the UV–vis and MCD spectra of the chlorin diones and their derivatives compared to the other hydroporphyrins and hydroporphyrin analogues. This study contributes to the further understanding of the electronic effects of replacing a pyrrole in porphyrins by pyrrolines or other five-membered heterocycles (oxazoles and imidazoles)

Nutritional and Pharmaceutical Applications of Under-Explored Knottin Peptide-Rich Phytomedicines

Phytomedicines reportedly rich in cystine knot peptides (Knottins) are found in several global diets, food/herbal supplements and functional foods. However, their knottin peptide content has largely been unexplored, notably for their emerging dual potentials at both the food and medicine space. The nutritional roles, biological targets and mechanism(s) of activity of these knotted peptides are largely unknown. Meanwhile, knottins have recently been unveiled as emerging peptide therapeutics and nutraceuticals of primary choice due to their broad spectrum of bioactivity, hyper stability, selective toxicity, impressive selectivity for biomolecular targets, and their bioengineering applications. In addition to their potential dietary benefits, some knottins have displayed desirable limited toxicity to human erythrocytes. In an effort to appraise what has been accomplished, unveil knowledge gaps and explore the future prospects of knottins, an elaborate review of the nutritional and pharmaceutical application of phytomedicines rich in knottins was carried out. Herein, we provide comprehensive data on common dietary and therapeutic knottins, the majority of which are poorly investigated in many food-grade phytomedicines used in different cultures and localities. Findings from this review should stimulate scientific interest to unveil novel dietary knottins and knottin-rich nutraceutical peptide drug candidates/leads with potential for future clinical application

<i>meso</i>-Arylporpholactones and their Reduction Products

The rational syntheses of <i>meso</i>-tetraaryl-3-oxo-2-oxaporphyrins <b>5</b>, known as porpholactones, via MnO₄^–-mediated oxidations of the corresponding <i>meso</i>-tetraaryl-2,3-dihydroxychlorins (<b>7</b>) is detailed. Since chlorin <b>7</b> is prepared from the parent porphyrin <b>1</b>, this amounts to a 2-step replacement of a pyrrole moiety in <b>1</b> by an oxazolone moiety. The stepwise reduction of the porpholactone <b>5</b> results in the formation of chlorin analogues, <i>meso</i>-tetraaryl-3-hydroxy-2-oxachlorin (<b>11</b>) and <i>meso</i>-tetraaryl-2-oxachlorins (<b>12</b>). The reactivity of <b>11</b> with respect to nucleophilic substitution by O-, N-, and S-nucleophiles is described. The profound photophysical consequences of the formal replacement of a pyrrole with an oxazolone (porphyrin-like chromophore) or (substituted) oxazole moiety (chlorin-like chromophore with, for the parent oxazolochlorin <b>12</b>, red-shifted Q_<i>x</i> band with enhanced oscillator strengths) are detailed and rationalized on the basis of SAC–CI and MNDO-PSDCI molecular orbital theory calculations. The single crystal X-ray structures of the porpholactones point at a minor steric interaction between the carbonyl oxygen and the flanking phenyl group. The essentially planar structures of all chromophores in all oxidation states prove that the observed optical properties originate from the intrinsic electronic properties of the chromophores and are not subject to conformational modulation