Impact of Infrastructure on Productivity of Small and Medium Enterprises in Nigeria

The study investigates the link between infrastructure and productivity of small and medium enterprises (SMEs) in Nigeria Following the Engle and Granger two-step approach to cointegration and employing quarterly time series for the Nigerian economy over the period 1980 to 2017. We found long-run equilibrium relationship between infrastructure and small and medium enterprises output in Nigeria over the period investigated. Particularly, electricity infrastructure impacted most negatively and significantly on SMEs output with a unit change in electricity output causing SMEs output to drop by about 0.2units in the short run. The contribution of water resources and transport infrastructure have not been significant on SMEs productivity. The error correcting term indicates that about 7.33E-09 of the disequilibrium between selected infrastructure and SMEs output in the economy is being restored annually. The conclusion is that the output of SMEs in the country has been constrained by infrastructure gap and this has limited the growth capacity of the Nigerian economy. Policies that will ensure that the SMEs play their roles in the economy must be hatched. In addition, the government, in collaboration with relevant stakeholders may consider creating SMEs zones in every State of the country and provide needed infrastructure within the zone such that SMEs can enjoy economies of agglomeration. Keywords: Infrastructure, SMEs, Economic growth, Employment, Wealth creation JEL H54 DOI: 10.7176/RHSS/9-2-0

On Comparison of Exponential and Hyperbolic Exponential Growth Models in Height/Diameter Increment of PINES (Pinus caribaea)

A new tree growth model called the hyperbolic exponential nonlinear growth model is suggested. Its ability in model prediction was compared with the Malthus or exponential growth model an approach which mimicked the natural variability of heights/diameter increment with respect to age and therefore provides more realistic height/diameter predictions as demonstrated by the results of the Kolmogorov Smirnov test and Shapiro-Wilk test. The mean function of top height/Dbh over age using the two models under study predicted closely the observed values of top height/Dbh in the Hyperbolic exponential nonlinear growth models better than the ordinary exponential growth model without violating most of the assumptions about the error term

Aqueous Extracts of Anogeissus Leiocarpus (DC.) Guill. & Perr. and Terminalia Glaucescens Planch ex Benth. Inhibited Helicobacter Pylori

The inhibitory effects of methanol, dichloromethane and aqueous extracts of Anogeissus leiocarpus (DC.) Guill. & Perr. and Terminalia glaucescens Planch ex Benth. (family Combretaceae) reportedly used in the treatment of gastrointestinal diseases including stomach disorder and ulcer are investigated to ascertain and justify their use in traditional medicine. Nineteen (19) strains of Helicobacter pylori including 18 clinical isolates and Helicobacter pylori ATCC 43504 were used in this study. The susceptibility and minimum inhibitory concentration (MIC) testing were performed using the agar dilution procedure guidelines of the Clinical and Laboratory Standards Institute. bactericidal studies were performed using viable counting techniques. The MIC and MBC values for the susceptible strains ranged from 0.08 mg/mL to 1.25 mg/mL and 0.16 mg/mL - 2.5 mg/mL respectively Bactericidal study revealed a dose- and time-dependent decline in surviving population of H. pylori AB005 at concentrations equivalent to MIC, 2 x MIC and 4 x MIC (Figures 1-4). The aqueous extracts of Anogeissus leiocarpus stem bark and root gave a 100% kill at 6-hour exposure time with concentration equivalent to 4x MIC (i.e. 0.32mg/mL). The antimicrobial activities demonstrated by extracts of the plants on Helicobacter pylori revealed the presence of therapeutically potent antibacterial compounds and thus justify the use of these medicinal plants for the treatment of peptic ulcer disease. Keywords: Anogeissus leiocarpus (DC.) Guill. & Perr.; Terminalia glaucescens Planch ex Benth.; Helicobacter pylori; peptic ulcer disease; bactericidal activit

Cryo-STEM-EDX spectroscopy for the characterisation of nanoparticles in cell culture media

We present a study of barium titanate nanoparticles dispersed in cell culture media. Scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy was undertaken on samples prepared using both conventional drop casting and also plunge freezing and examination under cryogenic conditions. This showed that drying artefacts occurred during conventional sample preparation, whereby some salt components of the cell culture media accumulated around the barium titanate nanoparticles; these were removed using the cryogenic route. Importantly, the formation of a calcium and phosphorus rich coating around the barium titanate nanoparticles was retained under cryo-conditions, highlighting that significant interactions do occur between nanomaterials and biological media

Nanoparticle corona artefacts derived from specimen preparation of particle suspensions

Progress in the implementation of nanoparticles for therapeutic applications will accelerate with an improved understanding of the interface between nanoparticle surfaces and the media they are dispersed in. We examine this interface by analytical scanning transmission electron microscopy and show that incorrect specimen preparation or analysis can induce an artefactual, nanoscale, calcium phosphate-rich, amorphous coating on nanoparticles dispersed in cell culture media. We report that this ionic coating can be induced on five different types of nanoparticles (Au, BaTiO3, ZnO, TiO2 and Fe2O3) when specimen preparation causes a significant rise in pH above physiological levels. Such a pH change reduces ionic solubility in the suspending media to permit precipitation of calcium phosphate. Finally, we demonstrate that there is no indication of a calcium-phosphorus-rich coating on BaTiO3 nanoparticles suspended in culture media when prepared without alteration of the pH of the suspending media and imaged by cryo-STEM. Therefore we recommend that future reports utilising nanoparticles dispersed in cell culture media monitor and report the pH of suspensions during sample preparation

Structural Transformations and Spin‐Crossover in [FeL2]2+ Salts (L = 4‐{tertbutylsulfanyl}‐2,6‐di{pyrazol‐1‐yl}pyridine) − the Influence of Bulky Ligand Substituents

4‐(Tert‐butylsulfanyl)‐2,6‐di(pyrazol‐1‐yl)pyridine (L) was obtained in low yield from a one‐pot reaction of 2,4,6‐trifluoropyridine with 2‐methylpropane‐2‐thiolate and sodium pyrazolate in a 1:1:2 ratio. The materials [FeL2][BF4]2·solv (1[BF4]2·solv) and [FeL2][ClO4]2·solv (1[ClO4]2·solv; solv = MeNO2, MeCN or Me2CO) exhibit a variety of structures and spin‐state behaviors including thermal spin‐crossover (SCO). Solvent loss on heating 1[BF4]2·xMeNO2 (x ≈ 2.3) occurs in two steps. The intermediate phase exhibits hysteretic SCO around 250 K, involving a “reverse‐SCO” step in its warming cycle at a scan rate of 5 Kmin‒1. The reverse‐SCO is not observed in a slower 1 Kmin‒1 measurement, however, confirming its kinetic nature. The final product [FeL2][BF4]2·0.75MeNO2 was crystallographically characterized, and shows abrupt but incomplete SCO at 172 K which correlates with disorder of an L ligand. The asymmetric unit of 1[BF4]2·yMe2CO (y ≈ 1.6) contains five unique complex molecules, four of which undergo gradual SCO in at least two discrete steps. Low‐spin 1[ClO4 ]2·0.5Me2CO is not isostructural with its BF4− congener, and undergoes single‐crystal‐to‐single‐crystal solvent loss with a tripling of the crystallographic unit cell volume, while retaining the P ‐1 space group. Three other solvate salts undergo gradual thermal SCO. Two of these are isomorphous at room temperature, but transform to different low‐temperature phases when the materials are fully low‐spin

Synthesis and magnetic characterizations of manganite-based composite nanoparticles for biomedical applications

We report chemically synthesized highly crystalline lanthanum strontium manganite (LaSrMnO3) and Eu-doped Y2O3 and their composites. The synthesis yields nanoparticles of size 30–40 nm. Magnetic measurements performed on nanoparticles and composites show magnetic transition at about 370 K with a superparamagnetic behavior at room temperature. The ferromagnetic resonance studies of the nanoparticles show large linewidth due to surface strains. The composite nanoparticles also display luminescent behavior when irradiated with ultraviolet light. The manganites as well their composite with the luminescent nanoparticles may be very useful for biomedical applications