Use and effectiveness of Pioneer Re-entry device for subintimal true lumen re-entry: single-centre data and a review of the literature.

Introduction During subintimal angioplasty (SIA), it is not always possible to re-enter the vessel lumen due to a variety of factors. Recanalization using hydrophilic wires and catheters alone, apart from its potential technical failure, is also limited by minimal control over the re-entry point. This is frequently well beyond the point of occlusion, thus often compromising important collaterals. In order to bypass the obstruction and attain controlled re-entry into the lumen of the diseased vessel, a re-entry device (RED) may be required. This paper assesses our centre’s experience with the safety and efficacy of the Pioneer re-entry system and systematically reviews the pertinent literature. Method A single centre retrospective study of subintimal angioplasty involving the use of the Pioneer Plus intravascular guided reentry catheter was performed. Patient demographics including age, gender, risk factors, comorbidities clinical indication and complications were recorded. Lesion characteristics, including location and severity of calcification were also assessed. A systematic literature review of all reported studies where the Pioneer RED was used for iliac and lower limb revascularization was conducted by 2 of the authors using the PubMed (MEDLINE) and EMBASE databases. Results The study comprised 30 cases. Technical success was 97%. A small, quickly resolved extravasation was the only device related complication. These results are in line with the systematic review which identified 16 studies using the Pioneer RED, reporting a technical success rate of 87.4–100% (median = 100%) and complication rate of 0–25.8% (median = 0%). However, due to heterogeneity in definitions of technical success, data was not pooled

Determinants of length of hospitalization in a federal psychiatric hospital in Nigeria

Objective: The present study aims to determine the association between clinical-demographic variables and length of stay of patients admitted into Federal Psychiatric Hospital, Calabar.Design: Retrospective review of case records.Methods: 280 case records of patients (discharged from September 1st, 2015 to August 31st, 2016) were assembled for review, out of which twelve cases were excluded for various reasons. Clinical and demographic data collected from the remaining 268 case records were subjected to univariate and multivariate analyses to determine variables associated with prolonged length of stay.Results: Mean length of stay was 56.2 ± 40.9 and the commonest clinical diagnosis was schizophrenia (45.9%). Although gender, age, marital status and clinical diagnoses tended to influence length of stay, gender (p =0.007) and clinical diagnosis of schizophrenia (p =0.044) were the only variables that significantly predicted prolonged length of stay.Conclusion: We found that gender and clinical diagnoses were important determinants of length of stay. If validated in future studies, these factors may help in accurate identification of cases at risk of prolonged hospitalization and act as guide to clinicians who may need to optimize intervention strategies early enough in managing such cases.Keywords: Psychiatric hospitalization, Length of stay, Prolonged hospitalization, Psychiatric patients, Calaba

ESTIMATION OF GLOBAL SOLAR RADIATION AT CALABAR USING TWO MODELS

In this study, the estimation of global solar radiation with Meteorological parameters at Calabar- Nigeria latitude 40N and longitude 80 E were carried out. The daily mean temperature and relative humidity for seventeen years (1991 to 2007) from Nigerian Meteorological Agency, Federal Ministry of Aviation, Oshodi, Lagos were used. The global solar radiation data were collected courtesy of Renewable Energy for Rural Industrialization and Development in Nigeria. Two models (multiple regression and artificial neural network) were used for the estimation. Comparing the graphs of correlation equation 4 and 5, and equation 6 and 7 of the first model, it is obvious that the first order correlation has better estimation power. Looking at the overview of all the Figures (1 -5A), is it is clear that the two models used in this study has estimation capacity, but Figure 5A shows better correlation with the measured values, which indicates that artificial neural network model is a better model for estimation. Therefore has been recommended for global solar radiation estimation at Calabar and its environs with similar weather condition. Alternatively, first order regression should be use for estimation in the absent of artificial neural network. Keywords: artificial neural network, regression, model, global solar radiatio

Estimation of Global Solar Radiation in Onitsha and Calabar Using Empirical Models

Understanding solar radiation data is essential for modelling solar energy systems. The purpose of the present study was to estimate global solar radiation on horizontal surface using meteorological parameters for a period of eleven years (1996 "“ 2006). Monthly average global solar radiation, H has been estimated for Onitsha and Calabar, Nigeria using predicting models generated by simple linear and multiple regression analyses. The models included a one variable model with relative humidity as the independent variable and two three-variable models correlating H with relative humidity and each of average temperature, cloudiness index and number of sunshine hours. The values of the global solar radiation estimated by the models and the measured solar radiation were tested using the mean bias error (MBE), root mean square error (RMSE) and mean percentage error (MPE) statiscal techniques. The values of the correlation coefficient (CC) were also determined for each model. The model that indicate a good agreement between the measured and estimated values for Onitsha and Calabar are  and  respectively. The developed models can be used for estimating global solar radiation in Onitsha and Calabar and other locations with similar climatic factors

Forage Yield and Nutritive Quality of Haulm from Dual-Purpose Cowpea (\u3ci\u3eVigna unguiculata\u3c/i\u3e L Walp) Cultivars for Dry Season Feeding in Nigeria

The availability of high quality forage especially during the dry season remains a major challenge to ruminant livestock production in Nigeria and many parts of West Africa. Due to the prevailing mismatch between livestock population and supply of feed resources in the arid and semi arid Nigeria, the humid forest zone represents a potential source for crop residues, especially during the dry season due to longer rainfall duration and suitable climate. This study was conducted to evaluate forage yield and nutritive quality of haulm from selected dual purpose cowpea (Vigna unguiculata L. Walp.) cultivars in the humid rain forest zone of Nigeria. The forage and pod yields of twenty cultivars were evaluated in two cropping seasons of 2012 and 2013, in a randomized complete block design with three replications. Subsequently, five dual-purpose cultivars were selected based on forage and pod yields from previous trial, for determination of chemical and fibre compositions. The results revealed significant (p \u3c 0.05) differences in pod and forage yields among the twenty cowpea cultivars, with mean yields ranging from 0-1.5 t ha-1 and 0.1-4.5 t ha-1 for pod and forage respectively. The results also showed significant (p \u3c 0.05) differences in crude protein, ether extract, and non-fibre carbohydrates (NFC) contents amongst the five selected cultivars. The selected cultivars are recommended as dual-purpose cowpea for the zone. The result reveal wide implications for commercial production, processing and packaging of cowpea and other related forage crops for sale in Northern Nigeria where demand for dry season feedstuff outstrips supply. In addition, availability of feedstuff during the dry season is capable of promoting sedentarization of nomadic pastoralists and the attendant conflict associated with that system of livestock management

Study of the Effects of Thermal Annealing on the Optical Band Gap of Nanocrystalline CoO Thin Films Prepared by Chemical Bath Deposition.

Nanocrystalline films of cobalt oxide have been prepared on glass slides by chemical bath deposition process. For deposition of CoO thin films, cobaltous chloride [CoCl2.6H2O] was used as cationic and ammonia [NH3] as anionic precursor in aqueous medium. In this process NaOH was used as complexing agent. X-ray diffraction, scanning electron microscopic [SEM] analysis have been used to study the films’ crystal structures, optical and solid state properties. We hereby present the effects of thermal annealing on the optical band gap of CoO thin films. The optical transition in the films is direct one. For the as- deposited film, the band gap is 2.1eV. This later decreased to 2.08eV, so that increased thermal annealing reduces the optical band gap of CoO. However,the energy gap cannot be said to be dependent on the annealing temperatures. These films could be used as  photovoltaic cells, sensors light emitting diodes and also in biomedical imaging. Key Words: Nanocrystalline CoO, Chemical Bath Deposition, Band Gap and                               Thermal Annealing

Approaches to modelling fireside corrosion of superheater / reheater tubes in coal and biomass fired combustion power plants

The combustion of coal and biomass fuels in power plants generates deposits on the surfaces of superheater / reheater tubes that can lead onto fireside corrosion. This type of materials degradation can limit the lives of such tubes in the long term, and better methods are needed to produce predictive models for such damage. This paper reports on four different approaches that are being investigated to tackle the challenge of modelling fireside corrosion damage on superheaters / reheaters: (a) CFD models to predict deposition onto tube surfaces; (b) generation of a database of available fireside corrosion data; (c) development of mechanistic and statistically based models of fireside corrosion from laboratory exposures and dimensional metrology; (d) statistical analysis of plant derived fireside corrosion datasets using multi-variable statistical techniques, such as Partial Least Squares Regression (PLSR). An improved understanding of the factors that influence fireside corrosion is resulting from the use of a combination of these different approaches to develop a suite of models for fireside corrosion damage

Inhibition effect of Vernonia amygdalina extract on the corrosion of mild steel reinforcement in concrete in 0.2 M H2SO4 Environment

Inhibition effect of Vernonia amygdalina (bitter leaf) extract on the corrosion behaviour of embedded mild steel rebar in concrete immersed in 0.2% H2SO4 solution was investigated by potential measurement, pH and gravimetric methods using the extracts concentrations of 25, 50, 75, and 100%. The results were further analysed using the two-factor ANOVA test. Potential measurement was performed using a digital voltmeter and a copper/copper sulphate reference electrode. Compressive strength of each block sample was determined after the experiments. Weight loss values were obtained from the gravimetric method, and the inhibitor efficiency was computed from the corrosion rate of each of the tested samples. Results showed that varied concentration of V. amygdalina and the test exposure time significantly affect both the corrosion potential of embedded steel rebar in concrete and the pH of the medium. The extracts gave appreciable corrosion inhibition performance of the embedded steel rebar at 25 and 50% concentrations with the weight loss of 500 (0.5 g) and 400 mg (0.4 g) and corrosion rates values of 0.000240 and 0.000180 mm/ yr, respectively. The highest inhibition efficiency (60.68%) was achieved at 50 and 39.94% at 25% concentrations, respectively. The 100 and 75% concentrations gave negative inhibitor values of �51.52 and �20.11%. The ANOVA test confirmed the results at 95% confidence, and further showed that concentration of V. amygdalina had greater effect on potential and pH measurement

Nanoscale Visualization of Elastic Inhomogeneities at TiN Coatings Using Ultrasonic Force Microscopy

Ultrasonic force microscopy has been applied to the characterization of titanium nitride coatings deposited by physical vapor deposition dc magnetron sputtering on stainless steel substrates. The titanium nitride layers exhibit a rich variety of elastic contrast in the ultrasonic force microscopy images. Nanoscale inhomogeneities in stiffness on the titanium nitride films have been attributed to softer substoichiometric titanium nitride species and/or trapped subsurface gas. The results show that increasing the sputtering power at the Ti cathode increases the elastic homogeneity of the titanium nitride layers on the nanometer scale. Ultrasonic force microscopy elastic mapping on titanium nitride layers demonstrates the capability of the technique to provide information of high value for the engineering of improved coatings