Flow Model Selection for Water Soluble Polymer Solutions

This research deals with the effect of type and concentration of different polymer solutions on rheological behavior and apparent viscosity. All polymers studied in this work are water soluble, which are: XC-polymer, Carboxymethyl cellulose (two types), Hydroxyethyl cellulose and Polyvinyl alcohol. 55 experiments were performed with different polymer types and concentrations at 30 C ( 1 C). By using the Solver Add-in in Microsoft Excel®, the power law flow model was found to be the best fits the experimental results. The apparent viscosity of each polymer used at different concentrations was decreased with shear rates. It was found that XC-polymer solutions have higher shear stresses than other polymers. Also it was found that XC-polymer solutions have a higher viscosity, and its viscosity decreases much more than other polymer solutions used in this study

Effect of Type and Concentration of Different Water Soluble Polymer Solutions on Rheological Properties

This research deals with experimental study of the effect of concentration of polymer solutions on rheological properties. All polymers studied in this work are water soluble, which are: XC-polymer, Carboxymethyl cellulose (two types), Hydroxyethyl cellulose and Polyvinyl alcohol. The rheological properties of these polymer solutions was investigated using a Couette coaxial cylinder rotational viscometer ( Fann model 35A ), by measuring shear stresses versus shear rates (i.e. the flow curve). 55 experiments were performed with different polymer solutions concentrations at temperature 30 C ( 1 C). It was found that as polymer concentration increased, the flow behavior index (n) decreased and the consistency index (k) increased. This behavior reflects the fact that as polymer concentration increases the solution become far from Newtonian fluid. Correlations were found which describe the effect of polymer concentration on n and k (for each polymer used in this study) and presented in a linear and exponential form respectively

Modelling the Ghanaian Inflation Rates Using Interrupted Time Series Analysis Approach

The article considers the application of interrupted time series analysis to model yearly inflation rates in Ghana from 1996 to 2006. This article, therefore, explored the effectiveness of the economic policy intervention in the year 2001 on the inflation rate time series for the period 2001 to 2006 using the interrupted time series experiment. We also sort to use this model to make forecasts of future values. To achieve this objective, yearly inflation rates for the period were obtained from Bank of Ghana (BoG). The Box-Jenkins Autoregressive Integrated Moving Average (ARIMA) method with interruption was employed in analyzing the data using Statistical Product for Service Solution (SPSS) version 20. It was found that the rate of inflation in Ghana can be fitted with an autoregressive model of order one, i.e. AR (1) model. From the results of the tests of the difference between the means before and after intervention, as well as the interrupted time series experiment, indicated that the intervention successfully reduced the rate of inflation in the Ghana’s economy. Keywords: Inflation, Interrupted Time Series, Box-Jenkins Method

Angiomyofibroblastoma: Imaging and histopathology of a rare benign mesenchymal tumor

Angiomyofibroblastomas, aggressive angiomyxomas and cellular angiofibromas are rare mesenchymal tumours with many overlapping radiological, histopathological and immunohistochemical features. Amongst these tumours angiomyofibroblastoma is relatively benign mesenchymal tumour with very low chances of recurrence. It is clinically confused with bartholin gland cyst due to its well demarcated and smooth appearance. Due to overlapping histopathological features its very difficult even for experienced pathologists to differentiate between these mesenchymal tumours. Earlier desmin reactivity was thought to be specific for angiomyofibroblastoma but recently many aggressive angiomyxomas have also been found to be positive for desmin. Ultrasound, computed tomography and magnetic resonance imaging may be useful in diagnosis and ruling out more sinister malignancies. A well demarcated lesion with characteristic histopathological appearance of alternating hypo and hypercellular edematous regions with abundant blood vessels and stromal cells with dispersed chromatin is usually seen in angiomyofibroblastoma. Immunohistochemistry may further help in diagnosis. We here report a case of vaginal angiomyofibroblastoma. The diagnosis was made on the basis of imaging and was confirmed by histopathology and immunohistochemistry.Keywords: Histopathology and immunohistochemistry; imaging; mesenchymal tumours; vaginal angiomyofibroblastom

Studying the Factors Affecting the Settling Velocity of Solid Particles in Non-Newtonian Fluids

The aim of this research is to study the factors affecting the settling velocity (V S ) in Non-Newtonian fluids which are the rheological properties, concentrations of non-Newtonian fluids, particle shape and size. An experimental apparatus was designed and built, which consists of Perspex pipe of length of 160 cm. and inside diameter of 7.8 cm. to calculate the settling velocity, also electronic circuit was designed to calculate the falling time of particles through fluid. Two types of solid particles were used; glass spheres and crushed rocks as irregularly shaped particles with different diameters and compared with each other. The concept of equivalent spherical diameter (D S ) was used to calculate the diameters of irregularly shaped particles. The settling velocity was calculated for Non-Newtonian fluids which represented by Power- Law fluid. Two types of polymers were used, Carboxy Methyl Cellulose with concentrations of (3.71, 5, 15 and 17.5) g/l and polyacrylamide with concentrations of (2, 4 and 6) g/l. The results showed that the settling velocity decreased when fluid becomes far from Newtonian behavior (flow index n decreased) and also when concentrations of polymer solutions increased, also, the settling velocity increased with particle diameter or volume. Three sets of equations were concluded; the first relates settling velocity with flow index (n), the second relates settling velocity with concentrations, and the third relates settling velocity with particle diameter

Electronic Patient Record for Dental Charting

The use of electronic patient records has a great positive potential to improve clinical practice and patient safety. These improvements can be realized through improved legibility and communication, standardized documentation, streamlined storage and consistent reporting. This paper addresses the development of an electronic patient record for dental charting as an alternative means towards a user-friendly and patient-centered dental environment. It considers prevalent dental charting practices, proposes a patient dental database and presents a dental charting application prototype, capable of capturing and displaying patient dental records. Data from this database is mapped and can be further manipulated through the patient's interactive dental chart. This interactivity not only offer quick-to-comprehend interfaces, but also reduces miscommunicationss. It will affect positively the legibility of dental records, enable a standardized documentation and a more consistent reporting

Investigating the blood-host plasticity and dispersal of Anopheles coluzzii using a novel field-based methodology

Background: The biting behaviour and dispersal of insect vectors in the field underlies the transmission of many diseases. Here, a novel collection methodology coupled with the molecular analysis of blood-meal sources and digestion rates is introduced with the aim of aiding the understanding of two critical and relatively understudied mosquito behaviours: plasticity in blood-host choice and vector dispersal. Results: A collection strategy utilising a transect of mosquito traps placed at 50 m intervals allowed the collection of blood-fed Anopheles coluzzii from a malaria-endemic village of southern Ghana where human host availability ranged from zero (a cattle pen), increasing until humans were the dominant host choice (the middle of the village). Blood-meal analysis using PCR showed statistically significant variation in blood-meal origins for mosquitoes collected across the 250 m transect: with decreasing trend in Bovine Blood Index (OR = 0.60 95% CI: 0.49-0.73, P < 0.01) and correspondingly, an increasing trend in Human Blood Index (OR = 1.50 95% CI: 1.05-2.16, P = 0.028) as the transect approached the village. Using qPCR, the host DNA remaining in the blood meal was quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. Time since blood meal was consumed and the corresponding distance the vector was caught from its blood-host allowed the estimation of An. coluzzii dispersal rates. Within 7 hours of feeding, mosquitoes typically remained within 50 m of their blood-host but at 60 hours they had dispersed up to 250 m. Conclusions: Using this methodology the remarkably small spatial scale at which An. coluzzii blood-host choice can change was demonstrated. In addition, conducting qPCR on host blood from field-caught mosquitoes and calibrating with timed experiments with colonised mosquitoes presents a novel methodology for investigating the dispersal behaviour of vectors. Future adaptations to this novel method to make it broadly applicable to other types of setting are also discussed.Universiteit Stellenbosch, National Institute for Health Research, National Health and Medical Research Counci

Peripartum Pulmonary Embolism

Pregnancy and peripartum increase the risk of venous thromboembolism (VTE) by many folds. Interestingly, the VTE is more common during the pregnancy, whereas the pulmonary embolism is more frequent in postpartum period. There are various risk factors for the VTE and pulmonary embolism in these patients. The important risks are improper thromboprophylaxis, obesity, and multigravida. The clinical parameters and the d-dimer are not used for diagnosis of thromboembolism during pregnancy and in the postpartum period. The compression ultrasonography (CUSG) is commonly used for VTE diagnosis; for the pulmonary embolism diagnosis, one has to consider the radiation hazard to the fetus as well as to the mothers. Ventilation/perfusion scan is the imaging of choice for patient who has respiratory signs with normal chest radiograph. If chest X-ray is abnormal with suspicion of peripartum pulmonary embolism (PPE), the choice should be computed tomographic angiography. Heparin and its derivatives remained the anticoagulation of choice for the treatment of VTE as well as the PPE, as it is a shorter acting, easy to reverse with protamine sulfate. Proper thromboprophylaxis is the key for prevention of VTE and peripartum pulmonary embolism