Emergency Department Time Course for Mild Traumatic Brain Injury Workup

Introduction: Mild traumatic brain injury (mTBI) is a common cause for visits to the emergency department (ED). The actual time required for an ED workup of a patient with mTBI in the United States is not well known. National emergency medicine organizations have recommended reducing unnecessary testing, including head computed tomography (CT) for these patients.10 Methods: To examine this issue, we developed a care map that included each step of evaluation of mTBI (Glasgow Coma Scale Score 13-15) – from initial presentation to the ED to discharge. Time spent at each step was estimated by a panel of United States emergency physicians and nurses. We subsequently validated time estimates using retrospectively collected, real-time data at two EDs. Length of stay (LOS) time differences between admission and discharged patients were calculated for patients being evaluated for mTBI. Results: Evaluation for mTBI was estimated at 401 minutes (6.6 hours) in EDs. Time related to head CT comprised about one-half of the total LOS. Real-time data from two sites corroborated the estimate of median time difference between ED admission and discharge, at 6.3 hours for mTBI. Conclusion: Limiting use of head CT as part of the workup of mTBI to more serious cases may reduce time spent in the ED and potentially improve overall ED throughput

The Impact of Oil Price and Oil Volatility Index (OVX) on the Exchange Rate in Sub-Saharan Africa:Evidence from Oil Importing/Exporting Countries

The Theory demonstrates that oil price and oil volatility (OVX) are significant determinants of economic activity; however, studies seldom consider both variables in the oil–exchange rate nexus and ignore the distributional heterogeneity of the exchange rate. We investigate their joint effect and employ both the quantile regression and Markov switching models to address this. We differentiate between positive/negative shocks and control for the effect of the global financial crisis in 2008 and the COVID-19 pandemic in 2020. We observe that OVX shocks significantly impact the exchange rate for all countries whereas, oil price shocks only affect the exchange rate of oil importing countries. Rising (falling) OVX causes the local currency to depreciate (appreciate). The impact of rising or falling OVX is the same for oil importing and oil exporting countries whereas the impact of rising and falling oil price varies. The impact of oil price and OVX on exchange rate is affected by market conditions. The exchange rate responds to oil price and OVX mostly at lower quantiles (bearish markets) for all countries, which reveals investors sensitivity. In contrast, a weak to no significant response is observed at the higher quantiles (bullish market). Our results are robust in model selection (Markov switching models)

The Effect of Different Fracturing Fluids on the Productivity of Multi-Staged Fractured Marcellus Shale Horizontal Wells

While hydraulic fracturing has undeniably improved the production from oil and gas reservoirs, this technology is not without limitations. The primary hurdles lie in the areas of proppant transport, fluid rheology, and stress management. Despite the extensive research conducted in this domain, there remains a considerable amount of work to be done for comprehensive solutions that account for the complex interactions among fracturing fluid, proppant distribution, and geomechanical conditions. Achieving this will then make room for a holistic and efficient hydraulic fracturing strategy. This study addresses the above-mentioned problem by examining the impact of fluid type on proppant transport and distribution leading to productivity improvement for a multi-staged fractured Marcellus Shale horizontal well. In addition, stress shadow impact and the extent to which various fracture properties contribute to production are evaluated. The findings can be used to enhance fracture treatment design in the Marcellus shale through optimum fluid selection and stage spacing to reduce the impact of the stress shadow. Available core plug measurements, well logs, and image logs were analyzed to determine the shale petrophysical and geomechanical properties, including natural fracture (fissure) distribution, to develop a horizontal Marcellus Shale well model. Available laboratory measurements and published data were analyzed to determine the gas adsorption characteristics and the shale compressibility. The impact of the shale compressibility as a function of net stress was then incorporated into the model by developing multipliers for fissure and matrix permeability as well as the hydraulic fracture conductivity. The hydraulic fracture properties estimated using the GOHFER 3D software were incorporated into the developed reservoir model and ultimately, the impact of fluid type and stress shadow on proppant transport and the gas production were investigated. The reservoir model’s credibility was confirmed by a close match between the actual and predicted production. The fracture heights induced by all the fluids remained within the pay zone and the entire fracture height contributed to the production. High Viscosity Friction Reducer (HVFR) resulted in relatively larger fracture volume (with increased fracture height) in comparison to Slickwater, Crosslinked Gel, and Hybrid fluids thus resulting in improved productivity. The cross-linked gel also improved productivity but was found to be inferior to HVFR. High Percentage Reduction indicated the adverse impact of stress shadow on hydraulic fracture properties and gas production. The impact of the stress shadow on the production is, however, more pronounced during early production due to higher production rates

Surface Modification of Melt Extruded Poly(ε-caprolactone) Nanofibers: Toward a New Scalable Biomaterial Scaffold.

A photochemical modification of melt-extruded polymeric nanofibers is described. A bioorthogonal functional group is used to decorate fibers made exclusively from commodity polymers, covalently attach fluorophores and peptides, and direct cell growth. Our process begins by using a layered coextrusion method, where poly(ε-caprolactone) (PCL) nanofibers are incorporated within a macroscopic poly(ethylene oxide) (PEO) tape through a series of die multipliers within the extrusion line. The PEO layer is then removed with a water wash to yield rectangular PCL nanofibers with controlled cross-sectional dimensions. The fibers can be subsequently modified using photochemistry to yield a "clickable" handle for performing the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction on their surface. We have attached fluorophores, which exhibit dense surface coverage when using ligand-accelerated CuAAC reaction conditions. In addition, an RGD peptide motif was coupled to the surface of the fibers. Subsequent cell-based studies have shown that the RGD peptide is biologically accessible at the surface, leading to increased cellular adhesion and spreading versus PCL control surfaces. This functionalized coextruded fiber has the advantages of modularity and scalability, opening a potentially new avenue for biomaterials fabrication

An investigation into strategies and policies to expand the textile industry in Ghana: A case study using Akosombo Textile Limited (ATL) and Ghana Textile Product (GTP)

Thesis submitted to the Department of Business Administration, Ashesi University College, in partial fulfillment of Bachelor of Science degree in Business Administration, April 2011The Ghana Textile industry was part of several industries set up in the late 1960s by Ghana's first president, Dr. Kwame Nkrumah, in an attempt to make the economy self-sufficient. By the mid 1970s, there were 40 medium to large scale textile companies in Ghana. The industry's productivity peaked in this same period achieved a total output of 130 million yards, plant utilization capacity of 60% and employed about 25,000 people (Quartey, 2006). In the mid 1980s, however, the Ghana textile industry's performance started declining. Several researchers have attributed this decline to a Trade Liberalization policy that was implemented at the time. Paradoxically, trade Liberalization is the removal of trade barriers such as tariffs, quotas and other non-tariff restrictions on trade. This makes an economy freer and more open to fair trade with other countries (Krugman and Obstfeld, 2006). Today the Ghana textile industry employs some 3000 people with total industry output of 40 million yards (Zizer, 2010). This research study explores the current problems facing the Ghana textile industry using Ghana Textile Print (GTP) and Akosombo Textile Limited (ATL) as case studies. The study provides feasible and relevant measures and strategies to policy makers (government) and textile manufacturers to stimulate the moribund textile industry. In particular government should subsidize manufacturing costs, assist textile firms to obtain credit and strategically institute trade barriers. It is imperative that government and textile manufacturers understand and implement the recommendations made in this research project to revive Ghana's currently almost non-existent textile industry.Ashesi University Colleg

Solid-State Processing Approach to Enhance the Mechanical Properties of Polypropylene

Agenda: Background; Research Problem; Methodology; Results and Discussion; Conclusions

A Solid-State Processing Approach to Enhance the Mechanical Performance of Polyolefins

This study aims to present and evaluate the use of solid-state processing for improving the mechanical properties of polyolefins. Isotactic polypropylene (i-PP) was selected to be studied due to its inferior mechanical properties in comparison to common plastics such as polyethylene (PET) and polyvinyl chloride (PVC). Recently, i-PP has garnered attention due to its attributes such as low-cost and recyclability. However, it requires additional processing to improve its mechanical performance. In this study, cryomilling was used to introduce various concentrations (0.2 - 1 wt. %) of diparamethyldibenzyldiene sorbitol (MDBS), as reinforcing agent, into the i-PP polymer. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the structural and thermal characteristics of the generated blends. Compression molding was utilized to fabricate thin films, and subsequently subjected to tensile testing using a universal testing machine. Results from DSC indicate the ability of cryomilling to generate a homogenous blend by indicating an increase in the crystallization temperature. Moreover, results from the tensile tests showed an increase in tensile strength. The improvements in the mechanical properties of polyolefins with the addition of sorbitol-derivatives can be attributed to the reduction in the average spherulite size of the polymer

Developing an optimization model for efficient distribution of petroleum products: A case study of Tema Oil Refinery (TOR)

Thesis submitted to the Department of Business Administration, Ashesi University College, in partial fulfillment of Bachelor of Science degree in Management Information Systems, April 2010This research explores linear programming optimization models for distributing products by tankers in a land transportation system. Tema Oil Refinery (TOR) is used as a case study. The transportation problem is of great economic significance to the Government of Ghana, whose economy is traditionally dominated to a large extent by the oil sector. Any enhancement in the existing transportation procedure has the potential for significant cost savings for the Ghanaian economy. A linear programming model for the TOR problem is constructed in this paper. A set of nodes and arcs is used to form the network, and the decision variables are the different transportation routes. The objective function minimized is formed by summing the products of the decision variables and their corresponding cost coefficients. The constraints of the model include capacity at the depots and the demands of the Oil Marketing Companies (OMCs). The scope of this research covered five (5) OMCs across three (3) capital cities namely; Accra, Kumasi and Takoradi. The resulting linear formulation is greatly simplified and it was solved using Solver (an in-built optimisation tool) in Microsoft EXCEL.Ashesi University Colleg