Faculty Scholarly Publications

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    Prodigiosin-loaded electrospun nanofibers scaffold for localized treatment of triple negative breast cancer
    (Elsevier, 2020-09) Akpan, U. M.; Pellegrini, M.; Obayemi, J. D.; Ezenwafor, T.; Browl, D.; Ani, C. J.; Yiporo, D.; Salifu, A.; Dozie-Nwachukwu, S.; Odusanya, S.; Freeman, J.; Soboyejo, W. O.
    Hybrid composite nanofibers, with the potential to enhance cell adhesion while improving sustained drug release profiles, were fabricated by the blend electrospinning of poly(d,l-lactic-co-glycolic acid) (PLGA), gelatin, pluronic F127 and prodigiosin (PG). Scanning Electron Microscopy (SEM) images of the nanofibers revealed diameters of 1.031 ± 0.851 μm and 1.349 ± 1.264 μm, corresponding to PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. The Young's moduli were also determined to be 1.446 ± 0.496 kPa and 1.290 ± 0.617 kPa, while the ultimate tensile strengths were 0.440 ± 0.117 kPa and 0.185 ± 0.480 kPa for PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. In-vitro drug release profiles showed initial (burst) release for a period of 1 h to be 26.000 ± 0.004% and 16.000 ± 0.015% for PLGA/Ge and PLGA/Ge-F127 nanofibers, respectively. This was followed by 12 h of sustained release, and subsequent slow sustained release of PG from the composite nanofibers. The cumulative release of PG (for three days) was determined to be 82.0 ± 0.1% for PLGA/Ge and 49.7 ± 0.1% for PLGA/Ge-F127 nanofibers. The release exponents (n) show that both nanofibers exhibit diffusion-controlled release by non-Fickian (zeroth order) and quasi-Fickian diffusion in the initial and sustained release regimes, respectively. The suitability of the composite nanofibers for supporting cell proliferation and viability, as well as improving sustained release of the drug were explored. The in-vitro effects of cancer drug (PG) release were also studied on breast cancer cell lines (MCF-7 and MDA-MB-231 cells). The implications of the results are discussed for the potential applications of drug-nanofiber scaffolds as capsules for localized delivery of chemotherapeutic drugs for the treatment of triple negative breast cancer.
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    Effect of hands-on science activities on Ghanaian student learning, attitudes, and career interest: A preliminary control study
    (Global Journal of Transformative Education, 2020-12) Beem, Heather
    A quasi-experimental study was carried out with 309 Form 3 students across 9 public Junior High Schools in the Greater Accra Region of Ghana. The effect of Practical Education Network (PEN)’s approach of training STEM teachers to employ hands-on activities using low-cost, locally-available resources was studied in terms of student learning outcomes, attitudes towards learning science, and interest in STEM majors/ careers. Over a 2.5-month period, the science teacher at each experimental school received a weekly training on a hands-on activity and lesson observation by the respective PEN Trainer. A survey on attitudes towards science and a previous edition of the national exam (BECE) were administered to all students before and after the intervention. The mean pre-post differences were compared between the experimental and control schools. The intervention caused an average of 10.9% increase in exam scores (difference-in-differences), but the results were mixed at the school-level. Unpaired t-tests and Hedge’s g tests were used to determine statistical significance between the two groups. Student engagement increased significantly (p = 3 x 10 -7 , g = 0.85), and student enjoyment of science increased 22% more, on average. The intervention disproportionately affected the females positively, enabling greater learning gains (14.5% vs. 5.3% for the males), greater increase in engagement, and a significant shift in interest towards STEM majors and careers, which their male counterparts did not experience. Results from this study should inform the design of future studies with longer duration and which account for factors such as school infrastructure quality.
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    Effect of particle size and sintering time on the mechanical properties of porous Ti–6Al–4V implant
    (Springer Nature, 2020-04) Azeez, Akeem A.; Danyuo, Yiporo; Obayemi, John. D.
    Titanium alloys have been extensively used in biomedical applications owing to its low density, excellent biocompatibility (i.e., biological and chemical inertness), and unique mechanical properties. However, there is a high disparity between Young’s moduli of the implant and the natural bone. This disparity causes stress shielding in the body. This paper presents the effect of particle size and sintering time of Ti–6Al–4V powder used in the formation of a porous implant, sintered at 980 °C. Morphological characteristics of the sintered samples were obtained with a scanning electron microscope. The effect of surface hydrophilicity of the samples was elucidated via surface wettability testing using contact angle measurement with bio-fluid. Mechanical characterization was also evaluated with nanoindentation and a universal testing machine. The relation between Young’s modulus and sintering time was presented. It was observed that the wettability decreases with sintering time and the Ti alloy powder with particle size < 150 µm had the Young’s modulus that is closer to the modulus of the bone; the optimum sintering time was 5 h.
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    Laser application of nanocomposite hydrogels on cancer cell viability
    (MRS Advances, 2020) Danyuo, Yiporo; Salifu, A. A.; Ani, C. J.; Dozie-Nwachukwu, S.; Ezenwafor, Theresa; Yirijor, J.
    Nanocomposite hydrogels of poly-n-isopropyl were prepared by incorporating gold and magnetite nanoparticles. The nanocomposite-based hydrogels formed were geometrical, ~7.3 mm in diameter and 5 mm thick (in the swollen state). Morphological analysis was characterized by a scanning electron microscope. Drug-loaded hydrogels were subjected to laser heating at 1 W, 1.5 W and 2 W for 20 min in each laser cycle. The metabolic activities of the cells were analysed. The photothermal conversion efficiency of the nanocomposite hydrogels was also evaluated for P(NIPA)-AuNP-PG and P(NIPA)-MNP-PG to be 36.93 and 32.57 %, respectively. The result was then discussed for potential applications whereby metalbased hydrogels can be employed in microfluidic devices for targeted cancer drug delivery.
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    Recycling of plastic waste materials: Mechanical properties and implications for road construction
    (MRS Advances, 2020) Panashe, Jennifer Alista; Danyuo, Yiporo
    This paper presents a recent study on recycling poly-ethylene-tetraphylate (PET), known as plastic waste material in Ghana, to wealth. Composites were produced by heating aggregates together with shredded PET plastic waste material, while bitumen was added to the plasticcoated aggregates. The composites produced were reinforced with 4.5 wt%, 9.0 wt%, 13.6 wt%, and 18.0 wt% PET. Mechanical properties of the fabricated composite samples were studied with a Universal testing machine for optimization. The work demonstrated that shredded PET plastic waste material acts as a strong binding agent for bitumen that can improve on the shelf life of the asphalt. From the results, 13.6 wt% concentration of PET was shown to experience the maximum compressive strength and flexural strength. Besides, water resistance was shown to increase with PET concentrations/weight fraction. From the data characterized 13.6 wt% of PET plastic gives the optimum plastic concentration that enhances the rheological properties of bitumen. The implications of the result are therefore discussed for the use of 13.6 wt% PET in road construction.
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    Development of a low-cost biomedical device to enhance pneumonia diagnosis in children
    (MRS Advances, 2020) Mhandu, Esau; Danyuo, Yiporo
    Pneumonia has contributed greatly to child mortality, especially among children under the ages of five in sub-Saharan Africa, killing more children than the number of children dying from HIV/AIDS. The current methods of diagnosing pneumonia involved physical examination and chest x-ray which are limited by low accuracy, high error margins, higher cost, and stands the risks of inducing cancer. In this work, a low-cost, non-invasive biomedical device was designed and developed to improve accuracy in diagnosing pneumonia. The device functions to detect fluid in a lung consolidated by pneumonia. Dry grouting sponge was used as a phantom for a healthy lung, while a wet sponge was used to mimic a pneumoniaconsolidated lung. Surface exciter was used to produce sound waves which travelled through one side of the phantom and are detected on the other end using an electronic stethoscope. The signals detected were digitally analyzed using MATLAB and AUDACITY software. The differences in resonant frequencies from the power spectrum analysis of sound waves as they travelled through the sponges were used to distinguish between a pneumonia-consolidated lung and a healthy lung.
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    Mechanical characterization of earth-based composites materials reinforced with treated bamboo fibres for affordable housing
    (MRS Advances, 2020) Asare, Benjamin Jnr; Danyuo, Yiporo
    This paper presents the characterization of laterite-cement-based matrix composites, reinforced with chemically modified bamboo fibers. Fiber extraction and chemical modification were first explored by soaking slabs of bamboos in NaOH solution (5 wt.% of NaOH in distilled water) for 14 days. Fiber characterization, as well as the flexural and compressive strength of reinforced composites, were carried out with MTS universal mechanical testing machine. Comparative results on the compressive and flexural strength were obtained at 80 wt.% laterite (L) to 20 wt.% cement (C) with fiber ratios from 5-25 wt%. The compressive strength of the composites varied from 7.2 MPa (at 5 wt.% bamboo fiber) to 17.67 MPa (at 25 wt% fiber blocks). The hardness of the composites was found to improve from 66.67-75.0 HD with bamboo fibers. Results were then discussed for possible structural applications such as enhancing low-cost building blocks for rural communities in Ghana.
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    Event-B and Cloud Provers
    (Final publisher: University of Birmingham, 2015-04) Iliasov, Alexei; Stankaitis, Paulius; Adjepon-Yamoah, David Ebo
    We discuss the whys and hows of remotely managing a collection of automated theorem provers supporting verification of Event-B models in the Rodin Platform[5]. We report on the current state of the work, our general aspirations and a range of technical obstacles encountered so far.
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    Rodin Platform Why3 plug-in
    (Springer, Cham, 2016-05) Iliasov, Alexei; Stankaitis, Paulius; Adjepon-Yamoah, David; Romanovsky, Alexander; Note: David Adjepon-Yamoah is a lecturer in Computer Science & Information Systems at Ashesi University
    We briefly present the motivation, architecture and usage experience as well as proof statistics for a new Rodin Platform proof back-end based on the Why3 umbrella prover. Why3 offers a simple and versatile notation as a common interface to a large number of automated provers including all the leading SMT-LIB and TPTP compliant tools. The plug-in can function either in a local mode when all the provers are installed locally, or remotely as a cloud service. We discuss the experience of building the tool, the current status and the potential advantages of a cloud-hosted proof infrastructure.
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    Using OLPC laptop technology as a computer science case study teaching tool
    (Consortium for Computing Sciences in Colleges, USA, 2009-04) Buchele, Suzanne Fox
    The One Laptop Per Child project has succeeded in developing a novel computer that is tailored to the particular needs of the developing world. The use of this example of a modern computer systems design challenge can be a valuable case study as a teaching tool in computer science. The OLPC laptop is a multiple-purpose computer that is rugged, low-cost, low-power, mesh- networked, and inexpensive. An overview of the technology in the laptops is given, as well as curricula suggestions for using the laptops in an undergraduate computer science curriculum.