Development and Characterization of Acrylic Based Bone Cements

Bone tissue engineering has emerged as a multidisciplinary field in recent times with an aim to expedite the process of regeneration of damaged or diseased tissues. This study is an attempt to fabricate and characterize Tricalcium Phosphate (TCP) and Chitosan incorporated Polymethylmethacrylate (PMMA) based bone cement. In total two experimental PMMA based bone cements were fabricated that were differentiated by presence and absence of Chitosan. In both groups (10 and 30 wt.%) TCP were incorporated into Methyl methacrylate (MMA) monomer. PMMA was used as a control. The physical, mechanical and thermal properties of the composites were assessed. Morphological changes of PMMA after the introduction of TCP and Chitosan were observed by means of X-ray diffraction (XRD). Major peak shifts in Fourier transform Infrared spectroscopy (FTIR) spectra demonstrated the strong bonding of PMMA with incorporated materials. PMMA incorporated with 10% TCP showed the maximum wettability in absence of Chitosan. Hardness of the tested specimens decreased with increasing content of TCP which in turns enhanced ductility. It was also observed that neither of the samples showed significant degradation. The incorporation of additives enhance the physical and chemical properties of PMMA as bone cement.

Synthesis, UV-Vis Spectroscopic and Physico-chemical Characterization of Oxovanadyl Complexes of Lincomycin and Neomycin

In the recent past, the pharmaceutical modification of drug molecules by complexation with biologically relevant metals to improve their properties such as stability, dissolution rate, absorption and bioavailability has been extensively studied. In order to achieve better and enhanced medicinal activity, vanadyl complexes of the widely used lincomycin (Lin-van) and neomycin (Neo-van) have been synthesized and their physico-chemical properties examined. The UV-Vis absorption properties of these complexes were determined and their antimicrobial activities were tested against some pathogenic organisms viz: Proteus vulgaris, Klebsiella pneumonae, Escherichia coli and Staphylococcus aureus. In all cases, Neo-van showed better antimicrobial activity than Lin-van while both complexes showed better activity than the antibiotic lincomycin and the previously reported Cu-Lin. Keywords: lincomycin, neomycin, UV-Vis spectroscopy, Physico-chemical, Oxovanadyl, synthesis

Interactions between RAP and virgin asphalt binders in field, plant, and lab mixes

Reclaimed asphalt pavement (RAP) has been used in asphalt mixes for several years in the United States. However, the interactions between the RAP binder and the virgin asphalt binder (VAB) need further investigations. Thus, the main objective of this study was to explore the rheological and chemical properties of extracted asphalt binders (EABs) from plant, field, and lab mixes. The plant mixes were collected from behind the paver, reheated to the compaction temperature, and compacted in the lab. The field mixes were collected as cores within two weeks after the end of the construction process. The lab mixes were fabricated in the lab using the same materials used in the plant and field mixes. The mixes contained high asphalt binder replacement percentages by RAP, which were greater than 30%. The EABs were treated as rolling thin film oven aged VABs (RTFO AVABs). The rheological properties of EABs and RTFO AVABs were analyzed using temperature sweep, frequency sweep, and multiple stress creep recovery tests. Chemical investigations of EABs and RTFO AVABs were carried out using Fourier transform infrared spectroscopy and thermogravimetric analysis. The EABs from plant or lab mixes showed higher stiffnesses than EABs from field mixes. This occurred because of the extra heating that was implemented for the plant mixes before the compaction in the lab, which caused more interactions between the RAP binder and VABs. The fabrication mechanism, mixing and short-term aging processes, used in lab mixes caused more interactions between RAP binder and VABs than in the field mixes.

Effect of pH on Soil Chemical Properties and Maize Performance in Abakaliki, Nigeria

Background: Low soil productivity in Nigeria and Africa sub sahara is considered as one of the major causes of food insecurity and under nutrition. This area is considered among the most regions affected by acidity on soil nutrients optimization. Despite of its severity, there is limited knowledge about limiting effect of pH on nutrients availability and maize yield in the state. Evolving a technology that does not depend on traditional system of amendment for pH assessment for increased soil productivity must first of all go through a good knowledge of the nature and distribution of soil studied. The present study aimed to evaluate three pH (4, 7 and 9) values on soil chemical properties in the state and assess maize performance under these conditions in order to control and manage pH related problems. Methods: In the field-laboratory investigation during 2018-2019 at different localities of Ebonyi State were surveyed. Three sampling localities were selected based on geographical situation, climate and local condition. In the laboratory, the soil samples of natural stock collected were processed for mean pH values and confirmed with pH meter using standard laboratory method. Maize was used as test crop to assess effect of pH on its performance. Result: Our investigations in Ebonyi State have allowed us to inventory three pH values. Among the inventoried pH values, some are regarded adverse for soil productivity. The implication of soil pH on nutrients availability and maize performance was discussed. The current work will be a complementary contribution of detailed study of effect of pH on soil productivity.