Podiatric interventions and phototherapy within the management of chronic diabetic foot Ulceration : a review to compare the average healing time

Abstract: Diabetic foot ulceration is a serious complication of Diabetes Mellitus and a most important risk factor for lower limb amputations. Diabetes is characterized by chronic hyperglycemia related to the resistance of target cells to the action of insulin; which leads to degenerative disorders caused by macroangiopathy, microangiopathy and neuropathy. These factors favor the occurrence of lower limb ulcers and so delay their healing. The slow healing rate of chronic diabetic foot ulceration has a negative impact on the patients’ quality of life. Thus there is a need for the development of new treatment modalities to improve healing rate and outcome of diabetic ulcerations..

Alkaline solidification of gold mine tailings for production of lightweight masonry blocks

Abstract: South Africa is the world’s largest gold resource. This is due to the substantial amount of gold that exists in the Witwatersrand Basin. The processing of gold leads to the production of gold mine tailings. Gold mine tailings are generated from mineral processing of gold ore through which gold is separated. Mine tailings are generally waste materials and are normally disposed of in slurry form in storages constructed on huge areas of land, these storage facilities are called tailings dams. This study was conducted to strengthen and stabilize gold mine tailings by alkaline activation to produce masonry blocks that can be used for building and construction as per minimum requirements for ASTM C34-13, C129-14a and South African standard (SANS227: 2007). The effect of variation of Solid to liquid (S/L) ratio, NaOH concentration and temperature on the UCS was investigated. This was achieved by treating the gold mine tailings with NaOH solution. The feasibility of using gold mine tailings to produce lightweight masonry blocks was studied by conducting unconfined Unconfined Compressive Strength (UCS) tests, SEM imaging, and XRF and XRF analysis. The alkaline activation of Gold Mine Tailings (AU MT) at a S/L ratio of 14.31% and 9 M concentration had higher UCS than those produced at 3 M and 6 M. Curing temperature is an important factor affecting alkaline activation and the UCS of masonry block. The UCS increases with the curing temperature up to a certain level and then decreases with the curing temperature. For the AU MT herein, the optimum curing temperature was found to be 80 °C with bulk density of 1578 kg/m3. The AU MT based masonry block meet ASTM standards they can be used for building and construction purposes such as the building of structural clay load bearing wall tiles of all C34-03 ASTM designation grades and building blocks of ASTM designation C6210, type NW (negligible weathering) with the minimum UCS of 10.3 MPa

Development of lightweight construction blocks by alkaline activation of BOF slag

Abstract: Large quantities of basic oxygen furnace (BOFS) are dumped in landfills of which the available land for land-filling of large quantities of waste is reducing all over the world. It is therefore im-portant to develop processes which beneficiates solid waste; BOF slag specifically. The present study attempts to investigate the potential to synthesize BOF slag based light weight construc-tion blocks. The effects of several factors on the UCS of BOF slag based light weight construc-tion blocks (LWCB) was also investigated. The test variables were molarities of sodium hydrox-ide (NaOH) (5 M, 10 M and 15 M); the solid to liquid ratio (20 %, 25 % and 30 %); the sodium silicate (Na2SiO3) to Na! OH ratio (0.5:1, 1:1, 1.5:1, 2:1, 2.5:1 and 3:1); the curing temperature (40°C, 80°C and 100°C). It was found that optimum synthesis conditions were 5M NaOH, 80°C and 1:1 Sodium Silicate: NaOH ratio. The LWCB composite met the minimum requirements for ASTM C34-13, C129-14a and South African standard (SANS227: 2007)

Synthesis of silver nanoparticles and investigating their antimicrobial effects

>Magister Scientiae - MScWater is essential for life, yet access to safe drinking water is still a major concern worldwide due to waterborne diseases. The current study proposes silver nanoparticles (AgNPs) as an antibacterial agent. Silver nanoparticles were synthesised using different reductants and stabilisers, and the resulting structures were characterised with Ultra-violet visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) analysis. The antibacterial properties of the AgNPs were tested against a panel of 5 indicator organisms: Cupriavidus metallidurans, Staphylococcus epidermidis, Mycobacterium smegmatis, Bacillus cereus and a multi-drug resistant Escherichia coli 1699. Spherical AgNPs that absorbed at around 400 nm, with diameters ranging between 18.8-26.4 nm or 5.4-13.1 nm were prepared by ascorbic acid or sodium borohydride respectively. The optimum processing conditions that produced 6±1.8 nm spherical nanoparticles included maintaining the temperature at 0 ⁰C, the pH at 9.78 and the NaBH4/Ag/PVP ratio at 16:1:10. Exposing AgNPs to light for 6 hours did not alter the particle size rather it changed the particles shape from spherical to icosahedral. Stirring caused particles to agglomerate, however, no agitation resulted in the formation of irregular structures of different sizes. Sensitivity to the AgNPs ranged between 25 % and 100 % reduced bacterial growth depending on the strains used and the concentration of the AgNPs. The Gram negative bacteria were more sensitive to AgNPs than Gram positive bacteria. However silver ions were more toxic than AgNPs for all but one of the strains tested, B. cereus was completely resistant to both Ag+ and AgNPs. C. metallidurans and E.coli (1699) showed a dose dependent sensitivity to AgNPs and the minimum inhibitory concentrations were established at 50 and 20 mg/L AgNPs respectively. C. metallidurans and E.coli (1699) were also eradicated by 10 mg/L Ag+. The E. coli TEM images showed accumulation of AgNPs within the cells, cell shrinking and leakage of cellular components. This suggests that AgNPs have a similar toxicity effect on bacterial cells as Ag+

Patterns and predictors of antimicrobial resistance among Staphylococcus spp. from canine clinical cases presented at a veterinary academic hospital in South Africa

Background Antimicrobial resistance in staphylococci, often associated with treatment failure, is increasingly reported in veterinary medicine. The aim of this study was to investigate patterns and predictors of antimicrobial resistance among Staphylococcus spp. isolates from canine samples submitted to the bacteriology laboratory at the University of Pretoria academic veterinary hospital between 2007 and 2012. Retrospective data of 334 Staphylococcus isolates were used to calculate the proportion of samples resistant to 15 antimicrobial agents. The Cochran-Armitage trend test was used to investigate temporal trends and logistic regression models were used to investigate predictors of antimicrobial resistance in Staphylococcus aureus and Staphylococcus pseudintermedius. Results Results show that 98.2% (55/56) of the S. aureus isolates were resistant to at least one drug while 42.9% were multidrug resistant. Seventy-seven percent (214/278) of the S. pseudintermedius isolates were resistant to at least one drug and 25.9% (72/278) were multidrug resistant. Resistance to lincospectin was more common among S. aureus(64.3%) than S. pseudintermedius (38.9%). Similarly, resistance to clindamycin was higher in S. aureus (51.8%) than S. pseudintermedius (31.7%) isolates. There was a significant (p = 0.005) increase in S. aureus resistance to enrofloxacin over the study period. Similarly, S. pseudintermedius exhibited significant increasing temporal trend in resistance to trimethoprim-sulphamethoxazole (p = 0.004), clindamycin (p = 0.022) and orbifloxacin (p = 0.042). However, there was a significant decreasing temporal trend in the proportion of isolates resistant to doxycycline (p = 0.041), tylosin (p = 0.008), kanamycin (p = 0.017) and amoxicillin/clavulanic acid (p = 0.032). Conclusions High levels of multidrug resistance and the increasing levels of resistance to sulphonamides, lincosamides and fluoroquinolones among Staphylococcus spp. isolates in this study are concerning. Future studies will need to investigate local drivers of antimicrobial resistance to better guide control efforts to address the problem

Kinetic study on the removal of iron from gold mine tailings by citric acid

Abstract: The Gold mining generates large volumes of tailings, with consequent disposal and environmental problems. Iron tends to react with sulphur to form pyrite and pyrrhotite which then react with rain water forming acid rain. The study focuses on the removal of iron (Fe) from Gold Mine tailings; Fe was leached using citric acid as a leaching reagent. Three parameters which have an effect on the removal of Fe from the gold mine tailings, namely; temperature (25 ºC and 50 ºC), reagent concentration (0.25 M, 0.5 M, 0.75 M and 1 M) and solid loading ratio (20 %, 30 % and 40 %) were investigated. It was found that the recovery of Fe from gold mine tailings increased with increasing temperature and reagent concentration, but decreased with increasing solid loading ratio. The optimum conditions for the recovery of Fe from gold mine tailings was found to be at a temperature of 50 ºC, reagent concentration of 1 M and solid loading of 20 %. Three linear kinetic models were investigated and Prout- Tompkins kinetic model was the best fit yielding linear graphs with the highest R2 values

Cement and fly ash stabilised gold mine tailings for the development of new material

Abstract: More than 500 gold tailings and a number of fly ash dumps exist in South Africa. These waste material contribute significantly to air, water and soil pollution. In this study gold mine tailings and fly ash which are readily available and result into environmental pollution were used to produce new building/construction material. The tailings were stabilised with cement and fly ash. Up to 20% of cement was incorporated in the mix design. The incorporation of 20% cement resulted into significant unconfined compressive strength (UCS) improvement of 3.89 MPa and 4.36 MPa at 56 and 90 days of curing, respectively. The strength development in fly ash and cement modified tailings was influenced by the pozzolanic and hydration reaction. The strength developed is applicable for the materials to be used for load bearing. The unconfined compressive strength of the developed specimen the composites met the minimum SANS 2001-CM1:2007 for hallow bricks to be used as masonry bricks

Enhancement of the geotechnical and geochemical properties of 1 gold tailings by BOF slag and class F fly ash

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Removal of manganese from solution using polyamide membrane

Abstract: The work demonstrates the performance of polyamide membrane in the removal of manganese ions from single salt aqueous solution simulating real acid mine drainage. The membrane was tested using a dead-end filtration cell with manganese sulphate was used to prepare a feed solution. The membrane flux and metal rejection was evaluated. Effect of operating parameters such as pH, initial feed concentration and pressure on membrane performance was investigated. The pressure was varied between 10 and 15 bar and it was observed that increasing the pressure increases the membrane flux. Acidic pH conditions contributed to the removal of the contaminate as Mn2+ ions are freely at low pH. The percentage rejection was found to be 63.5 to 77.6 % as concentration is increased from 290 ppm to 321 ppm for a feed solution. The membrane showed satisfactory results in removing metal ions from solution

Mechanical properties and structure of Fly ash modified Basic Oxygen Furnace Slag based geopolymer masonry blocks

Abstract: The objective of this research was to investigate the effect of Fly ash as a source of Si and Na on the mechanical performance of the Basic Oxygen Furnace Slag based (BOFS) geopolymer. BOFS has the lowest SiO2, Al2O3, Na2O content compared to other aluminosilicate sources (fly ash, metakaolin, granulated blast furnace slag and mine tailings); which have been used to effectively in geopolymer synthesis. SiO2 and Al2O3, contents of BOFS are respectively 5-7 times and 6-8 times lower than those of fly ash, metakaolin and granulated furnace slag (GBFS). This study evaluated the potential use of fly ash as a source of Si and Al to improve the mechanical performance of a BOFS based geopolymer. The influence of varying amount of Coal Fly Ash (FA) (10–50%) on UCS was studied. The effects of several factors on the UCS of BOFS geopolymer were also investigated. The test variables were molarities of sodium hydroxide (NaOH) (5 M, 10 M and 15 M); the solid to liquid ratio (20 %, 25 % and 30 %); and the curing temperature (20°C, 40°C, 80°C and 100°C). It was established that most favorable conditions for the geopolymer synthesis were FA was 10% of the mixture, 5M NaOH and 80°C curing temperature. Attempts has been made to relate the microstructure of BOFS/FA based composite with properties of geopolymer. Aggregation was identified as the main particulate process as established by the evolution of the particle size distribution (PSD) and its derived moments during the geopolymerisation process. The morphology of the particles appeared flaky and fluffy. The developed composite met the minimum requirement of ASTM C34-13 for a structural clay load bearing non exposed masonry and load bearing exposed side construction masonry