Synthesis, characterization and in vitro antibacterial analysis of carvacrol based-hybrid analogues
- Authors: Mbese, Zintle
- Date: 2019
- Subjects: Medicinal plants Herbs -- Therapeutic use
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14527 , vital:39998
- Description: he focus of this research was to synthesize and characterize carvacrol hybrid analogues. Twenty-one (21) carvacrol analogues were synthesized by reacting carvacrol with (1. 4- aminosalicylic acid, 2. ferrocene keto-butanoic acid, 3. Ferrocene butanoic acid, 4. succinic anhydride, 5. folic acid, 6. cinnamic acid, 7. leucovorin, 8. oleanolic acid, 9. artesunate, 10. cholesterol, 11. cholesterol succinate, 12. curcumin, 13. curcumin succinate, 14. zidovudine, 15. Zidovudine succinate, 16. 8-hydroxyquinoline, 17. 8-hydroxyquinoline succinate, 18. 2- (7-chloroquinolin-4-ylamino)ethyl 5-isopropyl-2-methylphenyl, 19. 2-(7-chloroquinolin-4- ylamino)ethyl 5-isopropyl-2-methylphenyl succinate, 20. 2-(2-(7-chloroquinolin-4- ylamino)ethoxy)ethyl 5-isopropyl-2-methylphenyl, 21. 2-(2-(7-chloroquinolin-4- ylamino)ethoxy)ethyl 5-isopropyl-2-methylphenyl succinate). The carvacrol analogues were characterized using FTIR, UHPLC-HRMS, 1H- and 13C-NMR spectroscopy. The antibacterial analysis was performed to evaluate the carvacrol analogues against bacterial strains. FTIR spectra of carvacrol analogues were found to exhibit peaks of C-O stretch and Ar-C in a range of 1014-1280 cm-1 and a range of 1414-1697 cm-1 which confirm the successful formation of esters. The proposed structures of carvacrol analogues were confirmed by the 1H- and 13C-NMR. The selected 1H-NMR signal for aromatic protons ranged at 6.00-8.95 ppm/δ. The selected 13C-NMR signal for ester carbon and aromatic carbons ranged at 160.0-175.0 ppm/δ and at 110.00-154.00 ppm/δ. The structures were also confirmed by UHPLC-HRMS. Carvacrol analogues exhibited the highest inhibitory effect against Gram-positive and Gram-negative tested bacterial strains.
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Exhaustible resources and the hotelling rule : an empirical test of the hotelling rule's significance to gold production in South Africa
- Authors: Mlambo, Courage
- Date: 2017
- Subjects: Natural resources -- Mathematical models Econometrics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4738 , vital:28507
- Description: The study sought to test the applicability of the Hotelling rule in South Africa. In environmental economics, the Hotelling rule has come to be a pillar of the exhaustible resources framework and in addition to this, it has presented essential insights into the consumption and extraction of non-renewable resources. Hotelling sought to address one important question which had been unanswered regarding the depletion of exhaustible resources: How much of the natural resource in question should be consumed presently and how much of it should be stocked up for future generations? The focus was to find a solution for those involved in the exploitation of natural resources to choose between the current value of the natural resource if extracted and sold and the future increased value of the asset if left unexploited. According to the Hotelling rule, the extraction path in competitive market economies will, under certain circumstances, be socially optimal. An extraction path that is not socially optimal compromises the welfare of future generations. The welfare of South Africa’s present population and more especially in the future will be greatly determined by the stock of natural resources available and the quality of the environment. Currently, the production processes deplete natural resources. Concern with the supposed increasing scarcity of gold in South Africa, and the possibility of running out of gold, has become a source of concern. South Africa’s gold reserves (gold in the ground that can be extracted profitably) are becoming depleted at an alarming rate. Most reserves are already exhausted; and the costs involved in mining lower-grade ore, and deposits located very deep in the ground, are becoming excessive. In light of this, this study sought to test the applicability of the Hotelling rule in South Africa. In order to empirically test the Hotelling rule, the study was guided by previous literature that had sought to test it. In this regard, the study used both descriptive and inferential statistics. The study has three data analysis chapters. The first two presented and examined the time series properties of gold prices, gold production and gold consumption. The third data analysis chapter examined the relationship between gold price and interest rates. In the first two data analysis chapters, visual inspection, growth rates, variance ratio tests and advanced unit root tests were used to examine the time series properties of gold prices, gold production and gold consumption. Results showed that the behaviour of the gold price series and gold production series in South Africa have a behaviour that is socially optimal. This is in line with the Hotelling rule. The rule predicts exponentially increasing resource prices and this result in mineral resources following the path of the positive trend. The positive trend is prompted by the increasing price reflecting the increasing scarcity of the resource. However, consumption trends were seen to be violating the Hotelling rule. The Hotelling rule predicts that the price increases until it eventually reaches the choke price, where the quantity demanded decreases to zero. However, in contrast to this, results showed that the demand for gold has been increasing instead of decreasing. This is not in line with the Hotelling rule. Furthermore the relationship between interest rate and gold price was negative and this suggested that the price of gold was not rising at the rate of the interest rate. The results of the study suggested that gold production is not following a social optimally path. The study recommended that the government come up with measures that prolong the lifespan of the gold reserves. These included research and development to promote technological innovations in the mining sector. This may make it possible for firms to access lower-grade ores. The study also recommended that since the Hotelling rule partly applied in the gold sector, there is a need to adopt some other theoretical measures that can ensure that the proceeds from the gold taxes are used in the most effective way.
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Impediments to the implementation of employee health and wellness policy : a study of Social Development - Eastern Cape, Amathole District
- Authors: Lutuli, Nondwe
- Date: 2017
- Subjects: Employee health promotion -- South Africa -- Eastern Cape Employee motivation -- South Africa -- Eastern Cape Health education|xGovernment policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/5473 , vital:29269
- Description: The White paper on Transforming Public Service Delivery no 1459 of 1997 stipulates that the wellbeing of employees needs to be accounted for. A directive to have employee health and wellness programmes established in all government departments was given by the director-general of the Department Public Service Administration in 2008. The Employee health and wellness programme is aimed at promoting and improving employee wellbeing, which is also linked to organizational wellness. The primary aim of the Employee Assistance Programme (EAP) is to make a positive contribution towards maximum employee productivity and effectiveness in the workplace. Employee health assessment conducted by the Department of Social Development in 2006 and 2009 confirmed that South African organizations, including the Department of Social Development, experience high levels of employee poor health. Studies suggest that both employees and the employers need to pay attention to the improvement of employee health and wellness. In 2012, an integrated employee health and wellness policy was developed to improve the Department of Social Development employee wellness. The interest to conduct the study emanates from the researcher‟s own supposition that the policy has not been fully implemented, this deduction is based on the fact that, although the policy has four critical focus areas, some of these areas, such as counselling, are not rendered. Literature reviewed includes the process of policy implementation and description of employee health and wellness, benefits of employee health and wellness programme for both employees and employer. A mixed method study was conducted to explore the implementation of the employee health and wellness policy as a strategy to improve both employee and organizational wellness within the Department of Social Development, Eastern Cape - Amathole District. The population of the study included both DSD management and non-managerial employees from Amathole District; the study also includes the Eastern Cape Department of Transport, Amathole District Municipality and South African Police Service (Mdantsane). Themes that were identified from qualitative data through semi- structured interviews by means of audio-recorder were triangulated through questionnaires and document analysis. Since the policy came into effect in 2012, results show that the implementation has been confronted with a number of challenges which include lack of support from the top management. Lack of buy in by DSD management has serious implications on the policy objectives; these include the inadequate distribution of capital, human and physical resources necessary to implement the policy. In order for the DSD to improve the implementation of employee health and wellness policy, the management needs to ensure that there is adequate provision of human and capital resources. Employees should be well-informed on policy guidelines and procedures and benefits to stimulate maximum utilisation. A decentralisation of implementation to Area offices is necessary to promote accessibility of services and prevent unnecessary delays in service delivery.
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Prevalence of Group B streptococcus and staphylococcus aureus colonization in the anogenital tract of pregnant women in the Eastern Cape Province, South Africa
- Authors: Stofile, P Z
- Date: 2017
- Subjects: Streptococcal infections Staphylococcus aureus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5983 , vital:29462
- Description: Neonatal sickness and death is increasingly becoming a public health problem worldwide. The colonization of Group B Streptococcus and Staphylococcus in the rectovaginal area is among the sources of infections in neonates which can result in illness and mortality. The over exposure of humans to antibiotics is the possible cause of resistance in bacteria. These resistant strains can be passed onto offspring, leading to resistant infections and increasing the morbidity of neonates because of treatment failures. Many people, including healthcare personnel are not aware of the effect of these bacteria, and informing clinics and hospitals can help create awareness and monitoring the levels of resistance among bacteria can assist in preventing the transference of the bacteria. In this study we investigated the prevalence of group B Streptococcus (GBS) and Staphylococcus aureus in the anogenital tract of pregnant women in the Eastern Cape Province, South Africa. A total of 49 isolates from 25 (30.5 percent) pregnant women colonized with GBS were isolated from vaginal and rectal swabs of 82 pregnant women at 25-37 gestation who participated in this study. These isolates were obtained using standard microbiological methods and confirmed by polymerase chain reaction (PCR) technique aimed at the ScpB gene. The isolates were further screened for the presence of 9 serogroups (Ia, Ib, II, III, IV, V, VI, VII, VII) and serogroups Ib 2 (4.8 percent), II 20 (40.8 percent) and IV 5 (10.2 percent) and 22 non-typable (44.9 percent) were identified. Susceptibility profiling of the isolates to 12 antibiotics (tetracycline, clindamycin, erythromycin, gentamycin, naladixic acid, norfloxacin, chloramphenicol, cefuroxime, cefotaxime, imipenem, penicillin and vancomycin) was tested in vitro by the standardized disc diffusion method. All the confirmed GBS isolates (49) were resistant to erythromycin, tetracycline and clindamycin. A higher percentage of the isolates were resistant to gentamycin 44 (90 percent), nalidixic acid 41 (84 percent), penicillin 41 (84 percent), chloramphenicol 38 (78 percent), cefuroxime 36 (74 percent), imipenem 36 (74 percent), cefotaxime 35 (71 percent), norfloxacin 32 (65 percent) and vancomycin 31 (78 percent). Multiple antimicrobial resistance patterns ranged from 9‒11 and indices ranged from 0.7‒0.9, respectively. Among the antimicrobial resistance determinants examined, genes encoding for resistance to erythromycin ermB 25 (51 percent), tetracycline tetM 32 (65 percent) and penicillin bla-Z 4 (8 percent) only were identified. On the other hand, screening for S. aureus yielded a total of 7 isolates from 4 study participants as confirmed by PCR based on staphylococcal, nuc gene. The isolates were further screened for the presence of six virulence genes (Hla, Hlb, LUKM, LUKED, PVL, Eta and Etb) and antibiotic susceptibility pattern by the disc diffusion method using 12 (penicillin, vancomycin, tetracycline, rifampicin, imipenem, gentamycin, chloramphenicol, norfloxacin, oxacillin, erythromycin and sulfamethoxazole-trimethoprim) antibiotics that are adopted in the treatment of infections caused by the organism. PVL 6 (85.7 percent) and eta 1 (14.3 percent) were the two virulence genes detected. The following percentages of antibiotics resistance among the isolates were observed; penicillin G 7 (100 percent), clindamycin 7 (100 percent), vancomycin 5 (100 percent), rifampicin 5 (71 percent), oxacillin 5 (71 percent), erythromycin 5 (71 percent) gentamycin 3 (43 percent), norfloxacin 3 (43 percent), sulfamethoxazole-trimethoprim 3 (43 percent), chloramphenicol 2 (29 percent), imipenem 1 (14 percent). Multiple antimicrobial resistance patterns ranged from 7‒8 and indices ranged from 0.6‒0.7, respectively. Genetic profiling of the resistance genes identified erythromycin ermB 5(71.4 percent), tetracycline tetM 5(71.4 percent) and penicillin bla-Z 1(14.3 percent) only. The findings from the study have revealed GBS and S. aureus colonization of pregnant women in the Eastern Cape Province, and these have great public health implications especially for the neonates who are mostly likely to be infected during birth. The unidentifiable multidrug resistant serogroups of GBS as well as resistant S. aureus limit the choice of drugs in the management of infections caused by these pathogens more so if transmitted to infants. Therefore asymptomatic pregnant women needed to be properly educated about the bacteria as well as the precautions that need to be taken.
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Quality indices of the Nahoon beach and canal in Buffalo City Metropolitan Municipality, Eastern Cape, South Africa
- Authors: Ebomah, Kingsley Ehi
- Date: 2017
- Subjects: Pathogenic bacteria -- South Africa -- Eastern Cape Water quality -- South Africa -- Eastern Cape -- Measurement Water -- Microbiology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8122 , vital:31525
- Description: Faecal indicator bacteria have long been recommended for usage in water quality monitoring of various water sources including surface water. A large number of people in different parts of the world often engage in recreational and other commercial activities at the various beaches along the coastal lines, most especially, during summer season and festive periods. It is generally assumed that beach water is safe all the times, however, there have been increasing reports of beach and other coastal water pollutions because of rising anthropogenic activities around coastal areas globally. The presence of pathogens in faecal contaminated beach water either directly or indirectly increases the risk of human exposure which may result in skin infections as well as the ingestion and transmission of multidrug resistant pathogens. Microorganisms may gain entry into beach water directly from improperly treated final effluents released by wastewater treatment plants and from agricultural runoffs and/or faulty drainages. The aim of this study was to evaluate the quality indices of the Nahoon Beach and canal waters in the Eastern Cape Province of South Africa. In order to achieve this aim, the objectives of this study were as follow: to determine the seasonal variations of the physicochemical characteristics of the Nahoon beach and canal waters, to assess the microbiological quality of the beach water by assessing the prevalence of potentially E. coli and Enterococcus species, and to evaluate the antibiogram profile of the E. coli pathotypes and Enterococci species recovered from the beach water samples. Water samples were collected bi-weekly for a period of twelve months, during which on-site physicochemical analyses were carried out. Bacteriological assessment was performed using the membrane filtration technique and the necessary incubation conditions were followed. Identification of the target organisms was done by molecular based methods using PCR (polymerase chain reaction) while antibiotic susceptibility testing was done using the disk diffusion method. During the spring season (August to October) and periods of festive activities (December, January and March), it was observed that turbidity was at its highest, consequently, influencing total dissolved solids and a rise in the values of pH and electrical conductivity. Microbiological qualities assessed follow the order: Escherichia coli (101 – 103 CFU/100ml) and Enterococcus (101 – 102 CFU/100 ml). The results show that 41.2percent (107/260) of the presumptive E. coli isolates were positive for uidA gene. A total of 73 out of 107 (68.2percent) PCR-confirmed E. coli isolates were observed to belong to different pathotypes while 59percent (102/172) of the presumptive Enterococcus strains isolated were positive for SodA gene (Enterococcus spp.). Out of 102 enterococci isolates, 45 strains were identified as species (E. faecalis and E. faecium) and these were subjected to antibiotic susceptibility testing. The E. coli strains exhibited a frequency of 100percent resistance against ampicillin while the Enterococcus strains also showed 100percent resistance against vancomycin and linezolid. Target genes eae 11 (10.3percent); ipaH 14 (13.1percent); ibeA 48 (44.9percent) that encode pathogenicity in E. coli were successfully amplified by PCR suggesting that the isolates are potentially pathogenic strains whereas Enterococcus spp. including Enterococcus faecalis 26 (25.5percent) and Enterococcus faecium 19 (18.6percent) were also identified in the water samples. In this study, the phenotypic antibiogram profiles of the E. coli isolates revealed that all 73 (100percent) of the pathotypes were resistant to ampicillin, 67 (91.8percent) were resistant to amikacin, gentamicin and ceftazidime while about 61 (83.6percent) and 51 (69.9percent) were resistant to tetracycline and ciprofloxacin as well as trimethoprim respectively. About 21.9percent (16) of the E. coli isolates exhibited multiple antibiotic resistances with 100percent being resistant to eight antibiotics whereas multiple antimicrobial resistances were observed in 14 (31percent) of the enterococci strains and the most predominant profile was the simultaneous resistance to ampicillin, penicillin and vancomycin. The results obtained in this study show that the beach water generally did not comply with the set guidelines. The results also suggest the possible survival and prevalence of potentially virulent E. coli as well as Enterococcus strains in the aquatic environment which may be a cause of concern for public health. Monitoring of the quality of surface water and antimicrobial resistance (AMR) in bacteria is of great importance and has clinical and human health significance. Nonetheless, this study underscores the need for more detailed study of other waterborne pathogens of health importance including enteric viruses to ascertain the safety of the beach for human use.
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Synthesis and structural studies of NiS and PdS nanoparticles/nanocomposites from dithiocarbamates single source precursors
- Authors: Nqombolo, Azile
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11359 , http://hdl.handle.net/10353/d1021326
- Description: The main aim of this research is to synthesize Ni(II) and Pd(II) dithiocarbamate complexes and use them as single source precursors for the synthesis of NiS and PdS nanoparticles and metal sulphides potato starch nanocomposites. Four dithiocarbamate ligands were synthesized and characterized using elemental analysis and spectroscopic techniques. The ligands were used to prepared homoleptic Ni(II) and Pd(II) complexes of the dithiocarbamate ligands. The metal complexes were characterized with elemental analysis, UV-Vis, FTIR and 1H-NMR spectroscopic techniques. Conductivity measurements indicate that all the complexes are non-electrolytes in solution and results from the electronic spectra studies confirmed the proposed 4-coordinate square planar geometry around the metal ions. The nickel complexes showed d-d transitions around 477 nm while in the palladium complexes, no d-d transitions were observed but the compounds showed strong metal to ligand charge transfer transitions. From the FTIR spectra studies, it can be confirmed that the complexes were successfully synthesised because all peaks of interest were observed at expected regions from the literature. The νC-N was observed around 1469-1495 cm-1, νC=S around 1101-1188 cm-1 and νC-S around 738-1060 cm-1 for both Ni(II) and Pd(II) complexes. νNi-S was observed around 375-543 cm-1 and νPd-S around 529-545 cm-1. The FTIR also confirmed that the dithiocarbamate ligands act as bidentate chelating ligands through the sulfur atoms. The complexes were used as single source precursors and thermolysed in hexadecylamine (HDA) at 220 °C to prepare four HDA-capped nickel sulfide nanoparticles and four palladium sulfide nanoparticles. The as-prepared nanoparticles were studied with optical absorption spectra, photoluminescence, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The optical studies results showed that NiS have large band gaps that are greater than that of the bulk, therefore they are found to be blue shifted relative to the bulk, which shows that they have small particle size and thus confirming their quantum confinement effect. PL spectra reveal that the emission peaks are red shifted compared to the absorption band edges of the nanoparticles. The XRD patterns confirmed the formation of cubic and rhombohedral phase for NiS nanoparticles and cubic phase for PdS nanoparticles. SEM images of both NiS and PdS show uniform surface morphology at low and high magnification with different shapes. EDS analyses confirmed the presence of Ni, S, and Pd in each of the spectrum indicating that the nanoparticles were successfully synthesized. TEM images showed that the synthesised nanoparticles have uniform and narrow size distribution with no agglomeration. The sizes of the NiS nanoparticles were found to be in the range of 12-38 nm for NiS1, 8-11 nm for NiS2, 9-16 nm for NiS3 and 4-9 nm for NiS4. The TEM images for the as-prepared PdS nanoparticles showed that the average crystallite sizes are 6.94-9.62 nm for PdS1, 8-11 nm for PdS2, 9-16 nm for PdS3 and 4-9 nm for PdS4 respectively. The nanoparticles were used to prepare potato starch nanocomposites and SEM images indicate that the surface morphology of starch polymer nanocomposites compose of potato starch and few particles in between the pores of the matrix, this is due to the small ratio of nanoparticles used.
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