Analysis of the interaction between recombinant human Beta2 integrin I-domains and CD23
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
Characterization of chromatic dispersion in single mode fibre
- Authors: Wassin, Shukree
- Date: 2014
- Subjects: Fiber optics Electromagnetic waves , Electromagnetic waves -- Transmission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47807 , vital:40379
- Description: In this dissertation, an investigation of chromatic dispersion is presented. The Pulse delay and phase Shift chromatic dispersion characterization techniques were used for conducting the measurements. The experiments were performed in a modern optical fibre research laboratory and chromatic dispersion measurements were carried out on several lengths of G.652 and G.655 single mode fibres. The pulse delay characterization technique measures the time of flight between two modulated optical signals whilst propagating along the fibre under test. During phase shift experiments, the group delay is obtained by measuring the relative phase difference as a function of wavelength, between adjacent sinusoidal light signals. The pulse delay and phase shift characterization techniques illustrated excellent agreement in the measured! chromatic Dispersion coefficients along the G.652 standard single mode! fibre as well as the G.655 positive and negative non-zero dispersion shifted fibre. It was found that the measurement accuracy improved as the fibre length increased. A periodic shift between the modulated optical signals, propagating along the fibre was experimentally observed. It is to be remarked that the longer wavelength signals propagated faster along the G.655 positive non-zero dispersion shifted fibre in comparison to its transmission within the G.655 negative non-zero dispersion shifted fibre. Furthermore, it was found that the sinusoidal signal shifted towards the left along the G.655 negative NZDSF fibre whilst the shift occurred towards the right along the G.655 positive NZDSF fibre. Generally, the shift arising along the G.655 fibres was found to be smaller than the shift seen throughout the G.652 fibres. Towards the end of this study, a chromatic dispersion compensation system was designed and tested. Once characterization of the compensation link was completed, it was experimentally illustrated that the chromatic dispersion across the system was successfully reduced. Finally, a sum of squares of error statistical test showed that the phase shift technique is more accurate in comparison to the pulse delay method. This result was found to be in good agreement with published work found in literature.
- Full Text:
- Date Issued: 2014
- Authors: Wassin, Shukree
- Date: 2014
- Subjects: Fiber optics Electromagnetic waves , Electromagnetic waves -- Transmission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47807 , vital:40379
- Description: In this dissertation, an investigation of chromatic dispersion is presented. The Pulse delay and phase Shift chromatic dispersion characterization techniques were used for conducting the measurements. The experiments were performed in a modern optical fibre research laboratory and chromatic dispersion measurements were carried out on several lengths of G.652 and G.655 single mode fibres. The pulse delay characterization technique measures the time of flight between two modulated optical signals whilst propagating along the fibre under test. During phase shift experiments, the group delay is obtained by measuring the relative phase difference as a function of wavelength, between adjacent sinusoidal light signals. The pulse delay and phase shift characterization techniques illustrated excellent agreement in the measured! chromatic Dispersion coefficients along the G.652 standard single mode! fibre as well as the G.655 positive and negative non-zero dispersion shifted fibre. It was found that the measurement accuracy improved as the fibre length increased. A periodic shift between the modulated optical signals, propagating along the fibre was experimentally observed. It is to be remarked that the longer wavelength signals propagated faster along the G.655 positive non-zero dispersion shifted fibre in comparison to its transmission within the G.655 negative non-zero dispersion shifted fibre. Furthermore, it was found that the sinusoidal signal shifted towards the left along the G.655 negative NZDSF fibre whilst the shift occurred towards the right along the G.655 positive NZDSF fibre. Generally, the shift arising along the G.655 fibres was found to be smaller than the shift seen throughout the G.652 fibres. Towards the end of this study, a chromatic dispersion compensation system was designed and tested. Once characterization of the compensation link was completed, it was experimentally illustrated that the chromatic dispersion across the system was successfully reduced. Finally, a sum of squares of error statistical test showed that the phase shift technique is more accurate in comparison to the pulse delay method. This result was found to be in good agreement with published work found in literature.
- Full Text:
- Date Issued: 2014
Remuneration and rewards strategies at the Nelson Mandela Metropolitan University
- Authors: Bobi, Lungiswa
- Date: 2011
- Subjects: Nelson Mandela Metropolitan University , Compensation management -- South Africa , Employee retention -- South Africa -- Port Elizabeth , Incentives in industry , Employee motivation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:9393 , http://hdl.handle.net/10948/d1021232
- Description: To be competitive, organisations need to ensure that all their resources are functioning at optimal level. The most important of these resources being its employees. This is because their commitment can guarantee the attainment of organisational goals. Commitment can be attained by an organisation through the payment of internally and externally competitive remuneration and reward packages, that communicate the value of the employees to the organisation. Remuneration and reward strategies are a critical tool for organisations, as they can motivate, attract and retain high performing employees. The theories of motivation, such as, the equity theory, state that employees compare their compensation with that of others and that if they perceive inequity, can be de-motivated or leave an organisation. Therefore, it is imperative for an organisation to ensure that its remuneration and reward strategy is aligned with its business strategy, to ensure clear communication of goals. In order to prevent labour turnover and to ensure commitment and retention, the employer needs to offer total rewards, which include base pay, benefits, variable performance pay, recognition and an enabling work environment. These can be effective as they meet all employee needs as in Maslow‟s hierarchy of needs and ensure the satisfaction of the organisation‟s need for goal attainment. To gain more insight, an empirical study was conducted at the Nelson Mandela Metropolitan University. The results of the survey indicated that the NMMU‟s remuneration and reward strategy contained certain elements of the total rewards strategy. These are variable pay in the form of a service bonus and benefits plus based pay. This strategy seems to be ineffective to motivate and retain employees due to lack of clear communication and recognition. To motivate and retain its employees, the NMMU should improve its communication and engage employees and unions in defining remuneration and reward strategies through collaboration.
- Full Text:
- Date Issued: 2011
- Authors: Bobi, Lungiswa
- Date: 2011
- Subjects: Nelson Mandela Metropolitan University , Compensation management -- South Africa , Employee retention -- South Africa -- Port Elizabeth , Incentives in industry , Employee motivation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:9393 , http://hdl.handle.net/10948/d1021232
- Description: To be competitive, organisations need to ensure that all their resources are functioning at optimal level. The most important of these resources being its employees. This is because their commitment can guarantee the attainment of organisational goals. Commitment can be attained by an organisation through the payment of internally and externally competitive remuneration and reward packages, that communicate the value of the employees to the organisation. Remuneration and reward strategies are a critical tool for organisations, as they can motivate, attract and retain high performing employees. The theories of motivation, such as, the equity theory, state that employees compare their compensation with that of others and that if they perceive inequity, can be de-motivated or leave an organisation. Therefore, it is imperative for an organisation to ensure that its remuneration and reward strategy is aligned with its business strategy, to ensure clear communication of goals. In order to prevent labour turnover and to ensure commitment and retention, the employer needs to offer total rewards, which include base pay, benefits, variable performance pay, recognition and an enabling work environment. These can be effective as they meet all employee needs as in Maslow‟s hierarchy of needs and ensure the satisfaction of the organisation‟s need for goal attainment. To gain more insight, an empirical study was conducted at the Nelson Mandela Metropolitan University. The results of the survey indicated that the NMMU‟s remuneration and reward strategy contained certain elements of the total rewards strategy. These are variable pay in the form of a service bonus and benefits plus based pay. This strategy seems to be ineffective to motivate and retain employees due to lack of clear communication and recognition. To motivate and retain its employees, the NMMU should improve its communication and engage employees and unions in defining remuneration and reward strategies through collaboration.
- Full Text:
- Date Issued: 2011
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