Browsing by Author "Van Niekerk, Marthinus Gerhardus Mynhardt"

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    Moral Problems associated with Pediatric Deafness
    (Stellenbosch : Stellenbosch University, 2020-12) Van Niekerk, Marthinus Gerhardus Mynhardt; Van Niekerk, Anton A.; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Philosophy: Centre of Applied Ethics.
    ENGLISH ABSTRACT: Deafness in an adult is detrimental to communication and is therefore uncomfortable and debilitating not only for the deaf person, but also for those interacting with him/her. By contrast, for a child younger than 3 years of age, deafness has a profound effect on his/her global neurological development which,later in life,may lead to social isolation,poor self-image, learning problems with reduced academic achievement and eventually limited vocational choices. If the deafness is not diagnosed and treated promptly, the child will suffer its consequences for the rest of his/her life. Congenital, severe and profoundly deaf children can be successfully rehabilitated with Cochlear Implants,only if the diagnosis of deafness is made early, preferably before 6 months of age.Early diagnosis of deafness in a child is therefore imperative.Newborn Hearing Screening (NHS) can identify those newborn babies with a possible congenital deafness and enables the parents of such a child to confirm the diagnosis with additional tests before the child is three months old. NHS is a painless procedure with a low probability of harm. Non-diagnosis and not treating a baby with congenital deafness has a high probability of severe harm to both baby and parents, as well as the extended family.Quality of life for both the baby and the parents will be negatively affected if the congenital deafness is diagnosed and treated only later in the child’s life.Therefore, we may have a moral obligation to do universal NHS, i.e. screen all newborn babies for possible hearing loss.NHS assists the parents of a congenitally deaf child to have access to a CI for their child, when the child will benefit the most from the procedure, i.e. as soon after 6 months of age as possible. The availability and use of CIs are however viewed as a threat by the Deaf community. Deciding whether to have a CI for one’s child or letting the child become part of the Deaf culture is a moral dilemma that will be discussed. The moral issues surrounding the election for deafness in one’s future child and the effect CIs have on this situation, will also be discussed. Deafness in children is mostly caused by infectious diseases which can be prevented with vaccination. Vaccination is not only beneficial to the recipient, but also creates herd immunity that protects those children who cannot be vaccinated for medical reasons.Recently, especially in developed countries, there has been a trend towards not vaccinating one’s child, but the result is that relatively uncommon diseases, like measles,as well as their complications of deafness,are re-surfacing.Applying the Principle of Least Restrictive Alternative to an Intervention Ladder,it can be argued that compulsory or mandatory vaccination is necessary to keep the number of non-vaccinated children as small as possible and thus protect herd immunity. Everyone capable of being vaccinated, should do so, to compensate for those who cannot be vaccinated for medical reasons and can therefore not contribute to herd immunity. Compulsory vaccination may therefore also be morally justified by applying the Principle of Fairness.
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    Porous carbon nanofibers containing silica-coated iron oxide nanoparticles by carbonisation of electrospun amphiphilic copolymer nanocomposites
    (Stellenbosch : Stellenbosch University, 2019-03) Van Niekerk, Marthinus Gerhardus Mynhardt; Mallon, Peter; Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science.
    ENGLISH ABSTRACT: Amphiphilic PAN-g-PDMS copolymers were synthesized by conventional free radical polymerization of acrylonitrile monomer and PDMS macromonomer. Three chain lengths of PDMS macromonomer grafts were employed, each forming a series for which the monomer:macromonomer feed ratio was varied. SEC results showed a wide range of molar masses of the synthesized copolymers. This is to be expected given the uncontrolled nature of conventional free radical polymerization reactions. ¹H NMR measurements proved that a direct proportionality exists between the PDMS macromonomer feed and the incorporation thereof. Electrospinning of the synthesized PAN-g-PDMS copolymers from DMF was done at three different TCD’s. In some cases, the fiber diameters could be explained by considering the PDMS graft content in conjunction with the molar mass, though in many cases the reasons for patterns in fiber diameters could not be clarified. A possible reason for this is that the expected phase segregation was, to some extent, inhibited by the method of solution preparation that entailed stirring at 50 °C for an hour followed by sonication for an hour. It is noteworthy that copolymers containing 5 kDa PDMS grafts showed severe gelation of the polymer solution. DSC analysis performed on the as-synthesized powders as well as on the electrospun fibers revealed that the current samples do not follow any clear trends w.r.t. PDMS graft content. When considering the cyclization exotherm which is a necessary process in order to convert the precursor fibers into carbon fibers, an interesting observation was made for the three series of copolymers containing 5 kDa grafts: as the PDMS graft content is increased a shoulder forms which ultimately separates into a double peak in the thermogram. This is presumably due to severe phase separation of domains rich in PAN homopolymer and domains rich in PDMS grafts undergoing the cyclization reaction at different temperatures. Co-precipitation of IONPs yielded nanoparticles with a diameter of 10.2 ± 2.4 nm as determined by TEM analysis. Silica coating of the IONPs initially produced multi-core nanoparticles with a diameter of 62.6 ± 12.5 nm containing 72.2 wt.% silica determined gravimetrically. The amount of TEOS added as reagent was decreased in order to form single-core nanoparticles of 22.2 ± 4.3 nm containing 29.6 wt.% silica and thus a thinner shell thickness. Thermal pre-treatment of single-core nanoparticles at 800 °C produced nanoparticles that appear very similar to untreated single-core nanoparticles. Electrospun fiber-particle nanocomposites showed nanoparticle agglomeration in the case of multi-core nanoparticles and good dispersion in the case of single-core nanoparticles and thermally treated single-core nanoparticles. Fiber-particle nanocomposites containing thermally treated single-core particles electrospun after 18 h of solution ageing showed some particle agglomeration. Carbonisation of the fiber-particle nanocomposites containing thermally treated nanoparticles produced intact carbon fiber-particle nanocomposites that showed very little fiber breakage. Sorption capacity measurements revealed hydrophilic behavior which was substantiated by the presence of an absorption peak associated with silica in the ATR- FTIR spectrum of the carbon fiber membrane.