1,721,005 research outputs found
Epidemiological and laboratory investigations of the hazardous effects of wine on human enamel
No full textThesis (PhD)--Stellenbosch University, 2005ENGLISH ABSTRACT: The purpose of this study was to investigate the erosive effect of wine on human permanent teeth.
A multidimensional research approach utilising epidemiological investigations, Microhardness tests, Scanning Electron Microscopy and Confocal Laser Scanning Electron Microscopy (CLSM) were employed. The combination of these three scientific methods enabled the researcher to arrive at new concepts about the physical characteristics of the influence wine has on the
dentition with special reference to enamel.
A difference in erosion between teeth of wine-makers (and/or wine-tasters) and those who are not wine-makers, was clearly demonstrated. It is, however, possible that this difference might partially be attributed to the fact that the two main comparative groups were of opposite genders. In comparative epidemiological studies the design is constructed to have the groups similar with
respect to background aetiology and different only to the factor under investigation, in this instance the frequent exposure to wine (high frequency and long duration of contact between wine and the teeth). In all likelihood the continuous, frequent exposure of wine-makers to wine is the major factor in the differences obtained (e.g. tooth surface loss and dentition status) in this study. A strong positive relationship was noted between statistically weighted tooth surface loss and the chronological age of wine-makers. A similar positive relationship could not be demonstrated in the case of years employed in the wine industry and tooth surface loss.
All the Microhardness tests and microscopic investigations conducted confirmed the deleterious influence of wine on enamel. A clear 'dose-response' relationship was demonstrated by means of the Microhardness tests. The Scanning Electron Microscope and the Confocal Scanning Laser Electron Microscope (CLSM) work both corroborated the effects determined by the Microhardness tests. Differences were also demonstrated in the surface morphology of enamel with respect to the exposure to the wines investigated in the Scanning Electron Microscope (SEM) (three wines) and CLSM (two wines) studies. Differences with respect to severity were well established by means of the SEM investigations. Surface and subsurface lesions were observed with the aid of CLSM on the enamel exposed to the two wines.AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om ondersoek in te stel na die effek van wyn op permanente tande by mense. 'n Multidimensionele benadering is gevolg waarin epidemiologiese ondersoeke, mikro-hardheid toetse, skandering elektronmikroskopie en konfokale laserskandering elektronmikroskopie gebruik is. Die kombinasie van hierdie drie wetenskaplike metodes stel die navorser in staat om nuwe konsepte te vorm ten opsigte van die eienskappe rondom die invloed van wyn op tande, met spesiale verwysing na glasuur.
'n Verskil in die erosie van glasuur tussen die tande van die wynmakers (wynproewers) en niewynmakers, is duidelik aangetoon. Dit is egter moontlik dat die verskil gedeeltelik toegeskryf kan word aan die feit dat die twee hoofgroepe hoofsaaklik uit teenoorgestelde geslagte bestaan het. In vergelykende epidemiologiese studies is die groepe gewoonlik dieselfde met betrekking tot agtergrond etiologie en slegs verskillend wat betref die faktor wat ondersoek word; in hierdie geval die frekwensie van blootstelling aan wyn (hoë frekwensie en langdurige kontak van wyn met tande ). In alle waarskynlikheid is die aanhoudende blootstelling van wynmakers aan wyn die hooffaktor in die verskille (bv. tandoppervlak verlies en tandstatus) in hierdie studie verkry. 'n Sterk positiewe verband is gevind tussen die statisties-geweegde tandoppervlakverlies en die
chronologiese ouderdom van wynmakers. Daar kon egter geen positiewe verband gevind word tussen die aantal diensjare in die wynindustrie en tandoppervlakverlies nie.
Al die mikro-hardheid toetse en mikroskopiese ondersoeke wat ondemeem is, het die nadelige invloed van wyn op glasuur bevestig. 'n Duidelike dosis-respons verwantskap is deur middel van die Mikro-hardheid toetse gedemonstreer. Die werk gedoen met die Skandeer Elektronmikroskoop (SEM) en die Konfokale Laser Skandeer Elektronmikroskoop (CLSM) het beide die effek deur die Mikro-hardheid toets vasgestel, bevestig. Die SEM (drie wyne) en CLSM (twee wyne) ondersoeke het ook verskille in die oppervlak morfologie van glasuur ten opsigte van die blootstelling aan die wyne gedemonstreer. In die geval van die SEM is dit met drie wyne gedemonstreer, terwyl dit in die geval van CSLM twee wyne was. Daar is wel verskille in graad vasgestel deur middel van SEM-ondersoeke. Oppervlak- en benede-oppervlak letsels op glasuur wat blootgestel is aan die twee wyne, is waargeneem met behulp van CSLM.Doctora
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Human resources for oral health care in South Africa : a 2018 update
Full text linkCITATION: Bhayat, A. & Chikte, U. 2019. Human Resources for Oral Health Care in South Africa : a 2018 Update.
International Journal of Environmental Research and Public Health, 16(10):1668, doi:10.3390/ijerph16101668.The original publication is available at https://www.mdpi.comTo describe the current oral health care needs and the number and category of dental personnel required to provide necessary services in South Africa (SA). This is a review of the current disease burden based on local epidemiological studies and the number of oral health personnel registered with the Health Professions Council of South Africa (HPCSA). In SA, oral health services are rendered by oral hygienists, dental therapists, dentists, and dental specialists. Dental caries remains one of the most prevalent conditions, and much of them are untreated. The majority of oral care providers are employed in the private sector even though the majority of the population access the public sector which only offers a basic package of oral care. The high prevalence of caries could be prevented and treated by the public sector. The infrastructure at primary health care facilities needs to be improved so that dentists performing community service can be more effectively utilized. At present, SA requires more dental therapists and oral hygienists to be trained at the academic training institutions.https://www.mdpi.com/1660-4601/16/10/1668Publisher's versio
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Sustainable workforce : South African audiologists and speech therapists
Full text linkCITATION: Pillay, M., et al. 2020. Sustainable workforce : South African Audiologists and Speech Therapists. Human Resources for Health, 18:47, doi:10.1186/s12960-020-00488-6.The original publication is available at https://human-resources-health.biomedcentral.comBackground: Audiologists and Speech Therapists play a vital role in addressing sustainable development goals by
supporting people who are marginalised due to communication challenges. The global burden of disease and poor
social living conditions impact negatively on the development of healthy communication, therefore requiring the
services of Audiologist and Speech therapists. Against this background, we examined the demographic profile and
the supply, need and shortfall of Audiologists and Speech Therapists in South Africa.
Methods: The data set was drawn from the Health Professions Council of South Africa (HPCSA) registers (for 2002–
2017) for the speech, language and hearing professions. This demographic profile of the professions was created
based on the category of health personnel; category of practice, geographical location, population group (race) and
sex. The annual supply was estimated from the HPCSA database while the service–target approach was used to
estimate need. Additional need based on National Health Insurance Bill was also included. Supply–need gaps were
forecast according to three scenarios, which varied according to the future intensity of policy intervention to
increase occupancy of training places: ‘best guess’ (no intervention), ‘optimistic’ (feasible intervention), and
‘aspirational’ (significant intervention) scenarios up to 2030.
Results: Most (i.e. 1548, 47.4%) of the professionals are registered as Audiologists and Speech Therapists, followed
by 33.5% registered as Speech Therapists and 19.1% registered as Audiologists. Around 88.5% professionals
registered as Audiologists and Speech Therapists are practising independently, and 42.6% are practising in the
Gauteng province. The profession is comprised majorly of women (94.6%), and in terms of the population groups
(race), they are mainly classified as white (59.7%). In 2017, in best guess scenario, there is a supply–need gap of
around 2800 professionals. In the absence of any intervention to increase supply capacity, this shortfall will remain
same by the year 2030. By contrast, in aspirational scenario, i.e. supply is increased by 300%, the forecasted shortfall
for 2030 reduces to 2300 from 2800 professionals.
Conclusions: It is clear that without significant interventions, South Africa is likely to have a critical shortfall of
Audiologists and Speech Therapists in 2030. Policy-makers will have to carefully examine issues surrounding the
current framework regulating training of these and associated professionals, in order to respond adequately to
future requirements.https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-020-00488-6Publisher's versio
Perceptions regarding the shortened dental arch among dental practitioners in the Western Cape Province, South Africa
No full textAIM AND OBJECTIVES: This survey was conducted to determine the knowledge of and opinions related to the shortened dental arch (SDA), among dentists in the Western Cape Province, South Africa.
METHODS: The study sample included two consecutive groups, drawn by a process of randomisation from the registered dentist population that included general dentists, specialists, those who had emigrated and retired dentists. A self-administered questionnaire was mailed, e-mailed and/or faxed to those selected. Reminders were either e-mailed or made by telephone over a period of six months.
RESULTS: A final sample of 84 respondents with a mean age of 43 years (SD=11.9) was obtained. This represented a response rate of 23% (n= 84) from the final working sample (n=368), derived from the target group (n=618) originally contacted. All participants completed an informed consent form in which confidentiality was assured. Several respondents (40%) said they had heard about the SDA while at university, which would be in line with the age range of respondents in relation to introduction of the concept into dental curricula. As many as 62% had never read any research articles related to the concept which could partly account for the low response rate. The majority (86%) felt that patients can function with a SDA and that they would recommend acceptance to their patients.
CONCLUSION: Respondents know of the potential benefit that the SDA may have for their patients and see it as a viable alternative treatment option for the partially dentate patient, even though their level of current knowledge of the subject must be considered questionable
The pH Levels of different methamphetamine drug samples on the street market in Cape Town
No full textThe purpose of this study was to determine the pH levels of 29 different samples of methamphetamine on the street market in
Cape Town. The sample was dissolved in water and the pH of each sample determined. The pH levels varied from 3.02 to 7.03 with
an average of 5.0. Seventy-two percent (21) of the samples had a pH level below the saliva “critical pH point of 5.6” and therefore
should cause significant damage to enamel, especially in hyposalivation subjects without a saliva flow. However, about 26% of the
samples had a pH level close to the neutral point and should cause minor damage to enamel. To lessen enamel damage, subjects
should exercise good oral hygiene practice, rinse with a fluoride-containing mouth rinse, drink artificially sweetened drinks, and
eat cheese. It is concluded that most of the methamphetamine samples have a low enough pH to cause direct damage to enamel
especially in hyposalivation subjects
The pH levels of different methamphetamine drug samples on the street market in Cape Town
Full text linkCITATION: Grobler, S. R., Chikte, U. & Westraat, J. 2011. The pH levels of different methamphetamine drug samples on the street market in Cape Town. ISRN Dentistry, 974768, doi:10.5402/2011/974768.The original publication is available at https://onlinelibrary.wiley.comThe purpose of this study was to determine the pH levels of 29 different samples of methamphetamine on the street market in Cape Town. The sample was dissolved in water and the pH of each sample determined. The pH levels varied from 3.02 to 7.03 with an average of 5.0. Seventy-two percent (21) of the samples had a pH level below the saliva “critical pH point of 5.6” and therefore should cause significant damage to enamel, especially in hyposalivation subjects without a saliva flow. However, about 26% of the samples had a pH level close to the neutral point and should cause minor damage to enamel. To lessen enamel damage, subjects should exercise good oral hygiene practice, rinse with a fluoride-containing mouth rinse, drink artificially sweetened drinks, and eat cheese. It is concluded that most of the methamphetamine samples have a low enough pH to cause direct damage to enamel especially in hyposalivation subjects.https://onlinelibrary.wiley.com/doi/10.5402/2011/974768Publisher's versio
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