An evaluation of different methods of preparation of quartz grains for study of their surface features by scanning electron microscopy
- Lewis, Colin A, Armstrong, Glynis A S
- Authors: Lewis, Colin A , Armstrong, Glynis A S
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6705 , http://hdl.handle.net/10962/d1006741
- Description: Sediments from periglacial and glacial environments were subjected to initial preparation and portions were subsequently further prepared using either the dichromate or the hydrogen peroxide method before being examined by scanning electron microscopy. Statistically significant differences did not occur in the results obtained for samples subjected only to initial or to initial and either of the two further preparations: it is concluded that initial preparation is satisfactory and further preparation unnecessary.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A , Armstrong, Glynis A S
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6705 , http://hdl.handle.net/10962/d1006741
- Description: Sediments from periglacial and glacial environments were subjected to initial preparation and portions were subsequently further prepared using either the dichromate or the hydrogen peroxide method before being examined by scanning electron microscopy. Statistically significant differences did not occur in the results obtained for samples subjected only to initial or to initial and either of the two further preparations: it is concluded that initial preparation is satisfactory and further preparation unnecessary.
- Full Text:
- Date Issued: 1994
In vitro release of propranolol hydrochloride from topical vehicles
- Smith, Eric W, Haigh, John M
- Authors: Smith, Eric W , Haigh, John M
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6435 , http://hdl.handle.net/10962/d1006612
- Description: Transdermal drug delivery is becoming increasingly important and for this reason it is clear that academia must ensure that current graduates are knowledgeable in all facets of topical drug administration. An in vitro diffusion cell experiment was designed to demonstrate the rate of release of propranolol hydrochloride (PHC) from three different topical vehicles: (i) an oil-in-water cream; (ii) a gel; and (iii) anointment. This experiment was performed by final-year students enroled in an undergraduate course on percutaneous absorption. In vitro release of PHC from the three bases to an aqueous receptor phase through silicone membrane was monitored spectrophotometrically at a wavelength of 290 nm. By monitoring and attempting to explain the numerous possible reasons for the different rates of drug release from the three vehicles, it was hoped that the students would gain a better understanding of the complexities of transdermal drug administration. Overall, the experiment would appear to be a good model for student investigation into factors affecting the release of drugs from topical formulations.
- Full Text:
- Date Issued: 1994
- Authors: Smith, Eric W , Haigh, John M
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6435 , http://hdl.handle.net/10962/d1006612
- Description: Transdermal drug delivery is becoming increasingly important and for this reason it is clear that academia must ensure that current graduates are knowledgeable in all facets of topical drug administration. An in vitro diffusion cell experiment was designed to demonstrate the rate of release of propranolol hydrochloride (PHC) from three different topical vehicles: (i) an oil-in-water cream; (ii) a gel; and (iii) anointment. This experiment was performed by final-year students enroled in an undergraduate course on percutaneous absorption. In vitro release of PHC from the three bases to an aqueous receptor phase through silicone membrane was monitored spectrophotometrically at a wavelength of 290 nm. By monitoring and attempting to explain the numerous possible reasons for the different rates of drug release from the three vehicles, it was hoped that the students would gain a better understanding of the complexities of transdermal drug administration. Overall, the experiment would appear to be a good model for student investigation into factors affecting the release of drugs from topical formulations.
- Full Text:
- Date Issued: 1994
Insertion of a measurable function
- Authors: Kotzé, W , Kubiak, T
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6785 , http://hdl.handle.net/10962/d1006928
- Description: Some theorems on the existence of continuous real-valued functions on a topological space (for example, insertion, extension, and separation theorems) can be proved without involving uncountable unions of open sets. In particular, it is shown that well-known characterizations of normality (for example the Katětov-Tong insertion theorem, the Tietze extension theorem, Urysohn's lemma) are characterizations of normal σ-rings. Likewise, similar theorems about extremally disconnected spaces are true for σ-rings of a certain type. This σ-ring approach leads to general results on the existence of functions of class α.
- Full Text:
- Date Issued: 1994
- Authors: Kotzé, W , Kubiak, T
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6785 , http://hdl.handle.net/10962/d1006928
- Description: Some theorems on the existence of continuous real-valued functions on a topological space (for example, insertion, extension, and separation theorems) can be proved without involving uncountable unions of open sets. In particular, it is shown that well-known characterizations of normality (for example the Katětov-Tong insertion theorem, the Tietze extension theorem, Urysohn's lemma) are characterizations of normal σ-rings. Likewise, similar theorems about extremally disconnected spaces are true for σ-rings of a certain type. This σ-ring approach leads to general results on the existence of functions of class α.
- Full Text:
- Date Issued: 1994
Protalus ramparts and the altitude of the local equilibrium line during the last glacial stage in Bokspruit, East Cape Drakensberg, South Africa
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6694 , http://hdl.handle.net/10962/d1006729
- Description: A ridge of unconsolidated debris at an altitude of 2000 m, located beneath cliffs in the East Cape Drakensberg of South Africa, is interpreted on morphological and sedimentological evidence as a protalus rampart. The rampart is believed to have formed in the Bottelnek Stadial, after 27 000 BP and before 13 000 BP, and provides evidence of perennial snowbeds and at least discontinuous permafrost in the East Cape Drakensberg during that Stadial.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6694 , http://hdl.handle.net/10962/d1006729
- Description: A ridge of unconsolidated debris at an altitude of 2000 m, located beneath cliffs in the East Cape Drakensberg of South Africa, is interpreted on morphological and sedimentological evidence as a protalus rampart. The rampart is believed to have formed in the Bottelnek Stadial, after 27 000 BP and before 13 000 BP, and provides evidence of perennial snowbeds and at least discontinuous permafrost in the East Cape Drakensberg during that Stadial.
- Full Text:
- Date Issued: 1994
Ringing the changes
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6185 , http://hdl.handle.net/10962/d1012383
- Description: The restoration of the bells of the Grahamstown Cathedral heralds a new interest in bell-ringing in South Africa. Although the music of ringing bells is part of our heritage, few people know much about the development, or even the rules of change ringing. This is the form of ringing typical of Britain and, increasingly, of Australia, New Zealand, U.S.A., Canada, and southern Africa. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6185 , http://hdl.handle.net/10962/d1012383
- Description: The restoration of the bells of the Grahamstown Cathedral heralds a new interest in bell-ringing in South Africa. Although the music of ringing bells is part of our heritage, few people know much about the development, or even the rules of change ringing. This is the form of ringing typical of Britain and, increasingly, of Australia, New Zealand, U.S.A., Canada, and southern Africa. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
The contradictions of community politics: the African petty bourgeoisie and the New Brighton Advisory Board, c1937-1952
- Authors: Baines, Gary F
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6147 , http://hdl.handle.net/10962/d1003831
- Full Text: false
- Date Issued: 1994
- Authors: Baines, Gary F
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6147 , http://hdl.handle.net/10962/d1003831
- Full Text: false
- Date Issued: 1994
The selection and use of natural and synthetic membranes for in vitro diffusion experiments
- Haigh, John M, Smith, Eric W
- Authors: Haigh, John M , Smith, Eric W
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6379 , http://hdl.handle.net/10962/d1006297
- Description: The following membranes are discussed: human skin; animal models (including mouse, hairless mouse, rat, guinea pig, rabbit, monkey, pig, shed snake skin, egg-shell membrane, and synthetic stratum corneum); and synthetic membranes (including cellulose media, filter membranes, and synthetic polymers). Membrane integrity and diffusive characteristics are also considered.
- Full Text:
- Date Issued: 1994
- Authors: Haigh, John M , Smith, Eric W
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6379 , http://hdl.handle.net/10962/d1006297
- Description: The following membranes are discussed: human skin; animal models (including mouse, hairless mouse, rat, guinea pig, rabbit, monkey, pig, shed snake skin, egg-shell membrane, and synthetic stratum corneum); and synthetic membranes (including cellulose media, filter membranes, and synthetic polymers). Membrane integrity and diffusive characteristics are also considered.
- Full Text:
- Date Issued: 1994
The South African elections of 1994: the remaking of a dominant-party state
- Authors: Southall, R
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6197 , http://hdl.handle.net/10962/d1008561
- Description: The South African elections of 1994 constituted one of those rare historical moments when humankind made a significant step forward. The peaceful culmination of a liberation struggle, which for years many had feared would end in a bloodbath, registered not only a triumph for the democratic ideal but the resounding defeat of racism as an organising principle of government. If its more recent reference point was the collapse of dictatorial régimes throughout Eastern Europe during 1989–90, it can more distantly be identified as following in the grand tradition of 1789, confirming and extending and elaborating the ‘rights of man’. Yet historical ‘progress’ rarely unfolds in an uncomplicated way, and — however momentous and however much the external world may be willing it to succeed — South Africa's new democracy, by fairly general agreement, faces daunting tasks.
- Full Text:
- Date Issued: 1994
- Authors: Southall, R
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6197 , http://hdl.handle.net/10962/d1008561
- Description: The South African elections of 1994 constituted one of those rare historical moments when humankind made a significant step forward. The peaceful culmination of a liberation struggle, which for years many had feared would end in a bloodbath, registered not only a triumph for the democratic ideal but the resounding defeat of racism as an organising principle of government. If its more recent reference point was the collapse of dictatorial régimes throughout Eastern Europe during 1989–90, it can more distantly be identified as following in the grand tradition of 1789, confirming and extending and elaborating the ‘rights of man’. Yet historical ‘progress’ rarely unfolds in an uncomplicated way, and — however momentous and however much the external world may be willing it to succeed — South Africa's new democracy, by fairly general agreement, faces daunting tasks.
- Full Text:
- Date Issued: 1994
Uncertainty and fear - but restoration completed
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6169 , http://hdl.handle.net/10962/d1012359
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6169 , http://hdl.handle.net/10962/d1012359
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
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