Synthesis of silver nanoparticles and their role against human and Plasmodium falciparum leucine aminopeptidase
- Authors: Mnkandhla, Dumisani
- Date: 2015
- Subjects: Silver , Nanoparticles , Plasmodium falciparum , Leucine aminopeptidase , Antimalarials , Nanotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4150 , http://hdl.handle.net/10962/d1017911
- Description: Antimalarial drug discovery remains a challenging endeavour as malaria parasites continue to develop resistance to drugs, including those which are currently the last line of defence against the disease. Plasmodium falciparum is the most virulent of the malaria parasites and it delivers its deadliest impact during the erythrocytic stages of the parasite’s life cycle; a stage characterised by elevated catabolism of haemoglobin and anabolism of parasite proteins. The present study investigates the use of nanotechnology in the form of metallic silver nanoparticles (AgNPs) against P. falciparum leucine aminopeptidase (PfLAP), a validated biomedical target involved in haemoglobin metabolism. AgNPs were also tested against the human homolog cytosolic Homo sapiens leucine aminopeptidase (HsLAP) to ascertain their selective abilities. PfLAP and HsLAP were successfully expressed in Escherichia coli BL21(DE3) cells. PfLAP showed optimal thermal stability at 25 °C and optimal pH stability at pH 8.0 with a Km of 42.7 mM towards leucine-p-nitroanilide (LpNA) and a Vmax of 59.9 μmol.ml⁻¹.min⁻¹. HsLAP was optimally stable at 37 °C and at pH 7.0 with a Km of 16.7 mM and a Vmax of 17.2 μmol.ml⁻¹.min⁻¹. Both enzymes exhibited optimal activity in the presence of 2 mM Mn²⁺. On interaction with polyvinylpyrrolidone (PVP) stabilised AgNPs, both enzymes were inhibited to differing extents with PfLAP losing three fold of its catalytic efficiency relative to HsLAP. These results show the ability of AgNPs to selectively inhibit PfLAP whilst having much lesser effects on its human homolog. With the use of available targeting techniques, the present study shows the potential use of nanotechnology based approaches as “silver bullets” that can target PfLAP without adversely affecting the host. However further research needs to be conducted to better understand the mechanisms of AgNP action, drug targeting and the health and safety issues associated with nanotechnology use.
- Full Text:
- Date Issued: 2015
- Authors: Mnkandhla, Dumisani
- Date: 2015
- Subjects: Silver , Nanoparticles , Plasmodium falciparum , Leucine aminopeptidase , Antimalarials , Nanotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4150 , http://hdl.handle.net/10962/d1017911
- Description: Antimalarial drug discovery remains a challenging endeavour as malaria parasites continue to develop resistance to drugs, including those which are currently the last line of defence against the disease. Plasmodium falciparum is the most virulent of the malaria parasites and it delivers its deadliest impact during the erythrocytic stages of the parasite’s life cycle; a stage characterised by elevated catabolism of haemoglobin and anabolism of parasite proteins. The present study investigates the use of nanotechnology in the form of metallic silver nanoparticles (AgNPs) against P. falciparum leucine aminopeptidase (PfLAP), a validated biomedical target involved in haemoglobin metabolism. AgNPs were also tested against the human homolog cytosolic Homo sapiens leucine aminopeptidase (HsLAP) to ascertain their selective abilities. PfLAP and HsLAP were successfully expressed in Escherichia coli BL21(DE3) cells. PfLAP showed optimal thermal stability at 25 °C and optimal pH stability at pH 8.0 with a Km of 42.7 mM towards leucine-p-nitroanilide (LpNA) and a Vmax of 59.9 μmol.ml⁻¹.min⁻¹. HsLAP was optimally stable at 37 °C and at pH 7.0 with a Km of 16.7 mM and a Vmax of 17.2 μmol.ml⁻¹.min⁻¹. Both enzymes exhibited optimal activity in the presence of 2 mM Mn²⁺. On interaction with polyvinylpyrrolidone (PVP) stabilised AgNPs, both enzymes were inhibited to differing extents with PfLAP losing three fold of its catalytic efficiency relative to HsLAP. These results show the ability of AgNPs to selectively inhibit PfLAP whilst having much lesser effects on its human homolog. With the use of available targeting techniques, the present study shows the potential use of nanotechnology based approaches as “silver bullets” that can target PfLAP without adversely affecting the host. However further research needs to be conducted to better understand the mechanisms of AgNP action, drug targeting and the health and safety issues associated with nanotechnology use.
- Full Text:
- Date Issued: 2015
Financial instability in South Africa : trends and interactions within the financial markets
- Authors: Shikwambana, Jamela
- Date: 2007 , 2013-08-06
- Subjects: Finance -- South Africa , Financial institutions -- South Africa , Economic stabilization -- South Africa , Stock exchanges -- South Africa , Stocks -- Prices -- South Africa , Interest rates -- South Africa , Equilibrium (Economics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1043 , http://hdl.handle.net/10962/d1005911 , Finance -- South Africa , Financial institutions -- South Africa , Economic stabilization -- South Africa , Stock exchanges -- South Africa , Stocks -- Prices -- South Africa , Interest rates -- South Africa , Equilibrium (Economics)
- Description: This study seeks to investigate the trends and interactions of market volatility as a source of instability in the South African financial markets. Financial instability can be manifested in the form of banking and currency crisis, institutional failures and extreme asset price volatility. This study, however, focuses on a single aspect of financial instability - asset price volatility. Asset price volatility reflects changes in market expectations as investors react to such changes, and thus on its own is not necessarily a source of instability. However, volatility spillovers can propagate volatility shocks across the market, increasing the risk of widespread instability. Using a combination of graphical and trend analysis as well as more formal estimation techniques, the study examined volatility in the stock, money and foreign exchange markets. To obtain estimates of market volatility, the study experimented with various volatility models that include the GARCH, TARCH and EGARCH. An analysis of volatility interactions and the transmission of volatility shocks across the market is crucial to understanding financial instability. To examine volatility interaction and the transmission of volatility shocks, a VAR model was estimated. This framework allowed us to examine the propagation of shocks across the markets. Volatility in the financial markets was found to be highly persistent and in the case of exchange rates, volatility was also characterised by an increasing trend. Significant linkages between the financial markets were found. The links also extended to the volatility relationship as evidenced by significant volatility spillovers across the markets. While volatility spillovers from the money market were found in the stock market and the foreign exchange market, no volatility spillovers from these markets were found in the money market. Thus the money market was identified as the major source of volatility spillovers and shocks in the financial markets. These results highlighted the role of monetary policy in the financial system, specifically the need to make monetary policy stable and predictable to ensure that interest rate shocks are not an additional source of instability. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2007
- Authors: Shikwambana, Jamela
- Date: 2007 , 2013-08-06
- Subjects: Finance -- South Africa , Financial institutions -- South Africa , Economic stabilization -- South Africa , Stock exchanges -- South Africa , Stocks -- Prices -- South Africa , Interest rates -- South Africa , Equilibrium (Economics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1043 , http://hdl.handle.net/10962/d1005911 , Finance -- South Africa , Financial institutions -- South Africa , Economic stabilization -- South Africa , Stock exchanges -- South Africa , Stocks -- Prices -- South Africa , Interest rates -- South Africa , Equilibrium (Economics)
- Description: This study seeks to investigate the trends and interactions of market volatility as a source of instability in the South African financial markets. Financial instability can be manifested in the form of banking and currency crisis, institutional failures and extreme asset price volatility. This study, however, focuses on a single aspect of financial instability - asset price volatility. Asset price volatility reflects changes in market expectations as investors react to such changes, and thus on its own is not necessarily a source of instability. However, volatility spillovers can propagate volatility shocks across the market, increasing the risk of widespread instability. Using a combination of graphical and trend analysis as well as more formal estimation techniques, the study examined volatility in the stock, money and foreign exchange markets. To obtain estimates of market volatility, the study experimented with various volatility models that include the GARCH, TARCH and EGARCH. An analysis of volatility interactions and the transmission of volatility shocks across the market is crucial to understanding financial instability. To examine volatility interaction and the transmission of volatility shocks, a VAR model was estimated. This framework allowed us to examine the propagation of shocks across the markets. Volatility in the financial markets was found to be highly persistent and in the case of exchange rates, volatility was also characterised by an increasing trend. Significant linkages between the financial markets were found. The links also extended to the volatility relationship as evidenced by significant volatility spillovers across the markets. While volatility spillovers from the money market were found in the stock market and the foreign exchange market, no volatility spillovers from these markets were found in the money market. Thus the money market was identified as the major source of volatility spillovers and shocks in the financial markets. These results highlighted the role of monetary policy in the financial system, specifically the need to make monetary policy stable and predictable to ensure that interest rate shocks are not an additional source of instability. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2007
Cognitive-behavioural treatment of essential hypertension in an urban Xhosa woman: a case study
- Authors: Losinsky, Rory
- Date: 1991
- Subjects: Xhosa (African people) -- Psychology , Women, Xhosa -- Psychology , Hypertension -- Psychosomatic aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3010 , http://hdl.handle.net/10962/d1002519 , Xhosa (African people) -- Psychology , Women, Xhosa -- Psychology , Hypertension -- Psychosomatic aspects
- Description: Essential hypertension has a complex and multiple biological, psychological and social aetiology and remains one of the most serious physical disorders affecting the Black population of South Africa today. Pharmacological treatment has been the predominant approach to blood pressure reduction, but considering that the greater part of essential hypertension has its origin in biobehavioural and cognitive functioning a non-pharmacological treatment approach to essential hypertension is receiving extensive interest both in research and therapeutic practice. This study attempted to implement a specific cognitive-behavioural treatment "package' which was tailored to the emergent aetiology in an urban Xhosa woman suffering from Mild hypertension who was on antihypertensive medication and to evaluate the treatment using a single case-study methodology. A combination of relaxation training and cognitive-behavioural modification was provided over a fifteen week period and evaluated both quantitatively and qualitatively. It was found that a combination of over-weight, occupational stress and anger could have contributed and/or caused the patient's hypertension. The results also show a significant reduction in blood pressure during the treatment phase as well as a reduction in weight, experienced anxiety and angry emotion, and by the end of the study the patient's blood pressure had been reduced to normal levels. Finally the feasibility of using such a treatment approach is discussed in relation to the South African context and the case study method is evaluated as a research tool in light of the findings.
- Full Text:
- Date Issued: 1991
- Authors: Losinsky, Rory
- Date: 1991
- Subjects: Xhosa (African people) -- Psychology , Women, Xhosa -- Psychology , Hypertension -- Psychosomatic aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3010 , http://hdl.handle.net/10962/d1002519 , Xhosa (African people) -- Psychology , Women, Xhosa -- Psychology , Hypertension -- Psychosomatic aspects
- Description: Essential hypertension has a complex and multiple biological, psychological and social aetiology and remains one of the most serious physical disorders affecting the Black population of South Africa today. Pharmacological treatment has been the predominant approach to blood pressure reduction, but considering that the greater part of essential hypertension has its origin in biobehavioural and cognitive functioning a non-pharmacological treatment approach to essential hypertension is receiving extensive interest both in research and therapeutic practice. This study attempted to implement a specific cognitive-behavioural treatment "package' which was tailored to the emergent aetiology in an urban Xhosa woman suffering from Mild hypertension who was on antihypertensive medication and to evaluate the treatment using a single case-study methodology. A combination of relaxation training and cognitive-behavioural modification was provided over a fifteen week period and evaluated both quantitatively and qualitatively. It was found that a combination of over-weight, occupational stress and anger could have contributed and/or caused the patient's hypertension. The results also show a significant reduction in blood pressure during the treatment phase as well as a reduction in weight, experienced anxiety and angry emotion, and by the end of the study the patient's blood pressure had been reduced to normal levels. Finally the feasibility of using such a treatment approach is discussed in relation to the South African context and the case study method is evaluated as a research tool in light of the findings.
- Full Text:
- Date Issued: 1991
Static and ultrasonic elastic moduli of wool, mohair and kemp fibres
- Authors: King, Neville Edwin
- Date: 1969
- Subjects: Moduli theory , Mohair , Wool
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5528 , http://hdl.handle.net/10962/d1012640 , Moduli theory , Mohair , Wool
- Description: Fibres used in textiles can be classified broadly into natural fibres and synthetic fibres. Natural fibres can be either animal, such as wool, mohair and camel hair, or vegetable such as cotton, flax and hemp. In the development of synthetic fibres numerous polymers have emerged which have no real natural counterpart and are unique in their mechanical and chemical behaviour. Often the synthetic counterpart of a natural fibre has properties with certain advantages from the textile point of view, but, simultaneously, may exhibit other properties which have disadvantages. Nylon 6 and nylon 6-6, for exemple, are extremely strong and generally easier to dye than animal fibres. On the other hand, they absorb relatively little water vapour and therefore do not give the buffering action characteristic of hygroscopic fibres, once they are woven or knitted into cloth. All textile fibres belong to the chemical class of polymers, i.e. they are made up of repeating molecular units which are linked together to form long chains. In wool the chains are made up of amino-acids which cluster together to form protein chains. Three of these protein chains, coil around each other to form what is termed a proto-fibril. The proto-fibrils make up the micro-fibrils, each of these consisting of eleven of the three chain proto-fibrils. The micro-fibrils, in turn, pack together in bundles which run parallel to the length of the wool fibre and are termed macro-fibrils. Sulphur rich amino-acids fill up the spaces between the micro-fibrils forming a matrix which binds the system into a continuous material. Intro., p. 1.
- Full Text:
- Date Issued: 1969
- Authors: King, Neville Edwin
- Date: 1969
- Subjects: Moduli theory , Mohair , Wool
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5528 , http://hdl.handle.net/10962/d1012640 , Moduli theory , Mohair , Wool
- Description: Fibres used in textiles can be classified broadly into natural fibres and synthetic fibres. Natural fibres can be either animal, such as wool, mohair and camel hair, or vegetable such as cotton, flax and hemp. In the development of synthetic fibres numerous polymers have emerged which have no real natural counterpart and are unique in their mechanical and chemical behaviour. Often the synthetic counterpart of a natural fibre has properties with certain advantages from the textile point of view, but, simultaneously, may exhibit other properties which have disadvantages. Nylon 6 and nylon 6-6, for exemple, are extremely strong and generally easier to dye than animal fibres. On the other hand, they absorb relatively little water vapour and therefore do not give the buffering action characteristic of hygroscopic fibres, once they are woven or knitted into cloth. All textile fibres belong to the chemical class of polymers, i.e. they are made up of repeating molecular units which are linked together to form long chains. In wool the chains are made up of amino-acids which cluster together to form protein chains. Three of these protein chains, coil around each other to form what is termed a proto-fibril. The proto-fibrils make up the micro-fibrils, each of these consisting of eleven of the three chain proto-fibrils. The micro-fibrils, in turn, pack together in bundles which run parallel to the length of the wool fibre and are termed macro-fibrils. Sulphur rich amino-acids fill up the spaces between the micro-fibrils forming a matrix which binds the system into a continuous material. Intro., p. 1.
- Full Text:
- Date Issued: 1969
The effect of different levels and intervals of application of ammonium sulphate on the growth, chemical composition and yield of cayenne and queen pineapple plants under field conditions
- Van Lelyveld, Louis Johannes
- Authors: Van Lelyveld, Louis Johannes
- Date: 1965
- Subjects: Pineapple -- Crop yields , Plants -- Nutrition -- South Africa , Growth (Plants) , Nitrogen fertilizers , Field Crops -- Nutrition , Ammonium sulfate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4263 , http://hdl.handle.net/10962/d1013422
- Description: From the Introduction. The fertilisation of pineapples in the Eastern Cape Province is still a relatively new practice which started approximately twelve years ago. Even after this time many growers still insist that pineapples can be grown without fertilisation on virgin soils. As the available virgin soil decreased, however, so the interest in fertiliser application increased. Very little basic research on the fertiliser requirements of pineapples in the Eastern Cape was done to serve as a guide to growers. The available advisory literature by le Roux (1951), Malan (1954) and Lewcock (1956) were based on overseas experience. When pineapple research was started on a large scale, in 1955, it was realised that emphasis should be placed on the nutritional requirements on virgin as well as replanted soils. From initial experiments it was clear that the main response in plant growth and yield was obtained from nitrogenous fertilisers.
- Full Text:
- Date Issued: 1965
- Authors: Van Lelyveld, Louis Johannes
- Date: 1965
- Subjects: Pineapple -- Crop yields , Plants -- Nutrition -- South Africa , Growth (Plants) , Nitrogen fertilizers , Field Crops -- Nutrition , Ammonium sulfate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4263 , http://hdl.handle.net/10962/d1013422
- Description: From the Introduction. The fertilisation of pineapples in the Eastern Cape Province is still a relatively new practice which started approximately twelve years ago. Even after this time many growers still insist that pineapples can be grown without fertilisation on virgin soils. As the available virgin soil decreased, however, so the interest in fertiliser application increased. Very little basic research on the fertiliser requirements of pineapples in the Eastern Cape was done to serve as a guide to growers. The available advisory literature by le Roux (1951), Malan (1954) and Lewcock (1956) were based on overseas experience. When pineapple research was started on a large scale, in 1955, it was realised that emphasis should be placed on the nutritional requirements on virgin as well as replanted soils. From initial experiments it was clear that the main response in plant growth and yield was obtained from nitrogenous fertilisers.
- Full Text:
- Date Issued: 1965
A quantitative investigation of the absorption of certain cations by whole plants and plant tissues
- Cresswell, Christopher Frederick
- Authors: Cresswell, Christopher Frederick
- Date: 1959 , 2014-07-24
- Subjects: Cations -- Absorption and adsorption , Plant tissues
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4262 , http://hdl.handle.net/10962/d1013335
- Description: Introduction: Part 1. Greenhouse studies were conducted to investigate the absorption of sodium, potassium, calcium and magnesium by lemon seedlings. The plants were grown in controlled nutrient solutions and analysis of the plant material was made to determine the relationship between the four cations in the different plant organs. Results of the experiment may be summarized as follows:- The occurrence of leaf burn appeared to be associated with a low calcium content, together with a high sodium, potassium or sodium + potassium content. The development of the seedlings was shown to be markedly influenced by the level of calcium supply and to a much lesser degree by the level of potassium supplied. The concentration of sodium, potassium, calcium and magnesium in the stem and leaf varied with position of the tissues on the main axis. The level of sodium was found to influence the distribution of sodium in the leaves, and the sodium content of the leaf, stem and root tissues gave a good reflection of the level of sodium supplied. The effect of the sodium treatment on the uptake of potassium appeared to be dependent on the calcium content of the tissues. Sodium treatment was found not to affect the leaf calcium content. In the stem and root tissues the calcium content was reduced when the calcium level in the nutrient medium was low, and increased the calcium content of these two tissues at the higher level of calcium supply. The sodium supply was shown to reduce the leaf magnesium only slightly, and its affect on the magnesium content of the stem and root tissues was shown to be dependent on the level of calcium supplied. The potassium content of the leaves, stems and roots increased when the supply of potassium was raised. Increasing the potassium level in the nutrient supply was found to cause a very slight reduction in the sodium content of the leaf, but did not affect the sodium content of the stem and root. Potassium did not affect the calcium content of the leaves and increased the stem calcium when sodium was not present in the nutrient media in high concentrations. In the roots potassium only increase the calcium content at the upper level of calcium supply. The magnesium content of the leaf and stem tissues was reduced as the potassium supply was increased. In the roots the general trend was for the magnesium content to increase when the level of potassium treatment was raised. The calcium content of all the plant parts increased with a rise in the calcium supply, the stem and root tissues having a greater percentage increase than the leaves. The sodium content of the plant tissue was reduced as the level of calcium supply was raised. The leaf potassium content decreased with a higher calcium level of supply. In the stem and roots the potassium content was increased by doubling the calcium supply. The calcium treatment had no influence on the magnesium content of the foliage, but in the stem and root tissues a decrease in magnesium content resulted from an increase in the calcium supply. Part II Potato tuber tissue and carrot root tissue were used as experimental material in the investigation of sodium9 potassium9 and calcium uptake by storage tissue. It was shown that when the tissue disks are transferred from distilled water to a solution of salts there is a rapid initial uptake of cation which is neither particularly selective, nor related to metabolism, but dependent on the external concentration. On the other hand, the prolonged active accumulation of cation exhibits selectivity. Potassium absorption by potato tuber tissue was shown to be stimulated by sodium9 whereas the potassium and calcium absorption by carrot root tissue was shown to be reduced by sodium. Similarly the sodium absorption by the carrot root tissue was reduced by potassium, thus suggesting that the cations compete with one another for the same absorption mechanism.
- Full Text:
- Date Issued: 1959
- Authors: Cresswell, Christopher Frederick
- Date: 1959 , 2014-07-24
- Subjects: Cations -- Absorption and adsorption , Plant tissues
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4262 , http://hdl.handle.net/10962/d1013335
- Description: Introduction: Part 1. Greenhouse studies were conducted to investigate the absorption of sodium, potassium, calcium and magnesium by lemon seedlings. The plants were grown in controlled nutrient solutions and analysis of the plant material was made to determine the relationship between the four cations in the different plant organs. Results of the experiment may be summarized as follows:- The occurrence of leaf burn appeared to be associated with a low calcium content, together with a high sodium, potassium or sodium + potassium content. The development of the seedlings was shown to be markedly influenced by the level of calcium supply and to a much lesser degree by the level of potassium supplied. The concentration of sodium, potassium, calcium and magnesium in the stem and leaf varied with position of the tissues on the main axis. The level of sodium was found to influence the distribution of sodium in the leaves, and the sodium content of the leaf, stem and root tissues gave a good reflection of the level of sodium supplied. The effect of the sodium treatment on the uptake of potassium appeared to be dependent on the calcium content of the tissues. Sodium treatment was found not to affect the leaf calcium content. In the stem and root tissues the calcium content was reduced when the calcium level in the nutrient medium was low, and increased the calcium content of these two tissues at the higher level of calcium supply. The sodium supply was shown to reduce the leaf magnesium only slightly, and its affect on the magnesium content of the stem and root tissues was shown to be dependent on the level of calcium supplied. The potassium content of the leaves, stems and roots increased when the supply of potassium was raised. Increasing the potassium level in the nutrient supply was found to cause a very slight reduction in the sodium content of the leaf, but did not affect the sodium content of the stem and root. Potassium did not affect the calcium content of the leaves and increased the stem calcium when sodium was not present in the nutrient media in high concentrations. In the roots potassium only increase the calcium content at the upper level of calcium supply. The magnesium content of the leaf and stem tissues was reduced as the potassium supply was increased. In the roots the general trend was for the magnesium content to increase when the level of potassium treatment was raised. The calcium content of all the plant parts increased with a rise in the calcium supply, the stem and root tissues having a greater percentage increase than the leaves. The sodium content of the plant tissue was reduced as the level of calcium supply was raised. The leaf potassium content decreased with a higher calcium level of supply. In the stem and roots the potassium content was increased by doubling the calcium supply. The calcium treatment had no influence on the magnesium content of the foliage, but in the stem and root tissues a decrease in magnesium content resulted from an increase in the calcium supply. Part II Potato tuber tissue and carrot root tissue were used as experimental material in the investigation of sodium9 potassium9 and calcium uptake by storage tissue. It was shown that when the tissue disks are transferred from distilled water to a solution of salts there is a rapid initial uptake of cation which is neither particularly selective, nor related to metabolism, but dependent on the external concentration. On the other hand, the prolonged active accumulation of cation exhibits selectivity. Potassium absorption by potato tuber tissue was shown to be stimulated by sodium9 whereas the potassium and calcium absorption by carrot root tissue was shown to be reduced by sodium. Similarly the sodium absorption by the carrot root tissue was reduced by potassium, thus suggesting that the cations compete with one another for the same absorption mechanism.
- Full Text:
- Date Issued: 1959
- «
- ‹
- 1
- ›
- »