In the medial temporal lobe,there are specific types of neural cells such as place cells, head-direction cells, grid cells, and boundary vector cells which involved in cognitive map and spatial memory. Hippocampal “place cells” encode the rat’s location within an open environment independently of its orientation and fire in the specific position. The complementary encoding of the orientation, independently of location, is done by “head-direction cells” .I think all of them are pyramidal neurons. So Is there any physiological or anatomical difference between these kinds of cell?
Place Cells:
A place cell is a type of pyramidalneuron within the hippocampus that becomes active when the animal enters a particular place in the environment; this place is known as the place field. A given place cell will have only one, or a few, place fields in a typical small laboratory environment, but more in a larger region ( Fenton, et al, 2008). There is no apparent topography to the pattern of place fields, unlike other brain areas such as visual cortex - neighboring place cells are as likely to have distant fields as neighboring ones( O’Keefe John, et al, 1998). In a different environment, typically about half the place cells will still have place fields, but these will be in new places unrelated to their former locations ( Muller and Kubie, 1987).
The place cells are thought, collectively, to act as a cognitive representation of a specific location in space, known as a cognitive map ( O’Keefe John, 1978 ). Place cells work with other types of neurons in the hippocampus and surrounding regions to perform this kind of spatial processing ( Redei George, 2008 ). but the ways in which they function within the hippocampus are still being researched.[6]
Studies with rats have shown that place cells tend to fire quickly when a rat enters a new, open environment, however outside of a firing field, place cells tend to be relatively inactive (Bures, et al, 1997). Together place cells are thought to form a “Cognitive map” in which they have localized firing patterns called place fields ( Jeffery, K. 2007). Place cell firing patterns are often determined by external sensory information and the local environment. Place cells have proven to have the ability to suddenly change their firing pattern from one pattern to another, a phenomenon known as “re-mapping” and though place cells do change according to the external environment, they are stabilized by attractor dynamics which “enable the system to resist small changes in sensory input but respond collectively and coherently to large ones” ( Jeffery, K. 2007).
Although place cells are part of a non-sensory cortical system, their firing behavior is strongly correlated to sensory input. Place cells fire when an animal is located in parts of the environment known as place fields (Smith David and Sheri,2006). These circuits may have important implications for memory, as they provide the spatial context for memories and past experiences.[9] Like many other parts of the brain, place cell circuits are dynamic. They are constantly adjusting and remapping to suit the current location and experience of the brain. Place cells do not work alone to create visuospatial representation; they are a part of a complex circuit that informs place awareness and place memory (Smith David and Sheri,2006).
Grid Cells:
Grid cells are neurons that fire when a freely moving animal traverses a set of small regions (firing fields) which are roughly equal in size and arranged in a periodic triangular array that covers the entire available environment (Hafting, et al, 2005). Cells with this firing pattern have been found in all layers of the dorsocaudal medial entorhinal cortex (dMEC), but cells in different layers tend to differ in other respects. Layer II contains the largest density of pure grid cells, in the sense that they fire equally regardless of the direction in which an animal traverses a grid location. Grid cells from deeper layers are intermingled with conjunctive cells (Sargolini, 2006) and head direction cells (i.e. in layers III, V and VI there are cells with a grid-like pattern that fire only when the animal is facing a particular direction) ( Sargolini, et al, 2006).
Grid cells that lie next to one another (i.e., cells recorded from the same electrode) usually show the same grid spacing and orientation, but their grid vertices are displaced from one another by apparently random offsets. Cells recorded from separate electrodes at a distance from one another, however, frequently show different grid spacings. Cells that are located more ventrally (that is, farther from the dorsal border of the MEC) generally have larger firing fields at each grid vertex, and correspondingly greater spacing between the grid vertices (Hafting, et al, 2005). The total range of grid spacings is not well established: the initial report described a roughly twofold range of grid spacings (from 39 cm to 73 cm) across the dorsalmost part (upper 25%) of the MEC(Hafting, et al, 2005), but there are indications of considerably larger grid scales in more ventral zones. Brun et al. (2008) recorded grid cells from multiple levels in rats running along an 18 meter track, and found that the grid spacing expanded from about 25 cm in their dorsalmost sites to about 3 m at the ventralmost sites (Brun, et al, 2008). These recordings only extended 3/4 of the way to the ventral tip, so it is possible that even larger grids exist.
Grid cell activity does not require visual input, since grid patterns remain unchanged when all the lights in an environment are turned off (Hafting, et al, 2005).When visual cues are present, however, they exert strong control over the alignment of the grids: Rotating a cue card on the wall of a cylinder causes grid patterns to rotate by the same amount(Hafting, et al, 2005). Grid patterns appear on the first entrance of an animal into a novel environment, and usually remain stable thereafter(Hafting, et al, 2005). When an animal is moved into a completely different environment, grid cells maintain their grid spacing, and the grids of neighboring cells maintain their relative offsets(Hafting, et al, 2005).
Possible Functions:
Many species of mammals can keep track of spatial location even in the absence of visual, auditory, olfactory, or tactile cues, by integrating their movements—the ability to do this is referred to in the literature as path integration. A number of theoretical models have explored mechanisms by which path integration could be performed by neural networks. In most models, such as those of Samsonovich and McNaughton (1997). ( Samsonovicha,) or Burak and Fiete (2009) the principal ingredients are:
(1) an internal representation of position,
(2) internal representations of the speed and direction of movement, and
(3) a mechanism for shifting the encoded position by the right amount when the animal moves.
Because cells in the MEC encode information about position of grid cells (Hafting, et al, 2005)) and movement (head direction cells and conjunctive position-by-direction cell ( Sargolini, et al, 2006), this area is currently viewed as the most promising candidate for the place in the brain where path integration occurs. However, the question remains unresolved, as in humans the entorhinal cortex does not appear to be required for path integration (Shrager, et al , 2008). Burak and Fiete (2009) showed that a computational simulation of the grid cell system was capable of performing path integration to a high level of accuracy ( Burak, et al, 2009). However, more recent theoretical work has suggested that grid cells might perform a more general denoising process not necessarily related to spatial processing ( Sreenivasan and Fiete, 2011).
Hafting et al. (2005) suggested that a place code is computed in the entorhinal cortex and fed into the hippocampus, which may make the associations between place and events that are needed for the formation of memories.
In contrast to a hippocampal place cell, a grid cell has multiple firing fields, with regular spacing, which tessellate the environment in a hexagonal pattern. The unique properties of grid cells are as follows:
1. Grid cells have firing fields dispersed over the entire environment (in contrast to place fields which are restricted to certain specific regions of the environment)
2. The firing fields are organized into a hexagonal lattice
3. Firing fields are generally equally spaced apart, such that the distance from one firing field to all six adjacent firing fields is approximately the same (though when an environment is resized, the field spacing may shrink or expand differently in different directions; Barry et al. 2007)
4. Firing fields are equally positioned, such that the six neighboring fields are located at approximately 60 degree increments
The grid cells are anchored to external landmarks, but persist in darkness, suggesting that grid cells may be part of a self-motion based map of the spatial environment.
References:
1. Fenton, A. A.; Kao, H. Y.; Neymotin, S. A.; Olypher, A; Vayntrub, Y; Lytton, W. W.; Ludvig, N (2008). "Unmasking the CA1 ensemble place code by exposures to small and large environments: More place cells and multiple, irregularly arranged, and expanded place fields in the larger space". Journal of Neuroscience 28 (44): 11250–62. doi:10.1523/JNEUROSCI.2862-08.2008. PMC 2695947. PMID 18971467. edit
2. O'Keefe, J; Burgess, N; Donnett, J. G.; Jeffery, K. J.; Maguire, E. A. (1998). "Place cells, navigational accuracy, and the human hippocampus". Philosophical Transactions of the Royal Society B: Biological Sciences 353 (1373): 1333–40. doi:10.1098/rstb.1998.0287. PMC 1692339. PMID 9770226. edit
3. Muller, R. U.; Kubie, J. L. (1987). "The effects of changes in the environment on the spatial firing of hippocampal complex-spike cells". The Journal of neuroscience : the official journal of the Society for Neuroscience 7 (7): 1951–68. PMID 3612226. edit
4. O'Keefe, John (1978). The Hippocampus as a Cognitive Map. ISBN 978-0198572060.
5. Muir, Gary; David K. Bilkey (1 June 2001). "Instability in the Place Field Location of Hippocampal Place Cells after Lesions Centered on the Perirhinal Cortex". The Journal of Neuroscience 21 (11): 4016–4025. PMID 11356888. Cite uses deprecated parameters (help)
6. Redei, George (2008). Encyclopedia of Genetics, Genomics, Proteomics, and Informatics. p. 1501. ISBN 978-1-4020-6753-2. .
7. Bures, J.; A.A. Fenton, Yu Kaminsky, and L. Zinyuk (7 January 1997). "Place cells and place navigation". Proceedings of the National Academy of Sciences 94 (1): 343–350. doi:10.1073/pnas.94.1.343. PMC 19339. Cite uses deprecated parameters (help)
8. Jeffery, Kathryn (2007). "Integration of Sensory Inputs to Place Cells: what, where, why, and how?". Hippocampus 17 (9): 775–785. doi:10.1002/hipo.20322. PMID 17615579. Retrieved 2013-10-18.
9. Smith, David; Sheri Mizumori (June 2006). "Hippocampal Place Cells, Context, and Episodic Memory". Hippocampus 16 (9): 716–729. doi:10.1002/hipo.20208. PMID 16897724. Cite uses deprecated parameters (help)
10. Hafting, T.; Fyhn, M.; Molden, S.; Moser, M. -B.; Moser, E. I. (2005). "Microstructure of a spatial map in the entorhinal cortex". Nature 436 (7052): 801–806. Bibcode:2005Natur.436..801H. doi:10.1038/nature03721. PMID 15965463. edit
11. Sargolini, F. (5 May 2006). "Conjunctive Representation of Position, Direction, and Velocity in Entorhinal Cortex". Science 312 (5774): 758–762. Bibcode:2006Sci...312..758S. doi:10.1126/science.1125572. PMID 16675704. |accessdate= requires |url= (help)
12. Sargolini, F.; Fyhn, M.; Hafting, T.; McNaughton, B. L.; Witter, M. P.; Moser, M. -B.; Moser, E. I. (2006). "Conjunctive Representation of Position, Direction, and Velocity in Entorhinal Cortex". Science 312 (5774): 758–762. Bibcode:2006Sci...312..758S. doi:10.1126/science.1125572. PMID 16675704. edit
13. Brun, V. H.; Solstad, T.; Kjelstrup, K. B.; Fyhn, M.; Witter, M. P.; Moser, E. I.; Moser, M. B. (2008). "Progressive increase in grid scale from dorsal to ventral medial entorhinal cortex". Hippocampus 18 (12): 1200–1212. doi:10.1002/hipo.20504. PMID 19021257.
14. Samsonovich a, M. A. B. (1997). "Path integration and cognitive mapping in a continuous attractor neural network model". Journal of Neuroscience 17 (15): 5900–5920. PMID 9221787.
15. Burak, Y.; Fiete, I. R.; Sporns, O. (2009). "Accurate Path Integration in Continuous Attractor Network Models of Grid Cells". In Sporns, Olaf. PLoS Computational Biology 5 (2): e1000291. doi:10.1371/journal.pcbi.1000291. PMC 2632741. PMID 19229307.
16. Shrager, Y.; Kirwan, C. B.; Squire, L. R. (2008). "Neural basis of the cognitive map: Path integration does not require hippocampus or entorhinal cortex". Proceedings of the National Academy of Sciences 105 (33): 12034. Bibcode:2008PNAS..10512034S. doi:10.1073/pnas.0805414105. PMC 2575247. PMID 18687893.
17. Sreenivasan, S; Fiete, I (2011). "Grid cells generate an analog error-correcting code for singularly precise neural computation". Nature Neuroscience 14 (10): 1330–7. doi:10.1038/nn.2901. PMID 21909090.
18. http://blog.brainfacts.org/2013/08/human-grid-cells/
Dear Vitthalrao
thanks alot for your explicit answer. you compared the function of them. But I'm looking for the physiological or anatomical differences such as extra gated channel, sensitive to the specific ion or so on which lead to such function.
Dear Hossein,
One difference is location: place cells are mainly in CA1 and CA3, head direction cells in the anterior thalamus, subiculum and entorhinal cortex; grid cells are mostly in the medial entorhinal cortex. Grid cells are spiny stellate cells, which is subgroup of excitatory projection neurons with some morphological and physiological specificity (Alonso A. and Klink R. (1993) Differential electroresponsiveness of stellate and pyramidal-like cells of medial entorhinal cortex layer II. J. Neurophysiol. 70, 128–143.; Neuroscience. 2000;96(3):515-22. Morphology of spiny neurons in the human entorhinal cortex: intracellular filling with lucifer yellow. Mikkonen M1, Pitkänen A, Soininen H, Alafuzoff I, Miettinen R.; see also papers from the Hasselmo group).
An obvious difference is their receptive/tuning properties, with the caveat that many grid cells have head-direction tuning, too.
But if you're looking for some obvious marker, e.g. selective expression of an ion channel or a calcium binding protein, I think no such thing has been reported. There may be more subtle differences, e.g. I they may differ in the extent of their Ih currents (see again Hasselmo, e.g. Time constants of h current in layer ii stellate cells differ along the dorsal to ventral axis of medial entorhinal cortex. Giocomo LM, Hasselmo ME. J Neurosci. 2008 Sep 17;28(38):9414-25. doi: 0.1523/JNEUROSCI.3196-08.2008. or J Neurophysiol. 2010 Jul;104(1):258-70. doi: 10.1152/jn.00492.2009. Epub 2010 May 5. Cholinergic modulation of the resonance properties of stellate cells in layer II of medial entorhinal cortex. Heys JG1, Giocomo LM, Hasselmo ME.).
Dr. Burgess said:
"The differences between grid cells and place cells may well be due to their inputs, although some of the stellate cells in layer II of medial entorhinal cortex are probably grid cells, and they have some differences to pyramidal cells."
Medial entorhinal cortex has two principal cells. They are stellate and pyramidal cells. Stellate cells are having round shaped soma and pyramidal cells are having pyramidal shaped soma. The connections between the stellate cells are mainly inhibitory in nature, inhibition being provided by the parvalbumin interneurons where place cells have excitatory connections between them. Stellate cells are seen mainly in the second layer of the medial entorhinal cortex where as pyramidal cells are found mainly in the deeper layers.
Research Group, A. D. T. and Science Association, Shardabai Pawar Mahila Mahavidyalaya, Shardanagar, Malegaon (Baramati) Dist. Pune – 413115.
“Dr. APIS” SCIENCE SPECTRUM
Objective: To Establish the Repository of Contributions of Eminent Scholars and Information on Science and Culture For The Society.
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---------------------Grid cells and Place Cells of Hippocampus------------------------------------------------------------------------------------------------------------------------------------------------
Grid cells and place cells are part of a space mapping circuitry that seems to be preserved across mammalian evolution. In rodents, grid cells form a location independent coordinate map of multiple length scales to uniquely identify any location the animal visits. By location independent, I mean it is not an absolute position coordinate map - the map is reused in all environments. However, the coordinate map is not just one grid with fixed spacing between grid points. Instead, the coordinate map is composed of multiple grid layers, each with a different length scale between grid points - that is the distance between points on the grid is fixed in each grid layer, but different across layers. For example, one layer may have grid points spaced 30 cms apart and another layer may have grid points spaced 42 cms apart. This scheme enables the location independent coordinate map to generate a unique identification for a location by combining the grid layers - the coactivity of the grid points from the different layers creates a unique combination of coactivity for any location the animal visits - and that is encoded in place cells. Coactivity of grid cells does not imply "spatial intersection"(firing at the same place) of grid cells from different layers, but "temporal intersection"(firing at the same time) of grid cells from the different layers. Source: http://www.quora.com/What-are-the-major-differences-between-grid-cells-and-place-cells
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All the mistakes in the collection of information from website, it’s compilation and communication ( through email ) belongs exclusively to : Vitthalrao B. Khyade (And not to his pace making Shardanagar).
Research Group, A.D.T. And Shardabai Pawar Mahila Mahavidyalaya, Shardanagar, Malegaon(Baramati) Dist. Pune – 413115.
“Dr. APIS” SCIENCE SPECTRUM
Objective: To Establish the Repository of Contributions of Eminent Scholars and Information on Science and Culture For The Society.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fenton's reagent
Fenton's reagent is a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and polychloroethylene (PCE). It was developed in the 1890s by Henry John Horstman Fenton as an analytical reagent.[1]
Iron(II) is oxidized by hydrogen peroxide to iron(III), forming a hydroxyl radical and a hydroxide ion in the process. Iron(III) is then reduced back to iron(II) by another molecule of hydrogen peroxide, forming a hydroperoxyl radical and a proton. The net effect is a disproportionation of hydrogen peroxide to create two different oxygen-radical species, with water (H+ + OH−) as a byproduct.
(1) Fe2+ + H2O2 → Fe3+ + HO• + OH−
(2) Fe3+ + H2O2 → Fe2+ + HOO• + H+
The free radicals generated by this process then engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.[2]
Reaction (1) was suggested by Haber and Weiss in the 1930s as part of what would become the Haber–Weiss reaction.[3] Iron(II) sulfate is typically used as the iron catalyst. The exact mechanisms of the redox cycle are uncertain, and non-OH• oxidizing mechanisms of organic compounds have also been suggested. Therefore, it may be appropriate to broadly discuss Fenton chemistry rather than a specific Fenton reaction.
In the electro-Fenton process, hydrogen peroxide is produced in situ from the electrochemical reduction of oxygen.[4]
Fenton's reagent is also used in organic synthesis for the hydroxylation of arenes in a radical substitution reaction such as the classical conversion of benzene into phenol.
(3) C6H6 + FeSO4 + H2O2 → C6H5OH
A recent hydroxylation example involves the oxidation of barbituric acid to alloxane.[5] Another application of the reagent in organic synthesis is in coupling reactions of alkanes. As an example tert-butanol is dimerized with Fenton's reagent and sulfuric acid to 2,5-dimethyl-2,5-hexanediol.[6]
Biomedical applications
The Fenton reaction has importance in biology because it involves the creation of free radicals by chemicals that are present in vivo. Transition-metal ions such as iron and copper donate or accept free electrons via intracellular reactions and help in creating free radicals. Most intracellular iron is in ferric (+3 ion) form and must be reduced to theferrous (+2) form to take part in Fenton reaction. Since superoxide ions and transition metals act in a synergistic manner in the creation of free radical damage, iron supplementation must not be done in patients with any active infections or in general any diseases.[7]
Henry John Horstman Fenton (18 February 1854 – 13 January 1929) was a British chemist who, in the 1890s invented Fenton's reagent,[1] a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) andtetrachloroethylene (PCE). Born in London, Henry Fenton was educated at Magdalen College School, King's College London and Christ's College, Cambridge.[2] He became the university demonstrator in Chemistry at Cambridge in 1878, and was University Lecturer in Chemistry from 1904 to 1924.
References:
1. Fenton H.J.H. (1894). "Oxidation of tartaric acid in presence of iron". J. Chem. Soc., Trans. 65 (65): 899–911. doi:10.1039/ct8946500899.
2. http://geocleanse.com/fentonsreagent.asp
3. Haber, F. and Weiss, J. (1932). "Über die Katalyse des Hydroperoxydes". Naturwissenschaften 20 (51): 948–950. doi:10.1007/BF0150471.
4. Juan Casado,Jordi Fornaguera,Maria I. Galan (January 2005). "Mineralization of Aromatics in Water by Sunlight-Assisted Electro-Fenton Technology in a Pilot Reactor". Environ. Sci. Technol. 39 (6): 1843–47. doi:10.1021/es0498787. PMID 15819245.
5. Brömme HJ, Mörke W, Peschke E (November 2002). "Transformation of barbituric acid into alloxan by hydroxyl radicals: interaction with melatonin and with other hydroxyl radical scavengers". J. Pineal Res. 33 (4): 239–47. doi:10.1034/j.1600-079X.2002.02936.x. PMID 12390507.
6. E. L. Jenner (1973). "α,α,α',α'-Tetramethyltetramethylene glycol". Org. Synth.; Coll. Vol. 5, p. 1026.
7. Robbins and Cotran (2008). Pathologic Basis of Disease - 7th edition. Elsevier. p. 16. ISBN 9780808923022.
----------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acknowledgement: Girija Girish Tambe of Vaishnavi Xerox helped for Collection of images in the Science Spectrum of 5 September, 2015. All the mistakes in the collection of information from website, it’s compilation and communication belongs exclusively to :
Vitthalrao B. Khyade (And not to his pace making Shardanagar). Please do excuse for the mistakes.
----------------------------------
------------------- [email protected]. -----------------------------------------------------------------------
File: [email protected]
Compiled for: Science Association, Shardabai Pawar Mahila Mahavidyalaya, Shardanagar (Baramati) – 413115 India.
With the Best Compliments From: Shardanagar (The Agro – academic Heritage of Grandsire Padmashri Dr. D. G. Alias Appasaheb Pawar).
All the mistakes in the collection of information from website, it’s compilation and communication ( through email ) belongs exclusively to : Vitthalrao B. Khyade (And not to his pace making Shardanagar).
Research Group, A.D.T. And Shardabai Pawar Mahila Mahavidyalaya, Shardanagar, Malegaon(Baramati) Dist. Pune – 413115.
“Dr. APIS” SCIENCE SPECTRUM
Objective: To Establish the Repository of Contributions of Eminent Scholars and Information on Science and Culture For The Society.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fenton's reagent
Fenton's reagent is a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and polychloroethylene (PCE). It was developed in the 1890s by Henry John Horstman Fenton as an analytical reagent.[1]
Iron(II) is oxidized by hydrogen peroxide to iron(III), forming a hydroxyl radical and a hydroxide ion in the process. Iron(III) is then reduced back to iron(II) by another molecule of hydrogen peroxide, forming a hydroperoxyl radical and a proton. The net effect is a disproportionation of hydrogen peroxide to create two different oxygen-radical species, with water (H+ + OH−) as a byproduct.
(1) Fe2+ + H2O2 → Fe3+ + HO• + OH−
(2) Fe3+ + H2O2 → Fe2+ + HOO• + H+
The free radicals generated by this process then engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.[2]
Reaction (1) was suggested by Haber and Weiss in the 1930s as part of what would become the Haber–Weiss reaction.[3] Iron(II) sulfate is typically used as the iron catalyst. The exact mechanisms of the redox cycle are uncertain, and non-OH• oxidizing mechanisms of organic compounds have also been suggested. Therefore, it may be appropriate to broadly discuss Fenton chemistry rather than a specific Fenton reaction.
In the electro-Fenton process, hydrogen peroxide is produced in situ from the electrochemical reduction of oxygen.[4]
Fenton's reagent is also used in organic synthesis for the hydroxylation of arenes in a radical substitution reaction such as the classical conversion of benzene into phenol.
(3) C6H6 + FeSO4 + H2O2 → C6H5OH
A recent hydroxylation example involves the oxidation of barbituric acid to alloxane.[5] Another application of the reagent in organic synthesis is in coupling reactions of alkanes. As an example tert-butanol is dimerized with Fenton's reagent and sulfuric acid to 2,5-dimethyl-2,5-hexanediol.[6]
Biomedical applications
The Fenton reaction has importance in biology because it involves the creation of free radicals by chemicals that are present in vivo. Transition-metal ions such as iron and copper donate or accept free electrons via intracellular reactions and help in creating free radicals. Most intracellular iron is in ferric (+3 ion) form and must be reduced to theferrous (+2) form to take part in Fenton reaction. Since superoxide ions and transition metals act in a synergistic manner in the creation of free radical damage, iron supplementation must not be done in patients with any active infections or in general any diseases.[7]
Henry John Horstman Fenton (18 February 1854 – 13 January 1929) was a British chemist who, in the 1890s invented Fenton's reagent,[1] a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) andtetrachloroethylene (PCE). Born in London, Henry Fenton was educated at Magdalen College School, King's College London and Christ's College, Cambridge.[2] He became the university demonstrator in Chemistry at Cambridge in 1878, and was University Lecturer in Chemistry from 1904 to 1924.
References:
1. Fenton H.J.H. (1894). "Oxidation of tartaric acid in presence of iron". J. Chem. Soc., Trans. 65 (65): 899–911. doi:10.1039/ct8946500899.
2. http://geocleanse.com/fentonsreagent.asp
3. Haber, F. and Weiss, J. (1932). "Über die Katalyse des Hydroperoxydes". Naturwissenschaften 20 (51): 948–950. doi:10.1007/BF0150471.
4. Juan Casado,Jordi Fornaguera,Maria I. Galan (January 2005). "Mineralization of Aromatics in Water by Sunlight-Assisted Electro-Fenton Technology in a Pilot Reactor". Environ. Sci. Technol. 39 (6): 1843–47. doi:10.1021/es0498787. PMID 15819245.
5. Brömme HJ, Mörke W, Peschke E (November 2002). "Transformation of barbituric acid into alloxan by hydroxyl radicals: interaction with melatonin and with other hydroxyl radical scavengers". J. Pineal Res. 33 (4): 239–47. doi:10.1034/j.1600-079X.2002.02936.x. PMID 12390507.
6. E. L. Jenner (1973). "α,α,α',α'-Tetramethyltetramethylene glycol". Org. Synth.; Coll. Vol. 5, p. 1026.
7. Robbins and Cotran (2008). Pathologic Basis of Disease - 7th edition. Elsevier. p. 16. ISBN 9780808923022.
----------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acknowledgement: Girija Girish Tambe of Vaishnavi Xerox helped for Collection of images in the Science Spectrum of 5 September, 2015. All the mistakes in the collection of information from website, it’s compilation and communication belongs exclusively to :
Vitthalrao B. Khyade (And not to his pace making Shardanagar). Please do excuse for the mistakes.
----------------------------------
------------------- [email protected]. -----------------------------------------------------------------------
File: [email protected]
Compiled for: Science Association, Shardabai Pawar Mahila Mahavidyalaya, Shardanagar (Baramati) – 413115 India.
With the Best Compliments From: Shardanagar (The Agro – academic Heritage of Grandsire Padmashri Dr. D. G. Alias Appasaheb Pawar).
All the mistakes in the collection of information from website, it’s compilation and communication ( through email ) belongs exclusively to : Vitthalrao B. Khyade (And not to his pace making Shardanagar).
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