User:Leogirrrl/sandbox

JANET HAYNES Living organisms can produce magnetite . In humans, magnetite can be found in various parts of the brain including the frontal, parietal, occipital, and temporal lobes, brainstem, cerebellum and basal ganglia. Iron can be found in three forms in the brain – magnetite, hemoglobin (blood) and ferritin (protein), and areas of the brain related to motor function generally contain more iron .

Magnetite can be found in the hippocampus. The hippocampus is associated with information processing, specifically learning and memory . However, magnetite can have toxic effects due to its charge or magnetic nature and its involvement in oxidative stress or the production of free radicals . Research suggests that beta-amyloid plaques and tau proteins associated with neurodegenerative disease frequently occur after oxidative stress and the build-up of iron

Some researchers also suggest that humans possess a magnetic sense, proposing that this could allow certain people to use magnetoreception for navigation. The role of magnetite in the brain is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism.

Electron microscope scans of human brain-tissue samples are able to differentiate between magnetite produced by the body's own cells and magnetite absorbed from airborne pollution, the natural forms being jagged and crystalline, while magnetite pollution occurs as rounded nanoparticles. Potentially a human health hazard, airborne magnetite is a result of pollution specifically combustion. These nanoparticles can travel to the brain via the olfactory nerve [3] increasing the concentration of magnetite in the brain . In some brain samples, the nanoparticle pollution outnumbers the natural particles by as much as 100:1, and such pollution-borne magnetite particles may be linked to abnormal neural deterioration.

In one study, the characteristic nanoparticles were found in the brains of 37 people: 29 of these, aged 3 to 85, had lived and died in Mexico City, a significant air pollution hotspot. A further eight, aged 62 to 92, came from Manchester, and some had died with varying severities of neurodegenerative diseases. According to researchers led by Prof. Barbara Maher at Lancaster University and published in the Proceedings of the National Academy of Sciences, such particles could conceivably contribute to diseases like Alzheimer's disease. Though a causal link has not been established, laboratory studies suggest that iron oxides like magnetite are a component of protein plaques in the brain, linked to Alzheimer's disease. Increased iron levels, specifically magnetic iron, have been found portions of the brain in Alzheimer's patients . Monitoring changes in iron concentrations may make it possible to detect the loss of neurons and the development of neurodegenerative diseases prior to the onset of symptoms due to the relationship between magnetite and ferritin In tissue, magnetite and ferritin can produce small magnetic fields which will interact with magnetic resonance imaging (MRI) creating contrast Huntington patients have not shown increased magnetite levels; however, high levels have been found in study mice

Magnetite

User:MCarrier18/sandbox

User:Carleton2712/sandbox

The section of Magnetite Janet will be editing is ″Biological occurrences″, specifically, the ″Human Brain″.

In this section, there is limited information on magnetite (naturally occurring or pollution based), its role and distribution in the human brain, its relationship to memory and Alzheimer's disease, its influence on the development of plaques, and its potential for use as a measurable precursor or diagnostic tool. Additionally, there is no information provided on magnetite's link to two other neurodegenerative diseases - Parkinson's and Huntington's diseases.

Currently, the information provided on the connection between magnetite and Alzheimer's disease relies on only one source; potentially creating a bias.

The proposed edits will expand, clarify and restructure the existing information addressing the items identified above. By expanding this section to include reliable information from a variety of sources, I will be reducing the likelihood of biased information and address the current information gap. The new information should provide a clear link between magnetite, various brain structures and neurodegenerative diseases. Finally, the additional information will be divided into paragraphs with subheadings, as appropriate, to provide structure and improve readability and will be written in plain language to assist with understanding.

Potential References

Investigation on positive correlation of increased brain iron deposition with cognitive impairment in Alzheimer disease by using quantitative MR R2′ mapping - https://link-springer-com.proxy.library.carleton.ca/article/10.1007%2Fs11596-011-0493-1

Increased levels of magnetic iron compounds in Alzheimer's disease - https://www.ncbi.nlm.nih.gov/pubmed/18334756?access_num=18334756&link_type=MED&dopt=Abstract

Magnetite pollution nanoparticles in the human brain - http://www.pnas.org/content/pnas/early/2016/08/31/1605941113.full.pdf

Magnetite biomineralization in the human brain - http://www.pnas.org/content/89/16/7683 Iron, brain ageing and neurodegenerative disorders - https://www-nature-com.proxy.library.carleton.ca/articles/nrn1537

Iron accumulation in Alzheimer disease is a source of redox-generated free radicals - http://www.pnas.org.proxy.library.carleton.ca/content/94/18/9866.short

High-field magnetic resonance imaging of brain iron: birth of a biomarker? -http://onlinelibrary.wiley.com.proxy.library.carleton.ca/doi/10.1002/nbm.922/abstract;jsessionid=0F60859A5BADF2652F6ECF7E8D37BA40.f02t02

MRI assessment of basal ganglia iron deposition in Parkinson's disease - http://onlinelibrary.wiley.com.proxy.library.carleton.ca/doi/10.1002/jmri.21563/full

Cytotoxicity and proliferative capacity impairment induced on human brain cell cultures after short- and long-term exposure to magnetite nanoparticles - http://onlinelibrary.wiley.com.proxy.library.carleton.ca/doi/10.1002/jat.3367/full

In vitro study of magnetite-amyloid β complex formation - https://journals-scholarsportal-info.proxy.library.carleton.ca/pdf/15499634/v08i0006/974_ivsomcf.xml

Magnetite Minerals in the Human Brain: What is their role? - https://link.springer.com/chapter/10.1007/978-94-007-4372-4_6

Alzheimer's Disease: What is the Connection between Amyloid Plaques, Magnetite and Memory? - https://www.omicsonline.org/open-access/alzheimers-disease-what-is-the-connection-between-amyloid-plaquesmagnetite-and-memory-2161-0460-1000366.pdf

Magnetite Nano-Particles in Information Processing: From the Bacteria to the Human Brain Neocortex - ISBN: 9781-61761-839-0

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Article Evaluation Wiki page - Peridot https://en.wikipedia.org/wiki/Peridot

General The material in the article is relevant; however, it is also very limited. The Flag indicates lead section does not provide a full description.

Body

In the Occurrence section, the following could be expanded using the identified sources:

- Expand St. John's Island information

    - ZABARGAD: THE ANCIENT PERIDOT ISLAND IN THE RED SEA - https://www.gia.edu/doc/Spring-1981-Gems-Gemology-Zabargad-Peridot-Island-Red-Sea.pdf

- Expand principle source

    - Peridot from the Central Highlands of Vietnam: Properties, Origin, and Formation - https://www.gia.edu/gems-gemology/fall-2016-peridot-central-highlands-vietnam-properties-origin-formation
    - THE GEMOLOGICAL CHARACTERISTICS OF CHINESE PERIDOT - https://www.gia.edu/doc/SP86.pdf#page=41

- Expand in meteorites

    - Identification_of_Extraterrestrial_Peridot_by_Trace_Elements - https://www.researchgate.net/publication/285720827_Identification_of_Extraterrestrial_Peridot_by_Trace_Elements

The Gemology section could be expanded using the following source to specifically address the peridot/emeralds confusion:

    - Gem minerals in early Arabic literature - http://go.galegroup.com.proxy.library.carleton.ca/ps/i.do?p=AONE&u=ocul_carleton&id=GALE%7CA17339989&v=2.1&it=r&sid=summon&authCount=1

Citations 3rd reference does not appear to work. 5th reference does not appear to be linked. 6th reference requires a page reference. Additionally, references/citings appear to be missing.

Talk Page The Talk page generally refers to the pronunciation of peridot and adds little to the webpage.

History Page The History page generally refers to many reverted edits and changes attributed to vandalism.

To better align the webpage with the material taught in class, a variety of aspects or links related to mining gemstones/resources should be added such as reserve/resource, feasibility studies, core samples, drilling, financing, extraction/production and reporting. None of these aspects were specifically discussed on the peridot page.

Mike's Stuff

Formation processes of magnetite

I am interested in determining the various processes in which magnetite forms

Draft

Magnetite contains both ferrous and ferric iron, requiring environments containing intermediate levels of available oxygen to form.

Hydrothermal processes

Magnetite ore deposits found within sedimentary rock are formed formed within banded iron formations (BIF). BIFs can take one of two forms, the first called the Algoma-type occurs in volcanic rock dominated with greenstone belts, and involves the chemical precipitation of Iron in anoxic environments and often associated with volcanic rock.

When oxidized the iron would precipitate out and accumulate at the bottom of the seafloor, as the oxygen levels continuously shift, we can see deposits interlaced layers of iron and silicate form.

Superior type are the second form of BIFs occurring on continental shelves and can be found around the world. Superior types are formed by chemical precipitation in shallow waters, during the Paleoproterozoic era, and due to the low atmospheric and ocean oxygen levels, resulting in high iron levels in the oceans. Under calm shallow conditions, oxygen released during photosynthesis by blue-green algae, would combine with the iron creating magnetite, which would then sink and deposit on the floor. Unaltered BIFs magentite formation was dependent of the the oxygen fugacity of the surrounding rock.

Magmatic processes

Magmatic segregation is any process in which elements become concentrated while the magma is cooling and crystallizing. Magnetite can also form by magmatic processes resulting in cumulus magnetite, however this posses as a poor source of iron ore, rather is a valuable source of vanadium due to the deposits chemical composition.

Connor's stuff

Original in wikipedia

Magnetite is sometimes found in large quantities in beach sand. Such black sands (mineral sands or iron sands) are found in various places, such as Lung Kwu Tan of Hong Kong; California, United States; and the west coast of the North Island of New Zealand.^[13] The magnetite, eroded from rocks, is carried to the beach by rivers and concentrated by wave action and currents. Huge deposits have been found in banded iron formations. These sedimentary rocks have been used to infer changes in the oxygen content of the atmosphere of the Earth.^[14]

Large deposits of magnetite are also found in the Atacama region of Chile; the Valentines region of Uruguay; Kiruna, Sweden; the Pilbara, Midwest and Northern Goldfields regions in Western Australia; the Eyre Peninsula in South Australia; the Tallawang Region of New South Wales; and in the Adirondack region of New York in the United States. Kediet ej Jill, the highest mountain of Mauritania, is made entirely of the mineral. Deposits are also found in Norway, Germany, Italy, Switzerland, South Africa, India, Indonesia, Mexico, Hong Kong, and in Oregon, New Jersey, Pennsylvania, North Carolina, West Virginia, Virginia, New Mexico, Utah, and Colorado in the United States. In 2005, an exploration company, Cardero Resources, discovered a vast deposit of magnetite-bearing sand dunes in Peru. The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. The sand contains 10% magnetite.^[15]

Magnetite crystals with a cubic habit have been found in just one location: Balmat, St. Lawrence County, New York.^[16

Rough draft edits and additions

Magnetite appears in a variety of different geological environments and is a very widespread iron oxide mineral. As magnetite is formed it aligns itself with the earth’s magnetic field at the time of formation and does not change. This is called paleomagnitism and shows a record of the earth’s magnetic field when the magnetite was formed and can show changes in the earth’s magnetic field and polarity through time (Source- https://www.esci.umn.edu/courses/1001/minerals/magnetite.shtml). If magnetite is in a large enough quantity it can be found in aeromagnetic surveys using a magnetometer which measures magnetic intensities (Source- http://www.australianminesatlas.gov.au/education/down_under/exploration/magsurv.html).

Magnetite is sometimes found in large quantities in beach sand. Such black sands (mineral sands or iron sands) are found in various places, such as Lung Kwu Tan of Hong Kong; California, United States; and the west coast of the North Island of New Zealand.^[13] The magnetite, eroded from rocks, is carried to the beach by rivers and concentrated by wave action and currents. Huge deposits have been found in banded iron formations. These sedimentary rocks have been used to infer changes in the oxygen content of the atmosphere of the Earth.^[14]

Remote sensing has the potential to be a big part in locating magnetite sands as even small amounts of magnetite in sand can drastically alter the sands albedo which is the amount of electromagnetic radiation the sand will reflect. The darker magnetite will lower the sands albedo compared to sands that do not contain magnetite (Source- https://books.google.ca/books?hl=en&lr=&id=lERADwAAQBAJ&oi=fnd&pg=PR9&dq=magnetite+remote+sensing&ots=p3_swyw5_1&sig=NZIYVxtxpY3JKDPdNLepexNZfzg#v=onepage&q=magnetite&f=false).

Large deposits of magnetite are also found in the Atacama region of Chile; the Valentines region of Uruguay; Kiruna, Sweden; the Pilbara, Midwest and Northern Goldfields regions in Western Australia; the Eyre Peninsula in South Australia; the Tallawang Region of New South Wales; and in the Adirondack region of New York in the United States. Kediet ej Jill, the highest mountain of Mauritania, is made entirely of the mineral. Deposits are also found in Norway, Germany, Italy, Switzerland, South Africa, India, Indonesia, Mexico, Hong Kong, and in Oregon, New Jersey, Pennsylvania, North Carolina, West Virginia, Virginia, New Mexico, Utah, and Colorado in the United States. In 2005, an exploration company, Cardero Resources, discovered a vast deposit of magnetite-bearing sand dunes in Peru. The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. The sand contains 10% magnetite.^[15]

In large enough quantities magnetite can affect compass navigation. In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Extra steps and repeated observations are required when using a compass in Tasmania to keep navigation problems to the minimum (Source- https://eprints.utas.edu.au/13644/1/1997_Leaman_Magnetic_rst.pdf).

Magnetite crystals with a cubic habit have been found in just one location: Balmat, St. Lawrence County, New York.^[16

Magnetite can also be found in fossils due to biomineralization and are referred to as magnetofossils (Source- http://web.gps.caltech.edu/~jkirschvink/pdfs/AnnualReviews89.pdf). There are also instances of magnetite with origins in space coming from meteorites (Source- http://www.pnas.org/content/pnas/99/10/6556.full.pdf).