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🔗 Viruses 🔗 Biology 🔗 Philosophy 🔗 Philosophy/Contemporary philosophy 🔗 History of Science 🔗 Molecular and Cell Biology 🔗 Philosophy/Ethics 🔗 Genetics 🔗 Evolutionary biology 🔗 Science Policy 🔗 Molecular Biology/Molecular and Cell Biology

HeLa (; also Hela or hela) is an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951 from Henrietta Lacks, a patient who died of cancer on October 4, 1951. The cell line was found to be remarkably durable and prolific, which gives rise to its extensive use in scientific research.

The cells from Lacks's cancerous cervical tumor were taken without her knowledge or consent, which was common practice at the time. Cell biologist George Otto Gey found that they could be kept alive, and developed a cell line. Previously, cells cultured from other human cells would only survive for a few days. Scientists would spend more time trying to keep the cells alive than performing actual research on them. Cells from Lacks' tumor behaved differently. As was custom for Gey's lab assistant, she labeled the culture 'HeLa', the first two letters of the patient's first and last name; this became the name of the cell line.

These were the first human cells grown in a lab that were naturally "immortal", meaning that they do not die after a set number of cell divisions (i.e. cellular senescence). These cells could be used for conducting a multitude of medical experiments—if the cells died, they could simply be discarded and the experiment attempted again on fresh cells from the culture. This represented an enormous boon to medical and biological research, as previously stocks of living cells were limited and took significant effort to culture.

The stable growth of HeLa enabled a researcher at the University of Minnesota hospital to successfully grow polio virus, enabling the development of a vaccine, and by 1952, Jonas Salk developed a vaccine for polio using these cells. To test Salk's new vaccine, the cells were put into mass production in the first-ever cell production factory.

In 1953, HeLa cells were the first human cells successfully cloned and demand for the HeLa cells quickly grew in the nascent biomedical industry. Since the cells' first mass replications, they have been used by scientists in various types of investigations including disease research, gene mapping, effects of toxic substances on organisms, and radiation on humans. Additionally, HeLa cells have been used to test human sensitivity to tape, glue, cosmetics, and many other products.

Scientists have grown an estimated 50 million metric tons of HeLa cells, and there are almost 11,000 patents involving these cells.

The HeLa cell lines are also notorious for invading other cell cultures in laboratory settings. Some have estimated that HeLa cells have contaminated 10–20% of all cell lines currently in use.

🔗 Biography 🔗 Climate change 🔗 Environment 🔗 Biography/science and academia 🔗 Energy

James Ephraim Lovelock (26 July 1919 – 26 July 2022) was a British independent scientist, environmentalist and futurist. He was best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating system.

With a PhD in medicine, Lovelock began his career performing cryopreservation experiments on rodents, including successfully thawing frozen specimens. His methods were influential in the theories of cryonics (the cryopreservation of humans). He invented the electron capture detector, and using it, became the first to detect the widespread presence of chlorofluorocarbons in the atmosphere. While designing scientific instruments for NASA, he developed the Gaia hypothesis.

In the 2000s, he proposed a method of climate engineering to restore carbon dioxide–consuming algae. He was an outspoken member of Environmentalists for Nuclear, asserting that fossil fuel interests have been behind opposition to nuclear energy, citing the effects of carbon dioxide as being harmful to the environment, and warning of global warming due to the greenhouse effect. He authored several environmental science books based upon the Gaia hypothesis from the late 1970s.

🔗 Disambiguation

Doom may refer to:

🔗 Human rights 🔗 Mass surveillance 🔗 History 🔗 Crime 🔗 Death 🔗 China 🔗 Philosophy 🔗 Politics 🔗 Philosophy/Social and political philosophy 🔗 Islam 🔗 Central Asia 🔗 Anthropology 🔗 Sociology 🔗 Discrimination 🔗 Philosophy/Ethics 🔗 Ethnic groups 🔗 History/Contemporary History 🔗 China/Chinese politics

The Uyghur genocide is the ongoing series of human rights abuses perpetrated by the government of China against the Uyghur people and other ethnic and religious minorities in and around the Xinjiang Uygur Autonomous Region (XUAR) of the People's Republic of China. Since 2014, the Chinese government, under the direction of the Chinese Communist Party (CCP) during the administration of CCP general secretary Xi Jinping, has pursued policies leading to more than one million Muslims (the majority of them Uyghurs) being held in secretive internment camps without any legal process in what has become the largest-scale and most systematic detention of ethnic and religious minorities since the Holocaust and World War II. Thousands of mosques have been destroyed or damaged, and hundreds of thousands of children have been forcibly separated from their parents and sent to boarding schools.

These policies have been described by critics as the forced assimilation of Xinjiang, as well as an ethnocide or cultural genocide. Some governments, activists, independent NGOs, human rights experts, academics, government officials, and the East Turkistan Government-in-Exile have called it a genocide.

In particular, critics have highlighted the concentration of Uyghurs in state-sponsored internment camps, suppression of Uyghur religious practices, political indoctrination, severe ill-treatment, as well as extensive evidence and other testimonials detailing human rights abuses including forced sterilization, contraception, abortion, and infanticides. Chinese government statistics show that from 2015 to 2018, birth rates in the mostly Uyghur regions of Hotan and Kashgar fell by more than 60%. In the same period, the birth rate of the whole country decreased by 9.69%, from 12.07 to 10.9 per 1,000 people. Chinese authorities acknowledged that birth rates dropped by almost a third in 2018 in Xinjiang, but denied reports of forced sterilization and genocide. Birth rates fell nearly 24% in 2019 (compared to a nationwide decrease of just 4.2%).

International reactions have been sharply divided, with dozens of United Nations (UN) member states issuing opposing letters to the United Nations Human Rights Council in support and condemnation of China's policies in Xinjiang in 2020. In December 2020, the International Criminal Court declined to take investigative action against China on the basis of not having jurisdiction over China for most of the alleged crimes. The United States was the first country to declare the human rights abuses a genocide, announcing its determination on January 19, 2021, although the US State Department's Office of the Legal Adviser concluded that there was insufficient evidence to prove genocide. This was followed by Canada's House of Commons and the Dutch parliament each passing a non-binding motion in February 2021 to recognize China's actions as genocide. Later, in April 2021, the United Kingdom's House of Commons unanimously passed a non-binding motion to recognize the actions as genocide. In May 2021 the New Zealand parliament unanimously declared that "severe human rights abuses" were occurring against the Uyghur people in China and the Seimas of Lithuania passed a resolution that recognized the Chinese government's abuse of the Uyghurs as a genocide.

🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Numismatics 🔗 Numismatics/Cryptocurrency

Hashcash is a proof-of-work system used to limit email spam and denial-of-service attacks, and more recently has become known for its use in bitcoin (and other cryptocurrencies) as part of the mining algorithm. Hashcash was proposed in 1997 by Adam Back and described more formally in Back's 2002 paper "Hashcash - A Denial of Service Counter-Measure".

Welcome to WikiProject AI Cleanup—a collaboration to combat the increasing problem of unsourced, poorly written AI-generated content on Wikipedia. If you would like to help, add yourself as a participant in the project, inquire on the talk page, and see the to-do list.

🔗 Physics 🔗 Physics/relativity 🔗 Chemistry

Relativistic quantum chemistry combines relativistic mechanics with quantum chemistry to explain elemental properties and structure, especially for the heavier elements of the periodic table. A prominent example of such an explanation is the color of gold: due to relativistic effects, it is not silvery like most other metals.

The term relativistic effects was developed in light of the history of quantum mechanics. Initially quantum mechanics was developed without considering the theory of relativity. Relativistic effects are those discrepancies between values calculated by models that consider and that do not consider relativity. Relativistic effects are important for the heavier elements with high atomic numbers. In the most common layout of the periodic table, these elements are shown in the lower area. Examples are the lanthanides and actinides.

Relativistic effects in chemistry can be considered to be perturbations, or small corrections, to the non-relativistic theory of chemistry, which is developed from the solutions of the Schrödinger equation. These corrections affect the electrons differently depending on the electron speed relative to the speed of light. Relativistic effects are more prominent in heavy elements because only in these elements do electrons attain sufficient speeds for the elements to have properties that differ from what non-relativistic chemistry predicts.

🔗 Biography 🔗 History 🔗 Death 🔗 Lists

This is a list of unusual deaths. This list includes only unique or extremely rare circumstances of death recorded throughout history, noted as being unusual by multiple sources. Oxford Dictionaries defines the word unusual as "not habitually or commonly occurring or done" and "remarkable or interesting because different from or better than others".

🔗 Books 🔗 Poland

The Scottish Book (Polish: Księga Szkocka) was a thick notebook used by mathematicians of the Lwów School of Mathematics in Poland for jotting down problems meant to be solved. The notebook was named after the "Scottish Café" where it was kept.

Originally, the mathematicians who gathered at the cafe would write down the problems and equations directly on the cafe's marble table tops, but these would be erased at the end of each day, and so the record of the preceding discussions would be lost. The idea for the book was most likely originally suggested by Stefan Banach, or his wife, Łucja, who purchased a large notebook and left it with the proprietor of the cafe.

🔗 Horticulture and Gardening 🔗 Animals 🔗 Sanitation

The nematodes ( NEM-ə-tohdz or NEEM-; Greek: Νηματώδη; Latin: Nematoda) roundworms or eelworms, constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms, but there are many that are parasitic. The parasitic worms (helminths) are the cause of soil-transmitted helminthiases.

They are taxonomically classified along with arthropods, tardigrades and other moulting animals in the clade Ecdysozoa. Unlike the vaguely similar flatworms, nematodes have a tubular digestive system, with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum.

Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species are uncertain. A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts this figure at over 25,000. Estimates of the total number of extant species are subject to even greater variation. A widely referenced article published in 1993 estimated there may be over 1 million species of nematode. A subsequent publication challenged this claim, estimating the figure to be at least 40,000 species. Although the highest estimates (up to 100 million species) have since been deprecated, estimates supported by rarefaction curves, together with the use of DNA barcoding and the increasing acknowledgment of widespread cryptic species among nematodes, have placed the figure closer to 1 million species.

Nematodes have successfully adapted to nearly every ecosystem: from marine (salt) to fresh water, soils, from the polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations as diverse as mountains, deserts, and oceanic trenches. They are found in every part of the earth's lithosphere, even at great depths, 0.9–3.6 km (3,000–12,000 ft) below the surface of the Earth in gold mines in South Africa. They represent 90% of all animals on the ocean floor. In total, 4.4 × 10²⁰ nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests. Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems. They have been shown to play crucial roles in polar ecosystems. The roughly 2,271 genera are placed in 256 families. The many parasitic forms include pathogens in most plants and animals. A third of the genera occur as parasites of vertebrates; about 35 nematode species occur in humans.

Nathan Cobb, a nematologist, described the ubiquity of nematodes on Earth thus:

In short, if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable since, for every massing of human beings, there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites.^(p 472)