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Monday, May 25, 2020

Andrei Sakharov

From Wikipedia, the free encyclopedia

Andrei Sakharov
RIAN archive 25981 Academician Sakharov.jpg
Sakharov at a conference of the USSR Academy of Sciences on 1 March 1989
Born21 May 1921
Died14 December 1989 (aged 68)
Moscow, Russian SFSR, Soviet Union
CitizenshipSoviet
Alma mater
Known for
Spouse(s)Klavdia Alekseyevna Vikhireva (1943–1969; her death)
Yelena Bonner (1972–1989; his death)
Awards
Scientific career
FieldsNuclear physics, physical cosmology

Andrei Dmitrievich Sakharov (Russian: Андре́й Дми́триевич Са́харов; 21 May 1921 – 14 December 1989) was a Russian nuclear physicist, dissident, Nobel laureate, and activist for disarmament, peace and human rights.

He became renowned as the designer of the Soviet Union's RDS-37, a codename for Soviet development of thermonuclear weapons. Sakharov later became an advocate of civil liberties and civil reforms in the Soviet Union, for which he faced state persecution; these efforts earned him the Nobel Peace Prize in 1975. The Sakharov Prize, which is awarded annually by the European Parliament for people and organizations dedicated to human rights and freedoms, is named in his honor.

Biography

Sakharov was born in Moscow on May 21, 1921. His father was Dmitri Ivanovich Sakharov, a private school physics teacher and an amateur pianist. His father later taught at the Second Moscow State University. Andrei's grandfather Ivan had been a prominent lawyer in the Russian Empire who had displayed respect for social awareness and humanitarian principles (including advocating the abolition of capital punishment) that would later influence his grandson. Sakharov's mother was Yekaterina Alekseyevna Sakharova, a great-granddaughter of the prominent military commander Alexey Semenovich Sofiano (who was of Greek ancestry). Sakharov's parents and paternal grandmother, Maria Petrovna, largely shaped his personality. His mother and grandmother were churchgoers; his father was a nonbeliever. When Andrei was about thirteen, he realized that he did not believe. However, despite being an atheist, he did believe in a "guiding principle" that transcends the physical laws.

Education and career

Sakharov entered Moscow State University in 1938. Following evacuation in 1941 during the Great Patriotic War (World War II), he graduated in Aşgabat, in today's Turkmenistan. He was then assigned to laboratory work in Ulyanovsk. In 1943, he married Klavdia Alekseyevna Vikhireva, with whom he raised two daughters and a son. Klavdia would later die in 1969. He returned to Moscow in 1945 to study at the Theoretical Department of FIAN (the Physical Institute of the Soviet Academy of Sciences). He received his Ph.D. in 1947.

Development of thermonuclear devices

After World War II, he researched cosmic rays. In mid-1948 he participated in the Soviet atomic bomb project under Igor Kurchatov and Igor Tamm. Sakharov's study group at FIAN in 1948 came up with a second concept in August–September 1948. Adding a shell of natural, unenriched uranium around the deuterium would increase the deuterium concentration at the uranium-deuterium boundary and the overall yield of the device, because the natural uranium would capture neutrons and itself fission as part of the thermonuclear reaction. This idea of a layered fission-fusion-fission bomb led Sakharov to call it the sloika, or layered cake. The first Soviet atomic device was tested on August 29, 1949. After moving to Sarov in 1950, Sakharov played a key role in the development of the first megaton-range Soviet hydrogen bomb using a design known as Sakharov's Third Idea in Russia and the Teller–Ulam design in the United States. Before his Third Idea, Sakharov tried a "layer cake" of alternating layers of fission and fusion fuel. The results were disappointing, yielding no more than a typical fission bomb. However the design was seen to be worth pursuing because deuterium is abundant and uranium is scarce, and he had no idea how powerful the US design was. Sakharov realised that in order to cause the explosion of one side of the fuel to symmetrically compress the fusion fuel, a mirror could be used to reflect the radiation. The details had not been officially declassified in Russia when Sakharov was writing his memoirs, but in the Teller–Ulam design, soft X-rays emitted by the fission bomb were focused onto a cylinder of lithium deuteride to compress it symmetrically. This is called radiation implosion. The Teller–Ulam design also had a secondary fission device inside the fusion cylinder to assist with the compression of the fusion fuel and generate neutrons to convert some of the lithium to tritium, producing a mixture of deuterium and tritium. Sakharov's idea was first tested as RDS-37 in 1955. A larger variation of the same design which Sakharov worked on was the 50 Mt Tsar Bomba of October 1961, which was the most powerful nuclear device ever detonated.

Sakharov saw "striking parallels" between his fate and those of J. Robert Oppenheimer and Edward Teller in the US. Sakharov believed that in this "tragic confrontation of two outstanding people", both deserved respect, because "each of them was certain he had right on his side and was morally obligated to go to the end in the name of truth." While Sakharov strongly disagreed with Teller over nuclear testing in the atmosphere and the Strategic Defense Initiative, he believed that American academics had been unfair to Teller's resolve to get the H-bomb for the United States since "all steps by the Americans of a temporary or permanent rejection of developing thermonuclear weapons would have been seen either as a clever feint, or as the manifestation of stupidity. In both cases, the reaction would have been the same – avoid the trap and immediately take advantage of the enemy's stupidity."
Sakharov never felt that by creating nuclear weapons he had "known sin", in Oppenheimer's expression. He later wrote:
After more than forty years, we have had no third world war, and the balance of nuclear terror ... may have helped to prevent one. But I am not at all sure of this; back then, in those long-gone years, the question didn't even arise. What most troubles me now is the instability of the balance, the extreme peril of the current situation, the appalling waste of the arms race ... Each of us has a responsibility to think about this in global terms, with tolerance, trust, and candor, free from ideological dogmatism, parochial interests, or national egotism."
— Andrei Sakharov

Support for peaceful use of nuclear technology

In 1950 he proposed an idea for a controlled nuclear fusion reactor, the tokamak, which is still the basis for the majority of work in the area. Sakharov, in association with Tamm, proposed confining extremely hot ionized plasma by torus shaped magnetic fields for controlling thermonuclear fusion that led to the development of the tokamak device.

Magneto-implosive generators

In 1951 he invented and tested the first explosively pumped flux compression generators, compressing magnetic fields by explosives. He called these devices MK (for MagnetoKumulative) generators. The radial MK-1 produced a pulsed magnetic field of 25 megagauss (2500 teslas). The resulting helical MK-2 generated 1000 million amperes in 1953.

Sakharov then tested a MK-driven "plasma cannon" where a small aluminum ring was vaporized by huge eddy currents into a stable, self-confined toroidal plasmoid and was accelerated to 100 km/s. Sakharov later suggested replacing the copper coil in MK generators with a large superconductor solenoid to magnetically compress and focus underground nuclear explosions into a shaped charge effect. He theorized this could focus 1023 protons per second on a 1 mm2 surface.

Particle physics and cosmology

After 1965 Sakharov returned to fundamental science and began working on particle physics and physical cosmology.

2D didactic image of Sakharov's model of the universe with reversal of the arrow of time

He tried to explain the baryon asymmetry of the universe; in that regard, he was the first to propose proton decay and to consider CPT-symmetric events occurring before the Big Bang:
We can visualize that neutral spinless maximons (or photons) are produced at ''t'' < 0 from contracting matter having an excess of antiquarks, that they pass "one through the other" at the instant ''t'' = 0 when the density is infinite, and decay with an excess of quarks when ''t'' > 0, realizing total CPT symmetry of the universe. All the phenomena at t < 0 are assumed in this hypothesis to be CPT reflections of the phenomena at t > 0.
His legacy in this domain are the famous conditions named after him: Baryon number violation, C-symmetry and CP-symmetry violation, and interactions out of thermal equilibrium.

Sakharov was also interested in explaining why the curvature of the universe is so small. This lead him to consider cyclic models, where the universe oscillates between contraction and expansion phases. In those models, after a certain number of cycles the curvature naturally becomes infinite even if it had not started this way: Sakharov considered three starting points, a flat universe with a slightly negative cosmological constant, a universe with a positive curvature and a zero cosmological constant, and a universe with a negative curvature and a slightly negative cosmological constant. Those last two models feature what Sakharov calls a reversal of the time arrow, which can be summarised as follow. He considers times t > 0 after the initial Big Bang singularity at t = 0 (which he calls "Friedman singularity" and denotes Φ) as well as times t < 0 before that singularity. He then assumes that entropy increases when time increases for t > 0 as well as when time decreases for t < 0, which constitutes his reversal of time. Then he considers the case when the universe at t < 0 is the image of the universe at t > 0 under CPT symmetry but also the case when it is not so: the universe has a non-zero CPT charge at t = 0 in this case. Sakharov considers a variant of this model where the reversal of the time arrow occurs at a point of maximum entropy instead of happening at the singularity. In those models there is no dynamic interaction between the universe at t < 0 and t > 0.

In his first model the two universes did not interact, except via local matter accumulation whose density and pressure become high enough to connect the two sheets through a bridge without spacetime between them, but with a continuity of geodesics beyond the Schwarzschild radius with no singularity, allowing an exchange of matter between the two conjugated sheets, based on an idea after Igor Dmitriyevich Novikov. Novikov called such singularities a collapse and an anticollapse, which are an alternative to the couple black hole and white hole in the wormhole model. Sakharov also proposed the idea of induced gravity as an alternative theory of quantum gravity.

Turn to activism

Since the late 1950s Sakharov had become concerned about the moral and political implications of his work. Politically active during the 1960s, Sakharov was against nuclear proliferation. Pushing for the end of atmospheric tests, he played a role in the 1963 Partial Test Ban Treaty, signed in Moscow.

Sakharov was also involved in an event with political consequences in 1964, when the USSR Academy of Sciences nominated for full membership Nikolai Nuzhdin, a follower of Trofim Lysenko (initiator of the Stalin-supported anti-genetics campaign Lysenkoism). Contrary to normal practice Sakharov, a member of the Academy, publicly spoke out against full membership for Nuzhdin, holding him responsible for "the defamation, firing, arrest, even death, of many genuine scientists." In the end, Nuzhdin was not elected, but the episode prompted Sergei Khrushchev to order the KGB to gather compromising material on Sakharov.

The major turn in Sakharov's political evolution came in 1967, when anti-ballistic missile defense became a key issue in US–Soviet relations. In a secret detailed letter to the Soviet leadership of July 21, 1967, Sakharov explained the need to "take the Americans at their word" and accept their proposal for a "bilateral rejection by the USA and the Soviet Union of the development of antiballistic missile defense", because otherwise an arms race in this new technology would increase the likelihood of nuclear war. He also asked permission to publish his manuscript (which accompanied the letter) in a newspaper to explain the dangers posed by this kind of defense. The government ignored his letter and refused to let him initiate a public discussion of ABMs in the Soviet press.

In May 1968 Sakharov completed an essay entitled "Reflections on Progress, Peaceful Coexistence, and Intellectual Freedom". In it, he described the anti-ballistic missile defense as a major threat of world nuclear war. After this essay was circulated in samizdat and then published outside the Soviet Union, Sakharov was banned from conducting any military-related research and returned to FIAN to study fundamental theoretical physics.

Over the next twelve years, until his exile to Gorky (Nizhny Novgorod) in January 1980, Andrei Sakharov assumed the role of a widely recognized and open dissident in Moscow. He stood vigil outside closed courtrooms, wrote appeals on behalf of more than two hundred individual prisoners, and continued to write essays about the need for democratization.

In 1970 Sakharov was among the three founding members of the Committee on Human Rights in the USSR along with Valery Chalidze and Andrei Tverdokhlebov. The Committee wrote appeals, collected signatures for petitions and succeeded in affiliating with several international human rights organizations. Its work was the subject of many KGB reports and brought Sakharov under increasing pressure from the government.

Sakharov married a fellow human rights activist, Yelena Bonner, in 1972.

By 1973 Sakharov was meeting regularly with Western correspondents, holding press conferences in his apartment. He appealed to the U.S. Congress to approve the 1974 Jackson-Vanik Amendment to a trade bill, which coupled trade tariffs to the Kremlin's willingness to allow freer emigration.

Attacked by Soviet establishment, 1972 onwards

Sakharov with Naum Meiman, Sofiya Kallistratova, Petro Grigorenko, his wife Zinaida Grigorenko, Tatyana Velikanova's mother, the priest Father Sergei Zheludkov; in the lower row are Genrikh Altunyan and Alexander Podrabinek. Photo taken on 16 October 1977.
In 1972 Sakharov became the target of sustained pressure from his fellow scientists in the USSR Academy of Sciences, the Soviet press. The writer Aleksandr Solzhenitsyn, sprang to his defence.

In 1973 and 1974, the Soviet media campaign continued, targeting both Sakharov and Solzhenitsyn. While Sakharov disagreed with Solzhenitsyn's vision of Russian revival, he deeply respected him for his courage.

Sakharov later described that it took "years" for him to "understand how much substitution, deceit, and lack of correspondence with reality there was" in the Soviet ideals. "At first I thought, despite everything that I saw with my own eyes, that the Soviet State was a breakthrough into the future, a kind of prototype for all countries". Then he came, in his words, to "the theory of symmetry: all governments and regimes to a first approximation are bad, all peoples are oppressed, and all are threatened by common dangers."

After that he realized that there is not much
"symmetry between a cancer cell and a normal one. Yet our state is similar to a cancer cell – with its messianism and expansionism, its totalitarian suppression of dissent, the authoritarian structure of power, with a total absence of public control in the most important decisions in domestic and foreign policy, a closed society that does not inform its citizens of anything substantial, closed to the outside world, without freedom of travel or the exchange of information." 
Sakharov's ideas on social development led him to put forward the principle of human rights as a new basis of all politics. In his works he declared that "the principle 'what is not prohibited is allowed' should be understood literally", defying what he saw as unwritten ideological rules imposed by the Communist party on the society in spite of a democratic (1936) USSR Constitution

In no way did Sakharov consider himself a prophet or the like:
"I am no volunteer priest of the idea, but simply a man with an unusual fate. I am against all kinds of self-immolation (for myself and for others, including the people closest to me)."
In a letter written from exile, he cheered up a fellow physicist and human rights activist with the words: "Fortunately, the future is unpredictable and also – because of quantum effects – uncertain." For Sakharov the indeterminacy of the future supported his belief that he could, and should, take personal responsibility for it.

Nobel Peace Prize (1975)

In 1973, Sakharov was nominated for the Nobel Peace Prize and in 1974 was awarded the Prix mondial Cino Del Duca.

Sakharov was awarded the Nobel Peace Prize in 1975. The Norwegian Nobel Committee called him "a spokesman for the conscience of mankind". In the words of the Nobel Committee's citation: "In a convincing manner Sakharov has emphasised that Man's inviolable rights provide the only safe foundation for genuine and enduring international cooperation."

Sakharov was not allowed to leave the Soviet Union to collect the prize. His wife Yelena Bonner read his speech at the ceremony in Oslo, Norway. On the day the prize was awarded, Sakharov was in Vilnius, where human rights activist Sergei Kovalev was being tried. In his Nobel lecture, titled "Peace, Progress, Human Rights", Sakharov called for an end to the arms race, greater respect for the environment, international cooperation, and universal respect for human rights. He included a list of prisoners of conscience and political prisoners in the USSR, stating that he shares the prize with them.

By 1976 the head of the KGB Yuri Andropov was prepared to call Sakharov "Domestic Enemy Number One" before a group of KGB officers.

Internal exile (1980–1986)

The apartment building in Gagarina Avenue 214, Scherbinki district of Nizhny Novgorod where Sakharov lived in exile from 1980 to 1986. His apartment is now a museum.

Sakharov was arrested on 22 January 1980, following his public protests against the Soviet intervention in Afghanistan in 1979, and was sent to the city of Gorky, now Nizhny Novgorod, a city that was off limits to foreigners.

Between 1980 and 1986, Sakharov was kept under Soviet police surveillance. In his memoirs he mentions that their apartment in Gorky was repeatedly subjected to searches and heists. Sakharov was named the 1980 Humanist of the Year by the American Humanist Association.

In May 1984, Sakharov's wife, Yelena Bonner, was detained and Sakharov began a hunger strike, demanding permission for his wife to travel to the United States for heart surgery. He was forcibly hospitalized and force-fed. He was held in isolation for four months. In August 1984 Bonner was sentenced by a court to five years of exile in Gorky.

In April 1985, Sakharov started a new hunger strike for his wife to travel abroad for medical treatment. He again was taken to a hospital and force-fed. In August the Politburo discussed what to do about Sakharov. He remained in the hospital until October 1985 when his wife was allowed to travel to the United States. She had heart surgery in the United States and returned to Gorky in June 1986.

In December 1985, the European Parliament established the Sakharov Prize for Freedom of Thought, to be given annually for outstanding contributions to human rights.

On 19 December 1986, Mikhail Gorbachev, who had initiated the policies of perestroika and glasnost, called Sakharov to tell him that he and his wife could return to Moscow.

Political leader

In 1988, Sakharov was given the International Humanist Award by the International Humanist and Ethical Union. He helped to initiate the first independent legal political organizations and became prominent in the Soviet Union's growing political opposition. In March 1989, Sakharov was elected to the new parliament, the All-Union Congress of People's Deputies and co-led the democratic opposition, the Inter-Regional Deputies Group. In November the head of the KGB reported to Mikhail Gorbachev on Sakharov's encouragement and support for the coal-miners' strike in Vorkuta.

Death

Sakharov's grave, 1990

Soon after 21:00 on 14 December 1989, Sakharov went to his study to take a nap before preparing an important speech he was to deliver the next day in the Congress. His wife went to wake him at 23:00 as he had requested but she found Sakharov dead on the floor. According to the notes of Yakov Rapoport, a senior pathologist present at the autopsy, it is most likely that Sakharov died of an arrhythmia consequent to dilated cardiomyopathy at the age of 68. He was interred in the Vostryakovskoye Cemetery in Moscow.

Influence

Memorial prizes

The Sakharov Prize for Freedom of Thought was established in 1988 by the European Parliament in his honour, and is the highest tribute to human rights endeavours awarded by the European Union. It is awarded annually by the parliament to "those who carry the spirit of Soviet dissident Andrei Sakharov"; to "Laureates who, like Sakharov, dedicate their lives to peaceful struggle for human rights."

An Andrei Sakharov prize has also been awarded by the American Physical Society every second year since 2006 "to recognize outstanding leadership and/or achievements of scientists in upholding human rights".

The Andrei Sakharov Prize For Writer's Civic Courage was established in October 1990.

In 2004, with the approval of Yelena Bonner, an annual Sakharov Prize for journalism was established for reporters and commentators in Russia. Funded by former Soviet dissident Pyotr Vins, now a businessman in the US, the prize is administered by the Glasnost Defence Foundation in Moscow. The prize "for journalism as an act of conscience" has been won over the years by famous journalists such as Anna Politkovskaya and young reporters and editors working far from Russia's media capital, Moscow. The 2015 winner was Yelena Kostyuchenko.

Andrei Sakharov Archives and Human Rights Center

The Andrei Sakharov Archives and Human Rights Center, established at Brandeis University in 1993, are now housed at Harvard University. The documents from that archive were published by the Yale University Press in 2005. These documents are available online. Most of documents of the archive are letters from the head of the KGB to the Central Committee about activities of Soviet dissidents and recommendations about the interpretation in newspapers. The letters cover the period from 1968 to 1991 (Brezhnev stagnation). The documents characterize not only Sakharov's activity, but that of other dissidents, as well as that of highest-position apparatchiks and the KGB. No Russian equivalent of the KGB archive is available.

Cellular adaptation

From Wikipedia, the free encyclopedia
 
In cell biology and pathophysiology, cellular adaptation refers to changes made by a cell in response to adverse or varying environmental changes. The adaptation may be physiologic (normal) or pathologic (abnormal). Four types of morphological adaptations include atrophy, hypertrophy, hyperplasia, and metaplasia.

Atrophy

Atrophy is a decrease in cell size. If enough cells in an organ undergo atrophy the entire organ will decrease in size.Thymus atrophy during early human development (childhood) is an example of physiologic atrophy. Skeletal muscle atrophy is a common pathologic adaptation to skeletal muscle disuse (commonly called "disuse atrophy"). Tissue and organs especially susceptible to atrophy include skeletal muscle, cardiac muscle, secondary sex organs, and the brain.

Hypertrophy

Illustration of adipocytes of different sizes. In response to dietary excess energy intake, adipocytes adapt by increased storage of lipids, resulting in cellular hypertrophy.

Hypertrophy is an increase in cell size and volume. If enough cells of an organ hypertrophy the whole organ will increase in size. Hypertrophy may involve an increase in intracellular protein as well as cytosol (intracellular fluid) and other cytoplasmic components. For example, adipocytes (fat cells) may expand in size by depositing more lipid within cytoplasmic vesciles. Thus in human adults, increases in body fat tissue occurs mostly by increases in the size of adipocytes, not by increases in the number of adipocytes. Hypertrophy may be caused by mechanical signals (e.g., stretch) or trophic signals (e.g., growth factors). An example of physiologic hypertrophy is in skeletal muscle with sustained weight bearing exercise. An example of pathologic hypertrophy is in cardiac muscle as a result of hypertension.

Hyperplasia

Hyperplasia is an increase in the number of cells. It is the result of increased cell mitosis or division (also referred to as cell proliferation). The two types of physiologic hyperplasia are compensatory and hormonal. Compensatory hyperplasia permits tissue and organ regeneration. It is common in epithelial cells of the epidermis and intestine, liver hepatocytes, bone marrow cells, and fibroblasts. It occurs to a lesser extent in bone, cartilage, and smooth muscle cells. Hormonal hyperplasia occurs mainly in organs that depend on estrogen. For example, the estrogen-dependent uterine cells undergo hyperplasia and hypertrophy following pregnancy. Pathologic hyperplasia is an abnormal increase in cell division. A common pathologic hyperplasia in women occurs in the endometrium and is called endometriosis.

Metaplasia

Metaplasia occurs when a cell of a certain type is replaced by another cell type, which may be less differentiated. It is a reversible process thought to be caused by stem cell reprogramming. Stem cells are found in epithelia and embryonic mesenchyme of connective tissue. A prominent example of metaplasia involves the changes associated with the respiratory tract in response to inhalation of irritants, such as smog or smoke. The bronchial cells convert from mucus-secreting, ciliated, columnar epithelium to non-ciliated, squamous epithelium incapable of secreting mucus. These transformed cells may become dysplasic or cancerous if the stimulus (e.g., cigarette smoking) is not removed. The most common example of metaplasia is Barrett's esophagus, when the non-keratinizing squamous epithelium of the esophagus undergoes metaplasia to become mucinous columnar cells, ultimately protecting the esophagus from acid reflux originating in the stomach. If stress persists, metaplasia can progress to dysplasia and eventually carcinoma; Barrett's esophagus, for example, can eventually progress to adenocarcinoma.

Dysplasia

Dysplasia refers to abnormal changes in cellular shape, size, and/or organization. Dysplasia is not considered a true adaptation; rather, it is thought to be related to hyperplasia and is sometimes called "atypical hyperplasia". Tissues prone to dysplasia include cervical and respiratory epithelium, where it is strongly associated with the development of cancer; it may also be involved in the development of breast cancer. Although dysplasia is reversible, if stress persists, then dysplasia progresses to irreversible carcinoma.

Cell biology

From Wikipedia, the free encyclopedia

Cell biology is a branch of biology studying the structure and function of the cell, also known as the basic unit of life. Cell biology encompasses both prokaryotic and eukaryotic cells and can be divided into many sub-topics which may include the study of cell metabolism, cell communication, cell cycle, and cell composition. The study of cells is performed using several techniques such as cell culture, various types of microscopy, and cell fractionation. These have allowed for and are currently being used for discoveries and research pertaining to how cells function, ultimately giving insight into understanding larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences while also being essential for research in biomedical fields such as cancer, and other diseases. Research in cell biology is interconnected to other fields such as genetics, molecular genetics, biochemistry, molecular biology, medical microbiology, immunology, and cytochemistry.

History

Cells were first seen in 17th century Europe with the invention of the compound microscope. In 1665, Robert Hooke termed the building block of all living organisms as "cells" after looking at a piece of cork and observing a cell-like structure, however, the cells were dead and gave no indication to the actual overall components of a cell. A few years later, in 1674, Anton Van Leeuwenhoek was the first to analyze live cells in his examination of algae. All of this preceded the cell theory which states that all living things are made up of cells and that cells are the functional and structural unit of organisms. This was ultimately concluded by plant scientist, Matthias Schleiden and animal scientist, Theodor Schwann in 1839, who viewed live cells in plant and animal tissue, respectively. 19 years later, Rudolf Virchow further contributed to the cell theory, adding that all cells come from the division of pre-existing cells. Although widely accepted, there have been many studies that question the validity of the cell theory. Viruses, for example, lack common characteristics of a living cell, such as membranes, cell organelles, and the ability to reproduce by themselves. Scientists have struggled to decide whether viruses are alive or not and whether they are in agreement with the cell theory.

Techniques

Modern-day cell biology research looks at different ways to culture and manipulate cells outside of a living body to further research in human anatomy and physiology, and to derive medications. The techniques by which cells are studied have evolved. Due to advancements in microscopy, techniques and technology have allowed for scientists to hold a better understanding of the structure and function of cells. Many techniques commonly used to study cell biology are listed below:
  • Cell culture: Utilizes rapidly growing cells on media which allows for a large amount of a specific cell type and an efficient way to study cells.
  • Fluorescence microscopy: Fluorescent markers such as GFP, are used to label a specific component of the cell. Afterwards, a certain light wavelength is used to excite the fluorescent marker which can then be visualized.
  • Phase-contrast microscopy: Uses the optical aspect of light to represent the solid, liquid, and gas phase changes as brightness differences.
  • Confocal microscopy: Combines fluorescence microscopy with imaging by focusing light and snap shooting instances to form a 3-D image.
  • Transmission electron microscopy: Involves metal staining and the passing of electrons through the cells, which will be deflected upon interaction with metal. This ultimately forms an image of the components being studies.
  • Cytometry: The cells are placed in the machine which uses a beam to scatter the cells based on different aspects and can therefore separate them based on size and content. Cells may also be tagged with GFP-florescence and can be separated that way as well.
  • Cell fractionation: This process requires breaking up the cell using high temperature or sonification followed by centrifugation to separate the parts of the cell allowing for them to be studied separately.

Cell classification and composition

There are two fundamental classifications of cells: prokaryotic and eukaryotic. Prokaryotic cells are distinguished from eukaryotic cells by the absence of a cell nucleus or other membrane bound organelle. Prokaryotic cells are much smaller than eukaryotic cells, making them the smallest form of life. The study of eukaryotic cells is typically the main focus of cytologists, whereas prokaryotic cells are the focus of microbiologists.

Prokaryotic cells

A typical prokaryote cell.

Prokaryotic cells include Bacteria and Archaea, and lack an enclosed cell nucleus. They both reproduce through binary fission. Bacteria, the most prominent type, have several different shapes which include mainly spherical, and rod-shaped. Bacteria can be classed as either gram positive or gram negative depending on the cell wall composition. Bacterial structural features include:
  • Flagella: A tail-like structure that helps the cell to move.
  • Ribosomes: Used for translation of RNA to protein.
  • Nucleoid: Area designated to hold all the genetic material in a circular structure.
There are many process that occur in prokaryotic cells that allow them to survive. For instance, in a process termed conjugation, fertility factor allows the bacteria to possess a pilus which allows it to transmit DNA to another bacteria which lacks the F factor, permitting the transmittance of resistance allowing it to survive in certain environments.

Eukaryotic cells

A typical animal cell.

Eukaryotic cells can either be unicellular or multicellular and include animal, plant, fungi, and protozoa cells which all contain organelles with various shapes and sizes. These cells are composed of the following organelles:
  • Nucleus: This functions as the genome and genetic information storage for the cell, containing all the DNA organized in the form of chromosomes. It is surrounded by a nuclear envelope, which includes nuclear pores allowing for transportation of proteins between the inside and outside of the nucleus. The is also the site for replication of DNA as well as transcription of DNA to RNA. Afterwards, the RNA is modified and transported out to the cytosol to be translated to protein.
  • Nucleolus: This structure is within the nucleus, usually dense and spherical in shape. It is the site of ribosomal RNA (rRNA) synthesis, which is needed for ribosomal assembly.
  • Endoplasmic reticulum (ER): This functions to synthesize, store, and secrete proteins to the golgi apparatus.
  • Mitochondria: This functions for the production of energy or ATP within the cell. Specifically, this is the place where the Krebs cycle or TCA cycle for the production of NADH and FADH occurs. Afterwards, these products are used within the electron transport chain (ETC) and oxidative phosphorylation for the final production of ATP.
  • Golgi apparatus: This functions to further process, package, and secrete the proteins to their destination. The proteins contain a signal sequence which allows the golgi apparatus to recognize and direct it to the correct place.
  • Lysosome: The lysosome functions to degrade material brought in from the outside of the cell or old organelles. This contains many acid hydrolases, proteases, nucleases, and lipases, which breakdown the various molecules. Autophagy is the process of degradation through lysosomes which occurs when a vesicle buds off from the ER and engulfs the material, then, attaches and fuses with the lysosome to allow the material to be degraded.
  • Ribosomes: Functions to translate RNA to protein.
  • Cytoskeleton: This functions to anchor organelles within the cells and make up the structure and stability of the cell.
  • Cell membrane: The cell membrane can be described as a phospholipid bilayer and is also consisted of lipids and proteins. Because the inside of the bilayer is hydrophobic and in order for molecules to participate in reactions within the cell, they need to be able to cross this membrane layer to get into cell via osmotic pressure, diffusion, concentration gradients, and membrane channels.
  • Centrioles: Function to produce spindle fibers which are used to separate chromosomes during cell division.
Eukaryotic cells may also be composed of the following molecular components:
  • Chromatin: This makes up chromosomes and is a mixture of DNA with various proteins.
  • Cilia: They help to propel substances and can also be used for sensory purposes.

Processes

Cell metabolism

Cell metabolism is necessary for the production of energy for the cell and therefore its survival and includes many pathways. For cellular respiration, once glucose is available, glycolysis occurs within the cytosol of the cell to produce pyruvate. Pyruvate undergoes decarboxylation using the multi-enzyme complex to form acetyl coA which can readily be used in the TCA cycle to produce NADH and FADH2. These products are involved in the electron transport chain to ultimately form a proton gradient across the inner mitochondrial membrane. This gradient can then drive the production of ATP and H2O during oxidative phosphorylation. Metabolism in plant cells includes photosynthesis which is simply the exact opposite of respiration as it ultimately produces molecules of glucose.

Cell communication and signaling

Cell communication is important for cell regulation and for cells to process information from the environment and respond accordingly. Communication can occur through direct cell contact or endocrine, paracrine, and autocrine signaling. Direct cell-cell contact is when a receptor on a cell binds a molecule that is attached to the membrane of another cell. Endocrine signaling occurs through molecules secreted into the bloodstream. Paracrine signaling uses molecules diffusing between two cells to communicate. Autocrine is a cell sending a signal to itself by secreting a molecule that binds to a receptor on its surface. Forms of communication can be through:
  • Ion channels: Can be of different types such as voltage or ligand gated ion channels. The allow for the outflow and inflow of molecules and ions.
  • G-protein coupled receptor (GPCR): Is widely recognized to contain 7 transmembrane domains. The ligand binds on the extracellular domain and once the ligand binds, this signals a guanine exchange factor to convert GDP to GTP and activate the G-α subunit. G-α can target other proteins such as adenyl cyclase or phospholipase C, which ultimately produce secondary messengers such as cAMP, Ip3, DAG, and calcium. These secondary messengers function to amplify signals and can target ion channels or other enzymes. One example for amplification of a signal is cAMP binding to and activating PKA by removing the regulatory subunits and releasing the catalytic subunit. The catalytic subunit has a nuclear localization sequence which prompts it to go into the nucleus and phosphorylate other proteins to either repress or activate gene activity.
  • Receptor tyrosine kinases: Bind growth factors, further promoting the tyrosine on the intracellular portion of the protein to cross phosphorylate. The phosphorylated tyrosine becomes a landing pad for proteins containing an SH2 domain allowing for the activation of Ras and the involvement of the MAP kinase pathway.

Cell cycle

The process of cell division in the cell cycle.

The growth process of the cell does not refer to the size of the cell, but the density of the number of cells present in the organism at a given time. Cell growth pertains to the increase in the number of cells present in an organism as it grows and develops; as the organism gets larger so does the number of cells present. Cells are the foundation of all organisms and are the fundamental unit of life. The growth and development of cells are essential for the maintenance of the host and survival of the organism. For this process, the cell goes through the steps of the cell cycle and development which involves cell growth, DNA replication, cell division, regeneration, and cell death. The cell cycle is divided into four distinct phases: G1, S, G2, and M. The G phase – which is the cell growth phase – makes up approximately 95% of the cycle. The proliferation of cells is instigated by progenitors. All cells start out in an identical form and can essentially become any type of cells. Cell signaling such as induction can influence nearby cells to differentiate determinate the type of cell it will become. Moreover, this allows cells of the same type to aggregate and form tissues, then organs, and ultimately systems. The G1, G2, and S phase (DNA replication, damage and repair) are considered to be the interphase portion of the cycle, while the M phase (mitosis) is the cell division portion of the cycle. Mitosis is composed of many stages which include, prophase, metaphase, anaphase, telophase, and cytokinesis, respectively. The ultimate result of mitosis is the formation of two identical daughter cells. 

The cell cycle is regulated by a series of signaling factors and complexes such as cyclins, cyclin-dependent kinase, and p53. When the cell has completed its growth process and if it is found to be damaged or altered, it undergoes cell death, either by apoptosis or necrosis, to eliminate the threat it can cause to the organism's survival.

Pathology

The scientific branch that studies and diagnoses diseases on the cellular level is called cytopathology. Cytopathology is generally used on samples of free cells or tissue fragments, in contrast to the pathology branch of histopathology, which studies whole tissues. Cytopathology is commonly used to investigate diseases involving a wide range of body sites, often to aid in the diagnosis of cancer but also in the diagnosis of some infectious diseases and other inflammatory conditions. For example, a common application of cytopathology is the Pap smear, a screening test used to detect cervical cancer, and precancerous cervical lesions that may lead to cervical cancer.

Conscience clause in medicine in the United States

From Wikipedia, the free encyclopedia
 
Conscience clauses are legal clauses attached to laws in some parts of the United States and other countries which permit pharmacists, physicians, and/or other providers of health care not to provide certain medical services for reasons of religion or conscience. It can also involve parents withholding consenting for particular treatments for their children.

In many cases, the clauses also permit health care providers to refuse to refer patients to unopposed providers. Those who choose not to refer or provide services may not be disciplined or discriminated against. The provision is most frequently enacted in connection with issues relating to reproduction, such as abortion, sterilization, contraception, and stem cell based treatments, but may include any phase of patient care.

History

The earliest national conscience clause law in the United States, which was enacted immediately following the Supreme Court's decision in Roe v. Wade, applied only to abortion and sterilization. It was sponsored by Senator Frank Church of Idaho. The Church Amendment of 1973, passed by the Senate on a vote of 92-1, exempted private hospitals receiving federal funds under the Hill-Burton Act, Medicare and Medicaid from any requirement to provide abortions or sterilizations when they objected on “the basis of religious beliefs or moral convictions.” Nearly every state enacted similar legislation by the end of the decade—often with the support of legislators who otherwise supported abortion rights. Supreme Court Justice Harry Blackmun, the author of the Roe v. Wade majority opinion, endorsed such clauses “appropriate protection” for individual physicians and denominational hospitals.

According to Nancy Berlinger, of the bioethics research institute The Hastings Center, "...Conscientious objection in health care always has a social dimension and ...Laws and professional guidelines on conscientious objection in health care must balance the respect for an individual’s beliefs against the well-being of the general public."

Conscience clauses have been adopted by a number of U.S. states. including Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Pennsylvania, and South Dakota. There are some recent comprehensive reviews of federal and state conscience clause laws across the United States and in select other countries.

Some clauses address local concerns: Oregon, recognizes a physician's right to refuse to participate in physician-assisted suicide, although it is legal in that state.

Informed consent

An informed consent clause, although allowing medical professionals not to perform procedures against their conscience, does not allow professionals to give fraudulent information to deter a patient from obtaining such a procedure (such as lying about the risks involved in an abortion to deter one from obtaining one) in order to impose one's belief using deception. These principles were reaffirmed in the Utah Supreme Court's decision in Wood v. University of Utah Medical Center (2002). Commenting on the case, bioethicist Jacob Appel of New York University wrote that "if only a small number of physicians intentionally or negligently withhold information from their patients significant damage is done to the medical profession as a whole" because "pregnant women will no longer know whether to trust their doctors."

Right of Conscience Rule

The Right of Conscience Rule was a set of protections for healthcare workers enacted by President George W. Bush on December 18, 2008, allowing healthcare workers to refuse care based on their personal beliefs. Specifically, the rule denied federal funding to institutions that did not allow workers to refuse care that went against their beliefs. In February 2011, President Barack Obama rescinded the Right of Conscience Rule.

Pharmacists

States have historically provided a conscience clause right allowing pharmacists to refrain from participating in abortions. In April 2005, Governor Rod Blagojevich by emergency executive order required all pharmacists to provide Plan B levonorgestrel. In September 2012, the Illinois Appellate Court found the Governor's order violated Illinois law.

In June 2006, the Pharmacy Board of the Washington State Department of Health rejected a draft rule proposed by Governor Christine Gregoire to require all pharmacies to begin carrying Plan B. Governor Gregoire responded by releasing a public statement warning the Board members to reconsider or they could be removed. In July 2006, the Washington State Human Rights Commission warned the Board members that they would be personally liable for illegally discriminating against women if they did not pass the Governor's Plan B rule.  In April 2007, the Board approved a final rule prohibiting pharmacies from not stocking Plan B for religious reasons but allowing exemptions for “good faith” business reasons.

When Ralph's Thriftway, a grocery store in Olympia, Washington, refused for religious reasons to carry Plan B, it was widely boycotted, leading Gregoire to cancel the grocer's longstanding account with the Washington Governor's Mansion. The only complaints for violating the Plan B rule were filed against the grocer. Half of Washington's hospitals are Catholic. The grocer sued but, instead of alleging violations of the broader Constitution of Washington, its attorneys at the Alliance Defending Freedom and the Becket Fund for Religious Liberty only filed under the Free Exercise Clause of the United States Constitution. The case is known as Stormans, Inc. v. Wiesman

On November 8, 2007, U.S. District Judge Ronald B. Leighton granted the grocer a preliminary injunction blocking the rule. On May 1, 2008, United States Court of Appeals for the Ninth Circuit Judges Thomas G. Nelson and Jay Bybee denied the state a stay of the injunction pending appeal, over a dissent by Judge A. Wallace Tashima. However, on July 8, 2009, Circuit Judge Kim McLane Wardlaw, joined by Richard Clifton and N. Randy Smith reversed the preliminary injunction.

On February 22, 2012, after four years of discovery and a twelve-day bench trial, Judge Leighton issued a permanent injunction blocking the Plan B rule as unconstitutional. On July 23, 2015, Circuit Judge Susan P. Graber, joined by Judges Mary H. Murguia and Richard Clifton reversed. The grocer's petition for certiorari from the Supreme Court of the United States was denied on June 28, 2016. Justice Samuel Alito, joined by Chief Justice John Roberts and Justice Clarence Thomas, dissented, writing that “the rules challenged here reflect antipathy towards religious beliefs that do not accord with the views of those holding the levers of government power.”

In 2014 and 2016, Senator Cory Booker introduced the “Access to Birth Control Act” bill, which would require all pharmacists in the United States to provide emergency contraception.

Responses

Health care providers opposed to abortion or contraception support the clauses because they believe that disciplinary or legal action for refusing to perform services obliges providers to supply services which their moral or religious principles forbid.

Reproductive rights organizations, such as Planned Parenthood and NARAL Pro-Choice America, oppose the provision because they maintain that pharmacists, doctors, and hospitals have a professional duty to fulfill patients' legal medical needs, regardless of their own ethical stances. Opponents see conscience clauses as an attempt to limit reproductive rights in lieu of bans struck down by Supreme Court rulings such as Roe v. Wade.

As a result, the term "conscience clause" is controversial and primarily used by those who support these provisions. Those who oppose them often prefer to use the term "refusal clause," implying that those who exercise the clauses are refusing to treat a patient.

Catholic doctrine

The conscience clause is widely invoked in Catholic universities, hospitals, and agencies because the Catholic Church opposes abortion, contraceptives, sterilization, and embryonic stem cell treatments. Opponents of related FOCA legislation have interpreted the possible end of the conscience clause as a demand to either "do abortions or close." Timothy Dolan has said, "“In effect, the president is saying we have a year to figure out how to violate our consciences." However, conscience clauses are sometimes interpreted differently and their use will often depend on the given context.

Public health specialists have questioned whether "conscience clauses" are ethical, observing in an article on the danger to miscarrying patients created by hospital anti-abortion policies that "in some Catholic-owned hospitals, the private patient–physician relationship, patient safety, and patient comfort are compromised by religious mandates that require physicians to act contrary to the current standard of care in miscarriage management."

Cooperative

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