The Proteasome The Cells Waste Disposer
What is a proteasome? A human cell contains about 30,000 proteasomes: these barrel-formed structures can break down practically all proteins to 7-9-amino-acid-long peptides. The active surface of the proteasome is within the barrel where it is shielded from the rest of the cell. The only way in to the active surface is via the lock, which recognises polyubiquitinated proteins, denatures them with ATP energy and admits them to the barrel for disassembly once the ubiquitin label has been removed. The peptides formed are released from the other end of the proteasome. Thus the proteasome itself cannot choose proteins; it is chiefly the E3 enzyme that does this by ubiquitin-labelling the right protein for breakdown .
Fig 3. The cells waste disposer, the proteasome. The black spots indicate active, protein-degrading surfaces.
More recent research
While the biochemical mechanisms underlying ubiquitin-labelled protein degradation were laid bare around 1983 its physiological significance had not yet been fully understood. That it is of importance in destroying defective intracellular proteins was known but, to proceed, a mutated cell was needed in the ubiquitin system. By studying in detail how the mutated cell differs from a normal cell under various growth conditions, it was hoped to gain a better idea of what reactions in the cell depend on the ubiquitin system.
How Safe Is Proton Therapy
After 3 years, 46% of patients in the proton therapy group and 49% of those in the traditional radiation therapy group were cancer free. Fifty-six percent of people who received proton therapy and 58% of those who received traditional radiation were still alive after 3 years.
Hans Geiger And Ernest Marsden
The;GeigerMarsden experiment; were a landmark series of experiments by which scientists discovered that every;atom;contains a nucleus where its positive charge and most of its mass are concentrated. They deduced this by measuring how an;alpha particle;beam is scattered when it strikes a thin metal foil. The experiments were performed between 1908 and 1913 by;Hans Geiger;and;Ernest Marsden;under the direction of;Ernest Rutherford;at the Physical Laboratories of the;University of Manchester.
Wikipedia contributors. “GeigerMarsden experiment.”;Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 8 Nov. 2016. Web. 8 Nov. 2016.
Hans Geiger best known as the co-inventor of the Geiger counter and for the Geiger-Marsden experiment which discovered the atomic nucleus.
In 1902 Geiger started studying physics and mathematics in University of Erlangen. In 1909, he and Ernest Marsden conducted the famous Geiger-Marsden experiment called the gold foil experiment. Together they created the Geiger counter. In 1911, Geiger and John Mitchell Nuttall discovered the Geiger-Nuttall law , which led to Rutherford’s atomic model. In 1928 Geiger and his student Walther Müller created an improved version of the Geiger counter, the Geiger-Müller counter.
Reference: “Ernest Marsden” Chemistry Encyclopedia. 23 September 2011.Reference: “Ernest Marsden” National Library of New Zealand. 23 September 2011
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How Big Was The Blast
The blast destroyed the immediate dockside area, creating a crater approximately 140m wide, which flooded with seawater.
The warehouse where the initial fire and explosions were observed was obliterated and an adjacent grain silo was heavily damaged.
Satellite images show complete devastation in the port area, with one ship apparently blown out of the water and onto the dockside.
The explosion’s shockwave blew out windows at Beirut International Airport’s passenger terminal, about 9km away from the port.
The blast was also heard as far away as Cyprus, about 200km across the Mediterranean Sea, and seismologists at the United States Geological Survey said it was the equivalent of a 3.3-magnitude earthquake.
Based on an analysis of videos, a team from the University of Sheffield estimated that the explosion was the equivalent of 1,000 to 1,500 tonnes of TNT – about a 10th of the intensity of the nuclear bomb dropped on Hiroshima in 1945.
“Whatever the precise charge size, this is unquestionably one of the largest non-nuclear explosions in history, far bigger than any conventional weapon,” said Professor Andy Tyas, an expert on blast protection engineering.
The Case For William Austin
Roscoe and Harden have noted that Dalton’s laboratory notebook shows that he was referring to Austin’s 1788 paper on the composition of ammonia just a page before his first table of atomic weights appeared on 6 September 1803., His use of Austin’s data has been interpreted as a method to double-check his atomic weights, as opposed to demonstrating any theoretical insight into chemical combination that Dalton might have obtained from Austin.
But the question arises of why Dalton was using a paper written in 1788, when in his New System he described Davy’s analytical results on ammonia, published in 1800, as follows: This conclusion was so nearly agreeing with the previous determination of Berthollet, that both have justly been held up as specimens of the accuracy of modern chemical analysis. Thomson reached the same conclusion in 1802, noting in his System of Chemistry that the ammonia results obtained by Berthollet have been still farther confirmed by those made more lately by Mr Davy. In spite of this, Dalton waited for two years, not making the switch to Berthollet’s data until 1805.
If we consider the great difficulty of obtaining these specific gravities with exactness, we must be pleased to find so near a concurrence , and place more confidence in experiments on the specific gravities and combinations of aëriform bodies, than has generally been given them.
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Other chemists perceived links between atomic weights and chemical properties, but it was not until the 1860s that atomic weights had been well enough understood and measured for deeper insights to emerge. In England, the chemist John Newlands noticed that arranging the known elements in order of increasing atomic weight produced a recurrence of chemical properties every eighth element, a pattern he called the law of octaves in an 1865 paper. But Newlands pattern did not hold up very well after the first couple of octaves, leading a critic to suggest that he should try arranging the elements in alphabetical order instead. Clearly, the relationship of element properties and atomic weights was a bit more complicated, as Mendeleev soon realized.
Organizing the elements
Born in Tobolsk, in Siberia, in 1834 , Mendeleev lived a dispersed life, pursuing multiple interests and traveling a higgledy-piggledy path to prominence. During his higher education at a teaching institute in St. Petersburg, he nearly died from a serious illness. After graduation, he taught at middle schools , and while teaching math and science, he conducted research for his masters degree.
He then worked as a tutor and lecturer until earning a fellowship for an extended tour of research at Europes most prominent university chemistry laboratories.
Chemistry Council Names Schneider Logistics Named Responsible Care Partner Of The Year
GREEN BAY, Wis.Schneider Logistics has been named a Responsible Care Partner of the Year, becoming the first logistics management company to receive this prestigious honour, said a company release.
Responsible Care® is a voluntary initiative in which companies work together to continuously improve their health, safety and environmental performance and to communicate about their products and processes.
The Responsible Care Partner of the Year Award is the American Chemistry Councils top award and has been presented annually since 2010. It recognizes high performance and safety records of companies involved in the distribution, transportation, storage, use, treatment, disposal and/or sales and marketing of chemicals. The winners must have completed all Responsible Care certification obligations and had zero fatalities in the past calendar year.
Becoming a member of Responsible Care in 2009 was a natural step for us, as it aligns with Schneiders core value of safety first and always, said Dan Van Alstine, Schneiders senior vice president and general manager, Dedicated Services and Logistics. We are passionate about managing the transportation functions for our customers in an efficient and effective manner, but we are equally passionate about doing that work in the safest way possible. Like the ACC, we are never satisfied with being good enough, and we continually search for ways to help our customers improve our shared safety performance.
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Development And Dismantling Of Phlogiston
In 1702, German chemist Georg Stahl coined the name “phlogiston” for the substance believed to be released in the process of burning. Around 1735, Swedish chemist Georg Brandt analyzed a dark blue pigment found in copper ore. Brandt demonstrated that the pigment contained a new element, later named cobalt. In 1751, a Swedish chemist and pupil of Stahl’s named Axel Fredrik Cronstedt, identified an impurity in copper ore as a separate metallic element, which he named nickel. Cronstedt is one of the founders of modern mineralogy. Cronstedt also discovered the mineral scheelite in 1751, which he named tungsten, meaning “heavy stone” in Swedish.
In 1754, Scottish chemist Joseph Black isolated carbon dioxide, which he called “fixed air”. In 1757, Louis Claude Cadet de Gassicourt, while investigating arsenic compounds, creates Cadet’s fuming liquid, later discovered to be cacodyl oxide, considered to be the first synthetic organometallic compound. In 1758, Joseph Black formulated the concept of latent heat to explain the thermochemistry of phase changes. In 1766, English chemist Henry Cavendish isolated hydrogen, which he called “inflammable air”. Cavendish discovered hydrogen as a colorless, odourless gas that burns and can form an explosive mixture with air, and published a paper on the production of water by burning inflammable air in dephlogisticated air , the latter a constituent of atmospheric air .
Seeking Advice: A Proposition To Lecture At The Royal Institution
In January 1802, Allen was asked by William Babington, a physician and fellow member of Higgins’s society, for assistance in presenting chemical lectures at Guy’s Hospital, which he had given for more than a dozen years on his own. The BabingtonAllen lectures were evidently a success, the 1802 syllabus was issued, and Allen received a letter from Humphry Davy on 4 July 1803 asking him whether he would repeat the Guy’s Hospital lectures at the Royal Institution as a solo lecturer. Allen evidently trusted Babington’s opinion, for on 7 July he consulted his co-lecturer, who advised him to accept Davy’s offer.
Three days later, Allen met with John Dalton, who was also under consideration for a lecture course, and the two discussed Davy’s offer. His diary entry for 10 July 1803 reads, John Dalton of Manchester here at teaconversed with him about the proposition from the Royal Institution to lecture there, he being one of those applied to. From a diary entry in 1802 Allen was anxious about his performance as a lecturer, which is why he sought out the advice of Babington and Dalton. However, he actually had little to be concerned about: as noted in his diary, he was able to provide an on-the-spot summary of the particles of matter at one lecture on the elements, which was very well received by his audience.
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The Dielectric And Magnetic Susceptibilities
The interpretation of the potentials in terms of polarization and magnetization is of fundamental importance in the atomic theory of matter. From the standpoint of such a theory the additive relations § 2.2 and connecting E with D and P and H with B and M have a more direct physical meaning than the multiplicative relations and , in § 1.1).
In the atomic theory one regards matter as composed of interacting particles embedded in the vacuum. These entities produce a field which has large local variations in the interior of the matter. This internal field is modified by any field which is applied externally; the properties of the matter are then derived by averaging over the total field within it. As long as the region over which the average is taken is large compared with the linear dimensions of the particles, the electromagnetic properties of each can be simply described by an electric and a magnetic dipole; the secondary field is then the field due to these dipoles . This is, in fact, exactly what we have just described by regarding matter as a continuous distribution interacting with the field: it corresponds to the first approximation of the atomic theory. In this approximation for sufficiently weak fields one can assume P and M to be proportional to E and H respectively:
David Favrholdt, in, 1999
Measuring Global Sea Level
Global sea level is the height of the ocean’s surface averaged throughout the world, and is what is often discussed in the news. Historically, it has been challenging to measure because the ocean’s surface isn’t flat; it changes daily or hourly based on winds, tides, and currents. Up until 1993, tide gauges measured global sea level. Tide gauges are usually placed on piers, and they continuously record the height of the water level compared to a stable reference point on land. There are around 2,000 tide gauges around the world run by around 200 countries. Some have been recording sea level data since the 1800sand a few for even longer.
In 2002, NASA launched the GRACE satellites, which track both ocean and ice mass by measuring changes in the Earth’s gravitational field. The paired satellites orbit the Earth together and are spaced roughly 200 kilometers apart. Ice and water moving around the Earth exert different gravitational forces on the GRACE satellites. The satellites can sense the miniscule changes in the distance between one another caused by the change in gravitation force, which they measure and use to track water and ice mass change. It’s thanks to GRACE that we know where the water flowing into the ocean came from. According to GRACE, melting of ice in Greenland increased sea level by 0.74 mm/year and melting in Antarctica by 0.25 mm/year since 2002.
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Mechanisms Underlying Sids Deaths
Based on the fact that the definition of SIDS is dependent on the elimination of known causes of death, it is not surprising that there are no identifiable mechanisms underlying these deaths. This has led to a vast number of theories on the mechanisms responsible for SIDS. Chapters throughout this book will provide in-depth discussions on the proposed causation of SIDS, but below is a short summary of some of the current theories, all of which, obviously, have yet to be fully substantiated. It is also worth noting that in many studies there is a lack of comparative normal controls, which complicates our ability to interpret whether entities present in SIDS infants represent a primary cause of death or act as a secondary, or even an unrelated, phenomenon. Indeed, the authors of this chapter, along with others, are of the opinion that infant deaths attributed to SIDS are likely to represent a mixed population with various etiologies and disease entities contributing to one common endpoint rather than all deaths being attributed to one single cause .
There’s No Place Like Home
Not only humans, but other animals that rely on low-lying habitats will be impacted by sea level rise. Many birds use coasts and coastal ecosystems for breeding, laying eggs, finding food, or simply as a place to live. Sea turtles lay their eggs on beaches, returning to the same location every year. When beaches erode, or are covered by rising seas their options become more and more limited. Physical barriers that humans are considering to stop the rising seas, like sea walls, completely impede the turtles from coming ashore to build nests and lay eggs.;
Species that are only found on islands are especially vulnerable, as their range is limited and they tend to already be vulnerable to extinction. With sea level rise animals like seabirds may not be able to react quickly enough to changes and their only homes may be inundated. ;
Saltwater intrusion will mean that coastal plant and tree species that cant handle salt water may die off, and a change in species biodiversity may occur. Along New York’s Long Island Sound, for example, tidal marsh plants have moved into previously forested areas flooded by rising sea level. This is natural ecological adaptation, wherein organisms that are better suited to regular saltwater flooding can now thrive in the area. Over time, a diverse and healthy marsh ecosystem may develop in its place.
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What You Will Learn
- An overview of the pharmacology of ionization
- Describe the process of postmortem drug redistribution
- Recognize limitations when interpreting postmortem results
The Fine Print
ACS Webinars®;does not endorse any products or services. The views expressed in this presentation are those of the presenters and do not necessarily reflect the views or policies of the American Chemical Society.
John Dalton And The Scientific Method
Dalton proposed his atomic theory in 1808; another century passed before the theory was universally accepted by scientists.
Ford Madox Brown, British, 18211893, Dalton Collecting Marsh Gas Fire , ca. 1880, mural.
Many consider 2008 the 200th anniversary of atomic theory, John Daltons momentous theory of the nature of matter. Dalton proposed that all matter in the universe is made of indestructible, unchangeable atomseach type characterized by a constant massthat undergo chemical reactions by joining with and separating from each other. But anniversaries can be deceptive. It was 1808 when Dalton published the first volume of New Systems of Chemical Philosophy, which presented his atomic theory in full, but his ideas were in fact already known, as he had been talking and writing about them for at least five years. Yet, an additional century would pass before atomic theory became universally accepted.;
The theory certainly had its early fans, including Swedish chemist Jöns Jakob Berzelius . There was hard evidence in its favor; conceiving of atoms in this way explained the stoichiometry of reactions, which posited that combined elements retained their proportions before, during, and after reacting with each other. However, not everyone found this fact compelling. Humphry Davy and Claude-Louis Berthollet were not convinced. Because atoms could not be seen, Dalton could not base his theory on direct observation, and this was a major stumbling block for many scientists.;
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