serendipitous

Comet Shoemaker-Levy 9 (SL9, formally designated D/1993 F2) was a comet which collided with Jupiter in 1994, providing the first direct observation of the collision of two solar system objects. This generated a large amount of coverage in the popular media, and SL9 was closely observed by astronomers worldwide. The comet provided many revelations about Jupiter and its atmosphere and highlighted Jupit ...

Including:

• Comet Shoemaker-Levy 9 - Discovery
• Comet Shoemaker-Levy 9 - A Jupiter-orbiting comet
• Comet Shoemaker-Levy 9 - Predictions for the collision
• Comet Shoemaker-Levy 9 - Impacts
• Comet Shoemaker-Levy 9 - Observations and discoveries
• Comet Shoemaker-Levy 9 - Chemical studies
• Comet Shoemaker-Levy 9 - Seismic waves
• Comet Shoemaker-Levy 9 - Other observations
• Comet Shoemaker-Levy 9 - Post-impact analysis
• Comet Shoemaker-Levy 9 - Longer term effects
• Comet Shoemaker-Levy 9 - Frequency of impacts
• Comet Shoemaker-Levy 9 - Jupiter as a cosmic vacuum cleaner

Read more here: » Comet Shoemaker-Levy 9: Encyclopedia - Comet Shoemaker-Levy 9

Click image for description Uranus (pronounced either /ˈjuɹənəs/ or /jəˈɹeɪnəs/) is the seventh planet from the Sun. It is a gas giant, the third largest by diameter and fourth largest by mass. It is named after Uranus, the Greek god of the sky, and progenitor of the other gods. Its symbol is either ♅ (Unicode U+2645, mo ...

Including:

• Uranus - Physical characteristics
• Uranus - Composition
• Uranus - Axial tilt
• Uranus - Magnetic Field
• Uranus - Discovery and naming
• Uranus - Planetary rings
• Uranus - Natural satellites
• Uranus - Visibility
• Uranus - Uranus in fiction

Read more here: » Uranus: Encyclopedia - Uranus

The existence of pentaquarks was originally hypothesized by Maxim Polyakov, Dmitri Diakonov, and Victor Petrov at the Petersburg Nuclear Physics Institute in Russia in 1997, but their predictions were met with skepticism. Nevertheless, the existence of pentaquarks was first reported in July 2003 from experiments run by Takashi Nakano of Osaka University, Japan, and by Ken Hicks at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia. Their experiments caused a high-energy gamma ray to interact with a n ...

See also:

Pentaquark, Pentaquark - History

Read more here: » Pentaquark: Encyclopedia II - Pentaquark - History

Drug discovery is the process by which drugs are discovered and/or designed. In the past most drugs have been discovered either by identifying the active ingredient from traditional remedies or by serendipitous discovery. The new approach has been to understand how disease and infection are controlled at the molecular and physiology level and to target specific entities based on this knowledge. New drugs begin in the laboratory with chemists, scientists and pharmacologists who identify cellular and genetic factors that play a role in ...

See also:

Pharmaceutical company, Pharmaceutical company - History, Pharmaceutical company - Biotechnology company, Pharmaceutical company - Drug discovery, Pharmaceutical company - Target identification, Pharmaceutical company - Target prioritization/validation, Pharmaceutical company - Lead identification, Pharmaceutical company - Lead optimization, Pharmaceutical company - Drug development, Pharmaceutical company - Phase I Clinical Studies, Pharmaceutical company - Phase II Clinical Studies, Pharmaceutical company - Phase III Clinical Studies, Pharmaceutical company - New Drug Application, Pharmaceutical company - Orphan drug, Pharmaceutical company - Post-approval surveillance, Pharmaceutical company - Phase IIIb/IV Studies, Pharmaceutical company - Post-Market Studies, Pharmaceutical company - Products, Pharmaceutical company - Drug information, Pharmaceutical company - ICD and DRG, Pharmaceutical company - Revenues, Pharmaceutical company - Industry revenues, Pharmaceutical company - Patents and Generics, Pharmaceutical company - Medicare Part D, Pharmaceutical company - Sales and marketing, Pharmaceutical company - The pharmaceutical industry is different, Pharmaceutical company - Advertising to physicians, Pharmaceutical company - Direct to consumer, Pharmaceutical company - The payers, Pharmaceutical company - Mergers acquisitions and co-marketing of drugs, Pharmaceutical company - Controversy, Pharmaceutical company - Bibliography, Pharmaceutical company - Controversy, Pharmaceutical company - Drug discovery and development, Pharmaceutical company - Management mergers acquisitions co-marketing deals, Pharmaceutical company - Sales and marketing

Read more here: » Pharmaceutical company: Encyclopedia II - Pharmaceutical company - Drug discovery

Penicillin was originally isolated from the Penicillium chrysogenum (formerly Penicillium notatum) mold. The antibiotic effect was originally discovered by a young French medical student Ernest Duchesne studying Penicillium glaucum in 1896, but his discovery was ignored by the Institut Pasteur. Another Institut Pasteur scientist, Costa Rican Dr. Clodomiro Picado Twight was the first to record the ant ...

See also:

Penicillin, Penicillin - History, Penicillin - Mode of action, Penicillin - Variants in clinical use, Penicillin - Benzathine penicillin, Penicillin - Benzylpenicillin penicillin G, Penicillin - Phenoxymethylpenicillin penicillin V, Penicillin - Procaine penicillin, Penicillin - Adverse effects, Penicillin - Adverse drug reactions, Penicillin - Allergy/hypersensitivity, Penicillin - Resistance, Penicillin - Developments from penicillin, Penicillin - Biosynthesis

Read more here: » Penicillin: Encyclopedia II - Penicillin - History

History of cancer chemotherapy - Zubrod's initiatives. In 1956, C. Gordon Zubrod, who had formerly led the development of antimalarial agents for the United States Army took over the Division of Cancer Treatment of the NCI, and guided development of new drugs. In the two decades that followed, the establishment of the NCCSC, a large network of cooperative clinical trial groups evolved under the auspices of the NCI to test anticancer agents. Zubrod had a particular interest in natural products, and established a b ...

See also:

History of cancer chemotherapy, History of cancer chemotherapy - The first efforts 1940–1950, History of cancer chemotherapy - Another leap forward - The antifolates, History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US, History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet, History of cancer chemotherapy - Adjuvant therapy, History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere, History of cancer chemotherapy - Zubrod's initiatives, History of cancer chemotherapy - The taxanes, History of cancer chemotherapy - The camptothecins, History of cancer chemotherapy - Platinum-based agents, History of cancer chemotherapy - Nitrosoureas, History of cancer chemotherapy - Anthracyclcines and epipodophyllotoxins, History of cancer chemotherapy - Supportive care during chemotherapy, History of cancer chemotherapy - A period of quiet, History of cancer chemotherapy - Targeted therapy, History of cancer chemotherapy - Tyrosine kinase inhibitors, History of cancer chemotherapy - Monoclonal antibodies, History of cancer chemotherapy - Concluding Comments

Read more here: » History of cancer chemotherapy: Encyclopedia II - History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere

The process of finding a new drug against a chosen target for a particular disease usually involves high-throughput screening (HTS), wherein large libraries of chemicals are tested for their ability to modify the target. For example, if the target is a novel GPCR, compounds will be screened for their ability to inhibit or stimulate that receptor (see antagonist and agonist): if the target is a protein kinase, the chemicals w ...

See also:

Drug discovery, Drug discovery - Targets: New and Established, Drug discovery - Screening and Design, Drug discovery - Notes and references

Read more here: » Drug discovery: Encyclopedia II - Drug discovery - Screening and Design

Anticipation was high as the predicted date for the collisions approached, and astronomers trained their telescopes on Jupiter. Several space observatories did the same, including the Hubble Space Telescope, the ROSAT X-ray observing satellite, and significantly the Galileo spacecraft, then on its way to a rendezvous with Jupiter scheduled for 1996. While the impacts would take place on the side of Jupiter hidden from Earth, Galileo, then at a distance of 1.6 AU from the planet, would be able to see the impacts as they occurred. Jupiter's rapid rotation would bring the impact sites into view for terrest ...

See also:

Comet Shoemaker-Levy 9, Comet Shoemaker-Levy 9 - Discovery, Comet Shoemaker-Levy 9 - A Jupiter-orbiting comet, Comet Shoemaker-Levy 9 - Predictions for the collision, Comet Shoemaker-Levy 9 - Impacts, Comet Shoemaker-Levy 9 - Observations and discoveries, Comet Shoemaker-Levy 9 - Chemical studies, Comet Shoemaker-Levy 9 - Seismic waves, Comet Shoemaker-Levy 9 - Other observations, Comet Shoemaker-Levy 9 - Post-impact analysis, Comet Shoemaker-Levy 9 - Longer term effects, Comet Shoemaker-Levy 9 - Frequency of impacts, Comet Shoemaker-Levy 9 - Jupiter as a cosmic vacuum cleaner

Read more here: » Comet Shoemaker-Levy 9: Encyclopedia II - Comet Shoemaker-Levy 9 - Impacts

If there is a dynamic coefficient of friction between two objects of 0.20, and vibration causes them to be in contact only half of the time, that would be equivalent to a constant coefficient of friction of 0.10. This substantial reduction in friction can have a profound effect on the system. World War II Panzer tank treads lubricated by their own squeak provide the most famous, if serendipitous, example. Another example occurs during landslides. Most landslides do not involve this effect, but occasionally the frequency of vibrations ...

See also:

Acoustic lubrication, Acoustic lubrication - Examples, Acoustic lubrication - Applications

Read more here: » Acoustic lubrication: Encyclopedia II - Acoustic lubrication - Examples

The rationale behind the use of a prodrug is generally for ADME optimization. Prodrugs are usually designed to improve oral bioavailability - poor absorption from the gastrointestinal tract is usually the limiting factor, and is often due to the chemical properties of the drug. In rational drug design, the knowledge of chemical properties likely to improve absorption and the major metabolic pathways in the body allows the modification of the structure of new chemical entities for improved bioavailability. However, sometimes the use of ...

See also:

Prodrug, Prodrug - Rationale, Prodrug - Selected examples

Read more here: » Prodrug: Encyclopedia II - Prodrug - Rationale

Uranus - Composition. Uranus is composed primarily of rocks and various ices, with only about 15% hydrogen and a little helium (in contrast to Jupiter and Saturn which are mostly hydrogen). Uranus (like Neptune) is in many ways similar to the cores of Jupiter and Saturn minus the massive liquid metallic hydrogen envelope. It appears that Uranus does not have a rocky core like Jupiter and Saturn but rather that its material is more or less uniformly distributed. Uranus' cyan color is due to the absorption of red light by atmospheric methane. Surface temperature on Uranus's cloud cover is approx ...

See also:

Uranus, Uranus - Physical characteristics, Uranus - Composition, Uranus - Axial tilt, Uranus - Magnetic Field, Uranus - Discovery and naming, Uranus - Planetary rings, Uranus - Natural satellites, Uranus - Visibility, Uranus - Uranus in fiction

Read more here: » Uranus: Encyclopedia II - Uranus - Physical characteristics

There are many things to consider that affect the hitchhiker's chances of catching a ride. Some of these include: Traffic density: Catching a ride does of course depend on there being people to offer one. If someone is trying to hitchhike and only sees a vehicle go by every half-hour, it may be to their advantage to walk to a more frequently travelled road. There does however appear to be a maximum as well. Once the frequency of the traffic becomes too high, the chance of someone stopping actually appears to drop. This may occu ...

See also:

Hitchhiking, Hitchhiking - Method, Hitchhiking - Reasons, Hitchhiking - Reputation, Hitchhiking - Chances of getting a ride, Hitchhiking - Hitchhiking in literature, Hitchhiking - Safety, Hitchhiking - Crime, Hitchhiking - Road Safety, Hitchhiking - Miscellaneous

Read more here: » Hitchhiking: Encyclopedia II - Hitchhiking - Chances of getting a ride

Joseph Burchenal, at Memorial Sloan-Kettering Cancer Center in New York, with Farber's help, started his own methotrexate study and found the same effects. He then decided to try and develop anti-metabolites in the same way as Farber - making small changes in a metabolite needed by a cell to divide. With George Hitchings and Gertrude Elion, two pharmaceutical chemists who were working at the Burroughs Wellcome Company in Tuckahoe many purine analogues were tested which culmin ...

See also:

History of cancer chemotherapy, History of cancer chemotherapy - The first efforts 1940–1950, History of cancer chemotherapy - Another leap forward - The antifolates, History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US, History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet, History of cancer chemotherapy - Adjuvant therapy, History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere, History of cancer chemotherapy - Zubrod's initiatives, History of cancer chemotherapy - The taxanes, History of cancer chemotherapy - The camptothecins, History of cancer chemotherapy - Platinum-based agents, History of cancer chemotherapy - Nitrosoureas, History of cancer chemotherapy - Anthracyclcines and epipodophyllotoxins, History of cancer chemotherapy - Supportive care during chemotherapy, History of cancer chemotherapy - A period of quiet, History of cancer chemotherapy - Targeted therapy, History of cancer chemotherapy - Tyrosine kinase inhibitors, History of cancer chemotherapy - Monoclonal antibodies, History of cancer chemotherapy - Concluding Comments

Read more here: » History of cancer chemotherapy: Encyclopedia II - History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US

Shortly after World War II, a second approach to drug therapy of cancer began. Sidney Farber, a pathologist at Harvard Medical School studied the effects of folic acid on leukemia patients. Folic acid, a vitamin crucial for DNA metabolism had been discovered by Lucy Wills in 1937. It seemed to stimulate the proliferation of acute lymphoblastic leukaemia (ALL) cells when administered to children with this cancer. In one of the first examples of rational drug design (rather than accidental discovery), in collaboration with Harriett Kilte and L ...

See also:

History of cancer chemotherapy, History of cancer chemotherapy - The first efforts 1940–1950, History of cancer chemotherapy - Another leap forward - The antifolates, History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US, History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet, History of cancer chemotherapy - Adjuvant therapy, History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere, History of cancer chemotherapy - Zubrod's initiatives, History of cancer chemotherapy - The taxanes, History of cancer chemotherapy - The camptothecins, History of cancer chemotherapy - Platinum-based agents, History of cancer chemotherapy - Nitrosoureas, History of cancer chemotherapy - Anthracyclcines and epipodophyllotoxins, History of cancer chemotherapy - Supportive care during chemotherapy, History of cancer chemotherapy - A period of quiet, History of cancer chemotherapy - Targeted therapy, History of cancer chemotherapy - Tyrosine kinase inhibitors, History of cancer chemotherapy - Monoclonal antibodies, History of cancer chemotherapy - Concluding Comments

Read more here: » History of cancer chemotherapy: Encyclopedia II - History of cancer chemotherapy - Another leap forward - The antifolates

The definition of "target" itself is something debated within the pharmaceutical industry. However, the distinction between a "new" and "established" target can be made without a full understanding of just what a "target" is. This distinction is typically made by pharmaceutical companies engaged in discovery and development of small molecule therapeutics. "Established targets" are those for which there is a good scientific understanding, supported by a lengthy publication history, of both how the target functions in normal physiology ...

See also:

Drug discovery, Drug discovery - Targets: New and Established, Drug discovery - Screening and Design, Drug discovery - Notes and references

Read more here: » Drug discovery: Encyclopedia II - Drug discovery - Targets: New and Established

In 1965, perhaps still the most important break-through in cancer therapy occurred. James Holland, Emil Freireich, and Emil Frei hypothesized that cancer chemotherapy should follow the strategy of antibiotic therapy for tuberculosis with combinations of drugs, each with a different site of action. The cancer cells could conceivably mutate to become resistant to the a single agent, but using different drugs concurrently would make it extremely difficult for the tumor to develop resistance to the combination. They simultaneously adminis ...

See also:

History of cancer chemotherapy, History of cancer chemotherapy - The first efforts 1940–1950, History of cancer chemotherapy - Another leap forward - The antifolates, History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US, History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet, History of cancer chemotherapy - Adjuvant therapy, History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere, History of cancer chemotherapy - Zubrod's initiatives, History of cancer chemotherapy - The taxanes, History of cancer chemotherapy - The camptothecins, History of cancer chemotherapy - Platinum-based agents, History of cancer chemotherapy - Nitrosoureas, History of cancer chemotherapy - Anthracyclcines and epipodophyllotoxins, History of cancer chemotherapy - Supportive care during chemotherapy, History of cancer chemotherapy - A period of quiet, History of cancer chemotherapy - Targeted therapy, History of cancer chemotherapy - Tyrosine kinase inhibitors, History of cancer chemotherapy - Monoclonal antibodies, History of cancer chemotherapy - Concluding Comments

Read more here: » History of cancer chemotherapy: Encyclopedia II - History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet

As obviated by their origins, cancer chemotherapies are essentially poisons. Patients receiving these agents experienced severe side-effects that limited the doses which could be administered, and hence limited the beneficial effects. Clinical investigators realized that the ability to manage these toxicities was crucial to the success of cancer chemotherapy. Several examples are noteworthy. Many chemotherapeutic agents cause profound suppression of the bone marrow. This is reversible, but takes time to recover. Support with platelet ...

See also:

History of cancer chemotherapy, History of cancer chemotherapy - The first efforts 1940–1950, History of cancer chemotherapy - Another leap forward - The antifolates, History of cancer chemotherapy - 6-MP vinca alkaloids and a National Treatment Effort by the US, History of cancer chemotherapy - Combination chemotherapy the biggest break-through yet, History of cancer chemotherapy - Adjuvant therapy, History of cancer chemotherapy - Drug Discovery at the NCI and elsewhere, History of cancer chemotherapy - Zubrod's initiatives, History of cancer chemotherapy - The taxanes, History of cancer chemotherapy - The camptothecins, History of cancer chemotherapy - Platinum-based agents, History of cancer chemotherapy - Nitrosoureas, History of cancer chemotherapy - Anthracyclcines and epipodophyllotoxins, History of cancer chemotherapy - Supportive care during chemotherapy, History of cancer chemotherapy - A period of quiet, History of cancer chemotherapy - Targeted therapy, History of cancer chemotherapy - Tyrosine kinase inhibitors, History of cancer chemotherapy - Monoclonal antibodies, History of cancer chemotherapy - Concluding Comments

Read more here: » History of cancer chemotherapy: Encyclopedia II - History of cancer chemotherapy - Supportive care during chemotherapy

The writer Jack Kerouac immortalized hitchhiking in his book On The Road. The road has a fascination to Americans; countless writers have written of the road and/or hitchhiking, such as John Steinbeck, whose book The Grapes of Wrath opens with a hitched ride. Roald Dahl wrote a short story called The Hitchhiker, in which he uses the idea that you can hear fascinating stories when giving people a lift to introduce one of his trade-mark eccentric characters. Another lesser known author, a lifetime hitchhiker named Irv Thom ...

See also:

Hitchhiking, Hitchhiking - Method, Hitchhiking - Reasons, Hitchhiking - Reputation, Hitchhiking - Chances of getting a ride, Hitchhiking - Hitchhiking in literature, Hitchhiking - Safety, Hitchhiking - Crime, Hitchhiking - Road Safety, Hitchhiking - Miscellaneous

Read more here: » Hitchhiking: Encyclopedia II - Hitchhiking - Hitchhiking in literature

Hitchhiking - Crime. The safety of hitchhiking varies from country to country. In the United States, where hitchhiking had been a fairly common means to travel from one location to another well into the 1970s, especially among younger people, the practice has greatly declined in the past several decades to the point that is extremely rare to see people hitchhiking in the US today, in part because of the supposition that it is unsafe. It can also be noted that because the US has become generally more prosperous, since the mid-1980s, more people can afford to own cars and many rural areas ...

See also:

Hitchhiking, Hitchhiking - Method, Hitchhiking - Reasons, Hitchhiking - Reputation, Hitchhiking - Chances of getting a ride, Hitchhiking - Hitchhiking in literature, Hitchhiking - Safety, Hitchhiking - Crime, Hitchhiking - Road Safety, Hitchhiking - Miscellaneous

Read more here: » Hitchhiking: Encyclopedia II - Hitchhiking - Safety

Hitchhiking is often combined with other cheap forms of transportation, such as walking or travelling by bus or train. In Poland, during the communist regime period, hitchhiking was institutionalized. Many people would have a formal document for recording travels and they would give the driver confirmation that the travel occurred. Soviet Union instituted coupon system that benefited the driver. It was probably similar in other communist countries. Hitchhiking was likely considered much safer in Poland at that time. In Cuba, truck dri ...

See also:

Hitchhiking, Hitchhiking - Method, Hitchhiking - Reasons, Hitchhiking - Reputation, Hitchhiking - Chances of getting a ride, Hitchhiking - Hitchhiking in literature, Hitchhiking - Safety, Hitchhiking - Crime, Hitchhiking - Road Safety, Hitchhiking - Miscellaneous

Read more here: » Hitchhiking: Encyclopedia II - Hitchhiking - Miscellaneous