Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. Overview Atomic force microscopy (AFM) is a type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. The information is gathered by "feeling" or "touching" the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable precise scanning. Despite the name, the Atomic Force Microscope does not use the Nuclear force. Abilities The AFM has three major abilities: force measurement, topographic imaging, and manipulation. In force measurement, AFMs can be used to measure the forces between the probe and the sample as a function of their mutual separation. This can be applied to perform force spectroscopy...

In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The function of TFs is to regulate—turn on and off—genes in order to make sure that they are expressed in the desired cells at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are 1500-1600 TFs in the human genome. Transcription factors are members of the proteome as well as regulome. TFs work alone or with other proteins in a complex, by promoting (as an activator), or blocking (as a repressor) the recruitment of RNA polymerase (the enzyme that performs the transcription of genetic information from DNA to RNA) to specific genes.A defining feature of TFs is that they contain...

In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. The interstellar medium is composed of multiple phases distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the matter. The interstellar medium is composed, primarily, of hydrogen, followed by helium with trace amounts of carbon, oxygen, and nitrogen. The thermal pressures of these phases are in rough equilibrium with one another. Magnetic fields and turbulent motions also provide pressure in the ISM, and are typically more important, dynamically, than the thermal pressure is. In the interstellar medium, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the...

Merrick Brian Garland (born November 13, 1952) is an American lawyer and jurist serving since March 2021 as the 86th United States attorney general. He previously served as a U.S. circuit judge of the U.S. Court of Appeals for the District of Columbia Circuit from 1997 to 2021. A native of the Chicago area, Garland attended Harvard University for his undergraduate and legal education. After serving as a law clerk to Judge Henry J. Friendly of the Court of Appeals for the Second Circuit and Supreme Court Justice William J. Brennan Jr., he practiced corporate litigation at Arnold & Porter and worked as a federal prosecutor in the Department of Justice, where he played a leading role in the investigation and prosecution of the Oklahoma City bombers. Garland was appointed to the D.C. Circuit in March 1997 by President Bill Clinton, and served as its chief judge from 2013 to 2020. President Barack Obama, a Democrat, nominated Garland to serve as an associate justice of the Supreme Court in March 2016 to fill the vacancy created by the death of Antonin Scalia. However, the Republican Senate majority refused to hold a hearing or vote...

Up, up, and away! Paper airplanes are a fun, easy way to pass the time—but how exactly do you turn a basic piece of paper into a jet-setting masterpiece? You've come to the right place. We've put together a handy, step-by-step guide to...

Kallanai (also known as the Grand Anicut) is an ancient dam built by Karikala of Chola dynasty in 150 CE. It is built (in running water) across the Kaveri river flowing from Tiruchirapalli District to Thanjavur district, Tamil Nadu, India. The dam located in Thanjavur district. Located at a distance of 15 km from Tiruchirapalli, 45 km from Tanjavur. It is the fourth oldest water diversion or water-regulator structures in the world and the oldest in India that is still in use. Because of its spectacular architecture, it is one of the prime tourist spots in Tamil Nadu. History The dam was originally built by King Karikalan of the Chola Dynasty in c. 100  – c. 150 CE. It is located on the river in Thanjavur district, exactly 14 km from the city of Tiruchirappalli and 45 km from the city of Thanjavur. The idea behind the construction of the dam was to divert the river to the delta districts thereby boosting irrigation. This dam was re-modeled by the British during the 19th century. In 1804, Captain Caldwell, a military engineer, was appointed...

What is a space probe?

Sir Winston Leonard Spencer Churchill (30 November 1874 – 24 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from 1951 to 1955. Apart from two years between 1922 and 1924, he was a Member of Parliament (MP) from 1900 to 1964 and represented a total of five constituencies. Ideologically an economic liberal and imperialist, he was for most of his career a member of the Conservative Party, which he led from 1940 to 1955. He was a member of the Liberal Party from 1904 to 1924. Of mixed English and American parentage, Churchill was born in Oxfordshire to a wealthy, aristocratic family. He joined the British Army in 1895 and saw action in British India, the Anglo-Sudan War, and the Second Boer War, gaining fame as a war correspondent and writing books about his campaigns. Elected a Conservative MP in 1900, he defected to the Liberals in 1904. In H. H. Asquith's Liberal government, Churchill served as President of the Board of Trade and...

The Salic law ( or ; Latin: Lex salica), also called the Salian law, was the ancient Frankish civil law code compiled around AD 500 by the first Frankish King, Clovis. The written text is in Latin and contains some of the earliest known instances of Old Dutch. It remained the basis of Frankish law throughout the early Medieval period, and influenced future European legal systems. The best-known tenet of the old law is the principle of exclusion of women from inheritance of thrones, fiefs, and other property. The Salic laws were arbitrated by a committee appointed and empowered by the King of the Franks. Dozens of manuscripts dating from the sixth to eighth centuries and three emendations as late as the ninth century have survived.Salic law provided written codification of both civil law, such as the statutes governing inheritance, and criminal law, such as the punishment for murder. Although it was originally intended as the law of the Franks, it has had a formative influence on the tradition of statute law that extended to modern history in much of Europe, especially in the German states and Austria-Hungary...