X-ray crystallography

X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, various other information. Since many materials can form crystals—such as salts, minerals, semiconductors, as well as various inorganic and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, the atomic-scale differences among various materials minerals and alloys; the method revealed the structure and function of many biological molecules, including vitamins, drugs and nucleic acids such as DNA.

X-ray crystallography is still the primary method for characterizing the atomic structure of new materials and in discerning materials that appear similar by other experiments. X-ray crystal structures can account for unusual electronic or elastic properties of a material, shed light on chemical interactions and processes, or serve as the basis for designing pharmaceuticals against diseases. In a single-crystal X-ray diffraction measurement, a crystal is mounted on a goniometer; the goniometer is used to position the crystal at selected orientations. The crystal is illuminated with a finely focused monochromatic beam of X-rays, producing a diffraction pattern of spaced spots known as reflections; the two-dimensional images taken at different orientations are converted into a three-dimensional model of the density of electrons within the crystal using the mathematical method of Fourier transforms, combined with chemical data known for the sample. Poor resolution or errors may result if the crystals are too small, or not uniform enough in their internal makeup.

X-ray crystallography is related to several other methods for determining atomic structures. Similar diffraction patterns can be produced by scattering electrons or neutrons, which are interpreted by Fourier transformation. If single crystals of sufficient size cannot be obtained, various other X-ray methods can be applied to obtain less detailed information. If the material under investigation is only available in the form of nanocrystalline powders or suffers from poor crystallinity, the methods of electron crystallography can be applied for determining the atomic structure. For all above mentioned X-ray diffraction methods, the scattering is elastic. By contrast, inelastic X-ray scattering methods are useful in studying excitations of the sample such as plasmons, crystal-field and orbital excitations and phonons, rather than the distribution of its atoms. Crystals, though long admired for their regularity and symmetry, were not investigated scientifically until the 17th century. Johannes Kepler hypothesized in his work Strena seu de Nive Sexangula that the hexagonal symmetry of snowflake crystals was due to a regular packing of spherical water particles.

The Danish scientist Nicolas Steno pioneered experimental investigations of crystal symmetry. Steno showed that the angles between the faces are the same in every exemplar of a particular type of crystal, René Just Haüy discovered that every face of a crystal can be described by simple stacking patterns of blocks of the same shape and size. Hence, William Hallowes Miller in 1839 was able to give each face a unique label of three small integers, the Miller indices which remain in use today for identifying crystal faces. Haüy's study led to the correct idea that crystals are a regular three-dimensional array of atoms and molecules. In the 19th century, a complete catalog of the possible symmetries of a crystal was worked out by Johan Hessel, Auguste Bravais, Evgraf Fedorov, Arthur Schönflies and William Barlow. From the available data and physical reasoning, Barlow proposed several crystal structures in the 1880s that were validated by X-ray crystallography. Wilhelm Röntgen discovered X-rays in 1895, just as the studies of crystal symmetry were being completed.

Physicists were uncertain of the nature of X-rays, but soon suspected that they were waves of electromagnetic radiation, a form of light. The Maxwell theory of electromagnetic radiation was well accepted among scientists, experiments by Charles Glover Barkla showed that X-rays exhibited phenomena associated with electromagnetic waves, including transverse polarization and spectral lines akin to those observed in the visible wavelengths. Single-slit experiments in the laboratory of Arnold Sommerfeld suggested that X-rays had a wavelength of about 1 angstrom. X-rays are not only waves but are photons, have particle properties. Albert Einstein introduced the photon concept in 1905, but it was not broadly accepted until 1922, when Arthur Compton confirmed it by the scattering of X-rays from electrons; the particle-like properties of X-rays, such as their ionization of gases, had prompted W

Have 'Twangy' Guitar Will Travel

Have'Twangy' Guitar Will Travel is the debut album by guitarist Duane Eddy. It was released in 1958, on Jamie Records as JLP-3000. There were five charting singles and a B-side of an additional charting single taken from this album. After releasing a couple of successful singles, Eddy released his first album, Have'Twangy' Guitar Will Travel on January 9, 1958, it is a mix of early rock & roll, swing and blues, contains several covers as well as original compositions. He and the band known as The Rebels, Al Casey on rhythm guitar, his wife Corki Casey on rhythm guitar, Steve Douglas on sax, Buddy Wheeler on bass and both Mike Bermani and Bob Taylor on drums; the album spent 82 weeks on the Billboard charts during 1959-60, reaching a high of #5. Five singles released both before and after the album was released, charted in the Billboard Hot 100. Eddy would go on to release nine more charting albums and 26 more charting singles in the next five years. Eddy and the album spawned a number of imitators such as the Rock-A-Teens, The Fabulous Wailers, The Frantics, The Fireballs and The Ventures.

All songs written by Lee Hazlewood unless noted. "Lonesome Road" – 3:09 "I Almost Lost My Mind" – 2:18 "Rebel Rouser" – 2:23 "Three-30-Blues" - 3:33 "Cannonball" – 1:55 "The Lonely One" – 1:42 "Detour" – 2:12 "Stalkin'" – 2:27 "Ramrod" – 1:42 "Anytime" – 2:19 "Moovin"N' Groovin'" – 2:05 "Loving You" – 2:10 Duane Eddy – guitar Al Casey – electric bass, rhythm guitar Steve Douglas – saxophone Corki Casey O'Dell – rhythm guitar Buddy Wheeler – electric bass Bob Taylor – drums Mike Bermani – drums Plas Johnson – saxophone Gil Bernal – saxophone Ike Clanton – bass Jimmy Simmons – upright bass Jimmy Wilcox – bass Donnie Owens – rhythm guitar The Sharps – backing vocals Lee Hazlewood – producer Lester Sill – producer Jack Miller – engineer Eddie Brackett – engineer Greg Vaughnmastering Tom Moulton – mastering Ben Demotto – liner notes

Pickled cucumber

A pickled cucumber is a cucumber, pickled in a brine, vinegar, or other solution and left to ferment for a period of time, by either immersing the cucumbers in an acidic solution or through souring by lacto-fermentation. Pickled cucumbers are part of mixed pickles, it is claimed that pickled cucumbers were first developed for workers building the Great Wall of China, though another hypothesis is that they were first made in the Tigris Valley of Mesopotamia, using cucumbers brought from India. A gherkin is a variety of cucumber: the West Indian or burr gherkin, which produces a somewhat smaller fruit than the garden cucumber. Gherkins are eaten raw, or used as pickles. Gherkins are picked when 4 to 8 cm in length and pickled in jars or cans with vinegar or brine. Sugar is a popular addition, in which case the label shows "Sweet Gherkins". In Canada, the smaller, sweeter varieties will be labelled "Gherkin." Cornichons are tart French pickles made from small gherkins pickled in tarragon. They traditionally accompany cold cuts.

Brined pickles are prepared using the traditional process of natural fermentation in a brine which makes them grow sour. The brine concentration can vary between more than 40 grams of salt per litre of water. There is no vinegar used in the brine of fermented pickled cucumbers; the fermentation process is dependent on the Lactobacillus bacteria that occur on the skin of a growing cucumber. These may be removed during commercial packing processes. Bacteria cultures can be reintroduced to the vegetables by adding fermented foods such as yogurt or other fermented milk products, pieces of sourdough bread and of course pickled vegetables such as sauerkraut. Small cucumbers are placed in a glass or ceramic vessel or a wooden barrel, together with a variety of spices. Among those traditionally used in many recipes are garlic, whole dill stems with umbels and green seeds, white mustard seeds, oak, cherry and bay laurel leaves, dried allspice fruits, and—most importantly—salt; the container is filled with cooled, boiled water and kept under a non-airtight cover for several weeks, depending on taste and external temperature.

Traditionally stones sterilized by boiling, are placed on top of the cucumbers to keep them under the water. The more salt is added the more sour the cucumbers become. Since they are produced without vinegar, a film of bacteria forms on the top, but this does not indicate they have spoiled, the film is removed, they do not, keep as long as cucumbers pickled with vinegar, must be refrigerated. Some commercial manufacturers add vinegar as a preservative. A "kosher" dill pickle is not kosher in the sense that it has been prepared in accordance with Jewish dietary law. Rather, it is a pickle made in the traditional manner of Jewish New York City pickle makers, with generous addition of garlic and dill to a natural salt brine. In New York terminology, a "full-sour" kosher dill is one that has fermented, while a "half-sour", given a shorter stay in the brine, is still crisp and bright green. Elsewhere, these pickles may sometimes be termed "old" and "new" dills. Dill pickles have been served in New York City since at least 1899.

The Polish- or German-style pickled cucumber, was developed in the northern parts of central and eastern Europe. It has been exported worldwide and is found in the cuisines of many countries, including the United States, where it was introduced by immigrants, it tends to be seasoned differently. Traditionally it was preserved in wooden barrels. A cucumber only pickled for a few days is different in taste than one pickled for a longer time and is called ogórek małosolny, which means "low-salt cucumber." This distinction is similar to the one between half- and full-sour types of kosher dills. Another kind of pickled cucumber popular in Poland is ogórek konserwowy, rather sweet and vinegary in taste, due to different composition of the preserving solution. In Hungary, while regular vinegar-pickled cucumbers are made during most of the year, during the summer kovászos uborka are made without the use of vinegar. Cucumbers are placed in a glass vessel along with spices and salt. Additionally, a slice or two of bread are placed at the top and bottom of the solution, the container is left to sit in the sun for a few days so the yeast in the bread can help cause a fermentation process.

In Romania, cucumbers are one of the vegetables used for Murături. In Korea, oi-ji is a type of jjanji. Lime pickles are soaked in pickling lime rather than in a salt brine; this is done more to enhance texture rather than as a preservative. The lime is rinsed off the pickles. Vinegar and sugar are added after the 24-hour soak in lime, along with pickling spices. Bread-and-butter pickles are a marinated pickle produced with sliced cucumbers in a solution of vinegar and spices which may be processed either by canning or chilled as refrigerator pickles