A Cleavage

[Cristoforo Kanoy]

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We thank J. Ding for recombinant protein purification and X. Wang for reagents. We thank members of the Shao laboratory for helpful discussions and technical assistance. This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB08020202), the China National Science Foundation Program for Distinguished Young Scholars (31225002) and Program for International Collaborations (31461143006), and the National Basic Research Program of China 973 Program (2012CB518700 and 2014CB849602) to F.S. The research was supported in part by an International Early Career Scientist grant from the Howard Hughes Medical Institute and the Beijing Scholar Program to F.S.

F.S. and J.S. conceived the study; J.S. performed the CRISPR-Cas9 screens; J.S. and Y.Zha. designed and performed the majority of experiments, assisted by K.W. and X. S.; H.H. and T.C. performed the deep sequencing; J.S., Y.W., Y.Zhu. and F.W. generated the knockout mice. J.S., Y.Zha. and F.S. analysed the data and wrote the manuscript. All authors discussed the results and commented on the manuscript.

This file contains figures of the uncropped immunoblots for key data presented in the main text and Extended Data sections of the manuscript. It also contains Supplementary Table 1 listing the sequences of siRNAs and primers used in the study. (PDF 1192 kb)

The GSDMD mutant was generated by replacing the FLTD site with the caspase-3 cleavage site DEVD. The mutant Flag-GSDMD was stably expressed in GSDMD-/- HeLa cells. Cells were treated with TNFα+CHX. Cells were recorded 20 min after stimulation for the duration of time indicated on the upper right corner (h : min : s: ms). Scale bar, 10 μm. Also see Fig. 4c. (MOV 8414 kb)

Cleavage, in mineralogy and materials science, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the microscope and to the naked eye. If bonds in certain directions are weaker than others, the crystal will tend to split along the weakly bonded planes. These flat breaks are termed "cleavage".[1] The classic example of cleavage is mica, which cleaves in a single direction along the basal pinacoid, making the layers seem like pages in a book. In fact, mineralogists often refer to "books of mica".

Diamond and graphite provide examples of cleavage. Each is composed solely of a single element, carbon. In diamond, each carbon atom is bonded to four others in a tetrahedral pattern with short covalent bonds. The planes of weakness (cleavage planes) in a diamond are in four directions, following the faces of the octahedron. In graphite, carbon atoms are contained in layers in a hexagonal pattern where the covalent bonds are shorter (and thus even stronger) than those of diamond. However, each layer is connected to the other with a longer and much weaker van der Waals bond. This gives graphite a single direction of cleavage, parallel to the basal pinacoid. So weak is this bond that it is broken with little force, giving graphite a slippery feel as layers shear apart. As a result, graphite makes an excellent dry lubricant.[2]

While all single crystals will show some tendency to split along atomic planes in their crystal structure, if the differences between one direction or another are not large enough, the mineral will not display cleavage. Corundum, for example, displays no cleavage.

Crystal parting occurs when minerals break along planes of structural weakness due to external stress, along twin composition planes, or along planes of weakness due to the exsolution of another mineral. Parting breaks are very similar in appearance to cleavage, but the cause is different. Cleavage occurs because of design weakness while parting results from growth defects (deviations from the basic crystallographic design). Thus, cleavage will occur in all samples of a particular mineral, while parting is only found in samples with structural defects. Examples of parting include the octahedral parting of magnetite, the rhombohedral and basal parting in corundum,[3] and the basal parting in pyroxenes.[1]

Synthetic single crystals of semiconductor materials are generally sold as thin wafers which are much easier to cleave. Simply pressing a silicon wafer against a soft surface and scratching its edge with a diamond scribe is usually enough to cause cleavage; however, when dicing a wafer to form chips, a procedure of scoring and breaking is often followed for greater control. Elemental semiconductors (silicon, germanium, and diamond) are diamond cubic, a space group for which octahedral cleavage is observed. This means that some orientations of wafer allow near-perfect rectangles to be cleaved. Most other commercial semiconductors (GaAs, InSb, etc.) can be made in the related zinc blende structure, with similar cleavage planes.

Cleavage is the narrow depression or hollow between the breasts of a woman. The superior portion of cleavage may be accentuated by clothing such as a low-cut neckline that exposes the division, and often the term is used to describe the low neckline itself, instead of the term dcolletage. Joseph Breen, head of the U.S. film industry's Production Code Administration, coined the term in its current meaning when evaluating the 1943 film The Outlaw, starring Jane Russell. The term was explained in Time magazine on August 5, 1946. It is most commonly used in the parlance of Western female fashion to refer to necklines that reveal or emphasize dcolletage (display of the upper breast area).

The visible display of cleavage can provide erotic pleasure for those who are sexually attracted to women, though this does not occur in all cultures. Explanations for this effect have included[according to whom?] evolutionary psychology, a patriarchal revolution, and dissociation from breastfeeding. Since at least the 15th century, women in the Western world have used their cleavage to flirt, attract, make political statements (such as in the Topfreedom movement), and assert power. In several parts of the world, the advent of Christianity and Islam saw a sharp decline in the amount of cleavage which was considered socially acceptable. In many cultures today,[clarification needed] cleavage exposure is considered unwelcome or is banned legally. In some areas like European beaches and among many indigenous populations across the world, cleavage exposure is acceptable; conversely, even in the Western world it is often discouraged in daywear or in public spaces. In some cases, exposed cleavage can be a target for unwanted voyeuristic photography or sexual harassment.

Cleavage-revealing clothes started becoming popular in the Christian West as it came out of the Early Middle Ages and enjoyed significant prevalence during Mid-Tang-era China, Elizabethan era England, and France over many centuries, particularly after the French Revolution. But in Victorian era England and during the flapper period of Western fashion, it was suppressed. Cleavage came vigorously back to Western fashion in the 1950s, particularly through Hollywood celebrities and lingerie brands. The consequent fascination with cleavage was most prominent in the U.S., and countries heavily influenced by the U.S. With the advent of push-up and underwired bras that replaced corsets of the past, the cleavage fascination was propelled by these lingerie manufacturers. By the early 2020s, dramatization of cleavage started to lose popularity along with the big lingerie brands. At the same time cleavage was sometimes replaced with other types of presentation of clothed breasts, like sideboobs and underboobs.

Many women enhance their cleavage through the use of things like brassires, falsies and corsetry, as well as surgical breast augmentation using saline or silicone implants and hormone therapy. Workouts, yoga, skin care, makeup, jewelry, tattoos and piercings are also used to embellish the cleavage. Male cleavage (also called heavage), accentuated by low necklines or unbuttoned shirts, is a film trend in Hollywood and Bollywood. Some men also groom their chests.

The word cleavage was first used in the early 19th century in geology and mineralogy to mean the tendency of crystals, minerals, and rocks to split along definite planes. By the mid-19th century, it was generally used to mean splitting along a line of division into two or more parts.[1][6] In the 1940s, Joseph Breen, head of the U.S. Production Code Administration, applied the term to breasts in reference to actor Jane Russell's costumes and poses in the 1943 movie The Outlaw. The term was also applied in the evaluation of the British films The Wicked Lady (1945), starring Margaret Lockwood and Patricia Roc; Bedelia (1946), also starring Lockwood; and Pink String and Sealing Wax (1945), starring Googie Withers. This use of the term was first covered in a Time article titled "Cleavage & the Code" on August 5, 1946, as a "Johnston Office (the popular name for Motion Picture Association of America office at the time[7]) trade term for the shadowed depression dividing an actress' bosom into two distinct sections."[1][2][8][9] The word cleavage is made of the root verb cleave 'to split' (from Old English clifian and Middle English clevien; cleft in the past tense) and the suffix -age 'the state of, the act of'.[6][10]

While the division of the breasts is a cleavage, the opening of a person's garments to make the division visible is called a dcolletage, a French word that is derived from dcolleter 'to reveal the neck'.[11] The term was first used in English literature before 1831[12] and was the preferred term among educated people in the English-speaking world before cleavage became the popular term.[8] Dcolletage (or dcollet in adjectival form) refers to the upper part of the female torso, consisting of the neck, shoulders, back and chest, which is exposed by the neckline, the edge of a dress or shirt that goes around the neck, especially at the front of a woman's garment.[13] The neckline and collar are often the most attention-grabbing parts of a garment, effected by bright or contrasting colors, or by dcolletage.[14][15] The term is most commonly applied to a neckline that reveals or emphasizes cleavage[16] and is measured as extending about two hand-breadths from the base of the neck down; both in the front and the back.[17] In anatomical terms, the cleft in the human body between the breasts is known as the intermammary cleft or intermammary sulcus.[18]

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