Epidermis

The epidermis is composed of the outermost layers of cells in the skin, "epi" in Greek meaning "over" or "upon", which together with the dermis forms the cutis.

The epidermis is a stratified squamous epithelium, composed of proliferating basal and differentiated suprabasal keratinocytes which acts as the body's major barrier against an inhospitable environment, by preventing pathogens from entering, making the skin a natural barrier to infection. It also regulates the amount of water released from the body into the atmosphere through transepidermal water loss (TEWL).

In humans, it is thinnest on the eyelids at 0.05 mm (0.0020 in) and thickest on the palms and soles at 1.5 mm (0.059 in). It is ectodermal in origin.

Structure

Cellular components

The epidermis is avascular, nourished almost exclusively by diffused oxygen from the surrounding air. It is 95% keratinocytes but also containing melanocytes, Langerhans cells, Merkel cells, and inflammatory cells. Rete ridges ("rete tips") are epidermal thickenings that extend downward between dermal papillae.Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule.

Skin (aeronautics)

More about the skin of aircraft covered in its wings and fuselage.

History

As the twentieth century progressed, aluminum became an essential metal in aircraft. The cylinder block of the engine that powered the Wright brothers’ plane at Kitty Hawk in 1903 was a one-piece casting in an aluminum alloy containing 8% copper; aluminum propeller blades appeared as early as 1907; and aluminum covers, seats, cowlings, cast brackets, and similar parts were common by the beginning of the First World War.

In 1916, L. Brequet designed a reconnaissance bomber that marked the initial use of aluminum in the working structure of an airplane. By war’s end, the Allies and Germany employed aluminum alloys for the structural framework of fuselage and wing assemblies.

Alloys for Airframe Components

The aircraft airframe has been the most demanding application for aluminum alloys; to chronicle the development of the high-strength alloys is also to record the development of airframes. Duralumin, the first high-strength, heat treatable aluminum alloy, was employed initially for the framework of rigid airships, by Germany and the Allies during World War I. Duralumin was an aluminum-copper-magnesium alloy; it was originated in Germany and developed in the United States as Alloy 17S-T (2017-T4). It was utilized primarily as sheet and plate. Alloy 7075-T6 (70,000-psi yield strength), an Al-Zn-Mg-Cu alloy, was introduced in 1943. Since then, most aircraft structures have been specified in alloys of this type. The first aircraft designed in 7075-T6 was the Navy’s P2V patrol bomber. A higher-strength alloy in the same series, 7178-T6 (78,000-psi yield strength), was developed in 1951; it has not generally displaced 7075-T6, which has superior fracture toughness. Alloy 7178-T6 is used primarily in structural members where performance is critical under compressive loading.

Almost Human (TV series)

Almost Human is an American science fiction/crime drama that aired from November 17, 2013, through March 3, 2014, on Fox. The series was created by J. H. Wyman for Frequency Films, Bad Robot Productions and Warner Bros. Television. Wyman, Bryan Burk and J. J. Abrams are executive producers. After one season, Fox canceled the series on April 29, 2014.

Premise

In 2048, the uncontrollable evolution of science and technology has caused crime rates to rise an astounding 400%. To combat this, the overwhelmed police force has implemented a new policy: every human police officer is paired with a lifelike combat-model android.

John Kennex (Karl Urban), a troubled detective, has a reason to hate these new robot partners. Almost two years previously, Kennex and his squad were raiding the hideout of a violent gang known as InSyndicate, but ended up being ambushed and outgunned. Kennex tried to save his badly injured partner, but the accompanying logic-based android officer abandoned them both because the wounded man's chances of survival were low and it wouldn't have been "logical" to save him. An explosion then took off Kennex's leg and killed his partner.

Skin (Rihanna song)

"Skin" is a song by Barbadian recording artist Rihanna from her fifth studio album, Loud (2010). The song was written by Kenneth Coby and Ursula Yancy, with production helmed by Soundz. Musically, "Skin" is influenced by pop, dance-pop and dubstep genres, whilst lyrically, the song is about being in a relationship with someone and only wanting to feel their skin close to the protagonists. "Skin" received generally positive reviews from critics, as part of their overall review of Loud, praising "Skin"'s compositions as well as Rihanna's sensual vocal performance. The song was included on the set list of the Loud Tour (2011), where Rihanna retrieves a man or woman from the audience near the end of the song, and performs a lap-dance whilst on an elevated platform. "Skin" was also used in Rihanna's advertisement campaign for Armani Jeans.

Background and composition