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Bacterial capsule
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It has been suggested that Polysaccharide encapsulated bacteria be merged into this article. (Discuss) Proposed since November 2017.
The outer red layer in this diagram is the capsule, which is distinct from the cell envelope. This bacteria is gram-positive, as its cell envelope comprises a single cell membrane (orange) and a thick peptidoglycan containing cell wall (purple).
The bacterial capsule is a very large structure of many bacteria.[1] It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
The capsule—which can be found in both gram negative and gram-positive bacteria—is different to the second lipid membrane – bacterial outer membrane, which contains lipopolysaccharides and lipoproteins and is found only in gram-negative bacteria. When the amorphous viscid secretion (that makes up the capsule) diffuses into the surrounding medium and remains as a loose undemarcated secretion, it is known as slime layer.
A bacterial capsule has a semi-ridged border that follows the contour of the cell. The capsule excludes India Ink when dyed. A slime layer is a non-ridged matrix that is easily deformed and is not able to exclude India Ink. Biofilms are composed of many cells and their outer barriers. The primary functions of both capsules and slime layers are for protection and adhesion.
Contents
[hide]
1 Composition
2 Function
3 Diversity
4 Demonstration of capsule
5 Use in vaccination
6 See also
7 References
Composition[edit]
It usually consists of polysaccharides,[2] but can be composed of other materials such as polypeptide D-glutamic acid in B. anthracis, and peptidoglycan and muramic acid found in E.coli bacterial capsule. Because most capsules are so tightly packed, they are difficult to stain because most standard stains cannot adhere to the capsule. For examination under the microscope, the bacteria and their background are stained darker than the capsule, which doesn't stain. When viewed, bacterial cells as well as the surface they are on, are stained dark, while the capsule remains pale or colorless and appears as a ring, or halo, around the cell.[3]
Function[edit]
The capsule is considered a virulence factor because it enhances the ability of bacteria to cause disease (e.g. prevents phagocytosis). The capsule can protect cells from engulfment by eukaryotic cells, such as macrophages.[4] A capsule-specific antibody may be required for phagocytosis to occur. Capsules also contain water which protects the bacteria against desiccation. They also exclude bacterial viruses and most hydrophobic toxic materials such as detergents.[citation needed] Immunity to one capsule type does not result in immunity to the other types. Capsules also help cells adhere to surfaces.
Diversity[edit]
The capsule is found most commonly among gram-negative bacteria:
Escherichia coli (in some strains)
Neisseria meningitidis[5]
Klebsiella pneumoniae[6]
Haemophilus influenzae[7]
Pseudomonas aeruginosa[8]
Salmonella[citation needed]
However, some gram-positive bacteria may also have a capsule:
Bacillus megaterium for example, synthesizes a capsule composed of polypeptide and polysaccharides.
Streptococcus pyogenes synthesizes a hyaluronic acid capsule.
Streptococcus pneumoniae has at least 91 different capsular serotypes.[9] These serotypes are the basis for the pneumococcal vaccines.
Streptococcus agalactiae produces a polysaccharide capsule of nine antigenic types that all contain sialic acid (Ia, Ib, II, III, IV, V, VI, VII, VIII).
Staphylococcus epidermidis
The yeast Cryptococcus neoformans, though not a bacterium, has a similar capsule.[10]
Capsules too small to be seen with an ordinary microscope, such as the M protein of Streptococcus pyogenes, are called microcapsules.
Demonstration of capsule[edit]
India ink staining: the capsule appears as a clear halo around the bacterium as the ink can't penetrate the capsule.[11]:87
Maneval's capsule stain: the capsule appears as a clear halo between the pink-stained bacterium and the bluish-grey stained background. The background stain is the acidic stain Congo red (which changes color to bluish-grey due to the pH), and the pink stain is acid fuschin.
Serological methods: Capsular material is antigenic and can be demonstrated by mixing it with a specific anticapsular serum. When examined under the microscope, the capsule appears 'swollen' due to an increase in its refractivity. This phenomenon is the basis of Quellung reaction.
Use in vaccination[edit]
Vaccination using capsular material is effective against some organisms (e.g., H. influenzae type b, S. pneumoniae, and N. meningitidis). However, polysaccharides are not highly antigenic, especially in children, so many capsular vaccines contain polysaccharides conjugated with protein carriers, such as the tetanus toxoid or diphtheria toxoid. This stimulates a much more robust immune response.[12]
See also[edit]
Bacterial cell structure
Quellung reaction, a method to visualize capsule under a microscope
References[edit]
Jump up ^ Peterson, Johnny W. (1996). "Bacterial Pathogenesis". Medical Microbiology. University of Texas Medical Branch at Galveston. Retrieved 17 January 2018.
Jump up ^ "bacterial capsule" at Dorland's Medical Dictionary
Jump up ^ Encyclopædia Britannica [Capsules and Slime Layers].
Jump up ^ Daffé, M.; Etienne, G. (1999). "The capsule of Mycobacterium tuberculosis and its implications for pathogenicity". Tubercle and Lung Disease. 79 (3): 153–69. doi:10.1054/tuld.1998.0200. PMID 10656114.
Jump up ^ "Meningococcal meningitis". Textbookofbacteriology.net. Archived from the original on 2014-02-09. Retrieved 2014-01-22.
Jump up ^ Yoshida, K; Matsumoto, T; Tateda, K; Uchida, K; Tsujimoto, S; Yamaguchi, K (November 2000). "Role of bacterial capsule in local and systemic inflammatory responses of mice during pulmonary infection with Klebsiella pneumoniae". Journal of Medical Microbiology. 49 (11): 1003–10. doi:10.1099/0022-1317-49-11-1003. PMID 11073154.
Jump up ^ Schouls, Leo; Van Der Heide, Han; Witteveen, Sandra; Zomer, Bert; Van Der Ende, Arie; Burger, Marina; Schot, Corrie (2008). "Two variants among Haemophilus influenzae serotype b strains with distinct bcs4, hcsA and hcsB genes display differences in expression of the polysaccharide capsule". BMC Microbiology. 8 (1): 35. doi:10.1186/1471-2180-8-35. PMC 2267795  . PMID 18298818.
Jump up ^ Deretic, V; Dikshit, R; Konyecsni, WM; Chakrabarty, AM; Misra, TK (1989). "The algR gene, which regulates mucoidy in Pseudomonas aeruginosa, belongs to a class of environmentally responsive genes". Journal of Bacteriology. 171 (3): 1278–1283. PMC 209741  . PMID 2493441.
Jump up ^ Hyams, Catherine; Camberlein, Emilie; Cohen, Jonathan M.; Bax, Katie; Brown, Jeremy S. (2010-02-01). "The Streptococcus pneumoniae Capsule Inhibits Complement Activity and Neutrophil Phagocytosis by Multiple Mechanisms". Infection and Immunity. 78 (2): 704–715. doi:10.1128/IAI.00881-09. ISSN 0019-9567. PMC 2812187  . PMID 19948837.
Jump up ^ Gates, Marcellene A.; Thorkildson, Peter; Kozel, Thomas R. (April 1390). "Molecular architecture of the Cryptococcus neoformans capsule". Molecular Microbiology. 52 (1): 13–24. doi:10.1111/j.1365-2958.2003.03957.x. PMID 15049807.
Jump up ^ Prokaryotes. Newnes. April 11, 1996. ISBN 978-0-08-098473-5.
Jump up ^ Goldblatt, D (2000-01-01). "Conjugate vaccines". Clinical and Experimental Immunology. 119 (1): 1–3. doi:10.1046/j.1365-2249.2000.01109.x. ISSN 0009-9104. PMC 1905528  . PMID 10671089.
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Lesley Fera
From Wikipedia, the free encyclopedia
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Lesley Fera
Born
(1971-11-23) November 23, 1971 (age 46) [1]
Nationality
American
Occupation
Actress
Years active
1998–present
Lesley Fera (born November 23, 1971) is an American actress. She is best known for her role as Veronica Hastings on the ABC Family series Pretty Little Liars.[2] Fera also had a recurring roles in 24, CSI: Miami and Southland, as well as performing in a number of theater productions.[2]
Contents
[hide]
1 Biography
2 Filmography
2.1 Film
2.2 Television
2.3 Stage
3 References
4 External links
Biography[edit]
A native Californian, Lesley is a lover of the stage, she is very active in L.A. theatre and has also enjoyed working at numerous regional theaters.

Filmography[edit]
Film[edit]
Year
Title
Role
Notes
2005 Herstory Marly
2017 The Lovers Susan
2017 Boone: The Bounty Hunter Madam Sylvia
Television[edit]
Year
Title
Role
Notes
1998 3rd Rock from the Sun Woman #2 "The Great Dickdater" (season 3: episode 13)
1999 Absence of the Good Beth Television film
2000 Titus Paula "Sex with Pudding" (season 1: episode 1)
2001 Gideon's Crossing Janet Beckman "The Crash" (season 1: episode 19)
2001 Strong Medicine Anne "Impaired" (season 2: episode 7)
2001 Thieves Carla Patterson "Home Is Where the Heist Is…" (season 1: episode 10)
2001 The Drew Carey Show Judy "Bus-ted" (season 7: episode 6)
2001 Citizen Baines Eileen McGuire "Out in the Rain" (season 1: episode 7)
2002 Judging Amy Mrs. Moran "Picture of Perfect" (season 4: episode 21)
2003 The Practice A.D.A. Kate Barron "We the People" (season 8: episode 1)
2004–10 CSI: Miami Dr. Joyce Carmel 4 episodes
Guest star (Seasons 2, 4, 5, 9)
2004 ER Helen Kolber "NICU" (season 10: episode 12)
2004 Medical Investigation Gladys Halperin "Coming Home" (season 1: episode 3)
2005 NYPD Blue Debra Campo "Sergeant Sipowicz' Lonely Hearts Club Band" (season:12 episode 17)
2006 Numb3rs ATF Agent Annie Wilson "Guns and Roses" (season 2: episode 20)
2006 Cold Case Dana Taylor '04 "The War at Home" (season 4: episode 2)
2006–07 Justice DA Jennifer Reese 2 episodes
2009–10 24 Angela Nelson 6 episodes
Recurring role (Season 7) Guest Star (Season 8)
2009 Without a Trace Cynthia "Heartbeats" (season 7: episode 19)
2009 The Mentalist Leslie Sloop "Throwing Fire" (season 2: episode 10)
2010 Nip/Tuck Daniella Creighton "Christian Troy II" (season 6: episode 17)
2010 Criminal Minds Leslie McBride "The Fight" (season 5: episode 18)
2010–17 Pretty Little Liars Veronica Hastings 53 episodes;
Recurring role (Seasons 1–7)
2010 Detroit 1-8-7 Dr. Maya Ehrlich "Shelter" (Season 1: episode 10)
2011 House M.D. Kay "Bombshells" (Season 7: episode 15)
2013 Southland Sergeant Waters 4 episodes
Recurring role (Season 5)
2013 Dating in LA and Other Urban Myths Penelope 9 episodes
Main role (Season 1)
2014 Stalker Mrs. McCoy "Whatever Happened to Baby James?" (Season 1: episode 2)
2017 Battle of the Network Stars Herself Contestant
Stage[edit]
Year
Title
Role
Location
1995–96 Noises Off Poppy Asolo Repertory Theatre
1996 The Life and Adventures of Nicholas Nickleby Miss Knag (et al)
1997 The Children’s Hour Martha Provincetown Theater Foundation
1997 The Mousetrap Mollie Pennsylvania Centre Stage
1997 Misalliance Hypatia
1998 A Sense of Place Mary Tate American Stage
1999 Communicating Doors Poopay / Phoebe San Jose Repertory Theatre
2000–01 Lady Chatterley’s Lover Lady Chatterley Pacific Resident Theatre
2002 Anna Christie Anna Christie
2002–03 Big Love Olympia
2004 Dealing With Clair The Matrix Theatre Company
2005 Happy End Lillian Holiday Pacific Resident Theatre
2007 The Hasty Heart Margaret
2011 Barrie: Back to Back Mrs. Beatrice Page
2012 Our Town The Eli and Edythe Broad Stage
2015 The Homecoming Ruth Pacific Resident Theatre
2016 Two Dollar Bill Jessica McGovern Pioneer Theatre Company
2016 Bull Isobel Rogue Machine Theatre
2016 Two Henrys Pacific Resident Theatre
2017 Dinner with Friends
References[edit]
Jump up ^ "My birthday cake! :)". Twitter. Retrieved 2015-08-03.
^ Jump up to: a b "Veronica Hastings by Lesley Fera - Pretty Little Liars - ABCFamily.com". Abcfamily.go.com. Retrieved 2014-06-03.
External links[edit]
Lesley Fera on IMDb

This article about an American television actor or actress is a stub. You can help Wikipedia by expanding it.
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Second messenger system
From Wikipedia, the free encyclopedia
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Second messengers are intracellular signaling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Secondary messengers are therefore one of the initiating components of intracellular signal transduction cascades. Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol trisphosphate, diacylglycerol, and calcium. The cell releases second messenger molecules in response to exposure to extracellular signaling molecules—the first messengers. First messengers are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin. Because peptide hormones and neurotransmitters typically are biochemically hydrophilic molecules, these first messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly—unlike steroid hormones, which usually do. This functional limitation necessitates the cell to devise signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly. An important feature of the second messenger signaling system is that second messengers may be coupled downstream to multi-cyclic kinase cascades to greatly amplify the strength of the original first messenger signal.[1][2] For example, RasGTP signals link with the Mitogen Activated Protein Kinase (MAPK) cascade to amplify the allosteric activation of proliferative transcription factors such as Myc and CREB.
Earl Wilbur Sutherland, Jr., discovered second messengers, for which he won the 1971 Nobel Prize in Physiology or Medicine. Sutherland saw that epinephrine would stimulate the liver to convert glycogen to glucose (sugar) in liver cells, but epinephrine alone would not convert glycogen to glucose. He found that epinephrine had to trigger a second messenger, cyclic AMP, for the liver to convert glycogen to glucose.[3] The mechanisms were worked out in detail[4][5] by Martin Rodbell and Alfred G. Gilman, who won the 1994 Nobel prize.
Secondary messenger systems can be synthesized and activated by enzymes, for example, the cyclases that synthesize cyclic nucleotides, or by opening of ion channels to allow influx of metal ions, for example Ca2+ signaling. These small molecules bind and activate protein kinases, ion channels, and other proteins, thus continuing the signaling cascade.
Contents
[hide]
1 Types of second messenger molecules
2 Common mechanisms of second messenger systems
3 Examples
4 References
5 External links
Types of second messenger molecules[edit]
There are three basic types of secondary messenger molecules:
Hydrophobic molecules: water-insoluble molecules such as diacylglycerol, and phosphatidylinositols, which are membrane-associated and diffuse from the plasma membrane into the intermembrane space where they can reach and regulate membrane-associated effector proteins
Hydrophilic molecules: water-soluble molecules, such as cAMP, cGMP, IP3, and Ca2+, that are located within the cytosol
Gases: nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) which can diffuse both through cytosol and across cellular membranes.
These intracellular messengers have some properties in common:
They can be synthesized/released and broken down again in specific reactions by enzymes or ion channels.
Some (such as Ca2+) can be stored in special organelles and quickly released when needed.
Their production/release and destruction can be localized, enabling the cell to limit space and time of signal activity.
Common mechanisms of second messenger systems[edit]
General Schematic of Second Messenger Mechanism
There are several different secondary messenger systems (cAMP system, phosphoinositol system, and arachidonic acid system), but they all are quite similar in overall mechanism, although the substances involved and overall effects can vary.
In most cases, a ligand binds to a membrane-spanning receptor protein molecule. The binding of a ligand to the receptor causes a conformation change in the receptor. This conformation change can affect the activity of the receptor and result in the production of active second messages.
In the case of G protein-coupled receptors, the conformation change exposes a binding site for a G-protein. The G-protein (named for the GDP and GTP molecules that bind to it) is bound to the inner membrane of the cell and consists of three subunits: alpha, beta and gamma. The G-protein is known as the "transducer."
When the G-protein binds with the receptor, it becomes able to exchange a GDP (guanosine diphosphate) molecule on its alpha subunit for a GTP (guanosine triphosphate) molecule. Once this exchange takes place, the alpha subunit of the G-protein transducer breaks free from the beta and gamma subunits, all parts remaining membrane-bound. The alpha subunit, now free to move along the inner membrane, eventually contacts another membrane-bound protein - the "primary effector."
The primary effector then has an action, which creates a signal that can diffuse within the cell. This signal is called the "second (or secondary) messenger." The secondary messenger may then activate a "secondary effector" whose effects depend on the particular secondary messenger system.
Calcium ions are one type of second messengers and are responsible for many important physiological functions including muscle contraction, fertilization and neurotransmitter release. The ions are normally bound or stored in intracellular components (such as the endoplasmic reticulum) and can be released during signal transduction. The enzyme phospholipase C produces diacylglycerol and inositol trisphosphate, which increases calcium ion permeability into the membrane. Active G-protein open up calcium channels to let calcium ions enter the plasma membrane. The other product of phospholipase C, diacylglycerol, activates protein kinase C, which assists in the activation of cAMP (another second messenger).
Examples[edit]
cAMP System Phosphoinositol system Arachidonic acid system cGMP System Tyrosine kinase system
First Messenger:
Neurotransmitters
(Receptor) Epinephrine (α2, β1, β2)
Acetylcholine (M2) Epinephrine (α1)
Acetylcholine (M1, M3) Histamine (Histamine receptor) - -
First Messenger:
Hormones ACTH, ANP, CRH, CT, FSH, Glucagon, hCG, LH, MSH, PTH, TSH AGT, GnRH, GHRH, Oxytocin, TRH - ANP, Nitric oxide INS, IGF, PDGF
Signal Transducer GPCR/Gs (β1, β2), Gi (α2, M2) GPCR/Gq Unknown G-protein - RTK
Primary effector Adenylyl cyclase Phospholipase C Phospholipase A guanylate cyclase RasGEF (Grb2-Sos)
Second messenger cAMP (cyclic adenosine monophosphate) IP3; DAG; Ca2+ Arachidonic acid cGMP Ras.GTP (Small G Protein)
Secondary effector protein kinase A PKC; CaM 5-Lipoxygenase, 12-Lipoxygenase, cycloxygenase protein kinase G MAP3K (c-Raf)
References[edit]
Jump up ^ Kimball, J. "Second messengers".
Jump up ^ Second Messenger Systems at the US National Library of Medicine Medical Subject Headings (MeSH)
Jump up ^ Reece, Jane; Campbell, Neil (2002). Biology. San Francisco: Benjamin Cummings. ISBN 0-8053-6624-5.
Jump up ^ The Discovery of G Proteins
Jump up ^ Signal Transduction in Cells, Nobelprize.org
External links[edit]
Kimball, J. "Second messengers". Retrieved February 10, 2006.
Animation: Second Messenger: cAMP
[show]
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t
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Cell physiology: Cell signaling / Signal transduction
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Electron shell
From Wikipedia, the free encyclopedia
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In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the "1 shell" (also called "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers (n = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, …).
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.[1] Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even three incomplete outer shells. (See Madelung rule for more details.) For an explanation of why electrons exist in these shells see electron configuration.[2]
The electrons in the outermost occupied shell (or shells) determine the chemical properties of the atom; it is called the valence shell.
Each shell consists of one or more subshells, and each subshell consists of one or more atomic orbitals.
Contents
1 History
2 Shells
3 Subshells
4 Number of electrons in each shell
5 Valence shell
6 List of elements with electrons per shell
7 See also
8 References
History
The shell terminology comes from Arnold Sommerfeld's modification of the Bohr model. Sommerfeld retained Bohr's planetary model, but added mildly elliptical orbits (characterized by additional quantum numbers ℓ and m) to explain the fine spectroscopic structure of some elements.[3] The multiple electrons with the same principal quantum number (n) had close orbits that formed a "shell" of positive thickness instead of the infinitely thin circular orbit of Bohr's model.
The existence of electron shells was first observed experimentally in Charles Barkla's and Henry Moseley's X-ray absorption studies. Barkla labeled them with the letters K, L, M, N, O, P, and Q.[4] The origin of this terminology was alphabetic. A "J" series was also suspected, though later experiments indicated that the K absorption lines are produced by the innermost electrons. These letters were later found to correspond to the n values 1, 2, 3, etc. They are used in the spectroscopic Siegbahn notation.
The physical chemist Gilbert Lewis was responsible for much of the early development of the theory of the participation of valence shell electrons in chemical bonding. Linus Pauling later generalized and extended the theory while applying insights from quantum mechanics.
Shells
The electron shells are labeled K, L, M, N, O, P, and Q; or 1, 2, 3, 4, 5, 6, and 7; going from innermost shell outwards. Electrons in outer shells have higher average energy and travel farther from the nucleus than those in inner shells. This makes them more important in determining how the atom reacts chemically and behaves as a conductor, because the pull of the atom's nucleus upon them is weaker and more easily broken. In this way, a given element's reactivity is highly dependent upon its electronic configuration.
Subshells
Each shell is composed of one or more subshells, which are themselves composed of atomic orbitals. For example, the first (K) shell has one subshell, called 1s; the second (L) shell has two subshells, called 2s and 2p; the third shell has 3s, 3p, and 3d; the fourth shell has 4s, 4p, 4d and 4f; the fifth shell has 5s, 5p, 5d, and 5f and can theoretically hold more but the 5f subshell, although partially occupied in actinides, is not filled in any element occurring naturally.[2] The various possible subshells are shown in the following table:
Subshell label
ℓ
Max electrons
Shells containing it
Historical name
s 0 2 Every shell sharp
p 1 6 2nd shell and higher principal
d 2 10 3rd shell and higher diffuse
f 3 14 4th shell and higher fundamental
g 4 18 5th shell and higher (theoretically) (next in alphabet after f, excluding j)[5]
The first column is the "subshell label", a lowercase-letter label for the type of subshell. For example, the "4s subshell" is a subshell of the fourth (N) shell, with the type (s) described in the first row.
The second column is the azimuthal quantum number (ℓ) of the subshell. The precise definition involves quantum mechanics, but it is a number that characterizes the subshell.
The third column is the maximum number of electrons that can be put into a subshell of that type. For example, the top row says that each s-type subshell (1s, 2s, etc.) can have at most two electrons in it. In each case the figure is 4 greater than the one above it.
The fourth column says which shells have a subshell of that type. For example, looking at the top two rows, every shell has an s subshell, while only the second shell and higher have a p subshell (i.e., there is no "1p" subshell).
The final column gives the historical origin of the labels s, p, d, and f. They come from early studies of atomic spectral lines. The other labels, namely g, h and i, are an alphabetic continuation following the last historically originated label of f.
Although it is commonly stated that all the electrons in a shell have the same energy, this is an approximation. However, the electrons in one subshell do have exactly the same level of energy,[6] with later subshells having more energy per electron than earlier ones. This effect is great enough that the energy ranges associated with shells can overlap (see valence shells and Aufbau principle).
Number of electrons in each shell
Shells and subshells. 1 rectangular triangle (1/2 of a cell) = 1 electron on the level. Red color indicates sublevel s; orange - p; yellow - d; green - f; blue - g; indigo - h; violet - i
Shell
name
Subshell
name
Subshell
max
electrons
Shell
max
electrons
K 1s 2 2
L 2s 2 2 + 6 = 8
2p 6
M 3s 2 2 + 6 + 10
= 18
3p 6
3d 10
N 4s 2 2 + 6 +
10 + 14
= 32
4p 6
4d 10
4f 14
O 5s 2 2 + 6 +
10 + 14 +
18 = 50
5p 6
5d 10
5f 14
5g 18
Each subshell is constrained to hold 4ℓ + 2 electrons at most, namely:
Each s subshell holds at most 2 electrons
Each p subshell holds at most 6 electrons
Each d subshell holds at most 10 electrons
Each f subshell holds at most 14 electrons
Each g subshell holds at most 18 electrons
Therefore, the K shell, which contains only an s subshell, can hold up to 2 electrons; the L shell, which contains an s and a p, can hold up to 2 + 6 = 8 electrons, and so forth; in general, the nth shell can hold up to 2n2 electrons.[1]
Although that formula gives the maximum in principle, in fact that maximum is only achieved (by known elements) for the first four shells (K, L, M, N). No known element has more than 32 electrons in any one shell.[7][8] This is because the subshells are filled according to the Aufbau principle. The first elements to have more than 32 electrons in one shell would belong to the g-block of period 8 of the periodic table. These elements would have some electrons in their 5g subshell and thus have more than 32 electrons in the O shell (fifth principal shell).
Valence shell
See also: Valence electron
The valence shell is the outermost shell of an atom. Valence electrons in non-transition metal elements reside in this shell. Such elements with complete valence shells (noble gases) are the most chemically non-reactive, while those with only one electron in their valence shells (alkali metals) or just missing one electron from having a complete shell (halogens) are the most reactive.[9]
However, this terminology is somewhat misleading in the case of transition metals. In these elements, a valence electron can also be in an inner shell. Thus, the electrons that determine how an atom reacts chemically are those that travel farthest from the nucleus, that is, those with the highest energy, and not necessarily in the valence shell.
List of elements with electrons per shell
The list below gives the elements arranged by increasing atomic number and shows the number of electrons per shell. At a glance, one can see that subsets of the list show obvious patterns. In particular, the seven elements (in electric blue) before a noble gas (group 18, in yellow) higher than helium have the number of electrons in the valence shell in arithmetic progression. (However, this pattern may break down in the seventh period due to relativistic effects.)
Sorting the table by chemical group shows additional patterns, especially with respect to the last two outermost shells. (Elements 57 to 71 belong to the lanthanides, while 89 to 103 are the actinides.)
The list below is primarily consistent with the Aufbau principle. However, there are a number of exceptions to the rule; for example palladium (atomic number 46) has no electrons in the fifth shell, unlike other atoms with lower atomic number. Some entries in the table are uncertain, when experimental data is unavailable. (For example, the elements past 108 have such short half-lives that their electron configurations have not yet been measured.)
Z
Element
No. of electrons/shell
Group
1 Hydrogen 1 1
2 Helium 2 18
3 Lithium 2, 1 1
4 Beryllium 2, 2 2
5 Boron 2, 3 13
6 Carbon 2, 4 14
7 Nitrogen 2, 5 15
8 Oxygen 2, 6 16
9 Fluorine 2, 7 17
10 Neon 2, 8 18
11 Sodium 2, 8, 1 1
12 Magnesium 2, 8, 2 2
13 Aluminium 2, 8, 3 13
14 Silicon 2, 8, 4 14
15 Phosphorus 2, 8, 5 15
16 Sulfur 2, 8, 6 16
17 Chlorine 2, 8, 7 17
18 Argon 2, 8, 8 18
19 Potassium 2, 8, 8, 1 1
20 Calcium 2, 8, 8, 2 2
21 Scandium 2, 8, 9, 2 3
22 Titanium 2, 8, 10, 2 4
23 Vanadium 2, 8, 11, 2 5
24 Chromium 2, 8, 13, 1 6
25 Manganese 2, 8, 13, 2 7
26 Iron 2, 8, 14, 2 8
27 Cobalt 2, 8, 15, 2 9
28 Nickel 2, 8, 16, 2 10
29 Copper 2, 8, 18, 1 11
30 Zinc 2, 8, 18, 2 12
31 Gallium 2, 8, 18, 3 13
32 Germanium 2, 8, 18, 4 14
33 Arsenic 2, 8, 18, 5 15
34 Selenium 2, 8, 18, 6 16
35 Bromine 2, 8, 18, 7 17
36 Krypton 2, 8, 18, 8 18
37 Rubidium 2, 8, 18, 8, 1 1
38 Strontium 2, 8, 18, 8, 2 2
39 Yttrium 2, 8, 18, 9, 2 3
40 Zirconium 2, 8, 18, 10, 2 4
41 Niobium 2, 8, 18, 12, 1 5
42 Molybdenum 2, 8, 18, 13, 1 6
43 Technetium 2, 8, 18, 13, 2 7
44 Ruthenium 2, 8, 18, 15, 1 8
45 Rhodium 2, 8, 18, 16, 1 9
46 Palladium 2, 8, 18, 18 10
47 Silver 2, 8, 18, 18, 1 11
48 Cadmium 2, 8, 18, 18, 2 12
49 Indium 2, 8, 18, 18, 3 13
50 Tin 2, 8, 18, 18, 4 14
51 Antimony 2, 8, 18, 18, 5 15
52 Tellurium 2, 8, 18, 18, 6 16
53 Iodine 2, 8, 18, 18, 7 17
54 Xenon 2, 8, 18, 18, 8 18
55 Caesium 2, 8, 18, 18, 8, 1 1
56 Barium 2, 8, 18, 18, 8, 2 2
57 Lanthanum 2, 8, 18, 18, 9, 2 3
58 Cerium 2, 8, 18, 19, 9, 2
59 Praseodymium 2, 8, 18, 21, 8, 2
60 Neodymium 2, 8, 18, 22, 8, 2
61 Promethium 2, 8, 18, 23, 8, 2
62 Samarium 2, 8, 18, 24, 8, 2
63 Europium 2, 8, 18, 25, 8, 2
64 Gadolinium 2, 8, 18, 25, 9, 2
65 Terbium 2, 8, 18, 27, 8, 2
66 Dysprosium 2, 8, 18, 28, 8, 2
67 Holmium 2, 8, 18, 29, 8, 2
68 Erbium 2, 8, 18, 30, 8, 2
69 Thulium 2, 8, 18, 31, 8, 2
70 Ytterbium 2, 8, 18, 32, 8, 2
71 Lutetium 2, 8, 18, 32, 9, 2
72 Hafnium 2, 8, 18, 32, 10, 2 4
73 Tantalum 2, 8, 18, 32, 11, 2 5
74 Tungsten 2, 8, 18, 32, 12, 2 6
75 Rhenium 2, 8, 18, 32, 13, 2 7
76 Osmium 2, 8, 18, 32, 14, 2 8
77 Iridium 2, 8, 18, 32, 15, 2 9
78 Platinum 2, 8, 18, 32, 17, 1 10
79 Gold 2, 8, 18, 32, 18, 1 11
80 Mercury 2, 8, 18, 32, 18, 2 12
81 Thallium 2, 8, 18, 32, 18, 3 13
82 Lead 2, 8, 18, 32, 18, 4 14
83 Bismuth 2, 8, 18, 32, 18, 5 15
84 Polonium 2, 8, 18, 32, 18, 6 16
85 Astatine 2, 8, 18, 32, 18, 7 17
86 Radon 2, 8, 18, 32, 18, 8 18
87 Francium 2, 8, 18, 32, 18, 8, 1 1
88 Radium 2, 8, 18, 32, 18, 8, 2 2
89 Actinium 2, 8, 18, 32, 18, 9, 2 3
90 Thorium 2, 8, 18, 32, 18, 10, 2
91 Protactinium 2, 8, 18, 32, 20, 9, 2
92 Uranium 2, 8, 18, 32, 21, 9, 2
93 Neptunium 2, 8, 18, 32, 22, 9, 2
94 Plutonium 2, 8, 18, 32, 24, 8, 2
95 Americium 2, 8, 18, 32, 25, 8, 2
96 Curium 2, 8, 18, 32, 25, 9, 2
97 Berkelium 2, 8, 18, 32, 27, 8, 2
98 Californium 2, 8, 18, 32, 28, 8, 2
99 Einsteinium 2, 8, 18, 32, 29, 8, 2
100 Fermium 2, 8, 18, 32, 30, 8, 2
101 Mendelevium 2, 8, 18, 32, 31, 8, 2
102 Nobelium 2, 8, 18, 32, 32, 8, 2
103 Lawrencium 2, 8, 18, 32, 32, 8, 3
104 Rutherfordium 2, 8, 18, 32, 32, 10, 2 4
105 Dubnium 2, 8, 18, 32, 32, 11, 2 5
106 Seaborgium 2, 8, 18, 32, 32, 12, 2 6
107 Bohrium 2, 8, 18, 32, 32, 13, 2 7
108 Hassium 2, 8, 18, 32, 32, 14, 2 8
109 Meitnerium 2, 8, 18, 32, 32, 15, 2 (?) 9
110 Darmstadtium 2, 8, 18, 32, 32, 16, 2 (?) 10
111 Roentgenium 2, 8, 18, 32, 32, 17, 2 (?) 11
112 Copernicium 2, 8, 18, 32, 32, 18, 2 (?) 12
113 Nihonium 2, 8, 18, 32, 32, 18, 3 (?) 13
114 Flerovium 2, 8, 18, 32, 32, 18, 4 (?) 14
115 Moscovium 2, 8, 18, 32, 32, 18, 5 (?) 15
116 Livermorium 2, 8, 18, 32, 32, 18, 6 (?) 16
117 Tennessine 2, 8, 18, 32, 32, 18, 7 (?) 17
118 Oganesson 2, 8, 18, 32, 32, 18, 8 (?) 18
See also
Wikimedia Commons has media related to Electron shell diagrams.
Periodic table (electron configurations)
Electron counting
18-Electron rule
Core charge
References
^ Jump up to: a b Re: Why do electron shells have set limits ? madsci.org, 17 March 1999, Dan Berger, Faculty Chemistry/Science, Bluffton College
^ Jump up to: a b Electron Subshells. Corrosion Source.
Jump up ^ Donald Sadoway, Introduction to Solid State Chemistry, Lecture 5
Jump up ^ Barkla, Charles G. (1911). "XXXIX.The spectra of the fluorescent Röntgen radiations". Philosophical Magazine. Series 6. 22 (129): 396. doi:10.1080/14786440908637137. Previously denoted by letters B and A (...). The letters K and L are, however, preferable, as it is highly probable that series of radiations both more absorbable and more penetrating exist.
Jump up ^ Jue, T. (2009). "Quantum Mechanic Basic to Biophysical Methods". Fundamental Concepts in Biophysics. Berlin: Springer. p. 33. ISBN 1-58829-973-2.
Jump up ^ The statement that the electrons in one subshell have exactly the same level of energy is true in an isolated atom, where it follows quantum-mechanically from the spherical symmetry of the system. When the atom is part of a molecule, this no longer holds; see, for example, crystal field theory.
Jump up ^ Orbitals. Chem4Kids. Retrieved on 1 December 2011.
Jump up ^ Electron & Shell Configuration. Chemistry.patent-invent.com. Retrieved on 1 December 2011.
Jump up ^ Chemical Reactions. Vision Learning (26 July 2011). Retrieved on 1 December 2011.
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Alek Skarlatos
From Wikipedia, the free encyclopedia
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Alek Skarlatos
Skarlatos in 2015
Born
Aleksander Reed Skarlatos
(1992-10-10) October 10, 1992 (age 26)
Castro Valley, California, U.S.
Nationality
American
Education
Umpqua Community College[1]
Home town
Roseburg, Oregon, U.S.
Television
Dancing with the Stars
Military career
Allegiance
United States
Service/branch
United States Army
Years of service
2012–2017
Rank
Specialist
Unit
Oregon Army National Guard
Battles/wars
War in Afghanistan
Awards
Knight of the Legion of Honour
United States Army Soldier's Medal
Aleksander Reed Skarlatos[2] (/skɑːrˈlɑːtoʊs/; born October 10, 1992) is an American actor and US Army National Guard soldier who, along with fellow Americans Spencer Stone and Anthony Sadler, a Briton and two Frenchmen,[3] stopped a gunman on a Paris-bound train travelling from Amsterdam via Brussels in August 2015. He has been awarded the United States Army Soldier's Medal from U.S. President Barack Obama,[4] and has received France's highest decoration, the Legion of Honour, from French president François Hollande as well as the medal of Arras, France.[3][5] Skarlatos competed on season 21 of ABC's Dancing with the Stars with pro dancer Lindsay Arnold, and finished in third place.[6]
Contents
1 Early life and career
2 2015 Thalys train attack
2.1 International recognition
3 Dancing with the Stars
4 Awards and decorations
5 Filmography
6 References
7 External links
Early life and career[edit]
Aleksander Reed Skarlatos was born in Castro Valley, California, to Emanuel Skarlatos, a Greek immigrant who arrived in the United States as a child,[7] and then-wife, Heidi Hansen. His step-parents are Karen Skarlatos and Tom Hansen respectively.[8][9] During his childhood, he grew up in Sacramento County, California, where he met Spencer Stone and Anthony Sadler while attending school in Fair Oaks, California, continuing their friendship into adulthood. All three men are described as sharing "a deeply religious background and a belief in service to their community" and are Christian.[10] Skarlatos graduated from Roseburg High School.
Skarlatos joined the Oregon Army National Guard in 2012 achieving the rank of Specialist. He completed a nine-month deployment in Afghanistan with the 186th Infantry Regiment, 41st Infantry Brigade Combat Team of the Oregon Army National Guard in 2015.[7][8][11][12] The acting adjutant general of Oregon has referred to Skarlatos as "a true citizen soldier who displayed the courage each of us would hope to find in ourselves."[13] Spc. Skarlatos had reenlisted for an additional two-years a month prior to the terrorist event on a French train in 2015 and left military service in November 2017.[14][15]
In October 2016, it was announced that Skarlatos, Spencer Stone and Anthony Sadler would make an appearance on Who Wants to Be a Millionaire as a part of the show's special "Hometown Heroes" week which would premiere on October 31, 2016.[16] He is currently running for Douglas County Commissioner in his home state of Oregon.
2015 Thalys train attack[edit]
Main article: 2015 Thalys train attack
On August 21, 2015, Skarlatos and two friends from his childhood home of Carmichael, California,[17] were traveling together during a vacation in Europe. He was recently back from Afghanistan, and had been traveling in Germany and the Netherlands and was to travel to Greece.[9] Skarlatos was sitting in a window seat[18] of Thalys train 9364 from Amsterdam bound to Paris via Brussels.[9] A 25-year-old Moroccan man, believed to be Ayoub El-Khazzani,[19] was in train car No. 12, armed with an AKM assault rifle and equipped with 270 rounds of ammunition.[20] Several people tried to stop the gunman, but failed to do so.[19] Skarlatos' friend, 23-year-old Spencer Stone, attacked the gunman first and was injured while trying to subdue him.[21] Skarlatos took action and seized the assailant's rifle,[22] beating him in the head with the muzzle of it until he was unconscious.[23]
International recognition[edit]
United States Defense Secretary Ash Carter awards the United States Army Soldier's Medal to Skarlatos (second from the left), an army specialist; the United States Air Force Airman's Medal to Spencer Stone (third from left), an airman first class; and the United States Department of Defense Medal for Valor to Anthony Sadler (fourth from left), at a ceremony in The Pentagon courtyard on September 17, 2015.
After the attack, on August 22, 2015, Skarlatos and his friends received international attention for their actions in thwarting the attack.[24] French president François Hollande awarded Skarlatos, his friends Spencer Stone and Anthony Sadler, as well as British businessman Chris Norman, France's highest decoration, Knights of the Legion of Honour (Chevaliers de la Légion d'honneur).[24] Hollande said the men "faced [off] with terror" and that they "gave us a lesson in courage, in will, and therefore in hope".[24] French Interior Minister Bernard Cazeneuve praised them for their bravery, as well as British Prime Minister David Cameron.[25]
The White House expressed gratitude for "courage and quick thinking of several passengers, including U.S. service members, who selflessly subdued the attacker..."[26] U.S. President Barack Obama telephoned the three Americans, thanking them for their heroic actions.[27] General Philip M. Breedlove of the U.S. European Command in Stuttgart, added his voice, calling the three Americans heroes for their actions which "clearly illustrate the courage and commitment our young men and women have all the time, whether they are on duty or on leave."[28]
Kevin Johnson, mayor of Sacramento, California, held a parade to honor Skarlatos, Sadler, Stone, and the victims of the September 11 attacks.[29] Megyn Kelly of Fox News Channel's The Kelly File, asked Skarlatos whether he had a different appreciation of what happened when the World Trade Center collapsed. "I feel so much more connected to terrorist attacks and things like that and victims of terrorist attacks," said Skarlatos, "That easily could have been us if any one of six or seven things went a different way."[30]
Dancing with the Stars[edit]
Skarlatos was announced as a competitor in season 21 of Dancing with the Stars. He was partnered with professional dancer Lindsay Arnold.[31] He said that he was inspired to participate on the show by Noah Galloway, a soldier who was on the previous season of the series.[32] Skarlatos and Arnold made it to the finals of the show and finished in third place.
Week #
Dance/Song
Judges' score
Result
Inaba Hough Tonioli
1 Foxtrot/"Ten Feet Tall" 8 7 7 No Elimination
2 Jazz/"Don't Stop Believin"
Quickstep/ "American Girl" 8
7 7
7 8
8 Safe
3 Tango/"Bad Things" 8 81/9 8 Safe
4 Paso Doble/"Wake Me Up" 8 8 8 Safe
52 Rumba/"Let It Go" 8 7/73 7 Safe
6 Jive/"Jailhouse Rock" 8 8/74 7 Safe
7 Viennese Waltz/"Haunted"
Team Freestyle/"Ghostbusters" 9
9 8
10 8
9 Safe
8 Contemporary/"Holding Out for a Hero"
Samba Dance-Off/"Lean On" 9
No 8
Given 8
Points Safe
9 Salsa/"Back It Up"
Team-Up Dance (Paso Doble)/"We Will Rock You" 8
8 8
8 8
8 Safe
10
Semi-finals Waltz/"America the Beautiful"
Cha-cha-cha Dance-off/"Fun"
Trio Argentine Tango/"Ex's & Oh's" 10
No
9 10
Given
9 10
Points
9 No Elimination
11
Finals Rumba/"The Pieces Don't Fit Anymore
Freestyle/"Marchin On"
Rumba & Tango Fusion/"A Sky Full of Stars" 9
10
9 9
10
9 9
10
9
Third place
1 Score given by guest judge Alfonso Ribeiro.
2 This week only, for "Partner Switch-Up" week, Skarlatos performed with Emma Slater instead of Arnold.
3 Score given by guest judge Maksim Chmerkovskiy.
4 Score given by guest judge Olivia Newton-John.
Awards and decorations[edit]
Air Assault Badge
Expert Marksmanship Badge with one weapon bar
41st Infantry Division Combat Service Identification Badge
186th Infantry Regiment Distinctive Unit Insignia
1 Service stripe
1 Overseas Service Bar
Soldier's Medal [33]
Army Achievement Medal
Army Meritorious Unit Commendation
Army Good Conduct Medal
National Defense Service Medal
Afghanistan Campaign Medal with two bronze service stars
Global War on Terrorism Service Medal
Armed Forces Reserve Medal with "M" device
Army Service Ribbon
Overseas Service Ribbon
NATO Medal for service with ISAF
Legion of Honour, Knight (France) [34]
Philippine Republic Presidential Unit Citation
Oregon Distinguished Service Medal[35]
Oregon Faithful Service Medal with "M" device
Received the bravery medal of the city of Arras, France.[34]
Received the EANGUS[36] Humanitarian Medal [37]
Received the NGAUS[38] Valley Forge Cross for Heroism[39][40]
Filmography[edit]
Year
Title
Role
Notes
2018 The 15:17 to Paris Himself Film based on Skarlatos' memoir of the same title; filming began July 11, 2017
References[edit]
Jump up ^ "Terror Train Hero Alek Skarlatos Oregon Shooting Hits Close to Home ... Bolts Out of 'DWTS' Rehearsal". TMZ. October 1, 2015. Retrieved October 2, 2015.
Jump up ^ "Guardsman to get Soldiers Medal for subduing gunman on train". National Guard Bureau. August 26, 2015. Retrieved September 6, 2015.
^ Jump up to: a b Miner, Collin (August 27, 2015). "Alek Skarlatos: 'Good to be home with family'". KOIN6. Retrieved September 3, 2015.
Jump up ^ "Obama lauds 'train heroes' at White House". Yahoo! News. AFP. Retrieved September 18, 2015.
Jump up ^ "Alek Skarlatos, 2 other Americans receive France's top honor for stopping armed attacker". The Associated Press. The Oregonian. August 24, 2015. Retrieved September 3, 2015.
Jump up ^ "Oregon's Train Hero Cast in ABC's New 'Dancing' Cast". Oregon Public Broadcasting. September 2, 2015. Retrieved September 3, 2015.
^ Jump up to: a b Carey, Stacy (September 6, 2015). "Who is Alek Skarlatos of 'Dancing with the Stars'?". inquisitr. Retrieved September 6, 2015.
^ Jump up to: a b Bailey Jr, Everton (August 21, 2015). "Oregon soldier calls from France to say 'he and his friend took down a terrorist,' dad says". The Oregonian. Retrieved September 3, 2015.
^ Jump up to: a b c "3 Americans praised for subduing gunman on European train". Associated Press. Newsday. August 22, 2015. Retrieved September 4, 2015.
Jump up ^ Sangree, Hudson. "Carmichael childhood, faith unite friends who stopped train attack". The Sacramento Bee. Retrieved June 6, 2016.
Jump up ^ Cameron Smith (2015). "Oregon has a community of veterans that continue to serve" (Veterans Day ed.). Oregon Department of Veterans' Affairs. p. 2. Retrieved April 18, 2018.
Jump up ^ Lindsay Adams-Spinner ARNG G1 STRATCOMM (October 12, 2015). "Guardsman honored for subduing gunman on train in France". g1arng.army.pentagon.mil. US Army National Guard. Archived from the original on October 2, 2016. Retrieved April 18, 2018.
Jump up ^ National Guard Bureau (August 26, 2015). "Guardsman to get Soldiers Medal for subduing gunman on train". www.army.mil. US Army. Retrieved April 18, 2018.
Jump up ^ Charlsy Panzino (February 4, 2018). "Heroes-turned-actors: 3 stars of 'The 15:17 to Paris' talk about their roles of a lifetime". armytimes.com. Sightline Media Group. Retrieved April 18, 2018.
Jump up ^ Katie Lange (February 8, 2018). "DoD Assets Set Scene for Heroes in '15:17 to Paris'". Defense Media Activity. www.dodlive.mil. Department of Defense. Retrieved April 18, 2018.
Jump up ^ Fletcher, Ed (October 28, 2016). "Millions await French train heroes". The Sacramento Bee. Retrieved October 30, 2016.
Jump up ^ "Carmichael childhood, faith unite friends who stopped train attack". sacbee. Retrieved October 31, 2015.
Jump up ^ "Alek Skarlatos' Terrorist Takedown: It Was Pure Instinct" (video). AssessHollywood. Retrieved September 11, 2015.
^ Jump up to: a b Barrett, David (August 23, 2015). "Revealed: The mystery man who tackled AK-47 assault rifle from train gunman". The Daily Telegraph. Retrieved September 4, 2015.
Jump up ^ Gray, Melissa; Meilhan, Pierre (August 22, 2015). "Americans who thwarted train attack praised for 'exceptional courage'". CNN. Retrieved September 4, 2015.
Jump up ^ Mikelbank, Peter (August 22, 2015). "'Wrong Place, Right People': U.S. Servicemen, Passengers Speak Out after Foiling Possible Terror Attack on European Train". People. Retrieved September 4, 2015.
Jump up ^ Baker, Keiligh; Baker, Darren (August 22, 2015). "Crew on Paris-bound train 'barricaded themselves in their staffroom and locked the door as Kalashnikov-wielding terrorist went on the rampage – leaving PASSENGERS to take him down'". Daily Mail. Retrieved September 4, 2015.
Jump up ^ NOSSITER, ADAM (August 22, 2015). "A Shot, a Glimpse of an AK-47, and U.S. Servicemen Pounced on Gunman on Train to France". The New York Times. Retrieved September 4, 2015.
^ Jump up to: a b c Chrisafis, Angelique; Kassam, Ashifa (August 24, 2015). "French train attack men given Légion d'honneur for 'preventing massacre'". theguardian. Paris. Retrieved September 4, 2015.
Jump up ^ "France train shooting: Hollande thanks 'heroes' who foiled gunman". BBC. August 22, 2015. Retrieved September 4, 2015.
Jump up ^ Ellis, Ralph; King, Jessica; Dailey, Peter; Seshadri, Archith (August 22, 2015). "2 members of U.S. military stop Islamist attacker on train in Belgium". CNN. Retrieved September 4, 2015.
Jump up ^ Karimi, Faith (August 23, 2015). "Train shooting heroes: The men who helped avert a massacre in Europe". CNN. Retrieved September 4, 2015.
Jump up ^ "Breedlove: U.S. Troops 'Heroes' in Train Attack". Stuttgart, Germany: United States Department of Defense (DoD). Retrieved September 4, 2015.
Jump up ^ Ortiz, Gamaliel (September 3, 2015). "Mayor releases details for parade honoring Sacramento heroes". KCRA. Retrieved September 5, 2015.
Jump up ^ "French train heroes discuss 9/11 during Sacramento parade in their honor". ABC7. Sacramento, California. September 12, 2015. Archived from the original on September 13, 2015. Retrieved September 13, 2015.
Jump up ^ "Dancing with the Stars Season 21 Cast Announcement". ABC. September 2, 2015. Retrieved September 5, 2015.
Jump up ^ Glines, Carole (September 11, 2015). "Terror train hero Alek Skarlatos was inspired to do 'DWTS' by last season's courageous star Noah Galloway". FOX News. Retrieved September 11, 2015.
Jump up ^ KATU News (staff) (August 25, 2015). "Oregon hero, Spc. Alek Skarlatos, to be awarded Soldiers Medal". kval.com. Eugene, Oregon: Sinclair Broadcast Group via KVAL 13. Retrieved April 18, 2018.
^ Jump up to: a b Meredith Worthen (February 8, 2018). "Meet the Real Heroes of '15:17 to Paris'". biography.com. Retrieved April 18, 2018.
Jump up ^ KATU News (staff) (February 17, 2016). "Governor presents Spc. Skarlatos with Oregon Distinguished Service Medal". katu.com. Portland, Oregon: Sinclair Broadcast Group via KATU 2. Retrieved April 18, 2018.
Jump up ^ "Individual Awards - The EANGUS Humanitarian Medal". eangus.org. Retrieved April 18, 2018.
Jump up ^ John Harris (April 30, 2016). "EANGUS Humanitarian award winner Alek Skarlatos". msncoa.org. Retrieved April 18, 2018.
Jump up ^ "United Voice for the National Guard". ngaus.org. Retrieved April 18, 2018.
Jump up ^ "Valley Forge Cross for Heroism". ngaus.org. Retrieved April 18, 2018.
Jump up ^ "Award Recipients (1998 - 2017)". ngaus.org. Retrieved April 18, 2018.
External links[edit]
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Alek Skarlatos on Dancing with the Stars
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