Thursday, June 30, 2011

The term “chemical genitalia” in insect biology

The term “chemical genitalia” refers to natural chemical compounds (accessory proteins accompanying semen) that influence sperm persistence and egg fertilization in multiple mating events. Marlene Zuk describes how male insects use this strategy to kill the sperm of previous mates or to render females less receptive to future matings [1].  Those chemicals have been best studied in the fruit fly Drosophila. She also informs us that the phrase “chemical genitalia” was originally used by William G. Eberhard of the Smithsonian Tropical Research Institute and his colleague Carlos Cordero from the National Autonomous University of Mexico to name the seminal products. Eberhard works in Panama and Costa Rica on a wide variety of spiders and insects.

The activity of chemical genitalia can be considered as a special form of sperm competition—or, more precise, as a post- or inter-coital “cryptic chemical attack,” eliminating or reducing the female choice over paternity.

Keywords: entomology, behavioral ecology, biochemistry, selective reproduction, sexual selection, evolution, competition among males, chemical activity

[1] Marlene Zuk: Sperm and Eggs on Six Legs. Natural History June 2011, 119 (6), 28-35.

The terms “sperm competition” and “cryptic female choice” in insect biology

In a recent Natural History article, Marlene Zuk looks from a female perspective at the reproduction of insects [1]— an area of study that some see as overloaded with male-dominated thinking and terminology.  A good example is the term “sperm competition,” which goes back to Geoffrey A. Parker at the University of Liverpool [2,3]. This phrase denotes the effort toward successful fathering in multiple mating events.

Who decides about the success and who controls of what happens in reproduction? The inseminating male or the receiving female? Different insect species, as Zuk illustrates, exhibit a zoo of  genitalia including penises with spikes, scoops, hooks, knobs, kinks, coils—you name it—to enhance sexual interaction and sperm ejaculation. But it may be the female who finally controls paternity. The defining term is “cryptic female choice,” which was coined in 1983 by Randy Thornhill at the University of New Mexico [4,5].  This phrase refers to the postcopulatory ability of females to favor one male of her species over another: this ability includes the selection of sperms from various partners, stored in different parts of her reproduction tract, before fertilizing her eggs. For example, the female moth Utetheisa ornatrix—after mating many times—selects only the sperm of males with large spermatophores for fertilization [6].

Keywords: entomology, behavioral ecology, selective reproduction, sexual selection, evolution, competition among males, post-coital activity

References and more to explore
[1] Marlene Zuk: Sperm and Eggs on Six Legs. Natural History June 2011, 119 (6), 28-35.
[2] What is Sperm Competition? [].
[3] Stuart Wigby and Tracey Chapman: Sperm competition. Magazine R100 [].
[4] Randy Thornhill, research and publications:
[5] Elia T. Ben-Ari: Choosy Females. BioScience January 2000, 50 (1), 7-12. [].
[6] Female sperm choice of the moth Utetheisa ornatrix [].

Tuesday, June 28, 2011

Acronym in science and publication: PLoS for Public Library of Science

PLoS stands for Public Library of Science. PLoS is a nonprofit organization of scientists and physicians commited to making scientific and medical literature freely available online [1]:  Every publication with PLoS is an open access publication that can be downloaded, copied, and (re)distributed.

The flagship journals of PLoS are PLoS Biology and PLoS Medicine [2-4]: PLoS Biology was the first to be launched in October 2003, followed by PLoS Medicine in October 2004.  Further domain- and platform-specific journals have been added: PLoS Computational Biology, PLoS Genetics, PLoS Pathogens, PLoS Neglected Tropical Diseases and PLoS One.

The PLoS publishing group was founded by Pat O. Brown, Mike Eisen and H. E. Varmus [4,5]. 

[1] Public Library of Science:
[2] PLoS Biology:
[3] PLoS Medicine:
[4] Harold Varmus: The Art and Politics of Science. W. W. Norton & Comany, New York and London, 2009; pages 146 and 161 to 165.
[5] P. O. Brown, M. B. Eisen and H. E. Varmus: Why PLoS Became a Publisher. PLoS Biology October 2003, 1(10): e36. DOI:

Monday, June 27, 2011

How the AIDS virus became to be named human immunodeficiency virus (HIV)

Harold Varmus—Nobel Laureate in Medicine—describes in his book “The ART and POLITICS of SCIENCE” how the AIDS retrovirus got its name [1]. When the debate over the name of the AIDS virus was in full swing, Varmus was head of the Retrovirus Study Group of the International Committee on the Taxonomy of Viruses (ICVT) and was charged with resolving the debate. At that time, when much less was known about this virus, other naming options had been proposed:

Lympadenopathy virus (LAV). This name was given by Frenchman Luc Montagnier of the Pasteur Institute, following his observations with the electron microscope on cells from the swollen lymph glands of patients developing AIDS symptoms. However this term did not conform to the usual format that includes the species in which the virus was found and the resultant pathology.

Human T cell leukemia virus/III (HTLV-III). This name indicates species (human) and pathology (leukemia). But the AIDS virus did not appear to cause leukemia. The name-proposing scientist, Robert Gallo of the National Institute of Health (NIH), therefore, let the L stand for lymphotropic (a term meaning that the virus preferentially infected lymphoid cell, compare with L in LAV) to be in line with his previous discovery of HTLV viruses. Yet, the HTLV-AIDS similarity is too weak to justify name anology. As Varmus writes, their are significant differences with respect to genetic content, shape of the virus particle, disease spectrum, and even multiplication strategy.

HTLV-III/LAV. This designation was a compromise thought to satisfy both of the above mentioned proposals. But a slashed notation is often used to indicate a combination rather than an alternative, such that the term HTLV-III/LAV could be misinterpreted as a virus double pack.

Many more options were generated, typically by inserting some word(s) between human (H) and virus (V). Finally, in May 1986 agreement upon the name human immunodeficiency virus (HIV) was reached—a term and an acronym now globally recognized.

HIV belongs to Class VI in the Baltimore Classification system, the class of retroviruses relying on reverse transcription via a double-stranded DNA for replication.

[1] Harold Varmus: The Art and Politics of Science. W. W. Norton & Comany, New York and London, 2009; pages 128 to 130.

The Baltimore Classification System for viruses is named after David Baltimore, who proposed it

The Baltimore Classification System for viruses is named after its developer David Baltimore. David Baltimore (born 1938 in New York) is an American biologist, who won the Nobel Prize in Physiology and Medicine in 1975 together with co-recipients Renato Dulbecco and Howard Martin Temin for their discoveries concerning the interaction between tumor viruses and the genetic material of the cell [1].

The Baltimore classification accounts for the different mechanisms of viral genome replication. This system is schematically organized via the relationship between the viral genome and the messenger RNA  (mRNA), which is critical in the translation during expression of the viral genome [2-4]. The following presentation of the Baltimore classification is based on the system and virus examples given in Bruce Voyles' book (first six classes) [4] and on web-based resources [2,3]:
  • Class I viruses, double-stranded DNA genomes: the genome is double-stranded DNA, so  mRNA is synthesized in the normal fashion using negative-strand DNA as a template. Examples: adenovirus, hepatitis B virus, cauliflower mosaic virus.
  • Class II viruses, single-stranded DNA genones: the genome is single-stranded DNA. At the time this scheme was proposed, only positive-strand Class II viruses were known, but negative-stand viruses have since been found. They are now designated Class IIa and Class IIb, respectively. Examples: parvovirus, maize streak virus.
  • Class III viruses, double-stranded RNA genomes: the genome is double-stranded RNA, one strand of which is therefore equivalent to mRNA. These viruses have segmented genomes. Each genome is transcribed separately to produce monocistronic mRNAs. Examples: reovirus, rotavirus.
  • Class IV viruses, positive-strand RNA genomes: the genome is single-stranded RNA that can serve as mRNA directly, so these are positive-strand viruses. There are two subclasses (IVa and IVb) based on differences in mechanisms for expression and replication of the genome in these viruses. Examples: poliovirus, hepatitis A virus, coxsackievirus, tobacco mosaic virus.
  • Class V viruses, negative-strand RNA genomes: the genome is single-stranded RNA that cannot serve directly as mRNA, but is instead the template for the synthesis of viral mRNA. Since the genome is complementary to the viral mRNAs, these are negative-strand viruses. Class Va and Vb viruses are also distinguished by differences in the mechanism used in expression and replication of their genomes. Examples: rabies virus, mumps virus, measles virus, influenza A and B, Lassa virus.
  • Class VI viruses, retroviruses, also termed RNA-tumor viruses: the genome is positive-strand RNA but its expression and replication require synthesis of a double-stranded DNA molecule (reverse transcription). Example: human immunodeficiency virus (HIV).
  • Class VII viruses: double-stranded DNA with RNA intermediate: This group of viruses relies on reverse transcription, but unlike the Class VI retroviruses, the transcription occurs inside the virus particle on maturation. On infection of a new cell, the first event to occur is repair of gapped genome, followed by transcription. Example: hepadnaviruses.
References and suggested reading
[1] David Baltimore, 1975 Nobel Laureate in
[2] ViralZone: The Baltimore classification clusters viruses into families depending on their type of genome [].
[3] Virology Tutorial: Classification of Viruses [].
[4] Bruce A. Voyles: The Biology of Viruses. WCB/McGraw-Hill, Salem, MA, 1993; pages 29-32.

Saturday, June 25, 2011

Acronym in Virology and International Cooperation: ICTV for International Committee on the Taxonomy of Viruses

ICTV stands for International Committee on Taxonomy of Viruses. This organization takes on the task of developing, refining, and maintaining a universal virus taxonomy [1]. Many viruses are known by acronym such as ALV or RSV, which is easy to memorize and a good start to find more information by going to the ICTV database (ICTVdB). The ICTVdB Index of Viruses contains an alphabetically ordered  list (including Greek letters and number prefixes) of virus acronyms. For example, for RSV the species name Rous sarcoma virus is given in italics and clickable to find details such as serotypes, strains and isolates. The virus name Rous sarcoma virus is shown in black, indicating that this is the accepted name. Browsing through the name list, you'll find names in various colors, indicating the taxonomic status.

The ICTV websites also include pages describing virus nomenclature, classification and provide access to taxonomy proposals. As an additional introduction to the virosphere and virus taxonomy, I like the sections How are Viruses Named? and The Baltimore Classification as well as What is a Virus? in the book by Bruce Voyles on Virus Biology [2].

References and suggested reading
[1] Vincent Racaniello: How viruses are classified. August 7, 2009 [].
[2] Bruce A. Voyles: The Biology of Viruses. WCB/McGraw-Hill, Salem, MA, 1993; pages 27-32.

Thursday, June 23, 2011

The sobriquet Brownstein

 The sobriquet Brownstein refers to the two medical scientists Michael Stuart Brown (born 1941, USA) and Joseph Leonard Goldstein (born 1940, USA),  who are sharing the 1985 Nobel Prize in Physiology and Medicine, awarded for their discoveries concerning  the regulation of the cholesterol metabolism [1].

Another Nobel Laureate in Medicine, Harold Varmus presents the Brownstein Duo [my term] as one of those rare examples of two individuals, who are working closely together for over a decade without legal ties, yet collaborating productively and becoming famous together (Chapter 8: Partnership in Science in [2]). Varmus points out the very similar age and training of Goldstein and Brown and their shared passion for understanding cholesterol metabolism, blood lipids, and atherosclerosis. Although they differ in their personalities, accents (South Carolina and New York), social relationships and cultural interests, their scientific bond brought them success. The German word Stein means rock, often used as a metaphor for something difficult to break—like a jointly earned Nobel Prize.

References and further reading
[1] Harold Varmus: The Art and Politics of Science. W. W. Norton & Comany, New York and London, 2009; page 115.
[2] 1985 Nobel Laureates in Medicine: Michael S. Brown [] and Joseph L. Goldstein [].

Wednesday, June 22, 2011

Acronym in physics: BCS standing for three physicists, who theoretically explained superconductivity

BCS stands for the physicists John Bardeen, Leon Cooper and Robert Schrieffer, who jointly developed a theory of superconductivity, what earned them the Nobel Prize in Physics in 1972 [1]. Their theory was originally published in 1957, giving an explanation of superconductivity, a phenomenon now known to occur in some 26 metallic elements and many compounds and alloys at (relatively) low temperatures [2]. The element, in which superconductivity was discovered in 1911, is mercury [3]: Heike Kammerlingh Onnes at Leiden University in the Netherlands cooled a sample of mercury to around 4 K and noticed that the electrical resistivity of the metal dropped to zero [4,5].

The BCS model is based on the two assumptions that (1) the superconducting particles are fermions [particles with half-integer spins: 1/2, 3/2, 5/2 … units of angular momentum, electron has spin 1/2] and that (2) they attract each other [5]. The key insight is that an electron moving through an elastic crystal lattice creates a slight distortion of the lattice, which, if persisting long enough, can affect a following electron. Cooper showed that this effect results in a current of bound electrons—the Cooper pairs—in superconductors [2,5]. Cooper pairing is a quantum effect.

BCS biographical notes [6]:
John Bardeen: American physicist, * May 23, 1908 in Madison (Wisconsin), † January 30, 1991 in Boston (Mass.), earned the Nobel Prize of Physics twice: first with Brattain and Shockley in 1956 for work on the transistor, second as mentioned above.
More at
Leon N. Cooper: American physicist, * February 2, 1930 in New York.
More at
John Robert Schrieffer: American physicist, * May 31, 1931 in Oak Park (Illinois).
More at

References and more to explore
[1] Thomas Burgner (2007): What is BCS Theory? see page 2 (and following pages) in
[2] Oxford Dictionary of Physics. Fourth and revised edition. Oxford University Press, New York, 2003.
[3] Hg, see solid state sniplink at
[4] J. Stajic, R. Coontz and I. Osborne: Happy 100th, Superconductivity! Science April 8, 2011, 322 (6026), page 189. [].
[5] Adrian Cho: Superconductivity's Smorgasbord Of Insights: A Movable Feast. Science April 8, 2011, 322 (6026), pp. 190-192. [].
[6] Autorenkollektiv: Lexikon der Naturwissenschaftler. Spektrum Akademischer Verlag, Heidelberg•Berlin, 2000.

Monday, June 20, 2011

Acronym in virology: ALV for avian leukosis virus

In the biology of viruses, the acronym ALV stands for avian leukosis virus [1]. The ALVs are closely related to RSV, the progenitor of which is assumed to have been an ALV [2]. In a chapter with the title “How Proto-oncogenes Participate in Cancer,” Harold Varmus explains the role that ALV played in cancer research. ALV is a retrovirus without viral oncogenes. Yet, ALV infects chickens, which can lead to cancer. Varmus tells us that the graduate student Greg Payne showed that—by studying chicken lymphomas—ALV proviruses could be found in cellular DNA on either sides of a proto-oncogene and in either orientation: a good starting point to “zoom in” and—at supramolecular level— investigate how proviruses affect expression of adjacent proto-oncogenes.

In a review on avian oncogenic viruses,  Irit Davidson also connects avian tumor viruses and human tumor research [3]. He presents viral-induced tumors in poultry and discusses findings for avian oncogenic viruses including the retroviruses ALV, avian leucosis virus subgroup J (ALV-J),  reticuloendotheliosis virus (REV) and lymphoproliferative disease virus (LPDV) as well as a herpesvirus named Marek's diseases virus (MDV).
Is there any virus without an acronym?
References and further reading
[1] Acronym Finder:
[2] Harold Varmus: The Art and Politics of Science. W. W. Norton & Comany, New York and London, 2009; pages 93 to 95.
[3] Irit Davidson: The Knowledge that Human Tumor Virology can Gain from Studies on Avian Tumor Viruses. Advances in Tumor Virology 2009, 1, 9-19. [PDF file available at].

Saturday, June 18, 2011

Acronym in geology and climate science: PETM for Paleocene-Eocene Thermal Maximum

In earth science and climatology, PETM stands for Paleocene-Eocene Thermal Maximum. This is a transient climate perturbation, associated with a brief, but intense, interval of global warming at the end of the Paleocene (65-56 mya) and the beginning of the Eocene (56-34 mya) [1,2]. Dissociation of  oceanic methane hydrate has been hypothesized as a cause, but various other factors need to be considered [3].

The PETM as a global warming event is often compared with current global warming trends. Lee R. Kump illustrates that global temperature is rising much faster today (1 to 4 °C per 100 years) than it did during the PETM (0.025 °C per 100 years) [2]. He explains that, based on the fossil record, one can conclude that the speed of climate change has a much greater ecological impact than the extent of change, because adjusting to rapid climate change is very difficult for most biological species.     

References and further reading
[1] U. Röhl, T. Westerhold, T. J. Bralower and J. C. Zachos: On the duration of the Paleocene-Eocene thermal maximum (PETM). Geochemistry, Geophysics, Geosystems December 2007, 8 (2), 13 pages [].
[2] L. R. Kump: The Last Great Global Warming. Sci. Am. July 2011, 305 (1), 56-61 [].
[3] J. A. Higgins and D. P. Schrag: Beyond methane: Towards a theory for the Paleocene-Eocene Thermal Maximum. Earth and Planetary Science Letters 2006, 245, 523-537 [].

A short term in astronomy: H-R for Hertzsprung-Russell, naming the stellar luminosity/surface-temperature diagram

The H-R diagram, short for Hertzsprung-Russell diagram, is named after the Danish astronomer Ejnar Hertzsprung (1873-1967) and the American astronomer Henry Norris Russell (1877-1957) [1]. This diagram is celebrating its centennial this year. Ken Croswell provides the detailed naming history of  this diagram [2]:  
Ejnar Hertzspung sketched his first luminosoty-color diagram of star clusters in 1908. German astronomer Hans Rosenberg, who likely knew of Hertzsprung's work, published such a diagram in 1910, and Hertzsprung himself published several in 1911. At the time, he was an unknown. In contrast, Henry Norris Russell was one of America's foremost astronomers. In 1913, unaware of Hertzsprung's work, he plotted his own diagram. Because of Russell's prestige, astronomers first called the plot the Russell diagram, then the Russell-Hertzsprung diagram and finally—getting the historical order right—the Hertzsprung-Russell diagram.
What a plot!

The H-R diagrams is a plot of the visual luminosity versus the surface temperature of stars including supergiants, white and brown dwarfs and, of course, our sun [2.1, 3]. The main groups of clustered or roughly lined-up stars in the diagram represent supergiants, giants, main sequence stars and white dwarfs. The H-R diagram is a vital pattern recognition tool to explore similarities and differences between stars and to compare some of their properties. With the help of the H-R diagram, for example, you can check your understanding of the life cycle of a star [4].

[1] Autorenkollektiv: Lexikon der Naturwissenschaftler. Spektrum Akademischer Verlag, Heidelberg•Berlin, 2000.
[2] Ken Croswell: The Periodic Table of the Cosmos. Sci. Am. July 2011, 305 (1), 44-49. DOI:
[2.1] A User's Guide to the H-R Diagram:
[3] Hertzsprung-Russel Diagram:
[4] Hertzsprung-Russel Diagram:

Wednesday, June 15, 2011

Acronym in virology: RSV denoting different viruses

In the biology of viruses, the acronym RSV may stand for Rous sarcoma virus, respiratory syncytical virus, rice stripe virus and  ragged stunt virus [1,2]. To distinguish the latter two viruses, which can infect rice plants, the ragged stunt virus is often referred to as rice ragged stunt virus with acronym RRSV [2]. The respiratory syncytial virus can infect humans, causing mild, cold-like symptoms in adults and older children, but may cause more serious problems in babies [3]. 

The Rous sarcoma virus is a chicken virus, belonging to the oncovirinae subfamily of retroviruses [4]. It was the first tumor virus to be described in the literature, discovered by Peyton Rous at the Rockefeller Institute in New York in 1911. The virus is now bearing his name. For his discovery of this tumorinducing virus, Peyton Rous was awarded the Nobel Prize in Physiology and Medicine in 1966 (actually half the prize, Charles Brenton Huggins received the other half for his discovery concerning hormonal treatment of prostatic cancer) [5].

The Nobel Prize-winning cancer researcher Harold Varmus provides a brief history of the discovery of the Rous sarcoma virus and illuminates its significance in the context of later research and discoveries, including viral cancer genes, proto-oncogenes and multiplication strategies for retroviruses such as HIV [6]. Varmus notes, that Peyton Rous, ironically, became an opponent, rather than a proponent, of the genetic origins of cancer that his virus ultimately helped to reveal.    

References and further reading
[1] Acronym Finder:
[2] Research Team for Vector-Borne Diseases: Molecular detection of nine rice viruses by a reverse-transcription loop-mediated isothermal amplification assay. J. Virol. Methods Dec. 2010, 170 (1-2), 90-93.[].
[3] MedlinePlus: Respiratory Syncytical Virus Infection [].
[4] Bruce A. Voyles: The Biology of Viruses. WCB/McGraw-Hill, Salem, MA, 1993; page 280.
[5] Nobel Prize in Physiology or Medine Winners 2010-1901:
[6] Harold Varmus: The Art and Politics of Science. W. W. Norton & Comany, New York and London, 2009; pages 53 to 55.

Monday, June 13, 2011

A non-inviting name for an exciting place: Sperrgebiet National Park

 The masculine noun Sperrgebiet is a compositum derived from the German words sperren and Gebiet. The verb sperren means to close or to cordon off and the noun Gebiet means area or district.  Thus, Sperrgebiet means prohibited area or forbidden area—forbidden for unauthorized persons. Such a word does not sound inviting, but in Namibia a National Park got this term in its name for historical reasons. In 1908, when present-day Namibia was South-West Africa, a German protectorate (colony), diamonds were found in its southwest corner, which was then declared Sperrgebiet and made accessible only to a diamond company and its miners [1].

Namibia, one of the world's first nations to write environmental protection into its constitution, set its entire Atlantic coast aside as a string of National Parks with the exception of a few towns and mining areas. Between Angola in the north and South Africa you'll find Iona National Park, Skeleton Coast Park (another non-inviting name!), Dorob National Park, Namib-Naukluft Park, Namibian Islands' Marine Protected Area and—last not least—Sperrgebiet National Park (see map on page 69 in [1]).

A Ministry of Environment and Tourism (MET) concessionaire is needed to travel into Sperrgebiet National Park. Don't be surprised if you find other German names there such as Bogenfels, meaning arch-rock, for a colossal 55m tall rock arch  (different languages, different word order) at the southern extremity of the park [2]. You shouldn't have problems with the translation of Diamantenmine to diamond mine. But what you are supposed to do, if you find a diamond, I don't know.

References and interesting links
[1] Alexandra Fuller: Africa's Super Park. National Geographic June 2011, 219 (6), 60-77. [].
[2] The Sperrbebiet National Park:

Sunday, June 12, 2011

Göbekli Tepe means Potbelly Hill

Tepe means hill, mound or knoll in Turkish. In southeastern Turkey, north of the border of Syria and north (or within) the Fertile Crescent of the Neolithic, we find place names such as Ziyaret Tepe, Kenan Tepe and Göbekli Tepe on today's archaeological maps [1-5]. All these tepes and the surrounding areas are digging sites. Göbekli Tepe is located nine miles to the east of the Turkish town of  Şanlıurfa, (also known by the shorter name Urfa). Göbekli Tepe means Potbelly Hill. Local people gave this name to the site, which is part of a ridge and has the shape of a  rounded crest [5].

Being much older than Stonehenge, Göbekli Tepe has made a lot of headlines over recent years as the first temple and spiritual meeting place (sometimes with a question mark [4]). Among the mysteries and fascinating artworks of this neolithic architecture are the relief animals carved in its stone pillars. There also is a fierce-looking creature erupting from a limestone wall, similar to sculptures we find at gothic church buildings.

The archaeologist Klaus Schmidt of the German Archaeological Institue (DAI), who is researching this site for over ten years together with European and Turkish scientists, gives us hints that excavation results can be interpreted in various ways. Was this a spiritual locus or a Neolithic Tivoli Garden? Further, this place has a Trojan dimensions, at least in the vertical direction: Schmidt is not certain if the bottom layer has been uncovered yet. Göbekli Tepe may change our understanding of the history of civilization. Schmidt makes an interesting point that the common belief (twenty years ago) was, that civilization was driven by ecological forces, but that we are now learning that civilization is a product of the human mind [5]. Whatever the driving forces behind this site, we at least can agree in the spirit of Louis Armstrong and Fats Domino: I found my thrill on Potbelly Hill!

Keywords: geography, history, archeology, nomadic people, hunter-gatherers 

[1] Ziyaret Tepe:
[2] L. S. Dodd, J. Schnereger, M. Abraham and B. J. Parker: Analysis of Metallurgical Finds at Kenan Tepe, Turkey. 2001 []. Note: this paper contains illustrative pictures of sites and findings.
[3] Sandra Scham: The World's First Temple. Archaeology Nov./Dec. 2008, 61 (6) [].
[4]  Andrew Curry: Gobekli Tepe: The World's First Temple? Smithsonian, November 2008 [].
[5] Charkes C. Mann: The Birth of Religion. National Geographic June 2011, 219 (6), 34-59. [].

Friday, June 10, 2011

Acronym in materials science: TSA for thaumasite sulfate attack

Thaumasite (for chemical composition see a short-hand cement chemistry-notation) is a naturally occurring mineral. However, its formation and transformation is of interest in the construction and repair of concrete-based structures including buildings, roads, bridges and tunnels. In a sulfate- and carbonate-rich environment, thaumasite sulfate attack (TSA) causes phase changes in construction materials. Its function in the destruction of concrete bodies is a subject of ongoing research: Milan Drábik argues in a recent article of materials chemistry, that the TSA role should not be overestimated[1]: the quantification of the TSA portion of overall deterioration caused by thaumasite/sulfate interaction remains the subject of discussion and further investigations. 

Keywords: materials science, technology, engineering, safety of buildings, damage, corrosion, chemical decomposition

[1] Milan Drábik: Thaumasite: Its Relevance to Sulphate Corrosion in Concrete. Nachrichten aus der Chemie May 2011, 59, VIII-X.
DOI: 10.1002/nadc.201180415.

A short-hand cement chemistry notation: CS · Cs · Cc · H15 for thaumasite

CS · Cs · Cc · H15 is a widely used short-hand notation for the mineral thaumasite [1]. In this notation, symbols CS, Cs, Cc and H15 represent the four components calcium silicate, calcium sulfate, calcium carbonate and hydrate (water), respectively, as they occur in the formula of thaumasite's chemical composition:  CaSiO3 · CaSO3 · CaCO3 · 15H2O. Another common formula presentation is [Ca3Si(OH)6·12H2O)](SO4)(CO3). Information snippets regarding thaumasite and various references can be found at Materials Matter! : Ca3Si(OH)6(CO3)(SO4)(H2O)12.

This special notation is for use within its domain of interest: chemistry and technology of building materials and composites. Notice that the symbols C, H, S and Cs conflict with their use to represent the chemical elements carbon, hydrogen, sulfur and cesium (caesium): non-supervised parsing software may run into problems encountering this string.

Thaumasite is a naturally occurring mineral, but most of the research and public interest derives from its role (along with ettringite) as a deterioration product of concrete and mortar in a sulfate- and carbonate-rich environment.

Keywords: materials science, mineralogy, engineering, safety of buildings, damage, nomenclature, material formula

[1] Milan Drábik: Thaumasite: Its Relevance to Sulphate Corrosion in Concrete. Nachrichten aus der Chemie May 2011, 59, VIII-X.
DOI: 10.1002/nadc.201180415.

Thursday, June 9, 2011

DMSP for dimethylsulfoniopropionate (cont'd) and 35S-DMSP for 35S-labeled dimethylsufoniopropionate

The acronym and molecular structure of the zwitterionic compound dimethylsulfoniopropionate (also spelled dimethylsulphoniopropionate) has been presented recently. In continuation of that post, I like to point to interesting links for DMSP at Materials Matter!: C5H10O2S. Further, there is a link (more being expected) for the 35S-labeled compound, abbreviated as 35S-DMSP: C5H10O2^35S.

Sunday, June 5, 2011

Acronym in chemistry and materials science: BSA for bis(trimethylsilyl)acetamide

In chemistry, BSA is short for bis(trimethylsilyl)acetamide. Structurally more precise is N,O-bis(trimethylsilyl)acetamide and more systematic, with regard to nomenclature rules, are the longer names N-trimethylsilyl-1-trimethylsilyloxyethanimine and trimethylsilyl N-(trimethylsilyl)ethanecarboximidate. (CH3)3SiOC(CH3)=NSi(CH3)3 is a structural formula for BSA, from which the empirical formula C8H21NOSi2 (molar mass: 203.43 g/mol) is derived. Further identifiers: CAS number 10416-59-8, ChemSpider ID 4523073 [trimethylsilyl (1E)-N-(trimethylsilyl)ethanimidioate], and Gelest Product Code SIB1846.0 [1].

BSA melts (freezes) at -24 °C. Its flash point is 42 °C and it can be distilled around 72°C under reduced pressure at 35 mm [1]. BSA has been applied, for example, to the derivatization (silylation) of alcohols, phenols, aldehydes and ketones and the formation of peptide bonds: find examples at  Materials Matter! using matform C8H21NOSi2 or bookmark, share and link BSA properties and applications of your interest.

[1] Barry Arkles (Editor): Silicon, Germanium, Tin and Lead Compounds, Metal Alkoxides, Diketonates and Carboxylates - A Survey of Properties and Chemistry. 2nd edition, Gelest, Inc., 1998; SIB1846.0 on page 125.

Saturday, June 4, 2011

Acronym in chemistry and materials science: HMDS for hexamethyldisilazane

In chemistry, HMDS is short for hexamethyldisilazane or, structurally more precise, 1,1,1,3,3,3-hexamethyldisilazane. The acronym HMDZ has also been used to denote this reagent. The IUPAC name is bis(trimethylsilyl)amine for this compound with molecular structure (CH3)3SiNHSi(CH3)3 and empirical formula C6H19NSi2 (molar mass: 161.39 g/mol). Further identifiers: CAS number 999-97-3, EC number 213-668-5, RTECS number JM9230000 and Gelest Product Code SIH6110.0 [1].

HMDS is a colorless liquid. Its flash point is 12 °C, its boiling point 126-7°C and its vapor pressure at 50°C is 50 mm [1]. HMDS is a versatile silylation reagent. Further properties and applications of HMDS can be found, for example, via Materials Matter! using matform C6H19NSi2.

[1] Barry Arkles (Editor): Silicon, Germanium, Tin and Lead Compounds, Metal Alkoxides, Diketonates and Carboxylates - A Survey of Properties and Chemistry. 2nd edition, Gelest, Inc., 1998; SIH6110.0 on page 177.