Corona (pronounced kuh-roh-nuh)
(1) A white or colored circle or set of
concentric circles of light seen around a luminous body.
(2) In meteorology, such a circle or set of
circles having a small radius and ranging in color from blue inside to red
outside, attributable to the diffraction caused by thin clouds, mist, or
sometimes dust (distinguished from halo).
(3) In solar astronomy, a faintly luminous
envelope outside of the sun's chromosphere, the inner part consisting of highly
ionized elements; also called aureola & aureole.
(4) A long, straight, un-tapered cigar, rounded
at the closed end.
(5) In botany, a crown-like appendage, especially
one on the inner side of a corolla, as in the narcissus.
(6) In anatomy, the upper portion or crown of a
part, as of the head.
(7) In architecture, the projecting, slab-like
member of a classical cornice supported by the bed molding or by modillions,
dentils, etc., and supporting the cymatium.
(8) The tonsure of a monk or other cleric.
(9) In ecclesiastical dress, a gold-colored
stripe around the lower edge of a clerical headdress, as of a miter.
(10) A chandelier of wrought metal, having the
form of one or more concentric hoops.
(11) In zoology, the head or upper surface of an
animal, such as the body of an echinoid or the disc and arms of a crinoid.
(12) As Coronaviruses, a group of viruses which
infect mammals and birds. In humans, they
cause usually mild (including 229E, the common cold) respiratory infections but
forms such as SARS, MERS the famous COVID-19 can be lethal.
1555–1565: From the Latin corōna (garland, crown) from the Ancient Greek κορώνη (korṓnē or korōnis
(crown, any curved object)), akin to
korōnís (wreath; curved, beaked) &
kórax (crow; raven); related was the Latin curvus (curved). A doublet
of crown, the plural forms are coronas & coronae.
COVID-19 and Coca-Cola
COVID-19 (an abbreviation of coronavirus disease 2019) was the name of the disease caused by SARS-CoV-2. The name was adopted in February 2020, chosen by the World Health Organization (WHO) in partnership with the Committee on Taxonomy of Viruses; until then, variously it had been called 2019-nCoV, Novel coronavirus or Wuhan coronavirus. SARS-CoV-2 is related to MERS-CoV (which causes Middle East respiratory syndrome (MERS)) and SARS-CoV (which causes severe acute respiratory syndrome (SARS)).
The Sun and its corona (left) and a depiction of the SARS-CoV-2 virus (bottom).
The class to which these viruses belong is called corona because, when viewed under an electron microscope, there’s a resemblance to the crown-like corona (the halo or ring of fire) around the Sun, seem when viewed through an appropriate telescope or other device. The corona around the sun has long been known but viruses have been seen only since the development of the electron microscope because human viruses are very small, typically 100 nanometers (1 metre = 1,000 mm = 1,000,000 micrometres = 1,000,000,000 nanometres). In the evolutionary timeline of life on earth, it's believed bacteria emerged quite some time before viruses. Bacteria appear to have been one of the earliest forms of life and, because no evidence of life has yet been detected anywhere else in the universe, they're perhaps among the oldest anywhere. Single-celled organisms with a relatively simple structure and capable of independent reproduction, bacteria are thought to have appeared some 3.5 to 3.8 billion years ago (the Earth dating back 4.5 billion) and the evidence suggests the viruses emerged 2-3 billions years ago. Unlike bacteria, viruses are not considered living organisms in the traditional sense because they cannot carry out metabolic processes or reproduce on their own; instead, they are genetic material (DNA or RNA) enclosed in a protein coat.
As far as is known, all life forms now extant (and all extinct forms known) are descended ultimately from the one initial instance; life started once which means humans are related to cats, dogs, trees & bananas as well as to bacteria & viruses. That makes people, bacteria and just about everything else vulnerable to infection by one virus or another, the consequences ranging from nothing to death but the behavior can also be used to advantage and a certain class of virus, the bacteriophage, after a long period of neglect during the antibiotic era, is attracting new interest.
Some viruses can be helpful: A depiction of bacteriophages phaging.
Not all viruses are bad like SARS-CoV-2. A bacteriophage, known almost always as a phage, is a virus which infects and replicates within bacteria. Phages are composites of proteins that surround a DNA or RNA genome and may encode any number of genes from a handful to many hundreds. Phages replicate within the bacterium following the injection of their genome into the target cytoplasm. Phages exist naturally in the environment and are among the most common and diverse entities on earth. Serious research began in several parts of Europe during the late nineteenth century and have been used for almost a century as anti-bacterial agents the former USSR and Central Europe. In the West, phage therapy (using specific viruses to fight difficult bacterial infections) has been of interest for some time, attention heightened as the problem of antibiotic-resistant bacteria (superbugs in the popular imagination) began to grow in severity (the US Centers for Disease Control and Prevention (CDC) attributes one death every 15 minutes in the US to superbugs). Since the discovery of penicillin, antibiotics have been used as a reliable cure for those suffering from once lethal bacterial infections but, over decades, a handful (compared with the trillions and trillions killed) of bacteria have proved resistant to antibiotics and as these survivors multiply, new infections emerge. Historically this had prompted the development of revised or new antibiotics but the biological arms race has reached the point where some infections caused by called antibiotic resistant bacteria cannot be treated and for many other serious infections, the number of potent “last resort” antibiotics is dwindling.
Hence the interest in phages, a type of “friendly virus” which can be weaponized to fight even the most virulent and persistent bacterial infections. Phages work as well as they do because viruses like the tiresome SARS-Cov-2 that makes humans sick, phages can infect only bacteria and are selective about which they target, a vital aspect of their role in medicine because human survival depends on the billions of bacteria in our bodies. These phages are far from rare, existing in the natural environment almost everywhere on the planet and scientists conducting research find dirty waterways or damp, aerated, warm, decaying soil (both areas where high bacterial growth might be expected) are good places to collect samples. The advantages phages offer are well known but there are also drawbacks and indeed some of the features of phages manifest as both. For example, the great specificity of phages helpful in that they can be administered safely with the knowledge that no other organisms will be harmed but this can be a practical disadvantage in clinical medicine when it’s not known exactly which bacteria need to be targeted, which is why broad-spectrum antibiotics proved so effective at scale. Being wholly natural, the shelf-life of phages is highly variable and there’s little experience in their administration beyond some communities in Eastern Europe where they’ve been part of medical practice for over a century. Additionally, bacteria can develop resistance even to phages and one practical impediment to deployment not well recognized until recent years is that compared to chemical molecules, phages are quite big and there are sites in the human body which will be inaccessible.
Electron micrograph of a Coronaviruses in colorized and in grey-scale.
The images captured from electron microscopes are always in black-and-white but are often artificially colored in the post-production process for better visualization and to assist with analysis. Because of the resolution limit of the optical microscope, even at the highest magnification, viruses couldn’t be seen because their size meant they lay beyond the spectrum of visible light, the range of resolution being limited by the wavelength of the visible light that illuminates the specimen. It was the resolution of the electron microscope, developed in the early 1930s, and able to offer an illumination with a wavelength much smaller than visible light which first made viruses visible. An electron has the properties both of a particle and a wave so an electron’s wavelength is determined by its energy (or speed). If an electron is accelerated to a speed of a million meters per second (circa 2.2 million mph (3.5 million km/h)) the physical wavelength is around one-tenth of a nanometer or about the size of an atom. This permits an electron microscope to probe the structure of atoms in a crystal and thus see viruses.
Lindsay Lohan taking a 330ml lunch.In February 2021, at a time when the official number
of people with COVID-19 was around 107 million, mathematicians calculated all
the COVID-19 causing SARS-COV-2 virus then circulating the planet easily
would fit in a single (330ml) Coca-Cola can.
Using a model based on the viral load per currently infected victim
(which varies during the duration of the infection), it was estimated there
were at the time around two-hundred quadrillion (200 million billion or 2x10¹⁷). SARS-CoV-2 virus
particles in the world. Using that
number, knowing the size of the virus, it was possible to calculate the total
volume and even after accounting for the distinctive projecting spike proteins meaning
the spherical particles will leave gaps when stacked together, the total is
still less than the internal volume of the 330 millilitre can.
Rare collector’s item: Lindsay Lohan MH Corona Extra tobacco card #480: US$5.00 on eBay. Unrelated to this card is the specification of the corona cigars, straight-shaped cigars with rounded tops (the end taken to the lips) and defined by length: a corona about 5½ inches (140 mm) long; a petit corona (or corona chica) about 5 inches (125 mm) long, a tres petit corona about 4½ inches (115 mm) long & a half corona about 3¾ (95 mm) inches long.
The Toyota (Corona) 1600GT
1958 Toyota Corona "Van".
It
was the Toyota Corona (1957-2001) which not only established the company in the vital US
market but lent respectability to the very idea of the “Japanese car”, that
term in the early 1960s not the by-word for quality and reliability it would in
subsequent decades become. Noting the
success of the small (by US standards) Volkswagen Beetle and other imports, the
company shipped a small number of Coronas to the US in the late 1950s but they
were unsuitable for the environment (as indeed were a number of the diminutive
European models which lacked the ruggedness of the VW) and interest was
minimal, the Corona withdrawn from sale in 1960 although unsold models lingered
on the lots for another year.
1966 "shovel-nose" Toyota Corona.
It was the third generation Corona, launched in September 1964 in an array of body styles, which was the Toyota passenger car to achieve international success, including in the US. It was a thoroughly conventional design (ie mechanically a scaled down US sedan) with a body which was modern, inoffensive and practical although some thought the reverse-slanted nose strange. It came to be nick-named the “shovel-nose” and proved ahead of its time, adopted in 1972 by Lancia for the Beta and in 1976 it appeared on Ford’s Escort RS2000 before variations of the shape eventually became the default for manufacturers seeking to eke out as much aerodynamic efficiency as possible.
The "shovel-nose" caught on: 1972 Lancia Beta (left) & 1976 Ford Escort RS2000 (right).
The
export range appeared in volume but the most desirable models were reserved for
the JDM (Japanese domestic market), a long-standing, industry-wide practice which has had the
effect of creating a minor export business for those who can satisfy the demand
in markets like Australia, New Zealand & North America for the
high-performance versions which have something of a cult-following. The 1967 1600GT (or GT-5 for those with the optional five-speed gearbox) coupé (for this JDM “halo” model the Corona badge wasn’t used)
was modest compared with some of the wild machinery which would appear in
subsequent decades but by the standards of its time, there was some genuine sophistication. The body was the standard two-door hardtop
but the centrepiece was a double overhead camshaft (DOHC) cylinder head atop
the 1600 cm3 four cylinder engine, the head designed by Yamaha which
had also developed the one used on the straight-six in the exotic Toyota 2000 GT
sports car made famous by the appearance of a custom built roadster version in
the James Bond film You Only Live Twice (1967).
1967 Toyota 2000GT roadster. Two 2000GT coupés were converted into roadsters for You Only Live Twice (one used for filming, the other a "back-up"), the work undertaken by Toyota’s special Toyopet Service Centre in Tsunashima. The wire wheels were exclusive to the roadsters (15×5 inch magnesium wheels were used on the coupés) and the pair were very much movie props, neither vehicle fitted with side windows or a soft-top. The "back-up car" is now on display in the Toyota Automobile Museum.
Known internally as the 9R, the 1600GT engine took a traditionally English approach to increasing power: twin carburetors, big valves and a high-compression ratio, the combination yielding a then impressive 110 horsepower at 6200rpm, the latter number something to note given the crankshaft was supported by only three main bearings. Still, being a Toyota engine, reliability was solid and no history of bottom-end failure emerged; whether the unusual firing order (1243) had anything to do with this seems not to be discussed anywhere. To cope with the new-found power, the Corona’s suspension was strengthened with re-calibrated springs and dampers along with two torque rods to locate the back axle. That improved things but the Japanese manufacturers, although matching the Europeans in power, still had some way to go in achieving their dynamics; the 1600 GT was no cut-price Alfa Romeo. It was though very well equipped, another lesson Toyota and other Japanese factories would (painfully) teach the West. Always a low volume model, production of 1600 GTs totalled 2222, the last built late in 1968.
1967 Toyota 1600GT. They were available also in red and white.
1974 Toyota Corona advertising.
The 1600GT's cult following notwithstanding, it really wasn't representative of the Coronas which went around the world and for decades provided owners and fleets with reliable, if uninspiring transport (very much the Camry of their time). That made them memorable for many who may have enjoyed the charms of British, French or Italian machinery but found the quirks, oil-leaks, fragility or apparently insoluble issues electrical issues (often described as "gremlins") made ownership tiresome. Toyota were aware of the advantage their approach (which put a premium on basic engineering and quality control over the finer points of handling and high-speed braking) and their advertising for the Corona in the 1970s said explicitly: "When your heart says Europe but your head says Japan". People increasingly followed their heads and by 1989 Toyota released the Lexus, proving they were as good at building a Mercedes-Benz as they were at building Toyotas. It took many attempts for Mercedes-Benz to become (almost) as good at building Toyotas.