The mechanism of action of these drugs has not been completely worked out, but certain of them appear to act by reducing the oxidised form of iodine before it can iodinate thyroglobulin ( Astwood, 1954 ).

The exact mechanism of carbamazepine, gabapentin and pregabalin is similarly unclear, but these anticonvulsants are used to treat neuropathic pain with differing degrees of success.

Discovered in 1946 by Joshua Lederberg and Edward Tatum, conjugation is a mechanism of horizontal gene transfer as are transformation and transduction although these two other mechanisms do not involve cell-to-cell contact.

It is located outside the cell membrane and provides these cells with structural support and protection, in addition to acting as a filtering mechanism.

Motor-driven mechanical calculators had these between the drive motor and gear train, to limit damage when the mechanism jammed, as motors used in such calculators had high stall torque and were capable of causing damage to the mechanism if torque wasn't limited.

The lack of compaction of these regions is called bookmarking, which is an epigenetic mechanism believed to be important for transmitting to daughter cells the " memory " of which genes were active prior to entry into mitosis.

All these proteins share a catalytic mechanism of di-metal-ion-mediated nucleotide transfer, whereby two acidic residues located at the end of the first strand and between the second and third strands of the RRM-like unit respectively, chelate two divalent cations.

Between these is a " transduction mechanism " in which hormone binding induces allosteric modification that, in turn, produces the appropriate response.

There must be some unknown mechanism acting on these variables to give rise to the observed effects of " non-commuting quantum observables ", i. e. the Heisenberg uncertainty principle.

One speculated mechanism for some forms of inherited epilepsy are mutations of the genes that code for sodium channel proteins ; these defective sodium channels stay open for too long, thus making the neuron hyper-excitable.

Despite these differences, all known naturally-occurring codes are very similar to each other, and the coding mechanism is the same for all organisms: three-base codons, tRNA, ribosomes, reading the code in the same direction and translating the code three letters at a time into sequences of amino acids.

The mechanism for producing these jets is still not well understood.

The hypothetical right-handed neutrinos are not contained in any of these representations, which can explain their relative heaviness ( see seesaw mechanism ).

The principal of these is with the United States ( National Security Agency ), Canada ( Communications Security Establishment ), Australia ( Defence Signals Directorate ) and New Zealand ( Government Communications Security Bureau ), through the mechanism of the UK-US Security Agreement, a broad intelligence sharing agreement encompassing a range of intelligence collection methods.

Most geologists today accept that a combination of these phenomena can be used to explain granite intrusions, and that not all granites can be explained entirely by one or another mechanism.

In the 18th century, a link mechanism was developed connecting these hooks with pedals, leading to the invention of the single-action pedal harp.

This mechanism avoids requiring clients to download every message in the mailbox in order to perform these searches.

Herman Kuhn, quoting from Tattvarthasutra, describes karmas as " a mechanism that makes us thoroughly experience the themes of our life until we gained optimal knowledge from them and until our emotional attachment to these themes falls off.

All of these manners of articulation are pronounced with an airstream mechanism called pulmonic egressive, meaning that the air flows outward, and is powered by the lungs ( actually the ribs and diaphragm ).

There are several hypotheses about how tolerance develops, including opioid receptor phosphorylation ( which would change the receptor conformation ), functional decoupling of receptors from G-proteins ( leading to receptor desensitization ), μ-opioid receptor internalization and / or receptor down-regulation ( reducing the number of available receptors for morphine to act on ), and upregulation of the cAMP pathway ( a counterregulatory mechanism to opioid effects ) ( For a review of these processes, see Koch and Hollt.

At present, it is not clear if all of these represent distinct reactions or merely alternative outcomes of a common mechanism.

However, considering the mechanism of such ADRs, and in clinical practice, these formulations have not demonstrated a reduced risk of GI ulceration.

The mechanism of these renal ADRs is due to changes in renal haemodynamics ( blood flow ), ordinarily mediated by prostaglandins, which are affected by NSAIDs.

Also, it can be readily seen that the cutting and peeling types of failure show a steady state response, while the cracking mechanism is of a dynamic nature.

The simplest types of ball point pens have a cap to cover the tip when the pen is not in use, while others have a mechanism for retracting the tip.

Dichloroacetate ( DCA ) has been found to shrink tumors in vivo in rats, and has a plausible scientific mechanism: DCA appears to reactivate suppressed mitochondria in some types of oxygen-starved tumor cells, and thus promotes apoptosis.

Different types of heterotrimeric G proteins share a common mechanism.

These machines are mechanically similar since all three types use a handle connected to a flywheel by rope, chain, or strap to provide resistance to the user – the types differ only in braking mechanism.

Some astronomers believe the two types of star clusters form via the same basic mechanism, with the difference being that the conditions that allowed the formation of the very rich globular clusters containing hundreds of thousands of stars no longer prevail in the Milky Way.

In most types, the linear movement of the piston is converted to a rotating movement via a connecting rod and a crankshaft or by a swashplate or other suitable mechanism.

Initially, two major types of fission bombs were built: a relatively simple device that uses uranium-235 and a more complicated mechanism that uses plutonium-239 derived from uranium-238.

There are large differences between different types of flagellum ; the prokaryotic and eukaryotic flagella differ greatly in protein composition, structure, and mechanism of propulsion, however both are used for swimming.

Below is a list of five different types of bombs based on the fundamental explosive mechanism they employ.

The trapping and digestion mechanism usually employs two types of glands: stalked glands that secrete sweet mucilage to attract and ensnare insects and enzymes to digest them, and sessile glands that absorb the resulting nutrient soup ( the latter glands are missing in some species, such as D. erythrorhiza ).

This mechanism is popular in the UK, but the damage caused is common to most types of switches.

There are two basic types of watermill, one powered by a vertical waterwheel via a gearing mechanism, and the other equipped with a horizontal waterwheel without such a mechanism.

Certain types of very small artificial vesicle will automatically make themselves slightly asymmetric, although the mechanism by which this asymmetry is generated is very different from that in cells.

Coming full circle, investigation of these types of luminous supernovae suggests that some of them are due to explosions of extremely massive low metallicity stars by the pair instability mechanism, although not with the energies that were speculated for them decades earlier.

Both types of consumption tax create an incentive by end consumers to avoid or evade the tax, but the sales tax offers the buyer a mechanism to avoid or evade the tax — persuade the seller that the buyer is not really an end consumer, and therefore the seller is not legally required to collect it.

Similar structures can also form in lava tubes, associated with some types of lavacicles, although the mechanism of formation is very different.

The underlying cause may be a dysfunctional molecular mechanism in the primary cilia structures of the cell, organelles which are present in many cellular types throughout the human body.

In Chicago, the telephones were restricted to police use, but the boxes also contained a dial mechanism which members of the public could use to signal different types of alarms: there were eleven signals, including " Police Wagon Required ", " Thieves ", " Forgers ", " Murder ", " Accident ", " Fire " and " Drunkard ".

Conversion is commonly made via a few simple types of mechanism including:

Strangling can be divided into three general types according to the mechanism used:

These instruments exist in two main types: Standard prima instruments and concert instruments which differ from the Prima instruments in that they have a retuning mechanism placed in the side of the instrument.