In Philip Pullman's "His Dark Materials" trilogy of novels, Dust is a mysterious cosmic particle that is integral to the plot.
 In "Northern Lights", Lord Asriel reveals the origins of the term "Dust" to be from a passage from the slightly alternate version of the Bible in Lyra's world: "In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return" ( ).
QDPR (quinoid dihydropteridine reductase) is a human gene that produces the enzyme quinoid dihydropteridine reductase.
 This enzyme is part of the pathway that recycles a substance called tetrahydrobiopterin, also known as BH4.
 Tetrahydrobiopterin works with an enzyme called phenylalanine hydroxylase to process a substance called phenylalanine.
 Phenylalanine is an amino acid (a building block of proteins) that is obtained through the diet; it is found in all proteins and in some artificial sweeteners.
 When tetrahydrobiopterin interacts with phenylalanine hydroxylase, tetrahydrobiopterin is altered and must be recycled to a usable form.
 The regeneration of this substance is critical for the proper processing of several other amino acids in the body.
 Tetrahydrobiopterin also helps produce certain chemicals in the brain called neurotransmitters, which transmit signals between nerve cells.
His Dark Materials is an epic trilogy of fantasy novels by Philip Pullman consisting of "Northern Lights" (1995, published as "The Golden Compass" in North America), "The Subtle Knife" (1997), and "The Amber Spyglass" (2000).
 It follows the coming of age of two children, Lyra Belacqua and Will Parry, as they wander through a series of parallel universes.
 The three novels have won a number of awards, most notably the 2001 Whitbread Book of the Year prize, won by "The Amber Spyglass".
 "Northern Lights" won the Carnegie Medal for children's fiction in the UK in 1995.
 The trilogy took third place in the BBC's Big Read poll in 2003.
Alkaptonuria (black urine disease, black bone disease, or alcaptonuria) is a rare inherited genetic disorder in which the body cannot process the amino acids phenylalanine and tyrosine, which occur in protein.
 It is caused by a mutation in the "HGD" gene for the enzyme homogentisate 1,2-dioxygenase (EC 1.13.11.5 ); if a person inherits abnormal copies from each parent (it is a recessive condition) the body accumulates an intermediate substance called homogentisic acid in the blood and tissues.
 Homogentisic acid and its oxidized form "alkapton" are excreted in the urine, giving it an unusually dark color.
 The accumulating homogentisic acid causes damage to cartilage (ochronosis, leading to osteoarthritis) and heart valves as well as precipitating as kidney stones and stones in other organs.
 Symptoms usually develop in people over thirty years old, although the dark discoloration of the urine is present from birth.
Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen or asphalt.
 It is of higher quality than lignite coal but of poorer quality than anthracite.
 Formation is usually the result of high pressure being exerted on lignite.
 Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams.
 These distinctive sequences, which are classified according to either "dull, bright-banded" or "bright, dull-banded", is how bituminous coals are stratigraphically identified.
The Book of Dust is a forthcoming trilogy of fantasy novels by Philip Pullman.
 It is a companion trilogy to the "His Dark Materials" trilogy.
 The first book is set 10 years before "Northern Lights" and centres on Lyra Belacqua, one of the protagonists of the original trilogy.
 Alethiometers, dæmons and the Magisterium also return, alongside new characters, including a new hero.
William Parry is one of the protagonists in Philip Pullman's trilogy "His Dark Materials", along with Lyra Belacqua.
 He first appears in the series at the start of the second novel, "The Subtle Knife", and continues through to the final book, "The Amber Spyglass".
 Introduced as a 12-year-old boy, he meets and befriends Lyra in the world of Cittàgazze and teams up with her in order to uncover the mysteries of Dust and the disappearance of his own father many years previously.
 He later takes possession of the Subtle Knife which he uses to aid Lord Asriel in his bid to destroy the Authority.
The Subtle Knife, the second book in the "His Dark Materials" series, is a young-adult fantasy novel written by Philip Pullman and published in 1997.
 The novel continues the adventures of Lyra Belacqua as she investigates the mysterious Dust phenomenon and searches for her father.
 Will Parry is introduced as a companion to Lyra, and together they explore the new realms to which they have both been introduced.
Northern Lights (known as The Golden Compass in North America and some other countries) is a young-adult fantasy novel by Philip Pullman, published by Scholastic UK in 1995.
 Set in a parallel universe, it features the journey of Lyra Belacqua to the Arctic in search of her missing friend, Roger Parslow, and her imprisoned uncle, Lord Asriel, who has been conducting experiments with a mysterious substance known as "Dust".
Solubility is the property of a solid, liquid, or gaseous chemical substance called "solute" to dissolve in a solid, liquid, or gaseous solvent.
 The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and the pH of the solution.
 The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.
 The solubility of a substance is an entirely different property from the rate of solution, which is how fast it dissolves.

Question: "His Dark Materials" is an epic trilogy that includes this book, featuring experiments with a substance called "Dust."
Answer: Northern Lights