Usable quantity

Aquifer A permeable geologic unit with the ability to store, transmit, and yield fresh water in usable quantities. 

There is a tendency to reserve semisynthetic and totally synthetic methods for the introduction of bonds and residues that cannot be specified by the genetic code. The present chapter will concentrate on these aspects. However, semisynthesis can have a role to play even when building structures that are completely accessible to the genetic code. The first industrial challenge for the emerging technologies of total chemical synthesis, recombinant protein expression, and semisynthesis was the economic production of human insulin in pharmaceutically usable quantity and quality. The semisynthetic human insulin that was made from porcine insulin proved exceptionally convenient to produce, and was the first introduction to human insulin for very many patients. 

If the technique is to be used for the detection of antibodies in serum for example (which will be polyclonal by nature) a polyclonal antibody may be preferable in order to compete more effectively with the antibody in the serum. Batch to batch variation in polyclonal antibodies, does, however, make the establishment of the ELISA more difficult and each the assay must be optimized every time a new batch is prepared. Antibodies may be aliquoted and frozen at -20°C or lower in small, usable quantities. 

Trityldifluoroamine and isopropyl difluorocarbamate are reported to be stable reagents which permit the generation of difluoroamine directly with a minimum of preliminary effort. Tetrafluorohydrazine also can be converted to difluoroamine with ordinary laboratory equipment. If these difluoroamino compounds are not available or if expense is a factor to be considered, the straightforward fluorination of urea or sulfamide in water followed by hydrolysis in situ permits the preparation of usable quantities of difluoroamine in a simple manner. 

Bryan Palaszewski s summary described the fiendishly difficult challenges to making these otherworldly materials in usable quantities, but also some of the promises of atomic hydrogen Modern experiments use nanogram samples of atomic hydrogen, whereas up to many hundred tons may be required for each launch from Earth to orbit, he wrote. 

Given a wealth of natural chemical scaffolds for improved drug design, our ability to generate novel pharmaceuticals requires increased understanding of the biosynthetic processes that may lead to their discovery and production. Polyketide and nonribosomal peptide assembly offers enormous potential for development of combinatorial biosynthetic methods. The structural complexity of these natural products often prohibits practical chemical synthesis, which underscores the need for alternative means of accessing them in usable quantities. Research in this area requires in-depth knowledge of chemical,... 

Residue Remaining and usable quantity of an intermediate which may be used in the manufacture of a subsequent lot of product. 

In a semiconductor material, the forbidden-energy gap is such that electrons in usable quantities are able to jump across it from the filled valence band to the empty eonduction band.1 1 The three elements that form the covalent carbides, i.e., boron, silicon, and carbon (in the form of doped diamond) are semiconductors and one would expect to find semiconductor properties in their compounds. 

Groundwater is water located below the ground surface, in soil pore spaces, and in the fractures of rock formations. The water moves down into the ground because of gravity, passing between particles of soil, sand, gravel, or rock until it reaches a depth where the ground is filled, or saturated, with water. The area that is filled with water is called the saturated zone, and the top of this zone is called the water table. A porous or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. 

On the Stand (Legal Issues and Questions) In methamphetamine and similar cases in which diluted samples are encountered, the forensic chemist may be asked about "usable quantity." In some jurisdictions, the prosecution is required to prove not only that the defendant had a controlled substance, but that the amount possessed was usable. This concept is abo referred to as "measurable quantity." Since quantitation of the methamphetamine femily b not routinely performed, a concentration or percentage value of purity b not always available. The defense may argue that the amoimt present was so small as to be negligible or harmless. Because exhibits are received with low concaitrations of the controlled substance, this b a reasonable question. 

Theophylline Tropane alkaloid Tryptamines Usable quantity... 

What is the difference between aggregate weight and usable quantity ... 

The actinoid series encompasses the fourteen chemical elements with atomic numbers from 90 to 103, thorium (Th) to lawrencium (Lr). The actinoid series derives its name from the group-IIla element actinium (Ac) which can be included in the series for the purpose of comparison. Only Th and uranium (U) occur in usable quantities in nature. The other actinoids are man-made elements. Pure Th is a silvery-white metal which is air-stable and retains its luster for several months. U exhibits three crystallographic modifications as follows a (688°C) —> P (776°C) —> U is a heavy, silvery-white metal. The luster of freshly prepared americium (Am) is white and more silvery than neptunium (Np) or plutonium (Pu) prepared in the same manner. All actinoid elements are radioactive. Table 2.113 sutnmarizes some physical properties of actinoid metals (Th, U and Am). 

The polymerase chain reaction (PCR) is a means to amplify a given stretch of nucleotides to determine their relative concentration in different cell samples, or to produce usable quantities of a sequence of nucleotides for DNA cloning. The technique allows for the amplification of a few copies (in theory, only one copy is needed) of a specific piece of DNA into perhaps billions of copies in a relatively short time. The procedure is relatively inexpensive, requiring only a thermocycler and the appropriate enzymes and reagents for processing. The first description of PCR was published in 1985 (Saiki et al., 1985), and has proven to be such an important technique that the Nobel Prize in 1993 was awarded to Kary Banks MuUis for its discovery. 

Note an aquifer is defined as a geologic material that will 3deld groundwater in usable quantities. 

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