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'''Dihydro-orotate dehydrogenase''' is an electron transfer complex of the inner mitochondrial membrane, converting dihydro-orotate (Dho) into orotate, and linking electron transfer through the [[Q-junction]] to pyrimidine synthesis and thus to the control of biogenesis. +
'''Dihydroethidium''' (also called hydroethidine) is a cell permeant fluorescent probe used to analyse superoxide presence. It is a reduced form of ethidium that presents blue fluorescence, and after oxidation by superoxide becomes able to intercalate DNA and emits red fluorescence (excitation wavelength ~518–535 nm, emission ~605–610 nm). It has been used to detect superoxide by HPLC and by fluorescence microscopy. +
Dilution of the concentration of a compound or sample in the experimental chamber by a titration of another solution into the chamber. +
'''Dimensions''' are defined in the SI {''Quote''}: Physical quantities can be organized in a system of dimensions, where the system used is decided by convention. Each of the seven base quantities used in the SI is regarded as having its own dimension. .. All other quantities, with the exception of [[count]]s, are derived quantities, which may be written in terms of base quantities according to the equations of physics. The dimensions of the derived quantities are written as products of powers of the dimensions of the base quantities using the equations that relate the derived quantities to the base quantities.
There are quantities ''Q'' for which the defining equation is such that all of the dimensional exponents in the equation for the dimension of ''Q'' are zero. This is true in particular for any quantity that is defined as the ratio of two quantities of the same kind. .. There are also some quantities that cannot be described in terms of the seven base quantities of the SI, but have the nature of a [[count]]. Examples are a number of molecules, a number of cellular or biomolecular entities (for example copies of a particular nucleic acid sequence), or degeneracy in quantum mechanics. Counting quantities are also quantities with the associated unit one. {''end of Quote'': p 136, [[Bureau International des Poids et Mesures 2019 The International System of Units (SI)]]} +
'''Dimethyl sulfoxide''' is a polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water. DMSO may also be used as a cryoprotectant, added to cell media to reduce ice formation and thereby prevent cell death during the freezing process. +
'''Dinitrochlorobenzene (1-chloro-2,4-dinitrobenzene)''' (DNCB) is a glutathione (GSH) inhibitor. +
'''2,4-dinitrophenole''' (C<sub>6</sub>H<sub>4</sub>N<sub>2</sub>O<sub>5</sub>; M = 184.11 g·mol<sup>-1</sup>) is a protonophore acting as an [[uncoupler]] of [[oxidative phosphorylation]]. +
A '''directive''' is a legal act of the European Union, which requires member states to achieve a particular result without dictating the means of achieving that result. +
The '''Directory of Open Access Journals''' is a free online directory that indexes and provides access to open access peer-reviewed journals. +
In a '''discontinuous system''', gradients in [[continuous system]]s across the length, ''l'', of the diffusion path [m], are replaced by differences across compartmental boundaries of zero thickness, and the local concentration is replaced by the free activity, ''α'' [mol·dm<sup>-3</sup>]. The length of the diffusion path may not be constant along all diffusion pathways, spacial direction varies (''e.g.'', in a spherical particle surrounded by a semipermeable membrane), and information on the diffusion paths may even be not known in a discontinuous system. In this case (''e.g.'', in most treatments of the [[protonmotive force]]) the diffusion path is moved from the (ergodynamic) isomorphic [[force]] term to the (kinetic) [[mobility]] term. The synonym of a discontinuous system is '''compartmental''' or discretized system. In the first part of the definition of discontinuous systems, three compartments are considered: (1) the source compartment A, (2) the sink compartment B, and (3) the internal barrier compartment with thickness ''l''. In a two-compartmental description, a system boundary is defined of zero thickness, such that the barrier comparment (''e.g.'', a semipermeable membrane) is either part of the system (internal) or part of the environment (external). Similarly, the intermediary steps in a chemical reaction may be explicitely considered in an ergodnamic multi-comparment system; alternatively, the kinetic analysis of all intermediary steps may be collectively considered in the catalytic reaction ''mobility'', reducing the measurement to a two-compartmental analysis of the substrate and product compartments. +
A '''dispersion device''' diffracts light at different angles according to its wavelength. Traditionally, prisms and [[diffraction gratings]] are used, the latter now being the most commonly used device in a [[spectrofluorometer]] or [[spectrophotometer]]. +
'''Display DatLab help'''
In this section, we present some issues that could happen during your data analysis related to the graphs display and how to fix them quickly.
Case in which an issue might occur:
::* While analysing your data, trying to close the program while the graph is still being loaded. If you cancel the closing window, the graph will not be loaded at the screen.
In the event of a frozen display of the graphs, try the alternatives below:
::* Click on: Graph > Autoscale time axis
::* Click on: Graph > Scaling (F6); then press OK to confirm the scaling and induce the program to reload the graphs (no changes in the graphs are required). +
The Power-O2k number, which is set in the pull-down menu Oroboros O2k \ [[O2k configuration]], is shown in the active graph. To show it in graphs copied to clipboard, the option "Show Oroboros icon in clipboard files" must be enabled in the Graph-menu [[Graph options - DatLab]]. +
If '''Display numerical value''' the current numerical values are displayed in the graph for the active plots on the Y1 axis and Y2 axis (during data acquisition only). +
The sodium salt of '''Dithionite''' Na<sub>2</sub>S<sub>2</sub>O<sub>4</sub> (Dit) is the 'zero oxygen solution powder' used for [[Oxygen calibration - DatLab |calibration of oxygen sensors]] at [[Zero calibration | zero oxygen concentration]], or for stepwise reduction of oxygen [[concentration]]s in [[MiPNet14.06 Instrumental O2 background |instrumental O<sub>2</sub> background tests]]. It is not recommended to use dithionite in experiments with biological samples or several multisensor approaches, for these see [[Setting the oxygen concentration]]. +
The most common cause of '''drift''' is variation in the intensity of the [[light source]]. The effect of this can be minimised by carrying out a [[balance]] at frequent intervals. +
If a sample contains a number of absorbing substances, it is sometimes possible to select discrete pairs of wavelengths at which the change in [[absorbance]] of a particular substance (due to oxidation or reduction, for example) is largely independent of changes in the [[absorbance]] of other substances present. '''Dual wavelength analysis''' can be carried out for [[cytochrome c]] by subtracting the [[absorbance]] at 540 nm from that at 550nm in order to give a measure of the degree of reduction. Similarly, by subtracting the [[absorbance]] at 465 nm from that at 444 nm, an indicator of the [[redox state]] of [[Complex IV | cytochrome ''aa''<sub>3</sub>]] can be obtained. +
[[Electron-transfer-pathway state |ET-pathway level 2]] is supported by '''duroquinol''' DQ feeding electrons into Complex III (CIII) with further electron transfer to CIV and oxygen. Upstream pathways are inhibited by rotenone and malonic acid in the absence of other substrates linked to ET-pathways with entry into the Q-junction. +
'''Dyscoupled respiration''' is [[LEAK respiration]] distinguished from intrinsically (physiologically) uncoupled and from extrinsic experimentally [[Uncoupler|uncoupled]] respiration as an indication of extrinsic uncoupling (pathological, toxicological, pharmacological by agents that are not specifically applied to induce uncoupling, but are tested for their potential dyscoupling effect). Dyscoupling indicates a mitochondrial dysfunction.
In addition to intrinsic uncoupling, dyscoupling occurs under pathological and toxicological conditions. Thus a distinction is made between physiological uncoupling and pathologically defective dyscoupling in mitochondrial respiration. +
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