Property:Description
From Bioblast
This is a property of type Text.
L
A '''Layout''' in [[DatLab]] selected in the Layout menu yields a standardized display of graphs and [[Plot - DatLab |plots]] displayed with specific [[Scaling - DatLab|scalings]]. The graph layout defines initial settings, which can be modified for plots [Ctrl+F6] and scaling [F6]. A modified layout can be saved as user layout without changing the standard layouts. +
This method makes use of all of the data points of the spectrum in order to quantify a measured spectrum with a reference spectrum of known concentration using a '''least squares method''' to match the measured spectrum with the reference spectrum. The technique results in improved accuracy compared with the use of only a few characteristic wavelengths. +
'''Length''' ''l'' is an SI base quantity with SI base unit [[meter]] m. Quantities derived from length are [[area]] ''A'' [m<sup>2</sup>] and [[volume]] ''V'' [m<sup>3</sup>]. Length is an extensive quantity, increasing additively with the number of objects. The term 'height' ''h'' is used for length in cases of vertical position (see [[height of humans]]). Length of height per object, ''L''<sub>''U''<sub>''X''</sub></sub> [m·x<sup>-1</sup>] is length per unit-entity ''U''<sub>''X''</sub>, in contrast to lentgth of a system, which may contain one or many entities, such as the length of a pipeline assembled from a number ''N''<sub>''X''</sub> of individual pipes. Length is a quantity linked to direct sensory, practical experience, as reflected in terms related to length: long/short (height: tall/small). Terms such as 'long/short distance' are then used by analogy in the context of the more abstract quantity [[time]] (long/short duration). +
[[File:E.jpg |link=ET capacity]] '''Level flow''' is a [[steady state]] of a system with an input process coupled to an output process (coupled system), in which the output force is zero. ''Clearly, energy must be expended to maintain level flow, even though output is zero'' (Caplan and Essig 1983; referring to zero output force, while output flow may be maximum). +
A variety of '''light sources''' are available for [[fluorometry]] and [[spectrophotometry]]. These include deuterium, mercury and xenon arc lamps and quartz halogen bulbs dependent upon the wavelengths required. However, the advent of [[light emitting diode]]s has greatly increased the possibilities for the application of [[fluorometry]] and [[spectrophotometry]] to areas that were previously not practicable, and at a much reduced cost. +
A '''light-emitting diode''' (LED) is a light source (semiconductor), used in many every-day applications and specifically in [[fluorometry]]. LEDs are available for specific spectral ranges across wavelengths in the [http://en.wikipedia.org/wiki/Light-emitting_diode#Colors_and_materials visible, ultraviolet, and infrared range]. +
'''Light-enhanced dark respiration''' ''LEDR'' is a sharp (negative) maximum of dark respiration in plants in response to illumination, measured immediately after switching off the light. ''LEDR'' is supported by respiratory substrates produced during photosynthesis and closely reflects light-enhanced [[photorespiration]] (Xue et al 1996). Based on this assumption, the total photosynthetic oxygen flux ''TP'' is calculated as the sum of the measured net photosynthetic oxygen flux ''NP'' plus the absolute value of ''LEDR''. +
'''Lightguides''' consist of optical fibres (either single or in bundles) that can be used to transmit light to a sample from a remote [[light source]] and similarly receive light from a sample and transmit it to a remote [[detector]]. They have greatly contributed to the range of applications that for which optical methods can be applied. This is particularly true in the fields of medicine and biology. +
The '''limiting oxygen pressure''', ''p''<sub>l</sub>, is defined as the partial oxygen pressure, ''p''<sub>O2</sub>, below which [[anaerobic]] catabolism is activated to contribute to total ATP generation. The limiting oxygen pressure, ''p''<sub>l</sub>, may be substantially lower than the '''[[critical oxygen pressure]]''', ''p''<sub>c</sub>, below which [[aerobic]] catabolism (respiration or oxygen consumption) declines significantly. +
In the transition from aerobic to [[anaerobic | anaerobic metabolism]], there is a limiting ''p''<sub>O2</sub>, ''p''<sub>lim</sub>, below which anaerobic energy flux is switched on and [[Calorespirometric ratio|CR ratios]] become more exothermic than the [[oxycaloric equivalent]]. ''p''<sub>lim</sub> may be significanlty below the [[critical pO2|critical ''p''<sub>O2</sub>]]. +
'''Linear phenomenological laws''' are at the core of the thermodynamics of irreversible processes TIP, considered to apply near equilibrium but more generally in transport processes (e.g. Fick's law). In TIP, linearity is discussed as the dependence of generalized flows ''I'' or fluxes ''J'' on generalized forces, ''J'' = -''L''·''F'', where ''L'' is expected to be constant (as a prerequisite for linearity) and must not be a function of the force ''F'' ([[affinity]]) for [[Onsager 1931 Phys Rev |Onsager reciprocity]] to apply. This paradigm is challenged by the [[ergodynamics |ergodynamic concept]] of fundamentally non-linear isomorphic flux-[[force]] relations and is replaced by the generalized isomorphic flux-[[pressure]] relations. Flows ''I'' [MU·s<sup>-1</sup>] and forces ''F'' [J·MU<sup>-1</sup>] are conjugated pairs, the product of which yields power, ''I''·''F'' = ''P'' [J·s<sup>-1</sup> = W]. Flux ''J'' is system-size specific flow, such that volume-specific flux times force yields volume-specific power, ''P''<sub>''V''</sub> = ''J''·''F'' [W·m<sup>-3</sup>]. Then [[Vector |vectoral]] and [[Discontinuous system |vectorial]] transport processes are inherently non-linear flux-force relationships, with '''''L''''' = '''''u'''''·'''''c''''' in continuous transport processes along a gradient ('''''c''''' is the local concentration), or ''L'' = ''u''·''α'' (''α'' is the [[free activity]] in a discontinuous transport process across a semipermeable membrane) — formally not different from (isomorphic to) [[scalar]] chemical reactions. +
'''Linearity''' is the ability of the method to produce test results that are proportional, either directly or by a well-defined mathematical transformation, to the concentration of the analyte in samples within a given range. This property is inherent in the [[Beer-Lambert law]] for [[absorbance]] alone, but deviations occur in [[scattering]] media. It is also a property of [[fluorescence]], but a [[fluorophore]] may not exhibit linearity, particularly over a large range of concentrations. +
[[Armstrong 2010 J Comp Physiol B]]: This paper describes a method for purification of rodent liver mitochdondria using relatively low-speed centrifugation through discontinuous Percoll gradients. +
With '''Living Communications''', [https://www.bioenergetics-communications.org/index.php/bec Bioenergetics Communications] (BEC) takes the next step from pre-print to re-print. The concept of ''Living Communications'' pursues a novel culture of scientific communication, addressing the conflict between long-term elaboration and validation of results versus sharing without delay improved methods and preliminary findings. Following the preprint concept, updates may be posted on the BEC website of the resource publication. Updated versions of Living Communications are submitted for Open Peer Review with full traceability. In contrast to static papers, evolution of ''Living Communications'' is more resourceful and efficient than a ‘new’ publication. ''Living Communications'' provide a pathway along the scientific culture of lively debate towards tested and trusted milestones of research, from pre-print to re-print, from initial steps to next steps. +
Cell viability in '''living cells''' should be >95 % for various experimental investigations, including cell respirometry. Viable cells (vce) are characterized by an intact plasma membrane barrier function. The total cell count (''N''<sub>ce</sub>) is the sum of viable cells (''N''<sub>vce</sub>) and dead cells (''N''<sub>dce</sub>). In contrast, the plasma membrane can be permeabilized selectively by mild detergents ([[digitonin]]), to obtain the [[Mitochondrial preparations |mt-preparation]] of [[permeabilized cells]] used for [[cell ergometry]]. Living cells are frequently labelled as ''intact cells'' in the sense of the total cell count, but ''intact'' may suggest dual meanings of ''viable'' or unaffected by a disease or mitochondrial injury. +
A '''Lower O2 limit [µM]''' can be defined for each O2k-chamber, to trigger an automatic warning when the experimental O<sub>2</sub> concentration drops below this limit. It reminds the user that re-oxygenation of the O2k-chamber may be required. For the lower O<sub>2</sub> concentration limit, the [[critical oxygen pressure |critical oxygen concentration]] should be considered, which differs between isolated mitochondria, large cells, and permeabilized muscle fibers. A higher limit should be chosen when high oxygen flux is expected, e.g. prior to uncoupler titration. A lower limit is acceptable prior to inhibition of respiration causing low oxygen flux. +
'''Luminescence''' is spontaneous emission of radiation from an electronically or vibrationally excited species not in thermal equilibrium with its environment (IUPC definition). An alternative definition is "Luminescence is emission of
light by a substance not resulting from heat." Luminescence comprises many different pehnomena. Luminescence from direct photoexcitation of the emitting species is called photoluminescence. Both [[fluorescence]] and [[phosphorescence]] are forms of photoluminescence. In biomedical research also forms of chemiluminescence (e.g.the luciferin reaction) are used. In chemiluminescence the emission of radiation results from a chemical reaction. For other forms of luminescence see [http://goldbook.iupac.org/L03641.html the IUPAC Gold Book]. +
M
[[File:MITOEAGLE-representation.jpg|150px|left]]
The objective of the '''MitoEAGLE''' network is to improve our knowledge on mitochondrial function in health and disease related to Evolution, Age, Gender, Lifestyle and Environment. +
'''Magnesium Green''' (MgG) is an [[extrinsic fluorophores|extrinsic fluorophore]] that fluoresces when bound to Mg<sup>2+</sup> and is used for measuring mitochondrial ATP production by [[mitochondrial preparations]]. Determination of mitochondrial ATP production is based on the different dissociation constants of Mg<sup>2+</sup> for [[ADP]] and [[ATP]], and the exchange of one ATP for one ADP across the mitochondrial inner membrane by the [[adenine nucleotide translocase]] (ANT). Using the dissociation constants for ADP-Mg<sup>2+</sup> and ATP-Mg<sup>2+</sup> and initial concentrations of ADP, ATP and Mg<sup>2+</sup>, the change in ATP concentration in the medium is calculated, which reflects mitochondrial ATP production. +
[[File:Malic_acid.jpg|left|100px|Malic acid]]
'''Malic acid''', C<sub>4</sub>H<sub>6</sub>O<sub>5</sub>, occurs under physiological conditions as the anion '''malate<sup>2-</sup>, M''', with p''K''<sub>a1</sub> = 3.40 and p''K''<sub>a2</sub> = 5.20. L-Malate is formed from fumarate in the [[TCA cycle]] in the mitochondrial matrix, where it is the substrate of [[malate dehydrogenase]] oxidized to [[oxaloacetate]]. Malate is also formed in the cytosol. It cannot permeate through the lipid bilayer of membranes and hence requires a carrier ([[dicarboxylate carrier]], [[tricarboxylate carrier]] and 2-oxoglutarate carrier). Malate alone cannot support respiration of [[Mitochondrial preparations|mt-preparations]] from most tissues, since oxaloacetate accumulates in the absence of [[pyruvate]] or [[glutamate]].
Malate is a [[NADH electron transfer-pathway state |type N substrate]] (N) required for the [[Fatty acid oxidation pathway control state| FAO-pathway]]. In the presence of [[Malate-anaplerotic pathway control state|anaplerotic pathways]] (''e.g.'', [[Malic enzyme|mitochondrial malic enzyme, mtME]]) the capacity of the FAO-pathway can be overestimated due to a contribution of NADH-linked respiration, F(N) (see [[SUIT-002]]). +
