A. Glossary of the key notions in Bionics and beyond
15. L
Lactams → ~ are cyclic amides of amino
carboxylic acids, having a 1-azacycloalkan-2-one structure, or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring.
Lactones → ~ are cyclic esters of hydroxy
carboxylic acids, containing a 1-oxacycloalkan-2-one structure, or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring.
Lactose → The disaccharide of the milk,
containing glucose and galactose
Lagrange → Joseph-Louis Lagrange (1736–1813),
born Giuseppe Lodovico (Luigi) Lagrangia, was a mathematician and astronomer, making significant contributions to all fields of analysis, to number theory, and to classical and celestial mechanics.
Lagrange-multiplier → The method of Lagrange multipliers
provides a strategy for finding the maxima and minima of a (multivariable) function subject to constraints. The method of Lagrange multipliers yields a necessary condition for optimality in constrained problems.
Lagrangian mechanics → ~ is a re-formulation of classical
mechanics that combines conservation of momentum with conservation of energy. It was introduced by the French mathematician Joseph-Louis Lagrange. In Lagrangian mechanics, the trajectory of a system of particles is derived by solving the Lagrange equations in one of two forms, either the Lagrange equations of the first kind, which treat constraints explicitly as extra equations, often using Lagrange multipliers; or the Lagrange equations of the second kind, which incorporate the constraints directly by judicious choice of generalized coordinates. The fundamental lemma of the calculus of variations shows that solving the Lagrange equations is equivalent to finding the path for which the action functional is stationary, a quantity that is the integral of the Lagrangian over time.
Laplace transform → The ~ is an integral transform
perhaps second only to the Fourier transform in its utility in solving physical problems. The ~ is particularly useful in solving linear ordinary differential equations with constant coefficients such as those arising in the analysis of electronic circuits.
Larmour-frequency → The ~ is the frequency or rate of
precession of the nuclear magnetic moment (spins) and is proportional to the magnetic field strength as shown in the Larmor equation: f= -gBo/2pi where f is the ~ in Hertz, g is the gyromagnetic ratio of the nucleus, and Bo is the magnetic field strength.
Laser → Light Amplification by Stimulated
Emission of Radiation, emits light (electromagnetic radiation) - with high degree of spatial and temporal coherence, - through a process of optical amplification based on the stimulated emission of photons.
Laser tweezer → Optical tweezers (originally called
―single-beam gradient force trap‖) are scientific instruments that use a highly-focused laser beam to provide an attractive or repulsive force (typically on the order of piconewtons), depending on the refractive index mismatch to physically hold and move microscopic dielectric objects, neutral molecules.
Late wave → After stimulating a motor or a mixed
Lateral geniculate nucleus → A part of the metathalamus, which serves as a relay nucleus within the visual pathway.
Lateral grasp → Grasp with thumb and index finger
to hold smaller objects.
Lateral inhibition → The reduction of the neuronal
activity in the neighbourhood of an excited neuron.
Lateral plane → A ~ is an Y-Z plane, perpendicular to
the ground, which separates left from right (in standard Descartes coordinate system)
Law of mass action → A model predicting the equilibrium
concentrations of reactants and products in a reversible reaction.
Laws of nature → Natural law or the law of nature has
been described as a law whose content is set by nature and that therefore is universal. Natural law is often conflated with common law. It is a scientific generalization based on empirical observations of physical behaviour. Laws of nature are observable. Empirical laws are typically conclusions based on repeated scientific experiments and simple observations, and which have become accepted universally within the scientific community.
Layered Communication Approaches → ~ is a a conceptual framework of standards for communication in the network across different equipment and applications by different vendors.
The network communication protocols used today have a structure based on the layered model.
Layout → Planar view of polygons representing
a circuit.
LCAO (Linear Combination of Atomic Orbitals) A1279method → ~ is a quantum superposition of atomic orbitals and a technique for calculating molecular orbitals in quantum chemistry. In mathematical sense, wave functions are the basis set of functions, the basis functions, which describe the electrons of a given atom.
In chemical reactions, orbital wavefunctions are modified, i.e. the electron cloud shape is changed, according to the type of atoms participating in the chemical bond.
LCAO-MO theory → ~ is a theory that describes a linear
combination of atomic orbitals that produces molecular orbitals
Lead compound → In drug discovery a ~ is a chemical
compound that has pharmacological or biological activity and whose chemical structure is used as a starting point for chemical modifications in order to improve potency, selectivity, or pharmacokinetic parameters.
Leakage current → Current flowing along the
penetrating intracellular electrode between the intracellular and extracellular spaces.
Learning procedure → The procedure when a free
parameters are tuned to perform a special task
Learning rule → Algorithm, which uploads the
program of the network
Least action principle → The principle of least action – or, more accurately, the principle of stationary action – is a variational principle that, when applied to the action of a mechanical system, can be used to obtain the equations of motion for that system.
Least-square minimization algorithm → A method to approximate the solution of overdetermined equation systems. The overall solution gained from this method minimizes the sum of the squares of the errors made in solving every single equation.
Leaving (signal) → A signal is leaving if it only has 0 values for time instants greater or equal then 0.
Leksell stereotactic system → Human stereotactic apparatus based on polar coordinate system invented by Lars Leksell Swedish neurosurgeon
Leksell SurgiPlan → Computer based surgical planning
system based on fusion of CT, MR and other imaging texhniques and the Leksell stereotactic apparatus
Lenard → Philipp Eduard Anton von Lenard
(1862–1947), Lénárd Fülöp Eduárd Antal, was a German physicist (1905 Nobel Prize for his research on cathode rays).
Lenard – Einstein → Lénard found the energies of the
emitted electrons concerning of the photoelectronic effect to be independent of the intensity of the incident radiation. In Einstein‘s model, increasing the frequency, rather than the intensity, of the incident radiation would increase the average energy of the emitted electrons.
Length constant → The distance in which the 63% of the
maximal action potential is reached. The greater the length constant, the farther the AP has effect.
Lennard-Jones potential → Is a model of the van der Waals interaction between two atoms. It depicts the potential energy as a function of the distance between them.
Lepton → A ~ is an elementary particle and a
fundamental constituent of matter. The best known of all leptons is the electron which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos).
There are six types of leptons (electrons and electron neutrinos, muons and muon neutrinos, taus and tau neutrinos). Leptons have various intrinsic properties, including electric charge, spin, and mass. Unlike quarks however, leptons are not subject to the strong interaction, but they are subject to the other three fundamental interactions: gravitation, electromagnetism (excluding neutrinos, which are electrically neutral), and the weak interaction.
Lesion → A pathological change in the tissue,
which is caused either by disease, injury or trauma.
Level Crossing Rate (LCR) → The rate at which the fieldstrength electron pair acceptors and bases as electron pair donors
Lewis formula (Lewis structure) → ~ (or Lewis structure) is a molecular structure in which the valency electrons are shown as dots so placed between the bonded atoms that one pair of dots represents two electrons or one covalent (single) bond, e.g. A double bond is represented by two pairs of dots, etc. Dots representing non-bonded outer-shell electrons are placed adjacent to the atoms with which they are associated, but not between the atoms. Formal charges (e.g. +, −, 2+, etc.) are attached to atoms to indicate the difference between the positive nuclear charge (atomic number) and the total number of electrons (including those in the inner shells), on the formal basis that bonding electrons are shared equally between atoms they join.
(Bonding pairs of electrons are usually denoted by lines, representing covalent bonds, as in line formulae.)
Leyden jar → A device used to store static
electricity. It was the first capacitor invented by Pieter van Musschenbroek (1692-1761) in 1746.
Liftoff → The process is useful for patterning
materials that cannot be etched without affecting underlying materials on the substrate.
Ligand → A small molecule which can bind to
a bigger one, for example a receptor.
Ligand-gated carriers → Carriers opening of which depends on the binding some ligand.
Ligand-gated ion channel → Ion channel that require certain molecules attached to them in order to open.
Primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization, while its speed, about 3×108 m/s in a vacuum, is one of the fundamental constants of nature. Light, which is emitted and absorbed in tiny ―packets‖, called photons, exhibits properties of both waves and particles.
This property is referred to as the wave–particle duality.
Likelyhood function → Density function of outcome if
obersavations are known
Limb (Neoromorph movement control) → Is an object containing different segments(links) connected to each other via joints. Joints are capable of rotating around joints.
Limited support (signal) → A signal has a limited support if there exist two time instants, say t1<t2 and for times earlier then t1 the function is 0 and for times later then t2 the signal is also 0. in between it can have arbitrary values.
Linear combination of atomic orbitals → A linear combination is a quantum superposition and a technique for calculating. In quantum mechanics, electron configurations of atoms are described as wavefunctions. In mathematical sense, these wave functions are the basis set of functions, the basis functions, which describe the electrons of a given atom. An initial assumption is that the number of molecular orbitals is equal to the number of atomic orbitals included in the linear expansion. The coefficients are the weights of the contributions of the n atomic orbitals to the molecular orbital.
Linear operator → A ~ is a mapping from one linear
vector space to another (or itself), obeying two rules: additivity and homogenity
Linear phase (filter) → a filter which has a ~ characteristics
Linear polarization → Polarization (also polarisation) is a property of certain types of waves that describes the orientation of their oscillations. Electromagnetic waves exhibit polarization. By convention, the polarization of waves is described by specifying the orientation of the wave‘s electric field at a point in space over one period of the oscillation. If the electric field is oriented in a single direction, we say about linear polarization.
Linear range → The part of the forward range, where
the voltage-current function can be approximated linearly.
Linear separability → Two point sets are linearly separable
in n-dimensional space if they can be separated by a hyperplane.
Line-of-sight (LoS) → There are no obstructions between
the transmitter and receiver and the signal propagates along a straight line between the two.
Link budget → It is the accounting of all of the gains
and losses in a wireless link from the transmitter, through the wireless medium to the receiver.
Lipase → A hydrolase which cleaves the ester
bonds in lipids (triacylglycerol, phospholipid)
Lipid → A compound extractable from tissues with non-polar solvents
Lipid bilayer → The general structure of biological
membranes. It is constituted by two layers of lipids which face to each other by their hydrophobic part while to water they face by their hydrophilic head.
Lipids → A group of organic compounds.
Lipids are at least partly hydrophobic.
Lipoprotein → Multimolecular complex of protein,
phospholipid and cholesterol that encloses a core composed of triacylglycerols, phospholipids and other lipids
Lipoprotein lipase → Lipase which hydrolyzes
triacylglycerol and phospholipds in plasma lipoproteins (VLDL and chylomicrons)
Liquid → Liquids are composed of particles
that are loosely associated and freely moving. Liquids have definite volume, but no definite shape.
Liquid-liquid Extraction/Washing → ~ method by which material is selectively transferred from one into the other phase of mixture of two immiscible solvents.
Lissauer zone → Nerve tract surrounding the tip of the
posterior horn of the spinal cord
Lithography → ~ is the process of transferring an
image from a pattern onto a surface by using light. In the manufacture of semiconductors, it is the process that predefines the device features on the silicon wafer prior to the etch process steps.
Load error → The internal resistance of a voltmeter
influences the measurements, this is called ~.
Load line → The ~ represents the relationship
between current and voltage in the linear part of the circuit.
Local aligment → Finds sections of the sequences
(conserved regions) with significant similarity
Local connection → In the neural network only a few
neuron in a local area are connected to each other
Local field potential (LFP) → Electrophysiological signal which is dominated by the electrical current flowing from all nearby dendritic synaptic activity within a volume of tissue.
A voltage is produced by the summed synaptic current flowing across the resistance of the local extracellular space.
Local rules → Local, pixel-level rule of a given task
Local/Global Descriptors → Descriptors that refer to a part of the structure are called local (a protein domain). Descriptors that refer to the entire structure (say protease) is a global descriptor.
Lock and key hypothesis → A model for substrate binding where
the binding is based on the complementarity of the shape of substrate binding surface of the enzyme and the shape of the substrate.
Locked-in syndrome (LIS) → ~ is a condition in which a patient is aware and awake but cannot move or communicate verbally due to complete paralysis of all voluntary muscles in the body.
Locus coeruleus → A nucleus in the brainstem, which
contains neurons producing norepinephrine and participate in stress-regulation.
Logarithmic quantization → The logarithmic implies here the range of the input values that map to each output value has a logaritmic relationship with the output value.
Logical product (VLSI design) → The common part of two sets (A és B), their logical product, intersection or conjunction are the elements that are simultaneously the elements of A and B. In mathematical logic it would be a conjuction.
Logical sum (VLSI design) → The elements that belong to set A or set B or both of them constitute the logical sum, or union of the two sets. In mathematical logic it would be a disjunction,
Long Term Evolution (LTE) → It is a 4G wireless broadband
technology developed by the Third Generation Partnership Project (3GPP), an industry trade group.
Long-term depression (LTD) → ~ is a weakening of a synapse after a short series of presynaptic action potentials or asynchronous presynaptic and postsynaptic activity.
Long-term memory → A high-capacity part of the memory
system in humans and other animals that stores information for extended time periods (from hours up to decades) and depends on enduring changes in synaptic efficacy and cellular properties.
Long-term potentiation (LTP) → Long-lasting enhancement in signal transmission between two neurons that results from stimulating them synchronously.
Loops → Non periodic, mainly unstructured
secondary structural elements with a wide range of length.
Lorentz → Hendrik Antoon Lorentz (1853–
1928) was a Dutch physicist (shared Nobel Prize in 1902) He derived the transformation equations subsequently used by Albert Einstein to describe space and time.
Lorentz force → The ~ is the force on a point charge
due to electromagnetic fields. A positively charged particle will be accelerated in the same linear orientation as the electric field, but will curve perpendicularly to both the instantaneous velocity vector and the magnetic field according to the right-hand rule. The ~ law has a close relationship with Faraday‘s law of induction.
Lorenz → Ludvig Valentin Lorenz (1829–
1891) was a Danish mathematician and physicist. The Lorenz condition is a Lorentz invariant condition.
Lorenz gauge/Lorenz condition → The ~ is used in calculations of time-dependent electromagnetic fields through retarded potentials. The gauge fixing (choosing a gauge) denotes a mathematical procedure for coping with redundant degrees of freedom in field variables.
Low energy physics → Nonrelativistic physics ~ relativistic
effects are neglible.
Lowest possible energy levels → For filling an atom with electrons in the ground state, the lowest energy levels are filled first and consistent with the Pauli exclusion principle, Low-frequency TMS (slow TMS) → Repetition rate below 1 Hz.
Low-frequency transcranial magnetic stimulation (TMS) → ~ is a slow TMS: repetition rate of it is below 1 Hz.
Low-k Dielectric → Low-k type dielectric, which is
placed between metal layers. Low-k type forms smaller capacitors that decrease signal propagation, increase dynamic power consumption
Lowpass filter → It is a filter that passes
low-frequency signals but attenuates signals with frequencies higher than the cutoff low-frequency.
Low-pass filter → A ~ is a filter that passes low-frequency signals but attenuates signals with frequencies higher than the cutoff low-frequency. Also called high-cut filter.
Lp function space → A space of functions, where every
function is integrable in p norm.
Lp/cm → Unit of resolution measurement= line
pair(s) / cm.
LPCVD (Low-pressure chemical vapor deposition) → Low pressure is used during the growth of semiconducting materials bychemical vapor deposition (see Chemical Vapor Deposition, CVD).
LUMO Lowest (energy) unoccupied molecular orbital → ~ of a given ground state molecule where electron cannot be found. The previous energy level orbital is filled. The HOMO - LUMO energy gap is descriptive of the excitability of the molecule.
Lux-Flood acid base theory → a theory where acids are defined as oxide ion acceptors and bases as oxide ion donors
Lyapunov technique → A technique, with convergence of
nonlinear recursion can be proven
Lyase → an enzyme which catalyzes the
cleavage of bonds between two carbon atoms or between a carbon and a nitrogen atom
Lyases → Enzymes catalyzing double bond
formation and removal.