(a.) Of no legal or binding force or validity; of no efficacy; invalid; void; nugatory; useless.
(n.) Something that has no force or meaning.
(n.) That which has no value; a cipher; zero.
(v. t.) To annul.
(n.) One of the beads in nulled work.
Example Sentences:
(1) Measurements of acetylcholine-induced single-channel conductance and null potentials at the amphibian motor end-plate in solutions containing Na, K, Li and Cs ions (Gage & Van Helden, 1979; J. Physiol.
(2) DR(+) cells, however, showed no change in percentage and a lesser drop in absolute numbers, suggesting an increase with advancing disease of DR(+), Ig(-) null cells, which may represent immature B cell precursors.
(3) In this report we describe an improvement upon the design by Stanton and Lightfoot for a simple photographic null method to determine the kVp of a diagnostic region x-ray source.
(4) At least two (Rh null and the McLeod type) are responsible for congenital hemolytic disorders.
(5) (2) Sequences of brightness steps of like polarity (either increments or decrements) elicit positive and negative motion-dependent response components when mimicking motion in the cell's preferred and null direction, respectively.
(6) The analysis also involved statistical tests of a modified null hypothesis, the generation of confidence intervals (CIs) and a meta-analysis.
(7) The null potential of both responses became more and less negative with a decrease and an increase, respectively, in the extracellular potassium concentration.
(8) The null mutation of algR was generated in a mucoid derivative of the standard genetic strain PAO responsive to different environmental factors.
(9) Endoneurial fluid pressure (EFP) was recorded by an active, servo-null pressure system after a glass micropipette was inserted into rat sciatic nerve undergoing wallerian degeneration.
(10) In thymo-deprived mice (nude mice and B mice) the percentage of null cells increases during the stage of regeneration, and B mice develop a large number of Ig +-bearing cells.
(11) Alkaline phosphatase activity was elevated in the lymphocytes from T-CLL, cord blood and tonsils and the blast cells from Null-ALL.
(12) Analysis of ldlA cells has identified three classes of mutant alleles at the ldlA locus: null alleles, alleles that code for normally processed receptors that cannot bind LDL, and alleles that code for abnormally processed receptors.
(13) Putative null sup-38 mutations cause maternal-effect lethality which is rescued by a wild-type copy of the locus in the zygote.
(14) Null cells of patients with hypoplastic anemia did not produce erythroid colonies under any culture conditions.
(15) Comparison of simulated versus actual inheritance data demonstrates that the so-called null structural alleles actually produce functional globins.--The genetic controls in Peromyscus may be analogous to those in primates.
(16) A null zone and associated sudden phase-reversal of RSA were observed in stratum lucidum of CA3.
(17) When the stimulus is placed at a position approximately 80 degrees dorsal to the eye axis, there is no response; this area is called the null region.
(18) Northern blot analysis showed that Adh-1 mRNA was synthesized at wild-type levels in immature seeds of the null mutant, but dropped to 25% in mature seeds.
(19) Two tumours were null cell adenomas with PIs less than 0.1 and 0.2%.
(20) Thus this methodology offers the potential to study naturally occurring ADH electromorphs and null alleles independent of enzymatic activity assays.
Perturbation
Definition:
(n.) The act of perturbing, or the state of being perturbed; esp., agitation of mind.
(n.) A disturbance in the regular elliptic or other motion of a heavenly body, produced by some force additional to that which causes its regular motion; as, the perturbations of the planets are caused by their attraction on each other.
Example Sentences:
(1) These membrane perturbation effects not observed with bleomycin-iron in the presence of a hydroxyl radical scavenger, dimethyl thiourea, or a chelating agent, desferrioxamine, were correlated with the ability of the complex to generate highly reactive oxygen species.
(2) Ultraviolet difference spectrophotometry indicates that the inactivated enzyme retains its capacity for binding the nucleotide substrates whereas the spectral perturbation characteristic of 3-phosphoglycerate binding is abolished in the modified enzyme.
(3) It is suggested that laboratory experiments should be performed on perturbed systems only if simulations have shown that the methods of data analysis will be satisfactorily powerful and accurate.
(4) Thresholds were measured for detecting perturbations in a regular lattice of dots by modulating local dot density, local dot luminance, or some combination of the two.
(5) It is shown that when a constant current is applied such that a stable equilibrium and rhythmic firing are present, the following predictions are inherent in the HH system of equations: (a) Small instantaneous voltage perturbations to the axon given at points along its firing spike result in phase resetting curves (when new phase versus old phase is plotted) with an average slope of 1.
(6) Lower lip perturbation duration was manipulated to yield two different load conditions.
(7) The role of the Golgi complex in the post-translational oligosaccharide maturation of alpha-amylase was explored by use of the carboxylic ionophore, monensin (10(-7)M), a known perturbant of the structure and function of the Golgi complex.
(8) The importance of the ionic interaction due to the formation of the salt bridge between the Asp-27 and the pteridine ring in Escherichia coli dihydrofolate reductase-methotrexate complex has been studied by using the free-energy perturbation method.
(9) Presence of the monosynaptic reflex during platform perturbations at normal latencies suggests that balance problems in children with Down syndrome do not result from hypotonia, which researchers have defined as decreased segmental motoneuron pool excitability and pathology of stretch reflex mechanisms, but rather result from defects within higher level postural mechanisms.
(10) We have perturbed the dynamics of the nuclear lamins by means of cell fusion between mitotic and interphase cells and have studied redistribution of lamins in fused cells as a function of extracellular pH levels.
(11) In the coagulating gland, this compensatory response involved the proliferation of many cells which, in the absence of cytotoxic perturbation, would be non-proliferatie (Q cells).
(12) The effect of initial perturbation of the thrombus by a guide wire appears to be less important than the thrombus disruption and accelerated thrombolysis caused by the pulsatile delivery system.
(13) As before, subjects were instructed to either oppose the perturbation (Predictable Oppose) or relax the forearm muscles (Predictable Let-Go).
(14) Bivalent cations (Ca2+, UO2(2+) or Zn2+) in the subphase at pH 5.6 significantly modified the behaviour of mixed monolayers of fusogenic lipids with phospholipids; there was a parallel perturbing effect of fusogenic lipids on interactions between monolayers of phospholipids and bivalent cations.
(15) In particular, nitration of Tyr-51 provoked a structural perturbation in the globular region.
(16) Altering the biophysical characteristics of cell membranes by diet and membrane perturbing agents markedly influences thermosensitivity of cells.
(17) Paraphilias (PAs) and non-paraphilic sexual addictions (NPSAs) may be behaviors that share a common perturbation of central serotonin neuroregulation as a component of their pathophysiology.
(18) Two functions of these have been proposed: 1) that they are compatible osmolytes which regulate cell volume (against high external NaCl) without inhibiting proteins and 2) that methylamines (GPC and betaine) are counteracting osmolytes which stabilize proteins against perturbation from high renal urea.
(19) This high incidence of HER2 gene amplification with accompanying overexpression in non-invasive breast tumors suggests that perturbations of the HER2 oncogene are among the earliest and most common genetic lesions in human breast cancer.
(20) Hypophysectomy was selected as a model system for perturbing testicular cell types, since the cytological sequelae of this treatment post-hypophysectomy in the rat are well documented in the literature.