(n.) The sum of four units; four units or objects.
(n.) A symbol representing four units, as 4 or iv.
(n.) Four things of the same kind, esp. four horses; as, a chariot and four.
Example Sentences:
(1) These included bringing in the A* grade, reducing the number of modules from six to four, and a greater attempt to assess the whole course at the end.
(2) Low birth weight, short stature, and mental retardation were common features in the four known patients with r(8).
(3) It was shown in experiments on four dogs by the conditioned method that the period of recovery of conditioned activity after one hour ether anaesthesia tested 7 to 7.5 days.
(4) However, four of ten young adult outer arm (relatively sun-exposed) and one of ten young adult inner arm (relatively sun-protected) fibroblasts lines increased their saturation density in response to retinoic acid.
(5) A 61-year-old man experienced four bouts of pancreatitis in 1 year.
(6) The promoters of the adenovirus 2 major late gene, the mouse beta-globin gene, the mouse immunoglobulin VH gene and the LTR of the human T-lymphotropic retrovirus type I were tested for their transcription activities in cell-free extracts of four cell lines; HeLa, CESS (Epstein-Barr virus-transformed human B cell line), MT-1 (HTLV-I-infected human T cell line without viral protein synthesis), and MT-2 (HTLV-I-infected human T cell line producing viral proteins).
(7) In each study, all subjects underwent four replications (over two days) of one of the six permutations of the three experimental conditions; each condition lasted 5 min.
(8) Four cytotoxic antibiotics, bikaverin, duclauxine, PSX-1 and vermiculine, were examined with respect to their interference with glycolysis and respiration and their possible ionophoric or cytolytic activity.
(9) The invaginations were classified into four easily recognized types: regular, chunky, filigree, and ridge (present only in axon hillock regions).
(10) During the study period four family outbreaks and seven recurrences of infection were observed.
(11) These four antigens consisted of S of MNSs blood group, Lua of Lutheran blood group, and K and Kpa of Kell-Cellano blood group.
(12) Binding data for both ligands to the enzyme yielded nonlinear Scatchard plots that analyze in terms of four negatively cooperative binding sites per enzyme tetramer.
(13) Even so, amputation of fifteen extremities and four other major excisions were required in twelve patients.
(14) Four of the 39 ticks in our colony were infected with a spirochete; presumably, Borrelia crocidurae.
(15) Four other independent LCMV-GP2(275-289) specific H-2Db-restricted CTL clones also expressed V alpha 4 and V beta 10 gene elements.
(16) The hospital whose A&E unit has been threatened with closure on safety grounds has admitted that four patients died after errors by staff in the emergency department and other areas.
(17) Maximal covalent binding of [4,5-14C]ronidazole to DNA also required four-electron reduction, consistent with previous studies of the covalent binding of this agent to immobilized sulfhydryl groups [Kedderis et al.
(18) We investigated whether these peptides also affect the sleep EEG in humans when given intravenously by comparing polysomnographically the effects of four boluses of (1) placebo, (2) 50 micrograms GHRH or (3) 50 micrograms SRIF administered at 22.00, 23.00, 24.00 and 1.00 h to 7 male controls.
(19) Since the start of this week, markets have been more cautious, with bond yields in Spain reaching their highest levels in four months on Tuesday amid concern about the scale of the austerity measures being imposed by the government and fears that the country might need a bailout.
(20) In 14 of the patients the imaging results were checked against the histological findings of a subsequent thymectomy, which revealed four thymomas and (with the exception of one normal thymus) hyperplastic changes in all the others.
Quadruplex
Definition:
(a.) Fourfold; folded or doubled twice.
Example Sentences:
(1) However, at a 50-fold higher strand concentration, the single-stranded oligomer is gradually converted into the quadruplex.
(2) We propose a model in which duplex or hairpin forms of G-DNA are folding intermediates in the formation of either 1-, 2-, or 4-stranded quadruplex structures.
(3) There has been much recent interest in the self-association of short deoxyguanosine-rich motifs within single-stranded DNAs to generate monovalent cation modulated four-stranded helical segments called G-quadruplexes stabilized by hydrogen-bonded G-tetrad alignments.
(4) Thus the number of T residues surrounding the dG cluster might control the rigidity of the quadruplex structure.
(5) Equilibrium ultracentrifugation studies confirm that these quadruplexes are composed of two strands of d(G3T4G3).
(6) The only precedent known (to us) for a cation-specific stabilization is that seen in the quadruplex structure formed by poly I.
(7) The quadruplex, [d(TTGGGGTT)]4, is resistant to denaturation in 7 M urea, in which the Watson-Crick type d(TTGGGGTT).d(AACCCCAA) duplex dissociates.
(8) We observe well-resolved proton NMR spectra corresponding to a G-quadruplex monomer conformation predominant at 50 mM K cation concentration and a G-quadruplex dimer conformation predominant at 300 mM K cation concentration.
(9) Our results indicate that specific differences in ionic interactions can result in a switch in telomeric DNAs between intramolecular hairpin-like or quadruplex-containing species and intermolecular quadruplex structures, all of which involve G.G base pairing interactions.
(10) The possible biological function of quadruplexes is discussed.
(11) The DNA oligonucleotide d(CGCG3GCG) can form either a Watson-Crick (WC) hairpin or a parallel-stranded quadruplex structure containing six G-quartet base pair assemblies.
(12) We find that these molecules fold to form a symmetrical bimolecular and an intramolecular quadruplex, respectively.
(13) An increase in ionic strength stabilizes the single-stranded structure, so it seems to inhibit the formation of the quadruplex.
(14) Experiments on ethidium bromide binding to the oligonucleotides have shown that the oligomer anti(A-T) exists, at a low ionic strength, as a four stranded complex ("quadruplex") contains two antiparallel helices, d(A).d(T), which have a parallel orientation and are bound to one another owing to the formation of additional hydrogen bonds between nucleic acid bases.
(15) The quadruplex is stable in the presence of 40 mM K+ at micromolar DNA concentration and can be kinetically trapped as a metastable form when prepared at millimolar DNA concentration and then diluted into buffer containing 40 mM Na+.
(16) Cations stabilize the quadruplex in the order K+ greater than Ca2+ greater than Na+ greater than Mg2+ greater than Li+ and K+ greater than Rb+ greater than Cs+, indicating that K+ has an optimum ionic radius for complex formation and that ionic charge affects the extent of ion-induced stabilization.
(17) Comparison with the corresponding CD spectral characteristics suggests that the electrophoretic intensity enhancement of the intermolecular G-quadruplex band is correlated to the intensity enhancement of of the positive CD maximum at 265 nm.
(18) Similar but less dramatic enhancement of the intermolecular quadruplex band is also observed in T4.
(19) Since K+ and NH4+ are known to stabilize a parallel-stranded quadruplex structure of poly[r(I)4], we infer that the multistranded structure is a quadruplex.
(20) UV thermal denaturation curves show a single concentration-dependent transition and provide data for quantitating the thermodynamics of quadruplex formation.