(a. & adv.) Four times; quadruple; as, a fourfold division.
(n.) Four times as many or as much.
(v. t.) To make four times as much or as many, as an assessment,; to quadruple.
Example Sentences:
(1) The difference in sensitivity between laboratories for end-point titres (if one very sensitive method was excluded) was around fourfold for types 1 and 2, and ninefold for type 3.
(2) HTC.JZ1 cells were stimulated to secrete up to fourfold increased amounts of IL6 over 24 hours by treatment with lipopolysaccharides (LPS).
(3) The objectivity of the items was proved by fourfold examination of the same sample group.
(4) Involved and uninvolved psoriatic epidermal cells showed a fourfold decrease in the number of 12-HETE binding sites as compared with normal healthy individuals and patients with atopic dermatitis, while receptor affinity remained unchanged.
(5) 10% NNDEMT doubled the amount of PFA in the skin, increased fourfold the amount permeated across the skin, and increased the flux fivefold.
(6) Antibody response to group A rotavirus (RV), investigated in paired sera from 72 infants and young children with acute gastroenteritis caused by an RV infection, was diagnosed on the basis of a fourfold or greater rise in group A common RV IgG antibody titer.
(7) Eighty-eight percent of subjects receiving CVD 103-HgR mounted a significant (greater than fourfold) rise in Inaba vibriocidal titre while 68% did so for the heterologous Ogawa serotype.
(8) Paired sera from 20 humans with eastern equine encephalitis (EEE) virus infections and from 17 humans with western equine encephalitis (WEE) virus infections, all with previously demonstrated fourfold or greater rises or falls in hemagglutination-inhibiting, complement-fixing, or neutralizing antibody titers, were tested for immunoglobulin M (IgM) and IgG antibodies by an enzyme immunoassay.
(9) The Ig levels were within the normal range in patients with malignant astrocytoma and glioblastoma multiforme, whereas a three- and fourfold increase in the IgM level was observed in patients with astrocytoma.
(10) However, in the presence of 4.4, 6.6 or 8.9 x 10(-3) M glucose, the same concentration of acetylcholine stimulated insulin secretion approximately fourfold.
(11) Measurements of absolute transcript abundance show that collagen mRNA is present in blastula primary mesenchyme cells at 600-700 copies per cell and at about fourfold lower amounts in other mesenchyme cells.
(12) Forskolin (10 microM) also increases TH transcription (fourfold in 15 min) by a mechanism that is not blocked by cycloheximide.
(13) The average mitochondrial volume is increased fourfold in the peripheral and midzonal regions with a commensurate decrease in the number of mitochondria per cell.
(14) Transesophageal cardioversion decreased the defibrillation threshold three- to fourfold from that of conventional transthoracic cardioversion.
(15) Such depleted monocytes exhibit a fourfold reduction in their ability to promote both internalization of T3 and production of IL-2.
(16) In other studies, the stereoisomers of tocainide were shown to have a threefold to fourfold difference in IC50 for inhibition of [3H]BTXB binding.
(17) Plasma immunoreactive TNF was increased almost fourfold in tumor-bearing nude mice compared with control nude mice.
(18) Serum gastrin levels significantly (P less than 0.01) increased threefold to fourfold during the first 1-2 months of the study when all patients ingested 40 mg of omeprazole daily.
(19) Forty-nine serum pairs with antibody to cytomegalovirus (CMV) were evaluated for rises in antibody titer (greater than or equal to fourfold) by indirect hemagglutination (IHA) and complement fixation (CF), using a freeze-thaw antigen (FT) and a glycine extract antigen (GE).
(20) Osteocalcin secretion was measured at doses as low as 0.03 nM (fourfold increase, p less than 0.05), and this activity increased further with higher doses of 1,25-(OH)2D3 to reach a plateau at 50 nM.
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.