"by twofold" is correct and can be used in written English.
It is typically used to mean "twice as much or twice as many". For example, "The attendance at the lecture was increased by twofold."
First, insulin stimulates hepatic glucose uptake by twofold over the fasting state47.
They are large oligomeric complexes comprising two rings of 7-9 subunits related by twofold symmetry.
The antimicrobial activities of the target compounds were evaluated by twofold serial broth dilution method and poisoned food technique.
Conversely, CBP overexpression augmented the mitochondrial population by twofold (Fig. 6b, c), comparable to that of the NaBt treatment (Fig. 1b).
As it is clearly seen from equation (3), if the rest mass of particles equals zero, their dispersion is described by twofold degenerate cone in energy-momentum space.
Similar to the above findings with cationic lipids, the 59 nucleotide 5′ extension also enhanced PAsp DET -mediated delivery of AsCPAsp DET -mediatedy twofoldelivery
For example, the T5R substitution, designed to create a favorable Coulombic interaction between ONC and a phosphoryl group in RNA, increased ribonucleolytic activity by twofold.
The antibiotic concentrations were lowered by twofold dilutions from 240 to 3.7 μg mL−1.
In fact, the presence of the four HA mutations increased the reactivity with H5 antisera by twofold or more.
After ADR injection, the UACR levels were significantly increased by twofold (p < 0.001) in BALB/C mice.
MCL fatty acid degradation genes fadD, fadL, and fadE were upregulated by twofold, tenfold, and 31-fold respectively.
