"markedly expand" is a correct phrase and can be used in written English.
It means to greatly or significantly increase or grow in a noticeable way. Example: "The company's profits have markedly expanded in the past year, thanks to their new marketing strategies."
If the federal government wanted to rectify this problem, it could markedly expand the availability of public health loans to medical students to defray the enormous cost of medical-school tuition.
Because NICOM is totally noninvasive, it can markedly expand the number of patients in which accurate continuous CO monitoring is possible.
Last, metadata sets will emerge that will markedly expand the ability to validate and to model transcriptional networks of biological and clinical significance.
Scaling up the continuum of care Scaling up the continuum of care with packaged interventions could markedly expand universal coverage of essential care for mothers and children across their life cycles in an integrated primary-health-care system.
Brazil is the recent pacesetter, markedly expanding public education and systematically attacking remaining pockets of poverty through targeted transfer programmes.
And while not everyone agrees on the aesthetics, or the architecture, some things about Mr. Piano's contribution are beyond debate: The new wing gives the venerable museum room to breathe, markedly expanding the number of works on display.
The space shuttle signaled a new era in space and markedly expanded the scope of human activity there.
Contrast-enhanced abdominal computed tomography demonstrated a large heterogeneous mass, 5 cm in length, with focal enhancement that markedly expanded the extraluminal site of the IVC and infrahepatic portion, which anteriorly displaced the bowel loops and compressed the IVC and head of the pancreas (Fig. 1).
Donald Trump is moving into a White House that has seen presidential powers markedly expanded by its previous two occupants.
As anyone who saw the band on its early run last year would note, the show now is markedly expanded with more musicians and singers on stage, larger lighting rigs, and even more instruments for all four members to play with during a set.
In lateral and medial view the distal condyles are markedly expanded cranio-caudally.
