The phrase 'demonstrated a high level' is correct and usable in written English.
You can use this phrase when you want to indicate that someone has exhibited a high level of accomplishment in a particular area. For example, "Sarah demonstrated a high level of proficiency in her math class and achieved top marks in her final exams."
He has neutralised controversies and in giving up his political status he has demonstrated a high level of political skill.
"During its long tenure as the company's outside auditors, Arthur Andersen has provided many years of quality service and has demonstrated a high level of professionalism," FedEx said.
This evaluation demonstrated a high level of technical proficiency.
His assignment was awarded a B grade as it fulfilled the task requirements and demonstrated a high level of creativity.
Cytotoxicity evaluation assay demonstrated a high level of safety profile of the synthesized sulfonium salts against normal cell line.
Analysis of the tissue expression patterns of xPKD1 demonstrated a high level of expression in the kidney.
The enthusiastic agent had a smiling face, frequently nodded its head, demonstrated a high level of animated gestures, and spoke in an enthusiastic voice.
On the other side hot-box measures demonstrated a high level of thermal resistance of the system reaching U-values around 0,20 W m-2 K-1.
The encapsulated cells demonstrated a high level of cell survival (90% for co-culture condition, day 7) and spreading throughout the hydrogel matrix in both culture conditions.
Currently, we are carrying out studies using the SIR method, which has demonstrated a high level of precision in clinical practice and provides us with a meaningful LIC value in μmol Fe/g to include in clinical reports.
We have therefore demonstrated a high level theoretical link between brain oscillations [25], differential excitability in brain networks (e.g. [26]) and abnormal rhythm generation, which are crucial concepts for epilepsy.
