The phrase "a sample of center" is not correct in standard written English.
It may be intended to refer to a sample taken from a central point or location, but the wording is unclear and lacks proper context.
Example: "We collected a sample of center from the research site to analyze the core characteristics of the area."
Alternatives: "a sample from the center" or "a central sample".
We examined the short-term comparative safety of bolus versus maintenance dosing in a sample of center-based hemodialysis patients and found that bolus dosing was associated with increased infection risk, particularly in the subgroup of patients with a catheter.
The objective of this study was to evaluate the proposed International Statistical Classification of Diseases and Related Health Problems (10th revision) (ICD-10) criteria in a sample of cancer patients from a medical center and a regional teaching hospital in northern Taiwan.
We chose cross-sectional descriptive study during February 2014 using a sample of 24 health centers, which represent 20%% of total health centers that perform VIA screening in the region (Additional files 1 and 2).
To draw a random sample of centers, a multi-step procedure was used in which more than 25,000 physicians were contacted (Department of Medical Informatics, Biometry and Epidemiology, University of Bochum).
The new study is based on a sample of child care centers in Atlanta, Boston, Detroit, Phoenix and Seattle.
A cross-sectional study was carried out in a sample of primary care centers.
An interview-based study of key stakeholders from a sample of US cancer centers.
A cross-sectional study was carried out in a sample of primary care centers in Spain between April 2006 and December 2006.
Consistent with previous work [ 18, 19], we found evidence of an association between bolus dosing and infection outcomes and no association between bolus dosing and cardiovascular outcomes, in a sample of patients receiving center-based hemodialysis.
The 6-month-long intervention took place in a sample of 32 licensed centers (16 intervention, 16 control) serving racially and ethnically diverse children under the age of 2 years in the greater Boston, Massachusetts (MA) area [ 33].
These two centers represented a convenience sample of centers affiliated with the authors.
