There are some limitations in the database that need to be mentioned.
We then evaluated trends in usage by region and certain specific countries, explored limitations in the database, and made suggestions for improving methods for data collection and reporting.
The search strategy itself could miss studies that others might consider to be social science research, because of limitations in the database abstraction process.
In our final risk assessment, we did not account for the origin of each specific importation because of limitations in the database, likely caused by a complicated system of exportation and reimportation.
Owing to limitations in the database we could not control for disease specifics in each population such as location/size of occlusion, collateral reperfusion, blood glucose level and admission National Institutes of Health Stroke Scale (NIHSS) score.
It has been reported that ILC more often involves the meninges and spinal fluid [ 13, 36- 38] but we were unable to address this issue directly because of limitations in the database.
Although identification through BOLD and the NCBI-GenBank shows 99 100% matching with Antilope cervicapra sequences, the low number of sequence availability reflects a serious limitation in the database-based identity.
Although our lack of success in finding homologous sequences may be due to limitations in the sequence databases of these lower photosynthetic organisms, it seems equally likely that the final pathway components simply did not exist until land plants evolved.
Electronic search was performed in January 2016 with no time and language limitations in the following databases: The Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Scopus, PubMed, Web of Science, Google Scholar Beta, Trip, OpenGrey (to identify the grey literature) and PQDT OPEN from proQuest (to identify dissertations and theses).
As part of our findings, we identified several limitations in the service databases which can be addressed to improve the validity of future studies.
