The use of smoked illicit drugs has spread dramatically, but few studies use proper devices to expose animals to inhalational abused drugs despite the availability of numerous smoking devices that mimic tobacco exposure in rodents.
Because both scales are commonly used, but few studies use both, translating between scales is important in gaining an overall understanding of the efficacy of alternative treatments, and in developing prognostic models that combine several datasets.
Standard clearance of inulin, including urine collection, remains the 'gold-standard' method for GFR measurement but few studies use this.
There are several structural imaging studies in DS with age in the literature (reviewed in [ 9]) but fewer studies using amyloid positron emission tomography (PET) imaging ligands [ 10].
The search identified several studies considering QOL for individuals with IPF, but fewer studies used a qualitative approach to explore their experiences of the disease.
The regression methods have found fields of application primarily in chemometrics, econometrics and social sciences e.g. [ 8, 9], but there have been only very few studies using PLSR and PCR concerned with their suitability for prediction of breeding values using large-scale molecular data, e.g. [ 10, 11].
Outside of arthropods, few studies using invertebrates explicitly test for convergence and parallelism (but see gastropods: [ 25, 26]; bivalves: [ 27]).
However, in recent years, a few studies using a combination of instrumental data and simple climate models have arrived at lower estimates.
Few studies using organic solvents for terpenes extraction have been published.
To date, there have been few studies using newer radiopharmaceuticals other than 18F-FDG for evaluation of sarcoidosis.
