Advanced analytical techniques for the extraction and characterization of plant-derived essential oils by gas chromatography with mass spectrometry.

In recent years, essential oils have received a growing interest because of the positive health effects of their novel characteristics such as antibacterial, antifungal, and antioxidant activities. For the extraction of plant-derived essential oils, there is the need of advanced analytical techniques and innovative methodologies. An exhaustive study of hydrodistillation, supercritical fluid extraction, ultrasound- and microwave-assisted extraction, solid-phase microextraction, pressurized liquid extraction, pressurized hot water extraction, liquid-liquid extraction, liquid-phase microextraction, matrix solid-phase dispersion, and gas chromatography (one- and two-dimensional) hyphenated with mass spectrometry for the extraction through various plant species and analysis of essential oils has been provided in this review. Essential oils are composed of mainly terpenes and terpenoids with low-molecular-weight aromatic and aliphatic constituents that are particularly important for public health.

COVID-19 Fear Among Pakistanis: Psychometric Evaluation of the Fear of COVID-19 Scale Using Item Response Theory and Confirmatory Factor Analysis.

The Fear of COVID-19 Scale (FCV-19S) assesses the fear of the novel coronavirus disease 2019 (COVID-19) and has been translated and validated into over 20 languages. The present study conducted confirmatory factor analysis (CFA) and item response theory (IRT) analyses on the FCV-19S among a sample of 937 Pakistani adults (mean [SD] age of 25.83 [11.80] years; 537 [57.3%] females). The CFA and IRT confirmed the unidimensionality of the FCV-19S. The Likert-type scale used in the FCV-19S was supported by the proper threshold orderings. Additionally, no DIF contrast had an absolute value larger than 0.5 regarding the participants' characteristics of gender, age, living status, and education in the IRT findings. The FCV-19S was found to be valid and reliable with strong psychometric properties among the Pakistani adult population.