This study was conducted to see if slow test presentations of 1 Hz was detected by the chromatic system and higher rates of flicker of 25 Hz, 33 Hz and 40 Hz were detected by the pure flicker system at lower and higher background luminances. Spectral sensitivity measurements were carried out using a 1.2 degree test spot presented at a rate of 1 Hz, 25 Hz, 33 Hz and 40 Hz on a white background. The background luminance used were 100 td, 250 td, 500 td, 750 td, 1000 td, 2500 td and 4000 td. The study showed that the detection of a 1 Hz test is possible by 2 mechanisms, the chromatic system at high background luminance and the achromatic and chromatic systems at low background luminance. In the case 25 Hz, it is not entirely detected by the 'pure flicker system' and the transient achromatic system might contribute in its detection. Flicker rates of 33 Hz and higher are detected by the pure flicker system.
Kajian ini dilakukan untuk melihat sama ada presentasi ujian secara perlahan iaitu 1 Hz dikesan oleh sistem kromatik dan ketipan pada kadar yang tinggi, iaitu 25 Hz, 33 Hz dan 40 Hz dikesan oleh sistem ketipan yang tutin pada luminans latar belakang rendah dan tinggi. Pengukuran sensitiviti spektral telah dijalankan dengan menggunakan satu cahaya ujian bulat berukuran 1.2 darjah yang dipersembahkan pada kadar 1 Hz, 25 Hz, 33 Hz dan 40 Hz pada latar belakang putih. Luminans latar belakang yang telah digunakan adalah 100 td, 250 td, 500 td, 750 td, 1000 td dan 4000 td. Kajian ini menunjukkan yang pengesanan ujian 1 Hz adalah melalui 2 mekanisma, mungkin sistem kromatik pada luminans latar belakang yang tinggi dan sistem akromatik dan kromatik pada luminans latar belakang yang rendah. Bagi 25 Hz pula, ia tidak secara keseluruhannya dikesan oleh sistem kelipan yang tutin dan mungkin sistem akromatik transien yang terlibat dalam pengesanannya. kadar ketipan 33 Hz dan lebih darinya adalah dikesan oleh sistem ketipan yang tulin.
Loranthus parasiticus Merr (L. parasiticus) is a member of Loranthaceae family and is an important medicinal plant with a long history of Chinese traditional use. L. parasiticus, also known as Sang Ji Sheng (in Chinese), benalu teh (in Malay) and baso-kisei (in Japanese), is a semiparasitic plant, which is mostly distributed in the southern and southwestern regions of China. This review aims to provide a comprehensive overview of the ethnomedicinal use, phytochemistry and pharmacological activity of L. parasiticus and to highlight the needs for further investigation and greater global development of the plant's medicinal properties. To date, pharmacological studies have demonstrated significant biological activities, which support the traditional use of the plant as a neuroprotective, tranquilizing, anticancer, immunomodulatory, antiviral, diuretic and hypotensive agent. In addition, studies have identified antioxidative, antimutagenic, antiviral, antihepatotoxic and antinephrotoxic activity. The key bioactive constituents in L. parasiticus include coriaria lactone comprised of sesquiterpene lactones: coriamyrtin, tutin, corianin, and coriatin. In addition, two proanthocyanidins, namely, AC trimer and (+)-catechin, have been recently discovered as novel to L. parasiticus. L. parasiticus usefulness as a medicinal plant with current widespread traditional use warrants further research, clinical trials and product development to fully exploit its medicinal value.