PHYTOCHEMISTRY AND ETHNOPHARMACOLOGY OF THE SEA GRASS CYMODOCEACEA FAMILY– A REVIEW

Cymodoceaceae is a family of flowering plants, sometimes known as the manatee-grass family,†the family Cymodoceaceae includes only marine species. The angiosperm phylogeny II system, of 2003 (unchanged from the APG system, of 1998), does recognize Cymodoceaceae and places it in the order Alismatales, in the clade monocots. They are marine hydrophytes that grow and complete their life cycle in a submerged condition, in a saline environment. Like terrestrial plant they obtain their energy from light through photosynthesis thus, they grow only in clear and shallow water, and at the suitable condition, they form beds or meadows. The family includes five genera, totalling 16 species of marine plants occurring in tropical seas and oceans (so-called seagrasses). Cymodoceaceae consist of five genera such as Amphibolis, Cymodocea, Halodule, Syringodium, and Thalassodendron. In this genera Cymodocea rotundata Ehrenb. and Hempr. Ex Asch. Cymodocea serrulata, (R.Br.) Asch. and Magnus, Halodule pinifolia (Miki) Hartog, Halodule uninervis (Forssk.) Asch and Syringodium isoetifolium (Asch.) are the species mostly adopted in Indian coastal region. These seagrass species have unique nature and wide application to the environment including human being. In this article botanical aspects, phytochemistry and ethnopharmacology of these five seagrass species belong to Cymodoceaceae family will be discussed

Phytochemical screening and in vitro antioxidant activity of the seagrass Cymodocea serrulata

1216-1221The seagrass Cymodocea serrulata was collected from Ramanathapuram coastal region and its antioxidant potential was determined. The ethanol extract showed the highest phenolic content of 284.94 mg/ml gallic acid equivalence and the ethyl acetate extract showed the highest flavonoids content of 40.18 mg/ml quercetin equivalence. The tannin content was higher at 264.71 mg/ml tannic acid equivalence in aqueous extract. The ethanol extract exhibited the highest 2,2 diphenyl-1-picrylhydrazyl (DPPH) and 2,2¢-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity with IC50 values of 44.47 µg and 2.5 µg, respectively. The ferric reducing ability and nitric oxide scavenging activity were efficient in both ethanol and aqueous extracts. The superoxide scavenging activity was high in hexane extract. The comparative antioxidant study of the subsequent extract of C. serrulata showed that the ethanol extract possesses the highest free radical scavenging property compared to other extracts. This may be due to the presence of high phenolic compounds. The study brings out the medicinal value of C. serrulata which can be used as a nutraceutical compound in various food and pharmaceutical industries

A comparison of lower and higher LET heavy ion irradiation effects on silicon NPN rf power transistors

The Silicon NPN rf power transistors were irradiated with 180MeV Au14+ and 150MeV Ag12+ ions in the dose range of 1Mrad to 100Mrad. The SRIM simulation was used to understand the energy loss and range of these ions in the transistor structure. The different electrical parameters such as Gummel characteristics, excess base current (∆IB), dc current gain (hFE), transconductance (gm), displacement damage factor (K) and output characteristics were studied systematically before and after irradiation. These results were compared with lower linear energy transfer (LET) ions such as 50MeV Li3+, 95MeV O7+, 100MeV F8+, 140MeV Si10+ and 175MeV Ni13+ ions in the same dose range. The degradation for 180MeV Au14+ and 150MeV Ag12+ ion irradiated transistors was significantly more when compared to lower LET ions, indicating that the transistors are vulnerable to higher LET ion irradiations. Isochronal annealing study was conducted on the irradiated transistors to analyze the recovery in different electrical parameters. After isochronal annealing, the recovery in hFE and other electrical parameters was around 67 for Ag12+ ion irradiated transistors and 60 for Au14+ ion irradiated transistors

High total dose proton irradiation effects on silicon NPN rf power transistors

The effects of 3 MeV proton irradiation on the I-V characteristics of NPN rf power transistors were studied in the dose range of 100 Krad to 100 Mrad. The different electrical characteristics like Gummel, current gain and output characteristics were systematically studied before and after irradiation. The recovery in the I-V characteristics of irradiated NPN BJTs were studied by isochronal and isothermal annealing methods

The effects of high-energy ion irradiations on the I–V characteristics of silicon NPN transistors

The silicon NPN rf power transistors were irradiated with different linear energy transfer (LET) ions such as 50 MeV Li3+, 80 MeV C6+ and 150 MeV Ag12+ ions in the dose range of 1–100 Mrad. The SRIM simulation was used to understand the energy loss and range of these ions in the transistor structure. The different electrical parameters such as Gummel characteristics, excess base current (ΔIB), DC current gain (hFE), displacement damage factor (K) and output characteristics were systematically studied before and after irradiation. The ion irradiation results were compared with 60Co-gamma irradiation result in the same dose range. A considerable increase in base current (IB) and a decrease in hFE and ICSat were observed after irradiation. The degradation in the electrical parameters was comparably very high for Ag12+ ion-irradiated transistor when compared to other ion-irradiated transistors, whereas the degradation in the electrical parameters for Li3+ and C6+ ion-irradiated transistors was comparable with gamma-irradiated transistor. The isochronal annealing study was conducted on the 100 Mrad irradiated transistors up to 500°C to analyze the recovery in different electrical parameters. The hFE and other electrical parameters of irradiated transistors were almost recovered after 500°C for 50 MeV Li3+, 80 MeV C6+ ion and 60Co-gamma-irradiated transistors, whereas for 150 MeV Ag12+ ion-irradiated transistor, the recovery in electrical characteristics is not complete

Comparison of 1 MeV electron, Co-60 gamma and 1 MeV proton irradiation effects on silicon NPN transistors

ABSTRACTThe total dose effects of 1 MeV electrons on the dc electrical characteristics of silicon NPN transistors are investigated in the dose range from 100 krad to 100 Mrad. The different electrical characteristics such as Gummel characteristics, excess base current (ΔIB), dc current gain (hFE), transconductance (gm), displacement damage factor (K) and output characteristics were studied in situ as a function of total dose. A considerable increase in base current (IB) and a decrease in hFE, gm and ICSat was observed after 1 MeV electron irradiation. The collector–base (C–B) junction capacitance of transistors was measured to estimate the change in the effective carrier concentration. After 1 MeV electron irradiation, a considerable degradation in capacitance was observed. The plot of (1/C2) versus voltage shows that the effective carrier concentration and built-in voltage (Vbi) increase marginally upon 1 MeV electron irradiation. The results of 1 MeV electron irradiation were compared with 1 MeV proton and Co-60 gamma irradiation results in the same dose range. The degradation for 1 MeV electron and Co-60 gamma-irradiated transistors was significantly less when compared to 1 MeV proton-irradiated transistor. The 1 MeV proton, 1 MeV electron and Co-60 gamma-irradiated transistors were subjected to isochronal annealing to analyze the recovery of the electrical parameters