Effects of morphogenetic and diurnal variability on the hypericin content in St. John’s Wort (Hypericum perforatum L.)

This research was conducted to investigate effects of morphogenetic and diurnal variability on the hypericin content of St. John’s Wort (Hypericum perforatum L.) populations originating from Turkey formaximum utilization of the active substance in plants. During 2002 and 2003, field trials were conducted at Uludag University, Faculty of Agriculture, Department of Field Crops, Bursa, Turkey. Samples of bud,flower and capsule of H. perforatum L. populations were collected in the second year of cultivation (2003). Factorial arrangements of three H. perforatum L. populations (Bursa, Edirne, Izmir), three part ofplant (bud, flower, capsule) and six collection h (8:00, 10:00 a.m; 12:00 (noon), 2:00, 4:00, 6:00 p.m) were evaluated in a completely randomized block design with three replications. Hypericin content (%) in parts of H. perforatum L. populations was determined according to DAC (1986). Consequently, the content of hypericin in the examined populations varied from 0.260% in Bursa to 0.283% in Izmir.Evaluating plant parts revealed that the hypericin content both in floral parts (0.309%) and buds (0.308%) were higher than capsule tissues (0.208%) for all populations. When collection hours wereexamined for the hypericin content of plants, the highest content was recorded at 10:00 a.m (0.279%) and the lowest value at 4:00 p.m (0.272%) and 6:00 p.m (0.272%). As a result, this study showed that the highest hypericin ratio was determined in flowers and buds generally collected between 8:00 and 10:00 a.m within a day for examined Hypericum populations

Phototransferred thermoluminescence from alpha-Al2O3:C using blue light emitting diodes.

Phototransferred thermoluminescence (PTTL) from alpha-Al2O3:C single crystals was studied using a blue light emitting diode (LED) for phototransfer of charges from deep traps to the main dosimetry trap. The dose response was found to be linear in the region from similar to 5 mGy to similar to 5 Gy. It was observed that the corresponding deep traps were located near 500 degrees C and heating to temperatures > 600 degrees C removes the PTTL effect induced by the light from the blue LED. The thermal activation energy of the source traps involved in the PTTL production was calculated as 3.23 eV

OSL from beo ceramics: new observations from an old material.

In BeO ceramics, exposed to ionizing radiation, an intense OSL signal was observed. The properties of the signal and its behavior under various experimental conditions were investigated. It was found that the OSL signal is a composite signal and exhibits strong thermal quenching. The quenching energy was estimated as similar to 0.5 eV. The excitation spectrum of the OSL signal was obtained as a broad peak in the region 420-550 nm with maximum around 435 nm. The possible correlation between the OSL signal and the peaks in the TL glow curve was also examined. It was interesting to observe that the highly light sensitive TL peak near 220 degrees C does not contribute to the OSL signal. The OSL signal was found to originate from a trap near 340 degrees C. To check the possibility of using the material for radiation dosimetry the dose response and thermal stability of the OSL signal were also investigated. The dose response was found to be guile linear up to similar to 10 Gy. The thermal activation energy of the OSL trap was determined as similar to 1.7 eV using isothermal annealing and heating rate methods thus proving the suitability for dosimetry

Rotifera and Cladocera fauna of the River Seyhan (the part within borders of Adana city) [Seyhan Nehrinin (Adana i·l Merkezi sinirlari i·çindeki bölümünde) Rotifera ve Cladocera faunasi]

In this study between November 1991 and October 1992, the unexplored Rotifera and Cladocera faunas were investigated both qualitatively and quantitatively in the part within borders of Adana city. The research yielded 17 spp. and 1 subsp. of Rotifera and 9 ssp. of Cladocera

Le séisme de Kocaeli en Turquie : mission de reconnaissance

Compte rendu de la mission de reconnaissanc