We detail observations of gamma rays produced by interactions of cosmic rays and solar-energetic particles on the Earth’s atmosphere. The Solar Maximum Mission (SMM) spectrometer accumulated the quiescent atmospheric spectrum over its full 9-year lifetime and our analysis revealed 20 resolved line features. We compare this spectrum with one collected on October 20, 1989, when SMM observed gamma...

We propose that a nearby gamma-ray burst (GRB) or GRB-like (old, single and short-lived) pulsar/microquasar about 105−6 years ago may be responsible for the excesses of cosmic-ray positrons and electrons recently observed by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. We can reproduce the smooth Fermi/HESS spectra as well as the spiky ATIC/PPB-BETS spectra. The spectra have a sharp c...

Abstract Some of the microorganisms in soil play important roles plant performance by improving mineral nutrition. Zinc (Zn) is an essential micronutrient that has various functions and only obtained intake foods. Rice a staple food for Indonesian people. Increasing Zn concentration rice through fertilization gamma irradiated inoculants consortium effective way to accumulate grains. The objecti...

The Rad51 protein, a eukaryotic homologue of Escherichia coli RecA, plays a central role in both mitotic and meiotic homologous DNA recombination (HR) in Saccharomyces cerevisiae and is essential for the proliferation of vertebrate cells. Five vertebrate genes, RAD51B, -C, and -D and XRCC2 and -3, are implicated in HR on the basis of their sequence similarity to Rad51 (Rad51 paralogs). We gener...

background: quantification of radiation-induced apoptosis in peripheral blood lymphocytes (pbls) has been proposed as a possible screening test for cancer-prone individuals and also for the prediction of normal tissue responses after radiotherapy. materials and methods: the neutral version of the comet assay (single-cell gel electrophoresis) was used 24, 48, 72 hours after irradiation with 8 gy...

background: radio-adaptive response and bystander effects are known phenomena occurring in cells following exposure to ionizing radiation (ir). in this study we examined possible radio-adaptation of lymphocytes following bystander effects induced by cho-k1 cells. materials and methods: whole blood and cho-k1 cells were cultured in rpmi-1640 complete medium. cells were separately irradiated with...

background: the characteristics of secondary neutrons in a high energy radiation therapy room were studied using the mcnpx monte carlo (mc) code. materials and methods: two mc models including a model with full description of head components and a simplified model used in previous studies were implemented for mc simulations. results: results showed 4-53% difference between full and with the sim...

background: radioprotective effect of famotidine was previously shown on radiation induced micronuclei and chromosomal aberrations in human peripheral lymphocytes and mouse bone marrow cells however, its radioprotective property has never been studied in mouse spermatogenesis. it was also shown that vitamin c as an antioxidant also exert its radioprotective effect on many biological systems, bu...

3-Amino-1,2,4-benzotriazine-1,4-dioxide (SR 4233) is a bioreductive anticancer drug which has a high selective toxicity to hypoxic cells. We have characterized the DNA and chromosome damage in wild-type Chinese hamster ovary (CHO) cells and mutant XR-1 cells after exposure to SR 4233 under hypoxia and compared it to the damage produced by ionizing radiation (gamma-rays). Using the technique of ...