soil samples were collected from seven sites in and around the metropolitan area of mexicocity. the locations were chosen as possible sources of fugitive dusts which contribute to suspended particulate matter in the atmosphere of mexico city. x-ray fluorescence (xrf) was used to determine the concentrations of several major elements (si, k, ca, ti, mn, and fe), as well as of other trace element...

the radiobiological effects of high atomic number and energy (hze particles) ion beams are of interest for radioprotection in space and tumor radiotherapy. space radiation mainly consists of heavy charged particles from protons to iron ions, which is distinct from common terrestrial forms of radiation. hze particles pose a significant cancer risk to astronauts on prolonged space missions. with ...

introduction use of hadron therapy as an advanced radiotherapy technique is increasing. in this method, secondary particles are produced through primary beam interactions with the beam-transport system and the patient’s body. in this study, monte carlo simulations were employed to determine the dose of produced secondary particles, particularly neutrons during treatment. materials and methods i...

zinc and iron nano-oxides (100 ppb) were promoted the hypericin and hyperforin production in hypericum perforatum cell suspension culture. high performance liquid chromatography method was used for detectection and identification of hypericin and hyperforin in h. perfuratum cell suspension cultures elicited with different concentrations of zinc and iron nano-oxide (0, 50, 100 and 150 ppb) after...

using titanium dioxide nano-silver packaging, which is antibacterial and resistance to the diffusion of gases such as oxygen, is increasing in food industry. therefore, we compared the effect of titanium dioxide-based nano-silver packaging and conventional polyethylene packaging on the fungal flora of consuming bread in order to increase the shelf-life storage of consuming bread. one hundred fo...

Are black holes elementary particles? Are they fermions or bosons? We investigate the remarkable possibility that quantum black holes are the smallest and heaviest elementary particles. We are able to construct various fundamental quantum black holes: the spin-0, spin-1/2, spin-1, and the Planckcharge cases, using the results in general relativity. Quantum black holes in the neighborhood of the...

Planned Lunar missions have resulted in renewed attention to problems attributable to fine particulates. While the difficulties experienced during the sequence of Apollo missions did not prove critical in all cases, the comparatively long duration of impending missions may present a different situation. This situation creates the need for a spectrum of particulate sensing technologies. From a f...

Recent observations show that some or possibly all long-duration gamma-ray bursts (GRBs) arise from the core collapse of massive stars. In this case, the GRB environments are believed to be preburst stellar winds. We here study prompt neutrino emission from reverse shocks as a result of the interaction of relativistic fireballs with their surrounding wind matter. We find that for reasonable par...

aza heterocyclic compounds are major interest for organic chemists because of their mainly pharmacological activities and clinical applications such as antianxiety, antitumor, anticonvulsant, cardiotonic and vasorelaxant. this contribution describes an electrochemical approach for the preparation of nanosized particles of phthalazine in high yields and very short reaction time. the method is ba...