thermal rearrangement of 7,7-dichloro-[a,c]-dibenzo-[4,1,0]-bicycloheptane (1) to 5,6-dichloro-5hdibenzo-[a,c]-cycloheptene (2) was studied in the solid phase and in solvents with different polarities. thefirst-order constants at various temperatures for the rearrangement process were evaluated from theabsorption time data. the activation parameters for this rearrangement were obtained from the...

introduction: photon attenuation in tissues is the primary physical degrading factor limiting both visual qualitative interpretation and quantitative analysis capabilities of reconstructed single photon emission computed tomography (spect) images. the aim of present study was to investigate the effect of attenuation correction on the detection of activation foci following statistical analysis w...

cellulose wastes of a wood and paper factory were used to produce activated carbon. several chemical agents under various conditions were used for production of activated carbon and hence their adsorption properties have been evaluated. in addition the effect of process parameters such as raw material, chemical agent concentration, impregnation ratio, carbonization temperature, carbonization ti...

objective(s): so far, extensive research has been conducted on the preparation and characterization of nano ceramics based on ca-si by sol- gel method and bioactivity was evaluated, but, a few researches have paid attention to the preparation of materials by mechanical activation (ma). the aim of this study was the preparation of akermanite nano powder by mechanical activation method and bioact...

fertilization is triggered by changes in intracellular calcium concentration. in mammals, these transients in ooplasmic calcium concentration take the form of repetitive spikes, so called calcium oscillations (ca2+-oscillations). these oscillations are important for relieve of meiotic arrest and to induce all the other events of oocyte activation. although a surface mediated way of oocyte activ...

introduction there is a growing interest in determining the concentration of various elements in food spices. in the present study, the instrumental neutron activation analysis (inaa) was employed to measure the trace elements in 11 commonly food spices consumed in tehran, iran. materials and methods the levels of k, mn, na, cl, v, br, al, and as were determined and their effects on human healt...

background: focal segmental glomerulosclerosis (fsgs) is a type of nephrotic syndrome which is diagnosed by renal biopsy. degree of the proteinuria, renal dysfunction, histologic findings and the response to therapy are some factors used for evaluating the prognosis of fsgs. objectives: in the present study, we attempted to discover some protein candidates for disease prognosis related to glome...

background: recurrent spontaneous abortion (rsa) and in vitro fertilization (ivf) failure with unknown causes are the controversial issues that are probably related to the immune system. objective: to compare circulating nk cells expressing activation and inhibition surface markers between patients with rsa and ivf failure with those of healthy multiparous and successful ivf control women, resp...

in this study, the adsorption of hexavalent chromium and zinc ions from the solution is investigated by raw red mud and mechanical-chemical activated red mud along with the possibility of selective reclamation of these ions from the solution. the mechanical-chemical activation of red mud was done by employing high-energy milling and subsequent acid treatment with hno3. raw red mud (rrm) and mec...

cotton fibres were subjected to cleaning process and then characterized for maturity. decrystallisation and swelling processes with caustic soda, ethanol, propan-2-ol and trichloroethene on the native fibres were carried out. the effects of these on the strength and moisture regain were investigated. the activation energies of the dyeings were also analysed with durazol scarlet red 4 bas. the r...