Magnetite nanoparticles for biosensor model based on bacteria fluorescence

Fluorescence emission of pyoverdine – the siderophore synthesized by iron scavenger bacteria - was studied using in vitro cultures of Pseudomonas aeruginosa with the aim to design a biosensor system for liquid sample iron loading. Diluted suspensions of colloidal magnetite nanoparticles were supplied in the culture medium (10 microl/l and 100 microl/l) to simulate magnetic loading with iron oxides of either environmental waters or human body fluids. The electromagnetic exposure to radiofrequency waves of bacterial samples grown in the presence of magnetic nanoparticles was also carried out. Cell density diminution but fluorescence stimulation following 10 microl/l ferrofluid addition and simultaneous exposure to radiofrequency waves was evidenced. The inhibitory influence of 100 microl/l ferrofluid combined with RF exposure was evidenced by fluorescence data. Mathematical model was proposed to approach quantitatively the dynamics of cell density and fluorescence emission in relation with the consumption of magnetite nanoparticle supplied medium. The biosensor scheme was shaped based on the response to iron loading of bacterial sample fluorescence

Occupational Exposure to Power Frequency Fields in Some Electrical Transformation Stations in Romania

The aim of this study is to investigate the levels of electric and magnetic power frequency fields at 8 electrical transformation stations in the North-East counties of Romania and to check their compliance with standards Spot measurements were carried out on both electric and magnetic fields under overhead conductors of 110-, 220- and 380-kV installations. The magnetic field levels were several orders of magnitude below the reference level for occupational exposure set by ICNIRP (International Commission on Non-Ionizing Radiation) or by Romanian regulations. In contrast, the electric field levels were about the same order of magnitude as the reference levels. In 2 electrical stations the reference level of 10 kV/m was exceeded at specific locations within the outdoor installations area. However, the additional reference level for short-time exposure included in Romanian regulations, 30 kV/m, was not exceeded

ULTRA HIGH FREQUENCY WAVES EFFECT UPON ASSIMILATORY PIGMENTS IN OAK SEEDLINGS

The influenc e of ultra high fre que ncy ra diation in forestry arbor se e dlings wa s studie d by spec tra l me thod. Chlorophy ll pigm e nt c onte nts, ve ry im porta nt for photosy nthe sis phe nome na , we re found to be dim inishe d in pe dunc ula te oa k see dlings a fter da ily e xposure tim es of: 1;2; 3; 4; 6 a nd 8 hours, a t ultra high frequency waves with 400 M H z fre que ncy a nd 1 mW /cm 2 powe r de nsity. N on-therma l effect seem s to underline th putative m olecular and biochemica l modifications that are suppose d to be induced in the vegetale cell by electromagnetic daily stres

A preliminary study on ultra high frequency electromagnetic fields effect on black locust chlorophylls

Chlorophylls were quantitatively studied in the leaves of black locust (Robinia pseudoacacia L.) seedlings exposed to electromagnetic fields of high frequency. Exposure system was designed and built up to make possible simultaneous exposure of seedling lots (3 months old) to low power density electromagnetic fields corresponding to a frequency of 400 MHz. After three weeks of daily exposures (1, 2, 3 and 8 hours), chlorophyll levels were measured using adequate spectral device. Statistical analysis of experimental results was performed by means of t-test to identify significant modifications induced by electromagnetic treatment in exposed samples in comparison to the control. Chlorophyll-a as well as chlorophyll-b level was found to decrease except the exposure time of two hours, where a considerable enhancement was noticed. It was revealed that the ratio of the two main types of chlorophyll was decreasing logarithmically to the increase of daily exposure time