Emanuele Calabrò

Determining optimum tilt angles of photovoltaic panels at typical north-tropical latitudes

An application of renewable energy technology is the installation of photovoltaic systems that generate power without emitting pollutants and requiring no fuel. Solar radiation varies with geographic latitude, season, and time of day due to the various sun positions in the sky. Hence, the problem of designing the optimal tilt angle and the orientation of a solar panel arises for maximizing solar radiation collection at a fixed latitude. An approach of employing sky radiance models for determining optimal tilt angle values of solar collectors with respect to a set of geographic latitudes was conducted by using a data archive of the daily global solar radiation collected by the Italian Institute of ENEA. The results provided a set of tilt angles for winter months that enables a solar panel to absorb the maximum amount of global solar radiation and another set of smaller tilt angle values for summer months, as well. The great difference between these two sets suggested to us to plan semifixed solar panels wh...

FTIR spectroscopy studies on the bioprotective effectiveness of trehalose on human hemoglobin aqueous solutions under 50 Hz electromagnetic field exposure.

The effects of extremely low frequency electromagnetic field on the protein structure of hemoglobin were investigated by means of Fourier transform infrared spectroscopy. Three samples of different hemoglobin aqueous solutions (also in the presence of sucrose and trehalose) were exposed to a 50 Hz electromagnetic field at 1 mT, and FTIR measurements were performed after 3 h of exposure. Quantitative spectral analysis revealed an evident decrease in amide A band intensity for hemoglobin in bidistilled water and sucrose aqueous solutions, but not for hemoglobin in trehalose aqueous solution. In addition a low relative increase of β-sheet in amide I region was detected for hemoglobin in both bidistilled water and sucrose aqueous solutions, whereas no appreciable changes were evidenced in the infrared spectra of hemoglobin in trehalose aqueous solutions. These results led us to conclude that a 50 Hz electromagnetic field can affect the N-H plane bending and C-N stretching vibrations of peptide linkages, suggesting compensatory mechanisms by means of environmental biochemical agents, such as evidenced by a protective effect of trehalose toward a low-frequency electromagnetic field.

Modulation of heat shock protein response in SH-SY5Y by mobile phone microwaves.

AIM To investigate putative biological damage caused by GSM mobile phone frequencies by assessing electromagnetic fields during mobile phone working. METHODS Neuron-like cells, obtained by retinoic-acid-induced differentiation of human neuroblastoma SH-SY5Y cells, were exposed for 2 h and 4 h to microwaves at 1800 MHz frequency bands. RESULTS Cell stress response was evaluated by MTT assay as well as changes in the heat shock protein expression (Hsp20, Hsp27 and Hsp70) and caspase-3 activity levels, as biomarkers of apoptotic pathway. Under our experimental conditions, neither cell viability nor Hsp27 expression nor caspase-3 activity was significantly changed. Interestingly, a significant decrease in Hsp20 expression was observed at both times of exposure, whereas Hsp70 levels were significantly increased only after 4 h exposure. CONCLUSION The modulation of the expression of Hsps in neuronal cells can be an early response to radiofrequency microwaves.

Unfolding and Aggregation of Myoglobin Can Be Induced by Three Hours’ Exposure to Mobile Phone Microwaves: A FTIR Spectroscopy Study

ABSTRACT The effects of 3 hours’ exposure to mobile phone microwaves at 1765 MHz at the power density around 800 mW/m2 on the secondary structure of myoglobin in D2O solution were investigated by Fourier transform infrared spectroscopy. A significant shift to lower frequencies of the amide I vibration was observed after exposure. Furthermore, a significant increasing of the β-sheet components with respect to the α-helix content after exposure was highlighted after applying Fourier self-deconvolution analysis in the amide I region. These results led to the conclusion that mobile phone microwaves induce unfolding of myoglobin and formation of aggregates.

Effects of low intensity static magnetic field on FTIR spectra and ROS production in SH-SY5Y neuronal-like cells

Biological effects of man-made electromagnetic fields (EMFs) have been studied so far by experimental approaches exposing animals and cell cultures to EMFs. However, the evidence for cell toxicity induced by static magnetic field (SMF) is still uncertain. We investigated the effects produced by the exposure of human SH-SY5Y neuronal-like cells to a uniform magnetic field at intensities of 2.2 mT, which is less than the recommended public exposure limits set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). A decrease of membrane mitochondrial potential up to 30% was measured after 24 h of exposure to SMF in SH-SY5Y cells, and this effect was associated with reactive oxygen species production increase. Fourier transform infrared spectroscopy (FTIR) analysis showed that exposure to a static magnetic intensity around 2.2 mT changed the secondary structure of cellular proteins and lipid components. The vibration bands relative to the methylene group increased significantly after 4 h of exposure, whereas further exposure up to 24 h produced evident shifts of amide I and II modes and a relative increase in β-sheet contents with respect to α-helix components. Our study demonstrated that a moderate SMF causes alteration in cell homeostasis, as indicated by FTIR spectroscopy observations of changes in protein structures that are part of cell response to magnetic field exposure.

Studying the Electromagnetic-Induced Changes of the Secondary Structure of Bovine Serum Albumin and the Bioprotective Effectiveness of Trehalose by Fourier Transform Infrared Spectroscopy

Samples of bovine serum albumin in H(2)O and D(2)O solutions, in the absence or presence of trehalose, were exposed separately to a static magnetic field at 200 mT and to a 50 Hz electromagnetic field at 1.8 mT, studying the relative effects on the secondary structure of the protein by means of Fourier transform infrared spectroscopy. The spectra acquired in the mid-infrared region after 2 and 4 h of exposures to the static magnetic field showed a decrease in amide A and amide I band intensities for the protein in bidistilled aqueous solutions that was also evidenced after exposures to a 50 Hz electromagnetic field. These results led us to conclude that electromagnetic fields of low intensities can affect the C═O and C-N stretching vibrations and N-H plane bending of peptide linkages. Furthermore, mid-infrared spectra of bovine serum albumin in trehalose aqueous solutions were not significantly modified after the exposures, confirming the hypothesis of the possible bioprotective effectiveness of trehalose against electromagnetic fields.

Electromagnetic Fields Effects on the Secondary Structure of Lysozyme and Bioprotective Effectiveness of Trehalose

FTIR spectroscopy was used to investigate the effects of extremely low frequency (50 Hz) electromagnetic field and of microwaves at 900 MHz on the secondary structure of a typical protein, the lysozyme, evaluating the bioprotective effectiveness of trehalose. Lysozyme in D2O solution (60 mg/ml) was exposed to 50 Hz frequency electromagnetic field at 180 μT. The FTIR spectra indicated an increase of CH2 group at 1921 and 1853 cm−1 after 3 h of exposure. Such effect was not observed after the addition of trehalose (150 mg/mL) at the same exposure conditions. Lysozyme dissolved in D2O at the concentration of 100 mg/mL was exposed up to 4 h to 900 MHz mobile phone microwaves at 25 mA/m. A significant increase in intensity of the amide I vibration band in the secondary structure of the protein was observed after 4 h exposure to microwaves. This effect was inhibited by the presence of trehalose at the concentration of 150 mg/mL. Fourier self-deconvolution spectral analysis of lysozyme in D2O solution after exposure to microwaves revealed an increase in intensity of the conformational components of amide I mode, particularly of β-sheet and turn that can be attributed to disorder and unfolding processes of the protein.

Demicellization of Polyethylene Oxide in Water Solution under Static Magnetic Field Exposure Studied by FTIR Spectroscopy

FTIR spectroscopy was used to investigate the alterations of the vibration bands in the mid-infrared region of Polyethylene oxide in aqueous solution at 25 mg/mL concentration under exposure up to 4 h to a static magnetic field at 200 mT. FTIR spectroscopic analysis of PEO solution in the range 3500–1000 cm−1 evidenced the stretching vibrations of ether band, C–H symmetric-antisymmetric and bending vibrations of methylene groups, and the C–O–C stretching band. A significant decrease in intensity of symmetric and asymmetric stretching CH2 vibration bands occurred after 2 h and 4 h of exposure, followed by a significant decrease in intensity of scissoring bending in plane CH2 vibration around 1465 cm−1. Finally, the C–O–C stretching band around 1080 cm−1 increased in intensity after 4 h of exposure. This result can be attributed to the increase of formation of the intermolecular hydrogen bonding that occurred in PEO aqueous solution after SMF exposure, due to the reorientation of PEO chain after exposure to SMF. In this scenario, the observed decrease in intensity of CH2 vibration bands can be understood as well considering that the reorientation of PEO chain under the applied SMF induces PEO demicellization.

50 Hz electromagnetic field produced changes in FTIR spectroscopy associated with mitochondrial transmembrane potential reduction in neuronal-like SH-SY5Y cells.

SH-SY5Y neuroblastoma cells were used as an experimental model to study the effects of 50 Hz electromagnetic field, in the range from 50 µT to 1.4 mT. Fourier transform infrared spectroscopy analysis evidenced a reduction in intensity of the amide A band and a slight increase of vibration bands at 2921 cm−1 and 2853 cm−1 corresponding to methylene groups. A further increase of the magnetic field intensity of exposure up to 0.8 mT and 1.4 mT produced a clear increase in intensity of CH2 vibration bands. Moreover, it has been observed some alterations in the amide I region, such as a shifted peak of the amide I band to a smaller wavenumber, probably due to protein conformational changes. These results suggested that exposure to extremely low electromagnetic fields influenced lipid components of cellular membrane and the N–H in-plane bending and C–N stretching vibrations of peptide linkages, modifying the secondary structures of α-helix and β-sheet contents and producing unfolding process in cell membrane proteins. The observed changes after exposure to 50 Hz electromagnetic field higher than 0.8 mT were associated with a significant reduction of cell viability and reduced mitochondrial transmembrane potential.

Parallel β-sheet vibration band increases with proteins dipole moment under exposure to 1765 MHz microwaves

Effects of exposure of 4 h to mobile phones microwaves at 1765 MHz at a power density around 940 mW/m(2) on four typical proteins (hemoglobin in H2 O solution, and myoglobin, bovine serum albumin, and lysozyme in D2 O solution) were studied by means of Fourier Transform Infrared spectroscopy and Fourier self-deconvolution analysis. Increase in intensity of parallel β-sheet component around 1635 cm(-1) was observed after exposure of hemoglobin, myoglobin, and bovine serum albumin, showing that a mechanism of unfolding occurred after exposure, whereas no appreciable change in the amide I region occurred after lysozyme exposure. In addition, a relationship between protein dipole moment and protein unfolding rate was demonstrated with a correlation coefficient r = 0.973 and 95% confidence interval.