Seasonal variation of indoor radon concentration in a desert climate.

Radon is one of the sources that negatively affect dwellings air quality and is ranked as a main cause of lung cancer after cigarette smoking. The indoor radon concentrations usually affected by the conditions of the environment surrounding the dwellings. Seasonal variations can have a significant impact on the indoor radon concentrations. In this article, we studied the seasonal variations of indoor radon concentration in a desert climate, particularly in gulf countries that usually leave the windows and doors closed all over the time. Four hundred dosimeters containing CR-39 detectors were planted for three months to measure the variation in radon concentration between winter and summer seasons. Our measurements showed that a building with a basement revealed a significant variation between radon concentration in winter (44.3 ± 3.1Bqm-3) and in summer (26.1 ± 1.7Bqm-3). Buildings without basements showed that the indoor radon concentration in winter (16.1 ± 1.7Bqm-3) is very much close to that in summer (16.7 ± 1.8Bqm-3). Our results indicated that seasonal variations can significantly affect indoor radon concentration for buildings established with basements. However; in the study region, the average indoor radon concentration as well as the annual effective dose rate are found to be below the action level recommended by ICRP.

Radon concentration and radon effective dose rate in dwellings of some villages in the district of Ajloun, Jordan.

Indoor and soil radon concentrations were measured in the villages of Ayn-Jana, Ishtafena, Samta and Umm-Yanabe' in the district of Ajloun, Jordan. Several factors that are strongly related to the radon concentrations are considered whether in soil such as its type or indoors such as room occupation type, floor level and building materials. In the village of Ayn-Jana, our results showed that the average radon concentration decreases gradually as the floor level increases. The highest concentration was found to be in the ground floor (35.5 ± 5.0 Bqm(-3)) and the lowest was in the second floor (22.9 ± 3.2 Bqm(-3)). Regarding the effect of ventilation rate in the same village, storage rooms revealed the highest concentration (38.8 ± 5.4 Bqm(-3)) while the lowest concentration was in living rooms (33.8 ± 4.4 Bqm(-3)). In the four villages, it was found that the highest radon concentration was in the dwellings made of clay (45.7 ± 6.7 Bqm(-3)) and the lowest was in dwellings made of brick (33.9 ± 6.4 Bqm(-3)). In general, the average indoor radon concentration in these villages was 36.3 ± 2.3 Bqm(-3) and it corresponds to an average effective dose rate of 0.92 ± 0.06 mSvyr(-1). These indoor radon concentrations as well as the annual effective dose are below the action level recommended by ICRP. The average radon concentration in soil of these villages was about 2.55 ± 0.20 kBqm(-3), and it ranges from 2.08 ± 0.12 kBqm(-3) in the village of Ayn-Jana to 3.62 ± 0.13 kBqm(-3) in the village of Ishtafena.

Artificial semi-rigid tissue sensitized with natural pigments: Effect of photon radiations.

BACKGROUND: A new approach for evaluating the optical penetration depth and testing its validity with Monte Carlo simulations and Kubelka-Munk theory is used for artificial semi-rigid tissue sensitized with natural pigments. Photodynamic therapy is a promising cancer treatment in which a photosensitizing drug concentrates in malignant cells and is activated by visible light at certain wavelength. MATERIALS AND METHODS: Cheap artificial semi-rigid tissue incorporated with scattering and absorbing materials along with some other composites comparable to normal human tissue has been performed. The optical parameters as measured with different conditions and calculated with various techniques are investigated. RESULTS: The probability of interaction of light with tissue is very high when exposed to light in presence of Cichorium pumilum and RBCs followed by photohemolysis or/and photodegradation. The optical penetration depth calculated by linear absorption coefficient ranges from 0.63 to 2.85 mm is found to be comparable to those calculated using Kubelka-Munk theory or Monte Carlo simulation (range from 0.78 to 2.42 mm). The ratio of absorption to the scattering is independent of thickness and decreases with increasing irradiation time. Moreover, the optical parameters as well as their ratios are in very good agreement in the two approaches of calculation. The values of absorption and scattering coefficients are independent of thickness. Furthermore, the average photon ranges in the samples containing no scattering and absorbing materials are about three times greater than those samples containing scattering materials. CONCLUSION: Our results suggest that light propagation with optical properties presented in this work could be applicable in diagnostic and therapeutic of the human biological tissue for photodynamic therapy.

Angular momentum partitioning and hexacontatetrapole moments in impulsively excited argon ions.

We have studied polarized electron collisions with Ar in which the target is simultaneously ionized and excited to form Ar+(3p(4)(1D)4p) states. We measured the integrated Stokes parameters of the subsequent fluorescence emitted by the (2)F(7/2), (2)F(5/2), (2)D(5/2), and (2)P(3/2) states along the direction of electron polarization. The Rubin-Bederson hypothesis is shown to hold for the L and S multipoles of these states. The electric quadrupole and hexadecapole of the 1D core are derived. By recoupling these moments with the electric quadrupole moment of the 4p electron, we calculate higher moments of the total ionic orbital angular momentum, including its hexacontatetrapole (64-pole) moment.