Soil radon (Rn-222) monitoring in a forest site in Fukushima, Japan

Soil radon (Rn-222) has been monitored since August 2013 at three different soil depths on a campus forest of Fukushima University in Japan, where a large amount of fallout nuclides were released by the accident of Fukushima Daiichi Nuclear Power Plant in March 2011. The primary purpose of this study is to evaluate Rn-222 activity level, variability and factors controlling Rn-222 concentration in soil air using data obtained from August to December 2013. Time series of Rn-222 activity concentration showed depth-dependent variability with an equilibrium value (Rn-222(eq)) during this observation period; 7.5, 14 and 23 kBq m(-3) at 0.3, 0.6 and 1.0 m in depth, respectively. Two typhoons passing over the site had a great influence on soil radon level, which was practically used for evaluating effective diffusion coefficient of Rn-222. Transport mechanism of Rn-222 in soil air was considered to be diffusion-controlled with data sets on changing Rn-222 concentration with time in selected cases that showed decreasing (or increasing) Rn-222 concentration with time at every depth. Important factors affecting soil Rn-222 variability are meteorological parameters, low-pressure front passing over the site, and subsequent precipitation. Time lags of decreasing Rn-222 concentration at different depths after rain indicate a certain relationship of Rn-222 level with moving water (and water vapor) in soil. The findings obtained in this study are important to evaluate the fate of fallout nuclides (radiocesium) in contaminated forest sites using soil radon as a tracer of moving soil air

MULTIPLE MYCOTIC ANEURYSMS OF INTERNAL CAROTID ARTERIES CAUSED BY OSTEOMYELITIS OF SKULL Report of a case

We presented a case with multiple mycotic aneurysms of the internal carotid arteries, which were located in the carotid canals and on the base of the skull and considered to be caused by osteomyelitis of the skull, namely extravascular in origin. Carotid angiography showed seven saccular aneurysms with an irregular contour, which were stalked or sessile, one in the right and two in the left at the cavernous portion and two at the canal portion on both sides. No literature was found on the study on the multiple mycotic aneurysms of extravascular origin, located at these portions. Based on the clinical course, the location and multiplicity of the aneurysms, we concluded that thrombophlebitis of the diploic veins and cavernous sinuses occurred secondary to the osteomyelitis of the skull and the microorganisms were transferred into the venous plexuses of the carotid canals by way of the venous system bilaterally, developing the aneurysms of extravascular origin

ROLE OF TRAUMATIC SUBDURAL FLUID COLLECTION IN DEVELOPING PROCESS OF CHRONIC SUBDURAL HEMATOMA

We investigated the role of traumatic subdural fluid collection in the genesis of chronic subdural hematoma (CSDH) in 43 consecutive patients with traumatic subdural fluid collection. Traumatic subdural fluid collection was found in 43 (6%) of 715 patients who underwent CT scans because of head injury. Twenty-four of the 43 patients were more than 65 years of age and this problem occurred in 30% of the 79 head-injured patients over 65 years of age. In 20 (Group 1) of the 43 patients CSDH subsequently developed. During the same period, 30 other patients were treated for CSDH. Twenty-four (Group 2) of these 30 patients had a history of head injury more than two weeks prior to the developing sings and symptoms and had hyper- or iso-dense hematomas on their first CT scan. It may have been that they too first had a traumatic subdural collection. Forty to sixty percent of the patients with asymptomatic traumatic subdural fluid collection may develop CSDH, and this may occur especially in the older patients. Careful observations after the head injury are particularly important in the aged because of the frequent occurrence of traumatic subdural fluid collection and the subsequent development of CSDH