Carbon Composites for the Immobilization of Long-Lived Radio-Nuclides for the Purpose Their Disposal and Transmutation, Part 1

There is presented the review of publications connecting with creation of matrices for the immobilization of long-lived radionuclides and radioactive waste for storage and disposal, as well as for the transmutation. This paper substantiates the practicability and feasibility of obtaining the carbon matrces by carbonization of imidoderivatives.

Angiographic evaluation and management of acute gastrointestinal hemorrhage

Although most cases of acute nonvariceal gastrointestinal hemorrhage either spontaneously resolve or respond to medical management or endoscopic treatment,there are still a significant number of patients who require emergency angiography and transcatheter treatment.Evaluation with noninvasive imaging such as nuclear scintigraphy or computed tomography may localize the bleeding source and/or confirm active hemorrhage prior to angiography.Any angiographic evaluation should begin with selective catheterization of the artery supplying the most likely site of bleeding,as determined by the available clinical,endoscopic and imaging data.If a hemorrhage source is identified,superselective catheterization followed by transcatheter microcoil embolization is usually the most effective means of successfully controlling hemorrhage while minimizing potential complications.This is now wellrecognized as a viable and safe alternative to emergency surgery.In selected situations transcatheter intra-arterial infusion of vasopressin may also be useful in controlling acute gastrointestinal bleeding.One must be aware of the various side effects and potential complications associated with this treatment,however,and recognize the high re-bleeding rate.In this article we review the current role of angiography,transcatheter arterial embolization and infusion therapy in the evaluation and management of nonvariceal gastrointestinal hemorrhage.

Early Solar System Solar Wind Implantation of ⁷Be into Calcium-Alumimum Rich Inclusions in Primitive Meteortites

The one time presence of short-lived radionuclides (SLRs) in Calcium-Aluminum Rich inclusions (CAIs) in primitive meteorites has been detected. The solar wind implantation model (SWIM) is one possible model that attempts to explain the catalogue of SLRs found in primitive meteorites. In the SWIM, solar energetic particle (SEP) nuclear interactions with gas in the proto-solar atmosphere of young stellar objects (YSOs) give rise to daughter nuclei, including SLRs. These daughter nuclei then may become entrained in the solar wind via magnetic field lines. Subsequently, the nuclei, including SLRs, may be implanted into CAI precursors that have fallen from the main accretion flow which had been destined for the proto-star. This mode of implanting SLRs in the solar system is viable, and is exemplified by the impregnation of the lunar surface with solar wind particles, including SLRs. X-ray luminosities have been measured to be 100,000 times more energetic in YSOs, including T-Tauri stars, than present-day solar luminosities. The SWIM scales the production rate of SLRs to nascent SEP activity in T-Tauri stars. Here, we model the implantation of 7Be into CAIs in the SWIM, utilizing the enhanced SEP fluxes and the rate of refractory mass inflowing at the X-region, 0.06 AU from the proto-Sun. Taking into account the radioactive decay of 7Be and spectral flare variations, the 7Be/9Be initial isotopic ratio is found to range from 1 × 10−5 to 5 × 10−5.

Calculation of ¹⁰Be &¹⁴C Production Rates in the Solar Atmosphere: Implications for Solar Flare Spectral Index

Production rates for the short-lived radionuclides 10Be (T1/2=1.36Myr) and14C(T1/2=5730 yr) in the solar atmosphere were calculated. As both radionuclides are produced through spallation reaction of solar energetic particles (SEP) with oxygen as the primary target, the prevalence of each radionuclide is linked. For the calculations, we assumed power law distribution for SEP with spectral index, r, ranging from 2.5 to 4. We find the 10Be and14Cflux rate at the surface of the Sun to range from 0.007 cm﹣2.s﹣1 to 2.55 cm﹣2.s﹣1 for 10Be, and from 0.13 cm﹣2.s﹣1 to 24.13 cm﹣2.s﹣1 for14C. These radio-nuclides are then entrained in the solar wind. From these flux rate calculations and comparison with experimentally measured flux rates ,we find the most likely time averaged solar flare spectral index to be r = ~3.3.