An Overview of Tokamak Alternatives in the US Fusion Program with the Aim of Fostering Concept Innovation

The US fusion program has operated for just over 50 years, during which time the tokamak has emerged as the most promising vehicle for a burning plasma experiment. However, many other concepts have been built and investigated as alternatives (and possible improvements) to the tokamak, perhaps to make energy from fusion an economic reality sooner. This Paper is an overview of the conventional alternatives to the tokamak and a set of those that are not so conventional with the aim of fostering concept innovation. Usually the devices are grouped into magnetic, inertial, electrostatic, or other categories, with sub-categories. Here, the groupings of conventional- and non-conventional-alternatives are used too. The conventional alternatives are those devices that have been adopted as serious alternatives, and for which many references are immediately available (e.g. rfp, mirror, stellarator, spheromak, laser ICF, etc). The non-conventional alternatives comprise approaches that are not being currently investigated or are worth consideration. In this grouping lie ideas like impact fusion, muon catalyzed fusion, and many historical ones (like the Elmo Bumpy Torus). Several examples of the physics of non-conventional alternatives are presented in summary form as examples of skunkworks in the hope that others will take up the challenge of concept innovation.     

Mortality and neurologic morbidity after repair of traumatic aortic disruption

BACKGROUND: Traumatic disruption of the thoracic aorta frequently results in death before operative repair. The determinants of mortality after repair, however, are uncertain. In addition, intraoperative strategies for reducing the incidence of spinal cord injury remain controversial. METHODS: The records of 45 consecutive patients undergoing repair of traumatic disruption of the thoracic aorta at a single institution during a 9-year period were reviewed in a retrospective fashion. Patient age ranged from 15 to 81 years (mean age, 33.9 years). Twenty-two patients (49%) had multiple associated injuries, and 8 (18%) had isolated aortic injuries. Nine patients (20%) experienced preoperative hypotension (systolic blood pressure of less than 90 mm Hg). Repair was performed with partial bypass in 22 patients, a heparinized shunt in 2, and no distal perfusion (clamp and sew technique) in 21. RESULTS: Nine patient (20%) died after operation. Multivariate logistic regression analysis of preoperative and intraoperative variables identified advancing age and preoperative hypotension as independent predictors of operative death. The presence of associated injuries was not an independent predictor of operative death. All 4 patients with injuries proximal to the aortic isthmus died. Ten patients were excluded from analysis of spinal cord injury either because of preoperative neurologic deficit or because of death before postoperative evaluation. Six (17%) of the remaining 35 patients had development of paraplegia: 5 of the 15 patients having the clamp and sew technique, 1 of the 2 with a shunt, and 0 of the 18 patients with bypass (p < 0.05, clamp and sew versus bypass). In the clamp and sew group, patients in whom paraplegia developed had significantly longer aortic clamp times than those without neurologic injury (40.6 +/- 4.4 minutes versus 28.7 +/- 2.9 minutes, respectively; p < 0.05). CONCLUSIONS: Advancing age, preoperative hypotension, and perhaps injury location are important determinants of death after repair of traumatic disruption of the thoracic aorta. Adjunctive perfusion with partial bypass should be used during repair to reduce the incidence of spinal cord injury.     

Analysis of neural crest cell migration in Splotch mice using a neural crest-specific LacZ reporter

In the last decades, several therapies for unipolar depression have been developed, for example cognitive therapy, behavior therapy and pharmacotherapy. A new kind of therapy is bibliotherapy. What is new in this treatment modality is not the content, because bibliotherapy usually uses a cognitive-behavioral approach. Only the form in which it is presented is new. In bibliotherapy the patient takes a standardized treatment home, in book form, and works it through more or less independently. Contacts with therapists are only supportive or facilitative. No traditional relationship between therapist and patient is developed. In this article the relevance of bibliotherapy for the clinical practice is presented and a meta-analysis of the research into bibliotherapy is described.     

The effect of the chronic internal administration of the new Russian n-3 polyunsaturated fatty acid concentrate--epaden--on blood coagulation system indices in rabbits

Daily oral 6-week administration of epaden in a dose containing 0.3 g eucosopentanoic acid and 0.05 g docosahexaenoic acid caused decrease in collagen-induced platelet aggregation in rabbits in vivo and in the activity of the tissue type plasminogen activator, as well as reduction in the level of antithrombin III cofactor activity. No changes were encountered in ADP-induced aggregation, in the platelet count, in platelet adhesion to collagen, and in activated partial thromboplastin time.     

Defibrillation efficacy with endocardial electrodes is influenced by reductions in cardiac preload

Several studies were undertaken to develop three-dimensional (3-D) cell culture models that allow conditions closer to the in vivo situation. To this end, alginate gels were tested as a 3-D cell culture model that might be useful in the study of the effects of UVA on human dermal fibroblasts. Cell culture in alginate gels and the irradiation conditions were optimized. Results showed that optimized cultures in alginate gels experienced considerable cell death on UVA irradiation compared to the classical monolayer cell culture. Viability tests (cell counting and neutral red assay) were performed to show that only UVA-irradiated alginate gels were responsible for this cytotoxicity. The implication of oxygen species in the phototoxicity induced by ultraviolet light has already been described; for this reason we investigated whether oxygen species were involved in the cytotoxicity induced by alginate upon UVA irradiation. It appeared that superoxide anion is not implicated.     

The quality of friendships between children with and without learning problems

The nature and quality of preadolescent friendships between children with and without learning problems due to mental retardation or mild cognitive difficulties were investigated. Based on an assessment of the reciprocal relationship status of 373 children, including 54 with learning problems, 33 friend and 32 acquaintance dyads were identified. Of these dyads, half included a child with learning problems and half consisted of 2 children without learning problems. The dyads were observed performing a play task. Unlike friendships between children without disabilities, friendships between children with and without learning problems were marked by limited collaboration and shared decision-making, a low level of cooperative play and shared laughter, and an asymmetrical, hierarchical division of roles. The importance of advancing beyond the study of the social acceptance of children with learning problems to study the qualitative aspects of their friendships was discussed.     

Radiolabeling of the rat P2X4 purinoceptor: evidence for allosteric interactions of purinoceptor antagonists and monovalent cations with P2X purinoceptors

The rat recombinant P2X4 purinoceptor was expressed in CHO-K1 cells, and binding studies were performed using the radioligand [35S]adenosine-5'-O-(3-thio)triphosphate ([35S]ATPgammaS). In 50 mM Tris/1 mM EDTA assay buffer, pH 7.4 at 4 degrees, [35S]ATPgammaS bound with high affinity to the P2X4 purinoceptor (KD = 0.13 nM, Bmax = 151 pmol/mg of protein). The purinoceptor agonists ATP and 2-methylthioadenosine triphosphate possessed nanomolar affinity for the P2X4 purinoceptor, whereas the antagonist suramin possessed much lower affinity (IC50 = 0.5 mM). Cibacron blue was more potent than suramin but produced a biphasic competition curve, whereas d-tubocurarine potentiated binding at concentrations in excess of 10 microM. The complex effects of cibacron blue and d-tubocurarine seemed to be due to an allosteric interaction with the P2X4 purinoceptor because these compounds affected radioligand dissociation, measured after isotopic dilution with unlabeled ATPgammaS. Cibacron blue (1-100 microM) and d-tubocurarine (0.1-1 mM) produced rapid (10 sec to 5 min) decreases or increases, respectively, in the level of [35S]ATPgammaS binding measured immediately after initiation of the dissociation reaction. However, the subsequent rates of radioligand dissociation were not markedly different from those measured in their absence. Monovalent cations produced similar affects on the P2X4 purinoceptor and, like d-tubocurarine, increased [35S]ATPgammaS binding. The actions of d-tubocurarine and sodium were not additive. The findings from this study indicate that [35S]ATPgammaS can be used to label the P2X4 purinoceptor and suggest that this binding can be enhanced by monovalent cations and d-tubocurarine and may be subject to negative allosteric modulation to varying degrees by different purinoceptor antagonists.     

241Am removal by DTPA vs. occurrence of skeletal malignancy

PURPOSE: The distribution of hyaluronan (HA) and the cellular response after photokeratitis induced by different ultraviolet (UV) wavelengths in the rabbit cornea was examined to help understand the mechanism of corneal injury and repair after UV damage. HA is a high molecular weight disaccharide polymer capable of binding considerable amounts of water. It is not normally found in the rabbit corneal stroma. The production of HA represents a generalized corneal response to injury. METHODS: Twenty-four albino rabbit corneas were exposed to 270, 290, and 310 nm of UV radiant energy in 8-nm full wavebands in doses producing biomicroscopically significant keratitis (three corneal thresholds for keratitis (Hc): 0.016 J/cm2 for 270 nm, 0.04 J/cm2 for 290 nm, and 0.14 J/cm2 for 310 nm) and in subkeratitis doses (0.7 Hc: 0.004 J/cm2 for 270 nm, 0.008 J/cm2 for 290 nm, and 0.03 J/cm2 for 310 nm). The rabbits exposed to 270 and 290 nm of UV radiation were sacrificed 3 days after exposure. The rabbits exposed to 310 nm of UV radiation were sacrificed 3, 7, and 14 days after exposure, respectively. The corneal tissue specimens were double stained and examined morphologically and histochemically for HA by light microscopy. RESULTS: Evaluation of corneas exposed to 270 and 290 nm of UV radiant energy in both subkeratitis and keratitis doses and those corneas exposed to 310 nm of radiant energy in subkeratitis dose showed neither stromal changes nor production of HA by corneal cells. Corneas exposed to 310 nm of UV radiant energy in keratitis dose at 3 days after exposure showed disappearance of keratocytes in entire thickness of central cornea. Cells bordering this damaged area were staining for HA. By 7 days after exposure almost the whole damaged area, except one fourth of anterior stroma, was repopulated by new keratocytes staining positive for HA. The corneal structures became normal and HA almost completely disappeared 14 days after exposure. CONCLUSIONS: A keratitis dose of 310 nm of UV light irradiation is needed to cause keratocyte damage. A keratitis dose of the shorter wavelengths does not cause keratocyte cell damage at the light microscopic level. The keratocyte production of HA appears to be a sign of cell readiness to repopulate the damaged stroma devoid of keratocytes.