Angioplasty of atheromatous hemodynamic stenoses of intracranial vertebral arteries

We describe three patients presenting transient ischemic attacks or minor stroke, relapsing despite anticoagulation and antiplatelet therapy, in relation to tight stenosis of the intracranial vertebral arteries, without functional communicating arteries. Percutaneous transluminal angioplasty was successfully performed. We have a 6, 24 and 36 months follow-up. After a review of the literature, we discuss indication and risks of this procedure.     

MOOSE: A parallel computational framework for coupled systems of nonlinear equations

Systems of coupled, nonlinear partial differential equations (PDEs) often arise in simulation of nuclear processes. MOOSE: Multiphysics Object Oriented Simulation Environment, a parallel computational framework targeted at the solution of such systems, is presented. As opposed to traditional data-flow oriented computational frameworks, MOOSE is instead founded on the mathematical principle of Jacobian-free Newton–Krylov (JFNK). Utilizing the mathematical structure present in JFNK, physics expressions are modularized into “Kernels,” allowing for rapid production of new simulation tools. In addition, systems are solved implicitly and fully coupled, employing physics-based preconditioning, which provides great flexibility even with large variance in time scales. A summary of the mathematics, an overview of the structure of MOOSE, and several representative solutions from applications built on the framework are presented.     

Asking questions changes behavior: Mere measurement effects on frequency of blood donation.

Objective: This research examined the impact of completing a questionnaire about blood donation on subsequent donation behavior among a large sample of experienced blood donors. Design: Participants (N = 4672) were randomly assigned to an experimental condition that received a postal questionnaire measuring cognitions about donation or a control condition that did not receive a questionnaire. Main Outcome Measures: Number of registrations at blood drives and number of successful blood donations were assessed using objective records both 6 months and 12 months later. Results: Findings indicated that, compared to control participants, the mean frequency of number of registrations at blood drives among participants in the experimental group was 8.6% greater at 6 months (p     

Hydroxyapatite coating by sol–gel on Ti–6Al–4V alloy as drug carrier

In this study Ti–6Al–4V samples were used as substrates and Ca–P layers were deposited using sol–gel technique and covered by spin-coating. The efficiency of hydroxyapatite (HA) coatings as drug carrier was also evaluated by immersion in gentamicin sulphate solution and the release profiles were obtained by cumulative method of the coating samples. Three non-linear mathematical methods were employed in order to discuss a possible mechanism to lead the drug release. Physical chemical techniques showed the presence of the typical absorption bands of calcium phosphates by infrared spectroscopy while X-ray diffraction peaks matched up with hydroxyapatite patterns. Microstructural techniques (SEM, EDS) help to confirm the hydroxyapatite coating by surface aspect and Ca/P ratio (1.64). The best fitting according statistical results explained each stage of the released profiles and correspond to a mixture of short initial burst effect plus drug dissolution with a specific kinetic and the diffusion of the gentamicin solid particles.     

Influence of surface pretreatment and electrocoating parameters on the adhesion of cathodic electrocoat to the Al alloy surfaces

Adhesion of cathodic electrocoat films to the aluminum alloys 2024-T3 bare and Alclad 2024-T3 with different pretreatments and with different cathodic electrocoat process parameters was investigated. The pretreatments studied were acetone wipe and alkaline cleaning. The cathodic electrocoat process parameters studied include variation of cathodic electrocoating voltage and time. Adhesion performance was evaluated by measuring the delamination time and percent delamination of the electrocoat from the alloy surface by placing the small specimen of the sample in the N-methyl pyrrolidinone (NMP) solution at 60°C until the film lifts off or for 2 h whichever comes first. NMP times for electrodeposited film delamination from alkaline cleaned surfaces were found to be higher than the acetone wiped and or those of as-supplied metal surfaces. There was not much effect of acetone cleaning of these alloy surfaces on the adhesion performance of the cathodic electrocoat. The voltage–current (of cathodic electrocoating process) relationships for alkaline cleaned surfaces were also found to be significantly different from the other two types of surfaces. The NMP times of cathodic electrocoat delamination at lower cathodic electrocoating voltage and lower electrocoating times were higher than those at higher cathodic electrocoating voltage and electrocoating times for alkaline cleaned 2024 bare surfaces. Electrocoat thickness developed on the surfaces during the electrodeposition process increased with increasing electrodeposition voltage and time as anticipated.     

On the contribution of external cost calculations to energy system governance: The case of a potential large-scale nuclear accident

The contribution of nuclear power to a sustainable energy future is a contested issue. This paper presents a critical review of an attempt to objectify this debate through the calculation of the external costs of a potential large-scale nuclear accident in the ExternE project. A careful dissection of the ExternE approach resulted in a list of 30 calculation steps and assumptions, from which the 6 most contentious ones were selected through a stakeholder internet survey. The policy robustness and relevance of these key assumptions were then assessed in a workshop using the concept of a ‘pedigree of knowledge’. Overall, the workshop outcomes revealed the stakeholder and expert panel's scepticism about the assumptions made: generally these were considered not very plausible, subjected to disagreement, and to a large extent inspired by contextual factors. Such criticism indicates a limited validity and useability of the calculated nuclear accident externality as a trustworthy sustainability indicator. Furthermore, it is our contention that the ExternE project could benefit greatly – in terms of gaining public trust – from employing highly visible procedures of extended peer review such as the pedigree assessment applied to our specific case of the external costs of a potential large-scale nuclear accident.     

Umbilical arterial S-nitrosothiols in stressed newborns: role in perinatal circulatory transition

S-Nitrosothiols are potent endogenous vasodilators recently found to be in greater concentrations in fetal umbilical venous than arterial blood. We hypothesized that neonatal increases in SNOs may be involved in the normal human perinatal circulatory transition. Paired human umbilical artery and vein plasma samples were collected after birth. S-Nitrosothiol concentrations were measured as NO after photolysis--and NO3- after reduction in vanadium chloride--by chemiluminescence. Normal umbilical arterial serum SNO levels were nearly twice those of matched venous samples but were low in infants who did not transition normally to neonatal circulation. There was no difference in the concentration of NO3- between the normal and depressed infants. The parallel failure of some fetuses to switch both to a normal arteriovenous SNO relationship and a normal clinical post-partum state suggests that SNOs may be involved in the perinatal circulatory transition.     

Arteriovenous fistulae complicating central venous catheterization: value of endovascular treatment based on a series of seven cases

OBJECTIVES: To point out the usefulness and effication of endovascular treatment of arteriovenous fistulae complicating the insertion of central venous catheter. MATERIAL AND METHOD: Retrospective study of 7 cases treated between 1983 and 1993. The central venous catheterization had involved the right internal jugular vein in 5 cases and the right subclavian vein in 2 cases. RESULTS: Isolated endovascular therapy was performed in 5 cases. Surgery was necessary in 1 case to remove an hematoma. In another case, occlusion of a large AVF was performed during intraoperative endovascular temporary occlusion of the AVF. The choice of the occluding agent was primarily dictated by the hemodynamic and anatomical conditions (releasable balloons, coils). Vertebro-vertebral fistulae (3 cases) could be treated with patency of this vessel. No complications were encountered. CONCLUSION: Endovascular approach is a reliable and safe method to perform occlusion of post catheter AVF.