Parallel intercostal artery stenting and exclusion of symptomatic bucket-handle intercostal patch aneurysm.

Intercostal patch aneurysms after open thoracoabdominal aneurysm repair represent a challenging pathology, with highly variable patient anatomy and spinal cord ischemia risk. We present a case of a 51-year-old man with a large symptomatic "bucket-handle" loop graft intercostal patch aneurysm, which was treated with endovascular exclusion with concurrent parallel intercostal stent grafting. This case highlights specialized endovascular techniques to treat intercostal patch aneurysms and the necessity of meticulous operative case planning in both open and endovascular thoracoabdominal aneurysm repair.

Molecular-Level Overhaul of γ-Aminopropyl Aminosilicone/Triethylene Glycol Post-Combustion CO2 -Capture Solvents.

Capturing carbon dioxide from post-combustion gas streams is an energy-intensive process that is required prior to either converting or sequestering CO2 . Although a few commercial 1st and 2nd generation aqueous amine technologies have been proposed, the cost of capturing CO2 with these technologies remains high. One approach to decrease costs of capture has been the development of water-lean solvents that aim to increase efficiency by reducing the water content in solution. Water-lean solvents, such as γ-aminopropyl aminosilicone/triethylene glycol (GAP/TEG), are promising technologies, with the potential to halve the parasitic load to a coal-fired power plant, albeit only if high solution viscosities and hydrolysis of the siloxane moieties can be mitigated. This study concerns an integrated multidisciplinary approach to overhaul the GAP/TEG solvent system at the molecular level to mitigate hydrolysis while also reducing viscosity. Cosolvents and diluents are found to have negligible effects on viscosity and are not needed. This finding allows for the design of single-component siloxane-free diamine derivatives with site-specific incorporation of selective chemical moieties for direct placement and orientation of hydrogen bonding to reduce viscosity. Ultimately, these new formulations are less susceptible to hydrolysis and exhibit up to a 98 % reduction in viscosity compared to the initial GAP/TEG formulation.

Use of an abdominal reapproximation anchor system in the closure of large, open myelomeningoceles.

Open neural tube defects are complex congenital abnormalities of the nervous system in which nervous tissue is exposed on the patient's back at the time of delivery. These malformations require surgical correction, and although replacement of the neural placode internally is fairly standard, providing skin closure can be very challenging especially in large defects. An abdominal reapproximation anchor (ABRA) device may be of value in attaining skin closure in these large, open myelomeningocele defects in which primary closure cannot be accomplished surgically. In a study period during which 65 patients underwent surgical closure of open myelomeningocele defects, 5 of them underwent ABRA-assisted closure.The average surgical intervention for myelomeningocele repair occurred on day 2.2 of life (range 2-3 days). The average defect size was 37 cm2 (range 16-56 cm2), and the average time to formal closure was 30.8 days (range 8-63 days). One of the patients had natural closure with just ABRA approximation. The remaining 4 patients underwent formal delayed primary closure when the skin edges became approximated. Use of the ABRA system in the closure of a large, open myelomeningocele may be valuable in select patients but requires further follow-up and comparison to identify truly significant differences with traditional techniques.

A computational study of the heats of reaction of substituted monoethanolamine with CO2.

Various amines have been considered as materials for chemical capture of CO(2) through liquid-phase reactions to form either carbamate or carbamic acid products. One of the main challenges in these CO(2)-amine reactions lies in tuning the heat of reaction to achieve the correct balance between the extent of reaction and the energy cost for regeneration. In this work, we use a computational approach to study the effect of substitution on the heats of reaction of monoethanolamine (MEA). We use ab initio methods at the MP2/aug-cc-pVDZ level, coupled with geometries generated from B3LYP/6-311++G(d,p) density functional theory along with the conductor-like polarizable continuum model to compute the heats of reaction. We consider two possible reaction products: carbamate, having a 2:1 amine:CO(2) reaction stoichiometry, and carbamic acid, having a 1:1 stoichiometry. We have considered CH(3), NH(2), OH, OCH(3), and F substitution groups at both the α- and ß-carbon positions of MEA. We have experimentally measured heats of reaction for MEA and both α- and ß-CH(3)-substituted MEA to test the predictions of our model. We find quantitative agreement between the predictions and experiments. We have also computed the relative basicities of the substituted amines and found that the heats of reaction for both carbamate and carbamic acid products are linearly correlated with the computed relative basicities. Weaker basicities result in less exothermic heats of reaction. Heats of reaction for carbamates are much more sensitive to changes in basicity than those for carbamic acids. This leads to a crossover in the heat of reaction so that carbamic acid formation becomes thermodynamically favored over carbamate formation for the weakest basicities. This provides a method for tuning the reaction stoichiometry from 2:1 to 1:1.

Aminosilicone solvents for CO(2) capture.

This work describes the first report of the use of an aminosilicone solvent mix for the capture of CO(2). To maintain a liquid state, a hydroxyether co-solvent was employed which allowed enhanced physisorption of CO(2) in the solvent mixture. Regeneration of the capture solvent system was demonstrated over 6 cycles and absorption isotherms indicate a 25-50 % increase in dynamic CO(2) capacity over 30 % MEA. In addition, proof of concept for continuous CO(2) absorption was verified. Additionally, modeling to predict heats of reaction of aminosilicone solvents with CO(2) was in good agreement with experimental results.

Palladium-Catalyzed Carbonylation and Coupling Reactions of Aryl Chlorides and Amines.

The palladium-catalyzed amidation of electron-deficient aryl chlorides proceeds readily in the presence of low CO pressures and a slight excess of an iodide salt. The rates of amidation are accelerated over those without added salt, and iodide is preferred over bromide or chloride. More electron-rich aryl chlorides were not effectively amidated, either with or without added iodide. We postulate that an intermediate anionic palladium(0) iodide complex is responsible for the enhanced reactivity.