ABSTRACT
Objective: Randomized controlled trials demonstrate the effectiveness of expectation-focused interventions in improving recovery outcomes following cardiac surgery. For dissemination in routine health care, it is important to capture the perspective of affected individuals. This qualitative study explores the perceived benefits and intervention-specific needs of patients who received expectation-focused intervention in the context of heart valve surgery. In addition, it explores potential barriers and adverse effects. Methods: As part of an Enhanced Recovery After Surgery (ERAS) program within a multicentered randomized controlled trial, patients undergoing minimally invasive heart valve surgery received an intervention focused on their expectations. Six weeks after the intervention, semi-structured interviews were conducted with 18 patients to assess its feasibility, acceptance, barriers, benefits, and side effects. The transcribed interviews were analyzed using qualitative content analysis. Results: The results indicate that both the intervention and the role of the patient and psychologist are key aspects in evaluating the expectation-focused intervention. Five key themes emerged from the patients' perspective: personal needs, expectations and emotions, relationship, communication, and individuality. Patients valued the preparation for surgery and recovery and the space for emotions. Establishing a trustful relationship and addressing stigmatization were identified as primary challenges within the intervention. Conclusion: Overall, patients experienced the expectation-focused intervention as helpful and no adverse effects were reported. Perceived benefits included enhanced personal control throughout the surgery and recovery, while the potential barrier of stigmatization towards a psychologist may complicate establishing a trustful relationship. Addressing personal needs, as a relevant topic to the patients, could be achieved through additional research to identify the specific needs of different patient subgroups. Enhancing the expectation-focused intervention could involve the implementation of a modular concept to address individual needs better.
ABSTRACT
We provide evidence of low-temperature hydrogen evolution and possible hydrogen trapping in an anthracite coal derivative, formed via reactive ball milling with cyclohexene. No molecular hydrogen is added to the process. Raman-active molecular hydrogen vibrations are apparent in samples at atmospheric conditions (300 K, 1 bar) for samples prepared 1 year previously and stored in ambient air. Hydrogen evolves slowly at room temperature and is accelerated upon sample heating, with a first increase in hydrogen evolution occurring at approximately 60 degrees C. Subsequent chemical modification leads to the observation of crystalline carbons, including nanocrystalline diamond surrounded by graphene ribbons, other sp2-sp3 transition regions, purely graphitic regions, and a previously unidentified crystalline carbon form surrounded by amorphous carbon. The combined evidence for hydrogen trapping and carbon crystallization suggests hydrogen-induced crystallization of the amorphous carbon materials, as metastable hydrogenated carbons formed via the high-energy milling process rearrange into more thermodynamically stable carbon forms and molecular hydrogen.
ABSTRACT
A graphite exfoliation technique, using intercalation of a concentrated sulfuric/nitric acid mixture followed by a thermal shock, has successfully exfoliated a herringbone graphite nanofiber (GNF). The exfoliated GNF retains the overall nanosized dimensions of the original GNF, with the exfoliation temperature determining the degree of induced defects, lattice expansion, and resulting microstructure. High-resolution transmission electron microscopy indicated that the fibers treated at an intermediate temperature of 700 degrees C for 2 min had dislocations in the graphitic structure and a 4% increase in graphitic lattice spacing to 3.5 A. The fibers treated at 1000 degrees C for 36 h were expanded along the fiber axis, with regular intervals of graphitic and amorphous regions ranging from 0.5 to >50 nm in width. The surface area of the starting material was increased from 47 m(2)/g to 67 m(2)/g for the 700- degrees C treatment and to 555 m(2)/g for the 1000- degrees C treatment. Hydrogen uptake measurements at 20 bar indicate that the overall hydrogen uptake and operative adsorption temperature are sensitive to the structural variations and graphitic spacing. The increased surface area after the 1000- degrees C treatment led to a 1.2% hydrogen uptake at 77 K and 20 bar, a 3-fold increase in hydrogen physisorption of the starting material. The uptake of the 700- degrees C-treated material had a 0.29% uptake at 300 K and 20 bar; although low, this was a 14-fold uptake over the starting material and higher than other commonly used pretreatment methods that were tested in parallel. These results suggest that selective exfoliation of a nanofiber is a means by which to control the relative binding energy of the hydrogen interaction with the carbon structure and thus vary the operative adsorption temperature.
