ABSTRACT
Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown.
ABSTRACT
AIM: 1. To present an epidemiological (population and clinical) study of congenital heart defects (CHD) in Croatia in a 16-year period (1995-2011). 2. To analyze outcomes of surgical procedures for all patients in a five-year period (2002-2007) and to compare the results between Croatian and foreign centers. 3. To present the progress in surgical care of CHD in Croatia while acknowledging the requirement of achieving postsurgical mortality rate of below 5%. 4. To evaluate the projection of positive development of CHD management in Croatia in cooperation with major cardiac surgical centers in the neighboring countries. METHODS: Population study includes all children born from 1995 to 2000 and from 2002 to 2007 included in a database modeled by EUROCAT and BWIS. Outcome analysis was made using two models (ABC and RACHS-1) with early mortality rating and prolonged length of stay. Results: Based on two separate studies, mean value of CHD prevalence in Croatia is 7.6 per thousand. Outcome analysis according to the two mentioned evaluation models for the 2002-2007 period shows that children operated on in Croatia had a lower level of complexity compared to the complexity of those sent to foreign centers, but early mortality was below the assigned margin of 5% and there were also no differences in prolonged length of stay. As much as 63% of surgeries in the period were performed abroad, while the remaining 37% were performed in Croatia (351:202). In the following four-year period (2008-2011) there was a significant increase in the number of surgeries performed in Croatia when compared to those performed abroad (59:4% or 380:264). Independent EACTS analysis points to a positive trend of gradual increase in the number of surgeries and acceptance of higher complexity level of surgeries performed in Croatia, while maintaining the assigned margin (early mortality below 5%). Contribution: Proper selection of patients according to the complexity of cardiac surgical procedure is a prerequisite for both low mortality and fewer postsurgical complications. Professional advance relying on close cooperation with foreign centers is much faster and more acceptable than by "learning curves". CONCLUSION: Pediatric cardiac surgery in the developing countries must rely on the experiences of developed cardiac surgical centers in the neighboring countries due to complexity of congenital heart defects. Pediatric cardiology is inherently a public health problem, but the problem exacerbates with the appearance of a large number of adults with congenital heart defects (GUCH patients).
