A novel Fontan Y-graft for interrupted inferior vena cava and azygos continuation

OBJECTIVES To evaluate the hemodynamicdynamic advantage of a new Fontan surgical template that is intended for complex single-ventricle patients with interrupted inferior vena cava-azygos and hemi-azygos continuation. The new technique has emerged from a comprehensive pre-surgical simulation campaign conducted to facilitate a balanced hepatic flow and somatic Fontan pathway growth after Kawashima procedure. METHODS For 9 patients, aged 2 to18 years, majority having poor preoperative oxygen saturation, a pre-surgical computational fluid dynamics customization is conducted. Both the traditional Fontan pathways and the proposed novel Y-graft templates are considered. Numerical model was validated against in vivo phase-contrast magnetic resonance imaging data and in vitro experiments. RESULTS The proposed template is selected and executed for 6 out of the 9 patients based on its predicted superior hemodynamic performance. Pre-surgical simulations performed for this cohort indicated that flow from the hepatic veins (HEP) do not reach to the desired lung. The novel Y-graft template, customized via a right- or left-sided displacement of the total cavopulmonary connection anastomosis location resulted a drastic increase in HEP flow to the desired lung. Orientation of HEP to azygos direct shunt is found to be important as it can alter the flow pattern from 38% in the caudally located direct shunt to 3% in the cranial configuration with significantly reversed flow. The postoperative measurements prove that oxygen saturation increased significantly (P-value = 0.00009) to normal levels in 1 year follow-up. CONCLUSIONS The new Y-graft template, if customized for the individual patient, is a viable alternative to the traditional surgical pathways. This template addresses the competing hemodynamic design factors of low physiological venous pressure, high postoperative oxygen saturation, low energy loss and balanced hepatic growth factor distribution possibly assuring adequate lung development. Date and number of IRB approval 25 October 2019, 280011928-604.01.01

Miscibility of methylmethacrylate-co-methacrylic acid polymer with magnesium, zinc, and manganese sulfonated polystyrene ionomers

The miscibility of methyl methacrylate-co-methacrylic acid polymer (MMA-MAA) with metal neutralized sulfonated polystyrene ionomers was investigated by viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared radiation spectroscopy (FTIR) techniques. Polystyrene (PS) was sulfonated by acetic anhydride and sulfuric acid and the sulfonation degree was found to be 2.6 mole percent, and 2.6 mole percent sulfonated polystyrene was neutralized by Mg, Zn, and Mn salts. The miscibility behavior of the blends of MMA-MAA with Mg neutralized 2.6 mole% sulfonated polystyrene (2.6MgSPS), Mn neutralized 2.6mole% sulfonated polystyrene (2.6MnSPS), and Zn neutralized 2.6 mole% sulfonated polystyrene (2.6ZnSPS) was investigated by dilute solution viscometry. The results showed that 2.6MgSPS blends were miscible with MMA-MAA in all compositions, 2.6ZnSPS blends were all immiscible, and 2.6MnSPS blends were immiscible at certain compositions. Even though the DSC thermograms of samples were taken in the solid state, they showed consistency with the results of dilute solution viscometry with a few exceptions. DSC results indicated that 2.6ZnSPS was immiscible with MMA-MAA as 2.6MnSPS and 2.6ZnSPS blends were immiscible at certain compositions. FTIR studies of miscible and immiscible blends revealed the existence of specific interactions between carbonyl oxygen of MMA-MAA copolymer and neutralizing cation of the sulfonated polystyrene

Calculation of the Relaxation Time and the Activation Energy Close to the Lower Phase Transition in Imidazolium Perchlorate

The temperature dependence of the relaxation time of imidazolium perchlorate (Im-ClO4) was calculated from the pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models close to the first-order phase transition temperature of 247 K. This calculation was performed in terms of the proton second moment M2 that was associated with the order parameter which was predicted from the mean-field theory. Our results were in good agreement with the observed data. In addition, values of the activation energy were deduced in terms of the Arrhenius plot using our calculated values of the relaxation time from both PS and EF models

Meeting Agenda Matters: Promoting Reflective Dialogue in Teacher Communities

Reflective dialogue as a job-embedded teacher professional learning activity has still been an unexplored area. Little is known about what factors affect its emergence. This study addresses this gap by examining the effect of the frequency of occurrence of particular meeting agendas on the emergence of reflective dialogue in teacher communities as well as what conditions are conducive to promote reflective dialogue. Using a mixed methods research design, first, we created a single-level multiple-indicators multiple-causes model. Through a focus group interview we delved deep into reflective dialogue. In the quantitative part, we found that the conversations on the goals of the school, curriculum, and student learning contributed to the evolution of reflective dialogue among teachers as these topics are more important. As teachers focus more on discussing these three topics, they begin reflecting on their practice through a collaborative dialogue. The follow-up qualitative study revealed that there are more topics that might promote reflective dialogue. Personal and institutional conditions have been revealed as being necessary for creating culture of reflective dialogue. For school leaders, practical solutions to promote reflective dialogue were provided. For researchers, future research directions were suggested to obtain a fuller picture of reflective dialogue across schools. © 2018, © 2018 International Professional Development Association (IPDA)

Phenomenological approaches on the Nd3+ doped ferroelectric LaBGeO5

Two phenomenological models, namely the compressible Ising model and Landau model, have been used to analyze the specific heat and the dielectric constant data, respectively for the pure and Nd3+ doped LaBGeO5 (LBG) crystals. The critical exponent of the specific heat was extracted in both ferroelectric and paraelectric phases of the crystals studied here within the temperature intervals of [T - T-C vertical bar < 4 K. The extracted values of the critical exponent were then used to predict some thermodynamic quantities such as the enthalpy, entropy, and the Gibbs free energy. Regarding the analysis of dielectric constant data within the framework of the Landau theory, the observed values of the birefringence were associated with the order parameter below the transition temperature T-c. The Landau coefficients a(0) and a(4) were determined. Our results indicate a second-order phase transition mechanism

Case report: Cerebral superficial siderosis: MRI findings [Serebral süperfisyal siderozis: MRG bulgulari.]

PubMed ID: 14661289Superficial siderosis of the central nervous system is a rare condition characterized by deposition of hemosiderin in the leptomeninges, subpial tissue and spinal cord. Magnetic resonance imaging provides prompt diagnosis of this entity. Three cases of cerebral superficial siderosis are presented in this study. On T2-weighted images, typical hypointense rims were observed under the brain surface. In one patient, there was also spinal superficial siderosis findings