Diagnosis of lipomatous hypertrophy of the atrial septum by two-dimensional echocardiography

Originally described in 1964, lipomatous hypertrophy of the atrial septum currently remains a diagnosis established primarily at autopsy. Clinical interest in this disorder has centered on the reported association with supraventricular arrhythmias and sudden death. Because two-dimensional echocardiography allows detailed assessment of atrial septal configuration, we reviewed two-dimensional echocardiographic reports obtained over a 1 year period and identified 17 patients who had features consistent with lipomatous hypertrophy of the atrial septum. Nine were men and the average age was 70 years. Autopsy confirmation of the echographic findings was possible in one patient. In nine patients, ideal body weight was exceeded by 10% or more. The atrial septum viewed from the subcostal transducer position showed a distinctive echo-dense globular thickening sparing the valve of the fossa ovalis. The resultant tomographic image of the atrial septum had a characteristic dumbbell appearance. The mean thickness of the atrial septum was 21 mm (range 15 to 29). Seven patients had supraventricular arrhythmias, and eight had P wave abnormalities.The two-dimensional echocardiographic features described are distinctive and suggest that this technique is the procedure of choice not only for establishing the diagnosis of lipomatous hypertrophy of the atrial septum but also for providing a means for prospective follow-up of patients with this little known entity

Two-dimensional echocardiographic spectrum of univentricular atrioventricular connection

The spectrum of anomalies in hearts having a univentricular atrioventricular (AV) connection was examined by two-dimensional echocardiography in 183 patients and the anatomic findings were compared with angiography. The mode of AV connection was found to be of three types: 1) double inletvia two A V valves; 2) singleinlet via one AV valve with absence of the other (left or right AV valve atresia); and 3) common inletvia a common AV valve. Identification of an accessory chamber by two-dimensional echocardiography was possible with 90% sensitivity, but it was limited compared with angiography in patients with severely hypoplastic anterior Chambers and pulmonary valve atresia. All patients with subaortic outlet foramen obstruction were detected. Great artery position and the presence of obstruction to pulmonary flow were correctly predicted in all but one patient. Two-dimensional echocardiography was superior to angiography for the detection of AV valve abnormalities which were present in 27% and included abnormal chordae, hypoplasia or dysplasia of either valve. Two-dimensional echocardiography should play an essential role in the complete preoperative assessment of patients with univentricular AV connection

Intravascular ultrasound imaging: In vitro validation and pathologic correlation

AbstractIntravascuiar ultrasound imaging is a new method in which high resolution images of the arterial wall are obtained with use of a catheter placed within an artery. An in vitro Plexiglas well model was used to validate measurements of the luminal area, and an excellent correlation was obtained. One hundred thirty segments of fresh peripheral arteries underwent ultrasound imaging and the findings were compared with the corresponding histopathologic sections. luminal areas determined with ultrasound imaging correlated well with those calculated from microscopic slides (r = 0.98).Three patterns were identified on the ultrasound images: 1) distinct interface between media and adventitia, 2) indistinct interface between media and adventitia but different echo density layers, and 3) diffuse homogeneous appearance. The types of patterns depended on the relative composition of the and adventitia. Calcification of intimal plaque obscured underlying structures. Atherosclerotic plaque was readily visualized but could not always be differentiated from the underlying media

Non-Equilibrium Pathways for Excitation of Bulk and Surface Phonons through Anharmonic Coupling

Upon impulsive optical excitation of solid-state materials, the non-equilibrium flow of energy from the excited electronic system to the lattice degrees of freedom typically happens in a few picoseconds. Here we identified the surface of thin Bi films grown on Si(001) as an additional subsystem which is excited much slower on a 100 ps timescale that is caused by decoupling due to mismatched phonon dispersions relations of bulk and surface. Anharmonic coupling among the phonon systems provides pathways for excitations which exhibits a 1/T-dependence causing a speed-up of surface excitation at higher temperatures. A quantitative justification is provided by phonon Umklapp processes from lattice thermal conductivity of the Bi bulk. Three-temperature model simulations reveal a pronounced non-equilibrium situation up to nanoseconds: initially, the surface is colder than the bulk, that situation is then inverted during cooling and the surface feeds energy back into the bulk phonon system

Architecture and Design of the McMaster NEUDOSE Communication Radio Subsystem

The communication subsystem is responsible for ensuring robust communication between the McMaster NEUDOSE CubeSat and the Ground Station located at McMaster University. This subsystem sends the collected scientific data, system telemetry (health), and telecommand from the onboard instruments using two different communication radio frequencies

Intraoperative evaluation of mitral valve regurgitation and repair by transesophageal echocardiography: Incidence and significance of systolic anterior motion

AbstractObjectives. This study was designed to delineate the utility and results of intraoperative transesophageal echocardiography in the evaluation of patients undergoing mural valve repair for mitral regurgitation.Background. Mitral valve reconstruction offers many advantages over prosthetic valve replacement. Intraoperative assessment of valve competence after repair is vital to the effectiveness of this procedure.Methods. Intraoperative transesophageal echocardiography was performed in 143 patients undergoing mitral valve repair over a period of 23 months, Before and after repair, the functional morphology of the mitral apparatus was defined by twodimensional echocardiography; Doppler color flow imaging was used to clarify the mechanism of mitral regurgitation and to semiquantitate its severity.Results. There was significant improvement in the mean mitral regurgitation grade by composite intraoperative transesophageal echocardiography after valve repair (3.6 ± 0.8 to 0.7 ± 0.7; p < 0.00001). Excellent results from initial repair with grade ≤ 1 residual mitral regurgitation were observed in 88.1% of patients. Significant residual mitral regurgitation (grade ≥ 3) was identified in 11 patients (7.7%); 5 underwent prosthetic valve replacement, 5 had revision of the initial repair and 1 patient had observation only. Of the 100 patients with a myxomatous mitral valve, the risk of grade ≥ 3 mitral regurgitation after initial repair was 1.7% in patients with isolated posterior leaflet disease compared with 22.5% in patients with anterior or bileaflet disease.Severe systolic anterior motion of the mitral apparatus causing grade 2 to 4 mitral regurgitation was present in 13 patients (9.1%) after cardiopulmonary bypass. In 8 patients (5.6%), systolic anterior motion resolved immediately with correction of hyperdynamic hemodynamic status, resulting in grade ≤ 1 residual mitral regurgitation without further operative intervention.Transthoracic echocardiography before hospital discharge demonstrated grade ≤ 1 residual mitral regurgitation in 86.4% of 132 patients studied. A significant discrepancy (> 1 grade) in residual mitral regurgitation by predischarge transthoracic versus intraoperative transesophageal echocardiography was noted in 17 patients (12.9%).Conclusions. Transesophageal echocardiography is a valuable adjunct in the intraoperative assessment of mitral valve repair

Critical behavior of the dimerized Si(001) surface: A continuous order-disorder phase transition in the 2D Ising universality class

The critical behavior of the order-disorder phase transition in the buckled dimer structure of the Si(001) surface is investigated both theoretically by means of first-principles calculations and experimentally by spot profile analysis low-energy electron diffraction (SPA-LEED). We use density functional theory (DFT) with three different functionals commonly used for Si to determine the coupling constants of an effective lattice Hamiltonian describing the dimer interactions. Experimentally, the phase transition from the low-temperature $c(4 {\times} 2)$- to the high-temperature $p(2 {\times} 1)$-reconstructed surface is followed through the intensity and width of the superstructure spots within the temperature range of 78-400 K. Near the critical temperature $T_\mathrm{c} = 190.6$ K, we observe universal critical behavior of spot intensities and correlation lengths which falls into the universality class of the two-dimensional (2D) Ising model. From the ratio of correlation lengths along and across the dimer rows we determine effective nearest-neighbor couplings of an anisotropic 2D Ising model, $J_\parallel = (-24.9 \pm 0.9_\mathrm{stat} \pm 1.3_\mathrm{sys})$ meV and $J_\perp = (-0.8 \pm 0.1_\mathrm{stat})$ meV. We find that the experimentally determined coupling constants of the Ising model can be reconciled with those of the more complex lattice Hamiltonian from DFT when the critical behavior is of primary interest. The anisotropy of the interactions derived from the experimental data via the 2D Ising model is best matched by DFT calculations using the PBEsol functional. The trends in the calculated anisotropy are consistent with the surface stress anisotropy predicted by the DFT functionals, pointing towards the role of surface stress reduction as a driving force for establishing the $c(4 {\times} 2)$-reconstructed ground state

Mechanistic Observation of Interactions between Macrophages and Inorganic Particles with Different Densities

Many different types of inorganic materials are processed into nano/microparticles for medical utilization. The impact of selected key characteristics of these particles, including size, shape, and surface chemistries, on biological systems, is frequently studied in clinical contexts. However, one of the most important basic characteristics of these particles, their density, is yet to be investigated. When the particles are designed for drug delivery, highly mobile macrophages are the major participants in cellular levels that process them in vivo. As such, it is essential to understand the impact of particles’ densities on the mobility of macrophages. Here, inorganic particles with different densities are applied, and their interactions with macrophages studied. A set of these particles are incubated with the macrophages and the outcomes are explored by optical microscopy. This microscopic view provides the understanding of the mechanistic interactions between particles of different densities and macrophages to conclude that the particles’ density can affect the migratory behaviors of macrophages: the higher the density of particles engulfed inside the macrophages, the less mobile the macrophages become. This work is a strong reminder that the density of particles cannot be neglected when they are designed to be utilized in biological applications

Eliminacija kloramfenikola u kalifornijskoj pastrvi

Chloramphenicol muscle residue levels in rainbow trout were determined after oral administration of 84 μg kg−1d−1 of chloramphenicol for four days. Samples were taken one day before treatment and for 43 days after the treatment was over. Chloramphenicol was analysed using an in-house enzyme linked immunoassay (ELISA) validated against the criteria of the Commission Decision 2002/657/EC. Validation parameters confi rmed that the method was appropriate for the detection of chloramphenicol at levels below the minimum required performance limit (MRPL) of 0.3 μg kg−1. The highest chloramphenicol levels were observed on the fi rst day after the treatment had ended (144.3 μg kg−1). Elimination was signifi cant over the fi rst seven days; signifi cant differences were detected between days 1 and 3 (p<0.001), 3 and 5 (p<0.001), and 5 and 7 (p<0.05). Chloramphenicol levels dropped below MRPL to 0.17 μg kg−1 on day 9 after the end of treatment. From day 11 to 43, chloramphenicol residues were detectable in a range from 0.091 μg kg−1 (highest) to 0.011 μg kg−1 (lowest). Our results indicate that trout muscle tissue could be compliant with health requirements for consumption 10 days after withdrawal from chloramphenicol treatment.Određivani su ostaci kloramfenikola u mišićnom tkivu kalifornijske pastrve nakon oralne primjene u dozi od 84 μg kg−1d−1 tijekom 4 dana. Uzorkovanje je provedeno dan prije tretmana te tijekom 43 dana nakon tretmana. Maseni udjeli kloramfenikola određivani su primjenom in-house imunoenzimske metode (ELISA) validirane prema kriterijima Odluke Komisije 2002/657/EC. Dobiveni validacijski parametri pokazuju da je metoda prikladna za određivanje kloramfenikola na nivou manjem od vrijednosti granice najmanje zahtijevane učinkovitosti izvedbe metode (MRPL) od 0,3 μg kg−1. Najviši maseni udjeli kloramfenikola utvrđeni su prvog dana nakon završetka tretmana (144,3 μg kg−1). Statistički značajna eliminacija utvrđena je tijekom sedam dana te je značajno smanjenje određeno između prvog i trećeg (p<0,001), trećeg i petog (p<0,001) te petog i sedmog dana nakon tretmana (p<0,05). Razina kloramfenikola ispod MRPL vrijednosti utvrđena je devetog dana (0,17 μg kg−1) nakon tretmana. U vremenu od 11. do 43. dana nakon tretmana određeni su ostaci kloramfenikola od maksimalno 0,091 μg kg−1 do minimalno 0,011 μg kg−1. Prikazani rezultati pokazuju da se 10 dana nakon završetka tretmana tkivo pastrve može smatrati prikladnim za konzumaciju bez potencijalne štete za zdravlje