Attila Lovas

Non-invasive in vivo time-dependent strain measurement method in human abdominal aortic aneurysms: Towards a novel approach to rupture risk estimation

We aim to introduce a novel, inverse method for in vivo material parameter identification of human abdominal aortic aneurysms (AAA), which could overcome one of the greatest sources of uncertainty in patient-specific simulations, and could also serve as a rapid, patient-calibrated, novel measure of aneurysm rupture risk. As an initial step, the determination of the kinematic fields is presented here. Images of the AAA lumen, acquired in 10 discrete time-steps through a stabilized cardiac cycle by electrocardiogram-gated computer tomography angiography, are used to approximate the in vivo, time dependent kinematic fields of the arterial wall using a novel, incompressible Kirchhoff-Love shell element implemented into the isogeometric analysis framework. Defining a smoothing parametric surface via 2D bicubic spline fitting in the spatial, and by harmonic regression in the temporal domain, we are able to adequately mitigate the measurement inaccuracy. The ill-posedness of the problem requires certain assumptions on the displacement. In our case, based on numerical fluid structure interaction simulation observations, we hypothesized the incremental displacement vector of the reference surface to coincide with its corrected normal; hence the periodic movement was assured. Finally, we present two examples: an AAA and an undilated calcificated aorta. Strains in the diseased part were compared to those in a healthy arterial section of the same patient and found to have significant differences in both specimens. In the case of AAAs, high spatial gradients surrounding the dilated part indicate abrupt changes in material properties, a phenomenon less significant for the atherosclerotic case.

Invariance of separability probability over reduced states in 4 × 4 bipartite systems

The geometric separability probability of composite quantum systems is extensively studied in the last decades. One of most simple but strikingly difficult problem is to compute the separability probability of qubit-qubit and rebit-rebit quantum states with respect to the Hilbert-Schmidt measure. A lot of numerical simulations confirm the P(rebit-rebit)=29/64 and P(qubit-qubit)=8/33 conjectured probabilities. Milz and Strunz studied the separability probability with respect to given subsystems. They conjectured that the separability probability of qubit-qubit (and qubit-qutrit) depends on sum of single qubit subsystems (D), moreover it depends just on the Bloch radii (r) of D and it is constant in r. Using the Peres-Horodecki criterion for separability we give mathematical proof for the P(rebit-rebit)=29/64 probability and we present an integral formula for the complex case which hopefully will help to prove the P(qubit-qubit)=8/33 probability too. We prove Milz and Strunzs conjecture for rebit-rebit and qubit-qubit states. The case, when the state space is endowed with the volume form generated by the operator monotone function f(x)=sqrt(x) is studied too in detail. We show, that even in this setting the Milz and Strunzs conjecture holds and we give an integral formula for separability probability according to this measure.

Meteorológiai paraméterek változásának hatása a halálos kimenetelű aortaaneurysma-rupturákra

Absztrakt: Bevezetes: Szamos kozlemeny vizsgalta mar az időjarasi parameterek valtozasanak cardiovascularis korkepekre gyakorolt hatasat. Ezek bizonyitottak az aortaaneurysma-ruptura előfordulasanak es az időjaras valtozasanak kapcsolatat is. Nincsenek azonban ismereteink a fugges mertekeről, arrol, hogy mennyire szamottevő tenyezők az egyes időjarasi parameterek ezen halalokok eseten. Celkitűzes: Kutatasunk celja, hogy a halalos kimenetelű aortakatasztrofa nyomas- es hőmersekletvaltozastol valo fuggesenek merteket feltarjuk, a kapcsolat intenzitasat egy uj modszerrel meghatarozzuk. Modszer: A korabban a tudőembolias halalozas es az időjaras osszefuggesenek tanulmanyozasara fejlesztett programunkat futtattuk olyan aortaaneurysmas halaleseteket tartalmazo adatsoron, amelyben az emlitett korkep miatt bekovetkezett aortaruptura vezetett a paciensek halalahoz. A 2005. januar 1. es 2014. januar 1. kozotti időszak eseteit tekintettuk at a Semmelweis Egyetem korbonctani adatbazisaban. 152 aneurysmas esemenyt viz...INTRODUCTION There are several statements about the connection between cardiovascular diseases and climate change. On behalf of our observation-based knowledge we hypothesized a relationship between the occurence of aortic aneurysm (AA) rupture and weather changes. AIM The purpose of our study was to explore the relationship between fatal aortic catastrophe and changes in atmospheric pressure and temperature. By using a new method we could even measure the intensity of the connection. METHOD We have developed a software earlier to examine the link between pulmonary embolism mortality and the weather on data sets comprised of aortic aneurysm cases, where the medical condition had led to the fatal rupture of the aorta. For the events mentioned earlier we used the autopsy database of Semmelweis University between January 1, 2005 and January 1, 2014. Altogether we examined 152 aneurysm-related aortic catastrophes. We reported the exact day of the incident and the weather conditions on that day and the day before. RESULTS AND CONCLUSION We have defined that the occurrence rate of fatal aortic catastrophe showed a slight dependence on the two examined parameters within our groups. We have found the connection related to ruptured aortic aneurysm and changes in atmospheric pressure more significant than their connection with mean daily temperatures. With the increase in atmospheric pressure, the rate of AA mortality also increased. In the knowledge of our results we believe that the mathematical model we used can be an effective starting point for population-based and prospective studies. Orv Hetil. 2018; 159(37): 1501-1505.

Refinement of Robertson-type uncertainty principles with geometric interpretation ∗

A generalisation of the classical covariance for quantum mechanical observables has previously been presented by Gibilisco, Hiai and Petz. Gibilisco and Isola has proved that the usual quantum covariance gives the sharpest inequalities for the determinants of covariance matrices. We introduce a new generalisation of the classical covariance which gives better inequalities than the classical one furthermore it has a direct geometric interpretation.

Evaluation of meteorological and epidemiological characteristics of fatal pulmonary embolism

The objective of the present study was to identify risk factors among epidemiological factors and meteorological conditions in connection with fatal pulmonary embolism. Information was collected from forensic autopsy records in sudden unexpected death cases where pulmonary embolism was the exact cause of death between 2001 and 2010 in Budapest. Meteorological parameters were detected during the investigated period. Gender, age, manner of death, cause of death, place of death, post-mortem pathomorphological changes and daily meteorological conditions (i.e. daily mean temperature and atmospheric pressure) were examined. We detected that the number of registered pulmonary embolism (No 467, 211 male) follows power law in time regardless of the manner of death. We first described that the number of registered fatal pulmonary embolism up to the nth day can be expressed as Y(n) = α ⋅ nβ where Y denotes the number of fatal pulmonary embolisms up to the nth day and α > 0 and β > 1 are model parameters. We found that there is a definite link between the cold temperature and the increasing incidence of fatal pulmonary embolism. Cold temperature and the change of air pressure appear to be predisposing factors for fatal pulmonary embolism. Meteorological parameters should have provided additional information about the predisposing factors of thromboembolism.