[Present-day policy of surgical treatment for type A acute aortic dissection]. / Sovremennaia taktika khirurgicheskogo lecheniia ostrogo rassloeniia aorty tipa A.

A surgical intervention for type A acute aortic dissection is the only effective method of treatment making it possible to prevent the development of life-threatening complications and to attain clinical recovery of the patient. Supracoronary replacement of the ascending aorta and the proximal portion of the aortic arch is considered to be the classical and most commonly used method of an open operative intervention. On the one hand, it is technically the simplest and shortest operation, and on the other, this surgical technique is often accompanied by long-term proximal and distal complications, and first of all those caused by a persistent false lumen. The accumulated surgical experience and contemporary operative techniques, as well as advances of intensive therapy in treatment of type A acute aortic dissection make it possible to currently perform more extensive primary resections in order to improve the remote results. Total aortic arch replacement, including the use of the 'frozen elephant trunk' technique leads to fast thrombosis of the false lumen, preventing progression of the disease of the thoracic aorta and promoting its positive remodelling. The article describes the perioperative therapeutic policy accepted and pursued in our medical facility, also presenting the authors' opinion on the role and place of the 'frozen elephant trunk' technique in rendering medical care for patients with type A acute aortic dissection.

Different shades of pancreatic ductal adenocarcinoma, different paths towards precision therapeutic applications.

BACKGROUND: Different histological and molecular subtypes of pancreatic ductal adenocarcinoma (PDAC), with different molecular composition and survival statistics, have recently been recognised. MATERIALS AND METHODS: This review describes the currently available studies regarding molecular and histological subtypes in PDAC. Studies from major cohorts such as International Cancer Genome Consortium as well as smaller cohorts are reviewed. We discuss where the described subtypes overlap, where the discrepancies are and which paths forward could be taken regarding diagnosis, ontogeny and therapy. RESULTS: Four molecular subtypes with strong overlap among the different studies can be found, next to a list of mixed findings. Two of the four subtypes (epithelial classical and mesenchymal basal-like) were represented in every study and were often discriminated in other solid tumours as well. These two subtypes differ substantially in prognosis. One biomarker has been discovered, only discriminating these two subtypes, and insights into subtype-specific therapeutic vulnerabilities are scarce. CONCLUSION: Subtypes can be reproducibly detected in cohorts of PDAC patients and two of them directly relate with prognosis. A consensus on the subtypes is warranted. Further discovery and validation studies are needed to identify strong biomarkers, to comprehend subtype ontogeny and to define strategies for precision medicine.

Student participation in the design of learning and teaching: Disentangling the terminology and approaches.

Background: Students are ever more involved in the design of educational practices, which is reflected in the growing body of literature about approaches to student participation. Similarities and differences between these approaches often remain vague since the terms are used interchangeably. This confusing and fragmented body of literature hampers our understanding the process and outcomes of student participation and choosing the most suitable approach for it. Method: We identified the three most frequently used terms related to the design of learning and teaching - design-based research (DBR), participatory design (PD), and co-creation - and disentangled the terminology by focusing on relevant definitions, aims, involvement of students, outcomes, and related terminology. Results: Differences between the approaches to student participation can be found in the degree to which students are the central actors and the degree to which the design is informed by educational theory. Conclusion: It is important to align the level of student participation with the purpose of the approach.

Application of open-path Fourier transform infrared spectroscopy for atmospheric monitoring of a CO2 back-production experiment at the Ketzin pilot site (Germany).

During a controlled "back-production experiment" in October 2014 at the Ketzin pilot site, formerly injected CO2 was retrieved from the storage formation and directly released to the atmosphere via a vent-off stack. Open-path Fourier transform infrared (OP FTIR) spectrometers, on-site meteorological parameter acquisition systems, and distributed CO2 point sensors monitored gas dispersion processes in the near-surface part of the atmospheric boundary layer. The test site provides a complex and challenging mosaic-like surface setting for atmospheric monitoring which can also be found at other storage sites. The main aims of the atmospheric monitoring of this experiment were (1) to quantify temporal and spatial variations in atmospheric CO2 concentrations around the emitting vent-off stack and (2) to test if and how atmospheric monitoring can cope with typical environmental and operational challenges. A low environmental risk was encountered during the whole CO2 back-production experiment. The study confirms that turbulent wind conditions favor atmospheric mixing processes and are responsible for rapid dilution of the released CO2 leading to decreased detectability at all sensors. In contrast, calm and extremely stable wind conditions (especially occurring during the night) caused an accumulation of gases in the near-ground atmospheric layer with the highest amplitudes in measured gas concentration. As an important benefit of OP FTIR spectroscopic measurements and their ability to detect multiple gas species simultaneously, emission sources could be identified to a much higher certainty. Moreover, even simulation models using simplified assumptions help to find suitable monitoring network designs and support data analysis for certain wind conditions in such a complex environment.

Technical aspects of using the 'ThoraflexTM Hybrid' prosthesis in acute type A aortic dissection. / Tekhnicheskie aspekty primeneniia proteza «ThoraflexTM Hybrid¼ pri ostrom rassloenii aorty tipa A.

The most tried out, 'classical' technique of the operation in acute type A aortic dissection is supracoronary prosthetic repair of the ascending aorta and proximal portion of the aortic arch, as the simplest and fastest intervention. However, this technique is associated with late complications related primarily to formation of a persistent false lumen leading to formation of an aneurysm of the descending aorta. Total prosthetic repair of the aortic arch, including the 'frozen elephant trunk' technique, contributes to thrombosis of the false lumen and remodelling of the thoracic aorta. The article describes peculiarities of this technique illustrated by an example of implanting the 'ThoraflexTM Hybrid' prosthesis.

Wave propagation in spatially modulated tubes.

We investigate wave propagation in rotationally symmetric tubes with a periodic spatial modulation of cross section. Using an asymptotic perturbation analysis, the governing quasi-two-dimensional reaction-diffusion equation can be reduced into a one-dimensional reaction-diffusion-advection equation. Assuming a weak perturbation by the advection term and using projection method, in a second step, an equation of motion for traveling waves within such tubes can be derived. Both methods predict properly the nonlinear dependence of the propagation velocity on the ratio of the modulation period of the geometry to the intrinsic width of the front, or pulse. As a main feature, we observe finite intervals of propagation failure of waves induced by the tube's modulation and derive an analytically tractable condition for their occurrence. For the highly diffusive limit, using the Fick-Jacobs approach, we show that wave velocities within modulated tubes are governed by an effective diffusion coefficient. Furthermore, we discuss the effects of a single bottleneck on the period of pulse trains. We observe period changes by integer fractions dependent on the bottleneck width and the period of the entering pulse train.

The frozen elephant trunk technique in acute aortic dissection: the ultimate solution? An institutional experience.

Objective: Acute aortic dissection remains a serious emergency in the field of cardiovascular medicine and a challenge for cardiothoracic surgeons. In the present study, we seek to compare the outcomes of different surgical techniques in the repair of type A acute aortic dissection. Methods: Between April 2015 and May 2023, 213 patients (82 women, aged: 63.9 ± 13.3 years) with acute aortic dissection (205 type A and 8 non-A-non-B dissections) underwent surgical treatment in our department. A total of 45 patients were treated with the frozen elephant trunk (FET) technique supported by the Thoraflex™ Hybrid prosthesis, 33 received total aortic arch replacement (TAR)-standard or conventional elephant trunk-treatment, and 135 were treated with hemiarch replacement (HR). Aortic arch surgery was performed in most patients under moderate hypothermic (28°C on average) circulatory arrest, with selective antegrade cerebral perfusion through the right axillary artery. Results: The rates of early mortality were 17.8% (38 perioperative deaths) in the whole population, 8.9% in the FET group of patients, and 33% and 17% in the TAR and HR group of patients, respectively (P-value 0.025). The rate of spinal cord injury was 2.3% (five patients), and a paresis of recurrent laryngeal occurred in 3.7% of patients (seven patients, four were treated with FET). Permanent neurological dysfunction occurred in 27 patients (12.7%). After a mean follow-up of 3 years, the rate of mid-term mortality of discharged patients was 19.4% (34 deaths: 7 FET, 4 TAR, and 23 HR) and the overall mortality rate was 33.8% [72 deaths: 11 FET (24.4%); 15 TAR (45.4%); 46 HR (34.1%)]. A total of 8 patients (17.8%) in whom FET was applied received additional endovascular treatment in the descending aorta. Conclusions: In our institutional experience, we found that the frozen elephant trunk technique with a high-end Thoraflex Hybrid prosthesis proved its surgical suitability in the treatment of acute aortic dissection with favorable outcomes. The FET technique and our perioperative management led to comparable neurological outcomes and reduced mortality rates in these emergency cases.

Hydrodynamically enforced entropic trapping of Brownian particles.

We study the transport of Brownian particles through a corrugated channel caused by a force field containing curl-free (scalar potential) and divergence-free (vector potential) parts. We develop a generalized Fick-Jacobs approach leading to an effective one-dimensional description involving the potential of mean force. As an application, the interplay of a pressure-driven flow and an oppositely oriented constant bias is considered. We show that for certain parameters, the particle diffusion is significantly suppressed via the property of hydrodynamically enforced entropic particle trapping.

Tuning the magnetic anisotropy of Co-Ni nanowires: comparison between single nanowires and nanowire arrays in hard-anodic aluminum oxide membranes.

Co(x)Ni(1-x) alloy nanowires with varying Co content (0 ≤ x ≤ 0.95), having a diameter of 130 nm and length of around 20 µm, are synthesized by template-assisted electrodeposition into the nanopores of SiO(2) conformal coated hard-anodic aluminum oxide membranes. The magneto-structural properties of both single isolated nanowires and hexagonally ordered nanowire arrays of Co-Ni alloys are systematically studied by means of magneto-optical Kerr effect magnetometry and vibrating sample magnetometry, respectively, allowing us to compare different alloy compositions and to distinguish between the magnetostatic and magnetocrystalline contributions to the effective magnetic anisotropy for each system. The excellent tunable soft magnetic properties and magnetic bistability exhibited by low Co content Co-Ni nanowires indicate that they might become the material of choice for the development of nanostructured magnetic systems and devices as an alternative to Fe-Ni alloy based systems, being chemically more robust. Furthermore, Co contents higher than 51 at.% allow us to modify the magnetic behavior of Co-rich nanowires by developing well controlled magnetocrystalline anisotropy, which is desirable for data storage applications.

Communication: impact of inertia on biased Brownian transport in confined geometries.

We consider the impact of inertia on biased Brownian motion of point-size particles in a two-dimensional channel with sinusoidally varying width. If the time scales of the problem separate, the adiabatic elimination of the transverse degrees of freedom leads to an effective description for the motion along the channel given by the potential of mean force. The possibility of such description is intimately connected with equipartition. Numerical simulations show that in the presence of external bias the equipartition may break down leading to non-monotonic dependence of mobility on external force and several other interesting effects.

A graphical model framework for decoding in the visual ERP-based BCI speller.

We present a graphical model framework for decoding in the visual ERP-based speller system. The proposed framework allows researchers to build generative models from which the decoding rules are obtained in a straightforward manner. We suggest two models for generating brain signals conditioned on the stimulus events. Both models incorporate letter frequency information but assume different dependencies between brain signals and stimulus events. For both models, we derive decoding rules and perform a discriminative training. We show on real visual speller data how decoding performance improves by incorporating letter frequency information and using a more realistic graphical model for the dependencies between the brain signals and the stimulus events. Furthermore, we discuss how the standard approach to decoding can be seen as a special case of the graphical model framework. The letter also gives more insight into the discriminative approach for decoding in the visual speller system.

Biased Brownian motion in extremely corrugated tubes.

Biased Brownian motion of point-size particles in a three-dimensional tube with varying cross-section is investigated. In the fashion of our recent work, Martens et al. [Phys. Rev. E 83, 051135 (2011)] we employ an asymptotic analysis to the stationary probability density in a geometric parameter of the tube geometry. We demonstrate that the leading order term is equivalent to the Fick-Jacobs approximation. Expression for the higher order corrections to the probability density is derived. Using this expansion orders, we obtain that in the diffusion dominated regime the average particle current equals the zeroth order Fick-Jacobs result corrected by a factor including the corrugation of the tube geometry. In particular, we demonstrate that this estimate is more accurate for extremely corrugated geometries compared with the common applied method using a spatially-dependent diffusion coefficient D(x, f) which substitutes the constant diffusion coefficient in the common Fick-Jacobs equation. The analytic findings are corroborated with the finite element calculation of a sinusoidal-shaped tube.

Mycotic aneurysm of the extracranial carotid artery: a case report and review of the literature.

Aneurysm of the extracranial carotid artery is a rare condition; mycotic aneurysms are even less common. They always need surgical treatment to prevent possible rupture, embolisation or death. The literature before 1980 mentions ligation as the only treatment for mycotic aneurysms of the carotid artery, obviously with a high morbidity and mortality rate. We describe an 85-year-old male with a left carotid artery mycotic aneurysm. He presented with a history of Transient Ischaemic Attack (TIA) four weeks after a gastrointestinal infection. Resection of the aneurysm and interposition with autologous vein was performed. Escherichia coli was isolated from the excised tissue. Primary resection of the aneurysm with autologous vein interposition, in association with prolonged antibiotic therapy, is the preferred strategy. Prompt diagnosis and aggressive treatment is essential to prevent serious complications.

Lateral parietal cortex in the generation of behavior: Implications for apathy.

A reduction in goal-directed behavior, or apathy, occurs in neurological and psychiatric disorders, though its neural substrates remain unclear. Deficits in circuits connecting the prefrontal cortex to subcortical regions are considered to underlie apathy. Although apathy is empirically associated with widespread changes in these regions, studies across disorders also link apathy with the lateral parietal cortex. Such variety in regional involvement is consistent with the established role of prefrontal and subcortical regions in models of goal-directed behavior, and with the suggestion of subtypes of apathy. However, these models do not provide a basis for the involvement of the lateral parietal cortex with apathy. Here, we review the association between lateral parietal cortex dysfunction and apathy across disorders and analyze the putative cognitive functions that may link this region with goal-directed behavior. We suggest that neural processes in the angular and supramarginal gyri of the inferior parietal lobule may provide an interface enabling the transformation of internal goals to external actions through intentional initiation of action interrelated with mechanisms of primary sensorimotor transformation. Consequently, we propose that impairment in this process of embedding intended action in a 'body schema' facilitating adequate recruitment of an effector system, is the likely mechanism underlying the association between the lateral parietal cortex and apathy. Considering the evidence, we propose a revised neurocognitive model of apathy where deficient internal initiation of behavior mediated by the inferior parietal lobule may be sufficient, though not necessary, to reduce goal-directed behavior, and may constitute a volitional subtype of apathy.

Leukocyte depletion during cardiac surgery with extracorporeal circulation in high risk patients.

BACKGROUND: Cardiopulmonary bypass is associated with systemic inflammation that may contribute to increased perioperative mortality. Depletion of circulating leukocytes may reduce the inflammatory response. We studied the effect of a leukocyte depleting filter on leukocyte activation during cardiopulmonary bypass in high risk patients. METHODS: Fifty patients undergoing coronary artery bypass grafting with a preoperative high risk were randomly placed in an arterial line leukocyte filter group (n = 25) with a leukocyte depleting filter. Blood sampling took place from the arterial line to analyze polymorphnuclear elastase and myeloperoxidase at six time points, including: A) before the induction of anesthesia, B) before the induction of the cardiopulmonary bypass C) 1 min after the release of the aorta clamp, D) the end of the operation, E) 1 h postoperative, and F) 24 h postoperative. RESULTS: Levels of polymorphonuclear elastase, (PMNE), and myeloperoxidase (MPO) were found to be higher after the release of the aortic cross clamp in the leukocyte filter group; these levels remained elevated until 24 hours after surgery and were high in comparison to preoperative baseline levels. The differences in PMNE between both groups at time points C and D (p < 0.005) and E (p < 0.05) were statistically significant. The serum levels of the S-100B and neuron specific enolase (NSE) were found to be elevated between time points C and E in both groups without statistical significance. The in-hospital mortality was 16% (4 patients) in leukocyte filter group and 4% in control group (1 patient). CONCLUSIONS: Interestingly, the activation of neutrophils was more pronounced in the LF group. The use of a leucocyte depleting filter was not advantageous for this patient cohort for clinical or biomedical endpoints.

Transition between locked and running states for dimer motion induced by periodic external driving.

We study the motion of a dimer in a one-dimensional spatially periodic washboard potential. The tilt of the latter is time-periodically modulated by an ac field. We focus interest on the detrapping of the (static) ground state solution of the dimer caused by the ac field. Moreover, we demonstrate that slow tilt modulations not only induce a trapping-detrapping transition but drive the dimer dynamics into a regime of transient long-range running states. Most strikingly, the motion proceeds then unidirectionally, so that the dimer covers huge distances regardless of the fact that the bias force in the driven system vanishes on the average. We elucidate the underlying dynamics in phase space and associate long-lasting running states with the motion in ballistic channels occurring due to stickiness to invariant tori.

Resonancelike phenomena in the mobility of a chain of nonlinear coupled oscillators in a two-dimensional periodic potential.

We study the Langevin dynamics of a two-dimensional discrete oscillator chain absorbed on a periodic substrate and subjected to an external localized point force. Going beyond the commonly used harmonic bead-spring model, we consider a nonlinear Morse interaction between the next-nearest neighbors. We focus interest on the activation of directed motion instigated by thermal fluctuations and the localized point force. In this context the local transition states are identified and the corresponding activation energies are calculated. It is found that the transport of the chain in point force direction is determined by stepwise escapes of a single unit or segments of the chain due to the existence of multiple locally stable attractors. The nonvanishing net current of the chain is quantitatively assessed by the value of the mobility of the center of mass. It turns out that the latter as a function of the ratio of the competing length scales of the system, that is the period of the substrate potential and the equilibrium distance between two chain units, shows a resonance behavior. More precisely there exists a set of optimal parameter values maximizing the mobility. Interestingly, the phenomenon of negative resistance is found, i.e., the mobility possesses a minimum at a finite value of the strength of the thermal fluctuations for a given overcritical external driving force.

Longitudinal analysis of the audiological phenotype in osteogenesis imperfecta: a follow-up study.

OBJECTIVE: This prospective study involved a longitudinal analysis of the progression of hearing thresholds in patients with osteogenesis imperfecta. METHODS: Audiometric results from 36 osteogenesis imperfecta patients (age range, 6-79 years) were compared between two test times with an average interval of 4 years. Audiometric evaluation included acoustic admittance measurements, acoustic stapedial reflex measurements, pure tone audiometry and otoacoustic emissions testing. RESULTS: Air conduction pure tone average, corrected for sex and age, and bone conduction pure tone average increased significantly in the study population (p < 0.05 and p < 0.001, respectively). In 14.3 per cent of the evaluated ears, an alteration in type and/or severity of hearing loss was observed. CONCLUSION: After an average time interval of four years, significant changes in hearing status occurred in a population of osteogenesis imperfecta patients. These findings highlight the importance of regular audiological follow up in osteogenesis imperfecta patients, including audiometry, and measurements of acoustic admittance, acoustic stapedial reflexes and otoacoustic emissions.