213 research outputs found
The benefit of atrial septal defect closure in elderly patients*
No full textMonika Komar, Tadeusz Przewlocki, Maria Olszowska, Bartosz Sobien, Piotr Podolec Department of Cardiac and Vascular Diseases, Institute of Cardiology, Jagiellonian University, Krakow, Poland Objective: Closure of an atrial septal defect in elderly patients is controversial. The aim of the study was to evaluate the outcomes of transcatheter closure of secundum atrial septal defects (ASDs) in elderly patients.Patients and methods: From a total of 488 patients with ASDs who underwent transcatheter closure, 75 patients aged over 60 years (45 female, 30 male) with a mean age of 65.3±15.7 (60–75) years were analyzed. All patients had an isolated secundum ASD with a mean pulmonary blood flow:systemic blood flow of 2.84±1.9 (1.5–3.9). Symptom-limited treadmill exercise tests with respiratory gas-exchange analysis and transthoracic color Doppler echocardiographic study, as well as quality of life measured using the Short Form (36) Health Survey (SF-36) were repeated in all patients before the procedure and after 12 months of follow-up.Results: The atrial septal device was successfully implanted in all patients (procedure time 37.7±4.5 [13–59] minutes, fluoroscopy time 11.2±9.9 [6–40] minutes). There were no major complications. The defect echo diameter was 17.7±15.8 (12–30) mm. The mean balloon-stretched diameter of ASDs was 22.4±7.9 (14–34) mm. The diameter of the implanted devices ranged from 16 to 34 mm. Significant improvement of exercise capacity was noted at 6 and 12 months after the procedure. Exercise time within 6 months of ASD closure was longer (P<0.001) compared to baseline values, and also oxygen consumption increased (P<0.001). Seven quality-of-life parameters (except mental health) improved at 12-month follow-up compared to baseline data. The mean SF-36 scale increased significantly in 66 (88%) patients, with a mean of 46.2±19.1 (5–69). As early as 1 month after the procedure, a significant decrease of the right ventricular dimension and the right atrium dimension was observed (P<0.001). The right ventricular dimension decreased in 67 patients (89.3%).Conclusion: Closure of ASDs in elderly patients caused significant clinical and hemodynamic improvement after percutaneous treatment, which was maintained during long-term follow-up, justifying this procedure in old age. Keywords: atrial septal defect, transcatheter closure, elderly, cardiopulmonary exercise test, quality of lif
Analysis of the Behavior of Foundations of Historical Buildings
No full textAbstractThe article is devoted to the analysis of the behaviour of the foundations of historic buildings. Some basic aspects of foundation engineering are discussed, with an emphasis placed on its development, applied techniques, and materials. Several different approaches and methods for the analysis of foundations of historical buildings are presented. A particular analysis has been focused on an example of a typical stone foundation from the sixteenth century. First, the calculations have been performed using the finite element method, then the bearing capacity and the settlement analysis has been determined according to EC-7. Next, the bearing capacity has been evaluated using simplified analysis. A settlement of the foundation has been also estimated using Kerisel's proposal. The information should allow for a better understanding of the behaviour of foundations discussed in this research, and especially of methods of their analysis. A comparison analysis has been performed and possible directions for further research in this field have been indicated
Photoemission yield and the electron escape depth determination in metal-oxide-semiconductor structures on N+-type and P+-type silicon substrates
No full textThis article gives a quantitative analysis of electron photoemission yield from N+-type and P+-type substrates of MOS structures. Based on this analysis, a method is presented to estimate both the scattering length, l, of electrons in the image force potential well and of photoelectron escape depth, x(esc), from the semiconductor substrate. This method was used to estimate the scattering length and the escape depth from the substrates of Al-SiO2-Si (N+-type and P+-type) structures. It was found that for N+-type substrate structures the scattering in the image force potential well has a dominating influence on the photoemission yield while for P+-type substrate structures both the scattering in the image force potential well and the photoemission from the subsurface regions of the photoemitter play important roles. It was found that the scattering length in the image force potential well was equal to l = 6.7-6.9 nm for structures on both N+ and P+ substrates, produced in the same processing conditions. For structures on P+ substrates, the escape depth was found to be equal to x(esc) = 8-9 nm. The scattering length, l, determined in this study is considerably larger than the one reported previously (l = 3.4 nm) for similar MOS structures. The escape depth x(esc) determined in this study is also considerably larger than the escape depth determined previously (x(esc) = 1.2-2.5 nm) for the external photoemission from uncovered silicon surfaces into vacuum
Study of pion production in ν_μCC interactions on O16 using different MC generators
No full textIn this report we present simulated event numbers, for various MC generators,
for pion production in CC reactions on . For the
simulation we used four different neutrino interaction generators: GENIE,
FLUKA, NEUT, and NuWro, as proposed during the 45th Karpacz Winter School on
neutrino interactions. First we give a brief outline of the theoretical models
relevant to pion production. We then present results, in the form of tables
showing the occupancy of primary and final state pion topologies, for all the
generated samples. Finally we compare the results from the different generators
and draw conclusions about the similarities and differences. For some of the
generators we explore the effect of varying the axial mass parameter or the use
of a different nuclear model
Functional characterization of MuSK, receptor tyrosine kinase required for the formation and the maintenance of nerve-muscle synapses : "in vivo" and "in vitro" approaches
No full textThe developing neuromuscular junction (NMJ) serves as one of the best model systems for studying synapse formation since changes in shape, size, and molecular composition can be followed with high spatial and temporal resolution. Formation of the NMJ depends on coordinated interactions between nerve terminals and muscle fibres [1] and requires reciprocal signals from both cells to efficiently regulate all the events taking place during its development. This includes synapse-specific gene expression, generation of action potentials and stabilization events leading to the formation of a sophisticated apparatus which ensures that the muscle fibre is provided with trophic factors as well as electrical stimuli. The receptor tyrosine kinase MuSK and its natural ligand, a neuron-specific isoform of the extracellular matrix molecule agrin, are considered to play a fundamental role in the formation and maintenance of the NMJ. In cultured myotubes, MuSK is activated by neural agrin, and this causes its phosphorylation and results in the formation of AChRs clusters on the cell surface [2-5]. The present study discusses different approaches to understand better the mechanisms of how the NMJ is formed and maintained. In the first project, we addressed the question of MuSK – neural agrin interaction and the necessity for an additional component of the agrin receptor complex. We generated transgenic mice overexpressing MuSK or neural mini-agrin as well as both proteins throughout the entire muscle fibre. We found evidence that in muscle cells MuSK is sufficient to respond to neural agrin with no necessity of any additional co-receptor protein. We also show that Dok-7, a MuSK adaptor protein, limits the formation of ectopic postsynaptic like structures in innervated muscle. From this, we conclude that it is very likely that in muscle cells MuSK serves as a functional receptor for neural agrin. The second project refers to the regulation of the NMJ formation. We found that signal transduction downstream of agrin involves the mitogen-activated protein kinase (MAPK) pathway, particularly ERK1/2 and JNK. It involves MuSK signaling, requires Dok7 and is ErbB-independent. We also show that MAPK phosphatase-1, MKP-1, plays a crucial regulatory role in formation of the nerve-muscle connection. Results of the third project describe that a miniaturized form of agrin is able to fully rescue perinatal death of agrin-deficient mice, and that this function does not depend on local deposition of agrin at synapses. Moreover, we show that acetylcholine together with neural agrin stabilizes the postsynaptic structures at the NMJ. The function of agrin in CNS was our main interest in the fourth project. Using
agrin-deficient mice with a transgenic reconstitution of the expression of neural agrin by motor neurons, we found that in the brain, agrin is localized to the excitatory synapses. Lack of agrin resulted in a strong reduction of synaptic structures in the cerebral cortex coinciding with the attenuation of the frequency of miniature postsynaptic currents. Additionally we found that muscle specific kinase MuSK is also expressed in the brain, thus possibly involved in the formation of the nerve-nerve connections. Finally, we show that agrin function involves MAP kinase signaling
Diagnostic measurements in LSI/VLSI integrated circuits production
No full textxv, 356 p. : ill. ; 23 cm
PECVD and thermal gate oxides on 3C vs. 4H SiC : Impact on leakage, traps and energy offsets
No full textEnergy-band model offsets, trap density distributions and gate leakage characteristics of MOS capacitors with PECVD and thermal gate oxides on 3C-SiC and 4H-SiC were compared. The difference in trap energy distributions between the polytypes confirmed the lesser 3C-SiC polytype vulnerability to near-interface traps (NIT), which are alternatively found in high density in the 4H-SiC. It was also shown that the quality of the PECVD oxides obtained in this experiment were comparable to that of the thermal oxide. Only a slight increase of leakage current was observed in the PECVD oxides due to oxide inhomogeneity in the lower electric field interval of the Fowler-Nordheim range. Finally, the energy band model of the SiC MOS devices was described quantitatively for different combinations of polytype and oxidation method, which illustrated the influence of technological processing on the energy offsets and potentials, and could be used for further development of the devices and processes. © The Author(s)</p
Effects of plate material properties on vibration frequency, .
No full textEffects of plate material properties on vibration frequency, .</p
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