Automated Reconstruction of Evolving Curvilinear Tree Structures

Curvilinear networks are prevalent in nature and span many different scales, ranging from micron-scale neural structures in the brain to petameter-scale dark-matter arbors binding massive galaxy clusters. Reliably reconstructing them in an automated fashion is of great value in many different scientific domains. However, it remains an open Computer Vision problem. In this thesis we focus on automatically delineating curvilinear tree structures in images of the same object of interest taken at different time instants. Unlike virtually all of the existing methods approaching the task of tree structures delineation we process all the images at once. This is useful in the more ambiguous regions and allows to reason for the tree structure that fits best to all the acquired data. We propose two methods that utilize this principle of temporal consistency to achieve results of higher quality compared to single time instant methods. The first, simpler method starts by building an overcomplete graph representation of the final solution in all time instants while simultaneously obtaining correspondences between image features across time. We then define an objective function with a temporal consistency prior and reconstruct the structures in all images at once by solving a mathematical optimization. The role of the prior is to encourage solutions where for two consecutive time instants corresponding candidate edges are either both retained or both rejected from the final solution. The second multiple time instant method uses the same overcomplete graph principle but handles the temporal consistency in a more robust way. Instead of focusing on the very local consistency of single edges of the overcomplete graph we propose a method for describing topological relationships. This favors solutions whose connectivity is consistent over time. We show that by making the temporal consistency more global we achieve additional robustness to errors in the initial features matching step, which is shared by both the approaches. In the end, this yields superior performance. Furthermore, an added benefit of both our approaches is the ability to automatically detect places where significant changes have occurred over time, which is challenging when considering large amounts of data. We also propose a simple single time instant method for delineating tree structures. It computes a Minimum Spanning Arborescence of an initial overcomplete graph and proceeds to optimally prune spurious branches. This yields results of lower but still competitive quality compared to the mathematical optimization based methods, while keeping low computational complexity. Our methods can applied to both 2D and 3D data. We demonstrate their performance in 3D on microscopy volumes of mouse brain and rat brain. We also test them in 2D on time-lapse images of a growing runner bean and aerial images of a road network

Impact of CoreValve size selection based on multi-slice computed tomography on paravalvular leak after transcatheter aortic valve implantation

Background: Paravalvular leak (PVL) has significant impact on long-term outcomes in patients after transcatheter aortic valve implantation (TAVI). This study sought to determine whether multi-slice computed tomography (MSCT)-guided valve selection reduces PVL after CoreValve implantation. Methods: The analysis encompassed 69 patients implanted with CoreValve and were divided into two groups. In Group I (30 patients), valve selection was based on standard procedures, in Group II (39 patients), on MSCT measurements. Paravalvular leak was assessed with angiography and echocardiography. Results: Multi-slice computed tomography results influenced a change of decision as to the size of the implanted valve in 12 (30.9%) patients in Group II and would have caused the decision to change in 9 (37.5%) patients in Group I. The degree of oversizing in Group I and II was 12.8% ± ± 7.6% vs. 18.6% ± 5.1% (p = 0.0006), respectively. The oversizing among the patients with leak degree of 0–1 and ≥ 2 was 18.1% ± 6.0% and 12.8% ± 7.4% (p = 0.0036). Angiographic assessment indicated post-procedural PVL ≥ 2 in 50% of patients in Group I and 20.5% in Group II (p = 0.01), while echocardiographic assessment indicated the same in 73.3% of patients in Group I and 45.6% in Group II (p = 0.0136). The composite endpoint occurred in 26.6% (8/30) patients in Group I vs. 5.1% (2/39) patients in Group II (p = 0.0118). Conclusions: Selecting the CoreValve device based on MSCT resulted in smaller rates of PVL and less frequent composite endpoint. In 1/3 of patients MSCT led to a change of the valve size. The degree of oversizing had a significant impact on PVL

Importance of radiological evaluation of global spinal balance together with lower limb alignment in planning lumbar spine deformity surgery : illustrative case presentation

BACKGROUND: The presented case illustrates the critical role of a detailed preoperative radiological evaluation in complex spine surgery. CASE REPORT: A 49-year-old patient was admitted for a revision surgery after L3–L5 fusion. Preoperative assessment showed preserved sagittal balance, coronal imbalance and valgus knee deformity. The patient reported pain of 8–10 in VAS (Visual Analogue Scale) and had an ODI (Oswestry Disability Index) of 60%. The first step of the surgery was L2–S1 fusion with decompression and spine deformity correction. The second step involved anti-valgus osteotomy of the right tibial bone. CONCLUSIONS: The assessment of global spinal balance together with lower extremity alignment should be strongly recommended

Cage Nanofillers’ Influence on Fire Hazard and Toxic Gases Emitted during Thermal Decomposition of Polyurethane Foam

Polyurethane (PUR), as an engineering polymer, is widely used in many sectors of industries. However, the high fire risks associated with PUR, including the smoke density, a high heat release rate, and the toxicity of combustion products limit its applications in many fields. This paper presents the influence of silsesquioxane fillers, alone and in a synergistic system with halogen-free flame-retardant compounds, on reducing the fire hazard of polyurethane foams. The flammability of PUR composites was determined with the use of a pyrolysis combustion flow calorimeter (PCFC) and a cone calorimeter. The flammability results were supplemented with smoke emission values obtained with the use of a smoke density chamber (SDC) and toxicometric indexes. Toxicometric indexes were determined with the use of an innovative method consisting of a thermo-balance connected to a gas analyzer with the use of a heated transfer line. The obtained test results clearly indicate that the used silsesquioxane compounds, especially in combination with organic phosphorus compounds, reduced the fire risk, as expressed by parameters such as the maximum heat release rate (HRRmax), the total heat release rate (THR), and the maximum smoke density (SDmax). The flame-retardant non-halogen system also reduced the amounts of toxic gases emitted during the decomposition of PUR, especially NOx, HCN, NH3, CO and CO2. According to the literature review, complex studies on the fire hazard of a system of POSS–phosphorus compounds in the PUR matrix have not been published yet. This article presents the complex results of studies, indicating that the POSS–phosphorous compound system can be treated as an alternative to toxic halogen flame-retardant compounds in order to decrease the fire hazard of PUR foam

The Puzzle of the La I Lines 6520.644 Å and

The strong La line 6520.644 Å is present in a Fourier Transform Spectrum (signal to noise ratio of 240), but its wavelength in commonly used tables (e.g. [1]) is given as 6520.770 Å, while in [2] the wavelength is given as 6520.74 Å, unclassified, with the remark “h ” (hazy). The line could not be classified using known energy levels of the La atom (La I) and its first ion (La II). It appears as a single broadened peak. By a combination of laser optogalvanic spectroscopy, laser-induced fluorescence and Doppler-reduced saturation spectroscopy we could introduce a new even parity La I energy level, 35449.041 cm −1, J = 13/2, with hyperfine (hf) constants A = −8.0(5) MHz, B = 10(10) MHz. For a second, up to now unknown neighbouring La I line (wavelength 6519.869 Å) we introduced another even parity energy level involved in the formation of the line, 41207.994 cm −1, J = 13/2, A = 91.6(5) MHz, B = 170(50) MHz. We tried also to explain why in old tables the wavelength given was so different

The Potential of Traditional Norwegian KVEIK Yeast for Brewing Novel Beer on the Example of Foreign Extra Stout

The development of craft brewing has spurred huge interest in unusual and traditional technologies and ingredients allowing the production of beers that would fulfil consumers’ growing demands. In this study, we evaluated the brewing performance of traditional Norwegian KVEIK yeast during the production of Foreign Extra Stout beer. The content of alcohol of the KVEIK-fermented beer was 5.11–5.58% v/v, the extract content was 5.05–6.66% w/w, and the pH value was 4.53–4.83. The KVEIK yeast was able to completely consume maltose and maltotriose. The mean concentration of glycerol in KVEIK-fermented beers was higher than in the control sample (1.51 g/L vs. 1.12 g/L, respectively). The use of KVEIK-type yeast can offer a viable method for increasing the concentration of phenolic compounds in beer and for boosting its antioxidative potential. The beers produced with KVEIK-type yeast had a total phenol content of 446.9–598.7 mg GAE/L, exhibited antioxidative potential of 0.63–1.08 mM TE/L in the DPPH• assay and 3.85–5.16 mM TE/L in the ABTS•+ assay, and showed a ferric ion reducing capacity (FRAP) of 3.54–4.14 mM TE/L. The KVEIK-fermented bears contained various levels of volatile compounds (lower or higher depending on the yeast strain) and especially of higher alcohols, such as 3-metylobutanol, 2-metylobutanol, and 1-propanol, or ethyl esters, such as ethyl acetate or decanoate, compared to the control beers. In addition, they featured a richer fruity aroma (apricot, dried fruit, apples) than the control beers fermented with a commercial US-05 strain

Laser spectroscopic characterization of the nuclear-clock isomer 229m^{229m}Th

The isotope $^{229}$Th is the only nucleus known to possess an excited state $^{229m}$Th in the energy range of a few electron volts, a transition energy typical for electrons in the valence shell of atoms, but about four orders of magnitude lower than common nuclear excitation energies. A number of applications of this unique nuclear system, which is accessible by optical methods, have been proposed. Most promising among them appears a highly precise nuclear clock that outperforms existing atomic timekeepers. Here we present the laser spectroscopic investigation of the hyperfine structure of $^{229m}$Th$^{2+}$, yielding values of fundamental nuclear properties, namely the magnetic dipole and electric quadrupole moments as well as the nuclear charge radius. After the recent direct detection of this long-searched-for isomer, our results now provide detailed insight into its nuclear structure and present a method for its non-destructive optical detection.Comment: 18 page