Studium fyzikálních vlastností nových materiálů a nanostruktur pro spinovou fotoniku a elektroniku

Tato práce je věnovaná studii dvou magnetických materiálů. Byly zkoumány tenké vrstvy ferrimagnetické slitiny GdxFe100−x vyrobené pomocí magnetronového naprašování s různým složením blízko kompenzační teploty x . = 25 na Si sub- strátu s použitím Ru a SiO2 krycích vrstev. Měření magnetooptické Ker- rovy spektroskopie a magnetometrie ukázaly opačné znaménko magnetizace při překročení složení nad kompenzační teplotu, stejně tak jako zesílení jevu pro vzorky s SiO2 krycí vrstvu. Spektroskopická elipsometrie odhalila komplexní diagonální člen tenzoru permitivity. Byl proveden pokus přípravy tenké vrstvy ferromagnetického tetragonálního D022 − Mn3Ge. To bylo provedeno nejprve kalibrací Mn a Ge terčů v magnetronové naprašovačce a poté současnou de- pozicí prvků na MgO (001) substrát s Cr vyrovnávací vrstvou. 1This work is dedicated to the study of two magnetic materials. Thin films of ferrimagnetic alloy GdxFe100−x fabricated with different compositions near the compensation temperature x . = 25 by magnetron sputtering on Si substrate with the usage of Ru and SiO2 capping layer were investigated. Measure- ments of the magneto-optic Kerr effect spectroscopy and magnetometry showed opposite signs in magnetization when the compensation temperature composi- tion exceeded as well as the enhancement of the effect for SiO2 capping layer. Spectroscopic ellipsometry revealed the complex diagonal element of the per- mittivity tensor. An attempt to prepare thin film of ferromagnetic tetragonal D022 − Mn3Ge was made. That was done firstly by calibrating Mn and Ge targets in magnetron sputtering machine and secondly simultaneous deposition of the elements on MgO (001) substrate with Cr buffer layer. 1Fyzikální ústav UKInstitute of Physics of Charles UniversityMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

Tool for Writing and Progress Tracking of Technical Report

Táto bakalárska práca sa zaoberá návrhom, implementáciou a testovaním modernej webovej aplikácie, ktorá umožňuje priebežné písanie technickej správy a sledovanie procesu jej tvorby. Učiteľ definuje štruktúru práce, ktorú študentovi sprístupní. Študent priebežne píše správu a zaznamenajú sa štatistické údaje o jeho práci, ktoré systém zobrazuje na motiváciu a inšpiráciu. The bachelor thesis describes the design, implementation and testing of modern web app- lication which allows continual writing of technical documentation and following the whole creation process. A teacher de nes the structure of the project and makes it accessible to students. The student continually writes the documentation. The process will be recorded by the system and the statistics will be displayed to students and administrators for their motivation and inspiration. 

Learning Physics from Data: a Thermodynamic Interpretation

Experimental data bases are typically very large and high dimensional. To learn from them requires to recognize important features (a pattern), often present at scales different to that of the recorded data. Following the experience collected in statistical mechanics and thermodynamics, the process of recognizing the pattern (the learning process) can be seen as a dissipative time evolution driven by entropy from a detailed level of description to less detailed. This is the way thermodynamics enters machine learning. On the other hand, reversible (typically Hamiltonian) evolution is propagation within the levels of description, that is also to be recognized. This is how Poisson geometry enters machine learning. Learning to handle free surface liquids and damped rigid body rotation serves as an illustration.Comment: Submitted to the proceedings of the Les Houches Summer Schoo

Direct Poisson neural networks: learning non-symplectic mechanical systems

ABSTRACT: In this paper, we present neural networks learning mechanical systems that are both symplectic (for instance particle mechanics) and non-symplectic (for instance rotating rigid body). Mechanical systems have Hamiltonian evolution, which consists of two building blocks: a Poisson bracket and an energy functional. We feed a set of snapshots of a Hamiltonian system to our neural network models which then find both the two building blocks. In particular, the models distinguish between symplectic systems (with non-degenerate Poisson brackets) and non-symplectic systems (degenerate brackets). In contrast with earlier works, our approach does not assume any further a priori information about the dynamics except its Hamiltonianity, and it returns Poisson brackets that satisfy Jacobi identity. Finally, the models indicate whether a system of equations is Hamiltonian or not

Distinct Host–Mycobacterial Pathogen Interactions between Resistant Adult and Tolerant Tadpole Life Stages of Xenopus laevis

Mycobacterium marinum is a promiscuous pathogen infecting many vertebrates, including humans, whose persistent infections are problematic for aquaculture and public health. Among unsettled aspects of host–pathogen interactions, the respective roles of conventional and innate-like T (iT) cells in host defenses against M. marinum remain unclear. In this study, we developed an infection model system in the amphibian Xenopus laevis to study host responses to M. marinum at two distinct life stages, tadpole and adult. Adult frogs possess efficient conventional T cell–mediated immunity, whereas tadpoles predominantly rely on iT cells. We hypothesized that tadpoles are more susceptible and elicit weaker immune responses to M. marinum than adults. However, our results show that, although anti–M. marinum immune responses between tadpoles and adults are different, tadpoles are as resistant to M. marinum inoculation as adult frogs. M. marinum inoculation triggered a robust proinflammatory CD8+ T cell response in adults, whereas tadpoles elicited only a noninflammatory CD8 negative- and iT cell–mediated response. Furthermore, adult anti–M. marinum responses induced active granuloma formation with abundant T cell infiltration and were associated with significantly reduced M. marinum loads. This is reminiscent of local CD8+ T cell response in lung granulomas of human tuberculosis patients. In contrast, tadpoles rarely exhibited granulomas and tolerated persistent M. marinum accumulation. Gene expression profiling confirmed poor tadpole CD8+ T cell response, contrasting with the marked increase in transcript levels of the anti–M. marinum invariant TCR rearrangement (iVα45-Jα1.14) and of CD4. These data provide novel insights into the critical roles of iT cells in vertebrate antimycobacterial immune response and tolerance to pathogens

TetR-Based Gene Regulation Systems for Francisella tularensis

ABSTRACT There are a number of genetic tools available for studying Francisella tularensis , the etiological agent of tularemia; however, there is no effective inducible or repressible gene expression system. Here, we describe inducible and repressible gene expression systems for F. tularensis based on the Tet repressor, TetR. For the inducible system, a tet operator sequence was cloned into a modified F. tularensis groESL promoter sequence and carried in a plasmid that constitutively expressed TetR. To monitor regulation the luminescence operon, luxCDABE , was cloned under the hybrid Francisella tetracycline-regulated promoter ( FTRp ), and transcription was initiated with addition of anhydrotetracycline (ATc), which binds TetR and alleviates TetR association with tetO. Expression levels measured by luminescence correlated with ATc inducer concentrations ranging from 20 to 250 ng ml −1 . In the absence of ATc, luminescence was below the level of detection. The inducible system was also functional during the infection of J774A.1 macrophages, as determined by both luminescence and rescue of a mutant strain with an intracellular growth defect. The repressible system consists of FTRp regulated by a reverse TetR mutant (revTetR), TetR r1.7. Using this system with the lux reporter, the addition of ATc resulted in decreased luminescence, while in the absence of ATc the level of luminescence was not significantly different from that of a construct lacking TetR r1.7. Utilizing both systems, the essentiality of SecA, the protein translocase ATPase, was confirmed, establishing that they can effectively regulate gene expression. These two systems will be invaluable in exploring F. tularensis protein function

Experimental and computational study on mechanical stabilisation of sacral bone injuries

The experimental study focuses on minimally invasive fixation techniques of linear sacral fractures and its results are utilised for development and validation of the related computational model. The model is extended for analysis of unstable pelvic ring injuries with spinopelvic dissociation and their treatment with lumbo-sacral fixation techniques. Influence of a cross-link transverse connector and of an additional iliosacral screw on the fixation stability is assessed

Prognostic factors for abatacept retention in patients who received at least one prior biologic agent: an interim analysis from the observational, prospective ACTION study

Background: The emergence of new therapies for the treatment of rheumatoid arthritis (RA), the paucity of head-to-head studies, and the heterogeneous nature of responses to current biologics highlight the need for the identification of prognostic factors for treatment response and retention in clinical practice. Prognostic factors for patient retention have not been explored thoroughly despite data for abatacept and other biologics being available from national registries. Real-world data from the ACTION study may supplement the findings of randomized controlled trials and show how abatacept is used in clinical practice. The aim of this interim analysis was to identify prognostic factors for abatacept retention in patients with RA who received at least one prior biologic agent. Methods: A large, international, non-interventional cohort of patients with moderate-to-severe RA who initiated intravenous abatacept in Canada and Europe (May 2008–January 2011) enrolled in the ACTION study. Potential prognostic factors for retention in this interim analysis (data cut-off February 2012; including patients from Canada, Germany, Greece, and Italy) were baseline demographics and disease characteristics, medical history, and previous and concomitant medication. Clinically relevant variables with p ≤ 0.20 in univariate analysis and no collinearity were entered into a Cox proportional hazards regression model, adjusted for clustered data. Variables with p ≤ 0.10 were retained in the final model (backward selection). Results: The multivariate model included 834 patients. Anti-cyclic citrullinated peptide (CCP) antibody positivity (hazard ratio [95 % confidence interval]: 0.55 [0.40, 0.75], p < 0.001), failure of <2 prior anti-tumor necrosis factors (TNFs) (0.71 [0.56, 0.90], p = 0.005 versus ≥2 prior anti-TNFs), and cardiovascular comorbidity at abatacept initiation (0.48 [0.28, 0.83], p = 0.009) were associated with lower risk of abatacept discontinuation. Patients in Greece and Italy were less likely to discontinue abatacept than patients in Germany and Canada (Greece: 0.30 [0.16, 0.58]; Italy: 0.50 [0.33, 0.76]; Canada: 1.04 [0.78, 1.40], p < 0.001 versus Germany). Conclusions: Real-world prognostic factors for abatacept retention include anti-CCP positivity and fewer prior anti-TNF failures. Differences in retention rates between countries may reflect differences in healthcare systems. The finding that abatacept has potential advantages in patients with cardiovascular comorbidities needs to be confirmed in further research