658 research outputs found
On a variational principle in thermodynamics
No full textThe dynamic principle is proposed that a thermodynamic system evolves in time so that the total energy balance including the energy drawn from the environment becomes stationary for all admissible variations of thermodynamic states. It is shown that this principle allows to obtain variational characterizations of contact Hamiltonian equations (even in presence of ports), reaction equations and doubly nonlinear reaction-diffusion equations. Further, examples are discussed which support this principle
Molekulare Nachweissysteme für Antibiotika-Resistenz vermittelnde Mutationen bei Mycobacterium tuberculosis
No full textEvolutionary pathways towards β-lactam resistance in Haemophilus influenzae
No full textAntimicrobial resistance is among the greatest global health threats, causing over 1.2 million deaths annually, with projections of 10 million by 2050 if not effectively addressed. Haemophilus influenzae, a WHO-designated Priority Pathogen and frequent cause of respiratory infections, increasingly shows resistance to β-lactam antibiotics such as ampicillin. Meanwhile, invasive infections including meningitis and sepsis are rising. This thesis investigates genetic mechanisms, evolutionary dynamics, and phenotypic effects of non-β-lactamase-mediated β-lactam resistance to improve diagnostics and treatment strategies. In β-lactamase-negative isolates, mutations in ftsI (encoding penicillin-binding protein 3, PBP3) are the main mechanism. A meta-analysis combined with phylogenomic and genome-wide association studies confirmed PBP3 substitution patterns linked to ampicillin and cefotaxime resistance and identified new candidate determinants, such as ompP2. Experimental evolution under selective pressure from ampicillin, cefotaxime, or ceftriaxone revealed ftsI and ompP2 mutations associated with decreased β-lactam susceptibility. Phenotypic heterogeneity was observed for specific ompP2 mutants. Furthermore, evolved mutants exhibited decreased bacterial fitness and collateral effects to other antibiotics. Finally, unstabe heteroresistance caused by a genomic inversion affecting ompP2 was identified, leading to transient ceftriaxone resistance that reverted under antibiotic-free conditions. This dynamic mechanism may evade standard diagnostics and contribute to therapeutic failure. Overall, this work provides new insights into the molecular and evolutionary basis of β-lactam resistance in H. influenzae, emphasizing the need for genome-based diagnostics and evolution-informed therapies
Globale Populationsstruktur und Evolution von Mycobacterium tuberculosis Komplex-Stämmen des Beijing-Genotyps
No full textDrug-resistance profiling and transmission dynamics of multidrug-resistant Mycobacterium tuberculosis in Saudi Arabia revealed by whole genome sequencing
No full textHawra Al-Ghafli,1,* Thomas A Kohl,2,3,* Matthias Merker,2,3,* Bright Varghese,1,* Anason Halees,4 Stefan Niemann,2,3 Sahal Al-Hajoj1 1Mycobacteriology Research Section, Department of Infection and Immunity, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia; 2Molecular and Experimental Mycobacteriology, Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Borstel 23845, Germany; 3German Centre for Infection Research (DZIF), Partner site Borstel, Borstel 38124, Germany; 4Data and Information Office, Anfas Medical Centre, Hittin District, Riyadh, Saudi Arabia *These authors contributed equally to this work Background: In Saudi Arabia, cross-border transmission of multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) strains might be particularly fostered by high immigration rates. Herein, we aimed to elucidate the transmission dynamics of MDR-MTBC strains and reveal a detailed prediction of all resistance-conferring mutations for the first- and second-line drugs.Methods: We investigated all MDR-MTBC strains collected between 2015 and 2017 from provincial mycobacteria referral laboratories and compared demographic and clinical parameters to a cohort of non-MDR-TB patients using a whole genome sequencing approach. Clusters were defined based on a maximum strain-to-strain genetic distance of five single-nucleotide polymorphisms (SNPs) as surrogate marker for recent transmission, and then investigated molecular drug-resistance markers (37 genes).Results: Forty-eight (67.6%) MDR-MTBC strains were grouped in 14 different clusters, ranging in size from two to six strains; 22.5% (16/71) of all MDR-MTBC isolates were predicted to be fully resistant to all five first-line drugs, and five strains (7.0%) exhibited fluoroquinolone resistance. Moreover, we revealed the presence of 12 compensatory mutations as well as 26 non-synonymous SNPs in the rpoC gene and non-hotspot region in rpoB, respectivelyConclusion: Optimized TB molecular surveillance, diagnosis, and patient management are urgently needed to contain MDR-MTBC transmission and prevent the development of additional drug resistance. Keywords: molecular profiling, drug resistance, genotyping, detailed prediction, compensatory mutations, drug-resistance mutation
A Lover of Sunsets
No full textPart of the Forces 2022 author and artist Publication Exhibition. Displayed from April 11-14, 2022.https://digitalcommons.collin.edu/forcesexhibition2022/1000/thumbnail.jp
Optische Kohärenztomografie im Zeit- und Frequenzbereich
No full textIn dieser Arbeit wird auf den Einfluss nicht gaußförmiger Lichtquellen und dessen Potential eingegangen. Des Weiteren wird die Entstehung von Artefakten bei Messungen an Proben mit spektraler Reflektivität und dispersiven Proben erklärt und ein möglicher Umgang damit dargelegt. Weiterhin werden Vorteile der optischen Kohärenztomografie gegenüber der Konfokalmikroskopie erläutert. Während die Konfokalmikroskopie nur über die Intensität Positionen ermittelt, werden in der OCT die Intensität und die Phase ausgewertet. Zusätzlich tragen nur kohärente Teile des Lichts zu einem Signal bei. Es wird das Potential der optischen Kohärenztomografie gegenüber herkömmlichen Methoden deutlich und die Nutzung dieser modernen Technik praxisnah erklärt
Zensur und Gleichschaltung Thüringer Zeitungen zwischen 1933 - 1993 ; Dokumentation auf der Grundlage der Tagung vom 19. Juni 1993 im Pavillon Scherfgasse, Weimar
No full textLeserens emosjonelle respons i "Kunsten å stamme uten at noen merker det" (2022) - En retorisk og affektteoretisk lesning av Lars Petter Sveens selvbiografi.
No full textI denne oppgaven gjør jeg en affektteoretisk og retorisk analyse av selvbiografien Kunsten å stamme uten at noen merker det av Lars Petter Sveen. Oppgaven undersøker de følelsesmessige grepene forfatteren tar for å påvirke leserens emosjonelle reaksjoner. Affektteori er et relativt nytt forskningsfelt innenfor litteraturen, og i denne oppgaven tar jeg for meg Suzanne Keen sitt affektteoretiske rammeverk hvor hun begrenser det affektive til den emosjonelle reaksjonen, empati. Keen gjør rede for hvordan ulike narrative og empatiske teknikker kan benyttes for å vekke empati hos den som leser, og det er nettopp dette denne oppgaven også undersøker. Den retoriske teorien blir brukt for å supplere affektteorien, og det legges derfor et særlig fokus på den retoriske appellformen patos. Det teoretiske rammeverket som presentert ovenfor blir videre anvendt for å belyse hvordan det litterære verket får frem det empatiske i leseren. Her blir analysen delt inn i ulike seksjoner hvor jeg tar for meg de aspektene jeg anser som å ha størst affektive påvirkningskraft på leseren. Funnene av analysen viser at bruken av ulike empatiske teknikker og retoriske virkemidler i Kunsten å stamme uten at noen merker det i flere tilfeller virker sammen når det kommer til å påvirke leseren til å reflektere og handle på en bestemt måte. Ulike narrative teknikker og retoriske grep har en funksjon på å fremkalle bestemte følelsesmessige reaksjoner, da de i all hovedsak bidrar til å forsterke inntrykket. De ulike grepene gir dybde i forståelsen, større muligheter for gjenkjennelse og de bidrar til å øke historiens alvor. Dette gjør at den empatiske evnen hos leseren blir berørt og beveget i positiv retning. Karakteridentifikasjon, gjenkjennelige opplevelser og følelsen av fellesskap er blant annet noe av det som anses som å ha en verdi av affektiv funksjon. Selv om de to teoriene på mange måter utfyller hverandre i flere tilfeller, viser det seg likevel at det finnes et skille mellom dem. Avslutningsvis, i en egen drøftingsdel, kaster jeg dermed et kritisk blikk over hvorvidt teoriene egnet seg i analysen og hvordan de både utfylte og var kritiske til hverandres perspektiv.In this thesis, I do an affect-theoretical and rhetorical analysis of the autobiography Kunsten å stamme uten at noen merker det by Lars Petter Sveen. The assignment examines the emotional steps the author takes to influence the reader’s emotional reactions. Affect theory is a relatively new field of research within literature, and in this thesis, I consider Suzanne Keen’s affect theory framework, where she limits the affective to the emotional reaction, empathy. Keen explains how various narrative and empathetic techniques can be used to arouse empathy in the reader, and this is precisely what this thesis also examines. The rhetorical theory is used to supplement the affect theory, and a particular focus is therefore places on the rhetorical form of appeal pathos. The theoretical framework presented above is further used to illuminate how the literary work brings out the empathetic in the reader. Here, the analysis is divided into different sections where I deal with the aspects that I consider to have the greatest affective influence on the reader. The findings of the analysis show that the use of various empathic techniques and rhetorical devices in Kunsten å stamme uten at noen merker det works together in several cases when it comes to influencing the reader to reflect and act in a certain way. Various narrative techniques and rhetorical moves have the function of evoking certain emotional reactions, as they essentially help to reinforce the impression. The different moves provide depth in understanding, greater opportunities for recognition and they help to increase the seriousness of the story. This means that the reader’s empathetic ability is touched and moves in a positive direction. Character identification, recognizable experiences and the feeling of community are, among other things, some of that is considers to have a value of affective function. Although the two theories complement each other in many ways in several cases, it still turns out that there is a difference between them. In conclusion, in a separate discussion section, I thus take a critical look at whether the theories were suitable in the analysis and how they both complemented and were critical of each other’s perspective
Metrically Thin Singularities of Integrable CR Functions
No full textIn this article, we consider metrically thin singularities E of the solutions of the tangential Cauchy-Riemann operators on a smoothly embedded Cauchy-Riemann manifold M (CR functions on M \ E). Our main result establishes the removability of E within the space of locally integrable functions on M, which are CR on M\E, under the hypothesis that the (dim M - 2)-dimensional Hausdorff volume of E is zero and that the CR-orbits of M and of M \ E are comparable. [ABSTRACT FROM AUTHOR</p
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