Aquatic plants (macrophytes) are important components of freshwater ecosystems and serve numerous purposes, physical and biological, that help to structure aquatic communities. Although macrophytes represent an essential component of stable aquatic communities, invasive macrophytes may negatively alter ecosystem properties. Non-native, invasive species have been identified as a major cause of biodiversity loss and the increasing prevalence of invasive species has prompted studies to help understand their impacts and to conserve biodiversity. Studying mechanisms of invasion also gives insight into how communities are structured and assembled. This study examined mechanisms that contribute to macrophyte invasion. First, I reviewed literature concerning mechanisms of macrophyte invasion. Mechanisms identified with this review were then placed within the context of the invasion process and potential taxonomic biases were discussed. Second, a set of classic invasion hypotheses were tested, including biotic resistance, disturbance, and stress, using mixed-effects models on survey data collected from twenty-nine lakes across the United States. Finally, using the same survey data, I performed an observational test of Darwin’s Naturalization Hypothesis at a small (point) and large (lake) scale for two highly invasive macrophytes, Potamogeton crispus and Myriophyllum spicatum. Results of the first study indicated that many invasion mechanisms have been tested with fully aquatic macrophytes with varied levels of support. In addition, there is likely a taxonomic bias depending on geographic location of the invaded area. The second study indicated that biotic interaction, disturbance, and stress interact, often in non-linear ways to influence probability of an invasive species occurring at a location. However, models containing these variables explained a relatively low percentage of variation in probabilities. Finally, there was no support for Darwin’s naturalization hypothesis at either a point or lake scale. Future research should continue the search for mechanisms that allow introduced species to establish. It is likely that general principles do not exist, at least among comparisons across ecosystem types. However, ecologists should continue to search for general patterns within definable ecosystem units to increase understanding about factors contributing to invasibility.

Biological invasions are a significant area of research due to perceived negative environmental and economic impacts. The study of biological invasions has identified three broad components involved in successful invasions: propagule pressure, abiotic and biotic conditions. Propagule pressure is the product of introduced propagules and the frequency of those introductions, and is considered a driver in all stages of invasion. Data to quantify propagule pressure is often unavailable, and therefore, this research approached genetic information to produce estimates of propagule pressure in the successful invasion of cogongrass (Imperata cylindrica) in the United States. The following research utilized molecular methodologies to estimate genetic diversity and to infer historical introductions. Population genetic analyses were conducted for the purpose of estimating extant population-level genetic diversity at multiple-scales to first address documented cogongrass introduction(s) into this country, followed by an exploration of substantial range expansion into seven states across the region. Lastly, this research explicitly seeks evidence to support interspecific hybridization between cogongrass and a co-occurring congeneric (Imperata brasiliensis) having occurred. Aggressive range expansion by cogongrass has been attributed to such a hybridization event, but has not yet been specifically tested. Historical accounts of foreign introduction of cogongrass propagules identify two separate introductions of distinct source material made into Mississippi and Alabama. Localized population genetic analysis of these two states found substantial genetic variability within and among cogongrass populations, and supported a two-introduction scenario of distinct genetic source propagules establishing and subsequently intermixing. Enlarging the geographic scale of study incorporated five additional U.S. states currently experiencing and managing cogongrass invasion. Considerable genetic variability was found within and among the seven states surveyed. It was found that range expansion was unequal across the range, and that the most distant states tested were not genetically isolated from source populations, suggesting a possible anthropogenic role. Focusing solely on Florida where two congeners overlap ranges, morphology, and ecology, this population genetic analysis failed to detect significant evidence to support interspecific hybridization. Collectively, these investigations explored genome-level dynamics during invasion by a noteworthy invasive grass in an effort to better understand the process of biological invasions.

Crohn’s disease (CD) is an inflammatory disease of the gastrointestinal tract attributed to an aberrant immune response to environmental and microbial triggers. Individuals with CD exhibit an enrichment of pro-inflammatory strains of Adherent-Invasive E. coli (AIEC) and often report a relapse of symptoms following a period of acute psychological stress. Despite a known immunosuppressive role, the mechanism by which stress contributes toward the development and progression of intestinal inflammation remains unknown. Here, we use a well characterized model of restraint stress to investigate the influence of psychological stress on host protection against a CD-associated strain of AIEC. We found that stress results in profound intestinal dysbiosis, allowing for a complete dominance of Enterobacteriaceae. Interestingly, while stress alone drives a state of low-grade inflammation and loss of barrier integrity in the gut, in the presence of a pathobiont strain of AIEC, stress drives a substantially heightened inflammatory response which exacerbated the resultant loss of barrier integrity. Moreover, we have found stress induces an augmented nutritional immune response, providing AIEC a competitive niche against commensal bacteria lacking alternative methods of iron uptake. Further, we see that stress-induced glucocorticoids mediate broad apoptosis of the CD45+CD90+ lymphocytic population in the gut. The loss of this population prevents an appropriate IL-22 mediated response to dysbiosis. Accordingly, blocking glucocorticoid signalling or exogenous administration of IL-22 prevents the stress-induced expansion of AIEC. This work underscores the complex nature of psychological stress such that the combination of iron limitation and glucocorticoid mediated immune attrition are simultaneously required for the stress-induced expansion of AIEC. These findings present novel insight into the mechanistic consequences of glucocorticoid signalling on impaired immune function and the provision of an inflammatory environment, resulting in a distinct impact on CD susceptibility. As such, deeper insight regarding the complex underpinnings of CD will assist in efforts to design representative models and will strengthen the discovery of targeted therapeutics. / Thesis / Master of Science (MSc) / Crohn’s disease (CD) is an inflammatory disease of the gastrointestinal tract resulting from an exaggerated immune response. CD patients often report a relapse of symptoms following a period of psychological stress and are at an increased likelihood of having pro-inflammatory strains of E. coli within their gut. Here, we use a model of restraint stress to investigate how psychological stress modulates the abundance of bacterial species associated with CD. We found stress results in the limitation of essential nutrients, allowing for an outgrowth of E. coli. Further, stress hormones lead to the loss of a protective immune response in which E. coli expansion can be prevented by blocking these hormones or restoring immune signalling. Together, we conclude that stress leads to immune cell death and creates an iron limited environment that favours E. coli expansion. Such work begins to uncover the functional consequence of stress and its’ role in disease progression.

Zusammenfassung: Fentanyl und Sufentanil sind zwei synthetisch hergestellte Opioide, die in der Anästhesiologie für die intraoperative Analgesie eingesetzt werden. Sie weisen ein unterschiedliches pharmakodynamisches Profil auf. Im Jahr 2014 wurde das Opioidregime für minimal-invasive Standardeingriffe im Klinikum Fulda von Fentanyl auf Sufentanil umgestellt. In der geplanten retrospektiven Datenerhebung sollten Daten von Patienten, die vor 2014 mit Fentanyl analgesiert wurden, verglichen werden mit Daten von Patienten, bei denen nach 2014 Sufentanil in die Narkoseführung implementiert war. Untersucht werden sollte, ob der Wechsel auf ein Opioid mit einem vermeintlich geeigneteren Profil für die Narkoseführung tatsächlich die kalkulierten Vorteile erbracht hat. Die retrospektive Datenerhebung sollte aufzeigen, ob Patienten während und nach MIC-CHE oder MIC-TEP von einer Sufentanil-Gabe gegenüber der Fentanyl-Gabe profitieren: Verkürzt sich die Ausleitungsphase, haben die Patienten bei Ankunft im Aufwachraum (AWR) eine bessere Oxygenierung und/oder eine stabilere Kreislaufsituation? Leiden die Patienten nach Sufentanil unter weniger postoperativer Übelkeit und Erbrechen (PONV), benötigen sie weniger Schmerzmittel? Die Untersuchung sollte zudem klären, ob biometrische Faktoren wie Geschlecht, Alter, Gewicht und BMI in Zusammenhang mit dem eingesetzten Opioid eine relevante Rolle für das postoperative Befinden der Patienten spielten, und ob sich aus der Umstellung von Fentanyl auf Sufentanil ökonomische Vorteile ergaben. Ergebnis: Kombination Desfluran mit Sufentanil für alle untersuchten Gruppen von klinischem Vorteil. Bevorzugter Einsatz bei MIC-Eingriffen in der Allgemein- und Viszeralchirurgie empfehlenswert. - Geringerer postoperativer Schmerzmittelbedarf - Bessere postoperative Oxygenierung - Kürzere postoperative Aufwachzeit - Niedrigerer intraoperativer Opioidbedarf - Wirtschaftlich/ökonomische Gleichwert Begründete Aussage, dass Sufentanil bei MIC-Eingriffen in der Allgemein- und Viszeralchirurgie im Vergleich zu Fentanyl das überlegene Medikament ist. (überwiegend statistisch signifikant) Steigerung dieses Effekts über die Kombination mit Desfluran möglich. / Summary: Fentanyl and sufentanil are two synthetically produced opioids that are used in anesthesiology for intraoperative analgesia. They have a different pharmacodynamic profile. In 2014, the opioid regime for minimally invasive standard interventions at the clinic in Fulda was changed from fentanyl to sufentanil. In the planned retrospective data collection, data from patients who were analgesized with fentanyl before 2014 should be compared with data from patients in whom sufentanil was implemented in anesthesia after 2014. It should be investigated whether the change to an opioid with a supposedly more suitable profile for anesthesia has actually produced the calculated benefits. The retrospective data collection should show whether patients benefit from administration of sufentanil compared to administration of fentanyl during and after MIC-CHE or MIC-TEP: Shorter elimination phase? Better oxygenation-situation on arrival in the recovery room or a more stable circulatory situation? Do the patients suffer less postoperative nausea and vomiting (PONV) after sufentanil, do they need less pain-medication? The investigation should also clarify whether biometric factors such as gender, age, weight and BMI in connection with the opioid used to play an important role in the postoperative condition of the examined patients and whether there were any economic benefits in switching from fentanyl to sufentanil. Result: The combination of desflurane with sufentanil was of clinical advantage for all examined groups. Recommended for use in MIC- operations in visceral surgery. - Less need for post-operative pain medication - Better post-operative oxygenation - Shorter post-operative wake-up time - Lower intraoperative opioid requirement - Economic / economic equivalence Well-founded statement that sufentanil is the superior drug compared to fentanyl in MIC-procedures in visceral surgery. (mostly statistically significant) This effect can be increased by combining it with desflurane.

Hintergrund: Die vorgestellten Daten demonstrieren das klinische Ergebnis von Patienten, die sich eine Hüfttotalendoprothese (THA) unterzogen haben. Als Zugangsweg wurde der minimal-invasive, direkt anteriore Zugang in Einzelschnitttechnik gewählt (MIS-DAA). Die Patientin wurden bis zwölf Monate nach Operation beobachtet. Methoden: Es wurden die Daten von 73 Probanden mittels der folgenden Fragebogen ausgewertet: Harris Hip Score (HHS), eXtra Short Musculoskeletal Functional Assessment questionnaire (XSFMA), Short Form 36 (SF-36) health survey und Patient Health Questionaire 9 „deutsch“ (PHQ-9 D). Zur Schmerzmessung kam eine visuelle Analogskala (VAS von 0-4) zum Einsatz. Daneben wurde die Aktivität mit Hilfe des Schrittzählers Stepwatch™ Activity Monitor (SAM) und eines 25m Gehtests auf Zeit (T25-FW) erfasst. Während der gesamten Aufzeichnung wurden auch Komplikationen erfasst. Ergebnisse: Zwölf Monate nach der Operation verbesserten sich die HHS-Werte signifikant von 55,2 präoperativ auf 92,4 (Werte 0 – 100). Der FSFMA Funktionsscore fiel ebenfalls signifikant von 39,4 auf 10,3 und der Beeintrachtigungsscore von 47,0 auf 15,8. Der Score für die Physis (PCS) stieg im SF 36 signifikant von 27,5 präoperativ auf 47,5 nach zwölf Monaten. Der Score für mentale Gesundheit (MCS) fiel dagegen sogar leicht von 57,6 auf 55,0. Dagegen fiel die Prävalenz der mittels PHQ-9 D gemessenen Somatisierungsstörungen von elf auf einen Fall. Die Schmerzreduktion durch die Operation zeigte sich durch einen Rückgang auf der VAS von 2,41 auf 0,35 zwölf Monate postoperativ. Die durchschnittlich täglich absolvierten Lastwechsel nahmen laut Schrittzählermessung signifikant von 5113 präoperativ auf 6402 zu. Außerdem stieg die Gehgeschwindigkeit im T25-FW signifikant von 22,06 s (= 1,13 m/s) auf 18,14 s (= 1,38 m/s). Es wurden keine schwerwiegenden Komplikationen, wie z.B. Transplantatlockerungen, festgestellt. Zusammenfassung: In der Zusammenschau der Ergebnisse zeigt sich ein Jahr nach MIS-DAA-THA, dass die Patienten eine signifikant bessere Funktion, Aktivität und weniger Schmerzen aufweisen. Der MIS-DA-Zugang ist sicher und weist keine erhöhte Komplikationsrate auf. / Background: The presented data show the clinical outcome of patients undergoing total hip arthroplasty (THA) using a minimally invasive single-incision direct anterior approach (MIS-DAA) up to twelve months after surgery. Methods: The data of 73 arthroplasties were evaluated using the following questionaires: Harris Hip Score (HHS), extra short musculoskeletal functional assessment questionnaire (XSFMA), Short Form 36 (SF-36) health survey and the Patient Health Questionaire 9 „german“ (PHQ-9 D). A visual analogue scale (VAS from 0-4) was used zu measure pain. Additionally all patients activity was monitored utilizing a Stepwatch™ Activity Monitor (SAM), and a timed 25 m foot walk (T25-FW). Also complications were monitored for the entire 12 months. Results: Twelve months after surgery the HHS Score increased significantly from 55.2 preoperatively to 92.4 (out of 100). XSFMA functional index scores droped from 39.4 to 10.3 while the bother went down form 47.0 to a score of 15.8. Both scores showing a significant improvement. The SF-36 physical component score (PCS) was 27.5 ahead of the operation and did rise significantly up to 47.5 twelve months later, while the mental component score (MCS) dropped slightly, but significantly from 57,6 to 55.0. In opposition the PHQ-9 D showed a decline oft he prevalence of somatic disorders from elven cases pre-OP to one afterwards. Pain was significantly reduced by the operation, showing values dropping from 2.41 to 0.35 on a visual analogue scale (VAS).The mean cycles per day rose significantly up to twelve months after arthroplasty from 5113 of 6402 cycles per day. Furthermore, the obtained outcome for the T25-FW showed a significant increase in walking speed from 22.06 s (=1.13m/s) to 18.14 s (= 1.38 m/s). The were no severe complications, e.g. loosening of the implant, to be found. Conclusion: In summary the outcomes show that 1 year after MIS-DAA-THA patients show a significantly better function, activity and reduction of pain. The MIS-DAA is safe and shows no increased signs of complications.

Methods of non-invasive vascular imaging of thoracic vessels are briefly introducted in the first part of the thesis. Benefits and limitations of CT angiography and MR angiography of the thoracic aorta, pulmonary vessels, great thoracic veins and cardiac vessels are discussed. The main part of the thesis is concerning to pulmonary veins imaging in cohort of patients with atrial fibrilation, who underwent radiofrequency ablation of the pulmonary veins. Aim of the study was to confirm the CT angiography as suitable method of pulmonary veins imaging, to find out frequency of atypical pulmonary veins anatomic arrangement and to measure pulmonary veins diameter in our cohort, including comparison between both sexes. The main purpose of the study was to compare the diameter of pumonary veins before and after the radiofrequency ablation and discover frequency and severity of iatrogenic pulmonary vein stenoses after the procedure. The group of patients planned for biventricular stimulation implantation is presented finally. CT angiography of coronary sinus and his branches was performed before the procedure. Aim of this work was to evaluate whether the CT angiography is proper method for cardiac venous system visualisation and wheather is it possible to choose patients suitable for implantation of left ventricle...

Invasive plant species are an increasing global threat to native biodiversity. Effective management depends on accurate predictions of their spread. However, modelling the geographic distribution of invasive species, particularly with methods like correlative species distribution models (SDMs), is challenging. SDMs operate under the assumption that species are in equilibrium with their environment (i.e., they occur in all suitable environments); this assumption is more likely to be violated for a species that is still in the process of colonizing suitable environments. SDMs also assume that environmental constraints are the most important factors determining a species' distribution. However, these assumptions are not commonly assessed, and when violated can have consequences for model reliability. I investigated SDM performance and equilibrium in the invasive Vincetoxicum rossicum vine in northeastern North America. Vincetoxicum rossicum has a long, detailed history of occurrence records in its invaded range, which enabled me to observe trends in equilibrium and model performance over a relatively long time scale. I tested the hypotheses that: 1) invasive species approach equilibrium in environmental and geographic space over time; 2) SDM performance will increase as V. rossicum approaches environmental equilibrium; and 3) range expansion in the early stages of an invasion is primarily a function of dispersal rather than environmental constraints, while the reverse is true in later stages. I found that V. rossicum has reached equilibrium in environmental space, but is still expanding its geographic range. SDM performance was poor in the first 30 years following introduction, but then improved as V. rossicum approached environmental equilibrium. SDMs were outperformed by spatial dispersal models in the earliest time period, however, the reverse was true for all subsequent time periods. Overall, these results suggest that V. rossicum’s distribution is becoming more stable and more predictable over time and that models built using the most recent data for this species, will be the most transferable across time and space. Additionally, my findings highlight the need for researchers modelling invasive species’ distributions to consider the inherent assumptions, biases, and unique features related to SDMs and SDMs of invasive species.

No description available.

Twenty-first-century globalization has led to an extraordinary rise in international trade and transit. Consequentially, invertebrates, plants, and mammals are displaced more frequently, which has catalyzed a historic rise in biological invasions. The Joro Spider (Araneae: Trichonephila clavata) recently established from Asia in a landlocked region of southern Appalachia. Its range continues to expand; its cold tolerance is expected to favor northward invasion. As a large-bodied orbweaver that forms extensive webs and aggregations, the Joro spider is likely capable of inducing fundamental change to community structure via spatial competition. A valuable first step in estimating any invader’s economic or biological impact is to hypothesize regions susceptible to invasion using species distribution models. Recent work also shows that comparing global and regional distribution models yields insight into different stages of invasion. To examine potential spread and niche utilization differences in the Joro spider, one global and two regional models were developed. Maximum Entropy models were trained using open-source citizen science occurrence data and six bioclimatic variables at 2.5-arcminute resolution. An AUC-weighted ensemble model was used to produce each of the 3 global suitability projections. To compare invasive stage differences, projections were then translated to presence-absence maps using a 50% suitability threshold. The Asia-regional model predicts widespread suitability in eastern North America. However, the US-regional model reflects local adaptation to a climate niche that does not occur in the spider’s historic Asian range. Permutation feature importance shows the US-regional model was driven mainly by precipitation seasonality (64%) and annual oscillations in daily temperature range (29.1%). The Asia-regional model was instead driven by mean temperature of the driest quarter (34.9%), maximum temperature of the warmest month (23.6%), and precipitation of the warmest quarter (20.1%). The introduced Joro spider has invaded a North American niche that it is naïve to, but which co-occurs spatially with a niche akin to its historic Asian niche. If the Asia-regional climatic niche is indeed exploitable in North America, then conservative estimates show the bounds of range suitability should approach the 95th meridian and the 28th and 50th parallels. A total of 1,231,711 km2 within North America was predicted above 50% suitability. Altogether, these findings suggest niche versatility and plentiful suitable habitat favors successful North American invasion by the Joro spider.

The United States has an abundant stock of naturalized wild growing bamboo species that are generally considered invasive. This project explores the use of locally harvested, so called “invasive” bamboo as a potential building material incorporated into a modular, kit-of-parts style construction system. These structures are uniquely suited to address the need for expanded spaces and extensions that bridge between the strictly indoor vs. outdoor distinction of existing buildings, as revealed by the Covid-19 pandemic. The rhizomatic mechanism of spread that is characteristic of bamboo species is used as the framework to propose a tectonic system that is decentralized, adaptable, and deployable. Drawing on a series of formal explorations, this system is further developed through a case study proof of concept design for Morningside Elementary School in Atlanta, GA, by supplementing, expanding, and adapting the existing facilities for eating, gathering, recreation, and learning to address the requirements of a Covid-19 safe school environment and to propose an ongoing outdoor learning program.