243 resultados para Schumacher, Gerald


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In addition to classically defined immune mechanisms, cell-intrinsic processes can restrict virus infection and have shaped virus evolution. The details of this virus-host interaction are still emerging. Following a genome-wide siRNA screen for host factors affecting replication of Semliki Forest virus (SFV), a positive-strand RNA (+RNA) virus, we found that depletion of nonsense-mediated mRNA decay (NMD) pathway components Upf1, Smg5, and Smg7 led to increased levels of viral proteins and RNA and higher titers of released virus. The inhibitory effect of NMD was stronger when virus replication efficiency was impaired by mutations or deletions in the replicase proteins. Consequently, depletion of NMD components resulted in a more than 20-fold increase in production of these attenuated viruses. These findings indicate that a cellular mRNA quality control mechanism serves as an intrinsic barrier to the translation of early viral proteins and the amplification of +RNA viruses in animal cells.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dynamik der Gewalteskalation bei kritischen Situationen am Beispiel des Fußballstadions Alain Brechbühl, Annemarie Schumacher-Dimech & Roland Seiler Institut für Sportwissenschaft, Universität Bern Schlüsselwörter: Zuschauergewalt, Wahrnehmung, Fußball, Massenveranstaltungen, Fan Einleitung Zuschauergewalt bei Fußballspielen ist in der Schweiz ein aktuelles Thema, wie etwa politische Debatten um Maßnahmen zur Prävention von Eskalationen zeigen. Während in anderen Ländern bereits verschiedene Studien durchgeführt wurden (bspw. Hylander & Granström, 2010), existiert in der Schweiz kaum Forschung zur Dynamik und den möglichen Faktoren, die den Unterschied zwischen einer Eskalation oder Nichteskalation ausmachen könnten. Insbesondere die Sicht beteiligter Personen ist dazu von entscheidender Bedeutung. Das vorliegende Projekt beschäftigt sich mit der subjektiv wahrgenommenen Gewaltsituation und deren zentralen Faktoren und Ursachen im Kontext des Fußballs. Methode Aufgrund der spärlichen Forschungslage in der Schweiz wurde eine explorative qualitative Studie mit involvierten und nichtinvolvierten Personen (Fußballfans, Sicherheitspersonal und die Polizei) durchgeführt, um Daten über kritische Situationen bei Spielen der Raiffeisen Super League zu erheben. Die ausgewählten Personen wurden einzeln mit narrativen Interviews zu der erlebten Situation befragt um genauere Erkenntnisse zur Situation zu erhalten. Zu vier Situationen wurden 34 Interviews durchgeführt (12 mit Polizeiangehörigen, 11 mit Fans, 9 mit Fanarbeitern und 2 mit Sicherheitsarbeitern). Die Auswertung erfolgte mit der interpretativen phänomenologischen Analyse. Ergebnisse Es zeigten sich individuelle und gruppenspezifische Wahrnehmungen in kritischen Situationen. Bei den befragten Personen herrschte häufig eine Tendenz zur (negativen) Stereotypisierung der gegenüberstehenden Gruppenmitglieder. Schnelle und klare Kommunikation, genügend Distanz zwischen den Gruppen und das Entfernen von gruppenspezifisch bedrohlichen Hinweisreizen (bspw. Polizei-Rüstungen) konnten als relevante Faktoren für gewaltfreie Lösungen festgestellt werden. Diskussion Die vorliegenden Ergebnisse sprechen für die Aufrechterhaltung einer differenzierten Betrachtungsweise und das Beiziehen von Vermittlungspersonen (von Fan- wie auch Polizeiseite) in kritischen Situationen, um Eskalationen vermeiden zu können. Es zeigen sich Ähnlichkeiten zu den Ergebnissen von Hylander & Granström (2010). Es werden noch weitere kritische Situationen analysiert, um konkrete Praxisempfehlungen zu formulieren. Literatur Hylander, I., & Granström, K. (2010). Organizing for a peaceful crowd: an example of a football match. Fo-rum Qualitative Social Research, 11 (2), Zugriff am 22.01.2014 unter http://www.qualitative-research.net/index.php/fqs/article/view/1462/2969.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coumarins are extensively studied anticoagulants that exert additional effects such as anticancerogenic and even anti-inflammatory. In order to find new drugs with anticancer activities, we report here the synthesis and the structural analysis of new coumarin derivatives which combine the coumarin core and five member heterocycles in hydrazinylidene-chroman-2,4-diones. The derivatives were prepared by derivatization of the appropriate heterocyclic amines which were used as electrophiles to attack the coumarin ring. The structures were characterized by spectroscopic techniques including IR, NMR, 2D-NMR and MS. These derivatives were further characterized especially in terms of a potential cytotoxic and apoptogenic effect in several cancer cell lines including the breast and prostate cancer cell lines MCF-7, MDA-MB-231, PC-3, LNCaP, and the monocytic leukemia cell line U937. Cell viability was determined after 48 h and 72 h of treatment with the novel compounds by MTT assay and the 50% inhibitory concentrations (EC50 values) were determined. Out of the 8 novel compounds screened for reduced cell viability, 4c, 4d and 4e were found to be the most promising and effective ones having EC50 values that were several fold reduced when compared to the reference substance 4-hydroxycoumarin. However, the effects were cancer cell line dependent. The breast cancer MDA-MB-231 cells, the prostate cancer LNCaP cells, and U937 cells were most sensitive, MCF-7 cells were less sensitive, and PC-3 cells were more resistant. Reduced cell viability was accompanied by increased apoptosis as shown by PARP-1 cleavage and reduced activity of the survival protein kinase Akt. In summary, this study has identified three novel coumarin derivatives that in comparison to 4-hydroxycoumarin have a higher efficiency to reduce cancer cell viability and trigger apoptosis and therefore may represent interesting novel drug candidates

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pododermatitis is frequent in captive flamingos worldwide, but little is known about the associated histopathologic lesions. Involvement of a papillomavirus or herpesvirus has been suspected. Histopathologic evaluation and viral assessment of biopsies from 19 live and 10 dead captive greater flamingos were performed. Selected samples were further examined by transmission electron microscopy and immunohistochemistry. Feet from 10 dead free-ranging greater flamingos were also evaluated. The histologic appearance of lesions of flamingos of increasing age was interpreted as the progression of pododermatitis. Mild histologic lesions were seen in a 3-week-old flamingo chick with no macroscopic lesions, and these were characterized by Micrococcus-like bacteria in the stratum corneum associated with exocytosis of heterophils. The inflammation associated with these bacteria may lead to further histologic changes: irregular columnar proliferations, papillary squirting, and dyskeratosis. In more chronic lesions, hydropic degeneration of keratinocytes, epidermal hyperplasia, and dyskeratosis were seen at the epidermis, as well as proliferation of new blood vessels and increased intercellular matrix in the dermis. Papillomavirus DNA was not identified in any of the samples, while herpesvirus DNA was seen only in a few cases; therefore, these viruses were not thought to be the cause of the lesions. Poor skin health through suboptimal husbandry may weaken the epidermal barrier and predispose the skin to invasion of Micrococcus-like bacteria. Histologic lesions were identified in very young flamingos with no macroscopic lesions; this is likely to be an early stage lesion that may progress to macroscopic lesions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Beta toxin (CPB) is known to be an essential virulence factor in the development of lesions of Clostridium perfringens type C enteritis in different animal species. Its target cells and exact mechanism of toxicity have not yet been clearly defined. Here, we evaluate the suitability of a neonatal piglet jejunal loop model to investigate early lesions of C. perfringens type C enteritis. Immunohistochemically, CPB was detected at microvascular endothelial cells in intestinal villi during early and advanced stages of lesions induced by C. perfringens type C. This was first associated with capillary dilatation and subsequently with widespread hemorrhage in affected intestinal segments. CPB was, however, not demonstrated on intestinal epithelial cells. This indicates a tropism of CPB toward endothelial cells and suggests that CPB-induced endothelial damage plays an important role in the early stages of C. perfringens type C enteritis in pigs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND Co-speech gestures are part of nonverbal communication during conversations. They either support the verbal message or provide the interlocutor with additional information. Furthermore, they prompt as nonverbal cues the cooperative process of turn taking. In the present study, we investigated the influence of co-speech gestures on the perception of dyadic dialogue in aphasic patients. In particular, we analysed the impact of co-speech gestures on gaze direction (towards speaker or listener) and fixation of body parts. We hypothesized that aphasic patients, who are restricted in verbal comprehension, adapt their visual exploration strategies. METHODS Sixteen aphasic patients and 23 healthy control subjects participated in the study. Visual exploration behaviour was measured by means of a contact-free infrared eye-tracker while subjects were watching videos depicting spontaneous dialogues between two individuals. Cumulative fixation duration and mean fixation duration were calculated for the factors co-speech gesture (present and absent), gaze direction (to the speaker or to the listener), and region of interest (ROI), including hands, face, and body. RESULTS Both aphasic patients and healthy controls mainly fixated the speaker's face. We found a significant co-speech gesture × ROI interaction, indicating that the presence of a co-speech gesture encouraged subjects to look at the speaker. Further, there was a significant gaze direction × ROI × group interaction revealing that aphasic patients showed reduced cumulative fixation duration on the speaker's face compared to healthy controls. CONCLUSION Co-speech gestures guide the observer's attention towards the speaker, the source of semantic input. It is discussed whether an underlying semantic processing deficit or a deficit to integrate audio-visual information may cause aphasic patients to explore less the speaker's face.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Title: The perception of critical situations involving football fans – how conflicts escalate or de-escalate Authors: Brechbühl, A.1, Schumacher, A.1 & Seiler, R.1 1Institute of Sport Science, University of Bern, Switzerland Abstract: Introduction: Fan violence in the context of football matches is a prominent issue in today’s western societies and Switzerland presents no exception. A lot of research has been conducted on reasons for fan violence, mostly with fans of national teams. A prominent model is the Elaborated Social Identity Model (ESIM; Drury & Reicher, 2000): ESIM highlights the importance of interactions between the involved groups and their effect on the development of social identities. Another model is the aggravation mitigation model (AM model; Hylander & Guvå, 2010) which illustrates factors that can contribute towards an escalation or non-escalation of group violence, such as the “categorization” of the opponent group. Despite these models, research about the individual perceptions, and in particular, what factors distinguish between an escalation versus a non-escalation of a potentially violent situation in domestic football, is as yet scarce. This explorative study examines perceptions of critical situations in the domestic football fan context in Switzerland. Methods: An explorative qualitative design was employed to gather data about critical situations (CS) around football matches of two clubs of the Raiffeisen Super League. A CS is defined as a setting in or around the football stadium where violence between football fans and another group could occur. Eight CS were identified and analysed. Fifty-nine narrative interviews with individuals involved in a CS, e.g. fans, police officers or security personnel, were conducted. Interviews were analysed using interpretative phenomenological analysis (IPA). Results: The involved opposing groups expressed group-specific perceptions. Furthermore a strong tendency to negatively stereotype the opponent group was observed. Provocative symbols, such as balaclavas or riot-gear uniforms, were considered as highly relevant for the interpretation of the situation. Successful communication and sufficient distance between opponent groups supported the appeasement of a CS. These findings also underline the importance of knowledge about the local fan culture. This culture serves as basis for the perception of legitimacy, which was assessed to be essential for a de-escalation of a CS by fans. Discussion/Conclusion: This study improves the understanding of fan violence in the domestic football context in Switzerland. Based on the results it is suggested to deploy security or police forces without riot gear but with the goal of seeking dialogue with the fans to increase the likelihood of a peaceful ending in a CS. The findings also support the applicability of the ESIM (Drury & Reicher, 2000) and the AM model (Hylander & Guvå, 2010) in the context of domestic fan violence. Due to possible differences in the local fan cultures in Switzerland, research in this area should be continued. References: Drury, J., & Reicher, S. (2000). Collective action and psychological change: The emergence of new social identities. British Journal of Social Psychology, 39, 579-604. Hylander, I., & Guvå, G. (2010). Misunderstanding of out-group behaviour: Different interpretations of the same crowd events among police officers and demonstrators. Nordic Psychology, 62, 25-47.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

OBJECTIVES Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely available, validated sound pressure level (SPL) meter. Therefore, this study measures sound levels in movie theaters to determine whether sound levels exceed safe occupational noise exposure limits and whether sound levels in movie theaters differ as a function of movie, movie theater, presentation time, and seat location within the theater. DESIGN Six smart phones with an SPL meter software application were calibrated with a precision SPL meter and validated as an SPL meter. Additionally, three different smart phone generations were measured in comparison to an integrating SPL meter. Two different movies, an action movie and a children's movie, were measured six times each in 10 different venues (n = 117). To maximize representativeness, movies were selected focusing on large release productions with probable high attendance. Movie theaters were selected in the San Francisco, CA, area based on whether they screened both chosen movies and to represent the largest variety of theater proprietors. Measurements were analyzed in regard to differences between theaters, location within the theater, movie, as well as presentation time and day as indirect indicator of film attendance. RESULTS The smart phone measurements demonstrated high accuracy and reliability. Overall, sound levels in movie theaters do not exceed safe exposure limits by occupational standards. Sound levels vary significantly across theaters and demonstrated statistically significant higher sound levels and exposures in the action movie compared to the children's movie. Sound levels decrease with distance from the screen. However, no influence on time of day or day of the week as indirect indicator of film attendance could be found. CONCLUSIONS Calibrated smart phones with an appropriate software application as used in this study can be utilized as a validated SPL meter. Because of the wide availability, smart phones in combination with the software application can provide high quantity recreational sound exposure measurements, which can facilitate the identification of potential noise hazards. Sound levels in movie theaters decrease with distance to the screen, but do not exceed safe occupational noise exposure limits. Additionally, there are significant differences in sound levels across movie theaters and movies, but not in presentation time.