‚Wenn wir nicht losgehen, geht niemand los‘

Jessica Bocks Aufsatz mit dem Titel ‚Wenn wir nicht losgehen, geht niemand los‘: Die ostdeutsche Frauenbewegung von 1980 bis 2000 am Beispiel der Stadt Leipzig füllt eine Lücke in der jüngsten Zeitgeschichte, indem er Frauen als handelnde historische Subjekte der Oppositions- und Revolutionsgeschichte sichtbar macht. Am Beispiel von Petra Lux werden wesentliche Entwicklungslinien und Eigenheiten der Leipziger Frauenbewegung 1980- 2000 dargestellt. Hierbei wird deutlich, dass Frauen in jeder Phase, sei es in der SED-Diktatur, in Zeiten des Umbruchs oder in einer Demokratie um ihre Anerkennung als politische Subjekte mit ihren Bedürfnissen und Forderungen sowie um die Erweiterung ihrer Entscheidungs- und Handlungsmöglichkeiten kämpfen mussten. Gleichzeitig muss die ostdeutsche Frauenbewegung trotz systembedingter Eigenheiten auch im Kontakt mit Westdeutschland als Teil einer gesamtdeutschen feministischen Entwicklung gesehen werden, wobei der Aufsatz durch seinen geografischen Fokus auf der Stadt Leipzig unterstreicht, dass Frauen auch außerhalb von (Ost-)Berlin aktiv waren

Open-Cell Metal Foams for Use in Dehumidifying Heat Exchangers

Metal foams with an open-cell structure have physical and mechanical properties suggesting they might have advantages over conventional fin materials for use in air-cooling heat exchangers. For example, metal foams are low weight, have high to very high specific surface area (up to over 10000 m2/m3), have high gas permeability, and have relatively high thermal conductivity (for open-cell bodies). Due to these properties, open-cell metal foams have been studied for many heat transfer applications, especially as a material for constructing efficient compact heat exchangers. In this work, dynamic dips tests are undertaken to explore the water-drainage behavior of the metal foams. Experiments are also undertaken in a closed-loop wind tunnel to evaluate the pressure drop and heat transfer performance of metal foam heat exchangers under dry- and wet-surface conditions

Vapor-liquid equilibria of a low GWP refrigerant, R-1234ze(E), mixed with a POE lubricant

Novel vapor-liquid-equilibria data (P-T-x) and liquid densities of binary mixtures of an emerging low-GWP (Global Warming Potential) refrigerant, R-1234ze(E), and a polyol ester (POE) oil, RL68H, are measured. Data are presented for oil mass fractions ranging from 0 to 0.85 over a temperature range from -10 to 60°C, and the results are compared to the properties of mixtures of R-134a with RL68H. In addition to providing new pure-refrigerant and refrigerant/oil property data, a comparison of the performance of five mixture models is undertaken, namely: the Wilson model, NRTL, UNIQUAC, Heil, and Raoult’s law. Overall, the Heil model provides the best agreement in pressure predictions for R-1234ze(E)/RL68H mixtures, with RMS deviations less than 0.5%, while NRTL RMS deviations are less than 1%. However, comparable performance was found for the much simpler Raoult’s law, with increased deviations at the highest oil concentration. Model sensitivity and applicability of Raoult’s law for refrigerant/oil mixtures in general are investigated. The experimental data and modeling results presented are especially valuable for engineers working in the automotive air-conditioning and refrigeration industries. The refrigerant R-1234ze(E) is one of the leading alternatives for replacing R-134a and is a member of the HFO family of chemicals that includes other low-GWP refrigerants. Accurate models for the new refrigerants and refrigerant/oil mixtures are essential for designing and analyzing refrigeration and air-conditioning systems with reduced environmental impact

A New Design Paradigm for Secure Full-Duplex Multiuser Systems

We consider a full-duplex (FD) multiuser system where an FD base station (BS) is designed to simultaneously serve both downlink (DL) and uplink (UL) users in the presence of half-duplex eavesdroppers (Eves). The problem is to maximize the minimum (max-min) secrecy rate (SR) among all legitimate users, where the information signals at the FD-BS are accompanied with artificial noise to debilitate the Eves' channels. To enhance the max-min SR, a major part of the power budget should be allocated to serve the users with poor channel qualities, such as those far from the FD-BS, undermining the SR for other users, and thus compromising the SR per-user. In addition, the main obstacle in designing an FD system is due to the self-interference (SI) and co-channel interference (CCI) among users. We therefore propose an alternative solution, where the FD-BS uses a fraction of the time block to serve near DL users and far UL users, and the remaining fractional time to serve other users. The proposed scheme mitigates the harmful effects of SI, CCI and multiuser interference, and provides system robustness. The SR optimization problem has a highly nonconcave and nonsmooth objective, subject to nonconvex constraints. For the case of perfect channel state information (CSI), we develop a low-complexity path-following algorithm, which involves only a simple convex program of moderate dimension at each iteration. We show that our path-following algorithm guarantees convergence at least to a local optimum. Then, we extend the path-following algorithm to the cases of partially known Eves' CSI, where only statistics of CSI for the Eves are known, and worst-case scenario in which Eves can employ a more advanced linear decoder. The merit of our proposed approach is further demonstrated by extensive numerical results.Comment: Accepted for publication in IEEE Journal on Selected Areas in Communications (JSAC), 201

Welche Rolle spielen Kinder in Schulen und Kindertagesstätten bei der Übertragung von SARS-CoV-2? – Eine evidenzbasierte Perspektive

Are children and adolescents relevant disease vectors when it comes to the transmission of SARS-CoV-2? Moreover, do they play a role as relevant disease vectors in a~school or kindergarten setting? These questions could not be sufficiently answered at the beginning of the pandemic. Consequently, schools and childcare facilities were closed to stop the spread of SARS-CoV\hbox-2. Over the past few months, researchers have gained a~more detailed understanding of the overall pandemic situation. The SARS-CoV\hbox-2 infection rate in children below 10~years of age in 2020 has been substantially lower than in adults. In addition, it showed that children had a~milder course of disease.Although a~majority of the analyses performed in schools and childcare facilities revealed that the virus is transmitted in these facilities, these transmissions did not, however, have a~considerable influence on the overall rate of new infections. Despite these findings, German politicians continue to advocate for the closure of childcare facilities, including schools, to fight the pandemic, whereas many specialist societies such as the German Society for Pediatric Infectious Diseases (DGPI) have emphasized that such closures should be the measure of last resort in combating the pandemic. The same message is also conveyed by a~German evidence-based S3~guideline established by an interdisciplinary expert group that had already put forward clear recommendations for high incidences in the general population at the beginning of February 2021, indicating that school closures were only required in exceptional cases.In this article, we would like to outline the situation based on the currently available data, try to predict the future, and discuss the circumstances necessary to realize normal classroom teaching without accepting the risk of an uncontrolled spread of SARS-CoV\hbox-2. ZUSAMMENFASSUNG Sind Kinder und Jugendliche relevante Vektoren für die Übertragung von SARS-CoV-2? Und welche Rolle spielt es, wenn sie eine Schule oder Kindertagesstätte besuchen? Diese Fragen konnten zu Beginn der Pandemie nur unzureichend beantwortet werden. So wurden weltweit Schulen und Kinderbetreuungseinrichtungen geschlossen, um die Verbreitung von SARS-CoV\hbox-2 einzudämmen. Inzwischen ist die Rolle von Kindern im Gesamtgeschehen der Pandemie jedoch klarer. Die Rate von SARS-CoV-2-Infektionen bei Kindern unter 10~Jahren war im Jahr 2020 deutlich niedriger als die bei Erwachsenen. Zudem zeigte sich bei Kindern ein deutlich milderer Verlauf der Erkrankung.Analysen zu Ausbrüchen an Schulen und Kinderbetreuungseinrichtungen kamen mehrheitlich zu dem Ergebnis, dass die Weitergabe des Virus in den Einrichtungen zwar stattfindet, jedoch das Infektionsgeschehen insgesamt nicht maßgeblich beeinflusst. Trotz dieser Erkenntnisse hält die deutsche Politik Schulschließungen weiterhin für einen integralen Baustein der Pandemiebekämpfung, wohingegen viele Fachgesellschaften, wie die Deutsche Gesellschaft für Pädiatrische Infektiologie e. V. (DGPI), betonen, dass es sich um das letzte Mittel in der Bekämpfung der Pandemie handeln sollte. Diese Botschaft hat auch eine evidenzbasierte und auf interdisziplinärem Expertenkonsens aufgebaute S3-Leitlinie, die bereits Anfang Februar 2021 klare Empfehlungen für Zeiten hoher Inzidenzen in der Gesamtbevölkerung ausgesprochen hat, die Schulschließungen nur noch in Ausnahmefällen für notwendig erachten.In diesem Artikel möchten wir die Datenlage mit Stand Juni 2021 zu diesem Thema darlegen, einen Blick in die Zukunft wagen und diskutieren, unter welchen Umständen ein regulärer Präsenzunterricht gelingen kann, ohne das Risiko einer unkontrollierten Ausbreitung von SARS-CoV\hbox-2 in Kauf nehmen zu müssen

Application of alternative cell separation systems for the harvest of mammalian cell culture processes in a fully disposable single-use facility

In a fully disposable facility where the use of continuous disk-stack centrifuges are not preferred, harvest processes based on conventional depth filtration become more challenging with increasing single-use bioreactor (SUB) size and higher density culture. Lower filterability due to high volume and high cell density diminishes the efficiency of the depth filtration. In addition, the use of larger depth filtration systems is constrained by the facility footprint. To address the challenge described, several alternative single-use harvest technologies were evaluated. A disposable centrifuge with a small foot print, low consumable cost, and ease of operation was tested. In a study using a 1kL SUB for harvest, the disposable centrifuge was compared to a continuous disk-stack centrifuge, both followed by conventional depth filtration. The best operating conditions, as well as the edges of failures, were found for the disposable centrifuge. When compared to the disk-stack centrifuge results showed that the operation can be performed in a wide range without impacting depth filtration area requirements and less depth filter area was needed. In addition to testing a disposable centrifuge, flocculation was evaluated and compared, followed by the depth filtration. This was found to be another low-cost alternative process, while also occupying less facility space. The flocculation technology was tested with different cell lines and results showed significant improvement in filterability and reduction of depth filter area compared to full traditional depth filtration train

Dynamics of a Staphylococcus aureus infective endocarditis simulation model

Infective endocarditis (IE) is a serious infection of the inner surface of heart, resulting from minor lesions in the endocardium. The damage induces a healing reaction, which leads to recruitment of fibrin and immune cells. This sterile healing vegetation can be colonized during temporary bacteremia, inducing IE. We have previously established a novel in vitro IE model using a simulated IE vegetation (IEV) model produced from whole venous blood, on which we achieved stable bacterial colonization after 24h. The bacteria were organized in biofilm aggregates and displayed increased tolerance towards antibiotics. In this current study, we aimed at further characterizing the time course of biofilm formation and the impact on antibiotic tolerance development. We found that a S. aureus reference strain, as well as three clinical IE isolates formed biofilms on the IEV after 6h. When treatment was initiated immediately after infection, the antibiotic effect was significantly higher than when treatment was started after the biofilm was allowed to mature. We could follow the biofilm development microscopically by visualizing growing bacterial aggregates on the IEV. The findings indicate that mature, antibiotic-tolerant biofilms can be formed in our model already after 6h, accelerating the screening for optimal treatment strategies for IE

Recent Patterns in Population-Based HIV Prevalence in Swaziland

Background: The 2011 Swaziland HIV Incidence Measurement Survey (SHIMS) was conducted as part of a national study to evaluate the scale up of key HIV prevention programs. Methods: From a randomly selected sample of all Swazi households, all women and men aged 18-49 were considered eligible, and all consenting adults were enrolled and received HIV testing and counseling. In this analysis, population-based measures of HIV prevalence were produced and compared against similarly measured HIV prevalence estimates from the 2006-7 Swaziland Demographic and Health. Also, measures of HIV service utilization in both HIV infected and uninfected populations were documented and discussed. Results: HIV prevalence among adults aged 18-49 has remained unchanged between 2006-2011 at 31-32%, with substantial differences in current prevalence between women (39%) and men (24%). In both men and women, between since 2006-7 and 2011, prevalence has fallen in the young age groups and risen in the older age groups. Over a third (38%) of the HIV-infected population was unaware of their infection status, and this differed markedly between men (50%) and women (31%). Of those aware of their HIV-positive status, a higher percentage of men (63%) than women (49%) reported ART use. Conclusions: While overall HIV prevalence remains roughly constant, age-specific changes strongly suggest both improved survival of the HIV-infected and a reduction in new HIV infections. Awareness of HIV status and entry into ART services has improved in recent years but remains too low. This study identifies opportunities to improve both HIV preventive and care services in Swaziland

A primate model of severe malarial anaemia: a comparative pathogenesis study.

Severe malarial anaemia (SMA) is the most common life-threatening complication of Plasmodium falciparum infection in African children. SMA is characterised by haemolysis and inadequate erythropoiesis, and is associated with dysregulated inflammatory responses and reduced complement regulatory protein levels (including CD35). However, a deeper mechanistic understanding of the pathogenesis requires improved animal models. In this comparative study of two closely related macaque species, we interrogated potential causal factors for their differential and temporal relationships to onset of SMA. We found that rhesus macaques inoculated with blood-stage Plasmodium coatneyi developed SMA within 2 weeks, with no other severe outcomes, whereas infected cynomolgus macaques experienced only mild/ moderate anaemia. The abrupt drop in haematocrit in rhesus was accompanied by consumption of haptoglobin (haemolysis) and poor reticulocyte production. Rhesus developed a greater inflammatory response than cynomolgus macaques, and had lower baseline levels of CD35 on red blood cells (RBCs) leading to a significant reduction in the proportion of CD35+ RBCs during infection. Overall, severe anaemia in rhesus macaques infected with P. coatneyi has similar features to SMA in children. Our comparisons are consistent with an association of low baseline CD35 levels on RBCs and of early inflammatory responses with the pathogenesis of SMA