Wie lernt es sich gemeinsam im virtuellen Raum? Didaktische und soziale Dimensionen von Breakout-Rooms

Der Beitrag untersucht die didaktischen und sozialen Dimensionen des kooperativen Lernens in Breakout-Rooms. Letztere werden als soziale Arrangements definiert, deren Interaktionsprozesse unter bestimmten Bedingungen lernforderliche Wirkung erzielen können. Im Rahmen eines Mixed-Methods-Ansatzes werden Studierende eines berufspädagogischen Masterstudiengangs befragt, wobei in einer quantitativen Erhebung zunächst ihre Einschätzungen in Bezug auf Rahmenbedingungen und Merkmale von Breakout-Rooms untersucht werden. In der anschließenden qualitativen Erhebung werden diese Befunde vertieft und die Studierenden danach gefragt, was die Qualität der Zusammenarbeit ausmacht. Die Ergebnisse unterstreichen den Einfluss, den Faktoren wie Zeit, Gruppengröße und Gruppenzusammensetzung auf die Zusammenarbeit in Breakout-Rooms haben. Folglich verlangen virtuelle Räume einen reflektierten Einsatz von Methoden und klar strukturierte Arbeitsaufträge. Die Lehrperson tritt dabei nur scheinbar in den Hintergrund, denn ihre Rolle bleibt für die Vorbereitung und Moderation des Lernprozesses ebenso entscheidend wie für dessen Ergebnissicherung. Einige dieser Implikationen bringen wir abschließend in Vorschlägen für den Praxistransfer auf den Punkt. (DIPF/Orig.

Application of agronomic practice improves phytoextraction on a multipolluted site

In the context of a joint research project in collaboration with the municipal water works of Leipzig, BioPlanta optimizes the phytoremediation process. This Phytotechnology has been applied since 1996 to a former sewage sludge dewatering plant in Schladitz near Leipzig (Fig 1). At the time of closing in 1990 about 300,000 m3 of heavy metal‐ and hydrocarbon‐contaminated sludge were stored on this site. It is the biggest phytoremediation project of this kind in Europe. An extensive monitoring and analysis program was established to evaluate the progress of the remediation (ending in 2012). Up to now the contamination of the site could be considerably decreased. The removal of heavy metals sums up to several kilograms with an increasing tendency over the last years (Fig 2). The aim of ongoing research activities is to set up improved conditions for an even more efficient extraction of heavy metal ions from contaminated soil and sediments. Optimizing this process should reduce the remediation period by up to two thirds. The technology is to be implemented not only in the Leipzig region but also in future remediation projects. Agronominių priemonių taikymas, gerinant fitoekstrakciją įvairiais teršalais užterštose vietose Santrauka Vykdydama bendrą tiriamąjį projektą atliekant vandens tyrimus Leipcige BioPlanta optimizuoja fitoatkūrimo procesą. Ši fitotechnologija taikoma nuo 1996 metų ankstesnei iš nuotekų dumblo vandenį šalinančiai įrangai Šladice netoli Leipcigo (1 pav.). Uždarant įrangą 1990 metais apie 300 000 m3 dumblo, užteršto sunkiaisiais metalais ir angliavandeniliais, buvo sukaupta šiame sklype. Tai didžiausias tokio pobūdžio fitoatkūrimo projektas Europoje. Buvo sukurta plati monitoringo ir analizės programa siekiant įvertinti atkūrimo eigą (iki 2012 metų). Sklypo tarša galėjo labai sumažėti. Sunkiųjų metalų pašalinimas siekia daugiau kaip kelis kilogramus su didėjimo tendencija pastaraisiais metais (2 pav.). Tyrimo tikslas – sudaryti geresnes sąlygas dar efektyvesnei sunkiųjų metalų jonų ekstrakcijai iš užteršto dirvožemio ir nuosėdų. Optimizuojant šį procesą atkūrimo laikotarpis turėtų sutrumpėti iki dviejų trečdalių. Ši technologija turi būti įgyvendinama ateityje vykdant atkūrimo projektus. Reikšminiai žodžiai: fitoatkūrimas, metalų biogalimybės, augalų parinkimas, pasėlių priežiūra, augalų biomasė. Применение агрономических средств для улучшения фитоэкстракции в местах, загрязненных несколькими загрязнителями Резюме В результате сотрудничества с самоуправлением Лейпцига в создании общего проекта исследований по вопросам водных работ «БиоПланта» оптимизирует процесс фиторемедиации. Эта фитотехнология применялась в Шладице около Лейпцига с 1996 г. в оборудовании по удалению воды из ила сточных вод (Рис. 1). После 1990 г., когда упомянутое оборудование перестало применяться, на участке было собрано 300 000 м3 ила, загрязненного тяжелыми металлами и углеводородом. Это самый крупный проект фиторемедиации такого типа в Европе. Для оценки эффективности процесса восстановления до 2012 г. будет создана широкая программа мониторинга и анализа. Загрязнение этого места должно значительно уменьшиться. Загрязнение тяжелыми металлами составляет несколько килограммов, а в последние годы имеет тенденцию к увеличению (Рис. 2). Целью проводящихся исследований было создание лучших условий для более эффективной экстракции ионов тяжелых металлов из загрязненной почвы и осадков. В результате оптимизации этого процесса период восстановления должен уменьшиться. Названная технология должна быть внедрена в Лейпцигском регионе, а также внедряться в будущем при осуществлении восстановительных проектов. Ключевые слова: фиторемедиация, биовозможности металлов, подбор растений, уход за посевами, биомасса растений. First Published Online: 14 Oct 201

Elasticity and adhesion of resting and lipopolysaccharide-stimulated macrophages

AbstractColloidal Force Microscopy was employed to study the viscoelastic and adhesive properties of macrophages upon stimulation with lipopolysaccharide (LPS). Force vs. distance measurements were performed. The adhesion of LPS-stimulated cells (separation force=37±3nN) was almost twice as high as that of resting macrophages (16±1nN). Upon retraction pulling of membrane tethers was observed. Tether lengths and forces at which rupture take place did not depend on stimulation. The reduced Young’s modulus K, a measure of cytoskeleton elasticity, was three times lower than that of the control. The data show that LPS has profound effects on cytomechanical and adhesion properties of macrophages

Web 2.0 in der akademischen Praxis: Herausforderungen und strategische Optionen

Das Web 2.0 hat die Kommunikation verändert. Dies gilt zum einen für die Kommunikation im Alltag, für die inzwischen knapp ein Drittel aller Internetnutzer in Deutschland regelmäßig auf Web 2.0-Angebote zurück greifen (Busemann & Gscheidle, 2010). Dies gilt aber auch für die Kommunikation im Hochschulkontext, wo das Web 2.0 von Seiten der Studierenden wie der Hochschulen in den Bereichen Lehre, Forschung und Verwaltung und Dienstleistungen genutzt wird (Hochschulrektorenkonferenz, 2010)

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Direct comparison of MRI and X-ray CT technologies for 3D imaging of root systems in soil: potential and challenges for root trait quantification

BackgroundRoots are vital to plants for soil exploration and uptake of water and nutrients. Root performance is critical for growth and yield of plants, in particular when resources are limited. Since roots develop in strong interaction with the soil matrix, tools are required that can visualize and quantify root growth in opaque soil at best in 3D. Two modalities that are suited for such investigations are X-ray Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). Due to the different physical principles they are based on, these modalities have their specific potentials and challenges for root phenotyping. We compared the two methods by imaging the same root systems grown in 3 different pot sizes with inner diameters of 34 mm, 56 mm or 81 mm.ResultsBoth methods successfully visualized roots of two weeks old bean plants in all three pot sizes. Similar root images and almost the same root length were obtained for roots grown in the small pot, while more root details showed up in the CT images compared to MRI. For the medium sized pot, MRI showed more roots and higher root lengths whereas at some spots thin roots were only found by CT and the high water content apparently affected CT more than MRI. For the large pot, MRI detected much more roots including some laterals than CT.ConclusionsBoth techniques performed equally well for pots with small diameters which are best suited to monitor root development of seedlings. To investigate specific root details or finely graduated root diameters of thin roots, CT was advantageous as it provided the higher spatial resolution. For larger pot diameters, MRI delivered higher fractions of the root systems than CT, most likely because of the strong root-to-soil contrast achievable by MRI. Since complementary information can be gathered with CT and MRI, a combination of the two modalities could open a whole range of additional possibilities like analysis of root system traits in different soil structures or under varying soil moisture

Regulation of Adenosine Receptor Subtypes during Cultivation of Human Monocytes: Role of Receptors in Preventing Lipopolysaccharide-Triggered Respiratory Burst

Adenosine is a potent anti-inflammatory agent that modulates the function of cells involved in the inflammatory response. Here we show that it inhibits lipopolysaccharide (LPS)-induced formation of reactive oxygen intermediates (ROI) in both freshly isolated and cultured human monocytes. Blocking of adenosine uptake and inactivation of the adenosine-degrading enzyme adenosine deaminase enhanced the inhibitory action of adenosine, indicating that both pathways regulate the extracellular adenosine concentration. Adenosine-mediated inhibition could be reversed by XAC (xanthine amine congener), an antagonist of the adenosine receptor A(2A), and MRS 1220 {N-9-chloro-2-(2-furanyl)[1, 2, 4]-triazolo[1,5-c]quinazolin-5-benzeneacetamide}, an A(3) receptor antagonist, in both cell populations, while DPCPX (1,3-dipropyl-8-cyclopentylxanthine), an A(1) receptor antagonist, had no effect. Similar to what was seen with adenosine, CGS 21680, an A(2A) and A(3) receptor agonist, and IB-MECA, a nonselective A(1) and A(3) receptor agonist, dose dependently prevented ROI formation, indicating the involvement of A(3) and probably also A(2A) in the suppressive effect of adenosine. Pretreatment of monocytes with adenosine did not lead to changes in the LPS-induced increase in intracellular calcium levels ([Ca(2+)](i)). Thus, participation of [Ca(2+)](i) in the action of adenosine seems unlikely. The adenosine-mediated suppression of ROI production was found to be more pronounced when monocytes were cultured for 18 h, a time point at which changes in the mRNA expression of adenosine receptors were observed. Most prominent was the increase in the A(2A) receptor mRNA. These data demonstrate that cultivation of monocytes is accompanied by changes in the inhibitory action of adenosine mediated by A(3) and probably also the A(2A) receptor and that regulation of adenosine receptors is an integral part of the monocyte differentiation program