Overview of the MOSAiC expedition - Atmosphere

With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore cross-cutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge. The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled-system scientific research and provide an important foundation for advancing multiscale modeling capabilities in the Arctic

Effects of VO2-uptake adjusted downhill and uphill running on cfDNA and conventional exercise markers

Introduction We observed in previous studies that running leads to significantly higher increases of cell-free DNA (cfDNA) in capillary blood than a comparable cycling protocol. Following the idea that this effect might be based on the more eccentric nature of running compared to cy-cling, we examined here whether uphill or downhill running adjusted to VO2-uptake leads to a differential effect on physiological markers and cfDNA increases. Methods Following VO2max-testing ten male triathletes took part in four different endurance runs (group). A 5 min warm-up, was followed by 3x10 min at either 60 % or 80 % of VO2-max at -3.5 % or +6.5 % incline on a treadmill. The tests included continuous recording of spi-roergometric data, and assessment of heart rate, lactate and cfDNA at rest, following warm-up, after every 10min interval, and 3, 15, and 30min after the runs. The normalized and homoscedastic Data fulfilling sphericity conditions were analyzed by multifactorial analysis of variance with up/down, 60%/80% and point in time (Rest, 10’, 20’, 30’) as influ-ential factors. Results Compared with lactate, heart rate, and RER, cfDNA showed the most robust and signifi-cant step-wise increases during the run with an 8.0-fold (95% CI: 6.4-9.9; p < 0.0001) in-crease from rest to 30 min, adjusted for intensity and up/down. Except for heart rate none of the other factors was able to differentiate between uphill and downhill running at 60% of VO2max. However at 80% VO2 max heart rate was not able to differentiate between up-hill/downhill, while cfDNA values were on average 2.0-fold (95% CI: 1.6-2.5; p < 0.0001) higher during downhill running at a significance level equal to the RER (p < 0.0001) and much higher than lactate (p = 0.03), both showing slightly higher values downhill. Discussion Compared to other physiological markers cfDNA reacts more sensitive to different intensi-ties over a course of an endurance run. Compared to lactate, it showed a stronger asso-ciation with eccentric load and duration of exposure. This suggests that the cfDNA could be a more sensitive marker especially in intermittent sports with varying intensity and du-ration and in particular varying eccentric load proportions than conventional exercise markers

Unterschiedliche Akuteffekte von bergauf und bergab Dauerläufen auf die cfDNA und gängigen Belastungsmarkern

Einleitung In vorhergehenden Untersuchungen konnte beobachtet werden, dass Laufbelastungen zu deutlich höheren freizirkulierenden DNA (cfDNA) Werten führen, als Fahrradbelastungen. Hier wurde untersucht, wie sich unter kontrollierten Laborbedingungen Dauerläufe, die bergab (exzentrischer) oder bergauf (konzentrischer) bei gleicher auf die VO2-max adjus-tierten Belastungsintensität durchgeführt werden, auf Belastungsmarker und die cfDNA auswirken. Methode Nach Erhebung der VO2-max durch eine stufenweise Ausbelastung (Start: 6 km/h; Pause: 30 sec; Steigerung: 2 km/h; Steigung: +1,5 %) absolvierten zehn gesunde männliche Tri-athleten an vier Untersuchungstagen nach definiertem Aufwärmen je 3x10 min bei 60 % oder 80 % der VO2-max bei 3,5 % Gefälle oder 6,5 % Steigung Dauerbelastungen auf dem Laufbandergometer. Spiroergometrische Messgrößen wurden kontinuierlich sowie Herzfrequenz, Laktat, cfDNA vor Beginn, nach der Warm-up Phase, nach 10, 20 und 30 min und in der Erholung (3, 15 und 30 min) und rate of perceived exertion (RPE) zwischen den 10 min Blöcken erhoben. Die normalisierten und homoskedastischen Daten wurden mittels einer multifaktoriellen Varianz Analyse unter Berücksichtigung der Einflussfaktoren uphill/downhill, 60%/80% VO2-max und die Messzeitpunkte (vor Beginn, 10, 20 und 30 min) analysiert. Ergebnisse Im Vergleich zu Laktat, Herzfrequenz und RER zeigte die cfDNA robustere und signifikant höhere Anstiege während der Dauerbelastung mit einem 8-fachen (95% KI: 6.4-9.9; p< 0.0001) Anstieg vom Messzeitpunkt vor Beginn zu 30 min auf, welcher auf die Intensität und uphill/downhill adjustiert ist. Außer die Herzfrequenz konnten die anderen physiologi-schen Parameter keinen Unterschied zwischen uphill und downhill bei 60% der VO2-max darstellen. Bei 80% der VO2-max konnte die Herzfrequenz keinen Unterschied zwischen uphill und downhill aufweisen. cfDNA konnte im Mittel einen 2-fach (95% KI: 1.6-2.5; p< 0.0001) erhöhten Anstieg bei downhill 80% der VO2-max gegenüber uphill 80% der VO2-max aufweisen. Ähnliche hohe signifikante Unterschied weist der RER (p < 0.0001) auf und nur einen niedrigen signifikanten Unterschied das Laktat (p = 0.03). Diskussion Im Vergleich zu anderen Belastungsmarkern reagiert die cfDNA nicht nur hoch sensitiv auf Intensitätsunterschiede, sondern sie weist insbesondere gegenüber dem Laktat eine stär-kere Assoziation mit exzentrischer Belastung und mit der Dauer einer Belastung auf. Dies legt nahe, dass die cfDNA insbesondere in intermittierenden Sportarten mit variierender Intensität und Dauer sowie insbesondere variierenden exzentrischen Belastungsanteilen ein sensitiverer Belastungsmarker sein könnte als konventionelle Marker

Physical exercise induces rapid release of small extracellular vesicles into the circulation

Cells secrete extracellular vesicles (EVs) by default and in response to diverse stimuli for the purpose of cell communication and tissue homeostasis. EVs are present in all body fluids including peripheral blood, and their appearance correlates with specific physiological and pathological conditions. Here, we show that physical activity is associated with the release of nano-sized EVs into the circulation. Healthy individuals were subjected to an incremental exercise protocol of cycling or running until exhaustion, and EVs were isolated from blood plasma samples taken before, immediately after and 90 min after exercise. Small EVs with the size of 100–130 nm, that carried proteins characteristic of exosomes, were significantly increased immediately after cycling exercise and declined again within 90 min at rest. In response to treadmill running, elevation of small EVs was moderate but appeared more sustained. To delineate EV release kinetics, plasma samples were additionally taken at the end of each increment of the cycling exercise protocol. Release of small EVs into the circulation was initiated in an early phase of exercise, before the individual anaerobic threshold, which is marked by the rise of lactate. Taken together, our study revealed that exercise triggers a rapid release of EVs with the characteristic size of exosomes into the circulation, initiated in the aerobic phase of exercise. We hypothesize that EVs released during physical activity may participate in cell communication during exercise-mediated adaptation processes that involve signalling across tissues and organs

Physical exercise induces rapid release of small extracellular vesicles into the circulation

Cells secrete extracellular vesicles (EVs) by default and in response to diverse stimuli for the purpose of cell communication and tissue homeostasis. EVs are present in all body fluids including peripheral blood, and their appearance correlates with specific physiological and pathological conditions. Here, we show that physical activity is associated with the release of nano-sized EVs into the circulation. Healthy individuals were subjected to an incremental exercise protocol of cycling or running until exhaustion, and EVs were isolated from blood plasma samples taken before, immediately after and 90 min after exercise. Small EVs with the size of 100-130 nm, that carried proteins characteristic of exosomes, were significantly increased immediately after cycling exercise and declined again within 90 min at rest. In response to treadmill running, elevation of small EVs was moderate but appeared more sustained. To delineate EV release kinetics, plasma samples were additionally taken at the end of each increment of the cycling exercise protocol. Release of small EVs into the circulation was initiated in an early phase of exercise, before the individual anaerobic threshold, which is marked by the rise of lactate. Taken together, our study revealed that exercise triggers a rapid release of EVs with the characteristic size of exosomes into the circulation, initiated in the aerobic phase of exercise. We hypothesize that EVs released during physical activity may participate in cell communication during exercise-mediated adaptation processes that involve signalling across tissues and organs

Experimental and numerical studies of saturation overshoot during infiltration into a dry soil

\u3cp\u3eDownward infiltration of water into almost dry soil, when there is no ponding at the soil surface, often occurs in the form of fingers, with saturation overshoot at the finger tips. While this is well known, there is still uncertainty about the exact saturation pattern within fingers. We performed a series of one-dimensional water infiltration experiments into a dry soil to study the non-monotonicity of the saturation. We observed that saturation showed a non-monotonic behavior as a function of time. The overshoot was somewhat plateau shaped at relatively low flow rates but was quite sharp at higher flow rates. Two mathematical models, referred to as the extended standard (ESD) model and the interfacial area (IFA) model, were used to simulate the experimental results. Both models were based on extended forms of the Richards equation by including a dynamic capillary term. In the ESD model, standard equations for hysteresis were used. In the IFA model, the specific interfacial area was introduced to simulate hysteresis. Parameter values for both models were obtained from preliminary experiments or using empirical formulas. Only one parameter, the dynamic capillarity coefficient t, was optimized to model saturation overshoot. While the ESD model did not reproduce the form of saturation overshoot for any combination of parameter values, the IFA model could provide good agreement with the data. To our knowledge, this is the first time where a combination of the IFA model and the dynamic capillarity equation has been used to simulate a set of experiments.\u3c/p\u3

Experimental and numerical studies of saturation overshoot during infiltration into a dry soil

Downward infiltration of water into almost dry soil, when there is no ponding at the soil surface, often occurs in the form of fingers, with saturation overshoot at the finger tips. While this is well known, there is still uncertainty about the exact saturation pattern within fingers. We performed a series of one-dimensional water infiltration experiments into a dry soil to study the non-monotonicity of the saturation. We observed that saturation showed a non-monotonic behavior as a function of time. The overshoot was somewhat plateau shaped at relatively low flow rates but was quite sharp at higher flow rates. Two mathematical models, referred to as the extended standard (ESD) model and the interfacial area (IFA) model, were used to simulate the experimental results. Both models were based on extended forms of the Richards equation by including a dynamic capillary term. In the ESD model, standard equations for hysteresis were used. In the IFA model, the specific interfacial area was introduced to simulate hysteresis. Parameter values for both models were obtained from preliminary experiments or using empirical formulas. Only one parameter, the dynamic capillarity coefficient t, was optimized to model saturation overshoot. While the ESD model did not reproduce the form of saturation overshoot for any combination of parameter values, the IFA model could provide good agreement with the data. To our knowledge, this is the first time where a combination of the IFA model and the dynamic capillarity equation has been used to simulate a set of experiments

Experimental and numerical studies of saturation overshoot during infiltration into a dry soil

Downward infiltration of water into almost dry soil, when there is no ponding at the soil surface, often occurs in the form of fingers, with saturation overshoot at the finger tips. While this is well known, there is still uncertainty about the exact saturation pattern within fingers. We performed a series of one-dimensional water infiltration experiments into a dry soil to study the non-monotonicity of the saturation. We observed that saturation showed a non-monotonic behavior as a function of time. The overshoot was somewhat plateau shaped at relatively low flow rates but was quite sharp at higher flow rates. Two mathematical models, referred to as the extended standard (ESD) model and the interfacial area (IFA) model, were used to simulate the experimental results. Both models were based on extended forms of the Richards equation by including a dynamic capillary term. In the ESD model, standard equations for hysteresis were used. In the IFA model, the specific interfacial area was introduced to simulate hysteresis. Parameter values for both models were obtained from preliminary experiments or using empirical formulas. Only one parameter, the dynamic capillarity coefficient t, was optimized to model saturation overshoot. While the ESD model did not reproduce the form of saturation overshoot for any combination of parameter values, the IFA model could provide good agreement with the data. To our knowledge, this is the first time where a combination of the IFA model and the dynamic capillarity equation has been used to simulate a set of experiments

Influence of nanoparticle-mediated transfection on proliferation of primary immune cells in vitro and in vivo

Introduction: One of the main obstacles in the widespread application of gene therapeutic approaches is the necessity for efficient and safe transfection methods. For the introduction of small oligonucleotide gene therapeutics into a target cell, nanoparticle-based methods have been shown to be highly effective and safe. While immune cells are a most interesting target for gene therapy, transfection might influence basic immune functions such as cytokine expression and proliferation, and thus positively or negatively affect therapeutic intervention. Therefore, we investigated the effects of nanoparticle-mediated transfection such as polyethylenimine (PEI) or magnetic beads on immune cell proliferation. Methods: Human adherent and non-adherent PBMCs were transfected by various methods (e.g. PEI, Lipofectamine® 2000, magnetofection) and stimulated. Proliferation was measured by lymphocyte transformation test (LTT). Cell cycle stages as well as expression of proliferation relevant genes were analyzed. Additionally, the impact of nanoparticles was investigated in vivo in a murine model of the severe systemic immune disease GvHD (graft versus host disease). Results: The proliferation of primary immune cells was influenced by nanoparticle-mediated transfection. In particular in the case of magnetic beads, proliferation inhibition coincided with short-term cell cycle arrest and reduced expression of genes relevant for immune cell proliferation. Notably, proliferation inhibition translated into beneficial effects in a murine GvHD model with animals treated with PEI-nanoparticles showing increased survival (pPEI = 0.002) most likely due to reduced inflammation. Conclusion: This study shows for the first time that nanoparticles utilized for gene therapeutic transfection are able to alter proliferation of immune cells and that this effect depends on the type of nanoparticle. For magnetic beads, this was accompanied by temporary cell cycle arrest. Notably, in GvHD this nonspecific anti-proliferative effect might contribute to reduced inflammation and increased survival