A long-term passive sampling approach for wastewater-based monitoring of SARS-CoV-2 in Leipzig, Germany

Wastewater-based monitoring of SARS-CoV-2 has become a promising and useful tool in tracking the potential spread or dynamics of the virus. Its recording can be used to predict how the potential number of infections in a population will develop. Recent studies have shown that the use of passive samplers is also suitable for the detection of SARS-CoV-2 genome copies (GC) in wastewater. They can be used at any site, provide timely data and may collect SARS-CoV-2 GC missed by traditional sampling methods. Therefore, the aim of this study was to evaluate the suitability of passive samplers for the detection of SARS-CoV-2 GC in wastewater in the long-term at two different scales. Polyethylene-based plastic passive samplers were deployed at the city-scale level of Leipzig at 13 different locations, with samples being taken from March 2021 to August 2022. At the smaller city district level, three types of passive samplers (cotton-cloth, unravelled polypropylene plastic rope and polyethylene-based plastic strips) were used and sampled on a weekly basis from March to August 2022. The results are discussed in relation to wastewater samples taken at the individual passive sampling point. Our results show that passive samplers can indicate at a city-scale level an accurate level of positive infections in the population (positive-rate: 86 %). On a small-scale level, the use of passive samplers was also feasible and effective to detect SARS-CoV-2 GC easily and cost-effectively, mirroring a similar trend to that at a city-scale level. Thus, this study demonstrated that passive samplers provide reproducible SARS-CoV-2 GC signals from wastewater and a time-integrated measurement of the sampled matrix with greater sensitivity compared to wastewater. We thus recommend the use of passive samplers as an alternative method for wastewater-based epidemiology. Passive samplers can in particular be considered for a better estimation of infections compared to incidence levels.

Effects of sewage sludge hydrochar on emissions of the climate-relevant trace gases N2O and CO2 from loamy sand soil

This work explores the effects of amending a loamy sand soil with hydrochars having different physicochemcial characteristics. The effects of different hydrochars on emissions of the greenhouse gases nitrous oxide (N₂O) and carbon dioxide (CO₂) were investigated together with the relationship between the hydrochar's mineral nitrogen content and the soil microbial biomass. Soil samples were amended with eleven different hydrochars and feedstocks having different carbon and nitrogen contents at application rates of 5 t ha^-1 and 25 t ha^-1. Microbial immobilization was the main mineral nitrogen sink in soil following hydrochar application. Moreover, the processing conditions applied during hydrochar production (i.e., the pyrolysis temperature and residence time) had significant effects on N₂O and CO₂ emissions: treatment with incubated hydrochars yielded significantly lower N₂O emissions than treatment with non-carbonized feedstocks, particularly at the highest level of hydrochar application (25 t ha^-1). Further analysis revealed that increasing the process temperature and residence time during hdyrochar production significantly increased the final product's total organic carbon content but reduced its content of hot water extractable carbon. Hydrochars produced with higher process temperatures and longer residence times therefore yielded lower CO₂ emissions during a 44-day incubation experiment than raw feedstocks or hydrochars produced under less severe conditions. Hydrochars formed from sewage sludge at high process temperatures and with long residence times are thus promising soil additives for reducing GHG emissions.

Simultaneous removal of rotavirus and adenovirus from artificial ground water using hydrochar derived from swine feces

Hydrothermal carbonization technology can convert fecal waste into a valuable carbonaceous product referred to as hydrochar. We investigated the potential of fecal waste-derived hydrochar as an adsorbent for virus removal in water treatment. Swine feces was hydrothermally treated under two conditions: at 180 °C for 2 h and 230 °C for 7 h. The resulting solid products (hydrochar) were evaluated as virus adsorbents in water treatment. Simultaneous removal of pathogenic rotavirus (RV) and human adenovirus (HAdV) was investigated using a sand column set-up of 10 cm bed height with and without hydrochar supplement (1.5%, w/w). The removal efficiency of both viruses in a hydrochar-amended column was >3 log (complete removal). The amount of virus released in deionized water when flushed into the virus-retaining columns indicated that the secondary energy minimum played a more important role in RV retention than that of HAdV. Zeta-potential and hydrophobicity measurements on hydrochar materials indicated that the improved virus removal performance of hydrochar-amended columns was induced by the provision of extra hydrophobic surfaces. This study provides evidence that fecal waste-derived hydrochar can be used as a competent virus adsorbent.

Carbon storage potential in size-density fractions from semi-natural grassland ecosystems with different productivities over varying soil depths

Researchers have increasingly recognised a profound need for more information on SOC stocks in the soil and the factors governing their stability and dynamics. Many questions still remain unanswered about the interplay between changes in plant communities and the extent to which changes in aboveground productivity affect the carbon dynamics in soils through changes in its quantity and quality. Therefore, the main aim of this research was to examine the SOC accumulation potential of semi-natural grasslands of different productivities and determine the distribution of SOM fractions over varying soil depth intervals (0-10, 10-20, 20-30 30-50 50-80 and 80+cm). SOM fractionation was considered as a relative measure of stability to separate SOM associated with clay minerals from SOM of specific light densities less than 2 g cm(-3) (size-density fractionation). Two clay-associated fractions (CF1, <1 μm; and CF2, 1-2 μm) and two light fractions (LF1, <1.8 g cm(-3); and LF2, 1.8-2.0 g cm(-3)) were separated. The stability of these fractions was characterised by their carbon hot water extractability (CHWE) and stable carbon isotope composition. In the semi-natural grasslands studied, most OC was stored in the top 30 cm, where turnover is rapid. Effects of low productivity grasslands became only significantly apparent when fractional OC contributions of total SOM was considered (CF1 and LF1). In deeper soil depths OC was largely attributed to the CF1 fraction of low productivity grasslands. We suggest that the majority of OM in deeper soil depth intervals is microbially-derived, as evidenced by decreasing C/N ratios and decreasing δ(13)C values. The hot water extraction and natural δ(13)C abundance, employed here allowed the characterisation of SOM stabilisation properties, however how climatic changes affect the fate of OM within different soil depth intervals is still unknown.

Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

Microorganisms are vital in mediating the earth's biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: 'When do we need to understand microbial community structure to accurately predict function?' We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.

Short-term bioavailability of carbon in soil organic matter fractions of different particle sizes and densities in grassland ecosystems

The quality, stability and availability of organic carbon (OC) in soil organic matter (SOM) can vary widely between differently managed ecosystems. Several approaches have been developed for isolating SOM fractions to examine their ecological roles, but links between the bioavailability of the OC of size-density fractions and soil microbial communities have not been previously explored. Thus, in the presented laboratory study we investigated the potential bioavailability of OC and the structure of associated microbial communities in different particle-size and density fractions of SOM. For this we used samples from four grassland ecosystems with contrasting management intensity regimes and two soil types: a Haplic Cambisol and a typical Chernozem. A combined size-density fractionation protocol was applied to separate clay-associated SOM fractions (CF1, <1 μm; CF2, 1-2 μm) from light SOM fractions (LF1, <1.8 g cm(-3); LF2, 1.8-2.0 g cm(-3)). These fractions were used as carbon sources in a respiration experiment to determine their potential bioavailability. Measured CO2-release was used as an index of substrate accessibility and linked to the soil microbial community structure, as determined by phospholipid fatty acids (PLFA) analysis. Several key factors controlling decomposition processes, and thus the potential bioavailability of OC, were identified: management intensity and the plant community composition of the grasslands (both of which affect the chemical composition and turnover of OC) and specific properties of individual SOM fractions. The PLFA patterns highlighted differences in the composition of microbial communities associated with the examined grasslands, and SOM fractions, providing the first broad insights into their active microbial communities. From observed interactions between abiotic and biotic factors affecting the decomposition of SOM fractions we demonstrate that increasing management intensity could enhance the potential bioavailability of OC, not only in the active and intermediate SOM pools, but also in the passive pool.

[Recombinant tissue-type plasminogen activator for the emergency treatment of perioperative life-threatening pulmonary embolism (stage IV). Results in 7 patients]

We report a series of seven patients (age: 43-77 years, preoperative American Society of Anesthesiologists (ASA) physical status II-III) with perioperative, life-threatening pulmonary embolism and severe cardiogenic shock treated with recombinant tissue type plasminogen activator (rt-PA). Diagnosis was established by ECG (n = 7), arterial blood gas analysis (n = 7), massive elevation of mean pulmonary arterial pressure (MPAP: 40 +/- 6 mmHg SD, n = 7), echocardiography (n = 3), increased arterial/end-tidal CO2 difference (30 +/- 16 mmHg, n = 3), and pulmonary angiography (n = 4). All patients had to be ventilated, six with an FIO2 of 1.0. To achieve a mean arterial pressure of above 60 mmHg all patients received norepinephrine 0.4 +/- 0.2 microgram.kg-1.min-1 in combination with dopamine 11 +/- 5 micrograms.kg-1.min-1 (n = 6), epinephrine 0.13 +/- 0.04 microgram.kg-1.min-1 (n = 5) or dobutamine 14 +/- 6 micrograms.kg-1.min-1 (n = 3). In addition, six of seven patients had to be resuscitated by external chest compression (duration of resuscitation: 5 to 40 min) prior to or during the thrombolytic therapy. The dosages of rt-PA ranged from 10 to 150 mg, and the duration of administration up to 31 h. Six patients survived neurologically intact. In these six patients MPAP had decreased from 41 +/- 6 mmHg to 33 +/- 6 mmHg (P less than 0.05, Wilcoxon rank test) 2 h after the start of thrombolytic therapy, with concomitant reduction of vasopressor and inotropic support.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment of massive pulmonary embolism with recombinant tissue type plasminogen activator (rt-PA) in a pregnant woman with intact gravidity and preterm labour

We report a patient with massive pulmonary embolism and circulatory shock during pregnancy (31st gestational week) and preterm labour who has been successfully treated with recombinant tissue type plasminogen activator. Thrombolysis was performed using 10 mg.h-1 over 4 h followed by 2 mg.h-1 for 1 h 30 min resulting in complete resolution of cardio-respiratory symptoms. Except for slight bleeding from one puncture site no complications occurred. At 48 h after the end of thrombolytic therapy the patient was delivered spontaneously of a male preterm healthy infant. The relevance of this new thrombolytic agent in the treatment of massive life-threatening pulmonary embolism during pregnancy is discussed.

[A successful lytic treatment of a perioperative pulmonary embolism necessitating resuscitation using recombinant tissue-type plasminogen activator]

We report a patient with massive perioperative pulmonary embolism (stage IV) and cardiac arrest who was successfully treated with recombinant tissue plasminogen activator (rt-PA). Thrombolytic therapy was started with 25 mg rt-Pa over 15 min followed by another 25 mg over 45 min. During the next 5 h 50 mg were infused, and thereafter an additional 50 mg over 24 h. No major alterations in the plasmatic coagulation profile were noted. With the exception of moderate blood loss from one puncture site, no further bleeding complications occurred. The relevance of this new thrombolytic agent in the perioperative management of acute, life-threatening pulmonary embolism is discussed.

Extracorporeal CO2-removal with a heparin coated artificial lung

Treatment of severe acute respiratory failure with extracorporeal gas exchange necessitating near complete systemic anticoagulation requires a delicate balance to be maintained between disseminated intravascular coagulation and hemorrhagic complications. The present study describes our first experience using a heparin coated extracorporeal artificial lung and circuitry during clinical extracorporeal CO2 removal. In spite of a partial thromboplastin time and activated clotting time within or close to the normal range, neither laboratory evidence for disseminated intravascular coagulation induced by the extracorporeal circuit nor thrombi in the pulmonary vasculature were found. Scanning electron microscopy of the heparin coated hollow fiber gas exchanger demonstrated only minor deposits on the surface. Use of a heparin coated artificial lung may enhance the margin of safety of extracorporeal gas exchange and ultimately broaden its indications.

Prolonged extracorporeal CO2-removal in severe adult respiratory distress syndrome. Neuropathological observations in two cases

Extracorporeal CO2-removal (EC-CO2-R) using a membrane lung system was applied for 12 and 20 days respectively in two young men with adult respiratory distress syndrome (ARDS). Neuropathological examination revealed only moderate hypoxic changes of unusual distribution. In the first case nerve cell loss in Sommer's sector of the hippocampus and focal incomplete necroses in both putamina were interpreted as the result of cardiac arrest at the onset of the disease rather than of chronic hypoxia. Findings in the second case were confined to nerve cell necroses of a minor degree in the cerebral cortex. Remarkably, the cerebellum was spared in both cases. Our observations suggest that EC-CO2-R was not associated with neuropathological findings which could be attributed specifically to this procedure.

[Pulmonary function during a 10-day successful extracorporeal CO2 elimination in acute respiratory failure. Case report]

Extracorporeal CO2-removal (ECCO2-R) with low-frequency positive-pressure ventilation (LFPPV) may relieve the acutely injured lung from the burden and the risks of excessively high ventilatory minute volumes and airway pressures. It was the purpose of this study to document the evolution of lung function during clinical ECCO2-R with special emphasis on extravascular lung water. ECCO2-R was applied in a 21-year-old female patient suffering from severe post-traumatic infectious adult respiratory distress syndrome. The indication for ECCO2-R was based on the following findings: total static lung compliance 25 cm X cm H2O-1; arterial pO2 50 mm Hg with an inspiratory oxygen concentration of 100%; intrapulmonary right-to-left shunt over 50% of the cardiac output; and extravascular lung water 24 ml X kg-1 (normal 4.5-7 ml X kg-1). ECCO2-R was shown to provide satisfactory conditions for improving the above-mentioned abnormal parameters of pulmonary function. Pressure-limited low-frequency mechanical ventilation allowed successful management of several pneumothoraces with bronchopleural fistulas which occurred during the procedure. It is concluded that these complications of positive airway pressure would have led to the patient's death under the conditions of conventional mechanical ventilation.

[Plasma level of etidocaine within the first two hours after axillary plexus block in healthy adults and patients with renal insufficiency (author's transl)]

The plasma level of etidocaine was studied within the first two hours of axillary block in 7 patients with renal insufficiency and 7 healthy adults. After 15-20 min the maximum of plasma concentration was found in the group with renal failure and after 30-45 min in the healthy adults. 30 min after the block the plasma level was 1,26 +/- 0,62 mug/ml in the ill patients and only 0,73 +/- 0,31 in the normal group. Using a mathematical model the ratio of permeation into the blood is significantly higher in the group with renal failure than in the healthy adults. The main reason for these results seems to be the acidosis, which is often combined with renal insufficiency. The meaning of these results for regional anaesthesia in patients like these is discussed.