Objective: The most common methods to calculate energy costs are based on measured oxygen uptake during walking a standardized distance or time. Unfortunately, it is unclear which method is most reliable to determine energy cost of walking in stroke survivors. The objective of this study was to evaluate the 3 most commonly used methods for calculating oxygen consumption and -cost by assessing test-retest reliability and measurement error in community dwelling chronic stroke survivors during a 6 Minute Walk Test. Methods: In this secondary analysis of a longitudinal study, reproducibility of the outcome of walking distance, walking speed, oxygen consumption and oxygen cost from 3 methods (Kendall's tau, assumed steady-state and total walking time oxygen consumption) were determined using Intraclass Correlation Coefficient, Standard Error of Measurement and Smallest Detectable Change. Results: 20 from the 31 participants successfully performed the 6 minute walk test-retest within a timeframe of 1 month. Within the 2 tests the reproducibility of walking distance and walking speed was high. The 3 methods to determine reproducibility for oxygen cost and oxygen consumption were considered good (Kendall's tau), good (assumed steady-state) and excellent (total walking time). Conclusions: The method using oxygen consumption and -cost over the total walking time resulted in the highest reproducibility considering the Intraclass Correlation Coefficient, its 95% Confidence Interval, and smaller absolute differences.
LINK
The COVID–19 pandemic led to local oxygen shortages worldwide. To gain a better understanding of oxygen consumption with different respiratory supportive therapies, we conducted an international multicenter observational study to determine the precise amount of oxygen consumption with high-flow nasal oxygen (HFNO) and with mechanical ventilation. A retrospective observational study was conducted in three intensive care units (ICUs) in the Netherlands and Spain. Patients were classified as HFNO patients or ventilated patients, according to the mode of oxygen supplementation with which a patient started. The primary endpoint was actual oxygen consumption; secondary endpoints were hourly and total oxygen consumption during the first two full calendar days. Of 275 patients, 147 started with HFNO and 128 with mechanical ventilation. Actual oxygen use was 4.9-fold higher in patients who started with HFNO than in patients who started with ventilation (median 14.2 [8.4–18.4] versus 2.9 [1.8–4.1] L/minute; mean difference 5 11.3 [95% CI 11.0–11.6] L/minute; P, 0.01). Hourly and total oxygen consumption were 4.8-fold (P, 0.01) and 4.8-fold (P, 0.01) higher. Actual oxygen consumption, hourly oxygen consumption, and total oxygen consumption are substantially higher in patients that start with HFNO compared with patients that start with mechanical ventilation. This information may help hospitals and ICUs predicting oxygen needs during high-demand periods and could guide decisions regarding the source of distribution of medical oxygen.
MULTIFILE
The need of an adaptive sustainable solution for the increased land scarcity, growing urbanization, climate change and flood risks resulted in the concept of the floating urbanization. In The Netherlands this new type of housing attracted the interest of local authorities, municipalities and water boards. Moreover, plans to incorporate floating houses in the urban planning have already been developed. However, the knowledge gap regarding the potential effect on the water quality halts the further development of the floating houses. This paper shows the results of a water quality measurement campaign, as part of the national program “Knowledge for climate”, at a small floating houses project in Delft and serves as a case study for addressing the environmental-ecological knowledge gap on this topic.
DOCUMENT
Green methanol is emerging as a key player in sustainable biotech, offering a renewable alternative to fossil fuels or sugar based feedstocks. Although methanol has long been considered a promising material for bioproduction, using it on industrial scale has been challenging due to its high oxygen demands, making the process expensive and inefficient. This project focuses on developing a sustainable, but more economical feasible way to produce biochemicals, like Single Cell Protein (SCP). The innovative solution proposed by FeedstocksUnited (FSU) is to use paraformaldehyde, a compound derived from renewable methanol, as feedstock, which requires much less oxygen during fermentation. This new method has already shown promising results in the lab, where it was tested with microorganisms that can use formaldehyde (released from paraformaldehyde) as a source of carbon and energy. FSU’s approach has the potential to significantly reduce the costs and environmental impacts associated with large-scale bioproduction. The process can be managed more efficiently than methods using methanol, since the production of paraformaldehyde from formaldehyde is tunable. This process control will lead to better yields and reduced energy and feedstock consumption. The HAN BioCentre, with its advanced research facilities and experienced team, will conduct further research to optimize this method for industrial applications. This includes studying how organisms metabolize formaldehyde and improving the process through continuous fermentation. The research also supports educational goals by involving students in cutting-edge biotechnological work. Ultimately, the project aims to provide a solid proof-of-concept that can be scaled up to industrial levels, contributing to a more sustainable bioeconomy.
The EU Climate and Energy Policy Framework targets a 40% reduction in Greenhouse Gases (GHGs) emission by companies (when compared to 1990’s values) in 2030 [1]. Preparing for that future, many companies are working to reach climate neutrality in 2030. For water and wastewater treatment plants aeration processes could represent up to 70% of the whole energy consumption of the plant. Thus, a process which must be carefully evaluated if climate neutrality is a target. VortOx is an alternative to reduce power consumption in aeration processes. It is structured to test the applicability of geometrically constrained vortices in a hyperbolic funnel (aka “Schauberger”- funnel) as an innovative aeration technique for this industry. Recent investigations have shown that such systems allow an average of 12x more oxygen transfer coefficients (KLa) than that of comparable methods like air jets or impellers [10]. However, the system has a relatively small hydraulic retention time (HRT), which compromises its standard oxygen transfer ratio (SOTR). Additionally, so far, the system has only been tested in pilot (lab) scale. Vortox will tackle both challenges. Firstly, it will test geometry and flow adaptations to increase HRT keeping the same KLa levels. And secondly, all will be done using a real scale hyperbolic funnel and real effluent from Leeuwarden’s wastewater treatment plant demo-site. If proven feasible, Vortox can be a large step towards climate neutral water and wastewater treatment systems.
