The Benefit of Thrombectomy in Patients With Low ASPECTS Is a Matter of Shades of Gray—What Current Trials May Have Missed

Randomized trials supporting the benefit of endovascular treatment in acute ischemic stroke patients with a large early infarction are not yet available. Few retrospective studies exist that suggest a potential positive treatment effect on functional outcome, as well as procedural safety. However, potential benefit or harm of MT in patients with low initial ASPECTS is still a subject of current debate, and in particular, how to select these patients for treatment. The purpose of this pilot study was to evaluate how early tissue water uptake in acute ischemic brain might determine lesion fate and functional outcome in low ASPECTS patients undergoing MT. We observed that the degree of early water uptake measured by quantitative NWU was significantly associated with functional outcome in low ASPECTS patients, yielding a higher diagnostic power compared to other parameters such as ASPECTS, age, or NIHSS. No conclusive evidence of a beneficial effect of successful reperfusion was observed in patients with low ASPECTS and high NWU, which highlights the potential of NWU as a tool to specify patient selection.

Wettability and Water Uptake Improvement in Plasma-Treated Alfalfa Seeds

The cultivation of alfalfa (Medicago sativa L.), a forage crop grown worldwide, is negatively affected by hard seed presence. We show that treatment of alfalfa seeds with an inductively coupled radio frequency oxygen plasma improves their surface hydrophilicity, as determined by water contact angle (WCA) measurements and water uptake. Furthermore, we see that these effects are mediated by functionalization and etching of the alfalfa seed surface. Surface chemistry is analyzed by X-ray photoelectron spectroscopy (XPS), while morphology is viewed using scanning electron microscopy (SEM). Plasma produces effective alfalfa seed hydrophilization with a variety of treatment parameters. With its potential for fine-tuning, plasma modification of seed wettability shows promise for introduction into agricultural practice.

The Effect of Sulfated Zirconia and Zirconium Phosphate Nanocomposite Membranes on Fuel-Cell Efficiency

To investigate the effect of acidic nanoparticles on proton conductivity, permeability, and fuel-cell performance, a commercial Nafion® 117 membrane was impregnated with zirconium phosphates (ZrP) and sulfated zirconium (S-ZrO2) nanoparticles. As they are more stable than other solid superacids, sulfated metal oxides have been the subject of intensive research. Meanwhile, hydrophilic, proton-conducting inorganic acids such as zirconium phosphate (ZrP) have been used to modify the Nafion® membrane due to their hydrophilic nature, proton-conducting material, very low toxicity, low cost, and stability in a hydrogen/oxygen atmosphere. A tensile test, water uptake, methanol crossover, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to assess the capacity of nanocomposite membranes to function in a fuel cell. The modified Nafion® membrane had a higher water uptake and a lower water content angle than the commercial Nafion® 117 membrane, indicating that it has a greater impact on conductivity. Under strain rates of 40, 30, and 20 mm/min, the nanocomposite membranes demonstrated more stable thermal deterioration and higher mechanical strength, which offers tremendous promise for fuel-cell applications. When compared to 0.113 S/cm and 0.013 S/cm, respectively, of commercial Nafion® 117 and Nafion® ZrP membranes, the modified Nafion® membrane with ammonia sulphate acid had the highest proton conductivity of 7.891 S/cm. When tested using a direct single-cell methanol fuel cell, it also had the highest power density of 183 mW cm−2 which is better than commercial Nafion® 117 and Nafion® ZrP membranes.

Modelling the gas–particle partitioning and water uptake of isoprene-derived secondary organic aerosol at high and low relative humidity

This study presents a characterization of the hygroscopic growth behaviour and effects of different inorganic seed particles on the formation of secondary organic aerosols (SOAs) from the dark ozone-initiated oxidation of isoprene at low NOx conditions. We performed simulations of isoprene oxidation using a gas-phase chemical reaction mechanism based on the Master Chemical Mechanism (MCM) in combination with an equilibrium gas–particle partitioning model to predict the SOA concentration. The equilibrium model accounts for non-ideal mixing in liquid phases, including liquid–liquid phase separation (LLPS), and is based on the AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients) model for mixture non-ideality and the EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects) model for pure compound vapour pressures. Measurements from the Cosmics Leaving Outdoor Droplets (CLOUD) chamber experiments, conducted at the European Organization for Nuclear Research (CERN) for isoprene ozonolysis cases, were used to aid in parameterizing the SOA yields at different atmospherically relevant temperatures, relative humidity (RH), and reacted isoprene concentrations. To represent the isoprene-ozonolysis-derived SOA, a selection of organic surrogate species is introduced in the coupled modelling system. The model predicts a single, homogeneously mixed particle phase at all relative humidity levels for SOA formation in the absence of any inorganic seed particles. In the presence of aqueous sulfuric acid or ammonium bisulfate seed particles, the model predicts LLPS to occur below ∼ 80 % RH, where the particles consist of an inorganic-rich liquid phase and an organic-rich liquid phase; however, this includes significant amounts of bisulfate and water partitioned to the organic-rich phase. The measurements show an enhancement in the SOA amounts at 85 % RH, compared to 35 % RH, for both the seed-free and seeded cases. The model predictions of RH-dependent SOA yield enhancements at 85 % RH vs. 35 % RH are 1.80 for a seed-free case, 1.52 for the case with ammonium bisulfate seed, and 1.06 for the case with sulfuric acid seed. Predicted SOA yields are enhanced in the presence of an aqueous inorganic seed, regardless of the seed type (ammonium sulfate, ammonium bisulfate, or sulfuric acid) in comparison with seed-free conditions at the same RH level. We discuss the comparison of model-predicted SOA yields with a selection of other laboratory studies on isoprene SOA formation conducted at different temperatures and for a variety of reacted isoprene concentrations. Those studies were conducted at RH levels at or below 40 % with reported SOA mass yields ranging from 0.3 % up to 9.0 %, indicating considerable variations. A robust feature of our associated gas–particle partitioning calculations covering the whole RH range is the predicted enhancement of SOA yield at high RH (> 80 %) compared to low RH (dry) conditions, which is explained by the effect of particle water uptake and its impact on the equilibrium partitioning of all components.

Use of Hemp Fibres in 3D Printed Concrete

The use of fibres as reinforcement of 3D printed concrete is widely known and applicable in many situations. However, most of the applied fibres are not produced from renewable resources. Natural fibres are commonly considered as an ecological alternative for these fibres. In order to contribute to improvement of the sustainability of 3D printed concrete, natural fibres such as hemp can replace these synthetic fibres. The objective of this study is therefore to study the possibilities of adding hemp fibres for 3D printing purposes. Due to the comparable properties of hemp and synthetic fibres, natural fibres tend to be suitable for printing purposes. Mixes are made at laboratory scale using batches of 1 – 3 kg. The study examines the effect of adding hemp fibres for the mechanical and fresh state properties of hemp-based concrete. Mechanical properties from bending tests and direct tensile tests show comparable properties of mortars containing hemp fibres and mortars containing synthetic fibres. The fresh state behaviour of the designed concrete mix showed promising and comparable results for a mix based on 0.5wt% of hemp fibres. One of the major issues regarding the use of natural fibres is the irregularity and high water uptake of the fibres. Due to its high hydrophilicity natural hemp fibres take up much water and can therefore degrade. For this study the effect of water uptake did not have much influence on the mixing and printing purposes. By printing a wall element on laboratory scale the use of hemp fibre-reinforced 3D concrete is validated.

Modelling the artificial forest (<i>Robinia pseudoacacia</i> L.) root–soil water interactions in the Loess Plateau, China

Plant root–soil water interactions are fundamental to vegetation–water relationships. Soil water availability and distribution impact the temporal–spatial dynamics of roots and vice versa. In the Loess Plateau (LP) of China, where semi-arid and arid climates prevail and deep loess soil dominates, drying soil layers (DSLs) have been extensively reported in artificial forestland. While the underlying mechanisms that cause DSLs remain unclear, they hypothetically involve root–soil water interactions. Although available root growth models are weak with respect to simulating the rooting depth, this study addresses the hypothesis of the involvement of root–soil water interactions in DSLs using a root growth model that simulates both the dynamic rooting depth and fine-root distribution, coupled with soil water, based on cost–benefit optimization. Evaluation of field data from an artificial black locust (Robinia pseudoacacia L.) forest site in the southern LP positively proves the model's performance. Further, a long-term simulation, forced by a 50-year climatic data series with varying precipitation, was performed to examine the DSLs. The results demonstrate that incorporating the dynamic rooting depth into the current root growth models is necessary to reproduce soil drying processes. The simulations revealed that the upper boundary of the DSLs fluctuates strongly with infiltration events, whereas the lower boundary extends successively with increasing rooting depth. Most infiltration was intercepted by the top 2.0 m layer, which was the most active zone of infiltration and root water uptake. Below this, the percentages of fine roots (5.0 %) and water uptake (6.2 %) were small but caused a persistently negative water balance and consequent DSLs. Therefore, the proposed root–water interaction approach succeeded in revealing the intrinsic properties of DSLs; their persistent extension and the lack of an opportunity for recovery from the drying state may adversely affect the implementation of artificial afforestation in this region as well as in other regions with similar climates and soils.

Optimizing Water Consumption in Richards’ Equation Framework with Step-Wise Root Water Uptake: A Simplified Model

This work arises from the need of exploring new features for modeling and optimizing water consumption in irrigation processes. In particular, we focus on water flow model in unsaturated soils, accounting also for a root water uptake term, which is assumed to be discontinuos in the state variable. We investigate the possibility of accomplishing such optimization by computing the steady solutions of a $$\theta$$ θ -based Richards equation revised as equilibrium points of the ODEs system resulting from a numerical semi-dicretization in the space; after such semi-discretization, these equilibrium points are computed exactly as the solutions of a linear system of algebraic equations: the case in which the equilibrium lies on the threshold for the uptake term is of particular interest, since the system considerably simplifies. In this framework, the problem of minimizing the water waste below the root level is investigated. Numerical simulations are provided for representing the obtained results. Article Highlights Root water uptake is modelled in a Richards’ equation framework with a discontinuous sink term. After a proper semidiscretization in space, equilibrium points of the resulting nonlinear ODE system are computed exactly. The proposed approach simplifies a control problem for optimizing water consumption.

An efficient composite membrane to improve the performance of PEM reversible fuel cells

The aim of this study is to develop composite Nafion/GO membranes, varying GO loading, to be used in a Unitized reversible fuel cell comparing its performance with the baseline Nafion. Water uptake, ion exchange capacity (IEC), tensile strength, and SEM (scanning electron microscope) analysis are discussed. The SEM analysis revealed how the GO is homogeneously disposed into the Nafion matrix. The addition of GO improves the membrane tensile strength while reducing the elongation ratio. Water uptake, IEC enhance with the increasing of GO content. Regarding fuel cell mode, the performance is analysed using a polarization curve on a MEA with an effective area of 9 cm2. The composite membrane demonstrated higher mechanical strength, enhanced water uptake so higher performance in fuel cell mode. Despite the power absorbed from the electrolysis is higher when using a composite membrane, the beneficial effect in FC mode resulted in a slightly higher round trip efficiency. The GO-Nafion membrane was not able to maintain its performance with increasing the operating time, so potentially leading to a lower lifetime than the Nafion bare.