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The Integration of Hydrological and Heat Exchange Processes Improves Stream Temperature Simulations in an Ecohydrological Model
Full text linkStream temperature is among the main drivers affecting water quality by influencing chemical reaction rates and biological activity. Due to globally rising air temperatures, increased stream temperatures are equally rising and becoming more relevant for ecosystem health. Stream temperature is influenced by a complex interplay of climate, hydrological processes and catchment characteristics. However, these process interactions are often overlooked when being integrated with hydrological models. This study addresses the limitations of a simplified stream temperature model by using the ecohydrological model Soil and Water Assessment Tool (SWAT+). Our goal was to enhance the process representation in the current stream temperature model by refining the mass transfer processes. We included heat transfer processes improved by a channel shape parameter, and the influence of riparian shading with an improved equation to simplify the modified dew point temperature calculation. The enhanced SWAT+ model was tested at 23 stations in a medium-sized mountainous catchment with high-resolution observed stream temperature data. Our results show that the enhanced model significantly improved performance, achieving a mean Kling–Gupta Efficiency (KGE) of 0.8 across all calibration sites. We improved previous advances in stream temperature modelling within this work by focussing on the importance of accurate process representation. A key finding was the impact of runoff component contributions on the stream temperature model performance. The model performed particularly well during spring, autumn and very low to moderate flows. The improved stream temperature representation therefore not only serves as a valuable tool for management decisions and ecological applications but also benefits modelling other water quality variables
A Yeast‐Based Assay for Inhibitors of l‐Lactate Transport Utilizing Fluorescent Biosensors
Full text linkInhibitors of ʟ-lactate transport are in development as a novel mode of action in antitumor therapy and malaria. Previously, we used radiolabeled ʟ-lactate to assay transport via the human monocarboxylate transporter 1, MCT1, and the structurally unrelated malaria parasite's transporter, PfFNT. We encountered a sensitivity limit at IC50 around 100 nM possibly resulting from the required high cell number per sample. Here, we describe a sensitive background-free high-throughput assay in yeast based on fluorescent iLACCO biosensors. We used iLACCO for co-expression and fusions with the transporter protein. Uptake of ʟ-lactate produced strong intensiometric fluorescent responses that could be monitored in cell suspensions using a fluorometer and in individual cells by fluorescence microscopy. The signal decreased dose-dependently in the presence of specific MCT1 and PfFNT inhibitors. Re-evaluation of 36 PfFNT inhibitors yielded IC50 values below 100 nM now matching previous data on Ki compound affinity to isolated transporter protein
Alpine Crust and Mantle Structure From 3D Monte Carlo Surface‐ and Body‐Wave Tomography
Full text linkAn ongoing controversy revolves around the detailed structure of the subducting European and Adriatic plates under the Alps and the adjacent orogens. Mostly based on P‐wave travel time tomographic images, slab break‐off at different times, reversals of subduction polarity and segmentation of the slab into independent units have been proposed. These processes may have important geodynamic consequences such as rapid surface uplift, past magmatic events or changes in the style of continental collision. However, some of the tomographic results are contradictory, particularly evident in the uppermost mantle where teleseismic P waves traverse the medium almost vertically with few ray crossings and a stronger dependence on the crustal correction. In this work, we present the result of an innovative joint inversion approach using surface‐ and teleseismic body‐wave travel times to mitigate some of the shortcomings in both data types. Applying a reversible‐jump Markov chain Monte Carlo approach, we simultaneously constrain the vP and vS structure and their uncertainties in the crust and upper mantle. The results indicate a continuous slab structure from the crust‐ mantle boundary down to at least 400 km depth under the western, central and eastern Alps. The results, however, also suggest that fitting the data within their respective measurement uncertainties may not be sufficient to reliably determine the presence of a shallow slab break‐off beneath the Alp
Understanding Social Structural Change: Change Agency, Mediated Dualism and Fragmented Habitus
Full text linkAgency plays a crucial role in social and economic change, especially in regional transition processes. Interpreting the influence of context on agency reflects the spatial ontology of economic geography. However, culture, as one dimension of context, is still profoundly limitedly understood within economic geography. For instance, it is often constrained to tangible cultural heritage or formal institutions. Moreover, individual-level agency has remained understudied, especially how individuals develop their capacity to act, since it is challenging to distinguish individual and their position within in/formal organizations. Here, we suggest addressing these limitations by integrating Bourdieu's notion of habitus, which contributes to transcending the dichotomies between materials and culture and between structuralism and individualism. Hence, the primary objectives of this paper are as follows: (1) to undertake a comprehensive review of habitus from broader social sciences, in particular to explain the mediated dualism of habitus; (2) to respond to the criticism that habitus is a static concept, and to explain the potential to investigate change; (3) to explicate how agency interacts with habitus. Finally, we recommend economic geographers to integrate fragmented habitus with agency to study social structural change, thereby enriching the discipline's comprehension of context
Dynamic and Reversible Tuning of Hydrogel Viscoelasticity by Transient Polymer Interactions for Controlling Cell Adhesion
Full text linkCells are highly responsive to changes in their mechanical environment, influencing processes such as stem cell differentiation and tumor progression. To meet the growing demand for materials used for high throughput mechanotransduction studies, simple means of dynamically adjusting the environmental viscoelasticity of cell cultures are needed. Here, a novel method is presented to dynamically and reversibly control the viscoelasticity of naturally derived polymer hydrogels through interactions with poly (ethylene glycol) (PEG). Interactions between PEG and hydrogel polymers, possibly involving hydrogen bonding, stiffen the hydrogel matrices. By dynamically changing the PEG concentration of the solution in which polymer hydrogels are incubated, their viscoelastic properties are adjusted, which in turn affects cell adhesion and cytoskeletal organization. Importantly, this effects is reversible, providing a cost-effective and simple strategy for dynamically adjusting the viscoelasticity of polymer hydrogels. This method holds promise for applications in mechanobiology, biomedicine, and the life sciences
An Established Plant Invader May Still Benefit From Increasing Genetic Diversity-Insights From Artificial Populations in a Common Garden Experiment
Full text linkGenetic diversity and competitive ability, though extensively studied in the context of biological invasions, are still poorly understood in their relative importance, especially when shifting the perspective from an individual plant's phenotype to overall population performance. We determined pairwise genetic distances among 16 invasive and 22 native populations of Jacobaea vulgaris GAERTN. using single nucleotide polymorphisms (SNP). Based on this information, we created each 15 de-novo populations with different levels of genetic diversity for both origins. These de-novo populations were subjected to three levels of decreasing microsite availability by using a matrix of either 0, 5, or 10 individuals of Festuca rubra. We monitored population performance continuously throughout two growing seasons to study effects of interactions between origin, microsite availability, and genetic diversity with (generalized) linear effects models. This allowed us to uncover whether the relative importance of those factors varies with the life-stage of this biennial species. We found no ambiguous patterns on the hypothesized beneficial effect of genetic diversity for J. vulgaris populations. Native populations tended to respond negatively to increasing genetic diversity, especially under more favorable site conditions, but this was not a persistent pattern and was only evident through continuous monitoring. Invasive populations could benefit from increasing genetic diversity during early establishment, but not in interaction with restricted microsite availability. Our results do suggest that genetic variation supports population establishment and performance under certain environmental conditions. Therefore, for recommendations in nature conservation, efforts should still aim at limiting propagule addition in already invaded areas, even in well-established invasive species
A Perceptual Model of Drivers and Limiters of Coastal Groundwater Dynamics
Full text linkCoastal groundwater is a vital resource for coastal communities around the globe, and submarine groundwater discharge (SGD) delivers nutrients to coastal marine ecosystems. Climatic changes and anthropogenic actions alter coastal hydrology, causing seawater intrusion (SWI) globally. However, the selection of SWI and SGD study sites may be highly biased, limiting our process knowledge. Here, we analyse hydroenvironmental characteristics of coastal basins studied in 1298 publications on SGD and SWI to understand these potential biases. We find that studies are biased towards basins with gross domestic product per capita below (SWI) and above (SGD) the median of all global coastal basins. Urban coastal basins are strongly overrepresented compared to rural coastal basins, limiting our progress in understanding undisturbed natural processes. Despite the connection between anthropogenic activity and coastal groundwater issues, and the consequential overrepresentation of urban basins in coastal groundwater studies, perceptual (or conceptual) models of coastal groundwater rarely include anthropogenic influences aside from pumping (e.g., subsidence, land use change). Taking a holistic view on coastal groundwater flows, we have developed an editable perceptual model illustrating the current understanding, including both natural and anthropogenic drivers. As SGD and SWI in new areas of the globe are studied, we advocate for researchers to utilise and further edit this perceptual model to openly communicate our process understanding and study assumptions
Unraveling the Stereoisomer Configurations of 1,1’‐bis(tert‐butylphosphino)Ferrocene in the Gas Phase
Full text linkThe molecular structure of a ferrocene derivative with adjacent centers of chirality, 1,1'-bis(tert-butylphosphino)ferrocene, has been examined in the gas phase using broadband microwave spectroscopy under the isolated and cold conditions of a supersonic jet. The diastereomers of 1,1'-bis(tert-butylphosphino)ferrocene can adopt homo- and hetero-chiral configurations, owing to the P-chiral substituents on the cyclopentadienyl rings. Moreover, the internal ring rotation of each diastereomer gives rise to four conformers with eclipsed ring arrangements, where the two tert-butylphosphino groups were separated by dihedral angles of approximately 72°, 144°, 216°, and 288° with respect to the two ring centers. The interconversion barriers between the conformations are below 2 kJ/mol, whereas the pyramidal inversion of the tert-butylphosphino groups is hindered by more than 140 kJ/mol, calculated at the B3LYP-D3(BJ)/def2-QZVP level of theory. In the experimental microwave spectrum, we unambiguously identified the two global-minimum diastereomers with 72° conformations. The absence of other conformers can be attributed to the relaxation dynamics in the supersonic jet, which transfers the high-energy conformers to the respective global-minimum geometries. Additionally, we discovered that London dispersion interactions between the two tert-butylphosphino groups play a crucial role in stabilizing the structures of this ferrocene complex
Investigation on the formation of two dimensional perovskite nanostructures at the water surface through self initiated reaction
Full text linkThe emerging class of hybrid organic-inorganic perovskites (HOIPs) has exhibited fascinating properties for a wide range of technological applications. With halide ions, HOIPs have provided novel optoelectronic devices including efficient solar cells and with pseudohalide anions-like formate (HCOO-), enigmatic electromagnetic properties have been obtained in HOIPs. Large-scale synthesis of such 2D HOIP films is of immense importance for the advancement of its application as solar materials. We have shown using in-situ X-ray measurements that the Langmuir monolayer of perovskite can be formed at the air-water interface by spreading stearic acid molecules on the water subphase having (C4H9NH3)2PbBr4 molecules. The 2D lead formate perovskite films are formed at the air-water interface through a self-initiated reaction and the in-situ X-ray scattering and ex-situ Raman spectroscopy measurements revealed this reaction process. The spreading of lipid molecules having positive and negative head-group charges as surfactants over the water surface shows that the formation of perovskite nanofilms at the air-water interface specifically requires the presence of HCOO- head-group of stearic acid. In this room temperature interfacial reaction, formate anions come from the stearic acid monolayer present on the water surface and completely replace bromines in the perovskite present in water subphase to form (BA)2Pb(HCOO)4 at the air-water interface. Our results show an easy route for large-scale synthesis of 2D pseudohalide perovskites
Targeting the PI3K/AKT/mTOR pathway in lung cancer: mechanisms and therapeutic targeting
Full text linkOwing to its high mortality rate, lung cancer (LC) remains the most common cancer worldwide, with the highest malignancy diagnosis rate. The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling (PAM) pathway is a critical intracellular pathway involved in various cellular functions and regulates numerous cellular processes, including growth, survival, proliferation, metabolism, apoptosis, invasion, and angiogenesis. This review aims to highlight preclinical and clinical studies focusing on the PAM signaling pathway in LC and underscore the potential of natural products targeting it. Additionally, this review synthesizes the existing literature and discusses combination therapy and future directions for LC treatment while acknowledging the ongoing challenges in the field. Continuous development of novel therapeutic agents, technologies, and precision medicine offers an increasingly optimistic outlook for the treatment of LC