Water Availability Research Articles

Development of a controlled-release mosquito RNAi yeast larvicide suitable for the sustained control of large water storage containers

Large household water storage containers are among the most productive habitats for Aedes aegypti (Linnaeus, 1762), the primary mosquito vector for dengue and other arboviral pathogens. Increasing concerns for insecticide resistance and larvicide safety are limiting the successful treatment of large household water storage containers, which are among the most productive habitats for Aedes juveniles. The recent development of species-specific RNAi-based yeast larvicides could help overcome these problems, particularly if shelf stable ready-to-use formulations with significant residual activity in water can be developed. Here we examine the hypothesis that development of a shelf-stable controlled-release RNAi yeast formulation can facilitate lasting control of A. aegypti juveniles in large water storage containers. In this study, a dried inactivated yeast was incorporated into a biodegradable matrix containing a mixture of polylactic acid, a preservative, and UV protectants. The formulation was prepared using food-grade level components to prevent toxicity to humans or other organisms. Both floating and sinking versions of the tablets were prepared for treatment of various sized water containers, including household water storage tank-sized containers. The tablets passed accelerated storage tests of shelf life stability and demonstrated up to six months residual activity in water. The yeast performed well in both small and large containers, including water barrels containing 20-1000 larvae each, and in outdoor barrel trials. Future studies will include the evaluation of the yeast larvicide in larger operational field trials that will further assess the potential for incorporating this new technology into integrated mosquito control programs worldwide.

Assessment of climate change impact on meteorological variables of Indravati River Basin using SDSM and CMIP6 models.

Climate change, one of the most pressing issues of the twenty-first century, threatens the long-term stability and short-term variability of water resources. Variations in precipitation and temperature will influence runoff and water availability, creating significant challenges as demand for potable water increases. This study addresses a critical literature gap by employing the Statistical Downscaling Model (SDSM) to downscale Global Climate Model (GCM) outputs for the Indravati River Basin, India. Maximum temperature (Tmax), minimum temperature (Tmin), and precipitation (PCP) were statistically downscaled, improving the spatial resolution of coarse GCM data. The model established strong predictor-predictand relationships, offering enhanced local-scale climate projections for the basin. This work provides critical insights into regional climate change impacts in a previously underexplored area. The study projected the meteorological variables (Tmax, Tmin, and PCP) for Chindnar, Jagdalpur, and Pathagudem stations using four GCMs, namely CanESM5, MPI-ESM1-2-HR, EC-Earth3, and NorESM2-LM for the baseline period (1990-2014). The Correlation Coefficient-values (R-values) range from 0.75 to 0.91 for maximum temperature, 0.85 to 0.96 for minimum temperature, and 0.71 to 0.83 for precipitation were achieved using SDSM. The best-performed MPI-ESM1-2-HR model was used to project maximum temperature, minimum temperature, and precipitation for 2024-2054 (2040s) and 2055-2085 (2070s) under SSP4.5 and SSP8.5 scenarios using SDSM. The downscaled results revealed significant shifts in meteorological patterns, highlighting the basin's sensitivity to different socio-economic pathways and future climate conditions. The percentage monthly, seasonal, and annual variations of Tmax, Tmin, and PCP were analysed based on each scenario and time period to suggest remedial measures for future floods and droughts.

Different dry-wet pulses favor different functional strategies: A test using tropical dry forest tree species

In many terrestrial habitats, plants experience temporal heterogeneity in water availability both at the intra and inter annual scales, creating dry-wet pulse scenarios. This variability imposes two concomitant challenges for plants: surviving droughts and efficiently utilizing water when it becomes available, whose responses are closely interconnected. To date, most studies have focused on the response to drought following static designs that do not consider consequences of repeated transitions from one state to the other. In principle, different dry-wet pulse scenarios among years may differentially affect species performance, plant strategies, and promote coexistence through temporal niche separation. We predicted that short frequent droughts would disfavor drought-avoidant species, as rapid leaf loss and production could disrupt their carbon balance, whereas tolerant species, which maintain carbon gain during droughts, should thrive in such conditions. Prolonged droughts might harm tolerant species by causing severe cavitation. We assessed the survival and growth responses of seedlings from 19 tropical dry forest tree species to simulated natural dry-wet pulse scenarios, examining their relationships with the continuum of species’ functional strategies under field conditions, and used greenhouse experiments to accompany the field experiment. As expected, different dry-wet pulse scenarios favored different plant functional strategies. Contrary to predictions, the most tolerant outperformed the most avoiders under all drought scenarios, while rapid water-exploiters thrived under non-drought conditions. The superiority of tolerant over avoider species was reverted in the greenhouse, suggesting that in addition to physiology, the fate of species may depend on extrinsic factors as natural enemies. The interplay between the marked variability of dry-wet pulse scenarios across the years and the diversity of water use strategies may contribute to species coexistence in the tropical dry forests. This research is relevant in predicting changes in dominant tree species under future climate scenarios characterized by increased temporal variation in water availability.

Building Ethiopia’s food security resilience to climate and hydrological change

Abstract Historically Ethiopia’s food security has been sensitive to climatic variability, but changes in future weather and climate could lead to overall reductions and increased variability in agricultural production, without further adaptation. We present an integrated modelling assessment framework which combines climate, crop, and hydrological modelling to quantify future risks to Ethiopia’s food security. We explore the impacts of 2°C and higher climate change scenarios on water availability and crop yields and simulate how future climate shocks may impact Ethiopia’s food. We consider three adaptations to agricultural management practices (improved seed varieties, increased use of nitrogen fertilizer and supplementary irrigation) and quantify their effectiveness in enhancing the resilience of Ethiopia’s food system to climate and hydrological change by 2050. Results show that, without policy intervention, climate change creates a risk of declining Meher season crop yields across Ethiopia. Under the worst climate change scenario, Teff (-12.0%), barley (-6.7%), and wheat (-4.4%) are projected to have the largest decline in average yields, whilst maize (-0.1%) and sorghum (+0.9%) yields are less impacted thanks to more favourable growing conditions. However, the results also indicate that the adaptation options have a bigger beneficial effect than the climate impact. Of the policies evaluated, improved seeds have a relatively greater effect than increased fertilizer use. Supplementary irrigation could help to mitigate increases in crop water requirements under warmer climate conditions and is most effective in drought prone basins and for drought-vulnerable crops. Overall, the results show that locally relevant agricultural policies are necessary to build Ethiopia’s food system resilience to climate and hydrological change by the mid-century.

Convective Drying with the Application of Ultrasonic Pre-Treatment: The Effect of Applied Conditions on the Selected Properties of Dried Apples

The aim of this study was to evaluate the effect of ultrasound used as a preliminary treatment and drying temperature on the properties of dried apples (var. Golden Delicious). The aim of the work was also to optimise the process in terms of reducing the drying time and obtaining a product with specific properties. The apple tissue was sonicated for various times from 30 to 60 min. Then, the tissue was air-dried with a constant air flow of 55 to 85 °C. The work determined the dry substance content, water activity, colour parameters, content, antioxidant activity, and hygroscopicity of the dried material. The drying kinetics were also analysed. The results showed that the decrease in sonification time increased the dry matter content and reduced water activity. Also, the decrease in drying temperature caused a smaller intake of water and led to a lower hygroscopicity of dried apples. The selected parameters of the process had a positive effect on the preservation of bioactive compounds and led to an increase in antioxidant activity. Experimental results were adapted by a second-order polynomial model, where analysis of variance was utilized to define optimal drying conditions. Therefore, considering the shortest drying time, the lowest colour difference, ΔE, and the highest antioxidant activity, the best condition for the drying of apple tissue can be obtained with the application of 30 min of samples sonication and drying of apples at a temperature of 80.9 °C.

Ecohydrological Response of a Tropical Peatland to Rainfall Changes Driven by Intertropical Convergence Zone Variability

ABSTRACTAimTropical peatlands are globally significant carbon stores, increasingly threatened by human activities and climate change. However, their ecohydrological responses to shifting water availability remain poorly understood. In this study, we investigate the connections between climate change, hydrology and vegetation dynamics in a coastal tropical peatland in Panama, aiming to understand the effects of future drying on peatland dynamics.LocationBocas del Toro, Panama (9°22′54″N, 82°21′59″W).TaxonAngiosperms.MethodsHigh‐resolution multiproxy palaeoecological data, including pollen and plant macrofossils (vegetation), testate amoebae (water‐table depth) and physical peat properties, are used to explore the relationships between climate change, hydrology and vegetation in a coastal tropical peatland over the past 700 years. Downscaled climate simulations are integrated with this process‐based understanding to project the likely future responses of this coastal peatland to climate change.ResultsWe identify a clear connection between precipitation variability, driven by shifts in the Intertropical Convergence Zone and water‐table dynamics, which subsequently influence changes in the peatland vegetation mosaic. Historical drier periods are marked by the expansion of shrub communities into the open peatland plain.Main ConclusionsPalaeoecological studies incorporating climate and hydrological proxies are essential for understanding both recent and future ecohydrological dynamics of tropical peatlands. Our findings suggest that in response to future climate change, water tables will lower and shrub communities will expand due to rising temperatures and reduced precipitation. Additionally, future sea‐level rise, combined with declining rainfall, may result in seawater intrusion and significant vegetation shifts in coastal tropical peatlands.

The effects of coating type and drying temperature on the physicochemical properties of the mixture of lemongrass and apple powdered drinks

Fresh beverages from fruits and herbal plants that contain antioxidants are able to enhance the immunity of the human body. However, such fresh beverage products generally have a short shelf life. As an alternative, the products must be converted into powdered drinks. Coating materials are thus needed to avoid the loss of antioxidant compounds during the drying process. This study aimed to scrutinize the effects of coating type and drying temperature on the quality of lemongrass and Malang apple powdered drinks. The study employed a completely randomized design (CRD) with two factors and two replications. The first factor was the coating type with 3 levels (maltodextrin, dextrin, gum arabic) and the second factor was the drying temperature with 3 levels (40℃, 45℃, 50℃). The data were analyzed using Analysis of variance one-way (ANOVA) test and Duncan's further test if the treatment was significantly different. The results showed that the type of coating significantly affected the parameters of stability, dissolution time, ash content, vitamin C, and antioxidants. Meanwhile, the drying time significantly affected the parameters of stability, dissolution time, water content, ash content, vitamin C, and antioxidants. There was an interaction between the coating type and drying time that affected the bulk density, stability, dissolution time, ash content, vitamin C, and antioxidants. The best result based on the high content of antioxidants was obtained on the dextrin coating type with a drying temperature of 45℃. Product characteristics included a solubility of 0.96 seconds, a bulk density of 0.58 g/mL, a stability of 89.19%, a water content of 2.38%, an ash content of 1.21%, a vitamin C content of 70.22%, an antioxidant inhibition percentage of 50.97%, an IC50 content of 1.29, and a water activity of 0.50.

Physiological Adaptations of Vegetables to Climate Stress

Vegetables, being rich in vitamins, carbohydrates, minerals, proteins and antioxidants are essential for overcoming micronutrient deficiencies, offering higher incomes and more employment opportunities per hectare to smallholder farmers compared to staple crops. Major challenges faced by vegetable growers are increased terminal heat stress, rainfall variability leading to flooding, drought, irrigation water availability, salinity, incidence of pests and diseases, extreme weather events. These gets further worsened in the future due to climate change. Vegetables exhibit various physiological adaptations to cope with changing environmental conditions such as enhanced photosynthetic efficiency, improved water-use efficiency, and altered phenological development. Higher temperatures accelerate the life cycle of vegetables cause increased respiration, leading to earlier maturation and potentially lower yields. Increased frequency of heat waves can cause heat stress, affecting growth and development. Moreover elevated temperatures increase the incidence of pests and diseases, leading to higher crop losses. Changes in precipitation patterns alter water availability, impacting growth and productivity. Nevertheless drought conditions cause stomatal closure limiting water loss besides reducing CO2 uptake. Excessive rainfall can lead to waterlogging, disrupting root function and nutrient uptake. Variability in climate conditions lead to inconsistent yields, making it challenging for farmers and necessitating adaptive strategies to ensure crop resilience and productivity. Genetic improvement through breeding for heat and drought tolerance helps to develop resilient vegetables. Additionally, agronomic practices like mulching, organic farming, and resource conservation technologies help mitigate the adverse effects of climate change. Understanding these physiological responses could streamline sustainable vegetable production in the face of a changing climate.

Determinants of plant species richness along elevational gradients: insights with climate, energy and water–energy dynamics

BackgroundUnderstanding the patterns and processes of species distributions has long remained a central focus of biogeographical and ecological research. While the evidence for elevational patterns in species richness is widespread, our understanding of underlying causes and mechanisms remains limited. Therefore, this study aimed to entangle the influence of environmental variables on plant species richness along elevational gradients in the Western Himalayas.MethodsWe compiled elevational distribution for about 1150 vascular plants using the published literature and available database. The species richness was estimated in 100-m elevational bands using the range interpolation method. We used the generalised linear model and structural equation modelling (SEM) framework to identify the direct and indirect effects of climatic factors on species richness.ResultsOur results indicated that primary environmental correlates of species richness varied with elevational gradients. Climatic variables combined with energy and water availability were more important than the topographic heterogeneity. Further, the direct and interaction effects of climatic variables were more substantial than their indirect effects. The indirect effects of climate are more strongly mediated by water–energy dynamics than the energy alone.ConclusionsOverall, our findings emphasise the importance of considering direct effects and interactions among environmental variables while studying the underlying mechanisms governing elevational biodiversity gradients. Species richness appeared to be shaped by climatic tolerances rather than habitat heterogeneity at regional scales. This information can have implications for biodiversity dynamics under environmental change.

Spontaneous nanosized liposome formation from crude dried lecithin upon addition of glycerol

Nanosized liposomal vesicles (NLV) were successfully prepared using natural sunflower lecithin without the use of high-pressure homogenization or filtration. Upon glycerol addition to dispersions of lecithin multilamellar vesicles (MLVs), these broke down spontaneously to liposomes with diameters in the range of 100–200 nm. Static light scattering demonstrated that glycerol addition above 30% (w/w) induced the complete transformation of MLVs into NLVs. Langmuir trough compression experiments showed a two-region compressional behavior. Upon 62% (w/w) glycerol addition, the compressional modulus of the liposomes decreased from 18.5 to 8.13 mN/m. Water activity and pulse NMR measurements also showed a divergence in behavior above 30% (w/w) glycerol. Liposomes were not birefringent in water but became strongly birefringent at and above 30% (w/w) glycerol, as determined by polarized light microscopy, and lost all birefringence above 80% (w/w). This was interpreted as the induction of stress-birefringence in the phospholipid bilayers above 30% (w/w) glycerol, and a relaxation of such stress above 80% (w/w) glycerol. We hypothesize that the mixture of phospholipids in the lecithin results in an effective non-zero intrinsic curvature for the molecular mixture, which lowers the bending energy of the bilayer, allowing for an easier break-up upon mixing. Secondly, glycerol addition decreases attractive van der Waals’ interaction between lamellae in an MLV, thus weakening the multilamellar liposome walls. Glycerol also affects bilayer stability by strengthening the hydrogen bond network of water, which will affect phospholipid headgroup hydration. All these factors result in the spontaneous breakdown of MLVs into NLVs.

Key role played by mesophyll conductance in limiting carbon assimilation and transpiration of potato under soil water stress

IntroductionThe identification of the physiological processes limiting carbon assimilation under water stress is crucial for improving model predictions and selecting drought-tolerant varieties. However, the influence of soil water availability on photosynthesis-limiting processes is still not fully understood. This study aimed to investigate the origins of photosynthesis limitations on potato (Solanum tuberosum) during a field drought experiment.MethodsGas exchange and chlorophyll fluorescence measurements were performed at the leaf level to determine the response of photosynthesis-limiting factors to the decrease in the relative extractable water (REW) in the soil.ResultsDrought induced a two-stage response with first a restriction of CO2 diffusion to chloroplasts induced by stomatal closure and a decrease in mesophyll conductance, followed by a decrease in photosynthetic capacities under severe soil water restrictions. Limitation analysis equations were revisited and showed that mesophyll conductance was the most important constraint on carbon and water exchanges regardless of soil water conditions.DiscussionWe provide a calibration of the response of stomatal and non-stomatal factors to REW to improve the representation of drought effects in models. These results emphasize the need to revisit the partitioning methods to unravel the physiological controls on photosynthesis and stomatal conductance under water stress.

Effects of drought on optimum temperature of carbon fluxes in temperate grasslands

Abstract Ecosystem carbon flux components, including ecosystem gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem productivity (NEP), are the most direct indicators of ecosystem production capacity, carbon sequestration, and climate regulation strength. Nevertheless, little is known about how water availability affects the temperature responses of carbon flux components in water-limited ecosystems. Based on a long-term eddy observation dataset of temperate grasslands in northern China, we analyzed the effects of drought on the optimum temperature of carbon flux components ( T opt flux ) in temperate grassland ecosystems and clarified the relative contributions of vegetation and climate factors to T opt flux . We found that the optimum temperatures of carbon flux components were widespread across different grassland types, with a significant lower optimum temperature of NEP ( T opt NEP , 17.32 ± 3.21 °C) than that of GPP ( T opt GPP , 18.67 ± 2.53 °C) and ER ( T opt ER , 19.30 ± 1.94 °C). Drought significantly reduced T opt NEP , but had no significant effects on T opt GPP and T opt ER . Obvious shifts of occurrence date of T opt flux were also observed in the years with different precipitation regimes. That is, T opt GPP and T opt NEP occurred significantly earlier than seasonal maximum temperature ( T max ) in the dry years, while T opt flux significantly lagged behind the occurrence of T max in the wet years. Water availability and vegetation factors co-regulated the spatiotemporal variations of T opt flux . In the dry years, precipitation and soil water content predominated the changes in T opt GPP and T opt ER , whereas vegetation structure (leaf area index) and physiological characteristics played a more important role in the wet years. Our study not only provided the first evidence for the widespread existence of T opt flux of different carbon fluxes, but also addressed the remarkable impacts of drought on T opt flux and their occurrence date in the water-limited grasslands. Therefore, incorporating the unimodality of these observed temperature responses of ecosystem carbon fluxes into land carbon models is necessary for improving the accuracy of carbon sequestration predictions.

Microencapsulation of Hibiscus sabdariffa extract in taro starch: Determination of optimal conditions of bioactive compound retention using response surface methodology

Hibiscus sabdariffa (HS) extract contains a large amount of bioactive compounds with antioxidant, anticarcinogenic, and antihypertensive effects. The extraction of total phenols, flavonoids, and anthocyanins is more efficient at boiling temperature (~91 °C) than that performed at room temperature (~27 °C). In this study, a central composite rotatable design (CCRD) was used to optimize the inlet temperature conditions of a spray dryer and the concentration of taro starch solids to obtain microcapsules with the highest retention of bioactive compounds in hibiscus extracts. Optimized microcapsules (OM) were obtained at an inlet temperature of 118 °C and solid concentration of 26.5 %. Low moisture content (4.54 %) and water activity (0.2) and high content of total phenols (3374.91 mg GAE/100 g), flavonoids (372.81 mg QE/100 g), monomeric anthocyanins (36.74 mg C-3-GE/100 g), and angiotensin-converting enzyme inhibitory activity (80.01 %), were determined in OM using response surface methodology. OM showed a range of spherical agglomerate sizes (10––32 μm). These results indicate that CCRD is a good tool for establishing the optimal conditions for solid concentration and drying temperature to maximize the protection of bioactive compounds using taro starch as the wall material.

Moisture uptake during storage of coffee packed into compostable capsules decreases the quality of coffee brew

Compostable bioplastics for coffee capsule production should satisfy compostability requirements while providing a moisture barrier able to guarantee the espresso coffee quality. The present study aimed at exploring the time required for coffee packed in biobased PBS capsules and stored under different temperature and relative humidity to reach critical moisture levels triggering quality decay. Samples were stored in plastic boxes containing supersaturated solutions of Mg(NO3)2, NaNO2 or NaCl guaranteeing 54, 65 or 75 % RH, placed at 20, 30 and 45 °C in thermostatic incubators. During storage, the coffee powder was analysed for moisture uptake and water activity, and the coffee brew was extracted to measure the pH, selected as the quality indicator. Over 18 months, moisture uptake rapidly increased, reaching critical levels within 3 weeks in the worst-case scenario (i.e., 45 °C and 75 % RH). The evolution of pH presented an initial lag phase and a subsequent linear decay, which were respectively shorter (< 15 days) and faster (pH < 5.1 within 1 month) in the worst-case scenario. The findings highlight the role of T and RH in affecting coffee quality decay and emphasize the potential drawbacks of adopting biopolymer-based packaging. These outcomes could help food manufacturers in scouting new packaging materials for coffee capsule applications, evidencing the potential drawbacks of replacing conventional packaging materials with biobased ones. In this regard, it is recommended that a thorough cost-benefit analysis is carried out before transitioning from conventional to compostable packaging to ensure sustainability goals are effectively met while maintaining product quality.

European anchovy's abundance, more affected by climatic conditions than fishing activities in the northwest African waters.

The marine waters off the coast of northwest Africa are known for being highly productive upwelling regions in the Eastern Atlantic Ocean. The present study evaluated the combined effects of climate change and sustainable fishing levels on the long-term sustainability of European anchovy (Engraulis encrasicolus), a target pelagic species found along the West African coastal waters. The present study used survey biomass time series from survey vessels and species catch time series from commercial fisheries operating in the region. Hence, we investigated the relationship between fishing dynamics and environmental factors. The status of anchovy stock was determined by analyzing changes in different initial depletion rates using a state-space Bayesian surplus production model. We used Principal component analysis to identify the essential environmental data set, while Generalized Additive Models (GAM) were employed to determine the influence of the environment on fisheries. The stock assessment model revealed that fishing intensity did not affect the abundance of anchovy in the region even when tested under different biomass depletion scenarios. However, by employing GAMs, the research assessed the impact of environmental variables on fish biomass, indicating that sea surface temperature (SST) significantly influences anchovy abundance in the region. The latitudinal gradient also had a significant influence on this species' abundance. These findings underscore the vulnerability of the small-scale fisheries sector in the tropical upwelling zone to climate change. The study concludes that even in the face of potential negative impacts from environmental factors, optimizing fishing methods can contribute to the preservation of pelagic resources in the region. It emphasizes the importance of managing fishery resources in a sustainable, economically viable, and socially acceptable way.

Advancing solar wastewater treatment: A photocatalytic process via green ZnO/g-C3N4 coatings and concentrated sunlight – Comprehensive insights into ciprofloxacin antibiotic inactivation

In this study, a sustainable method employing concentrated sunlight to achieve environmental remediation of wastewater, contaminated by Ciprofloxacin antibiotic (CIP), is thoroughly investigated. A green ZnO/g-C3N4 nanocomposite (NC) is used as a photocatalyst coating on glass to investigate the inactivation of CIP in water, in a flow-reactor configuration at small-prototype scale (10 liters/h, catalyst area 187.5 cm2). ZnO/g-C3N4 NC coatings were obtained by an in-situ thermal condensation process coupled with a green synthesis protocol and deposited on glass, via a simple drop casting method. Morphological and structural analyses of synthesized composites were performed with Fourier-Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques, while optical properties were studied with Diffuse Reflectance Spectroscopy (DRS). The degradation of CIP was first tested at a lab scale under simulated sunlight and then studied under sunlight in a parabolic trough concentrator (PTC). Suitable degradation of CIP (100%) was observed at 210 min via High-Performance Liquid Chromatography (HPLC) and the by-products were determined by Liquid Chromatography-Mass Spectroscopy (LC–MS). Microbiological tests revealed the absence of antibacterial activity in CIP water treated with ZnO/g-C3N4 NC photocatalyst against Staphylococcus aureus, Pseudomonas aeruginosa, and Priestia megaterium. Our results directly demonstrate the effective inactivation of CIP with a process designed for sustainability both in terms of energy input (solar) and scalability of materials. Also, the small-prototype scale of this investigation provides insights into the challenges arising from the perspective scale-up to an industrial application, aimed at antibiotics inactivation in wastewater and thus helping to prevent the spread of antimicrobial resistance (AMR).

New imidazole sensors synthesized for copper (II) detection in aqueous solutions

Water security, safety, availability and sustainability of water supply are increasingly problematic and difficult across the planet. Safe and rapid methods have been developed to purify water from cationic pollutants. New imidazole-derived fluorescent sensors, 2-(4,5-diphenyl-1-(p-tolyl)-1H-imidazol-2-yl) phenol (TS) and 2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl) phenol (AS), have been synthesized and characterized, and their possibility as fluorescence sensors for copper (II) has been examined. In CH3CN/H2O (90 v/v), the TS and AS revealed a noticeable an electronic band at 320.00 nm and fluorescence band at 460.90 nm. The ratio metric alterations in the absorption and fluorescence spectra of TS and AS due to the dative covalent bond between them and the copper (II) were shown by the findings of copper (II) titration. The sensing mechanism was validated by optical investigations and FT-IR spectra. In mixed solvent solutions, the selectivity of TS and AS to copper (II) as fluorescent sensors has been demonstrated, with sensitivity as low as 0.09 and 0.28 µM, significantly less than the limit permitted via the US EPA for drinking water (2.00 µM). The identification limits of TS and AS were assessed to be 0.05 and 0.50 µM, respectively, using the spectrophotometric procedure. Stoichiometry binding between TS and AS with copper (II) was found to be 2:1 (tetrahedral structure) as indicated by Job's method.

Molecular structures, solubility and pharmaceutical reactivities of flurbiprofen-based co-crystals: A DFT study

Pharmaceutical co-crystal has attracted increasing attention from researchers due to its potential to regulate the physicochemical properties of active pharmaceutical ingredient (API). Herein, three pharmaceutical co-crystals containing the API- flurbiprofen (FBP) and co-crystal formers (CCFs)- benzamide (BZA), picolinamide (Pic), salicylamide (SA) were constructed theoretically. The density functional theory (DFT) method was used to systematically investigate the structural parameters and chemical activities of these three co-crystals. The electrostatic potentials, Infrared and Raman spectra, binding energies, solvent energies, frontier molecular orbital energies, Hirshfeld surface analysis and global reactivity descriptors were investigated for both monomers and co-crystal systems. Moreover, the intermolecular interactions between the API and CCFs and Molecular Docking were also studied. Results show that the API combines with the CCFs together via the intermolecular hydrogen bond interactions. After co-crystallization with three CCFs, the water solubility and activity of FBP are enhanced, among which FBP-Pic shows the most excellent properties. Interestingly, FBP is more prone to form interaction with Butyrylcholinesterase (BChE) protein after forming co-crystal with Pic. This work could provide valuable reference and guidance for further research and application of pharmaceutical co-crystal in flurbiprofen.

A machine learning framework to measure Water Drop Penetration Time (WDPT) for soil water repellency analysis

The heat from wildfires volatilizes soil’s organic compounds which form a waxy layer when condensed on cooler soil particles causing soil to repel water. Timely assessment of soil water repellency (SWR) is critical for prediction and prevention of detrimental impacts of hydrophobic soils such as soil erosion, reduced availability of water to plants, and water runoff after rainfalls leading to floods. The Water Drop Penetration Time (WDPT), i.e., the time elapsed from a drop landing on the soil surface to its complete absorption is commonly used to assess the SWR level. Its manual measurements have variability based on the used instruments and subjective observations. The goal of this work is to design an automated system to perform standardized WDPT tests and assess the SWR levels. It consists of an electronically controlled mechanism to release a water drop, and a video camera to record the water penetration process. The latter is modeled as an “action” in video and Temporal Action Localization (TAL) analytics is used for predicting the WDPT and assessing the SWR level.

Impact of an extreme drought event on clonal reproduction and the acclimation capacity of the succulent plant Sempervivum tectorum L.

Functional traits have been defined as those that affect organismal performance, that is growth and development, reproduction and survival, so they have been generally associated with acclimation and adaptation. Here, we aimed to study the impact of an extreme drought event on clonal reproduction and hormonal mechanisms underlying acclimation of houseleek (Sempervivum tectorum L.), a plant adapted to survive harsh environments. We also explored the validity of growth- and stress-related phytohormones as functional traits to evaluate stress acclimation responses in the field. We compared the response of plants, considering both mother rosettes and newly produced clones, to a very extreme summer drought event occurring in small cliffs in Les Guilleries mountains (NE Spain). We measured various stress makers in the field together with hormonal profiling through a metabolomic approach using liquid chromatography coupled to tandem mass spectrometry. Results showed that clonal propagation was arrested during the study period and revealed a 100-fold increase in abscisic acid content from spring to summer both in mothers and new clones, concomitantly with reductions in relative water content, which decreased by 20% only. The stress-related bioactive jasmonate, jasmonoyl-isoleucine increased simultaneously with abscisic acid, while growth-related hormones, including bioactive cytokinins (2-isopentenyl adenine and trans-zeatin) decreased from spring to summer, which was consistent with growth arrest. It is concluded that S. tectorum adjusts recruitment of new clones during periods of low water availability and withstands extreme drought events during the summer (preventing severe cell turgor loss at soil water contents below 2% and temperatures above 43 ºC) by successfully activating a complex hormonal response that underlies the great capacity of this species to survive extreme climatic events.