Rate Of Water Uptake Research Articles

Toward estimation of seasonal water dynamics of winter wheat from ground-based L-band radiometry: a concept study

Abstract. The vegetation optical depth (VOD) variable contains information on plant water content and biomass. It can be estimated alongside soil moisture from currently operating satellite radiometer missions, such as SMOS (ESA) and SMAP (NASA). The estimation of water fluxes, such as plant water uptake (PWU) and transpiration rate (TR), from these earth system parameters (VOD, soil moisture) requires assessing water potential gradients and flow resistances in the soil, the vegetation and the atmosphere. Yet water flux estimation remains an elusive challenge especially on a global scale. In this concept study, we conduct a field-scale experiment to test mechanistic models for the estimation of seasonal water fluxes (PWU and TR) of a winter wheat stand using measurements of soil moisture, VOD, and relative air humidity (RH) in a controlled environment. We utilize microwave L-band observations from a tower-based radiometer to estimate VOD of a wheat stand during the 2017 growing season at the Selhausen test site in Germany. From VOD, we first extract the gravimetric moisture of vegetation and then determine the relative water content (RWC) and vegetation water potential (VWP) of the wheat field. Although the relative water content could be directly estimated from VOD, our results indicate this may be challenging for the phenological phases, when rapid biomass and plant structure development take place within the wheat canopy. We estimate water uptake from the soil to the wheat plants from the difference between the soil and vegetation potentials divided by the flow resistance from soil into wheat plants. The TR from the wheat plants into the atmosphere was obtained from the difference between the vegetation and atmosphere water potentials divided by the flow resistances from plants to the atmosphere. For this, the required soil matric potential (SMP), the vapor pressure deficit (VPD), and the flow resistances were obtained from on-site observations of soil, plant, and atmosphere together with simple mechanistic models. This pathfinder study shows that the L-band microwave radiation contains valuable information on vegetation water status that enables the estimation of water dynamics (up to fluxes) from the soil via wheat plants into the atmosphere, when combined with additional information of soil and atmosphere water content. Still, assumptions have to be made when estimating the vegetation water potential from relative water content as well as the water flow resistances between soil, wheat plants, and atmosphere. Moreover, direct validation of water flux estimates for the assessment of their absolute accuracy could not be performed due to a lack of in situ PWU and TR measurements. Nonetheless, our estimates of water status, potentials, and fluxes show the expected temporal dynamics, known from the literature, and intercompare reasonably well in absolute terms with independent TR estimates of the NASA ECOSTRESS mission, which relies on a Priestly–Taylor type of retrieval model. Our findings support that passive microwave remote-sensing techniques qualify for the estimation of vegetation water dynamics next to traditionally measured stand-scale or plot-scale techniques. They might shed light on future capabilities of monitoring water dynamics in the soil–plant–atmosphere system including wide-area, remote-sensing-based earth observation data.

Evaluation of cephalexin-loaded PHBV nanofibers for MRSA-infected diabetic foot ulcers treatment

The delayed and compromised diabetic foot ulcers (DFUs) healing due to methicillin resistance staphylococcus aureus (MRSA) is an emerging threat to human health and life. Developing new strategies to clear bacteria from ulcerative regions can be helpful to treat DFUs. The current study was designed to fabricate poly (3-hydroxy butyric acid-co-3-hydroxy valeric acid, (PHBV)), nanofibers (PHBV NFs) loaded with cephalexin (CPL) by electrospining technique to improve the bioavailability of CPL at the wound site to inhibit the bacterial growth and trigger the ulcer healing process. Morphological analysis shown that the electrospun nanofibers exhibited smooth surface morphology with an average diameter ranges from 205 ± 25 to 450 ± 55 nm, depending on the cephalexin concentration. The prepared nanofibers showed an enhanced drug loading capacity (LC) and entrapment efficiency (EE) of about 12.1 ± 1.6% and 75.3 ± 2%, respectively. The successful drug loading was also confirmed by FTIR analysis. Moreover, the CPL-loaded PHBV NFs exhibited high water uptake and biodegradation rate compared to blank PHBV NFs. The drug-loaded NFs initially showed a burst drug release followed by a sustained drug release profile with a constant rate up to 48 h. In-vitro studies show that CPL-loaded PHBV NFs exhibited an enhanced antibacterial activity against MRSA strains and have no visible toxic effect against keratinocytes, L929 and HEK293T cell lines. Further, CPL-loaded PHBV NFs showed the enhanced in-vivo bacterial clearance from DFUs using NcZ10 diabetic mice model compared to free CPL. Collectively, our results demonstrated that CPL-loaded PHBV NFs can be applied as a favorable dressing material to treat MRSA-infected chronic DFUs.

Improvement of the Degradation of Tensile and Impact Strength of Water-aged Sisal Fiber-reinforced Polyester Composites: A Comparative Study on the Effects of Hybridizations, Hybrid Layering Sequences, and Chemical Treatments

ABSTRACT This research aims to reduce the degradation of sisal fiber-reinforced polyester composites due to water absorption through chemical treatments and hybridizations. Sisal fibers were treated using sodium hydroxide (NaOH) and baking soda (NaHCO3). Unidirectional glass and carbon fibers were chosen as hybrid fibers. Thirteen laminates of pure sisal fibers, hybridized with glass or carbon fibers at different stacking sequences and volume fractions, were prepared using the hand layup technique. The laminates were examined for tensile and impact strength at dry and wet conditions. The effects of baking soda and sodium hydroxide treatments, glass and carbon fibers hybridization, and the sequence and volume of the hybrid fibers on the tensile strength, impact strength, water absorption, and degradation of the laminates were studied and compared. Chemical treatments and hybridizations have enhanced the tensile and impact strength of the composites. Significant reduction in the water uptake rate and degradation of the laminates were observed. Almost 166% and 87%, respectively, improvements were obtained in the tensile and impact strength of the dry samples. Moreover, more than 74% reduction in water uptake, and 84.7% and 91.7%, respectively, improvements in the degradation of the tensile and impact strengths were discovered.

Foliar water uptake in the needles of Pinus torreyana

The natural habitat of Pinus torreyana, the Torrey pine, is restricted to two locales in coastal Southern California that experience substantial fog and low clouds during the dry months of a Mediterranean climate. In similar semi-arid climate systems that encounter fog or low clouds, many plants can capture atmospheric moisture and are capable of direct foliar water uptake to reduce water stress. In this study, we investigated if the needles of P. torreyana are also capable of direct water uptake. In addition to water immersion, we measured the surface properties along a needle using microdroplets. The droplet contact angle is a measure of surface wettability, and the droplet absorption is a measure of localized foliar water uptake. The results showed that the entire length of the P. torreyana needle, including under the base sheath, is hydrophilic and capable of direct water uptake. The spatial gradients of the wettability and the water uptake along the needle are relatively small. Moreover, the wettability and water uptake increase from young shoots to one-year and two-year old needles. Our results also showed that the decrease in water uptake at higher contact angles can be described by a linear regression. Compared with the leaves of four shrubs in the same habitat, Heteromeles arbutifolia, Malosma laurina, Rhus integrifolia, and Eriodictyon crassifolium, the P. torreyana needles have lower contact angles and higher water uptake rates.

Carbon nanotubes decorated hollow metal–organic frameworks for efficient solar-driven atmospheric water harvesting

• Hollow MIL-101(Cr) is formed by etching for fast water capture and release. • Carbon nanotubes decorated hollow MIL-101 promotes photothermal performance. • The hierarchical porous structure enhances the water affinity under low humidity. • The water uptake and release rates are the highest among those reported. High equilibrium uptake capacity and rapid adsorption/desorption kinetics are essential to achieve efficient atmospheric water harvesting. In this work, carbon nanotubes decorated hollow MIL-101(Cr) particles (HMC-2) are prepared and utilized for solar-driven atmospheric water harvesting with nice water adsorption capacity and fast kinetics. The hierarchical porous hollow MIL-101(Cr) particles formed by post-etching show highly active defect sites and low mass transfer resistance, which promotes the adsorption and diffusion of water molecules. The resulted HMC-2 demonstrates a maximum water uptake of 1.074 g/g at 25 °C, 90% RH. Notably, the water adsorption capacity of HMC-2 in low humidity (40% RH) are increased by 113% and 202.6% compared to pure MIL-101(Cr) and carbon nanotubes decorated MIL-101(Cr). Due to the synergistic effect of CNTs and hollow MIL-101(Cr), the HMC-2 composites generate sufficient solar thermal heat and improve the desorption kinetics. The maximum adsorbed water of HMC-2 can be completely desorbed within 90 min under one sunlight. A single cycle of sorption–desorption of HMC-2 can be achieved within 210 min. This means that if the water harvesting cycle is performed three times daily, it is possible to harvest 3.22 L of water per kilogram of adsorbent at the area with high humidity. The water uptake and release rates of HMC-2 are competitive with even superior to most those reported. This may demonstrate a promising potential for atmospheric water generators.

Water uptake-induced pressure development by French bituminized radioactive waste products under nearly constant volume conditions

Water uptake and salt leaching of two simulated French Bituminized Waste Products (BWP) have been investigated under nearly constant volume conditions. The resulting pressure development was monitored during 5 to 6 years for two simulated BWP samples, varying one from the other by their inorganic load and composition. Pressure development induced by water uptake is mainly the result of two processes: (1) an osmotic phenomenon due to the presence of soluble and hygroscopic salts (NaNO3 and Na2SO4) embedded in the bitumen matrix and (2) recrystallization of anhydrous Na2SO4 into its decahydrate form, leading to an important volumetric expansion. After a certain hydration period, the pressure exerted by the hydrating BWP stabilizes when the pressure generating phenomena are fully counteracted by the leaching of soluble salts via out-diffusion, reconsolidation of pores in highly leached parts of the BWP, and/or some creep of the BWP into the technical voids of the water uptake cells. For one of the French BWP, this already occurred after 1 year of hydration. Differences are found in the pressure evolution and increase rate of the two studied BWP, though a much larger difference is observed when comparing the results of the French BWP to a Belgian BWP, i.e. Eurobitum. The faster pressure development observed for the French BWPs can be attributed to the differences in the soluble salt content, the inorganic load, the content of recrystallizing salts, but also to the presence of insoluble salts such as BaSO4, which seems to facilitate the water uptake rate in the French BWP. The faster hydration in French BWP results in a larger fraction of salts becoming available for osmosis and recrystallization within a relatively short time frame, thereby explaining the faster pressure build-up. On the other hand, BaSO4 does not seem to affect the leaching of soluble salts from BWP directly.

Calibration of Thermal Dissipation Probes for Date Palm (Phoenix dactylifera L.)

The quantification of water flow through the stem is vital for date palm (Phoenix dactylifera L.) to promote a good water stress management. The thermal dissipation probe (TDP) method developed by Granier is widely used to evaluate transpiration of forest trees; however, there are contradictory reports regarding its reliability. Considerable errors in estimated sap flux density, which might be due to a lack ofspecies-specific calibrations. The TDP method uses a mathematical model that is based on an empirical equation to estimate sap flux density, which is claimed to be applicable to all tree species, independently of wood structure and anatomy. At the laboratory, we compared the rate of water uptake by cut stems with sap flux estimates derived from the TDP method to assess the validity of the method.Our calibration results were considerably different compared to the Granier’s original equation. Moreover, sap flux density was overestimated by 18.2 ± 0.5% when the original calibration parameters of Granierare employed. However, using new calibration parameters improved the accuracy of sap flow measurements. Our results indicated that it is not appropriate to use a general equation for different species. Therefore, previous estimations of date palm’s water requirement through thermal dissipation probes should be revised.

Effect of seed coat microstructure and lipid composition on the hydration behavior and kinetics of two red bean (Phaseolus vulgaris L.) varieties.

Bean hydration is a crucial, yet complex process affected both by inherent bean properties (intrinsic) and properties of the soak medium (extrinsic) whose relationship with hydration kinetics are not clear. This work investigated the effect of temperature (30-80°C) on the hydration behavior and kinetics of two commonly consumed Phaseolus vulgaris L. beans-red kidney and small red beans. Both beans have similar morphology (except size), chemical composition and seed coat surface structure but, surprisingly, their hydration behaviors differed markedly. Small red hydration followed a sigmoidal shape (to 70°C) with a prominent lag phase at 30-40°C, while fast hydrating red kidney beans followed a downward concave shape, suggesting different mechanisms of water uptake. The hydration behaviors for red kidney and small red beans were modeled using Peleg (R2 ≥0.97) and sigmoidal (R2 ≥0.99) models, respectively. Water uptake rate increased, while equilibrium moisture content decreased for both bean varieties with increasing temperature. A simplified model was developed for small red beans which can predict hydration as a function of temperature and time with good accuracy ( , R2 =0.99, RMSE=4.5). Microscopic examination of cross sections of seed coats showed nearly double parenchyma layer thickness in small red bean and seed coat lipid analysis showed significantly higher proportion of saturated fatty acids which, together, may be responsible for slower water uptake observed in small red beans. PRACTICAL APPLICATION: Hydration is the crucial stage in dry bean processing, which precedes other processes like cooking, extraction, fermentation, sprouting, and consumption. Industrial bean processing is still slow and batch process and needs improvement. This work shows the effect of various bean properties and soaking medium temperature on the hydration behavior of two commonly consumed red beans. The work also modeled the hydration kinetics of two Phaseolus vulgaris L. beans which can be adopted by bean processors for process design and optimization.

Comparative assessment of egg and larval quality traits of progeny from wild-collected and captive-matured brooders of endangered golden mahseer, Tor putitora: A prelude to quality broodstock development and seed production

In this study, we assessed the differences in reproductive outputs (fertilization and hatching rates); egg quality (egg size increase during hardening, biochemical composition, carotenoid content, and characteristics of ovarian fluid); and larval performance traits (growth, microanatomical development, survival, starvation response, and critical thermal tolerance) of progeny from captive-matured and wild-collected golden mahseer brooders. Fertilization and hatching rates were significantly higher in wild-collected brooders than in captive broodstock. Captive brooder eggs were significantly larger in size and weight but had significantly lower energy/nutrient (total protein, glucose, and triglyceride) reserves and total carotenoids. On the contrary, ovarian fluid from captive females had significantly higher levels of total protein, glucose, and triglycerides, possibly indicating weaker egg membrane and nutrient leakage due to membrane damage or lysis. During water hardening, the cumulative weight increase due to a higher water uptake rate was significantly higher in the wild origin eggs than captive brooder eggs. CTmax of larvae obtained from captive-matured brooders was lower during the early developmental stages (15 dph), but became similar to the CTmax of wild brooder's larvae at 35 dph. On the other hand, CTmin of captive origin larvae was higher than their wild counterparts at all examined stages. There were no differences in starvation tolerance of larvae between the two brooder types. Histological observations revealed that the intestinal nutrient absorption and hepatic nutrient accumulating efficiency during the early developmental stages was relatively lower in captive origin larvae, corresponding to the comparative growth metrics observed until 35 dph. Also, the survival percentage at 90 dph was lower in the larvae of captive brooders than their wild counterparts. Collectively, these findings indicate potential areas for improvement in the captive broodstock management of the endangered cyprinid, golden mahseer.

Influence of co‐neutralization by sodium and zinc on the ethylene ionomer structure and properties

AbstractThis study investigates the properties and structure of poly(ethylene‐co‐methacrylic acid) (EMAA) ionomers co‐neutralized by zinc and sodium, and compares them with ionomers neutralized by a single metal: zinc (EMAA‐Zn) and sodium (EMAA‐Na). The bending stiffness and the degree of crystallization for the co‐neutralized ionomer (Na:Zn = ~1:1 on a molar basis) gives 16.5% and 9.8% increase compared to the simple average of their single cation counterparts. Such unusual properties are seen in mechanical, thermal, and rheological properties and water uptake rate in this study. Infrared spectra of the co‐neutralized ionomer shows changes at the carboxylate antisymmetric stretching band, which correspond to the formation of carboxylates bridging zinc and sodium ions. X‐ray scattering identified that the number density of ionic multiplets for the co‐neutralized ionomers are equivalent to EMAA‐Na and ~ 1.7 times higher than EMAA‐Zn. The fraction of side groups forming ionic multiplets, β, in co‐neutralized ionomers were 0.7–0.8, close to EMAA‐Na (1.0) and higher than EMAA‐Zn (0.3), indicating that sodium promote zinc to form ionic multiplets. The synergistic properties induced by co‐neutralization are ascribed not only to a formation of new ionic multiplets where both cations are included but also to the change in the number density of ionic multiplets.

Development of a novel reinforced scaffold based on chitosan/cellulose nanocrystals/halloysite nanotubes for curcumin delivery

Chitosan, cellulose nanocrystals, and halloysite nanotubes in the presence of calcium cations were used to fabricate a three-dimensional nanocomposite scaffold. The FTIR and XRD analyses revealed that formation of the network and incorporation of halloysite nanotubes into it were successful. FESEM images showed that the addition of higher amounts of halloysite nanotubes into the scaffold's matrix leads to more and smaller pores. The addition of halloysite nanotubes enhanced the thermal stability, mechanical characteristics, water uptake, and degradation rate of the nanocomposite scaffold. The nanocomposite scaffold represented good biomineralization, great cell proliferation, and acceptable cell attachment. Furthermore, the capability of the nanocomposite scaffold for curcumin delivery was approved through cell proliferation, cumulative release, and antibacterial studies. Cell proliferation of the nanocomposite with 10 wt% curcumin-loaded halloysite nanotubes reached around 175% after 72 h. Considering the results, the prepared nanocomposite scaffold holds great potential for being used in bone tissue engineering applications.

Water uptake kinetics in soaking of grass pea

Grass pea (Lathyrus sativus) is a pulse of great importance for food and feed due its high resistance to poor environmental conditions. However, it contains anti-nutritional factors and a neurotoxin, which is partially lost during soaking. A first approach to mass transfer during the soaking of grass pea was carried out by modeling the water uptake during soaking time using empirical mathematical models. The water uptake behavior was successfully described by the Peleg and the Exponential models, with these models showing several advantages when compared to the Mitscherlich and Page models. Both models estimated an increase of the equilibrium moisture content at temperatures between 50 °C and 100 °C, and detected an increasing effect of the area per volume ratio of the seed on the water uptake rate, but only at 75 °C and 100 °C. Additionally, grass pea presented a high true porosity, 13.651%, showing that it contains a large empty volume into which water can enter by capillary flow. Solids loss was observed to be high, varying from 18% at 25 °C to 44% at 100 °C for long soaking times, confirming that its effect in soaking cannot be neglected.

Reactive transport modelling the oxalate-carbonate pathway of the Iroko tree; Investigation of calcium and carbon sinks and sources

The oxalate carbonate pathway (OCP) of the Iroko tree has been shown to function as a carbon sink, due to the precipitation of calcium (Ca) carbonate in the tree and the soil around its roots, a soil developed on a carbonate-free bedrock. A 1D reactive transport (RT) model of the Iroko OCP system was constructed and used in a sensitivity analysis to replicate the geochemical pathway of the OCP and carbon sequestration, constrained by the Ca mass balance. The sensitivity analysis examined ranges of contributions for Ca sources to the system, including rainfall, dust, plant decomposition, mineral weathering, and optionally groundwater Ca sources. The study focused on identifying possible scenarios by which the observed magnitude of accumulated soil calcite could be reproduced, related to the OCP geochemical pathway. In line with field observations of the Iroko, all model results showed a soil transition from acidic (pH 5.1) to mildly alkaline (maximum pH 8.1) conditions, as well as precipitation of calcite. The location of calcite precipitation remained within the upper reach of the soil column, and between 29% and 63% of carbon was retained as calcite. The magnitude of calcite precipitation was limited both by the availability of Ca from the various sources, and by the tree’s rate of root water and solute uptake. The sensitivity analysis confirms that surficial sources such as rainfall and dust deposition contribute only a small fraction of Ca, and indicate that mineral weathering and the extent of the root system, must play a dominant role in supplying Ca to facilitate carbon sequestration through calcium carbonate formation.

Water absorption mechanism and mechanical performance of adhesively joint aluminum alloy with GNP reinforced epoxy

This work investigates the effects of Graphene Nanoplatelets (GNP) reinforcement to water absorption behavior and mechanical properties of adhesively joint aluminum. 1.0 wt% GNP was incorporated into epoxy adhesive to joint aluminum adherend subjected to various immersion periods (10–60 days) for investigating its effect on water uptake, water absorption rate and shear strength. When compared to pristine adhesive, GNP reinforced epoxy exhibit two distinct trends with regard to water uptake and water absorption rate; i) at lower immersion period (10–40 days), increased water uptake and water absorption rate is observed where highest increment recorded are 99.9% and 98.2% respectively at 10 days immersion period, while ii) at longer immersion period (50–60 days) reduced water uptake and water absorption rate is observed where lowest value recorded are 18.4% and 17.9% respectively, at 60 days immersion period. When compared to pristine epoxy, regardless of immersion periods, GNP reinforced specimens have more or less demonstrated retention/deterred joining performance. In this work, it is noted that all fractured specimens with GNP reinforcement demonstrate the combination of both cohesive and adhesive fracture.

The influence of interfacial failure on the tensile S–N response of aged Arcan joints

AbstractThe strength and durability of adhesive joints are significantly influenced by environmental conditions. Humidity absorption can cause deleterious effects on the adhesive joint's performance. The current study investigates the tensile properties of an epoxy‐based adhesive using Arcan joints (which is a kind of butt joint) subjected to different aging levels and loading conditions. To this end, joints with different aging times, as well as reference‐dried samples, were subjected to both the static and cyclic loading conditions. To construct the S–N curves, different cyclic load levels were applied to the joints. The static results showed that the mechanical properties, such as tensile strength of the joints decreased with an increase of the aging time. The fatigue strength and the fatigue lifetime were significantly decreased by the increase of aging levels, mainly due to an interfacial aging phenomenon. The water diffusion in interfacial aging is faster than that of the adhesive aging, which resulted in a premature failure of the joints for both the static and fatigue conditions. Based on the experimental results, the interfacial diffusion coefficient was calculated using an inverse method. According to the results, the rate of water uptake along the interface is more than 30 times higher than that which occurs in the adhesive.

Tradeoffs and Synergies in Tropical Forest Root Traits and Dynamics for Nutrient and Water Acquisition: Field and Modeling Advances

Vegetation processes are fundamentally limited by nutrient and water availability, the uptake of which is mediated by plant roots in terrestrial ecosystems. While tropical forests play a central role in global water, carbon, and nutrient cycling, we know very little about tradeoffs and synergies in root traits that respond to resource scarcity. Tropical trees face a unique set of resource limitations, with rock-derived nutrients and moisture seasonality governing many ecosystem functions, and nutrient versus water availability often separated spatially and temporally. Root traits that characterize biomass, depth distributions, production and phenology, morphology, physiology, chemistry, and symbiotic relationships can be predictive of plants’ capacities to access and acquire nutrients and water, with links to aboveground processes like transpiration, wood productivity, and leaf phenology. In this review, we identify an emerging trend in the literature that tropical fine root biomass and production in surface soils are greatest in infertile or sufficiently moist soils. We also identify interesting paradoxes in tropical forest root responses to changing resources that merit further exploration. For example, specific root length, which typically increases under resource scarcity to expand the volume of soil explored, instead can increase with greater base cation availability, both across natural tropical forest gradients and in fertilization experiments. Also, nutrient additions, rather than reducing mycorrhizal colonization of fine roots as might be expected, increased colonization rates under scenarios of water scarcity in some forests. Efforts to include fine root traits and functions in vegetation models have grown more sophisticated over time, yet there is a disconnect between the emphasis in models characterizing nutrient and water uptake rates and carbon costs versus the emphasis in field experiments on measuring root biomass, production, and morphology in response to changes in resource availability. Closer integration of field and modeling efforts could connect mechanistic investigation of fine-root dynamics to ecosystem-scale understanding of nutrient and water cycling, allowing us to better predict tropical forest-climate feedbacks.

Putting Plant Roots at Light: Temporal Imaging of Plant Roots and Soil Water with a Light Transmission Technique for Linking Water and Root Observations to Soil-Plant Models.

Estimating how the "hidden half" of plants, that is the roots, take up water or the influences of root system architecture or root physiological properties (such as root hydraulic conductance) on efficiency of water uptake is of prime importance for improving crops against water deficits. To unravel soil-root interactions for water, we describe a system that enables a dynamic imaging of the soil water content and of the root system, from the single root to the whole root system scales.This system uses plants grown in rhizotrons filled with sandy soil and is based on the variable attenuation of the intensity of light transmitted through the rhizotron with soil water content (the rhizotron is nearly translucent when saturated and becomes darker as soil water content decreases). Images of the transmitted light during plant water uptake (or exudation) phases are recorded with a camera, showing a qualitative pattern of water content variations. The gray levels of the image pixels are then quantitatively related to water content with a calibration.This system is affordable and can be easily implemented without specific equipment. It is scalable and quick to allow the phenotyping of a range of plant genotypes relative to their water uptake pattern. This pattern can be then related with root system properties (soil colonization, root architecture ) at different plant stages. In combination with modeling , imaging results help in obtaining physiological parameters such as root hydraulic conductivity, distributed root water uptake rates or root xylem water potential. Combination of modeling and experiment further helps in testing biological and physiological assumptions and in predicting the uptake behavior of plants in the field.

Controlled-release granules for the delivery of pymetrozine to roots of transplanted rice seedlings with decreased phytotoxicity and enhanced control efficacy against paddy planthoppers.

Seedling transplanting is widely used in rice cultivation. Systemic insecticides can be delivered to seedling roots by application through rice seedling boxes before transplanting. The most challenging aspect is to provide long-term control of rice pests and overcome transplanting shock. Precise control of the release rate of insecticide can meet these requirements. Pymetrozine is a promising insecticide used for the control of rice planthoppers resistant to neonicotinoid insecticides. In this study, four controlled-release granular formulations of pymetrozine were prepared based on a mixture of cost-effective and biodegradable kaolin and xanthan gum or a mixture of calcined kaolin and xanthan gum. Fluorescence images showed that different 3D networks were formed in the four granular formulations. The four granular formulations showed different water uptake rates and release rates of pymetrozine in water. Pymetrozine release rate was positively correlated with the water uptake capacity, rather than the water uptake rate of granules. Diffusion was the dominant mechanism for the release of pymetrozine from granules. Pymetrozine was found to reduce the survival of transplanted rice seedlings suffering from transplanting shock. Incorporating pymetrozine in controlled-release granules alleviated this phytotoxicity. The survival rate of rice seedlings in granular pymetrozine treatments ranged 68.8-85.0%, whereas the survival rate was <50% for powdered pymetrozine treatments. Additionally, four prepared granule formulations had a significant control effect on rice planthopper with efficacies ranging from 76.7% to 98.0% 40 days after seedling box treatment. The granule with an intermediate release rate of pymetrozine was shown to be more suitable for seedling box treatment than field application and traditional liquid spraying for the long-term control of paddy planthoppers. © 2021 Society of Chemical Industry.

Extrusion‐based 3D printing of gelatin methacryloyl with nanocrystalline hydroxyapatite

AbstractThe particle shape and size distribution of inorganic fillers play a crucial role in the scaffold buildability when those are incorporated in the viscoelastic polymers. In order to address this issue, the phase pure rod‐shaped nanocrystalline hydroxyapatite (HAp) powders with varying particle sizes and shapes were synthesized by a one‐pot hydrothermal method without any regulatory surfactant at an initial solution pH of 9. As‐synthesized nanocrystalline HAp particles (0–5 wt%) were incorporated into 15 wt% pre‐cross‐linked gelatin methacryloyl (GelMA) hydrogel matrix to fabricate a predesigned scaffold architecture using a custom‐made 3D bioprinter. The printing parameters (nozzle diameter, extrusion pressure, and printing speed) were optimized for each composition. The biophysical properties (uniaxial compression behavior, swelling ratio, and in vitro degradation) of the composite hydrogel scaffolds were critically analyzed to unravel the role of nano‐sized HAp addition. The compression strength and modulus were substantially improved, while the rate of water uptake and bio‐enzymatic degradation significantly reduced with HAp content. We propose that the inorganic–organic nanocomposite hydrogel could be efficiently assembled to formulate a potential bioink for 3D bioprinting applications toward tissue regeneration.

Thermomechanical Characterization Of Organo-Clay Epoxy Nanocomposites for Use in Civil Infrastructure

ABSTRACT Epoxy nanocomposites based on organically treated clays been researched extensively for use in aerospace, automotive, and electronic packaging applications. The potential low cost, decreased diffusivity and moisture uptake, and increase in stiffness and toughness, as well as the ability of the nanoclay particles to serve as a flame retardants and decrease flammability make these materials of immense interest for civil infrastructure applications especially as related to addressing long-term durability. This work analyzes the cure, thermomechanical (DMTA), moisture uptake and tensile characteristics of montmorillonite-epoxy nanocomposites. It is shown that the organo-clays serve as a catalyst for the curing reaction and reduced the exothermal peak temperatures with an increase in activation energy of cure at higher degrees of conversion. The nanocomposites demonstrated enhanced stiffness, relatively minor drops in glass transition temperature, increased thermal stability, and substantially decreased water uptake and diffusion rates, emphasizing their potential for use in civil infrastructure applications wherein nonaerospace cure techniques are used.