High Percolation Research Articles

Impact of Post-Thaw Enrichment of Primary Human Hepatocytes on Steatosis, Inflammation, and Fibrosis in the TruVivo® System

Background: Liver diseases are a global health concern. Many in vitro liver models utilize cryopreserved primary human hepatocytes (PHHs), which commonly undergo post-thaw processing through colloidal silica gradients to remove debris and enrich for a viable PHH population. Post-thaw processing effects on healthy PHHs are partially understood, but the consequences of applying disease-origin PHHs to post-thaw density gradient separation have not been described. Methods: Using the TruVivo® system, diseased, type 2 diabetes mellitus (T2DM), and fibrotic PHHs were cultured for 14 days after initially being subjected to either low-density (permissive) or high-density (selective) gradients using Percoll-based thawing medium. Results: Changes in functionality, including albumin and urea secretion and CYP3A4 activity, were measured in diseased, T2DM, and fibrotic PHHs enriched in low Percoll compared to PHHs enriched in high Percoll. Lipogenesis increased in the PHHs enriched in low Percoll. Higher expression of CK18 and TGF-β, two fibrotic markers, and changes in expression of the macrophage markers CD68 and CD163 were also measured. Conclusions: The use of Percoll for the enrichment of PHHs post-thaw results in differences in attachment and functionality, along with changes in diseased phenotypes, in the TruVivo® system.

Digital light processing printed resin based conductive composites with CF@Ag and HGMs@Ag as fillers for metamaterial absorbers

AbstractAn integrated fabrication process based on multi‐material Digital Light Processing (DLP) technique for metamaterial absorbers (MMAs) is proposed. Considering the requirements of the DLP process for the rheological properties and photocuring properties of the slurry, a photopolymer resin slurry was developed using silver‐plated carbon fiber (CF@Ag) and silver‐plated hollow glass microspheres (HGMs@Ag) as conductive fillers. To meet the conductivity requirements of resistive films in MMAs, the study systematically investigated the influence of material parameters and DLP process parameters on the conductivity and precision of the fabricated patterns. Optimized DLP parameters for isotropic photocurable conductive composites with high conductivity and low percolation thresholds were obtained. Additionally, a MMAs was designed to achieve effective absorption in the wavelength range of 7 to 28 GHz. The absorber utilized a resistive film with a thickness of 30 μm and an average surface resistivity of 23 ohm/sq., prepared using a photocurable resin filled with a total mass fraction of 35 wt% CF@Ag and HGMs@Ag in a 2:1 mass ratio. This work shows that it is feasible to fabricate resistive film patterns with prescribed surface resistivity and geometric shapes through DLP printing directly without sintering, providing a promising process for the integrated manufacturing of high‐performance MMAs.Highlights Developed a conductive slurry using the synergy between CF@Ag and HGMs@Ag. Proposed the preparation process of resistance controllable resistive film. The first demonstration of manufacturing resistive film‐type MMAs via DLP.

Timescale of Groundwater Recharge in High Percolation Coastal Plain Soils

Understanding and modeling the timing and magnitude of groundwater recharge from rainfall infiltration through vadose-zone percolation is important for many reasons but especially because the flux is being acted on by root-zone evapotranspiration (ET), and very little rainfall infiltration ever becomes water-table recharge. This study elaborates on the considerable time of the wetting front’s arrival and ultimate bulk recharge of rainfall infiltration in the shallow water table with fine-sandy soil typical of coastal plain environments such as Florida. Calibrated Hydrus-1D modeling of Florida (Myakka) soil was evaluated at varying depths of the water table and hydraulic conductivities to bracket the timing of arrival of the wetting front and bulk fluxes. Useful normalized timing parameters are defined. In addition, this research further quantifies the concept of “wet equilibrium”, and the considerable vadose-zone storage potential over and above the hydrostatic pressure equilibrium that must be overcome to achieve any significant water-table recharge in typical seasonal hydrologic timescales. The results indicate recharge timescales for water-table depths of 1 m are approximately 1 day but are considerably longer for 2 m (2 weeks), 3 m (1 month), and 4 m (50 days) conditions. Given that daily vadose-zone potential ET demand can exceed 0.5 cm/day in this environment, estimating recharge from rainfall infiltration is likely unreliable unless this timescale and the plant-root-zone uptake processes are properly modeled in surface-groundwater models.

Flexible PVA/Co Ferrite/MWCNT/AC Metacomposites: High Conductivity and Low Percolation Threshold

Flexible PVA/Co Ferrite/MWCNT/AC Metacomposites: High Conductivity and Low Percolation Threshold

2D lattice animal formation in the irreversible aggregation of patchy particles

With the self-assembly of patchy colloids, we can engineer many complex structures. In the present work, we are modeling spherical particles with 2 diagonally opposite patches using the Kern-Frenkel potential coupled with isotropic square well potential having different interaction ranges. The isotropic square well potential formed reversible bonds while the patches were irreversibly bonded. A state diagram is calculated where we observed a range of structures from a 1D chain, 2D planar cluster, and 3D random clusters depending on the width of the patch. These structures are controlled by the number of bonds each patch can form for a given patch angle. The range of the patch width can be analytically calculated using geometric arguments to identify different types of clusters, which agree with our simulations. The aggregation process was diffusion-limited, forming clusters with fractal dimension 2 in the low volume fraction limit, otherwise known as flocculation region, and 2.5 in the high volume fraction limit or percolation region, irrespective of the type of clusters formed. In the flocculation limit of the DLCA aggregation model, we expect a fractal dimension of 1.8, contrary to that, we observed the formation of lattice animals having a fractal dimension of 2. The presence of lattice animals is confirmed using the scaling laws of size distribution and chemical length of the clusters formed in the flocculation limit.

Flexible piezo-resistive strain sensors using all-polydimethylsiloxane based hybrid nanocomposites for wearable electronics.

We report flexible piezo-resistive strain sensors composed of silver nanoparticle (Ag NP), graphene nanoplatelet (GNP), and multi walled carbon nanotube (MWCNT)-based ternary conductive hybrid nanocomposites as an active sensing layer fabricated using a simple solution processing method on flexible polydimethylsiloxane (PDMS) substrates. The electrical characteristics have been studied in PDMS-based flexible devices having three different kinds of structures, namely Ag NPs/MWCNT/PDMS, GNP/PDMS and Ag NPs/GNP/PDMS. The microscopic analysis of the hybrid nanocomposites is undertaken using field emission scanning electron microscopy. The diameter of the CNTs is found to be in the range of 20-40 nm, whereas the length is determined to be 100-800 nm. The average diameter and length of the GNPs are observed to be 30-50 nm and 100-500 nm, respectively. The crystallite size of the silver nanoparticles in the Ag NPs/MWCNT/PDMS and Ag NPs/GNP/PDMS-based nanocomposites is determined to be 22.8 nm and 29.1 nm, respectively. The prepared sample of Ag NPs shows four distinct peaks in the X-ray diffraction pattern, which correspond to the (111), (200), (220), and (311) face-centered cubic (FCC) crystalline planes. Raman spectroscopy is undertaken to study the fundamental physical properties and chemical analysis of the nanocomposites. Ag NPs/GNP/PDMS-based sensors exhibit superior performance in terms of sensitivity, response and recovery time during breathing/unbreathing analysis. The large surface area of the Ag NPs and GNPs promotes uniform distribution of Ag NPs to fill into the porous GNP surface, thereby facilitating high contact area along with better electron transport in the Ag NPs/GNP/PDMS hybrid nanocomposite-based sensors. The gauge factor (GF), response and recovery time of the Ag NPs/GNP/PDMS hybrid nanocomposite-based sensors are determined to be 221, 130 ms and 119 ms, respectively. The ternary conductive nanocomposite-based sensors are free from the drawbacks of binary nanocomposite-based sensors where the high percolation threshold and poor mechanical behaviour lead to the degradation of the device performance.

Subcritical Connectivity and Some Exact Tail Exponents in High Dimensional Percolation

Subcritical Connectivity and Some Exact Tail Exponents in High Dimensional Percolation

Improved piezoresistive sensing behavior of poly(vinylidene fluoride) / carbon black composites by blending with a second polymer

For the production of low-cost conductive polymer composites (CPCs), carbon black (CB) is a suitable conductive filler that provides higher piezoresistive sensitivity compared to highly anisotropic fillers such as carbon nanotubes. However, the use of CB containing CPCs as sensor materials is limited by high electrical percolation threshold (Φc) and poor signal linearity. In this work we demonstrate that the addition of either amorphous poly(methyl methacrylate) (PMMA, 20 wt%) or partially crystalline poly(butylene succinate) (PBS, 30 wt%) tunes the piezoresistive behavior of composites based on partially crystalline poly(vinylidene fluoride) (PVDF) and CB (3 and 4 wt%), due to a changed phase morphology and network arrangement. Significantly improved piezoresistive linearity compared to the corresponding composites with a pure PVDF matrix was achieved. Thereby, the sensitivity at small initial strains is not compromised. Furthermore, the addition of 30 wt% PBS reduced the electrical percolation threshold significantly, so that samples with the low amount of 1.5 wt% CB became available for piezoresistive testing. This blend composite shows a nearly linear piezoresistive behavior with a significantly enhanced relative electrical resistance change ΔR/R0 of 71.8 ± 7.1% at 5% strain. This value is much higher than those achieved in the PVDF-CNT (1–2 wt%) or PVDF-CB (3–4 wt%) composites (ΔR/R0 lower than 40%).

Improving morphology of P3HT:PCBM bulk heterojunction solar cells with anisotropic shaped silica nanoparticles

Using coarse-grained molecular dynamics simulations we study blends of Poly(3-hexylthiophene-2,5-diyl) (P3HT), [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) and Silica nanoparticle (SiNP) to understand the effect of adding SiNP on morphology of P3HT:PCBM in Bulk heterojunction (BHJ) solar cells. We use an approximately 3 nm anisotropic shaped SiNP and predicted the morphology of BHJ upon its incorporation. The SiNP arrange themselves into anisotropic structures depending on the concentration of P3HT, PCBM and SiNP respectively creating a network like morphology. PCBM molecules utilize the surface energy of SiNP and gather at its surface forming a morphology which is beneficial for device efficiency. Our results suggest that an optimum weight fraction of all the three components leads to higher surface area of contact, optimum domain size and high percolation of domains throughout the system. The effective control of all the morphological parameters help in improving the charge generation, extraction and transport to electrodes, thereby improving the performance of BHJ solar cells.

Hypogene speleogenesis related to porphyry magmatic intrusions and its influence on subsequent karst evolution in the Peruvian high Andes

Carbonate rocks of Cretaceous and Jurassic age are widespread in the Peruvian Andes where they host numerous magmatic intrusions and related ore deposits. Most of Peru's metal ore deposits are located at high elevations within a narrow, tectonized carbonate-rock belt extending over 2000 km in length. Many of the limestone formations are karstified and characterized by high recharge and percolation rates, well-developed subsurface drainage and complex flow patterns. Knowledge of karst in the Andes is generally limited, although karst is recognized to cause extreme hydrogeologic complexity and great challenges in development of mining facilities located in carbonate settings. Aspects of the origin of void/conduit systems (i.e. speleogenesis) and karst evolution are rarely addressed in environmental impact and risk assessment studies.This study in the Antamina area in the east side of the Cordillera Occidental, home to the world largest known skarn copper‑zinc deposit, demonstrates that the current karst system has formed as the result of polygenetic and multi-phase development. Structure-controlled hypogene cave systems are well-preserved and widespread in the area and present a foremost example of endogenous hypogene speleogenesis related to magmatic intrusions. Hypogene karst structures have strongly influenced subsequent epigene karstification, which commenced at the Pliocene-Pleistocene boundary. Changes in the base-level position due to the landscape evolution and Pleistocene glaciations were major additional factors that influenced epigene karst development. The findings of this study are potentially relevant to assessing karst origin and hydrogeology in many carbonate-hosted ore deposits in the Peruvian Andes and other regions. This study shows that the speleogenetic and evolutionary approach is indispensable in the development of sound conceptual models of groundwater flow in karst terrains and the assessment of karst-related hazards and risks.

Trend Analyses of Percolation of Atmospheric Precipitation Due to Climate Change: Case Study in Lithuania

The aim of this paper is to identify the trends of changes in atmospheric precipitation percolation under the changing climate conditions of Lithuania (the East Baltic region) based on long-term lysimeter studies. Data from 1987–2022 research (n = 1296) was used to determine trends in precipitation infiltration changes. Two 10-year periods, 1989–1998 and 2011–2020, were selected from the whole observation period (1987–2022) to assess changes in precipitation infiltration due to climate change. The air temperature has increased significantly in November (+3.4 °C) and December (+3.3 °C), with a +2.2 °C increase in the standard climate normal. The distribution of yearly precipitation has changed, with the annual amount decreasing from 686 to 652 mm. Precipitation increased the most in July and August (10.9 and 22.9 mm). In autumn, the amount of precipitation decreased by 7.9–31.1 mm. The number of rainy days did not change during the year, but the frequency of heavy precipitation increased significantly in August. The annual percolation increased by 14.2% over 2011–2020 compared to 1989–1998. Percolation increased by 19.0, 22.3, and 20.1% during the spring, autumn, and winter, respectively, and decreased by 35.0% in summer. The increase in annual percolation is mostly related to the increase in temperature during the cold season: November and December. During these months, the likelihood of early freeze formation, which interrupts gravitational water percolation in soil, is significantly reduced. In the spring, the increase in average air temperatures in March leads to faster melting of the winter snow in a shorter period, which significantly increases percolation processes. In Lithuania, higher percolation in autumn and winter, when part of the agricultural land is not covered by vegetation, may lead to higher leaching of chemical elements.

Assessing Spatio-Temporal Dynamics of Deep Percolation Using Crop Evapotranspiration Derived from Earth Observations through Google Earth Engine

Excess irrigation may result in deep percolation and nitrate transport to groundwater. Furthermore, under Mediterranean climate conditions, heavy winter rains often result in high deep percolation, requiring the separate identification of the two sources of deep percolated water. An integrated methodology was developed to estimate the spatio-temporal dynamics of deep percolation, with the actual crop evapotranspiration (ETc act) being derived from satellite images data and processed on the Google Earth Engine (GEE) platform. GEE allowed to extract time series of vegetation indices derived from Sentinel-2 enabling to define the actual crop coefficient (Kc act) curves based on the observed lengths of crop growth stages. The crop growth stage lengths were then used to feed the soil water balance model ISAREG, and the standard Kc values were derived from the literature; thus, allowing the estimation of irrigation water requirements and deep drainage for independent Homogeneous Units of Analysis (HUA) at the Irrigation Scheme. The HUA are defined according to crop, soil type, and irrigation system. The ISAREG model was previously validated for diverse crops at plot level showing a good accuracy using soil water measurements and farmers’ irrigation calendars. Results show that during the crop season, irrigation caused 11 ± 3% of the total deep percolation. When the hotspots associated with the irrigation events corresponded to soils with low suitability for irrigation, the cultivated crop had no influence. However, maize and spring vegetables stood out when the hotspots corresponded to soils with high suitability for irrigation. On average, during the off-season period, deep percolation averaged 54 ± 6% of the annual precipitation. The spatial aggregation into the Irrigation Scheme scale provided a method for earth-observation-based accounting of the irrigation water requirements, with interest for the water user’s association manager, and at the same time for the detection of water losses by deep percolation and of hotspots within the irrigation scheme.

What Nanomaterials Can Do for Energy Storage: Production of Charged, Individualised Nanomaterials (CINs) As Novel Materials for Electrochemical Energy Storage Devices

Electrochemical energy storage devices, such as batteries and supercapacitors, allow us to store electrical energy as chemical energy. They are a vital component of the UK’s plans to achieve net-zero carbon emissions by 2050.1 Nanomaterials offer properties such as short ion diffusion distances, high percolation to form conductive networks, and structural frameworks that can withstand mechanical stresses from successive volume expansion-contraction cycles on insertion-deinsertion of guest ions. Thanks to these properties, incorporation of nanomaterials into electrochemical energy storage devices could allow them to store more energy, last longer, and cope with the load cycles required for grid storage.2 However, the use of nanomaterials in commercial devices is limited by their low density and tendency to agglomerate. In addition, established synthesis methods such as high energy sonication and Hummer’s method yield nanomaterials with properties that fall short of those predicted theoretically, by resulting in a distribution of few-layer materials, and introducing defects that might not benefit electrochemical performance.This work uses highly reducing solutions, such as alkali metal-ammonia solutions or sodium naphthalide solutions, and subsequent spontaneous dissolution in polar aprotic solvents, to individualise nanomaterials and introduce negative charge to the surface in a single step (Figure 1).3,4 This produces exclusively monolayer, pristine, negatively-charged, individualised nanomaterials (CINs). This synthesis route can be applied to a wide range of materials, such as layered materials like graphite and transition metal dichalcogenides, as well as carbon nanotubes and other carbonaceous materials. The negative charge introduced can be used in subsequent synthesis steps to add functionality, grow nanoparticles, and control assembly into 3D structure. Using starting materials such as graphite, carbon nanotubes, and phosphorus,5 this work presents the application of these methods to investigate what new materials can be made. Furthermore, their electrochemical performance in batteries and supercapacitors is discussed. References 1HM Government, Dep. Business, Energy Ind. Strateg., 2020, 1–38. 2E. Pomerantseva, F. Bonaccorso, X. Feng, Y. Cui, Y. Gogotsi, Science, 2019, 366, 969. 3P. L. Cullen, K. M. Cox, M. K. Bin Subhan, L. Picco, O. D. Payton, D. J. Buckley, T. S. Miller, S. A. Hodge, N. T. Skipper, V. Tileli, C. A. Howard, Nat. Chem., 2017, 9, 244–249. 4A. Clancy, J. Melbourne, M. S. P. Shaffer, J. Mater. Chem. A, 2015, 3, 16708–16715. 5M. C. Watts, L. Picco, F. S. Russell-Pavier, P. L. Cullen, T. S. Miller, S. P. Bartus, O. D. Payton, N. T. Skipper, V. Tileli, C. A. Howard, Nature, 2019, 568, 216–220. Figure 1

Facile and Scalable Synthesis of Whiskered Gold Nanosheets for Stretchable, Conductive, and Biocompatible Nanocomposites.

Noble metal nanomaterials have been studied as conductive fillers for stretchable, conductive, and biocompatible nanocomposites. However, their performance as conductive filler materials is far from ideal because of their high percolation threshold and low intrinsic conductivity. Moreover, the difficulty in large-scale production is another critical hurdle in their practical applications. Here we report a method for the facile and scalable synthesis of whiskered gold nanosheets (W-AuNSs) for stretchable, conductive, and biocompatible nanocomposites and their application to stretchable bioelectrodes. W-AuNSs show a lower percolation threshold (1.56 vol %) than those of gold nanoparticles (5.02 vol %) and gold nanosheets (2.74 vol %), which enables the fabrication of W-AuNS-based stretchable nanocomposites with superior conductivity and high stretchability. Addition of platinum-coated W-AuNSs (W-AuNSs@Pt) to the prepared nanocomposite significantly reduces the impedance and improved charge storage capacity. Such enhanced performance of the stretchable nanocomposite enables us to fabricate stretchable bioelectrodes whose performance is demonstrated through animal experiments including electrophysiological recording and electrical stimulation in vivo.

Effects of Water and Nitrogen Management on Water Productivity, Nitrogen Use Efficiency and Leaching Loss in Rice Paddies

Effective water and nitrogen (N) management strategies are critical for sustainable agricultural development. Lysimeter experiments with two deep percolation rates (low percolation and high percolation, i.e., LP and HP: 3 mm d−1 and 5 mm d−1) and five N application levels (N0~N4: 0, 60, 135, 210 and 285 kg N ha−1) were conducted to investigate the effects of controlled drainage on water productivity (WP) and N use efficiency (NUE) in water-saving irrigated paddy fields. The results demonstrated that NH4+-N and NO3−-N were the major components of total nitrogen (TN) in ponded water and leachate, accounting for more than 77.1% and 83.6% of TN, respectively. The risk of N leaching loss increased significantly under treatment of high percolation rates or high N application levels. High percolation loss required greater irrigation input, thus reducing WP. In addition, N uptake increased with increasing N application, but fertilization applied in excess of crop demand had a negative effect on grain yield. NUE was affected by the amount of N applied and increased with decreasing N levels. Water and N application levels had a significant effect on N uptake of rice, but their interaction on N uptake or NUE was not significant. For the LP and HP regimes, the highest N uptake and WP were obtained with N application levels of 285 kg ha−1 and 210 kg ha−1, respectively. Our overall results suggested that the combination of controlled drainage and water-saving irrigation was a feasible mitigation strategy to reduce N losses through subdrainage percolation and to provide more nutrients available for rice to improve NUE, thus reducing diffuse agricultural pollution. Long-term field trials are necessary to validate the lysimeter results.

Biodegradable, biomimetic, and nanonet-engineered membranes enable high-flux and highly-efficient oil/water separation

Porous membranes with fascinating super-wettable surface and tunable porous architecture for oil-water separation have been developed rapidly, however, the serious secondary marine pollution caused by the non-degradable defectiveness of membranes themselves is still a thorny problem. Herein, we create an eco-friendly membrane with biomimetic cobweb-like nanostructure via assembling two-dimensional bacterial cellulose nanonets on the starch nanofibrous membrane on a large scale. The obtained novel composite membranes exhibit integrated properties of sub-micron pore size, ultrahigh porosity, superhydrophilicity, and underwater superoleophobicity, stemming from the synergistic effect of the hydrated nanonet-skin-layer and porous starch matrix. By virtue of the narrow-distributed sub-micron pores, ultrahigh porosity, and ultrathin thickness, the resulting membrane shows outstanding performance of excellent separation efficiency (up to 99.996%), high percolation flux (maximum of 15968 L m−2 h−1), well surpassing the conventional microfiltration membranes. More significantly, with the advantage of biodegradability and anti-oil-fouling property, the membrane could serve as the robust platform for long-term wastewater remediation.

The synergistic effect of micron spherical and flaky silver-coated copper for conductive adhesives to achieve high electrical conductivity with low percolation threshold

In the application of electronic products, it is critical for conductive adhesives to ensure high electrical conductivity and good adhesion reliability. In this study, isotropic conductive adhesives (ICAs) with high conductivity and low percolation threshold can be achieved by making full use of the synergistic effect of micron spherical and flaky silver-coated copper ([email protected]) conductive fillers. The flaky [email protected] powder prepared by electroless plating was chosen as the main conductive filler, and the spherical core-shell structure [email protected] powder was used as an auxiliary conductive filler to be dispersed in the flaky [email protected] particles, providing more possibilities for building a large number of conductive bridges. In this study, the [email protected] powder was synthesized to eliminate the disadvantages of Cu oxidation and Ag electrochemical migration, while making the ICAs low cost and favourable conductivity. Furthermore, the curing parameters were optimized for the matrix resin in corresponding experiments. The results showed that a combination of spherical and flaky [email protected] powders in ICAs could not only significantly reduce the percolation threshold and the bulk resistivity but also increase the shear strength compared with the single component. In particular, the bulk resistivity of the optimum sample was 1.95 × 10−3 Ω cm, and the shear strength was 22.69 MPa when the filler content was only 60 wt%. Hence, the ICAs filled with spherical and flaky [email protected] will pave the way for high-performance and low-cost ICAs in the electronics packaging industry.

Assessing soil water balance to optimize irrigation schedules of flood-irrigated maize fields with different cultivation histories in the arid region

Water availability is the most critical restriction for sustainable crop plantation in the arid region; consequently, it is essential to quantify the soil water balance and optimize the irrigation schedules in the farmland. However, the effects of cultivation history on crop field water balance and optimized irrigation design were rarely studied. In this study, three typical maize (Zea mays L.) fields with different cultivation histories (i.e., old oasis maize field, OF; new maize field developed from a wetland, NFW; new maize field developed from the desert, NFD) in arid regions of Northwest China were selected, which had major differences in soil textures and GWLs. Based on one growth season (i.e., from April 30th to September 30th) in situ field monitoring (e.g., soil water content, maize growth index, meteorological data) and numerical model (HYDRUS-1D) simulation, the water balance and root water uptake deficit in these fields were quantified, and optimized irrigation schedules were proposed. During the maize growth period under the current irrigation schedule, the highest percolation was observed in OF (364 mm), followed by NFD (231 mm) and NFW (−52 mm). The soil water in NFW was obviously recharged by the capillary rise from groundwater, while the OF and NFD were not. Also, the most severe water deficit was identified in NFD, followed by NFW and OF. Compared with the current irrigation schedule, the irrigation was reduced by 65%, 45%, and 13% under the optimized irrigation amount in NFW, OF, and NFD, respectively. Furthermore, it was reduced by 84%, 61%, and 23% under both irrigation time and amount optimized in NFW, OF, and NFD, respectively. Under either optimized irrigation, the water deficit was relieved, deep percolation was reduced during the maize growth period, and less soil water was stored after maize was harvested. Especially under irrigation time and amount optimizing, the least irrigation times (4) and amount (90 mm) were applied in NFW among three fields, ascribing to a large amount of water recharge from shallow groundwater by capillary rise. Due to the soil texture differences, fewer irrigation times (6) with considerable single irrigation amount (30–70 mm) was recommended for OF with loamy soil, whereas more irrigation times (12) with less single irrigation (25–50 mm) were appropriated for NFD with sandy soil. It concluded that the effects of soil texture and GWL should be well considered for optimizing irrigation schedules.

From Strain Stiffening to Softening-Rheological Characterization of Keratins 8 and 18 Networks Crosslinked via Electron Irradiation.

Networks of crosslinked keratin filaments are abundant in epithelial cells and tissues, providing resilience against mechanical forces and ensuring cellular integrity. Although studies of in vitro models of reconstituted keratin networks have revealed important mechanical aspects, the mechanical properties of crosslinked keratin structures remain poorly understood. Here, we exploited the power of electron beam irradiation (EBI) to crosslink in vitro networks of soft epithelial keratins 8 and 18 (k8–k18) filaments with different irradiation doses (30 kGy, 50 kGy, 80 kGy, 100 kGy, and 150 kGy). We combined bulk shear rheology with confocal microscopy to investigate the impact of crosslinking on the mechanical and structural properties of the resultant keratin gels. We found that irradiated keratin gels display higher linear elastic modulus than the unirradiated, entangled networks at all doses tested. However, at the high doses (80 kGy, 100 kGy, and 150 kGy), we observed a remarkable drop in the elastic modulus compared to 50 kGy. Intriguingly, the irradiation drastically changed the behavior for large, nonlinear deformations. While untreated keratin networks displayed a strong strain stiffening, increasing irradiation doses shifted the system to a strain softening behavior. In agreement with the rheological behavior in the linear regime, the confocal microscopy images revealed fully isotropic networks with high percolation in 30 kGy and 50 kGy-treated keratin samples, while irradiation with 100 kGy induced the formation of thick bundles and clusters. Our results demonstrate the impact of permanent crosslinking on k8–k18 mechanics and provide new insights into the potential contribution of intracellular covalent crosslinking to the loss of mechanical resilience in some human keratin diseases. These insights will also provide inspiration for the synthesis of new keratin-based biomaterials.

Prediction of piezoresistive sensitivity and percolation probability of synergetic CNT-GNP conductive network composite

A novel one-step Monte-Carlo approach considering the orientation effect of carbon nanotubes (CNTs) in synergism with uniformly distributed ellipsoidal graphene nanoplatelets (GNPs) teamed up with percolation model is developed to study the percolation probability and gauge factor of hybrid CNT-GNP piezoresistive conductive network composite. A representative volume element is generated based on the randomly oriented rod-like CNTs and uniformly distributed disk-shape GNPs to examine the piezoresistive sensitivity developed by strain under tension. The model predictions are compared with experimental studies related to electrical conductivity and piezoresistivity of hybrid CNT-GNP nanocomposites and a good agreement is achieved. A parametric investigation of the influences of CNT volume fraction, degree of orientation, GNP diameter and volume fraction is performed on the piezoresistive sensitivity of nanocomposite. High piezoresistive sensitivity is achieved for scattered short aligned CNTs distributed in the matrix with sparse low aspect ratio GNPs. The results also demonstrated that high percolation probability is achievable for nanocomposite with longer CNTs oriented in random directions and perfect dispersion of GNPs with higher surface area.