Increase In Permeability Research Articles

Young blood-mediated cerebromicrovascular rejuvenation through heterochronic parabiosis: enhancing blood-brain barrier integrity and capillarization in the aged mouse brain.

Age-related cerebromicrovascular changes, including blood-brain barrier (BBB) disruption and microvascular rarefaction, play a significant role in the development of vascular cognitive impairment (VCI) and neurodegenerative diseases. Utilizing the unique model of heterochronic parabiosis, which involves surgically joining young and old animals, we investigated the influence of systemic factors on these vascular changes. Our study employed heterochronic parabiosis to explore the effects of young and aged systemic environments on cerebromicrovascular aging in mice. We evaluated microvascular density and BBB integrity in parabiotic pairs equipped with chronic cranial windows, using intravital two-photon imaging techniques. Our results indicate that short-term exposure to young systemic factors leads to both functional and structural rejuvenation of cerebral microcirculation. Notably, we observed a marked decrease in capillary density and an increase in BBB permeability to fluorescent tracers in the cortices of aged mice undergoing isochronic parabiosis (20-month-old C57BL/6 mice [A-(A)]; 6 weeks of parabiosis), compared to young isochronic parabionts (6-month-old, [Y-(Y)]). However, aged heterochronic parabionts (A-(Y)) exposed to young blood exhibited a significant increase in cortical capillary density and restoration of BBB integrity. In contrast, young mice exposed to old blood from aged parabionts (Y-(A)) rapidly developed cerebromicrovascular aging traits, evidenced by reduced capillary density and increased BBB permeability. These findings underscore the profound impact of systemic factors in regulating cerebromicrovascular aging. The rejuvenation observed in the endothelium, following exposure to young blood, suggests the existence of anti-geronic elements that counteract microvascular aging. Conversely, pro-geronic factors in aged blood appear to accelerate cerebromicrovascular aging. Further research is needed to assess whether the rejuvenating effects of young blood factors could extend to other age-related cerebromicrovascular pathologies, such as microvascular amyloid deposition and increased microvascular fragility.

TiO2/AgBr nanocomposite as a novel hydrophilic and photocatalytic modifier in the fabrication of polyethersulfone membrane for wastewater treatment

Enhancing the performance of filtration membranes to improve their antifouling, permeability, and stability is a crucial objective. This can be acquired through the development of innovative materials and methods. With this in mind, the exertion of novel materials is considered a promising approach for modifying polymeric membranes. This study focuses on the potential of incorporating TiO2/AgBr photocatalytic nanocomposites to improve the hydrophilicity, antifouling, and permeability of polyethersulfone (PES) membranes. Following the synthesis of TiO2/AgBr, the study examines its impact on the performance of PES membranes by introducing various concentrations of TiO2/AgBr nanocomposite. Notably, the water contact angle significantly decreases from 68.5° to 44.2°, indicating an improvement in hydrophilicity. This enhanced overall porosity leads to almost a twofold increase in pure water permeability, with the bare membrane registering 78.3 L/m2h.bar and the membrane containing 0.2 wt% TiO2/AgBr achieving 152.4 L/m2h.bar. Due to the photocatalytic activity of TiO2/AgBr, the modified membranes demonstrate promoted antifouling performance, when UV irradiation is used in the washing step of the fouled membranes, as evidenced by the increased flux recovery ratio values, rising from 48 to 60.6 %. The rejection of two different dyes was assessed and the results of 83.9 % and 95.2 % rejection were obtained for Reactive Black 5 (RB5) and Lanasol Red 6G, respectively. Furthermore, the antibacterial activity of TiO2/AgBr was also indicated by confocal microscopy analysis. Thus, embedding TiO2/AgBr not only enhances antifouling properties but also improves the membranes’ ability to reject dyes effectively.

Effect of Metformin on Sertoli Cell Fatty Acid Metabolism and Blood–Testis Barrier Formation

Sertoli cells (SCs) are essential to maintaining germ cell development. Metformin, the main pharmacologic treatment for pediatric type 2 diabetes, is administered to children during SC maturation. The present study aimed to analyze whether metformin affects SC energy metabolism and blood–testis barrier (BTB) integrity. Primary SC cultures were used for the in vitro studies. In vivo effects were studied in Sprague–Dawley rats treated with 200 mg/kg metformin from Pnd14 to Pnd30. Metformin decreased fatty acid oxidation and increased 3-hydroxybutyrate production in vitro. Moreover, it decreased the transepithelial electrical resistance across the monolayer and induced ZO-1 redistribution, suggesting an alteration of cell junctions. In vivo, a mild but significant increase in BTB permeability and ZO-1 expression was observed in the metformin group, without changes in testicular histology and meiosis progression. Additionally, adult rats that received metformin treatment during the juvenile period showed no alteration in BTB permeability or daily sperm production. In conclusion, metformin exposure may affect BTB permeability in juvenile rats, but this seems not to influence spermatogenesis progression. Considering the results obtained in adult animals, it is possible to speculate that metformin treatment during the juvenile period does not affect testicular function in adulthood.

Formation integrity evaluation for geosequestration of CO2 in depleted petroleum reservoirs under cyclic stress conditions

The geological storage of carbon dioxide (CO2), also referred to as CO2 geosequestration, represents one of the most promising options for reducing greenhouse gases in the atmosphere. However, most of the time, CO2 is captured with small amounts of other industrial gases such as sulphur dioxide (SO2) and hydrogen sulphide (H2S), which might be compressed together and stored in depleted petroleum reservoirs or aquifers. Moreover, during CO2 geosequestration in reservoirs, pressure variations during injection could force some amount of CO2 (with or without other acid gas impurities) into the caprock; thereby, altering the petrophysical, geochemical, and geomechanical properties of the caprock. Thus, the brittleness index of the reservoir and caprock might be impacted during CO2 geosequestration due to the chemical reactions between the rock minerals and the formation fluid. Furthermore, to meet the world net-zero carbon target, the promotion of CO2 utilization is paramount. This could be possible by developing an effective technology for cyclic CO2 geosequestration (with or without gas impurities). Therefore, studies on the co-injection of CO2 with other acid gases from industrial emissions, their withdrawal from the porous medium, and their impact on reservoir and caprock integrity are paramount. In this study, a dual-tubing string well completion technology was designed for cyclic injection and withdrawal of CO2 (with or without another acid gas), and numerical simulations were performed using TOUGHREACT codes, to model the cyclic process and investigate the co-injection of SO2 and H2S (separately) with CO2 in sandstone formations overlain by shale caprock. A novel technique of converting the volume fraction of minerals to their weight fraction was developed in this study, to evaluate the brittleness index of the sandstone reservoir and shale caprock during CO2 geosequestration. The findings of the study indicate that the porosity and permeability increase for the CO2 only and CO2–H2S injection cases, in the shale caprock; while for the CO2–SO2 injection case, porosity and permeability only decreased in the layers of the shale caprock contacted by SO2 and due to anhydrite precipitation. In all the injection cases, the porosity and permeability of the sandstone reservoir decreased in a few layers directly below the perforation interval of the production zone. However, in other regions in the sandstone reservoir, the porosity and permeability increased for the CO2 only and CO2–H2S injection cases. In contrast, for the CO2–SO2 co-injection case, porosity and permeability decreased in the layers of the sandstone rock contacted by SO2. In all the CO2 geosequestration cases, the brittleness of the shale and sandstone rocks investigated decreased slightly, except in the CO2–SO2 co-injection case where the brittleness of the sandstone rock decreased significantly. Based on the mineralogical composition of the formations in this study, co-injection of SO2 gas with CO2 gas, only decreased the brittleness index of the shale caprock slightly, but significantly decreased the brittleness of the sandstone reservoir.

Numerical modelling of earthquake sequences involving valving and pumping of fluids

Summary Faults in the upper crust are sometimes thought to act as self-sealing valves, episodically releasing highly overpressured fluids trapped at greater depth during earthquakes. They are also often considered to be capable of actively pumping fluids into or out of faults in response to coseismic volumetric strain, thermal pressurisation or other mechanisms. In this study we investigate how these different types of behaviour (i.e., valve versus pump) are manifested in earthquakes. We do this using a two dimensional plane strain model where frictional sliding on a thrust fault that is fed by a fluid source at its base is coupled to porous flow, thermal pressurisation and strong variations in permeability. Our results show that thermal pressurisation leads to dramatic dynamic weakening that produces earthquakes that propagate as slip pulses producing large stress drop, large slip and high slip velocities. On the other hand, valve-type behaviour typically produces smaller, less energetic earthquakes that commonly arrest before rupturing the entire fault. In some valve-models, we observe complex compound ruptures and swarm activity, which is linked to the ascent of a propagating fluid pressure pulse driven by a large increase in permeability during sliding. Both pump and valve mechanisms can produce anomalously weak faults, though they are each associated with distinctly different fluid pressure and strength evolution over the seismic cycle and during rupture. Our models highlight the complex way in which fluids may interact with earthquakes, especially if valve and pump models coexist.

Physiologically based pharmacokinetic model for predicting the biodistribution of albumin nanoparticles after induction and recovery from acute lung injury

The application of nanomedicine in the treatment of acute lung injury (ALI) has great potential for the development of new therapeutic strategies. To gain insight into the kinetics of nanocarrier distribution upon time-dependent changes in tissue permeability after ALI induction in mice, we developed a physiologically based pharmacokinetic model for albumin nanoparticles (ANP). The model was calibrated using data from mice treated with intraperitoneal LPS (6 mg/kg), followed by intravenous ANP (0.5 mg/mouse or about 20.8 mg/kg) at 0.5, 6, and 24 h. The simulation results reproduced the experimental observations and indicated that the accumulation of ANP in the lungs increased, reaching a peak 6 h after LPS injury, whereas it decreased in the liver, kidney, and spleen. The model predicted that LPS caused an immediate (within the first 30 min) dramatic increase in lung and kidney tissue permeability, whereas splenic tissue permeability gradually increased over 24 h after LPS injection. This information can be used to design new therapies targeting specific organs affected by bacterial infections and potentially by other inflammatory insults.

Gelsenicine disrupted the intestinal barrier of Caenorhabditis elegans.

Gelsemium elegans Benth. (G. elegans) is a traditional medicinal herb that has anti-inflammatory, analgesic, sedative, and detumescence effects. However, it can also cause intestinal side effects such as abdominal pain and diarrhea. The toxicological mechanisms of gelsenicine are still unclear. The objective of this study was to assess enterotoxicity induced by gelsenicine in the nematodes Caenorhabditis elegans (C. elegans). The nematodes were treated with gelsenicine, and subsequently their growth, development, and locomotion behavior were evaluated. The targets of gelsenicine were predicted using PharmMapper. mRNA-seq was performed to verify the predicted targets. Intestinal permeability, ROS generation, and lipofuscin accumulation were measured. Additionally, the fluorescence intensities of GFP-labeled proteins involved in oxidative stress and unfolded protein response in endoplasmic reticulum (UPRER) were quantified. As a result, the treatment of gelsenicine resulted in the inhibition of nematode lifespan, as well as reductions in body length, width, and locomotion behavior. A total of 221 targets were predicted by PharmMapper, and 731 differentially expressed genes were screened out by mRNA-seq. GO and KEGG enrichment analysis revealed involvement in redox process and transmembrane transport. The permeability assay showed leakage of blue dye from the intestinal lumen into the body cavity. Abnormal mRNAs expression of gem-4, hmp-1, fil-2, and pho-1, which regulated intestinal development, absorption and catabolism, transmembrane transport, and apical junctions, was observed. Intestinal lipofuscin and ROS were increased, while sod-2 and isp-1 expressions were decreased. Multiple proteins in SKN-1/DAF-16 pathway were found to bind stably with gelsenicine in a predictive model. There was an up-regulation in the expression of SKN-1::GFP, while the nuclear translocation of DAF-16::GFP exhibited abnormality. The UPRER biomarker HSP-4::GFP was down-regulated. In conclusion, the treatment of gelsenicine resulted in the increase of nematode intestinal permeability. The toxicological mechanisms underlying this effect involved the disruption of intestinal barrier integrity, an imbalance between oxidative and antioxidant processes mediated by the SKN-1/DAF-16 pathway, and abnormal unfolded protein reaction.

The Metabolism, Detrimental Effects, and Signal Transduction Mechanism of Reactive Oxygen Species in Plants under Abiotic Stress

Plants are a major source of bio based materials, and their productivity is significantly impacted by environmental adversities with the continuous deterioration of the environment. The disruption of reactive oxygen species (ROS) production and scavenging balance is a common consequence of various abiotic stresses in plants, resulting in the excessive accumulation of ROS. However, it is crucial to acknowledging the dual role of ROS, acting both as harmful substances and signaling molecules. ROS can interact with membrane proteins, initiating a chain reaction of membrane lipid peroxidation. This process leads to a decrease in membrane lipid unsaturation and fluidity, as well as an increase in membrane permeability. Inhibited enzyme activity even lead to loss of protein function, caused DNA damage and mutations, blocked DNA replication and transcription, eventually leading to cell death. This can result in significant reductions in crop yield and biomass in bio based agricultural production. ROS also played vital role in signal molecule transduction in the process of plant resistance to stress, and worked in concert with other signal molecules to induce the stress resistance genes’ expression and enhance plant resistance. Hereto, scavenging mechanism for ROS in plants is of the essence to regulate the concentration of ROS, thus determining which role ROS play. The thermal dissipation of excess light energy effectively avoids ROS production, and the enzymatic and non-enzymatic antioxidant defense systems in plants work cooperatively to clear excessive ROS. This review provides a comprehensive summary of the production pathway, detrimental effects, scavenging mechanism and signal transduction of ROS in plants under abiotic stress.

Further Investigation of CO2 Quasi-Dry Fracturing in Shale Reservoirs—An Experimental Study

The physical properties of shale reservoirs are typically poor, necessitating the use of fracturing technology for effective development. However, the high clay content prevalent in shale formations poses significant challenges for conventional hydraulic fracturing methods. To address this issue, CO2-based fracturing fluid has been proposed as an alternative to mitigate the damage caused by water-based fracturing fluids. In this paper, the applicability of quasi-dry CO2 fracturing in shale reservoirs is examined from three key perspectives: the viscosity of CO2 fracturing fluid, the fracture characteristics induced by the CO2 fracture fluid, and the potential reservoir damage caused by the fracturing fluid. Firstly, the viscosity of CO2 fracturing fluid was determined by a rheological experiment. Rheological tests revealed that the viscosity of CO2 fracturing fluid was significantly influenced by the water–carbon ratio. Specifically, when the water–carbon ratio was 30:70, the maximum viscosity observed could reach 104 mPa·s. Moreover, increasing reservoir temperature resulted in decreased fracturing fluid viscosity, with a 40 °C temperature rise causing a 20% viscosity reduction. Secondly, matrix permeability tests were conducted to investigate permeability alteration during CO2 fracturing fluid invasion. Due to the weak acidity of CO2-based fracturing fluid, the permeability reduction induced by clay hydration was inhibited, and an increase in permeability was observed after a 3-day duration. However, the matrix permeability tends to decrease as the interaction time is prolonged, which means prolonged soaking time can still cause formation damage. Finally, triaxial fracturing experiments facilitated by a three-axis servo pressure device were conducted. The fracture properties were characterized using computed tomography (CT), and 3D reconstruction of fractured samples was conducted based on the CT data. The results demonstrate that CO2 fracturing fluid effectively activates weak cementation surfaces in the rock, promoting the formation of larger and more complex fractures. Hence, CO2 quasi-dry fracturing technology emerges as a method with significant potential, capable of efficiently stimulating shale reservoirs, although a reasonable soaking time is necessary to maximize hydrocarbon production.

Performance Characteristics and Optimization of a Single-Stage Direct Air Capture Membrane System in Terms of Process Energy Intensity

The increase in emissions and concentration of carbon dioxide in the atmosphere necessitates the implementation of direct carbon dioxide capture technologies. The article presents the characteristics of a single-stage membrane unit for the direct capture of carbon dioxide from the air. A membrane with a selectivity of αCO2/N2=70 and permeability PCO2=108m3(STP)(m2·h·bar) is chosen as the reference variant. It is demonstrated that increasing the pressure difference in the system by reducing the pressure of the permeate stream results in an improvement of all analyzed parameters. Manipulating both the membrane surface and its CO2 permeability yields similar results. With an increase in permeability or membrane surface area, the proportion of CO2 in the retentate and permeate decreases, while the degree of carbon dioxide recovery increases. However, the energy intensity of the process is a complex issue due to the presence of a local minimum in the obtained characteristics. Therefore, a relationship between the constants of energy intensity values for the separation process on the surface area field and CO2 membrane permeability is presented. The minimum energy intensity of the process obtained is 22.5 kWh/kgCO2. The CO2 content in the retentate for all analyses did not exceed 280 ppm.

Nanomorphogenesis of polyamide membranes by regulating activator-inhibitor diffusivity difference

The use of nanofiltration (NF) membranes featuring crumpled polyamide layers with excellent permeance and selectivity is promising for efficient water reclamation. Although diffusion-driven instability has been regarded as the key mechanism for forming crumpled polyamide structures, in-depth analyses of the morphological and structural features of these membranes are still lacking. We used ammonium carboxymethylcellulose (CMC) and glutaraldehyde (GA) to crosslink and form a pH-responsive interlayer to manipulate the interfacial polymerization (IP) process and the microstructures of interlayered thin-film composite (TFNi) membranes. Experimental observations and molecular dynamics simulations indicate a transition point in the spatial patterns from irregular to regular polyamide nanostructures by tuning the diffusivity difference between the reactant monomers in the two immiscible phases during the IP process. Compared with irregularly crumpled TFNi membranes, regularly crumpled TFNi membranes exhibited polyamide layers with higher aspect ratios (i.e., height/lateral dimension), potentially offering an increased filtration area and sufficient nanovoids. TFNi membranes exhibited a 2.5-fold increase in permeance compared to pristine polyamide membranes, along with twice the selectivity (up to 87.2) for Cl−/SO42−. Our work provides molecular insights into the tuning of morphological features and membrane performance of crumpled polyamide membranes.

Study on the influence law of gangue filling structure on the gas emission in adjacent coal seams

Gangue filling affects the emission and migration of gas in adjacent coal seams by altering the distribution of mine pressure in the stope. In engineering practice, the filling rate of gangue in the goaf fluctuates under the influence of external factors, leading to the formation of filling structures. However, the relationship between different filling structures and the gas emission law of adjacent coal seams remains unclear. The parameters affecting the gangue filling structure can be controlled or optimized in field practice. Meanwhile, these parameters are not independent of but correlated with each other. This study aims to control gas emission and improve the gas extraction of adjacent coal seams. Therefore, the gangue filling structure index ξ was proposed, and the permeability evolution of adjacent coal seams under different ξ and parameters was analyzed. The respective and coupling effects of the parameters composing ξ were further investigated by response surface methodology. The results revealed the parameters that have dominant effects on pressure relief and permeability increase of adjacent coal seams and their sequence of importance. Finally, the study proposed a technology that combines targeted gas extraction with geophysical prospecting methodologies. The research results provide a theoretical reference for engineering practice.

Modulation of intestinal epithelial permeability by chronic small intestinal helminth infections.

Increased permeability of the intestinal epithelial layer is linked to the pathogenesis and perpetuation of a wide range of intestinal and extra-intestinal diseases. Infecting humans with controlled doses of helminths, such as human hookworm (termed hookworm therapy), is proposed as a treatment for many of the same diseases. Helminths induce immunoregulatory changes in their host which could decrease epithelial permeability, which is highlighted as a potential mechanism through which helminths treat disease. Despite this, the influence of a chronic helminth infection on epithelial permeability remains unclear. This study uses the chronically infecting intestinal helminth Heligmosomoides polygyrus to reveal alterations in the expression of intestinal tight junction proteins and epithelial permeability during the infection course. In the acute infection phase (1 week postinfection), an increase in intestinal epithelial permeability is observed. Consistent with this finding, jejunal claudin-2 is upregulated and tricellulin is downregulated. By contrast, in the chronic infection phase (6 weeks postinfection), colonic claudin-1 is upregulated and epithelial permeability decreases. Importantly, this study also investigates changes in epithelial permeability in a small human cohort experimentally challenged with the human hookworm, Necator americanus. It demonstrates a trend toward small intestinal permeability increasing in the acute infection phase (8 weeks postinfection), and colonic and whole gut permeability decreasing in the chronic infection phase (24 weeks postinfection), suggesting a conserved epithelial response between humans and mice. In summary, our findings demonstrate dynamic changes in epithelial permeability during a chronic helminth infection and provide another plausible mechanism by which chronic helminth infections could be utilized to treat disease.

The role of morphine- and fentanyl-induced impairment of intestinal epithelial antibacterial activity in dysbiosis and its impact on the microbiota-gut-brain axis.

Recent evidence suggests that chronic exposure to opioid analgesics such as morphine disrupts the intestinal epithelial layer and causes intestinal dysbiosis. Depleting gut bacteria can preclude the development of tolerance to opioid-induced antinociception, suggesting an important role of the gut-brain axis in mediating opioid effects. The mechanism underlying opioid-induced dysbiosis, however, remains unclear. Host-produced antimicrobial peptides (AMPs) are critical for the integrity of the intestinal epithelial barrier as they prevent the pathogenesis of the enteric microbiota. Here, we report that chronic morphine or fentanyl exposure reduces the antimicrobial activity in the ileum, resulting in changes in the composition of bacteria. Fecal samples from morphine-treated mice had increased levels of Akkermansia muciniphila with a shift in the abundance ratio of Firmicutes and Bacteroidetes. Fecal microbial transplant (FMT) from morphine-naïve mice or oral supplementation with butyrate restored (a) the antimicrobial activity, (b) the expression of the antimicrobial peptide, Reg3γ, (c) prevented the increase in intestinal permeability and (d) prevented the development of antinociceptive tolerance in morphine-dependent mice. Improved epithelial barrier function with FMT or butyrate prevented the enrichment of the mucin-degrading A. muciniphila in morphine-dependent mice. These data implicate impairment of the antimicrobial activity of the intestinal epithelium as a mechanism by which opioids disrupt the microbiota-gut-brain axis.

Assessing the progress of internal instability of fill dam material in South Korea through long-term seepage tests

Several studies investigating the internal instability of well-graded soils have suggested that well-graded soils show characteristics and developments different from those of gap-graded soils. Moreover, the cause and progression of long-term internal instability in well-graded soils have not yet been established. This study aimed to address this knowledge gap by conducting long-term seepage tests to analyze the progress and cause of the internal instability of well-graded soils generally utilized in fill dams in South Korea. The test results revealed that well-graded soils in internally stable conditions exhibited clogging due to fine particles, reducing overall permeability. A similar phenomenon was identified under internally unstable conditions. The subsequent unclogging process resulted in a rapid increase in permeability and erosion rate with the collapse of the soil structure. Consequently, the internal instabilities of well-graded soils progress through suffosion. Based on the test results, the mechanism of internal instability and its progression in well-graded soils were proposed.

Polynorbornenes with carbocyclic substituents: A perspective approach to highly permeable gas separation membranes

Gas transport properties of two sets of polynorbornenes bearing carbocyclic substituents of different nature (cyclohexyl, norbornyl, phenyl groups, and framed oligocyclic moieties) were systematically studied. The influence of side chain carbocyclic substituents on gas permeability and separation selectivity for CO2-containing gas pairs and gaseous hydrocarbons was evaluated. It was found that the presence of carbocyclic moieties in side chains of polynorbornenes promotes the increase in gas permeability similarly to that of SiMe3 groups, with this effect being enhanced by the increase in the number of cycles in the substituents. As a result, P(CO2) of the metathesis polymer with pentacene-based substituents is equal to 1200 Barrer. Studied polynorbornenes with carbocyclic substituents displayed promising gas separation selectivities: CO2/N2 separation selectivity up to 41 (above the 2008 upper bound in the Robeson diagram) and solubility-controlled hydrocarbon separation selectivity up to 16 for the n-butane/methane gas pair. For the polymer with pentacene-based substituents, the separation of the mixture of hydrocarbons and aging were studied. The studies revealed that the mixed gas C4/C1 separation selectivity of this polymer reaches 4, and a two-time reduction of permeability occurs in 8.5 months. Therefore, the incorporation of carbocyclic groups in the side chains of polynorbornenes can be considered as an efficient strategy for the design of polymeric gas separation membrane materials.

Stretched sapwood, ultra-widening permeability, and ditching da Vinci: revising models of plant form and function.

The mechanisms leading to dieback and death of trees under drought remains unclear. For constructing an understanding of these mechanisms, addressing major empirical gaps regarding tree structure-function relations remains essential. We give reasons to think that a central factor shaping plant form and function is selection favoring both constant leaf specific conductance with height growth and isometric (1:1) scaling between leaf area and the volume of metabolically active sink tissues ("sapwood"). Sapwood volume-leaf area isometry implies that per-leaf area sapwood volumes become transversely narrower with height growth; we call this "stretching." Stretching means that selection must favor increases in permeability above and beyond that afforded by tip-to-base conduit widening (ultra-widening permeability), as via fewer and wider vessels or tracheids with larger pits or larger margo openings. Leaf area-metabolically active sink tissue isometry would mean that it is unlikely that larger trees die during drought because of carbon starvation due to greater sink-source relationships as compared to shorter plants. Instead, increase in permeability is most plausibly associated with greater risk of embolism, and this seems a likelier culprit of the preferential vulnerability of larger trees to climate change-induced drought. Other implications of selection favoring constant per-leaf area sapwood construction and maintenance costs are departure from the da Vinci rule expectation of similar sapwood areas across branching orders, and that extensive conduit furcation in the stem seems unlikely. Because all of these considerations impact the likelihood of vulnerability to hydraulic failure versus carbon starvation, both implicated as key suspects in forest mortality, we suggest that these predictions represent essential priorities for empirical testing.

Antifouling performance enhancement of PES membranes using hydrophilic nanoparticles of poly(dopamine-acrylate) for oil/water separation

Polydopamine-acrylate (P(A-D)x) nanoparticles were blended with polyethersulfone (PES) to fabricate a high-performance hybrid ultrafiltration (UF) membrane for the separation of water from oily wastewater. In tris-alkaline buffer solution at room temperature, P(A-D)x nanoparticles were synthesized by intramolecular Michael addition of dopamine with acrylic acid (AA) monomers. Hybrid PES membranes were prepared using P(A-D)x at 0.05–0.4 wt% and characterized using various assays including Field emission scanning electron microscopy (FESEM), Thermogravimetric analysis (TGA), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and water contact angle (WCA). The membranes showed a significant increase in hydrophilicity, water permeability, and oil rejection (R). The primary and secondary pure water fluxes of the membrane with 0.2 wt% P(A-D)0.25 were 45% and 110.78% higher than those of neat PES membrane, respectively. For 3300 ppm oil feed solution, water flux during water/oil separation increased by 107%, while the oil rejection (R) remained at 99.08%. The surface of membrane was markedly hydrophilic, with a WCA about 40°, much lower than that of the neat PES membrane (80.67°). UF hybrid membranes also showed a remarkable reduction in oil adhesion on the membrane surface as well as superior antifouling performance for membranes containing 0.2 wt% P(A-D)0.25, flux recovery ratio (FRR) = 84.88 ± 3.27%, reversible fouling (Rr) = 51.12 ± 1.09%, and irreversible fouling (Rir) = 15.12 ± 3.27%. In addition, the pure water flux was 446% higher than that of the unmodified membrane after five cycles (900 minutes).

Altered lactate/pyruvate ratio may be responsible for aging-associated intestinal barrier dysfunction in male rats.

Some evidence points to a link between aging-related increased intestinal permeability and mitochondrial dysfunction in in-vivo models. Several studies have also demonstrated age-related accumulation of the of specific deletion 4834-bp of "common" mitochondrial DNA (mtDNA) in various rat tissues and suggest that this deletion may disrupt mitochondrial metabolism. The present study aimed to investigate possible associations among the mitochondrial DNA (mtDNA) common deletion, mitochondrial function, intestinal permeability, and aging in rats. The study was performed on the intestinal tissue from (24months) and young (4months) rats. mtDNA4834 deletion, mtDNA copy number, mitochondrial membrane potential, and ATP, lactate and pyruvate levels were analyzed in tissue samples. Zonulin and intestinal fatty acid-binding protein (I-FABP) levels were also evaluated in serum. Serum zonulin and I-FABP levels were significantly higher in 24-month-old rats than 4-month-old rats (p = 0.04, p = 0.026, respectively). There is not significant difference in mtDNA4834 copy levels was observed between the old and young intestinal tissues (p > 0.05). The intestinal mitochondrial DNA copy number was similar between the two age groups (p > 0.05). No significant difference was observed in ATP levels in the intestinal tissue lysates between old and young rats (p > 0.05). ATP levels in isolated mitochondria from both groups were also similar. Analysis of MMP using JC-10 in intestinal tissue mitochondria showed that mitochondrial membrane potentials (red/green ratios) were similar between the two age groups (p > 0.05). Pyruvate tended to be higher in the 24-month-old rat group and the L/P ratio was found to be approximately threefold lower in the intestinal tissue of the older rats compared to the younger rats (p < 0.002). The tissue lactate/pyruvate ratio (L/P) was three times lower in old rats than in young rats. Additionally, there were significant negative correlations between intestinal permeability parameters and L/P ratios. The intestinal tissues of aged rats are not prone to accumulate mtDNA common deletion, we suggest that this mutation does not explain the age-related increase in intestinal permeability. It seems to be more likely that altered glycolytic capacity could be a link to increased intestinal permeability with age. This observation strengthens assertions that the balance between glycolysis and mitochondrial metabolism may play a critical role in intestinal barrier functions.

Feasibility of measuring blood-brain barrier permeability using ultra-short echo time radial magnetic resonance imaging.

The purpose of this study is to evaluate the feasibility of using 3-dimensional (3D) ultra-short echo time (UTE) radial imaging method for measurement of the permeability of the blood-brain barrier (BBB) to gadolinium-based contrast agent. In this study, we propose to use the golden-angle radial sparse parallel (GRASP) method with 3D center-out trajectories for UTE, hence named as 3D UTE-GRASP. We first examined the feasibility of using 3D UTE-GRASP dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) for differentiating subtle BBB disruptions induced by focused ultrasound (FUS). Then, we examined the BBB permeability changes in Alzheimer's disease (AD) pathology using Alzheimer's disease transgenic mice (5xFAD) at different ages. For FUS experiments, we used four Sprague Dawley rats at similar ages where we compared BBB permeability of each rat receiving the FUS sonication with different acoustic power (0.4-1.0MPa). For AD transgenic mice experiments, we included three 5xFAD mice (6, 12, and 16 months old) and three wild-type mice (4, 8, and 12 months old). The result from FUS experiments showed a progressive increase in BBB permeability with increase of acoustic power (p <.05), demonstrating the sensitivity of DCE-MRI method for detecting subtle changes in BBB disruption. Our AD transgenic mice experiments suggest an early BBB disruption in 5xFAD mice, which is further impaired with aging. The results in this study substantiate the feasibility of using the proposed 3D UTE-GRASP method for detecting subtle BBB permeability changes expected in neurodegenerative diseases, such as AD.