External Concentration Research Articles

Flame retardant and mechanical properties of core‐shell‐like polybutylene terephthalate/intumescent flame retardant through controlling injection time

AbstractThis study prepared layered intumescent flame retardant (IFR)‐graphene oxide (GO) via the esterification of GO and IFR. Then the distribution of IFR‐GO in polybutylene terephthalate (PBT) was regulated via an injection molding process, while the tensile strength and combustion were explored. The results showed that the flame retardant distribution in PBT presented high external concentrations and low internal concentrations when the injection time was reduced. The lowest flame retardant content of 20 wt% was evident at an injection time of 2 s while displaying a high limiting oxygen index of 27.1. Although this resulted in a V‐0 flame‐retardant level, the mechanical properties were not affected. Therefore, the flame retardant was proportionately reduced by a shorter injection time to form a concentration gradient core‐shell‐like macrostructure, significantly increasing the flame‐resistant efficiency while retaining the mechanical properties.

Effects of impurity factor on the physical and transport properties for Ga1-xAlxAs quantum wire in the presence of Rashba spin-orbit interaction

There is a need to get familiarized with a systematic and precise approach to study the energy dispersion and ballistic conductance in a Ga1-xAlxAs quantum wire. We have employed parabolic confinement in this work. The combined impacts of Rashba spin orbit interaction (RSOI), external electric field, magnetic field, and Aluminium concentration on energy dispersion and conductivity in a Ga1-xAlxAs quantum wire have been explored. The Energy eigenvalues and eigenvectors are quantified using the diagonalization method and the transport properties are computed by Landuer-Bttiker formalism. It is noticed that the external electric field, magnetic field, Rashba spin-orbit interaction, and Aluminium concentration (impurity factor x) alter the energy spectra and conductivity. Hence, these parameters significantly affect the physical and transport properties.

Luminometric Studies of Yeast Response to Complex Environmental Calcium Variations Demonstrate Sensing of External Calcium Ion Changes

The response of yeast to sharp environmental increases in calcium concentration has been extensively studied. However, systematic studies of the response under more general changes are still lacking. Only limited exploration of cellular responses has been conducted where calcium concentration is decreased. This article describes a set of luminometric experiments that monitor the cytosolic calcium concentration under changing external concentration conditions. As a decrease in external calcium concentrations requires the use of large sample volumes, the experiments require the use of equipment adapted for this purpose. We describe the modification of commercial luminometric equipment to make the exploration possible. We explore the yeast cellular behavior when an increase in external calcium concentration is followed by a decrease in external calcium concentration. We compare these results with those from the case of a double pulse of concentration increase. Results from the experiment show that the first, concentration increasing pulse produces the well-known sharp increase in cytosolic calcium followed by calcium sequestration to return to a cytosolic concentration near its initial condition. Surprisingly, the calcium decrease step shows similar results with a cytosolic increase followed by a return to lower levels. The results suggest the presence of a calcium sensing mechanism regulating calcium influx from external sources. This mechanism would produce channel opening as a response to any changes in external concentration, be it an enhancement or a depletion.

Functional identification of bHLH transcription factor MdSAT1 in the ammonium response

Plants mainly uptake inorganic nitrogen from soil as ammonium and nitrate. Less energy is required to assimilate ammonium compared to nitrates, and plants prefer to take up ammonium when the external nitrogen concentration is low. Investigating the patterns and mechanisms of ammonium absorption can help improve crop nitrogen utilization. In this study, we isolated <italic>MdSAT1</italic>, a gene of apple encoding an ammonium-responsive bHLH transcription factor. MdSAT1 promoted the growth and development of lateral roots and root hairs. Overexpression of <italic>MdSAT1</italic> increased the transcript levels of genes related to ammonium uptake, indicating that MdSAT1 can regulate ammonium uptake and utilization at the transcriptional level. MdSAT1 also can modulate ROS accumulation to ultimately regulate plant growth. Taken together, these findings provide insight for us to further study the mechanisms by which <italic>MdSAT1</italic> controls ammonium utilization as well as plant growth and development.

Factors Affecting the Financial Performance: A Case of Microfinance Institutions in Ethiopia

Micro finance institutions in Ethiopia have shown a remarkable qualitative and quantitative growth since the early 1990s. It is increasingly understood that adequate financial services such as loans, saving products, insurance and payment services for the broad population, poor farmers and MSEs, promote quality and productivity. Thus, this study examined and presented the most prominent factors of financial performance of microfinance institutions in Ethiopia by using panel data. From a total population of 38 MFIs operating in Ethiopia; the study selected 17 microfinance institutions which are operating in the period 2011 to 2018. The fixed effect model was used after running a Hausman test. ROA was used as a proxy for the financial performance measurement and the study used the internal and external factors. Based on the regression analysis, the internal variable like age of microfinance institutions was showed to be significant variables with positive relationship to ROA and other internal variables such as capital to asset ratio and debt to equity ratio were found to be statistically negatively significant. But operational efficiency, portfolio quality and size of microfinance institutions were found to have insignificant effect on ROA. On the other hand, the only external variable market concentration was insignificant factors of microfinance institution in the study period. Based on the regression outcome, the study concluded that the management of the microfinance institutions may develop sound mobilizing savings campaign strategy in order to collect adequate savings from depositors and mostly operate on membership contribution to enhance MFI’s capital for ensuring unexpected losses and also MFI managers should develop the efficiency of operations from year to year.

Analysis of Indoor Air Pollutants and Guidelines for Space and Physical Activities in Multi-Purpose Activity Space of Elementary Schools

Owing to the recent increase in the number of warning reports and alerts on the dangers of fine dusts, there has been an increasing concern over fine dusts among citizens. In spaces with poor ventilation, the occupants are forced to open the window to initiate natural ventilation via the direct introduction of the outside air; however, this may pose a serious challenge if the external fine-dust concentration is high. The lack of natural ventilation increases the indoor carbon dioxide (CO2) concentration, thus necessitating the installation of mechanical ventilation systems. This study analyzed the frequency of the application of mechanical ventilation systems in the Multi-purpose activity space of elementary schools, which are spaces where children require a higher indoor air quality than adults owing to the rapid increase in the CO2 concentration of the Multi-purpose activity space during activities. In addition, the architectural and equipment factors of the Multi-purpose activity spaces of nine elementary schools were characterized. The results revealed that five out of the nine elementary schools installed mechanical ventilation systems, whereas the remaining four schools installed jet air turnover systems. The indoor air quality of the Multi-purpose activity space of D elementary school, which had the minimum facility volume among the schools investigated in this study (564.2 m3), with up to 32 participants for each activity, was investigated. The results revealed that the ultrafine-dust (PM2.5) concentration of the facility was as high as 4.75 µg/m3 at a height of 1.2 m, and the CO2 concentration was as high as 3183 ppm. The results of the analysis of three elementary schools with different volumes were compared and analyzed using CONTAM simulation. This study determined the required volume per occupant and the optimum number of occupants for a given volume and presented guidelines for the optimum number of occupants, activities, and volume to reduce the high concentration of pollutants in the analyzed Multi-purpose activity space. The guideline proposed in this study is aimed at maintaining the CO2 concentration of the Multi-purpose activity space below 1000 ppm, as prescribed by the Indoor Air Quality Control in Public-Use Facilities, Etc. Act in South Korea.

Expression of some salt tolerance genes isolated from Egyptian gray mangrove (Avicennia marina)

Mangroves are well-adapted halophytes that thrive in coastal saline environments. They live under difficult environmental conditions, such as high light intensity and external salt concentrations, as well as low-oxygen environments, such as water-logged muck, that are typically inappropriate for the survival of other plants. Salinity is a major abiotic factor that affects plant growth, productivity, and dispersal in tropical and semitropical intertidal areas. Furthermore, it affects approximately 20% of all cultivable land and 50% of all irrigated land on the planet. Mangroves have developed a sophisticated salt filtration mechanism and a complicated root structure to withstand salty water exposure and tidal movement. The expression patterns of five salt tolerance genes (amFer1, amDhna, amSod1, amCat1, and amUbc2) in the Egyptian gray mangrove (Avicennia marina Forssk.) grown under different environmental conditions in South Sinai protectorates (Nabq, Ras Mohamed, Safaga, and Wadi El-Gemal), Egypt, were investigated in this study. This study aimed to assess and examine the genetic behavior of mangroves in response to salinity by using quantitative real-time PCR. Findings revealed differences in the expression patterns of the investigated genes under various conditions, showing that salinity influences plant genetic response. Ferritin gene expression was high in all locations, indicating that ferritin represents an essential component of the mangrove response mechanisms.

Simultaneous Monitoring of pH and Chloride (Cl-) in Brain Slices of Transgenic Mice.

Optosensorics is the direction of research possessing the possibility of non-invasive monitoring of the concentration of intracellular ions or activity of intracellular components using specific biosensors. In recent years, genetically encoded proteins have been used as effective optosensory means. These probes possess fluorophore groups capable of changing fluorescence when interacting with certain ions or molecules. For monitoring of intracellular concentrations of chloride ([Cl−]i) and hydrogen ([H+] i) the construct, called ClopHensor, which consists of a H+- and Cl−-sensitive variant of the enhanced green fluorescent protein (E2GFP) fused with a monomeric red fluorescent protein (mDsRed) has been proposed. We recently developed a line of transgenic mice expressing ClopHensor in neurons and obtained the map of its expression in different areas of the brain. The purpose of this study was to examine the effectiveness of transgenic mice expressing ClopHensor for estimation of [H+]i and [Cl−]i concentrations in neurons of brain slices. We performed simultaneous monitoring of [H+]i and [Cl−]i under different experimental conditions including changing of external concentrations of ions (Ca2+, Cl−, K+, Na+) and synaptic stimulation of Shaffer’s collaterals of hippocampal slices. The results obtained illuminate different pathways of regulation of Cl− and pH equilibrium in neurons and demonstrate that transgenic mice expressing ClopHensor represent a reliable tool for non-invasive simultaneous monitoring of intracellular Cl− and pH.

Effect of weak solute advection on a chemically active particle under the influence of an external concentration gradient

A Janus particle is an example of a micro swimmer which converts chemical energy present in the environment to its mechanical energy using surface reaction. In this work, we theoretically study the weak effect of solute advection on the swimming velocity of an active particle. Using the method of matched asymptotic expansion we provide a general framework for calculating first order corrections to the concentration field and the swimming velocity of an active particle in terms of Peclet number relative strength of advection to diffusion. The O(Pe) corrections reduce the magnitude of swimming velocity independent of other parameters

Identification and pharmacological characterization of histamine-gated chloride channels in the fall armyworm, Spodoptera frugiperda

Histamine-gated chloride channels (HACls) mediate fast inhibitory neurotransmission in invertebrate nervous systems and have important roles in light reception, color processing, temperature preference and light-dark cycle. The fall armyworm, Spodoptera frugiperda is a main destructive pest of grain and row crops. However, the pharmacological characterization of HACls in S. frugiperda remain unknown. In this study, we identified two cDNAs encoding SfHACl1 and SfHACl2 in S. frugiperda. They had similar expression patterns and were most abundantly expressed in the head of larvae and at the egg stage. Electrophysiological analysis with the two-electrode voltage clamp method showed that histamine (HA) and γ-aminobutyric acid (GABA) activated inward currents when SfHACls were singly or collectively expressed with different ratios in Xenopus laevis oocytes. These channels were ≥2000-fold more sensitive to HA than to GABA. They were anion-selective channels, which were highly dependent on changes in external chloride concentrations, but insensitive to changes in external sodium concentrations. The insecticides abamectin (ABM) and emamectin benzoate (EB) also activated these channels with the EC50 to SfHACl1 lower than that to SfHACl2. And the EC50s of ABM and EB to the co-expressed channels gradually increased with increase in the injection ratio of SfHACl2 cRNA. Homology models and docking simulations revealed that HA bound to the large amino-terminal extracellular domain of SfHACl1 and SfHACl2 by forming 4 and 2 hydrogen bonds, respectively. The docking simulations of ABM and EB had similar binding sites in the transmembrane regions. Overall, these findings indicated that HACls act as targets for macrolide, and this study provides theoretical guidance for further derivatization of abamectin insecticides.

Numerical simulation on response characteristics of coal ignition under the disturbance of fluctuating heat

Owing to coal commonly existing in a fluctuating thermal environment, a two–step parallel reaction model for coal ignition was established to explore the development of coal ignition under fluctuating thermal convection, fluctuating thermal radiation, and convection–radiation coupling (CRC). To be specific, this included temperature evolution in a coal mass and fluctuating periodic characteristics. The nonlinear gain of coal spontaneous combustion caused by oscillatory heat flux conditions was researched. The results show that the thermal fluctuation at 0.1 Hz is conducive to coal ignition. The ignition delay time (IDT) exponentially decreases with the growth of both the thermal convection velocity and radiation heat flux. Under external thermal disturbance, the temperature, convection velocity, oxygen concentration, and depth of the sensitive area all vary periodically. Under different types of heat disturbance, the temperature and convection velocity fluctuate with an increasing trend, while the oxygen concentration fluctuates with a decreasing trend. There is a low phase difference between the temperature and the convection velocity while the phase difference between the temperature and oxygen concentration is about 90° Besides, the peak fluctuation of the oxidation rate of coal changes inversely with the depth of fluctuations of the sensitive area.

Effects of atmospheric CO2 on canopy uptake of gaseous ammonia by tomato (Lycopersicum esculentum Mill.) in polytunnel vegetable production systems

Plant-atmosphere NH3 exchange is normally present in plastic-shed vegetable production systems, very limited information is currently available on how NH3 absorption responds to CO2 concentration changes. Tomato plants at the fruit setting stage were randomly selected from a field and transferred to a closed circulation system. Using an isotope gas dilution procedure (1:50-fold dilution) to inject different volumes of 13CO2 and 15NH3, we maintained the CO2 concentration in the system at 200, 400 or 800 ppm for 1 h, while the NH3 concentration was maintained at 20 or 100 ppm. Using this system, we studied the effects of different CO2 concentration on NH3 absorption by tomato leaves during the planting period in autumn and winter. With an increased carbon dioxide (CO2) concentration, the ammonia (NH3) uptake of a tomato (Lycopersicum esculentum Mill.) canopy increased significantly (P < 0.05) and carbon (C) accumulation increased accordingly. Compared with a low NH3 environment, a high NH3 environment significantly increased the NH3 uptake of a plant canopy (P < 0.05), but under a C800 treatment it decreased significantly. Under two different NH3 environments, the NH4+ concentration and pH in tomato leaf apoplasts decreased significantly with an increase in the CO2 concentration (P < 0.05), and the NH3 compensation point (χNH3) gradually decreased (P < 0.05). In a low NH3 environment (N20), compared with the C400 treatment, NH3 absorption was reduced by 34.9% in the C800 treatment, whereas in a high NH3 environment (N100) it was reduced by 32.2%. A redundancy analysis (RDA) and path analysis showed that the influence of the CO2 concentration on canopy NH3 absorption was mainly achieved by changing the direct effect of the χNH3 [although the stomatal conductance (Gs) decreased with an increase in the CO2 concentration]. The response of a lower χNH3 to elevated CO2 will increase the absorption and utilization of NH3volatilised from the soil into the air by tomato leaves in a greenhouse. It was therefore shown that the NH3 absorption by a greenhouse tomato canopy was simultaneously affected by changes in the external NH3 and CO2 concentrations, and increased with an increase in C accumulation.

A study of variables that affect the process of sulfate attack of cement‐based materials subjected to stray current

AbstractDurability is one of the most important considerations for subway structures. However, the cement‐based materials used in subway engineering can be jeopardized by sulfate and the stray current and therefore can be subjected to severe damage during service. This study aims to investigate the degradation process of cement‐based materials exposed to stray current and external sulfate. In particular, the effects of three key variables were evaluated: concentration of external sulfate solution, level of stray current and cement type. After exposure, the visual appearance, compressive strength, SO42− profiles and microstructure of cement‐based materials were analyzed. Moreover, the amounts of degradation products were measured to evaluate the influencing degree of different variables and further explain the degradation mechanisms. Experimental results of this study reveal that (a) sulfate attack was related to the external sulfate concentration, but the relation was changed due to the presence of stray current. One explanation is that sulfate ions can be quickly accumulated in the pores of cement‐based materials under the effect of stray current, which makes the chemical reaction of sulfate attack exchange from diffusion control to reaction control. (b) Stray current could accelerate external sulfate attack of cement‐based materials, and the greater the stray current, the more severe sulfate attack was induced. (c) Compared with P·I type cement, high sulfate resistant (HSR) cement showed a better resistance to external sulfate attack. (iv) And, the main degradation products, ettringite and gypsum, were observed in specimens after exposure. Additionally, stray current might induce the decomposition of ettringite. It should be paid more attention on the durability of cement‐based materials exposed to the coupled conditions of stray current and sulfate.

Nitrogen and Phosphorus Diffusion Fluxes: Insight from High-Resolution Technology and Hydrodynamic Modeling

Nitrogen and phosphorus are key elements in controlling eutrophication in the aquatic system. Water and sediment samples were collected from Hongfeng Lake, a seasonally stratified reservoir in southwest China, in winter and summer. Diffusion fluxes of NH4+, NO3−, and labile P in summer using diffusive gradients in thin films technology were 3.4, −37.2, and 0.9 mg m−2 day−1, respectively, based on Fick’s first law. The diffusion flux of labile P was 2.05 mg m−2 day−1 in winter. The contributions fraction of the labile P diffusion flux from sediment to the overlying water were higher in winter than those in summer, because of the relatively lower external input, concentrations and higher diffusion fluxes in winter. After the external input decreased, all of the three diffusion fluxes were lower than the previous record. To understand the influence effect of hydrodynamics, environmental fluid dynamics code modeling was used to simulate the flow and temperature field in winter and summer. Modeling results showed that velocity in summer was higher than that in winter due to concentrated rainfall within the catchment. Moreover, the velocity and temperature in the euphotic zone were higher than that of the hypolimnion in summer. Less variation of velocity and temperature in vertical profile in winter than that in summer was observed, which may be attributable to the high specific heat capacity and the low heat conductivity of water. There was no significant correlation among velocity, hydrochemistry, nitrogen, and phosphorus concentrations. Hydrodynamics, solar radiation, and water depth affect the position of the thermocline, which was consequently to water temperature, hydrochemistry, dissolved nitrogen, and phosphorus concentration. Correlation analysis suggested that the higher bottom velocity and total bed shear may accelerate labile P, NH4+, and NO3− diffusion fluxes. These results provide evidence and suggestions for preventing and controlling reservoir eutrophication and water safety management.

Quantal analysis estimates docking site occupancy determining short-term depression at hippocampal glutamatergic synapses.

Before fusion, synaptic vesicles (SVs) pause at discrete release/docking sites. During repetitive stimulation, the probability of site occupancy changes following SV fusion and replenishment. The occupancy probability is considered to be one of the crucial determinants of synaptic strength, but it is difficult to estimate separately because it usually blends with other synaptic parameters. Thus, the contribution of site occupancy to synaptic function, particularly to synaptic depression, remains elusive. Here, we directly estimated the occupancy probability at the hippocampal mossy fibre-CA3 interneuron synapse showing synaptic depression, using statistics of counts of vesicular events detected by deconvolution. We found that this synapse had a particularly high occupancy (∼0.85) with a high release probability of a docked SV (∼0.8) under 3 mm external calcium conditions. Analyses of quantal amplitudes and SV counts indicated that quantal size reduction decreased the amplitudes of all responses in a train to a similar degree, whereas release/docking site number was unchanged during trains, suggesting that quantal size and release/docking site number had little influence on the extent of synaptic depression. Model simulations revealed that the initial occupancy with high release probability and slow replenishment determined the time course of synaptic depression. Consistently, decreasing external calcium concentration reduced both the occupancy and release probability, and the reductions in turn produced less depression. Based on these results, we suggest that the occupancy probability is a crucial determinant of short-term synaptic depression at glutamatergic synapses in the hippocampus. KEY POINTS: The occupancy probability of a release/docking site by a synaptic vesicle at presynaptic terminals is considered to be one of the crucial determinants of synaptic strength, but it is difficult to estimate separately from other synaptic parameters. Here, we directly estimate the occupancy probability at the hippocampal mossy fibre-interneuron synapse using statistics of vesicular events detected by deconvolution. We show that the synapses have particularly high occupancy (0.85) with high release probability (0.8) under high external calcium concentration ([Ca2+ ]o ) conditions, and that both parameter values change with [Ca2+ ]o , shaping synaptic depression. Analyses of the quantal amplitudes and synaptic vesicle counts suggest that quantal sizes and release/docking site number have little influence on the extent of synaptic depression. The results suggest that the occupancy probability is a crucial determinant of short-term synaptic depression at glutamatergic synapses in the hippocampus.

Estrogen-related receptor γ2 controls NaCl uptake to maintain ionic homeostasis.

Estrogen-related receptors (ERRs) are known to function in mammalian kidney as key regulators of ion transport-related genes; however, a comprehensive understanding of the physiological functions of ERRs in vertebrate body fluid ionic homeostasis is still elusive. Here, we used medaka (Oryzias melastigma), a euryhaline teleost, to investigate how ERRs are involved in ion regulation. After transferring medaka from hypertonic seawater to hypotonic freshwater (FW), the mRNA expression levels of errγ2 were highly upregulated, suggesting that Errγ2 may play a crucial role in ion uptake. In situ hybridization showed that errγ2 was specifically expressed in ionocytes, the cells responsible for Na+/Cl- transport. In normal FW, ERRγ2 morpholino knockdown caused reductions in the mRNA expression of Na+/Cl- cotransporter (Ncc), the number of Ncc ionocytes, Na+/Cl- influxes of ionocytes, and whole-body Na+/Cl- contents. In FW with low Na+ and low Cl-, the expression levels of mRNA for Na+/H+ exchanger 3 (Nhe3) and Ncc were both decreased in Errγ2 morphants. Treating embryos with DY131, an agonist of Errγ, increased the whole-body Na+/Cl- contents and ncc mRNA expression in Errγ2 morphants. As such, medaka Errγ2 may control Na+/Cl- uptake by regulating ncc and/or nhe3 mRNA expression and ionocyte number, and these regulatory actions may be subtly adjusted depending on internal and external ion concentrations. These findings not only provide new insights into the underpinning mechanism of actions of ERRs, but also enhance our understanding of their roles in body fluid ionic homeostasis for adaptation to changing environments during vertebrate evolution.

Simulation of forward osmosis process: Modification of mass transfer coefficient and osmotic pressure equations

The basis of forward osmosis process optimization problems is having a suitable equation for calculating permeate flux. This relationship should provide an accurate prediction of permeate flux by covering all the physical phenomena governing the process, including internal and external concentration polarization. In this work, by applying the computational fluid dynamic method, the effect of two main parameters, Sherwood number and osmotic pressure, on the permeate water flux prediction have been investigated. Mass transfer coefficient performs a decisive role in calculating the concentration polarization. Consequently, seven widely used equations for calculating permeate flux have been investigated. It was found that only a limited number of these equations provided the ability to predict flux accurately. Moreover, using the Adaptive Single-Objective method, a non-linear relationship between osmotic pressure and the salt mass fraction was presented. This relationship can accurately predict the water flux in the broader concentration range of the draw solution.

2,4-D and 2,4-D butoxyethyl ester behavior in Eurasian and hybrid watermilfoil (Myriophyllum spp.).

Hybrid watermilfoil is becoming more prevalent in many lakes where the invasive Eurasian (Myriophyllum spicatum, EWM) and native northern watermilfoil (M. sibiricum) co-occur. These Eurasian and northern watermilfoil hybrids (HWM) grow 30% faster and in many cases are less sensitive to 2,4-dichlorophenoxy acetic acid (2,4-D) than either parent. The mechanism(s) impacting 2,4-D tolerance in these hybrids was investigated by comparing the absorption, translocation, metabolism, and desorption of two 2,4-D formulations in EWM and HWM. 2,4-D absorption in EWM and HWM was 5.7 and 7.9 times the external herbicide concentration determined by the plant concentration factor, a metric used to determine herbicide bioaccumulation, and 2,4-D butoxyethyl ester absorption was 35.6 and 52.1 times the external concentration in EWM and HWM, respectively. Herbicide bioaccumulation was greater in HWM than in EWM. Herbicide translocation to HWM roots was limited at 192 HAT and herbicide desorption in HWM was slightly lower than EWM. No differences were found in herbicide metabolism between the two plant species. 2,4-D resistance in HWM is not due to non-target-site resistance as no differences in herbicide absorption, translocation, desorption and/or metabolism were identified; therefore, target-site resistance is the most likely resistance mechanism. More research is needed to identify the molecular basis for the 2,4-D-resistant trait in HWM. © 2021 Society of Chemical Industry.

Axial forces at disk surfaces in a cylindrical nanopore

Understanding the physics of object translocation in nanopores is critical for using nanopores as sensors of molecular properties and as object size and shape sensors. Based on Poisson-Nernst-Planck and Navier-Stokes simulations we dissect three axial pressures and forces at disk edges (upper, lower and rim) - Coulomb, dielectric and fluidic. Axial Coulomb and dielectric rim forces are small and cancel each other. Upper and lower axial forces are largely controlled by the external axial electric field and interestingly by the pore wall charges that determine the amplitude and direction of axial combined force. Axial total Coulomb force (sum of its upper and lower edge components) makes the greatest contribution, but the axial total dielectric force (calculated using Maxwell stress tensor), which opposes it is surprisingly large. External ion concentration alters Coulomb and axial dielectric forces but influences only their amplitude. Axial total fluidic force is near zero (its upper and lower disk edge components are significant but cancel each other) regardless of external electric field, but pore wall charges and external fluidic pressure can alter it. Modest changes of external electric field or concentration produce axial forces comparable to those produced by large external fluidic pressures. Axial forces depend little on disk's axial position. Finally, mean axial pressures (calculated to compare forces acting on disks of different radius) are greater for larger disks.

Glucose-responsive oral insulin delivery platform for one treatment a day in diabetes

Glucose-responsive oral insulin delivery platform for one treatment a day in diabetes