Direct Contact Research Articles

Numerical Investigation of Different Cooling Methods for Battery Packs

This paper contains the results of numerical investigations into two cooling system types for cells of three types. The galvanic cell geometries which were considered were pouches, cylinders and prisms. By design, the cooling system for a vehicle is specialised to prevent an uncontrolled temperature increase at higher discharge rates. Consideration was given to the question of which cooling method would be sufficient to reduce the temperature rise of battery cells. The first cooling method investigated is one that uses direct contact with the air flow to cool the cells, a method that is very commonly used in automotive engineering, as it is less complicated. This study employs a method that uses a fan to induce forced convection, increasing the airflow over cells housed within a thermoplastic composite container. Another method, fluid cooling, is notable for its greater efficiency due to the use of a non-conducting coolant, which has also better energy absorption properties. In this study, immersion cooling was employed, utilising oil circulation through cells contained within a thermoplastic composite container, which was facilitated by a pump system. This publication shows the influence of the cell’s geometry and the type of cooling system on the temperature rise of cells when they are discharging at the appropriate power rate. The results of this study highlight the differences in cooling performance between the two methods, providing a clear basis for selecting the most suitable solution for specific applications.

Crosstalk between macrophages and mesenchymal stem cells shape patterns of osteogenesis and immunomodulation in mineralized collagen scaffolds

Mesenchymal stem cells (MSCs) are highly plastic, with the capacity to differentiate into a spectrum of tissue-specific stromal cells. In the field of bone regeneration, MSCs have largely been considered for their osteogenic differentiation capacity. MSCs are increasingly being appreciated for their immunomodulatory potential following exposure to pro-inflammatory stimuli (licensing). Pro-inflammatory environments arise following bone injury via activation of resident immune cells like macrophages. We describe the use of a mineralized collagen scaffold as a bone-mimetic in vitro model to study the influence of paracrine versus direct cell-to-cell contact of THP-1 macrophages on MSC osteogenic and immunomodulatory potential. Paracrine stimuli from macrophages enhance MSC osteogenic and immunomodulatory potential via upregulation of key transcriptomic markers as well as via soluble biomolecule production. Direct co-culture of MSCs and macrophages decreased immunomodulatory potential in MSCs, especially for licensed MSCs, but enhanced matrix remodeling and expression of genes related to macrophage chemotaxis. These data demonstrate the significant effect macrophage-derived paracrine factors and direct contact have on MSC activity in a biomaterial model of bone regeneration. This work illuminates a critical need to further understand these processes in more clinically relevant cell models to inform biomaterial design.

Suitable Method for Improving Friction Performance of Magnetic Wheels with Metal Yokes

A magnetic-wheeled robot is a type of robot that inspects large steel structures instead of humans, and it can run on a three-dimensional path by using wheels with built-in permanent magnets. For the robots to work safely, their magnetic wheels require both magnetic attractive forces and friction forces. Planetary-geared magnetic wheels, which we have developed, make direct contact with their yokes on the running surface to ensure their magnetic attractive force. However, this design decreases their frictional performance more than common magnetic wheels covered with soft materials. Therefore, the yokes require methods that can improve their frictional performance without decreasing their attractive force. To consider the best method for the use of magnetic wheels, this study has run experiments with five types of yokes, which have different processing. As a result, the yokes with corroded surfaces could have maintained the attractive force more than 90% of the time and increased their traction forces by about 36% in static conditions and about 30% in dynamic conditions compared to yokes with no machining. The main reasons for these experimental results are that the rust layer has stable irregularities on the surface and includes ferromagnetic materials.

Connexin 43 regulates intercellular mitochondrial transfer from human mesenchymal stromal cells to chondrocytes

BackgroundThe phenomenon of intercellular mitochondrial transfer from mesenchymal stromal cells (MSCs) has shown promise for improving tissue healing after injury and has potential for treating degenerative diseases like osteoarthritis (OA). Recently MSC to chondrocyte mitochondrial transfer has been documented, but the mechanism of transfer is unknown. Full-length connexin 43 (Cx43, encoded by GJA1) and the truncated, internally translated isoform GJA1-20k have been implicated in mitochondrial transfer between highly oxidative cells, but have not been explored in orthopaedic tissues. Here, our goal was to investigate the role of Cx43 in MSC to chondrocyte mitochondrial transfer. In this study, we tested the hypotheses that (a) mitochondrial transfer from MSCs to chondrocytes is increased when chondrocytes are under oxidative stress and (b) MSC Cx43 expression mediates mitochondrial transfer to chondrocytes.MethodsOxidative stress was induced in immortalized human chondrocytes using tert-Butyl hydroperoxide (t-BHP) and cells were evaluated for mitochondrial membrane depolarization and reactive oxygen species (ROS) production. Human bone-marrow derived MSCs were transduced for mitochondrial fluorescence using lentiviral vectors. MSC Cx43 expression was knocked down using siRNA or overexpressed (GJA1 + and GJA1-20k+) using lentiviral transduction. Chondrocytes and MSCs were co-cultured for 24 h in direct contact or separated using transwells. Mitochondrial transfer was quantified using flow cytometry. Co-cultures were fixed and stained for actin and Cx43 to visualize cell-cell interactions during transfer.ResultsMitochondrial transfer was significantly higher in t-BHP-stressed chondrocytes. Contact co-cultures had significantly higher mitochondrial transfer compared to transwell co-cultures. Confocal images showed direct cell contacts between MSCs and chondrocytes where Cx43 staining was enriched at the terminal ends of actin cellular extensions containing mitochondria in MSCs. MSC Cx43 expression was associated with the magnitude of mitochondrial transfer to chondrocytes; knocking down Cx43 significantly decreased transfer while Cx43 overexpression significantly increased transfer. Interestingly, GJA1-20k expression was highly correlated with incidence of mitochondrial transfer from MSCs to chondrocytes.ConclusionsOverexpression of GJA1-20k in MSCs increases mitochondrial transfer to chondrocytes, highlighting GJA1-20k as a potential target for promoting mitochondrial transfer from MSCs as a regenerative therapy for cartilage tissue repair in OA.

A Novel Wearable Sensor for Measuring Respiration Continuously and in Real Time.

In this work, a flexible textile-based capacitive respiratory sensor, based on a capacitive sensor structure, that does not require direct skin contact is designed, optimised, and evaluated using both computational modelling and empirical measurements. In the computational study, the geometry of the sensor was examined. This analysis involved observing the capacitance and frequency variations using a cylindrical model that mimicked the human body. Four designs were selected which were then manufactured by screen printing multiple functional layers on top of a polyester/cotton fabric. The printed sensors were characterised to detect the performance against phantoms and impacts from artefacts, normally present whilst wearing the device. A sensor that has an electrode ratio of 1:3:1 (sensor, reflector, and ground) was shown to be the most sensitive design, as it exhibits the highest sensitivity of 6.2% frequency change when exposed to phantoms. To ensure the replicability of the sensors, several batches of identical sensors were developed and tested using the same physical parameters, which resulted in the same percentage frequency change. The sensor was further tested on volunteers, showing that the sensor measures respiration with 98.68% accuracy compared to manual breath counting.

Preparation of core-shell Si/C/graphene composite for high-performance lithium-ion battery anodes

One of the important objectives for the development of enhanced lithium-ion batteries is developing high-performance silicon-based anodes with durable operational capability. Herein, a three-dimensional graphene-decorated core-shell Si/C composite is fabricated by the in-situ polymerization of organic pyrrole molecule and pyrolysis process, in which the melamine formaldehyde resin is subtly used as three-dimensional porous framework to offer abundant loading area for the uniform dispersion of active silicon nanoparticles. Meanwhile, the core-shell structure deriving from polypyrrole in the composite can effectively buffer the volume change of silicon ingredient and avoid the direct contact with the electrolyte during the cycling process, leading to the improved structural stability and electrochemical performance. The outermost layer of graphene nanosheets is designed to enhance the electrical conductivity of the electrode. As a result, the synthesized Si/C/graphene composite exhibits a high capacity and excellent cycling performance. This work reveals that combining a three-dimensional carbon substrate with a core-shell structure might be a promising solution for anode materials with obvious volume transformation.

A bottom-up framework to investigate environmental and techno-economic aspects of lithium-ion batteries: A case study of conventional vs. pre-lithiated lithium-ion battery cells

As per-lithiation emerges as a promising technology for the next generation of lithium-ion battery cells, aimed at enhancing energy density and cycle life, it is crucial to evaluate its technological, production cost, and environmental impacts on an industrial scale. In this study, we developed a cradle-to-gate process-based model framework using LiNi0.8Mn0.1Co0.1O2 (NMC811)/Graphite as a reference cell to propose industrial-scale roll-to-roll direct contact pre-lithiation method for NMC811/Prelithiated-Graphite (prGr) and NMC811/Prelithiated-Graphite-Silicon (prGrSi) cells. Our findings indicate that pre-lithiated cells exhibit a gravimetric energy density increase of approximately 11%–27% compared to the baseline of 288 Wh.kg−1. This improvement could offset or even reduce the environmental impacts associated with the additional lithium foil component inserted into the cell during production. Economically, our analysis underscores the significant influence of lithium foil unit price, which is a critical factor in the overall cost of this technology, and a stable material market is crucial for its success. Overall, the investigation into environmental and economic aspects suggests that the prospects for industrialization and adoption are more promising than challenging in the near term.

Novel post-heat treatment green biodegradable PLA@SiO2 nanocomposite membrane for water desalination

Membrane distillation (MD) has received significant attention because of its energy efficiency and ability to treat industrial wastewater and salty water. However, the synthetic nature of commonly used membranes raises environmental disposal concerns, requiring the development of alternative eco-membranes. To address this issue, a novel, eco-friendly membrane using polylactic acid (PLA) coated with green silica nanoparticles (SiO2 NPs), modified by post-heat treatment, was developed for effective direct contact membrane distillation (DCMD). Herein, two nanofibrous membranes were fabricated via electrospinning/electrospraying: one, PLA, with a 12.5 wt% PLA solution, and another, PLA@SiO2, with 2 % (w/v) SiO2 NPs coating. The PLA@SiO2 membrane demonstrated enhanced hydrophobicity. Various post-heat treatments were applied to optimize membrane properties, such as structure, pore size, hydrophobicity, liquid entry pressure (LEP), thickness, and thermal stability. In addition, the desalination performance of all membranes was evaluated using a DCMD unit for 6 h. Results showed that the heat-pressed then annealed PLA@SiO2 membrane (denoted M44) exhibited notable improvements, including an LEP of 128.7 kPa, a tunable pore size of 0.21 μm, and a contact angle of 135.9°. Furthermore, the M44 membrane demonstrated a porosity of 80.5 %, a stable permeate flux of 14.3 kg.m−2.h−1, and an exceptional salt rejection of 99.99 % over a 24 h DCMD test. This novel eco-membrane shows promising potential for efficient desalination and represents a significant advancement in sustainable MD applications.

In‐Situ Constructing a Mixed‐Conductive Interfacial Protective Layer for Ultra‐Stable Lithium Metal Anodes

Lithium metal batteries are the most promising next‐generation energy storage technologies due to their high energy density. However, their practical application is impeded by serious interfacial side reactions and uncontrolled dendrite growth of lithium metal anode. Herein, copper 2,4,5‐trifluorophenylacetate is designed and explored to stabilize lithium metal anode by in‐situ constructing a dense and mixed‐conductive interfacial protective layer. The formed passivated layer not only significantly inhibits interfacial side reactions by avoiding direct contact between lithium metal anode and electrolyte but also effectively suppresses lithium dendrite growth due to the unique inorganic‐rich compositions and mixed‐conductive properties. As a result, the copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes show greatly improved cycle stability under both high current density and high areal deposition capacity. Notably, the assembled liquid symmetrical cells with copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes can stably work for more than 3000, 5000, and 4800 h at 1.0 mA cm−2–1.0 mAh cm−2, 2.0 mA cm−2–5.0 mAh cm−2, and 10 mA cm−2–5.0 mAh cm−2, respectively. Furthermore, the assembled liquid full cell with a high LiFePO4 loading (~16.9 mg cm−2) shows a significantly enhanced cycle life of 250 cycles with stable Coulombic efficiencies (>99.1%). Moreover, the assembled all‐solid‐state lithium metal battery with a high LiNi0.6Co0.2Mn0.2O2 loading (~5.0 mg cm−2) also exhibits improved cycle stability. These findings underline that the copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes show great promise for high‐performance lithium metal batteries.

Bio-inspired chemistry for developing micro/nano structured nanofiber membranes for membrane distillation

Membrane distillation (MD) holds significant promise for effluent purification to mitigate the global water shortage. However, the existing petroleum-based MD membranes suffer from high costs, limited sustainability, and wetting issues. Herein, we employed biosynthetic bacterial cellulose (BC) as the substrate and successfully achieved a uniform and stable dispersion of ZnO nanoflowers onto the BC nanofibers through in-situ synthesis technology. After undergoing a fluorination process, a superhydrophobic membrane was prepared by the synergistic effect of micro/nano structures and low surface energy. The resulting membrane exhibited exceptional properties, including a remarkable contact angle of 151.7°, a substantial liquid entry pressure of 2.5 bar, and exhibiting structural integrity and high hydrophobicity even under harsh conditions. Furthermore, this strategy ensured exceptional membrane porosity (∼94.9 %), increased the permeation flux and reduced conductive heat transfer, thereby enhancing the thermal efficiency of the membrane. Furthermore, the membrane demonstrated effective bactericidal activity and self-cleaning capability, facilitating easy cleaning and extending service life. These properties endow the membrane with an impressive durability. After 96 h of continuous operation, the membrane maintained a stable permeation flux of 10.29 L m−2 h−1 and an extraordinary salt rejection rate exceeding 99.9 %. Notably, even with the addition of sodium dodecyl sulfate to the feed, the membrane exhibited stable permeation flux and outstanding antiwetting properties. In summary, the MD membrane fabricated using the bio-inspired chemistry demonstrated a promising potential for long-term applications in direct contact MD operations.

Investigating the expansion behavior of silicon nitride nanopores

Nanopores are a single-molecule detection platform that has attracted more and more researchers’ attention, but so far there is still a lack of systematic research on their stability. In this study, we investigated the mechanism behind the expansion behavior of solid-state nanopores and its effect on the electrical properties of nanopores. Through the analysis of electron energy loss spectroscopy, it was found that the expansion process of nanopores is accompanied by the loss of silicon elements. Three nanopore expansion models can well explain the differential impact of silicon element loss in different regions on the electrical properties of nanopores. Molecular dynamics simulations analyzed the differences in nanopore conductivity and expansion rate corresponding to different expansion models from the perspective of single-atom loss. Finally, we demonstrated that chemical modification can isolate direct contact between the nanopore wall and the solution, thereby greatly delaying the expansion behavior of solid-state nanopores.

Construction of Z‐type heterojunction Bi4Ti3O12/g‐C3N4 with pyroelectric effect for enhanced photocatalytic performance

AbstractPhotocatalytic technology has been widely studied, discussed, and tested as a feasible wastewater degradation technology. The present study demonstrated the preparation of g‐C3N4 material using solid‐state sintering method and the construction of Bi4Ti3O12/g‐C3N4 heterostructure via hydrothermal method. This direct contact Z‐type heterojunction improves the wide bandgap of Bi4Ti3O12 monomer, enhances its photoresponsiveness, and thus improves its photocatalytic performance. During the process of photocatalytic experiments, an environment of cold and hot fluctuations were created, and the pyroelectric effect was utilized to induce self‐polarization of the material and formed an internal electric field. It improves the transport ability of electron–hole pairs and suppresses their recombination in the transport path. According to the degradation experiment results, the degradation efficiency of pyroelectric synergistic heterojunction photocatalysis reached 88.7%, which was 2.27 times that of Bi4Ti3O12. It proves that the photocatalysis by pyroelectric synergistic heterojunction has good application prospects.

Micro-Nanoparticle Characterization: Establishing Underpinnings for Proper Identification and Nanotechnology-Enabled Remediation.

Microplastics (MPLs) and nanoplastics (NPLs) are smaller particles derived from larger plastic material, polymerization, or refuse. In context to environmental health, they are separated into the industrially-created "primary" category or the degradation derivative "secondary" category where the particles exhibit different physiochemical characteristics that attenuate their toxicities. However, some particle types are more well documented in terms of their fate in the environment and potential toxicological effects (secondary) versus their industrial fabrication and chemical characterization (primary). Fourier Transform Infrared Spectroscopy (FTIR/µ-FTIR), Raman/µ-Raman, Proton Nuclear Magnetic Resonance (H-NMR), Curie Point-Gas Chromatography-Mass Spectrometry (CP-gc-MS), Induced Coupled Plasma-Mass Spectrometry (ICP-MS), Nanoparticle Tracking Analysis (NTA), Field Flow Fractionation-Multiple Angle Light Scattering (FFF-MALS), Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), Differential Mobility Particle [Sizing] (DMPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Scanning Transmission X-ray Microspectroscopy (STXM) are reviewed as part of a suite of characterization methods for physiochemical ascertainment and distinguishment. In addition, Optical-Photothermal Infrared Microspectroscopy (O-PTIR), Z-Stack Confocal Microscopy, Mueller Matrix Polarimetry, and Digital Holography (DH) are touched upon as a suite of cutting-edge modes of characterization. Organizations, like the water treatment or waste management industry, and those in groups that bring awareness to this issue, which are in direct contact with the hydrosphere, can utilize these techniques in order to sense and remediate this plastic polymer pollution. The primary goal of this review paper is to highlight the extent of plastic pollution in the environment as well as introduce its effect on the biodiversity of the planet while underscoring current characterization techniques in this field of research. The secondary goal involves illustrating current and theoretical avenues in which future research needs to address and optimize MPL/NPL remediation, utilizing nanotechnology, before this sleeping giant of a problem awakens.

A Copper-Based Coating for the Control of Airborne Viable Bacteria in a Prison Environment

Infections in confined environments can spread by direct contact, contaminated surfaces, and airborne transmission. This is critical in prison facilities, where cleaning and sanitary conditions are inadequate. An alternative is the development of antimicrobial surfaces. A new antimicrobial coating was developed by incorporating copper microparticles into a standard commercial paint, aiming to reduce the concentration of bacteria on surfaces by granting antimicrobial properties to surfaces. The copper additive comprised Cu2Cl(OH)3 deposited on polyhedral zeolite. The efficacy of this coating was evaluated in detention cells in a police station, which are temporary prisons and inherently dirty environments. The experiment compared a cell painted with the copper additive coating and a control cell with the standard paint. Viable coliforms were measured on different surfaces and in the air for five months under normal usage. Bacterial load was reduced by ca. 68% by the copper-amended paint on cement surfaces. Surprisingly, airborne viable coliforms were reduced by ca. 87% in the detention cell treated with the copper coating. This research highlights the potential of antimicrobial coatings in controlling the spread of infections through contact with contaminated surfaces and emphasizes the significant reduction in airborne bacterial load. It is especially relevant for controlling infections where sanitization is limited but can be extended to other built environments, such as healthcare facilities.

Germanium doped D-shaped PCF-SPR methane high sensitivity sensor

Abstract A D-shaped photonic crystal fiber doped with germanium dioxide methane gas sensor based on SPR effect is proposed. The substrate of the fiber is silicon dioxide doped with germanium dioxide, and the polished surface is used as a substrate for gold-plated and methane-sensitive membranes where the sensing area is in direct contact with methane gas. Effects of different germanium dioxide doping concentrations and the structural parameters of the photonic crystal fiber on the performance of the sensor are numerically investigated by the finite element method. Simulation results show that when the germanium dioxide doping concentration is 4.1%, the maximum sensitivity of sensor is 82 nm/% with a maximum resolution of 1.2195 × 10–4 in the range of 0 ∼ 3.5% methane concentration. The proposed sensor not only has a simple structure, but also exhibits high sensitivity, thus the sensor has great potential in pre-warning and remote monitoring of methane gas leakage.

Oxidative Stress, Glutaredoxins, and Their Therapeutic Potential in Posterior Capsular Opacification.

Posterior capsular opacification (PCO) is the most common long-term complication of cataract surgery. Traditionally, the pathogenesis of PCO involves the residual lens epithelial cells (LECs), which undergo transdifferentiation into a myofibroblast phenotype, hyperproliferation, matrix contraction, and matrix deposition. This process is driven by the marked upregulation of inflammatory and growth factors post-surgery. Recently, research on the role of redox environments has gained considerable attention. LECs, which are in direct contact with the aqueous humour after cataract surgery, are subjected to oxidative stress due to decreased levels of reduced glutathione and increased oxygen content compared to contact with the outer fibre layer of the lens before surgery. In this review, we examine the critical role of oxidative stress in PCO formation. We also focus on glutaredoxins (Grxs), which are antioxidative enzymes produced via deglutathionylation, their protective role against PCO formation, and their therapeutic potential. Furthermore, we discuss the latest advancements in PCO therapy, particularly the development of advanced antioxidative pharmacological agents, and emphasise the importance and approaches of anti-inflammatory and antioxidant treatments in PCO management. In conclusion, this review highlights the significant roles of oxidative stress in PCO, the protective effects of Grxs against PCO formation, and the potential of anti-inflammatory and antioxidant therapies in treating PCO.

Dual-functionalized architecture enables stable and tumor cell-specific SiO2NPs in complex biological fluids.

Most commercial anticancer nanomedicines are administered intravenously. This route is fast and precise as the drug enters directly into the systemic circulation, without undergoing absorption processes. When nanoparticles come into direct contact with the blood, however, they interact with physiological components that can induce colloidal destabilization and/or changes in their original biochemical identity, compromising their ability to selectively accumulate at target sites. In this way, these systems usually lack active targeting, offering limited therapeutic effectiveness. In the literature, there is a paucity of in-depth studies in complex environments to evaluate nanoparticle stability, protein corona formation, hemolytic activity, and targeting capabilities. To address this issue, fluorescent silica nanoparticles (SiO2NPs) are here functionalized with zwitterionic (kinetic stabilizer) and folate groups (targeting agent) to provide selective interaction with tumor cell lines in biological media. The stability of these dually functionalized SiO2NPs is preserved in unprocessed human plasma while yielding a decrease in the number of adsorbed proteins. Experiments in murine blood further proved that these nanoparticles are not hemolytic. Remarkably, the functionalized SiO2NPs are more internalized by tumor cells than their healthy counterparts. Investigations of this nature play a crucial role in garnering results with greater reliability, allowing the development of nanoparticle-based pharmaceutical drugs that exhibit heightened efficacy and reduced toxicity for medical purposes.

Investigating the Effects of Induction Heating on a Submerged Hollow Cylindrical Element

ABSTRACTThis article proposes an induction heating element that addresses heat transfer and thermal homogenization while being fully submerged in a liquid, specifically focusing on heating of water as a case study. The design calculations, fabrication, and realization of a resonant induction heating system that heats the proposed heating element are presented. The geometric shape of proposed heating element is a hollow cylinder that maintains structural strength while delivering required thermal energy because of an external time‐varying magnetic field. Detailed mathematical modeling of the proposed heating element's equivalent electric circuit has been presented while considering physical parameters including diameter, thickness, height, material properties, magnetic field frequency, and skin effect. A laboratory scale prototype of the induction heating system including the proposed heating element has been built, and experiments have been demonstrated. The experimental results of the working induction heating resonant inverter and RLC resonant circuit inductance and capacitance with induction load are presented. Additionally, the results of thermographic images and temperature–time profile of the water sample, which was heated using the proposed heating element, are provided to demonstrate the heating element's reliability and practicality. This research contributes to the field of induction heating technology by investigating a heating element that is submerged in a liquid medium, resulting in a uniform temperature distribution throughout the liquid. The conventional method of heating water in a stainless steel cup‐shaped container is an inefficient heat transfer process. In stainless steel cup‐shaped containers, a portion of the energy input used to boil the water is lost to the environment through the surface area of the container that is not in direct contact with the water. This heat loss occurs due to the container's design, which exposes a large surface area to the surrounding environment, allowing thermal energy to dissipate through conduction, convection, and radiation.

Symmetry breaking and fate divergence during lateral inhibition in Drosophila.

Lateral inhibition mediates alternative cell fate decision and produces regular cell fate patterns with fate symmetry breaking (SB) relying on the amplification of small stochastic differences in Notch activity via an intercellular negative feedback loop. Here, we used quantitative live imaging of endogenous Scute (Sc), a proneural factor, and of a Notch activity reporter to study the emergence of Sensory Organ Precursor cells (SOPs) in the pupal abdomen of Drosophila. SB was observed at low Sc levels and was not preceded by a phase of intermediate Sc expression and Notch activity. Thus, mutual inhibition may only be transient in this context. In support of the intercellular feedback loop model, cell-to-cell variations in Sc levels promoted fate divergence. The size of the apical area of competing cells did not detectably bias this fate choice. Surprisingly, cells that were in direct contact at the time of SB could adopt the SOP fate, albeit at low frequency (10%). These lateral inhibition defects were corrected by cellular rearrangements, not cell fate change, highlighting the role of cell-cell intercalation in pattern refinement.

Bernstein operational matrix of differentiation to analyze the conductive, convective, and radiative non-linear sublimation model with temperature-dependent internal heat generation

Theoretical modeling of solid-vapor phase change process, known as sublimation, is of much interest in the pharmaceutical industry and freeze-drying technology. While past theoretical studies on sublimation assume that the phase change material (PCM) remains in direct contact with the heat source or sink with no heat loss due to the surrounding temperature, in most practical scenarios, PCM experiences less heat on its surface due to the loss of some amount of heat in the surrounding environment. Considering the impact of heat radiation on the porous surface is essential for ensuring the precision of the phase change process. The present study reports a theoretical model of a sublimation problem where heat generation is in proportion to the local temperature and loss of heat due to thermal radiation occurs in the porous medium. In connection with thermal radiation, a convective boundary condition is assumed at the surface of the porous body. The solution of the non-linear mathematical model is determined numerically via the Bernstein operational matrix of differentiation method. It is found that temperature-dependent heat generation enhances the temperature within the porous medium and thus, the rate of sublimation increases, while it is delayed due to heat loss through the radiation.