Thixotropic Properties Research Articles

Formulation and Release of Active Pharmaceutical Ingredients Using a Supramolecular Self-Healing Two-Component Gel.

A two-component low-molecular-weight gelator (LMWG) formed from a modified amino acid and an aldehyde was formulated with active pharmaceutical ingredients (APIs). Basic APIs (propranolol, atropine) can be mixed with the LMWG prior to gel assembly while acidic APIs (naproxen, rosuvastatin) inhibit assembly by disrupting the LMWG imine bond and were loaded by diffusion after gel assembly. For diffusion-loaded gels, the API in the liquid-like phase was rapidly released, with the remainder, interacting with gel fibres, retained in the gel. Rosuvastatin release was particularly low with Saturation Transfer Difference (STD) NMR indicating interactions between the aromatic ring and the self-assembled gel network. Propranolol also interacted with the gel via its aromatic unit, and its release led to gel erosion. Using agarose as a polymer gelator additive reinforced the gel, restricting erosion. In contrast, atropine was readily released over a period of hours - it is primarily in the liquid-like phase with STD NMR indicating no interactions with the gel network. The atropine-loaded gel retained its thixotropic properties. Overall, APIs must be carefully chosen to optimise formulation/release. Of the APIs investigated, atropine has most potential for further development. Atropine has applications in treating myopia, and our results suggest potential ophthalmic applications of supramolecular gels.

General Approach to Hydrolysis Resistive Aluminum Nitride and Its High-Performance Thermal Interface Materials.

Aluminum nitride (AlN), noted for its excellent thermal conductivity and exceptional electrical insulation, presents a promising alternative to traditional ceramic particles in thermal interface materials (TIMs). However, its broader adoption in practical applications is limited by performance degradation due to the vulnerability of its crystal structure to ubiquitous moisture. This study introduces a dual solution, utilizing a mechanochemical method to design a dense outer layer of Galinstan liquid metal (LM) that simultaneously enhances AlN's resistance to hydrolysis and improves its thermal performance in TIM applications. The high surface free energy of the LM layer imparts hydrophobic properties to the AlN surface and, combined with outer metal oxides, forms a dual-layer protective barrier that prevents water penetration, significantly enhancing the TIM's long-term stability in high-humidity conditions. Additionally, the LM layer at the interface improves the thixotropic properties of the TIM and enhances interfacial heat transport through the bridging effect of the LM, resulting in improved rheological mobility and thermal conductivity of the composite material. This win-win surface modification strategy opens opportunities for the practical and durable application of AlN in widespread electronic thermal management.

Fabrication of Zinc(II) Mediated Poly(Acrylamide Co Acrylic Acid) Hydrogel with Thixotropic and Tribological Properties.

Hydrogels have emerged as promising candidates for biomedical applications, such as replacing natural articular cartilage, owing to their unique viscoelastic properties. However, sufficient mechanical properties, self-healing ability, and adhesive nature are some issues limiting its application window. Here, a facile one-pot synthesis of dual cross-linked zinc-coordinated copolymer hydrogels is presented. The network structure of the copolymer hydrogels is strategically developed via dynamic and reversible physical cross-linking by Zn2+ ions and simultaneous covalent cross-linking through a covalent cross-linker viz methylene bisacrylamide. Fourier-transform infrared (FTIR), X-ray diffraction (XRD) scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis have thoroughly characterized the structure of the synthesized hydrogels. The introduction of Zn2+ offers dynamic and reversible complexation, leading to excellent mechanical properties and self-healing features. Moreover, the percentage of the equilibrium water content of zinc-coordinated copolymer hydrogel samples is comparable with that of natural articular cartilage. The Shear sliding study shows the dominant adhesive behavior of HGel-Zn(NO3)2 sample compared to the parent HGel sample. This facile dual cross-linked hydrogel, HGel-Zn(NO3)2, with a combination of good mechanical properties, efficient self-recovery, adequate water content, and favorable adhesive nature, seems very promising to mimic the articular cartilage.

Insight of soy protein isolate to decrease the gel properties corn starch based binary system: Rheological and structural investigation

Dysphagia has become a growing concern for elderly individuals, and starch-based gel foods is expected to become one of the foods easy to swallow. This study investigated the effects of soy protein isolate (SPI) on the sol-gel behavior, rheological, structural and gel properties of corn starch (CS). SPI raised the gelatinization temperature but reduced enthalpy values, inhibiting the gelatinization of CS. There was a reduction of rheological properties in CS-SPI system, involving apparent viscosity, modulus, and shear structural recovery properties, while SPI increased the Tan δ, creep-recovery, and thixotropic properties. Structural analysis demonstrated that SPI introduction altered the lamellar structure, increased the relative crystallinity, and decreased the hydrogen bond strength and order degree in CS-SPI gels, forming a weaker gel network. As a result, the texture profiles such as hardness, gumminess, and chewiness were decreased from 308.60 g to 64.98 g, 285.44 g–50.62 g, and 279.66 g–50.15 g, respectively, whereas the gel strength of CS-SPI gel decreased from 123.91 g to 45.78 g. This study provided foundations for the production of gel food suitable for swallowing.

Using acetic acid as a preconditioner to optimize rheology of alkali-activated coal gasification slag based backfill pastes

The workability of alkali-activated coal gasification slag (CGS) based backfill materials is critical parameter in transportation processes, while the high water demand of CGS hinders its application due to its high specific surface area. This study utilizes acetic acid (AA) as a preconditioner to modify the surface characteristics of CGS, aiming to optimize the rheology of alkali-activated CGS backfill pastes (AAC). The shear stress, viscosity, thixotropic property, and zeta potential of AAC, and mineral composition and surface morphology of AA-modified CGS at various AA dosages were systematically investigated. It is found that the yield stress, plastic viscosity, and hysteresis loop area of AAC reaches the lowest value at 4 wt% AA dosage on the basis of the CGS, owing to AA reacts with the minerals on the surface of CGS particles, and then the AA is adsorbed on the CGS particles and acts as a surfactant, which increases the static electricity between CGS particles. However, the yield stress of AAC increases significantly when the AA dosage exceeds 4 wt%, attributing to the smaller particle size resulting from AA modification, which raises water demand. This investigation proposes a novel approach for optimizing the rheology of CGS based AAC and provides theoretical guidance for employing modified CGS as backfill materials.

Marine sulfated polysaccharide affects the formation mechanism of gelatin emulsion-based oleogels

Protein-polysaccharide delivery systems function as a promising tool to deliver bioactive ingredients aiming to improve their solubility and bioavailability. In this study, gelatin (Gel) and κ-carrageenan (Car) were used to evaluate the characteristics of the Gel-Car emulsion and the emulsion-templated oleogels. Results showed that Car addition significantly reduced the particle size and increased the potential absolute value during emulsion storage, especially for Gel-0.5% Car and Gel-1.0% Car emulsions, indicating Car addition enhanced the emulsion's stability. The emulsions' rheological results indicated that all the emulsions exhibited weak gel-like behavior dominated by elasticity, suggesting Car addition improved the emulsions' shear resistance and viscoelasticity. The emulsions' instability indices were Gel (0.034), Gel-0.1% Car (0.026), Gel-0.5% Car (0.013), and Gel-1.0% Car (0.011), indicating Car addition enhanced the emulsions' stability. For oleogels, Car addition significantly reduced the oil loss rate, delayed the thermal degradation, and improved the viscoelasticity, shear resistance, thixotropic recovery properties, and high-temperature resistance, especially for Gel-1.0% Car oleogel. The stability analysis exhibited that Car addition improved the oleogels' stability, with Gel-0.5% Car oleogel showing the best stability. FFA release was Gel (25.22%), Gel-0.1% Car (26.86%), Gel-0.5% Car (31.38%), and Gel-1.0% Car (39.57%), suggesting Car addition promoted the rapid release of FFA during oleogels digestion. Results above indicated that Gel-Car oleogels exhibited good structural stability and high gel strength, which provide a theoretical basis and new ideas for the preparation of oleogels from protein-marine sulfated polysaccharides using the emulsion template method for food industrial application.

Study on the Rheological and Thixotropic Properties of Fiber-Reinforced Cemented Paste Backfill Containing Blast Furnace Slag

Study on the Rheological and Thixotropic Properties of Fiber-Reinforced Cemented Paste Backfill Containing Blast Furnace Slag

Direct ink writing of customized polymeric structures embedded in a nano-silicate based supporting matrix

The increase in use of intricate structures for engineering applications has encouraged researchers to find new fabrication techniques. This work presents an innovative approach of embedded 3D printing, which allows fabrication of freeform structures by directly 3D printing inside a supporting matrix. The polymer ink solution was prepared by blending polylactic acid (PLA) and polypropylene carbonate (PPC) in 1,4-dioxane. Laponite RD was used to prepare the aqueous nano-silicate suspension, which exhibited yield stress and thixotropic properties due to its house-of-cards arrangement. Solidification of the 3D printed polymer ink occurred due to the hydrogen bonding between the oxygen atoms of dioxane molecules and the protons of water molecules. Particle image velocimetry study showed that the increasing nano-silicate concentration caused a reduction in yield region as a result of increasing yield stress. Dimensionless parameters (Oldroyd number and ratio of yield stress to hydrostatic pressure) for nano-silicate concentrations with values less than 1 were found to facilitate the nozzle movement without crevice formation, while the values greater than 1 were found to be unsuitable for printing. Different intricate structures such as tubular structures with varying geometry that mimic the native trachea, and a bifurcated tube were 3D printed as a proof-of-concept study. The proposed method introduced a novel approach by utilizing the solvent-water interaction capability to fabricate objects with overhanging geometry. This approach allows 3D printing of a wide variety of polymers by leveraging the miscibility between its corresponding solvent and supporting matrix.

ANALYSIS OF THE CHANGE IN THE RHEOLOGICAL CURVE OF THE FLOW OF NON-NEWTONIAN OILS IN THE FIELDS OF WESTERN KAZAKHSTAN

In order to improve oil recovery technologies, the task of studying the rheological properties of oil, which largely determine the development indicators of the development target, namely, the rate of oil withdrawal, the stability and nature of the movement of the front of displacement of oil by water or gas, and, as a result, final oil recovery, is becoming urgent. In this regard, there is a need for in-depth studies of the rheoviscidity properties of produced oils.This article presents the results of laboratory studies to study the rheological characteristics of both high-paraffin and heavy high-viscosity oils using the example of oil from fields in Western Kazakhstan. Since structured oils are thixotropic systems, all experiments were carried out with the same degree of structure destruction in oil, both anhydrous oils and those with different water cuts were studied. The authors also showed the nature of the change in the rheological curve of the flow of oil emulsion of various water cuts to identify the temperature interval where non-Newtonian properties of various oils are manifested. Their main physical and chemical properties are also given, and kinematic viscosities of oil with different densities are compared. The results of laboratory studies of viscosity change with temperature increase for Karazhanbas oil emulsion with different water cut are considered. Despite differences in viscosity values of different degrees of watered samples of highly paraffinic oil, the tendency of oil viscosity change depending on the shear gradient is the same. The formation of structured systems of resin and asphaltene particles is observed in flows with relatively low shear gradients. As a result, oil viscosity dependence on the shear gradient in the range of low values from 0 to 20 s-1 must be taken into account when solving tasks for high-paraffin production. The results obtained are of practical interest, since when creating a compositional model and technological modeling of the collection and transport system, the rheological characteristics of the oil of a particular field, as well as the presence of thixotropic properties, must be taken into account.

Characterization of Langmuir Monolayers for Nanodiamonds Surface‐Modified with 12‐Hydroxystearyl Chains and the Occurrence of Structural Colors

AbstractThe surfaces of nanodiamond particles are modified using natural castor oil‐derived 12‐hydroxystearic acid, which has thixotropic solvent properties. 12‐Hydroxystearyl chain‐modified nanodiamonds (12OHSt‐ND) are spread from a dispersion medium onto ultrapure water to afford Langmuir monolayers (a single‐particle layer) of 12OHSt‐ND exhibited a two‐dimensional phase transition from an expanded phase to a condensed phase. The surface morphology of the single‐particle layer shows a dispersed form of aggregated particles, while the layered regularity of the multilayers shows high periodicity. The surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is more pronounced than that of the single‐particle layer of stearic acid‐modified nanodiamonds. The origin of the surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is predicted to be the vertical conformation of the modified chains achieved via hydrogen bonding between the modified chains. In addition, the stepwise multilayers of 12OHSt‐ND exhibit various structural colors depending on the number of layers.

Differences in fluidity and viscosity of brand-name and generic injectable ointment.

Generic medications contain the identical active ingredient in the same concentration as their branded counterparts and are administered in the same manner, aiming to deliver comparable efficacy, dosage, and clinical outcomes. Nevertheless, variations in additives and formulation processes, particularly noticeable in topical medications, can influence factors like ease of use and patient adherence. Therefore, in this study, we aimed to compare the rheological attributes of branded and generic injectable ointments, assessing disparities in formulation performance and their impact on patient care. Posterisan® Forte and Hemoporison® ointments were used as the branded and generic versions, respectively, and their viscosity, ductility, and viscoelastic properties were evaluated. Posterisan® Forte showcased enhanced spread ability, maintaining uniform flow characteristics across varying temperatures, whereas Hemoporison® displayed pronounced thixotropic properties and stiffness, suggesting potential benefits for applications necessitating reversible viscosity adjustments and heightened rigidity. Despite sharing identical additives, observable differences in physical characteristics highlight the necessity of understanding formulation traits, which could influence ointment behavior. Alterations in fluidity and viscosity may affect how patients perceive and apply the medication, potentially influencing treatment outcomes and the occurrence of adverse effects.

Effect of solid content, particle size, and deflocculant on rheological properties of kaolin suspensions

In this research, two different particle sizes of kaolin were selected, and their rheological properties were characterized by steady-state and dynamic rheological tests. Stress relaxation in the flow curves was a novel finding; redefinition and interpretation of flow curves were the focus of our research. Two methods were used and compared for determining the yield stress. The results showed that suspensions with higher solid content and smaller particle size showed more compact inter-particle interactions, exerting multiple stress relaxation and a strong yield and viscoelastic characteristic. The thixotropic properties were also strongly affected by solid content and particle size, and the differences were reflected in the structural recovery capability. Finally, the effects on rheological properties by introducing deflocculant were studied; the stress relaxation disappeared gradually, and storage modulus and yield stress increased.Moreover, kaolin suspensions with smaller particle sizes required more deflocculant for adsorption and electrical neutralization, confirming that more positively charged edges were exposed after fragmentation. This study has provided an excellent approach to control and adjust the rheological properties of kaolin suspensions in industrial applications.

Obtaining and characterization of natural extracts from mango (Mangifera Indica) peel and its effect on the rheological behavior in new mango kernel starch hydrogels

Hydrogels based on natural polymers have aroused interest from the scientific community. The aim of this investigation was to obtain natural extracts from mango peels and to evaluate their addition (1, 3, and 5%) on the rheological behavior of mango starch hydrogels. The total phenolic content, antioxidant activities, and phenolic acid profile of the natural extracts were evaluated. The viscoelastic and thixotropic behavior of hydrogels with the addition of natural extracts was evaluated. The total phenol content and antioxidant activity of the extracts increased significantly (p<0.05) with the variation of the ethanol-water ratio; the phenolic acid profile showed the contain of p-coumaric, ellagic, ferulic, chlorogenic acids, epicatechein, catechin, querecetin, and mangiferin. The viscoelastic behavior of the hydrogels showed that the storage modulus G′ is larger than the loss modulus G′′ indicating a viscoelastic solid behavior. The addition of extract improved the thermal stability of the hydrogels. 1% of the extracts increase viscoelastic and thixotropic properties, while concentrations of 3 to 5% decreased. The recovery percentage (%Re) decreases at concentrations from 0% to 1% of natural extracts, however, at concentrations from 3% to 5% increased.

Influence of sand layer thickness on the collapse mechanism of tunnels in soil-sand-rock composite strata

Collapse is a severe event during metro tunnel construction, particularly in soil-sand-rock composite strata. Variations in the thickness of sand layers, owing to their high compressibility, flowability, and thixotropic properties, significantly impact the mechanical response and deformation of strata, which also directly determine the stability of tunnel excavation processes. Regarding the complexity of the engineering response of the soil-sand-rock composite strata, a series of model tests were conducted to reveal the collapse mechanism of the metro tunnel in the soil-sand-rock composite strata subjected to varying sand layer thickness in this paper. Meanwhile, the influence of sand thickness on the evolution of collapse form, the response of strata stress, and the variation of the displacement and strain fields were systematically discussed by the monitoring data from the miniature earth pressure cells and a two-dimensional full-field deformation measurement system. Moreover, the collapse evolution process was recorded by the industrial camera. The test results indicated that the horizontal displacement of the tunnel shoulders was more affected by the increase in sand layer thickness than the horizontal displacement of the haunches before the tunnel collapse. The high compressibility of the sand layer resisted the transmission of surcharge load to the rock layer. Once the overlying rock layer above the tunnel vault lost its bearing capacity, the thixotropy and flowability properties of the sand layer caused the collapse face to expand funnel-shaped to both sides. The collapse width of the sand-soil interface was proportional to the sand layer thickness. The greater the sand layer thickness, the weaker the ability to provide stable support for the foot of the temporary stratigraphic arch, further reducing the stability of the temporary stratigraphic arch and leading to a faster collapse rate of the composite strata. In general, the results of this research offer valuable guidance for preventing and controlling tunnel collapse in soil-sand-rock composite strata.

Enhancing thixotropic properties of epoxy resin and mechanical properties of epoxy resin thermosets by polyethyleneimine functionalized carbon nanotubes

Epoxy resin (ER) thermosets are widely applied in various fields due to their high mechanical strength, thermal stability and chemical corrosion resistance. However, the brittleness of ER thermosets and low thixotropic property of ER matrix largely limits their further development. Here, this article develops branched polyethyleneimine (PEI) functionalized carbon nanotube (PEI@CNT) as high-performance nanofiller for simultaneously strengthening and toughening ER thermosets. Benefiting from good dispersity and rich amine groups of PEI@CNT, effective interfacial bonding between PEI@CNT and ER is achieved. The ER thermoset with 0.5 wt% PEI@CNT shows increase in tensile strength by 24.8 % and fracture elongation by 30.0 % compared with pristine ER thermoset. The enhanced mechanical properties of PEI@CNT modified ER thermosets can be ascribed to the chemical interaction between PEI@CNT and ER matrix as well as the formed crack propagation, which can dissipate a lot of fracture energy, further improving the strength and toughness of the ER composites. More importantly, the thixotropic property of ER matrix is largely improved after adding the PEI@CNT filler. This work reports a high-performance nanofiller for enhancing mechanical properties of ER thermosets and processability of ER matrix.

Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide

In recent years, hydrogels have been used as important biomaterials for 3D printing of three dimensional tissues or organs. The key issue for printing a successful scaffold is the selection of a material with a good printability. Rheological properties of hydrogels are believed to pay an important role in 3D printability. However the relations between rheological properties of hydrogels and 3D printability have not been extensively studied. In this study, alginate-based hydrogels were prepared as a model material for an extrusion-based printer and graphene oxide was added to modify the rheological properties and 3D printability of the hydrogels. Rheological studies were performed for the hydrogel samples with different formulas. The range of shear rates that the hydrogels suffered during the printing process was deduced. This range of shear rates helped us to select a proper shear rate to investigate the thixotropic properties of the hydrogels. Furthermore, we also defined some measureable parameters to describe and discuss the quality of 3D printing. The present study shows a new approach to analysis of 3D printability of a hydrogel and also provides some suggestion for 3D printing of 3D scaffolds.

Preparation and Properties of Walnut Protein Isolate-Whey Protein Isolate Nanoparticles Stabilizing High Internal Phase Pickering Emulsions.

To enhance the functional properties of walnut protein isolate (WalPI), hydrophilic whey protein isolate (WPI) was selected to formulate WalPI-WPI nanoparticles (nano-WalPI-WPI) via a pH cycling technique. These nano-WalPI-WPI particles were subsequently employed to stabilize high internal phase Pickering emulsions (HIPEs). By adjusting the mass ratio of WalPI to WPI from 9:1 to 1:1, the resultant nano-WalPI-WPI exhibited sizes ranging from 70.98 to 124.57 nm, with a polydispersity index of less than 0.326. When the mass ratio of WalPI to WPI was 7:3, there were significant enhancements in various functional properties: the solubility, denaturation peak temperature, emulsifying activity index, and emulsifying stability index increased by 6.09 times, 0.54 °C, 318.94 m2/g, and 552.95 min, respectively, and the surface hydrophobicity decreased by 59.23%, compared with that of WalPI nanoparticles (nano-WalPI), with the best overall performance. The nano-WalPI-WPI were held together by hydrophobic interactions, hydrogen bonding, and electrostatic forces, which preserved the intact primary structure and improved resistance to structural changes during the neutralization process. The HIPEs stabilized by nano-WalPI-WPI exhibited an average droplet size of less than 30 μm, with droplets uniformly dispersed and maintaining an intact spherical structure, demonstrating superior storage stability. All HIPEs exhibited pseudoplastic behavior with good thixotropic properties. This study provides a theoretical foundation for enhancing the functional properties of hydrophobic proteins and introduces a novel approach for constructing emulsion systems stabilized by composite proteins as emulsifiers.

Porphyrin Photosensitizers into Polysaccharide-Based Biopolymer Hydrogels for Topical Photodynamic Therapy: Physicochemical and Pharmacotechnical Assessments.

Photodynamic therapy (PDT) is an emerging treatment modality that utilizes light-sensitive compounds, known as photosensitizers, to produce reactive oxygen species (ROS) that can selectively destroy malignant or diseased tissues upon light activation. This study investigates the incorporation of two porphyrin structures, 5-(4-hydroxy-3-methoxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.2.) and 5,10,15,20-tetrakis-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.1.), into hydroxypropyl cellulose (HPC) hydrogels for potential use in topical photodynamic therapy (PDT). The structural and compositional properties of the resulting hydrogels were characterized using advanced techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), UV-Visible (UV-Vis) spectroscopy, and fluorescence spectroscopy. FTIR spectra revealed a slight shift of the main characteristic absorption bands corresponding to the porphyrins and their interactions with the HPC matrix, indicating successful incorporation and potential hydrogen bonding. XRD patterns revealed the presence of crystalline domains within the HPC matrix, indicating partial crystallization of the porphyrins dispersed within the amorphous polymer structure. TGA results indicated enhanced thermal stability of the HPC-porphyrin gels compared to 10% HPC gel, with additional weight loss stages corresponding to the thermal degradation of the porphyrins. Rheological analysis showed that the gels exhibited pseudoplastic behavior and thixotropic properties, with minimal impact on the flow properties of HPC by P2.1., but notable changes in viscosity and shear stress with P2.2. incorporation, indicating structural modifications. AFM imaging revealed a homogeneous distribution of porphyrins, and UV-Vis and fluorescence spectroscopy confirmed the retention of their photophysical properties. Pharmacotechnical evaluations showed that the hydrogels possessed suitable mechanical properties, optimal pH, high swelling ratios, and excellent spreadability, making them ideal for topical application. These findings suggest that the porphyrin-incorporated HPC hydrogels have significant potential as effective therapeutic agents for topical applications.

Development and Optimization of Nasal Composition of a Neuroprotective Agent for Use in Neonatology after Prenatal Hypoxia.

The intranasal route of drug administration is characterized by high bioavailability and is considered promising for rapid delivery of drugs with systemic action to the central nervous system (CNS), bypassing the blood-brain barrier. This is particularly important for the use of neuroprotective drugs in the treatment of brain tissue damage in infants caused by the effects of intrauterine hypoxia. The creation of new dosage forms for neonatology using mathematical technologies and special software in pharmaceutical development allows for the creation of cerebroprotective drugs with controlled pharmaco-technological properties, thus reducing time and resources for necessary research. We developed a new nasal gel formulation with Angiolin using a Box-Behnken experiment design for the therapy of prenatal CNS damage. It was found that the consistency characteristics of the nasal gel were significantly influenced by the gelling agent and mucoadhesive component-sodium salt of carboxymethylcellulose. We optimized the composition of nasal gel formulation with Angiolin using the formed models and relationships between the factors. The optimized nasal gel composition demonstrated satisfactory thixotropic properties. The 1% gel for neuroprotection with Angiolin, developed for intranasal administration, meets all safety requirements for this group of drug forms, showing low toxicity and no local irritant or allergic effects.

Visualization techniques of grease fluidity

Energy-saving technology has become increasingly significant as one of the carbon-neutral options for suppressing recent global warming. Grease-lubricated bearings have been used in various automotive and industrial machinery, requiring low torque and long service life for energy-saving performance, which is greatly influenced by grease fluidity. A numerical approach for understanding grease fluidity is very complex since grease is a non-Newtonian fluid with thixotropic properties. Visualization technique is one of the helpful methods to understand the complex grease fluidity and apply it to practical use. This paper describes state-of-the-art visualization techniques, such as fluorescence method, particle imaging velocimetry, infrared spectroscopy, X-rays, and neutron beams.