Amorphous Research Articles

Caseous Calcification of the Mitral Annulus: Calcified Toothpaste of the Heart.

Caseous calcification of the mitral annulus (CCMA) is a rare variant of mitral annular calcification (MAC) usually described as an antemortem finding. We report a case of sudden cardiac arrest in a 39-year-old male with end-stage renal disease undergoing hemodialysis with a history of Fabry disease by kidney biopsy. Autopsy revealed significant circumferential annular calcification in both mitral and aortic valves with a caseous gross appearance. Histologically, these areas consisted of amorphous basophilic material accompanied by a surrounding granulomatous-appearing infiltrate. Von Kossa staining on non-decalcified tissue revealed strong positive staining, confirming CCMA diagnosis. While identifiable, the atrioventricular node was displaced and distorted by caseous deposits. Toluidine blue staining of myocardium showed osmophilic accumulations, and electron microscopy (EM) showed myeloid/zebra bodies, consistent with Fabry disease. We posit that Fabry disease leads to end-stage kidney disease, altering calcium phosphate metabolism, a proposed mechanism for CCMA. This case highlights the multifactorial nature of sudden cardiac death in decedents with various structural cardiac changes and potential renal-disease-induced electrolyte imbalances. We aim to bring awareness to this rare entity, its potential role in a sudden cardiac death, and to highlight the need to use non-decalcified tissue when staining for calcium to establish the diagnosis.

Effect of Aerosol Size on Glass Transition Temperature.

The amorphous phase state of suspended nanoparticles affects their atmospheric lifetimes and environmental impact. Influence of relative humidity and chemical composition on the glass-to-liquid transition is well-known. However, the influence of the particle size on the phase transition remains uncertain. Here we show experimental data that probe the amorphous phase transition of suspended sucrose particles as a function of particle size. The depression in glass-transition temperature follows the Gibbs-Thomson or Keesom-Laplace predicted proportionality of ΔTg ∝ D-1 for particles 100-700 nm in diameter, but the proportionality changes to ΔTg ∝ D-1/2 for smaller sizes. Literature data for glass-transition temperature depression in thin films and nanoconfined compounds show similar and strong deviations from the expected D-1 behavior. While the observed proportionalities remain incompletely understood, the results here provide evidence that the deviation from ΔTg ∝ D-1 is not attributable to substrate effects.

Femtosecond nonlinear optical properties of Ti-doped In2Te3 thin films grown by magnetron co-sputtering

Herein, we successfully prepared Ti-doped In2Te3 and pure In2Te3 films by magnetron co-sputtering at room temperature. The film structure was measured using x-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS), while the linear optical constant of the films was measured using a spectroscopic ellipsometer (SE). The nonlinear optical properties of the films were examined using the Z-scan technique, wherein the samples were irradiated with 140 fs laser pulses at a wavelength of 800 nm and a repetition rate of 80 MHz, with an input intensity of 1.2GW/cm2. Ti incorporation led to decreased crystallinity and a reduction (redshift) in the optical bandgap (E g ). All films exhibit reverse saturation absorption (RSA) and self-focusing effect. A ninefold increase in the nonlinear refractive index (n2) and a fourfold increase in the nonlinear absorption coefficient (β) were observed for the Ti-doped S40 sample in comparison to the pure S0 sample. Adjusting the phase transition between amorphous and crystalline states in Ti-doped In2Te3 films further modulated their nonlinear optical properties. The optical limiting (OL) behavior of pure In2Te3 and Ti-doped In2Te3 thin films was investigated, and the results demonstrated that Ti-doped In2Te3 films show great promise as optical limiter devices in nonlinear photonics.

Microwave-assisted fabrication of nanostructured borate bioactive glass and its bioactivity.

Sol-gel bioactive glass with nanocrystalline structures has demonstrated enhanced bioactivity and acceptance by the surrounding bone tissue. In particular, borate bioactive glasses exhibit higher reactivity and apatite formation under the simulated in vitro and in vivo conditions. This study presents a microwave-assisted synthesis of borate bioactive glass (58S) and an understanding of its structural and in vitro bioactivity. By this synthesis method, the nanocrystalline structures formed within the amorphous matrix will regulate the degradation rate of the glass network during apatite formation. The calcinated borate bioactive glass features a nanorod crystalline hydroxyapatite structure embedded in the amorphous borate glass network. The formation of apatite on the surface of borate bioactive glass within 6 hours of immersion in simulated body fluid confirms the material's enhanced bioactivity and reactivity. Anti-oxidant studies, cell viability, and alkaline phosphate activity further corroborate the bioactivity of borate bioactive glass. In summary, this study highlights the significant potential of microwave-synthesized borate bioactive glass for a wide range of bone tissue engineering applications.

Volcanic Eruption in the Nanoworld: Efficient Oxygen Exchange at the Si/SnO2 Interface.

Here, a phenomenon of efficient oxygen exchange between a silicon surface and a thin layer of tin dioxide during chemical vapor deposition is presented, which leads to a unique Sn:SiO2 layer. Under thermodynamic conditions in the temperature range of 725-735°C, the formation of nanostructures with volcano-like shapes in "active" and "dormant" states are observed. Extensive characterization techniques, such as electron microscopy, X-ray diffraction, synchrotron radiation-based X-ray photoelectron, and X-ray absorption near-edge structure spectroscopy, are applied to study the formation. The mechanism is related to the oxygen retraction between tin(IV) oxide and silicon surface, leading to the thermodynamically unstable tin(II)oxide, which is immediately disproportionate to metallic Sn and SnO2 localized in the SiO2 matrix. The diffusion of metallic tin in the amorphous silicon oxide matrix leads to larger agglomerates of nanoparticles, which is similar to the formation of a magma chamber during the natural volcanic processes followed by magma eruption, which here is associated with the formation of depressions on the surface filled with metallic tin particles. This new effect contributes a new approach to the formation of functional composites but also inspires the development of unique Sn:SiO2 nanostructures for diverse application scenarios, such as thermal energy storage.

Robust Electrothermal Switching of Optical Phase‐Change Materials through Computer‐Aided Adaptive Pulse Optimization

Electrically tunable optical devices present diverse functionalities for manipulating electromagnetic waves by leveraging elements capable of reversibly switching between different optical states. This adaptability in adjusting their responses to electromagnetic waves after fabrication is crucial for developing more efficient and compact optical systems for a broad range of applications, including sensing, imaging, telecommunications, and data storage. Chalcogenide‐based phase‐change materials (PCMs) have shown great promise due to their stable, nonvolatile phase transition between amorphous and crystalline states. Nonetheless, optimizing the switching parameters of PCM devices and maintaining their stable operation over thousands of cycles with minimal variation can be challenging. Herein, the critical role of PCM pattern as well as electrical pulse form in achieving reliable and stable switching is reported on, extending the operational lifetime of the device beyond 13000 switching events. To achieve this, a computer‐aided algorithm that monitors optical changes in the device and adjusts the applied voltage in accordance with the phase transformation process is developed, thereby significantly enhancing the lifetime of these reconfigurable devices. The findings reveal that patterned PCM structures show significantly higher endurance compared to blanket PCM thin films.

Evidence of intrinsic structural heterogeneity by monatomic metallic glass

Structural heterogeneity is generally considered to be an intrinsic feature of metallic glasses (MGs), playing a crucial role in their numerous exceptional properties. Prior studies on the structural and dynamic heterogeneities of MGs mainly focused on multi-element systems, which were possibly caused by chemical variations, challenging to exclude. This study employed a monatomic MG, as an ideal system, to investigate structural heterogeneities despite chemical factors using atomic force microscopy. Our results confirm the persistence of markedly structural heterogeneities in monatomic MGs, which cannot be entirely eliminated through annealing, thereby solidifying the intrinsic nature of structural heterogeneity in amorphous solids. Furthermore, we discover that tuning heterogeneity allows for tailoring the properties of monatomic MGs. This work provides conclusive evidence of the intrinsic property of heterogeneity in amorphous solids, reveals the hidden the complexity which covered by the chemical factors, and could advance the current understanding of the nature of glasses.

Design of Experiments-Driven Optimization of Spray Drying for Amorphous Clotrimazole Nanosuspension.

This study employed a Quality by Design (QbD) approach to spray dry amorphousclotrimazole nanosuspension (CLT-NS) consisting of Soluplus® and microcrystallinecellulose. Using the Box-Behnken Design, a systematic evaluation was conducted toanalyze the impact of inlet temperature, % aspiration, and feed rate on the criticalquality attributes (CQAs) of the clotrimazole spray-dried nanosuspension (CLT-SDNS). In this study, regression analysis and ANOVA were employed to detect significantfactors and interactions, enabling the development of a predictive model for the spraydrying process. Following optimization, the CLT-SD-NS underwent analysis using Xraypowder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), Dynamic Scanning Calorimetry (DSC), and in vitro dissolution studies. The resultsshowed significant variables, including inlet temperature, feed rate, and aspiration rate,affecting yield, redispersibility index (RDI), and moisture content of the final product. The models created for critical quality attributes (CQAs) showed statistical significanceat a p-value of 0.05. XRPD and DSC confirmed the amorphous state of CLT in theCLT-SD-NS, and FTIR indicated no interactions between CLT and excipients. In vitrodissolution studies showed improved dissolution rates for the CLT-SD-NS (3.12-foldincrease in DI water and 5.88-fold increase at pH 7.2 dissolution media), attributed torapidly redispersing nanosized amorphous CLT particles. The well-designed studyutilizing the Design of Experiments (DoE) methodology.

An Artificial Intelligence Constitutive Model for Amorphous Solids Utilizing Graph Neural Networks

An Artificial Intelligence Constitutive Model for Amorphous Solids Utilizing Graph Neural Networks

Karanjin-loaded soya lecithin-based ethosomal nanogel for the therapeutic intervention of psoriasis: formulation development, factorial design based-optimization, in vitro and in vivo assessment

This study aimed to develop and optimize karanjin-loaded ethosomal nanogel formulation and evaluate its efficacy in alleviating symptoms of psoriasis in an animal model induced by imiquimod. These karanjin-loaded ethosomal nanogel, were formulated to enhance drug penetration into the skin and its epidermal retention. Karanjin was taken to formulate ethosomes due to its potential ani-psoriatic activity. Ethosomes were formulated using the cold method using 32 full factorial designs to optimize the formulation components. 9 batches were prepared using two independent variables X 1: concentration of ethanol and X 2: concentration of phospholipid whereas vesicle size (Y 1) and percentage entrapment efficiency (Y 2) were selected as dependent variables. All the dependent variables were found to be statistically significant. The optimized ethosomal suspension (B3) exhibited a vesicle size of 334 ± 2.89 nm with an entrapment efficiency of 94.88 ± 1.24% and showed good stability. The morphology of vesicles appeared spherical with smooth surfaces through transmission electron microscopy analysis. X-ray diffraction analysis confirmed that the drug existed in an amorphous state within the ethosomal formulation. The optimized ethosome was incorporated into carbopol 934 to develop nanogel for easy application on the skin. The nanogel underwent characterization for various parameters including spreadability, viscosity, pH, extrudability, and percentage drug content. The ethosomal formulation remarkably enhanced the skin permeation of karanjin and increased epidermal retention of the drug in psoriatic skin compared to marketed preparation and pure drug. A skin retention study showed that ethosomal nanogel formulation has 48.33% epidermal retention in 6 h. In vivo, the anti-psoriatic activity of karanjin ethosomal nanogel demonstrated significant improvement in psoriasis, indicated by a gradual decrease in skin thickness and scaling as reflected in the Psoriasis Severity Index grading. Therefore, the prepared ethosomal nanogel is a potential vehicle for improved topical delivery of karanjin for better treatment of psoriasis.

Long-term ablation behavior of Al4SiC4-YB4 modified Cf/ZrB2-SiC composites at 2600 °C

Long-term ablation behavior of Al4SiC4-YB4 modified Cf/ZrB2-SiC composites was characterized by air plasma torch at 2600 °C for 300 s. The phase composition and the microstructure evolution of the composites were investigated. The addition of YB4 promotes the formation of nano t-Zr0.92Y0.08O1.96 crystals, decreasing the phase transition stress in the oxide layer and reducing the volatilization of the glassy phase. However, the addition of Al4SiC4 reduces the melting point of Zr-based oxides and the viscosity of the oxide layer. Therefore, the air plasma torch blows the oxide layer away, leading to the increase of linear recession rate.

Nonstoichiometry Induced Amorphous Grain Boundary of Na5SmSi4O12 Solid-State Electrolyte for Long-Life Dendrite-Free Sodium Metal Battery.

Oxide ceramics are considered promising candidates as solid electrolytes (SEs) for sodium metal batteries. However, the high sintering temperature induced boundaries and pores between angular grains lead to high grain boundary resistance and pathways for dendrite growth. Herein, we report a grain boundary modification strategy, which in situ generates an amorphous matrix among Na5SmSi4O12 oxide grains via tuning the chemical composition. The mechanical properties as well as electron mitigating capability of modified SE have been significantly enhanced. As a result, the SE achieves a room-temperature total ionic conductivity of 5.61 mS cm-1, the highest value for sodium-based oxide SEs. The Na|SE|Na symmetric cell achieves a high critical current density of 2.5 mA cm-2 and excellent cycle life over more than 2800 h at 0.15 mA cm-2 without dendrite formation. The full cell with Na3V2(PO4)3 as the cathode demonstrates impressive cycling performance, maintaining stability over 3000 cycles at 5C without observable loss of capacity.

Molecular dynamics simulation and experimental study of the material machinability characteristics and crack propagation mechanisms for fused silica double nanoscratches

Fused silica is a high-purity, hard and brittle, difficult-to-machine amorphous material that is widely used in the aerospace, optical instruments, semiconductors, microelectronics and other important fields. However, the influence of adjacent scratches on material deformation and subsurface damage during ultraprecision machining by abrasive particles is not well understood. This study aims to investigate the influence of micron-spaced double scratches on the deformation and damage for fused silica through molecular dynamics simulations and double nanoscratch experiments. An amorphous model of fused silica is created using a two-step simulated annealing method with three-directional periodic boundary conditions. Variable loaded double scratches with different nanometer distances are simulated on the surface of the model, and variable loaded double scratch experiments with varying micron-sized distances between scratches are conducted for fused silica wafers. The simulation and experimental results reveal that the deformation of fused silica during nanoscale double scratching involves both elastic and plastic deformation, and the surface and subsurface damage primarily consists of radial, lateral, Hertzian, and median cracks. The distance between the double scratches affects the load variation, surface and subsurface crack propagation, extent of material damage and removal rate, and surface roughness. Examination of the material subsurfaces using the FIB-TEM sample preparation and testing technique shows that the distance between the double scratches also influences the subsurface damage to the material.

Are Critical Fluctuations Responsible for Glass Formation?

The dynamic heterogeneities occurring just before the transition to the glassy phase have been named as the cause of amorphization in supercooled systems. Numerous studies conducted so far have confirmed this hypothesis, and based on it, a widely accepted solution to the puzzle of glass transition has been developed. This report focuses on verifying the existence of a strong pretransitional anomaly near the glass transition Tg. For this purpose, supercooled liquid-crystalline systems with a strong rod-like structure were selected. Based on the obtained experimental data, we demonstrate in this article that the previously postulated dynamic heterogeneities exhibit a critical characteristic, meaning a strong pretransitional anomaly can be observed with the described critical exponent α=0.5. Due to this property, it can be concluded that these heterogeneities are critical fluctuations, and consequently, the transition to the glassy state can be described based on the theory of critical phenomena. To measure the pretransitional anomaly near Tg in supercooled liquid-crystalline systems, broadband dielectric spectroscopy (BDS) and nonlinear dielectric effect (NDE) methods were applied. The exponent α provides insight into the nature and intensity of critical fluctuations in the system. A value of α=0.5 suggests that the fluctuations become increasingly intense as the system approaches the critical point, contributing to the divergence in specific heat. Understanding the role of critical fluctuations in the glass transition is crucial for innovating and improving a wide range of materials for energy storage, materials design, biomedical applications, food preservation, and environmental sustainability. These advancements can lead to materials with superior properties, optimized manufacturing processes, and applications that meet the demands of modern technology and sustainability challenges.

Intranasal delivery of doxepin: enhancing brain targeting efficiency utilizing nanostructured lipid carriers for a biopharmaceutics drug disposition classification system class-I drug.

Doxepin, a Class-I Biopharmaceutics Drug Disposition Classification System (BDDCS) drug, exhibits poor bioavailability due to extensive first-pass metabolism. This research focuses on enhancing the delivery of doxepin by formulating nanostructured lipid carriers (NLCs) through the utilization of the Box-Behnken Design methodology. These optimized NLCs are intended for intranasal administration, with the ultimate goal of improving nose-to-brain drug delivery. NLCs were formulated using a high-speed homogenization technique. The optimized batch had a small particle size (75.80 ± 5.48 nm, PDI = 0.286), high entrapment efficiency (94.10 ± 0.16%), and sustained ex vivo release (82.25 ± 4.61% at 24 h). Characterization studies confirmed the conversion of doxepin from a crystalline to an amorphous state with uniform distribution in the lipid matrix. In vivo pharmacokinetic studies in rats showed significantly higher doxepin concentration in the brain tissue (Cmax = 16.77 µg/g, tmax = 30 min) after intranasal administration compared to intravenous administration (Cmax = 2.53 µg/g, tmax = 6 h). High-drug targeting efficiency (DTE = 284.3%) and direct transport percentage (DTP = 64.8%) suggested direct penetration of NLCs in the brain via olfactory and trigeminal pathways. In conclusion, the study highlights the potential of NLCs to improve the bioavailability of doxepin through nose-to-brain delivery and thereby potentially enable the treatment of neurological disorders.

Applying Machine Learning to Design Delicate Amorphous Micro-Nano Materials for Rechargeable Batteries

As modern society evolves, the global importance of energy requirements has grown significantly. Thus, exploring new materials for renewable energy storage is urgently needed. Due to its intriguing characteristics, amorphous micro-nanomaterials demonstrate exceptional performance in energy storage. The long experimental periods and high costs associated with traditional methods make it challenging to meet the requirements of materials science. Currently, machine learning (ML) is emerging as a novel research paradigm with the potential to revolutionize the exploration of materials. This review provides an overview of the application of ML in studying amorphous micro-nanomaterials for rechargeable batteries. First, a comprehensive introduction to the fundamentals of amorphous materials and ML is summarized. Then, we highlight a series of representative works to elaborate the relationship between the ML for amorphous nanomaterials. Finally, an insightful perspective on utilization of amorphous materials to establish mature energy storage systems and future directions in ML for amorphous materials are presented. Through this review, we aim to unveil the underlying amorphous structure-function relationship and fuel further research in the design of amorphous materials with outstanding performance across diverse fields.

Improved ablation resistance of silicone/phenolic hybrid resin coatings with Zr-Si-O glass as anti-ablation layer

With the development of the new generation space vehicles, traditional phenolic resin (PR)-based coatings are no longer able to meet the increasingly harsh thermal environment. There is an urgent need to develop higher performance PR to ensure the flight safety of aircraft. Therefore, in this work, a novel hyperbranched polysiloxane containing Si-O-Zr bond was synthesized and then introduced into PR to develop homogeneous silicone/phenolic hybrid resin coatings. The TG results indicate that the introduction of Si-O-Zr bonds significantly improves the heat resistance of silicone. During ablation, the hyperbranched polysiloxane will undergo a ceramization to produce SiO2 and ZrO2 particles, both of which will subsequently generate a highly viscous Zr-Si-O glassy phase as anti-ablation layer. With the fluidity and self-healing properties, it can fill the gaps of the carbon layer and cover the surface of the carbon layer, giving the hybrid resin excellent ablative resistance. The linear ablation rate of the hybrid resin can be as low as 0.003 mm/s, which is an 80 % decrease compared to pure PR. The synthesized hybrid resin is expected to act as superior thermal protection coatings for the next generation of spaceflight.

Studies on B-doping during low-temperature growth of nc-Ge thin films via PECVD to mitigate unwanted conduction characteristics from the post-deposition oxygen absorption

Post-deposition O absorption is a common issue in low-temperature grown nc-Ge films, that makes the material unstable and induces high n-type electrical conductivity ∼10−2 S cm−1. An attempt has been made to mitigate the oxygen absorption issue through B doping of the nc-Ge thin film network at a low deposition temperature of ∼220 °C, employing a conventional capacitively coupled PECVD. At a B2H6 flow rate of 3.0 sccm, the incorporation of a restricted quantity of B maintains a narrow band gap of ∼1.04 eV, significantly low conductivity of ∼6.76 ×10−7 S cm−1, activation energy ∼398 meV, and photosensitivity of 6.0. Spectroscopic studies indicated that B doping facilitated reduced O-intake in the nc-Ge matrix, possibly via passivating the grain boundary defects and dangling bonds in the amorphous matrix and inducing the preferential absorption of O atoms in the Ge–O2 configuration compared to its Ge–Ox (x < 2) counterpart. The diminished O-induced carriers and the supplied acceptor levels by the B dopants compensate for the inherent n-type carrier concentration. However, at higher B2H6 flow rates, significant B incorporation in the film matrix introduces numerous defects, degrading the crystallinity, despite increasing its p-type conductivity to 2.16 ×10−5 S cm−1 and maintaining a narrow band gap. Organized switching in the type of conductivity from the n-type to p-type ensues via gradually rising the B-dopants within the nc-Ge thin film network during its growth, which deserves attention for specific device applications.

Studies on B-doping during low-temperature growth of nc-Ge thin films via PECVD to mitigate unwanted conduction characteristics from the post-deposition oxygen absorption

Post-deposition O absorption is a common issue in low-temperature grown nc-Ge films, that makes the material unstable and induces high n-type electrical conductivity ∼10−2 S cm−1. An attempt has been made to mitigate the oxygen absorption issue through B doping of the nc-Ge thin film network at a low deposition temperature of ∼220 °C, employing a conventional capacitively coupled PECVD. At a B2H6 flow rate of 3.0 sccm, the incorporation of a restricted quantity of B maintains a narrow band gap of ∼1.04 eV, significantly low conductivity of ∼6.76 ×10−7 S cm−1, activation energy ∼398 meV, and photosensitivity of 6.0. Spectroscopic studies indicated that B doping facilitated reduced O-intake in the nc-Ge matrix, possibly via passivating the grain boundary defects and dangling bonds in the amorphous matrix and inducing the preferential absorption of O atoms in the Ge–O2 configuration compared to its Ge–Ox (x < 2) counterpart. The diminished O-induced carriers and the supplied acceptor levels by the B dopants compensate for the inherent n-type carrier concentration. However, at higher B2H6 flow rates, significant B incorporation in the film matrix introduces numerous defects, degrading the crystallinity, despite increasing its p-type conductivity to 2.16 ×10−5 S cm−1 and maintaining a narrow band gap. Organized switching in the type of conductivity from the n-type to p-type ensues via gradually rising the B-dopants within the nc-Ge thin film network during its growth, which deserves attention for specific device applications.

The recent progress of single-atom catalysts on amorphous substrates for electrocatalysis

Single-atom catalysts (SACs) have emerged as a focal point in energy catalytic conversion due to their remarkable atomic efficiency and catalytic performance. The challenge lies in efficiently anchoring active sites on a specific substrate to prevent agglomeration, maximizing their effectiveness. Substrate characteristics play a pivotal role in shaping the catalytic performance of SACs, influencing the dispersion and stability of single atoms. In recent years, amorphous materials have gained attention as substrates due to their unique surface structure and abundance of unsaturated coordination sites, offering an ideal platform for capturing and anchoring single atoms effectively, thus enhancing catalytic activity. To clarify the interaction between single atoms and amorphous substrates, this review outlines amorphization methods, the mechanism of single-atom anchoring and the characterization methods of amorphous SACs. Subsequently, it summarizes the physical properties and electrocatalytic mechanisms of amorphous materials. Then, interactions between single atoms and amorphous substrates are categorized and summarized. Finally, the paper consolidates the research progress of amorphous SACs and outlines future development prospects. By exploring the synergistic relationship between single atoms and amorphous substrates, this review aims to deepen the understanding of their interaction mechanisms, thereby propelling advancements in SACs for energy catalytic conversion.