Solid Phase Transition Research Articles

Engineering a triple-functional magnetic gel driving mutually-synergistic mild hyperthermia-starvation therapy for osteosarcoma treatment and augmented bone regeneration

Malignant bone tumors result in high rates of disability and death and are difficult to treat in terms of killing tumors and repairing bone defects. Compared with other hyperthermia strategies, magnetic hyperthermia has become an effective therapy for treating malignant bone tumors due to its lack of depth limitations. However, tumor cells express heat shock protein (HSP) to resist hyperthermia, which reduces its curative effect. Competitive ATP consumption can reduce HSP production; fortunately, the basic principle of starvation therapy by glucose oxidase (GOx) is consuming glucose to control ATP production, thereby restricting HSP generation. We developed a triple-functional magnetic gel (Fe3O4/GOx/MgCO3@PLGA) as a magnetic bone repair hydrogels (MBRs) with liquid‒solid phase transition capability to drive magneto-thermal effects to simultaneously trigger GOx release and inhibit ATP production, reducing HSP expression and thereby achieving synergistic therapy for osteosarcoma treatment. Moreover, magnetic hyperthermia improves the effect of starvation therapy on the hypoxic microenvironment and achieves a reciprocal strengthening therapeutic effect. We further demonstrated that in situ MBRs injection effectively suppressed tumor growth in 143B osteosarcoma tumor-bearing mice and an in-situ bone tumor model in the rabbit tibial plateau. More importantly, our study also showed that liquid MBRs could effectively match bone defects and accelerate their reconstruction via magnesium ion release and enhanced osteogenic differentiation to augment the regeneration of bone defects caused by bone tumors, which generates fresh insight into malignant bone tumor treatment and the acceleration of bone defect repair.

Solid Phase Transitions in the Liquid Limit

We address the fundamental difference between solid-solid and liquid-liquid phase transitions within the Ericksen's nonlinear elasticity paradigm. To highlight ideas, we consider the simplest nontrivial 2D problem and work with a prototypical two-phase Hadamard material which allows one to weaken the rigidity and explore the nature of solid-solid phase transitions in a ``near-liquid'' limit. In the language of calculus of variations we probe limits of quasiconvexity in an ``almost liquid'' solid by comparing the thresholds for cooperative (laminate based) and non-cooperative (inclusion based) nucleation. Using these two types of nucleation tests we obtain for our model material surprisingly tight two-sided bounds on the elastic binodal without directly computing the quasiconvex envelope.

Optically Induced Multistage Phase Transition in Coherent Phonon-Dominated a-GeTe.

Ultrafast photoexcitation can decouple the multilevel nonequilibrium dynamics of electron-lattice interactions, providing an ideal probe for dissecting photoinduced phase transition in solids. Here, real-time time-dependent density functional theory simulations combined with occupation-constrained DFT methods are employed to explore the nonadiabatic paths of optically excited a-GeTe. Results show that the short-wavelength ultrafast laser is capable of generating full-domain carrier excitation and repopulation, whereas the long-wavelength ultrafast laser favors the excitation of lone pair electrons in the antibonded state. Photodoping makes the double-valley potential energy surface shallower and allows the insertion of A1g coherent forces in the atomic pairs, by which the phase reversal of Ge and Te atoms in the ⟨001⟩ direction is activated with ultrafast suppression of the Peierls distortion. These findings have far-reaching implications regarding nonequilibrium phase engineering strategies based on phase-change materials.

Reduction of amorphous carbon clusters from the highly disordered and reduced graphene oxide NPs by acoustical shock waves — Towards the formation of highly ordered graphene

The journey of exploring the acoustical shock wave-induced solid state phase transitions on polymorphic and allotropy materials have gained enormous momentum in recent years after the invention of the tabletop Reddy tube, but, the knowledge of shock wave-induced phase transitions on allotropy materials is very limited in comparison to the polymorphic materials. Hence, in this framework, we report the shock wave-induced transitions based on the reduction of the amorphous carbon clusters in the highly disordered and reduced graphene oxide nanoparticles (rGO NPs) [rGO — is also called as modified graphene]. The reduction of the disordered carbon in the rGO NPs under shocked conditions is examined by the techniques such as X-ray diffractometry and Raman spectrometer. X-ray crystallographic studies clearly present that as the shock pulses are increased, the intensity of the (002) peak is increased for which the authentication is observed by the Raman spectral analyses wherein it is clearly indicated the decrement and increment of the D and G bands against the exposure of the shock pulses thereby the ID/IG ratios are found to be 1.24, 1.17, 1 and 0.927 for 0, 100, 200 and 400 shocks, respectively. According to the Raman spectral results, the area of the amorphous Raman peak is reduced against the shock pulses such that the values are 98, 82, 81 and 48 for the 0, 100, 200 and 400 shocks, respectively. The removal of amorphous carbon clusters in the rGO NPs can be explained on the basis of the conversion of sp3 to sp2 hybridizations based on the shock wave induced hot-spot nucleation mechanism.

Temperature-driven structural phase transitions in CsPbBr[formula omitted

CsPbBr3 possesses soft lattices that, when heated, go through temperature-driven solid–solid phase transitions. By examining Gibbs free energies determined by lattice dynamics simulation, integrating both quasi-harmonic phonons and quasi-anharmonic phonons, this study explores the polymorph stabilities and phase transitions in CsPbBr3. The existence of any additional polymorphs, which are frequent in other metal halide perovskites, was ruled out in CsPbBr3, and three well-known phase transitions (orthorhombic (Pnma) to tetragonal (P4/mbm), then to cubic (Pm3̄m)) were successfully replicated. It has been found that the quasi harmonic approximation QHA, accurately predicts the phase transitions in CsPbBr3. When anharmonicity is introduced, the Gibbs free energy lowers, demonstrating that the intrinsic anharmonicity of the high temperature cubic phase is what gives it its stability. The impact of temperature from the point at which symmetry breaks to the melting point is discussed and investigated.

A framework to simulate the blowout of CO2 through wells in geologic carbon storage

It is important to evaluate the risks associated with CO2 leakage in large scale carbon capture and storage (CCS) projects. Leaky wells are considered a major concern for potential CO2 leakage in geologic carbon storage. The most rapid and spectacular mode of CO2 leakage is the blowout of a CO2 storage well. The Sheep Mountain CO2 blowout in March 1982 is an example of this type of catastrophe wherein several thousand tons of CO2 were released into the atmosphere every day. The blowout was stopped only in early April. In the current work we present a numerical framework to simulate blowouts of CO2 wells accounting for the supercritical-liquid–gas–solid phase transitions of CO2 during the process. It is an in-house finite volume method based code for CO2 transport in open wells, relying on a hybrid Span–Wagner equations of state. We present extensive verification and validation of the code against numerical and experimental data in the literature. When applied to well blowouts, our numerical method is able to identify the locations along the well where CO2 transitions between its different phases. Our simulations show that while the heat transfer between CO2 and the casing has a significant impact on the transient characteristics of the blowout, it does not affect the steady-state leakage rate significantly. We also find that the CO2 leakage rate increases as the total depth of the well increases, with an average leakage rate of 2.09×104 tons per day across all the well depths simulated ranging between 1 km and 3.5 km. Our simulations show that when the temperature and pressure at the well bottom are appreciably lower than the geothermal temperature and hydrostatic pressure at the given depth, CO2 is released as dry ice at the wellhead. The dry ice modeled here has a significant time-averaged mass fraction of 30% at quasi-steady state, and causes rapid fluctuations in the CO2 leakage rate.

Targeting of biomolecular condensates to the autophagy pathway.

Biomolecular condensates are membraneless compartments formed by liquid-liquid phase separation. They can phase transit into gel-like and solid states. The amount and state of biomolecular condensates must be tightly regulated to maintain normal cellular function. Autophagy targets biomolecular condensates to the lysosome for degradation or other purposes, which we term biocondensophagy. In biocondensophagy, autophagy receptors recognize biomolecular condensates and target them to the autophagosome, the vesicle carrier of autophagy. Multiple types of autophagy receptors have been identified and they are specifically involved in targeting biomolecular condensates with different phase transition states. The receptors also organize the phase transition of biomolecular condensate to facilitate biocondensophagy. Here, we briefly discuss the latest discoveries regarding how biomolecular condensates are recognized by autophagy receptors.

A phase transition approach to elucidate the propagation of shear waves in viscoelastic materials

In the field of acoustics, a medium has traditionally been considered a liquid if shear waves cannot propagate. For more complex liquids, such as those containing polymer chains or surfactant aggregates, this definition begins to be unclear. By adopting a rheological model-independent approach, this work investigated by means of dynamic elastography, the liquid–solid phase transitions in viscoelastic liquid media. When the storage shear modulus G′ dominated the loss shear modulus G″, a minimal shear wave attenuation frequency region was defined and the medium was considered solid. When G″ dominated G′, the shear waves were strongly attenuated and the medium was considered liquid. The investigated medium, an aqueous solution of xanthan gum, behaved as a bandpass filter with transition bands, showing liquid–solid–liquid behavior from low to high frequency. During these transitions bands, shear waves still propagated but highly attenuated. The limiting values where shear waves were no longer observed were identified as the low and high cutoff frequencies. Finally, the ability of various rheological models to predict the phase transition frequencies and describe the dispersion curves was tested. A three-element rheological model, the Jeffreys model, was required to accurately fit the experimental response of the medium at different concentrations over the entire frequency range. Shear wave propagation methods can overcome the technical limitations of traditional rheometry and explore higher frequencies, rarely investigated in viscoelastic liquids.

Characterizing the thermal phase behaviour of fipronil polymorphs

This manuscript reports the investigation of the polymorphic behaviour of fipronil using a systematic comparison of the thermochemical and structural properties of different crystal forms obtained in this study as well as those previously reported in literature. The analytical techniques employed include DSC, TGA, PXRD, SCXRD and hot stage microscopy. DSC proved particularly useful because it made it possible to differentiate between the two different crystal forms found in the as-received neat fipronil. The DSC scans revealed the presence of two polymorphs which had melting endotherms with peak maxima at ca. 196 °C and 205 °C, respectively. These polymorphs were successfully separated via sublimation and resulted in a metastable, lower melting polymorph in the sublimate and a thermodynamically stable, higher melting form in the sublimation residue. Clear evidence for the instability of the lower melting polymorph was found when the endotherms were examined under a range of heating rates. The proportion of the metastable form appeared to increase as the rate was increased, indicating that the metastable form underwent a solid–solid phase transition to the stable form at low heating rates. Recrystallization of fipronil from different solvents yielded five different forms. TGA curves revealed that all forms, except the acetone-derived one, were solvate pseudo-polymorphs that showed solvent loss between 60 and 100 °C. The acetone-derived sample was a hemihydrate that only started to show mass loss at 120 °C. SCXRD studies revealed that three of the five forms have similar structural characteristics, while the other two forms differ notably from each other and the rest of the structures. Despite these structural differences, all five forms exhibit near-identical intra- and intermolecular hydrogen bond networks.

Diamond-TiC composite with an ultrahigh Hugoniot elastic limit

The Hugoniot elastic limit (HEL) is widely adopted as an important criterion for assessing the dynamic strength of materials, representing the transition stress from elastic to plastic response prior to failure under shock compression. Nano-polycrystalline diamond currently holds the highest HEL of 208 (±14) GPa. Here, we report a diamond-TiC composite (∼11.5 wt. % TiC) showing an ultrahigh HEL of at least 195 (±3.5) GPa, which is comparable to that of nano-polycrystalline diamond. All measured velocity profiles on the diamond-TiC free surface exhibited a single-wave structure at shock pressures of 48–195 GPa. Moreover, the measured Us–Up (shock wave velocity–particle velocity) relation can be linearly fitted, indicating no elastic–plastic transition or solid–solid phase transition up to a shock pressure of 195 GPa. The diamond-TiC composite's compression ratio was similar to that of TiC but significantly higher than that of diamond. These extraordinary dynamic responses are intrinsically attributed to the unique microstructure in which diamond polycrystals are encased in a TiC matrix, providing protection against yielding. Our findings not only developed a mechanically reliable, lightweight, and high-performance armor material at low synthesis costs, but also provided new insights into the shock compression behavior of diamond composites.

Unraveling the Complex Solid-State Phase Transition Behavior of 1-Iodoadamantane, a Material for Which Ostensibly Identical Crystals Undergo Different Transformation Pathways.

Phase transitions in crystalline molecular solids have important implications in the fundamental understanding of materials properties and in the development of materials applications. Herein, we report the solid-state phase transition behavior of 1-iodoadamantane (1-IA) investigated using a multi-technique strategy [synchrotron powder X-ray diffraction (XRD), single-crystal XRD, solid-state NMR, and differential scanning calorimetry (DSC)], which reveals complex phase transition behavior on cooling from ambient temperature to ca. 123 K and on subsequent heating to the melting temperature (348 K). Starting from the known phase of 1-IA at ambient temperature (phase A), three low-temperature phases are identified (phases B, C, and D); the crystal structures of phases B and C are reported, together with a re-determination of the structure of phase A. Remarkably, single-crystal XRD shows that some individual crystals of phase A transform to phase B, while other crystals of phase A transform instead to phase C. Results (from powder XRD and DSC) on cooling a powder sample of phase A are fully consistent with this behavior while also revealing an additional transformation pathway from phase A to phase D. Thus, on cooling, a powder sample of phase A transforms partially to phase C (at 229 K), partially to phase D (at 226 K) and partially to phase B (at 211 K). During the cooling process, each of the phases B, C, and D is formed directly from phase A, and no transformations are observed between phases B, C, and D. On heating the resulting triphasic powder sample of phases B, C, and D from 123 K, phase B transforms to phase D (at 211 K), followed by the transformation of phase D to phase C (at 255 K), and finally, phase C transforms to phase A (at 284 K). From these observations, it is apparent that different crystals of phase A, which are ostensibly identical at the level of information revealed by XRD, must actually differ in other aspects that significantly influence their low-temperature phase transition pathways. This unusual behavior will stimulate future studies to gain deeper insights into the specific properties that control the phase transition pathways in individual crystals of this material.

Sound velocities of natural goethite across α–ɛ phase transformation under dynamic compression

Goethite (α-FeOOH), a vital water- and hydrogen-bearing natural mineral, is extensively distributed on the Earth's surface and probably in the lower mantle. Laboratory measurements of its phase transition and sound velocities provide crucial data for a more rational understanding of the deep-water transportation and physical properties of the Earth's interior. Herein, the Hugoniot equation of state and sound velocities of natural goethite up to around 15 GPa are measured by dynamic compression. The discontinuities pertinent to the density and sound velocities of goethite are observed at 7.1 (2) GPa, in which a solid–solid phase transition occurs from α- (Pbnm) to ɛ-FeOOH (P21nm). Through this structural phase transition, the longitudinal and shear wave velocities in order, enhance by about 5% and 12%. We suggest that changes in the sound velocity due to the FeOOH phase transition may contribute to the discontinuity in the subduction zones.

Magnetic Switchability via Thermal-Induced Structural Phase Transitions in Molecular Solids

Magnetically switchable molecular solids with stimuli-responsive ON/OFF characteristics are promising candidates for smart switches and magnetic storage. In addition to conventional spin-crossover/charge-transfer materials whose magnetic responses arise from changes in the electronic structure of the metal centers, peripheral chemical entities that exhibit tunability provide an alternative and promising tactic for the construction of magnetic multi-stable materials. Temperature changes can trigger a reversible structural phase transition that can affect the coordination environment of a transition-metal center because of the thermal-induced motion of ligands, counterions, neutral guests, and/or changes in coordination number, thus potentially realizing magnetic bistability which can arise from a concomitant spin state change or the modulation of orbital angular momentum. Perspectives and challenges are also highlighted to provide insights into its development.

Influence of self-nucleation on phase transition in poly(1-butene)

The self-nucleation effect is often investigated to focus on kinetics and polymorphism of melt crystallization. In this work, the effect of self-nucleation on solid phase transition from the tetragonal phase into the thermodynamically most stable trigonal phase was studied with differential scanning calorimetry (DSC) for the isotactic poly(1-butene). With respect to the initial completely relaxed melt in Domain I, self-nucleation treatment of Domains II and III show the opposite influences on phase transition kinetics, where the former accelerates phase transition but the latter inhibits phase transition. Employing isothermal crystallization experiments, it is found that at the lowered self-nucleation temperature (Ts), the further accelerated phase transition was caused by the enlarged internal stress, which triggers nucleation of form I within form II. Interestingly, although cooling crystallization can be enhanced as Ts was cooled into Domain III, the corresponding phase transition of obtained crystallites was inhibited, even slower than that of relaxed melt in Domain I. As Ts was further lowered to 115 °C with the increased isothermal time, the initial crystallites not only survive but also thicken during the isothermal process at Ts. More interestingly, the annealed crystallites exhibited the most suppressed phase transition. The accelerated phase transition by Ts of Domain II was related to the increased internal stress, which drives the nucleation of transformed trigonal phase within the original tetragonal phase. Differently, the inhibited phase transition by self-nucleation of Domain III was associated with the reduced links between lamellae and amorphous region, which facilitates the transfer of internal stress.

Influence of ALS-linked M337V mutation on the conformational ensembles of TDP-43321-340 peptide monomer and dimer.

The transactive response (TAR) DNA/RNA-binding protein 43 (TDP-43) can self-assemble into both functional stress granules via liquid-liquid phase separation (LLPS) and pathogenic amyloid fibrillary aggregates that are closely linked to amyotrophic lateral sclerosis. Previous experimental studies reported that the low complexity domain (LCD) of TDP-43 plays an essential role in the LLPS and aggregation of the full-length protein, and it alone can also undergo LLPS to form liquid droplets mainly via intermolecular interactions in the 321-340 region. And the ALS-associated M337V mutation impairs LCD's LLPS and facilitates liquid-solid phase transition. However, the underlying atomistic mechanism is not well understood. Herein, as a first step to understand the M337V-caused LLPS disruption of TDP-43 LCD mediated by the 321-340 region and the fibrillization enhancement, we investigated the conformational properties of monomer/dimer of TDP-43321-340 peptide and its M337V mutant by performing extensive all-atom explicit-solvent replica exchange molecular dynamic simulations. Our simulations demonstrate that M337V mutation alters the residue regions with high helix/β-structure propensities and thus affects the conformational ensembles of both monomer and dimer. M337V mutation inhibits helix formation in the N-terminal Ala-rich region and the C-terminal mutation site region, while facilitating their long β-sheet formation, albeit with a minor impact on the average probability of both helix structure and β-structure. Further analysis of dimer system shows that M337V mutation disrupts inter-molecular helix-helix interactions and W334-W334 π-π stacking interactions which were reported to be important for the LLPS of TDP-43 LCD, whereas enhances the overall peptide residue-residue interactions and weakens peptide-water interactions, which is conducive to peptide fibrillization. This study provides mechanistic insights into the M337V-mutation-induced impairment of phase separation and facilitation of fibril formation of TDP-43 LCD.

Dynamics of bacterial ribonucleoprotein bodies probed by single-molecule fluorescence imaging of RNase E.

Ribonucleoprotein (RNP) bodies that exhibit liquid-like internal dynamics facilitate processes such as rRNA transcription and processing, while RNP bodies with gel- or solid-like dynamics (e.g., P-bodies and stress granules) facilitate processes such as mRNA storage. Recently, it has been shown that bacterial RNA degradosomes can assemble into phase-separated condensates called bacterial ribonucleoprotein bodies (BR-bodies). In Caulobacter crescentus, BR-bodies are dynamic and exhibit liquid-like properties, consistent with their mRNA degradation activity. However, under cell stress, the number of BR-bodies increases significantly to give C. crescentus cells a fitness advantage. Furthermore, upon entrance into the stationary phase, an increased number of BR-bodies correlates with a slowdown in the mRNA decay rate. These results raise the question of whether BR-bodies can facilitate mRNA storage. Here, we use bulk fluorescence imaging and live-cell single-molecule tracking to probe the dynamics of the ribonuclease RNase E, the central scaffold of the BR-body. We found that during stationary phase, BR-bodies are stable for longer have a longer compared to exponential phase. Consistent with these results, the residence time of RNase E in BR-bodies in stationary phase cells is at least two orders of magnitude longer than in exponential phase cells. Finally, we measured the size and abundance of BR-bodies during both growth stages and found that during stationary phase, BR-bodies are smaller and more abundant, which suggests that the condensate phase is not conducive to fusion. Together, our data shows an increased stability of RNAse E in the stationary phase, which may indicate a gel or solid phase transition. Furthermore, we anticipate our single-molecule measurements will provide a foundation for probing the mechanical properties of subcellular compartments in living bacteria.

Synchronous Visual/Infrared Stealth Using an Intrinsically Flexible Self‐Healing Phase Change Film

AbstractPhase change materials (PCMs) have been particularly concerned as infrared stealth functional materials due to their superior thermal management capability. However, traditional PCMs usually behave rigid solid or flowing liquid states with fixed transition temperature, greatly limiting their application especially in multi‐band stealth and multiple scenes. Herein, an intrinsically flexible self‐healing phase change film used for synchronous visual/infrared stealth for the first time is designed and constructed. The phase change film possesses a solid–solid phase transition behavior with adjustable transition temperature (from 38.8 to 51.1 °C) and enthalpy (from 79.7 to 116.7 J g−1), long‐term cycling stability (500 cycles), and outstanding flexible and self‐healing performance. Remarkably, the phase change film can be customized with different colors and various configurations to exhibit attractive visual stealth functions in multiple scenes. Additionally, owing to phase transition property, this phase change film can possess a thermal management capability and behave infrared stealth performance for objectives at various temperatures. Combining the above unique functions, the intrinsically flexible self‐healing phase change film developed in this work may show great potential for applications in the synchronous visual/infrared stealth across a wide range of scenarios and temperatures.

High-Performance Heat Storage Phase Change Composite by Highly Aligned N-Doped Mesoporous Carbon for Efficient Battery Thermal Management

Limited by leakage from inherent liquid to solid phase transition and inferior heat transfer, pristine organic phase change materials (PCMs) possess extremely low thermal storage performance. Thus, establishing shape-stable PCM composites with enhanced thermal conductivity and latent heat is a key task for practical application. Herein, we constructed N-doped mesoporous carbon monoliths with a highly aligned structure by directional freeze-drying to encapsulate polyethylene glycol. Benefiting from the mesoporous carbon matrix and pyridinic N from N-doping, the PCM composite possessed large latent heat (140 J·g–1) and leakage proof at 80 °C. Meanwhile, the highly aligned structure created a fast heat transfer pathway that improved thermal conductivity of the PCM composite by 1500%. Being different from most research studies, highly aligned carbon was utilized as the support directly without skeletons, which could increase PCM loading capacity and thermal conductivity as well. The PCM composite can be employed as promising candidates for thermal management working efficiently to decrease battery pack temperature by 13 °C and improve discharge capacity by 28%.

Dynamics of the fcc-to-bcc phase transition in single-crystalline PdCu alloy nanoparticles

Two most common crystal structures in metals and metal alloys are body-centered cubic (bcc) and face-centered cubic (fcc) structures. The phase transitions between these structures play an important role in the production of durable and functional metal alloys. Despite their technological significance, the details of such phase transitions are largely unknown because of the challenges associated with probing these processes. Here, we describe the nanoscopic details of an fcc-to-bcc phase transition in PdCu alloy nanoparticles (NPs) using in situ heating transmission electron microscopy. Our observations reveal that the bcc phase always nucleates from the edge of the fcc NP, and then propagates across the NP by forming a distinct few-atoms-wide coherent bcc–fcc interface. Notably, this interface acts as an intermediate precursor phase for the nucleation of a bcc phase. These insights into the fcc-to-bcc phase transition are important for understanding solid − solid phase transitions in general and can help to tailor the functional properties of metals and their alloys.

Molecular screening for solid–solid phase transitions by machine learning

The solid–solid phase transition in molecular solids can be predicted by positive-unlabeled learning using molecular descriptors.