Condensation Formation Research Articles

GPX modulation promotes regenerative axonal fusion and functional recovery after injury through PSR-1 condensation

Axonal fusion represents an efficient way to recover function after nerve injury. However, how axonal fusion is induced and regulated remains largely unknown. We discover that ferroptosis signaling can promote axonal fusion and functional recovery in C. elegans in a dose-sensitive manner. Ferroptosis-induced lipid peroxidation enhances injury-triggered phosphatidylserine exposure (PS) to promote axonal fusion through PS receptor (PSR-1) and EFF-1 fusogen. Axon injury induces PSR-1 condensate formation and disruption of PSR-1 condensation inhibits axonal fusion. Extending these findings to mammalian nerve repair, we show that loss of Glutathione peroxidase 4 (GPX4), a crucial suppressor of ferroptosis, promotes functional recovery after sciatic nerve injury. Applying ferroptosis inducers to mouse sciatic nerves retains nerve innervation and significantly enhances functional restoration after nerve transection and resuture without affecting axon regeneration. Our study reveals an evolutionarily conserved function of lipid peroxidation in promoting axonal fusion, providing insights for developing therapeutic strategies for nerve injury.

Sequence-Dependent Liquid Crystalline Ordering of Gapped DNA.

We investigate the impact of poly adenine (poly-A) sequences on the type and stability of liquid crystalline (LC) phases formed by concentrated solutions of gapped DNA (two duplex arms bridged by a flexible single strand) using synchrotron small-angle X-ray scattering and polarizing optical microscopy. While samples with mixed sequence form layered (smectic) phases, poly-A samples demonstrate a columnar phase at lower temperatures (5-35 °C), not previously observed in GDNA samples, and a smectic-B phase of exceptional stability at higher temperatures (35-65 °C). We present a model that connects the formation of these LC phases with the unique characteristics of poly-A sequences, which manifest in various biological contexts, including DNA condensation and nucleosome formation.

Detection of Guanine Quadruplexes by Raman Optical Activity and Quantum-Chemical Interpretation of the Spectra.

Quadruplexes formed by guanine derivatives or guanine-rich nucleic acids are involved in metabolism and genetic storage of many living organisms, they are used in DNA nanotechnologies or as biosensors. Since many quadruplex geometries are possible the determination of their structures in aqueous solutions is difficult. Raman optical activity (ROA) can make it easier: For guanosine monophosphate (GMP), we observed a distinct change of the spectra upon its condensation and quadruplex formation. The vibrational bands become more numerous, stronger, and narrower. In particular, a huge ROA signal appears below 200 cm-1. The aggregation can be induced by high concentration, low temperature, or by a metal ion. We focused on well-defined quadruplexes stabilized by potassium, where using molecular dynamics and density functional theory the spectra and particular features related to GMP geometric parameters could be understood. The simulations explain the main experimental trends and confirm that the ROA spectroscopy is sensitive to fine structural details, including guanine base twist in the quadruplex helix.

Design, Synthesis, and Biological Evaluation of Novel Heterocyclic Derivatives of 2,4‐Thiazolidine Dione as Anti‐Cancer Agents

ABSTRACTThis study explores the development of novel 2,4‐thiazolidinedione derivatives as potential anticancer agents. We report the synthesis of 15 novel analogs utilizing a strategic approach focused on intermediate diversification. Key intermediates, (Z)‐5‐([1,1′‐biphenyl]‐4‐ylmethylene)thiazolidine‐2,4‐dione 5a and (Z)‐5‐(benzo[1,3]dioxol‐5‐ylmethylene)thiazolidine‐2,4‐dione 5b, were synthesized via Knoevenagel condensation and acetal formation reactions, respectively. Subsequent N‐alkylation reactions provided a platform for introducing diverse functionalities and exploring structure–activity relationships to optimize the medicinal chemistry profile of these novel compounds. The synthesized compounds were tested against various human cancer cell lines, including for breast (MCF‐7, MDA‐MB‐453), lung (A549), and prostate (PC‐3) cancers, using an MTT assay. Compounds 8c and 10g emerged as particularly promising, exhibiting activity against all tested cell lines with IC50 values between 3.41 ± 0.51 and 40 μM. These compounds also induced apoptosis, suggesting that they inhibit cell proliferation through this cell death pathway. Moreover, relative molecular docking studies provided evidence that compound 8c likely functions by intercalating with DNA.

Loss of MMP9 disturbs cranial suture fusion via suppressing cell proliferation, chondrogenesis and osteogenesis in mice

Cranial sutures function as growth centers for calvarial bones. Abnormal suture closure will cause permanent cranium deformities. MMP9 is a member of the gelatinases that degrades components of the extracellular matrix. MMP9 has been reported to regulate bone development and remodeling. However, the function of MMP9 in cranial suture development is still unknown. Here, we identified that the expression of Mmp9 was specifically elevated during fusion of posterior frontal (PF) suture compared with other patent sutures in mice. Interestingly, inhibition of MMP9 ex vivo or knockout of Mmp9 in mice (Mmp9-/-) disturbed the fusion of PF suture. Histological analysis showed that knockout of Mmp9 resulted in wider distance between osteogenic fronts, suppressed cell condensation and endocranial bone formation in PF suture. Proliferation, chondrogenesis and osteogenesis of suture cells were decreased in Mmp9-/- mice, leading to the PF suture defects. Moreover, transcriptome analysis of PF suture revealed upregulated ribosome biogenesis and downregulated IGF signaling associated with abnormal closure of PF suture in Mmp9-/- mice. Inhibition of the ribosome biogenesis partially rescued PF suture defects caused by Mmp9 knockout. Altogether, these results indicate that MMP9 is critical for the fusion of cranial sutures, thus suggesting MMP9 as a potential therapeutic target for cranial suture diseases.

E242-E261 region of MYC regulates liquid-liquid phase separation and tumor growth by providing negative charges

MYC is one of the most extensively studied oncogenic proteins and is closely associated with the occurrence and progression of many tumors. Previous studies have shown that MYC regulates cell fate through its liquid-liquid phase separation (LLPS) mechanism, which is dependent on two disordered domains within its N-terminal transcriptional activation regions. In this study, we revealed that the negatively charged conserved region (E242-E261) of the MYC protein controls its condensation formation and irreversible aggregation through multivalent electrostatic interactions (MEIs). Furthermore, deletion or mutation of the E242-E261 amino acids in the MYC protein enhances the transcriptional function of MYC by altering its aggregation capacity and subsequently promoting cancer cell proliferation. The discovery of the negatively charged region and its regulatory action on the phase separation of MYC provides a new understanding on the aggregation and function of MYC.

Detecting axion dark matter with black hole polarimetry

The axion, as a leading dark matter candidate, is the target of many ongoing and proposed experimental searches based on its coupling to photons. Ultralight axions that couple to photons can also cause polarization rotation of light which can be probed by the cosmic microwave background. In this work, we show that a large axion field is inevitably developed around black holes due to the Bose-Einstein condensation of axions, enhancing the induced birefringence effects. Therefore, measuring the modulation of supermassive black hole imaging polarization angles is a strong probe to the axion-photon coupling due to the formation of the axion condensation (axion star) which enhances the axion field. The oscillating axion field around black holes induces polarization rotation on the black hole image, which is detectable and distinguishable from astrophysical effects on the polarization angle, as it exhibits distinctive temporal variability and frequency invariability. In this work, we perform the theoretical calculation on the axion star formation rate and correspondingly the enhanced axion field value near supermassive black holes. Then, we present the range of axion-photon couplings within the axion mass range 10−21–10−16 eV that can be probed by the Event Horizon Telescope. The axion parameter space probed by black hole polarimetry will expand with the improvement in sensitivity on the polarization measurement and more black hole polarimetry targets with determined black hole masses. Published by the American Physical Society 2024

Catalytic pyrolysis mechanism of lignin moieties driven by aldehyde, hydroxyl, methoxy, and allyl functionalization: the role of reactive quinone methide and ketene intermediates.

The catalytic pyrolysis of guaiacol-based lignin monomers, vanillin, syringol, and eugenol over commercial HZSM-5 has been investigated using operando Photoelectron Photoion Coincidence (PEPICO) spectroscopy to unveil the reaction mechanism by detecting reactive intermediates, such as quinone methides and ketenes, and products. Vanillin shares the decomposition mechanism with guaiacol due to prompt and efficient decarbonylation, which allows us to control this reaction leading to a phenol selectivity increase by switching to a faujasite catalyst and decreasing the Si/Al ratio. Syringol first demethylates to 3-methoxycatechol, which mainly dehydroxylates to o- and m-guaiacol. Ketene formation channels over HZSM-5 are less important here than for guaiacol or vanillin, but product distributionremains similar. C3 addition to guaiacol yields eugenol, which shows a more complex product distribution upon catalytic pyrolysis. By analogies to monomers with simplified functionalization, namely allylbenzene, 4-allylcatechol, and 4-methylcatechol, the eugenol chemistry could be fully resolved. Previously postulated reactive semi-quinone intermediates are detected spectroscopically, and their involvement opens alternative pathways to condensation and phenol formation. Allyl groups, produced by dehydroxylation of the β-O-4 bond, may not only decompose via C1/C2/C3 loss, but also cyclize to indene and its derivatives over HZSM-5. This comparably high reactivity leads to an unselective branching of the chemistry and to a complex product distribution, which is difficult to control. Indenes and naphthalenes are also prototypical coke precursors efficiently deactivating the catalyst. We rely on these mechanistic insights to discuss strategies to fine-tune process conditions to increase the selectivities of desired products by enhancing either vanillin and guaiacol or supressing eugenol yields from native lignin.

Mass Cycle and Dynamics of a Virtual Quiescent Prominence

The mass cycle of solar prominences or filaments is still not completely understood. Researchers agree that these dense structures form by coronal in situ condensations and plasma siphoning from the underlying chromosphere. In the evaporation–condensation model siphoning arises due to evaporation of chromospheric plasma from localized footpoint heating, but this is challenging to justify observationally. Here, we simulate the reconnection–condensation model at extreme resolutions down to 20.8 km within a three-dimensional (3D) magnetohydrodynamic coronal volume. We form a draining, quiescent prominence and associated coronal rain simultaneously. We show that thermal instability—acting as a trigger for local condensation formation—by itself drives siphoning flows from the low corona without the need of any localized heating. In addition, for the first time, we demonstrate through a statistical analysis along more than 1000 magnetic field lines that cold condensations give rise to siphoning flows within magnetic threads. This siphoning arises from the strong pressure gradient along field lines induced by thermal instability. No correlation is found between siphoning flows and the prominence mass, making thermal instability the main in situ mass-collection mechanism. Our simulated prominence drains by gliding along strongly sheared, asymmetric, dipped magnetic arcades, and develops natural vertical fine structure in an otherwise horizontal magnetic field due to the magnetic Rayleigh–Taylor instability. By synthesising our data, our model shows remarkable agreement with observations of quiescent prominences such as its dark coronal cavity in extreme-ultraviolet emission channels, fine-scale vertical structure, and reconnection outflows, which, for the first time, have been self-consistently obtained as the prominence evolves.

Spurious signals identification in Brillouin light scattering spectrum

AbstractBrillouin light scattering (BLS) is the inelastic scattering of light from elementary excitations with periodic density modulation. The characteristics of non‐contact, high sensitivity, and high resolution in energy, wavevector, time, space, and phase make the BLS spectrometer widely used in investigating many intriguing physical phenomena, including the acoustic phonon confinement effects, Bose‐Einstein condensation (BEC), supercurrent, and soliton formation. Generally, the quick and correct assignment of the signals in the BLS spectra is a prerequisite for further investigations. Herein, we experimentally identify the high‐order spurious signals in the BLS spectra, which make the interpretation of the spectra difficult. The additional signals are demonstrated to originate from the laser and the temperature‐controlled laser filter used for laser filtering. Our results would contribute to the rapid assignment of the signals from the sample after excluding the spurious signals reported here. Moreover, the series of high‐order modes spaced by the free spectral range can serve as a weak broadband light source, which has great potential for investigating the optical responses of materials.

Desalination setup coated by silicone epoxy nanocomposite: A study on hydrophobic characteristics and condensation mechanisms

The formation of tortuous filmwise condensation in desalination setup alongside with reduction in thermal conductivity is a challenge accompanied by efficiency loss. This issue is directly influenced by hydrophobicity, which is a function of surface roughness, as well as surface chemistry. In this sense, the hydrophobicity of variant silicone epoxy based nanocomposites was evaluated to identify the optimum proportion composite for surface condensation of desalination setup. To this end, three types of fumed silica with distinct surface chemistry were utilized in a matrix at the weight percentage of 0.5, 1, 1.5, and 2. To investigate the hydrophobicity, roughness, and distribution of reinforcement, a series of characterization techniques, including contact angle, AFM, and FESEM were used. It was found that, in comparison to pure matrix, the nanocomposite modified with 5 wt % of hydrophobic additive and 0.5 wt % of hydrophilic fumed silica nanoparticles (SE/5B/0.5R200) has the highest contact angle (about 35%) and roughness (13 times), due to the migration of nanoparticle onto the surface. Also, coating the condensation surface of the desalination setup with optimum thickness, i.e. 60 × 10−6 m, resulted in the efficiency improvement by about 33 % compared to the uncoated setup, even after 168 hrs. Indeed, dropwise condensation, straight path movement of droplets, besides thermal conductivity adjust the efficiency.

Selective Excitation of Exciton-Polariton Condensate Modes in an Annular Perovskite Microcavity.

Exciton-polariton systems composed of a light-matter quasi-particle with a light effective mass easily realize Bose-Einstein condensation. In this work, we constructed an annular trap in a halide perovskite semiconductor microcavity and observed the spontaneous formation of symmetrical petal-shaped exciton-polariton condensation in the annular trap at room temperature. In our study, we found that the number of petals of the petal-shaped exciton-polariton condensates, which is decided by the orbital angular momentum, is dependent on the light intensity distribution. Therefore, the selective excitation of perovskite microcavity exciton-polariton condensates under all-optical control can be realized by adjusting the light intensity distribution. This could pave the way to room-temperature topological devices, optical cryptographical devices, and new quantum gyroscopes in the exciton-polariton system.

Frequency-Dependent Microelectrophoresis Study of Colloids with Tunable Surface Charge.

Nonaqueous poly(methyl methacrylate) (PMMA) colloidal suspensions in a solvent that is simultaneously matched in both density and refractive index have been important for real-space studies of colloidal self-assembly, but their complex electrostatic character remains largely unexplored. Electrophoresis is a powerful tool for determining the surface potential and charge of the colloidal suspension; however, because of refractive index matching, standard electrophoresis measurements are not feasible. We carry out microscope-based microelectrophoresis measurements on PMMA colloids in cyclohexyl bromide and cis-trans decalin to measure particle charge as a function of salt concentration in both DC and frequency-variable AC fields. The colloid charge depends on salt concentration and reverses sign near 0.35 μM, providing evidence that solution ions are actively modifying the colloid surface. The frequency dependence of the electrophoretic mobility yields the characteristic time scale for electric double-layer polarization and provides intriguing evidence for Manning condensation and polyion formation.

Numerical simulation of condensation flows of humid air in the high-pressure pneumatic pressure-reducing valve

The phenomenon of condensation and ice formation exists in the high-pressure air pressure-reducing valve (HPAPRV), severely impacting the pressure-reducing valve's aerodynamic performance and operational safety. The problem is that the phase change of humid air in a high-pressure supersonic flow is not fully understood. This study aims to elucidate the condensation effect in high-pressure supersonic flows and the influence of the inlet conditions on the behavior of the condensate flow. A computational humid air phase model has been developed to investigate the formation of massive droplets due to phase-change processes. The numerical approach is validated by comparing it with experimental data, demonstrating a strong correlation between the two. The condensation properties of humid air in HPAPRV are described in detail. The effects of the condensation properties of humid air at different inlet conditions are discussed in detail. The results show that an increase in the inlet pressure increases the level of supersaturation, which increases the nucleation rate and the droplet growth rate and promotes droplet production. Increasing the inlet temperature has little effect on the HPAPRV pressure-reducing performance and predicts the temperature range of water vapor condensation before and after the valve port. The liquid mass fraction can be reduced by 50.9% by increasing the inlet temperature by 30 K, from 283 K to 313 K. When the inlet temperature is below 283 K, water vapor condenses in front of the valve port. Decreasing the inlet humidity reduces the degree and extent of supersaturation, which decreases the nucleation rate and the liquid mass fraction. When low inlet humidity (under 10%), the condensation phenomenon did not almost occur inside the pressure-reducing valve.

RNA modulates hnRNPA1A amyloid formation mediated by biomolecular condensates

Several RNA binding proteins involved in membraneless organelles can form pathological amyloids associated with neurodegenerative diseases, but the mechanisms of how this aggregation is modulated remain elusive. Here we investigate how heterotypic protein–RNA interactions modulate the condensation and the liquid to amyloid transition of hnRNPA1A, a protein involved in amyothropic lateral sclerosis. In the absence of RNA, formation of condensates promotes hnRNPA1A aggregation and fibrils are localized at the interface of the condensates. Addition of RNA modulates the soluble to amyloid transition of hnRNPA1A according to different pathways depending on RNA/protein stoichiometry. At low RNA concentrations, RNA promotes both condensation and amyloid formation, and the catalytic effect of RNA adds to the role of the interface between the dense and dilute phases. At higher RNA concentrations, condensation is suppressed according to re-entrant phase behaviour but formation of hnRNPA1A amyloids is observed over longer incubation times. Our findings show how heterotypic nucleic acid–protein interactions affect the kinetics and molecular pathways of amyloid formation.

Investigation into a Tetrahydroquinazoline Scaffold

AbstractA new 5,6,7,8‐tetrahydroquinazoline (i. e. 1,3‐diazanaphthalene) scaffold with four points of diversification RA−RD was prepared. The sequence started from nitroalkanes RCCH2NO2 (with RC = Me, Bu), ethyl acrylate and amidines RAC(NH)NH2 (with RA = Ph, 4‐pyridyl) which were converted in a conjugate addition, Dieckmann condensation and pyrimidine ring formation. After transformation of the OH group in 4‐position to a chloro leaving group, residues RB were introduced by nucleophilic substitution with alkyl amines RBNH2 (10 examples) or aryl thiols RBSH (two examples). Finally, the nitro group in the 6‐position was reduced and the primary amino function amidated with various carboxylic acids RDCO2H. Along this seven‐step sequence, eight examples of the fully decorated scaffold were prepared.

Bifunctional tissue-engineered composite construct for bone regeneration: The role of copper and fibrin.

Bifunctional tissue engineering constructs promoting osteogenesis and angiogenesis are essential for bone regeneration. Metal ion-incorporated scaffolds and fibrin encapsulation attract much attention due to low cost, nontoxicity, and tunable control over ion and growth factor release. Herein, we investigated the effect of Cu.nHA/Cs/Gel scaffold and fibrin encapsulation on osteogenic and angiogenic differentiation of Wharton's jelly mesenchymal stem cells (WJMSCs) in vitro and in vivo. Cu-laden scaffolds were synthesized using salt leaching/freeze drying and were characterized using standard techniques. WJMSCs were isolated from the human umbilical cord and characterized. WJMSCs with or without encapsulating in fibrin were seeded onto scaffolds, followed by differentiating into the osteogenic lineage for 7 and 21 days. Osteogenic and angiogenic differentiation were evaluated using real-time polymerase chain reaction, western blot, and Alizarin red staining. Then, scaffolds were implanted into critical-sized calvarial bone defects in rats and histological assessments were performed using hematoxylin/eosin, Masson's trichrome, and CD31 immunohistochemical staining at 4 and 12 weeks. The scaffolds had good physicochemical and biological characteristics suitable for cell attachment and growth. Cu and fibrin increased the expression of ALP, RUNX2, OCN, COLI, VEGF, and HIF1α in differentiated WJMSCs. Implanted scaffolds were also biocompatible and were integrated well with the host tissue. Increased collagen condensation, mineralization, and blood vessel formation were observed in Cu-laden scaffolds. The fibrin-encapsulated groups showed the highest collagen and cell densities, immune cell infiltration, and bone trabeculae. CD31-positive cell population increased with fibrin encapsulation and seeding onto Cu-laden scaffolds. Adding Cu to scaffolds and encapsulating cells in fibrin are promising methods that guide osteogenesis and angiogenesis cellular signaling, leading to better bone regeneration.

Molecular structure, characterization, in vitro and in-silico studies of N,N-dimethyl aminophenyl schiff's base-chalcone hybrid

This study reports the synthesis and characterization of a novel compound, a chalcone-based Schiff base (SBC), with potential applications in anti-inflammatory and anti-diabetic treatments. Chalcones, known for their diverse biological activities, are combined with Schiff bases, versatile compounds, to create the SBC. The synthesis process involves aldol condensation and Schiff base formation. The compound's structure is confirmed through NMR, FT-IR, and mass spectroscopic analyses. The UV–visible spectroscopy reveals the compound's electronic properties, and molecular docking experiments indicate its potential to interact with enzymes related to inflammation and diabetes. Anti-inflammatory activity is evaluated through a protein denaturation assay using bovine serum albumin. SBC demonstrates significant anti-inflammatory activity, outperforming standard drug molecules, and exhibits concentration-dependent effects. In an α-amylase inhibitory assay, a vital enzyme in the digestive process related to diabetes, SBC shows remarkable inhibition, surpassing standard drug performance, especially at higher concentrations. Molecular docking studies suggest the compound's potential interactions with enzymes responsible for inflammation and diabetes. SBC displays strong binding energies and inhibition constants with α-amylase, indicating its suitability for diabetes-related studies. The synthesis and characterization of SBC, combined with its excellent anti-inflammatory and anti-diabetic activities, underscore its potential as a promising candidate for further biomedical research and therapeutic development.

Metrological evaluation of facade coating systems regarding their resistance to microorganism growth

The presence of liquid water on the facade surface significantly contributes to the growth of microorganisms. This issue has become increasingly important with the growing use of thermal insulation in buildings. However, the formation of condensation on these façades is often increased due to low surface temperatures. Therefore, innovative coating systems with special physical parameters have been developed to prevent condensation formation and thus the growth of algae on the facade surface. These coatings should be evaluated with respect to their surface condensation to identify their resistance against condensation. Since no suitable method is available for this purpose, it is necessary to develop a method for controlling the wetness and drying out of façades. This paper presents the development and verification of innovative coating systems, as well as an active facade moisture detection system (ONE). The measuring method is designed to provide long-term non-destructive measurements of surface wetness. The measurement data obtained in this research are used to develop facade materials and coatings that improve their drying properties and the balance between hydrophilic and hydrophobic surfaces. This is aimed at preventing or reducing algae growth on the façade. A case study consisting of four test walls was conducted in Central Germany under real climate conditions to examine the resistance of coating systems with different pigments (conventional and modified pigments) to moisture formation on the surface. The results show that the developed coating system has significant potential to increase surface temperatures, leading to a reduced deviation of the dew point. This can help to prevent the growth of algae on the facade.

Investigating impacts of condensation on thermal performance in greenhouse glazing and operational energy use for sustainable agriculture

Condensation frequently manifests in environmentally controlled agricultural structures (such as greenhouses) due to the utilisation of specific covering materials and the often meticulous management of high relative humidity to facilitate optimal plant growth. The formation of condensation can significantly influence the thermal and optical characteristics of the covering materials, which also affects the covering insulation and the growth of plants. This study was conducted to investigate the impacts of surface condensation on the thermal performance of various greenhouse covering types. These options feature low-emissivity (Low-E) coatings, infrared reflective (IR) additives, UV protective films, and anti-condensation additives. The physical properties, specifically emissivity and wettability, were examined to understand their roles in modifying the thermal transfer dynamics of greenhouse coverings. A scale physical model was made to test the thermal performance of the coverings with and without condensation. The results indicated the effect of condensation on the overall heat transfer coefficient (U-factor). Especially when the surface exhibited characteristics of low emissivity, it resulted in a notable near-tripling of the U-factor. These widely accepted and advocated strategies of Low-E and IR reflective products may inadvertently lead to enhanced operational energy consumption when considering the influence of condensation. Notably, this research has also devised a regression function that establishes a correlation between the contact angle and the condensation heat transfer coefficient. This tool facilitates swift analysis and estimation of the effects of condensation on the U-factor. In the end, the potential and future work on condensation effects is also discussed.