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Recent heightened interest in inhaled bacteriophage (phage) therapy for combating antibacterial resistance in pulmonary infections has led to the development of phage powder formulations. Although phages have been successfully bioengineered into inhalable powders with preserved bioactivity, the stabilization mechanism is yet unknown. This paper reports the first study investigating the stabilization mechanism for phages in these powders. Proteins and other biologics are known to be preserved in dry state within a glassy sugar matrix at storage temperatures (Ts) at least ~50°C below the glass transition temperature (Tg). This is because at (Tg − Ts) >50°C, molecules are sufficiently immobilized with reduced reactivity. We hypothesized that this glass stabilization mechanism may also be applicable to phages comprising mostly of proteins. In this study, spray dried powders of Pseudomonas phage PEV20 containing lactose and leucine as excipients were stored at 5, 25 or 50°C and 15 or 33% relative humidity (RH), followed by assessment of bioactivity (PEV20 stability) and physical properties. PEV20 was stable with negligible titer loss after storage at 5°C/15% RH for 250 days, while storage at 33% RH caused increased titer losses of 1 log10 and 3 log10 at 5 and 25°C, respectively. The plasticizing effect of water at 33% RH lowered the Tg by 30°C, thus narrowing the gap between Ts and Tg to 19–28°C, which was insufficient for glass stabilization. In contrast, the (Tg − Ts) values were higher (range, 46–65°C) under the drier condition of 15% RH, resulting in the improved stability which corroborated with the vitrification hypothesis. Furthermore, phage remained stable (≤1 log10) when the (Tg − Ts) value lay between 26–48°C, but became inactivated as the value fell below 20°C. In conclusion, this study demonstrated that phage can be sufficiently stabilized in spray dried powders by keeping the (Tg − Ts) value above 46°C, thus supporting the vitrification hypothesis that phages are stabilized by immobilization inside a rigid glassy sugar matrix. These findings provide a guide to better manufacture and storage practices of inhaled phage powder products using for translational medicines.

We performed electrical conductivity measurements of rhyolite glasses across the glass transition temperature at 1 GPa. Our experimental data show that, in the Arrhenius plot, the conductivity of rhyolite with 0.2 wt% H 2 O has an inflection point between around 760 K, while for rhyolite with 4.9 wt% H 2 O the gradient changes between 685 and 825 K. These inflection points correlate with the glass transition temperature, and are compared with results of previous experiments. The degree of welding of clastic and hydrous rock can be constrained by estimating glass transition temperatures of volcanic rocks combined with measurements of electrical conductivity structures obtained from electromagnetic soundings beneath volcanic bodies. This, in turn, can be used to aid predictions of volcanic eruption. Graphical abstract

Epoxy resins (EPs) are crucial for high‐performance applications like lightweight materials, due to their excellent properties. However, the commonly used diglycidyl ether of bisphenol A (DGEBA) has two major disadvantages: it is synthesized mainly from petrochemicals and includes the health concerning bisphenol A. Eugenol is a bio‐based aromatic compound that can be modified into di‐ or triglycidyl ether. Through investigations four monomers are obtained based on eugenol and crosslinked with two curing agents isophorone diamine and 4,4′‐diaminodiphenyl sulfone to compare the properties of the resulting EPs with references containing DGEBA. Using new synthesis routes, the bio‐content of the monomers can be increased up to 94 wt%. Intramolecular cyclization occurs if a hydroxy group is in ortho‐position to the glycidyl ether group. The crosslinking conditions of the bio‐based monomers are comparable to or lower than those of DGEBA. The eugenol‐based triglycidyl monomers exhibit very high glass transition temperatures of up to 271 °C, almost 50 °C above the reference value, which can enable their use for lightweight construction such as matrices for fiber‐reinforced plastics. The char content of all bio‐based EPs after pyrolysis is significantly higher in comparison to the references, which may have a favorable effect on fire resistance. Four eugenol‐based epoxy monomers with two or three epoxy groups are synthesized to produce epoxy resins with high bio‐content and high glass transition temperatures (Tgs). The obtained monomers are crosslinked with two common amine‐based curing agents and compared with samples made from diglycidyl ether of bisphenol A (DGEBA). High Tgs of up to 271 °C and up to 49 °C higher than using DGEBA are achieved.

The interfacial effect is one of the significant factors in the glass-transition temperature (Tg) of the polymeric thin film system, competing against the free surface effect. Herein, the Tgs of poly (methyl methacrylate) (PMMA) films with different thicknesses and substrates are studied by fluorescence measurements, focusing on the influence of interfacial effects on the Tgs. The strong interaction between PMMA and quartz substrate leads to increased Tgs with the decreased thickness of the film. The plasmonic silver substrate causes enhanced fluorescence intensity near the interface, resulting in the delayed reduction of the Tgs with the increasing film thickness. Moreover, as a proof of the interface-dependent Tgs, hydrogen bonds of PMMA/quartz and molecules orientation of PMMA/silver are explored by the Raman spectroscopy, and the interfacial interaction energy is calculated by the molecular dynamics simulation. In this study, we probe the inter-relationship between the interfacial interactions arising from the different substrates and the Tg behavior of polymer thin films.

Fast-curing polyurethane (PU) systems are attractive for high-throughput manufacturing, but quantifying cure kinetics, gelation, and cure-dependent glass transition temperature (Tg) is difficult, especially at a low degree of cure (DoC). Here, a fast-reacting BASF PU formulation was studied using non-isothermal differential scanning calorimetry (DSC) at multiple heating rates, rheometry at 50 °C, and molecular dynamics (MD) simulations to extend Tgα in the low-DoC regime. DSC provided reaction enthalpy and conversion histories, and Kamal–Sourour (KS) parameters were identified by robust nonlinear fitting, reproducing conversion and curing rate profiles (R2 > 0.99 and >0.95). Rheology indicated gelation between 475 and 625 s (DoC ≈ 0.53), and DSC-based Tg at uncured, gelation, and fully cured states, established the experimental Tg trend. MD (LAMMPS) with topological crosslinking and NPT thermal scans extracted Tg from density–temperature slopes at selected DoC points. Experimental and MD Tg data were fused with Gaussian process regression constrained by the DiBenedetto relationship (5-fold cross-validation), giving λ ≈ 0.29 and confidence intervals. This framework links kinetics, gelation, and Tg evolution for fast-curing PU and identifies the low-DoC region as the main source of uncertainty.

This study investigated the evolution of mass-exchange, physicochemical, mechanical, thermal, and structural properties of meat analog (MA)-based batter-coated parfried food. Wheat and rice flour–based batter systems were used to coat the MA. Parfried (at 180 °C for 60 s) MA were frozen at − 18 °C, − 76 °C, and liquid N2 and stored at − 18 °C for up to 6 months. Parfried MA were finish-fried at 180 °C for 180 s and their attributes were studied. Results reveal that batter formulation and freezing considerably impact the moisture-fat profile as well as textural attributes (hardness, brittleness, crispiness) of finish-fry–coated MA. The color of finish-fry–coated MA is batter formulation–dependent and different than parfried MA. Freezing at − 76 °C slowed quality deterioration of parfried MA in comparison to freezing at − 18 °C. Compared to low-moisture–containing parfried MA, high-moisture–containing coated parfried MA are greatly affected by the freezing process and frozen storage. Storage loss (SL, %) of coated parfried MA increased with the duration of frozen storage, and SL is greatly impacted by batter formulation. Frozen storage duration of parfry-coated MA is negatively correlated with the moisture content of finish-fried MA. Storage duration is positively correlated with fat content and hardness of finish-fried MA. Batter formulation impacted glass-transition temperature (Tg) of parfried MA, that consequently affected their frozen storage quality and finish-frying behavior. Scanning electron microscopy provided mechanistic insights in understanding the impacts of batter formulation and freezing rates on microstructural attributes and consequentially quality evolution of MA-based coated product.

A rapid increase in viscosity during the polymerization process impacts the polymerization rate. To address this issue, ethylbenzene is often introduced into the polymerization system in order to reduce viscosity. The thermal characteristics of styrene–ethylbenzene polymerization have been identified using differential scanning calorimetry. The rate of heat generation significantly decreases as the proportion of ethylbenzene increases. The polymerization product mixtures were analyzed using gel permeation chromatography. Polymerization at low viscosity yields a higher proportion of low molecular mass polymers and a more uniform distribution of product chain lengths compared to polymerization at high viscosities. The glass transition temperature and the activation energy for viscous flow of the products were also determined. The apparent kinetics of styrene polymerization may be described using the “autocatalytic + Nth-order” model. Two stages of monomer conversion are apparent: polymerization reactions initiated by AIBN and thermally induced polymerization. Valuable insights into the polymerization process which can contribute to the optimization of industrial polymerization reactions have been obtained.

The rational design of polyimides (PIs) with targeted glass transition temperature ( ) is crucial for advanced microelectronics applications. While data-driven approaches offer promise, there is a pressing need for models that are not only predictive but also physically interpretable, especially with limited datasets. Herein, we present a highly interpretable Quantitative Structure-Property Relationship (QSPR) model for accurate prediction of PIs. Employing a Genetic Algorithm combined with Multiple Linear Regression (GA-MLR), we identified an optimal set of seven molecular descriptors from a curated dataset. The model demonstrates robust predictive performance and strong generalization ability, validated through rigorous statistical tests. Crucially, we provide a deep physicochemical interpretation of the descriptors, unifying their influence under the framework of free volume theory. We show that key descriptors govern by modulating the fractional free volume through distinct mechanisms: descriptors like Chi0n increase free volume by introducing molecular branching that disrupts chain packing, while MinPartialCharge influences through its effect on intermolecular interactions. This mechanistic understanding is translated into clear molecular design guidelines, distinguishing strategies for achieving high- versus processable, low- polymers. Our work establishes a reliable and transparent computational tool that bridges data-driven prediction with fundamental chemical insight for accelerating PIs development.

A new series of colorless polyimides (CPIs) with outstanding thermal properties and mechanical properties were fabricated by the copolymerization of a novel dianhydride and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2′-bistrifluoromethyl benzidine (TFDB). The novel dianhydride, 10-oxo-9-phenyl-9-(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetraacid dianhydride (3FPODA), possessed a rigid semi-alicyclic structure, –CF3 and phenyl side groups, and an active carbonyl group. Benefitting from the special structure of 3FPODA, the glass transition temperatures (Tg) of the new CPIs improved from 330 °C to 377 °C, the coefficient of thermal expansion (CTE) decreased from 46 ppm/K to 24 ppm/K, and the tensile strength (TS), tensile modulus (TM), and elongation at break (EB) increased from 84 MPa to 136 MPa, 3.2 GPa to 4.4 GPa, and 2.94% to 4.13% with the increasing amount of 3FPODA, respectively. Moreover, the active carbonyl group of the 3FPODA could enhance the CPI’s adhesive properties. These results render the new dianhydride 3FPODA an ideal candidate monomer for the fabrication of high-performance CPIs.

Monitoring of molding processes is one of the most challenging future tasks in polymer processing. In this work, the in situ monitoring of the curing behavior of highly filled EMCs (silica filler content ranging from 73 to 83 wt%) and the effect of filler load on curing kinetics are investigated. Kinetic modelling using the Friedman approach was applied using real-time process data obtained from in situ DEA measurements, and these online kinetic models were compared with curing analysis data obtained from offline DSC measurements. For an autocatalytic fast-reacting material to be processed above the glass transition temperature Tg and for an autocatalytic slow-reacting material to be processed below Tg, time–temperature–transformation (TTT) diagrams were generated to investigate the reaction behavior regarding Tg progression. Incorporating a material containing a lower silica filler content of 10 wt% enabled analysis of the effects of filler content on sensor sensitivity and curing kinetics. Lower silica particle content (and a larger fraction of organic resin, respectively) favored reaction kinetics, resulting in a faster reaction towards Tg1. Kinetic analysis using DEA and DSC facilitated the development of highly accurate prediction models using the Friedman model-free approach. Lower silica particle content resulted in enhanced sensitivity of the analytical method, leading, in turn, to more precise prediction models for the degree of cure.