Search Results (28)

Dual-layer membranes can offer significant advantages in desalination via membrane distillation (MD) compared to conventional single-layer designs. In this study, we report the development of a novel dual-layer nylon/polyvinylidene fluoride (PVDF) membrane with a Janus architecture, specifically engineered for application in sweeping gas membrane distillation (SGMD). The non-solvent induced phase separation (NIPS) method was used to cast PVDF solution on the top of a commercial nylon membrane. Water contact angle (WCA) measurements showed asymmetrical wettability. Scanning electron microscopy (SEM) confirmed that the PVDF layer was firmly anchored to the nylon support without signs of delamination. Desalination experiments were conducted using SGMD, where a significant flux enhancement as high as 81.2% was observed when the feed solution contacted the hydrophilic nylon surface while the hydrophobic PVDF surface faced the permeate side with gas flow. This enhancement was attributed to the high partitioning coefficient of the liquid–vapor mixture on the hydrophilic feed surface and the rapid vapor release across the hydrophobic permeate surface. Overall, these results demonstrate that hydrophilic membranes with small pore sizes (i.e., 0.22 µm) can serve effectively as supports when fabricated using the NIPS process, enabling new configurations for high-performance SGMD. Full article

The development of energy-efficient separation technologies for nitrogen (N₂)–hydrogen (H₂) mixtures under conventional industrial conditions remains a critical challenge. Adsorptive separation emerges as a promising strategy, contingent upon the design of high-performance adsorbents with tailored physicochemical properties. In this study, three isoreticular zirconium-based metal–organic frameworks (UiO-66, UiO-66-CH=CH₂, and UiO-66-F₄) are systematically evaluated for the purification of industrial N₂-H₂ mixed gases. By integrating static adsorption isotherms, dynamic breakthrough experiments, and molecular dynamics (MD) simulations, we comprehensively characterize the adsorption mechanisms and diffusion kinetics. The results demonstrate that UiO-66-F₄ exhibits optimal performance in capturing N₂ from N₂-H₂ mixtures under simulated industrial conditions, owing to its balanced binding affinity, high nitrogen uptake, and favorable micro-/mesoporous diffusion dynamics. This work offers a promising alternative for N₂-H₂ separation in industrial applications. Full article

Background/Objectives: The development of dry powder formulations for pulmonary delivery of therapeutic antibodies requires careful stabilization strategies to preserve protein integrity during spray-drying and long-term storage. This study investigates the impact of various sugar-derivatives, a polyol (D-mannitol), a disaccharide (D-sucrose) and a polysaccharide (dextran 10 kDa), used individually or in combination, on the physical stability of bovine polyclonal immunoglobulin G (pAb) in dry powders for inhalation (DPIs). Methods: A design of experiments (DoE) approach was employed to evaluate the effects of these excipients on residual moisture (RM), low-order aggregates (LOA) and high-order aggregates (HOA), immediately after spray-drying (T0) and after 10 months of storage at room temperature in a desiccator (T10). Results: All DPIs exhibited a high amorphous content and a favorable glass transition temperature, with RM decreasing over time. The combination of D-mannitol and dextran 10 kDA (DPI-MD) demonstrated the most effective stabilization, minimizing LOA and HOA formation at T0 and T10. Although the ternary mixture, including D-sucrose (DPI-MSD) exhibited higher process stability, it was less stable over time in comparison to the binary mixture. The aerodynamic performance of these carrier-free DPIs, assessed via laser diffraction (% ˂ 5 µm), were between 51 ± 3 (DPI-MD) and 67 ± 4 (DPI MSD) and a Next Generation Impactor, confirmed that formulation produced aerosol with suitable size distribution and fine particle fractions (FPFn upt to 71 ± 5% for DPI-MSD), for deep pulmonary deposition. Conclusions: These findings highlight the importance of combining excipients with complementary physical properties to achieve robust protein stabilization. The DPI-MD emerged as the most promising candidate for pAb lung delivery, balancing protein integrity, powder stability, and aerodynamic efficiency. Full article

Understanding how pore-system geometry governs mechanical performance remains essential for designing slag-blended cementitious materials. This study investigates the time-dependent coupling between porosity P and fractal dimension D and its implications for strength development and brittleness evolution in cementitious materials with slag dosage variation (0–40%). Compressive strength (f_c), flexural strength (f_f), the compressive-to-flexural strength ratio (f_c/f_f, used as a practical brittleness proxy), porosity (%), fractal dimension, and low-field nuclear magnetic resonance (LF-NMR) permeability (k, mD) were evaluated at 3, 7, and 28 days. Results reveal a pronounced age dependence in microstructure–property relationships. At 28 days, increasing slag dosage led to monotonic pore refinement and geometric reorganization, evidenced by reduced porosity (4.84% → 3.88%), increased fractal dimension (2.754 → 2.820), and decreased permeability (0.00025 → 0.00011 mD), accompanied by enhanced mechanical performance (47.73 → 49.33 MPa in f_c; 6.34 → 7.11 MPa in f_f) and reduced brittleness (f_c/f_f: 7.53 → 6.94). In contrast, a critical 7-day decoupling was observed: slag mixtures exhibited substantially lower porosity (≈5.42–5.69% vs. 7.07% for the reference) yet lower compressive strength (≈34.81–35.29 MPa vs. 38.65 MPa), indicating that porosity alone is insufficient to interpret early-age compressive capacity. Across ages, permeability and fractal trends highlight the role of pore-network connectivity and geometric complexity in governing transport resistance and fracture-related behavior. Overall, the findings demonstrate that a time-dependent porosity–fractal coupling framework provides a coherent pathway “from pore geometry to strength,” particularly for brittleness-relevant indices where geometric effects are amplified. Full article

This study presents an enantiomeric-ratio-driven strategy for constructing mechanically robust supramolecular gels using cyclohexane bisurea derivatives. By employing non-equimolar enantiomeric mixtures, we achieved an ultralow critical gelation concentration (CGC < 2 mg/mL) in toluene, representing a reduction of more than fivefold compared to homochiral single-enantiomer systems. Rheological measurements revealed substantially enhanced mechanical properties in the non-equimolar gels, with yield stress and storage modulus values up to 17 and 20 times higher, respectively, than those of single-enantiomer gels. Morphological analyses (SEM and POM) indicated that pure enantiomers form isolated crystalline fibers with limited connectivity, whereas racemic mixtures yield disordered amorphous aggregates. In contrast, non-equimolar mixtures self-assemble into hierarchical “sea urchin-like” architectures, wherein crystalline fibers radiate from central cores to form densely interconnected networks. This unique structural motif underpins both the ultralow CGC and superior mechanical performance. Complementary FT-IR, XRD, and DSC analyses demonstrated that chiral imbalance modulates hydrogen-bonding interactions and structural order, while molecular dynamics (MD) simulations provided insight into the divergent self-assembly pathways among homochiral, racemic, and non-equimolar systems. This work provides a stereochemically guided approach for designing high-performance supramolecular gels with tailored hierarchical structures and enhanced functionality. Full article

Each layer of the constructed asphalt pavement is evaluated by measuring its quality indicators, as specified in the construction regulations ĮT ASFALTAS 08, and comparing the obtained values with the corresponding design or threshold values. Due to inherent variability in material properties and systematic or random errors during the production, transport, and installation of the asphalt mixture, the quality indicators of the asphalt layers often deviate from their optimal values. When deviations exceed permissible deviations (PD) or limit values (LV), monetary deductions (MDs) are applied. This study presents normalised values and variation dynamics for 10 quality indicators of the asphalt layer subject to MDs in Lithuania. Using the expertise of 71 road construction professionals and multi-criteria decision-making (MCDM) methods, the influence of these deviations on road quality was assessed. The experts ranked all indicators using percentage weights and the Analytic Hierarchy Process (AHP) method. Expert consensus was verified using concordance coefficients and consistency ratios. After eight statistical outliers were excluded, adjusted weights were calculated based on responses from 63 experts. The proposed method, termed CIBRO (Criteria Importance But Rejected Outliers), enables the objective prioritisation of asphalt quality indicators. The CIBRO method enhances expert concordance and results reliability by aligning criterion ranks with the normal distribution, complementing the Kendall rank correlation approach. The findings highlight that insufficient compaction, inadequate layer thickness, and binder content deviations are the most influential factors that affect layer quality. In contrast, deviations in pavement width, friction coefficient, and surface evenness (measured with a 3 m straight edge) were found to have a lesser impact. The CIBRO method offers a robust approach to assessing the importance of the quality of the asphalt layer, supporting improvements in construction standards and pavement assessment systems. Full article

Compatibilizers play a critical role in resolving compatibility issues between styrene–butadiene–styrene (SBS) modifiers and asphalt systems. These additives enhance the uniform dispersion of SBS modifiers and stabilize their cross-linked network structure within the asphalt matrix. This study employed molecular dynamics (MD) simulations via Materials Studio (MS) to investigate the effects of a compatibilizer on compatibility mechanisms and diffusion behavior in SBS-modified asphalt (SBSMA). Model validation was conducted through density and glass transition temperature (Tg) analyses. The cohesive energy density (CED) and solubility parameters were quantified to assess the impact of compatibilizer dosage on system compatibility. Radial distribution function (RDF) and mean square displacement (MSD) analyses elucidated molecular diffusion dynamics. The results indicate that compatibilizers enhance cohesive energy density by 12.5%, suppress irregular intermolecular motion, and reduce system instability. The synergistic interaction between aromatic and saturated components in compatibilizers effectively disperses asphaltene aggregates and inhibits π–π stacking. Additionally, strong solubility interactions with hydrocarbon mixtures facilitate the diffusion of asphaltene gum molecules. These findings provide molecular-level insights for optimizing compatibilizer design in SBSMA applications. Full article

Tetrodotoxin (TTX), a potent Site-1 sodium channel blocker (S1SCB), offers highly effective local anesthetic properties with minimal addiction potential. To fully leverage TTX’s capabilities as a local anesthetic, it is crucial to develop a drug delivery system that balances its systemic toxicity with its therapeutic efficacy. Recent studies have shown that peptide mixtures, derived from fragments of Site-1 sodium channel proteins and enhanced with hydrophobic tails (designated MP1 and MP2), can self-assemble into nanostructures that exhibit remarkable sustained-release capabilities for TTX. Despite the profound impact that the addition of a hydrophobic tail has on altering the release behavior of the original peptides, the atomic-level interactions and mechanisms underlying this phenomenon remain poorly understood. In this study, a combination of ColabFold and molecular dynamics (MD) simulations were used to investigate the binding interactions between TTX and the nanostructures formed by MP1 and MP2 at an atomic level. Our findings agree with experimental observations and indicate that the MP1/MP2 nanostructure demonstrates greater stability and higher binding affinity for TTX compared to their non-modified counterparts, P1 and P2. The analysis of the simulations revealed that charged amino acids, specifically aspartic acid (ASP) and glutamic acid (GLU), on the peptides are crucial for strong TTX binding and serve as the primary functional sites. Additionally, the stability of the nanostructure significantly affects TTX binding affinity, elucidating why P1, P2, MP1, and MP2 exhibit different binding capabilities despite containing identical charged residues. The results reported here may provide fundamental information to drive future research and enhance the development of TTX-based drug delivery systems. Full article

The separation of oxygen (O₂) and nitrogen (N₂) from air is a process of utmost importance nowadays, as both species are vital for numerous fundamental processes essential for our development. Membranes designed for their selective molecule separation have become the materials of choice for researchers, primarily due to their ease of use. The present study proposes grazynes, 2D carbon-based materials consisting of sp and sp² C atoms, as suitable membranes for separating O₂ and N₂ from air. By combining static density functional theory (DFT) calculations with molecular dynamics (MD) simulations, we address this issue through a comprehensive examination of the thermodynamic, kinetic, and dynamic aspects of the molecular diffusions across the nano-engineered pores of grazynes. The studied grazyne structures have demonstrated the ability to physisorb both O₂ and N₂, preventing material saturation, with diffusion rates exceeding 1 s⁻¹ across a temperature range of 100–500 K. Moreover, they exhibit a selectivity of ca. 2 towards O₂ at 300 K. Indeed, MD simulations with equimolar mixtures of O₂:N₂ indicated a selectivity towards O₂ in both grazynes with ca. twice as many O₂ filtered molecules in the [1],[2]{2}-grazyne and with O₂ representing ca. 88% of the filtered gas in the [1],[2]{(0,0),2}-grazyne. [1],[2]{2}-grazyne shows higher permeability for both molecules compared to the other grazyne, with O₂ demonstrating particularly enhanced diffusion capacity across both membranes. Further MD simulations incorporating CO₂ and Ar confirm O₂ enrichment, particularly with [1],[2]{(0,0),2}-grazyne, which increased the presence of O₂ in the filtered mixture by 26% with no evidence of CO₂ molecules. Full article

By combining molecular dynamics (MD) simulations and density functional theory (DFT), the influence of dye structure on the optical modulation properties of negative-mode guest–host liquid crystal (GHLC) systems was systematically investigated. Firstly, the reliability of the simulation method was validated by comparing the performance parameters of the GHLC system obtained from simulations with those from experimental results. Subsequently, a series of guest dye molecules, along with their mixtures with negative dielectric anisotropy mesogens, were designed and analyzed. This exploration focused on how variations in dye terminal chain lengths, substitution positions, and substituent group properties affect dye molecular geometry, dye alignment within the host, transition dipole orientation, absorption spectra, and electronic excitation properties. Our findings suggest that dye molecules with a flexible terminal chain substitution of five carbon atoms, positioned at the 2 and 6 locations on the anthraquinone core, exhibit higher order parameters, favorable for enhancing dichroic performance. Moreover, introducing different α-substituents further influences the dye orientation and electronic behavior within the host. These results highlight that structural modifications of anthraquinone-based dyes allow for the design of high-dichroic-ratio materials with customized absorption properties. Overall, our results provide a beneficial understanding of the structure–property relation in GHLC systems, offering valuable guidance for designing high-performance dye molecules and advanced optoelectronic materials in future research. Full article

Molecular imprinting is a promising approach for developing polymeric materials as artificial receptors. However, only a few types of molecularly imprinted polymers (MIPs) are commercially available, and most research on MIP_S is still in the experimental phase. The significant limitation has been a challenge for screening imprinting systems, particularly for weak functional target molecules. Herein, a combined method of quantum mechanics (QM) computations and molecular dynamics (MD) simulations was employed to screen an appropriate 2,4-dichlorophenoxyacetic acid (2,4-D) imprinting system. QM calculations were performed using the Gaussian 09 software. MD simulations were conducted using the Gromacs2018.8 software suite. The QM computation results were consistent with those of the MD simulations. In the MD simulations, a realistic model of the ‘actual’ pre-polymerisation mixture was obtained by introducing numerous components in the simulations to thoroughly investigate all non-covalent interactions during imprinting. This study systematically examined MIP systems using computer simulations and established a theoretical prediction model for the affinity and selectivity of MIPs. The combined method of QM computations and MD simulations provides a robust foundation for the rational design of MIPs. Full article

Surfactants play a crucial role in tertiary oil recovery by reducing the interfacial tension between immiscible phases, altering surface wettability, and improving foam film stability. Oil reservoirs have high temperatures and high pressures, making it difficult and hazardous to conduct lab experiments. In this context, molecular dynamics (MD) simulation is a valuable tool for complementing experiments. It can effectively study the microscopic behaviors (such as diffusion, adsorption, and aggregation) of the surfactant molecules in the pore fluids and predict the thermodynamics and kinetics of these systems with a high degree of accuracy. MD simulation also overcomes the limitations of traditional experiments, which often lack the necessary temporal–spatial resolution. Comparing simulated results with experimental data can provide a comprehensive explanation from a microscopic standpoint. This article reviews the state-of-the-art MD simulations of surfactant adsorption and resulting interfacial properties at gas/oil–water interfaces. Initially, the article discusses interfacial properties and methods for evaluating surfactant-formed monolayers, considering variations in interfacial concentration, molecular structure of the surfactants, and synergistic effect of surfactant mixtures. Then, it covers methods for characterizing microstructure at various interfaces and the evolution process of the monolayers’ packing state as a function of interfacial concentration and the surfactants’ molecular structure. Next, it examines the interactions between surfactants and the aqueous phase, focusing on headgroup solvation and counterion condensation. Finally, it analyzes the influence of hydrophobic phase molecular composition on interactions between surfactants and the hydrophobic phase. This review deepened our understanding of the micro-level mechanisms of oil displacement by surfactants and is beneficial for screening and designing surfactants for oil field applications. Full article

The endo-1,4-β-xylanases (EC 3.2.1.8) are the largest group of hydrolytic enzymes that degrade xylan, the major component of hemicelluloses, by catalyzing the hydrolysis of glycosidic bonds β-1,4 in this polymer, releasing xylooligosaccharides of different sizes. Xylanases have considerable potential in producing bread, animal feed, food, beverages, xylitol, and bioethanol. The fungus Aspergillus tamarii Kita produced xylanases in Adams’ media supplemented with barley bagasse (brewer’s spent grains), a by-product from brewery industries. The culture extract exhibited two xylanase activities in the zymogram, identified by mass spectrometry as glycosyl hydrolase (GH) families 10 and 11 (GH 10 and GH 11). The central composite design (CCD) showed excellent predictive capacity for xylanase production (23.083 U mL⁻¹). Additionally, other enzyme activities took place during the submerged fermentation. Moreover, enzymatic saccharification based on a mixture design (MD) of three different lignocellulosic residues was helpful in the production of fermentable sugars by the A. tamarii Kita crude extract. Full article

In the conditions of an energy crisis, an important issue is the increase in energy efficiency and productivity of welding and hardfacing processes. The article substantiates the perspective of using exothermic additives introduced into core filler for flux-cored wire arc welding processes as a relatively cheap additional heat source, reducing energy consumption when melting filler materials, and increasing the deposition rate. The mixture design (MD) was selected as the design method to optimize the average values of current and voltage, as well as arc stability parameters depending on core filler composition. This article studies the influence of the introduction of exothermic addition (EA), as well as the ratios CuO/C and CuO/Al on arc stability for the FCAW S process. Parameters characterizing arc stability were determined using an oscillograph, and from the obtained oscillograms, an analysis was conducted on arc voltage and welding current signals during flux-cored arc welding. It was determined that various methods can be used to evaluate arc stability, which can be divided into two groups: graphical (current and voltage cyclograms, box plots with frequency histograms, ellipse parameters plotted on current, and voltage cyclograms) and statistical (standard variation and coefficients of variation for welding current and arc voltage). In this paper, a comprehensive evaluation of arc stability depending on the composition of the cored wire filler was carried out. It was determined that the most stable current parameters were observed for the flux-cored wire electrode with an average exothermic addition content at the level of EA = 26.5–28.58 wt.% and a high carbon content (low values of CuO/C = 3.75). Conversely, the lowest values of arc stability (CV(U) and Std(U)) were observed during hardfacing with a flux-cored wire electrode with a high CuO/Al ratio ≥ 4.5 and a content of exothermic addition in the core filler below the average EA < 29 wt.%. Mathematical models of mean values, standard deviation, coefficient of variation for welding current, and arc voltage were developed. The results indicated that the response surface prediction models had good accuracy and prediction ability. The developed mathematical models showed that the ratio of oxidizing agent to reducing agent in the composition of exothermic addition (CuO/Al) had the greatest influence on the welding current and arc voltage characteristics under investigation. The percentage of exothermic mixture in the core filler (EA) only affected the average welding current (Iaw) and the average arc voltage (U_aw). The graphite content expressed through the CuO/C ratio had a significant impact on welding current parameters as well as the coefficient of variation of arc voltage (CV(U)). Two welding parameters were selected for optimization: the mean welding current (I_aw) and the standard deviation of arc voltage (Std(U)). The best arc stability when using exothermic addition CuO-Al in the core filler was observed at CuO/Al = 3.6–3.9, CuO/C = 3.5–4.26, and at an average EA content of 29–38 wt.%. The significant influence of the CuO/Al and CuO/C ratios on arc voltage parameters can also be explained by their impact on the elemental composition of the welding arc (copper, cupric oxide (CuO), and Al₂O₃). The more complete this reaction, the higher the amount of easily vaporized copper (Cu) in the arc plasma, enhancing arc stability. The influence of core filler composition on the microstructure of deposited metal of the Fe-Cr-Cu-Ti alloy system was investigated. Full article

Deep eutectic solvents (DESs) have recently gained increased attention for their potential in biotechnological applications. DESs are binary mixtures often consisting of a hydrogen bond acceptor and a hydrogen bond donor, which allows for tailoring their properties for particular applications. If produced from sustainable resources, they can provide a greener alternative to many traditional organic solvents for usage in various applications (e.g., as reaction environment, crystallization agent, or storage medium). To navigate this large design space, it is crucial to comprehend the behavior of biomolecules (e.g., enzymes, proteins, cofactors, and DNA) in DESs and the impact of their individual components. Molecular dynamics (MD) simulations offer a powerful tool for understanding thermodynamic and transport processes at the atomic level and offer insights into their fundamental phenomena, which may not be accessible through experiments. While the experimental investigation of DESs for various biotechnological applications is well progressed, a thorough investigation of biomolecules in DESs via MD simulations has only gained popularity in recent years. Within this work, we aim to provide an overview of the current state of modeling biomolecules with MD simulations in DESs and discuss future directions with a focus for optimizing the molecular simulations and increasing our fundamental knowledge. Full article