Search Results (217)

Non-invasive, in vivo assessment of target substances penetration into the skin remains a significant challenge in dermatology and cosmetology. While various optical methods have been employed for this purpose, each has inherent limitations. Here, we present a novel non-invasive imaging approach using optical coherence elastography (OCE) to simultaneously determine the penetration depth of topically applied osmotically active substances in biological objects and associated water content changes with high sensitivity. Most substances are osmotically active and generate osmotic pressure proportional to their concentration, inducing deformations in biological objects. These osmotic strains can be visualized similarly to mechanical or thermal strains. Using OCE, we evaluated penetration and dehydration depth profiles in polyacrylamide gel phantoms, ex vivo cartilage, and porcine ear skin samples treated with aqueous glycerol solutions of varying concentrations. Additionally, the penetration and effect of jojoba oil were assessed in treated skin samples. The results are consistent with those obtained by other established methods, confirming the reliability and applicability of OCE. This technique offers unique capabilities not achievable with other optical methods, making it a valuable complementary tool for non-invasive studies. It holds significant promise for advancing both research and clinical applications in dermatology and cosmetology, including its potential translation to in vivo assessments. Full article

Background: Liuwei Dihuang Pills, a classic traditional Chinese medicine formula, has been widely used in clinical practice for its multiple pharmacological effects. However, the systematic characterization and identification of its chemical constituents, especially the aqueous decoction, remain insufficient, which hinders in-depth research on its pharmacodynamic material basis. Thus, there is an urgent need for a comprehensive analysis of its chemical components using advanced analytical techniques. Methods: After screening chromatographic columns, the ACQUITY UPLC™ HSS T3 column (100 mm × 2.1 mm, 1.8 μm) was selected. The column temperature was set to 40 °C, and the mobile phase consisted of 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B). A gradient elution program was adopted, and the separation was completed within 20 min. Ultra-high performance liquid chromatography–Orbitrap mass spectrometry (UPLC-Orbitrap-MS) combined with a self-established information database was used for the analysis. Results: A total of 80 compounds were tentatively identified, including 13 monoterpenoids, 6 phenolic acids, 16 iridoids, 11 flavonoids, 25 triterpenoids, and 9 other types. Triterpenoids are mainly derived from Poria cocos and Alisma orientale; iridoids are mainly from Rehmannia glutinosa; monoterpenoids are mainly from Moutan Cortex; and flavonoids are mainly from Dioscorea opposita. Among them, monoterpenoids, iridoids, and triterpenoids are important pharmacodynamic components. The cleavage pathways of typical compounds (such as pachymic acid, catalpol, oxidized paeoniflorin, and puerarin) are clear, and their mass spectral fragment characteristics are consistent with the literature reports. Conclusions: Through UPLC-Orbitrap-MS technology and systematic optimization of conditions, this study significantly improved the coverage of chemical component identification in Liuwei Dihuang Pills, providing a comprehensive reference for the research on its pharmacodynamic substances. However, challenges remain in the identification of trace components and isomers. In the future, analytical methods will be further improved by combining technologies such as ion mobility mass spectrometry or multi-dimensional liquid chromatography. Full article

Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) are powerful techniques that have been employed to analyze foodstuffs comprehensively. These techniques offer in-depth information about the chemical composition, structure, and spatial distribution of components in a variety of food products. Quantitative NMR is widely applied for precise quantification of metabolites, authentication of food products, and monitoring of food quality. Low-field ¹H-NMR relaxometry is an important technique for investigating the most abundant components of intact foodstuffs based on relaxation times and amplitude of the NMR signals. In particular, information on water compartments, diffusion, and movement can be obtained by detecting proton signals because of H₂O in foodstuffs. Saffron adulterations with calendula, safflower, turmeric, sandalwood, and tartrazine have been analyzed using benchtop NMR, an alternative to the high-field NMR approach. The fraudulent addition of Robusta to Arabica coffee was investigated by ¹H-NMR Spectroscopy and the marker of Robusta coffee can be detected in the ¹H-NMR spectrum. MRI images can be a reliable tool for appreciating morphological differences in vegetables and fruits. In kiwifruit, the effects of water loss and the states of water were investigated using MRI. It provides informative images regarding the spin density distribution of water molecules and the relationship between water and cellular tissues. ¹H-NMR spectra of aqueous extract of kiwifruits affected by elephantiasis show a higher number of small oligosaccharides than healthy fruits do. One of the frauds that has been detected in the olive oil sector reflects the addition of hazelnut oils to olive oils. However, using the NMR methodology, it is possible to distinguish the two types of oils, since, in hazelnut oils, linolenic fatty chains and squalene are absent, which is also indicated by the ¹H-NMR spectrum. NMR has been applied to detect milk adulterations, such as bovine milk being spiked with known levels of whey, urea, synthetic urine, and synthetic milk. In particular, T2 relaxation time has been found to be significantly affected by adulteration as it increases with adulterant percentage. The ¹H spectrum of honey samples from two botanical species shows the presence of signals due to the specific markers of two botanical species. NMR generates large datasets due to the complexity of food matrices and, to deal with this, chemometrics (multivariate analysis) can be applied to monitor the changes in the constituents of foodstuffs, assess the self-life, and determine the effects of storage conditions. Multivariate analysis could help in managing and interpreting complex NMR data by reducing dimensionality and identifying patterns. NMR spectroscopy followed by multivariate analysis can be channelized for evaluating the nutritional profile of food products by quantifying vitamins, sugars, fatty acids, amino acids, and other nutrients. In this review, we summarize the importance of NMR spectroscopy in chemical profiling and quality assessment of food products employing magnetic resonance technologies and multivariate statistical analysis. Full article

Aqueous solutions are not homogeneous and could be considered supramolecular systems. They can emit electromagnetic waves. Electromagnetic emission from one supramolecular system (“source”) can be received by another supramolecular system (“receiver”) without direct contact (distantly). This process represents a transfer of a “molecular signal” and causes changes in conformation and symmetry of the “receiver”. The aim of the current work is to theoretically describe such changes primarily using a solution of the chiral protein interferon-gamma (IFNγ) as an example. We provide theoretical evidence that supramolecular systems of highly diluted (HD) aqueous solutions formed by self-assembly after mechanical activation generate a stronger molecular signal compared to non-activated solutions, due to their higher energy-saturated state. Additionally, molecular signals cause supramolecular systems with complex (including chiral) structures to undergo easier changes in conformation and symmetry compared to simpler systems, enhancing their biological activity. Using statistical physics, we obtained the parameter Ic, characterizing the magnitude of conformational and symmetry changes in supramolecular (including chiral) systems caused by molecular signals. In quantum information science, there is an analogue of the parameter Ic, which characterizes the entanglement depth of quantum systems. This study contributes to the understanding of the physico-chemical basis of distant molecular interactions and opens up new possibilities for controlling the properties of complex biological and chemical systems. Full article

The equivalent conductivities of two aqueous silicate species, ${\left[\mathrm{SiO}{\left(\mathrm{OH}\right)}_3\right]}^{-}$ and ${\left[\mathrm{Si}{\mathrm{O}}_2{\left(\mathrm{OH}\right)}_2\right]}^{2-}$, are fundamental to understanding many physico-chemical phenomena of silicate materials in electrolyte solutions. These phenomena include diffusion, adsorption, and phase transformations. But significant inconsistencies have been presented in published equivalent conductivities of the two silicate aqueous ions. Also, little work has so far been undertaken to discuss how aspects, such as temperature and solution composition, may influence electrolytic conductivity of silicate aqueous solutions. This work presents the equivalent conductivities of the two silicate species, measured with electrochemical impedance spectroscopy (EIS) from 277.85 K to 308.45 K. A conductivity model for mixed electrolytes of high alkaline was first established. This model was then verified with the electrolyte conductivities of $\mathrm{NaOH}\text{-}{\mathrm{H}}_2\mathrm{O}$ solutions and $\mathrm{NaOH}\text{-}\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3\text{-}{\mathrm{H}}_2\mathrm{O}$ solutions. Next, the equivalent conductivities of ${\left[\mathrm{SiO}{\left(\mathrm{OH}\right)}_3\right]}^{-}$ and ${\left[\mathrm{Si}{\mathrm{O}}_2{\left(\mathrm{OH}\right)}_2\right]}^{2-}$, were calculated by solving the overdetermined equation groups for different temperatures, based on electrolyte conductivities of $\mathrm{NaOH}\text{-}\mathrm{N}{\mathrm{a}}_2\mathrm{Si}{\mathrm{O}}_3\text{-}{\mathrm{H}}_2\mathrm{O}$ solutions. The accuracy of both calculations and measurements are examined in depth from various viewpoints. This work presents essential inputs for quantitatively understanding multiple physico-chemical properties of silicate materials in electrolyte solutions. Full article

Background/Objectives: The role of the vitreous in the effective lens position (ELP) is controversial in patients undergoing phacovitrectomy. The aim of this study was to compare the change in aqueous depth (AD), a surrogate of the ELP, in non-vitrectomized and vitrectomized fellow eyes. Methods: Post-hoc analysis of a prospective study conducted in OMIQ facilities (Barcelona, Spain) between 2021 and 2023. Patients with bilateral cataracts and a unilateral grade 2/3 epiretinal membrane underwent phacoemulsification in one eye and phacovitrectomy without endotamponade in the fellow eye. All eyes were implanted with an extended depth-of-focus intraocular lens after power calculation using the same biometer, technicians, formula, and surgeon. We compared the change in AD (mm and percentage) from baseline, and the role of vitrectomy without endotamponade on AD with a mixed-effects models. Results: We included 40 eyes (20 patients) with a mean age of 71.6 years, with 55% females. The mean change in AD was +1.51 (vitrectomized) and +1.42 mm (non-vitrectomized eyes), p = 0.33. The percent of change in AD was not different between groups (p ≥ 0.38) and phacovitrectomy had no effect on the change in AD on mixed-effects models (p > 0.10). Conclusions: The absence of the vitreous had a minimal influence on AD in these patients undergoing standard phacoemulsification or phacovitrectomy. Full article

Amphibole-rich cumulates provide crucial information pertaining to the petrogenetic history of suprasubduction zone ophiolites and are, therefore, helpful in constraining the evolution and closure of the Neo-Tethys during the late Cretaceous to the early Tertiary period. Following this, the present contribution examines the meta-hornblendite and meta-hornblende-gabbro lithologies in the Mayudia ophiolite complex (MdOC), NE Himalaya, based on their field and petrographic relations, constituent mineral compositions, whole rock major and trace element chemistry and bulk strontium (Sr)—neodymium (Nd) isotope systematics. MdOC cumulates potentially represent the fossilized record of an island arc root, where amphibole + titanite + magnetite was fractionally crystallized from a super hydrous magma (10.56–13.61 wt.% melt water content) prior to plagioclase in a stable physico-chemical condition (T: 865–940 °C, P: 0.8–1.4 GPa, logfO₂: −8.59–−11.19 unit) at lower crustal depths (30–38 km). Such extreme hydrous nature in the parental magma was generated by the flux melting of the sub-arc mantle wedge with aqueous inputs from the dehydrating slab. A super hydrous magmatic reservoir was, therefore, extant at sub-arc mantle depths in the eastern Neo-Tethys, which has likely modulated the composition of the oceanic crust during intraoceanic subduction. Full article

Tensile tests of GW63K (Mg-6Gd-3Y-Zr) magnesium alloy under different heat treatment conditions were performed after immersion of the test specimens in 3.5 wt.% NaCl aqueous solution for periods up to 72 h. Results indicate that pitting corrosion should be responsible for the severe degradation of the tensile properties including yield strength, tensile strength (corrosion residual strength), and elongation within the testing time. The extreme depth of the corrosion pit was statistically related to corrosion residual strength. The variation of corrosion residual strength exhibited an exponential decay trend from 0 to 72 h. Furthermore, heat treatment enhanced the corrosion resistance of the GW63K alloy by inhibiting both the initiation and growth of corrosion pits, thereby improving the corrosion residual strength of the alloy. The critical working strength of GW63K alloy was significantly improved (increased to 192 MPa from 132 MPa) via heat treatment. Full article

Atmospheric aqueous-phase reactions have been recognized as an important source of secondary organic aerosols (SOAs). However, the unclear reaction kinetics and mechanics hinder the in-depth understanding of the SOA sources and formation processes. This study selected ten different substituted phenolic compounds (termed as PhCs) emitted from biomass burning as precursors, to investigate the kinetics using OH oxidation reactions under simulated sunlight. The factors influencing reaction rates were examined, and the contribution of reactive oxygen species (ROS) was evaluated through quenching and kinetic analysis experiments. The results showed that the pseudo-first-order rate constants (k_obs) for the OH oxidation of phenolic compounds ranged from 1.03 × 10⁻⁴ to 7.85 × 10⁻⁴ s⁻¹ under simulated sunlight irradiation with an initial H₂O₂ concentration of 3 mM. Precursors with electron-donating groups (-OH, -OCH₃, -CH₃, etc.) exhibited higher electrophilic radical reactivity due to the enhanced electron density of the benzene ring, leading to higher reaction rates than those with electron-withdrawing groups (-NO₂, -CHO, -COOH). At pH 2, the second-order reaction rate (k_{PhCs, OH}) was lower than at pH 5. However, the k_obs did not show dependence on pH. The presence of O₂ facilitated substituted phenols’ photodecay. Inorganic salts and transition metal ions exhibited varying effects on reaction rates. Specifically, NO₃⁻ and Cu²⁺ promoted k_{PhCs, OH}, Cl⁻ significantly enhanced the reaction at pH 2, while SO₄²⁻ inhibited the reaction. The k_{PhCs, OH} were determined to be in the range of 10⁹~10¹⁰ L mol⁻¹ s⁻¹ via the bimolecular rate method, and a modest relationship with their oxidation potential was found. Additionally, multiple substituents can suppress the reactivity of phenolic compounds toward •OH based on Hammett plots. Quenching experiments revealed that •OH played a dominant role in phenolic compound degradation (exceeding 65%). Electron paramagnetic resonance confirmed the generation of singlet oxygen (¹O₂) in the system, and probe-based quantification further explored the concentrations of •OH and ¹O₂ in the system. Based on reaction rates and concentrations, the atmospheric aqueous-phase lifetimes of phenolic compounds were estimated, providing valuable insights for expanding atmospheric kinetic databases and understanding the chemical transformation and persistence of phenolic substances in the atmosphere. Full article

The formation of aqueous pores through the interaction of amphipathic peptides is a process facilitated by the conformational dynamics typical of these biomolecules. Prior to their insertion with the membrane, these peptides go through several conformational states until they finally reach a stable α-helical structure. The conformational dynamics of these pore-forming peptides, α-PFP, is, thus, encoded in their amino acid sequence, which also predetermines their intrinsic flexibility. However, although the role of flexibility is widely recognized as fundamental in their bioactivity, it is still unclear whether this parameter is indeed decisive, as there are reports favoring the view of highly disruptive flexible peptides and others where relative rigidity also predetermines high rates of permeability across membranes. In this review we discuss in depth all those aspects linked to the conformational dynamics of these small biomolecules and which depend on the composition, sequence and dynamic performance both in aqueous phase and in close interaction with phospholipids. In addition, evidence is provided for the contribution of the known carboxyamidation in some well-studied α-PFPs, which are preferentially associated with sequences intrinsically more rigid than those not amidated and generally more flexible than the former. Taken together, this information is of great relevance for the optimization of new antibiotic peptides. Full article

Polyacrylonitrile (PAN) is renowned for its excellent physical and chemical properties, making it a promising candidate for producing high-performance and energetic materials. However, traditional high-molecular-weight PAN suffers from poor solubility and low reactivity, which limits its application as a precursor for advanced materials. To overcome these issues, this study successfully synthesized low-molecular-weight PAN (M_η: 6.808 kDa) using an environmentally friendly aqueous precipitation polymerization method, utilizing ammonium persulfate (6 wt% relative to the monomer mass) as the initiator and isopropanol (400 wt%) as the chain transfer agent. The structures and properties of the synthesized low-molecular-weight PAN were analyzed in depth. The morphology and chain structure of PAN were characterized using field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance hydrogen spectroscopy (¹H NMR). The thermal properties were assessed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Additionally, the state changes during the heating process of PAN with different molecular weights were directly observed using a visual melting point analyzer for the first time. Furthermore, the influence of molecular weight on PAN’s solubility was investigated in detail. Based on that, a linear regression between the viscosity average molecular weight (M_η) and the number average molecular weight (M_n) was established, providing simple and rapid access to the molecular weight of the synthesized PAN via viscosity measurements. Our study employed CTA-controlled aqueous precipitation polymerization to prepare low-molecular-weight PAN, which possesses significant potential in producing tetrazole-based energetic materials. Full article

With the continuous growth of global energy demand, the exploitation of deepwater oil and gas resources has become an important part of national energy strategies. The high-viscosity crude oil in deepwater areas such as the South China Sea poses severe challenges to oil and gas pipeline transportation due to its high pour point and high viscosity characteristics. Wax deposition, particularly significant under low temperature and high viscosity conditions, can lead to reduced pipeline flow rates, decreased transportation efficiency, and even potential safety hazards. Therefore, in-depth research on the wax deposition characteristics and mechanisms in high-viscosity systems holds significant theoretical and engineering application value. Current research primarily focuses on the influencing factors of wax deposition, deposition mechanisms, and the establishment of prediction models. Studies have shown that external factors such as temperature, shear intensity, operating time, and water content have significant effects on the wax deposition process. Specifically, increased temperature differences accelerate the deposition of wax molecules, while the presence of the aqueous phase inhibits wax crystallization and deposition. Furthermore, the formation mechanisms of wax deposition mainly include molecular diffusion, shear stripping, and aging effects. Researchers have explored the dynamic changes and influencing laws of wax deposition by establishing mathematical models combined with experimental data. In summary, although some progress has been made in studying the wax deposition characteristics in high-viscosity systems, research on wax deposition characteristics in mixtures, especially under the combined action of pour point depressants and flow improvers, is still inadequate. Future research should strengthen the systematic exploration of wax deposition mechanisms, quantify the effects of different external factors, and develop wax deposition prediction models suitable for practical engineering to ensure the safe and stable operation of deepwater oil and gas pipelines. Through in depth theoretical and experimental research, robust technical support can be provided for the efficient development of deepwater oil and gas resources. Full article

Copolymers of N-isopropylacrylamide (NIPA) and alkyl acrylic acids that swell and shrink in response to pH were prepared by dispersion polymerization at 35 °C using N-isopropylacrylamide (transduction monomer), methylenebisacrylamide (crosslinker), 2-dimethoxy-2-phenyl-acetophenone (initiator), N-tert-butylacrylamide (transition temperature modifier), and acrylic acid, methacrylic acid, ethacrylic acid, and propacrylic acid (functional comonomer). The diameter of the microspheres of the copolymer varied between 0.5 µm and 1.0 µm. These microspheres were cast into hydrogel membranes prepared by mixing the pH-sensitive swellable polymer particles with aqueous polyvinyl alcohol solutions followed by crosslinking the polyvinyl alcohol with glutaric dialdehyde for use as pH sensors. Large changes in the turbidity of the polyvinyl alcohol membrane monitored using a Cary 6000 UV–visible absorbance spectrometer were observed as the pH of the buffer solution in contact with the membrane was varied. Polymer swelling was reversible for many of these NIPA-based copolymers. The buffer capacity, ionic strength, pH, and temperature of the buffer solution in contact with the membrane were systematically varied to provide an in-depth pH profile of each copolymer. A unique aspect of this study was the investigation of the response of the NIPA-based polymers to changes in the pH of the solution in contact with the membrane at low buffer concentrations (0.5 mM). The response rate and the reversibility of polymer swelling even at low buffer capacity suggest that NIPA-based copolymers can be coupled to an optical fiber for pH sensing in the environment. We envision using these polymers to monitor rising acidity levels in the ocean due to water that has become enriched in carbon dioxide that endangers shell-building organisms by reducing the amount of carbonate available to them. Full article

Cancer is considered as the second leading cause of death worldwide. Chemotherapy, radiotherapy, immunotherapy, and targeted drug delivery are the main treatment options for treating cancers. Chemotherapy drugs are either available for oral or parenteral use. Oral chemotherapy, also known as chemotherapy at home, is more likely to improve patient compliance and convenience. Oral anti-cancer drugs have bioavailability issues associated with lower aqueous solubility, first-pass metabolism, poor intestinal permeability and drug absorption, and degradation of the drug throughout its journey in the gastrointestinal tract. A highly developed carrier system known as lipid polymer hybrid nanoparticles (LPHNs) has been introduced. These nanocarriers enhance drug stability, solubility, and absorption, and reduce first-pass metabolism. Consequently, this will have a positive impact on oral bioavailability enhancement. This article provides an in-depth analysis of LPHNs as a novel drug delivery system for anti-cancer agents. It discusses an overview of the limited bioavailability of anti-cancer drugs, their reasons and consequences, LPHNs based anti-cancer drug delivery, conventional and modern preparation methods as well as their drug loading and entrapment efficiencies. In addition, this article also gives an insight into the mechanistic approach to oral bioavailability enhancement, potential applications in anti-cancer drug delivery, limitations, and future prospects of LPHNs in anti-cancer drug delivery. Full article

Dual isotopes of sulfate (δ³⁴S_SO4 and δ¹⁸O_SO4), along with isotopes in water and trace elements of geothermal waters, are systematically investigated to quantitatively elucidate sulfate sources and oxygen and sulfur isotopic behaviors during deep groundwater circulation and to constrain reservoir temperatures in the Jimo nonvolcanic geothermal system on the eastern coast of China. The results show that δ³⁴S_SO4 and δ¹⁸O_SO4 values in geothermal waters ranged from −21.0 to 5.7‰ and from 1.1 to 8.8‰, respectively. An increase in SO₄ concentrations (140–796 mg/L) with a systematic decrease in δ³⁴S_SO4 and δ¹⁸O_SO4 values was observed along the flow path from the central to eastern and western parts. The sulfate in the Middle Group was predominantly from atmospheric deposition, with sulfide oxidation contributions of <27%. In contrast, 80–85% of SO₄ in the Eastern Group is derived from pyrite oxidation. In the Western Group, the oxidation of multiple metal sulfides contributed 43–66% of SO₄. Sulfate oxidation and mixing of shallow groundwater caused reservoir temperatures to be underestimated by 9 ± 6–14 ± 16% using silica and K-Mg geothermometers but overestimated by up to 52–62% using sulfate–water oxygen isotope geothermometers. The estimated average target reservoir temperature was 144 ± 8 °C, with geothermal waters circulating to depths of 3.6–4.6 km. This study offers new insights into the significant impact of sulfate-related processes on geothermometric estimates, a factor often overlooked when using aqueous geothermometers. It also provides valuable guidance for accurately estimating target geothermal reservoir temperatures and advancing exploration in nonvolcanic geothermal systems. Full article