UV Absorption Research Articles

Effect of Heavy Rainfalls on Natural Organic Matter and Trihalomethanes in Surface Water Sources

Storm events have a notable impact on natural organic matter (NOM) and trihalomethanes (THMs). Water samples were collected and analyzed from Ulutan Dam (UD), in the Zonguldak region, Turkey. During four storm events, the data indicated the presence of hysteresis patterns in three of the four storms, with elevated concentrations of organic constituents observed during the falling limb of the hydrographs. It was observed that a higher specific THM (sp.THM) concentration (201.83 µg/L) was reached with an average specific UV absorbance (SUVA) value of 6.66 L/mg·m in the fourth storm. This means that the primary sources of THM precursors are the aromatic compounds present in NOM. A significant correlation between UV absorbance (UV254) and dissolved organic carbon (DOC) (R = 0.99–0.92) for all storms was observed. Chlorine demand also yielded a strong correlation (R = 0.81–0.99) with UV254 and DOC. Therefore, the present study indicates that UV254 can be an effective parameter for monitoring applicable chlorine dosage in drinking water treatment management as faced with storm events. On the other hand, the results of the study also provide valuable insight into the direct and indirect link between short-term precipitation events and their impact on the structural and THM precursors in surface water sources.

Evaluation of Whitening Effects and Identification of Potentially Active Compounds Based on Untargeted Metabolomic Analysis in Different Chrysanthemum Cultivar Extracts

Chrysanthemum is a traditional Chinese medicinal herb. Chrysanthemum extracts are rich in bioactive compounds; however, there are few reports evaluating the whitening effects of organic chrysanthemum extracts. This study assessed the antioxidant and whitening effects of organic extracts from the petals of five chrysanthemum cultivars from Guangdong, China. Significant differences were observed among the five cultivars across various parameters, including IC50 values for tyrosinase inhibition activity, DPPH and ABTS values, UV absorption, and SPF values. Additionally, there were notable variations in total flavonoid, total phenolic, and chlorogenic acid contents. The BJ cultivar extract exhibited strong antioxidant capacity and superior whitening effects, containing the highest levels of total flavonoids, total phenolics, and chlorogenic acid. Correlation analysis indicated a significant relationship between total flavonoid content and IC50 of DPPH, and between chlorogenic acid and both IC50 of ABTS and SPF. Untargeted metabolomic analysis of three representative cultivars (BJ, WYHJ, and JSHJ) identified 22 compounds potentially related to antioxidant and whitening effects. Compounds significantly correlated with multiple antioxidant or whitening indicators (p < 0.05, r > 0.8) included tangeritin, hydroquinone, eupatilin, quercetin 3-(6″-malonyl-glucoside), biochanin A, and cyanidin 3-glucoside. These compounds may play crucial roles in the antioxidant and whitening effects of chrysanthemum extracts. The results highlight the promising antioxidant and whitening properties of chrysanthemum extracts, with certain genotypes, such as BJ, showing potential as superior raw material sources.

UV Resistance Properties of Lignin Influenced by Its Oxygen-Containing Groups Linked to Aromatic Rings.

The influence of lignin's primary oxygen-containing functional groups, phenolic OH (Ph-OH) and methoxyl (OMe) groups, especially the Ph-OH/OMe ratio, on its UV absorptivity and long-lasting UV blocking remains unclear. In this study, organosolv lignins (OLs) with varying Ph-OH and OMe contents were prepared to evaluate their UV absorptivity and photostability by EPR (electron paramagnetic resonance). As the Ph-OH contents increased from 0.32 to 6.09 mmol/g, lignin with a higher Ph-OH content displayed better absorptivity with a strong correlation (Pearson's r = 0.95). However, an excessive Ph-OH content (>5.5 mmol/g) reduced the spin content of lignin, negatively affecting its photostability. Taking Ph-OH and OMe groups as the cofactor, OLs with Ph-OH/OMe ratios between 0.44 and 0.64 showed more favorable UV-blocking performance both in the initial state and after UV irradiation. Moreover, lignin-based sunscreens exhibited increasing SPF value even after 8 h of UV exposure, confirming lignin's long-lasting UV-blocking property.

Transformation of persistent organic micropollutants by UV and UV/H2O2 in wastewater treatment plant effluent

ABSTRACT Photochemical and advanced oxidation processes (AOPs) are promising options to simultaneously disinfect wastewater treatment plant (WWTP) effluent and degrade organic micropollutants (OMPs). In the present study, kinetic experiments with UV alone and the combination of UV and hydrogen peroxide (H2O2) as an AOP were conducted in WWTP effluent (with and without ultrafiltration) to assess the degradation of 24 OMP, 13 of which were examined for the first time, in a flow-through batch reactor setup. Four parameters were systematically varied to quantify their impacts on OMP degradation: H2O2 concentrations, UV source, water matrix, and flow rate. Most of the studied OMPs (e.g., trimethylammonium, 1,3-di-o-tolylguanidine, carbamazepine) were only significantly degraded in the presence of UV radiation and H2O2. The highest pseudo-first-order rate constants were found for diclofenac, acesulfame, diatrizoate, and sulfamethoxazole. The experiment with the highest degradation also showed the strongest abatement of UV absorbance at 254 nm. Only three of the 24 substances (cyanoguanidine, melamine, and oxipurinol) were not degraded; UV alone even increased their concentrations. Overall, upgrading a UV disinfection to an AOP using H2O2 allows the degradation of a wide range of OMP, making it an interesting process for water reuse.

Atmospheric reaction of CH2=CHCH2OCF2CHF2 with OH radicals and Cl atoms, UV and IR absorption cross sections, and global warming potential.

In this work, the rate coefficients for OH radical, k1(T), and Cl atom, k2(T), reaction with allyl 1,1,2,2-tetrafluoroethyl ether, CH2=CHCH2OCF2CHF2, were studied as a function of temperature and pressure in a collaborative effort made between UCLM, Spain, and LAPKIN, Greece. OH rate coefficients were determined in UCLM, between 263 and 353K and 50-600Torr, using the absolute rate method of pulsed laser photolysis-laser-induced fluorescence technique, while Cl kinetics were studied in temperature (260-363K) and pressure (34-721Torr) ranges, using the relative rate method of the thermostated photochemical reactor equipped with Fourier transform infrared spectroscopy as the detection technique. In both OH and Cl reactions, a negative temperature dependence of the measured rate coefficients was observed, which is consistent with complex association reactions. The temperature dependence of OH rate coefficients was found to be well represented by the following expression: k1(T) = (2.30 ± 0.35) × 10-12 exp[(544 ± 46) K/T] cm3 molecule-1s-1. In the case of the Cl-initiated reaction, a slight curvature was observed in the Arrhenius plot for k2(T), and the kinetic data were fitted to a modified Arrhenius expression: k2(T) = (4.42 ± 0.32) × 10-16 T2 exp[(610 ± 22) K/T] cm3 molecule-1s-1. No pressure dependence was observed in either case. These results are consistent with a complex reaction mechanism that is not uncommon in radical association reactions to the unsaturated bond. As part of this work, UV (200-400nm) and infrared absorption spectra (500-3200cm-1) were also measured to further evaluate CH2=CHCH2OCF2CHF2 atmospheric impact. Atmospheric lifetimes with respect to OH radical and Cl atom reactions were estimated to be 19.8h and 38days, respectively, showing that OH radicals dominate atmospheric oxidation. CH2=CHCH2OCF2CHF2 is a very weak absorber in the solar actinic region, while its relatively low radiative efficiency in the atmospheric IR window, 0.0034 W m-2 ppbv-1, and the short lifetime led to a very low GWP value relative to CO2, 1.2 × 10-2 and 3.3 × 10-3, at time horizons of 20 and 100years, respectively.

Chemodiversity and Molecular Mechanism Between Per-/Polyfluoroalkyl Substance Complexation Behavior of Humic Substances in Landfill Leachate

Landfill leachate contains a range of organic and inorganic pollutants, including per-/polyfluoroalkyl substances (PFASs), which can infiltrate into surrounding soil and groundwater through leaching processes, and can pose a threat to human health via food chains and drinking water processes. Thus, the transport of PFASs in landfill leachate is a research hotspot in environmental science. This study investigates the complexation and adsorption mechanisms between humic substances and PFASs in landfill leachate at the molecular level. Experimental results demonstrate that the binding constant logKsv of humic substances with PFASs correlates positively with specific ultraviolet absorbance (SUVA254), absorbance ratio (A250/A365), humification index (HIX), and fluorescence index (FI), while it exhibits a negative correlation with the biological index (BIX). These findings indicate that high aromaticity is a prerequisite for molecular interactions between humic substances and PFASs, with polar functional groups further facilitating the interaction. Molecular-level analysis revealed that humic substances undergo complexation and adsorption with PFASs through hydrophobic interactions, van der Waals forces, hydrogen bonding, ionic bonding, and covalent bonding, by functional groups such as hydroxyl, aliphatic C-H bonds, aromatic C=C double bonds, amides, quinones, and ketones. Future efforts should focus on enhanced co-regulation and mitigation strategies addressing the combined pollution of PFASs and humic substances in landfill leachate.

High-temperature measurements of acetylene VUV absorption cross sections and application to warm exoplanet atmospheres

Most observed exoplanets have high equilibrium temperatures (T$_ eq $ > 500 K). Understanding the chemistry of their atmospheres and interpreting their observations requires the use of chemical kinetic models including photochemistry. The thermal dependence of the vacuum ultraviolet (VUV) absorption cross sections of molecules used in these models is poorly known at high temperatures, leading to uncertainties in the resulting abundance profiles. The aim of our work is to study experimentally the thermal dependence of VUV absorption cross sections of molecules of interest for exoplanet atmospheres and provide accurate data for use in atmospheric models. This study focuses on acetylene (C$_ $H$_ We measured absorption cross sections of C$_ $H$_ $ at seven temperatures ranging from 296 to 773 K recorded in the 115-230 nm spectral domain using VUV spectroscopy and synchrotron radiation. These data were used in our 1D thermo-photochemical model, to assess their impact on the predicted composition of a generic hot Jupiter-like exoplanet atmosphere. The absolute absorption cross sections of C$_ $H$_ $ increase with temperature. This increase is relatively constant from 115 to 185 nm and rises sharply from 185 to 230 nm. The abundance profile of C$_ $H$_ $ calculated using the model shows a slight variation, with a maximum decrease of 40<!PCT!> near 5 times 10$^ $ bar, when using C$_ $H$_ $ absorption cross sections measured at 773 K compared to those at 296 K. This is explained by the absorption, higher in the atmosphere, of the actinic flux from 150 to 230 nm due to the increase in the C$_ $H$_ $ absorption in this spectral range. This change also impacts the abundance profiles of other by-products such as methane (CH$_ $) and ethylene (C$_ $H$_ We present the first experimental measurements of the VUV absorption cross sections of C$_ $H$_ $ at high temperatures. Similar studies of other major species are needed to improve our understanding of exoplanet atmospheres.

Simultaneous Enhancement of Cooling Performance and Durability of the Polymer Radiative Cooler by a High UV-Reflective Polymer Multilayer Film.

The development of polymer radiative coolers with easy processing, low cost, and high inherent emissivity has significantly promoted the industrialization process of passive daytime radiative cooling. For excellent outdoor durability, however, the traditional strategy of using UV absorbers inevitably weakens the cooling performance of polymer-based coolers. The introduction of a high UV-reflective layer has been proven to be the most effective strategy to eliminate the negative effects of UV absorption and improve the durability of polymer coolers. Here, a polymer multilayer film (PMF) based on an optical interference mechanism is designed, which exhibits an average reflectance of up to 92.3% in the 300-400 nm UV wavebands. Using a TiO2-doped epoxy resin (TiO2-EP) cooler as an example, the solar reflectance of TiO2-EP increases by 5.43% after introducing PMF as a UV reflective layer. Outdoor tests without shading or convection coverage demonstrate that the average cooling temperature of TiO2-EP with PMF is further elevated by approximately 1.1 °C. Additionally, its aging rate decreases significantly, and the solar reflectance is 5.08% higher than that of TiO2-EP without PMF after 120 h of UV aging experiments. Furthermore, PMF obtains a periodic multilayer structure by multilayer coextrusion, which has the advantages of low cost and the ability to be prepared over a large area. PMF is suitable for any type of polymer cooler, providing an efficient method to further promote large-scale application of polymer coolers.

Bench to Any Side—The Pharmacology and Applications of Natural and Synthetic Alkylated Hydroxy Cinnamates and Cinnamides

Natural alkylated hydroxy cinnamates (AHCs) isolated from medicinal plants and the thereby designed and synthesized cinnamides are derivatives of hydroxy cinnamic acids such as p-coumaric, sinapic, ferulic, and caffeic acids, which are naturally derived from human dietary sources. The pharmacological properties displayed by AHCs based on their inherent structure range include antioxidant, antimicrobial, antiplasmodial, anti-tyrosinase, Alzheimer’s and Parkinson’s disease therapy, anticancer therapy, metabolic disease therapy, and biopesticides, which have not been reviewed together. Based on their inherent antioxidant, antimicrobial, and UV absorption and their structure–activity relationships, these cinnamyl esters and amides can be used for food preservation in emulsions and oils, as sun-protective components of skin care formulations, and in many other multifunctional applications. In conclusion, the fine-tuning of the structural features such as the type of hydroxy cinnamic acid used, the length of alkyl chains for variable lipophilicity, conversion from cinnamic to propanoic for antioxidants, the increase in methoxy or the change to amino groups to increase the molar absorption coefficient and loss of absorption values, the substitution by halides or amino groups for potent biopesticides, and conversion from esters to amide bonds leads to different AHCs for biomedical, cosmetic, and agriculture applications as an emerging field of investigation that can overall provide natural, safe, biodegradable, and sustainable molecules.

BaPb2(CO3)2F2: Enhancing Birefringence by a Multiunit Synergy Effect.

Carbonates are ideal birefringent materials because their π-conjugated [CO3] groups are beneficial for large anisotropy. How to maximize the birefringence and maintain a wide transmittance simultaneously in carbonates is a great challenge. Adopting a multiple-functional group synergy strategy by combining alkaline-earth metal Ba2+ with large ion radius, PbO6F distorted hexagonal pyramid, and paralleled π-conjugated CO3 triangles together, we synthesized a new metal carbonate crystal, BaPb2(CO3)2F2. BaPb2(CO3)2F2 features a typical two-dimensional layered structure, which consists of a PbCO3F monolayer parallel to the ab plane and Ba2+ cations filled between the monolayers. BaPb2(CO3)2F2 exhibits a large experimental birefringence of approximately 0.245@546 nm and a short ultraviolet absorption edge down to 264 nm (Eg = 4.70 eV), indicating that it is a promising ultraviolet birefringent material. The reported highest experimental birefringence index among carbonate crystals is surpassed by BaPb2(CO3)2F2. The theoretical calculation shows that the contribution percentages for total birefringence are 57 and 43% for the CO3 group and PbO3F group, respectively. Our work offers a new route for designing new birefringent materials with excellent comprehensive performance.

Exploring the potential of Tb and Bi-doped LaF3 as a UV absorber

Lanthanide-based nanophosphors are finding significant applicability in various fields such as LED, solar spectral convertors, lasers, and biological sensors, owing to their superior stability and luminescence properties. However, their function as a UV protector has not evolved, possibly because of their limited absorption cross-section in the UV spectral region. Hence, to overcome this limitation, in this work, a strategy to utilize Bi3+ ion as a co-dopant in LaF3:Tb3+ nanophosphor has been devised. These nanophosphors with an uniform morphology and narrow particle size distribution were synthesized using the hydrothermal method. Luminescence mechanism involving energy transfer from Bi3+ to Tb3+ was investigated. The excitation spectrum of a LaF3 nanophosphor, co-doped with Bi and Tb, reveals distinct absorption bands. Absorption ascribed to Bi3+ characterizes the UV range between 220 and 275 nm, whereas Tb3+ is associated with absorption in another UV range spanning 280 to 380 nm. This shows the potential applicability of the Bi and Tb co-doped LaF3 nanophosphors as a UV absorber. The cytotoxicity of these nanophosphors was tested on HaCaT cells, indicating their potential applicability in the healthcare field.

Ozone-microbubble-enhanced oxidation of pharmaceuticals and personal care products in municipal secondary effluents

Microbubble aeration can greatly improve ozonation by enhancing ozone transfer and subsequent hydroxyl radical formation. Here, we applied microbubble ozonation to treat pharmaceuticals and personal care products (PPCPs) in several municipal secondary effluents. Compared with conventional ozonation, microbubble ozonation efficiently eliminated both ozone-reactive and ozone-resistant PPCPs and greatly reduced the ozone doses in the complex water matrixes of the secondary effluents. In addition, compared with millibubble ozonation, the removal of chemical oxygen demand (COD) increased by 32.0%–67.2% at 60mg/L ozone dose during microbubble ozonation. The carbon emission of microbubble ozonation varied in different water matrix, and was 47–76% less than that of millibubble ozonation. The oxidizing capacity ratio of microbubble to millibubble for PPCPs was between 1.26 to 3.50 times, and ozone-resistant PPCPs removal was enhanced more than ozone-reactive PPCPs by microbubble ozonation. Specifically, the oxidizing capacity ratio of microbubble to millibubble for carbamazepine (ozone-reactive) was 1.30 to 2.43 times, whereas that for N,N-diethyl-3-tolumide (ozone-resistant) was 1.88 to 3.50 times. Microbubble ozonation also greatly decreased the UV absorbance and fluorescence for all of the water samples. The UV absorbance at 254, 280, and 320nm decreased by 64.0%–83.8%, and the fluorescence peak intensity decreased by more than 94%. Surrogates for the removal of PPCPs and COD were evaluated and compared. This study provides new insights into the application of microbubble ozonation to control PPCPs in secondary effluents.

Synthesis, Characterization, Biological, and Antioxidant Activity of New Metal Ion Complexes with Schiff Base Derived from 2-Hydroxybenzohydrazide

The study involved the synthesis of new complexes with tetradentate ligand (LH). The general formula of complexes was [M(LH)(H2O)2] with M of Ni2+, Co2+, Cu2+, and Zn+. The ligand was synthesized by treating the 2-hydroxybenzohydrazide with salicylaldehyde. The structural characteristics of ligands and complexes were analyzed using various techniques, including elemental analyses, magnetic susceptibility, molar conductivity, infrared, ultraviolet absorption, mass, and NMR spectroscopy studies. The physical measurements indicated that the prepared complexes are non-electrolyte and showed that the ligand is tetradentate when coordinated with metal ions through the nitrogen of azomethine (–C=N–), two oxygen atoms of O–H phenolic, and an oxygen atom of carbonyl (C=O) for benzohydrazide. It was found that Co2+, Cu2+, and Zn2+ complexes are octahedral, while Ni2+ complexes are square planar. The biological screening of the complexes demonstrates that the Schiff base metal complexes exhibit remarkable efficacy in combating microorganisms by utilizing Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) bacteria, as well as Candida albicans fungi. Hence, their results were good in inhibition. Then, the potential of these prepared compounds as antioxidants was determined by inhibiting free radicals.

Nanoporous gold films as a perfect NIR–UV absorber

Nanoporous gold films as a perfect NIR–UV absorber

Relationships between the spectral characteristics of dissolved organic matter and river ecological health indicators: A case study in the Shichuan River basin on a typical semi-arid and semi-humid region of China

The spectral characteristics of dissolved organic matter (DOM) in rivers are considered as potential indicators of river health status. In this study, relationships between DOM spectral properties and river ecological health indicators in Shichuan River, such as total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a) content, diversity of macrobenthic invertebrates, water quality index (WQI), and trophic level index (TLI), etc., were investigated. According to the WQI values, the water quality of the Ju River and Taoqupo Reservoir was generally better than that of other river sections, while the Qinghe and the mainstream sections performed the worst. The fluorescence index (FI) and WQI reflects that the mainstream of the Shichuan River bears a significant amount of sewage input. Besides, FI showed a significant positive correlation with nitrate nitrogen (NO3−-N), TN, TP, Chl-a, and TLI, while a significant negative correlation with WQI. The specific ultraviolet absorbance of 254 nm (SUVA254) had a positive correlation with TLI. Indeed, the UVC humic-like component (C1) showed a significant positive correlation with the macroinvertebrates diversity. The humification index (HIX) was significantly negatively correlated with sediment pollution index. Our results suggested that DOM fluorescence characteristics had the potential to be developed as a convenient method for assessing aquatic ecological health.

OCS2 Isomers in the Venusian Atmospheric Chemistry: Spectroscopic Characterization and Photochemistry

The atmosphere of Venus exhibits absorption in the 300–500 nm wavelength range, which is driven by unknown chemical processes. In our study, we explore electronic transitions in molecules that may exist in the Venusian atmosphere, specifically focusing on the photoabsorption cross sections and the lowest singlet and triplet electronic states of the OCS2, SSCO, and OSCS isomers using highly accurate ab initio methods. Our analysis suggests that the SSCO isomer is a strong candidate for explaining the unknown UV absorption. Furthermore, these isomers may serve as significant astrochemical reservoirs in the atmosphere of Venus, where photodissociation could produce atomic sulfur in both its ground and excited states along with OCS and CS2, offering a plausible mechanism for the sulfur cycle dynamics and the formation of S x species. This study provides valuable insights into the complex sulfur chemistry within the atmosphere of Venus.

CLASSY. XI. Tracing Neutral Gas Properties Using UV Absorption Lines and 21 cm Observations* ∗ Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high-z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must be able to diagnose how properties of the interstellar medium (ISM; e.g., column density, covering fraction, and outflow velocity) directly relate to the absorption features produced. Using the high-signal-to-noise and high-resolution FUV spectra of 45 nearby star-forming galaxies from the Cosmic Origins Spectrograph Legacy Spectroscopic Survey, we present the largest uniform, simultaneous characterization of neutral and low-ionization state (LIS) interstellar UV absorption lines (O i, Si ii, S ii, C ii, and Al ii) across a wide range of galaxy properties. We also present 21 cm H i observations for 35 galaxies, multiple of which are gas-poor or nondetected, possibly indicating the onset of a post-starburst phase. We find that our simultaneous one-component Voigt profile fits are capable of accurately modeling the LIS absorption for ∼75% of galaxies, mitigating challenges associated with saturation, infilling, and degeneracies. While the most massive galaxies require additional components, our one-component fits return average properties of the absorbing gas and follow the scaling relations described by a single gas cloud. We explore connections between LIS absorption and direct tracers of the neutral ISM (O i, Lyα, and H i 21 cm), finding that C ii most closely traces the neutral gas trends, while other ions exhibit weaker correlations. Given the challenges with directly observing H i at higher-z, we demonstrate that LIS absorption can be a powerful means to study the neutral ISM and present empirical relationships for predicting neutral gas properties.

Interfacial structure modification and enhanced emulsification stability of microalgae protein through interaction with anionic polysaccharides

Microalgae protein (MP) have emerged as a focal point of research within food processing due to its nutritional value and foaming properties. However, its isoelectric point around pH 4 leads to it susceptible to collision, binding, and precipitation. Additionally, MP has poor emulsification properties and only shows stability under strongly alkaline conditions. This study investigated the effects of food-grade anionic polysaccharides (guar gum (GG), gum arabic (GA), low acyl gellan gum (LG), and pectin (PT)) on the molecular structure and emulsification properties of MP. Results indicated that these anionic polysaccharides enhanced the UV absorption of MP near 620 nm, especially at 14 % content, while fluorescence intensity decreased due to amino acid residues masking without structural changes. The addition of polysaccharides resulted in bimodal or multimodal particle size distributions, with LG and PT showing larger particle sizes. At pH 4, negatively charged polysaccharides formed stable complexes with near-neutral MP, improving solution stability via electrostatic repulsion and diminishing turbidity. The droplet distribution analysis indicated that higher anionic polysaccharide ratios (1:4, 1:2, and 1:1) correlated with smaller droplet sizes and increased emulsion stability. Zeta-potential measurements revealed negative charges for emulsions, with LG-MP and PT-MP complexes displaying higher absolute values (15.0 to 20.7 mV) compared to GG-MP and GA-MP complexes, indicating superior stability. Storage stability analysis showed that LG-MP and PT-MP complexes stabilized emulsions had minimal delamination over two weeks. Rheological assessments showed that increasing GG and GA contents from 14 % to 50 % had negligible effects on apparent viscosity, while LG-MP (1:1) complexes stabilized emulsion displayed higher viscosity compared to PT-MP emulsions. Frequency sweep results showed that GG-MP, GA-MP, and LG-MP emulsions had greater elastic moduli (G') than viscous moduli (G"), indicating elastic behavior, whereas PT-MP emulsions transitioned from liquid-like to solid-like behavior as frequency increased. This study illustrates the advantages of high LG and PT content in preventing particle aggregation and enhancing emulsion stability, providing a theoretical and practical foundation for MP applications in food processing.

Whittling the photodegradation of organic photovoltaics via rational design of a UV absorption interlayer

Whittling the photodegradation of organic photovoltaics via rational design of a UV absorption interlayer

Synthetic lignin derived from ferulic acid for UV-blocking sunscreen.

Conventional lignin, a dehydrogenated polymer derived primarily from hydroxycinnamic alcohol monomers, exhibits relatively low antioxidant and ultraviolet (UV)-blocking activities due to its structural imperfection. Herein, we demonstrated that the dehydrogenated polymer of ferulic acid (an unconventional lignin precursor) (FAL) had excellent antioxidant and UV-blocking properties. Structural characterization showed that FAL contains abundant dihydrobenzofuran and butyrolactone structures, free phenolic hydroxyl groups, and cinnamic acid end groups. Such structural characteristics endow FAL with much higher antioxidant activity and broader and stronger UV absorptivity (especially UVA) than conventional lignins. Our investigation showed that FAL could significantly improve the UV-blocking property of commercial SPF30 and SPF50 and render a relatively light color. These versatile properties make the FAL a potential ingredient for application in sunscreen products. This work is enlightening not only for exploring better antioxidant and UV-blocking polymers from the dehydrogenated polymers of phenolic compounds but also for biosynthesizing more advantageous lignin in plants.