Sulfate Content Research Articles

Characterization of ‘novel fucoidan’ extracted from brown seaweed (Sargassum echinocarpum J. Ag.) using Ultrasound-Assisted Extraction (UAE) and its potential antioxidant activity

Fucoidan of Sargassum echinocarpum was extracted using the UAE method. This method produced a fucoidan extract with a yield of 2.82-3.93% and antioxidant activity of 44.57-98.77 ppm at different temperatures and extraction times. The total sulphate, fucose, phenolic, protein, and uronic acid contents were 5.50-6.24%, 17.22-63.22%, 14.66-78.20 mgGAE/g, 0-14.42 mg/g, and 191.43-353.76 mg/g, respectively. Furthermore, extraction treatment with UAE also affected the topology and morphology of the fucoidan extract. The analysis results showed the presence of monosaccharides such as galactose 1.37%, mannose 0.642%, and xylose 2.86%, while glucose and rhamnose were not detected. The extract also had the same absorption band as the fucose and fucoidan standard (F. vesiculosus) as well as a similar basic skeletal structure. Based on the experimental results, the fucoidan extract had excellent antioxidant properties.

Progressive microstructural evolution characteristics and weakening mechanism of coal exposed to acid mine drainage (AMD)

This study aims to analyze the extent of softening structural deterioration of coal pillars over time when exposed to acid mine drainage (AMD) from abandoned pits. The research involves using microscopic recognition techniques on coal samples and hydrochemistry tests in solution to identify changes in mineral compositions and microstructure parameters quantitatively. The study examines the micro-scale changes in microstructural hydro-chemical damage processes in coal samples. Based on the findings, the decrease in pH of the acidic pit effluent leads to degradation in the physical microstructural characteristics of the coal. Specifically, there is a 6.90% increase in the fractal dimension and a 23.33% rise in the area porosity. Similarly, the chemical parameters of the coal also undergo significant changes. The thickness of the aromatic layer in the coal decreases significantly, while the average diameter of the aromatic layer increases by 16.9%. The aromaticity of the coal increases, indicating noticeable deterioration of the matrix layer, particularly fragmentation. Moreover, the solution characteristics reflect the progressive coal deterioration, including increased metal ions in the soaking solution, the transformation of divalent iron to trivalent iron, and a continuous rise in sulfate content. These results have implications for assessing and maintaining load-bearing structures in underground abandoned pits subjected to long-term immersion.

Aerosol high water contents favor sulfate and secondary organic aerosol formation from fossil fuel combustion emissions

Fine-particle pollution associated with high sulfate and secondary organic aerosol (SOA) contents still occurs in winter, despite considerable reductions in precursor emissions in China. The chemical mechanisms involved are consistently acknowledged to be linked with aerosol water but remain poorly understood. Here, we present findings demonstrating that the synergistic effect of elevated aerosol water content and particles originating from fossil fuel combustion significantly enhanced the rapid formation of sulfate and SOAs under high humidity conditions during winter in northern China. The presence of high aerosol water content promoted the aging process of particles containing elemental carbon (EC) and facilitated the formation of SOAs. Evidence from single particles reveals an increased potential for SOA formation from primary organic aerosols (POAs) originating from fossil fuel combustion, in the presence of increasing aerosol water. Under conditions of relative humidity exceeding 85%, the multiphase oxidation of SO2 by in-particle nitrite/nitrous acid, generated through reactions involving aged EC-containing and iron-rich particles, as well as aqueous-phase formation of hydroxymethanesulfonate (HMS), led to a substantial increase in sulfate production. This study emphasizes the critical role of aerosol water in the aerosol chemistry concerning sulfate and SOAs, highlighting the urgent necessity to mitigate primary emissions from fossil fuel combustion.

In Vitro Anti-Inflammatory Activity and Structural Characteristics of Polysaccharides Extracted from Lobonema smithii Jellyfish.

Crude polysaccharides were extracted from the white jellyfish (Lobonema smithii) using water extraction and fractionated using ion-exchange chromatography to obtain three different fractions (JF1, JF2, and JF3). The chemical characteristics of four polysaccharides were investigated, along with their anti-inflammatory effect in LPS-stimulated RAW264.7 cells. All samples mainly consisted of neutral sugars with minor contents of proteins and sulphates in various proportions. Glucose, galactose, and mannose were the main constituents of the monosaccharides. The molecular weights of the crude polysaccharides and the JF1, JF2, and JF3 fractions were 865.0, 477.6, 524.1, and 293.0 kDa, respectively. All polysaccharides were able to decrease NO production, especially JF3, which showed inhibitory activity. JF3 effectively suppressed iNOS, COX-2, IL-1β, IL-6, and TNF-α expression, while IL-10 expression was induced. JF3 could inhibit phosphorylated ERK, JNK, p38, and NF-κB p65. Furthermore, flow cytometry showed the impact of JF3 on inhibiting CD11b and CD40 expression. These results suggest that JF3 could inhibit NF-κB and MAPK-related inflammatory pathways. The structural characterisation revealed that (1→3)-linked glucopyranosyl, (1→3,6)-linked galactopyranosyl, and (1→3,6)-linked glucopyranosyl residues comprised the main backbone of JF3. Therefore, L. smithii polysaccharides exhibit good anti-inflammatory activity and could thus be applied as an alternative therapeutic agent against inflammation.

Prolonging the Durability of Maritime Constructions through a Sustainable and Salt-Resistant Cement Composite

This research investigates the long-term resilience of an environmentally friendly cement blend comprising Egyptian Ordinary Portland Cement OPC and Ground-Granulated Blast Furnace Slag GGBFS when exposed to a corrosive seawater environment. This scientific investigation explores the effects of exposure to seawater on various properties of cement pastes, encompassing parameters such as free lime content (FLC), chemically combined water content (CWC), bulk density (BD), total porosity (ϕ), total sulfate content, total chloride content, and compressive strength (CS). By contrast, Differential Thermal Analysis (DTA), FT-IR spectroscopy, and X-ray diffraction (XRD) analysis can be utilized to investigate the influence of exposure to seawater on the hydration products of GGBFS cement pastes over a period of up to one year. This analytical approach offers valuable insights into the alterations that occur in hydration products and their resilience when subjected to seawater conditions. The results obtained from this investigation reveal that all cement pastes incorporating GGBFS exhibit heightened resistance to deterioration in seawater, with slag cement containing 60 wt. % GGBFS and achieving a notable compressive strength of 85.7 Mpa after one year of immersion in seawater. These findings underscore the capacity of these cement blends to effectively withstand challenges in durability in marine environments.

Pore characteristics of sulfate-activated coal gasification slag cement paste backfill for mining.

With the mass production of coal-based solid waste, coal mine filling can effectively consume it. The coal gasification slag is modified and prepared as coal mine filling material to meet the relevant technical requirements, which can realize the recycling of coal mine → coal chemical industry → coal mine. In this paper, in order to explore the evolution law of the mechanical properties and pore structure characteristics of the modified coal gasification slag-cement cemented paste backfill (MCGS-CPB) prepared by sodium sulfate excitation coal gasification slag, a combined macro-meso-micro testing method is used. MCGS-CPB with different sodium sulfate contents (1~5%) were prepared and tested for uniaxial compressive strength (UCS), mercury intrusion (MIP) and microscopic tests. The results show that sodium sulfate has a significant effect on the UCS and pore structure characteristics of MCGS-CPB. The mechanical properties and pore structure characteristics of MCGS-CPB were best when sodium sulfate was doped at 3%; the mechanical properties and pore structure characteristics of MCGS-CPB were deteriorated when the addition of sodium sulfate is higher than 3%. On the meso-scale, when sodium sulfate was doped with 3%, the more harmful pores of MCGS-CPB gradually changed into harmless, less harmful, and harmful pores, and the macroscopic mechanical properties were gradually improved; when the addition of sodium sulfate is higher than 3%, the harmless, less harmful, and harmful pores of MCGS-CPB gradually changed into more harmful pores, and the macroscopic mechanical properties were deteriorated. On a microscopic scale, sodium sulfate can cause MCGS-CPB to form hydration products with expansion properties. The presence of a reasonable amount of sodium sulfate in the pores of MCGS-CPB is beneficial to the development of mechanical properties. However, excessive presence will lead to the formation of expansion stress, gradual formation of micro-expansion cracks, and deteriorate the macroscopic mechanical properties. Hence, the volcanic ash activity of coal gasification slag excited by external addition of sodium sulfate should not exceed 3%. This study provides a reference value for application ratio of sodium sulfate-stimulated MCGS-CPB used in coal mine filling design.

Structural Characterization and Cytotoxic Activity Evaluation of Ulvan Polysaccharides Extracted from the Green Algae Ulva papenfussii.

Ulvan, a sulfated heteropolysaccharide with structural and functional properties of interest for various uses, was extracted from the green seaweed Ulva papenfussii. U. papenfussii is an unexplored Ulva species found in the South China Sea along the central coast of Vietnam. Based on dry weight, the ulvan yield was ~15% (w/w) and the ulvan had a sulfate content of 13.4 wt%. The compositional constitution encompassed L-Rhamnose (Rhap), D-Xylose (Xylp), D-Glucuronic acid (GlcAp), L-Iduronic acid (IdoAp), D-Galactose (Galp), and D-Glucose (Glcp) with a molar ratio of 1:0.19:0.35:0.52:0.05:0.11, respectively. The structure of ulvan was determined using High-Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Nuclear Magnetic Resonance spectroscopy (NMR) methods. The results showed that the extracted ulvan comprised a mixture of two different structural forms, namely ("A3s") with the repeating disaccharide [→4)-β-D-GlcAp-(1→4)-α-L-Rhap 3S-(1→]n, and ("B3s") with the repeating disaccharide [→4)-α-L-IdoAp-(1→4)-α-L-Rhap 3S(1→]n. The relative abundance of A3s, and B3s was 1:1.5, respectively. The potential anticarcinogenic attributes of ulvan were evaluated against a trilogy of human cancer cell lineages. Concomitantly, Quantitative Structure-Activity Relationship (QSAR) modeling was also conducted to predict potential adverse reactions stemming from pharmacological interactions. The ulvan showed significant antitumor growth activity against hepatocellular carcinoma (IC50 ≈ 90 µg/mL), human breast cancer cells (IC50 ≈ 85 µg/mL), and cervical cancer cells (IC50 ≈ 67 µg/mL). The QSAR models demonstrated acceptable predictive power, and seven toxicity indications confirmed the safety of ulvan, warranting its candidacy for further in vivo testing and applications as a biologically active pharmaceutical source for human disease treatment.

Composition and Anticoagulant Potential of Chondroitin Sulfate and Dermatan Sulfate from Inedible Parts of Garfish (Belone belone).

Glycosaminoglycans (GAGs) play a crucial role due to their significant biomedical functions. Chondroitin sulfate (CS) and dermatan sulfate (DS), the main representative family of GAGs, were extracted and purified from garfish (Belone belone) by-products, i.e., skin (GSB), bones (GCB), and heads (GHB), and their composition and anticoagulant activity were investigated. CS/DS were purified by ion-exchange chromatography with yields of 8.1% for heads, 3.7% for skin, and 1.4% for bones. Cellulose acetate electrophoresis was also explored for analyzing the extracted CS/DS. Interestingly, GHB, GSB, and GCB possessed sulfate contents of 21 ± 2%, 20 ± 1%, and 20 ± 1.5%, respectively. Physico-chemical analysis showed that there were no significant differences (p > 0.05) between the variances for sulfate, uronic acid, and total sugars in the GAGs extracted from the different parts of fish. Disaccharide analysis by SAX-HPLC showed that the GSB and GCB were predominately composed of ΔDi-4S [ΔUA-GalNAc 6S] (74.78% and 69.22%, respectively) and ΔDi-2,4S [ΔUA2S-GalNAc 4S] (10.92% and 6.55%, respectively). However, the GHB consisted of 25.55% ΔDi-6S [ΔUA-GalNAc 6S] and 6.28% ΔDi-2,6S [ΔUA2S-GalNAc 4S]. Moreover, classical anticoagulation tests were also used to measure their anticoagulant properties in vitro, which included the activated partial thromboplastin time, prothrombin time, and thrombin time. The CS/DS isolated from garfish by-products exhibited potent anticoagulant effects. The purified CS/DS showed exceptional anticoagulant properties according to this research and can be considered as a new agent with anticoagulant properties.

Assessment of heavy metals bioaccumulation in Silver Birch (Betula pendula Roth) from an AMD active, abandoned gold mine waste.

Acid mine drainage (AMD) is generally outlined as one of the largest environmental concerns, characterized by very low pH value of mine waste, heavy metals and high sulphate content. This extremely hostile environment reduces plant ability to develop and grow. Present study focuses on a silver birch (Betula pendula Roth), a pioneer species that grows on an extremely hostile gold mine waste, to investigate the bioaccumulation of rare metals (thallium (Tl) and indium (In)), as well as nine other more common heavy metals (bismuth (Bi), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), silver (Ag) and zinc (Zn)), and to asses phytoextraction and phytostabilization potential of silver birch. Additionally, parameters determining AMD process and overall contamination (pH, electrical conductivity (EC), sulphates (SO42-), arsenic (As), iron (Fe), oxidation-reduction potential (ORP), turbidity, dissolved oxygen (DO), total dissolved solids (TDS), acidity, hardness, X-ray diffraction (XRD) and radioactivity) were determined in mine waste and drainage water samples. To assess the heavy metals bioaccumulation and mine waste status, statistical geochemical indices were determined: bioaccumulation factor (BCF), pollution load index (PLI), geochemical abundance index (GAI) and exposure index (EI). The results show that silver birch bioaccumulates the essential elements Cu, Ni, Mn and Zn, and the nonessential elements Tl (average BCF = 24.99), In (average BC = 23.01) and Pb (average BCF = 0.84). Investigated mine waste was enriched by Bi, Ag and Cd according to positive values of GAI index. Present research provides a novel insight into bioaccumulation of nonessential heavy metals in silver birches who grow on the extremely hostile mine waste, and they exhibit significant phytoremediation potential.

Physicochemical Properties and Bacterial Diversity of Sediment in Sea Cucumber Culture Ponds under High Summer Temperatures

This study examined the effect of aquaculture management parameters on sea cucumbers in culture ponds during high summer temperatures. The physicochemical properties of 18 sediment samples from six sea cucumber culture ponds were assessed at a high temperature (HT) and the end of the high temperature (EHT) stages of summer. High-throughput sequencing was used to analyze the bacterial community composition and diversity of the sediment in the culture pond. The results showed that total nitrogen (TN), total carbon (TC), total organic carbon (TOC), ammonia nitrogen (NH4+), total sulfur (TS), sulfate (SO42−), and sulfide (S2−) contents were the lowest in the Geziling sediments at both stages, indicating a favorable sediment environment. The TN, TC, TOC, and NH4+ contents decreased significantly in the Wulei Island sediments during the EHT stage, indicating strong self-purification capacity. The TN, TC, TOC, NH4+, TS, SO42−, and S2− were higher in the Rushankou and Xiaohongcun sediments during both stages, indicating a worse sediment environment. Alpha diversity analysis revealed increased bacterial diversity in the sediments during the HT stage when compared to that during the EHT stage. Correlation analysis between bacterial diversity and the physicochemical properties of the TN sediments had the greatest impact on bacterial diversity, followed by TOC, TC, NH4+, TS, S2−, SO42−, and NO2− (in order). Our results suggest that the physicochemical properties (TC, TOC, TN, and NH4+) of the culture pond sediment can significantly influence bacterial community composition and diversity. Management measures for aquaculture, including desilting and monthly water change, could positively affect these physicochemical properties and the bacterial community structure of the sediment. These findings will provide a reference for healthier aquaculture practices of Apostichopus japonicus under high summer temperatures.

Chemical Composition, Antioxidant, and Antitumor Activity of Fucoidan from the Brown Alga Dictyota dichotoma.

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05-1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity.

A Review of Chondroitin Sulfate's Preparation, Properties, Functions, and Applications.

Chondroitin sulfate (CS) is a natural macromolecule polysaccharide that is extensively distributed in a wide variety of organisms. CS is of great interest to researchers due to its many in vitro and in vivo functions. CS production derives from a diverse number of sources, including but not limited to extraction from various animals or fish, bio-synthesis, and fermentation, and its purity and homogeneity can vary greatly. The structural diversity of CS with respect to sulfation and saccharide content endows this molecule with distinct complexity, allowing for functional modification. These multiple functions contribute to the application of CS in medicines, biomaterials, and functional foods. In this article, we discuss the preparation of CS from different sources, the structure of various forms of CS, and its binding to other relevant molecules. Moreover, for the creation of this article, the functions and applications of CS were reviewed, with an emphasis on drug discovery, hydrogel formation, delivery systems, and food supplements. We conclude that analyzing some perspectives on structural modifications and preparation methods could potentially influence future applications of CS in medical and biomaterial research.

Investigation on the sulfate attack of metakaolin blended recycled concrete based on percolation theory

Recycled aggregate concrete (RAC) is one of the most important ways to achieve sustainable development for concrete industry. However, the research on durability, especially on sulfate transport and erosion mechanism, of RAC needs deep investigation. Pore structure evolution is a vital parameter for sulfate transport, which is difficult to be traced. To investigate the dynamic changes of pore structure in metakaolin blended RAC under sulfate erosion, percolation theory is addressed in this study. Firstly, dry and wet cycle was applied to accelerate the sulfate transport in metakaolin (MK) blended RAC systems. Then the compressive strength of the samples after sulfate attack was measured to evaluate the sulfate erosion degree. Furthermore, backscattered electron imaging (BSE) was used to acquire the percolation parameters, such as wet site ratio, percolation probability and so forth. Finally, sulfate content and compressive strength of the sample were related to the percolation probability. Results present that MK exhibits excellent resistance to sulfate erosion and can be used to enhance the performance of RAC. There is a certain correlation between the degree of sulfate erosion, compressive strength, and percolation parameters. The influence of the number of dry–wet cycles and MK content on sulfate ion transport can be demonstrated using percolation theory, which can be employed for predicting sulfate transport and revealing erosion mechanisms. This enables a clear understanding of the ion transport mechanisms within concrete and holds significant importance on the investigation of durability issues of RAC.

Substrate and fertigation management modulate microgreens production, quality and resource efficiency

Long-term space missions will require a self-sustaining food production system to meet the crew’s nutritional and health needs. For this purpose, plant-based food production systems with elevated resource efficiency are required, based on advanced agricultural technologies that produce phytonutrient-rich crops. In addition to the resource requirements for crop production on Earth, volume and time efficiency become essential factors to consider for food production in space. Microgreens represent a promising candidate for space farming as they have a high harvest index, short cultivation cycle, and high nutritional potential. However, the development of specific technical protocols for growing microgreens in space is essential since different agronomic inputs, such as substrates and fertigation, can modulate productivity, quality and resource efficiency of microgreens cultivation. The current work examines the effects of different substrates (coconut fiber and cellulose sponge) and nutrient solution (NS) management strategies (quarter strength Hoagland and half strength Hoagland/osmotic water) on the production of two species of microgreens [Raphanus sativus cv. Saxa 2 (Radish); Brassica oleracea var. capitata f. sabauda cv. Vertus (Savoy cabbage)]. The appraisal focused on (i) biomass production and quality, and (ii) sizing of space facilities devoted to the production of phytonutrients required for the astronauts’ wellbeing. In our study, the interaction among species, substrate and NS significantly affected the accumulation of fructose, sucrose, total soluble non-structural carbohydrates and nitrate as well as the daily production of total ascorbic acid and, in turn, the required microgreens serving to supply its adequate daily intake. Species-substrate interaction effects on fresh yield, dry yield, dry matter, anthocyanins, TPC, β-carotene and sulfate content as well as the cultivation surface required to produce the adequate daily intake of ascorbic acid (AscA) were assessed. Substrate-NS interaction modulated the anthocyanins, violaxanthin and sulfate contents independently of species. On the other hand, single factor effects were identified with respect to the accumulation of lutein, chlorophylls, glucose, and starch. Therefore, the management of microgreens cultivation in terms of NS and substrate is an effective tool to meet the phytochemical requirements of the crew.

Effect of different enzymes on thermal and structural properties of gluten, gliadin, and glutenin in triticale whole-wheat dough

Three enzymes promoted the development of the gluten network in triticale whole-wheat noodles (TWWN). To further understand the mechanism of gluten enhancement, the effects of three enzymes on the structure of gluten and its fractions (gliadin and glutenin) were evaluated. The results showed that glucose oxidase (GOD), xylanase (XYL), and laccase (LAC) decreased the content of sodium dodecyl sulfate (SDS) extractable proteins. The content of glutenin subunits was reduced by 17.25 %, 30.60 %, and 20.09 % with the addition of GOD, XYL, and LAC, respectively. Furthermore, GOD and LAC increased the content of glutenin macropolymer (GMP) by 2.64 % and 7.71 %, respectively, suggesting the promotion of glutenin aggregation. The addition of three enzymes decreased the weight loss and increased the degradation temperature of the gluten and its fractions. GOD and XYL decreased the fluorescence intensity of gluten and its fractions, except for XYL which increased the fluorescence intensity of glutenin by 10.50 %. Intermolecular interactions and surface hydrophobicity were enhanced by XYL in gluten and its fractions. GOD and LAC decreased the free sulfhydryl content and increased the β-sheet content, suggesting that the covalent interaction between gluten fractions was enhanced. Therefore, this research can enrich the theoretical study of enzymatic cross-linking.

Physicochemical Quality Assessment of Drinking Water Sources in Wukari Town, Nigeria

In this study, an assessment of drinking water sources in Wukari town, Nigeria was carried out using standard methods. Thirty (30) water samples collected from three sources (Borehole, hand dug wells and town supply) were evaluated for physicochemical properties. Among the parameters investigated, pH was found to range from 6.41 – 8.41, conductivity was in the range 80 – 600 µS/cm, turbidity ranged between 0.15 – 7 NTU, total dissolved solids (TDS) ranged from 7.54 – 154.6 mg/L and total hardness was in the range of 21 – 112 mg/L. Chemical oxygen demand (COD) and dissolved oxygen (DO) ranged between 50 – 110 mg/L and 3.12 – 14.47 mg/L. Chloride and sulphate contents ranged between 28 – 128 mg/L and 1.65 – 19.34 mg/L respectively. The levels obtained in this study were mostly within the WHO recommended limits with few exceptions which are; turbidity, dissolved oxygen and nitrates in some samples. Water quality Index (WQI) which was evaluated by means of the weighted arithmetic method revealed a score of 39.40 for borehole samples, 61.60 for town water supply samples and 88.04 for well water samples. These values indicate good water quality for the borehole source, poor water quality for town supply and very poor water quality for well water.

Progressive damage process and destabilization precursor recognition of sulfate tailing-cemented paste backfill based on acoustic emission

Sulfate-rich tailings are commonly used as aggregate materials for mine filling, and the sulfate retained within them significantly affects the structural characteristics of cemented paste backfill (CPB). A series of microstructure tests, uniaxial compressive strength (UCS) tests, and acoustic emission (AE) monitoring were carried out on CPB and sulfate tailing-cemented paste backfill (ST-CPB) to investigate the progressive damage pattern and identify the destabilization precursor information of the backfill. The results showed that the UCS of the backfill increased and then decreased with the increase in sulfate content, and 1.5% was the optimal content. The AE counts, energy, amplitude, and peak frequency time series corresponded to each other, exhibited the stage characteristics of a stress curve and were significantly affected by sulfate content. CPB and 0.5% ST-CPB displayed more active AE counts and energy during the initial loading stage, with high amplitude and low-frequency signals. However, the 1.5% ST-CPB exhibited active AE events and medium-high amplitude and medium-low frequency signals only during the plastic yielding and damage stages. 2.5% ST-CPB exhibited more active AE signals during the entire loading process. RA-AF values indicate that CPB and 2.5% ST-CPB reached 93.12 and 96.62% of tensile cracks at final failure, respectively. Meanwhile, the percentages of tensile cracks at the final failure of 0.5 and 1.5% ST-CPB were 76.65 and 76.86%, respectively. The sudden increase in the variance curve and the rapid decrease in the b value of AE in the critical slowdown theory were identified as the precursor characteristics of the backfill instability. This investigation can provide technical and theoretical support for the progressive damage characteristic and stability assessment of ST-CPB.

Media-milled agar particles as a novel emulsifier for food Pickering emulsion

Pickering emulsions was successfully fabricated using ball-milled agar particles with sizes and sulfate content around 7 μm and 0.62 %, respectively. These particles were obtained through a simple media-milling process using agar powders initially sized at 120 μm. The lamellated agar is aggregated into a mass after the milling process. The surface charge and hydrophobicity of the ball-milled agar particles were characterized through zeta potential and contact angle measurements, respectively. The droplet size of Pickering emulsions was related to oil fraction and particle concentration, ranging from approximately 45 μm to 80 μm. Ball-milled agar stabilized emulsions were sensitive to pH and salt conditions. The results of confocal laser scanning microscopy and cryo-SEM showed that at low particle concentrations and oil fractions, ball-milled agar stabilized the emulsions by dispersing particles on the surface of the oil droplets through electrostatic repulsion. Conversely, ball-milled agar stabilized the emulsions under high particle concentrations and oil fractions by forming a gel network structure to bind the oil droplets. In this research, this developed method provides the basis for the high-value application of agar and a new idea for preparing stable food-grade Pickering emulsion-based functional foods using raw-food material without surface wettability.

Polysaccharides from red seaweeds: Effect of extraction methods on physicochemical characteristics and antioxidant activities

Seaweed polysaccharides are reported to possess biological and medicinal properties. Specifically, the antioxidant activity of seaweed extracts is the subject of intensive research due to ever-increasing demands from the food and pharmaceutical industries. The structure and composition of polysaccharides (carrageenan, xylan) extracted from four red seaweed species: Chondrus crispus (CC), Ahnfeltiopsis devoniensis (AD), Sarcodiotheca gaudichaudii (SG) and Palmaria palmata (PP) were compared and correlated with their antioxidant activity. Crude polysaccharide extracts were characterized by NMR (1H and 13C), HPLC-SEC, and FTIR spectroscopy. Total phenolic content (TPC), total sugars, sulfate and protein content were determined using spectrophotometric methods. The antioxidant capacity of each fractionated polysaccharide sample was evaluated by the following methods: DPPH (2,2-diphenyl-1-picrylhydrazyl radical), ABTS (2,2-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]), superoxide dismutase (SOD), ferric-reducing power in FRAP (Ferric-reducing Antioxidant Power) assays, and the hydroxyl radical (OH) scavenging capacity assay. The highest antioxidant activity was found in extracts from A. devoniensis (ι/κ hybrid carrageenan), while the lowest was in P. palmata (xylans). Moreover, Chondrus crispus extracts did not possess SOD inhibition activity. Polysaccharides evaluated in this study offer high potential for applications in the food, pharmaceutical and biotechnology industries.

Оцінка сучасного гідрохімічного стану деяких рибогосподарських ставів Київщини

Purpose. To assess the quality of the hydrochemical regime of fishponds, the territory of which suffered massive missile strikes or was directly a combat zone or close to the front line. Methodology. Chemical parameters of water including the content of ammonium nitrogen, nitrites, nitrates, phosphates and total iron were measured by the photometric method, while chloride concentration of chlorides by the argentometric titration method. The hydrogen indicator (pH) was determined electrometrically, and sulfate content and mineralization by the gravimetric method. All the above-mentioned methods are generally accepted in the comprehensive assessment of the ecological state of fishponds. Findings. The total amount of mineral salts dissolved in water was studied and analyzed in laboratory conditions, namely: the concentrations of calcium, magnesium, chlorine, bicarbonate ions and sulfate ions. The determined permanganate oxidizability in the investigated ponds exceeded the normative values by 72, 49, 31, and 42%, respectively. The concentration of nitrates ranged from 19.96 to 6.34 mg N/dm3, nitrites from 0.33 to 0.11 mgN/dm3, which indicates the intensity of decomposition of organic substances and indicates a certain degree of contamination of ponds. The amount of total iron in the studied ponds ranged from 1.98 to 1.17 mgFe/dm3, respectively. A slight increase in mineral phosphorus in ponds No. 1 and No. 2 was established by 31 and 26%, respectively, which can probably be related to both the decomposition of zooplankton and the input of pollutants from the outside from the surrounding areas. The obtained results of the laboratory analysis of the chemical composition of water samples as well as their comparison with the normative values for water bodies used for aquaculture provide a basis for assessing the current hydrochemical state of the investigated ponds of Kyiv region Originality. For the first time, a hydrochemical analysis of fishponds in Kyiv Region was conducted, the territory of which suffered massive missile strikes or was directly a combat zone or close to the front line. Practical value. The obtained results will contribute to a better understanding of the current ecological state of fishponds in Kyiv region. Keywords: water body, chemical analysis of water, toxic substances, ecological condition.