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Compared Ions and Organics by AMS, IC and Carbon Analyzer in Okinawa Aerosols
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Purification of Two Taxanes from Taxus cuspidata by Preparative High-Performance Liquid Chromatography
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Testing Thymol-Based DES for the Elimination of 11 Textile Dyes from Water
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Simple and Sensitive Analysis of Clenbuterol in Urine Matrices by UHPLC-MS/MS Method with Online-SPE Sample Preparation
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Capsule Phase Microextraction Combined with Chemometrics for the HPLC Determination of Amphotericin B in Human Serum
Journal Description
Separations
Separations
- formerly Chromatography - is an international, scientific, peer-reviewed, open access journal on separation and purification science and technology in all areas of chemical, biological, physical science, and separation performance published monthly online by MDPI. The Central European Group of Separation Sciences (CEGSS) is affiliated with Separations and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Chemistry, Analytical)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 11.6 days after submission; acceptance to publication is undertaken in 3.8 days (median values for papers published in this journal in the second half of 2022).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
3.344 (2021);
5-Year Impact Factor:
2.943 (2021)
Latest Articles
Synthesis and Characterization of Electrospun Sorbent for the Solid-Phase Extraction of Fluoroquinolones in Human Plasma and Their UHPLC-PDA Determination
Separations 2023, 10(2), 104; https://doi.org/10.3390/separations10020104 - 02 Feb 2023
Abstract
In this work we investigated the synthesis and the characterization of electrospun polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) stabilized in air, made in a 5:1 ratio, used as sorbent for the solid-phase extraction of fluoroquinolones in plasma samples and the following quantification in
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In this work we investigated the synthesis and the characterization of electrospun polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) stabilized in air, made in a 5:1 ratio, used as sorbent for the solid-phase extraction of fluoroquinolones in plasma samples and the following quantification in UHPLC-PDA. Preliminary analyses of viscosity were carried out on the polymer solution to be sure about the electrospinability. Characterizations were performed on the electrospun membrane to evaluate the morphology (SEM scanning electron microscopy and AFM atomic force microscopy), the thermal degradation behavior (TGA thermogravimetric analysis), the porosity and the surface area (BET, Brunauer Emmett Teller), and the quantitative and qualitative distribution of atomic structures (FTIR infrared analysis in Fourier transform and EDX Energy Dispersive X-ray analysis). A solid-phase extraction method was developed by studying parameters such as the amount of sorbent and the pH of the sample. Finally, a UHPLC-PDA method for the analysis of fluoroquinolones was developed and validated in accordance with the guidelines and successfully applied. The use of the prepared sorbent combined with UHPLC-PDA has allowed the development of a method whose strengths are its speed, accuracy, sensitivity, and high recoveries.
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(This article belongs to the Special Issue Recent Advances in Microextraction Technology for Analytical Sample Preparation)
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Extraction, Characterization, and Antioxidant Activity of Polysaccharides from Ajwa Seed and Flesh
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, , , , , , and
Separations 2023, 10(2), 103; https://doi.org/10.3390/separations10020103 - 02 Feb 2023
Abstract
The date palm has been cultivated in dry and hot areas of the planet for much of human history. In the Kingdom of Saudi Arabia, dates are the main crop used as a source of food. Among several species of date fruits, the
[...] Read more.
The date palm has been cultivated in dry and hot areas of the planet for much of human history. In the Kingdom of Saudi Arabia, dates are the main crop used as a source of food. Among several species of date fruits, the Ajwa AL-Madinah date is unique, growing only in Al-Madinah geographical region. The Ajwa date is used in traditional medicine due to its abundant active components and therapeutic properties. This study investigates the structural properties and the antioxidant effects of water-soluble polysaccharides extracted from Ajwa flesh and seed. The polysaccharides were isolated by two techniques including hot water and ultrasonic extraction. After isolation and partial purification, the physicochemical properties of four samples of polysaccharides extracted from flesh and seed were studied by several techniques including FTIR, solid-state NMR, elemental analysis, and mass spectrometry. Several radical scavenging experiments were combined to study the antioxidant activity of the polysaccharide compounds. FTIR and NMR results showed a structure typical of heterogeneous polysaccharides. Mass spectrometry revealed that the polysaccharide samples were composed mainly of mannose, glucose, galactose, xylose, arabinose, galacturonic acid, and fucose. In addition, the physicochemical properties and composition of polysaccharides extracted from flesh and seed were compared. The extracted polysaccharides showed antioxidant activity, with 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, Fe chelating ability, hydroxyl free radical scavenging ability, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. These results highlight their potential to be a useful nutritional element or supplemental medication.
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(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)
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Pattern Recognition of Phytoconstituents and Bioactivities of Date Pit Extracts from Different Cultivars Grown in the Qassim Area
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, , , , , , , , and
Separations 2023, 10(2), 102; https://doi.org/10.3390/separations10020102 - 02 Feb 2023
Abstract
A huge number of date varieties grow annually throughout the world. The genetic variation between different date varieties is reflected in their variable sensory characters and phytochemical contents. Date pits are considered a waste product of the date industry, despite their rich metabolic
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A huge number of date varieties grow annually throughout the world. The genetic variation between different date varieties is reflected in their variable sensory characters and phytochemical contents. Date pits are considered a waste product of the date industry, despite their rich metabolic content. The present study attempts to generate visual clustering to clarify the diversity among fourteen date cultivars growing in the Qassim region, according to the phytochemical contents and biological potentials of their pits. The results indicated a wide variation in the total phenolic content (11.4–29.7 mg GAE/g), flavonoids content (21.9–37.1 mg RE/g), proanthocyanidine content (12.0–207.0 mg CE/g), and antioxidant potential (10.3–25.5 mg AEAC/g) among the tested cultivars. Screening the antimicrobial activity of extracts from the 14 tested cultivars indicated different activities against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Candida albicans. Multivariate analysis of phytochemical content and biological activity, using different analytical models, allowed the classification of the 14 cultivars into four classes, Class-1: Barhi, Safawi, and Sukkari; Class-2: Khodry and Nabtat Ali; Class-3: Ruthana, Segae, Shaqra, and Sheishee; and Class-4: Hulwa Aljouf, Mabroom, Meneifi, Rushodia, and Wannana. These findings provide a scientific basis for the classification of date pits which facilitates the future selection of promising candidates for more phytochemical and biological exploration.
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(This article belongs to the Special Issue Chemical Analysis and Biological Activity of Compounds in Plants)
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Spectroscopic Tracking of the Characteristics of Microplastic-Derived Dissolved Organic Matter
Separations 2023, 10(2), 101; https://doi.org/10.3390/separations10020101 - 01 Feb 2023
Abstract
Microplastic-derived dissolved organic matter (MP-DOM) has received increasing attention in recent years. In this study, the fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was used to track the leaching behavior of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate
[...] Read more.
Microplastic-derived dissolved organic matter (MP-DOM) has received increasing attention in recent years. In this study, the fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was used to track the leaching behavior of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) MP-DOM. After seven days of leaching, PVC reached a leaching concentration of 7.59 mg/L, and the other four microplastics reached approximately 4.5~4.7 mg/L. The leaching activity of PVC was considerably more active in an alkaline environment and under UV irradiation. All the fluorescence signals of MP-DOM components were located in the protein/phenol-like fluorescence region. The fact that C1 and C2 were found in every microplastic revealed that these substances took up quite a large proportion of MP-DOM. Protein/phenolic substances in MP-DOM showed different binding ability with different heavy metals, which can be realized from the log K values calculated for Cr3+ (3.99–5.51), Cu2+ (3.06–4.83), Cd2+ (3.76–4.41), and Fe3+ (3.11–5.03). This work introduced more MP-DOM samples, and offered spectroscopic insight into the characteristics and environmental fate of MP-DOM at a molecular level. Furthermore, this study displayed the potential applicability of using the integrated methods to track the MP-DOM formation process and environmental behavior in natural aquatic systems.
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(This article belongs to the Special Issue Advanced Analytical Methods for Environmental Pollutants Detection)
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Cytotoxic, Scolicidal, and Insecticidal Activities of Lavandula stoechas Essential Oil
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, , , , , and
Separations 2023, 10(2), 100; https://doi.org/10.3390/separations10020100 - 01 Feb 2023
Abstract
Essential oils (EOs) have recently attracted more interest due to their insecticidal activities, low harmfulness, and rapid degradation in the environment. Therefore, Lavandula steochas (L. steochas) essential oil was assessed for its chemical constituents, in vitro cytotoxicity, and scolicidal, acaricidal, and insecticidal
[...] Read more.
Essential oils (EOs) have recently attracted more interest due to their insecticidal activities, low harmfulness, and rapid degradation in the environment. Therefore, Lavandula steochas (L. steochas) essential oil was assessed for its chemical constituents, in vitro cytotoxicity, and scolicidal, acaricidal, and insecticidal activities. Using spectrometry and gas chromatography, the components of L. steochas EOs were detected. Additionally, different oil concentrations were tested for their anticancer activities when applied to human embryonic kidney cells (HEK-293 cells) and the human breast cancer cell line MCF-7. The oil’s scolicidal activity against protoscolices of hydatid cysts was evaluated at various concentrations and exposure times. The oil’s adulticidal, larvicidal, and repelling effects on R. annulatus ticks were also investigated at various concentrations, ranging from 0.625 to 10%. Likewise, the larvicidal and pupicidal activities of L. steochas against Musca domestica were estimated at different concentrations. The analyses of L. steochas oil identified camphor as the predominant compound (58.38%). L. steochas oil showed significant cytotoxicity against cancer cells. All of the tested oil concentrations demonstrated significant scolicidal activities against the protoscoleces of hydatid cysts. L. steochas EO (essential oil) showed 100% adulticidal activity against R. annulatus at a 10% concentration with an LC50 of 2.34%, whereas the larvicidal activity was 86.67% and the LC50 was 9.11%. On the other hand, the oil showed no repellent activity against this tick’s larva. Furthermore, L. steochas EO achieved 100% larvicidal and pupicidal effects against M. domestica at a 10% concentration with LC50 values of 1.79% and 1.51%, respectively. In conclusion, the current work suggests that L. steochas EO could serve as a potential source of scolicidal, acaricidal, insecticidal, and anticancer agents.
Full article
(This article belongs to the Special Issue Analysis of Natural Bioactive Compounds in Plant, Food, and Pharmaceutical Products Using Chromatographic Techniques)
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Determination of Sodium, Potassium, and Magnesium as Sulfate Salts in Oral Preparations Using Ion Chromatography and Conductivity Detection
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, , , and
Separations 2023, 10(2), 99; https://doi.org/10.3390/separations10020099 - 01 Feb 2023
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An ion chromatography technique with conductivity detection was selected as an analytical tool for the simultaneous indirect determination of sodium sulfate, potassium sulfate, and magnesium sulfate via their respective cations. The method was developed and validated for the quantitative assay of the inorganic
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An ion chromatography technique with conductivity detection was selected as an analytical tool for the simultaneous indirect determination of sodium sulfate, potassium sulfate, and magnesium sulfate via their respective cations. The method was developed and validated for the quantitative assay of the inorganic salts under study in oral pharmaceutical dosage forms. Chromatographic separation was achieved on a Dionex®IonPac® CS16 column (250 × 5 mm) column using the gradient elution method. A mobile phase-A consisting of methane sulfonic acid (6.7%, v/v) in Milli-Q water, which is used together with Milli-Q water, was used as a mobile Phase-B. The flow rate was 1.2 mL/min. The retention times of sodium, potassium, and magnesium as sulfates were 7.8, 12.8, and 16.2 min, respectively. The method was validated according to ICH guidelines and showed good linearity and accuracy results within concentration ranges of 80.0–240.0, 20.0–60.0, and 4.5–13.5 ppm for sodium, potassium, and magnesium as sulfates, respectively. The relative standard deviation results for intra- and inter-day precision were less than 1.0%. The method was applied successfully for determination of the analytes under study in their mixed pharmaceutical oral solution and found suitable for their routine and stability analysis.
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Greener Stability-Indicating HPLC Approach for the Determination of Curcumin in In-House Developed Nanoemulsion and Curcuma longa L. Extract
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, , , , , and
Separations 2023, 10(2), 98; https://doi.org/10.3390/separations10020098 - 01 Feb 2023
Abstract
Despite the fact that several analytical methodologies have been reported for the determination of curcumin (CCM) in a wide range of sample matrices, the greener liquid chromatographic approaches to determine CCM are scarce in the literature. Therefore, this research is designed to develop
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Despite the fact that several analytical methodologies have been reported for the determination of curcumin (CCM) in a wide range of sample matrices, the greener liquid chromatographic approaches to determine CCM are scarce in the literature. Therefore, this research is designed to develop and validate a greener stability-indicating “high-performance liquid chromatography (HPLC)” methodology to determine CCM in an in-house developed nanoemulsion, Curcuma longa L. extract, and commercial tablets. CCM was measured on a Nucleodur (150 mm × 4.6 mm) RP C18 column with 5 µm-sized particles. Ethanol and ethyl acetate (83:17 v/v) made up the greener eluent system, which was pumped at a flow speed of 1.0 mL/min. At a wavelength of 425 nm, CCM was detected. The greener HPLC methodology was linear in the 1–100 µg/mL range, with a determination coefficient of 0.9983. The greener HPLC methodology for CCM estimation was also rapid (Rt = 3.57 min), accurate (%recoveries = 98.90–101.85), precise (%CV = 0.90–1.11), and sensitive (LOD = 0.39 µg/mL and LOQ = 1.17 µg/mL). The AGREE approach predicted the AGREE score of 0.81 for the established HPLC technique, indicating an outstanding greenness profile. The utility of the greener HPLC methodology was demonstrated by determining CCM in the in-house developed nanoemulsion, Curcuma longa extract, and commercial tablets. The % amount of CCM in the in-house developed nanoemulsion, Curcuma longa extract, and commercial tablets was found to be 101.24%, 81.15%, and 78.41%, respectively. The greener HPLC methodology was able to detect its degradation product under various stress conditions, suggesting its stability-indication characteristics. These results suggested that CCM in developed nanoemulsion, plant extract samples, and commercial tablets may be routinely determined using the greener HPLC methodology.
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(This article belongs to the Special Issue Analysis of Natural Bioactive Compounds in Plant, Food, and Pharmaceutical Products Using Chromatographic Techniques)
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Synthesis, Characterization and Application of Novel Cationic Surfactants as Antibacterial Agents
Separations 2023, 10(2), 97; https://doi.org/10.3390/separations10020097 - 01 Feb 2023
Abstract
It is of great necessity to develop new antimicrobial agents to overcome the accelerated increment in drug-resistant bacteria. The main aim of this work is to manufacture two cationic surfactants, QHETA-9 and QHETA-14, based on quaternary hexamethylenetetramine with long alkyl chains (C-9 and
[...] Read more.
It is of great necessity to develop new antimicrobial agents to overcome the accelerated increment in drug-resistant bacteria. The main aim of this work is to manufacture two cationic surfactants, QHETA-9 and QHETA-14, based on quaternary hexamethylenetetramine with long alkyl chains (C-9 and C-14) by simple one-step alkylation reaction. These surfactants were characterized by analytical and statistical data, including FTIR, 1H NMR, 13C NMR and DLS. The antibacterial activities of QHETA-9 and QHETA-14 against some pathogenic bacterial strains were tested using agar disk diffusion method. The results exhibited that QHETA-14 has higher antibacterial activity than that of QHETA-9. It displayed inhibitory zone values for Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis, as Gram-positive bacteria, of 22.7, 21.5 and 25.9 mm, respectively, at 200 μg/disk. Meanwhile, it recorded inhibition zone values of 17.5, 25.2 and 23.8 mm for Escherichia coli, Agrobacterium tumefaciens and Erwinia carotovora, respectively, at 200 μg/disk. As a result, the current investigation verified that the antibacterial properties of QHETA-14 were greater than those of QHETA-9 due to the increase in the length of the alkyl chain. It is clear that QHETA-14 has the potential to be used as an antibacterial agent against bacteria that cause nosocomial infections and food poisoning diseases.
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(This article belongs to the Special Issue Isolation and Structure Elucidation of Antibacterial Compound)
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Durian Waste Husks as an Adsorbent in Improving Soaking Water during the Retting Process of Piper nigrum L. (Pepper Berries)
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, , , , , and
Separations 2023, 10(2), 96; https://doi.org/10.3390/separations10020096 - 01 Feb 2023
Abstract
The potential of raw durian husk and NaOH-modified durian husk as an adsorbent, using different doses, 0.5 g, 1.0 g, 1.5 g, and 2.0 g, is investigated to improve soaking water of pepper berries during the retting process. The surface area and the
[...] Read more.
The potential of raw durian husk and NaOH-modified durian husk as an adsorbent, using different doses, 0.5 g, 1.0 g, 1.5 g, and 2.0 g, is investigated to improve soaking water of pepper berries during the retting process. The surface area and the pore size of the durian husk were examined using Brunner Emmett and Teller analysis. The surface area of NaOH-modified durian husk is higher (2.33 m2/g) compared to the raw durian husk (1.51 m2/g). NaOH-modified durian husk has a higher porous structure than the raw durian husk, but both pore diameters are more than 50 nm, which is considered micropore raw material. The effect of the raw durian husk on pH, chemical oxygen demand (COD), dissolved oxygen (DO), and turbidity were compared to the NaOH-modified durian husk with different doses. The 2.0 g of NaOH-modified durian husk enhanced changes in the four parameters. The highest pH value using NaOH-modified durian husk was 6.10 ± 0.02, while turbidity and COD increased to 971.33 ± 1.15 NTU and 1984.67 ± 3.21 mg/L, respectively. The DO of NaOH-modified durian husk shows the lowest reduction to 1.49 mg/L with 2.0 g of NaOH-modified durian husk. The experimental data was best fitted with a first-order kinetic model. Durian husk treated with NaOH could be used as a potential adsorbent to enhance the soaking water for pepper berries.
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(This article belongs to the Special Issue Advanced Techniques in the Separation Processes and Development of Novel Adsorbents)
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Separation of Ilmenite from Vanadium Titanomagnetite by Combining Magnetic Separation and Flotation Processes
Separations 2023, 10(2), 95; https://doi.org/10.3390/separations10020095 - 31 Jan 2023
Abstract
Vanadium titanomagnetite (VTM) is an important mineral for developing titanium resources, but the comprehensive recovery of ilmenite separation is extremely poor, resulting in the low-efficiency utilization of titanium resources. Here, the separation of ilmenite from VTM ore is studied by combining magnetic separation
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Vanadium titanomagnetite (VTM) is an important mineral for developing titanium resources, but the comprehensive recovery of ilmenite separation is extremely poor, resulting in the low-efficiency utilization of titanium resources. Here, the separation of ilmenite from VTM ore is studied by combining magnetic separation and flotation technologies. In particular, the floatability of mixed MOH/PG-1 collectors is thoroughly investigated. The results show that a concentrate with a TiO2 grade of 9.90% can be separated via weak magnetic separation and coarse particle tailing dumping. The concentrate grade is then increased to 14.32% via strong magnetic separation and floating separation of sulfur minerals. Finally, a TiO2 grade of 46.34% is obtained through closed-circuit flotation using mixed MOH/PG-1 collectors. The mixed collectors are very efficient and can enhance the chemical adsorption of the Ti4+, Fe3+, and Fe2+ ions in the ilmenite concentrate compared with the MOH collector, thereby increasing the TiO2 grade and recovery by 3.31% and 1.20%, respectively. This is beneficial for improving the comprehensive utilization of titanium resources in VTM ores.
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(This article belongs to the Special Issue Mineral Flotation)
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Calluna vulgaris Crude Extract Reverses Liver Steatosis and Insulin Resistance-Associated-Brain Lesion Induced by CCl4 Administration
Separations 2023, 10(2), 94; https://doi.org/10.3390/separations10020094 - 31 Jan 2023
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Fatty liver (FL) is one of the most prevalent diseases in the world, characterized by insulin resistance and hyperlipidemia, which consequently lead to neurodegenerative disorders through the induction of oxidative stress-inflammatory axis, which alters the neurotransmitters’ levels. Calluna vulgaris (CV), also known
[...] Read more.
Fatty liver (FL) is one of the most prevalent diseases in the world, characterized by insulin resistance and hyperlipidemia, which consequently lead to neurodegenerative disorders through the induction of oxidative stress-inflammatory axis, which alters the neurotransmitters’ levels. Calluna vulgaris (CV), also known as heather, has anti-inflammatory and antidepressant properties, making it a promising candidate for treating steatosis and brain lesions. This study aimed to assess the prophylactic and therapeutic effect of CV extract on brain dysfunction associated with steatosis. FL was induced in rats by CCl4 oral administration (50 µL/Kg in olive oil three times/week) for six weeks. The protection group received 200 mg/kg CV extract orally for two weeks before and two weeks during FL induction, while the treatment group was orally administered CV extract after FL induction for one month. The biochemical parameters revealed that CCl4 administration induced hepatotoxicity as blood-liver function parameters (AST, ALT, ALP, protein, and LDH) were increased by 1.8, 1.4, 2, 2.4, and 1.2-fold, respectively. Moreover, insulin resistance was characterized by a two-fold increase in the glucose, insulin, and lipid profile when compared to control one, at p < 0.05. Steatosis liver demonstrated a two-fold increase in all following parameters— acetaldehyde (AC), prooxidant (TBARS), acetylcholine esterase (AChE), monoamine oxidase (MAO), hyaluronidase, and ATPase—when compared to control one, at p < 0.05. CCl4 administration led to brain lesions where the brain level of TBARS, insulin, cholesterol, AChE, and MAO was progressively increased by 2, 1.6, 2.2, 4, and 1.6-fold, respectively, that was associated with reduced glucose (8-fold) and GSH (2-fold) than that of control level, at p < 0.05. CV extract as a prophylactic and therapeutic agent increased GSH and decreased TBARS of both the liver and brain than that of induced group, at p < 0.05, normalized the activities of AChE and MAO, and increased insulin sensitivity where they successfully decreased the HOMA-IR, glucose, TG, and cholesterol compared to than that of induced group, at p < 0.05. This positive effect of CV extract contributed to the presence of polyphenolic compounds such as catechins (5.501 ± 0.056 µg/g extract), gallic (3.525 ± 0.143 µg/g) extract, and protocatechuic acid (2.719 ± 0.132 µg/g extract). Therefore, we concluded that FL induced brain dysfunction through the formation of ROS and elevation of insulin and lipid inside the brain tissue, which alter the amount of neurotransmitter and cellular energy production. Rich in polyphenolic compounds, CV extract functions as an antioxidant, antidiabetic, hepatoprotective, inhibitor of neurotransmitter catabolizing enzymes, and a regulator for energy production. Therefore, it can be used as a preventative or treatment for NAFLD and brain damage.
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Determination of Ultra-Trace Amounts of Copper in Environmental Water Samples by Dispersive Liquid-Liquid Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry
Separations 2023, 10(2), 93; https://doi.org/10.3390/separations10020093 - 30 Jan 2023
Abstract
A new method of dispersive liquid-liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination of ultra-trace copper. It was based on the reaction of Cu(II) with the laboratory-prepared chelating agent 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in a HAc-NaAc buffer
[...] Read more.
A new method of dispersive liquid-liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination of ultra-trace copper. It was based on the reaction of Cu(II) with the laboratory-prepared chelating agent 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in a HAc-NaAc buffer solution at pH 5.0 to form stable hydrophobic chelates, which were separated and enriched by DLLME with chlorobenzene (C6H5Cl) and acetonitrile (CH3CN) as extraction and disperser solvents, respectively. The sedimented phase containing the chelates was then determined with GFAAS. Various operating variables that may be affected by the extraction process such as the pH of the solution, the concentration of the chelating agent 5-Br-PADMA, the types and volumes of extraction and disperser solvents, the extraction time, and the centrifugation time were investigated. Under optimum conditions, the calibration curve was linear in the range from 0.02 ng/mL to 0.16 ng/mL of copper with a correlation coefficient of r = 0.9961, and the detection limit was 0.01 ng/mL based on 3Sb. The relative standard deviation for six replicate measurements of 0.05 ng /mL of copper was 3.9%. An enrichment factor (EF) of 110 was obtained. The method has the advantages of low detection limit, high sensitivity, simple operation, less consumption of organic solvents, higher enrichment factor, and environmental friendliness and was applied to the determination of trace copper in environmental water samples with satisfactory results.
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(This article belongs to the Special Issue Analytical Separation Techniques for Environmental Analysis)
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Trend of Antioxidant Activity and Total Phenolic Content in Wild Edible Plants as Part of the Environmental Quality Assessment of Some Areas in the Central Italy
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, , , , , , and
Separations 2023, 10(2), 92; https://doi.org/10.3390/separations10020092 - 30 Jan 2023
Abstract
Polyphenols are secondary metabolites of interest due to their potential application in various fields. This study is supposed to analyse the content of total polyphenols, total tannins, condensed tannins and antioxidant activity of ten wild plant species of nutritive interest to better understand
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Polyphenols are secondary metabolites of interest due to their potential application in various fields. This study is supposed to analyse the content of total polyphenols, total tannins, condensed tannins and antioxidant activity of ten wild plant species of nutritive interest to better understand their potential applications. Furthermore, the effect of heavy metals on the production of the investigated secondary metabolites was analysed. The different phenolic compounds were determined in methanol extracts obtained from edible plants collected during three sampling periods (June, September and November–December) in four areas of the Central Italy. Analyses were carried out by applying standard methodologies. In particular, total polyphenols were determined by the Folin–Ciocalteu method, total tannins by the polyvinylpolypyrrolidone (PVPP) reagent and condensed tannins by the 4-(dimethylamino)cinnamaldehyde (DMCA). Antioxidant activity was determined by assessing the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results showed a satisfactory content of phenolic compounds and antioxidant activity for all species analysed. Furthermore, the existence of a negative correlation between the presence of heavy metals and phenolic compounds was found. Results proved the potential use of these plants for balanced feeding of ruminants.
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(This article belongs to the Special Issue Chemical Analysis and Biological Activity of Compounds in Plants)
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Volatile and Non-Volatile Content Determination and Biological Activity Evaluation of Fresh Humulus lupulus L. (cv. Chinook) Leaves and Inflorescences
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, , , , , , and
Separations 2023, 10(2), 91; https://doi.org/10.3390/separations10020091 - 29 Jan 2023
Abstract
In this work, the fresh leaves and inflorescences of Humulus lupulus L. cv. Chinook hops were investigated in order to describe their chemical composition and evaluate their biological activities. The analyses were carried out first on fresh untreated samples and then on pulverized
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In this work, the fresh leaves and inflorescences of Humulus lupulus L. cv. Chinook hops were investigated in order to describe their chemical composition and evaluate their biological activities. The analyses were carried out first on fresh untreated samples and then on pulverized ones using the SPME-GC-MS technique. In total, forty-two molecules belonging to different chemical classes were identified, and among these, twenty-three were terpene compounds. In order to carry out the activity assays, the powders were subjected to extraction with two different solvents (methanol and distilled water) by stirring and subsequent sonication at room temperature. To chemically characterize the extracts, the methanolic ones were analyzed by direct injection into the GC-MS apparatus, while the aqueous ones were analyzed by DI-SPME-GC-MS. In addition, with the aim to obtain information on the non-volatile content of the methanolic extracts, they were also subjected to derivatization, and the silylated derivatives were analyzed by GC-MS. The antioxidant activity was then evaluated by means of DPPH and ABTS assays after the determination of the total content of polyphenols and flavonoids. The greatest effects were observed on the methanolic extracts rather than on the aqueous ones. Furthermore, a preliminary study on the cytotoxic power of the methanolic extracts was also conducted on three different human cancer cell lines, such as non-small cell lung cancer (H1299), melanoma (A375) and breast cancer (MCF7). The obtained results showed that the two extracts induced a marginal effect on reducing breast tumor, melanoma and non-small cell lung cancer cell proliferation.
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(This article belongs to the Special Issue Extraction and Characterization of Bioactive Based on Chromatography/Mass Spectrometry)
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A Comparative Study on Extraction and Physicochemical Properties of Soluble Dietary Fiber from Glutinous Rice Bran Using Different Methods
by
, , , , , , , , and
Separations 2023, 10(2), 90; https://doi.org/10.3390/separations10020090 - 29 Jan 2023
Abstract
The methods of hot water extraction and ultrasound-assisted enzymatic treatment were applied for extracting the soluble dietary fiber from the glutinous rice bran in the study. Based on the single factor experiment for the hot water method, the optimum parameters of the extraction
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The methods of hot water extraction and ultrasound-assisted enzymatic treatment were applied for extracting the soluble dietary fiber from the glutinous rice bran in the study. Based on the single factor experiment for the hot water method, the optimum parameters of the extraction time of 120 min, solid-liquid ratio 1:20 (w/v), and pH 8.0, as well as the extraction temperature 80 °C, were obtained, while the yield and purity of SDF reached 31.83 ± 0.06% and 93.28 ± 0.27%, respectively. Furthermore, the SDF yield was improved to 34.87 ± 0.55% by using the ultrasound-assisted enzymatic treatment under the optimum conditions of cellulase dosage 9 × 103 U/g and ultrasonic temperature of 50 °C. Similar polysaccharide compositions were detected based on the infrared spectroscopic analysis. Compared with the SDF obtained from hot water extraction, the whiteness, solubility, water holding capacity, and swelling properties of SDF extracted by ultrasound-assisted enzymatic method improved significantly. These results demonstrated that both two strategies could be applied to SDF extraction in practical production, and the ultrasound-assisted enzymatic method might be an effective tool to improve the functional properties of SDF.
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(This article belongs to the Special Issue Extraction and Analysis of Active Ingredients from Natural Products)
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Open AccessArticle
Pharmacognostical and Phytochemical Evaluation of a Unani Polyherbal Formulation: Dawa ul Kurkum by HPTLC
by
, , , , , , and
Separations 2023, 10(2), 89; https://doi.org/10.3390/separations10020089 - 28 Jan 2023
Abstract
Background: Dawa ul Kurkum (Duk) is a widely used Unani formulation. It consists of seven plant herbs, including stigmas of Crocus sativus L., rhizomes of Nardostachys jatamansi (D.Don) DC., the bark of Cinnamomum cassia (L.) J. Presl., shoot of Cymbopogon jwarancusa (Jones ex
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Background: Dawa ul Kurkum (Duk) is a widely used Unani formulation. It consists of seven plant herbs, including stigmas of Crocus sativus L., rhizomes of Nardostachys jatamansi (D.Don) DC., the bark of Cinnamomum cassia (L.) J. Presl., shoot of Cymbopogon jwarancusa (Jones ex Roxb.) Schult., the resin of Commiphora wightii (Arn.) Bhandari, roots of Saussurea lappa (Decne.) Sch.Bip., and bark of Cinnamomum zeylanicum Blume. However, no study has been previously conducted to characterize this formulation. Thus, the present study was designed to carry out the pharmacognostic and phytochemical characterization of Duk. Methods: Duk was prepared following the protocols in Bayaz e Kabeer and The National Formulary of Unani Medicine Part-I. The characterization included organoleptic properties, fluorescence analysis, preliminary phytochemical screening, antioxidant activity, and active constituent profiling using HPTLC. Results: Evaluation of Duk showed the presence of carbohydrates, flavonoids, quinones, glycosides, cardiac glycosides, terpenoids, phenols, coumarin, steroids, and phytosterols. The total phenolic and flavonoid content was 5.75 ± 0.23 mg GAE/g and 10 ± 0.18 mg QUE/g, respectively. HPTLC of Duk showed the presence of p-coumaric acid, cinnamaldehyde, citral, crocin, isovaleric acid, guggulsterone, and dehydrocostus lactone. Conclusions: Our findings supported the use of Duk as a conventional medicine, and these results could be used as a reference for the standardization of Duk.
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(This article belongs to the Special Issue Application of Chromatography in Pharmaceutical and Biomedical Analysis)
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Open AccessArticle
Functionalization of Sodium Magnesium Silicate Hydroxide/Sodium Magnesium Silicate Hydrate Nanostructures Using 2,3-Dihydroxybenzaldehyde as a Novel Nanocomposite for the Efficient Removal of Cd(II) and Cu(II) Ions from Aqueous Media
Separations 2023, 10(2), 88; https://doi.org/10.3390/separations10020088 - 28 Jan 2023
Abstract
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Cd(II) and Cu(II) ions cause many diseases in humans. Therefore, they should be removed from water sources using simple and cost-effective adsorbents. Consequently, sodium magnesium silicate hydroxide/sodium magnesium silicate hydrate nanostructures were synthesized and functionalized using 2,3-dihydroxybenzaldehyde as a novel nanocomposite. Several instruments
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Cd(II) and Cu(II) ions cause many diseases in humans. Therefore, they should be removed from water sources using simple and cost-effective adsorbents. Consequently, sodium magnesium silicate hydroxide/sodium magnesium silicate hydrate nanostructures were synthesized and functionalized using 2,3-dihydroxybenzaldehyde as a novel nanocomposite. Several instruments were used to characterize the synthetic products, such as an X-ray diffractometer (XRD), a Fourier-transform infrared spectrophotometer (FT-IR), an N2 adsorption/desorption analyzer, a CHN elemental analyzer, an energy-dispersive X-ray spectrophotometer (EDS), and a field emission scanning electron microscope (FE-SEM). The functionalization of the nanostructures with 2,3-dihydroxybenzaldehyde led to the disappearance of the XRD peaks of the nanostructures and the presence of a broad XRD peak at 2θ = 32°. In addition, the FE-SEM images revealed that the nanostructures consisted of spheres, cubes, and irregular shapes with an average grain size of 115 nm, and the nanocomposite consisted of spherical conglomerates consisting of needle-like shapes. The anticipated morphology following the functionalization of the nanostructures with 2,3-dihydroxybenzaldehyde resulted from the presence of 2,3-dihydroxybenzaldehyde on the backbones of the nanostructures. The EDS results showed that the nanostructures were composed of O, Na, Mg, and Si with weight percentages equal to 38.59%, 5.95%, 16.60%, and 38.86%, respectively. Additionally, the nanocomposite was composed of C, N, O, Na, Mg, and Si with weight percentages equal to 55.31%, 2.23%, 30.09%, 6.56%, 2.98%, and 12.83%, respectively. The synthesized nanostructures and nanocomposite samples were utilized for the efficient removal of cadmium and copper ions from aqueous media using the ion exchange and chelation adsorption procedures, respectively. Optimum conditions for removing the cadmium and copper ions were achieved at a pH, time, and temperature equal to 7.5, 80 min, and 298 K, respectively. The maximum uptake capacities of the synthesized nanostructures and nanocomposite samples toward cadmium ions were 89.44 mg/g and 155.04 mg/g, respectively, and the maximum uptake capacities of the synthesized nanostructures and nanocomposite samples toward copper ions were 103.73 mg/g and 177.94 mg/g, respectively. Moreover, the adsorption processes were exothermic, chemical, and followed the pseudo-second-order model and Langmuir equilibrium isotherm model.
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Open AccessArticle
Development and Validation of a Bioanalytical Method for the Quantification of Nitrated Fatty Acids in Plasma Using LC-MS/MS: Application to Cardiovascular Patients
Separations 2023, 10(2), 87; https://doi.org/10.3390/separations10020087 - 27 Jan 2023
Abstract
Nitrated fatty acids (NO2-FAs) are a newly discovered class of biologically active compounds with distinct biochemical features that induce physiologically beneficial alterations in transcriptional regulatory protein function, leading to a variety of modulatory and protective actions. The most common NO2
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Nitrated fatty acids (NO2-FAs) are a newly discovered class of biologically active compounds with distinct biochemical features that induce physiologically beneficial alterations in transcriptional regulatory protein function, leading to a variety of modulatory and protective actions. The most common NO2-FAs identified in vivo so far are nitro oleic acid (NO2-OA), nitro linoleic acid (NO2-LA) and its structural isomer nitro-conjugated linoleic acid (NO2-cLA). Analytical limitations that compromise accurate quantitation of these endogenous compounds are their low concentrations, compromised stability and different distribution profiles in tissues and biofluids. As a result, reliable analytical methods for the quantitative determination of their endogenous levels are rare. Only NO2-OA was quantified by GC-MS while LC-MS methods are still scarce. In this work, an LC-MS/MS bioanalytical method was developed and validated for the quantification of NO2-OA and NO2-LA in human plasma via a standard addition protocol after protein precipitation, liquid extraction and LC-MS/MS analysis in the negative ion mode. Quantification was performed via multiple reaction monitoring of the transitions m/z 326 > 46 and m/z 324 > 46 for NO2-OA and NO2-LA, respectively, and m/z 269 > 250 for the internal standard heptadecanoic acid. Linear responses were observed for both analytes over the studied range (R2 = 0.9805 and 0.9644 for NO2-OA and NO2-LA, respectively). Sufficient accuracy and precision were also achieved at low, medium and high levels within the linearity range. The limits of quantification of our method (2 nM for both NO2-FAs) were below basal endogenous levels, thereby providing a good tool to accurately measure these NO2-FAs in plasma. We applied the validated method to compare NO2-OA and NO2-LA levels in the plasma of 28 ischemic heart disease (IHD) patients and 18 healthy controls. The levels of NO2-OA were found to be significantly higher in the plasma of patients (21.7 ± 9.8 nM) versus healthy controls (12.6 ± 6 nM) (p-value < 0.01). Whereas the levels of NO2-LA were comparable in both groups (3 ± 1 nM in patients, 3.2 ± 1.7 nM in controls, p-value = 0.87288). The early elevation of NO2-OA in plasma samples, which were collected 2–3 h post myocardial injury, implies the potential use of NO2-OA levels as a biomarker for IHD after further investigation with a larger number of IHD patients. To our knowledge, this is the first comparative study on the levels of NO2-FAs in humans with and without IHD.
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(This article belongs to the Special Issue Application of Hyphenated Techniques in Bioanalysis and Metabolite Identification)
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Simultaneous Quantification of Avermectins in Six Aquatic Foods by UHPLC/FLD with Precolumn Derivatization
Separations 2023, 10(2), 86; https://doi.org/10.3390/separations10020086 - 27 Jan 2023
Abstract
In this study, a fast, concise and reliable ultra-high performance liquid chromatography-fluorescence (UHPLC/FLD) detection method for simultaneous quantification of avermectins (AVMs), including avermectin (AVM), ivermectin (IVM), emamectin (EMM), moxidectin (MOX) and doramectin (DOR) in six aquatic foods was established. Based on the QuEChERS
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In this study, a fast, concise and reliable ultra-high performance liquid chromatography-fluorescence (UHPLC/FLD) detection method for simultaneous quantification of avermectins (AVMs), including avermectin (AVM), ivermectin (IVM), emamectin (EMM), moxidectin (MOX) and doramectin (DOR) in six aquatic foods was established. Based on the QuEChERS pretreatment method, the samples were extracted with 0.2% (v/v) ammonia acetonitrile. N-methyl imidazole mixed with acetonitrile (1:1, v/v) and trifluoroacetic anhydride with acetonitrile (1:2, v/v) were used as derivatization reagents. The mobile phase consists of acetonitrile and water with a flow rate of 1.0 mL/min. An Infinity Lab Poroshell 120 EC-C18 column was used for optimum chromatographic separation of target analytes at 40 °C; the excitation and emission wavelengths were set at 365 nm and 465 nm, respectively. In six kinds of aquatic foods, the limits of detection (LODs) of AVM, IVM, EMM, MOX, and DOR were 2.7 μg/kg, 1.8 μg/kg, 2.1 μg/kg, 1.2 μg/kg, and 2.7 μg/kg, respectively, and the limits of quantification (LOQs) of AVM, IVM, EMM, MOX, and DOR were 5 μg/kg, 4.5 μg/kg, 4.5 μg/kg, 3.5 μg/kg and 5.0 μg/kg, respectively. The recoveries were all above 85.38% when the samples were spiked with the target compounds at the concentration level of 5, 10, 50, and 100 μg/kg. The intra-day and inter-day relative standard deviations (RSDs) were all less than 15%. This method considers the requirements of sensitivity, accuracy, and economics of the instrument.
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Open AccessArticle
Archaeological Evidence for the Dietary Practices and Lifestyle of 18th Century Lisbon, Portugal—Combined Steroidal Biomarker and Microparticle Analysis of the Carbonized Faecal Remains
by
, , , , , , and
Separations 2023, 10(2), 85; https://doi.org/10.3390/separations10020085 - 27 Jan 2023
Abstract
The study of the urban context in the contemporary center of Portugal’s capital city uncovered traces of daily lives that were abruptly interrupted and utterly transformed by the Great Lisbon Earthquake on the morning of 1 November 1755. Charred organic residue was recovered
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The study of the urban context in the contemporary center of Portugal’s capital city uncovered traces of daily lives that were abruptly interrupted and utterly transformed by the Great Lisbon Earthquake on the morning of 1 November 1755. Charred organic residue was recovered from a cylindrical vessel excavated from the storage area of the town house at the Rossio square. The archaeological sample was studied through a multi-analytical approach based on microstructural, elemental and biomolecular characterization by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR), variable pressure scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (VP-SEM-EDS), and gas chromatography coupled with mass spectrometry (GC-MS). The residue was identified as human faeces collected in the ceramic vessel for disposal, and further analysis provided additional information about diet and the living conditions in the 18th century.
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(This article belongs to the Special Issue Chromatography in Our Cultural Heritage)
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