Displaying publications 1 - 20 of 51 in total

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  1. Khan MN
    Adv Colloid Interface Sci, 2010 Sep 15;159(2):160-79.
    PMID: 20673861 DOI: 10.1016/j.cis.2010.06.005
    A new method, based upon semi-empirical kinetic approach, for the determination of ion exchange constant for ion exchange processes occurring between counterions at the cationic micellar surface is described in this review article. Basically, the method involves a reaction kinetic probe which gives observed pseudo-first-order rate constants (k(obs)) for a nucleophilic substitution reaction between the nonionic and anionic reactants (R and S) in the presence of a constant concentration of both reactants as well as cationic micelles and varying concentrations of an inert inorganic or organic salt (MX). The observed data (k(obs), versus [MX]) fit satisfactorily (in terms of residual errors) to an empirical equation which could be derived from an equation explaining the mechanism of the reaction of the kinetic probe in terms of pseudophase micellar (PM) model coupled with another empirical equation. This (another) empirical equation explains the effect of [MX] on cationic micellar binding constant (K(S)) of the anionic reactant (say S) and gives an empirical constant, K(X/S). The magnitude of K(X/S) is the measure of the ability of X(-) to expel S(-) from a cationic micellar pseudophase to the bulk aqueous phase through ion exchange X(-)/S(-). The values of K(X/S) and K(Y/S) (where Y(-) is another inert counterion) give the ion exchange constant, K(X)(Y) (=K(X)/K(Y) where K(X) and K(Y) represent cationic micellar binding constants of X(-) and Y(-), respectively). The suitability of this method is demonstrated by the use of three different reaction kinetic probes and various MX.
    Matched MeSH terms: Physicochemical Phenomena
  2. Mathew S, Zakaria ZA
    Appl Microbiol Biotechnol, 2015 Jan;99(2):611-22.
    PMID: 25467926 DOI: 10.1007/s00253-014-6242-1
    Pyroligneous acid (PA) is a complex highly oxygenated aqueous liquid fraction obtained by the condensation of pyrolysis vapors, which result from the thermochemical breakdown or pyrolysis of plant biomass components such as cellulose, hemicellulose, and lignin. PA produced by the slow pyrolysis of plant biomass is a yellowish brown or dark brown liquid with acidic pH and usually comprises a complex mixture of guaiacols, catechols, syringols, phenols, vanillins, furans, pyrans, carboxaldehydes, hydroxyketones, sugars, alkyl aryl ethers, nitrogenated derivatives, alcohols, acetic acid, and other carboxylic acids. The phenolic components, namely guaiacol, alkyl guaiacols, syringol, and alkyl syringols, contribute to the smoky odor of PA. PA finds application in diverse areas, as antioxidant, antimicrobial, antiinflammatory, plant growth stimulator, coagulant for natural rubber, and termiticidal and pesticidal agent; is a source for valuable chemicals; and imparts a smoky flavor for food.
    Matched MeSH terms: Physicochemical Phenomena
  3. Sheshala R, Khan N, Chitneni M, Darwis Y
    Arch Pharm Res, 2011 Nov;34(11):1945-56.
    PMID: 22139694 DOI: 10.1007/s12272-011-1115-y
    The aim of this study was to formulate cost effective taste-masked orally disintegrating tablets of ondansetron, a bitter drug using different superdisintegrants by a wet granulation technique. Microcrystalline cellulose (Avicel) as a diluent and disintegrant in addition to aspartame as a sweetener were used in all formulations. The prepared tablets were evaluated for weight variation, thickness, hardness, friability, drug content, water content, in vitro disintegration time and in vitro drug release. The tablets' hardness was maintained in the range of 2-3 kg and friability was <1% for all batches. All tablet formulations disintegrated rapidly in vitro within 5.83 to 33.0 sec. The optimized formulation containing 15% Polyplasdone XL-10 released more than 90% of drug within 5 min and the release was comparable to that of a commercial product. In human volunteers, optimized formulation was found to have a pleasant taste and mouth feel and they disintegrated in the oral cavity within 12 sec. The stability results were also satisfactory. A pharmacokinetic study with the optimized formulation was performed in comparison with a reference (Zofer MD 8®) and they were found to be bioequivalent. In conclusion, a cost effective ondansetron orally disintegrating tablet was successfully prepared with acceptable hardness, desirable taste and rapid disintegration in the oral cavity.
    Matched MeSH terms: Physicochemical Phenomena
  4. Miskandar MS, Man YC, Yusoff MS, Rahman RA
    Asia Pac J Clin Nutr, 2005;14(4):387-95.
    PMID: 16326646
    Optimum processing conditions on palm oil-based formulations are required to produce the desired quality margarine. As oils and fats contribute to the overall property of the margarine, this paper will review the importance of beta' tending oils and fats in margarine formulation, effects of the processing parameters -- emulsion temperature, flow-rate, product temperature and pin-worker speed -- on palm oil margarines produced and their subsequent behaviour in storage. Palm oil, which contributes the beta' crystal polymorph and the best alternative to hydrogenated liquid fats, and the processing conditions can affect the margarine consistency by influencing the solid fat content (SFC) and the types of crystal polymorph formed during production as well as in storage. Palm oil, or hydrogenated palm oil and olein, in mixture with oils of beta tending, can veer the product to the beta' crystal form. However, merely having beta' crystal tending oils is not sufficient as the processing conditions are also important. The emulsion temperature had no significant effect on the consistency and polymorphic changes of the product during storage, even though differences were observed during processing. The consistency of margarine during storage was high at low emulsion flow-rates and low at high flow rates. The temperature of the scraped-surface tube-cooler is the most important parameter in margarine processing. High temperature will produce a hardened product with formation of beta-crystals during storage. The speed of the pin-worker is responsible for inducing crystallization but, at the same time, destroys the crystal agglomerates, resulting in melting.
    Matched MeSH terms: Physicochemical Phenomena
  5. Idris NA, Dian NL
    Asia Pac J Clin Nutr, 2005;14(4):396-401.
    PMID: 16326647
    Inter-esterification is one of the processes used to modify the physico-chemical characteristics of oils and fats. Inter-esterification is an acyl-rearrangement reaction on the glycerol molecule. On the other hand, hydrogenation involves addition of hydrogen to the double bonds of unsaturated fatty acids. Due to health implications of trans fatty acids, which are formed during hydrogenation, the industry needs to find alternatives to hydrogenated fats. This paper discusses some applications of inter-esterified fats, with particular reference to inter-esterified palm products, as alternatives to hydrogenation. Some physico-chemical properties of inter-esterified fats used in shortenings are discussed. With inter-esterification, more palm stearin can be incorporated in vanaspati. For confectionary fats and infant formulations, enzymatic inter-esterification has been employed.
    Matched MeSH terms: Physicochemical Phenomena
  6. Lay MM, Karsani SA, Banisalam B, Mohajer S, Abd Malek SN
    Biomed Res Int, 2014;2014:410184.
    PMID: 24818141 DOI: 10.1155/2014/410184
    In recent years, the utilization of certain medicinal plants as therapeutic agents has drastically increased. Phaleria macrocarpa (Scheff.) Boerl is frequently used in traditional medicine. The present investigation was undertaken with the purpose of developing pharmacopoeial standards for this species. Nutritional values such as ash, fiber, protein, fat, and carbohydrate contents were investigated, and phytochemical screenings with different reagents showed the presence of flavonoids, glycosides, saponin glycosides, phenolic compounds, steroids, tannins, and terpenoids. Our results also revealed that the water fraction had the highest antioxidant activity compared to the methanol extract and other fractions. The methanol and the fractionated extracts (hexane, chloroform, ethyl acetate, and water) of P. macrocarpa seeds were also investigated for their cytotoxic effects on selected human cancer cells lines (MCF-7, HT-29, MDA-MB231, Ca Ski, and SKOV-3) and a normal human fibroblast lung cell line (MRC-5). Information from this study can be applied for future pharmacological and therapeutic evaluations of the species, and may assist in the standardization for quality, purity, and sample identification. To the best of our knowledge, this is the first report on the phytochemical screening and cytotoxic effect of the crude and fractionated extracts of P. macrocarpa seeds on selected cells lines.
    Matched MeSH terms: Physicochemical Phenomena/drug effects
  7. Abioye OP, Agamuthu P, Abdul Aziz AR
    Biodegradation, 2012 Apr;23(2):277-86.
    PMID: 21870160 DOI: 10.1007/s10532-011-9506-9
    Soil contamination by hydrocarbons, especially by used lubricating oil, is a growing problem in developing countries, which poses a serious threat to the environment. Phytoremediation of these contaminated soils offers environmental friendly and a cost effective method for their remediation. Hibiscus cannabinus was studied for the remediation of soil contaminated with 2.5 and 1% used lubricating oil and treated with organic wastes [banana skin (BS), brewery spent grain (BSG) and spent mushroom compost (SMC)] for a period of 90 days under natural conditions. Loss of 86.4 and 91.8% used lubricating oil was recorded in soil contaminated with 2.5 and 1% oil and treated with organic wastes respectively at the end of 90 days. However, 52.5 and 58.9% oil loss was recorded in unamended soil contaminated with 2.5 and 1% oil, respectively. The plant did not accumulate hydrocarbon from the soil but shows appreciable accumulation of Fe and Zn in the root and stem of H. cannabinus at the end of the experiment. The first order kinetic rate of uptake of Fe and Zn in H. cannabinus was higher in organic wastes amendment treatments compared to the unamended treatments, which are extremely low. The results of this study suggest that H. cannabinus has a high potential for remediation of hydrocarbon and heavy metal contaminated soil.
    Matched MeSH terms: Physicochemical Phenomena
  8. Ishak MR, Sapuan SM, Leman Z, Rahman MZ, Anwar UM, Siregar JP
    Carbohydr Polym, 2013 Jan 16;91(2):699-710.
    PMID: 23121967 DOI: 10.1016/j.carbpol.2012.07.073
    Sugar palm (Arenga pinnata) is a multipurpose palm species from which a variety of foods and beverages, timber commodities, biofibres, biopolymers and biocomposites can be produced. Recently, it is being used as a source of renewable energy in the form of bio-ethanol via fermentation process of the sugar palm sap. Although numerous products can be produced from sugar palm, three products that are most prominent are palm sugar, fruits and fibres. This paper focuses mainly on the significance of fibres as they are highly durable, resistant to sea water and because they are available naturally in the form of woven fibre they are easy to process. Besides the recent advances in the research of sugar palm fibres and their composites, this paper also addresses the development of new biodegradable polymer derived from sugar palm starch, and presents reviews on fibre surface treatment, product development, and challenges and efforts on properties enhancement of sugar palm fibre composites.
    Matched MeSH terms: Physicochemical Phenomena
  9. Vakhrusheva T, Panasenko O
    Chem Phys Lipids, 2006 Apr;140(1-2):18-27.
    PMID: 16458872
    In this work, we studied whether chondroitin sulfates and dextran sulfates (DXSs) can influence hypochlorite-induced peroxidation of phosphatidylcholine (PC) liposomes. Multilamellar liposomes (2 mg lipid/ml) were prepared in phosphate buffer, pH 7.4, with NaCl or not and exposed to reagent HOCl/ClO- (1mM) at 37 degrees C in the presence of different concentrations of chondroitin 6-sulfate (C6S), chondroitin 4-sulfate (C4S), DXS 8000, DXS 40,000, and DXS 500,000. Lipid peroxidation was assessed by thiobarbituric acid-reactive substance (TBARS) production. DXSs and C6S enhanced TBARS production in a dose-dependent manner. The decline in TBARS production at the relatively high C6S concentrations may be attributed to C4S present in C6S, since in contrast to C6S, C4S is known to react with hypochlorite. Dextrans, nonsulfated analogues of DXS, failed to modulate TBARS production. This fact indicates the important role of negatively charged sulfate groups for DXS to facilitate hypochlorite-induced peroxidation of PC liposomes. The electrostatic nature of the mechanism providing for the pro-oxidative effect of DXS was also supported by the influence of liposome surface charge and solution ionic strength on the extent of liposome peroxidation. The addition of calcium ions to the incubation mixture did not prevent the pro-oxidative action of DXS. The relevance of the results to atherogenesis is discussed.
    Matched MeSH terms: Physicochemical Phenomena
  10. Anuar MS, Briscoe BJ
    Drug Dev Ind Pharm, 2010 Aug;36(8):972-9.
    PMID: 20515396 DOI: 10.3109/03639041003610807
    It is generally accepted that the tablet elastic relaxation during compaction plays a vital role in undermining the final tablet mechanical integrity. One of the least investigated stages of the compaction process is the ejection stage.
    Matched MeSH terms: Physicochemical Phenomena
  11. Fauzi SH, Rashid NA, Omar Z
    Food Chem, 2013 Apr 15;137(1-4):8-17.
    PMID: 23199984 DOI: 10.1016/j.foodchem.2012.09.086
    Blends of palm stearin (PS), palm kernel oil (PKO) and soybean oil (SBO) at certain proportions were formulated using a mixture design based on simplex-lattice (Design Expert 8.0.4 Stat-Ease Inc., Minneapolis, 2010). All the 10 oil blends were subjected to chemical interesterification (CIE) using sodium methoxide as the catalyst. The solid fat content (SFC), triacylglycerol (TAG) composition, thermal properties (DSC), polymorphism and microstructural properties were studied. Palm-based trans-free table margarine containing ternary mixture of PS/PKO/SBO [49/20/31 (w/w)], was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SMP and SFC profile as compared to the commercial table margarine. This study has shown chemical interesterification are effective in modifying the physicochemical properties of palm stearin, palm kernel oil, soybean oil and their mixtures.
    Matched MeSH terms: Physicochemical Phenomena
  12. Choo SY, Leong SK, Henna Lu FS
    Food Sci Technol Int, 2010 Dec;16(6):531-41.
    PMID: 21339169 DOI: 10.1177/1082013210367546
    The substitution of milk fat with virgin coconut oil (VCO) was used to produce nutritious ice cream with pleasant coconut flavor and aroma. Three formulations were developed whereby formulation VCO4, VCO8 and VCO12 was substituted with 4%, 8% and 12% of VCO, respectively. The physicochemical properties of ice creams analyzed include overrun, meltdown, pH, titratable acidity, total solid, protein and fat content. The fatty acids profile of VCO formulated ice creams and their stabilities over 3 and 6 weeks storage were studied respectively using gas chromatography (GC). Qualitative descriptive analysis (QDA) and consumer affective test were performed among the trained and untrained panelists. Significant differences (p < 0.05) of overrun, pH, total solid, protein and fat content between ice cream formulations were observed except titratable acidity. Increased VCO content in ice cream formulations lowered the melting resistance of ice cream. For GC analysis, the major fatty acid identified was lauric acid. Upon storage time, the concentration of unsaturated fatty acid decreased but the concentration of saturated fatty acid increased. The result of QDA showed that formulation VCO4, VCO8 and VCO12 were significantly (p < 0.05) different in attributes of color, firmness and smoothness as compared to the control ice cream. Formulation VCO12 was highly accepted by panelists in terms of the acceptance level of appearance, aroma, texture, flavor and overall acceptability. Hence, it has a potential marketable value.
    Matched MeSH terms: Physicochemical Phenomena
  13. Bhat R, Karim AA
    Int J Food Sci Nutr, 2009;60 Suppl 4:9-20.
    PMID: 19462319 DOI: 10.1080/09637480802241626
    Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.
    Matched MeSH terms: Physicochemical Phenomena/radiation effects
  14. Haslinda WH, Cheng LH, Chong LC, Noor Aziah AA
    Int J Food Sci Nutr, 2009;60 Suppl 4:232-9.
    PMID: 19449278 DOI: 10.1080/09637480902915525
    Flour was prepared from peeled and unpeeled banana Awak ABB. Samples prepared were subjected to analysis for determination of chemical composition, mineral, dietary fibre, starch and total phenolics content, antioxidant activity and pasting properties. In general, flour prepared from unpeeled banana was found to show enhanced nutrition values with higher contents of mineral, dietary fibre and total phenolics. Hence, flour fortified with peel showed relatively higher antioxidant activity. On the other hand, better pasting properties were shown when banana flour was blended with peel. It was found that a relatively lower pasting temperature, peak viscosity, breakdown, final viscosity and setback were evident in a sample blended with peel.
    Matched MeSH terms: Physicochemical Phenomena
  15. Babji AS, Chin SY, Seri Chempaka MY, Alina AR
    Int J Food Sci Nutr, 1998 Sep;49(5):319-26.
    PMID: 10367000
    Four formulations were processed into frankfurters with different ratios of mechanically deboned chicken meat (MDCM) and cooked chicken skin (CCS) i.e. 80/0, 70/10, 60/20 and 50/30. The products were evaluated for proximate composition, cholesterol content, colour; 'L' value (lightness) and 'a' value (redness), percentage of cooking loss, physical measurements (shearforce-kgf and folding test), thiobarbituric acid value (TBA) and taste panel evaluation. The increment of CCS in the frankfurters increased the contents of moisture, ash, protein, fat, cholesterol, the lightness ('L' value) and redness ('a' value). After 3 months of frozen storage, the increment continued except for the moisture contents for formulations with 20 and 30% CCS. The lipid oxidation (TBA value) and cooking loss were lowered in formulations with CCS. After 3 months of frozen storage, TBA value decreased, while the cooking loss increased for all the formulations. The addition of CCS increased hardness of the frankfurters but affected folding ability, with formulation with 10% CCS scoring better grade. Sensory evaluation was carried out using 30 untrained panelists to evaluate aroma, colour, appearance, hardness, juiciness, chicken taste, oily taste, rancid taste and overall acceptance of the products. The addition of CCS in the frankfurters at 10 and 20% resulted in products with taste and texture that were acceptable after 3 months of frozen storage.
    Matched MeSH terms: Physicochemical Phenomena
  16. Ramli NA, Wong TW
    Int J Pharm, 2011 Jan 17;403(1-2):73-82.
    PMID: 20974238 DOI: 10.1016/j.ijpharm.2010.10.023
    This study investigated critical physicochemical attributes of low (LV), medium (MV) and high molecular weight (HV) sodium carboxymethylcellulose (SCMC) scaffolds in partial thickness wound healing. SCMC scaffolds were prepared by solvent-evaporation technique. Their in vitro erosion, moisture affinity, morphology, tensile strength, polymer molecular weight and carboxymethyl substitution, and in vivo wound healing profiles were determined. Inferring from rat wound size, re-epithelialization and histological profiles, wound healing progressed with HV scaffold>LV-MV scaffold>control with no scaffold. The transepidermal water loss (TEWL) from wound of rats treated by control>HV scaffold>LV-MV scaffold. HV scaffold had the highest tensile strength of all matrices and was resistant to erosion in simulated wound fluid. In spite of constituting small nanopores, it afforded a substantial TEWL than MV and LV scaffolds from wound across an intact matrix through its low moisture affinity characteristics. The HV scaffold can protect moisture loss without its excessive accumulation at wound bed which hindered re-epithelialization process. Regulation of transepidermal water movement and wound healing by scaffolds was governed by SCMC molecular weight instead of its carboxymethyl substitution degree or matrix pore size distribution, with large molecular weight HV preferred over lower molecular weight samples.
    Matched MeSH terms: Physicochemical Phenomena
  17. Bukhari SN, Jantan I, Unsal Tan O, Sher M, Naeem-Ul-Hassan M, Qin HL
    J Agric Food Chem, 2014 Jun 18;62(24):5538-47.
    PMID: 24901506 DOI: 10.1021/jf501145b
    Hyperpigmentation in human skin and enzymatic browning in fruits, which are caused by tyrosinase enzyme, are not desirable. Investigations in the discovery of tyrosinase enzyme inhibitors and search for improved cytotoxic agents continue to be an important line in drug discovery and development. In present work, a new series of 30 compounds bearing α,β-unsaturated carbonyl moiety was designed and synthesized following curcumin as model. All compounds were evaluated for their effects on human cancer cell lines and mushroom tyrosinase enzyme. Moreover, the structure-activity relationships of these compounds are also explained. Molecular modeling studies of these new compounds were carried out to explore interactions with tyrosinase enzyme. Synthetic curcumin-like compounds (2a-b) were identified as potent anticancer agents with 81-82% cytotoxicity. Five of these newly synthesized compounds (1a, 8a-b, 10a-b) emerged to be the potent inhibitors of mushroom tyrosinase, providing further insight into designing compounds useful in fields of food, health, and agriculture.
    Matched MeSH terms: Physicochemical Phenomena
  18. Anarjan N, Tan CP, Ling TC, Lye KL, Malmiri HJ, Nehdi IA, et al.
    J Agric Food Chem, 2011 Aug 24;59(16):8733-41.
    PMID: 21726079 DOI: 10.1021/jf201314u
    A simplex centroid mixture design was used to study the interactions between two chosen solvents, dichloromethane (DCM) and acetone (ACT), as organic-phase components in the formation and physicochemical characterization and cellular uptake of astaxanthin nanodispersions produced using precipitation and condensation processes. Full cubic or quadratic regression models with acceptable determination coefficients were obtained for all of the studied responses. Multiple-response optimization predicted that the organic phase with 38% (w/w) DCM and 62% (w/w) ACT yielded astaxanthin nanodispersions with the minimum particle size (106 nm), polydispersity index (0.191), and total astaxanthin loss (12.7%, w/w) and the maximum cellular uptake (2981 fmol/cell). Astaxanthin cellular uptake from the produced nanodispersions also showed a good correlation with their particle size distributions and astaxanthin trans/cis isomerization ratios. The absence of significant (p > 0.05) differences between the experimental and predicted values of the response variables confirmed the adequacy of the fitted models.
    Matched MeSH terms: Physicochemical Phenomena
  19. Kuan YH, Bhat R, Senan C, Williams PA, Karim AA
    J Agric Food Chem, 2009 Oct 14;57(19):9154-9.
    PMID: 19757813 DOI: 10.1021/jf9015625
    The impact of ultraviolet (UV) irradiation on the physicochemical and functional properties of gum arabic was investigated. Gum arabic samples were exposed to UV irradiation for 30, 60, 90, and 120 min; gum arabic was also treated with formaldehyde for comparison. Molecular weight analysis using gel permeation chromatography indicated that no significant changes occurred on the molecular structure on the samples exposed to UV irradiation. Free amino group analysis indicated that mild UV irradiation (30 min) could induce cross-linking on gum arabic; this result was comparable with that of samples treated with formaldehyde. However, viscosity break down was observed for samples exposed to UV irradiation for longer times (90 and 120 min). All irradiated and formaldehyde-treated samples exhibited better emulsification properties than unirradiated samples. These results indicate that UV-irradiated gum arabic could be a better emulsifier than the native (unmodified) gum arabic and could be exploited commercially.
    Matched MeSH terms: Physicochemical Phenomena
  20. Chan HT, Bhat R, Karim AA
    J Agric Food Chem, 2009 Jul 8;57(13):5965-70.
    PMID: 19489606 DOI: 10.1021/jf9008789
    The effects of oxidation by ozone gas on some physicochemical and functional properties of starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs). Carboxyl and carbonyl contents increased markedly in all starches with increasing OGTs. Oxidation significantly decreased the swelling power of oxidized sago and tapioca starches but increased that of oxidized corn starch. The solubility of tapioca starch decreased and sago starch increased after oxidation. However, there was an insignificant changed in the solubility of oxidized corn starch. Intrinsic viscosity [eta] of all oxidized starches decreased significantly, except for tapioca starch oxidized at 5 min OGT. Pasting properties of the oxidized starches followed different trends as OGTs increased. These results show that under similar conditions of ozone treatment, the extent of starch oxidation varies among different types of starch.
    Matched MeSH terms: Physicochemical Phenomena
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