How to cite this paper
El-Aswad, A., Fouad, M., Badawy, M & Aly, M. (2024). Modeling study of adsorption isotherms of chlorantraniliprole and dinotefuran on soil.Current Chemistry Letters, 13(3), 503-514.
Refrences
1. El-Aswad A. F. (2007) Effect of organic amendments on aldicarb sorption–desorption and soil-bound residue. J. Appl. Sci. Res., 3 (11) 1437-1448.
2. Fouad M. R. (2023) Effect of Temperature and Soil Type on the Adsorption and Desorption Isotherms of Thiamethoxam Using Freundlich Equation. Egypt. J. Chem., 66 (7) 197-207.
3. Führ F., Steffens W., Mittelstaedt W., and Brumhard B. (1991) Lysimeter experiments with 14C-labelled pesticides–an agroecosystem approach. Pesti. Chem., 14: 37-47.
4. Aly M. I., Bakry N., Kishk F., and El‐Sebae A. H. (1980) Carbaryl adsorption on calcium-bentonite and soils. Soil Sci. Soc. Am. J., 44 (6) 1213-1215.
5. Gaber H., Inskeep W., Comfort S., and El‐Attar H. A. (1992) A test of the local equilibrium assumption for adsorption and transport of picloram. Soil Sci. Soc. Am. J., 56 (5) 1392-1400.
6. Fouad M. R., El-Aswad A. F., Aly M. I., and Badawy M. E. I. (2023) Sorption characteristics and thermodynamic parameters of bispyribac-sodium and metribuzin on alluvial soil with difference in particle size and pH value. Curr. Chem. Lett., 12 (3) 545-556.
7. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Effect of soil organic amendments on sorption behavior of two insecticides and two herbicides. Curr. Chem. Lett., 13 (2) 377–390.
8. Olu-Owolabi B. I., Diagboya P. N., and Adebowale, K. O. (2015) Sorption and desorption of fluorene on five tropical soils from different climes. Geoderma, 239: 179-185.
9. Hafez H., and El-Aswad A. F. (2005) Sorption-desorption of Atrazine in soil. Alex. Sci. Exch. J., 26 (1) 41-53.
10. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Effect of pH variation and temperature on pesticides sorption characteristics in calcareous soil. Curr. Chem. Lett., 13 (1) 141-150.
11. Ramasubramanian T., Paramasivam M., Salin K. P., and Jayanthi R. (2012) Dissipation kinetics of chlorantraniliprole in soils of sugarcane ecosystem. Bull. Environ. Contam. Toxicol., 89: 1268-1271.
12. Vijayasree V., Bai H., Beevi S., Mathew T. B., Kumar V., George T., and Xavier G. (2013) Persistence and effects of processing on reduction of chlorantraniliprole residues on cowpea fruits. Bull Environ Contam. Toxicol., 90: 494-498.
13. Fouad M. R., Aly M. I., El-Aswad A. F., and; Badawy M. E. I. (2024) Effect of particles size on adsorption isotherm of chlorantraniliprole, dinotefuran, bispyribac-sodium, and metribuzin into sandy loam soil. Curr. Chem. Lett., 13 (1) 61-72.
14. Wang T. T., Li Y. S., Jiang A. C., Lu M. X., Liu X. J., and Yu X. Y. (2015) Suppression of Chlorantraniliprole Sorption on Biochar in Soil–Biochar Systems. Bull. Environ. Contam. Toxicol., 95: 401-406.
15. Leistra M., Van der Linden A., Boesten J. J. T. I., Tiktak A., and Van den Berg F. (2001) PEARL model for pesticide behaviour and emissions in soil-plant systems: description of the processes in FOCUS PEARL v 1.1. 1. Alterra.
16. Wagenet R., and Rao P. (1985) Basic concepts of modeling pesticide fate in the crop root zone. Weed Sci., 33 (S2) 25-32.
17. El-Aswad A. F., Fouad M. R., Aly M. I., and Badawy M. E. I. (2023) Experimental and modeling study of the fate and behavior of thiobencarb in clay and sandy clay loam soils. Int. J. Environ. Sci. Technol., 1-14.
18. Holvoet K. M., Seuntjens P., and Vanrolleghem P. A. (2007) Monitoring and modeling pesticide fate in surface waters at the catchment scale. Ecol. Modell, 209 (1) 53-64.
19. Soulas G., and Lagacherie B. (2001) Modelling of microbial degradation of pesticides in soils. Biol. Fert. Soils, 33: 551-557.
20. Fouad M. R. (2023) Effect of Soil Amendments on Leaching of Thiamethoxam in Alluvial and Calcareous Soil. Basrah J. Agri. Sci., 36 (1) 164-172.
21. Samarghandi M., Hadi M., Moayedi S., and BARJESTEH A. F. (2009) Two-parameter isotherms of methyl orange sorption by pinecone derived activated carbon. J. Environ. Health Sci. Eng., 6: 285-294.
22. Fouad M. F., Badawy M. E. I., El-Aswad A. F., and Aly M. I. (2023) Experimental modeling design to study the effect of different soil treatments on the dissipation of metribuzin herbicide with effect on dehydrogenase activity. Curr Chem Lett., 12 (2) 383-396.
23. Abdel-Raheem S. A., Fouad M. R., Gad M. A., El-Dean A. M. K., and Tolba M. S. (2023) Environmentally green synthesis and characterization of some novel bioactive pyrimidines with excellent bioefficacy and safety profile towards soil organisms. J. Environ. Chem. Eng., 11 (5) 110839.
24. Fouad M. R. (2023) Effect of peat, compost, and charcoal on transport of fipronil in clay loam soil and sandy clay loam soil. Curr. Chem. Lett., 12 (2) 281-288.
25. El-Aswad A. F., Fouad M. R, Badawy M. E., and Aly, M. I. (2023) Effect of calcium carbonate content on potential pesticide adsorption and desorption in calcareous soil. Commun. Soil Sci. Plant Anal.,54: 1379-1387.
26. Sun Y., Clemens S. C., An Z., and Yu Z. (2006) Astronomical timescale and palaeoclimatic implication of stacked 3.6-Myr monsoon records from the Chinese Loess Plateau. Quat. Sci. Rev., 25 (1-2) 33-48.
27. Hamdaoui O., and Naffrechoux, E. (2007) Modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon: Part I. Two-parameter models and equations allowing determination of thermodynamic parameters. J. Hazar. Mat., 147 (1-2) 381-394.
28. Kumar K. V., and Sivanesan S. (2006) Isotherm parameters for basic dyes onto activated carbon: Comparison of linear and non-linear method. J. Hazar. Mat., 129 (1-3) 147-150.
29. Giles C. (1960) Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms and in measurement of specific surface areas of solids. J. Chem. Soci., 786: 3973-3993.
30. Singh N., and Singh S. (2015) Adsorption and leaching behaviour of bispyribac-sodium in soils. Bull. Environ. Contam. Toxicol., 94: 125-128.
31. Temkin M. I. (1941) Adsorption equilibrium and the kinetics of processes on nonhomogeneous surfaces and in the interaction between adsorbed molecules. Zh. Fiz. Chim., 15: 296-332.
32. Dubinin M., and Radushkevich L. (1947) Equation of the characteristic curve of activated charcoal. Chem. Zentr., 1: 875.
33. Elovich S. Y., and Larinov O. (1962) Theory of adsorption from solutions of non electrolytes on solid (I) equation adsorption from solutions and the analysis of its simplest form,(II) verification of the equation of adsorption isotherm from solutions. Izv. Akad. Nauk. SSSR, Otd. Khim. Nauk, 2 (2) 209-216.
34. Fowler R., and Guggenheim E. (1939) Statistical Thermodynamics (Cambridge University, Cambridge, 1939), Chap.
35. Kiselev A. (1958) Vapor adsorption in the formation of adsorbate molecule complexes on the surface. Kolloid. Zhur., 20: 338-348.
36. Jovanovic D. (1969) Physical adsorption of gases. I. Isotherms for monolayer and multilayer adsorption. Kolloid-Zeitschrift and Zeitschrift Fur Polymere, 235: 1203-1213.
37. Harkins W. D., and Jura G. (1943) An adsorption method for the determination of the area of a solid without the assumption of a molecular area, and the area occupied by nitrogen molecules on the surfaces of solids. J. Chem. Physics., 11 (9) 431-432.
38. Halsey G. (1948) Physical adsorption on non‐uniform surfaces. J. Chem. Physics., 16 (10) 931-937.
39. Shanavas S., Salahuddin Kunju A., and Tresa Varghese H. (2011) Comparison of Langmuir and Harkins-Jura Adsorption Isotherms for the Determination of Surface Area of Solids. Oriental J Chem., 27 (1) 245.
40. Wang T. T., Cheng J., Liu X. J., Jiang W., Zhang C. L., and Yu X. Y. (2012) Effect of biochar amendment on the bioavailability of pesticide chlorantraniliprole in soil to earthworm. Ecotoxicol. Environ. Safety, 83: 96-101.
41. Tatarková V., Hiller E., and Vaculík M. (2013) Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy) acetic acid and the growth of sunflower (Helianthus annuus L.). Ecotoxicol. Environ. Safety, 92: 215-221.
42. Kurwadkar S., Wheat R., McGahan D. G., and Mitchell F. (2014) Evaluation of leaching potential of three systemic neonicotinoid insecticides in vineyard soil. J. Contam. Hydrol., 170: 86-94.
43. Ismail B., Enoma A., Cheah U. B., Lum K. Y., and Malik Z. (2002) Adsorption, desorption, and mobility of two insecticides in Malaysian agricultural soils. J. Environ. Sci. Health Part B, 37 (4) 355-364.
44. El-Aswad A. F., Aly M. I., Fouad M. R., and Badawy M. E. I. (2019) Adsorption and thermodynamic parameters of chlorantraniliprole and dinotefuran on clay loam soil with difference in particle size and pH. J. Environ. Sci. Health Part B, 54 (6) 475-488.
45. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Impact of organic amendments addition to sandy clay loam soil and sandy loam soil on leaching process of chlorantraniliprole insecticide and bispyribac-sodium herbicide. Curr. Chem. Lett., 13 (2) 277–286.
46. Fouad M. R. (2023) Physical characteristics and Freundlich model of adsorption and desorption isotherm for fipronil in six types of Egyptian soil. Curr. Chem. Lett., 12 (1) 207-216.
47. Fouad M. R. (2023) Validation of adsorption-desorption kinetic models for fipronil and thiamethoxam agrichemicals on three types of Egyptian soils. Egypt. J. Chem., 66 (4) 219-222.
48. Fouad M. R., El-Aswad A. F., Badawy M. E. and Aly M. I. (2019) Adsorption isotherms modeling of herbicides bispyribac-sodium and metribuzin on two common Egyptian soil types. J. Agric. Environ. Vet. Sci., 3 (2).
49. Aly M. I., Fouad M. R., Abou-Elnasr H. S., and El-Aswad A. F. (2021) Comparison of Dissipation Kinetics and Residual Behaviour for Fenitrothion Insecticide and Thiobencarb Herbicide in Clay Soil. Alex. J. Agri. Sci., 66 (1) 1-11.
50. Fouad M. R., El-Aswad A. F., and Aly M. I. (2022) Acute toxicity, biochemical and histological of fenitrothion and thiobencarb on fish Nile tilapia (Oreochromis niloticus). Nus. Biosci., 14 (2).
51. Fouad M. R. (2022) Spectrophotometric detection and quantification limits of fipronil and neonicotinoids in acetonitrile. Int. J. Food Sci. Nutr. Health Fam. Stud., 3 (1) 106-123.
52. El-Aswad A. F., Fouad M. R., and Aly M. I. (2023) Assessment of the acute toxicity of agrochemicals on earthworm (Aporrectodea caliginosa) using filter paper contact and soil mixing tests. Asian J. Agri., 7(1).
53. Abd-Eldaim F. A., Farroh K. Y., Safina F. S., Fouad M. R., Darwish O. S., Emam S. S., and Abdel-Halim K. Y. (2023) Phytotoxic effects of ımidacloprid and its nano-form on the cucumber plants under greenhouse condition and their toxicity on HepG2 cell line. Arch. Phytopathol. Pflanzenschutz., 1-20.
2. Fouad M. R. (2023) Effect of Temperature and Soil Type on the Adsorption and Desorption Isotherms of Thiamethoxam Using Freundlich Equation. Egypt. J. Chem., 66 (7) 197-207.
3. Führ F., Steffens W., Mittelstaedt W., and Brumhard B. (1991) Lysimeter experiments with 14C-labelled pesticides–an agroecosystem approach. Pesti. Chem., 14: 37-47.
4. Aly M. I., Bakry N., Kishk F., and El‐Sebae A. H. (1980) Carbaryl adsorption on calcium-bentonite and soils. Soil Sci. Soc. Am. J., 44 (6) 1213-1215.
5. Gaber H., Inskeep W., Comfort S., and El‐Attar H. A. (1992) A test of the local equilibrium assumption for adsorption and transport of picloram. Soil Sci. Soc. Am. J., 56 (5) 1392-1400.
6. Fouad M. R., El-Aswad A. F., Aly M. I., and Badawy M. E. I. (2023) Sorption characteristics and thermodynamic parameters of bispyribac-sodium and metribuzin on alluvial soil with difference in particle size and pH value. Curr. Chem. Lett., 12 (3) 545-556.
7. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Effect of soil organic amendments on sorption behavior of two insecticides and two herbicides. Curr. Chem. Lett., 13 (2) 377–390.
8. Olu-Owolabi B. I., Diagboya P. N., and Adebowale, K. O. (2015) Sorption and desorption of fluorene on five tropical soils from different climes. Geoderma, 239: 179-185.
9. Hafez H., and El-Aswad A. F. (2005) Sorption-desorption of Atrazine in soil. Alex. Sci. Exch. J., 26 (1) 41-53.
10. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Effect of pH variation and temperature on pesticides sorption characteristics in calcareous soil. Curr. Chem. Lett., 13 (1) 141-150.
11. Ramasubramanian T., Paramasivam M., Salin K. P., and Jayanthi R. (2012) Dissipation kinetics of chlorantraniliprole in soils of sugarcane ecosystem. Bull. Environ. Contam. Toxicol., 89: 1268-1271.
12. Vijayasree V., Bai H., Beevi S., Mathew T. B., Kumar V., George T., and Xavier G. (2013) Persistence and effects of processing on reduction of chlorantraniliprole residues on cowpea fruits. Bull Environ Contam. Toxicol., 90: 494-498.
13. Fouad M. R., Aly M. I., El-Aswad A. F., and; Badawy M. E. I. (2024) Effect of particles size on adsorption isotherm of chlorantraniliprole, dinotefuran, bispyribac-sodium, and metribuzin into sandy loam soil. Curr. Chem. Lett., 13 (1) 61-72.
14. Wang T. T., Li Y. S., Jiang A. C., Lu M. X., Liu X. J., and Yu X. Y. (2015) Suppression of Chlorantraniliprole Sorption on Biochar in Soil–Biochar Systems. Bull. Environ. Contam. Toxicol., 95: 401-406.
15. Leistra M., Van der Linden A., Boesten J. J. T. I., Tiktak A., and Van den Berg F. (2001) PEARL model for pesticide behaviour and emissions in soil-plant systems: description of the processes in FOCUS PEARL v 1.1. 1. Alterra.
16. Wagenet R., and Rao P. (1985) Basic concepts of modeling pesticide fate in the crop root zone. Weed Sci., 33 (S2) 25-32.
17. El-Aswad A. F., Fouad M. R., Aly M. I., and Badawy M. E. I. (2023) Experimental and modeling study of the fate and behavior of thiobencarb in clay and sandy clay loam soils. Int. J. Environ. Sci. Technol., 1-14.
18. Holvoet K. M., Seuntjens P., and Vanrolleghem P. A. (2007) Monitoring and modeling pesticide fate in surface waters at the catchment scale. Ecol. Modell, 209 (1) 53-64.
19. Soulas G., and Lagacherie B. (2001) Modelling of microbial degradation of pesticides in soils. Biol. Fert. Soils, 33: 551-557.
20. Fouad M. R. (2023) Effect of Soil Amendments on Leaching of Thiamethoxam in Alluvial and Calcareous Soil. Basrah J. Agri. Sci., 36 (1) 164-172.
21. Samarghandi M., Hadi M., Moayedi S., and BARJESTEH A. F. (2009) Two-parameter isotherms of methyl orange sorption by pinecone derived activated carbon. J. Environ. Health Sci. Eng., 6: 285-294.
22. Fouad M. F., Badawy M. E. I., El-Aswad A. F., and Aly M. I. (2023) Experimental modeling design to study the effect of different soil treatments on the dissipation of metribuzin herbicide with effect on dehydrogenase activity. Curr Chem Lett., 12 (2) 383-396.
23. Abdel-Raheem S. A., Fouad M. R., Gad M. A., El-Dean A. M. K., and Tolba M. S. (2023) Environmentally green synthesis and characterization of some novel bioactive pyrimidines with excellent bioefficacy and safety profile towards soil organisms. J. Environ. Chem. Eng., 11 (5) 110839.
24. Fouad M. R. (2023) Effect of peat, compost, and charcoal on transport of fipronil in clay loam soil and sandy clay loam soil. Curr. Chem. Lett., 12 (2) 281-288.
25. El-Aswad A. F., Fouad M. R, Badawy M. E., and Aly, M. I. (2023) Effect of calcium carbonate content on potential pesticide adsorption and desorption in calcareous soil. Commun. Soil Sci. Plant Anal.,54: 1379-1387.
26. Sun Y., Clemens S. C., An Z., and Yu Z. (2006) Astronomical timescale and palaeoclimatic implication of stacked 3.6-Myr monsoon records from the Chinese Loess Plateau. Quat. Sci. Rev., 25 (1-2) 33-48.
27. Hamdaoui O., and Naffrechoux, E. (2007) Modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon: Part I. Two-parameter models and equations allowing determination of thermodynamic parameters. J. Hazar. Mat., 147 (1-2) 381-394.
28. Kumar K. V., and Sivanesan S. (2006) Isotherm parameters for basic dyes onto activated carbon: Comparison of linear and non-linear method. J. Hazar. Mat., 129 (1-3) 147-150.
29. Giles C. (1960) Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms and in measurement of specific surface areas of solids. J. Chem. Soci., 786: 3973-3993.
30. Singh N., and Singh S. (2015) Adsorption and leaching behaviour of bispyribac-sodium in soils. Bull. Environ. Contam. Toxicol., 94: 125-128.
31. Temkin M. I. (1941) Adsorption equilibrium and the kinetics of processes on nonhomogeneous surfaces and in the interaction between adsorbed molecules. Zh. Fiz. Chim., 15: 296-332.
32. Dubinin M., and Radushkevich L. (1947) Equation of the characteristic curve of activated charcoal. Chem. Zentr., 1: 875.
33. Elovich S. Y., and Larinov O. (1962) Theory of adsorption from solutions of non electrolytes on solid (I) equation adsorption from solutions and the analysis of its simplest form,(II) verification of the equation of adsorption isotherm from solutions. Izv. Akad. Nauk. SSSR, Otd. Khim. Nauk, 2 (2) 209-216.
34. Fowler R., and Guggenheim E. (1939) Statistical Thermodynamics (Cambridge University, Cambridge, 1939), Chap.
35. Kiselev A. (1958) Vapor adsorption in the formation of adsorbate molecule complexes on the surface. Kolloid. Zhur., 20: 338-348.
36. Jovanovic D. (1969) Physical adsorption of gases. I. Isotherms for monolayer and multilayer adsorption. Kolloid-Zeitschrift and Zeitschrift Fur Polymere, 235: 1203-1213.
37. Harkins W. D., and Jura G. (1943) An adsorption method for the determination of the area of a solid without the assumption of a molecular area, and the area occupied by nitrogen molecules on the surfaces of solids. J. Chem. Physics., 11 (9) 431-432.
38. Halsey G. (1948) Physical adsorption on non‐uniform surfaces. J. Chem. Physics., 16 (10) 931-937.
39. Shanavas S., Salahuddin Kunju A., and Tresa Varghese H. (2011) Comparison of Langmuir and Harkins-Jura Adsorption Isotherms for the Determination of Surface Area of Solids. Oriental J Chem., 27 (1) 245.
40. Wang T. T., Cheng J., Liu X. J., Jiang W., Zhang C. L., and Yu X. Y. (2012) Effect of biochar amendment on the bioavailability of pesticide chlorantraniliprole in soil to earthworm. Ecotoxicol. Environ. Safety, 83: 96-101.
41. Tatarková V., Hiller E., and Vaculík M. (2013) Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy) acetic acid and the growth of sunflower (Helianthus annuus L.). Ecotoxicol. Environ. Safety, 92: 215-221.
42. Kurwadkar S., Wheat R., McGahan D. G., and Mitchell F. (2014) Evaluation of leaching potential of three systemic neonicotinoid insecticides in vineyard soil. J. Contam. Hydrol., 170: 86-94.
43. Ismail B., Enoma A., Cheah U. B., Lum K. Y., and Malik Z. (2002) Adsorption, desorption, and mobility of two insecticides in Malaysian agricultural soils. J. Environ. Sci. Health Part B, 37 (4) 355-364.
44. El-Aswad A. F., Aly M. I., Fouad M. R., and Badawy M. E. I. (2019) Adsorption and thermodynamic parameters of chlorantraniliprole and dinotefuran on clay loam soil with difference in particle size and pH. J. Environ. Sci. Health Part B, 54 (6) 475-488.
45. Fouad M. R., El-Aswad A. F., Badawy M. E. I., and Aly M. I. (2024) Impact of organic amendments addition to sandy clay loam soil and sandy loam soil on leaching process of chlorantraniliprole insecticide and bispyribac-sodium herbicide. Curr. Chem. Lett., 13 (2) 277–286.
46. Fouad M. R. (2023) Physical characteristics and Freundlich model of adsorption and desorption isotherm for fipronil in six types of Egyptian soil. Curr. Chem. Lett., 12 (1) 207-216.
47. Fouad M. R. (2023) Validation of adsorption-desorption kinetic models for fipronil and thiamethoxam agrichemicals on three types of Egyptian soils. Egypt. J. Chem., 66 (4) 219-222.
48. Fouad M. R., El-Aswad A. F., Badawy M. E. and Aly M. I. (2019) Adsorption isotherms modeling of herbicides bispyribac-sodium and metribuzin on two common Egyptian soil types. J. Agric. Environ. Vet. Sci., 3 (2).
49. Aly M. I., Fouad M. R., Abou-Elnasr H. S., and El-Aswad A. F. (2021) Comparison of Dissipation Kinetics and Residual Behaviour for Fenitrothion Insecticide and Thiobencarb Herbicide in Clay Soil. Alex. J. Agri. Sci., 66 (1) 1-11.
50. Fouad M. R., El-Aswad A. F., and Aly M. I. (2022) Acute toxicity, biochemical and histological of fenitrothion and thiobencarb on fish Nile tilapia (Oreochromis niloticus). Nus. Biosci., 14 (2).
51. Fouad M. R. (2022) Spectrophotometric detection and quantification limits of fipronil and neonicotinoids in acetonitrile. Int. J. Food Sci. Nutr. Health Fam. Stud., 3 (1) 106-123.
52. El-Aswad A. F., Fouad M. R., and Aly M. I. (2023) Assessment of the acute toxicity of agrochemicals on earthworm (Aporrectodea caliginosa) using filter paper contact and soil mixing tests. Asian J. Agri., 7(1).
53. Abd-Eldaim F. A., Farroh K. Y., Safina F. S., Fouad M. R., Darwish O. S., Emam S. S., and Abdel-Halim K. Y. (2023) Phytotoxic effects of ımidacloprid and its nano-form on the cucumber plants under greenhouse condition and their toxicity on HepG2 cell line. Arch. Phytopathol. Pflanzenschutz., 1-20.