Collect. Czech. Chem. Commun.
1974, 39, 3773-3781
https://doi.org/10.1135/cccc19743773
6-Azauridine-5'-uronic acid and related compounds: Synthesis and binding to proteins
H. Pischel, A. Holý and G. Wagner
Individual author index pages
Other CCCC articles of these authors
- H. Dvořáková, A. Holý, M. Masojídková, I. Votruba, J. Balzarini, R. Snoeck and E. De Clercq
Synthesis and antiviral activity of acyclic nucleoside and nucleotide derivatives of 8-azaadenine
1993, Vol. 58, Special Issue, pp. S253–S255 [Abstract] - D. Hocková, A. Holý and H. Dvořáková
Acyclic nucleoside analogues derived from 2-azapurines
1993, Vol. 58, Special Issue, pp. S250–S252 [Abstract] - Z. Janeba, H. Dvořáková and A. Holý
Studies on acyclic anhydro nucleosides. Formation and reactivity of seven-membered cyclic structures
1993, Vol. 58, Special Issue, pp. S247–S249 [Abstract] - K. Juricová, A. Holý, S. Smrčková, M. Spassova and H. Dvořáková
Synthesis of base-modified "abbreviated" acyclic NAD-analogues
1993, Vol. 58, Special Issue, pp. S244–S246 [Abstract] - J. Brokeš and A. Holý
Synthesis of 5'-O-phosphonomethyl derivatives of biologically active nucleosides
1990, Vol. 55, Special Issue, pp. S125–S128 [Abstract] - H. Dvořáková, A. Holý, R. Snoeck, J. Balzarini and E. De Clercq
Acyclic nucleoside and nucleotide analogues derived from 1-deaza and 3-deazaadenine
1990, Vol. 55, Special Issue, pp. S113–S116 [Abstract] - M. Spassova and A. Holý
N-(3-Azido-2-hydroxypropyl) derivatives of purine and pyrimidine bases
1990, Vol. 55, Special Issue, pp. S65–S68 [Abstract] - D. Cech, H. Beerbaum and A. Holý
A simple synthesis of 5-fluoro-2-pyrimidinone and its N1-substituted derivatives
1977, Vol. 42, Issue 9, pp. 2694–2700 [Abstract] - V. Pačes, I. Rosenberg, M. Kamínek and A. Holý
Metabolism of cytokinins in rape seedlings (Brassica napus L.)
1977, Vol. 42, Issue 8, pp. 2452–2458 [Abstract] - A. Holý and H. Pischel
Preparation of 5'-O-carboxymethyluridine and its 5-halo derivatives
1977, Vol. 42, Issue 7, pp. 2261–2265 [Abstract] - D. Cech and A. Holý
Preparation of 2-pyrimidinone nucleosides from uracil nucleosides
1977, Vol. 42, Issue 7, pp. 2246–2260 [Abstract] - A. Holý
Preparation of acyl derivatives of pyrimidin-2-one nucleosides by the silyl variant of the Hilbert-Johnson reaction
1977, Vol. 42, Issue 3, pp. 902–908 [Abstract] - J. Doskočil and A. Holý
Specificity of purine nucleoside phosphorylase from Escherichia coli
1977, Vol. 42, Issue 1, pp. 370–383 [Abstract] - D. Cech and A. Holý
Preparation of some 2'-deoxy-5-fluorouridine derivatives by a direct fluorination
1976, Vol. 41, Issue 11, pp. 3335–3342 [Abstract] - A. Holý and M. Plšek
Substrate specificity of rape pollen 3'-nucleotidase (Brassica napus)
1976, Vol. 41, Issue 8, pp. 2433–2439 [Abstract] - A. Holý
New synthesis of ribonucleoside carbocyclic analogues
1976, Vol. 41, Issue 7, pp. 2096–2109 [Abstract] - A. Holý and M. Plšek
Properties of ribonuclease, phosphodiesterase, and decyclizing phosphodiesterase from rape (Brassica napus L.) pollen
1976, Vol. 41, Issue 5, pp. 1612–1626 [Abstract] - A. Holý, M. Plšek and O. Haragsim
Identification of main nucleolytic activities of the bee-gathered rape pollen (Brassica napus L.)
1976, Vol. 41, Issue 5, pp. 1598–1611 [Abstract] - A. Holý
Preparation of substituted (±)-5t-hydroxymethyl-3t-aminocyclopentane-1r,2c-diol derivatives related to carbocyclic ribonucleoside analogues
1976, Vol. 41, Issue 2, pp. 647–665 [Abstract] - A. M. Kritzyn and A. Holý
Stereospecific synthesis of β-D-ribopyranosyl nucleoside analogues
1975, Vol. 40, Issue 10, pp. 3211–3219 [Abstract] - H. Pischel, A. Holý, G. Wagner and D. Cech
Carboxymethylated uracil, 2'-deoxyuridine and their 5-fluoro, 5-bromo, and 5-iodo derivatives
1975, Vol. 40, Issue 9, pp. 2689–2699 [Abstract] - V. Uchytilová, A. Holý, D. Cech and J. Gut
Preparation of 2-pyrimidinone and derivatives
1975, Vol. 40, Issue 8, pp. 2347–2352 [Abstract] - A. Holý
Preparation of orotidine, 2'-deoxyorotidine, and related compounds
1975, Vol. 40, Issue 3, pp. 738–752 [Abstract] - A. Holý
Aliphatic analogues of nucleosides, nucleotides, and oligonucleotides
1975, Vol. 40, Issue 1, pp. 187–214 [Abstract] - A. Holý and H. Pischel
Preparation of 5'-O-carboxymethylcytidine and 5'-O-carboxymethyl-1-(β-D-arabinofuranosyl)cytosine
1974, Vol. 39, Issue 12, pp. 3763–3772 [Abstract] - A. Holý
Preparation of 6-methyluridine, 6-ethyluridine, and 2'-deoxy-6-ethyluridine
1974, Vol. 39, Issue 11, pp. 3374–3382 [Abstract] - A. Holý
Reaction of sugar 2-amino[1',2':4,5]oxazolines with substituted alkyl β-halo- and β-alkoxyacrylates
1974, Vol. 39, Issue 11, pp. 3177–3186 [Abstract] - A. Holý and D. Cech
Synthesis of 2'-deoxythymidine, 2'-deoxy-5-fluorouridine, and 2'-deoxy-6-azauridine from ribonucleosides
1974, Vol. 39, Issue 11, pp. 3157–3167 [Abstract] - G. S. Ivanova, A. Holý, E. Zelinková, S. I. Bezborodova, N. M. Abrosimova-Amelyanchik and R. I. Tatarskaya
Substrate specificity of some microbial guanyloribonucleases
1974, Vol. 39, Issue 10, pp. 2986–2997 [Abstract] - A. Holý and I. Votruba
Substrate specificity of bacterial thymidylate-synthetase
1974, Vol. 39, Issue 6, pp. 1646–1661 [Abstract] - G. S. Ivanova, A. Holý and S. I. Bezborodova
Substrate requirements of some microbial ribonucleases non-specific to natural bases
1974, Vol. 39, Issue 4, pp. 993–1004 [Abstract] - A. Holý, I. Votruba and K. Jošt
S-(Pyrimidin-2-yl)-L-cysteine: Chemical synthesis and biosynthesis in Escherichia coli
1974, Vol. 39, Issue 2, pp. 634–646 [Abstract] - A. Holý
Substrate specificity of spleen acid exonuclease and spleen cyclic phosphodiesterase
1974, Vol. 39, Issue 1, pp. 310–332 [Abstract] - A. Holý
Nucleic acid components and their analogues. CLXII. Preparation of 6-methyl-2'-deoxyuridine and related compounds
1973, Vol. 38, Issue 12, pp. 3912–3931 [Abstract] - R. Wightman and A. Holý
Nucleic acid components and their analogues. CLIX. Synthesis of some 2-pyrimidone nucleosides
1973, Vol. 38, Issue 5, pp. 1381–1397 [Abstract] - A. Holý and Z. Arnold
Nucleic acid components and their analogues. CLVIII. Preparation of some substituted 2-amino- and 2-mercaptopyrimidines from trimethinium salts
1973, Vol. 38, Issue 5, pp. 1371–1380 [Abstract] - V. Pačes and A. Holý
Inhibition of protein synthesis by pyrimidone-(2)-ribofuranoside in Escherichia coli
1973, Vol. 38, Issue 4, pp. 1268–1272 [Abstract] - A. Holý
Nucleic acid components and their analogues. CLVI. Preparation of enantiometric 1-(α-xylofuranosyl), 1-(α-lyxofuranosyl), and 1-(2-deoxy-α-lyxofuranosyl) derivatives of uracil and cytosine
1973, Vol. 38, Issue 2, pp. 428–437 [Abstract] - A. Holý
Nucleic acid components and their analogues. CLV. Mechanism of anomalous opening of the O2,2'-anhydro bond in uracil cyclonucleosides
1973, Vol. 38, Issue 2, pp. 423–427 [Abstract] - A. Holý
Nucleic acid components and their analogues. CLIV. Nucleoside and nucleotide derivatives of α-uridine, 2'-deoxy-α-uridine and 2'-deoxy-α-cytidine, and their affinity towards nucleolytic enzymes
1973, Vol. 38, Issue 1, pp. 100–114 [Abstract] - A. Holý
Nucleic acid components and their analogues. CLIII. Preparation of 2'-deoxy-L-ribonucleosides of the pyrimidine series
1972, Vol. 37, Issue 12, pp. 4072–4087 [Abstract] - H. Pischel, A. Holý and G. Wagner
Glykoside von Heterocyclen XLV. Riboside von Pyrimidonen
1972, Vol. 37, Issue 10, pp. 3475–3482 [Abstract] - I. Votruba, A. Holý and H. Pischel
Inhibition of DNA synthesis in Escherichia coli by 1-(β-D-ribofuranosyl)-2-pyrimidone
1972, Vol. 37, Issue 7, pp. 2213–2220 [Abstract] - A. Holý and Ng. D. Hong
Nucleic acid components and their analogues. CL. Preparation and properties of some nucleoside hydroxyalkanephosphonates
1972, Vol. 37, Issue 6, pp. 2066–2076 [Abstract] - Z. Kučerová, A. Holý and R. W. Bald
Nucleic acid components and their analogues. CXLVIII. Preparation of some nucleotidic derivatives of orotidine
1972, Vol. 37, Issue 6, pp. 2052–2058 [Abstract] - A. Holý
Nucleic acid components and their analogues. CXLVII. Preparation of 5-ethoxycarbonyluridine, 5-carboxyuridine and their nucleotidic derivatives
1972, Vol. 37, Issue 5, pp. 1555–1576 [Abstract] - A. Holý, R. W. Bald and F. Šorm
Nucleic acid components and their analogues. CXLVI. Preparation of some nucleotide derivatives of 6-methyluridine, 3-(β-D-ribofuranosyl)uracil, and 3-(β-D-ribofuranosyl)-6-methyluracil. Investigations of their template activity and behaviour towards some nucleolytic enzymes
1972, Vol. 37, Issue 2, pp. 592–602 [Abstract] - R. W. Bald and A. Holý
Nucleic acid components and their analogues. CXLII. Preparation of 3-(β-D-ribofuranosyl)uracil 2',3'-cyclic phosphate and related compounds and their behaviour towards pancreatic ribonuclease and ribonuclease T2
1971, Vol. 36, Issue 11, pp. 3657–3669 [Abstract] - A. Holý and F. Šorm
Nucleic acid components and their analogues. CXL. Preparation of 5'-L-ribonucleotides, some of their derivatives, and 2'(3')→5'-homooligo-L-ribonucleotides; coding properties of L-ribonucleoside-containing oligonucleotides
1971, Vol. 36, Issue 9, pp. 3282–3299 [Abstract] - A. Holý and R. Bald
Nucleic acid components and their analogues. CXXXVIII. Synthesis of 2',3'-cyclic phosphates derived from some pyrimidine ribonucleosides and their behaviour towards pancreatic ribonuclease and ribonuclease T2
1971, Vol. 36, Issue 8, pp. 2809–2823 [Abstract] - A. Holý, R. W. Bald and Ng. D. Hong
Nucleic acid components and their analogues. CXXXVII. Preparation and properties of some N-(2-hydroxyethyl) derivatives of ribonucleosides and nucleotides
1971, Vol. 36, Issue 7, pp. 2658–2676 [Abstract] - A. Holý and Ng. D. Hong
Synthesis of ribonucleoside 5'-O-hydroxymethanephosphonates
1971, Vol. 36, Issue 1, pp. 316–317 [Abstract] - A. Holý
Oligonucleotidic compounds. XXXVIII. Synthesis of diribonucleoside phosphates and triribonucleoside diphosphates derived from adenosine 3'-phosphate and guanosine 3'-phosphate: A general approach to the synthesis of oligonucleotides
1970, Vol. 35, Issue 12, pp. 3686–3711 [Abstract] - H. Pischel and A. Holý
Oligonucleotid-Verbindungen XXXVII. Synthese einiger Nucleotid-Derivate von 1-(β-D-Ribofuranosyl)pyrimidon-(2) und 3-(β-D-Ribofuranosyl)pyrimidon-(4)
1970, Vol. 35, Issue 12, pp. 3584–3596 [Abstract] - A. Holý
Nucleic acid components and their analogues. CXXX. Preparation of nucleotide derivatives of 1'-homouridine and their behaviour towards some nucleolytic enzymes
1970, Vol. 35, Issue 1, pp. 81–88 [Abstract] - A. Holý and J. Žemlička
Oligonucleotidic compounds. XXXV. Reaction of diribonucleoside phosphates with dimethylformamide acetals
1969, Vol. 34, Issue 12, pp. 3921–3935 [Abstract] - A. Holý and F. Šorm
Nucleic acid components and their analogues CXXIX. Synthesis of enantiomeric 2',3'-cyclic phosphates of 9-(α-lyxofuranosyl)adenine and -hypoxanthine and their behaviour towards ribonuclease T1 and T2
1969, Vol. 34, Issue 11, pp. 3523–3532 [Abstract] - A. Holý
Nucleic acid components and their analogues. CXXVIII. Phosphorylation of some thymine 1-pentopyranosyl and 1-hexopyranosyl derivatives by the reaction with triethyl phosphite and hexachloroacetone
1969, Vol. 34, Issue 11, pp. 3510–3522 [Abstract] - A. Holý and F. Šorm
Oligonucleotidic compounds. XXXIV. Preparation of some β-L-ribonucleosides, their 2'(3')-phosphates and 2',3'-cyclic phosphates
1969, Vol. 34, Issue 11, pp. 3383–3401 [Abstract] - A. Holý and J. Žemlička
Oligonucleotidic compounds. XXXIII. A study on hydrolysis of N-dimethylaminomethylenecytidine, -adenosine, -guanosine, and related 2'-deoxy compounds
1969, Vol. 34, Issue 8, pp. 2449–2458 [Abstract] - A. Holý and F. Šorm
Oligonucleotidic compounds. XXXII. Phosphorylation of 1-lyxofuranosyl, 1-xylofuranosyl and 1-arabinofuranosyl derivatives of uracil and thymine with triethyl phosphite and hexachloroacetone
1969, Vol. 34, Issue 7, pp. 1929–1953 [Abstract] - A. Holý
Oligonucleotidic compounds. XXX. Synthesis of some 5'-O-substituted derivatives of guanosine 2',3'-cyclic phosphate and guanylyl-(3'→5')-uridine
1969, Vol. 34, Issue 4, pp. 1261–1277 [Abstract] - A. Holý, S. Chládek and J. Žemlička
Oligonucleotidic compounds. XXIX. Reactions of ribonucleoside 2'(3')-phosphates with dimethylformamide acetals
1969, Vol. 34, Issue 1, pp. 253–271 [Abstract] - H. Pischel and A. Holý
Oligonucleotid-Verbindungen XXVIII. Synthese von (3'→5')-Diribonucleosidphosphaten von 1-(β-D-Ribofuranosyl)-pyridon-(2) und 2-(β-D-Ribofuranosyl)-pyridazon-(3)
1969, Vol. 34, Issue 1, pp. 89–102 [Abstract] - Z. Kučerová, J. Škoda, A. Holý and F. Šorm
Factors affecting the cleavage of adenosine and uridine 5'-phosphites by the venom of Vipera russelli
1968, Vol. 33, Issue 12, pp. 4350–4355 [Abstract] - V. Lisý, J. Škoda, I. Rychlík, J. Smrt, A. Holý and F. Šorm
Changes in coding properties of poly- and oligonucleotides containing 6-azapyrimidine ribonucleosides
1968, Vol. 33, Issue 12, pp. 4111–4119 [Abstract] - D. Grünberger, A. Holý, J. Smrt and F. Šorm
Effect of substitution of halogen or N3-methyl derivatives of uridine for uridine in trinucleotide codons on their recognition by aminoacyl-[14C]-tRNA
1968, Vol. 33, Issue 11, pp. 3858–3865 [Abstract] - A. Holý, J. Smrt and F. Šorm
Oligonucleotidic compounds. XXVII. Synthesis of diribonucleoside phosphates containing 5-halo derivatives of uridine and 3-methyluridine
1968, Vol. 33, Issue 11, pp. 3809–3822 [Abstract] - M. P. Mertes, A. Holý and J. Smrt
Oligonucleotidic compounds. XXVI. Synthesis of uridylyl-(3'→5')-N4-hydroxy-6-azacytidine and N4-hydroxy-6-azacytidylyl-(3'→5')-uridine
1968, Vol. 33, Issue 10, pp. 3313–3323 [Abstract] - A. Holý
Oligonucleotidic compounds. XXIV. Synthesis of 2',3'-cyclic phosphates of inosine, xanthosine, 9-(β-D-ribofuranosyl)-6-mercaptopurine, and 9-(β-D-ribofuranosyl)-2-amino-6-mercaptopurine
1968, Vol. 33, Issue 7, pp. 2245–2256 [Abstract] - H. Pischel and A. Holý
Nucleinsäure-Komponenten und ihre Analoga CXIV. Synthese der 5'-Diphosphate von 1-(β-D-Ribofuranosyl)-pyridon-(2) und 2-(β-D-Ribofuranosyl)-pyridazon-(3)
1968, Vol. 33, Issue 7, pp. 2066–2073 [Abstract] - D. Grünberger, A. Holý and F. Šorm
Synthesis of triribonucleoside diphosphates with ribonuclease T1
1968, Vol. 33, Issue 1, pp. 286–295 [Abstract] - A. Holý
Oligonucleotidic compounds. XXI. Synthesis of (3'→5')-diribonucleoside phosphate 2',3'-cyclic phosphates from unprotected (3'→5')-diribonucleoside phosphates
1968, Vol. 33, Issue 1, pp. 223–231 [Abstract] - A. Holý and H. Pischel
Oligonucleotidic compounds. XX. A general method for the synthesis of 5'-O-phosphorylribonucleoside 2',3'-cyclic phosphates
1967, Vol. 32, Issue 10, pp. 3719–3725 [Abstract] - A. Holý
Nucleic acid components and their analogues. IC. Synthesis of 6-azauridine 5'-methanephosphonate and 6-azauridine (2')3'-methanephosphonate
1967, Vol. 32, Issue 10, pp. 3713–3718 [Abstract] - J. Žemlička and A. Holý
Preparation of N-dimethylaminomethylene derivatives - A new method of a selective substitution of nucleoside amino groups
1967, Vol. 32, Issue 9, pp. 3159–3168 [Abstract] - A. Holý
Nucleic acids components and their analogues. XCV. Synthesis of ribonucleoside 5'-phosphites
1967, Vol. 32, Issue 8, pp. 3064–3067 [Abstract] - A. Holý, J. Smrt and F. Šorm
Oligonucleotidic compounds. XVII. Synthesis of oligonucleotides containing 6-azauridine and 6-azacytidine
1967, Vol. 32, Issue 8, pp. 2980–2997 [Abstract] - D. Grünberger, L. Meissner, A. Holý and F. Šorm
The coding properties of polymers and trinucleoside diphosphates containing 8-azaguanosine
1967, Vol. 32, Issue 7, pp. 2625–2633 [Abstract] - Z. Kučerová, A. Holý, J. Škoda and F. Šorm
Release of inorganic phosphite from nucleoside 5'-phosphites by Russell's viper venom
1967, Vol. 32, Issue 5, pp. 2038–2041 [Abstract] - A. Holý and J. Smrt
Oligonucleotidic compounds. XV. A general approach to the stepwise synthesis of ribooligonucleotides. Synthesis of some triribonucleoside diphosphates
1966, Vol. 31, Issue 9, pp. 3800–3816 [Abstract] - J. Žemlička, S. Chládek, A. Holý and J. Smrt
Oligonucleotidic compounds. XIV. Synthesis of some diribonucleoside phosphates using the N-dimethylaminomethylene derivatives of 2',3'-O-ethoxymethylene ribonucleosides
1966, Vol. 31, Issue 8, pp. 3198–3212 [Abstract] - A. Holý
Nucleic acids components and their analogues. LXXXIV. Synthesis of some derivatives of N1-formyl- and N1,N5-diformylbiuret
1966, Vol. 31, Issue 7, pp. 2973–2977 [Abstract] - A. Holý and F. Šorm
Nucleic acids components and their analogues. LXXXI. A selective synthesis of ribonucleoside-2'(3') phosphites
1966, Vol. 31, Issue 4, pp. 1562–1568 [Abstract] - A. Holý and F. Šorm
Nucleic acids components and their analogues. LXXX. Preparation of nucleoside phosphites by reacion of nucleosides with triphenyl phosphite
1966, Vol. 31, Issue 4, pp. 1544–1561 [Abstract] - A. Holý and J. Smrt
Oligonucleotidic compounds. XI. Synthesis of ribonucleoside-2',3' cyclophosphates from nucleosides via nucleoside 2',3'-phosphites
1966, Vol. 31, Issue 4, pp. 1528–1534 [Abstract] - A. Holý, J. Krupička and Z. Arnold
The polarographic behaviour of polymethinium salts
1965, Vol. 30, Issue 12, pp. 4127–4142 [Abstract] - A. Holý, J. Smrt and F. Šorm
Nucleic acids components and their analogues. LXXI. Oxidation of nucleoside 5'-phosphites on treatment with halo acid derivatives and hexachloroacetone
1965, Vol. 30, Issue 10, pp. 3309–3319 [Abstract] - A. Holý, J. Smrt and F. Šorm
Nucleic acids components and their analogues. LIX. The preparation and properties of nucleoside phosphites
1965, Vol. 30, Issue 5, pp. 1635–1642 [Abstract] - A. Holý and Z. Arnold
The formation of a pyrrole derivative during the reaction of 1-phenyltrimethinium salt with sodium hydride
1965, Vol. 30, Issue 1, pp. 346–348 [Abstract] - A. Holý and Z. Arnold
Synthetic reactions of dimethylformamide. XXI. The formation of aromatic compounds during the formylation reactions
1965, Vol. 30, Issue 1, pp. 53–60 [Abstract] - Z. Arnold and A. Holý
Synthetic reactions of dimethylformamide. XX. Preparation of some vinylogous polymethinium systems
1965, Vol. 30, Issue 1, pp. 47–52 [Abstract] - Z. Arnold and A. Holý
The preparation of substituted pentamethinium salts
1965, Vol. 30, Issue 1, pp. 40–46 [Abstract] - A. Holý, N. Ch. Spasovska and J. Smrt
Synthesis of 6-azauridylyl-(5'→5')-6-azauridine and P1,P2-di-(6-azauridylyl-5')-pyrophosphate
1964, Vol. 29, Issue 10, pp. 2567–2570 [Abstract] - Z. Arnold and A. Holý
Synthetic reactions of dimethylformamide. XVIII. Reactivity of methyl groups in polymethinium salts
1963, Vol. 28, Issue 8, pp. 2040–2046 [Abstract] - Z. Arnold and A. Holý
Synthetische Reaktionen von Dimethylformamid XVII. Darstellung von Acylmalondialdehyden durch Formylierung von Trimethiniumsalzen
1963, Vol. 28, Issue 4, pp. 869–881 [Abstract] - Z. Arnold and A. Holý
Synthetic reactions of dimethylformamide. XIV. Some new findings on adducts of the Vilsmeier-Haack type
1962, Vol. 27, Issue 12, pp. 2886–2897 [Abstract] - A. Holý and A. Vystrčil
Studie der Aurone II. Über die Reaktivität der Carbonylgruppe in Auronen
1962, Vol. 27, Issue 8, pp. 1861–1869 [Abstract] - Z. Arnold and A. Holý
Synthetic reactions of dimethylformamide. XIII. β-Bromoacraldehydes
1961, Vol. 26, Issue 12, pp. 3059–3073 [Abstract] - A. Holý
Studie der Aurone I. Polarographisches Verhalten des 2-Benzalcumaranons-(3) vorläufige Mitteilung
1958, Vol. 23, Issue 11, pp. 2131–2134 [Abstract]
