Chinese Journal of Chemistry

Cover image for Chinese Journal of Chemistry

August, 2010

Volume 28, Issue 8

Pages 1317–1509

  1. Communication

    1. Top of page
    2. Communication
    3. Full Papers
    4. Note
    1. Effect of Electronic Structures of Enantiomers of Ruthenium(II) Polypyridyl Complexes on DNA Binding Behaviors (pages 1317–1321)

      Haimei Luo, Jie Xiao, Jincan Chen, Hong Xu, Jun Lu, Zhigang Liu, Siping Chen, Mingliang Tong, Kangcheng Zheng and Liangnian Ji

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090226

      Thumbnail image of graphical abstract

      We report an unusual example in which the Λ enantiomer of Ru(II) complex binds to DNA more strongly than its Δ enantiomer, that can be reasonably explained by their different electronic structures calculated by density functional theory based on their crystal structures for the first time, suggesting that DNA binding of chiral molecules can thus be adjusted and controlled by molecular design.

  2. Full Papers

    1. Top of page
    2. Communication
    3. Full Papers
    4. Note
    1. Effect of Combustion Improver on Combustion Behavior of Cigarette Paper by Simultaneous TG/DSC Detection (pages 1322–1326)

      Huirong Li, Yi Liu, Dan Li, Bin Cai, Yikun Chen and Zhangang Cheng

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090227

      Thumbnail image of graphical abstract

      Combustion behavior of cigarette paper containing different content of combustion improver was investigated. The content of the combustion improver was denoted as "organic" potassium index and determined by atomic absorption spectroscopy and ionic spectroscopy. The combustion process obtained by simultaneous thermal analysis were divided into four stages: weight loss due to absorbent water, decomposition of the cellulose, the oxidation of the cellulose char and decomposition of calcium carbonate. Combustion improver reduced the temperature of cellulose decomposition and contributed to oxidation of the cellulose char. Ignition point was gained and reduced 3–8 K by combustion improver. Above results were further verified by samples from two other cigarette paper factories. Mechanism of lower components in cigarette smoke by the combustion improver in cigarette paper was discussed.

    2. A Simple Way for Synthesis of Alkyne-Telechelic Poly(methyl methacrylate) via Single Electron Transfer Radical Coupling Reaction (pages 1327–1330)

      Zhongning Zhang, Qiang Fu and Junlian Huang

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090228

      Thumbnail image of graphical abstract

      The telechelic α,ω-alkyne-poly(methyl methacrylate) (alkyne-PMMA-alkyne) could be easily synthesized by single electron transfer radical coupling reaction of α-alkyne, ω-bromine-poly(methyl methacrylate) (alkyne-PMMA-Br) at 45°C using CuCl/1,1,4,7,10,10-hexamethyl triethylenetetramine (HMTETA) as homogeneous catalytic system.

    3. Structures, IR, NMR Spectra and Thermodynamics Properties of Halogenated Compounds X-1-ZB11H10 (Z[DOUBLE BOND]O, S, Se; X[DOUBLE BOND]F, Cl, Br): A DFT Study (pages 1331–1344)

      Ping Li

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090229

      Thumbnail image of graphical abstract

      The structures and spectra of a series of halogenated twelve-vertex closo-heteroborane have been investigated and predicted theoretically, which are consistent with the experimental data. The chemical thermodynamic properties of the halogenations have been obtained with the significant results. The mechanism of chlorination has been discussed.

    4. A Theoretical Study on the Vibrational Spectra and Thermodynamic Properties for the Derivatives of 2,5-Dipicryl-1,3,4-oxadiazole with N3, ONO2, and NNO2 Groups (pages 1345–1354)

      Guixiang Wang, Xuedong Gong, Yan Liu, Hongchen Du, Xiaojuan Xu and Heming Xiao

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090230

      Thumbnail image of graphical abstract

      The derivatives of 2,5-dipicryl-1,3,4-oxadiazole (DPO) were optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level. Their IR spectra were obtained and assigned by vibrational analysis. Compared with the experimental results, all the calculated IR data were found to be reliable. Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics, the thermodynamic properties were evaluated, which are respectively linearly related with the number of azido, nitrate and nitramine groups as well as the temperature, obviously showing good group additivity.

    5. Density Functional Study of Two Seven-Membered Unconventional Fullerenes C58F17CF3 and C58F18 (pages 1355–1358)

      Chunmei Tang, Weihua Zhu and Kaiming Deng

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090231

      Thumbnail image of graphical abstract

      It is calculated that three sites chosen to locate the CF3 are isoenergetic. The energy gaps of C58F18 and C58F17CF3 are much larger than that of C58, indicating the fluorination and trifluoromethylation of C58 can remarkably enhance the kinetic stability.

    6. Synthesis of Ag/Polypyrrole Core-Shell Nanospheres by a Seeding Method (pages 1359–1362)

      Xiaomiao Feng

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090232

      Thumbnail image of graphical abstract

      Ag/polypyrrole (PPy) core-shell nanospheres were fabricated through the redox reaction between pyrrole monomer and silver nitrate in the presence of polyvinylpyrrolidone (PVP) and by using the Ag colloidal nanoparticles acting as the seedings. The prepared nanospheres with a shell thickness of 10–12 nm and a core diameter of 20–40 nm are uniform in size and well dispersed. The morphologies, compositions, and electrochemical activities of Ag/PPy composites were characterized by TEM, XRD, FTIR, TGA and CV. The synthetic route employed here is gentle and can be extended to prepare other conducting polymer/inorganic nanocomposites.

    7. DFT Study for the Reduction of N2O(1Σ+) with CO(1Σ+) Catalyzed by Cr+ (pages 1363–1368)

      Fengxia Liu, Jianhui Zhang, Minzhe Hu, Yongcheng Wang and Yanli Leng

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090233

      Thumbnail image of graphical abstract

      The mechanism of the reaction N2O(1Σ+)+CO(1Σ+)[RIGHTWARDS ARROW]N2(1Σ+g)+CO2(1Σ+g) catalyzed by Cr+ has been investigated on sextet and quartet potential energy surfaces. The reactions are studied by using the UB3LYP density functional method and the standard 6-311+G(2d) basis sets. The geometries for reactants, the transition states and the products are completely optimized. The result shows that the reaction proceeds in a two-step manner, each mechanism are insertion-elimination and rearrangement mechanism. The involved crossing between the two potential energy surfaces has been discussed by means of the intrinsic reaction coordinate (IRC) approach, and the crossing points (CPs) are located. The minimum energy crossing point (MECP) that we obtained by the mathematical algorithm proposed by Harvey et al. has been also employed. Then the action of frontier molecular orbitals in MECPs was illuminated briefly. Finally, O-atom affinities (OA) testified that the argumentation is thermodynamically allowed.

    8. Evaluating the Thermal Hazard of Double-Base Propellant SQ-2 by Using Microcalorimetry Method (pages 1369–1372)

      Xiaoling Xing, Liang Xue, Fengqi Zhao, Hongxu Gao, Qing Pei and Rongzu Hu

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090234

      Thumbnail image of graphical abstract

      The thermal decomposition behavior of double-base rocket propellant SQ-2 was studied by a Calvet microcalorimeter at four different heating rates. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The critical temperature of thermal explosion (Tb), the self acceleration decomposition temperature (TSADT), the adiabatic decomposition temperature rise (ΔTad), the time-to-explosion of adiabatic system (t), critical temperature of hot-spot initiation (Tcr), critical thermal explosion ambient temperature (Tacr), safety degree (SD) and thermal explosive probability (PTE) were presented to evaluate the thermal hazard of SQ-2.

    9. Syntheses, Crystal Structures and Luminescent Properties of a Dimeric Complex [(bzdmpzm)Cu(µ-I)]2 and a Polymeric Complex [(bzdmpzm)Cu(µ-NCS)]n (bzdmpzm=Bis(4-benzyl-3,5-dimethyl-1H-pyrazol-1-yl)methane) (pages 1373–1378)

      Huihui Wang, Hongxi Li, Zhigang Ren, Yang Chen and Jianping Lang

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090235

      Thumbnail image of graphical abstract

      by pairs of thiocyanates. The luminescence properties of 1 and 2 were also investigated.

    10. Ab initio Study of Mechanism of Forming a Germanic Hetero-Polycyclic Compound between Germylidene (H2C=Ge:) and Acetone (pages 1379–1384)

      Xiuhui Lu, Yuehua Xu, Zhenxia Lian and Yongqing Li

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090236

      Thumbnail image of graphical abstract

      The presented rule of dominant reaction pathways for this reaction: the two reactants (R1, R2) firstly form a four-membered ring intermediate (INT2); the intermediate (INT2) reacts further with acetone (R2) to give another intermediate (INT4); finally, intermediate (INT4) isomerizes to a germanic hetero-polycyclic compound (P4) via a transition state TS4.

    11. Synthesis, Crystal Structure, Luminescence and Thermal Stability of a New Coordination Polymer Constructed by Europium(III) and 2,4-Dichlorophenoxyacetate (pages 1385–1388)

      Yingqun Yang, Changhong Li, Wei Li and Zhengji Yi

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090237

      Thumbnail image of graphical abstract

      A new coordination polymer {[Eu2(Cl2C6H3OCH2COO)6(H2O)4]· (DMF)4·(H2O)2}n with 2,4-dichlorophenoxy acetic acid as the ligand has been synthesized. The complex crystallizes in the monoclinic space group P2(1)/n with the central europium(III) ion ten-coordinated, giving a distorted bicapped square antiprism geometry. The title complex forms one-dimensional chain structure owing to the chelating-bridging tridentate coordination of carboxylic groups. The luminescent property and thermal stability of the complex are also studied.

    12. Synthesis and Photophysics of Novel Soluble Polymeric Zn Metal Complex Based on Bis(8-hydroxyquinoline) Groups with Benzene Unit (pages 1389–1394)

      Yanping Huo and Shizheng Zhu

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090238

      Thumbnail image of graphical abstract

      The phenomenon indicated that the intense interaction of Zn(m-B8QPH) (5) and 11 in excited state had happened.

    13. Electrochemiluminescence Studies of Phosphorescent Dopant and Host Molecules of Polymer Light-emitting Diodes (pages 1395–1399)

      Dongdong Wang, Chaoxin Wu and Xun Hou

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090239

      Thumbnail image of graphical abstract

      In the paper, electrochemiluminescence behaviors from Ir(ppy)3 was investigated following cross reaction of its ions with PVK or PBD. We expect the results obtained will provide further insight into charge-transfer excitation in polymer light-emitting diodes based on phosphorescent Ir(ppy)3 doped blending host of PVK:PBD, and give some direction for future device design.

    14. A Practical Approach to Synthesize the C(9) –C(24) Fragment of (+)-Discodermolide (pages 1400–1408)

      Zengsheng Yin, Xuyi Yue, Xiangjun Deng and Fengling Qing

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090240

      Thumbnail image of graphical abstract

      A practical and stereoselective synthesis of the C(9) –C(24) subunit of (+)-discodermolide has been achieved. The strategy featured the construction of the key intermediate Z-trisubstituted vinyl iodide 12 from the dibromoolefin 6 via an efficient modified Tanino-Miyashita's approach. The union of the two fragments was carried out through a Suzuki cross-coupling reaction.

    15. Synthesis and Reactions of Halo-, Arylazo-substituted 3-(3-(1-naphthyl)acryloyl)tropolones. Formation of (Naphthalen-1-yl)vinyl)substituted Heterocycle-fused Troponoid Compounds (pages 1409–1416)

      Wentao Gao, Mingchun Sun and Yang Li

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090241

      Thumbnail image of graphical abstract

      The starting substrate 3-(3-(1-naphthyl)acryloyl)tropolone (3) was achieved by the aldol condensation reaction of 3-acetyltropolone with 1-naphthaldehyde. Compound 3 reacted with bromine to afford 7-bromo-3-(3-(1-naphthyl)acryl-oyl)tropolone (4), 5,7-dibromo-3-(3-(1-naphthyl)acryloyl)tro-polone (5) according to the molar ratio of the reactants. Iodination of 3 gave 7-iodo-3- (3-(1-naphthyl)acryloyl)tropolone (6). Azo-coupling reactions of 3 gave the 5-arylazo-3-(3-(1-naphthyl)acryloyl)tropolones (78). Compounds 3, 4, 6 reacted respectively with hydroxyamine to give the corresponding 3-[2-(1-naphthyl)vinyl]-8H-cyclohepta[d]isoxazol-8-ones (911). The reactions of 3, 5 with phenylhydrazine and substituted phenylhydrazines gave 3-[2-(1-naphthyl)vinyl]-1-phenylcyclohepta-[c]pyrazol-8(1H)-ones (1218).

    16. Heterodimers of Histidine and Amantadine as Inhibitors for Wild Type and Mutant M2 Channels of Influenza A (pages 1417–1423)

      Wenjuan Zhang, Jing Xu, Fang Liu, Chufang Li, Yanling Jie, Shaopeng Chen, Zhiyuan Li, Jinsong Liu, Ling Chen and Guochun Zhou

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090242

      Thumbnail image of graphical abstract

      Heterodimeric inhibitor 6 containing imidazole and adamantane groups showed good inhibitory activity to WT and mutant M2 channels.

    17. Synthesis of Tridentate Ligands Based on Chiral Diamines and Their Application to Enantioselective Friedel-Crafts Alkylation of Indoles with Nitroalkenes (pages 1424–1428)

      Mei Wu, Shoufeng Wang, Chungu Xia and Wei Sun

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090243

      Thumbnail image of graphical abstract

      A new type of chiral tridentate ligands were prepared and their Zn complexes were examined for the asymmetric Friedel-Craft alkylation of indoles with nitroalkenes, which gave rise to good yields and moderate enantioselectivities.

    18. Synthesis, Characterization and Anti-inflammatory Activity of 5-{[((5-Substituted-aryl)-1,3,4-thiadiazol-2-yl)thio]-n-alkyl}-1,3,4-oxadiazole-2-thiol (pages 1429–1436)

      Pramodkumar Jaykumar Shirote and Manish Sudesh Bhatia

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090244

      Thumbnail image of graphical abstract

      A series of potent and less toxic, 5-{[((5-substituted aryl)-1,3,4-thiadiazol-2-yl)- thio]-n-alkyl}-1,3,4-oxadiazole-2-thiol was synthesized. Each compound was evaluated for anti-inflammatory activity by carrageenan-induced rat paw oedema method. Compounds PS1, PS4, PS9, and PS12 showed comparatively potent anti-inflammatory activity as compared to control as well as other test compounds. These potent compounds were also tested for acute ulcerogenic activity. Results of both studies were found statistically significant.

    19. One-pot Synthesis of 2,4-Diamino-substituted Thieno[3,2-d]pyrimidines (pages 1437–1440)

      Xiaoying Li, Yangming Zhang, Jie Tang, Fan Yang and Fajun Nan

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090245

      Thumbnail image of graphical abstract

      An efficient one-pot synthetic approach to 2,4-diamino-substituted thieno[3,2-d]-pyrimidines from 2,4-dichlorothieno[3,2-d]pyrimidine was described.

    20. Copper-Catalyzed Coupling of Thiourea with Aryl Iodides: The Direct Synthesis of Aryl Thiols (pages 1441–1443)

      Shu Qiao, Kun Xie and Junsheng Qi

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090246

      Thumbnail image of graphical abstract

      A general, economical and efficient protocol for the direct copper-catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large-scale industry as a preferred process.

    21. Equilibrium Studies on Reactive Extraction of α-Cyclohexyl-mandelic Enantiomers Using Hydrophilic β-Cyclodextrin Derivatives Extractants (pages 1444–1450)

      Kewen Tang, Jiabing Miao, Yongbing Liu, Tao Zhou and Litao Song

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090247

      Thumbnail image of graphical abstract

      α-Cyclohexyl-mandelic acid enantiomers were extracted from organic phase to aqueous phase with hydrophilic hydroxypropyl-β-cyclo-dextrin as chiral selector, which has stronger recognition ability for S-enantiomer than for R-enantiomer.

    22. Analysis of the Volatile Components in the Leaves of Cinnamomum camphora by Static Headspace Gas Chromatography Mass Spectrometry Combined with Accurate Weight Measurement (pages 1451–1456)

      Fengjun Zhu and Yinlong Guo

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090248

      Thumbnail image of graphical abstract

      The volatile components in the leaves of C. camphora were analyzed by static headspace-gas chromatography/mass spectrometry (HS-GC-MS) combined with accurate weight measurement. The identification of volatile components was based on comparison of their mass spectra with those of NIST 2002 Library, as well as their retention indices. Furthermore, accurate weight was employed to make sure the identification. It can be seen that this analytical method obtains more reliable identification.

    23. Solid Phase Extraction of Uranium by Naphthalene-Methyltrioctylammonium Chloride and Arsenazo(III) Adsorbent and Subsequent Spectrophotometric Determination (pages 1457–1462)

      M. Behpour, S. M. Ghoreishi, Z. Nikkhah Qamsari, M. Samiei and N. Soltani

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090249

      A simple and effective method has been presented for the preconcentration of uranium by solid phase extraction. For this purpose arsenazo(III) supported on naphthalene-methyltrioctylammonium chloride was used as an adsorbent and uranium solution at pH 3.5 with flow rate of 1 mL·min−1 was passed through the column. Therefore, uranium-arsenazo(III) complex was formed onto column. Uranium was quantitatively eluted with 5 mL of a 0.1% ammonium tetraphenylborate and determined by spectrophotometric method at 652 nm. Several parameters such as pH, amount of reagents, sample volume, etc. were investigated.

    24. Simultaneous Determination of Caffeine and Theophylline in Human Plasma with a Weak Cation Monolithic SPE-column (pages 1463–1468)

      Tao Zhu and Kyung Ho Row

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090250

      Thumbnail image of graphical abstract

      A simple reversed-phase high performance liquid chromatography method was developed to determine the level of caffeine and theophylline in human plasma samples. The sample clean-up step involved the on-line solid-phase extraction of the analytes from plasma samples into a weak cation monolithic column using a column switching system. Separation was performed on a C18 column.

    25. A 4-Methylumbelliferone-based Fluorescent Probe for Sodium New Houttuyfonate (pages 1469–1474)

      Xiaofeng Yang, Liping Wang, Minglei Zhao, Haiping Qi and Yao Wu

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090251

      A new fluorogenic probe for sodium new houttuyfonate (SNH) was proposed. 4-Methylumbelliferyl-2,4-dinitrobenzenesulfonate (4-MUDNBS) was a nonfluorescent compound and was synthesized via the one-step reaction of 4-methylumbelliferone (4-MU) with 2,4-dinitrobenzenesulfonyl chloride. In basic media, SNH was decomposed to produce sodium sulfite, which then reacted with 4-MUDNBS to yield highly fluorescent 4-MU, hence leading to the fluorescence increase of the reaction solution.

    26. You have free access to this content
      A Novel Sample Pretreatment Method for the Analysis of Polybrominated Diphenyl Ethers in Polymers of Waste Electrical and Electronic Equipment (WEEE) (pages 1475–1481)

      Fan Huang, Xiangzhou Meng, Ling Chen, Nan Xiang, Ying Liu and Guangming Li

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090252

      Thumbnail image of graphical abstract

      Influences of polymer sample type [(A) "polymer granule" and (B) "polymer film"] on extraction efficiency of PBDEs from polymers were investigated in this paper.

    27. You have free access to this content
    28. Formation of Hydrophobic Silica Coatings on Stones for Conservation of Historic Sculptures (pages 1487–1490)

      Feigao Xu, Dan Li, Weiling Chen and Shixiang Gao

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090254

      Thumbnail image of graphical abstract

      A hydrophobic silica coating was synthesized to protect historic sculptures from weathering. The stone surface of sample treated with silica coating was covered with a layer of ultrafine spherical silica nanoparticles with a size of about 190 nm. The protective performances resisting acid rain were evaluated.

    29. You have free access to this content
      Novel Conformational Transitions of Human Cytochrome P450 2C8 during Thermal and Acid-induced Unfolding (pages 1491–1502)

      Lu Sun, Zhonghua Wang, Hualin Jiang, Xiangshi Tan and Zhongxian Huang

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090255

      Thumbnail image of graphical abstract

      In this paper, we proved that the thermal and acid-induced P420 2C8 forms are not the same species. We illustrated the schemes for the heme coordination state changes in the unfolding of P450 2C8 in the figure. Fe3+-P450 2C8 could be converted to its Fe2+- P420-CO thermal and acidic forms through three pathways shown in the figures A and B, respectively. In the thermal unfolding process (figure A), the heme was still sited in the cavity of the protein even after the interactions between the heme and its environmental residues were disturbed. In contrast, during the acid-induced unfolding (figure B), heme was released from the active cavity gradually, but it might form a new coordination with an unknown residue on the surface of the protein at a ferrous-CO binding state.

    30. Preparation of Au Nanoparticles on Surface of Two Supports by Adsorption Phase Synthesis (pages 1503–1507)

      Xin Jiang, Ting Wang and Shi Chen

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090256

      Thumbnail image of graphical abstract

      The figure is the TEM pictures of different samples prepared by adding different quantity of NaBH4: 0.0025 g (left), 0.0055 g (middle) and 0.01 g (right). Most of the particles are very small, and mainly distributed on the surface where the color is darker than blank SiO2. Small Au nanoparticles were prone to distribute on the silica surface covered by Ni(OH)2, due to their different surface isoelectric point.

  3. Note

    1. Top of page
    2. Communication
    3. Full Papers
    4. Note
    1. An Efficient and Economical Method for the Preparation of Fmoc-Argω,ω(Boc)2-OH (pages 1508–1509)

      Ruixin Zhu, Ming Xie, Fei Wang, Qi Liu and Tingguo Kang

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/cjoc.201090257

      Thumbnail image of graphical abstract

      The arginine derivative Fmoc-Argω,ω'(Boc)2·OH has been prepared in perfect yield starting from Fmoc-Orn·HCl and N,N′-di-Boc-N′ ′-triflyguanidine with the presence of diisopropylethylamine. This work provides an efficient and economical method for the preparation of this compound.

SEARCH

SEARCH BY CITATION