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Journal articles on the topic 'Borane clusters'

Author: Grafiati

Published: 28 June 2021

Last updated: 6 February 2022

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1

Kiremire, Enos Masheija Rwantale, and Ivan Lule. "Categorization of Boranes Into Clan Series." International Journal of Chemistry 12, no. 1 (April 3, 2020): 107. http://dx.doi.org/10.5539/ijc.v12n1p107.

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Boranes, despite their instability in nature, can be regarded as hydrocarbon relatives since a [BH] fragment corresponds to a carbon [C] skeletal element in terms of the number of valence electrons. The borane formula which can be expressed as BnHm usually appears in such a way that when (n) is even, then (m) is even and when (n) is odd, (m) is odd as well. Through the study of cluster series, it appears that the cluster number K which represents skeletal linkages is usually a whole number. This inherent characteristic confers unique order within borane clusters with nodal connectivity of 5 and the polyhedral nature of the borane clusters. The orderliness of the borane clusters is reflected by the ease of their categorization into clan series and their readily constructed geometrical isomeric structures. The cluster valence electrons can easily be calculated using one of the six recently discovered fundamental equations.

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2

Kiremire, Enos. "Capping and Decapping Series of Boranes." International Journal of Chemistry 7, no. 2 (October 27, 2015): 186. http://dx.doi.org/10.5539/ijc.v7n2p186.

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Whereas many of the capped series of carbonyl clusters of transition metals are known, those of corresponding borane series are unknown. These include the monocapped, bicapped, tricapped, tetracapped and so on. This paper attempts to correlate selected capped series of the carbonyl series with the hypothetical corresponding ones of boranes using 14n and 4n rules. Some selected examples of capped and decapped borane series have been generated and tabulated. The borane clusters are found to follow a precise numerical algorithm. A comparison of selected examples of carbonyl cluster of lower series such as closo, nido and arachno with the corresponding borane clusters has been made. The popularly cited Rudolph system of deducing shapes of clusters is also discussed in terms of decapping series. The use of fragments and their corresponding fragment series enormously simplifies the categorization of molecular formulas into series from which their shapes can be predicted with or without the use of the cluster number (k value). The fragment series vindicates the vital Hoffmann’s isolobal concept very well.

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3

Kiremire, Enos. "Borane Clusters Hiding Inside Carbonyl Clusters." Oriental Journal of Chemistry 31, Special Issue 1(2015) (October 25, 2015): 121–27. http://dx.doi.org/10.13005/ojc/31.special-issue1.15.

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4

Štíbr, Bohumil. "Phosphorus Insertion Into Borane Clusters. A Review." Collection of Czechoslovak Chemical Communications 67, no. 7 (2002): 843–68. http://dx.doi.org/10.1135/cccc20020843.

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A review is presented on the methods of incorporation of phosphorus vertices into borane, carborane and heteroborane clusters. The structural diversity of boron cluster compounds allows for the synthesis of various types of phosphaboranes, phosphacarboranes and phosphaheteroboranes of structurally different cluster shapes, sizes, and positional isomerism. The phosphaborane compounds outlined in this work are direct analogues of corresponding carboranes. This analogy is the main reason for recent interest and developments in this area. A review with 45 references.

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5

Golub, Igor E., Oleg A. Filippov, Vasilisa A. Kulikova, Natalia V. Belkova, Lina M. Epstein, and Elena S. Shubina. "Thermodynamic Hydricity of Small Borane Clusters and Polyhedral closo-Boranes." Molecules 25, no. 12 (June 25, 2020): 2920. http://dx.doi.org/10.3390/molecules25122920.

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Thermodynamic hydricity (HDAMeCN) determined as Gibbs free energy (ΔG°[H]−) of the H− detachment reaction in acetonitrile (MeCN) was assessed for 144 small borane clusters (up to 5 boron atoms), polyhedral closo-boranes dianions [BnHn]2−, and their lithium salts Li2[BnHn] (n = 5–17) by DFT method [M06/6-311++G(d,p)] taking into account non-specific solvent effect (SMD model). Thermodynamic hydricity values of diborane B2H6 (HDAMeCN = 82.1 kcal/mol) and its dianion [B2H6]2− (HDAMeCN = 40.9 kcal/mol for Li2[B2H6]) can be selected as border points for the range of borane clusters’ reactivity. Borane clusters with HDAMeCN below 41 kcal/mol are strong hydride donors capable of reducing CO2 (HDAMeCN = 44 kcal/mol for HCO2−), whereas those with HDAMeCN over 82 kcal/mol, predominately neutral boranes, are weak hydride donors and less prone to hydride transfer than to proton transfer (e.g., B2H6, B4H10, B5H11, etc.). The HDAMeCN values of closo-boranes are found to directly depend on the coordination number of the boron atom from which hydride detachment and stabilization of quasi-borinium cation takes place. In general, the larger the coordination number (CN) of a boron atom, the lower the value of HDAMeCN.

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6

Yan, Jing, Weihong Yang, Qiuyu Zhang, and Yi Yan. "Introducing borane clusters into polymeric frameworks: architecture, synthesis, and applications." Chemical Communications 56, no. 79 (2020): 11720–34. http://dx.doi.org/10.1039/d0cc04709k.

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This feature article summarizes the preparation and applications of borane cluster-containing polymers and covers research progress and future trends of borane cluster-containing linear, dendritic, macrocyclic polymers and metal–organic frameworks.

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7

Štíbr, Bohumil. "Carbon insertion into borane clusters via nucleophilic addition reactions of borane and carborane anions." Journal of Organometallic Chemistry 747 (December 2013): 16–24. http://dx.doi.org/10.1016/j.jorganchem.2013.04.010.

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8

Stibr, Bohumil. "ChemInform Abstract: Carbon Insertion into Borane Clusters via Nucleophilic Addition Reactions of Borane and Carborane Anions." ChemInform 45, no. 5 (January 16, 2014): no. http://dx.doi.org/10.1002/chin.201405225.

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9

Cai-Yun, Zhang, and Wu Hai-Shun. "Structures and Stabilities of Borane and Guest Species Icosahedral Clusters." Acta Physico-Chimica Sinica 20, no. 02 (2004): 118–22. http://dx.doi.org/10.3866/pku.whxb20040202.

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10

Kononova, E. G. "Electronic structure of 10-vertex arachno-borane and -carborane clusters." Computational and Theoretical Chemistry 1026 (December 2013): 17–23. http://dx.doi.org/10.1016/j.comptc.2013.10.007.

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11

Dziedzic, Rafal M., and Alexander M. Spokoyny. "Metal-catalyzed cross-coupling chemistry with polyhedral boranes." Chemical Communications 55, no. 4 (2019): 430–42. http://dx.doi.org/10.1039/c8cc08693a.

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12

Kiremire, Enos Masheija Rwantale. "Carbonyl Chalcogenides Clusters Existing as Disguised Forms of Hydrocarbon Isomers." International Journal of Chemistry 8, no. 3 (June 27, 2016): 35. http://dx.doi.org/10.5539/ijc.v8n3p35.

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<p>The 4n Series Method has been utilized to categorize, analyze and predict structures for transition metal carbonyl, borane, hydrocarbon and Zintl ion clusters. The method is being extended to study carbonyl chalcogenide clusters. Adequate examples have been given to demonstrate the application of the 4n series method to categorize clusters and where possible predict their possible skeletal structures. In this paper, the method is being applied to the study of carbonyl chalcogenide cluster complexes. What has been found is the striking structural similarity of a wide range of carbonyl chalcogenide clusters to those of corresponding hydrocarbon clusters. It was observed that when a derived hydrocarbon from a cluster, F<sub>CH</sub> = C<sub>n</sub>H<sub>q</sub>, is such that n<q, the cluster portrays structural similarity with an equivalent hydrocarbon. On the other hand when n>q, the ‘hydrocarbon character’ becomes reduced and the typical cluster tendencies increase. When n = q, the situation becomes more or less a borderline case. When q=0, then F<sub>CH</sub> = C<sub>n</sub>. When the series becomes bi-capped or more, then the equivalent carbon cations are obtained.</p>

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13

Echeverri, Andrea, Tatiana Gomez, and C. Z. Hadad. "Ammonia borane dehydrogenation tendencies using Pt4, Au4, and Pt2Au2 clusters as catalysts." Molecular Catalysis 471 (July 2019): 9–20. http://dx.doi.org/10.1016/j.mcat.2019.04.012.

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14

Patwari, G. Naresh, Takayuki Ebata, and Naohiko Mikami. "Gas phase dihydrogen bonding: clusters of borane-amines with phenol and aniline." Chemical Physics 283, no. 1-2 (October 2002): 193–207. http://dx.doi.org/10.1016/s0301-0104(02)00529-3.

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15

Barton, Lawrence, Oleg Volkov, Mitsuhiro Hata, Paul McQuade, and Nigam P. Rath. "Reactions of boranes and metallaboranes with phosphines." Pure and Applied Chemistry 75, no. 9 (January 1, 2003): 1165–73. http://dx.doi.org/10.1351/pac200375091165.

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This paper reports extensions of the well-established field of phosphine–borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2 [(Fe(C5H4)2]}, are formed in reactions of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9]. Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10] and [9,9-(PPh3)2-nido-9,7,8-RhC2B8 H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(µ-dppm)]-closo -1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron vertices in the cage, [1,1-(ç2-dppe)-3-(ç1-dppm)-closo-1,2-RhSB 9H8], a mixed ligand system, and {9,9-ç2-[(ç2-BH3)PPh2PCH2 PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described as is an example of a bidentate phosphine-polyhedral borane adduct [NR4][B11H12(dppm)] in which the borane cage is isoelectronic with [B11H14]–. Finally, a novel oxidative coupling reaction promoted by Cp2ZrCl2/n-BuLi to form the new nonaborane cage system, arachno -B9H11(PPh3)2, an unusual homolog of the well-known species B10H12(PPh3)2, is reported.

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16

Hop, Cornelis E. C. A., Dovas A. Saulys, and Donald F. Gaines. "Electrospray Mass Spectrometry of Borane Salts: Observation of High Molecular Weight Ion Clusters." Inorganic Chemistry 34, no. 8 (April 1995): 1977–78. http://dx.doi.org/10.1021/ic00112a003.

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17

Vijayalakshmi, Kunduchi P., and Cherumuttathu H. Suresh. "Ammonia Borane Clusters: Energetics of Dihydrogen Bonding, Cooperativity, and the Role of Electrostatics." Journal of Physical Chemistry A 121, no. 13 (March 24, 2017): 2704–14. http://dx.doi.org/10.1021/acs.jpca.7b01527.

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18

Mebel, Alexander M., Keiji Morokuma, and Djamaladdin G. Musaev. "Ab Initio MO Study of Cluster Rearrangements in Pentagonal Pyramidal Clusters: B6H10 Borane and [(IrB5H8)(CO)(PH3)2] Metallaborane." Journal of the American Chemical Society 116, no. 9 (May 1994): 3932–42. http://dx.doi.org/10.1021/ja00088a032.

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19

Lee, Stephen. "Nido-n (n = 8, 10, 12) borane and carborane clusters and second moment scaling." Inorganic Chemistry 31, no. 14 (July 1992): 3063–66. http://dx.doi.org/10.1021/ic00040a015.

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20

Gillespie, Ronald J., William W. Porterfield, and Kenneth Wade. "A “vertex electron pair” scheme (VEPS) for describing the skeletal electron distribution in borane-type clusters." Polyhedron 6, no. 12 (January 1987): 2129–35. http://dx.doi.org/10.1016/s0277-5387(00)84275-8.

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21

King, R. B., I. Silaghi-Dumitrescu, and A. Lupan. "Density Functional Study of 8- and 11-Vertex Polyhedral Borane Structures: Comparison with Bare Germanium Clusters." Inorganic Chemistry 44, no. 22 (October 2005): 7819–24. http://dx.doi.org/10.1021/ic050656z.

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22

Viñas, Clara, Rosario Núñez, Ines Bennour, and Francesc Teixidor. "Periphery Decorated and Core Initiated Neutral and Polyanionic Borane Large Molecules: Forthcoming and Promising Properties for Medicinal Applications." Current Medicinal Chemistry 26, no. 26 (October 22, 2019): 5036–76. http://dx.doi.org/10.2174/0929867326666190603123838.

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A mini-review based on radial growing macromolecules and core initiated Borane periphery decorated with o-carboranes and metallacarboranes that has been developed in the authors laboratories is reported. The review is divided into four sections; three of them are related to the design and synthesis of these large boron-containing molecules and the fourth deals with the unique properties of anionic metallacarborane molecules that provide a glimpse of their potential for their promising use in medicinal applications. Their unique stability along with their geometrical and electronic properties, as well as the precise steric structure of 1,2-closo-C2B10H12 (o-carborane) that has the potential for the incorporation of many substituents: at the carbon (Cc), at the boron and at both carbon and boron vertices, suggests this cluster as an innovative building block or platform for novel applications that cannot be achieved with organic hydrocarbon compounds. Poly(aryl-ether) dendrimers grown from fluorescent cores, such as 1,3,5-triarylbenzene or meso-porphyrins, have been decorated with boron clusters to attain rich boron containing dendrimers. Octasilsesquioxane cubes have been used as a core for its radial growth to get boron-rich large molecules. The unique properties of cobaltabisdicarbollide cluster, which include: i) self-assembly in water to produce monolayer nano-vesicles, ii) crossing lipid bilayer membranes, iii) interacting with membrane cells, iv) facilitating its visualization within cells by Raman and fluorescence techniques and v) their use as molecular platform for “in vivo” imaging are discussed in detail.

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23

Chandra, Manish, and Qiang Xu. "Room temperature hydrogen generation from aqueous ammonia-borane using noble metal nano-clusters as highly active catalysts." Journal of Power Sources 168, no. 1 (May 2007): 135–42. http://dx.doi.org/10.1016/j.jpowsour.2007.03.015.

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24

Ge, Yuzhen, Wanyue Ye, Zameer Hussain Shah, Xijie Lin, Rongwen Lu, and Shufen Zhang. "PtNi/NiO Clusters Coated by Hollow Sillica: Novel Design for Highly Efficient Hydrogen Production from Ammonia–Borane." ACS Applied Materials & Interfaces 9, no. 4 (January 20, 2017): 3749–56. http://dx.doi.org/10.1021/acsami.6b15020.

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25

King, R. B. "Flattening of Rhodium Vertices in Mixed Rhodium−Nickel Carbonyl Clusters: Relationships to Borane and Zintl Ion Structures." Inorganic Chemistry 41, no. 18 (September 2002): 4722–26. http://dx.doi.org/10.1021/ic0202662.

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26

Grüner, Bohumír, Tomáš Jelínek, Zbyněk Plzák, John D. Kennedy, Daniel L. Ormsby, Robert Greatrex, and Bohumil Štíbr. "The Parent Hexacarbaboranearachno-C6B6H12 and a Methylated Pentacarbaboranearachno-CH3C5B7H12: Domains of Incipient Hydrocarbon Behavior within Borane Clusters." Angewandte Chemie International Edition 38, no. 12 (June 14, 1999): 1806–8. http://dx.doi.org/10.1002/(sici)1521-3773(19990614)38:12<1806::aid-anie1806>3.0.co;2-o.

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27

Littger, Ralf, Jesse Taylor, George Rudd, Amy Newlon, Damian Allis, Sandy Kotiah, and James T. Spencer. "ChemInform Abstract: Thermal, Photochemical, and Redox Reactions of Borane and Metallaborane Clusters with Applications to Molecular Electronics." ChemInform 31, no. 48 (November 28, 2000): no. http://dx.doi.org/10.1002/chin.200048261.

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28

Gribanova, T. N., R. M. Minyaev, and V. I. Minkin. "Stabilization of Planar Four-Coordinate Boron, Carbon, and Silicon Atoms in Borane Clusters: A Quantum-Chemical Study." Russian Journal of General Chemistry 75, no. 10 (October 2005): 1651–58. http://dx.doi.org/10.1007/s11176-005-0482-9.

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29

Einholz, Wolfgang, Ronald Schäfer, Willi Keller, and Bernhard Vogler. "Zwölfgliedrige Heteroborancluster durch Copyrolyse von Tetrachlordiboran(4) mit Elementhalogeniden/ Twelve-Vertex Heteroborane Clusters by Copyrolysis of Tetrachlorodiborane(4) and Element Halides." Zeitschrift für Naturforschung B 52, no. 2 (February 1, 1997): 221–26. http://dx.doi.org/10.1515/znb-1997-0214.

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Abstract The perchlorinated arsaboranes closo-1,2-As2B10Cl10 and As4B8C16 are formed in the co pyrolysis of B2C14 and AsCl3 at temperatures of 330-450°C. The icosahedral structure of closo-1,2-As2B10Cl10 is confirmed by 11B-11B-COSY-NMR spectroscopy. As4B8Cl6 is suppo sed to be a conjuncto-borane (As2B4Cl3)2 with two boron-boron linked As2B4Cl3 octahedra. The copyrolysis of B2Cl4 andSbCl3 or SbCl5 yields Sb2B10Cl10, and the corresponding reaction of B2Cl4 with S2Cl2 gives the icosahedral thiaborane cluster SB11Cl11 .

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30

Hollfelder, Christoph O., Melanie Meermann-Zimmermann, Georgios Spiridopoulos, Daniel Werner, Karl W. Törnroos, Cäcilia Maichle-Mössmer, and Reiner Anwander. "C–H-Bond Activation and Isoprene Polymerization Studies Applying Pentamethylcyclopentadienyl-Supported Rare-Earth-Metal Bis(Tetramethylaluminate) and Dimethyl Complexes." Molecules 24, no. 20 (October 15, 2019): 3703. http://dx.doi.org/10.3390/molecules24203703.

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As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (C5Me5 = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe2]3 are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe4)2] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C–H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)5(CH2)(Me)8] and metallocene dimers [Cp*2Ln(AlMe4)]2 (Ln = Tb, Gd). Applying TBME as a “cleaving” reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)2(Me)(CH2OtBu)2(AlMe4)]4 or monolanthanum complex [Cp*La(AlMe4){Me3Al(CH2)OtBu}] and monoyttrium complex [Cp*Y(AlMe4)(Me3AlOtBu)], respectively. Complexes [Cp*Ln(AlMe4)2] (Ln = Ho, Dy, Tb, Gd) and [Cp*LnMe2]3 (Ln = Ho, Dy) are applied in isoprene and 1,3-butadiene polymerization, upon activation with borates [Ph3C][B(C6F5)4] and [PhNHMe2][B(C6F5)4], as well as borane B(C6F5)3. The trans-directing effect of AlMe3 in the binary systems [Cp*Ln(AlMe4)2]/borate is revealed and further corroborated by the fabrication of high-cis-1,4 polybutadiene (97%) with “aluminum-free” [Cp*DyMe2]3/[Ph3C][B(C6F5)4]. The formation of multimetallic active species is supported by the polymerization activity of pre-isolated cluster [(Cp*Ho)3Me4(CH2)(thf)2].

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31

Liao, Rongbao, Lanlan Chai, and Yun Zhu. "A theoretical study on the stability difference of the borane BnHn2− and carborane C2Bn−2Hn(5 ≤ n ≤ 7) clusters." International Journal of Quantum Chemistry 115, no. 4 (November 28, 2014): 216–23. http://dx.doi.org/10.1002/qua.24834.

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32

Basil, John D., Allen A. Aradi, Nripendra K. Bhattacharyya, Nigam P. Rath, Charles Eigenbrot, and Thomas P. Fehlner. "Synthesis and reactivity of the metal-substituted borane (CO)4CoBH2.cntdot.THF. Preparation of the ambiphilic clusters (CO)9Co3C(CH2)nOH (n = 4,5)." Inorganic Chemistry 29, no. 6 (March 1990): 1260–70. http://dx.doi.org/10.1021/ic00331a029.

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33

Lepšík, Martin, Martin Srnec, Drahomír Hnyk, Bohumír Grüner, Jaromír Plešek, Zdeněk Havlas, and Lubomír Rulíšek. "exo-Substituent effects in halogenated icosahedral (B12H122–) and octahedral (B6H62–) closo-borane skeletons: chemical reactivity studied by experimental and quantum chemical methods." Collection of Czechoslovak Chemical Communications 74, no. 1 (2009): 1–27. http://dx.doi.org/10.1135/cccc2008189.

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The exo-substituent effects in halogenated icosahedral B12H122– (B12) and octahedral B6H62– (B6) closo-borane skeletons were studied both experimentally and theoretically. Firstly, the equilibrium geometries of exo-substituted B12 and B6 clusters were obtained using quantum chemical calculations at the MP2/def2-SVP level. A comparison with the available X-ray crystallographic data revealed a very good agreement between the theoretical and experimental values. Secondly, other descriptors of the molecular structure of these borane compounds – 11B NMR chemical shifts – were experimentally determined and compared with the calculated values obtained by the ab initio/GIAO approach at the MP2/def2-TZVP level. It was shown that the calculated data reproduced the experiment very closely. Thirdly, we investigated experimentally the halogenation reactions of B12 and attempted to explain the observed ratios between the two obtained disubstituted products (meta/ortho ~ 4:1) by calculating their thermodynamic stabilities using the DFT/B3LYP method. These calculations showed the enhanced stability of the meta disubstituted B12 but did not explain why the para product had not been observed in the experiment. We thus turned our attention to the kinetic aspects of exo-substitution reactions by exploring the possible reaction pathways and transition states. In spite of the complexity of the plausible reaction mechanisms, reasonable agreement was obtained between the calculated activation barriers and the experimental observations concerning the halogenation reactions of the B6 and B12 molecules. It also allowed to exclude from considerations certain reaction pathways leading to the mono- and dihalogenated B12 and B6 species.

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34

Bould, Jonathan, Anna Laromaine, Neil J. Bullen, Clara Viñas, Mark Thornton-Pett, Reijo Sillanpää, Raikko Kivekäs, John D. Kennedy, and Francesc Teixidor. "Borane reaction chemistry. Alkyne insertion reactions into boron-containing clusters. Products from the thermolysis of [6,9-(2-HCC–C5H4N)2-arachno-B10H12]." Dalton Transactions, no. 12 (2008): 1552. http://dx.doi.org/10.1039/b715845a.

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35

Macháček, Jan, Antonio Francés-Monerris, Naiwrit Karmodak, Daniel Roca-Sanjuán, Jindřich Fanfrlík, Michael G. S. Londesborough, Drahommír Hnyk, and Eluvathingal D. Jemmis. "A theoretical analysis of the structure and properties of B26H30 isomers. Consequences to the laser and semiconductor doping capabilities of large borane clusters." Physical Chemistry Chemical Physics 21, no. 24 (2019): 12916–23. http://dx.doi.org/10.1039/c9cp02371b.

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36

Tarter, Michael E., and Stefano Poni. "A Vitis vinifera Cluster's Wing-related Structural Characteristics and Their Associations with Yield and Berry Composition." HortScience 45, no. 8 (August 2010): 1270–77. http://dx.doi.org/10.21273/hortsci.45.8.1270.

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The hypotheses considered in this article concern the basic question, besides bearing a wing, in what ways do wing-bearing and non-wing-bearing clusters differ? Vines sampled at midseason were again selected at harvest. Each weight of a Vitis vinifera cluster sampled at midseason was multiplied by the number of clusters on the vine from which the cluster had been selected. Correlation coefficients between this quantity and the sampled vine's yield at harvest differed significantly in the sense that coefficients determined solely from the subset of sampled clusters on which a wing (a lateral arm originating from the peduncle and separate from the main body of the cluster) was present were found to be larger than coefficients determined from all sampled clusters. To shed light on distinguishing characteristics of clusters that bore wings, the weights of clusters that had been sampled at midseason were studied. Despite being weighed after the removal of their wings, clusters that had wings were found to be significantly heavier than clusters (sampled at the same midseason date) that had never had wings. Box and whisker plots were constructed to assess this finding as well to study the relationships between a Vitis vinifera rachis' (a cluster's principal axis) weight, length, and diameter and wing absence or presence. For each of the five vineyard blocks that we studied, the median rachis midseason diameters of wing-bearing clusters exceeded the median rachis diameters of non-wing-bearing clusters. Concerning ‘Cabernet Sauvignon’ Vitis vinifera clusters that had wings, it was also found that the late-season differences between the median soluble solids concentrations (°Brix) of wing-borne berries and the median °Brix of non-wing-borne berries were inappreciable.

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37

Kuno, Goro, Gwong-Jen J. Chang, K. Richard Tsuchiya, Nick Karabatsos, and C. Bruce Cropp. "Phylogeny of the Genus Flavivirus." Journal of Virology 72, no. 1 (January 1, 1998): 73–83. http://dx.doi.org/10.1128/jvi.72.1.73-83.1998.

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ABSTRACT We undertook a comprehensive phylogenetic study to establish the genetic relationship among the viruses of the genusFlavivirus and to compare the classification based on molecular phylogeny with the existing serologic method. By using a combination of quantitative definitions (bootstrap support level and the pairwise nucleotide sequence identity), the viruses could be classified into clusters, clades, and species. Our phylogenetic study revealed for the first time that from the putative ancestor two branches, non-vector and vector-borne virus clusters, evolved and from the latter cluster emerged tick-borne and mosquito-borne virus clusters. Provided that the theory of arthropod association being an acquired trait was correct, pairwise nucleotide sequence identity among these three clusters provided supporting data for a possibility that the non-vector cluster evolved first, followed by the separation of tick-borne and mosquito-borne virus clusters in that order. Clades established in our study correlated significantly with existing antigenic complexes. We also resolved many of the past taxonomic problems by establishing phylogenetic relationships of the antigenically unclassified viruses with the well-established viruses and by identifying synonymous viruses.

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38

Taylor, Jesse W., Ulrich Englich, Karin Ruhlandt-Senge, and James T. Spencer. "Formation of new nickel-containing nineteen-vertex metallaborane clusters prepared from the anti-B18H22 borane cluster: molecular structures of [Ni(THF)4(H2O)2][B18H20Ni(η5-C5H5)]2 and [B18H19(2-THF)Ni(η5-C5H5)]." Journal of the Chemical Society, Dalton Transactions, no. 17 (2002): 3392. http://dx.doi.org/10.1039/b203594d.

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Charkin, Oleg P., Nina M. Klimenko, Damian Moran, Alexander M. Mebel, Dmitry O. Charkin, and Paul v. R. Schleyer. "Theoretical Study of Complexes of Closo-Borane, Alane, and Gallane Anions with Cations of Light Metals Inside and Outside of Icosahedral Clusters [A12H122-] (A = B, Al, and Ga)." Journal of Physical Chemistry A 106, no. 47 (November 2002): 11594–602. http://dx.doi.org/10.1021/jp021407o.

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Brint, Paul, Benchang Sangchakr, Patrick W. Fowler, and Vincent J. Weldon. "Bonding in clusters. Part 10. The nature of the BH groups in closo-borane anions. A study by vibrational spectroscopy, electronic spectroscopy for chemical analysis, and ab initio computation." Journal of the Chemical Society, Dalton Transactions, no. 11 (1989): 2253. http://dx.doi.org/10.1039/dt9890002253.

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Cousins*, Peter. "Correlation of Basal Node and Cluster Numbers in Grapevines." HortScience 39, no. 4 (July 2004): 804D—804. http://dx.doi.org/10.21273/hortsci.39.4.804d.

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The grapevine shoot consists of nodes without clusters (inflorescences) basal to a zone in which leaf-opposed clusters are found at the nodes. Beyond the cluster zone leaf-opposed tendrils are borne at the nodes. The numbers and possible relationship of basal nodes and clusters are important in grapevine breeding and improvement. Basal node number influences cluster placement within the canopy, which relates to light penetration to the fruit and fruit maturation and to application of cultural practices, including harvest and cluster treatments. Cluster number is a primary yield component. Basal node and clusters numbers were counted on ten primary shoots each of forty grapevine (Vitis) accessions. The accessions analyzed are cultivars and wild species collections held in the United States National Plant Germplasm System. The correlation coefficient of the number of basal nodes and number of clusters was calculated using the means of the ten observations per accession. Basal node and clusters numbers were negatively correlated; the correlation coefficient was -0.763, which is significant (P <0.001). The negative correlation of basal node and cluster number has implications for grapevine improvement.

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Shore, S. G. "Borane-osmium cluster chemistry." Pure and Applied Chemistry 66, no. 2 (January 1, 1994): 263–72. http://dx.doi.org/10.1351/pac199466020263.

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Kiremire, Enos Masheija Rwantale. "Graph Theory of Capping Golden Clusters." International Journal of Chemistry 10, no. 1 (January 25, 2017): 87. http://dx.doi.org/10.5539/ijc.v10n1p87.

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Skeletal numbers and their valences have been extremely useful in analyzing and categorizing clusters especially boranes, carbonyls, and Zintl ions. This approach is being extended to the analysis and categorization of golden clusters. The newly introduced concept of graphing will also be applied to the clusters. The capping symbol Kp = CYC[Mx] which has been restricted to post-closo clusters will be adapted for pre-closo cluster series. The concept of the existence of black holes in the nuclei of capping golden clusters will be introduced and explained.

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Eliezer, S., and J. M. Martínez-Val. "Proton–boron-11 fusion reactions induced by heat-detonation burning waves." Laser and Particle Beams 16, no. 4 (December 1998): 581–98. http://dx.doi.org/10.1017/s0263034600011411.

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Proton-boron-11 is the clean fusion reactionpar excellence, but it is very difficult to exploit it because of the very high ignition temperature of this reaction and its moderate fusion yield. In this paper, a proposal is made to induce these reactions by a heat-detonation wave that expands across a compressed target. The front of the wave has a double-layer structure, with a first front driven by electron heat conduction and a second front heated by α-particle energy deposition. Both fronts create a hot plasma where the stopping power is dominated by ions. The wave is originated by an ignitor triggered by an ultraintense lightning beam. This beam can be made of photons (laser), plasma (ramjets), or ions (proton beams, borane clusters). Proton beam shots of 1022. W/cm2and several GA for some picoseconds would be needed for this purpose. The supersonic propagation of the fusion wave and the ignitor requirements are analyzed in this paper. The main conclusion is that the burning wave can only propagate if a substantial fraction of the radiation losses from the already burning fuel is reabsorbed in the colder fuel. It is calculated that for densities larger than few thousands g/cm3most of the bremsstrahlung radiation created in the hot plasma can be reabsorbed by the Compton effect in a region of 1 g/cm2optical thickness of the surrounding compressed and cold fuel.

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Hauser, Elisabeth, Alexander Mellmann, Torsten Semmler, Helen Stoeber, Lothar H. Wieler, Helge Karch, Nikole Kuebler, et al. "Phylogenetic and Molecular Analysis of Food-Borne Shiga Toxin-Producing Escherichia coli." Applied and Environmental Microbiology 79, no. 8 (February 15, 2013): 2731–40. http://dx.doi.org/10.1128/aem.03552-12.

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ABSTRACTSeventy-five food-associated Shiga toxin-producingEscherichia coli(STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI ICL3, and the autotransporter-encoding genesabAwas examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE),selC,pheU, andpheV, as well as the Stx phage integration sitesyehV,yecE,wrbA,z2577, andssrA, was analyzed. Moreover, the antibiotic resistance phenotypes of all STEC strains were determined. Multilocus sequence typing (MLST) was performed, and sequence types (STs) and sequence type complexes (STCs) were compared with those of 42 hemolytic-uremic syndrome (HUS)-associated enterohemorrhagicE. coli(HUSEC) strains. Besides 59 STs and 4 STCs, three larger clusters were defined in this strain collection. Clusters A and C consist mostly of highly pathogeniceae-positive HUSEC strains and some related food-borne STEC strains. A member of a new O26 HUS-associated clone and the 2011 outbreak strainE. coliO104:H4 were found in cluster A. Cluster B comprises onlyeae-negative food-borne STEC strains as well as mainlyeae-negative HUSEC strains. Although food-borne strains of cluster B were not clearly associated with disease, serotypes of important pathogens, such as O91:H21 and O113:H21, were in this cluster and closely related to the food-borne strains. Clonal analysis demonstrated eight closely related genetic groups of food-borne STEC and HUSEC strains that shared the same ST and were similar in their virulence gene composition. These groups should be considered with respect to their potential for human infection.

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Jones, Robert T., Elizabeth Pretorius, Thomas H. Ant, John Bradley, Anna Last, and James G. Logan. "The use of islands and cluster-randomized trials to investigate vector control interventions: a case study on the Bijagós archipelago, Guinea-Bissau." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1818 (December 28, 2020): 20190807. http://dx.doi.org/10.1098/rstb.2019.0807.

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Vector-borne diseases threaten the health of populations around the world. While key interventions continue to provide protection from vectors, there remains a need to develop and test new vector control tools. Cluster-randomized trials, in which the intervention or control is randomly allocated to clusters, are commonly selected for such evaluations, but their design must carefully consider cluster size and cluster separation, as well as the movement of people and vectors, to ensure sufficient statistical power and avoid contamination of results. Island settings present an opportunity to conduct these studies. Here, we explore the benefits and challenges of conducting intervention studies on islands and introduce the Bijagós archipelago of Guinea-Bissau as a potential study site for interventions intended to control vector-borne diseases. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases'.

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Zhang, Zhen, Hannamari Hintsa, Ying Chen, Hannu Korkeala, and Miia Lindström. "Plasmid-Borne Type E Neurotoxin Gene Clusters in Clostridium botulinum Strains." Applied and Environmental Microbiology 79, no. 12 (April 5, 2013): 3856–59. http://dx.doi.org/10.1128/aem.00080-13.

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ABSTRACTA collection of 36Clostridium botulinumtype E strains was examined by pulsed-field gel electrophoresis (PFGE) and Southern hybridization with probes targeted tobotEandorfX1in the neurotoxin gene cluster. Three strains were found to contain neurotoxin subtype E1 gene clusters in large plasmids of about 146 kb in size.

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Cousins, Peter. "(231) Correlation of Cluster Number and Tendril Density in Grapevines." HortScience 40, no. 4 (July 2005): 1008C—1008. http://dx.doi.org/10.21273/hortsci.40.4.1008c.

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The grapevine shoot has a zone in which leaf-opposed clusters are found at the nodes. Beyond the cluster zone, leaf-opposed tendrils are borne at the nodes in a patterned distribution. Cluster number is a primary yield component and selection programs for increasing yield in grapevine frequently consider cluster number. However, selection for increased cluster number requires direct observation, which is only possible once the vine matures. Clusters and tendrils are developmentally related, so it may be that tendril density (tendrils per node) reflects cluster number. In contrast to cluster number, tendril density can be observed on plants of all ages. The hypothesis that tendril density is related to cluster number was tested here. Cluster numbers and tendril density were assessed on 10 primary shoots each of 180 grapevine (Vitis) accessions. The accessions analyzed are cultivars and wild species collections held in the United States National Plant Germplasm System. The correlation coefficient of the number of clusters and tendril density was calculated using the means of 10 observations per accession. Tendril density was determined by calculating the mean number of tendrils per node in the nodes beyond the cluster zone. Cluster number and tendril density were positively correlated; the correlation coefficient was 0.35. This implies that vines with more tendrils per node also tend to have more clusters. The positive correlation of cluster number and tendril density has implications for grapevine improvement, pointing to the possibility of indirect selection for higher cluster number through selection for higher tendril density. Correlation between juvenile tendril density and mature cluster number is yet to be tested.

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Goodman, Joseph H., John M. McGregor, Nancy R. Clendenon, Reinhard A. Gahbauer, Ralph G. Fairchild, Rolf F. Barth, and A. H. Soloway. "Ultrastructural Microvascular Response to Boron Neutron Capture Therapy in an Experimental Model." Neurosurgery 24, no. 5 (May 1, 1989): 701–8. http://dx.doi.org/10.1227/00006123-198905000-00007.

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ABSTRACT A CD 344 rat glioma model currently used to investigate boron neutron capture therapy (BNCT) was used to demonstrate an increased survival rate after thermal neutron irradiation enhanced by administration of 10B-enriched polyhedral borane, Na2B12H11SH. To investigate the possible effects of BNCT on normal and tumor microvasculature, we subjected animals to sublethal neutron irradiation with and without intravenous injection of 50 mg/kg of enriched 10B and performed histological and ultrastructural analyses. In the rats that did not undergo tumor transplantation, minimal detectable morphological changes in the microvasculature of the central nervous system were observed after treatment, both in the immediate posttreatment phase and at 10 months. Light microscopy of cerebral cortex and caudate nucleus showed normal cytoarchitecture with no evidence of vessel occlusion, hyalinization, thickening, or reactive gliosis. Electron microscopy demonstrated that the junctional complexes of the endothelial cells, the basal lamina, and the perivascular glia were comparable in both treated and control animals. In those animals examined at 18 months, pathological membrane-bound clusters of electron-dense vesicles were seen in pericytes. In the rats implanted with gliomas, vascular proliferation with evidence of breakdown of the blood-brain barrier and vasogenic edema occurred. In the irradiated animals, we noted increased peritumoral edema 3 days after treatment. At seven days, both increased peritumoral edema and necrosis were noted in the rats treated with BNCT. These observations show that the normal microvasculature of the central nervous system tolerates BNCT at the treatment parameters used in our experimental model; the progressive edema and necrosis found in the peritumoral region after BNCT indicate a pathological endothelial response.

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Leonova, G. N., L. M. Somova, and S. I. Belikov. "Molecular-genetic characteristics of the tick-borne encephalitis virus pathogenicity of far eastern subtype." Journal Infectology 12, no. 1 (March 21, 2020): 48–55. http://dx.doi.org/10.22625/2072-6732-2020-12-1-48-55.

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The aim of the work: Using the data of genome-wide sequencing of tick-borne encephalitis virus strains of the Far Eastern population, reveal the peculiarities of the moleculargenetic characteristics and their relationship with the pathogenicity of the agent. Materials and methods. A full-genomic characteristic of 63 TBEV strains isolated in the Far East and registered in GeneBank wos given. A pathohistological study of the central nervous system of monkeys infected with the highly virulent strains Sofjin and Khabarovsk-17 TBEV was conducted. Results. All strains are assigned to the Far Eastern subtype of TBEV and are located in three clusters, the territorial attachment of individual strains groups is noted. In the cluster of Sofjin-like strains, independent groups were identified, isolated in the territories of Primorsky Krai only, and separate groups – only in northern focal territories (Khabarovsk Krai). The cluster Senzhang-like strains are represented by strains of different clusters, isolated in China and throughout the Far East. The Oshima-like cluster of strains, except for strains from Japan, consists of strains isolated only in the south of the Far East (in Primorsky Krai). The incubation period of the disease in experimental animals was shorter when infected with the Sofjin strain (3–5 days) than when infected with the Khabarovsk-17 strain (7 days or more). The strain-specific differences in the severity of morphological changes in the central nervous system were revealed. For primorsky TBEV strains, a higher degree of neuroinvasiveness was characteristed with a more rapid development of severe manifestations of neuroinfection, compared to khabarovsky strains.Findings: 1) based on full-genome sequencing and phylogenetic analysis of 63 TBEV strains, three main clusters were distinguished: Sofjin-, Senzhang- and Oshima-like; 2) in these clusters, territorial attachment of TBEV strains groups with a certain molecular genetic characteristic was established; 3) in primorsky TBEV strains, genetically determined advantages in the degree of neuroinvasiveness have been revealed, which provide them with the ability to more quickly overcome the blood-brain barrier compared to khabarovsky strains.

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