Dumbbell structures

N. Dragoe, S. Tanibayashi, K. Nakahara, S. Nakao, H. Shi-motani, L. Xiao, K. Kitazawa, Y. Achiba, K. Kikuchi, K. Nojima, Carbon Allotropes of Dumbbell Structure Cm and Cm , Chem. Commun. 1999, 85-86. 

Figure 4. Influence of three-fold astigmatism, A3, on HRTEM images of diamond in [110] orientation (left A3 = 2250 nm right A3 < 50 nm). When the 3-fold astigmatism is corrected, the HRTEM image shows the dumbbell-structure of diamond, whereas strong 3-fold astigmatism results in an image that cannot be directly interpreted in terms of the atomic...

The x-ray structure of free calmodulin was determined by the group of Charles Bugg, University of Alabama. It is a dumbbell-shaped molecule... 

An atom consists of a positively charged nucleus surrounded by one or more negatively charged electrons. The electronic structure of an atom can be described by a quantum mechanical wave equation, in which electrons are considered to occupy orbitals around the nucleus. Different orbitals have different energy levels and different shapes. For example, s orbitals are spherical and p orbitals are dumbbell-shaped. The ground-state electron configuration of an... 

Actin is a 42 kDa bent dumbbell-shaped globular monomer which is found in most eukaryotic cells. It is the primary protein of the thin (or actin) filaments. Also, by mass or molarity, actin is the largest constituent of the contractile apparatus, actually reaching millimolar concentrations. Actins from different sources seem to be more similar than myosins from the same sources. Actin binds ATP which is hydrolyzed to ADP, if the monomeric actin polymerizes. The backbone structure of the actin filament is a helix formed by two linear strands of polymerized actins like two strings of actin beads entwined. 

The superstructure of smooth muscle actin filaments is differentiated from those of striated muscle by the absence of the troponins and the lateral organization by association of the filaments with dense bodies instead of with the Z-line. How these differences are encoded is again not at all clear. However, the myofibrillar structure and the alignment of the alternating actin and myosin filaments is apparently due primarily to dense bodies and the actin-actinin macrostructures. As the bent dumbbell shaped actins assemble into filaments they are all oriented in the same direction. The S-1 fragments of myosin will bind to actin filaments in vitro and in... 

In Li2Sb we can assume Sb2- particles with seven valence electrons. Therefore, we expect Sb2 dumbbells (isoelectronic with I2) and observance of the octet rule. In fact, such dumbbells are present in the structure (Sb-Sb bond length 297 pm) however, this applies only to half of the Sb atoms. The other half form linear chains of Sb atoms (Sb-Sb distance 326 pm). For the bonds in the chain we assume a band according to Fig. 10.5 (p. 93) every Sb atom contributes to this band with one p orbital and one electron. With one electron per Sb atom the band is half-occupied, and therefore it is bonding. The... 

Hie chromatinic structures in E. coli from old cultures were too small to be resolved accurately. After transfer to fresh medium the chromatinic structures increased in size and gave rise to short, often dumbbell-shaped rods or chromosomes, which multiplied by splitting lengthwise in a plane more or less parallel to the short axis of the cell. A single cell of E. coli contained one chromatinic body or one or two pairs of these representing primary and secondary division products. 

Besides the oxide sulfate described above, (NH4)2[Pt2(S04)4(H20)2] is obtained in the reaction of Pt(N03)2 with concentrated sulfuric acid in sealed glass ampoules at 400 °C.124 In the crystal structure, Pt2 dumbbells are coordinated by four bidentate-bridging sulfate ions and two axial H20 molecules. The... 

For Elg2Se03 three modifications have been described.133 They all contain dumbbell-shaped EIg22+ ions that are linked by the selenite ions. A common feature of all crystal structures is the formation of channels, which obviously incorporate the lone electron pairs of the selenite ions. 

Two extreme formulations can be considered for such metal chalcogenides ME3 with linear E chains (i) [M4+E2 (E )] implying E% dumbbells as structural fragments (d2 > > d ) and semiconducting behaviour or (ii) (M4+E2 Jo[E ]2, implying chains of equidistant E ions d = di) and metallic properties. The former description clearly applies to ZrSe3134 (d =... 

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