Dumbbell shape

Section 1 1 A review of some fundamental knowledge about atoms and electrons leads to a discussion of wave functions, orbitals, and the electron con figurations of atoms Neutral atoms have as many electrons as the num ber of protons m the nucleus These electrons occupy orbitals m order of increasing energy with no more than two electrons m any one orbital The most frequently encountered atomic orbitals m this text are s orbitals (spherically symmetrical) and p orbitals ( dumbbell shaped)... 

As an aside, when a large liquid droplet is broken up by shear stress, it tends initially to elongate into a dumbbell shape, which determines the particle size of the two large droplets formed. Then, the neck in the center between the ends of the dumbbell may explode or shatter. This would give a debris of particle sizes which can be quite different than the two major particles produced. 

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

As yet, models for fluid membranes have mostly been used to investigate the conformations and shapes of single, isolated membranes, or vesicles [237,239-244], In vesicles, a pressure increment p between the vesicle s interior and exterior is often introduced as an additional relevant variable. An impressive variety of different shapes has been found, including branched polymer-like conformations, inflated vesicles, dumbbell-shaped vesicles, and even stomatocytes. Fig. 15 shows some typical configuration snapshots, and Fig. 16 the phase diagram for vesicles of size N = 247, as calculated by Gompper and Kroll [243]. 

Hantel,/. dumbbell, hantelfdrmig, a. dumbbell-shaped. Hantelmodell, n. dumbbell model, hanthaben, v.t. hantieren, v.t. hantieren, v.t. work, handle, manipulate,... 

The injection and holding pressures were 100 MPa and 50 MPa, respectively. For thick (DIN 53455 Form 3) and thin (cut from the plates) dumbbell-shaped samples, an average shear rate of 230 s was kept constant. 

What do orbitals look like There are four different kinds of orbitals, denoted s, p, d, and f] each with a different shape. Of the four, we ll be concerned primarily with s and p orbitals because these are the most common in organic and biological chemistry. The s orbitals are spherical, with the nucleus at their center p orbitals are dumbbell-shaped and four of the five d orbitals are doverleaf-shaped, as shown in Figure 1.3. The fifth d orbital is shaped like an elongated dumbbell with a doughnut around its middle. 

Figure 1.3 Representations of s, p, and d orbitals. The s orbitals are spherical, the p orbitals are dumbbell-shaped, and four of the five d orbitals are cloverleafshaped. Different lobes of p orbitals are often drawn for convenience as teardrops, but their true shape is more like that of a doorknob, as indicated.

Figure 1.5 Shapes of the 2p orbitals. Each of the three mutually perpendicular, dumbbell-shaped orbitals has two lobes separated by a node. The two lobes have different algebraic signs in the corresponding wave function, as indicated by the different colors.

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... 

Spontaneous nuclear fission takes place when the natural oscillations of a heavy nucleus cause it to break into two nuclei of similar mass (Fig. 17.21). We can think of the nucleus as distorting into a dumbbell shape and then breaking into two smaller nuclei. An example is the spontaneous disintegration of americium-244 into iodine and molybdenum ... 

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... 

Strictly the terms brittle and tough fracture can only be applied to failure under carefiilly specified test conditions. That is to say that the statement that a glassy polymer, such as poly(methyl methacrylate), undergoes brittle fracture at ambient temperatures needs qualifying test conditions must be stated. These are usually that the material has been formed into a dumbbell shaped specimen. 

FIGURE 9.9 Small dumbbell-shaped sample of recombinant resilin prepared with embedded fine stainless steel mesh tabs (left) and being tested in phosphate-buffered saline (PBS) (right). 

All tensile and stress-relaxation measurements were done using an Instron Tensile tester. The samples were cut into the dumbbell shape corresponding to the ASTM D412 type C model (total length 4.5 in. straight part 1.5 in. width 0.25 in.). 

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. 

The two network precursors and solvent (if present) were combined with 20 ppm catalyst and reacted under argon at 75°C to produce the desired networks. The sol fractions, ws, and equilibrium swelling ratio In benzene, V2m, of these networks were determined according to established procedures ( 1, 4. Equilibrium tensile stress-strain Isotherms were obtained at 25 C on dumbbell shaped specimens according to procedures described elsewhere (1, 4). The data were well correlated by linear regression to the empirical Mooney-Rivlin (6 ) relationship. The tensile behavior of the networks formed In solution was measured both on networks with the solvent present and on networks from which the oligomeric PEMS had been extracted. 

In summary, results of in vivo experiments showed the effectiveness of carbosilane dendrimers having clustered Pk carbohydrate moieties, and the complete neutralization potency against STL-II was discovered when dumbbell-shaped dendrimers were identified as potent candidate inibitors. Although the precise mechanism of action remains to be elucidated, this type of inhibitor provided a new strategy for the detoxification of SLTs present in circulation. 

Figure 11 The dumbbell shaped Au24+ ion surrounded by sulfate groups in the crystal...

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. 

Reaction (Scheme 2) of salt 5-2PF6 with an excess of 6, in the presence of the macrocydic polyether BPP34C10, provided1181 [BPP34C10-7] [PF6]4 via a threading-followed-by-stoppering approach.1231 This rotaxane incorporates a free 4,4-bipyridinium recognition site within its dumbbell-shaped compo-... 

Rotaxanes are made of dumbbell-shaped and ring components which exhibit some kind of interaction originating from complementary chemical properties. In rotaxanes containing two different recognition sites in the dumbbell-shaped component it is possible to switch the position of the ring between the two stations by an external stimu-... 

If l = 1, then the orbital is called a p-orbital with two lobes of high electron density on either side of the nucleus, for an hourglass or dumbbell shape. 

ABA triblock copolymers, sometimes referred to as dumbbell shaped copolymers when B is a linear macromolecule. 

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