An Unpublished Letter of Adam Smith

Smith, Adam

doi:10.2307/2223068

Cited by 9 publications

(11 citation statements)

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“…Helix geometry analysis: Analysis of the helix geometry was performed by using the PS program. [52] The PS program determines the parametric equations of a circle that defines the helix axis by minimizing the variance in the distance from the axis to atoms in the polypeptide chain. Here the variance of the distance of the carbonyl carbon atoms to the helix axis was minimized.…”

Section: Discussionmentioning

confidence: 99%

Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

et al. 2011

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The crystal structure of a complex between the pro-survival protein Bcl-xL and an α/β-peptide 21-mer is described. The α/β-peptide contains six β-amino acid residues distributed periodically throughout the sequence and adopts an α-helix-like conformation that mimics the bioactive shape of the Puma BH3 domain. The α/β-peptide forms all of the noncovalent contacts that have previously been identified as necessary for recognition of the pro-survival protein by an authentic BH3 domain. Comparison of our α/β-peptide:Bcl-xL structure with structures of complexes between native BH3 domains and Bcl-2 family proteins reveals how subtle adjustments, including variations in helix radius and helix bowing, allow the α/β-peptide to engage Bcl-xL with high affinity. Geometric comparisons of the BH3-mimetic α/β-peptide with α/β-peptides in helix-bundle assemblies provide insight on the conformational plasticity of backbones that contain combinations of α- and β-amino acid residues. The BH3-mimetic α/β-peptide displays pro-survival protein-binding preferences distinct from those of Puma BH3 itself, even though these two oligomers have identical side chain sequences. Our results suggest origins for this backbone-dependent change in selectivity.

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Section: Discussionmentioning

confidence: 99%

Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

et al. 2011

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“…Both the overlap and spin-orbit elements may be evaluated readily by the "n-function" expansion technique of Lowdin. 5 As an example of this we consider the terms in the expression for the spin-orbit elements in the particularly simple case where the u's transform like a J'=~, mz = 2 state. From E«1.…”

Section: Comments and Conclusionmentioning

confidence: 99%

Spin-Orbit Effects in theFandKBands of Colored Alkali Halides

Smith¹

1972

Phys. Rev. B

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The effect of the spin-orbit interaction in the bound excited I 4 states of the F center is investigated within the framework of the semicontinuum F-center model. Assuming the K band arises from allowed transitions, expressions for the K-band spin-orbit splitting and the F-K spin-orbit configuration interaction are found using vacancy-centered F-center model wave functions orthogonalized to the core states of neighboring ions. A simple physical picture for the variation of the spin-orbit splitting with state of excitation is developed and the spin-orbit splitting of the highly excited states is shown to vary as the inverse cube of the principal quantum number. A detailed numerical calculation for the RbC1 F center is carried out. The predictions include an F-band splitting of -15.3 x10 3 eV, a K-band splitting of -2.2 x10+ eV, and an F-K configuration interaction parameter of -3, 8x10 3 eV. These results are in good agreement with quantities derived from magneto-optic experiments. %. INTRODUCTIONThe optical absorptions and emissions for electronic transitions of color centers in solids are generally broadened into bands by the electronphonon interaction. The typical optical spectrum of a color center consequently does not show any of the fine structure that may be present in the center's electronic energy levels. However, in the past few years it has been found that this fine structure may be resolved by external-field techniques. ' " These techniques were first applied to the F center in magneto-optical studies that disclosed an unexpectedly large and negative spinorbit splitting in the E band. ' ' In addition, these investigations yielded unrelaxed excited-state g factors, ' and the relative contribution of cubic and noncubic lattice vibrations to the broadening of the F band Spin-orbit structure has also been found in magneto-optic experiments" ' on the K-band absorption"' of the E center. This is of particular interest because of the controversy surrounding assignment of this band to specific transitions. In the present paper we shall investigate the theory of spin-orbit effects for this absorption.Briefly, the K band is a small absorption found in association with the F band in many alkali halides. Typically it lies a few tenths of an eV higher in energy than the F band, but has an oscillator strength roughly one-tenth as great. '~T he K band is best resolved in RbCl, and in those salts in which it is not resolved it probably comprises the long high-energy tail of the E band. There has been much speculation as to the nature of the K absorption, but Chiarotti and Grassano" established by modulation of the F-center ground-state population that the K band involves transitions from the F-center ground state. Independent evidence for this is given by the observations of d'Aubignd and Gareyte" and of Henry' that magneto-optic effects in the K band have the same spin-relaxation time as the F-center ground state. The situation with respect to the final excited state involved is not as clear. The two most widely disc...

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“…The role of energy balance between the apex and body of the emitter as well as the dynamic thermal effects such as the Nottingham cooling effect may also need to be taken into consideration. 29 The emission-site density maps for a 3-mm 2 surface area of a boron-doped MWNT film with 20% nanotube loading in polystyrene is shown in Fig. 9(a).…”

Section: Cnt-polymer Compositesmentioning

confidence: 99%

Design of carbon nanotubes for large‐area electron field‐emission cathodes

Smith¹,

Silva²

2008

J Soc Info Display

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Abstract— Electron field‐emission displays offer a viable option for the next generation of flat‐panel screens. Boasting high‐quality images in terms of good color saturation, fast refresh rate, and high brightness, these displays have the potential to offer above and beyond what the current market leaders, LCD and plasma. However, for the realization of such a new display disrupting the incumbent LCD and plasma displays, not only does the image quality need to be better, but fabrication costs and suitable manufacturing processes need to be in place at reduced cost. Many viable cathode materials have been proposed in recent years, one of which being the use of carbon nanotubes (CNTs) in various forms (aligned growth, screen printing, and polymer matrix). In this review, a series of recent experiments investigating the field‐emission characteristics of carbon‐nanotube systems for possible use in the display industry is presented.

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An Unpublished Letter of Adam Smith

Cited by 9 publications

References 0 publications

Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

Spin-Orbit Effects in theFandKBands of Colored Alkali Halides

Design of carbon nanotubes for large‐area electron field‐emission cathodes

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An Unpublished Letter of Adam Smith

Cited by 9 publications

References 0 publications

Structural Basis of Bcl‐xL Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

Structural Basis of Bcl‐xL Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

Spin-Orbit Effects in theFandKBands of Colored Alkali Halides

Design of carbon nanotubes for large‐area electron field‐emission cathodes

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Product

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Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design

Structural Basis of Bcl‐x_L Recognition by a BH3‐Mimetic α/β‐Peptide Generated by Sequence‐Based Design