Energy levels of 56Co studied by the 58Ni(d, α)56Co reaction near 0°

Tensor analyzing powers, T₂₀, of outgoing α-particles in the ⁵⁸Ni($\text{d}$, α)⁵⁶Co reaction at detection angles near 0° have been measured for excited states in ⁵⁶Co for beam energies of 6.75, 7.0, 7.5, 9.0 and 9.5 MeV. Thirty-seven spin-parity combinations for ⁵⁶Co excited states have been deduced. Previous J^π ambiguities for 11 of these states have been eliminated, and results in conflict with existing assignments for the levels at 3.235 and 3.378 MeV have been obtained. A search for 0⁺ states was carried out from angular distribution measurements at forward angles of the unpolarized (d, α) reaction. The combined results from this and previous experiments were found to be in reasonable agreement with calculated level schemes.     

Stereoselective rhodium-catalyzed amination of alkenes

The first stereoselective rhodium-catalyzed intermolecular aziridination and C-H amination of alkenes to produce chiral carbamate-protected aziridines and allylic amines is described. Good yields and diastereoselectivities were achieved using a readily available chiral N-tosyloxycarbamate and stoichiometric amount of the alkene substrate. Furthermore the protecting group is easy to cleave under mild reaction conditions.     

The selection rule in (d, α) reactions leading to 0+ antianalogue states in odd-odd nuclei

We point out that, in many cases, anti-analogue 0⁺ states cannot be populated in )d, α) reactions. This results from the particular isospin structure of the anti-analogue, and may well be new, useful, tool to aid in the identification of such states. A particular example arising in the ⁴² Ca (d, α) reaction is generalized in a straightforward way.     

Spin-parity assignments for 66Cu levels via the 68Zn(d, α)66Cu reaction

The ⁶⁸Zn($\text{d}$, α)⁶⁶Cu reaction populating low-lying states in ⁶⁶Cu has been studied at θ_lab = 4° using deuteron beams in the energy range 9.0 to 10.5 MeV. Tensor analyzing powers were calculated and natural- or unnatural-parity assignments were made for thirteen states in ⁶⁶Cu. By combining these results with existing limits unambiguous J^π assignments of 2⁺, 2⁺, 2⁺ and 1⁺ have been made for the levels at 186, 465, 822 and 1344 keV respectively. The previous tentative assignments to seven other levels have been confirmed while that for the 1247 keV level has been shown to be incorrect. The identification of the quartet of levels based on the $\text{π(}\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{)v(}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ configuration has been confirmed.     

A generalization of a bivariate chi‐square distribution

This article deals with the distributions of the sum, the product and the quotient of two generalized bivariate chi‐square variates by first suggesting a generalization of a bivariate chi‐square distribution.     

Optimizing winter road maintenance operations under real-time information

This paper introduces a real-time optimization model that can be used by maintenance managers to develop and evaluate alternative resources allocation plans for winter road maintenance operations. The model takes into account a wide range of road and weather condition factors such as road network topology, road class, weather forecasts, and contractual service levels, and produces a vehicle dispatch schedule that is optimal with respect to operating costs and quality of service. The model is then used in an analysis on a realistic case to illustrate the potential impact of improved information on winter maintenance operations.     

The electronic Raman spectrum of cobalt doped MgO

The energies of the ⁴T_1g states of Co²⁺ as a dilute substitutional impurity in MgO relative to the ground Λ_6g doublet have been found by low temperature Raman spectroscopy to be two Λ_8g states at 305 ± 3 cm^?1 and 930 ± 3 cm^?1; the remaining Λ_7g energy is predicted to be in the 980–1010 cm^?1 range the corresponding Λ_6g → Λ_7g Raman transition being weak and buried in the extensive two-phonon background. A second-order perturbation calculation which couples the spin-orbit states to both E_g and T_2g modes of vibration gives a weak but important Jahn-Teller stabilization energy for the Λ_8g states.     

Modeling negative cooperativity in streptavidin adsorption onto biotinylated microtubules

The nanoscale architecture of binding sites can result in complex binding kinetics. Here, the adsorption of streptavidin and neutravidin to biotinylated microtubules is found to exhibit negative cooperativity due to electrostatic interactions and steric hindrance. This behavior is modeled by a newly developed kinetic analogue of the Fowler-Guggenheim adsorption model. The complex adsorption kinetics of streptavidin to biotinylated structures needs to be considered when these intermolecular bonds are employed in self-assembly and nanobiotechnology.     

A Chirally Stable,Atropoisomeric, Cα‐Tetrasubstituted α‐Amino Acid: Incorporation into Model Peptides and Conformational Preference

A variety of model peptides, including four complete homologous series, to the pentamer level, characterized by the recently proposed binaphthyl‐based, axially chiral, C^α‐tetrasubstituted, cyclic α‐amino acid Bin, in combination with Ala, Gly, or Aib residues, was synthesized by solution methods and fully characterized. The solution conformational propensity of these peptides was determined by FT‐IR absorption and ¹H‐NMR techniques. Moreover, the molecular structures of the free amino acid (S)‐enantiomer and an N^α‐acylated dipeptide alkylamide with the heterochiral sequence ‐(R)‐Bin‐Phe‐ were assessed in the crystal state by X‐ray diffraction. Taken together, the results point to the conclusion that β‐bends and 3₁₀ helices are preferentially adopted by Bin‐containing peptides, although the fully extended conformation would also be adopted in solution by the short oligomers to some extent. We also confirmed the tendency of (R)‐Bin to fold a peptide chain into right‐handed bend and helical structures. The absolute configuration of the Bin residue(s) was correlated with the typically intense exciton‐split Cotton effect of the ¹B_b binaphthyl transition near 225 nm.