Proton and α-particle impactM-shell ionization of atoms in binary encounter approximation

M-shell ionization cross sections for atoms due to the impact of proton and α-particles have been calculated in the binary encounter approximation. The effects of Coulomb deflection of the incident projectile and increase in binding of the target electron have been investigated. Roothan-Hartree-Fock velocity distribution for the target electrons has been used in the present work. The calculated cross-sections have been compared with experimental results and other theoretical calculations wherever available. The present calculations give a good account of experimental observations.     

D-Ala-D-lac binding is not required for the high activity of vancomycin dimers against vancomycin resistant enterococci

Covalent dimerization and oligomerization of vancomycin is an important and extensively used strategy to develop analogues active against vancomycin resistant enteroccoci (VRE). Here, we have carried out investigations to probe the role of peptide binding (Lys-d-Ala-d-Lac) in the high anti-VRE activities of covalently linked vancomycin dimers. Covalent dimers of damaged vancomycin (desleucyl) were prepared, and their anti-VRE activities and binding affinities toward various model peptides were measured. Despite the dramatic loss in affinity toward several model peptides in comparison to the corresponding intact vancomycin dimers, these damaged dimers maintained good activity against VRE. These results strongly suggest that the high anti-VRE activities of covalent vancomycin dimers are conferred from mechanisms other than Lys-d-Ala-d-Lac binding.     

Determination of vorticity,gradients of flow parameters and curvature of stream-lines behind unsteady curved shock waves

In this paper the gradients of flow parameters and the expression for vorticity vector behind three-dimensional unsteady curved shock waves in fluids obeying anarbitrary equation of state have been explicitly determined. A transformation of coordinates defined by Taub [1](¹), has been used and various conservation equations have been obtained in the new coordinate system, assuming the dissipative mechanisms such as viscosity and heat-conduction as absent. The flow quantities on the upstream side of the shock are assumed to be uniform and known and those on its downstream side have been determinedin principle in terms of known quantities for the flow obeying anarbitrary equation of state. For the flow of a perfect gas all the unknown quantities have been explicitly calculated in terms of known quantities. The derivatives of entropy and curvature of stream-lines behind the unsteady shock wave have also been explicitly determined.     

A best approximation property of discrete quadratic interpolatory splines

We investigate the following problem in this paper: where there is an unique 1-periodic discrete quadratic spline s∈S(3,p,h) satisfying certain interpolatory condition for a 1-periodic discrete function defined on [0,1]_h. The anwser is affirmative.     

Null points in the zero-field splitting of magnetic impurity levels

The temperature dependence of the zero-field splitting in CdCl₂ : Mn²⁺ is studied in terms of the effect of splitting due to electron-phonon interaction (SEPI) and from that a temperature called the “null point” is obtained for which the effective interaction $\text{D{S}{}^2{}_{\mathrm{z}}\text{?}\text{1}\text{2}\text{S(S + 1)}}$ vanishes.     

Linear scaling of hyperfine- and superhyperfine interactions

The transfer of an electron from the occupied 2s(F^?) to the empty 4s (Mn²⁺-F^? by lattice-vibrational modulation of attractive nuclear potential is discovered to give rise to the correct reduction of the magnitude of hyperfine interaction of Mn²⁺ ion accompanied by a reduction of superhyperfine coupling of ¹⁹F. This predicted effect is in accord with the experiments in LiF:Mn²⁺ and KMgF₃:Mn²⁺.     

Momentum-density distributions for positron annihilation in manganese and cobalt

A band-structure calculation of positron-annihilation momentum-density distributions and angular correlations have been performed in Mn and Co. The momentum-density results in Mn and the angular correlations in Mn and Co are presented as a preliminary report.     

Effects of biquadratic exchange interaction on dynamic susceptibility in Heisenberg ferromagnet

The Green function technique has been employed to study the dynamic susceptibility of a spin-1 system above the Curie temperature. Bilinear and biquadratic terms have been added in writing the Hamiltonian of the system. Higher order Green functions have been decoupled by RPA and Callen type decouplings. The dependence of spin wave energy, intensity and susceptibility on wavevector and biquadratic parameter have been studied.     

On the third order elastic constants of AgCl-AgBr mixed system

Lowdin's many body effect is accounted to explain the violation of Cauchy's relation (C₁₂=C₄₄) in silver halides. Lundqvists potential model with many body effect has been used to evaluate the third order elastic constants of AgCl and AgBr. A modified Lundqvist potential model is used to calculate the third order elastic constants for the simple AgCl- AgBr mixed system with varying concentration of AgCl and AgBr.     

Voltammetric Detection of Aqueous Glyphosate on a Copper and Poly(Pyrrole)-electromodified Activated Carbon Fiber

Aqueous glyphosate (GLYP) was voltammetrically detected using a Cu-(poly)pyrrole composite electrochemically deposited on activated carbon fiber for the first time in a single-step method. Differential pulse voltammetry indicated good linearity (R² = 0.9902) in the response over 0.02–12 mg L⁻¹ range, with a low limit of detection (0.01 mg L⁻¹). The sensor exhibited reproducibility for soil and fruit samples (RSD values = 2.41 and 3.87%, respectively). The response showed repeatability over 100 consecutive measurements. The response was also unaffected by the interfering substances containing the same functional groups as in GLYP and its metabolite. The method described in this study is facile.