Hg-coordination studies of oligopeptides containing cysteine,histidine and tyrosine by 199mHg-TDPAC

In order to study the interaction of histidine- and tyrosine-containing peptide chains with Hg(II), the nuclear quadrupole interaction (NQI) of ^199mHg in the Hg complexes of the oligopeptides Alanyl–Alanyl–Histidyl–Alanyl–Alanine-amid (AAHAA–NH₂) and Alanyl–Alanyl–Tyrosyl–Alanyl–Alanine-amid (AAYAA–NH₂) was determined by time differential perturbed angular correlation and is compared with previous data on Alanyl–Alanyl–Cysteyl–Alanyl–Alanyl (AACAA–OH). The ^199mHg–NQIs depend on the oligopeptide to Hg(II) stoichiometry and indicate that two-fold and four-fold coordinations occur for the bound Hg(II). This revised version was published online in August 2006 with corrections to the Cover Date.     

The Physical Tourist

I provide a tour of Edinburgh focusing on famous contributors to the history of physics and related sciences, using them as a way to write about particular parts of Edinburgh. I proceed chronologically, from the seventeenth century to the Scottish Enlightenment of the eighteenth century and on to the nineteenth and twentieth centuries. Among the notable individuals I discuss are John Napier (1550–1617), James Gregory (1638–1675), George Sinclair (ca. 1625–1696), Colin Maclaurin (1698–1746), Joseph Black (1728–1799), James Hutton (1726–1797), John James Waterston (1811–1883), William J. Macquorn Rankine (1820–1872), David Brewster (1781–1868), Peter Guthrie Tait (1831–1901), James Clerk Maxwell (1831–1879), Charles Piazzi Smyth (1819–1900), Charles Glover Barkla (1877–1944), Max Born (1882–1970), Edward Victor Appleton (1892–1965), Charles T.R. Wilson (1869–1959), and Peter Higgs (b. 1929).     

N-dimensional non-abelian dilatonic,stable black holes and their Born–Infeld extension

We find large classes of non-asymptotically flat Einstein–Yang–Mills–Dilaton and Einstein–Yang–Mills–Born–Infeld–Dilaton black holes in N-dimensional spherically symmetric spacetime expressed in terms of the quasilocal mass. Extension of the dilatonic YM solution to N-dimensions has been possible by employing the generalized Wu-Yang ansatz. Another metric ansatz, which aided in finding exact solutions is the functional dependence of the radius function on the dilaton field. These classes of black holes are stable against linear radial perturbations. In the limit of vanishing dilaton we obtain Bertotti–Robinson type metrics with the topology of AdS ₂×S ^N–2. Since connection can be established between dilaton and a scalar field of Brans–Dicke type we obtain black hole solutions also in the Brans–Dicke–Yang–Mills theory as well.     

The geometry of the higher dimensional black hole thermodynamics in Einstein–Gauss–Bonnet theory

In this paper, we have studied the geometry of the five-dimensional black hole solutions in (a) Einstein–Yang–Mills–Gauss–Bonnet theory and (b) Einstein–Maxwell–Gauss–Bonnet theory with a cosmological constant for spherically symmetric space time. Formulating the Ruppeiner metric, we have examined the possible phase transition for both the metrics. It is found that depending on some restrictions phase transition is possible for the black holes. Also for Λ = 0 in Einstein–Gauss–Bonnet black hole, the Ruppeiner metric becomes flat and hence the black hole becomes a stable one.     

Geometrothermodynamics of five dimensional black holes in Einstein–Gauss–Bonnet theory

We investigate the thermodynamic properties of 5D static and spherically symmetric black holes in (i) Einstein–Maxwell–Gauss–Bonnet theory, (ii) Einstein–Maxwell–Gauss–Bonnet theory with negative cosmological constant, and in (iii) Einstein–Yang–Mills–Gauss–Bonnet theory. To formulate the thermodynamics of these black holes we use the Bekenstein–Hawking entropy relation and, alternatively, a modified entropy formula which follows from the first law of thermodynamics of black holes. The results of both approaches are not equivalent. Using the formalism of geometrothermodynamics, we introduce in the manifold of equilibrium states a Legendre invariant metric for each black hole and for each thermodynamic approach, and show that the thermodynamic curvature diverges at those points where the temperature vanishes and the heat capacity diverges.     

Mean field methods for atomic and nuclear reactions: The link between time–dependent and time–independent approaches

Abstact: Three variants of mean field methods for atomic and nuclear reactions are compared with respect to both conception and applicability: The time–dependent Hartree–Fock method solves the equation of motion for a Hermitian density operator as initial value problem, with the colliding fragments in a continuum state of relative motion. With no specification of the final state, the method is restricted to inclusive reactions. The time–dependent mean field method, as developed by Kerman, Levit and Negele as well as by Reinhardt, calculates the density for specific transitions and thus applies to exclusive reactions. It uses the Hubbard–Stratonovich transformation to express the full time-development operator with two–body interactions as functional integral over one–body densities. In stationary phase approximation and with Slater determinants as initial and final states, it defines non–Hermitian, time–dependent mean field equations to be solved self–consistently as boundary value problem in time. The time–independent mean field method of Giraud and Nagarajan is based on a Schwinger–type variational principle for the resolvent. It leads to a set of inhomogeneous, non-Hermitian equations of Hartree–Fock type to be solved for given total energy. All information about initial and final channels is contained in the inhomogeneities, hence the method is designed for exclusive reactions. A direct link is established between the time–dependent and time–independent versions. Their relation is non–trivial due to the non–linear nature of mean field methods. Received: 7 January 1998 / Revised version: 20 April 1998     

Consequences of the center–of–mass correction in nuclear mean–field models

We study the influence of the scheme for the correction for spurious center–of–mass motion on the fit of effective interactions for self–consistent nuclear mean–field calculations. We find that interactions with very simple center–of–mass correction have significantly larger surface coefficients than interactions for which the center–of–mass correction was calculated for the actual many–body state during the fit. The reason for that is that the effective interaction has to counteract the wrong trends with nucleon number of all simplified schemes for center–of–mass correction which puts a wrong trend with mass number into the effective interaction itself. The effect becomes clearly visible when looking at the deformation energy of largely deformed systems, e.g. superdeformed states or fission barriers of heavy nuclei. Received: 6 September 1999     

Unrestricted symmetry-projected Hartree-Fock-Bogoliubov calculations for some PF-shell nuclei

Total binding energies and yrast energy spectra of three selected 1p0f–nuclei have been calculated using an unrestricted Hartree–Fock–Bogoliubov approach with symmetry–projection before the variation. The full 1p0f–shell has been used as single–particle basis and the semi–empirical FPD6 interaction as effective Hamiltonian. The results are compared to those of truncated shell–model calculations performed with the OXBASH code. In the middle of the 1p0f–shell the variational method yields energy gains up to 4.5 MeV and thus proves to be far superior than the conventional truncation methods at least if in the latter only up to about 13000 configurations for each spin–isospin combination are admitted. Received: 15 September 1999     

The components of the \gamma^* \gamma^* cross section

We extend our previous treatment of the p cross section based on Gribov's hypothesis to the case of photon–photon scattering. With the aid of two parameters, determined from the experimental data, we separate the interactions into two categories corresponding to short (“soft”) and long (“hard”) distance processes. The photon–photon cross section thus receives contributions from three sectors, soft–soft, hard–hard and hard–soft. The additive quark model is used to describe the soft–soft sector, pQCD the hard–hard sector, while the hard–soft sector is determined by relating it to the system. We calculate and display the behaviour of the total photon–photon cross section and its various components and polarizations for different values of energy and virtuality of the two photons, and discuss the significance of our results. Received: 12 January 2000 / Published online: 6 April 2000     

Microwave excited CO<Subscript>2</Subscript> laser with multiple units using orthogonal electric fields

The third order nonlinear optical properties of 4^′-methoxy chalcone and its derivatives have been investigated using a single-beam Z-scan technique with nanosecond laser pulses at 532 nm. The 4^′-methoxy chalcone and its derivatives are donor–acceptor–acceptor (D–A–A) and donor–acceptor–donor (D–A–D) type intramolecular charge transfer molecules. The nonlinear response in these molecules was found to increase with increase in (a) the electron acceptor strength in D–A–A type and (b) the donor strength of the substituted group in D–A–D type molecules. The χ⁽³⁾ value in these molecules is found to be of the order of 10^-13 esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior was observed with the molecule substituted by a strong electron donor. PACS 42.65.An; 42.70.Nq     

The high frequency magnetic properties of self assembled Fe–Co–Si–N nanogranular thin films

The effect of a variation in Si and N concentration on the microstructure, crystal structure and high-frequency magnetic properties of Fe–Co–Si–N nanogranular thin films was investigated. The films, prepared by rf magnetron sputtering, consisted of nanosized grains of FeCo as well as a Si and N rich intergranular amorphous phase. The Si concentration had a significant effect on the crystal structure of the FeCo phase. The resistivities of the Fe–Co–Si–N films were significantly enhanced by an increase in Si concentration. The resonant frequency of the Fe–Co–Si–N films could be tuned from 0.45 GHz to 2.1 GHz by controlling Si concentration. The N concentration greatly influenced magnetic properties and the variation in resonant frequency is in agreement with Kittel’s equation.     

Study of optical properties and molecular structure of plasma polymerized diethylene glycol dimethyl ether

This paper deals with plasma polymerization processes of diethylene glycol dimethyl ether. Plasmas were produced at 150 mtorr in the range of 10 W to 40 W of RF power. Films were grown on silicon and quartz substrates. Molecular structure of plasma polymerized films and their optical properties were analyzed by Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy. The IR spectra show C–H stretching at 3000–2900 cm^-1, C=O stretching at 1730–1650 cm^-1, C–H bending at 1440–1380 cm^-1, C–O and C–O–C stretching at 1200–1000 cm^-1. The concentrations of C–H, C–O and C–O–C were investigated for different values of RF power. It can be seen that the C–H concentration increases from 0.55 to 1.0 au (arbitrary unit) with the increase of RF power from 10 to 40 W. The concentration of C–O and C–O–C decreases from 1.0 to 0.5 au in the same range of RF power. The refraction index increased from 1.47 to 1.61 with the increase of RF power. The optical gap calculated from absorption coefficient decreased from 5.15 to 3.35 eV with the increase of power. Due to its optical and hydrophilic characteristics these films can be applied, for instance, as glass lens coatings for ophthalmic applications.     

Change of dislocation substructures upon high-cycle fatigue of stainless steel

Methods of transmission electron microscopy of thin foils are used to study the evolution of dislocation substructures in Fe–0.1C–1.7Mn–0.92Ti–18.2Cr–10.4Ni–0.71Si corrosion-proof austenitic steel subject to high-cycle fatigue loading to destruction. Quantitative dependences of the dislocation substructure parameters on the number of loading cycles and distances to the sample surface are established. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 42–45, March, 2009.     

The Nambu–Jona–Lasinio model of light nuclei

The Nambu–Jona–Lasinio model of the deuteron suggested by Nambu and Jona–Lasinio (Phys. Rev. 124 (1961) 246) is formulated from the first principles of QCD. The deuteron appears as a neutron–proton collective excitation, i.e. a Cooper np–pair, induced by a phenomenological local four–nucleon interaction in the nuclear phase of QCD. The model describes the deuteron coupled to itself, nucleons and other particles through one–nucleon loop exchanges providing a minimal transfer of nucleon flavours from initial to final nuclear states and accounting for contributions of nucleon–loop anomalies which are completely determined by one–nucleon loop diagrams. The dominance of contributions of nucleon–loop anomalies to effective Lagrangians of low–energy nuclear interactions is justified in the large N _C expansion, where N _C is the number of quark colours. Received: 10 March 2000     

On the Formation of Nanostructures from Stilbazolium-like Dyes

Nanostructures with well-defined shape and highly monodisperse size were fabricated from model stilbazolium-like dyes with specific molecular structural and conformational characteristics. With the help of absorption and fluorescence optical spectroscopy, the correlated spectroscopy (COSY) and two- dimensional nuclear Overhauser effect spectroscopy (2D NOESY) techniques, along with X-ray diffraction (XRD) measurement, distinctively different aggregation processes of the model molecules are demonstrated. For model dye molecule with linear donor–π system–acceptor (D–π–A) structure, strong D–A pair, and planar conformation, specific intermolecular interaction was identified and special crystal structures as well as spectral properties were observed. For model dye molecules bearing nonlinear D–π–A–π–D structure, weak D–A pair but actual amphiphilic characteristics, a special aggregation process was confirmed and a focused size distribution of the produced nanostructures was obtained.     

The Physical Tourist Physics in Glasgow: A Heritage Tour

I trace the history of the physical and applied sciences, and particularly physics, in Glasgow. Among the notable individuals I discuss are Joseph Black (1728–1799), James Watt (1736–1819), William John Macquorn Rankine (1820–1872), William Thomson, Lord Kelvin (1824–1907), John Kerr (1824–1907), Frederick Soddy (1877–1956), John Logie Baird (1888–1946), and Ian Donald (1910–1987), as well as physics-related businesses.The locations, centering on the city center and University of Glasgow, include sites both recognizable today and transformed from past usage, as well as museums and archives related to the history and interpretation of physics.     

Nonlinearities in the reflection and transmission spectra of the photonic bandgap heterostructures with n–i–p–i crystals

Nonlinear optical properties of photonic crystal heterostructures with embedded n–i–p–i superlattices are investigated. Self-consistent calculations of the transmission and reflection spectra near the defect mode are performed using the transfer-matrix method and taking into account the gain saturation. Analysis of features and output characteristics is carried out for one-dimensional photonic crystal heterostructure amplifiers in the GaAs–GaInP system having at the central part an active “defect” from doubled GaAs n–i–p–i crystal layers. The gain saturation in the active layers in the vicinity of the defect changes the index contrast of the photonic structure and makes worse the emission at the defect mode. Spectral bistability effect, which can be exhibited in photonic crystal heterostructure amplifiers, is predicted and the hysteresis loop and other attending phenomena are described. The bistability behavior and modulation response efficiency demonstrate the potential possibilities of the photonic crystal heterostructures with n–i–p–i layers as high-speed optical amplifiers and switches.      

Calculation of open p-shell atoms in the algebraic approach of the Hartree–Fock method

Highly precise calculations of analytical Hartree–Fock orbitals and energies have been performed within the limits of the Roothaan–Hartree–Fock atomic theory (Roothaan–Bagus method) for all open p-shell atoms of the Periodic Table. They were calculated in an algebraic approach using Slater-type atomic orbitals (AOs) as basis functions. Nonlinear parameters (orbital exponents) of AOs were optimized with exceptional accuracy by second-order methods. As a result, it was possible to satisfy exactly the virial relation (10^–14–10^–17) with calculated atomic term energies being close to the Hartree–Fock limit.     

Generation of multi-axis Laguerre–Gaussian beams from?geometric modes of a hemiconfocal cavity

We study the transformation of multi-axis Laguerre–Gaussian beams from optical beams comprising Hermite–Gaussian modes with ray–wave duality. By use of cylindrical lenses, Hermite–Gaussian modes can be transformed into Laguerre–Gaussian modes possessing optical orbital angular momentum. The superposed Hermite–Gaussian modes localized on geometric trajectories are generated from a degenerate hemiconfocal cavity and transformed into multi-axis Laguerre–Gaussian beams. Experimental results of the structured beams are systematically manipulated and in good agreement with theoretical analyses.     

Whole-body distribution of <Superscript>14</Superscript>C-labeled silica nanoparticles and submicron particles after intravenous injection into Mice

We analyzed the whole-body distribution of ¹⁴C–ADP-labeled silica nanoparticles (¹⁴C–ADP–SiO₂ nanoparticles) and submicron particles (¹⁴C–ADP–SiO₂ submicron particles) after intravenous injection into ICR mice. The ¹⁴C–ADP–SiO₂ nanoparticles and submicron particles were synthesized before the injection and the particle size was 19.6 and 130 nm, respectively. Similarly, the shape was spherical and the crystallinity was amorphous. After the synthesis, we injected mice with the ¹⁴C–ADP–SiO₂ nanoparticles or the ¹⁴C–ADP–SiO₂ submicron particles and dissected tissues after 1, 2, 4, 8 and 24 h. The radioactivity in the tissues was measured with a liquid scintillation counter. As a result, the retention percentage in bone, skin, lymph nodes, and the digestive mixture was at least twofold higher in the ¹⁴C–ADP–SiO₂ nanoparticles-exposed mice, whereas the retention percentage in the kidney was statistically higher in the ¹⁴C–ADP–SiO₂ submicron particles-exposed mice. Both types of ¹⁴C–ADP–SiO₂ particles mainly translocated to the muscle, bone, skin, and liver, but hardly translocated to the brain and olfactory bulb. Furthermore, the ¹⁴C–ADP–SiO₂ nanoparticles had a higher retention percentage (62.4 %) in the entire body at 24-h post-injection than did the ¹⁴C–ADP–SiO₂ submicron particles (50.7 %). Therefore, we suggested that the ¹⁴C–ADP–SiO₂ nanoparticles might be more likely than the ¹⁴C–ADP–SiO₂ submicron particles to be retained in the body, and consequently they might be gradually accumulated by chronic exposure.