Sequence specificity of Z-DNA formation in oligonucleotides

The sequence specific requirement for B----Z transition in solution was examined in d(CGTGCGCACG), d(CGTACGTACG), d(ACGTACGT) in presence of various Z-inducing factors. Conformational studies show that inspite of the alternating nature of purines and pyrimidines, the aforementioned sequences do not undergo B----Z transition under the influence of NaCl, hexamine cobalt chloride and ethanol. A comparison with the crystal structures of an assorted array of purine and pyrimidine sequences show that the sequence requirement for B----Z transition is much more stringent in solution as compared to the solid state. The disruptive influence of AT base pairs in B to Z transition is discussed.

N-2-(4-Methyl-2-quinolyl)phenyl]acetamide: a P1 structure with Z=4

The title compound, C18H16N2O, crystallizes in the triclinic space group P1, with four independent molecules in the asymmetric unit wherein two molecules have an irregular -ac, -ac, +ap conformation (ap, antiperiplanar; ac, anticlinal), while the other molecules exhibit a different, +ac, +ac, +ap conformation. The planar (r.m.s. deviation = 0.006 A in each of the four molecules) quinoline ring systems of the four molecules are oriented at dihedral angles of 32.8 (2), 33.4 (2), 31.7 (2) and 32.3 (2)degrees with respect to the benzene rings. Intramolecular N-H...N interactions occur in all four independent molecules. The crystal packing is stabilized by intermolecular N-H...O and C-H...O hydrogen bonds, and are further consolidated by C-H...pi and pi-pi stacking interactions centroid-centroid distances = 3.728 (3), 3.722 (3), 3.758 (3) and 3.705 (3) A].

The Church and Its Boundaries : A Study of the Special Commission on Orthodox Participation in the WCC

The relationship between the Orthodox Churches and the World Council of Churches (WCC) became a crisis just before the 8th Assembly of the WCC in Harare, Zimbabwe in 1998. The Special Commission on Orthodox Participation in the WCC (SC), inaugurated in Harare, worked during the period 1999 2002 to solve the crisis and to secure the Orthodox participation in the WCC. The purpose of this study is: 1) to clarify the theological motives for the inauguration of the SC and the theological argumentation of the Orthodox criticism; 2) to write a reliable history and analysis of the SC; 3) to outline the theological argumentation, which structures the debate, and 4) to investigate the ecclesiological questions that arise from the SC material. The study spans the years 1998 to 2006, from the WCC Harare Assembly to the Porto Alegre Assembly. Hence, the initiation and immediate reception of the Special Commission are included in the study. The sources of this study are all the material produced by and for the SC. The method employed is systematic analysis. The focus of the study is on theological argumentation; the historical context and political motives that played a part in the Orthodox-WCC relations are not discussed in detail. The study shows how the initial, specific and individual Orthodox concerns developed into a profound ecclesiological discussion and also led to concrete changes in WCC practices, the best known of which is the change to decision-making by consensus. The Final Report of the SC contains five main themes, namely, ecclesiology, decision-making, worship/common prayer, membership and representation, and social and ethical issues. The main achievement of the SC was that it secured the Orthodox membership in the WCC. The ecclesiological conclusions made in the Final Report are twofold. On the one hand, it confirms that the very act of belonging to the WCC means the commitment to discuss the relationship between a church and churches. The SC recommended that baptism should be added as a criterion for membership in the WCC, and the member churches should continue to work towards the mutual recognition of each other s baptism. These elements strengthen the ecclesiological character of the WCC. On the other hand, when the Final Report discusses common prayer, the ecclesiological conclusions are much more cautious, and the ecclesiological neutrality of the WCC is emphasized several times. The SC repeatedly emphasized that the WCC is a fellowship of churches. The concept of koinonia, which has otherwise been important in recent ecclesiological questions, was not much applied by the SC. The comparison of the results of the SC to parallel ecclesiological documents of the WCC (Nature and Mission of the Church, Called to Be the One Church) shows that they all acknowledge the different ecclesiological starting points of the member churches, and, following that, a variety of legitimate views on the relation of the Church to the churches. Despite the change from preserving the koinonia to promises of eschatological koinonia, all the documents affirm that the goal of the ecumenical movement is still full, visible unity.

Studies on nonlinear optical materials: structure of diphenylmethyl (Z)-1-(1-methylthio-2-nitrovinyl)tetrahydropyrrole-2-carboxylate

C21H22N2045, M r = 398.5, orthorhombic, P212~21, a = 9.799 (1), b = 11.853 (1), c = 17.316(2)/~, V=2011.4A 3, Z=4, Dm=l.320, Dx=1.314Mgm -3, CuKa, A=1.5418A, Iz= 1.63 ram-1, F(000) = 840.0, T = 293 K, R = 0.055 for 1735 significant reflections. In the 1-methylthio-2- nitrovinyl moiety the C--C bond, 1.368 (7)A, is significantly longer than in ethylene, 1.336 (2)/~. The second harmonic generation (SHG) efficiency of this compound is only 0.25 of the urea standard. The correlation between the molecular packing and SHG is discussed.

A glossary of DNA structures from A to Z

The right-handed double-helical Watson-Crick model for B-form DNA is the most commonly known DNA structure. In addition to this classic structure, several other forms of DNA have been observed and it is clear that the DNA molecule can assume different structures depending on the base sequence and environment. The various forms of DNA have been identified as A, B, C etc. In fact, a detailed inspection of the literature reveals that only the letters F, Q, U, V and Y are now available to describe any new DNA structure that may appear in the future. It is also apparent that it may be more relevant to talk about the A, B or C type dinucleotide steps, since several recent structures show mixtures of various different geometries and a careful analysis is essential before identifying it as a 'new structure'. This review provides a glossary of currently identified DNA structures and is quite timely as it outlines the present understanding of DNA structure exactly 50 years after the original discovery of DNA structure by Watson and Crick

Focal plane analysis of the Knox-Thompson algorithm in speckle interferometry

For the specific case of binary stars, this paper presents signal-to-noise ratio (SNR) calculations for the detection of the parity (the side of the brighter component) of the binary using the double correlation method. This double correlation method is a focal plane version of the well-known Knox-Thompson method used in speckle interferometry. It is shown that SNR for parity detection using double correlation depends linearly on binary separation. This new result was entirely missed by previous analytical calculations dealing with a point source. It is concluded that, for magnitudes relevant to the present day speckle interferometry and for binary separations close to the diffraction limit, speckle masking has better SNR for parity detection.

Quinoxaline: Z `=1 form

A new Z' = 1 crystal structure of quinoxaline (or 1,4-diazanaphthalene), C8H6N2, with one-fifth the volume of the earlier known Z' = 5 structure was obtained by means of an in situ cryocrystallization technique.

Application of a modified z-cosy experiment for the analysis of spectra of oriented molecules - the spectrum of cis,cis-mucanonitrile

NMR spectra of cis,cis-mucanonitrile oriented in a liquid crystal have been analysed using the connectivity information obtained from a modified Z-COSY experiment which provided crucial clues for the starting parameters for the iterative analysis. The proton spectra with and without C-13 satellites and the C-13 spectra have thus been interpreted. The indirect spin-spin couplings required for the analyses have been obtained from the corresponding isotropic spectra. The H-1-H-1 and C-13-H-1 dipolar couplings so obtained have been utilized to determine the relative internuclear distances. The results indicate that the molecule is planar. (C) 1994 Academic Press, Inc.

Construction of energy-level diagram of oriented benzene using connectivity information obtained by modified z-cosy experiment

Experiments involving selective perturbation of a transition yield information about the directly connected transitions, which in turn yield information for deriving the parameters of the spin Hamiltonian of oriented molecules. Problems involved with selective perturbation are removed by the use of a two-dimensional experiment, namely, the modified Z-COSY-experiment, The use of this experiment is demonstrated for obtaining the connectivity information and for determining the parameters of the spin Hamiltonian of oriented benzene, a strongly coupled six-spin system

Signals of additional Z ` boson in e(+)e(-) -> W+W- at the ILC with polarized beams

We consider the possibility of fingerprinting the presence of heavy additional Z' bosons that arise naturally in extensions of the standard model such as E-6 models and left-right symmetric models, through their mixing with the standard model Z boson. By considering a class of observables including total cross sections, energy distributions and angular distributions of decay leptons we find significant deviation from the standard model predictions for these quantities with right-handed electrons and left-handed positrons at root s= 800GeV. The deviations being less pronounced at smaller centre of mass energies as the models are already tightly constrained. Our work suggests that the ILC should have a strong beam polarization physics program particularly with these configurations. On the other hand, a forward backward asymmetry and lepton fraction in the backward direction are more sensitive to new physics with realistic polarization due to interesting interplay with the neutrino t-channel diagram. This process complements the study of fermion pair production processes that have been considered for discrimination between these models.

Effect of magnetic field on the binding energy of a hydrogenic donor in a vertical bar z vertical bar(2/3) quantum well

We have calculated the binding energy of a hydrogenic donor in a quantum well with potential shape proportional to \z\(2/3) as a function of the width of the quantum well and the barrier height under an applied uniform magnetic field along the a axis. As the well width decreases, the binding energy increases initially up to a critical well width (which is nearly the same for all magnetic fields) at which there is a turnover. The results are qualitatively similar to those of a hydrogenic donor in a rectangular well. We have also calculated [rho(2)](1/2) and [z(2)](1/2) for the donor electron. [rho(2)](1/2) is found to be strongly dependent on the magnetic field for a given well width and weakly dependent on the well width and the barrier height, for a given value of magnetic field [z(2)](1/2) is weakly dependent on the applied magnetic field. The probability of finding the donor electron inside the well shows a rapid decrease as the well width is reduced at nearly the well width at which the binding energy shows a maximum.

Giant magnetoresistance in lanthanum strontium yttrium manganese oxides (La(1-x)Sr(x-z)YuMnO(3))

Electron transport and magnetic properties of several compositions of the La1-xSx-zYzMnO3 system have been investigated in order to explore the effect of yttrium substitution on the magnetoresistance and related properties of these manganates. Yttrium substitution lowers the T-c and the insulator-metal transition temperature, while increasing the peak resistivity. A comparison of the properties of La1-xSrx-zYzMnO3 with the corresponding La1-xCax-zYzMnO3 compositions shows that the observed properties can be related to the average size of the A-site cations.