Correspondence e-mail: [email protected] HIV/SIV Nef mediates many cellular processes through interactions with various cytoplasmic and membrane-associated host proteins, including the signalling subunit of the T-cell receptor (TCR ). Here, the crystallization strategy, methods and refinement procedures used to solve the structures of the core domain of the SIVmac239 isolate of Nef (N...

The title mol-ecule, C(15)H(15)Br(2), has crystallographic m2m site symmetry. As a result, all atoms, except for those of the methyl groups, are exactly coplanar. In the crystal structure, there are weak π-π inter-actions with a centroid-centroid distance of 3.8409 (15) Å between symmetry-related mol-ecules, which stack along the c axis.

In the crystal structure of the title compound, C(24)H(6)O, the mol-ecule exhibits point symmetry m but the mirror plane is not utilized as part of the space-group symmetry. The structure contains face-to-face inter-actions between the 2,4-dimethyl-benzyl-idene substituents in which the methyl groups lie directly above the centroids of adjacent benzene rings.

A method is described to produce global phase diagrams for single-component molecular crystals with separable internal and external modes. The phase diagrams present the equilibrium crystalline phase as a function of the coefficients of a general intermolecular potential based on rotational symmetry-adapted basis functions. It is assumed that phase transitions are driven by orientational orderi...

Understanding the behaviour of thermally excited many-particle systems, composed of a single particle type having a well-defined shape and size, is important in condensed matter, notably protein crystallization. Here we observe and explain the origin of local chiral symmetry breaking in a surprisingly simple system of hard Brownian particles: achiral regular triangles confined to two dimensions...

The luminescence spectra of europium (3 + ) doped rare earth oxyhydroxides, REOOH :Eu 3 + (RE = Y and Lu), were studied and analyzed at 77 and 300 K under UV and dye laser excitation. The observed 7 F 0 _ 4 level schemes were simulated with the aid of the phenomenological crystal field theory. The descending symmetry method from C2 v to Cs symmetry was used in the simulation. Good results were ...

In the crystal structure of the title compound, C(4)H(12)N(+)·BH(4) (-), the tetra-methyl-ammonium cations are situated on special positions with site symmetry [Formula: see text]m2. The borohydride anions are situated on special positions with 4mm site symmetry and show rotational disorder around the fourfold axis.

We investigate experimentally the generation of highly directional radiation from a plain two-dimensional photonic crystal structure where an embedded source couples to a photonic crystal band having Bloch modes of even symmetry and negative group velocity. No modification is made to the crystal structure. By virtue of recent studies employing corrugated surface modes, this may be a viable meth...

We study the optical response of a metamaterial surface created by a lattice of split-ring resonators covered with a nematic liquid crystal and demonstrate millisecond timescale switching between electric and magnetic resonances of the metasurface. This is achieved due to a high sensitivity of liquid-crystal molecular reorientation to the symmetry of the metasurface as well as to the presence o...

The standard molecular replacement (MR) protocol involves one-by-one search for molecules composing the asymmetric unit, therefore the non-crystallographic symmetry (NCS) complicates the structure determination. However, the conservation of the oligomeric state in a series of homologues and the use of information about the NCS in the target crystal may help to solve difficult MR problems. A num...