Structure and dynamics of tail-free discotic liquid crystals: Simulations of fluorinated triphenylene.

Recently, a large family of at least 14 discotic liquid crystals was discovered that are exceptions to the conventional paradigm that discotic mesogens tend to feature long, flexible tails on their periphery. To understand why these materials are liquid crystals, as well as the structural determinants of discotic phase behavior, we studied a group of closely related small tail-free disk-like molecules, including both mesogenic and non-mesogenic compounds differing only in the position of a single fluorine substituent. The rigidity and structural simplicity of these molecules make them well suited to for study by large, fully all-atom simulations.

Evaluating dose ratio of subcutaneous to intravenous immunoglobulin therapy among patients with primary immunodeficiency disease switching to 20% subcutaneous immunoglobulin therapy.

Background: Current prescribing information recommends that physicians apply a dose ratio of 1.37:1 (1.53:1 prior to January 2015) in the United States (US) when switching patients with primary immunodeficiency disease (PI) from intravenous (IVIG) therapy to most subcutaneous therapy ([SCIG], except the 10% SCIG human hyaluronidase and immune globulin).

Second harmonic light scattering induced by defects in the twist-bend nematic phase of liquid crystal dimers.

The nematic twist-bend (NTB) phase, exhibited by certain thermotropic liquid crystalline (LC) dimers, represents a new orientationally ordered mesophase - the first distinct nematic variant discovered in many years. The NTB phase is distinguished by a heliconical winding of the average molecular long axis (director) with a remarkably short (nanoscale) pitch and, in systems of achiral dimers, with an equal probability to form right- and left-handed domains. The NTB structure thus provides another fascinating example of spontaneous chiral symmetry breaking in nature.

Polar structure of disclination loops in nematic liquid crystals probed by second-harmonic-light scattering.

Angle-resolved, second-harmonic-light scattering (SHLS) measurements are reported for three different classes of thermotropic nematic liquid crystals (NLCs): polar and nonpolar rodlike compounds and a bent-core compound. Results revealing well-defined scattering peaks are interpreted in terms of the electric polarization induced by distortions of the nematic orientational field ("flexopolarity") associated with inversion wall defects, nonsingular disclinations, analogous to Neel walls in ferromagnets, that often exhibit a closed loop morphology in NLCs. Analysis of the SHLS patterns based on this model provides a "proof-of-concept" for a potentially useful method to probe the flexopolar properties of NLCs.

Tetranaphthyleno[5,6-bcd:11,12-b'c'd':17,18-b''c''d'':23,24-b'''c'''d''']tetrafuran.

The title compound, C(40)H(16)O(4) or [C(10)H(4)O](4), is a planar tetrameric cyclooligomer which crystallizes in the monoclinic space group P2(1)/n. The compound is located on an inversion center with the asymmetric unit consisting of half of the molecule. The compound displays an interesting packing structure, where the cyclooligomer displays both layered packing with respect to nearest neighbors and a rotation of adjacent planar rings that results in additional interactions.