crystallites

Glutaric Acid Crystallites

One of the dicarboxylic acids, glutaric acid is a by-product of amino acid metabolism. In humans, a devastating genetic disorder called Glutaric Aciduria interferes with the ability to properly digest protein resulting in the build-up of glutaric acid in the bloodstream. Left undiagnosed and untreated, this condition can damage two nerve clusters in the brain involved in controlling posture and movement, causing serious and permanent disability.

arxiv.org
[1508.04563] Phason space analysis and structure modeling of 100 A-scale dodecagonal quasicrystal in Mn-based alloy

[ Authors ]
Tsutomu Ishimasa, Shuhei Iwami, Norihito Sakaguchi, Ryo Oota, Marek Mihalkovic
[ Abstract ]
The dodecagonal quasicrystal classified into the five-dimensional space group P126/mmc, recently discovered in a Mn-Cr-Ni-Si alloy, has been analyzed using atomic-resolution spherical aberration-corrected electron microscopy, i.e. high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and conventional transmission electron microscopy. By observing along the 12-fold axis, non-periodic tiling consisting of an equilateral triangle and a square has been revealed, of which common edge length is a = 4.560 A. These tiles tend to form a network of dodecagons of which size is (2+Sqrt(3))a ~ 17 A in diameter. The tiling was interpreted as an aggregate of 100 A-scale oriented domains of high- and low-quality quasicrystals with small crystallites appearing at their boundaries. The quasicrystal domains exhibited a densely-filled circular acceptance region in the phason space. This is the first observation of the acceptance region in an actual dodecagonal quasicrystal.

Vitamin C Crystallites

Ascorbic acid, also known by the chemical name L-ascorbic acid, is a water-soluble vitamin that functions as a powerful antioxidant. Although most animals can synthesize vitamin C, others — such as including humans and other primates and guinea pigs — obtain it only through their diets. Vitamin C is commonly found naturally in peppers, citrus fruits, tomatoes, melons, broccoli, and green leafy vegetables such as spinach, turnip, and mustard greens.

Ephedrine Crystallites

Ephedrine is a member of the adrenergic bronchodilator class of drugs that serve to open up the bronchial tubes of the lungs. Since the 1920s, synthetic versions of this drug have been used as a bronchodilator and nasal decongestant, and for controlling urinary incontinence. Although ephedrine is too slow acting to treat acute allergic attacks, it replaces epinephrine in nonemergency treatment of allergic reactions.

arxiv.org
[1508.03609] Antiferromagnetism at T > 500 K in the Layered Hexagonal Ruthenate SrRu2O6

[ Authors ]
C. I. Hiley, D. O. Scanlon, A. A. Sokol, S. M. Woodley, A. M. Ganose, S. Sangiao, J. M. De Teresa, P. Manuel, D. D. Khalyavin, M. Walker, M. R. Lees, R. I. Walton
[ Abstract ]
We report an experimental and computational study of magnetic and electronic properties of the layered Ru(V) oxide SrRu2O6 (hexagonal, P-3 1m), which shows antiferromagnetic order with a N'eel temperature of 563(2) K, among the highest for 4d oxides. Magnetic order occurs both within edge-shared octahedral sheets and between layers and is accompanied by anisotropic thermal expansivity that implies strong magnetoelastic coupling of Ru(V) centers. Electrical transport measurements using focused ion beam induced deposited contacts on a micron-scale crystallite as a function of temperature show p-type semiconductivity. The calculated electronic structure using hybrid density functional theory successfully accounts for the experimentally observed magnetic and electronic structure and Monte Carlo simulations reveals how strong intralayer as well as weaker interlayer interactions are a defining feature of the high temperature magnetic order in the material.