26 research outputs found
Structural and Electronic Properties of a Triangular Lattice Magnet NaPrTe Compared with NaNdTe and NaTbTe
NaPrTe2, NaNdTe2, and NaTbTe2 are found to be triangular lattice magnets with
the alpha-NaFeO2 structure, where lanthanoid atoms with 4f electrons form a
triangular lattice, based on the structural analysis and physical property
measurements of synthesized polycrystalline samples. The alpha-NaFeO2 structure
is a new polymorph of NaPrTe2, which has been reported to crystallize in the
cubic LiTiO2 structure. Polytypism in NaPrTe2 was discussed based on the
structural parameters determined by the Rietveld analysis. NaPrTe2 is suggested
to be in the proximity of the phase boundary between the LiTiO2 and
alpha-NaFeO2 types, as compared to NaNdTe2 and NaTbTe2, indicating that this
compound might be interesting from the perspectives of the dimensional control
of geometrically frustrated lattices. The magnetic susceptibility and heat
capacity data indicated that NaPrTe2 do not show long-range magnetic order or a
spin-glass transition above 2 K.Comment: 6 pages, 7 figure
A 1-bp deletion in Mc1r in a Norway rat (Rattus norvegicus) from Sado Island, Japan gives rise to a yellowish color variant: an insight into mammalian MC1R variants
The melanocortin-1 receptor gene (MC1R) controls production of the pigments eumelanin and pheomelanin. Changes in MC1R lead to variation in coat color in mammals, which can range from entirely black (melanism) to yellowish. In this study, we report a case of a wild-caught Norway rat (Rattus norvegicus) from Sado Island, Japan with a yellowish coat color. Upon sequencing the whole coding region of the Mc1r gene (954 bp), we found a 1-bp deletion at site 337 (c.337del), indicative of a frameshift mutation, which was characterized as a severe loss-of-function or null mutation. A spectrophotometer was used to measure coat color, revealing that the rat had a distinctly lighter coat, based on lightness score, than mice with homozygous similar loss-of-function mutations. This implies that loss-of-function mutations can yield different phenotypes in murine rodents. The loss-of-function-mutant rat exhibited a contrasting coat pattern consisting of darker and lighter colors along its dorsal and ventral sides, respectively. Similar patterns have been observed in homozygous MC1R-deficient mutants in other mammals, implying that the countershading pattern can still be expressed despite the absence of MC1R in the melanocyte
Superior vena cava syndrome caused by a swollen absorbable haemostat after repair of ischaemic mitral regurgitation
Surgicel, an absorbable haemostat, is widely used in cardiovascular surgery. An 81-year-old woman, who was diagnosed with ischaemic mitral regurgitation, underwent mitral valve plasty and coronary artery bypass grafting. On postoperative day two, her superior vena cava (SVC) pressure gradually rose to 38 mmHg and she developed low output syndrome. Emergent surgery revealed that the cause of SVC syndrome was external compression from a haematoma at the posterior surface of the SVC, which formed around the Surgicel
Effects of intracerebroventricular administration of 2-hydroxypropyl-β-cyclodextrin in a patient with Niemann–Pick Type C disease
Niemann–Pick Type C disease (NPC) is an autosomal recessive lysosomal storage disorder characterized by progressive neurological deterioration. Previously, we reported that intravenous administration of 2-hydroxypropyl-β-cyclodextrin (HPB-CD) in two patients with NPC had only partial and transient beneficial effects on neurological function. The most likely reason for HPB-CD not significantly improving the neurological deficits of NPC is its inability to cross the blood–brain barrier. Herein, we describe the effects of intrathecal HPB-CD in an eight-year-old patient with a perinatal onset of NPC, administered initially at a dose of 10 mg/kg every other week and increased up to 10 mg/kg twice a week. Clinically, the patient maintained residual neurological functions for two years, at which time nuclear magnetic resonance spectroscopy showed a decreased choline to creatine ratio and increased N-acetylaspartate to creatine ratio, and positron emission tomography revealed increased standardized uptake values. Total-tau in the cerebrospinal fluid (CSF) was also decreased after two years. No adverse effects were observed over the course of treatment. The CSF concentrations of HPB-CD during the distribution phase after the injections were comparable with those at which HPB-CD could normalize cellular cholesterol abnormality in vitro. Further studies are necessary to elucidate the mechanisms of action of HPB-CD in NPC, and to determine the optimal dose and intervals of HPB-CD injection