Thermal properties of N-alkyl-N-methylpyrrolidinium and N-butylpyridinium fluorometallates and physicochemical properties of their melts

A series of N-alkyl-N-methylpyrrolidinium (RMPyr+, where R = E: ethyl, B: butyl, and H: hexyl) and N-butylpyridinium (BPy+) salts based on the fluorocomplex anions, BF₄⁻, PF₆⁻, SbF₆⁻, NbF₆⁻, TaF₆⁻, and WF₇⁻, have been synthesized and their thermal behavior has been investigated. The melting points of the RMPyr⁺ salts are above room temperature with the trend; BMPyrAF₆ < HMPyrAF₆ < EMPyrAF₆ for the hexafluorocomplex salts. Some of the salts containing BMPyr⁺ and HMPyr⁺ exhibit phase transitions in the solid states. Similar melting points of BPy⁺ salts of PF₆⁻, SbF₆⁻, TaF₆⁻, and WF₇⁻ are observed at around 350 K. Ionic conductivity and viscosity for BMPyrNbF₆ (3.0 mS cm⁻¹ and 164 cP at 328 K) are similar to those for BMPyrTaF₆ (3.0 mS cm⁻¹ and 165 cP at 328 K), resulting from the similarity of the anions in size. The activation energies of ionic conductivity for the NbF₆⁻ and TaF₆⁻ salts are 18 and 20 kJ mol⁻¹, and those for viscosity are 23 and 25 kJ mol⁻¹, respectively calculated by Arrhenius equation in the temperature range between 328 and 348 K. Electrochemical windows of BMPyrNbF₆, BMPyrTaF₆, and BMPyrWF₇ are about 4.0, 5.0 and 3.1 V, respectively

Enpp1 is an anti-aging factor that regulates Klotho under phosphate overload conditions

Control of phosphate metabolism is crucial to regulate aging in mammals. Klotho is a well-known anti-aging factor that regulates phosphate metabolism: mice mutant or deficient in Klotho exhibit phenotypes resembling human aging. Here we show that ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1) is required for Klotho expression under phosphate overload conditions. Loss-of-function Enpp1 ttw/ttw mice under phosphate overload conditions exhibited phenotypes resembling human aging and Klotho mutants, such as short life span, arteriosclerosis and osteoporosis, with elevated serum 1,25(OH)2D3 levels. Enpp1ttw/ttw mice also exhibited significantly reduced renal Klotho expression under phosphate overload conditions, and aging phenotypes in these mice were rescued by Klotho overexpression, a low vitamin D diet or vitamin D receptor knockout. These findings indicate that Enpp1 plays a crucial role in regulating aging via Klotho expression under phosphate overload conditions

Electrochemical behavior of hexafluoroniobate, heptafluorotungstate, and oxotetrafluorovanadate anions in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide room temperature ionic liquid

Electrochemical behavior of hexafluoroniobate (Nb(V)F_6[−]), heptafluorotungstate (W(VI)F_7[−]), and oxotetrafluorovanadate (V(V)OF_4[−]) anions has been investigated in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPyrTFSA) ionic liquid at 298 K by means of cyclic voltammetry and chronoamperometry. Cyclic voltammograms at a Pt electrode showed that Nb(V)F_6[−] anion is reduced to Nb(IV)F_6[2−] by a one-electron reversible reaction. Electrochemical reductions of W(VI)F_7[−] and V(V)OF_4[−] anions at a Pt electrode are quasi-reversible and irreversible reactions, respectively, according to cyclic voltammetry. The diffusion coefficients of Nb(V)F_6[−], W(VI)F_7[−] and V(V)OF_4[−] determined by chronoamperometry are 1.34 × 10[−7], 7.45 × 10[−8] and 2.49 × 10[−7] cm[2] s[−1], respectively. The Stokes radii of Nb(V)F_6[−], W(VI)F_7[−], and V(V)OF_4[−] in BMPyrTFSA have been calculated to be 0.23, 0.38, and 0.12 nm, from the diffusion coefficients and viscosities obtained

Novel excitations near quantum criticality in geometrically frustrated antiferromagnet CsFeCl3

The investigation of materials that exhibit quantum phase transition provides valuable insights into fundamental problems in physics. We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder in the low-pressure phase and a noncollinear structure in the high-pressure phase. The neutron spectrum continuously evolves through critical pressure; a single mode in the disordered state becomes soft with the pressure and it splits into gapless and gapped modes in the ordered phase. Extended spin-wave theory reveals that the longitudinal and transverse fluctuations of spins are hybridized in the modes because of noncollinearity, and previously unidentified magnetic excitations are formed. We report a new hybridization of the phase and amplitude fluctuations of the order parameter near a quantum critical point in a spontaneously symmetry-broken state.ISSN:2375-254

A technique for taping inferior vena cava caudal to the duodenum: duodenal penetration by IVC filter strut after retroperitoneal lymph node dissection—usefulness of the mesenteric approach

Abstract Background Although an inferior vena cava (IVC) filter is used for preventing pulmonary thromboembolism (PTE) in patients with deep vein thrombosis, IVC filter penetration in the duodenum is a rare complication. Case presentation A 35-year-old man had previously undergone retroperitoneal lymph node dissection (RPLND) for testicular cancer and IVC filter placement for prevention of PTE. Esophagogastroduodenoscopy (EGD) for his epigastric pain revealed penetration of the IVC filter in the duodenum. The IVC filter was retrieved through cavotomy, and the duodenal penetration was repaired using EGD clipping. Although it was difficult to mobilize the duodenum due to adhesion resulting from RPLND, the use of a mesenteric approach enabled encircling of the IVC caudal to the duodenum. The mesenteric approach is useful and safe for taping the IVC caudal to the duodenum in cases where it is difficult to mobilize the duodenum. Conclusion IVC taping using the mesenteric approach allowed safe retrieval of the IVC filter after RPLND without postoperative complications