Experiments on both single-crystal graphite and highly oriented pyrolytic graphite indicate that for 60Ͻ T Ͻ 300 K, C 60 forms single-layer islands of close-packed molecules at low coverages. Low-energy electrondiffraction measurements on the single crystal indicate that there is almost no preferred orientation of the C 60 lattice relative to the graphite lattice, producing continuous diffraction rings. A slight preference for the C 60 lattice oriented at 30°relative to the graphite lattice is explained as originating in the preference for the C 60 islands to nucleate and align at step edges, observed with scanning tunneling microscopy and low-energy electron microscopy. The energetics of this C 60 layer were investigated using the Novaco-McTague theory of epitaxial orientation, which found several minimum-energy angles near the experimental C 60 -C 60 spacing, inconsistent with the experiment and suggesting an extremely small C 60 -graphite corrugation. The thermal expansion of this "floating solid" C 60 lattice for 60Ͻ T Ͻ 120 K was compared to theoretical models using previously formulated C 60 -C 60 pair potentials. The calculated values, assuming perfect two-dimensional layers of spherical C 60 , are significantly smaller than the measured values, suggesting that additional thermal excitations, such as those involving molecular orientations, are present in this temperature range.

In patients with urinary magnesium wasting, oral and intravenous supplementation often fail to adequately improve serum magnesium levels. Glucose intolerance and diabetes mellitus frequently accompany hypomagnesemia. Clinical trials examining inhibitors of the type 2 sodium glucose cotransporter (SGLT2) show small but significant increases in serum magnesium levels in diabetic patients. This report describes dramatic improvement in serum magnesium levels and associated symptoms after initiating SGLT2 inhibitor therapy in 3 patients with refractory hypomagnesemia and diabetes. Each patient received a different SGLT2 inhibitor: canagliflozin, empagliflozin, or dapagliflozin. One patient discontinued daily intravenous magnesium supplements and exhibited higher serum magnesium levels than had been achieved by magnesium infusion. 2 of the 3 patients exhibited reduced urinary fractional excretion of magnesium, suggesting enhanced tubular reabsorption of magnesium. These observations demonstrate that SGLT2 inhibitors can improve the management of patients with otherwise intractable hypomagnesemia, representing a new tool in this challenging clinical disorder.

on the behalf of the Italian PBC RegistryBaCKgRoUND aND aIMS: Liver fibrosis holds a relevant prognostic meaning in primary biliary cholangitis (PBC). Noninvasive fibrosis evaluation using vibration-controlled transient elastography (VCTE) is routinely performed. However, there is limited evidence on its accuracy at diagnosis in PBC. We aimed to estimate the diagnostic accuracy of VCTE in assessing advanced fibrosis (AF) at disease presentation in PBC. appRoaCH aND ReSUltS: We collected data from 167 consecutive treatment-naïve PBC patients who underwent liver biopsy (LB) at diagnosis at six Italian centers. VCTE examinations were completed within 12 weeks of LB. Biopsies were scored by two blinded expert pathologists, according to the Ludwig system. Diagnostic accuracy was estimated using the area under the receiver operating characteristic curves (AUROCs) for AF (Ludwig stage ≥III). Effects of biochemical and clinical parameters on liver stiffness measurement (LSM) were appraised. The derivation cohort consisted of 126 patients with valid LSM and LB; VCTE identified patients with AF with an AUROC of 0.89. LSM cutoffs ≤6.5 and >11.0 kPa enabled to exclude and confirm, respectively, AF (negative predictive value [NPV] = 0.94; positive predictive value [PPV] = 0.89; error rate = 5.6%). These values were externally validated in an independent cohort of 91 PBC patients (NPV = 0.93; PPV = 0.89; error rate = 8.6%). Multivariable analysis found that the only parameter affecting LSM was fibrosis stage. No association was found with BMI and liver biochemistry. CoNClUSIoNS:In a multicenter study of treatment-naïve PBC patients, we identified two cutoffs (LSM ≤6.5 and >11.0 kPa) able to discriminate at diagnosis the absence or presence, respectively, of AF in PBC patients, with external validation. In patients with LSM between these two cutoffs, VCTE is not reliable and liver biopsy should be evaluated for accurate disease staging. BMI and liver biochemistry did not affect LSMs. (Hepatology 2021;74:1496-1508. P rimary biliary cholangitis (PBC) is an autoimmune liver disease characterized by destructive cholangitis affecting the small intrahepatic