Phase transitions and slow spin dynamics of slightly inverted A-site spinel CoAl2-xGaxO4.

We report the properties of an A-site spinel magnet, CoAl2-xGaxO4, and analyze its anomalous, low-temperature magnetic behavior, which is derived from inherent, magnetically frustrated interactions. Rietveld analysis of the x-ray diffraction profile for CoAl2-xGaxO4revealed that the metallic ions were randomly distributed in the tetrahedral (A-) and octahedral (B-) sites in the cubic spinel structure. The inversion parameterηcould be controlled by varying the gallium (Ga) composition in the range 0.055 ⩽η⩽ 0.664. The composition-induced Néel-to-spin-glass (NSG) transition occurred between 0.05 ⩽η⩽ 0.08 and was verified by measurements of DC-AC susceptibilitiesχand thermoremanent magnetization (TRM) below the Néel transition temperatureTN. The relaxation rate and derivative with respect to temperature of TRM increased at bothTNand the spin glass (SG) transition temperatureTSG. The TRM decayed rapidly above and below these transitions. TRM was highly sensitive to macroscopic magnetic transitions that occurred in both the Néel and SG phases of CoAl2-xGaxO4. In the vicinity of the NSG boundary, there was a maximum of the TRM relaxation rate atTmax

Age-related declines in α-Klotho drive progenitor cell mitochondrial dysfunction and impaired muscle regeneration.

While young muscle is capable of restoring the original architecture of damaged myofibers, aged muscle displays a markedly reduced regeneration. We show that expression of the "anti-aging" protein, α-Klotho, is up-regulated within young injured muscle as a result of transient Klotho promoter demethylation. However, epigenetic control of the Klotho promoter is lost with aging. Genetic inhibition of α-Klotho in vivo disrupted muscle progenitor cell (MPC) lineage progression and impaired myofiber regeneration, revealing a critical role for α-Klotho in the regenerative cascade. Genetic silencing of Klotho in young MPCs drove mitochondrial DNA (mtDNA) damage and decreased cellular bioenergetics. Conversely, supplementation with α-Klotho restored mtDNA integrity and bioenergetics of aged MPCs to youthful levels in vitro and enhanced functional regeneration of aged muscle in vivo in a temporally-dependent manner. These studies identify a role for α-Klotho in the regulation of MPC mitochondrial function and implicate α-Klotho declines as a driver of impaired muscle regeneration with age.

Cost-effectiveness of palbociclib in hormone receptor-positive advanced breast cancer.

BACKGROUND: Palbociclib (PAL), a novel small-molecule inhibitor of cyclin-dependent kinases 4 and 6 for the treatment of advanced breast cancer, has demonstrated significant efficacy in prolonging progression-free survival when added to existing therapies. Considering the high cost of PAL, we assessed cost-effectiveness of adding PAL to usual care in treatment of advanced breast cancer. METHODS: We developed a discrete event simulation model to simulate time to cancer progression and to compare life time clinical benefit and cost of alternative treatment strategies for patients with metastatic disease from societal perspective. Per approved indication, endocrine treatment naive patients were assigned to PAL plus letrozole (PAL + LET) or letrozole alone (LET). Patients with prior endocrine therapy were assigned to PAL plus fulvestrant (FUL) (PAL + FUL) or FUL alone. The model assumptions were informed based on published clinical trial data and other peer reviewed studies. We carried out one-way and probabilistic sensitivity analyses to assess the robustness of our results to the changes in model assumptions. RESULTS: In treatment-naive patients, the addition of PAL to LET cost an estimated $768 498 per additional quality-adjusted life-year (QALY) gained. The addition of PAL to FUL in patients with prior endocrine therapy cost an estimated $918 166 per QALY gained. Sensitivity analyses demonstrated adding PAL has a 0% chance of being cost-effectiveness in either patient groups at a willingness-to-pay threshold of $100 000 per QALY. CONCLUSION: From a societal perspective, PAL treatment of both patient groups (with and without prior endocrine therapy) is highly unlikely to be cost-effective compared with the usual care in the USA.

Magnetic relaxations of antiferromagnetic nanoparticles in magnetic fields.

We reexamine anomalous magnetic relaxations of ferritin in magnetic fields, the presence of which has been regarded as evidence suggesting the existence of thermally assisted macroscopic quantum tunneling in antiferromagnetic nanoparticles. In the present study, relaxation curves of ferritin are examined using an approach that is free from assumptions regarding distributions of various parameters of polydispersive particles. The results are not anomalous. In other words, the relaxation is accelerated by the field, as expected for classical superparamagnetic fluctuations.

Phase transitions of iron-nitride magnetic fluids.

Phase transitions of magnetic fluids in the zero field were studied from the viewpoint of static susceptibility and typical relaxation time in order to distinguish between the transitions and the blocking phenomena. We used iron-nitride magnetic fluids containing nearly uniform particles so as to remove the effects of particle-size distribution. In the densest sample, we observed the growth of ferromagnetic fluctuations and, in the diluted samples, a temperature-induced first-order phase transition.

Pain following intravenous administration of sedative agents: a comparison of propofol with three benzodiazepines.

The purpose of the present study is to compare the injection pain of propofol with that of benzodiazepines when used for intravenous sedation. In addition, we evaluated the efficacy of coadministering a small dose of 1% lidocaine (20 mg) to reduce the pain accompanying propofol injection. Intravenous propofol, diazepam, midazolam, or flunitrazepam were administered on separate occasions to volunteers and outpatients. The degree of injection pain was evaluated by the Visual Analog Scale (VAS) ruler. The efficacy of premixed lidocaine with propofol was also compared among the patients. The venous pain of propofol was significantly more intense than that of the three other drugs (P < 0.05). The injection pain of diazepam was more intense than that of midazolam (P < 0.05). Many patients reported no pain when propofol was coadministered with lidocaine. The addition of a small dose (20 mg) of lidocaine reduced the VAS pain score to comparable levels observed for benzodiazepines. Because injection pain might affect the patients' comfort during sedation, the addition of lidocaine to the propofol injection is deemed useful for intravenous sedation.

Effects of block analgesia on attenuating intraoperative stress responses during oral surgery.

Surgical intervention affects cardiorespiratory function and deteriorates the homeostatic mechanisms. The aim of this study was to evaluate the effect of block analgesia, which may minimize the intraoperative stress responses during oral surgery. In addition, we evaluated whether block analgesia could lessen the anesthetic requirements. Twenty-eight operative patients were randomly allocated to one of four groups: group 1, 1.3MAC without block analgesia; group 2, 1.6MAC without block analgesia; group 3, 1.0MAC with block analgesia; and group 4, 1.3MAC with block analgesia. Systolic blood pressure (SBP), heart rate (HR), and plasma norepinephrine levels (NE) were measured and compared. Results showed that the increases in SBP, HR, and NE in groups 1 and 2 were greater than those in groups 3 and 4. SBP elevation in group 1 was the greatest among all groups. These results suggest that block analgesia appears to be effective for preventing hyperreactivity of the sympathetic nervous and endocrine systems. In conclusion, general anesthesia combined with block analgesia assures safer anesthesia for patients with cardiovascular diseases or elderly patients who require cardiovascular stability during surgery.