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We measured the μ + SR Knight shift in the hole-doped organic metal κ -(ET) 4 Hg 3 - δ Cl 8 , δ =22%, and re-analyzed temperature dependence of μ + SR Knight shift of the isostructural compound κ -(ET) 4 Hg 3 - δ Br 8 , δ =11%. The former underwent insulating and the latter has superconducting ground state. By lowering temperature the Knight shift gradually increased and was almost unchanged for κ -HgCl and κ -HgBr metals, respectively. We found a prominent deviation from linearity in the K (χ) plot of κ -HgCl below 100 K whereas the result of reanalysis of κ -HgBr shows there is almost no linearity of the K (χ) plot, although the absolute value of the μ + Knight shift K is comparable with that of κ -HgCl at low-temperature. The hyperfine coupling constant of κ -HgCl was estimated as A hf (κ -HgCl) = 282 Oe/ μ B . This value is comparable with our calculation assuming a point dipole between muon site, determined by the electronic potential calculation using density functional theory, and the localized spin at the Cl site. In consideration of both samples being in the vicinity of same quantum criticality, the muon Knight shift is more sensitive to the insulating sample with enhanced antiferromagnetic fluctuations. We discuss the relation between enhanced antiferromagnetic spin fluctuations, Non-Fermi liquidity, and superconductivity in these systems. [ABSTRACT FROM AUTHOR]

We present an exploration of the effect of electron-phonon coupling and broken inversion symmetry on the electronic and thermal properties of the semimetal LaRhGe3. Our transport measurements reveal evidence for electron-hole compensation at low temperatures, resulting in a large magnetoresistance of 3000% at 1.8 K and 14 T. The carrier concentration is on the order of 1021/cm3 with high carrier mobilities of 2000 cm2/Vs. When coupled to our theoretical demonstration of symmetry-protected almost movable Weyl nodal lines, we conclude that LaRhGe3 supports a Weyl semimetallic state. We discover superconductivity in this compound with a Tc of 0.39(1) K and Bc(0) of 2.2(1) mT, with evidence from specific heat and transverse-field muon spin relaxation. We find an exponential dependence in the normal state electrical resistivity below ~50 K, while Seebeck coefficient and thermal conductivity measurements each reveal a prominent peak at low temperatures, indicative of strong electron-phonon interactions. To this end, we examine the temperature-dependent Raman spectra of LaRhGe3 and find that the lifetime of the lowest energy A1 phonon is dominated by phonon-electron scattering instead of anharmonic decay. We conclude that LaRhGe3 has strong electron-phonon coupling in the normal state, while the superconductivity emerges from weak electron-phonon coupling. These results open up the investigation of electron-phonon interactions in the normal state of superconducting non-centrosymmetric Weyl semimetals. [ABSTRACT FROM AUTHOR]

What is Known and Objective: Carbapenem‐resistant Gram‐negative bacterial pathogens continue to threaten public health. Avibactam (AVI), a novel non‐β‐lactam β‐lactamase inhibitor, has been approved for use with ceftazidime (CAZ) mainly against carbapenem‐resistant Enterobacteriaceae. Therapeutic drug monitoring (TDM) is urgently needed to optimize dosage regimens to maximize efficacy, minimize toxicity, and delay the emergence of resistance. This study aims to develop and validate a rapid, simple, and economical LC–MS/MS method for simultaneous determination of CAZ/AVI in human plasma. Methods: Samples were processed by simple protein precipitation, and gradient elution strategy was applied to separate CAZ and AVI on a reverse‐phase C18 column; with subsequent detection by the mass spectrometer in a positive and negative ion switching mode. Plasma samples from patients were analysed. Results and Discussion: A 4‐min run of LC–MS/MS was developed. The precision, trueness, matrix effect, extraction recovery, carry‐over, dilution integrity, and stability were all acceptable for a bioanalytical method. The method was successfully applied to the determination of CAZ and AVI in patients, and a considerable PK variability of CAZ/AVI was observed among patients. What is New and Conclusion: A robust, rapid, simple, and economical LC–MS/MS method for the simultaneous determination of CAZ and AVI was developed. The considerable PK variability of CAZ/AVI among patients demonstrates the clinical significance of TDM. [ABSTRACT FROM AUTHOR]

Sirolimus (SRL) is commonly used in transplant patients to prevent organ transplant rejection. The current guidelines recommend to perform SRL therapeutic drug monitoring regularly to improve treatment outcomes and avoid adverse effects. Consequently, a precise and accurate method for determining SRL is crucial in clinical practice. Currently, liquid chromatography–tandem mass spectrometry (LC-MS/MS) and immunoassays have been widely adopted for determining SRL concentrations. However, previous studies have shown that immunoassays exhibit a positive bias compared to LC-MS/MS. As the new updated version of the EMIT-based Viva-E® System (SVPS), this study aims to compare SRL blood concentrations measured by the SVPS and LC-MS/MS. The residual whole-blood samples obtained from transplant patients were simultaneously analyzed using the SVPS and LC-MS/MS, respectively. The correlation between the two assays was analyzed using the linear regression analysis and Deming linear regression. The Pearson correlation coefficient and Intraclass correlation coefficient (ICC) analysis were executed. The Paired Wilcoxon test and Bland-Altman analysis were performed to assess the concordance between the two methods. The SVPS considerably increased SRL concentration value by 46.62 % as compared to the LC-MS/MS method. When SRL concentrations measured by the SVPS were above 4.0 ng/mL, there was no significant difference between the corrected SVPS concentrations after using the Deming linear regression equation, indicating their interchangeability. Given the significant disparities observed between EMIT and LC-MS/MS, it is crucial to indicate the methodology and instruments in both TDM reports and future clinical guidelines. Our study also provides the conversion formulas between the SVPS and LC-MS/MS, which can be applied as a reference for different clinical centers. • Sirolimus level measured by Viva-ProE® System and LC-MS/MS were first evaluated. • Viva-ProE® System increased level by 46.62 % on average vs LC-MS/MS. • Note methodological differences when interpreting TDM reports. • Future guidelines should indicate the methodology for sirolimus detection. • Conversion formulas can be used between two methods if value is above 4 ng/mL. [ABSTRACT FROM AUTHOR]

The identification result of operational mode is eurychoric while operational mode identification is investigated under ambient excitation, which is influenced by the signal size and the time interval. The operational mode identification method, which is based on the sliding time window method and the eigensystem realization algorithm (ERA), is investigated to improve the identification accuracy and stability. Firstly, the theory of the ERA method is introduced. Secondly, the strategy for decomposition and implementation is put forward, including the buliding time window method and the filtration method of modes. At last. an example is studied, where the model of a cantilever beam is built and the white noise exciting is input. Results show that the operational mode identification method can realize the modes, and has high robustness to the signal to noise ratio and signal size. [ABSTRACT FROM AUTHOR]

We report the discovery of a new fluoride-arsenide bulk diluted magnetic semiconductor (Ba,K)F(Zn,Mn)As with the tetragonal ZrCuSiAs-type structure which is identical to that of the '1111' iron-based superconductors. The joint hole doping via (Ba,K) substitution &spin doping via (Zn,Mn) substitution results in ferromagnetic order with Curie temperature up to 30 K and demonstrates that the ferromagnetic interactions between the localized spins are mediated by the carriers. Muon spin relaxation measurements confirm the intrinsic nature of the long range magnetic order in the entire volume in the ferromagnetic phase. This is the first time that a diluted magnetic semiconductor with decoupled spin and charge doping is achieved in a fluoride compound. Comparing to the isostructure oxide counterpart of LaOZnSb, the fluoride DMS (Ba,K)F(Zn,Mn)As shows much improved semiconductive behavior that would be benefit for further application developments. [ABSTRACT FROM AUTHOR]

Iron-chalcogenide superconductors FeSe 1- x S x possess unique electronic properties such as nonmagnetic nematic order and its quantum critical point. The nature of superconductivity with such nematicity is important for understanding the mechanism of unconventional superconductivity. A recent theory suggested the possible emergence of a fundamentally new class of superconductivity with the so-called Bogoliubov Fermi surfaces (BFSs) in this system. However, such an ultranodal pair state requires broken time-reversal symmetry (TRS) in the superconducting state, which has not been observed experimentally. Here, we report muon spin relaxation ( μ SR) measurements in FeSe 1- x S x superconductors for 0 ≤ x ≤ 0.22 covering both orthorhombic (nematic) and tetragonal phases. We find that the zero-field muon relaxation rate is enhanced below the superconducting transition temperature T c for all compositions, indicating that the superconducting state breaks TRS both in the nematic and tetragonal phases. Moreover, the transverse-field μ SR measurements reveal that the superfluid density shows an unexpected and substantial reduction in the tetragonal phase ( x > 0.17 ). This implies that a significant fraction of electrons remain unpaired in the zero-temperature limit, which cannot be explained by the known unconventional superconducting states with point or line nodes. The TRS breaking and the suppressed superfluid density in the tetragonal phase, together with the reported enhanced zero-energy excitations, are consistent with the ultranodal pair state with BFSs. The present results reveal two different superconducting states with broken TRS separated by the nematic critical point in FeSe 1- x S x , which calls for the theory of microscopic origins that account for the relation between nematicity and superconductivity.

Double perovskites (DP) of the general formula Ba 2 MReO 6 , where M = Mg, Zn, and Y 2/3 , all based on Re 6+ (5d 1 , t 2g 1 ), were synthesized and studied using magnetization, heat capacity, muon spin relaxation, and neutron-scattering techniques. All are cubic, Fm3̅m, at ambient temperature to within the resolution of the X-ray and neutron diffraction data, although the muon data suggest the possibility of a local distortion for M = Mg. The M = Mg DP is a ferromagnet, T c = 18 K, with a saturation moment ∼0.3 bohr magnetons at 3 K. There are two anomalies in the heat capacity: a sharp feature at 18 K and a broad maximum centered near 33 K. The total entropy loss below 45 K is 9.68 e.u., which approaches R ln 4 (11.52 e.u.) supporting a j = 3/2 ground state. The unit cell constants of Ba 2 MgReO 6 and the isostructural, isoelectronic analogue, Ba 2 LiOsO 6 , differ by only 0.1%, yet the latter is an anti-ferromagnet. The M = Zn DP also appears to be a ferromagnet, T c = 11 K, μ sat (Re) = 0.1 μ B . In this case the heat capacity shows a somewhat broad peak near 10 K and a broader maximum at ∼33 K, behavior that can be traced to a smaller particle size, ∼30 nm, for this sample. For both M = Mg and Zn, the low-temperature magnetic heat capacity follows a T 3/2 behavior, consistent with a ferromagnetic spin wave. An attempt to attribute the broad 33 K heat capacity anomalies to a splitting of the j = 3/2 state by a crystal distortion is not supported by inelastic neutron scattering, which shows no transition at the expected energy of ∼7 meV nor any transition up to 100 meV. However, the results for the two ferromagnets are compared to the theory of Chen, Pereira, and Balents, and the computed heat capacity predicts the two maxima observed experimentally. The M = Y 2/3 DP, with a significantly larger cell constant (3%) than the ferromagnets, shows predominantly anti-ferromagnetic correlations, and the ground state is complex with a spin frozen component T g = 16 K from both direct current and alternating current susceptibility and μSR data but with a persistent dynamic component. The low-temperature heat capacity shows a T 1 power law. The unit cell constant of B = Y 2/3 is less than 1% larger than that of the ferromagnetic Os 7+ (5d 1 ) DP, Ba 2 NaOsO 6 .