Heat transport study of the spin liquid candidate 1T-TaS2

We present the ultra-low-temperature thermal conductivity measurements on single crystals of the prototypical charge-density-wave material 1$T$-TaS$_2$, which was recently argued to be a candidate for quantum spin liquid. Our experiments show that the residual linear term of thermal conductivity at zero field is essentially zero, within the experimental accuracy. Furthermore, the thermal conductivity is found to be insensitive to the magnetic field up to 9 T. These results clearly demonstrate the absence of itinerant magnetic excitations with fermionic statistics in bulk 1$T$-TaS$_2$ and, thus, put a strong constraint on the theories of the ground state of this material.Comment: 5 pages, 3 figure

Magnetic anisotropy in van-der-Waals ferromagnet VI3

A comprehensive study of magnetocrystalline anisotropy of a layered van-der-Waals ferromagnet VI3 was performed. We measured angular dependences of the torque and magnetization with respect to the direction of the applied magnetic field within the "ac" plane perpendicular to and within the basal ab plane, respectively. A two-fold butterfly-like signal was detected by magnetization in the perpendicular "ac" plane. This signal symmetry remains conserved throughout all magnetic regimes as well as through the known structural transition down to the lowest temperatures. The maximum of the magnetization signal and the resulting magnetization easy axis is significantly tilted from the principal c axis by ~40{\deg}. The close relation of the magnetocrystalline anisotropy to the crystal structure was documented. In contrast, a two-fold-like angular signal was detected in the paramagnetic region within the ab plane in the monoclinic phase, which transforms into a six-fold-like signal below the Curie temperature TC. With further cooling, another six-fold-like signal with an angular shift of ~30{\deg} grows approaching TFM. Below TFM, in the triclinic phase, the original six-fold-like signal vanishes, being replaced by a secondary six-fold-like signal with an angular shift of ~30{\deg}.Comment: 14 pages, 10 figure

Dysregulation of epicardial adipose tissue in cachexia due to heart failure. the role of natriuretic peptides and cardiolipin

Background: Cachexia worsens long-term prognosis of patients with heart failure (HF). Effective treatment of cachexia is missing. We seek to characterize mechanisms of cachexia in adipose tissue, which could serve as novel targets for the treatment. Methods: The study was conducted in advanced HF patients (n = 52; 83% male patients) undergoing heart transplantation. Patients with ≥7.5% non-intentional body weight (BW) loss during the last 6 months were rated cachectic. Clinical characteristics and circulating markers were compared between cachectic (n = 17) and the remaining, BW-stable patients. In epicardial adipose tissue (EAT), expression of selected genes was evaluated, and a combined metabolomic/lipidomic analysis was performed to assess (i) the role of adipose tissue metabolism in the development of cachexia and (ii) potential impact of cachexia-associated changes on EAT-myocardium environment. Results: Cachectic vs. BW-stable patients had higher plasma levels of natriuretic peptide B (BNP; 2007 ± 1229 vs. 1411 ± 1272 pg/mL; P = 0.010) and lower EAT thickness (2.1 ± 0.8 vs. 2.9 ± 1.4 mm; P = 0.010), and they were treated with ~2.5-fold lower dose of both β-blockers and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACE/ARB-inhibitors). The overall pattern of EAT gene expression suggested simultaneous activation of lipolysis and lipogenesis in cachexia. Lower ratio between expression levels of natriuretic peptide receptors C and A was observed in cachectic vs. BW-stable patients (0.47 vs. 1.30), supporting activation of EAT lipolysis by natriuretic peptides. Fundamental differences in metabolome/lipidome between BW-stable and cachectic patients were found. Mitochondrial phospholipid cardiolipin (CL), specifically the least abundant CL 70:6 species (containing C16:1, C18:1, and C18:2 acyls), was the most discriminating analyte (partial least squares discriminant analysis; variable importance in projection score = 4). Its EAT levels were higher in cachectic as compared with BW-stable patients and correlated with the degree of BW loss during the last 6 months (r = −0.94; P = 0.036). Conclusions: Our results suggest that (i) BNP signalling contributes to changes in EAT metabolism in cardiac cachexia and (ii) maintenance of stable BW and ‘healthy’ EAT-myocardium microenvironment depends on the ability to tolerate higher doses of both ACE/ARB inhibitors and β-adrenergic blockers. In line with preclinical studies, we show for the first time in humans the association of cachexia with increased adipose tissue levels of CL. Specifically, CL 70:6 could precipitate wasting of adipose tissue, and thus, it could represent a therapeutic target to ameliorate cachexia

Properties of spin 1/2 triangular lattice antiferromagnets: CuRE2Ge2O8 (RE=Y, La)

We found new two-dimensional (2D) quantum (S=1/2) antiferromagnetic systems: CuRE2Ge2O8 (RE=Y and La). According to our analysis of high-resolution X-ray and neutron diffraction experiments, the Cu-network of CuRE2Ge2O8 (RE=Y and La) exhibits a 2D triangular lattice linked via weak bonds along the perpendicular b-axis. Our bulk characterizations from 0.08 to 400 K show that they undergo a long-range order at 0.51(1) and 1.09(4) K for the Y and La systems, respectively. Interestingly, they also exhibit field induced phase transitions. For theoretical understanding, we carried out the density functional theory (DFT) band calculations to find that they are typical charge-transfer-type insulators with a gap of Eg = 2 eV. Taken together, our observations make CuRE2Ge2O8 (RE=Y and La) additional examples of low-dimensional quantum spin triangular antiferromagnets with the low-temperature magnetic ordering.Comment: 15 pages, 6 figures, and 1 tabl

Magnetic properties of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskite structure

Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskites were synthesized by pyrolysis of glycerol-salt mixtures and their magnetic properties were investigated. X-ray diffraction was employed to refine crystal structures of these perovskite materials and set sample purity degree. The magnetic ground state of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) has been characterized using magnetic susceptibility measurements. They indicate that Sr2Ni0.75Mg0.25MoO6 is ordered in an antiferromagnetic state below 56 K while Sr2Ni0.5Mg0.5MoO6 is paramagnetic. © Published under licence by IOP Publishing Ltd.3.6121.2017/8.9A03.21.0006, 02.The work was supported by MES of RF (contract No. 3.6121.2017/8.9), and by Act 211 Government of RF (contract No. 02.A03.21.0006), and supported in part y FASO of Russia (theme “Flux” No. AAA-A18-118020190112-8)

The clinical, biochemical and genetic features associated with RMND1-related mitochondrial disease

Background Mutations in the RMND1 (Required for Meiotic Nuclear Division protein 1) gene have recently been linked to infantile onset mitochondrial disease characterised by multiple mitochondrial respiratory chain defects. Methods We summarised the clinical, biochemical and molecular genetic investigation of an international cohort of affected individuals with RMND1 mutations. In addition, we reviewed all the previously published cases to determine the genotype–phenotype correlates and performed survival analysis to identify prognostic factors. Results We identified 14 new cases from 11 pedigrees that harbour recessive RMND1 mutations, including 6 novel variants: c.533C>A, p.(Thr178Lys); c.565C>T, p.(Gln189*); c.631G>A, p.(Val211Met); c.1303C>T, p.(Leu435Phe); c.830+1G>A and c.1317+1G>T. Together with all previously published cases (n=32), we show that congenital sensorineural deafness, hypotonia, developmental delay and lactic acidaemia are common clinical manifestations with disease onset under 2 years. Renal involvement is more prevalent than seizures (66% vs 44%). In addition, median survival time was longer in patients with renal involvement compared with those without renal disease (6 years vs 8 months, p=0.009). The neurological phenotype also appears milder in patients with renal involvement. Conclusions The clinical phenotypes and prognosis associated with RMND1 mutations are more heterogeneous than that were initially described. Regular monitoring of kidney function is imperative in the clinical practice in light of nephropathy being present in over 60% of cases. Furthermore, renal replacement therapy should be considered particularly in those patients with mild neurological manifestation as shown in our study that four recipients of kidney transplant demonstrate good clinical outcome to date

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.

OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)