We show that the symmetry of the spin zigzag chain $E$ phase of the orthorhombic perovskite manganites and nickelates allows for the existence of a finite ferroelectric polarization. The proposed microscopic mechanism is independent of spin-orbit coupling. We predict that the polarization induced by the $E$-type magnetic order can potentially be enhanced by up to 2 orders of magnitude with respect to that in the spiral magnetic phases of ${\mathrm{TbMnO}}_3$ and similar multiferroic compounds.

Using first-principles calculations, we study the microscopic origin of ferroelectricity (FE) induced by magnetic order in the orthorhombic ${\mathrm{HoMnO}}_3$. We obtain the largest ferroelectric polarization observed in the whole class of improper magnetic ferroelectrics to date. We find that the two proposed mechanisms for FE in multiferroics, lattice and electronic based, are simultaneously active in this compound: a large portion of the ferroelectric polarization arises due to quantum-mechanical effects of electron orbital polarization, in addition to the conventional polar atomic displacements. An interesting mechanism for switching the magnetoelectric domains by an electric field via a 180° coherent rotation of Mn spins is also proposed.

A class of materials known as “ferroelectric metals” was discussed theoretically by Anderson and Blount in 1965 [ Phys. Rev. Lett. 14, 217 (1965)], but to date no examples of this class of materials have been reported. Here we present measurements of the elastic moduli of ${\mathrm{C}\mathrm{d}}_2{\mathrm{R}\mathrm{e}}_2{\mathrm{O}}_7$ through the 200 K cubic-to-tetragonal phase transition. A Landau analysis of the moduli reveals that the transition is consistent with ${\mathrm{C}\mathrm{d}}_2{\mathrm{R}\mathrm{e}}_2{\mathrm{O}}_7$ being classified as a ferroelectric metal in the weaker sense described by Anderson and Blount (loss of a center of symmetry). First-principles calculations of the lattice instabilities indicate that the dominant lattice instability corresponds to a twofold degenerate mode with $E_u$ symmetry and that motions of the O ions forming the O octahedra dominate the energetics of the transition.

We have measured the polarized Raman scattering spectra of ${\mathrm{Cd}}_2{\mathrm{Re}}_2{\mathrm{O}}_7$, the first superconducting pyrochlore, as a function of temperature. For temperatures below the cubic-to-tetragonal structural phase transition (SPT) at 200 K, a peak with $B_1$ symmetry develops at zero frequency with divergent intensity. We identify this peak as the first observation of the Goldstone phonon in a crystalline solid. The Goldstone phonon is a collective excitation that exists due to the breaking of the continuous symmetry with the SPT. Its emergence coincides with that of a Raman-active soft mode. The order parameter for both features derives from an unstable doubly degenerate vibration (with $E_u$ symmetry) of the O1 atoms which drives the SPT.

The high prevalence of persistent dyslipidemia in primary and specialized care patients treated with statins justifies the need to identify its reasons and develop the recommendations on the treatment optimization. At present, Russian studies focusing on the achievement of target lipid levels remain scarce, which emphasizes the importance of the problem and its further investigation.Aim.Cross-sectional epidemiological study which assessed the prevalence of persistent dyslipidemia in statin-treated patients and analysed the predictors of the achievement of target lipid levels.Material and methods.The lipid profile parameters were analysed in 1586 statin-treated out-patients with varied levels of cardiovascular risk, taking into account the type of lipid-lowering therapy and its doses. The assessment of the cardiovascular event (CVE) risk and the definition of target levels of low-density lipoprotein cholesterol (LDL–CH), as well as normal levels of triglycerides (TG) and high-density lipoprotein cholesterol (HDL–CH), was based on the clinical recommendations by the European Society of Cardiology (ESC 2007) and by the European Society of Cardiology and the European Atherosclerosis Society (ESC/EAS 2011).Results.The analysis based on the ESC 2007 recommendations has demonstrated that the target levels of LDL–CH (<2,5 mmol/l for high-risk patients) were not achieved in 53,5% of the participants. The elevation of LDL–CH levels could be isolated or combined with the HDL–CH decrease and/or the TG increase. Low levels of HDL–CH were observed in 32,3% of the patients, while high TG levels were registered in 55,6% of the participants. The achievement of target LDL–CH levels was predicted by the higher-dose statin therapy (odds ratio 0,44). The analysis based on the ESC/EAS 2011 recommendations has shown that the prevalence of target LDL–CH levels was 12,2% in very high-risk patients (<1,8 mmol/l), 30,3% in high-risk patients (<2,5 mmol/l), and 53,4% in moderate-risk patients (<3,0 mol/l).Conclusion.Over a half of the statin-treated patients failed to achieve target levels of LDL–CH. The lowest prevalence of target LDL–CH levels was observed in very high-risk and high-risk patients. The predictors of target LDL–CH level achievement included moderate cardiovascular risk and higher-dose statin therapy. The obtained results suggest that the correction of persistent dyslipidemia in statin-treated patients could be achieved via increasing the satin dose and combining lipid-lowering medications.

Subclinical atherosclerosis is an initial, latent stage of chronic progressing arterial inflammation. Destabilisation of asymptomatic, hemodynamically non-significant atherosclerotic plaques (AP) could lead to myocardial infarction, stroke, or sudden death. Since the assessment of AP stability is problematic in real-world clinical settings, the risk stratification should, at least, account for the presence of subclinical atherosclerosis. In 600 ambulatory patients from the Moscow City Western Administrative Okrug who had low and moderate SCORE-assessed cardiovascular risk levels, the prevalence of AP, based on the duplex carotid ultrasound results, was 59% (n=358). Presently, no standard guidelines exist on cardiovascular risk stratification which would include the assessment of subclinical atherosclerosis, despite the importance of the latter as a prognostic factor. Large clinical studies on prognosis in patients with subclinical atherosclerosis will clarify the role of this parameter as an independent cardiovascular risk factor and facilitate the development of respective clinical recommendations.