Coherent spin-wave transport in an antiferromagnet.

Magnonics is a research field complementary to spintronics, in which quanta of spin waves (magnons) replace electrons as information carriers, promising lower dissipation1-3. The development of ultrafast nanoscale magnonic logic circuits calls for new tools and materials to generate coherent spin waves with frequencies as high, and wavelengths as short, as possible4,5. Antiferromagnets can host spin waves at terahertz (THz) frequencies and are therefore seen as a future platform for the fastest and the least dissipative transfer of information6-11. However, the generation of short-wavelength coherent propagating magnons in antiferromagnets has so far remained elusive. Here we report the efficient emission and detection of a nanometer-scale wavepacket of coherent propagating magnons in antiferromagnetic DyFeO3 using ultrashort pulses of light. The subwavelength confinement of the laser field due to large absorption creates a strongly non-uniform spin excitation profile, enabling the propagation of a broadband continuum of coherent THz spin waves. The wavepacket contains magnons with a shortest detected wavelength of 125 nm that propagate with supersonic velocities of more than 13 km/s into the material. This source of coherent short-wavelength spin carriers opens up new prospects for THz antiferromagnetic magnonics and coherence-mediated logic devices at THz frequencies.

Transcatheter Implantable Devices to Monitoring of Elevated Left Atrial Pressures in Patients with Chronic Heart Failure.

Elevated left atrial (LA) pressures are associated with poor prognosis in heart failure (HF). Invasive monitoring of LA-pressures and direct mechanical LA-decompression are associated with functional improvement in patients suffering from HF both with reduced and preserved ejection fraction. We aim to review the current available percutaneously implantable sensors for haemodynamic telemonitoring of LA-pressures (direct LAP sensor device-HeartPOD; right ventricular device-Chronicle; pulmonary artery device-CardioMEMs).

Spin Pumping and Measurement of Spin Currents in Optical Superlattices.

We report on the experimental implementation of a spin pump with ultracold bosonic atoms in an optical superlattice. In the limit of isolated double wells, it represents a 1D dynamical version of the quantum spin Hall effect. Starting from an antiferromagnetically ordered spin chain, we periodically vary the underlying spin-dependent Hamiltonian and observe a spin current without charge transport. We demonstrate a novel detection method to measure spin currents in optical lattices via superexchange oscillations emerging after a projection onto static double wells. Furthermore, we directly verify spin transport through in situ measurements of the spins' center-of-mass displacement.

A novel miR-371a-5p-mediated pathway, leading to BAG3 upregulation in cardiomyocytes in response to epinephrine, is lost in Takotsubo cardiomyopathy.

Molecular mechanisms protecting cardiomyocytes from stress-induced death, including tension stress, are essential for cardiac physiology and defects in these protective mechanisms can result in pathological alterations. Bcl2-associated athanogene 3 (BAG3) is expressed in cardiomyocytes and is a component of the chaperone-assisted autophagy pathway, essential for homeostasis of mechanically altered cells. BAG3 ablation in mice results in a lethal cardiomyopathy soon after birth and mutations of this gene have been associated with different cardiomyopathies including stress-induced Takotsubo cardiomyopathy (TTC). The pathogenic mechanism leading to TTC has not been defined, but it has been suggested that the heart can be damaged by excessive epinephrine (epi) spillover in the absence of a protective mechanism. The aim of this study was to provide more evidence for a role of BAG3 in the pathogenesis of TTC. Therefore, we sequenced BAG3 gene in 70 TTC patients and in 81 healthy donors with the absence of evaluable cardiovascular disease. Mutations and polymorphisms detected in the BAG3 gene included a frequent nucleotide change g2252c in the BAG3 3'-untranslated region (3'-UTR) of Takotsubo patients (P<0.05), resulting in loss of binding of microRNA-371a-5p (miR-371a-5p) as evidenced by dual-luciferase reporter assays and argonaute RNA-induced silencing complex catalytic component 2/pull-down assays. Moreover, we describe a novel signaling pathway in cardiomyocytes that leads to BAG3 upregulation on exposure to epi through an ERK-dependent upregulation of miR-371a-5p. In conclusion, the presence of a g2252c polymorphism in the BAG3 3'-UTR determines loss of miR-371a-5p binding and results in an altered response to epi, potentially representing a new molecular mechanism that contributes to TTC pathogenesis.

Noise-assisted charge pump in elastically deformable molecular junctions.

We study a charge pump realized with an elastically deformable quantum dot whose center of mass follows a nonlinear stochastic dynamics. The interplay of noise, nonlinear effects, dissipation and interaction with an external time-dependent driving on the pumped charge is fully analyzed. The results show that the quantum pumping mechanism not only is not destroyed by the force fluctuations, but it becomes stronger when the forcing signal frequency is tuned close to the resonance of the vibrational mode. The robustness of the quantum pump with temperature is also investigated and an exponential decay of the pumped charge is found when the coupling to the vibrational mode is present. Implications of our results for nanoelectromechanical systems are also discussed.

Cooper pairs spintronics in triplet spin valves.

We study a spin valve with a triplet superconductor spacer intercalated between two ferromagnets with noncollinear magnetizations. We show that the magnetoresistance of the triplet spin valve depends on the relative orientations of the d vector, characterizing the superconducting order parameter, and the magnetization directions of the ferromagnetic layers. For devices characterized by a long superconductor, the effects of a polarized current sustained by Cooper pairs only are observed. In this regime, a supermagnetoresistance effect emerges, and the chiral symmetry of the order parameter of the superconducting spacer is easily recognized. Our findings open new perspectives in designing spintronics devices based on the cooperation of ferromagnetic and triplet correlations.

Controlling Luttinger liquid physics in spin ladders under a magnetic field.

We present a 14N nuclear magnetic resonance study of a single crystal of CuBr4(C5H12N)2 (BPCB) consisting of weakly coupled spin-1/2 Heisenberg antiferromagnetic ladders. Treating ladders in the gapless phase as Luttinger liquids, we are able to fully account for (i) the magnetic field dependence of the nuclear spin-lattice relaxation rate T1(-1) at 250 mK and for (ii) the phase transition to a 3D ordered phase occurring below 110 mK due to weak interladder exchange coupling. BPCB is thus an excellent model system where the possibility to control Luttinger liquid parameters in a continuous manner is demonstrated and the Luttinger liquid model tested in detail over the whole fermion band.

Acute aortic dissection in the young: clinical series.

Acute aortic dissection (AAD) is an uncommon lethal cardiovascular emergency demanding prompt diagnosis and aggressive therapeutic intervention. Although it usually affects males over 60 years of age, it may also occur in young adults with specific risk factors such as Marfan syndrome, bicuspid aortic valve and larger aortic dimensions. Moreover, it should be underlined that it is frequently associated with unusual presentation and that the mortality risk is similar to older AAD patients. Thus ''a call to arms'' of the medical community is needed to better understand the spectrum of acute aortic syndromes and to define appropriate diagnostic and therapeutic pathways. We report a series of 6 young patients with type A - AAD referred over the past years at our institute.

Atom-molecule coherence in a one-dimensional system.

We study a model of one-dimensional fermionic atoms with a narrow Feshbach resonance that allows them to bind in pairs to form bosonic molecules. We show that at low energy, a coherence develops between the molecule and fermion Luttinger liquids. At the same time, a gap opens in the spin excitation spectrum. The coherence implies that the order parameters for the molecular Bose-Einstein condensation and the atomic BCS pairing become identical. Moreover, both bosonic and fermionic charge density wave correlations decay exponentially, in contrast with a usual Luttinger liquid. We exhibit a Luther-Emery point where the systems can be described in terms of noninteracting pseudofermions. At this point we discuss the threshold behavior of density-density response functions.

Modeling and evaluation of continuity of care in a staff model HMO.

The concept of continuity in medicine refers to the delivery of care in an uninterrupted and coordinated manner and in accordance with the patient's medical needs. Many diseases and symptoms require serial observation and treatment over long periods and are interwoven with the patient's personal and social circumstances. We believe that the depth of a primary care provider's understanding of a patient is directly proportional to the total length of interaction between the patient and provider. We have reviewed the published studies in this area, and modeled continuity of care in an HMO clinic. The patients' ages, their visiting patterns, and the length of their interactions with their doctors were synthesized stochastically. We now propose a new way of defining continuity of care, the Fundamental Continuity of Care Index (FCCI), and recommend its use. Hospitals, insurance companies, and governments should be aware of the benefits of continuity and all physicians should commit themselves to longitudinal care for their patients.

A fundamental metric for continuity of care: modeling and performance evaluation.

The concept of continuity in medicine is fundamental and it refers to the delivery of medical care to a patient by a care provider in an uninterrupted and coordinated manner and in accordance with the medical care needs of the patient. Principal limitations of previous studies include the following. First, there is the absence of a deliberate effort to schedule a patient's successive visits with the same provider. Second, in most cases, the reported measures are derived from the data collected through questionnaires that patients and doctors are asked to complete from memory. This introduces an unreliability factor. Third, the reported continuity-related measures are restricted to the available patient sample and, as a result, they do not necessarily reflect a representative patient distribution by age in a typical community. Fourth, the relationship between the patient-doctor interaction interval and the continuity of medical care has never been explored systematically in the literature. This paper models continuity for a representative staff model health maintenance organization (HMO) clinic in suburban Arizona and simulates patient visits that are stochastically generated through utilizing representative numbers of patient visits and care providers. It focuses on individual-based continuity delivered by a primary care provider, i.e., a general practitioner. In the simulation, the visit patterns of patients, their ages, and the length of the interaction episodes are synthesized stochastically. The distributions reflect both the patient visit profile, by age, inherent in the 90,000+ patient electronic records collected at the CIGNA HMO clinic at Chandler, AZ, over a three-year period, and the population distribution inherent in the CIGNA records. A key characteristic of the model is that it aims at deliberately maximizing continuity by making a strong effort to schedule both a patient's regular visit and follow-ups with the primary care provider, subject to the provider's availability and schedule. This paper proposes a new definition of continuity, fundamental continuity of care index (FCCI), and argues that, fundamentally, a primary care provider's depth of understanding of the patient is directly proportional to the total length of interaction between the patient and the primary care provider. Utilizing the CIGNA summary data, this paper organizes patients into five age groups: 0-5 years, 5-15 years, 15-45 years, 45-60 years, and 60+ and synthesizes the corresponding arrival distributions. Performance results, obtained for a total of 55,056 patient visits over a three-year period indicate that, while 94-97% of the patient visits are with the primary care provider, patients spend 76-77% of the nominal total visit time with their primary care provider, leading to FCCI values ranging from 0.72 to 0.75. Performance results indicate that for different choices of the mean of the patient-doctor interaction duration, the average FCCI values, obtained following simulation, reveal an approximate bell-shaped graph. For values of the mean ranging from 5 to 10, 15, 20, 25, 35, 45, and 55 min, the average FCCI measure starts at 0.49, increases to a maximum of 0.88 corresponding to a mean of 25 min, and then decreases to 0.60. Thus, for a medical clinic, constrained by the number of care providers servicing a fixed number of patients, for a given population distribution by age, an optimum value for the average patient-doctor interaction duration may be obtained empirically that yields the maximal continuity measure.

[Mitral prolapse and the ergometric findings]. / Prolasso della mitrale e rilievi ergometrici.

In evaluating the significance of arrhythmias and ECG changes during exercise, 42 consecutive patients (pts) with mitral valve prolapse (MVP) underwent a symptom-limited cycloergometer Exercise Stress Test (EST) with load increase of 25 watts every 3 minutes. Eight patients (19%) were positive for anamnestic cardiopalm. The patients were divided in 2 groups, according to echocardiographic evidence of the MPV: group A (12 patients, mean age 32 +/- 13) with prolapse of one mitral leaflet and group B (30 patients, mean age 30 +/- 13) with prolapse of both mitral leaflets. Exercise duration doesn't differ significantly in the two groups. No arrhythmias during EST were found in group A, while arrhythmias were present in 6 patients (20%) in group B. A strong correlation was found between anamnestic cardiopalm and arrhythmias during EST (6/8 = 75%). Three of four patients (75%) with ST impairment during EST, showed at thallium myocardial scintigraphy a non reversible perfusion defect after exercise. These data showed a higher incidence of arrhythmias during EST in patients with MVP of both leaflets and good relationship with symptomatology of cardiopalm.

[Systemic effects of intravenous dipyridamole in patients of various age groups]. / Effetti sistemici del dipiridamolo endovena in soggetti di diverse classi di età.

Aim of this study was to assess the role of age-related vascular response in the onset of i.v. dipyridamole effects. The results of 129 patients who underwent a dipyridamole infusion were reviewed. The patients were divided into three according to age: 47 patients of less than 50 years (group I), 54 patients aged between 50 and 60 years (group II) and 28 patients of more than 60 years (group III). For each group heart frequency (HF) and systolic blood pressure (SBP) were considered in basal conditions, at the end of infusion and at the minimum value of SBP (SBP min); moreover the time in reaching SBP min was considered (time to SBP min). At the end of the infusion no significant changes in SBP were observed in all groups while the SBP min value reached from group III were significantly lower than basal (142.6 +/- 20.4 mmHg, p less than 0.02). The HF, without significant differences among the three groups in basal conditions, increased significantly at the end of infusion only in group I and II, with a more significant increase in group I at the time of SBP min with respect to groups II and III. The group 3 showed moreover, a significant longer time to SBP min (286 +/- 208 sec) respect to the group I and II (145 +/- 130 and 160 +/- 177 sec respectively) (p less than 0.02). From these data it can resume that age could be a factor to determine hemodynamic response to intravenous dipyridamole.