Terahertz electric-field-driven dynamical multiferroicity in SrTiO3.

The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention1-6. The theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization due to time-dependent electric polarization in non-ferromagnetic materials7,8. In simple terms, the coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. Here we provide experimental evidence of room-temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. We resonantly drive the infrared-active soft phonon mode with an intense circularly polarized terahertz electric field and detect the time-resolved magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab initio calculations using self-consistent phonon theory at a finite temperature9, reproduces qualitatively our experimental observations. A quantitatively correct magnitude was obtained for the effect by also considering the phonon analogue of the reciprocal of the Einstein-de Haas effect, which is also called the Barnett effect, in which the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for the control of magnetism, for example, for ultrafast magnetic switches, by coherently controlling the lattice vibrations with light.

Ultrafast Amplification and Nonlinear Magnetoelastic Coupling of Coherent Magnon Modes in an Antiferromagnet.

We investigate the role of domain walls in the ultrafast magnon dynamics of an antiferromagnetic NiO single crystal in a pump-probe experiment with variable pump photon energy. Analyzing the amplitude of the energy-dependent photoinduced ultrafast spin dynamics, we detect a yet unreported coupling between the material's characteristic terahertz- and gigahertz-magnon modes. We explain this unexpected coupling between two orthogonal eigenstates of the corresponding Hamiltonian by modeling the magnetoelastic interaction between spins in different domains. We find that such interaction, in the nonlinear regime, couples the two different magnon modes via the domain walls and it can be optically exploited via the exciton-magnon resonance.

Haplotypes of the genes (GCK and G6PC2) underlying the glucose/glucose-6-phosphate cycle are associated with pancreatic beta cell glucose sensitivity in patients with newly diagnosed type 2 diabetes from the VNDS study (VNDS 11).

BACKGROUND: Elevated fasting plasma glucose has been associated with increased risk for development of type 2 diabetes (T2D). The balance between glucokinase (GCK) and glucose-6-phosphate catalytic subunit 2 (G6PC2) activity are involved in glucose homeostasis through glycolytic flux, and subsequent insulin secretion. AIM: In this study, we evaluated the association between the genetic variability of G6PC2 and GCK genes and T2D-related quantitative traits. METHODS: In 794 drug-naïve, GADA-negative, newly diagnosed T2D patients (VNDS; NTC01526720) we performed: genotyping of 6 independent tag-SNPs within GCK gene and 5 tag-SNPs within G6PC2 gene; euglycaemic insulin clamp to assess insulin sensitivity; OGTT to estimate beta-cell function (derivative and proportional control; DC, PC) by mathematical modeling. Genetic association analysis has been conducted using Plink software. RESULTS: Two SNPs within GCK gene (rs882019 and rs1303722) were associated to DC in opposite way (both p < 0.004). Two G6PC2 variants (rs13387347 and rs560887) were associated to both parameters of insulin secretion (DC and PC) and to fasting C-peptide levels (all p < 0.038). Moreover, subjects carrying the A allele of rs560887 showed higher values of 2h-plasma glucose (2hPG) (p = 0.033). Haplotype analysis revealed that GCK (AACAAA) haplotype was associated to decreased fasting C-peptide levels, whereas, the most frequent haplotype of G6PC2 (GGAAG) was associated with higher fasting C-peptide levels (p = 0.001), higher PC (ß = 6.87, p = 0.022) and the lower 2hPG (p = 0.012). CONCLUSION: Our findings confirmed the role of GCK and G6PC2 in regulating the pulsatility in insulin secretion thereby influencing insulin-signaling and leading to a gradual modulation in glucose levels in Italian patients with newly diagnosed T2D.

Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers.

The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å-1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.

Ultrafast Self-Induced X-Ray Transparency and Loss of Magnetic Diffraction.

Using ultrafast ≃2.5 fs and ≃25 fs self-amplified spontaneous emission pulses of increasing intensity and a novel experimental scheme, we report the concurrent increase of stimulated emission in the forward direction and loss of out-of-beam diffraction contrast for a Co/Pd multilayer sample. The experimental results are quantitatively accounted for by a statistical description of the pulses in conjunction with the optical Bloch equations. The dependence of the stimulated sample response on the incident intensity, coherence time, and energy jitter of the employed pulses reveals the importance of increased control of x-ray free electron laser radiation.

In vitro evaluation of the influence of velocity on sliding resistance of stainless steel arch wires in a self-ligating orthodontic bracket.

INTRODUCTION: Of the variables used by in vitro studies of resistance to sliding (RS) in orthodontics, sliding velocity (SV) of the wire is often the one farthest from its clinical counterpart. We investigated whether velocity influences the RS at values approximating the orthodontic movement. METHODS: A SS self-ligating bracket with a NiTi clip was fixed onto a custom-made model. Different shaped orthodontic SS wires of four sizes and two types (round, 0.020″ and 0.022″; rectangular, 0.016″×0.022″ and 0.017″×0.025″) were tested using an Instron® testing machine. Wires were pulled at four velocities (1×10-2  mm/s, 1×10-3  mm/s, 1×10-4  mm/s, 1×10-5  mm/s). Shapiro-Wilk test was used to evaluate the normal distribution of the data; two-way ANOVA was performed to compare means in the RS with wire characteristics and SV. Significance level was set at P<.05. RESULTS: RS was higher for rectangular wires, and for those with larger diameters. Lower SV was associated with lower RS, with wire type and size having an interaction effect. The RS relatively to SV can be represented as: RS ∝ α[ln(SV)]+ß, where α and ß are constants. CONCLUSIONS: At very low SV and low normal forces, SV influences the RS of SS archwires in orthodontic brackets, and the proportionality is logarithmic. Although respecting these parameters in vitro is challenging, quantitative evaluations of RS should be carried out at clinically relevant velocities if aiming at translational application in the clinical scenario.

THz-Driven Ultrafast Spin-Lattice Scattering in Amorphous Metallic Ferromagnets.

We use single-cycle THz fields and the femtosecond magneto-optical Kerr effect to, respectively, excite and probe the magnetization dynamics in two thin-film ferromagnets with different lattice structures: crystalline Fe and amorphous CoFeB. We observe Landau-Lifshitz-torque magnetization dynamics of comparable magnitude in both systems, but only the amorphous sample shows ultrafast demagnetization caused by the spin-lattice depolarization of the THz-induced ultrafast spin current. Quantitative modeling shows that such spin-lattice scattering events occur on similar time scales than the conventional spin conserving electronic scattering (∼30 fs). This is significantly faster than optical laser-induced demagnetization. THz conductivity measurements point towards the influence of lattice disorder in amorphous CoFeB as the driving force for enhanced spin-lattice scattering.

Is common genetic variation at IRS1, ENPP1 and TRIB3 loci associated with cardiometabolic phenotypes in type 2 diabetes? An exploratory analysis of the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 5.

BACKGROUND AND AIMS: Insulin resistance is a hallmark of type 2 diabetes (T2DM), it is often accompanied by defective beta-cell function (BF) and is involved in the pathophysiology of cardiovascular disease (CVD). Commonalities among these traits may recognize a genetic background, possibly involving the genetic variation of insulin signaling pathway genes. We conducted an exploratory analysis by testing whether common genetic variability at IRS1, ENPP1 and TRIB3 loci is associated with cardiovascular risk traits and metabolic phenotypes in T2DM. METHODS AND RESULTS: In 597 drug-naïve, GADA-negative, newly-diagnosed T2DM patients we performed: 1) genotyping of 10 independent single-nucleotide polymorphisms covering ∼ 90% of common variability at IRS1, ENPP1 and TRIB3 loci; 2) carotid artery ultrasound; 3) standard ECG (n = 450); 4) euglycaemic insulin clamp to assess insulin sensitivity; 5) 75 g-OGTT to estimate BF (derivative and proportional control) by mathematical modeling. False discovery rate of multiple comparisons was set at 0.20. After adjustment for age, sex and smoking status, rs4675095-T (IRS1) and rs4897549-A (ENPP1) were significantly associated with carotid atherosclerosis severity, whilst rs7265169-A (TRIB3) was associated with ECG abnormalities. Rs858340-G (ENPP1) was significantly associated with decreased insulin sensitivity, independently of age, sex and body-mass-index. No consistent relationships were found with BF. CONCLUSION: Some associations were found between intermediate phenotypes of CVD and common genetic variation of gatekeepers along the insulin signaling pathway. These results need be replicated to support the concept that in T2DM the CVD genetic risk clock may start ticking long before hyperglycemia appears. ClinicalTrials.gov Identifier: NCT01526720.

Direct Observation of a Localized Magnetic Soliton in a Spin-Transfer Nanocontact.

We report the direct observation of a localized magnetic soliton in a spin-transfer nanocontact using scanning transmission x-ray microscopy. Experiments are conducted on a lithographically defined 150 nm diameter nanocontact to an ultrathin ferromagnetic multilayer with perpendicular magnetic anisotropy. Element-resolved x-ray magnetic circular dichroism images show an abrupt onset of a magnetic soliton excitation localized beneath the nanocontact at a threshold current. However, the amplitude of the excitation ≃25° at the contact center is far less than that predicted (⪅180°), showing that the spin dynamics is not described by existing models.

X-ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu.

We have used a MHz lock-in x-ray spectromicroscopy technique to directly detect changes in magnetic moment of Cu due to spin injection from an adjacent Co layer. The elemental and chemical specificity of x rays allows us to distinguish two spin current induced effects. We detect the creation of transient magnetic moments of 3×10^{-5}µ_{B} on Cu atoms within the bulk of the 28 nm thick Cu film due to spin accumulation. The moment value is compared to predictions by Mott's two current model. We also observe that the hybridization induced existing magnetic moments at the Cu interface atoms are transiently increased by about 10% or 4×10^{-3}µ_{B} per atom. This reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow.

Spin-wave-mode coexistence on the nanoscale: a consequence of the Oersted-field-induced asymmetric energy landscape.

It has been argued that if multiple spin wave modes are competing for the same centrally located energy source, as in a nanocontact spin torque oscillator, that only one mode should survive in the steady state. Here, the experimental conditions necessary for mode coexistence are explored. Mode coexistence is facilitated by the local field asymmetries induced by the spatially inhomogeneous Oersted field, which leads to a physical separation of the modes, and is further promoted by spin wave localization at reduced applied field angles. Finally, both simulation and experiment reveal a low frequency signal consistent with the intermodulation of two coexistent modes.

First evidence of pep solar neutrinos by direct detection in Borexino.

We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.1±0.6{stat}±0.3{syst} counts/(day·100 ton). Assuming the pep neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9 counts/(day·100 ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic {11}C, the dominant background in the 1-2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×10{8} cm{-2} s^{-1} and <7.7×10{8} cm{-2} s{-1} (95% C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.

Role of monogenic diabetes genes on beta cell function in Italian patients with newly diagnosed type 2 diabetes. The Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 13.

We tested the hypothesis that common genetic variability of beta-cell genes responsible for monogenic diabetes may affect beta cell function in type 2 diabetes mellitus (T2DM). We studied 794 drug- naïve GAD-negative patients with newly diagnosed T2DM (age: median=59 years; I.Q. range: 52-66; body mass index: 29.3 kg/m2; 26.6-32.9). Beta-cell function was assessed by state-of-art mathematical modeling of glucose/C-peptide curves during a 240'-300' frequently sampled oral glucose tolerance test, to provide the beta-cell responses to the rate of increase in glucose concentration (derivative control: DC) and to glucose concentration (proportional control: PC). Forty-two single nucleotide polymorphism (SNPs), selected to cover over 90% of common genetic variability, were genotyped in nine monogenic diabetes genes: HNF4A, GCK, HNF1A, PDX1, HNF1B, NEUROD1, KLF11, KCNJ11 and ABCC8. Allelic variants of four SNPs (rs1303722 and rs882019 of GCK, rs7310409 of HNF1A and rs5219 of KCNJ11) were significantly associated with DC of beta-cell secretion (all P < 0.036). Allelic variants of four other SNPs (rs2868094 and rs6031544 of HNF4A, and rs1801262 and rs12053195 of NEUROD1) were associated with PC of beta-cell secretion (P < 0.02). In multivariate models, GCK, HNF1A and KCNJ11 SNPs explained 2.5% of the DC variability of beta-cell secretion, whereas HNF4A and NEUROD1 SNPs explained 3.6% of the PC variability of beta-cell secretion. We conclude that common variability of monogenic diabetes genes is significantly associated with an impaired beta-cell function in patients with newly diagnosed T2DM; thereby, these genes might be targeted by specific treatments in T2DM.

Precision measurement of the (7)Be solar neutrino interaction rate in Borexino.

The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)(-1.6)(+1.5)(syst) counts/(day·100 ton). This corresponds to a ν(e)-equivalent (7)Be solar neutrino flux of (3.10±0.15)×10(9) cm(-2) s(-1) and, under the assumption of ν(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. A global solar neutrino analysis with free fluxes determines Φ(pp)=6.06(-0.06)(+0.02)×10(10) cm(-2) s(-1) and Φ(CNO)<1.3×10(9) cm(-2) s(-1) (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.

Clinical and neuropsychological considerations in a case of unrecognized myoclonic epileptic jerks dramatically controlled by levetiracetam.

The International League Against Epilepsy (ILAE) classification recognizes 2 forms of myoclonic epilepsy with a good prognosis: benign myoclonic epilepsy of infancy (BMEI) and juvenile myoclonic epilepsy (JME); recent studies confirm the efficacy of levetiracetam (LEV) in treating idiopathic generalized epilepsies (IGE) in patients with myoclonic seizures. We report a girl referred to our Child Neuropsychiatry Unit at age 9 years because of massive myoclonic jerks, previously diagnosed as tics. Neuropsychological examination evidenced mild cognitive impairment. The clinical and electroencephalogram (EEG) data led to diagnosis of BMEI with late presentation. A dramatic suppression of interictal and ictal epileptiform activity was achieved after only one intake of LEV. Another neuropsychological examination after 6 months of treatment showed performance improvement probably related to EEG modifications. LEV may be suitable for the first-line treatment of myoclonic idiopathic seizures.

The SHOX gene: a new indication for GH treatment.

Short stature homeobox-containing (SHOX) gene mutations causing haploinsufficiency have been reported in idiopathic short stature, but the real prevalence of this defect in the population with growth failure is debated. Based on current data, the prevalence of SHOXdefect (SHOX-D) has been calculated to have occurred in at least 1 in 2,000 children. This occurrence rate is higher than that of classic GH deficiency or Turner syndrome. In all probability, the real prevalence of SHOX-D will increase in the future with the improvement of the genetic analysis with investigations for point mutations in the enhancer sequences or for deletions in other parts of this region. A selection criterion to individuate the most appropriate candidates eligible for the SHOX region analysis has been suggested based on the evaluation of a disproportional short stature. The efficacy of GH treatment in these patients has recently been demonstrated with results that are similar to those observed in Turner syndrome.

Oral implications of the vegan diet: observational study.

AIM: The aim of this study was to investigate oral changes in subjects who have assumed a vegan diet for a long time (at least 18 months), that is to say, a diet completely lacking in meat and animal derivatives. METHODS: A sample of 15 subjects was analyzed, all from northern Italy and aged 24 to 60 year, composed of 11 men and 4 women who had been following a vegan diet for a minimum of 18 months to a maximum of 20 years. In parallel with the study sample, a control group (15 subjects) with the same criteria of age, sex, and place of origin all following an omnivorous diet was chosen. The sample answered a questionnaire that investigated their eating habits, the frequency with which they eat meals, the main foodstuffs assumed, oral hygiene habits, and any painful symptomatology of the teeth or more general problems in the oral cavity. The sample was then subject to objective examination in which the saliva pH was measured and the teeth were checked for demineralization of the enamel, white spots, and caries (using KaVo DIAGNOdent) with particular attention being paid to the localization of these lesions, and lastly, sounding was carried out to detect any osseous defects and periodontal pockets. RESULTS: The study revealed greater incidence of demineralization and white spots in the vegan subjects compared to the omnivorous ones localized at the neck of the teeth and on the vestibular surfaces of dental elements (with the exception of the lower anterior group). The saliva pH, more acid in the omnivorous patients, ranged between four and six. Changes in oral conditions in both groups of subjects were observed. CONCLUSION: In order to research into the cause-effect relationship of the vegan diet on the oral cavity effectively, the sample needs to be studied for a longer period of time and the results re-evaluated.

Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys.

Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. However, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism. A hydrodynamic representation of the numerical simulations indicates that the appearance of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 107 A cm-2. Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. The magnon processes discussed here provide new insights for the stabilization of desired meta-stable states.

On the theory of drainage area for regular and non-regular points.

The drainage area is an important, non-local property of a landscape, which controls surface and subsurface hydrological fluxes. Its role in numerous ecohydrological and geomorphological applications has given rise to several numerical methods for its computation. However, its theoretical analysis has lagged behind. Only recently, an analytical definition for the specific catchment area was proposed (Gallant & Hutchinson. 2011 Water Resour. Res.47, W05535. (doi:10.1029/2009WR008540)), with the derivation of a differential equation whose validity is limited to regular points of the watershed. Here, we show that such a differential equation can be derived from a continuity equation (Chen et al. 2014 Geomorphology219, 68-86. (doi:10.1016/j.geomorph.2014.04.037)) and extend the theory to critical and singular points both by applying Gauss's theorem and by means of a dynamical systems approach to define basins of attraction of local surface minima. Simple analytical examples as well as applications to more complex topographic surfaces are examined. The theoretical description of topographic features and properties, such as the drainage area, channel lines and watershed divides, can be broadly adopted to develop and test the numerical algorithms currently used in digital terrain analysis for the computation of the drainage area, as well as for the theoretical analysis of landscape evolution and stability.

Autologous micro-fragmented adipose tissue for the treatment of diffuse degenerative knee osteoarthritis: an update at 3 year follow-up.

BACKGROUND: Conservative therapies for the treatment of knee degenerative processes are used before resorting to surgery; nonetheless, they may offer only short-term benefits. Encouraging preliminary results have been reported using mesenchymal stem cells (MSCs), either alone or in association with surgery. Among the many sources, adipose tissue has created a huge interest, because of its anti-inflammatory and regenerative properties ascribed to the cells of its stromal vascular fraction. We previously reported the safety and feasibility of autologous micro-fragmented adipose tissue as adjuvant for the surgical treatment of diffuse degenerative chondral lesions at 1 year. Here we present the outcomes of the same cohort of patients evaluated at 3 year follow-up. Micro-fragmented adipose tissue was obtained using a minimal manipulation technique in a closed system. The safety of the procedure was evaluated by recording type and incidence of any adverse event. The clinical outcomes were determined using the KOOS, IKDC-subjective, Tegner Lysholm Knee, and VAS pain scales taken pre-operatively and at 12 and 36 months follow-up. FINDINGS: No adverse events, lipodystrophy cases at the harvesting site nor atypical inflammatory reactions at the joint level were reported. Of the 30 patients previously treated, one was lost, and seven received additional treatments in the period of observation. On average, the 22 patients that had no other treatments in the 3-year period showed that the results observed at 1 year were maintained. Moreover, 41, 55, 55 and 64% of the patients improved with respect to the 1-year follow-up in the Tegner Lysholm Knee, VAS, IKDC-subjective and total KOOS, respectively. CONCLUSION: Our results point to autologous and micro-fragmented adipose tissue injection as an innovative and safe approach for the management of diffuse degenerative knee chondropathy in the mid-term. The procedure is simple, affordable, minimally invasive, and compliant with the regulatory panorama.