L2,3-edges absorption spectra of a 2D complex system: a theoretical modelling.

L2,3-edges absorption spectra of FePc (I) and FePc(η2-O2) (II) on Ag(110) have been modelled using the DFT/ROCIS method. Despite disregarding the presence of the substrate, the agreement between experiment and theory is remarkable. Moreover, theoretical results confirm the fraction of II (70%) present on the surface, thus allowing a thorough assignment of each experimental spectral feature. Ground state (GS) theoretical outcomes pertaining to I and II provide an intimate understanding of the electron transfer pathway ruling the I-based catalytic oxygen reduction reaction. DFT/ROCIS outcomes indicate that the lower excitation energy (EE) side of the I/IIL3 intensity distributions mainly includes states having the GS number of unpaired electrons (two in I and six in II), whereas states with higher/lower spin multiplicity contribute to the I/IIL3 higher EE side. The occurrence of states involving metal to ligand charge transfer transitions implying low lying empty π* ligand-based orbitals on the I/IIL3 higher EE sides have been confirmed.

High-resolution imaging of remanent state and magnetization reversal of superdomain structures in high-density cobalt antidot arrays.

Remanent state and magnetization reversal processes of a series of cobalt antidot arrays with a fixed hole diameter (d ≈ 55 nm) and an array periodicity (p) ranging between 95 and 524 nm were studied by in situ Lorentz microscopy (LM) as a function of the magnetic field. At remanence, defocused LM images showed the periodicity dependence of the magnetic states inside the lattice. A remarkable transition was observed in the type of domain structures as a function of p: for the large periodicities (p > 300 nm), conventional 90° and 180° domain walls were formed, whereas in small-period antidot arrays (p â‰¦ 160 nm) magnetic superdomain walls (SDWs) were nucleated to separate regions with different average magnetization direction, the so-called magnetic superdomains. In the SDW regime, a low-frequency Fourier filtering method was implemented to allow a quantitative analysis of the LM images by the transport of intensity equation method. In situ LM experiments under applied magnetic fields were performed to study the reversal magnetization process in a particular array (p = 160 nm), and clear differences were observed as a function of the magnetic field orientation. The switching process under magnetic fields parallel to the horizontal antidot rows occurs in two stages: the system first nucleates and propagates horizontal SDWs, parallel to the field. Then, at higher magnetic fields, vertical SDWs, perpendicular to the field, appear before saturation. When the magnetic field is applied at 45° with respect to the antidot rows, both horizontal and vertical SDWs are nucleated and propagated simultaneously. All the experiments were successfully correlated with micromagnetic simulations. The current study sheds new light on the magnetization reversal processes of antidot arrays and opens new possibilities of exploiting the potential of high-resolution in situ LM and new data analysis procedures to probe magnetization processes in nanomagnetism, particularly in periodic arrays of nanomagnets.

SiO2 coating effects in the magnetic anisotropy of Fe3-xO4 nanoparticles suitable for bio-applications.

We present radio frequency transverse susceptibility (TS) measurements on oleic acid-coated and SiO2-coated Fe3-xO4 magnetite nanoparticles. The effects of the type of coating on the interparticle interactions and magnetic anisotropy are evaluated for two different particle sizes in powder samples. On the one hand, SiO2 coating reduces the interparticle interactions as compared to oleic acid coating, the reduction being more effective for 5 nm than for 14 nm diameter particles. On the other hand, the magnetic anisotropy field at low temperature is lower than 1 kOe in all cases and independent of the coating used. Our results are relevant concerning applications in biomedicine, since the SiO2 coating renders 5 and 14 nm hydrophilic particles with very limited agglomeration, low anisotropy, and superparamagnetic behavior at room temperature. The TS technique also allows us to discriminate the influence on the anisotropy field of interparticle interactions from that of the thermal fluctuations.

Strong paramagnetism of gold nanoparticles deposited on a Sulfolobus acidocaldarius S layer.

Magnetic properties of Au nanoparticles deposited on an archaeal S layer are reported. X-ray magnetic circular dichroism and superconducting quantum interference device magnetometries demonstrate that the particles are strongly paramagnetic, without any indication of magnetic blocking down to 16 mK. The average magnetic moment per particle is M(part)=2.36(7) µ(B). This contribution originates at the particle's Au 5d band, in which an increased number of holes with respect to the bulk value is observed. The magnetic moment per Au atom is 25 times larger than any measured in other Au nanoparticles or any other configurations up to date.

Fabrication and magnetic characterization of cobalt antidot arrays: effect of the surrounding continuous film.

We have performed an experimental study on the influence of a ferromagnetic continuous film in the magnetization reversal processes in discrete submicrometric antidot arrays fabricated on it. In order to compare the magnetic properties, two sets of antidot arrays have been fabricated over a cobalt thin film: embedded in the continuous film, and isolated by a trench surrounding the array. X-ray photoemission electron microscopy images of the virgin state show the same magnetic domain distribution in both sets of samples, finding no evidence of any effect of the surrounding film. This result is supported by the hysteresis loops measured with magneto-optical Kerr effect, as isolated and non-isolated arrays present almost coincident loops. A huge increase of the coercivity of the film is achieved, and the expected dependence on the geometrical parameters of the array is found, connecting the previous studies on the micro- and nanometric scales.

Evolution of Fe magnetic order in NdFexGa 1- xO3.

The evolution of the crystal structure and magnetic properties with Fe content in NdFe(x)Ga(1 - x)O(3) has been studied by magnetization, ac-susceptibility, x-ray and neutron scattering techniques for x ≥ 0.2 in order to determine the phase diagram of the series. X-ray diffraction shows that the crystallographic structure of NdFe(x)Ga(1 - x)O(3) can be described in the space group Pbnm for all x values. Both the magnetic ordering and spin reorientation temperatures of the Fe magnetic sublattice decrease with iron concentration due to the presence of magnetic vacancies occupied by Ga. The long-range Fe magnetic ordering disappears for x ≤ 0.3, while ac-susceptibility measurements evidence the presence of short-range Fe ordered clusters and superspin-glass-like effects for x well below the percolation threshold. The magnetic structure of the compounds, including the spin reorientation temperature range, is determined by high-resolution neutron diffraction analysis. Although the presence of finite magnetic clusters for x values close to percolation is evidenced, the study of a percolation quantum phase transition in this series is hindered by the presence of Nd magnetic moments and a sizeable distribution of composition Δx around the nominal value.

Ocular manifestations of SARS-CoV-2: Literature review. / Manifestaciones oftalmológicas del SARS-CoV-2: Revisión de la literatura.

In this review, a summary is presented of the main reports regarding the potential ocular manifestations of the new coronavirus disease (COVID-19). Scientific evidence is based on letters to the editor, clinical cases and case series, cross-sectional, and a few longitudinal studies. To date, it includes viral conjunctivitis, immune conjunctivitis, and oculomotor palsies (OCP) due to the novel coronavirus. Retinopathy is discussed. A viral conjunctivitis outbreak can be isolated or associated with the systemic picture, mainly pulmonary, before or after the onset of respiratory symptoms. It can be both unilateral and bilateral, follicles are typical, and duration is variable between 5 and 21 days. Immune-mediated conjunctivitis consists of eye redness, together with erythroderma and fever. It appears more frequently in children, and has been associated with a «Kawasaki-like¼ disease and toxic shock syndrome. OCP can present on its own, or as part of Miller-Fisher syndrome, along with ataxia, and hyporeflexia. Ophthalmologists have a considerable risk of developing COVID-19 due to close contact with the patient, exposure to tears and eye secretions, and the use of various pieces of equipment and devices susceptible to contamination.

On the mechanism of inhibition of p27 degradation by 15-deoxy-Delta12,14-prostaglandin J2 in lymphoblasts of Alzheimer's disease patients.

It has been proposed that neuroinflammation, among other factors, may trigger an aberrant neuronal cell cycle re-entry leading to neuronal death. Cell cycle disturbances are also detectable in peripheral cells from Alzheimer's disease (AD) patients. We previously reported that the anti-inflammatory 15- deoxy-Delta(12,14)-prostaglandin J (2) (15d-PGJ (2)) increased the cellular content of the cyclin-dependent kinase inhibitor p27, in lymphoblasts from AD patients. This work aimed at elucidating the mechanisms of 15d-PGJ (2)-induced p27 accumulation. Phosphorylation, half-life, and the nucleo-cytoplasmic traffic of p27 protein were altered by 15d-PGJ2 by mechanisms dependent on PI3K/Akt activity. 15d-PGJ (2) prevents the calmodulin-dependent Akt overactivation in AD lymphoblasts by blocking its binding to the 85-kDa regulatory subunit of PI3K. These effects of 15d-PGJ (2) were not mimicked by 9,10-dihydro-15-deoxy-Delta(12,14)- prostaglandin J (2), suggesting that 15d-PGJ (2) acts independently of peroxisome proliferator-activated receptor gamma activation and that the alpha,beta-unsaturated carbonyl group in the cyclopentenone ring of 15d-PGJ (2) is a requisite for the observed effects.

High relaxation barrier in neodymium furoate-based field-induced SMMs.

Two new neodymium molecular magnets of formula {[Nd(α-fur)3(H2O)2]·DMF}n (1) and {[Nd0.065La0.935(α-fur)3(H2O)2]}n (2), α-fur = C4H3OCOO, have been synthesized. In (1) the furoate ligands, in bidentate bridging mode, consolidate zig-zag chains running along the a-direction. Compound (2) is a magnetically diluted complex of a polymeric chain along the b-axis. Heat capacity, dc magnetization and ac susceptibility measurements have been performed from 1.8 K up to room temperature. Ab initio calculations yielded the gyromagnetic factors gx* = 0.52, gy* = 1.03, gz* = 4.41 for (1) and gx* = 1.35, gy* = 1.98, gz* = 3.88 for (2), and predicted energy gaps of Δ/kB = 125.5 K (1) and Δ/kB = 58.8 K (2). Heat capacity and magnetometry measurements agree with these predictions, and confirm the non-negligible transversal anisotropy of the Kramers doublet ground state. A weak intrachain antiferromagnetic interaction J'/kB = -3.15 × 10-3 K was found for (1). No slow relaxation is observed at H = 0, attributed to the sizable transverse anisotropy component, and/or dipolar or exchange interactions enhancing the quantum tunnelling probability. Under an external applied field as small as 80 Oe, two slow relaxation processes appear: above 3 K the first relaxation mechanism is associated to a combination of Orbach process, with a sizeable activation energy U/kB = 121 K at 1.2 kOe for (1), Raman and direct processes; the second, slowest relaxation mechanism is associated to a direct process, affected by phonon-bottleneck effect. For complex (2) a smaller U/kB = 61 K at 1.2 kOe is found, together with larger g*-transversal terms, and the low-frequency process is quenched. The reported complexes represent rare polymeric Nd single-ion magnets exhibiting high activation energies among the scarce Nd(iii) family.

Post-herpes neurotrophic keratopathy: Aetiopathogenesis, clinical signs and current therapies. / Queratopatía neurotrófica postherpética: etiopatogenia, clínica y terapias actuales.

Neurotrophic keratopathy (NK) is a degenerative corneal disease caused by damage of trigeminal innervation. This leads to epithelial defects, ulceration and, eventually, perforation. Both herpes simplex and varicella zoster keratitis are reported to be the main causes of NK. Furthermore, prognosis in this type of NK is poor. Classic clinical findings in post-herpes NK are spontaneous epithelial breakdown, round and central epithelial defects with smooth edges, stromal melting and thinning, scarring, and neovascularisation. Although several medical and surgical treatments have been reported, no therapies are currently available to definitely restore corneal sensitivity. Therefore, NK remains a challenging disease to treat. In this review a summary is presented of the pathogenesis, manifestations, and current management of post-herpes NK. The role of antiviral treatment and varicella-zoster vaccination is also discussed. A description is also presented on both medical and surgical novel therapies, such as regenerative drugs and corneal neurotization.

[Electrophysiological effects of sevoflurane in comparison with propofol in children with Wolff-Parkinson-White syndrome]. / Efectos electrofisiológicos del sevoflurano versus propofol en niños con síndrome de Wolff-Parkinson-White.

OBJECTIVE: To evaluate the electrophysiological effects of sevoflurane in children with Wolff-Parkinson-White (WPW) syndrome undergoing radiofrequency ablation. METHODS: We performed a prospective study of 15 patients with WPW syndrome who were scheduled for an electrophysiological study (EPS) and radiofrequency ablation. Anesthesia was induced with fentanyl (2 microg/kg), propofol (3 mg/kg), and vecuronium (0.1 mg/kg), and initially maintained using propofol (100 microg/kg), with bolus administration of fentanyl and vecuronium as required. Four intracardiac catheters were introduced for the EPSpropofol, which included measurements of sinus-node function, sinoatrial-node conduction, refractory periods (atrial, AV-node, accessory pathway anterograde and retrograde, and ventricular), and the characteristics of induced orthodromic tachycardia. The propofol was then replaced with sevoflurane (1 MAC adjusted for age) and the measurements were repeated (EPSsevoflurane). The EPSpropofol and EPSsevoflurane data were compared using the Wilcoxon signed-rank test. RESULTS: The mean (SD) age was 9.3 (6) years. After administration of sevoflurane, the duration of the antegrade effective refractory period of the accessory pathway increased (EPSpropofol, 283 (22) ms; EPSsevoflurane, 298 (25) ms; P = .004), as did the duration of the minimum pacing cycle with 1:1 atrioventricular conduction (EPSpropofol, 244 (41) ms; EPSsevoflurane, 273 (28) ms; P = .028). No significant changes were observed in the other parameters. Ablation of the accessory pathway was achieved in all patients. CONCLUSIONS: Sevoflurane partially modified the properties of the accessory pathway but did not prevent ablation.

Cerebral oximetry monitoring in the management of severe hypoxaemia associated with transposition of the great arteries with balloon atrial septostomy. / Monitorización de la oximetría cerebral en el manejo de la hipoxemia severa asociada a la transposición de grandes arterias mediante atrioseptostomía con balón.

Transposition of the great arteries (D-TGA) is one of the most common congenital heart diseases requiring neonatal surgical intervention. In the desperately ill neonate with TGA and the resultant hypoxaemia, acidemia, and congestive heart failure, improvement is often obtained with balloon atrial septostomy (BAS). Current methods employed to evaluate oxygen delivery and tissue consumption are frequently nonspecific. Near infrared spectroscopy (NIRS) allows a continuous non-invasive measurement of tissue oxygenation which reflects perfusion status in real time. Because little is known about the direct effect of BAS on the neonatal brain and on cerebral oxygenation, we measured the effectiveness of BAS in two patients with D-TGA using NIRS before and after BAS. We concluded BAS improves cerebral oxygen saturation in neonates with D-TGA.

Assessment of ocular redness measurements obtained with keratograph 5M and correlation with subjective grading scales.

OBJECTIVE: To examine correlations between ocular redness scores provided by the Keratograph 5M and those determined using two image-based grading scales. METHODS: Observational prospective cross-sectional study. Two hundred and twenty six eyes of two hundred and twenty six participants (175 patients using anti-glaucoma eye drops and 51 subjects untreated). All subjects were scored automatically using the keratograph 5M. These redness scores (RS) were then correlated with the gradings provided by the Efron and McMonnies/Chapman-Davies scale (MC-D) scales (two observers). RESULTS: Excellent reproducibility was observed for both the Efron (weighted K=0.897, 95% CI 0.823-0.904) and MC-D (weighted K=0.783, 95% CI 0.752-0.795) scales. Keratograph RS and the scores obtained with both Efron (Spearman's Rho=0.43, P<0.001) and MC-D (Spearman's Rho=0.48, P<0.001) scales were significantly correlated. RS for the bulbar and limbal - nasal and temporal quadrants also correlated moderately with the two subjective scales. Through Bland Altman analysis, poor agreement was detected between the objective and subjective methods: agreement values for the Efron scale or MC-D scale (matching scorers between observers) versus overall RS showed high biases (-15.58 and -22.05 respectively) and wide limits of agreement (LOA) (-46.169 to 15.005 and -52.534 to 8.19 respectively). Lowest bias was observed between temporal limbal RS and Observer 2 Efron score (-0.04). CONCLUSIONS: Although it emerged as a reliable objective method, the keratograph 5M overestimated the scores compared with the subjective grading scales when used to grade the degree of ocular redness. Therefore, they should not be interchangeable methods.

Study of the relationship between myopia and personality.

OBJECTIVE: To study the correlation between the myopic refractive error and certain personality traits, and to determine whether there is a correlation between the degree of myopia and an increased frequency in personality disorders. METHODS: Cross-sectional observational multicenter study conducted on 82 subjects (26 men, 56 women) age over 18 years with myopia (spherical defect ≤ -0.5 D), with 30 subjects having high myopia (<-6 D). DATA COLLECTED: age and gender, academic level, result in the Neo PI-R personality test, autorefractometry, myopic pathology, and ophthalmological treatment. RESULTS: Correlation (Spearman's) between the magnitude of the spherical defect and the 5 personality traits studied in the total sample was not statistically significant: neuroticism (-0.057; P=.610), extroversion (-0.020; P=.857), openness (-0.032; P=.774), kindness (-0.060; P=.592), and responsibility (-0.034; P=.765). By dividing them into subgroups of low and high significance (t-test), a significant (P=.002) upward trend of the myopic defect with increasing scores on extraversion was found. When comparing high myopic subjects to the non-high myopic ones, there were significant differences between the 2 groups in terms of the associated pathology (P=.001), received treatment (P=.001) and the level of studies (P=.013). There were no differences in the variables of personality: neuroticism (P=.852), extroversion (P=.199), openness (P=.560), kindness (P=.584), and responsibility (P=.722). CONCLUSIONS: A low correlation was found between myopia and personality. There was no difference in the degree of myopia between the groups with different education levels. Subjects with more severe ocular pathology associated with myopia had higher scores in neuroticism, without finding any significant association.

Orbital magnetic moment instability at the spin reorientation transition of Nd2Fe14B

Highly accurate soft-XMCD data recorded on a Nd2Fe14B single crystal, through the spin reorientation transition show that the average Fe orbital moment (a) is proportional to the macroscopic Fe anisotropy constant, and (b) diverges 15 K below the reorientation transition temperature. This divergence is indicative of a critical behavior and it is related to a tetragonal distortion. These results give experimental evidence of the mutual dependence between orbital moment, macroscopic magnetic anisotropy, and tetragonal distortion. Furthermore, it is argued that the critical behavior of the orbital moment is at the origin of similar divergences previously observed in Mossbauer and Hall-effect data.

Receptors for polymerized human serum albumin and other hepatitis B virus markers during acute hepatitis B--predictive value of the outcome of the disease.

Polymerized human serum albumin virus receptors (pHSA-R) HBsAg, HBeAg, antiHBc-IgM, hepatitis B virus (HBV) DNA polymerase activity and HBV-DNA were studied in 47 acute hepatitis B patients, divided into three groups: 26 HBeAg(+) initially, with favorable outcome; 4 HBeAg (+), with chronic outcome; and 17 antiHBe (+), with favorable outcome. In the basal sample only 2 and 8 patients in Group I were HBV-DNAp and HBV-DNA positive, respectively, and became negative during the follow-up. In contrast all patients in Group II remained positive to both HBV-markers. After a one-month follow-up 100% of the patients in Group II were positive for pHSA-R and HBeAg, in contrast to 25% among those with a favorable outcome in Group I (p less than 0.005). Meanwhile, only 6 out of 17 patients in Group III remained positive for pHSA-R. A significant decrease in pHSA-R and HBsAg concentrations was observed in patients from Group I (p less than 0.005 and p less than 0.05, respectively) 15 days after the onset of the disease, while concentrations of both parameters did not vary in Group II. A significant decrease in HBsAg and pHSA-R concentrations was found in patients from Group III after 15 days (p less than 0.05) and one month follow-up (p less than 0.05), respectively. As a result, pHSA-R and HBeAg are the best prognostic indicators in acute hepatitis B. A decrease in HBsAg and pHSA-R concentrations two weeks after the onset may have predictive value.

[Congenital stenosis of pulmonary veins: long-term efficacy after intraluminal dilatation]. / Estenosis congénita de venas pulmonares: eficacia a largo plazo tras dilatación intraluminal.

We present a 7-month-old infant diagnosed with congenital pulmonary vein stenosis. Cardiac catheterization showed two sequential stenoses of the superior left pulmonary vein and balloon angioplasty was performed. The gradient decreased from 20 to 4 mmHg and pulmonary artery pressure from 75/35 mmHg to 44/28 mmHg. The diameter of the stenoses increased from 2 and 3.5 mm, respectively, to 6 mm. Fourteen years after the procedure the patient is asymptomatic with normal cardiac examination.