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.

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.

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.

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.

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.

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.

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.

Large orbital magnetic moment in Pt13 clusters.

We present an extensive study of Pt13 clusters embedded in a Na-Y zeolite, by comparing calculations for isolated clusters to experimental data. We perform structural refinements for various geometries involving the isolated clusters and calculate the corresponding x-ray absorption and magnetic circular dichroism spectra, from the joint perspective of pseudopotential plane wave calculations and real space multiple scattering theory. Taking into account the spin-orbit coupling significantly improves the previous scalar relativistic predictions of magnetic properties. The ensemble of embedded Pt13 is found to be dominated by a non-magnetic cuboctahedral geometry. One of the implications is that the ground state of Pt13 clusters in the zeolite environment is different from that of isolated particles. We investigate several isomers that yield a magnetic signature. Furthermore, their abundance was estimated by direct comparison with experiment. We found that one third of the magnetic moment of Pt13 comes from the orbital contribution, in agreement with the experimental value. We therefore provide theoretical proof of the extraordinary orbital magnetization in Pt13 clusters.

Parimagnetism in HoCo2 and TmCo2.

X-ray magnetic circular dichroism (XMCD), longitudinal (χac) and transverse (TS) ac magnetic susceptibility have been measured in the RCo2 series (R = Ho, and Tm) as a function of temperature and applied magnetic field. We show that parimagnetism is a general behavior among the RCo2 ferrimagnetic series (R being a heavy rare-earth ion). XMCD results supply evidence of the presence of two compensation temperatures above Tc, defining two different parimagnetic configurations, which is a fully unexpected result. The inverse χ'ac curve exhibits a small anomaly which vanishes under low applied magnetic fields. The combination of TS and XMCD measurements allows one to depict new magnetic phase diagrams for these compounds of the RCo2 series. A new scenario allowing one to understand the observed phenomenology as a Griffiths phase-like behavior is proposed, where the amorphous RCo2 represents the undiluted system case.

Multiferroic (ferroelastic/ferromagnetic/ferrimagnetic) aspects of phase transitions in RCo2 Laves phases.

Magnetic phase transitions in RCo2 Laves phases with R as a rare earth element are accompanied by changes in crystallographic space group. For purely structural transitions they would be described as improper ferroelastic and therefore fulfil the condition for multiferroic phase transitions in combining two out of three properties, ferro/antiferromagnetism, ferroelectricity and ferroelasticity. Here lattice parameter data from the literature and new measurements of elastic and anelastic properties, by resonant ultrasound spectroscopy, for NdCo2 and ErCo2 have been analysed from this perspective. The temperature dependence of symmetry-breaking shear strains is consistent with the cubic ↔ tetragonal transition in NdCo2 being close to tricritical in character and the cubic ↔ rhombohedral transition in ErCo2 being first order. Elastic softening and acoustic loss within the stability ranges of the ferroelastic phases can be understood in terms of a combination of intrinsic softening due to strain/order parameter coupling and ferroelastic twin-wall motion. Softening ahead of the transitions does not fit with standard macroscopic descriptions of dynamic effects from other systems but, rather, in the case of NdCo2, might be attributed to the involvement of a second zone centre order parameter related to a separate instability driven by cooperative Jahn-Teller distortions. In ErCo2, acoustic loss in the temperature interval above the transition point is discussed in terms of a possible tweed microstructure associated with strain coupling to local magnetic ordering. The overall multiferroic behaviour can be understood in terms of a single magnetic order parameter (irrep mΓ+4 of magnetic space group Fd3m1') which couples with a structural order parameter (irrep Γ+3 or Γ+5). The coupling is linear/quadratic which, in the case of two separate instabilities, causes them to combine in a single multiferroic phase transition.

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.

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.