Exploring Structural Features and Growth Mechanisms in GdBa2Cu3O7-x /LaFeO3 Bilayers on SrTiO3 Substrates.

This study investigated a novel approach to enhance the performance of superconductors by applying a LaFeO3 (LFO) buffer layer on a GdBa2Cu3O7-x (GdBCO) superconducting thin film. LFO is a rare-earth orthoferrite (REFO) materials. The objective was to assess how the thickness of the LFO layer influences the superconducting properties of the GdBCO material. LFO layers were fabricated at thicknesses of 50, 100, 150, and 200 nm, and subsequently, a 200 nm thick layer of GdBCO was deposited to create a bilayer structure. This study represents the first utilization of a REFO material, specifically LFO, as a buffer layer, with findings showing its growth in a pseudocubic structure. We thoroughly examined the characteristics of LFO, including its structural, surface, and strain states, focusing on the impact of varying layer thicknesses. Additionally, we investigated changes within the GdBCO/LFO bilayer and analyzed how LFO influences the properties of GdBCO. It was found that the application of the LFO buffer layer by varying thicknesses not only provided structural compatibility with GdBCO but also consistently resulted in the improvement of its superconducting transition temperature, as evidenced by the enhanced Tc-onset values reaching up to 92.4 K with an LFO thickness of 150 nm. These findings reveal significant potential in utilizing REFO materials, particularly those derived from LFO, as effective buffer layers in superconductor applications.

Enhancement in High-Field J c Properties and the Flux Pinning Mechanism of ZnO-Buffered MgB2 Films.

We investigated the flux pinning properties in terms of the critical current density (J c) and pinning force density (F p) of MgB2 films with ZnO buffer layers of various thicknesses. At higher thicknesses of the buffer layer, significantly larger J c values are observed in the high-field region, whereas J c values in the low- and intermediate-field regions remain largely unaffected. A secondary point-pinning mechanism other than primary grain boundary pinning is observed in the F p analysis, which depends on the thickness of the ZnO buffer layer. Moreover, a close relationship between the Mg and B bond ordering and the fitting parameter of secondary pinning is obtained, indicating that the local structural distortion of MgB2 induced by ZnO buffer layers with different thicknesses may contribute to flux-pinning enhancement in the high-field region. Discovering further advantages of ZnO as a buffer layer other than the delamination resistance it provides will help to develop a MgB2 superconducting cable with a high J c for power applications.

Specific Location of Disc Hemorrhage is Linked to Nerve Fiber Layer Defects.

PURPOSE: To investigate the relationship between retinal nerve fiber layer (RNFL) defects and the quadrant and proximal location of disc hemorrhages (DHs) in a large population examined for health screening. METHODS: A total of 168,044 subjects older than 20 years underwent a single screening ophthalmic examination with color fundus photography as part of a comprehensive health screening program. The presence and location of DHs and RNFL defects were assessed. The DH locations were defined according to the quadrant location (inferotemporal, superotemporal, inferonasal, or superonasal) and the most proximal end of DHs relative to the disc center (cup base, cup margin, disc rim, or extrapapillary region). Using these two location descriptors as independent variables, a logistic regression analysis was conducted to explore the effects of DH location on RNFL defects. RESULTS: Two hundred twenty-six eyes had DH and 120 (53.1%) of them had RNFL defects. After adjusting for proximal location, DHs located in the inferotemporal quadrant accompanied RFNL defects 12 times more frequently than those in the superonasal quadrant (odds ratio [OR], 11.81; P = .004). Conversely, after adjusting for quadrant location, the ORs for an associated RNFL defect were 3.73 (P < .001), 16.54 (P < .001), and 8.91 (P = .002) for DHs with the proximal end at the disc rim, cup margin, and cup base, respectively. CONCLUSIONS: Among the four quadrants and four proximal locations, DHs were identified most frequently in the inferotemporal quadrant and outside the disc, respectively. Some DH locations, such as the inferotemporal quadrant and the cup margin, were associated with RNFL defects, whereas others were not.

Diurnal intraocular pressure changes in eyes affected with acute primary angle closure and fellow eyes after laser peripheral iridotomy.

PURPOSE: To evaluate diurnal curves of intraocular pressure (IOP) in eyes affected with unilateral acute primary angle closure (APAC) after laser peripheral iridotomy (LPI), and fellow eyes. METHODS: The medical records of 22 female patients (44 eyes) with unilateral APAC and LPI performed OU were reviewed along with those of 48 normal control subjects (48 eyes). None of the subjects used glaucoma medications after LPI. IOP was measured with a Goldman applanation tonometer during waking hours and in a sitting position every 2 h between 09:00 and 23:00. IOP profiles were compared including the means, peaks, trough IOPs, and IOP fluctuations of the affected, fellow, and normal eyes. RESULTS: The IOPs of the affected eyes were significantly higher than those of normal eyes at every time point measured, including peak and trough IOPs. The diurnal IOPs of fellow eyes were higher than those of normal eyes, though not significantly. There were no significant differences in IOP fluctuation between the affected, fellow, and normal eyes. IOP diurnal curves for APAC affected, fellow, and normal eyes were not statistically different (repeated measures ANOVA, p = 0.865). The mean coefficient of IOP in affected and fellow eyes ranged from 0.486 to 0.604. CONCLUSIONS: There were no clinically significant differences among the three groups in terms of IOP diurnal curves, and thus LPI did not have a significant effect on diurnal patterns of IOP. Though the diurnal IOPs of affected eyes after LPI was significantly higher than those of normal eyes, the IOP range was not acute.

In Vivo Assessment of Pharmacologic Vitreolysis in Rabbits With the Digital Fluoroscopy System.

PURPOSE: The purpose of this study was to demonstrate the efficacy of the digital fluoroscopy system (DFS) for the in vivo assessment of pharmacologically induced posterior vitreous detachment (PVD) and vitreous liquefaction in a rabbit model. METHODS: Twenty eyes from 10 New Zealand white rabbits were divided into 5 groups. In each group, one rabbit received an intravitreal injection of 2.0 U plasmin in the right eye and 0.5 U plasmin in the left eye. Intravitreal injection of 0.1 mL balanced salt solution (BSS) was given in the right eye, and no injection was given in the left eye of another rabbit used as a control. Intraocular fluid dynamics were assessed by the DFS, using a contrast agent in each group at different time intervals (6 hours, 12 hours, 1 day, 3 days, and 7 days). After rabbits were killed, both eyes were enucleated. Scanning electron microscopy was used to confirm the morphological alterations of the vitreoretinal interface as observed in the DFS. RESULTS: Complete PVD was observed after 12 hours with 2.0 U plasmin injection, whereas complete PVD was observed only after 3 days in eyes injected with 0.5 U plasmin. Eyes that received BSS injection or did not receive an injection failed to show complete PVD even after 7 days. Complete vitreous liquefaction was observed after 7 days with 2.0 U plasmin injection, but no eyes with 0.5 U plasmin or BSS injection showed complete liquefaction. We could clearly confirm the presence of PVD and the degree of vitreous liquefaction by using DFS. CONCLUSIONS: Digital fluoroscopy system appears to be a useful tool for the evaluation of pharmacological vitreolysis in rabbits with clear in vivo visualization of PVD and vitreous liquefaction.

Disc hemorrhages and their risk factors in an urban South Korean population.

PURPOSE: The aim of this study was to estimate the prevalence of disc hemorrhage (DH) and evaluate its related risk factors in an urban South Korean population. METHODS: This retrospective cross-sectional study included subjects who underwent health screening at the Health Screening Center of Kangbuk Samsung Hospital from August 2012 to July 2013. All fundus photographs were first reviewed by two ophthalmologists and then by two glaucoma specialists and one retina specialist to determine the presence of DHs. In addition to fundus photographs, each participant completed systemic examination as well as sociodemographic and behavioral questionnaires. RESULTS: Fundus photographs were available for 164,029/168,044 (97.61%) subjects 20 years and older. The prevalence of DH was 226/164,029 (0.14%; 95% confidence interval, 0.12 to 0.16) per subject. A large proportion (61.5%) of eyes with DH had localized wedge-shaped retinal nerve fiber layer defects indicative of glaucoma. There was also a slight increase in DH prevalence with age, but no other statistically significant associations were found. CONCLUSIONS: The prevalence of DH was 0.14% in urban South Korean subjects 20 years and older. Older age and the presence of glaucomatous retinal nerve fiber layer defects were associated with higher prevalence of DH. These findings suggest that the presence of a DH in an eye implies a high likelihood of glaucoma, although its absence does not indicate that glaucoma is absent.

A patient with branch retinal vein occlusion accompanied by superior ophthalmic vein thrombosis due to severe superior ophthalmic vein enlargement in a patient with graves ophthalmopathy.

We report a patient with branch retinal vein occlusion (BRVO) accompanied by superior ophthalmic vein (SOV) thrombosis resulting from severe SOV enlargement in a patient with Graves ophthalmopathy (GO). A 78-year-old woman diagnosed with BRVO presented with reduced vision. She had a more than 20-year history of unilateral GO. Fluorescein angiography and spectralis optical coherence tomography revealed BRVO with cystoid macular edema. Approximately 5 months later, she complained of advanced left proptosis. A computed tomography scan at that time revealed dilated SOV with high internal attenuation due to SOV thrombosis of the left orbit. Because of the uncertain onset of SOV thrombosis and minimal signs of acute orbital congestion, we prescribed prophylactic daily aspirin to improve blood flow rather than a heparin-based treatment. In addition, she was treated with lubricants for exposure keratopathy and a dorzolamide/timolol eyedrops to prevent increases in intraocular pressure. This is the first clinical report of BRVO accompanied by SOV thrombosis due to SOV enlargement in chronic severe GO. It should be recognized that SOV thrombosis can lead to an increase in proptosis even in chronic GO.

Single pretreatment of remifentanil may reduce pain after propofol and rocuronium injection in rapid sequence induction.

BACKGROUND: We designed this double-blind, placebo-controlled study to compare the efficacy of remifentanil in reducing the pain of both propofol and rocuronium injection during rapid-sequence induction. METHODS: Ninety-five patients, scheduled for elective surgery under general anesthesia, were divided into 3 groups: saline (Group S, n = 31), remifentanil 1 µg/kg (Group R, n = 32), and lidocaine 1.5 mg/kg (Group L, n = 32) were administered after tourniquet application. The occlusion was released after 1 min and 5 ml of 1% propofol was injected over 10 s. Pain on propofol injection was evaluated by a 10-point verbal numeric rating scale (VNRS). The rest of the induction dose of propofol and 1 mg/kg of rocuronium, were injected. Pain on rocuronium injection was evaluated by a four-point score (FPS). RESULTS: THE VNRS OF PROPOFOL INJECTION WAS AS FOLLOWS: R (0.78) = L (1.34) < S (4.26). The incidence of withdrawal response due to rocuronium was as follows: R (6.3%) < L (53.1%) < S (83.9%). The FPS of rocuronium injection was as follows: R (0.81) < L (1.78) < S (2.93). CONCLUSIONS: Pretreatment with a bolus of remifentanil was effective in simultaneously reducing injection pain of propofol and rocuronium. In addition, remifentanil pretreatment was more effective in suppression of withdrawal response by rocuronium than lidocaine.