Prognostic impact of MitraScore in elderly Asian patients with heart failure: sub-analysis of FRAGILE-HF.

AIMS: MitraScore is a novel, simple, and manually calculatable risk score developed as a prognostic model for patients undergoing transcatheter edge-to-edge repair (TEER) for mitral regurgitation. As its components are considered prognostic in heart failure (HF), we aimed to investigate the usefulness of the MitraScore in HF patients. METHODS AND RESULTS: We calculated MitraScore for 1100 elderly patients (>65 years old) hospitalized for HF in the prospective multicentre FRAGILE-HF study and compared its prognostic ability with other simple risk scores. The primary endpoint was all-cause deaths, and the secondary endpoints were the composite of all-cause deaths and HF rehospitalization and cardiovascular deaths. Overall, the mean age of 1100 patients was 80 ± 8 years, and 58% were men. The mean MitraScore was 3.2 ± 1.4, with a median of 3 (interquartile range: 2-4). A total of 326 (29.6%), 571 (51.9%), and 203 (18.5%) patients were classified into low-, moderate-, and high-risk groups based on the MitraScore, respectively. During a follow-up of 2 years, 226 all-cause deaths, 478 composite endpoints, and 183 cardiovascular deaths were observed. MitraScore successfully stratified patients for all endpoints in the Kaplan-Meier analysis (P < 0.001 for all). In multivariate analyses, MitraScore was significantly associated with all endpoints after covariate adjustments [adjusted hazard ratio (HR) (95% confidence interval): 1.22 (1.10-1.36), P < 0.001 for all-cause deaths; adjusted HR 1.17 (1.09-1.26), P < 0.001 for combined endpoints; and adjusted HR 1.24 (1.10-1.39), P < 0.001 for cardiovascular deaths]. The Hosmer-Lemeshow plot showed good calibration for all endpoints. The net reclassification improvement (NRI) analyses revealed that the MitraScore performed significantly better than other manually calculatable risk scores of HF: the GWTG-HF risk score, the BIOSTAT compact model, the AHEAD score, the AHEAD-U score, and the HANBAH score for all-cause and cardiovascular deaths, with respective continuous NRIs of 0.20, 0.22, 0.39, 0.39, and 0.29 for all-cause mortality (all P-values < 0.01) and 0.20, 0.22, 0.42, 0.40, and 0.29 for cardiovascular mortality (all P-values < 0.02). CONCLUSIONS: MitraScore developed for patients undergoing TEER also showed strong discriminative power in HF patients. MitraScore was superior to other manually calculable simple risk scores and might be a good choice for risk assessment in clinical practice for patients receiving TEER and those with HF.

A Case of Low-Grade Appendiceal Mucinous Neoplasm That Led to Surgery After 12 Years of No Treatment.

Low-grade appendiceal mucinous neoplasm (LAMN) is a relatively rare, non-invasive appendiceal tumor. We experienced a case of LAMN that led to surgery after 12 years of no treatment. Until now, LAMN has been reported to progress more slowly than other tumors, but there have been no reports of long-term follow-up of appendiceal tumors without treatment. Although the tumor had grown over the course of 12 years, there was no mixing or migration of other histological types, and it did not lead to pseudomyxoma peritonei. As this course is considered to be relatively rare, we report it along with a literature review.

Prediction of extensive necrotic change in acute gangrenous cholecystitis.

PURPOSE: Gangrenous cholecystitis (GC) is a severe type of acute cholecystitis that implies higher mortality and morbidity rates than uncomplicated cholecystitis. The characteristics of GC are various for each case. However, preoperative predictors of GC with extensive necrotic change have not been investigated well. METHODS: A total of 239 patients who were pathologically diagnosed with GC underwent laparoscopic cholecystectomy at our hospital between January 2013 and December 2021. Of these, 135 patients were included in this study and were subdivided into the extensive necrosis group (patients with necrotic change extending to the neck of the gallbladder, n = 18) and the control group (patients with necrotic change limited to the fundus or body, not extending to the neck, n = 117) according to each operation video. Patient characteristics and perioperative factors predicting extensive necrotic change were investigated. RESULTS: Pericholecystic fat stranding (83.3 vs. 53.8%, p = 0.018) and absence of wall enhancement on preoperative CT images (50.0 vs. 24.7%, p = 0.026) were significantly associated with extensive necrosis. Seven of 18 patients in the extensive necrosis group showed necrotic changes beyond the infundibulum. The absence of wall enhancement on preoperative CT images (71.4 vs. 28.8%, p = 0.018) was significantly associated with necrotic changes beyond the infundibulum. CONCLUSIONS: Pericholecystic fat stranding and absence of wall enhancement on preoperative enhanced CT are predictors of extensive necrotic change in patients with GC. In addition, the absence of wall enhancement also predicts the presence of necrotic changes beyond the infundibulum.

Prevalence and prognostic impact of cognitive frailty in elderly patients with heart failure: sub-analysis of FRAGILE-HF.

AIMS: Although evidence suggests that cognitive decline and physical frailty in elderly patients with heart failure (HF) are associated with prognosis, the impact of concurrent physical frailty and cognitive impairment, that is, cognitive frailty, on prognosis has yet to be fully investigated. The current study sought to investigate the prevalence and prognostic impact of cognitive frailty in elderly patients with HF. METHODS AND RESULTS: This study is a sub-analysis of FRAGILE-HF, a prospective multicentre observational study involving patients aged ≥65 years hospitalized for HF. The Fried criteria and Mini-Cog were used to diagnose physical frailty and cognitive impairment, respectively. The association between cognitive frailty and the combined endpoint of mortality and HF rehospitalization within 1 year was then evaluated. Among the 1332 patients identified, 1215 who could be assessed using Mini-Cog and the Fried criteria were included in this study. Among those included, 279 patients (23.0%) had cognitive frailty. During the follow-up 1 year after discharge, 398 combined events were observed. Moreover, cognitive frailty was determined to be associated with a higher incidence of combined events (log-rank: P = 0.0146). This association was retained even after adjusting for other prognostic factors (hazard ratio: 1.55, 95% confidence interval: 1.13-2.13). Furthermore, a sensitivity analysis using grip strength, short physical performance battery, and gait speed to determine physical frailty instead of the Fried criteria showed similar results. CONCLUSIONS: This cohort study found that 23% of elderly patients with HF had cognitive frailty, which was associated with a 1.55-fold greater risk for combined events within 1 year compared with patients without cognitive frailty.

Pancreaticobiliary maljunction without biliary dilatation in pediatric patients.

PURPOSE: Pancreaticobiliary maljunction (PBM) without biliary dilatation is a condition in which dilatation of the bile duct is not seen in patients with PBM. Recently, the Japanese Study Group on Pancreaticobiliary Maljunction (JSGPM) published new diagnostic criteria for PBM. In these criteria, biliary dilatation is defined according to the standard diameter at each age. We reviewed cases of pediatric patients with PBM without biliary dilatation. METHODS: From 1992 to 2019, 134 patients with PBM were treated in our institution. Among these, 7 patients were retrospectively diagnosed with PBM without biliary dilatation. The clinical information was retrospectively assessed in these patients. RESULTS: Of the seven patients, six were female. All patients had symptoms similar to those of patients with congenital biliary dilatation. In all seven patients, the diagnosis of PBM was made before definitive surgery. Six patients had type B PBM, and one had type D PBM. All patients underwent extrahepatic bile duct resection and hepaticojejunostomy, and their symptoms resolved. One patient experienced postoperative complications of anastomotic leakage followed by anastomotic stricture. CONCLUSION: The present report revealed important clinical features of this entity. However, there are still some issues that need to be discussed, and further research is needed.

Safety and Feasibility of Laparoscopic Transabdominal Preperitoneal Hernia Repair for Octo- and Nonagenarians.

Background: The feasibility of laparoscopic hernia repair in octo- and nonagenarians has not been investigated in detail. The aim of this retrospective study was to evaluate the safety and feasibility of laparoscopic hernia repair in octo- and nonagenarians. Methods: This study included 607 patients who underwent transabdominal preperitoneal laparoscopic hernia repair at our hospital between April 2014 and October 2020. Patients were divided into an over 80 group (112 patients aged 80 years and older) and a control group (495 patients younger than 80 years). The clinical outcomes were compared between the groups. In addition, among patients aged 80 years and older, those who underwent elective laparoscopic hernia repair (laparoscopic group: 111 patients) were compared with patients who underwent elective open hernia repair during the same study period (open group: 79 patients). Results: The number of patients who underwent bilateral hernia repair was significantly larger in the over 80 group (26.7% versus 11.7%, P < .001). The incidence of postoperative complications was not significantly different between the over 80 group and the control group. Compared with open group, the number of patients who underwent bilateral hernia repair was significantly larger in the laparoscopic group (27.0% versus 2.5%, P < .001). The incidence of postoperative complications (2.7% versus 10.1%) and the incidence of readmission (0.9% versus 6.3%) were significantly greater in the open group. Conclusions: Laparoscopic hernia repair in octo- and nonagenarian patients yields safe and noninferior outcomes. Laparoscopic hernia repair in octo- and nonagenarian patients is considered more suitable for detecting and repairing contralateral hernias simultaneously.

Impact of physical performance on exercise capacity in older patients with heart failure with reduced and preserved ejection fraction.

BACKGROUND: Low physical performance may contribute to reduced exercise capacity in older patients with heart failure (HF). We sought to identify the determinants of exercise capacity out of a plethora of background factors, including measures of physical performance. METHODS: We performed a post-hoc analysis of a cohort study that included 1205 consecutive older (age ≥ 65 years) hospitalized patients (the median age, 80 years; 57.4% males). RESULTS: Low physical performance, defined as ≤1.0 m/s for gait speed, ≥12 s for the 5-time chair stand test, or ≤ 9 points for the Short Physical Performance Battery in both sexes, was seen in 83.9% of the cohort. Multivariate regression analysis revealed that each parameter of physical performance (i.e., gait speed, chair stand test, and balance test) was identified as an independent determinant of lower exercise capacity assessed using the 6-min walking distance. In a logistic regression model, low physical performance predicted short (<300 m) 6-min walking distance (adjusted odds ratio 10.28, 95% CI 6.01-17.60, p < 0.001). No interaction was detected between patients with preserved and reduced ejection fraction. CONCLUSIONS: Low physical performance was prevalent and independently associated with exercise capacity in older patients with HF, irrespective of preserved or reduced ejection fraction.

Validity and Utility of the Questionnaire-based FRAIL Scale in Older Patients with Heart Failure: Findings from the FRAGILE-HF.

OBJECTIVES: We investigated whether the FRAIL scale questionnaire is consistent with the Fried criteria, predicts all-cause mortality, and reflects physical dysfunction in patients with heart failure (HF). DESIGN: Secondary analysis of FRAGILE-HF, a cohort study that enrolled participants from 2016 to 2018 and followed-up for 1-year of discharge. SETTING AND PARTICIPANTS: A prospective multicenter cohort study in which 15 hospitals in Japan (8 university hospitals and 7 nonuniversity teaching hospitals) participated. We prospectively enrolled 1332 consecutive hospitalized patients ≥65 years old with HF and analyzed 1028 patients after excluding 304 patients with missing data on the FRAIL scale. METHODS: The FRAIL scale, the Fried model, and physical function were measured before discharge. The endpoint was all-cause mortality. RESULTS: According to the FRAIL scale, 459 (44.6%) and 491 (47.8%) were classified as frail and prefrail, respectively. The Kappa coefficient between the FRAIL scale and the Fried criteria were 0.39 [95% confidence interval (CI) 0.34-0.44; P < .001]. The area under the receiver-operating characteristic curves for frailty diagnosed by the Fried criteria of the FRAIL scale was 0.74 (95% CI 0.71-0.76; P < .001). A total of 118 deaths occurred during 1 year of follow-up. After adjusting for the MAGGIC risk score and log-BNP, The FRAIL scale predicted all-cause mortality (hazard ratio 1.17; 95% CI 1.01-1.36; P = .035). The FRAIL scale was also associated with various physical dysfunctions that correlated with poor prognosis. CONCLUSIONS AND IMPLICATIONS: The FRAIL scale had moderate consistency with the Fried criteria, predicted all-cause mortality, and reflected clinically important physical dysfunctions.

Obstructive Fecalomas in an Infant Treated with Successful Endoscopic Disimpaction.

A fecaloma is a mass of accumulated feces with a consistency much harder than that of a fecal impaction. It is most frequently observed in the rectum and sigmoid area, and associated complications include colonic obstruction, ulceration, bleeding, and perforation. A one-year-old, previously healthy boy with no history of chronic constipation was admitted because of vomiting and abdominal distension. An abdominal computed tomography scan showed small and large bowel distension due to multiple obstructive fecalomas in the transverse colon. As the fecalomas could not be resolved by laxatives, enemas, or colonic lavage, endoscopic disimpaction under general anesthesia was attempted. Repeatedly shaving the fecalomas with biopsy forceps finally resulted in gradual fragmentation with subsequent passage. Gastrointestinal food allergy was later suggested as the cause because eosinophilic infiltration was found in a biopsy specimen of the colon wall. Endoscopic disimpaction is an effective treatment approach for addressing fecalomas to avoid more invasive surgical intervention.

Impact of sarcopenia on prognosis in patients with heart failure with reduced and preserved ejection fraction.

AIMS: Sarcopenia, one of the extracardiac factors for reduced functional capacity and poor outcome in heart failure (HF), may act differently between HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). We sought to investigate the impact of sarcopenia on mortality in HFpEF and HFrEF. METHODS AND RESULTS: We performed a post hoc analysis of a multicentre prospective cohort study, including 942 consecutive older (age ≥65 years) hospitalized patients: 475 with HFpEF (ejection fraction ≥45%, age 81 ± 7 years, 48.8% men) and 467 with HFrEF (ejection fraction <45%, age 78 ± 8 years, 68.1% men). Sarcopenia was diagnosed according to the international criteria incorporating muscle strength (handgrip strength), physical performance (gait speed), and skeletal muscle mass (appendicular skeletal mass). The HFpEF group consisted of fewer patients with low appendicular skeletal muscle mass index measured using bioelectrical impedance analysis [<7.0 kg/m2 (men) and <5.7 (women); 22.1% vs. 31.0%, P = 0.003], and more patients with low handgrip strength [<26 kg (men) and <18 (women); 67.8% vs. 55.5%, P < 0.001], and slow gait speed [<0.8 m/s (both sexes); 54.5% vs. 41.1%, P < 0.001] than the HFrEF group, resulting in a similar sarcopenia prevalence in the two groups (18.1% vs. 21.6%, P = 0.191). Sarcopenia was an independent predictor of 1-year mortality in both HFpEF and HFrEF [hazard ratio (95% confidence interval) 2.42 (1.36-4.32), P = 0.003 in HFpEF and 2.02 (1.08-3.75), P = 0.027 in HFrEF; P for interaction = 0.666] after adjustment for other predictors. CONCLUSIONS: In older patients with HF, sarcopenia contributes to mortality similarly in HFpEF and HFrEF.

A 5-year-old boy with acute neurological disorder from anteflexion-induced cervical cord compression after tracheal surgery: Radiological findings similar to Hirayama disease.

Constant neck flexion has been considered crucial to reducing anastomotic tension after tracheal resection. However, in rare cases, anteflexion can cause cervical cord damage, leading to acute neurological disorders such as tetraplegia. Here, we report a case of 5-year-old boy presenting with acute neurological disorder triggered by a chin-to-chest position over 4 days of deep sedation after cricotracheal resection. The radiological findings would suggest a mechanism similar to Hirayama disease, in which a shift of the dura leads to chronic muscular weakness and atrophy in young populations.

Nano-imprinting potential of magnetic FeCo-based metallic glass.

Fabrication of magnetic nanostructures at low cost is strongly desired for applications such as sensors, actuators, magnetic memory, etc. In conventional nano-patterning techniques, the magnetic field of a magnetic material interferes with the patterning process, making nano-patterning challenging. Here, we report on the low cost patterning potential of FeCo-based magnetic metallic glass using a nano-imprinting technique. We show that out of a large number of magnetic metallic glasses, Fe40Co35P10C10B5 glassy alloy exhibits high saturation magnetic flux density (B s  âˆ¼ 1.24 T), a large super-cooled liquid temperature range (ΔT x  âˆ¼ 49 °C), and a relatively low glass transition temperature (T g  âˆ¼ 430 °C) with good thermal stability. The quasi-static viscosity (∼108 Pa.s at a heating rate of ∼40 °C min-1) in ΔT x , which is one of the most important parameters for nano-imprinting, is lowest among the reported magnetic metallic glasses. The deformability of this magnetic alloy is similar to the well-known non-magnetic metallic glasses, which can be patterned to a few tens of nanometers. Crystallization of Fe40Co35P10C10B5 glassy alloy leads to the precipitation of a high B s FeCo phase that may exhibit high magnetocrystalline anisotropy. Based on detailed investigations of structural, thermal, and magnetic behavior, along with imprinting experiments, we show that the Fe40Co35P10C10B5 glassy alloy is the most desirable material for making various nano-patterns with tailorable magnetic properties.

Third-Order Nonlinear Optical Properties of One-Dimensional Quinoidal Oligothiophene Derivatives Involving Phenoxyl Groups.

The diradical characters (y) and third-order nonlinear optical (NLO) properties of open-shell quinoidal oligothiophene derivatives with phenoxyl groups, and the corresponding reduced (hydrogenated)-state oligomers, are investigated by using the broken-symmetry density functional theory method. The oxidized (dehydrogenated) states are predicted to have an open-shell singlet ground state and their y values increase with the number of units. Static second hyperpolarizabilities (γ) of the open-shell oligomers with intermediate y are shown to be enhanced significantly compared with those of the closed-shell analogues. Furthermore, owing to the effective diradical distances, the γ values of open-shell oligomers are found to exceed that of s-indaceno[1,2,3-cd;5,6,7-c'd']diphenalene, which is known as an organic molecule with the largest two-photon absorption cross-section in this size of the pure hydrocarbons. This feature extends the range of efficient open-shell third-order NLO materials to a novel class of one-dimensional conjugated oligomers with redox-based high tunability of third-order NLO properties.

Structural Inheritance and Redox Performance of Nanoporous Electrodes from Nanocrystalline Fe85.2B10-14P0-4Cu0.8 Alloys.

Nanoporous electrodes have been fabricated by selectively dissolving the less noble α-Fe crystalline phase from nanocrystalline Fe85.2B14-xPxCu0.8 alloys (x= 0, 2, 4 at.%). The preferential dissolution is triggered by the weaker electrochemical stability of α-Fe nanocrystals than amorphous phase. The final nanoporous structure is mainly composed of amorphous residual phase and minor undissolved α-Fe crystals and can be predicted from initial microstructure of nanocrystalline precursor alloys. The structural inheritance is proved by the similarity of the size and outlines between nanopores formed after dealloying in 0.1 M H2SO4 and α-Fe nanocrystals precipitated after annealing of amorphous Fe85.2B14-xPxCu0.8 (x = 0, 2, 4 at.%) alloys. The Redox peak current density of the nanoporous electrodes obtained from nanocrystalline Fe85.2B10P4Cu0.8 alloys is more than one order higher than those of Fe plate electrode and its counterpart nanocrystalline alloys due to the large surface area and nearly-amorphous nature of ligaments.

Diradical Character Tuning for the Third-Order Nonlinear Optical Properties of Quinoidal Oligothiophenes by Introducing Thiophene-S,S-dioxide Rings.

To create a design guideline for efficient third-order nonlinear optical (NLO) molecules, the chain-length (n) dependences of the diradical character y and the longitudinal second hyperpolarizability γ of quinoidal oligothiophenes (QTs), from monomers to octamers, involving thiophene-S,S-dioxide rings are investigated by using the density functional theory method. It turns out that the diradical character of the modified QTs is reduced as compared to those of the pristine QTs. By introducing an appropriate number of oxidized rings into the QT framework, intermediate y values can be achieved even in the systems with large values of n, in which the pristine QTs are predicted to have pure diradical character. Such intermediate diradical oligomers are shown to exhibit enhanced γ values as compared to the pristine QTs with the same value for n. From the calculation results, the introduction of the optimal number of thiophene-S,S-dioxide rings is predicted to be an efficient chemical modification for optimizing the third-order NLO properties of open-shell QTs through tuning the diradical characters.

Artificially produced rare-earth free cosmic magnet.

Chemically ordered hard magnetic L10-FeNi phase of higher grade than cosmic meteorites is produced artificially. Present alloy design shortens the formation time from hundreds of millions of years for natural meteorites to less than 300 hours. Electron diffraction detects four-fold 110 superlattice reflections and a high chemical order parameter (S 0.8) for the developed L10-FeNi phase. The magnetic field of more than 3.5 kOe is required for the switching of magnetization. Experimental results along with computer simulation suggest that the ordered phase is formed due to three factors related to the amorphous state: high diffusion rates of the constituent elements at lower temperatures when crystallizing, a large driving force for precipitation of the L10 phase, and the possible presence of L10 clusters. Present results can resolve mineral exhaustion issues in the development of next-generation hard magnetic materials because the alloys are free from rare-earth elements, and the technique is well suited for mass production.

Metallic glass thin films for potential biomedical applications.

We introduce metallic glass thin films (TiCuNi) as biocompatible materials for biomedical applications. TiCuNi metallic glass thin films were deposited on the Si substrate and their structural, surface, and mechanical properties were investigated. The fabricated films showed good biocompatibility upon exposure to muscle cells. Also, they exhibited an average roughness of <0.2 nm, high wear resistance, and high mechanical properties (hardness ∼6.9 GPa and reduced modulus ∼130 GPa). Top surface of the TiCuNi films was shown to be free from Ni and mainly composed of a thin titanium oxide layer, which resulted in the high surface biocompatibility. In particular, there was no cytotoxicity effect of metallic glass films on the C2C12 myoblasts and the cells were able to proliferate well on these substrates. Low cost, viscoelastic behavior, patternability, high electrical conductivity, and the capability to coat various materials (e.g., nonbiocompatible materials) make TiCuNi as an attractive material for biomedical applications.

Soluble Fms-like tyrosine kinase 1 is a novel predictor of brain natriuretic peptide elevation.

Soluble fms-like tyrosine kinase 1 (sFlt-1) is an endogenous inhibitor of vascular endothelial growth factor, which is involved in cardiovascular remodeling and atherosclerosis development. To examine the predictive role of sFlt-1 levels in patients with asymptomatic heart failure, we measured circulating sFlt-1 in patients with or without coronary artery disease (CAD). We analyzed 88 Japanese patients with CAD or patients at high risk for atherosclerosis and who were undergoing total risk management for cardiovascular disease prevention. Circulating sFlt-1 levels correlated with the increase in plasma brain natriuretic peptide levels (ΔBNP) from baseline to the observed levels 5 years later in CAD patients, patients with previous myocardial infarction, and men. ΔBNP levels correlated with sFlt-1 levels in the high-sFlt-1 patients with CAD (r = 0.511, P < 0.01). In all patients, end-systolic volume index (ΔESVI) increased in correlation with a decrease in left ventricular ejection fraction (ΔEF) in the long-term observation, independent of their history of myocardial infarction (ΔESVI = 2.5 mL/m(2) increase/year). Baseline level of sFlt-1 was independent of ΔESVI or ΔEF. The present 5-year observational study demonstrated that high sFlt-1 levels predicted moderate increases in BNP levels in CAD patients. Moreover, ΔBNP was correlated with ΔESVI/year in CAD patients with high-sFlt-1 levels. These data suggest that high sFlt-1 levels may be an effective biomarker to predict the progression of heart failure in patients with CAD.

Magnetization reversal in a preferred oriented (111) L1(0) FePt grown on a soft magnetic metallic glass for tilted magnetic recording.

L1(0) FePt is an important material for the fabrication of high density perpendicular recording media, but the ultrahigh coercivity of L1(0) FePt restricts its use. Tilting of the magnetic easy axis and the introduction of a soft magnetic underlayer can solve this problem. However, high temperature processing and the requirement of epitaxial growth conditions for obtaining an L1(0) FePt phase are the main hurdles to be overcome. Here, we introduce a bilayered magnetic structure ((111) L1(0) FePt/glassy Fe(71)Nb(4)Hf(3)Y(2)B(20)/SiO(2)/Si) in which the magnetic easy axis of L1(0) FePt is tilted by ~36° from the film plane and epitaxial growth conditions are not required. The soft magnetic underlayer not only promotes the growth of L1(0) FePt with the preferred orientation but also provides an easy cost-effective micro/nanopatterning of recording bits. A detailed magnetic characterization of the bilayered structure in which the thickness of (111) L1(0) FePt with the soft magnetic Fe(71)Nb(4)Hf(3)Y(2)B(20) glassy underlayer varied from 5 to 60 nm is carried out in an effort to understand the magnetization switching mechanism. The magnetization switching behavior is almost the same for bilayered structures in which FePt layer thickness is >10 nm (greater than the domain wall thickness of FePt). For FePt film ~10 nm thick, magnetization reversal takes place in a very narrow field range. Magnetization reversal first takes place in the soft magnetic underlayer. On further increase in the reverse magnetic field, the domain wall in the soft magnetic layer compresses at the interface of the hard and soft layers. Once the domain wall energy becomes sufficiently large to overcome the nucleation energy of the domain wall in L1(0) FePt, the magnetization of the whole bilayer is reversed. This process takes place quickly because the domain walls in the hard layer do not need to move, and the formation of a narrower domain wall may not be favorable energetically. Our results showed that the present bilayered structure is very promising for the fabrication of tilted bit-patterned magnetic recording media.

Micromirror with large-tilting angle using Fe-based metallic glass.

For enhancing the micromirror properties like tilting angle and stability during actuation, Fe-based metallic glass (MG) was applied for torsion bar material. A micromirror with mirror-plate diameter of 900 µm and torsion bar dimensions length 250 µm, width 30 µm and thickness 2.5 µm was chosen for the tilting angle tests, which were performed by permanent magnets and electromagnet setup. An extremely large tilting angle of over -270° was obtained from an activation test by permanent magnet that has approximately 0.2 T of magnetic strength. A large mechanical tilting angle of over -70° was obtained by applying approximately 1.1 mT to the mirror when 93 mAwas applied to solenoid setup. The large-tilting angle of the micromirror is due to the torsion bar, which was fabricated with Fe-based MG thin film that has large elastic strain limit, fracture toughness, and excellent magnetic property.