Epitaxial strain imposed in complex oxide thin films by heteroepitaxy is recognized as a powerful tool for identifying new properties and exploring the vast potential of materials performance. A particular example is LaCoO(3), a zero spin, nonmagnetic material in the bulk, whose strong ferromagnetism in a thin film remains enigmatic despite a decade of intense research. Here, we use scanning transmission electron microscopy complemented by X-ray and optical spectroscopy to study LaCoO(3) epitaxial thin films under different strain states. We observed an unconventional strain relaxation behavior resulting in stripe-like, lattice modulated patterns, which did not involve uncontrolled misfit dislocations or other defects. The modulation entails the formation of ferromagnetically ordered sheets comprising intermediate or high spin Co(3+), thus offering an unambiguous description for the exotic magnetism found in epitaxially strained LaCoO(3) films. This observation provides a novel route to tailoring the electronic and magnetic properties of functional oxide heterostructures.

BackgroundThe aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors.MethodsThis cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated.ResultsAfter exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area.ConclusionsA decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.

Background: Suicide rates have recently been decreasing on average among OECD countries, but increasing trends have been detected in South Korea, particularly since the 1997 economic crisis. There have been no detailed analyses about the changes of the suicide rates over time periods in Korea. We examined trends in both absolute and proportional suicide rates over the time period of economic development, crisis, and recovery (1986 -2005) as well as in birth cohorts from 1924 to 1978.

BackgroundA regular menstrual cycle is an important indicator of a healthy reproductive system. Previous studies reported obesity, stress, and smoking as the factors that are associated with irregular menstruation and early menopause. However, the integrative effects of these modifiable risk factors have not been fully understood. This study aimed to investigate the modifiable risk factors of menstrual cycle irregularity and premature menopause, as well as their individual and combined effects among adult women in Korea.MethodThis study selected adult women aged 19 years and above who had been included in the 2007–2014 Korean National Health and Nutrition Examination Survey. We used a separate dataset to analyze the risk factors of menstrual cycle irregularity and menopause (pre- and postmenopausal women: n = 4788 and n = 10,697, respectively). Univariate and multiple logistic regression analyses were conducted to evaluate the effects of smoking, drinking, obesity, and perceived level of stress on the menstrual cycle and menopause. Both logit and linear models were used in the analyses of the association between smoking and menopausal age. Equivalized household income, marital status, and educational level were considered as covariates. The modifiable risk factor scores were also calculated to integrate the effect of smoking, drinking, and obesity in the analysis.ResultResults showed that smoking status, pack-year, obesity, and perceived level of stress were significantly associated with irregular menstruation among premenopausal women. Especially, women demonstrating > 3 modifiable risk factor scores had 1.7 times higher risk of having irregular menstruation than those who had a 0 score. Meanwhile, early initiation of smoking (≤19 years) and high pack-year (≥5) were also significantly associated with premature menopause among postmenopausal women.ConclusionThis study demonstrated that modifiable risk factors, such as smoking, obesity, and stress, were significantly associated with menstrual cycle irregularity. Lifetime smoking was also correlated with early menopause. Our results suggested that healthier lifestyle practices, including, cessation of smoking, weight control, and stress management, were important factors in improving the reproductive health of women throughout life.

A new critical-current-by-design paradigm is presented. It aims at predicting the optimal defect landscape in superconductors for targeted applications by elucidating the vortex dynamics responsible for the bulk critical current. To this end, critical current measurements on commercial high-temperature superconductors are combined with large-scale time-dependent Ginzburg-Landau simulations of vortex dynamics.

Interfaces between correlated complex oxides are promising avenues to realize new forms of magnetism that arise as a result of charge transfer, proximity effects, and locally broken symmetries. We report on the discovery of a noncollinear magnetic structure in superlattices of the ferromagnetic metallic oxide La 2=3 Sr 1=3 MnO 3 (LSMO) and the correlated metal LaNiO 3 (LNO). The exchange interaction between LSMO layers is mediated by the intervening LNO, such that the angle between the magnetization of neighboring LSMO layers varies in an oscillatory manner with the thickness of the LNO layer. The magnetic field, temperature, and spacer thickness dependence of the noncollinear structure are inconsistent with the bilinear and biquadratic interactions that are used to model the magnetic structure in conventional metallic multilayers. A model that couples the LSMO layers to a helical spin state within the LNO fits the observed behavior. We propose that the spin-helix results from the interaction between a spatially varying spin susceptibility within the LNO and interfacial charge transfer that creates localized Ni 2þ states. Our work suggests a new approach to engineering noncollinear spin textures in metallic oxide heterostructures. Oxide interfaces have attracted considerable interest in recent years, as the reconstruction of charge, orbital, and spin states on the nanometer scale gives rise to novel phenomena that range from interfacial superconductivity to multiferroic behavior [1]. In this context, interfaces between oxides that are metallic in the bulk are particularly intriguing, as the large electronic compressibility, the relatively large bare dielectric constant, and band misalignment can work in concert to create significant interfacial charge transfer over a region of several unit cells [2][3][4]. In oxides derived from correlated Mott insulators, this effect can manifest latent electronic and magnetic instabilities, leading to new collective states near the interface.While a large body of work has emerged on heterostructures that incorporate insulating complex oxides [5][6][7][8][9][10][11][12][13][14][15][16], those created exclusively with metallic oxide constituents have been far less explored [17][18][19], despite the technological importance and wide range of behaviors observed in multilayers of conventional metals. The discovery of giant magnetoresistance (GMR) [20,21] and the subsequent demonstration of a tunable collinear exchange coupling in such structures [22] opened new pathways to high-density magnetic data storage. Multilayers with noncollinear magnetic ordering, however, are rarer, as such structures require a delicate balance between exchange energies, which only occurs under special circumstances [23][24][25][26][27]. Engineering robust noncollinear magnetic states at oxide interfaces presents new opportunities to explore novel effects, such * jasonhoffman@fas.harvard.edu; Present address:

The aims of this study were to demonstrate the trends in seropositivity and the eradication therapy rate for Helicobacter pylori (H. pylori) over an 18-year period in an asymptomatic Korean population and to explore the factors associated with H. pylori seropositivity and its eradication therapy. In total, 23,770 subjects (aged 17–97 years) from a health examination center participated in this cross-sectional study from January 2016 to June 2017. Questionnaires that included questions about the participants’ H. pylori eradication therapy history were collected, and anti-H. pylori IgG antibodies were measured. Among the eligible subjects, the seroprevalence of H. pylori infection was 41.5%. The H. pylori eradication therapy rate increased continuously from 2005 (13.9%) to 2011 (19.3%) and then increased again until the first half of 2017 (23.5%) (P < 0.001). After exclusion of subjects with a history of gastric surgery, gastric cancer, H. pylori eradication therapy, or gastric symptoms, H. pylori seropositivity was 43.9% in 16,885 subjects, which was significantly lower than the seropositivities in 1998 (66.9%), 2005 (59.6%), and 2011 (54.4%). The risk factors associated with H. pylori seropositivity according to multivariable analysis were male sex (odds ratio (OR) 1.34, 95% confidence interval (CI): 1.23–1.46), medium educational level (OR 1.17, 95% CI: 1.05–1.31), medium household income level (OR 1.10, 95% CI: 1.03–1.19), and age of 60–69 years (OR 8.78, 95% CI: 6.41–11.85). The observed downward trend in H. pylori seroprevalence and increase in H. pylori eradication over the 18-year period will affect upper gastrointestinal disorders in South Korea.

BackgroundTo compare the effects of endovascular coiling and neurosurgical clipping in patients with unruptured intracranial aneurysm.MethodsSixteen electronic databases were searched for articles published between 1950 and July 2010 to compare clinical outcomes of clipping and coiling. Researchers reviewed all searched articles and extracted data independently. The quality of studies and evidence were evaluated using MINORS and GRADEprofiler, respectively. The odds ratio (OR) was calculated using the inverse variance meta-analysis method for each study outcome. To assess heterogeneity of ORs across cohorts, Cochran’s Q statistic and I2 were used.ResultsOf 4160 studies, 24 were identified (n  =  31865). Clipping resulted in significantly higher disability using the Glasgow Outcome Scale (OR, 2.38; 95% CI, 1.33–4.26) and Modified Rankin Scale (OR, 2.83; 95% CI, 1.42–5.63) when compared with coiling. ORs for complications were also higher with clipping (ORs for neurological and cardiac complications were 1.94 with a 95% confidence interval [CI] of 1.09–3.47 and 2.51 with a 95% CI of 1.15–5.50). Clipping resulted in significantly greater disability in the short term (≤6 m)(OR on the Glasgow Outcome Scale, 2.72; 95% CI, 1.16–6.34), but not in the long term (>6 m)(OR for Glasgow Outcome Scale, 2.12; 95% CI, 0.93–4.84).ConclusionsCoiling was a better procedure for treatment of unruptured intracranial aneurysm in terms of disability, complications, especially in the short term. Because of the limitations of the reviewed studies, further studies are required to support the present results.