164 research outputs found

    Monovacancy-induced magnetism in graphene bilayers

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    Vacancy-induced magnetism in graphene bilayers is investigated using spin-polarized density functional theory calculations. One of two graphene layers has a monovacancy. Two atomic configurations for bilayers are considered with respect to the position of the monovacancy. We find that spin magnetic moments localized at the vacancy site decreases by ~10 % for our two configurations, compared with the graphene monolayer with a monovacancy. The reduction of the spin magnetic moment in the graphene bilayers is attributed to the interlayer charge transfer from the adjacent layer to the layer with the monovacancy, compensating for spin magnetic moments originating from quasilocalized defect state.Comment: 14 pages, 1 table and 4 figure

    Paired gap states in a semiconducting carbon nanotube: Deep and shallow levels

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    Several paired, localized gap states were observed in semiconducting single-wall carbon nanotubes using spatially resolved scanning tunneling spectroscopy. A pair of gap states is found far from the band edges, forming deep levels, while the other pair is located near the band edges, forming shallow levels. With the help of a first-principles study, the former is explained by a vacancy-adatom complex while the latter is explained by a pentagon-heptagon structure. Our experimental observation indicates that the presence of the gap states provides a means to perform local band-gap engineering as well as doping without impurity substitution.open433

    Recurrent Streptococcus Pneumoniae Meningoencephalitis in a Patient With a Transethmoidal eningoencephalocele

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    We report a case of recurrent Streptococcus Pneumoniae meningoencephalitis with a transethmoidal meningoencephalocele (TEME) but without cerebrospinal fluid (CSF) leakage

    Pregnancy-related knowledge, risk perception, and reproductive decision making of women with epilepsy in Korea

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    AbstractPurposeTo determine the influence of pregnancy-related knowledge and the risk perception on reproductive decision making in women with epilepsy.MethodsWe enrolled women with epilepsy, who were of reproductive age and were considering having children in the future. A questionnaire was used to assess the level of pregnancy-related knowledge, perception of the offspring's risk for developing epilepsy or for having a congenial anomaly, and discussion with a physician concerning pregnancy-related issues. We evaluated the following outcome variables: (1) the decision to discontinue anti-epileptic drug (AED) during a future pregnancy regardless of the medical indication; and (2) the decision to have fewer children because of epilepsy.ResultsWe enrolled a total of 186 women with epilepsy. (1) Fifty-eight percent of the women were considering discontinuing AED during a future pregnancy regardless of the medical indication, and 25% of the women decided to have fewer children because of epilepsy. (2) The decision to discontinue AED during a future pregnancy was associated with low-level pregnancy-related knowledge. (3) The decision to have fewer children because of epilepsy was associated with an exaggerated perception of the offspring's risk for developing epilepsy. (4) The women who had ever discussed pregnancy-related issues with their physician were less likely to decide to discontinue AED during a future pregnancy; however, a discussion on this issue had no impact on their decision to have fewer children because of epilepsy.ConclusionMore than 50% of the women would decide to discontinue AED during a future pregnancy, and 25% of the women stated that they would have fewer children because of epilepsy. These data highlight the importance of education on pregnancy-related issues and genetic risk counseling

    Achieving tolerant CO₂ electro-reduction catalyst in real water matrix

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    In order to achieve practical application of electrochemical CO₂ conversion technologies, the development of durable catalyst in real water matrix is essential because the use of catalysts only showing high performance within a well-refined environment cannot guarantee their feasibility in realistic conditions. Here, we report a design strategy for a catalyst, which shows excellent tolerance to deactivation factors, using a carbon-based material under more practical condition implemented by real tap water. Screening analyses on various components in tap water elucidated that the impurity group, which can be deposited on the catalyst surface and impede the active sites, such as copper, zinc, and especially iron are the main factors responsible for deactivation. Based on these findings, the structural modified nitrogen-doped carbon nanotube (denoted as ball mill N-CNT) was adopted as a catalyst design to secure durability. Consequently, the ball mill N-CNT revealed tolerance to the disclosed deactivation factors and showed stable performance during unprecedented long-time of 120 h in tap water media

    A Fatal Case of Intravascular Coagulation After Bee Sting Acupuncture

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    Bee stings can cause severe adverse reactions, leading to anaphylaxis, cardiovascular collapse, and death. In some cases, bee venom also induces disseminated intravascular coagulation (DIC). However, to our knowledge, there has been no fatal case of intravascular coagulation accompanied by anaphylaxis caused by bee sting acupuncture. Here, we report a fatal case of a 65-year-old woman with DIC, following anaphylactic shock after bee sting acupuncture. This case emphasizes that practitioners should consider anaphylaxis followed by coagulation abnormalities when a patient's vital signs are unstable after bee sting acupuncture

    Regression of esophageal varices during entecavir treatment in patients with hepatitis-B-virus-related liver cirrhosis

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    Recent studies suggest that liver cirrhosis is reversible after administering oral nucleos(t)ide analogue therapy to patients with hepatitis B virus (HBV) infection. However, few studies have addressed whether esophageal varices can regress after such therapy. We report a case of complete regression of esophageal varices during entecavir therapy in patients with HBV-related liver cirrhosis, suggesting that complications of liver cirrhosis such as esophageal varices can regress after the long-term suppression of HBV replication
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