361 research outputs found

    Nanoscale domain engineering in SrRuO3_3 thin films

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    We investigate nanoscale domain engineering via epitaxial coupling in a set of SrRuO3_3/PbTiO3_3/SrRuO3_3 heterostructures epitaxially grown on (110)o_o-oriented DyScO3_3 substrates. The SrRuO3_3 layer thickness is kept at 55 unit cells, whereas the PbTiO3_3 layer is grown to thicknesses of 23, 45 and 90 unit cells. Through a combination of atomic force microscopy, x-ray diffraction and high resolution scanning transmission electron microscopy studies, we find that above a certain critical thickness of the ferroelectric layer, the large structural distortions associated with the ferroelastic domains propagate through the top SrRuO3_3 layer, locally modifying the orientation of the orthorhombic SrRuO3_3 and creating a modulated structure that extends beyond the ferroelectric layer boundaries.Comment: 19 pages, 6 figures, supplementary materials. arXiv admin note: text overlap with arXiv:2304.0694

    Distinct functional defect of three novel Brugada syndrome related cardiac sodium channel mutations

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    The Brugada syndrome is characterized by ST segment elevation in the right precodial leads V1-V3 on surface ECG accompanied by episodes of ventricular fibrillation causing syncope or even sudden death. The molecular and cellular mechanisms that lead to Brugada syndrome are not yet completely understood. However, SCN5A is the most well known responsible gene that causes Brugada syndrome. Until now, more than a hundred mutations in SCN5A responsible for Brugada syndrome have been described. Functional studies of some of the mutations have been performed and show that a reduction of human cardiac sodium current accounts for the pathogenesis of Brugada syndrome. Here we reported three novel SCN5A mutations identified in patients with Brugada syndrome in Taiwan (p.I848fs, p.R965C, and p.1876insM). Their electrophysiological properties were altered by patch clamp analysis. The p.I848fs mutant generated no sodium current. The p.R965C and p.1876insM mutants produced channels with steady state inactivation shifted to a more negative potential (9.4 mV and 8.5 mV respectively), and slower recovery from inactivation. Besides, the steady state activation of p.1876insM was altered and was shifted to a more positive potential (7.69 mV). In conclusion, the SCN5A channel defect related to Brugada syndrome might be diverse but all resulted in a decrease of sodium current

    Peripheral Sympathectomy for Raynaud's Phenomenon: A Salvage Procedure

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    We retrospectively reviewed the effectiveness of peripheral sympathectomy for severe Raynaud's phenomenon. In this study, a total of 14 digits from six patients with chronic digital ischemic change were included. All patients had pain, ulcer, or gangrenous change in the affected digits and were unresponsive to pharmacologic or other nonsurgical therapies. In all cases, angiography showed multifocal arterial lesions, so microvascular reconstruction was unfeasible. Peripheral sympathectomy was performed as a salvage procedure to prevent digit amputation. The results were analyzed according to reduction of pain, healing of ulcers, and prevention of amputation. In 12 of the 14 digits, the ulcers healed and amputation was avoided. In the other two digits, the ulcers improved and progressive gangrene was limited. As a salvage procedure for Raynaud's phenomenon recalcitrant to conservative treatment, peripheral sympathectomy improves perfusion to ischemic digits and enables amputation to be avoided

    Second-trimester Maternal Serum Quadruple Test for Down Syndrome Screening: A Taiwanese Population-based Study

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    SummaryObjectiveTo assess the usefulness of quadruple test screening for Down syndrome in Taiwan.Materials and MethodsMaternal serum concentrations of a-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A were measured in 21,481 pregnant women from 15 to 20 weeks of gestation.ResultsOf the 21,481 women, 977 returned values greater than the high-risk cut-off value (1 in 270). Most of these women (86.2%) decided to have an invasive procedure for genetic diagnosis. Nine cases of Down syndrome and 19 cases of other chromosomal anomalies were detected prenatally. Two children with Down syndrome were diagnosed after delivery even though a low estimated risk was determined following the quadruple test. The detection rate was 81.8% (nine out of 11 cases), with a 4.4% false-positive rate. The median multiple of the median value for a-fetoprotein, human chorionic gonadotropin, unconjugated estriol and inhibin A were 0.87, 2.34, 0.77 and 2.16, respectively, in affected cases.ConclusionThis is the first study of the quadruple test for Down syndrome in a Chinese population. Our findings suggested that the second-trimester quadruple test provides an effective screening tool for Down syndrome in Taiwan

    Depression is the Strongest Independent Risk Factor for Poor Social Engagement Among Chinese Elderly Veteran Assisted-living Residents

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    BackgroundSocial engagement prolongs the lifespan and preserves cognition in the elderly. However, most studies concerning social engagement have been conducted in Western countries; few have been performed in the Chinese population. This study attempted to identify the risk factors for poor social engagement among elderly veterans in Taiwan.MethodsA total of 597 male veterans were enrolled, with a mean age of 80.8 ± 5.0 years. This cross-sectional study employed the Resident Assessment Instrument (RAI) Minimum Data Set (MDS), the Geriatric Depression Scale–Short Form (GDS-SF), and the Mini-Mental State Examination (MMSE). Multivariate logistic regression analysis was done to investigate significant independent risk factors for poor social engagement, which were identified using the MDS Index of Social Engagement (ISE).ResultsMean ISE score was 1.5 ± 1.3 (range, 0–5); 52% of subjects had poor levels of social engagement (ISE < 2; 312/597). Regression analyses suggested that depression (OR, 6.6; 95% CI, 2.7–16.1; p < 0.001), illiteracy (OR, 2.2; 95% CI, 1.3–3.8; p = 0.003), the presence of unsettled relationships (OR, 3.6; 95% CI, 1.5–8.7; p = 0.004), and cognitive impairment (OR, 2.0; 95% CI, 1.1–3.9; p = 0.03) were significant independent risk factors for poor social engagement, after controlling for age, marital status, level of daily living activity and degree of sensory impairment.ConclusionPoor social engagement is common among Chinese assisted-living veteran home residents. Depression is the greatest risk factor of poor social engagement in this population

    P‐143: A Novel Current‐Scaling a‐Si:H TFTs Pixel Electrode Circuit for Active‐Matrix Organic Light‐Emitting Displays

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    Hydrogenated amorphous silicon thin‐film transistor (a‐Si:H TFT) pixel electrode circuit with a function of current scaling is proposed for active‐matrix organic light‐emitting displays (AM‐OLEDs). In contrast to the conventional current mirror pixel electrode circuit, in this circuit a high data‐to‐organic light‐emitting device (OLED) current ratio can be achieved, without increasing the a‐Si:H TFT size, by using a cascade structure of storage capacitors. Moreover, the proposed circuit can compensate for the variations of TFT threshold voltage. Simulation results, based on a‐Si:H TFT and OLED experimental data, showed that a data‐to‐OLED current ratio larger than 10 and a fast pixel programming time can be accomplished with the proposed circuit.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92010/1/1.2036579.pd

    Molecular and clinical analyses of 84 patients with tuberous sclerosis complex

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    BACKGROUND: Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by the development of multiple hamartomas in many internal organs. Mutations in either one of 2 genes, TSC1 and TSC2, have been attributed to the development of TSC. More than two-thirds of TSC patients are sporadic cases, and a wide variety of mutations in the coding region of the TSC1 and TSC2 genes have been reported. METHODS: Mutational analysis of TSC1 and TSC2 genes was performed in 84 Taiwanese TSC families using denaturing high-performance liquid chromatography (DHPLC) and direct sequencing. RESULTS: Mutations were identified in a total of 64 (76 %) cases, including 9 TSC1 mutations (7 sporadic and 2 familial cases) and 55 TSC2 mutations (47 sporadic and 8 familial cases). Thirty-one of the 64 mutations found have not been described previously. The phenotype association is consistent with findings from other large studies, showing that disease resulting from mutations to TSC1 is less severe than disease due to TSC2 mutation. CONCLUSION: This study provides a representative picture of the distribution of mutations of the TSC1 and TSC2 genes in clinically ascertained TSC cases in the Taiwanese population. Although nearly half of the mutations identified were novel, the kinds and distribution of mutation were not different in this population compared to that seen in larger European and American studies

    Discovery of New Eunicellins from an Indonesian Octocoral Cladiella sp.

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    Two new 11-hydroxyeunicellin diterpenoids, cladieunicellin F (1) and (–)-solenopodin C (2), were isolated from an Indonesian octocoral Cladiella sp. The structures of eunicellins 1 and 2 were established by spectroscopic methods, and eunicellin 2 was found to be an enantiomer of the known eunicellin solenopodin C (3). Eunicellin 2 displayed inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils. The previously reported structures of two eunicellin-based compounds, cladielloides A and B, are corrected in this study
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