756 research outputs found
N Am J Med Sci (Boston)
No full textLipoprotein-associated phospholipase A2 (Lp-PLA|) is a novel inflammatory biomarker. Basic research has shown that Lp-PLA| is involved in the pathogenesis of atherosclerosis. In the past decade, an increasing number of epidemiological studies have investigated the association of Lp-PLA| with atherosclerosis, but its roles in the different stages of atherosclerosis are not established. By undertaking a systematic review of the epidemiological studies on the relationship between Lp-PLA| and atherosclerotic cardiovascular disease (CVD)/subclinical atherosclerosis, we tried to evaluate the relationship between Lp-PLA| and the different stages of atherosclerosis. MEDLINE, Cochrane Library, and National Knowledge Infrastructure (CNKI) were searched up to September 1st, 2011. The references in all the located articles were manually searched. Epidemiological studies on the association of Lp-PLA| with CVD and subclinical atherosclerosis, with total CVD, coronary heart disease (CHD), stroke, and subclinical atherosclerosis as their observation endpoints or outcome variables, were included in this study. Studies which did not assess the hazard ratio (HR), relative risk (RR), or odds ratio (OR) of Lp-PLA| or which did not adjust for other known risk factors were excluded. The general information, study design, sample size, outcome variables and their definitions, follow-up duration, Lp-PLA| measurements, variables adjusted in the multivariate analysis and main results in the literatures were retrieved. Thirty-nine studies were enrolled in this systematic review. Thirty-three studies (49, 260 subjects) investigated the relationship between Lp-PLA| and CVD, among which 31 showed that increased Lp-PLA| is associated to high risk for incidence or mortality of CVD: HR/RR per 1 standard deviation (SD) increase = 1.17-1.40; RR for the highest as compared with the lowest quartile was 1.41-3.75 (1.8-2.5 in most studies). Six studies (four cross-sectional studies and two case-control studies, with an overall sample size of 5,537) explored the relationship between Lp-PLA| and subclinical atherosclerosis; among them, two studies demonstrated that Lp-PLA| was associated with coronary artery calcification in young adults and men. In conclusion, many epidemiological studies have demonstrated that Lp-PLA| increases the risk of clinical CVD events. However, whether there is a similar association between Lp-PLA| and subclinical atherosclerosis remains unclear. Whether Lp-PLA| exerts its effect during the occurrence of clinical events promoted by unstable plaques or at the early stage of atherosclerosis needs to be clarified in further prospective studies.CC999999/Intramural CDC HHSUnited States
2D fin field-effect transistors integrated with epitaxial high-k gate oxide
No full textPrecise integration of two-dimensional (2D) semiconductors and high-dielectric-constant (k) gate oxides into three-dimensional (3D) vertical-architecture arrays holds promise for developing ultrascaled transistors1–5, but has proved challenging. Here we report the epitaxial synthesis of vertically aligned arrays of 2D fin-oxide heterostructures, a new class of 3D architecture in which high-mobility 2D semiconductor fin Bi2O2Se and single-crystal high-k gate oxide Bi2SeO5 are epitaxially integrated. These 2D fin-oxide epitaxial heterostructures have atomically flat interfaces and ultrathin fin thickness down to one unit cell (1.2 nm), achieving wafer-scale, site-specific and high-density growth of mono-oriented arrays. The as-fabricated 2D fin field-effect transistors (FinFETs) based on Bi2O2Se/Bi2SeO5 epitaxial heterostructures exhibit high electron mobility (μ) up to 270 cm2 V−1 s−1, ultralow off-state current (IOFF) down to about 1 pA μm−1, high on/off current ratios (ION/IOFF) up to 108 and high on-state current (ION) up to 830 μA μm−1 at 400-nm channel length, which meet the low-power specifications projected by the International Roadmap for Devices and Systems (IRDS)6. The 2D fin-oxide epitaxial heterostructures open up new avenues for the further extension of Moore’s law. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.11Nsciescopu
Remarkable synergistic effect between copper(I) and ionic liquids for promoting chemical fixation of CO2
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Recently, efficient chemical conversion of CO2 into high value chemicals at room temperature and atmospheric pressure without using noble metal catalysts remains a great challenge. In this work, we find that the carboxylative cyclization of propargylic alcohols with CO2 can proceed at 60 degrees C and ambient pressure by using a combination of CuI and an ionic liquid (IL) 1,8-diazabicyclo-[5.4.0]-7-undecenium trifluoroethanol ([DBUH] [TFE]) as catalyst. By simple extraction after the reactions, a series of desired products have been obtained in good to excellent yields with this highly efficient catalyst system. Spectroscopic investigations and DFT calculations demonstrate that such a high efficiency originates from remarkable synergistic catalysis between Cu(I) and the IL on substrates. In addition, it is worth noting that this catalyst system also works well for the carboxylative cyclization of propargylic amines even at ambient temperature and pressure, with the highest turnover number among the reported base metals catalytic systems.</p
TCM body constitution study of patients with hypertension
No full textHypertension is a global health concern. Traditional Chinese Medicine (TCM) is becoming popular and often used among hypertensive patients. Traditional Chinese Medicine Body Constitution (TCMBC) is part of the TCM concept. Currently, in Singapore, there is no study focusing on the types of TCMBC that Singapore residents with hypertension have. The objective of this study is to investigate the TCMBC of Singapore residents with hypertension, henceforth providing epidemiological evidence for the theory of correlation between TCM body constitution and disease.A questionnaire was designed to target a total of 35 hypertensive Singapore residents. Phlegm-dampness, qi-deficiency, yang-deficiency, and yin-deficiency constitutions were the dominant constitution types of hypertension in Singapore. Phlegm-dampness constitution was significantly higher in the age above 60 than in the 20-39 (P=0.003). Yang-deficiency constitution in the 20-39 was significantly higher than in the 40-59 (P=0.027). Qi-deficiency constitution was significantly higher in males than in females (P=0.040) while yin-deficiency in females was significantly higher than in males (P=0.036). Phlegm-dampness, qi-deficiency, yang-deficiency, and yin-deficiency constitutions were the major influential factors of hypertension in Singapore. Personalized treatment and prevention of hypertension could be given based on a person’s constitution.Bachelor of Science in Biological Science
Simulation-to-real generalization for deep-learning-based refraction-corrected ultrasound tomography image reconstruction
No full textObjective. The image reconstruction of ultrasound computed tomography is computationally expensive with conventional iterative methods. The fully learned direct deep learning reconstruction is promising to speed up image reconstruction significantly. However, for direct reconstruction from measurement data, due to the lack of real labeled data, the neural network is usually trained on a simulation dataset and shows poor performance on real data because of the simulation-to-real gap.Approach. To improve the simulation-to-real generalization of neural networks, a series of strategies are developed including a Fourier-transform-integrated neural network, measurement-domain data augmentation methods, and a self-supervised-learning-based patch-wise preprocessing neural network. Our strategies are evaluated on both the simulation dataset and real measurement datasets from two different prototype machines.Main results. The experimental results show that our deep learning methods help to improve the neural networks' robustness against noise and the generalizability to real measurement data.Significance. Our methods prove that it is possible for neural networks to achieve superior performance to traditional iterative reconstruction algorithms in imaging quality and allow for real-time 2D-image reconstruction. This study helps pave the path for the application of deep learning methods to practical ultrasound tomography image reconstruction based on simulation datasets.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Medical ImagingImPhys/Van Dongen gou
A new approach for event study of private placement announcement effect: Evidence from China
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