4 results
Relationship between syncopal symptoms and head-up tilt test modes
- Shuo Wang, Yali Peng, Yuwen Wang, Fang Li, Yi Xu, Huifen Zheng, Heli Yuan, Chunyan Hu, Donglei Liao, Hong Cai, Juan Zhang, Wen Li, Yiyi Ding, Wenhua Zhang, Xiaohong Xue, Xiaoyan Liu, Liping Zhu, Deyu Liu, Meihua Kang, Liping Liu, Weihong Chu, Xiaoming Li, Xuemei Luo, Runmei Zou, Cheng Wang
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- Journal:
- Cardiology in the Young , First View
- Published online by Cambridge University Press:
- 05 April 2024, pp. 1-6
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Objective:
Head-up tilt test (HUTT) is an important tool in the diagnosis of pediatric vasovagal syncope. This research will explore the relationship between syncopal symptoms and HUTT modes in pediatric vasovagal syncope.
Methods:A retrospective analysis was performed on the clinical data of 2513 children aged 3–18 years, who were diagnosed with vasovagal syncope, from Jan. 2001 to Dec. 2021 due to unexplained syncope or pre-syncope. The average age was 11.76 ± 2.83 years, including 1124 males and 1389 females. The patients were divided into the basic head-up tilt test (BHUT) group (596 patients) and the sublingual nitroglycerine head-up tilt test (SNHUT) group (1917 patients) according to the mode of positive HUTT at the time of confirmed pediatric vasovagal syncope.
Results:(1) Baseline characteristics: Age, height, weight, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and composition ratio of syncope at baseline status were higher in the BHUT group than in the SNHUT group (all P < 0.05). (2) Univariate analysis: Age, height, weight, HR, SBP, DBP, and syncope were potential risk factors for BHUT positive (all P < 0.05). (3) Multivariate analysis: syncope was an independent risk factor for BHUT positive, with a probability increase of 121% compared to pre-syncope (P<0.001).
Conclusion:The probability of BHUT positivity was significantly higher than SNHUT in pediatric vasovagal syncope with previous syncopal episodes.
Testing the role of phonetic knowledge in Mandarin tone sandhi*
- Jie Zhang, Yuwen Lai
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Phonological patterns often have phonetic bases. But whether phonetic substance should be encoded in synchronic phonological grammar is controversial. We aim to test the synchronic relevance of phonetics by investigating native Mandarin speakers' applications of two exceptionless tone sandhi processes to novel words: the contour reduction 213→21/—T (T≠213), which has a clear phonetic motivation, and the perceptually neutralising 213→35/—213, whose phonetic motivation is less clear. In two experiments, Mandarin subjects were asked to produce two individual monosyllables together as two different types of novel disyllabic words. Results show that speakers apply the 213→21 sandhi with greater accuracy than the 213→35 sandhi in novel words, indicating a synchronic bias against the phonetically less motivated pattern. We also show that lexical frequency is relevant to the application of the sandhis to novel words, but cannot account alone for the low sandhi accuracy of 213→35.
The Control of Dna Structure and Topology: An Overview
- Nadrian C. Seeman, Yuwen Zhang, Shou Ming Du, Hui Wang, John E. Mueller, Yinli Wang, Bing Liu, Jing Qi, Junghuei Chen
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- Journal:
- MRS Online Proceedings Library Archive / Volume 351 / 1994
- Published online by Cambridge University Press:
- 15 February 2011, 57
- Print publication:
- 1994
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The control of structure on the nanoscale relies on intermolecular interactions whose specificity and geometry can be treated on a predictive basis. DNA fulfills this criterion, and provides an extremely convenient construction medium: The sticky-ended association of DNA molecules occurs with high specificity, and it results in the formation of double helical DNA, whose structure is well known. The use of stable branched DNA molecules permits one to make stick-figures. We have used this strategy to construct in solution a covalently closed DNA molecule whose helix axes have the connectivity of a cube: The molecule has twelve double helical edges; every edge is two helical turns in length, resulting in a hexacatenane, each of whose strands corresponds to a face of the object. We have developed a solid-support-based synthetic methodology that is more effective than solution synthesis. The key features of the technique are control over the formation of each edge of the object, and the topological closure of each intermediate. The isolation of individual objects on the surface of the support eliminates cross-reactions between growing products. The solid-support-based methodology has been used to construct a molecule whose helix axes have the connectivity of a truncated octahedron. This figure has 14 faces, of which six are square and eight are hexagonal; this Archimedean polyhedron contains 24 vertices and 36 edges, and is built from a 14-catenane of DNA. Knotted molecules appear to be the route for cloning DNA objects. It is possible to construct three knotted topologies, as well as a simple cyclic molecule from a single precursor, by control of solution conditions. Control of both branching and braiding topology is strong in this system, but control of 3-D structure remains elusive. Our key aim is the formation of prespecified 2-D and 3-D periodic structures for use in diffraction experiments. Another application envisioned is scaffolding for the assembly of molecular electronic devices.
Chemical Synthesis of Nanostructures
- Nadrian C. Seeman, Yuwen Zhang, Tsu-Ju Fu, Siwei Zhang, Yinli Wang, Junghuei Chen
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- Journal:
- MRS Online Proceedings Library Archive / Volume 330 / 1993
- Published online by Cambridge University Press:
- 15 February 2011, 45
- Print publication:
- 1993
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The control of structure on the nanoscale relies on intermolecular interactions whose specificity and geometry can be treated on a predictive basis. With this criterion in mind, DNA is an extremely favorable construction medium: The sticky-ended association of DNA molecules occurs with high specificity, and it results in the formation of double helical DNA, whose structure is well known. The use of stable branched DNA molecules permits one to make stick-figures. We have used this strategy to construct a covalently closed DNA molecule whose helix axes have the connectivity of a cube. The molecule has twelve double helical edges; each edge is two helical turns in length, resulting in a hexacatenane, each of whose strands corresponds to a face of the object. The cube has been fabricated in solution, which is inefficient. We have developed a solid-support-based synthetic methodology that is much more effective. The key features of the technique are control over the formation of each edge of the object, and the topological closure of each intermediate. Each edge results from the restriction of two hairpins, which are then ligated together. The isolation of individual objects on the surface of the support permits one to use both symmetric and asymmetric sites in the formation of edges that close polygons. We have used solid-support-based methodology to construct a molecule whose helix axes have the connectivity of a truncated octahedron. This figure has 14 faces, of which six are ideally square and eight are hexagonal; this Archimedean polyhedron contains 24 vertices and 36 edges. Control of topology is strong in this system, but control of 3-D structure remains elusive. Topological control is enhanced by the use of topological protection techniques. Our key aim is the formation of prespecified 2-D and 3-D periodic structures with defined topologies. Applications envisioned include nanomanipulators and scaffolding for molecular electronic devices.