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233 results on '"Qian, Chunqi"'

52. SIMULATION ANALYSIS OF BLOOD FLOW IN ARTERIES OF THE HUMAN ARM

Author

Pan Lingjiao, Qian Chunqi, Wu Quanyu, Tao Weige, and Liu Xiaojie

Subjects
business.industry, 0206 medical engineering, Biomedical Engineering, Biophysics, Carreau fluid, Bioengineering, 02 engineering and technology, Static pressure, Blood flow, Anatomy, Wrist, 020601 biomedical engineering, 01 natural sciences, Article, 010305 fluids & plasmas, body regions, medicine.anatomical_structure, medicine.artery, 0103 physical sciences, medicine, Upper limb, Radial artery, business, Ulnar artery, Artery
Abstract

Arteries in the upper limb play important roles in the circulation system of the human body. In particular, the radial artery has received considerable attention in traditional Chinese medicine for thousands of years. Here, a 3D model for the arm arteries has been created uncomplicated, in a Chinese adult’s left hand, from the magnetic resonance imaging data, using professional modeling software to restore the basic structure of the arm artery in human body, before being imported to Ansys software for simulation. Blood model has been only simulated, and using the blood density of constant parameter and viscosity using the Carreau fluid model, and using viscous-laminar model of Fluent to obtain the velocity profile, static pressure and shear stress in the brachial, interosseous, ulnar, radial and palmar arch arteries. In particular, the brachial and bifurcations have the high pressure and velocity profiles. The simulation results obtained here are also validated by those published in the literature and proved the ulnar artery prevails over the radial artery as a blood supplier to the vessels in the wrist and hand.

Published
2018

66. Metabolomics study of polysaccharide extracts from Polygonatum sibiricum in mice based on 1H NMR technology.

Author

Li, Tingting, Xu, Sheng, Bi, Jianli, Huang, Shengtang, Fan, Baolei, and Qian, Chunqi

Subjects
METABOLOMICS, CHEMICAL industry, ADENOSINE monophosphate, TECHNOLOGY, ASPARTIC acid, HISTIDINE, GLUCOSE analysis, POLYSACCHARIDES
Abstract

BACKGROUND Polygonatum sibiricum Liliaceae perennial herb, as a commonly used medicine and food homologous plant, has been widely used in clinical practice of Chinese medicine since ancient times, with a history of 2000 years. As the main active ingredient, P. sibiricum polysaccharides have important pharmacological effects in blood sugar reduction and antitumor, antioxidant and liver protection. RESULTS: Mouse models of P. sibiricum polysaccharides were used in combination with 1H NMR to investigate the metabolic regulation mechanism in mouse tissue and blood. The metabolite maps of the control group and the drug group in the liver had significant changes. The main differential metabolites were glucose 6‐phosphate, inositol, lactose, glutamylglycine, galactose, rhamnose, cis‐aconitic acid and histidine, indicating that there was definite correlation between the metabolic detection based on 1H NMR and the metabolic characteristics of P. sibiricum. The common differential metabolites obtained by overall metabolism analysis were 3‐hydroxybutyric acid, d‐ribose, adenosine phosphate, inositol, fructose 6‐phosphate, histidine, aspartic acid and cis‐aconitic acid. CONCLUSIONS: This work forms the basis for identification of metabolic states combined with metabolic pathways, which could be used as diagnostic and prognostic indicators, providing therapeutic targets for new diseases. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Published
2020
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75. Sensitive Enhancement of Vessel Wall Imaging With an Endoesophageal Wireless Amplified NMR Detector (WAND)

Author

Zeng, Xianchun, Barbic, Mladen, Chen, Liangliang, and Qian, Chunqi

Subjects
Carotid Arteries, Esophagus, Phantoms, Imaging, Image Processing, Computer-Assisted, Animals, Aorta, Thoracic, Equipment Design, Magnetic Resonance Imaging, Wireless Technology, Article, Rats
Abstract

To improve the imaging quality of vessel walls with an endoesophageal Wireless Amplified NMR Detector (WAND).A cylindrically shaped double-frequency resonator has been constructed with a single metal wire that is self-connected by a pair of nonlinear capacitors. The double-frequency resonator can convert wirelessly provided pumping power into amplified MR signals. This compact design makes the detector easily insertable into a rodent esophagus.The detector has good longitudinal and axial symmetry. Compared to an external surface coil, the WAND can enhance detection sensitivity by at least 5 times, even when the distance separation between the region of interest and the detector's cylindrical surface is twice the detector's own radius. Such detection capability enables us to observe vessel walls near the aortic arch and carotid bifurcation with elevated sensitivity.A cylindrical MRI detector integrated with a wireless-powered amplifier has been developed as an endoesophageal detector to enhance detection sensitivity of vessel walls. This detector can greatly improve the imaging quality for vessel regions that are susceptible to atherosclerotic lesions. Magn Reson Med 78:2048-2054, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Published
2016

79. MiRNA Extraction from Cell-Free Biofluid Using Protein Corona Formed around Carboxyl Magnetic Nanoparticles

Author

Xu, Shengqiang, Hossaini Nasr, Seyedmehdi, Chen, Daoyang, Zhang, Xiaoxian, Sun, Liangliang, Huang, Xuefei, and Qian, Chunqi

Abstract

MicroRNA (miRNA) in urine has been considered as a potential biomarker for early stage diagnosis of multiple diseases like urinary system cancer, kidney injury, and diabetes because of their many demonstrated advantages including long-term stability and noninvasiveness. However, the traditional enrichment and extraction processes of miRNAs from urine are cumbersome and tedious due to the low concentration and multiple carriers of miRNAs. Herein, we present a novel method to collect low concentrations of miRNAs from dilute solutions such as urine and cell culture medium. Ten nanometer core sized magnetic nanoparticles with carboxylic acid coating can adsorb low-concentration proteins, and form protein corona which makes them easy to aggregate and precipitate for subsequent isolation. In urine and cell culture medium, these nanoparticles can aggregate with proteins, including miRNAs-associated protein Argonaute 2 and microvesicle-related proteins, to form precipitates, so that miRNAs can be easily extracted from pellets by small amount of lysis buffer for subsequent analysis such as real-time PCR. Our method provides a facile way to enrich miRNAs from biofluids without the need of ultracentrifugation and immunoprecipitations, bringing remarkable convenience to miRNA-based biomarker research.

Published
2024
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81. Nonconvex compressive video sensing

Author

Chen, Liangliang, primary, Yan, Ming, additional, Qian, Chunqi, additional, Xi, Ning, additional, Zhou, Zhanxin, additional, Yang, Yongliang, additional, Song, Bo, additional, and Dong, Lixin, additional

Published
2016
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84. Live nephron imaging by MRI

Author

Qian, Chunqi, primary, Yu, Xin, additional, Pothayee, Nikorn, additional, Dodd, Stephen, additional, Bouraoud, Nadia, additional, Star, Robert, additional, Bennett, Kevin, additional, and Koretsky, Alan, additional

Published
2014
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91. Wireless Amplified Nuclear MR Detector (WAND) for High-Spatial-Resolution MR Imaging of Internal Organs: Preclinical Demonstration in a Rodent Model

Author

Qian, Chunqi, primary, Yu, Xin, additional, Chen, Der-Yow, additional, Dodd, Stephen, additional, Bouraoud, Nadia, additional, Pothayee, Nikorn, additional, Chen, Yun, additional, Beeman, Scott, additional, Bennett, Kevin, additional, Murphy-Boesch, Joseph, additional, and Koretsky, Alan, additional

Published
2013
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96. Deciphering laminar-specific neural inputs with line-scanning fMRI.

Author

Yu, Xin, Qian, Chunqi, Chen, Der-yow, Dodd, Stephen J, and Koretsky, Alan P

Subjects
*FUNCTIONAL magnetic resonance imaging, *SOMATOSENSORY cortex, *MOTOR cortex, *PHENOTYPIC plasticity, *NEURAL physiology, *LABORATORY rats
Abstract

Using a line-scanning method during functional magnetic resonance imaging (fMRI), we obtained high temporal (50-ms) and spatial (50-μm) resolution information along the cortical thickness and showed that the laminar position of fMRI onset coincides with distinct neural inputs in rat somatosensory and motor cortices. This laminar-specific fMRI onset allowed us to identify the neural inputs underlying ipsilateral fMRI activation in the barrel cortex due to peripheral denervation-induced plasticity. [ABSTRACT FROM AUTHOR]

Published
2014
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97. 14N Polarization Inversion Spin Exchange at Magic Angle (PISEMA)

Author

Qian, Chunqi, Fu, Riqiang, Gor’kov, Peter, Brey, William W., Cross, Timothy A., and Gan, Zhehong

Subjects
*POLARIZATION (Nuclear physics), *SPIN exchange, *PEPTIDES, *MEMBRANE proteins, *NITROGEN, *VALINE
Abstract

Abstract: Polarization Inversion Spin Exchange at Magic Angle (PISEMA) is a powerful experiment for determining peptide orientation in uniformly aligned samples such as planar membranes. In this paper, we present 14N-PISEMA experiment which correlates 14N quadrupolar coupling and 14N–1H dipolar coupling. 14N-PISEMA enables the use of 14N quadrupolar coupling tensor as an ultra sensitive probe for peptide orientation and can be carried out without the need of isotope enrichment. The experiment is based on selective spin-exchange between a proton and a single-quantum transition of 14N spins. The spin-exchange dynamics is described and the experiment is demonstrated with a natural abundant N-acetyl valine crystal sample. [Copyright &y& Elsevier]

Published
2009
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98. Novel 19F Activatable Probe for the Detection of Matrix Metalloprotease-2 Activity by MRI/MRS

Author

Yue, Xuyi, Wang, Zhe, Zhu, Lei, Wang, Yu, Qian, Chunqi, Ma, Ying, Kiesewetter, Dale O., Niu, Gang, and Chen, Xiaoyuan

Abstract

Matrix metalloproteases (MMPs) have been found to be highly expressed in a variety of malignant tumor tissues. Noninvasive visualization of MMP activity may play an important role in the diagnosis of MMP associated diseases. Here we report the design and synthesis of a set of fluorine-19 dendron-based magnetic resonance imaging (MRI) probes for real-time imaging of MMP-2 activity. The probes have the following features: (a) symmetrical fluorine atoms; (b) the number of fluorine atoms can be increased through facile chemical modification; (c) readily accessible peptide sequence as the MMP-2 substrate; (d) activatable 19F signal (off/on mode) via paramagnetic metal ion incorporation. Following optimization for water solubility, one of the probes was selected to evaluate MMP-2 activity by 19F magnetic resonance spectroscopy (MRS). Our results showed that the fluorine signal increased by 8.5-fold in the presence of MMP-2. The specific cleavage site was verified by mass spectrometry. The selected probe was further applied to detect secreted MMP-2 activity of living SCC7 squamous cell carcinoma cells. The fluorine signal was increased by 4.8-fold by MRS analysis after 24 h incubation with SCC7 cells. This type of fluorine probe can be applied to evaluate other enzyme activities by simply tuning the substrate structures. This symmetrical fluorine dendron-based probe design extends the scope of the existing 19F MRI agents and provides a simple but robust method for real-time 19F MRI application.

Published
2014
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