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Search Results: 1 - 10 of 104269 matches for " Zhaoqi Zhang "
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MDCT Angiography Imaging Presentation of ALCAPA in Adults  [PDF]
Qinyi Dai, Biao Lv, Zhaoqi Zhang
Advances in Computed Tomography (ACT) , 2013, DOI: 10.4236/act.2013.21005
Abstract: Objective: To make a pictorial presentation of the anomalous origin of left coronary artery arising from the pulmonary artery (ALCAPA) appearances in adults on MDCT angiography. Methods: A retrospective evaluation was performed between 2005 and 2011 by ECG-gated coronary MDCT angiography. Total 8 patients included (9-51 years, mean age 29 years, 7 female). Image quality was evaluated firstly. Multi planar reformations (MPRs), maximum intensity projections (MIPs) and 3D volume-rendering techniques were used to evaluate image features. In addition, right and left coronary artery orifices were measured for each case. Results: Total 8/70,000 cases diagnosed ALCAPA by MDCT exam, all image qualities were acceptable. As the diagnose key point, all left coronary artery origin were clearly described, and indirect signs such as dilated and tortuous right/left arteries and collateral vessels between them, enlarged left ventricle were also well showed, the dilated degree of both the RCA and the LCA were marked with ages, the diameter of RCA for each case were a mild wider than that of left one. Other combined signs like papillary muscle calcification, bronchial arteries from aorta to the cardiac and coronary artery degeneration change were also included by MDCT angiography findings in a single data acquisition. No combined inter cardiac malformations in our group. Conclusion: ECG-gated MDCT an-giography plays an important role as a first-line modality in assessment of ALCAPA.
Non-disturbance criteria of quantum measurements
Wu Zhaoqi,Zhang Shifang,Wu Junde
Mathematics , 2009,
Abstract: Using the general sequential product proposed by Shen and Wu in [J. Phys. A: Math. Theor. 42, 345203, 2009], we derive three criteria for describing non-disturbance between quantum measurements that may be unsharp with such new sequential products, which generalizes Gudder's results.
Local community extraction in directed networks
Xuemei Ning,Zhaoqi Liu,Shihua Zhang
Computer Science , 2015,
Abstract: Network is a simple but powerful representation of real-world complex systems. Network community analysis has become an invaluable tool to explore and reveal the internal organization of nodes. However, only a few methods were directly designed for community-detection in directed networks. In this article, we introduce the concept of local community structure in directed networks and provide a generic criterion to describe a local community with two properties. We further propose a stochastic optimization algorithm to rapidly detect a local community, which allows for uncovering the directional modular characteristics in directed networks. Numerical results show that the proposed method can resolve detailed local communities with directional information and provide more structural characteristics of directed networks than previous methods.
Cardiovascular magnetic resonance of quinticuspid aortic valve with aortic regurgitation and dilated ascending aorta
Yanfeng Meng, Lijun Zhang, Zhaoqi Zhang, Yongmei Wang, Xiaoming Yang
Journal of Cardiovascular Magnetic Resonance , 2009, DOI: 10.1186/1532-429x-11-28
Abstract: Aortic valve malformation is a common congenital cardiac anomaly in the adult population. Dysfunction of the malformed aortic valve has been shown to cause significant morbidity and mortality. Among the malformations, bicuspid is the most common form, which has been identified in 1–2% of population with male predominance [1]. To our knowledge, an aortic valve containing 5 leaflets (quinticuspid) is very rare [2]. Here we report a case of quinticuspid aortic valve associated with aortic regurgitation and dilation of the ascending aorta.A 24-year-old Chinese man presented with worsening symptoms of palpitation, chest discomfort and shortness of breath over a two-year period. There was no prior history of rheumatic fever or endocarditis. On physical examination, his pulse was 68 per minute with a blood pressure of 145/41 mmHg. Subsequently, the patient underwent a series of imaging studies including echocardiography, chest X-ray, dual source x-ray computed tomography (CT) and cardiovascular magnetic resonance (CMR) (Figure 1), which showed a quinticuspid aortic valve. The CT scan demonstrated an aortic valve with 5 valve cusps and slightly thickened leaflet edges. In the systolic phase, the valve orifice measures 6.3 cm2 in area and opened like a pentagon, while in the diastolic phase, the valve orifice measured 1.2 cm2 in area and closed like pentagram (Figure 1a, b, d, e). Five sinuses of valsalva were identified with variable sizes, of which the posterior sinus was notably smaller than all other sinuses. CMR SSFP for the cine sequence demonstrated incomplete closure of the five aortic valve cusps, in which a small orifice was found in diastolic phase (Figure 1d, Additional file 1). In addition, aortic regurgitation was noted as blood back-flow was demonstrated from aorta to left ventricle at diastolic phase (Figure 1f). Phase contrast images demonstrated the peak flow velocity of regurgitation at 480 cm/s. Furthermore, the patient was found to have an enlarged left
Myocardial fibrosis in desmin-related hypertrophic cardiomyopathy
Yi He, Zhaoqi Zhang, Daojun Hong, Qinyi Dai, Tengyong Jiang
Journal of Cardiovascular Magnetic Resonance , 2010, DOI: 10.1186/1532-429x-12-68
Abstract: Desmin is a primary element of the intermediate filament network in skeletal, cardiac and smooth muscle cells. Desmin-related myopathy (DRM) is an autosomally inherited skeletal and cardiac muscular myopathy mainly caused by mutations in the desmin gene [1]. DRM is characterized by progressive skeletal muscle weakness, cardiomyopathy, and cardiac conduction disease. The cardiac phenotype of DRM includes cardiac arrhythmias and different types of cardiomyopathy. However, cardiac symptoms are the leading cause of death in most patients [2]. Desmin-related cardiomyopathy is usually evaluated by echocardiography through functional and morphological changes. In recent years however, cardiovascular magnetic resonance (CMR) in combination with late gadolinium enhancement (LGE) imaging has been used to differentiate normal myocardium from a variety of myocardial diseases associated with necrosis or fibrosis. We describe a case of desmin-related hypertrophic cardiomyopathy with myocardial fibrosis detected by CMR, which has not been previously reported.A 16 year old female presented to our cardiac department with progressive exertional dyspnea, palpitation, and skeletal muscle weakness for about two years. Two years ago she was diagnosed with hypertrophic cardiomyopathy by echocardiography. Her laboratory data showed creatine kinase (CK) 996 HU/L, brain natriuretic peptide(BNP) 2634 Hpg/ml. The electrocardiogram showed atrial fibrillation. At the referring hospital, skeletal muscle biopsies and mutation screening of the desmin gene had been performed according to the neurological workup of pathology.Tranthoracic echocardiography showed symmetrical myocardial hypertrophy of interventricular septum and the wall of left ventricle. The wall motion was normal. Left ventricular ejection fraction (LVEF) was 66%, left ventricular (LV) diastolic (DD) and systolic (SD) diameter was 40 and 26 mm, respectively. The left atrium (LA) was dilated with diameter of 56 mm.CMR was performed wi
Natural history of spontaneous aortic intramural hematoma progression: Six years follow-up with cardiovascular magnetic resonance
Xiaohai Ma, Zhaoqi Zhang, Zhanming Fan, Lei Zhao, Jing Yu
Journal of Cardiovascular Magnetic Resonance , 2010, DOI: 10.1186/1532-429x-12-27
Abstract: Spontaneous aortic intramural hematoma (IMH), which first described in 1920 by Krukenberg as "dissection without intimal tear", results from the spontaneous rupture of the vasa vasorum of the aortic wall. IMH most frequently involves the ascending aorta (type A) or proximal descending aorta (type B). This condition presents clinically as severe chest pain radiating to the back, which is similar to aortic dissection (AD). Systemic hypertension is the leading risk factor for spontaneous IMH. Recent advances in imaging techniques have significantly improved the diagnostic accuracy and enhanced clinical understanding of IMH. The natural history of spontaneous IMH is different from classical AD and its time course of IMH can vary significantly, so early diagnosis and close follow-up is desirable. We describe a spontaneous IMH case followed for 6 years by cardiovascular magnetic resonance (CMR). The patient progressed through different stages, including hematoma absorption, ulcer-like lesion emergence, aneurysm enlargement and limited AD.A 65-year-old female with a long history of hypertension was referred to emergency room because of acute chest pain that persisted over one day. The echocardiogram showed a widening of the lumen of the ascending aorta. A thoracic aorta CMR examination (Siemens Sonata 1.5T, Erlangen, Germany) was performed for further evaluation. The imaging protocol included three-dimension contrast-enhanced magnetic resonance angiography (3D CE MRA, TR/TE 2.2/0.8; FOV 320 × 380 mm; effective thickness 1.23 ± 1.60 mm) and true fast imaging steady-state precession (true FISP) MRI (TR/TE 3.2/1.6 ms; field of view (FOV), 300 × 400 mm; matrix, 300 × 512; thickness, 6 mm). The true FISP images were acquired without cardiac gating. A stack of two-dimensional images were acquired in approximately 15~18 seconds. Each acquisition had 10 slices. Gadopentetate dimeglumine (0.1 mmol/kg, Magnevist, Bayer-Schering, Germany) was administrated intravenously followed by 2
Diatom-based reconstruction of Holocene environmental changes in Angren Lake, Southern Tibet
Shengfeng Li,Fubao Wang,Jie Zhang,Xuhui Shen,Zhaoqi Zeng
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02886140
Abstract: Based on the diatom analysis the climatic sequence between 11 000 and 6 000 aBP in Angren, southern Tibet is established, i.e. cold period (11 095-9 970 aBP)→ temperate period (9 970-9 870 aBP) → Anathermal (9 870-9 770 aBP)→ cool-dry period (9 770-8 740 aBP) → super-megathermal (8 740-8 590 aBP)→ Megathermal (8 590-5 970 aBP). And the opinion that the reaction of diatom to temperature change is more sensitive than to other ecological factors has been pointed out and certified.
Morphology and Microstructure of As-Synthesized Anodic TiO2 Nanotube Arrays
Cao Chunbin,Zhang Guoshun,Song Xueping,Sun Zhaoqi
Nanoscale Research Letters , 2011,
Abstract: The as-grown structure of electrochemically synthesized titania nanotube arrays is investigated by scanning electron microscope (SEM) in combination with transmission electron microscope (TEM) as well as X-ray diffraction (XRD). The analysis reveals a preferred growth direction of the nanotubes relative to the substrate surface and the well control on the nanotube arrays morphology. The crystal structure of the anatase phase is detected and exists in the tube walls without any thermal treatment, which makes it possible to realize the application of as-formed TiO2 nanotubes avoiding the degradation of the nanotube structures when sintering. In addition, a new growth, layered model of the anodic TiO2 nanotubes is presented to obtain further understanding of the growth mechanism.
MRI of Auto-Transplantation of Bone Marrow-Derived Stem-Progenitor Cells for Potential Repair of Injured Arteries
Yanfeng Meng, Feng Zhang, Tiffany Blair, Huidong Gu, Hongqing Feng, Jinnan Wang, Chun Yuan, Zhaoqi Zhang, Bensheng Qiu, Xiaoming Yang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031137
Abstract: Background This study was to validate the feasibility of using clinical 3.0T MRI to monitor the migration of autotransplanted bone marrow (BM)-derived stem-progenitor cells (SPC) to the injured arteries of near-human sized swine for potential cell-based arterial repair. Methodology The study was divided into two phases. For in vitro evaluation, BM cells were extracted from the iliac crests of 13 domestic pigs and then labeled with a T2 contrast agent, Feridex, and/or a fluorescent tissue marker, PKH26. The viability, the proliferation efficiency and the efficacies of Feridex and/or PKH26 labeling were determined. For in vivo validation, the 13 pigs underwent endovascular balloon-mediated intimal damages of the iliofemoral arteries. The labeled or un-labeled BM cells were autotransplanted back to the same pig from which the BM cells were extracted. Approximately three weeks post-cell transplantation, 3.0T T2-weighted MRI was performed to detect Feridex-created signal voids of the transplanted BM cells in the injured iliofemoral arteries, which was confirmed by subsequent histologic correlation. Principal Findings Of the in vitro study, the viability of dual-labeled BM cells was 95–98%. The proliferation efficiencies of dual-labeled BM cells were not significantly different compared to those of non-labeled cells. The efficacies of Feridex- and PKH26 labeling were 90% and 100%, respectively. Of the in vivo study, 3.0T MRI detected the auto-transplanted BM cells migrated to the injured arteries, which was confirmed by histologic examinations. Conclusion This study demonstrates the capability of using clinical 3.0T MRI to monitor the auto-transplantation of BM cells that migrate to the injured arteries of large animals, which may provide a useful MRI technique to monitor cell-based arterial repair.
Involvement of the crebellum in sequential finger movement learning: Evidence from functional magnetic resonance imaging
Zhu Yihong,Di Haibo,Yuan Yi,Ren Jin’ge,Yu Wei,Zhang Zhaoqi,Gao Jiahong,Weng Xuchu,Chen Yizhang
Chinese Science Bulletin , 2005, DOI: 10.1360/982005-520
Abstract: Whether the cerebellum is involved in voluntary motor learning or motor performance is the subject of a new debate. Using functional magnetic resonance imaging (fMRI), we examined cerebellar activation in eight volunteers before and after an extended period of training. Activation volume on both sides of cerebellum after learning was significantly reduced compared to that before learning even under the same motor frequency. Remarkably, while motor frequency for the training sequence was significantly higher than the control sequence after 41 d of learning, activation in the cerebellum for both sequences, with respect to activation loci and volumes, was very similar. These results suggest that the cerebellum was involved in motor learning but not motor performance. Changes of cerebellar activation from training thus appear to be associated with learning but not with improvement on task performance.
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