591 research outputs found

    Effective-range-expansion study of near threshold heavy-flavor resonances

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    In this work we study the resonances near the thresholds of the open heavy-flavor hadrons using the effective-range-expansion method. The unitarity, analyticity and compositeness coefficient are also taken into account in our theoretical formalism. We consider the Zc(3900)Z_c(3900), X(4020)X(4020), χc1(4140)\chi_{c1}(4140), ψ(4260)\psi(4260) and ψ(4660)\psi(4660). The scattering lengths and effective ranges from the relevant elastic SS-wave scattering amplitudes are determined. Tentative discussions on the inner structures of the aforementioned resonances are given.Comment: 10 pages. Comparisons with other ways to define the compositeness are included. To match the published versio

    高血压合并主动脉夹层患者高血压特征及院前降压治疗

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    Objective: To summarize hypertension characteristics and pre hospital antihypertensive therapy in patients with hypertension and aortic dissection, to explore the measures of prevention and control. Methods:  683 patients with hypertension complicated with aortic dissection patients (AD group), 8974 patients with hypertension (hypertension group), during the five years from October 2009 to October 2014, were analyzed retrospectively according to the hospital medical records data combined with outpatient clinical data.Retrospective analysis of hypertension characteristics and pre hospital antihypertensive therapy from the two groups of patients when first diagnosed was conducted. Results: The two groups ratio of diabetes, coronary heart disease, hyperlipidemia, renal insufficiency, have no statistical difference. Most patients in AD group have over 10 years’ history of hypertension (P <0.05).The incidence of aortic dissection in men of AD group is higher than the hypertensive group(P <0.05). The ratio of 40~60 years in AD group is more than that in hypertensive group (P <0.05). The ratio of stage 3 hypertension in AD group is more than that in hypertension group (P < 0.05).The ratio of no antihypertensive treatment in patients in the AD group is more than that in hypertension group (P < 0.05).The average age of onset in AD group was lower than that in hypertension group (P<0.05). The ratio of patients in the AD group treated with ARB or ACEI antihypertensive was lower than that in hypertension group (P<0.05). Conclusion:  Hypertension complicated with aortic dissection is mostly accompanied by more than 10 years’ history of hypertension in most male patients of 40~60 age group, with grade 3 hypertension. Most did not receive antihypertensive treatment, the average age of onset is low, using ARB or ACEI for the treatment of patients is less.目的: 总结高血压合并主动脉夹层(aortic dissection,AD)患者入院时高血压特征及院前降压治疗,探讨防治措施。方法:根据住院病历资料结合门诊高血压微机管理病例资料分析2009年10月至2014年10月5年期间存活的683例高血压合并主动脉夹层患者(AD组),高血压病患者8974例(高血压组),对二组患者首诊时的高血压特征及院前降压治疗情况进行回顾性分析。结果:两组糖尿病、冠心病、高脂血症、肾功能不全比例无统计学差异。AD组多有10年以上的高血压病史(P<0.05)。AD组男性主动脉夹层发生率多于高血压组(P<0.05)。AD组40-60岁比例多于高血压组(P<0.05)。AD组高血压3级多于高血压组(P<0.05)。AD组未降压治疗者比例多于高血压组(P<0.05)。AD组发病平均年龄低于高血压病组(P<0.05)。AD组采用ARB或ACEI降压治疗者少于高血压组(P<0.05)。结论:高血压合并主动脉夹层多有10年以上高血压病史,男性患者多,在40-60岁年龄段多,3级高血压多,未接受降压治疗者多,发病平均年龄低,采用ARB或ACEI治疗者少

    Electric field tunable multi-state tunnel magnetoresistances in 2D van der Waals magnetic heterojunctions

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    Magnetic tunnel junction (MTJ) based on van der Waals (vdW) magnetic layers has been found to present excellent tunneling magnetoresistance (TMR) property, which has great potential applications in field sensing, non-volatile magnetic random access memories, and spin logics. Although MTJs composed of multilayer vdW magnetic homojunctions have been extensively investigated, the ones composed of vdW magnetic heterojunction is still to be explored. Here we use first-principles approaches to reveal that the magnetic heterojunction MTJs have much more distinguishable TMR values than the homojunction ones. In the MTJ composed of bilayer CrI3/bilayer Cr2Ge2Te6 heterojunction, we find there are eight stable magnetic states, leading to seven distinguishable electronic resistances. As a result, six sizable TMRs larger than 600% can be obtained (the maximum TMR is up to 120,000%). The number of distinguishable memories is more than two times larger than that of a four-layered homojunction MTJ. The underlying relationships among magnetic state, spin-polarized band structures, and transmission spectrums are further revealed to explain the multiple TMR values. We also find that the magnetic states and thus TMRs can be efficiently modulated by an external electric field. This study opens an avenue to the design of high-performance MTJ devices based on vdW heterojunctions.Comment: 6 figure

    Automatic Ship Detection of Remote Sensing Images from Google Earth in Complex Scenes Based on Multi-Scale Rotation Dense Feature Pyramid Networks

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    Ship detection has been playing a significant role in the field of remote sensing for a long time but it is still full of challenges. The main limitations of traditional ship detection methods usually lie in the complexity of application scenarios, the difficulty of intensive object detection and the redundancy of detection region. In order to solve such problems above, we propose a framework called Rotation Dense Feature Pyramid Networks (R-DFPN) which can effectively detect ship in different scenes including ocean and port. Specifically, we put forward the Dense Feature Pyramid Network (DFPN), which is aimed at solving the problem resulted from the narrow width of the ship. Compared with previous multi-scale detectors such as Feature Pyramid Network (FPN), DFPN builds the high-level semantic feature-maps for all scales by means of dense connections, through which enhances the feature propagation and encourages the feature reuse. Additionally, in the case of ship rotation and dense arrangement, we design a rotation anchor strategy to predict the minimum circumscribed rectangle of the object so as to reduce the redundant detection region and improve the recall. Furthermore, we also propose multi-scale ROI Align for the purpose of maintaining the completeness of semantic and spatial information. Experiments based on remote sensing images from Google Earth for ship detection show that our detection method based on R-DFPN representation has a state-of-the-art performance.Comment: 14 pages, 11 figure

    Identification of metabolites of kurarinone from Sophora flavescens Ait in rat urine by ultra-performance liquid chromatography with linear ion trap orbitrap mass spectrometry

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    Purpose: To study the in vivo metabolism of kurarinone, a lavandulyl flavanone which is a major constituent of Kushen and a marker compound with many biological activities, using ultra-performance liquid chromatography coupled with linear ion trap Orbitrap mass spectrometry (UPLC-LTQ-Orbitrap-MS).Methods: Six male Sprague-Dawley rats were randomly divided into two groups. First, kurarinone was suspended in 0.5 % carboxymethylcellulose sodium  (CMC-Na) aqueous solution, and was given to rats (n = 3, 2 mL for each rat) orally at 50 mg/kg. A 2 mL aliquot of 0.5 % CMC-Na aqueous solution was administered to the rats in the control group. Next, urine samples were collected over 0-24 h after the oral administrations and all urine samples were pretreated by a solid phase extraction (SPE) method. Finally, all samples were analyzed by a UPLC-LTQ-Orbitrap mass spectrometry coupled with an electrospray ionization source (ESI) that was operated in the negative ionization mode.Results: A total of 11 metabolites, including the parent drug and 10 phase II metabolites in rat urine, were first detected and interpreted based on accurate mass measurement, fragment ions, and chromatographic retention times. The results were based on the assumption that kurarinone glucuronidation was the dominant  metabolite that was excreted in rat urine.Conclusion: The results from this work indicate that kurarinone in vivo is typically transformed to nontoxic glucuronidation metabolites, and these findings may help to characterize the metabolic profile of kurarinone.Keywords: Kurarinone, Metabolites, Sophora flavescens Ait., Glucuronidation metabolite

    Study on Fatigue Property of Cracked Steel Plate Strengthened by CFRP

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    This paper presents fatigue property of CFRP-strengthened cracked steel plate. Firstly, the finite element model of CFRP-strengthened cracked steel plate is established by using the cohesive zone model. With the finite element model, stress intensity factor of the crack-tipis calculated. Then, it gives the fatigue tests of cracked steel plate. According to the experimental data, the material constants C and n value sare obtained. The prediction fatigue life is calculated by the finite element model and Paris function and verified by the experimental data. The results show that the prediction fatigue life, calculated by the finite element model and the Paris formula, is consistent with the experimental fatigue life, which verifies the accuracy of our prediction model with finite element model and the Paris function

    Magnetic resonance imaging and mammographic appearance of dermatofibrosarcoma protuberans in a male breast: a case report and literature review

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    <p>Abstract</p> <p>Introduction</p> <p>Dermatofibrosarcoma protuberans is a rare low-grade soft tissue neoplasm with trunk and extremities being the most common sites of involvement. We report a rare case of male breast with dermatofibrosarcoma protuberans and its imaging features. To our knowledge the imaging appearance of dermatofibrosarcoma protuberans of the breast has never been reported in the literature.</p> <p>Case presentation</p> <p>We report the imaging appearance of dermatofibrosarcoma protuberans on the breast of a 41-year-old Chinese man who initially presented with a palpable lump. A mammogram showed two lesions, one with well circumscribed and the other with an ill defined border, in his right breast. Conventional magnetic resonance imaging was performed and showed the well defined larger lesion with mild central hypointensity while the smaller lesion had an irregular border. Both lesions were well characterized on the fat-suppressed sequences.</p> <p>Conclusions</p> <p>Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma and its occurrence on the breast is even rarer. Mammography and magnetic resonance imaging can help in characterizing the lesion and localizing the lesion for further diagnostic evaluation and surgical planning.</p
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