Active magnetic control algorithm for small satellite

Small satellites often tumble as a result of disturbance during the initial orbit period, and it is therefore very important to capture it promptly with finite magnetic torque. Because of the coupling of dynamics and control, the control system for small satellites is a nonlinear system with restrictive conditions. Considering the restrictive conditions of magnetic torque, two algorithms are proposed: the energy algorithm which uses the Lyapunov energy depletion theory and takes the Hamilton function as a cost function to determine the magnetic torque, and the variable structure control theory which is used to deal with the magnetic torque.

Small-worldness of brain networks after brachial plexus injury: a resting-state functional magnetic resonance imaging study

Research on brain function after brachial plexus injury focuses on local cortical functional reorganization,and few studies have focused on brain networks after brachial plexus injury.Changes in brain networks may help understanding of brain plasticity at the global level.We hypothesized that topology of the global cerebral resting-state functional network changes after unilateral brachial plexus injury.Thus,in this cross-sectional study,we recruited eight male patients with unilateral brachial plexus injury（right handedness,mean age of 27.9±5.4years old）and eight male healthy controls（right handedness,mean age of 28.6±3.2）.After acquiring and preprocessing resting-state magnetic resonance imaging data,the cerebrum was divided into 90 regions and Pearson’s correlation coefficient calculated between regions.These correlation matrices were then converted into a binary matrix with affixed sparsity values of 0.1–0.46.Under sparsity conditions,both groups satisfied this small-world property.The clustering coefficient was markedly lower,while average shortest path remarkably higher in patients compared with healthy controls.These findings confirm that cerebral functional networks in patients still show smallworld characteristics,which are highly effective in information transmission in the brain,as well as normal controls.Alternatively,varied small-worldness suggests that capacity of information transmission and integration in different brain regions in brachial plexus injury patients is damaged.

Electronic and Magnetic Properties of Small Iridium Clusters

The electronic and magnetic properties of small IrN clusters (N=5, 6, 9, 13, and 19 ) are studied by using the discrete-variational local-spin-density-functional method. The equilibrium bond length in the chosen geometry for IrN clusters are determined and show bond contraction compared with the bulk interatomic spacing. The clusters with magnetic ground state have ferromagnetic interaction and their average magnetic moment per atom has a complex size dependence. At last, the reactivity of IrN clusters toward H2, N2 and CO molecules is predicted.

Study of Magnetic Force Distribution for Electromagnetic V-shape Bending Forming of Small Size Flat Sheet

Electromagnetic V-shape bending of small size sheet blank is investigated numerically and experimentally. Three-dimensional electromagnetic field models are established to calculate the magnetic force distribution on the sheet by software ANSYS / EMAG. Series of electromagnetic V-shape bending forming experiments are presented,in which small size uniform pressure coil and big size round flat spiral coil are used. The results show that small size uniform pressure coil is not suitable for electromagnetic forming of small size flat sheet,and the coil is susceptible to failure such as bulging,ablation and cracking. When the plane dimension of round flat spiral coil is bigger than sheet blank sizes,the induced current crowding effect will be resulted which seriously influence the magnetic force distribution on the sheet. In this case,magnetic force distribution can be adjusted through the change of the relative position between coil and sheet,the desired deformation can be obtained finally. Therefore,big size round flat spiral coil can be well applied to electromagnetic V-shape bending forming of small size flat sheet.

Vibrations in Magnet/Superconductor Levitation Systems

The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction energy, levitation force, magnetic stiffness and frequency of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency increases monotonically up to saturation by increasing the radius of the disc for a particular height of the magnet. In addition, the frequency of vibrations is higher when the system is in the vertical configuration than that when the system is in the horizontal configuration.

小针刀联合经颅磁刺激治疗脑梗死后遗症期上肢痉挛的疗效观察

目的:研究小针刀联合经颅磁刺激(Transcranial Magnetic Stimulation.TMS)在改善脑梗死后遗症期患者上肢痉挛症状中的临床疗效。方法:选取2021年6月~2023年6月在本院就诊的80例脑梗死后遗症期上肢轻至中度痉挛患者,随机将其分为小针刀组(n=26)、TMS组(n=27)、联合组(n=27)。所有患者在常规康复训练基础上,小针刀组进行小针刀治疗,TMS组进行经颅磁治疗,联合组进行联合治疗。治疗前后评估患者的Fugl-Meyer量表分数、临床痉挛指数分数,运动诱发电位,和静息运动阈值。结果:三组患者治疗后Fugl-Meyer评分均提高,临床痉挛指数评分均下降(P<0.01),其中联合治疗组的FuglMeyer评分高于单一治疗组,临床痉挛指数评分低于单一治疗组(P<0.01):三组患者治疗后运动诱发电位潜伏期均缩短,波幅增高(P<0.01),其中联合治疗组的运动诱发电位潜伏期短于单一治疗组,波幅高于单一治疗组(P<0.01):三组患者治疗后静息运动阈值均下降(P<0.01),其中联合治疗组的静息运动阈值低于单一治疗组(P<0.01)。结论:小针刀联合经颅磁刺激治疗能有效缓解脑梗死后上肢功能痉挛患者的上肢痉挛、中枢神经系统功能及大脑皮层兴奋性,疗效优于单一治疗方法。

Chaos in complex motor networks induced by Newman-Watts small-world connections

We investigate how dynamical behaviours of complex motor networks depend on the Newman-Watts small-world （NWSW） connections. Network elements are described by the permanent magnet synchronous motor （PMSM） with the values of parameters at which each individual PMSM is stable. It is found that with the increase of connection probability p, the motor in networks becomes periodic and falls into chaotic motion as p further increases. These phenomena imply that NWSW connections can induce and enhance chaos in motor networks. The possible mechanism behind the action of NWSW connections is addressed based on stability theory.

Value of ^(18)F-FDG PET/CT and MRI in diagnosing primary endometrial small cell carcinoma

Primary small cell carcinoma（SCC） is a group of aggressive neoplasms that mainly arise from the lung and digestive tract. Endometrial small cell carcinoma（ESCC） is extremely rare. To our knowledge, less than 90 cases have been reported, and most of these reports were dedicated to describing the clinicopathologic or immunochemical features of ESCC. Herein, we present a new case of ESCC involving a 51-year-old woman and mainly focus on the magnetic resonance imaging（MRI） and positron emission tomography/computed tomography（PET/CT） findings. MRI showed that the uterus was significantly enlarged（11.6 cm × 11.1 cm × 14.4 cm）, and a giant irregular mass（7.5 cm × 8.4 cm × 8.5 cm） was observed in the uterine cavity. The lesion demonstrated an extremely low apparent diffusion coefficient（ADC） value [（0.553±0.088）×10^–3 mm^2/s] and a high FDG uptake value（22.7）. Multiple metastatic lymph nodes（LNs） were identified at different positions, with diameters ranging from 0.3 to 2.8 cm and a maximum standardized uptake value（SUV max） ranging from 6.9 to 19.3.

Development and in vitro study of a bi-specific magnetic resonance imaging molecular probe for hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes.The iron Prussian blue staining and quantitative T2-map MRI analysis showed that,compared with UA,UG,and U,the uptake of double antigen-targeted UAG probe demonstrated a 23.3%(vs UA),15.4%(vs UG),and 57.3%(vs U)increased Prussian stained cell percentage and a 14.93%(vs UA),9.38%(vs UG),and 15.3%(vs U)reduction of T2 relaxation time,respectively.Such bi-specific probe might have the potential to overcome tumor heterogeneity.Meanwhile,the coupling of two antibodies did not influence the magnetic performance of USPIO,and the relatively small hydrodynamic size(59.60±1.87 nm)of double antibodyconjugated USPIO probe makes it a viable candidate for use in MHCC MRI in vivo,as they are slowly phagocytosed by macrophages.CONCLUSION The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly-or non-targeted USPIO,paving the way for in vivo translation to further evaluate its clinical potential.

Observational Evidences for Extremely Strong Magnetic Fields in Solar Flares

New observational data related to the X1.1/2N solar flare of 17 July 2004 were investigated and compared with some old data for other powerful flares and non-flare regions. Observations were carried out with the Echelle spectrograph of the Kyiv University Astronomical Observatory. The Stokes I ± V profiles of several metallic lines with different effective Lande factors geff have been analyzed including the FeI 5434.5 line with very low magnetic sensitivity (geff = –0.014). The obvious evidences of the emissive Zeeman effect were found as in lines with great and middle Lande factors as in FeI 5434.5 line. On the basis of all analyzed data one can conclude that upper magnetic field limit in flares can reach 70 - 90 kG, i.e. about more order higher than the well-known magnetic fields in great sunspots. The possible physical nature of such superstrong fields is discussed.

集输小口径管道腐蚀弱磁检测定量评价

集输小口径管道在油气田分布广泛,但使用传统腐蚀检测方法难度大、费用高且必须开挖取样点后才能定量评价腐蚀程度。为了弥补这种不足,实现非开挖条件下进行定量评价:分析磁偶极子模型得到腐蚀缺陷附近产生的漏磁场的磁信号特点;通过有限元仿真模拟,得到了腐蚀缺陷深度及宽度与磁信号间的关系;将SY/T 6151-2009《钢制管道管体腐蚀损伤评价方法》中对腐蚀评价所需的缺陷宽度和深度参数,结合磁偶极子模型理论推导计算与磁信号特征参数的关系,得到了一种可应用于非开挖条件下的管道腐蚀弱磁检测定量评价方法,并在某油田管道进行了工程验证,为非开挖条件下管道腐蚀检测定量评价提供一定的理论依据。

Comparison of Ising Model and Potts Model on Non-Local Directed Small-World Networks

Further to the investigation of the critical properties of the Potts model with q = 3 and 8 states in one dimension (1D) on directed small-world networks reported by Aquino and Lima, which presents, in fact, a second-order phase transition with a new set of critical exponents, in addition to what was reported in Sumour and Lima in studying Ising model on non-local directed small-world for several values of probability 0 < P < 1. In this paper the behavior of two models discussed previously, will be re-examined to study differences between their behavior on directed small-world networks for networks of different values of probability P = 0.1, 0.2, 0.3, 0.4 and 0.5 with different lattice sizes L = 10, 20, 30, 40, and 50 to compare between the important physical variables between Ising and Potts models on the directed small-world networks. We found in our paper that is a phase transitions in both Ising and Potts models depending essentially on the probability P.

经腹肠道超声和磁共振小肠造影对小肠受累克罗恩病诊断价值的对比研究

目的 探讨经腹肠道超声(IUS)与磁共振小肠造影(MRE)对于小肠受累克罗恩病(CD)患者诊断价值的对比研究。方法 回顾性纳入2018~2023年我院住院治疗存在小肠受累且同期进行过IUS及MRE的CD患者41例分析所有患者临床资料及IUS、MRE特征,比较两种影像学方法对于CD小肠病变检出情况及位置、范围、并发症的诊断价值。结果 41例患者中,男31例、女10例,年龄10~59岁,平均年龄(28.4±11.8)岁,活动期17例、缓解期24例,17例曾行CD相关手术(包括肠道手术9例及肛周手术8例)。IUS和MRE对所有CD患者及24例缓解期患者阳性病变诊断的一致性均较好(0.6<κ≤0.8);对小肠、结肠、末段回肠、空肠、回肠病变、肠瘘、有肠道手术史的CD患者阳性病变诊断的一致性均较好(0.6<κ≤0.8);对肠壁增厚诊断的一致性中等(0.4<κ≤0.6);对无肠道手术史的CD患者阳性病变的诊断完全一致。结论 IUS对小肠受累CD患者病变性质及部位诊断的准确性好,对CD患者诊断及随访有重要价值。

Comparison of the use of wireless capsule endoscopy with magnetic resonance enterography in children with inflammatory bowel disease

BACKGROUND Magnetic resonance enterography (MRE) and wireless capsule endoscopy (WCE) are equally accepted modalities for noninvasive screening of small bowel involvement (SBI) in children with Crohn’s disease (CD) and indeterminate colitis (IC) albeit there is a paucity of data comparing the two and thereby guiding the clinician in selecting the ideal diagnostic approach. Therefore, the goal of this study is to provide additional evidence for capsule endoscopy role in the evaluation of established Crohn’s disease exacerbation compared to MRE in relation to Pediatric Crohn's Disease Activity Index (PCDAI), and histological indices. AIM To prospectively compare the findings of MRE and WCE and their agreement with PCDAI or histology in children with CD or IC. METHODS Consecutive patients diagnosed with CD and IC were screened for inclusion. After informed consent, patient’s demographic and clinical data was abstracted. The current pediatric disease activity index (PCDAI) and endoscopic findings were included. Patients underwent MRE and WCE including preprocedural patency capsule within a maximum of 7 d of each other. Pathological presence of active small bowel disease in ileal and duodenal biopsies were collected if the endoscopy was performed within 2 mo of the WCE study. Patients who failed to pass the PC were excluded from the study. WCE was read by two different experienced gastroenterologists (Attard TM and Colombo JM) blinded to each other's findings and to the findings on MRE (Mardis NJ). Agreement between WCE reviewers, WCE and MRE findings and concordance between positive PCDAI and SBI based on MRE compared with WCE was computed. RESULTS Forty-five patients were included in the study, 18 withdrew and 27 (20 males and 20 CD), mean age (standard deviation) 13.46 (2.4) years, completed the study protocol. There were no instances of capsule retention. Concordance between gastroenterologist reviewers was excellent for the diagnosis of small intestinal CD with good correlation between the two Lewis scores (r=0.875, P<0.001). Concordance between WCE and MRE was poor (69%). In CD patients, when both MRE and WCE were compared using PCDAI>10 as the standard reference reflecting active small intestinal CD, the sensitivity of MRE and WCE were 100% and 83% respectively and the specificity of MRE and WCE were 57.14% and 78.6%, respectively. If the histology in ileum or/and duodenum was used as the reference for active small bowel involvement, WCE had a higher specificity as compared to MRE (83.3% vs 50%). In patients with Crohn’s disease, those with a positive PCDAI (>10) were more likely to have a positive WCE as compared to those with a negative PCDAI (83% vs 21%;P=0.018). CONCLUSION We suggest that MRE and WCE have a complementary role in the assessment of SBI in CD. WCE detected SBI with a much higher specificity while MRE had a higher sensitivity.

微分求积法分析碳纳米管磁流体输送系统的稳定性

基于磁流体动力学方程及非局部欧拉-伯努利(Euler-Bernoulli)梁模型,建立了轴向磁场作用下单壁碳纳米管磁流体输送系统的振动微分方程.应用微分求积法(DQM),在固支边界条件下,求解此高阶偏微分方程,着重研究管内磁流体效应、轴向磁场、小尺度参数(磁流体克努森数Kn与碳纳米管小尺度系数)对该系统振动与失稳特性的影响.数值计算结果表明,轴向磁场提升系统刚度及系统稳定性,而小尺度参数降低系统稳定性.更重要的是,固支边界系统中磁流体在磁场作用下,降低输送系统的刚度,但能提升输送系统的稳定性.

Isolation of γδT cells from mouse small intestine

Gamma/delta T cells (γδТ cells) are among the first lymphoid cells appearing in the ontogenesis. Many of γδТ cells are located in the small intestine/lamina propria of mice and human, where they cooperate with different cells (B-1 cells, in particular) and influence their activity. However, such interactions are studied rather scanty, and the functional role of γδТ cells in the intestine?is not yet fully elucidated. To study the interactions of mouse γδТ cells with other cells it is necessary to have purified cell populations. Unfortunately, most approaches used for isolation of human γδТ cells are not suitable for isolation of mouse γδТ cells. The aim of the present study is the modification of the method of mouse intestinal γδТ cell isolation in the quantities sufficient for the in vivo and in vitro experiments.

Magnetic resonance imaging biomarkers of gastrointestinal motor function and fluid distribution

Magnetic resonance imaging(MRI) is a well established technique that has revolutionized diagnostic radiology. Until recently, the impact that MRI has had in the assessment of gastrointestinal motor function and bowel fluid distribution in health and in disease has been more limited, despite the novel insights that MRI can provide along the entire gastrointestinal tract. MRI biomarkers include intestinal motility indices, small bowel water content and whole gut transit time. The present review discusses new developments and applications of MRI in the upper gastrointestinal tract, the small bowel and the colon reported in the literature in the last 5 years.

New progress in CT and MRI examination and diagnosis of small intestinal tumors

Precise examination and diagnosis of small intestinal tumors is difficult because of the curved course and overlapping canal of the small intestine. Traditional technology for intestinal canal examination and endoscopy cannot exhibit the intestinal wall and extra-luminal structure well. With the development and advancement of multi-slice spiral computed tomography and magnetic resonance imaging (MRI), computed tomography enteroclysis (CTE) and magnetic resonance enteroclysis (MRE) are widely used in the examination and diagnosis of small intestinal tumors. CTE and MRE, with three-dimensional imaging capabilities and excellent soft-tissue contrast, can analyze the abnormalities of peripheral intestinal structure as well as the tunica mucosa. In addition, these two technologies can clearly reveal the localization, appearance, degree of mesenteric infiltration and remote tumor metastasis, which increases our cognition of the imaging diagnosis for intestinal tumors. Here we review recent progress in imaging (CT and MRI) examination and diagnosis of small intestinal tumors.

脑白质高信号消退的研究进展

脑白质高信号(WMH)普遍存在于老年人群中,与卒中、认知、步态不稳和神经精神症状相关。WMH负荷通常随着年龄的增长而增加,但随着研究的不断深入,发现WMH是动态可变的,在发展过程中可能会部分消退,且可能伴随脑萎缩减缓和认知功能改善,但其确切发生机制、影响因素及临床意义目前尚不明确,且缺少有效逆转WMH的方法。作者综述了WMH消退的相关研究,为临床医师积极干预WMH相关影响因素,促进其在早期阶段逆转,改善患者脑健康提供参考。

转甲状腺素蛋白心脏淀粉样变的诊断与治疗研究进展

转甲状腺素蛋白心脏淀粉样变是由于转甲状腺素蛋白沉积于心脏所引起的心脏功能障碍,既往被认为是一种罕见病,其发病隐匿、进展迅速、致死率高。近年来,随着诊断技术的进步,该病的检出率不断提高,各种小分子药物的不断问世也改变了以往无药可医的局面,使其死亡率有所下降。本文主要归纳了近年来转甲状腺素蛋白心脏淀粉样变在诊断和治疗方面的最新进展。