二苯并三氧二氮穴醚及其Na(Ⅰ)、Cu(Ⅱ)和Co(Ⅱ)配合物的合成与表征

自从1969年Lchn等合成穴醚[2,2,2]似来.人们对穴醚的研究越来越感到兴趣.由于空腔效应,穴醚具有很强的配位能力和较高的选择性,它对于研究无机离子在生物体内的传输过程具有重要的意义,而且有可能用于离子的识别和分离.     

三维斑点追踪成像评价甲状腺功能亢进患者左心室收缩功能改变的应用价值

目的 探讨三维斑点追踪成像（3D-STI）技术在评价甲状腺功能亢进(甲亢)患者左心室整体收缩功能中的应用价 值。方法 选择50 例甲状腺功能亢进患者与45 例健康志愿者,获取心尖四腔心切面动态图像,存储左心室三维全容积动态图像后,运用3D-STI 软件进行脱机分析,得到两组收缩期左心室整体纵向峰值应变（GLS）、圆周峰值应变（GCS）、左心室扭转度角度峰值(LV-tw)、左心室扭力（LV-tor）、左心室心底水平旋转角度峰值（Prot-B）、左心室心尖水平旋转角度峰值（Prot-A）及左心室射血分数（LVEF）等,比较两组三维应变（3DS）指标之间的差异。结果 与正常对照组比较,甲亢组的左心室收缩功能增强,GLS、GCS 分别为（-20.47±3.08）% vs.（-18.52±4.77）%、（-28.98±3.00）% vs.（-25.88±2.12）%,两组差异均有统计学意义（均P＜0.05）;甲亢组LV-tw、LV-tor、LVProt-A、LVProt-B 均较正常对照组略有增加,但差异均无统计学意义（均P＞0.05）。结论 3D-STI 可无 创、敏感检测甲亢患者左心室三维应变,为临床客观评估甲亢左心室收缩功能提供一种新方法。     

Assessing Earthquake Forecast Performance Based on b Value in Yunnan Province,China

Many studies have shown that b values tend to decrease prior to large earthquakes. To evaluate the forecast information in b value variations, we conduct a systematic assessment in Yunnan Province, China, where the seismicity is intense and moderate–large earthquakes occur frequently. The catalog in the past two decades is divided into four time periods (January 2000–December 2004, January 2005–December 2009, January 2010–December 2014, and January 2015–December 2019). The spatial b values are calculated for each 5-year span and then are used to forecast moderate-large earthquakes (M ≥ 5.0) in the subsequent period. As the fault systems in Yunnan Province are complex, to avoid possible biases in b value computation caused by different faulting regimes when using the grid search, the hierarchical space–time point-process models (HIST-PPM) proposed by Ogata are utilized to estimate spatial b values in this study. The forecast performance is tested by Molchan error diagram (MED) and the efficiency is quantified by probability gain (PG) and probability difference (PD). It is found that moderate–large earthquakes are more likely to occur in low b regions. The MED analysis shows that there is considerable precursory information in spatial b values and the forecast efficiency increases with magnitude in the Yunnan Province. These results suggest that the b value might be useful in middle- and long-term earthquake forecasts in the study area.     

Finite-temperature phase transition in a class of four-state Potts antiferromagnets

We argue that the four-state Potts antiferromagnet has a finite-temperature phase transition on any Eulerian plane triangulation in which one sublattice consists of vertices of degree 4. We furthermore predict the universality class of this transition. We then present transfer-matrix and Monte?Carlo data confirming these predictions for the cases of the Union Jack and bisected hexagonal lattices.     

Jacobi structures of evolutionary partial differential equations

In this paper we introduce the notion of infinite dimensional Jacobi structure to describe the geometrical structure of a class of nonlocal Hamiltonian systems which appear naturally when applying reciprocal transformations to Hamiltonian evolutionary PDEs. We prove that our class of infinite dimensional Jacobi structures is invariant under the action of reciprocal transformations that only change the spatial variable. The main technical tool is in a suitable generalization of the classical Schouten–Nijenhuis bracket to the space of the so called quasi-local multi-vectors, and a simple realization of this structure in the framework of supermanifolds. These constructions are used to compute the Lichnerowicz–Jacobi cohomologies and to prove a Darboux theorem for Jacobi structures with hydrodynamic leading terms. We also introduce the notion of bi-Jacobi structures, and consider the integrability of a system of evolutionary PDEs that possesses a bi-Jacobi structure.     

Critical speeding-up in the local dynamics of the random-cluster model

We study the dynamic critical behavior of the local bond-update (Sweeny) dynamics for the Fortuin-Kasteleyn random-cluster model in dimensions d=2, 3 by Monte Carlo simulation. We show that, for a suitable range of q values, the global observable S2 exhibits "critical speeding-up": it decorrelates well on time scales much less than one sweep. In some cases the dynamic critical exponent for the integrated autocorrelation time is negative. We also show that the dynamic critical exponent zexp is very close (possibly equal) to the rigorous lower bound alpha/nu and quite possibly smaller than the corresponding exponent for the Chayes-Machta-Swendsen-Wang cluster dynamics.     

Large-scale synthesis of uniform and extremely small-sized iron oxide nanoparticles for high-resolution T1 magnetic resonance imaging contrast agents

Uniform and extremely small-sized iron oxide nanoparticles (ESIONs) of < 4 nm were synthesized via the thermal decomposition of iron-oleate complex in the presence of oleyl alcohol. Oleyl alcohol lowered the reaction temperature by reducing iron-oleate complex, resulting in the production of small-sized nanoparticles. XRD pattern of 3 nm-sized nanoparticles revealed maghemite crystal structure. These nanoparticles exhibited very low magnetization derived from the spin-canting effect. The hydrophobic nanoparticles can be easily transformed to water-dispersible and biocompatible nanoparticles by capping with the poly(ethylene glycol)-derivatized phosphine oxide (PO-PEG) ligands. Toxic response was not observed with Fe concentration up to 100 μg/mL in MTT cell proliferation assay of POPEG-capped 3 nm-sized iron oxide nanoparticles. The 3 nm-sized nanoparticles exhibited a high r(1) relaxivity of 4.78 mM(-1) s(-1) and low r(2)/r(1) ratio of 6.12, demonstrating that ESIONs can be efficient T(1) contrast agents. The high r(1) relaxivities of ESIONs can be attributed to the large number of surface Fe(3+) ions with 5 unpaired valence electrons. In the in vivo T(1)-weighted magnetic resonance imaging (MRI), ESIONs showed longer circulation time than the clinically used gadolinium complex-based contrast agent, enabling high-resolution imaging. High-resolution blood pool MR imaging using ESIONs enabled clear observation of various blood vessels with sizes down to 0.2 mm. These results demonstrate the potential of ESIONs as T(1) MRI contrast agents in clinical settings.     

Biologically Relevant Metal-Cation Binding Induces Conformational Changes in Heparin Oligosaccharides as Measured by Ion Mobility Mass Spectrometry

Heparin interacts with many proteins and is involved in biological processes such as anticoagulation, angiogenesis, and antitumorigenic activities. These heparin-protein interactions can be influenced by the binding of various metal ions to these complexes. In particular, physiologically relevant metal cations influence heparin-protein conformations through electronic interactions inherent to this polyanion. In this study, we employed ion mobility mass spectrometry (IMMS) to observe conformational changes that occur in fully-sulfated heparin octasaccharides after the successive addition of metal ions. Our results indicate that binding of positive counter ions causes a decrease in collision cross section (CCS) measurements, thus promoting a more compact octasaccharide structure.     

储存环内电子冷却过程模拟

考虑储存环内离子的横向振荡和纵向振荡的运动特性,模拟了HIRFL-CSR内重离子束的电子冷却过程.给出了离子束的横向发射度和纵向动量散度随时间连续变化的图象,由此分析了电子束的空间电荷效应,冷却段色散函数和横向电子束温度对冷却过程快慢的影响.